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Sample records for film bulk acoustic

  1. Recent developments of film bulk acoustic resonators

    NASA Astrophysics Data System (ADS)

    Gao, Junning; Liu, Guorong; Li, Jie; Li, Guoqiang

    2016-06-01

    Film bulk acoustic wave resonator (FBAR) experienced skyrocketing development in the past 15 years, owing to the explosive development of mobile communication. It stands out in acoustic filters mainly because of high quality factor, which enables low insertion loss and sharp roll off. Except for the massive application in wireless communication, FBARs are also promising sensors because of the high sensitivity and readily integration ability to miniaturize circuits. On the ground of summarizing FBAR’s application in wireless communication as filters and in sensors including electronic nose, bio field, and pressure sensing, this paper review the main challenges of each application faced. The number of filters installed in the mobile phone has being grown explosively, which leads to overcrowded bands and put harsh requirements on component size and power consumption control for each unit. Data flow and rate are becoming increasingly demanding as well. This paper discusses three promising technical strategies addressing these issues. Among which coupled resonator filter is given intense attention because it is able to vigorously reduce the filter size by stacking two or more resonators together, and it is a great technique to increase data flow and rate. Temperature compensation methods are discussed considering their vital influence on frequency stability. Finally, materials improvement and novel materials exploration for band width modulation, tunable band acquisition, and quality factor improvement are discussed. The authors appeal attention of the academic society to bring AlN epitaxial thin film into the FBAR fabrication and have proposed a configuration to implement this idea.

  2. Ferroelectric film bulk acoustic wave resonators for liquid viscosity sensing

    NASA Astrophysics Data System (ADS)

    Vorobiev, A.; Gevorgian, S.

    2013-08-01

    A concept of accurate liquid viscosity sensing, using bulk acoustic wave (BAW) resonators, is proposed. The proposed BAW resonators use thin ferroelectric films with the dc field induced piezoelectric effect allowing for generation of pure longitudinal acoustic waves in the thickness excitation mode. This makes it possible to utilize exclusively shear liquid particle displacement at the resonator side walls and, therefore, accurate viscosity evaluation. The BAW resonators with the dc field induced piezoelectric effect in 0.67BiFeO3-0.33BaTiO3 ferroelectric films are fabricated and their liquid viscosity sensing properties are characterized. The resonator response is analyzed using simple model of a harmonic oscillator damped by a viscous force. It is shown that the resonator Q-factor is inversely proportional to the square root of the viscosity-density product. The viscosity measurement resolution is estimated to be as high as 0.005 mPa.s, which is 0.5% of the water viscosity.

  3. Simulation and fabrication of thin film bulk acoustic wave resonator

    NASA Astrophysics Data System (ADS)

    Xixi, Han; Yi, Ou; Zhigang, Li; Wen, Ou; Dapeng, Chen; Tianchun, Ye

    2016-07-01

    In this paper, we present the simulation and fabrication of a thin film bulk acoustic resonator (FBAR). In order to improve the accuracy of simulation, an improved Mason model was introduced to design the resonator by taking the coupling effect between electrode and substrate into consideration. The resonators were fabricated by the eight inch CMOS process, and the measurements show that the improved Mason model is more accurate than a simple Mason model. The Q s (Q at series resonance), Q p (Q at parallel resonance), Q max and k t 2 of the FBAR were measured to be 695, 814, 1049, and 7.01% respectively, showing better performance than previous reports. Project supported by the National Natural Science Foundation of China (Nos. 61274119, 61306141, 61335008) and the Natural Science Foundation of Jiangsu Province (No. BK20131099).

  4. Quantitative Determination of Lateral Mode Dispersion in Film Bulk Acoustic Resonators through Laser Acoustic Imaging

    SciTech Connect

    Ken Telschow; John D. Larson III

    2006-10-01

    Film Bulk Acoustic Resonators are useful for many signal processing applications. Detailed knowledge of their operation properties are needed to optimize their design for specific applications. The finite size of these resonators precludes their use in single acoustic modes; rather, multiple wave modes, such as, lateral wave modes are always excited concurrently. In order to determine the contributions of these modes, we have been using a newly developed full-field laser acoustic imaging approach to directly measure their amplitude and phase throughout the resonator. This paper describes new results comparing modeling of both elastic and piezoelectric effects in the active material with imaging measurement of all excited modes. Fourier transformation of the acoustic amplitude and phase displacement images provides a quantitative determination of excited mode amplitude and wavenumber at any frequency. Images combined at several frequencies form a direct visualization of lateral mode excitation and dispersion for the device under test allowing mode identification and comparison with predicted operational properties. Discussion and analysis are presented for modes near the first longitudinal thickness resonance (~900 MHz) in an AlN thin film resonator. Plate wave modeling, taking account of material crystalline orientation, elastic and piezoelectric properties and overlayer metallic films, will be discussed in relation to direct image measurements.

  5. Protein-modified shear mode film bulk acoustic resonator for bio-sensing applications

    NASA Astrophysics Data System (ADS)

    Wang, Jingjing; Liu, Weihui; Xu, Yan; Chen, Da; Li, Dehua; Zhang, Luyin

    2014-09-01

    In this paper, we present a shear mode film bulk acoustic biosensor based on micro-electromechanical technology. The film bulk acoustic biosensor is a diaphragmatic structure consisting of a lateral field excited ZnO piezoelectric film piezoelectric stack built on an Si3N4 membrane. The device works at near 1.6 GHz with Q factors of 579 in water and 428 in glycerol. A frequency shift of 5.4 MHz and a small decline in the amplitude are found for the measurements in glycerol compared with those in water because of the viscous damping derived from the adjacent glycerol. For bio-sensing demonstration, the resonator was modified with biotin molecule to detect protein-ligand interactions in real-time and in situ. The resonant frequency of the biotin-modified device drops rapidly and gradually reaches equilibrium when exposed to the streptavidin solution due to the biotin-streptavidin interaction. The proposed film bulk acoustic biosensor shows promising applications for disease diagnostics, prognosis, and drug discovery.

  6. Streptavidin Modified ZnO Film Bulk Acoustic Resonator for Detection of Tumor Marker Mucin 1

    NASA Astrophysics Data System (ADS)

    Zheng, Dan; Guo, Peng; Xiong, Juan; Wang, Shengfu

    2016-09-01

    A ZnO-based film bulk acoustic resonator has been fabricated using a magnetron sputtering technology, which was employed as a biosensor for detection of mucin 1. The resonant frequency of the thin-film bulk acoustic resonator was located near at 1503.3 MHz. The average electromechanical coupling factor {K}_{eff}^2 and quality factor Q were 2.39 % and 224, respectively. Using the specific binding system of avidin-biotin, the streptavidin was self-assembled on the top gold electrode as the sensitive layer to indirectly test the MUC1 molecules. The resonant frequency of the biosensor decreases in response to the mass loading in range of 20-500 nM. The sensor modified with the streptavidin exhibits a high sensitivity of 4642.6 Hz/nM and a good selectivity.

  7. Sensitivity study of multilayer thin-film bulk acoustic resonator for mass sensor application

    NASA Astrophysics Data System (ADS)

    Liu, Haiqiang; Li, Fang; Qin, Lifeng; Wang, Qing-Ming

    2016-10-01

    The sensitivity of multilayer thin-film bulk acoustic resonators (MTFBARs) used as mass sensors is investigated. MTFBAR sensors with the structure of a mass-sensitive layer/electrode layer/piezo layer/electrode layer were used. Two methods, one using electric impedance and the other displacement, were adopted for the determination of sensitivity. Simulation results show that the two methods agree well, and the characteristic acoustic impedance and thickness of the non-piezo layers strongly affect mass sensitivity. It was found that high acoustic impedance in the non-piezo layer is not helpful for sensitivity improvement. Sensitivity is improved by choosing an appropriate thickness for the low acoustic impedance non-piezo layer, and the maximum sensitivity can be obtained by choosing suitable thickness combinations for the layers. Moreover, it was found that MTFBAR quality factor and sensitivity are simultaneously improved by adopting a high-quality-factor non-piezo layer with low acoustic impedance for an air working environment, whereas a balance between quality factor and sensitivity is found through optimization of the non-piezo layers for a water working environment. These results can be used for the design and application of MTFBAR mass sensors.

  8. Micro-electromechanical film bulk acoustic sensor for plasma and whole blood coagulation monitoring.

    PubMed

    Chen, Da; Song, Shuren; Ma, Jilong; Zhang, Zhen; Wang, Peng; Liu, Weihui; Guo, Qiuquan

    2017-05-15

    Monitoring blood coagulation is an important issue in the surgeries and the treatment of cardiovascular diseases. In this work, we reported a novel strategy for the blood coagulation monitoring based on a micro-electromechanical film bulk acoustic resonator. The resonator was excited by a lateral electric field and operated under the shear mode with a frequency of 1.9GHz. According to the apparent step-ladder curves of the frequency response to the change of blood viscoelasticity, the coagulation time (prothrombin time) and the coagulation kinetics were measured with the sample consumption of only 1μl. The procoagulant activity of thromboplastin and the anticoagulant effect of heparin on the blood coagulation process were illustrated exemplarily. The measured prothrombin times showed a good linear correlation with R(2)=0.99969 and a consistency with the coefficient of variation less than 5% compared with the commercial coagulometer. The proposed film bulk acoustic sensor, which has the advantages of small size, light weight, low cost, simple operation and little sample consumption, is a promising device for miniaturized, online and automated analytical system for routine diagnostics of hemostatic status and personal health monitoring.

  9. Long thickness-extensional waves in thin film bulk acoustic wave filters affected by interdigital electrodes.

    PubMed

    Liu, Jing; Du, Jianke; Wang, Ji; Yang, Jiashi

    2017-03-01

    We studied free vibrations of thin-film bulk acoustic wave filters with interdigital electrodes theoretically using the scalar differential equations by Tiersten and Stevens. The filters are made from AlN or ZnO films on Si substrates with ground and driving electrodes. They operate with thickness-extensional modes. The basic vibration characteristics including resonant frequencies and mode shapes were obtained. Their dependence on various geometric parameters was examined. It was found that for properly design filters there exist trapped modes whose vibrations are strong in regions with a driving electrode and decay away from the electrode edges. These trapped modes are essentially long plate thickness-extensional modes modulated by the electrode fingers. The number of trapped modes is sensitive to the geometric parameters.

  10. 3.4 GHz composite thin film bulk acoustic wave resonator for miniaturized atomic clocks

    NASA Astrophysics Data System (ADS)

    Artieda, Alvaro; Muralt, Paul

    2011-06-01

    Triple layer SiO2/AlN/SiO2 composite thin film bulk acoustic wave resonators (TFBARs) were studied for applications in atomic clocks. The TFBAR's were tuned to 3.4 GHz, corresponding to half the hyperfine splitting of the ground state of rubidium 87Rb atoms. The quality factor (Q) was equal to 2300 and the temperature coefficient of the resonance frequency fr amounted to 1.5 ppm/K. A figure of merit Qfr of ˜ 0.8 × 1013 Hz and a thickness mode coupling factor of 1% were reached. Such figures are ideal for frequency sources in an oscillator circuit that tracks the optical signal in atomic clocks.

  11. 3.4 GHz composite thin film bulk acoustic wave resonator for miniaturized atomic clocks

    SciTech Connect

    Artieda, Alvaro; Muralt, Paul

    2011-06-27

    Triple layer SiO{sub 2}/AlN/SiO{sub 2} composite thin film bulk acoustic wave resonators (TFBARs) were studied for applications in atomic clocks. The TFBAR's were tuned to 3.4 GHz, corresponding to half the hyperfine splitting of the ground state of rubidium {sup 87}Rb atoms. The quality factor (Q) was equal to 2300 and the temperature coefficient of the resonance frequency f{sub r} amounted to 1.5 ppm/K. A figure of merit Qf{sub r} of {approx} 0.8 x 10{sup 13} Hz and a thickness mode coupling factor of 1% were reached. Such figures are ideal for frequency sources in an oscillator circuit that tracks the optical signal in atomic clocks.

  12. A lateral field excited ZnO film bulk acoustic wave sensor working in viscous environments

    NASA Astrophysics Data System (ADS)

    Chen, Da; Wang, Jingjing; Xu, Yan; Li, Dehua; Zhang, Liuyin; Liu, Weihui

    2013-09-01

    We present a lateral field excited ZnO film bulk acoustic resonator (FBAR) operated in pure-shear mode and analyze its performances in viscous liquids. The electrodes of the device are located on the film surface and normal to the c-axis of the ZnO film. The proposed device works near 1.44 GHz with a Q-factor up to 360 in air and 310 in water, which are higher than those of the quasi-shear thickness field excited FBAR. The resonant frequency is decreased with the increasing square root of the product of the viscosity and density with a linear dependence in the viscosity below 148.7 mPa s. The mass sensitivity of 670 Hz cm2 ng-1 was measured by monitoring the frequency change during the volatilization of saline solution loaded on the resonator. In addition, the levels of the noise and the mass resolutions were measured in various viscous environments. The proposed device yields the mass resolution of 670 Hz cm2 ng-1 and the high mass resolution of 0.06 ng cm-2. These results indicated that the lateral field excited ZnO FBAR had superior sensitivity for the bio-sensing applications in viscous biological liquids.

  13. Real-time monitoring of human blood clotting using a lateral excited film bulk acoustic resonator

    NASA Astrophysics Data System (ADS)

    Chen, Da; Wang, Jingjng; Wang, Peng; Guo, Qiuquan; Zhang, Zhen; Ma, Jilong

    2017-04-01

    Frequent assay of hemostatic status is an essential issue for the millions of patients using anticoagulant drugs. In this paper, we presented a micro-fabricated film bulk acoustic sensor for the real-time monitoring of blood clotting and the measurement of hemostatic parameters. The device was made of an Au/ZnO/Si3N4 film stack and excited by a lateral electric field. It operated under a shear mode resonance with the frequency of 1.42 GHz and had a quality factor of 342 in human blood. During the clotting process of blood, the resonant frequency decreased along with the change of blood viscosity and showed an apparent step-ladder curve, revealing the sequential clotting stages. An important hemostatic parameter, prothrombin time, was quantitatively determined from the frequency response for different dilutions of the blood samples. The effect of a typical anticoagulant drug (heparin) on the prothrombin time was exemplarily shown. The proposed sensor displayed a good consistency and clinical comparability with the standard coagulometric methods. Thanks to the availability of direct digital signals, excellent potentials of miniaturization and integration, the proposed sensor has promising application for point-of-care coagulation technologies.

  14. High-Q AlN/SiO2 symmetric composite thin film bulk acoustic wave resonators.

    PubMed

    Artieda, Alvaro; Muralt, Paul

    2008-11-01

    High-Q, bulk acoustic wave composite resonators based on a symmetric layer sequence of SiO(2)-AlN-SiO(2) sandwiched between electrodes have been developed. Acoustic isolation was achieved by means of deep silicon etching to obtain membrane type thin film bulk acoustic wave resonators (TFBARs). Three different device versions were investigated. The SiO(2) film thicknesses were varied (0 nm, 70 nm, 310 nm, and 770 nm) while the piezoelectric AlN film had a constant thickness of 1.2 microm. The sputter-deposited AlN film grown on the amorphous, sputter-deposited SiO(2) layer exhibited a d(33,f) of 4.0 pm/V. Experimental results of quality factors (Q) and coupling coefficients (k(t)(2)) are in agreement with finite element calculations. A Q of 2000 is observed for the first harmonic of the 310 nm oxide devices. The most intense resonance of the 770 nm oxide device is the third harmonic reaching Q factors of 1450. The temperature drift reveals the impact of the SiO(2) layers, which is more pronounced on the first harmonic, reducing the TCF to 4 ppm/K for the 3rd harmonic of the 310 nm oxide devices.

  15. Sensing characteristics of pure-shear film bulk acoustic resonator in viscous liquids

    NASA Astrophysics Data System (ADS)

    Chen, Da; Song, Shuren; Zhang, Dexue; Wang, Peng; Liu, Weihui

    2017-03-01

    We presented a pure-shear film bulk acoustic resonator (FBAR) and investigated its sensing characteristics in viscous liquids. In the resonator, the electrodes were located on the surface of c-axis-oriented AlN film to generate the lateral electric field and excite the shear acoustic resonance. Compared with the typical quasi-shear film bulk acoustic resonator based on inclined c-axis-oriented AlN or ZnO piezoelectric film, the proposed device exhibits significantly higher Q-factors and a notably improved detection limit, particularly in water and viscous liquids. The frequency shifts show a linear dependency on the square root of the product of the liquid viscosity and density of the glycerol solution in the viscosity range of 1-5 mPaṡs. Furthermore, we measured the mass sensitivity through real-time monitoring of the frequency change during the volatilization process of the loaded saline solutions. The proposed device shows the mass sensitivity of 465 Hzṡcm2/ng and the mass resolutions of 0.17 ng/cm2 in air, 0.25 ng/cm2 in water and 2.08 ng/cm2 in 50% glycerol solution, respectively. The obtained results clearly indicate that the proposed device is capable of using in liquid phase detection with high sensitivity requirements.

  16. Large electromechanical coupling factor film bulk acoustic resonator with X-cut LiNbO3 layer transfer

    NASA Astrophysics Data System (ADS)

    Pijolat, M.; Loubriat, S.; Queste, S.; Mercier, D.; Reinhardt, A.; Defaÿ, E.; Deguet, C.; Clavelier, L.; Moriceau, H.; Aïd, M.; Ballandras, S.

    2009-11-01

    As layer transfer techniques have been notably improved in the past years, lithium niobate (LiNbO3) appears as a candidate for the next generation of ultrawide band radio frequency (rf) filters. Depending on the crystalline orientation, LiNbO3 can achieve electromechanical coupling factors Kt2 more than six times larger than those of sputtered aluminum nitride films. In this letter, a process based on direct bonding, grinding, polishing, and deep reactive ion etching is proposed to fabricate a single crystal LiNbO3 film bulk acoustic resonator. From the fabricated test vehicles, Kt2 of 43% is measured confirming the values predicted by theoretical computations.

  17. Highly sensitive detection of organophosphorus pesticides by acetylcholinesterase-coated thin film bulk acoustic resonator mass-loading sensor.

    PubMed

    Chen, Da; Wang, Jingjing; Xu, Yan; Li, Dehua; Zhang, Luyin; Li, Zhaoxin

    2013-03-15

    An acetylcholinesterase-coated thin film bulk acoustic resonator has been developed for the detection of organophosphorus pesticides. The thin film bulk acoustic resonator acts as a robust mass-sensitive transducer for bio-sensing. This device works in thickness shear mode with a resonance at 1.97 GHz. The detection is based on the inhibitory effects of organophosphorus compounds on the enzymatic activity of the acetylcholinesterase immobilized on one of the faces of the acoustic resonator. The enzyme reaction in the substrate solution and the inhibitory effect is observed are real time by measuring the frequency shift. The presence of organophosphorus pesticides can be detected from the diminution of the frequency shift compared with the levels found in their absence. The device exhibits linear responses, good reproducibility, simple operation, portability and a low detection limit of 5.3×10(-11) M for paraoxon. The detection results of organophosphorus pesticide residues in practical samples show that the proposed sensor has the feasibility and sensing accuracy comparable to gas chromatography.

  18. Dual-mode thin film bulk acoustic wave resonators for parallel sensing of temperature and mass loading.

    PubMed

    García-Gancedo, L; Pedrós, J; Zhao, X B; Ashley, G M; Flewitt, A J; Milne, W I; Ford, C J B; Lu, J R; Luo, J K

    2012-01-01

    Thin film bulk acoustic wave resonator (FBAR) devices supporting simultaneously multiple resonance modes have been designed for gravimetric sensing. The mechanism for dual-mode generation within a single device has been discussed, and theoretical calculations based on finite element analysis allowed the fabrication of FBARs whose resonance modes have opposite reactions to temperature changes; one of the modes exhibiting a positive frequency shift for a rise of temperature whilst the other mode exhibits a negative shift. Both modes exhibit negative frequency shift for a mass load and hence by monitoring simultaneously both modes it is possible to distinguish whether a change in the resonance frequency is due to a mass load or temperature variation (or a combination of both), avoiding false positive/negative responses in gravimetric sensing without the need of additional reference devices or complex electronics.

  19. Materials for Bulk Acoustic Resonators and Filters

    NASA Astrophysics Data System (ADS)

    Loebl, Hans-Peter

    2003-03-01

    Highly selective solidly mounted bulk acoustic wave (BAW) band pass filters are suited for mobile and wireless systems in the GHz frequency range between 0.8 and 10 GHz. Electro-acoustic thin film BAW resonators are the building blocks these BAW filters. Piezoelectric materials used in these resonators include mainly AlN or ZnO which can be deposited by dedicated thin film sputter deposition techniques. Using these piezo-electric materials and using suited materials for the acoustic Bragg reflector, BAW resonators with high quality factors can be fabricated. The achievable filter bandwidth is approximately 4Alternatively, also ferroelectric thin films might be used to achieve higher coupling coefficient and thus filter bandwidth. BAW resonators and filters have been designed and fabricated on 6" Silicon and glass wafers. Results are presented for resonators and filters operating between 1.95 and 8 GHz. The talk will give an overview of the material aspects which are important for BAW devices. It will be shown that modeling of the resonator and filter response using 1D electro-acoustic simulation (1,2) which includes losses is essential to extract acoustic and electrical material parameters. (1) Solidly Mounted Bulk Acoustic Wave Filters for the Ghz Frequency Range, H.P. Loebl, C. Metzmacher , D.N.Peligrad , R. Mauczok , M. Klee , W. Brand , R.F. Milsom , P.Lok , F.van Straten , A. Tuinhout , J.W.Lobeek, IEEE 2002 Ultrasonics Symposium Munich, October 2002. (2) Combined Acoustic-Electromagnetic Simulation Of Thin-Film Bulk Acoustic Wave Filters, R.F. Milsom, H-P. Löbl, D.N. Peligrad, J-W. Lobeek, A. Tuinhout, R. H. ten Dolle IEEE 2002 Ultrasonics Symposium Munich, October 2002.

  20. A film bulk acoustic resonator-based high-performance pressure sensor integrated with temperature control system

    NASA Astrophysics Data System (ADS)

    Zhang, Mengying; Zhao, Zhan; Du, Lidong; Fang, Zhen

    2017-04-01

    This paper presented a high-performance pressure sensor based on a film bulk acoustic resonator (FBAR). The support film of the FBAR chip was made of silicon nitride and the part under the resonator area was etched to enhance the sensitivity and improve the linearity of the pressure sensor. A micro resistor temperature sensor and a micro resistor heater were integrated in the chip to monitor and control the operating temperature. The sensor chip was fabricated, and packaged in an oscillator circuit for differential pressure detection. When the detected pressure ranged from  ‑100 hPa to 600 hPa, the sensitivity of the improved FBAR pressure sensor was  ‑0.967 kHz hPa‑1, namely  ‑0.69 ppm hPa‑1, which was 19% higher than that of existing sensors with a complete support film. The nonlinearity of the improved sensor was less than  ±0.35%, while that of the existing sensor was  ±5%. To eliminate measurement errors from humidity, the temperature control system integrated in the sensor chip controlled the temperature of the resonator up to 75 °C, with accuracy of  ±0.015 °C and power of 20 mW.

  1. Detection of DNA hybridisation in a diluted serum matrix by surface plasmon resonance and film bulk acoustic resonators.

    PubMed

    Auer, Sanna; Nirschl, Martin; Schreiter, Matthias; Vikholm-Lundin, Inger

    2011-05-01

    Nanomolar quantities of single-stranded DNA products ~100 nucleotides long can be detected in diluted 1% serum by surface plasmon resonance (SPR) and film bulk acoustic resonators (FBARs). We have used a novel FBAR sensor in parallel with SPR and obtained promising results with both the acoustic and the optical device. Oligonucleotides and a repellent lipoamide, Lipa-DEA, were allowed to assemble on the sensor chip surfaces for only 15 min by dispensing. Lipa-DEA surrounds the analyte-binding probes on the surface and effectively reduces the non-specific binding of bovine serum albumin and non-complementary strands. In a highly diluted serum matrix, the non-specific binding is, however, a hindrance, and the background response must be reduced. Nanomolar concentrations of short complementary oligos could be detected in buffer, whereas the response was too low to be measured in serum. DNA strands that are approximately 100 base pairs long at concentrations as low as 1-nM could be detected both in buffer and in 1% serum by both SPR and the FBAR resonator.

  2. Monolithic integrated system with an electrowetting-on-dielectric actuator and a film-bulk-acoustic-resonator sensor

    NASA Astrophysics Data System (ADS)

    Zhang, Menglun; Cui, Weiwei; Chen, Xuejiao; Wang, Chao; Pang, Wei; Duan, Xuexin; Zhang, Daihua; Zhang, Hao

    2015-02-01

    Although digital microfluidics has shown great potential in a wide range of applications, a lab-on-a-chip with integrated digital droplet actuators and powerful biochemical sensors is still lacking. To address the demand, a fully integrated chip with electrowetting-on-dielectric (EWOD) and a film bulk acoustic resonator (FBAR) sensor is introduced, where an EWOD actuator manipulates digital droplets and the FBAR sensor detects the presence of substances in the droplets, respectively. The piezoelectric layer of the FBAR sensor and the dielectric layer of the EWOD share the same aluminum nitride (AlN) thin film, which is a key factor to achieve the full integration of the two completely different devices. The liquid droplets are reliably managed by the EWOD actuator to sit on or move off the FBAR sensor precisely. Sessile drop experiments and limit of detection (LOD) experiments are carried out to characterize the EWOD actuator and the FBAR sensor, respectively. Taking advantage of the digital droplet operation, a ‘dry sensing mode’ of the FBAR sensor in the lab-on-a-chip microsystem is proposed, which has a much higher signal to noise ratio than the conventional ‘wet sensing mode’. Hg2+ droplets with various concentrations are transported and sensed to demonstrate the capability of the integrated system. The EWOD-FBAR chip is expected to play an important role in many complex lab-on-a-chip applications.

  3. Nitrogen [N]-incorporated ZnO piezoelectric thin films and their application for ultra-small film bulk acoustic wave resonator device fabrication

    SciTech Connect

    Lee, Eunju; Zhang Ruirui; Yoon, Giwan

    2011-10-01

    Nitrogen [N]-incorporated ZnO films with columnar grains of a preferred c-axis orientation were deposited on p-Si (100) wafers, using an RF magnetron sputter deposition technique. For the N incorporation into the ZnO films, an N{sub 2}O gas was used as a doping source and also various process conditions such as N{sub 2}O gas fraction and RF power were applied. Besides, some of the ZnO films were treated with the post annealing process. And then, the micro-structural characteristics of the N-incorporated ZnO films were investigated by a scanning electron microscope, an X-ray diffractometer, and an atomic force microscope techniques. Finally, employing the N-incorporated ZnO films, the solidly mounted resonator-type film bulk acoustic wave resonator devices were fabricated and their resonance characteristics were extracted. As a result, an excellent return loss (S{sub 11}) of- 63 dB was observed at{approx} 0.6 GHz, better than ever reported.

  4. UV sensing using film bulk acoustic resonators based on Au/n-ZnO/piezoelectric-ZnO/Al structure

    PubMed Central

    Bian, Xiaolei; Jin, Hao; Wang, Xiaozhi; Dong, Shurong; Chen, Guohao; Luo, J. K.; Deen, M. Jamal; Qi, Bensheng

    2015-01-01

    A new type of ultraviolet (UV) light sensor based on film bulk acoustic wave resonator (FBAR) is proposed. The new sensor uses gold and a thin n-type ZnO layer deposited on the top of piezoelectric layer of FBAR to form a Schottky barrier. The Schottky barrier's capacitance can be changed with UV light, resulting in an enhanced shift in the entire FBAR's resonant frequency. The fabricated UV sensor has a 50 nm thick n-ZnO semiconductor layer with a carrier concentration of ~ 1017 cm−3. A large frequency downshift is observed when UV light irradiates the FBAR. With 365 nm UV light of intensity 1.7 mW/cm2, the FBAR with n-ZnO/Au Schottky diode has 250 kHz frequency downshift, much larger than the 60 kHz frequency downshift in a conventional FBAR without the n-ZnO layer. The shift in the new FBAR's resonant frequency is due to the junction formed between Au and n-ZnO semiconductor and its properties changes with UV light. The experimental results are in agreement with the theoretical analysis using an equivalent circuit model of the new FBAR structure. PMID:25773146

  5. Longitudinal bulk acoustic mass sensor

    SciTech Connect

    Hales, J. H.; Teva, J.; Boisen, A.; Davis, Z. J.

    2009-07-20

    A polycrystalline silicon longitudinal bulk acoustic cantilever is fabricated and operated in air at 51 MHz. A mass sensitivity of 100 Hz/fg (1 fg=10{sup -15} g) is obtained from the preliminary experiments where a minute mass is deposited on the device by means of focused ion beam. The total noise in the currently applied measurement system allows for a minimum detectable mass of 0.5 fg in air.

  6. Longitudinal bulk acoustic mass sensor

    NASA Astrophysics Data System (ADS)

    Hales, J. H.; Teva, J.; Boisen, A.; Davis, Z. J.

    2009-07-01

    A polycrystalline silicon longitudinal bulk acoustic cantilever is fabricated and operated in air at 51 MHz. A mass sensitivity of 100 Hz/fg (1 fg=10-15 g) is obtained from the preliminary experiments where a minute mass is deposited on the device by means of focused ion beam. The total noise in the currently applied measurement system allows for a minimum detectable mass of 0.5 fg in air.

  7. Microfabricated bulk wave acoustic bandgap device

    DOEpatents

    Olsson, Roy H.; El-Kady, Ihab F.; McCormick, Frederick; Fleming, James G.; Fleming, Carol

    2010-06-08

    A microfabricated bulk wave acoustic bandgap device comprises a periodic two-dimensional array of scatterers embedded within the matrix material membrane, wherein the scatterer material has a density and/or elastic constant that is different than the matrix material and wherein the periodicity of the array causes destructive interference of the acoustic wave within an acoustic bandgap. The membrane can be suspended above a substrate by an air or vacuum gap to provide acoustic isolation from the substrate. The device can be fabricated using microelectromechanical systems (MEMS) technologies. Such microfabricated bulk wave phononic bandgap devices are useful for acoustic isolation in the ultrasonic, VHF, or UHF regime (i.e., frequencies of order 1 MHz to 10 GHz and higher, and lattice constants of order 100 .mu.m or less).

  8. Microfabricated bulk wave acoustic bandgap device

    DOEpatents

    Olsson, Roy H.; El-Kady, Ihab F.; McCormick, Frederick; Fleming, James G.; Fleming, legal representative, Carol

    2010-11-23

    A microfabricated bulk wave acoustic bandgap device comprises a periodic two-dimensional array of scatterers embedded within the matrix material membrane, wherein the scatterer material has a density and/or elastic constant that is different than the matrix material and wherein the periodicity of the array causes destructive interference of the acoustic wave within an acoustic bandgap. The membrane can be suspended above a substrate by an air or vacuum gap to provide acoustic isolation from the substrate. The device can be fabricated using microelectromechanical systems (MEMS) technologies. Such microfabricated bulk wave phononic bandgap devices are useful for acoustic isolation in the ultrasonic, VHF, or UHF regime (i.e., frequencies of order 1 MHz to 10 GHz and higher, and lattice constants of order 100 .mu.m or less).

  9. Investigation of Shallow Bulk Acoustic Waves

    DTIC Science & Technology

    1981-11-12

    with the theoretical calculation using equivalent circuit model. How- ever, the spurious bulk wave level at high frequencies is much lower than that of...effect of a metallic grating on SBAW devices on quartz. 7 A periodic metallic structure will support horizontal shear surface waves if the finger...We have extensively investigated shallow bulk acoustic waves in. terms of material aspects, transducer equivalent circuits and device dev-.iopment

  10. Effects of thermal annealing of W/SiO2 multilayer Bragg reflectors on resonance characteristics of film bulk acoustic resonator devices with cobalt electrodes

    NASA Astrophysics Data System (ADS)

    Yim, Munhyuk; Kim, Dong-Hyun; Chai, Dongkyu; Yoon, Giwan

    2004-05-01

    In this article, we present the thermal annealing effects of the W/SiO2 multilayer reflectors in ZnO-based film bulk acoustic resonator (FBAR) devices with cobalt (Co) electrodes in comparison with those with aluminum (Al) electrodes. Various thermal annealing conditions have been implemented on the W/SiO2 multilayer reflectors formed on p-type (100) silicon substrates. The resonance characteristics could be significantly improved due to the thermal annealing and were observed to depend strongly on the annealing conditions applied to the reflectors. Particularly, the FBAR devices with the W/SiO2 multilayer reflectors annealed at 400 °C/30 min have shown superior resonance characteristics in terms of return loss and quality factor. In addition, the use of Co electrodes has resulted in the further improvement of the resonance characteristics as compared with the Al electrodes. As a result, the combined use of both the thermal annealing and Co electrodes seems very useful to more effectively improve the resonance characteristics of the FBAR devices with the W/SiO2 multilayer reflectors. .

  11. Applications of surface acoustic and shallow bulk acoustic wave devices

    NASA Astrophysics Data System (ADS)

    Campbell, Colin K.

    1989-10-01

    Surface acoustic wave (SAW) device coverage includes delay lines and filters operating at selected frequencies in the range from about 10 MHz to 11 GHz; modeling with single-crystal piezoelectrics and layered structures; resonators and low-loss filters; comb filters and multiplexers; antenna duplexers; harmonic devices; chirp filters for pulse compression; coding with fixed and programmable transversal filters; Barker and quadraphase coding; adaptive filters; acoustic and acoustoelectric convolvers and correlators for radar, spread spectrum, and packet radio; acoustooptic processors for Bragg modulation and spectrum analysis; real-time Fourier-transform and cepstrum processors for radar and sonar; compressive receivers; Nyquist filters for microwave digital radio; clock-recovery filters for fiber communications; fixed-, tunable-, and multimode oscillators and frequency synthesizers; acoustic charge transport; and other SAW devices for signal processing on gallium arsenide. Shallow bulk acoustic wave device applications include gigahertz delay lines, surface-transverse-wave resonators employing energy-trapping gratings, and oscillators with enhanced performance and capability.

  12. Dual Mode Thin Film Bulk Acoustic Resonators (FBARs) Based on AlN, ZnO and GaN Films with Tilted c-Axis Orientation

    DTIC Science & Technology

    2010-01-01

    FBARs fabri - cation, and their thickness usually ranges from several mi- crometers down to tenth of micrometers, which results in high resonant...mentioned be- fore. Films with in-plane polarization have also been fabri - cated on certain substrate crystal such as tetragonal LiAlO2 100 for...dynamics, and cerebral aneurysm diseases ; his research work is also related to experimental and medical device design. Hongbin Cheng received his

  13. Porous silicon bulk acoustic wave resonator with integrated transducer

    PubMed Central

    2012-01-01

    We report that porous silicon acoustic Bragg reflectors and AlN-based transducers can be successfully combined and processed in a commercial solidly mounted resonator production line. The resulting device takes advantage of the unique acoustic properties of porous silicon in order to form a monolithically integrated bulk acoustic wave resonator. PMID:22776697

  14. Studies of acoustical properties of bulk porous flexible materials

    NASA Technical Reports Server (NTRS)

    Lambert, R. F.

    1984-01-01

    Acoustic prediction and measurement of bulk porous materials with flexible frames is investigated. The acoustic properties of Kevlar 29 are examined. Various acoustic tests are employed to determine impedance, sound wave propagation, and wave pressure equations for the highly porous fiber composites. The derivation of design equations and future research goals are included.

  15. Switchable and Tunable Ferroelectric Bulk Acoustic Wave Resonators and Filters

    NASA Astrophysics Data System (ADS)

    Saddik, George Nabih

    Ferroelectric materials such as barium titanate (BaTiO 3 or BTO), strontium titanate (SrTiO3 or STO), and their solid solution barium strontium titanate (BaxSr1-xTiO 3 or BST) have been under investigation for over 50 years. BTO, STO, and BST are high-k dielectric materials, with a field dependent permittivity and a perovskite crystal structure. At room temperature BTO is a ferroelectric with a ferroelectric to paraelectric transition temperature of about 116°C (Curie temperature), while STO has no ferroelectric phase. The formation of a solid solution between BTO and STO allows for the engineering of the Curie temperature; the Curie temperature decreses as the mole ratio of barium decreases. Extensive research went into understanding the properties of BST and developing RF circuits such as tunable capacitors, tunable matching networks, tunable filters, phase shifters and harmonic generators. BST tunable capacitors have always had anomalous resonances in the one port scattering parameter measurements, although they are very small they degrade the quality factor of the device, and research went into reducing these resonances as much as possible. The goal of this thesis is to investigate these anomalous resonances and exploit them into RF devices and circuits. Careful investigation showed that these resonances were field induced piezoelectric resonance. Piezoelectric materials such as AlN, ZnO, and PZT are used in many applications, such as resonators, and filters. Thin film bulk acoustic wave resonators (FBAR) have been in use by research and industry since the early 1980s, and in high volume production for cell phone duplexers since early 2000s. FBAR filters and duplexers have several advantages over surface acoustic wave (SAW) and ceramic devices such as high quality factors necessary for sharp filter skirts, small size, high performance, and ease of integration. There are two approaches to designing bulk acoustic wave resonators. The first is an FBAR where a

  16. Anisotropic diffraction of bulk acoustic wave beams in lithium niobate.

    PubMed

    Naumenko, Natalya F; Chizhikov, Sergey I; Molchanov, Vladimir Ya; Yushkov, Konstantin B

    2015-12-01

    The formalism of planar diffraction tensor was applied to the analysis of anisotropy of bulk acoustic wave diffraction and to build a full map of anisotropic diffractional coefficients for three bulk acoustic wave modes propagating in lithium niobate. For arbitrary propagation direction the diffractional coefficients derived allow estimation of ultrasonic beam divergence in far-field. Analysis of obtained data revealed that the maxima of acousto-optic figure of merit for anisotropic diffraction in the YZ plane correspond to moderate diffractional spreading of the beams exceeding isotropic diffraction 2-3 times.

  17. S-Band Shallow Bulk Acoustic Wave (SBAW) microwave source

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Techniques necessary to fabricate a high performance S-band microwave single source using state-of-the-art shallow bulk acoustic wave (SBAW) were explored. The bulk wave structures of the AlN/Al 2O3 were investigated for both the R plane and basal plane of sapphire. A 1.072 GHz SBAW delay line and oscillators were developed. A method of selecting and setting oscillator output frequency by selecting substrate orientation angle was also established.

  18. Bulk photoemission from metal films and nanoparticles

    SciTech Connect

    Ikhsanov, R Sh; Babicheva, V E; Protsenko, I E; Uskov, A V; Guzhva, M E

    2015-01-31

    Internal emission of photoelectrons from metal films and nanoparticles (nanowires and nanospheres) into a semiconductor matrix is studied theoretically by taking into account the jump of the effective electron mass at the metal – semiconductor interface and the cooling effect of hot electrons due to electron – electron collisions in the metal. The internal quantum efficiency of photoemission for the film and nanoparticles of two types (nanospheres and nanowires) is calculated. It is shown that the reduction of the effective mass of the electron during its transition from metal to semiconductor may lead to a significant (orders of magnitude and higher) decrease in the internal quantum efficiency of bulk photoemission. (nanostructures)

  19. Measured acoustic properties of variable and low density bulk absorbers

    NASA Technical Reports Server (NTRS)

    Dahl, M. D.; Rice, E. J.

    1985-01-01

    Experimental data were taken to determine the acoustic absorbing properties of uniform low density and layered variable density samples using a bulk absober with a perforated plate facing to hold the material in place. In the layered variable density case, the bulk absorber was packed such that the lowest density layer began at the surface of the sample and progressed to higher density layers deeper inside. The samples were placed in a rectangular duct and measurements were taken using the two microphone method. The data were used to calculate specific acoustic impedances and normal incidence absorption coefficients. Results showed that for uniform density samples the absorption coefficient at low frequencies decreased with increasing density and resonances occurred in the absorption coefficient curve at lower densities. These results were confirmed by a model for uniform density bulk absorbers. Results from layered variable density samples showed that low frequency absorption was the highest when the lowest density possible was packed in the first layer near the exposed surface. The layers of increasing density within the sample had the effect of damping the resonances.

  20. Magnetophonon oscillations caused by acoustic phonons in bulk conductors

    NASA Astrophysics Data System (ADS)

    Raichev, O. E.

    2016-09-01

    The interaction of electrons with acoustic phonons under a magnetic field leads to a remarkable kind of magnetophonon oscillation of transport coefficients, recently discovered in two-dimensional electron systems. The present study shows that similar oscillations exist in bulk conductors and provides a theory of this phenomenon for the case of spherical Fermi surfaces. The resonance peaks occur when the product of the Fermi surface diameter by the sound velocity is a multiple of the cyclotron frequency. Theoretical predictions may facilitate the experimental observation of the phenomenon.

  1. Optical find of hypersonic surface acoustic waves in bulk transparent materials

    NASA Astrophysics Data System (ADS)

    Jiménez Riobóo, Rafael J.; Sánchez-Sánchez, Alberto; Prieto, Carlos

    2016-07-01

    It is shown that direct information from surface acoustic waves (SAWs) of bulk transparent materials can be obtained by using Brillouin light scattering (BLS). The study of surface phonons by means of an optical spectroscopy such as BLS has been historically constrained to nontransparent and highly reflecting bulk and film samples or even to very thin films deposited on reflecting substrates. Probably due to its low signal and to the narrow window in experimental conditions, it was assumed for years that bulk transparent samples were not suited for Brillouin spectroscopy in order to get information on SAWs, negating this optical technique in the search for SAW properties. The reported experiments on transparent glasses and single crystals (cubic MgO and trigonal sapphire) prove that there is no intrinsic physical reason not to collect SAW propagation velocity data from transparent bulk samples and opens a challenge to apply the Brillouin spectroscopy in a wider scenario to obtain direct information, in a nondestructive and contactless way, about SAWs in bulk materials.

  2. Surface acoustic wave propagation in graphene film

    SciTech Connect

    Roshchupkin, Dmitry Plotitcyna, Olga; Matveev, Viktor; Kononenko, Oleg; Emelin, Evgenii; Irzhak, Dmitry; Ortega, Luc; Zizak, Ivo; Erko, Alexei; Tynyshtykbayev, Kurbangali; Insepov, Zinetula

    2015-09-14

    Surface acoustic wave (SAW) propagation in a graphene film on the surface of piezoelectric crystals was studied at the BESSY II synchrotron radiation source. Talbot effect enabled the visualization of the SAW propagation on the crystal surface with the graphene film in a real time mode, and high-resolution x-ray diffraction permitted the determination of the SAW amplitude in the graphene/piezoelectric crystal system. The influence of the SAW on the electrical properties of the graphene film was examined. It was shown that the changing of the SAW amplitude enables controlling the magnitude and direction of current in graphene film on the surface of piezoelectric crystals.

  3. Surface acoustic wave propagation in graphene film

    NASA Astrophysics Data System (ADS)

    Roshchupkin, Dmitry; Ortega, Luc; Zizak, Ivo; Plotitcyna, Olga; Matveev, Viktor; Kononenko, Oleg; Emelin, Evgenii; Erko, Alexei; Tynyshtykbayev, Kurbangali; Irzhak, Dmitry; Insepov, Zinetula

    2015-09-01

    Surface acoustic wave (SAW) propagation in a graphene film on the surface of piezoelectric crystals was studied at the BESSY II synchrotron radiation source. Talbot effect enabled the visualization of the SAW propagation on the crystal surface with the graphene film in a real time mode, and high-resolution x-ray diffraction permitted the determination of the SAW amplitude in the graphene/piezoelectric crystal system. The influence of the SAW on the electrical properties of the graphene film was examined. It was shown that the changing of the SAW amplitude enables controlling the magnitude and direction of current in graphene film on the surface of piezoelectric crystals.

  4. Excitation and propagation of shear-horizontal-type surface and bulk acoustic waves.

    PubMed

    Hashimoto, K Y; Yamaguchi, M

    2001-09-01

    This paper reviews the basic properties of shear-horizontal (SH)-type surface acoustic waves (SAWs) and bulk acoustic waves (BAWs). As one of the simplest cases, the structure supporting Bleustein-Gulyaev-Shimizu waves is considered, and their excitation and propagation are discussed from various view points. First, the formalism based on the complex integral theory is presented, where the surface is assumed to be covered with an infinitesimally thin metallic film, and it is shown how the excitation and propagation of SH-type waves are affected by the surface perturbation. Then, the analysis is extended to a periodic grating structure, and the behavior of SH-type SAWs under the grating structure is discussed. Finally, the origin of the leaky nature is explained.

  5. Opportunities for shear energy scaling in bulk acoustic wave resonators.

    PubMed

    Jose, Sumy; Hueting, Raymond J E

    2014-10-01

    An important energy loss contribution in bulk acoustic wave resonators is formed by so-called shear waves, which are transversal waves that propagate vertically through the devices with a horizontal motion. In this work, we report for the first time scaling of the shear-confined spots, i.e., spots containing a high concentration of shear wave displacement, controlled by the frame region width at the edge of the resonator. We also demonstrate a novel methodology to arrive at an optimum frame region width for spurious mode suppression and shear wave confinement. This methodology makes use of dispersion curves obtained from finite-element method (FEM) eigenfrequency simulations for arriving at an optimum frame region width. The frame region optimization is demonstrated for solidly mounted resonators employing several shear wave optimized reflector stacks. Finally, the FEM simulation results are compared with measurements for resonators with Ta2O5/ SiO2 stacks showing suppression of the spurious modes.

  6. Picosecond Acoustic Measurement of Anisotropic Properties of Thin Films

    SciTech Connect

    Perton, M.; Rossignol, C.; Chigarev, N.; Audoin, B.

    2007-03-21

    Properties of thin metallic films have been studied extensively by means of laser-picosecond ultrasonics. Generation of longitudinal and shear waves via thermoelastic mechanism and large source has been only demonstrated for waves vectors along the normal to the interface. However, such measurements cannot provide complete information about elastic properties of films. As it has been already shown for nanosecond ultrasonics, the knowledge of group or phase velocities in several directions for sources with small lateral size allows determining the stiffness tensor coefficients of a sample. The experimental set-up was prepared to obtain the thinnest size for the source to achieve acoustic diffraction. The identification of the stiffness tensor components, based on the inversion of the bulk waves phase velocities, is applied to signals simulated and experimentally recorded for a material with hexagonal properties. First estimation of stiffness tensor coefficients for thin metallic film 2.1 {mu}m has been performed.

  7. Acoustic phonon dynamics in thin-films of the topological insulator Bi2Se3

    NASA Astrophysics Data System (ADS)

    Glinka, Yuri D.; Babakiray, Sercan; Johnson, Trent A.; Holcomb, Mikel B.; Lederman, David

    2015-04-01

    Transient reflectivity traces measured for nanometer-sized films (6-40 nm) of the topological insulator Bi2Se3 revealed GHz-range oscillations driven within the relaxation of hot carriers photoexcited with ultrashort (˜100 fs) laser pulses of 1.51 eV photon energy. These oscillations have been suggested to result from acoustic phonon dynamics, including coherent longitudinal acoustic phonons in the form of standing acoustic waves. An increase of oscillation frequency from ˜35 to ˜70 GHz with decreasing film thickness from 40 to 15 nm was attributed to the interplay between two different regimes employing traveling-acoustic-waves for films thicker than 40 nm and the film bulk acoustic wave resonator (FBAWR) modes for films thinner than 40 nm. The amplitude of oscillations decays rapidly for films below 15 nm thick when the indirect intersurface coupling in Bi2Se3 films switches the FBAWR regime to that of the Lamb wave excitation. The frequency range of coherent longitudinal acoustic phonons is in good agreement with elastic properties of Bi2Se3.

  8. Mechanically robust microfluidics and bulk wave acoustics to sort microparticles

    NASA Astrophysics Data System (ADS)

    Dauson, Erin R.; Gregory, Kelvin B.; Greve, David W.; Healy, Gregory P.; Oppenheim, Irving J.

    2016-04-01

    Sorting microparticles (or cells, or bacteria) is significant for scientific, medical and industrial purposes. Research groups have used lithium niobate SAW devices to produce standing waves, and then to align microparticles at the node lines in polydimethylsiloxane (PDMS, silicone) microfluidic channels. The "tilted angle" (skewed) configuration is a recent breakthrough producing particle trajectories that cross multiple node lines, making it practical to sort particles. However, lithium niobate wafers and PDMS microfluidic channels are not mechanically robust. We demonstrate "tilted angle" microparticle sorting in novel devices that are robust, rapidly prototyped, and manufacturable. We form our microfluidic system in a rigid polymethyl methacrylate (PMMA, acrylic) prism, sandwiched by lead-zirconium-titanate (PZT) wafers, operating in through-thickness mode with inertial backing, that produce standing bulk waves. The overall configuration is compact and mechanically robust, and actuating PZT wafers in through-thickness mode is highly efficient. Moving to this novel configuration introduced new acoustics questions involving internal reflections, but we show experimental images confirming the intended nodal geometry. Microparticles in "tilted angle" devices display undulating trajectories, where deviation from the straight path increases with particle diameter and with excitation voltage to create the mechanism by which particles are sorted. We show a simplified analytical model by which a "phase space" is constructed to characterize effective particle sorting, and we compare our experimental data to the predictions from that simplified model; precise correlation is not expected and is not observed, but the important physical trends from the model are paralleled in the measured particle trajectories.

  9. Electro-acoustic sensors based on AlN thin film: possibilities and limitations

    NASA Astrophysics Data System (ADS)

    Wingqvist, Gunilla

    2011-06-01

    The non-ferroelectric polar wurtzite aluminium nitride (AlN) material has been shown to have potential for various sensor applications both utilizing the piezoelectric effect directly for pressure sensors or indirectly for acoustic sensing of various physical, chemical and biochemical sensor applications. Especially, sputter deposited AlN thin films have played a central role for successful development of the thin film electro-acoustic technology. The development has been primarily driven by one device - the thin film bulk acoustic resonator (FBAR or TFBAR), with its primary use for high frequency filter applications for the telecom industry. AlN has been the dominating choice for commercial application due to compatibility with the integrated circuit technology, low acoustic and dielectric losses, high acoustic velocity in combination with comparably high (but still for some applications limited) electromechanical coupling. Recently, increased piezoelectric properties (and also electromechanical coupling) in the AlN through the alloying with scandium nitride (ScN) have been identified both experimentally and theoretically. Inhere, the utilization of piezoelectricity in electro-acoustic sensing will be discussed together with expectation on acoustic FBAR sensor performance with variation in piezoelectric material properties in the parameter space around AlN due to alloying, in view of the ScxAl1-xN (0

  10. Effects on LDEF exposed copper film and bulk

    NASA Technical Reports Server (NTRS)

    Peters, Palmer N.; Gregory, John C.; Christl, Ligia C.; Raikar, Ganesh N.

    1991-01-01

    Two forms of copper were exposed to the Long Duration Exposure Facility (LDEF) Mission 1 environment: a copper film, initially 74.2 plus or minus 1.1 nm thick sputter coated on a fused silica flat and a bulk piece of oxygen-free, high conductivity (OFHC) copper. The optical density of the copper film changed from 1.33 to 0.70 where exposed, and the film thickness increased to 106.7 plus or minus 0.5 nm where exposed. The exposed area appears purple by reflection and green by transmission for the thin film and maroon color for the bulk copper piece. The exposed areas increased in thickness, but only increase in the thickness of the thin film sample could be readily measured. The increase in film thickness is consistent with the density changes occurring during conversion of copper to an oxide. However, we have not been able to confirm appreciable conversion to an oxide by x-ray diffraction studies. We have not yet subjected the sample to e-beams or more abusive investigations out of concern that the film might be modified.

  11. Effects on LDEF exposed copper film and bulk

    NASA Technical Reports Server (NTRS)

    Peters, Palmer N.; Gregory, John C.; Christl, Ligia C.; Raikar, Ganesh N.

    1992-01-01

    Two forms of copper were exposed to the Long Duration Exposure Facility (LDEF) Mission 1 environment: a copper film initially 74.2 plus or minus 1.1 nm thick sputter coated on a fused silical flat and a bulk piece of oxygen free, high conductivity (OFHC) copper. The optical density of the copper film changed from 1.33 to 0.70 where exposed and the film thickness increased to 106.7 plus or minus 0.5 nm where exposed. The exposed area appears purple by reflection and green by transmission for the thin film and maroon color for the bulk copper piece. The exposed areas increased in thickness, but only increase in the thickness of thin film samples could be readily measured. The increase in film thickness is consistent with the density changes occurring during conversion of copper to an oxide. However, we have not been able to confirm appreciable conversion to an oxide by x ray diffraction studies. We have not yet subjected the sample to e-beams or more abusive conditions out of concern that the film might be modified.

  12. Modulated exponential films generated by surface acoustic waves and their role in liquid wicking and aerosolization at a pinned drop

    NASA Astrophysics Data System (ADS)

    Taller, Daniel; Go, David B.; Chang, Hsueh-Chia

    2013-05-01

    The exponentially decaying acoustic pressure of scattered surface acoustic waves (SAWs) at the contact line of a liquid film pinned to filter paper is shown to sustain a high curvature conic tip with micron-sized modulations whose dimension grows exponentially from the tip. The large negative capillary pressure in the film, necessary for offsetting the large positive acoustic pressure at the contact line, also creates significant negative hydrodynamic pressure and robust wicking action through the paper. An asymptotic analysis of this intricate pressure matching between the quasistatic conic film and bulk drop shows that the necessary SAW power to pump liquid from the filter paper and aerosolize, expressed in terms of the acoustic pressure scaled by the drop capillary pressure, grows exponentially with respect to twice the acoustic decay constant multiplied by the drop length, with a universal preexponential coefficient. Global rapid aerosolization occurs at a SAW power twice as high, beyond which the wicking rate saturates.

  13. Modulated exponential films generated by surface acoustic waves and their role in liquid wicking and aerosolization at a pinned drop.

    PubMed

    Taller, Daniel; Go, David B; Chang, Hsueh-Chia

    2013-05-01

    The exponentially decaying acoustic pressure of scattered surface acoustic waves (SAWs) at the contact line of a liquid film pinned to filter paper is shown to sustain a high curvature conic tip with micron-sized modulations whose dimension grows exponentially from the tip. The large negative capillary pressure in the film, necessary for offsetting the large positive acoustic pressure at the contact line, also creates significant negative hydrodynamic pressure and robust wicking action through the paper. An asymptotic analysis of this intricate pressure matching between the quasistatic conic film and bulk drop shows that the necessary SAW power to pump liquid from the filter paper and aerosolize, expressed in terms of the acoustic pressure scaled by the drop capillary pressure, grows exponentially with respect to twice the acoustic decay constant multiplied by the drop length, with a universal preexponential coefficient. Global rapid aerosolization occurs at a SAW power twice as high, beyond which the wicking rate saturates.

  14. Thin Superconducting Film Characterization by Surface Acoustic Waves.

    DTIC Science & Technology

    2014-09-26

    NUMBER 2. GOVT ACCESSION NO. 3 RECIPIENT’S CA ALOG NUMBER ~~AFOSR TR -0 8 4. TITLE (and Subtitle) 5 TYPE OF REPORT & PERIOD COVERED Thin Superconducting ...thin film superconductor surface acoustic waves I SAW electron phonon interaction superconducting energy gap electron mean free path vortex...electrical resistivity and the attenuation of surface ,e J -acoustic waves (SAW) were measured in the superconducting state of a L granular lead film

  15. Acoustic phonon dynamics in thin-films of the topological insulator Bi{sub 2}Se{sub 3}

    SciTech Connect

    Glinka, Yuri D.; Babakiray, Sercan; Johnson, Trent A.; Holcomb, Mikel B.; Lederman, David

    2015-04-28

    Transient reflectivity traces measured for nanometer-sized films (6–40 nm) of the topological insulator Bi{sub 2}Se{sub 3} revealed GHz-range oscillations driven within the relaxation of hot carriers photoexcited with ultrashort (∼100 fs) laser pulses of 1.51 eV photon energy. These oscillations have been suggested to result from acoustic phonon dynamics, including coherent longitudinal acoustic phonons in the form of standing acoustic waves. An increase of oscillation frequency from ∼35 to ∼70 GHz with decreasing film thickness from 40 to 15 nm was attributed to the interplay between two different regimes employing traveling-acoustic-waves for films thicker than 40 nm and the film bulk acoustic wave resonator (FBAWR) modes for films thinner than 40 nm. The amplitude of oscillations decays rapidly for films below 15 nm thick when the indirect intersurface coupling in Bi{sub 2}Se{sub 3} films switches the FBAWR regime to that of the Lamb wave excitation. The frequency range of coherent longitudinal acoustic phonons is in good agreement with elastic properties of Bi{sub 2}Se{sub 3}.

  16. Transport and Magnetism in Bulk and Thin Film Strontium Titanate

    NASA Astrophysics Data System (ADS)

    Ambwani, Palak

    SrTiO3 is a wide band-gap perovskite oxide semiconductor that is widely investigated in the bulk form, due to its remarkable electronic properties. These properties arise from its quantum paraelectric nature which enables unique features, such as, a high-mobility low-density metallic state, quantum transport in an unusual limit, and the most dilute superconducting state thus reported. Recent advances in deposition of oxide thin films and heterostructures have further led to some remarkable observations, such as, the strain-enhancement of mobility in doped thin films of SrTiO3, and the presence of 2D electron gases at interfaces and in delta-doped layers. The presence of magnetic moments and their possible ordering, and the simultaneous observation of quantum oscillations and superconductivity, have been reported in these 2D electron gases. While magnetism has been observed in heterostructures of SrTiO3 , there have been limited reports on magnetism in bulk SrTiO3. The first part of this thesis (Chapter 3) discusses how circularly polarized light can induce an extremely long-lived magnetic moment in slightly oxygen-deficient but otherwise nominally pure SrTiO3-delta bulk crystals. These magnetic signals, which are induced at zero applied magnetic field and at low temperatures below ˜ 18 K, can be controlled in both magnitude and sign by means of the circular polarization and wavelength of sub-bandgap illumination (400-500 nm), and point to the existence of optically polarizable VO-related complexes in the forbidden gap of SrTiO 3-delta, rather than collective or long-range magnetic order. The methods used to detect optically induced magnetization are also discussed (Appendix A). The phenomenal progress reported in thin films and heterostructures of SrTiO3 has been possible only by precise control of stoichiometry and defect density in SrTiO3 using techniques such as oxide/LASER MBE or high-temperature PLD. The next part of the thesis (Chapter 4) demonstrates that

  17. Interface and bulk properties of HfO2 films

    NASA Astrophysics Data System (ADS)

    Biswas, Nivedita; Harris, Harlan; Choi, Kisik; Temkin, Henryk; Gangopadhyay, Shubhra

    2003-03-01

    HfO2 films of varying thickness were deposited on silicon and titanium by reactive electron beam evaporation. Metal gates of Titanium were deposited to form MIS and MIM structures. Capacitance-voltage and conductance-voltage measurements were performed to analyze the HfO2/Si interface and HfO2 bulk. For samples having thickness between 30 and 300 Å the C-V curves of the as-deposited samples were marked by charge leakage, huge hysteresis and frequency dispersion. However, annealing the sample in H2 ambient reduced charge leakage, hysteresis and the frequency dispersion of the C-V curves. A dielectric constant of the annealed films was calculated to be 17. The interface state density as calculated using the method of Nicollian and Brews was 2-3E10 cm-2eV-1 close to the midgap. To study the bulk properties, HfO2 films of thickness 2100 Å with platinum electrodes were deposited on silicon and titanium nitride. The C-V and G-V curves of both as-deposited and annealed samples were measured. Interface state density was found to be comparable to that of the thin samples. Thus the passivation of bulk and interface states with hydrogen annealing is independent of thickness. The gap state densities were found compatible with the observed hysteresis of the as-deposited ( 1E16-1E17 eV-1cm-3) and annealed sample (1E14-1E15eV-1cm-3).

  18. Extremely high Q-factor mechanical modes in quartz bulk acoustic wave resonators at millikelvin temperature

    SciTech Connect

    Goryachev, M.; Creedon, D. L.; Ivanov, E. N.; Tobar, M. E.; Galliou, S.; Bourquin, R.

    2014-12-04

    We demonstrate that Bulk Acoustic Wave (BAW) quartz resonator cooled down to millikelvin temperatures are excellent building blocks for hybrid quantum systems with extremely long coherence times. Two overtones of the longitudinal mode at frequencies of 15.6 and 65.4 MHz demonstrate a maximum f.Q product of 7.8×10{sup 16} Hz. With this result, the Q-factor in such devices near the quantum ground state can be four orders of magnitude better than previously attained in other mechanical systems. Tested quartz resonators possess the ultra low acoustic losses crucial for electromagnetic cooling to the phonon ground state.

  19. Acoustic Experiment to Measure the Bulk Viscosity of Near-Critical Xenon in Microgravity

    NASA Technical Reports Server (NTRS)

    Gillis, K. A.; Shinder, I.; Moldover, M. R.; Zimmerli, G. A.

    2002-01-01

    We plan a rigorous test of the theory of dynamic scaling by accurately measuring the bulk viscosity of xenon in microgravity 50 times closer to the critical temperature T(sub c) than previous experiments. The bulk viscosity zeta (or "second viscosity" or "dilational viscosity") will be determined by measuring the attenuation length of sound alpha lambda and also measuring the frequency-dependence of the speed of sound. For these measurements, we developed a unique Helmholtz resonator and specialized electro-acoustic transducers. We describe the resonator, the transducers, their performance on Earth, and their expected performance in microgravity.

  20. Label-free detection of protein-ligand interactions in real time using micromachined bulk acoustic resonators

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Pang, Wei; Marma, Mong S.; Lee, Chuang-Yuan; Kamal-Bahl, Sanat; Kim, Eun Sok; McKenna, Charles E.

    2010-03-01

    In this paper, we present a micromachined film bulk acoustic resonator (FBAR) to detect protein-ligand interactions in real-time. The surface of the FBAR device has a thin layer of gold deposited on it to immobilize thiol-modified biotin. The resonant frequency of the biotin modified FBAR was measured to decrease by 170 ppm when exposed to streptavidin solution with a concentration of 5×10-7 M, corresponding to an added mass of 120 pg on the FBAR surface due to the biotin-streptavidin interaction. Consequently, the biotin modified FBAR can be used to observe in real time the biotin-streptavidin interaction without the use of labeling or molecular tags. The FBAR can be used in a variety of protein-ligand systems, and be designed for testing in array formats to give high throughput screening for drug discovery.

  1. Acoustical performance of an electrostrictive polymer film loudspeaker

    PubMed

    Heydt; Pelrine; Joseph; Eckerle; Kornbluh

    2000-02-01

    A new type of loudspeaker that generates sound by means of the electrostrictive response of a thin polymer film is described. Electrostrictive polymer film (EPF) loudspeakers are constructed with inexpensive, lightweight materials and have a very low profile. The films are typically silicone and are coated with compliant electrodes to allow large film deformations. Acoustical frequency response measurements from 5 x 5 cm (planar dimensions) prototype EPF loudspeakers are presented. Measurements of harmonic distortion are also shown, along with results demonstrating reduced harmonic distortion achieved with square-root wave shaping. Applications of EPF loudspeakers include active noise control and general-purpose flat-panel loudspeakers.

  2. Progress on Acoustic Measurements of the Bulk Viscosity of Near-Critical Xenon (BVX)

    NASA Technical Reports Server (NTRS)

    Gillis, Keith A.; Shinder, Iosif I.; Moldover, Michael R.; Zimmerli, Gregory A.

    2004-01-01

    We plan to determine the bulk viscosity of xenon 10 times closer [in reduced temperature tau = (T-Tc)/Tc] to its liquid-vapor critical point than ever before. (Tc is the critical temperature.) To do so, we must measure the dispersion and attenuation of sound at frequencies 1/100 of those used previously. In general, sound attenuation has contributions from the bulk viscosity acting throughout the volume of the xenon as well as contributions from the thermal conductivity and the shear viscosity acting within thin thermoacoustic boundary layers at the interface between the xenon and the solid walls of the resonator. Thus, we can determine the bulk viscosity only when the boundary layer attenuation is small and well understood. We present a comparison of calculations and measurements of sound attenuation in the acoustic boundary layer of xenon near its liquid-vapor critical point.

  3. Crystalline state and acoustic properties of zinc oxide films

    SciTech Connect

    Kal'naya, G.I.; Pryadko, I.F.; Yarovoi, Yu.A.

    1988-08-01

    We study the effect of the crystalline state of zinc oxide films, prepared by magnetron sputtering, on the efficiency of SAW transducers based on the layered system textured ZnO film-interdigital transducer (IDT)-fused quartz substrate. The crystalline perfection of the ZnO films was studied by the x-ray method using a DRON-2.0 diffractometer. The acoustic properties of the layered system fused quartz substrate-IDT-zinc oxide film were evaluated based on the squared electromechanical coupling constant K/sup 2/ for strip filters. It was found that K/sup 2/ depends on the magnitude of the mechanical stresses. When zinc oxide films are deposited by the method of magnetron deposition on fused quartz substrates, depending on the process conditions limitations can arise on the rate of deposition owing to mechanical stresses, which significantly degrade the efficiency of SAW transducers based on them, in the ZnO films.

  4. Surface acoustic wave devices including Langmuir-Blodgett films (Review)

    NASA Astrophysics Data System (ADS)

    Plesskii, V. P.

    1991-06-01

    Recent theoretical and experimental research related to the use of Langmuir-Blodgett (LB) films in surface acoustic wave (SAW) devices is reviewed. The sensitivity of the different cuts of quartz and lithium niobate to inertial loading is investigated, and it is shown that some cuts in lithium niobate are twice as sensitive to mass loading than the commonly used YZ-cut. The large variety of organic compounds suitable for the production of LB films makes it possible to create SAW sensors reacting selectively to certain substances. The existing SAW sensors based on LB films are characterized by high sensitivity and fast response.

  5. Surface acoustic wave gas sensor based on film conductivity changes

    NASA Astrophysics Data System (ADS)

    Ricco, A. J.; Martin, S. J.; Zipperian, T. E.

    1985-12-01

    The first surfce acoustic wave (SAW) sensor that functions via changes in conductivity of a thin surface film is reported. A lead phthalocyanine (PbPc) thin film is deposted on the acoustic progagation path of a LiNbO3 SAW delay line, which serves as the feedback element of an oscillator circuit. Reaction with strongly oxidizing gases, in particular NO2, increases the conductivity of the PbPc film. Acoustoelectric coupling of the traveling electric potential wave associated with the SAW-to-charge carriers in the PbPc film slows the acoustic wave velocity, altering the oscillation frequency of the circuit. This sensor is about 1000 times more sensitive, in terms of the number of NO2 molecules that can be detected (10 to the 16th molecules/cu cm of PbPc film), than an identical SAW sensor functioning via mass loading would be. Sensitivity to a few ppm of NO2 in N2 has been demonstrated.

  6. Surface acoustic wave gas sensor based on film conductivity changes

    NASA Astrophysics Data System (ADS)

    Ricco, A. J.; Martin, S. J.; Zipperian, T. E.

    The first surface acoustic wave (SAW) sensor that functions via changes in conductivity of a thin surface film is reported. A lead phthalocyanine (PbPc) thin film is deposited on the acoustic propagation path of a LiNbO3 SAW delay line, which serves as the feedback element of an oscillator circuit. Reaction with strongly oxidizing gases, in particular NO2, increases the conductivity of the PbPc film. Acoustoelectic coupling of the traveling electric potential wave associated with the SAW-to-charge carriers in the PbPc film slows the acoustic wave velocity, altering the oscillation frequency of the circuit. This sensor is about 1000 times more sensitive, in terms of the number of NO2 molecules that can be detected (10 to the 16th molecules/cu cm of PbPc film), than an identical SAW sensor functioning via mass loading would be. Sensitivity to a few ppm of NO2 in Ne was demonstrated.

  7. Finite Element Analysis of Bulk-Acoustic-Wave Devices: Model Setup and Applications.

    PubMed

    Thalhammer, Robert; Larson, John

    2016-04-20

    In this work, the principles of finite element modeling for the electro-acoustic simulation of bulk-acoustic- wave devices will be summarized. We will outline model setup including governing equations and boundary conditions, as well as its efficient computer implementation. Particular emphasis will be given to tailoring the model dimension to the specific requirements of the desired investigation. As 3D simulations still require a major effort, it will be illustrated that various aspects of device physics and design can be addressed already by fast and efficient 2D simulations. Multiple theoretical and experimental evidence will be presented to demonstrate the validity of the modeling concepts. Based on various examples it will be sketched how to benefit from numerical simulations for understanding fundamental effects, designing devices for actual products, and exploring novel technologies.

  8. Jump chaotic behaviour of ultra low loss bulk acoustic wave cavities

    NASA Astrophysics Data System (ADS)

    Goryachev, Maxim; Farr, Warrick G.; Galliou, Serge; Tobar, Michael E.

    2014-08-01

    We demonstrate a previously unobserved nonlinear phenomenon in an ultra-low loss quartz bulk acoustic wave cavity ( Q > 3 > 10 9), which only occurs below 20 mK in temperature and under relatively weak pumping. The phenomenon reveals the emergence of several stable equilibria (at least two foci and two nodes) and jumps between these quasi states at random times. The degree of this randomness as well as separations between levels can be controlled by the frequency of the incident carrier signal. It is demonstrated that the nature of the effect lies beyond the standard Duffing model.

  9. Jump chaotic behaviour of ultra low loss bulk acoustic wave cavities

    SciTech Connect

    Goryachev, Maxim Farr, Warrick G.; Tobar, Michael E.; Galliou, Serge

    2014-08-11

    We demonstrate a previously unobserved nonlinear phenomenon in an ultra-low loss quartz bulk acoustic wave cavity (Q>3>10{sup 9}), which only occurs below 20 mK in temperature and under relatively weak pumping. The phenomenon reveals the emergence of several stable equilibria (at least two foci and two nodes) and jumps between these quasi states at random times. The degree of this randomness as well as separations between levels can be controlled by the frequency of the incident carrier signal. It is demonstrated that the nature of the effect lies beyond the standard Duffing model.

  10. Solitary surface acoustic waves and bulk solitons in nanosecond and picosecond laser ultrasonics.

    PubMed

    Hess, Peter; Lomonosov, Alexey M

    2010-02-01

    Recent achievements of nonlinear acoustics concerning the realization of solitons and solitary waves in crystals and their surfaces attained by nanosecond and picosecond laser ultrasonics are discussed and compared. The corresponding pump-probe setups are described, which allow an all-optical contact-free excitation and detection of short strain pulses in the broad frequency range between 10 MHz and about 300 GHz. The formation of solitons in the propagating longitudinal strain pulses is investigated for nonlinear media with intrinsic lattice-based dispersion. The excitation of solitary surface acoustic waves is realized by a geometric film-based dispersion effect. Future developments and potential applications of nonlinear nanosecond and picosecond ultrasonics are discussed.

  11. Bulk and thin films of FeTe: A Moessbauer study

    NASA Technical Reports Server (NTRS)

    Escue, W. T.; Aggarwal, K.; Mendiratta, R. G.

    1977-01-01

    Studies of bulk and thin films of FeTe using Moessbauer spectroscopy showed that FeTe has one noncubic Fe (+2) site which is 3d2 4s 4p3 hybridized. The presence of dangling bands was indicated in spectra of FeTe thin films. The films showed a tendency of texture formation. The substrate was observed to influence the film structure and nature of bonds in films.

  12. Acoustic emissions during 3.1 MHz ultrasound bulk ablation in vitro.

    PubMed

    Mast, T Douglas; Salgaonkar, Vasant A; Karunakaran, Chandrapriya; Besse, John A; Datta, Saurabh; Holland, Christy K

    2008-09-01

    uncorrelated with subharmonic emissions. Subharmonic emissions were found to depend strongly on temperature in a nonlinear manner, with significant emissions occurring within different temperature ranges for each sonication amplitude. These results suggest potential roles for passive detection of acoustic emissions in guidance and control of bulk US ablation treatments.

  13. Visualization of Surface Acoustic Waves in Thin Liquid Films

    PubMed Central

    Rambach, R. W.; Taiber, J.; Scheck, C. M. L.; Meyer, C.; Reboud, J.; Cooper, J. M.; Franke, T.

    2016-01-01

    We demonstrate that the propagation path of a surface acoustic wave (SAW), excited with an interdigitated transducer (IDT), can be visualized using a thin liquid film dispensed onto a lithium niobate (LiNbO3) substrate. The practical advantages of this visualization method are its rapid and simple implementation, with many potential applications including in characterising acoustic pumping within microfluidic channels. It also enables low-cost characterisation of IDT designs thereby allowing the determination of anisotropy and orientation of the piezoelectric substrate without the requirement for sophisticated and expensive equipment. Here, we show that the optical visibility of the sound path critically depends on the physical properties of the liquid film and identify heptane and methanol as most contrast rich solvents for visualization of SAW. We also provide a detailed theoretical description of this effect. PMID:26917490

  14. Soft resonator of omnidirectional resonance for acoustic metamaterials with a negative bulk modulus

    NASA Astrophysics Data System (ADS)

    Jing, Xiaodong; Meng, Yang; Sun, Xiaofeng

    2015-11-01

    Monopolar resonance is of fundamental importance in the acoustic field. Here, we present the realization of a monopolar resonance that goes beyond the concept of Helmholtz resonators. The balloon-like soft resonator (SR) oscillates omnidirectionally and radiates from all parts of its spherical surface, eliminating the need for a hard wall for the cavity and baffle effects. For airborne sound, such a low-modulus resonator can be made extremely lightweight. Deep subwavelength resonance is achieved when the SR is tuned by adjusting the shell thickness, benefiting from the large density contrast between the shell material and the encapsulated gas. The SR resonates with near-perfect monopole symmetry, as demonstrated by the theoretical and experimental results, which are in excellent agreement. For a lattice of SRs, a band gap occurs and blocks near-total transmission, and the effective bulk modulus exhibits a prominent negative band, while the effective mass density remains unchanged. Our study shows that the SR is suitable for building 3D acoustic metamaterials and provides a basis for constructing left-handed materials as a new means of creating a negative bulk modulus.

  15. Soft resonator of omnidirectional resonance for acoustic metamaterials with a negative bulk modulus.

    PubMed

    Jing, Xiaodong; Meng, Yang; Sun, Xiaofeng

    2015-11-05

    Monopolar resonance is of fundamental importance in the acoustic field. Here, we present the realization of a monopolar resonance that goes beyond the concept of Helmholtz resonators. The balloon-like soft resonator (SR) oscillates omnidirectionally and radiates from all parts of its spherical surface, eliminating the need for a hard wall for the cavity and baffle effects. For airborne sound, such a low-modulus resonator can be made extremely lightweight. Deep subwavelength resonance is achieved when the SR is tuned by adjusting the shell thickness, benefiting from the large density contrast between the shell material and the encapsulated gas. The SR resonates with near-perfect monopole symmetry, as demonstrated by the theoretical and experimental results, which are in excellent agreement. For a lattice of SRs, a band gap occurs and blocks near-total transmission, and the effective bulk modulus exhibits a prominent negative band, while the effective mass density remains unchanged. Our study shows that the SR is suitable for building 3D acoustic metamaterials and provides a basis for constructing left-handed materials as a new means of creating a negative bulk modulus.

  16. Surface acoustic wave amplification by direct current-voltage supplied to graphene film

    NASA Astrophysics Data System (ADS)

    Insepov, Z.; Emelin, E.; Kononenko, O.; Roshchupkin, D. V.; Tnyshtykbayev, K. B.; Baigarin, K. A.

    2015-01-01

    Using a high-resolution X-Ray diffraction measurement method, the surface acoustic wave (SAW) propagation in a graphene film on the surface of a Ca3TaGa3Si2O14 (CTGS) piezoelectric crystal was investigated, where an external current was driven across the graphene film. Here, we show that the application of the DC field leads to a significant enhancement of the SAW magnitude and, as a result, to amplification of the diffraction satellites. Amplification of 33.2 dB/cm for the satellite +1, and of 13.8 dB/cm for the satellite +2, at 471 MHz has been observed where the external DC voltage of +10 V was applied. Amplification of SAW occurs above a DC field much smaller than that of a system using bulk semiconductor. Theoretical estimates are in reasonable agreement with our measurements and analysis of experimental data for other materials.

  17. Composition, Constitution and Phase Transformation Behavior in Thin-Film and Bulk Ti-Ni-Y

    NASA Astrophysics Data System (ADS)

    König, D.; Frowein, P.; Wieczorek, A.; Frenzel, J.; Hamann, S.; Eggeler, G.; Ludwig, A.

    2017-01-01

    Advanced engineering applications require new and improved shape memory alloys in bulk and thin-film form. While many Ti-Ni-based systems have been studied so far, the Ti-Ni-Y materials system was not studied in detail concerning its bulk and thin-film shape memory properties. For this reason, a Ti-Ni-Y thin-film materials library focussing on compositions close to Ni50Ti50 was fabricated by combinatorial magnetron sputtering. This library was characterized by high-throughput methods and the compositional range where phase transformations occur was identified. Ti-Ni-Y thin films exhibit a very narrow hysteresis width ∆T and allow to precisely adjust ∆T. Based on the promising results of Ti-Ni-Y thin films, which can be directly applied in microsystems, bulk alloys were fabricated in order to explore how thin-film and bulk properties of different Ti-Ni-Y compositions correlate. It turned out that Ti-Ni-Y bulk materials show different phase transformation properties compared to thin films, most importantly higher ∆T. The differences between thin-film and bulk material are discussed.

  18. Composition, Constitution and Phase Transformation Behavior in Thin-Film and Bulk Ti-Ni-Y

    NASA Astrophysics Data System (ADS)

    König, D.; Frowein, P.; Wieczorek, A.; Frenzel, J.; Hamann, S.; Eggeler, G.; Ludwig, A.

    2017-03-01

    Advanced engineering applications require new and improved shape memory alloys in bulk and thin-film form. While many Ti-Ni-based systems have been studied so far, the Ti-Ni-Y materials system was not studied in detail concerning its bulk and thin-film shape memory properties. For this reason, a Ti-Ni-Y thin-film materials library focussing on compositions close to Ni50Ti50 was fabricated by combinatorial magnetron sputtering. This library was characterized by high-throughput methods and the compositional range where phase transformations occur was identified. Ti-Ni-Y thin films exhibit a very narrow hysteresis width ∆ T and allow to precisely adjust ∆ T. Based on the promising results of Ti-Ni-Y thin films, which can be directly applied in microsystems, bulk alloys were fabricated in order to explore how thin-film and bulk properties of different Ti-Ni-Y compositions correlate. It turned out that Ti-Ni-Y bulk materials show different phase transformation properties compared to thin films, most importantly higher ∆ T. The differences between thin-film and bulk material are discussed.

  19. Characterization of organic film with scanning acoustic microscopy

    NASA Astrophysics Data System (ADS)

    Miyasaka, Chiaki; Du, Jikai; Tittmann, Bernhard R.

    2003-08-01

    The present article reports a technique to measure velocity of an organic film deposited on a homogeneous substrate, wherein the thickness of the film and the diameter of the measured area of the specimen are in the order of a few microns. A thinly sliced human kidney was selected as an example of an organic film. The thickness of the specimen was substantially 3 μm. For the substrate, fused quartz was used because its elastic properties are known and stable. The spherical acoustic lens was used to determine the position for measurement. The frequencies at 400 MHz and 600 MHz were used for the measurement and the visualization, respectively. The generation of the Rayleigh waves under the above conditions was simulated by numerical calculations based onthe wave propagation theory for layered media.

  20. In situ Magnetotransport Measurements in Ultrathin Bi Films: Evidence for Surface-Bulk Coherent Transport

    NASA Astrophysics Data System (ADS)

    Aitani, Masaki; Hirahara, Toru; Ichinokura, Satoru; Hanaduka, Masahiro; Shin, Dongyoon; Hasegawa, Shuji

    2014-11-01

    We performed in situ magnetotransport measurements on ultrathin Bi(111) films [4-30 bilayers (BLs), 16-120 Å thick] to elucidate the role of bulk or surface states in the transport phenomena. We found that the temperature dependence of the film conductivity shows no thickness dependence for the 6-16 BL films and is affected by the electron-electron scattering, suggesting surface-state dominant contribution. In contrast, the weak antilocalization effect observed by applying a magnetic field shows clear thickness dependence, indicating bulk transport. This apparent inconsistency is explained by a coherent bulk-surface coupling that produces a single channel transport. For the films thicker than 20 BLs, the behavior changes drastically which can likely be interpreted as a bulk dominant conduction.

  1. Absorption of surface acoustic waves by topological insulator thin films

    SciTech Connect

    Li, L. L.; Xu, W.

    2014-08-11

    We present a theoretical study on the absorption of the surface acoustic waves (SAWs) by Dirac electrons in topological insulator (TI) thin films (TITFs). We find that due to momentum and energy conservation laws, the absorption of the SAWs in TITFs can only be achieved via intra-band electronic transitions. The strong absorption can be observed up to sub-terahertz frequencies. With increasing temperature, the absorption intensity increases significantly and the cut-off frequency is blue-shifted. More interestingly, we find that the absorption of the SAWs by the TITFs can be markedly enhanced by the tunable subgap in the Dirac energy spectrum of the TI surface states. Such a subgap is absent in conventional two-dimensional electron gases (2DEGs) and in the gapless Dirac 2DEG such as graphene. This study is pertinent to the exploration of the acoustic properties of TIs and to potential application of TIs as tunable SAW devices working at hypersonic frequencies.

  2. Absorption of surface acoustic waves by topological insulator thin films

    NASA Astrophysics Data System (ADS)

    Li, L. L.; Xu, W.

    2014-08-01

    We present a theoretical study on the absorption of the surface acoustic waves (SAWs) by Dirac electrons in topological insulator (TI) thin films (TITFs). We find that due to momentum and energy conservation laws, the absorption of the SAWs in TITFs can only be achieved via intra-band electronic transitions. The strong absorption can be observed up to sub-terahertz frequencies. With increasing temperature, the absorption intensity increases significantly and the cut-off frequency is blue-shifted. More interestingly, we find that the absorption of the SAWs by the TITFs can be markedly enhanced by the tunable subgap in the Dirac energy spectrum of the TI surface states. Such a subgap is absent in conventional two-dimensional electron gases (2DEGs) and in the gapless Dirac 2DEG such as graphene. This study is pertinent to the exploration of the acoustic properties of TIs and to potential application of TIs as tunable SAW devices working at hypersonic frequencies.

  3. Titanium acoustic diaphragm coated with polycrystal diamond film

    SciTech Connect

    Zhiwei Zhang; Zhen Yan; Hesun Zhu

    1995-12-31

    The spherical titanium diaphragm, which is widely used in high frequency loudspeaker, coat with polycrystal diamond film (DF) was prepared for the first time in China by the method of DC arc plasma jet. Its acoustic performance was remarkably upgraded, as confirmed by Raman Shift Spectrum and frequency response curve. Its sensibility was improved by 3-6 dB and frequency widened by 5x10{sup 3}Hz. The frequency range extended from 2.2x10{sup 3}Hz to 25x10{sup 3}Hz. The preparation and process of DF is discussed.

  4. New Magnetic Materials and Phenomena for Radar and Microwave Signal Processing Devices - Bulk and Thin Film Ferrites and Metallic Films

    DTIC Science & Technology

    2009-02-15

    methods have been used to produce in-plane c-axis (IPCA) oriented barium ferrite (BaM) films on o-plane (1120) sapphire substrates with low microwave ...New magnetic materials and phenomena for radar and microwave signal processing devices - bulk and thin film ferrites and metallic films 6. AUTHOR(S...excitation properties in delay line structures. (173 words) 14. SUBJECT TERMS Microwave ferrites , yttrium iron garnet, hexagonal ferrites

  5. Acoustoelectric effects in reflection of leaky-wave-radiated bulk acoustic waves from piezoelectric crystal-conductive liquid interface.

    PubMed

    Rimeika, Romualdas; Čiplys, Daumantas; Jonkus, Vytautas; Shur, Michael

    2016-01-01

    The leaky surface acoustic wave (SAW) propagating along X-axis of Y-cut lithium tantalate crystal strongly radiates energy in the form of an obliquely propagating narrow bulk acoustic wave (BAW) beam. The reflection of this beam from the crystal-liquid interface has been investigated. The test liquids were solutions of potassium nitrate in distilled water and of lithium chloride in isopropyl alcohol with the conductivity varied by changing the solution concentration. The strong dependences of the reflected wave amplitude and phase on the liquid conductivity were observed and explained by the acoustoelectric interaction in the wave reflection region. The novel configuration of an acoustic sensor for liquid media featuring important advantages of separate measuring and sensing surfaces and rigid structure has been proposed. The application of leaky-SAW radiated bulk waves for identification of different brands of mineral water has been demonstrated.

  6. Ferroelectric Tungsten Bronze Bulk Crystals and Epitaxial Thin Films for Electro-Optic Device Applications

    DTIC Science & Technology

    1983-05-01

    23 FERROELECTRIC TUNGSTEN BRONZE BULK CRYSTALS AND EPITAXIAL THIN FILMS FOR ELECTRO-OPTIC DEVICE APPLICATIONS 10 CO O Semi-Annual Technical... THIN FILMS FOR ELECTRO-OPTIC DEVICE APPLICATIONS s TV^C or REPORT * pcmoo COVCHCO Semi-Annual Tec1! Rpt #1 for period 09/30/82-03/31/83...months, considerable progress has been made in several areas, including single crystal and thin film growth and characteriza- tion. The new

  7. Interface Selective Transient Grating Spectroscopy: Theory and Applications to Thermal Flow and Acoustic Propagation in Thin Films.

    NASA Astrophysics Data System (ADS)

    Marshall, Christopher David

    A general theoretical and experimental treatment of transient grating diffraction is developed for interfacial holographic gratings in thin film structures. The gratings are assumed to have nonuniform spatial amplitude throughout the sample. Both reflection and transmission diffraction geometries are examined where the probe beam is incident on either side of the film-substrate interface with the grating wave-vector parallel to the interface. For samples in which the grating amplitude perpendicular to the sample interface varies slowly relative to the optical wavelength, the majority of the reflection geometry signal amplified is shown to arise from the surface or interfacial region. In contrast, the transmission geometry signal amplitude is dominated by contributions from the bulk of the sample. Three different material systems are examined. The first is a thin (<1 mm) molecular anthracene crystal on a glass substrate in which electronic (exciton) and wave-guided acoustic gratings are generated and probed. Four different transient grating geometries are shown to yield unique time dependent responses illustrating the sensitivity of the transient grating geometry to the spatial origin of the signal. A theoretical model is developed to demonstrate the spatial selectivity of the technique. The second and third systems are thin (50-350 nm thick) films of the high temperature superconductor YBa_2Cu _3O_{rm 7-x} (YBCO) on either MgO or SrTiO _3 substrates. Anisotropic thermal diffusion constants in the YBCO films are measured over a 17 to 300 K temperature range. A detailed understanding is obtained of the time dependent heat flow in the regions adjacent to the film-substrate interface, the free film surface, and the bulk of the film. A temperature dependent thermal barrier that significantly restricts heat transfer from the film into the MgO substrate is observed and quantified. The rate of flow thru the YBCO/MgO interface is measured to be 10 to 100 times less than the

  8. Fatigue crack monitoring with coupled piezoelectric film acoustic emission sensors

    NASA Astrophysics Data System (ADS)

    Zhou, Changjiang

    Fatigue-induced cracking is a commonly seen problem in civil infrastructures reaching their original design life. A number of high-profile accidents have been reported in the past that involved fatigue damage in structures. Such incidences often happen without prior warnings due to lack of proper crack monitoring technique. In order to detect and monitor the fatigue crack, acoustic emission (AE) technique, has been receiving growing interests recently. AE can provide continuous and real-time monitoring data on damage progression in structures. Piezoelectric film AE sensor measures stress-wave induced strain in ultrasonic frequency range and its feasibility for AE signal monitoring has been demonstrated recently. However, extensive work in AE monitoring system development based on piezoelectric film AE sensor and sensor characterization on full-scale structures with fatigue cracks, have not been done. A lack of theoretical formulations for understanding the AE signals also hinders the use of piezoelectric film AE sensors. Additionally, crack detection and source localization with AE signals is a very important area yet to be explored for this new type of AE sensor. This dissertation presents the results of both analytical and experimental study on the signal characteristics of surface stress-wave induced AE strain signals measured by piezoelectric film AE sensors in near-field and an AE source localization method based on sensor couple theory. Based on moment tensor theory, generalized expression for AE strain signal is formulated. A special case involving the response of piezoelectric film AE sensor to surface load is also studied, which could potentially be used for sensor calibration of this type of sensor. A new concept of sensor couple theory based AE source localization technique is proposed and validated with both simulated and experimental data from fatigue test and field monitoring. Two series of fatigue tests were conducted to perform fatigue crack

  9. Temperature-dependent differences in the nonlinear acoustic behavior of ultrasound contrast agents revealed by high-speed imaging and bulk acoustics.

    PubMed

    Mulvana, Helen; Stride, Eleanor; Tang, Mengxing; Hajnal, Jo V; Eckersley, Robert

    2011-09-01

    Previous work by the authors has established that increasing the temperature of the suspending liquid from 20°C to body temperature has a significant impact on the bulk acoustic properties and stability of an ultrasound contrast agent suspension (SonoVue, Bracco Suisse SA, Manno, Lugano, Switzerland). In this paper the influence of temperature on the nonlinear behavior of microbubbles is investigated, because this is one of the most important parameters in the context of diagnostic imaging. High-speed imaging showed that raising the temperature significantly influences the dynamic behavior of individual microbubbles. At body temperature, microbubbles exhibit greater radial excursion and oscillate less spherically, with a greater incidence of jetting and gas expulsion, and therefore collapse, than they do at room temperature. Bulk acoustics revealed an associated increase in the harmonic content of the scattered signals. These findings emphasize the importance of conducting laboratory studies at body temperature if the results are to be interpreted for in vivo applications.

  10. Detection of shorter-than-skin-depth acoustic pulses in a metal film via transient reflectivity

    NASA Astrophysics Data System (ADS)

    Manke, K. J.; Maznev, A. A.; Klieber, C.; Temnov, V. V.; Makarov, D.; Baek, S.-H.; Eom, C.-B.; Nelson, Keith A.

    2012-12-01

    Short acoustic pulses are generated in SrRuO3 transducers and detected at the surface of gold films by transient reflectivity. Contrary to expectations, acoustic pulses that are shorter than the optical skin depth of gold are resolved. A comparison of gold detection films that were grown under different deposition conditions demonstrates that the microstructure of a detection film can impact the shape of the detected signal.

  11. Thermoelectric and bulk mobility measurements in pentacene thin films

    SciTech Connect

    Kim, Gunho; Shtein, Max; Pipe, Kevin P.

    2011-03-02

    Low-noise thermoelectric and electrical measurements were used to derive the dependences of Seebeck coefficient and hole mobility on carrier concentration and grain size in the “bulk” regions of thermally evaporated pentacene thin films (in contrast to the channel field-effect mobility typically measured using thin-film transistor geometries). Distinct charge transport regimes were observed for larger (0.5 and 0.8 μm ) and smaller (0.2 μm) grain sizes, attributed to carrier-dopant scattering and percolation, respectively.

  12. Fabrication and Operation of Acoustofluidic Devices Supporting Bulk Acoustic Standing Waves for Sheathless Focusing of Particles.

    PubMed

    Shields, C Wyatt; Cruz, Daniela F; Ohiri, Korine A; Yellen, Benjamin B; Lopez, Gabriel P

    2016-03-06

    Acoustophoresis refers to the displacement of suspended objects in response to directional forces from sound energy. Given that the suspended objects must be smaller than the incident wavelength of sound and the width of the fluidic channels are typically tens to hundreds of micrometers across, acoustofluidic devices typically use ultrasonic waves generated from a piezoelectric transducer pulsating at high frequencies (in the megahertz range). At characteristic frequencies that depend on the geometry of the device, it is possible to induce the formation of standing waves that can focus particles along desired fluidic streamlines within a bulk flow. Here, we describe a method for the fabrication of acoustophoretic devices from common materials and clean room equipment. We show representative results for the focusing of particles with positive or negative acoustic contrast factors, which move towards the pressure nodes or antinodes of the standing waves, respectively. These devices offer enormous practical utility for precisely positioning large numbers of microscopic entities (e.g., cells) in stationary or flowing fluids for applications ranging from cytometry to assembly.

  13. Fabrication and Operation of Acoustofluidic Devices Supporting Bulk Acoustic Standing Waves for Sheathless Focusing of Particles

    PubMed Central

    Shields, C. Wyatt; Cruz, Daniela F.; Ohiri, Korine A.; Yellen, Benjamin B.; Lopez, Gabriel P.

    2016-01-01

    Acoustophoresis refers to the displacement of suspended objects in response to directional forces from sound energy. Given that the suspended objects must be smaller than the incident wavelength of sound and the width of the fluidic channels are typically tens to hundreds of micrometers across, acoustofluidic devices typically use ultrasonic waves generated from a piezoelectric transducer pulsating at high frequencies (in the megahertz range). At characteristic frequencies that depend on the geometry of the device, it is possible to induce the formation of standing waves that can focus particles along desired fluidic streamlines within a bulk flow. Here, we describe a method for the fabrication of acoustophoretic devices from common materials and clean room equipment. We show representative results for the focusing of particles with positive or negative acoustic contrast factors, which move towards the pressure nodes or antinodes of the standing waves, respectively. These devices offer enormous practical utility for precisely positioning large numbers of microscopic entities (e.g., cells) in stationary or flowing fluids for applications ranging from cytometry to assembly. PMID:27022681

  14. Surface Acoustic Wave (SAW) Resonators for Monitoring Conditioning Film Formation.

    PubMed

    Hohmann, Siegfried; Kögel, Svea; Brunner, Yvonne; Schmieg, Barbara; Ewald, Christina; Kirschhöfer, Frank; Brenner-Weiß, Gerald; Länge, Kerstin

    2015-05-21

    We propose surface acoustic wave (SAW) resonators as a complementary tool for conditioning film monitoring. Conditioning films are formed by adsorption of inorganic and organic substances on a substrate the moment this substrate comes into contact with a liquid phase. In the case of implant insertion, for instance, initial protein adsorption is required to start wound healing, but it will also trigger immune reactions leading to inflammatory responses. The control of the initial protein adsorption would allow to promote the healing process and to suppress adverse immune reactions. Methods to investigate these adsorption processes are available, but it remains difficult to translate measurement results into actual protein binding events. Biosensor transducers allow user-friendly investigation of protein adsorption on different surfaces. The combination of several transduction principles leads to complementary results, allowing a more comprehensive characterization of the adsorbing layer. We introduce SAW resonators as a novel complementary tool for time-resolved conditioning film monitoring. SAW resonators were coated with polymers. The adsorption of the plasma proteins human serum albumin (HSA) and fibrinogen onto the polymer-coated surfaces were monitored. Frequency results were compared with quartz crystal microbalance (QCM) sensor measurements, which confirmed the suitability of the SAW resonators for this application.

  15. Surface Acoustic Wave (SAW) Resonators for Monitoring Conditioning Film Formation

    PubMed Central

    Hohmann, Siegfried; Kögel, Svea; Brunner, Yvonne; Schmieg, Barbara; Ewald, Christina; Kirschhöfer, Frank; Brenner-Weiß, Gerald; Länge, Kerstin

    2015-01-01

    We propose surface acoustic wave (SAW) resonators as a complementary tool for conditioning film monitoring. Conditioning films are formed by adsorption of inorganic and organic substances on a substrate the moment this substrate comes into contact with a liquid phase. In the case of implant insertion, for instance, initial protein adsorption is required to start wound healing, but it will also trigger immune reactions leading to inflammatory responses. The control of the initial protein adsorption would allow to promote the healing process and to suppress adverse immune reactions. Methods to investigate these adsorption processes are available, but it remains difficult to translate measurement results into actual protein binding events. Biosensor transducers allow user-friendly investigation of protein adsorption on different surfaces. The combination of several transduction principles leads to complementary results, allowing a more comprehensive characterization of the adsorbing layer. We introduce SAW resonators as a novel complementary tool for time-resolved conditioning film monitoring. SAW resonators were coated with polymers. The adsorption of the plasma proteins human serum albumin (HSA) and fibrinogen onto the polymer-coated surfaces were monitored. Frequency results were compared with quartz crystal microbalance (QCM) sensor measurements, which confirmed the suitability of the SAW resonators for this application. PMID:26007735

  16. Thick Films acoustic sensors devoted to MTR environment measurements. Thick Films acoustic sensors devoted to Material Testing Reactor environment measurements

    SciTech Connect

    Very, F.; Rosenkrantz, E.; Combette, P.; Ferrandis, J.Y.; Fourmentel, D.; Destouches, C.; Villard, J.F.

    2015-07-01

    The development of advanced instrumentation for in-pile experiments in Material Testing Reactor constitutes a main goal for the improvement of the nuclear fuel behavior knowledge. An acoustic method for fission gas release detection was tested with success during a first experiment called REMORA 3 in 2010 and 2011, and the results were used to differentiate helium and fission gas release kinetics under transient operating conditions. This experiment was lead at OSIRIS reactor (CEA Saclay, France). The maximal temperature on the sensor during the irradiation was about 150 deg. C. In this paper we present a thick film transducer produce by screen printing process. The screen printing of piezoelectric offers a wide range of possible applications for the development of acoustic sensors and piezoelectric structure for measurements in high temperature environment. We firstly produced a Lead Zirconate Titanate (PZT) based paste composed of Pz27 powder from Ferroperm, CF7575 glass, and organic solvent ESL 400. Likewise a Bismuth Titanate based paste synthesized in our laboratory was produced. With these inks we produced thick film up to 130 μm by screen printing process. Material properties characterizations of these thick-film resonators are essential for device design and applications. The piezoelectric coefficients d33 and pyro-electric P(T) coefficient are investigated. The highest P(T) and d33 are respectively 80 μC.m{sup -2}.K{sup -1} and 130 μC.N{sup -1} for the PZT transducer -which validates the fabrication process-. In view of the development of this transducer oriented for high temperature and irradiation environment, we investigated the electrical properties of the transducers for different ranges of frequencies and temperature - from 20 Hz up to 40 MHz between 30 and 400 deg. C. We highlight the evolution of the impedance response and piezoelectric parameters of screen printed piezoelectric structures on alumina. Shortly an irradiation will be realized in

  17. Response of acoustic and elastic properties to pressure and crystallization of Ce-based bulk metallic glass

    NASA Astrophysics Data System (ADS)

    Zhang, B.; Wang, R. J.; Wang, W. H.

    2005-09-01

    The density and acoustic velocities of a Ce70Al10Ni10Cu10 bulk metallic glass (BMG) under hydrostatic-pressure (up to 0.5GPa ) and in crystallized state in ambient conditions were measured in situ by a pulse echo overlap method. The pressure derivatives of velocities and Grüneisen parameters as well as the equation of state (EOS) of the BMG were determined and compared to those of various other BMGs and nonmetallic glasses. Surprisingly, the BMG, unlike other BMGs with normal mode stiffness, exhibits an anomalous soft longitudinal acoustic mode under pressure similar to that of typical oxide glasses. An unusually large softening of longitudinal acoustic phonons in the BMG, relative to its crystalline state, is also observed, analogous with that in oxide glasses. The possible origin for the anomaly is the intrinsic glassy structure containing short-range covalent bonds.

  18. Spin Orbit Torque in TbCo Films with Bulk Perpendicular Magnetic Anisotropy

    NASA Astrophysics Data System (ADS)

    Ueda, Kohei; Mann, Maxwell; Tan, Aik-Jun; Beach, Geoffrey. S. D.

    Spin-orbit torque (SOT) has generated considerable interest for manipulating magnetization in spintronic devices with ultra-low dissipation. Recent research has demonstrated that highly efficient magnetization control can be driven by current-induced SOT in ferromagnet/heavy metals bilayers with strong spin orbit coupling. However, most work on SOT has focused on ultra-thin magnetic films with interfacial perpendicular magnetic anisotropy (PMA), whereas future devices will require bulk PMA for sufficient thermal stability. Recently, Zhao et al reported SOT induced magnetization switching in a bulk PMA material; however, the films examined were still rather thin. Here we examine spin orbit torques in TbCo alloy films with bulk PMA, sandwiched between top and bottom Ta layers. By performing conventional harmonic and current-induced switching measurements, we quantified the current-induced effective fields generated by damping-like (DL) and field-like (FL) torques. The DL torque is much larger than FL torque, and corresponds to an effective spin Hall angle consistent with that of Ta. Owing to the relatively small saturation magnetized of these ferrimagnetic materials, the current-induced effective field is comparable to that observed in nm-thick Co films, despite the much larger film thicknesses used here. These results demonstrate ferromagnetic alloys with bulk PMA can be engineered to simultaneously provide thermal stability and efficient SOT switching.

  19. Bulk flow coupled to a viscous interfacial film sheared by a rotating knife edge

    NASA Astrophysics Data System (ADS)

    Raghunandan, Aditya; Rasheed, Fayaz; Hirsa, Amir; Lopez, Juan

    2015-11-01

    The measurement of the interfacial properties of highly viscous biofilms, such as DPPC (the primary component of lung surfactant), present on the surface of liquids (bulk phase) continues to attract significant attention. Most measurement techniques rely on shearing the interfacial film and quantifying its viscous response in terms of a surface (excess) viscosity at the air-liquid interface. The knife edge viscometer offers a significant advantage over other approaches used to study highly viscous films as the film is directly sheared by a rotating knife edge in direct contact with the film. However, accurately quantifying the viscous response is non-trivial and involves accounting for the coupled interfacial and bulk phase flows. Here, we examine the nature of the viscous response of water insoluble DPPC films sheared in a knife edge viscometer over a range of surface packing, and its influence on the strength of the coupled bulk flow. Experimental results, obtained via Particle Image Velocimetry in the bulk and at the surface (via Brewster Angle Microscopy), are compared with numerical flow predictions to quantify the coupling across hydrodynamic flow regimes, from the Stokes flow limit to regimes where flow inertia is significant. Supported by NNX13AQ22G, National Aeronautics and Space Administration.

  20. Materials Analysis of CED Nb Films Being Coated on Bulk Nb Single Cell SRF Cavities

    SciTech Connect

    Zhao, Xin; Reece, Charles; Palczewski, Ari; Ciovati, Gianluigi; Krishnan, Mahadevan; James, Colt; Irfan, Irfan

    2013-09-01

    This study is an on-going research on depositing a Nb film on the internal wall of bulk Nb single cell SRF cavities, via a cathodic arc Nb plasma ions source, an coaxial energetic condensation (CED) facility at AASC company. The motivation is to firstly create a homoepitaxy-like Nb/Nb film in a scale of a ~1.5GHz RF single cell cavity. Next, through SRF measurement and materials analysis, it might reveal the baseline properties of the CED-type homoepitaxy Nb films. Literally, a top-surface layer of Nb films which sustains SRF function, always grows up in homo-epitaxy mode, on top of a Nb nucleation layer. Homo-epitaxy growth of Nb must be the final stage (a crystal thickening process) of any coatings of Nb film on alternative cavity structure materials. Such knowledge of Nb-Nb homo-epitaxy is useful to create future realistic SRF cavity film coatings, such as hetero-epitaxy Nb/Cu Films, or template-layer-mitigated Nb films. One large-grain, and three fine grain bulk Nb cavities were coated. They went through cryogenic RF measurement. Preliminary results show that the Q0 of a Nb film could be as same as the pre-coated bulk Nb surface (which received a chemically-buffered polishing plus a light electro-polishing); but quality factor of two tested cavities dropped quickly. We are investigating if the severe Q-slope is caused by hydrogen incorporation before deposition, or is determined by some structural defects during Nb film growth.

  1. Microstructure and Magnetic Properties of PrMnO{sub 3} Bulk and Thin Film

    SciTech Connect

    Lim, K. P.; Halim, S. A.; Chen, S. K.; Ng, S. W.; Wong, J. K.; Gan, H. M. Albert; Woon, H. S.

    2011-03-30

    Perovskite PrMnO{sub 3}(PMO) had been prepared in bulk by solid state reaction and thin films on corning glass, fused silica and MgO (100) glass substrate by pulsed laser deposition technique. SEM micrographs show that grains with size 2{approx}3 {mu}m is observed in bulk PMO while thin films PMO show strongly connected grain structure with particle size that not larger than 100 nm. X-ray diffraction analysis shows that all samples are in single phase with orthorhombic crystal structure. Bulk PMO sample had lattice strain of 0.134% which is the lowest value among others. However, larger lattice strain was observed in thin film samples due to lattice mismatch between film-substrate and caused the MnO{sub 6} to deform. All samples shown paramagnetic or antiferromagnetic behavior, enhancement in magnetization value occurred for all PMO grew as film. We believe that larger lattice strain favor the grain growth of PMO towards more order phase. In summary, formation of structure and microstructure of thin film PMO depends on type of substrate used and it affect the magnetic property.

  2. Layered surface acoustic wave devices for film characterization and sensor applications

    NASA Astrophysics Data System (ADS)

    Pedrick, Michael K.

    2007-05-01

    This work has introduced novel applications for Layered Surface Acoustic Wave (SAW) devices along with concepts for enhanced sensitivity via refined modeling techniques. The derivation of Love Wave and Rayleigh wave propagation pertinent to SAW substrates with thin film overlayers was explored. Novel aspects were presented for Finite Element analysis of Layered SAW sensors. This included coordinate transformations of model geometries to coincide with crystallographic orientations known to generate Surface Skimming Bulk Waves (SSBW) and various Rayleigh wave types of propagation in ST Quartz, 90° rotated ST Quartz, and 77° Y rotated Lithium Tantalate. This work has shown for the first time, FEM prediction of SSBW, Generalized SAW and High Velocity SAW waves. Rayleigh damping properties were extended to develop a Finite element model capable of predicting Layered SAW response to glass transition in a polymer film. The ability to monitor localized mechanical behavior in a PMMA film was explored with Love Waves generated by 90° rotated ST Quartz and Shear Vertical (SV)-SAWs generated by 77° Y rotated Lithium Tantalate. Similar trends were found experimentally as compared to the Finite element models. The capability of Love Wave devices for monitoring polymer film curing behavior was investigated. The ability to qualitatively assess the bond quality between film and substrate was also demonstrated based on the characteristics of the transmitted frequency response. The results of these developments have laid the ground work for developing diagnostic tools to better characterize film behavior in practical applications. Several sensor applications for Layered SAW devices were discussed. The Shear Horizontal displacement of the Love Wave device was exploited to demonstrate the capability of such a sensor for ice detection. A clear distinction between air, water, and ice loading was found with Love Waves whereas SV-SAWs were unable to distinguish between liquid and ice

  3. Acoustic streaming in two-dimensional freely suspended smectic liquid crystal films

    NASA Astrophysics Data System (ADS)

    Yablonskii, S. V.; Kurbatov, N. M.; Parfenyev, V. M.

    2017-01-01

    We study horizontal streaming excited by means of a low-frequency and low-intensity acoustic wave in 2D freely suspended films of thermotropic smectic liquid crystals. Acoustic pressure induces fast periodic transverse oscillations of the film, which produce in-plane stationary couples of vortices slowly rotating in opposite directions owing to hydrodynamic nonlinearity. The parameters of the vortices are measured using a new method, based on tracking solidlike disk-shaped islands. The horizontal motion occurs only when the amplitude of the acoustic pressure exceeds the threshold value, which can be explained by Bingham-like behavior of the smectic film. The measurements above threshold are in good agreement with existing theoretical predictions. We demonstrate experimentally that in-plane flow is well controlled by changing the acoustic pressure, excitation frequency, and geometry of the film. The observations open the way to using the phenomenon in nondisplay applications.

  4. Thick-film acoustic emission sensors for use in structurally integrated condition-monitoring applications.

    PubMed

    Pickwell, Andrew J; Dorey, Robert A; Mba, David

    2011-09-01

    Monitoring the condition of complex engineering structures is an important aspect of modern engineering, eliminating unnecessary work and enabling planned maintenance, preventing failure. Acoustic emissions (AE) testing is one method of implementing continuous nondestructive structural health monitoring. A novel thick-film (17.6 μm) AE sensor is presented. Lead zirconate titanate thick films were fabricated using a powder/sol composite ink deposition technique and mechanically patterned to form a discrete thick-film piezoelectric AE sensor. The thick-film sensor was benchmarked against a commercial AE device and was found to exhibit comparable responses to simulated acoustic emissions.

  5. Optical properties of Bi2Se3: from bulk to ultrathin films

    NASA Astrophysics Data System (ADS)

    Eddrief, M.; Vidal, F.; Gallas, B.

    2016-12-01

    We report on the determination of the dielectric functions of Bi2Se3 thin films and bulk material. The Bi2Se3 thin films with thicknesses ranging from 3-54 quintuple layers (QL) were grown by molecular beam epitaxy on GaAs(1 1 1)B substrates and the optical properties were determined from spectroscopic ellipsometry in the range of 0.5 eV-6 eV. We observed five absorption bands in the bulk sample, with a strong maximum near 2 eV, which were also present in the films down to 19 QL. Reducing the number below 19 QL in the Bi2Se3 films caused dampening and broadening of the bulk absorption bands below 2 eV, and a shift to a higher energy of the band near 2 eV. Our experimental results thus provide evidence of marked changes in the joint density of states of Bi2Se3 below 19 QL, indicating that the whole bulk band structure is affected for the ultrathin epilayers.

  6. Surface acoustic wave amplification by direct current-voltage supplied to graphene film

    SciTech Connect

    Insepov, Z.; Emelin, E.; Kononenko, O.; Roshchupkin, D. V.; Tnyshtykbayev, K. B.; Baigarin, K. A.

    2015-01-12

    Using a high-resolution X-Ray diffraction measurement method, the surface acoustic wave (SAW) propagation in a graphene film on the surface of a Ca{sub 3}TaGa{sub 3}Si{sub 2}O{sub 14} (CTGS) piezoelectric crystal was investigated, where an external current was driven across the graphene film. Here, we show that the application of the DC field leads to a significant enhancement of the SAW magnitude and, as a result, to amplification of the diffraction satellites. Amplification of 33.2 dB/cm for the satellite +1, and of 13.8 dB/cm for the satellite +2, at 471 MHz has been observed where the external DC voltage of +10 V was applied. Amplification of SAW occurs above a DC field much smaller than that of a system using bulk semiconductor. Theoretical estimates are in reasonable agreement with our measurements and analysis of experimental data for other materials.

  7. Near infrared to ultraviolet optical properties of bulk single crystal and nanocrystal thin film iron pyrite.

    PubMed

    Subedi, Indra; Bhandari, Khagendra P; Ellingson, Randall J; Podraza, Nikolas J

    2016-07-22

    We report optical properties of iron pyrite (FeS2) determined from ex situ spectroscopic ellipsometry measurements made on both a commercially available bulk single crystal and nanocrystalline thin film over a spectral range of 0.735-5.887 eV. The complex dielectric function, ε (E) = ε 1 (E) + iε 2 (E), spectra have been determined by fitting a layered parametric model to the ellipsometric measurements. Spectra in ε are modeled using a Kramers-Kronig consistent critical point parabolic band model involving seven critical points for the bulk single crystal and four critical points for the nanocrystalline film. Absorption coefficient spectra for both types of samples are also determined from ε. Critical point features in the nanocrystalline films are broader, have lower amplitude and lower energy critical points detected having a small blue shift when compared to the single crystal sample.

  8. Mechanical Characterization of Nanoporous Thin Films by Nanoindentation and Laser-induced Surface Acoustic Waves

    NASA Astrophysics Data System (ADS)

    Chow, Gabriel

    Thin films represent a critical sector of modern engineering that strives to produce functional coatings at the smallest possible length scales. They appear most commonly in semiconductors where they form the foundation of all electronic circuits, but exist in many other areas to provide mechanical, electrical, chemical, and optical properties. The mechanical characterization of thin films has been a continued challenge due foremost to the length scales involved. However, emerging thin films focusing on materials with significant porosity, complex morphologies, and nanostructured surfaces produce additional difficulties towards mechanical analysis. Nanoindentation has been the dominant thin film mechanical characterization technique for the last decade because of the quick results, wide range of sample applicability, and ease of sample preparation. However, the traditional nanoindentation technique encounters difficulties for thin porous films. For such materials, alternative means of analysis are desirable and the lesser known laser-induced surface acoustic wave technique (LiSAW) shows great potential in this area. This dissertation focuses on studying thin, porous, and nanostructured films by nanoindentation and LiSAW techniques in an effort to directly correlate the two methodologies and to test the limits and applicabilities of each technique on challenging media. The LiSAW technique is particularly useful for thin porous films because unlike indentation, the substrate is properly accounted for in the wave motion analysis and no plastic deformation is necessary. Additionally, the use of lasers for surface acoustic wave generation and detection allows the technique to be fully non-contact. This is desirable in the measurement of thin, delicate, and porous films where physical sample probing may not be feasible. The LiSAW technique is also valuable in overcoming nanoscale roughness, particularly for films that cannot be mechanically polished, since typical SAW

  9. Bulk organisation and alignment in Langmuir and Langmuir-Blodgett films of tetrachloroperylene tetracarboxylic acid esters

    NASA Astrophysics Data System (ADS)

    Modlińska, Anna; Filipowicz, Marek; Martyński, Tomasz

    2016-12-01

    Perylene derivatives with chlorine atoms attached at the bay position to the dye core are expected to affect organisation and tendency to aggregation in Langmuir and Langmuir-Blodgett (LB) films. Therefore, newly synthesized core-twisted homologous series of tetrachloroperylene tetracarboxylic acid esters with n = 1,4,5,6,9 carbon atoms in terminal alkyl chains were studied. Phase transitions and crystalline structures were specified by differential scanning calorimetry (DSC) and single crystal X-ray diffraction (XRD), respectively. Intermolecular interactions and organisation of the dyes in monomolecular films were investigated by means of Brewster angle microscope (BAM), UV-Vis absorption and emission spectroscopy, fluorescence microscopy and atomic force microscopy (AFM). The dyes investigated do not form thermotropic mesogenic phases in bulk. The crystalline triclinic elementary cell with P-1 symmetry is revealed from X-ray experiments. In Langmuir and Langmuir-Blodgett films molecular tilted head-on alignment is postulated. Spectroscopic research confirmed by AFM texture images of the LB films show that in the Langmuir and LB films the dyes, depending on length of terminal chains, have a tendency to create H or I molecular aggregates. The impact of the twisted core on the molecular behavior in a bulk and thin films is discussed.

  10. Observation of the fundamental Nyquist noise limit in an ultra-high Q-factor cryogenic bulk acoustic wave cavity

    SciTech Connect

    Goryachev, Maxim Ivanov, Eugene N.; Tobar, Michael E.; Kann, Frank van; Galliou, Serge

    2014-10-13

    Thermal Nyquist noise fluctuations of high-Q bulk acoustic wave cavities have been observed at cryogenic temperatures with a DC superconducting quantum interference device amplifier. High Q modes with bandwidths of few tens of milliHz produce thermal fluctuations with a signal-to-noise ratio of up to 23 dB. The estimated effective temperature from the Nyquist noise is in good agreement with the physical temperature of the device, confirming the validity of the equivalent circuit model and the non-existence of any excess resonator self-noise. The measurements also confirm that the quality factor remains extremely high (Q > 10{sup 8} at low order overtones) for very weak (thermal) system motion at low temperatures, when compared to values measured with relatively strong external excitation. This result represents an enabling step towards operating such a high-Q acoustic device at the standard quantum limit.

  11. Surface and bulk crystallization of amorphous solid water films: Confirmation of “top-down” crystallization

    SciTech Connect

    Yuan, Chunqing; Smith, R. Scott; Kay, Bruce D.

    2016-01-11

    Here, the crystallization kinetics of nanoscale amorphous solid water (ASW) films are investigated using temperature-programmed desorption (TPD) and reflection absorption infrared spectroscopy (RAIRS). TPD measurements are used to probe surface crystallization and RAIRS measurements are used to probe bulk crystallization. Isothermal TPD results show that surface crystallization is independent of the film thickness (from 100 to 1000 ML). Conversely, the RAIRS measurements show that the bulk crystallization time increases linearly with increasing film thickness. These results suggest that nucleation and crystallization begin at the ASW/vacuum interface and then the crystallization growth front propagates linearly into the bulk. This mechanism was confirmed by selective placement of an isotopic layer (5% D2O in H2O) at various positions in an ASW (H2O) film. In this case, the closer the isotopic layer was to the vacuum interface, the earlier the isotopic layer crystallized. These experiments provide direct evidence to confirm that ASW crystallization in vacuum proceeds by a “top-down” crystallization mechanism.

  12. Surface and bulk crystallization of amorphous solid water films: Confirmation of “top-down” crystallization

    DOE PAGES

    Yuan, Chunqing; Smith, R. Scott; Kay, Bruce D.

    2016-01-11

    Here, the crystallization kinetics of nanoscale amorphous solid water (ASW) films are investigated using temperature-programmed desorption (TPD) and reflection absorption infrared spectroscopy (RAIRS). TPD measurements are used to probe surface crystallization and RAIRS measurements are used to probe bulk crystallization. Isothermal TPD results show that surface crystallization is independent of the film thickness (from 100 to 1000 ML). Conversely, the RAIRS measurements show that the bulk crystallization time increases linearly with increasing film thickness. These results suggest that nucleation and crystallization begin at the ASW/vacuum interface and then the crystallization growth front propagates linearly into the bulk. This mechanism wasmore » confirmed by selective placement of an isotopic layer (5% D2O in H2O) at various positions in an ASW (H2O) film. In this case, the closer the isotopic layer was to the vacuum interface, the earlier the isotopic layer crystallized. These experiments provide direct evidence to confirm that ASW crystallization in vacuum proceeds by a “top-down” crystallization mechanism.« less

  13. Surface and bulk crystallization of amorphous solid water films: Confirmation of “top-down” crystallization

    SciTech Connect

    Yuan, Chunqing; Smith, R. Scott; Kay, Bruce D.

    2016-10-01

    The crystallization kinetics of nanoscale amorphous solid water (ASW) films are investigated using temperature-programmed desorption (TPD) and reflection absorption infrared spectroscopy (RAIRS). TPD measurements are used to probe surface crystallization and RAIRS measurements are used to probe bulk crystallization. Isothermal TPD results show that surface crystallization is independent of the film thickness (from 100 to 1000 ML). Conversely, the RAIRS measurements show that the bulk crystallization time increases linearly with increasing film thickness. These results suggest that nucleation and crystallization begin at the ASW/vacuum interface and then the crystallization growth front propagates linearly into the bulk. This mechanism was confirmed by selective placement of an isotopic layer (5% D2O in H2O) at various positions in an ASW (H2O) film. In this case, the closer the isotopic layer was to the vacuum interface, the earlier the isotopic layer crystallized. These experiments provide direct evidence to confirm that ASW crystallization in vacuum proceeds by a “top-down” crystallization mechanism.

  14. Surface Acoustic Wave Monitor for Deposition and Analysis of Ultra-Thin Films

    NASA Technical Reports Server (NTRS)

    Hines, Jacqueline H. (Inventor)

    2015-01-01

    A surface acoustic wave (SAW) based thin film deposition monitor device and system for monitoring the deposition of ultra-thin films and nanomaterials and the analysis thereof is characterized by acoustic wave device embodiments that include differential delay line device designs, and which can optionally have integral reference devices fabricated on the same substrate as the sensing device, or on a separate device in thermal contact with the film monitoring/analysis device, in order to provide inherently temperature compensated measurements. These deposition monitor and analysis devices can include inherent temperature compensation, higher sensitivity to surface interactions than quartz crystal microbalance (QCM) devices, and the ability to operate at extreme temperatures.

  15. Communication: Distinguishing between bulk and interface-enhanced crystallization in nanoscale films of amorphous solid water

    NASA Astrophysics Data System (ADS)

    Yuan, Chunqing; Smith, R. Scott; Kay, Bruce D.

    2017-01-01

    The crystallization of amorphous solid water (ASW) nanoscale films was investigated using reflection absorption infrared spectroscopy. Two ASW film configurations were studied. In one case the ASW film was deposited on top of and capped with a decane layer ("sandwich" configuration). In the other case, the ASW film was deposited on top of a decane layer and not capped ("no cap" configuration). Crystallization of ASW films in the "sandwich" configuration is about eight times slower than in the "no cap." Selective placement of an isotopic layer (5% D2O in H2O) at various positions in an ASW (H2O) film was used to determine the crystallization mechanism. In the "sandwich" configuration, the crystallization kinetics were independent of the isotopic layer placement whereas in the "no cap" configuration the closer the isotopic layer was to the vacuum interface, the earlier the isotopic layer crystallized. These results are consistent with a mechanism whereby the decane overlayer suppresses surface nucleation and provide evidence that the observed ASW crystallization in "sandwich" films is the result of uniform bulk nucleation.

  16. Method and apparatus for detecting internal structures of bulk objects using acoustic imaging

    DOEpatents

    Deason, Vance A.; Telschow, Kenneth L.

    2002-01-01

    Apparatus for producing an acoustic image of an object according to the present invention may comprise an excitation source for vibrating the object to produce at least one acoustic wave therein. The acoustic wave results in the formation of at least one surface displacement on the surface of the object. A light source produces an optical object wavefront and an optical reference wavefront and directs the optical object wavefront toward the surface of the object to produce a modulated optical object wavefront. A modulator operatively associated with the optical reference wavefront modulates the optical reference wavefront in synchronization with the acoustic wave to produce a modulated optical reference wavefront. A sensing medium positioned to receive the modulated optical object wavefront and the modulated optical reference wavefront combines the modulated optical object and reference wavefronts to produce an image related to the surface displacement on the surface of the object. A detector detects the image related to the surface displacement produced by the sensing medium. A processing system operatively associated with the detector constructs an acoustic image of interior features of the object based on the phase and amplitude of the surface displacement on the surface of the object.

  17. Interaction of surface and bulk acoustic waves with a two-dimensional semimetal

    SciTech Connect

    Kovalev, V. M. Chaplik, A. V.

    2015-02-15

    The interaction of a surface elastic Rayleigh wave with an electron-hole plasma in a two-dimensional semimetal has been theoretically studied as determined by the deformation potential and piezoelectric mechanisms. Dispersion equations describing the coupled plasmon-acoustic modes for both types of interaction are derived, and damping of the Rayleigh wave is calculated. The damping of the acoustic and optical plasmon modes, which is related to the sound emission by plasma oscillations into the substrate volume, is calculated and it is shown that this sound emission is predominantly determined by the acoustic plasmon mode in the case of a deformation potential mechanism and by the optical mode in the case of a piezoelectric mechanism.

  18. Sputtered nickel oxide thin film for efficient hole transport layer in polymer–fullerene bulk-heterojunction organic solar cell

    SciTech Connect

    Widjonarko, N. Edwin; Ratcliff, Erin L.; Perkins, Craig L.; Sigdel, Ajaya K.; Zakutayev, Andriy; Ndione, Paul F.; Gillaspie, Dane T.; Ginley, David S.; Olson, Dana C.; Berry, Joseph J.

    2012-03-01

    Bulk-heterojunction (BHJ) organic photovoltaics (OPV) are promising thin-film renewable energy conversion options due to low production cost by high-throughput roll-to-roll manufacturing, an expansive list of compatible materials, and flexible device fabrication.

  19. Effect of Initial Bulk Material Composition on Thermoelectric Properties of Bi2Te3 Thin Films

    NASA Astrophysics Data System (ADS)

    Budnik, A. V.; Rogacheva, E. I.; Pinegin, V. I.; Sipatov, A. Yu.; Fedorov, A. G.

    2013-07-01

    V2VI3 compounds and solid solutions based on them are known to be the best low-temperature thermoelectric (TE) materials. The predicted possibility of enhancement of the TE figure of merit in two-dimensional (2D) structures has stimulated studies of the properties of these materials in the thin-film state. The goal of the present work is to study the dependences of the Seebeck coefficient S, electrical conductivity σ, Hall coefficient R H, charge carrier mobility μ H, and TE power factor P = S 2 σ of Bi2Te3 thin films on the composition of the initial bulk material used for preparing them. Thin films with thickness d = 200 nm to 250 nm were grown by thermal evaporation in vacuum of stoichiometric Bi2Te3 crystals (60.0 at.% Te) and of crystals with 62.8 at.% Te onto glass substrates at temperatures T S of 320 K to 500 K. It was established that the conductivity type of the initial material is reproduced in films fairly well. For both materials, an increase in T S leads to an increase in the thin-film structural perfection, better correspondence between the film composition and that of the initial material, and increase in S, R H, μ H, σ, and P. The room-temperature maximum values of P for the films grown from crystals with 60.0 at.% and 62.8 at.% Te are P = 7.5 × 10-4 W/K2 m and 35 × 10-4 W/K2 m, respectively. Thus, by using Bi2Te3 crystals with different stoichiometry as initial materials, one can control the conductivity type and TE parameters of the films, applying a simple and low-cost method of thermal evaporation from a single source.

  20. Subsurface defect of amorphous carbon film imaged by near field acoustic microscopy

    NASA Astrophysics Data System (ADS)

    Zeng, J. T.; Zhao, K. Y.; Zeng, H. R.; Song, H. Z.; Zheng, L. Y.; Li, G. R.; Yin, Q. R.

    2008-05-01

    Amorphous carbon films were examined by low frequency scanning-probe acoustic microscopy (LF-SPAM). Local elastic properties as well as topography were imaged in the acoustic mode. Two kinds of subsurface defects were revealed by the LF-SPAM method. The influence of the subsurface defects on the elastic properties was also discussed. The ability to image subsurface defects was dependent on the scan area and the scan speed. Our results showed that the low frequency scanning-probe acoustic microscopy is a useful method for imaging subsurface defects with high resolution.

  1. Semicylindrical acoustic transducer from a dielectric elastomer film with compliant electrodes.

    PubMed

    Sugimoto, Takehiro; Ono, Kazuho; Ando, Akio; Morita, Yuichi; Hosoda, Kosuke; Ishii, Daisaku

    2011-08-01

    A semicylindrical acoustic transducer was constructed using a dielectric elastomer film with compliant electrodes that is an electroactive polymer composed of a polyurethane elastomer base and polyethylene dioxythiophene/polystyrene sulfonate electrodes. The use of this dielectric elastomer is advantageous because polyurethane is a common material that keeps its shape without any rigid frame. Because the dielectric elastomer films are essentially incompressible, electric-field-induced thickness changes are usually translated into much larger changes of the film area and side length. Here it is proposed that this change in side length can be utilized for sound generation when the film is bent into a semicylindrical shape. Accordingly, a semicylindrical acoustic transducer was fabricated using a film of thickness of 300 μm and its acoustic characteristics were investigated. The transducer can be operated at low applied voltages by reducing the film thickness, as long as the film is thick enough to generate sufficient force to overcome sound radiation impedance. The second harmonic distortion of the transducer was also investigated as a function of the ratio of the direct current bias voltage to the alternating current audio signal amplitude.

  2. Magnetic resonance study of bulk and thin film EuTiO3

    NASA Astrophysics Data System (ADS)

    Laguta, V. V.; Kamba, S.; Maryško, M.; Andrzejewski, B.; Kachlík, M.; Maca, K.; Lee, J. H.; Schlom, D. G.

    2017-03-01

    Magnetic resonance spectra of EuTiO3 in both bulk and thin film form were taken at temperatures from 3–350 K and microwave frequencies from 9.2–9.8 and 34 GHz. In the paramagnetic phase, magnetic resonance spectra are determined by magnetic dipole and exchange interactions between Eu2+ spins. In the film, a large contribution arises from the demagnetization field. From detailed analysis of the linewidth and its temperature dependence, the parameters of spin–spin interactions were determined: the exchange frequency is 10.5 GHz and the estimated critical exponent of the spin correlation length is  ≈0.4. In the bulk samples, the spectra exhibited a distinct minimum in the linewidth at the Néel temperature, T N  ≈  5.5 K, while the resonance field practically does not change even on cooling below T N. This is indicative of a small magnetic anisotropy ~320 G in the antiferromagnetic phase. In the film, the magnetic resonance spectrum is split below T N into several components due to excitation of the magnetostatic modes, corresponding to a non-uniform precession of magnetization. Moreover, the film was observed to degrade over two years. This was manifested by an increase of defects and a change in the domain structure. The saturated magnetization in the film, estimated from the magnetic resonance spectrum, was about 900 emu cm‑3 or 5.5 µ B/unit cell at T  =  3.5 K.

  3. Comparative AFM nanoscratching tests in air of bulk copper and electrogenerated cuprous oxide films

    NASA Astrophysics Data System (ADS)

    Chaal, Lila; Debiemme-Chouvy, Catherine; Deslouis, Claude; Maurin, Georges; Pailleret, Alain; Saidani, Boualem

    2011-01-01

    The normal and lateral spring constants of rectangular silicon AFM cantilevers bearing pyramidal silicon tips were accurately calibrated using a procedure that takes into account their tilt compared to horizontal orientation and their trapezoidal cross section. Such systems were used to carry out nanoscratching tests in air on technical substrates presenting a moderate roughness (RMS ≈ 40 nm) and made either from bulk copper or from cuprous oxide thin films electrogenerated on copper. The various events occurring during these nanoscratching procedures were characterized in details. In particular, the features of the scars appearing on the scratched zones and SEM observations of the AFM tips used during the nanoscratching procedures are described and exploited to establish a better understanding of the effects of the nanoscratching procedures on the targeted samples. In the case of electrodeposited Cu 2O films, these effects are discussed with the help of chemical and structural characterizations using XPS and XRD studies. All this set of information is used i) to describe the history of the nanoscratching tests and ii) to compare mechanical resistance of bulk copper and electrogenerated Cu 2O thin films using these nanoscratching tests carried out in air. The wear mechanism occurring during nanoscratching tests is discussed for both kinds of samples and compared with the one observed during erosion in erosion-corrosion tests.

  4. Transient gratings in thin films and bulk azo-dye-containing poly(methyl methacrylate) matrix

    NASA Astrophysics Data System (ADS)

    Luo, Duanbin; Lu, Wei; Wu, Shuizhu

    2005-02-01

    Using holographic recording technology, two kinds of transient diffraction gratings were demonstrated in azo-dye doped Poly(methyl methacrylate) (PMMA) films and bulk matrices respectively. In PMMA films containing azo-dye Disperse Red 13 (DR13), the refractive index gratings came from the reorientation of azo-dye molecules in different areas with different polarization distribution of recording beams. The characteristics of the transient gratings in films samples which were recorded by two mutually parallel polarization beams (PP and SS) as well as orthogonal linear polarization beams (PS and +/-45°) from an Ar ion laser (514nm) were investigated by monitoring the first order diffraction intensity of the readout He-Ne laser beam (632.8nm). With the interaction of bi-photonic lights at 514nm and 632.8nm, the transient gratings in azo-dye DR13 doped PMMA bulk matrices was a kind of population gratings of Trans and Cis isomers, which was attributed to the weak absorption of Cis isomers at 632.8nm and the positive dichroism of Trans isomers at 514nm. Furthermore, the all-optical switching behavior of the two kinds of transient holographic gratings were observed repeatedly by turning on and off the writing beams, and a response time at the magnitude of ten milliseconds order could be obtained.

  5. Spectroscopic imaging of photopotentials and photoinduced potential fluctuations in a bulk heterojunction solar cell film.

    PubMed

    Luria, Justin L; Hoepker, Nikolas; Bruce, Robert; Jacobs, Andrew R; Groves, Chris; Marohn, John A

    2012-11-27

    We present spatially resolved photovoltage spectra of a bulk heterojunction solar cell film composed of phase-separated poly(9,9'-dioctylfluorene-co-benzothiadiazole) (F8BT) and poly(9,9'-dioctylfluorene-co-bis-N,N'-(4-butylphenyl)-bis-N,N'-phenyl-1,4-phenylenediamine) (PFB) polymers prepared on ITO/PEDOT:PSS and aluminum substrates. Over both PFB- and F8BT-rich domains, the photopotential spectra were found to be proportional to a linear combination of the polymers' absorption spectra. Charge trapping in the film was studied using photopotential fluctuation spectroscopy, in which low-frequency photoinduced electrostatic potential fluctuations were measured by observing noise in the oscillation frequency of a nearby charged atomic force microscope cantilever. Over both F8BT- and PFB-rich regions, the magnitude, distance dependence, frequency dependence, and illumination wavelength dependence of the observed cantilever frequency noise are consistent with photopotential fluctuations arising from stochastic light-driven trapping and detrapping of charges in F8BT. Taken together, our findings suggest a microscopic mechanism by which intermixing of phases leads to charge trapping and thereby to suppressed open-circuit voltage and decreased efficiency in this prototypical bulk heterojunction solar cell film.

  6. Frequency-domain Harman technique for rapid characterization of bulk and thin film thermoelectric materials

    NASA Astrophysics Data System (ADS)

    Moran, Samuel

    Nanostructured thermoelectrics, often in the form of thin films, may potentially improve the generally poor efficiency of bulk thermoelectric power generators and coolers. In order to characterize the efficiency of these new materials it is necessary to measure their thermoelectric figure of merit, ZT. The only direct measurement of ZT is based on the Harman technique and relies on measuring the voltage drop across a sample subjected to a passing continuous current. Application of this technique to thin films is currently carried out as a time-domain measurement of the voltage as the thermal component decays after switching off an applied voltage. This work develops a technique for direct simultaneous measurement of figure of merit and Seebeck coefficient from the harmonic response of a thermoelectric material under alternating current excitation. A thermocouple mounted on the top surface measures voltage across the device as the frequency of the applied voltage is varied. A thermal model allows the sample thermal conductivity to also be determined and shows good agreement with measurements. This technique provides improved signal-to-noise ratio and accuracy compared to time-domain ZT measurements for comparable conditions while simultaneously measuring Seebeck coefficient. The technique is applied to both bulk and thin film thermoelectric samples.

  7. Method for the determination of bulk and interface density of states in thin-film transistors

    SciTech Connect

    Lui, O. K. B.; Tam, S. W.-B.; Migliorato, P.; Shimoda, T.

    2001-06-01

    In this article we present a method for the accurate determination of interface and bulk density of states (DOS) in thin-film transistors (TFTs), based on the combined analysis of transfer (I{sub D}{endash}V{sub GS}) and capacitance{endash}voltage characteristics. This analysis has achieved a number of results, eliminating sources of inaccuracies that are known to be present in other methods. A procedure for the determination of the electron and hole flatband conductances and bulk Fermi energy is demonstrated. A recursive procedure is employed to extract the bulk DOS directly from Poisson{close_quote}s equation. The advantages of this method are the greater immunity to noise from the original data, the use of the complete Fermi function (no 0 K approximation), and the applicability to thin active layers. This method yields the interface state density spectrum as well as the bulk DOS. This information is very important for device design, process characterization, and modeling of TFTs. {copyright} 2001 American Institute of Physics.

  8. Effect of the photoreaction solvent on surface and bulk properties of poly(lactic acid) and poly(hydroxyalkanoate) films.

    PubMed

    Rasal, Rahul M; Bohannon, Bradley G; Hirt, Douglas E

    2008-05-01

    The major objective of this research was to modify the surface properties of poly(lactic acid) (PLA) and poly(hydroxyalkanoate) (PHA) films by using a sequential two-step photografting approach. In step 1, benzophenone was photografted on the film surface and in step 2, hydrophilic monomers acrylamide and acrylic acid were photopolymerized from the film surfaces. Another objective was to study the effect of the reaction solvent in step 2 on surface and bulk properties of these films. ATR-FTIR spectroscopy and water contact angle goniometry were used to characterize the resultant film surfaces. When ethanol was used as the solvent in step 2, there was significant penetration of the monomers into the films, and bulk properties such as toughness and percent elongation at break were drastically affected. The penetration of these monomers into the bulk was characterized using transmission FTIR microspectroscopy. Microtomed sections of the surface-modified films were placed in a diamond compression cell to perform the FTIR microspectroscopic analyses. The observed monomer penetration into the films was successfully reduced by using water instead of ethanol in step 2, and resultant films showed higher toughness and percent elongation at break than films surface-modified using ethanol as a solvent in step 2.

  9. Nickel Alloy Primary Water Bulk Surface and SCC Corrosion Film Analytical Characterization and SCC Mechanistic Implications

    SciTech Connect

    Morton, D.; Lewis, N.; Hanson, M.; Rice, S.; Sanders, P.

    2007-04-18

    Alloy 600 corrosion coupon tests were performed: (1) to quantify the temperature dependency of general corrosion and (2) to characterize the composition and structure of bulk surface corrosion films for comparison with ongoing primary water SCC (PWSCC) crack tip corrosion film analyses. Results suggest that the thermal activation energy of Alloy 600 corrosion is consistent with the thermal activation energy of nickel alloy PWSCC. Analytical investigations of the structure and composition of Alloy 600 bulk surface corrosion oxides revealed a duplex (inner and outer) oxide layer structure. The outer layer is discontinuous and comprised of relatively large (1 to 3 {micro}m) nickel ferrite crystals and smaller ({approx}0.1 {micro}m) chromium containing nickel ferrite crystals. The inner layer consists of a relatively continuous chromite spinel (major phase) and chromia (Cr{sub 2}O{sub 3} minor phase) which formed through non-selective oxidation. Chromia and dealloyed Alloy 600 (highly Ni enriched metal) were only observed at 337 C (640 F) and only along the boundaries of deformation induced fine grains and subcells. Specimens having deformation free surfaces exhibited continuous uniform inner chromite spinel oxide layers. Specimens with machining induced surface deformation produced non-uniform inner layer oxides (chromite spinel, Cr{sub 2}O{sub 3} and unoxidized material). PWSCC crack tip oxides, in contrast, were fine grain (no duplex structure) and consisted of both chromium rich spinels and ''NiO'' structure oxides. Generally, nickel rich oxides were more abundant under more oxidized conditions (reduced coolant hydrogen) and spinel rich crack tip oxides were favored under more reducing conditions (increased coolant hydrogen). Bulk surface corrosion film thickness did not correlate with observed SCC growth rates. These results suggest that corrosion is not the rate controlling step of PWSCC but rather that PWSCC and corrosion have a common rate controlling sub

  10. Self Assembled Spin Coated and Bulk Films of a Novel Polydiacetylene as Second Order NLO Polymers

    DTIC Science & Technology

    1994-05-31

    T Code: 4132016 W.H. Kim, B. Bihari, R. Moody, N. B. Kodali , J.KumarS.K. Dr. JoAnn Milliken Tripathy. 7. PHI-OUHMING OFH-NIZATION NAMIE(S) AND...Self Assembled Spin Coated and Bulk Films of a Novel Polydiacetylene as Second Order NLO Polymers by W.H. Kim, B. Bihari, R. Moody, N. B. Kodali ...POLYMERS W. H. Kim, B. Bihari+, R. Moody+, N. B. Kodali , J. Kumar+, and S. K. Tripathy, University of Massachusetts-Lowell, Center for Advanced Materials

  11. High-performance flexible thin-film transistors exfoliated from bulk wafer.

    PubMed

    Zhai, Yujia; Mathew, Leo; Rao, Rajesh; Xu, Dewei; Banerjee, Sanjay K

    2012-11-14

    Mechanically flexible integrated circuits (ICs) have gained increasing attention in recent years with emerging markets in portable electronics. Although a number of thin-film-transistor (TFT) IC solutions have been reported, challenges still remain for the fabrication of inexpensive, high-performance flexible devices. We report a simple and straightforward solution: mechanically exfoliating a thin Si film containing ICs. Transistors and circuits can be prefabricated on bulk silicon wafer with the conventional complementary metal-oxide-semiconductor (CMOS) process flow without additional temperature or process limitations. The short channel MOSFETs exhibit similar electrical performance before and after exfoliation. This exfoliation process also provides a fast and economical approach to producing thinned silicon wafers, which is a key enabler for three-dimensional (3D) silicon integration based on Through Silicon Vias (TSVs).

  12. Near field acoustic holography measurements of carbon nanotube thin film speakers.

    PubMed

    Asgarisabet, Mahsa; Barnard, Andrew R; Bouman, Troy M

    2016-12-01

    Carbon nanotube (CNT) thin film speakers produce sound with the thermoacoustic effect. Better understanding of the physical acoustic properties of these speakers will drive future design improvements. Measuring acoustic properties at the surface of the CNT thin film is difficult because the films, themselves, do not vibrate, are fragile and have a high surface temperature. In order to measure the surface particle velocity and sound pressure level (SPL), near field acoustic holography (NAH) has been used by employing probe microphones. NAH images the acoustic quantities of the source system using the set of acoustic pressure measurements on a hologram parallel to the source surface. It is shown that the particle velocity at the surface of an open-air, double-sided speaker is nominally zero, as expected. However, the SPL distribution is not uniform on the source surface, contrary to common lumped parameter model assumptions. Also, particle velocity and sound intensity distributions on the hologram have been obtained in this study. Finally, measured directivity patterns of the planar CNT speaker are reported.

  13. Bulk and compound-specific isotopic characterisation of illicit heroin and cling film.

    PubMed

    Idoine, Fay A; Carter, James F; Sleeman, Richard

    2005-01-01

    Comparative analysis involves various but complementary methods and can be used for forensic intelligence purposes to group seizures of heroin into batches. Much forensic analysis now combines expertise in the traditional area of drugs investigation with a detailed understanding of supply, packaging, distribution, and drugs intelligence. It was the intention of this research to determine whether illicit heroin seizures and packaging material can be grouped according to isotopic compositions, and to explore factors that affect the isotopic compositions. In order to achieve these aims, 14 samples of seized heroin, thirteen provided by Avon and Somerset Constabulary (UK), were analysed by elemental analysis/isotope ratio mass spectrometry (EA/IRMS) and gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) for carbon and hydrogen isotopes. These tests elucidated that a combination of the delta13C, delta15N, delta18O and delta2H results from EA/IRMS is able to distinguish between most samples of bulk heroin. We speculate that the delta13C values of the alkaloids, obtained by GC/C/IRMS, give indications of different geographical or temporal origins of some of the heroin samples. GC/C/IRMS of the cutting agent, caffeine, provides a means to link dilution events. Fifteen retail cling film samples and seven cling film samples from heroin seizures were analysed by EA/IRMS. A multivariate comparison of the carbon, hydrogen and oxygen isotope ratios was able to distinguish between most of the samples. This technique enabled the cling films from the heroin to be grouped according to seizure. Three solvents were tested on two samples of cling film of known composition. Methanol and chloroform were both found to extract material from PVC and from non-PVC cling films. Water-treated PVC was indistinguishable from the untreated PVC and thus water was found to be the most suitable solvent when washing cling film prior to IRMS analysis.

  14. Nonlinear optical observation of coherent acoustic Dirac plasmons in thin-film topological insulators

    PubMed Central

    Glinka, Yuri D.; Babakiray, Sercan; Johnson, Trent A.; Holcomb, Mikel B.; Lederman, David

    2016-01-01

    Low-energy collective electronic excitations exhibiting sound-like linear dispersion have been intensively studied both experimentally and theoretically for a long time. However, coherent acoustic plasmon modes appearing in time-domain measurements are rarely observed due to Landau damping by the single-particle continua. Here we report on the observation of coherent acoustic Dirac plasmon (CADP) modes excited in indirectly (electrostatically) opposite-surface coupled films of the topological insulator Bi2Se3. Using transient second-harmonic generation, a technique capable of independently monitoring the in-plane and out-of-plane electron dynamics in the films, the GHz-range oscillations were observed without corresponding oscillations in the transient reflectivity. These oscillations were assigned to the transverse magnetic and transverse electric guided CADP modes induced by the evanescent guided Lamb acoustic waves and remained Landau undamped due to fermion tunnelling between the opposite-surface Dirac states. PMID:27687867

  15. Nonlinear optical observation of coherent acoustic Dirac plasmons in thin-film topological insulators

    NASA Astrophysics Data System (ADS)

    Glinka, Yuri D.; Babakiray, Sercan; Johnson, Trent A.; Holcomb, Mikel B.; Lederman, David

    2016-09-01

    Low-energy collective electronic excitations exhibiting sound-like linear dispersion have been intensively studied both experimentally and theoretically for a long time. However, coherent acoustic plasmon modes appearing in time-domain measurements are rarely observed due to Landau damping by the single-particle continua. Here we report on the observation of coherent acoustic Dirac plasmon (CADP) modes excited in indirectly (electrostatically) opposite-surface coupled films of the topological insulator Bi2Se3. Using transient second-harmonic generation, a technique capable of independently monitoring the in-plane and out-of-plane electron dynamics in the films, the GHz-range oscillations were observed without corresponding oscillations in the transient reflectivity. These oscillations were assigned to the transverse magnetic and transverse electric guided CADP modes induced by the evanescent guided Lamb acoustic waves and remained Landau undamped due to fermion tunnelling between the opposite-surface Dirac states.

  16. AlScN thin film based surface acoustic wave devices with enhanced microfluidic performance

    NASA Astrophysics Data System (ADS)

    Wang, W. B.; Fu, Y. Q.; Chen, J. J.; Xuan, W. P.; Chen, J. K.; Wang, X. Z.; Mayrhofer, P.; Duan, P. F.; Bittner, A.; Schmid, U.; Luo, J. K.

    2016-07-01

    This paper reports the characterization of scandium aluminum nitride (Al1-x Sc x N, x  =  27%) films and discusses surface acoustic wave (SAW) devices based on them. Both AlScN and AlN films were deposited on silicon by sputtering and possessed columnar microstructures with (0 0 0 2) crystal orientation. The AlScN/Si SAW devices showed improved electromechanical coupling coefficients (K 2, ~2%) compared with pure AlN films (<0.5%). The performance of the two types of devices was also investigated and compared, using acoustofluidics as an example. The AlScN/Si SAW devices achieved much lower threshold powers for the acoustic streaming and pumping of liquid droplets, and the acoustic streaming and pumping velocities were 2  ×  and 3  ×  those of the AlN/Si SAW devices, respectively. Mechanical characterization showed that the Young’s modulus and hardness of the AlN film decreased significantly when Sc was doped, and this was responsible for the decreased acoustic velocity and resonant frequency, and the increased temperature coefficient of frequency, of the AlScN SAW devices.

  17. Characterization of Homopolymer and Polymer Blend Films by Phase Sensitive Acoustic Microscopy

    NASA Astrophysics Data System (ADS)

    Ngwa, Wilfred; Wannemacher, Reinhold; Grill, Wolfgang

    2003-03-01

    CHARACTERIZATION OF HOMOPOLYMER AND POLYMER BLEND FILMS BY PHASE SENSITIVE ACOUSTIC MICROSCOPY W Ngwa, R Wannemacher, W Grill Institute of Experimental Physics II, University of Leipzig, 04103 Leipzig, Germany Abstract We have used phase sensitive acoustic microscopy (PSAM) to study homopolymer thin films of polystyrene (PS) and poly (methyl methacrylate) (PMMA), as well as PS/PMMA blend films. We show from our results that PSAM can be used as a complementary and highly valuable technique for elucidating the three-dimensional (3D) morphology and micromechanical properties of thin films. Three-dimensional image acquisition with vector contrast provides the basis for: complex V(z) analysis (per image pixel), 3D image processing, height profiling, and subsurface image analysis of the polymer films. Results show good agreement with previous studies. In addition, important new information on the three dimensional structure and properties of polymer films is obtained. Homopolymer film structure analysis reveals (pseudo-) dewetting by retraction of droplets, resulting in a morphology that can serve as a starting point for the analysis of polymer blend thin films. The outcome of confocal laser scanning microscopy studies, performed on the same samples are correlated with the obtained results. Advantages and limitations of PSAM are discussed.

  18. The design and flight test of an engine inlet bulk acoustic liner

    NASA Technical Reports Server (NTRS)

    Lester, H. C.; Preisser, J. S.; Parrott, T. L.

    1983-01-01

    This paper summarizes the design, fabrication and flight evaluation of a Kevlar acoustic liner configuration for a JT15D turbofan engine. The liner was designed to suppress, by a measurable amount, a dominant (13,0) BPF tone. This tone or spinning mode was produced for research purposes by installing 41 circumferentially distributed small diameter rods upstream of the 28 fan blades. Duct liner attenuations calculated by a finite element procedure were compared to far field power (insertion) losses deduced from flight data. The finite element program modeled the variable geometry of the JT15D inlet and used a uniform flow with a boundary layer roll-off to model the inlet flow field. Calculated liner losses were generally conservative. That is, measured far field power losses were generally greater than attenuations calculated by the finite element computer program.

  19. Bulk and surface acoustic waves in solid-fluid Fibonacci layered materials.

    PubMed

    Quotane, I; El Boudouti, E H; Djafari-Rouhani, B; El Hassouani, Y; Velasco, V R

    2015-08-01

    We study theoretically the propagation and localization of acoustic waves in quasi-periodic structures made of solid and fluid layers arranged according to a Fibonacci sequence. We consider two types of structures: either a given Fibonacci sequence or a periodic repetition of a given sequence called Fibonacci superlattice. Various properties of these systems such as: the scaling law and the self-similarity of the transmission spectra or the power law behavior of the measure of the energy spectrum have been highlighted for waves of sagittal polarization in normal and oblique incidence. In addition to the allowed modes which propagate along the system, we study surface modes induced by the surface of the Fibonacci superlattice. In comparison with solid-solid layered structures, the solid-fluid systems exhibit transmission zeros which can break the self-similarity behavior in the transmission spectra for a given sequence or induce additional gaps other than Bragg gaps in a periodic structure.

  20. Translational diffusion across a free-standing smectic film above the bulk smectic-A -isotropic transition temperature

    NASA Astrophysics Data System (ADS)

    Śliwa, Izabela; Zakharov, A. V.

    2017-01-01

    Calculations of translational self-diffusion coefficient in free-standing smectic films during a series of layer-thinning transitions as the temperature is raised above the bulk smectic-A -isotropic transition have been carried out. A molecular model based upon the random walk theory is applied for calculating the translational diffusion coefficient (TDC) D∥ across the smectic film both in the bulk of the film, as well as in the vicinity of the bounding surfaces. Calculations of D∥ require the set of the orientational and translational order parameters (OPs) which have been obtained by using the extended McMillan approach with anisotropic forces. The effect of E on the orientational and translational OPs, as well as on the TDC of smectic films has been investigated. A reasonable agreement between the theoretically predicted and the experimentally obtained data on the TDC in the bulk of the partially fluorinated H10F5MOPP film has been obtained. We also found, in agreement with the experimentally observed behavior of D∥(N )(N =25 ,13 ,11 ,10 ) , that the translational diffusion coefficient in the bulk of the film gradually increases as the film thickness N is decreased.

  1. Translational diffusion across a free-standing smectic film above the bulk smectic-A-isotropic transition temperature.

    PubMed

    Śliwa, Izabela; Zakharov, A V

    2017-01-01

    Calculations of translational self-diffusion coefficient in free-standing smectic films during a series of layer-thinning transitions as the temperature is raised above the bulk smectic-A-isotropic transition have been carried out. A molecular model based upon the random walk theory is applied for calculating the translational diffusion coefficient (TDC) D_{∥} across the smectic film both in the bulk of the film, as well as in the vicinity of the bounding surfaces. Calculations of D_{∥} require the set of the orientational and translational order parameters (OPs) which have been obtained by using the extended McMillan approach with anisotropic forces. The effect of E on the orientational and translational OPs, as well as on the TDC of smectic films has been investigated. A reasonable agreement between the theoretically predicted and the experimentally obtained data on the TDC in the bulk of the partially fluorinated H10F5MOPP film has been obtained. We also found, in agreement with the experimentally observed behavior of D_{∥}(N)(N=25,13,11,10), that the translational diffusion coefficient in the bulk of the film gradually increases as the film thickness N is decreased.

  2. Efficient bulk heterojunction photovoltaic cells using small-molecular-weight organic thin films.

    PubMed

    Peumans, Peter; Uchida, Soichi; Forrest, Stephen R

    2003-09-11

    The power conversion efficiency of small-molecular-weight and polymer organic photovoltaic cells has increased steadily over the past decade. This progress is chiefly attributable to the introduction of the donor-acceptor heterojunction that functions as a dissociation site for the strongly bound photogenerated excitons. Further progress was realized in polymer devices through use of blends of the donor and acceptor materials: phase separation during spin-coating leads to a bulk heterojunction that removes the exciton diffusion bottleneck by creating an interpenetrating network of the donor and acceptor materials. The realization of bulk heterojunctions using mixtures of vacuum-deposited small-molecular-weight materials has, on the other hand, posed elusive: phase separation induced by elevating the substrate temperature inevitably leads to a significant roughening of the film surface and to short-circuited devices. Here, we demonstrate that the use of a metal cap to confine the organic materials during annealing prevents the formation of a rough surface morphology while allowing for the formation of an interpenetrating donor-acceptor network. This method results in a power conversion efficiency 50 per cent higher than the best values reported for comparable bilayer devices, suggesting that this strained annealing process could allow for the formation of low-cost and high-efficiency thin film organic solar cells based on vacuum-deposited small-molecular-weight organic materials.

  3. A lightweight push-pull acoustic transducer composed of a pair of dielectric elastomer films.

    PubMed

    Sugimoto, Takehiro; Ando, Akio; Ono, Kazuho; Morita, Yuichi; Hosoda, Kosuke; Ishii, Daisaku; Nakamura, Kentaro

    2013-11-01

    A lightweight push-pull acoustic transducer using dielectric elastomer films was proposed for use in advanced audio systems in homes. The push-pull structure consists of two dielectric elastomer films developed to serve as an electroactive polymer. The transducer utilizes the change in the surface area of the dielectric elastomer film, induced by an electric-field-induced change in the thickness, for sound generation. The resonance frequency of the transducer was derived from modeling the push-pull configuration to estimate the lower limit of the frequency range. Measurement results presented an advantage of push-pull driving in the suppression of harmonic distortion.

  4. Mass variation of a thin liquid film driven by an acoustic wave

    SciTech Connect

    Batson, W.; Agnon, Y.; Oron, A.

    2015-06-15

    In this work, we investigate the dynamics of a thin liquid film subjected to an acoustic field in its bounding vapor space. For large acoustic wavelengths, the field imposes a spatially uniform, temporally periodic temperature and pressure at the vapor side of the film interface, which leads to a periodic driving force for mass exchange with the vapor. Neglecting the dynamics of the vapor space, we adopt the “one-sided” model for evaporation/condensation of thin liquid films. In the interest of determining the effect of oscillatory mass exchange on film stability, we consider films in thermodynamic equilibrium with the mean vapor conditions. The effects of oscillatory phase change on both linear stability and nonlinear dynamics are investigated for slightly inclined ceiling films that are destabilized by gravity and subject to thermocapillary effects. At linear order, this mass exchange is not found to alter the band of unstable wave numbers and only marginally affects the growth rates. Additionally, the mass exchanged during evaporation is balanced by condensation so that the total mass of the liquid film is conserved. However, due to nonlinear effects, we find that traveling waves encouraged by the inclination are subject to net mass loss. It is then found that normal thermocapillary effects enhance this loss, and that anomalous thermocapillarity mitigates or even reverses the loss to a mass gain.

  5. Mass variation of a thin liquid film driven by an acoustic wave

    NASA Astrophysics Data System (ADS)

    Batson, W.; Agnon, Y.; Oron, A.

    2015-06-01

    In this work, we investigate the dynamics of a thin liquid film subjected to an acoustic field in its bounding vapor space. For large acoustic wavelengths, the field imposes a spatially uniform, temporally periodic temperature and pressure at the vapor side of the film interface, which leads to a periodic driving force for mass exchange with the vapor. Neglecting the dynamics of the vapor space, we adopt the "one-sided" model for evaporation/condensation of thin liquid films. In the interest of determining the effect of oscillatory mass exchange on film stability, we consider films in thermodynamic equilibrium with the mean vapor conditions. The effects of oscillatory phase change on both linear stability and nonlinear dynamics are investigated for slightly inclined ceiling films that are destabilized by gravity and subject to thermocapillary effects. At linear order, this mass exchange is not found to alter the band of unstable wave numbers and only marginally affects the growth rates. Additionally, the mass exchanged during evaporation is balanced by condensation so that the total mass of the liquid film is conserved. However, due to nonlinear effects, we find that traveling waves encouraged by the inclination are subject to net mass loss. It is then found that normal thermocapillary effects enhance this loss, and that anomalous thermocapillarity mitigates or even reverses the loss to a mass gain.

  6. Dynamic fluid-film interferometry as a predictor of bulk foam properties.

    PubMed

    Frostad, John M; Tammaro, Daniele; Santollani, Luciano; Bochner de Araujo, Simone; Fuller, Gerald G

    2016-11-23

    Understanding and enabling the control of the properties of foams is important for a variety of commercial processes and consumer products. In these systems, the role of surface active compounds has been the subject of many investigations using a wide range of techniques. The study of their influence on simplified geometries such as two bubbles in a liquid or a thin film of solution (such as in the well-known Scheludko cell), has yielded important fundamental understanding. Similarly, in this work an interferometric technique is used to study the dynamic evolution of the film formed by a single bubble being pressed against a planar air-liquid interface. Here interferometry is used to dynamically measure the total volume of liquid contained within the thin-film region between the bubble and the planar interface. Three different small-molecule, surfactant solutions were investigated and the data obtained via interferometry were compared to measurements of the density of bulk foams of the same solutions. The density measurements were collected with a simple, but novel technique using a conical-shaped bubbling apparatus. The results reveal a strong correlation between the measurements on single bubbles and complete foams. This suggests that further investigations using interferometric techniques can be instrumental to building a more detailed mechanistic understanding of how different surface-active compounds influence foam properties. The results also reveal that the commonly used assumption that surfactant-laden interfaces may be modeled as immobile, is too simplistic to accurately model interfaces with small-molecule surfactants.

  7. Structural Relaxations in Bulk and Thin Film Polymers: Role of Macromolecular Architecture

    NASA Astrophysics Data System (ADS)

    Green, Peter

    2014-03-01

    Structural relaxations that occur in polymers quenched below the glass transition temperature, Tg, are responsible for time-dependent changes in physical properties that include optical, specific volume and the enthalpy. This phenomenon, physical aging, has been of interest in bulk polymers for decades and much is understood. The aging rate, R, is known to increase as the temperature at which the glass ages, T' , decreases below Tg, due to the increasing departure from structural equilibrium; it then decreases with further decreases in T. We show that the aging rates of star-shaped polymers are slower than their linear analogs of the same degree of polymerization, N. Whereas the temperature dependence of R is independent of N for linear chains, it depends on the functionality, f , and on the degree of polymerization per arm, N', of the star-shaped macromolecules. R decreases with increasing f , for N' less than a threshold degree of polymerization, which increases with increasing f. The aging of very thin films (h ~ 100 nm) is dependent on the distance, z, from an external interface. With the use positron annihilation spectroscopy (PALS) we determined the z-dependence of the Tg in thin films and showed that the aging rate is largely determined by the difference between the local glass transition temperature of the films and T'. Finally we show that the aging rates of linear and star-shaped macromolecules are consistent with experimental findings of glassy dynamics in both systems.

  8. The effects of changing deposition conditions on the similarity of sputter-deposited fluorocarbon thin films to bulk PTFE

    NASA Astrophysics Data System (ADS)

    Zandona, Philip

    Solid lubrication of space-borne mechanical components is essential to their survival and the continued human exploration of space. Recent discoveries have shown that PTFE when blended with alumina nanofillers exhibits greatly improved physical performance properties, with wear rates being reduced by several orders of magnitude. The bulk processes used to produce the PTFE-alumina blends are limiting. Co-sputter deposition of PTFE and a filler material overcomes several of these limitations by enabling the reduction of particle size to the atomic level and also by allowing for the even coating of the solid lubricant on relatively large areas and components. The goal of this study was to establish a baseline performance of the sputtered PTFE films as compared to the bulk material, and to establish deposition conditions that would result in the most bulk-like film possible. In order to coax change in the structure of the sputtered films, sputtering power and deposition temperature were increased independently. Further, post-deposition annealing was applied to half of the deposited film in an attempt to affect change in the film structure. Complications in the characterization process due to increasing film thickness were also examined. Bulk-like metrics for characterization processes the included Fourier transform infrared spectroscopy (FTIR), X-ray spectroscopy (XPS), nanoindentation via atomic force microscopy, and contact angle of water on surface measurements were established. The results of the study revealed that increasing sputtering power and deposition temperature resulted in an increase in the similarity between the fluorocarbon films and the bulk PTFE, at a cost of affecting the potential of the film thicknesses, either by affecting the deposition process directly, or by decreasing the longevity of the sputtering targets.

  9. Surface acoustic wave velocity of gold films deposited on silicon substrates at different temperatures

    SciTech Connect

    Salas, E.; Jimenez Rioboo, R. J.; Prieto, C.; Every, A. G.

    2011-07-15

    Au thin films have been deposited by DC magnetron sputtering on Si (001) substrates at different substrate temperatures, ranging from 200 K to 450 K. With increasing temperature, the expected crystallinity and morphology of the Au thin film are clearly improved, as shown by x ray diffraction, atomic force microscopy and scanning electron microscopy experiments. Parallel to this, the surface acoustic wave propagation velocity shows a clear enhancement toward the ideal values obtained from numerical simulations of a Au thin film on Si (001) substrate. Moreover, a very thin and slightly rough interlayer between the Si (001) substrate and the Au thin film is developed for temperatures above 350 K. The composition and nature of this interlayer is not known. This interlayer may be responsible for the steep change in the structural and elastic properties of the Au thin films at the higher temperatures and possibly also for an improvement of the adhesion properties of the Au on the Si (001) substrate.

  10. Growth and characterization of zinc oxide and PZT films for micromachined acoustic wave devices

    NASA Astrophysics Data System (ADS)

    Yoon, Sang Hoon

    The ability to detect the presence of low concentrations of harmful substances, such as biomolecular agents, warfare agents, and pathogen cells, in our environment and food chain would greatly advance our safety, provide more sensitive tools for medical diagnostics, and protect against terrorism. Acoustic wave (AW) devices have been widely studied for such applications due to several attractive properties, such as rapid response, reliability, portability, ease of use, and low cost. The principle of these sensors is based on a fundamental feature of the acoustic wave that is generated and detected by a piezoelectric material. The performance of the device, therefore, greatly depends on the properties of piezoelectric thin film. The required properties include a high piezoelectric coefficient and high electromechanical coefficients. The surface roughness and the mechanical properties, such as Young's modulus and hardness, are also factors that can affect the wave propagation of the device. Since the film properties are influenced by the structure of the material, understanding thin film structure is very important for the design of high-performance piezoelectric MEMS devices for biosensor applications. In this research, two piezoelectric thin film materials were fabricated and investigated. ZnO films were fabricated by CSD (Chemical Solution Deposition) and sputtering, and PZT films were fabricated by CSD only. The process parameters for solution derived ZnO and PZT films, such as the substrate type, the effect of the chelating agent, and heat treatment, were studied to find the relationship between process parameters and thin film structure. In the case of the sputtered ZnO films, the process gas types and their ratio, heat treatment in situ, and post deposition were investigated. The key results of systematic experiments show that the combined influence of chemical modifiers and substrates in chemical solution deposition have an effect on the crystallographic

  11. Hydrogen in tin dioxide films and bulk ceramics: An attempt to identify the most hidden impurity

    SciTech Connect

    Watanabe, Ken; Hashiguchi, Minako; Sakaguchi, Isao; Bryant, Alex Adachi, Yutaka; Zhen, Yuhua Ohgaki, Takeshi; Ohsawa, Takeo; Haneda, Hajime; Ohashi, Naoki

    2014-01-27

    Hydrogen impurities in SnO{sub 2} films and bulk ceramics were investigated in terms of mass transport and electron transport. The hydrogen concentration (n[H]) in these samples was found to be 10{sup 19} cm{sup −3} or higher. Further increase in n[H] could be achieved by annealing the samples in a humid atmosphere. The isotope tracer ({sup 1}H/{sup 2}H exchange) study revealed that a part of the hydrogen in these samples showed rapid migration even at 300 °C. However, electrical measurements revealed that the electron concentration in the samples was much less than n[H]. These results could be explained by assuming the presence of defect-hydrogen complexes.

  12. Wavelength-Versatile Graphene-Gold Film Saturable Absorber Mirror for Ultra-Broadband Mode-Locking of Bulk Lasers

    PubMed Central

    Ma, Jie; Xie, Guoqiang; Lv, Peng; Gao, Wenlan; Yuan, Peng; Qian, Liejia; Griebner, Uwe; Petrov, Valentin; Yu, Haohai; Zhang, Huaijin; Wang, Jiyang

    2014-01-01

    An ultra-broadband graphene-gold film saturable absorber mirror (GG-SAM) with a spectral coverage exceeding 1300 nm is experimentally demonstrated for mode-locking of bulk solid-state lasers. Owing to the p-type doping effect caused by graphene-gold film interaction, the graphene on gold-film substrate shows a remarkably lower light absorption relative to pristine graphene, which is very helpful to achieve continuous-wave mode-locking in low-gain bulk lasers. Using the GG-SAM sample, stable mode-locking is realized in a Yb:YCOB bulk laser near 1 μm, a Tm:CLNGG bulk laser near 2 μm and a Cr:ZnSe bulk laser near 2.4 μm. The saturable absorption is characterised at an intermediate wavelength of 1.56 μm by pump-probe measurements. The as-fabricated GG-SAM with ultra-broad bandwidth, ultrafast recovery time, low absorption, and low cost has great potential as a universal saturable absorber mirror for mode-locking of various bulk lasers with unprecedented spectral coverage. PMID:24853072

  13. A perfectly stoichiometric and flat CeO2(111) surface on a bulk-like ceria film

    PubMed Central

    Barth, C.; Laffon, C.; Olbrich, R.; Ranguis, A.; Parent, Ph.; Reichling, M.

    2016-01-01

    In surface science and model catalysis, cerium oxide (ceria) is mostly grown as an ultra-thin film on a metal substrate in the ultra-high vacuum to understand fundamental mechanisms involved in diverse surface chemistry processes. However, such ultra-thin films do not have the contribution of a bulk ceria underneath, which is currently discussed to have a high impact on in particular surface redox processes. Here, we present a fully oxidized ceria thick film (180 nm) with a perfectly stoichiometric CeO2(111) surface exhibiting exceptionally large, atomically flat terraces. The film is well-suited for ceria model studies as well as a perfect substitute for CeO2 bulk material. PMID:26879800

  14. A perfectly stoichiometric and flat CeO2(111) surface on a bulk-like ceria film

    NASA Astrophysics Data System (ADS)

    Barth, C.; Laffon, C.; Olbrich, R.; Ranguis, A.; Parent, Ph.; Reichling, M.

    2016-02-01

    In surface science and model catalysis, cerium oxide (ceria) is mostly grown as an ultra-thin film on a metal substrate in the ultra-high vacuum to understand fundamental mechanisms involved in diverse surface chemistry processes. However, such ultra-thin films do not have the contribution of a bulk ceria underneath, which is currently discussed to have a high impact on in particular surface redox processes. Here, we present a fully oxidized ceria thick film (180 nm) with a perfectly stoichiometric CeO2(111) surface exhibiting exceptionally large, atomically flat terraces. The film is well-suited for ceria model studies as well as a perfect substitute for CeO2 bulk material.

  15. A perfectly stoichiometric and flat CeO2(111) surface on a bulk-like ceria film.

    PubMed

    Barth, C; Laffon, C; Olbrich, R; Ranguis, A; Parent, Ph; Reichling, M

    2016-02-16

    In surface science and model catalysis, cerium oxide (ceria) is mostly grown as an ultra-thin film on a metal substrate in the ultra-high vacuum to understand fundamental mechanisms involved in diverse surface chemistry processes. However, such ultra-thin films do not have the contribution of a bulk ceria underneath, which is currently discussed to have a high impact on in particular surface redox processes. Here, we present a fully oxidized ceria thick film (180 nm) with a perfectly stoichiometric CeO2(111) surface exhibiting exceptionally large, atomically flat terraces. The film is well-suited for ceria model studies as well as a perfect substitute for CeO2 bulk material.

  16. Magnetic domain walls in bulk and thin film Fe: first principles noncollinear magnetism study

    NASA Astrophysics Data System (ADS)

    Nakamura, K.; Takeda, Y.; Akiyama, T.; Ito, T.; Freeman, A. J.

    2004-03-01

    We investigate the electronic and magnetic structures of domain walls in ferromagnetic Fe bulk and Fe(110) monolayer by using the first-principles FLAPW method(Wimmer, Krakauer, Weinert and Freeman, PRB 24, 864(1981)) including noncollinear magnetism with no shape approximation of the magnetization density.(Nakamura, Freeman, Wang, Zhong, and Fernandez-de-Castro, PRB 65, 12402 (2002); 67, 14420 (2003)) In the bulk case, the self-consistent LSDA results demonstrate that the magnetic moments change continuously from one orientation to another as seen in a Bloch wall, and reveal that the formation energy of the domain wall significantly decreases when the domain wall thickness increases, as expected from phenomenological theory. The domain walls in thin film behave very differently: Surprisingly, the magnetic moment directions change rapidly; thus the wall width is only about 8 ÅThis consists and supports the atomically sharp domain wall in Fe/W(110) by the recently proposed SP-STM measurements.(Pratzer, Elmers, Bode, Pietzsch, Kubetzka and Wiesendanger, PRL 87, 127201 (2001))

  17. A laser probe based on a Sagnac interferometer with fast mechanical scan for RF surface and bulk acoustic wave devices.

    PubMed

    Hashimoto, Ken-ya; Kashiwa, Keiskue; Wu, Nan; Omori, Tatsuya; Yamaguchi, Masatsune; Takano, Osamu; Meguro, Sakae; Akahane, Koichi

    2011-01-01

    This paper describes the development of a phasesensitive laser probe with fast mechanical scan for RF surface and bulk acoustic wave (SAW/BAW) devices. The Sagnac interferometer composed of micro-optic elements was introduced for the selective detection of RF vertical motion associated with RF SAW/BAW propagation and vibration. A high-pass characteristic of the interferometer makes the measurement very insensitive to low-frequency vibration. This feature allows us to apply the fast mechanical scan to the interferometric measurement without badly sacrificing its SNR and spatial resolution. The system was applied to the visualization of a field pattern on the vibrating surface of an RF BAW resonator operating in the 2 GHz range. The field pattern was obtained in 17 min as a 2-D image (500 × 750 pixel with 0.4 μm resolution and SNR of 40 dB). The system was also applied to the characterization of an RF SAW resonator operating in the 1 GHz range, and the applicability of the system was demonstrated.

  18. Frequency flicker of 2.3 GHz AlN-sapphire high-overtone bulk acoustic resonators

    NASA Astrophysics Data System (ADS)

    Boudot, Rodolphe; Martin, Gilles; Friedt, Jean-Michel; Rubiola, Enrico

    2016-12-01

    We report the detailed characterization of 2.3 GHz AlN-Sapphire high-overtone bulk acoustic resonators (HBARs), with a typical loaded Q-factor of 25-30 × 103, 15-20 dB insertion loss, and resonances separated by about 10 MHz. The temperature coefficient of frequency of HBARs is measured to be about -25 ppm/K. We observe at high-input microwave power a significant distortion of the HBAR resonance lineshape, attributed to non-linear effects. The power-induced fractional frequency variation of the HBAR resonance is measured to be about -5 × 10-10/μW. The residual phase noise of a HBAR is measured in the range of -110 to -130 dBrad2/Hz at 1 Hz Fourier frequency, yielding resonator fractional frequency fluctuations at the level of -205 to -225 dB/Hz at 1 Hz and an ultimate HBAR-limited oscillator Allan deviation about 7 × 10-12 at 1 s integration time. The 1/f noise of the HBAR resonator is found to increase with the input microwave power. A HBAR resonator is used for the development of a low phase noise 2.3 GHz oscillator. An absolute phase noise of -60, -120, and -145 dBrad2/Hz for offset frequencies of 10 Hz, 1 kHz, and 10 kHz, respectively, in excellent agreement with the Leeson effect, is measured.

  19. Biotin-streptavidin binding interactions of dielectric filled silicon bulk acoustic resonators for smart label-free biochemical sensor applications.

    PubMed

    Heidari, Amir; Yoon, Yong-Jin; Park, Woo-Tae; Su, Pei-Chen; Miao, Jianmin; Lin, Julius Tsai Ming; Park, Mi Kyoung

    2014-03-07

    Sensor performance of a dielectric filled silicon bulk acoustic resonator type label-free biosensor is verified with biotin-streptavidin binding interactions as a model system. The mass sensor is a micromachined silicon square plate with a dielectric filled capacitive excitation mechanism. The resonance frequency of the biotin modified resonator decreased 315 ppm when exposed to streptavidin solution for 15 min with a concentration of 10(-7) M, corresponding to an added mass of 3.43 ng on the resonator surface. An additional control is added by exposing a bovine serum albumin (BSA)-covered device to streptavidin in the absence of the attached biotin. No resonance frequency shift was observed in the control experiment, which confirms the specificity of the detection. The sensor-to-sensor variability is also measured to be 4.3%. Consequently, the developed sensor can be used to observe in biotin-streptavidin interaction without the use of labelling or molecular tags. In addition, biosensor can be used in a variety of different immunoassay tests.

  20. Biotin-Streptavidin Binding Interactions of Dielectric Filled Silicon Bulk Acoustic Resonators for Smart Label-Free Biochemical Sensor Applications

    PubMed Central

    Heidari, Amir; Yoon, Yong-Jin; Park, Woo-Tae; Su, Pei-Chen; Miao, Jianmin; Lin, Julius Tsai Ming; Park, Mi Kyoung

    2014-01-01

    Sensor performance of a dielectric filled silicon bulk acoustic resonator type label-free biosensor is verified with biotin-streptavidin binding interactions as a model system. The mass sensor is a micromachined silicon square plate with a dielectric filled capacitive excitation mechanism. The resonance frequency of the biotin modified resonator decreased 315 ppm when exposed to streptavidin solution for 15 min with a concentration of 10−7 M, corresponding to an added mass of 3.43 ng on the resonator surface. An additional control is added by exposing a bovine serum albumin (BSA)-covered device to streptavidin in the absence of the attached biotin. No resonance frequency shift was observed in the control experiment, which confirms the specificity of the detection. The sensor-to-sensor variability is also measured to be 4.3%. Consequently, the developed sensor can be used to observe in biotin-streptavidin interaction without the use of labelling or molecular tags. In addition, biosensor can be used in a variety of different immunoassay tests. PMID:24608003

  1. Crystal structure and electronic properties of bulk and thin film brownmillerite oxides.

    SciTech Connect

    Young, Joshua; Rondinelli, James M.

    2015-11-17

    The equilibrium structure and functional properties exhibited by brownmillerite oxides, a family of perovskitederived structures with alternating layers of BO6 octahedra and BO4 tetrahedra, viz., ordered arrangements of oxygen vacancies, is dependent on a variety of competing crystal-chemistry factors. We use electronic structure calculations to disentangle the complex interactions in two ferrates, Sr2Fe2O5 and Ca2Fe2O5, relating the stability of the equilibrium (strain-free) and thin film structures to both previously identified and herein newly proposed descriptors.We show that cation size and intralayer separation of the tetrahedral chains provide key contributions to the preferred ground state. We show the bulk ground-state structure is retained in the ferrates over a range of strain values; however, a change in the orientation of the tetrahedral chains, i.e., a perpendicular orientation of the vacancies relative to the substrate, is stabilized in the compressive region. The structure stability under strain is largely governed by maximizing the intraplane separation of the dipoles generated from rotations of the FeO4 tetrahedra. Lastly, we find that the electronic band gap is strongly influenced by strain, manifesting as an unanticipated asymmetric-vacancy alignment dependent response. This atomistic understanding establishes a practical route for the design of functional electronic materials in thin film geometries.

  2. Effect of film nanostructure on in-plane charge transport in organic bulk heterojunction materials

    NASA Astrophysics Data System (ADS)

    Danielson, Eric; Ooi, Zi-En; Dodabalapur, Ananth

    2013-09-01

    Bulk heterojunction (BHJ) organic solar cells are a promising alternative energy technology, but a thorough understanding of charge transport behavior in BHJ materials is necessary in order to design devices with high power conversion efficiencies. Parameters such as carrier mobilities, carrier concentrations, and the recombination coefficient have traditionally been successfully measured using vertical structures similar to organic photovoltaic (OPV) cells. We have developed a lateral BHJ device which complements these vertical techniques by allowing spatially resolved measurement along the transport direction of charge carriers. This is essential for evaluating the effect of nanoscale structure and morphology on these important charge transport parameters. Nanomorphology in organic BHJ films has been controlled using a variety of methods, but the effect of these procedures has been infrequently correlated with the charge transport parameter of the BHJ material. Electron beam lithography has been used to create lateral device structures with many voltage probes at a sub-micron resolution throughout the device channel. By performing in-situ potentiometry, we can calculate both carrier mobilities and determine the effect of solvent choice and annealing procedure on the charge transport in BHJ system. Spin coated P3HT:PCBM films prepared from solutions in chloroform and o-xylene are characterized using this technique.

  3. Understanding of DNA directed nanoparticle superlattices in bulk and thin film

    NASA Astrophysics Data System (ADS)

    Lee, Byeongdu

    Over the years, there have been significant advances in assembling nanoparticles with DNA into superlattices. Since the first reports on DNA directed FCC and BCC superlattices consisting of single type of spherical nanoparticles, building blocks for the DNA-nanoparticle superlattices have been extended from a spherical gold nanoparticle to various types of other particles including quantum dots, magnetic, hollow, or polyhedral particles. Not only single component, but superlattices of binary and ternary components have also been synthesized. Although still many details are unclear, now there is a general consensus about thermodynamics of this type of assembly, which led us to fabricate thin films of DNA directed nanoparticle superlattices on substrate for applications such as optical materials. Since the structures are formed in aqueous condition, small angle x-ray scattering (SAXS) that does not disturb the system has been a critical tool to determine structural and thermodynamic characteristics of the assemblies. Thus, we have also been improving SAXS instrumentations and computational methods to calculate scattering profiles for the nanoparticle superlattices. In this talk, we will summarize our works with a focus on some structural details of these superlattices and DNA and understanding about the role of DNA in the crystallization processes in bulk and thin film.

  4. Accurate characterization of SiO2 thin films using surface acoustic waves.

    PubMed

    Knapp, Matthias; Lomonosov, Alexey M; Warkentin, Paul; Jäger, Philipp M; Ruile, Werner; Kirschner, Hans-Peter; Honal, Matthias; Bleyl, Ingo; Mayer, Andreas P; Reindl, Leonhard M

    2015-04-01

    We have investigated the acoustic properties of silicon dioxide thin films. Therefore, we determined the phase velocity dispersion of LiNbO3 substrate covered with SiO2 deposited by a plasma enhanced chemical vapor deposition and a physical vapor deposition (PVD) process using differential delay lines and laser ultrasonic method. The density p and the elastic constants (c11 and c44) can be extracted by fitting corresponding finite element simulations to the phase velocities within an accuracy of at least +4%. Additionally, we propose two methods to improve the accuracy of the phase velocity determination by dealing with film thickness variation of the PVD process.

  5. Feasibility study of detection of dielectric breakdown of gate oxide film by using acoustic emission method

    NASA Astrophysics Data System (ADS)

    Kasashima, Yuji; Tabaru, Tatsuo; Uesugi, Fumihiko

    2016-12-01

    An in situ detection method for the dielectric breakdown of oxide films for MOS gates has been required in the plasma etching process. In this feasibility study, a conventional MOSFET device is used and an acoustic emission (AE) method is employed for the detection of the dielectric breakdown of a gate oxide film. A thin type AE sensor is attached at the backside of an electrostatic chuck (ESC), and the dielectric breakdown in a MOSFET, which is set on the ESC, is detected. The results demonstrate that the thin type AE sensor can detect the dielectric breakdown with an energy on the order of µJ.

  6. Hybrid Surface Acoustic Wave- Electrohydrodynamic Atomization (SAW-EHDA) For the Development of Functional Thin Films

    PubMed Central

    Choi, Kyung Hyun; Kim, Hyun Bum; Ali, Kamran; Sajid, Memoon; Uddin Siddiqui, Ghayas; Chang, Dong Eui; Kim, Hyung Chan; Ko, Jeong Beom; Dang, Hyun Woo; Doh, Yang Hoi

    2015-01-01

    Conventional surface acoustic wave - electrostatic deposition (SAW-ED) technology is struggling to compete with other thin film fabrication technologies because of its limitation in atomizing high density solutions or solutions with strong inter-particle bonding that requires very high frequency (100 MHz) and power. In this study, a hybrid surface acoustic wave - electrohydrodynamic atomization (SAW-EHDA) system has been introduced to overcome this problem by integrating EHDA with SAW to achieve the deposition of different types of conductive inks at lower frequency (19.8 MHZ) and power. Three materials, Poly [2-methoxy-5-(2-ethylhexyloxy)-1, 4-phenylenevinylene] (MEH-PPV), Zinc Oxide (ZnO), and Poly(3, 4-ethylenedioxythiophene):Polystyrene Sulfonate (PEDOT:PSS) have been successfully deposited as thin films through the hybrid SAW-EHDA. The films showed good morphological, chemical, electrical, and optical characteristics. To further evaluate the characteristics of deposited films, a humidity sensor was fabricated with active layer of PEDOT:PSS deposited using the SAW-EHDA system. The response of sensor was outstanding and much better when compared to similar sensors fabricated using other manufacturing techniques. The results of the device and the films’ characteristics suggest that the hybrid SAW-EHDA technology has high potential to efficiently produce wide variety of thin films and thus predict its promising future in certain areas of printed electronics. PMID:26478189

  7. Quantitative and high spatial resolution d{sub 33} measurement of piezoelectric bulk and thin films

    SciTech Connect

    Shetty, Smitha Yang, Jung In; Trolier-McKinstry, Susan; Stitt, Joe

    2015-11-07

    A single beam laser interferometer based on a modified Mirau detection scheme with a vertical resolution of ∼5 pm was developed for localized d{sub 33} measurements on patterned piezoelectric films. The tool provides high spatial resolution (∼2 μm), essential for understanding scaling and processing effects in piezoelectric materials. This approach enables quantitative information on d{sub 33}, currently difficult in local measurement techniques such as piezoresponse force microscopy. The interferometer is built in a custom microscope and employs a phase lock-in technique in order to detect sub-Angstrom displacements. d{sub 33} measurements on single crystal 0.67PbMg{sub 0.33}Nb{sub 0.67}O{sub 3}-0.33PbTiO{sub 3} and bulk PbZrTiO{sub 3}-5A ceramics demonstrated agreement within <3% with measurements using a double beam laser interferometer. Substrate bending contributions to out-of-plane strain, observed in thin continuous PbZr{sub 0.52}Ti{sub 0.48}O{sub 3} films grown on Si substrates is reduced for electrode diameters smaller than 100 μm. Direct scanning across room temperature and 150 °C poled 5 μm and 10 μm features etched in 0.5 μm thick PbZr{sub 0.52}Ti{sub 0.48}O{sub 3} films doped with 1% Nb confirmed minimal substrate contributions to the effective d{sub 33,f}. Furthermore, enhanced d{sub 33,f} values were observed along the feature edges due to partial declamping from the substrate, thus validating the application of single beam interferometry on finely patterned electrodes.

  8. Quantitative and high spatial resolution d33 measurement of piezoelectric bulk and thin films

    NASA Astrophysics Data System (ADS)

    Shetty, Smitha; Yang, Jung In; Stitt, Joe; Trolier-McKinstry, Susan

    2015-11-01

    A single beam laser interferometer based on a modified Mirau detection scheme with a vertical resolution of ˜5 pm was developed for localized d33 measurements on patterned piezoelectric films. The tool provides high spatial resolution (˜2 μm), essential for understanding scaling and processing effects in piezoelectric materials. This approach enables quantitative information on d33, currently difficult in local measurement techniques such as piezoresponse force microscopy. The interferometer is built in a custom microscope and employs a phase lock-in technique in order to detect sub-Angstrom displacements. d33 measurements on single crystal 0.67PbMg0.33Nb0.67O3-0.33PbTiO3 and bulk PbZrTiO3-5A ceramics demonstrated agreement within <3% with measurements using a double beam laser interferometer. Substrate bending contributions to out-of-plane strain, observed in thin continuous PbZr0.52Ti0.48O3 films grown on Si substrates is reduced for electrode diameters smaller than 100 μm. Direct scanning across room temperature and 150 °C poled 5 μm and 10 μm features etched in 0.5 μm thick PbZr0.52Ti0.48O3 films doped with 1% Nb confirmed minimal substrate contributions to the effective d33,f. Furthermore, enhanced d33,f values were observed along the feature edges due to partial declamping from the substrate, thus validating the application of single beam interferometry on finely patterned electrodes.

  9. Surface-acoustic-wave device incorporating conducting Langmuir-Blodgett films

    NASA Astrophysics Data System (ADS)

    Holcroft, B.; Roberts, G. G.; Barraud, A.; Richard, J.

    1987-04-01

    Surface-acoustic-wave devices incorporating conducting Langmuir-Blodgett films are reported for the first time. Excellent characteristics have been obtained using a mixed valence charge transfer salt of a substituted pyridinium tetracyanoquinodimethane. The control afforded by the deposition technique has enabled the fractional change in surface wave velocity due to the electrical effects to be distinguished from those due to mass loading. The resistivity of the organic surface layer is measured to be 2 ohm-cm.

  10. Finite element model of surface acoustic wave method for mechanical characterization of patterned thin films of the ultra-large scaled integrated interconnect.

    PubMed

    Xiao, Xia; Shan, Xingmeng; Tao, Ye; Sun, Yuan; Kikkawa, Takamaro

    2013-02-01

    Surface acoustic waves (SAWs) technique is a promising method to determine the mechanical properties of thin low dielectric constant (low-k) dielectrics by matching the experimental dispersion curve with the theoretical dispersion curves. However, it is difficult to calculate the dispersion curves when SAWs propagate along patterned structure. In this paper, finite element method (FEM) is applied to obtain the numerical dispersion results of SAWs propagating on patterned film. Periodic boundary condition and plane-strain model is used to improve the computation speed. Four structures of bulk silicon, single layered low-k film, two layered Cu and SiO2 film, and patterned film, are simulated in this paper. The dispersion curves of single low-k films derived from the FEM simulation agree very well with those calculated by traditional method, which verifies the correct employment of the FEM approach. Dispersion curves of two patterned film structure of Cu and SiO2 with difference metal wire width are obtained. Effective Young's moduli are achieved by fitting the FEM simulated results with those of traditional theoretical calculation through least square error method.

  11. Transitions between paraelectric and ferroelectric phases of bent-core smectic liquid crystals in the bulk and in thin freely suspended films

    NASA Astrophysics Data System (ADS)

    Eremin, Alexey; Floegel, Martin; Kornek, Ulrike; Stern, Stephan; Stannarius, Ralf; Nádasi, Hajnalka; Weissflog, Wolfgang; Zhu, Chenhui; Shen, Yongqiang; Park, Cheol Soo; Maclennan, Joseph; Clark, Noel

    2012-11-01

    We report on the contrasting phase behavior of a bent-core liquid crystal with a large opening angle between the mesogenic units in the bulk and in freely suspended films. Second-harmonic generation experiments and direct observation of director inversion walls in films in an applied electric field reveal that the nonpolar smectic C phase observed in bulk samples becomes a ferroelectric “banana” phase in films, showing that a mesogen with a small steric moment can give a phase with polar order in freely suspended films even when the corresponding bulk phase is paraelectric.

  12. Effect of viscoelastic film for shear horizontal surface acoustic wave on quartz

    NASA Astrophysics Data System (ADS)

    Goto, Mikihiro; Yatsuda, Hiromi; Kondoh, Jun

    2015-07-01

    A numerical analysis for the mass loading sensitivity of shear horizontal surface acoustic wave (SH-SAW) immunoassay biosensors on quartz has already been studied. However, the mass loading analysis is insufficient to explain the actual biosensor performance. To understand the SH-SAW biosensor performance, we analyze the effect of a viscoelastic film on SH-SAW biosensors. In this paper, a numerical analysis using a simple viscoelastic model for the SH-SAW biosensors is presented. In the theoretical model, the bioreaction layer on the SH-SAW biosensors can be treated as a viscoelastic film. The velocity changes of the 250 MHz SH-SAWs on quartz substrates, which are covered with bovine serum albumin (BSA) layers of different thicknesses, were measured and compared with the theoretical results obtained using the proposed viscoelastic model. Good agreement of the velocity changes of SH-SAWs versus changes in the viscoelastic film thickness between theoretical and experimental results was obtained.

  13. Influence of the side chain and substrate on polythiophene thin film surface, bulk, and buried interfacial structures.

    PubMed

    Xiao, Minyu; Jasensky, Joshua; Zhang, Xiaoxian; Li, Yaoxin; Pichan, Cayla; Lu, Xiaolin; Chen, Zhan

    2016-08-10

    The molecular structures of organic semiconducting thin films mediate the performance of various devices composed of such materials. To fully understand how the structures of organic semiconductors alter on substrates due to different polymer side chains and different interfacial interactions, thin films of two kinds of polythiophene derivatives with different side-chains, poly(3-hexylthiophene) (P3HT) and poly(3-potassium-6-hexanoate thiophene) (P3KHT), were deposited and compared on various surfaces. A combination of analytical tools was applied in this research: contact angle goniometry and X-ray photoelectron spectroscopy (XPS) were used to characterize substrate dielectric surfaces with varied hydrophobicity for polymer film deposition; X-ray diffraction and UV-vis spectroscopy were used to examine the polythiophene film bulk structure; sum frequency generation (SFG) vibrational spectroscopy was utilized to probe the molecular structures of polymer film surfaces in air and buried solid/solid interfaces. Both side-chain hydrophobicity and substrate hydrophobicity were found to mediate the crystallinity of the polythiophene film, as well as the orientation of the thiophene ring within the polymer backbone at the buried polymer/substrate interface and the polymer thin film surface in air. For the same type of polythiophene film deposited on different substrates, a more hydrophobic substrate surface induced thiophene ring alignment with the surface normal at both the buried interface and on the surface in air. For different films (P3HT vs. P3KHT) deposited on the same dielectric substrate, a more hydrophobic polythiophene side chain caused the thiophene ring to align more towards the surface at the buried polymer/substrate interface and on the surface in air. We believe that the polythiophene surface, bulk, and buried interfacial molecular structures all influence the hole mobility within the polythiophene film. Successful characterization of an organic conducting

  14. Mossbauer studies of bulk and thin-film FeTe

    NASA Technical Reports Server (NTRS)

    Aggarwal, K.; Escue, W. T.; Mendiratta, R. G.

    1978-01-01

    In study, dependence of Mossbauer parameters on film thickness and film substrate was measured and related to iron tellurium structure. Report also describes film deposition technique (flash deposition) and Mossbauer apparatus.

  15. Impact of lattice dynamics on the phase stability of metamagnetic FeRh: Bulk and thin films

    NASA Astrophysics Data System (ADS)

    Wolloch, M.; Gruner, M. E.; Keune, W.; Mohn, P.; Redinger, J.; Hofer, F.; Suess, D.; Podloucky, R.; Landers, J.; Salamon, S.; Scheibel, F.; Spoddig, D.; Witte, R.; Roldan Cuenya, B.; Gutfleisch, O.; Hu, M. Y.; Zhao, J.; Toellner, T.; Alp, E. E.; Siewert, M.; Entel, P.; Pentcheva, R.; Wende, H.

    2016-11-01

    We present phonon dispersions, element-resolved vibrational density of states (VDOS) and corresponding thermodynamic properties obtained by a combination of density functional theory (DFT) and nuclear resonant inelastic x-ray scattering (NRIXS) across the metamagnetic transition of B2 FeRh in the bulk material and thin epitaxial films. We see distinct differences in the VDOS of the antiferromagnetic (AF) and ferromagnetic (FM) phases, which provide a microscopic proof of strong spin-phonon coupling in FeRh. The FM VDOS exhibits a particular sensitivity to the slight tetragonal distortions present in epitaxial films, which is not encountered in the AF phase. This results in a notable change in lattice entropy, which is important for the comparison between thin film and bulk results. Our calculations confirm the recently reported lattice instability in the AF phase. The imaginary frequencies at the X point depend critically on the Fe magnetic moment and atomic volume. Analyzing these nonvibrational modes leads to the discovery of a stable monoclinic ground-state structure, which is robustly predicted from DFT but not verified in our thin film experiments. Specific heat, entropy, and free energy calculated within the quasiharmonic approximation suggest that the new phase is possibly suppressed because of its relatively smaller lattice entropy. In the bulk phase, lattice vibrations contribute with the same sign and in similar magnitude to the isostructural AF-FM phase transition as excitations of the electronic and magnetic subsystems demonstrating that lattice degrees of freedom need to be included in thermodynamic modeling.

  16. Acoustic study of a linear low-density polyethylene film after modification of the crystalline structure by heating.

    PubMed

    Tohmyoh, Hironori; Sakamoto, Yuhei

    2014-02-01

    We report on a hybrid microscopy technique that enables us to measure the acoustic properties of a thin polymer film together with an optical microscope image of the corresponding area. Linear low-density polyethylene films are heated to various temperatures and examined by the technique. Density of the film is increased by heating and its sound velocity is decreased compared with a film without heating. Also, spherulites can clearly be seen in the optical microscope image, supporting the thermal shrinkage of the film which can be detected by the present technique.

  17. Pulsed laser deposition of epitaxial yttrium iron garnet films with low Gilbert damping and bulk-like magnetization

    SciTech Connect

    Onbasli, M. C. Kim, D. H.; Ross, C. A.; Kehlberger, A.; Jakob, G.; Kläui, M.; Chumak, A. V.; Hillebrands, B.

    2014-10-01

    Yttrium iron garnet (YIG, Y {sub 3}Fe{sub 5}O{sub 12}) films have been epitaxially grown on Gadolinium Gallium Garnet (GGG, Gd{sub 3}Ga{sub 5}O{sub 12}) substrates with (100) orientation using pulsed laser deposition. The films were single-phase, epitaxial with the GGG substrate, and the root-mean-square surface roughness varied between 0.14 nm and 0.2 nm. Films with thicknesses ranging from 17 to 200 nm exhibited low coercivity (<2 Oe), near-bulk room temperature saturation moments (∼135 emu cm{sup −3}), in-plane easy axis, and damping parameters as low as 2.2 × 10{sup −4}. These high quality YIG thin films are useful in the investigation of the origins of novel magnetic phenomena and magnetization dynamics.

  18. Mechanical characterization of porous nano-thin films by use of atomic force acoustic microscopy.

    PubMed

    Kopycinska-Müller, M; Clausner, A; Yeap, K-B; Köhler, B; Kuzeyeva, N; Mahajan, S; Savage, T; Zschech, E; Wolter, K-J

    2016-03-01

    The indentation modulus of thin films of porous organosilicate glass with a nominal porosity content of 30% and thicknesses of 350nm, 200nm, and 46nm is determined with help of atomic force acoustic microscopy (AFAM). This scanning probe microscopy based technique provides the highest possible depth resolution. The values of the indentation modulus obtained for the 350nm and 200nm thin films were respectively 6.3GPa±0.2GPa and 7.2GPa±0.2GPa and free of the substrate influence. The sample with the thickness of 46nm was tested in four independent measurement sets. Cantilevers with two different tip radii of about 150nm and less than 50nm were applied in different force ranges to obtain a result for the indentation modulus that was free of the substrate influence. A detailed data analysis yielded value of 8.3GPa±0.4GPa for the thinnest film. The values of the indentation modulus obtained for the thin films of porous organosilicate glasses increased with the decreasing film thickness. The stiffening observed for the porous films could be explained by evolution of the pore topology as a function of the film thickness. To ensure that our results were free of the substrate influence, we analyzed the ratio of the sample deformation as well as the tip radius to the film thickness. The results obtained for the substrate parameter were compared for all the measurement series and showed, which ones could be declared as free of the substrate influence.

  19. Phase transition in bulk single crystals and thin films of VO2 by nanoscale infrared spectroscopy and imaging

    DOE PAGES

    Liu, Mengkun; Sternbach, Aaron J.; Wagner, Martin; ...

    2015-06-29

    We have systematically studied a variety of vanadium dioxide (VO2) crystalline forms, including bulk single crystals and oriented thin films, using infrared (IR) near-field spectroscopic imaging techniques. By measuring the IR spectroscopic responses of electrons and phonons in VO2 with sub-grain-size spatial resolution (~20nm), we show that epitaxial strain in VO2 thin films not only triggers spontaneous local phase separations, but leads to intermediate electronic and lattice states that are intrinsically different from those found in bulk. Generalized rules of strain- and symmetry-dependent mesoscopic phase inhomogeneity are also discussed. Furthermore, these results set the stage for a comprehensive understanding ofmore » complex energy landscapes that may not be readily determined by macroscopic approaches.« less

  20. Determining the bubble cap film thickness of bursting bubbles from their acoustic emissions.

    PubMed

    Deane, Grant B

    2013-02-01

    A study of the sound generated by 2.5 mm radius bubbles bursting on the surface of fresh water is presented. The sound pulses are found to be sensitive to the time interval between the bubble reaching the water surface and bursting. Bubbles that burst within a few 10's of milliseconds behave like a Helmholtz resonator and radiate a swept chirp pulse. Bubbles that persist for 100's of milliseconds or more exhibit more complex acoustic behavior. An analysis of the resonator behavior provides an estimate of the film thickness in reasonable agreement with a fluid drainage model.

  1. A thin film electro-acoustic enzyme biosensor allowing the detection of trace organophosphorus pesticides.

    PubMed

    Chen, Da; Wang, Jingjing; Xu, Yan; Zhang, Luyin

    2012-10-01

    We report an analytical method using a thin film electro-acoustic resonator for the detection of organophosphorus pesticides. The acetylcholinesterase (AChE) enzyme was immobilized on the surface of the resonator. In the presence of organophosphorus compounds, the degree of inhibitory effect of organophosphorus compounds on the AChE activity and the concentration of pesticides were detected in real time by measuring the frequency shift of the resonator. The proposed device has a remarkably low detection limit of 1.8×10(-11)M and obvious advantages such as small size, simple operation, and integrated circuit compatibility, providing a promising tool for pesticide analysis.

  2. Acoustics

    NASA Technical Reports Server (NTRS)

    Goodman, Jerry R.; Grosveld, Ferdinand

    2007-01-01

    The acoustics environment in space operations is important to maintain at manageable levels so that the crewperson can remain safe, functional, effective, and reasonably comfortable. High acoustic levels can produce temporary or permanent hearing loss, or cause other physiological symptoms such as auditory pain, headaches, discomfort, strain in the vocal cords, or fatigue. Noise is defined as undesirable sound. Excessive noise may result in psychological effects such as irritability, inability to concentrate, decrease in productivity, annoyance, errors in judgment, and distraction. A noisy environment can also result in the inability to sleep, or sleep well. Elevated noise levels can affect the ability to communicate, understand what is being said, hear what is going on in the environment, degrade crew performance and operations, and create habitability concerns. Superfluous noise emissions can also create the inability to hear alarms or other important auditory cues such as an equipment malfunctioning. Recent space flight experience, evaluations of the requirements in crew habitable areas, and lessons learned (Goodman 2003; Allen and Goodman 2003; Pilkinton 2003; Grosveld et al. 2003) show the importance of maintaining an acceptable acoustics environment. This is best accomplished by having a high-quality set of limits/requirements early in the program, the "designing in" of acoustics in the development of hardware and systems, and by monitoring, testing and verifying the levels to ensure that they are acceptable.

  3. Electroabsorption modulators based on bulk GaN films and GaN/AlGaN multiple quantum wells

    NASA Astrophysics Data System (ADS)

    Kao, Chen-Kai; Bhattacharyya, Anirban; Thomidis, Christos; Paiella, Roberto; Moustakas, Theodore D.

    2011-04-01

    Ultraviolet electroabsorption modulators based on bulk GaN films and on GaN/AlGaN multiple quantum wells were developed and characterized. In both types of devices, the absorption edge at room temperature is dominated by excitonic effects and can be strongly modified through the application of an external electric field. In the bulk devices, the applied voltage causes a broadening and quenching of the excitonic absorption, leading to enhanced transmission. In the quantum-well devices, the external field partially cancels the built-in polarization-induced electric fields in the well layers, thereby increasing the absorption. Unlike optical modulators based on smaller-bandgap zinc blende semiconductors, the bulk devices here are shown to provide similar performance levels as the quantum well devices, which is mainly a consequence of the uniquely large exciton binding energies of nitride semiconductors.

  4. Crossover between Weak Antilocalization and Weak Localization of Bulk States in Ultrathin Bi2Se3 Films

    NASA Astrophysics Data System (ADS)

    Wang, Huichao; Liu, Haiwen; Chang, Cui-Zu; Zuo, Huakun; Zhao, Yanfei; Sun, Yi; Xia, Zhengcai; He, Ke; Ma, Xucun; Xie, X. C.; Xue, Qi-Kun; Wang, Jian

    2014-07-01

    We report transport studies on the 5 nm thick Bi2Se3 topological insulator films which are grown via molecular beam epitaxy technique. The angle-resolved photoemission spectroscopy data show that the Fermi level of the system lies in the bulk conduction band above the Dirac point, suggesting important contribution of bulk states to the transport results. In particular, the crossover from weak antilocalization to weak localization in the bulk states is observed in the parallel magnetic field measurements up to 50 Tesla. The measured magneto-resistance exhibits interesting anisotropy with respect to the orientation of parallel magnetic field B// and the current I, signifying intrinsic spin-orbit coupling in the Bi2Se3 films. Our work directly shows the crossover of quantum interference effect in the bulk states from weak antilocalization to weak localization. It presents an important step toward a better understanding of the existing three-dimensional topological insulators and the potential applications of nano-scale topological insulator devices.

  5. Crossover between Weak Antilocalization and Weak Localization of Bulk States in Ultrathin Bi2Se3 Films

    PubMed Central

    Wang, Huichao; Liu, Haiwen; Chang, Cui-Zu; Zuo, Huakun; Zhao, Yanfei; Sun, Yi; Xia, Zhengcai; He, Ke; Ma, Xucun; Xie, X. C.; Xue, Qi-Kun; Wang, Jian

    2014-01-01

    We report transport studies on the 5 nm thick Bi2Se3 topological insulator films which are grown via molecular beam epitaxy technique. The angle-resolved photoemission spectroscopy data show that the Fermi level of the system lies in the bulk conduction band above the Dirac point, suggesting important contribution of bulk states to the transport results. In particular, the crossover from weak antilocalization to weak localization in the bulk states is observed in the parallel magnetic field measurements up to 50 Tesla. The measured magneto-resistance exhibits interesting anisotropy with respect to the orientation of parallel magnetic field B// and the current I, signifying intrinsic spin-orbit coupling in the Bi2Se3 films. Our work directly shows the crossover of quantum interference effect in the bulk states from weak antilocalization to weak localization. It presents an important step toward a better understanding of the existing three-dimensional topological insulators and the potential applications of nano-scale topological insulator devices. PMID:25056600

  6. High-frequency surface acoustic wave device based on thin-film piezoelectric interdigital transducers

    SciTech Connect

    Sarin Kumar, A.K.; Paruch, P.; Triscone, J.-M.; Daniau, W.; Ballandras, S.; Pellegrino, L.; Marre, D.; Tybell, T.

    2004-09-06

    Using high-quality epitaxial c-axis Pb(Zr{sub 0.2}Ti{sub 0.8})O{sub 3} films grown by off-axis magnetron sputtering onto metallic (001) Nb-doped SrTiO{sub 3} substrates, a nonconventional thin-film surface acoustic wave device based on periodic piezoelectric transducers was realized. The piezoelectric transducers consist of a series of ferroelectric domains with alternating polarization states. The artificial modification of the ferroelectric domain structure is performed by using an atomic force microscope tip as a source of electric field, allowing local switching of the polarization. Devices with 1.2 and 0.8 {mu}m wavelength, defined by the modulation period of the polarization, and corresponding to central frequencies in the range 1.50-3.50 GHz have been realized and tested.

  7. Evolution of multilayer Ar films on graphite below and above the bulk triple point: a neutron diffraction study

    NASA Astrophysics Data System (ADS)

    Gay, J. M.; Suzanne, J.; Dash, J. G.; Lauter, H. J.

    1991-09-01

    Neutron diffraction is used to study the growth behavior of thin films of argon adsorbed on graphite foam in the temperature range 55.5 K-90.5 K. It is shown that a uniform film is condensed at 65.5 K for thicknesses below 4.5 layers. For higher coverages, bulk crystallites start to grow into capillaries whereas the uniform film grows much more slowly to reach a thickness of 6.4 layers for a total coverage of about 20 statistical layers. A model is presented showing that the capillary condensation probably occurs in conical pores and open corners. At 80.5 K, a liquid-like phase, 1.5 layer thick, is observed revealing the occurrence of surface melting. Above the bulk melting point (T_m=83.8 K), all the bulk crystallites have melted but a solid film is still present on the graphite surface. Its thickness varies from 1 to 3-4 layers depending on total coverage and temperature. The melting temperatures of these solid films are reported. Finally, the uniform solid film is laterally compressed with respect to bulk (111) planes with a continuous relaxation when its thickness increases. On étudie par diffraction de neutrons le mode de croissance de films minces d'argon adsorbé sur de la mousse de graphite (foam) dans la gamme de températures 55,5 K-90,5 K. Un film uniforme est formé à 65,5 K lorsque l'épaisseur est inférieure à 4,5 couches. Pour des recouvrements plus grands, des cristallites commencent à se condenser tandis que le film uniforme continue à croître beaucoup plus lentement jusqu'à une épaisseur de 6,4 couches pour un taux de couverture total d'environ 20 couches statistiques. On présente un modèle qui montre que la condensation capillaire se produit dans des pores coniques et des coins. A 80,5 K, on observe une phase de type liquide de 1,5 couche qui est la signature de la fusion de surface. Au-dessus du point de fusion tridimensionnel (T_m=83,8 K), tous les cristallites ont fondu mais un film solide est toujours présent sur la surface de

  8. Surface acoustic wave ammonia sensor based on ZnO/SiO2 composite film.

    PubMed

    Wang, Shuang-Yue; Ma, Jin-Yi; Li, Zhi-Jie; Su, H Q; Alkurd, N R; Zhou, Wei-Lie; Wang, Lu; Du, Bo; Tang, Yong-Liang; Ao, Dong-Yi; Zhang, Shou-Chao; Yu, Q K; Zu, Xiao-Tao

    2015-03-21

    A surface acoustic wave (SAW) resonator with ZnO/SiO2 (ZS) composite film was used as an ammonia sensor in this study. ZS composite films were deposited on the surface of SAW devices using the sol-gel method, and were characterized using SEM, AFM, and XRD. The performance of the sensors under ammonia gas was optimized by adjusting the molar ratio of ZnO:SiO2 to 1:1, 1:2 and 1:3, and the sensor with the ratio of ZnO to SiO2 equaling to 1:2 was found to have the best performance. The response of sensor was 1.132 kHz under 10 ppm NH3, which was much higher than that of the sensor based on a pristine ZnO film. Moreover, the sensor has good selectivity, reversibility and stability at room temperature. These can be attributed to the enhanced absorption of ammonia and unique surface reaction on composite films due to the existence of silica.

  9. Integration of bulk-quality thin film magneto-optical cerium-doped yttrium iron garnet on silicon nitride photonic substrates.

    PubMed

    Onbasli, Mehmet C; Goto, Taichi; Sun, Xueyin; Huynh, Nathalie; Ross, C A

    2014-10-20

    Cerium substituted yttrium iron garnet (Ce:YIG) films were grown on yttrium iron garnet (YIG) seed layers on silicon nitride films using pulsed laser deposition. Optimal process conditions for forming garnet films on silicon nitride are presented. Bulk or near-bulk magnetic and magneto-optical properties were observed for 160 nm thick Ce:YIG films grown at 640 °C on rapid thermal annealed 40 nm thick YIG grown at 640 °C and 2 Hz pulse rate. The effect of growth temperature and deposition rate on structural, magnetic and magneto-optical properties has been investigated.

  10. Effect of ethanol variation on the internal environment of sol-gel bulk and thin films with aging.

    PubMed

    Gupta, R; Mozumdar, S; Chaudhury, N K

    2005-10-15

    Sol-gel derived bulk and thin films were prepared from different compositions at low pH ( approximately 2.0) containing varying concentrations of ethanol from 15 to 60% at constant water (H(2)O)/tetraethyl-orthosilicate (TEOS) ratio (R=4). The fluorescence microscopic and spectroscopic measurements on fluorescent probe, Hoechst 33258 (H258) entrapped in these compositions were carried out at different days of storage to monitor the effects of concentration of ethanol on the internal environment of sol-gel materials. Fluorescence microscopic observations on sol-gel thin films, prepared by dip coating technique depicted uniform and cracked surface at withdrawal speed 1cm/min (high speed) and 0.1cm/min (low speed) respectively, which did not change during aging. Fluorescence spectral measurements showed emission maximum of H258 at approximately 535 nm in fresh sols at all concentrations of ethanol which depicted slight blue shift to 512 nm during aging in bulk. No such spectral shift has been observed in sol-gel thin films coated at high speed whereas thin films coated at low speed clearly showed an additional band at approximately 404 nm at 45 and 60% concentration of ethanol after about one month of storage. Analysis of the fluorescence lifetime data indicated single exponential decay (1.6-1.8 ns) in fresh sol and from third day onwards, invariably double exponential decay with a short (tau(1)) and a long (tau(2)) component were observed in sol-gel bulk with a dominant tau(1) at approximately 1.2 ns at all concentrations of ethanol. A double exponential decay consisting of a short component (tau(1)) at approximately 0.2 ns and a long component (tau(2)) at approximately 3.5 ns were observed at all ethanol concentrations in both fresh and aged sol-gel thin films. Further, distribution analysis of lifetimes of H258 showed two mean lifetimes with increased width in aged bulk and thin films. These results are likely to have strong implications in designing the internal

  11. Measurement of surface acoustic wave velocity using a variable-line-focus polyurea thin-film ultrasonic transducer.

    PubMed

    Aoyagi, Takahiro; Nakazawa, Marie; Tabaru, Masaya; Nakamura, Kentaro; Ueha, Sadayuki

    2009-08-01

    This paper presents the novel measurement method of the surface acoustic wave velocity by the variable-line- focus transducer using a polyurea piezoelectric ultrasonic transducer. First, a multiresonant polyurea thin-film ultrasonic transducer is fabricated by the vapor deposition polymerization process using 2 monomers. Second, the measurement system of surface acoustic wave velocity modified from the V(z) curve method is established. The system uses the fabricated polyurea thin film as a variable-line-focus transducer at the 30-MHz resonance frequency. The focal length is changed by varying the radius of curvature of the film transducer. To estimate the surface acoustic wave velocities from the measured data theoretically, the photographs of the transducer bent shapes are taken by using a digital microscope, and the bent transducer curvature is modeled by the 7th-order polynomial. To examine the performances of the variable-line-focus transducer, the surface acoustic wave velocities of an aluminum and a synthesized silica glass specimen have been measured. The measured surface acoustic velocities showed good agreement with the reference values.

  12. Pressure probe and hot-film probe rsponses to acoustic excitation in mean flow

    NASA Technical Reports Server (NTRS)

    Parrott, T. L.; Jones, M. G.

    1986-01-01

    An experiment was conducted to compare the relative responses of a hot-film probe and a pressure probe positioned in a flow duct carrying mean flow and progressive acoustic waves. The response of each probe was compared with that of a condenser-type microphone flush mounted in the duct wall for flow Mach numbers up to about 0.5. The response of the pressure probe was less than that of the flush-mounted microphone by not more than about 2.1 dB at the highest centerline Mach number. This decreased response of the probe can likely be attributed to flow-induced impedance changes at the probe sensor orifices. The response of the hot-film probe, expressed in terms of fluctuating pressure, was greater than that of the flush-mounted microphone by as much as 6.0 dB at the two higher centerline Mach numbers. Removal of the contribution from fluctuating temperature in the hot-film analytical model greatly improved the agreement between the two transducer responses.

  13. Preparation of a high-quality PZT thick film with performance comparable to those of bulk materials for applications in MEMS

    NASA Astrophysics Data System (ADS)

    Xu, Xiao-Hui; Chu, Jia-Ru

    2008-06-01

    High-quality lead zirconate titanate (PZT) thick films have been prepared on silicon substrates by combining PZT-Si bonding and wet-etching technology. The bulk PZT wafer was first bonded to the silicon substrate using a 2 µm thick intermediate layer of epoxy resin with a bonding strength higher than 10 MPa. Then the bulk PZT was thinned by a wet-etching method. The thickness of the final PZT films depends on the etching time. The PZT thick films after being polished showed a surface roughness of about 20 nm (RMS), which can satisfy most of the requirements in MEMS. The prepared PZT thick films show a dielectric constant as high as 2400 below 100 kHz, remnant polarization of 13 µC cm-2, piezoelectric constant d31 of about -280 pm V-1 and Young's modulus of about 63 GPa. The measured electromechanical properties of the PZT thick films were comparable to those of the corresponding bulk ceramics. This approach makes it possible to obtain high-quality PZT films because it separates the PZT wafer fabrication from the target substrate and consequently allows integration of the PZT thick films onto many kinds of substrates. Finally, a self-sensing bulk PZT thick film actuator was fabricated as an example of a basic PZT-Si diaphragm structure that can be used in piezoelectric micropumps, and its sensing and actuating performances were also demonstrated.

  14. Comparison between experiment and theory in the temperature variation of film tension above the bulk isotropic transition in free-standing liquid-crystal films.

    PubMed

    Veum, M; Duelge, L; Droske, J; Nguyen, H T; Huang, C C; Mirantsev, L V

    2009-09-01

    Using differential scanning calorimetry, the transition enthalpies and temperatures for the bulk smectic-isotropic phase transition have been measured for a series of liquid-crystal compounds. For five compounds, those values were used as parameters in a microscopic mean-field model to predict the temperature dependence of the difference in free-energy density between a sample of material in a free-standing smectic film and that in the bulk. The model predicts a weak temperature dependence below the bulk clearing point and a pronounced monotonic increase with temperature above the transition temperature. The compounds used in this study were chosen specifically because they were also the subject of a previous independent experimental study [M. Veum, Phys. Rev. E 74, 011703 (2006)] that demonstrated a sudden monotonic increase in the free-standing film tension with temperature, which is qualitatively consistent with the predictions of the above-mentioned mean-field model. This study presents a direct and quantitative comparison between the predictions of the mean-field model and the results from previous tension experiments.

  15. Near-field measurement of ZnS:Mn nanocrystal and bulk thin-film electroluminescent devices.

    PubMed

    Grmela, L; Macku, R; Tomanek, P

    2008-02-01

    A near-field study of the electro-optical phenomena and aging characteristics of nanostructured and bulk ZnS:Mn alternating-current thin-film electro-optical devices is presented. ZnS:Mn nanocrystals embedded in the glass matrices as well as ZnS:Mn thin-film phosphors contain four different concentrations of Mn (from 0.05 to 1.0 mol%). The activator impurity in the phosphor influences the spectral properties and, to a large extent, the temporal properties of optical emission and an aging process of the devices. Therefore, a local photoluminescence and electroluminescence investigation using a scanning near-field optical microscope technique is provided and the aging characteristics of ZnS:Mn nanocrystal structure also presented.

  16. Epitaxial growth of hexagonal tungsten bronze Cs x WO3 films in superconducting phase region exceeding bulk limit

    NASA Astrophysics Data System (ADS)

    Soma, Takuto; Yoshimatsu, Kohei; Ohtomo, Akira

    2016-07-01

    We report epitaxial synthesis of superconducting Cs x WO3 (x = 0.11, 0.20, and 0.31) films on Y-stabilized ZrO2 (111) substrates. The hexagonal crystal structure was verified not only for the composition within the stable region of the bulk (x = 0.20 and 0.31), but also for the out-of-range composition (x = 0.11). The onset of the superconducting transition was recorded at 5.8 K for x = 0.11. We found a strong correlation between the superconducting transition temperature (T C) and the c-axis length, irrespective of the Cs content. These results indicated that the hidden superconducting phase region of hexagonal tungsten bronze is accessible using epitaxial synthesis of lightly doped films.

  17. Micro-particle manipulation by single beam acoustic tweezers based on hydrothermal PZT thick film

    PubMed Central

    Zhu, Benpeng; Xu, Jiong; Li, Ying; Wang, Tian; Xiong, Ke; Lee, Changyang; Yang, Xiaofei; Shiiba, Michihisa; Takeuchi, Shinichi; Zhou, Qifa; Shung, K. Kirk

    2016-01-01

    Single-beam acoustic tweezers (SBAT), used in laboratory-on-a-chip (LOC) device has promising implications for an individual micro-particle contactless manipulation. In this study, a freestanding hydrothermal PZT thick film with excellent piezoelectric property (d33 = 270pC/N and kt = 0.51) was employed for SBAT applications and a press-focusing technology was introduced. The obtained SBAT, acting at an operational frequency of 50MHz, a low f-number (∼0.9), demonstrated the capability to trap and manipulate a micro-particle sized 10μm in the distilled water. These results suggest that such a device has great potential as a manipulator for a wide range of biomedical and chemical science applications. PMID:27014504

  18. Bendable ZnO thin film surface acoustic wave devices on polyethylene terephthalate substrate

    SciTech Connect

    He, Xingli; Guo, Hongwei; Chen, Jinkai; Wang, Wenbo; Xuan, Weipeng; Xu, Yang E-mail: jl2@bolton.ac.uk; Luo, Jikui E-mail: jl2@bolton.ac.uk

    2014-05-26

    Bendable surface acoustic wave (SAW) devices were fabricated using high quality c-axis orientation ZnO films deposited on flexible polyethylene terephthalate substrates at 120 °C. Dual resonance modes, namely, the zero order pseudo asymmetric (A{sub 0}) and symmetric (S{sub 0}) Lamb wave modes, have been obtained from the SAW devices. The SAW devices perform well even after repeated flexion up to 2500 με for 100 times, demonstrating its suitability for flexible electronics application. The SAW devices are also highly sensitive to compressive and tensile strains, exhibiting excellent anti-strain deterioration property, thus, they are particularly suitable for sensing large strains.

  19. Investigation of the full spectrum phonon lifetime in thin silicon films from the bulk spectral phonon mean-free-path distribution by using kinetic theory

    NASA Astrophysics Data System (ADS)

    Jin, Jae Sik

    2017-03-01

    Phonon dynamics in nanostructures is critically important to thermoelectric and optoelectronic devices because it determines the transport and other crucial properties. However, accurately evaluating the phonon lifetimes is extremely difficult. This study reports on the development of a new semi-empirical method to estimate the full-spectrum phonon lifetimes in thin silicon films at room temperature based on the experimental data on the phonon mean-free-path spectrum in bulk silicon and a phenomenological consideration of phonon transport in thin films. The bulk of this work describes the theory and the validation; then, we discuss the trend of the phonon lifetimes in thin silicon films when their thicknesses decrease.

  20. Development of Highly Sensitive Bulk Acoustic Wave Device Biosensor Arrays for Screening and Early Detection of Prostate Cancer

    DTIC Science & Technology

    2009-01-01

    Acoustic Wave Device Biosensor Arrays for Screening and Early Detection of Prostate Cancer PRINCIPAL INVESTIGATOR: Anthony J. Dickherber, Ph.D...Arrays for Screening and Early Detection of Prostate Cancer 5b. GRANT NUMBER W81XWH-07-1-0099 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d...of developing a cost-effective, highly sensitive and highly selective sensor array for the detection of early cancer proliferation. First I report

  1. Microfluidic pumps employing surface acoustic waves generated in ZnO thin films

    SciTech Connect

    Du, X. Y.; Flewitt, A. J.; Milne, W. I.; Fu, Y. Q.; Luo, J. K.

    2009-01-15

    ZnO thin film based surface acoustic wave (SAW) devices have been utilized to fabricate microfluidic pumps. The SAW devices were fabricated on nanocrystalline ZnO piezoelectric thin films deposited on Si substrates using rf magnetron sputtering and use a Sezawa wave mode for effective droplet motion. The as-deposited ZnO surface is hydrophilic, with a water contact angle of {approx}75 deg., which prevents droplet pumping. Therefore, the ZnO surface was coated using a self-assembled monolayer of octadecyltrichlorosilane which forms a hydrophobic surface with a water contact angle of {approx}110 deg. Liquid droplets between 0.5 and 1 {mu}l in volume were successfully pumped on the hydrophobic ZnO surface at velocities up to 1 cm s{sup -1}. Under acoustic pressure, the water droplet on an hydrophilic surface becomes deformed, and the asymmetry in the contact angle at the trailing and leading edges allow the force acting upon the droplet to be calculated. These forces, which increase with input voltage above a threshold level, are found to be in the range of {approx}100 {mu}N. A pulsed rf signal has also been used to demonstrate precision manipulation of the liquid droplets. Furthermore, a SAW device structure is demonstrated in which the ZnO piezoelectric only exists under the input and output transducers. This structure still permits pumping, while avoiding direct contact between the piezoelectric material and the fluid. This is of particular importance for biological laboratory-on-a-chip applications.

  2. Surface acoustic wave technique for the characterization of porous properties of microporous silicate thin films

    NASA Astrophysics Data System (ADS)

    Hietala, Susan Leslie

    1997-12-01

    Features of gas adsorption onto sol-gel derived microporous silicate thin films, for characterization of porous properties, are detailed using a surface acoustic wave (SAW) technique. Mass uptake and film effective modulus changes calculated from the SAW data are investigated in detail. The effects of stress and surface tension on the SAW sensor are calculated and found to be negligible in these experiments. Transient behavior recorded during nitrogen adsorption at 77 K is discussed in the context of mass uptake and effective modulus contributions. The time constant associated with the effective modulus calculation is consistent with that of diffusivity of nitrogen into a 5A zeolite. Further calculations indicate that the transient behavior is not due to thermal effects. A unique dual sensor SAW experiment to decouple the mass and effective modulus contributions to the frequency response was performed in conjunction with a Silicon beam-bending experiment. The beam-bending experiment results in a calculation of stress induced during adsorption of methanol on a microporous silicate thin film. The decoupled mass and effective modulus calculated from the SAW data have similar shaped isotherms, and are quite different from that of the stress developed in the Silicon beam. The total effective modulus change calculated from the SAW data is consistent with that calculated using Gassmann's equation. The SAW system developed for this work included unique electronics and customized hardware which is suitable for work under vacuum and at temperatures from 77K to 473K. This unique setup is suitable for running thin film samples on a Micromeritics ASAP 2000 Gas Adsorption unit in automatic mode. This setup is also general enough to be compatible with a custom gas adsorption unit and the beam bending apparatus, both using standard vacuum assemblies.

  3. Two-band superconductivity of bulk and surface states in Ag thin films on Nb

    NASA Astrophysics Data System (ADS)

    Tomanic, Tihomir; Schackert, Michael; Wulfhekel, Wulf; Sürgers, Christoph; Löhneysen, Hilbert v.

    2016-12-01

    We use epitaxial strain to spatially tune the bottom of the surface-state band ESS of Ag(111) islands on Nb(110). Bulk and surface-state contributions to the Ag(111) local density of states (LDOS) can be separated with scanning tunneling spectroscopy. For thick islands (≈20 nm), the Ag surface states are decoupled from the Ag bulk states and the superconductive gap induced by proximity to Nb is due to bulk states only. However, for thin islands (3-4 nm), surface-state electrons develop superconducting correlations as identified by a complete energy gap in the LDOS when ESS is smaller than but close to the Fermi level. The induced superconductivity in this case is of a two-band nature and appears to occur when the surface-state wave function reaches down to the Ag/Nb interface.

  4. Advanced Nanoscale Thin Film & Bulk Materials Towards Thermoelectric Power Conversion Efficiencies of 30%

    DTIC Science & Technology

    2014-02-27

    APS, November 12-14, 2009, abstract #G2.007 4) R. Venkatasubramanian, G. Bulman, P. Barletta, J. Stuart & T. Colpitts, Thin-film 2-di superlattices...Presentation), JHU/APL WALEX Advanced Portable Power Systems Workshop, Johns Hopkins University, Laurel, MD, June 24, 2010 6) R. Venkatasubramanian, G...Bulman, P. Barletta, J. Stuart & T. Colpitts, High Figure of Merit Thin-film Superlattice Thermoelectric Materials and Devices (Invited Presentation

  5. Difference in chemical reactions in bulk plasma and sheath regions during surface modification of graphene oxide film using capacitively coupled NH{sub 3} plasma

    SciTech Connect

    Lee, Sung-Youp; Kim, Chan; Kim, Hong Tak

    2015-09-14

    Reduced graphene oxide (r-GO) films were obtained from capacitively coupled NH{sub 3} plasma treatment of spin-coated graphene oxide (GO) films at room temperature. Variations were evaluated according to the two plasma treatment regions: the bulk plasma region (R{sub bulk}) and the sheath region (R{sub sheath}). Reduction and nitridation of the GO films began as soon as the NH{sub 3} plasma was exposed to both regions. However, with the increase in treatment time, the reduction and nitridation reactions differed in each region. In the R{sub bulk}, NH{sub 3} plasma ions reacted chemically with oxygen functional groups on the GO films, which was highly effective for reduction and nitridation. While in the R{sub sheath}, physical reactions by ion bombardment were dominant because plasma ions were accelerated by the strong electrical field. The accelerated plasma ions reacted not only with the oxygen functional groups but also with the broken carbon chains, which caused the removal of the GO films by the formation of hydrocarbon gas species. These results showed that reduction and nitridation in the R{sub bulk} using capacitively coupled NH{sub 3} plasma were very effective for modifying the properties of r-GO films for application as transparent conductive films.

  6. Characterization of a 61-element bulk-PZT thick film deformable mirror and generation of Zernike polynomials

    NASA Astrophysics Data System (ADS)

    Ma, Jianqiang; Li, Baoqing; Chu, Jiaru

    2010-10-01

    This paper describes the characteristics of a 61 element piezoelectric deformable mirror (DM) based on bulk-PZT thick film and the generation of Zernike polynomials. This device consists of a continue silicon mirror supported by 61 element piezoelectric unimorph actuators which are arranged in a hexagonal grid with spacing of 5mm. Measurements of the displacement using a laser Doppler vibrometer demonstrated that the stroke of DM was 3.8μm at 100 volt with a displacement hysteresis of approximately 9% and the operating bandwidth was greater than 10KHz. A custom phasing-shifting interferometer based on Twyman-Green interferometer was developed to measure the mirror surface shape in response to the applied voltage. The influence function of the mirror measured accorded with Gaussian function with inter-actuator coupling of approximately 5%, which was similar to the traditional piezoelectric DM with stacked actuators. To examine the ability of the mirror to replicate optical aberrations described by the Zernike polynomials, low-order Zernike modes were reproduced by calculating the voltage on each actuator using an influence function matrix. The measurement demonstrated that the deformable mirror could produce the Zernike modes up to the ninth term. Considering the low-voltage actuation as well as the capability for miniaturization of the actuator size, deformable mirror actuated by bulk-PZT thick film has a potential application for low-cost adaptive optics.

  7. Electrochemical properties of the passive film on bulk Zr-Fe-Cr intermetallic fabricated by spark plasma sintering

    NASA Astrophysics Data System (ADS)

    Bai, Yakui; Ling, Yunhan; Lai, Wensheng; Xing, Shupei; Ma, Wen

    2016-12-01

    Although Zr-based second phase particles (SPPs) are important factors influencing corrosion resistance of zircaloy cladding materials, the corrosion behavior of SPPs has not been investigated by means of electrochemical method so far. In order to clarify the role of SPPs commonly existed in zircaloy, bulk Zr-based intermetallics were firstly fabricated by spark plasma sintering (SPS) at temperatures 1373 K and an applied pressure of 60 MPa in this work. Both the natural passive film on surface and oxidation behavior of intermetallic has been investigated in this work. X-ray diffraction (XRD) pattern showed that as-prepared intermetallic of crystal structure belongs to Laves phase with AB2 type. Electrochemical measurement of passive film on surface of bulk Zr-based intermetallic exhibited significant difference with that of zirconium. Potentiodynamic measurements results revealed that intermetallic exhibited higher corrosion potential and lower corrosion current density than that of pure zirconium, implying that Zr-based second phase will act as cathode when they are included in zirconium matrix. Meanwhile, significant improvement of Zr-Fe-Cr intermetallic on the water chemistry corrosion resistance was demonstrated comparing with Zr-Fe and Zr-Cr binary intermetallics.

  8. Ferroelectric Tungsten Bronze Bulk Crystals and Epitaxial Thin Films for Electro-Optic Device Applications

    DTIC Science & Technology

    1984-02-01

    110) film orientations. Electro - optic measurements on SBN:60 single crystals have shown a high value for r51 of 80 x 10 to the minus 12th power m/v...showing morphotropic boundary conditions with enhanced dielectric properties. Both systems look promising for future electro - optic development.

  9. Surface and related bulk properties of titania nanoparticles recovered from aramid–titania hybrid films: A novel attempt

    SciTech Connect

    Al-Omani, Sara J.; Bumajdad, Ali; Al Sagheer, Fakhreia A.; Zaki, Mohamed I.

    2012-11-15

    Highlights: ► Aramid–titania hybrid films (5 and 10 wt%-TiO{sub 2}) were prepared via sol–gel processing. ► 450 °C calcination of the films yield anatase-TiO{sub 2} nanoparticles of rod-like morphology. ► The titania nanoparticle, crystal structure, high surface area are stable up to 800 °C. ► The novel approach has the advantage of nearly 100% recovery of titania. ► Increasing calcination temperature up to 1100 °C triggers anatase → rutile transition. -- Abstract: 5 and 10 wt%-TiO{sub 2}-containing aramid–titania hybrid films were prepared using sol–gel processing improved by the inclusion of 3-isocyanato-propyltriethoxysilane (ICTOS) to strengthen bonding of the titania species to the polymer backbone and, hence, lessen its agglomeration. The films were thermally degraded by heating at 450 °C in a dynamic atmosphere of air. The solid residues were found by thermogravimetry, X-ray diffractometry and electron microscopy to consist dominantly of uniformly agglomerated rod-like anatase-TiO{sub 2} nanoparticles, irrespective of the titania content of the film. The recovered titania particle morphology and surface microstructure were examined by field emission scanning and high-resolution transmission electron microscopy, respectively. Whereas, the particle surface chemistry and texture were assessed, respectively, by means of X-ray photoelectron spectroscopy and N{sub 2} sorptiometry. The recovered titanias were found, irrespective of the film content of titania, to enjoy not only a high temperature (up to 800 °C) stable nanoscopic anatase bulk structure, but also a high-temperature stable surface chemical composition (lattice Ti{sup 4+} and O{sup 2−}, and adsorbed OH/CH{sub x} species), (101)-faceted microstructure and highly accessible (145–112 m{sup 2}/g), uniform mesoporous texture with average pore diameter in the narrow range of 3.9–6.3 nm. Increasing the calcination temperature up to 1100 °C enhances an anatase → rutile

  10. Polarity-inverted ScAlN film growth by ion beam irradiation and application to overtone acoustic wave (000-1)/(0001) film resonators

    SciTech Connect

    Suzuki, Masashi; Yanagitani, Takahiko; Odagawa, Hiroyuki

    2014-04-28

    Polarity inversion in wurtzite film is generally achieved by the epitaxial growth on a specific under-layer. We demonstrate polarity inversion of c-axis oriented ScAlN films by substrate ion beam irradiation without using buffer layer. Substrate ion beam irradiation was induced by either sputtering a small amount of oxide (as a negative ion source) onto the cathode or by applying a RF bias to the substrate. Polarity of the films was determined by a press test and nonlinear dielectric measurement. Second overtone thickness extensional mode acoustic resonance and suppression of fundamental mode resonance, indicating complete polarity inversion, were clearly observed in bilayer highly oriented (000-1)/(0001) ScAlN film.

  11. ZnO films on /001/-cut (110)-propagating GaAs substrates for surface acoustic wave device applications

    NASA Technical Reports Server (NTRS)

    Hickernell, Frederick S.; Higgins, Robert J.; Jen, Cheng-Kuei; Kim, Yoonkee; Hunt, William D.

    1995-01-01

    A potential application for piezoelectric films substrates is the monolithic integration of surface acoustic wave (SAW) devices with GaAs electronics. Knowledge of the SAW properties of the layered structure is critical for the optimum and accurate design of such devices. The acoustic properties of ZnO films sputtered on /001/-cut group of (110) zone axes-propagating GaAs substrates are investigated in this article, including SAW velocity, effective piezoelectric coupling constant, propagation loss, diffraction, velocity surface, and reflectivity of shorted and open metallic gratings. The measurements of these essential SAW properties for the frequency range between 180 and 360 MHz have been performed using a knife-edge laser probe for film thicknesses over the range of 1.6-4 micron and with films of different grain sizes. The high quality of dc triode sputtered films was observed as evidenced by high K(sup 2) and low attenuation. The measurements of the velocity surface, which directly affects the SAW diffraction, on the bare and metalized ZnO on SiO2 or Si3N4 on /001/-cut GaAs samples are reported using two different techniques: (1) knife-edge laser probe, (2) line-focus-beam scanning acoustic microscope. It was found that near the group of (110) zone axes propagation direction, the focusing SAW property of the bare GaAs changes into a nonfocusing one for the layered structure, but a reversed phenomenon exists near the (100) direction. Furthermore, to some extent the diffraction of the substrate can be controlled with the film thickness. The reflectivity of shorted and open gratings are also analyzed and measured. Zero reflectivity is observed for a shorted grating. There is good agreement between the measured data and theoretical values.

  12. ZnO Films on {001}-Cut <110>-Propagating GaAs Substrates for Surface Acoustic Wave Device Applications

    NASA Technical Reports Server (NTRS)

    Kim, Yoonkee; Hunt, William D.; Hickernell, Frederick S.; Higgins, Robert J.; Jen, Cheng-Kuei

    1995-01-01

    A potential application for piezoelectric films on GaAs substrates is the monolithic integration of surface acoustic wave (SAW) devices with GaAs electronics. Knowledge of the SAW properties of the layered structure is critical for the optimum and accurate design of such devices. The acoustic properties of ZnO films sputtered on {001}-cut <110> -propagating GaAs substrates are investigated in this article, including SAW Velocity effective piezoelectric coupling constant, propagation loss. diffraction, velocity surface, and reflectivity of shorted and open metallic gratings. The measurements of these essential SAW properties for the frequency range between 180 and 360 MHz have been performed using a knife-edge laser probe for film thicknesses over the range of 1.6-4 micron and with films or different grain sizes. The high quality of dc triode sputtered films was observed as evidenced by high K(exp 2) and low attenuation. The measurements of the velocity surface, which directly affects the SAW diffraction, on the bare and metalized ZnO on SiO2, or Si3N4 on {001}-cut GaAs samples are reported using two different techniques: 1) knife-edge laser probe, 2) line-focus-beam scanning acoustic microscope. It was found that near the <110> propagation direction, the focusing SAW property of the bare GaAs changes into a nonfocusing one for the layered structure, but a reversed phenomenon exists near the <100> direction. Furthermore, to some extent the diffraction of the substrate can be controlled with the film thickness. The reflectivity of shorted and open gratings are also analyzed and measured. Zero reflectivity is observed for a shorted grating. There is good agreement between the measured data and theoretical values.

  13. Fabrication and Characterization of PZT Thin-Film on Bulk Micromachined Si Motion Detectors

    SciTech Connect

    Clem, P.; Garino, T.J.; Laguna, G.; Tuttle, B.A.

    1999-01-07

    Motion detectors consisting of Pb(Zr{sub x}Ti{sub (1{minus}x)})O{sub 3} (PZT) thin films, between platinum electrodes, on micromachined silicon compound clamped-clamped or cantilever beam structures were fabricated using either hot KOH or High Aspect Ratio Silicon Etching (HARSE) to micromachine the silicon. The beams were designed such that a thicker region served as a test mass that produced stress at the top of the membrane springs that supported it when the object to which the detector was mounted moved. The PZT film devices were placed on these membranes to generate a charge or a voltage in response to the stress through the piezoelectric effect. Issues of integration of the PZT device fabrication process with the two etching processes are discussed. The effects of PZT composition and device geometry on the response of the detectors to motion is reported and discussed.

  14. Soft electronic structure modulation of surface (thin-film) and bulk (ceramics) morphologies of TiO2-host by Pb-implantation: XPS-and-DFT characterization

    NASA Astrophysics Data System (ADS)

    Zatsepin, D. A.; Boukhvalov, D. W.; Gavrilov, N. V.; Zatsepin, A. F.; Shur, V. Ya.; Esin, A. A.; Kim, S. S.; Kurmaev, E. Z.

    2017-04-01

    The results of combined experimental and theoretical study of substitutional and clustering effects in the structure of Pb-doped TiO2-hosts (bulk ceramics and thin-film morphologies) are presented. Pb-doping of the bulk and thin-film titanium dioxide was made with the help of pulsed ion-implantation without posterior tempering (Electronic Structure Modulation Mode). The X-ray photoelectron spectroscopy (XPS) qualification of core-levels and valence bands and Density-Functional Theory (DFT) calculations were employed in order to study the yielded electronic structure of Pb-ion modulated TiO2 host-matrices. The combined XPS-and-DFT analysis has agreed definitely with the scenario of the implantation stimulated appearance of PbO-like structures in the bulk morphology of TiO2:Pb, whereas in thin-film morphology the PbO2-like structure becomes dominating, essentially contributing weak O/Pb bonding (PbxOy defect clusters). The crucial role of the oxygen hollow-type vacancies for the process of Pb-impurity "insertion" into the structure of bulk TiO2 was pointed out employing DFT-based theoretical background. Both experiment and theory established clearly the final electronic structure re-arrangement of the bulk and thin-film morphologies of TiO2 because of the Pb-modulated deformation and shift of the initial Valence Base-Band Width about 1 eV up.

  15. Pr{sub 0.67}Ba{sub 0.33}MnO{sub 3} in Bulk and Thin Film Ceramic

    SciTech Connect

    Wong, J. K.; Lim, K. P.; Halim, S. A.; Chen, S. K.; Ng, S. W.; Gan, H. M. Albert

    2011-03-30

    Bulk polycrystalline of Pr{sub 0.67}Ba{sub 0.33}MnO{sub 3}(PBMO) ceramic prepared via solid-state reaction and converted into thin films on corning glass, fused silica and MgO (100) by pulsed laser deposition (PLD) technique. As compared to bulk PBMO, the unit cell in thin film PBMO experienced positive misfit due to lattice strain induced by substrate used resulting MnO{sub 6} to deform (change in Mn-O-Mn bond angle and Mn-O bond length). Bulk PBMO had large grains ({approx}1.5{mu}m) as compared to thin film which are nano-sized (<100 nm). Two metal-insulator transition temperatures, T{sub P}(156 K and 190 K) were observed in bulk due to core-shell effect as proposed by Zhang et al.. In summary, variation of electrical behaviour was observed between bulk and thin film samples which believed to be due to the difference of ordering in core (body) and grain surface.

  16. Effect of Doping on beta-Tricalcium Phosphate Bioresorbable Bulk Material and Thin Film Coatings

    NASA Astrophysics Data System (ADS)

    Abdalla, Suhaila

    Magnesium has emerged as a revolutionary biodegradable metal for use as an orthopedic material, it has several advantages over the current metallic materials in use, including eliminating the effects of stress shielding, improving biocompatibility and inhibiting degradation rates, thus removing the requirement of a second surgery for implant removal. Due to the rapid degradation of magnesium, it is necessary to control the corrosion rates of the materials to match the rates of bone healing. This dissertation reports on the effect of doping on the properties of beta-tricalcium phosphate (beta-TCP). It also reports on its application as a thin film coating on magnesium alloys for implant applications. Adding various dopants to beta-TCP significantly influences critical properties. In this study, discs were fabricated in two compositions: (i) undoped beta-TCP, (ii) beta-TCP doped with 1.0 wt % MgO, 0.5 wt % ZnO, and 1.0 wt % TiO2. Films were fabricated from these compositions using the pulsed laser deposition (PLD) technique. These coatings were then characterized for corrosive, hardness, and cytocompatibility. The XRD patterns of the coating confirm the amorphous nature of the films. The presence of the metal oxides in beta-TCP improved ceramic densification. The application of these doped coatings was also found to increase the hardness by 88 %, the modulus of elasticity by 66 %, and improve corrosion resistance of the magnesium alloy substrate; with a 2.4 % improvement in Ecorr and 95 % decrease in icorr. Cell viability was studied using an osteoblast precursor cell line MC3T3-E1 to assure that the biocompatibility of these ceramics was not altered due to the dopants. Long-term biodegradation studies were conducted by measuring weight change and surface microstructure as a function of time in simulated body fluid. The results suggest that these coatings could be used for bioresorbable implants with improved corrosion resistance and increased hardness.

  17. Spin-orbit torques in Ta/TbxCo100-x ferrimagnetic alloy films with bulk perpendicular magnetic anisotropy

    NASA Astrophysics Data System (ADS)

    Ueda, Kohei; Mann, Maxwell; Pai, Chi-Feng; Tan, Aik-Jun; Beach, Geoffrey S. D.

    2016-12-01

    We quantified the bulk perpendicular magnetic anisotropy (PMA) and spin-orbit torques (SOTs) in bilayer Ta/TbxCo100-x ferrimagnetic alloy films with varying Tb concentration. The coercivity increases dramatically with increasing TbxCo100-x thickness and is enhanced by the presence of a Ta underlayer. The Ta underlayer simultaneously serves as a source of SOT due to the spin Hall effect, which we show provides an efficient means to manipulate the magnetization in bulk PMA materials. It is further shown that the sign of the anomalous Hall voltage is different for rare-earth (RE) and transition-metal (TM) dominated alloy compositions, whereas the sign of the SOT effective field remains the same, suggesting that the former is related to the TM sublattice magnetization whereas the latter is related to the net magnetization. Our results suggest that Ta/TbxCo100-x is a potential candidate for spin-orbitronic device applications and give insight into spin transport and SOTs in rare-earth/transition-metal alloys.

  18. Anaerobic treatment of wastewater with high suspended solids from a bulk drug industry using fixed film reactor (AFFR).

    PubMed

    Gangagni Rao, A; Venkata Naidu, G; Krishna Prasad, K; Chandrasekhar Rao, N; Venkata Mohan, S; Jetty, Annapurna; Sarma, P N

    2005-01-01

    Studies were carried out on the treatment of wastewater from a bulk drug industry using an anaerobic fixed film reactor (AFFR) designed and fabricated in the laboratory. The chemical oxygen demand (COD) and total dissolved solids (TDS) of the wastewater were found to be very high with low biochemical oxygen demand (BOD) to COD ratio and high total suspended solid (TSS) concentration. Acclimatization of seed consortia and startup of the reactor was carried out by directly using the wastewater, which resulted in reducing the period of startup to 30 days. The reactor was studied at different organic loading rates (OLR) and it was found that the optimum OLR was 10 kg COD/m(3)/day. The wastewater under investigation, which had a considerable quantity of SS, was treated anaerobically without any pretreatment. COD and BOD of the reactor outlet wastewater were monitored and at steady state and optimum OLR 60-70% of COD and 80-90% of BOD were removed. The reactor was subjected to organic shock loads at two different OLR and the reaction could withstand the shocks and performance could be restored to normalcy at that OLR. The results obtained indicated that AFFR could be used efficiently for the treatment of wastewater from a bulk drug industry having high COD, TDS and TSS.

  19. Anaerobic treatment of wastewater with high suspended solids from a bulk drug industry using fixed film reactor (AFFR).

    PubMed

    Rao, A Gangagni; Naidu, G Venkata; Prasad, K Krishna; Rao, N Chandrasekhar; Mohan, S Venkata; Jetty, Annapurna; Sarma, P N

    2004-07-01

    Studies are carried out on the treatment of wastewater from a bulk drug industry using an anaerobic fixed film reactor (AFFR) designed and fabricated in the laboratory. The chemical oxygen demand (COD) and total dissolved solids (TDS) of the wastewater are found to be very high with low Biochemical oxygen demand (BOD) to COD ratio and high total suspended solid (TSS) concentration. Acclimatization of seed consortia and start up of the reactor is carried out by directly using the wastewater, which resulted in reducing the period of startup to 30 days. The reactor is studied at different organic loading rates (OLR) and it is found that the optimum OLR is 10 kg COD/m3/day. The wastewater under investigation, which is having considerable quantity of SS, is treated anaerobically without any pretreatment. The COD and BOD of the reactor outlet wastewater are monitored and reduction at steady state and optimum OLR is observed to be 60-70% of COD and 80-90% of BOD. The reactor is subjected to organic shock loads at two different OLR and it is observed that the reactor could withstand shocks and performance could be restored to normalcy at that OLR. The results obtained indicated that AFFR could be used efficiently for the treatment of wastewater from a bulk drug industry having high COD, TDS and TSS.

  20. Self Assembled Spin Coated and Bulk Films of a Novel Polydiacetylene as Second Order NLO Polymers

    DTIC Science & Technology

    1994-05-31

    NLO Polymers 6. AUTHOm(m) R&T Code: 4132016 W.H. Kim, B. Bihari, R. Moody, N. B. Kodali , J.Kumar,S.K. Dr. JoAnn MilUiken Tripathy. 7. PERFORMING...Polymers by W.H. Kim, B. Bihari, R. Moody, N. B. Kodali , J.Kumar,S.K. Tripathy. Submitted to Macromolecules University of Massachusetts Lowell Department...FILMS OF A NOVEL POLYDIACETYLENE AS SECOND ORDER NLO POLYMERS W. H. Kim, B. Bihari+, R. Moody+, N. B. Kodali , J. Kumar+, and S. K. Tripathy, University

  1. Excitonic resonances in thin films of WSe2: from monolayer to bulk material

    NASA Astrophysics Data System (ADS)

    Arora, Ashish; Koperski, Maciej; Nogajewski, Karol; Marcus, Jacques; Faugeras, Clément; Potemski, Marek

    2015-06-01

    We present optical spectroscopy (photoluminescence and reflectance) studies of thin layers of the transition metal dichalcogenide WSe2, with thickness ranging from mono- to tetra-layer and in the bulk limit. The investigated spectra show the evolution of excitonic resonances as a function of layer thickness, due to changes in the band structure and, importantly, due to modifications of the strength of Coulomb interactions as well. The observed temperature-activated energy shift and broadening of the fundamental direct exciton are well accounted for by standard formalisms used for conventional semiconductors. A large increase of the photoluminescence yield with temperature is observed in a WSe2 monolayer, indicating the existence of competing radiative channels. The observation of absorption-type resonances due to both neutral and charged excitons in the WSe2 monolayer is reported and the effect of the transfer of oscillator strength from charged to neutral excitons upon an increase of temperature is demonstrated.

  2. Interaction of atomic oxygen with thin film and bulk copper: An XPS, AES, XRD, and profilometer study

    NASA Technical Reports Server (NTRS)

    Raikar, Genesh N.; Gregory, John C.; Christl, Ligia C.; Peters, Palmer N.

    1992-01-01

    The University of Alabama in Huntsville (UAH) experiment A-0114 was designed primarily to study degradation of material surfaces due to low earth orbital (LEO) atmospheric oxygen. The experiment contained 128 one inch circular samples: metals, polymers, carbons, and semiconductors. Among metal samples, copper has shown some interesting new results. Two types of copper samples, a film sputter coated on fused silica and a bulk piece of OFHC copper, were characterized employing a variety of techniques such as X-ray and Auger electron spectroscopies, X-ray diffraction, and high resolution profilometry. Cu 2p core level spectra were used to characterize the presence of Cu2O and CuO in addition to Cu Auger LMM lines. These results are supported by our recent X-ray diffraction studies which clearly establish the presence of Cu oxides which we were unable to prove in our earlier work. Profilometry showed an increase in thickness of the film sample where exposed to 106.7 +/- 0.5 nm from an initial thickness of 74.2 +/- 1.1 nm. Further studies with SEM and ellipsometry are underway.

  3. Towards p × n transverse thermoelectrics: extreme anisotropic conduction in bulk doped semiconductor thin films via proton implantation

    NASA Astrophysics Data System (ADS)

    Tang, Yang; Koblmüller, G.; Riedl, H.; Grayson, M.

    2016-03-01

    Transverse thermoelectrics promise entirely new strategies for integrated cooling elements for optoelectronics. The recently introduced p × n-type transverse thermoelectric paradigm indicates that the most important step to engineering artificial transverse thermoelectrics is to create alternate p- and n-doped layers with orthogonally oriented anisotropic conductivity. This paper studies an approach to creating extreme anisotropic conductivity in bulk-doped semiconductor thin films via ion implantation. This approach defines an array of parallel conduction channels with photolithographic patterning of an SiO2 mask layer, followed by proton implantation. With a 10 μm channel width and 20 μm pitch, both n-type and p-type Al0.42 Ga0.58As thin films demonstrate a conductivity anisotropy ratio σ /σ⊥ > 104 at room temperature, while the longitudinal resistivity along the channel direction after implantation only increased by a factor of 3.3 ˜ 3.6. This approach can be readily adapted to other semiconductor materials for artificial p × n-type transverse thermoelectrics as other applications.

  4. Plasmon-exciton interaction and screening of exciton in ZnO-based thin film on bulk Pt as analyzed by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Darma, Yudi; Dimas Satrya, Christoforus; Marlina, Resti; Kurniawan, Robi; Herng, Tun Seng; Ding, Jun; Rusydi, Andrivo

    2017-01-01

    We study plasmon-exciton interaction in ZnO-based thin film on bulk Pt by using high resolution spectroscopic ellipsometry. ZnO films on quartz are used as reference. This study shows the strong electronic interactions between ZnO film and Pt by considering the significant suppression of exciton in ZnO film, in comparison to ZnO film on quartz. We found that plasmon in Pt are responsible to provide transferred electron for electronic blocking of exciton in ZnO film induce by spontaneous recombination from Pt. In the case of Cu doped ZnO film, we confirm screening effects on exciton and a localized interband transition for both systems (ZnO film on Pt and ZnO film on quartz). In Cu-doped ZnO film, electronic blocking of exciton by Pt plasmon is more pronounce rather than screening effect by interband transition. Our results show the importance of plasmon from substrate and doping to modify the optical properties of wide bandgap semiconductor.

  5. Local elastic modulus of RF sputtered HfO{sub 2} thin film by atomic force acoustic microscopy

    SciTech Connect

    Jena, S. Tokas, R. B. Sarkar, P. Thakur, S.; Sahoo, N. K.; Misal, J. S.; Rao, K. D.

    2014-04-24

    Atomic force acoustic microscopy (AFAM) is a useful nondestructive technique for measurement of local elastic modulus of materials at nano-scale spatial resolution by measuring the contact resonance spectra for higher order modes of the AFM cantilever. The elastic modulus of RF sputtered HfO{sub 2} thin film has been measured quantitatively, using reference approach in which measurements are performed on the test and reference samples. Using AFAM, the measured elastic modulus of the HfO{sub 2} thin film is 223±27 GPa, which is in agreement with the literature value of 220±40 GPa for atomic layer deposited HfO{sub 2} thin film using nanoindentation technique.

  6. Simultaneous measurement of thermal conductivity and heat capacity of bulk and thin film materials using frequency-dependent transient thermoreflectance method.

    PubMed

    Liu, Jun; Zhu, Jie; Tian, Miao; Gu, Xiaokun; Schmidt, Aaron; Yang, Ronggui

    2013-03-01

    The increasing interest in the extraordinary thermal properties of nanostructures has led to the development of various measurement techniques. Transient thermoreflectance method has emerged as a reliable measurement technique for thermal conductivity of thin films. In this method, the determination of thermal conductivity usually relies much on the accuracy of heat capacity input. For new nanoscale materials with unknown or less-understood thermal properties, it is either questionable to assume bulk heat capacity for nanostructures or difficult to obtain the bulk form of those materials for a conventional heat capacity measurement. In this paper, we describe a technique for simultaneous measurement of thermal conductivity κ and volumetric heat capacity C of both bulk and thin film materials using frequency-dependent time-domain thermoreflectance (TDTR) signals. The heat transfer model is analyzed first to find how different combinations of κ and C determine the frequency-dependent TDTR signals. Simultaneous measurement of thermal conductivity and volumetric heat capacity is then demonstrated with bulk Si and thin film SiO2 samples using frequency-dependent TDTR measurement. This method is further testified by measuring both thermal conductivity and volumetric heat capacity of novel hybrid organic-inorganic thin films fabricated using the atomic∕molecular layer deposition. Simultaneous measurement of thermal conductivity and heat capacity can significantly shorten the development∕discovery cycle of novel materials.

  7. Growth and Characterization of Polyimide-Supported AlN Films for Flexible Surface Acoustic Wave Devices

    NASA Astrophysics Data System (ADS)

    Li, Qi; Liu, Hongyan; Li, Gen; Zeng, Fei; Pan, Feng; Luo, Jingting; Qian, Lirong

    2016-06-01

    Highly c-axis oriented aluminum nitride (AlN) films, which can be used in flexible surface acoustic wave (SAW) devices, were successfully deposited on polyimide (PI) substrates by direct current reactive magnetron sputtering without heating. The sputtering power, film thickness, and deposition pressure were optimized. The characterization studies show that at the optimized conditions, the deposited AlN films are composed of columnar grains, which penetrate through the entire film thickness (~2 μm) and exhibit an excellent (0002) texture with a full width at half maximum value of the rocking curve equal to 2.96°. The film surface is smooth with a root mean square value of roughness of 3.79 nm. SAW prototype devices with a center frequency of about 520 MHz and a phase velocity of Rayleigh wave of about 4160 m/s were successfully fabricated using the AlN/PI composite structure. The obtained results demonstrate that the highly c-axis oriented AlN films with a smooth surface and low stress can be produced on relatively rough, flexible substrates, and this composite structure can be possibly used in flexible SAW devices.

  8. Highly sensitive room-temperature surface acoustic wave (SAW) ammonia sensors based on Co₃O₄/SiO₂ composite films.

    PubMed

    Tang, Yong-Liang; Li, Zhi-Jie; Ma, Jin-Yi; Su, Hai-Qiao; Guo, Yuan-Jun; Wang, Lu; Du, Bo; Chen, Jia-Jun; Zhou, Weilie; Yu, Qing-Kai; Zu, Xiao-Tao

    2014-09-15

    Surface acoustic wave (SAW) sensors based on Co3O4/SiO2 composite sensing films for ammonia detection were investigated at room temperature. The Co3O4/SiO2 composite films were deposited onto ST-cut quartz SAW resonators by a sol-gel method. SEM and AFM characterizations showed that the films had porous structures. The existence of SiO2 was found to enhance the ammonia sensing property of the sensor significantly. The sensor based on a Co3O4/SiO2 composite film, with 50% Co3O4 loading, which had the highest RMS value (3.72), showed the best sensing property. It exhibited a positive frequency shift of 3500 Hz to 1 ppm ammonia as well as excellent selectivity, stability and reproducibility at room temperature. Moreover, a 37% decrease in the conductance of the composite film as well as a positive frequency shift of 12,500 Hz were observed when the sensor was exposed to 20 ppm ammonia, indicating the positive frequency shift was derived from the decrease in film conductance.

  9. Experimental study of ultra-thin films mechanical integrity by combined nanoindentation and nano-acoustic emission

    NASA Astrophysics Data System (ADS)

    Zhang, Zihou

    Advancement of interconnect technology has imposed significant challenge on interface characterization and reliability for blurred interfaces between layers. There is a need for material properties and these miniaturized length scales and assessment of reliability; including the intrinsic film fracture toughness and the interfacial fracture toughness. The nano-meter range of film thicknesses currently employed, impose significant challenges on evaluating these physical quantities and thereby impose significant challenge on the design cycle. In this study we attempted to use a combined nano-indentation and nano-acoustic emission to qualitatively and quantitatively characterize the failure modes in ultra-thin blanket films on Si substrates or stakes of different characteristics. We have performed and analyzed an exhaustive group of testes that cove many diverge combination of film-substrate combination, provided by both Intel and IBM. When the force-indentation depth curve shows excursion, a direct measure of the total energy release rate is estimated. The collected acoustic emission signal is then used to partition the total energy into two segments, one associated with the cohesive fracture toughness of the film and the other is for the adhesive fracture toughness of the interface. The acoustic emission signal is analyzed in both the time and frequency domain to achieve such energy division. In particular, the signal time domain analysis for signal skewness, time of arrival and total energy content are employed with the proper signal to noise ratio. In the frequency domain, an expansive group of acoustic emission signals are utilized to construct the details of the power spectral density. A bank of band-pass filters are designed to sort the individual signals to those associated with adhesive interlayer cracking, cohesive channel cracking, or other system induced noise. The attenuation time and the energy content within each spectral frequency were the key elements

  10. Determination of ammonium in Kjeldahl digests by gas-diffusion flow-injection analysis with a bulk acoustic wave-impedance sensor.

    PubMed

    Su, X L; Nie, L H; Yao, S Z

    1997-11-01

    A novel flow-injection analysis (FIA) system has been developed for the rapid and direct determination of ammonium in Kjeldahl digests. The method is based on diffusion of ammonia across a PTFE gas-permeable membrane from an alkaline (NaOH/EDTA) stream into a stream of diluted boric acid. The trapped ammonium in the acceptor is determined on line by a bulk acoustic wave (BAW)-impedance sensor and the signal is proportional to the ammonium concentration present in the digests. The proposed system exhibits a favorable frequency response to 5.0 x 10(-6)-4.0 x 10(-3) mol l(-1) ammonium with a detection limit of 1.0 x 10(-6) mol l(-1), and the precision was better than 1% (RSD) for 0.025-1.0 mM ammonium at a through-put of 45-50 samples h(-1). Results obtained for nitrogen determination in amino acids and for proteins determination in blood products are in good agreement with those obtained by the conventional distillation/titration method, respectively. The effects of composition of acceptor stream, cell constant of conductivity electrode, sample volume, flow rates and potential interferents on the FIA signals were discussed in detail.

  11. Mechanical back-action of a spin-wave resonance in a magnetoelastic thin film on a surface acoustic wave

    NASA Astrophysics Data System (ADS)

    Gowtham, P. G.; Labanowski, D.; Salahuddin, S.

    2016-07-01

    Surface acoustic waves (SAWs) traveling on the surface of a piezoelectric crystal can, through the magnetoelastic interaction, excite traveling spin-wave resonance in a magnetic film deposited on the substrate. This spin-wave resonance in the magnetic film creates a time-ynamic surface stress of magnetoelastic origin that acts back on the surface of the piezoelectric and modifies the SAW propagation. Unlike previous analyses that treat the excitation as a magnon-phonon polariton, here the magnetoelastic film is treated as a perturbation modifying boundary conditions on the SAW. We use acoustical perturbation theory to find closed-form expressions for the back-action surface stress and strain fields and the resultant SAW velocity shifts and attenuation. We demonstrate that the shear stres fields associated with this spin-wave back-action also generate effective surface currents on the piezoelectric both in phase and out of phase with the driving SAW potential. Characterization of these surface currents and their applications in determination of the magnetoelastic coupling are discussed. The perturbative calculation is carried out explicitly to first order (a regime corresponding to many experimental situations of current interest) and we provide a sketch of the implications of the theory at higher order.

  12. Free films of a partially wetting liquid under the influence of a propagating MHz surface acoustic wave

    NASA Astrophysics Data System (ADS)

    Altshuler, Gennady; Manor, Ofer

    2016-07-01

    We use both theory and experiment to study the response of thin and free films of a partially wetting liquid to a MHz vibration, propagating in the solid substrate in the form of a Rayleigh surface acoustic wave (SAW). We generalise the previous theory for the response of a thin fully wetting liquid film to a SAW by including the presence of a small but finite three phase contact angle between the liquid and the solid. The SAW in the solid invokes a convective drift of mass in the liquid and leaks sound waves. The dynamics of a film that is too thin to support the accumulation of the sound wave leakage is governed by a balance between the drift and capillary stress alone. We use theory to demonstrate that a partially wetting liquid film, supporting a weak capillary stress, will spread along the path of the SAW. A partially wetting film, supporting an appreciable capillary stress, will however undergo a concurrent dynamic wetting and dewetting at the front and the rear, respectively, such that the film will displace, rather than spread, along the path of the SAW. The result of the theory for a weak capillary stress is in agreement with the previous experimental and theoretical studies on the response of thin silicon oil films to a propagating SAW. No corresponding previous results exist for the case of an appreciable capillary stress. We thus complement the large capillary limit of our theory by undertaking an experimental procedure where we explore the response of films of water and a surfactant solutions to a MHz SAW, which is found to be in qualitative agreement with the theory at this limit.

  13. Impact of Resonant Infrared Matrix-Assisted Pulsed Laser Evaporation (RIR-MAPLE) on Morphology and Charge Conduction in Conjugated Polymer and Bulk Heterojunction Thin Films

    NASA Astrophysics Data System (ADS)

    Stiff-Roberts, Adrienne; McCormick, Ryan; Atewologun, Ayomide

    2014-03-01

    An approach to improve organic photovoltaic efficiency is to increase vertical charge conduction by promoting out-of-plane π- π stacking in conjugated polymers. Resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) features multiple growth parameters that can be varied to achieve a desired organic thin film property. In addition, RIR-MAPLE enables nanoscale domains in blended polymeric films and multi-layer polymeric films regardless of constituent solubility. Thus, RIR-MAPLE deposition is compared to solution-cast films as a possible approach to increase out-of-plane charge transport in polymers and bulk heterojunctions. Two common, solar cell polymers are investigated: P3HT and PCPDTBT. Materials characterization includes grazing-incidence, wide angle x-ray scattering (GIWAXS) for structural information and two techniques to determine hole mobility: organic field effect transistors to measure in-plane mobility and charge extraction by linearly increasing voltage to measure out-of-plane mobility. Initial indications are that the RIR-MAPLE films have a fundamentally different morphology compared to solution-cast films. In the case of P3HT, an enhancement in out-of-plane π- π stacking was observed by GIWAXS in RIR-MAPLE films compared to solution-cast films. A portion of this research was conducted at CNMS at ORNL.

  14. Surface acoustic wave properties of proton-exchanged LiNbO3 waveguides with SiO2 film.

    PubMed

    Kao, Kuo-Sheng; Cheng, Chien-Chuan; Chung, Chung-Jen; Chen, Ying-Chung

    2005-03-01

    Surface acoustic wave (SAW) properties of proton-exchanged (PE) z-cut lithium niobate (LiNbO3) waveguides with silicon dioxide (SiO2) film layers were investigated using octanoic acid. The distribution of hydrogen measured by secondary ion mass spectrometry (SIMS) showed a step-like profile, which was assumed to be equal to the waveguide depth (d). The SiO2 film was deposited on z-cut LiNbO3 waveguide by radio frequency (rf) magnetron sputtering. We investigated the important parameters for the design of SAW devices such as phase velocity (Vp), insertion loss (IL) and temperature coefficient of frequency (TCF) by a network analyzer using thin-film aluminum interdigital transducer electrodes on the upper SiO2 film surface. The experimental results showed that the Vp of SAW decreased slightly with the increase of h/lambda, where h was the thickness of SiO2 films and lambda was the wavelength. The IL of SAW increased with increased h/lambda. The TCF of SAW calculated from the frequency change of the output of SAW delay line showed an evident decrease with the increase of h/lambda. The TCF for PE z-cut LiNbO3 was measured to be about -54.72 ppm/degreees C at h/lambda = 0.08. It revealed that the SiO2 films could compensate and improve the temperature stability as compared with the TCF of SAW on PE samples without SiO2 film.

  15. A surface acoustic wave humidity sensor with high sensitivity based on electrospun MWCNT/Nafion nanofiber films

    NASA Astrophysics Data System (ADS)

    Sheng, Lei; Dajing, Chen; Yuquan, Chen

    2011-07-01

    Humidity detection has been widely used in a variety of fields. A humidity sensor with high sensitivity is reported in this paper. A surface acoustic wave resonator (SAWR) with high resonance frequency was fabricated as a basic sensitive component. Various nanotechnologies were used to improve the sensor's performance. A multi-walled carbon nanotube/Nafion (MWCNT/Nafion) composite material was prepared as humidity-sensitive films, deposited on the surface of an SAWR by the electrospinning method. The electrospun MWCNT/Nafion nanofiber films showed a three-dimensional (3D) porous structure, which was profitable for improving the sensor's performance. The new nano-water-channel model of Nafion was also applied in the humidity sensing process. Compared to other research, the present sensor showed excellent sensitivity (above 400 kHz/% relative humidity (RH) in the range from 10% RH to 80% RH), good linearity (R2 > 0.98) and a short response time (~3 s@63%).

  16. A high-overtone bulk acoustic wave resonator-oscillator-based 4.596 GHz frequency source: Application to a coherent population trapping Cs vapor cell atomic clock

    NASA Astrophysics Data System (ADS)

    Daugey, Thomas; Friedt, Jean-Michel; Martin, Gilles; Boudot, Rodolphe

    2015-11-01

    This article reports on the design and characterization of a high-overtone bulk acoustic wave resonator (HBAR)-oscillator-based 4.596 GHz frequency source. A 2.298 GHz signal, generated by an oscillator constructed around a thermally controlled two-port aluminum nitride-sapphire HBAR resonator with a Q-factor of 24 000 at 68 °C, is frequency multiplied by 2-4.596 GHz, half of the Cs atom clock frequency. The temperature coefficient of frequency of the HBAR is measured to be -23 ppm/ °C at 2.298 GHz. The measured phase noise of the 4.596 GHz source is -105 dB rad2/Hz at 1 kHz offset and -150 dB rad2/Hz at 100 kHz offset. The 4.596 GHz output signal is used as a local oscillator in a laboratory-prototype Cs microcell-based coherent population trapping atomic clock. The signal is stabilized onto the atomic transition frequency by tuning finely a voltage-controlled phase shifter implemented in the 2.298 GHz HBAR-oscillator loop, preventing the need for a high-power-consuming direct digital synthesis. The short-term fractional frequency stability of the free-running oscillator is 1.8 × 10-9 at one second integration time. In locked regime, the latter is improved in a preliminary proof-of-concept experiment at the level of 6.6 × 10-11 τ-1/2 up to a few seconds and found to be limited by the signal-to-noise ratio of the detected CPT resonance.

  17. A high-overtone bulk acoustic wave resonator-oscillator-based 4.596 GHz frequency source: Application to a coherent population trapping Cs vapor cell atomic clock

    SciTech Connect

    Daugey, Thomas; Friedt, Jean-Michel; Martin, Gilles; Boudot, Rodolphe

    2015-11-15

    This article reports on the design and characterization of a high-overtone bulk acoustic wave resonator (HBAR)-oscillator-based 4.596 GHz frequency source. A 2.298 GHz signal, generated by an oscillator constructed around a thermally controlled two-port aluminum nitride-sapphire HBAR resonator with a Q-factor of 24 000 at 68 °C, is frequency multiplied by 2–4.596 GHz, half of the Cs atom clock frequency. The temperature coefficient of frequency of the HBAR is measured to be −23 ppm/ °C at 2.298 GHz. The measured phase noise of the 4.596 GHz source is −105 dB rad{sup 2}/Hz at 1 kHz offset and −150 dB rad{sup 2}/Hz at 100 kHz offset. The 4.596 GHz output signal is used as a local oscillator in a laboratory-prototype Cs microcell-based coherent population trapping atomic clock. The signal is stabilized onto the atomic transition frequency by tuning finely a voltage-controlled phase shifter implemented in the 2.298 GHz HBAR-oscillator loop, preventing the need for a high-power-consuming direct digital synthesis. The short-term fractional frequency stability of the free-running oscillator is 1.8 × 10{sup −9} at one second integration time. In locked regime, the latter is improved in a preliminary proof-of-concept experiment at the level of 6.6 × 10{sup −11} τ{sup −1/2} up to a few seconds and found to be limited by the signal-to-noise ratio of the detected CPT resonance.

  18. High Performance Flexible Actuator of Urchin-Like ZnO Nanostructure/Polyvinylenefluoride Hybrid Thin Film with Graphene Electrodes for Acoustic Generator and Analyzer.

    PubMed

    Cheong, Oug Jae; Lee, James S; Kim, Jae Hyun; Jang, Jyongsik

    2016-05-01

    A bass frequency response enhanced flexible polyvinylidene fluoride (PVDF) based thin film acoustic actuator is successfully fabricated. High concentrations of various zinc oxide (ZnO) is embedded in PVDF matrix, enhancing the β phase content and the dielectric property of the composite thin film. ZnO acts as a nucleation agent for the crystallization of PVDF. A chemical vapor deposition grown graphene is used as electrodes, enabling high electron mobility for the distortion free acoustic signals. The frequency response of the fabricated acoustic actuator is studied as a function of the film thickness and filler content. The optimized film has a thickness of 80 μm with 30 wt% filler content and shows 72% and 42% frequency response enhancement in bass and midrange compared to the commercial PVDF, respectively. Also, the total harmonic distortion decreases to 82% and 74% in the bass and midrange regions, respectively. Furthermore, the composite film shows a promising potential for microphone applications. Most of all, it is demonstrated that acoustic actuator performance is strongly influenced by degree of PVDF crystalline.

  19. Theoretical analysis of surface acoustic wave propagating properties of Y-cut nano lithium niobate film on silicon dioxide

    SciTech Connect

    Chen, Jing Zhang, Qiaozhen; Han, Tao; Zhou, Liu; Tang, Gongbin; Liu, Boquan; Ji, Xiaojun

    2015-08-15

    The surface acoustic wave (SAW) propagating characteristics of Y-cut nano LiNbO{sub 3} (LN) film on SiO{sub 2}/LN substrate have been theoretically calculated. The simulated results showed a shear horizontal (SH) SAW with enhanced electromechanical coupling factor K{sup 2} owing to a dimensional effect of the nanoscale LN film. However, a Rayleigh SAW and two other resonances related to thickness vibrations caused spurious responses for wideband SAW devices. These spurious waves could be fully suppressed by properly controlling structural parameters including the electrode layer height, thickness, and the Euler angle (θ) of the LN thin film. Finally, a pure SH SAW was obtained with a wide θ range, from 0° to 5° and 165° to 180°. The largest K{sup 2} achieved for the pure SH SAW was about 35.1%. The calculated results demonstrate the promising application of nano LN film to the realization of ultra-wideband SAW devices.

  20. Giant Rashba Splitting in Pb1-x Snx Te (111) Topological Crystalline Insulator Films Controlled by Bi Doping in the Bulk.

    PubMed

    Volobuev, Valentine V; Mandal, Partha S; Galicka, Marta; Caha, Ondřej; Sánchez-Barriga, Jaime; Di Sante, Domenico; Varykhalov, Andrei; Khiar, Amir; Picozzi, Silvia; Bauer, Günther; Kacman, Perla; Buczko, Ryszard; Rader, Oliver; Springholz, Gunther

    2017-01-01

    The topological properties of lead-tin chalcogenide topological crystalline insulators can be widely tuned by temperature and composition. It is shown that bulk Bi doping of epitaxial Pb1-x Snx Te (111) films induces a giant Rashba splitting at the surface that can be tuned by the doping level. Tight binding calculations identify their origin as Fermi level pinning by trap states at the surface.

  1. Effect of an Eu{sup 3+} impurity on the antiferrodistortion and ferroelectric instabilities in an EuTiO{sub 3} bulk crystal and thin films

    SciTech Connect

    Zhandun, V. S. Zamkova, N. G.; Zinenko, V. I.

    2015-01-15

    The existence of an antiferrodistortion transition in EuTiO{sub 3} is disputable, and this question needs to be answered. One of the possible causes is the presence of an Eu{sup 3+} impurity in a sample. A nonempirical polarizable ion model is used to study the effect of a trivalent Eu{sup 3+} ion impurity on the antiferrodistortion and ferroelectric instabilities of an EuTiO{sub 3} crystal in the bulk and the thin-film states. Lattice dynamics calculation shows that a bulk impurity-free EuTiO{sub 3} crystal has no unstable modes throughout the entire phase space volume. The addition of an Eu{sup 3+} impurity leads to a significant softening of the rotational mode, the distortion in which makes tetragonal phase I4/mcm (which is experimentally observed) energetically favorable. In going from the bulk crystal to the thin film, the vibration spectrum of the impurity-free film has unstable antiferrodistortion and rotational modes. The addition of an Eu{sup 3+} impurity enhances the antiferrodistortion instability, which fully or partly suppresses ferroelectricity.

  2. Reorientation of the diagonal double-stripe spin structure at Fe1+yTe bulk and thin-film surfaces

    NASA Astrophysics Data System (ADS)

    Hänke, Torben; Singh, Udai Raj; Cornils, Lasse; Manna, Sujit; Kamlapure, Anand; Bremholm, Martin; Hedegaard, Ellen Marie Jensen; Iversen, Bo Brummerstedt; Hofmann, Philip; Hu, Jin; Mao, Zhiqiang; Wiebe, Jens; Wiesendanger, Roland

    2017-01-01

    Establishing the relation between ubiquitous antiferromagnetism in the parent compounds of unconventional superconductors and their superconducting phase is important for understanding the complex physics in these materials. Going from bulk systems to thin films additionally affects their phase diagram. For Fe1+yTe, the parent compound of Fe1+ySe1-xTex superconductors, bulk-sensitive neutron diffraction revealed an in-plane oriented diagonal double-stripe antiferromagnetic spin structure. Here we show by spin-resolved scanning tunnelling microscopy that the spin direction at the surfaces of bulk Fe1+yTe and thin films grown on the topological insulator Bi2Te3 is canted out of the high-symmetry directions of the surface unit cell resulting in a perpendicular spin component, keeping the diagonal double-stripe order. As the magnetism of the Fe d-orbitals is intertwined with the superconducting pairing in Fe-based materials, our results imply that the superconducting properties at the surface of the related superconducting compounds might be different from the bulk.

  3. First-principles study of the superconductivity in MgB2 bulk and in its bilayer thin film based on electron-phonon coupling

    NASA Astrophysics Data System (ADS)

    Morshedloo, T.; Roknabadi, M. R.; Behdani, M.

    2015-02-01

    In this paper, phonon-mediated superconductivity has been investigated in MgB2 bulk structure and bilayer thin film by using first-principles calculations. The electronic band structure, total and partial density of states (DOS and PDOS), phonon dispersion, isotropic Eliashberg function α2F(ω), and electron-phonon coupling have been calculated within the framework of density functional theory (DFT). Our results indicate that holes at the top of boron σ bands mainly and holes in the boron π band partially contribute to formation of coupled holes in superconductivity state. The density of states at the Fermi energy level is increased for MgB2 bilayer with respect to its bulk structure. According to the phonon dispersion and Eliashberg function curves, coupling considerably occurs between holes at the top of the boron σ band by means of optical phonon mode for both structures. This phonon mode has the E2g symmetry at the Г point. We obtain electron-phonon coupling constants of 0.74 and 0.91 for bulk and bilayer structures, respectively. By using the Allen-Dynes formula, we estimate superconducting transition temperature TC of 40 K for bulk and 48 K for the thin film.

  4. Reorientation of the diagonal double-stripe spin structure at Fe1+yTe bulk and thin-film surfaces

    PubMed Central

    Hänke, Torben; Singh, Udai Raj; Cornils, Lasse; Manna, Sujit; Kamlapure, Anand; Bremholm, Martin; Hedegaard, Ellen Marie Jensen; Iversen, Bo Brummerstedt; Hofmann, Philip; Hu, Jin; Mao, Zhiqiang; Wiebe, Jens; Wiesendanger, Roland

    2017-01-01

    Establishing the relation between ubiquitous antiferromagnetism in the parent compounds of unconventional superconductors and their superconducting phase is important for understanding the complex physics in these materials. Going from bulk systems to thin films additionally affects their phase diagram. For Fe1+yTe, the parent compound of Fe1+ySe1−xTex superconductors, bulk-sensitive neutron diffraction revealed an in-plane oriented diagonal double-stripe antiferromagnetic spin structure. Here we show by spin-resolved scanning tunnelling microscopy that the spin direction at the surfaces of bulk Fe1+yTe and thin films grown on the topological insulator Bi2Te3 is canted out of the high-symmetry directions of the surface unit cell resulting in a perpendicular spin component, keeping the diagonal double-stripe order. As the magnetism of the Fe d-orbitals is intertwined with the superconducting pairing in Fe-based materials, our results imply that the superconducting properties at the surface of the related superconducting compounds might be different from the bulk. PMID:28059102

  5. Reorientation of the diagonal double-stripe spin structure at Fe1+yTe bulk and thin-film surfaces

    DOE PAGES

    Hanke, Torben; Singh, Udai Raj; Cornils, Lasse; ...

    2017-01-06

    Here, establishing the relation between ubiquitous antiferromagnetism in the parent compounds of unconventional superconductors and their superconducting phase is important for understanding the complex physics in these materials. Going from bulk systems to thin films additionally affects their phase diagram. For Fe1+yTe, the parent compound of Fe1+ySe1$-x$Tex superconductors, bulk-sensitive neutron diffraction revealed an in-plane oriented diagonal double-stripe antiferromagnetic spin structure. Here we show by spin-resolved scanning tunnelling microscopy that the spin direction at the surfaces of bulk Fe1+yTe and thin films grown on the topological insulator Bi2Te3 is canted out of the high-symmetry directions of the surface unit cell resultingmore » in a perpendicular spin component, keeping the diagonal double-stripe order. As the magnetism of the Fe d-orbitals is intertwined with the superconducting pairing in Fe-based materials, our results imply that the superconducting properties at the surface of the related superconducting compounds might be different from the bulk.« less

  6. Structure-Processing Relationships in Solution Processable Polymer Thin Film Transistors and Small Molecule Bulk Heterojunction Solar Cells

    NASA Astrophysics Data System (ADS)

    Perez, Louis A.

    A regio-regular (RR) conjugated copolymer based on cyclopenta[2,1-b:3,4- b]dithiophene (CDT) and pyridal[2,1,3]thiadiazole (PT) structural units was prepared by using polymerization reactions involving reactants specifically designed to avoid random orientation of the asymmetric PT heterocycle. Compared to its regio-irregular (RI) counterpart, the RR polymer exhibits a two orders of magnitude increase in hole mobility from 0.005 to 0.6 cm2V -1s-1. To probe the reason for this difference in mobility, we examined the crystalline structure and its orientation in thin films of both copolymers as a function of depth via grazing incidence wide angle X-ray scattering (GIWAXS). In the RI film, the pi-pi stacking direction of the crystallites is mainly perpendicular to the substrate normal (edge-on orientation) while in the RR film the crystallites adopt a mixed pi-pi stacking orientation in the center of the film as well as near the interface between the polymer and the dielectric layer. These results demonstrate that control of backbone regularity is another important design criterion to consider in the synthesis and optimization of new conjugated copolymers with asymmetric structural units. Solution processed organic photovoltaic devices (OPVs) have emerged as a promising sustainable energy technology due to their ease of fabrication, potential to enable low-cost manufacturing, and ability to be incorporated onto light-weight flexible substrates. To date, the most efficacious OPV device architecture, the bulk heterojunction (BHJ), consists of a blend of a light-harvesting conjugated organic electron donating molecule and a strong electron-accepting compound (usually a soluble fullerene derivative e.g. [6,6]-phenyl C71 butyric acid methyl ester (PC71BM). BHJ layer morphology, which has been shown to be highly dependent on processing, has a significant effect on OPV performance. It is postulated that optimal BHJ morphologies consist of discrete bicontinuous nanoscale

  7. Fluorescence behavior of globular proteins from their bulk and thin film conformations in presence of mono-, di- and tri-valent ions.

    PubMed

    Bhowal, Ashim Chandra; Das, Kaushik; Kundu, Sarathi

    2015-09-01

    Photoluminescence behavior of globular proteins, lysozyme and bovine serum albumin (BSA), from their bulk and thin film conformations have been studied in presence of mono-, di- and tri-valent ions by using fluorescence and UV-Vis spectroscopy at two different temperatures and the morphology of the protein thin films have been studied by using atomic force microscopy. Protein- and ion-dependent dynamic and static quenching behaviors have been identified. While dynamic quenching is observed for lysozyme for all the three different valent ions, BSA shows no quenching for mono-valent (Na(+)) ions, dynamic quenching for di-valent (Ni(2+)) ions and static quenching for tri-valent (Fe(3+)) ions at pH≈5.5. After heat treatment, as the conformation of the protein molecules changes, the quenching efficiency for lysozyme in presence of ions decreases but shows enhancement for BSA. In thin film geometry, the molecular conformation of both lysozyme and BSA modifies on the solid surfaces and hence quenching efficiency also modifies in comparison with that of bulk and as a result the quenching efficiency for lysozyme increases but decreases for the BSA film.

  8. X-ray diffraction and surface acoustic wave analysis of BST/Pt/TiO2/SiO2/Si thin films

    NASA Astrophysics Data System (ADS)

    Mseddi, Souhir; Njeh, Anouar; Schneider, Dieter; Fuess, Hartmut; Hédi Ben Ghozlen, Mohamed

    2011-11-01

    High dielectric constant and electrostriction property of (Ba, Sr)Ti03 (BST) thin films result in an increasing interest for dielectric devices and microwave acoustic resonator. Barium strontium titanate (Ba0.645Sr0.355TiO3) films of about 300 nm thickness are grown on Pt(111)/TiO2/SiO2/Si(001) substrates by rf magnetron sputtering deposition techniques. X-ray diffraction is applied for the microstructural characterization. The BST films exhibit a cubic perovskite structure with a dense and smooth surface. A laser acoustic waves (LA-waves) technique is used to generate surface acoustic waves (SAW) propagating in the BST films. Young's modulus E and the Poisson ratio ν of TiO2, Pt and BST films in different propagation directions are derived from the measured dispersion curves. Estimation of BST elastics constants are served in SAW studies. Impact of stratification process on SAW, propagating along [100] and [110] directions of silicon substrate, has been interpreted on the basis of ordinary differential equation (ODE) and stiffness matrix method (SMM). A good agreement is observed between experimental and calculated dispersion curves. The performed calculations are strongly related to the implemented crystallographic data of each layer. Dispersion curves are found to be sensitive to the SAW propagation direction and the stratification process for the explored frequency ranges 50-250 MHz, even though it corresponds to a wave length clearly higher than the whole films thickness.

  9. The metal-insulator transition in vanadium dioxide: A view at bulk and surface contributions for thin films and the effect of annealing

    NASA Astrophysics Data System (ADS)

    Yin, W.; West, K. G.; Lu, J. W.; Pei, Y.; Wolf, S. A.; Reinke, P.; Sun, Y.

    2009-06-01

    Vanadium dioxide is investigated as potential oxide barrier in spin switches, and in order to incorporate VO2 layers in complex multilayer devices, it is necessary to understand the relation between bulk and surface/interface properties. Highly oriented VO2 thin films were grown on (0001) sapphire single crystal substrates with reactive bias target ion beam deposition. In the analysis of the VO2 films, bulk-sensitive methods [x-ray diffraction (XRD) and transport measurements] and surface sensitive techniques [photoelectron spectroscopy (PES) and scanning tunneling microscopy and spectroscopy] were employed. The samples were subjected to heating cycles with annealing temperatures of up to 425 and 525K. Prior to annealing the VO2 films exhibit the transition from the monoclinic to the tetragonal phase with the concurrent change in conductivity by more than a factor of 103 and their phase purity is confirmed by XRD. Annealing to 425K and thus cycling across the metal-insulator transition (MIT) temperature has no impact on the bulk properties of the VO2 film but the surface undergoes irreversible electronic changes. The observation of the valence band with PES during the annealing illustrates that the surface adopts a partially metallic character, which is retained after cooling. Annealing to a higher temperature (525K ) triggers a modification of the bulk, which is evidenced by a considerable reduction in the MIT characteristics, and a degradation in crystallite morphology. The local measurement of the conductivity with scanning tunneling spectroscopy shows the transition of the surface from predominantly semiconducting surface prior to annealing to a surface with an overwhelming contribution from metallic sections afterward. The spatial distribution of metallic regions cannot be linked in a unique manner to the crystallite size or location within the crystallites. The onset of oxygen depletion at the surface is held responsible for this behavior. The onset of bulk

  10. Ultra-violet absorption induced modifications in bulk and nanoscale electrical transport properties of Al-doped ZnO thin films

    NASA Astrophysics Data System (ADS)

    Kumar, Mohit; Basu, Tanmoy; Som, Tapobrata

    2015-08-01

    Using conductive atomic force microscopy and Kelvin probe force microscopy, we study local electrical transport properties in aluminum-doped zinc oxide (ZnO:Al or AZO) thin films. Current mapping shows a spatial variation in conductivity which corroborates well with the local mapping of donor concentration (˜1020 cm-3). In addition, a strong enhancement in the local current at grains is observed after exposing the film to ultra-violet (UV) light which is attributed to persistent photocurrent. Further, it is shown that UV absorption gives a smooth conduction in AZO film which in turn gives rise to an improvement in the bulk photoresponsivity of an n-AZO/p-Si heterojunction diode. This finding is in contrast to the belief that UV absorption in an AZO layer leads to an optical loss for the underneath absorbing layer of a heterojunction solar cell.

  11. Ultra-violet absorption induced modifications in bulk and nanoscale electrical transport properties of Al-doped ZnO thin films

    SciTech Connect

    Kumar, Mohit; Basu, Tanmoy; Som, Tapobrata

    2015-08-07

    Using conductive atomic force microscopy and Kelvin probe force microscopy, we study local electrical transport properties in aluminum-doped zinc oxide (ZnO:Al or AZO) thin films. Current mapping shows a spatial variation in conductivity which corroborates well with the local mapping of donor concentration (∼10{sup 20 }cm{sup −3}). In addition, a strong enhancement in the local current at grains is observed after exposing the film to ultra-violet (UV) light which is attributed to persistent photocurrent. Further, it is shown that UV absorption gives a smooth conduction in AZO film which in turn gives rise to an improvement in the bulk photoresponsivity of an n-AZO/p-Si heterojunction diode. This finding is in contrast to the belief that UV absorption in an AZO layer leads to an optical loss for the underneath absorbing layer of a heterojunction solar cell.

  12. Study on the interfacial adhesion property of low-k thin film by the surface acoustic waves with cohesive zone model

    NASA Astrophysics Data System (ADS)

    Xiao, Xia; Qi, Haiyang; Tao, Ye; Kikkawa, Takamaro

    2016-12-01

    The cohesive zone model being increasingly used in discrete fracture processes simulation is adopted to study the interfacial adhesion property of low dielectric constant film deposited on the silicon substrate in this work. The two parameters, maximum normal traction and normal interface characteristic length in cohesive zone model, are taken into account to calculate the theoretical surface acoustic wave dispersion curves. Broadband surface acoustic wave signals with effective frequency up to 200 MHz are generated by short pulse ultraviolet laser source and detected by a piezoelectric transducer. The interfacial adhesion properties of dense and porous films determined accurately by matching the experimental dispersion curves with the calculated theoretical dispersion curves are 10.7 PPa/m and 2.8 PPa/m, respectively. The results show that the adhesion quality of dense low dielectric constant film is better than that of the porous. The study exhibits that the adhesion properties determined by improved laser-generated surface acoustic wave technique have the same trends with the test results of the nanoscratch technique, which indicates that the surface acoustic wave technique with cohesive zone model is a promising and nondestructive method for determining interfacial adhesion properties between low dielectric constant film and substrate.

  13. In situ characterization of local elastic properties of thin shape memory films by surface acoustic waves

    NASA Astrophysics Data System (ADS)

    Grabec, Tomáš; Sedlák, Petr; Stoklasová, Pavla; Thomasová, Martina; Shilo, Doron; Kabla, Meni; Seiner, Hanuš; Landa, Michal

    2016-12-01

    The impulse stimulated thermal scattering experimental technique is used for contactless in situ detection of phase transitions in thin nickel-titanium films deposited on silicon substrates. It is shown that this technique enables the determination of the local properties of the film over a fully coated wafer, in particular the thickness of the film and the temperature dependence of the Young’s modulus, and can thus be used for monitoring of the spatial distribution of the functional properties in films prepared by a combinatorial sputtering approach.

  14. Phenomenological thermodynamic potentials for bulk and thin-film Ba (Zr0.08 Ti 0.92 ) O 3 single crystals

    NASA Astrophysics Data System (ADS)

    Peng, J. L.; Li, Q.; Shan, D. L.; Pan, K.; Yu, G. S.; Liu, Y. Y.

    2016-05-01

    Phenomenological thermodynamic analysis is an important theoretical investigation method for ferroelectric materials, however, it cannot be implemented for Ba ( Zr x Ti 1 - x ) O 3 due to the lack of thermodynamic potential coefficients. In this paper, we have constructed a phenomenological thermodynamic potential for bulk Ba ( Zr 0.08 Ti 0.92 ) O 3 single crystals, which reproduces the three phase transition temperatures, dielectric and piezoelectric constants of bulk Ba ( Zr 0.08 Ti 0.92 ) O 3 single crystals well, suggesting that the constructed thermodynamic potential is reliable. Then the thermodynamic potential with appropriate modification is applied to predict misfit strain-temperature phase diagram and electromechanical properties of Ba ( Zr 0.08 Ti 0.92 ) O 3 thin films. It is found that compressive strain favors the tetragonal c phase with an out-of-plane polarization component, while tensile misfit strain favors orthorhombic aa phase with an in-plane polarization component. It also reveals that Ba ( Zr 0.08 Ti 0.92 ) O 3 thin films under appropriate compressive strain show higher piezoelectric coefficient d15 than that of their bulk counterpart. The constructed thermodynamic potential opens a new avenue to theoretical analysis on Ba ( Zr 0.08 Ti 0.92 ) O 3 .

  15. An Integrated Laser-Induced Piezoelectric/Differential Confocal Surface Acoustic Wave System for Measurement of Thin Film Young's Modulus

    PubMed Central

    Yang, Fei; Dorantes-Gonzalez, Dante J.; Chen, Kun; Lu, Zimo; Jin, Baoyin; Li, Yanning; Chen, Zhi; Hu, Xiaotang

    2012-01-01

    The present paper presents the design and development results of a system setup for measuring Young's modulus of thin films by laser-induced surface acoustic waves based on the integration of two detection methods, namely, piezoelectric transducer detection and differential confocal detection, which may be used for conducting consecutive or simultaneous measurements. After demonstrating the capabilities of each detection approach, it is shown how, depending on a wider range of applications, sample materials and measurement environments, the developed integrated system inherits and harnesses the main characteristics of its detection channels, resulting in an more practical and flexible equipment for determining Young's modulus than traditional nanoindentation equipment, and also suitable for cross-validation purposes.

  16. Common electronic origin of superconductivity in (Li,Fe)OHFeSe bulk superconductor and single-layer FeSe/SrTiO3 films.

    PubMed

    Zhao, Lin; Liang, Aiji; Yuan, Dongna; Hu, Yong; Liu, Defa; Huang, Jianwei; He, Shaolong; Shen, Bing; Xu, Yu; Liu, Xu; Yu, Li; Liu, Guodong; Zhou, Huaxue; Huang, Yulong; Dong, Xiaoli; Zhou, Fang; Liu, Kai; Lu, Zhongyi; Zhao, Zhongxian; Chen, Chuangtian; Xu, Zuyan; Zhou, X J

    2016-02-08

    The mechanism of high-temperature superconductivity in the iron-based superconductors remains an outstanding issue in condensed matter physics. The electronic structure plays an essential role in dictating superconductivity. Recent revelation of distinct electronic structure and high-temperature superconductivity in the single-layer FeSe/SrTiO3 films provides key information on the role of Fermi surface topology and interface in inducing or enhancing superconductivity. Here we report high-resolution angle-resolved photoemission measurements on the electronic structure and superconducting gap of an FeSe-based superconductor, (Li0.84Fe0.16)OHFe0.98Se, with a Tc at 41 K. We find that this single-phase bulk superconductor shows remarkably similar electronic behaviours to that of the superconducting single-layer FeSe/SrTiO3 films in terms of Fermi surface topology, band structure and the gap symmetry. These observations provide new insights in understanding high-temperature superconductivity in the single-layer FeSe/SrTiO3 films and the mechanism of superconductivity in the bulk iron-based superconductors.

  17. Common electronic origin of superconductivity in (Li,Fe)OHFeSe bulk superconductor and single-layer FeSe/SrTiO3 films

    PubMed Central

    Zhao, Lin; Liang, Aiji; Yuan, Dongna; Hu, Yong; Liu, Defa; Huang, Jianwei; He, Shaolong; Shen, Bing; Xu, Yu; Liu, Xu; Yu, Li; Liu, Guodong; Zhou, Huaxue; Huang, Yulong; Dong, Xiaoli; Zhou, Fang; Liu, Kai; Lu, Zhongyi; Zhao, Zhongxian; Chen, Chuangtian; Xu, Zuyan; Zhou, X. J.

    2016-01-01

    The mechanism of high-temperature superconductivity in the iron-based superconductors remains an outstanding issue in condensed matter physics. The electronic structure plays an essential role in dictating superconductivity. Recent revelation of distinct electronic structure and high-temperature superconductivity in the single-layer FeSe/SrTiO3 films provides key information on the role of Fermi surface topology and interface in inducing or enhancing superconductivity. Here we report high-resolution angle-resolved photoemission measurements on the electronic structure and superconducting gap of an FeSe-based superconductor, (Li0.84Fe0.16)OHFe0.98Se, with a Tc at 41 K. We find that this single-phase bulk superconductor shows remarkably similar electronic behaviours to that of the superconducting single-layer FeSe/SrTiO3 films in terms of Fermi surface topology, band structure and the gap symmetry. These observations provide new insights in understanding high-temperature superconductivity in the single-layer FeSe/SrTiO3 films and the mechanism of superconductivity in the bulk iron-based superconductors. PMID:26853801

  18. Increase of interface and bulk density of states in amorphous-indium-gallium-zinc-oxide thin-film transistors with negative-bias-under-illumination-stress time

    NASA Astrophysics Data System (ADS)

    Gwang Um, Jae; Mativenga, Mallory; Migliorato, Piero; Jang, Jin

    2012-09-01

    The evolution with time of interface trap density and bulk density of states in amorphous-indium-gallium-zinc-oxide thin-film transistors (TFTs), for negative-bias-under-illumination-stress (NBIS), is traced. Based on the combined analysis of TFT current-voltage and capacitance-voltage characteristics, position of Fermi energy, flat band voltage, interface trap density, and gap state density per unit energy are investigated as function of NBIS time and applied gate voltage. These key parameters help to identify the degradation phenomena responsible for the negative threshold voltage shift caused by NBIS. In particular, the interface trap density becomes more positive; from 0.03 × 1011/cm2 to 0.65 × 1011/cm2, while the gap trap density per unit energy also increases after NBIS, supporting defect creation in the bulk and build-up of positive charge at the gate insulator/active-layer interface as the mechanism responsible for NBIS instability.

  19. A New Commercializable Route for the Preparation of Single-Source Precursors for Bulk, Thin-Film, and Nanocrystallite I-III-IV Semiconductors

    NASA Technical Reports Server (NTRS)

    Banger, Kulbinder K.; Jin, Michael H. C.; Harris, Jerry D.; Fanwick, Philip E.; Hepp, Aloysius F.

    2004-01-01

    We report a new simplified synthetic procedure for commercial manufacture of ternary single source precursors (SSP). This new synthetic process has been successfully implemented to fabricate known SSPs on bulk scale and the first liquid SSPs to the semiconductors CuInSe2 and AgIn(x)S(y). Single crystal X-ray determination reveals the first unsolvated ternary AgInS SSP. SSPs prepared via this new route have successfully been used in a spray assisted chemical vapor deposition (CVD) process to deposit polycrystalline thin films, and for preparing ternary nanocrystallites.

  20. Elastic characterization of Au thin films utilizing laser induced acoustic Rayleigh waves

    NASA Astrophysics Data System (ADS)

    Haim, A.; Bar-Ad, S.; Azoulay, A.

    2011-01-01

    Wide frequency-band Rayleigh waves (~100 MHz) were utilized to characterize the elastic constants of thin Au/Cr films deposited on glass substrates. The Rayleigh waves were excited utilizing laser induced thermoelastic mechanism and detected using a knife-edge technique apparatus. The dispersion of the signals in glass substrates coated with Au/Cr was measured and fitted to theory using a non-linear regression algorithm. From the fitting, the Au films Young modulus and the film thickness were extracted. The results were analyzed with regards to AFM scans performed on the samples and independent thickness measurement done by a dektak3 profiler. Results show a good agreement between the two measurements.

  1. Surface acoustic wave response to optical absorption by graphene composite film.

    PubMed

    Chivukula, Venkata S; Ciplys, Daumantas; Kim, Jin Ho; Rimeika, Romualdas; Xu, Jimmy M; Shur, Michael S

    2012-02-01

    Propagation of surface acoustic waves in YZ LiNbO3 overlaid with graphene flakes has been investigated and its optical response to illumination by 633-nm light from a He-Ne laser was studied. The heating of the sample surface caused by optical absorption by the graphene led to a downshift in the transmitted SAW phase caused by the wave velocity's dependence on temperature. The proposed simple model based on optothermal SAW phase modulation was found to be in good agreement with the experimental results.

  2. Intrinsic spin polarized electronic structure of CrO{sub 2} epitaxial film revealed by bulk-sensitive spin-resolved photoemission spectroscopy

    SciTech Connect

    Fujiwara, Hirokazu; Sunagawa, Masanori; Kittaka, Tomoko; Terashima, Kensei; Wakita, Takanori; Muraoka, Yuji; Yokoya, Takayoshi

    2015-05-18

    We have performed bulk-sensitive spin-resolved photoemission spectroscopy in order to clarify the intrinsic spin-resolved electronic states of half-metallic ferromagnet CrO{sub 2}. We used CrO{sub 2} epitaxial films on TiO{sub 2}(100), which shows a peak at 1 eV with a clear Fermi edge, consistent with the bulk-sensitive PES spectrum for CrO{sub 2}. In spin-resolved spectra at 40 K, while the Fermi edge was observed in the spin up (majority spin) state, no states at the Fermi level (E{sub F}) with an energy gap of 0.5 eV below E{sub F} were observed in the spin down (minority spin) state. At 300 K, the gap in the spin down state closes. These results are consistent with resistivity measurements and magnetic hysteresis curves of the fabricated CrO{sub 2} film, constituting spectroscopic evidence for the half-metallicity of CrO{sub 2} at low temperature and reducing the spin polarization at room temperature. We also discuss the electron correlation effects of Cr 3d.

  3. X-ray diffraction and surface acoustic wave analysis of BST/Pt/TiO{sub 2}/SiO{sub 2}/Si thin films

    SciTech Connect

    Mseddi, Souhir; Hedi Ben Ghozlen, Mohamed; Njeh, Anouar; Schneider, Dieter; Fuess, Hartmut

    2011-11-15

    High dielectric constant and electrostriction property of (Ba, Sr)Ti0{sub 3} (BST) thin films result in an increasing interest for dielectric devices and microwave acoustic resonator. Barium strontium titanate (Ba{sub 0.645}Sr{sub 0.355}TiO{sub 3}) films of about 300 nm thickness are grown on Pt(111)/TiO{sub 2}/SiO{sub 2}/Si(001) substrates by rf magnetron sputtering deposition techniques. X-ray diffraction is applied for the microstructural characterization. The BST films exhibit a cubic perovskite structure with a dense and smooth surface. A laser acoustic waves (LA-waves) technique is used to generate surface acoustic waves (SAW) propagating in the BST films. Young's modulus E and the Poisson ratio {nu} of TiO{sub 2,} Pt and BST films in different propagation directions are derived from the measured dispersion curves. Estimation of BST elastics constants are served in SAW studies. Impact of stratification process on SAW, propagating along [100] and [110] directions of silicon substrate, has been interpreted on the basis of ordinary differential equation (ODE) and stiffness matrix method (SMM). A good agreement is observed between experimental and calculated dispersion curves. The performed calculations are strongly related to the implemented crystallographic data of each layer. Dispersion curves are found to be sensitive to the SAW propagation direction and the stratification process for the explored frequency ranges 50-250 MHz, even though it corresponds to a wave length clearly higher than the whole films thickness.

  4. Pinning in high performance MgB2 thin films and bulks: Role of Mg-B-O nano-scale inhomogeneities

    NASA Astrophysics Data System (ADS)

    Prikhna, Tatiana; Shapovalov, Andrey; Eisterer, Michael; Shaternik, Vladimir; Goldacker, Wilfried; Weber, Harald W.; Moshchil, Viktor; Kozyrev, Artem; Sverdun, Vladimir; Boutko, Viktor; Grechnev, Gennadiy; Gusev, Alexandr; Kovylaev, Valeriy; Shaternik, Anton

    2017-02-01

    The comparison of nano-crystalline MgB2 oxygen-containing thin film (140 nm) and highly dense bulk materials showed that the critical current density, Jc, depends on the distribution of Mg-B-O nano-scale inhomogeneities. It has been shown that MgB2 bulks with high Jc in low (∼106 A/cm2 in 0-1 T at 10 K) and medium magnetic fields contain MgB0.6-0.8O0.8-0.9 nano-inclusions, where δTc or a combined δTc (dominant) / δl pinning mechanism prevails, while in bulk MgB2 with high Jc in high magnetic fields (Birr(18.5 K) = 15 T, Bc2(0 K) = 42.1 T) MgB1.2-2.7O1.8-2.5 nano-layers are present and δl pinning prevails. The structure of oxygen-containing films with high Jc in low and high magnetic fields (Jc (0 Т) = 1.8 × 107 А/сm2 and Jc (5 Т) = 2 × 106 А/сm2 at 10 К) contains very fine oxygen-enriched Mg-B-O inhomogeneities and δl pinning is realized. The results of DOS calculations in MgB2-xOx cells for x = 0, 0.125, 0.25, 0.5, 1 demonstrate that all compounds are conductors with metal-like behaviour. In the case of ordered oxygen substitution for boron the binding energy, Eb, does not increase sufficiently as compared with that for MgB2, while when oxygen atoms form zigzag chains the calculated Eb is even lower (Eb = -1.15712 Ry).

  5. Surface tension and disjoining pressure of free-standing smectic films above the bulk smectic-A-isotropic transition temperature

    NASA Astrophysics Data System (ADS)

    Zakharov, A. V.; Śliwa, Izabela

    2014-03-01

    We have carried out a numerical study of both the structural and thermodynamic properties of free-standing smectic films for the case of enhanced pair interaction in the bounding layers. Calculations, based upon the extended McMillan's mean-field theory with anisotropic forces, show that the layer-thinning transitions are characterized by abrupt drops to lower values, both for a disjoining pressure and a fluctuation-induced long-range interaction between the smectic film surfaces, and then continues to increase with a larger positive slope. Reasonable agreement between the theoretically predicted and the experimentally obtained data on the surface tension of the partially fluorinated 5-n-alkyl-2-(4-n-(perfluoroalkyl-metheleneoxy)phenyl) film has been obtained.

  6. Fabrication and Properties of Bulk and Thick Film YTTRIUM(1) BARIUM(2) COPPER(3) OXYGEN(7-DELTA) Superconductors

    NASA Astrophysics Data System (ADS)

    Bailey, Andrew

    Many of the applications envisaged for the new high critical temperature cuprate superconductors require the ability to produce high quality material in layers of 1-100mum thickness which can be used as prepared, or after patterning into discrete forms. Among the possible applications in the foreseeable future are EMI/EMC shielding, pcb interconnects, inductances, stripline, mixers and resonators. Consequently it is important to establish methods of 'thick film' manufacture which provide the versatility necessary for the wide range of uses. During the course of this research, a variety of processing methods have been studied in an attempt to optimize the important film parameters of density, adhesion, strength and good stable superconducting characteristics. Details will be given of substrate-layer interaction for the various substrates that were studied, which included alumina, sapphire, single crystal (100)MgO and yttria stabilised zirconia together with a number of methods of substrate passivation. To date, the most successful substrate for Y_1Ba_2Cu_3O_{7-delta } thick film production has been yttria stabilised zirconia. This thesis will discuss the results of investigations, using yttria stabilised zirconia substrates, which have identified satisfactory means of obtaining superconducting layers with T_{c} = 91.5K and J_{c~ }3000 Acm^{-2} in zero applied magnetic field. At the time of writing, this value of critical current density remains the highest reported value for Y_1Ba_2Cu _3O_{7-delta} thick films. These high quality thick films were then used in a study of conduction mechanisms and the results are interpreted in terms of flux pinning and thermodynamic fluctuation theory. These results highlighted the complex nature of the conduction process in these new ceramics, which is dominated by the weak-link intergranular contacts. Finally, details are given of Josephson characteristics that were observed in variable thickness microbridges patterned into the

  7. Correlation between propagation loss and silicon dioxide film properties for surface acoustic wave devices.

    PubMed

    Matsuda, Satoru; Miura, Michio; Matsuda, Takashi; Ueda, Masanori; Satoh, Yoshio; Hashimoto, Ken-Ya

    2013-05-01

    The correlation between the propagation loss and SiO2 film properties has been studied for temperature-compensated SAW devices using the SiO2/LiNbO3 structure. The SAW devices were prepared under different deposition temperatures for SiO2 film. Although they possessed excellent temperature coefficient of elasticity characteristics, devices prepared at lower temperature showed lower Q-factors. The SiO2 films were also deposited on a Si substrate under the same deposition conditions used for the SAW device preparation. Optical characterization was performed with Fourier transform infrared spectroscopy (FT-IR), spectrometer measurement, and Raman spectroscopy. IR absorbance spectra were almost same in the FT-IR measurement. However, optical attenuation in the UV region decreased with the deposition temperature in the spectrometer measurement. The optical attenuation is caused by the increase of the extinction coefficient in the SiO2 layer, and its optical wavelength dependence indicated that observed excess attenuation is caused by Rayleigh scattering. The Raman scattering also decreased with the deposition temperature in the Raman spectroscopy. The scattering is caused by the distortion of the SiO2 network. These results indicate that the Rayleigh scattering caused by the distortion of the SiO2 network is the main contributor to the excess SAW propagation loss in this case.

  8. Acoustic wave based MEMS devices for biosensing applications.

    PubMed

    Voiculescu, Ioana; Nordin, Anis Nurashikin

    2012-03-15

    This paper presents a review of acoustic-wave based MEMS devices that offer a promising technology platform for the development of sensitive, portable, real-time biosensors. MEMS fabrication of acoustic wave based biosensors enables device miniaturization, power consumption reduction and integration with electronic circuits. For biological applications, the biosensors are integrated in a microfluidic system and the sensing area is coated with a biospecific layer. When a bioanalyte interacts with the sensing layer, mass and viscosity variations of the biospecific layer can be detected by monitoring changes in the acoustic wave properties such as velocity, attenuation, resonant frequency and delay time. Few types of acoustic wave devices could be integrated in microfluidic systems without significant degradation of the quality factor. The acoustic wave based MEMS devices reported in the literature as biosensors and presented in this review are film bulk acoustic wave resonators (FBAR), surface acoustic waves (SAW) resonators and SAW delay lines. Different approaches to the realization of FBARs, SAW resonators and SAW delay lines for various biochemical applications are presented. Methods of integration of the acoustic wave MEMS devices in the microfluidic systems and functionalization strategies will be also discussed.

  9. Aluminum nitride thin film based acoustic wave sensors for biosensing applications

    NASA Astrophysics Data System (ADS)

    Xu, Jianzeng

    In recent years, SAW devices have drawn enormous interest from the analytical assay and sensing business, especially in the biosensing area where highly sensitive, cost efficient and miniaturized sensors are in urgent needs. This dissertation focuses on the development of AIN thin film based SAW devices suitable for biosensing applications. AIN thin films have been synthesized on different orientations of sapphire substrates by a plasma source molecular beam epitaxy system. Surface and structural characterization techniques have been applied to investigate the film quality and the results show that high quality c-plane AIN was epitaxially grown on both c-plane and a-plane sapphire substrates. Complete process flows have been developed for the fabrication of SAW delay line and resonator devices. Important electrical parameters such as the insertion loss, bandwidth, and impedance have been measured to assist the design optimization and derivation the phase velocity, electromechanical coupling coefficient, and temperature coefficient of frequency. On both c-plane and a-plane sapphire substrates, the SAW phase velocities (˜5700 m/s) and electromechanical coupling coefficients (˜0.3%) have been thoroughly mapped out with respect to the propagation direction and film thickness to wavelength ratio. The data are of practical importance for designing AIN-based SAW devices. A higher velocity (>6000 m/s) shear horizontal SAW mode has been discovered only at isolated propagating directions. This mode is especially suitable for aqueous biosensing due to its weak energy coupling to liquid. Much stronger response of the SH-SAW mode has been detected on the c-plane AIN on a-plane sapphire structure than on the c-plane AIN on c-plane sapphire structure, which could be attributed to large anisotropy in a-plane sapphire substrate. Linear frequency-temperature relationship has also been observed for both modes. We further quantify the mass sensitivity of the SAW and SH-SAW by

  10. High performance AlScN thin film based surface acoustic wave devices with large electromechanical coupling coefficient

    SciTech Connect

    Wang, Wenbo; He, Xingli; Ye, Zhi E-mail: jl2@bolton.ac.uk; Wang, Xiaozhi; Mayrhofer, Patrick M.; Gillinger, Manuel; Bittner, Achim; Schmid, Ulrich

    2014-09-29

    AlN and AlScN thin films with 27% scandium (Sc) were synthesized by DC magnetron sputtering deposition and used to fabricate surface acoustic wave (SAW) devices. Compared with AlN-based devices, the AlScN SAW devices exhibit much better transmission properties. Scandium doping results in electromechanical coupling coefficient, K{sup 2}, in the range of 2.0% ∼ 2.2% for a wide normalized thickness range, more than a 300% increase compared to that of AlN-based SAW devices, thus demonstrating the potential applications of AlScN in high frequency resonators, sensors, and high efficiency energy harvesting devices. The coupling coefficients of the present AlScN based SAW devices are much higher than that of the theoretical calculation based on some assumptions for AlScN piezoelectric material properties, implying there is a need for in-depth investigations on the material properties of AlScN.

  11. Influence of magnetic anisotropy on dynamic magnonic crystals created by surface acoustic waves in yttrium iron garnet films

    NASA Astrophysics Data System (ADS)

    Kryshtal, R. G.; Medved, A. V.

    2017-03-01

    Experimental results on the investigation of the influence of magnetic crystallographic anisotropy onto parameters of dynamic magnonic crystals arising at surface acoustic wave (SAW) propagation in yttrium iron garnet (YIG) films are presented. The main features of such an influence, as we have shown, are: 1) appearance of extra magnonic band gaps together with the normal magnonic band gap existing without anisotropy, 2) the absence of reflections of the incident surface magnetostatic wave at the frequency of these extra gaps, 3) the same depth for the extra gaps was achieved with a relatively small SAW power, almost by the order of magnitude less than in the case of normal magnonic gaps caused by SAW. A possible explanation of the features is given on the base of inelastic scattering of surface magnetostatic waves by SAW with the transformation of the reflected surface wave to the anisotropic direct volume magnetostatic wave existence of which is due to cubic crystallographic anisotropy in YIG. These results may be useful in designing new devices of information processing.

  12. Evaluation and criterion determination of the low-k thin film adhesion by the surface acoustic waves with cohesive zone model

    NASA Astrophysics Data System (ADS)

    Xiao, Xia; Qi, Haiyang; Sui, Xiaole; Kikkawa, Takamaro

    2017-03-01

    The cohesive zone model (CZM) is introduced in the surface acoustic wave (SAW) technique to characterize the interfacial adhesion property of the low-k thin film deposited on the Silicon substrate. The ratio of the two parameters in the CZM, the maximum normal traction and normal interface characteristic length, is derived to evaluate the interfacial adhesion properties quantitatively. In this study, the adhesion criterion to judge the adhesion property is newly proposed by the CZM-SAW technique. The criterion determination processes of two kinds of film, dense and porous Black Diamond with different film thicknesses, are presented in this paper. The interfacial adhesion properties of the dense and porous Black Diamond films with different thicknesses are evaluated by the CZM-SAW technique quantitatively and nondestructively. The quantitative adhesion properties are obtained by fitting the experimental dispersion curves with maximum frequency up to 220 MHz with the theoretical ones. Results of the nondestructive CZM-SAW technique and the destructive nanoscratch exhibit the same trend in adhesion properties, which means that the CZM-SAW technique is a promising method for determining the interfacial adhesion. Meanwhile, the adhesion properties of the detected samples are judged by the determined criterion. The test results show that different test film materials with different film thicknesses ranging from 300 nm to 1000 nm are in different adhered conditions. This paper exhibits the advantage of the CZM-SAW technique which can be a universal method to characterize the film adhesion.

  13. Acoustic biosensors

    PubMed Central

    Fogel, Ronen; Seshia, Ashwin A.

    2016-01-01

    Resonant and acoustic wave devices have been researched for several decades for application in the gravimetric sensing of a variety of biological and chemical analytes. These devices operate by coupling the measurand (e.g. analyte adsorption) as a modulation in the physical properties of the acoustic wave (e.g. resonant frequency, acoustic velocity, dissipation) that can then be correlated with the amount of adsorbed analyte. These devices can also be miniaturized with advantages in terms of cost, size and scalability, as well as potential additional features including integration with microfluidics and electronics, scaled sensitivities associated with smaller dimensions and higher operational frequencies, the ability to multiplex detection across arrays of hundreds of devices embedded in a single chip, increased throughput and the ability to interrogate a wider range of modes including within the same device. Additionally, device fabrication is often compatible with semiconductor volume batch manufacturing techniques enabling cost scalability and a high degree of precision and reproducibility in the manufacturing process. Integration with microfluidics handling also enables suitable sample pre-processing/separation/purification/amplification steps that could improve selectivity and the overall signal-to-noise ratio. Three device types are reviewed here: (i) bulk acoustic wave sensors, (ii) surface acoustic wave sensors, and (iii) micro/nano-electromechanical system (MEMS/NEMS) sensors. PMID:27365040

  14. Acoustic biosensors.

    PubMed

    Fogel, Ronen; Limson, Janice; Seshia, Ashwin A

    2016-06-30

    Resonant and acoustic wave devices have been researched for several decades for application in the gravimetric sensing of a variety of biological and chemical analytes. These devices operate by coupling the measurand (e.g. analyte adsorption) as a modulation in the physical properties of the acoustic wave (e.g. resonant frequency, acoustic velocity, dissipation) that can then be correlated with the amount of adsorbed analyte. These devices can also be miniaturized with advantages in terms of cost, size and scalability, as well as potential additional features including integration with microfluidics and electronics, scaled sensitivities associated with smaller dimensions and higher operational frequencies, the ability to multiplex detection across arrays of hundreds of devices embedded in a single chip, increased throughput and the ability to interrogate a wider range of modes including within the same device. Additionally, device fabrication is often compatible with semiconductor volume batch manufacturing techniques enabling cost scalability and a high degree of precision and reproducibility in the manufacturing process. Integration with microfluidics handling also enables suitable sample pre-processing/separation/purification/amplification steps that could improve selectivity and the overall signal-to-noise ratio. Three device types are reviewed here: (i) bulk acoustic wave sensors, (ii) surface acoustic wave sensors, and (iii) micro/nano-electromechanical system (MEMS/NEMS) sensors.

  15. Transient absorption spectroscopy studies on polythiophene-fullerene bulk heterojunction organic blend films sensitized with a low-bandgap polymer.

    PubMed

    Löslein, Heiko; Ameri, Tayebeh; Matt, Gebhard J; Koppe, Markus; Egelhaaf, Hans J; Troeger, Anna; Sgobba, Vito; Guldi, Dirk M; Brabec, Christoph J

    2013-07-12

    Recently, the concept of near-infrared sensitization is successfully employed to increase the light harvesting in large-bandgap polymer-based solar cells. To gain deeper insights into the operation mechanism of ternary organic solar cells, a comprehensive understanding of charge transfer-charge transport in ternary blends is a necessity. Herein, P3HT:PCPDTBT:PCBM ternary blend films are investigated by transient absorption spectroscopy. Hole transfer from PCPDTBT-positive polarons to P3HT in the P3HT:PCPDTBT:PCBM 0.9:0.1:1 blend film can be visualized. This process evolves within 140 ps and is discussed with respect to the proposed charge-generation mechanisms.

  16. Measurement of the refractive index dispersion of As{sub 2}Se{sub 3} bulk glass and thin films prior to and after laser irradiation and annealing using prism coupling in the near- and mid-infrared spectral range

    SciTech Connect

    Carlie, N.; Petit, L.; Musgraves, J. D.; Richardson, K.

    2011-05-15

    The prism coupling technique has been utilized to measure the refractive index in the near- and mid-IR spectral region of chalcogenide glasses in bulk and thin film form. A commercial system (Metricon model 2010) has been modified with additional laser sources, detectors, and a new GaP prism to allow the measurement of refractive index dispersion over the 1.5-10.6 {mu}m range. The instrumental error was found to be {+-}0.001 refractive index units across the entire wavelength region examined. Measurements on thermally evaporated AMTIR2 thin films confirmed that (i) the film deposition process provides thin films with reduced index compared to that of the bulk glass used as a target, (ii) annealing of the films increases the refractive index of the film to the level of the bulk glass used as a target to create it, and (iii) it is possible to locally increase the refractive index of the chalcogenide glass using laser exposure at 632.8 nm.

  17. Measurement of the refractive index dispersion of As2Se3 bulk glass and thin films prior to and after laser irradiation and annealing using prism coupling in the near- and mid-infrared spectral range

    SciTech Connect

    Carlie, Nathan; Anheier, Norman C.; Qiao, Hong; Bernacki, Bruce E.; Phillips, Mark C.; Petit, Laticia; Musgraves, Jonathan D.; Richardson, Kathleen

    2011-05-01

    The prism coupling technique has been utilized to measure the refractive index in the near- and mid-IR spectral region of chalcogenide glasses in bulk and thin film form. A commercial system (Metricon model 2010) has been modified with additional laser sources, detectors, and a new GaP prism to allow the measurement of refractive index dispersion over the 1.5–10.6 μm range. The instrumental error was found to be ±0.001 refractive index units across the entire wavelength region examined. Measurements on thermally evaporated AMTIR2 thin films confirmed that (i) the film deposition process provides thin films with reduced index compared to that of the bulk glass used as a target, (ii) annealing of the films increases the refractive index of the film to the level of the bulk glass used as a target to create it, and (iii) it is possible to locally increase the refractive index of the chalcogenide glass using laser exposure at 632.8 nm.

  18. Measurement of the refractive index dispersion of As2Se3 bulk glass and thin films prior to and after laser irradiation and annealing using prism coupling in the near- and mid-infrared spectral range

    NASA Astrophysics Data System (ADS)

    Carlie, N.; Anheier, N. C.; Qiao, H. A.; Bernacki, B.; Phillips, M. C.; Petit, L.; Musgraves, J. D.; Richardson, K.

    2011-05-01

    The prism coupling technique has been utilized to measure the refractive index in the near- and mid-IR spectral region of chalcogenide glasses in bulk and thin film form. A commercial system (Metricon model 2010) has been modified with additional laser sources, detectors, and a new GaP prism to allow the measurement of refractive index dispersion over the 1.5-10.6 μm range. The instrumental error was found to be ±0.001 refractive index units across the entire wavelength region examined. Measurements on thermally evaporated AMTIR2 thin films confirmed that (i) the film deposition process provides thin films with reduced index compared to that of the bulk glass used as a target, (ii) annealing of the films increases the refractive index of the film to the level of the bulk glass used as a target to create it, and (iii) it is possible to locally increase the refractive index of the chalcogenide glass using laser exposure at 632.8 nm.

  19. First-principles simulation of the optical response of bulk and thin-film α-quartz irradiated with an ultrashort intense laser pulse

    SciTech Connect

    Lee, Kyung-Min; Min Kim, Chul; Moon Jeong, Tae; Sato, Shunsuke A.; Otobe, Tomohito; Shinohara, Yasushi; Yabana, Kazuhiro

    2014-02-07

    A computational method based on a first-principles multiscale simulation has been used for calculating the optical response and the ablation threshold of an optical material irradiated with an ultrashort intense laser pulse. The method employs Maxwell's equations to describe laser pulse propagation and time-dependent density functional theory to describe the generation of conduction band electrons in an optical medium. Optical properties, such as reflectance and absorption, were investigated for laser intensities in the range 10{sup 10} W/cm{sup 2} to 2 × 10{sup 15} W/cm{sup 2} based on the theory of generation and spatial distribution of the conduction band electrons. The method was applied to investigate the changes in the optical reflectance of α-quartz bulk, half-wavelength thin-film, and quarter-wavelength thin-film and to estimate their ablation thresholds. Despite the adiabatic local density approximation used in calculating the exchange–correlation potential, the reflectance and the ablation threshold obtained from our method agree well with the previous theoretical and experimental results. The method can be applied to estimate the ablation thresholds for optical materials, in general. The ablation threshold data can be used to design ultra-broadband high-damage-threshold coating structures.

  20. The Vibration and Acoustic Properties of Pipes with Squeeze Film and Some Friction Damping Systems.

    NASA Astrophysics Data System (ADS)

    Li, Meng

    1991-01-01

    Available from UMI in association with The British Library. This study was motivated by the need to decrease the noise radiation and vibration of pipework in power plants, particularly at elevated temperature. A thin circular cylindrical shell has been studied theoretically. The exact solutions for natural frequencies of the symmetrical and anti-symmetrical modes for cylindrical shell vibration have been derived in matrix form. Using this theory, numerical results for natural frequencies and mode shapes with free-free, clamped-free and clamped -clamped boundary conditions have been evaluated. Based upon studies of the thin cylindrical shell theory and the physical phenomenon of air film damping of two parallel plates, the theory for predicting the loss factor of an annular double pipe damping system with a very small air gap has been developed. Flugge's thin shell equations of motion and the Navier-Stokes equation for viscous fluid were employed in the analysis. The fluid motion was expressed in terms of the shell displacement by using a travelling wave type solution. The solutions gave the fluid velocity profiles and stresses in the clearance between two cylindrical, concentric shells. According to the definition of energy dissipated in the fluid, an equation was derived for predicting the loss factor of the whole damping system. Based on the principle of similarity, an optimum design for a system generating squeeze film damping in pipes has been made. The theory was then extended to study the damping caused by various kinds of viscous fluid in the gap between the two annular structures. Experiments have been carried out to investigate the loss factor of the double pipe system with in-phase and out-of-phase modes of vibration. Friction damping has been studied experimentally on a thin-walled pipe with a coiled steel spring or wire rope attached or with a mineral wool wrapping. Flexural vibration was examined in the experiments. This study included an experimental

  1. Bulk heterojunction thin film formation by single and dual feed ultrasonic spray method for application in organic solar cells

    NASA Astrophysics Data System (ADS)

    Marathe, D. M.; Tarkas, H. S.; Mahajan, M. S.; Lonkar, G. S.; Tak, S. R.; Sali, J. V.

    2016-09-01

    We here present a way of preparing the polymer: fullerene BHJ using dual feed method which can lead to formation of pure phases. In this report, we present results of our initial experiments in this direction. The effect of process parameters on the thickness and surface roughness of the active layer has been discussed. The structural and optical properties have been studied using the optical microscope, UV—visible spectroscopy and photoluminescence spectroscopy. Significant PL quenching indicates efficient charge separation in the BHJ formed using this technique. We have also compared the BHJ thin films prepared with this dual feed ultrasonic technique with the single feed spray method. The BHJ formed using this technique has been used as an active layer in OSC. supported by the University Grants Commission, New Delhi, under Faculty Improvement Programme (No. 33-02/12(WRO) Dt.19.03.2013) and the Special Assistance Programme (530/2/DRS/2010(SAP-I)) Phase-II.

  2. Acoustic neuroma

    MedlinePlus

    Vestibular schwannoma; Tumor - acoustic; Cerebellopontine angle tumor; Angle tumor; Hearing loss - acoustic; Tinnitus - acoustic ... Acoustic neuromas have been linked with the genetic disorder neurofibromatosis type 2 (NF2). Acoustic neuromas are uncommon.

  3. Kinetics of electrochemically controlled surface reactions on bulk and thin film metals studied with Fourier transform impedance spectroscopy and surface plasmon resonance techniques

    NASA Astrophysics Data System (ADS)

    Assiongbon, Kankoe A.

    2005-07-01

    In the work presented in this thesis, the surface sensitive electrochemical techniques of cyclic voltametry (CV), potential step (PS) and Fourier transform impedance spectroscopy (FT-EIS), as well as the optical technique of surface plasmon resonance (SPR), were used to probe a wide variety of surface processes at various metal/liquid interface. Three polycrystalline metals (Au, Ta and Cu) and a Cr-coated gold film were used for these studies in different aqueous environments. A combination of CV with FT-EIS and PS was used to investigate electronic and structural proprieties of a modified bulk electrode of Au. This experimental system involved under potential deposition (UPD) of Bi3+ on Au in a supporting aqueous electrolyte containing ClO-4 . UPD range of Bi3+ was determined, and adsorption kinetics of Bi3+ in the presence of coadsorbing anion, ClO-4 were quantified. Potentiodynamic growth of oxide films of Ta in the following electrolytes NaNO3, NaNO3 + 5wt% H2O2, NaOH and NaOH + 5wt% H2O2 had been investigated. The oxide films were grown in the range -0.1 → +0.4V (high electric field) at a scan rate of 10 mV/s. Time resolved A.C. impedance spectroscopy measurements in the frequency range (0.1--20 KHz) were performed to characterize the surface reactions of oxide formation. The results are interpreted in terms of charge conductivity O2- through the oxide film, and disintegration of H2O2 into OH-. In a high pH medium (pH 12), dissociation of H2O2 was catalytically enhanced. This led to destabilization of the electrogenerated tantalum oxide surface film in the form of a soluble hexatantalate species. In contrast with the electrolytes, NaNO3, NaNO3 + 5wt% H2O2, NaOH, where only the oxide growth was observed, the A.C. impedance spectroscopy measurements in NaOH + 5wt% H 2O2 showed competition between oxide formation and its removal. These results are relevant for chemical slurry design in chemical mechanical polishing (CMP) of Ta. Further investigations were

  4. Self-assembly of linear and cyclic siloxane-containing mesogens: investigation of layered structures in bulk and thin films.

    PubMed

    Heinz, Paul; Hindelang, Konrad; Golosova, Anastasia; Papadakis, Christine M; Rieger, Bernhard

    2011-12-23

    Silicon-containing materials which possess the ability to form mesophases are promising systems for applications in the fields of electro-optical devices, nonlinear optics, and information storage media. In this work, the formation of supramolecular assemblies of a series of low molecular weight siloxane-containing mesogens is presented. Besides a novel synthesis route via Ru(II) -catalyzed hydrosilylation of phenyl acetylene derivatives, mesophase characterization by modern analysis techniques is performed. As linker groups, leading to bi- and tetramesogens, linear disiloxane and cyclic tetrasiloxane are utilized. In the resulting class of materials, high thermal stability, induced by the formation of layered smectic-type structures, is predominant. The smectic-type phases were found to be monotropic. Layer distances in the assemblies, as well as the phase transition temperatures, can be controlled by the substitution motif on the mesogens (number and length of alkyl chains). In spin-cast thin films, the layered domains are visualized by atomic force microscopy; furthermore, domain dimensions and electron densities are determined by grazing-incidence small-angle X-ray scattering.

  5. Semiconductor to metallic transition in bulk accumulated amorphous indium-gallium-zinc-oxide dual gate thin-film transistor

    SciTech Connect

    Chun, Minkyu; Chowdhury, Md Delwar Hossain; Jang, Jin

    2015-05-15

    We investigated the effects of top gate voltage (V{sub TG}) and temperature (in the range of 25 to 70 {sup o}C) on dual-gate (DG) back-channel-etched (BCE) amorphous-indium-gallium-zinc-oxide (a-IGZO) thin film transistors (TFTs) characteristics. The increment of V{sub TG} from -20V to +20V, decreases the threshold voltage (V{sub TH}) from 19.6V to 3.8V and increases the electron density to 8.8 x 10{sup 18}cm{sup −3}. Temperature dependent field-effect mobility in saturation regime, extracted from bottom gate sweep, show a critical dependency on V{sub TG}. At V{sub TG} of 20V, the mobility decreases from 19.1 to 15.4 cm{sup 2}/V ⋅ s with increasing temperature, showing a metallic conduction. On the other hand, at V{sub TG} of - 20V, the mobility increases from 6.4 to 7.5cm{sup 2}/V ⋅ s with increasing temperature. Since the top gate bias controls the position of Fermi level, the temperature dependent mobility shows metallic conduction when the Fermi level is above the conduction band edge, by applying high positive bias to the top gate.

  6. Excitation of Love waves in a thin film layer by a line source.

    NASA Technical Reports Server (NTRS)

    Tuan, H.-S.; Ponamgi, S. R.

    1972-01-01

    The excitation of a Love surface wave guided by a thin film layer deposited on a semiinfinite substrate is studied in this paper. Both the thin film and the substrate are considered to be elastically isotropic. Amplitudes of the surface wave in the thin film region and the substrate are found in terms of the strength of a line source vibrating in a direction transverse to the propagating wave. In addition to the surface wave, the bulk shear wave excited by the source is also studied. Analytical expressions for the bulk wave amplitude as a function of the direction of propagation, the acoustic powers transported by the surface and bulk waves, and the efficiency of surface wave excitation are obtained. A numerical example is given to show how the bulk wave radiation pattern depends upon the source frequency, the film thickness and other important parameters of the problem. The efficiency of surface wave excitation is also calculated for various parameter values.

  7. XPS and DFT study of pulsed Bi-implantation of bulk and thin-films of ZnO-The role of oxygen imperfections

    NASA Astrophysics Data System (ADS)

    Zatsepin, D. A.; Boukhvalov, D. W.; Gavrilov, N. V.; Kurmaev, E. Z.; Zhidkov, I. S.

    2016-11-01

    An atomic and electronic structure of the bulk and thin-film morphologies of ZnO were modified using pulsed Bi-ion implantation (1 × 1017 cm-2 fluence, 70 min exposure under Bi-ion beam, EBi+ = 30 keV, pulsed ion-current density of not more than 0.8 mA/cm2 with a repetition rate of 12.5 Hz). The final samples were qualified by X-ray photoelectron core-level and valence band mapping spectroscopy applying ASTM materials science standard. The spectroscopy data obtained was discussed on the basis of DFT-models for Bi-embedding into ZnO host-matrices. It was established that in the case of direct Bi-impurities insertion into the employed ZnO-host for both studied morphologies neither the only ;pure; Bi2O3-like phase nor the only ;pure; Bi-metal will be preferable to appear as a secondary phase. An unfavorability of the large cluster agglomeration of Bi-impurities in ZnO-hosts has been shown and an oxygen 2s electronic states pleomorphizm was surely established.

  8. Characterization of Atomic Structure, Relaxation and Phase Transformation Mechanisms in Bulk and Thin Film Amorphous Chalcogenides and Gallium Antimonide

    NASA Astrophysics Data System (ADS)

    Edwards, Trenton Gerard

    intermediate between a randomly connected and a fully clustered network of GeSe4 tetrahedra and Se chains. Additionally, a new two-dimensional NMR spectroscopic technique is developed and applied to Ge-Se glasses that allowed the separation of isotropic and anisotropic chemical shifts. Through the analysis of the anisotropic sideband pattern in the second dimension it is possible to detect up to four distinct types of Se environments in the glass structure on the basis of their characteristic chemical shift anisotropies. 125Te NMR chemical shift systematics is established for coordination environments of Te atoms in a wide range of crystalline and glassy tellurides in the Ga-As-Sb-Te system. 125Te NMR spectroscopy is then used to investigate the short-range structure of amorphous and crystalline Ge1Sb2 Te4 and Ge2Sb2Te5 phase change alloys. Both alloys are found to consist of only heteropolar Ge/Sb-Te bonds in the amorphous and crystalline state and strong vacancy clustering in the nanocrystalline state that may facilitate a rapid displacive transformation between the amorphous and crystalline states without the need of significant atomic rearrangement or diffusion. Based on these 125Te NMR results a Te-centric model of the phase change mechanism in GST alloys is proposed. Structure and phase changes in amorphous Ga-Sb alloys are studied using synchrotron x-ray diffraction and 71Ga and 121Sb NMR spectroscopy. Pressure induced phase transformations in amorphous GaSb is shown to be consistent with the existence of an underlying polyamorphic phase transition between a low and a high-density amorphous phase. NMR results for amorphous Ga46Sb54 indicate that both Ga and Sb atoms are fourfold coordinated with 40% of these atoms participating in homopolar bonding in the as-deposited film. Subsequent crystallization into the zinc blend structure therefore requires extensive bond switching and elimination of homopolar bonds. For amorphous Ga14Sb86 both Ga and Sb atoms are found to be

  9. Acoustic Transduction Materials and Devices

    DTIC Science & Technology

    1998-01-01

    are to Cymbal and Tonpilz transducer arrays for 3 - 50 kHz sonars, thin/thick film transducers for 10 - 100 MHz medical acoustic devices...Cymbal arrayed projectors, PMN Tonpilz tunable transducers , thin/thick film micro- Tonpilz transducers and controlling electronics. The Center for...emphasis is shifting to the acoustic vector sensor. Film transducers The goal is to use the tonpilz design to facilitate development of high

  10. Phase transition in bulk single crystals and thin films of VO2 by nanoscale infrared spectroscopy and imaging

    SciTech Connect

    Liu, Mengkun; Sternbach, Aaron J.; Wagner, Martin; Slusar, Tetiana V.; Kong, Tai; Bud'ko, Sergey L.; Kittiwatanakul, Salinporn; Qazilbash, M. M.; McLeod, Alexander; Fei, Zhe; Abreu, Elsa; Zhang, Jingdi; Goldflam, Michael; Dai, Siyuan; Ni, Guang -Xin; Lu, Jiwei; Bechtel, Hans A.; Martin, Michael C.; Raschke, Markus B.; Averitt, Richard D.; Wolf, Stuart A.; Kim, Hyun -Tak; Canfield, Paul C.; Basov, D. N.

    2015-06-29

    We have systematically studied a variety of vanadium dioxide (VO2) crystalline forms, including bulk single crystals and oriented thin films, using infrared (IR) near-field spectroscopic imaging techniques. By measuring the IR spectroscopic responses of electrons and phonons in VO2 with sub-grain-size spatial resolution (~20nm), we show that epitaxial strain in VO2 thin films not only triggers spontaneous local phase separations, but leads to intermediate electronic and lattice states that are intrinsically different from those found in bulk. Generalized rules of strain- and symmetry-dependent mesoscopic phase inhomogeneity are also discussed. Furthermore, these results set the stage for a comprehensive understanding of complex energy landscapes that may not be readily determined by macroscopic approaches.

  11. OSCEE fan exhaust bulk absorber treatment evaluation

    NASA Technical Reports Server (NTRS)

    Bloomer, H. E.; Samanich, N. E.

    1980-01-01

    The acoustic suppression capability of bulk absorber material designed for use in the fan exhaust duct walls of the quiet clean short haul experiment engine (OCSEE UTW) was evaluated. The acoustic suppression to the original design for the engine fan duct which consisted of phased single degree-of-freedom wall treatment was tested with a splitter and also with the splitter removed. Peak suppression was about as predicted with the bulk absorber configuration, however, the broadband characteristics were not attained. Post test inspection revealed surface oil contamination on the bulk material which could have caused the loss in bandwidth suppression.

  12. Nanomechanical and optical properties of highly a-axis oriented AlN films

    NASA Astrophysics Data System (ADS)

    Jose, Feby; Ramaseshan, R.; Tripura Sundari, S.; Dash, S.; Tyagi, A. K.; Kiran, M. S. R. N.; Ramamurty, U.

    2012-12-01

    This paper reports optical and nanomechanical properties of predominantly a-axis oriented AlN thin films. These films were deposited by reactive DC magnetron sputtering technique at an optimal target to substrate distance of 180 mm. X-ray rocking curve (FWHM = 52 arcsec) studies confirmed the preferred orientation. Spectroscopic ellipsometry revealed a refractive index of 1.93 at a wavelength of 546 nm. The hardness and elastic modulus of these films were 17 and 190 GPa, respectively, which are much higher than those reported earlier can be useful for piezoelectric films in bulk acoustic wave resonators.

  13. Strain evolution of epitaxial tetragonal-like BiFeO3 thin films on LaAlO3(001) substrates prepared by sputtering and their bulk photovoltaic effect

    NASA Astrophysics Data System (ADS)

    Nakashima, Seiji; Uchida, Tomohisa; Doi, Kentaro; Saitoh, Koh; Fujisawa, Hironori; Sakata, Osami; Katsuya, Yoshio; Tanaka, Nobuo; Shimizu, Masaru

    2016-10-01

    The structural evolution of high-quality 3.3-73.2-nm-thick tetragonal-like BiFeO3 (T-BFO) thin films grown on LaAlO3(001) substrates and the bulk photovoltaic effect of the films were investigated. The T-BFO films were grown by rf magnetron sputtering, showing the Peudellösung fringes around the T-BFO (001) diffraction peak in X-ray diffraction θ-2θ patterns. These indicate the structural coherence between the surface and the interface in the surface normal direction of the films. High-resolution synchrotron X-ray diffraction analysis and transmission electron microscopy reveal that the lattice relaxation behavior from the MA monoclinic to MC monoclinic structure occurs as the film thickness increases. The domain structure was partly controlled by using a vicinal LAO (001) substrate along [100]. Regarding the current-voltage characteristics of the Pt/T-BFO/Pt coplanar capacitor under violet laser illumination, T-BFO films show an anomalous photovoltaic effect with an open-circuit voltage of 6.1 V and a short-circuit current of -290 pA along the [100]T-BFO direction.

  14. Effect of film thickness and viscoelasticity on separability of vapour classes by wavelet and principal component analyses of polymer-coated surface acoustic wave sensor transients

    NASA Astrophysics Data System (ADS)

    Singh, Prashant; Yadava, R. D. S.

    2011-02-01

    The transient response of a polymer-coated surface acoustic wave (SAW) vapour sensor depends on partitioning and diffusion of vapour species into the polymer in conjunction with its thickness and viscoelastic properties. The shapes of transient signals carry information about vapour identities due to specificity of the partition coefficient and the diffusion coefficient. The analysis of transient signals therefore offers a simpler approach for vapour identification in comparison to conventional electronic nose systems that employ a broadly selective sensor array. The transient response-based methods are however not developed to a similar level of maturity as their sensor array counterparts. The main reason for this is associated with complex signal generation kinetics and polymer viscoelasticity. The latter is independent of vapour identities (assuming low concentrations) but influences sensor response through nonlinear dependences on polymer thickness and viscoelastic coefficients. In this paper, we endeavour to find out whether viscoelasticity and its manifestation through thickness dependences could be turned into an advantage for transient-based vapour identification. Using an established SAW sensor model with additive noise we analyse sensor transients by wavelet decomposition and principal component analysis (PCA) for various combinations of polymer thickness, viscoelastic storage and loss moduli and noise level. We calculate vapour class separability measures defined on the basis of scatter matrices of principal components of wavelet coefficients to determine the discrimination ability of sensor transients for various combinations of film thickness and viscoelastic parameters. The simulation experiments are performed by considering a polyisobutylene-coated SAW oscillator sensor under exposure to seven volatile organic compounds (chloroform, chlorobenzene, o-dichlorobenzene, n-heptane, toluene, n-hexane and n-octane). The film thicknesses are varied from thin

  15. Observation of guided longitudinal acoustic modes and nondestructive characterization of the elastic properties of hard films/coatings

    SciTech Connect

    Chirita, M.; Sooryakumar, R.; Xia, Hua; Monteiro, O. R.; Brown, I. G.

    1999-12-02

    We report on a new high frequency excitation, identified as a longitudinal guided mode, supported in a hard isotropic film deposited on a substrate. The observation of this mode allows for a direct determination of the C{sub 11} elastic constant of the film. The remaining constant, C{sub 44}, was determined through a least square fit to the dispersion of the pseudo surface wave. Properties of the observed excitations were investigated by evaluating their mode density and polarization characteristics.

  16. Bulk undercooling

    NASA Technical Reports Server (NTRS)

    Kattamis, T. Z.

    1984-01-01

    Bulk undercooling methods and procedures will first be reviewed. Measurement of various parameters which are necessary to understand the solidification mechanism during and after recalescence will be discussed. During recalescence of levitated, glass-encased large droplets (5 to 8 mm diam) high speed temperature sensing devices coupled with a rapid response oscilloscope are now being used at MIT to measure local thermal behavior in hypoeutectic and eutectic binary Ni-Sn alloys. Dendrite tip velocities were measured by various investigators using thermal sensors or high speed cinematography. The confirmation of the validity of solidification models of bulk-undercooled melts is made difficult by the fineness of the final microstructure, the ultra-rapid evolution of the solidifying system which makes measurements very awkward, and the continuous modification of the microstructure which formed during recalescence because of precipitation, remelting and rapid coarsening.

  17. Films.

    ERIC Educational Resources Information Center

    Philadelphia Board of Education, PA. Div. of Instructional Materials.

    The Affective Curriculum Research Project produced five films and two records during a series of experimental summer programs. The films and records form part of a curriculum designed to teach to the concerns of students. The films were an effort to describe the Philadelphia Cooperative Schools Program, to explain its importance, and to…

  18. Double-negative acoustic metamaterial.

    PubMed

    Li, Jensen; Chan, C T

    2004-11-01

    We show here the existence of acoustic metamaterial, in which both the effective density and bulk modulus are simultaneously negative, in the true and strict sense of an effective medium. Our double-negative acoustic system is an acoustic analogue of Veselago's medium in electromagnetism, and shares many unique consequences, such as negative refractive index. The double negativity in acoustics is derived from low-frequency resonances, as in the case of electromagnetism, but the negative density and modulus are derived from a single resonance structure as distinct from electromagnetism in which the negative permeability and negative permittivity originates from different resonance mechanisms.

  19. Acoustic Neuroma

    MedlinePlus

    ... search IRSA's site Unique Hits since January 2003 Acoustic Neuroma Click Here for Acoustic Neuroma Practice Guideline ... to microsurgery. One doctor's story of having an acoustic neuroma In August 1991, Dr. Thomas F. Morgan ...

  20. Theoretical requirements for broadband perfect absorption of acoustic waves by ultra-thin elastic meta-films

    PubMed Central

    Duan, Yuetao; Luo, Jie; Wang, Guanghao; Hang, Zhi Hong; Hou, Bo; Li, Jensen; Sheng, Ping; Lai, Yun

    2015-01-01

    We derive and numerically demonstrate that perfect absorption of elastic waves can be achieved in two types of ultra-thin elastic meta-films: one requires a large value of almost pure imaginary effective mass density and a free space boundary, while the other requires a small value of almost pure imaginary effective modulus and a hard wall boundary. When the pure imaginary density or modulus exhibits certain frequency dispersions, the perfect absorption effect becomes broadband, even in the low frequency regime. Through a model analysis, we find that such almost pure imaginary effective mass density with required dispersion for perfect absorption can be achieved by elastic metamaterials with large damping. Our work provides a feasible approach to realize broadband perfect absorption of elastic waves in ultra-thin films. PMID:26184117

  1. Theoretical requirements for broadband perfect absorption of acoustic waves by ultra-thin elastic meta-films.

    PubMed

    Duan, Yuetao; Luo, Jie; Wang, Guanghao; Hang, Zhi Hong; Hou, Bo; Li, Jensen; Sheng, Ping; Lai, Yun

    2015-07-17

    We derive and numerically demonstrate that perfect absorption of elastic waves can be achieved in two types of ultra-thin elastic meta-films: one requires a large value of almost pure imaginary effective mass density and a free space boundary, while the other requires a small value of almost pure imaginary effective modulus and a hard wall boundary. When the pure imaginary density or modulus exhibits certain frequency dispersions, the perfect absorption effect becomes broadband, even in the low frequency regime. Through a model analysis, we find that such almost pure imaginary effective mass density with required dispersion for perfect absorption can be achieved by elastic metamaterials with large damping. Our work provides a feasible approach to realize broadband perfect absorption of elastic waves in ultra-thin films.

  2. Films

    NASA Astrophysics Data System (ADS)

    Li, Ming; Zhang, Yang; Shao, Yayun; Zeng, Min; Zhang, Zhang; Gao, Xingsen; Lu, Xubing; Liu, J.-M.; Ishiwara, Hiroshi

    2014-09-01

    In this paper, we investigated the microstructure and electrical properties of Bi2SiO5 (BSO) doped SrBi2Ta2O9 (SBT) films deposited by chemical solution deposition. X-ray diffraction observation indicated that the crystalline structures of all the BSO-doped SBT films are nearly the same as those of a pure SBT film. Through BSO doping, the 2Pr and 2Ec values of SBT films were changed from 15.3 μC/cm2 and 138 kV/cm of pure SBT to 1.45 μC/cm2 and 74 kV/cm of 10 wt.% BSO-doped SBT. The dielectric constant at 1 MHz for SBT varied from 199 of pure SBT to 96 of 10 wt.% BSO-doped SBT. The doped SBT films exhibited higher leakage current than that of non-doped SBT films. Nevertheless, all the doped SBT films still had small dielectric loss and low leakage current. Our present work will provide useful insights into the BSO doping effects to the SBT films, and it will be helpful for the material design in the future nonvolatile ferroelectric memories.

  3. Effects of working pressure and annealing on bulk density and nanopore structures in amorphous In-Ga-Zn-O thin-film transistors

    NASA Astrophysics Data System (ADS)

    Ide, Keisuke; Kikuchi, Mitsuho; Ota, Masato; Sasase, Masato; Hiramatsu, Hidenori; Kumomi, Hideya; Hosono, Hideo; Kamiya, Toshio

    2017-03-01

    Microstructures of amorphous In-Ga-Zn-O (a-IGZO) thin films of different densities were analyzed. Device-quality a-IGZO films were deposited under optimum conditions, e.g., the total pressure P tot = 0.55 Pa produced high film densities of ˜6.1 g/cm3, while a very high P tot = 5.0 Pa produced low film densities of 5.5 g/cm3. Both films formed uniform high-density layers in the vicinity of the glass substrate, 10-20 nm in thickness depending on P tot, while their growth mode changed to a sparse columnar structure in thicker regions. X-ray reflectivity and in situ spectroscopic ellipsometry provided different results on densification by post deposition thermal annealing; i.e., the latter has a higher sensitivity. High-Z-contrast images obtained by high-angle annular dark-field scanning transmission electron microscopy were also useful for detecting nanometer-size non uniformity even in device-quality a-IGZO films.

  4. Strain engineered barium strontium titanate for tunable thin film resonators

    SciTech Connect

    Khassaf, H.; Khakpash, N.; Sun, F.; Sbrockey, N. M.; Tompa, G. S.; Kalkur, T. S.; Alpay, S. P.

    2014-05-19

    Piezoelectric properties of epitaxial (001) barium strontium titanate (BST) films are computed as functions of composition, misfit strain, and temperature using a non-linear thermodynamic model. Results show that through adjusting in-plane strains, a highly adaptive rhombohedral ferroelectric phase can be stabilized at room temperature with outstanding piezoelectric response exceeding those of lead based piezoceramics. Furthermore, by adjusting the composition and the in-plane misfit, an electrically tunable piezoelectric response can be obtained in the paraelectric state. These findings indicate that strain engineered BST films can be utilized in the development of electrically tunable and switchable surface and bulk acoustic wave resonators.

  5. Identifying barriers to charge-carriers in the bulk and surface regions of Cu2ZnSnS4 nanocrystal films by x-ray absorption fine structures (XAFSs)

    NASA Astrophysics Data System (ADS)

    Turnbull, Matthew J.; Vaccarello, Daniel; Yiu, Yun Mui; Sham, Tsun-Kong; Ding, Zhifeng

    2016-11-01

    Solar cell performance is most affected by the quality of the light absorber layer. For thin-film devices, this becomes a two-fold problem of maintaining a low-cost design with well-ordered nanocrystal (NC) structure. The use of Cu2ZnSnS4 (CZTS) NCs as the light absorber films forms an ideal low-cost design, but the quaternary structure makes it difficult to maintain a well-ordered layer without the use of high-temperature treatments. There is little understanding of how CZTS NC structures affect the photoconversion efficiency, the charge-carriers, and therefore the performance of the device manufactured from it. To examine these relationships, the measured photoresponse from the photo-generation of charge-carrier electron-hole pairs was compared against the crystal structure, as short-range and long-range crystal orders for the films. The photoresponse simplifies the electronic properties into three basic steps that can be associated with changes in energy levels within the band structure. These changes result in the formation of barriers to charge-carrier flow. The extent of these barriers was determined using synchrotron-based X-ray absorbance fine structure to probe the individual metal centers in the film, and comparing these to molecular simulations of the ideal extended x-ray absorbance fine structure scattering. This allowed for the quantification of bond lengths, and thus an interpretation of the distortions in the crystal lattice. The various characteristics of the photoresponse were then correlated to the crystallographic order and used to gain physical insight into barriers to charge-carriers in the bulk and surface regions of CZTS films.

  6. Identifying barriers to charge-carriers in the bulk and surface regions of Cu2ZnSnS4 nanocrystal films by x-ray absorption fine structures (XAFSs).

    PubMed

    Turnbull, Matthew J; Vaccarello, Daniel; Yiu, Yun Mui; Sham, Tsun-Kong; Ding, Zhifeng

    2016-11-28

    Solar cell performance is most affected by the quality of the light absorber layer. For thin-film devices, this becomes a two-fold problem of maintaining a low-cost design with well-ordered nanocrystal (NC) structure. The use of Cu2ZnSnS4 (CZTS) NCs as the light absorber films forms an ideal low-cost design, but the quaternary structure makes it difficult to maintain a well-ordered layer without the use of high-temperature treatments. There is little understanding of how CZTS NC structures affect the photoconversion efficiency, the charge-carriers, and therefore the performance of the device manufactured from it. To examine these relationships, the measured photoresponse from the photo-generation of charge-carrier electron-hole pairs was compared against the crystal structure, as short-range and long-range crystal orders for the films. The photoresponse simplifies the electronic properties into three basic steps that can be associated with changes in energy levels within the band structure. These changes result in the formation of barriers to charge-carrier flow. The extent of these barriers was determined using synchrotron-based X-ray absorbance fine structure to probe the individual metal centers in the film, and comparing these to molecular simulations of the ideal extended x-ray absorbance fine structure scattering. This allowed for the quantification of bond lengths, and thus an interpretation of the distortions in the crystal lattice. The various characteristics of the photoresponse were then correlated to the crystallographic order and used to gain physical insight into barriers to charge-carriers in the bulk and surface regions of CZTS films.

  7. Highly c-axis oriented growth of GaN film on sapphire (0001) by laser molecular beam epitaxy using HVPE grown GaN bulk target

    SciTech Connect

    Kushvaha, S. S.; Kumar, M. Senthil; Maurya, K. K.; Dalai, M. K.; Sharma, Nita D.

    2013-09-15

    Growth temperature dependant surface morphology and crystalline properties of the epitaxial GaN layers grown on pre-nitridated sapphire (0001) substrates by laser molecular beam epitaxy (LMBE) were investigated in the range of 500–750 °C. The grown GaN films were characterized using high resolution x-ray diffraction, atomic force microscopy (AFM), micro-Raman spectroscopy, and secondary ion mass spectroscopy (SIMS). The x-ray rocking curve full width at a half maximum (FWHM) value for (0002) reflection dramatically decreased from 1582 arc sec to 153 arc sec when the growth temperature was increased from 500 °C to 600 °C and the value further decreased with increase of growth temperature up to 720 °C. A highly c-axis oriented GaN epitaxial film was obtained at 720 °C with a (0002) plane rocking curve FWHM value as low as 102 arc sec. From AFM studies, it is observed that the GaN grain size also increased with increasing growth temperature and flat, large lateral grains of size 200-300 nm was obtained for the film grown at 720 °C. The micro-Raman spectroscopy studies also exhibited the high-quality wurtzite nature of GaN film grown on sapphire at 720 °C. The SIMS measurements revealed a non-traceable amount of background oxygen impurity in the grown GaN films. The results show that the growth temperature strongly influences the surface morphology and crystalline quality of the epitaxial GaN films on sapphire grown by LMBE.

  8. Highly c-axis oriented growth of GaN film on sapphire (0001) by laser molecular beam epitaxy using HVPE grown GaN bulk target

    NASA Astrophysics Data System (ADS)

    Kushvaha, S. S.; Kumar, M. Senthil; Maurya, K. K.; Dalai, M. K.; Sharma, Nita D.

    2013-09-01

    Growth temperature dependant surface morphology and crystalline properties of the epitaxial GaN layers grown on pre-nitridated sapphire (0001) substrates by laser molecular beam epitaxy (LMBE) were investigated in the range of 500-750 °C. The grown GaN films were characterized using high resolution x-ray diffraction, atomic force microscopy (AFM), micro-Raman spectroscopy, and secondary ion mass spectroscopy (SIMS). The x-ray rocking curve full width at a half maximum (FWHM) value for (0002) reflection dramatically decreased from 1582 arc sec to 153 arc sec when the growth temperature was increased from 500 °C to 600 °C and the value further decreased with increase of growth temperature up to 720 °C. A highly c-axis oriented GaN epitaxial film was obtained at 720 °C with a (0002) plane rocking curve FWHM value as low as 102 arc sec. From AFM studies, it is observed that the GaN grain size also increased with increasing growth temperature and flat, large lateral grains of size 200-300 nm was obtained for the film grown at 720 °C. The micro-Raman spectroscopy studies also exhibited the high-quality wurtzite nature of GaN film grown on sapphire at 720 °C. The SIMS measurements revealed a non-traceable amount of background oxygen impurity in the grown GaN films. The results show that the growth temperature strongly influences the surface morphology and crystalline quality of the epitaxial GaN films on sapphire grown by LMBE.

  9. Linear degrees of freedom in speech production: analysis of cineradio- and labio-film data and articulatory-acoustic modeling.

    PubMed

    Beautemps, D; Badin, P; Bailly, G

    2001-05-01

    The following contribution addresses several issues concerning speech degrees of freedom in French oral vowels, stop, and fricative consonants based on an analysis of tongue and lip shapes extracted from cineradio- and labio-films. The midsagittal tongue shapes have been submitted to a linear decomposition where some of the loading factors were selected such as jaw and larynx position while four other components were derived from principal component analysis (PCA). For the lips, in addition to the more traditional protrusion and opening components, a supplementary component was extracted to explain the upward movement of both the upper and lower lips in [v] production. A linear articulatory model was developed; the six tongue degrees of freedom were used as the articulatory control parameters of the midsagittal tongue contours and explained 96% of the tongue data variance. These control parameters were also used to specify the frontal lip width dimension derived from the labio-film front views. Finally, this model was complemented by a conversion model going from the midsagittal to the area function, based on a fitting of the midsagittal distances and the formant frequencies for both vowels and consonants.

  10. Observation of the nonlinear meissner effect in YBCO thin films: evidence for a D-wave order parameter in the bulk of the cuprate superconductors.

    PubMed

    Oates, D E; Park, S-H; Koren, G

    2004-11-05

    We present experimental evidence for the observation of the nonlinear Meissner effect in high-quality epitaxial yttrium barium copper oxide thin films by measuring their intermodulation distortion at microwave frequencies versus temperature. Most of the films measured show a characteristic increase in nonlinearity at low temperatures as predicted by the nonlinear Meissner effect. We could measure the nonlinear Meissner effect because intermodulation distortion measurements are an extremely sensitive method that can detect changes in the penetration depth of the order of 1 part in 10(5).

  11. Influence of static and dynamic dipolar fields in bulk YIG/thin film NiFe systems probed via spin rectification effect

    NASA Astrophysics Data System (ADS)

    Soh, Wee Tee; Tay, Z. J.; Yakovlev, N. L.; Peng, Bin; Ong, C. K.

    2017-03-01

    The characteristics of the static and dynamic components of the dipolar fields originating from a bulk polycrystalline yttrium iron garnet (YIG) substrate are probed by depositing a NiFe (Permalloy) layer on it, which acts as a detector. By measuring dc voltages generated via spin rectification effect (SRE) within the NiFe layer under microwave excitation, we characterize the influence of dipolar fields from bulk YIG on the NiFe layer. It is found that the dynamic YIG dipolar fields modify the self-SRE of NiFe, driving its own rectification voltages within the NiFe layer, an effect we term as non-local SRE. This non-local SRE only occurs near the simultaneous resonance of both YIG and NiFe. On the other hand, the static dipolar field from YIG manifests itself as a negative anisotropy in the NiFe layer which shifts the latter's ferromagnetic resonance frequency.

  12. A comprehensive study on the effects of temperature, surface age, added surfactant, salinity, and bulk viscosity on coalescence time, film rigidity, and interfacial tension: Topical report

    SciTech Connect

    Peru, D.A.; Lorenz, P.B.

    1988-01-01

    The interfacial behavior of a Wilmington crude oil was studied as part of our investigations of enhanced oil recovery by weakly alkaline solutions. For some systems, the spinning drop appratus can be used to measure transient interfacial tension (IFT) effects, coalescence times of oil drops, and film rigidity simultaneously, for rapid screening of chemical slug composition for the potential of improving oil recovery by the mechanisms of oil mobilization and oil bank formation. The experimental results presented include the effects of temperature, surface age, salinity, added surfactant, and polymer on coalescence time, film rigidity, and IFT behavior. Oil displacement tests were performed using surfactant-enhanced bicarbonte solutions formulated for improved mobility control and for improved oil mobilization and oil drop coalescence. The most significant result of this work was that we were able to measure the dynamics in IFT between 2 coalescing oil drops as perturbations in the equilibrium concentration of surfactant at the interface occurred during film drainage. The accuracy of the technique for measuring IFT and film rigidity improved as the contact radii between the oil drops increased. 17 refs., 13 figs., 11 tabs.

  13. Acoustic Absorption in Porous Materials

    NASA Technical Reports Server (NTRS)

    Kuczmarski, Maria A.; Johnston, James C.

    2011-01-01

    An understanding of both the areas of materials science and acoustics is necessary to successfully develop materials for acoustic absorption applications. This paper presents the basic knowledge and approaches for determining the acoustic performance of porous materials in a manner that will help materials researchers new to this area gain the understanding and skills necessary to make meaningful contributions to this field of study. Beginning with the basics and making as few assumptions as possible, this paper reviews relevant topics in the acoustic performance of porous materials, which are often used to make acoustic bulk absorbers, moving from the physics of sound wave interactions with porous materials to measurement techniques for flow resistivity, characteristic impedance, and wavenumber.

  14. Acoustic Neuroma

    MedlinePlus

    An acoustic neuroma is a benign tumor that develops on the nerve that connects the ear to the brain. ... can press against the brain, becoming life-threatening. Acoustic neuroma can be difficult to diagnose, because the ...

  15. Depositing bulk or micro-scale electrodes

    DOEpatents

    Shah, Kedar G.; Pannu, Satinderpall S.; Tolosa, Vanessa; Tooker, Angela C.; Sheth, Heeral J.; Felix, Sarah H.; Delima, Terri L.

    2016-11-01

    Thicker electrodes are provided on microelectronic device using thermo-compression bonding. A thin-film electrical conducting layer forms electrical conduits and bulk depositing provides an electrode layer on the thin-film electrical conducting layer. An insulating polymer layer encapsulates the electrically thin-film electrical conducting layer and the electrode layer. Some of the insulating layer is removed to expose the electrode layer.

  16. Acoustic Seaglider

    DTIC Science & Technology

    2008-03-07

    a national naval responsibility. Acoustic sensors on mobile, autonomous platforms will enable basic research topics on temporal and spatial...problem and acoustic navigation and communications within the context of distributed autonomous persistent undersea surveillance sensor networks...Acoustic sensors on mobile, autonomous platforms will enable basic research topics on temporal and spatial coherence and the description of ambient

  17. Acoustic seal

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M. (Inventor)

    2006-01-01

    The invention relates to a sealing device having an acoustic resonator. The acoustic resonator is adapted to create acoustic waveforms to generate a sealing pressure barrier blocking fluid flow from a high pressure area to a lower pressure area. The sealing device permits noncontacting sealing operation. The sealing device may include a resonant-macrosonic-synthesis (RMS) resonator.

  18. Acoustic Seal

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M. (Inventor)

    2006-01-01

    The invention relates to a sealing device having an acoustic resonator. The acoustic resonator is adapted to create acoustic waveforms to generate a sealing pressure barrier blocking fluid flow from a high pressure area to a lower pressure area. The sealing device permits noncontacting sealing operation. The sealing device may include a resonant-macrosonic-synthesis (RMS) resonator.

  19. Deep-level defects related to the emissive pits in thick InGaN films on GaN template and bulk substrates

    NASA Astrophysics Data System (ADS)

    Sumiya, Masatomo; Toyomitsu, Naoki; Nakano, Yoshitaka; Wang, Jianyu; Harada, Yoshitomo; Sang, Liwen; Sekiguchi, Takashi; Yamaguchi, Tomohiro; Honda, Tohru

    2017-01-01

    We studied the emissive pits in InGaN films grown on compressive and strain-free GaN underlying layers. Pit density decreased with the full width at half maximum of ω(0002) of InGaN. The films grew on compressive and strain-free GaN underlying layers with spiral and step-flow modes, respectively. Carbon impurities accumulated inside the pits. Comparison of cathodoluminescence inside the pits and steady-state photocapacitance spectra showed that the energy level of the carbon impurities appeared at ˜2.8 eV below the conduction band (Ec) for both types of pits. Deep-level defects at Ec -2.4 eV resulting in green fluorescence emission were considered to originate from pits related to screw dislocations.

  20. A Semi-Empirical Multi-Scale Dynamic Monte Carlo Model of Organic Photovoltaic Performance in RIR-MAPLE Bulk Heterojunction Films

    NASA Astrophysics Data System (ADS)

    Stiff-Roberts, Adrienne; Atewologun, Ayomide

    A semi-empirical method for investigating the performance of OPVs in resonant infrared, matrix-assisted pulsed laser evaporation (RIR-MAPLE) films is explored. Emulsion-based RIR-MAPLE offers a unique experimental backdrop for investigating trends through simulation and gaining a better understanding of how different thin film characteristics impact OPV device performance. A novel multi-scale formulation of the Dynamic Monte Carlo (DMC) model is developed based on observable morphology features. Specifically, using confocal microscopy, we observe the presence of micro-scale regimes of pure materials and nano-scale regions of the composite blend. This enables us to assign weighted percentages to DMC implementations on two different scales: the microscale and nanoscale regions. In addition to this, we use input simulation parameters acquired by characterization of as-deposited films. The semi-empirical multi-scale model presented serves as a unique simulation opportunity for exploring different properties of RIR-MAPLE deposited OPVs, their effects on OPV performance and potential design routes for improving device efficiencies. This work was supported, in part, by the Office of Naval Research under Grant N00014-10-1-0481 and the NSF Triangle MRSEC on Soft Matter.

  1. Properties of II-VI Semiconductors: Bulk Crystals, Epitaxial Films, Quantum Well Structures, and Dilute Magnetic Systems. Materials Research Society Symposium Proceedings. Volume 161

    DTIC Science & Technology

    1990-11-21

    BULK CdTe P.M. AMIRTHARAJ AND N.K. DHAR U.S. Army Center for Night Vision and Electro-Optics Fort Belvoir, VA-22060 ABSTRACT The native defects...those that contain exposed surfaces. ACKNOWLEDGEMENT The authors wish to acknowledge Mr. Philip R. Boyd of the U.S. Army Center for Night Vision and...del IPN. Apdo. Postal 14-740, 07000 Mexico, D. F. +Departamento de Fisica del Instituto de Ciencias, Universidad Aut6noma de Puebla , Apdo. Postal J-48

  2. Dependence of Device Characteristics of Bulk-Heterojunction Organic Thin-Film Solar Cells on Concentration of Glycerol and Sorbitol Addition in Pedot:. PSS Solutions for Fabricating Buffer Layers

    NASA Astrophysics Data System (ADS)

    Yamaki, Yusuke; Marumoto, Kazuhiro; Fujimori, Takuya; Mori, Tatsuo

    We have investigated the dependence of device characteristics of bulk-heterojunction organic thin-film solar cells on the concentration of glycerol and sorbitol addition in poly(3,4-ethylenedioxy thiophene):poly(4-styrene sulfonate) (PEDOT:PSS) solutions for fabricating buffer layers. The device structure is ITO/buffer/regioregular poly(3-hexylthiophene) (P3HT):[6,6]-phenyl C61-butyric acid methylester (PCBM)/Al. Glycerol addition is effective for increasing power conversion efficiency (PCE) from 1.25 to 1.41% because of the increase in short-circuit current density (Jsc) without decreasing open-circuit voltage (Voc). On the other hand, sorbitol addition decreases PCE from 1.25 to 1.04%, owing to the decrease in Voc. This difference in Voc behavior is ascribed to different work function of PEDOT:PSS with glycerol and sorbitol treatment.

  3. Applications of bulk high-temperature superconductors

    NASA Astrophysics Data System (ADS)

    Hull, J. R.

    The development of high-temperature superconductors (HTS's) can be broadly generalized into thin-film electronics, wire applications, and bulk applications. We consider bulk HTS's to include sintered or crystallized forms that do not take the geometry of filaments or tapes, and we discuss major applications for these materials. For the most part applications may be realized with the HTS's cooled to 77 K, and the properties of the bulk HTS's are often already sufficient for commercial use. A non-exhaustive list of applications for bulk HTS's includes trapped field magnets, hysteresis motors, magnetic shielding, current leads, and magnetic bearings. These applications are briefly discussed in this paper.

  4. Lattice dynamics in elemental modulated Sb 2 Te 3 films: Lattice dynamics in elemental modulated Sb 2 Te 3 films

    SciTech Connect

    Bessas, D.; Winkler, M.; Sergueev, I.; König, J. D.; Böttner, H.; Hermann, R. P.

    2015-09-03

    We investigate the crystallinity and the lattice dynamics in elemental modulated Sbinline imageTeinline image films microscopically using high energy synchrotron radiation diffraction combined with inline imageSb nuclear inelastic scattering. The correlation length is found to be finite but less than 100 . Moreover, the element specific density of phonon states is extracted. A comparison with the element specific density of phonon states in bulk Sbinline imageTeinline image confirms that the main features in the density of phonon states arise from the layered structure. The average speed of sound at inline image inline image, is almost the same compared to bulk Sbinline imageTeinline image at inline image, inline image. Similarly, the change in the acoustic cut-off energy is within the experimental detection limit. Therefore, we suggest that the lattice thermal conductivity in elemental modulated Sbinline imageTeinline image films should not be significantly changed from its bulk value.

  5. Lattice-Latching Effect in Metalorganic Vapor Phase Epitaxy Growth of InGaAsN Film Lattice-Matched to Bulk InGaAs Substrate

    NASA Astrophysics Data System (ADS)

    Sanorpim, Sakuntam; Katayama, Ryuji; Onabe, Kentaro; Usami, Noritaka; Nakajima, Kazuo

    2010-04-01

    The effects of lattice mismatch between an InzGa1-zAs bulk substrate and an InxGa1-xAs1-yNy epilayer on the incorporation kinetics of N (y) and In (x) were investigated. Compositions (x,y) were revealed to be pinned by the substrate to those satisfying lattice-matching conditions. With decreasing In (z) content in the substrate, the incorporation of N is spontaneously enhanced. On the other hand, the In content of the layer is reduced to decrese the deformation energy due to the lattice mismatch. On the basis of our results, thick InxGa1-xAs1-yNy (0.289 < x < 0.312 and 0.009 < y < 0.014) layers exhibiting photoluminescence in the wavelength range of 1.3-1.55 µm were observed to grow owing to the “lattice-latching” effect.

  6. Using volatile additives to alter the morphology and performance of active layers in thin-film molecular photovoltaic devices incorporating bulk heterojunctions.

    PubMed

    Dang, Minh Trung; Wuest, James D

    2013-12-07

    Thin-film photovoltaic devices composed of polymers or small molecules have an exciting future as sources of renewable energy because they can be made in large sizes on flexible surfaces by inexpensive techniques of fabrication. Significant progress in developing new molecular photovoltaic materials and device architectures has been achieved in the last decade. The identity of molecular components in active layers and their individual optoelectronic properties obviously help determine the properties of devices; in addition, however, the behavior of devices depends critically on the nature of the local organization of the components. Recent studies have shown that the morphology of active layers can be tuned by adjusting various parameters, including the solvent used to cast the layer, thermal annealing, and special processing additives. In this review, we summarize the effect of volatile additives on the nanoscale morphology of molecular blends, and we show how these effects can improve the performance of devices. Although we focus on the behavior of mixtures of the type used in current molecular thin-film photovoltaic devices, the subject of our review will interest researchers in all areas of science and technology requiring materials in which separate phases must form intimate long-lived intermixtures with defined structures.

  7. Bulk chlorine uptake by polyamide active layers of thin-film composite membranes upon exposure to free chlorine-kinetics, mechanisms, and modeling.

    PubMed

    Powell, Joshua; Luh, Jeanne; Coronell, Orlando

    2014-01-01

    We studied the volume-averaged chlorine (Cl) uptake into the bulk region of the aromatic polyamide active layer of a reverse osmosis membrane upon exposure to free chlorine. Volume-averaged measurements were obtained using Rutherford backscattering spectrometry with samples prepared at a range of free chlorine concentrations, exposure times, and mixing, rinsing, and pH conditions. Our volume-averaged measurements complement previous studies that have quantified Cl uptake at the active layer surface (top ≈ 7 nm) and advance the mechanistic understanding of Cl uptake by aromatic polyamide active layers. Our results show that surface Cl uptake is representative of and underestimates volume-averaged Cl uptake under acidic conditions and alkaline conditions, respectively. Our results also support that (i) under acidic conditions, N-chlorination followed by Orton rearrangement is the dominant Cl uptake mechanism with N-chlorination as the rate-limiting step; (ii) under alkaline conditions, N-chlorination and dechlorination of N-chlorinated amide links by hydroxyl ion are the two dominant processes; and (iii) under neutral pH conditions, the rates of N-chlorination and Orton rearrangement are comparable. We propose a kinetic model that satisfactorily describes Cl uptake under acidic and alkaline conditions, with the largest discrepancies between model and experiment occurring under alkaline conditions at relatively high chlorine exposures.

  8. Microfluidic device for acoustic cell lysis

    SciTech Connect

    Branch, Darren W.; Cooley, Erika Jane; Smith, Gennifer Tanabe; James, Conrad D.; McClain, Jaime L.

    2015-08-04

    A microfluidic acoustic-based cell lysing device that can be integrated with on-chip nucleic acid extraction. Using a bulk acoustic wave (BAW) transducer array, acoustic waves can be coupled into microfluidic cartridges resulting in the lysis of cells contained therein by localized acoustic pressure. Cellular materials can then be extracted from the lysed cells. For example, nucleic acids can be extracted from the lysate using silica-based sol-gel filled microchannels, nucleic acid binding magnetic beads, or Nafion-coated electrodes. Integration of cell lysis and nucleic acid extraction on-chip enables a small, portable system that allows for rapid analysis in the field.

  9. RETRACTED: Size-controlled spherical polymer nanoparticles: synthesis with tandem acoustic emulsification followed by soap-free emulsion polymerization and one-step fabrication of colloidal crystal films of various colors.

    PubMed

    Hirai, Yuki; Nakabayashi, Koji; Kojima, Maya; Atobe, Mahito

    2014-11-01

    We have developed a novel synthesis method for size-controlled polymer nanoparticles using soap-free emulsion polymerization. This new synthetic method involves sequential ultrasonic irradiation (20kHz→500kHz→1.6MHz→2.4MHz) for acoustic emulsification of a water-insoluble monomer such as methylmethacrylate (MMA) in an aqueous medium, followed by emulsion polymerization in the obtained solution without using any surfactants. The sequential ultrasonication (tandem acoustic emulsification) could provide a clear and stable emulsified solution containing monomer droplets with relatively narrow size distribution in the nanometer range. The subsequent polymerization in this solution yielded size-controlled polymethylmethacrylate (PMMA) nanoparticles and monodisperse PMMA nanoparticles of different sizes. Furthermore, colloidal crystal films could be easily prepared from the as-polymerized nanoparticle solution using the fluidic-cell method. Moreover, we succeeded to modify the structural color of colloidal crystal films by the addition of a small amount of organic solvent to the as-polymerized nanoparticle solution for the fluidic-cell method.

  10. A Spherically-Shaped PZT Thin Film Ultrasonic Transducer with an Acoustic Impedance Gradient Matching Layer Based on a Micromachined Periodically Structured Flexible Substrate

    PubMed Central

    Feng, Guo-Hua; Liu, Wei-Fan

    2013-01-01

    This paper presents the microfabrication of an acoustic impedance gradient matching layer on a spherically-shaped piezoelectric ultrasonic transducer. The acoustic matching layer can be designed to achieve higher acoustic energy transmission and operating bandwidth. Also included in this paper are a theoretical analysis of the device design and a micromachining technique to produce the novel transducer. Based on a design of a lead titanium zirconium (PZT) micropillar array, the constructed gradient acoustic matching layer has much better acoustic transmission efficiency within a 20–50 MHz operation range compared to a matching layer with a conventional quarter-wavelength thickness Parylene deposition. To construct the transducer, periodic microcavities are built on a flexible copper sheet, and then the sheet forms a designed curvature with a ball shaping. After PZT slurry deposition, the constructed PZT micropillar array is released onto a curved thin PZT layer. Following Parylene conformal coating on the processed PZT micropillars, the PZT micropillars and the surrounding Parylene comprise a matching layer with gradient acoustic impedance. By using the proposed technique, the fabricated transducer achieves a center frequency of 26 MHz and a −6 dB bandwidth of approximately 65%. PMID:24113683

  11. Determination of near-surface material properties by line-focus acoustic microscopy

    SciTech Connect

    Achenbach, J.D.; Li, W.

    1996-12-31

    A line-focus acoustic microscope is used in conjunction with a multiple wave-mode method to determine elastic constants from a single V(z) measurement. V(z) curves which include contributions from different wave modes, measured using the line-focus acoustic microscope at 225 MHz, have been compared with theoretical results predicted by a V(z) measurement model. The determination of elastic constants has been achieved numerically by seeking a set of elastic constants that leads to the best fit, in the least square sense, of the theoretical results to the experimental ones. The method has been applied to isotropic materials in bulk, and plate and thin-film configurations. Elastic constants for each of these cases have been determined. The consistency, convergence, sensitivity and accuracy of the procedure have been investigated.

  12. Influences of Crystalline Anisotropy, Doping, Porosity, and Connectivity on the Critical Current Densities of Superconducting Magnesium Diboride Bulks, Wires, and Thin Films

    NASA Astrophysics Data System (ADS)

    Susner, Michael Adam

    Magnesium diboride (MgB2) is a material with a superconducting transition temperature of 39 K. Discovered in 2001, the relatively large coherence length (and associated lack of weak links) together with its simple binary composition (making phase pure formation relatively easy) have made it a material of substantial interest. However, it has been difficult to assess in detail the relative importance of the roles of flux pinning, crystalline anisotropy, porosity, connectivity, doping, and doping homogeneity on the observed transport limitations of this conductor. This work focused on deconvoluting the most dominant of these effects. First, the overall effects of electrical connectivity and crystalline anisotropy of critical current density (Jc) were investigated. In doing so the Jcs of dense, well-connected c-axis oriented films were compared with the relatively degraded Jcs of standard powder-in-tube MgB2 wires. With the aid of a percolation model it was deduced that at 4.2 K, 10 T. about 60% of the degradation was due to MgB2’s crystalline anisotropy and the remaining 40% to porosity. Second, chemical substitutions onto both the Mg and B sites were investigated in terms of effects on structure and superconducting properties. The homogeneity of C-substitution onto the B site was quantified in terms of the width of the superconducting specific heat transition. Analysis of the results led to optimization of methods for homogeneous doping of C into the B sublattice. Zr substituted onto the Mg sublattice was investigated using samples prepared by pulsed laser deposition (PLD). Changes in magnetic, resistive, superconductive, chemical, and structural properties were studied over a wide range of Zr composition.

  13. Musical Acoustics

    NASA Astrophysics Data System (ADS)

    Gough, Colin

    This chapter provides an introduction to the physical and psycho-acoustic principles underlying the production and perception of the sounds of musical instruments. The first section introduces generic aspects of musical acoustics and the perception of musical sounds, followed by separate sections on string, wind and percussion instruments.

  14. Acoustic Climb to Cruise Test

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Flight test film footage of three different aircraft testing the acoustical noise levels during take-off, climb, maneuvers, and touch and go landings are described. These sound tests were conducted on two fighter aircraft and one cargo aircraft. Results from mobile test vehicle are shown.

  15. Acoustic waves in medical imaging and diagnostics.

    PubMed

    Sarvazyan, Armen P; Urban, Matthew W; Greenleaf, James F

    2013-07-01

    Up until about two decades ago acoustic imaging and ultrasound imaging were synonymous. The term ultrasonography, or its abbreviated version sonography, meant an imaging modality based on the use of ultrasonic compressional bulk waves. Beginning in the 1990s, there started to emerge numerous acoustic imaging modalities based on the use of a different mode of acoustic wave: shear waves. Imaging with these waves was shown to provide very useful and very different information about the biological tissue being examined. We discuss the physical basis for the differences between these two basic modes of acoustic waves used in medical imaging and analyze the advantages associated with shear acoustic imaging. A comprehensive analysis of the range of acoustic wavelengths, velocities and frequencies that have been used in different imaging applications is presented. We discuss the potential for future shear wave imaging applications.

  16. Rotary bulk solids divider

    DOEpatents

    Maronde, Carl P.; Killmeyer, Jr., Richard P.

    1992-01-01

    An apparatus for the disbursement of a bulk solid sample comprising, a gravity hopper having a top open end and a bottom discharge end, a feeder positioned beneath the gravity hopper so as to receive a bulk solid sample flowing from the bottom discharge end, and a conveyor receiving the bulk solid sample from the feeder and rotating on an axis that allows the bulk solid sample to disperse the sample to a collection station.

  17. ROTARY BULK SOLIDS DIVIDER

    DOEpatents

    Maronde, Carl P.; Killmeyer JR., Richard P.

    1992-03-03

    An apparatus for the disbursement of a bulk solid sample comprising, a gravity hopper having a top open end and a bottom discharge end, a feeder positioned beneath the gravity hopper so as to receive a bulk solid sample flowing from the bottom discharge end, and a conveyor receiving the bulk solid sample from the feeder and rotating on an axis that allows the bulk solid sample to disperse the sample to a collection station.

  18. Room Acoustics

    NASA Astrophysics Data System (ADS)

    Kuttruff, Heinrich; Mommertz, Eckard

    The traditional task of room acoustics is to create or formulate conditions which ensure the best possible propagation of sound in a room from a sound source to a listener. Thus, objects of room acoustics are in particular assembly halls of all kinds, such as auditoria and lecture halls, conference rooms, theaters, concert halls or churches. Already at this point, it has to be pointed out that these conditions essentially depend on the question if speech or music should be transmitted; in the first case, the criterion for transmission quality is good speech intelligibility, in the other case, however, the success of room-acoustical efforts depends on other factors that cannot be quantified that easily, not least it also depends on the hearing habits of the listeners. In any case, absolutely "good acoustics" of a room do not exist.

  19. Drag Measurements of Porous Plate Acoustic Liners

    NASA Technical Reports Server (NTRS)

    Wolter, John D.

    2005-01-01

    This paper presents the results of direct drag measurements on a variety of porous plate acoustic liners. The existing literature describes numerous studies of drag on porous walls with injection or suction, but relatively few of drag on porous plates with neither injection nor suction. Furthermore, the porosity of the porous plate in existing studies is much lower than typically used in acoustic liners. In the present work, the acoustic liners consisted of a perforated face sheet covering a bulk acoustic absorber material. Factors that were varied in the experiment were hole diameter, hole pattern, face sheet thickness, bulk material type, and size of the gap (if any) between the face sheet and the absorber material.

  20. Setup for high-temperature surface Brillouin light scattering: Application to opaque thin films and coatings

    NASA Astrophysics Data System (ADS)

    Faurie, D.; Girodon-Boulandet, N.; Kaladjian, A.; Challali, F.; Abadias, G.; Djemia, P.

    2017-02-01

    A setup combining surface Brillouin light scattering with a high-temperature chamber has been developed. The temperature of the sample is controlled with a Bühler HDK chamber for optical measurements (maximum temperature of 1600 °C), in controlled atmospheres or high vacuum (10-6 mbar). This setup allows the study of sound velocity of surface acoustic waves and of the elastic constants of opaque thin films and coatings in situ as a function of temperature from surface Brillouin light scattering, by analyzing the backscattered light from the sample at a fixed angle of incidence. In this paper, we will demonstrate the applications of this setup for metallic glass thin films devitrification study and evaluation of high temperature elastic properties of hard nitride coatings. This kind of study using surface acoustic waves is rare, in contrast to those made on transparent bulk materials.

  1. High Q Miniature Sapphire Acoustic Resonator

    NASA Technical Reports Server (NTRS)

    Wang, Rabi T.; Tjoelker, R. L.

    2010-01-01

    We have demonstrated high Q measurements in a room temperature Miniature Sapphire Acoustic Resonator (MSAR). Initial measurements of bulk acoustic modes in room temperature sapphire at 39 MHz have demonstrated a Q of 8.8 x 10(exp 6). The long term goal of this work is to integrate such a high Q resonator with small, low noise quartz oscillator electronics, providing a fractional frequency stability better than 1 x 10(exp -14) @ 1s.

  2. Prototype acoustic resonance spectroscopy monitor

    SciTech Connect

    Sinha, D.N.; Olinger, C.T.

    1996-03-01

    This report reports on work performed for the International Atomic Energy Agency (IAEA) through the Program Office for Technical Assistance (POTAS). In this work, we investigate possible applications of nondestructive acoustics measurements to facilitate IAEA safeguards at bulk processing facilities. Two different acoustic techniques for verifying the internal structure of a processing tank were investigated. During this effort we also examined two acoustic techniques for assessing the fill level within a processing tank. The fill-level measurements could be made highly portable and have an added safeguards advantage that they can also detect stratification of fill material. This later application may be particularly useful in confirming the absence of stratification in plutonium processing tanks before accountability samples are withdrawn.

  3. Surface acoustic wave/silicon monolithic sensor/processor

    NASA Technical Reports Server (NTRS)

    Kowel, S. T.; Kornreich, P. G.; Nouhi, A.; Kilmer, R.; Fathimulla, M. A.; Mehter, E.

    1983-01-01

    A new technique for sputter deposition of piezoelectric zinc oxide (ZnO) is described. An argon-ion milling system was converted to sputter zinc oxide films in an oxygen atmosphere using a pure zinc oxide target. Piezoelectric films were grown on silicon dioxide and silicon dioxide overlayed with gold. The sputtered films were evaluated using surface acoustic wave measurements, X-ray diffraction, scanning electron microscopy, Auger electron spectroscopy, and resistivity measurements. The effect of the sputtering conditions on the film quality and the result of post-deposition annealing are discussed. The application of these films to the generation of surface acoustic waves is also discussed.

  4. Acoustically enhanced heat transport

    NASA Astrophysics Data System (ADS)

    Ang, Kar M.; Yeo, Leslie Y.; Friend, James R.; Hung, Yew Mun; Tan, Ming K.

    2016-01-01

    We investigate the enhancement of heat transfer in the nucleate boiling regime by inducing high frequency acoustic waves (f ˜ 106 Hz) on the heated surface. In the experiments, liquid droplets (deionized water) are dispensed directly onto a heated, vibrating substrate. At lower vibration amplitudes (ξs ˜ 10-9 m), the improved heat transfer is mainly due to the detachment of vapor bubbles from the heated surface and the induced thermal mixing. Upon increasing the vibration amplitude (ξs ˜ 10-8 m), the heat transfer becomes more substantial due to the rapid bursting of vapor bubbles happening at the liquid-air interface as a consequence of capillary waves travelling in the thin liquid film between the vapor bubble and the air. Further increases then lead to rapid atomization that continues to enhance the heat transfer. An acoustic wave displacement amplitude on the order of 10-8 m with 106 Hz order frequencies is observed to produce an improvement of up to 50% reduction in the surface temperature over the case without acoustic excitation.

  5. Acoustically enhanced heat transport

    SciTech Connect

    Ang, Kar M.; Hung, Yew Mun; Tan, Ming K.; Yeo, Leslie Y.

    2016-01-15

    We investigate the enhancement of heat transfer in the nucleate boiling regime by inducing high frequency acoustic waves (f ∼ 10{sup 6} Hz) on the heated surface. In the experiments, liquid droplets (deionized water) are dispensed directly onto a heated, vibrating substrate. At lower vibration amplitudes (ξ{sub s} ∼ 10{sup −9} m), the improved heat transfer is mainly due to the detachment of vapor bubbles from the heated surface and the induced thermal mixing. Upon increasing the vibration amplitude (ξ{sub s} ∼ 10{sup −8} m), the heat transfer becomes more substantial due to the rapid bursting of vapor bubbles happening at the liquid-air interface as a consequence of capillary waves travelling in the thin liquid film between the vapor bubble and the air. Further increases then lead to rapid atomization that continues to enhance the heat transfer. An acoustic wave displacement amplitude on the order of 10{sup −8} m with 10{sup 6} Hz order frequencies is observed to produce an improvement of up to 50% reduction in the surface temperature over the case without acoustic excitation.

  6. Acoustically enhanced heat transport.

    PubMed

    Ang, Kar M; Yeo, Leslie Y; Friend, James R; Hung, Yew Mun; Tan, Ming K

    2016-01-01

    We investigate the enhancement of heat transfer in the nucleate boiling regime by inducing high frequency acoustic waves (f ∼ 10(6) Hz) on the heated surface. In the experiments, liquid droplets (deionized water) are dispensed directly onto a heated, vibrating substrate. At lower vibration amplitudes (ξs ∼ 10(-9) m), the improved heat transfer is mainly due to the detachment of vapor bubbles from the heated surface and the induced thermal mixing. Upon increasing the vibration amplitude (ξs ∼ 10(-8) m), the heat transfer becomes more substantial due to the rapid bursting of vapor bubbles happening at the liquid-air interface as a consequence of capillary waves travelling in the thin liquid film between the vapor bubble and the air. Further increases then lead to rapid atomization that continues to enhance the heat transfer. An acoustic wave displacement amplitude on the order of 10(-8) m with 10(6) Hz order frequencies is observed to produce an improvement of up to 50% reduction in the surface temperature over the case without acoustic excitation.

  7. Acoustofluidics 14: Applications of acoustic streaming in microfluidic devices.

    PubMed

    Wiklund, Martin; Green, Roy; Ohlin, Mathias

    2012-07-21

    In part 14 of the tutorial series "Acoustofluidics--exploiting ultrasonic standing wave forces and acoustic streaming in microfluidic systems for cell and particle manipulation", we provide a qualitative description of acoustic streaming and review its applications in lab-on-a-chip devices. The paper covers boundary layer driven streaming, including Schlichting and Rayleigh streaming, Eckart streaming in the bulk fluid, cavitation microstreaming and surface-acoustic-wave-driven streaming.

  8. Sediment Acoustics: Wideband Model, Reflection Loss and Ambient Noise Inversion

    DTIC Science & Technology

    2011-09-01

    grain contact in water- saturated sand," J. Acoust. Soc. Am., vol. 124, pp. EL296-301, (2008). N. P. Chotiros, and M. J. Isakson. "Shear and...34Frame bulk modulus of porous granular marine sediments," J. Acoust. Soc. Am. 120, 699-710, (2006). B. J. Kraft and C. P. de Moustier, "Detailed

  9. c-axis inclined ZnO films for shear-wave transducers deposited by reactive sputtering using an additional blind

    SciTech Connect

    Link, M.; Schreiter, M.; Weber, J.; Gabl, R.; Pitzer, D.; Primig, R.; Wersing, W.; Assouar, M.B.; Elmazria, O.

    2006-03-15

    This article reports on the growth and characterization of polycrystalline ZnO films having c axis inclined up to 16 deg. with respect to the substrate normal. These films allow the excitation of shear and longitudinal waves with comparable electromechanical coupling constants and are of significant interest for thin film bulk acoustic resonators (FBARs). The films are deposited on silicon substrates covered by Al{sub 2}O{sub 3} and SiO{sub 2} buffer layers under low pressure using a modified reactive dc-pulsed magnetron sputtering system. A blind has been positioned between target and substrate, allowing oblique particle incidence without tilting the wafer. The study of structural properties of the deposited ZnO films by x-ray diffraction and scanning electron microscopy has permitted to show the presence of the inclined structure. Electromechanical coupling constants K up to 13% have been extracted for shear-mode excitation using highly overmoded FBARs.

  10. The acoustic spectrophonometer: a novel bioanalytical technique based on multifrequency acoustic devices.

    PubMed

    Stevenson, A C; Araya-Kleinsteuber, B; Sethi, R S; Mehta, H M; Lowe, C R

    2003-10-01

    A measurement technique similar to optical absorption spectroscopy but based on evanescent acoustic waves is described in this paper. This format employs a planar spiral coil to vibrate a single crystal of quartz from 6 to 400 MHz, in order to measure multifrequency acoustic spectra. Consistency with the defined Sauerbrey and Kanazawa terms K1 and K2 when applied to multiple frequencies was found for these specific operating conditions in terms of a significant fit between the measured and calculated values: For an IgG surface density of 13.5 ng mm(-2) the measured value of K1 is 22.5 x 10(-6) and the calculated value is 20.4 x 10(-6), whilst for glycerol viscous loadings of 5.131 cP the measured value of K2 is 0.47 and the calculated value is 0.54. Thus for these specific surface loadings the multifrequency data fits to the predictions of the Sauerbrey model to within 10% and to Kanazawa model within 13%. However collective frequency shifts for 5.131 cP solutions of sucrose, dextran and glucose were found to exhibit an unanticipated additional variability (R2 < 0.4) with frequency, but retained a square root of frequency dependency within a factor 2 of the interpolated K2 values. The response to the 5.131 cP dextran solution was found to be significantly below the other isoviscous solutions, with a substantially reduced frequency shift and K2 value than would be expected from its bulk viscosity. In comparison with these viscous solutions, IgG protein films consistently produced linear frequency shifts with little scatter (R2 > 0.96) that were proportional to the operating frequency, and fully consistent with the Sauerbrey model under these specific conditions. A t-test value of 14.52 was calculated from the variance and mean of the two groups, and demonstrates that the acoustic spectrophonometer can be used to distinguish between the acoustic impedance characteristics of two chemical systems that are not clearly differentiable at a single operating frequency.

  11. Nonlinear Acoustics

    DTIC Science & Technology

    1974-02-14

    Wester- velt. [60] Streaming. In 1831, Michael Faraday [61] noted that currents of air were set up in the neighborhood of vibrating plates-the first... ducei in the case of a paramettc amy (from Berktay an Leahy 141). C’ "". k•, SEC 10.1 NONLINEAR ACOUSTICS 345 The principal results of their analysis

  12. Acoustically based fetal heart rate monitor

    NASA Technical Reports Server (NTRS)

    Baker, Donald A.; Zuckerwar, Allan J.

    1991-01-01

    The acoustically based fetal heart rate monitor permits an expectant mother to perform the fetal Non-Stress Test in her home. The potential market would include the one million U.S. pregnancies per year requiring this type of prenatal surveillance. The monitor uses polyvinylidene fluoride (PVF2) piezoelectric polymer film for the acoustic sensors, which are mounted in a seven-element array on a cummerbund. Evaluation of the sensor ouput signals utilizes a digital signal processor, which performs a linear prediction routine in real time. Clinical tests reveal that the acoustically based monitor provides Non-Stress Test records which are comparable to those obtained with a commercial ultrasonic transducer.

  13. Writing magnetic patterns with surface acoustic waves

    SciTech Connect

    Li, Weiyang; Buford, Benjamin; Jander, Albrecht; Dhagat, Pallavi

    2014-05-07

    A novel patterning technique that creates magnetization patterns in a continuous magnetostrictive film with surface acoustic waves is demonstrated. Patterns of 10 μm wide stripes of alternating magnetization and a 3 μm dot of reversed magnetization are written using standing and focusing acoustic waves, respectively. The magnetization pattern is size-tunable, erasable, and rewritable by changing the magnetic field and acoustic power. This versatility, along with its solid-state implementation (no moving parts) and electronic control, renders it as a promising technique for application in magnetic recording, magnonic signal processing, magnetic particle manipulation, and spatial magneto-optical modulation.

  14. Acoustic transducer for acoustic microscopy

    DOEpatents

    Khuri-Yakub, Butrus T.; Chou, Ching H.

    1990-01-01

    A shear acoustic transducer-lens system in which a shear polarized piezoelectric material excites shear polarized waves at one end of a buffer rod having a lens at the other end which excites longitudinal waves in a coupling medium by mode conversion at selected locations on the lens.

  15. Acoustic transducer for acoustic microscopy

    DOEpatents

    Khuri-Yakub, B.T.; Chou, C.H.

    1990-03-20

    A shear acoustic transducer-lens system is described in which a shear polarized piezoelectric material excites shear polarized waves at one end of a buffer rod having a lens at the other end which excites longitudinal waves in a coupling medium by mode conversion at selected locations on the lens. 9 figs.

  16. Large area bulk superconductors

    DOEpatents

    Miller, Dean J.; Field, Michael B.

    2002-01-01

    A bulk superconductor having a thickness of not less than about 100 microns is carried by a polycrystalline textured substrate having misorientation angles at the surface thereof not greater than about 15.degree.; the bulk superconductor may have a thickness of not less than about 100 microns and a surface area of not less than about 50 cm.sup.2. The textured substrate may have a thickness not less than about 10 microns and misorientation angles at the surface thereof not greater than about 15.degree.. Also disclosed is a process of manufacturing the bulk superconductor and the polycrystalline biaxially textured substrate material.

  17. Acoustic chaos

    SciTech Connect

    Lauterborn, W.; Parlitz, U.; Holzfuss, J.; Billo, A.; Akhatov, I.

    1996-06-01

    Acoustic cavitation, a complex, spatio-temporal dynamical system, is investigated with respect to its chaotic properties. The sound output, the {open_quote}{open_quote}noise{close_quote}{close_quote}, is subjected to time series analysis. The spatial dynamics of the bubble filaments is captured by high speed holographic cinematography and subsequent digital picture processing from the holograms. Theoretical models are put forward for describing the pattern formation. {copyright} {ital 1996 American Institute of Physics.}

  18. Medical Acoustics

    NASA Astrophysics Data System (ADS)

    Beach, Kirk W.; Dunmire, Barbrina

    Medical acoustics can be subdivided into diagnostics and therapy. Diagnostics are further separated into auditory and ultrasonic methods, and both employ low amplitudes. Therapy (excluding medical advice) uses ultrasound for heating, cooking, permeablizing, activating and fracturing tissues and structures within the body, usually at much higher amplitudes than in diagnostics. Because ultrasound is a wave, linear wave physics are generally applicable, but recently nonlinear effects have become more important, even in low-intensity diagnostic applications.

  19. An acoustic glucose sensor.

    PubMed

    Hu, Ruifen; Stevenson, Adrian C; Lowe, Christopher R

    2012-05-15

    In vivo glucose monitoring is required for tighter glycaemic control. This report describes a new approach to construct a miniature implantable device based on a magnetic acoustic resonance sensor (MARS). A ≈ 600-800 nm thick glucose-responsive poly(acrylamide-co-3-acrylamidophenylboronic acid) (poly(acrylamide-co-3-APB)) film was polymerised on the quartz disc (12 mm in diameter and 0.25 mm thick) of the MARS. The swelling/shrinking of the polymer film induced by the glucose binding to the phenylboronate caused changes in the resonance amplitude of the quartz disc in the MARS. A linear relationship between the response of the MARS and the glucose concentration in the range ≈ 0-15 mM was observed, with the optimum response of the MARS sensor being obtained when the polymer films contained ≈ 20 mol% 3-APB. The MARS glucose sensor also functioned under flow conditions (9 μl/min) with a response almost identical to the sensor under static or non-flow conditions. The results suggest that the MARS could offer a promising strategy for developing a small subcutaneously implanted continuous glucose monitor.

  20. Effects of annealing electrodeposited bismuth Telluride films

    NASA Technical Reports Server (NTRS)

    Snyder, J.; Stoltz, N. G.

    2002-01-01

    Thermoelectric thin films exhibit different qualities when compared with bulk materials. The goal however is to achieve thermoelectric properties of bulk materials from electrodeposited thin films. Thin films are produced by electrochemical deposition at room temperature. In order to optimize thermoelectric figure of merit proper carrierconcentration must be obtained.

  1. Acoustic dose and acoustic dose-rate.

    PubMed

    Duck, Francis

    2009-10-01

    Acoustic dose is defined as the energy deposited by absorption of an acoustic wave per unit mass of the medium supporting the wave. Expressions for acoustic dose and acoustic dose-rate are given for plane-wave conditions, including temporal and frequency dependencies of energy deposition. The relationship between the acoustic dose-rate and the resulting temperature increase is explored, as is the relationship between acoustic dose-rate and radiation force. Energy transfer from the wave to the medium by means of acoustic cavitation is considered, and an approach is proposed in principle that could allow cavitation to be included within the proposed definitions of acoustic dose and acoustic dose-rate.

  2. Selective inorganic thin films

    SciTech Connect

    Phillips, M.L.F.; Weisenbach, L.A.; Anderson, M.T.

    1995-05-01

    This project is developing inorganic thin films as membranes for gas separation applications, and as discriminating coatings for liquid-phase chemical sensors. Our goal is to synthesize these coatings with tailored porosity and surface chemistry on porous substrates and on acoustic and optical sensors. Molecular sieve films offer the possibility of performing separations involving hydrogen, air, and natural gas constituents at elevated temperatures with very high separation factors. We are focusing on improving permeability and molecular sieve properties of crystalline zeolitic membranes made by hydrothermally reacting layered multicomponent sol-gel films deposited on mesoporous substrates. We also used acoustic plate mode (APM) oscillator and surface plasmon resonance (SPR) sensor elements as substrates for sol-gel films, and have both used these modified sensors to determine physical properties of the films and have determined the sensitivity and selectivity of these sensors to aqueous chemical species.

  3. An acoustic emission study of plastic deformation in polycrystalline aluminium

    NASA Technical Reports Server (NTRS)

    Bill, R. C.; Frederick, J. R.; Felbeck, D. K.

    1979-01-01

    Acoustic emission experiments were performed on polycrystalline and single crystal 99.99% aluminum while undergoing tensile deformation. It was found that acoustic emission counts as a function of grain size showed a maximum value at a particular grain size. Furthermore, the slip area associated with this particular grain size corresponded to the threshold level of detectability of single dislocation slip events. The rate of decline in acoustic emission activity as grain size is increased beyond the peak value suggests that grain boundary associated dislocation sources are giving rise to the bulk of the detected acoustic emissions.

  4. Bulk viscosity effects on ultrasonic thermoacoustic instability

    NASA Astrophysics Data System (ADS)

    Lin, Jeffrey; Scalo, Carlo; Hesselink, Lambertus

    2016-11-01

    We have carried out unstructured fully-compressible Navier-Stokes simulations of a minimal-unit traveling-wave ultrasonic thermoacoustic device in looped configuration. The model comprises a thermoacoustic stack with 85% porosity and a tapered area change to suppress the fundamental standing-wave mode. A bulk viscosity model, which accounts for vibrational and rotational molecular relaxation effects, is derived and implemented via direct modification of the viscous stress tensor, τij ≡ 2 μSij +λ/2 μ ∂uk/∂xk δij , where the bulk viscosity is defined by μb ≡ λ +2/3 μ . The effective bulk viscosity coefficient accurately captures acoustic absorption from low to high ultrasonic frequencies and matches experimental wave attenuation rates across five decades. Using pressure-based similitude, the model was downscaled from total length L = 2 . 58 m to 0 . 0258 m, corresponding to the frequency range f = 242 - 24200 Hz, revealing the effects of bulk viscosity and direct modification of the thermodynamic pressure. Simulations are carried out to limit cycle and exhibit growth rates consistent with linear stability analyses, based on Rott's theory.

  5. Acoustic Tooth Cleaner

    NASA Technical Reports Server (NTRS)

    Heyman, J. S.

    1984-01-01

    Acoustically-energized water jet aids in plaque breakdown. Acoustic Wand includes acoustic transducer 1/4 wave plate, and tapered cone. Together elements energize solution of water containing mild abrasive injected into mouth to help prevent calculous buildup.

  6. Gigahertz scanning acoustic microscopy analysis of voids in Cu-Sn micro-connects

    NASA Astrophysics Data System (ADS)

    Ross, G.; Vuorinen, V.; Petzold, M.; Paulasto-Kröckel, M.; Brand, S.

    2017-01-01

    Gigahertz scanning acoustic microscopy (GHz-SAM) is applied to the characterization of bulk voids in the Cu-Sn material system, often used in micro-connects. An increased demand for the development of miniaturized interconnect technologies, such as micro-connects, means that fast characterization methods are required for the assessment and detection of reliability impacting defects. This study attempts to formulate an analytical technique aimed at detecting micro-structural defects in Cu-Sn micro-connects, such as micro-bumps for 1st level interconnects and solid-liquid interdiffusion bonds for nano- and microelectromechanical systems. To study the potential of the analytical method, a specific electroplating chemistry was used that increases the probability of defect formation in the electroplated Cu film. The chemistry is known under certain electroplating overpotentials to promote hydrogen bubble induced voids within the Cu. The samples containing voids were inspected by GHz-SAM with a highly focused acoustic lens operating at 1.12 GHz. To validate the results, GHz-SAM micrographs were compared with focused ion beam prepared cross-sections of the selected samples. Advances in acoustic transducer technology operating in the GHz frequency band allow for micron sized defect examination of materials with enhanced lateral resolution and sub-surface sensitivity.

  7. Sputtered SiO2 as low acoustic impedance material for Bragg mirror fabrication in BAW resonators.

    PubMed

    Olivares, Jimena; Wegmann, Enrique; Capilla, José; Iborra, Enrique; Clement, Marta; Vergara, Lucía; Aigner, Robert

    2010-01-01

    In this paper we describe the procedure to sputter low acoustic impedance SiO(2) films to be used as a low acoustic impedance layer in Bragg mirrors for BAW resonators. The composition and structure of the material are assessed through infrared absorption spectroscopy. The acoustic properties of the films (mass density and sound velocity) are assessed through X-ray reflectometry and picosecond acoustic spectroscopy. A second measurement of the sound velocity is achieved through the analysis of the longitudinal lambda/2 resonance that appears in these silicon oxide films when used as uppermost layer of an acoustic reflector placed under an AlN-based resonator.

  8. Acoustic Liner for Turbomachinery Applications

    NASA Technical Reports Server (NTRS)

    Huff, Dennis L.; Sutliff, Daniel L.; Jones, Michael G.; Hebsur, Mohan G.

    2010-01-01

    The purpose of this innovation is to reduce aircraft noise in the communities surrounding airports by significantly attenuating the noise generated by the turbomachinery, and enhancing safety by providing a containment barrier for a blade failure. Acoustic liners are used in today's turbofan engines to reduce noise. The amount of noise reduction from an acoustic liner is a function of the treatment area, the liner design, and the material properties, and limited by the constraints of the nacelle or casement design. It is desirable to increase the effective area of the acoustic treatment to increase noise suppression. Modern turbofan engines use wide-chord rotor blades, which means there is considerable treatment area available over the rotor tip. Turbofan engines require containment over the rotors for protection from blade failure. Traditional methods use a material wrap such as Kevlar integrated with rub strips and sometimes metal layers (sandwiches). It is possible to substitute the soft rub-strip material with an open-cell metallic foam that provides noise-reduction benefits and a sacrificial material in the first layer of the containment system. An open-cell foam was evaluated that behaves like a bulk acoustic liner, serves as a tip rub strip, and can be integrated with a rotor containment system. Foams can be integrated with the fan-containment system to provide sufficient safety margins and increased noise attenuation. The major innovation is the integration of the foam with the containment.

  9. Wireless actuation of bulk acoustic modes in micromechanical resonators

    NASA Astrophysics Data System (ADS)

    Mateen, Farrukh; Brown, Benjamin; Erramilli, Shyamsunder; Mohanty, Pritiraj

    2016-08-01

    We report wireless actuation of a Lamb wave micromechanical resonator from a distance of over 1 m with an efficiency of over 15%. Wireless actuation of conventional micromechanical resonators can have broad impact in a number of applications from wireless communication and implantable biomedical devices to distributed sensor networks.

  10. Shallow Bulk Acoustic Wave (SBAW) Devices and Oscillators.

    DTIC Science & Technology

    1982-11-01

    millimeter adapter for the automatic network analyzer. The two phase-locked sources would be implemented as SBAW phase-locked oscillators at 7 GHz, followed ...GHz device was designed with the parameters shown in Fig. 4-18s to be replicated as devices using a Shipley resist on AT quartz, followed by ion milling...Width 0.4 um Aperture Width 100 x Number of Fingers/Transducer 1001 Center-to-Center Separation of Transducers 1000 1m Distance Between Transducers 200

  11. Material fabrication using acoustic radiation forces

    SciTech Connect

    Sinha, Naveen N.; Sinha, Dipen N.; Goddard, Gregory Russ

    2015-12-01

    Apparatus and methods for using acoustic radiation forces to order particles suspended in a host liquid are described. The particles may range in size from nanometers to millimeters, and may have any shape. The suspension is placed in an acoustic resonator cavity, and acoustical energy is supplied thereto using acoustic transducers. The resulting pattern may be fixed by using a solidifiable host liquid, forming thereby a solid material. Patterns may be quickly generated; typical times ranging from a few seconds to a few minutes. In a one-dimensional arrangement, parallel layers of particles are formed. With two and three dimensional transducer arrangements, more complex particle configurations are possible since different standing-wave patterns may be generated in the resonator. Fabrication of periodic structures, such as metamaterials, having periods tunable by varying the frequency of the acoustic waves, on surfaces or in bulk volume using acoustic radiation forces, provides great flexibility in the creation of new materials. Periodicities may range from millimeters to sub-micron distances, covering a large portion of the range for optical and acoustical metamaterials.

  12. A superior process for forming titanium hydrogen isotopic films

    NASA Technical Reports Server (NTRS)

    Steinberg, R.; Alger, D. L.; Cooper, D. W.

    1975-01-01

    Process forms stoichiometric, continuous, strongly bonded titanium hydrogen isotopic films. Films have thermal and electrical conductivities approximately the same as bulk pure titanium, ten times greater than those of usual thin films.

  13. Acoustic iridescence.

    PubMed

    Cox, Trevor J

    2011-03-01

    An investigation has been undertaken into acoustic iridescence, exploring how a device can be constructed which alter sound waves, in a similar way to structures in nature that act on light to produce optical iridescence. The main construction had many thin perforated sheets spaced half a wavelength apart for a specified design frequency. The sheets create the necessary impedance discontinuities to create backscattered waves, which then interfere to create strongly reflected sound at certain frequencies. Predictions and measurements show a set of harmonics, evenly spaced in frequency, for which sound is reflected strongly. And the frequency of these harmonics increases as the angle of observation gets larger, mimicking the iridescence seen in natural optical systems. Similar to optical systems, the reflections become weaker for oblique angles of reflection. A second construction was briefly examined which exploited a metamaterial made from elements and inclusions which were much smaller than the wavelength. Boundary element method predictions confirmed the potential for creating acoustic iridescence from layers of such a material.

  14. Acoustic transducer

    DOEpatents

    Drumheller, D.S.

    1997-12-30

    An acoustic transducer is described comprising a one-piece hollow mandrel into the outer surface of which is formed a recess with sides perpendicular to the central axis of the mandrel and separated by a first distance and with a bottom parallel to the central axis and within which recess are a plurality of washer-shaped discs of a piezoelectric material and at least one disc of a temperature-compensating material with the discs being captured between the sides of the recess in a pre-stressed interference fit, typically at 2,000 psi of compressive stress. The transducer also includes a power supply and means to connect to a measurement device. The transducer is intended to be used for telemetry between a measurement device located downhole in an oil or gas well and the surface. The transducer is of an construction that is stronger with fewer joints that could leak fluids into the recess holding the piezoelectric elements than is found in previous acoustic transducers. 4 figs.

  15. Acoustic transducer

    DOEpatents

    Drumheller, Douglas S.

    1997-01-01

    An acoustic transducer comprising a one-piece hollow mandrel into the outer surface of which is formed a recess with sides perpendicular to the central axis of the mandrel and separated by a first distance and with a bottom parallel to the central axis and within which recess are a plurality of washer-shaped discs of a piezoelectric material and at least one disc of a temperature-compensating material with the discs being captured between the sides of the recess in a pre-stressed interference fit, typically at 2000 psi of compressive stress. The transducer also includes a power supply and means to connect to a measurement device. The transducer is intended to be used for telemetry between a measurement device located downhole in an oil or gas well and the surface. The transducer is of an construction that is stronger with fewer joints that could leak fluids into the recess holding the piezoelectric elements than is found in previous acoustic transducers.

  16. Micromachined lead zirconium titanate thin-film-cantilever-based acoustic emission sensor with poly(N-isopropylacrylamide) actuator for increasing contact pressure

    NASA Astrophysics Data System (ADS)

    Feng, Guo-Hua; Chen, Wei-Ming

    2016-05-01

    This paper presents an innovative acousticemission (AE) sensor with a cantilever sensing structure. A hydrothermal lead zirconium titanate (PZT) film was deposited on the cantilever for AE sensing, and an SU8 micropillar at the free end of the cantilever served as an AE wave coupler; in addition, a poly(N-isopropylacrylamide)-based thermoresponsive actuator was integrated with the cantilever to increase the contact pressure exerted on the target. The AE sensor showed higher performance compared with an existing commercial AE sensor. Micromachining technology was used to fabricate AE sensors, and an array of four sensors was fabricated on a 50 μm thick titanium substrate of dimensions 15 mm × 15 mm. The piezoelectric properties of the hydrothermal PZT film were verified by electrically driving the cantilever and measuring the displacement; the piezoelectric constant d 31 of the cantilever was 2.43 pC N-1. The output force of the sensing cantilever generated by activating the thermoresponsive actuator was determined. For an electrical power input of 2.5 W, the maximum force output at the SU8 micropillar was 1 N. This force corresponded to the application of a pressure of 1.4 MPa on the target. Pencil lead break tests were conducted to determine and compare the performance of the proposed AE sensor with commercial sensors. Here, experimental and theoretical discussions on the effect of the activation of the thermoresponsive actuator of the proposed AE sensor on AE detection are presented.

  17. Arabic Phonology: An Acoustical and Physiological Investigation.

    ERIC Educational Resources Information Center

    Al-Ani, Salman H.

    This book presents an acoustical and physiological Investigation of contemporary standard Arabic as spoken in Iraq. Spectrograms and X-ray sound films are used to perform the analysis for the study. With this equipment, the author considers the vowels, consonants, pharyngealized consonants, pharyngeals and glottals, duration, gemination, and…

  18. Tunable acoustic double negativity metamaterial.

    PubMed

    Liang, Z; Willatzen, M; Li, J; Christensen, J

    2012-01-01

    Man-made composite materials called "metamaterials" allow for the creation of unusual wave propagation behavior. Acoustic and elastic metamaterials in particular, can pave the way for the full control of sound in realizing cloaks of invisibility, perfect lenses and much more. In this work we design acousto-elastic surface modes that are similar to surface plasmons in metals and on highly conducting surfaces perforated by holes. We combine a structure hosting these modes together with a gap material supporting negative modulus and collectively producing negative dispersion. By analytical techniques and full-wave simulations we attribute the observed behavior to the mass density and bulk modulus being simultaneously negative.

  19. Soap film vibration: origin of the dissipation.

    PubMed

    Acharige, Sébastien Kosgodagan; Elias, Florence; Derec, Caroline

    2014-11-07

    We investigate the complex dispersion relationship of a transverse antisymmetric wave on a horizontal soap film. Experimentally, the complex wave number k at a fixed forcing frequency is determined by measuring the vibrating amplitude of the soap film: the wavelength (linked to the real part of k) is determined by the spatial variation of the amplitude; the decay length (linked to the imaginary part of k) is determined by analyzing the resonance curves of the vibrating wave as a function of frequency. Theoretically, we compute the complex dispersion relationship taking into account the physical properties of the bulk liquid and gas phase, and of the gas-liquid interfaces. The comparison between the computation (developed to the leading order under our experimental conditions) and the experimental results confirms that the phase velocity is fixed by the interplay between surface tension, and liquid and air inertia, as reported in previous studies. Moreover, we show that the attenuation of the transverse antisymmetric wave originates from the viscous dissipation in the gas phase surrounding the liquid film. This result is an important step in understanding the propagation of an acoustic wave in liquid foam, using a bottom-up approach.

  20. MTCI acoustic agglomeration particulate control

    SciTech Connect

    Chandran, R.R.; Mansour, M.N.; Scaroni, A.W.; Koopmann, G.H.; Loth, J.L.

    1994-10-01

    The overall objective of this project is to demonstrate pulse combination induced acoustic enhancement of coal ash agglomeration and sulfur capture at conditions typical of direct coal-fired turbines and PFBC hot gas cleanup. MTCI has developed an advanced compact pulse combustor island for direct coal-firing in combustion gas turbines. This combustor island comprises a coal-fired pulse combustor, a combined ash agglomeration and sulfur capture chamber (CAASCC), and a hot cyclone. In the MTCI proprietary approach, the pulse combustion-induced high intensity sound waves improve sulfur capture efficiency and ash agglomeration. The resulting agglomerates allow the use of commercial cyclones and achieve very high particulate collection efficiency. In the MTCI proprietary approach, sorbent particles are injected into a gas stream subjected to an intense acoustic field. The acoustic field serves to improve sulfur capture efficiency by enhancing both gas film and intra-particle mass transfer rates. In addition, the sorbent particles act as dynamic filter foci, providing a high density of stagnant agglomerating centers for trapping the finer entrained (in the oscillating flow field) fly ash fractions. A team has been formed with MTCI as the prime contractor and Penn State University and West Virginia University as subcontractors to MTCI. MTCI is focusing on hardware development and system demonstration, PSU is investigating and modeling acoustic agglomeration and sulfur capture, and WVU is studying aerovalve fluid dynamics. Results are presented from all three studies.

  1. Acoustic cryocooler

    DOEpatents

    Swift, Gregory W.; Martin, Richard A.; Radenbaugh, Ray

    1990-01-01

    An acoustic cryocooler with no moving parts is formed from a thermoacoustic driver (TAD) driving a pulse tube refrigerator (PTR) through a standing wave tube. Thermoacoustic elements in the TAD are spaced apart a distance effective to accommodate the increased thermal penetration length arising from the relatively low TAD operating frequency in the range of 15-60 Hz. At these low operating frequencies, a long tube is required to support the standing wave. The tube may be coiled to reduce the overall length of the cryocooler. One or two PTR's are located on the standing wave tube adjacent antinodes in the standing wave to be driven by the standing wave pressure oscillations. It is predicted that a heat input of 1000 W at 1000 K will maintian a cooling load of 5 W at 80 K.

  2. Acoustic transducer

    DOEpatents

    Drumheller, Douglas S.

    2000-01-01

    An active acoustic transducer tool for use down-hole applications. The tool includes a single cylindrical mandrel including a shoulder defining the boundary of a narrowed portion over which is placed a sandwich-style piezoelectric tranducer assembly. The piezoelectric transducer assembly is prestressed by being placed in a thermal interference fit between the shoulder of the mandrel and the base of an anvil which is likewise positioned over the narrower portion of the mandrel. In the preferred embodiment, assembly of the tool is accomplished using a hydraulic jack to stretch the mandrel prior to emplacement of the cylindrical sandwich-style piezoelectric transducer assembly and anvil. After those elements are positioned and secured, the stretched mandrel is allowed to return substantially to its original (pre-stretch) dimensions with the result that the piezoelectric transducer elements are compressed between the anvil and the shoulder of the mandrel.

  3. Acoustic telemetry.

    SciTech Connect

    Drumheller, Douglas Schaeffer; Kuszmaul, Scott S.

    2003-08-01

    Broadcasting messages through the earth is a daunting task. Indeed, broadcasting a normal telephone conversion through the earth by wireless means is impossible with todays technology. Most of us don't care, but some do. Industries that drill into the earth need wireless communication to broadcast navigation parameters. This allows them to steer their drill bits. They also need information about the natural formation that they are drilling. Measurements of parameters such as pressure, temperature, and gamma radiation levels can tell them if they have found a valuable resource such as a geothermal reservoir or a stratum bearing natural gas. Wireless communication methods are available to the drilling industry. Information is broadcast via either pressure waves in the drilling fluid or electromagnetic waves in the earth and well tubing. Data transmission can only travel one way at rates around a few baud. Given that normal Internet telephone modems operate near 20,000 baud, these data rates are truly very slow. Moreover, communication is often interrupted or permanently blocked by drilling conditions or natural formation properties. Here we describe a tool that communicates with stress waves traveling through the steel drill pipe and production tubing in the well. It's based on an old idea called Acoustic Telemetry. But what we present here is more than an idea. This tool exists, it's drilled several wells, and it works. Currently, it's the first and only acoustic telemetry tool that can withstand the drilling environment. It broadcasts one way over a limited range at much faster rates than existing methods, but we also know how build a system that can communicate both up and down wells of indefinite length.

  4. Magnetic resonance imaging of acoustic streaming: absorption coefficient and acoustic field shape estimation.

    PubMed

    Madelin, Guillaume; Grucker, Daniel; Franconi, Jean-Michel; Thiaudiere, Eric

    2006-07-01

    In this study, magnetic resonance imaging (MRI) is used to visualize acoustic streaming in liquids. A single-shot spin echo sequence (HASTE) with a saturation band perpendicular to the acoustic beam permits the acquisition of an instantaneous image of the flow due to the application of ultrasound. An average acoustic streaming velocity can be estimated from the MR images, from which the ultrasonic absorption coefficient and the bulk viscosity of different glycerol-water mixtures can be deduced. In the same way, this MRI method could be used to assess the acoustic field and time-average power of ultrasonic transducers in water (or other liquids with known physical properties), after calibration of a geometrical parameter that is dependent on the experimental setup.

  5. Intelligent front-end sample preparation tool using acoustic streaming.

    SciTech Connect

    Cooley, Erika J.; McClain, Jaime L.; Murton, Jaclyn K.; Edwards, Thayne L.; Achyuthan, Komandoor E.; Branch, Darren W.; Clem, Paul Gilbert; Anderson, John Mueller; James, Conrad D.; Smith, Gennifer; Kotulski, Joseph Daniel

    2009-09-01

    We have successfully developed a nucleic acid extraction system based on a microacoustic lysis array coupled to an integrated nucleic acid extraction system all on a single cartridge. The microacoustic lysing array is based on 36{sup o} Y cut lithium niobate, which couples bulk acoustic waves (BAW) into the microchannels. The microchannels were fabricated using Mylar laminates and fused silica to form acoustic-fluidic interface cartridges. The transducer array consists of four active elements directed for cell lysis and one optional BAW element for mixing on the cartridge. The lysis system was modeled using one dimensional (1D) transmission line and two dimensional (2D) FEM models. For input powers required to lyse cells, the flow rate dictated the temperature change across the lysing region. From the computational models, a flow rate of 10 {micro}L/min produced a temperature rise of 23.2 C and only 6.7 C when flowing at 60 {micro}L/min. The measured temperature changes were 5 C less than the model. The computational models also permitted optimization of the acoustic coupling to the microchannel region and revealed the potential impact of thermal effects if not controlled. Using E. coli, we achieved a lysing efficacy of 49.9 {+-} 29.92 % based on a cell viability assay with a 757.2 % increase in ATP release within 20 seconds of acoustic exposure. A bench-top lysing system required 15-20 minutes operating up to 58 Watts to achieve the same level of cell lysis. We demonstrate that active mixing on the cartridge was critical to maximize binding and release of nucleic acid to the magnetic beads. Using a sol-gel silica bead matrix filled microchannel the extraction efficacy was 40%. The cartridge based magnetic bead system had an extraction efficiency of 19.2%. For an electric field based method that used Nafion films, a nucleic acid extraction efficiency of 66.3 % was achieved at 6 volts DC. For the flow rates we tested (10-50 {micro}L/min), the nucleic acid extraction

  6. 16 CFR 501.1 - Camera film.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 1 2012-01-01 2012-01-01 false Camera film. 501.1 Section 501.1 Commercial... 500 § 501.1 Camera film. Camera film packaged and labeled for retail sale is exempt from the net... should be expressed, provided: (a) The net quantity of contents on packages of movie film and bulk...

  7. 16 CFR 501.1 - Camera film.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Camera film. 501.1 Section 501.1 Commercial... 500 § 501.1 Camera film. Camera film packaged and labeled for retail sale is exempt from the net... should be expressed, provided: (a) The net quantity of contents on packages of movie film and bulk...

  8. 16 CFR 501.1 - Camera film.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Camera film. 501.1 Section 501.1 Commercial... 500 § 501.1 Camera film. Camera film packaged and labeled for retail sale is exempt from the net... should be expressed, provided: (a) The net quantity of contents on packages of movie film and bulk...

  9. 16 CFR 501.1 - Camera film.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 1 2011-01-01 2011-01-01 false Camera film. 501.1 Section 501.1 Commercial... 500 § 501.1 Camera film. Camera film packaged and labeled for retail sale is exempt from the net... should be expressed, provided: (a) The net quantity of contents on packages of movie film and bulk...

  10. 16 CFR 501.1 - Camera film.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Camera film. 501.1 Section 501.1 Commercial... 500 § 501.1 Camera film. Camera film packaged and labeled for retail sale is exempt from the net... should be expressed, provided: (a) The net quantity of contents on packages of movie film and bulk...

  11. The effect of confinement on the crystalline microstructure of polymer: fullerene bulk heterojunctions

    SciTech Connect

    Ashraf, A.; Dissanayake, D. M. N. M.; Eisaman, M. D.

    2015-07-01

    We investigate the effect of confinement on the coherence length and the crystalline microstructure of the polymer component of polymer: fullerene bulk heterojunction thin films using grazing incidence wide angle x-ray scattering. We find that the polymer crystallite size decreases and the alignment of the molecules along the surface normal increases, as the thin-film thickness is reduced from 920nm to < 20nm and approaches the thin-film confinement regime. Furthermore, we find that the polymer crystallite size near the surface (air interface) is lower than the crystallite size in the bulk or the bottom (substrate interface) of bulk heterojunction films thicker than the confinement regime. Variation in polymer crystallite size can cause changes in charge carrier mobility and recombination rates, which in turn affect the performance of bulk heterojunction thin film devices such as photovoltaics and photodetectors

  12. The effect of confinement on the crystalline microstructure of polymer: fullerene bulk heterojunctions

    DOE PAGES

    Ashraf, A.; Dissanayake, D. M. N. M.; Eisaman, M. D.

    2015-07-01

    We investigate the effect of confinement on the coherence length and the crystalline microstructure of the polymer component of polymer: fullerene bulk heterojunction thin films using grazing incidence wide angle x-ray scattering. We find that the polymer crystallite size decreases and the alignment of the molecules along the surface normal increases, as the thin-film thickness is reduced from 920nm to < 20nm and approaches the thin-film confinement regime. Furthermore, we find that the polymer crystallite size near the surface (air interface) is lower than the crystallite size in the bulk or the bottom (substrate interface) of bulk heterojunction films thickermore » than the confinement regime. Variation in polymer crystallite size can cause changes in charge carrier mobility and recombination rates, which in turn affect the performance of bulk heterojunction thin film devices such as photovoltaics and photodetectors« less

  13. Post Test Evaluation of HSCT Nozzle Acoustic Liner Subcomponents Subjected to a Hot Acoustic Durability Test

    NASA Technical Reports Server (NTRS)

    Verrilli, Michael J.; Lee, Kuan

    2008-01-01

    The acoustic liner system designed for use in the High Speed Civil Transport (HSCT) was tested in a thermal-acoustic environment. Five ceramic matrix composite (CMC) acoustic tile configurations, five bulk acoustic absorbers, and one thermal protection system design were tested. The CMC acoustic tiles were subjected to two 2 3/4 hr ambient temperature acoustic exposures to measure their dynamic response. One exposure was conducted on the tiles alone and the second exposure included the tiles and the T-foam bulk absorber. The measured tile RMS strains were small. With or without the T-foam absorber, the dynamic strains were below strain levels that would cause damage during fatigue loading. After the ambient exposure, a 75-hr durability test of the entire acoustic liner system was conducted using a thermal-acoustic cycle that approximated the anticipated service cycle. Acoustic loads up to 139 dB/Hz and temperatures up to 1670 F (910 C) were employed during this 60 cycle test. During the durability test, the CMC tiles were exposed to temperatures up to 1780 F and a transient through thickness gradient up to 490 F. The TPS peak temperatures on the hot side of the panels ranged from 750 to 1000 F during the 60 cycles. The through thickness delta T ranged from 450 to 650 F, varying with TPS location and cycle number. No damage, such as cracks or chipping, was observed in the CMC tiles after completion of the testing. However, on tile warped during the durability test and was replaced after 43 or 60 cycles. No externally observed damage was found in this tile. No failure of the CMC fasteners occurred, but damage was observed. Cracks and missing material occurred, only in the fastener head region. No indication of damage was observed in the T-foam acoustic absorbers. The SiC foam acoustic absorber experienced damage after about 43 cycles. Cracking in the TPS occurred around the attachment holes and under a vent. In spite of the development of damage, the TPS maintained

  14. Acoustic properties of a porous glass (vycor) at hypersonic frequencies.

    PubMed

    Levelut, C; Pelous, J

    2007-10-17

    Brillouin scattering experiments have been performed from 5 to 1600 K in vycor, a porous silica glass. The acoustic velocity and attenuation at hypersonic frequencies are compared to those of bulk silica and others porous silica samples. The experimental evidence for the influence of porosity on the scattering by acoustic waves is compared to calculations. The correlation between internal friction and thermal conductivity at low temperature is discussed.

  15. Acoustic energy-driven fluid pump and method

    SciTech Connect

    Janus, Michael C.; Richards, George A.; Robey, Edward H.

    1997-12-01

    Bulk fluid motion is promoted in a gaseous fluid contained within a conduit system provided with a diffuser without the need for a mean pressure differential across the conduit system. The contacting of the gaseous fluid with unsteady energy at a selected frequency and pressure amplitude induces fluid flow through the conical diffuser. The unsteady energy can be provided by pulse combustors, thermoacoustic engines, or acoustic energy generators such as acoustic speakers.

  16. Acoustical properties of highly porous fibrous materials

    NASA Technical Reports Server (NTRS)

    Lambert, R. F.

    1979-01-01

    Highly porous, fibrous bulk sound absorbing materials are studied with a view toward understanding their acoustical properties and performance in a wide variety of applications including liners of flow ducts. The basis and criteria for decoupling of acoustic waves in the pores of the frame and compressional waves in the frame structure are established. The equations of motion are recast in a form that elucidates the coupling mechanisms. The normal incidence surface impedance and absorption coefficient of two types of Kevlar 29 and an open celled foam material are studied. Experimental values and theoretical results are brought into agreement when the structure factor is selected to provide a fit to the experimental data. A parametric procedure for achieving that fit is established. Both a bulk material quality factor and a high frequency impedance level are required to characterize the real and imaginary part of the surface impedance and absorption coefficient. A derivation of the concepts of equivalent density and dynamic resistance is presented.

  17. Acoustic source for generating an acoustic beam

    DOEpatents

    Vu, Cung Khac; Sinha, Dipen N.; Pantea, Cristian

    2016-05-31

    An acoustic source for generating an acoustic beam includes a housing; a plurality of spaced apart piezo-electric layers disposed within the housing; and a non-linear medium filling between the plurality of layers. Each of the plurality of piezoelectric layers is configured to generate an acoustic wave. The non-linear medium and the plurality of piezo-electric material layers have a matching impedance so as to enhance a transmission of the acoustic wave generated by each of plurality of layers through the remaining plurality of layers.

  18. Canonical Acoustics and Its Application to Surface Acoustic Wave on Acoustic Metamaterials

    NASA Astrophysics Data System (ADS)

    Shen, Jian Qi

    2016-08-01

    In a conventional formalism of acoustics, acoustic pressure p and velocity field u are used for characterizing acoustic waves propagating inside elastic/acoustic materials. We shall treat some fundamental problems relevant to acoustic wave propagation alternatively by using canonical acoustics (a more concise and compact formalism of acoustic dynamics), in which an acoustic scalar potential and an acoustic vector potential (Φ ,V), instead of the conventional acoustic field quantities such as acoustic pressure and velocity field (p,u) for characterizing acoustic waves, have been defined as the fundamental variables. The canonical formalism of the acoustic energy-momentum tensor is derived in terms of the acoustic potentials. Both the acoustic Hamiltonian density and the acoustic Lagrangian density have been defined, and based on this formulation, the acoustic wave quantization in a fluid is also developed. Such a formalism of acoustic potentials is employed to the problem of negative-mass-density assisted surface acoustic wave that is a highly localized surface bound state (an eigenstate of the acoustic wave equations). Since such a surface acoustic wave can be strongly confined to an interface between an acoustic metamaterial (e.g., fluid-solid composite structures with a negative dynamical mass density) and an ordinary material (with a positive mass density), it will give rise to an effect of acoustic field enhancement on the acoustic interface, and would have potential applications in acoustic device design for acoustic wave control.

  19. What Is an Acoustic Neuroma

    MedlinePlus

    ... ANAUSA.org Connect with us! What is an Acoustic Neuroma? Each heading slides to reveal information. Important ... Acoustic Neuroma Important Points To Know About an Acoustic Neuroma An acoustic neuroma, also called a vestibular ...

  20. Inverse Doppler Effects in Broadband Acoustic Metamaterials

    NASA Astrophysics Data System (ADS)

    Zhai, S. L.; Zhao, X. P.; Liu, S.; Shen, F. L.; Li, L. L.; Luo, C. R.

    2016-08-01

    The Doppler effect refers to the change in frequency of a wave source as a consequence of the relative motion between the source and an observer. Veselago theoretically predicted that materials with negative refractions can induce inverse Doppler effects. With the development of metamaterials, inverse Doppler effects have been extensively investigated. However, the ideal material parameters prescribed by these metamaterial design approaches are complex and also challenging to obtain experimentally. Here, we demonstrated a method of designing and experimentally characterising arbitrary broadband acoustic metamaterials. These omni-directional, double-negative, acoustic metamaterials are constructed with ‘flute-like’ acoustic meta-cluster sets with seven double meta-molecules; these metamaterials also overcome the limitations of broadband negative bulk modulus and mass density to provide a region of negative refraction and inverse Doppler effects. It was also shown that inverse Doppler effects can be detected in a flute, which has been popular for thousands of years in Asia and Europe.

  1. Inverse Doppler Effects in Broadband Acoustic Metamaterials.

    PubMed

    Zhai, S L; Zhao, X P; Liu, S; Shen, F L; Li, L L; Luo, C R

    2016-08-31

    The Doppler effect refers to the change in frequency of a wave source as a consequence of the relative motion between the source and an observer. Veselago theoretically predicted that materials with negative refractions can induce inverse Doppler effects. With the development of metamaterials, inverse Doppler effects have been extensively investigated. However, the ideal material parameters prescribed by these metamaterial design approaches are complex and also challenging to obtain experimentally. Here, we demonstrated a method of designing and experimentally characterising arbitrary broadband acoustic metamaterials. These omni-directional, double-negative, acoustic metamaterials are constructed with 'flute-like' acoustic meta-cluster sets with seven double meta-molecules; these metamaterials also overcome the limitations of broadband negative bulk modulus and mass density to provide a region of negative refraction and inverse Doppler effects. It was also shown that inverse Doppler effects can be detected in a flute, which has been popular for thousands of years in Asia and Europe.

  2. Envelope solitons of acoustic plate modes and surface waves.

    PubMed

    Mayer, Andreas P; Kovalev, Alexander S

    2003-06-01

    The problem of the existence of evelope solitons in elastic plates and at solid surfaces covered by an elastic film is revisited with special attention paid to nonlinear long-wave short-wave interactions. Using asymptotic expansions and multiple scales, conditions for the existence of envelope solitons are established and it is shown how their parameters can be expressed in terms of the elastic moduli and mass densities of the materials involved. In addition to homogeneous plates, weak periodic modulation of the plate's material parameters are also considered. In the case of wave propagation in an elastic plate, modulations of weakly nonlinear carrier waves are governed by a coupled system of partial differential equations consisting of evolution equations for the complex amplitude of the carrier wave (the nonlinear Schrödinger equation for envelope solitons and the Mills-Trullinger equations for gap solitons), and the wave equation for long-wavelength acoustic plate modes. In contrast to this situation, envelope solitons of surface acoustic waves in a layered structure are normally described by the nonlinear Schrödinger equation alone. However, at higher orders of the carrier wave amplitude, the envelope soliton is found to be accompanied by a quasistatic long-wavelength strain field, which may be localized at the surface with penetration depth into the substrate of the order of the inverse amplitude or which may radiate energy into the bulk. A new set of modulation equations is derived for the resonant case of the carrier wave's group velocity being equal to the phase velocity of long-wavelength Rayleigh waves of the uncoated substrate.

  3. Film tension of liquid nano-film from molecular modeling

    NASA Astrophysics Data System (ADS)

    Peng, Tiefeng; Yang, Siyuan; Xiang, Fan; Liang, Yunpei; Li, Qibin; Gao, Xuechao; Liu, Sanjun

    2017-02-01

    Due to its geometry simplicity, the forces of thin liquid film are widely investigated and equivalently employed to explore the phys-chemical properties and mechanical stability of many other surfaces or colloid ensembles. The surface tension of bulk liquid (σ∞) and film tension (γ) are the most important parameters. Considering the insufficiency of detailed interpretation of film tension under micro-scale circumstances, a method for film tension was proposed based on numerical modeling. Assuming surface tension at different slab thicknesses being identical to the surface tension of film, the surface tension and disjoining pressure were subsequently used to evaluate the film tension based on the derivation of film thermodynamics, and a decreasing tendency was discovered for low temperature regions. The influence of saline concentration on nano-films was also investigated, and the comparison of film tensions suggested that higher concentration yielded larger film tension, with stronger decreasing intensity as a function of film thickness. Meanwhile, at thick film range (15-20 nm), film tension of higher concentration film continued to decrease as thickness increase, however it arrived to constant value for that of lower concentration. Finally, it was found that the film tension was almost independent on the film curvature, but varied with the thickness. The approach is applicable to symmetric emulsion films containing surfactants and bi-layer lipid films.

  4. Numerical analysis of acoustic impedance microscope utilizing acoustic lens transducer to examine cultured cells.

    PubMed

    Gunawan, Agus Indra; Hozumi, Naohiro; Takahashi, Kenta; Yoshida, Sachiko; Saijo, Yoshifumi; Kobayashi, Kazuto; Yamamoto, Seiji

    2015-12-01

    A new technique is proposed for non-contact quantitative cell observation using focused ultrasonic waves. This technique interprets acoustic reflection intensity into the characteristic acoustic impedance of the biological cell. The cells are cultured on a plastic film substrate. A focused acoustic beam is transmitted through the substrate to its interface with the cell. A two-dimensional (2-D) reflection intensity profile is obtained by scanning the focal point along the interface. A reference substance is observed under the same conditions. These two reflections are compared and interpreted into the characteristic acoustic impedance of the cell based on a calibration curve that was created prior to the observation. To create the calibration curve, a numerical analysis of the sound field is performed using Fourier Transforms and is verified using several saline solutions. Because the cells are suspended by two plastic films, no contamination is introduced during the observation. In a practical observation, a sapphire lens transducer with a center frequency of 300 MHz was employed using ZnO thin film. The objects studied were co-cultured rat-derived glial (astrocyte) cells and glioma cells. The result was the clear observation of the internal structure of the cells. The acoustic impedance of the cells was spreading between 1.62 and 1.72 MNs/m(3). Cytoskeleton was indicated by high acoustic impedance. The introduction of cytochalasin-B led to a significant reduction in the acoustic impedance of the glioma cells; its effect on the glial cells was less significant. It is believed that this non-contact observation method will be useful for continuous cell inspections.

  5. Coupling liquids acoustic velocity effects on elastic metallic bioglass properties

    NASA Astrophysics Data System (ADS)

    Metiri, W.; Hadjoub, F.; Doghmane, A.; Hadjoub, Z.

    2009-11-01

    The effect of surface acoustic wave, SAW, velocities of coupling liquids on acoustical properties of several bulk metallic glasses, BMG, has been investigated using simulation program based on acoustic microscopy. Thus, we determined variations of critical angles at which the excitation of longitudinal mode, θL and Rayleigh mode, θR occurs as a function of wave velocities in different coupling liquids, Vliq. Linear relations of the form θi =ai0 +βiVliq were deduced. The importance of such formula, used with Snell's law, lies in the direct determination of SAW velocities and consequently mechanical properties of BMGs.

  6. Acoustic metamaterials: From local resonances to broad horizons.

    PubMed

    Ma, Guancong; Sheng, Ping

    2016-02-01

    Within a time span of 15 years, acoustic metamaterials have emerged from academic curiosity to become an active field driven by scientific discoveries and diverse application potentials. This review traces the development of acoustic metamaterials from the initial findings of mass density and bulk modulus frequency dispersions in locally resonant structures to the diverse functionalities afforded by the perspective of negative constitutive parameter values, and their implications for acoustic wave behaviors. We survey the more recent developments, which include compact phase manipulation structures, superabsorption, and actively controllable metamaterials as well as the new directions on acoustic wave transport in moving fluid, elastic, and mechanical metamaterials, graphene-inspired metamaterials, and structures whose characteristics are best delineated by non-Hermitian Hamiltonians. Many of the novel acoustic metamaterial structures have transcended the original definition of metamaterials as arising from the collective manifestations of constituent resonating units, but they continue to extend wave manipulation functionalities beyond those found in nature.

  7. Acoustic metamaterials: From local resonances to broad horizons

    PubMed Central

    Ma, Guancong; Sheng, Ping

    2016-01-01

    Within a time span of 15 years, acoustic metamaterials have emerged from academic curiosity to become an active field driven by scientific discoveries and diverse application potentials. This review traces the development of acoustic metamaterials from the initial findings of mass density and bulk modulus frequency dispersions in locally resonant structures to the diverse functionalities afforded by the perspective of negative constitutive parameter values, and their implications for acoustic wave behaviors. We survey the more recent developments, which include compact phase manipulation structures, superabsorption, and actively controllable metamaterials as well as the new directions on acoustic wave transport in moving fluid, elastic, and mechanical metamaterials, graphene-inspired metamaterials, and structures whose characteristics are best delineated by non-Hermitian Hamiltonians. Many of the novel acoustic metamaterial structures have transcended the original definition of metamaterials as arising from the collective manifestations of constituent resonating units, but they continue to extend wave manipulation functionalities beyond those found in nature. PMID:26933692

  8. Acoustically induced stark effect for excitons in intrinsic semiconductors.

    PubMed

    Ivanov, A L; Littlewood, P B

    2001-09-24

    A Stark effect for excitons parametrically driven by coherent acoustic phonons is proposed. Our scheme refers to a low-temperature intrinsic semiconductor or semiconductor nanostructure pumped by an acoustic wave (frequency band nu(ac) approximately equal to 1-40 GHz and intensity range I(ac) approximately equal to 10(-2)-10(2) W/cm(2)) and probed by low-intensity light. Tunable optical band gaps, which strongly change the spectral shape of the exciton line, are induced in the polariton spectrum by acoustic pumping. We develop an exactly solvable model of the acoustic Stark effect and apply our results to GaAs driven by bulk or surface acoustic waves.

  9. Growth study of nonpolar Zn{sub 1-x}Mg{sub x}O epitaxial films on a-plane bulk ZnO by plasma-assisted molecular beam epitaxy

    SciTech Connect

    Laumer, Bernhard; Schuster, Fabian; Stutzmann, Martin; Bergmaier, Andreas; Dollinger, Guenther; Vogel, Stephen; Gries, Katharina I.; Volz, Kerstin; Eickhoff, Martin

    2012-09-17

    Nonpolar Zn{sub 1-x}Mg{sub x}O epitaxial films were grown by plasma-assisted molecular beam epitaxy on a-plane ZnO substrates. A smooth surface morphology was accomplished under oxygen-rich growth conditions. The benefits of the use of ZnO substrates on the structural properties are reflected by a low-density of threading dislocations. Furthermore, no indications for the generation of basal plane stacking faults are found. The pseudomorphic growth on a-plane ZnO substrates efficiently locks the epitaxial Zn{sub 1-x}Mg{sub x}O films to the wurtzite structure up to x = 0.25. The Mg concentration is not constant and increases with larger thickness. The optical properties reflect the influence of alloy disorder.

  10. Symptoms of Acoustic Neuroma

    MedlinePlus

    ... Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask Yourself ... Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask Yourself ...

  11. NPL closes acoustics department

    NASA Astrophysics Data System (ADS)

    Extance, Andy

    2016-11-01

    The UK's National Physical Laboratory (NPL) has withdrawn funding for its acoustics, polymer and thermoelectrics groups, triggering concern among airborne acoustics specialists that the move could undermine the country's noise-management policies.

  12. Identifying the Acoustic Neuroma

    MedlinePlus

    ... Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask Yourself ... Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask Yourself ...

  13. Phonons in iron: from the bulk to an epitaxial monolayer.

    PubMed

    Stankov, S; Röhlsberger, R; Slezak, T; Sladecek, M; Sepiol, B; Vogl, G; Chumakov, A I; Rüffer, R; Spiridis, N; Łazewski, J; Parliński, K; Korecki, J

    2007-11-02

    The confinement of materials in low-dimensional structures has significant impact on propagating excitations like phonons. Using the isotope-specific 57Fe nuclear resonant vibrational spectroscopy we were able to determine elastic and thermodynamic properties of ultrathin Fe films on W(110). With decreasing thickness one observes a significant increase of the mean atomic displacement that goes along with an enhancement of vibrational modes at low energies as compared to the bulk. The analysis reveals that these deviations result from atomic vibrations of the single atomic layers at the two boundaries of the film, while the atoms inside the films vibrate almost bulklike.

  14. Acoustic emission frequency discrimination

    NASA Technical Reports Server (NTRS)

    Sugg, Frank E. (Inventor); Graham, Lloyd J. (Inventor)

    1988-01-01

    In acoustic emission nondestructive testing, broadband frequency noise is distinguished from narrow banded acoustic emission signals, since the latter are valid events indicative of structural flaws in the material being examined. This is accomplished by separating out those signals which contain frequency components both within and beyond (either above or below) the range of valid acoustic emission events. Application to acoustic emission monitoring during nondestructive bond verification and proof loading of undensified tiles on the Space Shuttle Orbiter is considered.

  15. Deep Water Ocean Acoustics

    DTIC Science & Technology

    2015-07-17

    under-ice scattering , bathymetric diffraction and the application of the ocean acoustic Parabolic Equation to infrasound. 2. Tasks a. Task 1...QSR-14C0172-Ocean Acoustics -063015 Figure 10. Estimated reflection coefficient as a function of frequency by taking the difference of downgoing and...OASIS, INC. 1 Report No. QSR-14C0172-Ocean Acoustics -063015 Quarterly Progress Report Technical and Financial Deep Water Ocean Acoustics

  16. Deep Water Ocean Acoustics

    DTIC Science & Technology

    2015-10-19

    OASIS, INC. 1 Report No. QSR-14C0172-Ocean Acoustics-093015 Quarterly Progress Report Technical and Financial Deep Water Ocean Acoustics...number. 1. REPORT DATE OCT 2015 2. REPORT TYPE 3. DATES COVERED 01-07-2015 to 30-09-2015 4. TITLE AND SUBTITLE Deep Water Ocean Acoustics...understanding of the impact of the ocean and seafloor environmental variability on deep- water (long-range) ocean acoustic propagation and to develop

  17. Shallow Water Acoustics Studies

    DTIC Science & Technology

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Shallow Water Acoustics Studies James F. Lynch MS #12...N00014-14-1-0040 http://acoustics.whoi.edu/sw06/ LONG TERM GOALS The long term goals of our shallow water acoustics work are to: 1) understand the...nature of low frequency (10-1500 Hz) acoustic propagation, scattering and noise in shallow water when strong oceanic variability is present in the

  18. Coding Acoustic Metasurfaces.

    PubMed

    Xie, Boyang; Tang, Kun; Cheng, Hua; Liu, Zhengyou; Chen, Shuqi; Tian, Jianguo

    2017-02-01

    Coding acoustic metasurfaces can combine simple logical bits to acquire sophisticated functions in wave control. The acoustic logical bits can achieve a phase difference of exactly π and a perfect match of the amplitudes for the transmitted waves. By programming the coding sequences, acoustic metasurfaces with various functions, including creating peculiar antenna patterns and waves focusing, have been demonstrated.

  19. Tutorial on architectural acoustics

    NASA Astrophysics Data System (ADS)

    Shaw, Neil; Talaske, Rick; Bistafa, Sylvio

    2002-11-01

    This tutorial is intended to provide an overview of current knowledge and practice in architectural acoustics. Topics covered will include basic concepts and history, acoustics of small rooms (small rooms for speech such as classrooms and meeting rooms, music studios, small critical listening spaces such as home theatres) and the acoustics of large rooms (larger assembly halls, auditoria, and performance halls).

  20. Bulk Site Reference Materials

    SciTech Connect

    Barich, J.J. III; Jones, R.R. Sr.

    1996-12-31

    The selection, manufacture and use of Bulk Site Reference Materials (BSRMs) at hazardous waste sites is discussed. BSRMs are useful in preparing stabilization/solidification (S/S) formulations for soils, ranking competing S/S processes, comparing S/S alternatives to other technologies, and in interpreting data from different test types. BSRMs are large volume samples that are representative of the physical and chemical characteristics of a site soil, and that contain contaminants at reasonably high levels. A successful BSRM is extremely homogeneous and well-characterized. While not representative of any point on the site, they contain the contaminants of the site in the matrices of the site. Design objectives for a BSRM are to produce a material that (1) maintains good fidelity to site matrices and contaminants, and (2) exhibits the lowest possible relative standard deviation.

  1. Bulk material handling system

    DOEpatents

    Kleysteuber, William K.; Mayercheck, William D.

    1979-01-01

    This disclosure relates to a bulk material handling system particularly adapted for underground mining and includes a monorail supported overhead and carrying a plurality of conveyors each having input and output end portions with the output end portion of a first of the conveyors positioned above an input end portion of a second of the conveyors, a device for imparting motion to the conveyors to move the material from the input end portions toward the output end portions thereof, a device for supporting at least one of the input and output end portions of the first and second conveyors from the monorail, and the supporting device including a plurality of trolleys rollingly supported by the monorail whereby the conveyors can be readily moved therealong.

  2. Explosive bulk charge

    DOEpatents

    Miller, Jacob Lee

    2015-04-21

    An explosive bulk charge, including: a first contact surface configured to be selectively disposed substantially adjacent to a structure or material; a second end surface configured to selectively receive a detonator; and a curvilinear side surface joining the first contact surface and the second end surface. The first contact surface, the second end surface, and the curvilinear side surface form a bi-truncated hemispherical structure. The first contact surface, the second end surface, and the curvilinear side surface are formed from an explosive material. Optionally, the first contact surface and the second end surface each have a substantially circular shape. Optionally, the first contact surface and the second end surface consist of planar structures that are aligned substantially parallel or slightly tilted with respect to one another. The curvilinear side surface has one of a smooth curved geometry, an elliptical geometry, and a parabolic geometry.

  3. Bulk muscles, loose cables

    PubMed Central

    Liyanage, Chamari R D G; Kodali, Venkata

    2014-01-01

    The accessibility and usage of body building supplements is on the rise with stronger internet marketing strategies by the industry. The dangers posed by the ingredients in them are underestimated. A healthy young man came to the emergency room with palpitations and feeling unwell. Initial history and clinical examination were non-contributory to find the cause. ECG showed atrial fibrillation. A detailed history for any over the counter or herbal medicine use confirmed that he was taking supplements to bulk muscle. One of the components in these supplements is yohimbine; the onset of symptoms coincided with the ingestion of this product and the patient is symptom free after stopping it. This report highlights the dangers to the public of consuming over the counter products with unknown ingredients and the consequential detrimental impact on health. PMID:25326558

  4. Creating bulk nanocrystalline metal.

    SciTech Connect

    Fredenburg, D. Anthony; Saldana, Christopher J.; Gill, David D.; Hall, Aaron Christopher; Roemer, Timothy John; Vogler, Tracy John; Yang, Pin

    2008-10-01

    Nanocrystalline and nanostructured materials offer unique microstructure-dependent properties that are superior to coarse-grained materials. These materials have been shown to have very high hardness, strength, and wear resistance. However, most current methods of producing nanostructured materials in weapons-relevant materials create powdered metal that must be consolidated into bulk form to be useful. Conventional consolidation methods are not appropriate due to the need to maintain the nanocrystalline structure. This research investigated new ways of creating nanocrystalline material, new methods of consolidating nanocrystalline material, and an analysis of these different methods of creation and consolidation to evaluate their applicability to mesoscale weapons applications where part features are often under 100 {micro}m wide and the material's microstructure must be very small to give homogeneous properties across the feature.

  5. Bulk amorphous materials

    SciTech Connect

    Schwarz, R.B.; Archuleta, J.I.; Sickafus, K.E.

    1998-12-01

    This is the final report for a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of this work was to develop the competency for the synthesis of novel bulk amorphous alloys. The authors researched their synthesis methods and alloy properties, including thermal stability, mechanical, and transport properties. The project also addressed the development of vanadium-spinel alloys for structural applications in hostile environments, the measurement of elastic constants and thermal expansion in single-crystal TiAl from 300 to 750 K, the measurement of elastic constants in gallium nitride, and a study of the shock-induced martensitic transformations in NiTi alloys.

  6. Chip scale mechanical spectrum analyzers based on high quality factor overmoded bulk acouslic wave resonators

    SciTech Connect

    Olsson, R. H., III

    2012-03-01

    The goal of this project was to develop high frequency quality factor (fQ) product acoustic resonators matched to a standard RF impedance of 50 {Omega} using overmoded bulk acoustic wave (BAW) resonators. These resonators are intended to serve as filters in a chip scale mechanical RF spectrum analyzer. Under this program different BAW resonator designs and materials were studied theoretically and experimentally. The effort resulted in a 3 GHz, 50 {Omega}, sapphire overmoded BAW with a fQ product of 8 x 10{sup 13}, among the highest values ever reported for an acoustic resonator.

  7. Bulk solitary waves in elastic solids

    NASA Astrophysics Data System (ADS)

    Samsonov, A. M.; Dreiden, G. V.; Semenova, I. V.; Shvartz, A. G.

    2015-10-01

    A short and object oriented conspectus of bulk solitary wave theory, numerical simulations and real experiments in condensed matter is given. Upon a brief description of the soliton history and development we focus on bulk solitary waves of strain, also known as waves of density and, sometimes, as elastic and/or acoustic solitons. We consider the problem of nonlinear bulk wave generation and detection in basic structural elements, rods, plates and shells, that are exhaustively studied and widely used in physics and engineering. However, it is mostly valid for linear elasticity, whereas dynamic nonlinear theory of these elements is still far from being completed. In order to show how the nonlinear waves can be used in various applications, we studied the solitary elastic wave propagation along lengthy wave guides, and remarkably small attenuation of elastic solitons was proven in physical experiments. Both theory and generation for strain soliton in a shell, however, remained unsolved problems until recently, and we consider in more details the nonlinear bulk wave propagation in a shell. We studied an axially symmetric deformation of an infinite nonlinearly elastic cylindrical shell without torsion. The problem for bulk longitudinal waves is shown to be reducible to the one equation, if a relation between transversal displacement and the longitudinal strain is found. It is found that both the 1+1D and even the 1+2D problems for long travelling waves in nonlinear solids can be reduced to the Weierstrass equation for elliptic functions, which provide the solitary wave solutions as appropriate limits. We show that the accuracy in the boundary conditions on free lateral surfaces is of crucial importance for solution, derive the only equation for longitudinal nonlinear strain wave and show, that the equation has, amongst others, a bidirectional solitary wave solution, which lead us to successful physical experiments. We observed first the compression solitary wave in the

  8. Acoustic Wave Filter Technology - A Review.

    PubMed

    Ruppel, Clemens

    2017-04-04

    Today, acoustic filters are the filter technology to meet the requirements with respect to performance dictated by the cellular phone standards and their form factor. Around 2 billion cellular phones are sold every year, and smart phones are of a very high percentage of approximately two thirds. Smart phones require a very high number of filter functions ranging from the low double-digit range up to almost triple digit numbers in the near future. In the frequency range up to 1 GHz surface acoustic wave (SAW) filters are almost exclusively employed, while in the higher frequency range bulk acoustic wave (BAW) and SAW filters are competing for their shares. Prerequisites for the success of acoustic filters were the availability of high quality substrates, advanced and highly reproducible fabrication technologies, optimum filter techniques, precise simulation software, and advanced design tools that allow the fast and efficient design according to customer specifications. The paper will try to focus on innovations leading to high volume applications of intermediate frequency (IF) and radio frequency (RF) acoustic filters, e.g., TV IF filters, IF filters for cellular phones, and SAW/BAW RF filters for the RF front-end of cellular phones.

  9. Gas sensing with surface acoustic wave devices

    NASA Astrophysics Data System (ADS)

    Martin, S. J.; Schweizer, K. S.; Ricco, A. J.; Zipperian, T. E.

    1985-03-01

    The use of a ZnO-on-Si surface acoustic wave (SAW) resonator as a gas sensor is discussed. In particular, the sensitivity of the device to organic vapors is examined. The planar nature of the SAW device, in which the acoustic energy is confined to within roughly one acoustic wavelength of the surface, makes the device extremely sensitive to surface perturbations. This characteristic has been exploited in the construction of SAW gas sensors in which the surface wave propagation characteristics are altered by species adsorbed from the ambient gas. The porous nature of the sputtered ZnO film, in conjunction with the microbalance capability of the SAW device, gives the sensor the ability to distinguish molecules on the basis of both size and mass.

  10. Thermopower of thin iron films

    NASA Astrophysics Data System (ADS)

    Schepis, Randy; Schröder, Klaus

    1992-02-01

    Thin iron films were prepared by evaporation in a high vacuum system (pressure in the 10 -5 MPa range). The thermopower was measured in situ near room temperature as a function of film thickness. Iron films with rather high resistivity values showed a strong thickness effect of the Seeback coefficient, S, with the difference between S (bulk) and S (film) reaching values of up to (19±3) μV/K for a sample 5 nm thick. The difference between S (bulk) and S (film) decreased with increasing d values. However, a sample with a resistance value of 50 μΩ cm at d = 5 n had an S value which differed by less than 3 μV/K from S (bulk).

  11. Characterization of bulk superconductors through EBSD methods

    NASA Astrophysics Data System (ADS)

    Koblischka, M. R.; Koblischka-Veneva, A.

    2003-10-01

    The application of electron backscatter diffraction (EBSD) technique to bulk high- Tc superconductors is presented and reviewed. Due to the ceramic nature and the complex crystallographic unit cells of the perovskite-type high- Tc superconductors, the EBSD analysis is not yet as common as it deserves. We have successfully performed EBSD analysis on a variety of high- Tc compounds and samples including polycrystalline YBCO (pure and doped by alkali metals), melt-textured YBCO, thin and thick films of YBCO; the “green phase” Y 2BaCuO 5, thin film and melt-textured NdBa 2Cu 3O x and Bi-2212 single crystals and tapes. It is shown that the surface preparation of the samples is crucial due to the small information depth (up to 100 nm) of the EBSD technique. High quality Kikuchi patterns are the requirement in order to enable the automated EBSD mapping, which yields phase distributions, individual grain orientations and the misorientation angle distribution. The results can be presented in form of mappings, as charts, and as pole figures. These informations are required for a better understanding of the growth mechanism(s) of bulk high- Tc superconductors intended for applications.

  12. Lattice dynamics in elemental modulated Sb 2 Te 3 films: Lattice dynamics in elemental modulated Sb 2 Te 3 films

    DOE PAGES

    Bessas, D.; Winkler, M.; Sergueev, I.; ...

    2015-09-03

    We investigate the crystallinity and the lattice dynamics in elemental modulated Sbinline imageTeinline image films microscopically using high energy synchrotron radiation diffraction combined with inline imageSb nuclear inelastic scattering. The correlation length is found to be finite but less than 100 . Moreover, the element specific density of phonon states is extracted. A comparison with the element specific density of phonon states in bulk Sbinline imageTeinline image confirms that the main features in the density of phonon states arise from the layered structure. The average speed of sound at inline image inline image, is almost the same compared to bulkmore » Sbinline imageTeinline image at inline image, inline image. Similarly, the change in the acoustic cut-off energy is within the experimental detection limit. Therefore, we suggest that the lattice thermal conductivity in elemental modulated Sbinline imageTeinline image films should not be significantly changed from its bulk value.« less

  13. Indoor acoustic gain design

    NASA Astrophysics Data System (ADS)

    Concha-Abarca, Justo Andres

    2002-11-01

    The design of sound reinforcement systems includes many variables and usually some of these variables are discussed. There are criteria to optimize the performance of the sound reinforcement systems under indoor conditions. The equivalent acoustic distance, the necessary acoustic gain, and the potential acoustic gain are parameters which must be adjusted with respect to the loudspeaker array, electric power and directionality of loudspeakers, the room acoustics conditions, the distance and distribution of the audience, and the type of the original sources. The design and installation of front of the house and monitoring systems have individual criteria. This article is about this criteria and it proposes general considerations for the indoor acoustic gain design.

  14. Anisotropic Swirling Surface Acoustic Waves from Inverse Filtering for On-Chip Generation of Acoustic Vortices

    NASA Astrophysics Data System (ADS)

    Riaud, Antoine; Thomas, Jean-Louis; Charron, Eric; Bussonnière, Adrien; Bou Matar, Olivier; Baudoin, Michael

    2015-09-01

    From radio-electronics signal analysis to biological sample actuation, surface acoustic waves (SAWs) are involved in a multitude of modern devices. However, only the most simple standing or progressive waves such as plane and focused waves have been explored so far. In this paper, we expand the SAW toolbox with a wave family named "swirling surface acoustic waves" which are the 2D anisotropic analogue of bulk acoustic vortices. Similarly to their 3D counterpart, they appear as concentric structures of bright rings with a phase singularity in their center resulting in a central dark spot. After the rigorous mathematical definition of these waves, we synthesize them experimentally through the inverse filtering technique revisited for surface waves. For this purpose, we design a setup combining arrays of interdigitated transducers and a multichannel electronic that enables one to synthesize any prescribed wave field compatible with the anisotropy of the substrate in a region called the "acoustic scene." This work opens prospects for the design of integrated acoustic vortex generators for on-chip selective acoustic tweezing.

  15. Materials for Adaptive Structural Acoustic Controls

    DTIC Science & Technology

    1994-01-31

    Zirconate Titanate Stannate Films. J. Appl. Phys. 75, 1399 (1994). 52. Sheen, J., R. Guo, A. S. Bhalla, and L. E. Cross. Measurements of Dielectric...use of acoustic emission and concurrent current pulse measurement to separate domain switching and micro-cracking which can occur in the poling...motion is described in Appendix 13. New measurements of nonlinearity in PZT and PLZT compositions are used to support the theoretical conclusions. Full

  16. Quantum ion-acoustic wave oscillations in metallic nanowires

    SciTech Connect

    Moradi, Afshin

    2015-05-15

    The low-frequency electrostatic waves in metallic nanowires are studied using the quantum hydrodynamic model, in which the electron and ion components of the system are regarded as a two-species quantum plasma system. The Poisson equation as well as appropriate quantum boundary conditions give the analytical expressions of dispersion relations of the surface and bulk quantum ion-acoustic wave oscillations.

  17. Temperature effect on acoustic plasmons

    NASA Astrophysics Data System (ADS)

    Silkin, V. M.; Nazarov, V. U.; Balassis, A.; Chernov, I. P.; Chulkov, E. V.

    2016-10-01

    The presence of several kinds of carriers at the Fermi surface results in interesting complex dielectric properties of the bulk Pd in the low-energy excitation range. A most spectacular manifestation of this is the presence of a collective electronic excitation characterized by a soundlike dispersion, termed acoustic plasmon (AP). Due to the characteristic dispersion reaching zero energy in the long-wavelength limit, the question of the thermal stability of the excitation spectrum arises. In this work we explore this problem investigating the thermal effect on the electronic excitation spectrum in this material, tracing how the AP properties vary with the temperature increase. The main effect consists in the gradual destruction of AP in the energy range corresponding to the temperature.

  18. AST Launch Vehicle Acoustics

    NASA Technical Reports Server (NTRS)

    Houston, Janice; Counter, D.; Giacomoni, D.

    2015-01-01

    The liftoff phase induces acoustic loading over a broad frequency range for a launch vehicle. These external acoustic environments are then used in the prediction of internal vibration responses of the vehicle and components which result in the qualification levels. Thus, predicting these liftoff acoustic (LOA) environments is critical to the design requirements of any launch vehicle. If there is a significant amount of uncertainty in the predictions or if acoustic mitigation options must be implemented, a subscale acoustic test is a feasible pre-launch test option to verify the LOA environments. The NASA Space Launch System (SLS) program initiated the Scale Model Acoustic Test (SMAT) to verify the predicted SLS LOA environments and to determine the acoustic reduction with an above deck water sound suppression system. The SMAT was conducted at Marshall Space Flight Center and the test article included a 5% scale SLS vehicle model, tower and Mobile Launcher. Acoustic and pressure data were measured by approximately 250 instruments. The SMAT liftoff acoustic results are presented, findings are discussed and a comparison is shown to the Ares I Scale Model Acoustic Test (ASMAT) results.

  19. Acoustic Translation of an Acoustically Levitated Sample

    NASA Technical Reports Server (NTRS)

    Barmatz, M. B.; Allen, J. L.

    1986-01-01

    Acoustic-levitation apparatus uses only one acoustic mode to move sample from one region of chamber to another. Sample heated and cooled quickly by translation between hot and cold regions of levitation chamber. Levitated sample is raised into furnace region by raising plunger. Frequency of sound produced by transducers adjusted by feedback system to maintain (102) resonant mode, which levitates sample midway between transducers and plunger regardless of plunger position.

  20. Mapping vibrational surface and bulk modes in a single nanocube

    NASA Astrophysics Data System (ADS)

    Lagos, Maureen J.; Trügler, Andreas; Hohenester, Ulrich; Batson, Philip E.

    2017-03-01

    Imaging of vibrational excitations in and near nanostructures is essential for developing low-loss infrared nanophotonics, controlling heat transport in thermal nanodevices, inventing new thermoelectric materials and understanding nanoscale energy transport. Spatially resolved electron energy loss spectroscopy has previously been used to image plasmonic behaviour in nanostructures in an electron microscope, but hitherto it has not been possible to map vibrational modes directly in a single nanostructure, limiting our understanding of phonon coupling with photons and plasmons. Here we present spatial mapping of optical and acoustic, bulk and surface vibrational modes in magnesium oxide nanocubes using an atom-wide electron beam. We find that the energy and the symmetry of the surface polariton phonon modes depend on the size of the nanocubes, and that they are localized to the surfaces of the nanocube. We also observe a limiting of bulk phonon scattering in the presence of surface phonon modes. Most phonon spectroscopies are selectively sensitive to either surface or bulk excitations; therefore, by demonstrating the excitation of both bulk and surface vibrational modes using a single probe, our work represents advances in the detection and visualization of spatially confined surface and bulk phonons in nanostructures.

  1. Mapping vibrational surface and bulk modes in a single nanocube.

    PubMed

    Lagos, Maureen J; Trügler, Andreas; Hohenester, Ulrich; Batson, Philip E

    2017-03-22

    Imaging of vibrational excitations in and near nanostructures is essential for developing low-loss infrared nanophotonics, controlling heat transport in thermal nanodevices, inventing new thermoelectric materials and understanding nanoscale energy transport. Spatially resolved electron energy loss spectroscopy has previously been used to image plasmonic behaviour in nanostructures in an electron microscope, but hitherto it has not been possible to map vibrational modes directly in a single nanostructure, limiting our understanding of phonon coupling with photons and plasmons. Here we present spatial mapping of optical and acoustic, bulk and surface vibrational modes in magnesium oxide nanocubes using an atom-wide electron beam. We find that the energy and the symmetry of the surface polariton phonon modes depend on the size of the nanocubes, and that they are localized to the surfaces of the nanocube. We also observe a limiting of bulk phonon scattering in the presence of surface phonon modes. Most phonon spectroscopies are selectively sensitive to either surface or bulk excitations; therefore, by demonstrating the excitation of both bulk and surface vibrational modes using a single probe, our work represents advances in the detection and visualization of spatially confined surface and bulk phonons in nanostructures.

  2. Nearfield Acoustical Holography

    NASA Astrophysics Data System (ADS)

    Hayek, Sabih I.

    Nearfield acoustical holography (NAH) is a method by which a set of acoustic pressure measurements at points located on a specific surface (called a hologram) can be used to image sources on vibrating surfaces on the acoustic field in three-dimensional space. NAH data are processed to take advantage of the evanescent wavefield to image sources that are separated less that one-eighth of a wavelength.

  3. Deep Water Acoustics

    DTIC Science & Technology

    2016-06-28

    Estimates of basin-wide sound speed ( temperature ) fields obtained by the combination of acoustic, altimetry, and other data types with ocean...of acoustic coherence at long ranges in the ocean. Estimates of basin-wide sound speed ( temperature ) fields obtained by the combination of acoustic...index.html Award Number N00014-13-1-0053 LONG-TERM GOALS The ultimate limitations to the performance of long-range sonar are due to ocean sound speed

  4. Acoustic Communications (ACOMMS) ATD

    DTIC Science & Technology

    2016-06-14

    Acoustic Communications (ACOMMS) ATD Tam Nguyen 2531 Jefferson Davis Hwy Arlington, VA 22242 phone: (703) 604-6013 ext 520 fax: (703) 604-6056...email: NguyenTL@navsea.navy.mil Award # N0001499PD30007 LONG-TERM GOALS The goal of the recently completed Acoustic Communications Advanced...Technology Demonstration program (ACOMMS ATD) was to demonstrate long range and moderate data rate underwater acoustic communications between a submarine

  5. Deep Water Ocean Acoustics

    DTIC Science & Technology

    2016-04-30

    OASIS, INC. 1 Report No. QSR-14C0172-Ocean Acoustics-043016 Quarterly Progress Report Technical and Financial Deep Water Ocean Acoustics...understanding of the impact of the ocean and seafloor environmental variability on deep- water (long-range) ocean acoustic propagation and to...improve our understanding. During the past few years, the physics effects studied have been three-dimensional propagation on global scales, deep water

  6. Mass sensitivity of layered shear-horizontal surface acoustic wave devices for sensing applications

    NASA Astrophysics Data System (ADS)

    Kalantar-Zadeh, Kourosh; Trinchi, Adrian; Wlodarski, Wojtek; Holland, Anthony; Galatsis, Kosmas

    2001-11-01

    Layered Surface Acoustic Wave (SAW) devices that allow the propagation of Love mode acoustic waves will be studied in this paper. In these devices, the substrate allows the propagation of Surface Skimming Bulks Waves (SSBWs). By depositing layers, that the speed of Shear Horizontal (SH) acoustic wave propagation is less than that of the substrate, the propagation mode transforms to Love mode. Love mode devices which will be studied in this paper, have SiO2 and ZnO acoustic guiding layers. As Love mode of propagation has no movement of particles component normal to the active sensor surface, they can be employed for the sensing applications in the liquid media.

  7. Acoustic dispersive prism

    NASA Astrophysics Data System (ADS)

    Esfahlani, Hussein; Karkar, Sami; Lissek, Herve; Mosig, Juan R.

    2016-01-01

    The optical dispersive prism is a well-studied element, which allows separating white light into its constituent spectral colors, and stands in nature as water droplets. In analogy to this definition, the acoustic dispersive prism should be an acoustic device with capability of splitting a broadband acoustic wave into its constituent Fourier components. However, due to the acoustical nature of materials as well as the design and fabrication difficulties, there is neither any natural acoustic counterpart of the optical prism, nor any artificial design reported so far exhibiting an equivalent acoustic behaviour. Here, based on exotic properties of the acoustic transmission-line metamaterials and exploiting unique physical behaviour of acoustic leaky-wave radiation, we report the first acoustic dispersive prism, effective within the audible frequency range 800 Hz–1300 Hz. The dispersive nature, and consequently the frequency-dependent refractive index of the metamaterial are exploited to split the sound waves towards different and frequency-dependent directions. Meanwhile, the leaky-wave nature of the structure facilitates the sound wave radiation into the ambient medium.

  8. Acoustic dispersive prism.

    PubMed

    Esfahlani, Hussein; Karkar, Sami; Lissek, Herve; Mosig, Juan R

    2016-01-07

    The optical dispersive prism is a well-studied element, which allows separating white light into its constituent spectral colors, and stands in nature as water droplets. In analogy to this definition, the acoustic dispersive prism should be an acoustic device with capability of splitting a broadband acoustic wave into its constituent Fourier components. However, due to the acoustical nature of materials as well as the design and fabrication difficulties, there is neither any natural acoustic counterpart of the optical prism, nor any artificial design reported so far exhibiting an equivalent acoustic behaviour. Here, based on exotic properties of the acoustic transmission-line metamaterials and exploiting unique physical behaviour of acoustic leaky-wave radiation, we report the first acoustic dispersive prism, effective within the audible frequency range 800 Hz-1300 Hz. The dispersive nature, and consequently the frequency-dependent refractive index of the metamaterial are exploited to split the sound waves towards different and frequency-dependent directions. Meanwhile, the leaky-wave nature of the structure facilitates the sound wave radiation into the ambient medium.

  9. 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.

  10. Acoustic dispersive prism

    PubMed Central

    Esfahlani, Hussein; Karkar, Sami; Lissek, Herve; Mosig, Juan R.

    2016-01-01

    The optical dispersive prism is a well-studied element, which allows separating white light into its constituent spectral colors, and stands in nature as water droplets. In analogy to this definition, the acoustic dispersive prism should be an acoustic device with capability of splitting a broadband acoustic wave into its constituent Fourier components. However, due to the acoustical nature of materials as well as the design and fabrication difficulties, there is neither any natural acoustic counterpart of the optical prism, nor any artificial design reported so far exhibiting an equivalent acoustic behaviour. Here, based on exotic properties of the acoustic transmission-line metamaterials and exploiting unique physical behaviour of acoustic leaky-wave radiation, we report the first acoustic dispersive prism, effective within the audible frequency range 800 Hz–1300 Hz. The dispersive nature, and consequently the frequency-dependent refractive index of the metamaterial are exploited to split the sound waves towards different and frequency-dependent directions. Meanwhile, the leaky-wave nature of the structure facilitates the sound wave radiation into the ambient medium. PMID:26739504

  11. Effects on film structure on mechanical and adhesion properties of latex films

    SciTech Connect

    Charmeau, J.Y.; Holl, Y.; Kientz, E.

    1995-12-31

    In order to investigate the effect of the particular structure of latex films on mechanical (stress-strain behavior) and adhesion (measured by peeling) properties, this work compares these characteristics for latex films and corresponding {open_quotes}solution films{close_quotes}. Solution films were obtained by dissolving the latex film in an appropriate solvent and forming a new film by evaporating the solvent. Four different systems were studied. It was shown that latex films have Young`s moduli systematically much higher than the corresponding solution films. This is due to the fact that the hydrophilic shells of the latex particles form a continuous phase in the latex film which increases the modulus thanks to polar interactions. However, adhesion energy for latex films is always smaller than for solution films. This is interpreted in terms of structure of the film-support interface and dissipative processes within the bulk of the films.

  12. Efficient organic photovoltaic cells with vertically ordered bulk heterojunctions.

    PubMed

    Yu, Bo; Wang, Haibo; Yan, Donghang

    2013-12-06

    Nanoscale morphology has been proved to be the key parameter deciding the exciton dissociation and charge transportation in bulk heterojunction (BHJ) solar cells. In this paper, we report a kind of small molecular organic photovoltaic cell (OPV) with a vertically ordered BHJ prepared by the weak epitaxial growth method. By this method, zinc phthalocyanine (ZnPc) can easily be formed into a highly ordered and continuous thin film and C60 is inclined to become dispersed crystalline grains in ZnPc film. Furthermore, we can control both the size and distribution density of C60 crystalline grains in ZnPc thin film without destroying the order of the ZnPc thin film. The OPVs with the vertically ordered BHJ show a high fill factor and a power conversion efficiency over 3% has been achieved.

  13. Nonlinear acoustics experimental characterization of microstructure evolution in Inconel 617

    SciTech Connect

    Yao, Xiaochu; Liu, Yang; Lissenden, Cliff J.

    2014-02-18

    Inconel 617 is a candidate material for the intermediate heat exchanger in a very high temperature reactor for the next generation nuclear power plant. This application will require the material to withstand fatigue-ratcheting interaction at temperatures up to 950°C. Therefore nondestructive evaluation and structural health monitoring are important capabilities. Acoustic nonlinearity (which is quantified in terms of a material parameter, the acoustic nonlinearity parameter, β) has been proven to be sensitive to microstructural changes in material. This research develops a robust experimental procedure to track the evolution of damage precursors in laboratory tested Inconel 617 specimens using ultrasonic bulk waves. The results from the acoustic non-linear tests are compared with stereoscope surface damage results. Therefore, the relationship between acoustic nonlinearity and microstructural evaluation can be clearly demonstrated for the specimens tested.

  14. Nonlinear acoustics experimental characterization of microstructure evolution in Inconel 617

    NASA Astrophysics Data System (ADS)

    Yao, Xiaochu; Liu, Yang; Lissenden, Cliff J.

    2014-02-01

    Inconel 617 is a candidate material for the intermediate heat exchanger in a very high temperature reactor for the next generation nuclear power plant. This application will require the material to withstand fatigue-ratcheting interaction at temperatures up to 950°C. Therefore nondestructive evaluation and structural health monitoring are important capabilities. Acoustic nonlinearity (which is quantified in terms of a material parameter, the acoustic nonlinearity parameter, β) has been proven to be sensitive to microstructural changes in material. This research develops a robust experimental procedure to track the evolution of damage precursors in laboratory tested Inconel 617 specimens using ultrasonic bulk waves. The results from the acoustic non-linear tests are compared with stereoscope surface damage results. Therefore, the relationship between acoustic nonlinearity and microstructural evaluation can be clearly demonstrated for the specimens tested.

  15. Thin films for material engineering

    NASA Astrophysics Data System (ADS)

    Wasa, Kiyotaka

    2016-07-01

    Thin films are defined as two-dimensional materials formed by condensing one by one atomic/molecular/ionic species of matter in contrast to bulk three-dimensional sintered ceramics. They are grown through atomic collisional chemical reaction on a substrate surface. Thin film growth processes are fascinating for developing innovative exotic materials. On the basis of my long research on sputtering deposition, this paper firstly describes the kinetic energy effect of sputtered adatoms on thin film growth and discusses on a possibility of room-temperature growth of cubic diamond crystallites and the perovskite thin films of binary compound PbTiO3. Secondly, high-performance sputtered ferroelectric thin films with extraordinary excellent crystallinity compatible with MBE deposited thin films are described in relation to a possible application for thin-film MEMS. Finally, the present thin-film technologies are discussed in terms of a future material science and engineering.

  16. Membrane-type Acoustic Metamaterials

    NASA Astrophysics Data System (ADS)

    Ma, Guancong

    Resonant-base membrane-type acoustic metamaterials (MAMs) are investigated with experiments and simulations. Three exotic phenomena, including negative effective mass density, negative effective bulk modulus, and total absorption are demonstrated. As a start, a single-membrane resonator, which consists of a tightened piece of elastic membrane with a relatively rigid weight attached to the center, is studied in detail. It is shown that due to the anti-resonance, such structure is capable of totally reflecting low-frequency airborne sound. With the help of the simulations, we further reveal that the anti-resonance results in extremely large effective mass density, further explaining the large transmission loss. By establishing coupling between two MAMs via a sealed section of air, we discovered that the system displays clear monopolar resonance. Consequently, negativity in effective bulk modulus is achieved. The third kind of MAM is intended to be a perfect absorber for low-frequency sound. The task is accomplished by using asymmetric rigid platelets. We show that the eigenmodes' displacement profiles have large curvatures around the platelets' perimeters, implying highly concentrated elastic bending energy. Also, the broken symmetry introduces rotational freedom into our MAM. Consequently, the eigenmodes' coupling to far-field radiation is effectively reduced, thereby giving rise to strong absorption.

  17. Extraordinary transmission of gigahertz surface acoustic waves

    PubMed Central

    Mezil, Sylvain; Chonan, Kazuki; Otsuka, Paul H.; Tomoda, Motonobu; Matsuda, Osamu; Lee, Sam H.; Wright, Oliver B.

    2016-01-01

    Extraordinary transmission of waves, i.e. a transmission superior to the amount predicted by geometrical considerations of the aperture alone, has to date only been studied in the bulk. Here we present a new class of extraordinary transmission for waves confined in two dimensions to a flat surface. By means of acoustic numerical simulations in the gigahertz range, corresponding to acoustic wavelengths λ ~ 3–50 μm, we track the transmission of plane surface acoustic wave fronts between two silicon blocks joined by a deeply subwavelength bridge of variable length with or without an attached cavity. Several resonant modes of the structure, both one- and two-dimensional in nature, lead to extraordinary acoustic transmission, in this case with transmission efficiencies, i.e. intensity enhancements, up to ~23 and ~8 in the two respective cases. We show how the cavity shape and bridge size influence the extraordinary transmission efficiency. Applications include new metamaterials and subwavelength imaging. PMID:27640998

  18. Organoboron polymers for photovoltaic bulk heterojunctions.

    PubMed

    Cataldo, Sebastiano; Fabiano, Simone; Ferrante, Francesco; Previti, Francesco; Patanè, Salvatore; Pignataro, Bruno

    2010-07-15

    We report on the application of three-coordinate organoboron polymers, inherently strong electron acceptors, in flexible photovoltaic (PV) cells. Poly[(1,4-divinylenephenylene)(2,4,6-triisopropylphenylborane)] (PDB) has been blended with poly(3-hexylthiophene-2,5-diyl) (P3HT) to form a thin film bulk heterojunction (BHJ) on PET/ITO substrates. Morphology may be modulated to give a high percentage of domains (10-20 nm in size) allowing exciton separation. The photoelectric properties of the BHJs in devices with aluminium back electrodes were imaged by light beam induced current (LBIC) and light beam induced voltage (LBIV) techniques. Open circuit voltages, short circuit currents and overall external quantum efficiencies obtained are among the highest reported for all-polymer PV cells.

  19. Coupled membranes with doubly negative mass density and bulk modulus.

    PubMed

    Yang, Min; Ma, Guancong; Yang, Zhiyu; Sheng, Ping

    2013-03-29

    We present a structurally and conceptually simple acoustic double negative metamaterial comprising two coupled membranes. Owing to its symmetry, the system can generate both monopolar and dipolar resonances that are separately tunable, thereby making broadband double negativity possible. A homogenization scheme is implemented that enables the exact characterization of our metamaterial by the effective mass density and bulk modulus even beyond the usual long-wavelength regime, with the measured displacement fields on the sample's surfaces as inputs. Double negativity is achieved in the frequency range of 520-830 Hz. Transmission and reflection predictions using effective parameters are shown to agree remarkably well with the experiment.

  20. Tailoring Magnetic Properties in Bulk Nanostructured Solids

    NASA Astrophysics Data System (ADS)

    Morales, Jason Rolando

    Important magnetic properties and behaviors such as coercivity, remanence, susceptibility, energy product, and exchange coupling can be tailored by controlling the grain size, composition, and density of bulk magnetic materials. At nanometric length scales the grain size plays an increasingly important role since magnetic domain behavior and grain boundary concentration determine bulk magnetic behavior. This has spurred a significant amount of work devoted to developing magnetic materials with nanometric features (thickness, grain/crystallite size, inclusions or shells) in 0D (powder), 1D (wires), and 2D (thin films) materials. Large 3D nanocrystalline materials are more suitable for many applications such as permanent magnets, magneto-optical Faraday isolators etc. Yet there are relatively few successful demonstrations of 3D magnetic materials with nanoscale influenced properties available in the literature. Making dense 3D bulk materials with magnetic nanocrystalline microstructures is a challenge because many traditional densification techniques (HIP, pressureless sintering, etc.) move the microstructure out of the "nano" regime during densification. This dissertation shows that the Current Activated Pressure Assisted Densification (CAPAD) method, also known as spark plasma sintering, can be used to create dense, bulk, magnetic, nanocrystalline solids with varied compositions suited to fit many applications. The results of my research will first show important implications for the use of CAPAD for the production of exchange-coupled nanocomposite magnets. Decreases in grain size were shown to have a significant role in increasing the magnitude of exchange bias. Second, preferentially ordered bulk magnetic materials were produced with highly anisotropic material properties. The ordered microstructure resulted in changing magnetic property magnitudes (ex. change in coercivity by almost 10x) depending on the relative orientation (0° vs. 90°) of an externally

  1. 49 CFR 178.519 - Standards for plastic film bags.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Standards for plastic film bags. 178.519 Section...-bulk Performance-Oriented Packaging Standards § 178.519 Standards for plastic film bags. (a) The identification code for a plastic film bag is 5H4. (b) Construction requirements for plastic film bags are...

  2. 49 CFR 178.519 - Standards for plastic film bags.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Standards for plastic film bags. 178.519 Section...-bulk Performance-Oriented Packaging Standards § 178.519 Standards for plastic film bags. (a) The identification code for a plastic film bag is 5H4. (b) Construction requirements for plastic film bags are...

  3. 49 CFR 178.519 - Standards for plastic film bags.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Standards for plastic film bags. 178.519 Section...-bulk Performance-Oriented Packaging Standards § 178.519 Standards for plastic film bags. (a) The identification code for a plastic film bag is 5H4. (b) Construction requirements for plastic film bags are...

  4. Thermoelastic response of thin metal films and their adjacent materials

    SciTech Connect

    Kang, S.; Yoon, Y.; Kim, J.; Kim, W.

    2013-01-14

    A pulsed laser beam applied to a thin metal film is capable of launching an acoustic wave due to thermal expansion. Heat transfer from the thin metal film to adjacent materials can also induce thermal expansion; thus, the properties of these adjacent materials (as well as the thin metal film) should be considered for a complete description of the thermoelastic response. Here, we show that adjacent materials with a small specific heat and large thermal expansion coefficient can generate an enhanced acoustic wave and we demonstrate a three-fold increase in the peak pressure of the generated acoustic wave on substitution of parylene for polydimethylsiloxane.

  5. Influence of blend microstructure on bulk heterojunction organic photovoltaic performance.

    PubMed

    Brabec, Christoph J; Heeney, Martin; McCulloch, Iain; Nelson, Jenny

    2011-03-01

    The performance of organic photovoltaic devices based upon bulk heterojunction blends of donor and acceptor materials has been shown to be highly dependent on the thin film microstructure. In this tutorial review, we discuss the factors responsible for influencing blend microstructure and how these affect device performance. In particular we discuss how various molecular design approaches can affect the thin film morphology of both the donor and acceptor components, as well as their blend microstructure. We further examine the influence of polymer molecular weight and blend composition upon device performance, and discuss how a variety of processing techniques can be used to control the blend microstructure, leading to improvements in solar cell efficiencies.

  6. The Acoustical Environment.

    ERIC Educational Resources Information Center

    Smith, Melissa

    Asserting that without an adequate acoustical environment, learning activities can be hindered, this paper reviews the literature on classroom acoustics, particularly noise, reverberation, signal-to-noise ratio, task performance, and recommendations for improvement. Through this review, the paper seeks to determine whether portable classrooms…

  7. Cystic acoustic schwannomas.

    PubMed

    Lunardi, P; Missori, P; Mastronardi, L; Fortuna, A

    1991-01-01

    Three cases with large space-occupying cysts in the cerebellopontine angle are reported. CT and MRI findings were not typical for acoustic schwannomas but at operation, besides the large cysts, small acoustic schwannomas could be detected and removed. The clinical and neuroradiological features of this unusual variety and the CT and MRI differential diagnosis of cerebellopontine angle lesions are discussed.

  8. Surface resistance measurement of modified QMG superconducting bulks

    NASA Astrophysics Data System (ADS)

    Saito, A.; Sekiya, N.; Teshima, H.; Obara, H.; Noguchi, Y.; Hirano, H.; Hirano, S.; Ohshima, S.

    2006-10-01

    We investigated the microwave properties of high-temperature superconductor (HTS) bulks for high-power microwave applications. The HTS bulk samples of Dy-Ba-Cu-O and Gd-Ba-Cu-O, were prepared using the modified quench and melt growth (QMG) process. The relationship among the bulk surface mirror polishing process, oxygen annealing process, and surface resistance (Rs) was also investigated. The Rs of the HTS bulks was measured using the dielectric resonator method at 21.8 GHz for the TE011 mode. The measurement temperature was varied from 20 to 95 K. We found that the annealing after surface mirror polishing was more effective to obtain low Rs than polishing after annealing. Although the Rs value of the optimized Dy-Ba-Cu-O bulk sample at 20 K was twofold larger than that of the high-quality YBa2Cu3O7-δ thin film fabricated by THEVA GmbH, the Rs value was even low enough to be used for microwave devices. These results indicate that Dy-Ba-Cu-O bulk superconductors are feasible for applications to high-power transmit filters for mobile communication systems.

  9. Acoustic Remote Sensing

    NASA Astrophysics Data System (ADS)

    Dowling, David R.; Sabra, Karim G.

    2015-01-01

    Acoustic waves carry information about their source and collect information about their environment as they propagate. This article reviews how these information-carrying and -collecting features of acoustic waves that travel through fluids can be exploited for remote sensing. In nearly all cases, modern acoustic remote sensing involves array-recorded sounds and array signal processing to recover multidimensional results. The application realm for acoustic remote sensing spans an impressive range of signal frequencies (10-2 to 107 Hz) and distances (10-2 to 107 m) and involves biomedical ultrasound imaging, nondestructive evaluation, oil and gas exploration, military systems, and Nuclear Test Ban Treaty monitoring. In the past two decades, approaches have been developed to robustly localize remote sources; remove noise and multipath distortion from recorded signals; and determine the acoustic characteristics of the environment through which the sound waves have traveled, even when the recorded sounds originate from uncooperative sources or are merely ambient noise.

  10. Acoustic suspension system

    NASA Technical Reports Server (NTRS)

    Lee, M. C.; Wang, T. G. (Inventor)

    1983-01-01

    An acoustic levitation system is described, with single acoustic source and a small reflector to stably levitate a small object while the object is processed as by coating or heating it. The system includes a concave acoustic source which has locations on opposite sides of its axis that vibrate towards and away from a focal point to generate a converging acoustic field. A small reflector is located near the focal point, and preferably slightly beyond it, to create an intense acoustic field that stably supports a small object near the reflector. The reflector is located about one-half wavelength from the focal point and is concavely curved to a radius of curvature (L) of about one-half the wavelength, to stably support an object one-quarter wavelength (N) from the reflector.

  11. Virtual acoustics displays

    NASA Technical Reports Server (NTRS)

    Wenzel, Elizabeth M.; Fisher, Scott S.; Stone, Philip K.; Foster, Scott H.

    1991-01-01

    The real time acoustic display capabilities are described which were developed for the Virtual Environment Workstation (VIEW) Project at NASA-Ames. The acoustic display is capable of generating localized acoustic cues in real time over headphones. An auditory symbology, a related collection of representational auditory 'objects' or 'icons', can be designed using ACE (Auditory Cue Editor), which links both discrete and continuously varying acoustic parameters with information or events in the display. During a given display scenario, the symbology can be dynamically coordinated in real time with 3-D visual objects, speech, and gestural displays. The types of displays feasible with the system range from simple warnings and alarms to the acoustic representation of multidimensional data or events.

  12. Cochlear bionic acoustic metamaterials

    NASA Astrophysics Data System (ADS)

    Ma, Fuyin; Wu, Jiu Hui; Huang, Meng; Fu, Gang; Bai, Changan

    2014-11-01

    A design of bionic acoustic metamaterial and acoustic functional devices was proposed by employing the mammalian cochlear as a prototype. First, combined with the experimental data in previous literatures, it is pointed out that the cochlear hair cells and stereocilia cluster are a kind of natural biological acoustic metamaterials with the negative stiffness characteristics. Then, to design the acoustic functional devices conveniently in engineering application, a simplified parametric helical structure was proposed to replace actual irregular cochlea for bionic design, and based on the computational results of such a bionic parametric helical structure, it is suggested that the overall cochlear is a local resonant system with the negative dynamic effective mass characteristics. There are many potential applications in the bandboard energy recovery device, cochlear implant, and acoustic black hole.

  13. Acoustic integrated extinction

    PubMed Central

    Norris, Andrew N.

    2015-01-01

    The integrated extinction (IE) is defined as the integral of the scattering cross section as a function of wavelength. Sohl et al. (2007 J. Acoust. Soc. Am. 122, 3206–3210. (doi:10.1121/1.2801546)) derived an IE expression for acoustic scattering that is causal, i.e. the scattered wavefront in the forward direction arrives later than the incident plane wave in the background medium. The IE formula was based on electromagnetic results, for which scattering is causal by default. Here, we derive a formula for the acoustic IE that is valid for causal and non-causal scattering. The general result is expressed as an integral of the time-dependent forward scattering function. The IE reduces to a finite integral for scatterers with zero long-wavelength monopole and dipole amplitudes. Implications for acoustic cloaking are discussed and a new metric is proposed for broadband acoustic transparency. PMID:27547100

  14. Direct Field Acoustic Testing

    NASA Technical Reports Server (NTRS)

    Larkin, Paul; Goldstein, Bob

    2008-01-01

    This paper presents an update to the methods and procedures used in Direct Field Acoustic Testing (DFAT). The paper will discuss some of the recent techniques and developments that are currently being used and the future publication of a reference standard. Acoustic testing using commercial sound system components is becoming a popular and cost effective way of generating a required acoustic test environment both in and out of a reverberant chamber. This paper will present the DFAT test method, the usual setup and procedure and the development and use of a closed-loop, narrow-band control system. Narrow-band control of the acoustic PSD allows all standard techniques and procedures currently used in random control to be applied to acoustics and some examples are given. The paper will conclude with a summary of the development of a standard practice guideline that is hoped to be available in the first quarter of next year.

  15. Virtual acoustics displays

    NASA Astrophysics Data System (ADS)

    Wenzel, Elizabeth M.; Fisher, Scott S.; Stone, Philip K.; Foster, Scott H.

    1991-03-01

    The real time acoustic display capabilities are described which were developed for the Virtual Environment Workstation (VIEW) Project at NASA-Ames. The acoustic display is capable of generating localized acoustic cues in real time over headphones. An auditory symbology, a related collection of representational auditory 'objects' or 'icons', can be designed using ACE (Auditory Cue Editor), which links both discrete and continuously varying acoustic parameters with information or events in the display. During a given display scenario, the symbology can be dynamically coordinated in real time with 3-D visual objects, speech, and gestural displays. The types of displays feasible with the system range from simple warnings and alarms to the acoustic representation of multidimensional data or events.

  16. A method to determine the acoustical properties of locally and nonlocally reacting duct liners in grazing flow

    NASA Technical Reports Server (NTRS)

    Succi, G.

    1982-01-01

    The acoustical properties of locally and nonlocally reacting acoustical liners in grazing flow are described. The effect of mean flow and shear flow are considered as well as the application to rigid and limp bulk reacting materials. The axial wavenumber of the least attenuated mode in a flow duct is measured. The acoustical properties of duct liners is then deduced from the measured axial wavenumber and known flow profile and boundary conditions. This method is a natural extension of impedance-like measurements.

  17. Development of anticavitation hydrophone using a titanium front plate: Effect of the titanium front plate in high-intensity acoustic field with generation of acoustic cavitation

    NASA Astrophysics Data System (ADS)

    Shiiba, Michihisa; Okada, Nagaya; Kurosawa, Minoru; Takeuchi, Shinichi

    2016-07-01

    Novel anticavitation hydrophones were fabricated by depositing a hydrothermally synthesized lead zirconate titanate polycrystalline film at the back of a titanium front plate. These anticavitation hydrophones were not damaged by the measurement of the acoustic field formed by a high-intensity focused ultrasound (HIFU) device. Their sensitivity was improved by approximately 20 dB over that of the conventional anticavitation hydrophone by modifying their basic structure and materials. The durability of the anticavitation hydrophone that we fabricated was compared by exposing it to a high-intensity acoustic field at the focal point of the HIFU field and in the water tank of an ultrasound cleaner. Therefore, the effect of the surface of the titanium front plate on acoustic cavitation was investigated by exposing such a surface to the high-intensity acoustic field. We found that the fabricated anticavitation hydrophone was robust and was not damaged easily, even in the focused acoustic field where acoustic cavitation occurs.

  18. Surface acoustic wave devices for harsh environment wireless sensing

    DOE PAGES

    Greve, David W.; Chin, Tao -Lun; Zheng, Peng; ...

    2013-05-24

    In this study, langasite surface acoustic wave devices can be used to implement harsh environment wireless sensing of gas concentration and temperature. This paper reviews prior work on the development of langasite surface acoustic wave devices, followed by a report of recent progress toward the implementation of oxygen gas sensors. Resistive metal oxide films can be used as the oxygen sensing film, although development of an adherent barrier layer will be necessary with the sensing layers studied here to prevent interaction with the langasite substrate. Experimental results are presented for the performance of a langasite surface acoustic wave oxygen sensormore » with tin oxide sensing layer, and these experimental results are correlated with direct measurements of the sensing layer resistivity.« less

  19. Surface acoustic wave devices for harsh environment wireless sensing

    SciTech Connect

    Greve, David W.; Chin, Tao -Lun; Zheng, Peng; Ohodnicki, Paul; Baltrus, John; Oppenheim, Irving J.

    2013-05-24

    In this study, langasite surface acoustic wave devices can be used to implement harsh environment wireless sensing of gas concentration and temperature. This paper reviews prior work on the development of langasite surface acoustic wave devices, followed by a report of recent progress toward the implementation of oxygen gas sensors. Resistive metal oxide films can be used as the oxygen sensing film, although development of an adherent barrier layer will be necessary with the sensing layers studied here to prevent interaction with the langasite substrate. Experimental results are presented for the performance of a langasite surface acoustic wave oxygen sensor with tin oxide sensing layer, and these experimental results are correlated with direct measurements of the sensing layer resistivity.

  20. Surface Acoustic Wave Devices for Harsh Environment Wireless Sensing

    PubMed Central

    Greve, David W.; Chin, Tao-Lun; Zheng, Peng; Ohodnicki, Paul; Baltrus, John; Oppenheim, Irving J.

    2013-01-01

    Langasite surface acoustic wave devices can be used to implement harsh-environment wireless sensing of gas concentration and temperature. This paper reviews prior work on the development of langasite surface acoustic wave devices, followed by a report of recent progress toward the implementation of oxygen gas sensors. Resistive metal oxide films can be used as the oxygen sensing film, although development of an adherent barrier layer will be necessary with the sensing layers studied here to prevent interaction with the langasite substrate. Experimental results are presented for the performance of a langasite surface acoustic wave oxygen sensor with tin oxide sensing layer, and these experimental results are correlated with direct measurements of the sensing layer resistivity. PMID:23708273

  1. An Acoustical and Physiological Investigation of the Arabic /E/.

    ERIC Educational Resources Information Center

    Al-Ani, Salman H.

    Using acoustical evidence from spectrograms and physiological evidence from X-ray sound films, it appears that the most common allophone for the Arabic voiced pharyngeal fricative, at least in Iraqi, is a voiceless stop, and not a voiced fricative, as many believe. The author considers the phoneme in different environments and describes its…

  2. Surface-Acoustic-Wave Piezoelectric Microbalance

    NASA Technical Reports Server (NTRS)

    Chuan, Raymond L.; Bowers, William D.

    1992-01-01

    Improved piezoelectric microbalances developed for use in measuring masses of volcanic, aerosol, and other small particles suspended in air. Sensitive microbalance used to analyze airborne particles in real time in environments as diverse as clean rooms or upper atmosphere. Surface-acoustic-wave resonator includes input and output sets of interdigitated electrodes and two passive conductive patterns acting as reflectors. Mechanical energy travels both ways out from middle and reflected back toward middle. Microbalance and associated circuitry fit in small package. Circuit draws only 80 mA at 5 V. Sensitivity more than 400 times that of bulk piezoelectric microbalance.

  3. Material Profile Influences in Bulk-Heterojunctions

    SciTech Connect

    Roehling, John D.; Rochester, Christopher W.; Ro, Hyun W.; Wang, Peng; Majewski, Jaroslaw; Batenburg, Kees J.; Arslan, Ilke; Delongchamp, Dean M.; Moule, Adam J.

    2014-10-01

    he morphology in mixed bulk-heterojunction films are compared using three different quantitative measurement techniques. We compare the vertical composition changes using high-angle annular dark-field scanning transmission electron microscopy with electron tomography and neutron and x-ray reflectometry. The three measurement techniques yield qualita-tively comparable vertical concentration measurements. The presence of a metal cathode during thermal annealing is observed to alter the fullerene concentration throughout the thickness of the film for all measurements. However, the abso-lute vertical concentration of fullerene is quantitatively different for the three measurements. The origin of the quantitative measurement differences is discussed. The authors thank Luna Innovations, Inc. for donating the endohedral fullerenes used in this study and Plextronics for the P3HT. They are gratefully thank the National Science Foundation Energy for Sustainability Program, Award No. 0933435. This work benefited from the use of the Lujan Neutron Scattering Center at Los Alamos Neutron Science Center funded by the DOE Office of Basic Energy Sciences and Los Alamos National Laboratory under DOE Contract DE-AC52-06NA25396. This research was also supported in part by Laboratory Directed Research & Development program at PNNL. The Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy under contract DE-AC05-76RL01830.

  4. Cylindrical Micro Ultrasonic Motor Utilizing Bulk Lead Zirconate Titanate (PZT)

    NASA Astrophysics Data System (ADS)

    Morita, Takeshi; Kurosawa, Minoru; Higuchi, Toshiro

    1999-05-01

    Ultrasonic motors are expected to be used as microactuatorsbecause of their high torque, low speed and simple construction. Wehave already reported cylindrical-shaped micro ultrasonic motors whichutilized a lead zirconate titanate (PZT) thin film. In this paper, wediscuss a micro ultrasonic motor composed of bulk PZT. The statortransducer had dimensions of 2.4 mm in diameter and 10 mmlength. The maximum revolution speed was 650 rpm and the maximumoutput torque was 0.22 mNm with the condition of 100 Vp-pinput voltage. The driving frequency was 85 kHz. The comparisonbetween the bulk PZT stator transducer and the previous PZT thin filmtransducer was considered. From this consideration, the e31piezoelectric factor was determined to be the main factor fordifferent output torques. The bulk PZT motor wasapplied to robot hands which was a simple procedure. A two axes hands application was successfully operated with a step motion and carried up to a 10 g load.

  5. Nanosized AlPO{sub 4}-5 molecular sieves and ultrathin films prepared by microwave synthesis

    SciTech Connect

    Mintova, S.; Mo, S.; Bein, T.

    1998-12-01

    Nanosized AlPO{sub 4}-5 molecular sieves and submicron AlPO{sub 4}-5 films were synthesized by microwave treatment of aluminophosphate precursors. The effects of the chemical composition of the initial solution and the conditions of microwave treatment of aluminophosphate precursors on the synthesis of nanosized AlPO{sub 4}-5 molecular sieves were investigated. The syntheses were performed under hydrothermal conditions in a microwave oven at temperatures ranging from 90 to 160 C, using various concentrations of H{sub 2}O and organic template and varying aging times. The resulting bulk products were analyzed using X-ray diffraction, scanning electron microscopy, thermogravimetry, dynamic light scattering, and nitrogen sorption. Optimal conditions for the preparation of nanosized molecular sieve crystals were found. Thin films of AlPO{sub 4}-5 on acoustic wave devices were also prepared, composed of a molecular coupling layer, AlPO{sub 4}-5 seed crystals, and a homogeneous porous film formed by microwave treatment of an aluminophosphate precursor. The initial mixture composition and microwave conditions affect the thickness and the orientation of the zeolite crystals in the films. Sorption isotherms for n-hexane and cyclohexane in these AlPO{sub 4}5 films are reported.

  6. Superconducting RF materials other than bulk niobium: a review

    DOE PAGES

    Valente-Feliciano, Anne-Marie

    2016-09-26

    For the last five decades, bulk niobium (Nb) has been the material of choice for Superconducting RF (SRF) cavity applications. Thin film alternatives such as Nb and other higher-Tc materials, mainly Nb compounds and A15 compounds, have been investigated with moderate effort in the past. In recent years, RF cavity performance has approached the theoretical limit for bulk Nb. For further improvement of RF cavity performance for future accelerator projects, research interest is renewed towards alternatives to bulk Nb. Institutions around the world are now investing renewed efforts in the investigation of Nb thin films and superconductors with higher transitionmore » temperature Tc for application to SRF cavities. Our paper gives an overview of the results obtained so far and challenges encountered for Nb films as well as other materials, such as Nb compounds, A15 compounds, MgB2, and oxypnictides, for SRF cavity applications. An interesting alternative using a Superconductor-Insulator- Superconductor multilayer approach has been recently proposed to delay the vortex penetration in Nb surfaces. This could potentially lead to further improvement in RF cavities performance using the benefit of the higher critical field Hc of higher-Tc superconductors without being limited with their lower Hc1.« less

  7. Superconducting RF materials other than bulk niobium: a review

    SciTech Connect

    Valente-Feliciano, Anne-Marie

    2016-09-26

    For the last five decades, bulk niobium (Nb) has been the material of choice for Superconducting RF (SRF) cavity applications. Thin film alternatives such as Nb and other higher-Tc materials, mainly Nb compounds and A15 compounds, have been investigated with moderate effort in the past. In recent years, RF cavity performance has approached the theoretical limit for bulk Nb. For further improvement of RF cavity performance for future accelerator projects, research interest is renewed towards alternatives to bulk Nb. Institutions around the world are now investing renewed efforts in the investigation of Nb thin films and superconductors with higher transition temperature Tc for application to SRF cavities. Our paper gives an overview of the results obtained so far and challenges encountered for Nb films as well as other materials, such as Nb compounds, A15 compounds, MgB2, and oxypnictides, for SRF cavity applications. An interesting alternative using a Superconductor-Insulator- Superconductor multilayer approach has been recently proposed to delay the vortex penetration in Nb surfaces. This could potentially lead to further improvement in RF cavities performance using the benefit of the higher critical field Hc of higher-Tc superconductors without being limited with their lower Hc1.

  8. Molecular tailoring of interfaces for thin film on substrate systems

    NASA Astrophysics Data System (ADS)

    Grady, Martha Elizabeth

    to use more conventional interfacial fracture testing techniques. Self-assembled monolayers (SAMs) provide an enabling platform for molecular tailoring of the chemical and physical properties of an interface in an on-demand fashion. The SAM end-group functionality is systematically varied and the corresponding effect on interfacial adhesion between a transfer printed gold (Au) film and a fused silica substrate is measured. SAMs with four different end groups are investigated: methyl, amine, bromine and thiol. In addition to these four end groups, mixed monolayers of increasing molar ratio of thiol to methyl SAMs in solution are investigated. There is a strong dependence of interfacial chemistry on the adhesion strength of Au films. In addition to the chemical functionality of the SAM, surface roughness of the underlying substrate also has a significant impact on the interfacial strength. Thin films of mechanochemically active polymer are subjected to laser-generated, high amplitude acoustic pulses. Stress wave propagation through the film produces large amplitude stresses (>100 MPa) in short time frames (10-20 ns), leading to very high strain-rates (ca. 107-108 s -1). The polymer system, spiropyran (SP)- linked polystyrene (PS), undergoes a force-induced chemical reaction causing fluorescence and color change. Activation of SP is evident via a fluorescence signal in thin films subject to high strain-rates. In contrast, quasi-static loading of bulk SP-linked PS samples failed to result in SP activation. Mechanoresponsive coatings have potential to indicate deformation under shockwave loading conditions. In addition to SP-linked polymer films, the activation of spiropyran interfacial molecules with different side groups is characterized as they adsorb onto a SAM platform with preferential amine terminating chemistry. The reactivity of SP monolayers due to UV irradiation is evaluated by water contact angle goniometry and fluorescence spectroscopy. Side groups on the

  9. Acoustic mapping velocimetry

    NASA Astrophysics Data System (ADS)

    Muste, M.; Baranya, S.; Tsubaki, R.; Kim, D.; Ho, H.; Tsai, H.; Law, D.

    2016-05-01

    Knowledge of sediment dynamics in rivers is of great importance for various practical purposes. Despite its high relevance in riverine environment processes, the monitoring of sediment rates remains a major and challenging task for both suspended and bed load estimation. While the measurement of suspended load is currently an active area of testing with nonintrusive technologies (optical and acoustic), bed load measurement does not mark a similar progress. This paper describes an innovative combination of measurement techniques and analysis protocols that establishes the proof-of-concept for a promising technique, labeled herein Acoustic Mapping Velocimetry (AMV). The technique estimates bed load rates in rivers developing bed forms using a nonintrusive measurements approach. The raw information for AMV is collected with acoustic multibeam technology that in turn provides maps of the bathymetry over longitudinal swaths. As long as the acoustic maps can be acquired relatively quickly and the repetition rate for the mapping is commensurate with the movement of the bed forms, successive acoustic maps capture the progression of the bed form movement. Two-dimensional velocity maps associated with the bed form migration are obtained by implementing algorithms typically used in particle image velocimetry to acoustic maps converted in gray-level images. Furthermore, use of the obtained acoustic and velocity maps in conjunction with analytical formulations (e.g., Exner equation) enables estimation of multidirectional bed load rates over the whole imaged area. This paper presents a validation study of the AMV technique using a set of laboratory experiments.

  10. Acoustic cooling engine

    DOEpatents

    Hofler, Thomas J.; Wheatley, John C.; Swift, Gregory W.; Migliori, Albert

    1988-01-01

    An acoustic cooling engine with improved thermal performance and reduced internal losses comprises a compressible fluid contained in a resonant pressure vessel. The fluid has a substantial thermal expansion coefficient and is capable of supporting an acoustic standing wave. A thermodynamic element has first and second ends and is located in the resonant pressure vessel in thermal communication with the fluid. The thermal response of the thermodynamic element to the acoustic standing wave pumps heat from the second end to the first end. The thermodynamic element permits substantial flow of the fluid through the thermodynamic element. An acoustic driver cyclically drives the fluid with an acoustic standing wave. The driver is at a location of maximum acoustic impedance in the resonant pressure vessel and proximate the first end of the thermodynamic element. A hot heat exchanger is adjacent to and in thermal communication with the first end of the thermodynamic element. The hot heat exchanger conducts heat from the first end to portions of the resonant pressure vessel proximate the hot heat exchanger. The hot heat exchanger permits substantial flow of the fluid through the hot heat exchanger. The resonant pressure vessel can include a housing less than one quarter wavelength in length coupled to a reservoir. The housing can include a reduced diameter portion communicating with the reservoir. The frequency of the acoustic driver can be continuously controlled so as to maintain resonance.

  11. Acoustic sniper localization system

    NASA Astrophysics Data System (ADS)

    Prado, Gervasio; Dhaliwal, Hardave; Martel, Philip O.

    1997-02-01

    Technologies for sniper localization have received increased attention in recent months as American forces have been deployed to various trouble spots around the world. Among the technologies considered for this task acoustics is a natural choice for various reasons. The acoustic signatures of gunshots are loud and distinctive, making them easy to detect even in high noise background environments. Acoustics provides a passive sensing technology with excellent range and non line of sight capabilities. Last but not least, an acoustic sniper location system can be built at a low cost with off the shelf components. Despite its many advantages, the performance of acoustic sensors can degrade under adverse propagation conditions. Localization accuracy, although good, is usually not accurate enough to pinpoint a sniper's location in some scenarios (for example which widow in a building or behind which tree in a grove). For these more demanding missions, the acoustic sensor can be used in conjunction with an infra red imaging system that detects the muzzle blast of the gun. The acoustic system can be used to cue the pointing system of the IR camera in the direction of the shot's source.

  12. Polydimethylsiloxane thin film characterization using all-optical photoacoustic mechanism.

    PubMed

    Zou, Xiaotian; Wu, Nan; Tian, Ye; Zhang, Yang; Wang, Xingwei

    2013-09-01

    This paper presents a nondestructive ultrasound testing method for characterization of the resonant frequencies of polydimethylsiloxane (PDMS) thin film by using a miniature fiber optic photoacoustic (PA) probe. The PA probe was fabricated with an optical fiber and a synthesized gold nanocomposite. During the experiment, a cured PDMS thin film with a thickness of 220 μm was immersed into a water medium using a custom-designed holder to clamp the film. An acoustic pulse was generated by the PA probe and propagated through the water media to excite the fixed film. A fiber optic pressure sensor based on the Fabry-Perot principle was used to collect the excited acoustic signals on the other side of the film. The acquired response of the acoustic pulse was used to compute the resonant frequencies of the PDMS thin film based on a deconvolution method.

  13. Mars Acoustic Anemometer

    NASA Astrophysics Data System (ADS)

    Banfield, D. J.

    2012-12-01

    is far less susceptible to contaminating influences as other techniques (e.g., hot wire/hot film) that have been used for anemometry at Mars. Our instrument is conceptually derived from the commercial terrestrial sonic anemometers, but uses specialized acoustic transducers to optimally couple with the low density martian air as well as survive the extreme temperature swings on Mars. Additionally, we use sophisticated signal processing to extract as much information as possible in the low S/N environment that is achievable at Mars. We have developed our instrument through to TRL 5, proving it in a martian wind tunnel in Denmark. We found wind speed sensitivities and precision to be of order 3 cm/s, and with appropriate calibration, accuracy can be similar, even when operating at 20-100 Hz. We will also test this instrument at 120,000' altitude (i.e., equivalent to Mars atmospheric density) as an autonomous package on a stratospheric balloon. We are currently developing a TRL 6 version of the instrument that will be tested once again in the Denmark Mars Wind Tunnel. We expect our flight configuration instrument to be about 1 kg, including a 1.5m mast. It will also draw about 2-3W of power. This instrument is now ready to be proposed for future Mars missions, where we believe it will make a significant contribution and a step forward in Mars atmospheric science.

  14. Self-Limited Growth in Pentacene Thin Films

    PubMed Central

    2017-01-01

    Pentacene is one of the most studied organic semiconducting materials. While many aspects of the film formation have already been identified in very thin films, this study provides new insight into the transition from the metastable thin-film phase to bulk phase polymorphs. This study focuses on the growth behavior of pentacene within thin films as a function of film thickness ranging from 20 to 300 nm. By employing various X-ray diffraction methods, combined with supporting atomic force microscopy investigations, one crystalline orientation for the thin-film phase is observed, while three differently tilted bulk phase orientations are found. First, bulk phase crystallites grow with their 00L planes parallel to the substrate surface; second, however, crystallites tilted by 0.75° with respect to the substrate are found, which clearly dominate the former in ratio; third, a different bulk phase polymorph with crystallites tilted by 21° is found. The transition from the thin-film phase to the bulk phase is rationalized by the nucleation of the latter at crystal facets of the thin-film-phase crystallites. This leads to a self-limiting growth of the thin-film phase and explains the thickness-dependent phase behavior observed in pentacene thin films, showing that a large amount of material is present in the bulk phase much earlier during the film growth than previously thought. PMID:28287698

  15. Adaptive Back Sheet Material for Acoustic Liner Applications-ARMD Seedling Fund Phase I Final Report

    NASA Technical Reports Server (NTRS)

    Gerhold, Carl H.; Jones, Michael G.; Farrar, Dawnielle

    2014-01-01

    A recently developed piezo-electric composite film is evaluated for its usefulness in application in acoustic liners. Researchers at the NASA Langley Research Center Liner Technology Facility developed experiments to measure the electrical response of the material to acoustic excitation and the vibrational response of the material to electrical excitation. The robustness of the piezo-electric film was also assessed. The material's electrical response to acoustic excitation is found to be comparable to a commercial microphone in the range of frequencies from 500 to 3000 Hz. However, the vibrational response to electrical excitation in the frequency range of interest is an order of magnitude less than may be necessary for application to acoustic liners. Nevertheless, experimental results indicate that the potential exists for the material to produce a measurable change in the impedance spectrum of a liner. Work continues to improve the authority of the piezo-electric film.

  16. Lonsdaleite Films with Nanometer Thickness.

    PubMed

    Kvashnin, Alexander G; Sorokin, Pavel B

    2014-02-06

    We investigate the properties of potentially the stiffest quasi-2-D films with lonsdaleite structure. Using a combination of ab initio and empirical potential approaches, we analyze the elastic properties of lonsdaleite films in both elastic and inelastic regimes and compare them with graphene and diamond films. We review possible fabrication methods of lonsdaleite films using the pure nanoscale "bottom-up" paradigm: by connecting carbon layers in multilayered graphene. We propose the realization of this method in two ways: by applying direct pressure and by using the recently proposed chemically induced phase transition. For both cases, we construct the phase diagrams depending on temperature, pressure, and film thickness. Finally, we consider the electronic properties of lonsdaleite films and establish the nonlinear dependence of the band gap on the films' thicknesses and their lower effective masses in comparison with bulk crystal.

  17. Experimental and numerical investigation of Acoustic streaming (Eckart streaming)

    NASA Astrophysics Data System (ADS)

    Dridi, Walid; Botton, Valery; Henry, Daniel; Ben Hadid, Hamda

    The application of sound waves in the bulk of a fluid can generate steady or quasi-steady flows reffered to as Acoustic streaming flows. We can distinguish two kind of acoustic streaming: The Rayleigh Streaming is generated when a standing acoustic waves interfere with solid walls to give birth to an acoustic boundary layer. Steady recirculations are then driven out of the boundary layer and can be used in micro-gravity, where the free convection is too weak or absent, to enhance the convective heat or mass transfer and cooling the electronic devises [1]. The second kind is the Eckart streaming, which is a flow generated far from the solid boundaries, it can be used to mix a chemical solutions [2], and to drive a viscous liquids in channels [3-4], in micro-gravity area. Our study focuses on the Eckart streaming configuration, which is investigated both numerical and experimental means. The experimental configuration is restricted to the case of a cylindrical non-heated cavity full of water or of a water+glycerol mixture. At the middle of one side of the cavity, a plane ultrasonic transducer generates a 2MHz wave; an absorber is set at the opposite side of the cavity to avoid any reflections. The velocity field is measured with a standard PIV system. [1] P. Vainshtein, M. Fichman and C. Gutfinger, "Acoustic enhancement of heat transfer between two parallel plates", International Journal of Heat and Mass Transfert, 1995, 38(10), 1893. [2] C. Suri, K. Tekenaka, H. Yanagida, Y. Kojima and K. Koyama, "Chaotic mixing generated by acoustic streaming", Ultrasonics, 2002, 40, 393 [3] O.V. Rudenko and A.A. Sukhorukov, "Nonstationnary Eckart streaming and pumping of liquid in ultrasonic field", Acoustical Physics, 1998, 44, 653. [4] Kenneth D. Frampton, Shawn E. Martin and Keith Minor, "The scaling of acoustic streaming for application in micro-fluidic devices", Applied Acoustics, 2003, 64,681

  18. The room acoustic rendering equation.

    PubMed

    Siltanen, Samuel; Lokki, Tapio; Kiminki, Sami; Savioja, Lauri

    2007-09-01

    An integral equation generalizing a variety of known geometrical room acoustics modeling algorithms is presented. The formulation of the room acoustic rendering equation is adopted from computer graphics. Based on the room acoustic rendering equation, an acoustic radiance transfer method, which can handle both diffuse and nondiffuse reflections, is derived. In a case study, the method is used to predict several acoustic parameters of a room model. The results are compared to measured data of the actual room and to the results given by other acoustics prediction software. It is concluded that the method can predict most acoustic parameters reliably and provides results as accurate as current commercial room acoustic prediction software. Although the presented acoustic radiance transfer method relies on geometrical acoustics, it can be extended to model diffraction and transmission through materials in future.

  19. PRSEUS Acoustic Panel Fabrication

    NASA Technical Reports Server (NTRS)

    Nicolette, Velicki; Yovanof, Nicolette P.; Baraja, Jaime; Mathur, Gopal; Thrash, Patrick; Pickell, Robert

    2011-01-01

    This report describes the development of a novel structural concept, Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS), that addresses the demanding fuselage loading requirements for the Hybrid Wing or Blended Wing Body (BWB) airplane configuration with regards to acoustic response. A PRSEUS panel was designed and fabricated and provided to NASA-LaRC for acoustic response testing in the Structural Acoustics Loads and Transmission (SALT) facility). Preliminary assessments of the sound transmission characteristics of a PRSEUS panel subjected to a representative Hybrid Wing Body (HWB) operating environment were completed for the NASA Environmentally Responsible Aviation (ERA) Program.

  20. Acoustic well cleaner

    DOEpatents

    Maki, Jr., Voldi E.; Sharma, Mukul M.

    1997-01-21

    A method and apparatus are disclosed for cleaning the wellbore and the near wellbore region. A sonde is provided which is adapted to be lowered into a borehole and which includes a plurality of acoustic transducers arranged around the sonde. Electrical power provided by a cable is converted to acoustic energy. The high intensity acoustic energy directed to the borehole wall and into the near wellbore region, redissolves or resuspends the material which is reducing the permeability of the formation and/or restricting flow in the wellbore.