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Sample records for microscopic annealing process

  1. Low thermal power electron beam annealing of scanning tunneling microscope tips

    NASA Astrophysics Data System (ADS)

    Scholz, R.; Agne, M.; Breitenstein, O.; Jenniches, H.

    1997-08-01

    An add-on unit was developed that allows the cleaning of scanning tunneling microscope tips by electron beam annealing even if they cannot be disconnected from the piezo scanner in situ. The whole scanner tip combination, which is attached to a linear motion stage, is subjected to a pulsed annealing treatment. The heat impact is focused on the outermost tip by sticking the tip through a hole in a grounded Mo screening plate with the cathode mounted on the opposite side. Tungsten tips attached to the scanner of the Omicron ultrahigh vacuum Multiscan Lab were annealed to achieve atomic resolution of ultrahigh vacuum cleaved GaAs (110) faces. A highly doped superlattice package grown on semi-insulating GaAs was also able to be investigated on the cleaved (110) face due to the ability of exact tip positioning with a scanning electron microscope.

  2. Understanding the changes in ductility and Poisson's ratio of metallic glasses during annealing from microscopic dynamics

    SciTech Connect

    Wang, Z.; Ngai, K. L.; Wang, W. H.

    2015-07-21

    In the paper K. L. Ngai et al., [J. Chem. 140, 044511 (2014)], the empirical correlation of ductility with the Poisson's ratio, ν{sub Poisson}, found in metallic glasses was theoretically explained by microscopic dynamic processes which link on the one hand ductility, and on the other hand the Poisson's ratio. Specifically, the dynamic processes are the primitive relaxation in the Coupling Model which is the precursor of the Johari–Goldstein β-relaxation, and the caged atoms dynamics characterized by the effective Debye–Waller factor f{sub 0} or equivalently the nearly constant loss (NCL) in susceptibility. All these processes and the parameters characterizing them are accessible experimentally except f{sub 0} or the NCL of caged atoms; thus, so far, the experimental verification of the explanation of the correlation between ductility and Poisson's ratio is incomplete. In the experimental part of this paper, we report dynamic mechanical measurement of the NCL of the metallic glass La{sub 60}Ni{sub 15}Al{sub 25} as-cast, and the changes by annealing at temperature below T{sub g}. The observed monotonic decrease of the NCL with aging time, reflecting the corresponding increase of f{sub 0}, correlates with the decrease of ν{sub Poisson}. This is important observation because such measurements, not made before, provide the missing link in confirming by experiment the explanation of the correlation of ductility with ν{sub Poisson}. On aging the metallic glass, also observed in the isochronal loss spectra is the shift of the β-relaxation to higher temperatures and reduction of the relaxation strength. These concomitant changes of the β-relaxation and NCL are the root cause of embrittlement by aging the metallic glass. The NCL of caged atoms is terminated by the onset of the primitive relaxation in the Coupling Model, which is generally supported by experiments. From this relation, the monotonic decrease of the NCL with aging time is caused by the slowing down

  3. The Annealing Process in Solid 4He

    NASA Astrophysics Data System (ADS)

    Rittner, Ann Sophie C.; Reppy, John D.

    2007-09-01

    We have used a torsional oscillator with square cross section and a resonance frequency of 185 Hz to confirm the nonclassical rotational inertia (NCRI) discovered by Kim and Chan (Nature 427:225, 2004; Science 305:1941, 2004). We have also found a strong correlation between the NCRI signal and a high dissipation Q -1 of 4×10-6 of the oscillation above the transition temperature. Here, we present preliminary results of the annealing process in 4He at a pressure of 26 bar. When holding the temperature constant above 1 K we have observed a immediate rise in the period and a slow decay of the dissipation. The equilibrium value of Q -1 decreases with increasing temperature.

  4. Feedback regulation of microscopes by image processing.

    PubMed

    Tsukada, Yuki; Hashimoto, Koichi

    2013-05-01

    Computational microscope systems are becoming a major part of imaging biological phenomena, and the development of such systems requires the design of automated regulation of microscopes. An important aspect of automated regulation is feedback regulation, which is the focus of this review. As modern microscope systems become more complex, often with many independent components that must work together, computer control is inevitable since the exact orchestration of parameters and timings for these multiple components is critical to acquire proper images. A number of techniques have been developed for biological imaging to accomplish this. Here, we summarize the basics of computational microscopy for the purpose of building automatically regulated microscopes focus on feedback regulation by image processing. These techniques allow high throughput data acquisition while monitoring both short- and long-term dynamic phenomena, which cannot be achieved without an automated system. PMID:23594233

  5. In situ laser processing in a scanning electron microscope

    SciTech Connect

    Roberts, Nicholas A.; Magel, Gregory A.; Hartfield, Cheryl D.; Moore, Thomas M.; Fowlkes, Jason D.; Rack, Philip D.

    2012-07-15

    Laser delivery probes using multimode fiber optic delivery and bulk focusing optics have been constructed and used for performing materials processing experiments within scanning electron microscope/focused ion beam instruments. Controlling the current driving a 915-nm semiconductor diode laser module enables continuous or pulsed operation down to sub-microsecond durations, and with spot sizes on the order of 50 {mu}m diameter, achieving irradiances at a sample surface exceeding 1 MW/cm{sup 2}. Localized laser heating has been used to demonstrate laser chemical vapor deposition of Pt, surface melting of silicon, enhanced purity, and resistivity via laser annealing of Au deposits formed by electron beam induced deposition, and in situ secondary electron imaging of laser induced dewetting of Au metal films on SiO{sub x}.

  6. In situ laser processing in a scanning electron microscope

    SciTech Connect

    Roberts, Nicholas; Fowlkes, Jason Davidson; Rack, Prof. Philip; Moore, Tom; Magel, Greg; Hartfield, Cheryl

    2012-01-01

    Laser delivery probes using multimode fiber optic delivery and bulk focusing optics have been constructed and used for performing materials processing experiments within scanning electron microscope/focused ion beam instruments. Controlling the current driving a 915-nm semiconductor diode laser module enables continuous or pulsed operation down to sub-microsecond durations, and with spot sizes on the order of 50 {micro}m diameter, achieving irradiances at a sample surface exceeding 1 MW/cm{sup 2}. Localized laser heating has been used to demonstrate laser chemical vapor deposition of Pt, surface melting of silicon, enhanced purity, and resistivity via laser annealing of Au deposits formed by electron beam induced deposition, and in situ secondary electron imaging of laser induced dewetting of Au metal films on SiO{sub x}.

  7. Molecular dynamic simulation of non-melt laser annealing process

    NASA Astrophysics Data System (ADS)

    Liren, Yan; Dai, Li; Wei, Zhang; Zhihong, Liu; Wei, Zhou; Quan, Wang

    2016-03-01

    Molecular dynamic simulation is performed to study the process of material annealing caused by a 266 nm pulsed laser. A micro-mechanism describing behaviors of silicon and impurity atoms during the laser annealing at a non-melt regime is proposed. After ion implantation, the surface of the Si wafer is acted by a high energy laser pulse, which loosens the material and partially frees both Si and impurity atoms. While the residual laser energy is absorbed by valence electrons, these atoms are recoiled and relocated to finally form a crystal. Energy-related movement behavior is observed by using the molecular dynamic method. The non-melt laser anneal appears to be quite sensitive to the energy density of the laser, as a small excess energy may causes a significant impurity diffusion. Such a result is also supported by our laser anneal experiment.

  8. Toward understanding dynamic annealing processes in irradiated ceramics

    SciTech Connect

    Myers, Michael Thomas

    2013-05-01

    High energy particle irradiation inevitably generates defects in solids. The ballistic formation and thermalization of the defect creation process occur rapidly, and are believed to be reasonably well understood. However, knowledge of the evolution of defects after damage cascade thermalization, referred to as dynamic annealing, is quite limited. Unraveling the mechanisms associated with dynamic annealing is crucial since such processes play an important role in the formation of stable postirradiation disorder in ion-beam-processing of semiconductors, and determines the “radiation tolerance” of many nuclear materials. The purpose of this dissertation is to further our understanding of the processes involved in dynamic annealing. In order to achieve this, two main tasks are undertaken.

  9. Electrode patterning and annealing processes of aluminum-doped zinc oxide thin films using a UV laser system

    NASA Astrophysics Data System (ADS)

    Hsiao, Wen-Tse; Tseng, Shih-Feng; Huang, Kuo-Cheng; Chiang, Donyau

    2013-01-01

    This study presents the hybrid processing (patterning and annealing) of aluminum-doped zinc oxide (AZO) films in a one-step process using a diode-pumped-solid-state (DPSS) ultraviolet (UV) laser system. The focused laser beam had a diameter of 30 μm and the positive defocused laser beam had a diameter of 1 mm. Both beams were adjusted using a UV laser-processing system. AZO films were deposited on Corning Eagle 2000® optical glass sheets with a thickness of 0.7 mm using a sputtering method. The deposited films were approximately 200 nm. The optoelectronic properties of machined (patterning and annealing) AZO films depend on the laser pulse frequency and galvanometer scanning speed. The surface morphology, roughness, optical transmittance, and resistivity of the films after the laser patterning and annealing processes were measured using a three-dimensional confocal laser scanning microscope, a field emission scanning electron microscope (FE-SEM), a spectrophotometer, and a four-point probe instrument, respectively. Experimental results indicate that the ablation depth increased as the pulse repetition frequency increased. The ablation depth also decreased as the galvanometric scanning speed increased. The transmittance spectra of the film changes slightly after laser annealing, and the average transmittance in the visible region is approximately 83%. All resistivity values of laser-patterned and annealed AZO films decreased significantly. The structural properties grain size was calculated firm the X-ray diffraction (XRD) spectra using the Scherrer equation that increased from 7.4 nm to 12 nm as the annealing scanning speed decreased from 800 mm/s to 400 mm/s. The root mean square (RMS) values of annealed AZO films treated with a laser scanning speed of 500 mm/s with a pulse repetition frequency of 40 kHz, 55 kHz, and 70 kHz were 1.1 nm, 1.2 nm, and 1.8 nm, respectively.

  10. In situ annealing and high-rate silicon epitaxy on porous silicon by mesoplasma process

    NASA Astrophysics Data System (ADS)

    Zhang, Sheng; Lu, Ziyu; Sheng, Jiang; Gao, Pingqi; Yang, Xi; Wu, Sudong; Ye, Jichun; Kambara, Makoto

    2016-05-01

    By a mesoplasma process, a double-layer porous Si is annealed for a few seconds, by which an annealing effect similar to that of a prolonged conventional annealing process is obtained. The basic annealing process is considered to follow the classical sintering theory. However, the surface of the annealed porous Si is rough with large open voids because of H etching. The epitaxial Si films deposited on such a rough surface at a rate of 350 nm/s show a smooth surface with a low defect density compared with those deposited on a polished Si wafer, which clearly demonstrates the advantages of the cluster-assisted mesoplasma process.

  11. Influence of Microwave and Conventional Annealing Processes in Improving an Electrodeposited Nickel Interlayer Characteristics

    NASA Astrophysics Data System (ADS)

    Hassan, Abdelkarim; Noordin, Mohd Yusof; Izman, Sudin; Denni, Kurniawan

    2016-07-01

    Nickel interlayer was coated on tungsten carbide substrate by electrodeposition process for the purpose of diamond deposition. Conventional and microwave annealing processes were used to improve the adhesion strength and modify the surface composition of the electroplated nickel interlayer. The conventional annealing was conducted in a high-temperature tube furnace at 1323.15 K (1050 °C) for 20 and 60 minutes annealing durations. The microwave annealing was carried out in 2.45 GHz microwave furnace at 1303.15 K (1030 °C) for the same annealing durations as the conventional process. The annealed specimens were characterized by electron microscopy, Energy dispersive X-ray spectroscopy, and X-ray diffraction technique. Adhesion of the annealed nickel interlayer was assessed by the scratch test. The results revealed significant changes in the nickel coating composition, adhesion, and appearance. The adhesion strength of nickel interlayer annealed for the longer duration of the two processes is similar. For shorter annealing duration, the microwave-annealed coating showed better adhesion. The surface composition of the nickel interlayer was modified by the diffusion of carbon and tungsten during the microwave and conventional annealing, respectively. The microwave annealing is a promising process for producing good quality treated nickel-coated tungsten carbide specimens.

  12. An Auto-Microscope System For Image Processing

    NASA Astrophysics Data System (ADS)

    Yimo, Zhang; Heqiao, Li; Zhijin, Huang

    1989-12-01

    In this paper we present a new auto-microscope system controlled by microcomputer for image processing. The microstructure of objects can be observed and processed. A charge-coupled device (CCD) array is used as the photoelectric detector. This auto-microscope system can complete autofocusing, recognizing or screening out pattern in the field of view and automatic measuring for photomicrographing by the light intensity information sampling by CCD array. For this auto-microscope system we designed the scanning mechanism of microscope stage, adjustable holder of CCD in 5-Dimention, autofocusing mechanism and a auto-photomicrograph camera with large cassette. The autofocusing discrimination function constructed by means of self entropy is better suitable for low contrast image produced by microscope system. The geometrical features of the microscope image are selected for composing the discrimination function and this discrimination function is used for classifing the patterns in the microscope field of view by training samples. Automatically measuring light for photomicrograph is realized by the same CCD array and the controlling circuit, interface circuit and other circuits of this system are developed. Some experiments results: autofocusing, auto-screening the cell pattern in the microscope field of view are given.

  13. Thin film poly-crystalline silicon fabrication based on Rapid Thermal Annealing (RTA) process

    NASA Astrophysics Data System (ADS)

    Qian, Jun; Li, Jirong; Liao, Yang; Shi, Weimin; Kuang, Huahui; Ming, Xiuchun; Liu, Jin; Jin, Jing; Qin, Juan

    2013-12-01

    Rapid Thermal Annealing (RTA) process was introduced to the experiment of Aluminum-induced crystallization of a-Si, based on sputtering method, on low cost glass substrate. A stack of glass/Al (150 nm)/Si (220 nm) was deposited by sputtering sequentially. Samples were annealed under RTA process, then annealed in the tube annealing furnace at 400 °C for 5 h. The grain crystallization was inspected by optical microscopy (OM), ,Raman spectroscopy, X-ray diffraction (XRD),and energy dispersive spectroscopy (EDS). The preferential orientation (111) was observed, with a Raman Peak at 520.8cm-1, Different annealing periods were discussed.

  14. Effect of Secondary Annealing Process on Critical Current Density in Highly Textured Bi-2212 Superconducting System

    NASA Astrophysics Data System (ADS)

    Aksan, M. A.; Madre, M. A.; Rasekh, Sh.; Constantinescu, G.; Torres, M. A.; Diez, J. C.; Sotelo, A.; Yakinci, M. E.

    2015-09-01

    Bi-2212 samples prepared by a solid-state reaction technique have been grown from the melt using the laser floating zone method. After annealing the as-grown bars, the samples showed a good grain alignment and a high transport critical current density. Secondary annealing processes were performed on the annealed samples with the aim of producing Bi-2212 phase controlled decomposition. Hence, the Bi-2201 phase and the secondary phases, which act as effective pinning centers, were obtained with the secondary annealing process. After these thermal treatments, the transport critical current densities of samples significantly increased, when compared to the annealed ones. The maximum critical current density was achieved when the samples were subjected to secondary annealing at 680°C for 168 h with an improvement of ~80%, compared to the annealed ones. Moreover, it was found that magnetization of the secondarily annealed samples was also increased. The magnetic critical current densities in these secondary annealed samples were about 3 times higher than the values obtained for the annealed ones. These results clearly indicate that the secondary annealing processes lead to the formation of effective pinning centers in the bulk material.

  15. Rapid thermal annealing of ion implanted 6H-SiC by microwave processing

    SciTech Connect

    Gardner, J.A.; Rao, M.V.; Tian, Y.L.; Holland, O.W.; Roth, E.G.; Chi, P.H.; Ahmad, I.

    1997-03-01

    Rapid thermal processing utilizing microwave energy has been used to anneal N, P, and Al ion-implanted 6H-SiC. The microwaves raise the temperature of the sample at a rate of 200{degree}C/min vs 10{degree}C/min for conventional ceramic furnace annealing. Samples were annealed in the temperature range of 1400-1700{degree}C for 2-10 min. The implanted/annealed samples were characterized using van der Pauw Hall, Rutherford backscattering, and secondary ion mass spectrometry. For a given annealing temperature, the characteristics of the microwave-annealed material are similar to those of conventional furnace anneals despite the difference in cycle time. 19 refs., 7 figs., 3 tabs.

  16. Effect of low and high temperature anneal on process-induced damage of gate oxide

    SciTech Connect

    King, J.C.; Hu, C. . Dept. of Electrical Engineering and Computer Sciences)

    1994-11-01

    The authors have investigated the ability of high and low temperature anneals to repair the gate oxide damage due to simulated electrical stress caused by wafer charging resulting from plasma etching, etc. Even 800 C anneal cannot restore the stability in interface trap generation. Even 900 C anneal cannot repair the deteriorated charge-to-breakdown and oxide charge trapping. As a small consolation, the ineffectiveness of anneal in repairing the process-induced damage allows them to monitor the damages even at the end of the fabrication process.

  17. Microscopic information processing and communication in crowd dynamics

    NASA Astrophysics Data System (ADS)

    Henein, Colin Marc; White, Tony

    2010-11-01

    Due, perhaps, to the historical division of crowd dynamics research into psychological and engineering approaches, microscopic crowd models have tended toward modelling simple interchangeable particles with an emphasis on the simulation of physical factors. Despite the fact that people have complex (non-panic) behaviours in crowd disasters, important human factors in crowd dynamics such as information discovery and processing, changing goals and communication have not yet been well integrated at the microscopic level. We use our Microscopic Human Factors methodology to fuse a microscopic simulation of these human factors with a popular microscopic crowd model. By tightly integrating human factors with the existing model we can study the effects on the physical domain (movement, force and crowd safety) when human behaviour (information processing and communication) is introduced. In a large-room egress scenario with ample exits, information discovery and processing yields a crowd of non-interchangeable individuals who, despite close proximity, have different goals due to their different beliefs. This crowd heterogeneity leads to complex inter-particle interactions such as jamming transitions in open space; at high crowd energies, we found a freezing by heating effect (reminiscent of the disaster at Central Lenin Stadium in 1982) in which a barrier formation of naïve individuals trying to reach blocked exits prevented knowledgeable ones from exiting. Communication, when introduced, reduced this barrier formation, increasing both exit rates and crowd safety.

  18. Effects of prior deformation and annealing process on microstructure and annealing twin density in a nickel based alloy

    SciTech Connect

    Li, Zhigang; Zhang, Lanting; Sun, Nairong; Sun, Yanle; Shan, Aidang

    2014-09-15

    The nickel based alloys with different Σ3 boundary density were achieved by cold-rolling and subsequent annealing treatment. Electron backscattered diffraction analysis showed that the grain size distribution changed with the processing parameters, and the discontinuous Σ3 boundary became continuous with the increase of prior deformation level. Furthermore, the Σ3 boundary density was found to be manipulated by both grain size distribution and Σ3 boundary density per grain which showed an increasing trend with prior deformation level and annealing temperature. - Highlights: • The prior deformation amount influenced the morphology of Σ3 boundary. • The grain size was not the only factor influencing Σ3 boundary density. • The fact that grain size distribution had an important effect on Σ3 boundary density was confirmed. • The nature of grain size distribution on Σ3 boundary density was revealed. • There was a great deviation in Σ3 boundary density between experimental results and predictions.

  19. Microscopic realization of cross-correlated noise processes.

    PubMed

    Shit, Anindita; Chattopadhyay, Sudip; Banik, Suman Kumar; Chaudhuri, Jyotipratim Ray

    2010-06-01

    We present a microscopic theory of cross-correlated noise processes, starting from a Hamiltonian system-reservoir description. In the proposed model, the system is nonlinearly coupled to a reservoir composed of harmonic oscillators, which in turn is driven by an external fluctuating force. We show that the resultant Langevin equation derived from the composite system (system+reservoir+external modulation) contains the essential features of cross-correlated noise processes. PMID:20590326

  20. Improved cost-effectiveness of the block co-polymer anneal process for DSA

    NASA Astrophysics Data System (ADS)

    Pathangi, Hari; Stokhof, Maarten; Knaepen, Werner; Vaid, Varun; Mallik, Arindam; Chan, Boon Teik; Vandenbroeck, Nadia; Maes, Jan Willem; Gronheid, Roel

    2016-04-01

    This manuscript first presents a cost model to compare the cost of ownership of DSA and SAQP for a typical front end of line (FEoL) line patterning exercise. Then, we proceed to a feasibility study of using a vertical furnace to batch anneal the block co-polymer for DSA applications. We show that the defect performance of such a batch anneal process is comparable to the process of record anneal methods. This helps in increasing the cost benefit for DSA compared to the conventional multiple patterning approaches.

  1. Processing-Structure-Property Relationships in Laser-Annealed PbSe Nanocrystal Thin Films.

    PubMed

    Treml, Benjamin E; Robbins, Andrew B; Whitham, Kevin; Smilgies, Detlef-M; Thompson, Michael O; Hanrath, Tobias

    2015-01-01

    As nanocrystal (NC) synthesis techniques and device architectures advance, it becomes increasingly apparent that new ways of connecting NCs with each other and their external environment are required to realize their considerable potential. Enhancing inter-NC coupling by thermal annealing has been a long-standing challenge. Conventional thermal annealing approaches are limited by the challenge of annealing the NC at sufficiently high temperatures to remove surface-bound ligands while at the same time limiting the thermal budget to prevent large-scale aggregation. Here we investigate nonequilibrium laser annealing of NC thin films that enables separation of the kinetic and thermodynamic aspects of nanocrystal fusion. We show that laser annealing of NC assemblies on nano- to microsecond time scales can transform initially isolated NCs in a thin film into an interconnected structure in which proximate dots "just touch". We investigate both pulsed laser annealing and laser spike annealing and show that both annealing methods can produce "confined-but-connected" nanocrystal films. We develop a thermal transport model to rationalize the differences in resulting film morphologies. Finally we show that the insights gained from study of nanocrystal mono- and bilayers can be extended to three-dimensional NC films. The basic processing-structure-property relationships established in this work provide guidance to future advances in creating functional thin films in which constituent NCs can purposefully interact. PMID:25787088

  2. Effect of fuel rate and annealing process of LiFePO{sub 4} cathode material for Li-ion batteries synthesized by flame spray pyrolysis method

    SciTech Connect

    Halim, Abdul; Setyawan, Heru; Machmudah, Siti; Nurtono, Tantular; Winardi, Sugeng

    2014-02-24

    In this study the effect of fuel rate and annealing on particle formation of LiFePO{sub 4} as battery cathode using flame spray pyrolysis method was investigated numerically and experimentally. Numerical study was done using ANSYS FLUENT program. In experimentally, LiFePO{sub 4} was synthesized from inorganic aqueous solution followed by annealing. LPG was used as fuel and air was used as oxidizer and carrier gas. Annealing process attempted in inert atmosphere at 700°C for 240 min. Numerical result showed that the increase of fuel rate caused the increase of flame temperature. Microscopic observation using Scanning Electron Microscopy (SEM) revealed that all particles have sphere and polydisperse. Increasing fuel rate caused decreasing particle size and increasing particles crystallinity. This phenomenon attributed to the flame temperature. However, all produced particles still have more amorphous phase. Therefore, annealing needed to increase particles crystallinity. Fourier Transform Infrared (FTIR) analysis showed that all particles have PO4 function group. Increasing fuel rate led to the increase of infrared spectrum absorption corresponding to the increase of particles crystallinity. This result indicated that phosphate group vibrated easily in crystalline phase. From Electrochemical Impedance Spectroscopy (EIS) analysis, annealing can cause the increase of Li{sup +} diffusivity. The diffusivity coefficient of without and with annealing particles were 6.84399×10{sup −10} and 8.59888×10{sup −10} cm{sup 2} s{sup −1}, respectively.

  3. Comparison of precipitate behaviors in ultra-low carbon, titanium-stabilized interstitial free steel sheets under different annealing processes

    SciTech Connect

    Shi, J.; Wang, X.

    1999-12-01

    Ultra-low carbon, titanium-stabilized interstitial free (ULC Ti-IF) steel sheets are widely used in the automobile industry because of excellent deep drawability. The annealing process is critical to their final property, and there are two different annealing processes used in industrial production of interstitial free (IF) steel sheets, namely batch annealing and continuous annealing. In this study, precipitation behaviors of titanium IF steels, that is, TiN, TiS, Ti{sub 4}(CS){sub 2}, and TiC, the size and dispersion of TiN, TiS, and Ti{sub 4}(CS){sub 2} remained almost unchanged after either annealing process. Conversely, the average size of a TiC particle increased substantially after both annealing processes, while TiC after continuous annealing was larger than that after batch annealing due to the higher heating temperature of continuous annealing. Two new particles, FeTiP and (Ti, Mn)S, were also observed in the batch annealing process but not in continuous annealing. The structure of FeTiP and (Ti, Mn)S were studied, and furthermore the evolution of FeTiP precipitation was found to be closely related to recrystallization in batch annealing. Finally, the interrelation among processing parameters, precipitation behaviors, and final property was studied.

  4. Observation of Materials Processes in Liquids in the Electron Microscope

    SciTech Connect

    Wang, Chong M.; Liao, Honggang; Ross, Frances M.

    2015-01-01

    Materials synthesis and the functioning of devices often indispensably involve liquid media. But direct visualization of dynamic process in liquids, especially with high spatial and temporal resolution, has been challenging. For solid materials, advances in aberration corrected electron microscopy have made observation of atomic level features a routine practice. Here we discuss the extent to which one can take advantage of the resolution of modern electron microscopes to image phenomenon occuring in liquids. We will describe the fundamentals of two different experimental approaches, closed and open liquid cells. We will illustrate the capabilities of each approach by considering processes in batteries and nucleation and growth of nanoparticles from solution. We conclude that liquid cell electron microscopy appears to be duly fulfilling its role for in situ studies of nanoscale processes in liquids, revealing physical and chemical processes otherwise difficult to observe.

  5. Hand microscopes and image processing for measurement tasks

    NASA Astrophysics Data System (ADS)

    Ahlers, Rolf-Juergen; Knappe, Bernard

    1997-08-01

    Very often in industry and medical applications we meet tasks, where small microscopic structures have to be inspected. The task is not just related to visualization it is also necessary to inspect and measure features of an imaged object in an automated image processing based system. One newly developed handmicroscope, called MESOP, is presented that allows for a high quality optical inspection of workpieces and objects. Due to the concrete realization with a laptop based image processing and computing environment the handmicroscope can be applied in a mobile manner. It is positioned in front of the object. The optical head, supplied with telecentric optics and a small camera, captures the image, transfers it into the PCMCIA-based frame grabber. There the images are stored and further processed due to the necessity of the operator.

  6. Buffer layer annealing effects on the magnetization reversal process in Pd/Co/Pd systems

    NASA Astrophysics Data System (ADS)

    Fassatoui, A.; Belhi, R.; Vogel, J.; Abdelmoula, K.

    2016-12-01

    We have investigated the effect of annealing the buffer layer on the magnetization reversal behavior in Pd/Co/Pd thin films using magneto-optical Kerr microscopy. It was found that annealing the buffer layer at 150 °C for 1 h decreases the coercivity and increases the saturation magnetization and the effective magnetic anisotropy constant. This study also shows that the annealing induces a change of the magnetization reversal from a mixed nucleation and domain wall propagation process to one dominated by domain wall propagation. This result demonstrates that the main effect of annealing the buffer layer is to decrease the domain wall pinning in the Co layer, favoring the domain wall propagation mode.

  7. Influence of annealing process on texture evolution and magnetostriction in rolled Fe-Ga based alloys

    NASA Astrophysics Data System (ADS)

    Yuan, Chao; Li, Jiheng; Bao, Xiaoqian; Gao, Xuexu

    2014-08-01

    The influence of annealing process, including heating rate and final annealing atmosphere, on texture evolution and magnetostrictive performance of rolled 0.16 wt% NbC doped Fe-Ga sheets has been investigated. It demonstrates that texture evolution is closely related with heating rate, and strong Goss texture {110}<001> was obtained at 0.25 °C/min after the heating process from 900 °C to 1080 °C, accompanied with a peak value of saturation magnetostriction. Non-Goss texture and deviation from ideal {110}<001> were observed at lower or higher heating rate, resulting in the decrease in saturation magnetostriction. Compared with pure-Ar annealed sheets, the hydrogen introduced into annealing atmosphere during final treatment promoted (110) grain growth and eliminated the Nb-rich precipitates, and additional improvement in the saturation magnetostriction was observed for the same annealing protocols, with a maximum measured value, (3/2)λs=λ//-λ⊥, of 233×10-6 obtained in the final Ar/H2 annealed sheet.

  8. Enhanced visible-light photocatalytic activity of BiVO4 microstructures via annealing process

    NASA Astrophysics Data System (ADS)

    Lu, Yanjie; Shang, Huishan; Guan, Huijuan; Zhao, Yafei; Zhang, Hongsong; Zhang, Bing

    2015-12-01

    The peanut-shaped monoclinic scheelite BiVO4 crystals were synthesized via a facile one step hydrothermal method without using any templates, followed by annealing at different temperatures. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), Brunauer-Emmet-Teller (BET) and UV-vis diffuse reflectance spectra (DRS), showing that the annealing procedure could not only change the surface morphology and crystallinity of BiVO4 but also increase the specific surface area without damaging the peanut shape. The band gap values of the samples annealed at different temperatures could be reduced to 2.44-2.46 eV as compare with that of 2.47 eV of the original sample. The photocatalytic activities of BiVO4 crystals were evaluated by degradation of methylene blue in aqueous solution under artificial solar-light. Results demonstrated that the sample annealed at 450 °C exhibited the highest activity, and the photocatalytic conversion of methylene blue could reach above 94% after 150 min of irradiation.

  9. Scientific data processing for the MICROSCOPE space experiment

    NASA Astrophysics Data System (ADS)

    Hardy, Emilie; Metris, Gilles; Santos Rodrigues, Manuel; Touboul, Pierre; Chhun, Ratana; Baghi, Quentin; Berge, Joel

    The MICROSCOPE space mission aims at testing the Equivalence Principle, which states that the acceleration of a test object due to gravitation is independent of its mass and internal composition. The Equivalence Principle is at the basis of General Relativity and has been tested on-ground with a record accuracy of a few 10(-13) . However, most theories for the unification of the gravitation with the three other fundamental interactions predict that it will be violated at a level 10(-18) -10(-13) . This range cannot be reached on Earth because of the numerous perturbations in the terrestrial environment. Being performed in space, the MICROSCOPE experiment will be able to overcome these limitations in order to test the Equivalence Principle with an accuracy of 10(-15) . The instrument will be embarked on board a drag-free microsatellite orbiting the Earth, and consists in a differential electrostatic accelerometer composed of two cylindrical test masses made of different materials. The position of the masses is detected thanks to capacitive sensors, while control loops with electrostatic actuation keep them concentric, so that they both are submitted to the same gravitational field. The electrostatic acceleration applied to the masses to maintain them relatively motionless are measured and will demonstrate a violation of the Equivalence Principle if found unequal. The potential Equivalence Principle violation signal is expected at a well identified frequency, f _{EP}. However, the raw measurement is impacted by systematic instrumental errors, which are calibrated in-orbit during dedicated sessions. The data processing therefore includes the correction of the measurement in order to reduce the contribution of these errors at f _{EP}. Other perturbations must be considered during the data analysis: numerical effects arise from the finite time span of the measurement. A procedure have thus been determined in order to extract the Equivalence Principle violation parameter

  10. Continuous-wave laser annealing of Si-rich oxide: A microscopic picture of macroscopic Si-SiO{sub 2} phase separation

    SciTech Connect

    Khriachtchev, Leonid; Nikitin, Timur; Raesaenen, Markku; Domanskaya, Alexandra; Boninelli, Simona; Iacona, Fabio; Engdahl, Anders; Juhanoja, Jyrki; Novikov, Sergei

    2010-12-15

    We report on the first observation of the macroscopic (long-range) Si-SiO{sub 2} phase separation in Si-rich oxide SiO{sub x}(x<2) obtained by continuous-wave laser annealing of free-standing SiO{sub x} films. The effect is analyzed by a unique combination of microscopic methods (Raman, transmission, photoluminescence, and infrared spectroscopy, transmission electron microscopy, electron energy loss spectroscopy, and x-ray photoelectron spectroscopy). Three regions can be distinguished on a SiO{sub x} free-standing film after 488 nm laser annealing at intensities above {approx}10{sup 4} W cm{sup -2}: central spot, ring around the central spot, and pristine film outside the irradiated area. In the pristine SiO{sub x} material, small Si nanocrystals (Si-nc) (diameters of a few nanometer) are surrounded by SiO{sub 2} with an addition of residual suboxides, the Si-nc being produced by annealing at 1100 deg. C in a furnace. The central spot of the laser-annealed area (up to {approx}30 {mu}m wide in these experiments) is practically free of Si excess and mainly consists of amorphous SiO{sub 2}. The ring around the central spot contains large spherical Si-nc (diameters up to {approx}100 nm) embedded in amorphous SiO{sub 2} without the presence of suboxides. Laser-induced temperatures in the structurally modified regions presumably exceed the Si melting temperature. The macroscopic Si-SiO{sub 2} phase separation is connected with extensive diffusion in temperature gradient leading to the Si concentration gradient. The present work demonstrates the advantages of high spatial resolution for analysis in materials research.

  11. Growth of SiC thin films on (100) and (111) silicon by pulsed laser deposition combined with a vacuum annealing process

    SciTech Connect

    Huang, J.; Wang, L.; Wen, J.; Wang, Y.; Lin, C.; Zetterling, C.M.; Oestling, M.

    1999-07-01

    Crystalline 3C-SiC thin films were successfully grown on (100) and (111) Si substrates by using ArF pulsed laser ablation from a SiC ceramic target combined with a vacuum annealing process. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were employed to study the effect of annealing on the structure of thin films deposited at 800 C. It was demonstrated that vacuum annealing could transform the amorphous SiC films into crystalline phase and that the crystallinity was strongly dependent on the annealing temperature. For the samples deposited on (100) and (111) Si, the optimum annealing temperatures were 980 and 920 C, respectively. Scanning electron microscope (SEM) micrographs exhibited different characteristic microstructure for the (100) and (111) Si cases, similar to that observed for the carbonization layer initially formed in chemical vapor deposition of SiC films on Si. This also showed the presence of the epitaxial relationship of 3C-SiC[100]//Si[100] and 3C-SiC[111]//Si[111] in the direction of growth.

  12. A microscopic lane changing process model for multilane traffic

    NASA Astrophysics Data System (ADS)

    Lv, Wei; Song, Wei-guo; Liu, Xiao-dong; Ma, Jian

    2013-03-01

    In previous simulations lane-changing behavior is usually assumed as an instantaneous action. However, in real traffic, lane changing is a continuing process which can seriously affect the following cars. In this paper, a microscopic lane-changing process (LCP) model is clearly described. A new idea of simplifying the lane-changing process to the car-following framework is presented by controlling fictitious cars. To verify the model, the results of flow, lane-changing frequency, and single-car velocity are extracted from experimental observations and are compared with corresponding simulation. It is found that the LCP model agrees well with actual traffic flow and lane-changing behaviors may induce a 12%-18% reduction of traffic flow. The results also reflect that most of the drivers on the two roads in a city are conservative but not aggressive to change lanes. Investigation of lane-changing frequency shows that the largest lane-changing frequency occurs at a medium density range from 15 vehs km lane to 35 vehs km lane. It also implies that the lane-changing process might strengthen velocity variation at medium density and weaken velocity variation at high density. It is hoped that the idea of this study may be helpful to promote the modeling and simulation study of traffic flow.

  13. Low resistive p-type GaN using two-step rapid thermal annealing processes

    SciTech Connect

    Scherer, M.; Schwegler, V.; Seyboth, M.; Kirchner, C.; Kamp, M.; Pelzmann, A.; Drechsler, M.

    2001-06-15

    Two-step thermal annealing processes were investigated for electrical activation of magnesium- doped galliumnitride layers. The samples were studied by room-temperature Hall measurements and photoluminescence spectroscopy at 16 K. After an annealing process consisting of a short-term step at 960{degree}C followed by a 600{degree}C dwell step for 5 min a resistivity as low as 0.84 {Omega}cm is achieved for the activated sample, which improves the results achieved by standard annealing (800{degree}C for 10 min) by 25% in resistivity and 100% in free hole concentration. Photoluminescence shows a peak centered at 3.0 eV, which is typical for Mg-doped samples with high free hole concentrations.{copyright} 2001 American Institute of Physics.

  14. Effect of annealing process on the phase formation in poly(vinylidene fluoride) thin films

    SciTech Connect

    Abdullah, Ibtisam Yahya; Yahaya, Muhammad; Jumali, Mohd Hafizuddin Haji; Shanshool, Haider Mohammed

    2014-09-03

    This work reports the initial study on the effect of annealing process on the crystalline phase of poly(vinylidene fluoride) (PVDF) thin film. PVDF powder was dissolved in N,N-dimethylformamide before spin-coated onto a glass substrate to form a film. The films were annealed at 30°C, 90°C and 110°C for 5 hrs. The crystalline phase of the powder PVDF as received was investigated by using XRD and FTIR techniques. Moreover, the crystalline phases of thin films after annealing were investigated by using the same techniques. XRD analysis showed that in powder form PVDF exists in α-phase. Each annealed PVDF thin films exhibited identical formation of three-phases material namely γ (as major phase) while α and β phases as the minor phases. The FTIR analysis showed that the powder form of PVDF exists in α and β phases. FTIR measurement further confirmed the XRD results implying that the annealing process has no significant effect on the phase formation in PVDF films.

  15. Annealing Characteristics of Ultrafine Grained Low-Carbon Steel Processed by Differential Speed Rolling Method

    NASA Astrophysics Data System (ADS)

    Hamad, Kotiba; Ko, Young Gun

    2016-05-01

    The annealing behavior of ultrafine grained ferrite in low-carbon steel (0.18 wt pct C) fabricated using a differential speed rolling (DSR) process was examined by observing the microstructural changes by electron backscatter diffraction and transmission electron microscopy. For this purpose, the samples processed by 4-pass DSR at a roll speed ratio of 1:4 for the lower and upper rolls, respectively, were annealed isochronally at temperatures ranging from 698 K to 898 K (425 °C to 625 °C) for 1 hour. The deformed samples exhibited a complex microstructure in the ferrite phase consisting of an equiaxed structure with a mean grain size of ~0.4 µm and a lamellar structure with a mean lamellar width of ~0.35 µm. The texture evolved during deformation was characterized by the rolling and shear components with specific orientations. After annealing at temperatures lower than 798 K (525 °C), the aspect ratio of the deformed grains tended to shift toward a unit corresponding to the equiaxed shape, whereas the grain size remained unchanged as the annealing temperature increased. At temperatures above 798 K (525 °C), however, some grains with a low dislocation density began to appear, suggesting that the starting temperature of static recrystallization in the severely deformed ferrite grains was 798 K (525 °C). The annealing texture of the present sample after heat treatment showed a uniform fiber texture consisting of α- and γ-components.

  16. Effects of annealing process on magnetic properties and structures of Nd-Pr-Ce-Fe-B melt-spun powders

    NASA Astrophysics Data System (ADS)

    Pei, Kun; Lin, Min; Yan, Aru; Zhang, Xing

    2016-05-01

    The effects of annealing process on magnetic properties and structures of Nd-Pr-Ce-Fe-B melt-spun powders have been investigated. The magnetic properties improve a lot when the annealing temperature is 590-650 °C and the annealing time exceeds 1 min. The magnetic properties is stable when the annealing time is 590-650 °C. The powders contains obvious grains when the annealing time is only 1 min, while the grains grow up obviously, leading to the decrease of Br and (BH)max, when the annealing time is more than 9 min. The Hcj changes little for different annealing time. The cooling rate also affects the magnetic properties of powders with different Ce-content. Faster cooling rate is favorable to improve magnetic properties with low Ce-content powders, while high Ce-content powders need slower cooling rate.

  17. Processing of Mn-Al nanostructured magnets by spark plasma sintering and subsequent rapid thermal annealing

    NASA Astrophysics Data System (ADS)

    Saravanan, P.; Vinod, V. T. P.; Černík, Miroslav; Selvapriya, A.; Chakravarty, Dibyendu; Kamat, S. V.

    2015-01-01

    The potential of spark plasma sintering (SPS) in combination with rapid thermal annealing (RTA) for the processing of Mn-Al nanostructured magnets is explored in this study. Ferromagnetic α-Mn alloy powders were processed by high-energy ball milling using Mn (56 at%) and Al (44 at%) as constituent metal elements. The alloying action between Mn and Al due to intensive milling was studied by X-ray diffraction and field-emission scanning electron microscope; while the phase transformation kinetics was investigated using differential scanning calorimetry. The evolution of ferromagnetic properties in the as-milled powders was studied by superconducting quantum interference device (SQUID). Among the Mn-Al alloy powders collected at various milling intervals, the 25 h milled Mn-Al powders showed a good combination of coercivity, Hc (11.3 kA/m) and saturation magnetization, Ms (5.0 A/m2/kg); accordingly, these powders were chosen for SPS. The SPS experiments were conducted at different temperatures: 773, 873 and 973 K and its effect on the density, phase composition and magnetic properties of the Mn-Al bulk samples were investigated. Upon increasing the SPS temperature from 773 to 973 K, the bulk density was found to increase from 3.6 to 4.0 g/cm3. The occurrence of equilibrium β-phase with significant amount of γ2-phase was obvious at all the SPS temperatures; however, crystallization of some amount of τ-phase was evident at 973 K. Irrespective of the SPS temperatures, all the samples demonstrated soft magnetic behavior with Hc and Ms values similar to those obtained for the 25 h milled powders. The magnetic properties of the SPSed samples were significantly improved upon subjecting them to RTA at 1100 K. Through the RTA process, Hc values of 75, 174 and 194 kA/m and Ms values of 19, 21 and 28 A/m2/kg were achieved for the samples SPSed at 773, 873 and 973 K, respectively. The possible reasons for the observed improvement in the magnetic properties of the SPSed

  18. Evaluation of deformation-induced transformation and reversion processes of stainless steel by acoustic microscope

    NASA Astrophysics Data System (ADS)

    Kasuga, Yukio; Endo, Tomio; Miyasaka, Chiaki; Kasano, Hideaki

    1999-02-01

    Deformation-induced martensite and reversed austenite of a metastable austenitic stainless steel sheet were evaluated by a scanning acoustic microscope with frequencies 600MHz and 800 MHz. The sheet was elongated up to 40 percent at and below the room temperature to produce martensite, followed by annealing for reversion. First martensite content was measured by a Feritscope. Next using a complex V(z) curve, leaky Rayleigh wave velocity was measured. The deformed and annealed grain structure s were observed with the frequency 800MHz and compared with those by the optical microscope. Rayleigh wave velocity is dependent on the elongation and ambient temperature in elongation and the annealing temperature, which agrees well with the one by the Feritscope. Deformed grains are more clearly observed by the scanning acoustic microscope with 800MHz. The measured value of the velocity is compared with the theoretical one which can be calculated by Young's modulus, Poisson's ratio and the density. The measured Rayleigh wave velocity is well agreement with the theoretical one.

  19. Gas expanded polymer process to anneal nanoparticle dispersion in thin films

    DOE PAGESBeta

    Ambuken, Preejith V.; Stretz, Holly A.; Dadmun, Mark; Michael Kilbey, S.

    2015-04-21

    A spin-coating solution comprising poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) nanoparticles used to create organic photovoltaic (OPV) active layers have been shown to adopt a non-uniform concentration profile across the thin film dimension. This inhomogeneous distribution can reduce the efficiency of the device. For our new process, gas expanded polymer (GXP) annealing, is applied to P3HT/PCBM thin film blends, enabling the distribution of the PCBM nanoparticles to be manipulated by varying the GXP processing conditions. Films of 50 nm thickness (nominally) created by spin casting a blend of P3HT mixed with PCBM were annealed by oscillatory GXP andmore » GXP at constant pressure using high pressure CO2. An increase in P3HT crystallinity (detected by X-ray diffraction and UV-vis spectroscopy) along with a more uniform distribution of PCBM nanoparticles in the thickness dimension, as interpreted from neutron reflectivity measurements, were observed after oscillatory GXP annealing. In addition, static water contact angles suggest that the film/air interface is enriched in PCBM relative to the as-cast film. Finally, these results demonstrate that GXP annealing, which is commercially scalable, can be successfully used to create a uniform distribution of PCBM nanoparticles across the thickness dimension in a P3HT thin film.« less

  20. Gas expanded polymer process to anneal nanoparticle dispersion in thin films

    SciTech Connect

    Ambuken, Preejith V.; Stretz, Holly A.; Dadmun, Mark; Michael Kilbey, S.

    2015-04-21

    A spin-coating solution comprising poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) nanoparticles used to create organic photovoltaic (OPV) active layers have been shown to adopt a non-uniform concentration profile across the thin film dimension. This inhomogeneous distribution can reduce the efficiency of the device. For our new process, gas expanded polymer (GXP) annealing, is applied to P3HT/PCBM thin film blends, enabling the distribution of the PCBM nanoparticles to be manipulated by varying the GXP processing conditions. Films of 50 nm thickness (nominally) created by spin casting a blend of P3HT mixed with PCBM were annealed by oscillatory GXP and GXP at constant pressure using high pressure CO2. An increase in P3HT crystallinity (detected by X-ray diffraction and UV-vis spectroscopy) along with a more uniform distribution of PCBM nanoparticles in the thickness dimension, as interpreted from neutron reflectivity measurements, were observed after oscillatory GXP annealing. In addition, static water contact angles suggest that the film/air interface is enriched in PCBM relative to the as-cast film. Finally, these results demonstrate that GXP annealing, which is commercially scalable, can be successfully used to create a uniform distribution of PCBM nanoparticles across the thickness dimension in a P3HT thin film.

  1. Kinetic investigation of sulfidizing annealing of scorodite in processing of refractory oxidized gold-containing ores

    NASA Astrophysics Data System (ADS)

    Boboev, I. R.; Strizhko, L. S.; Bobozoda, Sh.; Gorbunov, E. P.

    2016-03-01

    The results of kinetic studies on the removal of arsenic from scorodite using sulfidizing annealing are presented. The reaction order with respect to the reactant and the activation energy are established from the experimental data. The rate-determining step of the sulfidizing annealing process is determined. The main reactions that occur during the sulfidizing of arsenic in scorodite are proposed on the basis of the obtained results and confirmed by thermodynamic calculations and chemical analyses. The major results of testing this technology, as applied to the refractory oxidized ores in which arsenic is mainly concentrated in scorodite, are presented. Arsenic removal from this ore is confirmed by chemical and quantitative X-ray diffraction analyses and by qualitative phase analysis. Industrial use of this technology provides safe and efficient processing of refractory gold-containing ores, where arsenic is mainly concentrated in scorodite.

  2. Evolution of microstructure in vanadium oxide bolometer film during annealing process

    NASA Astrophysics Data System (ADS)

    Su, Yu-Yu; Cheng, Xing-Wang; Li, Jing-Bo; Dou, Yan-Kun; Rehman, Fida; Su, De-Zhi; Jin, Hai-Bo

    2015-12-01

    Vanadium oxide thin films were prepared through direct current magnetron reactive sputtering and post annealing process. The evolution of composition, microstructure, and electrical properties of as-deposited amorphous films during the annealing process was clarified by X-ray diffraction, scanning electron microscopy and temperature-dependent resistance measurement. A new composition of thin film was acquired which consisted of crystalline V6O13 and amorphous phase. Sheet resistance and temperature coefficient of resistance (TCR) of the thin film are 90 kΩ/□ (measured at room temperature) and 2.52%/K, respectively. No metal-to-semiconductor transition was observed in the obtained film at temperatures ranging from room-temperature to 90 °C, suggesting the thin film is suitable for the application in microbolometer.

  3. Processing of silicon solar cells by ion implantation and laser annealing

    NASA Technical Reports Server (NTRS)

    Minnucci, J. A.; Matthei, K. W.; Greenwald, A. C.

    1981-01-01

    Methods to improve the radiation tolerance of silicon cells for spacecraft use are described. The major emphasis of the program was to reduce the process-induced carbon and oxygen impurities in the junction and base regions of the solar cell, and to measure the effect of reduced impurity levels on the radiation tolerance of cells. Substrates of 0.1, 1.0 and 10.0 ohm-cm float-zone material were used as starting material in the process sequence. High-dose, low-energy ion implantation was used to form the junction in n+p structures. Implant annealing was performed by conventional furnace techniques and by pulsed laser and pulsed electron beam annealing. Cells were tested for radiation tolerance at Spire and NASA-LeRC. After irradiation by 1 MeV electrons to a fluence of 10 to the 16th power per sq cm, the cells tested at Spire showed no significant process induced variations in radiation tolerance. However, for cells tested at Lewis to a fluence of 10 to the 15th power per sq cm, ion-implanted cells annealed in vacuum by pulsed electron beam consistently showed the best radiation tolerance for all cell resistivities.

  4. Microstructure Analysis on 6061 Aluminum Alloy after Casting and Diffuses Annealing Process

    NASA Astrophysics Data System (ADS)

    Wang, H. Q.; Sun, W. L.; Xing, Y. Q.

    One factory using semi-continuous casting process produce the ф200×6000 mm 6061 aluminium alloy barstock, and then rotary forged for car wheels. 6061 distorting aluminium alloy is an forged aluminum alloy, and mainly containing Mg, Si, Cu and other alloying elements. The main strengthening phase is Mg2Si, and also has few phase of (FeMn) 3Si2Al15. In order to eliminate the segregation and separation which present in the crystal boundary, and make the distortion to be uniform, and does not present ear and fracture defects after the forging. So the 6061 distorting aluminium alloy adopt the diffusion annealing heat treatment before the forging process.According to the current conditions, we use the diffusion annealing which have the different heating temperature and different holding time.The best process we can obtain from the test which can improve the production efficiency and reduce the material waste, improve the mechanical properties, and eliminate the overheated film on the surface.Then,we using OM,SEM and EDS to analyse the microstructure and the chemical composition of compound between the surface and centre. The result shows that the amount of segregation were different in the surface and in the center, and the different diffusion annealing can cause the phase change in the surface and the center.

  5. Data-based hybrid tension estimation and fault diagnosis of cold rolling continuous annealing processes.

    PubMed

    Liu, Qiang; Chai, Tianyou; Wang, Hong; Qin, Si-Zhao Joe

    2011-12-01

    The continuous annealing process line (CAPL) of cold rolling is an important unit to improve the mechanical properties of steel strips in steel making. In continuous annealing processes, strip tension is an important factor, which indicates whether the line operates steadily. Abnormal tension profile distribution along the production line can lead to strip break and roll slippage. Therefore, it is essential to estimate the whole tension profile in order to prevent the occurrence of faults. However, in real annealing processes, only a limited number of strip tension sensors are installed along the machine direction. Since the effects of strip temperature, gas flow, bearing friction, strip inertia, and roll eccentricity can lead to nonlinear tension dynamics, it is difficult to apply the first-principles induced model to estimate the tension profile distribution. In this paper, a novel data-based hybrid tension estimation and fault diagnosis method is proposed to estimate the unmeasured tension between two neighboring rolls. The main model is established by an observer-based method using a limited number of measured tensions, speeds, and currents of each roll, where the tension error compensation model is designed by applying neural networks principal component regression. The corresponding tension fault diagnosis method is designed using the estimated tensions. Finally, the proposed tension estimation and fault diagnosis method was applied to a real CAPL in a steel-making company, demonstrating the effectiveness of the proposed method. PMID:21954208

  6. Synthesis mechanism of heterovalent Sn2O3 nanosheets in oxidation annealing process

    NASA Astrophysics Data System (ADS)

    Zhao, Jun-Hua; Tan, Rui-Qin; Yang, Ye; Xu, Wei; Li, Jia; Shen, Wen-Feng; Wu, Guo-Qiang; Yang, Xu-Feng; Song, Wei-Jie

    2015-07-01

    Heterovalent Sn2O3 nanosheets were fabricated via an oxidation annealing process and the formation mechanism was investigated. The temperature required to complete the phase transformation from Sn3O4 to Sn2O3 was considered. Two contrasting experiments showed that both oxygen and heating were not necessary conditions for the phase transition. Sn2O3 was formed under an argon protective atmosphere by annealing and could also be obtained at room temperature by exposing Sn3O4 in atmosphere or dispersing in ethanol. The synthesis mechanism was proposed and discussed. This fundamental research is important for the technological applications of intermediate tin oxide materials. Project supported by the National Natural Science Foundation of China (Grant Nos. 21377063, 51102250, 21203226, and 21205127) and the Personnel Training Foundation of Quzhou University, China (Grant No. BSYJ201412).

  7. Sb-Te alloy nanostructures produced on a graphite surface by a simple annealing process

    NASA Astrophysics Data System (ADS)

    Kuwahara, Masashi; Uratsuji, Hideaki; Abe, Maho; Sone, Hayato; Hosaka, Sumio; Sakai, Joe; Uehara, Yoichi; Endo, Rie; Tsuruoka, Tohru

    2015-08-01

    We have produced Sb-Te alloy nanostructures from a thin Sb2Te3 layer deposited on a highly oriented pyrolytic graphite substrate using a simple rf-magnetron sputtering and annealing technique. The size, shape, and chemical composition of the structures were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM), and energy dispersive X-ray spectrometry (EDX), respectively. The shape of the nanostructures was found to depend on the annealing temperature; nanoparticles appear on the substrate by annealing at 200 °C, while nanoneedles are formed at higher temperatures. Chemical composition analysis has revealed that all the structures were in the composition of Sb:Te = 1:3, Te rich compared to the target composition Sb2Te3, probably due to the higher movability of Te atoms on the substrate compared with Sb. We also tried to observe the production process of nanostructures in situ using SEM. Unfortunately, this was not possible because of evaporation in vacuum, suggesting that the formation of nanostructures is highly sensitive to the ambient pressure.

  8. Observation of the freeze-drying process of biological materials with a scanning electron microscope.

    PubMed

    Nei, T; Fujikawa, S

    1976-10-01

    Over the past few decades, numerous studies have been done on the freeze-drying of biological materials from a physical, chemical and biological point of view. Morphological observation of the freeze-drying process of specimens, however, has been tried by only a few investigators. In those studies, thin-layered aqueous specimens, which were sandwiched between two cover slips, were mostly observed with an optical microscope. For ultrastructural and stereoscopic observation, the scanning electron microscope has a great advantage, unlike that of the optical microscope. A specially designed cryo-scanning electron microscope, employed in the present study, made it possible to observe the freezing patterns of the specimens and also the sublimation process of ice in frozen specimens under vacuum. With this specially designed microscope, shrinkage of some specimens due to dehydration during the freeze-drying process was revealed and the extent of such shrinkage was quantitatively determined. PMID:1036327

  9. Effect of annealing on the laser induced damage of polished and CO2 laser-processed fused silica surfaces

    NASA Astrophysics Data System (ADS)

    Doualle, T.; Gallais, L.; Cormont, P.; Donval, T.; Lamaignère, L.; Rullier, J. L.

    2016-06-01

    We investigate the effect of different heat treatments on the laser-induced damage probabilities of fused silica samples. Isothermal annealing in a furnace is applied, with different temperatures in the range 700-1100 °C and 12 h annealing time, to super-polished fused silica samples. The surface flatness and laser damage probabilities at 3 ns, 351 nm are measured before and after the different annealing procedures. We have found a significant improvement of the initial laser damage probabilities of the silica surface after annealing at 1050 °C for 12 h. A similar study has been conducted on CO2 laser-processed sites on the surface of the samples. Before and after annealing, we have studied the morphology of the sites, the evolution of residual stress, and the laser-induced damage threshold measured at 351 nm, 3 ns. In this case, we observe that the laser damage resistance of the laser created craters can reach the damage level of the bare fused silica surface after the annealing process, with a complete stress relieve. The obtained results are then compared to the case of local annealing process by CO2 laser irradiation during 1 s, and we found similar improvements in both cases. The different results obtained in the study are compared to numerical simulations made with a thermo-mechanical model based on finite-element method that allows the simulation of the isothermal or the local annealing process, the evolution of stress and fictive temperature. The simulation results were found to be very consistent with experimental observations for the stresses evolution after annealing and estimation of the heat affected area during laser-processing based on the density dependence with fictive temperature. Following this work, the temperature for local annealing should reach 1330-1470 °C for an optimized reduction of damage probability and be below the threshold for material removal, whereas furnace annealing should be kept below the annealing point to avoid sample

  10. The effect of non-contact heating (microwave irradiation) and contact heating (annealing process) on properties and performance of polyethersulfone nanofiltration membranes

    NASA Astrophysics Data System (ADS)

    Mansourpanah, Y.; Madaeni, S. S.; Rahimpour, A.; Farhadian, A.

    2009-07-01

    In this work the effect of microwave irradiation on morphology and performance of polyethersulfone (PES) membranes was investigated. The membranes were prepared with 20 wt.% of PES by phase inversion method. N, N-dimethylformamide (DMF) and mixture of water and ethyl alcohol (90/10 vol.%) were employed as solvent and coagulant respectively. Polyvinylpirrolidone (PVP) with the concentration of 2 wt.% was selected as pore former. The effects of irradiation time (10, 30, 60, 90, 120 s) and microwave power (180, 360, 720 and 900 W) on structure and performance of membranes were studied. Increasing the irradiation time and power caused variation in permeate flux and ion rejection. Moreover, the effects of annealing processes (60, 70, 80 °C) were studied. Transmembrane pressure was selected around 1.5 MPa for all experiments. Scanning electron microscope (SEM) and atomic force microscope (AFM) were employed to describe the surface morphology of the prepared membranes. The effect of microwave irradiation time in different power revealed alterations in membrane surface morphology and AFM images represented that surface parameters (such as surface roughness) have been changed. The membrane exhibited moderate rejection (47%) and low permeate flux (4.5 kg/m 2 h) at 80 °C for NaCl solution. The SEM images indicate that the dense skin layer is formed at 80 °C annealing.

  11. Current-voltage characteristic and sheet resistances after annealing of femtosecond laser processed sulfur emitters for silicon solar cells

    NASA Astrophysics Data System (ADS)

    Gimpel, Thomas; Guenther, Kay-Michael; Kontermann, Stefan; Schade, Wolfgang

    2014-08-01

    The characteristics of laser doped sulfur emitters are strongly dependent on annealing processes. We show how annealing increases the efficiency of silicon solar cells with such an emitter. Sheet resistance analysis reveals that up to an annealing temperature of 400 °C the emitter sheet resistivity increases. A lower sulfur donor concentration is concluded, which likely occurs by means of sulfur diffusion and capturing of sulfur donors at intrinsic silicon defects. Above that temperature, the emitter sheet resistance decreases, which we find to originate from healing of laser induced structural defects involving traps within the depletion zone of the silicon pn-junction.

  12. Reconciling historical and contemporary evidence of aeolian-based, gully annealing processes in Glen, Marble, and Grand Canyon, USA

    NASA Astrophysics Data System (ADS)

    Sankey, J. B.; Draut, A. E.

    2013-12-01

    In the absence of large Colorado River floods in Glen, Marble, and Grand Canyons since the completion of Glen Canyon Dam, the geomorphic process most able to counteract the effects of gully incision on terraces and slopes above the contemporary active Colorado River channel is aeolian sand transport that can partially or entirely fill (anneal) small gullies. Whereas gully-formation processes have been much studied, relatively little is known about processes of gully annealing. Aeolian-based annealing has been observed in several instances in the modern Colorado River corridor operating on time scales of months. However, individual, short-term occurrences of aeolian deposition that counteract gully erosion have not yet been expanded into a landscape-scale evaluation of the prevalence of gully-annealing processes over longer time scales (years-decades) along the post-dam corridor. The extent that aeolian or other annealing processes might slow, or temporarily reverse, gully incision and erosion is important in this system because of the propensity for erosion damage to locations of cultural significance that are extensive on terraces and slopes above the contemporary active Colorado River channel. Moreover, the reduction of mainstem fluvial sediment inputs to the system since completion of Glen Canyon Dam might impact the potential of aeolian redistribution of Colorado River-derived sediment as an effective gully annealing mechanism on upper slopes and terraces. We present an investigation of the extent that observations of (i) historical annealing and (ii) contemporary annealing potential, reconcile with (iii) literature and/or model-based estimates of relative rates of gully formation and aeolian deposition in this system. The central question of this work is whether these complimentary lines of evidence support aeolian infilling as a viable mechanism for annealing gullies in Glen, Marble, and Grand Canyons, and analogous systems. We examine the evidence for

  13. Nanoscale thermal processing using a heated atomic force microscope tip

    NASA Astrophysics Data System (ADS)

    Nelson, Brent A.

    This dissertation aims to advance the current state of use of silicon atomic force microscope (AFM) cantilevers with integrated heaters. To this end, the research consists of two primary thrusts---demonstrating new applications for the cantilevers, and advancing the current state of understanding of their thermal and mechanical behavior to enable further applications. Among new applications, two are described. In the first application, the cantilevers are used for nanoscale material deposition, using heat to modulate the delivery of material from the nanoscale tip. In the second application, the cantilever performs thermal analysis with nanoscale spatial resolution, enabling thermal characterization of near surface and composite interphase regions that cannot be measured with bulk analysis techniques. The second thrust of the research seeks to address fundamental questions concerning the precision use of heated cantilevers. Efforts to this end include characterizing the mechanical, electrical, and thermal behavior of the cantilevers, and optimizing calibration methodology. A technique is developed for calibrating the cantilever spring constant while operating at elevated temperature. Finally, an analytical model is developed for the heat flow in the cantilever tip and relevant dimensionless numbers that govern the relative importance of the various components of the thermal environment are identified. The dimensionless numbers permit exploration of the sensitivity of the tip-substrate interface temperature to the environmental conditions.

  14. A low thermal impact annealing process for SiO{sub 2}-embedded Si nanocrystals with optimized interface quality

    SciTech Connect

    Hiller, Daniel Gutsch, Sebastian; Hartel, Andreas M.; Zacharias, Margit; Löper, Philipp; Gebel, Thoralf

    2014-04-07

    Silicon nanocrystals (Si NCs) for 3rd generation photovoltaics or optoelectronic applications can be produced by several industrially compatible physical or chemical vapor deposition technologies. A major obstacle for the integration into a fabrication process is the typical annealing to form and crystallize these Si quantum dots (QDs) which involves temperatures ≥1100  °C for 1 h. This standard annealing procedure allows for interface qualities that correspond to more than 95% dangling bond defect free Si NCs. We study the possibilities to use rapid thermal annealing (RTA) and flash lamp annealing to crystallize the Si QDs within seconds or milliseconds at high temperatures. The Si NC interface of such samples exhibits huge dangling bond defect densities which makes them inapplicable for photovoltaics or optoelectronics. However, if the RTA high temperature annealing is combined with a medium temperature inert gas post-annealing and a H{sub 2} passivation, luminescent Si NC fractions of up to 90% can be achieved with a significantly reduced thermal load. A new figure or merit, the relative dopant diffusion length, is introduced as a measure for the impact of a Si NC annealing procedure on doping profiles of device structures.

  15. The role of annealing temperature on the structural and magnetic consequences of Ta/PrFeB/Ta thin films processed by rapid thermal annealing

    NASA Astrophysics Data System (ADS)

    Ghasemi, Ali

    2016-04-01

    Ta/PrFeB/Ta thin films were deposited on CORNING 7059 by sputtering technique followed by rapid thermal annealing (RTA). The thickness of PrFeB was kept constant at 50 nm. The role of annealing temperature from 450 to 700 °C in a step of 50 °C for constant heating time of 60 s on the structural and magnetic consequences of thin films was studied by means of X-ray diffraction, field emission scanning electron microscopy, atomic force microscopy and vibrating sample magnetometer. The (00l) texture was almost fully developed at temperature of 650 °C and with an increase in temperature up to 700 °C the (105) peaks was also appeared in the patterns. The grains size and surface roughness of PrFeB films were increased by an increase in temperature. It was found that with an increase in temperature up to 500 °C the coercivity was developed and enhanced to 0.75 MA/m by further increasing of temperature to 650 °C. The maximum remanent-magnetization ratio and coercivity were obtained at temperature of 650 °C. The magnetization reversal process is accompanied by the combination of domain wall motion (DWM) and Stoner-Wohlfarth (S-W) rotation. However, for PrFeB films annealed at 550-700 °C it is closer to the S-W model than DWM modes.

  16. Rapid thermal processing of high-efficiency silicon solar cells with controlled in-situ annealing

    SciTech Connect

    Doshi, P.; Rohatgi, A.; Ropp, M.; Chen, Z.; Ruby, D.; Meier, D.L.

    1995-01-01

    Silicon solar cell efficiencies of 17.1%, 16.4%, 14.8%, and 14.9% have been achieved on FZ, Cz, multicrystalline (mc-Si), and dendritic web (DW) silicon, respectively, using simplified, cost-effective rapid thermal processing (RTP). These represent the highest reported efficiencies for solar cells processed with simultaneous front and back diffusion with no conventional high-temperature furnace steps. Appropriate diffusion temperature coupled with the added in-situ anneal resulted in suitable minority-carrier lifetime and diffusion profiles for high-efficiency cells. The cooling rate associated with the in-situ anneal can improve the lifetime and lower the reverse saturation current density (J{sub 0}), however, this effect is material and base resistivity specific. PECVD antireflection (AR) coatings provided low reflectance and efficient front surface and bulk defect passivation. Conventional cells fabricated on FZ silicon by furnace diffusions and oxidations gave an efficiency of 18.8% due to greater short wavelength response and lower J{sub 0}.

  17. Computer-enhanced video microscopy: digitally processed microscope images can be produced in real time.

    PubMed Central

    Walter, R J; Berns, M W

    1981-01-01

    Digital processing techniques can be used to greatly enhance the available information in an optical image. Although this technology has been routinely used in many fields for a number of years, little application of digital image-processing techniques have been made toward analysis and enhancement of the types of images seen most often by the research biologist. We describe here a computer-based video microscope system that is capable of performing extensive manipulation and enhancement of microscope images in real time. The types of manipulations possible with these techniques greatly surpass the enhancement capabilities of photographic or video techniques alone. The speed and flexibility of this system enables experimental manipulation of the microscopic specimen based on its live processed image. These features greatly extend the power and versatility of the light microscope. Images PMID:6947267

  18. Effects of thermal annealing process on the electrical properties of p{sup +}-Si/n-SiC heterojunctions

    SciTech Connect

    Liang, J. Nishida, S.; Shigekawa, N.; Arai, M.

    2014-04-21

    The effects of thermal annealing process on the interface in p{sup +}-Si/n-SiC heterojunctions fabricated by using surface-activated bonding are investigated. It is found by measuring their current-voltage (I-V) characteristics that the reverse-bias current and the ideality factor decreased to 2.98 × 10{sup −6} mA/cm{sup 2} and 1.03, respectively, by annealing the junctions at 1000 °C. Observation by using transmission electron microscopy indicates that an amorphous layer with a thickness of ∼6 nm is formed at the unannealed interface, which vanishes after annealing at 1000 °C. No structural defects at the interface are observed even after annealing at such a high temperature.

  19. Molecular Interdiffusion between Stacked Layers by Solution and Thermal Annealing Processes in Organic Light Emitting Devices.

    PubMed

    Ohisa, Satoru; Pu, Yong-Jin; Yamada, Norifumi L; Matsuba, Go; Kido, Junji

    2015-09-23

    In organic light emitting devices (OLEDs), interfacial structures between multilayers have large impacts on the characteristics of OLEDs. Herein, we succeeded in revealing the interdiffusion in solution processed and thermal annealed OLEDs by neutron reflectometry. We investigated interfaces between a polymer under layer and small molecules upper layer. The small molecules diffused into the swollen polymer layer during the interfacial formation by the solution process, but the polymer did not diffuse into the small molecules layer. At temperatures close to the glass transition temperatures of the materials, asymmetric molecular diffusion was observed. We elucidated the effects of the interdiffusion on the characteristics of OLEDs. Partially mixing the interface improved the current efficiencies due to suppressed triplet-polaron quenching at the interface. Controlling and understanding the interfacial structures of the miultilayers will be more important to improve the OLED characteristics. PMID:26331696

  20. Effect of Nano-Particle Addition on Grain Structure Evolution of Friction Stir-Processed Al 6061 During Postweld Annealing

    NASA Astrophysics Data System (ADS)

    Guo, Junfeng; Lee, Bing Yang; Du, Zhenglin; Bi, Guijun; Tan, Ming Jen; Wei, Jun

    2016-06-01

    The fabrication of nano-composites is challenging because uniform dispersion of nano-sized reinforcements in metallic substrate is difficult to achieve using powder metallurgy or liquid processing methods. In the present study, Al-based nano-composites reinforced with Al2O3 particles have been successfully fabricated using friction stir processing. The effects of nano-Al2O3 particle addition on grain structure evolution of friction stir-processed Al matrix during post-weld annealing were investigated. It was revealed that the pinning effect of Al2O3 particles retarded grain growth and completely prevented abnormal grain growth during postweld annealing at 470°C. However, abnormal grain growth can still occur when the composite material was annealed at 530°C. The mechanism involved in the grain structure evolution and the effect of nano-sized particle addition on the mechanical properties were discussed therein.

  1. Energy dependence of defects in a-Si:H solar cells during degradation and annealing processes

    SciTech Connect

    Caputo, D.; Lemmi, F.; Palma, F.

    1997-07-01

    In this work the authors report on the effect of current-induced degradation and annealing on p-i-n amorphous silicon solar cells. Current-voltage curves and capacitance measurements under forward bias have been used to monitor the current-induced changes as a function of time. They found that the recovery rate increases with the annealing current, while the stabilized value of efficiency decreases. Comparison of short circuit current and capacitance evolution suggests that defect kinetics in the electronic gap occurs in a different way during degradation and annealing. This behavior can be modeled assuming a faster annealing of defects closest to the extended band and a slower annealing of mid-gap defects.

  2. Rapid low-temperature processing of metal-oxide thin film transistors with combined far ultraviolet and thermal annealing

    SciTech Connect

    Leppäniemi, J. Ojanperä, K.; Kololuoma, T.; Huttunen, O.-H.; Majumdar, H.; Alastalo, A.; Dahl, J.; Tuominen, M.; Laukkanen, P.

    2014-09-15

    We propose a combined far ultraviolet (FUV) and thermal annealing method of metal-nitrate-based precursor solutions that allows efficient conversion of the precursor to metal-oxide semiconductor (indium zinc oxide, IZO, and indium oxide, In{sub 2}O{sub 3}) both at low-temperature and in short processing time. The combined annealing method enables a reduction of more than 100 °C in annealing temperature when compared to thermally annealed reference thin-film transistor (TFT) devices of similar performance. Amorphous IZO films annealed at 250 °C with FUV for 5 min yield enhancement-mode TFTs with saturation mobility of ∼1 cm{sup 2}/(V·s). Amorphous In{sub 2}O{sub 3} films annealed for 15 min with FUV at temperatures of 180 °C and 200 °C yield TFTs with low-hysteresis and saturation mobility of 3.2 cm{sup 2}/(V·s) and 7.5 cm{sup 2}/(V·s), respectively. The precursor condensation process is clarified with x-ray photoelectron spectroscopy measurements. Introducing the FUV irradiation at 160 nm expedites the condensation process via in situ hydroxyl radical generation that results in the rapid formation of a continuous metal-oxygen-metal structure in the film. The results of this paper are relevant in order to upscale printed electronics fabrication to production-scale roll-to-roll environments.

  3. [Role of microscopic fungi in the process of weathering of pegmatite deposit rocks and minerals].

    PubMed

    Avakian, Z A; Karavaiko, G I; Mel'nikova, E O; Krutsko, V S; Ostroushko, Iu I

    1981-01-01

    The object of this work was to study the effect of microscopic fungi isolated from the weathering zone of a pegmatite deposit on the transport of elements and the degradation of rocks and minerals. Regardless of the chemical composition of rocks and minerals, microscopic fungi accelerated the leaching of elements as compared to the purely chemical process. The extraction of Li, Si, Al and Fe under the action of microorganisms increased by factors of 1.4-1.7, 2.7-4.0, 5.0-8.7 and 4-18, respectively. In the case of chemical weathering, the extraction of elements occurred at a high rate only at the beginning; then the process either decelerated or stopped. The mechanism of action of microscopic fungi on rocks and minerals is discussed as well as the role of these microorganisms in the weathering of spodumene and the surrounding rocks, pegmatites an shales, which occurs in the zone of hypergenesis. PMID:7194415

  4. Development of a scanning nanopipette probe microscope for fine processing using atmospheric pressure plasma jet

    NASA Astrophysics Data System (ADS)

    Morimatsu, Daisuke; Sugimoto, Hiromitsu; Nakamura, Atsushi; Ogino, Akihisa; Nagatsu, Masaaki; Iwata, Futoshi

    2016-08-01

    We developed a novel technique for fine material processing based on a localized atmospheric-pressure plasma jet (APPJ) using a scanning probe microscope equipped with a nanopipette. Using a nanopipette — a tapered glass capillary with an aperture of sub-micrometer diameter — as a nozzle makes it possible to localize the discharge area of the APPJ for fine surface processing. The nanopipette can also be used as a probe for a scanning probe microscope operated with shear-force feedback control, which is capable of positioning the pipette edge in the vicinity of material surfaces for APPJ processing and imaging of the processed surface. Sub-micrometer holes and line patterns were successfully processed on a photoresist film. It was possible to control the size of the processed patterns by varying the applied pulse voltage and the distance between the pipette and the surface.

  5. Gamification in Science Education: Gamifying Learning of Microscopic Processes in the Laboratory

    ERIC Educational Resources Information Center

    Fleischmann, Katja; Ariel, Ellen

    2016-01-01

    Understanding and trouble-shooting microscopic processes involved in laboratory tests are often challenging for students in science education because of the inability to visualize the different steps and the various errors that may influence test outcome. The effectiveness of gamification or the use of game design elements and game-mechanics were…

  6. Effects of quenching, irradiation, and annealing processes on the radiation hardness of silica fiber cladding materials (I)

    NASA Astrophysics Data System (ADS)

    Wen, Jianxiang; Gong, Renxiang; Xiao, Zhongyin; Luo, Wenyun; Wu, Wenkai; Luo, Yanhua; Peng, Gang-ding; Pang, Fufei; Chen, Zhenyi; Wang, Tingyun

    2016-07-01

    Silica optical fiber cladding materials were experimentally treated by a series of processes. The treatments involved quenching, irradiation, followed by annealing and subsequent re-irradiation, and they were conducted in order to improve the radiation hardness. The microstructural properties of the treated materials were subsequently investigated. Following the treatment of the optical fiber cladding materials, the results from the electron spin resonance (ESR) analysis demonstrated that there was a significant decrease in the radiation-induced defect structures. The ESR signals became significantly weaker when the samples were annealed at 1000 °C in combination with re-irradiation. In addition, the microstructure changes within the silica optical fiber cladding material were also analyzed using Raman spectroscopy. The experimental results demonstrate that the Sisbnd Osbnd Si bending vibrations at ω3 = 800-820 cm-1 and ω4 = 1000-1200 cm-1 (with longitudinal optical (LO) and transverse optical (TO) splitting bands) were relatively unaffected by the quenching, irradiation, and annealing treatments. In particular, the annealing process resulted in the disappearance of the defect centers; however, the LO and TO modes at the ω3 and ω4 bands were relatively unchanged. With the additional support of the ESR test results, we can conclude that the combined treatment processes can significantly enhance the radiation hardness properties of the optical fiber cladding materials.

  7. Microscopic investigation of the magnetic saturation process for Co/Pt multilayers

    NASA Astrophysics Data System (ADS)

    Quach, Duy-Truong; Kim, Dong-Hyun; Lee, Kyung-Min; Jeong, Jong-Ryul; Pham, Duc-Thang

    2016-07-01

    We have systematically investigated the magnetic saturation process for Co/Pt multilayers with perpendicular magnetic anisotropy by using the first-order reversal-curve (FORC) technique. We find that even for a field that apparently is higher than the major-loop saturation field, some microscopically not-yet-annihilated domains still remain. The true saturation on a microscopic scale field is found to be about 1.5 to 2.5 times greater than the macroscopicall-determined majorloop saturation field. Not-yet-annihilated domains are observed to be exponentially reduced with respect to the applied magnetic field.

  8. Influence of film structure on the dewetting kinetics of thin polymer films in the solvent annealing process.

    PubMed

    Zhang, Huanhuan; Xu, Lin; Lai, Yuqing; Shi, Tongfei

    2016-06-28

    On a non-wetting solid substrate, the solvent annealing process of a thin polymer film includes the swelling process and the dewetting process. Owing to difficulties in the in situ analysis of the two processes simultaneously, a quantitative study on the solvent annealing process of thin polymer films on the non-wetting solid substrate is extremely rare. In this paper, we design an experimental method by combining spectroscopic ellipsometry with optical microscopy to achieve the simultaneous in situ study. Using this method, we investigate the influence of the structure of swollen film on its dewetting kinetics during the solvent annealing process. The results show that for a thin PS film with low Mw (Mw = 4.1 kg mol(-1)), acetone molecules can form an ultrathin enriched layer between the PS film and the solid substrate during the swelling process. The presence of the acetone enriched layer accounts for the exponential kinetic behavior in the case of a thin PS film with low Mw. However, the acetone enriched layer is not observed in the case of a thin PS film with high Mw (Mw = 400 kg mol(-1)) and the slippage effect of polymer chains is valid during the dewetting process. PMID:27254136

  9. Effects of annealing conditions on the dielectric properties of solution-processed Al2O3 layers for indium-zinc-tin-oxide thin-film transistors.

    PubMed

    Kim, Yong-Hoon; Kim, Kwang-Ho; Park, Sung Kyu

    2013-11-01

    In this paper, the effects of annealing conditions on the dielectric properties of solution-processed aluminum oxide (Al2O3) layers for indium-zinc-tin-oxide (IZTO) thin-film transistors (TFTs) have been investigated. The dielectric properties of Al2O3 layers such as leakage current density and dielectric strength were largely affected by their annealing conditions. In particular, oxygen partial pressure in rapid thermal annealing, and the temperature profile of hot plate annealing had profound effects on the dielectric properties. From a refractive index analysis, the enhanced dielectric properties of Al2O3 gate dielectrics can be attributed to higher film density depending on the annealing conditions. With the low-temperature-annealed Al2O3 gate dielectric at 350 degrees C, solution-processed IZTO TFTs with a field-effect mobility of approximately 2.2 cm2/Vs were successfully fabricated. PMID:24245333

  10. Annealing of chromium oxycarbide coatings deposited by plasma immersion ion processing (PIIP) for aluminum die casting

    NASA Astrophysics Data System (ADS)

    Peters, A. M.; He, X. M.; Trkula, M.; Nastasi, M.

    2001-04-01

    Chromium oxycarbide coatings have been investigated for use as non-wetting coatings for aluminum die casting. This paper examines Cr-C-O coating stability and non-wetability at elevated temperatures for extended periods. Coatings were deposited onto 304 stainless steel from chromium carbonyl [Cr(CO) 6] by plasma immersion ion processing. The coatings were annealed in air at an aluminum die casting temperature of 700°C up to 8 h. Coatings were analyzed using resonant ion backscattering spectroscopy, nanoindentation and pin-on-disk tribometry. Molten aluminum was used to determine coating wetting and contact angle. Results indicate that the surface oxide layer reaches a maximum thickness of 900 nm. Oxygen concentrations in the coatings increased from 24% to 34%, while the surface concentration rose to almost 45%. Hardness values ranged from 22.1 to 6.7 GPa, wear coefficients ranged from 21 to 8×10 -6 mm3/ Nm and contact angles ranged from 156° to 127°.

  11. Annealing process of F- and F+-centers in Al2O3 single crystal induced by fast neutrons irradiation

    NASA Astrophysics Data System (ADS)

    Izerrouken, M.; Djouadi, Y.; Zirour, H.

    2014-01-01

    F and F+ centers were produced in Al2O3 single crystal by fast neutrons (En > 1.2 MeV) irradiation at low fluence (4.4 × 1016 n cm-2). The evolution of defects intensity as a function of temperature and of time at 493, 623 and 823 K was investigated by UV-visible spectrophotometry technique. It can be concluded from the analysis of isochronal and isothermal annealing data, that the F- and F+-centers annealing process is complex. At low annealing temperature (<473 K), only F- to F+-center conversion process takes place. At higher temperature (>493 K) the annealing is due to the superposition of several mechanisms with different activation energies. According to our results, the activation energies needed for both F- and F+-centers elimination are 0.2, 0.3 and 0.03 eV for temperature range of 300-673 K, 673-873 K and >873 K, respectively.

  12. Development of a hydrogen-based annealing process for desulfurization of single crystalline, nickel-based superalloy. Final report

    SciTech Connect

    Smith, M.; Mickle, T.H.; Frazier, W.E.; Waldman, J.

    1994-11-05

    The presence of minor amounts of sulfur (1-10 ppm) in nickel-based superalloys has been associated with reduced oxidation resistance and premature spallation of protective coatings. A hydrogen annealing process has been developed by NAWCADWAR which effectively reduces the sulfur content of superalloys. The conditions which allow effective desulfurization are delineated. Diffusion of sulfur through the superalloy is found to be the rate controlling step for the process.

  13. Effects of a modular two-step ozone-water and annealing process on silicon carbide graphene

    SciTech Connect

    Webb, Matthew J. Lundstedt, Anna; Grennberg, Helena; Polley, Craig; Niu, Yuran; Zakharov, Alexei A.; Balasubramanian, Thiagarajan; Dirscherl, Kai; Burwell, Gregory; Guy, Owen J.; Palmgren, Pål; Yakimova, Rositsa

    2014-08-25

    By combining ozone and water, the effect of exposing epitaxial graphene on silicon carbide to an aggressive wet-chemical process has been evaluated after high temperature annealing in ultra high vacuum. The decomposition of ozone in water produces a number of oxidizing species, however, despite long exposure times to the aqueous-ozone environment, no graphene oxide was observed after the two-step process. The systems were comprehensively characterized before and after processing using Raman spectroscopy, core level photoemission spectroscopy, and angle resolved photoemission spectroscopy together with low energy electron diffraction, low energy electron microscopy, and atomic force microscopy. In spite of the chemical potential of the aqueous-ozone reaction environment, the graphene domains were largely unaffected raising the prospect of employing such simple chemical and annealing protocols to clean or prepare epitaxial graphene surfaces.

  14. The Role of Annealing Process in Ag-Based BaSnO3 Multilayer Thin Films.

    PubMed

    Wu, Muying; Yu, Shihui; He, Lin; Yang, Lei; Zhang, Weifeng

    2016-12-01

    The BaSnO3/Ag/BaSnO3 multilayer structure was designed and fabricated on a quartz glass by magnetron sputtering, followed by an annealing process at a temperature from 150 to 750 °C in air. In this paper, we investigated the influence of the annealing temperature on the structural, optical, and electrical properties of the multilayers and proposed the mechanisms of conduction and transmittance. The maximum value of the figure of merit of 31.8 × 10(-3) Ω(-1) was achieved for the BaSnO3/Ag/BaSnO3 multilayer thin films annealed at 150 °C, while the average optical transmittance in the visible ranges was >84 %, the resistivity was 5.71 × 10(-5) Ω cm, and the sheet resistance was 5.57 Ω/sq. When annealed at below 600 °C, the values of resistivity and transmittance of the multilayers were within an acceptable range (resistivity <5.0 × 10(-4) Ω cm, transmittance >80 %). The observed property of the multilayer film is suitable for the application of transparent conductive electrodes. PMID:27544775

  15. Efficiency enhancement in solution-processed organic small molecule: Fullerene solar cells via solvent vapor annealing

    NASA Astrophysics Data System (ADS)

    Miao, Jingsheng; Chen, Hui; Liu, Feng; Zhao, Baofeng; Hu, Lingyu; He, Zhicai; Wu, Hongbin

    2015-05-01

    We report highly efficient small molecule solar cells (SMSCs) by using dichloromethane solvent vapor annealing method. The resulted devices delivered a power conversion efficiency (PCE) of 8.3%, which is among the highest in SMSCs. Comparing to the control devices, the short circuit current (Jsc), fill factor, and PCE of solvent vapor annealed devices are significantly improved. Summarizing the results of optical absorption, film morphology, and charge carrier transporting properties, we see that the enhanced structure order and reduced size of phase separation are major reasons for the improved device performances, establishing a solid structure-property relationship. The solvent vapor annealing method can thus be a useful method in device fabrication to enhance performances of SMSCs.

  16. An array microscope for ultrarapid virtual slide processing and telepathology. Design, fabrication, and validation study.

    PubMed

    Weinstein, Ronald S; Descour, Michael R; Liang, Chen; Barker, Gail; Scott, Katherine M; Richter, Lynne; Krupinski, Elizabeth A; Bhattacharyya, Achyut K; Davis, John R; Graham, Anna R; Rennels, Margaret; Russum, William C; Goodall, James F; Zhou, Pixuan; Olszak, Artur G; Williams, Bruce H; Wyant, James C; Bartels, Peter H

    2004-11-01

    This paper describes the design and fabrication of a novel array microscope for the first ultrarapid virtual slide processor (DMetrix DX-40 digital slide scanner). The array microscope optics consists of a stack of three 80-element 10 x 8-lenslet arrays, constituting a "lenslet array ensemble." The lenslet array ensemble is positioned over a glass slide. Uniquely shaped lenses in each of the lenslet arrays, arranged perpendicular to the glass slide constitute a single "miniaturized microscope." A high-pixel-density image sensor is attached to the top of the lenslet array ensemble. In operation, the lenslet array ensemble is transported by a motorized mechanism relative to the long axis of a glass slide. Each of the 80 miniaturized microscopes has a lateral field of view of 250 microns. The microscopes of each row of the array are offset from the microscopes in other rows. Scanning a glass slide with the array microscope produces seamless two-dimensional image data of the entire slide, that is, a virtual slide. The optical system has a numerical aperture of N.A.= 0.65, scans slides at a rate of 3 mm per second, and accrues up to 3,000 images per second from each of the 80 miniaturized microscopes. In the ultrarapid virtual slide processing cycle, the time for image acquisition takes 58 seconds for a 2.25 cm2 tissue section. An automatic slide loader enables the scanner to process up to 40 slides per hour without operator intervention. Slide scanning and image processing are done concurrently so that post-scan processing is eliminated. A virtual slide can be viewed over the Internet immediately after the scanning is complete. A validation study compared the diagnostic accuracy of pathologist case readers using array microscopy (with images viewed as virtual slides) and conventional light microscopy. Four senior pathologists diagnosed 30 breast surgical pathology cases each using both imaging modes, but on separate occasions. Of 120 case reads by array microscopy

  17. Advanced processing of gallium nitride and gallium nitride-based devices: Ultra-high temperature annealing and implantation incorporation

    NASA Astrophysics Data System (ADS)

    Yu, Haijiang

    This dissertation is focused on three fields: ultra-high temperature annealing of GaN, activation of implanted GaN and the implantation incorporation into AlGaN/GaN HEMT processing, with an aim to increase the performance, manufacturability and reliability of AlGaN/GaN HEMTs. First, the ultra high temperature (around 1500°C) annealing of MOCVD grown GaN on sapphire has been studied, and a thermally induced threading dislocation (TD) motion and reaction are reported. Using a rapid thermal annealing (RTA) approach capable of heating 2 inch wafers to around 1500°C with 100 bar N2 over-pressure, evidence of dislocation motion was first observed in transmission electron microscopy (TEM) micrographs of both planar and patterned GaN films protected by an AIN capping layer. An associated decrease in x-ray rocking curve (XRC) full-width-half-maximum (FWHM) was also observed for both the symmetric and asymmetric scans. After annealing, the AIN capping layer remained intact, and optical measurements showed no degradation of the opto-electronic properties of the films. Then activation annealing of Si implants in MOCVD grown GaN has been studied for use in ohmic contacts. Si was implanted in semi-insulating GaN at 100 keV with doses from 5 x 1014 cm-2 to 1.5 x 1016 cm-2. Rapid thermal annealing at 1500°C with 100 bar N2 over-pressure was used for dopant activation, resulting in a minimum sheet resistance of 13.9 O/square for a dose of 7 x 1015 cm-2. Secondary ion mass spectroscopy measurements showed a post-activation broadening of the dopant concentration peak by 20 nm (at half the maximum), while X-Ray triple axis o-2theta scans indicated nearly complete implant damage recovery. Transfer length method measurements of the resistance of Ti/Al/Ni/Au contacts to activated GaN:Si (5 x 1015 cm-2 at 100 keV) indicated lowest contact resistances of 0.07 Omm and 0.02 Omm for as-deposited and subsequently annealed contacts, respectively. Finally, the incorporation of Si implantation

  18. Extended morphological processing: a practical method for automatic spot detection of biological markers from microscopic images

    PubMed Central

    2010-01-01

    Background A reliable extraction technique for resolving multiple spots in light or electron microscopic images is essential in investigations of the spatial distribution and dynamics of specific proteins inside cells and tissues. Currently, automatic spot extraction and characterization in complex microscopic images poses many challenges to conventional image processing methods. Results A new method to extract closely located, small target spots from biological images is proposed. This method starts with a simple but practical operation based on the extended morphological top-hat transformation to subtract an uneven background. The core of our novel approach is the following: first, the original image is rotated in an arbitrary direction and each rotated image is opened with a single straight line-segment structuring element. Second, the opened images are unified and then subtracted from the original image. To evaluate these procedures, model images of simulated spots with closely located targets were created and the efficacy of our method was compared to that of conventional morphological filtering methods. The results showed the better performance of our method. The spots of real microscope images can be quantified to confirm that the method is applicable in a given practice. Conclusions Our method achieved effective spot extraction under various image conditions, including aggregated target spots, poor signal-to-noise ratio, and large variations in the background intensity. Furthermore, it has no restrictions with respect to the shape of the extracted spots. The features of our method allow its broad application in biological and biomedical image information analysis. PMID:20615231

  19. Tuning surface properties of amino-functionalized silica for metal nanoparticle loading: The vital role of an annealing process

    SciTech Connect

    Pei, Yuchen; Xiao, Chaoxian; Goh, Tian -Wei; Zhang, Qianhui; Goes, Shannon; Sun, Weijun; Huang, Wenyu

    2015-10-20

    Metal nanoparticles (NPs) loaded on oxides have been widely used as multifunctional nanomaterials in various fields such as optical imaging, sensors, and heterogeneous catalysis. However, the deposition of metal NPs on oxide supports with high efficiency and homogeneous dispersion still remains elusive, especially when silica is used as the support. Amino-functionalization of silica can improve loading efficiency, but metal NPs often aggregate on the surface. Herein, we report that a facial annealing of amino-functionalized silica can significantly improve the dispersion and enhance the loading efficiency of various metal NPs, such as Pt, Rh, and Ru, on the silica surface. A series of characterization techniques, such as diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), Zeta potential analysis, UV–Vis spectroscopy, thermogravimetric analysis coupled with infrared analysis (TGA–IR), and nitrogen physisorption, were employed to study the changes of surface properties of the amino-functionalized silica before and after annealing. We found that the annealed amino-functionalized silica surface has more cross-linked silanol groups and relatively lesser amount of amino groups, and less positively charges, which could be the key to the uniform deposition of metal NPs during the loading process. Lastly, these results could contribute to the preparation of metal/oxide hybrid NPs for the applications that require uniform dispersion.

  20. Tuning surface properties of amino-functionalized silica for metal nanoparticle loading: The vital role of an annealing process

    DOE PAGESBeta

    Pei, Yuchen; Xiao, Chaoxian; Goh, Tian -Wei; Zhang, Qianhui; Goes, Shannon; Sun, Weijun; Huang, Wenyu

    2015-10-20

    Metal nanoparticles (NPs) loaded on oxides have been widely used as multifunctional nanomaterials in various fields such as optical imaging, sensors, and heterogeneous catalysis. However, the deposition of metal NPs on oxide supports with high efficiency and homogeneous dispersion still remains elusive, especially when silica is used as the support. Amino-functionalization of silica can improve loading efficiency, but metal NPs often aggregate on the surface. Herein, we report that a facial annealing of amino-functionalized silica can significantly improve the dispersion and enhance the loading efficiency of various metal NPs, such as Pt, Rh, and Ru, on the silica surface. Amore » series of characterization techniques, such as diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), Zeta potential analysis, UV–Vis spectroscopy, thermogravimetric analysis coupled with infrared analysis (TGA–IR), and nitrogen physisorption, were employed to study the changes of surface properties of the amino-functionalized silica before and after annealing. We found that the annealed amino-functionalized silica surface has more cross-linked silanol groups and relatively lesser amount of amino groups, and less positively charges, which could be the key to the uniform deposition of metal NPs during the loading process. Lastly, these results could contribute to the preparation of metal/oxide hybrid NPs for the applications that require uniform dispersion.« less

  1. Tuning surface properties of amino-functionalized silica for metal nanoparticle loading: The vital role of an annealing process

    NASA Astrophysics Data System (ADS)

    Pei, Yuchen; Xiao, Chaoxian; Goh, Tian-Wei; Zhang, Qianhui; Goes, Shannon; Sun, Weijun; Huang, Wenyu

    2016-06-01

    Metal nanoparticles (NPs) loaded on oxides have been widely used as multifunctional nanomaterials in various fields such as optical imaging, sensors, and heterogeneous catalysis. However, the deposition of metal NPs on oxide supports with high efficiency and homogeneous dispersion still remains elusive, especially when silica is used as the support. Amino-functionalization of silica can improve loading efficiency, but metal NPs often aggregate on the surface. Herein, we report that a facial annealing of amino-functionalized silica can significantly improve the dispersion and enhance the loading efficiency of various metal NPs, such as Pt, Rh, and Ru, on the silica surface. A series of characterization techniques, such as diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), Zeta potential analysis, UV-Vis spectroscopy, thermogravimetric analysis coupled with infrared analysis (TGA-IR), and nitrogen physisorption, were employed to study the changes of surface properties of the amino-functionalized silica before and after annealing. We found that the annealed amino-functionalized silica surface has more cross-linked silanol groups and relatively lesser amount of amino groups, and less positively charges, which could be the key to the uniform deposition of metal NPs during the loading process. These results could contribute to the preparation of metal/oxide hybrid NPs for the applications that require uniform dispersion.

  2. Selective synthesis of boron nitride nanotubes by self-propagation high-temperature synthesis and annealing process

    SciTech Connect

    Wang Jilin; Zhang Laiping; Zhao Guowei; Gu Yunle; Zhang Zhanhui; Zhang Fang; Wang Weimin

    2011-09-15

    Four types of BN nanotubes are selectively synthesized by annealing porous precursor in flowing NH{sub 3} and NH{sub 3}/H{sub 2} atmosphere at temperature ranging from 1000 to 1200 deg. C in a vertical furnace. The as-synthesized BN nanotubes, including cylinder, wave-like, bamboo-like and bubble-chain, are characterized by XRD, FTIR, Raman, SEM, TEM and HRTEM. Three phenomenological growth models are proposed to interpret growth scenario and structure features of the four types of BN nanotubes. Selectivity of nanotubes formation is estimated as approximately 80-95%. The precursor containing B, Mg, Fe and O prepared by self-propagation high-temperature synthesis (SHS) method plays a key role in selective synthesis of the as-synthesized BN nanotubes. Chemical reactions are also discussed. - Graphical Abstract: Four types of BN nanotubes are selectively synthesized by annealing porous precursor prepared by self-propagation high-temperature synthesis. Three phenomenological growth models are proposed to reveal growth scenario and characteristics of the as-synthesized BN nanotubes. Highlights: > Four types of BN nanotubes are selectively synthesized by annealing porous precursor. > Selectivity of BN nanotubes formation is estimated as approximately 80-95 wt%. > Three growth models are proposed to interpret growth of the as-synthesized BN nanotubes. > The precursor prepared by SHS method plays a key role in selective synthesis process.

  3. Highly efficient low-bandgap polymer solar cells with solution-processed and annealing-free phosphomolybdic acid as hole-transport layers.

    PubMed

    Jia, Xu; Shen, Liang; Yao, Mengnan; Liu, Yan; Yu, Wenjuan; Guo, Wenbin; Ruan, Shengping

    2015-03-11

    We demonstrate a novel solution-processed method to fabricate a stable anode buffer layer without any annealing process. As we know, buffer layers in polymer solar cells (PSCs) are always prepared by the traditional high-vacuum thermal evaporation or annealing-treated spin-coating methods, but the fabricating processes are complicated and time-consuming. Here, a solution method without any annealing to fabricate phosphomolybdic acid (PMA) as anode buffers is presented, which brings an obvious improvement of power conversion efficiency (PCE) from 1.75% to 6.57% by optimizing the PMA concentrations and interface pretreatment with device structure shown as ITO/TiO2/PCDTBT:PC70BM/PMA/Ag. The improvement is ascribed to the fine energy-level matching and perfect surface modification. This annealing-free method greatly simplifies the device fabrication process and supplies a wide way to achieve a large area fabrication for PSCs. PMID:25695125

  4. The morphometric analysis and recognition an amyloid plaque in microscope images by computer image processing.

    PubMed

    Grams, A; Liberski, P P; Sobów, T; Napieralska, M; Zubert, M; Napieralski, A

    2000-01-01

    This paper presents an approach of the two-dimensional image processing application in recognition of amyloid plaque in microscope images of the brain tissues. The authors propose to create universal amyloid plaque computer pattern and special multivariate image segmentation techniques based on collected images and statistical information. This recognition image procedure is divided into 3-dimensional statistical colour and morphological shape identifications. The developed computer system will collect and store image data and exchange them by network with other collaborated systems. PMID:11693723

  5. Effects of Annealing Process on the Formability of Friction Stir Welded Al-Li Alloy 2195 Plates

    NASA Technical Reports Server (NTRS)

    Chen, Po-Shou; Bradford, Vann; Russell, Carolyn

    2011-01-01

    Large rocket cryogenic tank domes have typically been fabricated using Al-Cu based alloys like Al-Cu alloy 2219. The use of aluminum-lithium based alloys for rocket fuel tank domes can reduce weight because aluminum-lithium alloys have lower density and higher strength than Al-Cu alloy 2219. However, Al-Li alloys have rarely been used to fabricate rocket fuel tank domes because of the inherent low formability characteristic that make them susceptible to cracking during the forming operations. The ability to form metal by stretch forming or spin forming without excessive thinning or necking depends on the strain hardening exponent "n". The stain hardening exponent is a measure of how rapidly a metal becomes stronger and harder. A high strain hardening exponent is beneficial to a material's ability to uniformly distribute the imposed strain. Marshall Space Flight Center has developed a novel annealing process that can achieve a work hardening exponent on the order of 0.27 to 0.29, which is approximately 50% higher than what is typically obtained for Al-Li alloys using the conventional method. The strain hardening exponent of the Al-Li alloy plates or blanks heat treated using the conventional method is typically on the order of 0.17 to 0.19. The effects of this novel annealing process on the formability of friction stir welded Al-Li alloy blanks are being studied at Marshall Space Flight Center. The formability ratings will be generated using the strain hardening exponent, strain rate sensitivity and forming range. The effects of forming temperature on the formability will also be studied. The objective of this work is to study the deformation behavior of the friction stir welded Al-Li alloy 2195 blank and determine the formability enhancement by the new annealing process.

  6. Fabrication of Graphene Directly on SiO2 without Transfer Processes by Annealing Sputtered Amorphous Carbon

    NASA Astrophysics Data System (ADS)

    Sato, Motonobu; Inukai, Manabu; Ikenaga, Eiji; Muro, Takayuki; Ogawa, Shuichi; Takakuwa, Yuji; Nakano, Haruhisa; Kawabata, Akio; Nihei, Mizuhisa; Yokoyama, Naoki

    2012-04-01

    We fabricated multilayer graphene directly on SiO2 by annealing sputtered amorphous carbon with a catalyst - a simple non-chemical vapor deposition method - without the use of complicated transfer processes. Structural analysis revealed that the graphene sheets formed an epitaxial structure aligned to the Co(111) surface between the Co catalyst and SiO2 dielectric. In the multilayer graphene, a resistivity of approximately 500 µΩ cm was obtained, which is one order of magnitude higher than that of highly oriented pyrolytic graphite.

  7. Facile Routes To Improve Performance of Solution-Processed Amorphous Metal Oxide Thin Film Transistors by Water Vapor Annealing.

    PubMed

    Park, Won-Tae; Son, Inyoung; Park, Hyun-Woo; Chung, Kwun-Bum; Xu, Yong; Lee, Taegweon; Noh, Yong-Young

    2015-06-24

    Here, we report on a simple and high-rate oxidization method for producing solution-based compound mixtures of indium zinc oxide (IZO) and indium gallium zinc oxide (IGZO) metal-oxide semiconductors (MOS) for thin-film transistor (TFT) applications. One of the issues for solution-based MOS fabrication is how to sufficiently oxidize the precursor in order to achieve high performance. As the oxidation rate of solution processing is lower than vacuum-based deposition such as sputtering, devices using solution-processed MOS exhibit relatively poorer performance. Therefore, we propose a method to prepare the metal-oxide precursor upon exposure to saturated water vapor in a closed volume for increasing the oxidization efficiency without requiring additional oxidizing agent. We found that the hydroxide rate of the MOS film exposed to water vapor is lower than when unexposed (≤18%). Hence, we successfully fabricated oxide TFTs with high electron mobility (27.9 cm(2)/V·s) and established a rapid process (annealing at 400 °C for 5 min) that is much shorter than the conventional as-deposited long-duration annealing (at 400 °C for 1 h) whose corresponding mobility is even lower (19.2 cm(2)/V·s). PMID:26043206

  8. Electron microscopic time-lapse visualization of surface pore filtration on particulate matter trapping process.

    PubMed

    Sanui, Ryoko; Hanamura, Katsunori

    2016-09-01

    A scanning electron microscope (SEM) was used to dynamically visualize the particulate matter (PM) trapping process on diesel particulate filter (DPF) walls at a micro scale as 'time-lapse' images corresponding to the increase in pressure drop simultaneously measured through the DPF. This visualization and pressure drop measurement led to the conclusion that the PM trapping in surface pores was driven by PM bridging and stacking at constricted areas in porous channels. This caused a drastic increase in the pressure drop during PM accumulation at the beginning of the PM trapping process. The relationship between the porous structure of the DPF and the depth of the surface pore was investigated in terms of the porosity distribution and PM penetration depth near the wall surface with respect to depth. The pressure drop calculated with an assumed surface pore depth showed a good correspondence to the measured pressure drop. PMID:26923765

  9. Macroscopic and microscopic deformation and failure processes that control composite toughness

    SciTech Connect

    Morgan, R.J.; Pruneda, C.O.

    1985-02-12

    Stress-optical microscopy and fracture topography studies of a variety of fibrous composites are presented and discussed in terms of the composite macroscopic and microscopic deformation and failure processes. Composite toughening mechanisms associated with the fiber failure processes and fiber-matrix interfacial strength are discussed. Molecular flow in the composite matrix, which enhances composite toughness, occurs either in the form of macroscopic homogeneous plastic flow or inhomogeneously in the form of crazing or shear banding. The physical parameters that control the toughening mechanisms in epoxy, thermoplastic and polyimide composite matrices are discussed. Effects of service environment exposure on the elimination of these toughening mechanisms which results in composite embrittlement are also considered.

  10. Laser apparatus and method for microscopic and spectroscopic analysis and processing of biological cells

    DOEpatents

    Gourley, P.L.; Gourley, M.F.

    1997-03-04

    An apparatus and method are disclosed for microscopic and spectroscopic analysis and processing of biological cells. The apparatus comprises a laser having an analysis region within the laser cavity for containing one or more biological cells to be analyzed. The presence of a cell within the analysis region in superposition with an activated portion of a gain medium of the laser acts to encode information about the cell upon the laser beam, the cell information being recoverable by an analysis means that preferably includes an array photodetector such as a CCD camera and a spectrometer. The apparatus and method may be used to analyze biomedical cells including blood cells and the like, and may include processing means for manipulating, sorting, or eradicating cells after analysis. 20 figs.

  11. Laser apparatus and method for microscopic and spectroscopic analysis and processing of biological cells

    DOEpatents

    Gourley, Paul L.; Gourley, Mark F.

    1997-01-01

    An apparatus and method for microscopic and spectroscopic analysis and processing of biological cells. The apparatus comprises a laser having an analysis region within the laser cavity for containing one or more biological cells to be analyzed. The presence of a cell within the analysis region in superposition with an activated portion of a gain medium of the laser acts to encode information about the cell upon the laser beam, the cell information being recoverable by an analysis means that preferably includes an array photodetector such as a CCD camera and a spectrometer. The apparatus and method may be used to analyze biomedical cells including blood cells and the like, and may include processing means for manipulating, sorting, or eradicating cells after analysis thereof.

  12. An image processing approach to analyze morphological features of microscopic images of muscle fibers

    PubMed Central

    Comin, Cesar Henrique; Xu, Xiaoyin; Wang, Yaming; da Fontoura Costa, Luciano; Yang, Zhong

    2016-01-01

    We present an image processing approach to automatically analyze duo-channel microscopic images of muscular fiber nuclei and cytoplasm. Nuclei and cytoplasm play a critical role in determining the health and functioning of muscular fibers as changes of nuclei and cytoplasm manifest in many diseases such as muscular dystrophy and hypertrophy. Quantitative evaluation of muscle fiber nuclei and cytoplasm thus is of great importance to researchers in musculoskeletal studies. The proposed computational approach consists of steps of image processing to segment and delineate cytoplasm and identify nuclei in two-channel images. Morphological operations like skeletonization is applied to extract the length of cytoplasm for quantification. We tested the approach on real images and found that it can achieve high accuracy, objectivity, and robustness. PMID:25124286

  13. Effect of excimer laser annealing on a-InGaZnO thin-film transistors passivated by solution-processed hybrid passivation layers

    NASA Astrophysics Data System (ADS)

    Bermundo, Juan Paolo; Ishikawa, Yasuaki; Fujii, Mami N.; Nonaka, Toshiaki; Ishihara, Ryoichi; Ikenoue, Hiroshi; Uraoka, Yukiharu

    2016-01-01

    We demonstrate the use of excimer laser annealing (ELA) as a low temperature annealing alternative to anneal amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs) passivated by a solution-processed hybrid passivation layer. Usually, a-IGZO is annealed using thermal annealing at high temperatures of up to 400 °C. As an alternative to high temperature thermal annealing, two types of ELA, XeCl (308 nm) and KrF (248 nm) ELA, are introduced. Both ELA types enhanced the electrical characteristics of a-IGZO TFTs leading to a mobility improvement of ~13 cm2 V-1 s-1 and small threshold voltage which varied from ~0-3 V. Furthermore, two-dimensional heat simulation using COMSOL Multiphysics was used to identify possible degradation sites, analyse laser heat localization, and confirm that the substrate temperature is below 50 °C. The two-dimensional heat simulation showed that the substrate temperature remained at very low temperatures, less than 30 °C, during ELA. This implies that any flexible material can be used as the substrate. These results demonstrate the large potential of ELA as a low temperature annealing alternative for already-passivated a-IGZO TFTs.

  14. Measuring microscopic evolution processes of complex networks based on empirical data

    NASA Astrophysics Data System (ADS)

    Chi, Liping

    2015-04-01

    Aiming at understanding the microscopic mechanism of complex systems in real world, we perform the measurement that characterizes the evolution properties on two empirical data sets. In the Autonomous Systems Internet data, the network size keeps growing although the system suffers a high rate of node deletion (r = 0.4) and link deletion (q = 0.81). However, the average degree keeps almost unchanged during the whole time range. At each time step the external links attached to a new node are about c = 1.1 and the internal links added between existing nodes are approximately m = 8. For the Scientific Collaboration data, it is a cumulated result of all the authors from 1893 up to the considered year. There is no deletion of nodes and links, r = q = 0. The external and internal links at each time step are c = 1.04 and m = 0, correspondingly. The exponents of degree distribution p(k) ∼ k-γ of these two empirical datasets γdata are in good agreement with that obtained theoretically γtheory. The results indicate that these evolution quantities may provide an insight into capturing the microscopic dynamical processes that govern the network topology.

  15. Reduction of the interfacial trap density of indium-oxide thin film transistors by incorporation of hafnium and annealing process

    SciTech Connect

    Lin, Meng-Fang E-mail: TSUKAGOSHI.Kazuhito@nims.go.jp; Gao, Xu; Mitoma, Nobuhiko; Kizu, Takio; Ou-Yang, Wei; Tsukagoshi, Kazuhito E-mail: TSUKAGOSHI.Kazuhito@nims.go.jp; Aikawa, Shinya; Nabatame, Toshihide

    2015-01-15

    The stable operation of transistors under a positive bias stress (PBS) is achieved using Hf incorporated into InO{sub x}-based thin films processed at relatively low temperatures (150 to 250 °C). The mobilities of the Hf-InO{sub x} thin-film transistors (TFTs) are higher than 8 cm{sup 2}/Vs. The TFTs not only have negligible degradation in the mobility and a small shift in the threshold voltage under PBS for 60 h, but they are also thermally stable at 85 °C in air, without the need for a passivation layer. The Hf-InO{sub x} TFT can be stable even annealed at 150 °C for positive bias temperature stability (PBTS). A higher stability is achieved by annealing the TFTs at 250 °C, originating from a reduction in the trap density at the Hf-InO{sub x}/gate insulator interface. The knowledge obtained here will aid in the realization of stable TFTs processed at low temperatures.

  16. Non-thermal alloyed ohmic contact process of GaN-based HEMTs by pulsed laser annealing

    NASA Astrophysics Data System (ADS)

    Tzou, An-Jye; Hsieh, Dan-Hua; Chen, Szu-Hung; Li, Zhen-Yu; Chang, Chun-Yen; Kuo, Hao-Chung

    2016-05-01

    We have demonstrated Si implantation incorporation into GaN HEMTs with a non-alloyed ohmic contact process. We optimized the power density of pulsed laser annealing to activate implanted Si dopants without a thermal metallization process. The experimental results show that the GaN surface will be reformed under the high power density of the illumination conditions. It provides a smooth surface for following contact engineering and leads to comparable contact resistance. The transmission line model (TLM) measurement shows a lower contact resistance to 6.8 × 10-7 Ω · cm2 via non-alloyed contact technology with significantly improved surface morphology of the contact metals. DC measurement of HEMTs shows better current and on-resistance. The on-resistance could be decreased from 2.18 to 1.74 mΩ-cm2 as we produce a lower contact resistance. Pulsed laser annealing also results in lower gate leakage and smaller dispersion under a pulse I-V measurement, which implies that the density of the surface state is improved.

  17. Reduction of the interfacial trap density of indium-oxide thin film transistors by incorporation of hafnium and annealing process

    NASA Astrophysics Data System (ADS)

    Lin, Meng-Fang; Gao, Xu; Mitoma, Nobuhiko; Kizu, Takio; Ou-Yang, Wei; Aikawa, Shinya; Nabatame, Toshihide; Tsukagoshi, Kazuhito

    2015-01-01

    The stable operation of transistors under a positive bias stress (PBS) is achieved using Hf incorporated into InOx-based thin films processed at relatively low temperatures (150 to 250 °C). The mobilities of the Hf-InOx thin-film transistors (TFTs) are higher than 8 cm2/Vs. The TFTs not only have negligible degradation in the mobility and a small shift in the threshold voltage under PBS for 60 h, but they are also thermally stable at 85 °C in air, without the need for a passivation layer. The Hf-InOx TFT can be stable even annealed at 150 °C for positive bias temperature stability (PBTS). A higher stability is achieved by annealing the TFTs at 250 °C, originating from a reduction in the trap density at the Hf-InOx/gate insulator interface. The knowledge obtained here will aid in the realization of stable TFTs processed at low temperatures.

  18. Bridging Oriented Copper Nanowire-Graphene Composites for Solution-Processable, Annealing-Free, and Air-Stable Flexible Electrodes.

    PubMed

    Zhang, Wang; Yin, Zhenxing; Chun, Alvin; Yoo, Jeeyoung; Kim, Youn Sang; Piao, Yuanzhe

    2016-01-27

    One-dimensional flexible metallic nanowires (NWs) are of considerable interest for next-generation wearable devices. The unavoidable challenge for a wearable electrode is the assurance of high conductivity, flexibility, and durability with economically feasible materials and simple manufacturing processes. Here, we use a straightforward solvothermal method to prepare a flexible conductive material that contains reduced graphene oxide (RGO) nanosheets bridging oriented copper NWs. The GO-assistance route can successfully meet the criteria listed above and help the composite films maintain high conductivity and durable flexibility without any extra treatment, such as annealing or acid processes. The composite film exhibits a high electrical performance (0.808 Ω·sq(-1)) without considerable change over 30 days under ambient conditions. Moreover, the Cu NW-RGO composites can be deposited on polyester cloth as a lightweight wearable electrode with high durability and simple processability and are very promising for a wide variety of electronic devices. PMID:26720592

  19. Microscopic tubes in igneous rocks

    NASA Technical Reports Server (NTRS)

    Richter, D.; Simmons, G.

    1977-01-01

    Microscopic tubes have been observed in several igneous rocks and may be quite common. They occur in single crystals and have either elliptical or circular cross-sections 1 to 5 microns in diameter and are ten to hundreds of microns long. Microtubes may be hollow or partially or completely filled with another phase, but are distinct from acicular crystals of accessory minerals such as rutile. Microtubes can form by at least three processes: (1) the partial annealing of microcracks, (2) the natural etching of dislocations, or (3) the primary inclusion of fluid material during crystal growth.

  20. Microscopic study of a ligand induced electroless plating process onto polymers.

    PubMed

    Garcia, Alexandre; Berthelot, Thomas; Viel, Pascal; Polesel-Maris, Jérôme; Palacin, Serge

    2010-11-01

    The ligand induced electroless plating (LIEP) process was recently developed and thoroughly demonstrated with one of the most used polymers for plating processes: acrylonitrile-butadiene-styrene (ABS). This generic process is based, thanks to the use of diazonium salts as precursors, on the covalent grafting of a thin layer of poly(acrylic acid) (PAA) acting as ligand for metallic salts onto pristine polymer surfaces. This strategy takes advantage of the PAA ion exchange properties. Indeed, carboxylate groups contained in PAA allow one to complex copper ions which are eventually reduced and used as catalysts of the metallic deposition. Essentially based on ABS, ABS-PC (ABS-polycarbonate) and PA (polyamide) substrates, the present paper focuses on the role of the polymer substrate and the relationships between the macroscopic properties and microscopic characterizations such as infrared (IR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and scanning electron microscopy (SEM). The adhesion strength of the metallic layer deposited via that LIEP process with the bulk polymer substrates was successfully compared with the adhesion of similar copper films deposited by the usual process based on chromic acid etching and palladium-based seed layer, by measuring the T-peel adhesion strength, and by carrying out the common industrial scotch tape test. Lastly, the electrical properties of the deposited layer were studied thanks to a four-point probe and scanning tunneling microscopy (STM) measurements. PMID:21053943

  1. Microscopic Approaches to Decomposition and Burning Processes of a Micro Plastic Resin Particle under Abrupt Heating

    NASA Astrophysics Data System (ADS)

    Ohiwa, Norio; Ishino, Yojiro; Yamamoto, Atsunori; Yamakita, Ryuji

    To elucidate the possibility and availability of thermal recycling of waste plastic resin from a basic and microscopic viewpoint, a series of abrupt heating processes of a spherical micro plastic particle having a diameter of about 200 μm is observed, when it is abruptly exposed to hot oxidizing combustion gas. Three ingenious devices are introduced and two typical plastic resins of polyethylene terephthalate and polyethylene are used. In this paper the dependency of internal and external appearances of residual plastic embers on the heating time and the ingredients of plastic resins is optically analyzed, along with appearances of internal micro bubbling, multiple micro explosions and jets, and micro diffusion flames during abrupt heating. Based on temporal variations of the surface area of a micro plastic particle, the apparent burning rate constant is also evaluated and compared with those of well-known volatile liquid fuels.

  2. Gate-first GaN MOSFET based on dry-etching-assisted non-annealing ohmic process

    NASA Astrophysics Data System (ADS)

    Wang, Qingpeng; Jiang, Ying; Zhang, Jiaqi; Li, Liuan; Kawaharada, Kazuya; Wang, Dejun; Ao, Jin-Ping

    2015-04-01

    We report on a gate-first GaN metal-oxide-semiconductor field-effect transistor (MOSFET) based on a non-annealing ohmic process. The device was formed on an n+-GaN (30 nm, 1 × 1019 cm-3)/semi-insulating GaN wafer. The source and drain (Ti/Al/Ti/Au) were deposited after the contact region was treated using an inductively coupled plasma (ICP) dry etching system. Ohmic contact with a contact resistance of 0.48 Ω mm was realized at room temperature. A device fabricated by a gate-first process shows good pinch-off characteristics and a maximum field-effect mobility of 163.8 cm2 V-1 s-1.

  3. Flow rate distribution and effect of convection and radiation heat transfer on the temperature profile during a coil annealing process

    NASA Astrophysics Data System (ADS)

    Haouam, A.; Bigerelle, M.

    2015-02-01

    Determining the temperature of several steel coils, heated in a furnace with a controlled hydrogen environment is important in an annealing process. Temperatures must be defined during heat treatment in order to guarantee metallurgical properties and acceptable reduced residual stresses. In this paper we approach hydrogen flow characteristics in the furnace and through a set of coils using an annealing non-differential model. Fluid flow is schematized as a pipe network solved by the Hardy Cross method to obtain pressure drops across the various gas flow segments. A comparison is made between measured and simulated results, confirming the adequacy of adopted assumptions and the validity of proposed model. Convective and radiative exchanges between the furnace and the coils are calculated by a discretization using the finite differences method. The convection coefficients are estimated and introduced into the boundary conditions around the coil to obtain the temperature distribution in the coils and in the covering bell. Finally, heat exchanges by convection and radiation are estimated by this model and the modeling errors are <8 °C.

  4. Evaluation of a gate-first process for AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistors with low ohmic annealing temperature

    NASA Astrophysics Data System (ADS)

    Liuan, Li; Jiaqi, Zhang; Yang, Liu; Jin-Ping, Ao

    2016-03-01

    In this paper, TiN/AlOx gated AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistors (MOS-HFETs) were fabricated for gate-first process evaluation. By employing a low temperature ohmic process, ohmic contact can be obtained by annealing at 600 °C with the contact resistance approximately 1.6 Ω·mm. The ohmic annealing process also acts as a post-deposition annealing on the oxide film, resulting in good device performance. Those results demonstrated that the TiN/AlOx gated MOS-HFETs with low temperature ohmic process can be applied for self-aligned gate AlGaN/GaN MOS-HFETs. Project supported by the International Science and Technology Collaboration Program of China (Grant No. 2012DFG52260).

  5. Microscopic processes ruling the bioavailability of Zn to roots of Euphorbia pithyusa L. pioneer plant.

    PubMed

    Medas, Daniela; De Giudici, Giovanni; Casu, Maria Antonietta; Musu, Elodia; Gianoncelli, Alessandra; Iadecola, Antonella; Meneghini, Carlo; Tamburini, Elena; Sprocati, Anna Rosa; Turnau, Katarzyna; Lattanzi, Pierfranco

    2015-02-01

    Euphorbia pithyusa L. was used in a plant growth-promoting assisted field trial experiment. To unravel the microscopic processes at the interface, thin slices of E. pithyusa roots were investigated by micro-X-ray fluorescence mapping. Roots and rhizosphere materials were examined by X-ray absorption spectroscopy at the Zn K-edge, X-ray diffraction, and scanning electron microscopy. Results indicate some features common to all the investigated samples. (i) In the rhizosphere of E. pithyusa, Zn was found to exist in different phases. (ii) Si and Al are mainly concentrated in a rim at the epidermis of the roots. (iii) Zn is mostly stored in root epidermis and does not appear to be coordinated to organic molecules but mainly occurs in mineral phases such as Zn silicates. We interpreted that roots of E. pithyusa significantly promote mineral evolution in the rhizosphere. Concomitantly, the plant uses Si and Al extracted by soil minerals to build a biomineralization rim, which can capture Zn. This Zn silicate biomineralization has relevant implications for phytoremediation techniques and for further biotechnology development, which can be better designed and developed after specific knowledge of molecular processes ruling mineral evolution and biomineralization processes has been gained. PMID:25568986

  6. The microscopic Z-pinch process of current-carrying rarefied deuterium plasma shell

    NASA Astrophysics Data System (ADS)

    Ning, Cheng; Feng, Zhixing; Xue, Chuang; Li, Baiwen

    2015-02-01

    For insight into the microscopic mechanism of Z-pinch dynamic processes, a code of two-dimensional particle-in-cell (PIC) simulation has been developed in cylindrical coordinates. In principle, the Z-pinch of current-carrying rarefied deuterium plasma shell has been simulated by means of this code. Many results related to the microscopic processes of the Z-pinch are obtained. They include the spatio-temporal distributions of electromagnetic field, current density, forces experienced by the ions and electrons, positions and energy distributions of particles, and trailing mass and current. In radial direction, the electric and magnetic forces exerted on the electrons are comparable in magnitude, while the forces exerted on the ions are mainly the electric forces. So in the Z-pinch process, the electrons are first accelerated in Z direction and get higher velocities; then, they are driven inwards to the axis at the same time by the radial magnetic forces (i.e., Lorentz forces) of them. That causes the separations between the electrons and ions because the ion mass is much larger than the electron's, and in turn a strong electrostatic field is produced. The produced electrostatic field attracts the ions to move towards the electrons. When the electrons are driven along the radial direction to arrive at the axis, they shortly move inversely due to the static repellency among them and their tiny mass, while the ions continue to move inertially inwards, and later get into stagnation, and finally scatter outwards. Near the stagnation, the energies of the deuterium ions mostly range from 0.3 to 6 keV, while the electron energies are mostly from 5 to 35 keV. The radial components, which can contribute to the pinched plasma temperature, of the most probable energies of electron and ion at the stagnation are comparable to the Bennett equilibrium temperature (about 1 keV), and also to the highest temperatures of electron and ion obtained in one dimensional radiation

  7. The microscopic Z-pinch process of current-carrying rarefied deuterium plasma shell

    SciTech Connect

    Ning, Cheng; Xue, Chuang; Li, Baiwen; Feng, Zhixing

    2015-02-15

    For insight into the microscopic mechanism of Z-pinch dynamic processes, a code of two-dimensional particle-in-cell (PIC) simulation has been developed in cylindrical coordinates. In principle, the Z-pinch of current-carrying rarefied deuterium plasma shell has been simulated by means of this code. Many results related to the microscopic processes of the Z-pinch are obtained. They include the spatio-temporal distributions of electromagnetic field, current density, forces experienced by the ions and electrons, positions and energy distributions of particles, and trailing mass and current. In radial direction, the electric and magnetic forces exerted on the electrons are comparable in magnitude, while the forces exerted on the ions are mainly the electric forces. So in the Z-pinch process, the electrons are first accelerated in Z direction and get higher velocities; then, they are driven inwards to the axis at the same time by the radial magnetic forces (i.e., Lorentz forces) of them. That causes the separations between the electrons and ions because the ion mass is much larger than the electron's, and in turn a strong electrostatic field is produced. The produced electrostatic field attracts the ions to move towards the electrons. When the electrons are driven along the radial direction to arrive at the axis, they shortly move inversely due to the static repellency among them and their tiny mass, while the ions continue to move inertially inwards, and later get into stagnation, and finally scatter outwards. Near the stagnation, the energies of the deuterium ions mostly range from 0.3 to 6 keV, while the electron energies are mostly from 5 to 35 keV. The radial components, which can contribute to the pinched plasma temperature, of the most probable energies of electron and ion at the stagnation are comparable to the Bennett equilibrium temperature (about 1 keV), and also to the highest temperatures of electron and ion obtained in one dimensional radiation

  8. Simulated annealing versus quantum annealing

    NASA Astrophysics Data System (ADS)

    Troyer, Matthias

    Based on simulated classical annealing and simulated quantum annealing using quantum Monte Carlo (QMC) simulations I will explore the question where physical or simulated quantum annealers may outperform classical optimization algorithms. Although the stochastic dynamics of QMC simulations is not the same as the unitary dynamics of a quantum system, I will first show that for the problem of quantum tunneling between two local minima both QMC simulations and a physical system exhibit the same scaling of tunneling times with barrier height. The scaling in both cases is O (Δ2) , where Δ is the tunneling splitting. An important consequence is that QMC simulations can be used to predict the performance of a quantum annealer for tunneling through a barrier. Furthermore, by using open instead of periodic boundary conditions in imaginary time, equivalent to a projector QMC algorithm, one obtains a quadratic speedup for QMC, and achieve linear scaling in Δ. I will then address the apparent contradiction between experiments on a D-Wave 2 system that failed to see evidence of quantum speedup and previous QMC results that indicated an advantage of quantum annealing over classical annealing for spin glasses. We find that this contradiction is resolved by taking the continuous time limit in the QMC simulations which then agree with the experimentally observed behavior and show no speedup for 2D spin glasses. However, QMC simulations with large time steps gain further advantage: they ``cheat'' by ignoring what happens during a (large) time step, and can thus outperform both simulated quantum annealers and classical annealers. I will then address the question how to optimally run a simulated or physical quantum annealer. Investigating the behavior of the tails of the distribution of runtimes for very hard instances we find that adiabatically slow annealing is far from optimal. On the contrary, many repeated relatively fast annealing runs can be orders of magnitude faster for

  9. Recent progress in the imaging of soil processes at the microscopic scale, and a look ahead

    NASA Astrophysics Data System (ADS)

    Garnier, Patricia; Baveye, Philippe C.; Pot, Valérie; Monga, Olivier; Portell, Xavier

    2016-04-01

    Over the last few years, tremendous progress has been achieved in the visualization of soil structures at the microscopic scale. Computed tomography, based on synchrotron X-ray beams or table-top equipment, allows the visualization of pore geometry at micrometric resolution. Chemical and microbiological information obtainable in 2D cuts through soils can now be interpolated, with the support of CT-data, to produce 3-dimensional maps. In parallel with these analytical advances, significant progress has also been achieved in the computer simulation and visualization of a range of physical, chemical, and microbiological processes taking place in soil pores. In terms of water distribution and transport in soils, for example, the use of Lattice-Boltzmann models as well as models based on geometric primitives has been shown recently to reproduce very faithfully observations made with synchrotron X-ray tomography. Coupling of these models with fungal and bacterial growth models allows the description of a range of microbiologically-mediated processes of great importance at the moment, for example in terms of carbon sequestration. In this talk, we shall review progress achieved to date in this field, indicate where questions remain unanswered, and point out areas where further advances are expected in the next few years.

  10. Approaches for ultrafast imaging of transient materials processes in the transmission electron microscope.

    PubMed

    LaGrange, Thomas; Reed, Bryan W; Santala, Melissa K; McKeown, Joseph T; Kulovits, Andreas; Wiezorek, Jörg M K; Nikolova, Liliya; Rosei, Federico; Siwick, Bradely J; Campbell, Geoffrey H

    2012-11-01

    The growing field of ultrafast materials science, aimed at exploring short-lived transient processes in materials on the microsecond to femtosecond timescales, has spawned the development of time-resolved, in situ techniques in electron microscopy capable of capturing these events. This article gives a brief overview of two principal approaches that have emerged in the past decade: the stroboscopic ultrafast electron microscope and the nanosecond-time-resolved single-shot instrument. The high time resolution is garnered through the use of advanced pulsed laser systems and a pump-probe experimental platforms using laser-driven photoemission processes to generate time-correlated electron probe pulses synchronized with laser-driven events in the specimen. Each technique has its advantages and limitations and thus is complementary in terms of the materials systems and processes that they can investigate. The stroboscopic approach can achieve atomic resolution and sub-picosecond time resolution for capturing transient events, though it is limited to highly repeatable (>10(6) cycles) materials processes, e.g., optically driven electronic phase transitions that must reset to the material's ground state within the repetition rate of the femtosecond laser. The single-shot approach can explore irreversible events in materials, but the spatial resolution is limited by electron source brightness and electron-electron interactions at nanosecond temporal resolutions and higher. The first part of the article will explain basic operating principles of the stroboscopic approach and briefly review recent applications of this technique. As the authors have pursued the development of the single-shot approach, the latter part of the review discusses its instrumentation design in detail and presents examples of materials science studies and the near-term instrumentation developments of this technique. PMID:22595460

  11. Environmental fatigue of an Al-Li-Cu alloy; Part II: Microscopic hydrogen cracking processes

    SciTech Connect

    Piascik, R.S.; Gangloff, R.P.

    1993-12-01

    Microscopic fatigue crack propagation (FCP) paths in peak-aged unrecrystallized alloy 2090 are identified as functions of intrinsic da/dN-{Delta}K kinetics and environment. The FCP rates in longitudinal-transverse (LT)-oriented 2090 are accelerated by hydrogen-producing environments (pure water vapor, moist air, and aqueous NaCl), as defined in Part 1. Subgrain boundary cracking (SGC) dominates for {Delta}K values where the cyclic plastic zone is sufficient to envelop subgrains. At low {Delta}K, when this crack tip process zone is smaller than the subgrain size, environmental FCP progresses on or near [100] or [110] planes, based on etch-pit shape. For inert environments (vacuum and He) and pure O{sub 2} with crack surface oxidation, FCP produces large facets along [111] oriented slip bands. This mode does not change with {Delta}K, and T{sub 1} decorated subgrain boundaries do not effect an expected da/dN-{Delta}K transition for the inert environments. Rather, the complex dependence of da/dN on {Delta}K is controlled by the environmental contribution to process zone microstructure-plastic strain interactions. A hydrogen embrittlement mechanism for FCP in 2090 is supported by similar brittle crack paths for low pressure water vapor and the electrolyte, the SGC and [100]/[110] crystallographic cracking modes, the influence of cyclic plastic zone volume ({Delta}K), and the benignancy of O{sub 2}. The SGC may be due to hydrogen production and trapping at T{sub 1} bearing sub-boundaries after process zone dislocation transport, while crystallographic cracking may be due to lattice decohesion or hydride cracking.

  12. Environmental fatigue of an Al-Li-Cu alloy. Part 2: Microscopic hydrogen cracking processes

    NASA Technical Reports Server (NTRS)

    Piascik, Robert S.; Gangloff, Richard P.

    1992-01-01

    Based on a fractographic analysis of fatigue crack propagation (FCP) in Al-Li-Cu alloy 2090 stressed in a variety of inert and embrittling environments, microscopic crack paths are identified and correlated with intrinsic da/dN-delta K kinetics. FCP rates in 2090 are accelerated by hydrogen producing environments (pure water vapor, moist air, and aqueous NaCl), as defined in Part 1. For these cases, subgrain boundary fatigue cracking (SGC) dominates for delta K values where the crack tip process zone, a significant fraction of the cyclic plastic zone, is sufficiently large to envelop 5 micron subgrains in the unrecrystallized microstructure. SGC may be due to strong hydrogen trapping at T1 precipitates concentrated at sub-boundaries. At low delta K, the plastic zone diameter is smaller than the subgrain size and FCP progresses along (100) planes due to either local lattice decohesion or aluminum-lithium hydride cracking. For inert environments (vacuum, helium, and oxygen), or at high delta K where the hydrogen effect on da/dN is small, FCP is along (111) slip planes; this mode does not transition with increasing delta K and plastic zone size. The SGC and (100) crystallographic cracking modes, and the governing influence of the crack tip process zone volume (delta K), support hydrogen embrittlement rather than a surface film rupture and anodic dissolution mechanism for environmental FCP. Multi-sloped log da/dN-log delta K behavior is produced by changes in process zone hydrogen-microstructure interactions, and not by purely micromechanical-microstructure interactions, in contradiction to microstructural distance-based fatigue models.

  13. Microscopic Model Calculations for the Magnetization Process of Layered Triangular-Lattice Quantum Antiferromagnets

    NASA Astrophysics Data System (ADS)

    Yamamoto, Daisuke; Marmorini, Giacomo; Danshita, Ippei

    2015-01-01

    Magnetization processes of spin-1 /2 layered triangular-lattice antiferromagnets (TLAFs) under a magnetic field H are studied by means of a numerical cluster mean-field method with a scaling scheme. We find that small antiferromagnetic couplings between the layers give rise to several types of extra quantum phase transitions among different high-field coplanar phases. Especially, a field-induced first-order transition is found to occur at H ≈0.7 Hs, where Hs is the saturation field, as another common quantum effect of ideal TLAFs in addition to the well-established one-third plateau. Our microscopic model calculation with appropriate parameters shows excellent agreement with experiments on Ba3CoSb2O9 [T. Susuki et al., Phys. Rev. Lett. 110, 267201 (2013)]. Given this fact, we suggest that the Co2 + -based compounds may allow for quantum simulations of intriguing properties of this simple frustrated model, such as quantum criticality and supersolid states.

  14. Microscopic model calculations for the magnetization process of layered triangular-lattice quantum antiferromagnets.

    PubMed

    Yamamoto, Daisuke; Marmorini, Giacomo; Danshita, Ippei

    2015-01-16

    Magnetization processes of spin-1/2 layered triangular-lattice antiferromagnets (TLAFs) under a magnetic field H are studied by means of a numerical cluster mean-field method with a scaling scheme. We find that small antiferromagnetic couplings between the layers give rise to several types of extra quantum phase transitions among different high-field coplanar phases. Especially, a field-induced first-order transition is found to occur at H≈0.7H_{s}, where H_{s} is the saturation field, as another common quantum effect of ideal TLAFs in addition to the well-established one-third plateau. Our microscopic model calculation with appropriate parameters shows excellent agreement with experiments on Ba_{3}CoSb_{2}O_{9} [T. Susuki et al., Phys. Rev. Lett. 110, 267201 (2013)]. Given this fact, we suggest that the Co^{2+}-based compounds may allow for quantum simulations of intriguing properties of this simple frustrated model, such as quantum criticality and supersolid states. PMID:25635561

  15. Microscopic insight into the DNA condensation process of a zwitterion-functionalized polycation.

    PubMed

    Sun, Hui; Zhou, Li; Chen, Xiaolu; Han, Xia; Wang, Rui; Liu, Honglai

    2016-11-01

    Zwitterion-functionalized polycations are ideal gene carriers with long circulation, high cellular uptaking and low cell viability. However, the trade-off between the DNA condensation efficiency and the cell viability must be addressed. The purpose of this study is to provide a microscopic insight into the DNA condensation process and to explore the effect of a zwitterionic block of zwitterion-functionalized polycation, which is of great significance in designing novel gene delivery systems. Poly[2-(dimethylamino)ethyl methacrylate-b-(sulfobetaine methacrylate)] (PDMAEMA-b-PSBMA) copolymers were synthesized and used as the model systems. Different from the conventional concept that the PSBMA zwitterionic block act only as the "stealthy" groups, the subtle differences in physical and colloidal characteristics between the polycation/DNA polyplexes show that the PSBMA segment is capable of wrapping DNA attributed to the quaternary ammonium cations, without compromising the DNA condensation capability. On the other hand, the incorporation of PSBMA block reduces the surface charge of the polyplexes, which substantially result in the inefficient transfection and the reduced cytotoxicity. PMID:27404763

  16. Analyzing the Role of Biofilm in Weathering Processes in the Rhizosphere with Various Microscopic Techniques

    NASA Astrophysics Data System (ADS)

    Niedziela, S.; Greenberg, K. A.; Dohnalkova, A.; Arey, B.; Balogh-Brunstad, Z.

    2011-12-01

    Biofilm is thought to have a significant role in biological weathering of minerals in the rhizosphere (root systems). The goal of our study is to examine the characteristics of rhizospheric biofilms under a range of base cation limitations and determine the best microscopic techniques to analyze the biofilm-microbe-fungus-mineral interface. We hypothesized that tree-fungus-bacteria association increases biofilm formation under severe base cation limitations that enhance mineral weathering rate and improve potassium and calcium retention and transport to the trees. Our hypothesis was tested in samples from a growth column experiment. Red pine (Pinus resinosa) trees were grown in leach tubes in quartz sand amended with 1 wt% biotite and anorthite. Half of the trees were inoculated with Suillus tomentosus and a group of soil bacteria, and the other half were left without microbial inoculation. Columns without any biology added served as controls. Calcium and potassium were supplied in irrigation water in 0, 30, 60 and 100% of an amount for healthy tree growth and the concentration of all other nutrients stayed constant in all solutions. After four weeks, the columns were destructively sampled and the root systems were analyzed by various microscopic techniques such as helium ion microscopy (HeIM), scanning electron microscopy (SEM) coupled with focused ion beam (FIB) and energy dispersive x-ray spectroscopy (EDS), cryo-SEM, and high resolution transmission electron microscopy (TEM) also coupled with EDS. These techniques were employed to collect the most information about the biofilm-microbe-fungus-mineral interface. The HeIM uses a beam of helium ions to produce 3-D high resolution images with greater depth of field than SEM and produces detailed surface topography results. The SEM coupled with EDS gives detailed chemical distribution of elements on a surface topography. The SEM coupled with FIB produces a cross-section of the analyzed material and allows a view

  17. A new approach to study local corrosion processes on steel surfaces by combining different microscopic techniques

    NASA Astrophysics Data System (ADS)

    Heyer, A.; D'Souza, F.; Bruin, A.; Ferrari, G.; Mol, J. M. C.; de Wit, J. H. W.

    2012-09-01

    Corrosion studies of materials on the micro or even nano-scale level are cumbersome due to instrumental limitations and handling procedures. If biological processes are involved the spatial resolution is even more important and sample preparation is usually the limitation. Attachment of bacteria on stainless steel surface is a complex interfacial process including interactions of bacterial cells and bacterial extracellular polymeric substances with the surface. To overcome the limitations in sample preparations and resolution we present a new stainless steel sample holder to switch among epifluorescent microscope (EFM), AFM and SEM at exactly the same position. Exemplary bacterial accumulation was studied by staining the bacterial DNA with a fluorescent dye over time. It was possible to distinguish among bacteria and other surface characteristic such as deformations or grain structures. Also surface topographic features such as roughness at the grain boundaries and deposits were quantified. All three techniques complement one another in the way that AFM is a high-resolution technique that does not allow to distinguish directly bacterial cell structures, whereas EFM offers excellent bacterial identification based on staining at a low resolution that can complement AFM images. Application of SEM in the last step will reveal inclusions and grain structure and combined with EDX gives the composition of the substrate, inclusions and corrosion deposit. The combination of the three high-resolution techniques enables a more detailed understanding of surface phenomena. The method itself is quite elegant and easy to handle which is an important aspect in materials research, especially when a high sample throughput is needed.

  18. A Study of the Nature of Students' Models of Microscopic Processes in the Context of Modern Physics Experiments.

    ERIC Educational Resources Information Center

    Thacker, Beth Ann

    2003-01-01

    Interviews university students in modern physics about their understanding of three fundamental experiments. Explores their development of models of microscopic processes. Uses interactive demonstrations to probe student understanding of modern physics experiments in two high school physics classes. Analyzes the nature of students' models and the…

  19. Post-annealing-free, room temperature processed nanocrystalline indium tin oxide thin films for plastic electronics

    NASA Astrophysics Data System (ADS)

    Nyoung Jang, Jin; Jong Lee, You; Jang, YunSung; Yun, JangWon; Yi, Seungjun; Hong, MunPyo

    2016-06-01

    In this study, we confirm that bombardment by high energy negative oxygen ions (NOIs) is the key origin of electro-optical property degradations in indium tin oxide (ITO) thin films formed by conventional plasma sputtering processes. To minimize the bombardment effect of NOIs, which are generated on the surface of the ITO targets and accelerated by the cathode sheath potential on the magnetron sputter gun (MSG), we introduce a magnetic field shielded sputtering (MFSS) system composed of a permanent magnetic array between the MSG and the substrate holder to block the arrival of energetic NOIs. The MFSS processed ITO thin films reveal a novel nanocrystal imbedded polymorphous structure, and present not only superior electro-optical characteristics but also higher gas diffusion barrier properties. To the best of our knowledge, no gas diffusion barrier composed of a single inorganic thin film formed by conventional plasma sputtering processes achieves such a low moisture permeability.

  20. Excimer laser annealing: A gold process for CZ silicon junction formation

    NASA Technical Reports Server (NTRS)

    Wong, David C.; Bottenberg, William R.; Byron, Stanley; Alexander, Paul

    1987-01-01

    A cold process using an excimer laser for junction formation in silicon has been evaluated as a way to avoid problems associated with thermal diffusion. Conventional thermal diffusion can cause bulk precipitation of SiOx and SiC or fail to completely activate the dopant, leaving a degenerate layer at the surface. Experiments were conducted to determine the feasibility of fabricating high quality p-n junctions using a pulsed excimer laser for junction formation at remelt temperature with ion-implanted surfaces. Solar-cell efficiency exceeding 16 percent was obtained using Czochralski single-crystal silicon without benefit of back surface field or surface passivation. Characterization shows that the formation of uniform, shallow junctions (approximately 0.25 micron) by excimer laser scanning preserves the minority carrier lifetime that leads to high current collection. However, the process is sensitive to initial surface conditions and handling parameters that drive the cost up.

  1. Microscopic Processes Involved in the Transition from a Disk to a Ring Sequence

    NASA Astrophysics Data System (ADS)

    Coppi, B.

    2006-10-01

    In a differentially rotating plasma structure, in the prevailing gravity of a central object, it is realistic to consider ɛm=Dm/(HvA)<< 1, where Dm= ηc^2/4 π, η is the plasma resistivity, vA is the Alfvén velocity, and H is the height of the structure. Therefore, the frozen-in- law can be applied when dealing with global scale distances. However, the transition from a disk configuration to a ring sequence configuration in a structure imbedded in an external magnetic field with a ``seed'' vertical component involves the formation of a periodic sequence of new closed magnetic surfaces^1 similar to those characteristic of Field Reverse Configurations. Pairs of counter-streaming (around the axis of rotation) current ``filaments'' form these very large aspect ratio toroidal configurations. The transition occurs when the field produced by the internal currents is equal (and of opposite direction) to that in which the structure is immersed. Then, magnetic reconnection has to be considered. The region in which the poloidal field is null can be viewed as a coalescence of two X-points and two O-points which, after the transition has occurred, tend to separate. The scale distances involved are much smaller than the characteristic global scale distances, such as H, the characteristic values of the collisional mean free paths need to be considered, and relevant microscopic reconnection processes are analyzed. *Sponsored in part by the U.S. DOE. B. Coppi Phys. Plasmas 12, 057301, (2005) B. Coppi and F. Rousseau, Ap. J. 641 (1), 458 (2006). external magnetic field with a ``seed'' vertical component involves the

  2. Estimation of sampling errors in a high-resolution TV microscope image-processing system.

    PubMed

    Harms, H; Aus, H M

    1984-05-01

    The basic postulate of this paper is that the commonly accepted sampling density of 2-4 pixels/micron in a high-resolution TV microscope system is too low to digitize exactly and analyze the complex cellular detail found in stained cell images. Depending on the specific microscope system, the required sampling density is much higher, lying between 15 and 30 pixels/micron. This sampling density is derived from the aliasing error, the resolution loss, and computational limitations. The mathematical and optical methods and equipment used to obtain these results are described in detail. PMID:6375997

  3. TiO2-coated mesoporous carbon: conventional vs. microwave-annealing process.

    PubMed

    Coromelci-Pastravanu, Cristina; Ignat, Maria; Popovici, Evelini; Harabagiu, Valeria

    2014-08-15

    The study of coating mesoporous carbon materials with titanium oxide nanoparticles is now becoming a promising and challenging area of research. To optimize the use of carbon materials in various applications, it is necessary to attach functional groups or other nanostructures to their surface. The combination of the distinctive properties of mesoporous carbon materials and titanium oxide is expected to be applied in field emission displays, nanoelectronic devices, novel catalysts, and polymer or ceramic reinforcement. But, their synthesis is still largely based on conventional techniques, such as wet impregnation followed by chemical reduction of the metal nanoparticle precursors, which takes time and money. The thermal heating based techniques are time consuming and often lack control of particle size and morphology. Hence, since there is a growing interest in microwave technology, an alternative way of power input into chemical reactions through dielectric heating is the use of microwaves. This work is focused on the advantages of microwave-assisted synthesis of TiO2-coated mesoporous carbon over conventional thermal heating method. The reviewed studies showed that the microwave-assisted synthesis of such composites allows processes to be completed within a shorter reaction time allowing the nanoparticles formation with superior properties than that obtained by conventional method. PMID:24997254

  4. Fabrication of High Jc (Bi,Pb)2223 Thin Films by PLD and Post-annealing Process

    NASA Astrophysics Data System (ADS)

    Takahira, S.; Ichino, Y.; Yoshida, Y.

    (Bi,Pb)2Sr2Ca2Cu3Oy ((Bi,Pb)2333) has high critical temperature (Tc) compared to REBa2Cu3Oy. However, (Bi,Pb)2223 has a disadvantage that the critical current density (Jc) seriously degrades in magnetic fields. We succeeded to fabricate (Bi,Pb)2223 epitaxial thin films by pulsed laser deposition (PLD) method using Nd:YAG pulsed laser deposition and post-annealing process. In addition, we tried to improve Jc in the magnetic fields by introducing Y2O3 or Al2O3 as artificial pinning centers (APCs). As a result, we fabricated (Bi,Pb)2223 thin films that had high Jc in self field at 77 K of 0.4 MA/cm2. The main phase of the thin films introduced Y2O3 was Bi2212. On the other hand, the main phase of the thin films introduced Al2O3 was Bi2223, however, the formation of Ca2PbO4 resulted in the decline of Jc.

  5. Microstructure and Mechanical Properties of Co21Cr22Cu22Fe21Ni14 Processed by High Pressure Torsion and Annealing

    NASA Astrophysics Data System (ADS)

    Park, Nokeun; Li, Xiang; Tsuji, Nobuhiro

    2015-08-01

    The strengthening mechanisms of Co21Cr22Cu22Fe21Ni14 multiple-principal element alloy processed by high pressure torsion (HPT) and annealing were examined. Two face-centered cubic (FCC) phases were observed in the as-cast alloy; one was a Cu-rich phase and the other was a Cu-lean one. In the HPT process, the microhardness increased from 190 HV to 470 HV at a strain of 157 due to strain hardening and grain refinement hardening. X-ray diffraction showed that the lattice parameters of the two FCC phases became closer to each other at higher HPT strain, indicating the alloying of Cu into the Cu-lean matrix. The HPT processed specimens were annealed at 500°C, 550°C, 600°C, and 650°C. The microhardness increased to 540 HV after annealing at temperatures lower than 650°C, whereas it decreased when the specimen was annealed at 650°C. The mean grain size of the specimens annealed at temperatures lower than 650°C was much smaller than 100 nm, and Cu-rich clusters with sizes ranging from 2 nm to 32 nm were distributed homogeneously. The reasons for the formation of the Cu-rich nano-clusters were discussed from a perspective of the positive mixing enthalpy of Cu in the alloy and thermalenergy for Cu diffusion at a given temperature. The dissolution and partitioning of two FCC phases played a key role in strengthening the Co21Cr22Cu22Fe21Ni14 system.

  6. Scanning Capacitace Microscope/Atomic Force Microscope/Scanning Tunneling Microscope Study of Ion-Implanted Silicon Surfaces

    NASA Astrophysics Data System (ADS)

    Tomiye, Hideto; Kawami, Hiroshi; Izawa, Michiyoshi; Yoshimura, Masamichi; Yao, Takafumi

    1995-06-01

    We have investigated the local electrical properties of ion-implanted Si using a combined scanning capacitance microscope (SCaM)/atomic force microscope (AFM)/scanning tunneling microscope (STM) with special attention paid to the effect of annealing. The STM image shows that the as-implanted area is insulating, while the unimplanted area is conductive, in an unannealed sample. Both STM and SCaM images clearly indicate that the implanted area is conductive with n-type behavior after annealing. However, the unimplanted area did not show p-type behavior but slightly n-type behavior due to the diffusion of P impurities during annealing.

  7. Scanning Electron Microscope Calibration Using a Multi-Image Non-Linear Minimization Process

    NASA Astrophysics Data System (ADS)

    Cui, Le; Marchand, Éric

    2015-04-01

    A scanning electron microscope (SEM) calibrating approach based on non-linear minimization procedure is presented in this article. A part of this article has been published in IEEE International Conference on Robotics and Automation (ICRA), 2014. . Both the intrinsic parameters and the extrinsic parameters estimations are achieved simultaneously by minimizing the registration error. The proposed approach considers multi-images of a multi-scale calibration pattern view from different positions and orientations. Since the projection geometry of the scanning electron microscope is different from that of a classical optical sensor, the perspective projection model and the parallel projection model are considered and compared with distortion models. Experiments are realized by varying the position and the orientation of a multi-scale chessboard calibration pattern from 300× to 10,000×. The experimental results show the efficiency and the accuracy of this approach.

  8. Macroscopic observables experimentally linked to microscopic processes in the explosive fracture and fragmentation of metals

    SciTech Connect

    Hull, Lawrence M

    2010-12-16

    The response of a metal element to explosive loading depends on a broad spectrum of explosive and metal properties, macroscopic geometry plays a crucial role in defining the localized loading history and the resulting gradients of interest, while microscopic effects and defects are generally believed responsible for damage nucleation. Certain experiments reduce the complexity by producing conditions that are uniform in some sense, allowing dynamic measurement of variables that can be correlated with corresponding microscopic effects observed in recovery experiments. Spherical expansion of thin shells, that eventually fragment, and steady wave loading of flat plates are two such experiments. Proton radiography, x-radiography, laser velocimetry, imaging IR, and visible light photography all have produced dynamic measurements in 4340 steel, copper, uranium alloys, tantalum, and titanium. Correlation of the macroscopic measurements with microscopy on recovered samples has been done with a statistical approach.

  9. Computer control of a scanning electron microscope for digital image processing of thermal-wave images

    NASA Technical Reports Server (NTRS)

    Gilbert, Percy; Jones, Robert E.; Kramarchuk, Ihor; Williams, Wallace D.; Pouch, John J.

    1987-01-01

    Using a recently developed technology called thermal-wave microscopy, NASA Lewis Research Center has developed a computer controlled submicron thermal-wave microscope for the purpose of investigating III-V compound semiconductor devices and materials. This paper describes the system's design and configuration and discusses the hardware and software capabilities. Knowledge of the Concurrent 3200 series computers is needed for a complete understanding of the material presented. However, concepts and procedures are of general interest.

  10. The induction of a graphite-like phase on diamond films by a Fe-coating/post-annealing process to improve their electron field emission properties

    SciTech Connect

    Huang, Pin-Chang; Shih, Wen-Ching; Chen, Huang-Chin; Lin, I-Nan

    2011-04-15

    The electron field emission (EFE) process for diamond films was tremendously enhanced by Fe-coating and post-annealing processes. Microstructural analysis indicates that the mechanism for the improvement in the EFE process is the formation of nanographites with good crystallinity that surround the Fe (or Fe{sub 3}C) nanoclusters. Presumably the nanographites were formed via the reaction of Fe clusters with diamond films, viz. by the dissolution of carbons into Fe (or Fe{sub 3}C) clusters and the reprecipitation of carbon species to the surface of the clusters, a process similar to the growth of carbon nanotubes via Fe clusters as catalyst. Not only is a sufficiently high post-annealing temperature (900 deg. C) required but also a highly active reducing atmosphere (NH{sub 3}) is needed to give a proper microstructure for enhancing the EFE process. The best EFE properties are obtained by post-annealing the Fe-coated diamond films at 900 deg. C in an NH{sub 3} environment for 5 min. The EFE behavior of the films can be turned on at E{sub 0} = 1.9 V/{mu}m, attaining a large EFE current density of 315 {mu}A/cm{sup 2} at an applied field of 8.8 V/{mu}m (extrapolation using the Fowler-Nordheim model leads to J{sub e} = 40.7 mA/cm{sup 2} at a 20 V/{mu}m applied field).

  11. The dynamic process and microscopic mechanism of extraordinary terahertz transmission through perforated superconducting films.

    PubMed

    Wu, J B; Zhang, X; Jin, B B; Liu, H T; Chen, Y H; Li, Z Y; Zhang, C H; Kang, L; Xu, W W; Chen, J; Wang, H B; Tonouchi, M; Wu, P H

    2015-01-01

    Superconductor is a compelling plasmonic medium at terahertz frequencies owing to its intrinsic low Ohmic loss and good tuning property. However, the microscopic physics of the interaction between terahertz wave and superconducting plasmonic structures is still unknown. In this paper, we conducted experiments of the enhanced terahertz transmission through a series of superconducting NbN subwavelength hole arrays, and employed microscopic hybrid wave model in theoretical analysis of the role of hybrid waves in the enhanced transmission. The theoretical calculation provided a good match of experimental data. In particular, we obtained the following results. When the width of the holes is far below wavelength, the enhanced transmission is mainly caused by localized resonance around individual holes. On the contrary, when the holes are large, hybrid waves scattered by the array of holes dominate the extraordinary transmission. The surface plasmon polaritions are proved to be launched on the surface of superconducting film and the excitation efficiency increases when the temperature approaches critical temperature and the working frequency goes near energy gap frequency. This work will enrich our knowledge on the microscopic physics of extraordinary optical transmission at terahertz frequencies and contribute to developing terahertz plasmonic devices. PMID:26498994

  12. The dynamic process and microscopic mechanism of extraordinary terahertz transmission through perforated superconducting films

    PubMed Central

    Wu, J. B.; Zhang, X.; Jin, B. B.; Liu, H. T.; Chen, Y. H.; Li, Z. Y.; Zhang, C. H.; Kang, L.; Xu, W. W.; Chen, J.; Wang, H. B.; Tonouchi, M.; Wu, P. H.

    2015-01-01

    Superconductor is a compelling plasmonic medium at terahertz frequencies owing to its intrinsic low Ohmic loss and good tuning property. However, the microscopic physics of the interaction between terahertz wave and superconducting plasmonic structures is still unknown. In this paper, we conducted experiments of the enhanced terahertz transmission through a series of superconducting NbN subwavelength hole arrays, and employed microscopic hybrid wave model in theoretical analysis of the role of hybrid waves in the enhanced transmission. The theoretical calculation provided a good match of experimental data. In particular, we obtained the following results. When the width of the holes is far below wavelength, the enhanced transmission is mainly caused by localized resonance around individual holes. On the contrary, when the holes are large, hybrid waves scattered by the array of holes dominate the extraordinary transmission. The surface plasmon polaritions are proved to be launched on the surface of superconducting film and the excitation efficiency increases when the temperature approaches critical temperature and the working frequency goes near energy gap frequency. This work will enrich our knowledge on the microscopic physics of extraordinary optical transmission at terahertz frequencies and contribute to developing terahertz plasmonic devices. PMID:26498994

  13. Semi insulating CdTe:Cl after elimination of inclusions and precipitates by post grown annealing

    NASA Astrophysics Data System (ADS)

    Franc, J.; Belas, E.; Bugár, M.; Hlídek, P.; Grill, R.; Yang, G.; Cavallini, A.; Fraboni, B.; Castaldini, A.; Assali, S.

    2012-11-01

    We present in this contribution results of two-step annealing, when the CdTe:Cl doped samples are at first annealed under Cd overpressure to remove inclusions and the re-annealed under Te overpressure to restore the high resistivity state. Investigation of samples after Cd rich annealing by infrared microscope has proven, that all inclusions are removed. Also Te nano precipitates were strongly influenced by the annealing process. The resistivity of the samples after Te-rich annealing was restored to values ( ~ 108-109Ωcm). We observed, however, decrease of mobility-lifetime product of electrons from 10-3cm2/Vs to 10-4cm2/Vs. In order to understand the reason of this decrease we performed a study of point defects before and after annealing by thermoelectric effect spectroscopy. It shows a decrease of concentrations of most deep levels after two-step annealing. This behavior is completely different compared to past annealing studies, where concentration of deep levels strongly increased after annealing. The only level with an increased concentration in the current study is the midgap level (E ~ 0.8 eV). At the same time we observed increase of micro-twins in the samples investigated by transmission electron microscopy. The decrease of charge collection efficiency after two-step annealing may be therefore connected with re-arrangement of near midgap levels due to increase of concentrations of structure defects (micro twins, dislocations) that accumulate in their surroundings point defects with energy ~ 0.75 eV.

  14. Kinetics and microscopic processes of long term fracture in polyethylene piping materials

    NASA Astrophysics Data System (ADS)

    Brown, N.; Lu, X.

    1992-07-01

    The report contains 9 completed works as follows: The Dependence of Slow Crack Growth in a Polyethylene Copolymer on Testing Temperature and Morphology; A Test of Slow Crack Growth Failure of PE Under Constant Load; Effect of Annealing on Slow Crack Growth in an Ethylene-Hexene Copolymer; The Fundamental Material Parameters that Govern Slow Crack Growth in Linear Polyethylene; Slow Crack Growth in Blends of HDPE and UHMWPE; The Mechanism of Fatigue Failure in a Polyethylene Copolymer; PENT Quality Control Test for PE Gas Pipes and Resins; International Round Robin Study of a Fatigue Test Approach to the Ranking of Polyethylene Pipe Material; and Proposed ASTM Specification for ASTM F17.40 Test Methods Committee.

  15. Lateral Temperature-Gradient Method for High-Throughput Characterization of Material Processing by Millisecond Laser Annealing.

    PubMed

    Bell, Robert T; Jacobs, Alan G; Sorg, Victoria C; Jung, Byungki; Hill, Megan O; Treml, Benjamin E; Thompson, Michael O

    2016-09-12

    A high-throughput method for characterizing the temperature dependence of material properties following microsecond to millisecond thermal annealing, exploiting the temperature gradients created by a lateral gradient laser spike anneal (lgLSA), is presented. Laser scans generate spatial thermal gradients of up to 5 °C/μm with peak temperatures ranging from ambient to in excess of 1400 °C, limited only by laser power and materials thermal limits. Discrete spatial property measurements across the temperature gradient are then equivalent to independent measurements after varying temperature anneals. Accurate temperature calibrations, essential to quantitative analysis, are critical and methods for both peak temperature and spatial/temporal temperature profile characterization are presented. These include absolute temperature calibrations based on melting and thermal decomposition, and time-resolved profiles measured using platinum thermistors. A variety of spatially resolved measurement probes, ranging from point-like continuous profiling to large area sampling, are discussed. Examples from annealing of III-V semiconductors, CdSe quantum dots, low-κ dielectrics, and block copolymers are included to demonstrate the flexibility, high throughput, and precision of this technique. PMID:27385487

  16. Periodically pulsed wet annealing approach for low-temperature processable amorphous InGaZnO thin film transistors with high electrical performance and ultrathin thickness.

    PubMed

    Kim, Ye Kyun; Ahn, Cheol Hyoun; Yun, Myeong Gu; Cho, Sung Woon; Kang, Won Jun; Cho, Hyung Koun

    2016-01-01

    In this paper, a simple and controllable "wet pulse annealing" technique for the fabrication of flexible amorphous InGaZnO thin film transistors (a-IGZO TFTs) processed at low temperature (150 °C) by using scalable vacuum deposition is proposed. This method entailed the quick injection of water vapor for 0.1 s and purge treatment in dry ambient in one cycle; the supply content of water vapor was simply controlled by the number of pulse repetitions. The electrical transport characteristics revealed a remarkable performance of the a-IGZO TFTs prepared at the maximum process temperature of 150 °C (field-effect mobility of 13.3 cm(2) V(-1) s(-1); Ion/Ioff ratio ≈ 10(8); reduced I-V hysteresis), comparable to that of a-IGZO TFTs annealed at 350 °C in dry ambient. Upon analysis of the angle-resolved x-ray photoelectron spectroscopy, the good performance was attributed to the effective suppression of the formation of hydroxide and oxygen-related defects. Finally, by using the wet pulse annealing process, we fabricated, on a plastic substrate, an ultrathin flexible a-IGZO TFT with good electrical and bending performances. PMID:27198067

  17. Particle capture processes and evaporation on a microscopic scale in wet filters.

    PubMed

    Mullins, Benjamin J; Braddock, Roger D; Agranovski, Igor E

    2004-11-01

    This paper details results of an experimental study of the capture of solid and liquid aerosols on fibrous filters wetted with water. A microscopic cell containing a single fibre (made from a variety of materials) was observed via a microscope, with a high speed CCD camera used to dynamically image the interactions between liquid droplets, zeolite and PSL particles and fibres. Variable quantities of liquid irrigation were used, and the possibility for subsequent fibre regeneration after clogging or drying was also studied. It was found that drainage of the wetting liquid (water) from the fibres occurred, even at very low irrigation rates when the droplet consisted almost completely of captured particles. It was also found that the fibre was rapidly loaded with captured particles when the irrigation was not supplied. However, almost complete regeneration (removal of the collected cake) by the liquid droplets occurred shortly after recommencement of the water supply. The study also examined the capture of oily liquid aerosols on fibres wetted with water. A predominance of the barrel shaped droplet on the fibre was observed, with oil droplets displacing water droplets (if the oil and fibre combination created a barrel shaped droplet), creating various compound droplets of oil and water not previously reported in literature. This preferential droplet shape implies that whatever the initial substance wetting a filter, a substance with a greater preferential adherence to the fibre will displace the former one. PMID:15380432

  18. Hierarchical processes in β-sheet peptide self-assembly from the microscopic to the mesoscopic level

    NASA Astrophysics Data System (ADS)

    Li, Deng; Hai, Xu

    2016-01-01

    Under appropriate physicochemical conditions, short peptide fragments and their synthetic mimics have been shown to form elongated cross-β nanostructures through self-assembly. The self-assembly process and the resultant peptide nanostructures are not only related to neurodegenerative diseases but also provide inspiration for the development of novel bionanomaterials. Both experimental and theoretical studies on peptide self-assembly have shown that the self-assembly process spans multiple time and length scales and is hierarchical. β-sheet self-assembly consists of three sub-processes from the microscopic to the mesoscopic level: β-sheet locking, lateral stacking, and morphological transformation. Detailed atomistic simulation studies have provided insight into the early stages of peptide nanostructure formation and the interplay between different non-covalent interactions at the microscopic level. This review gives a brief introduction of the hierarchical peptide self-assembly process and focuses on the roles of various non-covalent interactions in the sub-processes based on recent simulation, experimental, and theoretical studies. Project supported by the National Natural Science Foundation of China (Grant Nos. 21373270 and 11504431) and the Fundamental Research Funds for Central Universities of China (Grant No. 15CX02025A).

  19. Recycling process for recovery of gallium from GaN an e-waste of LED industry through ball milling, annealing and leaching.

    PubMed

    Swain, Basudev; Mishra, Chinmayee; Kang, Leeseung; Park, Kyung-Soo; Lee, Chan Gi; Hong, Hyun Seon

    2015-04-01

    Waste dust generated during manufacturing of LED contains significant amounts of gallium and indium, needs suitable treatment and can be an important resource for recovery. The LED industry waste dust contains primarily gallium as GaN. Leaching followed by purification technology is the green and clean technology. To develop treatment and recycling technology of these GaN bearing e-waste, leaching is the primary stage. In our current investigation possible process for treatment and quantitative leaching of gallium and indium from the GaN bearing e-waste or waste of LED industry dust has been developed. To recycle the waste and quantitative leaching of gallium, two different process flow sheets have been proposed. In one, process first the GaN of the waste the LED industry dust was leached at the optimum condition. Subsequently, the leach residue was mixed with Na2CO3, ball milled followed by annealing, again leached to recover gallium. In the second process, the waste LED industry dust was mixed with Na2CO3, after ball milling and annealing, followed acidic leaching. Without pretreatment, the gallium leaching was only 4.91 w/w % using 4M HCl, 100°C and pulp density of 20g/L. After mechano-chemical processing, both these processes achieved 73.68 w/w % of gallium leaching at their optimum condition. The developed process can treat and recycle any e-waste containing GaN through ball milling, annealing and leaching. PMID:25769129

  20. Germanium nanoislands grown by radio frequency magnetron sputtering: Annealing time dependent surface morphology and photoluminescence

    NASA Astrophysics Data System (ADS)

    Alireza, Samavati; Othaman, Z.; K. Ghoshal, S.; J. Amjad, R.

    2013-09-01

    Structural and optical properties of ~ 20 nm Ge nanoislands grown on Si(100) by radio frequency (rf) magnetron sputtering under varying annealing conditions are reported. Rapid thermal annealing at a temperature of 600°C for 30 s, 90 s, and 120 s are performed to examine the influence of annealing time on the surface morphology and photoluminescence properties. X-ray diffraction spectra reveal prominent Ge and GeO2 peaks highly sensitive to the annealing time. Atomic force microscope micrographs of the as-grown sample show pyramidal nanoislands with relatively high-density 1011 cm-2)). The nanoislands become dome-shaped upon annealing through a coarsening process mediated by Oswald ripening. The room temperature photoluminescence peaks for both as-grown 3.29 eV) and annealed 3.19 eV) samples consist of high intensity and broad emission, attributed to the effect of quantum confinement. The red shift (~0.10 eV) of the emission peak is attributed to the change in the size of the Ge nanoislands caused by annealing. Our easy fabrication method may contribute to the development of Ge nanostructure-based optoelectronics.

  1. Real-time scattered light dark-field microscopic imaging of the dynamic degradation process of sodium dimethyldithiocarbamate

    NASA Astrophysics Data System (ADS)

    Lei, Gang; Gao, Peng Fei; Liu, Hui; Huang, Cheng Zhi

    2015-12-01

    Single nanoparticle analysis (SNA) technique with the aid of a dark-field microscopic imaging (iDFM) technique has attracted wide attention owing to its high sensitivity. Considering that the degradation of pesticides can bring about serious problems in food and the environment, and that the real-time monitoring of the dynamic degradation process of pesticides can help understand and define their degradation mechanisms, herein we real-time monitored the decomposition dynamics of sodium dimethyldithiocarbamate (NaDDC) under neutral and alkaline conditions by imaging single silver nanoparticles (AgNPs) under a dark-field microscope (DFM); the localized surface plasmon resonance (LSPR) scattering signals were measured at a single nanoparticle level. As a result, the chemical mechanism of the degradation of NaDDC under neutral and alkaline conditions was proposed, and the inhibition effects of metal ions including Zn(ii) and Cu(ii) were investigated in order to understand the decomposition process in different environments. It was found that Cu(ii) forms the most stable complex with NaDDC with a stoichiometric ratio of 1 : 2, which greatly reduces the toxicity.Single nanoparticle analysis (SNA) technique with the aid of a dark-field microscopic imaging (iDFM) technique has attracted wide attention owing to its high sensitivity. Considering that the degradation of pesticides can bring about serious problems in food and the environment, and that the real-time monitoring of the dynamic degradation process of pesticides can help understand and define their degradation mechanisms, herein we real-time monitored the decomposition dynamics of sodium dimethyldithiocarbamate (NaDDC) under neutral and alkaline conditions by imaging single silver nanoparticles (AgNPs) under a dark-field microscope (DFM); the localized surface plasmon resonance (LSPR) scattering signals were measured at a single nanoparticle level. As a result, the chemical mechanism of the degradation of Na

  2. Scanning Electron Microscopic Investigations on Natural and Synthetic Gas Hydrates: New Insights into the Formation Process

    NASA Astrophysics Data System (ADS)

    Techmer, K. S.; Kuhs, W. F.; Heinrichs, T.; Bohrmann, G.

    2001-12-01

    We present results of field-emission scanning electron microscopic investigations of gas hydrates from shallow marine sediments of Cascadia margin as well as from synthesis experiments. The natural hydrates were taken by TV-grab sampling during the TECFLUX project on RV SONNE cruises, SO143 and SO148 on the southern summit of Hydrate Ridge. The samples are dominantly methane hydrates with a low content of H2S (1.5-3.0 vol%). The hydrates develop as pure white ice-like layers in otherwise soft sediment deposits. The synthetic gas hydrates were prepared from pure CH4 gas at variable pressure and temperature including experimental conditions similar to the natural situation. All synthetic hydrates show a porous microstructure with pore diameters of a few hundred nm (see figure) and grain sizes of a few †m[1]. Samples were transferred to a pre-cooled cryo-stage field-emission scanning electron microscope via an interlock. No decomposition was observed during our work, which was carried out below -165° C in a vacuum of <10-5 mbar by using an electron beam of 1.0-1.5 keV. The microscope is connected with an energy-dispersive X-ray spectrographic analyzer, which can clearly identify methane in the clathrate structure by detecting the carbon peak in the elemental spectrum. The microstructures of the natural gas hydrates vary greatly with the magnification. In general, large pores between a few to hundreds of †m in diameter are observed, and these have been also documented in thin sections. These pores are interpreted to originate from gas bubbles that ascend from deeper in the sediment. The pores develop in the pore water as skins of hydrate around the former gas bubbles. We investigated the inner part of the former bubble walls by FE-SEM and could document tiny filaments that often form a network of honeycomb-like structures. EDX- analyses show that these filaments have Cl-Peaks, and we think the filaments are remnants of pore water salt that cannot be incorporated

  3. Formative Processes of a Sliding Zone in Pelitic Schist - Implications of Microscopic Analyses on High-quality Drilled Cores

    NASA Astrophysics Data System (ADS)

    Yamasaki, S.; Chigira, M.

    2009-04-01

    Pelitic schist has been known to be easily deformed by gravitational force to form characteristic topographic and geologic features, but little is known about how they develop. This is mainly due to the fact that deformed politic schist is so fragile that it could not be obtained from subsurface without disturbance. We analyzed high-quality undisturbed cores obtained by using a sophisticated drilling technique from two typical pelitic schist landslide sites in Japan. We made analyses on physical, chemical, mineralogical properties and observations from mesoscopic to microscopic rock textures of these cores and found that a special layering of rock-forming minerals determines the locations of shearing by gravity and that there is specific water-rock interaction processes in pelitic schist. Pelitic schist consists of thinly alternating beds of black layers and quartz-rich layers, and a black layer has numerous microscopic layers containing abundant pyrite and graphite grains (pyrite-graphite layers). Many of the black layers were observed to have microfractures connected to open cracks, suggesting that relatively thick, continuous black layers are easily sheared to form an incipient sliding layer. Thus unevenly distributed pyrite-graphite layers likely to determine the potential location of microscopic slip in a rock mass. Shear displacement along black layers occurs unevenly, depending upon the microscopic heterogeneity in mineral composition as well as undulating shape of the layers. Open micro-cracks nearly perpendicular to the schistosity were commonly observed in quartz-rich layers in contact with black layers, suggesting that the shearing occurred with heterogeneous displacements along the black layer and that it occurred under the low confining pressure. This is in the incipient stage of a fracture zone. When shearing occurs along two thick neighboring black layers, the rock in between would be fractured, rotated and pulverized. In some cases, quartz

  4. Three-dimensional machining of carbon nanotube forests using water-assisted scanning electron microscope processing

    SciTech Connect

    Rajabifar, Bahram; Maschmann, Matthew R.; Kim, Sanha; Hart, A. John; Slinker, Keith; Ehlert, Gregory J.

    2015-10-05

    We demonstrate that vertically aligned carbon nanotubes (CNTs) can be precisely machined in a low pressure water vapor ambient using the electron beam of an environmental scanning electron microscope. The electron beam locally damages the irradiated regions of the CNT forest and also dissociates the water vapor molecules into reactive species including hydroxyl radicals. These species then locally oxidize the damaged region of the CNTs. The technique offers material removal capabilities ranging from selected CNTs to hundreds of cubic microns. We study how the material removal rate is influenced by the acceleration voltage, beam current, dwell time, operating pressure, and CNT orientation. Milled cuts with depths between 0–100 microns are generated, corresponding to a material removal rate of up to 20.1 μm{sup 3}/min. The technique produces little carbon residue and does not disturb the native morphology of the CNT network. Finally, we demonstrate direct machining of pyramidal surfaces and re-entrant cuts to create freestanding geometries.

  5. Three-dimensional machining of carbon nanotube forests using water-assisted scanning electron microscope processing

    NASA Astrophysics Data System (ADS)

    Rajabifar, Bahram; Kim, Sanha; Slinker, Keith; Ehlert, Gregory J.; Hart, A. John; Maschmann, Matthew R.

    2015-10-01

    We demonstrate that vertically aligned carbon nanotubes (CNTs) can be precisely machined in a low pressure water vapor ambient using the electron beam of an environmental scanning electron microscope. The electron beam locally damages the irradiated regions of the CNT forest and also dissociates the water vapor molecules into reactive species including hydroxyl radicals. These species then locally oxidize the damaged region of the CNTs. The technique offers material removal capabilities ranging from selected CNTs to hundreds of cubic microns. We study how the material removal rate is influenced by the acceleration voltage, beam current, dwell time, operating pressure, and CNT orientation. Milled cuts with depths between 0-100 microns are generated, corresponding to a material removal rate of up to 20.1 μm3/min. The technique produces little carbon residue and does not disturb the native morphology of the CNT network. Finally, we demonstrate direct machining of pyramidal surfaces and re-entrant cuts to create freestanding geometries.

  6. Thermal annealing study on P3HT: PCBM based bulk heterojunction organic solar cells using impedance spectroscopy

    SciTech Connect

    Gollu, Sankara Rao; Sharma, Ramakant G, Srinivas Gupta, Dipti

    2014-10-15

    Recently, Thermal annealing is an important process for bulk heterojunction organic solar cells (BHJ OSCs) to improve the device efficiency and performance of the organic solar cells. Here in, we have examined the changes in the efficiency and morphology of P3HT: PCBM film according to the thermal annealing temperature to find the changes during the annealing process by measuring the optical absorption, atomic force microscope and X-ray diffraction. We also investigated the effect of different annealing process conditions (without, pre- and post-annealing) on the device performance of the inverted bulk heterojunction organic solar cells consist the structure of ITO/ ZnO / P3HT: PCBM / MoO{sub 3}/ Al by measuring AC impedance characteristics. Particularly, the power conversion efficiency (PCE), crystalline nature of the polymer, light absorption and the surface smoothness of P3HT: PCBM films are significantly improved after the annealing process. These results indicated the improvement in terms of PCE, interface smoothness between the P3HT: PCBM and MoO{sub 3} layers of the post annealed device originated from the decrease of series resistance between P3HT: PCBM layer and Al electrodes, which could be due to decrease in the effective life time of charge carriers.

  7. True and false chirality, {ital CP} violation, and the breakdown of microscopic reversibility in chiral molecular and elementary particle processes

    SciTech Connect

    Barron, L.D.

    1996-07-01

    The concept of chirality is extended to cover systems that exhibit enantiomorphism on account of motion. This is achieved by applying time reversal in addition to space inversion and leads to a more precise definition of a chiral system. Although spatial enantiomorphism is sufficient to guarantee chirality in a stationary system such as a finite helix, enantiomorphous systems are not necessarily chiral when motion is involved, which leads to the concept of true and false chirality associated with time-invariant and time-noninvariant enantiomorphism, respectively. Only a truly chiral influence can induce an enantiomeric excess in a reaction that has reached true thermodynamic equilibrium (i.e., when all possible interconversion pathways have equilibrated); however, false chirality can suffice in a reaction under kinetic control due to a breakdown of microscopic reversibility analogous to that observed in particle-antiparticle processes involving the neutral K-meason as a result of {ital CP} violation, with the apparently contradictory kinetic and thermodynamic aspects being reconciled by an appeal to unitarity. This reveals that {ital CP} violation is analogous to chemical catalysis since it affects the rates of certain particle-antiparticle interconversion pathways without affecting the initial and final particle energies and hence the equilibrium thermodynamics. Consideration of falsely chiral influences, including the {open_quote}ratchet effect{close_quote} arising from the associated breakdown in microscopic reversibility, greatly enlarges the range of possible chiral advantage factors in prebiotic chemical processes if far from equilibrium. {copyright} {ital 1996 American Institute of Physics.}

  8. Uptake and processing of (/sup 3/H)retinoids in rat liver studied by electron microscopic autoradiography

    SciTech Connect

    Hendriks, H.F.; Elhanany, E.; Brouwer, A.; de Leeuw, A.M.; Knook, D.L.

    1988-03-01

    The role of rat liver cell organelles in retinoid uptake and processing was studied by electron microscopic autoradiography. (/sup 3/H)Retinoids were administered either orally, to make an inventory of the cell organelles involved, or intravenously as chylomicron remnant constituents to study retinoid processing by the liver with time. No qualitative differences were observed between the two routes of administration. Time-related changes in the distribution of grains were studied using chylomicron remnant (/sup 3/H)retinoids. The percentages of grains observed over cells and the space of Disse at 5 and 30 min after administration were, respectively: parenchymal cells, 72.6 and 70.4%; fat-storing cells, 5.0 and 18.1%, and the space of Disse, 14.4 and 8.9%. Low numbers of grains were observed over endothelial and Kupffer cells. The percentages of grains observed over parenchymal cell organelles were, respectively: sinusoidal area, 59.6 and 34.4%; smooth endoplasmic reticulum associated with glycogen, 13.8 and 13.4%; mitochondria, 5.4 and 13.6%; rough endoplasmic reticulum, 4.2 and 7.3%, and rough endoplasmic reticulum associated with mitochondria, 3.7 and 6.5%. It is concluded that chylomicron remnant (/sup 3/H)retinoids in combination with electron microscopic autoradiography provide a good system to study the liver processing of retinoids in vivo. These results, obtained in the intact liver under physiological conditions, further substantiate that retinoids are processed through parenchymal cells before storage occurs in fat-storing cell lipid droplets, that retinoid uptake is not mediated through lysosomes and that the endoplasmic reticulum is a major organelle in retinoid processing.

  9. Microscopic dynamics research on the "mature" process of dye-sensitized solar cells after injection of highly concentrated electrolyte.

    PubMed

    Liang, Zhongguan; Liu, Weiqing; Chen, Jun; Hu, Linhua; Dai, Songyuan

    2015-01-21

    After injection of electrolyte, the internal three-dimensional solid-liquid penetration system of dye-sensitized solar cells (DSCs) can take a period of time to reach "mature" state. This paper studies the changes of microscopic processes of DSCs including TiO2 energy-level movement, localized state distribution, charge accumulation, electron transport, and recombination dynamics, from the beginning of electrolyte injection to the time of reached mature state. The results show that the microscopic dynamics process of DSCs exhibited a time-dependent behavior and achieved maturity ∼12 h after injecting the electrolyte into DSCs. Within 0-12 h, several results were observed: (1) the conduction band edge of TiO2 moved slightly toward negative potential direction; (2) the localized states in the band gap of TiO2 was reduced according to the same distribution law; (3) the transport resistance in TiO2 film increased, and electron transport time was prolonged as the time of maturity went on, which indicated that the electron transport process is impeded gradually; (4) the recombination resistance at the TiO2/electrolyte (EL) interface increases, and electron lifetime gradually extends, therefore, the recombination process is continuously suppressed. Furthermore, results suggest that the parameters of EL/Pt-transparent conductive oxide (TCO) interface including the interfacial capacitance, electron-transfer resistance, and transfer time constant would change with time of maturity, indicating that the EL/Pt-TCO interface is a potential factor affecting the mature process of DSCs. PMID:25517177

  10. Real-time monitoring of the cell physiological and pathological processes using computer-aided phase microscope

    NASA Astrophysics Data System (ADS)

    Vasilenko, Irina A.; Shabalin, Vladimir; Tychinsky, Vladimir P.; Kufal, Georgy E.; Konradov, A.; Slinchenko, O. I.

    1996-01-01

    Living cells investigation and cell response to external factors are of great interest for practical medicine and biology. The main advantages of computer aided phase microscope (CPM) Cytoscan which permits us to observe the cell surface and internal structure consists in superresolution and the possibility of the dynamic processes registering. We attempt to characterize some aspects of the morphofunctional status of human lymphocytes determining the dynamics of the selected points in normal or pathological cells. To evaluate the lymphocyte homeostasis donors and persons of autoimmune diseases were analyzed and the changes of optical and geometrical cell parameters registered by CPM Cytoscan. The dynamic process registration allowed us to perform the real-time quantitative analysis of the living lymphocyte activity in norm and pathology.

  11. Recycling process for recovery of gallium from GaN an e-waste of LED industry through ball milling, annealing and leaching

    SciTech Connect

    Swain, Basudev Mishra, Chinmayee; Kang, Leeseung; Park, Kyung-Soo Lee, Chan Gi; Hong, Hyun Seon

    2015-04-15

    Waste dust generated during manufacturing of LED contains significant amounts of gallium and indium, needs suitable treatment and can be an important resource for recovery. The LED industry waste dust contains primarily gallium as GaN. Leaching followed by purification technology is the green and clean technology. To develop treatment and recycling technology of these GaN bearing e-waste, leaching is the primary stage. In our current investigation possible process for treatment and quantitative leaching of gallium and indium from the GaN bearing e-waste or waste of LED industry dust has been developed. To recycle the waste and quantitative leaching of gallium, two different process flow sheets have been proposed. In one, process first the GaN of the waste the LED industry dust was leached at the optimum condition. Subsequently, the leach residue was mixed with Na{sub 2}CO{sub 3}, ball milled followed by annealing, again leached to recover gallium. In the second process, the waste LED industry dust was mixed with Na{sub 2}CO{sub 3}, after ball milling and annealing, followed acidic leaching. Without pretreatment, the gallium leaching was only 4.91 w/w % using 4 M HCl, 100 °C and pulp density of 20 g/L. After mechano-chemical processing, both these processes achieved 73.68 w/w % of gallium leaching at their optimum condition. The developed process can treat and recycle any e-waste containing GaN through ball milling, annealing and leaching. - Highlights: • Simplest process for treatment of GaN an LED industry waste developed. • The process developed recovers gallium from waste LED waste dust. • Thermal analysis and phase properties of GaN to Ga{sub 2}O{sub 3} and GaN to NaGaO{sub 2} revealed. • Solid-state chemistry involved in this process reported. • Quantitative leaching of the GaN was achieved.

  12. Periodically pulsed wet annealing approach for low-temperature processable amorphous InGaZnO thin film transistors with high electrical performance and ultrathin thickness

    PubMed Central

    Kim, Ye Kyun; Ahn, Cheol Hyoun; Yun, Myeong Gu; Cho, Sung Woon; Kang, Won Jun; Cho, Hyung Koun

    2016-01-01

    In this paper, a simple and controllable “wet pulse annealing” technique for the fabrication of flexible amorphous InGaZnO thin film transistors (a-IGZO TFTs) processed at low temperature (150 °C) by using scalable vacuum deposition is proposed. This method entailed the quick injection of water vapor for 0.1 s and purge treatment in dry ambient in one cycle; the supply content of water vapor was simply controlled by the number of pulse repetitions. The electrical transport characteristics revealed a remarkable performance of the a-IGZO TFTs prepared at the maximum process temperature of 150 °C (field-effect mobility of 13.3 cm2 V−1 s−1; Ion/Ioff ratio ≈ 108; reduced I-V hysteresis), comparable to that of a-IGZO TFTs annealed at 350 °C in dry ambient. Upon analysis of the angle-resolved x-ray photoelectron spectroscopy, the good performance was attributed to the effective suppression of the formation of hydroxide and oxygen-related defects. Finally, by using the wet pulse annealing process, we fabricated, on a plastic substrate, an ultrathin flexible a-IGZO TFT with good electrical and bending performances. PMID:27198067

  13. Periodically pulsed wet annealing approach for low-temperature processable amorphous InGaZnO thin film transistors with high electrical performance and ultrathin thickness

    NASA Astrophysics Data System (ADS)

    Kim, Ye Kyun; Ahn, Cheol Hyoun; Yun, Myeong Gu; Cho, Sung Woon; Kang, Won Jun; Cho, Hyung Koun

    2016-05-01

    In this paper, a simple and controllable “wet pulse annealing” technique for the fabrication of flexible amorphous InGaZnO thin film transistors (a-IGZO TFTs) processed at low temperature (150 °C) by using scalable vacuum deposition is proposed. This method entailed the quick injection of water vapor for 0.1 s and purge treatment in dry ambient in one cycle; the supply content of water vapor was simply controlled by the number of pulse repetitions. The electrical transport characteristics revealed a remarkable performance of the a-IGZO TFTs prepared at the maximum process temperature of 150 °C (field-effect mobility of 13.3 cm2 V‑1 s‑1 Ion/Ioff ratio ≈ 108 reduced I-V hysteresis), comparable to that of a-IGZO TFTs annealed at 350 °C in dry ambient. Upon analysis of the angle-resolved x-ray photoelectron spectroscopy, the good performance was attributed to the effective suppression of the formation of hydroxide and oxygen-related defects. Finally, by using the wet pulse annealing process, we fabricated, on a plastic substrate, an ultrathin flexible a-IGZO TFT with good electrical and bending performances.

  14. Rotation and shape changes in {sup 151}Tb and {sup 196}Pb: Probes of nuclear structure and tunneling process in warm nuclei. II. Microscopic Monte Carlo simulation

    SciTech Connect

    Leoni, S.; Bracco, A.; Camera, F.; Corsi, A.; Crespi, F. C. L.; Montanari, D.; Pignanelli, M.; Benzoni, G.; Blasi, N.; Million, B.; Vigezzi, E.; Wieland, O.; Mason, P.; Matsuo, M.; Shimizu, Y. R.; Curien, D.; Duchene, G.; Robin, J.; Bednarczyk, P.; Kmiecik, M.

    2009-06-15

    A Monte Carlo simulation of the {gamma} decay of superdeformed nuclei has been developed. It is based on microscopic calculations for the energy levels, E2 decay probabilities, collective mass parameters, and potential energy barriers. The use of microscopically calculated quantities largely reduces the parameters of the simulation, allowing one to focus on the basic ingredients of the physical processes. Calculations are performed for the warm rotating superdeformed nuclei {sup 151}Tb and {sup 196}Pb, for which high statistics Euroball IV data are available. The dependence on the simulation parameters is investigated, together with the basic features of the microscopic calculations.

  15. Electron microscopic studies on the initial process of lysozyme crystal growth

    NASA Astrophysics Data System (ADS)

    Michinomae, M.; Mochizuki, M.; Ataka, M.

    1999-02-01

    The initial process of lysozyme crystallization has been investigated by negatively stained electron microscopy. In the initial process of crystallization, two steps were distinguished by the appearance of associating protein molecules. One is the formation of the short threads, and the other the formation of the spherical structure (looks like a rice-ball). From among the mass of the rice-balls, larger structure appears. Some of them show the arrangement of molecules as a crystalline lattice. The spacing between the molecules agrees with one of the lattice constants known for the tetragonal lysozyme crystals. The rice-balls may be taken into crystals as essential growth units. Similarly, the thread-like structures may be the unit to form the rice-balls that appear in the next step.

  16. Experimental study on microscopic evolving process of boiling overheat liquor in boiler under microcracking condition

    NASA Astrophysics Data System (ADS)

    Chen, Sining; He, Xuechao; Sun, Jinhua

    2009-07-01

    Boilers are frequently used in agricultural engineering. After micro cracks appear on the wall of the boiler for high pressure saturated liquor, the containing liquid will be overheated, rapidly boiled and expanded, which may result in explosion of the whole container. The evolving processes differ greatly by cracking conditions. In the experiment conducted in the this article, we made a small sized experimental device and applied high speed photography technology observing the simulated fierce boiling process of the high temperature and high pressure saturated water under overheat condition when micro cracking appears on boiler wall. According to our study, lower depressurization rate will suppress the boiling intensity of the overheated liquid and slow the growth of bubbles, decelerating the expansion of the two-phase flow compared with the boiling liquid expanding vapor explosion. The magnitude of overpressure in the container is also relatively smaller than overpressure in BLEVE.

  17. Microscopic processes in photo-encoded second-harmonic generation in glasses

    NASA Astrophysics Data System (ADS)

    Kyung, Jae Hyun

    1997-12-01

    For over a decade since the first discovery of self- organized second harmonic generation (SHG) in photo- encoded optical fibers by Ohmori and Sasaki, significant amount of research was devoted to understanding the mechanism leading to this unexpected phenomenon. Although vast amounts of experimental data and theoretical results have been gathered throughout the years, there is still no satisfactory theory to explain all the observed phenomena of SHG in glasses. A clear limitation in the experimental approach to this problem is that there have been no direct method in measuring the underlying charge distribution responsible for SHG in optically prepared glasses. In this dissertation, a novel technique using a newly discovered photo-induced selective etching effect is employed to probe the various charge distributions left behind by the optical encoding process, directly. This method eliminates the complications introduced by overlap integrals, wave diffraction, and controversies surrounding the interpretation of the measured free space modes in near- or far-field. Using the selective etching technique, two distinct transverse change distributions are revealed at different encoding intensities as well as a surprising transformation of the charge distributions between monochromatic and bichromatic excitations. Evidence of light-induced transition from bound to extended carrier transport is also observed in direct correlation to the threshold behavior of the SHG process. Finally, for the first time, the effective χ(2) grating in bulk glasses is directly mapped using this method. Armed with these observations, an outline for a more complete theory for the SHG process will be presented.

  18. Solution-processed n-type fullerene field-effect transistors prepared using CVD-grown graphene electrodes: improving performance with thermal annealing.

    PubMed

    Jeong, Yong Jin; Yun, Dong-Jin; Jang, Jaeyoung; Park, Seonuk; An, Tae Kyu; Kim, Lae Ho; Kim, Se Hyun; Park, Chan Eon

    2015-03-01

    Solution-processed organic field effect transistors (OFETs), which are amenable to facile large-area processing methods, have generated significant interest as key elements for use in all-organic electronic applications aimed at realizing low-cost, lightweight, and flexible devices. The low performance levels of n-type solution-processed bottom-contact OFETs unfortunately continue to pose a barrier to their commercialization. In this study, we introduced a combination of CVD-grown graphene source/drain (S/D) electrodes and fullerene (C60) in a solution-processable n-type semiconductor toward the fabrication of n-type bottom-contact OFETs. The C60 coating in the channel region was achieved by modifying the surface of the oxide gate dielectric layer with a phenyl group-terminated self-assembled monolayer (SAM). The graphene and phenyl group in the SAMs induced π-π interactions with C60, which facilitated the formation of a C60 coating. We also investigated the effects of thermal annealing on the reorganization properties and field-effect performances of the overlaying solution-processed C60 semiconductors. We found that thermal annealing of the C60 layer on the graphene surface improved the crystallinity of the face-centered cubic (fcc) phase structure, which improved the OFET performance and yielded mobilities of 0.055 cm(2) V(-1) s(-1). This approach enables the realization of solution-processed C60-based FETs using CVD-grown graphene S/D electrodes via inexpensive and solution-process techniques. PMID:25665649

  19. Basic properties of GaAs oxide generated by scanning probe microscope tip-induced nano-oxidation process

    NASA Astrophysics Data System (ADS)

    Okada, Yoshitaka; Iuchi, Yoshimasa; Kawabe, Mitsuo; Harris, James S.

    2000-07-01

    The basic properties of GaAs oxide generated by atomic force microscope (AFM) tip-induced nano-oxidation process have been investigated. The chemical analysis of the AFM tip-generated GaAs oxide was performed by using scanning microprobe x-ray photoelectron spectroscopy, and the main constituents of GaAs anodic oxide were determined to be Ga2O3 and As2O3. The electrical characterization showed that the electron transport across a GaAs oxide nanodot of ˜5.7 nm thickness, from a doped n+-Si tip into the n+-GaAs substrate follows the Fowler-Nordheim tunneling mechanism over a range of applied bias. Further, the tip-generated GaAs oxide nanodots were found to withstand moderate thermal treatments, but some volume reduction was observed.

  20. Magnetization process in a two-phase exchange-coupled system: A microscopic study

    SciTech Connect

    Ryan, D.H.; Feutrill, E.H.; Ding, J.

    1997-04-01

    The magnetization process in an exchange-coupled {alpha}-Fe+Nd{sub 2}Fe{sub 14}B nanocomposite has been studied by M{umlt o}ssbauer spectroscopy. Measurements in fields of up to 2 T confirm that the magnetization of the soft phase is strongly coupled to that of the hard phase. Analysis of magnetization curves and magic-angle spectra of saturated samples shows that the remanence is dominated by the hard phase. {copyright} {ital 1997 American Institute of Physics.}

  1. Performance improvement of GaN-based metal-semiconductor-metal photodiodes grown on Si(111) substrate by thermal cycle annealing process

    NASA Astrophysics Data System (ADS)

    Lin, Jyun-Hao; Huang, Shyh-Jer; Su, Yan-Kuin

    2014-01-01

    A simple thermal cycle annealing (TCA) process was used to improve the quality of GaN grown on a Si substrate. The X-ray diffraction (XRD) and etch pit density (EPD) results revealed that using more process cycles, the defect density cannot be further reduced. However, the performance of GaN-based metal-semiconductor-metal (MSM) photodiodes (PDs) prepared on Si substrates showed significant improvement. With a two-cycle TCA process, it is found that the dark current of the device was only 1.46 × 10-11 A, and the photo-to-dark-current contrast ratio was about 1.33 × 105 at 5 V. Also, the UV/visible rejection ratios can reach as high as 1077.

  2. Evaluation of freeze-substitution and conventional embedding protocols for routine electron microscopic processing of eubacteria

    SciTech Connect

    Graham, L.L.; Beveridge, T.J. )

    1990-04-01

    Freeze-substitution and more conventional embedding protocols were evaluated for their accurate preservation of eubacterial ultrastructure. Radioisotopes were specifically incorporated into the RNA, DNA, peptidoglycan, and lipopolysaccharide of two isogenic derivatives of Escherichia coli K-12 as representative gram-negative eubacteria and into the RNA and peptidoglycan of Bacillus subtilis strains 168 and W23 as representative gram-positive eubacteria. Radiolabeled bacteria were processed for electron microscopy by conventional methods with glutaraldehyde fixation, osmium tetroxide postfixation, dehydration in either a graded acetone or ethanol series, and infiltration in either Spurr or Epon 812 resin. A second set of cells were simultaneously freeze-substituted by plunge-freezing in liquid propane, substituting in anhydrous acetone containing 2% (wt/vol) osmium tetroxide, and 2% (wt/vol) uranyl acetate, and infiltrating in Epon 812. Extraction of radiolabeled cell components was monitored by liquid scintillation counting at all stages of processing to indicate retention of cell labels. Electron microscopy was also used to visually confirm ultrastructural integrity. Radiolabeled nucleic acid and wall components were extracted by both methods. In conventionally embedded specimens, dehydration was particularly damaging, with ethanol-dehydrated cells losing significantly more radiolabeled material during dehydration and subsequent infiltration than acetone-treated cells. For freeze-substituted specimens, postsubstitution washes in acetone were the most deleterious step for gram-negative cells, while infiltration was more damaging for gram-positive cells.

  3. Microscopic Origin of the Logarithmic Time Evolution of Aging Processes in Complex Systems

    NASA Astrophysics Data System (ADS)

    Lomholt, Michael A.; Lizana, Ludvig; Metzler, Ralf; Ambjörnsson, Tobias

    2013-05-01

    There exists compelling experimental evidence in numerous systems for logarithmically slow time evolution, yet its full theoretical understanding remains elusive. We here introduce and study a generic transition process in complex systems, based on nonrenewal, aging waiting times. Each state n of the system follows a local clock initiated at t=0. The random time τ between clock ticks follows the waiting time density ψ(τ). Transitions between states occur only at local clock ticks and are hence triggered by the local forward waiting time, rather than by ψ(τ). For power-law forms ψ(τ)≃τ-1-α (0<α<1) we obtain a logarithmic time evolution of the state number ⟨n(t)⟩≃log⁡(t/t0), while for α>2 the process becomes normal in the sense that ⟨n(t)⟩≃t. In the intermediate range 1<α<2 we find the power-law growth ⟨n(t)⟩≃tα-1. Our model provides a universal description for transition dynamics between aging and nonaging states.

  4. Microscopic origin of the logarithmic time evolution of aging processes in complex systems.

    PubMed

    Lomholt, Michael A; Lizana, Ludvig; Metzler, Ralf; Ambjörnsson, Tobias

    2013-05-17

    There exists compelling experimental evidence in numerous systems for logarithmically slow time evolution, yet its full theoretical understanding remains elusive. We here introduce and study a generic transition process in complex systems, based on nonrenewal, aging waiting times. Each state n of the system follows a local clock initiated at t = 0. The random time τ between clock ticks follows the waiting time density ψ(τ). Transitions between states occur only at local clock ticks and are hence triggered by the local forward waiting time, rather than by ψ(τ). For power-law forms ψ(τ) ≃ τ(-1-α) (0 < α < 1) we obtain a logarithmic time evolution of the state number ⟨n(t)⟩ ≃ log(t/t(0)), while for α > 2 the process becomes normal in the sense that ⟨n(t)⟩ ≃ t. In the intermediate range 1 < α < 2 we find the power-law growth ⟨n(t)⟩ ≃ t(α-1). Our model provides a universal description for transition dynamics between aging and nonaging states. PMID:25167457

  5. Microscopic colitis.

    PubMed

    Pardi, Darrell S

    2014-02-01

    Microscopic colitis is a frequent cause of chronic watery diarrhea, especially in older persons. Common associated symptoms include abdominal pain, arthralgias, and weight loss. The incidence of microscopic colitis had been increasing, although more recent studies have shown a stabilization of incidence rates. The diagnosis is based on characteristic histologic findings in a patient with diarrhea. Microscopic colitis can occur at any age, including in children, but it is primarily seen in the elderly. Several treatment options exist to treat the symptoms of microscopic colitis, although only budesonide has been well studied in randomized clinical trials. PMID:24267602

  6. Thermal-Wave Microscope

    NASA Technical Reports Server (NTRS)

    Jones, Robert E.; Kramarchuk, Ihor; Williams, Wallace D.; Pouch, John J.; Gilbert, Percy

    1989-01-01

    Computer-controlled thermal-wave microscope developed to investigate III-V compound semiconductor devices and materials. Is nondestructive technique providing information on subsurface thermal features of solid samples. Furthermore, because this is subsurface technique, three-dimensional imaging also possible. Microscope uses intensity-modulated electron beam of modified scanning electron microscope to generate thermal waves in sample. Acoustic waves generated by thermal waves received by transducer and processed in computer to form images displayed on video display of microscope or recorded on magnetic disk.

  7. Microscopic biomineralization processes and Zn bioavailability: a synchrotron-based investigation of Pistacia lentiscus L. roots.

    PubMed

    De Giudici, G; Medas, D; Meneghini, C; Casu, M A; Gianoncelli, A; Iadecola, A; Podda, S; Lattanzi, P

    2015-12-01

    Plants growing on polluted soils need to control the bioavailability of pollutants to reduce their toxicity. This study aims to reveal processes occurring at the soil-root interface of Pistacia lentiscus L. growing on the highly Zn-contaminated tailings of Campo Pisano mine (SW Sardinia, Italy), in order to shed light on possible mechanisms allowing for plant adaptation. The study combines conventional X-ray diffraction (XRD) and scanning electron microscopy (SEM) with advanced synchrotron-based techniques, micro-X-ray fluorescence mapping (μ-XRF) and X-ray absorption spectroscopy (XAS). Data analysis elucidates a mechanism used by P. lentiscus L. as response to high Zn concentration in soil. In particular, P. lentiscus roots take up Al, Si and Zn from the rhizosphere minerals in order to build biomineralizations that are part of survival strategy of the species, leading to formation of a Si-Al biomineralization coating the root epidermis. XAS analysis rules out Zn binding to organic molecules and indicates that Zn coordinates Si atoms stored in root epidermis leading to the precipitation of an amorphous Zn-silicate. These findings represent a step forward in understanding biological mechanisms and the resulting behaviour of minor and trace elements during plant-soil interaction and will have significant implications for development of phytoremediation techniques. PMID:26062465

  8. Magnetic lens apparatus for use in high-resolution scanning electron microscopes and lithographic processes

    DOEpatents

    Crewe, Albert V.

    2000-01-01

    Disclosed are lens apparatus in which a beam of charged particlesis brought to a focus by means of a magnetic field, the lens being situated behind the target position. In illustrative embodiments, a lens apparatus is employed in a scanning electron microscopeas the sole lens for high-resolution focusing of an electron beam, and in particular, an electron beam having an accelerating voltage of from about 10 to about 30,000 V. In one embodiment, the lens apparatus comprises an electrically-conducting coil arranged around the axis of the beam and a magnetic pole piece extending along the axis of the beam at least within the space surrounded by the coil. In other embodiments, the lens apparatus comprises a magnetic dipole or virtual magnetic monopole fabricated from a variety of materials, including permanent magnets, superconducting coils, and magnetizable spheres and needles contained within an energy-conducting coil. Multiple-array lens apparatus are also disclosed for simultaneous and/or consecutive imaging of multiple images on single or multiple specimens. The invention further provides apparatus, methods, and devices useful in focusing charged particle beams for lithographic processes.

  9. The reactivity of chlorite surfaces: Microscopic alteration processes and the transport behaviour of uranium(VI)

    NASA Astrophysics Data System (ADS)

    Bosbach, D.; Brandt, F.; Arnold, T.; Krawczyk-Baersch, E.; Bernhard, G.

    2003-04-01

    The transport of U(VI) in phyllite rocks or on granitic fractures is significantly affected by the dissolution of chlorite and the re-precipitation of various secondary phases. However, in order to be able to predict the behaviour of radionuclides in these systems a sound understanding of the reaction kinetics of chlorite alteration/dissolution processes as well as the precipitation of secondary phases is required. We have studied the dissolution of chlorite with mixed-flow reactor experiments and in-situ AFM observations far from equilibrium over a broad pH range. Key parameters such as the reactive surface area as well as the stoichiometry and pH dependency of the dissolution reaction were determined. Speciation calculations indicate that no secondary phases have formed (except under neutral pH conditions). Under acidic conditions the brucite-like layer of the chlorite structure dissolves faster than the 2:1 TOT layer whereas above pH 8 a reverse dissolution behaviour was observed. Under acidic conditions (pH < 5) chlorite transforms to a vermiculite-like clay mineral, which has also been identified in field studies. In addition, static batch dissolution experiments with chlorite were performed in order to mimic more closely natural systems. In these experiments various secondary phases including hydrous ferrous oxides (HFO) were formed as coatings on chlorite surfaces and as colloids in solution. Batch adsorption experiments indicate that U(VI) has a strong affinity to HFO and that retardation of U(VI) occurs via adsorption to immobile HFO coatings on chlorite surfaces. Heterogeneous HFO formation seems to be favoured on {hk0} edge surfaces in the near neutral pH range. The formation mechanism of HFO coatings was studied systematically with titration experiments, in order to be able to quantify the homogeneous and heterogeneous formation of these secondary phases as a function of the geochemical conditions.

  10. Effective thermionic work function measurements of zirconium carbide using a computer-processed image of a thermionic projection microscope pattern

    SciTech Connect

    Mackie, W.A.; Hinrichs, C.H.; Cohen, I.M.; Alin, J.S.; Schnitzler, D.T.; Carleson, P.; Ginn, R.; Krueger, P.; Vetter, C.G. ); Davis, P.R. )

    1990-05-01

    We report on a unique experimental method to determine thermionic work functions of major crystal planes of single crystal zirconium carbide. Applications for transition metal carbides could include cathodes for advanced thermionic energy conversion, radiation immune microcircuitry, {beta}-SiC substrates or high current density field emission cathodes. The primary emphasis of this paper is the analytical method used, that of computer processing a digitized image. ZrC single crystal specimens were prepared by floating zone arc refinement from sintered stock, yielding an average bulk stoichiometry of C/Zr=0.92. A 0.075 cm hemispherical cathode was prepared and mounted in a thermionic projection microscope (TPM) tube. The imaged patterns of thermally emitted electrons taken at various extraction voltages were digitized and computer analyzed to yield currents and corresponding emitting areas for major crystallographic planes. These data were taken at pyrometrically measured temperatures in the range 1700{lt}{ital T}{lt}2200 K. Schottky plots were then used to determine effective thermionic work functions as a function of crystallographic direction and temperature. Work function ordering for various crystal planes is reported through the TPM image processing method. Comparisons are made with effective thermionic and absolute (FERP) work function methods. To support the TPM image processing method, clean tungsten surfaces were examined and results are listed with accepted values.

  11. GenAnneal: Genetically modified Simulated Annealing

    NASA Astrophysics Data System (ADS)

    Tsoulos, Ioannis G.; Lagaris, Isaac E.

    2006-05-01

    A modification of the standard Simulated Annealing (SA) algorithm is presented for finding the global minimum of a continuous multidimensional, multimodal function. We report results of computational experiments with a set of test functions and we compare to methods of similar structure. The accompanying software accepts objective functions coded both in Fortran 77 and C++. Program summaryTitle of program:GenAnneal Catalogue identifier:ADXI_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADXI_v1_0 Program available from: CPC Program Library, Queen's University of Belfast, N. Ireland Computer for which the program is designed and others on which it has been tested: The tool is designed to be portable in all systems running the GNU C++ compiler Installation: University of Ioannina, Greece on Linux based machines Programming language used:GNU-C++, GNU-C, GNU Fortran 77 Memory required to execute with typical data: 200 KB No. of bits in a word: 32 No. of processors used: 1 Has the code been vectorized or parallelized?: No No. of bytes in distributed program, including test data, etc.:84 885 No. of lines in distributed program, including test data, etc.:14 896 Distribution format: tar.gz Nature of physical problem: A multitude of problems in science and engineering are often reduced to minimizing a function of many variables. There are instances that a local optimum does not correspond to the desired physical solution and hence the search for a better solution is required. Local optimization techniques are frequently trapped in local minima. Global optimization is hence the appropriate tool. For example, solving a non-linear system of equations via optimization, employing a "least squares" type of objective, one may encounter many local minima that do not correspond to solutions (i.e. they are far from zero). Typical running time: Depending on the objective function. Method of solution: We modified the process of step selection that the traditional Simulated

  12. Annealing behavior of high permeability amorphous alloys

    SciTech Connect

    Rabenberg, L.

    1980-06-01

    Effects of low temperature annealing on the magnetic properties of the amorphous alloy Co/sub 71/ /sub 4/Fe/sub 4/ /sub 6/Si/sub 9/ /sub 6/B/sub 14/ /sub 4/ were investigated. Annealing this alloy below 400/sup 0/C results in magnetic hardening; annealing above 400/sup 0/C but below the crystallization temperature results in magnetic softening. Above the crystallization temperature the alloy hardens drastically and irreversibly. Conventional and high resolution transmission electron microscopy were used to show that the magnetic property changes at low temperatures occur while the alloy is truly amorphous. By imaging the magnetic microstructures, Lorentz electron microscopy has been able to detect the presence of microscopic inhomogeneities in this alloy. The low temperature annealing behavior of this alloy has been explained in terms of atomic pair ordering in the presence of the internal molecular field. Lorentz electron microscopy has been used to confirm this explanation.

  13. Synthesis of CuO nanowires on Cu-foil using thermal oxidation method, a novel annealing process

    NASA Astrophysics Data System (ADS)

    Eshghi, Hosein; Goodarzi, Mehdi Torabi

    2016-02-01

    Cupric oxide (CuO) nanowires (NWs) on Cu-foils were prepared by thermal oxidation method in air atmosphere using two annealing manners (continuous and steps) in the temperature ranges of 400-500∘C and 400-600∘C. Morphology and microstructure of the NWs was studied using field effect scanning electron microscopy (FESEM), X-ray diffractogram (XRD), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). Optical reflectance spectrum was used for the optical investigation of the layers. We found the NWs formed have two different morphologies, curved and straight, with diameters between 50 nm and 200 nm and lengths between 5 μm and 10 μm. SAED pattern of a single NW revealed as a CuO single crystal with monoclinic structure. The reflectance spectra analysis based on Kubelka-Munk method showed that the band gap energy of the CuO NWs are varying in the range of 1.40-1.47 eV depending on the crystallite sizes of the NWs, a confirmation for the happening of the quantum confined effect in these samples.

  14. Computerized Measuring Microscope

    NASA Astrophysics Data System (ADS)

    Schoonmaker, Thomas D.

    1980-05-01

    In the manufacturing of printed circuit boards, microscopic analysis is an essential process control activity. An inspector microscopically analyzes board samples to deter-mine board lot quality and process conditions. Prior to computerizing, this sustained measurement-taking involved the tedious process of recording raw data, converting microscope filar readings, calculating averages, logging information in a job notebook, and completing detailed final lab reports. It is evident from this brief task description that this time-consuming repetitious data recording routine was an added burden to the already fatiguing visual inspection method and therefore was a prime candidate for automatic data capture and printout. Secondly, the creation of a permanent and easily accessible data base would improve process feedback and provide for a system with quick identification of any suspect boards if further assembly/testing exhibited board-related failures. This paper describes the evolution and implementation of a computer-aided microscopic inspection operation.

  15. Improvement of electrical characteristics of solution-processed InZnO thin-film transistor by vacuum annealing and nitrogen pressure treatment at 200 °C

    NASA Astrophysics Data System (ADS)

    Jeong, Woong Hee; Rim, You Seung; Lim Kim, Dong; Kim, Hyun Jae

    2015-12-01

    Electrical characteristics of the InZnO (IZO) thin-film transistor (TFT) using solution process were improved via vacuum annealing and N2 pressure treatment (PT) at 200 °C. Especially, the PT reduced the IZO film thickness and enhanced the IZO film density. It reduced the trap sites at the interface of IZO/gate insulator and those in the IZO bulk. Therefore, the PT IZO TFT exhibited a higher mobility of 4.44 cm2 V-1 s-1 and a steeper subthreshold swing of 0.79 V/decade than non-PT IZO TFT. The improvement of hysteresis on the PT IZO TFT was also observed.

  16. Microscopic Polyangiitis

    MedlinePlus

    ... include purplish bumps and spots pictured below (palpable purpura). These areas range in size from several millimeters ... Syndrome (EGPA) Cryoglobulinemia Giant Cell Arteritis Henoch-Schönlein Purpura Microscopic Polyangiitis Polyarteritis Nodosa Rheumatoid Vasculitis Takayasu’s Arteritis ...

  17. Rapid Annealing Of Amorphous Hydrogenated Carbon

    NASA Technical Reports Server (NTRS)

    Alterovitz, Samuel A.; Pouch, John J.; Warner, Joseph D.

    1989-01-01

    Report describes experiments to determine effects of rapid annealing on films of amorphous hydrogenated carbon. Study represents first efforts to provide information for applications of a-C:H films where rapid thermal processing required. Major finding, annealing causes abrupt increase in absorption and concomitant decrease in optical band gap. Most of change occurs during first 20 s, continues during longer annealing times. Extend of change increases with annealing temperature. Researchers hypothesize abrupt initial change caused by loss of hydrogen, while gradual subsequent change due to polymerization of remaining carbon into crystallites or sheets of graphite. Optical band gaps of unannealed specimens on silicon substrates lower than those of specimens on quartz substrates.

  18. Phase transformation from cubic ZnS to hexagonal ZnO by thermal annealing

    NASA Astrophysics Data System (ADS)

    Mahmood, K.; Asghar, M.; Amin, N.; Ali, Adnan

    2015-03-01

    We have investigated the mechanism of phase transformation from ZnS to hexagonal ZnO by high-temperature thermal annealing. The ZnS thin films were grown on Si (001) substrate by thermal evaporation system using ZnS powder as source material. The grown films were annealed at different temperatures and characterized by X-ray diffraction (XRD), photoluminescence (PL), four-point probe, scanning electron microscope (SEM) and energy dispersive X-ray diffraction (EDX). The results demonstrated that as-deposited ZnS film has mixed phases but high-temperature annealing leads to transition from ZnS to ZnO. The observed result can be explained as a two-step process: (1) high-energy O atoms replaced S atoms in lattice during annealing process, and (2) S atoms diffused into substrate and/or diffused out of the sample. The dissociation energy of ZnS calculated from the Arrhenius plot of 1000/T versus log (resistivity) was found to be 3.1 eV. PL spectra of as-grown sample exhibits a characteristic green emission at 2.4 eV of ZnS but annealed samples consist of band-to-band and defect emission of ZnO at 3.29 eV and 2.5 eV respectively. SEM and EDX measurements were additionally performed to strengthen the argument.

  19. Surface processes recorded by rocks and soils on Meridiani Planum, Mars: Microscopic Imager observations during Opportunity's first three extended missions

    NASA Astrophysics Data System (ADS)

    Herkenhoff, Ken E.; Grotzinger, John; Knoll, Andrew H.; McLennan, Scott M.; Weitz, Catherine; Yingst, Aileen; Anderson, Robert; Archinal, Brent A.; Arvidson, Raymond E.; Barrett, Janet M.; Becker, Kris J.; Bell, James F.; Budney, Charles; Chapman, Mary G.; Cook, Debbie; Ehlmann, Bethany; Franklin, Brenda; Gaddis, Lisa R.; Galuszka, Donna M.; Garcia, Patricia A.; Geissler, Paul; Hare, Trent M.; Howington-Kraus, Elpitha; Johnson, Jeffrey R.; Keszthelyi, Laszlo; Kirk, Randolph L.; Lanagan, Peter; Lee, Ella Mae; Leff, Craig; Maki, Justin N.; Mullins, Kevin F.; Parker, Timothy J.; Redding, Bonnie L.; Rosiek, Mark R.; Sims, Michael H.; Soderblom, Laurence A.; Spanovich, Nicole; Springer, Richard; Squyres, Steve W.; Stolper, Daniel; Sucharski, Robert M.; Sucharski, Tracie; Sullivan, Rob; Torson, James M.

    2008-11-01

    The Microscopic Imager (MI) on the Mars Exploration Rover Opportunity has returned images of Mars with higher resolution than any previous camera system, allowing detailed petrographic and sedimentological studies of the rocks and soils at the Meridiani Planum landing site. Designed to simulate a geologist's hand lens, the MI is mounted on Opportunity's instrument arm and can resolve objects 0.1 mm across or larger. This paper provides an overview of MI operations, data calibration, and analysis of MI data returned during the first 900 sols (Mars days) of the Opportunity landed mission. Analyses of Opportunity MI data have helped to resolve major questions about the origin of observed textures and features. These studies support eolian sediment transport, rather than impact surge processes, as the dominant depositional mechanism for Burns formation strata. MI stereo observations of a rock outcrop near the rim of Erebus Crater support the previous interpretation of similar sedimentary structures in Eagle Crater as being formed by surficial flow of liquid water. Well-sorted spherules dominate ripple surfaces on the Meridiani plains, and the size of spherules between ripples decreases by about 1 mm from north to south along Opportunity's traverse between Endurance and Erebus craters.

  20. Analysis of signal processing in vestibular circuits with a novel light-emitting diodes-based fluorescence microscope.

    PubMed

    Direnberger, Stephan; Banchi, Roberto; Brosel, Sonja; Seebacher, Christian; Laimgruber, Stefan; Uhl, Rainer; Felmy, Felix; Straka, Hans; Kunz, Lars

    2015-05-01

    Optical visualization of neural network activity is limited by imaging system-dependent technical tradeoffs. To overcome these constraints, we have developed a powerful low-cost and flexible imaging system with high spectral variability and unique spatio-temporal precision for simultaneous optical recording and manipulation of neural activity of large cell groups. The system comprises eight high-power light-emitting diodes, a camera with a large metal-oxide-semiconductor sensor and a high numerical aperture water-dipping objective. It allows fast and precise control of excitation and simultaneous low noise imaging at high resolution. Adjustable apertures generated two independent areas of variable size and position for simultaneous optical activation and image capture. The experimental applicability of this system was explored in semi-isolated preparations of larval axolotl (Ambystoma mexicanum) with intact inner ear organs and central nervous circuits. Cyclic galvanic stimulation of semicircular canals together with glutamate- and γ-aminobutyric acid (GABA)-uncaging caused a corresponding modulation of Ca(2+) transients in central vestibular neurons. These experiments revealed specific cellular properties as well as synaptic interactions between excitatory and inhibitory inputs, responsible for spatio-temporal-specific sensory signal processing. Location-specific GABA-uncaging revealed a potent inhibitory shunt of vestibular nerve afferent input in the predominating population of tonic vestibular neurons, indicating a considerable impact of local and commissural inhibitory circuits on the processing of head/body motion-related signals. The discovery of these previously unknown properties of vestibular computations demonstrates the merits of our novel microscope system for experimental applications in the field of neurobiology. PMID:25847143

  1. Scanning-electron-microscope image processing for accurate analysis of line-edge and line-width roughness

    NASA Astrophysics Data System (ADS)

    Hiraiwa, Atsushi; Nishida, Akio

    2012-03-01

    The control of line-edge or line-width roughness (LER/LWR) is a challenge especially for future devices that are fabricated using extreme-ultraviolet lithography. Accurate analysis of the LER/LWR plays an essential role in this challenge and requires the noise involved in scanning-electron-microscope (SEM) images to be reduced by appropriate image processing prior to analyses. In order to achieve this, the authors simulated SEM images using the Monte-Carlo method and detected line edges in experimental and these theoretical images after noise filtering using new imageanalysis software. The validity of these simulation and software was confirmed by a good agreement between the experimental and theoretical results. In the case when the image pixels aligned perpendicular (crosswise) to line edges were averaged, the variance var(φ) that was additionally induced by the image noise decreased with the number NPIX,X of averaged pixels but turned to increase for relatively large NPIX,X's. Real LER/LWR, however, remained unaffected. On the other hand, averaging image pixels aligned parallel (longitudinal) to line edges not only reduced var(φ) but smoothed the real LER/LWR. As a result, the nominal variance of the real LWR, obtained using simple arithmetic, monotonically decreased with the number NPIX,L of averaged pixels. Artifactual oscillations were additionally observed in power spectral densities. var(φ) in this case decreased in an inverse proportion to the square root of NPIX,L according to the statistical mechanism clarified here. In this way, image processing has a marked effect on the LER/LWR analysis and needs to be much more cared and appropriately applied. All the aforementioned results not only constitute a solid basis of but improve previous empirical instructions for accurate analyses. The most important instruction is to avoid the longitudinal averaging and to crosswise average an optimized number of image pixels consulting the equation derived in this

  2. An Introduction to Simulated Annealing

    ERIC Educational Resources Information Center

    Albright, Brian

    2007-01-01

    An attempt to model the physical process of annealing lead to the development of a type of combinatorial optimization algorithm that takes on the problem of getting trapped in a local minimum. The author presents a Microsoft Excel spreadsheet that illustrates how this works.

  3. The effect of annealing process on the optical and microwave dielectric properties of transparent MgAl2O4 ceramics by spark plasma sintering

    NASA Astrophysics Data System (ADS)

    Fu, Ping; Xu, Yong; Shi, Haohao; Zhang, Baohua; Ruan, Xuefeng; Lu, Wenzhong

    2014-05-01

    Transparent MgAl2O4 ceramics were fabricated by using spark plasma sintering (SPS). The effects of annealing temperature on the optical and microwave dielectric properties were investigated by positron annihilation technique and X-ray photoelectron spectroscopy (XPS). The results showed that the optimal annealing temperature for the optical property improvement was 900 °C and the in-line transmittance was improved to 74.9% at the wavelength of 550 nm. The further elevation of annealing temperature damaged the optical performance due to the combination of oxygen vacancies. The Q × f values of transparent MgAl2O4 ceramics were an overall increase from 800 °C to 1200 °C, but decreased at 1300 °C. It can be concluded that the annealing temperature plays an important role in the Q × f value, while a certain annealing temperature is corresponding to the best microwave dielectric property.

  4. Microscopic Polyangiitis

    PubMed Central

    Chung, Sharon A.; Seo, Philip

    2010-01-01

    Synopsis In 1923, Friedrich Wohlwill described two patients with a “microscopic form of periarteritis nodosa”, which was distinct from classical polyarteritis nodosa. This disease, now known as microscopic polyangiitis (MPA), is a primary systemic vasculitis characterized by inflammation of the small-caliber blood vessels and the presence of circulating antineutrophil cytoplasmic antibodies (ANCA). Typically, microscopic polyangiitis presents with glomerulonephritis and pulmonary capillaritis, although involvement of the skin, nerves, and gastrointestinal tract is not uncommon. Treatment of MPA generally requires use of a cytotoxic agent (such as cyclophosphamide) in addition to high-dose glucocorticoids. Recent research has focused on identifying alternate treatment strategies that minimize or eliminate exposure to cytotoxic agents. This article will review the history, pathogenesis, clinical manifestations, and treatment of MPA. PMID:20688249

  5. Martian Microscope

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The microscopic imager (circular device in center) is in clear view above the surface at Meridiani Planum, Mars, in this approximate true-color image taken by the panoramic camera on the Mars Exploration Rover Opportunity. The image was taken on the 9th sol of the rover's journey. The microscopic imager is located on the rover's instrument deployment device, or arm. The arrow is pointing to the lens of the instrument. Note the dust cover, which flips out to the left of the lens, is open. This approximated color image was created using the camera's violet and infrared filters as blue and red.

  6. A Review of Automatic Methods Based on Image Processing Techniques for Tuberculosis Detection from Microscopic Sputum Smear Images.

    PubMed

    Panicker, Rani Oomman; Soman, Biju; Saini, Gagan; Rajan, Jeny

    2016-01-01

    Tuberculosis (TB) is an infectious disease caused by the bacteria Mycobacterium tuberculosis. It primarily affects the lungs, but it can also affect other parts of the body. TB remains one of the leading causes of death in developing countries, and its recent resurgences in both developed and developing countries warrant global attention. The number of deaths due to TB is very high (as per the WHO report, 1.5 million died in 2013), although most are preventable if diagnosed early and treated. There are many tools for TB detection, but the most widely used one is sputum smear microscopy. It is done manually and is often time consuming; a laboratory technician is expected to spend at least 15 min per slide, limiting the number of slides that can be screened. Many countries, including India, have a dearth of properly trained technicians, and they often fail to detect TB cases due to the stress of a heavy workload. Automatic methods are generally considered as a solution to this problem. Attempts have been made to develop automatic approaches to identify TB bacteria from microscopic sputum smear images. In this paper, we provide a review of automatic methods based on image processing techniques published between 1998 and 2014. The review shows that the accuracy of algorithms for the automatic detection of TB increased significantly over the years and gladly acknowledges that commercial products based on published works also started appearing in the market. This review could be useful to researchers and practitioners working in the field of TB automation, providing a comprehensive and accessible overview of methods of this field of research. PMID:26573654

  7. Effects of Annealing Temperature on Thermomechanical Properties of Cu-Al-Ni Shape Memory Alloys

    NASA Astrophysics Data System (ADS)

    Canbay, C. Aksu; Karagoz, Z.

    2013-07-01

    The effects of the annealing temperature on structural properties and the phase transformation of a Cu-14.1Al-3.9Ni (mass %) shape memory alloy (SMA) have been investigated. The annealing process was carried out at temperatures in the range of to . The structural changes of the as-quenched and annealed samples were studied by optical microscope and X-ray diffraction measurements. The evolution of the transformation temperatures was studied by differential scanning calorimetry with different heating and cooling rates. The activation energy and thermodynamic parameters of the samples were determined. It was found that the heat treatment has an effect on the characteristic transformation temperatures and on thermodynamic parameters such as enthalpy, entropy, and activation energy. The crystallite size of the as-quenched and annealed samples were determined. Vickers hardness measurements of the as-quenched and annealed samples were also carried out. It is evaluated that the transformation parameters of a CuAlNi SMA can be controlled by heat treatment.

  8. Microstructural evolution in a low carbon steel during cold rolling and subsequent annealing.

    PubMed

    Ghassemali, E; Kermanpur, A; Najafizadeh, A

    2010-09-01

    Cold rolling with subsequent annealing of lath martensite structure could lead to the formation of nanostructures in low carbon steels. In the present work, the microstructural evolution of a 0.13% C steel during this process was studied. The specimens were austenitized at 950 degrees C followed by quenching in ice-brine to get martensitic structure. The quenched samples were aged at 200 degrees C for 30 min. These specimens were cold rolled up to 90% reduction in thickness without any intermediate annealing and then annealed at the temperatures from 400 to 600 degrees C. Scanning and transmission electron microscopy and color metallography was used to investigate the microstructure. Microscopic investigations showed that a multiphase nanostructure composed of equiaxed ferrite grains with the mean grain size of about 188 nm and small blocks of tempered martensite can be achieved under annealing at 400 degrees C for 90 min. Formation of the nanostructure was discussed from the viewpoint of characteristics of the martensite starting structure. Fragmentation of martensite lathes in cold rolling stage play an important role on recrystallization at annealing stage to get the ultrafine structure. PMID:21133169

  9. Recrystallization Behavior of a Heavily Deformed Austenitic Stainless Steel During Iterative Type Annealing

    NASA Astrophysics Data System (ADS)

    Ravi Kumar, B.; Sharma, Sailaja

    2014-09-01

    The study describes evolution of the recrystallization microstructure in an austenitic stainless steel during iterative or repetitive type annealing process. The starting heavily cold deformed microstructure consisted of a dual phase structure i.e., strain-induced martensite (SIM) (43 pct in volume) and heavily deformed large grained retained austenite. Recrystallization behavior was compared with Johnson Mehl Avrami and Kolmogorov model. Early annealing iterations led to reversion of SIM to reversed austenite. The microstructure changes observed in the retained austenite and in the reverted austenite were mapped by electron backscatter diffraction technique and transmission electron microscope. The reversed austenite was characterized by a fine polygonal substructure consisting of low-angle grain boundaries. With an increasing number of annealing repetitions, these boundaries were gradually replaced by high-angle grain boundaries and recrystallized into ultrafine-grained microstructure. On the other hand, recrystallization of retained austenite grains was sluggish in nature. Progress of recrystallization in these grains was found to take place by a gradual evolution of subgrains and their subsequent transformation into fine grains. The observed recrystallization characteristics suggest continuous recrystallization type process. The analysis provided basic insight into the recrystallization mechanisms that enable the processing of ultrafine-grained fcc steels by iterative type annealing. Tensile properties of the processed material showed a good combination of strength and ductility.

  10. Recrystallization Behavior of a Heavily Deformed Austenitic Stainless Steel During Iterative Type Annealing

    NASA Astrophysics Data System (ADS)

    Ravi Kumar, B.; Sharma, Sailaja

    2014-12-01

    The study describes evolution of the recrystallization microstructure in an austenitic stainless steel during iterative or repetitive type annealing process. The starting heavily cold deformed microstructure consisted of a dual phase structure i.e., strain-induced martensite (SIM) (43 pct in volume) and heavily deformed large grained retained austenite. Recrystallization behavior was compared with Johnson Mehl Avrami and Kolmogorov model. Early annealing iterations led to reversion of SIM to reversed austenite. The microstructure changes observed in the retained austenite and in the reverted austenite were mapped by electron backscatter diffraction technique and transmission electron microscope. The reversed austenite was characterized by a fine polygonal substructure consisting of low-angle grain boundaries. With an increasing number of annealing repetitions, these boundaries were gradually replaced by high-angle grain boundaries and recrystallized into ultrafine-grained microstructure. On the other hand, recrystallization of retained austenite grains was sluggish in nature. Progress of recrystallization in these grains was found to take place by a gradual evolution of subgrains and their subsequent transformation into fine grains. The observed recrystallization characteristics suggest continuous recrystallization type process. The analysis provided basic insight into the recrystallization mechanisms that enable the processing of ultrafine-grained fcc steels by iterative type annealing. Tensile properties of the processed material showed a good combination of strength and ductility.

  11. Stereoscopic Video Microscope

    NASA Astrophysics Data System (ADS)

    Butterfield, James F.

    1980-11-01

    The new electronic technology of three-dimensional video combined with the established. science of microscopy has created. a new instrument. the Stereoscopic Video Microscope. The specimen is illuminated so the stereoscopic objective lens focuses the stereo-pair of images side-by-side on the video camera's pick-up, tube. The resulting electronic signal can be enhanced, digitized, colorized, quantified, its polarity reverse., and its gray scale expanJed non-linearally. The signal can be transmitted over distances and can be stored on video. tape for later playback. The electronic signal is converted to a stereo-pair of visual images on the video monitor's cathode-ray-tube. A stereo-hood is used to fuse the two images for three-dimensional viewing. The conventional optical microscope has definite limitations, many of which can be eliminated by converting the optical image to an electronic signal in the video microscope. The principal aHvantages of the Stereoscopic Video Microscope compared to the conventional optical microscope are: great ease of viewing; group viewing; ability to easily recohd; and, the capability of processing the electronic signal for video. enhancement. The applications cover nearly all fields of microscopy. These include: microelectronics assembly, inspection, and research; biological, metallurgical, and che.illical research; and other industrial and medical uses. The Stereo-scopic Video Microscope is particularly useful for instructional and recordkeeping purposes. The video microscope can be monoscopic or three dimensional.

  12. Modified laser-annealing process for improving the quality of electrical P-N junctions and devices

    DOEpatents

    Wood, Richard F.; Young, Rosa T.

    1984-01-01

    The invention is a process for producing improved electrical-junction devices. The invention is applicable, for example, to a process in which a light-sensitive electrical-junction device is produced by (1) providing a body of crystalline semiconductor material having a doped surface layer, (2) irradiating the layer with at least one laser pulse to effect melting of the layer, (3) permitting recrystallization of the melted layer, and (4) providing the resulting body with electrical contacts. In accordance with the invention, the fill-factor and open-circuit-voltage parameters of the device are increased by conducting the irradiation with the substrate as a whole at a selected elevated temperature, the temperature being selected to effect a reduction in the rate of the recrystallization but insufficient to effect substantial migration of impurities within the body. In the case of doped silicon substrates, the substrate may be heated to a temperature in the range of from about 200.degree. C. to 500.degree. C.

  13. AUTOMATED MALLEABLE ANNEALING OVENS SLOWLY HEAT AND COOL CASTINGS AS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    AUTOMATED MALLEABLE ANNEALING OVENS SLOWLY HEAT AND COOL CASTINGS AS THEY MOVE IN BINS ALONG TRACKS IN THE OVEN BOTTOM IN THE MALLEABLE ANNEALING BUILDING. THIS PROCESS TRANSFORMS BRITTLE WHITE IRON CASTINGS INTO SOFTER, STRONGER MALLEABLE IRON. - Stockham Pipe & Fittings Company, Malleable Annealing Building, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  14. Crystal growth and annealing method and apparatus

    DOEpatents

    Gianoulakis, Steven E.; Sparrow, Robert

    2001-01-01

    A method and apparatus for producing crystals that minimizes birefringence even at large crystal sizes, and is suitable for production of CaF.sub.2 crystals. The method of the present invention comprises annealing a crystal by maintaining a minimal temperature gradient in the crystal while slowly reducing the bulk temperature of the crystal. An apparatus according to the present invention includes a thermal control system added to a crystal growth and annealing apparatus, wherein the thermal control system allows a temperature gradient during crystal growth but minimizes the temperature gradient during crystal annealing. An embodiment of the present invention comprises a secondary heater incorporated into a conventional crystal growth and annealing apparatus. The secondary heater supplies heat to minimize the temperature gradients in the crystal during the annealing process. The secondary heater can mount near the bottom of the crucible to effectively maintain appropriate temperature gradients.

  15. Annealing of Solar Cells and Other Thin Film Devices

    NASA Technical Reports Server (NTRS)

    Escobar, Hector; Kuhlman, Franz; Dils, D. W.; Lush, G. B.; Mackey, Willie R. (Technical Monitor)

    2001-01-01

    Annealing is a key step in most semiconductor fabrication processes, especially for thin films where annealing enhances performance by healing defects and increasing grain sizes. We have employed a new annealing oven for the annealing of CdTe-based solar cells and have been using this system in an attempt to grow US on top of CdTe by annealing in the presence of H2S gas. Preliminary results of this process on CdTe solar cells and other thin-film devices will be presented.

  16. Effect of In Situ Thermal Annealing Process on Structural, Optical and Electrical Properties of CdSCdTe Thin-Film Solar Cells Fabricated by Pulsed Laser Deposition

    NASA Astrophysics Data System (ADS)

    Al-mebir, Alaa Ayad Khedhair

    Cadmium Telluride has long been recognized as the second lowest- cost material after Si in the world photovoltaic market, specifically for thin-film solar cells. The two attractive properties of the CdTe are its nearly ideal band gap of ˜1.5 eV for single p-n junction photovoltaic and its high optical absorption coefficient up to 105 cm-1. Therefore, a thickness of ˜1 mum of CdTe can absorb up to 90% of the incident light. The key to high-performance thin film CdTe-based solar cells is controlling microstructure of the CdS/CdTe through obtaining high-quality crystalline CdTe thin films that have low density pinholes and other defects and form high-quality p-n heterojunction interfaces on the CdS or other window layers. Considering these, the relative high temperatures used for CdTe thick film growth may not be suitable in the thin film case due to lack of control in CdTe microstructure evolution. Therefore, development of low-temperature processes for CdTe thin film solar cells is important to achieving a precise control of the CdS/CdTe microstructure and optoelectronic properties. In addition, low temperatures provide benefits in wider selection of substrates especially those for low-cost, flexible solar cells applications. However, the CdS/CdTe solar cells based on thin CdTe films fabricated at low temperature have generally poor performance as a result of increased density of grain boundaries and defects. In order to address this issue, we have developed an in situ thermal annealing process (iTAP) immediately after the CdS/CdTe deposition using Pulsed laser deposition (PLD) at 200 °C and before the common ex situ CdCl2 annealing typically employed for optimization of the CdTe-based solar cells. A systematic study on the microstructure, optical and optoelectronic properties of CdS/CdTe solar cells processed under different iTAP conditions has been carried out. It has been found that these physical properties depend sensitively on the iTAP processing conditions

  17. An in situ annealing study of lead implanted single crystal calcium titanate

    NASA Astrophysics Data System (ADS)

    Rankin, J.; Hobbs, L. W.; Boatner, L. A.; White, C. W.

    1988-05-01

    In situ annealing studies have been carried out in ion-implanted single crystals of CaTiO 3. These crystals were implanted along both the a and b axes of this orthorhombic perovskite structure (Pcmn). Through the use of a Panasonic video cassette recorder connected to a Gatan television system on a JEOL 200CX transmission electron microscope, the regrowth process was observed and the growth rate monitored. Samples were annealed in a Gatan single tilt hot stage at ˜ 475° C. The near-surface region of this material, approximately 190 nm, is turned amorphous by the implantation of 540 keV Pb ions at a fluence of 1 × 10 15/cm 2. Annealing at 475° C results in the epitaxial regrowth of the damaged region. The regrowth process begins at the original amorphous/crystalline interface and proceeds outward to the surface. This phenomenon has been studied for implantations along both the <010> and the <100> crystallographic directions. For constant accelerating voltage and fluence of the implanted lead ions, transmission electron microscopy (TEM) and Rutherford backscattering spectroscopy (RBS) [C.W. White et al., to be published in Proc. of Radiation Effects in Insulators, Lyon, France, 1987.] indicate that the regrowth rate is linear with time but strongly dependent on the oxygen partial pressure in the annealing atmosphere, and the implantation and subsequent regrowth direction.

  18. Near-infrared microscopic methods for the detection and quantification of processed by-products of animal origin

    NASA Astrophysics Data System (ADS)

    Abbas, O.; Fernández Pierna, J. A.; Dardenne, P.; Baeten, V.

    2010-04-01

    Since the BSE crisis, researches concern mainly the detection, identification, and quantification of meat and bone meal with an important focus on the development of new analytical methods. Microscopic based spectroscopy methods (NIR microscopy - NIRM or/and NIR hyperspectral imaging) have been proposed as complementary methods to the official method; the optical microscopy. NIR spectroscopy offers the advantage of being rapid, accurate and independent of human analyst skills. The combination of an NIR detector and a microscope or a camera allows the collection of high quality spectra for small feed particles having a size larger than 50 μm. Several studies undertaken have demonstrated the clear potential of NIR microscopic methods for the detection of animal particles in both raw and sediment fractions. Samples are sieved and only the gross fraction (superior than 250 μm) is investigated. Proposed methodologies have been developed to assure, with an acceptable level of confidence (95%), the detection of at least one animal particle when a feed sample is adulterated at a level of 0.1%. NIRM and NIR hyperspectral imaging are running under accreditation ISO 17025 since 2005 at CRA-W. A quantitative NIRM approach has been developed in order to fulfill the new requirements of the European commission policies. The capacities of NIRM method have been improved; only the raw fraction is analyzed, both the gross and the fine fractions of the samples are considered, and the acquisition parameters are optimized (the aperture, the gap, and the composition of the animal feed). A mapping method for a faster collection of spectra is also developed. The aim of this work is to show the new advances in the analytical methods developed in the frame of the feed ban applied in Europe.

  19. Effects of rolling temperature and subsequent annealing on mechanical properties of ultrafine-grained Cu–Zn–Si alloy

    SciTech Connect

    Zhang, Xiangkai; Yang, Xuyue; Chen, Wei; Qin, Jia; Fouse, Jiaping

    2015-08-15

    The effects of rolling temperature and subsequent annealing on mechanical properties of Cu–Zn–Si alloy were investigated by using X-ray diffraction, transmission electron microscope, electron back scattered diffraction and tensile tests. The Cu–Zn–Si alloy has been processed at cryogenic temperature (approximately 77 K) and room temperature up to different rolling strains. It has been identified that the cryorolled Cu–Zn–Si alloy samples show a higher strength compared with those room temperature rolled samples. The improved strength of cryorolled samples is resulted from grain size effect and higher densities of dislocations and deformation twins. And subsequent annealing, as a post-heat treatment, enhanced the ductility. An obvious increase in uniform elongation appears when the volume fraction of static recrystallization grains exceeds 25%. The strength–ductility combination of the annealed cryorolled samples is superior to that of annealed room temperature rolled samples, owing to the finer grains, high fractions of high angle grain boundaries and twins. - Highlights: • An increase in hardness of Cu–Zn–Si alloy is noticed during annealing process. • Thermal stability is reduced in Cu–Zn–Si alloy by cryorolling. • An obvious enhancement in UE is noticed when fraction of SRX grains exceeds 25%. • A superior strength–ductility combination is achieved in the cryorolling samples.

  20. Annealing induced interfacial layers in niobium-clad stainless steel developed as a bipolar plate material for polymer electrolyte membrane fuel cell stacks

    SciTech Connect

    Hong, Sung Tae; Weil, K. Scott; Choi, Jung-Pyung; Bae, In-Tae; Pan, Jwo

    2010-05-01

    Niobium (Nb)-clad 304L stainless steel (SS) manufactured by cold rolling is currently under consideration for use as a bipolar plate material in polymer electrolyte membrane fuel cell (PEMFC) stacks. To make the fabrication of bipolar plates using the Nb-clad SS feasible, annealing may be necessary for the Nb-clad SS to reduce the springback induced by cold rolling. However, the annealing can develop an interfacial layer between the Nb cladding and the SS core and the interfacial layer plays a key role in the failure of the Nb-clad SS as reported earlier [JPS our work]. In this investigation, the Nb-clad SS specimens in as-rolled condition were annealed at different combinations of temperature and time. Based on the results of scanning electron microscope (SEM) analysis, an annealing process map for the Nb-clad SS was obtained. The results of SEM analysis and Transmission Electron Microscope (TEM) analysis also suggest that different interfacial layers occurred based on the given annealing conditions.

  1. Effect of thermal annealing on the optical properties of CdGeAs2 wafers

    NASA Astrophysics Data System (ADS)

    Huang, Wei; Zhao, Beijun; Zhu, Shifu; He, Zhiyu; Chen, Baojun; Li, Jiawei; Yu, You; Tang, Jingjing; Liu, Weijia

    2013-01-01

    A crack-free CdGeAs2 single crystal 15 mm in diameter and 50 mm in length was grown in a three-zone tubular furnace by the modified vertical Bridgman method. During the annealing processes, the effects of treatments with different atmosphere, different temperatures and time were investigated. The as-grown and annealed wafers were characterized using X-ray diffractometer (XRD), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and IR microscope. Conclusively, the results confirm annealing could improve the optical qualities of as-grown CdGeAs2 crystal. The best result was obtained under cover-up with CdGeAs2 polycrystalline powder at 450 °C for 150 h and the IR transmittance of the wafer measured by FTIR was up to 48.65% nearby 5.5 μm and exceeded 50% in the range of 8-12 μm. Additionally, the monolithic homogeneity of the crystal has also been greatly improved after annealing under cover-up with polycrystalline powder.

  2. High-temperature annealing of proton irradiated beryllium - A dilatometry-based study

    NASA Astrophysics Data System (ADS)

    Simos, Nikolaos; Elbakhshwan, Mohamed; Zhong, Zhong; Ghose, Sanjit; Savkliyildiz, Ilyas

    2016-08-01

    Ssbnd 200 F grade beryllium has been irradiated with 160 MeV protons up to 1.2 1020 cm-2 peak fluence and irradiation temperatures in the range of 100-200 °C. To address the effect of proton irradiation on dimensional stability, an important parameter in its consideration in fusion reactor applications, and to simulate high temperature irradiation conditions, multi-stage annealing using high precision dilatometry to temperatures up to 740 °C were conducted in air. X-ray diffraction studies were also performed to compliment the macroscopic thermal study and offer a microscopic view of the irradiation effects on the crystal lattice. The primary objective was to qualify the competing dimensional change processes occurring at elevated temperatures namely manufacturing defect annealing, lattice parameter recovery, transmutation 4He and 3H diffusion and swelling and oxidation kinetics. Further, quantification of the effect of irradiation dose and annealing temperature and duration on dimensional changes is sought. The study revealed the presence of manufacturing porosity in the beryllium grade, the oxidation acceleration effect of irradiation including the discontinuous character of oxidation advancement, the effect of annealing duration on the recovery of lattice parameters recovery and the triggering temperature for transmutation gas diffusion leading to swelling.

  3. Effect of Annealing Time Process on the pH Sensitivity of Spin-coated TiO2/ ZnO Bilayer Film

    NASA Astrophysics Data System (ADS)

    Rahman, R. A.; Zulkefle, M. A.; Yusof, K. A.; Abdullah, W. F. H.; Rusop, M.; Herman, S. H.

    2015-11-01

    This paper presents an investigation on titanium dioxide (TiO2) and zinc oxide (ZnO) bilayer film, which is used as sensing membrane for extended-gate field effect transistor (EGFET) for pH sensing application. TiO2/ZnO thin films were deposited using sol-gel spin coating method on indium tin oxide (ITO) substrates. After the deposition, the bilayer films were annealed at constant temperatures which is 400 °C for 15, 30, 40 and 60 minutes. The sensitivity of the TiO2 thin film towards pH buffer solution was measured by dipping the sensing membrane in pH4, pH7 and pH10 buffer solution. By varying the annealing time, we found that the TiO2/ZnO thin film annealed at 400°C for 15 minutes gave the highest sensitivity compared to other annealing conditions, with the value of 64.87 mV/pH.

  4. Growth Kinetics of Microscopic Silicon Rods Grown on Silicon Substrates by the Pyrolytic Laser-Induced Chemical Vapor Deposition Process

    NASA Astrophysics Data System (ADS)

    Park, Se Il; Lee, Sang Soo

    1990-01-01

    By using a cw Ar+ ion laser beam, microscopic crystalline silicon rods ≈ 102 μm in diameter and ≈ 103 μm in height have been grown on a silicon substrate by pyrolytic dissociation of SiH4. The kinetics of lateral growth of the silicon rods is derived from the time integration of the Arrhenius equation using a reasonable assumption that the temperature on the edge of the deposit saturates inversely to the substrate temperature with illumination time. For the axial growth, excluding the initial transient growth, the same result as Bäuerle and his collaborators is derived. The influences of laser power and illumination time on the deposited diameter and height are found experimentally, and it is found that the derived theory agrees well with the experimental results.

  5. Femtosecond photoelectron point projection microscope

    SciTech Connect

    Quinonez, Erik; Handali, Jonathan; Barwick, Brett

    2013-10-15

    By utilizing a nanometer ultrafast electron source in a point projection microscope we demonstrate that images of nanoparticles with spatial resolutions of the order of 100 nanometers can be obtained. The duration of the emission process of the photoemitted electrons used to make images is shown to be of the order of 100 fs using an autocorrelation technique. The compact geometry of this photoelectron point projection microscope does not preclude its use as a simple ultrafast electron microscope, and we use simple analytic models to estimate temporal resolutions that can be expected when using it as a pump-probe ultrafast electron microscope. These models show a significant increase in temporal resolution when comparing to ultrafast electron microscopes based on conventional designs. We also model the microscopes spectroscopic abilities to capture ultrafast phenomena such as the photon induced near field effect.

  6. Simulated annealing with probabilistic analysis for solving traveling salesman problems

    NASA Astrophysics Data System (ADS)

    Hong, Pei-Yee; Lim, Yai-Fung; Ramli, Razamin; Khalid, Ruzelan

    2013-09-01

    Simulated Annealing (SA) is a widely used meta-heuristic that was inspired from the annealing process of recrystallization of metals. Therefore, the efficiency of SA is highly affected by the annealing schedule. As a result, in this paper, we presented an empirical work to provide a comparable annealing schedule to solve symmetric traveling salesman problems (TSP). Randomized complete block design is also used in this study. The results show that different parameters do affect the efficiency of SA and thus, we propose the best found annealing schedule based on the Post Hoc test. SA was tested on seven selected benchmarked problems of symmetric TSP with the proposed annealing schedule. The performance of SA was evaluated empirically alongside with benchmark solutions and simple analysis to validate the quality of solutions. Computational results show that the proposed annealing schedule provides a good quality of solution.

  7. Recent progress of quantum annealing

    SciTech Connect

    Suzuki, Sei

    2015-03-10

    We review the recent progress of quantum annealing. Quantum annealing was proposed as a method to solve generic optimization problems. Recently a Canadian company has drawn a great deal of attention, as it has commercialized a quantum computer based on quantum annealing. Although the performance of quantum annealing is not sufficiently understood, it is likely that quantum annealing will be a practical method both on a conventional computer and on a quantum computer.

  8. Impurity and defect interactions during laser thermal annealing in Ge

    NASA Astrophysics Data System (ADS)

    Milazzo, R.; Impellizzeri, G.; Piccinotti, D.; La Magna, A.; Fortunato, G.; De Salvador, D.; Carnera, A.; Portavoce, A.; Mangelinck, D.; Privitera, V.; Napolitani, E.

    2016-01-01

    The microscopic mechanisms involving dopants, contaminants, and defects in Ge during pulsed melting laser thermal annealing (LTA) are investigated in detail. Samples both un-implanted and implanted with As or B are processed by LTA as well as characterized in terms of chemical (1D and 3D), electrical, and strain profiling. The clustering of As is directly measured by 3D chemical profiling and correlated with its partial electrical activation along with a reduction of the lattice strain induced by As atoms. A semi-quantitative microscopic model involving the interaction with mobile As-vacancy (AsV) complexes is proposed to describe the clustering mechanism. Boron is shown to follow different clustering behavior that changes with depth and marked by completely different strain levels. Oxygen penetrates from the surface into all the samples as a result of LTA and, only in un-implanted Ge, it occupies an interstitial position inducing also positive strain in the lattice. On the contrary, data suggest that the presence of As or B forces O to assume different configurations with negligible strain, through O-V or O-B interactions for the two dopant species, respectively. These data suggest that LTA does not inject a significant amount of vacancies in Ge, at variance with Si, unless As atoms or possibly other n-type dopants are present. These results have to be carefully considered for modeling the LTA process in Ge and its implementation in technology.

  9. Evolution of nano-structures of silver due to rapid thermal annealing

    SciTech Connect

    Mondal, Shyamal Bhattacharyya, S. R.

    2014-04-24

    This report deals with rapid thermal annealing (RTA) effect on continuous silver film on Si(100) substrate. For this purpose silver films of different thicknesses were deposited and subsequently annealed at 500 and 800 °C. The as-deposited and annealed samples were investigated by scanning electron microscope (SEM). Formations of different nano-structures have been observed. Fragmentation of formed nanoislands also observed at temperature below melting temperature.

  10. Influence of Microscopic Diffusive Process on Uranyl Precipitation and Dissolution in Subsurface Sediments at Hanford Site, USA

    SciTech Connect

    Liu, Chongxuan; Zachara, John M.; McKinley, James P.; Wang, Zheming; Majors, Paul D.

    2004-03-29

    Uranium in DOE Hanford sediments was found to be distributed as uranyl silicate precipitates almost exclusively within interiors of sediment grains. The precipitates were minute, generally 1-3 {micro}m across in either radiating or parallel arrays in intraparticle microfractures of a few microns width and variable connectivity to particle surfaces. Grain-scale porosity, tortuosity and diffusivity of tracer (H2O) and U(VI) were measured and imaged using various spectroscopic techniques. Simulations using a microscopic reactive diffusion model suggested that diffusion-limited mass transport generated a favorable thermodynamic condition within the grain microfractures for precipitation and concentration of uranium from waste plumes. The rate and extent of uranyl precipitate dissolution were studied in various electrolytes with variable pH under ambient CO2 pressure. Uranium speciation and distribution before and after dissolution were monitored by spectroscopic and imaging techniques . Experimental, spectroscopic and modeling results collectively indicated that dissolution of uranyl precipitates was controlled by diffusion-limited dissolution kinetics.

  11. The importance of annealing 316 LVM stents.

    PubMed

    Meyer-Kobbe, C; Hinrichs, B H

    2003-01-01

    The annealing process is an important key step in the manufacture of high quality and reliable 316 LVM stents. [figure: see text] The methods commonly applied for verifying the outcome of the annealing process such as microhardness testing are inappropriate and should not be used. The tension testing of tubes, processed together with stents, provides reliable results of the final material properties of stents. During the course of the investigation the grain size was reduced significantly and the break elongation improved. The surface of the strain-tested material shows substantial improvements. All results are particularly important for thin-wall stents with filigree struts. PMID:12974121

  12. Note: Improving long-term stability of hot-wire anemometer sensors by means of annealing

    SciTech Connect

    Lundström, H.

    2015-08-15

    Annealing procedures for hot-wire sensors of platinum and platinum-plated tungsten have been investigated experimentally. It was discovered that the two investigated sensor metals behave quite differently during the annealing process, but for both types annealing may improve long-term stability considerably. Measured drift of sensors both without and with prior annealing is presented. Suggestions for suitable annealing temperatures and times are given.

  13. Learning quantum annealing

    NASA Astrophysics Data System (ADS)

    Behrman, Elizabeth; Steck, James

    We propose and develop a new quantum algorithm, whereby a quantum system can learn to anneal to a desired ground state. We demonstrate successful learning of entanglement for a two-qubit system, then bootstrap to larger systems. We also show that the method is robust to noise and decoherence.

  14. Quo Vadis quantum annealing?

    NASA Astrophysics Data System (ADS)

    Das, Arnab; Suzuki, Sei

    2015-02-01

    In this article we sketch a broad outline of quantum annealing as a framework for realizing analog quantum computation. We provide a short review of the basic ideas and discuss some issues relevant to the current scenario of condensed matter physics and quantum computation.

  15. On thermodynamic and microscopic reversibility

    SciTech Connect

    Crooks, Gavin E.

    2011-07-12

    The word 'reversible' has two (apparently) distinct applications in statistical thermodynamics. A thermodynamically reversible process indicates an experimental protocol for which the entropy change is zero, whereas the principle of microscopic reversibility asserts that the probability of any trajectory of a system through phase space equals that of the time reversed trajectory. However, these two terms are actually synonymous: a thermodynamically reversible process is microscopically reversible, and vice versa.

  16. Mechanical behaviors and failure processes of precracked specimens under uniaxial compression: A perspective from microscopic displacement patterns

    NASA Astrophysics Data System (ADS)

    Liu, Ting; Lin, Baiquan; Zou, Quanle; Zhu, Chuanjie; Yan, Fazhi

    2016-03-01

    Hydraulic slotting is an efficient permeability enhancement method that has been widely used in China for enhanced coalbed methane (ECBM) recovery. Although some research has been conducted on hydraulic slotting, the mechanical behaviors such as strength, deformation, and cracking processes of coal treated by this technique are still unclear. This paper numerically investigates the mechanical behaviors of specimens containing combined flaws with various inclination angles. Research results show that different flaw inclination angles result in variations in strength and deformation of precracked specimens. We also analyzed the crack initiation, propagation, and coalescence processes to understand the underlying mechanisms for the aforementioned variations. To evaluate the crack initiation and propagation process and its corresponding mechanisms, we proposed 12 types of displacement field modes from the perspective of particles relative motion. Based on this, evolution of the displacement field during loading process is analyzed and 11 types of crack and three types of crack initiation modes are extracted from the cracking processes of specimens with different inclination angles. Analysis of the displacement field not only indicates the type of each crack, but also reveals the formation mechanism of the three crack initiation modes. A comparison between the numerical results and the previous laboratory test results shows that numerical simulation can reproduce most of the phenomenon observed in the laboratory test. The research result is expected to contribute to the further understanding of the mechanical behavior of coal subjected to hydraulic slotting or the stability of rock structures.

  17. Thermal annealing of tilted fiber Bragg gratings

    NASA Astrophysics Data System (ADS)

    González-Vila, Á.; Rodríguez-Cobo, L.; Mégret, P.; Caucheteur, C.; López-Higuera, J. M.

    2016-05-01

    We report a practical study of the thermal decay of cladding mode resonances in tilted fiber Bragg gratings, establishing an analogy with the "power law" evolution previously observed on uniform gratings. We examine how this process contributes to a great thermal stability, even improving it by means of a second cycle slightly increasing the annealing temperature. In addition, we show an improvement of the grating spectrum after annealing, with respect to the one just after inscription, which suggests the application of this method to be employed to improve saturation issues during the photo-inscription process.

  18. SURFACE TEMPERATURE OF PROTOPLANETARY DISKS PROBED BY ANNEALING EXPERIMENTS REFLECTING SPITZER OBSERVATIONS

    SciTech Connect

    Roskosz, Mathieu; Gillot, Jessy; Leroux, Hugues; Capet, Frederic; Roussel, Pascal

    2009-12-20

    Pyroxenes and olivines are the dominant crystalline silicates observed in protoplanetary disks. Recent spectral observations from the Spitzer Space Telescope indicate that the abundance of olivine, generally associated with silica polymorphs, relative to pyroxene is higher in the outer cold part of the disk than in the inner warmer part. The interpretation of these unexpected results requires a comprehensive knowledge of the thermal processing of Mg-rich silicate dust. In this respect, amorphous analogs were thermally annealed to identify microscopic crystallization mechanisms. We show that pyroxenes are not produced in significant proportions below the glass transition temperature of the amorphous precursor. The annealing of amorphous enstatite leads to a mineralogical assemblage dominated by forsterite, with only minute amounts of pyroxenes at temperatures as high as the glass transition temperature of enstatite (1050 K). The decoupling of cation mobility in amorphous silicates, favors the crystallization of the most Mg-enriched silicates. These results are consistent with Spitzer observations of silicate dust and also with the documented mineralogy of presolar silicates, making the low-temperature annealing a likely formation process for these objects. Based on these laboratory experiments and Spitzer observations, it appears that the reported zoned mineralogy may directly records and calibrates the thermal gradient at the scale of protoplanetary disks.

  19. Surface Temperature of Protoplanetary Disks Probed by Annealing Experiments Reflecting Spitzer Observations

    NASA Astrophysics Data System (ADS)

    Roskosz, Mathieu; Gillot, Jessy; Capet, Frédéric; Roussel, Pascal; Leroux, Hugues

    2009-12-01

    Pyroxenes and olivines are the dominant crystalline silicates observed in protoplanetary disks. Recent spectral observations from the Spitzer Space Telescope indicate that the abundance of olivine, generally associated with silica polymorphs, relative to pyroxene is higher in the outer cold part of the disk than in the inner warmer part. The interpretation of these unexpected results requires a comprehensive knowledge of the thermal processing of Mg-rich silicate dust. In this respect, amorphous analogs were thermally annealed to identify microscopic crystallization mechanisms. We show that pyroxenes are not produced in significant proportions below the glass transition temperature of the amorphous precursor. The annealing of amorphous enstatite leads to a mineralogical assemblage dominated by forsterite, with only minute amounts of pyroxenes at temperatures as high as the glass transition temperature of enstatite (1050 K). The decoupling of cation mobility in amorphous silicates, favors the crystallization of the most Mg-enriched silicates. These results are consistent with Spitzer observations of silicate dust and also with the documented mineralogy of presolar silicates, making the low-temperature annealing a likely formation process for these objects. Based on these laboratory experiments and Spitzer observations, it appears that the reported zoned mineralogy may directly records and calibrates the thermal gradient at the scale of protoplanetary disks.

  20. Virtual pinhole confocal microscope

    SciTech Connect

    George, J.S.; Rector, D.M.; Ranken, D.M.; Peterson, B.; Kesteron, J.

    1999-06-01

    Scanned confocal microscopes enhance imaging capabilities, providing improved contrast and image resolution in 3-D, but existing systems have significant technical shortcomings and are expensive. Researchers at Los Alamos National Laboratory have developed a novel approach--virtual pinhole confocal microscopy--that uses state of the art illumination, detection, and data processing technologies to produce an imager with a number of advantages: reduced cost, faster imaging, improved efficiency and sensitivity, improved reliability and much greater flexibility. Work at Los Alamos demonstrated proof of principle; prototype hardware and software have been used to demonstrate technical feasibility of several implementation strategies. The system uses high performance illumination, patterned in time and space. The authors have built functional confocal imagers using video display technologies (LCD or DLP) and novel scanner based on a micro-lens array. They have developed a prototype system for high performance data acquisition and processing, designed to support realtime confocal imaging. They have developed algorithms to reconstruct confocal images from a time series of spatially sub-sampled images; software development remains an area of active development. These advances allow the collection of high quality confocal images (in fluorescence, reflectance and transmission modes) with equipment that can inexpensively retrofit to existing microscopes. Planned future extensions to these technologies will significantly enhance capabilities for microscopic imaging in a variety of applications, including confocal endoscopy, and confocal spectral imaging.

  1. Processing Technology in Microscopic Images of Cancer Cells in Pleural Fluid Based on Fuzzy Edge Detection Method

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Wang, Q. G.; Qi, J. P.

    2006-10-01

    The traditional manual method of cancer cell recognizing requests a long period of diagnoses. In order to improve the efficiency and veracity of diagnoses, this article applies technology of image processing to analysis and recognition of cancer cell image. This article uses the fuzzy edge extraction, which is based on the OTSU threshold to process the original image of the cancer cells in pleural fluid, and then extracts the feature of the cancer cells according to the morphology automatically. The experiment shows that features such as area rate of karyon and cytoplasm, karyon division, shape of karyon and so on will provide evidences for diagnoses and will improve the efficiency and veracity of diagnoses.

  2. Microscopic Analysis of Activated Sludge. Training Manual.

    ERIC Educational Resources Information Center

    Office of Water Program Operations (EPA), Cincinnati, OH. National Training and Operational Technology Center.

    This training manual presents material on the use of a compound microscope to analyze microscope communities, present in wastewater treatment processes, for operational control. Course topics include: sampling techniques, sample handling, laboratory analysis, identification of organisms, data interpretation, and use of the compound microscope.…

  3. BELL ANNEALING FURNACES, SHOWING EMPLOYEEDESIGN CENTER POST WITH THREE RADIAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    BELL ANNEALING FURNACES, SHOWING EMPLOYEE-DESIGN CENTER POST WITH THREE RADIAL ARMS FOR HANGING COILS. ANNEALING SOFTENS BATCHES OF COILS WHICH HAVE BEEN HARDENED BY ROLLING SO THAT THEY WILL BE SUITABLE FOR FURTHER PROCESSING. - American Brass Foundry, 70 Sayre Street, Buffalo, Erie County, NY

  4. Mechanical properties of ferrite-perlite and martensitic Fe-Mn-V-Ti-C steel processed by equal-channel angular pressing and high-temeperature annealing

    NASA Astrophysics Data System (ADS)

    Zakharova, G. G.; Astafurova, E. G.; Tukeeva, M. S.; Naidenkin, E. V.; Raab, G. I.; Dobatkin, S. V.

    2011-09-01

    Using the method of equal-channel angular pressing (ECAP), submicrocrystalline structure is formed in lowcarbon Fe-Mn-V-Ti-C steel with the average grain size 260 nm in the ferrite-perlite state and 310 nm in the martensitic state. It is established that the ECAP treatment gives rise to improved mechanical properties (Hμ = 2.9 GPa, σ0 = 990 MPa in the ferrite-perlite and Hμ = 3.7 GPa, σ0 = 1125 MPa in martensitic states), decreased plasticity, and results in plastic flow localization under tensile loading. The high strength properties formed by the ECAP are shown to sustain up to the annealing temperature 500°C.

  5. Effect of residual chips on the material removal process of the bulk metallic glass studied by in situ scratch testing inside the scanning electron microscope

    SciTech Connect

    Huang Hu; Zhao Hongwei; Shi Chengli; Wu Boda; Fan Zunqiang; Wan Shunguang; Geng Chunyang

    2012-12-15

    Research on material removal mechanism is meaningful for precision and ultra-precision manufacturing. In this paper, a novel scratch device was proposed by integrating the parasitic motion principle linear actuator. The device has a compact structure and it can be installed on the stage of the scanning electron microscope (SEM) to carry out in situ scratch testing. Effect of residual chips on the material removal process of the bulk metallic glass (BMG) was studied by in situ scratch testing inside the SEM. The whole removal process of the BMG during the scratch was captured in real time. Formation and growth of lamellar chips on the rake face of the Cube-Corner indenter were observed dynamically. Experimental results indicate that when lots of chips are accumulated on the rake face of the indenter and obstruct forward flow of materials, materials will flow laterally and downward to find new location and direction for formation of new chips. Due to similar material removal processes, in situ scratch testing is potential to be a powerful research tool for studying material removal mechanism of single point diamond turning, single grit grinding, mechanical polishing and grating fabrication.

  6. Hydrogen Annealing Of Single-Crystal Superalloys

    NASA Technical Reports Server (NTRS)

    Smialek, James L.; Schaeffer, John C.; Murphy, Wendy

    1995-01-01

    Annealing at temperature equal to or greater than 2,200 degrees F in atmosphere of hydrogen found to increase ability of single-crystal superalloys to resist oxidation when subsequently exposed to oxidizing atmospheres at temperatures almost as high. Supperalloys in question are principal constituents of hot-stage airfoils (blades) in aircraft and ground-based turbine engines; also used in other high-temperature applications like chemical-processing plants, coal-gasification plants, petrochemical refineries, and boilers. Hydrogen anneal provides resistance to oxidation without decreasing fatigue strength and without need for coating or reactive sulfur-gettering constituents. In comparison with coating, hydrogen annealing costs less. Benefits extend to stainless steels, nickel/chromium, and nickel-base alloys, subject to same scale-adhesion and oxidation-resistance considerations, except that scale is chromia instead of alumina.

  7. Simulation of Storm Occurrences Using Simulated Annealing.

    NASA Astrophysics Data System (ADS)

    Lokupitiya, Ravindra S.; Borgman, Leon E.; Anderson-Sprecher, Richard

    2005-11-01

    Modeling storm occurrences has become a vital part of hurricane prediction. In this paper, a method for simulating event occurrences using a simulated annealing algorithm is described. The method is illustrated using annual counts of hurricanes and of tropical storms in the Atlantic Ocean and Gulf of Mexico. Simulations closely match distributional properties, including possible correlations, in the historical data. For hurricanes, traditionally used Poisson and negative binomial processes also predict univariate properties well, but for tropical storms parametric methods are less successful. The authors determined that simulated annealing replicates properties of both series. Simulated annealing can be designed so that simulations mimic historical distributional properties to whatever degree is desired, including occurrence of extreme events and temporal patterning.

  8. Low frequency acoustic microscope

    DOEpatents

    Khuri-Yakub, Butrus T.

    1986-11-04

    A scanning acoustic microscope is disclosed for the detection and location of near surface flaws, inclusions or voids in a solid sample material. A focused beam of acoustic energy is directed at the sample with its focal plane at the subsurface flaw, inclusion or void location. The sample is scanned with the beam. Detected acoustic energy specularly reflected and mode converted at the surface of the sample and acoustic energy reflected by subsurface flaws, inclusions or voids at the focal plane are used for generating an interference signal which is processed and forms a signal indicative of the subsurface flaws, inclusions or voids.

  9. Atomic Force Microscope

    SciTech Connect

    Day, R.D.; Russell, P.E.

    1988-12-01

    The Atomic Force Microscope (AFM) is a recently developed instrument that has achieved atomic resolution imaging of both conducting and non- conducting surfaces. Because the AFM is in the early stages of development, and because of the difficulty of building the instrument, it is currently in use in fewer than ten laboratories worldwide. It promises to be a valuable tool for obtaining information about engineering surfaces and aiding the .study of precision fabrication processes. This paper gives an overview of AFM technology and presents plans to build an instrument designed to look at engineering surfaces.

  10. Solid state optical microscope

    DOEpatents

    Young, Ian T.

    1983-01-01

    A solid state optical microscope wherein wide-field and high-resolution images of an object are produced at a rapid rate by utilizing conventional optics with a charge-coupled photodiode array. A galvanometer scanning mirror, for scanning in one of two orthogonal directions is provided, while the charge-coupled photodiode array scans in the other orthogonal direction. Illumination light from the object is incident upon the photodiodes, creating packets of electrons (signals) which are representative of the illuminated object. The signals are then processed, stored in a memory, and finally displayed as a video signal.

  11. Solid state optical microscope

    DOEpatents

    Young, I.T.

    1983-08-09

    A solid state optical microscope wherein wide-field and high-resolution images of an object are produced at a rapid rate by utilizing conventional optics with a charge-coupled photodiode array. A galvanometer scanning mirror, for scanning in one of two orthogonal directions is provided, while the charge-coupled photodiode array scans in the other orthogonal direction. Illumination light from the object is incident upon the photodiodes, creating packets of electrons (signals) which are representative of the illuminated object. The signals are then processed, stored in a memory, and finally displayed as a video signal. 2 figs.

  12. Thermal Conductivity Changes in Titanium-Graphene Composite upon Annealing

    NASA Astrophysics Data System (ADS)

    Jagannadham, Kasichainula

    2016-02-01

    Ti-graphene composite films were prepared on polished Ti substrates by deposition of graphene platelets from suspension followed by deposition of Ti by magnetron sputtering. The films were annealed at different temperatures up to 1073 K (800 °C) and different time periods in argon atmosphere. The annealed films were characterized by X-ray diffraction for phase identification, scanning electron microscopy for microstructure, energy-dispersive spectrometry for chemical analysis, atomic force microscopy for surface roughness, and transient thermoreflectance for thermal conductivity and interface thermal conductance. The results showed that the interface between the composite film and Ti substrate remained continuous with the absence of voids. Oxygen concentration in the composite films has increased for higher temperature and time of annealing. TiO2 and TiC phases are formed only in the film annealed at 1073 K (800 °C). The thermal conductivity of the composite film decreased with increasing oxygen concentration. The effective thermal conductance of the film annealed at 1073 K (800 °C) was significantly lower. The interface thermal conductance between the composite film and the Ti substrate is also reduced for higher oxygen concentration. Formation of microscopic TiO2 phase bound by interface boundaries and oxygen incorporation is considered responsible for the lower thermal conductance of the Ti-graphene composite annealed at 1073 K (800 °C).

  13. Microscopic characteristic of biological iron sulfide composites during the generation process and the association with treatment effect on heavy metal wastewater.

    PubMed

    Yang, Yang; Xie, Yifei; Li, Xudong; Zhou, Jingchao; Liu, Jingwei

    2014-01-01

    Heavy metal pollution is a serious environmental concern worldwide, resulting in both environmental and human harm. Recently, studies have shown that environmental biotechnologies based on sulfate reduction offer a potential for removal of toxic heavy metals. Biological iron sulfide composites are iron sulfide compounds generated in situ by sulfate-reducing bacteria. In this study, microscopic morphological changes during the composites' generation process were studied, and the effect of biological iron sulfide composites in different generation phases on treatment of heavy metal wastewater was investigated to establish the correlation between macro-effect and micro-properties. The results revealed that the generation process of biological iron sulfide composites occurs in three phases: the formation phase, stationary phase, and agglomeration phase. The stationary phase can be divided into a pre-stationary phase and post-stationary phase. It was found that the best treatment time for Cr(6+) is in the pre-stationary phase, while the best treatment time for Cu(2+)and Cd(2+) is in the post-stationary phase. The results of this study further prove the benefits of treatment of heavy metal wastewater using biological sulfide composites and provide theoretical guidance in practical applications. PMID:25325556

  14. Annealing of hydrogen-induced defects in RF-plasma-treated Si wafers: ex situ and in situ transmission electron microscopy studies

    NASA Astrophysics Data System (ADS)

    Ghica, C.; Nistor, L. C.; Vizireanu, S.; Dinescu, G.

    2011-07-01

    The smart-cut™ process is based on inducing and processing structural defects below the free surface of semiconductor wafers. The necessary defects are currently induced by implantation of light elements such as hydrogen or helium. An alternative softer way to induce shallow subsurface defects is by RF-plasma hydrogenation. To facilitate the smart-cut process, the wafers containing the induced defects need to be subjected to an appropriate thermal treatment. In our experiments, (0 0 1) Si wafers are submitted to 200 and 50 W hydrogen RF-plasma and are subsequently annealed. The samples are studied by transmission electron microscopy (TEM), before and after annealing. The plasma-introduced defects are {1 1 1} and {1 0 0} planar-like defects and nanocavities, all of them involving hydrogen. Many nanocavities are aligned into strings almost parallel to the wafer surface. The annealing is performed either by furnace thermal treatment at 550 °C, or by in situ heating in the electron microscope at 450, 650 and 800 °C during the TEM observations. The TEM microstructural studies indicate a partial healing of the planar defects and a size increase of the nanometric cavities by a coalescence process of the small neighbouring nanocavities. By annealing, the lined up nanometric voids forming chains in the as-hydrogenated sample coalesced into well-defined cracks, mostly parallel to the wafer surface.

  15. Fabrication of a high-performance poly-Si thin-film transistor using a poly-Si film prepared by silicide-enhanced rapid thermal annealing process

    NASA Astrophysics Data System (ADS)

    Yang, Yong Ho; Ahn, Kyung Min; Kang, Seung Mo; Moon, Sun Hong; Ahn, Byung Tae

    2014-11-01

    A 50-nm thick polycrystalline Si film was fabricated by the crystallization of anamorphous Si film using silicide-enhanced rapid thermal annealing (SERTA). The amorphous Si film was deposited on a 5-nm thick polycrystalline Si seed layer containing nickel silicide precipitates in grain boundary areas. With the help of the silicide precipitates, the RTA temperature decreased from 730 to 680°C and the grain size of the crystallized polycrystalline Si film increased to 1.4 — 2.2 μm. Few defects were found within the grains and the Ni concentration in the polycrystalline film decreased to 1 × 1018 cm-3 due to the very-thin seed layer that contained nickel silicide precipitates. As a result, the field-effect hole mobility in the p-channel poly-Si thin film transistors (TFTs), fabricated employing the polycrystalline Si film, was as high as 169 cm2/V•s at a drain voltage of V D = -0.1 V; the subthreshold swing was as small as 0.24 V/decade. The minimum leakage current at V D= 5V was 1.5 × 10-10 A with very good diode characteristics. [Figure not available: see fulltext.

  16. Quasi in situ scanning force microscope with an automatic operated reaction chamber.

    PubMed

    Hund, Markus; Olszowka, Violetta; Fischer, Franz; Krejtschi, Heinz

    2011-11-01

    We describe the design and performance of a quasi in situ scanning force microscope with an automatic operated reaction chamber. The design provides a repetitive hermetically sealed sample environment for successive processing. The reaction chamber is based on a combination of a flexure-guided cover, a piezo-positioning system and a force applicator system. An axial force seals the cover against the reactor enabling flow-through applications at low pressure, ambient pressure, or elevated pressure. The position stability of the sample relative to the probe is characterized and a full automated operation of the instrument is explored by the alignment of an ABC terblock copolymer thin film undergoing solvent vapor annealing in the presence of a high electric field. Due to the high electric field strength and the sharp scanning force microscope tip it is impossible to perform in situ scanning in the presence of the electric field. PMID:22128986

  17. Annealing Mechanism and Effect of Microwave Plasma Assisted Annealing on Properties of Sputtered Pb(Zr0.52Ti0.48)O3 Thin Films.

    PubMed

    Wan, Jing; Yang, Chengtao; He, Ming

    2016-03-01

    To solve some problems existing in PZT films, such as: large residual stresses, interface diffusion, and lead loss, etc., which were caused by high post-annealing temperatures, and to obtain thin films with high-preferred orientation and uniform size grain and dense microstructure, different technological conditions of microwave plasma assisted post-annealing had been pilot studied. X-ray diffraction was used to analyze the crystal structures of the films. Transmission electronic microscope was used to analyze the surface and the interface morphology of the films. Ferroelectric properties were showed by measuring the remnant polarization and the leakage current dependence of electric field. The results indicated that it was good for reducing lead loss and annealing temperature of PZT films by microwave plasma assisted annealing. Ferroelectric properties of the film could also be enhanced by this pilot annealing method. PMID:27455722

  18. Microscopic Tribotactic Walkers

    NASA Astrophysics Data System (ADS)

    Steimel, Joshua; Aragones, Juan; Alexander-Katz, Alfredo

    2014-03-01

    The translational motion of a rotating object near a surface is strongly dependent on the friction between the object and the surface. The process of friction is inherently directional and the friction coefficient can be anisotropic even in the absence of a net friction coefficient gradient. This is macroscopically observed in the ordering motif of some animal hair or scales and a microscopic analog can be imagined where the friction coefficient is determined by the strength and density of reversible bonds between a rotating object and the substrate. For high friction coefficients most of the rotational motion is converted into translational motion; conversely for low friction coefficients the object primarily rotates in place. We exploited this property to design and test a new class of motile system that displays tribotaxis, which is the process by which an object detects differences in the local friction coefficient and moves accordingly either to regions of higher or lower friction. These synthetic tribotactic microscopic walkers, composed of a pair of functionalized superparamagnetic beads, detect gradients in the spatial friction coefficient and migrate towards high friction areas when actuated in a random fashion. The effective friction between the walkers and the substrate is controlled by the local density of active receptors in the substrate. The tribotactic walkers also displayed trapping in high friction areas where the density of free receptors is higher.

  19. Microscopic analysis of 10,11Be elastic scattering on protons and 12C and breakup processes of 11Be within the 10Be+n cluster model

    NASA Astrophysics Data System (ADS)

    Spasova, K.; Lukyanov, V. K.; Kadrev, D. N.; Antonov, A. N.; Zemlyanaya, E. V.; Lukyanov, K. V.; Gaidarov, M. K.

    2016-06-01

    The elastic scattering cross-sections of 10,11Be on protons and 12C at energy E < 100 MeV/nucleon using microscopically calculated optical potentials (OP) are presented. The real OP is obtained by a folding procedure with effective NN interactions, while the imaginary OP is estimated within the high energy approximation (HEA). The spin-orbit part of the OP is also included. The characteristics of the breakup processes of 11Be on different nuclear targets are also considered. The cross-sections of diffractive breakup and stripping reactions of 11Be on 9Be, 93Nb, 181Ta and 238U at energy E = 63 MeV/nucleon and the longitudinal momentum distributions of 10Be fragments produced in the breakup of 11Be on these nuclei are presented. The results are in a good agreement with the available experimental data, in particular the obtained widths of about 50 MeV/c are closed to the empirical ones.

  20. The Scanning Optical Microscope.

    ERIC Educational Resources Information Center

    Sheppard, C. J. R.

    1978-01-01

    Describes the principle of the scanning optical microscope and explains its advantages over the conventional microscope in the improvement of resolution and contrast, as well as the possibility of producing a picture from optical harmonies generated within the specimen.

  1. Advanced Microscopic Integrated Thermocouple Arrays

    NASA Technical Reports Server (NTRS)

    Pettigrew, Penny J.

    1999-01-01

    The purpose of this research is to develop and refine a technique for making microscopic thermocouple arrays for use in measuring the temperature gradient across a solid-liquid interface during the solidification process. Current thermocouple technology does not allow for real-time measurements across the interface due to the prohibitive size of available thermocouples. Microscopic thermocouple arrays will offer a much greater accuracy and resolution of temperature measurements across the solid-liquid interface which will lead to a better characterization of the solidification process and interface reaction which affect the properties of the resulting material.

  2. Spectral and kinetic characterization of CaS:Pr 3+ phosphor synthesized through chemical co-precipitation route and post annealing process

    NASA Astrophysics Data System (ADS)

    Pitale, Shreyas S.; Sharma, Suchinder K.; Dubey, R. N.; Qureshi, M. S.; Malik, M. M.

    2010-01-01

    Synthesis of Pr 3+ doped CaS phosphor has been reported through chemical co-precipitation route and post annealing in the presence of NaCl, KCl and NH 4Cl flux. Good crystallinity and cubic CaS phase is achieved after post-precipitation calcinations of powder at 900 °C for 1 h duration. Pseudo-spherical morphostructural features of micron-size particles are observed for phosphor prepared via chemical route. Phosphor samples are also prepared via solid-state carbothermal reduction technique for comparative studies and exhibit dendrite like structures. Prominent excitation bands at 276, 320 nm are observed for the present phosphor samples. The emission spectra show a duo-band feature at 495 and 580 nm where a spectral overlap of host lattice emission due to intrinsic defects and characteristic spectral features of Pr ion due to 3P 0- 1H 4, 3P 1- 1H 5, 1D 2- 3H 4 and 3P 0- 3F 2 transitions can be observed. The carbothermal route synthesized CaS:Pr shows spectral features of Pr ion due to 3P 0- 1H 4 and 3P 0- 3F j transitions. Electron spin resonance investigations reveal the presence of unintentional Mn 2+ through a sextet signature. F + electron trapping center is detected having g = 2.0034. Thermoluminescence glow curves possess a broad duo-band feature between room temperature -100 °C and >125 °C under host UV irradiation. Kinetic characterization using glow curve deconvolution reveals quasicontinuous distribution of traps having energy between 0.56 and 1.15 eV and frequency factors between 10 7 and 10 11/sec.

  3. TEAM Electron Microscope Animation

    SciTech Connect

    2012-01-01

    The TEAM Electron Microscope, a device that enables atomic-scale imaging in 3-D, has a rotating stage that can hold and position samples inside electron microscopes with unprecedented stability, position-control accuracy, and range of motion.The TEAM Stage makes one of the world's most powerful electron microscopes even better, and enables previously impossible experiments.

  4. Deformation and annealing response of TD-nickel chromium sheet

    NASA Technical Reports Server (NTRS)

    Kane, R. D.; Ebert, L. J.

    1973-01-01

    The deformation and annealing response of TD-nickel chromium (TD-NiCr) 0.1 inch thick sheet was examined using various cold-rolling and annealing treatments. Upon annealing (above 816 C (1500 F), the as-received material was converted from an initially ultra-fine grain size (average grain dimension 0.51 micron) to a large grain structure. Increases in grain size by a factor of 100 to 200 were observed for this transformation. However, in those material states where the large grain transformation was absent, a fine grain recrystallized structure formed upon annealing (above 732 C (1350 F)). The deformation and annealing response of TD-NiCr sheet was evaluated with respect to the processing related variables as mode and severity of deformation and annealing temperature. Results indicate that the large grain transformation, classical primary recrystallization occurs. Using selected materials produced during the deformation and annealing study, the elevated temperature tensile properties of TD-NiCr sheet were examined in the temperature range 593 C (1100 F) to 1093 C (2000 F). It was observed that the elevated temperature tensile properties of TD-NiCr sheet could be optimized by the stabilization of a large grain size in this material using the cold working and/or annealing treatments developed during the present investigation.

  5. Mechanical annealing and source-limited deformation in submicrometre-diameter Ni crystals.

    PubMed

    Shan, Z W; Mishra, Raja K; Syed Asif, S A; Warren, Oden L; Minor, Andrew M

    2008-02-01

    The fundamental processes that govern plasticity and determine strength in crystalline materials at small length scales have been studied for over fifty years. Recent studies of single-crystal metallic pillars with diameters of a few tens of micrometres or less have clearly demonstrated that the strengths of these pillars increase as their diameters decrease, leading to attempts to augment existing ideas about pronounced size effects with new models and simulations. Through in situ nanocompression experiments inside a transmission electron microscope we can directly observe the deformation of these pillar structures and correlate the measured stress values with discrete plastic events. Our experiments show that submicrometre nickel crystals microfabricated into pillar structures contain a high density of initial defects after processing but can be made dislocation free by applying purely mechanical stress. This phenomenon, termed 'mechanical annealing', leads to clear evidence of source-limited deformation where atypical hardening occurs through the progressive activation and exhaustion of dislocation sources. PMID:18157134

  6. Microscope and method of use

    DOEpatents

    Bongianni, Wayne L.

    1984-01-01

    A method and apparatus for electronically focusing and electronically scanning microscopic specimens are given. In the invention, visual images of even moving, living, opaque specimens can be acoustically obtained and viewed with virtually no time needed for processing (i.e., real time processing is used). And planar samples are not required. The specimens (if planar) need not be moved during scanning, although it will be desirable and possible to move or rotate nonplanar specimens (e.g., laser fusion targets) against the lens of the apparatus. No coupling fluid is needed, so specimens need not be wetted. A phase acoustic microscope is also made from the basic microscope components together with electronic mixers.

  7. Microscope and method of use

    DOEpatents

    Bongianni, W.L.

    1984-04-17

    A method and apparatus for electronically focusing and electronically scanning microscopic specimens are given. In the invention, visual images of even moving, living, opaque specimens can be acoustically obtained and viewed with virtually no time needed for processing (i.e., real time processing is used). And planar samples are not required. The specimens (if planar) need not be moved during scanning, although it will be desirable and possible to move or rotate nonplanar specimens (e.g., laser fusion targets) against the lens of the apparatus. No coupling fluid is needed, so specimens need not be wetted. A phase acoustic microscope is also made from the basic microscope components together with electronic mixers. 7 figs.

  8. Microscopic processes in space plasmas and their role in macroscale phenomena. Proceedings. D0.2 Symposium of COSPAR Scientific Commission D held during the 32nd COSPAR Scientific Assembly, Nagoya (Japan), 12 - 19 Jul 1998.

    NASA Astrophysics Data System (ADS)

    The following topics were dealt with: microscopic plasma processes, wave generation, particle acceleration and heating, bow shock, magnetic reconnection, spacecraft observations, magnetospheric plasma dynamics, temporal and spatial variations of the magnetosphere, theoretical and computational studies of macroscale phenomena, specific forms of particle distribution functions, temperature anisotropy and nongyrotropy.

  9. High mobility annealing of Transparent Conductive Oxides

    NASA Astrophysics Data System (ADS)

    Warzecha, M.; Owen, J. I.; Wimmer, M.; Ruske, F.; Hotovy, J.; Hüpkes, J.

    2012-04-01

    To improve electrical properties a high temperature annealing treatment was applied to several transparent conductive oxides (TCO), namely tin doped indium oxide (ITO), Ga- or Al- doped ZnO (ZnO:Al/Ga), ion beam assisted deposited (IBAD) ZnO:Ga and Ga doped zinc magnesium oxide (ZnMgO:Ga). All these films were grown by magnetron sputtering. During the annealing process all TCO films were capped with 50 nm of amorphous silicon in order to protect the films from environmental impact. Increase in mobility up to 72 cm2/Vs and low resistivity of 1.6 × 10-4 Ωcm was achieved for ZnO:Al after annealing at 650°C for 24 h. Independent of the deposition conditions and doping or alloying material almost all ZnO based films show a consistent improvement in mobility. Also for ITO films a decrease in resistivity with partially improved mobility was found after annealing. However, not all ITO films show consistent improvement, but carrier density above 1021 cm-3 while ZnO films show no clear trend for carrier density but a remarkable increase in mobility. Thus we propose the healing of defects and the activation of donors to be most significant effects for ZnO and ITO films, respectively.

  10. Mars Under the Microscope

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This magnified look at the martian soil near the Mars Exploration Rover Opportunity's landing site, Meridiani Planum, shows coarse grains sprinkled over a fine layer of sand. The image was captured by the rover's microscopic imager on the 10th day, or sol, of its mission. Scientists are intrigued by the spherical rocks, which can be formed by a variety of geologic processes, including cooling of molten lava droplets and accretion of concentric layers of material around a particle or 'seed.'

    The examined patch of soil is 3 centimeters (1.2 inches) across. The circular grain in the lower left corner is approximately 3 millimeters (.12 inches) across, or about the size of a sunflower seed.

  11. Embrittlement recovery due to annealing of reactor pressure vessel steels

    SciTech Connect

    Eason, E.D.; Wright, J.E.; Nelson, E.E.; Odette, G.R.; Mader, E.V.

    1996-03-01

    Embrittlement of reactor pressure vessels (RPVs) can be reduced by thermal annealing at temperatures higher than the normal operating conditions. Although such an annealing process has not been applied to any commercial plants in the United States, one US Army reactor, the BR3 plant in Belgium, and several plants in eastern Europe have been successfully annealed. All available Charpy annealing data were collected and analyzed in this project to develop quantitative models for estimating the recovery in 30 ft-lb (41 J) Charpy transition temperature and Charpy upper shelf energy over a range of potential annealing conditions. Pattern recognition, transformation analysis, residual studies, and the current understanding of the mechanisms involved in the annealing process were used to guide the selection of the most sensitive variables and correlating parameters and to determine the optimal functional forms for fitting the data. The resulting models were fitted by nonlinear least squares. The use of advanced tools, the larger data base now available, and insight from surrogate hardness data produced improved models for quantitative evaluation of the effects of annealing. The quality of models fitted in this project was evaluated by considering both the Charpy annealing data used for fitting and the surrogate hardness data base. The standard errors of the resulting recovery models relative to calibration data are comparable to the uncertainty in unirradiated Charpy data. This work also demonstrates that microhardness recovery is a good surrogate for transition temperature shift recovery and that there is a high level of consistency between the observed annealing trends and fundamental models of embrittlement and recovery processes.

  12. Inverted low band gap polymer solar cells integrated with a low-temperature-annealed sol-gel-derived ZnO: Active layer thickness effect on the recombination process

    NASA Astrophysics Data System (ADS)

    Dhibi, O.; Ltaief, A.; Zghal, S.; Bouazizi, A.

    2013-08-01

    Structural of thin film of ZnO elaborated by sol-gel ZnO method, annealed at different temperatures were investigated by means of Photoluminescence and Raman spectroscopy analysis. The results show the formation of crystalline layer of ZnO after annealing at 150 °C. This thin film provided an effective hole blocking layer and an increased interfacial area for electron collection. Inverted bulk heterojunction organic solar cells were fabricated using ZnO film as the electron collecting layer. The influence of spin coating speed of the active layer on the performance of inverted-type organic solar cells has been investigated. The organic photoactive layers consisted of Poly[N-9‧-heptadecanyl-2,7-carbazole-alt-5,5-(4‧,7‧-di-2-thienyl-2‧,1‧,3‧-benzothiadiazole)] (PCDTBT) and [6,6]-Phenyl-C71-butyric acid methyl ester (PC70BM) were spin coated onto ZnO thin film with two spin coating speeds at 600 and 2000 rpm. Experimental results showed that the short-circuit current density (Jsc), the fill factor (FF) and power conversion efficiency (PCE) increase with increasing spin coating speed. This result may be attributed to reducing series resistance and recombination processes in thinner photoactive layer. The impedance spectra of the devices were measured under illumination. A decrease in the charge recombination and the resistance of whole device were observed with the increase in the spin coating speed of the active layer.

  13. Nanometer-scale characterization of SiO2/Si with a scanning capacitance microscope

    NASA Astrophysics Data System (ADS)

    Tomiye, Hideto; Yao, Takafumi; Kawami, Hiroshi; Hayashi, Tsukasa

    1996-12-01

    A novel scanning capacitance microscope (SCaM) is developed using a tungsten stylus as a cantilever. The deflection of the cantilever is detected by projecting the cantilever onto a photodetector. A combined SCaM, atomic force microscope (AFM), and scanning tunneling microscope has been constructed. The spatial resolution for SCaM measurements is estimated to be less than 100 nm. Local electrical properties of a SiO2/Si system are investigated using the SCaM and AFM functions of the combined microscope. A lateral p-n junction is formed, by ion implantation of P into a lightly B-doped Si wafer, the structure is then annealed and thermally oxidized. It is demonstrated that (1) the p-n junction can be observed even through the oxide layer, (2) the local impurity concentration can be estimated from capacitance-voltage (C-V) characteristics, and (3) P diffuses into the B-doped region during the thermal processes.

  14. Fullerene formation and annealing

    SciTech Connect

    Mintmire, J.W.

    1996-04-05

    Why does the highly symmetric carbon cluster C{sub 60} form in such profusion under the right conditions? This question was first asked in 1985, when Kroto suggested that the predominance of the C{sub 60} carbon clusters observed in the molecular beam experiments could be explained by the truncated icosahedral (or soccer ball) form. The name given to this cluster, buckminsterfullerene, led to the use of the term fullerenes for the family of hollow-cage carbon clusters made up of even numbers of triply coordinated carbons arranged with 12 pentagonal rings and an almost arbitrary number of hexagonal rings. More than a decade later, we still lack a completely satisfying understanding of the fundamental chemistry that takes place during fullerene formation. Most current models for fullerene formation require a facile mechanism for ring rearrangement in the fullerene structure, but the simplest proposed mechanisms are believed to have unrealistically high activation barriers. In recent research calculations have suggested that atomic carbon in the reaction mixture could act as a catalyst and allow substantially lower activation barriers for fullerene annealing. This article discusses the background for this research and other adjunct research. 14 refs.

  15. Reactor vessel annealing system

    DOEpatents

    Miller, Phillip E.; Katz, Leonoard R.; Nath, Raymond J.; Blaushild, Ronald M.; Tatch, Michael D.; Kordalski, Frank J.; Wykstra, Donald T.; Kavalkovich, William M.

    1991-01-01

    A system for annealing a vessel (14) in situ by heating the vessel (14) to a defined temperature, composed of: an electrically operated heater assembly (10) insertable into the vessel (14) for heating the vessel (14) to the defined temperature; temperature monitoring components positioned relative to the heater assembly (10) for monitoring the temperature of the vessel (14); a controllable electric power supply unit (32-60) for supplying electric power required by the heater assembly (10); a control unit (80-86) for controlling the power supplied by the power supply unit (32-60); a first vehicle (2) containing the power supply unit (32-60); a second vehicle (4) containing the control unit (80-86); power conductors (18,22) connectable between the power supply unit (32-60) and the heater unit (10) for delivering the power supplied by the power supply unit (32-60) to the heater assembly (10); signal conductors (20,24) connectable between the temperature monitoring components and the control unit (80-86) for delivering temperature indicating signals from the temperature monitoring components to the control unit (80-86); and control conductors (8) connectable between the control unit (80-86) and the power supply unit (32-60) for delivering to the power supply unit (32-60) control signals for controlling the level of power supplied by the power supply unit (32-60) to the heater assembly (10).

  16. Single crystalline graphene synthesized by thermal annealing of humic acid over copper foils

    NASA Astrophysics Data System (ADS)

    Beall, Gary W.; Duraia, El-Shazly M.; Yu, Q.; Liu, Z.

    2014-02-01

    Production of graphene by thermal annealing on copper foil substrates has been studied with different sources of carbon. The three carbon sources include humic acid derived from leonardite, graphenol, and activated charcoal. Hexagonal single crystalline graphene has been synthesized over the copper foil substrates by thermal annealing of humic acid, derived from leonardite, in argon and hydrogen atmosphere (Ar/H2=20). The annealing temperature was varied between 1050 °C and 1100 °C at atmospheric pressure. Samples have been investigated using scanning electron microscope (SEM) and Raman spectroscopy. At lower temperatures the thermal annealing of the three carbon sources used in this study produces pristine graphene nanosheets which cover almost the whole substrate. However when the annealing temperature has been increased up to 1100 °C, hexagonal single crystalline graphene have been observed only in the case of the humic acid. Raman analysis showed the existence of 2D band around 2690 cm-1.

  17. Excimer laser annealing for low-voltage power MOSFET

    NASA Astrophysics Data System (ADS)

    Chen, Yi; Okada, Tatsuya; Noguchi, Takashi; Mazzamuto, Fulvio; Huet, Karim

    2016-08-01

    Excimer laser annealing of lumped beam was performed to form the P-base junction for high-performance low-voltage-power MOSFET. An equivalent shallow-junction structure for the P-base junction with a uniform impurity distribution is realized by adopting excimer laser annealing (ELA). The impurity distribution in the P-base junction can be controlled precisely by the irradiated pulse energy density and the number of shots of excimer laser. High impurity activation for the shallow junction has been confirmed in the melted phase. The application of the laser annealing technology in the fabrication process of a practical low-voltage trench gate MOSFET was also examined.

  18. Effects of vacuum annealing treatment on microstructures and residual stress of AlSi10Mg parts produced by selective laser melting process

    NASA Astrophysics Data System (ADS)

    Chen, Tian; Wang, Linzhi; Tan, Sheng

    2016-07-01

    Selective laser melting (SLM)-fabricated AlSi10Mg parts were heat-treated under vacuum to eliminate the residual stress. Microstructure evolutions and tensile properties of the SLM-fabricated parts before and after vacuum annealing treatment were studied. The results show that the crystalline structure of SLM-fabricated AlSi10Mg part was not modified after the vacuum annealing treatment. Additionally, the grain refinement had occurred after the vacuum annealing treatment. Moreover, with increasing of the vacuum annealing time, the second phase increased and transformed to spheroidization and coarsening. The SLM-produced parts after vacuum annealing at 300∘C for 2 h had the maximum ultimate tensile strength (UTS), yield strength (YS) and elongation, while the elastic modulus decreased significantly. In addition, the tensile residual stress was found in the as-fabricated AlSi10Mg samples by the microindentation method.

  19. The evolution of microstructure and photoluminescence of SiCN films with annealing temperature

    SciTech Connect

    Du Xiwen; Fu Yang; Sun Jing; Yao Pei

    2006-05-01

    Silicon carbonitride (SiCN) films were deposited by radio-frequency magnetron sputtering and then annealed at different temperatures from 1100 to 1300 deg. C in hydrogen atmosphere. The as-deposited films and films annealed at 1100 deg. C did not show photoluminescence (PL), whereas strong PL peaks appeared at 355 and 469 nm after annealing at 1200 and 1300 deg. C. X-ray diffraction, transmission electron microscope, and Fourier transform infrared spectrometer results show that the enhancement of PL properties is due to the change of microstructure and composition.

  20. Cryogenic immersion microscope

    DOEpatents

    Le Gros, Mark; Larabell, Carolyn A.

    2010-12-14

    A cryogenic immersion microscope whose objective lens is at least partially in contact with a liquid reservoir of a cryogenic liquid, in which reservoir a sample of interest is immersed is disclosed. When the cryogenic liquid has an index of refraction that reduces refraction at interfaces between the lens and the sample, overall resolution and image quality are improved. A combination of an immersion microscope and x-ray microscope, suitable for imaging at cryogenic temperatures is also disclosed.

  1. Recurrence tracking microscope

    SciTech Connect

    Saif, Farhan

    2006-03-15

    In order to probe nanostructures on a surface we present a microscope based on the quantum recurrence phenomena. A cloud of atoms bounces off an atomic mirror connected to a cantilever and exhibits quantum recurrences. The times at which the recurrences occur depend on the initial height of the bouncing atoms above the atomic mirror, and vary following the structures on the surface under investigation. The microscope has inherent advantages over existing techniques of scanning tunneling microscope and atomic force microscope. Presently available experimental technology makes it possible to develop the device in the laboratory.

  2. Birefringence simulation of annealed ingot of calcium fluoride single crystal

    NASA Astrophysics Data System (ADS)

    Ogino, H.; Miyazaki, N.; Mabuchi, T.; Nawata, T.

    2008-01-01

    We developed a method for simulating birefringence of an annealed ingot of calcium fluoride single crystal caused by the residual stress after annealing process. The method comprises the heat conduction analysis that provides the temperature distribution during the ingot annealing, the elastic thermal stress analysis using the assumption of the stress-free temperature that provides the residual stress after annealing, and the birefringence analysis of an annealed ingot induced by the residual stress. The finite element method was applied to the heat conduction analysis and the elastic thermal stress analysis. In these analyses, the temperature dependence of material properties and the crystal anisotropy were taken into account. In the birefringence analysis, the photoelastic effect gives the change of refractive indices, from which the optical path difference in the annealed ingot is calculated by the Jones calculus. The relation between the Jones calculus and the approximate method using the stress components averaged along the optical path is discussed theoretically. It is found that the result of the approximate method agrees very well with that of the Jones calculus in birefringence analysis. The distribution pattern of the optical path difference in the annealed ingot obtained from the present birefringence calculation methods agrees reasonably well with that of the experiment. The calculated values also agree reasonably well with those of the experiment, when a stress-free temperature is adequately selected.

  3. Method and apparatus for selectively annealing heterostructures using microwave

    NASA Technical Reports Server (NTRS)

    Atwater, Harry A. (Inventor); Brain, Ruth A. (Inventor); Barmatz, Martin B. (Inventor)

    1998-01-01

    The present invention discloses a process for selectively annealing heterostructures using microwaves. A heterostructure, comprised of a material having higher microwave absorption and a material having lower microwave absorption, is exposed to microwaves in the cavity. The higher microwave absorbing material absorbs the microwaves and selectively heats while the lower microwave absorbing material absorbs small amounts of microwaves and minimally heats. The higher microwave absorbing material is thereby annealed onto the less absorbing material which is thermally isolated.

  4. Method and apparatus for selectively annealing heterostructures using microwaves

    NASA Technical Reports Server (NTRS)

    Atwater, Harry A. (Inventor); Brain, Ruth A. (Inventor); Barmatz, Martin B. (Inventor)

    1998-01-01

    The present invention discloses a process for selectively annealing heterostructures using microwaves. A heterostructure, comprised of a material having higher microwave absorption and a material having lower microwave absorption, is exposed to microwaves in the cavity. The higher microwave absorbing material absorbs the microwaves and selectively heats while the lower microwave absorbing material absorbs small amounts of microwaves and minimally heats. The higher microwave absorbing material is thereby annealed onto the less absorbing material which is thermally isolated.

  5. A guided simulated annealing method for crystallography.

    PubMed

    Chou, C I; Lee, T K

    2002-01-01

    A new optimization algorithm, the guided simulated annealing method, for use in X-ray crystallographic studies is presented. In the traditional simulated annealing method, the search for the global minimum of a cost function is only determined by the ratio of energy change to the temperature. This method designs a new quality function to guide the search for a minimum. Using a multiresolution process, the method is much more efficient in finding the global minimum than the traditional method. Results for two large molecules, isoleucinomycin (C(60)H(102)N(6)O(18)) and an alkyl calix (C(72)H(112)O(8). 4C(2)H(6)O), with different space groups are reported. PMID:11752762

  6. Mathematical foundation of quantum annealing

    SciTech Connect

    Morita, Satoshi; Nishimori, Hidetoshi

    2008-12-15

    Quantum annealing is a generic name of quantum algorithms that use quantum-mechanical fluctuations to search for the solution of an optimization problem. It shares the basic idea with quantum adiabatic evolution studied actively in quantum computation. The present paper reviews the mathematical and theoretical foundations of quantum annealing. In particular, theorems are presented for convergence conditions of quantum annealing to the target optimal state after an infinite-time evolution following the Schroedinger or stochastic (Monte Carlo) dynamics. It is proved that the same asymptotic behavior of the control parameter guarantees convergence for both the Schroedinger dynamics and the stochastic dynamics in spite of the essential difference of these two types of dynamics. Also described are the prescriptions to reduce errors in the final approximate solution obtained after a long but finite dynamical evolution of quantum annealing. It is shown there that we can reduce errors significantly by an ingenious choice of annealing schedule (time dependence of the control parameter) without compromising computational complexity qualitatively. A review is given on the derivation of the convergence condition for classical simulated annealing from the view point of quantum adiabaticity using a classical-quantum mapping.

  7. Effect of annealing in a various oxygen atmosphere on structural, optical, electrical and gas sensing properties of MoxOy thin films

    NASA Astrophysics Data System (ADS)

    Arfaoui, A.; Ouni, B.; Touihri, S.; Mhamdi, A.; Labidi, A.; Manoubi, T.

    2015-07-01

    Molybdenum oxide thin films were thermally evaporated on a glass substrate and monitored by an annealing process in a variable oxygen atmosphere. The effects of post annealing condition on the microstructural, morphological, optical and electrical properties were investigated using X-ray diffraction, Raman spectroscopy, atomic force microscope, spectroscopic ellipsometry and impedance spectroscopy. As-deposited amorphous films crystallized into tetragonal metastable phase of Mo5O14 on annealing at 500 °C in vacuum and air. This structure transformed to stable orthorhombic of MoO3 with annealing in oxygen environment. The optical parameters such as the refractive index, extinction coefficient, optical band gap energy and the Urbach energy were calculated from Cauchy formalism. Ellipsometric measurements reveal that the samples present optical gap located between 3.24 and 3.90 eV when the atmosphere becomes rich on oxygen. The variation of the conductivity in terms of the temperature shows an electrical behavior with oxygen environment. Finally, it has been found that MoO3 thin films had high sensitivity to ethanol, which made them as a good candidate for the ethanol sensor.

  8. Mailing microscope slides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many insects feed agriculturally important crops, trees, and ornamental plants and cause millions of dollars of damage annually. Identification for some of these require the preparation of a microscope slide for examination. There are times when a microscope slide may need to be sent away to a speci...

  9. The Light Microscope.

    ERIC Educational Resources Information Center

    Baker, W. L.

    1995-01-01

    Describes the function of the various parts of the microscope and their integration in the formation of an optical image. Presents a procedure for setting up a microscope to obtain maximum resolution and contrast for each objective lens at all magnifications. (JRH)

  10. Photography through the Microscope.

    ERIC Educational Resources Information Center

    McNeil, D. W.

    1992-01-01

    Describes how to illuminate and optically stain slides for microscope use and how to interface a 35mm camera with a microscope using an adaptor. Provides equipment descriptions and sources, details about illumination, image formation, darkfield adaptors, centerable filter adaptors, darkfield stops, rheinburg filters, and choosing specimens to…

  11. The Homemade Microscope.

    ERIC Educational Resources Information Center

    Baker, Roger C., Jr.

    1991-01-01

    Directions for the building of a pocket microscope that will make visible the details of insect structure and living bacteria are described. Background information on the history of microscopes and lenses is provided. The procedures for producing various types of lenses are included. (KR)

  12. Surface imaging microscope

    NASA Astrophysics Data System (ADS)

    Rogala, Eric W.; Bankman, Isaac N.

    2008-04-01

    The three-dimensional shapes of microscopic objects are becoming increasingly important for battlespace CBRNE sensing. Potential applications of microscopic 3D shape observations include characterization of biological weapon particles and manufacturing of micromechanical components. Aerosol signatures of stand-off lidar systems, using elastic backscatter or polarization, are dictated by the aerosol particle shapes and sizes that must be well characterized in the lab. A low-cost, fast instrument for 3D surface shape microscopy will be a valuable point sensor for biological particle sensing applications. Both the cost and imaging durations of traditional techniques such as confocal microscopes, atomic force microscopes, and electron scanning microscopes are too high. We investigated the feasibility of a low-cost, fast interferometric technique for imaging the 3D surface shape of microscopic objects at frame rates limited only by the camera in the system. The system operates at two laser wavelengths producing two fringe images collected simultaneously by a digital camera, and a specialized algorithm we developed reconstructs the surface map of the microscopic object. The current implementation assembled to test the concept and develop the new 3D reconstruction algorithm has 0.25 micron resolution in the x and y directions, and about 0.1 micron accuracy in the z direction, as tested on a microscopic glass test object manufactured with etching techniques. We describe the interferometric instrument, present the reconstruction algorithm, and discuss further development.

  13. Forming an age hardenable aluminum alloy with intermediate annealing

    NASA Astrophysics Data System (ADS)

    Wang, Kaifeng; Carsley, John E.; Stoughton, Thomas B.; Li, Jingjing; Zhang, Lianhong; He, Baiyan

    2013-12-01

    A method to improve formability of aluminum sheet alloys by a two-stage stamping process with intermediate annealing was developed for a non-age hardenable Al-Mg alloy where the annealing heat treatment provided recovery of cold work from the initial stamping and recrystallization of the microstructure to enhance the forming limits of the material. This method was extended to an age hardenable, Al-Mg-Si alloy, which is complicated by the competing metallurgical effects during heat treatment including recovery (softening effect) vs. precipitation (hardening effect). An annealing heat treatment process condition was discovered wherein the stored strain energy from an initial plastic deformation can be sufficiently recovered to enhance formability in a second deformation; however, there is a deleterious effect on subsequent precipitation hardening. The improvement in formability was quantified with uniaxial tensile tests as well as with the forming limit diagram. Since strain-based forming limit curves (FLC) are sensitive to pre-strain history, both stress-based FLCs and polar-effective-plastic-strain (PEPS) FLCs, which are path-independent, were used to evaluate the forming limits after preform annealing. A technique was developed to calculate the stress-based FLC in which a residual-effective-plastic-strain (REPS) was determined by overlapping the hardening curve of the pre-strained and annealed material with that of the simply-annealed- material. After converting the strain-based FLCs using the constant REPS method, it was found that the stress-based FLCs and the PEPS FLCs of the post-annealed materials were quite similar and both tools are applicable for evaluating the forming limits of Al-Mg-Si alloys for a two-step stamping process with intermediate annealing.

  14. Effect of annealing temperature on the pitting corrosion resistance of super duplex stainless steel UNS S32750

    SciTech Connect

    Tan Hua; Jiang Yiming; Deng Bo; Sun Tao; Xu Juliang; Li Jin

    2009-09-15

    The pitting corrosion resistance of commercial super duplex stainless steels SAF2507 (UNS S32750) annealed at seven different temperatures ranging from 1030 deg. C to 1200 deg. C for 2 h has been investigated by means of potentiostatic critical pitting temperature. The microstructural evolution and pit morphologies of the specimens were studied through optical/scanning electron microscope. Increasing annealing temperature from 1030 deg. C to 1080 deg. C elevates the critical pitting temperature, whereas continuing to increase the annealing temperature to 1200 deg. C decreases the critical pitting temperature. The specimens annealed at 1080 deg. C for 2 h exhibit the best pitting corrosion resistance with the highest critical pitting temperature. The pit morphologies show that the pit initiation sites transfer from austenite phase to ferrite phase as the annealing temperature increases. The aforementioned results can be explained by the variation of pitting resistance equivalent number of ferrite and austenite phase as the annealing temperature changes.

  15. Effect of annealing on the properties of zinc oxide nanofiber thin films grown by spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Sadananda Kumar, N.; Bangera, Kasturi V.; Shivakumar, G. K.

    2013-01-01

    Zinc oxide nanofiber thin films have been deposited on glass substrate by spray pyrolysis technique. The X-ray diffraction studies revealed that the films are polycrystalline with the hexagonal structure and a preferred orientation along (002) direction for films annealed for 1 h at 450 °C. Further increase in annealing time changes the preferred orientation to (100) direction. The scanning electron microscopic analysis showed the formation of ZnO nanofiber with an average diameter of approximately 800 nm for annealed films. The compositional analysis of nanofiber ZnO thin films were studied by time of flight secondary ion mass spectroscopy, which indicated oxygen deficiency in the films. The optical properties of annealed films have shown a variation in the band gap between 3.29 and 3.20 eV. The electrical conductivity of the as grown and annealed films showed an increase in the conductivity by two orders of magnitude with increase in annealing duration.

  16. Synthesis of boron nitride nanotubes by boron ink annealing.

    PubMed

    Li, Lu Hua; Chen, Ying; Glushenkov, Alexey M

    2010-03-12

    Ball-milling and annealing is one effective method for the mass production of boron nitride nanotubes (BNNTs). We report that the method has been modified to a boron (B) ink annealing method. In this new process, the nanosize ball-milled B particles are mixed with metal nitrate in ethanol to form an ink-like solution, and then the ink is annealed in nitrogen-containing gas to form nanotubes. The new method greatly enhances the yield of BNNTs, giving a higher density of nanotubes. These improvements are caused by the addition of metal nitrate and ethanol, both of which can strongly boost the nitriding reaction, as revealed by thermogravimetric analysis. The size and structure of BNNTs can be controlled by varying the annealing conditions. This high-yield production of BNNTs in large quantities enables the large-scale application of BNNTs. PMID:20154372

  17. Mechanism for accurate, protein-assisted DNA annealing by Deinococcus radiodurans DdrB.

    PubMed

    Sugiman-Marangos, Seiji N; Weiss, Yoni M; Junop, Murray S

    2016-04-19

    Accurate pairing of DNA strands is essential for repair of DNA double-strand breaks (DSBs). How cells achieve accurate annealing when large regions of single-strand DNA are unpaired has remained unclear despite many efforts focused on understanding proteins, which mediate this process. Here we report the crystal structure of a single-strand annealing protein [DdrB (DNA damage response B)] in complex with a partially annealed DNA intermediate to 2.2 Å. This structure and supporting biochemical data reveal a mechanism for accurate annealing involving DdrB-mediated proofreading of strand complementarity. DdrB promotes high-fidelity annealing by constraining specific bases from unauthorized association and only releases annealed duplex when bound strands are fully complementary. To our knowledge, this mechanism provides the first understanding for how cells achieve accurate, protein-assisted strand annealing under biological conditions that would otherwise favor misannealing. PMID:27044084

  18. Generation and self-organization of bimetallic Pd/Au nanoparticles on SiO2 by sequential sputtering depositions and annealing processes.

    PubMed

    Ruffino, F; Pecora, E F; Grimaldi, M G

    2012-11-01

    PdAu nanoparticles have been grown on SiO2 by room-temperature sequential sputtering depositions. The nucleation and growth kinetics have been determined crossing atomic force and scanning electron microscopy measurements. From these measurements the mechanisms of the nucleation and growth have been determined. In particular: (1) during the deposition of the first metal (Pd), atoms adsorbed on the substrate are readily trapped on the substrate defects, forming stable nuclei which grow further. During the deposition of the second metal (Au), adsorbed atoms are captured by the clusters formed during the first deposition, before they have time to form a stable nucleus of pure second metal on the surface sites. So, the nucleation is mainly controlled by the Pd and the Au atoms are incorporated essentially by direct impingement of the vapour atoms on the already formed particles. (2) fixing the amount of Pd and Au, during post-deposition thermal treatments, a surface diffusion limited ripening of the NPs occurs. Applying the standard ripening growth theory several parameters characterizing the process were determined, in particular, the growth exponent n and the activation energy E(a). n was found to be dependent on temperature and amount of Au deposited. E(a) was found to linearly increase with the amount of Au deposited. Such a dependence is discussed separating E(a) in two terms: one describing the activation energy for atomic surface diffusion (independent on the amount of Au deposited), the other one describing the activation energy for the film clustering process (dependent on the amount of Au deposited). PMID:23421241

  19. STM study on the surface defects of SnSe induced by thermal annealing

    NASA Astrophysics Data System (ADS)

    Thi Ly, Trinh; Kim, Sang-Ui; Kim, Tae Hoon; Duong, Anh Tuan; Cho, Sunglae; Rhim, S. H.; Kim, Jungdae

    SnSe is a IV - VI semiconductor with 0.86 eV gap, and a single crystal SnSe usually exhibits a p-type characteristic. SnSe is one of 2D layered materials, and it has attracted researchers' attentions due to excellent physical properties for future applications. In particular, exceptionally high ZT value (ZT = ~2.6 at 923 K) was reported for SnSe single crystal (Zhao et al., Nature 508 373 (2014). Even though many researches on SnSe have proposed the possibilities of various applications so far, surprisingly little information is available regarding the microscopic structure of SnSe surfaces. We conducted a systematic study on the surface defect of SnSe induced by thermal annealing via a home-built low temperature scanning tunneling microscopy (STM). Various defects were characterized by STM/STS, and we found that Sn vacancy is a dominating intrinsic defect. The size of vacancy was changed after annealing process in UHV at different temperatures. This work was supported by the National Research Foundation of Korea(NRF) [Nos. NRF-2013R1A1A1008724, NRF-2009-0093818, and NRF-2014R1A4A1071686].

  20. Quantum annealing speedup over simulated annealing on random Ising chains

    NASA Astrophysics Data System (ADS)

    Zanca, Tommaso; Santoro, Giuseppe E.

    2016-06-01

    We show clear evidence of a quadratic speedup of a quantum annealing (QA) Schrödinger dynamics over a Glauber master equation simulated annealing (SA) for a random Ising model in one dimension, via an equal-footing exact deterministic dynamics of the Jordan-Wigner fermionized problems. This is remarkable, in view of the arguments of H. G. Katzgraber et al. [Phys. Rev. X 4, 021008 (2014), 10.1103/PhysRevX.4.021008], since SA does not encounter any phase transition, while QA does. We also find a second remarkable result: that a "quantum-inspired" imaginary-time Schrödinger QA provides a further exponential speedup, i.e., an asymptotic residual error decreasing as a power law τ-μ of the annealing time τ .

  1. [Microscopic colitis: update 2014].

    PubMed

    Burgmann, Konstantin; Fraga, Montserrat; Schoepfer, Alain M; Yun, Pu

    2014-09-01

    Microscopic colitis, which includes lymphocytic colitis and collagenous colitis, represents a frequent cause of chronic watery diarrhea especially in the elderly population. Several medications, such as nonsteroidal antiinflammatory drugs, proton pump inhibitors or antidepressants, as well as cigarette smoking have been recognized as risk factors for microscopic colitis. The diagnosis of microscopic colitis is based on a macroscopically normal ileo-colonoscopy and several biopsies from the entire colon, which demonstrate the pathognomonic histopathologic findings. Therapy is mainly based on the use of budesonide. Other medications, such as mesalazine, cholestyramine and bismuth, have been evaluated as well but the evidence is less solid. PMID:25276996

  2. Mars Life? - Microscopic Structures

    NASA Technical Reports Server (NTRS)

    1996-01-01

    In the center of this electron microscope image of a small chip from a meteorite are several tiny structures that are possible microscopic fossils of primitive, bacteria-like organisms that may have lived on Mars more than 3.6 billion years ago. A two-year investigation by a NASA research team found organic molecules, mineral features characteristic of biological activity and possible microscopic fossils such as these inside of an ancient Martian rock that fell to Earth as a meteorite. The largest possible fossils are less than 1/100th the diameter of a human hair in size while most are ten times smaller.

  3. A Live Specimen Cell for the Microscope.

    ERIC Educational Resources Information Center

    McNeil, D. W.

    1991-01-01

    Provides background and instructions for the assembly of a microaquarium, or specimen cell, in which the dynamic world of living microorganisms can be viewed through a microscope overextended periods of time utilizing the simplest of materials in the process. (JJK)

  4. Formation of silicides in annealed periodic multilayers

    NASA Astrophysics Data System (ADS)

    Maury, H.; Jonnard, P.; Le Guen, K.; André, J.-M.

    2009-05-01

    Periodic multilayers of nanometric period are widely used as optical components for the X-ray and extreme UV (EUV) ranges, in X-ray space telescopes, X-ray microscopes, EUV photolithography or synchrotron beamlines for example. Their optical performances depend on the quality of the interfaces between the various layers: chemical interdiffusion or mechanical roughness shifts the application wavelength and can drastically decrease the reflectance. Since under high thermal charge interdiffusion is known to get enhanced, the study of the thermal stability of such structures is essential to understand how interfacial compounds develop. We have characterized X-ray and EUV siliconcontaining multilayers (Mo/Si, Sc/Si and Mg/SiC) as a function of the annealing temperature (up to 600°C) using two non-destructive methods. X-ray emission from the silicon atoms, describing the Si valence states, is used to determine the chemical nature of the compounds present in the interphases while X-ray reflectivity in the hard and soft X-ray ranges can be related to the optical properties. In the three cases, interfacial metallic (Mo, Sc, Mg) silicides are evidenced and the thickness of the interphase increases with the annealing temperature. For Mo/Si and Sc/Si multilayers, silicides are even present in the as-prepared multilayers. Characteristic parameters of the stacks are determined: composition of the interphases, thickness and roughness of the layers and interphases if any. Finally, we have evidenced the maximum temperature of application of these multilayers to minimize interdiffusion.

  5. Structural, morphological and optical properties of Ag-AgO thin films with the effect of increasing film thickness and annealing temperature

    NASA Astrophysics Data System (ADS)

    Pal, Anil Kumar; Bharathi Mohan, D.

    2015-10-01

    Ag films of thickness ranging from 5 to 60 nm were deposited by thermal evaporation technique followed by air annealing process with temperature varying from 50 to 250 °C. Morphological properties such as particle size, shape, surface roughness and number particles density were studied by atomic force microscope (AFM). The structural transition from quasi-amorphous to nanocrystalline to crystalline upon increasing film thickness and annealing temperature were studied. Ag films with smallest particle size and surface roughness were achieved up to film thickness of 7 nm. The possibility of surface oxidation of Ag on both as deposited and annealed films was studied through Raman mapping by using confocal Raman spectroscopy. Ag film was X-ray amorphous even after annealing process up to the film thickness of 7 nm and above which the crystallinity reached maximum at 250 °C. The surface plasmon resonance (SPR) with a symmetric line shape due to dipole-dipole interactions was found to be very strong for film thickness of 5 nm at 100 °C, attributed to the formation of smaller Ag NPs size of ∼22 nm with least size distribution and higher particles number density of ∼1625 μm-2 in a self-organized fashion. With an increase of film thickness and annealing temperature, an asymmetric broad absorption arose due to increase in damping of collective electron oscillation on bulky NPs. Theoretical absorption spectra were simulated using extended Maxwell garnet method showing a decent agreement with experimental data. The real and imaginary parts of dielectric constants were determined and plotted for different film thicknesses of as deposited Ag films. Even though the film is oxidized at the surface level, it still can be used for plasmonic sensor applications however the film thickness should be approximately 7 nm for the enhanced result.

  6. Reduction of Annealing Times for Energy Conservation in Aluminum

    SciTech Connect

    Anthony D. Rollett; Hasso Weiland; Mohammed Alvi; Abhijit Brahme

    2005-08-31

    Carnegie Mellon University was teamed with the Alcoa Technical Center with support from the US Dept. of Energy (Office of Industrial Technology) and the Pennsylvania Technology Investment Authority (PTIA) to make processing of aluminum less costly and more energy efficient. Researchers in the Department of Materials Science and Engineering have investigated how annealing processes in the early stages of aluminum processing affect the structure and properties of the material. Annealing at high temperatures consumes significant amounts of time and energy. By making detailed measurements of the crystallography and morphology of internal structural changes they have generated new information that will provide a scientific basis for shortening processing times and consuming less energy during annealing.

  7. Hyperspectral confocal microscope

    NASA Astrophysics Data System (ADS)

    Sinclair, Michael B.; Haaland, David M.; Timlin, Jerilyn A.; Jones, Howland D. T.

    2006-08-01

    We have developed a new, high performance, hyperspectral microscope for biological and other applications. For each voxel within a three-dimensional specimen, the microscope simultaneously records the emission spectrum from 500 nm to 800 nm, with better than 3 nm spectral resolution. The microscope features a fully confocal design to ensure high spatial resolution and high quality optical sectioning. Optical throughput and detection efficiency are maximized through the use of a custom prism spectrometer and a backside thinned electron multiplying charge coupled device (EMCCD) array. A custom readout mode and synchronization scheme enable 512-point spectra to be recorded at a rate of 8300 spectra per second. In addition, the EMCCD readout mode eliminates curvature and keystone artifacts that often plague spectral imaging systems. The architecture of the new microscope is described in detail, and hyperspectral images from several specimens are presented.

  8. Hyperspectral confocal microscope.

    PubMed

    Sinclair, Michael B; Haaland, David M; Timlin, Jerilyn A; Jones, Howland D T

    2006-08-20

    We have developed a new, high performance, hyperspectral microscope for biological and other applications. For each voxel within a three-dimensional specimen, the microscope simultaneously records the emission spectrum from 500 nm to 800 nm, with better than 3 nm spectral resolution. The microscope features a fully confocal design to ensure high spatial resolution and high quality optical sectioning. Optical throughput and detection efficiency are maximized through the use of a custom prism spectrometer and a backside thinned electron multiplying charge coupled device (EMCCD) array. A custom readout mode and synchronization scheme enable 512-point spectra to be recorded at a rate of 8300 spectra per second. In addition, the EMCCD readout mode eliminates curvature and keystone artifacts that often plague spectral imaging systems. The architecture of the new microscope is described in detail, and hyperspectral images from several specimens are presented. PMID:16892134

  9. Assessment of Petrological Microscopes.

    ERIC Educational Resources Information Center

    Mathison, Charter Innes

    1990-01-01

    Presented is a set of procedures designed to check the design, ergonomics, illumination, function, optics, accessory equipment, and image quality of a microscope being considered for purchase. Functions for use in a petrology or mineralogy laboratory are stressed. (CW)

  10. Microscope collision protection apparatus

    DOEpatents

    DeNure, Charles R.

    2001-10-23

    A microscope collision protection apparatus for a remote control microscope which protects the optical and associated components from damage in the event of an uncontrolled collision with a specimen, regardless of the specimen size or shape. In a preferred embodiment, the apparatus includes a counterbalanced slide for mounting the microscope's optical components. This slide replaces the rigid mounts on conventional upright microscopes with a precision ball bearing slide. As the specimen contacts an optical component, the contacting force will move the slide and the optical components mounted thereon. This movement will protect the optical and associated components from damage as the movement causes a limit switch to be actuated, thereby stopping all motors responsible for the collision.

  11. Searches for signals from microscopic black holes in processes of proton collisions at {radical} s = 7 TeV in the CMS experiment at the LHC

    SciTech Connect

    Savina, M. V.

    2013-09-15

    If the fundamental scale of multidimensional gravity is about one or several TeV units, microscopic black holes or objects referred to as string balls may be produced at the LHC. The most recent results obtained by the CMS Collaboration at the LHC from searches for such signals at the c.m. protoninteraction energy of 7 TeV and for an integrated luminosity of 4.7 fb{sup -1}. Lower limits on the masses of objects of strongly acting gravity were set in the parameter region accessible to tests at the present time. Prospects for further research in this field are discussed.

  12. Infrared microscope inspection apparatus

    DOEpatents

    Forman, Steven E.; Caunt, James W.

    1985-02-26

    Apparatus and system for inspecting infrared transparents, such as an array of photovoltaic modules containing silicon solar cells, includes an infrared microscope, at least three sources of infrared light placed around and having their axes intersect the center of the object field and means for sending the reflected light through the microscope. The apparatus is adapted to be mounted on an X-Y translator positioned adjacent the object surface.

  13. Infrared microscope inspection apparatus

    DOEpatents

    Forman, S.E.; Caunt, J.W.

    1985-02-26

    Apparatus and system for inspecting infrared transparents, such as an array of photovoltaic modules containing silicon solar cells, includes an infrared microscope, at least three sources of infrared light placed around and having their axes intersect the center of the object field and means for sending the reflected light through the microscope. The apparatus is adapted to be mounted on an X-Y translator positioned adjacent the object surface. 4 figs.

  14. 3D microscope

    NASA Astrophysics Data System (ADS)

    Iizuka, Keigo

    2008-02-01

    In order to circumvent the fact that only one observer can view the image from a stereoscopic microscope, an attachment was devised for displaying the 3D microscopic image on a large LCD monitor for viewing by multiple observers in real time. The principle of operation, design, fabrication, and performance are presented, along with tolerance measurements relating to the properties of the cellophane half-wave plate used in the design.

  15. Hypoxia in Microscopic Tumors

    PubMed Central

    Li, Xiao-Feng; O’Donoghue, Joseph A

    2008-01-01

    Tumor hypoxia has been commonly observed in a broad spectrum of primary solid malignancies. Hypoxia is associated with tumor progression, increased aggressiveness, enhanced metastatic potential and poor prognosis. Hypoxic tumor cells are resistant to radiotherapy and some forms of chemotherapy. Using an animal model, we recently showed that microscopic tumors less than 1 mm diameter were severely hypoxic. In this review, models and techniques for the study of hypoxia in microscopic tumors are discussed. PMID:18384940

  16. Experimental quantum annealing: case study involving the graph isomorphism problem

    PubMed Central

    Zick, Kenneth M.; Shehab, Omar; French, Matthew

    2015-01-01

    Quantum annealing is a proposed combinatorial optimization technique meant to exploit quantum mechanical effects such as tunneling and entanglement. Real-world quantum annealing-based solvers require a combination of annealing and classical pre- and post-processing; at this early stage, little is known about how to partition and optimize the processing. This article presents an experimental case study of quantum annealing and some of the factors involved in real-world solvers, using a 504-qubit D-Wave Two machine and the graph isomorphism problem. To illustrate the role of classical pre-processing, a compact Hamiltonian is presented that enables a reduced Ising model for each problem instance. On random N-vertex graphs, the median number of variables is reduced from N2 to fewer than N log2 N and solvable graph sizes increase from N = 5 to N = 13. Additionally, error correction via classical post-processing majority voting is evaluated. While the solution times are not competitive with classical approaches to graph isomorphism, the enhanced solver ultimately classified correctly every problem that was mapped to the processor and demonstrated clear advantages over the baseline approach. The results shed some light on the nature of real-world quantum annealing and the associated hybrid classical-quantum solvers. PMID:26053973

  17. Experimental quantum annealing: case study involving the graph isomorphism problem

    NASA Astrophysics Data System (ADS)

    Zick, Kenneth M.; Shehab, Omar; French, Matthew

    2015-06-01

    Quantum annealing is a proposed combinatorial optimization technique meant to exploit quantum mechanical effects such as tunneling and entanglement. Real-world quantum annealing-based solvers require a combination of annealing and classical pre- and post-processing; at this early stage, little is known about how to partition and optimize the processing. This article presents an experimental case study of quantum annealing and some of the factors involved in real-world solvers, using a 504-qubit D-Wave Two machine and the graph isomorphism problem. To illustrate the role of classical pre-processing, a compact Hamiltonian is presented that enables a reduced Ising model for each problem instance. On random N-vertex graphs, the median number of variables is reduced from N2 to fewer than N log2 N and solvable graph sizes increase from N = 5 to N = 13. Additionally, error correction via classical post-processing majority voting is evaluated. While the solution times are not competitive with classical approaches to graph isomorphism, the enhanced solver ultimately classified correctly every problem that was mapped to the processor and demonstrated clear advantages over the baseline approach. The results shed some light on the nature of real-world quantum annealing and the associated hybrid classical-quantum solvers.

  18. Quantum versus simulated annealing in wireless interference network optimization

    PubMed Central

    Wang, Chi; Chen, Huo; Jonckheere, Edmond

    2016-01-01

    Quantum annealing (QA) serves as a specialized optimizer that is able to solve many NP-hard problems and that is believed to have a theoretical advantage over simulated annealing (SA) via quantum tunneling. With the introduction of the D-Wave programmable quantum annealer, a considerable amount of effort has been devoted to detect and quantify quantum speedup. While the debate over speedup remains inconclusive as of now, instead of attempting to show general quantum advantage, here, we focus on a novel real-world application of D-Wave in wireless networking—more specifically, the scheduling of the activation of the air-links for maximum throughput subject to interference avoidance near network nodes. In addition, D-Wave implementation is made error insensitive by a novel Hamiltonian extra penalty weight adjustment that enlarges the gap and substantially reduces the occurrence of interference violations resulting from inevitable spin bias and coupling errors. The major result of this paper is that quantum annealing benefits more than simulated annealing from this gap expansion process, both in terms of ST99 speedup and network queue occupancy. It is the hope that this could become a real-word application niche where potential benefits of quantum annealing could be objectively assessed. PMID:27181056

  19. Quantum versus simulated annealing in wireless interference network optimization

    NASA Astrophysics Data System (ADS)

    Wang, Chi; Chen, Huo; Jonckheere, Edmond

    2016-05-01

    Quantum annealing (QA) serves as a specialized optimizer that is able to solve many NP-hard problems and that is believed to have a theoretical advantage over simulated annealing (SA) via quantum tunneling. With the introduction of the D-Wave programmable quantum annealer, a considerable amount of effort has been devoted to detect and quantify quantum speedup. While the debate over speedup remains inconclusive as of now, instead of attempting to show general quantum advantage, here, we focus on a novel real-world application of D-Wave in wireless networking—more specifically, the scheduling of the activation of the air-links for maximum throughput subject to interference avoidance near network nodes. In addition, D-Wave implementation is made error insensitive by a novel Hamiltonian extra penalty weight adjustment that enlarges the gap and substantially reduces the occurrence of interference violations resulting from inevitable spin bias and coupling errors. The major result of this paper is that quantum annealing benefits more than simulated annealing from this gap expansion process, both in terms of ST99 speedup and network queue occupancy. It is the hope that this could become a real-word application niche where potential benefits of quantum annealing could be objectively assessed.

  20. Quantum versus simulated annealing in wireless interference network optimization.

    PubMed

    Wang, Chi; Chen, Huo; Jonckheere, Edmond

    2016-01-01

    Quantum annealing (QA) serves as a specialized optimizer that is able to solve many NP-hard problems and that is believed to have a theoretical advantage over simulated annealing (SA) via quantum tunneling. With the introduction of the D-Wave programmable quantum annealer, a considerable amount of effort has been devoted to detect and quantify quantum speedup. While the debate over speedup remains inconclusive as of now, instead of attempting to show general quantum advantage, here, we focus on a novel real-world application of D-Wave in wireless networking-more specifically, the scheduling of the activation of the air-links for maximum throughput subject to interference avoidance near network nodes. In addition, D-Wave implementation is made error insensitive by a novel Hamiltonian extra penalty weight adjustment that enlarges the gap and substantially reduces the occurrence of interference violations resulting from inevitable spin bias and coupling errors. The major result of this paper is that quantum annealing benefits more than simulated annealing from this gap expansion process, both in terms of ST99 speedup and network queue occupancy. It is the hope that this could become a real-word application niche where potential benefits of quantum annealing could be objectively assessed. PMID:27181056

  1. Dark-field imaging based on post-processed electron backscatter diffraction patterns of bulk crystalline materials in a scanning electron microscope.

    PubMed

    Brodusch, Nicolas; Demers, Hendrix; Gauvin, Raynald

    2015-01-01

    Dark-field (DF) images were acquired in the scanning electron microscope with an offline procedure based on electron backscatter diffraction (EBSD) patterns (EBSPs). These EBSD-DF images were generated by selecting a particular reflection on the electron backscatter diffraction pattern and by reporting the intensity of one or several pixels around this point at each pixel of the EBSD-DF image. Unlike previous studies, the diffraction information of the sample is the basis of the final image contrast with a pixel scale resolution at the EBSP providing DF imaging in the scanning electron microscope. The offline facility of this technique permits the selection of any diffraction condition available in the diffraction pattern and displaying the corresponding image. The high number of diffraction-based images available allows a better monitoring of deformation structures compared to electron channeling contrast imaging (ECCI) which is generally limited to a few images of the same area. This technique was applied to steel and iron specimens and showed its high capability in describing more rigorously the deformation structures around micro-hardness indents. Due to the offline relation between the reference EBSP and the EBSD-DF images, this new technique will undoubtedly greatly improve our knowledge of deformation mechanism and help to improve our understanding of the ECCI contrast mechanisms. PMID:25461589

  2. Effect of annealing in hydrogen atmosphere on ZnO films for field emission display

    NASA Astrophysics Data System (ADS)

    Zulkifli, Zurita; Sharma, Subash; Shinde, Sachin; Kalita, Golap; Tanemura, M.

    2015-11-01

    Surface morphology, crystallinity, conductivity and optical transmittance of ZnO films can be modified by annealing process. Hydrogen is one of the popular annealing gases as well as nitrogen, argon, oxygen and air which are commonly used for thin film cleaning or the removal of native oxide. In general, annealing is done at high temperatures (> 600degC) to improve the film properties. From a view point of environment, however, lower annealing temperature is preferable. In this work, low annealing process was challenged to understand the effect of annealing temperature on properties of ZnO thin films and nanostructured film grown on glass substrates for transparent field emission device applications. The annealing temperature employed was 100, 200 and 450°C at 100 sccm hydrogen flow rate. ZnO thin films were deposited by RF magnetron sputtering. The ZnO thin films were characterized by X-ray diffraction analysis (XRD), Atomic Force Microscopy (AFM), UV-VIS and Raman spectroscopy. The sheet resistances reduced about 15 kohm/sq at low annealing temperature. By contrast, the optical transmittance did not show any significant changes after annealing. The FE current density increased after the ZnO nanostructures film was annealed in 100°C. The results obtained could motivate a surface treatment for flexible ZnO thin film since the substrate is always suffered by heat.

  3. Annealing effect on structural and optical properties of chemical bath deposited MnS thin film

    NASA Astrophysics Data System (ADS)

    Ulutas, Cemal; Gumus, Cebrail

    2016-03-01

    MnS thin film was prepared by the chemical bath deposition (CBD) method on commercial microscope glass substrate deposited at 30 °C. The as-deposited film was given thermal annealing treatment in air atmosphere at various temperatures (150, 300 and 450 °C) for 1 h. The MnS thin film was characterized by using X-ray diffraction (XRD), UV-vis spectrophotometer and Hall effect measurement system. The effect of annealing temperature on the structural, electrical and optical properties such as optical constants of refractive index (n) and energy band gap (Eg) of the film was determined. XRD measurements reveal that the film is crystallized in the wurtzite phase and changed to tetragonal Mn3O4 phase after being annealed at 300 °C. The energy band gap of film decreased from 3.69 eV to 3.21 eV based on the annealing temperature.

  4. Effective dopant activation by susceptor-assisted microwave annealing of low energy boron implanted and phosphorus implanted silicon

    SciTech Connect

    Zhao, Zhao; Vemuri, Rajitha N. P.; Alford, T. L.; David Theodore, N.; Lu, Wei; Lau, S. S.; Lanz, A.

    2013-12-28

    Rapid processing and reduced end-of-range diffusion result from susceptor-assisted microwave (MW) annealing, making this technique an efficient processing alternative for electrically activating dopants within ion-implanted semiconductors. Sheet resistance and Hall measurements provide evidence of electrical activation. Susceptor-assisted MW annealing, of ion-implanted Si, enables more effective dopant activation and at lower temperatures than required for rapid thermal annealing (RTA). Raman spectroscopy and ion channeling analyses are used to monitor the extent of ion implantation damage and recrystallization. The presence and behavior of extended defects are monitored by cross-section transmission electron microscopy. Phosphorus implanted Si samples experience effective electrical activation upon MW annealing. On the other hand, when boron implanted Si is MW annealed, the growth of extended defects results in reduced crystalline quality that hinders the electrical activation process. Further comparison of dopant diffusion resulting from MW annealing and rapid thermal annealing is performed using secondary ion mass spectroscopy. MW annealed ion implanted samples show less end-of-range diffusion when compared to RTA samples. In particular, MW annealed P{sup +} implanted samples achieve no visible diffusion and equivalent electrical activation at a lower temperature and with a shorter time-duration of annealing compared to RTA. In this study, the peak temperature attained during annealing does not depend on the dopant species or dose, for susceptor-assisted MW annealing of ion-implanted Si.

  5. Annealing properties of rice starch.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thermal properties of starch can be modified by annealing, i.e., a pre-treatment in excessive amounts of water at temperatures below the gelatinization temperatures. This treatment is known to improve the crystalline properties, and is a useful tool to gain a better control of the functional proper...

  6. Radiation and annealing response of WWER 440 beltline welding seams

    NASA Astrophysics Data System (ADS)

    Viehrig, Hans-Werner; Houska, Mario; Altstadt, Eberhard

    2015-01-01

    The focus of this paper is on the irradiation response and the effect of thermal annealing in weld materials extracted from decommissioned WWER 440 reactor pressure vessels of the nuclear power plant Greifswald. The characterisation is based on the measurement of the hardness, the yield stress, the Master Curve reference temperature, T0, and the Charpy-V transition temperature through the thickness of multi-layer beltline welding seams in the irradiated and the thermally annealed condition. Additionally, the weld bead structure was characterised by light microscopic studies. We observed a large variation in the through thickness T0 values in the irradiated as well as in thermally annealed condition. The T0 values measured with the T-S-oriented Charpy size SE(B) specimens cut from different thickness locations of the multilayer welding seams strongly depend on the intrinsic weld bead structure along the crack tip. The Master Curve, T0, and Charpy-V, TT47J, based ductile-to-brittle transition temperature progressions through the thickness of the multi-layer welding seam do not correspond to the forecast according to the Russian code. In general, the fracture toughness values at cleavage failure, KJc, measured on SE(B) specimens from the irradiated and large-scale thermally annealed beltline welding seams follow the Master Curve description, but more than the expected number lie outside the curves for 2% and 98% fracture probability. In this case the test standard ASTM E1921 indicates the investigated multi-layer weld metal as not uniform. The multi modal Master Curve based approach describes the temperature dependence of the specimen size adjusted KJc-1T values well. Thermal annealing at 475 °C for 152 h results in the expected decrease of the hardness and tensile strength and the shift of Master Curve and Charpy-V based ductile-to-brittle transition temperatures to lower values.

  7. Fabrication of Si surface pattern by Ar beam irradiation and annealing method

    SciTech Connect

    Zhang, J.; Momota, S.; Maeda, K.; Terauchi, H.; Furuta, M.; Kawaharamura, T.; Nitta, N.; Wang, D.

    2012-11-06

    The fabrication process of crater structures on Si crystal has been studied by an irradiation of Ar beam and a thermal annealing at 600 Degree-Sign C. The fabricated surface was measured by field emission scanning electron microscope and atomic force microscope. The results have shown the controllability of specifications of crater formation such as density, diameter and depth by changing two irradiation parameters, fluence and energy of Ar ions. By changing the fluence over a range of 1 {approx} 10 Multiplication-Sign 10{sup 16}/cm{sup 2}, we could control a density of crater 0 {approx} 39 counts/100{mu}m{sup 2}. By changing the energy over a range of 90 {approx} 270 keV, we could control a diameter and a depth of crater in 0.8 {approx} 4.1{mu}m and 99 {approx} 229nm, respectively. The present result is consistent with the previously proposed model that the crater structure would be arising from an exfoliated surface layer of silicon. The present result has indicated the possibility of the crater production phenomena as a hopeful method to fabricate the surface pattern on a micro-nano meter scale.

  8. Preparation and Loading Process of Single Crystalline Samples into a Gas Environmental Cell Holder for In Situ Atomic Resolution Scanning Transmission Electron Microscopic Observation.

    PubMed

    Straubinger, Rainer; Beyer, Andreas; Volz, Kerstin

    2016-06-01

    A reproducible way to transfer a single crystalline sample into a gas environmental cell holder for in situ transmission electron microscopic (TEM) analysis is shown in this study. As in situ holders have only single-tilt capability, it is necessary to prepare the sample precisely along a specific zone axis. This can be achieved by a very accurate focused ion beam lift-out preparation. We show a step-by-step procedure to prepare the sample and transfer it into the gas environmental cell. The sample material is a GaP/Ga(NAsP)/GaP multi-quantum well structure on Si. Scanning TEM observations prove that it is possible to achieve atomic resolution at very high temperatures in a nitrogen environment of 100,000 Pa. PMID:27026281

  9. Restoring defect structures in 3C-SiC/Si (001) from spherical aberration-corrected high-resolution transmission electron microscope images by means of deconvolution processing.

    PubMed

    Wen, C; Wan, W; Li, F H; Tang, D

    2015-04-01

    The [110] cross-sectional samples of 3C-SiC/Si (001) were observed with a spherical aberration-corrected 300 kV high-resolution transmission electron microscope. Two images taken not close to the Scherzer focus condition and not representing the projected structures intuitively were utilized for performing the deconvolution. The principle and procedure of image deconvolution and atomic sort recognition are summarized. The defect structure restoration together with the recognition of Si and C atoms from the experimental images has been illustrated. The structure maps of an intrinsic stacking fault in the area of SiC, and of Lomer and 60° shuffle dislocations at the interface have been obtained at atomic level. PMID:25637810

  10. Utilization of computer processed high definition video imaging for measuring motility of microscopic nematode stages on a quantitative scale: “The Worminator”

    PubMed Central

    Storey, Bob; Marcellino, Chris; Miller, Melissa; Maclean, Mary; Mostafa, Eman; Howell, Sue; Sakanari, Judy; Wolstenholme, Adrian; Kaplan, Ray

    2014-01-01

    A major hindrance to evaluating nematode populations for anthelmintic resistance, as well as for screening existing drugs, new compounds, or bioactive plant extracts for anthelmintic properties, is the lack of an efficient, objective, and reproducible in vitro assay that is adaptable to multiple life stages and parasite genera. To address this need we have developed the “Worminator” system, which objectively and quantitatively measures the motility of microscopic stages of parasitic nematodes. The system is built around the computer application “WormAssay”, developed at the Center for Discovery and Innovation in Parasitic Diseases at the University of California, San Francisco. WormAssay was designed to assess motility of macroscopic parasites for the purpose of high throughput screening of potential anthelmintic compounds, utilizing high definition video as an input to assess motion of adult stage (macroscopic) parasites (e.g. Brugia malayi). We adapted this assay for use with microscopic parasites by modifying the software to support a full frame analysis mode that applies the motion algorithm to the entire video frame. Thus, the motility of all parasites in a given well are recorded and measured simultaneously. Assays performed on third-stage larvae (L3) of the bovine intestinal nematode Cooperia spp., as well as microfilariae (mf) of the filarioid nematodes B. malayi and Dirofilaria immitis, yielded reproducible dose responses using the macrocyclic lactones ivermectin, doramectin, and moxidectin, as well as the nicotinic agonists, pyrantel, oxantel, morantel, and tribendimidine. This new computer based-assay is simple to use, requires minimal new investment in equipment, is robust across nematode genera and developmental stage, and does not require subjective scoring of motility by an observer. Thus, the “Worminator” provides a relatively low-cost platform for developing genera- and stage-specific assays with high efficiency and reproducibility, low

  11. Annealing texture of nanostructured IF steel

    SciTech Connect

    Jamaati, Roohollah

    2015-08-15

    In the present work, the evolution of annealing texture in nanostructured interstitial free steel fabricated via accumulative roll bonding (ARB) process was investigated. Textural evolution after post-annealing of ARB-processed samples was evaluated using X-ray diffraction. There were several texture transitions in the γ-fiber and ζ-fiber during ARB and post-annealing treatment. It was found that with increasing the number of ARB cycles, the volume fraction of the low angle grain boundary decreased and the high angle grain boundary fraction increased. Also, the shear texture was dominant after the first cycle, while for other samples, the rolling texture was dominant. The one-cycle sample clearly indicated a weak α-fiber and γ-fiber and a relatively strong ζ-fiber. In addition, during the recrystallization and before the grain growth, the intensity of α-fiber and γ-fiber decreased, the intensity of ζ-fiber increased, and the intensity of (011)〈100〉 orientation in the ε-fiber and η-fiber increased. Moreover, it was concluded that the transition from the rolling texture to the shear one was a sign of occurrence of the recrystallization (before the grain growth). Finally, with increasing the number of ARB cycles, the intensity of rolling and shear textures saturated and a stable texture formed. - Highlights: • There were texture transitions in the γ-fiber and ζ-fiber. • When the number of cycles increased, the low angle grain boundaries decreased. • The shear texture was dominant after the first cycle. • Transition from rolling texture to shear one was a sign of recrystallization. • With increasing the number of ARB cycles, a stable texture formed.

  12. Integrated elastic microscope device

    NASA Astrophysics Data System (ADS)

    Lee, W. M.; Wright, D.; Watkins, R.; Cen, Zi

    2015-03-01

    The growing power of imaging and computing power of smartphones is creating the possibility of converting your smartphone into a high power pocket microscopy system. High quality miniature microscopy lenses attached to smartphone are typically made with glass or plastics that can only be produce at low cost with high volume. To revise the paradigm of microscope lenses, we devised a simple droplet lens fabrication technique that which produces low cost and high performance lens. Each lens is integrated into thin 3-D printed holder with complimentary light emitted diode (LEDs) that clips onto majority of smartphones. The integrated device converts a smartphone into a high power optical microscope/dermatoscope at around $2. This low cost device has wide application in a multitude of practical uses such as material inspection, dermascope and educational microscope.

  13. Rapid thermal annealing effect on the spatial resistivity distribution of AZO thin films deposited by pulsed-direct-current sputtering for solar cells applications

    NASA Astrophysics Data System (ADS)

    Ayachi, Boubakeur; Aviles, Thomas; Vilcot, Jean-Pierre; Sion, Cathy

    2016-03-01

    Room temperature deposited aluminium-doped zinc oxide thin films on glass substrate, using pulsed-DC magnetron sputtering, have shown high optical transmittance and low electrical resistivity with high uniformity of its spatial distribution after they were exposed to a rapid thermal annealing process at 400 °C under N2H2 atmosphere. It is particularly interesting to note that such an annealing process of AZO thin films for only 30 s was sufficient, on one hand to improve their optical transmittance from 73% to 86%, on the other hand to both decrease their resistivity from 1.7 × 10-3 Ω cm to 5.1 × 10-4 Ω cm and achieve the highest uniformity spatial distribution. To understand the mechanisms behind such improvements of the optoelectronic properties, electrical, optical, structural and morphological changes as a function of annealing time have been investigated by using hall measurement, UV-visible spectrometry, X-ray diffraction and scanning electron microscope imaging, respectively.

  14. Electron microscope studies

    SciTech Connect

    Crewe, A.V.; Kapp, O.H.

    1992-07-01

    This is a report covering the research performed in the Crewe laboratory between 1964 and 1992. Because of limitations of space we have provided relatively brief summaries of the major research directions of the facility during these years. A complete bibliography has been included and we have referenced groups of pertinent publications at the beginning of each section. This report summarizes our efforts to develop better electron microscopes and chronicles many of the experimental programs, in materials science and biology, that acted both as a stimulus to better microscope design and also as a testing ground for many instrumental innovations.

  15. Compact Microscope Imaging System Developed

    NASA Technical Reports Server (NTRS)

    McDowell, Mark

    2001-01-01

    The Compact Microscope Imaging System (CMIS) is a diagnostic tool with intelligent controls for use in space, industrial, medical, and security applications. The CMIS can be used in situ with a minimum amount of user intervention. This system, which was developed at the NASA Glenn Research Center, can scan, find areas of interest, focus, and acquire images automatically. Large numbers of multiple cell experiments require microscopy for in situ observations; this is only feasible with compact microscope systems. CMIS is a miniature machine vision system that combines intelligent image processing with remote control capabilities. The software also has a user-friendly interface that can be used independently of the hardware for post-experiment analysis. CMIS has potential commercial uses in the automated online inspection of precision parts, medical imaging, security industry (examination of currency in automated teller machines and fingerprint identification in secure entry locks), environmental industry (automated examination of soil/water samples), biomedical field (automated blood/cell analysis), and microscopy community. CMIS will improve research in several ways: It will expand the capabilities of MSD experiments utilizing microscope technology. It may be used in lunar and Martian experiments (Rover Robot). Because of its reduced size, it will enable experiments that were not feasible previously. It may be incorporated into existing shuttle orbiter and space station experiments, including glove-box-sized experiments as well as ground-based experiments.

  16. Microscope Image of Scavenged Particles

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This image from NASA's Phoenix Mars Lander's Optical Microscope shows a strongly magnetic surface which has scavenged particles from within the microscope enclosure before a sample delivery from the lander's Robotic Arm. The particles correspond to the larger grains seen in fine orange material that makes up most of the soil at the Phoenix site. They vary in color, but are of similar size, about one-tenth of a millimeter.

    As the microscope's sample wheel moved during operation, these particles also shifted, clearing a thin layer of the finer orange particles that have also been collected. Together with the previous image, this shows that the larger grains are much more magnetic than the fine orange particles with a much larger volume of the grains being collected by the magnet. The image is 2 milimeters across.

    It is speculated that the orange material particles are a weathering product from the larger grains, with the weathering process both causing a color change and a loss of magnetism.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by JPL, Pasadena, Calif. Spacecraft development was by Lockheed Martin Space Systems, Denver.

  17. Influence of laser annealing on SiOx films properties

    NASA Astrophysics Data System (ADS)

    Gavrylyuk, O. O.; Semchuk, O. Yu.; Steblova, O. V.; Evtukh, A. A.; Fedorenko, L. L.; Bratus, O. L.; Zlobin, S. O.; Karlsteen, M.

    2015-05-01

    The interaction of laser irradiation with SiOx films, and the process of decomposition of SiOx on SiO2 and Si nanocrystals under the influence of laser irradiation are investigated. The mathematical modeling of temperature distribution in a c-Si wafer as well as on its surface is carried out. It is shown that laser pulses can efficiently heat up the samples of crystalline silicon. Using multi-pulse procedure, the temperature necessary for annealing can be achieved with lower intensity of laser irradiation. Experimental investigations of laser-annealed SiOx films allowed determining their transformation with the formation of nanoislands. It was concluded that the surface topology, dielectric matrix structure, and electrical conductivity depend on laser beam intensity during the annealing process.

  18. Coordination Hydrothermal Interconnection Java-Bali Using Simulated Annealing

    NASA Astrophysics Data System (ADS)

    Wicaksono, B.; Abdullah, A. G.; Saputra, W. S.

    2016-04-01

    Hydrothermal power plant coordination aims to minimize the total cost of operating system that is represented by fuel costand constraints during optimization. To perform the optimization, there are several methods that can be used. Simulated Annealing (SA) is a method that can be used to solve the optimization problems. This method was inspired by annealing or cooling process in the manufacture of materials composed of crystals. The basic principle of hydrothermal power plant coordination includes the use of hydro power plants to support basic load while thermal power plants were used to support the remaining load. This study used two hydro power plant units and six thermal power plant units with 25 buses by calculating transmission losses and considering power limits in each power plant unit aided by MATLAB software during the process. Hydrothermal power plant coordination using simulated annealing plants showed that a total cost of generation for 24 hours is 13,288,508.01.

  19. Optical Analysis of Microscope Images

    NASA Astrophysics Data System (ADS)

    Biles, Jonathan R.

    Microscope images were analyzed with coherent and incoherent light using analog optical techniques. These techniques were found to be useful for analyzing large numbers of nonsymbolic, statistical microscope images. In the first part phase coherent transparencies having 20-100 human multiple myeloma nuclei were simultaneously photographed at 100 power magnification using high resolution holographic film developed to high contrast. An optical transform was obtained by focussing the laser onto each nuclear image and allowing the diffracted light to propagate onto a one dimensional photosensor array. This method reduced the data to the position of the first two intensity minima and the intensity of successive maxima. These values were utilized to estimate the four most important cancer detection clues of nuclear size, shape, darkness, and chromatin texture. In the second part, the geometric and holographic methods of phase incoherent optical processing were investigated for pattern recognition of real-time, diffuse microscope images. The theory and implementation of these processors was discussed in view of their mutual problems of dimness, image bias, and detector resolution. The dimness problem was solved by either using a holographic correlator or a speckle free laser microscope. The latter was built using a spinning tilted mirror which caused the speckle to change so quickly that it averaged out during the exposure. To solve the bias problem low image bias templates were generated by four techniques: microphotography of samples, creation of typical shapes by computer graphics editor, transmission holography of photoplates of samples, and by spatially coherent color image bias removal. The first of these templates was used to perform correlations with bacteria images. The aperture bias was successfully removed from the correlation with a video frame subtractor. To overcome the limited detector resolution it is necessary to discover some analog nonlinear intensity

  20. Implantation activation annealing of Si-implanted gallium nitride at temperatures > 1,100 C

    SciTech Connect

    Zolper, J.C.; Han, J.; Biefeld, R.M.

    1997-06-01

    The activation annealing of Si-implanted GaN is reported for temperatures from 1,100 to 1,400 C. Although previous work has shown that Si-implanted GaN can be activated by a rapid thermal annealing at {approximately}1,100 C, it was also shown that significant damage remained in the crystal. Therefore, both AlN-encapsulated and uncapped Si-implanted GaN samples were annealed in a metal organic chemical vapor deposition system in a N{sub 2}/NH{sub 3} ambient to further assess the annealing process. Electrical Hall characterization shows increases in carrier density and mobility for annealing up to 1,300 C before degrading at 1,400 C due to decomposition of the GaN epilayer. Rutherford backscattering spectra show that the high annealing temperatures reduce the implantation induced damage profile but do not completely restore the as-grown crystallinity.

  1. The precipitation in annealing and its effect on permittivity of Fe-Si-Al powders

    NASA Astrophysics Data System (ADS)

    Li, Gang; Cui, Yin; Zhang, Nan; Wang, Xin; Xie, Jian Liang

    2016-01-01

    SEM images show that some precipitates distributed on the surface of as-annealed Fe-Si-Al powders. Subsequent experimental results indicate that both morphology and microstructure of as-annealed Fe-Si-Al powders change with increasing annealing temperature. Meanwhile, dielectric properties analysis suggesting that both real part ε‧ and imaginary part ε″ of the Fe-Si-Al powders decrease significantly after annealed at 450 °C or higher temperature. We assume that it's the precipitates with low electrical conductivity developed on the surface of powders that increase the surface resistivity of as-annealed powders and leading to a lower imagine part of permittivity. The drop of real part ε‧ ascribed to the weakened interfacial polarization which resulted from the decrease of structural defects such as grain boundaries and interfaces during annealing process.

  2. Annealing to reduce scattering centers in Czochralski-grown beta-BaB2O4.

    PubMed

    Kouta, H; Kuwano, Y

    1999-02-20

    When a visible laser beam passes through beta-BaB(2)O(4) (BBO), scattered light can be observed along the beam within the crystal. Scattering centers caused by structural defects in Czochralski-grown BBO can be reduced by 95% by annealing at 920 degrees C. In the flux-grown BBO, centers actually increase by the same annealing because the process causes microcracks and/or secondary inclusions. It is shown that annealed Czochralski-grown BBO is superior to flux-grown BBO (annealed or as-grown) in terms of optical loss. PMID:18305712

  3. Preparation of nickel oxide thin films at different annealing temperature by sol-gel spin coating method

    NASA Astrophysics Data System (ADS)

    Abdullah, M. A. R.; Mamat, M. H.; Ismail, A. S.; Malek, M. F.; Alrokayan, Salman A. H.; Khan, Haseeb A.; Rusop, M.

    2016-07-01

    Preparation of NiO thin films at different annealing temperature by sol-gel method was conducted to synthesize the quality of the surface thin films. The effects of annealing temperature on the surface topology were systematically investigated. Our studies confirmed that the surface roughness of the thin films was increased whenever annealing temperature was increase. NiO thin films morphology structure analysis was confirmed by field emission scanning electron microscope. Surface roughness of the thin films was investigated by atomic force microscopy.

  4. Making Art with Microscopes

    ERIC Educational Resources Information Center

    Benedis-Grab, Gregory

    2011-01-01

    Interdisciplinary teaching is a great way to focus on overarching concepts and help students make connections across disciplines. Historically, art and science have been connected disciplines. The botanical prints of the 18th and 19th centuries and early work with microscopes are two examples of a need for strong artistic skills in the science…

  5. Microscopic plasma Hamiltonian

    NASA Technical Reports Server (NTRS)

    Peng, Y.-K. M.

    1974-01-01

    A Hamiltonian for the microscopic plasma model is derived from the Low Lagrangian after the dual roles of the generalized variables are taken into account. The resulting Hamilton equations are shown to agree with the Euler-Lagrange equations of the Low Lagrangian.

  6. Microscope on Mars

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This image taken at Meridiani Planum, Mars by the panoramic camera on the Mars Exploration Rover Opportunity shows the rover's microscopic imager (circular device in center), located on its instrument deployment device, or 'arm.' The image was acquired on the ninth martian day or sol of the rover's mission.

  7. Microscopic analysis of Be,1110 elastic scattering on protons and nuclei, and breakup processes of 11Be within the 10Be +n cluster model

    NASA Astrophysics Data System (ADS)

    Lukyanov, V. K.; Kadrev, D. N.; Zemlyanaya, E. V.; Spasova, K.; Lukyanov, K. V.; Antonov, A. N.; Gaidarov, M. K.

    2015-03-01

    The density distributions of 10Be and 11Be nuclei obtained within the quantum Monte Carlo model and the generator coordinate method are used to calculate the microscopic optical potentials (OPs) and cross sections of elastic scattering of these nuclei on protons and 12C at energies E <100 MeV/nucleon. The real part of the OP is calculated using the folding model with the exchange terms included, while the imaginary part of the OP that reproduces the phase of scattering is obtained in the high-energy approximation. In this hybrid model of OP the free parameters are the depths of the real and imaginary parts obtained by fitting the experimental data. The well-known energy dependence of the volume integrals is used as a physical constraint to resolve the ambiguities of the parameter values. The role of the spin-orbit potential and the surface contribution to the OP is studied for an adequate description of available experimental elastic scattering cross-section data. Also, the cluster model, in which 11Be consists of a n -halo and the 10Be core, is adopted. Within the latter, the breakup cross sections of 11Be nucleus on 9Be,93Nb,181Ta , and 238U targets and momentum distributions of 10Be fragments are calculated and compared with the existing experimental data.

  8. Effect of annealing on the thermal properties of poly (lactic acid)/starch blends.

    PubMed

    Lv, Shanshan; Gu, Jiyou; Cao, Jun; Tan, Haiyan; Zhang, Yanhua

    2015-03-01

    A comparative study of the thermal behavior of PLA/starch blends annealed at different temperatures has been conducted. Annealing was found to be beneficial to weaken and even eliminate the enthalpy relaxation near Tg. The degree of crystallinity was evaluated by means of DSC, and the results showed that the crystallinity of the samples increased as the annealing temperatures were increased. It was observed that, during the annealing process, the disorder α (α') crystal modification tended to transform into the order α crystal modification. All of the PLA/starch blends showed a double melting behavior. With the increase of annealing temperatures, the lower Tm1 increased, while the Tm2 showed no evident change. The XRD patterns also showed that annealing was beneficial to the samples to form higher crystallinity. The TGA results indicated that the annealed samples did not show any higher thermal stability than the virgin samples. The activation energy calculated by the Flynn-Wall-Ozawa method at lower conversion degrees confirmed that the annealing slightly slowed the degradation. The activation energy did not show any dependence on the conversion degree, which indicated that there existed a complex degradation process of the PLA/starch blends. The average activation energy did not show obvious differences, indicating that the annealing treatment had little influence on the degradation activation energy. PMID:25542167

  9. Quantum Annealing for Constrained Optimization

    NASA Astrophysics Data System (ADS)

    Hen, Itay; Spedalieri, Federico M.

    2016-03-01

    Recent advances in quantum technology have led to the development and manufacturing of experimental programmable quantum annealers that promise to solve certain combinatorial optimization problems of practical relevance faster than their classical analogues. The applicability of such devices for many theoretical and real-world optimization problems, which are often constrained, is severely limited by the sparse, rigid layout of the devices' quantum bits. Traditionally, constraints are addressed by the addition of penalty terms to the Hamiltonian of the problem, which, in turn, requires prohibitively increasing physical resources while also restricting the dynamical range of the interactions. Here, we propose a method for encoding constrained optimization problems on quantum annealers that eliminates the need for penalty terms and thereby reduces the number of required couplers and removes the need for minor embedding, greatly reducing the number of required physical qubits. We argue the advantages of the proposed technique and illustrate its effectiveness. We conclude by discussing the experimental feasibility of the suggested method as well as its potential to appreciably reduce the resource requirements for implementing optimization problems on quantum annealers and its significance in the field of quantum computing.

  10. Simulated annealing model of acupuncture

    NASA Astrophysics Data System (ADS)

    Shang, Charles; Szu, Harold

    2015-05-01

    The growth control singularity model suggests that acupuncture points (acupoints) originate from organizers in embryogenesis. Organizers are singular points in growth control. Acupuncture can cause perturbation of a system with effects similar to simulated annealing. In clinical trial, the goal of a treatment is to relieve certain disorder which corresponds to reaching certain local optimum in simulated annealing. The self-organizing effect of the system is limited and related to the person's general health and age. Perturbation at acupoints can lead a stronger local excitation (analogous to higher annealing temperature) compared to perturbation at non-singular points (placebo control points). Such difference diminishes as the number of perturbed points increases due to the wider distribution of the limited self-organizing activity. This model explains the following facts from systematic reviews of acupuncture trials: 1. Properly chosen single acupoint treatment for certain disorder can lead to highly repeatable efficacy above placebo 2. When multiple acupoints are used, the result can be highly repeatable if the patients are relatively healthy and young but are usually mixed if the patients are old, frail and have multiple disorders at the same time as the number of local optima or comorbidities increases. 3. As number of acupoints used increases, the efficacy difference between sham and real acupuncture often diminishes. It predicted that the efficacy of acupuncture is negatively correlated to the disease chronicity, severity and patient's age. This is the first biological - physical model of acupuncture which can predict and guide clinical acupuncture research.

  11. Correlation of annealing with chemical stability in lyophilized pharmaceutical glasses.

    PubMed

    Luthra, Suman A; Hodge, Ian M; Utz, Marcel; Pikal, Michael J

    2008-12-01

    This research constitutes a thorough study of the relationship between the chemical stability, aging state and global molecular motion on the one hand, and microscopic local mobility in multi-component systems on the other hand. The objective of the present work was to determine whether annealing a glass below T(g) affects its chemical stability and determine if the rate of chemical degradation couples with global relaxation times determined using calorimetery, and/or with T(1) and T(1rho) relaxation times measured using ssNMR. Model compounds chosen for this research were lyophilized aspartame/sucrose and aspartame/trehalose (1:10 w/w) formulations. The chemical degradation was assessed at various temperatures using high-performance liquid chromatography (HPLC) to determine the impact of annealing on chemical stability. The rate constant for chemical degradation was estimated using stretched time kinetics. The results support the hypothesis that thermal history affects the molecular mobility required for structural relaxation and such effect is critical for chemical stability, that is, a stabilization effect upon annealing is observed. PMID:18481306

  12. Ballistic-Electron-Emission Microscope

    NASA Technical Reports Server (NTRS)

    Kaiser, William J.; Bell, L. Douglas

    1990-01-01

    Ballistic-electron-emission microscope (BEEM) employs scanning tunneling-microscopy (STM) methods for nondestructive, direct electrical investigation of buried interfaces, such as interface between semiconductor and thin metal film. In BEEM, there are at least three electrodes: emitting tip, biasing electrode, and collecting electrode, receiving current crossing interface under investigation. Signal-processing device amplifies electrode signals and converts them into form usable by computer. Produces spatial images of surface by scanning tip; in addition, provides high-resolution images of buried interface under investigation. Spectroscopic information extracted by measuring collecting-electrode current as function of one of interelectrode voltages.

  13. Solid-state optical microscope

    DOEpatents

    Young, I.T.

    1981-01-07

    A solid state optical microscope is described wherein wide-field and high-resolution images of an object are produced at a rapid rate by utilizing conventional optics with a charge-coupled photodiode array. Means for scanning in one of two orthogonal directions are provided, while the charge-coupled photodiode array scans in the other orthogonal direction. Illumination light from the object is incident upon the photodiodes, creating packets of electrons (signals) which are representative of the illuminated object. The signals are then processed, stored in a memory, and finally displayed as a video signal.

  14. A study on the orientation inheritance in laminated NiAl produced by in situ reaction annealing.

    PubMed

    Du, Yan; Fan, Guohua; Geng, Lin

    2016-04-01

    In order to promote the performance of B2 NiAl by texture control of orientation during in situ processing, phase transformation in laminated NiAl with bimodal grain size distribution manufactured by reaction annealing of Ni and Al foils has been studied. It turned out that there existed a Kurdjumov-Sachs orientation relationship (K-S OR) between parent Ni and product NiAl by crystallography analysis according to the electron backscatter diffraction (EBSD) results. The parent Ni did not transform to the product NiAl directly but via the formation of Ni3Al firstly according to the transmission electron microscope (TEM) observation of the interface. This led to a new K-S OR between Ni3Al and NiAl with a small atomic misfit, which made less residual stress generated through the formation of Ni3Al than directly from the parent Ni. PMID:26867210

  15. Shrinking of silicon nanocrystals embedded in an amorphous silicon oxide matrix during rapid thermal annealing in a forming gas atmosphere

    NASA Astrophysics Data System (ADS)

    van Sebille, M.; Fusi, A.; Xie, L.; Ali, H.; van Swaaij, R. A. C. M. M.; Leifer, K.; Zeman, M.

    2016-09-01

    We report the effect of hydrogen on the crystallization process of silicon nanocrystals embedded in a silicon oxide matrix. We show that hydrogen gas during annealing leads to a lower sub-band gap absorption, indicating passivation of defects created during annealing. Samples annealed in pure nitrogen show expected trends according to crystallization theory. Samples annealed in forming gas, however, deviate from this trend. Their crystallinity decreases for increased annealing time. Furthermore, we observe a decrease in the mean nanocrystal size and the size distribution broadens, indicating that hydrogen causes a size reduction of the silicon nanocrystals.

  16. On simulated annealing phase transitions in phylogeny reconstruction.

    PubMed

    Strobl, Maximilian A R; Barker, Daniel

    2016-08-01

    Phylogeny reconstruction with global criteria is NP-complete or NP-hard, hence in general requires a heuristic search. We investigate the powerful, physically inspired, general-purpose heuristic simulated annealing, applied to phylogeny reconstruction. Simulated annealing mimics the physical process of annealing, where a liquid is gently cooled to form a crystal. During the search, periods of elevated specific heat occur, analogous to physical phase transitions. These simulated annealing phase transitions play a crucial role in the outcome of the search. Nevertheless, they have received comparably little attention, for phylogeny or other optimisation problems. We analyse simulated annealing phase transitions during searches for the optimal phylogenetic tree for 34 real-world multiple alignments. In the same way in which melting temperatures differ between materials, we observe distinct specific heat profiles for each input file. We propose this reflects differences in the search landscape and can serve as a measure for problem difficulty and for suitability of the algorithm's parameters. We discuss application in algorithmic optimisation and as a diagnostic to assess parameterisation before computationally costly, large phylogeny reconstructions are launched. Whilst the focus here lies on phylogeny reconstruction under maximum parsimony, it is plausible that our results are more widely applicable to optimisation procedures in science and industry. PMID:27150349

  17. Annealing effects on optical properties of natural alexandrite

    NASA Astrophysics Data System (ADS)

    Fernandes Scalvi, Rosa M.; Li, Máximo Siu; Scalvi, Luis V. A.

    2003-11-01

    Natural alexandrite (BeAl2O4:Cr3+) crystals are investigated as regards the effects of annealing on their optical properties. Optical absorption spectra are measured from the ultraviolet (190 nm) to the near infrared (900 nm), for a sample subjected to consecutive annealing processes, where time and temperature are varied. Besides this, luminescence spectra are simultaneously obtained for this sample, excited with a Kr+ laser source, tuned on an ultraviolet multi-line mode (337.5, 350.7 and 356.4 nm). We observe from absorption as well as from emission data that annealing mainly influences the distribution of Cr3+ and Fe3+ ions, located on sites of a mirror plane (Cs symmetry), which are responsible for the optical properties of alexandrite. The results obtained lead to the conclusion that annealing induces a modification of the population of Cr3+ on Cs sites as well as on sites located on an inversion plane (Ci). Annealing could improve the optical properties of this material, as regards its application as a tunable laser.

  18. Characterization of the deformation and annealing of 304L stainless steel. Final report

    SciTech Connect

    Smith, W.H.

    1994-08-01

    Stainless steel, type 304L, was deformed at room temperature using the two processes of semi-piercing and cold-rolling and then annealed at various temperatures and times. The three metallurgical areas of work hardening, age hardening, and anneal softening were observed and characterized using metallography techniques of macrohardness, optical and transmission electron microscopy, and X-ray diffraction.

  19. Effect of annealing temperature on the structural and magnetic properties of CTAB-capped SrFe12O19 platelets

    NASA Astrophysics Data System (ADS)

    Harikrishnan, V.; Saravanan, P.; Ezhil Vizhi, R.; Babu, D. Rajan; Vinod, V. T. P.; Kejzlar, Pavel; Černík, Miroslav

    2016-03-01

    The use of surfactant such as cetyl-trimethyl ammonium bromide (CTAB) in producing highly coercive SrFe12O19 platelets is presented in this study. The synthesis of SrFe12O19 was accomplished by co-precipitation in presence of 1 wt% CTAB. The CTAB-coated precipitant thus obtained was subjected to annealing at different temperatures: 700, 800, 900 and 1000 °C. The annealed counterparts were characterized with respect to their structural and magnetic properties and the results are compared with that of those processed without CTAB. Thermogravimetry analysis was employed to study the thermo-chemical behavior for the SrFe12O19 samples. The evolution of crystalline phases as a function of annealing temperature was studied using x-ray diffraction. For the SrFe12O19 samples without CTAB, formation of α-Fe2O3 secondary phases are noticed at annealing temperatures of 700 and 800 °C; while such a secondary phase formation is not evident for the CTAB-capped SrFe12O19. Fourier transform infrared spectroscopy of the samples annealed at 1000 °C showed deformation in the structure due to the splitting of the bands. Both morphology and composition of the samples were examined by a field-emission scanning electron microscope attached with energy dispersive x-ray analysis. The morphology of CTAB-capped SrFe12O19 samples showed the presence of hexagonal platelets at higher annealing temperatures. The magnetic parameters such as saturation magnetization, MS and coercivity, HC were evaluated from the magnetic hysteresis loops obtained by vibrating sample magnetometer. Maximum values of HC (6.3 kOe) and MS (42.7 emu/g) were obtained for the CTAB-capped SrFe12O19 samples annealed at 900 °C. The possible mechanism on the formation of M-type hexagonal phase with platelet morphology using minimal amount of CTAB (1 wt%) in achieving high the HC values for the SrFe12O19 is discussed.

  20. Recursive Branching Simulated Annealing Algorithm

    NASA Technical Reports Server (NTRS)

    Bolcar, Matthew; Smith, J. Scott; Aronstein, David

    2012-01-01

    This innovation is a variation of a simulated-annealing optimization algorithm that uses a recursive-branching structure to parallelize the search of a parameter space for the globally optimal solution to an objective. The algorithm has been demonstrated to be more effective at searching a parameter space than traditional simulated-annealing methods for a particular problem of interest, and it can readily be applied to a wide variety of optimization problems, including those with a parameter space having both discrete-value parameters (combinatorial) and continuous-variable parameters. It can take the place of a conventional simulated- annealing, Monte-Carlo, or random- walk algorithm. In a conventional simulated-annealing (SA) algorithm, a starting configuration is randomly selected within the parameter space. The algorithm randomly selects another configuration from the parameter space and evaluates the objective function for that configuration. If the objective function value is better than the previous value, the new configuration is adopted as the new point of interest in the parameter space. If the objective function value is worse than the previous value, the new configuration may be adopted, with a probability determined by a temperature parameter, used in analogy to annealing in metals. As the optimization continues, the region of the parameter space from which new configurations can be selected shrinks, and in conjunction with lowering the annealing temperature (and thus lowering the probability for adopting configurations in parameter space with worse objective functions), the algorithm can converge on the globally optimal configuration. The Recursive Branching Simulated Annealing (RBSA) algorithm shares some features with the SA algorithm, notably including the basic principles that a starting configuration is randomly selected from within the parameter space, the algorithm tests other configurations with the goal of finding the globally optimal

  1. Annealing conditions for intrinsic CdTe

    NASA Astrophysics Data System (ADS)

    Berding, M. A.

    1999-01-01

    Equilibrium native defect densities in CdTe are calculated from ab initio methods, and compared with experimental results. We find that CdTe is highly compensated p type under tellurium-saturated conditions, with the cadmium vacancy as the dominant acceptor and the tellurium antisite as the compensating donor. This finding is in agreement with recent experiments that find a much larger deviation from stoichiometry than would be predicted by the electrically active defects. Under cadmium-saturated conditions, cadmium interstitials are predicted to dominate and the material is found to be n type. Native defect concentrations and the corresponding carrier concentrations are predicted as a function of processing conditions, and can serve as a guide to postgrowth anneals to manipulate the conductivity of undoped material for applications in x- and γ-ray spectrometers. Furthermore, we show that by choosing appropriate annealing conditions and extrinsic dopants, one can increase the operating efficiency of nuclear spectrometers by reducing the density of specific native defects that produce midgap trapping states.

  2. Annealing Would Improve beta" - Alumina Solid Electrolyte

    NASA Technical Reports Server (NTRS)

    Williams, Roger; Homer, Margie; Ryan, Margaret; Cortez, Roger; Shields, Virgil; Kisor, Adam

    2003-01-01

    A pre-operational annealing process is under investigation as a potential means of preventing a sudden reduction of ionic conductivity in a Beta"-alumina solid electrolyte (BASE) during use. On the basis of tests, the sudden reduction of ionic conductivity, followed by a slow recovery, has been found to occur during testing of the solid electrolyte and electrode components of an alkali metal thermal-to-electric converter (AMTEC) cell. At this time, high-temperature tests of limited duration have indicated the superiority of the treated BASE, but reproducible tests over thousands of hours are necessary to confirm that microcracking has been eliminated. The ionic conductivity of the treated BASE is also measured to be higher than untreated BASE at 1,073 K in low-pressure sodium vapor. Microcracking resulting in loss of conductivity was not observed with treated BASE in one high-temperature experiment, but this result must be duplicated over very long testing times to be sure of the effect. Shorter annealing times (10 to 20 hours) were found to result in significantly less loss of mass; it may be necessary for the packed powder mixture to evolve some Na2O before the Na2O can leave the ceramic.

  3. Multiresolution simulated annealing for brain image analysis

    NASA Astrophysics Data System (ADS)

    Loncaric, Sven; Majcenic, Zoran

    1999-05-01

    Analysis of biomedical images is an important step in quantification of various diseases such as human spontaneous intracerebral brain hemorrhage (ICH). In particular, the study of outcome in patients having ICH requires measurements of various ICH parameters such as hemorrhage volume and their change over time. A multiresolution probabilistic approach for segmentation of CT head images is presented in this work. This method views the segmentation problem as a pixel labeling problem. In this application the labels are: background, skull, brain tissue, and ICH. The proposed method is based on the Maximum A-Posteriori (MAP) estimation of the unknown pixel labels. The MAP method maximizes the a-posterior probability of segmented image given the observed (input) image. Markov random field (MRF) model has been used for the posterior distribution. The MAP estimation of the segmented image has been determined using the simulated annealing (SA) algorithm. The SA algorithm is used to minimize the energy function associated with MRF posterior distribution function. A multiresolution SA (MSA) has been developed to speed up the annealing process. MSA is presented in detail in this work. A knowledge-based classification based on the brightness, size, shape and relative position toward other regions is performed at the end of the procedure. The regions are identified as background, skull, brain, ICH and calcifications.

  4. Molecular dynamics simulation of annealed ZnO surfaces

    SciTech Connect

    Min, Tjun Kit; Yoon, Tiem Leong; Lim, Thong Leng

    2015-04-24

    The effect of thermally annealing a slab of wurtzite ZnO, terminated by two surfaces, (0001) (which is oxygen-terminated) and (0001{sup ¯}) (which is Zn-terminated), is investigated via molecular dynamics simulation by using reactive force field (ReaxFF). We found that upon heating beyond a threshold temperature of ∼700 K, surface oxygen atoms begin to sublimate from the (0001) surface. The ratio of oxygen leaving the surface at a given temperature increases as the heating temperature increases. A range of phenomena occurring at the atomic level on the (0001) surface has also been explored, such as formation of oxygen dimers on the surface and evolution of partial charge distribution in the slab during the annealing process. It was found that the partial charge distribution as a function of the depth from the surface undergoes a qualitative change when the annealing temperature is above the threshold temperature.

  5. Pressure Gradients and Annealing Effects in Solid Helium-4

    NASA Astrophysics Data System (ADS)

    Suhel, Md. Abdul Halim

    The Kim and Chan experiment in 2004 gave the first experimental evidence of a possible supersolid state. Even though the origin of this state is not clear yet, several experimental and theoretical investigations suggest defects are responsible for this curious phase. We have used heat pulses and thermal quenching to study pressure gradients and annealing mechanisms in solid 4He crystals. Large pressure gradients exist in crystals grown at constant volume. These can be enhanced by phase transitions, thermal quenching or by partial melting. Annealing reduces defect densities and hence pressure gradients in crystals. Our measurements show that the pressure at different points in a crystal can behave differently, even if there is little change in the crystal's average pressure. We measured the activation energy that is associated with the annealing process.

  6. Thermal annealing-induced electric dipole relaxation in natural alexandrite

    NASA Astrophysics Data System (ADS)

    Scalvi, Rosa M. Fernandes; Li, Maximo Siu; Scalvi, Luis V. A.

    2005-02-01

    Electrical properties of natural alexandrite (BeAl2O4:Cr3+) are investigated by the thermally stimulated depolarization current (TSDC) technique. Samples are submitted to consecutive annealing processes and TSDC is carried out after each annealing, yielding bands with different parameters. These bands are fitted by a continuous distribution of relaxation parameters: activation energy and pre-exponential factor of the Arrhenius equation. It has been observed that annealing influences the dipole relaxation behavior, since it promotes a modification of Fe3+ and Cr3+ impurity distributions on sites of distinct symmetry: Al1 and Al2. In order to have a reference for comparison, TSDC is also carried out on a synthetic alexandrite sample, where the only impurity present is Cr3+ ion.

  7. Error-corrected quantum annealing with hundreds of qubits

    NASA Astrophysics Data System (ADS)

    Pudenz, Kristen L.; Albash, Tameem; Lidar, Daniel A.

    2014-02-01

    Quantum information processing offers dramatic speedups, yet is susceptible to decoherence, whereby quantum superpositions decay into mutually exclusive classical alternatives, thus robbing quantum computers of their power. This makes the development of quantum error correction an essential aspect of quantum computing. So far, little is known about protection against decoherence for quantum annealing, a computational paradigm aiming to exploit ground-state quantum dynamics to solve optimization problems more rapidly than is possible classically. Here we develop error correction for quantum annealing and experimentally demonstrate it using antiferromagnetic chains with up to 344 superconducting flux qubits in processors that have recently been shown to physically implement programmable quantum annealing. We demonstrate a substantial improvement over the performance of the processors in the absence of error correction. These results pave the way towards large-scale noise-protected adiabatic quantum optimization devices, although a threshold theorem such as has been established in the circuit model of quantum computing remains elusive.

  8. Model for nonequilibrium segregation during pulsed laser annealing

    SciTech Connect

    Wood, R.F.

    1980-08-01

    Highly nonequilibrium thermodynamic processes occur during the ultrarapid recrystallization characteristic of pulsed laser annealing. Values of interface segregation coefficients are observed to differ from equilibrium values by as much as three orders of magnitude and equilibrium solubility limits may be exceeded by similar magnitudes. In this letter, a model is developed which accounts quantitatively for these effects.

  9. Femtosecond scanning tunneling microscope

    SciTech Connect

    Taylor, A.J.; Donati, G.P.; Rodriguez, G.; Gosnell, T.R.; Trugman, S.A.; Some, D.I.

    1998-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). By combining scanning tunneling microscopy with ultrafast optical techniques we have developed a novel tool to probe phenomena on atomic time and length scales. We have built and characterized an ultrafast scanning tunneling microscope in terms of temporal resolution, sensitivity and dynamic range. Using a novel photoconductive low-temperature-grown GaAs tip, we have achieved a temporal resolution of 1.5 picoseconds and a spatial resolution of 10 nanometers. This scanning tunneling microscope has both cryogenic and ultra-high vacuum capabilities, enabling the study of a wide range of important scientific problems.

  10. Ion photon emission microscope

    DOEpatents

    Doyle, Barney L.

    2003-04-22

    An ion beam analysis system that creates microscopic multidimensional image maps of the effects of high energy ions from an unfocussed source upon a sample by correlating the exact entry point of an ion into a sample by projection imaging of the ion-induced photons emitted at that point with a signal from a detector that measures the interaction of that ion within the sample. The emitted photons are collected in the lens system of a conventional optical microscope, and projected on the image plane of a high resolution single photon position sensitive detector. Position signals from this photon detector are then correlated in time with electrical effects, including the malfunction of digital circuits, detected within the sample that were caused by the individual ion that created these photons initially.

  11. Acoustic imaging microscope

    DOEpatents

    Deason, Vance A.; Telschow, Kenneth L.

    2006-10-17

    An imaging system includes: an object wavefront source and an optical microscope objective all positioned to direct an object wavefront onto an area of a vibrating subject surface encompassed by a field of view of the microscope objective, and to direct a modulated object wavefront reflected from the encompassed surface area through a photorefractive material; and a reference wavefront source and at least one phase modulator all positioned to direct a reference wavefront through the phase modulator and to direct a modulated reference wavefront from the phase modulator through the photorefractive material to interfere with the modulated object wavefront. The photorefractive material has a composition and a position such that interference of the modulated object wavefront and modulated reference wavefront occurs within the photorefractive material, providing a full-field, real-time image signal of the encompassed surface area.

  12. Microscopic enteritis: Bucharest consensus.

    PubMed

    Rostami, Kamran; Aldulaimi, David; Holmes, Geoffrey; Johnson, Matt W; Robert, Marie; Srivastava, Amitabh; Fléjou, Jean-François; Sanders, David S; Volta, Umberto; Derakhshan, Mohammad H; Going, James J; Becheanu, Gabriel; Catassi, Carlo; Danciu, Mihai; Materacki, Luke; Ghafarzadegan, Kamran; Ishaq, Sauid; Rostami-Nejad, Mohammad; Peña, A Salvador; Bassotti, Gabrio; Marsh, Michael N; Villanacci, Vincenzo

    2015-03-01

    Microscopic enteritis (ME) is an inflammatory condition of the small bowel that leads to gastrointestinal symptoms, nutrient and micronutrient deficiency. It is characterised by microscopic or sub-microscopic abnormalities such as microvillus changes and enterocytic alterations in the absence of definite macroscopic changes using standard modern endoscopy. This work recognises a need to characterize disorders with microscopic and submicroscopic features, currently regarded as functional or non-specific entities, to obtain further understanding of their clinical relevance. The consensus working party reviewed statements about the aetiology, diagnosis and symptoms associated with ME and proposes an algorithm for its investigation and treatment. Following the 5(th) International Course in Digestive Pathology in Bucharest in November 2012, an international group of 21 interested pathologists and gastroenterologists formed a working party with a view to formulating a consensus statement on ME. A five-step agreement scale (from strong agreement to strong disagreement) was used to score 21 statements, independently. There was strong agreement on all statements about ME histology (95%-100%). Statements concerning diagnosis achieved 85% to 100% agreement. A statement on the management of ME elicited agreement from the lowest rate (60%) up to 100%. The remaining two categories showed general agreement between experts on clinical presentation (75%-95%) and pathogenesis (80%-90%) of ME. There was strong agreement on the histological definition of ME. Weaker agreement on management indicates a need for further investigations, better definitions and clinical trials to produce quality guidelines for management. This ME consensus is a step toward greater recognition of a significant entity affecting symptomatic patients previously labelled as non-specific or functional enteropathy. PMID:25759526

  13. Focusing the surgical microscope.

    PubMed

    Socea, Sergiu D; Barak, Yoreh; Blumenthal, Eytan Z

    2015-01-01

    A well-focused operating microscope addresses several needs that are all secondary to the surgeon's need to see clearly at all times. These needs include: the assistant; the sharpness of the video and monitor; as well as field of view, asthenopia, and focusing issues related to zoom, accommodation, and presbyopia. We provide a practical approach to achieve optimal focus that we call the sloping paper calibration method. PMID:25891029

  14. Microscopic and macroscopic dynamics

    SciTech Connect

    Hoover, W.G.; Hoover, C.G.; De Groot, A.J.; Pierce, T.G. |

    1993-06-01

    Atomistic Molecular Dynamics and Lagrangian Continuum Mechanics can be very similarly adapted to massively-parallel computers. Millions of degrees of freedom can be treated. The two complementary approaches, microscopic and macroscopic, are being applied to increasingly realistic flows of fluids and solids. The two approaches can also be combined in a hybrid simulation scheme. Hybrids combine the fundamental constitutive advantage of atoms with the size advantage of the continuum picture.

  15. Microscopic enteritis: Bucharest consensus

    PubMed Central

    Rostami, Kamran; Aldulaimi, David; Holmes, Geoffrey; Johnson, Matt W; Robert, Marie; Srivastava, Amitabh; Fléjou, Jean-François; Sanders, David S; Volta, Umberto; Derakhshan, Mohammad H; Going, James J; Becheanu, Gabriel; Catassi, Carlo; Danciu, Mihai; Materacki, Luke; Ghafarzadegan, Kamran; Ishaq, Sauid; Rostami-Nejad, Mohammad; Peña, A Salvador; Bassotti, Gabrio; Marsh, Michael N; Villanacci, Vincenzo

    2015-01-01

    Microscopic enteritis (ME) is an inflammatory condition of the small bowel that leads to gastrointestinal symptoms, nutrient and micronutrient deficiency. It is characterised by microscopic or sub-microscopic abnormalities such as microvillus changes and enterocytic alterations in the absence of definite macroscopic changes using standard modern endoscopy. This work recognises a need to characterize disorders with microscopic and submicroscopic features, currently regarded as functional or non-specific entities, to obtain further understanding of their clinical relevance. The consensus working party reviewed statements about the aetiology, diagnosis and symptoms associated with ME and proposes an algorithm for its investigation and treatment. Following the 5th International Course in Digestive Pathology in Bucharest in November 2012, an international group of 21 interested pathologists and gastroenterologists formed a working party with a view to formulating a consensus statement on ME. A five-step agreement scale (from strong agreement to strong disagreement) was used to score 21 statements, independently. There was strong agreement on all statements about ME histology (95%-100%). Statements concerning diagnosis achieved 85% to 100% agreement. A statement on the management of ME elicited agreement from the lowest rate (60%) up to 100%. The remaining two categories showed general agreement between experts on clinical presentation (75%-95%) and pathogenesis (80%-90%) of ME. There was strong agreement on the histological definition of ME. Weaker agreement on management indicates a need for further investigations, better definitions and clinical trials to produce quality guidelines for management. This ME consensus is a step toward greater recognition of a significant entity affecting symptomatic patients previously labelled as non-specific or functional enteropathy. PMID:25759526

  16. Thermal Lens Microscope

    NASA Astrophysics Data System (ADS)

    Uchiyama, Kenji; Hibara, Akihide; Kimura, Hiroko; Sawada, Tsuguo; Kitamori, Takehiko

    2000-09-01

    We developed a novel laser microscope based on the thermal lens effect induced by a coaxial beam comprised of excitation and probe beams. The signal generation mechanism was confirmed to be an authentic thermal lens effect from the measurement of signal and phase dependences on optical configurations between the sample and the probe beam focus, and therefore, the thermal lens effect theory could be applied. Two-point spatial resolution was determined by the spot size of the excitation beam, not by the thermal diffusion length. Sensitivity was quite high, and the detection ability, evaluated using a submicron microparticle containing dye molecules, was 0.8 zmol/μm2, hence a distribution image of trace chemical species could be obtained quantitatively. In addition, analytes are not restricted to fluorescent species, therefore, the thermal lens microscope is a promising analytical microscope. A two-dimensional image of a histamine molecule distribution, which was produced in mast cells at the femtomole level in a human nasal mucous polyp, was obtained.

  17. Ion implantation doping and high temperature annealing of GaN

    SciTech Connect

    Zolper, J.C.; Crawford, M.H.; Howard, A.J. |

    1995-12-31

    The III-V nitride-containing semiconductors InN, GaN, and AIN and their ternary alloys are the focus of extensive research for application to visible light emitters and as the basis for high temperature electronics. Recent advances in ion implantation doping of GaN and studies of the effect of rapid thermal annealing up to 1100{degrees}C are making new device structures possible. Both p- and n-type implantation doping of GaN has been achieved using Mg co-implanted with P for p-type and Si-implantation for n-type. Electrical activation was achieved by rapid thermal anneals in excess of 1000{degrees}C. Atomic force microscopy studies of the surface of GaN after a series of anneals from 750 to 1100{degrees}C shows that the surface morphology gets smoother following anneals in Ar or N{sub 2}. The photoluminescence of the annealed samples also shows enhanced bandedge emission for both annealing ambients. For the deep level emission near 2.2 eV, the sample annealed in N{sub 2} shows slightly reduced emission while the sample annealed in Ar shows increased emission. These annealing results suggest a combination of defect interactions occur during the high temperature processing.

  18. Annealing Polymer Nanocomposite Fibers and Films Via Photothermal Heating: Effects On Overall Crystallinity and Morphology

    NASA Astrophysics Data System (ADS)

    Viswanath, Vidya

    Metal nanoparticles embedded within polymeric systems can act as localized heat sources, facilitating in situ polymer processing. When irradiated with light resonant with the nanoparticle's surface plasmon resonance (SPR), a non-equilibrium electron distribution is generated which rapidly transfers energy into the surrounding medium, resulting in a temperature increase in the immediate region around the particle. This work compares the utility of such photothermal heating versus traditional heating in two different polymeric media i.e. gold nanospheres/poly (ethylene oxide) (AuNP:PEO) nanocomposite films and electrospun nanofibers. Subsequently, a brief study on the usage of gold nanorods (AuNR) to anneal polymeric nanofibers and films has also been presented. Effect of annealing by conventional and photothermal methods has been studied for AuNP:PEO films crystallized from solution and the melt, which have been annealed at average sample temperatures above the glass transition and below the melting point. For all temperatures, photothermally annealed samples reached maximum crystallinity and maximum spherulite size at shorter annealing times. Percentage crystallinity change under conventional annealing was analyzed using time-temperature superposition (TTS). Comparison of the TTS data with results from photothermal experiments enabled determination of an "effective dynamic temperature" achieved under photothermal heating which is significantly higher than the average sample temperature. Thus, the heterogeneous temperature distribution created when annealing with the plasmon-mediated photothermal effect represents a unique tool to achieve processing outcomes that are not accessible via traditional annealing. In addition, the effect of annealing AuNP:PEO electrospun nanofibrous composites via conventional and photothermal annealing has also been studied. From the studies, it was observed that not only is the maximum crystallinity achieved more quickly when the

  19. Grain growth of gold nanowires through laser zone annealing and rapid thermal annealing

    NASA Astrophysics Data System (ADS)

    Kim, Jung Yun

    The grain boundary density in metals plays an increasingly important role as structures are shrinking down to dimensions comparable to the electronic mean free path. Metal nanowires prepared through electron beam lithography, electrodeposition and many other methods are nanocrystalline with an average grain diameter in the range of 2--50 nm. For these nanocrystalline metal nanowires with a lateral dimensions larger than the mean grain diameter, the electrical resistance is dominated by electron scattering at the grain boundaries as opposed to the external surfaces and the background. The deleterious effect of grain boundaries on the electrical properties provides strong motivation to develop post-processing methods for increasing the mean grain diameter. Thermal annealing has typically been used to induce grain growth. However, for metal nanowires patterned on a planar surface, a classic Rayleigh instability is observed resulting in decomposition of the nanowire to a periodic series of nanoparticles. In principle, grain growth requires short range motion of atoms while shape change requires mass displacement across large distances. Laser zone annealing was used to test whether the latter could be suppressed by rapidly heating a highly localized section of the wire followed by rapidly cooling. A piezoelectric motor was used to translate the wire at nanoscale steps over a 532 nm confocal laser source at range of power levels (2.5--10 mW) and translation rates (7--128 nm/s). Annealing at a laser power of 10 mW resulted in grain growth of nearly 300% from 27 nm to 85 nm. A second approach to inhibit shape change while allowing for grain growth was to encapsulate the nanowire with an alumina layer to constrict large scale atomic diffusion during isothermal annealing. The alumina coating maintained the shape of the nanowire up to a temperature of ˜669 K and grain growth approaching the limiting size was observed. To study the grain growth kinetics, in situ electrical

  20. Annealing to Mitigate Pitting in Electropolished Niobium Coupons and SRF Cavities

    SciTech Connect

    Cooley, L.D.; Hahn, E.; Hicks, D.; Romanenko, A.; Schuessler, R.; Thompson, C.; /Fermilab

    2011-06-08

    Ongoing studies at Fermilab investigate whether dislocations and other factors instigate pitting during cavity electropolishing (EP), despite careful processing controls and the inherent leveling mechanism of EP itself. Here, cold-worked niobium coupons, which exhibited increased tendencies for pitting in our past study, were annealed in a high vacuum furnace and subsequently processed by EP. Laser confocal scanning microscopy and special defect counting algorithms were used to assess the population of pits formed. Hardness measurements indicated that annealing for 2 hours at 800 C produced recovery, whereas annealing for 12 hours at 600 C did not, as is consistent with known changes for cavities annealed in a similar way. The 800 C anneal was effective in some cases but not others, and we discuss reasons why tendencies for pitting remain. We discuss implications for cavities and continued work to understand pitting.

  1. Effect of Annealing Treatment on Mechanical Properties of Nanocrystalline α-iron: an Atomistic Study

    PubMed Central

    Tong, Xuhang; Zhang, Hao; Li, D. Y.

    2015-01-01

    Claims are often found in the literature that metallic materials can be nanocrystallized by severe plastic deformation (SPD). However, SPD does not generate a well-defined nanocrystalline (NC) material, which can be achieved by subsequent annealing/recovery treatment. In this study, molecular dynamics (MD) simulation is employed to study the effect of annealing on structure and mechanical properties of cyclic deformed NC α-iron, which simulates SPD-processed α-iron. It is demonstrated that grain boundaries in the deformed NC α-iron evolve to a more equilibrium state during annealing, eliminating or minimizing the residual stress. The annealing treatment increases the system's strength by reducing dislocation emission sources, and improves material ductility through strengthening grain boundaries' resistance to intergranular cracks. The results indicate that the annealing treatment is an essential process for obtaining a well-defined NC structure with superior mechanical properties. PMID:25675978

  2. Polynomial phase masks for extending the depth of field of a microscope.

    PubMed

    Caron, Nicolas; Sheng, Yunlong

    2008-08-01

    A polynomial phase mask is designed and fabricated for enhancing the depth of field of a microscope by more than tenfold. A generic polynomial of degree 31 that consists of 16 odd power terms is optimized by simulated annealing with a realistic average modulation transfer function (MTF) iteratively set as the target MTF. Optical experimental results are shown. PMID:18670540

  3. Q: How do Microscopes Work?

    ERIC Educational Resources Information Center

    Zimov, Sarah

    2004-01-01

    Microscopes allow scientists to examine everyday objects in extraordinary ways. They provide high-resolution images that show objects in fine detail. This brief article describes the many types of microscopes and how they are used in different scientific venues.

  4. Impact of annealing on electrical properties of Cu2ZnSnSe4 absorber layers

    NASA Astrophysics Data System (ADS)

    Weiss, Thomas Paul; Redinger, Alex; Rey, Germain; Schwarz, Torsten; Spies, Maria; Cojocura-Mirédin, Oana; Choi, P.-P.; Siebentritt, Susanne

    2016-07-01

    Reported growth processes for kesterite absorber layers generally rely on a sequential process including a final high temperature annealing step. However, the impact and details for this annealing process vary among literature reports and little is known on its impact on electrical properties of the absorber. We used kesterite absorber layers prepared by a high temperature co-evaporation process to explicitly study the impact of two different annealing processes. From electrical characterization it is found that the annealing process incorporates a detrimental deep defect distribution. On the other hand, the doping density could be reduced leading to a better collection and a higher short circuit current density. The activation energy of the doping acceptor was studied with admittance spectroscopy and showed Meyer-Neldel behaviour. This indicates that the entropy significantly contributes to the activation energy.

  5. Comparing codes for error corrected quantum annealing

    NASA Astrophysics Data System (ADS)

    Mishra, Anurag; Albash, Tameem; Paz, Gerardo; Lidar, Daniel

    2015-03-01

    Previous work on the D-Wave Two (DW2) device has demonstrated the effectiveness of using error correction and suppression for quantum annealers. As the size of a quantum annealer increases, error correction becomes crucial for improved performance. We introduce a new type of code for error correction tailored to the hardware graph of the DW2, discuss the result of benchmarking this code on qubit chains, discuss various new decoding methods, and compare the performance to previous quantum annealing correction schemes.

  6. Quantum Annealing for Constrained Optimization

    NASA Astrophysics Data System (ADS)

    Hen, Itay; Spedalieri, Federico

    Recent advances in quantum technology have led to the development and manufacturing of experimental programmable quantum annealers that could potentially solve certain quadratic unconstrained binary optimization problems faster than their classical analogues. The applicability of such devices for many theoretical and practical optimization problems, which are often constrained, is severely limited by the sparse, rigid layout of the devices' quantum bits. Traditionally, constraints are addressed by the addition of penalty terms to the Hamiltonian of the problem, which in turn requires prohibitively increasing physical resources while also restricting the dynamical range of the interactions. Here we propose a method for encoding constrained optimization problems on quantum annealers that eliminates the need for penalty terms and thereby removes many of the obstacles associated with the implementation of these. We argue the advantages of the proposed technique and illustrate its effectiveness. We then conclude by discussing the experimental feasibility of the suggested method as well as its potential to boost the encodability of other optimization problems.

  7. Annealing of aromatic polyimide precursors

    NASA Technical Reports Server (NTRS)

    Wakelyn, N. T.

    1975-01-01

    A study has been made of the thermal behavior of polyimide precursors: an isomeric pair of crystals of the complex formed by p-phenylenediamine with the separated isomers of the di-isopropyl ester of pyromellitic acid. Specimens of this material were isothermally annealed in the temperature range 120 C to 170 C for periods of time up to 1 week. Although this temperature range is well below that customarily used for imidizations, the working hypothesis was that it would be more likely that a polymer embodying at least part of the precursor structure could be formed if the molecular motion was minimized to that actually required for the formation of the imide linkage. The progress of the annealing was followed by: infrared spectroscopy, differential thermal analysis, powder X-ray diffraction, and thermal gravimetric analysis. Single crystal X-ray analysis of the meta monomer yields a structure of chains of alternating acid and base and suggests that this monomer is amenable to polymerization with a minimum of geometrical disruption.

  8. Adirondack Under the Microscope

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This image was taken by the Mars Exploration Rover Spirit front hazard-identification camera after the rover's first post-egress drive on Mars Sunday, Jan. 15, 2004. Engineers drove the rover approximately 3 meters (10 feet) from the Columbia Memorial Station toward the first rock target, seen in the foreground. The football-sized rock was dubbed Adirondack because of its mountain-shaped appearance. Scientists have begun using the microscopic imager instrument at the end of the rover's robotic arm to examine the rock and understand how it formed.

  9. Photography with a Microscope

    NASA Astrophysics Data System (ADS)

    Rost, Fred; Oldfield, Ron

    2000-03-01

    This beautifully illustrated book describes the methods used to record images viewed through a microscope. The text describes the principles and practices of photomicrography, and is written for all who take photomicrographs, beginners and/or experienced practitioners. The authors describe techniques that may be applied to many disciplines for teaching, research, archives, or pleasure. The book includes chapters on standard photography, modern digital techniques, methods for improving contrast, and a short chapter on drawing. In addition to its value as a work of reference, the authors' clear, didactic style makes this book suitable as a textbook for courses in photomicrography and/or elementary light microscopy.

  10. Classical Simulated Annealing Using Quantum Analogues

    NASA Astrophysics Data System (ADS)

    La Cour, Brian R.; Troupe, James E.; Mark, Hans M.

    2016-08-01

    In this paper we consider the use of certain classical analogues to quantum tunneling behavior to improve the performance of simulated annealing on a discrete spin system of the general Ising form. Specifically, we consider the use of multiple simultaneous spin flips at each annealing step as an analogue to quantum spin coherence as well as modifications of the Boltzmann acceptance probability to mimic quantum tunneling. We find that the use of multiple spin flips can indeed be advantageous under certain annealing schedules, but only for long anneal times.

  11. Classical Simulated Annealing Using Quantum Analogues

    NASA Astrophysics Data System (ADS)

    La Cour, Brian R.; Troupe, James E.; Mark, Hans M.

    2016-06-01

    In this paper we consider the use of certain classical analogues to quantum tunneling behavior to improve the performance of simulated annealing on a discrete spin system of the general Ising form. Specifically, we consider the use of multiple simultaneous spin flips at each annealing step as an analogue to quantum spin coherence as well as modifications of the Boltzmann acceptance probability to mimic quantum tunneling. We find that the use of multiple spin flips can indeed be advantageous under certain annealing schedules, but only for long anneal times.

  12. Scanned optical fiber confocal microscope

    NASA Astrophysics Data System (ADS)

    Dickensheets, David L.; Kino, Gordon S.

    1994-04-01

    The size and weight of conventional optical microscopes often makes them inconvenient for use on the human body or for in-situ examination during materials processing. We describe a new fiber-optic scanning confocal optical microscope which could have a total outside diameter as small as 1 mm, and should lend itself to applications in endoscopy or to optical in vivo histology. The first experimental device utilizes a single-mode optical fiber for illumination and detection. The scanning element is a mechanically resonant fused silica cantilever 1.5 cm long and 0.8 mm across, with a micromachined two-phase zone plate objective mounted at one end. The cantilever is electrostatically scanned near resonance in two dimensions, generating a Lissajous pattern which is scan converted to conventional video for real time display or digitization. The objective lens has N.A. equals 0.25 at (lambda) equals 0.6328 micrometers , with a measured spot size of 1.8 micrometers FWHM.

  13. Electrochemically induced annealing of stainless-steel surfaces.

    PubMed

    Burstein, G T; Hutchings, I M; Sasaki, K

    2000-10-19

    Modification of the surface properties of metals without affecting their bulk properties is of technological interest in demanding applications where surface stability and hardness are important. When austenitic stainless steel is heavily plastically deformed by grinding or rolling, a martensitic phase transformation occurs that causes significant changes in the bulk and surface mechanical properties of the alloy. This martensitic phase can also be generated in stainless-steel surfaces by cathodic charging, as a consequence of lattice strain generated by absorbed hydrogen. Heat treatment of the steel to temperatures of several hundred degrees can result in loss of the martensitic structure, but this alters the bulk properties of the alloy. Here we show that martensitic structures in stainless steel can be removed by appropriate electrochemical treatment in aqueous solutions at much lower temperature than conventional annealing treatments. This electrochemically induced annealing process allows the hardness of cold-worked stainless steels to be maintained, while eliminating the brittle martensitic phase from the surface. Using this approach, we are able to anneal the surface and near-surface regions of specimens that contain rolling-induced martensite throughout their bulk, as well as those containing surface martensite induced by grinding. Although the origin of the electrochemical annealing process still needs further clarification, we expect that this treatment will lead to further development in enhancing the surface properties of metals. PMID:11057662

  14. Pulsed laser annealing of Be-implanted GaN

    SciTech Connect

    Wang, H.T.; Tan, L.S.; Chor, E.F.

    2005-11-01

    Postimplantation thermal processing of Be in molecular-beam-epitaxy-grown GaN by rapid thermal annealing (RTA) and pulsed laser annealing (PLA) was investigated. It has been found that the activation of Be dopants and the repair of implantation-induced defects in GaN films cannot be achieved efficiently by conventional RTA alone. On the other hand, good dopant activation and surface morphology and quality were obtained when the Be-implanted GaN film was annealed by PLA with a 248 nm KrF excimer laser. However, observations of off-resonant micro-Raman and high-resolution x-ray-diffraction spectra indicated that crystal defects and strain resulting from Be implantation were still existent after PLA, which probably degraded the carrier mobility and limited the activation efficiency to some extent. This can be attributed to the shallow penetration depth of the 248 nm laser in GaN, which only repaired the crystal defects in a thin near-surface layer, while the deeper defects were not annealed out well. This situation was significantly improved when the Be-implanted GaN was subjected to a combined process of PLA followed by RTA, which produced good activation of the dopants, good surface morphology, and repaired bulk and surface defects well.

  15. Direct Immersion Annealing of Block Copolymer Thin Films

    NASA Astrophysics Data System (ADS)

    Karim, Alamgir

    We demonstrate ordering of thin block copolymer (BCP) films via direct immersion annealing (DIA) at enhanced rate leading to stable morphologies. The BCP films are immersed in carefully selected mixtures of good and marginal solvents that can impart enhanced polymer mobility, while inhibiting film dissolution. DIA is compatible with roll-to-roll assembly manufacturing and has distinct advantages over conventional thermal annealing and batch processing solvent-vapor annealing methods. We identify three solvent composition-dependent BCP film ordering regimes in DIA for the weakly interacting polystyrene -poly(methyl methacrylate) (PS -PMMA) system: rapid short range order, optimal long-range order, and a film instability regime. Kinetic studies in the ``optimal long-range order'' processing regime as a function of temperature indicate a significant reduction of activation energy for BCP grain growth compared to oven annealing at conventional temperatures. An attractive feature of DIA is its robustness to ordering other BCP (e.g. PS-P2VP) and PS-PMMA systems exhibiting spherical, lamellar and cylindrical ordering. Inclusion of nanoparticles in these films at high concentrations and fast ordering kinetics study with neutron reflectivity and SANS will be discussed. This is (late) Contributed Talk Abstract for Dillon Medal Symposium at DPOLY - discussed with DPOLY Chair Dvora Perahia.

  16. Direct Immersion Annealing of Thin Block Copolymer Films.

    PubMed

    Modi, Arvind; Bhaway, Sarang M; Vogt, Bryan D; Douglas, Jack F; Al-Enizi, Abdullah; Elzatahry, Ahmed; Sharma, Ashutosh; Karim, Alamgir

    2015-10-01

    We demonstrate ordering of thin block copolymer (BCP) films via direct immersion annealing (DIA) at enhanced rate leading to stable morphologies. The BCP films are immersed in carefully selected mixtures of good and marginal solvents that can impart enhanced polymer mobility, while inhibiting film dissolution. DIA is compatible with roll-to-roll assembly manufacturing and has distinct advantages over conventional thermal annealing and batch processing solvent-vapor annealing methods. We identify three solvent composition-dependent BCP film ordering regimes in DIA for the weakly interacting polystyrene-poly(methyl methacrylate) (PS-PMMA) system: rapid short-range order, optimal long-range order, and a film instability regime. Kinetic studies in the "optimal long-range order" processing regime as a function of temperature indicate a significant reduction of activation energy for BCP grain growth compared to oven annealing at conventional temperatures. An attractive feature of DIA is its robustness to ordering other BCP (e.g. PS-P2VP) and PS-PMMA systems exhibiting spherical, lamellar and cylindrical ordering. PMID:26351823

  17. Surface faceting and elemental diffusion behaviour at atomic scale for alloy nanoparticles during in situ annealing

    PubMed Central

    Chi, Miaofang; Wang, Chao; Lei, Yinkai; Wang, Guofeng; Li, Dongguo; More, Karren L.; Lupini, Andrew; Allard, Lawrence F.; Markovic, Nenad M.; Stamenkovic, Vojislav R.

    2015-01-01

    The catalytic performance of nanoparticles is primarily determined by the precise nature of the surface and near-surface atomic configurations, which can be tailored by post-synthesis annealing effectively and straightforwardly. Understanding the complete dynamic response of surface structure and chemistry to thermal treatments at the atomic scale is imperative for the rational design of catalyst nanoparticles. Here, by tracking the same individual Pt3Co nanoparticles during in situ annealing in a scanning transmission electron microscope, we directly discern five distinct stages of surface elemental rearrangements in Pt3Co nanoparticles at the atomic scale: initial random (alloy) elemental distribution; surface platinum-skin-layer formation; nucleation of structurally ordered domains; ordered framework development and, finally, initiation of amorphization. Furthermore, a comprehensive interplay among phase evolution, surface faceting and elemental inter-diffusion is revealed, and supported by atomistic simulations. This work may pave the way towards designing catalysts through post-synthesis annealing for optimized catalytic performance. PMID:26576477

  18. Electron microscope phase enhancement

    DOEpatents

    Jin, Jian; Glaeser, Robert M.

    2010-06-15

    A microfabricated electron phase shift element is used for modifying the phase characteristics of an electron beam passing though its center aperture, while not affecting the more divergent portion of an incident beam to selectively provide a ninety-degree phase shift to the unscattered beam in the back focal plan of the objective lens, in order to realize Zernike-type, in-focus phase contrast in an electron microscope. One application of the element is to increase the contrast of an electron microscope for viewing weakly scattering samples while in focus. Typical weakly scattering samples include biological samples such as macromolecules, or perhaps cells. Preliminary experimental images demonstrate that these devices do apply a ninety degree phase shift as expected. Electrostatic calculations have been used to determine that fringing fields in the region of the scattered electron beams will cause a negligible phase shift as long as the ratio of electrode length to the transverse feature-size aperture is about 5:1. Calculations are underway to determine the feasibility of aspect smaller aspect ratios of about 3:1 and about 2:1.

  19. Microscopic Rayleigh Droplet Beams

    NASA Astrophysics Data System (ADS)

    Doak, R. B.

    2005-11-01

    A periodically triggered Rayleigh Droplet Beam (RDB) delivers a perfectly linear and periodic stream of identical, monoenergetic droplets that are phase-locked to the trigger signal. The droplet diameter and spacing are easily adjusted of choice of nozzle diameter and trigger frequency. Any liquid of low viscosity may be emloyed as the beam fluid. Although the field of nanofluidics is expanding rapidly, little effort has yet been devoted to ``external flows'' such as RDB's. At ASU we have generated RDB's of water and methanol down to 2 microns in droplet diameter. Nozzle clogging is the sole impediment to smaller droplets. Microscopic Rayleigh droplet beams offer tremendous potential for fundamental physical measurements, fluid dynamics research, and nanofabrication. This talk will describe the apparatus and techniques used at ASU to generate RDB's (surprisingly simple and inexpensive), discuss the triboelectric phenomena that play a role (surprisingly significant), present some initial experimental fluid dynamics measurements, and briefly survey RDB applications. Our particular interest in RDB's is as microscopic transport systems to deliver hydrated, undenatured proteins into vacuum for structure determination via serial diffraction of x-rays or electrons. This may offer the first general method for structure determination of non-crystallizable proteins.

  20. Forensic Scanning Electron Microscope

    NASA Astrophysics Data System (ADS)

    Keeley, R. H.

    1983-03-01

    The scanning electron microscope equipped with an x-ray spectrometer is a versatile instrument which has many uses in the investigation of crime and preparation of scientific evidence for the courts. Major applications include microscopy and analysis of very small fragments of paint, glass and other materials which may link an individual with a scene of crime, identification of firearms residues and examination of questioned documents. Although simultaneous observation and chemical analysis of the sample is the most important feature of the instrument, other modes of operation such as cathodoluminescence spectrometry, backscattered electron imaging and direct x-ray excitation are also exploited. Marks on two bullets or cartridge cases can be compared directly by sequential scanning with a single beam or electronic linkage of two instruments. Particles of primer residue deposited on the skin and clothing when a gun is fired can be collected on adhesive tape and identified by their morphology and elemental composition. It is also possible to differentiate between the primer residues of different types of ammunition. Bullets may be identified from the small fragments left behind as they pass through the body tissues. In the examination of questioned documents the scanning electron microscope is used to establish the order in which two intersecting ink lines were written and to detect traces of chemical markers added to the security inks on official documents.

  1. Studies on the annealing and antibacterial properties of the silver-embedded aluminum/silica nanospheres

    PubMed Central

    2014-01-01

    Substantial silver-embedded aluminum/silica nanospheres with uniform diameter and morphology were successfully synthesized by sol-gel technique. After various annealing temperatures, the surface mechanisms of each sample were analyzed using scanning electron microscope, transmission electron microscope, and X-ray photoelectron spectroscopy. The chemical durability examinations and antibacterial tests of each sample were also carried out for the confirmation of its practical usage. Based on the result of the above analyses, the silver-embedded aluminum/silica nanospheres are eligible for fabricating antibacterial utensils. PMID:25136275

  2. DOE`s annealing prototype demonstration projects

    SciTech Connect

    Warren, J.; Nakos, J.; Rochau, G.

    1997-02-01

    One of the challenges U.S. utilities face in addressing technical issues associated with the aging of nuclear power plants is the long-term effect of plant operation on reactor pressure vessels (RPVs). As a nuclear plant operates, its RPV is exposed to neutrons. For certain plants, this neutron exposure can cause embrittlement of some of the RPV welds which can shorten the useful life of the RPV. This RPV embrittlement issue has the potential to affect the continued operation of a number of operating U.S. pressurized water reactor (PWR) plants. However, RPV material properties affected by long-term irradiation are recoverable through a thermal annealing treatment of the RPV. Although a dozen Russian-designed RPVs and several U.S. military vessels have been successfully annealed, U.S. utilities have stated that a successful annealing demonstration of a U.S. RPV is a prerequisite for annealing a licensed U.S. nuclear power plant. In May 1995, the Department of Energy`s Sandia National Laboratories awarded two cost-shared contracts to evaluate the feasibility of annealing U.S. licensed plants by conducting an anneal of an installed RPV using two different heating technologies. The contracts were awarded to the American Society of Mechanical Engineers (ASME) Center for Research and Technology Development (CRTD) and MPR Associates (MPR). The ASME team completed its annealing prototype demonstration in July 1996, using an indirect gas furnace at the uncompleted Public Service of Indiana`s Marble Hill nuclear power plant. The MPR team`s annealing prototype demonstration was scheduled to be completed in early 1997, using a direct heat electrical furnace at the uncompleted Consumers Power Company`s nuclear power plant at Midland, Michigan. This paper describes the Department`s annealing prototype demonstration goals and objectives; the tasks, deliverables, and results to date for each annealing prototype demonstration; and the remaining annealing technology challenges.

  3. Reduction of Cu2O Islands Grown on a Cu(100) Surface through Vacuum Annealing

    NASA Astrophysics Data System (ADS)

    Zhou, Guangwen; Yang, Judith C.

    2004-11-01

    The reduction of Cu2O islands grown on Cu(100) surfaces through vacuum annealing was visualized by an in situ ultrahigh vacuum transmission electron microscope. The shrinkage of the island followed a linear decay behavior. The complete reduction of the oxide islands leads to the formation of nanoindentations on the Cu surfaces. A simple phenomenological kinetic model based on the dissociation along the island perimeter suitably describes the reduction behavior of the surface oxide islands.

  4. The effects of annealing a 2-dimensional array of ion-irradiated Josephson junctions

    NASA Astrophysics Data System (ADS)

    Cho, E. Y.; Kouperine, K.; Zhuo, Y.; Dynes, R. C.; Cybart, S. A.

    2016-09-01

    We have fabricated the two-dimensional arrays of superconducting quantum interference devices (SQUIDs) using YBa2Cu3O7-δ ion-irradiated Josephson junctions, and we have studied the effects of post-annealing the arrays at 100 ◦C in oxygen. The maximum voltage modulation, V B, in a magnetic field for DC biased arrays at 50 K is initially 1.2 mV, but increases to 3 mV after annealing. Furthermore, the temperature where the largest V B occurs increases from 45 K to 48.5 K after annealing. We present and simulate a model where annealing causes diffusion and recombination of the low-energy oxygen defects that narrows the barrier, resulting in an increase in the Josephson binding energy. We show that this process stabilizes after 40 minutes of annealing and leads to a significant improvement in the properties of the array.

  5. Picosecond and nanosecond laser annealing and simulation of amorphous silicon thin films for solar cell applications

    NASA Astrophysics Data System (ADS)

    Theodorakos, I.; Zergioti, I.; Vamvakas, V.; Tsoukalas, D.; Raptis, Y. S.

    2014-01-01

    In this work, a picosecond diode pumped solid state laser and a nanosecond Nd:YAG laser have been used for the annealing and the partial nano-crystallization of an amorphous silicon layer. These experiments were conducted as an alternative/complementary to plasma-enhanced chemical vapor deposition method for fabrication of micromorph tandem solar cell. The laser experimental work was combined with simulations of the annealing process, in terms of temperature distribution evolution, in order to predetermine the optimum annealing conditions. The annealed material was studied, as a function of several annealing parameters (wavelength, pulse duration, fluence), as far as it concerns its structural properties, by X-ray diffraction, SEM, and micro-Raman techniques.

  6. Selective aspect ratio of CNTs based on annealing temperature by TCVD method

    NASA Astrophysics Data System (ADS)

    Yousefi, Amin Termeh; Mahmood, Mohamad Rusop; Ikeda, Shoichiro

    2016-07-01

    Various aspect ratios of CNTs reported based on alteration of annealing temperature using thermal-chemical vapor deposition (TCVD) method. Also the growth dependent and independent parameters of the carbon nanotube (CNTs) array were studied as a function of synthesis method. The FESEM images indicate that the nanotubes are approximately perpendicular to the surface of the silicon substrate and form carbon nanotubes in different aspect ratios according to the applied annealing temperature. Furthermore, due to the optimized results it can be observed that, the mechanism of the CNTs growth is still present in the annealing step as well as deposition process and the most CNTs with crystalline aspect, produced in the annealing temperature, which was optimized at 700 - 900 ˚C. This result demonstrates that the growth rate, mass production, diameter, density, and crystallinity of CNT can be controlled by the annealing temperature.

  7. THz wave emission microscope

    NASA Astrophysics Data System (ADS)

    Yuan, Tao

    Sensing and imaging using Terahertz (THz) radiation has attracted more and more interest in the last two decades thanks to the abundant material 'finger prints' in the THz frequency range. The low photon energy also makes THz radiation an attractive tool for nondestructive evaluation of materials and devices, biomedical applications, security checks and explosive screening. Due to the long wavelength, the far-field THz wave optical systems have relatively low spatial resolution. This physical limitation confines THz wave sensing and imaging to mostly macro-size samples. To investigate local material properties or micro-size structures and devices, near-field technology has to be employed. In this dissertation, the Electro-Optical THz wave emission microscope is investigated. The basic principle is to focus the femtosecond laser to a tight spot on a thin THz emitter layer to produce a THz wave source with a similar size as the focus spot. The apparatus provides a method for placing a THz source with sub-wavelength dimension in the near-field range of the investigated sample. Spatial resolution to the order of one tenth of the THz wavelength is demonstrated by this method. The properties of some widely used THz wave emission materials under tight focused pump light are studied. As an important branch of THz time domain spectroscopy (THz-TDS), THz wave emission spectroscopy has been widely used as a tool to investigate the material physics, such as energy band structure, carrier dynamics, material nonlinear properties and dynamics. As the main work of this dissertation, we propose to combine the THz wave emission spectroscopy with scanning probe microscopy (SPM) to build a tip-assisted THz wave emission microscope (TATEM), which is a valuable extension to current SPM science and technology. Illuminated by a femtosecond laser, the biased SPM tip forms a THz wave source inside the sample beneath the tip. The source size is proportional to the apex size of the tip so

  8. Thermal stress modification in regenerated fiber Bragg grating via manipulation of glass transition temperature based on CO₂-laser annealing.

    PubMed

    Lai, Man-Hong; Lim, Kok-Sing; Gunawardena, Dinusha S; Yang, Hang-Zhou; Chong, Wu-Yi; Ahmad, Harith

    2015-03-01

    In this work, we have demonstrated thermal stress relaxation in regenerated fiber Bragg gratings (RFBGs) by using direct CO₂-laser annealing technique. After the isothermal annealing and slow cooling process, the Bragg wavelength of the RFBG has been red-shifted. This modification is reversible by re-annealing and rapid cooling. It is repeatable with different cooling process in the subsequent annealing treatments. This phenomenon can be attributed to the thermal stress modification in the fiber core by means of manipulation of glass transition temperature with different cooling rates. This finding in this investigation is important for accurate temperature measurement of RFBG in dynamic environment. PMID:25723423

  9. Ion implantation and laser annealing

    NASA Astrophysics Data System (ADS)

    Three ion implantation and laser annealing projects have been performed by ORNL through the DOE sponsored Seed Money Program. The research has contributed toward improving the characteristics of wear, hardness, and corrosion resistance of some metals and ceramics, as well as the electrical properties of semiconductors. The work has helped to spawn related research, at ORNL and elsewhere, concerning the relationships between microstructure and materials properties. ORNL research has resulted in major advances in extended life and non-corrosive artificial joints (hip and knee), high performance semiconductors, failure resistant ceramics (with potential energy applications), and solar cells. The success of the seed money projects was instrumental in the formation of ORNL's Surface Modification and Characterization Facility (SMAC). More than 60 universities and companies have participated in SMAC programs.

  10. Sensitivity enhancement using annealed polymer optical-fibre-based sensors for pressure sensing applications

    NASA Astrophysics Data System (ADS)

    Pospori, A.; Marques, C. A. F.; Sáez-Rodríguez, D.; Nielsen, K.; Bang, O.; Webb, D. J.

    2016-05-01

    Thermal annealing can be used to induce a permanent negative Bragg wavelength shift for polymer fibre grating sensors and it was originally used for multiplexing purposes. Recently, researchers showed that annealing can also provide additional benefits, such as strain and humidity sensitivity enhancement and augmented temperature operational range. The annealing process can change both the optical and mechanical properties of the fibre. In this paper, the annealing effects on the stress and force sensitivities of PMMA fibre Bragg grating sensors are investigated. The incentive for that investigation was an unexpected behaviour observed in an array of sensors which were used for liquid level monitoring. One sensor exhibited much lower pressure sensitivity and that was the only one that was not annealed. To further investigate the phenomenon, additional sensors were photo-inscribed and characterised with regard their stress and force sensitivities. Then, the fibres were annealed by placing them in hot water, controlling with that way the humidity factor. After annealing, stress and force sensitivities were measured again. The results show that the annealing can improve the stress and force sensitivity of the devices. This can provide better performing sensors for use in stress, force and pressure sensing applications.

  11. Control of optical and electrical properties of ZnO nanocrystals by nanosecond-laser annealing

    NASA Astrophysics Data System (ADS)

    Shimogaki, T.; Ofuji, T.; Tetsuyama, N.; Kawahara, H.; Higashihata, M.; Ikenoue, H.; Nakamura, D.; Okada, T.

    2014-03-01

    Effects of laser annealing on electrical and optical properties of Zinc oxide (ZnO) nanocrystals, which are expected as building blocks for optoelectronic devices, have been investigated in this study. In the case of fabricating p-n junction in single one-dimensional ZnO nanocrystal, phosphorus-ions implanted p-type ZnO nanocrystals were recrystallized and recovered in the optical properties by nanosecond-laser annealing using a KrF excimer laser. Antimony-doped p-type ZnO nanocrystals were synthesized by irradiating laminated structure which antimony thin film were deposited on ZnO nanocrystals with the laser beam. Additionally, it is possible to control the growth rate of ZnO nanowires by using laser annealing. Irradiating with pulsed laser a part of ZnO buffer layer deposited on the a-cut sapphire substrate, then ZnO nanowires were grown on the ZnO buffer layer by the nanoparticle assisted pulsed laser deposition method. As a result, the clear boundary of the laser annealed and non-laser annealed area was appeared. It was observed that ZnO nanowires were grown densely at non-laser annealed area, on the other hand, sparse ones were grown at the laser-annealed region. In this report, the possibility of laser annealing techniques to establish the stable and reliable fabrication process of ZnO nanowires-based LD and LED are discussed on the basis of experimental results.

  12. Effect of annealing temperature on the morphology and optical properties of PMMA films by spin-coating method

    NASA Astrophysics Data System (ADS)

    Aadila, A.; Afaah, A. N.; Asib, N. A. M.; Mohamed, R.; Rusop, M.; Khusaimi, Z.

    2016-07-01

    Poly(methyl methacrylate) (PMMA) films were deposited on glass substrate by sol-gel spin-coating method. The films were annealed for 10 minutes in furnace at different annealing temperature of room temperature, 50, 100, 150 and 200 °C. The effect of annealing temperatures to the surface and optical properties of PMMA films spin-coated on the substrate were investigated by Atomic Force Microscope (AFM) and Ultraviolet-Visible (UV-Vis) Spectroscopy. It was observed in AFM analysis all the annealed films show excellent smooth surface with zero roughness. All the samples demonstrate a high transmittance of 80% in UV region as shown in UV-Vis measurement. Highly transparent films indicate the films are good optical properties and could be applied in various optical applications and also in non-linear optics.

  13. Imaging arrangement and microscope

    DOEpatents

    Pertsinidis, Alexandros; Chu, Steven

    2015-12-15

    An embodiment of the present invention is an imaging arrangement that includes imaging optics, a fiducial light source, and a control system. In operation, the imaging optics separate light into first and second tight by wavelength and project the first and second light onto first and second areas within first and second detector regions, respectively. The imaging optics separate fiducial light from the fiducial light source into first and second fiducial light and project the first and second fiducial light onto third and fourth areas within the first and second detector regions, respectively. The control system adjusts alignment of the imaging optics so that the first and second fiducial light projected onto the first and second detector regions maintain relatively constant positions within the first and second detector regions, respectively. Another embodiment of the present invention is a microscope that includes the imaging arrangement.

  14. Embryos, microscopes, and society.

    PubMed

    Maienschein, Jane

    2016-06-01

    Embryos have different meanings for different people and in different contexts. Seen under the microscope, the biological embryo starts out as one cell and then becomes a bunch of cells. Gradually these divide and differentiate to make up the embryo, which in humans becomes a fetus at eight weeks, and then eventually a baby. At least, that happens in those cases that carry through normally and successfully. Yet a popular public perception imagines the embryo as already a little person in the very earliest stages of development, as if it were predictably to become an adult. In actuality, cells can combine, pull apart, and recombine in a variety of ways and still produce embryos, whereas most embryos never develop into adults at all. Biological embryos and popular imaginations of embryos diverge. This paper looks at some of the historical reasons for and social implications of that divergence. PMID:26996410

  15. Atomic Force Microscope Operation

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Click on image for animation (large file)

    This animation is a scientific illustration of the operation of NASA's Phoenix Mars Lander's Atomic Force Microscope, or AFM. The AFM is part of Phoenix's Microscopy, Electrochemistry, and Conductivity Analyzer, or MECA.

    The AFM is used to image the smallest Martian particles using a very sharp tip at the end of one of eight beams.

    The beam of the AFM is set into vibration and brought up to the surface of a micromachined silicon substrate. The substrate has etched in it a series of pits, 5 micrometers deep, designed to hold the Martian dust particles.

    The microscope then maps the shape of particles in three dimensions by scanning them with the tip.

    At the end of the animation is a 3D representation of the AFM image of a particle that was part of a sample informally called 'Sorceress.' The sample was delivered to the AFM on the 38th Martian day, or sol, of the mission (July 2, 2008).

    The image shows four round pits, only 5 microns in depth, that were micromachined into the silicon substrate.

    A Martian particle only one micrometer, or one millionth of a meter, across is held in the upper left pit.

    The rounded particle shown at the highest magnification ever seen from another world is a particle of the dust that cloaks Mars. Such dust particles color the Martian sky pink, feed storms that regularly envelop the planet and produce Mars' distinctive red soil.

    The AFM was developed by a Swiss-led consortium, with Imperial College London producing the silicon substrate that holds sampled particles.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  16. Multiphoton cryo microscope with sample temperature control

    NASA Astrophysics Data System (ADS)

    Breunig, H. G.; Uchugonova, A.; König, K.

    2013-02-01

    We present a multiphoton microscope system which combines the advantages of multiphoton imaging with precise control of the sample temperature. The microscope provides online insight in temperature-induced changes and effects in plant tissue and animal cells with subcellular resolution during cooling and thawing processes. Image contrast is based on multiphoton fluorescence intensity or fluorescence lifetime in the range from liquid nitrogen temperature up to +600°C. In addition, micro spectra from the imaged regions can be recorded. We present measurement results from plant leaf samples as well as Chinese hamster ovary cells.

  17. The influence of annealing temperature on the interface and photovoltaic properties of CdS/CdSe quantum dots sensitized ZnO nanorods solar cells.

    PubMed

    Qiu, Xiaofeng; Chen, Ling; Gong, Haibo; Zhu, Min; Han, Jun; Zi, Min; Yang, Xiaopeng; Ji, Changjian; Cao, Bingqiang

    2014-09-15

    Arrays of ZnO/CdS/CdSe core/shell nanocables with different annealing temperatures have been investigated for CdS/CdSe quantum dots sensitized solar cells (QDSSCs). CdS/CdSe quantum dots were synthesized on the surface of ZnO nanorods that serve as the scaffold via a simple ion-exchange approach. The uniform microstructure was verified by scanning electron microscope and transmission electron microscope. UV-Visible absorption spectrum and Raman spectroscopy analysis indicated noticeable influence of annealing temperature on the interface structural and optical properties of the CdS/CdSe layers. Particularly, the relationship between annealing temperatures and photovoltaic performance of the corresponding QDSSCs was investigated employing photovoltaic conversion, quantum efficiency and electrochemical impedance spectra. It is demonstrated that higher cell efficiency can be obtained by optimizing the annealing temperature through extending the photoresponse range and improving QD layer crystal quality. PMID:24998074

  18. Corrosion inhibition of stainless steel type AISI 304 by Mn coating and subsequent annealing with flow of nitrogen at different temperatures

    NASA Astrophysics Data System (ADS)

    Grayeli-Korpi, Ali-Reza; Savaloni, Hadi; Habibi, Maryam

    2013-07-01

    This work reports the enhancement of stainless steel corrosion resistance coated with Mn and post-annealed with flow of nitrogen at different annealing temperatures. Crystallographic variation of the samples by annealing temperature is studied by X-ray diffraction (XRD) while their surface morphology and surface roughness was obtained by means of atomic force microscope (AFM) and scanning electron microscope (SEM) analyses before and after corrosion test respectively. Elemental analysis of samples after corrosion test was investigated by energy dispersive spectroscope (EDS) analysis. The corrosion behaviour of the samples was evaluated by potentiodynamic polarization test in 0.6 M NaCl solution. A critical annealing temperature is found at which the highest corrosion resistance can be achieved. Correlation between corrosion resistance, structural and surface morphology results is obtained.

  19. High-temperature annealing of optical centers in type-I diamond

    SciTech Connect

    Collins, Alan T.; Connor, Alex; Ly, C.-H.; Shareef, Abdulla; Spear, Paul M.

    2005-04-15

    Diamonds previously subjected to radiation damage have been annealed at temperatures up to 1750 deg. C at ambient pressure, and at 2300 deg. C using a stabilizing pressure of 5 GPa. The results have been compared with those from similar measurements using natural brown diamonds. The investigation has led to an improved understanding of the commercial process for enhancing the color of brown diamonds by high-pressure, high-temperature (HPHT) annealing. The study has confirmed that the H4 center is less stable than the H3 center, and shown that the destruction of the H4 center in irradiated type-IaB diamonds coincides with the formation of a number of optical centers found to occur naturally in brown diamonds. In type-IaA diamonds the annealing out of the H1b absorption coincides with the production of H2 centers. Annealing measurements on brown diamonds indicate that the plastic deformation, associated with the brown color, occurred at a late stage in the diamonds' history. Optical centers, such as H3 and (N-V){sup -}, that are produced in brown diamonds by HPHT annealing, are destroyed by this process in irradiated dislocation-free diamonds. Formation of these centers during the HPHT annealing of brown diamonds occurs as a result of the release of vacancies from the dislocations, and the present results therefore indicate that the production of these centers is a dynamic process with the generation and annealing in competition.

  20. Microscopic dynamics of synchronization in driven colloids

    PubMed Central

    Juniper, Michael P.N.; Straube, Arthur V.; Besseling, Rut; Aarts, Dirk G.A.L.; Dullens, Roel P.A.

    2015-01-01

    Synchronization of coupled oscillators has been scrutinized for over three centuries, from Huygens' pendulum clocks to physiological rhythms. One such synchronization phenomenon, dynamic mode locking, occurs when naturally oscillating processes are driven by an externally imposed modulation. Typically only averaged or integrated properties are accessible, leaving underlying mechanisms unseen. Here, we visualize the microscopic dynamics underlying mode locking in a colloidal model system, by using particle trajectories to produce phase portraits. Furthermore, we use this approach to examine the enhancement of mode locking in a flexible chain of magnetically coupled particles, which we ascribe to breathing modes caused by mode-locked density waves. Finally, we demonstrate that an emergent density wave in a static colloidal chain mode locks as a quasi-particle, with microscopic dynamics analogous to those seen for a single particle. Our results indicate that understanding the intricate link between emergent behaviour and microscopic dynamics is key to controlling synchronization. PMID:25994921

  1. Universal tool microscope remanufacture based on CCD

    NASA Astrophysics Data System (ADS)

    Kang, Jian; Hu, Zhongxiang; Zhang, Xunming; Zhang, Jiaying

    2006-02-01

    To overcome the drawback of traditional universal tool microscopes, a remanufacturing scheme based on charge coupled devices (CCD) is proposed. In this paper, the remanufacturing of old tool microscopes is replaced gradually by CCD and grating ruler and the development of a novel measuring system designed to directly analyze image of the screw to be measured is discussed. For the analysis of image, such novel image processing methods as adaptive switching median (ASM) filter and edge detection based on the modified Sobel operator are designed. For the line detection algorithm, HOUGH transform also is used to measure the screw parameter. Experiments on screw images demonstrate that the scheme of remanufactured universal tool microscope is of feasibility and the proposed measurement is of validity.

  2. CHAMP - Camera, Handlens, and Microscope Probe

    NASA Technical Reports Server (NTRS)

    Mungas, G. S.; Beegle, L. W.; Boynton, J.; Sepulveda, C. A.; Balzer, M. A.; Sobel, H. R.; Fisher, T. A.; Deans, M.; Lee, P.

    2005-01-01

    CHAMP (Camera, Handlens And Microscope Probe) is a novel field microscope capable of color imaging with continuously variable spatial resolution from infinity imaging down to diffraction-limited microscopy (3 micron/pixel). As an arm-mounted imager, CHAMP supports stereo-imaging with variable baselines, can continuously image targets at an increasing magnification during an arm approach, can provide precision range-finding estimates to targets, and can accommodate microscopic imaging of rough surfaces through a image filtering process called z-stacking. Currently designed with a filter wheel with 4 different filters, so that color and black and white images can be obtained over the entire Field-of-View, future designs will increase the number of filter positions to include 8 different filters. Finally, CHAMP incorporates controlled white and UV illumination so that images can be obtained regardless of sun position, and any potential fluorescent species can be identified so the most astrobiologically interesting samples can be identified.

  3. CHAMP (Camera, Handlens, and Microscope Probe)

    NASA Technical Reports Server (NTRS)

    Mungas, Greg S.; Boynton, John E.; Balzer, Mark A.; Beegle, Luther; Sobel, Harold R.; Fisher, Ted; Klein, Dan; Deans, Matthew; Lee, Pascal; Sepulveda, Cesar A.

    2005-01-01

    CHAMP (Camera, Handlens And Microscope Probe)is a novel field microscope capable of color imaging with continuously variable spatial resolution from infinity imaging down to diffraction-limited microscopy (3 micron/pixel). As a robotic arm-mounted imager, CHAMP supports stereo imaging with variable baselines, can continuously image targets at an increasing magnification during an arm approach, can provide precision rangefinding estimates to targets, and can accommodate microscopic imaging of rough surfaces through a image filtering process called z-stacking. CHAMP was originally developed through the Mars Instrument Development Program (MIDP) in support of robotic field investigations, but may also find application in new areas such as robotic in-orbit servicing and maintenance operations associated with spacecraft and human operations. We overview CHAMP'S instrument performance and basic design considerations below.

  4. Microscopic dynamics of synchronization in driven colloids.

    PubMed

    Juniper, Michael P N; Straube, Arthur V; Besseling, Rut; Aarts, Dirk G A L; Dullens, Roel P A

    2015-01-01

    Synchronization of coupled oscillators has been scrutinized for over three centuries, from Huygens' pendulum clocks to physiological rhythms. One such synchronization phenomenon, dynamic mode locking, occurs when naturally oscillating processes are driven by an externally imposed modulation. Typically only averaged or integrated properties are accessible, leaving underlying mechanisms unseen. Here, we visualize the microscopic dynamics underlying mode locking in a colloidal model system, by using particle trajectories to produce phase portraits. Furthermore, we use this approach to examine the enhancement of mode locking in a flexible chain of magnetically coupled particles, which we ascribe to breathing modes caused by mode-locked density waves. Finally, we demonstrate that an emergent density wave in a static colloidal chain mode locks as a quasi-particle, with microscopic dynamics analogous to those seen for a single particle. Our results indicate that understanding the intricate link between emergent behaviour and microscopic dynamics is key to controlling synchronization. PMID:25994921

  5. The annealing effects of V-doped GaN thin films grown by MOCVD

    NASA Astrophysics Data System (ADS)

    Souissi, M.; Bouzidi, M.; El Jani, B.

    2012-02-01

    We have investigated the annealing effect of V-doped GaN (GaN:V) epitaxial layers grown on sapphire by metal organic chemical vapor deposition (MOCVD). The film was annealed at a temperature of 1075 °C for 30 min in N 2 ambient after growth. The structural, surface morphology and optical properties of GaN:V films were studied by high resolution X-ray diffraction (HRXRD), atomic force microscope (AFM) and photoluminescence (PL). The results show that the annealing makes for the destruction in the crystal quality and surface morphology. After thermal annealing, the photoluminescence (PL) measurement showed a reduction of the blue luminescence (BL) band observed in GaN:V at room temperature (RT). The phenomenon is attributed to vanadium diffusion or to the V-related complex dissociation. Near-band-edge (NBE) peak exhibited a red shift after 1075 °C anneal. This is due to the decrease in the level of strain. In the infrared region, we observed the emergence of the line 0.93 eV accompanied by a decrease in the intensity of the 0.82 eV emission. Their possible origins are discussed.

  6. Formation of nanometer embedded phases during high-energy Ti-implanted and annealed steel

    NASA Astrophysics Data System (ADS)

    Zhang, Tonghe; Wu, Yuguang; Deng, Zhiwei; Cui, Ping; Wang, Ping

    2000-06-01

    Observation by transmission electron microscope (TEM) indicated the formation of FeTi 2 phase of 3.5-20 nm in diameter embedded in a high-energy Ti-implanted layer. The nanometer phases were embedded among dislocations and grain boundaries in Ti-implanted steel at 400°C. It has good wear resistance. The embedded structure changes after annealing. The structure changed slightly after annealing at temperature ranging from 350°C to 500°C, while the hardness of the implanted layer increased greatly. The maximum of hardness is obtained when the sample was annealed at 500°C for 20 min and the Ti phases had an average diameter of 8 nm. Dislocations disappeared and the diameter of nanometer phases increased to 10 and 16 nm after annealing at temperature of 750°C and 1000°C, respectively. The average densities of the nanometer phases are 8.8×10 10 and 6.5×10 10 cm-2, respectively for both annealing temperatures.

  7. Proper alignment of the microscope.

    PubMed

    Rottenfusser, Rudi

    2013-01-01

    The light microscope is merely the first element of an imaging system in a research facility. Such a system may include high-speed and/or high-resolution image acquisition capabilities, confocal technologies, and super-resolution methods of various types. Yet more than ever, the proverb "garbage in-garbage out" remains a fact. Image manipulations may be used to conceal a suboptimal microscope setup, but an artifact-free image can only be obtained when the microscope is optimally aligned, both mechanically and optically. Something else is often overlooked in the quest to get the best image out of the microscope: Proper sample preparation! The microscope optics can only do its job when its design criteria are matched to the specimen or vice versa. The specimen itself, the mounting medium, the cover slip, and the type of immersion medium (if applicable) are all part of the total optical makeup. To get the best results out of a microscope, understanding the functions of all of its variable components is important. Only then one knows how to optimize these components for the intended application. Different approaches might be chosen to discuss all of the microscope's components. We decided to follow the light path which starts with the light source and ends at the camera or the eyepieces. To add more transparency to this sequence, the section up to the microscope stage was called the "Illuminating Section", to be followed by the "Imaging Section" which starts with the microscope objective. After understanding the various components, we can start "working with the microscope." To get the best resolution and contrast from the microscope, the practice of "Koehler Illumination" should be understood and followed by every serious microscopist. Step-by-step instructions as well as illustrations of the beam path in an upright and inverted microscope are included in this chapter. A few practical considerations are listed in Section 3. PMID:23931502

  8. Transmission electron microscope CCD camera

    DOEpatents

    Downing, Kenneth H.

    1999-01-01

    In order to improve the performance of a CCD camera on a high voltage electron microscope, an electron decelerator is inserted between the microscope column and the CCD. This arrangement optimizes the interaction of the electron beam with the scintillator of the CCD camera while retaining optimization of the microscope optics and of the interaction of the beam with the specimen. Changing the electron beam energy between the specimen and camera allows both to be optimized.

  9. Annealing-induced change in quantum dot chain formation mechanism

    NASA Astrophysics Data System (ADS)

    Park, Tyler D.; Colton, John S.; Farrer, Jeffrey K.; Yang, Haeyeon; Kim, Dong Jun

    2014-12-01

    Self-assembled InGaAs quantum dot chains were grown using a modified Stranski-Krastanov method in which the InGaAs layer is deposited under a low growth temperature and high arsenic overpressure, which suppresses the formation of dots until a later annealing process. The dots are capped with a 100 nm GaAs layer. Three samples, having three different annealing temperatures of 460°C, 480°C, and 500°C, were studied by transmission electron microscopy. Results indicate two distinct types of dot formation processes: dots in the 460°C and 480°C samples form from platelet precursors in a one-to-one ratio whereas the dots in the sample annealed at 500°C form through the strain-driven self-assembly process, and then grow larger via an additional Ostwald ripening process whereby dots grow into larger dots at the expense of smaller seed islands. There are consequently significant morphological differences between the two types of dots, which explain many of the previously-reported differences in optical properties. Moreover, we also report evidence of indium segregation within the dots, with little or no indium intermixing between the dots and the surrounding GaAs barrier.

  10. Annealing-induced change in quantum dot chain formation mechanism

    SciTech Connect

    Park, Tyler D.; Colton, John S.; Farrer, Jeffrey K.; Yang, Haeyeon; Kim, Dong Jun

    2014-12-15

    Self-assembled InGaAs quantum dot chains were grown using a modified Stranski-Krastanov method in which the InGaAs layer is deposited under a low growth temperature and high arsenic overpressure, which suppresses the formation of dots until a later annealing process. The dots are capped with a 100 nm GaAs layer. Three samples, having three different annealing temperatures of 460°C, 480°C, and 500°C, were studied by transmission electron microscopy. Results indicate two distinct types of dot formation processes: dots in the 460°C and 480°C samples form from platelet precursors in a one-to-one ratio whereas the dots in the sample annealed at 500°C form through the strain-driven self-assembly process, and then grow larger via an additional Ostwald ripening process whereby dots grow into larger dots at the expense of smaller seed islands. There are consequently significant morphological differences between the two types of dots, which explain many of the previously-reported differences in optical properties. Moreover, we also report evidence of indium segregation within the dots, with little or no indium intermixing between the dots and the surrounding GaAs barrier.

  11. Athena microscopic Imager investigation

    USGS Publications Warehouse

    Herkenhoff, K. E.; Squyres, S. W.; Bell, J.F., III; Maki, J.N.; Arneson, H.M.; Bertelsen, P.; Brown, D.I.; Collins, S.A.; Dingizian, A.; Elliott, S.T.; Goetz, W.; Hagerott, E.C.; Hayes, A.G.; Johnson, M.J.; Kirk, R.L.; McLennan, S.; Morris, R.V.; Scherr, L.M.; Schwochert, M.A.; Shiraishi, L.R.; Smith, G.H.; Soderblom, L.A.; Sohl-Dickstein, J. N.; Wadsworth, M.V.

    2003-01-01

    The Athena science payload on the Mars Exploration Rovers (MER) includes the Microscopic Imager (MI). The MI is a fixed-focus camera mounted on the end of an extendable instrument arm, the Instrument Deployment Device (IDD). The MI was designed to acquire images at a spatial resolution of 30 microns/pixel over a broad spectral range (400-700 nm). The MI uses the same electronics design as the other MER cameras but has optics that yield a field of view of 31 ?? 31 mm across a 1024 ?? 1024 pixel CCD image. The MI acquires images using only solar or skylight illumination of the target surface. A contact sensor is used to place the MI slightly closer to the target surface than its best focus distance (about 66 mm), allowing concave surfaces to be imaged in good focus. Coarse focusing (???2 mm precision) is achieved by moving the IDD away from a rock target after the contact sensor has been activated. The MI optics are protected from the Martian environment by a retractable dust cover. The dust cover includes a Kapton window that is tinted orange to restrict the spectral bandpass to 500-700 nm, allowing color information to be obtained by taking images with the dust cover open and closed. MI data will be used to place other MER instrument data in context and to aid in petrologic and geologic interpretations of rocks and soils on Mars. Copyright 2003 by the American Geophysical Union.

  12. Microscopic Chondritic Chemical Reactors

    NASA Astrophysics Data System (ADS)

    Maurette, Michel

    Maurette (1998a and 1998b) gives a more detailed discussion of previous works supporting the role of unmelted micrometeorites in prebiotic chemistry. Krueger and Kissel (1987) quoted thermodynamic computations suggesting that the μm-size C-rich grains that they discovered in the tail of Halley’s comet with their time-of-flight mass spectrometer on board the Vega spacecraft, when added to a prebiotic soup of organics, could trigger the formation of nucleic acids. Anders (1989) relied on the characteristics of the tiny stratospheric micrometeorites with sizes of about 5 15 μm, which amount to less than about 1% of the micrometeorite mass flux, to argue that micrometeorites played a major role in the delivery of organics to the Earth. As first quoted by Ponchelet (1989), we proposed in 1989 that much larger micrometeorites, similar to Antarctic micrometeorites, might have been functioning as individual microscopic chemical reactors on the early Earth during their interactions with gases and waters (Maurette et al., 1990, 1991b, 1998a, 1998b). Subsequently, Chyba and Sagan (1992) ceased fully supporting the role of the direct impact of comets in the delivery of such organics, and started to refer that of micrometeorites.

  13. The microscope mission

    NASA Astrophysics Data System (ADS)

    Touboul, Pierre; Foulon, Bernard; Lafargue, Laurent; Metris, Gilles

    2002-04-01

    The MICROSCOPE mission had been selected at the end of 1999 by the French space agency Cnes for a launch scheduled in 2004. The scientific objective of the mission is the test of the Equivalence Principle (EP) up to an accuracy of 10 -15 with its well-known manifestation, the universality of free fall. This principle, at the origin of general relativity, is only consolidated by experimental results and presently with an accuracy of several 10 -13. The micro-satellite developed by Cnes weighs less than 120 kg and is compatible with a low-cost launch like ASAP ARIANE V. The instrument is composed of two differential electrostatic accelerometers operating at finely stabilised room temperature. Each accelerometer includes two cylindrical and concentric test masses, made of platinum or titanium alloys. The experiment consists in controlling the two masses in the same orbital motion. Because of the drag compensation system of the satellite including field effect electrical thrusters, this motion is quite purely gravitational. The electrostatic control forces used in the differential accelerometers are finely measured. The principle of the experiment is presented, the configuration of the instrument and of the satellite is detailed with regard to the present development status. The specifications for the major parameters of the experiment are detailed.

  14. Precision Laser Annealing of Focal Plane Arrays

    SciTech Connect

    Bender, Daniel A.; DeRose, Christopher; Starbuck, Andrew Lea; Verley, Jason C.; Jenkins, Mark W.

    2015-09-01

    We present results from laser annealing experiments in Si using a passively Q-switched Nd:YAG microlaser. Exposure with laser at fluence values above the damage threshold of commercially available photodiodes results in electrical damage (as measured by an increase in photodiode dark current). We show that increasing the laser fluence to values in excess of the damage threshold can result in annealing of a damage site and a reduction in detector dark current by as much as 100x in some cases. A still further increase in fluence results in irreparable damage. Thus we demonstrate the presence of a laser annealing window over which performance of damaged detectors can be at least partially reconstituted. Moreover dark current reduction is observed over the entire operating range of the diode indicating that device performance has been improved for all values of reverse bias voltage. Additionally, we will present results of laser annealing in Si waveguides. By exposing a small (<10 um) length of a Si waveguide to an annealing laser pulse, the longitudinal phase of light acquired in propagating through the waveguide can be modified with high precision, <15 milliradian per laser pulse. Phase tuning by 180 degrees is exhibited with multiple exposures to one arm of a Mach-Zehnder interferometer at fluence values below the morphological damage threshold of an etched Si waveguide. No reduction in optical transmission at 1550 nm was found after 220 annealing laser shots. Modeling results for laser annealing in Si are also presented.

  15. Colour annealing - a toy model of colour reconnections

    SciTech Connect

    Sandhoff, Marisa; Skands, Peter; /Fermilab

    2005-12-01

    We present a simple toy model for colour reconnections at the nonperturbative level. The model resembles an annealing-type algorithm and is applicable to any collider and process type, though we argue for a possible enhancement of the effect in hadron-hadron collisions. We present a simple application and study of the consequences for semileptonic t{bar t} events at the Tevatron.

  16. Embedding parameters for Quantum Annealing

    NASA Astrophysics Data System (ADS)

    Venturelli, Davide

    Many optimization problems are defined on highly connected graphs and many interesting physical spin-glass systems are featuring long-range interactions. One method to solve for the optimum/ground state is quantum annealing (QA). Most architectures for QA devices, manufactured or proposed, are based on optimizing Hamiltonians having spins connected in a non-complete graph, with nodes with a small maximum degree, compared to the requirements. To overcome this limitation 'embedding' is employed: the native graph is 'tiled' with ferromagnetic chains of spins that now are meant to represent the logical binary variables. While it is known how the strength of the ferromagnetic bonds can ensure that the classical Ising ground state of the embedded system can be univocally mapped to the ground state of the original system, there is very little study on the impact of these parameters on QA. Programmers have taken conservative choices for the parameters and the common practices can be improved. Starting from the physics of connected ferromagnetic Ising chains, we will review several parameter choices and discuss previous and new results obtained on the D-Wave 2X machine, on carefully designed problems that allow to isolate and evaluate the role of connectivity in embedded systems.

  17. Arsenic ambient conditions preventing surface degradation of GaAs during capless annealing at high temperatures

    NASA Technical Reports Server (NTRS)

    Kang, C. H.; Kondo, K.; Lagowski, J.; Gatos, H. C.

    1987-01-01

    Changes in surface morphology and composition caused by capless annealing of GaAs were studied as a function of annealing temperature, T(GaAs), and the ambient arsenic pressure controlled by the temperature, T(As), of an arsenic source in the annealing ampul. It was established that any degradation of the GaAs surface morphology could be completely prevented, providing that T(As) was more than about 0.315T(GaAs) + 227 C. This empirical relationship is valid up to the melting point temperature of GaAs (1238 C), and it may be useful in some device-processing steps.

  18. Excimer laser annealing to fabricate low cost solar cells

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The objective is to show whether or not pulsed excimer laser annealing (PELA) of ion-implanted junctions is a cost effective replacement for diffused junctions in fabricating crystalline silicon solar cells. The preliminary economic analysis completed shows that the use of PELA to fabricate both the front junction and back surface field (BSF) would cost approximately 35 cents per peak watt (Wp), compared to a cost of 15 cents/Wp for diffusion, aluminum BSF and an extra cleaning step in the baseline process. The cost advantage of the PELA process depends on improving the average cell efficiency from 14% to 16%, which would lower the overall cost of the module by about 15 cents/Wp. An optimized PELA process compatible with commercial production is to be developed, and increased cell efficiency with sufficient product for adequate statistical analysis demonstrated. An excimer laser annealing station was set-up and made operational. The first experiment used 248 nm radiation to anneal phosphorus implants in polished and texture-etched silicon.

  19. Compact Microscope Imaging System with Intelligent Controls

    NASA Technical Reports Server (NTRS)

    McDowell, Mark

    2004-01-01

    The figure presents selected views of a compact microscope imaging system (CMIS) that includes a miniature video microscope, a Cartesian robot (a computer- controlled three-dimensional translation stage), and machine-vision and control subsystems. The CMIS was built from commercial off-the-shelf instrumentation, computer hardware and software, and custom machine-vision software. The machine-vision and control subsystems include adaptive neural networks that afford a measure of artificial intelligence. The CMIS can perform several automated tasks with accuracy and repeatability . tasks that, heretofore, have required the full attention of human technicians using relatively bulky conventional microscopes. In addition, the automation and control capabilities of the system inherently include a capability for remote control. Unlike human technicians, the CMIS is not at risk of becoming fatigued or distracted: theoretically, it can perform continuously at the level of the best human technicians. In its capabilities for remote control and for relieving human technicians of tedious routine tasks, the CMIS is expected to be especially useful in biomedical research, materials science, inspection of parts on industrial production lines, and space science. The CMIS can automatically focus on and scan a microscope sample, find areas of interest, record the resulting images, and analyze images from multiple samples simultaneously. Automatic focusing is an iterative process: The translation stage is used to move the microscope along its optical axis in a succession of coarse, medium, and fine steps. A fast Fourier transform (FFT) of the image is computed at each step, and the FFT is analyzed for its spatial-frequency content. The microscope position that results in the greatest dispersal of FFT content toward high spatial frequencies (indicating that the image shows the greatest amount of detail) is deemed to be the focal position.

  20. The Latest in Handheld Microscopes

    ERIC Educational Resources Information Center

    Wighting, Mervyn J.; Lucking, Robert A.; Christmann, Edwin P.

    2004-01-01

    Around 1590, Zacharias Jansenn of Holland invented the microscope. Jansenn, an eyeglass maker by trade, experimented with lenses and discovered that things appeared closer with combinations of lenses. Over the past 400 years, several refinements to microscopes have occurred, making it possible to magnify objects between 200 and 1,500 times their…

  1. Scientists View Battery Under Microscope

    SciTech Connect

    2015-04-10

    PNNL researchers use a special microscope setup that shows the inside of a battery as it charges and discharges. This battery-watching microscope is located at EMSL, DOE's Environmental Molecular Sciences Laboratory that resides at PNNL. Researchers the world over can visit EMSL and use special instruments like this, many of which are the only one of their kind available to scientists.

  2. Kinetics of hardness evolution during annealing of gamma-irradiated polycarbonate

    SciTech Connect

    Yeh, S. H.; Chen, P. Y.; Lee, Sanboh; Harmon, Julie

    2012-12-01

    This study focuses on the evolution in microhardness values that accompany isothermal annealing in gamma-irradiated polycarbonate (PC). Hardness increases with increasing annealing time, temperature, and gamma radiation dose. A model composed of a mixture of first and zero order structure relaxation is proposed to interpret the hardness data. The rate constant data fit the Arrhenius equation, and the corresponding activation energy decreases with increasing dose. The extent of structural relaxation that controls the hardness in post-annealed PC increases with increasing annealing temperature and dose. The model demonstrates that hardness evolution in PC is an endothermic process. By contrast, when the model is applied to irradiated poly(methyl methacrylate) and hydroxyethyl methacrylate copolymer, hardness evolution is an exothermic process.

  3. First application of quantum annealing to IMRT beamlet intensity optimization

    NASA Astrophysics Data System (ADS)

    Nazareth, Daryl P.; Spaans, Jason D.

    2015-05-01

    Optimization methods are critical to radiation therapy. A new technology, quantum annealing (QA), employs novel hardware and software techniques to address various discrete optimization problems in many fields. We report on the first application of quantum annealing to the process of beamlet intensity optimization for IMRT. We apply recently-developed hardware which natively exploits quantum mechanical effects for improved optimization. The new algorithm, called QA, is most similar to simulated annealing, but relies on natural processes to directly minimize a system’s free energy. A simple quantum system is slowly evolved into a classical system representing the objective function. If the evolution is sufficiently slow, there are probabilistic guarantees that a global minimum will be located. To apply QA to IMRT-type optimization, two prostate cases were considered. A reduced number of beamlets were employed, due to the current QA hardware limitations. The beamlet dose matrices were computed using CERR and an objective function was defined based on typical clinical constraints, including dose-volume objectives, which result in a complex non-convex search space. The objective function was discretized and the QA method was compared to two standard optimization methods, simulated annealing and Tabu search, run on a conventional computing cluster. Based on several runs, the average final objective function value achieved by the QA was 16.9 for the first patient, compared with 10.0 for Tabu and 6.7 for the simulated annealing (SA) method. For the second patient, the values were 70.7 for the QA, 120.0 for Tabu and 22.9 for the SA. The QA algorithm required 27-38% of the time required by the other two methods. In this first application of hardware-enabled QA to IMRT optimization, its performance is comparable to Tabu search, but less effective than the SA in terms of final objective function values. However, its speed was 3-4 times faster than the other two methods

  4. First application of quantum annealing to IMRT beamlet intensity optimization.

    PubMed

    Nazareth, Daryl P; Spaans, Jason D

    2015-05-21

    Optimization methods are critical to radiation therapy. A new technology, quantum annealing (QA), employs novel hardware and software techniques to address various discrete optimization problems in many fields. We report on the first application of quantum annealing to the process of beamlet intensity optimization for IMRT. We apply recently-developed hardware which natively exploits quantum mechanical effects for improved optimization. The new algorithm, called QA, is most similar to simulated annealing, but relies on natural processes to directly minimize a system's free energy. A simple quantum system is slowly evolved into a classical system representing the objective function. If the evolution is sufficiently slow, there are probabilistic guarantees that a global minimum will be located. To apply QA to IMRT-type optimization, two prostate cases were considered. A reduced number of beamlets were employed, due to the current QA hardware limitations. The beamlet dose matrices were computed using CERR and an objective function was defined based on typical clinical constraints, including dose-volume objectives, which result in a complex non-convex search space. The objective function was discretized and the QA method was compared to two standard optimization methods, simulated annealing and Tabu search, run on a conventional computing cluster. Based on several runs, the average final objective function value achieved by the QA was 16.9 for the first patient, compared with 10.0 for Tabu and 6.7 for the simulated annealing (SA) method. For the second patient, the values were 70.7 for the QA, 120.0 for Tabu and 22.9 for the SA. The QA algorithm required 27-38% of the time required by the other two methods. In this first application of hardware-enabled QA to IMRT optimization, its performance is comparable to Tabu search, but less effective than the SA in terms of final objective function values. However, its speed was 3-4 times faster than the other two methods. This

  5. Crystal Nucleation in Plasma Deposited Dlc Coatings during Annealing

    NASA Astrophysics Data System (ADS)

    Chaliampalias, D.; Pavlidou, E.; Psyllaki, P.; Chrissafis, K.; Vourlias, G.

    2010-01-01

    Diamond-like carbon (DLC) films, hard carbon coatings, with unique physical and mechanical properties which approach those of natural diamond, such as high hardness, low coefficient of friction and chemical inertness. In several applications, heavy loads and high friction forces are generated and lead to local temperature increase. In such cases these coatings must be thermal stable and with enhanced high temperature oxidation resistance in order to be good candidates for wear protection of metallic components. In the present study a radio frequency plasma deposition system was used for the deposition of 2 μm-thick amorphous DLC coatings onto AISI D2 substrates. The as deposited DLC covered samples were dense, homogeneous and well bonded to the substrate, while no cracks were observed. In order to study the thermal stability of the coatings' DLC nature, in-situ Transmission Electron Microscopic (TEM) observations were carried out during slow annealing of the specimen in the microscope vacuum chamber, as well as thermo-gravimetric (TG) measurements in argon atmosphere, up to 800° C. The first crystallites appeared within the DLC amorphous matrix at about 450° C as surface crystallization, while the mass crystallization started at 600° C as the TG measurements indicated. Finally, the nucleation was completed at 700° C. The oxidation results, performed from ambient temperature up to 1000° C, showed that DLC covered coupons are remarkably resistant as their mass gain was significantly lower than that of the uncovered substrates.

  6. Effect of Interim Annealing on Mechanical Strength of TFA-MOD Derived YBCO Coated Conductors

    NASA Astrophysics Data System (ADS)

    Takagi, Y.; Nakaoka, K.; Nakamura, T.; Yoshizumi, M.; Kiss, T.; Izumi, T.; Shiohara, Y.

    TFA-MOD derived YBCO tapes are expected for many applications due to cost-efficiency. In some applications, uniformity and mechanical strength are required for tapes. A 205 m-long YBCO tape was fabricated with high and uniform Ic performance throughout the tape by adopting the interim annealing before the conversion process. The effect of the interim annealing on the crystal growth mechanism of YBCO has been studied focusing on the relationship between the interim annealing conditions and delamination, in this work. Delamination strength was evaluated in the samples prepared with and without interim annealing by the stud pull method. Measurements were carried out on 50 different points for each sample and the results were analyzed statistically. The difference between the two samples was remarkably seen in the delamination strength below 60 MPa. The conventionally annealed sample had more points with low delamination strength below 60 MPa than the interim annealed one. The cross sectional images of both samples observed by SEM showed that there were few pores within the interim annealed superconducting layer, although conventional superconducting layer had many pores. These results suggest that the pores within YBCO layer might be origins to be propagated for delamination at low strength.

  7. Annealing effect for SnS thin films prepared by high-vacuum evaporation

    SciTech Connect

    Revathi, Naidu Bereznev, Sergei; Loorits, Mihkel; Raudoja, Jaan; Lehner, Julia; Gurevits, Jelena; Traksmaa, Rainer; Mikli, Valdek; Mellikov, Enn; Volobujeva, Olga

    2014-11-01

    Thin films of SnS are deposited onto molybdenum-coated soda lime glass substrates using the high-vacuum evaporation technique at a substrate temperature of 300 °C. The as-deposited SnS layers are then annealed in three different media: (1) H{sub 2}S, (2) argon, and (3) vacuum, for different periods and temperatures to study the changes in the microstructural properties of the layers and to prepare single-phase SnS photoabsorber films. It is found that annealing the layers in H{sub 2}S at 400 °C changes the stoichiometry of the as-deposited SnS films and leads to the formation of a dominant SnS{sub 2} phase. Annealing in an argon atmosphere for 1 h, however, causes no deviations in the composition of the SnS films, though the surface morphology of the annealed SnS layers changes significantly as a result of a 2 h annealing process. The crystalline structure, surface morphology, and photosensitivity of the as-deposited SnS films improves significantly as the result of annealing in vacuum, and the vacuum-annealed films are found to exhibit promising properties for fabricating complete solar cells based on these single-phase SnS photoabsorber layers.

  8. Annealed CVD molybdenum thin film surface

    DOEpatents

    Carver, Gary E.; Seraphin, Bernhard O.

    1984-01-01

    Molybdenum thin films deposited by pyrolytic decomposition of Mo(CO).sub.6 attain, after anneal in a reducing atmosphere at temperatures greater than 700.degree. C., infrared reflectance values greater than reflectance of supersmooth bulk molybdenum. Black molybdenum films deposited under oxidizing conditions and annealed, when covered with an anti-reflecting coating, approach the ideal solar collector characteristic of visible light absorber and infrared energy reflector.

  9. Magnetic induced heating for ferritic metal annealing

    SciTech Connect

    De Witt, G.L.; Huber, D.J.

    1987-03-24

    A method is described for annealing the wall of a nuclear reactor vessel, including, positioning an electromagnet within a vertically positioned nuclear reactor vessel by lowering the electromagnet into the vessel, supplying power to the electromagnet to generate substantially uniform heat in the vessel wall, maintaining the power to the electromagnet for a predetermined length of time which will anneal the vessel wall, and removing the electromagnet.

  10. The optical functions of silicon at elevated temperatures and their application to pulsed laser annealing

    SciTech Connect

    Jellison, G.E. Jr.; Lowndes, D.H.; Wood, R.F.

    1993-06-01

    The results of measurements of the optical functions of silicon at elevated temperatures are reviewed and the results applied to pulsed laser annealing of silicon. Several optical experiments which were performed to understand the physics of pulsed laser annealing are described, and related to detailed thermal modeling. The fabrication of silicon solar cells using both thermal and laser processing is described, both of which give very goods results.

  11. Annealing Texture of Nanostructured Steel-Based Nanocomposite

    NASA Astrophysics Data System (ADS)

    Jamaati, Roohollah

    2015-08-01

    In this research, the evolution of annealing texture in nanostructured steel-based nanocomposite fabricated via accumulative roll bonding (ARB) process was investigated. Textural evolution after post-annealing of ARB-processed samples was evaluated using x-ray diffraction. Average grain size of the sample before and after the post-annealing was 55 nm and 1.5 µm, and the microstructures were uniform. All the samples indicated a strong α-fiber and γ-fiber and a relatively weak ζ-fiber. Also, there were texture transitions in the α-fiber, ɛ-fiber, γ-fiber, η-fiber, and θ-fiber. In addition, for all the samples, the intensities of the rolling textures were higher than those of the shear textures. Moreover, there was a progressive increase in the fraction of high-angle grain boundaries with the increasing strain. Finally, with increasing number of ARB cycles, the intensities of rolling and shear textures changed, and no stable texture was formed.

  12. Error suppression and correction for quantum annealing

    NASA Astrophysics Data System (ADS)

    Lidar, Daniel

    While adiabatic quantum computing and quantum annealing enjoy a certain degree of inherent robustness against excitations and control errors, there is no escaping the need for error correction or suppression. In this talk I will give an overview of our work on the development of such error correction and suppression methods. We have experimentally tested one such method combining encoding, energy penalties and decoding, on a D-Wave Two processor, with encouraging results. Mean field theory shows that this can be explained in terms of a softening of the closing of the gap due to the energy penalty, resulting in protection against excitations that occur near the quantum critical point. Decoding recovers population from excited states and enhances the success probability of quantum annealing. Moreover, we have demonstrated that using repetition codes with increasing code distance can lower the effective temperature of the annealer. References: K.L. Pudenz, T. Albash, D.A. Lidar, ``Error corrected quantum annealing with hundreds of qubits'', Nature Commun. 5, 3243 (2014). K.L. Pudenz, T. Albash, D.A. Lidar, ``Quantum annealing correction for random Ising problems'', Phys. Rev. A. 91, 042302 (2015). S. Matsuura, H. Nishimori, T. Albash, D.A. Lidar, ``Mean Field Analysis of Quantum Annealing Correction''. arXiv:1510.07709. W. Vinci et al., in preparation.

  13. Acquisition speed comparison of microscope software programs.

    PubMed

    Biehlmaier, Oliver; Hehl, Joachim; Csucs, Gabor

    2011-06-01

    Reliable software is a prerequisite for successful operation of a modern wide field fluorescence microscope. When used for live cell imaging, acquisition speed is of particular interest. This is both because biological processes can be highly-dynamic, and to avoid unnecessary photobleaching and phototoxicity of living samples. This article shows that besides the hardware (microscope) components themselves, the acquisition control software is an important influencing factor of speed performance. We tested and compared the speed performance of five different generic applications (Image-Pro Plus, MetaMorph, Micro-Manager, SlideBook, and Volocity) using typical experimental setups involving a single specific state-of-the-art fluorescence microscope configuration. The test measurements included multichannel experiments, z-stacking, burst acquisition, as well as combinations of these measurements with time-lapse acquisitions. The measured data provided values for guiding the testing and analysis of other microscope systems with similar configurations. Despite the identical hardware settings, significant and surprisingly large speed differences were evident among the various software applications. Additionally, no application was identifiable as the fastest in all tests. Our work pinpoints the importance of the control software in determining a system's "real" maximal imaging speed. The study could serve as basis for further tests, eventually influencing the system selection criteria for speed-sensitive applications. PMID:21604324

  14. Carbon nanotube electron sources for electron microscopes

    SciTech Connect

    De Jonge, Niels

    2009-01-01

    Electron sources were made from individual multi-walled carbon nanotubes with closed caps and thoroughly cleaned surfaces. Nanotubes from both chemical vapor deposition growth and arc discharge growth were investigated. These emitters provide a highly stable emission current up to a threshold current of a few microamperes. At too large currents several processes take place such as splitting, breaking and cap closing. The emission process is field emission for a workfunction of 5 eV. The electron optical per-formance is highly beneficial for their use as high-brightness point sources in electron microscopes and advantageous with respect to state-of-the-art electron sources. The life-time is at least two years. We have tested the source successfully in a scanning electron microscope.

  15. Annealing-induced alloy formation in Pd/Fe bilayers on Si(1 1 1) for hydrogen sensing

    NASA Astrophysics Data System (ADS)

    Mudinepalli, Venkata Ramana; Tsai, Cheng-Jui; Chuang, Ying-Chin; Chang, Po-Chun; Plusnin, N.; Lin, Wen-Chin

    2016-03-01

    The bilayers of Pd and Fe with different thickness and relative positions were grown on Si(1 1 1)-7 × 7 surface at room temperature. For the investigation of the thermal annealing induced inter-diffusion and the corresponding magnetic behavior, Auger electron spectroscopy (AES) measurement was carried out after various annealing processes, including the variation of annealing duration and temperature. With the annealing temperature of 300-500 K, the Pd/Fe bilayers were stable. Slight Si segregated into the thin film at around 700 K. Above 700 K, more serious Si segregation occurred and most of the Pd/Fe bilayer was mixed with Si, forming a silicide layer. 700-800 K annealing also induced change of Pd/Fe AES ratio, indicating the inter-diffusion between Pd and Fe layers. To overcome the unavoidable silicide formation induced magnetic dead layer, a relative thick Fe film of 20 ML capped with 1.5 ML Pd was chosen for the investigation of magnetism. The magnetic coercivity (Hc) increased by 2-3 times with the annealing temperature up to 740 K. Obvious hydrogenation effect was observed in 710 K-annealed sample; the in-plane Hc increased by more than 10% when the hydrogen pressure was above 200 mbar. After further annealing at 740-800 K, the hydrogenation effect on Hc became nearly unobservable. The annealing induced Pd-rich magnetic interface is supposed to dominate the hydrogenation effect on magnetism.

  16. Mars Under the Microscope (color)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This magnified look at the martian soil near the Mars Exploration Rover Opportunity's landing site, Meridiani Planum, shows coarse grains sprinkled over a fine layer of sand. The image was captured by the rover's microscopic imager on the 10th day, or sol, of its mission and roughly approximates the color a human eye would see. Scientists are intrigued by the spherical rocks, which can be formed by a variety of geologic processes, including cooling of molten lava droplets and accretion of concentric layers of material around a particle or 'seed.'

    The examined patch of soil is 3 centimeters (1.2 inches) across. The circular grain in the lower left corner is approximately 3 millimeters (.12 inches) across, or about the size of a sunflower seed.

    This color composite was obtained by merging images acquired with the orange-tinted dust cover in both its open and closed positions. The blue tint at the lower right corner is a tag used by scientists to indicate that the dust cover is closed.

  17. Mars Under the Microscope (stretched)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This magnified look at the martian soil near the Mars Exploration Rover Opportunity's landing site, Meridiani Planum, shows coarse grains sprinkled over a fine layer of sand. The image was captured on the 10th day, or sol, of the rover's mission by its microscopic imager, located on the instrument deployment device, or 'arm.' Scientists are intrigued by the spherical rocks, which can be formed by a variety of geologic processes, including cooling of molten lava droplets and accretion of concentric layers of material around a particle or 'seed.'

    The examined patch of soil is 3 centimeters (1.2 inches) across. The circular grain in the lower left corner is approximately 3 millimeters (.12 inches) across, or about the size of a sunflower seed.

    This stretched color composite was obtained by merging images acquired with the orange-tinted dust cover open and closed. The varying hints of orange suggest differences in mineral composition. The blue tint at the lower right corner is a tag used by scientists to indicate that the dust cover is closed.

  18. Problematic microscopic trace (?) fossils, Oligocene, Slovakia

    NASA Astrophysics Data System (ADS)

    Mikuláš, R.; Boorová, D.; Holcová, K.

    2013-05-01

    Meioscopic to microscopic capsules found in reddish, probably marine or brackish shales (Oligocene, Pannonian Basin; South Slovakia) are interpreted as possible trace fossils. They may represent burrows of meioscopic in-fauna. Ferruginous walls of the capsules appeared very probably as late as during diagenesis; however, the (possibly organic) matrix had to exist before the diagenetic processes. Other discussed explanations (inorganic "ironstones"; coprolites) are not plausible.

  19. Microscopic and Macroscopic Studies on Resistance Responses to Daylily Rust

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Infection process of Puccinia hemerocallidis, the causal agent of daylily rust, and resistance responses in eight daylily cultivars were studied macroscopically and microscopically. After germination of urediniospores, appressoria formed at the tip of germ tubes and penetrated through stomatal openi...

  20. Laser annealing and simulation of amorphous silicon thin films for solar cell applications

    NASA Astrophysics Data System (ADS)

    Theodorakos, I.; Raptis, Y. S.; Vamvakas, V.; Tsoukalas, D.; Zergioti, I.

    2014-03-01

    In this work, a picosecond DPSS and a nanosecond Nd:YAG laser have been used for the annealing and the partial nanocrystallization of an amorphous silicon layer. These experiments were conducted in order to improve the characteristics of a micromorph tandem solar cell. The laser annealing was attempted at 1064nm in order to obtain the desired crystallization's depth and ratios. Preliminary annealing-processes, with different annealing parameters, have been tested, such as fluence, repetition rate and number of pulses. Irradiations were applied in the sub-melt regime, in order to prevent significant diffusion of p- and n-dopants to take place within the structure. The laser experimental work was combined with simulations of the laser annealing process, in terms of temperature distribution evolution, using the Synopsys Sentaurus Process TCAD software. The optimum annealing conditions for the two different pulse durations were determined. Experimentally determined optical properties of our samples, such as the absorption coefficient and reflectivity, were used for a more realistic simulation. From the simulations results, a temperature profile, appropriate to yield the desired recrystallization was obtained for the case of ps pulses, which was verified from the experimental results described below. The annealed material was studied, as far as it concerns its structural properties, by XRD, SEM and micro-Raman techniques, providing consistent information on the characteristics of the nanocrystalline material produced by the laser annealing experiments. It was found that, with the use of ps pulses, the resultant polycrystalline region shows crystallization's ratios similar to a PECVD developed poly-Silicon layer, with slightly larger nanocrystallite's size.

  1. Enhanced annealing of GaAs solar cell radiation damage

    NASA Technical Reports Server (NTRS)

    Loo, R.; Knechtli, R. C.; Kamath, G. S.

    1981-01-01

    Solar cells are degraded by radiation damage in space. Investigations have been conducted concerning possibilities for annealing this radiation damage in GaAs solar cells, taking into account the conditions favoring such annealing. It has been found that continuous annealing as well as the combination of injection annealing with thermal annealing can lead to recovery from radiation damage under particularly favorable conditions in GaAs solar cells. The damage caused by both electrons and protons in GaAs solar cells can be substantially reduced by annealing at temperatures as low as 150 C, under appropriate conditions. This possibility makes the GaAs solar cells especially attractive for long space missions, or for missions in severe radiation environments. Attention is given to results concerning periodic thermal annealing, continuous annealing, and injection annealing combined with thermal annealing.

  2. A microscopic field theoretical approach for active systems

    NASA Astrophysics Data System (ADS)

    Alaimo, F.; Praetorius, S.; Voigt, A.

    2016-08-01

    We consider a microscopic modeling approach for active systems. The approach extends the phase field crystal (PFC) model and allows us to describe generic properties of active systems within a continuum model. The approach is validated by reproducing results obtained with corresponding agent-based and microscopic phase field models. We consider binary collisions, collective motion and vortex formation. For larger numbers of particles we analyze the coarsening process in active crystals and identify giant number fluctuation in a cluster formation process.

  3. (Center of excellence: Microlaser microscope)

    SciTech Connect

    Webb, R.H.

    1992-01-01

    This Center-of-Excellence grant has two components: development of an imaging system based on microlaser arrays forms a central project among a group of laser diagnostic and therapeutic efforts primarily funded outside the grant. In these first 8 months we have set up the Microlaser Microscope using small microlaser arrays. We have emphasized the basics of microlaser handling and electronic addressing and the optics of the microscope. Details of electronics and optics given here will be used in the larger arrays which should be available soon. After a description of the central Microlaser Microscope project, we touch briefly on the other projects of the Center, which have been outstandingly fruitful this year. Publications are necessarily concerned with the smaller projects, since the Microlaser Microscope is in its early stages.

  4. Center of excellence: Microlaser microscope

    NASA Astrophysics Data System (ADS)

    Webb, R. H.

    This Center-of-Excellence grant has two components: development of an imaging system based on microlaser arrays forms a central project among a group of laser diagnostic and therapeutic efforts primarily funded outside the grant. In these first 8 months we have set up the Microlaser Microscope using small microlaser arrays. We have emphasized the basics of microlaser handling and electronic addressing and the optics of the microscope. Details of electronics and optics given here will be used in the larger arrays which should be available soon. After a description of the central Microlaser Microscope project, we touch briefly on the other projects of the Center, which have been outstandingly fruitful this year. Publications are necessarily concerned with the smaller projects, since the Microlaser Microscope is in its early stages.

  5. Mars Life? - Microscopic Tubular Structures

    NASA Technical Reports Server (NTRS)

    1996-01-01

    This electron microscope image shows extremely tiny tubular structures that are possible microscopic fossils of bacteria-like organisms that may have lived on Mars more than 3.6 billion years ago. A two-year investigation by a NASA research team found organic molecules, mineral features characteristic of biological activity and possible microscopic fossils such as these inside of an ancient Martian rock that fell to Earth as a meteorite. The largest possible fossils are less than 1/100th the diameter of a human hair in size while most are ten times smaller. The fossil-like structures were found in carbonate minerals formed along pre-existing fractures in the meteorite in a fashion similar to the way fossils occur in limestone on Earth, although on a microscopic scale.

  6. Microscopic Procedures for Plant Meiosis.

    ERIC Educational Resources Information Center

    Braselton, James P.

    1997-01-01

    Describes laboratory techniques designed to familiarize students with meiosis and how microscopic preparations of meiosis are made. These techniques require the use of fresh or fixed flowers. Contains 18 references. (DDR)

  7. Adirondack Under the Microscope-2

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This overhead look at the martian rock dubbed Adirondack was captured by the Mars Exploration Rover Spirit's panoramic camera. It shows the approximate region where the rover's microscopic imager began its first close-up inspection.

  8. Microscopic derivation of discrete hydrodynamics.

    PubMed

    Español, Pep; Anero, Jesús G; Zúñiga, Ignacio

    2009-12-28

    By using the standard theory of coarse graining based on Zwanzig's projection operator, we derive the dynamic equations for discrete hydrodynamic variables. These hydrodynamic variables are defined in terms of the Delaunay triangulation. The resulting microscopically derived equations can be understood, a posteriori, as a discretization on an arbitrary irregular grid of the Navier-Stokes equations. The microscopic derivation provides a set of discrete equations that exactly conserves mass, momentum, and energy and the dissipative part of the dynamics produces strict entropy increase. In addition, the microscopic derivation provides a practical implementation of thermal fluctuations in a way that the fluctuation-dissipation theorem is satisfied exactly. This paper points toward a close connection between coarse-graining procedures from microscopic dynamics and discretization schemes for partial differential equations. PMID:20059064

  9. HIGH TEMPERATURE MICROSCOPE AND FURNACE

    DOEpatents

    Olson, D.M.

    1961-01-31

    A high-temperature microscope is offered. It has a reflecting optic situated above a molten specimen in a furnace and reflecting the image of the same downward through an inert optic member in the floor of the furnace, a plurality of spaced reflecting plane mirrors defining a reflecting path around the furnace, a standard microscope supported in the path of and forming the end terminus of the light path.

  10. Laser annealed composite titanium dioxide electrodes for dye-sensitized solar cells on glass and plastics

    NASA Astrophysics Data System (ADS)

    Pan, Heng; Ko, Seung Hwan; Misra, Nipun; Grigoropoulos, Costas P.

    2009-02-01

    We report a rapid and low temperature process for fabricating composite TiO2 electrodes for dye-sensitized solar cells on glass and plastics by in tandem spray deposition and laser annealing. A homogenized KrF excimer laser beam (248 nm) was used to layer-by-layer anneal spray deposited TiO2 nanoparticles. The produced TiO2 film is crack free and contains small particles (30 nm) mixed with different fractions of larger particles (100-200 nm) controlled by the applied laser fluence. Laser annealed double-layered structure is demonstrated for both doctor-blade deposited and spray-deposited electrodes and performance enhancement can be observed. The highest demonstrated all-laser-annealed cells utilizing ruthenium dye and liquid electrolyte showed power conversion efficiency of ˜3.8% under simulated illumination of 100 mW/cm2.

  11. A Way of Tailoring Magnetic Anisotropy of Co Nanowire Arrays: Magnetic Field Annealing.

    PubMed

    Ren, Yong; Qu, Li; Fan, Jiangxia; Dai, Bo; Wang, Jianbo

    2015-06-01

    Hexagonal close-packed Co nanowire arrays in anodic aluminum oxide template with the diameter of 50 nm have been fabricated using an ac electrodeposition method. The effect of magnetic field annealing on the thermal stability and magnetic properties of these nanwire arrays was studied. XRD measurements indicate the increase of diffraction intensity with the increase of heat-treatment temperature without magnetic field. Furthermore, the intensity of diffraction peak decreases rapidly if the sample undergoes the magnetic field annealing. Influence of different annealing process on the magnetic properties of Co nanowire arrays has also been studied. It is found that the magnetocrystalline anisotropy of hcp Co becomes weaker after magnetic field annealing, which lead to increase of the total anisotropy of Co nanowire arrays. PMID:26369071

  12. Noble-metal Ag nanoparticle chains: annealing Ag/Bi superlattice nanowires in vacuum

    NASA Astrophysics Data System (ADS)

    Xu, Shao Hui; Fei, Guang Tao; You, Qiao; Gao, Xu Dong; Huo, Peng Cheng; De Zhang, Li

    2016-09-01

    One-dimensional noble-metal Ag nanoparticle chains have been prepared by electrodepositing Ag/Bi superlattice nanowires in a porous anodic alumina oxide (AAO) template and following an annealing process in vacuum. It is found that Bi, as a sacrificial metal, can be removed completely after annealing at 450 °C with a vacuum degree of 10‑5 Torr. The regulation of particle size, shape and interparticle spacing of Ag NP chains has been realized by adjusting the segment length of the Ag/Bi superlattice nanowires and the annealing condition. With an extension of the annealing time, it is observed that Ag particles display the transform trend from ellipsoid to sphere. Our findings could inspire further investigation on the design and fabrication of metal nanoparticle chains.

  13. Production of high-quality ZnO films by the two-step annealing method

    NASA Astrophysics Data System (ADS)

    Ye, J. D.; Gu, S. L.; Zhu, S. M.; Qin, F.; Liu, S. M.; Liu, W.; Zhou, X.; Hu, L. Q.; Zhang, R.; Shi, Y.; Zheng, Y. D.

    2004-11-01

    In this study, a two-step annealing method is advanced to produce high-quality ZnO films with excellent structural, electrical, and optical properties. The effects of oxygen and nitrogen annealing on the properties of undoped ZnO films are reversible to each other and are attributed to the creation and annihilation of extrinsic trap states of antisite oxygen OZn and oxygen vacancies VO, which result from the chemisorption and desorption of oxygen, respectively. Moreover, annealing in nitrogen causes slight nitrogen incorporation, subsequently increasing the resistivity and inducing compressive stress in the film. The key to this two-step method is to keep the chemisorption and desorption of oxygen in equilibrium. Due to the similarity of annealing ambient with the growth condition, this process can be transplanted and employed in the in situ preparation of high-quality ZnO epilayers.

  14. Noble-metal Ag nanoparticle chains: annealing Ag/Bi superlattice nanowires in vacuum.

    PubMed

    Xu, Shao Hui; Fei, Guang Tao; You, Qiao; Gao, Xu Dong; Huo, Peng Cheng; De Zhang, Li

    2016-09-16

    One-dimensional noble-metal Ag nanoparticle chains have been prepared by electrodepositing Ag/Bi superlattice nanowires in a porous anodic alumina oxide (AAO) template and following an annealing process in vacuum. It is found that Bi, as a sacrificial metal, can be removed completely after annealing at 450 °C with a vacuum degree of 10(-5) Torr. The regulation of particle size, shape and interparticle spacing of Ag NP chains has been realized by adjusting the segment length of the Ag/Bi superlattice nanowires and the annealing condition. With an extension of the annealing time, it is observed that Ag particles display the transform trend from ellipsoid to sphere. Our findings could inspire further investigation on the design and fabrication of metal nanoparticle chains. PMID:27487089

  15. Laser Annealing to Form High-Temperature Phase of FeS2

    NASA Astrophysics Data System (ADS)

    Umehara, Mitsutaro; Takeda, Yasuhiko; Azuma, Hirozumi; Motohiro, Tomoyoshi

    2012-02-01

    We fabricated single-phase pyrite thin films of FeS2 by laser annealing of multi-phase FeS2 films. Sputter-deposited FeS films followed by sulfurization in sulfur vapor at high temperatures were mainly composed of the high-temperature phase (pyrite) but contained a small amount of the low-temperature phase (marcasite) that likely grew when the samples were naturally cooled after the sulfurization. We applied the rapid cooling feature of laser annealing to preventing the marcasite phase formation. No trace of marcasite phase was observed in Raman spectra and X-ray diffraction patterns of the laser-annealed samples. We analyzed temporal evolution of the sample temperature during the laser-annealing processes to confirm that the laser heating induced phase change of the small amount of marcasite to pyrite and the rapid cooling prevented marcasite regrowth.

  16. Growth of Ni2Si by rapid thermal annealing: Kinetics and moving species

    NASA Astrophysics Data System (ADS)

    Ma, E.; Lim, B. S.; Nicolet, M.-A.; Natan, M.

    1987-10-01

    The growth kinetics is characterized and the moving species is identified for the formation of Ni2Si by Rapid Thermal Annealing (RTA) of sequentially deposited Si and Ni films on a <100> Si substrate. The interfacial Ni2Si layer grows as the square root of time, indicating that the suicide growth process is diffusion-limited. The activation energy is 1.25±0.2 eV in the RTA temperature range of 350 450° C. The results extend those of conventional steady-state furnace annealing quite fittingly, and a common activation energy of 1.3±0.2 eV is deduced from 225° to 450° C. The marker experiment shows that Ni is the dominant moving species during Ni2Si formation by RTA, as is the case for furnace annealing. It is concluded that the two annealing techniques induce the same growth mechanisms in Ni2Si formation.

  17. Origin of reverse annealing effect in hydrogen-implanted silicon

    SciTech Connect

    Di, Zengfeng; Nastasi, Michael A; Wang, Yongqiang

    2009-01-01

    In contradiction to conventional damage annealing, thermally annealed H-implanted Si exhibits an increase in damage or reverse annealing behavior, whose mechanism has remained elusive. On the basis of quantitative high resolution transmission electron microscopy combined with channeling Rutherford backscattering analysis, we conclusively elucidate that the reverse annealing effect is due to the nucleation and growth of hydrogen-induce platelets. Platelets are responsible for an increase in the height and width the channeling damage peak following increased isochronal anneals.

  18. Origin of reverse annealing effect in hydrogen-implanted silicon

    SciTech Connect

    Di, Z. F.; Wang, Y. Q.; Nastasi, M.; Theodore, N. David

    2010-04-12

    In contradiction to conventional damage annealing, thermally annealed H-implanted Si exhibits an increase in damage or reverse annealing behavior, whose mechanism has remained elusive. In this work, we conclusively elucidate that the reverse annealing effect is due to the nucleation and growth of hydrogen-induced platelets. Platelets are responsible for an increase in the height and width of the channeling damage peak following increased isochronal anneals.

  19. Compact Microscope Imaging System With Intelligent Controls Improved

    NASA Technical Reports Server (NTRS)

    McDowell, Mark

    2004-01-01

    The Compact Microscope Imaging System (CMIS) with intelligent controls is a diagnostic microscope analysis tool with intelligent controls for use in space, industrial, medical, and security applications. This compact miniature microscope, which can perform tasks usually reserved for conventional microscopes, has unique advantages in the fields of microscopy, biomedical research, inline process inspection, and space science. Its unique approach integrates a machine vision technique with an instrumentation and control technique that provides intelligence via the use of adaptive neural networks. The CMIS system was developed at the NASA Glenn Research Center specifically for interface detection used for colloid hard spheres experiments; biological cell detection for patch clamping, cell movement, and tracking; and detection of anode and cathode defects for laboratory samples using microscope technology.

  20. Dynamical SCFT Simulations of Solvent Annealed Thin Films

    NASA Astrophysics Data System (ADS)

    Paradiso, Sean; Delaney, Kris; Ceniceros, Hector; Garcia-Cervera, Carlos; Fredrickson, Glenn

    2014-03-01

    Block copolymer thin films are ideal candidates for a broad range of technologies including rejection layers for ultrafiltration membranes, proton-exchange membranes in solar cells, optically active coatings, and lithographic masks for bit patterning storage media. Optimizing the performance of these materials often hinges on tuning the orientation and long-range order of the film's internal nanostructure. In response, solvent annealing techniques have been developed for their promise to afford additional flexibility in tuning thin film morphology, but pronounced processing history dependence and a dizzying parameter space have resulted in slow progress towards developing clear design rules for solvent annealing systems. In this talk, we will report recent theoretical progress in understanding the self assembly dynamics relevant to solvent-annealed and solution-cast block copolymer films. Emphasis will be placed on evaporation-induced ordering trends in both the slow and fast drying regimes for cylinder-forming block copolymers from initially ordered and disordered films, along with the role solvent selectivity plays in the ordering dynamics.

  1. Thin tungsten telluride layer preparation by thermal annealing.

    PubMed

    Lu, Wei; Zhang, Yudao; Zhu, Zusong; Lai, Jiawei; Zhao, Chuan; Liu, Xuefeng; Liu, Jing; Sun, Dong

    2016-10-14

    We report a simple method to prepare a thin Tungsten Telluride (WTe2) flake with accurate thickness control, which allows preparing and studying this two dimensional material conveniently. First, the WTe2 flake, which is relatively thick due to its strong interlayer van der Waals forces, is obtained by a conventional mechanical exfoliation method. Then, the exfoliated flake is annealed at 600 °C under a constant Ar protecting flow. Raman and atomic force spectroscopy characterizations demonstrate that thermal annealing can effectively thin down the WTe2 flake and retain its original lattice structure, though its surface smoothness is slightly deteriorated. Additionally, systematical study indicates that the thinning process strongly depends on the initial thickness of the WTe2 flake before annealing: the thinning rate increases from 0.12 nm min(-1) to 0.36 nm min(-1) as the initial thickness increases from 10 nm to 45 nm, while the roughness of the final product also increases with the increase of its initial thickness. However, the method fails when it is applied to WTe2 flakes thicker than 100 nm, resulting in uneven or burnt surface, which is possibly caused by big cavities formed by a large amount of defects gathered at the top surface. PMID:27608057

  2. Maximum-Entropy Inference with a Programmable Annealer

    PubMed Central

    Chancellor, Nicholas; Szoke, Szilard; Vinci, Walter; Aeppli, Gabriel; Warburton, Paul A.

    2016-01-01

    Optimisation problems typically involve finding the ground state (i.e. the minimum energy configuration) of a cost function with respect to many variables. If the variables are corrupted by noise then this maximises the likelihood that the solution is correct. The maximum entropy solution on the other hand takes the form of a Boltzmann distribution over the ground and excited states of the cost function to correct for noise. Here we use a programmable annealer for the information decoding problem which we simulate as a random Ising model in a field. We show experimentally that finite temperature maximum entropy decoding can give slightly better bit-error-rates than the maximum likelihood approach, confirming that useful information can be extracted from the excited states of the annealer. Furthermore we introduce a bit-by-bit analytical method which is agnostic to the specific application and use it to show that the annealer samples from a highly Boltzmann-like distribution. Machines of this kind are therefore candidates for use in a variety of machine learning applications which exploit maximum entropy inference, including language processing and image recognition. PMID:26936311

  3. Annealing of Silicate Dust by Nebular Shocks at 10 AU

    NASA Technical Reports Server (NTRS)

    Harker, David E.; Desch, Steven J.; DeVincenzi, D. (Technical Monitor)

    2001-01-01

    Silicate dust grains in the interstellar medium are known to be mostly amorphous, yet crystalline silicate grains have been observed in many long-period comets and in protoplanetary disks. Annealing of amorphous silicate grains into crystalline grains requires temperatures greater than or approximately equal to 1000 K, but exposure of dust grains in comets to such high temperatures is apparently incompatible with the generally low temperatures experienced by comets. This has led to the proposal of models in which dust grains were thermally processed near the protoSun, then underwent considerable radial transport until they reached the gas giant planet region where the long-period comets originated. We hypothesize instead that silicate dust grains were annealed in situ, by shock waves triggered by gravitational instabilities. We assume a shock speed of 5 km/s, a plausible value for shocks driven by gravitational instabilities. We calculate the peak temperatures of pyroxene grains under conditions typical in protoplanetary disks at 5-10 AU. We show that in situ annealing of micron-sized dust grains can occur, obviating the need for large-scale radial transport.

  4. Maximum-Entropy Inference with a Programmable Annealer

    NASA Astrophysics Data System (ADS)

    Chancellor, Nicholas; Szoke, Szilard; Vinci, Walter; Aeppli, Gabriel; Warburton, Paul A.

    2016-03-01

    Optimisation problems typically involve finding the ground state (i.e. the minimum energy configuration) of a cost function with respect to many variables. If the variables are corrupted by noise then this maximises the likelihood that the solution is correct. The maximum entropy solution on the other hand takes the form of a Boltzmann distribution over the ground and excited states of the cost function to correct for noise. Here we use a programmable annealer for the information decoding problem which we simulate as a random Ising model in a field. We show experimentally that finite temperature maximum entropy decoding can give slightly better bit-error-rates than the maximum likelihood approach, confirming that useful information can be extracted from the excited states of the annealer. Furthermore we introduce a bit-by-bit analytical method which is agnostic to the specific application and use it to show that the annealer samples from a highly Boltzmann-like distribution. Machines of this kind are therefore candidates for use in a variety of machine learning applications which exploit maximum entropy inference, including language processing and image recognition.

  5. The effect of polyethylene glycol on the stability of pores in polyvinyl alcohol hydrogels during annealing.

    PubMed

    Bodugoz-Senturk, Hatice; Choi, Jeeyoung; Oral, Ebru; Kung, Jean H; Macias, Celia E; Braithwaite, Gavin; Muratoglu, Orhun K

    2008-01-01

    Poly(vinyl alcohol) (PVA) hydrogels are candidate biomaterials for cartilage resurfacing or interpositional arthroplasty devices requiring high-creep resistance and high water content to maintain lubricity. Annealing of PVA improves creep resistance but also reduces the water content. We hypothesized that maintaining poly(ethylene glycol) (PEG) within PVA during annealing would prevent the collapse of the pores and thus would result in high equilibrium water content (EWC). Our hypothesis tested positive. The PVA hydrogels containing PEG maintained their opacity through annealing and exhibited large pores under confocal imaging while hydrogels not containing PEG turned translucent and no pores were visible after annealing. The EWC of gels annealed with PEG (83 +/- 1.0%) was higher than that of the gels processed without PEG (55 +/- 4.8). The crystallinity of the former was 8.0 +/- 1.7% and the latter was 27.5 +/- 8.7%. The hydrogels processed in the presence of PEG exhibited a significantly higher total creep strain (69 +/- 3.4%) when compared to the PEG-free hydrogels (17 +/- 3.7) under an initial contact stress of 0.45 MPa. EWC appeared to be strongly related to the creep resistance of annealed PVA theta-gels. PMID:17950839

  6. Morphology Development in Block Copolymer Thin Films via Direct Immersion Annealing

    NASA Astrophysics Data System (ADS)

    Modi, Arvind; Bhaway, Sarang; Vogt, Bryan; Sharma, Ashutosh; Karim, Alamgir

    2015-03-01

    Conventional methods of annealing thin block copolymer (BCP) films include Thermal Annealing and Solvent Vapor Annealing (SVA) processes. Both of the processes have demonstrated excellent control over morphologies and nanostructures. However, both have constraints including long annealing time duration and/or complicated setup requirement. We introduce Direct Immersion Annealing (DIA) of thin block copolymer (BCP) films involving immersion of polymer films directly into the solvent mixture composed of selective non-solvent and solvent for blocks. Non-solvent prevents the dissolution of films while the good solvent permeates the film and plasticizes the blocks. A fine control of swelling ratio can be achieved through an easy and robust control of solvent volume fractions. We studied cylindrical Poly(styrene-block-methyl methacrylate) system in detail and quantified the growth of correlation length (ξ) with time(t) [ ξ = Atn]. We observe a reduction in growth exponent (n) with several fold increase in pre-exponential factor (A) compared to isotropic thermal annealing. We further demonstrate the extension of this strategy to systems with diverse range of χ-parameter, molecular weight and other morphologies.

  7. Simulation of the post-implantation anneal for emitter profile optimization in high efficiency c-Si solar cells

    NASA Astrophysics Data System (ADS)

    Florakis, A.; Vandervorst, W.; Janssens, T.; Rosseel, E.; Douhard, B.; Delmotte, J.; Cornagliotti, E.; Baert, K.; Posthuma, N.; Poortmans, J.

    2012-11-01

    The use of ion implantation to form local doping profiles in solar cells has regained interest, as it simplifies the manufacturing process, is litho-free, and high efficiency levels can be obtained [1]. However, residual damage after post annealing can lead to increased saturation current values (J0e), so optimization of the annealing process is required. A full simulation of the anneal treatment and its impact on profile and oxide formation was developed, based on the Synopsys Process TCAD software, for the boron doping case. The validity of the models and parameter set was experimentally verified through SIMS (Secondary Ion Mass Spectroscopy) profiles, sheet resistance and ellipsometry measurements.

  8. Thermal annealing of laser damage precursors on fused silica surfaces

    SciTech Connect

    Shen, N; Miller, P E; Bude, J D; Laurence, T A; Suratwala, T I; Steele, W A; Feit, M D; Wang, L L

    2012-03-19

    Previous studies have identified two significant precursors of laser damage on fused silica surfaces at fluenes below {approx} 35 J/cm{sup 2}, photoactive impurities in the polishing layer and surface fractures. In the present work, isothermal heating is studied as a means of remediating the highly absorptive, defect structure associated with surface fractures. A series of Vickers indentations were applied to silica surfaces at loads between 0.5N and 10N creating fracture networks between {approx} 10{micro}m and {approx} 50{micro}m in diameter. The indentations were characterized prior to and following thermal annealing under various times and temperature conditions using confocal time-resolved photo-luminescence (CTP) imaging, and R/1 optical damage testing with 3ns, 355nm laser pulses. Significant improvements in the damage thresholds, together with corresponding reductions in CTP intensity, were observed at temperatures well below the glass transition temperature (T{sub g}). For example, the damage threshold on 05.N indentations which typically initiates at fluences <8 J/cm{sup 2} could be improved >35 J/cm{sup 2} through the use of a {approx} 750 C thermal treatment. Larger fracture networks required longer or higher temperature treatment to achieve similar results. At an annealing temperature > 1100 C, optical microscopy indicates morphological changes in some of the fracture structure of indentations, although remnants of the original fracture and significant deformation was still observed after thermal annealing. This study demonstrates the potential of using isothermal annealing as a means of improving the laser damage resistance of fused silica optical components. Similarly, it provides a means of further understanding the physics associated with optical damage and related mitigation processes.

  9. Rapid annealing using the water-wall arc lamp

    NASA Astrophysics Data System (ADS)

    Gelpey, Jeffrey C.; Stump, Paul O.

    1985-01-01

    Rapid annealing techniques using graphite strip heaters [1], tungsten-halogen lamps [2], and conventional arc lamps [3] have been gaining favor to provide controllable activation of ion implants while minimizing the diffusion of the implanted dopant. These conventional heat sources have given good results, but they all suffer from limitations in power output and/or the ability to change power levels rapidly. The water-wall d.c. arc lamp overcomes these limitations and allows precise control and excellent reproducability of the anneal cycle. The high power output and excellent optical coupling of the water-wall lamp allows ilumination from one side of the sample. The wafer temperature can then be directly monitored with a pyrometer and the fast response time of the lamp allows the pyrometer output to control the lamp power and, hence, provide direct feedback control of the wafer temperature. Direct control is important to overcome variations caused by different doping levels or dielectric coatings on the wafers. Annealing experiments using the water-wall lamp have shown that good activation and essentially complete removal of implant damage can be achieved while moving the junction only minimally [4,5]. The degree of dopant diffusion (generally on the order of 1000 Å) is small compared to device dimensions but is somewhat more than would be expected from classical diffusion theory using published diffusion coefficients. The differences depend on the implanted species and models are being developed to explain the discrepancies. The vary rapid heating and cooling rates obtainable with the water-wall lamp offer a great deal of flexibility in the time/temperature cycles used for annealing (or other rapid thermal processes). There are indications that the ability to achieve a rapid cooling rate allows more complete activation of high dose implants and rapid heating rates may reduce the residual damage and amount of diffusion.

  10. Annealing of ion implanted gallium nitride

    SciTech Connect

    Tan, H.H.; Williams, J.S.; Zou, J.; Cockayne, D.J.; Pearton, S.J.; Zolper, J.C.; Stall, R.A.

    1998-03-01

    In this paper, we examine Si and Te ion implant damage removal in GaN as a function of implantation dose, and implantation and annealing temperature. Transmission electron microscopy shows that amorphous layers, which can result from high-dose implantation, recrystallize between 800 and 1100{degree}C to very defective polycrystalline material. Lower-dose implants (down to 5{times}10{sup 13}cm{sup {minus}2}), which are not amorphous but defective after implantation, also anneal poorly up to 1100{degree}C, leaving a coarse network of extended defects. Despite such disorder, a high fraction of Te is found to be substitutional in GaN both following implantation and after annealing. Furthermore, although elevated-temperature implants result in less disorder after implantation, this damage is also impossible to anneal out completely by 1100{degree}C. The implications of this study are that considerably higher annealing temperatures will be needed to remove damage for optimum electrical properties. {copyright} {ital 1998 American Institute of Physics.}

  11. The annealing robust backpropagation (ARBP) learning algorithm.

    PubMed

    Chuang, C C; Su, S F; Hsiao, C C

    2000-01-01

    Multilayer feedforward neural networks are often referred to as universal approximators. Nevertheless, if the used training data are corrupted by large noise, such as outliers, traditional backpropagation learning schemes may not always come up with acceptable performance. Even though various robust learning algorithms have been proposed in the literature, those approaches still suffer from the initialization problem. In those robust learning algorithms, the so-called M-estimator is employed. For the M-estimation type of learning algorithms, the loss function is used to play the role in discriminating against outliers from the majority by degrading the effects of those outliers in learning. However, the loss function used in those algorithms may not correctly discriminate against those outliers. In this paper, the annealing robust backpropagation learning algorithm (ARBP) that adopts the annealing concept into the robust learning algorithms is proposed to deal with the problem of modeling under the existence of outliers. The proposed algorithm has been employed in various examples. Those results all demonstrated the superiority over other robust learning algorithms independent of outliers. In the paper, not only is the annealing concept adopted into the robust learning algorithms but also the annealing schedule k/t was found experimentally to achieve the best performance among other annealing schedules, where k is a constant and is the epoch number. PMID:18249835

  12. Scanning Miniature Microscopes without Lenses

    NASA Technical Reports Server (NTRS)

    Wang, Yu

    2009-01-01

    The figure schematically depicts some alternative designs of proposed compact, lightweight optoelectronic microscopes that would contain no lenses and would generate magnified video images of specimens. Microscopes of this type were described previously in Miniature Microscope Without Lenses (NPO - 20218), NASA Tech Briefs, Vol. 22, No. 8 (August 1998), page 43 and Reflective Variants of Miniature Microscope Without Lenses (NPO 20610), NASA Tech Briefs, Vol. 26, No. 9 (September 1999), page 6a. To recapitulate: In the design and construction of a microscope of this type, the focusing optics of a conventional microscope are replaced by a combination of a microchannel filter and a charge-coupled-device (CCD) image detector. Elimination of focusing optics reduces the size and weight of the instrument and eliminates the need for the time-consuming focusing operation. The microscopes described in the cited prior articles contained two-dimensional CCDs registered with two-dimensional arrays of microchannels and, as such, were designed to produce full two-dimensional images, without need for scanning. The microscopes of the present proposal would contain one-dimensional (line image) CCDs registered with linear arrays of microchannels. In the operation of such a microscope, one would scan a specimen along a line perpendicular to the array axis (in other words, one would scan in pushbroom fashion). One could then synthesize a full two-dimensional image of the specimen from the line-image data acquired at one-pixel increments of position along the scan. In one of the proposed microscopes, a beam of unpolarized light for illuminating the specimen would enter from the side. This light would be reflected down onto the specimen by a nonpolarizing beam splitter attached to the microchannels at their lower ends. A portion of the light incident on the specimen would be reflected upward, through the beam splitter and along the microchannels, to form an image on the CCD. If the

  13. Influence of crystallite size and surface morphology on electrochemical properties of annealed TiO2 nanotubes

    NASA Astrophysics Data System (ADS)

    Munirathinam, Balakrishnan; Pydimukkala, Haveela; Ramaswamy, Narayanan; Neelakantan, Lakshman

    2015-11-01

    The current study investigates the effect of crystallite size and surface morphology of TiO2 nanotubes on their wettability and electrochemical properties. Self-organized amorphous TiO2 nanotubes were synthesized by anodization process in an acidic (0.5 wt% HF) and a neutral electrolyte (1 M Na2SO4 + 0.5 wt% NaF). Subsequently, the nanotubes were annealed at 450 °C to achieve crystalline phase. Scanning electron microscope micrographs revealed that nanotubes formed from the neutral bath are four times longer (1.2 μm) than the ones synthesized from the acidic bath (325 nm). The charge consumed during anodization is greater under the acidic conditions implying the severity of the attack on the nanotubes by the electrolyte. X-Ray diffraction analysis showed that after annealing TiO2 crystallizes in the tetragonal lattice as anatase structure. Peak fitting method for line profile analysis was employed to estimate the crystallite size and the micro strain. The oxide nanotubes formed in neutral medium showed smaller crystallite size (28.91 nm) than the one formed in acidic medium (43.37 nm). Wettability measurements showed wetting angles <60°, indicating hydrophilic nature of the anatase nanotubes. Further, both the dimensional aspect (i.e., length and diameter of nanotubes) and the crystallite size have significant effect on the hydrophilic behavior. Electrochemical impedance spectroscopy in a simulated body fluid environment confirmed that structural changes in the oxide layer influence the electrochemical properties. Polarization studies demonstrated that crystallite size affects the passive behavior of the nanotubes. Smaller crystallite size (28.91 nm) lowers the passive current density (0.11 μA cm-2), indicating the good protectiveness.

  14. Electrochemical capacitance of iron oxide nanotube (Fe-NT): effect of annealing atmospheres

    NASA Astrophysics Data System (ADS)

    Sarma, Biplab; Jurovitzki, Abraham L.; Ray, Rupashree S.; Smith, York R.; Mohanty, Swomitra K.; Misra, Mano

    2015-07-01

    The effect of annealing atmosphere on the supercapacitance behavior of iron oxide nanotube (Fe-NT) electrodes has been explored and reported here. Iron oxide nanotubes were synthesized on a pure iron substrate through an electrochemical anodization process in an ethylene glycol solution containing 3% H2O and 0.5 wt.% NH4F. Subsequently, the annealing of the nanotubes was carried out at 500 °C for 2 h in various gas atmospheres such as air, oxygen (O2), nitrogen (N2), and argon (Ar). The morphology and crystal phases evolved after the annealing processes were examined via field emission scanning electron microscopy, x-ray diffraction, Raman spectroscopy, and x-ray photoelectron spectroscopy. The electrochemical capacitance properties of the annealed Fe-NT electrodes were evaluated by conducting cyclic voltammetry (CV), galvanostatic charge-discharge, and electrochemical impedance spectroscopy tests in the Li2SO4 electrolyte. Based on these experiments, it was found that the capacitance of the Fe-NT electrodes annealed in air and O2 atmospheres shows mixed behavior comprising both the electric double layer and pseudocapacitance. However, annealing in N2 and Ar environments resulted in well-defined redox peaks in the CV profiles of the Fe-NT electrodes, which are therefore attributed to the relatively higher pseudonature of the capacitance in these electrodes. Based on the galvanostatic charge-discharge studies, the specific capacitance achieved in the Fe-NT electrode after annealing in Ar was about 300 mF cm-2, which was about twice the value obtained for N2-annealed Fe-NTs and three times higher than those annealed in air and O2. The experiments also demonstrated excellent cycle stability for the Fe-NT electrodes with 83%-85% capacitance retention, even after many charge-discharge cycles, irrespective of the gas atmospheres used during annealing. The increase in the specific capacitance was discussed in terms of increased oxygen vacancies as a result of the

  15. Laser annealing and defect study of chalcogenide photovoltaic materials

    NASA Astrophysics Data System (ADS)

    Bhatia, Ashish

    Cu(In,Ga)Se2 (CIGSe), CuZnSn(S,Se)4(CZTSSe), etc., are the potential chalcogenide semiconductors being investigated for next-generation thin film photovoltaics (TFPV). While the champion cell efficiency of CIGSe has exceeded 20%, CZTSSe has crossed the 10% mark. This work investigates the effect of laser annealing on CISe films, and compares the electrical characteristics of CIGSe (chalcopyrite) and CZTSe (kesterite) solar cells. Chapter 1 through 3 provide a background on semiconductors and TFPV, properties of chalcopyrite and kesterite materials, and their characterization using deep level transient spectroscopy (DLTS) and thermal admittance spectroscopy (TAS). Chapter 4 investigates electrochemical deposition (nonvacuum synthesis) of CISe followed by continuous wave laser annealing (CWLA) using a 1064 nm laser. It is found that CWLA at ≈ 50 W/cm2 results in structural changes without melting and dewetting of the films. While Cu-poor samples show about 40% reduction in the full width at half maximum of the respective x-ray diffraction peaks, identically treated Cu-rich samples register more than 80% reduction. This study demonstrates that an entirely solid-phase laser annealing path exists for chalcopyrite phase formation and crystallization. Chapter 5 investigates the changes in defect populations after pulse laser annealing in submelting regime of electrochemically deposited and furnace annealed CISe films. DLTS on Schottky diodes reveal that the ionization energy of the dominant majority carrier defect state changes nonmonotonically from 215+/-10 meV for the reference sample, to 330+/-10 meV for samples irradiated at 20 and 30 mJ/cm2, and then back to 215+/-10 meV for samples irradiated at 40 mJ/cm2. A hypothesis involving competing processes of diffusion of Cu and laser-induced generation of In vacancies may explain this behavior. Chapter 6 compares the electrical characteristics of chalcopyrite and kesterite materials. Experiments reveal CZTSe cell has an

  16. Automatic setae segmentation from Chaetoceros microscopic images.

    PubMed

    Zheng, Haiyong; Zhao, Hongmiao; Sun, Xue; Gao, Huihui; Ji, Guangrong

    2014-09-01

    A novel image processing model Grayscale Surface Direction Angle Model (GSDAM) is presented and the algorithm based on GSDAM is developed to segment setae from Chaetoceros microscopic images. The proposed model combines the setae characteristics of the microscopic images with the spatial analysis of image grayscale surface to detect and segment the direction thin and long setae from the low contrast background as well as noise which may make the commonly used segmentation methods invalid. The experimental results show that our algorithm based on GSDAM outperforms the boundary-based and region-based segmentation methods Canny edge detector, iterative threshold selection, Otsu's thresholding, minimum error thresholding, K-means clustering, and marker-controlled watershed on the setae segmentation more accurately and completely. PMID:24913015

  17. Effect of annealing on the structure and properties of hot-pressed boron carbide base cermets

    SciTech Connect

    Koval'chenko, M.S.; Laptev, A.V.; Zhidov, A.B.

    1986-02-01

    This paper studies the effect of annealing conditions on the structure and some physicomechanical properties of boron carbidealuminum cermets produced by hot pressing under high pressures. The paper also explores the possibility of regulating the properties of such cermets by heat treatment. Cermets were produced using boron carbide powders of particle sizes up to 100 ..mu..m. As metallic binders, PA-3 aluminum powder and powders of aluminum alloys with improving wetting and adhesional interaction were employed. The microstructures of specimens were studied under an MIM-8 optical microscope. X-ray phase analysis was carried out in a URS-501M diffractometer in Cu K-alpha radiation. The authors found that to obtain boron carbidealuminum materials of maximum strength, it is necessary to perform their liquid-phase pressing under high pressures and dispense with subsequent annealing.

  18. Low-cost ion implantation and annealing technology for solar cells

    NASA Technical Reports Server (NTRS)

    Kirkpatrick, A. H.; Minnucci, J. A.; Greenwald, A. C.

    1980-01-01

    Ion implantation and thermal annealing techniques for processing junctions and back surface layers in solar cells are discussed. Standard 10 keV (31)p(+) junction implants and 25 keV (11)B(+) back surface implants in combination with three-step furnace annealing are used for processing a range of silicon materials and device structures. Cells with efficiencies up to 16.5% AM1 are being produced, and large-area terrestrial cells with implanted junctions and back fields being fabricated in pilot production exhibit average efficiencies in excess of 15% AM1. Thermal annealing methods for removal of the radiation damage caused by implantation should be replaced by transient processing techniques in future production. Design studies have been completed for solar cell processing implanters to support 10 MW/yr and 100 MW/yr production lines, and analyses indicate that implantation costs can be reduced to approximately 1 cent/watt.

  19. Black anneal marking with pulsed fiber lasers

    NASA Astrophysics Data System (ADS)

    Murphy, T.; Harrison, P.; Norman, S.

    2015-07-01

    High contrast marking of metals is used in a wide range of industries. Fiber laser marking of these metals provides non-contact marking with no consumables, offering many advantages over traditional methods of metal marking. The laser creates a permanent mark on the material surface combining heat and oxygen with no noticeable ablation. The focussed beam of the fiber laser in combination with precision control of the heat input is able to treat small areas of the material surface evenly and consistently, which is critical for producing black anneal marks. The marks are highly legible which is ideal for marking serial numbers or small data matrices where traceability is required. This paper reports the experimental study for producing black anneal marks on various grades of stainless steel using fiber lasers. The influence of metal surface finish, beam quality, spot size diameter and pulse duration are investigated for producing both smooth and decorative anneal marks.

  20. Computational multiqubit tunnelling in programmable quantum annealers.

    PubMed

    Boixo, Sergio; Smelyanskiy, Vadim N; Shabani, Alireza; Isakov, Sergei V; Dykman, Mark; Denchev, Vasil S; Amin, Mohammad H; Smirnov, Anatoly Yu; Mohseni, Masoud; Neven, Hartmut

    2016-01-01

    Quantum tunnelling is a phenomenon in which a quantum state traverses energy barriers higher than the energy of the state itself. Quantum tunnelling has been hypothesized as an advantageous physical resource for optimization in quantum annealing. However, computational multiqubit tunnelling has not yet been observed, and a theory of co-tunnelling under high- and low-frequency noises is lacking. Here we show that 8-qubit tunnelling plays a computational role in a currently available programmable quantum annealer. We devise a probe for tunnelling, a computational primitive where classical paths are trapped in a false minimum. In support of the design of quantum annealers we develop a nonperturbative theory of open quantum dynamics under realistic noise characteristics. This theory accurately predicts the rate of many-body dissipative quantum tunnelling subject to the polaron effect. Furthermore, we experimentally demonstrate that quantum tunnelling outperforms thermal hopping along classical paths for problems with up to 200 qubits containing the computational primitive. PMID:26739797

  1. Stochastic annealing simulation of cascades in metals

    SciTech Connect

    Heinisch, H.L.

    1996-04-01

    The stochastic annealing simulation code ALSOME is used to investigate quantitatively the differential production of mobile vacancy and SIA defects as a function of temperature for isolated 25 KeV cascades in copper generated by MD simulations. The ALSOME code and cascade annealing simulations are described. The annealing simulations indicate that the above Stage V, where the cascade vacancy clusters are unstable,m nearly 80% of the post-quench vacancies escape the cascade volume, while about half of the post-quench SIAs remain in clusters. The results are sensitive to the relative fractions of SIAs that occur in small, highly mobile clusters and large stable clusters, respectively, which may be dependent on the cascade energy.

  2. Computational multiqubit tunnelling in programmable quantum annealers

    PubMed Central

    Boixo, Sergio; Smelyanskiy, Vadim N.; Shabani, Alireza; Isakov, Sergei V.; Dykman, Mark; Denchev, Vasil S.; Amin, Mohammad H.; Smirnov, Anatoly Yu; Mohseni, Masoud; Neven, Hartmut

    2016-01-01

    Quantum tunnelling is a phenomenon in which a quantum state traverses energy barriers higher than the energy of the state itself. Quantum tunnelling has been hypothesized as an advantageous physical resource for optimization in quantum annealing. However, computational multiqubit tunnelling has not yet been observed, and a theory of co-tunnelling under high- and low-frequency noises is lacking. Here we show that 8-qubit tunnelling plays a computational role in a currently available programmable quantum annealer. We devise a probe for tunnelling, a computational primitive where classical paths are trapped in a false minimum. In support of the design of quantum annealers we develop a nonperturbative theory of open quantum dynamics under realistic noise characteristics. This theory accurately predicts the rate of many-body dissipative quantum tunnelling subject to the polaron effect. Furthermore, we experimentally demonstrate that quantum tunnelling outperforms thermal hopping along classical paths for problems with up to 200 qubits containing the computational primitive. PMID:26739797

  3. Quantum annealing correction for random Ising problems

    NASA Astrophysics Data System (ADS)

    Pudenz, Kristen L.; Albash, Tameem; Lidar, Daniel A.

    2015-04-01

    We demonstrate that the performance of a quantum annealer on hard random Ising optimization problems can be substantially improved using quantum annealing correction (QAC). Our error correction strategy is tailored to the D-Wave Two device. We find that QAC provides a statistically significant enhancement in the performance of the device over a classical repetition code, improving as a function of problem size as well as hardness. Moreover, QAC provides a mechanism for overcoming the precision limit of the device, in addition to correcting calibration errors. Performance is robust even to missing qubits. We present evidence for a constructive role played by quantum effects in our experiments by contrasting the experimental results with the predictions of a classical model of the device. Our work demonstrates the importance of error correction in appropriately determining the performance of quantum annealers.

  4. Effect of annealing time on the physical properties of ultrasonically sprayed CdS:In thin films

    NASA Astrophysics Data System (ADS)

    Karakaya, S.; Gencyılmaz, O.; Ozbas, O.

    2012-09-01

    In this work, CdS and In doped CdS films were prepared by ultrasonic spray pyrolysis (USP) technique and were annealed at 450 °C in an air atmoshpere. The optical constants (n and k) and thicknesses of the films were determined by spectroscopic ellipsometry. Transmission and absorbance spectra were taken by UV spectrophotometer. Optical method was used to determine the band gap value of the films. Atomic force microscope (AFM) images were taken to see the effect of annealing time on surface topography and roughness of the films. Electrical resistivities of the films were analyzed by four probe technique. As a result, the application potential of annealed CdS:In films for photovoltaic solar cells and optoelectronic applications were investigated.

  5. Quantum annealing correction with minor embedding

    NASA Astrophysics Data System (ADS)

    Vinci, Walter; Albash, Tameem; Paz-Silva, Gerardo; Hen, Itay; Lidar, Daniel A.

    2015-10-01

    Quantum annealing provides a promising route for the development of quantum optimization devices, but the usefulness of such devices will be limited in part by the range of implementable problems as dictated by hardware constraints. To overcome constraints imposed by restricted connectivity between qubits, a larger set of interactions can be approximated using minor embedding techniques whereby several physical qubits are used to represent a single logical qubit. However, minor embedding introduces new types of errors due to its approximate nature. We introduce and study quantum annealing correction schemes designed to improve the performance of quantum annealers in conjunction with minor embedding, thus leading to a hybrid scheme defined over an encoded graph. We argue that this scheme can be efficiently decoded using an energy minimization technique provided the density of errors does not exceed the per-site percolation threshold of the encoded graph. We test the hybrid scheme using a D-Wave Two processor on problems for which the encoded graph is a two-level grid and the Ising model is known to be NP-hard. The problems we consider are frustrated Ising model problem instances with "planted" (a priori known) solutions. Applied in conjunction with optimized energy penalties and decoding techniques, we find that this approach enables the quantum annealer to solve minor embedded instances with significantly higher success probability than it would without error correction. Our work demonstrates that quantum annealing correction can and should be used to improve the robustness of quantum annealing not only for natively embeddable problems but also when minor embedding is used to extend the connectivity of physical devices.

  6. Performance of quantum annealing in solving optimization problems: A review

    NASA Astrophysics Data System (ADS)

    Suzuki, S.

    2015-02-01

    Quantum annealing is one of the optimization method for generic optimization problems. It uses quantum mechanics and is implemented by a quantum computer ideally. At the earlier stage, several numerical experiments using conventional computers have provided results showing that quantum annealing produces an answer faster than simulated annealing, a classical counterpart of quantum annealing. Later, theoretical and numerical studies have shown that there are drawbacks in quantum annealing. The power of quantum annealing is still an open problem. What makes quantum annealing a hot topic now is that a quantum computer based on quantum annealing is manufactured and commercialized by a Canadian company named D-Wave Systems. In the present article, we review the study of quantum annealing, focusing mainly on its power.

  7. Photoluminescence enhancement in CdS quantum dots by thermal annealing

    PubMed Central

    2012-01-01

    The photoluminescence behavior of CdS quantum dots in initial growth stage was studied in connection with an annealing process. Compared to the as-synthesized CdS quantum dots (quantum efficiency ≅ 1%), the heat-treated sample showed enhanced luminescence properties (quantum efficiency ≅ 29%) with a narrow band-edge emission. The simple annealing process diminished the accumulated defect states within the nanoparticles and thereby reduced the nonradiative recombination, which was confirmed by diffraction, absorption, and time-resolved photoluminescence. Consequently, the highly luminescent and defect-free nanoparticles were obtained by a facile and straightforward process. PMID:22931230

  8. Rock melting tool with annealer section

    DOEpatents

    Bussod, Gilles Y.; Dick, Aaron J.; Cort, George E.

    1998-01-01

    A rock melting penetrator is provided with an afterbody that rapidly cools a molten geological structure formed around the melting tip of the penetrator to the glass transition temperature for the surrounding molten glass-like material. An annealing afterbody then cools the glass slowly from the glass transition temperature through the annealing temperature range to form a solid self-supporting glass casing. This allows thermally induced strains to relax by viscous deformations as the molten glass cools and prevents fracturing of the resulting glass liner. The quality of the glass lining is improved, along with its ability to provide a rigid impermeable casing in unstable rock formations.

  9. Annealing Increases Stability Of Iridium Thermocouples

    NASA Technical Reports Server (NTRS)

    Germain, Edward F.; Daryabeigi, Kamran; Alderfer, David W.; Wright, Robert E.; Ahmed, Shaffiq

    1989-01-01

    Metallurgical studies carried out on samples of iridium versus iridium/40-percent rhodium thermocouples in condition received from manufacturer. Metallurgical studies included x-ray, macroscopic, resistance, and metallographic studies. Revealed large amount of internal stress caused by cold-working during manufacturing, and large number of segregations and inhomogeneities. Samples annealed in furnace at temperatures from 1,000 to 2,000 degree C for intervals up to 1 h to study effects of heat treatment. Wire annealed by this procedure found to be ductile.

  10. Enhancement of saturation magnetization in Cr-ion implanted silicon by high temperature annealing

    NASA Astrophysics Data System (ADS)

    Yang, Shuang; Zhang, Wenyong; Chen, Jihong; Zhou, Zhongpo; Ai, Zhiwei; Guo, Liping; Liu, Congxiao; Du, Honglin

    2011-08-01

    Magnetic properties and microstructure of Cr-implanted Si have been investigated by alternating gradient magnetometer (AGM), superconducting quantum interference device (SQUID) magnetometer, and transmission electron microscopy (TEM). p-Type (1 0 0) Si wafers were implanted at 200 keV at room temperature with a dosage of 1 × 10 16 cm -2 Cr ions and then annealed at 600-900 °C for 5 min. The effect of annealing on the structure and magnetic properties of Cr-implanted Si is studied. The as-implanted sample shows a square M-H loop at low temperature. Magnetic signal becomes weaker after short time annealing of the as-implanted sample at 600 °C, 700 °C, and 800 °C. However, the 900 °C annealed sample exhibits large saturation magnetization at room temperature. TEM images reveal that the implanting process caused amorphization of Si, while annealing at 900 °C led to partial recovery of the crystal. The enhancement of saturation magnetization can be explained by the redistribution and accumulation of Cr atoms in the vacancy-rich region of Si during annealing.

  11. Accumulative Roll Bonding and Post-Deformation Annealing of Cu-Al-Mn Shape Memory Alloy

    NASA Astrophysics Data System (ADS)

    Moghaddam, Ahmad Ostovari; Ketabchi, Mostafa; Afrasiabi, Yaser

    2014-09-01

    Accumulative roll bonding is a severe plastic deformation process used for Cu-Al-Mn shape memory alloy. The main purpose of this study is to investigate the possibility of grain refinement of Cu-9.5Al-8.2Mn (in wt.%) shape memory alloy using accumulative roll bonding and post-deformation annealing. The alloy was successfully subjected to 5 passes of accumulative roll bonding at 600 °C. The microstructure, properties as well as post-deformation annealing of this alloy were investigated by optical microscopy, scanning electron microscopy, x-ray diffraction, differential scanning calorimeter, and bend and tensile testing. The results showed that after 5 passes of ARB at 600 °C, specimens possessed α + β microstructure with the refined grains, but martensite phases and consequently shape memory effect completely disappeared. Post-deformation annealing was carried out at 700 °C, and the martensite phase with the smallest grain size (less than 40 μm) was obtained after 150 s of annealing at 700 °C. It was found that after 5 passes of ARB and post-deformation annealing, the stability of SME during thermal cycling improved. Also, tensile properties of alloys significantly improved after post-deformation annealing.

  12. Accumulative Roll Bonding and Post-Deformation Annealing of Cu-Al-Mn Shape Memory Alloy

    NASA Astrophysics Data System (ADS)

    Moghaddam, Ahmad Ostovari; Ketabchi, Mostafa; Afrasiabi, Yaser

    2014-12-01

    Accumulative roll bonding is a severe plastic deformation process used for Cu-Al-Mn shape memory alloy. The main purpose of this study is to investigate the possibility of grain refinement of Cu-9.5Al-8.2Mn (in wt.%) shape memory alloy using accumulative roll bonding and post-deformation annealing. The alloy was successfully subjected to 5 passes of accumulative roll bonding at 600 °C. The microstructure, properties as well as post-deformation annealing of this alloy were investigated by optical microscopy, scanning electron microscopy, x-ray diffraction, differential scanning calorimeter, and bend and tensile testing. The results showed that after 5 passes of ARB at 600 °C, specimens possessed α + β microstructure with the refined grains, but martensite phases and consequently shape memory effect completely disappeared. Post-deformation annealing was carried out at 700 °C, and the martensite phase with the smallest grain size (less than 40 μm) was obtained after 150 s of annealing at 700 °C. It was found that after 5 passes of ARB and post-deformation annealing, the stability of SME during thermal cycling improved. Also, tensile properties of alloys significantly improved after post-deformation annealing.

  13. Surface modification of cellulose acetate membrane using thermal annealing to enhance produced water treatment

    SciTech Connect

    Kusworo, T. D. Aryanti, N. Firdaus, M. M. H.; Sukmawati, H.

    2015-12-29

    This study is performed primarily to investigate the effect of surface modification of cellulose acetate using thermal annealing on the enhancement of membrane performance for produced water treatment. In this study, Cellulose Acetate membranes were casted using dry/wet phase inversion technique. The effect of additive and post-treatment using thermal annealing on the membrane surface were examined for produced water treatment. Therma annealing was subjected to membrane surface at 60 and 70 °C for 5, 10 and 15 second, respectively. Membrane characterizations were done using membrane flux and rejection with produced water as a feed, Scanning Electron Microscopy (SEM) and Fourier Transform Infra Red (FTIR) analysis. Experimental results showed that asymmetric cellulose acetate membrane can be made by dry/wet phase inversion technique. The results from the Scanning Electron Microscopy (FESEM) analysis was also confirmed that polyethylene glycol as additivie in dope solution and thermal annealing was affected the morphology and membrane performance for produced water treatment, respectively. Scanning electron microscopy micrographs showed that the selective layer and the substructure of membrane became denser and more compact after the thermal annealing processes. Therefore, membrane rejection was significantly increased while the flux was slighty decreased, respectively. The best membrane performance is obtained on the composition of 18 wt % cellulose acetate, poly ethylene glycol 5 wt% with thermal annealing at 70° C for 15 second.

  14. Tailoring the magnetic properties and magnetorheological behavior of spinel nanocrystalline cobalt ferrite by varying annealing temperature.

    PubMed

    Sedlacik, Michal; Pavlinek, Vladimir; Peer, Petra; Filip, Petr

    2014-05-14

    Magnetic nanoparticles of spinel nanocrystalline cobalt ferrite were synthesized via the sol-gel method and subsequent annealing. The influence of the annealing temperature on the structure, magnetic properties, and magnetorheological effect was investigated. The finite crystallite size of the particles, determined by X-ray diffraction and the particle size observed via transmission electron microscopy, increased with the annealing temperature. The magnetic properties observed via a vibrating sample magnetometer showed that an increase in the annealing temperature leads to the increase in the magnetization saturation and, in contrast, a decrease in the coercivity. The effect of annealing on the magnetic properties of ferrite particles has been explained by the recrystallization process at high temperatures. This resulted in grain size growth and a decrease in an imposed stress relating to defects in the crystal lattice structure of the nanoparticles. The magnetorheological characteristics of suspensions of ferrite particles in silicone oil were measured using a rotational rheometer equipped with a magnetic field generator in both steady shear and small-strain oscillatory regimes. The magnetorheological performance expressed as a relative increase in the magnetoviscosity appeared to be significantly higher for suspensions of particles annealed at 1000 °C. PMID:24668306

  15. Surface modification of cellulose acetate membrane using thermal annealing to enhance produced water treatment

    NASA Astrophysics Data System (ADS)

    Kusworo, T. D.; Aryanti, N.; Firdaus, M. M. H.; Sukmawati, H.

    2015-12-01

    This study is performed primarily to investigate the effect of surface modification of cellulose acetate using thermal annealing on the enhancement of membrane performance for produced water treatment. In this study, Cellulose Acetate membranes were casted using dry/wet phase inversion technique. The effect of additive and post-treatment using thermal annealing on the membrane surface were examined for produced water treatment. Therma annealing was subjected to membrane surface at 60 and 70 °C for 5, 10 and 15 second, respectively. Membrane characterizations were done using membrane flux and rejection with produced water as a feed, Scanning Electron Microscopy (SEM) and Fourier Transform Infra Red (FTIR) analysis. Experimental results showed that asymmetric cellulose acetate membrane can be made by dry/wet phase inversion technique. The results from the Scanning Electron Microscopy (FESEM) analysis was also confirmed that polyethylene glycol as additivie in dope solution and thermal annealing was affected the morphology and membrane performance for produced water treatment, respectively. Scanning electron microscopy micrographs showed that the selective layer and the substructure of membrane became denser and more compact after the thermal annealing processes. Therefore, membrane rejection was significantly increased while the flux was slighty decreased, respectively. The best membrane performance is obtained on the composition of 18 wt % cellulose acetate, poly ethylene glycol 5 wt% with thermal annealing at 70° C for 15 second.

  16. Improved zircon fission-track annealing model based on reevaluation of annealing data

    SciTech Connect

    Guedes, S.; Moreira, Pedro; Devanathan, Ramaswami; Weber, William J.; Hadler, J. C.

    2012-11-10

    The thermal recovery (annealing) of mineral structure modified by the passage of fission fragments has long been studied by the etching technique. In minerals like apatite and zircon, the annealing kinetics are fairly well constrained from the hour to the million-year timescale and have been described by empirical and semi-empirical equations. On the other hand, laboratory experiments, in which ion beams interact with minerals and synthetic ceramics, have shown that there is a threshold temperature beyond which thermal recovery impedes ion-induced amorphization. In this work, it is assumed that this behavior can be extended to the annealing of fission tracks in minerals. It is proposed that there is a threshold temperature, T 0, beyond which fission tracks are erased within a time t 0, which is independent of the current state of lattice deformation. This implies that iso-annealing curves should converge to a fanning point in the Arrhenius pseudo-space (ln t vs. 1/T). Based on the proposed hypothesis, and laboratory and geological data, annealing equations are reevaluated. The geological timescale estimations of a model arising from this study are discussed through the calculation of partial annealing zone and closure temperature, and comparison with geological sample constraints found in literature. It is shown that the predictions given by this model are closer to field data on closure temperature and partial annealing zone than predictions given by previous models.

  17. Improved zircon fission-track annealing model based on reevaluation of annealing data

    SciTech Connect

    Guedes, Sandro; Moreira, Pedro A.F.P.; Devanathan, Ram; Weber, William J; Hadler, Julio C

    2013-01-01

    The thermal recovery (annealing) of mineral structure modified by the passage of fission fragments has long been studied by the etching technique. In minerals like apatite and zircon, the annealing kinetics are fairly well constrained from the hour to the million-year timescale and have been described by empirical and semi-empirical equations. On the other hand, laboratory experiments, in which ion beams interact with minerals and synthetic ceramics, have shown that there is a threshold temperature beyond which thermal recovery impedes ion-induced amorphization. In this work, it is assumed that this behavior can be extended to the annealing of fission tracks in minerals. It is proposed that there is a threshold temperature, T0, beyond which fission tracks are erased within a time t0, which is independent of the current state of lattice deformation. This implies that iso-annealing curves should converge to a fanning point in the Arrhenius pseudo-space (ln t vs. 1/T). Based on the proposed hypothesis, and laboratory and geological data, annealing equations are reevaluated. The geological timescale estimations of a model arising from this study are discussed through the calculation of partial annealing zone and closure temperature, and comparison with geological sample constraints found in literature. It is shown that the predictions given by this model are closer to field data on closure temperature and partial annealing zone than predictions given by previous models.

  18. Effects of pre-annealing on the uni- and bi-axial stretching behavior of poly(ethylene naphthalate) films

    SciTech Connect

    Abe, T. Takarada, W. Kikutani, T.

    2014-05-15

    Effect of pre-annealing on stress and birefringence behavior of poly(ethylene naphthalate) (PEN) films during stretching and relaxation processes was investigated. Amorphous and non-oriented PEN films were pre-annealed under the conditions of different temperatures and periods. The pre-annealed films were stretched uniaxially or equi-biaxially and then relaxed at fixed length. It was found that pre-annealing did not cause any notable change for the initial behavior of refractive indices variation, whereas the behaviors after necking were significantly affected. Through the comparison between in-plane and out-of-plane birefringence and the analysis of wide-angle x-ray diffraction patterns of drawn films of both stretching modes, it was confirmed that the orientation of naphthalene ring in the film plane was enhanced by pre-annealing.

  19. Microstructural Evolutions During Annealing of Plastically Deformed AISI 304 Austenitic Stainless Steel: Martensite Reversion, Grain Refinement, Recrystallization, and Grain Growth

    NASA Astrophysics Data System (ADS)

    Naghizadeh, Meysam; Mirzadeh, Hamed

    2016-06-01

    Microstructural evolutions during annealing of a plastically deformed AISI 304 stainless steel were investigated. Three distinct stages were identified for the reversion of strain-induced martensite to austenite, which were followed by the recrystallization of the retained austenite phase and overall grain growth. It was shown that the primary recrystallization of the retained austenite postpones the formation of an equiaxed microstructure, which coincides with the coarsening of the very fine reversed grains. The latter can effectively impair the usefulness of this thermomechanical treatment for grain refinement at both high and low annealing temperatures. The final grain growth stage, however, was found to be significant at high annealing temperatures, which makes it difficult to control the reversion annealing process for enhancement of mechanical properties. Conclusively, this work unravels the important microstructural evolution stages during reversion annealing and can shed light on the requirements and limitations of this efficient grain refining approach.

  20. Microstructural Evolutions During Annealing of Plastically Deformed AISI 304 Austenitic Stainless Steel: Martensite Reversion, Grain Refinement, Recrystallization, and Grain Growth

    NASA Astrophysics Data System (ADS)

    Naghizadeh, Meysam; Mirzadeh, Hamed

    2016-08-01

    Microstructural evolutions during annealing of a plastically deformed AISI 304 stainless steel were investigated. Three distinct stages were identified for the reversion of strain-induced martensite to austenite, which were followed by the recrystallization of the retained austenite phase and overall grain growth. It was shown that the primary recrystallization of the retained austenite postpones the formation of an equiaxed microstructure, which coincides with the coarsening of the very fine reversed grains. The latter can effectively impair the usefulness of this thermomechanical treatment for grain refinement at both high and low annealing temperatures. The final grain growth stage, however, was found to be significant at high annealing temperatures, which makes it difficult to control the reversion annealing process for enhancement of mechanical properties. Conclusively, this work unravels the important microstructural evolution stages during reversion annealing and can shed light on the requirements and limitations of this efficient grain refining approach.