ring defects in the otherwise hexagonal structure of the un- derlying lattice. ..... and relatively defect free structure. For non-axial strains such ...

The objective of this program was to seek improved process control and weldment reliability during laser welding of automotive aluminum alloys while retaining the high speed and accuracy of the laser beam welding process. The effects of various welding variables on the loss of alloying elements and the formation of porosity and other geometric weld defects such as underfill and overfill were ...

Defect-free pyrite (100) surfaces were generated and a controlled manipulation of sulfur defect density at these surfaces was performed. Sulfur species of different coordination environments at the surface were probed by S 2p photoemission in combination with theoretical modeling of S 2p core-level shifts. A strict structural assignment of S 2p ...

High performance polymer based-cements (i.e. cements having a water to cement ratio, w/a, close to 0.1) almost totally free of defect, have been developed in recent years claiming a great interest for their very high tensile strength compared with traditional cements. These materials can be produced utilizing very simple unit operations and further formed in complex shapes with high surface ...

The results of a first-principles study based on density functional theory on the interaction of Melamine molecule with both defected and defect free graphene nanoribbons(GNRs) are reported. The calculated results show that Melamine molecules are rather strongly bound to the surface of both defect and defect free ...

A method for achieving a substantially defect free SGOI substrate which includes a SiGe layer that has a high Ge content of greater than about 25 atomic % using a low temperature wafer bonding technique is described. The wafer bonding process described in...

Defect-free, ultrahigh flux integrally-skinned asymmetric membranes having extremely thin surface layers (<0.2 .mu.m) comprised of glassy polymers are disclosed. The membranes are formed by casting an appropriate drope followed by forced convective evaporation of solvent to obtain a dry phase separated asymmetrical structure. The ...

The authors report on the achievement of nearly defect-free, vertically aligned InGaN/GaN dot-in-a-wire nanoscale heterostructures grown directly on Si(111) substrates by molecular beam epitaxy. Strong green, yellow, and amber emission, with a room temperature internal quantum efficiency of ~45% of that measured at low temperature (~10 K), was ...

In this work, nanoporous titania top layers were deposited by dip-coating process on microporous alpha-alumina substrates using the sol-gel process. The alumina substrates were synthesized by slip casting method using Taguchi optimising approach. The microporous substrate was then used to coat nanoporous titania layers by the sol-gel method. The thickness, pore size, structure ...

The research of this period has involved the growth and characterization of cubic beta-SiC on hexagonal alpha-SiC substrates. The resulting films were virtually defect free in contrast to those grown on Si. Additional research has included ion implantation at temperatures sufficient to achieve significant dynamic annealing and p-type ...

. This indicates that two nanowires impinged. More evidence supporting this argument is the occurrence of L their growth is orthogonal to the 111 B, in- creasing the probability that nanowires impinge. This is most 111 . It is interesting to note that 110 nanowires are defect free. Twinned structures in zinc

The production of functional molecular architectures through self-assembly is commonplace in biology, but despite advances, it is still a major challenge to achieve similar complexity in the laboratory. Self-assembled structures that are reproducible and virtually defect free are of interest for applications in ...

The theoretical strength of a material is the stress required to deform an infinite, defect-free crystal. Achieving the theoretical strength of a material experimentally is hindered by the ability to create and mechanically test an absolutely defect-free material. Here we show that through annealing it is possible to employ the ...

Adhesion between zeolites and polymers is a central factor in achieving defect-free mixed-matrix membranes for energy-efficient gas separations. In this work, atomic force microscopy (AFM) was used to measure adhesion forces between a pure silica MFI (ZSM-5: Zeolite Socony Mobil-Five) (010) zeolite probe and a series of polyimide (Matrimid 5218, 6FDA-DAM, ...

In the present investigation, the individual and interactive effects of the main welding parameters on weld quality of plasma arc keyhole welding of conventional structural steel, high strength microalloyed steel and strong formable microalloyed steel have been examined using welding of butt joints with a square groove in various welding positions, and welding of joint roots ...

Creating a regular surface pattern on the nanometre scale is important for many technological applications, such as the periodic arrays constructed by optical microlithography that are used as separation media in electrophoresis, and island structures used for high-density magnetic recording devices. Block copolymer patterns can also be used for lithography on length scales ...

A new class of fabrication methods for embedded distributed grating structures is claimed, together with optical devices which include such structures. These new methods are the only known approach to making defect-free high-dielectric contrast grating structures, which are smaller and more efficient than are ...

Iridium alloys are used as fuel cladding in radioisotope thermoelectric generators due to their high-melting point, high- temperature strength, and oxidation and corrosion resistance. Although iridium has a face-centered cubic crystal structure, it undergoes a distinct ductile-to-brittle transition characteristic of many body-centered cubic metals. Improved ductility in the ...

The development of a nearly defect-free reticle blank is an important challenge facing extreme ultraviolet lithography (EUVL). The core element of an EUVL reticle blank is the reflective Mo/Si multilayer film, and deposition of Mo/Si on very small substrate defects can result in critical Mo/Si phase defects. In this article we present a method for repairing Mo/Si multilayer ...

Nanoparticles have attracted considerable interest recently due to their size-dependent, quantum confinement characteristics, which make them attractive for an array of optical, magnetic, and electronic devices. For nanoparticles to be employed in an array of commercial and industrial applications, a technique for the facile, site-selective assembly of homogeneous, densely packed, ...

Fabrication of defect free EUV mask is one of the most critical roadblocks for implementing EUV lithography into semiconductor high volume manufacturing for 22nm half-pitch (HP) node and beyond. At the same time, development of quality assurance process for the defect free EUV mask is also another critical ...

Defect-free Ge-on-insulator (GOI) with various crystal orientations is essential to realize high-speed and multifunctional devices. Seeded rapid-melting growth of GOI is investigated as a function of seed-orientations and growth-directions. From (100)-oriented Si seeds, Ge growth with a (100) orientation propagates for all growth-directions, however, rotational-growth is ...

We report the growth of ZnSe nanowires and nanoneedles using molecular beam epitaxy (MBE). Different growth regimes were found, depending on growth temperature and the Zn-Se flux ratio. By employing a combined MBE growth of nanowires and nanoneedles without any postprocessing of the sample, we achieved an efficient suppression of stacking fault defects. This is confirmed by ...

A detailed structural investigation of Heatpulse rapid thermal annealed ion-implanted Si was carried out using TEM. Defect-free material was obtained after an 1100 exp 0 C/10 s anneal for 80 keV 2 x 10 exp 15 exp 75 As implanted Si, while dislocation loop...

As chips further shrink toward smaller scales, fabrication processes based on the self-assembly of individual particles into patterns or structures are often sought. One of the most popular techniques for two-dimensional assembly (self-assembled monolayers) is based on capillary forces acting on particles placed at a liquid interface. Capillarity-induced clustering, however, ...

As chips further shrink toward smaller scales, fabrication processes based on the self-assembly of individual particles into patterns or structures are often sought. One of the most popular techniques for two-dimensional assembly (self-assembled monolayers) is based on capillary forces acting on particles placed at a liquid interface. Capillarity-induced clustering, however, ...

VPI-5 transforms to AlPO(sub 4)-8 under mild thermal treatment (100(degree)C, 18 hrs). HRTEM micrographs, oriented normal to the c axis, show extensive defect-free regions in VPI-5, while slip planes normal to the c axis are found in AlPO(sub 4)-8. Analys...

The zero-temperature energies and equilibrium volume expansions of point-defect free asymmetrical grain boundaries (GBs) involving the four densest planes in fcc bicrystals (with some higher-index plane on the other side of the interface) have been determ...

The top-down nanomanufacturing technique is approaching its theoretic limits and processes such as e-beam lithography are extremely costly. In contrast, the bottom-up method such as self-assembly can easily reach nanometer (even sub-nanometer) feature sizes. One drawback of self assembly, however, is the difficulty to achieve large scale, defect-free ...

A wavelet-transform-based technique to enhance defect detection in a carbon fiber composite plate interrogated using ultrasonic Lamb waves and incorporating an optical fiber receiver is described. Fundamental symmetric (SO) Lamb waves were introduced into the sample plates using a conventional piezoelectric transducer operating at a frequency of around 250 kHz. Coupling into the plates was ...

Herein we report on the formation and characterization of pure polyamide thin film composite (TFC) and zeolite-polyamide thin film nanocomposite (TFN) reverse osmosis (RO) membranes. Four different physical-chemical post-treatment combinations were applied after the interfacial polymerization reaction to change the molecular structure of polyamide and zeolite-polyamide thin ...

Nanocomposite assemblies of poly(3,4-ethylenedioxythiophene) (PEDOT), embedded with (a) fluoro alkyl phosphate based ionic liquid functionalized graphene (ILFG) and (b) reduced graphene oxide (RGO) prepared from a modified Hummers' method, have been synthesized. Defect free graphene nanosheets within the size of a few nanometers were ...

Strained-layer superlattices are periodic structures composed of mismatched layers whose thickness does not exceed the critical value for elastic deformation, thus avoiding the generation of misfit dislocations. For semiconductor applications this greatly increases the range of alloys available for high quality (neraly defect-free) materials and provides ...

SAS (Self-Aligned Source) process has been widely adopted on manufacturing NOR Flash devices. To form the SAS structure, the compromise between small space patterning and sufficiently removing photo resist residue in topographical substrate has been a critical challenge as the device scaling down. In this study, photo simulation, layout optimization, resist processing and ...

This report documents work performed to develop materials systems for use in the ceramic packaging of Ga:As integrated circuits. Topics under study at Penn State are: dielectrics produced from Macro-Defect-Free (MDF) cements. Both aluminate- and silicate-based cements were studied. The objectives of the first year's work have been to show that suitable test tablets ...

This report documents work performed to develop materials systems for use in the ceramic packaging of Ga:As integrated circuits. Topics under study at Penn State are: dielectrics produced from Macro-Defect-Free (MDF) cements. Both aluminate and silicate based cements have been studied. The objectives of the first year's work have been to show that suitable test tablets can be ...

Fabrication and characterization of nanoscale Si structures are of great technological importance due to their potential applications in nanoelectronic devices. In this dissertation, I investigate structural, optical and electrical properties of Si nanocrystals that are formed by solid-phase crystallization of nanometer-thick (2.5--20 nm) amorphous Si ...

Green state joining of structural ceramics has shown its potential for forming large, complex components. In this work, methods of green state joining of silicon carbide using polymer precursors are explored. Pastes containing either polycarbosilane (PCS) or Allylhydridopolycarbosilane (AHPCS) are used in the joining process. It has been demonstrated that joints formed under ...

... Accession Number : ADA096747. Title : Defect-Free, Edge Polishing of Lithium Niobate and Other Optical Crystals. Descriptive Note : Final rept.,. ...

Squeeze casting is the term designating solidification of liquid metal under pressure. Pressure during solidification helps achieve defect-free castings with improved metallurgical properties. Through the work described here, this process has been adapted to manufacture composite materials at affordable costs. A preheated, porous ceramic preform is placed ...

Whereas considerable interest exists in self-assembly of well-ordered, porous "inverse opal" structures for optical, electronic, and (bio)chemical applications, uncontrolled defect formation has limited the scale-up and practicality of such approaches. Here we demonstrate a new method for assembling highly ordered, crack-free inverse opal films over a centimeter scale. ...

Whereas considerable interest exists in self-assembly of well-ordered, porous �inverse opal� structures for optical, electronic, and (bio)chemical applications, uncontrolled defect formation has limited the scale-up and practicality of such approaches. Here we demonstrate a new method for assembling highly ordered, crack-free inverse opal films over a centimeter scale. ...

An improved vacuum fusion bonding structure and process for aligned bonding of large area glass plates, patterned with microchannels and access holes and slots, for elevated glass fusion temperatures. Vacuum pumpout of all components is through the bottom platform which yields an untouched, defect free top surface which greatly ...

An improved vacuum fusion bonding structure and process for aligned bonding of large area glass plates, patterned with microchannels and access holes and slots, for elevated glass fusion temperatures. Vacuum pumpout of all the components is through the bottom platform which yields an untouched, defect free top surface which greatly ...

Using density-functional theory in combination with a thermodynamic formalism we calculate the relative stability of various structural models of the polar O-terminated (0001�)-O surface of ZnO. Model surfaces with different concentrations of oxygen vacancies and hydrogen adatoms are considered. Assuming that the surfaces are in thermodynamic equilibrium with an O2 and H2 ...

In this paper, we present our studies on polystyrene-b-polymethylmethacrylate (PS-b-PMMA) block copolymer systems to produce cylindrical morphology in the thin film configuration. More specifically, we focus on the different accessible parameters to optimize the processing conditions for the self-assembly of this block copolymer. We studied the self-assembly process of the block copolymer film ...

The GaP-based dilute nitride Ga(NAsP) reveals a direct band gap and first laser device operation based on GaP substrate have been demonstrated recently. Since the lattice mismatch between GaP and Si is very small and the defect free deposition of thick GaP/Ga(NP) sequences on off-oriented Si substrate have been reported in literature, the epitaxial ...

Reduced parasitic capacitances, latchup elimination, increased radiation hardeness and three dimensional integration are among the main driving forces behind the Silicon-On -Insulator (SOI) technology. Higher speed and increased radiation tolerance of SOI devices make SOI the prefered material for military applications. Epitaxial lateral overgrowth, graphite strip heater recrystallization, ...

Catalyst-free growth of (In)GaN nanowires on (001) silicon substrate by plasma-assisted molecular beam epitaxy is demonstrated. The nanowires with diameter ranging from 10 to 50 nm have a density of 1-2 x 10(11) cm(-2). P- and n-type doping of the nanowires is achieved with Mg and Si dopant species, respectively. Structural characterization by ...

III-V nanowires have many attractive electrical properties, but only recently has control over the planar defect density been achieved. We correlate the nanowire defect structure with electronic properties by growing InAs nanowires with a growth temperature tunable defect density in a home-built MOVPE reactor^1. Multiple field effect transistors (FETs) ...

Computer simulations reveal how photoinduced chemical reactions in polymeric mixtures can be exploited to create long-range order in materials with features that range from the submicron to the nanoscale. The process is initiated by shining a spatially uniform light on a photosensitive AB binary blend, which thereby undergoes both a reversible chemical reaction and a phase separation. When a ...

We demonstrate numerically that a cavity can be induced in a defect-free photonic crystal slab made of photosensitive material such as chalcogenide glass. A key advantage of the design is the possibility for complete post-processing in an otherwise defect-free structure, and the cavity can thus be formed anywhere in the photonic crystal. We demonstrate ...

Nearly defect-free InN microcrystals grown on Si(111) substrates have been realized by plasma-assisted molecular beam epitaxy. High-resolution transmission electron microscope images reveal that these microcrystals exhibit single-crystalline wurtzite structure. Low temperature photoluminescence (PL) shows a strong emission peak at 0.679 eV with a very ...

Many important materials cannot be grown as single crystals in bulk form because strain destroys long-range crystallinity. Among them, alloys of group IV semiconductors, specifically SiGe alloys, have significant technological value. Using nanomembrane strain engineering methods, we demonstrate the fabrication of fully elastically relaxed Si(1-x)Ge(x) nanomembranes (NMs) for use as growth ...

Ultrahigh-reflectance mirrors are essential optical elements of the most sophisticated optical instruments devised over the entire frequency spectrum. In the X-ray regime, super-polished mirrors with close to 100% reflectivity are routinely used at grazing angles of incidence. However, at large angles of incidence, and particularly at normal incidence, such high reflectivity has not yet been ...

This paper reports on the brittle intermetallic compound Nb{sub 3}Sn produced in multifilamentary form by using ductile precursor materials and a final diffusion heat treatment. The widely used bronze route processed conductors can not explore completely the critical current capabilities of Nb{sub 3}Sn because of the high amount of CuSn in the conductor cross section. Other processes can ...

We analyse the influence of uncharged N vacancies (neutral F centres), created either under conditions of AlN nanotube growth or by its soft irradiation, on the atomic and electronic structure. Periodic one-dimensional (1D) density functional theory (DFT) calculations on models of defective single-walled nanotubes (SW NTs) allow us to analyse how NT chirality and concentration ...

The temperature and concentration dependences of the self-assembly onto graphite from solution of a series of molecular building blocks able to form nanoporous structures are analyzed experimentally by in situ scanning tunneling microscopy. It is shown that the commonly observed coexistence of dense and nanoporous domains results from kinetic blockades rather than a ...

Using a scanning tunneling microscope (STM), we investigated atomic images of disordered regions in three different grades of graphite crystals in air: (1) single-crystal flake graphite (Kish graphite), (2) highly oriented pyrolytic graphite (HOPG) and (3) pyrolytic graphite (PG). In HOPG and Kish graphites, we found unusual super-structures of graphite crystal located near ...

Planar supported lipid bilayers (PSLBs) have been widely studied as biomembrane models and biosensor scaffolds. For technological applications, a major limitation of PSLBs composed of fluid lipids is that the bilayer structure is readily disrupted when exposed to chemical, mechanical, and thermal stresses. A number of asymmetric supported bilayer ...

N,N.-Ethylenebisstearimide (EBS) is one of the most commonlyused lubricants in the powder metallurgy (PM) industry in the sintering process. During sintering, the lubricated powder compacts are heat-treated to temperatures in excess of 1,200 °C thus fusing adjacent particles and yielding a part with improved mechanical strength. Delubrication commonly is achieved in the ...

N,N.-Ethylenebisstearimide (EBS) is one of the most commonlyused lubricants in the powder metallurgy (PM) industry in the sintering process. During sintering, the lubricated powder compacts are heat-treated to temperatures in excess of 1,200 �C thus fusing adjacent particles and yielding a part with improved mechanical strength. Delubrication commonly is achieved in the ...

In this study, we report the application of synchrotron radiation nanoprobe techniques to the structural analysis of pyramidal defects in Mg doped GaN. A combination of fluorescence mapping with spectroscopic techniques enabled us to examine not only the elemental nature but also their crystallographic orientation on the submicron scale. Our observations provide strong ...

The structure of oxygen-implanted silicon (dose -7.3 x 10/sup 16/cm/sup -2/) has been studied by transmission electron microscopy (TEM). The as-implanted material exhibited four structurally different layers: defect-free monocrystalline silicon, amorphous silicon, monocrystalline silicon with a high defect density, and the perfect ...

Microstructural, ?(13)C isotope and C/N ratio investigations were conducted on excavated material from the black Younger Dryas boundary in Lommel, Belgium, aiming for a characterisation of the carbon content and structures. Cubic diamond nanoparticles are found in large numbers. The larger ones with diameters around or above 10 nm often exhibit single or multiple twins. The ...

Microstructural, ?¹³C isotope and C/N ratio investigations were conducted on excavated material from the black Younger Dryas boundary in Lommel, Belgium, aiming for a characterisation of the carbon content and structures. Cubic diamond nanoparticles are found in large numbers. The larger ones with diameters around or above 10�nm often exhibit single or ...

Eddy current scanning (ECS) has been used to screen niobium sheets to avoid defective material being used in costly cavity fabrication. The evaluation criterion of this quality control tool is not well understood. Past surface studies showed some features were shallow enough to be removed by chemical etching. The remaining features were identified to be small number of deeper inclusions, but ...

We present a comprehensive study of the energetics and magnetic interactions in 3d transition metal doped ZnO clusters by ab-initio density functional calculations. We find an important evidence that the charge state of the dopant transition element located at the surface of the cluster is different from that expected in the bulk and has a crucial impact on their magnetic properties. In addition, ...

The polarization-preserving property of photonic crystals (PhCs) is combined to the superior extraction efficiency of embedded PhCs to enhance polarized light emission in m-plane GaN light-emitting diodes. As guided modes in m-plane GaN are mostly polarized along the a-direction (Evec ?avec ), their efficient extraction is achieved by one-dimensional embedded PhCs also aligned ...

A GaAs defect-free epitaxial layer has been grown on Si via a Ge concentration graded SiGe on insulator (SGOI) for application in high channel-mobility metal-oxide-semiconductor field effect transistor. The SGOI layer, 42 nm thick, serves as the compliant and intermediate buffer to reduce the lattice and thermal expansion mismatches between Si and GaAs. A modified two-step Ge ...

Fabricating defect-free mask blanks remains a major "show-stopper" for adoption of EUV lithography. One promising approach to alleviate this problem is reticle floorplanning with the goal of minimizing the design impact of buried defects. In this work, we propose a simulated annealing based gridded floorplanner for single project reticles that minimizes the design impact of ...

We discuss the present state-of-the-art concerning the growth mechanism, optical luminescence and electrical properties for GaN nanowires grown with catalyst-free molecular beam epitaxy. These nanowires are essentially defect-free and display long photoluminescence lifetimes and carrier mobilities relative to epitaxially grown GaN films. The exclusion of crystalline defects ...

Quality of care has become a focal point in healthcare. Hospitals and health systems continue to produce care that varies in quality. This leads to customer dissatisfaction as well as inefficient processes and output. As a result, administrators face a challenge to improve the quality of care in their organizations. One way to address quality improvement is to use various quality management ...

We performed low temperature (77 K) scanning tunneling microscopy (STM) and spectroscopy (STS) on the polar Zn-terminated ZnO(0001) surface [1]. STM and STS data show that the surface electronic structure strongly depends on the local morphology : we observe a narrow bandgap and surface states in the flat regions, and, in the defective surface regions, a wide bandgap without ...

Defects in photonic crystals are local regions in which the translational symmetry is broken. The same definition can be applied to photonic quasicrystals except in this case the symmetry is the 2pi/n rotational symmetry, where n is the rotational fold number. In this context, if no such defects are present, the structure is called "defect-free". Even ...

Surfaces having well-defined morphologies like periodic arrays of dots or lines, promise useful applications. Magnetic nanodots of Co and Fe-alloys are useful in patterned magnetic recording media. Well controlled grain size and surface area of nanostructured TiO2 are useful to develop efficient photocatalysts. However, there is a continuing need to develop techniques to make such surfaces in a ...

... which will permit the development of a general, low temperature process for obtaining oriented, defect free single crystal semiconductor films on ...

The diffusion of backside depositions of transition metals during rapid thermal annealing and the resulting frontside defect formation in silicon has been investigated. We have investigated the effect of nickel, copper, and gold on defect formation in silicon employing the rapid thermal processing (RTP) scheme. Treatment by RTP induces haze in the silicon wafer frontside when its backside is ...

Using density functional theory, we have theoretically studied sidewall functionalization of carbon nanotubes (CNT) with a nucleophilic organic carbene, dipyridyl imidazolidene (DPI). When compared to the dissociated system, formation of the adduct from defect-free (5,5) tube and the DPI is weakly exothermic. However, introduction of (5,7,7,5) defect or nitrogen doping at the ...

Structural defect-free GaPN and InGaPN layers were grown on a Si (100) substrate. Light emitting diodes (LEDs) and Si metaloxide-semiconductor field effect transistors (MOSFETs), which are elemental devices for optoelectronic integrated circuits(OEICs), were monolithically integrated in a single chip with a Si layer and an InGaPN/GaPN double ...

VPI-5 transforms to AlPO{sub 4}-8 under mild thermal treatment (100{degree}C, 18 hrs). HRTEM micrographs, oriented normal to the c axis, show extensive defect-free regions in VPI-5, while slip planes normal to the c axis are found in AlPO{sub 4}-8. Analysis of the HRTEM data, in conjunction with infrared and thermal analysis, adsorption studies and x-ray powder diffraction, ...

VPI-5 transforms to AlPO(sub 4)-8 under mild thermal treatment (100 C, 18 hrs). High resolution transmission electron microscopy (HRTEM) micrographs, oriented normal to the c axis, show extensive defect-free regions in VPI-5, while slip planes normal to the c axis are found in AlPO(sub 4)-8. Analysis of the HRTEM data, in conjunction with infrared and thermal analysis, ...

In this study, an approach combining ion cutting and selective chemical etch for the transfer of high crystalline-quality III-V layers on SiO{sub 2}/Si substrate has been investigated. This layer transfer scheme takes advantage of the ion-cutting process by conserving III-V substrates for reuse and simultaneously improving the transferred layer quality and surface condition without using chemical ...

In this study, an approach combining ion cutting and selective chemical etch for the transfer of high crystalline-quality III-V layers on SiO2/Si substrate has been investigated. This layer transfer scheme takes advantage of the ion-cutting process by conserving III-V substrates for reuse and simultaneously improving the transferred layer quality and surface condition without using chemical and ...

Selective area epitaxy (SAE) of InGaN quantum wells on GaN micropyramids were grown by using metalorganic chemical vapor deposition (MOCVD). The pattern prepared for the SAE was fabricated by the deposition of 300 nm SiO2 film on n-type GaN substrate by using plasma enhanced chemical vapor deposition (PECVD) and followed by photolithography. The grown micropyramid structures ...

Zinc blende structure GaAs/AlGaAs core-multishell nanowires (NWs) are grown on a GaAs(111) B substrate by a two-temperature process using an Au-catalyzed vapor-liquid-solid mechanism and metal organic chemical vapor deposition, respectively. Defect-free radial heterostructure NWs are formed. It can be concluded that the NWs are grown with the main ...

Macroscopic ferroelectric polarization switching, similar to other first order phase transitions, is controlled by nucleation centers. Despite 50 years of extensive theoretical and experimental effort, the microstructural origins of the Landauer paradox, i.e. the experimentally observed low values of coercive fields in ferroelectrics corresponding to implausibly large nucleation activation ...

The zero-temperature energies and equilibrium volume expansions of point-defect free asymmetrical grain boundaries (GBs) involving the four densest planes in fcc bicrystals (with some higher-index plane on the other side of the interface) have been determined using an embedded-atom-method potential fitted to Au. It is found that the two asymmetrical tilt ...

We present a method for characterizing avalanche photodiode (APD) photon-counting detector efficiency as a function of active area. Various shallow-junction silicon APDs having a novel active area were manufactured and tested. We show that cylindrical and checkquerboard-shaped active areas have dark counts two orders of magnitude lower than standard circular devices with an equivalent active area. ...

Density functional perturbation theory, combined with quasi-harmonic approximation theory and the Debye theory, has been used to calculate the thermal conductivity of the double-perovskite perovskite slab�rocksalt layer oxide compounds L2SrAl2O7 (L = La, Nd, Sm, Eu, Gd, and Dy), a promising class of high-temperature thermal insulators. The predicted properties are compared with experimental data ...

Development of the CdS/Cu/sub 2/S cell has focused on the planar junction design with an enhanced open circuit voltage. Various techniques have been tried in an attempt to improve the short circuit current. The maximum achieved is approx. 22 mA/cm/sup 2/ compared to approx. 25 mA/cm/sup 2/ for the traditional solution reaction cell. The highest efficiency ...

Computer simulations reveal how photoinduced chemical reactions can be exploited to create long-range order in binary and ternary polymeric materials. The process is initiated by shining a spatially uniform light over a photosensitive AB binary blend, which thereby undergoes both a reversible chemical reaction and phase separation. We then introduce a well-collimated, higher intensity light ...

Ultra-high performance concrete (UHPC) is relatively a new generation of concretes optimized at the nano and micro-scales to provide superior mechanical and durability properties compared to conventional and high performance concretes. Improvements in UHPC are achieved through: limiting the water-to-cementitious materials ratio (i.e., w/cm ? 0.20), optimizing particle packing, ...

The past ~10 years have witnessed revolutionary breakthroughs both in synthesis of quantum dots (leading to nearly monodispersed, defect-free nanostructures) and in characterization of such systems, revealing ultra narrow spectroscopic lines of <1 meV width, exposing new intriguing effects, such as multiple exciton generation, fine-structure splitting, ...

The more difficult part of developing a membrane reactor was making a membrane with suitable permselectivity. Since both the ammonia and H[sub 2]S decomposition reactions produce H[sub 2], we want a membrane that selectively permeates hydrogen. We have taken the approach of coating a substrate that has fine pores (a microfilter or ultrafilter) with a completely dense layer and then (except for ...

The more difficult part of developing a membrane reactor was making a membrane with suitable permselectivity. Since both the ammonia and H{sub 2}S decomposition reactions produce H{sub 2}, we want a membrane that selectively permeates hydrogen. We have taken the approach of coating a substrate that has fine pores (a microfilter or ultrafilter) with a completely dense layer and then (except for ...

The mechanical properties of materials and particularly the strength are greatly affected by the presence of defects; therefore, the theoretical strength (?10% of the Young's modulus) is not generally achievable for macroscopic objects. On the contrary, nanotubes, which are almost defect-free, should achieve the theoretical strength ...

Directed polymer self-assembly which combines lithographically defined substrates and self-assembled polymers has been considered as a potential candidate to extend conventional lithography techniques. Self-assembled block copolymer domains can multiply the spatial frequency and improve pattern quality of the underlying resist prepattern. Lamella-forming PS-b-PMMA is spin-cast on patterned ...

An unsupervised novelty detection method for automatic flaw segmentation in textile materials that has no need of any defect-free references or a training stage is presented in this paper. The algorithm is based on the structural feature extraction of the weave repeat from the Fourier transform of the sample image. These features are used to define a set ...

A description of the physisorption and subsequent chemisorption of water on silica glass surfaces is presented that combines electronic structure calculations with classical molecular dynamics simulations. The method associates the strength of the physisorption sites with the gradient of the electrostatic potential, and the chemical reactivity with the chemical hardness of the ...

... These assessment theories will assist the engineers to achieve a ... STRUCTURAL PROPERTIES, DYNAMICS, MATHEMATICAL MODELS, THEORY. ...

The pulsed magnetron sputtering of transparent conductive oxide (TCO) films from powder targets is a promising technique, which produces films with dense columnar, defect-free structures and optical and electrical properties comparable to other deposition techniques. The targets are formed from loosely packed oxide powder blends, and no additional ...

The microstructure of interface engineered ramp-edge Josephson junctions in YBCO has been studied by transmission electron microscopy (TEM). The junctions are distinctly different from the structures found in heterophase SNS junctions. This structural difference can be directly related to the improved electrical properties of interface engineered ...

Methane and diamond are common materials with well-known, but extremely different properties. Fundamental, compelling questions then arise: with sp^3 bound carbon molecules/clusters, at what sizes do diamond-like properties emerge? Pure, defect-free, perfectly hydrogen-terminated diamondoids, from �0.5 nm to �1 nm, bridge the gap between molecules and nanoparticles. ...

Transmission electron microscopy was applied to cross-sectioned samples to study surface morphology, sample polarity and defect distribution in bulk GaN samples doped with Mg. These crystals were grown from a Ga melt under high hydrostatic pressure of Nitrogen. It was shown that the types of defects and their distribution along the c-axis depends strongly on sample polarity. Based on this finding ...

Coupling the imprint mold structure having a self-assembled monolayer (SAM) and a buffer oxide layer (BOL) with a poly(vinyl alcohol) (PVA) resin is investigated for thermal nanoimprint lithography on flexible substrates. The mold structure is SAM/BOL/Cr. Among the buffer oxides tested (SiO2, Al2O3, HfO2), SiO2 results in the most hydrophobic character at ...

Nanotechnology is in continuous evolution leading to production of quasi-one dimensional (Q1D) structures in a variety of morphologies: nanowires, nanotubes, nanobelts, nanorods, nanorings, hierarchical structures. In particular, metal oxides represent an appealing category of materials with properties from metals to semiconductors and covering practically ...

We develop a dimensionless heat transfer model to analyze pulsed thermography data for non-destructive testing (NDT) of materials. Simulated thermographic sequences are used in order to evaluate the performance of the inspection technique. Also, we inspect organic and inorganic samples, including a layered plate and two dental pieces, in search of internal defects and ...

Growth of graphene on copper (100) single crystals by chemical vapor deposition has been accomplished. The atomic structure of the graphene overlayer was studied using scanning tunneling microscopy. A detailed analysis of moire? superstructures present in the graphene topography reveals that growth occurs in a variety of orientations over the square atomic lattice of the ...

Numerical modeling studies were carried out for the design and performance evaluation of an eddy current probe for superconducting quantum interference device (SQUID) based noncontacting electromagnetic nondestructive testing. The probe utilizes high-Tc SQUID from electromagnetic interference and to focus magnetic flux due to the eddy current excitation coil into the object under test (OUT). This ...

In this work, we demonstrate a novel approach for the transfer of Si layers onto handle wafers, induced by plasma hydrogenation. In the conventional ion-cut process, hydrogen ion implantation is used to initiate layer delamination at a desired depth, which leads to ion damage in the transferred layer. In this study, we investigated the use of plasma hydrogenation to achieve ...

Production of hydrogen by water splitting using solar energy is one of the long sought goals of hydrogen economy. Approximately 33% of solar radiation is emitted as high energy photons while the remaining 67% consists of primarily thermal energy. Utilization of both thermal and photonic energies within the solar spectrum is essential for achieving water splitting at high ...

Reversible photocontrol over the disorder-to-order transition (DOT) of block copolymers can be used to fabricate defect-free, long-range ordered nanomaterials over macroscopic distances by ``photo-combing'' the microdomains. Here, we randomly copolymerized anthracene functionalities in a ``dilute'' way with 2-hydroxyethyl methacrylate as the middle block, forming deuterated ...

Defect free masks remain one of the most significant challenges facing the commercialization of extreme ultraviolet (EUV) lithography. Progress on this front requires high-performance wavelength-specific metrology of EUV masks, including high-resolution and aerial-image microscopy performed near the 13.5?nm wavelength. Arguably the most cost-effective and ...

A lithography system in which the mask or reticle, which usually carries the pattern to be printed onto a substrate, is replaced by a programmable array of binary (i.e. on/off) light valves or switches which can be programmed to replicate a portion of the pattern each time an illuminating light source is flashed. The pattern of light produced by the programmable array is imaged onto a lithographic ...

A lithography system in which the mask or reticle, which usually carries the pattern to be printed onto a substrate, is replaced by a programmable array of binary (i.e. on/off) light valves or switches which can be programmed to replicate a portion of the pattern each time an illuminating light source is flashed. The pattern of light produced by the programmable array is imaged onto a lithographic ...

This paper discusses the self-assembled growth of In(Ga)As/GaAs quantum dots by metal-organic chemical vapor deposition and their application to diode lasers and integrated opto-electronic devices. After an extensive study of the growth parameters high densities (3-4�1010cm-2) of defect free quantum dots have been achieved and ground ...

The possibility of using x-ray radiographic imaging for detecting intenal defects in apples has been investigated. Four hundred to seven hundred each of five Washington State cultivars [Red and Golden Delicious (RD< GD), Fuji (FJ), Granny Smith (GS) and Braeburn (BR)], both defect free and with assorted internal defects (bruises, senescence browning, ...

The objectives of the second year of the program are to define a material composition and composite architecture that enable the oxygen flux and stability targets to be obtained in high-pressure flux tests. Composite technology will be developed to enable the production of high-quality, defect free membranes of a thickness that allows the oxygen flux ...

EUV mask blanks are fabricated by depositing a reflective Mo/Si multilayer film onto super-polished substrates. Localized defects in this thin film coating can significantly perturb the reflected field and produce errors in the printed image. Ideally one would want to manufacture defect-free mask blanks; however, this may be very difficult to achieve in ...

The atomic scale ordering and properties of cubic silicon carbide thin film surfaces are investigated by room and high temperature scanning tunneling microscopy. In this review, I focus on the Si-terminated ?-SiC(100) surfaces only. Self-formation of Si atomic lines and dimer vacancy chains on the ?-SiC(100) surface is taking place at the phase transition between the 3�2 (Si rich) and c(4�2) ...

larger areas of defect free silicon carbide (SiC), progressive coalescence must occur when adjoining cantilevers merge. The progressive coalescence is ...

In this ultra-vacuum environment, defect-free thin-film layers of gallium arsenide and other semiconductor materials can be grown. ...

Millimeter-sized single crystals of C60 were grown by sublimation of C60 powder in a vacuum for 6-24

process for aluminum alloys, producing virtually defect free welds with improved mechanical properties as compared to conventional fusion welding. Lockheed ...

... defect-free films of various chemically-selective polymers (see ... transport across the film will be dominated by Knudsen diffusion in these ...

... room temperature, and also in water at 37 ... ideally smooth, defect-free surfaces were synthesized ... the differences in geometry and surface morphology ...

... Abstract : Friction stir welding (FSW) is a solid state ... the rotating pin deforms (ie 'stirs') the locally ... a high integrity defect-free weld, process variables ...

A new class of composite zeolite membranes and synthesis techniques therefor has been invented. These membranes are essentially defect-free, and exhibit large levels of transmembrane flux and of chemical and isotopic selectivity.

Jun 16, 2011 � Surface displacement and strain maps revealed nonuniform strain distributions in seemingly defect-free fiber regions. ...

areas and high fiber volume areas (Figure. 13a,b). This significant variation ... frame and stringer bond lines were defect free (Figure 21). ...

Recent advances in the comprehension of the growth dynamics of colloidal crystal films opens the door to conscious design of experiments aiming at fabricating lattices in which the density of intrinsic defects is minimized. Since such imperfections have a dramatic effect on scattered light of wavelength smaller than the lattice constant, the evaluation of the experimental optical response at those ...

Undoped ZnO films were deposited using pulsed laser deposition technique on Si and glass substrates in different O2 partial pressures (ranging from 10(-5) mbar to 3 mbar) and substrate temperatures. When the substrate temperature is 500 degrees C and O2 partial pressure (pp) approximately 3 mbar, randomly oriented ZnO hexagons were observed on glass substrate, whereas, dense ZnO hexagonal rod like ...

Compression testing of micro-pillars has recently been of great interest to the small-scale mechanics community. Previous compression tests on single crystal Mo alloy micro-pillars produced by directional solidification of eutectic alloys showed that as-grown pillars yield at strengths close to the theoretical strength while pre-strained pillars yield at considerably lower stresses. In addition, ...

Conjugated materials offer the revolutionary prospect of producing semiconductor devices at low cost. The best to date discotics are built around the coronene unit and possess six fold symmetry. In the discotic phase six fold symmetric molecules stack with an average azimuthal twist of 30 deg, whereas the angle which would lead to the greatest electronic coupling and hence highest charge mobility ...

We propose to develop an inorganic metal-metal composite membrane to study reforming of liquid hydrocarbons and methanol by equilibrium shift in membrane-reactor configuration, viewed as fuel processor. Based on our current understanding and experience in the Pd-ceramic composite membrane, we propose to further develop this membrane to a Pd and Pd-Ag alloy membrane on microporous stainless steel ...

An effective method for the 3D porous scaffold design of human tissue is presented based on a hybrid method of distance field and triply periodic minimal surface (TPMS). By the creative application of traditional distance field algorithm into the Boolean operations of the anatomical model and TPMS-based unit cell library, an almost defects free porous ...

Highly ordered Ag nanocluster structures have been grown on pre-patterned amorphous SiO(2) surfaces by oblique angle physical vapor deposition at room temperature. Despite the small undulation of the rippled surface, the stripe-like Ag nanoclusters are very pronounced, reproducible and well separated. Computer modeling of the growth has been performed with a lattice-based ...

Highly ordered Ag nanocluster structures have been grown on pre-patterned amorphous SiO2 surfaces by oblique angle physical vapor deposition at room temperature. Despite the small undulation of the rippled surface, the stripe-like Ag nanoclusters are very pronounced, reproducible and well separated. Computer modeling of the growth has been performed with a lattice-based ...

Results are summarized of a fairly detailed study by high-resolution electron microscopy and electron diffraction of the high-temperature superconductor YBa/sub 2/Cu/sub 3/O/sub 7-delta/. Data from the perfect structure for (100), (110), and (001) zones indicate that the material has an oxygen-deficient perovskite structure as previously reported from ...

Materials with nanoscale features have new or improved properties compared to bulk materials. These properties depend on the composition, size, and shape of the material, and include high specific strength and modulus, low melting point, high electrical and thermal conductivity, a large surface area to volume ratio, nearly defect-free structure, magnetic ...

Pushing the limits of optical lithography by immersion technology requires ever smaller feature sizes on the reticle. At the same time the k1-factor will be shifted close to the theoretical limit, e.g. the OPC structures on the reticle become very aggressive. For the mask shop it is essential to manufacture defect free masks. The ...

The origin of intragrain defects in polycrystalline silicon films grown by ion-assisted deposition (IAD) on aluminum-induced crystallization seed layers on glass is investigated. The microstructure of these polycrystalline Si films is bimodal, with near defect-free regions of (001) orientation along the growth direction and highly defective regions containing smaller grains of ...

We present a new method to automatically segment local defects in a woven fabric that does not require any additional defect-free reference for comparison. Firstly, the structural features of the repetition pattern of the minimal weave repeat are extracted from the Fourier spectrum of the sample under inspection. The corresponding peaks are automatically ...

Nanostructured zinc oxide thin films were prepared by the oxidation of nanostructured zinc films deposited on glass substrates by thermal evaporation of metallic zinc in an atmosphere of nitrogen. The films were oxidized at different temperatures. X-ray diffraction was used to study the structural transformations of the films with oxidation temperature. Atomic force microscopy ...

The authors have studied the effects of intense X-ray irradiation on the structure of amorphous Si films. The films were obtained by either physical vapor deposition or by implantation of high energy ions into crystalline Si. They were exposed to different total doses of synchrotron X-rays. From the EXAFS and EXELFS measurements they find that an exposure to X-rays increases ...

Vertically well-aligned ZnO nanoridge, nanorod, nanorod-nanowall junction, and nanotip arrays have been successfully synthesized on Si (1 0 0) substrates using a pulsed laser deposition prepared ZnO film as seed layer by thermal evaporation method. Experimental results illustrated that the growth of different morphologies of ZnO nanostructures was strongly dependent upon substrate temperature. ...

We demonstrate defect-free and well-aligned self-assembly of cylindrical microdomains in block copolymer thin films on chemically-patterned substrates in arbitrarily large areas. Poly(styrene-b-methyl methacrylate) (PS-PMMA) with weight average molecular weight and weight fraction of PS being 6.7x10^3 and 0.69, respectively, was spin coated on chemically nano-patterned ...

The specific locations of the anions�nitrogen and oxygen�in the crystallographic sites are not known in the spinel-type gallium oxonitride. We report here on an indirect method for determining the specific location of the light elements N and O in a defect spinel-structured gallium oxonitride, Ga2.79O3.05N0.76. The locations of elements that are adjacent in the periodic ...

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), a biodegradable polyester, was electrospun to form defect-free fibers with high surface-area-to-volume ratio for skin regeneration. Several parameters such as solvent ratio, polymer concentration, applied voltage, flow rate, and tip-to-target distance were optimized to achieve ...

Infrared absorption of atomic and molecular vibrations in solids can be affected by electronic contributions through non-adiabatic interactions, such as the Fano effect. Typically, the infrared-absorption lineshapes are modified, or infrared-forbidden modes are detectable as a modulation of the electronic absorption. In contrast to such known phenomena, we report here the observation of a ...

Infrared absorption of atomic and molecular vibrations in solids can be affected by electronic contributions through non-adiabatic interactions, such as the Fano effect. Typically, the infrared-absorption lineshapes are modified, or infrared-forbidden modes are detectable as a modulation of the electronic absorption. In contrast to such known phenomena, we report here the observation of a ...

Development of technology for fabrication of thin-film temperature sensors on turbine blades that would remain adherent and at the same time function accurately under operating conditions was studied. The sensor system, essentially a thin-film thermocouple, consists of a multilayered coating structure where the critical aspects include adherence and purity of the layers, ...

Systematic studies of as-grown MnAs films deposited by molecular-beam epitaxy on GaAs(001) and GaAs(113)A reveal that their magnetic properties and, in particular, their saturation magnetization are determined by the phase separation into stripes of ferromagnetic {alpha}-MnAs and paramagnetic {beta}-MnAs. Using a specific saturation magnetization M{sub S}{sup *}, which refers to the actual volume ...

By means of scanning tunneling microscopy, Auger spectroscopy, and density-functional theory, we have identified a different strain-relaxation mechanism taking place in ultrathin CaO films grown on Mo(001). Whereas CaO films are amorphous at low growth temperature due to the substantial lattice mismatch with the support, a crystalline phase develops upon annealing to 1000 K. This phase is ...

The purpose of this work is to assess the feasibility of a homogeneous�or defect-free�initiation mechanism for high energetic materials in which initiation is a direct consequence of the heterogeneity of crystal plasticity at the subgrain scale. In order to assess the feasibility of these mechanisms, we develop a multiscale model that explicitly accounts for three scales: ...

The zero-temperature energies and equilibrium volume expansions of point-defect free grain boundaries (GBs) on the two densest planes of fcc copper, bcc molybdenum and cubic-diamond silicon have been determined, using an Embedded-Atom-Method potential for Cu, a Finnis-Sinclair potential for Mo, and the Stillinger-Weber potential for Si. It is found that in ...

A method for preparing a silicon-on-insulator material having a relatively defect-free Si overlayer involves the implanting of oxygen ions within a silicon body and the interruption of the oxygen-implanting step to implant Si ions within the silicon body. The implanting of the oxygen ions develops an oxide layer beneath the surface of the silicon body, and the Si ions ...

V-4Cr-4Ti alloy is selected as the structure material for the first wall/blanket in a fusion power reactor. A systematic study was conducted to develop a laser welding procedure for fabrication of vanadium alloy for the first wall/blanket systems. A 1.6 kW pulsed Nd:YAG laser with fiber optic beam delivery was used to carry out the bead-on-plate welding on 4 mm thick V-4Cr-4Ti ...

Low-temperature scanning tunneling microscopy and spectroscopy have been employed to analyze the local electronic structure of the (111) surface of a ceria thin film grown on Ru(0001). On pristine, defect-free oxide terraces, the empty 4f states of Ce(4+) ions appear as the only spectral feature inside the 6 eV oxide band gap. In contrast, occupied states ...

Most indentation studies to date on crystalline germanium (c-Ge) and related covalent semiconductors have been carried out on pristine defect-free material. This paper addresses the paucity of studies on imperfect crystalline materials by exploring the impact of defects generated by ion implantation, prior to contact damage, upon the mechanical properties of c-Ge. Implantation ...

Studies in the last decade suggest that microwave energy may have a unique ability to influence chemical processes. These include chemical and materials syntheses as well as separations. Specifically, recent studies have documented a significantly reduced time for fabricating zeolites, mixed oxide and mesoporous molecular sieves by employing microwave energy. In many cases, microwave syntheses ...

Transparent, translucent, and opaque regions of high-purity bulk SiC, produced by CVD, have been characterized for physical properties as well as microstructure and chemical purity to correlate degree of transparency with other material characteristics. A good correlation was obtained between SiC vis-a-vis IR transmission and its microstructure. The transparent material is highly oriented toward ...

Inorganic mesoporous membranes showed potential for water purification and desalinization by nanofiltration. In this work, a composite mesoporous inorganic membrane was synthesized with a two layer structure. The supporting layer was a macroporous alpha-Al 2O3 substrate prepared with the colloidal filtration technique. The functional layer was a mesoporous gamma-alumina thin ...

We use density functional theory to investigate the influence of surface vacancies on the surface stability of a stoichiometric freestanding LaAlO3 (001) thin film. Defect-free three- and five-unit-cell-thick LaAlO3 (001) thin films show macroscopic electric fields of 0.28 and 0.22 V/�, respectively. The built-in electric field is sufficiently strong for the ...

Artificial scaffolds for growing cells can have a wide range of applications including wound coverings, supports in tissue cultures, drug delivery, and organ and tissue transplantation. Tissue engineering is a promising field which may resolve current problems with transplantation, such as rejection by the immune system and scarcity of donors. One approach to tissue engineering utilizes a ...

Single-walled carbon nanotubes have shown a wealth of quantum transport phenomena thus far. Defect-free, unperturbed single-walled carbon nanotubes with well behaved or tunable metal contacts are important for probing the intrinsic electrical properties of nanotubes. Meeting these conditions experimentally is non-trivial owing to numerous disorder and randomizing factors. Here ...

In the defense community, certain uranium-alloy components have been manufactured by methods which generate large quantities of uranium bearing waste. Our estimates show that these components can be fabricated by vapor deposition and reduce waste generation by more than an order of magnitude. We present results from a series of uranium-alloy vapor deposition tests designed to produce samples of ...

It is shown that far- and near-field effects, which are similar to those arising in transmission through finite-thickness photonic crystals (PCs) with structural defects, can be obtained in the conventional defect-free dielectric square-lattice PCs. Multiple narrow peaks of total transmission can appear within a frequency range, where the noncircular ...

The first damage-free top-down fabrication processes for a two-dimensional array of 7 nm GaAs nanodiscs was developed by using ferritin (a protein which includes a 7 nm diameter iron core) bio-templates and neutral beam etching. The photoluminescence of GaAs etched with a neutral beam clearly revealed that the processes could accomplish defect-free etching for GaAs. In the ...

Diluted magnetic semiconductors (DMS), the essential materials for semiconductor spintronics, show a variety of complex properties, e.g., defect-mediated (ferro/antiferro)magnetic interactions and the disorder leading to magnetic percolation effects. Using the ab-initio Korringa-Kohn-Rostoker-Coherent-Potential-Approximation, the magnetic pair exchange parameters of a Heisenberg model have been ...

We report a method to predict the frequency dependence of coercive fields in ferroelectric films. The deduction of this method as well as the analysis are based on investigations of intrinsic switching kinetics of high-quality, single-crystal-like, epitaxial Pb(Zr{sub 0.2}Ti{sub 0.8})O{sub 3} thin films with extended defect-free structures. The newly ...

To enable plastic deformation during nanoindentation of an initially defect-free crystal, it is necessary first to produce dislocations. While it is now widely accepted that the nucleation of the first dislocations occurs at the start of the pop-in event frequently observed in experiments, it is unclear how these initial dislocations multiply during the early stages of plastic ...

Quantum dots (QDs) have great potential in optical fiber communication applications were widely recognized. The structure of molecular beam epitaxy (MBE) grew InAsN QDs were investigated by transmission electron microscopy (TEM) and measured their optical properties by photoluminescence (PL). TEM images show that the InAsN QDs are irregular or oval shaped. Some of the InAsN ...

The development of aeronautical and space propulsion systems structures technology is the mission of the Structures Division. The technology required to achieve reliable, high-performance, lightweight structures needed for aerospace propulsion is among th...

... MECHANICS IN THE USSR FOR 50 YEARS: ACHIEVEMENTS AND PROSPECTS,. ... structural mechanics of rod systems and the theory of elasticity ...

... to achieve slewing maneuvers for rapid retargeting and precision alignment of structural components supporting optical system components. ...

... achieved and maintained. Forest Structure Resulting from �Wildlife Forestry Silviculture� Contact: Daniel Twedt a...

While the stable control of such flexible structures as limber spacecraft is easily achieved through

... the space exterior to the structure's wall clearing uniform widths parallel to the walls of the structure. Thest -',iclsions are independent of roof ...

... The structure consists of a bowtie antenna mounted over the surface of a HIGR The proposed structure was intended to achieve a resonant ...

... ACOUSTIC TESTING OF STRUCTURES AT ELEVATED TEMPERATURES IS DISCUSSED, INCLUDING TECHNIQUES FOR ACHIEVING HIGHER ...