WorldWideScience

Sample records for high sensitivity array

  1. Research of High Sensitivity Uncooled Infrared Detector Array

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Pingchuan [Huazhong University of Science and Technology, Wuhan 430074 (China); Zhang, Bo, E-mail: redmoon123456@126.com, E-mail: lhzyzb@126.com [Luohe Vocational Technology College, Luohe 462002 (China)

    2011-02-01

    The infrared thermal imaging technology has been widely used in military and civilian fields and the field of the infrared detection and infrared thermal imaging technology has been of concern for a long time. On infrared thermal imaging, its core components for the infrared focal plane arrays, how to develop a high sensitivity of the multi-focal plane infrared detector is a key issue. Although the Common focal plane array of quantum has high sensitivity, but it requires low temperature cooling work environment and led to complexity and high cost, difficult to compact. Conventional uncooled infrared focal plane array is contrast to the quantum focal plane arrays. Therefore, this article preceded by the uncooled infrared detector array to improve the wide temperature sensitivity in examining the feasibility PMN composite film, materials composition, structure design and preparation process technology.

  2. Magnetic probe array with high sensitivity for fluctuating field.

    Science.gov (United States)

    Kanamaru, Yuki; Gota, Hiroshi; Fujimoto, Kayoko; Ikeyama, Taeko; Asai, Tomohiko; Takahashi, Tsutomu; Nogi, Yasuyuki

    2007-03-01

    A magnetic probe array is constructed to measure precisely the spatial structure of a small fluctuating field included in a strong confinement field that varies with time. To exclude the effect of the confinement field, the magnetic probes consisting of figure-eight-wound coils are prepared. The spatial structure of the fluctuating field is obtained from a Fourier analysis of the probe signal. It is found that the probe array is more sensitive to the fluctuating field with a high mode number than that with a low mode number. An experimental demonstration of the present method is attempted using a field-reversed configuration plasma, where the fluctuating field with 0.1% of the confinement field is successfully detected.

  3. High Sensitivity Indium Phosphide Based Avalanche Photodiode Focal Plane Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — nLight has demonstrated highly-uniform APD arrays based on the highly sensitive InGaAs/InP material system. These results provide great promise for achieving the...

  4. High-sensitivity high-throughput chip based biosensor array for multiplexed detection of heavy metals

    Science.gov (United States)

    Yan, Hai; Tang, Naimei; Jairo, Grace A.; Chakravarty, Swapnajit; Blake, Diane A.; Chen, Ray T.

    2016-03-01

    Heavy metal ions released into the environment from industrial processes lead to various health hazards. We propose an on-chip label-free detection approach that allows high-sensitivity and high-throughput detection of heavy metals. The sensing device consists of 2-dimensional photonic crystal microcavities that are combined by multimode interferometer to form a sensor array. We experimentally demonstrate the detection of cadmium-chelate conjugate with concentration as low as 5 parts-per-billion (ppb).

  5. High-Sensitivity Phased Arrays for Radio Astronomy and Satellite Communications

    Science.gov (United States)

    Diao, Junming

    Radio astronomy is used to study stars, galaxies, black holes and gas clouds radiation at radio frequencies. Detecting extremely weak signals from deep space radio sources requires high sensitive feed system associated with large dish antennas. The key figure of merit is survey speed, or the time required to map a region of the sky to a given source flux density. Survey speed is proportional to the frequency bandwidth, the field of view or observable region of the sky, and the squared sensitivity, where sensitivity is related to reflector aperture efficiency and system noise temperature. Compared to the traditional single feed, phased array feeds with significantly expanded field of view are considered as the next generation feed for radio telescope. This dissertation outlines the design, analysis and measurement of high sensitivity L-band and mm-wave phased array feeds for the 100-meter Green Bank Telescope. Theoretical works for radio astronomy includes design guideline for high sensitivity phased array feed, fundamental frequency bandwidth limit, array antenna loss influenced by mutual coupling and beamformer coefficients and possibility of superdirectivity for radio telescopes and other antennas. These study are helpful to understand and guide the design of a phased array feed system. In the absence of dish antennas, sparse phased arrays with aperiodic structure have been developed for satellite communications. A compromise between the peak side lobe level, array element density, directivity and design complexity is studied. We have found that the array peak side lobe level can be reduced by enhancing the array element direction at the main lobe direction, increasing the array element density and enlarging the array size. A Poynting streamline approach develops to understand the properties of a receiving antenna and the mutual coupling effects between array elements. This method has been successfully used to generate effective area shape for many types of

  6. Highly sensitive glucose biosensor based on Au-Ni coaxial nanorod array having high aspect ratio.

    Science.gov (United States)

    Hsu, Che-Wei; Wang, Gou-Jen

    2014-06-15

    An effective glucose biosensor requires a sufficient amount of GOx immobilizing on the electrode surface. An electrode of a 3D nanorod array, having a larger surface-to-volume ratio than a 2D nanostructure, can accommodate more GOx molecules to immobilize onto the surface of the nanorods. In this study, a highly sensitive Au-Ni coaxial nanorod array electrode fabricated through the integration of nano electroforming and immersion gold (IG) method for glucose detection was developed. The average diameter of the as-synthesized Ni nanorods and that of the Au-Ni nanorods were estimated to be 150 and 250 nm, respectively; both had a height of 30 μm. The aspect ratio was 120. Compared to that of a flat Au electrode, the effective sensing area was enhanced by 79.8 folds. Actual glucose detections demonstrated that the proposed Au-Ni coaxial nanorod array electrode could operate in a linear range of 27.5 μM-27.5mM with a detection limit of 5.5μM and a very high sensitivity of 769.6 μA mM(-1)cm(-2). Good selectivity of the proposed sensing device was verified by sequential injections of uric acid (UA) and ascorbic acid (AA). Long-term stability was examined through successive detections over a period of 30 days.

  7. Fully printed, highly sensitive multifunctional artificial electronic whisker arrays integrated with strain and temperature sensors.

    Science.gov (United States)

    Harada, Shingo; Honda, Wataru; Arie, Takayuki; Akita, Seiji; Takei, Kuniharu

    2014-04-22

    Mammalian-mimicking functional electrical devices have tremendous potential in robotics, wearable and health monitoring systems, and human interfaces. The keys to achieve these devices are (1) highly sensitive sensors, (2) economically fabricated macroscale devices on flexible substrates, and (3) multifunctions beyond mammalian functions. Although highly sensitive artificial electronic devices have been reported, none have been fabricated using cost-effective macroscale printing methods and demonstrate multifunctionalities of artificial electronics. Herein we report fully printed high-sensitivity multifunctional artificial electronic whiskers (e-whisker) integrated with strain and temperature sensors using printable nanocomposite inks. Importantly, changing the composition ratio tunes the sensitivity of strain. Additionally, the printed temperature sensor array can be incorporated with the strain sensor array beyond mammalian whisker functionalities. The sensitivity for the strain sensor is impressively high (∼59%/Pa), which is the best sensitivity reported to date (>7× improvement). As the proof-of-concept for a truly printable multifunctional artificial e-whisker array, two- and three-dimensional space and temperature distribution mapping are demonstrated. This fully printable flexible sensor array should be applicable to a wide range of low-cost macroscale electrical applications.

  8. Preparation and hydrogen 8as sensitive characteristics of highly ordered titania nanotube arrays

    Institute of Scientific and Technical Information of China (English)

    JI HuiMing; LU HuiXiang; MA DongFang; YU JianJun; MA ShiCai

    2008-01-01

    In this paper, we report the growth and characteristics of titania nanotube arrays prepared by anodic oxidation and then annealed in an oxygen atmosphere at 500℃. The titania nanotube arrays presented high sensitivity to hydrogen gas. The crystalline phase of the samples was checked by X-ray diffraction (XRD). The differences in the nanotubes morphology attributed to the etched samples due to anodiza-tion potential, reaction time and the electrolyte concentration were analyzed by scanning electron mi-croscopy (SEM). The gas sensitive parameters of the samples were obtained from resistance, the re-sponse time and the recovery time at different temperatures.

  9. Standoff photoacoustic detections with high-sensitivity microphones and acoustic arrays

    Science.gov (United States)

    Choa, Fow-Sen; Wang, Chen-Chia; Khurgin, Jacob; Samuels, Alan; Trivedi, Sudhir; Gupta, Deepa

    2016-05-01

    Standoff detection of dangerous chemicals like explosives, nerve gases, and harmful aerosols has continuously been an important subject due to the serious concern about terrorist threats to both overseas and homeland lives and facility. Compared with other currently available standoff optical detection techniques, like Raman, photo-thermal, laser induced breakdown spectroscopy,...etc., photoacoustic (PA) sensing has the advantages of background free and very high detection sensitivity, no need of back reflection surfaces, and 1/R instead of 1/R2 signal decay distance dependence. Furthermore, there is still a great room for PA sensitivity improvement by using different PA techniques, including lockin amplifier, employing new microphones, and microphone array techniques. Recently, we have demonstrated standoff PA detection of isopropanol vapor, solid phase TNT and RDX at a standoff distance. To further calibrate the detection sensitivity, we use nerve gas simulants that were generated and calibrated by a commercial vapor generator. For field operations, array of microphones and microphone-reflector pairs can be utilized to achieve noise rejection and signal enhancement. We have experimentally demonstrated signal enhancement and noise reduction using an array of 4 microphone/4 reflector system as well as an array of 16-microphone/1 reflector. In this work we will review and compare different standoff techniques and discuss the advantages of using different photoacoustic techniques. We will also discuss new advancement of using new types of microphone and the performance comparison of using different structure of microphone arrays and combining lock-in amplifier with acoustic arrays. Demonstration of out-door real-time operations with high power mid-IR laser and microphone array will be presented.

  10. Highly Transparent Dual-Sensitized Titanium Dioxide Nanotube Arrays for Spontaneous Solar Water Splitting Tandem Configuration.

    Science.gov (United States)

    Shin, Kahee; Park, Jong Hyeok

    2015-08-26

    Vertically aligned one-dimensional (1D) titanium dioxide (TiO2) arrays on transparent conducting oxide (TCO) substrates, which can act as host electron transport materials for low bandgap materials, were synthesized via a hydrothermal reaction combined with a controlled chemical etching process. By controlling the chemical etching conditions, we can maximize the light transmission properties of the 1D TiO2 arrays, which is beneficial for the front electrode in photoelectrochemical (PEC) tandem configurations. As a result, dual sensitization to form 1D TiO2@CdS@CdSe (CdS and CdSe coated 1D TiO2) results in excellent photocurrent density, as well as transparency, and the resulting material is able to pass unabsorbed photons through the front electrode into the rear bias solar cell. Owing to the improved light transmission in combination with the increased specific surface area of the obtained 1D TiO2 arrays from the controlled etching process, a high-efficiency PEC tandem device with ∼2.1% was successfully fabricated for unassisted hydrogen evolution. Efficient PEC tandem device was fabricated for unassisted solar hydrogen generation using highly transparent composite electrode composed of dual sensitization to form 1D TiO2@CdS@CdSe.

  11. Highly sensitive label-free dual sensor array for rapid detection of wound bacteria.

    Science.gov (United States)

    Sheybani, Roya; Shukla, Anita

    2017-06-15

    Wound infections are a critical healthcare concern worldwide. Rapid and effective antibiotic treatments that can mitigate infection severity and prevent the spread of antibiotic resistance are contingent upon timely infection detection. In this work, dual electrochemical pH and cell-attachment sensor arrays were developed for the real-time spatial and temporal monitoring of potential wound infections. Biocompatible polymeric device coatings were integrated to stabilize the sensors and promote bacteria attachment while preventing non-specific cell and protein fouling. High sensitivity (bacteria concentration of 10(2) colony forming units (CFU)/mL and -88.1±6.3mV/pH over a pH range of 1-13) and stability over 14 days were achieved without the addition of biological recognition elements. The dual sensor array was demonstrated to successfully monitor the growth of both gram-positive (Staphylococcus aureus and Streptococcus pyogenes) and gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli) over time through lag and log growth phases and following antibiotic administration and in simulated shallow wounds conditions. The versatile fabrication methods utilized in sensor development, superior sensitivity, prolonged stability, and lack of non-specific sensor fouling may enable long-term in situ sensor array operation in low resource settings. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. High reproducibility and sensitivity of bifacial copper nanowire array for detection of glucose

    Directory of Open Access Journals (Sweden)

    Hanqing Zhang

    2017-06-01

    Full Text Available The ordered bifacial copper nanowire array (Cu BNWA was synthesized by a template assisted electrochemical deposition method. The morphology and structure of the as-prepared samples were investigated by field emission scanning electron microscope (FESEM and X-ray diffraction (XRD. The results show that the ordered Cu nanowire array with uniform geometrical dimensions covered both side of the Cu substrate. When used as the electrode for glucose detection, the minimum detectable concentration of glucose can be reached as low as 0.2 mM. Impressively, the sample still showed high sensitivity and stability for glucose detection after two months placement in ambient environment. These excellent performances of the Cu BNWA make it a promising non-enzyme glucose detection sensor for various applications.

  13. High sensitive photonic crystal multiplexed biosensor array using H0 sandwiched cavities

    Science.gov (United States)

    Arafa, Safia; Bouchemat, Mohamed; Bouchemat, Touraya; Benmerkhi, Ahlem

    2017-03-01

    We theoretically investigate a high sensitive photonic crystal integrated biosensor array structure which is potentially used for label-free multiplexed sensing. The proposed device consists of an array of three sandwiched H0 cavities patterned above silicon on insulator (SOI) substrate; each cavity has been designed for different cavity spacing and different resonant wavelength. Results obtained by performing finite-difference time-domain (FDTD) simulations, indicate that the response of each detection unit shifts independently in terms of refractive index variations. The optimized design makes possible the combination of sensing as a function of location, as well as a function of time in the same platform. A refractive index sensitivity of 520nm/RIU and a quality factor over 104 are both achieved with an accompanied crosstalk of less than -26 dB. In addition, the device presents an improved detection limit (DL) of 1.24.10-6 RIU and a wide measurement range. These features make the designed device a promising element for performing label-free multiplexed detection in monolithic substrate for medical diagnostics and environmental monitoring.

  14. High sensitive photonic crystal multiplexed biosensor array using H0 sandwiched cavities

    Directory of Open Access Journals (Sweden)

    Arafa Safia

    2017-01-01

    Full Text Available We theoretically investigate a high sensitive photonic crystal integrated biosensor array structure which is potentially used for label-free multiplexed sensing. The proposed device consists of an array of three sandwiched H0 cavities patterned above silicon on insulator (SOI substrate; each cavity has been designed for different cavity spacing and different resonant wavelength. Results obtained by performing finite-difference time-domain (FDTD simulations, indicate that the response of each detection unit shifts independently in terms of refractive index variations. The optimized design makes possible the combination of sensing as a function of location, as well as a function of time in the same platform. A refractive index sensitivity of 520nm/RIU and a quality factor over 104 are both achieved with an accompanied crosstalk of less than -26 dB. In addition, the device presents an improved detection limit (DL of 1.24.10-6 RIU and a wide measurement range. These features make the designed device a promising element for performing label-free multiplexed detection in monolithic substrate for medical diagnostics and environmental monitoring.

  15. Fabrication and characterization of gold nanocrown arrays on a gold film for a high-sensitivity surface plasmon resonance biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Munsik; Kim, Nak-hyeon; Eom, Seyoung [Department of Biomedical Engineering, Kyung Hee University, Yongin 446-701 (Korea, Republic of); Kim, Tae Woo [School of East–West Medical Science, Kyung Hee University, Yongin 446-701 (Korea, Republic of); Byun, Kyung Min, E-mail: kmbyun@khu.ac.kr [Department of Biomedical Engineering, Kyung Hee University, Yongin 446-701 (Korea, Republic of); Park, Hyeong-Ho, E-mail: hyeongho.park@kanc.re.kr [Nano Process Division, Korea Advanced Nano Fab Center, Suwon 443-270 (Korea, Republic of)

    2015-07-31

    We report on a versatile method to fabricate gold nanocrown arrays on a thin gold film based on ultraviolet nanoimprint lithography and tilted evaporation technique. We realize highly ordered 2-dimensional nanocrown arrays and characterize their sizes and morphologies using scanning electron microscopy. To demonstrate an enhanced surface plasmon resonance (SPR) detection by the fabricated gold nanocrown samples, biosensing experiments are performed by measuring SPR angle shift for biotin–streptavidin interaction and bulk refractive index change of dielectric medium. We hope that the suggested plasmonic platform with a high sensitivity could be extended to a variety of biomolecular binding reactions. - Highlights: • Gold nanocrown arrays are produced by nanoimprint lithography and tilted evaporation. • Use of gold nanocrown arrays can improve the sensor sensitivity significantly. • Improved sensitivity is due to enhanced field–matter interaction at gold nanocrowns.

  16. High Sensitivity Terahertz Detection through Large-Area Plasmonic Nano-Antenna Arrays

    Science.gov (United States)

    Yardimci, Nezih Tolga; Jarrahi, Mona

    2017-01-01

    Plasmonic photoconductive antennas have great promise for increasing responsivity and detection sensitivity of conventional photoconductive detectors in time-domain terahertz imaging and spectroscopy systems. However, operation bandwidth of previously demonstrated plasmonic photoconductive antennas has been limited by bandwidth constraints of their antennas and photoconductor parasitics. Here, we present a powerful technique for realizing broadband terahertz detectors through large-area plasmonic photoconductive nano-antenna arrays. A key novelty that makes the presented terahertz detector superior to the state-of-the art is a specific large-area device geometry that offers a strong interaction between the incident terahertz beam and optical pump at the nanoscale, while maintaining a broad operation bandwidth. The large device active area allows robust operation against optical and terahertz beam misalignments. We demonstrate broadband terahertz detection with signal-to-noise ratio levels as high as 107 dB. PMID:28205615

  17. High Sensitivity Terahertz Detection through Large-Area Plasmonic Nano-Antenna Arrays

    Science.gov (United States)

    Yardimci, Nezih Tolga; Jarrahi, Mona

    2017-02-01

    Plasmonic photoconductive antennas have great promise for increasing responsivity and detection sensitivity of conventional photoconductive detectors in time-domain terahertz imaging and spectroscopy systems. However, operation bandwidth of previously demonstrated plasmonic photoconductive antennas has been limited by bandwidth constraints of their antennas and photoconductor parasitics. Here, we present a powerful technique for realizing broadband terahertz detectors through large-area plasmonic photoconductive nano-antenna arrays. A key novelty that makes the presented terahertz detector superior to the state-of-the art is a specific large-area device geometry that offers a strong interaction between the incident terahertz beam and optical pump at the nanoscale, while maintaining a broad operation bandwidth. The large device active area allows robust operation against optical and terahertz beam misalignments. We demonstrate broadband terahertz detection with signal-to-noise ratio levels as high as 107 dB.

  18. High sensitive immunoassay for multiplex mycotoxin detection with photonic crystal microsphere suspension array.

    Science.gov (United States)

    Deng, Guozhe; Xu, Kun; Sun, Yue; Chen, Yu; Zheng, Tiesong; Li, Jianlin

    2013-03-05

    A novel, sensitive, and high throughput competitive immunoassay for multiplex mycotoxins was established by immobilizing the artificial antigens (Ags) of mycotoxins on the surfaces of three kinds of silica photonic crystal microsphere (SPCM) suspension arrays. The SPCMs were encoded by their reflectance peak positions. Aflatoxin B1 (AFB1), fumonisin B1 (FB1), and citrinin (CIT) spiked in the cereals were extracted, and the fluorescein isothiocyanate (FITC) labeled antibodies (Abs) of these mycotoxins were added into the centrifuge tube which contained the SPCMs of the modified artificial antigens (Ags). The fluorescence signal was collected by an array fluorescent scanner. The limit of detection (LOD) was as low as 0.5, 1, and 0.8 pg/mL for AFB1, FB1, and CIT, respectively. The new method provided a wide linear detection range from 0.001 to 10, 0.001 to 10, and 0.001 to 1 ng/mL for AFB1, FB1, and CIT, respectively. The mean recovery rates are in range of 74.7 ± 4.0% to 127.9 ± 4.4% for the three mycotoxins in corn, peanuts, and wheat. The developed method for mycotoxins was used to assay the AFB1, FB1, and CIT level in 10 naturally contaminated cereal samples, and the results of detection were in agreement with that of a classic enzyme-linked immunosorbent assay (ELISA) method. This method saves a large amount of reagents (10 μL volume) and detection time (<3 h) for multiplex mycotoxin assay.

  19. Dye-sensitized photovoltaic wires using highly ordered TiO2 nanotube arrays.

    Science.gov (United States)

    Liu, Zhaoyue; Misra, Mano

    2010-04-27

    Dye-sensitized photovoltaic wires (DSPVWs) are developed using anodized Ti wires that contain ordered arrays of TiO2 nanotubes. The prototype DSPVW consists of N719 dye-adsorbed TiO2 nanotube arrays around a Ti wire as a working electrode, a platinum wire as a counter electrode, and an organic electrolyte encased in a capillary glass tube. The effect of length of nanotube arrays on the photovoltaic performance of DSPVWs is studied systematically. A solar-to-electric conversion efficiency of 2.78% is achieved with 55 microm long nanotubes under 98.3 mW/cm(2) AM 1.5 simulated full light. The prototype device is capable of achieving a long distance transport of photocurrent and harvesting all light from any direction in surroundings to generate electricity.

  20. Organization of vagal afferents in pylorus: mechanoreceptors arrayed for high sensitivity and fine spatial resolution?

    Science.gov (United States)

    Powley, Terry L; Hudson, Cherie N; McAdams, Jennifer L; Baronowsky, Elizabeth A; Martin, Felecia N; Mason, Jacqueline K; Phillips, Robert J

    2014-07-01

    The pylorus is innervated by vagal mechanoreceptors that project to gastrointestinal smooth muscle, but the distributions and specializations of vagal endings in the sphincter have not been fully characterized. To evaluate their organization, the neural tracer dextran biotin was injected into the nodose ganglia of rats. Following tracer transport, animals were perfused, and their pylori and antra were prepared as whole mounts. Specimens were processed to permanently label the tracer, and subsets were counterstained with Cuprolinic blue or immunostained for c-Kit. Intramuscular arrays (IMAs) in the circular muscle comprised the principal vagal afferent innervation of the sphincter. These pyloric ring IMAs were densely distributed and evidenced a variety of structural specializations. Morphometric comparisons between the arbors innervating the pylorus and a corresponding sample of IMAs in the adjacent antral circular muscle highlighted that sphincter IMAs branched profusely, forming more than twice as many branches as did antral IMAs (means of 405 vs. 165, respectively), and condensed their numerous neurites into compact receptive fields (∼48% of the area of antral IMAs) deep in the circular muscle (∼6μm above the submucosa). Separate arbors of IMAs in the sphincter interdigitated and overlapped to form a 360° band of mechanoreceptors encircling the pyloric canal. The annulus of vagal IMA arbors, putative stretch receptors tightly intercalated in the sphincter ring and situated near the lumen of the pyloric canal, creates an architecture with the potential to generate gut reflexes on the basis of pyloric sensory maps of high sensitivity and fine spatial resolution.

  1. Frequency and sensitivity tunable microresonator array for high-speed quantum processor readout

    Science.gov (United States)

    Hoskinson, Emile; Whittaker, J. D.; Swenson, L. J.; Volkmann, M. H.; Spear, P.; Altomare, F.; Berkley, A. J.; Bumble, B.; Bunyk, P.; Day, P. K.; Eom, B. H.; Harris, R.; Hilton, J. P.; Johnson, M. W.; Kleinsasser, A.; Ladizinsky, E.; Lanting, T.; Oh, T.; Perminov, I.; Tolkacheva, E.; Yao, J.

    Frequency multiplexed arrays of superconducting microresonators have been used as detectors in a variety of applications. The degree of multiplexing achievable is limited by fabrication variation causing non-uniform shifts in resonator frequencies. We have designed, implemented and characterized a superconducting microresonator readout that incorporates two tunable inductances per detector, allowing independent control of each detector frequency and sensitivity. The tunable inductances are adjusted using on-chip programmable digital-to-analog flux converters, which are programmed with a scalable addressing scheme that requires few external lines.

  2. Integration of a highly ordered gold nanowires array with glucose oxidase for ultra-sensitive glucose detection

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Jiewu [NanoScience and Sensor Technology Research Group, School of Applied Sciences and Engineering, Monash University, Gippsland Campus, Churchill 3842, VIC Australia (Australia); Laboratory of Functional Nanomaterials and Devices, School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, Anhui (China); Adeloju, Samuel B., E-mail: sam.adeloju@monash.edu [NanoScience and Sensor Technology Research Group, School of Applied Sciences and Engineering, Monash University, Gippsland Campus, Churchill 3842, VIC Australia (Australia); Wu, Yucheng, E-mail: ycwu@hfut.edu.cn [Laboratory of Functional Nanomaterials and Devices, School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, Anhui (China)

    2014-01-27

    Graphical abstract: -- Highlights: •Successfully synthesised highly-ordered gold nanowires array with an AAO template. •Fabricated an ultra-sensitive glucose nanobiosensor with the gold nanowires array. •Achieved sensitivity as high as 379.0 μA cm{sup −2} mM{sup −1} and detection limit as low as 50 nM. •Achieved excellent anti-interference with aid of Nafion membrane towards UA and AA. •Enabled successful detection and quantification of glucose in human blood serum. -- Abstract: A highly sensitive amperometric nanobiosensor has been developed by integration of glucose oxidase (GO{sub x}) with a gold nanowires array (AuNWA) by cross-linking with a mixture of glutaraldehyde (GLA) and bovine serum albumin (BSA). An initial investigation of the morphology of the synthesized AuNWA by field emission scanning electron microscopy (FESEM) and field emission transmission electron microscopy (FETEM) revealed that the nanowires array was highly ordered with rough surface, and the electrochemical features of the AuNWA with/without modification were also investigated. The integrated AuNWA–BSA–GLA–GO{sub x} nanobiosensor with Nafion membrane gave a very high sensitivity of 298.2 μA cm{sup −2} mM{sup −1} for amperometric detection of glucose, while also achieving a low detection limit of 0.1 μM, and a wide linear range of 5–6000 μM. Furthermore, the nanobiosensor exhibited excellent anti-interference ability towards uric acid (UA) and ascorbic acid (AA) with the aid of Nafion membrane, and the results obtained for the analysis of human blood serum indicated that the device is capable of glucose detection in real samples.

  3. Pulsed laser deposited Ag nanoparticles on nickel hydroxide nanosheet arrays for highly sensitive surface-enhanced Raman scattering spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jing, Yuting; Wang, Huanwen; Chen, Xiao [Department of Chemistry, Tongji University, Shanghai 200092 (China); Wang, Xuefeng, E-mail: xfwang@tongji.edu.cn [Department of Chemistry, Tongji University, Shanghai 200092 (China); Wei, Huige [Integrated Composites Laboratory (ICL), Dan F. Smith Department of Chemical Engineering, Lamar University, Beaumont, Texas 77710 (United States); Guo, Zhanhu, E-mail: zhanhu.guo@lamar.edu [Integrated Composites Laboratory (ICL), Dan F. Smith Department of Chemical Engineering, Lamar University, Beaumont, Texas 77710 (United States)

    2014-10-15

    Highlights: • Silver nanoparticles (NPs) were deposited on nickel hydroxide nanosheet (NS) arrays by pulsed laser deposition (PLD) for surface-enhanced Raman scattering (SERS) spectroscopy. • The Ag/Ni(OH){sub 2} composite film exhibits very high Raman scattering enhancement ability, possessing an enhancement factor as high as 5 × 10{sup 6}. • The enhancement ability of the substrate was strongly dependent on the size and interparticle gap of Ag NPs. • The 3D structure of Ni(OH){sub 2} NS arrays and the charge transfer of Ag NPs may be responsible for this high sensitivity Raman phenomenon. - Abstract: In the present work, silver nanoparticles (NPs) were deposited on nickel hydroxide nanosheet (NS) arrays by pulsed laser deposition (PLD) for surface-enhanced Raman scattering (SERS) spectroscopy. The effective high specific surface area with silver NPs decorated on the NS arrays was revealed by field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The microstructure and optical property of this three-dimensional (3D) substrate were investigated by X-ray diffraction (XRD) and UV–vis spectra, respectively. Using rhodamine 6G (R6G) as probe molecules with the concentration down to 10{sup −5} M, the Ag/Ni(OH){sub 2} composite film exhibits very high Raman scattering enhancement ability, possessing an enhancement factor as high as 5 × 10{sup 6}. It has been found that the enhancement ability of the substrate was strongly dependent on the size and interparticle gap of Ag NPs rather than the testing position on the film surface. In addition, the 3D structure of Ni(OH){sub 2} NS arrays and the charge transfer of Ag NPs may be responsible for this high sensitivity Raman phenomenon.

  4. Delta-doped CCDs as stable, high sensitivity, high resolution UV imaging arrays

    Energy Technology Data Exchange (ETDEWEB)

    Nikzad, S.; Hoenk, M.E.; Grunthaner, P.J.; Terhune, R.W.; Grunthaner, F.J. [California Inst. of Technology, Pasadena, CA (United States); Winzenread, R.; Fattahi, M.; Tseng, H.F. [EG and G Reticon, Sunnyvale, CA (United States)

    1994-12-31

    Delta-doped CCDs have achieved stable quantum efficiency, at the theoretical limit imposed by reflection from the Si surface in the near UV and visible. In this approach, an epitaxial silicon layer is grown on a fully-processed commercial CCD using molecular beam epitaxy. During the silicon growth on the CCD, 30% of a monolayer of boron atoms are deposited nominally within a single atomic layer, resulting in the effective elimination of the backside potential well. These devices are highly uniform and have exhibited long-term stability. To achieve significantly higher total quantum efficiency, antireflection layers can be directly deposited on the device. This was demonstrated in the 250--400 nm region.

  5. Array high-sensitivity room temperature coil system for SNMR detection in shallow depth

    Science.gov (United States)

    Lin, Tingting; Xie, Kunyu; Zhang, Siyuan; Zhao, Jing; Lin, Jun

    2017-01-01

    The noninvasive method of surface nuclear magnetic resonance (SNMR) is a geophysical technique that is directly sensitive to hydrogen protons, besides it can exploit the NMR phenomenon for a quantitative determination of the subsurface groundwater distribution. Traditionally, SNMR utilizes large surface coils for both transmitting excitation pulses and recording the groundwater response. While, in recent research, a low Tc-SQUIDs is taken as a new sensor to replace the large receiving coil (Rx), which performing the best sensitivity for the shallow depth. Nevertheless, SQUID is with the problems of flux trapping and operational difficulties. In this paper, we introduce a room temperature coil system. A Cu coil with diameter of 1 m and a low noise preamplifier was systematically investigated and reached a sensitivity of 0.2fT/Hz1/2.Four preamplifiers are chosen for optimizing the pickup coils. The resolution studies for the array coil systems were performed, and the optimum distance between the adjacent pickup coils to achieve a better experimental results especially for the shallow depth. Our study enable the further use of the room temperature coil for SNMR shallow depth detections.

  6. Design of crossing metallic metasurface arrays based on high sensitivity of gap enhancement and transmittance shift for plasmonic sensing applications

    Science.gov (United States)

    Chou Chau, Yuan-Fong; Syu, Jhih-Yu; Chou Chao, Chung-Ting; Chiang, Hai-Pang; Lim, Chee Ming

    2017-02-01

    We have systematically investigated a general approach to optimize the optical performances of a 2D array of crossing metal nanoparticle (MNP) thin film. These functionalized metasurface MNPs are designed for use as wavelength-selection filters in high-sensitivity infrared spectroscopic plasmonic sensors. The effects of different structural parameters corresponding to the gap-enhancement and bonded transmittance modes on MNP arrays are studied. Two types of sensor configurations based on gold MNP arrays are thoroughly investigated by using the finite element method. The calculated transmittance spectra of the proposed metasurfaces demonstrate near-infrared transmittance dips with a sensitivity range of 120-700 nm RIU-1 in a dielectric constant (ɛ) ranging from 1.0-3.0. We illustrate that it is possible to increase their sensitivity in the detection of chemical and biological substances. The proposed metasurfaces supporting both core-medium sensitivity and bonded-mode resonances are desirable for label-free sensing applications.

  7. An innovative, highly sensitive receiver system for the Square Kilometre Array Mid Radio Telescope

    Science.gov (United States)

    Tan, Gie Han; Lehmensiek, Robert; Billade, Bhushan; Caputa, Krzysztof; Gauffre, Stéphane; Theron, Isak P.; Pantaleev, Miroslav; Ljusic, Zoran; Quertier, Benjamin; Peens-Hough, Adriaan

    2016-07-01

    The Square Kilometre Array (SKA) Project is a global science and engineering project realizing the next-generation radio telescopes operating in the metre and centimetre wavelengths regions. This paper addresses design concepts of the broadband, exceptionally sensitive receivers and reflector antennas deployed in the SKA1-Mid radio telescope to be located in South Africa. SKA1-Mid (350 MHz - 13.8 GHz with an option for an upper limit of 24 GHz) will consist of 133 reflector antennas using an unblocked aperture, offset Gregorian configuration with an effective diameter of 15 m. Details on the unblocked aperture Gregorian antennas, low noise front ends and advanced direct digitization receivers, are provided from a system design perspective. The unblocked aperture results in increased aperture efficiency and lower side-lobe levels compared to a traditional on-axis configuration. The low side-lobe level reduces the noise contribution due to ground pick-up but also makes the antenna less susceptible to ground-based RFI sources. The addition of extra shielding on the sub-reflector provides a further reduction of ground pick-up. The optical design of the SKA1-Mid reflector antenna has been tweaked using advanced EM simulation tools in combination with sophisticated models for sky, atmospheric and ground noise contributions. This optimal antenna design in combination with very low noise, partially cryogenic, receivers and wide instantaneous bandwidth provide excellent receiving sensitivity in combination with instrumental flexibility to accommodate a wide range of astronomical observation modes.

  8. A frequency and sensitivity tunable microresonator array for high-speed quantum processor readout

    CERN Document Server

    Whittaker, J D; Volkmann, M H; Spear, P; Altomare, F; Berkley, A J; Bumble, B; Bunyk, P; Day, P K; Eom, B H; Harris, R; Hilton, J P; Hoskinson, E; Johnson, M W; Kleinsasser, A; Ladizinsky, E; Lanting, T; Oh, T; Perminov, I; Tolkacheva, E; Yao, J

    2015-01-01

    Superconducting microresonators have been successfully utilized as detection elements for a wide variety of applications. With multiplexing factors exceeding 1,000 detectors per transmission line, they are the most scalable low-temperature detector technology demonstrated to date. For high-throughput applications, fewer detectors can be coupled to a single wire but utilize a larger per-detector bandwidth. For all existing designs, fluctuations in fabrication tolerances result in a non-uniform shift in resonance frequency and sensitivity, which ultimately limits the efficiency of band-width utilization. Here we present the design, implementation, and initial characterization of a superconducting microresonator readout integrating two tunable inductances per detector. We demonstrate that these tuning elements provide independent control of both the detector frequency and sensitivity, allowing us to maximize the transmission line bandwidth utilization. Finally we discuss the integration of these detectors in a m...

  9. Towards the development of a high-sensitivity cryogenic phased array feed

    Science.gov (United States)

    Roshi, D. A.; Warnick, K. F.; Brandt, J.; Fisher, J. R.; Ford, P.; Jeffs, B. D.; Marganian, P.; McLeod, M.; Mello, M.; Morgan, M.; Norrod, R.; Shillue, W.; Simon, R.; White, S.

    2014-08-01

    A cryogenic phased array feed operating at L-band is in development for the Green Bank Telescope (GBT). The feed consists of electrically small feed elements optimized for active impedance matching to cooled front end low noise amplifiers (LNAs), down-converters, a real-time streaming data acquisition system, and beamforming algorithms applied in post-processing. A prototype cryogenic array feed was recently tested on the GBT. This results will be an important step towards the development of a new receiver instrument, the focal L-band array for the GBT (FLAG).

  10. A versatile method to grow localized arrays of nanowires for highly sensitive capacitive devices

    DEFF Research Database (Denmark)

    Antohe, V.A.; Radu, A.; Yunus, S.

    2008-01-01

    We propose a new approach to increase the detection efficiency of the capacitive sensing devices, by growing vertically aligned nanowires arrays, localized and confined on small interdigited electrodes structures. The metallic tracks are made using optical lithography, and the nanowires are reali......We propose a new approach to increase the detection efficiency of the capacitive sensing devices, by growing vertically aligned nanowires arrays, localized and confined on small interdigited electrodes structures. The metallic tracks are made using optical lithography, and the nanowires...

  11. A frequency and sensitivity tunable microresonator array for high-speed quantum processor readout

    Energy Technology Data Exchange (ETDEWEB)

    Whittaker, J. D., E-mail: jwhittaker@dwavesys.com; Swenson, L. J.; Volkmann, M. H.; Spear, P.; Altomare, F.; Berkley, A. J.; Bunyk, P.; Harris, R.; Hilton, J. P.; Hoskinson, E.; Johnson, M. W.; Ladizinsky, E.; Lanting, T.; Oh, T.; Perminov, I.; Tolkacheva, E.; Yao, J. [D-Wave Systems, Inc., Burnaby, British Columbia V5G 4M9 (Canada); Bumble, B.; Day, P. K.; Eom, B. H. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States); and others

    2016-01-07

    Superconducting microresonators have been successfully utilized as detection elements for a wide variety of applications. With multiplexing factors exceeding 1000 detectors per transmission line, they are the most scalable low-temperature detector technology demonstrated to date. For high-throughput applications, fewer detectors can be coupled to a single wire but utilize a larger per-detector bandwidth. For all existing designs, fluctuations in fabrication tolerances result in a non-uniform shift in resonance frequency and sensitivity, which ultimately limits the efficiency of bandwidth utilization. Here, we present the design, implementation, and initial characterization of a superconducting microresonator readout integrating two tunable inductances per detector. We demonstrate that these tuning elements provide independent control of both the detector frequency and sensitivity, allowing us to maximize the transmission line bandwidth utilization. Finally, we discuss the integration of these detectors in a multilayer fabrication stack for high-speed readout of the D-Wave quantum processor, highlighting the use of control and routing circuitry composed of single-flux-quantum loops to minimize the number of control wires at the lowest temperature stage.

  12. Implementation of an Optical Readout System for High-Sensitivity Terahertz Microelectromechanical Sensor Array

    Science.gov (United States)

    2014-09-01

    applications, it has been reported that Golay cell micro arrays based on a graphene membrane have been developed with a responsivity of 400 nm/K [26...vol. 37, pp. 1886‒1888, Jun. 2012. [8] F. Alves, B. Kearney, D. Grbovic, N. V. Lavrik, and G. Karunasiri, “Strong terahertz absorption using SiO2 /Al...49. [26] E. Ledwosinska, A. Guermoune, M. Siaj, and T. Szkopek, “Fabrication and characterization of suspended graphene membranes for miniature

  13. The Xsense project: The application of an intelligent sensor array for high sensitivity handheld explosives detectors

    DEFF Research Database (Denmark)

    Kostesha, Natalie; Schmidt, Michael Stenbæk; Bosco, Filippo

    2011-01-01

    of identifying concentrations of TNT, DNT, HMX and RDX at sub parts-per-billion (ppb) levels and with a false positive rate less than 1 parts-per-thousand. The specificity, sensitivity, reliability and the speed of responses are ensured by the use of advanced data processing, surface functionalization...

  14. Individually addressable microelectrode arrays fabricated with gold-coated pencil graphite particles for multiplexed and high sensitive impedance immunoassays.

    Science.gov (United States)

    Zhang, Yun; Wang, Hua; Nie, Jinfang; Zhang, Yuwei; Shen, Guoli; Yu, Ruqin

    2009-09-15

    A renewable, site-selective immobilization platform of microelectrode array (MEA) for multiplexed immunoassays has been initially developed using pencil graphite particles coated with gold layers as microelectrodes. The graphite particles available on the common pencil were utilized for directing the electro-deposition of gold layers with uniform microstructures which displayed a well-defined sigmoidal voltammetric response. In the concept-of-proof experiments, the resulting MEA platform was modified with functionalized monolayer, on which anti-human IgG antibodies could be stably immobilized in a site-selective way through binding chemistry to selectively capture human IgG antigens from the sample media. The subsequent introduction of anti-human IgG antibodies conjugated with 15 nm electro-active gold nanoparticles to recognize the captured IgG proteins resulted in a significant decrease in the interfacial electron-transfer resistance. High sensitive electrochemical quantification by gold nanoparticle-amplified impedance responses could thus be achieved. Experimental results show that the developed MEA sensor can allow for the detection of human IgG with wide linear range (0.05-100 ng ml(-1)) and sensitivity over 10(3) larger than that of the conventional, bulk gold electrode. The rapid regeneration of the used MEA platform can additionally be realized by a simple electrochemical treatment. The high selectivity of four individually addressable MEA platforms for multiple antigens in a single sample has been further demonstrated in the multiplexed immunoassay experiments. Such a site-selective immobilization strategy of MEA platform may open a new door towards the development of various simple, sensitive, cost-effective, and reusable biological sensors and biochips.

  15. TiO2 Nanotube Arrays Composite Film as Photoanode for High-Efficiency Dye-Sensitized Solar Cell

    Directory of Open Access Journals (Sweden)

    Jinghua Hu

    2014-01-01

    Full Text Available A double-layered photoanode made of hierarchical TiO2 nanotube arrays (TNT-arrays as the overlayer and commercial-grade TiO2 nanoparticles (P25 as the underlayer is designed for dye-sensitized solar cells (DSSCs. Crystallized free-standing TNT-arrays films are prepared by two-step anodization process. For photovoltaic applications, DSSCs based on double-layered photoanodes produce a remarkably enhanced power conversion efficiency (PCE of up to 6.32% compared with the DSSCs solely composed of TNT-arrays (5.18% or nanoparticles (3.65% with a similar thickness (24 μm at a constant irradiation of 100 mW cm−2. This is mainly attributed to the fast charge transport paths and superior light-scattering ability of TNT-arrays overlayer and good electronic contact with F-doped tin oxide (FTO glass provided from P25 nanoparticles as a bonding layer.

  16. A novel lab-on-chip platform with integrated solid phase PCR and Supercritical Angle Fluorescence (SAF) microlens array for highly sensitive and multiplexed pathogen detection.

    Science.gov (United States)

    Hung, Tran Quang; Chin, Wai Hoe; Sun, Yi; Wolff, Anders; Bang, Dang Duong

    2017-04-15

    Solid-phase PCR (SP-PCR) has become increasingly popular for molecular diagnosis and there have been a few attempts to incorporate SP-PCR into lab-on-a-chip (LOC) devices. However, their applicability for on-line diagnosis is hindered by the lack of sensitive and portable on-chip optical detection technology. In this paper, we addressed this challenge by combining the SP-PCR with super critical angle fluorescence (SAF) microlens array embedded in a microchip. We fabricated miniaturized SAF microlens array as part of a microfluidic chamber in thermoplastic material and performed multiplexed SP-PCR directly on top of the SAF microlens array. Attribute to the high fluorescence collection efficiency of the SAF microlens array, the SP-PCR assay on the LOC platform demonstrated a high sensitivity of 1.6 copies/µL, comparable to off-chip detection using conventional laser scanner. The combination of SP-PCR and SAF microlens array allows for on-chip highly sensitive and multiplexed pathogen detection with low-cost and compact optical components. The LOC platform would be widely used as a high-throughput biosensor to analyze food, clinical and environmental samples.

  17. Silicon on-chip side-coupled high-Q micro-cavities for the multiplexing of high sensitivity photonic crystal integrated sensors array

    Science.gov (United States)

    Yang, Daquan; Wang, Chunhong; Yuan, Wei; Wang, Bo; Yang, Yujie; Ji, Yuefeng

    2016-09-01

    A novel two-dimensional (2D) silicon (Si) photonic crystal (PC) α-H0-slot micro-cavity with high Q-factor and high sensitivity (S) is presented. Based on the proposed α-H0-Slot micro-cavities, an optimal design of photonic crystal integrated sensors array (PC-ISA) on monolithic silicon on insulator (SOI) is displayed. By using finite-difference time-domain (FDTD) method, the simulation results demonstrate that both large S of 200 nm/RIU (RIU=refractive index unit) and high Q-factor >104 at telecom wavelength range can be achieved simultaneously. And the sensor figure of merit (FOM)>7000 is featured, an order of magnitude improvement over previous 2D PC sensors array. In addition, for the proposed 2D PC-ISA device, each sensor unit is shown to independently shift its resonance wavelength in response to the changes in refractive index (RI) and does not perturb the others. Thus, it is potentially an ideal platform for realizing ultra-compact lab-on-a-chip applications with dense arrays of functionalized spots for multiplexed sensing, and also can be used as an opto-fluidic architecture for performing highly parallel detection of biochemical interactions in aqueous environments.

  18. Progress Towards High-Sensitivity Arrays of Detectors of Sub-mm Radiation Using Superconducting Tunnel Junctions with Integrated Radio Frequency Single-Electron Transistors

    Science.gov (United States)

    Stevenson, T. R.; Hsieh, W.-T.; Li, M. J.; Prober, D. E.; Rhee, K. W.; Schoelkopf, R. J.; Stahle, C. M.; Teufel, J.; Wollack, E. J.

    2004-01-01

    For high resolution imaging and spectroscopy in the FIR and submillimeter, space observatories will demand sensitive, fast, compact, low-power detector arrays with 104 pixels and sensitivity less than 10(exp -20) W/Hz(sup 0.5). Antenna-coupled superconducting tunnel junctions with integrated rf single-electron transistor readout amplifiers have the potential for achieving this high level of sensitivity, and can take advantage of an rf multiplexing technique. The device consists of an antenna to couple radiation into a small superconducting volume and cause quasiparticle excitations, and a single-electron transistor to measure current through junctions contacting the absorber. We describe optimization of device parameters, and results on fabrication techniques for producing devices with high yield for detector arrays. We also present modeling of expected saturation power levels, antenna coupling, and rf multiplexing schemes.

  19. A Sensitive and Biodegradable Pressure Sensor Array for Cardiovascular Monitoring.

    Science.gov (United States)

    Boutry, Clementine M; Nguyen, Amanda; Lawal, Qudus Omotayo; Chortos, Alex; Rondeau-Gagné, Simon; Bao, Zhenan

    2015-11-18

    An array of highly sensitive pressure sensors entirely made of biodegradable materials is presented, designed as a single-use flexible patch for application in cardiovascular monitoring. The high sensitivity in combination with fast response time is unprecedented when compared to recent reports on biodegradable pressure sensors (sensitivity three orders of magnitude higher), as illustrated by pulse wave velocity measurements, toward hypertension detection.

  20. Progress Towards High-Sensitivity Arrays of Detectors of Sub-mm Radiation using Superconducting Tunnel Junctions with Radio-Frequency Single-Electron Transistors

    Science.gov (United States)

    Stevenson, T. R.; Hsieh, W.-T.; Li, M. J.; Stahle, C. M.; Wollack, E. J.; Schoelkopf, R. J.; Krebs, Carolyn (Technical Monitor)

    2002-01-01

    The science drivers for the SPIRIT/SPECS missions demand sensitive, fast, compact, low-power, large-format detector arrays for high resolution imaging and spectroscopy in the far infrared and submillimeter. Detector arrays with 10,000 pixels and sensitivity less than 10(exp 20)-20 W/Hz(exp 20)0.5 are needed. Antenna-coupled superconducting tunnel junction detectors with integrated rf single-electron transistor readout amplifiers have the potential for achieving this high level of sensitivity, and can take advantage of an rf multiplexing technique when forming arrays. The device consists of an antenna structure to couple radiation into a small superconducting volume and cause quasiparticle excitations, and a single-electron transistor to measure currents through tunnel junction contacts to the absorber volume. We will describe optimization of device parameters, and recent results on fabrication techniques for producing devices with high yield for detector arrays. We will also present modeling of expected saturation power levels, antenna coupling, and rf multiplexing schemes.

  1. Highly sensitive photodetection using a microwave-coupled BaPb0.7Bi0.3O3 Josephson junction array

    Science.gov (United States)

    Ito, Minoru; Enomoto, Youichi; Murakami, Toshiaki

    1983-08-01

    The BaPb0.7Bi0.3O3 sputtered film possesses tunnel Josephson junctions at boundary layers [boundary Josephson junction (BJJ)] normal to the film plane in a homogeneous junction array. The film has high efficiency for optical irradiation of the junctions because of the high optical transparency. The letter presents the optical effect on the current-voltage characteristics for this Josephson junction array locked to a microwave field. The microwave-induced hysteresis loop caused by voltage locking among junctions in a microwave field is highly sensitive to optical illumination with as low an incident power as a few nanowatts. This probably can be exploited in a future, highly sensitive photodetector.

  2. Increase in the Array Television Camera Sensitivity

    Science.gov (United States)

    Shakhrukhanov, O. S.

    A simple adder circuit for successive television frames that enables to considerably increase the sensitivity of such radiation detectors is suggested by the example of array television camera QN902K.

  3. HEB heterodyne focal plane arrays: a terahertz technology for high sensitivity near-range security imaging systems

    Science.gov (United States)

    Gerecht, Eyal; Gu, Dazhen; Yngvesson, Sigfrid; Rodriguez-Morales, Fernando; Zannoni, R.; Nicholson, John

    2005-05-01

    We have achieved the first demonstration of a low-noise heterodyne array operating at a frequency above 1 THz (1.6 THz). The prototype array has three elements, consisting of NbN hot electron bolometer (HEB) detectors on silicon substrates. We use a quasi-optical design to couple the signal and local oscillator (LO) power to the detector. We also demonstrate, for the first time, how the HEB detectors can be intimately integrated in the same block with monolithic microwave integrated circuit (MMIC) IF amplifiers. Such focal plane arrays can be increased in size to a few hundred elements using the next generation fabrication architecture for compact and easy assembly. Future HEB-based focal plane arrays will make low-noise heterodyne imaging systems with high angular resolution possible from 500 GHz to several terahertz. Large low-noise HEB arrays are well suited for real-time video imaging at any frequency over the entire terahertz spectrum. This is made possible by virtue of the extremely low local oscillator power requirements of the HEB detectors (a few hundred nanowatts to a microwatt per pixel). The operating temperature is 4 to 6 K, which can be provided by a compact and mobile cryocooler system, developed as a spin-off from the space program. The terahertz HEB imager consists of a computer-controlled optical system mounted on an elevation and azimuth scanning translator which provides a two-dimensional image of the target. We present preliminary measured data at the symposium for a terahertz security system of this type.

  4. Morphology-controlled cactus-like branched anatase TiO2 arrays with high light-harvesting efficiency for dye-sensitized solar cells

    Science.gov (United States)

    Wu, Wu-Qiang; Rao, Hua-Shang; Feng, Hao-Lin; Guo, Xin-Dong; Su, Cheng-Yong; Kuang, Dai-Bin

    2014-08-01

    The present work establishes a facile process for one-step hydrothermal growth of vertically aligned anatase cactus-like branched TiO2 (CBT) arrays on a transparent conducting oxide (TCO) substrate. Various CBT morphologies are obtained by adjusting the potassium titanium oxide oxalate (PTO) reactant concentration (from 0.05 M to 0.15 M) and this yields a morphologically-controllable branched TiO2 arrays geometry. The CBT arrays consist of a vertically oriented nanowire (NW) or nanosheet (NS) stem and a host of short nanorod (NR) branches. The hierarchical CBT arrays demonstrate their excellent candidatures as photoanodes, which are capable of exhibiting high light-harvesting efficiency in dye-sensitized solar cells (DSSCs). Consequently, DSSCs based on 7 μm long optimized CBT arrays (0.05 M PTO), which are assembled with high density and high aspect-ratio NR branches, exhibit an impressive power conversion efficiency of 6.43% under AM 1.5G one sun illumination. The high performance can be attributed to the prominent light-harvesting efficiency, resulting from larger surface area and superior light-scattering capability.

  5. A novel lab-on-chip platform with integrated solid phase PCR and Supercritical Angle Fluorescence (SAF) microlens array for highly sensitive and multiplexed pathogen detection

    DEFF Research Database (Denmark)

    Hung, Tran Quang; Chin, Wai Hoe; Sun, Yi

    2016-01-01

    Solid-phase PCR (SP-PCR) has become increasingly popular for molecular diagnosis and there have been a few attempts to incorporate SP-PCR into lab-on-a-chip (LOC) devices. However, their applicability for on-line diagnosis is hindered by the lack of sensitive and portable on-chip optical detectio......-PCR and SAF microlens array allows for on-chip highly sensitive and multiplexed pathogen detection with low-cost and compact optical components. The LOC platform would be widely used as a high-throughput biosensor to analyze food, clinical and environmental samples....

  6. Using genomic DNA-based probe-selection to improve the sensitivity of high-density oligonucleotide arrays when applied to heterologous species

    Directory of Open Access Journals (Sweden)

    Townsend Henrik J

    2005-11-01

    Full Text Available Abstract High-density oligonucleotide (oligo arrays are a powerful tool for transcript profiling. Arrays based on GeneChip® technology are amongst the most widely used, although GeneChip® arrays are currently available for only a small number of plant and animal species. Thus, we have developed a method to improve the sensitivity of high-density oligonucleotide arrays when applied to heterologous species and tested the method by analysing the transcriptome of Brassica oleracea L., a species for which no GeneChip® array is available, using a GeneChip® array designed for Arabidopsis thaliana (L. Heynh. Genomic DNA from B. oleracea was labelled and hybridised to the ATH1-121501 GeneChip® array. Arabidopsis thaliana probe-pairs that hybridised to the B. oleracea genomic DNA on the basis of the perfect-match (PM probe signal were then selected for subsequent B. oleracea transcriptome analysis using a .cel file parser script to generate probe mask files. The transcriptional response of B. oleracea to a mineral nutrient (phosphorus; P stress was quantified using probe mask files generated for a wide range of gDNA hybridisation intensity thresholds. An example probe mask file generated with a gDNA hybridisation intensity threshold of 400 removed > 68 % of the available PM probes from the analysis but retained >96 % of available A. thaliana probe-sets. Ninety-nine of these genes were then identified as significantly regulated under P stress in B. oleracea, including the homologues of P stress responsive genes in A. thaliana. Increasing the gDNA hybridisation intensity thresholds up to 500 for probe-selection increased the sensitivity of the GeneChip® array to detect regulation of gene expression in B. oleracea under P stress by up to 13-fold. Our open-source software to create probe mask files is freely available http://affymetrix.arabidopsis.info/xspecies/ and may be used to facilitate transcriptomic analyses of a wide range of plant and animal

  7. Highly-ordered TiO{sub 2} nanotube arrays up to 220 {mu}m in length: use in water photoelectrolysis and dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Shankar, Karthik [Department of Electrical Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Mor, Gopal K [Materials Research Institute, Pennsylvania State University, University Park, PA 16802 (United States); Prakasam, Haripriya E [Department of Electrical Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Yoriya, Sorachon [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Paulose, Maggie [Materials Research Institute, Pennsylvania State University, University Park, PA 16802 (United States); Varghese, Oomman K [Materials Research Institute, Pennsylvania State University, University Park, PA 16802 (United States); Grimes, Craig A [Department of Electrical Engineering, Pennsylvania State University, University Park, PA 16802 (United States)

    2007-02-14

    The fabrication of highly-ordered TiO{sub 2} nanotube arrays up to 134 {mu}m in length by anodization of Ti foil has recently been reported (Paulose et al 2006 J. Phys. Chem. B 110 16179). This work reports an extension of the fabrication technique to achieve TiO{sub 2} nanotube arrays up to 220 {mu}m in length, with a length-to-outer diameter aspect ratio of {approx}1400, as well as their initial application in dye-sensitized solar cells and hydrogen production by water photoelectrolysis. The highly-ordered TiO{sub 2} nanotube arrays are fabricated by potentiostatic anodization of Ti foil in fluoride ion containing baths in combination with non-aqueous organic polar electrolytes including N-methylformamide, dimethyl sulfoxide, formamide, or ethylene glycol. Depending upon the anodization voltage, the inner pore diameters of the resulting nanotube arrays range from 20 to 150 nm. As confirmed by glancing angle x-ray diffraction and HRTEM studies, the as-prepared nanotubes are amorphous but crystallize with annealing at elevated temperatures.

  8. Computer-aided strategies for archive retrieval and sensitivity enhancement in the identification of drugs by photodiode array detection in high-performance liquid chromatography.

    Science.gov (United States)

    Fell, A F; Clark, B J; Scott, H P

    1984-12-21

    An archive retrieval algorithm for high-performance liquid chromatography with UV detection (HPLC-UV) has been developed for the first time for the rapid identification of spectra acquired by rapid-scanning photodiode array detection in HPLC. The algorithm is based on a database of spectra (normalised with respect to area), inverse files of key spectral features, a selective search window, with parabolic weighting factors and least-squares comparison of test and retrieved spectra. The performance of the library search system is demonstrated with respect to a small library of solutes, including: cortisone acetate, ethynyl estradiol, ethisterone, progesterone; caffeine, theobromine, theophylline and 8-chlorotheophylline; morphine and diamorphine; and cycloserine. Since photodiode array detection operates in the domains of both wavelength and time, to generate a matrix of (A, lambda, t) data, the optimum conditions for sensitivity enhancement by ensemble averaging in these domains have been examined. At a given observation wavelength, increase in the detector bandwidth (or "diode bunching") yields a value of delta lambda which gives optimum sensitivity; this value is systematically related to the spectral bandwidth of the analyte. Sensitivity can also be optimised by varying the integration period in the time domain. Sensitivity can be further increased by combination of these instrumental optima, for which there is evidence of dependence on the particular instrument design. Response was found to be linear for detector bandwidths up to twice the optimum value. The comparative sensitivity of some commercially-available photodiode array detectors has been assessed relative to that of conventional detectors under strictly controlled conditions.

  9. A high-sensitivity magnetocardiography system with a divided gradiometer array inside a low boil-off Dewar

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y H; Yu, K K; Kim, J M; Kwon, H; Kim, K, E-mail: yhlee@kriss.re.k [Korea Research Institute of Standards and Science, 1 Doryong, Yuseong, Daejeon 305-600 (Korea, Republic of)

    2009-11-15

    We fabricated a low-noise 64-channel first-order axial gradiometer system for measuring magnetocardiography (MCG) signals. The key technical features of the system are the compact structure of the gradiometer, division of the sensor array plate, direct mounting of the sensor plates into the Dewar bottom, reduced neck diameter of the liquid He Dewar, and compact readout electronics. To make the refill interval of liquid He longer, the distance between the compensation coil of the gradiometer and the input coil pads of the superconducting quantum interference device (SQUID) was reduced to 20 mm. By using direct ultrasonic bonding of Nb wires between the pickup coil wires and input coil pads, the superconductive connection structure became simple. The baseline of the first-order gradiometer is 70 mm, a little longer than for typical conventional axial gradiometers, to provide a larger signal amplitude for deep sources. The 64-channel gradiometer array consists of four blocks, and each block is fixed separately onto the bottom of the Dewar. The neck diameter of the He Dewar (192 mm) is smaller than the bottom diameter (280 mm) in which the gradiometers are distributed. The average boil-off rate of the Dewar is 3 l per day when the 64-channel system is in operation every day. Double relaxation oscillation SQUIDs (DROSs) having large flux-to-voltage transfer coefficients were used to operate SQUIDs via compact electronics. The magnetically shielded room (MSR) has a wall thickness of 80 mm, and consists of two layers of permalloy and one layer of aluminum. When the 64-channel system was installed inside the MSR, the field noise level of the system was about 3.5 fT{sub rms} Hz{sup -1/2} at 100 Hz. MCG measurements with high signal quality were done successfully using the developed system. In addition to the parameter analysis method, we developed software for the three-dimensional imaging of the myocardial current on a realistic image of the heart based on the anatomical

  10. Pulsed laser deposition of Ag nanoparticles on titanium hydroxide/oxide nanobelt arrays for highly sensitive surface-enhanced Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jing, Yuting; Wang, Huanwen; Zhao, Jie; Yi, Huan; Wang, Xuefeng, E-mail: xfwang@tongji.edu.cn

    2015-08-30

    Highlights: • Silver nanoparticles (NPs) were deposited on Ti(OH){sub 4} nanobelt by pulsed laser deposition (PLD). • The highest enhancement factor of 10{sup 6} and a maximum relative standard deviation (RSD) of 0.18. • Ag{sub 2}O play important role for the high sensitivity Raman phenomenon. • Charge transfer from Ag NPs is also responsible for the enhancement ability. - Abstract: Surface-enhanced Raman scattering (SERS) substrate of Ti(OH){sub 4} nanobelt arrays (NBAs) was synthesized by a hydrothermal reaction, on which silver nanoparticles (NPs) were deposited by pulsed laser deposition (PLD). Field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) revealed the effective high specific surface area with silver NPs decorated on three-dimensional NBAs. Using rhodamine 6G (R6G) as an analyte molecule, the highest enhancement factor of 10{sup 6} and a maximum relative standard deviation (RSD) of 0.18 were obtained. It has been found that the specific morphology of these composite nanobelt arrays and the formation of Ag{sub 2}O play important role for the high sensitivity Raman phenomenon. In addition, the surface plasmon resonance wavelength of Ag decorated Ti(OH){sub 4} NBAs and the charge transfer from Ag NPs are also responsible for the enhancement ability. For comparison SERS was investigated with silver particles decorated on TiO{sub 2} NBAs, which is much less active.

  11. Sputtered highly ordered TiO2 nanorod arrays and their applications as the electrode in dye-sensitized solar cells.

    Science.gov (United States)

    Meng, Lijian; Ma, Aifeng; Ying, Pinliang; Feng, Zhaochi; Li, Can

    2011-02-01

    For the first time, the TiO2 nanorod arrays have been prepared on ITO substrates at room temperature by dc reactive magnetron sputtering technique. These TiO2 nanorods have a preferred orientation along the (220) direction and are perpendicular to the ITO substrate. Both the X-ray diffraction and Raman scattering measurements show that the highly ordered TiO2 nanorod arrays have an anatase crystal structure. The diameter of the nanorod varies from 30 nm to 100 nm and the nanorod length can be varied from several hundred nanometers to several micrometers depending on the deposition time. The TiO2 nanorod arrays with about 3 micrometers length have been used as an electrode for dye-sensitized solar cell (DSSC). Short-circuit photocurrent density, open-circuit voltage, fill factor and light-to-electricity conversion efficiency at 100 mW/cm2 light intensity are estimated to be 12.76 mA/cm2, 0.65 V, 0.63 and 5.25%, respectively, for the DSSC made of the TiO2 nanorods.

  12. High performance PbS quantum dot sensitized solar cells via electric field assisted in situ chemical deposition on modulated TiO2 nanotube arrays.

    Science.gov (United States)

    Tao, Liang; Xiong, Yan; Liu, Hong; Shen, Wenzhong

    2014-01-21

    Quantum dot sensitized solar cells (QDSSCs) are attractive photovoltaic devices due to their simplicity and low material requirements. However, efforts to realize high efficiencies in QDSSCs have often been offset by complicated processes and expensive or toxic materials, significantly limiting their useful application. In this work, we have realized for the first time, high performance PbS QDSSCs based on TiO2 nanotube arrays (NTAs) via an in situ chemical deposition method controlled by a low electric field. An efficiency, η, of ~3.41% under full sun illumination has been achieved, which is 133.6% higher than the best result previously reported for a simple system without doping or co-sensitizing, and comparable to systems with additional chemicals. Furthermore, a high open-circuit voltage (0.64 V), short-circuit current (8.48 mA cm(-2)) and fill factor (0.63) have been achieved. A great increase in the quantity of the loaded quantum dots (QDs) in the NTAs was obtained from the in situ electric field assisted chemical bath deposition (EACBD) process, which was the most significant contributing factor with respect to the high JSC. The high VOC and FF have been attributed to a much shorter electron path, less structural and electronic defects, and lower recombination in the ordered TiO2 NTAs produced by oscillating anodic voltage. Besides, the optimal film thickness (~4 μm) based on the NTAs was much thinner than that of the control cell based on nanoporous film (~30.0 μm). This investigation can hopefully offer an effective way of realizing high performance QDSSCs and QD growth/installation in other nanostructures as well.

  13. A highly sensitive room temperature H2S gas sensor based on SnO2 multi-tube arrays bio-templated from insect bristles.

    Science.gov (United States)

    Tian, Junlong; Pan, Feng; Xue, Ruiyang; Zhang, Wang; Fang, Xiaotian; Liu, Qinglei; Wang, Yuhua; Zhang, Zhijian; Zhang, Di

    2015-05-07

    A tin oxide multi-tube array (SMTA) with a parallel effect was fabricated through a simple and promising method combining chemosynthesis and biomimetic techniques; a biomimetic template was derived from the bristles on the wings of the Alpine Black Swallowtail butterfly (Papilio maackii). SnO2 tubes are hollow and porous structures with micro-pores regularly distributed on the wall. The morphology, the delicate microstructure and the crystal structure of this SMTA were characterized by super resolution digital microscopy, scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The SMTA exhibits a high sensitivity to H2S gas at room temperature. It also exhibits a short response/recovery time, with an average value of 14/30 s at 5 ppm. In particular, heating is not required for the SMTA in the gas sensitivity measurement process. On the basis of these results, SMTA is proposed as a suitable new material for the design and fabrication of room-temperature H2S gas sensors.

  14. Toward highly sensitive surface-enhanced Raman scattering: the design of a 3D hybrid system with monolayer graphene sandwiched between silver nanohole arrays and gold nanoparticles.

    Science.gov (United States)

    Zhao, Yuan; Yang, Dong; Li, Xiyu; Liu, Yu; Hu, Xiang; Zhou, Dianfa; Lu, Yalin

    2017-01-19

    We report a novel graphene-metal hybrid system by introducing monolayer graphene between gold nanoparticles (Au NPs) and silver nanohole (Ag NH) arrays. The design incorporates three key advantages to promote the surface-enhanced Raman scattering (SERS) sensing capacity: (i) making full use of the single-atomic feature of graphene for generating uniform sub-nanometer spaces; (ii) maintaining the bottom layer of Ag nanoarrays with an ordered manner for facilitating the transfer of graphene films and assembly of the top layer of Au NPs; (iii) integrating the advantages of the strong plasmonic effect of Ag, the chemical stability of Au, as well as the mechanical flexibility and biological compatibility of graphene. In this configuration, the plasmonic properties can be fine-tuned by separately optimizing the horizontal or vertical gaps between the metal NPs. Exactly, sub-20 nm spaces between the horizontally patterned Ag tips constructed by adjacent Ag NHs, and sub-nanometer scale graphene gaps between the vertically distributed Au NP-Ag NH have been achieved. Finite element numerical simulations demonstrate that the multi-dimensional plasmonic couplings (including the Au NP-Au NP, Au NP-Ag NH and Ag NH-Ag NH couplings) promote for the hybrid platform an electric field enhancement up to 137 times. Impressively, the as-prepared 3D Au NP-graphene-Ag NH array hybrid structure manifests ultrahigh SERS sensitivity with a detection limit of 10(-13) M for R6G molecules, as well as good reproducibility and stability. This work represents a step towards high-performance SERS substrate fabrication, and opens up a new route for graphene-plasmonic hybrids in SERS applications.

  15. Tunable, Highly Ordered TiO2 Nanotube Arrays on Indium Tin Oxide Coated PET for Flexible Bio-sensitized Solar Cells

    Science.gov (United States)

    2011-08-01

    free electron conduction pathway versus TiO2 nanoparticles in dye sensitized solar cell ( DSSC ) designs. TNT arrays prepared by electrochemical...Overview The classic DSSC is composed of a layer of nanocrystalline TiO2 particles on a conducting substrate, a platinum counter electrode, an...with the goal of optimizing key components of DSSCs , such as the TiO2 structures, the dye, and the electrolyte used. However, it is beyond the scope of

  16. High-Performance and Stable Gel-State Dye-Sensitized Solar Cells Using Anodic TiO2 Nanotube Arrays and Polymer-Based Gel Electrolytes.

    Science.gov (United States)

    Seidalilir, Zahra; Malekfar, Rasoul; Wu, Hui-Ping; Shiu, Jia-Wei; Diau, Eric Wei-Guang

    2015-06-17

    Highly ordered and vertically oriented TiO2 nanotube (NT) arrays were synthesized with potentiostatic anodization of Ti foil and applied to fabricate gel-state dye-sensitized solar cells (DSSCs). The open structure of the TiO2 NT facilitates the infiltration of the gel-state electrolyte; their one-dimensional structural feature provides effective charge transport. TiO2 NTs of length L=15-35 μm were produced on anodization for periods of t=5-15 h at a constant voltage of 60 V, and sensitized with N719 for photovoltaic characterization. A commercially available copolymer, poly(methyl methacrylate-co-ethyl acrylate) (PMMA-EA), served as a gelling agent to prepare a polymer-gel electrolyte (PGE) for DSSC applications. The PGE as prepared exhibited a maximum conductivity of 4.58 mS cm(-1) with PMMA-EA (7 wt %). The phase transition temperature (Tp) of the PGE containing PMMA-EA at varied concentrations was determined on the basis of the viscosities measured at varied temperatures. Tp increased with increasing concentration of PMMA-EA. An NT-DSSC with L=30 μm assembled using a PGE containing PMMA-EA (7 wt %) exhibited an overall power conversion efficiency (PCE) of 6.9%, which is comparable with that of a corresponding liquid-type device, PCE=7.1%. Moreover, the gel-state NT-DSSC exhibited excellent thermal and light-soaking enduring stability: the best device retained ∼90% of its initial efficiency after 1000 h under 1 sun of illumination at 50 °C, whereas its liquid-state counterpart decayed appreciably after light soaking for 500 h.

  17. “Turn-off” fluorescent data array sensor based on double quantum dots coupled with chemometrics for highly sensitive and selective detection of multicomponent pesticides

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Yao; Liu, Li; Sun, Donglei; Lan, Hanyue [The Modernization Engineering Technology Research Center of Ethnic Minority Medicine of Hubei Province, College of Pharmacy, South-Central University for Nationalities, Wuhan 430074 (China); Fu, Haiyan, E-mail: fuhaiyan@mail.scuec.edu.cn [The Modernization Engineering Technology Research Center of Ethnic Minority Medicine of Hubei Province, College of Pharmacy, South-Central University for Nationalities, Wuhan 430074 (China); Yang, Tianming, E-mail: tmyang@mail.scuec.edu.cn [The Modernization Engineering Technology Research Center of Ethnic Minority Medicine of Hubei Province, College of Pharmacy, South-Central University for Nationalities, Wuhan 430074 (China); She, Yuanbin, E-mail: sheyb@zjut.edu.cn [State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310032 (China); Ni, Chuang [The Modernization Engineering Technology Research Center of Ethnic Minority Medicine of Hubei Province, College of Pharmacy, South-Central University for Nationalities, Wuhan 430074 (China)

    2016-04-15

    As a popular detection model, the fluorescence “turn-off” sensor based on quantum dots (QDs) has already been successfully employed in the detections of many materials, especially in the researches on the interactions between pesticides. However, the previous studies are mainly focused on simple single track or the comparison based on similar concentration of drugs. In this work, a new detection method based on the fluorescence “turn-off” model with water-soluble ZnCdSe and CdSe QDs simultaneously as the fluorescent probes is established to detect various pesticides. The fluorescence of the two QDs can be quenched by different pesticides with varying degrees, which leads to the differences in positions and intensities of two peaks. By combining with chemometrics methods, all the pesticides can be qualitative and quantitative respectively even in real samples with the limit of detection was 2 × 10{sup −8} mol L{sup −1} and a recognition rate of 100%. This work is, to the best of our knowledge, the first report on the detection of pesticides based on the fluorescence quenching phenomenon of double quantum dots combined with chemometrics methods. What's more, the excellent selectivity of the system has been verified in different mediums such as mixed ion disruption, waste water, tea and water extraction liquid drugs. - Highlights: • A new model based on double QDs is established for pesticide residues detection. • The fluorescent data array sensor is coupled with chmometrics methods. • The sensor can be highly sensitive and selective detection in actual samples.

  18. Practical Considerations for Optimizing Position Sensitivity in Arrays of Position-sensitive TES's

    Science.gov (United States)

    Smith, Stephen J.; Bandler, Simon R.; Figueroa-Feliciano, Encetali; Iyomoto, Naoko; Kelley, Richard L.; Kilbourne, Caroline A.; Porder, Frederick S.; Sadleir, John E.

    2007-01-01

    We are developing Position-Sensitive Transitions-Edge Sensors (PoST's) for future X-ray astronomy missions such as NASA's Constellation-X. The PoST consists of one or more Transitions Edge Sensors (TES's) thermally connected to a large X-ray absorber, which through heat diffusion, gives rise to position dependence. The development of PoST's is motivated by the desire to achieve the largest the focal-plan coverage with the fewest number of readout channels. In order to develop a practical array, consisting of an inner pixellated core with an outer array of large absorber PoST's, we must be able to simultaneously read out all (-1800) channels in the array. This is achievable using time division multiplexing (TDM), but does set stringent slew rate requirements on the array. Typically, we must damp the pulses to reduce the slew rate of the input signal to the TDM. This is achieved by applying a low-pass analog filter with large inductance to the signal. This attenuates the high frequency components of the signal, essential for position discrimination in PoST's, relative to the white noise of the readout chain and degrades the position sensitivity. Using numerically simulated data, we investigate the position sensing ability of typical PoST designs under such high inductance conditions. We investigate signal-processing techniques for optimal determination of the event position and discuss the practical considerations for real-time implementation.

  19. High voltage load resistor array

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, Monty Ray [Smithfield, VA

    2005-01-18

    A high voltage resistor comprising an array of a plurality of parallel electrically connected resistor elements each containing a resistive solution, attached at each end thereof to an end plate, and about the circumference of each of the end plates, a corona reduction ring. Each of the resistor elements comprises an insulating tube having an electrode inserted into each end thereof and held in position by one or more hose clamps about the outer periphery of the insulating tube. According to a preferred embodiment, the electrode is fabricated from stainless steel and has a mushroom shape at one end, that inserted into the tube, and a flat end for engagement with the end plates that provides connection of the resistor array and with a load.

  20. 宽带高灵敏度柔性相控阵探头的发展与应用%Development and Application of Broadband High Sensitive Flexible Phased Array Probe

    Institute of Scientific and Technical Information of China (English)

    常俊杰; 魏强; 小倉幸夫; 卢超; 陈果

    2016-01-01

    超声相控阵技术因为检测效率高和灵敏度高等优势而常应用于工程实践中,但对于一些复杂表面材料的检测,常规相控阵探头不能与材料紧密贴合而导致检测困难.介绍了一种可以通过接触法检测材料的不规则表面和倒角处的柔性相控阵探头,并对其性能进行改进,提出了一种新的柔性相控阵探头.对新旧柔性相控阵探头的性能进行比较,表明了新的柔性探头具有高灵敏度和高分辨率(可达0.1 mm).最后,列举了新柔性相控阵探头在实际工程中的应用.%Ultrasonic phased array technology is often used in engineering application for high detection efficiency and high sensitivity.But for the detection of complex surface material,since the conventional phased array probe can not fit closely with the material it is therefore difficult for one to detect the material.This paper describes a flexible phased array probe that is available for detection of irregular surface & corner part of the specimen by direct contact method,and furthermore through improving the performance of the flexible phased array probe a new flexible phased array probe was developed.Through the performance comparison with the old flexible phased array probe,it is demonstrated that the new flexible phased array probe possesses high sensitivity and high resolution of 0.1 mm. Several practical engineering applications of the new flexible phased array probe are presented.The more engineering application of flexible phased array probe is expected.

  1. High performance of Mn-doped CdSe quantum dot sensitized solar cells based on the vertical ZnO nanorod arrays

    Science.gov (United States)

    Hou, Juan; Zhao, Haifeng; Huang, Fei; Jing, Qun; Cao, Haibin; Wu, Qiang; Peng, Shanglong; Cao, Guozhong

    2016-09-01

    Doping transition metal ions Mn2+ to semiconductor quantum dots (QDs) are extremely interesting for the development of photovoltaic devices. Quantum dot sensitized solar cells (QDSCs) are able to show promising power conversion efficiencies (PCE) by employing Mn2+ doped QDs. Herein we achieve effective CdS/Mnsbnd CdSe/ZnS QDs co-sensitized vertical ZnO nanorod arrays film that provides an appreciable enhancement in photovoltaic performance. The measured PCE of the solar cells with Mn2+ doped CdSe QDs is 4.14%, which is higher than the efficiency of 2.91% for the solar cells without Mn2+ or a ∼42% increase. The improvement in PCE is ascribed to a higher open-circuit voltage (Voc = 0.74 V) and a superior short-circuit current density (Jsc = 12.6 mA cm-2) with the introduction of Mn2+ into CdSe QDs. The enhancement seen with Mn2+ doped CdSe QDs are investigated and explained by the fact that the enhanced light absorption and reduced charge recombination by the formation of Mnsbnd CdSe passivation layer covering the QDs.

  2. TiO2 nanotube arrays and TiO2-nanotube-array based dye-sensitized solar Cell

    Institute of Scientific and Technical Information of China (English)

    LIU YanBiao; ZHOU BaoXue; XIONG BiTao; BAI Jing; LI LongHai

    2007-01-01

    To substitute the non-regular nano-crystalline semiconductor for a novel kind of ordered microstructure is a very important aspect in the domain of dye-sensitized solar cell.One of the researching hotspots is the highly-ordered TiO2 nanotube architecture.As a new type of titania nano-material,titania nanotube arrays have drawn extraordinary attention due to its distinctive morphology,notable photoelectrical and hydro-sensitive performance.At 100% sun the new kind of TiO2 nanotube arrays solar cell exhibits an overall conversion efficiency of 5.44%.This paper introduces the preparation methods of titania nanotube arrays,the existing problems and recent progress in titania nanotube arrays solar cell.

  3. Design, theoretical analysis, and experimental verification of a CMOS current integrator with 1.2 × 2.05 µm2 microelectrode array for high-sensitivity bacterial counting

    Science.gov (United States)

    Gamo, Kohei; Nakazato, Kazuo; Niitsu, Kiichi

    2017-01-01

    In this paper, we present the design and experimental verification of an amperometric CMOS-based sensor with a current integrator and a 1.2 × 2.05 µm2 bacterial-sized microelectrode array for high-sensitivity bacterial counting. For high-sensitivity bacterial counting with a sufficient signal-to-noise ratio (SNR), noise must be reduced because bacterial-sized microelectrodes can handle only a low current of the order of 100 pA. Thus, we implement a current integrator that is highly effective for noise reduction. Furthermore, for the first time, we use the current integrator in conjunction with the bacterial-sized microelectrode array. On the basis of the results of the proposed current integration, we successfully reduce noise and achieve a high SNR of 30.4 dB. To verify the effectiveness of the proposed CMOS-based sensor, we perform two-dimensional counting of microbeads, which are almost of the same size as bacteria. The measurement results demonstrate successful high-sensitivity two-dimensional (2D) counting of microbeads with a high SNR of 27 dB.

  4. Livetime and sensitivity of the ARIANNA Hexagonal Radio Array

    CERN Document Server

    Barwick, S W; Besson, D Z; Binder, G; Binns, W R; Boersma, D; Bose, R G; Braun, D L; Buckley, J H; Bugaev, V; Buitink, S; Dookayka, K; Dowkontt, P F; Duffin, T; Euler, S; Gerhardt, L; Gustafsson, L; Hallgren, A; Hanson, J C; Israel, M H; Kiryluk, J; Klein, S; Kleinfelder, S; Nelles, A; Niederhausen, H; Olevitch, M A; Persichelli, C; Ratzlaff, K; Rauch, B F; Reed, C; Roumi, M; Samanta, A; Simburger, G E; Stezelberger, T; Tatar, J; Uggerhoj, U; Walker, J; Young, R

    2015-01-01

    The ARIANNA collaboration completed the installation of the hexagonal radio array (HRA) in December 2014, serving as a pilot program for a planned high energy neutrino telescope located about 110 km south of McMurdo Station on the Ross Ice Shelf near the coast of Antarctica. The goal of ARIANNA is to measure both diffuse and point fluxes of astrophysical neutrinos at energies in excess of 1016 eV. Upgraded hardware has been installed during the 2014 deployment season and stations show a livetime of better than 90% between commissioning and austral sunset. Though designed to observe radio pulses from neutrino interactions originating within the ice below each detector, one station was modified to study the low-frequency environment and signals from above. We provide evidence that the HRA observed both continuous emission from the Galaxy and a transient solar burst. Preliminary work on modeling the (weak) Galactic signal confirm the absolute sensitivity of the HRA detector system.

  5. High-Sensitivity Spectrophotometry.

    Science.gov (United States)

    Harris, T. D.

    1982-01-01

    Selected high-sensitivity spectrophotometric methods are examined, and comparisons are made of their relative strengths and weaknesses and the circumstances for which each can best be applied. Methods include long path cells, noise reduction, laser intracavity absorption, thermocouple calorimetry, photoacoustic methods, and thermo-optical methods.…

  6. High-performance and low-cost dye-sensitized solar cells based on kesterite Cu2ZnSnS4 nanoplate arrays on a flexible carbon cloth cathode

    Science.gov (United States)

    Chen, Shan-Long; Tao, Jie; Tao, Hai-Jun; Shen, Yi-Zhou; Wang, Tao; Pan, Lei

    2016-10-01

    Kesterite Cu2ZnSnS4 (CZTS) wide application is hindered by poor electrical conductivity, although it is a promising counter electrode (CE) material for dye-sensitized solar cells (DSSCs), due to its excellent catalytic activity, hierarchical microstructure, and natural abundance. Inspired by the advantages of flexible carbon cloth, with high conductivity and expanded surface area, we designed and fabricated single-crystal CZTS nanoplate arrays (NPLAr) on flexible carbon cloth as DSSCs cathode directly, demonstrating a power conversion efficiency of 7.53% and a long-operation life performance. The outstanding performance was ascribed from the high catalytic activity, good conductive framework, effective photo-generated electron migration, and high iodide species diffusion rate of the composite CE. Our present results demonstrate that the novel and flexible CZTS/Carbon Cloth composite structure is an alternative and high-efficiency Pt-free counter electrode in dye-sensitized solar cells.

  7. Dispersive liquid-liquid microextraction followed by high-performance liquid chromatography-diode array detection as an efficient and sensitive technique for determination of antioxidants.

    Science.gov (United States)

    Farajzadeh, Mir Ali; Bahram, Morteza; Jönsson, Jan Ake

    2007-05-15

    Dispersive liquid-liquid microextraction (DLLME) and high performance liquid chromatography-diode array detection (HPLC-DAD) was presented for extraction and determination of Irganox 1010, Irganox 1076 and Irgafos 168 (antioxidants) in aqueous samples. Carbon tetrachloride at microliter volume level and acetonitrile were used as extraction and dispersive solvents, respectively. The main advantages of method are high speed, high enrichment factor, high recovery, good repeatability and extraction solvent volume at microL level. Limit of detection for analytes is between 3 and 7 ng mL(-1). One variable at a time optimization and response surface modeling were used to obtain optimum conditions for microextraction procedure and nearly same experimental conditions were obtained using both optimization methods. Recoveries in the ranges 78-86% and 84-110% were obtained by one variable at a time and response surface modeling, respectively. Using tap water and packed water as matrices do not show any detrimental effect on the extraction recoveries and enrichment factors of analytes.

  8. Highly Sensitive Optical Receivers

    CERN Document Server

    Schneider, Kerstin

    2006-01-01

    Highly Sensitive Optical Receivers primarily treats the circuit design of optical receivers with external photodiodes. Continuous-mode and burst-mode receivers are compared. The monograph first summarizes the basics of III/V photodetectors, transistor and noise models, bit-error rate, sensitivity and analog circuit design, thus enabling readers to understand the circuits described in the main part of the book. In order to cover the topic comprehensively, detailed descriptions of receivers for optical data communication in general and, in particular, optical burst-mode receivers in deep-sub-µm CMOS are presented. Numerous detailed and elaborate illustrations facilitate better understanding.

  9. Instrument contributions to resolution and sensitivity in ultra high performance liquid chromatography using small bore columns: comparison of diode array and triple quadrupole mass spectrometry detection.

    Science.gov (United States)

    Buckenmaier, Stephan; Miller, Christine A; van de Goor, Tom; Dittmann, Monika M

    2015-01-16

    UHPLC with DAD-UV detection or in combination with mass spectrometry (MS) has proven to be a robust and widely applicable platform for high sensitivity analyses of many types of chemical compounds. The majority of users employ narrow bore columns with 2.1mm internal diameter (ID) typically exhibiting very high efficiencies (>200,000 plates/m). This ultimately sets stringent demands upon the chromatographic system as the separation efficiency can be compromised by external contributions to dispersion caused by connection capillaries, auto-sampler and/or the detection device. Sample limited applications often use reduced column diameters down to capillary- or even nano-column format. Capillary (ID≤0.5mm) or small-bore columns (ID≤1mm) can be a good compromise between system robustness and enhanced sensitivity. Yet in this case, extra-column dispersion gains additional importance due to reduced peak volumes. To design an optimized system configuration for specific column dimensions and applications it is crucial to understand the dispersion contributions of individual extra-column components. This was subject to many studies done within our group and by others. Here, we employed a fully optimized UHPLC/UV system to investigate the contribution to peak dispersion obtained from columns ranging from capillary to narrow bore (0.3, 0.5, 1, 2.1mm) using a set of small molecules that were analyzed in gradient mode. Further UV detection was replaced by a triple quadrupole (QQQ) MS in order to evaluate its contribution to band broadening. In this context the impact of column-ID upon MS sensitivity when interfaced with an Agilent Jet Stream source was investigated. Data obtained from our test suite of compounds shows mostly mass-sensitive behavior of this advanced electrospray technology.

  10. Human transcriptome array for high-throughput clinical studies.

    Science.gov (United States)

    Xu, Weihong; Seok, Junhee; Mindrinos, Michael N; Schweitzer, Anthony C; Jiang, Hui; Wilhelmy, Julie; Clark, Tyson A; Kapur, Karen; Xing, Yi; Faham, Malek; Storey, John D; Moldawer, Lyle L; Maier, Ronald V; Tompkins, Ronald G; Wong, Wing Hung; Davis, Ronald W; Xiao, Wenzhong

    2011-03-01

    A 6.9 million-feature oligonucleotide array of the human transcriptome [Glue Grant human transcriptome (GG-H array)] has been developed for high-throughput and cost-effective analyses in clinical studies. This array allows comprehensive examination of gene expression and genome-wide identification of alternative splicing as well as detection of coding SNPs and noncoding transcripts. The performance of the array was examined and compared with mRNA sequencing (RNA-Seq) results over multiple independent replicates of liver and muscle samples. Compared with RNA-Seq of 46 million uniquely mappable reads per replicate, the GG-H array is highly reproducible in estimating gene and exon abundance. Although both platforms detect similar expression changes at the gene level, the GG-H array is more sensitive at the exon level. Deeper sequencing is required to adequately cover low-abundance transcripts. The array has been implemented in a multicenter clinical program and has generated high-quality, reproducible data. Considering the clinical trial requirements of cost, sample availability, and throughput, the GG-H array has a wide range of applications. An emerging approach for large-scale clinical genomic studies is to first use RNA-Seq to the sufficient depth for the discovery of transcriptome elements relevant to the disease process followed by high-throughput and reliable screening of these elements on thousands of patient samples using custom-designed arrays.

  11. Miniaturization of a micro-optics array for highly sensitive and parallel detection on an injection moulded lab-on-a-chip

    DEFF Research Database (Denmark)

    Hung, Tran Quang; Sun, Yi; Poulsen, Carl Esben

    2015-01-01

    A miniaturised array of supercritical angle fluorescence (SAF) micro-optics embedded in a microfluidic chamber was fabricated by injection moulding. The fabricated chip could enhance the fluorescence signal around 46 times compared to a conventional microscope. Collection of the fluorescence signal...

  12. High density arrays of micromirrors

    Energy Technology Data Exchange (ETDEWEB)

    Folta, J. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Decker, J. Y. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kolman, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lee, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Brase, J. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    1999-02-01

    We established and achieved our goal to (1) fabricate and evaluate test structures based on the micromirror design optimized for maskless lithography applications, (2) perform system analysis and code development for the maskless lithography concept, and (3) identify specifications for micromirror arrays (MMAs) for LLNL's adaptive optics (AO) applications and conceptualize new devices.

  13. Piezoresistive Probe Array for High Throughput Applications

    NARCIS (Netherlands)

    Gaitas, A.; French, P.

    2011-01-01

    Microcantilevers are used in a number of applications including atomic-force microscopy (AFM). In this work, piezoresistive deflection-sensing elements are integrated onto micromachined cantilevers to increase sensitivity, and reduce complexity and cost. An array of probes with 5 nm gold ultrathin f

  14. In vivo sensitivity estimation and imaging acceleration with rotating RF coil arrays at 7 Tesla.

    Science.gov (United States)

    Li, Mingyan; Jin, Jin; Zuo, Zhentao; Liu, Feng; Trakic, Adnan; Weber, Ewald; Zhuo, Yan; Xue, Rong; Crozier, Stuart

    2015-03-01

    Using a new rotating SENSitivity Encoding (rotating-SENSE) algorithm, we have successfully demonstrated that the rotating radiofrequency coil array (RRFCA) was capable of achieving a significant reduction in scan time and a uniform image reconstruction for a homogeneous phantom at 7 Tesla. However, at 7 Tesla the in vivo sensitivity profiles (B1(-)) become distinct at various angular positions. Therefore, sensitivity maps at other angular positions cannot be obtained by numerically rotating the acquired ones. In this work, a novel sensitivity estimation method for the RRFCA was developed and validated with human brain imaging. This method employed a library database and registration techniques to estimate coil sensitivity at an arbitrary angular position. The estimated sensitivity maps were then compared to the acquired sensitivity maps. The results indicate that the proposed method is capable of accurately estimating both magnitude and phase of sensitivity at an arbitrary angular position, which enables us to employ the rotating-SENSE algorithm to accelerate acquisition and reconstruct image. Compared to a stationary coil array with the same number of coil elements, the RRFCA was able to reconstruct images with better quality at a high reduction factor. It is hoped that the proposed rotation-dependent sensitivity estimation algorithm and the acceleration ability of the RRFCA will be particularly useful for ultra high field MRI. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Sensitivity and Noise of Cold-Electron Bolometer Arrays

    Science.gov (United States)

    Mukhin, A. S.; Gordeeva, A. V.; Revin, L. S.; Abashin, A. E.; Shishov, A. A.; Pankratov, A. L.; Mahashabde, S.; Kuzmin, L. S.

    2017-01-01

    We perform experimental and theoretical studies of the series-parallel arrays of the cold-electron bolometers integrated into a cross-slot antenna and composed with an immersion silicon lens. This work is aimed at determining the efficiency of radiation absorption by bolometers, their volt-watt sensitivity, and equivalent noise power. The absorbed power was found using two independent methods, which ensured a better reliability of the results. The first method is based on comparing the experimental current-voltage characteristics of bolometers with the model based on the heat-balance equation. The second approach involves simulation of the electromagnetic properties of the system including the antenna, the lens, the bandpass filters, and the radiation source. The discrepancy among the results obtained using various methods does not exceed 30%. Optimization of the experimental setup is proposed to reach the photon-noise detection regime.

  16. High speed adaptive liquid microlens array

    NARCIS (Netherlands)

    Murade, C.U.; van den Ende, Henricus T.M.; Mugele, Friedrich Gunther

    2012-01-01

    Liquid microlenses are attractive for adaptive optics because they offer the potential for both high speed actuation and parallelization into large arrays. Yet, in conventional designs, resonances of the liquid and the complexity of driving mechanisms and/or the device architecture have hampered a

  17. Extraction and Quantification of Tryptophan and Kynurenine from Cultured Cells and Media Using a High Performance Liquid Chromatography (HPLC) System Equipped with an Ultra-Sensitive Diode Array Detector

    Science.gov (United States)

    Kim, Jeffrey; Stewart, Benjamin; Weiss, Robert H

    2016-01-01

    Evidence of the involvement of tryptophan and its metabolite, kynurenine, in various biological processes including cancer is constantly expanding. Analysis of cell extracts and culture media can allow for quick snapshots of the metabolic fluctuations occurring in vitro. Here, we describe a method for metabolite extraction from mammalian cells and analysis of extracted metabolites and cell culture media by HPLC with detection using an ultra-sensitive diode array detector. PMID:27213172

  18. High-Sensitivity Magnetization Measurements

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The three most common instruments for high-sensitivity magnetization measurements (the vibrating-sample magnetometer, the alternating gradient magnetometer, and the SQUID magne tometer) are described and their limiting sensitivities are discussed. The advantages and disad vantages of each are described. Magnetometers using micro-machined force detectors are briefly mentioned.

  19. Submicrometer-scale ZnO Composite Aggregate Arrays Photoanodes for Dye-sensitized Solar Cells

    Institute of Scientific and Technical Information of China (English)

    Wei Jia; Suihu Dang; Hairui Liu; Zhuxia Zhang; Tianbao Li; Xuguang Liu; Bingshe Xu

    2013-01-01

    Submicrometer-scale ZnO composite aggregate arrays of nanorods and nanoparticles were prepared by simple wet-chemical route and studied as dye-sensitized solar cells (DSSCs) photoanodes.The ZnO composite aggregate arrays significantly improved the efficiency of DSSCs due to their relatively high surface area,fast electron transport,and enhanced light-scattering capability.A short current density (Jsc) of 11.7 mA/cm2 and an overall solar-to-electric energy conversion efficiency (η) of 3.17% were achieved for the ZnO composite aggregate DSSCs,which were much higher than those obtained for the monodisperse aggregate DSSCs (Jsc=6.9mA/cm2,η=1.51 %) and ZnO nanorod array DSSCs (Jsc =4.2 mA/cm2,η=0.61%).

  20. Sensitive characterization of polyphenolic antioxidants in Polygonatum odoratum by selective solid phase extraction and high performance liquid chromatography-diode array detector-quadrupole time-of-flight tandem mass spectrometry.

    Science.gov (United States)

    Hu, Xin; Zhao, Huading; Shi, Shuyun; Li, Hui; Zhou, Xiaoling; Jiao, Feipeng; Jiang, Xinyu; Peng, Dongming; Chen, Xiaoqin

    2015-08-10

    The complexity of natural products always leads to the co-elution of interfering compounds with bioactive compounds, which then has a detrimental effect on structural elucidation. Here, a new method, based on selective solid phase extraction combined with 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) spiking and high performance liquid chromatography-diode array detector-quadrupole time-of-flight tandem mass spectrometry (HPLC-DAD-QTOF-MS/MS), is described for sensitive screening, selective extraction and identification of polyphenolic antioxidants in Polygonatum odoratum. First, 25 polyphenolic antioxidants (1-25) were screened by DPPH spiking with HPLC. Second, polydopamine coated Fe3O4 microspheres (Fe3O4@PDA) were prepared to selectively extract target antioxidants with extraction efficiency from 55% to 100% when the amount of Fe3O4@PDA, extraction time, desorption solvent and time were 10mg, 20 min, acetonitrile, and 5 min. Third, 25 antioxidants (10 cinnamides and 15 homoisoflavanones) were identified by HPLC-DAD-QTOF-MS/MS. Furthermore, the DPPH scavenging activities of purified compounds (IC50, 1.6-32.8 μg/mL) validated the method. Among the identified antioxidants, four of them (12, 13, 18 and 19) were new compounds, four of them (2, 4, 8 and 14) were first obtained from family Liliaceae, five of them (1, 3, 5, 7 and 9) were first reported in genus Polygonatum, while one compound (24) was first identified in this species. The results indicated that the proposed method was an efficient and sensitive approach to explore polyphenolic antioxidants from complex natural products. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. High-Temperature Gas Sensor Array (Electronic Nose) Demonstrated

    Science.gov (United States)

    Hunter, Gary W.

    2002-01-01

    The ability to measure emissions from aeronautic engines and in commercial applications such as automotive emission control and chemical process monitoring is a necessary first step if one is going to actively control those emissions. One single sensor will not give all the information necessary to determine the chemical composition of a high-temperature, harsh environment. Rather, an array of gas sensor arrays--in effect, a high-temperature electronic "nose"--is necessary to characterize the chemical constituents of a diverse, high-temperature environment, such as an emissions stream. The signals produced by this nose could be analyzed to determine the constituents of the emission stream. Although commercial electronic noses for near-room temperature applications exist, they often depend significantly on lower temperature materials or only one sensor type. A separate development effort necessary for a high-temperature electronic nose is being undertaken by the NASA Glenn Research Center, Case Western Reserve University, Ohio State University, and Makel Engineering, Inc. The sensors are specially designed for hightemperature environments. A first-generation high-temperature electronic nose has been demonstrated on a modified automotive engine. This nose sensor array was composed of sensors designed for hightemperature environments fabricated using microelectromechanical-systems- (MEMS-) based technology. The array included a tin-oxide-based sensor doped for nitrogen oxide (NOx) sensitivity, a SiC-based hydrocarbon (CxHy) sensor, and an oxygen sensor (O2). These sensors operate on different principles--resistor, diode, and electrochemical cell, respectively--and each sensor has very different responses to the individual gases in the environment. A picture showing the sensor head for the array is shown in the photograph on the left and the sensors installed in the engine are shown in the photograph on the right. Electronics are interfaced with the sensors for

  2. Sensitivity Analysis of WEC Array Layout Parameters Effect on the Power Performance

    DEFF Research Database (Denmark)

    Ruiz, Pau Mercadé; Ferri, Francesco; Kofoed, Jens Peter

    2015-01-01

    This study assesses the effect that the array layout choice has on the power performance. To this end, a sensitivity analysis is carried out with six array layout parameters, as the simulation inputs, the array power performance (q-factor), as the simulation output, and a simulation model specially...... developed in cooperation with the DTOcean research project, which aims to provide design tools for the deployment of the first generation of ocean energy converter arrays. The sensitivity analysis is performed for the particular case of an array of floating cylinders moving in the usual six rigid body...

  3. Column Grid Array Rework for High Reliability

    Science.gov (United States)

    Mehta, Atul C.; Bodie, Charles C.

    2008-01-01

    Due to requirements for reduced size and weight, use of grid array packages in space applications has become common place. To meet the requirement of high reliability and high number of I/Os, ceramic column grid array packages (CCGA) were selected for major electronic components used in next MARS Rover mission (specifically high density Field Programmable Gate Arrays). ABSTRACT The probability of removal and replacement of these devices on the actual flight printed wiring board assemblies is deemed to be very high because of last minute discoveries in final test which will dictate changes in the firmware. The questions and challenges presented to the manufacturing organizations engaged in the production of high reliability electronic assemblies are, Is the reliability of the PWBA adversely affected by rework (removal and replacement) of the CGA package? and How many times can we rework the same board without destroying a pad or degrading the lifetime of the assembly? To answer these questions, the most complex printed wiring board assembly used by the project was chosen to be used as the test vehicle, the PWB was modified to provide a daisy chain pattern, and a number of bare PWB s were acquired to this modified design. Non-functional 624 pin CGA packages with internal daisy chained matching the pattern on the PWB were procured. The combination of the modified PWB and the daisy chained packages enables continuity measurements of every soldered contact during subsequent testing and thermal cycling. Several test vehicles boards were assembled, reworked and then thermal cycled to assess the reliability of the solder joints and board material including pads and traces near the CGA. The details of rework process and results of thermal cycling are presented in this paper.

  4. GMR biosensor arrays: correction techniques for reproducibility and enhanced sensitivity.

    Science.gov (United States)

    Hall, D A; Gaster, R S; Osterfeld, S J; Murmann, B; Wang, S X

    2010-05-15

    Giant magnetoresistive biosensors possess great potential in biomedical applications for quantitatively detecting magnetically tagged biomolecules. Magnetic sensing does not suffer from the high background levels found in optical sensing modalities such as the enzyme linked immunosorbent assay translating into a technology with higher sensitivity. However, to reveal the full potential of these sensors and compensate for non-idealities such as temperature dependence, digital correction and calibration techniques are not only useful but imperative. Using these calibration techniques to correct for process variations and dynamic changes in the sensing environment (such as temperature and magnetic field), we are able to obtain extremely sensitive and, more importantly, reproducible results for quantifiable biomolecular reorganization. The reproducibility of the system was improved by over 3 x using digital correction techniques and the sensors are made temperature independent by using a novel background correction technique. 2010 Elsevier B.V. All rights reserved.

  5. Highly tunable plasmonic nanoring arrays for nanoparticle manipulation and detection

    Science.gov (United States)

    Sergides, M.; Truong, V. G.; Chormaic, S. Nic

    2016-09-01

    The advancement of trapping and detection of nano-objects at very low laser powers in the near-infra-red region (NIR) is crucial for many applications. Singular visible-light nano-optics based on abrupt phase changes have recently demonstrated a significant improvement in molecule detection. Here, we propose and demonstrate tunable plasmonic nanodevices, which can improve both the trapping field enhancement and detection of nano-objects using singular phase drops in the NIR range. The plasmonic nanostructures, which consist of gaps with dimensions 50 nm × 50 nm connecting nanorings in arrays is discussed. These gaps act as individual detection and trapping sites. The tunability of the system is evident from extinction and reflection spectra while increasing the aperture size in the arrays. Additionally, in the region where the plasmonic nano-array exhibits topologically-protected, near-zero reflection behaviour, the phase displays a rapid change. Our experimental data predict that, using this abrupt phase changes, one can improve the detection sensitivity by 10 times compared to the extinction spectra method. We finally report experimental evidence of 100 nm polystyrene beads trapping using low incident power on these devices. The overall design demonstrates strong capability as an optical, label-free, non-destructive tool for single molecule manipulation where low trapping intensity, minimal photo bleaching and high sensitivity is required.

  6. Recent progress in all-solid-state quantum dot-sensitized TiO{sub 2} nanotube array solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qingyao, E-mail: wangqingyao0532@163.com [Ludong University, School of Chemistry and Materials Science (China); Chen, Chao; Liu, Wei [Tongji University, School of Materials Science and Engineering (China); Gao, Shanmin [Ludong University, School of Chemistry and Materials Science (China); Yang, Xiuchun, E-mail: yangxc@tongji.edu.cn [Tongji University, School of Materials Science and Engineering (China)

    2016-01-15

    All-solid-state quantum dot-sensitized TiO{sub 2} nanotube array solar cells have been drawing great attention to solar energy conversion, which break through restrictions in traditional solar cells, such as the high recombination at interfaces of porous TiO{sub 2} films/sensitizers/hole conductors/counter electrodes, instability of dyes, and leakage of solution electrolyte, and so the novel solar cells exhibit promising applications in the future. In this Minireview article, the assembling of solar cells including the preparation of TiO{sub 2} nanotube array photoanodes, quantum dot preparation and sensitization on photoanodes, filling of hole conductors in TiO{sub 2} nanotubes, and selection of counter electrodes are overviewed, and the development course of all-solid-state quantum dot-sensitized TiO{sub 2} nanotube array solar cells in recent years are summarized in detail. Moreover, the influences of TiO{sub 2} nanotube array photoanodes, quantum dots, solid electrolyte, and counter electrodes on photon-to-current efficiencies of solar cells are summarized. In addition, current problems of solid-state quantum dot-sensitized TiO{sub 2} nanotube array solar cells are analyzed, and the corresponding improvements, such as multisensitizers and passivation layers, are proposed to improve the photoelectric conversion efficiency. Finally, this Minireview provides a perspective for the future development of this novel solar cell.

  7. Development of high frequency annular array ultrasound transducers

    Science.gov (United States)

    Gottlieb, Emanuel John

    The advantage of ultrasonic annular arrays over conventional single element transducers has been in the ability to transmit focus at multiple points throughout the depth of field, as well as receive dynamic focus. Today, annular, linear and multidimensional array imaging systems are not commercially available at frequencies greater than 20 MHz. The fabrication technology used to develop a high frequency (>50 MHz) annular array transducer is presented. A 9 mum P(VDF-TrFE) film was bonded to gold annuli electrodes on the top layer of a two sided polyimide flexible circuit. Each annulus was separated by a 30 mum kerf and had several electroplated micro vias that connected to electrode traces on the bottom side of the polyimide flexible circuit. The array's performance was evaluated by measuring the electrical impedance, pulse echo response and crosstalk measurement for each element in the array. In order to improve device sensitivity each element was electrically matched to an impedance magnitude of 50 O and 0° phase at resonance. The average round trip insertion loss measured for the array and compensated for diffraction effects was -33.5 dB. The measured average center frequency and bandwidth of an element was 55 MHz and 47 respectively. The measured crosstalk between adjacent elements remained below -29 dB at the center frequency in water. A vertical wire phantom was imaged using a single focus transmit beamformer and dynamic focusing receive beamformer. This image showed a significant improvement in lateral resolution over a range of 9 mm after the dynamic focusing receive algorithm was applied. These results correlated well with predictions from a Field II simulation. After beamforming the minimum lateral resolution (-6 dB) was 108 mum at the focus. Preliminary ultrasound B-mode images of the rabbit eye using this transducer were shown in conjunction with a multi-channel digital beamformer. A feasibility study of designing and fabricating tunable copolymer

  8. Detection of volatile compounds with mass-sensitive sensor arrays in the presence of variable ambient humidity.

    Science.gov (United States)

    Dickert, F L; Hayden, O; Zenkel, M E

    1999-04-01

    Mass-sensitive sensor arrays were established for the detection of isomeric or highly analogue analyte mixtures, which show similar physical and morphological properties. Supramolecular host-guest chemistry and arrays of four mass-sensitive quartz crystal microbalances have been successfully combined with multivariate calibration techniques in the presence of variable air moisture. This system enabled even the separation of xylene isomers [Formula: see text] a task that might be crucial even by gas chromatography. The data of the sensor arrays were analyzed with partial least squares and artificial neural networks. The xylene isomers could be detected with an accuracy of ∼1% in the range of 0-200 ppm, nearly eliminating the residual water cross-sensitivity of the sensor coatings, which allows effective work place or environmental monitoring of toxic compounds with fast response levels.

  9. THE BARYON ACOUSTIC OSCILLATION BROADBAND AND BROAD-BEAM ARRAY: DESIGN OVERVIEW AND SENSITIVITY FORECASTS

    Energy Technology Data Exchange (ETDEWEB)

    Pober, Jonathan C.; Parsons, Aaron R.; McQuinn, Matthew; Ali, Zaki [Astronomy Department, University of California, Berkeley, CA (United States); DeBoer, David R. [Radio Astronomy Laboratory, University of California, Berkeley, CA (United States); McDonald, Patrick [Physics Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Aguirre, James E. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA (United States); Bradley, Richard F. [Astronomy Department and Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA (United States); Chang, Tzu-Ching [Institute of Astronomy and Astrophysics, Academia Sinica, Taipei, Taiwan (China); Morales, Miguel F. [Department of Physics, University of Washington, Seattle, WA (United States)

    2013-03-15

    This work describes a new instrument optimized for a detection of the neutral hydrogen 21 cm power spectrum between redshifts of 0.5 and 1.5: the Baryon Acoustic Oscillation Broadband and Broad-beam (BAOBAB) array. BAOBAB will build on the efforts of a first generation of 21 cm experiments that are targeting a detection of the signal from the Epoch of Reionization at z {approx} 10. At z {approx} 1, the emission from neutral hydrogen in self-shielded overdense halos also presents an accessible signal, since the dominant, synchrotron foreground emission is considerably fainter than at redshift 10. The principle science driver for these observations are baryon acoustic oscillations in the matter power spectrum which have the potential to act as a standard ruler and constrain the nature of dark energy. BAOBAB will fully correlate dual-polarization antenna tiles over the 600-900 MHz band with a frequency resolution of 300 kHz and a system temperature of 50 K. The number of antennas will grow in staged deployments, and reconfigurations of the array will allow for both traditional imaging and high power spectrum sensitivity operations. We present calculations of the power spectrum sensitivity for various array sizes, with a 35 element array measuring the cosmic neutral hydrogen fraction as a function of redshift, and a 132 element system detecting the BAO features in the power spectrum, yielding a 1.8% error on the z {approx} 1 distance scale, and, in turn, significant improvements to constraints on the dark energy equation of state over an unprecedented range of redshifts from {approx}0.5 to 1.5.

  10. Acoustic trapping with a high frequency linear phased array

    OpenAIRE

    Zheng, Fan; Ying LI; Hsu, Hsiu-Sheng; Liu, Changgeng; Tat Chiu, Chi; Lee, Changyang; Ham Kim, Hyung; Shung, K. Kirk

    2012-01-01

    A high frequency ultrasonic phased array is shown to be capable of trapping and translating microparticles precisely and efficiently, made possible due to the fact that the acoustic beam produced by a phased array can be both focused and steered. Acoustic manipulation of microparticles by a phased array is advantageous over a single element transducer since there is no mechanical movement required for the array. Experimental results show that 45 μm diameter polystyrene microspheres can be eas...

  11. Sensitivity enhancement of grating interferometer based two-dimensional sensor arrays using two-wavelength readout

    Energy Technology Data Exchange (ETDEWEB)

    Ferhanoglu, Onur; Urey, Hakan

    2011-07-01

    Diffraction gratings integrated with microelectromechanical systems (MEMS) sensors offer displacement measurements with subnanometer sensitivity. However, the sensitivity of the interferometric readout may drop significantly based on the gap between the grating and the reference surface. A two-wavelength (2-{lambda}) readout method was previously tested using a single MEMS sensor for illustrating increased displacement measurement capability. This work demonstrates sensitivity enhancement on a sensor array with large scale parallelization ({approx}20,000 sensors). The statistical representation, which is developed to model sensitivity enhancement within a grating based sensor array, is supported by experimental results using a thermal sensor array. In the experiments, two lasers at different wavelengths (633 and 650 nm) illuminate the thermal sensor array from the backside, time-sequentially. The diffracted first order light from the array is imaged onto a single CCD camera. The target scene is reconstructed by observing the change in the first diffracted order diffraction intensity for both wavelengths. Merging of the data from two measurements with two lasers was performed by taking the larger of the two CCD measurements with respect to the reference image for each sensor. {approx}30% increase in the average sensitivity was demonstrated for a 160x120 pixel IR sensor array. Proposed architecture is also applicable to a variety of sensing applications, such as parallel biosensing and atomic force microscopy, for improved displacement measurements and enhanced sensitivity.

  12. Sensitivity enhancement of grating interferometer based two-dimensional sensor arrays using two-wavelength readout.

    Science.gov (United States)

    Ferhanoglu, Onur; Urey, Hakan

    2011-07-01

    Diffraction gratings integrated with microelectromechanical systems (MEMS) sensors offer displacement measurements with subnanometer sensitivity. However, the sensitivity of the interferometric readout may drop significantly based on the gap between the grating and the reference surface. A two-wavelength (2-λ) readout method was previously tested using a single MEMS sensor for illustrating increased displacement measurement capability. This work demonstrates sensitivity enhancement on a sensor array with large scale parallelization (~20,000 sensors). The statistical representation, which is developed to model sensitivity enhancement within a grating based sensor array, is supported by experimental results using a thermal sensor array. In the experiments, two lasers at different wavelengths (633 and 650 nm) illuminate the thermal sensor array from the backside, time-sequentially. The diffracted first order light from the array is imaged onto a single CCD camera. The target scene is reconstructed by observing the change in the first diffracted order diffraction intensity for both wavelengths. Merging of the data from two measurements with two lasers was performed by taking the larger of the two CCD measurements with respect to the reference image for each sensor. ~30% increase in the average sensitivity was demonstrated for a 160×120 pixel IR sensor array. Proposed architecture is also applicable to a variety of sensing applications, such as parallel biosensing and atomic force microscopy, for improved displacement measurements and enhanced sensitivity.

  13. 2D SQIF arrays using 20 000 YBCO high R n Josephson junctions

    Science.gov (United States)

    Mitchell, E. E.; Hannam, K. E.; Lazar, J.; Leslie, K. E.; Lewis, C. J.; Grancea, A.; Keenan, S. T.; Lam, S. K. H.; Foley, C. P.

    2016-06-01

    Superconducting quantum interference filters (SQIFs) have been created using two dimensional arrays of YBCO step-edge Josephson junctions connected together in series and parallel configurations via superconducting loops with a range of loop areas and loop inductances. A SQIF response, as evidenced by a single large anti-peak at zero applied flux, is reported at 77 K for step-edge junction arrays with the junction number N = 1 000 up to 20 000. The SQIF sensitivity (slope of peak) increased linearly with N up to a maximum of 1530 V T-1. Array parameters related to geometry and average junction characteristics are investigated in order to understand and improve the SQIF performance in high temperature superconducting arrays. Initial investigations also focus on the effect of the SQUID inductance factor on the SQIF sensitivity by varying both the mean critical current and the mean inductance of the loops in the array. The RF response to a 30 MHz signal is demonstrated.

  14. Exploration of highly accelerated magnetic resonance elastography using high-density array coils

    Science.gov (United States)

    Bosshard, John C.; Yallapragada, Naresh; McDougall, Mary P.

    2017-01-01

    Background Magnetic resonance elastography (MRE) measures tissue mechanical properties by applying a shear wave and capturing its propagation using magnetic resonance imaging (MRI). By using high density array coils, MRE images are acquired using single echo acquisition (SEA) and at high resolutions with significantly reduced scan times. Methods Sixty-four channel uniplanar and 32×32 channel biplanar receive arrays are used to acquire MRE wave image sets from agar samples containing regions of varying stiffness. A mechanical actuator triggered by a stepped delay time introduces vibrations into the sample while a motion sensitizing gradient encodes micrometer displacements into the phase. SEA imaging is used to acquire each temporal offset in a single echo, while multiple echoes from the same array are employed for highly accelerated imaging at high resolutions. Additionally, stiffness variations as a function of temperature are studied by using a localized heat source above the sample. A custom insertable gradient coil is employed for phase compensation of SEA imaging with the biplanar array to allow imaging of multiple slices. Results SEA MRE images show a mechanical shear wave propagating into and across agar samples. A set of 720 images was obtained in 720 echoes, plus a single reference scan for both harmonic and transient MRE. A set of 2,950 wave image frames was acquired from pairs of SEA images captured during heating, showing the change in mechanical wavelength with the change in agar properties. A set of 240 frames was acquired from two slices simultaneously using the biplanar array, with phase images processed into displacement maps. Combining the narrow sensitivity patterns and SNR advantage of the SEA array coil geometry allowed acquisition of a data set with a resolution of 156 µm × 125 µm × 1,000 µm in only 64 echoes, demonstrating high resolution and high acceleration factors. Conclusions MRE using high-density arrays offers the unique ability

  15. The effects of anodization parameters on titania nanotube arrays and dye sensitized solar cells

    Science.gov (United States)

    Xie, Z. B.; Adams, S.; Blackwood, D. J.; Wang, J.

    2008-10-01

    Ordered, closely packed, and vertically oriented titania nanotube arrays with lengths exceeding 10 µm were fabricated by anodization of titanium foils. The effects of anodization voltage and time on the microstructural morphology and the photovoltaic performance of dye sensitized solar cells based on the titania nanotube arrays were investigated. On increasing the anodization voltage or time, the increase in active surface area leads to enhanced photovoltaic currents and thereby an overall higher performance of the dye sensitized solar cells. The efficiency enhancement with rising anodization voltage exceeds the increase in the outer surface area of the nanotubes, indicating that the active surface area is further enlarged by a more accessible inner surface of the nanotube arrays grown with a higher anodization voltage. A promising efficiency of 3.67% for dye sensitized solar cells based on anodized titania nanotube arrays was achieved under AM1.5, 100 mW cm-2 illumination.

  16. The effects of anodization parameters on titania nanotube arrays and dye sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Z B; Adams, S; Blackwood, D J; Wang, J [Department of Materials Science and Engineering, National University of Singapore, Singapore 117574 (Singapore)], E-mail: msexz@nus.edu.sg

    2008-10-08

    Ordered, closely packed, and vertically oriented titania nanotube arrays with lengths exceeding 10 {mu}m were fabricated by anodization of titanium foils. The effects of anodization voltage and time on the microstructural morphology and the photovoltaic performance of dye sensitized solar cells based on the titania nanotube arrays were investigated. On increasing the anodization voltage or time, the increase in active surface area leads to enhanced photovoltaic currents and thereby an overall higher performance of the dye sensitized solar cells. The efficiency enhancement with rising anodization voltage exceeds the increase in the outer surface area of the nanotubes, indicating that the active surface area is further enlarged by a more accessible inner surface of the nanotube arrays grown with a higher anodization voltage. A promising efficiency of 3.67% for dye sensitized solar cells based on anodized titania nanotube arrays was achieved under AM1.5, 100 mW cm{sup -2} illumination.

  17. Sensitive chiral high-performance liquid chromatographic determination of anthelmintic flubendazole and its phase I metabolites in blood plasma using UV photodiode-array and fluorescence detection Application to pharmacokinetic studies in sheep.

    Science.gov (United States)

    Nobilis, Milan; Vybíralová, Zuzana; Krízová, Veronika; Kubícek, Vladimír; Soukupová, Marie; Lamka, Jirí; Szotáková, Barbora; Skálová, Lenka

    2008-12-01

    Although benzimidazole anthelmintic flubendazole, methyl ester of [5-(4-fluorobenzoyl)-1H-benzimidazol-2-yl]carbamic acid, is extensively used in veterinary and human medicine for the treatment of gastrointestinal parasitic helminth infections, reliable data about its pharmacokinetics in various species have not been reported. Our previous work [M. Nobilis, Th. Jira, M. Lísa, M. Holcapek, B. Szotáková, J. Lamka, L.Skálová, J. Chromatogr. A 1149 (2007) 112-120] had described the stereospecificity of carbonyl reduction during phase I metabolic experiments in vitro. For in vivo pharmacokinetic studies, further improvement and optimization of bioanalytical HPLC method in terms of sensitivity and selectivity was necessary. Hence, a modified chiral bioanalytical HPLC method involving both UV photodiode-array and fluorescence detection for the determination of flubendazole, both enantiomers of reduced flubendazole and hydrolyzed flubendazole in the extracts from plasma samples was tested and validated. Albendazole was used as an internal standard. Sample preparation process involved a pH-dependent extraction of the analytes from the blood plasma into tert-butylmethyl ether. Chromatographic separations were performed on a Chiralcel OD-R 250 mm x 4.6mm column with mobile phase methanol-1M NaClO(4) (75:25, v/v) at the flow rate 0.5 ml min(-1). In quantitation, selective UV absorption maxima of 290 nm (for reduced flubendazole), 295 nm (for albendazole), 310 nm (for flubendazole) and 330 nm (for hydrolyzed flubendazole) were used in the UV photodiode-array detection, and lambda(exc.)/lambda(emis.)=228 nm/310 nm (for reduced flubendazole) and lambda(exc.)/lambda(emis.)=236 nm/346 nm (for albendazole) were set on the fluorescence detector. The fluorescence detection was approximately 10-times more sensitive than the UV detection. Each HPLC run lasted 27 min. The validated chiral HPLC-PDA-FL method was employed in the pharmacokinetic studies of flubendazole in sheep. The

  18. The Cherenkov Telescope Array On-Site integral sensitivity: observing the Crab

    CERN Document Server

    Fioretti, Valentina; Schussler, Fabian

    2016-01-01

    The Cherenkov Telescope Array (CTA) is the future large observatory in the very high energy (VHE) domain. Operating from 20 GeV to 300 TeV, it will be composed of tens of Imaging Air Cherenkov Telescopes (IACTs) displaced in a large area of a few square kilometers in both the southern and northern hemispheres. The CTA/DATA On-Site Analysis (OSA) is the system devoted to the development of dedicated pipelines and algorithms to be used at the CTA site for the reconstruction, data quality monitoring, science monitoring and realtime science alerting during observations. The OSA integral sensitivity is computed here for the most studied source at Gamma-rays, the Crab Nebula, for a set of exposures ranging from 1000 seconds to 50 hours, using the full CTA Southern array. The reason for the Crab Nebula selection as the first example of OSA integral sensitivity is twofold: (i) this source is characterized by a broad spectrum covering the entire CTA energy range; (ii) it represents, at the time of writing, the standar...

  19. A Supramolecular Sensor Array Using Lanthanide-Doped Nanoparticles for Sensitive Detection of Glyphosate and Proteins.

    Science.gov (United States)

    Wang, Meng; Ye, Hebo; You, Lei; Chen, Xueyuan

    2016-01-13

    Lanthanide (Ln(3+))-doped nanoparticles (NPs) are an intensive area of research in chemical and materials sciences. Herein a sensor array of Ln(3+)-doped NPs was developed for the first time toward sensitive molecular sensing based on a novel strategy of the hybridized time-resolved Förster resonance energy transfer (TR-FRET) with the indicator displacement assay (IDA) concept (TR-FRET-IDA). The sensor platform was generated in situ by binding a series of negatively charged indicators on the surface of ligand-free LiYF4:Ce/Tb NPs. The TR-FRET between NPs and dyes resulted in indicator emission and was employed as a means of removing undesired short-lived background luminescence from the indicator effectively. Displacement of indicators from the NP/indicator ensembles by glyphosate, a common herbicide, led to turn-off of the indicator emission. The sensor array was able to successfully discriminate 11 biologically relevant anions with high accuracy and sensitivity in pure aqueous buffer both qualitatively and quantitatively. Furthermore, the differentiation of six model proteins in the nM range was achieved with 100% accuracy for the classification, thereby demonstrating the versatility of this simple sensor platform. The study of the mechanism of binding and signal modulation further verified TR-FRET-IDA as a reliable sensing paradigm.

  20. Acoustic trapping with a high frequency linear phased array.

    Science.gov (United States)

    Zheng, Fan; Li, Ying; Hsu, Hsiu-Sheng; Liu, Changgeng; Tat Chiu, Chi; Lee, Changyang; Ham Kim, Hyung; Shung, K Kirk

    2012-11-19

    A high frequency ultrasonic phased array is shown to be capable of trapping and translating microparticles precisely and efficiently, made possible due to the fact that the acoustic beam produced by a phased array can be both focused and steered. Acoustic manipulation of microparticles by a phased array is advantageous over a single element transducer since there is no mechanical movement required for the array. Experimental results show that 45 μm diameter polystyrene microspheres can be easily and accurately trapped and moved to desired positions by a 64-element 26 MHz phased array.

  1. Effects of Titanium Oxide Nanotube Arrays with Different Lengths on the Characteristics of Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Chin-Guo Kuo

    2013-01-01

    Full Text Available The self-aligned highly ordered TiO2 nanotube (TNT arrays were fabricated by potentiostatic anodization of Ti foil, and we found that the TNT-array length and diameter were dependent on the electrolyte (NH4F concentration in ethylene glycol and anodization time. The characteristics of the fabricated TNT arrays were characterized by XRD pattern, FESEM, and absorption spectrum. As the electrolyte NH4F concentration in the presence of H2O (2 vol% with anodization was changed from 0.25 to 0.75 wt% and the anodization period was increased from 1 to 5 h, the TNT-array length was changed from 9.55 to 30.2 μm and the TNT-array diameter also increased. As NH4F concentration was 0.5 wt%, the prepared TNT arrays were also used to fabricate the dye-sensitized solar cells (DSSCs. We would show that the measured photovoltaic performance of the DSSCs was dependent on the TNT-array length.

  2. Photoelectrochemical cell/dye-sensitized solar cell tandem water splitting systems with transparent and vertically aligned quantum dot sensitized TiO2 nanorod arrays

    Science.gov (United States)

    Shin, Kahee; Yoo, Ji-Beom; Park, Jong Hyeok

    2013-03-01

    The present work reports fabrication of vertically aligned CdS sensitized TiO2 nanorod arrays grown on transparent conducting oxide substrate with high transparency as a photoanode in photoelectrochemical cell for water splitting. To realize an unassisted water splitting system, the photoanode and dye-sensitized solar cell tandem structures are tried and their electrochemical behaviors are also investigated. The hydrothermally grown TiO2 nanorod arrays followed by CdS nanoparticle decoration can improve the light absorption of long wavelength light resulting in increased photocurrent density. Two different techniques (electrodeposition and spray pyrolysis deposition) of CdS nanoparticle sensitization are carried out and their water splitting behaviors in the tandem cell are compared.

  3. High performance compound semiconductor SPAD arrays

    Science.gov (United States)

    Harmon, Eric S.; Naydenkov, Mikhail; Bowling, Jared

    2016-05-01

    Aggregated compound semiconductor single photon avalanche diode (SPAD) arrays are emerging as a viable alternative to the silicon photomultiplier (SiPM). Compound semiconductors have the potential to surpass SiPM performance, potentially achieving orders of magnitude lower dark count rates and improved radiation hardness. New planar processing techniques have been developed to enable compound semiconductor SPAD devices to be produced with pixel pitches of 11 - 25 microns, with thousands of SPADs per array.

  4. Sensitive and Selective Detection of HIV-1 RRE RNA Using Vertical Silicon Nanowire Electrode Array

    Science.gov (United States)

    Lee, Jaehyung; Hong, Min-Ho; Han, Sanghun; Na, Jukwan; Kim, Ilsoo; Kwon, Yong-Joon; Lim, Yong-beom; Choi, Heon-Jin

    2016-07-01

    In this study, HIV-1 Rev response element (RRE) RNA was detected via an Au-coated vertical silicon nanowire electrode array (VSNEA). The VSNEA was fabricated by combining bottom-up and top-down approaches and then immobilized by artificial peptides for the recognition of HIV-1 RRE. Differential pulse voltammetry (DPV) analysis was used to measure the electrochemical response of the peptide-immobilized VSNEA to the concentration and types of HIV-1 RRE RNA. DPV peaks showed linearity to the concentration of RNA with a detection limit down to 1.513 fM. It also showed the clear different peaks to the mutated HIV-1 RRE RNA. The high sensitivity and selectivity of VSNEA for the detection of HIV-1 RRE RNA may be attributed to the high surface-to-volume ratio and total overlap diffusion mode of ions of the one-dimensional nanowire electrodes.

  5. A 270×1 Ge-on-Si photodetector array for sensitive infrared imaging

    Science.gov (United States)

    Sammak, A.; Aminian, M.; Qi, L.; Charbon, E.; Nanver, Lis K.

    2014-05-01

    A CMOS compatible Ge photodetector (Ge-PD) fabricated on Si substrates has been shown to be suitable for near infrared (NIR) sensing; linear and avalanche detection, in both proportional and Geiger modes have been demonstrated, for photon counting at room temperature [1]. This paper focuses on implementations of the technology for the fabrication of imaging arrays of such detectors with high reproducibility and yield. The process involves selective chemical vapor deposition (CVD) of a ~ 1-μm-thick n-type Ge crystal on a Si substrate at 700°C, followed by deposition of a nm-thin Ga and B layer-stack (so-called PureGaB), all in the same deposition cycle. The PureGaB layer fulfills two functions; firstly, the Ga forms an ultrashallow p+n junction on the surface of Ge islands that allows highly sensitive NIR photodiode detection in the Ge itself; secondly, the B-layer forms a barrier that protects the Ge/Ga layers against oxidation when exposed to air and against spiking during metallization. A design for patterning the surrounding oxide is developed to ensure a uniform selective growth of the Ge crystalline islands so that the wafer surface remains flat over the whole array and any Ge nucleation on SiO2 surface is avoided. This design can deliver pixel sizes up to 30×30 μm2 with a Ge fill factor of up to 95 %. An Al metallization is used to contact each of the photodiodes to metal pads located outside the array area. A new process module has been developed for removing the Al metal on the Ge-islands to create an oxide-covered PureGaB-only front-entrance window without damaging the ultrashallow junction; thus the sensitivity to front-side illumination is maximized, especially at short wavelengths. The electrical I-V characteristics of each photodetector pixel are, to our knowledge, the best reported in literature with ideality factors of ~1.05 with Ion/Ioff ratios of 108. The uniformity is good and the yield is close to 100% over the whole array.

  6. The Cherenkov Telescope array on-site integral sensitivity: observing the Crab

    Science.gov (United States)

    Fioretti, Valentina; Bulgarelli, Andrea; Schüssler, Fabian

    2016-07-01

    The Cherenkov Telescope Array (CTA) is the future large observatory in the very high energy (VHE) domain. Operating from 20 GeV to 300 TeV, it will be composed of tens of Imaging Air Cherenkov Telescopes (IACTs) displaced in a large area of a few square kilometers in both the southern and northern hemispheres. Thanks to the wide energy coverage and the tremendous boost in effective area (10 times better than the current IACTs), for the first time a VHE observatory will be able to detect transient phenomena in short exposures. The CTA/DATA On-Site Analysis (OSA) is the system devoted to the development of dedicated pipelines and algorithms to be used at the CTA site for the reconstruction, data quality monitoring, science monitoring and realtime science alerting during observations. The minimum exposure required to issue a science alert is not a general requirement of the observatory but is a function of the astrophysical object under study, because the ability to detect a given source is determined by the integral sensitivity which, in addition to the CTA Monte Carlo simulations, providing the energy-dependent instrument response (e.g. the effective area and the background rate), requires the spectral distribution of the science target. The OSA integral sensitivity is computed here for the most studied source at Gamma-rays, the Crab Nebula, for a set of exposures ranging from 1000 seconds to 50 hours, using the full CTA Southern array. The reason for the Crab Nebula selection as the first example of OSA integral sensitivity is twofold: (i) this source is characterized by a broad spectrum covering the entire CTA energy range; (ii) it represents, at the time of writing, the standard candle in VHE and it is often used as unit for the IACTs sensitivity. The effect of different Crab Nebula emission models on the CTA integral sensitivity is evaluated, to emphasize the need for representative spectra of the CTA science targets in the evaluation of the OSA use cases. Using

  7. Highly sensitive detection of urinary cadmium to assess personal exposure

    Energy Technology Data Exchange (ETDEWEB)

    Argun, Avni A.; Banks, Ashley M.; Merlen, Gwendolynne; Tempelman, Linda A. [Giner, Inc., 89 Rumford Ave., Newton 02466, MA United States (United States); Becker, Michael F.; Schuelke, Thomas [Fraunhofer USA – CCL, 1449 Engineering Research Ct., East Lansing 48824, MI (United States); Dweik, Badawi M., E-mail: bdweik@ginerinc.com [Giner, Inc., 89 Rumford Ave., Newton 02466, MA United States (United States)

    2013-04-22

    Highlights: ► An electrochemical sensor capable of detecting cadmium at parts-per-billion levels in urine. ► A novel fabrication method for Boron-Doped Diamond (BDD) ultramicroelectrode (UME) arrays. ► Unique combination of BDD UME arrays and a differential pulse voltammetry algorithm. ► High sensitivity, high reproducibility, and very low noise levels. ► Opportunity for portable operation to assess on-site personal exposure. -- Abstract: A series of Boron-Doped Diamond (BDD) ultramicroelectrode arrays were fabricated and investigated for their performance as electrochemical sensors to detect trace level metals such as cadmium. The steady-state diffusion behavior of these sensors was validated using cyclic voltammetry followed by electrochemical detection of cadmium in water and in human urine to demonstrate high sensitivity (>200 μA ppb{sup −1} cm{sup −2}) and low background current (<4 nA). When an array of ultramicroelectrodes was positioned with optimal spacing, these BDD sensors showed a sigmoidal diffusion behavior. They also demonstrated high accuracy with linear dose dependence for quantification of cadmium in a certified reference river water sample from the U.S. National Institute of Standards and Technology (NIST) as well as in a human urine sample spiked with 0.25–1 ppb cadmium.

  8. The nuclear spectroscopic telescope array (NuSTAR) high-energy X-ray mission

    DEFF Research Database (Denmark)

    Harrison, Fiona A.; Craig, William W.; Christensen, Finn Erland

    2013-01-01

    The Nuclear Spectroscopic Telescope Array (NuSTAR) mission, launched on 2012 June 13, is the first focusing high-energy X-ray telescope in orbit. NuSTAR operates in the band from 3 to 79 keV, extending the sensitivity of focusing far beyond the ~10 keV high-energy cutoff achieved by all previous X...

  9. High sensitivity RNA pseudoknot prediction

    OpenAIRE

    Huang, Xiaolu; Ali, Hesham

    2006-01-01

    Most ab initio pseudoknot predicting methods provide very few folding scenarios for a given RNA sequence and have low sensitivities. RNA researchers, in many cases, would rather sacrifice the specificity for a much higher sensitivity for pseudoknot detection. In this study, we introduce the Pseudoknot Local Motif Model and Dynamic Partner Sequence Stacking (PLMM_DPSS) algorithm which predicts all PLM model pseudoknots within an RNA sequence in a neighboring-region-interference-free fashion. T...

  10. Enhanced Sensitivity of Surface Acoustic Wave-Based Rate Sensors Incorporating Metallic Dot Arrays

    Directory of Open Access Journals (Sweden)

    Wen Wang

    2014-02-01

    Full Text Available A new surface acoustic wave (SAW-based rate sensor pattern incorporating metallic dot arrays was developed in this paper. Two parallel SAW delay lines with a reverse direction and an operation frequency of 80 MHz on a same X-112°Y LiTaO3 wafer are fabricated as the feedback of two SAW oscillators, and mixed oscillation frequency was used to characterize the external rotation. To enhance the Coriolis force effect acting on the SAW propagation, a copper (Cu dot array was deposited along the SAW propagation path of the SAW devices. The approach of partial-wave analysis in layered media was referred to analyze the response mechanisms of the SAW based rate sensor, resulting in determination of the optimal design parameters. To improve the frequency stability of the oscillator, the single phase unidirectional transducers (SPUDTs and combed transducer were used to form the SAW device to minimize the insertion loss and accomplish the single mode selection, respectively. Excellent long-term (measured in hours frequency stability of 0.1 ppm/h was obtained. Using the rate table with high precision, the performance of the developed SAW rate sensor was evaluated experimentally; satisfactory detection sensitivity (16.7 Hz∙deg∙s−1 and good linearity were observed.

  11. Enhanced sensitivity of surface acoustic wave-based rate sensors incorporating metallic dot arrays.

    Science.gov (United States)

    Wang, Wen; Shao, Xiuting; Liu, Xinlu; Liu, Jiuling; He, Shitang

    2014-02-26

    A new surface acoustic wave (SAW)-based rate sensor pattern incorporating metallic dot arrays was developed in this paper. Two parallel SAW delay lines with a reverse direction and an operation frequency of 80 MHz on a same X-112°Y LiTaO3 wafer are fabricated as the feedback of two SAW oscillators, and mixed oscillation frequency was used to characterize the external rotation. To enhance the Coriolis force effect acting on the SAW propagation, a copper (Cu) dot array was deposited along the SAW propagation path of the SAW devices. The approach of partial-wave analysis in layered media was referred to analyze the response mechanisms of the SAW based rate sensor, resulting in determination of the optimal design parameters. To improve the frequency stability of the oscillator, the single phase unidirectional transducers (SPUDTs) and combed transducer were used to form the SAW device to minimize the insertion loss and accomplish the single mode selection, respectively. Excellent long-term (measured in hours) frequency stability of 0.1 ppm/h was obtained. Using the rate table with high precision, the performance of the developed SAW rate sensor was evaluated experimentally; satisfactory detection sensitivity (16.7 Hz∙deg∙s(-1)) and good linearity were observed.

  12. Array of chemically etched fused-silica emitters for improving the sensitivity and quantitation of electrospray ionization mass spectrometry.

    Science.gov (United States)

    Kelly, Ryan T; Page, Jason S; Tang, Keqi; Smith, Richard D

    2007-06-01

    An array of emitters has been developed for increasing the sensitivity of electrospray ionization mass spectrometry (ESI-MS). The linear array consists of 19 chemically etched fused-silica capillaries arranged with 500 microm (center-to-center) spacing. The multiemitter device has a low dead volume to facilitate coupling to capillary liquid chromatography (LC) separations. The high aspect ratio of the emitters enables operation at flow rates as low as 20 nL/min/emitter, effectively extending the benefits of nanoelectrospray to higher flow rate analyses. To accommodate the larger ion current produced by the emitter array, a multicapillary inlet to the mass spectrometer was also constructed. The inlet, which matched the dimensions of the emitter array, preserved ion transmission efficiency. Standard reserpine solutions of varying concentration were electrosprayed at 1 microL/min using the multiemitter/multi-inlet combination, and the results were compared to those from a standard, single-emitter configuration. A 9-fold sensitivity enhancement was observed for the multiemitter relative to the single emitter. A bovine serum albumin tryptic digest was also analyzed, and a sensitivity increase ranging from 2.4- to 12.3-fold for the detected tryptic peptides resulted; the varying response was attributed to reduced ion suppression under the nanoESI conditions afforded by the emitter array. An equimolar mixture of leucine enkephalin and maltopentaose was studied to verify that ion suppression is indeed reduced for the multiplexed ESI (multi-ESI) array relative to a single emitter over a range of flow rates.

  13. Fiber-coupled high resolution infrared array spectrometer for the Kuiper Airborne Observatory

    Science.gov (United States)

    Glenar, D. A.; Reuter, D.; Mumma, M. J.; Chin, G.; Wiedemann, G.; Jennings, D.

    1990-01-01

    A novel cryogenic grating spectrometer (FCAS) is being designed for observations of volatiles in cometary and planetary atmospheres, and in newly forming planetary systems. The instrument features two-dimensional detector arrays coupled to a high-dispersion echelle by infrared fibers, and will achieve a spectral resolving power of about 40,000. The primary observational platform for this instrument will be the Kuiper Airborne Observatory, but it will also be configured for use at ground-based observatories. Initially, the spectrometer will use a 58 x 62, 1- to 5-micron InSb array. Larger-format IR arrays and arrays of different composition, will later be incorporated as they become available. The instrument will be used in two modes. The first uses a large format IR array in the spectral image plane for the customary one-dimensional spectral-one-dimensional spatial coverage. In the second mode, a massive, coherent bundle of infrared transmitting ZrF4 fibers will be installed after the dispersive element, to reformat the two-dimensional array into an elongated one-dimensional array for wide spectral coverage, allowing multiple lines to be measured in a single integration with high sensitivity. The overall instrument design is discussed, and the system sensitivity is estimated.

  14. Sensitivity- and effort-gain analysis: multilead ECG electrode array selection for activation time imaging.

    Science.gov (United States)

    Hintermüller, Christoph; Seger, Michael; Pfeifer, Bernhard; Fischer, Gerald; Modre, Robert; Tilg, Bernhard

    2006-10-01

    Methods for noninvasive imaging of electric function of the heart might become clinical standard procedure the next years. Thus, the overall procedure has to meet clinical requirements as an easy and fast application. In this paper, we propose a new electrode array which improves the resolution of methods for activation time imaging considering clinical constraints such as easy to apply and compatibility with routine leads. For identifying the body-surface regions where the body surface potential (BSP) is most sensitive to changes in transmembrane potential (TMP), a virtual array method was used to compute local linear dependency (LLD) maps. The virtual array method computes a measure for the LLD in every point on the body surface. The most suitable number and position of the electrodes within the sensitive body surface regions was selected by constructing effort gain (EG) plots. Such a plot depicts the relative attainable rank of the leadfield matrix in relation to the increase in number of electrodes required to build the electrode array. The attainable rank itself was computed by a detector criterion. Such a criterion estimates the maximum number of source space eigenvectors not covered by noise when being mapped to the electrode space by the leadfield matrix and recorded by a detector. From the sensitivity maps, we found that the BSP is most sensitive to changes in TMP on the upper left frontal and dorsal body surface. These sensitive regions are covered best by an electrode array consisting of two L-shaped parts of approximately 30 cm x 30 cm and approximately 20 cm x 20 cm. The EG analysis revealed that the array meeting clinical requirements best and improving the resolution of activation time imaging consists of 125 electrodes with a regular horizontal and vertical spacing of 2-3 cm.

  15. High sensitivity RNA pseudoknot prediction.

    Science.gov (United States)

    Huang, Xiaolu; Ali, Hesham

    2007-01-01

    Most ab initio pseudoknot predicting methods provide very few folding scenarios for a given RNA sequence and have low sensitivities. RNA researchers, in many cases, would rather sacrifice the specificity for a much higher sensitivity for pseudoknot detection. In this study, we introduce the Pseudoknot Local Motif Model and Dynamic Partner Sequence Stacking (PLMM_DPSS) algorithm which predicts all PLM model pseudoknots within an RNA sequence in a neighboring-region-interference-free fashion. The PLM model is derived from the existing Pseudobase entries. The innovative DPSS approach calculates the optimally lowest stacking energy between two partner sequences. Combined with the Mfold, PLMM_DPSS can also be used in predicting complicated pseudoknots. The test results of PLMM_DPSS, PKNOTS, iterated loop matching, pknotsRG and HotKnots with Pseudobase sequences have shown that PLMM_DPSS is the most sensitive among the five methods. PLMM_DPSS also provides manageable pseudoknot folding scenarios for further structure determination.

  16. High Power Fiber Bundle Array Coupled LDA Module

    Institute of Scientific and Technical Information of China (English)

    QU Zhou; LIU Yang; ZHAO Chong-guang; WANG Ji; YIN Hong-he; WANG Li-jun

    2006-01-01

    An optical fiber bundle array coupling module with high output power is presented in this paper. The device integrated the coupling technique of the high power laser diode array (LDA) and the micro-ball lenses fiber array. This module can efficiently couple the output laser of the LDA into 19 fibers array with micro-ball lens endsurface. The difference of the couple efficiency between the flat-end fiber and micro-ball-end fiber is discussed.The micro-ball lenses fiber array made of 19 fibers have the same fiber core diameter of 200 μm, and then the endsurfaces of 19 fibers are fused to 19 micro-ball lenses. The micro-ball lenses fiber array are fixed precisely in the neighborhood on the V-grooves, and the fiber array has the same arrange period with the semiconductor laser units of LDA. This configuration of micro-ball lens fiber array can greatly reduce the divergence of the laser beam from all directions, and a very efficient laser beam homogenizer and shaper are obtained. Finally, high output power of 30.1 W of the fiber coupled LDA is achieved, and the maximal coupling efficiency is >83% with the numeral aperture (NA) of 0.16.

  17. High-resolution SNP array analysis of patients with developmental disorder and normal array CGH results

    Directory of Open Access Journals (Sweden)

    Siggberg Linda

    2012-09-01

    Full Text Available Abstract Background Diagnostic analysis of patients with developmental disorders has improved over recent years largely due to the use of microarray technology. Array methods that facilitate copy number analysis have enabled the diagnosis of up to 20% more patients with previously normal karyotyping results. A substantial number of patients remain undiagnosed, however. Methods and Results Using the Genome-Wide Human SNP array 6.0, we analyzed 35 patients with a developmental disorder of unknown cause and normal array comparative genomic hybridization (array CGH results, in order to characterize previously undefined genomic aberrations. We detected no seemingly pathogenic copy number aberrations. Most of the vast amount of data produced by the array was polymorphic and non-informative. Filtering of this data, based on copy number variant (CNV population frequencies as well as phenotypically relevant genes, enabled pinpointing regions of allelic homozygosity that included candidate genes correlating to the phenotypic features in four patients, but results could not be confirmed. Conclusions In this study, the use of an ultra high-resolution SNP array did not contribute to further diagnose patients with developmental disorders of unknown cause. The statistical power of these results is limited by the small size of the patient cohort, and interpretation of these negative results can only be applied to the patients studied here. We present the results of our study and the recurrence of clustered allelic homozygosity present in this material, as detected by the SNP 6.0 array.

  18. Mass Composition Sensitivity of an Array of Water Cherenkov and Scintillation Detectors

    CERN Document Server

    Gonzalez, Javier G; Roth, Markus

    2011-01-01

    We consider a hybrid array composed of scintillation and water Cherenkov detectors designed to measure the cosmic ray primary mass composition at energies of about 1 EeV. We have developed a simulation and reconstruction chain to study the theoretical performance of such an array. In this work we investigate the sensitivity of mass composition observables in relation to the geometry of the array. The detectors are arranged in a triangular grid with fixed 750 m spacing and the configuration of the scintillator detectors is optimized for mass composition sensitivity. We show that the performance for composition determination can be compared favorably to that of Xmax measurements after the difference in duty cycles is considered.

  19. High Density Nano-Electrode Array for Radiation Detection

    Energy Technology Data Exchange (ETDEWEB)

    Mano Misra

    2010-05-07

    Bulk single crystals of Cd1-xZnxTe (x=0.04 to x=0.2) compound semiconductor is used for room temperature radiation detection. The production of large volume of Cd1-xZnxTe with low defect density is expensive. As a result there is a growing research interest in the production of nanostructured compound semiconductors such as Cd1-xZnxTe in an electrochemical route. In this investigation, Cd1-xZnxTe ternary compound semiconductor, referred as CZT, was electrodeposited in the form of nanowires onto a TiO2 nanotubular template from propylene carbonate as the non-aqueous electrolyte, using a pulse-reverse electrodeposition process at 130 ºC. The template acted as a support in growing ordered nanowire of CZT which acts as a one dimensional conductor. Cyclic Voltammogram (CV) studies were conducted in determining the potentials for the growth of nanowires of uniform stoichiometry. The morphologies and composition of CZT were characterized by using SEM, TEM and XRD. The STEM mapping carried out on the nanowires showed the uniform distribution of Cd, Zn and Te elements. TEM image showed that the nanowires were polycrystalline in nature. The Mott-Schottky analysis carried on the nanowires showed that the nanowires were a p-type semiconductor. The carrier density, band gap and resistivity of the Cd0.9Zn0.1Te nanowires were 4.29x1013 cm-3, 1.56 eV and 2.76x1011Ω-cm respectively. The high resistivity was attributed to the presence of deep defect states such as cadmium vacancies or Te antisites which were created by the anodic cycle of the pulse-reverse electrodeposition process. Stacks of series connected CZT nanowire arrays were tested with different bias potentials. The background current was in the order of tens of picoamperes. When exposed to radiation source Amerecium-241 (60 KeV, 4 μCi), the stacked CZT nanowires arrays showed sensing behavior. The sensitivity of the nanowire arrays increased as the number of stacks increased. The preliminary results indicate that the

  20. Affordable High Performance Electromagnetically Clean Solar Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose an Electromagnetically Clean Solar Array (ECSA) with enhanced performance, in Watts/kg and Watts/m2, using flight proven, high efficiency solar cells. For...

  1. Modular Ultra-High Power Solar Array Architecture Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Deployable Space Systems, Inc. (DSS) will focus the proposed SBIR program on the development of a new highly-modularized and extremely-scalable solar array that...

  2. High sensitivity radon emanation measurements.

    Science.gov (United States)

    Zuzel, G; Simgen, H

    2009-05-01

    The presented radon detection technique employs miniaturized ultra-low background proportional counters. (222)Rn samples are purified, mixed with a counting gas and filled into a counter using a special glass vacuum line. The absolute sensitivity of the system is estimated to be 40 microBq (20 (222)Rn atoms). For emanation investigations two metal sealed stainless steel vessels and several glass vials are available. Taking into account their blank contributions, measurements at a minimum detectable activity of about 100 microBq can be performed.

  3. Transfer and assembly of large area TiO2 nanotube arrays onto conductive glass for dye sensitized solar cells

    Science.gov (United States)

    Zhang, Jun; Li, Siqian; Ding, Hao; Li, Quantong; Wang, Baoyuan; Wang, Xina; Wang, Hao

    2014-02-01

    Highly ordered titanium oxide nanotube arrays are synthesized by a two-step anodic oxidation of pure titanium foil at constant voltage. It is found that the length of nanotube arrays firstly increased rapidly with the anodization time, and then the growth rate gradually slowed down with further increasing the anodization time. The mechanism of anodization time-dependent tube length growth is discussed. Large area free-standing TiO2 nanotube (TNT) arrays are detached from the underlying Ti foil and transferred onto the fluorine-doped tin oxide (FTO) conductive glass substrates to serve as the photoanodes of the dye-sensitized solar cells (DSSCs). The photoelectric performance of the DSSCs assembled by TNT/FTO films is strongly related to the tube length of titania and the surface treatment. For the photoanodes without any surface modification, the highest overall photovoltaic conversion efficiency (PCE) that can be achieved is 4.12% in the DSSC assembled with 33-μm-thick TNT arrays, while the overall PCE of DSSC based on the 33-μm-thick TNT arrays increases to 9.02% in response to the treatment with TiCl4.

  4. Telescoping Solar Array Concept for Achieving High Packaging Efficiency

    Science.gov (United States)

    Mikulas, Martin; Pappa, Richard; Warren, Jay; Rose, Geoff

    2015-01-01

    Lightweight, high-efficiency solar arrays are required for future deep space missions using high-power Solar Electric Propulsion (SEP). Structural performance metrics for state-of-the art 30-50 kW flexible blanket arrays recently demonstrated in ground tests are approximately 40 kW/cu m packaging efficiency, 150 W/kg specific power, 0.1 Hz deployed stiffness, and 0.2 g deployed strength. Much larger arrays with up to a megawatt or more of power and improved packaging and specific power are of interest to mission planners for minimizing launch and life cycle costs of Mars exploration. A new concept referred to as the Compact Telescoping Array (CTA) with 60 kW/cu m packaging efficiency at 1 MW of power is described herein. Performance metrics as a function of array size and corresponding power level are derived analytically and validated by finite element analysis. Feasible CTA packaging and deployment approaches are also described. The CTA was developed, in part, to serve as a NASA reference solar array concept against which other proposed designs of 50-1000 kW arrays for future high-power SEP missions could be compared.

  5. A sensitive search for predicted methanol maser transitions with the Australia Telescope Compact Array

    CERN Document Server

    Chipman, Antony; Sobolev, Andrej; Cragg, Dinah

    2016-01-01

    We have used the Australia Telescope Compact Array (ATCA) to search for a number of centimetre wavelength methanol transitions which are predicted to show weak maser emission towards star formation regions. Sensitive, high spatial and spectral resolution observations towards four high-mass star formation regions which show emission in a large number of class II methanol maser transitions did not result in any detections. From these observations we are able to place an upper limit of <~1300K on the brightness temperature of any emission from the $3_1$A$^+$-$3_1$A$^-$, $17_{-2}$-$18_{-3}$E ($v_t=1$), $12_4$-$13_3$A$^-$, $12_4$-$13_3$A$^+$ and $4_1$A$^+$-$4_1$A$^-$ transitions of methanol in these sources on angular scales of 2 arcseconds. This upper limit is consistent with current models for class II methanol masers in high-mass star formation regions and better constraints than those provided here will likely require observations with next-generation radio telescopes.

  6. Preparation and properties of a phthalocyanine-sensitized TiO2 nanotube array for dye-sensitized solar cells

    Science.gov (United States)

    Cheng, Wanxi; Shen, Yue; Wu, Guizhi; Gu, Feng; Zhang, Jiancheng; Wang, Linjun

    2010-12-01

    Dye-sensitized solar cells (DSSCs) based on an ordered titanate nanotube (TNT) array were fabricated using phthalocyanine as a dye sensitizer. The ordered TNT photoanode was prepared via two steps: (1) electrosynthesis of the TiO2 nanotube array in the HF solution by the anodization method; (2) electrodeposition of 2,9,16,23-tetra-amino zinc phthalocyanine (TAZnPc) in the TiO2 nanotubes array. The morphological characteristics and structures of TAZnPc immobilized TiO2 NTs (TAZnPc/TiO2 NTs) were examined. The average pore diameter of the TNT structures was 100 nm and its average length was 500 nm. The diffuse reflection spectra (DRS) curves of TAZnPc/TiO2 NTs had a wide absorption at 550-950 nm, which may come from the TAZnPc. The photocurrent and photovoltage of the cells were measured with an active area of 0.25 cm2 by using CHI660B electrochemical workstation in the condition of illumination (AM 1.5, 100 mW cm-2). The open circuit voltage (Voc), short circuit current (Jsc) and fill factor (FF) of the DSSC are 0.416 V, 0.115 mA cm-2 and 0.68, respectively.

  7. Cryogenic High-Sensitivity Magnetometer

    Science.gov (United States)

    Day, Peter; Chui, Talso; Goodstein, David

    2005-01-01

    A proposed magnetometer for use in a cryogenic environment would be sensitive enough to measure a magnetic-flux density as small as a picogauss (10(exp -16) Tesla). In contrast, a typical conventional flux-gate magnetometer cannot measure a magnetic-flux density smaller that about 1 microgauss (10(exp -10) Tesla). One version of this device, for operation near the low end of the cryogenic temperature range, would include a piece of a paramagnetic material on a platform, the temperature of which would be controlled with a periodic variation. The variation in temperature would be measured by use of a conventional germanium resistance thermometer. A superconducting coil would be wound around the paramagnetic material and coupled to a superconducting quantum interference device (SQUID) magnetometer.

  8. Measured Sensitivity of the First Mark II Phased Array Feed on an ASKAP Antenna

    CERN Document Server

    Chippendale, A P; Beresford, R J; Hampson, G A; Macleod, A; Shaw, R D; Brothers, M L; Cantrall, C; Forsyth, A R; Hay, S G; Leach, M

    2015-01-01

    This paper presents the measured sensitivity of CSIRO's first Mk. II phased array feed (PAF) on an ASKAP antenna. The Mk. II achieves a minimum system-temperature-over-efficiency $T_\\mathrm{sys}/\\eta$ of 78 K at 1.23 GHz and is 95 K or better from 835 MHz to 1.8 GHz. This PAF was designed for the Australian SKA Pathfinder telescope to demonstrate fast astronomical surveys with a wide field of view for the Square Kilometre Array (SKA).

  9. Array of 12 coils to measure the position, alignment, and sensitivity of magnetic sensors over temperature

    Science.gov (United States)

    Husstedt, Hendrik; Ausserlechner, Udo; Kaltenbacher, Manfred

    2012-04-01

    A measurement setup is presented that allows one to determine the position, alignment, and sensitivity of magnetic sensors over temperature. To this end, an array of 12 coils is used where the number of coils is larger than the number of unknowns to increase accuracy, and to ensure an adequate measurement signal for an arbitrary orientation of the magnetic sensors. With this coil array, a 3D sensing system is analyzed which is used during the testing of automotive magnetic sensors. In particular, the influence of assembly tolerances, and the variation of temperature are examined.

  10. Sensitivity of Double-Sided Split Ring Resonator Arrays to Fabrication Tolerances

    CERN Document Server

    Trang, Frank; Rogalla, Horst; Popovic, Zoya

    2012-01-01

    We present a study of the effects of fabrication tolerances on the performance of a planar array of double-sided split-ring resonators, printed on two sides of a dielectric substrate and fabricated using a printed circuit board (PCB) milling machine. The array is simulated and measured in an X-band waveguide, and the measured resonant frequency is found to be 6.3% higher than the predicted one. The sensitivity of the frequency response to several possible fabrication and measurement errors is investigated, and the dominant effect identified and demonstrated experimentally and in simulation.

  11. Direct detection of transcription factors in cotyledons during seedling development using sensitive silicon-substrate photonic crystal protein arrays.

    Science.gov (United States)

    Jones, Sarah I; Tan, Yafang; Shamimuzzaman, Md; George, Sherine; Cunningham, Brian T; Vodkin, Lila

    2015-03-01

    Transcription factors control important gene networks, altering the expression of a wide variety of genes, including those of agronomic importance, despite often being expressed at low levels. Detecting transcription factor proteins is difficult, because current high-throughput methods may not be sensitive enough. One-dimensional, silicon-substrate photonic crystal (PC) arrays provide an alternative substrate for printing multiplexed protein microarrays that have greater sensitivity through an increased signal-to-noise ratio of the fluorescent signal compared with performing the same assay upon a traditional aminosilanized glass surface. As a model system to test proof of concept of the silicon-substrate PC arrays to directly detect rare proteins in crude plant extracts, we selected representatives of four different transcription factor families (zinc finger GATA, basic helix-loop-helix, BTF3/NAC [for basic transcription factor of the NAC family], and YABBY) that have increasing transcript levels during the stages of seedling cotyledon development. Antibodies to synthetic peptides representing the transcription factors were printed on both glass slides and silicon-substrate PC slides along with antibodies to abundant cotyledon proteins, seed lectin, and Kunitz trypsin inhibitor. The silicon-substrate PC arrays proved more sensitive than those performed on glass slides, detecting rare proteins that were below background on the glass slides. The zinc finger transcription factor was detected on the PC arrays in crude extracts of all stages of the seedling cotyledons, whereas YABBY seemed to be at the lower limit of their sensitivity. Interestingly, the basic helix-loop-helix and NAC proteins showed developmental profiles consistent with their transcript patterns, indicating proof of concept for detecting these low-abundance proteins in crude extracts.

  12. GaN Nanowire Arrays for High-Output Nanogenerators

    KAUST Repository

    Huang, Chi-Te

    2010-04-07

    Three-fold symmetrically distributed GaN nanowire (NW) arrays have been epitaxially grown on GaN/sapphire substrates. The GaN NW possesses a triangular cross section enclosed by (0001), (2112), and (2112) planes, and the angle between the GaN NW and the substrate surface is ∼62°. The GaN NW arrays produce negative output voltage pulses when scanned by a conductive atomic force microscope in contact mode. The average of piezoelectric output voltage was about -20 mV, while 5-10% of the NWs had piezoelectric output voltages exceeding -(0.15-0.35) V. The GaN NW arrays are highly stable and highly tolerate to moisture in the atmosphere. The GaN NW arrays demonstrate an outstanding potential to be utilized for piezoelectric energy generation with a performance probably better than that of ZnO NWs. © 2010 American Chemical Society.

  13. Development of fluorescent array based on sol-gel/chitosan encapsulated acetylcholinesterase and pH sensitive oxazol-5-one derivative.

    Science.gov (United States)

    Ozturk, Gulsiye; Feller, Karl-Heinz; Dornbusch, Kay; Timur, Suna; Alp, Serap; Ergun, Yavuz

    2011-01-01

    A highly sensitive fluorescent enzyme array for quantitative acetylcholine detection is developed. The enzyme array has been constructed by spotting of pH sensitive fluorophore 2-phenyl-4-[4-(1,4,7,10-tetraoxa-13-azacycloopentadecyl)benzylidene]oxazol-5-one and acetylcholinesterase doped in tetraethoxysilane/chitosan matrix via a microarrayer. The constructed tetraethoxysilane/chitosan network provided a microenvironment in which the enzyme molecule was active biologically. The optimal operational conditions for the array developed were investigated. The response of the developed biosensor array to acetylcholine was highly reproducible (RSD = 3.27%, n = 6). A good linearity was observed for acetylcholine in the concentrations up to 1 × 10(-8) M, with a detection limit of 0.27 × 10(-8) M.

  14. Nano-textured high sensitivity ion sensitive field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Hajmirzaheydarali, M.; Sadeghipari, M.; Akbari, M.; Shahsafi, A.; Mohajerzadeh, S., E-mail: mohajer@ut.ac.ir [Thin Film and Nanoelectronics Lab, Nanoelectronics Center of Excellence, School of Electrical and Computer Engineering, University of Tehran, Tehran 143957131 (Iran, Islamic Republic of)

    2016-02-07

    Nano-textured gate engineered ion sensitive field effect transistors (ISFETs), suitable for high sensitivity pH sensors, have been realized. Utilizing a mask-less deep reactive ion etching results in ultra-fine poly-Si features on the gate of ISFET devices where spacing of the order of 10 nm and less is achieved. Incorporation of these nano-sized features on the gate is responsible for high sensitivities up to 400 mV/pH in contrast to conventional planar structures. The fabrication process for this transistor is inexpensive, and it is fully compatible with standard complementary metal oxide semiconductor fabrication procedure. A theoretical modeling has also been presented to predict the extension of the diffuse layer into the electrolyte solution for highly featured structures and to correlate this extension with the high sensitivity of the device. The observed ultra-fine features by means of scanning electron microscopy and transmission electron microscopy tools corroborate the theoretical prediction.

  15. Ultra-Sensitive Colorimetric Plasmonic Sensing and Microfluidics for Biofluid Diagnostics Using Nanohole Array

    Directory of Open Access Journals (Sweden)

    Abid Ameen

    2015-01-01

    Full Text Available Colorimetric techniques provide a useful approach for sensing application because of their low cost, use of inexpensive equipment, requirement of fewer signal transduction hardware, and, above all, their simple-to-understand results. Colorimetric sensor can be used for both qualitative analyte identification as well as quantitative analysis for many application areas such as clinical diagnosis, food quality control, and environmental monitoring. A gap exists between high-end, accurate, and expensive laboratory equipment and low-cost qualitative point-of-care testing tools. Here, we present a label-free plasmonic-based colorimetric sensor fabricated on a transparent plastic substrate consisting of about one billion nanocups in an array with a subwavelength opening and decorated with metal nanoparticles on the side walls, to bridge that gap. The fabrication techniques of the plasmonic sensor, integration to portable microfluidic devices for lab on chip applications, demonstration of highly sensitive refractive-index sensing, DNA hybridization detection, and protein-protein interaction will be reviewed. Further, we anticipate that the colorimetric sensor can be applied to point-of-care diagnostics by utilizing proper surface functionalization techniques, which seems to be one of the current limiting factors. Finally, the future outlook for the colorimetric plasmonic sensors is discussed.

  16. Photolithographic Approaches for Fabricating Highly Ordered Nanopatterned Arrays

    Directory of Open Access Journals (Sweden)

    Li Xiaoru

    2008-01-01

    Full Text Available Abstract In this work, we report that large area metal nanowire and polymer nanotube arrays were successfully patterned by photolithographic approach using anodic aluminum oxide (AAO templates. Nanowires were produced by electrochemical deposition, and nanotubes by solution-wetting. The highly ordered patterns of nanowire and nanotube arrays were observed using scanning electron microscopy (SEM and found to stand free on the substrate. The method is expected to play an important role in the application of microdevices in the future.

  17. Temperature-Modulated Array High-Performance Liquid Chromatography

    OpenAIRE

    Premstaller, Andreas; Xiao, Wenzhong; Oberacher, Herbert; O'Keefe, Matthew; Stern, David; Willis, Thomas; Huber, Christian G.; Peter J. Oefner

    2001-01-01

    Using novel monolithic poly(styrene-divinylbenzene) capillary columns with an internal diameter of 0.2 mm, we demonstrate for the first time the feasibility of constructing high-performance liquid chromatography arrays for the detection of mutations by heteroduplex analysis under partially denaturing conditions. In one embodiment, such an array can be used to analyze one sample simultaneously at different temperatures to maximize the detection of mutations in DNA fragments containing multiple...

  18. On the extension of the sensitive area of an extensive air shower surface array

    CERN Document Server

    Kh, H Hedayati

    2016-01-01

    A large distance between true and reconstructed core locations of an extensive air shower (EAS) may results in great systematic mis-estimation of EAS parameters. The reconstruction of those EASs whose core locations are outside the boundary of a surface array (outside EAS (OEAS)) results in a large distance of the reconstructed core location from the true one, especially when the true core is far outside the array. Although it may not be mentioned, the identification of OEASs is a necessary and important step in the reconstruction procedure of an EAS. In this paper, an existing technique is optimized for the identification of OEASs. The simultaneous use of this technique and a recently developed approach for reconstructing the core location of an EAS can significantly increase the sensitive area of a surface array.

  19. Study on Manganin High Pressure Array Sensor

    Institute of Scientific and Technical Information of China (English)

    DUAN Jianhua; DU Xiaosong; YANG Bangchao; ZHOU Hongre

    2003-01-01

    A new kind of thin film manganin aray gauge is fabricated by adopting a new sensor fabrication technique. The sensitive materials (manganin thin films) are first deposited by magnetron sputtering on fused silica substrates, and then covered by a layer of SiO2 thin films by electron beam evaporation. Based on impedance match method of "back configuration", the highest pressure measured in Al target is 51.68 Gpa, the highest pressure in SiO2 package is 35.396 Gpa and the piezoresistance coefficient k is 0.026 Gpa-1. The upper limit and measure precision of sensor is improved.

  20. High taxonomic level fingerprint of the human intestinal microbiota by Ligase Detection Reaction - Universal Array approach

    Directory of Open Access Journals (Sweden)

    Vitali Beatrice

    2010-04-01

    Full Text Available Abstract Background Affecting the core functional microbiome, peculiar high level taxonomic unbalances of the human intestinal microbiota have been recently associated with specific diseases, such as obesity, inflammatory bowel diseases, and intestinal inflammation. Results In order to specifically monitor microbiota unbalances that impact human physiology, here we develop and validate an original DNA-microarray (HTF-Microbi.Array for the high taxonomic level fingerprint of the human intestinal microbiota. Based on the Ligase Detection Reaction-Universal Array (LDR-UA approach, the HTF-Microbi.Array enables specific detection and approximate relative quantification of 16S rRNAs from 30 phylogenetically related groups of the human intestinal microbiota. The HTF-Microbi.Array was used in a pilot study of the faecal microbiota of eight young adults. Cluster analysis revealed the good reproducibility of the high level taxonomic microbiota fingerprint obtained for each of the subject. Conclusion The HTF-Microbi.Array is a fast and sensitive tool for the high taxonomic level fingerprint of the human intestinal microbiota in terms of presence/absence of the principal groups. Moreover, analysis of the relative fluorescence intensity for each probe pair of our LDR-UA platform can provide estimation of the relative abundance of the microbial target groups within each samples. Focusing the phylogenetic resolution at division, order and cluster levels, the HTF-Microbi.Array is blind with respect to the inter-individual variability at the species level.

  1. A general technique for characterizing x-ray position sensitive arrays

    Energy Technology Data Exchange (ETDEWEB)

    Dufresne, E.; Bruning, R.; Sutton, M. [McGill Univ., Montreal, PQ (Canada). Dept. of Physics; Rodricks, B. [Argonne National Lab., IL (United States); Stephenson, G.B. [International Business Machines Corp., Yorktown Heights, NY (United States). Thomas J. Watson Research Center

    1994-03-01

    We present a general statistical technique for characterizing x-ray sensitive linear diode arrays and CCD arrays. We apply this technique to characterize the response of a linear diode array, Princeton Instrument model X-PDA, and a virtual phase CCD array, TI 4849, to direct illumination by x-rays. We find that the response of the linear array is linearly proportional to the incident intensity and uniform over its length to within 2 %. Its quantum efficiency is 38 % for Cu K{sub {alpha}} x-rays. The resolution function is evaluated from the spatial autocorrelation function and falls to 10 % of its peak value after one pixel. On the other hand, the response of the CCD detecting system to direct x-ray exposure is non-linear. To properly quantify the scattered x-rays, one must correct for the non- linearity. The resolution is two pixels along the serial transfer direction. We characterize the noise of the CCD and propose a model that takes into account the non-linearity and the resolution function to estimate the quantum efficiency of the detector. The quantum efficiency is 20 %.

  2. The Sensitivity of the Parkes Pulsar Timing Array to Individual Sources of Gravitational Waves

    CERN Document Server

    Yardley, D R B; Jenet, F A; Verbiest, J P W; Wen, Z L; Manchester, R N; Coles, W A; van Straten, W; Bailes, M; Bhat, N D R; Burke-Spolaor, S; Champion, D J; Hotan, A W; Sarkissian, J M

    2010-01-01

    We present the sensitivity of the Parkes Pulsar Timing Array to gravitational waves emitted by individual super-massive black-hole binary systems in the early phases of coalescing at the cores of merged galaxies. Our analysis includes a detailed study of the effects of fitting a pulsar timing model to non-white timing residuals. Pulsar timing is sensitive at nanoHertz frequencies and hence complementary to LIGO and LISA. We place a sky-averaged constraint on the merger rate of nearby ($z < 0.6$) black-hole binaries in the early phases of coalescence with a chirp mass of $10^{10}\\,\\rmn{M}_\\odot$ of less than one merger every seven years. The prospects for future gravitational-wave astronomy of this type with the proposed Square Kilometre Array telescope are discussed.

  3. Palladium Nanoribbon Array for Fast Hydrogen Gas Sensing with Ultrahigh Sensitivity.

    Science.gov (United States)

    Pak, Yusin; Lim, Namsoo; Kumaresan, Yogeenth; Lee, Ryeri; Kim, Kihyeun; Kim, Tae Heon; Kim, Sang-Mook; Kim, Jin Tae; Lee, Heon; Ham, Moon-Ho; Jung, Gun-Young

    2015-11-18

    A lithographically aligned palladium nano-ribbon (Pd-NRB) array with gaps of less than 40 nm is fabricated on a poly(ethylene terephthalate) substrate using the direct metal transfer method. The 200 μm Pd-NRB hydrogen gas sensor exhibits an unprecedented sensitivity of 10(9) % after bending treatment, along with fast sensing behavior (80% response time of 3.6 s and 80% recovery time of 8.7 s) at room temperature.

  4. Flexible Dye-Sensitized Solar Cell Based on Vertical ZnO Nanowire Arrays

    Directory of Open Access Journals (Sweden)

    Chu Sheng

    2011-01-01

    Full Text Available Abstract Flexible dye-sensitized solar cells are fabricated using vertically aligned ZnO nanowire arrays that are transferred onto ITO-coated poly(ethylene terephthalate substrates using a simple peel-off process. The solar cells demonstrate an energy conversion efficiency of 0.44% with good bending tolerance. This technique paves a new route for building large-scale cost-effective flexible photovoltaic and optoelectronic devices.

  5. Real-Time Analysis sensitivity evaluation of the Cherenkov Telescope Array

    CERN Document Server

    ,

    2015-01-01

    The Cherenkov Telescope Array (CTA), the new generation very high-energy gamma-ray observatory, will improve the flux sensitivity of the current Cherenkov telescopes by an order of magnitude over a continuous range from about 10 GeV to above 100 TeV. With tens of telescopes distributed in the Northern and Southern hemispheres, the large effective area and field of view coupled with the fast pointing capability make CTA a crucial instrument for the detection and understanding of the physics of transient, short-timescale variability phenomena (e.g. Gamma-Ray Bursts, Active Galactic Nuclei, gamma-ray binaries, serendipitous sources). The key CTA system for the fast identification of flaring events is the Real-Time Analysis (RTA) pipeline, a science alert system that will automatically detect and generate science alerts with a maximum latency of 30 seconds with respect to the triggering event collection and ensure fast communication to/from the astrophysics community. According to the CTA design requirements, the...

  6. Finite difference programs and array processors. [High-speed floating point processing by coupling host computer to programable array processor

    Energy Technology Data Exchange (ETDEWEB)

    Rudy, T.E.

    1977-08-01

    An alternative to maxi computers for high-speed floating-point processing capabilities is the coupling of a host computer to a programable array processor. This paper compares the performance of two finite difference programs on various computers and their expected performance on commercially available array processors. The significance of balancing array processor computation, host-array processor control traffic, and data transfer operations is emphasized. 3 figures, 1 table.

  7. Low profile conformal antenna arrays on high impedance substrate

    CERN Document Server

    Singh, Hema; Jha, Rakesh Mohan

    2016-01-01

    This book presents electromagnetic (EM) design and analysis of dipole antenna array over high impedance substrate (HIS). HIS is a preferred substrate for low-profile antenna design, owing to its unique boundary conditions. Such substrates permit radiating elements to be printed on them without any disturbance in the radiation characteristics. Moreover HIS provides improved impedance matching, enhanced bandwidth, and increased broadside directivity owing to total reflection from the reactive surface and high input impedance. This book considers different configurations of HIS for array design on planar and non-planar high-impedance surfaces. Results are presented for cylindrical dipole, printed dipole, and folded dipole over single- and double-layered square-patch-based HIS and dogbone-based HIS. The performance of antenna arrays is analyzed in terms of performance parameters such as return loss and radiation pattern. The design presented shows acceptable return loss and mainlobe gain of radiation pattern. Thi...

  8. Effect of TiO2 blocking layer on TiO2 nanorod arrays based dye sensitized solar cells

    Science.gov (United States)

    Sivakumar, R.; Paulraj, M.

    2016-05-01

    Highly ordered rutile titanium dioxide nanorod (TNR) arrays (1.2 to 6.2 μm thickness) were grown on TiO2 blocking layer chemically deposited on fluorine doped tin oxide (FTO) substrate and were used as photo-electrodes to fabricate dye sensitized solar cells (DSSC's). Homogeneous layer of TiO2 on FTO was achieved by using aqueous peroxo- titanium complex (PTC) solutions via chemical bath deposition. Structural and morphological properties of the prepared samples were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) measurements. TNR arrays (6.2 μm) with TiO2 blocking layer showed higher energy conversion efficiency (1.46%) than that without TiO2 blocking layer. The reason can be ascertained to the suppression of electron-hole recombination at the semiconductor/electrolyte interface by the effect of TiO2 blocking layer.

  9. The Telescope Array Ultra High Energy Cosmic Ray Obsrevatory

    Science.gov (United States)

    Matthews, John

    2016-07-01

    The Telescope Array measures the properties of ultra high energy cosmic ray induced extensive air showers. We do this using a variety of techniques including an array of scintillator detectors to sample the footprint of the air shower when it reaches the Earth's surface and telescopes to measure the fluorescence and Cerenkov light of the air shower. From this we determine the energy spectrum and chemical composition of the primary particles. We also search for sources of cosmic rays and anisotropy. We have found evidence of a possible source of ultra high energy cosmic rays in the northern sky. The experiment and its most recent measurements will be discussed.

  10. Sensitivity of HAWC to high-mass dark matter annihilations

    Science.gov (United States)

    Abeysekara, A. U.; Alfaro, R.; Alvarez, C.; Álvarez, J. D.; Arceo, R.; Arteaga-Velázquez, J. C.; Ayala Solares, H. A.; Barber, A. S.; Baughman, B. M.; Bautista-Elivar, N.; Becerra Gonzalez, J.; Belmont, E.; BenZvi, S. Y.; Berley, D.; Bonilla Rosales, M.; Braun, J.; Caballero-Lopez, R. A.; Caballero-Mora, K. S.; Carramiñana, A.; Castillo, M.; Cotti, U.; Cotzomi, J.; de la Fuente, E.; De León, C.; DeYoung, T.; Diaz Hernandez, R.; Diaz-Cruz, L.; Díaz-Vélez, J. C.; Dingus, B. L.; DuVernois, M. A.; Ellsworth, R. W.; Fiorino, D. W.; Fraija, N.; Galindo, A.; Garfias, F.; González, M. M.; Goodman, J. A.; Grabski, V.; Gussert, M.; Hampel-Arias, Z.; Harding, J. P.; Hui, C. M.; Hüntemeyer, P.; Imran, A.; Iriarte, A.; Karn, P.; Kieda, D.; Kunde, G. J.; Lara, A.; Lauer, R. J.; Lee, W. H.; Lennarz, D.; León Vargas, H.; Linares, E. C.; Linnemann, J. T.; Longo, M.; Luna-Garcia, R.; Marinelli, A.; Martinez, H.; Martinez, O.; Martínez-Castro, J.; Matthews, J. A. J.; McEnery, J.; Mendoza Torres, E.; Miranda-Romagnoli, P.; Moreno, E.; Mostafá, M.; Nellen, L.; Newbold, M.; Noriega-Papaqui, R.; Oceguera-Becerra, T.; Patricelli, B.; Pelayo, R.; Pérez-Pérez, E. G.; Pretz, J.; Rivière, C.; Rosa-González, D.; Ryan, J.; Salazar, H.; Salesa, F.; Sanchez, F. E.; Sandoval, A.; Schneider, M.; Silich, S.; Sinnis, G.; Smith, A. J.; Sparks Woodle, K.; Springer, R. W.; Taboada, I.; Toale, P. A.; Tollefson, K.; Torres, I.; Ukwatta, T. N.; Villaseñor, L.; Weisgarber, T.; Westerhoff, S.; Wisher, I. G.; Wood, J.; Yodh, G. B.; Younk, P. W.; Zaborov, D.; Zepeda, A.; Zhou, H.; Abazajian, K. N.; Milagro Collaboration

    2014-12-01

    The High Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view detector sensitive to gamma rays of 100 GeV to a few hundred TeV. Located in central Mexico at 19° North latitude and 4100 m above sea level, HAWC will observe gamma rays and cosmic rays with an array of water Cherenkov detectors. The full HAWC array is scheduled to be operational in Spring 2015. In this paper, we study the HAWC sensitivity to the gamma-ray signatures of high-mass (multi-TeV) dark matter annihilation. The HAWC observatory will be sensitive to diverse searches for dark matter annihilation, including annihilation from extended dark matter sources, the diffuse gamma-ray emission from dark matter annihilation, and gamma-ray emission from nonluminous dark matter subhalos. Here we consider the HAWC sensitivity to a subset of these sources, including dwarf galaxies, the M31 galaxy, the Virgo cluster, and the Galactic center. We simulate the HAWC response to gamma rays from these sources in several well-motivated dark matter annihilation channels. If no gamma-ray excess is observed, we show the limits HAWC can place on the dark matter cross section from these sources. In particular, in the case of dark matter annihilation into gauge bosons, HAWC will be able to detect a narrow range of dark matter masses to cross sections below thermal. HAWC should also be sensitive to nonthermal cross sections for masses up to nearly 1000 TeV. The constraints placed by HAWC on the dark matter cross section from known sources should be competitive with current limits in the mass range where HAWC has similar sensitivity. HAWC can additionally explore higher dark matter masses than are currently constrained.

  11. Depth of interaction resolution measurements for a high resolution PET detector using position sensitive avalanche photodiodes.

    Science.gov (United States)

    Yang, Yongfeng; Dokhale, Purushottam A; Silverman, Robert W; Shah, Kanai S; McClish, Mickel A; Farrell, Richard; Entine, Gerald; Cherry, Simon R

    2006-05-07

    We explore dual-ended read out of LSO arrays with two position sensitive avalanche photodiodes (PSAPDs) as a high resolution, high efficiency depth-encoding detector for PET applications. Flood histograms, energy resolution and depth of interaction (DOI) resolution were measured for unpolished LSO arrays with individual crystal sizes of 1.0, 1.3 and 1.5 mm, and for a polished LSO array with 1.3 mm pixels. The thickness of the crystal arrays was 20 mm. Good flood histograms were obtained for all four arrays, and crystals in all four arrays can be clearly resolved. Although the amplitude of each PSAPD signal decreases as the interaction depth moves further from the PSAPD, the sum of the two PSAPD signals is essentially constant with irradiation depth for all four arrays. The energy resolutions were similar for all four arrays, ranging from 14.7% to 15.4%. A DOI resolution of 3-4 mm (including the width of the irradiation band which is approximately 2 mm) was obtained for all the unpolished arrays. The best DOI resolution was achieved with the unpolished 1 mm array (average 3.5 mm). The DOI resolution for the 1.3 mm and 1.5 mm unpolished arrays was 3.7 and 4.0 mm respectively. For the polished array, the DOI resolution was only 16.5 mm. Summing the DOI profiles across all crystals for the 1 mm array only degraded the DOI resolution from 3.5 mm to 3.9 mm, indicating that it may not be necessary to calibrate the DOI response separately for each crystal within an array. The DOI response of individual crystals in the array confirms this finding. These results provide a detailed characterization of the DOI response of these PSAPD-based PET detectors which will be important in the design and calibration of a PET scanner making use of this detector approach.

  12. Development of high performance SWIR InGaAs focal plane array

    Science.gov (United States)

    Nagi, Richie; Bregman, Jeremy; Mizuno, Genki; Oduor, Patrick; Olah, Robert; Dutta, Achyut K.; Dhar, Nibir K.

    2015-05-01

    Banpil Photonics has developed a novel InGaAs based photodetector array for Short-Wave Infrared (SWIR) imaging, for the most demanding security, defense, and machine vision applications. These applications require low noise from both the detector and the readout integrated circuit arrays. In order to achieve high sensitivity, it is crucial to minimize the dark current generated by the photodiode array. This enables the sensor to function in extremely low light situations, which enables it to successfully exploit the benefits of the SWIR band. In addition to minimal dark current generation, it is essential to develop photodiode arrays with higher operating temperatures. This is critical for reducing the power consumption of the device, as less energy is spent in cooling down the focal plane array (in order to reduce the dark current). We at Banpil Photonics are designing, simulating, fabricating and testing SWIR InGaAs arrays, and have achieved low dark current density at room temperature. This paper describes Banpil's development of the photodetector array. We also highlight the fabrication technique used to reduce the amount of dark current generated by the photodiode array, in particular the surface leakage current. This technique involves the deposition of strongly negatively doped semiconductor material in the area between the pixels. This process reduces the number of dangling bonds present on the edges of each pixel, which prevents electrons from being swept across the surface of the pixels. This in turn drastically reduces the amount of surface leakage current at each pixel, which is a major contributor towards the total dark current. We present the optical and electrical characterization data, as well as the analysis that illustrates the dark current mechanisms. Also highlighted are the challenges and potential opportunities for further reduction of dark current, while maintaining other parameters of the photodiode array, such as size, weight, temperature

  13. High Gain Slot Array with Fabry-Perot Cavity Feeding Circuit

    Directory of Open Access Journals (Sweden)

    Halim Boutayeb

    2016-01-01

    Full Text Available A new approach for designing slot arrays using a Fabry-Perot cavity for the feeding circuit is presented. The proposed array has simpler and smaller feeding circuit compared to conventional feeding networks that have multiple dividers or combiners. The dividers and combiners are usually sources of losses. In addition, the profile of the proposed array is not limited by the half-wavelength resonance condition that exists for Fabry-Perot resonator antennas based on partially reflecting surfaces. The operating frequency is not sensitive to the profile of the antenna. A small profile can be achieved without the utilization of an artificial magnetic conductor or a substrate with high dielectric constant. To validate the proposed approach, full-wave numerical results are presented at 5.8 GHz showing good impedance matching, a high gain of about 22 dB, and an efficiency of 76%.

  14. DOA and polarization estimation via signal reconstruction with linear polarization-sensitive arrays

    Directory of Open Access Journals (Sweden)

    Liu Zhangmeng

    2015-12-01

    Full Text Available This paper addresses the problem of direction-of-arrival (DOA and polarization estimation with polarization sensitive arrays (PSA, which has been a hot topic in the area of array signal processing during the past two or three decades. The sparse Bayesian learning (SBL technique is introduced to exploit the sparsity of the incident signals in space to solve this problem and a new method is proposed by reconstructing the signals from the array outputs first and then exploiting the reconstructed signals to realize parameter estimation. Only 1-D searching and numerical calculations are contained in the proposed method, which makes the proposed method computationally much efficient. Based on a linear array consisting of identically structured sensors, the proposed method can be used with slight modifications in PSA with different polarization structures. It also performs well in the presence of coherent signals or signals with different degrees of polarization. Simulation results are given to demonstrate the parameter estimation precision of the proposed method.

  15. Ag nanoparticle-deposited TiO2 nanotube arrays for electrodes of Dye-sensitized solar cells

    Science.gov (United States)

    Kawamura, Go; Ohmi, Hayato; Tan, Wai Kian; Lockman, Zainovia; Muto, Hiroyuki; Matsuda, Atsunori

    2015-05-01

    Dye-sensitized solar cells composed of a photoanode of Ag nanoparticle (NP)-deposited TiO2 nanotube (TNT) arrays were fabricated. The TNT arrays were prepared by anodizing Ti films on fluorine-doped tin oxide (FTO)-coated glass substrates. Efficient charge transportation through the ordered nanostructure of TNT arrays should be carried out compared to conventional particulate TiO2 electrodes. However, it has been a big challenge to grow TNT arrays on FTO glass substrates with the lengths needed for sufficient light-harvesting (tens of micrometers). In this work, we deposited Ag nanoparticles (NPs) on the wall of TNT arrays to enhance light-harvesting property. Dye-sensitized solar cells with these Ag NP-deposited TNT arrays yielded a higher power conversion efficiency (2.03 %) than those without Ag NPs (1.39 %).

  16. Impact of Solar Array Designs on High Voltage Operations

    Science.gov (United States)

    Brandhorst, Henry W., Jr.; Ferguson, Dale; Piszczor, Mike; ONeill, Mark

    2006-01-01

    As power levels of advanced spacecraft climb above 25 kW, higher solar array operating voltages become attractive. Even in today s satellites, operating spacecraft buses at 100 V and above has led to arcing in GEO communications satellites, so the issue of spacecraft charging and solar array arcing remains a design problem. In addition, micrometeoroid impacts on all of these arrays can also lead to arcing if the spacecraft is at an elevated potential. For example, tests on space station hardware disclosed arcing at 75V on anodized A1 structures that were struck with hypervelocity particles in Low Earth Orbit (LEO) plasmas. Thus an understanding of these effects is necessary to design reliable high voltage solar arrays of the future, especially in light of the Vision for Space Exploration of NASA. In the future, large GEO communication satellites, lunar bases, solar electric propulsion missions, high power communication systems around Mars can lead to power levels well above 100 kW. As noted above, it will be essential to increase operating voltages of the solar arrays well above 80 V to keep the mass of cabling needed to carry the high currents to an acceptable level. Thus, the purpose of this paper is to discuss various solar array approaches, to discuss the results of testing them at high voltages, in the presence of simulated space plasma and under hypervelocity impact. Three different types of arrays will be considered. One will be a planar array using thin film cells, the second will use planar single or multijunction cells and the last will use the Stretched Lens Array (SLA - 8-fold concentration). Each of these has different approaches for protection from the space environment. The thin film cell based arrays have minimal covering due to their inherent radiation tolerance, conventional GaAs and multijunction cells have the traditional cerium-doped microsheet glasses (of appropriate thickness) that are usually attached with Dow Corning DC 93-500 silicone

  17. A 72 × 60 Angle-Sensitive SPAD Imaging Array for Lens-less FLIM

    Directory of Open Access Journals (Sweden)

    Changhyuk Lee

    2016-09-01

    Full Text Available We present a 72 × 60, angle-sensitive single photon avalanche diode (A-SPAD array for lens-less 3D fluorescence lifetime imaging. An A-SPAD pixel consists of (1 a SPAD to provide precise photon arrival time where a time-resolved operation is utilized to avoid stimulus-induced saturation, and (2 integrated diffraction gratings on top of the SPAD to extract incident angles of the incoming light. The combination enables mapping of fluorescent sources with different lifetimes in 3D space down to micrometer scale. Futhermore, the chip presented herein integrates pixel-level counters to reduce output data-rate and to enable a precise timing control. The array is implemented in standard 180 nm complementary metal-oxide-semiconductor (CMOS technology and characterized without any post-processing.

  18. Investigation on the Tunable-Length Zinc Oxide Nanowire Arrays for Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Shou-Yi Kuo

    2014-01-01

    Full Text Available We had successfully fabricated ZnO-based nanowires by vapor transport method in the furnace tube. ZnO nanowire arrays grown in 600°C for 30 minutes, 60 minutes, 90 minutes, and 120 minutes had applied to the dye-sensitized solar cells. The dye loading is proportional to the total equivalent surface area of ZnO nanowire arrays in the cells and plays an important role in improving power conversion efficiency. The highest efficiency was observed in DSSC sample with ZnO nanowires grown for 90 minutes, which had the largest equivalent surface area and also the highest dye loading. According to our experimental results, the enhancement in power conversion efficiency is attributed to the higher light harvesting and reduction of carrier recombination. In addition, ZnO nanowires also contribute to the photocurrent in the UV region.

  19. PMN-PT single-crystal high-frequency kerfless phased array.

    Science.gov (United States)

    Chen, Ruimin; Cabrera-Munoz, Nestor E; Lam, Kwok Ho; Hsu, Hsiu-sheng; Zheng, Fan; Zhou, Qifa; Shung, K Kirk

    2014-06-01

    This paper reports the design, fabrication, and characterization of a miniature high-frequency kerfless phased array prepared from a PMN-PT single crystal for forward-looking intravascular or endoscopic imaging applications. After lapping down to around 40 μm, the PMN-PT material was utilized to fabricate 32-element kerfless phased arrays using micromachining techniques. The aperture size of the active area was only 1.0 × 1.0 mm. The measured results showed that the array had a center frequency of 40 MHz, a bandwidth of 34% at -6 dB with a polymer matching layer, and an insertion loss of 20 dB at the center frequency. Phantom images were acquired and compared with simulated images. The results suggest that the feasibility of developing a phased array mounted at the tip of a forward-looking intravascular catheter or endoscope. The fabricated array exhibits much higher sensitivity than PZT ceramic-based arrays and demonstrates that PMN-PT is well suited for this application.

  20. High-power phase locking of a fiber amplifier array

    Science.gov (United States)

    Shay, T. M.; Baker, J. T.; Sanchez, A. D.; Robin, C. A.; Vergien, C. L.; Zeringue, C.; Gallant, D.; Lu, Chunte A.; Pulford, Benjamin; Bronder, T. J.; Lucero, Arthur

    2009-02-01

    We report high power phase locked fiber amplifier array using the Self-Synchronous Locking of Optical Coherence by Single-detector Electronic-frequency Tagging technique. We report the first experimental results for a five element amplifier array with a total locked power of more than 725-W. We will report on experimental measurements of the phase fluctuations versus time when the control loop is closed. The rms phase error was measured to be λ/60. Recent results will be reported. To the best of the authors' knowledge this is the highest fiber laser power to be coherently combined.

  1. A Sensor Array Using Multi-functional Field-effect Transistors with Ultrahigh Sensitivity and Precision for Bio-monitoring

    Science.gov (United States)

    Kim, Do-Il; Quang Trung, Tran; Hwang, Byeong-Ung; Kim, Jin-Su; Jeon, Sanghun; Bae, Jihyun; Park, Jong-Jin; Lee, Nae-Eung

    2015-07-01

    Mechanically adaptive electronic skins (e-skins) emulate tactition and thermoception by cutaneous mechanoreceptors and thermoreceptors in human skin, respectively. When exposed to multiple stimuli including mechanical and thermal stimuli, discerning and quantifying precise sensing signals from sensors embedded in e-skins are critical. In addition, different detection modes for mechanical stimuli, rapidly adapting (RA) and slowly adapting (SA) mechanoreceptors in human skin are simultaneously required. Herein, we demonstrate the fabrication of a highly sensitive, pressure-responsive organic field-effect transistor (OFET) array enabling both RA- and SA- mode detection by adopting easily deformable, mechano-electrically coupled, microstructured ferroelectric gate dielectrics and an organic semiconductor channel. We also demonstrate that the OFET array can separate out thermal stimuli for thermoreception during quantification of SA-type static pressure, by decoupling the input signals of pressure and temperature. Specifically, we adopt piezoelectric-pyroelectric coupling of highly crystalline, microstructured poly(vinylidene fluoride-trifluoroethylene) gate dielectric in OFETs with stimuli to allow monitoring of RA- and SA-mode responses to dynamic and static forcing conditions, respectively. This approach enables us to apply the sensor array to e-skins for bio-monitoring of humans and robotics.

  2. Ka-band MMIC microstrip array for high rate communications

    Science.gov (United States)

    Lee, R. Q.; Raquet, C. A.; Tolleson, J. B.; Sanzgiri, S. M.

    1991-01-01

    In a recent technology assessment of alternative communication systems for the space exploration initiative (SEI), Ka-band (18 to 40 GHz) communication technology was identified to meet the mission requirements of telecommunication, navigation, and information management. Compared to the lower frequency bands, Ka-band antennas offer higher gain and broader bandwidths; thus, they are more suitable for high data rate communications. Over the years, NASA has played an important role in monolithic microwave integrated circuit (MMIC) phased array technology development, and currently, has an ongoing contract with Texas Instrument (TI) to develop a modular Ka-band MMIC microstrip subarray (NAS3-25718). The TI contract emphasizes MMIC integration technology development and stipulates using existing MMIC devices to minimize the array development cost. The objective of this paper is to present array component technologies and integration techniques used to construct the subarray modules.

  3. High sensitivity knitted fabric strain sensors

    Science.gov (United States)

    Xie, Juan; Long, Hairu; Miao, Menghe

    2016-10-01

    Wearable sensors are increasingly used in smart garments for detecting and transferring vital signals and body posture, movement and respiration. Existing fabric strain sensors made from metallized yarns have low sensitivity, poor comfort and low durability to washing. Here we report a knitted fabric strain sensor made from a cotton/stainless steel (SS) fibre blended yarn which shows much higher sensitivity than sensors knitted from metallized yarns. The fabric feels softer than pure cotton textiles owing to the ultrafine stainless steel fibres and does not lose its electrical property after washing. The reason for the high sensitivity of the cotton/SS knitted fabric sensor was explored by comparing its sensing mechanism with the knitted fabric sensor made from metallized yarns. The results show that the cotton/SS yarn-to-yarn contact resistance is highly sensitive to strain applied to hooked yarn loops.

  4. Plasma Interaction with International Space Station High Voltage Solar Arrays

    Science.gov (United States)

    Heard, John W.

    2002-01-01

    The International Space Station (ISS) is presently being assembled in low-earth orbit (LEO) operating high voltage solar arrays (-160 V max, -140 V typical with respect to the ambient atmosphere). At the station's present altitude, there exists substantial ambient plasma that can interact with the solar arrays. The biasing of an object to an electric potential immersed in plasma creates a plasma "sheath" or non-equilibrium plasma around the object to mask out the electric fields. A positively biased object can collect electrons from the plasma sheath and the sheath will draw a current from the surrounding plasma. This parasitic current can enter the solar cells and effectively "short out" the potential across the cells, reducing the power that can be generated by the panels. Predictions of collected current based on previous high voltage experiments (SAMPIE (Solar Array Module Plasma Interactions Experiment), PASP+ (Photovoltaic Array Space Power) were on the order of amperes of current. However, present measurements of parasitic current are on the order of several milliamperes, and the current collection mainly occurs during an "eclipse exit" event, i.e., when the space station comes out of darkness. This collection also has a time scale, t approx. 1000 s, that is much slower than any known plasma interaction time scales. The reason for the discrepancy between predictions and present electron collection is not understood and is under investigation by the PCU (Plasma Contactor Unit) "Tiger" team. This paper will examine the potential structure within and around the solar arrays, and the possible causes and reasons for the electron collection of the array.

  5. The source of high signal cooperativity in bacterial chemosensory arrays.

    Science.gov (United States)

    Piñas, Germán E; Frank, Vered; Vaknin, Ady; Parkinson, John S

    2016-03-22

    The Escherichia coli chemosensory system consists of large arrays of transmembrane chemoreceptors associated with a dedicated histidine kinase, CheA, and a linker protein, CheW, that couples CheA activity to receptor control. The kinase activity responses to receptor ligand occupancy changes can be highly cooperative, reflecting allosteric coupling of multiple CheA and receptor molecules. Recent structural and functional studies have led to a working model in which receptor core complexes, the minimal units of signaling, are linked into hexagonal arrays through a unique interface 2 interaction between CheW and the P5 domain of CheA. To test this array model, we constructed and characterized CheA and CheW mutants with amino acid replacements at key interface 2 residues. The mutant proteins proved defective in interface 2-specific in vivo cross-linking assays, and formed signaling complexes that were dispersed around the cell membrane rather than clustered at the cell poles as in wild type chemosensory arrays. Interface 2 mutants down-regulated CheA activity in response to attractant stimuli in vivo, but with much less cooperativity than the wild type. Moreover, mutant cells containing fluorophore-tagged receptors exhibited greater basal anisotropy that changed rapidly in response to attractant stimuli, consistent with facile changes in loosely packed receptors. We conclude that interface 2 lesions disrupt important network connections between core complexes, preventing receptors from operating in large, allosteric teams. This work confirms the critical role of interface 2 in organizing the chemosensory array, in directing the clustered array to the cell poles, and in producing its highly cooperative signaling properties.

  6. High Density Planar High Temperature Superconducting Josephson Junctions Arrays

    Science.gov (United States)

    2006-09-01

    TIT,) 3 dependance . At lower temperatures it follows a (1 - T/T,)2 depen- dance ........ ................................... 57 4.7 Shapiro steps in...70 4.23 Dependance of the critical current for a ten junction array on mi- crowave power ..................................... 71 4.24 Resistance vs...GHz microwave radiation. (b) Microwave power dependance of the critical current and 1st-order Shapiro step. 76 5.2 (a) Single junction critical current

  7. High Sensitivity deflection detection of nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Sanii, Babak; Ashby, Paul

    2009-10-28

    A critical limitation of nanoelectromechanical systems (NEMS) is the lack of a high-sensitivity position detection mechanism. We introduce a noninterferometric optical approach to determine the position of nanowires with a high sensitivity and bandwidth. Its physical origins and limitations are determined by Mie scattering analysis. This enables a dramatic miniaturization of detectable cantilevers, with attendant reductions to the fundamental minimum force noise in highly damping environments. We measure the force noise of an 81{+-}9??nm radius Ag{sub 2}Ga nanowire cantilever in water at 6{+-}3??fN/{radical}Hz.

  8. Achieving ultra-high temperatures with a resistive emitter array

    Science.gov (United States)

    Danielson, Tom; Franks, Greg; Holmes, Nicholas; LaVeigne, Joe; Matis, Greg; McHugh, Steve; Norton, Dennis; Vengel, Tony; Lannon, John; Goodwin, Scott

    2016-05-01

    The rapid development of very-large format infrared detector arrays has challenged the IR scene projector community to also develop larger-format infrared emitter arrays to support the testing of systems incorporating these detectors. In addition to larger formats, many scene projector users require much higher simulated temperatures than can be generated with current technology in order to fully evaluate the performance of their systems and associated processing algorithms. Under the Ultra High Temperature (UHT) development program, Santa Barbara Infrared Inc. (SBIR) is developing a new infrared scene projector architecture capable of producing both very large format (>1024 x 1024) resistive emitter arrays and improved emitter pixel technology capable of simulating very high apparent temperatures. During earlier phases of the program, SBIR demonstrated materials with MWIR apparent temperatures in excess of 1400 K. New emitter materials have subsequently been selected to produce pixels that achieve even higher apparent temperatures. Test results from pixels fabricated using the new material set will be presented and discussed. A 'scalable' Read In Integrated Circuit (RIIC) is also being developed under the same UHT program to drive the high temperature pixels. This RIIC will utilize through-silicon via (TSV) and Quilt Packaging (QP) technologies to allow seamless tiling of multiple chips to fabricate very large arrays, and thus overcome the yield limitations inherent in large-scale integrated circuits. Results of design verification testing of the completed RIIC will be presented and discussed.

  9. Solar Array at Very High Temperatures: Ground Tests

    Science.gov (United States)

    Vayner, Boris

    2016-01-01

    Solar array design for any spacecraft is determined by the orbit parameters. For example, operational voltage for spacecraft in Low Earth Orbit (LEO) is limited by significant differential charging due to interactions with low temperature plasma. In order to avoid arcing in LEO, solar array is designed to generate electrical power at comparatively low voltages (below 100 volts) or to operate at higher voltages with encapsulation of all suspected discharge locations. In Geosynchronous Orbit (GEO) differential charging is caused by energetic electrons that produce differential potential between the coverglass and the conductive spacecraft body in a kilovolt range. In such a case, the weakly conductive layer over coverglass, indium tin oxide (ITO) is one of the possible measures to eliminate dangerous discharges on array surface. Temperature variations for solar arrays in both orbits are measured and documented within the range of minus150 degrees Centigrade to plus 1100 degrees Centigrade. This wide interval of operational temperatures is regularly reproduced in ground tests with radiative heating and cooling inside a shroud with flowing liquid nitrogen. The requirements to solar array design and tests turn out to be more complicated when planned trajectory crosses these two orbits and goes closer to the Sun. The conductive layer over coverglass causes a sharp increase in parasitic current collected from LEO plasma, high temperature may cause cracks in encapsulating (Room Temperature Vulcanizing (RTV) material; radiative heating of a coupon in vacuum chamber becomes practically impossible above 1500 degrees Centigrade; conductivities of glass and adhesive go up with temperature that decrease array efficiency; and mechanical stresses grow up to critical magnitudes. A few test arrangements and respective results are presented in current paper. Coupons were tested against arcing in simulated LEO and GEO environments under elevated temperatures up to 2000 degrees

  10. High-frequency ultrasonic arrays for ocular imaging

    Science.gov (United States)

    Jaeger, M. D.; Kline-Schoder, R. J.; Douville, G. M.; Gagne, J. R.; Morrison, K. T.; Audette, W. E.; Kynor, D. B.

    2007-03-01

    High-resolution ultrasound imaging of the anterior portion of the eye has been shown to provide important information for sizing of intraocular lens implants, diagnosis of pathological conditions, and creation of detailed maps of corneal topography to guide refractive surgery. Current ultrasound imaging systems rely on mechanical scanning of a single acoustic element over the surface of the eye to create the three-dimensional information needed by clinicians. This mechanical scanning process is time-consuming and subject to errors caused by eye movement during the scanning period. This paper describes development of linear ultrasound imaging arrays intended to increase the speed of image acquisition and reduce problems associated with ocular motion. The arrays consist of a linear arrangement of high-frequency transducer elements designed to operate in the 50 - 75 MHz frequency range. The arrays are produced using single-crystal lithium niobate piezoelectric material, thin film electrodes, and epoxy-based acoustic layers. The array elements have been used to image steel test structures and bovine cornea.

  11. Analysis of Chinese women with primary ovarian insufficiency by high resolution array-comparative genomic hybridization

    Institute of Scientific and Technical Information of China (English)

    LIAO Can; FU Fang; YANG Xin; SUN Yi-min; LI Dong-zhi

    2011-01-01

    Background Primary ovarian insufficiency (POI) is defined as a primary ovarian defect characterized by absent menarche (primary amenorrhea) or premature depletion of ovarian follicles before the age of 40 years. The etiology of primary ovarian insufficiency in human female patients is still unclear. The purpose of this study is to investigate the potential genetic causes in primary amenorrhea patients by high resolution array based comparative genomic hybridization (array-CGH) analysis.Methods Following the standard karyotyping analysis, genomic DNA from whole blood of 15 primary amenorrhea patients and 15 normal control women was hybridized with Affymetrix cytogenetic 2.7M arrays following the standard protocol. Copy number variations identified by array-CGH were confirmed by real time polymerase chain reaction.Results All the 30 samples were negative by conventional karyotyping analysis. Microdeletions on chromosome 17q21.31-q21.32 with approximately 1.3 Mb were identified in four patients by high resolution array-CGH analysis. This included the female reproductive secretory pathway related factor N-ethylmaleimide-sensitive factor (NSF) gene.Conclusions The results of the present study suggest that there may be critical regions regulating primary ovarian insufficiency in women with a 17q21.31-q21.32 microdeletion. This effect might be due to the loss of function of the NSF gene/genes within the deleted region or to effects on contiguous genes.

  12. Facile fabrication of chitosan-calcium carbonate nanowall arrays and their use as a sensitive non-enzymatic organophosphate pesticide sensor

    Science.gov (United States)

    Gong, Jingming; Zhang, Wei; Liu, Ting; Zhang, Lizhi

    2011-08-01

    Novel nanowall arrays of CaCO3-chitosan (CaCO3-chi) were deposited onto a cathodic substrate by a facile one-step electrodeposition approach. Results demonstrate that chitosan plays an important role in the formation of nanowall arrays. Freestanding well-aligned CaCO3-chi nanowall arrays were observed to be uniformly distributed over the whole substrate with a lateral dimension in the micrometre size and an average pore size of ~400 nm. The as-formed CaCO3-chi nanowall arrays featuring interlaced porous network architecture, large surface area, and open boundaries, are highly efficient in the capture of organophosphate pesticides (OPs). Combined with stripping voltammetry, a highly sensitive non-enzymatic OPs sensor was fabricated using the prepared CaCO3-chi nanowall arrays for solid phase extraction (SPE). The detection limit for methyl parathion (MP) in aqueous solutions was determined to be 0.8 ng mL-1 (S/N = 3). The resulting sensor made of novel CaCO3-chi nanowall arrays exhibits good reproducibility and acceptable stability. This work not only provides a facile and effective route for the preparation of CaCO3-chi nanowall arrays, but also offers a new promising protocol for OPs analysis.

  13. High sensitivity optically pumped quantum magnetometer.

    Science.gov (United States)

    Tiporlini, Valentina; Alameh, Kamal

    2013-01-01

    Quantum magnetometers based on optical pumping can achieve sensitivity as high as what SQUID-based devices can attain. In this paper, we discuss the principle of operation and the optimal design of an optically pumped quantum magnetometer. The ultimate intrinsic sensitivity is calculated showing that optimal performance of the magnetometer is attained with an optical pump power of 20 μW and an operation temperature of 48°C. Results show that the ultimate intrinsic sensitivity of the quantum magnetometer that can be achieved is 327 fT/Hz(½) over a bandwidth of 26 Hz and that this sensitivity drops to 130 pT/Hz(½) in the presence of environmental noise. The quantum magnetometer is shown to be capable of detecting a sinusoidal magnetic field of amplitude as low as 15 pT oscillating at 25 Hz.

  14. Fabrication of TiO2 nanoparticles/nanorod composite arrays via a two-step method for efficient dye-sensitized solar cells

    Directory of Open Access Journals (Sweden)

    Jingyang Wang

    2014-12-01

    Full Text Available TiO2 nanoparticles/nanorod composite arrays were prepared on the F-doped tin oxide (FTO substrate through a two-step method of hydrothermal and d.c. magnetron sputtering. The microstructure and optical properties of the samples were characterized respectively by means of X-ray diffraction (XRD, field-emission scanning electron microscopy (FESEM and UV–vis spectrometer. The results showed that the TiO2 composite nanorod arrays possess the nature of high surface area for more dye molecule absorption and the strong light scattering effects. The dye sensitized solar cells (DSSCs based on TiO2 composite nanorod arrays exhibited a 80% improvement in the overall energy conversion efficiency compared with the pure TiO2 nanorod arrays photoanode.

  15. Fabrication of TiO2 nanoparticles/nanorod composite arrays via a two-step method for efficient dye-sensitized solar cells

    Institute of Scientific and Technical Information of China (English)

    Jingyang Wang; Shaohua Qu; Zhicheng Zhong; Song Wang; Ke Liu; Anzheng Hu

    2014-01-01

    TiO2 nanoparticles/nanorod composite arrays were prepared on the F-doped tin oxide (FTO) substrate through a two-step method of hydrothermal and d.c. magnetron sputtering. The microstructure and optical properties of the samples were characterized respectively by means of X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and UV–vis spectrometer. The results showed that the TiO2 composite nanorod arrays possess the nature of high surface area for more dye molecule absorption and the strong light scattering effects. The dye sensitized solar cells (DSSCs) based on TiO2 composite nanorod arrays exhibited a 80%improvement in the overall energy conversion efficiency compared with the pure TiO2 nanorod arrays photoanode.

  16. Nanowire-templated microelectrodes for high-sensitivity pH detection

    DEFF Research Database (Denmark)

    Antohe, V.A.; Radu, Adrian; Mátéfi-Tempfli, Mária

    2009-01-01

    A highly sensitive pH capacitive sensor has been designed by confined growth of vertically aligned nanowire arrays on interdigited microelectrodes. The active surface of the device has been functionalized with an electrochemical pH transducer (polyaniline). We easily tune the device features...... by combining lithographic techniques with electrochemical synthesis. The reported electrical LC resonance measurements show considerable sensitivity enhancement compared to conventional capacitive pH sensors realized with microfabricated interdigited electrodes. The sensitivity can be easily improved...

  17. On-sky performance evaluation and calibration of a polarization-sensitive focal plane array

    Science.gov (United States)

    Vorobiev, Dmitry; Ninkov, Zoran; Brock, Neal; West, Ray

    2016-07-01

    The advent of pixelated micropolarizer arrays (MPAs) has facilitated the development of polarization-sensitive focal plane arrays (FPAs) based on charge-coupled devices (CCDs) and active pixel sensors (APSs), which are otherwise only able to measure the intensity of light. Polarization sensors based on MPAs are extremely compact, light-weight, mechanically robust devices with no moving parts, capable of measuring the degree and angle of polarization of light in a single snapshot. Furthermore, micropolarizer arrays based on wire grid polarizers (so called micro-grid polarizers) offer extremely broadband performance, across the optical and infrared regimes. These devices have potential for a wide array of commercial and research applications, where measurements of polarization can provide critical information, but where conventional polarimeters could be practically implemented. To date, the most successful commercial applications of these devices are 4D Technology's PhaseCam laser interferometers and PolarCam imaging polarimeters. Recently, MPA-based polarimeters have been identified as a potential solution for space-based telescopes, where the small size, snapshot capability and low power consumption (offered by these devices) are extremely desirable. In this work, we investigated the performance of MPA-based polarimeters designed for astronomical polarimetry using the Rochester Institute of Technology Polarization Imaging Camera (RITPIC). We deployed RITPIC on the 0.9 meter SMARTS telescope at the Cerro Tololo Inter-American Observatory and observed a variety of astronomical objects (calibration stars, variable stars, reflection nebulae and planetary nebulae). We use our observations to develop calibration procedures that are unique to these devices and provide an estimate for polarimetric precision that is achievable.

  18. Highly Uniform Epitaxial ZnO Nanorod Arrays for Nanopiezotronics

    Directory of Open Access Journals (Sweden)

    Nagata T

    2009-01-01

    Full Text Available Abstract Highly uniform and c-axis-aligned ZnO nanorod arrays were fabricated in predefined patterns by a low temperature homoepitaxial aqueous chemical method. The nucleation seed patterns were realized in polymer and in metal thin films, resulting in, all-ZnO and bottom-contacted structures, respectively. Both of them show excellent geometrical uniformity: the cross-sectional uniformity according to the scanning electron micrographs across the array is lower than 2%. The diameter of the hexagonal prism-shaped nanorods can be set in the range of 90–170 nm while their typical length achievable is 0.5–2.3 μm. The effect of the surface polarity was also examined, however, no significant difference was found between the arrays grown on Zn-terminated and on O-terminated face of the ZnO single crystal. The transmission electron microscopy observation revealed the single crystalline nature of the nanorods. The current–voltage characteristics taken on an individual nanorod contacted by a Au-coated atomic force microscope tip reflected Schottky-type behavior. The geometrical uniformity, the designable pattern, and the electrical properties make the presented nanorod arrays ideal candidates to be used in ZnO-based DC nanogenerator and in next-generation integrated piezoelectric nano-electromechanical systems (NEMS.

  19. Graphene-based polyaniline arrays for deoxyribonucleic acid electrochemical sensor: effect of nanostructure on sensitivity.

    Science.gov (United States)

    Yang, Tao; Meng, Le; Zhao, Jinlong; Wang, Xinxing; Jiao, Kui

    2014-01-01

    DNA detection sensitivity can be improved by carefully controlling the texture of the sensor substrate, which was normally investigated on metal or metal oxide nanostructured platform. Morphology effects on the biofunctionalization of polymer micro/nanoelectrodes have not been investigated in detail. To extend this topic, we used graphene oxide (GNO) as the supporting material to prepare graphene-based polyaniline nanocomposites with different morphologies as a model for comparing their DNA sensing behaviors. Owing to GNO serving as an excellent support or template for nucleation and growth of polyaniline (PANI), PANI nanostructures grown on GNO substrate were successfully obtained. However, if GNO supporting was absent, the obtained PANI nanowires showed a connected network. Furthermore, adjustment of reaction time can be used for dominating the topographies of PANI-GNO nanocomposites, meaning that different reaction times resulted in various formations of PANI-GNO nanocomposites, including small horns (5 and 12 h), vertical arrays (18 h), and nanotips (24 h). The next-step electrochemical data showed that the DNA electrochemical sensors constructed on the different morphologies possessed different ssDNA surface coverage and hybridization efficiency. Compared with other morphologies of PANI-GNO nanocomposite (5, 12, and 24 h), vertical arrays (18 h) exhibited the highest sensitivity (2.08 × 10(-16) M, 2 orders of magnitude lower than others). It is can be concluded that this nanocomposite with higher surface area and more accessible space can provide an optimal balance for DNA immobilization and DNA hybridization detection.

  20. Ultra-sensitive and wide-dynamic-range sensors based on dense arrays of carbon nanotube tips

    Science.gov (United States)

    Sun, Gengzhi; Huang, Yinxi; Zheng, Lianxi; Zhan, Zhaoyao; Zhang, Yani; Pang, John H. L.; Wu, Tom; Chen, Peng

    2011-11-01

    Electrochemical electrodes based on dense and vertically aligned arrays of multi-walled carbon nanotubes (MWCNTs) were produced. The open tips of individual hollow nanotubes are exposed as active sites while the entangled nanotube stems encapsulated in epoxy collectively provide multiplexed and highly conductive pathways for charge transport. This unique structure together with the extraordinary electrical and electrochemical properties of MWCNTs offers a high signal-to-noise ratio (thus high sensitivity) and a large detection range, compared with other carbon-based electrodes. Our electrodes can detect K3FeCN6 and dopamine at concentrations as low as 5 nM and 10 nM, respectively, and are responsive in a large dynamic range that spans almost 5 orders of magnitude.Electrochemical electrodes based on dense and vertically aligned arrays of multi-walled carbon nanotubes (MWCNTs) were produced. The open tips of individual hollow nanotubes are exposed as active sites while the entangled nanotube stems encapsulated in epoxy collectively provide multiplexed and highly conductive pathways for charge transport. This unique structure together with the extraordinary electrical and electrochemical properties of MWCNTs offers a high signal-to-noise ratio (thus high sensitivity) and a large detection range, compared with other carbon-based electrodes. Our electrodes can detect K3FeCN6 and dopamine at concentrations as low as 5 nM and 10 nM, respectively, and are responsive in a large dynamic range that spans almost 5 orders of magnitude. Electronic supplementary information (ESI) available. See DOI: 10.1039/c1nr10899a

  1. Stacked Polymer nanofiber array for high-performance supercapacitors

    Science.gov (United States)

    Wang, Shiren; Qiu, Jenny

    2015-03-01

    The vertically aligned polyaniline (PANI) nanowires arrays and monolayer graphene sheets were layer-by-layered deposited to specific substrate for tailored structures. Driven by external voltage, aniline molecules and graphene oxide were alternatively assembled for hierarchical porous three-dimensional nanostructures while graphene oxide was in-situ reduced to graphene during the assembly process. As-produced stacked arrays were used as the electrodes of an ultra-capacitor, and an unusual electrochemical behavior was discovered. The capacitance increases as the stack of nanowire arrays increases, resulting in high energy density and high power density at same time. Further analysis found that the distinctive electrochemical behavior originates from the electrode/electrolyte interactions and the dependence on the diffusion and charge transferring process. The specific energy density was as high as 137 Wh/Kg while power density is in excess of 2000 W/Kg. This work pointed a simple pathway to tailor polymer structure and electrochemistry for robust design of high-performance ultra-capacitor at a limited lateral size. National Science Foundation.

  2. Aluminum nanocantilevers for high sensitivity mass sensors

    DEFF Research Database (Denmark)

    Davis, Zachary James; Boisen, Anja

    2005-01-01

    We have fabricated Al nanocantilevers using a simple, one mask contact UV lithography technique with lateral and vertical dimensions under 500 and 100 nm, respectively. These devices are demonstrated as highly sensitive mass sensors by measuring their dynamic properties. Furthermore, it is shown ...

  3. Nonclassical characteristic functions for highly sensitive measurements

    CERN Document Server

    Richter, T; Richter, Th.

    2007-01-01

    Characteristic functions are shown to be useful for highly sensitive measurements. Redistributions of motional Fock states of a trapped atom can be directly monitored via the most fragile nonclassical part of the characteristic function. The method can also be used for decoherence measurements in optical quantum-information systems.

  4. High-sensitivity, high-speed continuous imaging system

    Science.gov (United States)

    Watson, Scott A; Bender, III, Howard A

    2014-11-18

    A continuous imaging system for recording low levels of light typically extending over small distances with high-frame rates and with a large number of frames is described. Photodiode pixels disposed in an array having a chosen geometry, each pixel having a dedicated amplifier, analog-to-digital convertor, and memory, provide parallel operation of the system. When combined with a plurality of scintillators responsive to a selected source of radiation, in a scintillator array, the light from each scintillator being directed to a single corresponding photodiode in close proximity or lens-coupled thereto, embodiments of the present imaging system may provide images of x-ray, gamma ray, proton, and neutron sources with high efficiency.

  5. A novel detection platform for parallel monitoring of DNA hybridization with high sensitivity and specificity

    DEFF Research Database (Denmark)

    Yi, Sun; Perch-Nielsen, Ivan R.; Wang, Zhenyu;

    We developed a high-sensitive platform to monior multiple hybridization events in real time. By creating a microoptical array in a polymeric chip, the system combine the excellent discriminative power of supercritical angle fluorescence (SAF) microscopy with high-throughput capabilities...

  6. EzArray: A web-based highly automated Affymetrix expression array data management and analysis system

    Directory of Open Access Journals (Sweden)

    Zhu Yuelin

    2008-01-01

    Full Text Available Abstract Background Though microarray experiments are very popular in life science research, managing and analyzing microarray data are still challenging tasks for many biologists. Most microarray programs require users to have sophisticated knowledge of mathematics, statistics and computer skills for usage. With accumulating microarray data deposited in public databases, easy-to-use programs to re-analyze previously published microarray data are in high demand. Results EzArray is a web-based Affymetrix expression array data management and analysis system for researchers who need to organize microarray data efficiently and get data analyzed instantly. EzArray organizes microarray data into projects that can be analyzed online with predefined or custom procedures. EzArray performs data preprocessing and detection of differentially expressed genes with statistical methods. All analysis procedures are optimized and highly automated so that even novice users with limited pre-knowledge of microarray data analysis can complete initial analysis quickly. Since all input files, analysis parameters, and executed scripts can be downloaded, EzArray provides maximum reproducibility for each analysis. In addition, EzArray integrates with Gene Expression Omnibus (GEO and allows instantaneous re-analysis of published array data. Conclusion EzArray is a novel Affymetrix expression array data analysis and sharing system. EzArray provides easy-to-use tools for re-analyzing published microarray data and will help both novice and experienced users perform initial analysis of their microarray data from the location of data storage. We believe EzArray will be a useful system for facilities with microarray services and laboratories with multiple members involved in microarray data analysis. EzArray is freely available from http://www.ezarray.com/.

  7. High blood pressure and visual sensitivity

    Science.gov (United States)

    Eisner, Alvin; Samples, John R.

    2003-09-01

    The study had two main purposes: (1) to determine whether the foveal visual sensitivities of people treated for high blood pressure (vascular hypertension) differ from the sensitivities of people who have not been diagnosed with high blood pressure and (2) to understand how visual adaptation is related to standard measures of systemic cardiovascular function. Two groups of middle-aged subjects-hypertensive and normotensive-were examined with a series of test/background stimulus combinations. All subjects met rigorous inclusion criteria for excellent ocular health. Although the visual sensitivities of the two subject groups overlapped extensively, the age-related rate of sensitivity loss was, for some measures, greater for the hypertensive subjects, possibly because of adaptation differences between the two groups. Overall, the degree of steady-state sensitivity loss resulting from an increase of background illuminance (for 580-nm backgrounds) was slightly less for the hypertensive subjects. Among normotensive subjects, the ability of a bright (3.8-log-td), long-wavelength (640-nm) adapting background to selectively suppress the flicker response of long-wavelength-sensitive (LWS) cones was related inversely to the ratio of mean arterial blood pressure to heart rate. The degree of selective suppression was also related to heart rate alone, and there was evidence that short-term changes of cardiovascular response were important. The results suggest that (1) vascular hypertension, or possibly its treatment, subtly affects visual function even in the absence of eye disease and (2) changes in blood flow affect retinal light-adaptation processes involved in the selective suppression of the flicker response from LWS cones caused by bright, long-wavelength backgrounds.

  8. Highly Energetic, Low Sensitivity Aromatic Peroxy Acids.

    Science.gov (United States)

    Gamage, Nipuni-Dhanesha H; Stiasny, Benedikt; Stierstorfer, Jörg; Martin, Philip D; Klapötke, Thomas M; Winter, Charles H

    2016-02-18

    The synthesis, structure, and energetic materials properties of a series of aromatic peroxy acid compounds are described. Benzene-1,3,5-tris(carboperoxoic) acid is a highly sensitive primary energetic material, with impact and friction sensitivities similar to those of triacetone triperoxide. By contrast, benzene-1,4-bis(carboperoxoic) acid, 4-nitrobenzoperoxoic acid, and 3,5-dinitrobenzoperoxoic acid are much less sensitive, with impact and friction sensitivities close to those of the secondary energetic material 2,4,6-trinitrotoluene. Additionally, the calculated detonation velocities of 3,5-dinitrobenzoperoxoic acid and 2,4,6-trinitrobenzoperoxoic acid exceed that of 2,4,6-trinitrotoluene. The solid-state structure of 3,5-dinitrobenzoperoxoic acid contains intermolecular O-H⋅⋅⋅O hydrogen bonds and numerous N⋅⋅⋅O, C⋅⋅⋅O, and O⋅⋅⋅O close contacts. These attractive lattice interactions may account for the less sensitive nature of 3,5-dinitrobenzoperoxoic acid.

  9. Study of the plasma interference with high voltage electrode array for space power application

    OpenAIRE

    Iwasa, Minoru; TANAKA, KOJI; Sasaki, Susumu; ODAWARA, OSAMU; 岩佐 稔; 田中 孝治; 佐々木 進; 小田原 修

    2005-01-01

    We are studying the problems associated with high voltage power systems in space. Especially we are interested in the potential distribution of the solar array that is resistant to the electrical discharge. We have carried out experiments on the interaction between the high voltage solar array and the ambient plasma. In the experiment, an array of electrodes distributed on the insulation panel was used to simulate the inter-connectors of the solar array. An electrode array without the insulat...

  10. The high granularity and large solid angle detection array EXPADES

    Energy Technology Data Exchange (ETDEWEB)

    Strano, E., E-mail: estrano@pd.infn.it [Dipartimento di Fisica e Astronomia, Università di Padova, Via Marzolo 8, I-35131 Padova (Italy); INFN – Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Anastasio, A. [INFN – Sezione di Napoli, Via Cintia, I-80126 Napoli (Italy); Bettini, M. [INFN – Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Boiano, A. [INFN – Sezione di Napoli, Via Cintia, I-80126 Napoli (Italy); Boiano, C. [INFN – Sezione di Milano, Via Celoria 16, I-20133 Milano (Italy); Cassese, C. [INFN – Sezione di Napoli, Via Cintia, I-80126 Napoli (Italy); Castellani, L.; Corti, D. [INFN – Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Di Meo, P. [INFN – Sezione di Napoli, Via Cintia, I-80126 Napoli (Italy); Galet, G. [Dipartimento di Fisica e Astronomia, Università di Padova, Via Marzolo 8, I-35131 Padova (Italy); Glodariu, T. [NIPNE, Str. Reactorului No. 30, P.O. Box MG-6, Bucharest-Magurele (Romania); Grebosz, J. [IFJ PAN, ul. Radzikowskiego 152, 31-342 Kraków (Poland); Guglielmetti, A. [Dipartimento di Fisica, Università di Milano, Via Celoria 16, I-20133 Milano (Italy); INFN – Sezione di Milano, Via Celoria 16, I-20133 Milano (Italy); La Commara, M. [Dipartimento di Scienze Fisiche, Università di Napoli, Via Cintia, I-80126 Napoli (Italy); INFN – Sezione di Napoli, Via Cintia, I-80126 Napoli (Italy); Manea, C. [INFN – Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Mazzocco, M.; Molini, P. [Dipartimento di Fisica e Astronomia, Università di Padova, Via Marzolo 8, I-35131 Padova (Italy); INFN – Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Nicoletto, M. [INFN – Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); and others

    2013-12-15

    Highlights: • We realized a detection array for Exotic Radioactive Ion Beams. • High granularity (32 × 32 pixels 2 × 2 mm wide for 8 telescopes). • High solid angle (8 telescopes 64 × 64 mm wide in a cylindrical configuration covering up to 2.6 sr). • We tested each component of the array by both alpha particles and in-beam environment. • We measured the angular distribution for {sup 17}O elastic scattering on a {sup 58}Ni target. -- Abstract: The EXPADES (EXotic PArticle DEtection System) detector array consists of 16 Double Side Silicon Strip Detectors (DSSSD) with active areas of 64 × 64 mm{sup 2}, arranged in 8 ΔE (40/50 μm)–E (300 μm) telescopes. All detector faces are segmented into 32 × 2-mm wide strips, ensuring a 2 × 2 mm{sup 2} pixel configuration. Eight ionization chambers can be alternatively used as ΔE stages or, if needed, as an additional third layer for more complex triple telescopes. The signals from silicon ΔE layers and from ionization chambers are read by standard electronics, while innovative 32-channel ASIC chips are employed for the readout of the E stages. The results of off-line tests with alpha sources and from the first in-beam experiment with a {sup 17}O beam are presented.

  11. High spatial resolution Hall sensor array for edge plasma magnetic field measurements

    Science.gov (United States)

    Liu, Yuhong; Maurer, David A.; Navratil, Gerald A.; Rivera, Nicholas

    2005-09-01

    A one-dimensional, high-spatial resolution, 20-element Hall sensor array has been developed to directly measure the edge plasma perpendicular magnetic field and its fluctuations as a function of radius with 4-mm resolution. The array employs new small-area, high-sensitivity indium antimonide (InSb) Hall probes in combination with a high-density seven-layer printed circuit board to provide for connections to supply Hall current, record the measured Hall voltage output signals, and mitigate inductive pickup. A combination of bench and in situ measurements is described that provides absolute calibration of the diagnostic array in the presence of a strong transverse magnetic field component that is approximately 1000 times greater than the perpendicular fluctuating field needed to be resolved by the diagnostic. The Hall probes calibrated using this method are capable of magnetic field measurements with a sensitivity of 7V/T over the frequency band from 0 to 20 kHz.

  12. Effect of dye-sensitized solar cells based on the anodizing TiO2 nanotube array/nanoparticle double-layer electrode

    Science.gov (United States)

    Yang, Jun Hyuk; Wung Bark, Chung; Kim, Kyung Hwan; Choi, Hyung Wook

    2014-11-01

    Highly ordered TiO2 nanotube arrays fabricated by anodization are very attractive for dye-sensitized solar cells owing to their superior charge percolation and slower charge recombination. Highly ordered, vertically aligned TiO2 nanotube arrays have been prepared by a three-step anodic oxidation. In this work, we considered the aforementioned strategies to improve the efficiency of dye-sensitized solar cells. Employing one of these approaches, the use of oxide semiconductors in the form of a TiO2 nanotube array was attempted as a novel means of improving the electron transport through the film. We fabricated a novel TiO2 nanoparticle/TiO2 nanotube array double-layer photoelectrode by a layer-by-layer assembly process, and we thoroughly investigated the effect of various structures on sample efficiency. Dye-sensitized solar cells with a light-to-electric energy conversion efficiency of 5.48% were achieved at a simulated solar light irradiation of 100 mW/cm2 (AM 1.5).

  13. Sub-array patterns of spherical-section phased array for high intensity focused ultrasound surgery

    Institute of Scientific and Technical Information of China (English)

    WANG Xiaodong; WANG Xufei; LU Mingzhu; WAN Mingxi

    2005-01-01

    The sub-array field patterns of spherical-section phased array were implemented for noninvasive ultrasound surgery of liver-tumor. The sub-array approach included field calculation, pseudo-inverse method and genetic algorithm. The sub-arrays uncovered by ribs according to scanned images normally emitted ultrasound. The results from different sub-arrays demonstrated quite satisfied acoustic performances, which included qualified focus size and intensity level for ultrasound surgery with single-focus and multi-foci patterns. Moreover, the patterns could decrease power accumulation on the ribs, and avoid damaging normal tissues. Thus the sub-array method provides a promising tool for phased array ultrasound propagating through strong obstacles like human rib cage, and it may broaden the therapeutic area, make the surgery safer and more flexible.

  14. A multi-channel femtoampere-sensitivity conductometric array for biosensing applications.

    Science.gov (United States)

    Gore, Amit; Chakrabartty, Shantanu; Pal, Sudeshna; Alocilja, Evangelyn

    2006-01-01

    Rapid detection of pathogens using field deployable biosensors requires integrated sensing and data processing. Detection of low concentration of biological agents is possible using accurate and real-time signal characterization devices. This paper presents a multi-channel conductometric array that can detect and measure current up to femtoampere range. The architecture uses a novel semi-synchronous SigmaDelta modulation that allows measurement of ultra-small currents by using a hysteretic comparison technique. The architecture achieves higher energy efficiency over a conventional SigmaDelta by reducing the total switching cycles of the comparator. A 3 mm x 3 mm chip implementing a 42 channel potentiostat array has been prototyped in a 0.5 microm CMOS technology. Measured results show 10 bits of resolution, with a sensitivity of upto 50 fA of current. The power consumption of the potentiostat is 11 microW per channel at a sampling rate of 250 kHz. The multi-channel potentiostat has been integrated with a conductometric biosensor for field deployable applications. Results with a Bacillus Cereus based biosensor demonstrate the effectiveness of the potentiostat in characterizing different concentration levels of pathogens in realtime.

  15. Highly sensitive catalytic spectrophotometric determination of ruthenium

    Science.gov (United States)

    Naik, Radhey M.; Srivastava, Abhishek; Prasad, Surendra

    2008-01-01

    A new and highly sensitive catalytic kinetic method (CKM) for the determination of ruthenium(III) has been established based on its catalytic effect on the oxidation of L-phenylalanine ( L-Pheala) by KMnO 4 in highly alkaline medium. The reaction has been followed spectrophotometrically by measuring the decrease in the absorbance at 526 nm. The proposed CKM is based on the fixed time procedure under optimum reaction conditions. It relies on the linear relationship where the change in the absorbance (Δ At) versus added Ru(III) amounts in the range of 0.101-2.526 ng ml -1 is plotted. Under the optimum conditions, the sensitivity of the proposed method, i.e. the limit of detection corresponding to 5 min is 0.08 ng ml -1, and decreases with increased time of analysis. The method is featured with good accuracy and reproducibility for ruthenium(III) determination. The ruthenium(III) has also been determined in presence of several interfering and non-interfering cations, anions and polyaminocarboxylates. No foreign ions interfered in the determination ruthenium(III) up to 20-fold higher concentration of foreign ions. In addition to standard solutions analysis, this method was successfully applied for the quantitative determination of ruthenium(III) in drinking water samples. The method is highly sensitive, selective and very stable. A review of recently published catalytic spectrophotometric methods for the determination of ruthenium(III) has also been presented for comparison.

  16. MassCode liquid arrays as a tool for multiplexed high-throughput genetic profiling.

    Directory of Open Access Journals (Sweden)

    Gregory S Richmond

    Full Text Available Multiplexed detection assays that analyze a modest number of nucleic acid targets over large sample sets are emerging as the preferred testing approach in such applications as routine pathogen typing, outbreak monitoring, and diagnostics. However, very few DNA testing platforms have proven to offer a solution for mid-plexed analysis that is high-throughput, sensitive, and with a low cost per test. In this work, an enhanced genotyping method based on MassCode technology was devised and integrated as part of a high-throughput mid-plexing analytical system that facilitates robust qualitative differential detection of DNA targets. Samples are first analyzed using MassCode PCR (MC-PCR performed with an array of primer sets encoded with unique mass tags. Lambda exonuclease and an array of MassCode probes are then contacted with MC-PCR products for further interrogation and target sequences are specifically identified. Primer and probe hybridizations occur in homogeneous solution, a clear advantage over micro- or nanoparticle suspension arrays. The two cognate tags coupled to resultant MassCode hybrids are detected in an automated process using a benchtop single quadrupole mass spectrometer. The prospective value of using MassCode probe arrays for multiplexed bioanalysis was demonstrated after developing a 14plex proof of concept assay designed to subtype a select panel of Salmonella enterica serogroups and serovars. This MassCode system is very flexible and test panels can be customized to include more, less, or different markers.

  17. Performance of terahertz metamaterials as high-sensitivity sensor

    Science.gov (United States)

    He, Yanan; Zhang, Bo; Shen, Jingling

    2017-09-01

    A high-sensitivity sensor based on the resonant transmission characteristics of terahertz (THz) metamaterials was investigated, with the proposal and fabrication of rectangular bar arrays of THz metamaterials exhibiting a period of 180 μm on a 25 μm thick flexible polyimide. Varying the size of the metamaterial structure revealed that the length of the rectangular unit modulated the resonant frequency, which was verified by both experiment and simulation. The sensing characteristics upon varying the surrounding media in the sample were tested by simulation and experiment. Changing the surrounding medium from that of air to that of alcohol or oil produced resonant frequency redshifts of 80 GHz or 150 GHz, respectively, which indicates that the sensor possessed a high sensitivity of 667 GHz per unit of refractive index. Finally, the influence of the sample substrate thickness on the sensor sensitivity was investigated by simulation. It may be a reference for future sensor design.

  18. Anti-Viral Antibody Profiling by High Density Protein Arrays

    Science.gov (United States)

    Bian, Xiaofang; Wiktor, Peter; Kahn, Peter; Brunner, Al; Khela, Amritpal; Karthikeyan, Kailash; Barker, Kristi; Yu, Xiaobo; Magee, Mitch; Wasserfall, Clive H.; Gibson, David; Rooney, Madeleine E; Qiu, Ji; LaBaer, Joshua

    2015-01-01

    Viral infections elicit anti-viral antibodies and have been associated with various chronic diseases. Detection of these antibodies can facilitate diagnosis, treatment of infection and understanding of the mechanisms of virus associated diseases. In this work, we assayed anti-viral antibodies using a novel high density-nucleic acid programmable protein array (HD-NAPPA) platform. Individual viral proteins were expressed in situ directly from plasmids encoding proteins in an array of microscopic reaction chambers. Quality of protein display and serum response was assured by comparing intra- and inter- array correlation within or between printing batches with average correlation coefficients of 0.91 and 0.96, respectively. HD-NAPPA showed higher signal to background (S/B) ratio compared with standard NAPPA on planar glass slides and ELISA. Antibody responses to 761 antigens from 25 different viruses were profiled among patients with juvenile idiopathic arthritis (JIA) and type 1 diabetes (T1D). Common as well as unique antibody reactivity patterns were detected between patients and healthy controls. We believe HD-viral-NAPPA will enable the study of host-pathogen interactions at unprecedented dimensions and elucidate the role of pathogen infections in disease development. PMID:25758251

  19. High-performance flexible supercapacitor based on porous array electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Shieh, Jen-Yu; Tsai, Sung-Ying; Li, Bo-Yan [Institute of Electro-Optical and Materials Science, National Formosa University, 64 Wenhua Road, Huwei, Yunlin 63208, Taiwan (China); Yu, Hsin Her, E-mail: hhyu@nfu.edu.tw [Department of Biotechnology, National Formosa University, 64 Wenhua Road, Huwei, Yunlin 63208, Taiwan (China)

    2017-07-01

    In this study, an array of polystyrene (PS) spheres was synthesized by a dispersion-polymerization technique as a template onto which a porous polydimethylsiloxane (PDMS) microarray structure was fabricated by soft lithography. A conducting layer was coated on the surface of the microarray after a suspension of multi-walled carbon nanotubes (MWCNTs) mixed with graphene (G) had been poured into the porous array. A PDMS-based porous supercapacitor was assembled by sandwiching a separator between two porous electrodes filled with a H{sub 3}PO{sub 4}/polyvinyl alcohol (PVA) gel electrolyte. The specific capacitance, electrochemical properties, and cycle stability of the porous electrode supercapacitors were explored. The porous PDMS-electrode-based supercapacitor exhibited high specific capacitance and good cycle stability, indicating its enormous potential for future applications in wearable and portable electronic products. - Highlights: • Porous electrode was prepared using an array of polystyrene spheres as template. • The porous electrodes provided increased contact area with the electrolyte. • A gel electrolyte averted problems with leakage and poor interfacial contact. • A larger separator pore size effectively reduced the internal resistance, iR{sub drop}. • Porous PDMS supercapacitor showed superior flexibility and cycling stability.

  20. Highly-compliant, conformal and stretchable microelectrode arrays

    Institute of Scientific and Technical Information of China (English)

    Zhang Hongzhi; Xie Lei; Yu Mei; Liu Zhiyuan; Li Yuchun; Yu Zhe

    2013-01-01

    Most biological tissues are supple and elastic,While current electronic devices fabricated by semiconductors and metals are usually stiff and brittle.As a result,implanted electronic devices can irritate and damage surrounding tissues,causing immune reaction and scarring.In this work,we develop stretchable microelectrode arrays,with the development of a novel soft lithography technology,which are designed and fabricated with a polymer/stretchable metal/polymer sandwich structure.With the great deformability of stretch,compression,bend and twisting,while preserving electrical property,this technology overcomes the fundamental mismatch of mechanical properties between biological tissues and electronic devices,and provides highly-compliant,conformal and stretchable bio-electronic interfaces.Here we also describe the following three applications of the stretchable electrode arrays:a.monitoring intracranial electroencephalography (EEG); b.stimulating peripheral nerves to drive muscles; c.monitoring epicardial electrocardiography (ECG).Stretchable microelectrode arrays create a promising field in biomedical applications for its better modulus match with biological tissues and robust mechanical and electrical properties.They allow for construction of electronic integrated circuits spread over on complex and dynamic curved surfaces,providing a much friendlier bio-electronic interface for diagnosis,treatment and intelligent bio-control.

  1. Fast, High-Precision Readout Circuit for Detector Arrays

    Science.gov (United States)

    Rider, David M.; Hancock, Bruce R.; Key, Richard W.; Cunningham, Thomas J.; Wrigley, Chris J.; Seshadri, Suresh; Sander, Stanley P.; Blavier, Jean-Francois L.

    2013-01-01

    The GEO-CAPE mission described in NASA's Earth Science and Applications Decadal Survey requires high spatial, temporal, and spectral resolution measurements to monitor and characterize the rapidly changing chemistry of the troposphere over North and South Americas. High-frame-rate focal plane arrays (FPAs) with many pixels are needed to enable such measurements. A high-throughput digital detector readout integrated circuit (ROIC) that meets the GEO-CAPE FPA needs has been developed, fabricated, and tested. The ROIC is based on an innovative charge integrating, fast, high-precision analog-to-digital circuit that is built into each pixel. The 128×128-pixel ROIC digitizes all 16,384 pixels simultaneously at frame rates up to 16 kHz to provide a completely digital output on a single integrated circuit at an unprecedented rate of 262 million pixels per second. The approach eliminates the need for off focal plane electronics, greatly reducing volume, mass, and power compared to conventional FPA implementations. A focal plane based on this ROIC will require less than 2 W of power on a 1×1-cm integrated circuit. The ROIC is fabricated of silicon using CMOS technology. It is designed to be indium bump bonded to a variety of detector materials including silicon PIN diodes, indium antimonide (InSb), indium gallium arsenide (In- GaAs), and mercury cadmium telluride (HgCdTe) detector arrays to provide coverage over a broad spectral range in the infrared, visible, and ultraviolet spectral ranges.

  2. High-sensitive cardiac troponin T

    Institute of Scientific and Technical Information of China (English)

    Ru-Yi Xu; Xiao-Fa Zhu; Ye Yang; Ping Ye

    2013-01-01

    Cardiac troponin is the preferred biomarker for the diagnosis of acute myocardial infarction (AMI). The recent development of a high-sensitive cardiac troponin T (hs-cTnT) assay permits detection of very low levels of cTnT. Using the hs-cTnT assay improves the overall diagnostic accuracy in patients with suspected AMI, while a negative result also has a high negative predictive value. The gain in sensitivity may be particularly important in patients with a short duration from symptom onset to admission. Measurement of cardiac troponin T with the hs-cTnT assay may provide strong prognostic information in patients with acute coronary syndromes, stable coronary artery disease, heart failure and even in the general population; however, increased sensitivity comes at a cost of decreased specificity. Serial testing, as well as clinical context and co-existing diseases, are likely to become increasingly important for the interpretation of hs-cTnT assay results.

  3. CdSe nanocrystal sensitized anatase TiO2 (001) tetragonal nanosheet-array films for photovoltaic application.

    Science.gov (United States)

    Feng, Shuanglong; Yang, Junyou; Liu, Ming; Liu, Yong

    2013-02-01

    CdSe nanocrystal sensitized TiO2 nanosheet array heterostructure films were fabricated by a two-step method. Firstly, a single crystalline anatase TiO2 tetragonal nanosheet-array film on a transparent conductive fluorine-doped tin oxide (FTO) substrate was successfully prepared by hydrothermal method. Then, CdSe nanocrystalline sensitizers were deposited on the TiO2 nanosheet array by CBD method. The products were characterized with XRD, SEM, TEM and UV-vis absorption spectroscopy. The effect of the CdSe nanocrystal deposition time and the length of the TiO2 sheet on the photovoltaic performance of the resulting CdSe/TiO2 nanosheet array electrodes were also investigated. In comparison with the non-sensitized TiO2 nanosheet array, the photocurrent of CdSe sensitized TiO2 nanosheet has a great enhancement, which gives some insight to the fundamental mechanism of the performance improvement.

  4. ICRF array module development and optimization for high power density

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, P.M.; Swain, D.W.

    1997-02-01

    This report describes the analysis and optimization of the proposed International Thermonuclear Experimental Reactor (ITER) Antenna Array for the ion cyclotron range of frequencies (ICRF). The objectives of this effort were to: (1) minimize the applied radiofrequency rf voltages occurring in vacuum by proper layout and shape of components, limit the component`s surface/volumes where the rf voltage is high; (2) study the effects of magnetic insulation, as applied to the current design; (3) provide electrical characteristics of the antenna for the development and analysis of tuning, arc detection/suppression, and systems for discriminating between arcs and edge-localized modes (ELMs); (4) maintain close interface with mechanical design.

  5. Optical sensitivity non-uniformity analysis and optimization of a tilt optical readout focal plane array

    Science.gov (United States)

    Fu, Jianyu; Shang, Haiping; Shi, Haitao; Li, Zhigang; Ou, Yi; Chen, Dapeng; Zhang, Qingchuan

    2016-02-01

    An optical readout focal plane array (FPA) usually has a differently tilted reflector/absorber at the initial state due to the micromachining technique. The angular deviation of the reflector/absorber has a strong impact on the optical sensitivity non-uniformity, which is a key factor which affects the imaging uniformity. In this study, a theoretical analysis has been developed, and it is found that the stress matching in SiO2-Aluminum (Al) bilayer leg could make a contribution towards reducing the optical sensitivity non-uniformity. Ion implantation of phosphorus (P) has been utilized to control the stress in SiO2 film. By controlling the implantation energy and dose, the stress and stress stability are modified. The optical readout FPA has been successfully fabricated with the stress-control technique based on P+ implantation. It is demonstrated that the gray response non-uniformity of optical readout FPA has decreased from 25.69% to 10.7%.

  6. Two Dimensional Array of Piezoresistive Nanomechanical Membrane-Type Surface Stress Sensor (MSS with Improved Sensitivity

    Directory of Open Access Journals (Sweden)

    Nico F. de Rooij

    2012-11-01

    Full Text Available We present a new generation of piezoresistive nanomechanical Membrane-type Surface stress Sensor (MSS chips, which consist of a two dimensional array of MSS on a single chip. The implementation of several optimization techniques in the design and microfabrication improved the piezoresistive sensitivity by 3~4 times compared to the first generation MSS chip, resulting in a sensitivity about ~100 times better than a standard cantilever-type sensor and a few times better than optical read-out methods in terms of experimental signal-to-noise ratio. Since the integrated piezoresistive read-out of the MSS can meet practical requirements, such as compactness and not requiring bulky and expensive peripheral devices, the MSS is a promising transducer for nanomechanical sensing in the rapidly growing application fields in medicine, biology, security, and the environment. Specifically, its system compactness due to the integrated piezoresistive sensing makes the MSS concept attractive for the instruments used in mobile applications. In addition, the MSS can operate in opaque liquids, such as blood, where optical read-out techniques cannot be applied.

  7. High-performance deployable structures for the support of high-concentration ratio solar array modules

    Science.gov (United States)

    Mobrem, M.

    1985-01-01

    A study conducted on high-performance deployable structures for the support of high-concentration ratio solar array modules is discussed. Serious consideration is being given to the use of high-concentration ratio solar array modules or applications such as space stations. These concentrator solar array designs offer the potential of reduced cost, reduced electrical complexity, higher power per unit area, and improved survivability. Arrays of concentrators, such as the miniaturized Cassegrainian concentrator modules, present a serious challenge to the structural design because their mass per unit area (5.7 kg/square meters) is higher than that of flexible solar array blankets, and the requirement for accurate orientation towards the Sun (plus or minus 0.5 degree) requires structures with improved accuracy potentials. In addition, use on a space station requires relatively high structural natural frequencies to avoid deleterious interactions with control systems and other large structural components. The objective here is to identify and evaluate conceptual designs of structures suitable for deploying and accurately supporting high-concentration ratio solar array modules.

  8. Compensated readout for high-density MOS-gated memristor crossbar array

    KAUST Repository

    Zidan, Mohammed A.

    2015-01-01

    Leakage current is one of the main challenges facing high-density MOS-gated memristor arrays. In this study, we show that leakage current ruins the memory readout process for high-density arrays, and analyze the tradeoff between the array density and its power consumption. We propose a novel readout technique and its underlying circuitry, which is able to compensate for the transistor leakage-current effect in the high-density gated memristor array.

  9. High-resolution dynamic pressure sensor array based on piezo-phototronic effect tuned photoluminescence imaging.

    Science.gov (United States)

    Peng, Mingzeng; Li, Zhou; Liu, Caihong; Zheng, Qiang; Shi, Xieqing; Song, Ming; Zhang, Yang; Du, Shiyu; Zhai, Junyi; Wang, Zhong Lin

    2015-03-24

    A high-resolution dynamic tactile/pressure display is indispensable to the comprehensive perception of force/mechanical stimulations such as electronic skin, biomechanical imaging/analysis, or personalized signatures. Here, we present a dynamic pressure sensor array based on pressure/strain tuned photoluminescence imaging without the need for electricity. Each sensor is a nanopillar that consists of InGaN/GaN multiple quantum wells. Its photoluminescence intensity can be modulated dramatically and linearly by small strain (0-0.15%) owing to the piezo-phototronic effect. The sensor array has a high pixel density of 6350 dpi and exceptional small standard deviation of photoluminescence. High-quality tactile/pressure sensing distribution can be real-time recorded by parallel photoluminescence imaging without any cross-talk. The sensor array can be inexpensively fabricated over large areas by semiconductor product lines. The proposed dynamic all-optical pressure imaging with excellent resolution, high sensitivity, good uniformity, and ultrafast response time offers a suitable way for smart sensing, micro/nano-opto-electromechanical systems.

  10. Nanopillar Arrayed Triboelectric Nanogenerator as a Self-Powered Sensitive Sensor for a Sleep Monitoring System.

    Science.gov (United States)

    Song, Weixing; Gan, Baoheng; Jiang, Tao; Zhang, Yue; Yu, Aifang; Yuan, Hongtao; Chen, Ning; Sun, Chunwen; Wang, Zhong Lin

    2016-08-23

    A flexible and low-cost triboelectric nanogenerator (TENG) based on a patterned aluminum-plastic film and an entrapped cantilever spring leaf is developed as a self-powered sensitive triboelectric sensor for sleep-body movement monitoring. The working mechanism and the impact factors of electric output performance were systematically investigated and elaborated. Due to the patterned nanostructures of the recently designed TENG, both the output voltage and current are greatly enhanced, and thereby the sensitivity of the device is significantly improved. The self-powered and sensitive device has been demonstrated as a smart body motion sensor of sleep monitoring for diagnosis of sleep disorders due to its high sensitivity and excellent stability. This work may promote the application of self-powered TENGs for healthcare and be helpful for the development of real-time mobile healthcare services and smart external portable electronics.

  11. Template fabrication of highly ordered arrays of organic semiconductor nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Heckel, Christian; Ostendorp, Stefan; Lei, Yong; Wilde, Gerhard [Institut fuer Materialphysik, Muenster (Germany)

    2011-07-01

    Porous alumina membrane (PAM) is a widely used template for the fabrication of highly ordered arrays of one-dimensional (1D) nanostructures. The structural parameters of the PAMs are adjustable, including the pore diameter and spacing, and the thickness of the membranes. And thus the structures of the 1D nanomaterials prepared using PAMs can be controlled. On the other hand, the investigation of organic semiconductors opens a new field of applications in computer technology like twistable displays or printing integrated circuits. In the current work, these two technologies are combined by depositing organic n-type semiconductors into the pores of PAMs using different synthesizing processes such as molecular evaporation and solution-phase self-assembly. As a result, highly ordered arrays of organic semiconducting wires are obtained within the pores with a diameter of about 50 nm, which indicates that it is possible to fill the pores with organic materials.The properties of these ''filled'' membranes are characterized by measuring the electrical properties of several nanowires pooled together and also of single nanowires by AFM-based methods.

  12. High-resolution ionization detector and array of such detectors

    Energy Technology Data Exchange (ETDEWEB)

    McGregor, Douglas S. (Ypsilanti, MI); Rojeski, Ronald A. (Pleasanton, CA)

    2001-01-16

    A high-resolution ionization detector and an array of such detectors are described which utilize a reference pattern of conductive or semiconductive material to form interaction, pervious and measurement regions in an ionization substrate of, for example, CdZnTe material. The ionization detector is a room temperature semiconductor radiation detector. Various geometries of such a detector and an array of such detectors produce room temperature operated gamma ray spectrometers with relatively high resolution. For example, a 1 cm.sup.3 detector is capable of measuring .sup.137 Cs 662 keV gamma rays with room temperature energy resolution approaching 2% at FWHM. Two major types of such detectors include a parallel strip semiconductor Frisch grid detector and the geometrically weighted trapezoid prism semiconductor Frisch grid detector. The geometrically weighted detector records room temperature (24.degree. C.) energy resolutions of 2.68% FWHM for .sup.137 Cs 662 keV gamma rays and 2.45% FWHM for .sup.60 Co 1.332 MeV gamma rays. The detectors perform well without any electronic pulse rejection, correction or compensation techniques. The devices operate at room temperature with simple commercially available NIM bin electronics and do not require special preamplifiers or cooling stages for good spectroscopic results.

  13. Experimental study on high-voltage solar array sustained arc discharge induced by high charging

    Institute of Scientific and Technical Information of China (English)

    LI Kai; XIE ErQing; WANG Li; LIU YanXia; YANG Yang; SUN YanZheng; CUI XinYu; MAI ShengLi

    2007-01-01

    It has been reported that sustained arc discharge induced by electrostatic discharge (ESD) could cause permanent damage to high-power and high-voltage solar array of spacecrafts. The paper focuses on ESD simulating experiments on Si and GaAs samples, and induces sustained arc discharge. The physical mechanism of sustained arc discharge is discussed by comparing the charging/discharging phenomena between Si and GaAs samples. The experiments show that sustained arc discharge can produce a permanent short-circuit channel between solar cell strings through which the solar array's photovoltaic power may flow out sustainedly. The analyses show that sustained arc discharge strongly depends on solar array structure, solar array operating voltage, ESD characteristics and cell materials.

  14. Digital array gas radiometer (DAGR): a sensitive and reliable trace gas detection concept

    Science.gov (United States)

    Gordley, Larry L.; McHugh, Martin J.; Marshall, B. T.; Thompson, Earl

    2009-05-01

    The Digital Array Gas Radiometer (DAGR) concept is based on traditional and reliable Gas Filter Correlation Radiometry (GFCR) for remote trace gas detection and monitoring. GFCR sensors have been successful in many infrared remote sensing applications. Historically however, solar backscatter measurements have not been as successful because instrument designs have been susceptible to natural variations in surface albedo, which induce clutter and degrade the sensitivity. DAGR overcomes this limitation with several key innovations. First, a pupil imaging system scrambles the received light, removing nearly all spatial clutter and permitting a small calibration source to be easily inserted. Then, by using focal plane arrays rather than single detectors to collect the light, dramatic advances in dynamic range can be achieved. Finally, when used with the calibration source, data processing approaches can further mitigate detector non-uniformity effects. DAGR sensors can be made as small as digital cameras and are well suited for downlooking detection of gases in the boundary layer, where solar backscatter measurements are needed to overcome the lack of thermal contrast in the IR. Easily integrated into a satellite platform, a space-based DAGR would provide near-global sensing of climatically important species such as such as CO, CH4, and N2O. Aircraft and UAV measurements with a DAGR could be used to monitor agricultural and industrial emissions. Ground-based or portable DAGRs could augment early warning systems for chemical weapons or toxic materials. Finally, planetary science applications include detection and mapping of biomarkers such as CH4 in the Martian atmosphere.

  15. Photodetector having high speed and sensitivity

    Science.gov (United States)

    Morse, Jeffrey D.; Mariella, Jr., Raymond P.

    1991-01-01

    The present invention provides a photodetector having an advantageous combination of sensitivity and speed; it has a high sensitivity while retaining high speed. In a preferred embodiment, visible light is detected, but in some embodiments, x-rays can be detected, and in other embodiments infrared can be detected. The present invention comprises a photodetector having an active layer, and a recombination layer. The active layer has a surface exposed to light to be detected, and comprises a semiconductor, having a bandgap graded so that carriers formed due to interaction of the active layer with the incident radiation tend to be swept away from the exposed surface. The graded semiconductor material in the active layer preferably comprises Al.sub.1-x Ga.sub.x As. An additional sub-layer of graded In.sub.1-y Ga.sub.y As may be included between the Al.sub.1-x Ga.sub.x As layer and the recombination layer. The recombination layer comprises a semiconductor material having a short recombination time such as a defective GaAs layer grown in a low temperature process. The recombination layer is positioned adjacent to the active layer so that carriers from the active layer tend to be swept into the recombination layer. In an embodiment, the photodetector may comprise one or more additional layers stacked below the active and recombination layers. These additional layers may include another active layer and another recombination layer to absorb radiation not absorbed while passing through the first layers. A photodetector having a stacked configuration may have enhanced sensitivity and responsiveness at selected wavelengths such as infrared.

  16. Examination of measurement and its method of compensation of the sensitivity distribution using phased array coil for body scan

    CERN Document Server

    Kimura, T; Iizuka, A; Taniguchi, Y; Ishikuro, A; Hongo, T; Inoue, H; Ogura, A

    2003-01-01

    The influence on the quality of images by measurement of a sensitivity distribution and the use of a sensitivity compensation filter was considered using an opposite-type phased array coil and volume-type phased array coil. With the opposite-type phased array coil, the relation between coil interval and filter was investigated for the image intensity correction (IIC) filter, surface coil intensity correction (SCIC) filter (GE), and the Normalize filter (SIEMENS). The SCIC filter and Normalize filter showed distance dependability over the coil interval of signal-to-noise ratio (SNR) and uniformity was observed, and the existence of an optimal coil interval was suggested. Moreover, with the IIC filter, distance dependability over a coil interval was small, and the decrease in contrast with use was remarkable. On the other hand, with the volume-type phased array coil, the overlap of an array element was investigated to determine the influence it had on sensitivity distribution. Although the value stabilized in t...

  17. Genome-wide mapping of copy number variation in humans: comparative analysis of high resolution array platforms.

    Directory of Open Access Journals (Sweden)

    Rajini R Haraksingh

    Full Text Available Accurate and efficient genome-wide detection of copy number variants (CNVs is essential for understanding human genomic variation, genome-wide CNV association type studies, cytogenetics research and diagnostics, and independent validation of CNVs identified from sequencing based technologies. Numerous, array-based platforms for CNV detection exist utilizing array Comparative Genome Hybridization (aCGH, Single Nucleotide Polymorphism (SNP genotyping or both. We have quantitatively assessed the abilities of twelve leading genome-wide CNV detection platforms to accurately detect Gold Standard sets of CNVs in the genome of HapMap CEU sample NA12878, and found significant differences in performance. The technologies analyzed were the NimbleGen 4.2 M, 2.1 M and 3×720 K Whole Genome and CNV focused arrays, the Agilent 1×1 M CGH and High Resolution and 2×400 K CNV and SNP+CGH arrays, the Illumina Human Omni1Quad array and the Affymetrix SNP 6.0 array. The Gold Standards used were a 1000 Genomes Project sequencing-based set of 3997 validated CNVs and an ultra high-resolution aCGH-based set of 756 validated CNVs. We found that sensitivity, total number, size range and breakpoint resolution of CNV calls were highest for CNV focused arrays. Our results are important for cost effective CNV detection and validation for both basic and clinical applications.

  18. High sensitivity troponin and valvular heart disease.

    Science.gov (United States)

    McCarthy, Cian P; Donnellan, Eoin; Phelan, Dermot; Griffin, Brian P; Sarano, Maurice Enriquez-; McEvoy, John W

    2017-01-16

    Blood-based biomarkers have been extensively studied in a range of cardiovascular diseases and have established utility in routine clinical care, most notably in the diagnosis of acute coronary syndrome (e.g., troponin) and the management of heart failure (e.g., brain-natriuretic peptide). The role of biomarkers is less well established in the management of valvular heart disease (VHD), in which the optimal timing of surgical intervention is often challenging. One promising biomarker that has been the subject of a number of recent VHD research studies is high sensitivity troponin (hs-cTn). Novel high-sensitivity assays can detect subclinical myocardial damage in asymptomatic individuals. Thus, hs-cTn may have utility in the assessment of asymptomatic patients with severe VHD who do not have a clear traditional indication for surgical intervention. In this state-of-the-art review, we examine the current evidence for hs-cTn as a potential biomarker in the most commonly encountered VHD conditions, aortic stenosis and mitral regurgitation. This review provides a synopsis of early evidence indicating that hs-cTn has promise as a biomarker in VHD. However, the impact of its measurement on clinical practice and VHD outcomes needs to be further assessed in prospective studies before routine clinical use becomes a reality.

  19. Characterization of a highly-segmented silicon prototype for the TRACE array

    Directory of Open Access Journals (Sweden)

    Gelain M.

    2014-03-01

    Full Text Available In view of the construction of novel and high-sensitive instrumentation for the emerging ISOL facilities new prototypes have being implemented and tested. The contribution focuses at the investigation of the detection efficiency of an innovative silicon-pad prototype, which is the key element for the construction of the TRACE array, pursued for the SPES facility based at the Legnaro National Laboratories (Italy. The inter-pad size has been estimated by using a commercial 100-MHz-14-bit CAEN digitizer for sampling the signals obtained by an alpha-source scan over the inter-pad region.

  20. Solid-state dye-sensitized solar cells based on ZnO nanoparticle and nanorod array hybrid photoanodes

    Directory of Open Access Journals (Sweden)

    Sue Hung-Jue

    2011-01-01

    Full Text Available Abstract The effect of ZnO photoanode morphology on the performance of solid-state dye-sensitized solar cells (DSSCs is reported. Four different structures of dye-loaded ZnO layers have been fabricated in conjunction with poly(3-hexylthiophene. A significant improvement in device efficiency with ZnO nanorod arrays as photoanodes has been achieved by filling the interstitial voids of the nanorod arrays with ZnO nanoparticles. The overall power conversion efficiency increases from 0.13% for a nanorod-only device to 0.34% for a device with combined nanoparticles and nanorod arrays. The higher device efficiency in solid-state DSSCs with hybrid nanorod/nanoparticle photoanodes is originated from both large surface area provided by nanoparticles for dye adsorption and efficient charge transport provided by the nanorod arrays to reduce the recombinations of photogenerated carriers.

  1. Development Toward a Ground-Based Interferometric Phased Array for Radio Detection of High Energy Neutrinos

    CERN Document Server

    Avva, J; Chesebro, T; Cremonisi, L; Deaconu, C; Gupta, A; Ludwig, A; Messino, W; Miki, C; Nichol, R; Oberla, E; Romero-Wolf, A; Saltzberg, D; Schlupf, C; Shipp, N; Varner, G; Vieregg, A G; Wissel, S A

    2016-01-01

    A promising method for further measurements of high energy neutrinos at the PeV scale and above is through an in-ice radio interferometric phased array, designed to look for Askaryan emission from neutrinos interacting in large volumes of glacial ice. Such a detector would be sensitive to two populations of neutrinos: the PeV-scale astrophysical neutrino flux recently detected by IceCube, and the predicted cosmogenic ultra-high energy (UHE) flux ($E>10^{17}$ eV). Characterizing these high energy neutrino populations is an important step toward understanding the most energetic cosmic accelerators, and the discovery of UHE neutrinos would allow us to probe fundamental physics at energy scales that are not achievable on Earth. We report here on studies validating the phased array technique, including measurements and a simulation of thermal noise correlations between nearby antennas, beamforming for impulsive signals, and a measurement of the expected improvement in trigger efficiency through the phased array te...

  2. Innovative nanostructures for highly sensitive vibrational biosensing (Conference Presentation)

    Science.gov (United States)

    Popp, Juergen; Mayerhöfer, Thomas; Cialla-May, Dana; Weber, Karina; Huebner, Uwe

    2016-03-01

    Employing vibrational spectroscopy (IR-absorption and Raman spectroscopy) allows for the labelfree detection of molecular specific fingerprints of inorganic, organic and biological substances. The sensitivity of vibrational spectroscopy can be improved by several orders of magnitude via the application of plasmonic active surfaces. Within this contribution we will discuss two such approaches, namely surface enhanced Raman spectroscopy (SERS) as well as surface enhanced IR absorption (SEIRA). It will be shown that SERS using metal colloids as SERS active substrate in combination with a microfluidic lab-on-a-chip (LOC) device enables high throughput and reproducible measurements with highest sensitivity and specificity. The application of such a LOC-SERS approach for therapeutic drug monitoring (e.g. quantitative detection of antibiotics in a urine matrix) will be presented. Furthermore, we will introduce innovative bottom-up strategies to prepare SERS-active nanostructures coated with a lipophilic sensor layer as one-time use SERS substrates for specific food analysis (e.g. quantitative detection of toxic food colorants). The second part of this contribution presents a slit array metamaterial perfect absorber for IR sensing applications consisting of a dielectric layer sandwiched between two metallic layers of which the upper layer is perforated with a periodic array of slits. Light-matter interaction is greatly amplified in the slits, where also the analyte is concentrated, as the surface of the substrate is covered by a thin silica layer. Thus, already small concentrations of analytes down to a monolayer can be detected by refractive index sensing and identified by their spectral fingerprints with a standard mid-infrared lab spectrometer.

  3. High Gain and High Directive of Antenna Arrays Utilizing Dielectric Layer on Bismuth Titanate Ceramics

    Directory of Open Access Journals (Sweden)

    F. H. Wee

    2012-01-01

    Full Text Available A high gain and high directive microstrip patch array antenna formed from dielectric layer stacked on bismuth titanate (BiT ceramics have been investigated, fabricated, and measured. The antennas are designed and constructed with a combination of two-, four-, and six-BiT elements in an array form application on microwave substrate. For gain and directivity enhancement, a layer of dielectric was stacked on the BiT antenna array. We measured the gain and directivity of BiT array antennas with and without the dielectric layer and found that the gain of BiT array antenna with the dielectric layer was enhanced by about 1.4 dBi of directivity and 1.3 dB of gain over the one without the dielectric layer at 2.3 GHz. The impedance bandwidth of the BiT array antenna both with and without the dielectric layer is about 500 MHz and 350 MHz, respectively, which is suitable for the application of the WiMAX 2.3 GHz system. The utilization of BiT ceramics that covers about 90% of antenna led to high radiation efficiency, and small-size antennas were produced. In order to validate the proposed design, theoretical and measured results are provided and discussed.

  4. High efficiency micro solar cells integrated with lens array

    Science.gov (United States)

    Fidaner, Onur; Suarez, Ferran A.; Wiemer, Michael; Sabnis, Vijit A.; Asano, Tetsuya; Itou, Akihiro; Inoue, Daijiro; Hayashi, Nobuhiko; Arase, Hidekazu; Matsushita, Akio; Nakagawa, Tohru

    2014-03-01

    We demonstrate high efficiency triple junction solar cells with submillimeter dimensions in an all-back-contact architecture. 550 × 550 μm2 cells flash at 41.3% efficiency under the air mass 1.5 direct normal spectrum at 50 W/cm2 at 25 °C. Compared to standard size production cells, the micro cells have reduced performance at 1-sun due to perimeter recombination, but the performance gap closes at higher concentrations. Micro cells integrated with lens arrays were tested on-sun with an efficiency of 34.7%. All-back-contact architecture and submillimeter dimensions are advantageous for module integration and heat dissipation, allowing for high-performance, compact, lightweight, and cost-effective concentrated photovoltaic modules.

  5. Reverse Phase Protein Arrays for High-throughput Toxicity Screening

    DEFF Research Database (Denmark)

    Pedersen, Marlene Lemvig; Block, Ines; List, Markus

    High-throughput screening is extensively applied for identification of drug targets and drug discovery and recently it found entry into toxicity testing. Reverse phase protein arrays (RPPAs) are used widespread for quantification of protein markers. We reasoned that RPPAs also can be utilized...... beneficially in automated high-throughput toxicity testing. An advantage of using RPPAs is that, in addition to the baseline toxicity readout, they allow testing of multiple markers of toxicity, such as inflammatory responses, which do not necessarily cumulate in cell death. We used transfection of si...... a robotic screening platform. Furthermore, we automated sample tracking and data analysis by developing a bundled bioinformatics tool named “MIRACLE”. Automation and RPPA-based viability/toxicity readouts enable rapid testing of large sample numbers, while granting the possibility for flexible consecutive...

  6. Study of the interaction between space plasma and high voltage solar array

    OpenAIRE

    Iwasa, Minoru; TANAKA, KOJI; Sasaki, Susumu; ODAWARA, OSAMU; 岩佐 稔; 田中 孝治; 佐々木 進; 小田原 修

    2006-01-01

    We are studying the problems associated with high voltage power systems in space. Especially we are interested in the potential distribution of the solar array that is resistant to the electrical discharge. We have carried out experiment on the interaction between the space plasma and the high voltage solar array. An array of electrodes distributed on a dielectric material was used to simulate the inter-connectors of the solar array panel in space environment. One of major concerns in the usa...

  7. Dendritic Heterojunction Nanowire Arrays for High-Performance Supercapacitors

    Science.gov (United States)

    Zou, Rujia; Zhang, Zhenyu; Yuen, Muk Fung; Hu, Junqing; Lee, Chun-Sing; Zhang, Wenjun

    2015-01-01

    Herein, we designed and synthesized for the first time a series of 3D dendritic heterojunction arrays on Ni foam substrates, with NiCo2S4 nanowires as cores and NiCo2O4, NiO, Co3O4, and MnO2 nanowires as branches, and studied systematically their electrochemical performance in comparison with their counterparts in core/shell structure. Attributed to the following reasons: (1) both core and branch are pseudocapacitively active materials, (2) the special dendritic structure with considerable inter-nanowire space enables easy access of electrolyte to the core and branch surfaces, and (3) the highly conductive NiCo2S4 nanowire cores provide ``superhighways'' for charge transition, NiCo2S4-cored dendritic heterojunction electrodes synergistically lead to ultrahigh specific capacitance, good rate capability, and excellent cycling life. These results of core/branch dentritic heterojunction arrays is universially superior to their core/shell conterparts, thus this is a significant improvement of overall electrochemical performance.

  8. Crystallographic alignment of high-density gallium nitride nanowire arrays.

    Science.gov (United States)

    Kuykendall, Tevye; Pauzauskie, Peter J; Zhang, Yanfeng; Goldberger, Joshua; Sirbuly, Donald; Denlinger, Jonathan; Yang, Peidong

    2004-08-01

    Single-crystalline, one-dimensional semiconductor nanostructures are considered to be one of the critical building blocks for nanoscale optoelectronics. Elucidation of the vapour-liquid-solid growth mechanism has already enabled precise control over nanowire position and size, yet to date, no reports have demonstrated the ability to choose from different crystallographic growth directions of a nanowire array. Control over the nanowire growth direction is extremely desirable, in that anisotropic parameters such as thermal and electrical conductivity, index of refraction, piezoelectric polarization, and bandgap may be used to tune the physical properties of nanowires made from a given material. Here we demonstrate the use of metal-organic chemical vapour deposition (MOCVD) and appropriate substrate selection to control the crystallographic growth directions of high-density arrays of gallium nitride nanowires with distinct geometric and physical properties. Epitaxial growth of wurtzite gallium nitride on (100) gamma-LiAlO(2) and (111) MgO single-crystal substrates resulted in the selective growth of nanowires in the orthogonal [1\\[Evec]0] and [001] directions, exhibiting triangular and hexagonal cross-sections and drastically different optical emission. The MOCVD process is entirely compatible with the current GaN thin-film technology, which would lead to easy scale-up and device integration.

  9. High taxonomic level fingerprint of the human intestinal microbiota by ligase detection reaction--universal array approach.

    Science.gov (United States)

    Candela, Marco; Consolandi, Clarissa; Severgnini, Marco; Biagi, Elena; Castiglioni, Bianca; Vitali, Beatrice; De Bellis, Gianluca; Brigidi, Patrizia

    2010-04-19

    Affecting the core functional microbiome, peculiar high level taxonomic unbalances of the human intestinal microbiota have been recently associated with specific diseases, such as obesity, inflammatory bowel diseases, and intestinal inflammation. In order to specifically monitor microbiota unbalances that impact human physiology, here we develop and validate an original DNA-microarray (HTF-Microbi.Array) for the high taxonomic level fingerprint of the human intestinal microbiota. Based on the Ligase Detection Reaction-Universal Array (LDR-UA) approach, the HTF-Microbi.Array enables specific detection and approximate relative quantification of 16S rRNAs from 30 phylogenetically related groups of the human intestinal microbiota. The HTF-Microbi.Array was used in a pilot study of the faecal microbiota of eight young adults. Cluster analysis revealed the good reproducibility of the high level taxonomic microbiota fingerprint obtained for each of the subject. The HTF-Microbi.Array is a fast and sensitive tool for the high taxonomic level fingerprint of the human intestinal microbiota in terms of presence/absence of the principal groups. Moreover, analysis of the relative fluorescence intensity for each probe pair of our LDR-UA platform can provide estimation of the relative abundance of the microbial target groups within each samples. Focusing the phylogenetic resolution at division, order and cluster levels, the HTF-Microbi.Array is blind with respect to the inter-individual variability at the species level.

  10. Highly Sensitive Electro-Optic Modulators

    Energy Technology Data Exchange (ETDEWEB)

    DeVore, Peter S [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-26

    There are very important diagnostic and communication applications that receive faint electrical signals to be transmitted over long distances for capture. Optical links reduce bandwidth and distance restrictions of metal transmission lines; however, such signals are only weakly imprinted onto the optical carrier, resulting in low fidelity transmission. Increasing signal fidelity often necessitates insertion of radio-frequency (RF) amplifiers before the electro-optic modulator, but (especially at high frequencies) RF amplification results in large irreversible distortions. We have investigated the feasibility of a Sensitive and Linear Modulation by Optical Nonlinearity (SALMON) modulator to supersede RF-amplified modulators. SALMON uses cross-phase modulation, a manifestation of the Kerr effect, to enhance the modulation depth of an RF-modulated optical wave. This ultrafast process has the potential to result in less irreversible distortions as compared to a RF-amplified modulator due to the broadband nature of the Kerr effect. Here, we prove that a SALMON modulator is a feasible alternative to an RFamplified modulator, by demonstrating a sensitivity enhancement factor greater than 20 and significantly reduced distortion.

  11. Integrated multi-ISE arrays with improved sensitivity, accuracy and precision

    Science.gov (United States)

    Wang, Chunling; Yuan, Hongyan; Duan, Zhijuan; Xiao, Dan

    2017-03-01

    Increasing use of ion-selective electrodes (ISEs) in the biological and environmental fields has generated demand for high-sensitivity ISEs. However, improving the sensitivities of ISEs remains a challenge because of the limit of the Nernstian slope (59.2/n mV). Here, we present a universal ion detection method using an electronic integrated multi-electrode system (EIMES) that bypasses the Nernstian slope limit of 59.2/n mV, thereby enabling substantial enhancement of the sensitivity of ISEs. The results reveal that the response slope is greatly increased from 57.2 to 1711.3 mV, 57.3 to 564.7 mV and 57.7 to 576.2 mV by electronic integrated 30 Cl‑ electrodes, 10 F‑ electrodes and 10 glass pH electrodes, respectively. Thus, a tiny change in the ion concentration can be monitored, and correspondingly, the accuracy and precision are substantially improved. The EIMES is suited for all types of potentiometric sensors and may pave the way for monitoring of various ions with high accuracy and precision because of its high sensitivity.

  12. Coherent beam combining architectures for high power tapered laser arrays

    Science.gov (United States)

    Schimmel, G.; Janicot, S.; Hanna, M.; Decker, J.; Crump, P.; Erbert, G.; Witte, U.; Traub, M.; Georges, P.; Lucas-Leclin, G.

    2017-02-01

    Coherent beam combining (CBC) aims at increasing the spatial brightness of lasers. It consists in maintaining a constant phase relationship between different emitters, in order to combine them constructively in one single beam. We have investigated the CBC of an array of five individually-addressable high-power tapered laser diodes at λ = 976 nm, in two architectures: the first one utilizes the self-organization of the lasers in an interferometric extended-cavity, which ensures their mutual coherence; the second one relies on the injection of the emitters by a single-frequency laser diode. In both cases, the coherent combining of the phase-locked beams is ensured on the front side of the array by a transmission diffractive grating with 98% efficiency. The passive phase-locking of the laser bar is obtained up to 5 A (per emitter). An optimization algorithm is implemented to find the proper currents in the five ridge sections that ensured the maximum combined power on the front side. Under these conditions we achieve a maximum combined power of 7.5 W. In the active MOPA configuration, we can increase the currents in the tapered sections up to 6 A and get a combined power of 11.5 W, corresponding to a combining efficiency of 76%. It is limited by the beam quality of the tapered emitters and by fast phase fluctuations between emitters. Still, these results confirm the potential of CBC approaches with tapered lasers to provide a high-power and high-brightness beam, and compare with the current state-of-the-art with laser diodes.

  13. Heterogeneous catalysis in highly sensitive microreactors

    DEFF Research Database (Denmark)

    Olsen, Jakob Lind

    This thesis present a highly sensitive silicon microreactor and examples of its use in studying catalysis. The experimental setup built for gas handling and temperature control for the microreactor is described. The implementation of LabVIEW interfacing for all the experimental parts makes...... automated experiments and data collection possible. An argon ush at the O-rings (used to interface the silicon microreactor with the gas system), which was developed, is presented. It enables experiments with temperatures up to 400., and up to 500. for short periods of time. The CO oxidation reaction...... of adsorbates readily converted to methanol as the source of the transient increase in methanol production, is eliminated. A study of mass selected ruthenium nanoparticles from a magnetron-sputter gas-aggregation source, deposited in microreactors, is presented. It is, shown that CO methanation can be measured...

  14. High-sensitivity fiber optic acoustic sensors

    Science.gov (United States)

    Lu, Ping; Liu, Deming; Liao, Hao

    2016-11-01

    Due to the overwhelming advantages compared with traditional electronicsensors, fiber-optic acoustic sensors have arisen enormous interest in multiple disciplines. In this paper we present the recent research achievements of our group on fiber-optic acoustic sensors. The main point of our research is high sensitivity interferometric acoustic sensors, including Michelson, Sagnac, and Fabry-Pérot interferometers. In addition, some advanced technologies have been proposed for acoustic or acoustic pressure sensing such as single-mode/multimode fiber coupler, dual FBGs and multi-longitudinal mode fiber laser based acoustic sensors. Moreover, our attention we have also been paid on signal demodulation schemes. The intensity-based quadrature point (Q-point) demodulation, two-wavelength quadrature demodulation and symmetric 3×3 coupler methodare discussed and compared in this paper.

  15. High-spin research with HERA (High Energy-Resolution Array)

    Energy Technology Data Exchange (ETDEWEB)

    Diamond, R.M.

    1987-06-01

    The topic of this report is high spin research with the High Energy Resolution Array (HERA) at Lawrence Berkeley Laboratory. This is a 21 Ge detector system, the first with bismuth germanate (BGO) Compton suppression. The array is described briefly and some of the results obtained during the past year using this detector facility are discussed. Two types of studies are described: observation of superdeformation in the light Nd isotopes, and rotational damping at high spin and excitation energy in the continuum gamma ray spectrum.

  16. Bimetallic gold-silver nanoplate array as a highly active SERS substrate for detection of streptavidin/biotin assemblies.

    Science.gov (United States)

    Bi, Liyan; Dong, Jian; Xie, Wei; Lu, Wenbo; Tong, Wei; Tao, Lin; Qian, Weiping

    2013-12-17

    The silver-modified gold nanoplate arrays as bimetallic surface-enhanced Raman scattering (SERS) substrates were optimized for the surface-enhanced Raman detection of streptavidin/biotin monolayer assemblies. The bimetallic gold-silver nanoplate arrays were fabricated by coating silver nanoparticles uniformly on the gold nanoplate arrays. Depending on silver nanoparticle coating, the localized surface plasmon resonance (LSPR) peak of the bimetallic gold-silver nanoplate arrays blue-shifted and broadened significantly. The common probe molecule, Niel Blue A sulfate (NBA) was used for testing the SERS activity of the bimetallic gold-silver nanoplate arrays. The SERS intensity increased with the silver nanoparticle coating, due to a large number of hot spots and nanoparticle interfaces. The platforms were tested against a monolayer of streptavidin functionalized over the bimetallic gold-silver nanoplate arrays showing that good quality spectra could be acquired with a short acquisition time. The supramolecular interaction between streptavidin (strep) and biotin showed subsequent modification of Raman spectra that implied a change of the secondary structure of the host biomolecule. And the detection concentration for biotin by this method was as low as 1.0 nM. The enhanced SERS performance of such bimetallic gold-silver nanoplate arrays could spur further interest in the integration of highly sensitive biosensors for rapid, nondestructive, and quantitative bioanalysis, particularly in microfluidics.

  17. High sensitive radiation detector for radiology dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Valente, M.; Malano, F. [Instituto de Fisica Enrique Gaviola, Oficina 102 FaMAF - UNC, Av. Luis Medina Allende, Ciudad Universitaria, 5000 Cordoba (Argentina); Molina, W.; Vedelago, J., E-mail: valente@famac.unc.edu.ar [Laboratorio de Investigaciones e Instrumentacion en Fisica Aplicada a la Medicina e Imagenes por Rayos X, Laboratorio 448 FaMAF - UNC, Ciudad Universitaria, 5000 Cordoba (Argentina)

    2014-08-15

    Fricke solution has a wide range of applications as radiation detector and dosimetry. It is particularly appreciated in terms of relevant comparative advantages, like tissue equivalence when prepared in aqueous media like gel matrix, continuous mapping capability, dose rate recorded and incident direction independence as well as linear dose response. This work presents the development and characterization of a novel Fricke gel system, based on modified chemical compositions making possible its application in clinical radiology. Properties of standard Fricke gel dosimeter for high dose levels are used as starting point and suitable chemical modifications are introduced and carefully investigated in order to attain high resolution for low dose ranges, like those corresponding to radiology interventions. The developed Fricke gel radiation dosimeter system achieves the expected typical dose dependency, actually showing linear response in the dose range from 20 up to 4000 mGy. Systematic investigations including several chemical compositions are carried out in order to obtain a good enough dosimeter response for low dose levels. A suitable composition among those studied is selected as a good candidate for low dose level radiation dosimetry consisting on a modified Fricke solution fixed to a gel matrix containing benzoic acid along with sulfuric acid, ferrous sulfate, xylenol orange and ultra-pure reactive grade water. Dosimeter samples are prepared in standard vials for its in phantom irradiation and further characterization by spectrophotometry measuring visible light transmission and absorbance before and after irradiation. Samples are irradiated by typical kV X-ray tubes and calibrated Farmer type ionization chamber is used as reference to measure dose rates inside phantoms in at vials locations. Once sensitive material composition is already optimized, dose-response curves show significant improvement regarding overall sensitivity for low dose levels. According to

  18. High Efficient Universal Buck Boost Solar Array Regulator SAR Module

    Science.gov (United States)

    Kimmelmann, Stefan; Knorr, Wolfgang

    2014-08-01

    The high efficient universal Buck Boost Solar Array Regulator (SAR) module concept is applicable for a wide range of input and output voltages. The single point failure tolerant SAR module contains 3 power converters for the transfer of the SAR power to the battery dominated power bus. The converters are operating parallel in a 2 out of 3 redundancy and are driven by two different controllers. The output power of one module can be adjusted up to 1KW depending on the requirements. The maximum power point tracker (MPPT) is placed on a separate small printed circuit board and can be used if no external tracker signal is delivered. Depending on the mode and load conditions an efficiency of more than 97% is achievable. The stable control performance is achieved by implementing the magnetic current sense detection. The sensed power coil current is used in Buck and Boost control mode.

  19. High-resolution displacement sensor using squid array amplifier

    Science.gov (United States)

    Chui, T.; Penanen, K.; Barmatz, M.; Paik, H.

    Improvement in the measurement of displacement has profound implications for gravitational physics. Examples of high-impact projects that can benefit from a better displacement sensor are: detection of gravitational waves, test of the equivalence principle, search for the postulated ?axion? particle, and test of the inverse square law of gravity. We describe the concept of a new displacement sensor that makes use of a recent development in the Superconducting Quantum Interference Device (SQUID) technology. The SQUID array amplifier, invented by Welty and Martinis (IEEE Trans. Appl. Superconductivity 3, 2605, 1993), has about the same noise as a conventional SQUID; however, it can work at a much higher frequency of up to 5 MHz. We explain how the higher bandwidth can be translated into higher resolution using a bridge-balancing scheme that can simultaneously balance out both the carrier signal at the bridge output and the electrostatic force acting on the test mass.

  20. High-resolution imaging methods in array signal processing

    DEFF Research Database (Denmark)

    Xenaki, Angeliki

    The purpose of this study is to develop methods in array signal processing which achieve accurate signal reconstruction from limited observations resulting in high-resolution imaging. The focus is on underwater acoustic applications and sonar signal processing both in active (transmit and receive...... in active sonar signal processing for detection and imaging of submerged oil contamination in sea water from a deep-water oil leak. The submerged oil _eld is modeled as a uid medium exhibiting spatial perturbations in the acoustic parameters from their mean ambient values which cause weak scattering......) and passive (only receive) mode. The study addresses the limitations of existing methods and shows that, in many cases, the proposed methods overcome these limitations and outperform traditional methods for acoustic imaging. The project comprises two parts; The first part deals with computational methods...

  1. High sensitivity field asymmetric ion mobility spectrometer

    Science.gov (United States)

    Chavarria, Mario A.; Matheoud, Alessandro V.; Marmillod, Philippe; Liu, Youjiang; Kong, Deyi; Brugger, Jürgen; Boero, Giovanni

    2017-03-01

    A high sensitivity field asymmetric ion mobility spectrometer (FAIMS) was designed, fabricated, and tested. The main components of the system are a 10.6 eV UV photoionization source, an ion filter driven by a high voltage/high frequency n-MOS inverter circuit, and a low noise ion detector. The ion filter electronics are capable to generate square waveforms with peak-to-peak voltages up to 1000 V at frequencies up to 1 MHz with adjustable duty cycles. The ion detector current amplifier has a gain up to 1012 V/A with an effective equivalent input noise level down to about 1 fA/Hz1/2 during operation with the ion filter at the maximum voltage and frequency. The FAIMS system was characterized by detecting different standard chemical compounds. Additionally, we investigated the use of a synchronous modulation/demodulation technique to improve the signal-to-noise ratio in FAIMS measurements. In particular, we implemented the modulation of the compensation voltage with the synchronous demodulation of the ion current. The analysis of the measurements at low concentration levels led to an extrapolated limit of detection for acetone of 10 ppt with an averaging time of 1 s.

  2. A forward-backward fragment assembling algorithm for the identification of genomic amplification and deletion breakpoints using high-density single nucleotide polymorphism (SNP array

    Directory of Open Access Journals (Sweden)

    Bailey Dione K

    2007-05-01

    Full Text Available Abstract Background DNA copy number aberration (CNA is one of the key characteristics of cancer cells. Recent studies demonstrated the feasibility of utilizing high density single nucleotide polymorphism (SNP genotyping arrays to detect CNA. Compared with the two-color array-based comparative genomic hybridization (array-CGH, the SNP arrays offer much higher probe density and lower signal-to-noise ratio at the single SNP level. To accurately identify small segments of CNA from SNP array data, segmentation methods that are sensitive to CNA while resistant to noise are required. Results We have developed a highly sensitive algorithm for the edge detection of copy number data which is especially suitable for the SNP array-based copy number data. The method consists of an over-sensitive edge-detection step and a test-based forward-backward edge selection step. Conclusion Using simulations constructed from real experimental data, the method shows high sensitivity and specificity in detecting small copy number changes in focused regions. The method is implemented in an R package FASeg, which includes data processing and visualization utilities, as well as libraries for processing Affymetrix SNP array data.

  3. Experimental Results of the Sensitivity of a Low Noise Aperture Array Tile for the SKA

    CERN Document Server

    Woestenburg, E E M; Ivashina, M V

    2011-01-01

    Aperture arrays have been studied extensively for application in the next generation of large radio telescopes for astronomy, requiring extremely low noise performance. Prototype array systems need to demonstrate the low noise potential of aperture array technology. This paper presents noise measurements for an Aperture Array tile of 144 dual-polarized tapered slot antenna (TSA) elements, originally built and characterized for use as a Phased Array Feed for application in an L-band radio astronomical receiving system. The system noise budget is given and the dependency of the measured noise temperatures on the beam steering is discussed. A comparison is made of the measurement results with simulations of the noise behavior using a system noise model. This model includes the effect of receiver noise coupling, resulting from a changing active reflection coefficient and array noise contribution as a function of beam steering. Measurement results clearly demonstrate the validity of the model and thus the concept ...

  4. High speed, high power one-dimensional beam steering from a 6-element optical phased array.

    Science.gov (United States)

    Huang, W Ronny; Montoya, Juan; Kansky, Jan E; Redmond, Shawn M; Turner, George W; Sanchez-Rubio, Antonio

    2012-07-30

    Beam steering at high speed and high power is demonstrated from a 6-element optical phased array using coherent beam combining (CBC) techniques. The steering speed, defined as the inverse of the time to required to sweep the beam across the steering range, is 40 MHz and the total power is 396 mW. The measured central lobe FWHM width is 565 μrad. High on-axis intensity is maintained periodically by phase-locking the array via a stochastic-parallel-gradient-descent (SPGD) algorithm. A master-oscillator-power-amplifier (MOPA) configuration is used where the amplifier array elements are semiconductor slab-coupled-optical-waveguide-amplifiers (SCOWAs). The beam steering is achieved by LiNbO(3) phase modulators; the phase-locking occurs by current adjustment of the SCOWAs. The system can be readily scaled to GHz steering speed and multiwatt-class output.

  5. Monolayer graphene film on ZnO nanorod array for high-performance Schottky junction ultraviolet photodetectors.

    Science.gov (United States)

    Nie, Biao; Hu, Ji-Gang; Luo, Lin-Bao; Xie, Chao; Zeng, Long-Hui; Lv, Peng; Li, Fang-Ze; Jie, Jian-Sheng; Feng, Mei; Wu, Chun-Yan; Yu, Yong-Qiang; Yu, Shu-Hong

    2013-09-09

    A new Schottky junction ultraviolet photodetector (UVPD) is fabricated by coating a free-standing ZnO nanorod (ZnONR) array with a layer of transparent monolayer graphene (MLG) film. The single-crystalline [0001]-oriented ZnONR array has a length of about 8-11 μm, and a diameter of 100∼600 nm. Finite element method (FEM) simulation results show that this novel nanostructure array/MLG heterojunction can trap UV photons effectively within the ZnONRs. By studying the I-V characteristics in the temperature range of 80-300 K, the barrier heights of the MLG film/ZnONR array Schottky barrier are estimated at different temperatures. Interestingly, the heterojunction diode with typical rectifying characteristics exhibits a high sensitivity to UV light illumination and a quick response of millisecond rise time/fall times with excellent reproducibility, whereas it is weakly sensitive to visible light irradiation. It is also observed that this UV photodetector (PD) is capable of monitoring a fast switching light with a frequency as high as 2250 Hz. The generality of the above results suggest that this MLG film/ZnONR array Schottky junction UVPD will have potential application in future optoelectronic devices.

  6. Alternative Optimizations of X-ray TES Arrays: Soft X-rays, High Count Rates, and Mixed-Pixel Arrays

    Science.gov (United States)

    Kilbourne, C. A.; Bandler, S. R.; Brown, A.-D.; Chervenak, J. A.; Figueroa-Feliciano, E.; Finkbeiner, F. M.; Iyomoto, N.; Kelley, R. L.; Porter, F. S.; Smith, S. J.

    2007-01-01

    We are developing arrays of superconducting transition-edge sensors (TES) for imaging spectroscopy telescopes such as the XMS on Constellation-X. While our primary focus has been on arrays that meet the XMS requirements (of which, foremost, is an energy resolution of 2.5 eV at 6 keV and a bandpass from approx. 0.3 keV to 12 keV), we have also investigated other optimizations that might be used to extend the XMS capabilities. In one of these optimizations, improved resolution below 1 keV is achieved by reducing the heat capacity. Such pixels can be based on our XMS-style TES's with the separate absorbers omitted. These pixels can added to an array with broadband response either as a separate array or interspersed, depending on other factors that include telescope design and science requirements. In one version of this approach, we have designed and fabricated a composite array of low-energy and broad-band pixels to provide high spectral resolving power over a broader energy bandpass than could be obtained with a single TES design. The array consists of alternating pixels with and without overhanging absorbers. To explore optimizations for higher count rates, we are also optimizing the design and operating temperature of pixels that are coupled to a solid substrate. We will present the performance of these variations and discuss other optimizations that could be used to enhance the XMS or enable other astrophysics experiments.

  7. Three-dimensional electrodes for dye-sensitized solar cells: synthesis of indium-tin-oxide nanowire arrays and ITO/TiO2 core-shell nanowire arrays by electrophoretic deposition.

    Science.gov (United States)

    Wang, Hong-Wen; Ting, Chi-Feng; Hung, Miao-Ken; Chiou, Chwei-Huann; Liu, Ying-Ling; Liu, Zongwen; Ratinac, Kyle R; Ringer, Simon P

    2009-02-04

    Dye-sensitized solar cells (DSSCs) show promise as a cheaper alternative to silicon-based photovoltaics for specialized applications, provided conversion efficiency can be maximized and production costs minimized. This study demonstrates that arrays of nanowires can be formed by wet-chemical methods for use as three-dimensional (3D) electrodes in DSSCs, thereby improving photoelectric conversion efficiency. Two approaches were employed to create the arrays of ITO (indium-tin-oxide) nanowires or arrays of ITO/TiO(2) core-shell nanowires; both methods were based on electrophoretic deposition (EPD) within a polycarbonate template. The 3D electrodes for solar cells were constructed by using a doctor-blade for coating TiO(2) layers onto the ITO or ITO/TiO(2) nanowire arrays. A photoelectric conversion efficiency as high as 4.3% was achieved in the DSSCs made from ITO nanowires; this performance was better than that of ITO/TiO(2) core-shell nanowires or pristine TiO(2) films. Cyclic voltammetry confirmed that the reaction current was significantly enhanced when a 3D ITO-nanowire electrode was used. Better separation of charge carriers and improved charge transport, due to the enlarged interfacial area, are thought to be the major advantages of using 3D nanowire electrodes for the optimization of DSSCs.

  8. Front-end receiver electronics for high-frequency monolithic CMUT-on-CMOS imaging arrays.

    Science.gov (United States)

    Gurun, Gokce; Hasler, Paul; Degertekin, F

    2011-08-01

    This paper describes the design of CMOS receiver electronics for monolithic integration with capacitive micromachined ultrasonic transducer (CMUT) arrays for highfrequency intravascular ultrasound imaging. A custom 8-inch (20-cm) wafer is fabricated in a 0.35-μm two-poly, four-metal CMOS process and then CMUT arrays are built on top of the application specific integrated circuits (ASICs) on the wafer. We discuss advantages of the single-chip CMUT-on-CMOS approach in terms of receive sensitivity and SNR. Low-noise and high-gain design of a transimpedance amplifier (TIA) optimized for a forward-looking volumetric-imaging CMUT array element is discussed as a challenging design example. Amplifier gain, bandwidth, dynamic range, and power consumption trade-offs are discussed in detail. With minimized parasitics provided by the CMUT-on-CMOS approach, the optimized TIA design achieves a 90 fA/√Hz input-referred current noise, which is less than the thermal-mechanical noise of the CMUT element. We show successful system operation with a pulseecho measurement. Transducer-noise-dominated detection in immersion is also demonstrated through output noise spectrum measurement of the integrated system at different CMUT bias voltages. A noise figure of 1.8 dB is obtained in the designed CMUT bandwidth of 10 to 20 MHz.

  9. High-performance SPAD array detectors for parallel photon timing applications

    Science.gov (United States)

    Rech, I.; Cuccato, A.; Antonioli, S.; Cammi, C.; Gulinatti, A.; Ghioni, M.

    2012-02-01

    Over the past few years there has been a growing interest in monolithic arrays of single photon avalanche diodes (SPAD) for spatially resolved detection of faint ultrafast optical signals. SPADs implemented in planar technologies offer the typical advantages of microelectronic devices (small size, ruggedness, low voltage, low power, etc.). Furthermore, they have inherently higher photon detection efficiency than PMTs and are able to provide, beside sensitivities down to single-photons, very high acquisition speeds. In order to make SPAD array more and more competitive in time-resolved application it is necessary to face problems like electrical crosstalk between adjacent pixel, moreover all the singlephoton timing electronics with picosecond resolution has to be developed. In this paper we present a new instrument suitable for single-photon imaging applications and made up of 32 timeresolved parallel channels. The 32x1 pixel array that includes SPAD detectors represents the system core, and an embedded data elaboration unit performs on-board data processing for single-photon counting applications. Photontiming information is exported through a custom parallel cable that can be connected to an external multichannel TCSPC system.

  10. Experimental study on high-voltage solar array sustained arc discharge induced by high charging

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    It has been reported that sustained arc discharge induced by electrostatic discharge (ESD) could cause permanent damage to high-power and high-voltage solar array of spacecrafts. The paper focuses on ESD simulating experiments on Si and GaAs samples, and induces sustained arc discharge. The physical mechanism of sustained arc discharge is discussed by comparing the charging/discharging phenomena between Si and GaAs samples. The experiments show that sustained arc discharge can produce a permanent short-circuit channel between solar cell strings through which the solar array’s photovoltaic power may flow out sustainedly. The analyses show that sustained arc discharge strongly depends on solar array structure, solar array operating voltage, ESD characteristics and cell materials.

  11. High-Directivity Antenna Array Based on Artificial Electromagnetic Metamaterials with Low Refractive Index

    Directory of Open Access Journals (Sweden)

    Zhigang Xiao

    2015-01-01

    Full Text Available Planar metamaterials (MTMs with low refractive index are proposed as a cover in a high-gain patch antenna array configuration. This MTMs array antenna has the following features: the number of array elements significantly decreases compared with the conventional array; the elements spacing is larger than a wave length by far; the feeding network is simpler. MTMs are made of two layers of periodic square metallic grids and placed above the feeding array. With the same aperture size, the directivity of MTMs-cover antenna array is higher than the conventional antenna array. The simulation results show that an array of 2 × 2 patch elements integrated with MTMs yields about 26 dB of directivity which is higher than that of conventional 8 × 8 patch array. Furthermore, on the condition of the same aperture size, an array patch with 4 × 4 elements integrated with the MTMs-cover has an equivalent gain compared with the conventional patch array with 16 × 16 array elements. Obviously, the former has a simpler feeding network and higher aperture efficiency. The experimental work has verified that the 2 × 2 array case and the measured results have good agreement with the simulation.

  12. High-power laser arrays with 100% fill factor emission facet

    Science.gov (United States)

    Yanson, Dan A.; McDougall, Stewart D.; Qiu, Bocang; Loyo-Maldonado, Valentin; Bacchin, Gianluca; Robertson, Stephen; Bon, Sébastien; Marsh, John H.

    2008-02-01

    Novel types of laser diode array with a 100% filling factor at the emission facet are reported. The arrays utilize both parallel and tapered cavity emitters that are connected via a common Laterally Unconfined Non-Absorbing Mirror (LUNAM) defined with quantum-well intermixing technology at 808 nm wavelength. Two LUNAM array types are considered: incoherent (weakly coupled) and coherent (diffraction coupled). Incoherent LUNAM arrays benefit from a reduced power density at the facet, improving reliability, and a near-uniform intensity distribution across the array aperture. Stacked laser diode arrays built with LUNAM bars deliver 950 W power under QCW operation with monolithically integrated LUNAM Talbot cavity. The devices produce a single-lobed horizontal far-field pattern over a limited current range with <10% slope efficiency penalty compared to an uncoupled case. The LUNAM arrays are promising candidates for high-power, high-brightness and high-reliability operation.

  13. Polyoxometalate-modified TiO2 nanotube arrays photoanode materials for enhanced dye-sensitized solar cells

    Science.gov (United States)

    Liu, Ran; Sun, Zhixia; Zhang, Yuzhuo; Xu, Lin; Li, Na

    2017-10-01

    In this work, we prepared for the first time the TiO2 nanotube arrays (TNAs) photoanode with polyoxometalate(POMs)-modified TiO2 electron-transport layer for improving the performance of zinc phthalocyanine(ZnPc)-sensitized solar cells. The as-prepared POMs/TNAs/ZnPc composite photoanode exhibited higher photovoltaic performances than the TNAs/ZnPc photoanode, so that the power conversion efficiency of the solar cell device based on the POMs/TNAs/ZnPc photoanode displayed a notable improvement of 45%. These results indicated that the POMs play a key role in reducing charge recombination in phthalocyanine-sensitized solar cells, together with TiO2 nanotube arrays being helpful for electron transport. The mechanism of the performance improvement was demonstrated by the measurements of electrochemical impedance spectra and open-circuit voltage decay curves. Although the resulting performance is still below that of the state-of-the-art dye-sensitized solar cells, this study presents a new insight into improving the power conversion efficiency of phthalocyanine-sensitized solar cells via polyoxometalate-modified TiO2 nanotube arrays photoanode.

  14. Patterning the cone mosaic array in zebrafish retina requires specification of ultraviolet-sensitive cones.

    Directory of Open Access Journals (Sweden)

    Pamela A Raymond

    Full Text Available Cone photoreceptors in teleost fish are organized in precise, crystalline arrays in the epithelial plane of the retina. In zebrafish, four distinct morphological/spectral cone types occupy specific, invariant positions within a regular lattice. The cone lattice is aligned orthogonal and parallel to circumference of the retinal hemisphere: it emerges as cones generated in a germinal zone at the retinal periphery are incorporated as single-cell columns into the cone lattice. Genetic disruption of the transcription factor Tbx2b eliminates most of the cone subtype maximally sensitive to ultraviolet (UV wavelengths and also perturbs the long-range organization of the cone lattice. In the tbx2b mutant, the other three cone types (red, green, and blue cones are specified in the correct proportion, differentiate normally, and acquire normal, planar polarized adhesive interactions mediated by Crumbs 2a and Crumbs 2b. Quantitative image analysis of cell adjacency revealed that the cones in the tbx2b mutant primarily have two nearest neighbors and align in single-cell-wide column fragments that are separated by rod photoreceptors. Some UV cones differentiate at the dorsal retinal margin in the tbx2b mutant, although they are severely dysmorphic and are eventually eliminated. Incorporating loss of UV cones during formation of cone columns at the margin into our previously published mathematical model of zebrafish cone mosaic formation (which uses bidirectional interactions between planar cell polarity proteins and anisotropic mechanical stresses in the plane of the retinal epithelium to generate regular columns of cones parallel to the margin reproduces many features of the pattern disruptions seen in the tbx2b mutant.

  15. Study of performance of small gamma camera consisting of crystal pixel array and position sensitive photomultiplier tube

    Institute of Scientific and Technical Information of China (English)

    ZHU Jie; LIU Shi-Tao; LEI Xiao-Wen; YAN Tian-Xin; XU Zi-Zong; WANG Zhao-Min

    2005-01-01

    The performance of gamma camera with NaI(T1) array coupled with position sensitive photomultiplier tube (PSPMT) R2486 has been studied. The pixel size of NaI(T1) crystal is 2mm×2mm and the overall dimension of the array is 48.2mm×48.2mm×5mm. There are 484 pixels in a 22×22 matrix. Because each pixel can produce a much focused light spot and restrict the spread of photons, position resolution of the gamma camera is mainly determined by pixel size. It is shown that crystal array pixel can reduce shrinkage effect and improve intrinsic position resolution greatly via restricting the spread of photons. Experimental results demonstrate that its position resolution and linearity are much improved comparing with the gamma camera using planar crystals coupled with PSPMT.

  16. Highly sensitive direct conversion ultrasound interferometer

    Science.gov (United States)

    Svitelskiy, Oleksiy; Grossmann, John; Suslov, Alexey

    2015-03-01

    Being invented more than fifty years ago, the ultrasonic pulse-echo technique has proven itself as a valuable and indispensable non-destructive tool to explore elastic properties of materials in engineering and scientific tasks. We propose a new design for the instrument based on mass-produced integral microchips. In our design the radiofrequency echo-pulse signal is processed by AD8302 RF gain and phase detector (www.analog.com).Its phase output is linearly proportional to the phase difference between the exciting and response signals. The gain output is proportional to the log of the ratio of amplitudes of the received to the exciting signals. To exclude the non-linear fragments and to enable exploring large phase changes, we employ parallel connection of two detectors, fed by in-phase and quadrature signals respectively. The instrument allowed us exploring phase transitions with precision of ΔV / V ~10-7 (V is the ultrasound speed). The high sensitivity of the logarithmic amplifiers embedded into AD8302 requires good grounding and screening of the receiving circuitry.

  17. Core-shell diode array for high performance particle detectors and imaging sensors: status of the development

    Science.gov (United States)

    Jia, G.; Hübner, U.; Dellith, J.; Dellith, A.; Stolz, R.; Plentz, J.; Andrä, G.

    2017-02-01

    We propose a novel high performance radiation detector and imaging sensor by a ground-breaking core-shell diode array design. This novel core-shell diode array are expected to have superior performance respect to ultrahigh radiation hardness, high sensitivity, low power consumption, fast signal response and high spatial resolution simultaneously. These properties are highly desired in fundamental research such as high energy physics (HEP) at CERN, astronomy and future x-ray based protein crystallography at x-ray free electron laser (XFEL) etc.. This kind of detectors will provide solutions for these fundamental research fields currently limited by instrumentations. In this work, we report our progress on the development of core-shell diode array for the applications as high performance imaging sensors and particle detectors. We mainly present our results in the preparation of high aspect ratio regular silicon rods by metal assisted wet chemical etching technique. Nearly 200 μm deep and 2 μm width channels with high aspect ratio have been etched into silicon. This result will open many applications not only for the core-shell diode array, but also for a high density integration of 3D microelectronics devices.

  18. Fabrication of Highly-Oriented TiO2 Nanotube Arrays and Its Application in Dye-Sensitized Solar Cells%二氧化钛纳米管阵列制备及其在染料敏化太阳能电池中的应用

    Institute of Scientific and Technical Information of China (English)

    焦星剑; 林红; 李思钊; 李建保

    2011-01-01

    TiO2 nanotube arrays were fabricated by anodization of titanium foils in an ethylene glycol and NH-4F system. The dimensions of nanotubes were controlled by tailoring anodization voltage. Titania nanotube arrays with various lengths (10-45 μm) and pore sizes (50-150 nm) were prepared. The effect of anodization voltage on the microstructural morphology of nanotubes and performance of dye sensitized solar cells (DSCs) based on the TiO2 nanotube arrays was investigated. The experimental results show that the active surface area increases when the length of nanotubes is longer. The photocurrent and efficiency of DSCs enhanced with increasing anodization voltage, and a promising efficiency of 2.27% for DSCs based on anodized TiO2 nanotube arrays was achieved.%以NH4F的乙二醇溶液为电解液,采用阳极氧化法在钛板上制备二氧化钛纳米管阵列,通过调控氧化电压改变纳米管的长度和管径,得到了长度为10~45μm、管径为50~150nm的二氧化钛纳米管.分析了阳极氧化实验条件对TiO2纳米管尺寸的影响,并研究了TiO2纳米管阵列的尺寸对染料敏化太阳能电池(dye-sensitized solar cells,DSCs)性能的影响.结果表明;随着纳米管长度增加,表面积增大,电池的短路电流显著提高,光电转换效率也随之增大.基于TiO2纳米管阵列的DSCs最高光电转换效率达到了2.27%.

  19. High Sensitivity, High Frequency and High Time Resolution Decimetric Spectroscope

    Science.gov (United States)

    Sawant, H. S.; Rosa, R. R.

    1990-11-01

    RESUMEN. Se ha desarrollado el primer espectroscopio decimetrico latino americano operando en una banda de 100 MHz con alta resoluci6n de fre- cuencia (100 KHz) y tiempo (10 ms), alrededor de cualquier centro de frecuencia en el intervalo de 2000-200 MHz. El prop6sito de esta nota es describir investigaciones solares y no solares que se planean, progra ma de investigaci6n y la situaci6n actual de desarrollo de este espectroscopio. ABSTRACT. First Latin American Decimetric Spectroscope operating over a band of 100 MHz with high resolution in frequency (100 KHz) and time (10 ms), around any center frequency in the range of 2000-200 MHz is being developed. The purpose of this note is to describe planned solar, and non-solar, research programmes and present status of development of this spectroscope. Keq wo : INSTRUMENTS - SPECTROSCOPY

  20. High density penetrating electrode arrays for autonomic nerves.

    Science.gov (United States)

    Burns, John; Yee-Hsee Hsieh; Mueller, Andrew; Chevallier, Juliette; Sriram, T S; Lewis, Stephen J; Chew, Daniel; Achyuta, Anil; Fiering, Jason

    2016-08-01

    Electrode arrays for recording and stimulation in the central nervous system have enabled numerous advances in basic science and therapeutic strategies. In particular, micro-fabricated arrays with precision size and spacing offer the benefit of accessing single neurons and permit mapping of neuronal function. Similar advances are envisioned toward understanding the autonomic nervous system and developing therapies based on its modulation, but appropriate electrode arrays are lacking. Here, we present for the first time, a multi-channel electrode array suitable for penetration of peripheral nerves having diameters as small as 0.1mm, and demonstrate performance in vivo. These arrays have the potential to access multiple discrete nerve fibers in small nerves. We fabricated and characterized five-channel arrays and obtained preliminary recordings of activity when penetrating rat carotid sinus nerve. The electrodes were constructed using hybrid microfabrication processes. The individual electrode shafts are as small as 0.01mm in diameter and at its tip each has a defined site that is addressable via a standard electronic connector. In addition to acute in vivo results, we evaluate the device by electrochemical impedance spectroscopy. Having established the fabrication method, our next steps are to incorporate the arrays into an implantable configuration for chronic studies, and here we further describe concepts for such a device.

  1. CdS quantum dot-sensitized solar cells based on nano-branched TiO2 arrays

    Science.gov (United States)

    Liu, Chang; Li, Yitan; Wei, Lin; Wu, Cuncun; Chen, Yanxue; Mei, Liangmo; Jiao, Jun

    2014-03-01

    Nano-branched rutile TiO2 nanorod arrays were grown on F:SnO2 conductive glass (FTO) by a facile, two-step wet chemical synthesis process at low temperature. The length of the nanobranches was tailored by controlling the growth time, after which CdS quantum dots were deposited on the nano-branched TiO2 arrays using the successive ionic layer adsorption and reaction method to make a photoanode for quantum dot-sensitized solar cells (QDSCs). The photovoltaic properties of the CdS-sensitized nano-branched TiO2 solar cells were studied systematically. A short-circuit current intensity of approximately 7 mA/cm2 and a light-to-electricity conversion efficiency of 0.95% were recorded for cells based on optimized nano-branched TiO2 arrays, indicating an increase of 138% compared to those based on unbranched TiO2 nanorod arrays. The improved performance is attributed to a markedly enlarged surface area provided by the nanobranches and better electron conductivity in the one-dimensional, well-aligned TiO2 nanorod trunks.

  2. Light trapping considerations in self-assembled ZnO nanorod arrays for quantum dot sensitized solar cells

    Science.gov (United States)

    Luan, ChunYan; Cheung, King Tai; Foo, Yishu; Yu, Li Yu; Shen, Qing; Zapien, Juan Antonio

    2014-03-01

    We study light absorption in ZnO nanorod arrays sensitized with CdSe quantum dots as one of the factors affecting solar cell performance in need of improvement given their current performance well below expectations. Light trapping in nanorod arrays (NRAs) as it relates to array density and length as well as quantum dot (QD) loading is studied using the Finite Difference Time Domain model. It is shown that light absorption in such solar cell architecture is a sensitive function of the morphological dimensions and that a higher NRA density does not necessarily correspond to large absorption in the solar cell. Instead, light trapping efficiency depends significantly on the array density, QD axial distribution and refractive index contrast between NR and QDs thus suggesting strategies for improved quantum dot solar cell (QDSC) fabrication. In addition, we present experimental data showing dramatic improvement in photo conversion efficiency performance for relatively short ZnO NRAs (~1 μm) of low NRA density, but whose efficiency improvement can not be solely explained based on our current light trapping estimates from the numerical simulations.

  3. Fabrication of high thermal conductivity arrays of carbon nanotubes and their composites

    Science.gov (United States)

    Geohegan, David B [Knoxville, TN; Ivanov, Ilya N [Knoxville, TN; Puretzky, Alexander A [Knoxville, TN

    2010-07-27

    Methods and apparatus are described for fabrication of high thermal conductivity arrays of carbon nanotubes and their composites. A composition includes a vertically aligned nanotube array including a plurality of nanotubes characterized by a property across substantially all of the vertically aligned nanotube array. A method includes depositing a vertically aligned nanotube array that includes a plurality of nanotubes; and controlling a deposition rate of the vertically aligned nanotubes array as a function of an in situ monitored property of the plurality of nanotubes.

  4. Site-Selective Controlled Dealloying Process of Gold-Silver Nanowire Array: a Simple Approach towards Long-Term Stability and Sensitivity Improvement of SERS Substrate

    Science.gov (United States)

    Wiriyakun, Natta; Pankhlueab, Karuna; Boonrungsiman, Suwimon; Laocharoensuk, Rawiwan

    2016-12-01

    Limitations of achieving highly sensitive and stable surface-enhanced Raman scattering (SERS) substrate greatly concern the suitable method for fabrication of large-area plasmonic nanostructures. Herein we report a simple approach using template-based synthesis to create a highly ordered two-dimensional array of gold-silver alloy nanowires, followed by the controlled dealloying process. This particular step of mild acid etching (15%v/v nitric acid for 5 min) allowed the formation of Raman hot spots on the nanowire tips while maintaining the integrity of highly active alloy composition and rigid nanowire array structure. Full consideration of SERS substrate performance was accomplished using 4-mercaptobenzoic acid (4-MBA) as a probe molecule. Exceedingly higher SERS signal (150-fold) can be achieved with respect to typical gold film substrate. Moreover, an excellent stability of SERS substrate was also determined for over 3 months storage time. In contrast to the previous studies which stability improvement was accomplished at a cost of sensitivity reduction, the simultaneous improvement of sensitivity and stability makes the controlled dealloying process an excellent choice of SERS substrate fabrication. In addition, uniformity and reproducibility studies indicated satisfactory results with the acceptable values of relative standard deviation.

  5. Birefringent Microlens Array for Ultra High Resolution HMDs Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project will be used to analyze, design, model, and test a birefringent microlens array for use in a new type of...

  6. A Compact High Energy Camera for the Cherenkov Telescope Array

    CERN Document Server

    Daniel, M K; Berge, D; Buckley, J; Chadwick, P M; Cotter, G; Funk, S; Greenshaw, T; Hidaka, N; Hinton, J; Lapington, J; Markoff, S; Moore, P; Nolan, S; Ohm, S; Okumura, A; Ross, D; Sapozhnikov, L; Schmoll, J; Sutcliffe, P; Sykes, J; Tajima, H; Varner, G S; Vandenbroucke, J; Vink, J; Williams, D

    2013-01-01

    The Compact High Energy Camera (CHEC) is a camera-development project involving UK, US, Japanese and Dutch institutes for the dual-mirror Small-Sized Telescopes (SST-2M) of the Cherenkov Telescope Array (CTA). Two CHEC prototypes, based on different photosensors are funded and will be assembled and tested in the UK over the next ~18 months. CHEC is designed to record flashes of Cherenkov light lasting from a few to a hundred nanoseconds, with typical RMS image width and length of ~0.2 x 1.0 degrees, and has a 9 degree field of view. The physical camera geometry is dictated by the telescope optics: a curved focal surface with radius of curvature 1m and diameter ~35cm is required. CHEC is designed to work with both the ASTRI and GATE SST-2M telescope structures and will include an internal LED flasher system for calibration. The first CHEC prototype will be based on multi-anode photomultipliers (MAPMs) and the second on silicon photomultipliers (SiPMs or MPPCs). The first prototype will soon be installed on the...

  7. High NA diffractive array illuminators and application in a multi-spot scanning microscope

    NARCIS (Netherlands)

    Hulsken, B.; Vossen, D.; Stallinga, S.

    2012-01-01

    Array illuminators generating spots with high NA at high efficiency are presented. They are designed via application of high-NA scalar optics methods, and implemented as periodic binary phase structures. These array illuminators are used in a multi-spot scanning microscope for scanning large sample

  8. Array Tomography: High-Resolution Three-Dimensional Immunofluorescence

    OpenAIRE

    sprotocols

    2014-01-01

    Authors: Kristina D. Micheva, Nancy O’Rourke, Brad Busse and Stephen J. Smith Adapted from [*Imaging: A Laboratory Manual* ](http://www.cshlpress.com/link/imagingp.htm)(ed. Yuste). CSHL Press, Cold Spring Harbor, NY, USA, 2010. ### INTRODUCTION Array tomography, which is described in this article, is a volumetric microscopy method based on physical serial sectioning. Ultrathin sections of a plastic-embedded tissue are cut using an ultramicrotome, bonded in an ordered array to a g...

  9. Effect of the geometry of the anodized titania nanotube array on the performance of dye-sensitized solar cells.

    Science.gov (United States)

    Sun, Lidong; Zhang, Sam; Sun, Xiaowei; He, Xiaodong

    2010-07-01

    Highly ordered TiO2 nanotube arrays are superior photoanodes for dye-sensitized solar cells (DSSCs) due to reduced intertube connections, vectorial electron transport, suppressed electron recombination, and enhanced light scattering. Performance of the cells is greatly affected by tube geometry, such as wall thickness, length, inner diameter and intertube spacing. In this paper, effect of geometry on the photovoltaic characteristics of DSSCs is reviewed. The nanotube wall has to be thick enough for a space charge layer to form for faster electron transportation and reduced recombination. When the tube wall is too thin to support the space charge layer, electron transport in the nanotubes will be hindered and reduced to that similar in a typical nanoparticle photoanode, and recombination will easily take place. Length of the nanotubes also plays a role: longer tube length is desired because of more dye loading, however, tube length longer than the electron diffusion length results in low collecting efficiency, which in turn, results in low short-circuit current density and thus low overall conversion efficiency. The tube inner diameter (pore size) affects the conversion efficiency through effective surface area, i.e., larger pore size gives rise to smaller surface area for dye adsorption, which results in low short-circuit current density under the same light soaking. Another issue that may seriously affect the conversion efficiency is whether each of the tube stands alone (free from connecting to the neighboring tubes) to facilitate infiltration of dye and fully use the outer surface area.

  10. Organic and inorganic surface passivations of TiO2 nanotube arrays for dye-sensitized photoelectrodes

    Science.gov (United States)

    Park, Hun; Yang, Changduk; Choi, Won-Youl

    2012-10-01

    Surface passivation of photoelectrodes is widely used to improve the performance of dye-sensitized solar cells (DSCs). We use the organic and inorganic materials as a surface-passivating layer of photoelectrodes and introduce the effect of surface passivation on the power conversion efficiency of DSCs. TiO2 nanotube arrays are fabricated by anodic oxidation of Ti foil for photoelectrodes of DSCs. Surface passivating layers are conducted by immersing photoelectrode in various precursor solutions. MgO and WO3 are selected for inorganic passivation. PC61BM is used for organic passivation. In case of inorganic passivation, a basic material (MgO) which has a high isoelectric point (pI >7) shows higher power conversion efficiency of 2.63% by increasing of open circuit voltage (Voc) to 0.74 V than bare sample of 2.55%. But, an acidic material (WO3) shifts Voc to low potential resulting in a worse efficiency of DSCs. In case of organic passivation, PC61BM enhances photocurrents and decreases Voc value compared to bare sample. The power conversion efficiency of PC61BM-coated DSCs is overall improved due to enhanced photocurrents despite of Voc offset to low potential. Back-transfer electron blocking, dye adsorption, TiO2 conduction band shifting, and additional charge generation by surface passivation are discussed.

  11. Composite Semiconductor Quantum Dots CdSe/CdS Co-sensitized TiO2 Nanorod Array Solar Cells

    Institute of Scientific and Technical Information of China (English)

    WANG Jingyang; ZHANG Tianjin; WANG Qingqing; WANG Duofa; PAN Ruikun; XIA Hanming

    2012-01-01

    CdSe/CdS semiconductor quantum dots co-sensitized TiO2 nanorod array was fabricated on the transparent conductive fluorine-doped tin oxide (FTO) substrate using the hydrothermal and successive ionic layer adsorption and reaction (SILAR) process.The structural and morphological properties of the samples were characterized by X-ray diffraction (XRD),field-emission scanning electron microscopy (FESEM),and transmission electron microscopy (TEM).The results indicate that CdSe/CdS QDs are uniformly coated on the surface of the TiO2 nanorods.The shift of light absorption edge was monitored by taking UV-visible absorption spectra.Compared with the absorption spectra of the TiO2 nanorod array,deposition of CdSe/CdS QDs shifts the absorption edge to the higher wavelength.The enhanced light absorption in the visible-light region of CdSe/CdS/TiO2 nanorod array indicates that CdSe/CdS layers can act as co-sensitizers in quantum dots sensitized solar cells (QDSSCs).By optimizing the CdSe layer deposition cycles,a photocurrent of 5.78 mA/cm2,an open circuit photovoltage of 0.469 V and a conversion efficiency of 1.34 % were obtained under an illumination of 100 mw/cm2.

  12. Formation of anodic TiO2 nanotube arrays in NaOH added fluoride-ethylene glycol electrolyte for dye-sensitized solar cells

    Science.gov (United States)

    Nyein, Nyein; Tan, Wai Kian; Kawamura, Go; Matsuda, Atsunori; Lockman, Zainovia

    2017-07-01

    TiO2 nanotube (TNT) arrays were formed by anodizing titanium foil in fluoride-ethylene glycol (EG) electrolyte added to it either water (H2O) or sodium hydroxide (NaOH) as oxidant. In NaOH added fluoride-EG electrolyte, 10 µm long TNT arrays were formed compared to 5 μm long nanotubes in H2O added fluoride-EG electrolyte. When NaOH was added to EG, the electrolyte pH was 9. As the pH of the electrolyte was rather high, surface etching of the nanotubes was reduced resulting in tubes with longer length. Moreover, the addition of NaOH into fluoride-EG resulted in the crystallization of anatase in the as-made TNT arrays. Annealing obviously improved the crystallinity of the oxide. The TNT arrays were then used as a photoanode in a dye-sensitized solar cell (DSSC). A photoconversion efficiency of 2.4 % was recorded with photocurrent of 6.9 mA/cm2.

  13. Using a sensitivity study to facilitate the design of a multi-electrode array to measure six cardiac conductivity values.

    Science.gov (United States)

    Johnston, Barbara M

    2013-07-01

    When using the bidomain model to model the electrical activity of the heart, there are potentially six cardiac conductivity values involved: conductivity values in directions along and normal to the cardiac fibres with a sheet, as well as a conductivity value in the normal direction between the sheets, and these occur for both the extracellular and intracellular domains in the model. To date it has been common to assume that the two normal direction conductivity values are the same. However, recent work has demonstrated that six cardiac conductivity values, rather than four, are necessary for accurate modelling, which can then facilitate understanding of cardiovascular disease. To design a method to determine these conductivities, it is also necessary to design a suitable multi-electrode array, which can be used, in conjunction with an inversion technique, to retrieve conductivity values from measurements of potential made on the array. This work uses the results of a study, into the sensitivity of the measuring potentials to variability in the input conductivities, to facilitate the design of an array that could be used to retrieve six cardiac conductivity values, as well as fibre rotation angle. It is found that if an electrode in the array has a much lower value of potential than the other electrodes, then it tends to be much more sensitive to the input conductivities than the other electrodes. It also appears that inclusion of this type of electrode in the set of measuring electrodes is essential for accurately retrieving conductivity values. This technique is used to identify electrodes to be included in the array and using the final design it is demonstrated, using synthetic values of potential, that the six cardiac conductivity values, and the fibre rotation angle, can be retrieved very accurately.

  14. A sensitive method to detect the hepatitis B virus mutations by using solid phase PCR on oligonucleotide array

    Institute of Scientific and Technical Information of China (English)

    YAN QIN LU; JIN XIANG HAN; ZHONG LIN SHEN; CHUAN XI WANG

    2006-01-01

    A sensitive method based on solid phase PCR on oligonucleotide array was established to detect two point mutations 1896G-A and 1901G-A in hepatitis B virus (HBV) DNA, in which 6 probes including these two point mutations were immobilized on modified glass slides through 5' terminal linker,while the 3' terminal was made to be free. The mutated loci were designed to locate on the last nucleotides of 3' terminal respectively, and the positive control probes lacked the last nucleotide of 3' terminal in comparison with the probes used for detection. Probes fixed on oligonucleotide array were also the solid phase amplification primers. One pair of liquid primers was used to amplify the short template product from whole HBV DNA. Using target DNA as template, the solid primers were extended under the action of Taq DNA polymerase and incorporated with Cy-3dCTP as marker. During the thermal cycling reaction,probes served as solid phase amplification primers and amplification products bound to the oligonucleotide array, which could be visualized by incorporation with fluorescent dyes. After amplification, the oligonucleotide array was washed, performed with laser scanning, and then used for quantitative analysis to obtain the information for mutations. The hybridization results were compared with DNA sequencing. It was demonstrated that in case of sample A, the ratios of fluorescence intensities in wide type and in the muin these two loci. These results correlated to those obtained from DNA sequencing analysis in which the fluorescence intensity ratios in wide type and in the mutated types of 1996G-A and 1901D-A mutations in using solid phase PCR based on oligonucleotide array appears to be a sensitive and promising way to detect mutations with low-density.

  15. New high fill-factor triangular micro-lens array fabrication method using UV proximity printing

    CERN Document Server

    Lin, T -H; Chao, C -K

    2008-01-01

    A simple and effective method to fabricate a high fill-factor triangular microlens array using the proximity printing in lithography process is reported. The technology utilizes the UV proximity printing by controlling a printing gap between the mask and substrate. The designed approximate triangle microlens array pattern can be fabricated the high fill-factor triangular microlens array in photoresist. It is due to the UV light diffraction to deflect away from the aperture edges and produce a certain exposure in photoresist material outside the aperture edges. This method can precisely control the geometric profile of high fill factor triangular microlens array. The experimental results showed that the triangular micro-lens array in photoresist could be formed automatically when the printing gap ranged from 240 micrometers to 840 micrometers. The gapless triangular microlens array will be used to increases of luminance for backlight module of liquid crystal displays.

  16. High-performance self-powered UV photodetectors based on TiO2 nano-branched arrays

    Science.gov (United States)

    Xie, Yanru; Wei, Lin; Li, Qinghao; Chen, Yanxue; Yan, Shishen; Jiao, Jun; Liu, Guolei; Mei, Liangmo

    2014-02-01

    Nano-branched TiO2 arrays were fabricated on fluorine-doped tin oxide (FTO) glass by a facile two-step chemical synthesis process. Self-powered UV photodetectors based on photoelectrochemical cells (PECs) were assembled using these TiO2 nano-branched arrays as photoanodes. These visible-blind self-powered UV photodetectors exhibit high sensitivity and high-speed photoresponse. Compared with photodetectors based on bare TiO2 nanorod arrays, TiO2 nano-branched arrays show drastically improved photodetecting performance as photoanodes. The photosensitivity increases from 0.03 to 0.22 A W-1 when optimized nano-branched TiO2 arrays are used, corresponding to an incident photon-to-current conversion efficiency higher than 77%. The UV photodetectors also exhibit excellent spectral selectivity and fast response (0.05 s decay time). The improved performance is attributed to a markedly enlarged TiO2/electrolyte contact area and good electron conductivity in the one-dimensional, well-aligned TiO2 nanorod trunk.

  17. High-performance self-powered UV photodetectors based on TiO2 nano-branched arrays.

    Science.gov (United States)

    Xie, Yanru; Wei, Lin; Li, Qinghao; Chen, Yanxue; Yan, Shishen; Jiao, Jun; Liu, Guolei; Mei, Liangmo

    2014-02-21

    Nano-branched TiO2 arrays were fabricated on fluorine-doped tin oxide (FTO) glass by a facile two-step chemical synthesis process. Self-powered UV photodetectors based on photoelectrochemical cells (PECs) were assembled using these TiO2 nano-branched arrays as photoanodes. These visible-blind self-powered UV photodetectors exhibit high sensitivity and high-speed photoresponse. Compared with photodetectors based on bare TiO2 nanorod arrays, TiO2 nano-branched arrays show drastically improved photodetecting performance as photoanodes. The photosensitivity increases from 0.03 to 0.22 A W(-1) when optimized nano-branched TiO2 arrays are used, corresponding to an incident photon-to-current conversion efficiency higher than 77%. The UV photodetectors also exhibit excellent spectral selectivity and fast response (0.05 s decay time). The improved performance is attributed to a markedly enlarged TiO2/electrolyte contact area and good electron conductivity in the one-dimensional, well-aligned TiO2 nanorod trunk.

  18. Highly Ordered TiO2 Macropore Arrays as Transparent Photocatalysts

    OpenAIRE

    Yuan Dong; Junfeng Chao; Zhong Xie; Xin Xu; Zhuoran Wang; Di Chen

    2012-01-01

    Highly ordered transparent TiO2 macropore arrays were synthesized via a simple glass-clamping method at room temperature. The as-synthesized TiO2 macropore arrays show high transmittance in the visible light region and can be used as transparent photocatalysts for degradation of organic dyes.

  19. A Broadband and High Gain Tapered Slot Antenna for W-Band Imaging Array Applications

    Directory of Open Access Journals (Sweden)

    Dong Sik Woo

    2014-01-01

    Full Text Available A broadband and high gain tapered slot antenna (TSA by utilizing a broadband microstrip- (MS- to-coplanar stripline (CPS balun has been developed for millimeter-wave imaging systems and sensors. This antenna exhibits ultrawideband performance for frequency ranges from 70 to over 110 GHz with the high antenna gain, low sidelobe levels, and narrow beamwidth. The validity of this antenna as imaging arrays is also demonstrated by analyzing mutual couplings and 4-element linear array. This antenna can be applied to mm-wave phased array, imaging array for plasma diagnostics applications.

  20. Final report on LDRD project : single-photon-sensitive imaging detector arrays at 1600 nm.

    Energy Technology Data Exchange (ETDEWEB)

    Childs, Kenton David; Serkland, Darwin Keith; Geib, Kent Martin; Hawkins, Samuel D.; Carroll, Malcolm S.; Klem, John Frederick; Sheng, Josephine Juin-Jye; Patel, Rupal K.; Bolles, Desta; Bauer, Tom M.; Koudelka, Robert

    2006-11-01

    The key need that this project has addressed is a short-wave infrared light detector for ranging (LIDAR) imaging at temperatures greater than 100K, as desired by nonproliferation and work for other customers. Several novel device structures to improve avalanche photodiodes (APDs) were fabricated to achieve the desired APD performance. A primary challenge to achieving high sensitivity APDs at 1550 nm is that the small band-gap materials (e.g., InGaAs or Ge) necessary to detect low-energy photons exhibit higher dark counts and higher multiplication noise compared to materials like silicon. To overcome these historical problems APDs were designed and fabricated using separate absorption and multiplication (SAM) regions. The absorption regions used (InGaAs or Ge) to leverage these materials 1550 nm sensitivity. Geiger mode detection was chosen to circumvent gain noise issues in the III-V and Ge multiplication regions, while a novel Ge/Si device was built to examine the utility of transferring photoelectrons in a silicon multiplication region. Silicon is known to have very good analog and GM multiplication properties. The proposed devices represented a high-risk for high-reward approach. Therefore one primary goal of this work was to experimentally resolve uncertainty about the novel APD structures. This work specifically examined three different designs. An InGaAs/InAlAs Geiger mode (GM) structure was proposed for the superior multiplication properties of the InAlAs. The hypothesis to be tested in this structure was whether InAlAs really presented an advantage in GM. A Ge/Si SAM was proposed representing the best possible multiplication material (i.e., silicon), however, significant uncertainty existed about both the Ge material quality and the ability to transfer photoelectrons across the Ge/Si interface. Finally a third pure germanium GM structure was proposed because bulk germanium has been reported to have better dark count properties. However, significant

  1. Radiation-hard/high-speed array-based optical engine

    Science.gov (United States)

    Gan, K. K.; Buchholz, P.; Heidbrink, S.; Kagan, H. P.; Kass, R. D.; Moore, J.; Smith, D. S.; Vogt, M.; Ziolkowski, M.

    2016-12-01

    We have designed and fabricated a compact array-based optical engine for transmitting data at 10 Gb/s. The device consists of a 4-channel ASIC driving a VCSEL (Vertical Cavity Surface Emitting Laser) array in an optical package. The ASIC is designed using only core transistors in a 65 nm CMOS process to enhance the radiation-hardness. The ASIC contains an 8-bit DAC to control the bias and modulation currents of the individual channels in the VCSEL array. The DAC settings are stored in SEU (single event upset) tolerant registers. Several devices were irradiated with 24 GeV/c protons and the performance of the devices is satisfactory after the irradiation.

  2. Virtual electrodes for high-density electrode arrays

    Energy Technology Data Exchange (ETDEWEB)

    Cela, Carlos Jose; Lazzi, Gianluca

    2017-05-23

    The present embodiments are directed to implantable electrode arrays having virtual electrodes. The virtual electrodes may improve the resolution of the implantable electrode array without the burden of corresponding complexity of electronic circuitry and wiring. In a particular embodiment, a virtual electrode may include one or more passive elements to help steer current to a specific location between the active electrodes. For example, a passive element may be a metalized layer on a substrate that is adjacent to, but not directly connected to an active electrode. In certain embodiments, an active electrode may be directly coupled to a power source via a conductive connection. Beneficially, the passive elements may help to increase the overall resolution of the implantable array by providing additional stimulation points without requiring additional wiring or driver circuitry for the passive elements.

  3. Four parameters increase the sensitivity and specificity of the exon array analysis and disclose 25 novel aberrantly spliced exons in myotonic dystrophy.

    Science.gov (United States)

    Yamashita, Yoshihiro; Matsuura, Tohru; Shinmi, Jun; Amakusa, Yoshinobu; Masuda, Akio; Ito, Mikako; Kinoshita, Masanobu; Furuya, Hirokazu; Abe, Koji; Ibi, Tohru; Sahashi, Ko; Sahashi, Koo; Ohno, Kinji

    2012-06-01

    Myotonic dystrophy type 1 (DM1) is an RNA gain-of-function disorder in which abnormally expanded CTG repeats of DMPK sequestrate a splicing trans-factor MBNL1 and upregulate another splicing trans-factor CUGBP1. To identify a diverse array of aberrantly spliced genes, we performed the exon array analysis of DM1 muscles. We analyzed 72 exons by RT-PCR and found that 27 were aberrantly spliced, whereas 45 were not. Among these, 25 were novel and especially splicing aberrations of LDB3 exon 4 and TTN exon 45 were unique to DM1. Retrospective analysis revealed that four parameters efficiently detect aberrantly spliced exons: (i) the signal intensity is high; (ii) the ratio of probe sets with reliable signal intensities (that is, detection above background P-value=0.000) is high within a gene; (iii) the splice index (SI) is high; and (iv) SI is deviated from SIs of the other exons that can be estimated by calculating the deviation value (DV). Application of the four parameters gave rise to a sensitivity of 77.8% and a specificity of 95.6% in our data set. We propose that calculation of DV, which is unique to our analysis, is of particular importance in analyzing the exon array data.

  4. Water-cooled hard-soldered kilowatt laser diode arrays operating at high duty cycle

    Science.gov (United States)

    Klumel, Genady; Karni, Yoram; Oppenhaim, Jacob; Berk, Yuri; Shamay, Moshe; Tessler, Renana; Cohen, Shalom; Risemberg, Shlomo

    2010-04-01

    High brightness laser diode arrays are increasingly found in defense applications either as efficient optical pumps or as direct energy sources. In many instances, duty cycles of 10- 20 % are required, together with precise optical collimation. System requirements are not always compatible with the use of microchannel based cooling, notwithstanding their remarkable efficiency. Simpler but effective solutions, which will not involve high fluid pressure drops as well as deionized water, are needed. The designer is faced with a number of challenges: effective heat removal, minimization of the built- in and operational stresses as well as precise and accurate fast axis collimation. In this article, we report on a novel laser diode array which includes an integral tap water cooling system. Robustness is achieved by all around hard solder bonding of passivated 940nm laser bars. Far field mapping of the beam, after accurate fast axis collimation will be presented. It will be shown that the design of water cooling channels , proper selection of package materials, careful design of fatigue sensitive parts and active collimation technique allow for long life time and reliability, while not compromising the laser diode array efficiency, optical power density ,brightness and compactness. Main performance characteristics are 150W/bar peak optical power, 10% duty cycle and more than 50% wall plug efficiency with less than 1° fast axis divergence. Lifetime of 0.5 Gshots with less than 10% power degradation has been proved. Additionally, the devices have successfully survived harsh environmental conditions such as thermal cycling of the coolant temperature and mechanical shocks.

  5. Ordered crystalline TiO{sub 2} nanohexagon arrays for improving conversion efficiency of dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Javed, Hafiz Muhammad Asif [Electronic Materials Research Laboratory, International Center for Dielectric Research, Key Laboratory of the Ministry of Education, State Key Laboratory for Manufacturing Systems Engineering, Xi' an Jiaotong University, Xi' an, 710049 (China); Que, Wenxiu, E-mail: wxque@mail.xjtu.edu.cn [Electronic Materials Research Laboratory, International Center for Dielectric Research, Key Laboratory of the Ministry of Education, State Key Laboratory for Manufacturing Systems Engineering, Xi' an Jiaotong University, Xi' an, 710049 (China); Yin, Xingtian; Xing, Yonglei; Liu, Xiaobin; Asghar, Ali; Shao, Jinyou [Electronic Materials Research Laboratory, International Center for Dielectric Research, Key Laboratory of the Ministry of Education, State Key Laboratory for Manufacturing Systems Engineering, Xi' an Jiaotong University, Xi' an, 710049 (China); Kong, Ling Bing, E-mail: ELBKong@ntu.edu.sg [School of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, Singapore, 639798 (Singapore)

    2015-10-15

    Anatase TiO{sub 2} nanohexagon arrays were grown by using an anodization process of Ti foil in fluoride containing electrolytes. Photoanode based on the as-grown anatase TiO{sub 2} nanohexagon arrays for DSSCs showed a power photoconversion efficiency of 4.01% and incident photon-to-current conversion efficiency of 68%, which are significantly higher than those of the device based on anatase TiO{sub 2} nanotube arrays. This improvement in power conversion efficiency should be attributed to the fact that the nanotubes with hexagonal structure have higher surface area to allow the uploading of more dye molecules for light harvesting. Also, the spacing introduced inside the hexagon might allow the dye molecules to cover the interior of the walls. In addition, it is believed that the photoconversion efficiency can be further increased by optimizing the hexagonal structure through the electrochemical conditions. - Graphical abstract: Nanotubes with hexagonal structure have higher surface area to allow the uploading of more dye molecules for light harvesting in dye-sensitized solar cells. - Highlights: • A unique TiO{sub 2} nanohexagon arrays were grown by an anodization process. • Higher surface area for dye uploading provided by the hexagon structure. • TiO{sub 2} nanohexagon based photoanode has PCE of 4.01% and IPCE of 68%.

  6. Photonic Links for High-Performance Arraying of Antennas

    Science.gov (United States)

    Huang, Shouhua; Tjoelker, Robert

    2009-01-01

    An architecture for arraying microwave antennas in the next generation of NASA s Deep Space Network (DSN) involves the use of all photonic links between (1) the antennas in a given array and (2) a signal processing center. In this architecture, all affected parts at each antenna pedestal [except a front-end low-noise amplifier for the radio-frequency (RF) signal coming from the antenna and an optical transceiver to handle monitor and control (M/C) signals] would be passive optical parts

  7. Sensitivity of linear CCD array based film scanners used for film dosimetry.

    Science.gov (United States)

    Devic, Slobodan; Wang, Yi-Zhen; Tomic, Nada; Podgorsak, Ervin B

    2006-11-01

    Film dosimetry is commonly performed by using linear CCD array transmission optical densitometers. However, these devices suffer from a variation in response along the detector array. If not properly corrected for, this nonuniformity may lead to significant overestimations of the measured dose as one approaches regions close to the edges of the scanning region. In this note, we present measurements of the spatial response of an AGFA Arcus II document scanner used for radiochromic film dosimetry. Results and methods presented in this work can be generalized to other CCD based transmission scanners used for film dosimetry employing either radiochromic or radiographic films.

  8. High-performance and high-sensitivity applications of graphene transistors with self-assembled monolayers.

    Science.gov (United States)

    Yeh, Chao-Hui; Kumar, Vinod; Moyano, David Ricardo; Wen, Shao-Hsuan; Parashar, Vyom; Hsiao, She-Hsin; Srivastava, Anchal; Saxena, Preeti S; Huang, Kun-Ping; Chang, Chien-Chung; Chiu, Po-Wen

    2016-03-15

    Charge impurities and polar molecules on the surface of dielectric substrates has long been a critical obstacle to using graphene for its niche applications that involve graphene's high mobility and high sensitivity nature. Self-assembled monolayers (SAMs) have been found to effectively reduce the impact of long-range scatterings induced by the external charges. Yet, demonstrations of scalable device applications using the SAMs technique remains missing due to the difficulties in the device fabrication arising from the strong surface tension of the modified dielectric environment. Here, we use patterned SAM arrays to build graphene electronic devices with transport channels confined on the modified areas. For high-mobility applications, both rigid and flexible radio-frequency graphene field-effect transistors (G-FETs) were demonstrated, with extrinsic cutoff frequency and maximum oscillation frequency enhanced by a factor of ~2 on SiO2/Si substrates. For high sensitivity applications, G-FETs were functionalized by monoclonal antibodies specific to cancer biomarker chondroitin sulfate proteoglycan 4, enabling its detection at a concentration of 0.01 fM, five orders of magnitude lower than that detectable by a conventional colorimetric assay. These devices can be very useful in the early diagnosis and monitoring of a malignant disease.

  9. Microshell Arrays Enhanced Sensitivity in Detection of Specific Antibody for Reduced Graphene Oxide Optical Sensor

    Directory of Open Access Journals (Sweden)

    Wen-Shuai Jiang

    2017-01-01

    Full Text Available Protein-protein interactions play an important role in the investigation of biomolecules. In this paper, we reported on the use of a reduced graphene oxide microshell (RGOM-based optical biosensor for the determination of goat anti-rabbit IgG. The biosensor was prepared through a self-assembly of monolayers of monodisperse polystyrene microspheres, combined with a high-temperature reduction, in order to decorate the RGOM with rabbit IgG. The periodic microshells allowed a simpler functionalization and modification of RGOM with bioreceptor units, than reduced graphene oxide (RGO. With additional antibody-antigen binding, the RGOM-based biosensor achieved better real-time and label-free detection. The RGOM-based biosensor presented a more satisfactory response to goat anti-rabbit IgG than the RGO-based biosensor. This method is promising for immobilizing biomolecules on graphene surfaces and for the fabrication of biosensors with enhanced sensitivity.

  10. Microshell Arrays Enhanced Sensitivity in Detection of Specific Antibody for Reduced Graphene Oxide Optical Sensor

    Science.gov (United States)

    Jiang, Wen-Shuai; Xin, Wei; Chen, Shao-Nan; Li, Cun-Bo; Gao, Xiao-Guang; Pan, Lei-Ting; Liu, Zhi-Bo; Tian, Jian-Guo

    2017-01-01

    Protein-protein interactions play an important role in the investigation of biomolecules. In this paper, we reported on the use of a reduced graphene oxide microshell (RGOM)-based optical biosensor for the determination of goat anti-rabbit IgG. The biosensor was prepared through a self-assembly of monolayers of monodisperse polystyrene microspheres, combined with a high-temperature reduction, in order to decorate the RGOM with rabbit IgG. The periodic microshells allowed a simpler functionalization and modification of RGOM with bioreceptor units, than reduced graphene oxide (RGO). With additional antibody-antigen binding, the RGOM-based biosensor achieved better real-time and label-free detection. The RGOM-based biosensor presented a more satisfactory response to goat anti-rabbit IgG than the RGO-based biosensor. This method is promising for immobilizing biomolecules on graphene surfaces and for the fabrication of biosensors with enhanced sensitivity. PMID:28125011

  11. [A simple highly sensitive recording microspectrophotometer].

    Science.gov (United States)

    Govardovskiĭ, V I; Zueva, L V

    1988-04-01

    A design of the recording microspectrophotometer is described. The instrument possesses an absolutely flat base line and quantum-noise limited detection threshold. Two principal elements of the design are the "jumping" stage, and the logarithmic amplifier with the phase-sensitive detector which converts the photomultiplier output into the optical density signal. The performance of the instrument is illustrated by the recordings of visual pigment spectra in single photoreceptors.

  12. Characterization of an array of Love-wave gas sensors developed using electrospinning technique to deposit nanofibers as sensitive layers.

    Science.gov (United States)

    Matatagui, D; Fernández, M J; Fontecha, J; Sayago, I; Gràcia, I; Cané, C; Horrillo, M C; Santos, J P

    2014-03-01

    The electrospinning technique has allowed that very different materials are deposited as sensitive layers on Love-wave devices forming a low cost and successful sensor array. Their excellent sensitivity, good linearity and short response time are reported in this paper. Several materials have been used to produce the nanofibers: polymers as Polyvinyl alcohol (PVA), Polyvinylpyrrolidone (PVP) and Polystirene (PS); composites with polymers as PVA+SnCl4; combined polymers as PS+Poly(styrene-alt-maleic anhydride) (PS+PSMA) and metal oxides (SnO2). In order to test the array, well-known chemical warfare agent simulants (CWAs) have been chosen among the volatile organic compounds due to their importance in the security field. Very low concentrations of these compounds have been detected by the array, such as 0.2 ppm of DMMP, a simulant of sarin nerve gas, and 1 ppm of DPGME, a simulant of nitrogen mustard. Additionally, the CWA simulants used in the experiment have been discriminated and classified using pattern recognition techniques, such as principal component analysis and artificial neural networks.

  13. Conductively cooled high-power high-brightness bars and fiber-coupled arrays

    Science.gov (United States)

    Zhou, Hailong; Mondry, Mark; Fouksman, Michael; Weiss, Eli; Anikitchev, Serguei; Kennedy, Keith; Li, Jun; Zucker, Erik; Rudy, Paul; Kongas, Jukka; Haapamaa, Jouko; Lehkonen, Sami

    2005-03-01

    Solid-state-laser and fiber laser pumping, reprographics, medical and materials processing applications require high power, high-brightness bars and fiber-coupled arrays. Conductively cooled laser diode bars allow customers to simplify system design and reduce operational size, weight, and costs. We present results on next generation high brightness, high reliability bars and fiber-coupled arrays at 790-830 nm, 940 nm and 980 nm wavelengths. By using novel epitaxial structures, we have demonstrated highly reliable 808 nm, 30% fill-factor conductively cooled bars operating at 60W CW mode, corresponding to a linear power density (LPD) of 20 mW/&mum. At 25°C, the bars have shown greater than 50% wall-plug-efficiency (WPE) when operating at 60W. Our novel approach has also reduced the fast-axis divergence FWHM from 31° to less than 24°. These bars have a 50% brightness improvement compared to our standard products with this geometry. At 980nm, we have demonstrated greater than 100W CW from 20% fill-factor conductively cooled bars, corresponding to a LPD of 50 mW/μm. At 25°C, the WPE for 976nm bars consistently peaks above 65% and remains greater than 60% at 100W. We coupled the beam output from those high-brightness bars into fiber-array-packages ("FAPs"), and we also achieved high-brightness and high-efficiency FAPs. We demonstrated 60W from a 600μm core-diameter fiber-bundle with a high WPE of 55%, and a low numerical aperture of 0.115. The brightness of such FAPs is four times higher than our standard high-power 40W FAP products at Coherent. Ongoing life test data suggests an extrapolated lifetime greater than 10,000 hours at 80W CW operating-condition based on 30%FF conductively cooled bar geometry.

  14. High Resolution Processing with an Active Phased Array SAR

    NARCIS (Netherlands)

    Nijenboer, F.J.; Otten, M.P.G.

    1999-01-01

    The Dutch PHARUS system is a polarimetric active phased array SAR capable of performing advanced SAR modes. Advanced SAR modes that are being investigated are: spotlight SAR, sliding spotlight SAR, stepped frequency SAR and interferometric SAR. The flight experiments and automatic beam steering

  15. Cognitive MIMO Frequency Diverse Array Radar with High LPI Performance

    Directory of Open Access Journals (Sweden)

    Ling Huang

    2016-01-01

    Full Text Available Frequency diverse array (FDA has its unique advantage in realizing low probability of intercept (LPI technology for its dependent beam pattern. In this paper, we proposed a cognitive radar based on the frequency diverse array multiple-input multiple-output (MIMO. To implement LPI of FDA MIMO transmit signals, a scheme for array weighting design is proposed, which is to minimize the energy of the target location and maximize the energy of the receiver. This is based on the range dependent characteristics of the frequency diverse array transmit beam pattern. To realize the objective problem, the algorithm is proposed as follows: the second-order nonconvex optimization problem is converted into a convex problem and solved by the bisection method and convex optimization. To get the information of target, the FDA MIMO radar is proposed to estimate the target parameters. Simulation results show that the proposed approach is effective in decreasing the detection probability of radar with lossless detection performance of the receive signal.

  16. Dye-sensitized solar cells based on nanoparticle-decorated ZnO/SnO2 core/shell nanoneedle arrays

    Science.gov (United States)

    Zhou, Yang; Xia, Chao; Hu, Xiaoyan; Huang, Wei; Aref, A. A.; Wang, Bixiao; Liu, Zhengjing; Sun, Yongming; Zhou, Wei; Tang, Yiwen

    2014-02-01

    Novel ZnO/SnO2 core-shell nanoneedle arrays were developed with a two-step synthesis strategy. The strategy combines two processes: a hydrothermal synthesis of a ZnO nanoneedle array and a coating of a SnO2 layer on the surface of the ZnO nanoneedle. The addition of F- to the hydrothermal reaction solution played an important role in the formation of the ZnO nanoneedle array. The ZnO/SnO2 core-shell structure was successfully achieved after depositing a thin SnO2 layer on the ZnO nanoneedle by dip-coating. Dye-sensitized solar cells (DSSCs) based on ZnO/SnO2 core-shell nanoneedle arrays were assembled, and a high conversion efficiency (η) of around 4.71% was obtained at 0.9 suns. This can be attributed to the advantages of the core-shell structure. On the one hand, it affords a larger surface area for a more dye loading and light harvesting, which result in enhancing the photocurrent of the DSSC. On the other hand, the core/shell structure passivates nanoneedle surface defects for suppressing the recombination, which leads to the increase of the open-circuit voltage. Accordingly, the enhanced photocurrent and open-circuit voltage have led to a prominent increase in the photovoltaic efficiency of around 4.71%, which is much higher than that of an ordinary ZnO nanoneedle array-based DSSC.

  17. CdS/CdSe quantum dot shell decorated vertical ZnO nanowire arrays by spin-coating-based SILAR for photoelectrochemical cells and quantum-dot-sensitized solar cells.

    Science.gov (United States)

    Zhang, Ran; Luo, Qiu-Ping; Chen, Hong-Yan; Yu, Xiao-Yun; Kuang, Dai-Bin; Su, Cheng-Yong

    2012-04-23

    A CdS/CdSe composite shell is assembled onto the surface of ZnO nanowire arrays with a simple spin-coating-based successive ionic layer adsorption and reaction method. The as-prepared photoelectrode exhibit a high photocurrent density in photoelectrochemical cells and also generates good power conversion efficiency in quantum-dot-sensitized solar cells.

  18. Investigation of the Optical and Sensing Characteristics of Nanoparticle Arrays for High Temperature Applications

    Science.gov (United States)

    Dharmalingam, Gnanaprakash

    The monitoring of polluting gases such as CO and NOx emitted from gas turbines in power plants and aircraft is important in order to both reduce the effects of such gases on the environment as well as to optimize the performance of the respective power system. The need for emissions monitoring systems is further realized from increased regulatory requirements that are being instituted as a result of the environmental impact from increased air travel. Specifically, it is estimated that the contributions from aircraft emissions to total NOx emissions will increase from 4% to 17% between 2008 and 2020. Extensive fuel cost savings as well as a reduced environmental impact would therefore be realized if this increased air traffic utilized next generation jet turbines which used a emission/performance control sensing system. These future emissions monitoring systems must be sensitive and selective to the emission gases, reliable and stable under harsh environmental conditions where the operation temperatures are in excess of 500 °C within a highly reactive environment. Plasmonics based chemical sensors which use nanocomposites comprised of a combination of gold nano particles and Yttria Stabilized Zirconia (YSZ) has enabled the sensitive (PPM) and stable detection (100s of hrs) of H2, NO2 and CO at temperatures of 500 °C. The detection method involves measuring the change in the localized Surface Plasmon Resonance (LSPR) characteristics of the Au- YSZ nano composite and in particular, the plasmon peak position. Selectivity remains a challenging parameter to optimize and a layer by layer sputter deposition approach has been recently demonstrated to modify the resulting sensing properties through a change in the morphology of the deposited films. The material properties of the films have produced a unique sensing behavior in terms of a preferential response to H2 compared to CO. Although this is a very good benefit, it is expected that further enhancements would be

  19. MEASURING HIGH-PRECISION ASTROMETRY WITH THE INFRARED ARRAY CAMERA ON THE SPITZER SPACE TELESCOPE

    Energy Technology Data Exchange (ETDEWEB)

    Esplin, T. L.; Luhman, K. L., E-mail: taran.esplin@psu.edu [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States)

    2016-01-15

    The Infrared Array Camera (IRAC) on the Spitzer Space Telescope currently offers the greatest potential for high-precision astrometry of faint mid-IR sources across arcminute-scale fields, which would be especially valuable for measuring parallaxes of cold brown dwarfs in the solar neighborhood and proper motions of obscured members of nearby star-forming regions. To more fully realize IRAC's astrometric capabilities, we have sought to minimize the largest sources of uncertainty in astrometry with its 3.6 and 4.5 μm bands. By comparing different routines that estimate stellar positions, we have found that Point Response Function (PRF) fitting with the Spitzer Science Center's Astronomical Point Source Extractor produces both the smallest systematic errors from varying intra-pixel sensitivity and the greatest precision in measurements of positions. In addition, self-calibration has been used to derive new 7th and 8th order distortion corrections for the 3.6 and 4.5 μm arrays of IRAC, respectively. These corrections are suitable for data throughout the mission of Spitzer when a time-dependent scale factor is applied to the corrections. To illustrate the astrometric accuracy that can be achieved by combining PRF fitting with our new distortion corrections, we have applied them to archival data for a nearby star-forming region, arriving at total astrometric errors of ∼20 and 70 mas at signal to noise ratios of 100 and 10, respectively.

  20. Measuring High-Precision Astrometry with the Infrared Array Camera on the Spitzer Space Telescope

    CERN Document Server

    Esplin, T L

    2015-01-01

    The Infrared Array Camera (IRAC) on the Spitzer Space Telescope currently offers the greatest potential for high-precision astrometry of faint mid-IR sources across arcminute-scale fields, which would be especially valuable for measuring parallaxes of cold brown dwarfs in the solar neighborhood and proper motions of obscured members of nearby star-forming regions. To more fully realize IRAC's astrometric capabilities, we have sought to minimize the largest sources of uncertainty in astrometry with its 3.6 and 4.5 $\\mu$m bands. By comparing different routines that estimate stellar positions, we have found that Point Response Function (PRF) fitting with the Spitzer Science Center's Astronomical Point Source Extractor produces both the smallest systematic errors from varying intra-pixel sensitivity and the greatest precision in measurements of positions. In addition, self-calibration has been used to derive new 7$^{\\rm th}$ and 8$^{\\rm th}$ order distortion corrections for the 3.6 and 4.5 $\\mu$m arrays of IRAC, ...

  1. Optical investigations of high pressure glow discharges based on MSE arrays

    Energy Technology Data Exchange (ETDEWEB)

    Penache, C.; Hohn, O.; Schmidt-Boecking, H. [Frankfurt Univ. (Germany); Spielberger, L. [Deutsche Gesellschaft fuer Technische Zusammenarbeit GmbH (GTZ), Eschborn (Germany); Braeuning-Demian, A.; Penache, D. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)

    2001-07-01

    The micro-structure-electrode (MSE) arrays are providing a non-thermal high pressure plasma. These arrays consist of a matrix of holes perforated in a thin multilayer made out of two metallic foils separated by a dielectric. The holes diameter and the thickness of the insulator spacer need to be around 100 {mu}m to allow for the MSE operation at pressure ranging from 0.1 to 1 bar and above. In this work single direct current microdischarges and systems of parallel operated holes in argon at 0.2 bar have been optically investigated. The spatial distribution of the emitted light has been monitored by a digital camera connected to an optical microscope. The UV photon emission has been recorded by a position sensitive photon detector allowing for space and time resolved measurements. Its time resolution of about 1 nsec makes possible the investigation of fast processes, e.g. the constriction of the discharge. Due to its typical position resolution of 100 {mu}m, this detector needs to be used in combination with an optical system allowing for the magnification of the discharge area. The optical appearance show a stable, volume filling glow discharge, fact proved also by the typical current-voltage characteristic.

  2. Highly Integrated, Reconfigurable, Large-Area, Flexible Radar Antenna Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Highly-integrated, reconfigurable radar antenna arrays fabricated on flexible substrates offer high functionality in a portable package that can be rolled up and...

  3. Highly reproducible SERS arrays directly written by inkjet printing

    Science.gov (United States)

    Yang, Qiang; Deng, Mengmeng; Li, Huizeng; Li, Mingzhu; Zhang, Cong; Shen, Weizhi; Li, Yanan; Guo, Dan; Song, Yanlin

    2014-12-01

    SERS arrays with uniform gold nanoparticle distribution were fabricated by direct-writing with an inkjet printing method. Quantitative analysis based on Raman detection was achieved with a small standard statistical deviation of less than 4% for the reproducibility and less than 5% for the long-term stability for 12 weeks.SERS arrays with uniform gold nanoparticle distribution were fabricated by direct-writing with an inkjet printing method. Quantitative analysis based on Raman detection was achieved with a small standard statistical deviation of less than 4% for the reproducibility and less than 5% for the long-term stability for 12 weeks. Electronic supplementary information (ESI) available: Additional information on the experimental details, gold nanoparticle characterization, and theoretical calculation for the diameters of contact area of droplets on substrates with different contact angles. See DOI: 10.1039/c4nr04656k

  4. High-energy interactions in Kinetic Inductance Detectors arrays

    CERN Document Server

    D'Addabbo, A; Goupy, J; Benoit, A; Bourrion, O; Catalano, A; Macias-Perez, J F; Monfardini, A

    2015-01-01

    The impacts of Cosmic Rays on the detectors are a key problem for space-based missions. We are studying the effects of such interactions on arrays of Kinetic Inductance Detectors (KID), in order to adapt this technology for use on board of satellites. Before proposing a new technology such as the Kinetic Inductance Detectors for a space-based mission, the problem of the Cosmic Rays that hit the detectors during in-flight operation has to be studied in detail. We present here several tests carried out with KID exposed to radioactive sources, which we use to reproduce the physical interactions induced by primary Cosmic Rays, and we report the results obtained adopting different solutions in terms of substrate materials and array geometries. We conclude by outlining the main guidelines to follow for fabricating KID for space-based applications.

  5. Highly Directive Reflect Array Antenna Design for Wireless Power Transfer

    Science.gov (United States)

    2017-04-14

    Duttagupta, “A broadband reflect-array with combination of sub-wavelength phasing elements,” in Asia Pacific Microwave Conference ( IEEE - APMC) New Delhi...1] Bialkowski et al. IEEE Transactions on Antennas and Propagation, November 2008 [2] Rajagopalan et al., IEEE Antennas and Propagation Magazine...October 2012 [3] Yoon et al., IEEE Transactions on Antennas and Propagation, February 2015 [4] Yoon et al., Electronics Letters, April 2014 Funds

  6. Controllable preparation of TiO{sub 2} nanowire arrays on titanium mesh for flexible dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wenwu; Lu, Hui; Zhang, Mei; Guo, Min, E-mail: guomin@ustb.edu.cn

    2015-08-30

    Graphical abstract: TiO{sub 2} nanowire arrays with controlled morphology and density have been synthesized on Ti mesh substrates by hydrothermal approach for flexible dye-sensitized solar cells which showed well photovoltaic efficiency of 3.42%. - Highlights: • Flexible titanium mesh was first used for hydrothermal preparation of TiO{sub 2} NWAs. • The formation mechanism of the TiO{sub 2} nanostructures was discussed. • The density, average diameter, and morphology of TiO{sub 2} NWAs can be controlled. • The effects of the sensitization temperature and time on the properties were studied. - Abstract: TiO{sub 2} nanowire arrays (NWAs) with an average diameter of 80 nm have been successfully synthesized on titanium (Ti) mesh substrates via hydrothermal method. The effects of preparing conditions such as concentration of NaOH solution, reaction time, and hydrothermal temperature on the growth of TiO{sub 2} nanoarrays and its related photovoltaic properties were systematically investigated by scanning electron microscopy, X-ray diffraction, and photovoltaic properties test. The growth mechanism of the Ti mesh-supported TiO{sub 2} nanostructures was discussed in detail. Moreover, a parametric study was performed to determine the optimized temperature and time of the dye sensitized process for the flexible dye-sensitized solar cell (DSSC). It is demonstrated that hydrothermal parameters had obvious influence on the morphology and growth density of the as-prepared TiO{sub 2} nanoarrays. In addition, the performance of the flexible DSSC depended strongly on the sensitization temperature and time. By utilizing Ti mesh-supported TiO{sub 2} NWAs (with a length of about 14 μm) as a photoanode, the flexible DSSC with a short circuit current density of 10.49 mA cm{sup −2}, an open-circuit voltage of 0.69 V, and an overall power conversion efficiency of 3.42% was achieved.

  7. Fabrication of plasmonic AgBr/Ag nanoparticles-sensitized TiO2 nanotube arrays and their enhanced photo-conversion and photoelectrocatalytic properties

    Science.gov (United States)

    Wang, Qingyao; Qiao, Jianlei; Jin, Rencheng; Xu, Xiaohui; Gao, Shanmin

    2015-03-01

    Plasmonic photosensitizer AgBr/Ag nanospheres supported on TiO2 nanotube arrays (TiO2 NTs) are prepared by successive ionic layer adsorption and reaction (SILAR) technique followed by photoreduction methods. The structural and surface morphological properties of AgBr/Ag nanoparticles sensitized TiO2 NTs and their photoelectrochemical performance are investigated and discussed. A detailed formation mechanism of the TiO2 NTs/AgBr/Ag is proposed. The TiO2 NTs/AgBr/Ag exhibit excellent photocurrent and photoelectrocatalytic activities under visible light irradiation. Efficient utilization of solar energy to create electron-hole pairs is attributed to the significant visible light response and surface plasmon resonance of Ag nanoparticles. This finding indicates that the high photosensitivity of the TiO2 NTs-based surface plasmon resonance materials could be applied toward the development of new plasmonic visible-light-sensitive photovoltaic fuel cells and photocatalysts.

  8. Ultra-sensitive vibrational spectroscopy of protein monolayers with plasmonic nanoantenna arrays.

    Science.gov (United States)

    Adato, Ronen; Yanik, Ahmet A; Amsden, Jason J; Kaplan, David L; Omenetto, Fiorenzo G; Hong, Mi K; Erramilli, Shyamsunder; Altug, Hatice

    2009-11-17

    Infrared absorption spectroscopy enabling direct access to vibrational fingerprints of the molecular structure is a powerful method for functional studies of bio-molecules. Although the intrinsic absorption cross-sections of IR active modes of proteins are nearly 10 orders of magnitude larger than the corresponding Raman cross-sections, they are still small compared to that of fluorescence-label based methods. Here, we developed a new tool based on collective excitation of plasmonic nanoantenna arrays and demonstrated direct detection of vibrational signatures of single protein monolayers. We first tailored the geometry of individual nanoantennas to form resonant structures that match the molecular vibrational modes. The tailored nanoantennas are then arranged in such a way that their in-phase dipolar coupling leads to a collective excitation of the ensemble with strongly enhanced near fields. The combined collective and individual plasmonic responses of the antenna array play a critical role in attaining signal enhancement factors of 10(4)-10(5). We achieved measurement of the vibrational spectra of proteins at zeptomole levels for the entire array, corresponding to only 145 molecules per antenna. The near-field nature of the plasmonic enhancement of the absorption signals is demonstrated with progressive loading of the nanoantennas with varying protein film thicknesses. Finally, an advanced model based on nonequilibrium Green's function formalism is introduced, which explains the observed Fano-type absorption line-shapes and tuning of the absorption strengths with the antenna resonance.

  9. High-Sensitivity GaN Microchemical Sensors

    Science.gov (United States)

    Son, Kyung-ah; Yang, Baohua; Liao, Anna; Moon, Jeongsun; Prokopuk, Nicholas

    2009-01-01

    Systematic studies have been performed on the sensitivity of GaN HEMT (high electron mobility transistor) sensors using various gate electrode designs and operational parameters. The results here show that a higher sensitivity can be achieved with a larger W/L ratio (W = gate width, L = gate length) at a given D (D = source-drain distance), and multi-finger gate electrodes offer a higher sensitivity than a one-finger gate electrode. In terms of operating conditions, sensor sensitivity is strongly dependent on transconductance of the sensor. The highest sensitivity can be achieved at the gate voltage where the slope of the transconductance curve is the largest. This work provides critical information about how the gate electrode of a GaN HEMT, which has been identified as the most sensitive among GaN microsensors, needs to be designed, and what operation parameters should be used for high sensitivity detection.

  10. Future plan for observation of cosmic gamma rays in the 100 TeV energy region with the Tibet air shower array : simulation and sensitivity

    CERN Document Server

    Amenomori, M; Chen, D; Cui, S W; Danzengluobu,; Ding, L K; Ding, X H; Fan, C; Feng, C F; Feng, Zhaoyang; Feng, Z Y; Gao, X Y; Geng, Q X; Guo, H W; He, H H; He, M; Hibino, K; Hotta, N; Hu, Haibing; Hu, H B; Huang, J; Huang, Q; Jia, H Y; Kajino, F; Kasahara, K; Katayose, Y; Kato, C; Kawata, K; Labaciren,; Le, G M; Li, A F; Li, J Y; Lou, Y -Q; Lü, H; Lu, S L; Meng, X R; Mizutani, K; Mu, J; Munakata, K; Nagai, A; Nanjo, H; Nishizawa, M; Ohnishi, M; Ohta, I; Onuma, H; Ouchi, T; Ozawa, S; Ren, J R; Saitô, T; Saito, T Y; Sakata, M; Sako, T K; Shibata, M; Shiomi, A; Shirai, T; Sugimoto, H; Takita, M; Tan, Y H; Tateyama, N; Torii, S; Tsuchiya, H; Udo, S; Wang, B; Wang, H; Wang, X; Wang, Y; Wang, Y G; Wu, H R; Xue, L; Yamamoto, Y; Yan, C T; Yang, X C; Yasue, S; Ye, Z H; Yu, G C; Yuan, A F; Yuda, T; Zhang, H M; Zhang, J L; Zhang, N J; Zhang, X Y; Zhang, Y; Zhang, Yi; Zhaxisangzhu,; Zhou, X X

    2007-01-01

    The Tibet air shower array, which has an effective area of 37,000 square meters and is located at 4300 m in altitude, has been observing air showers induced by cosmic rays with energies above a few TeV. We have a plan to add a large muon detector array to it for the purpose of increasing its sensitivity to cosmic gamma rays in the 100 TeV energy region by discriminating them from cosmic-ray hadrons. We have deduced the attainable sensitivity of the muon detector array using our Monte Carlo simulation. We report here on the detailed procedure of our Monte Carlo simulation.

  11. Measuring extended red sensitivity in a 1.7μm-cutoff HgCdTe detector array

    Science.gov (United States)

    Terrien, Ryan C.; Monson, Andrew J.; Mahadevan, Suvrath; Bender, Chad; Halverson, Samuel P.; Ramsey, Larry

    2016-08-01

    Infrared detectors with cutoff wavelengths of 1.7 μm have much lower sensitivity to thermal background contamination than those with longer cutoff wavelengths. This low sensitivity offers the attractive possibility of reducing the need for fully cryogenic systems for YJH-band work, offering the potential for "warm-pupil" instrumentation that nonetheless reduces detected thermal background to the level of dark current. However, residual sensitivity beyond the cutoff wavelength is not well characterized, and may preclude the implementation of such warm-pupil instruments. We describe an experiment to evaluate the long-wavelength sensitivity tail of a 1.7 µm-cutoff HAWAII-2RG array using a thermal blocking filter. Our results suggest the possibility of measurable red sensitivity beyond 2 μm. Ongoing improvements will confirm and refine this measurement. The thermal blocking filter offers the prospect of warm-pupil NIR instrument operation, which is particularly valuable for cost-effective and efficient testing systems: it has facilitated NIR detector characterization and will enable crucial laboratory tests of laser frequency comb calibration systems and other NIR calibration sources.

  12. Hydrothermal synthesis of rutile–anatase TiO{sub 2} nanobranched arrays for efficient dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Soon Jin; Im, Hyo Been [Graduate School of Energy Science and Technology, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Nam, Jung Eun; Kang, Jin Kyu [Advanced Convergence Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 50-1, Sang-ri, Hyeonpung-myeon, Dalseong-gun, Daegu 711-873 (Korea, Republic of); Hwang, Taek Sung [Department of Chemical Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Yi, Kwang Bok, E-mail: cosy32@cnu.ac.kr [Department of Chemical Engineering Education, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764 (Korea, Republic of)

    2014-11-30

    Highlights: • The unique rutile–anatase TiO{sub 2} nanobranched arrays have been synthesized for DSSC application. • TiO{sub 2} nano-structure consists of anatase nanobranches covering of rutile nanorod surfaces. • The successful attachment of anatase TiO{sub 2} nanobranches to the nanorods is achieved by TiCl{sub 4} treatment. - Abstract: Rutile–anatase TiO{sub 2} nanobranched arrays were prepared in two sequential hydrothermal-synthesis steps. The morphologies and crystalline nanostructures of the samples were investigated by controlling growth time and the concentration of the titanium precursor. All samples were characterized by field-emission scanning electron microscopy and X-ray diffraction analysis. It was found that treating the surfaces of rutile TiO{sub 2} nanorods with aqueous TiCl{sub 4} solutions allows the anatase TiO{sub 2} nanobranches to grow perpendicular to the main rutile TiO{sub 2} nanorods attached to the FTO glass. Irregularly shaped, dense TiO{sub 2} structures formed in the absence of TiCl{sub 4} treatment. A light-to-electricity conversion efficiency of 3.45% was achieved using 2.3 μm tall TiO{sub 2} nanobranched arrays in a dye-sensitized solar cell. This value is significantly higher than that observed for pure rutile TiO{sub 2} nanorods.

  13. ZnO nanosheet arrays constructed on weaved titanium wire for CdS-sensitized solar cells

    Science.gov (United States)

    Wu, Cuncun; Wei, Lin; Li, Yitan; Liu, Chang; Jiao, Jun; Chen, Yanxue; Mei, Liangmo

    2014-03-01

    Ordered ZnO nanosheet arrays were grown on weaved titanium wires by a low-temperature hydrothermal method. CdS nanoparticles were deposited onto the ZnO nanosheet arrays using the successive ionic layer adsorption and reaction method to make a photoanode. Nanoparticle-sensitized solar cells were assembled using these CdS/ZnO nanostructured photoanodes, and their photovoltaic performance was studied systematically. The best light-to-electricity conversion efficiency was obtained to be 2.17% under 100 mW/cm2 illumination, and a remarkable short-circuit photocurrent density of approximately 20.1 mA/cm2 was recorded, which could attribute to the relatively direct pathways for transportation of electrons provided by ZnO nanosheet arrays as well as the direct contact between ZnO and weaved titanium wires. These results indicate that CdS/ZnO nanostructures on weaved titanium wires would open a novel possibility for applications of low-cost solar cells.

  14. Optical modeling-assisted characterization of dye-sensitized solar cells using TiO2 nanotube arrays as photoanodes

    Directory of Open Access Journals (Sweden)

    Jung-Ho Yun

    2014-06-01

    Full Text Available Photovoltaic characteristics of dye-sensitized solar cells (DSSCs using TiO2 nanotube (TNT arrays as photoanodes were investigated. The TNT arrays were 3.3, 11.5, and 20.6 μm long with the pore diameters of 50, 78.6, and 98.7 nm, respectively. The longest TNT array of 20.6 μm in length showed enhanced photovoltaic performances of 3.87% with significantly increased photocurrent density of 8.26 mA·cm−2. This improvement is attributed to the increased amount of the adsorbed dyes and the improved electron transport property with an increase in TNT length. The initial charge generation rate was improved from 4 × 1021 s−1·cm−3 to 7 × 1021 s−1·cm−3 in DSSCs based on optical modelling analysis. The modelling analysis of optical processes inside TNT-based DSSCs using generalized transfer matrix method (GTMM revealed that the amount of dye and TNT lengths were critical factors influencing the performance of DSSCs, which is consistent with the experimental results.

  15. Kinetics of electron recombination of dye-sensitized solar cells based on TiO2 nanorod arrays sensitized with different dyes.

    Science.gov (United States)

    Wang, Hongxia; Liu, Meinan; Zhang, Min; Wang, Peng; Miura, Hidetoshi; Cheng, Yan; Bell, John

    2011-10-14

    The performance and electron recombination kinetics of dye-sensitized solar cells based on TiO(2) films consisting of one-dimensional nanorod arrays (NR-DSSCs) which are sensitized with dyes N719, C218 and D205, respectively, have been studied. It has been found that the best efficiency is obtained with the dye C218 based NR-DSSCs, benefiting from a 40% higher short-circuit photocurrent density. However, the open circuit photovoltage of the N719 based cell is 40 mV higher than that of the organic dye C218 and D205 based devices. Investigation of the electron recombination kinetics of the NR-DSSCs has revealed that the effective electron lifetime, τ(n), of the different dye based NR-DSSCs shows the sequence of C218 > D205 > N719. The higher V(oc) with the N719 based NR-DSSC is originated from the more negative energy level of the conduction band of the TiO(2) film. In addition, in comparison to the DSSCs with the conventional nanocrystalline particles based TiO(2) films, the NR-DSSCs have shown over two orders of magnitude higher τ(n) when employing N719 as the sensitizer. Nevertheless, the τ(n) of the DSSCs with the C218 based nanorod arrays is only ten-fold higher than that of the nanoparticles based devices. The remarkable characteristic of the dye C218 in suppressing the electron recombination of DSSCs is discussed.

  16. Design and microfabrication of a high-aspect-ratio PDMS microbeam array for parallel nanonewton force measurement and protein printing

    Science.gov (United States)

    Sasoglu, F. M.; Bohl, A. J.; Layton, B. E.

    2007-03-01

    Cell and protein mechanics has applications ranging from cellular development to tissue engineering. Techniques such as magnetic tweezers, optic tweezers and atomic force microscopy have been used to measure cell deformation forces of the order of piconewtons to nanonewtons. In this study, an array of polymeric polydimethylsiloxane (PDMS) microbeams with diameters of 10-40 µm and lengths of 118 µm was fabricated from Sylgard® with curing agent concentrations ranging from 5% to 20%. The resulting spring constants were 100-300 nN µm-1. The elastic modulus of PDMS was determined experimentally at different curing agent concentrations and found to be 346 kPa to 704 kPa in a millimeter-scale array and ~1 MPa in a microbeam array. Additionally, the microbeam array was used to print laminin for the purpose of cell adhesion. Linear and nonlinear finite element analyses are presented and compared to the closed-from solution. The highly compliant, transparent, biocompatible PDMS may offer a method for more rapid throughput in cell and protein mechanics force measurement experiments with sensitivities necessary for highly compliant structures such as axons.

  17. Triggers for a high sensitivity charm experiment

    Energy Technology Data Exchange (ETDEWEB)

    Christian, D.C.

    1994-07-01

    Any future charm experiment clearly should implement an E{sub T} trigger and a {mu} trigger. In order to reach the 10{sup 8} reconstructed charm level for hadronic final states, a high quality vertex trigger will almost certainly also be necessary. The best hope for the development of an offline quality vertex trigger lies in further development of the ideas of data-driven processing pioneered by the Nevis/U. Mass. group.

  18. Two-layer ZnO nanowire arrays: Fabrication and its photovoltaic property sensitized by CdSe and CdS quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Jingzhi [School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore); State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Wang, Jianxiong; Sun, Xiaowei [School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore)

    2015-09-01

    Two-layer ZnO nanowire arrays have been synthesized by a low temperature hydrothermal method. The two-layer structure enables the absorption of CdSe and CdS quantum dots (QDs) on different nanostructured layers, respectively. Solar cell based on the QD sensitized ZnO nanowire arrays is fabricated. Because sequential light adsorption of different sensitizers happens in two different layers, the photoanode can reduce the interaction possibility among different QDs and extend the absorption range, and result in improved photovoltaic properties. - Highlights: • Two-layer ZnO nanowire array has been synthesized by a low temperature hydrothermal. • A two-layer quantum dot sensitized ZnO nanowire array solar cell has been fabricated. • The structure can reduce interaction possibility among different quantum dots. • The structure can extend the range of light absorption.

  19. The Cherenkov Telescope Array: A Very-High-Energy Complement to Future High-Energy Space Missions

    Science.gov (United States)

    Williams, David A.; CTA Collaboration

    2017-01-01

    The Cherenkov Telescope Array (CTA) will be a new observatory for the study of very-high-energy gamma-ray sources, designed to achieve an order of magnitude improvement in sensitivity in the 30 GeV to 100 TeV energy band compared to currently operating instruments: VERITAS, MAGIC, and H.E.S.S. CTA will probe known sources with unprecedented sensitivity, angular resolution, and spectral coverage, while also detecting hundreds of new sources. CTA will provide access to data in this energy band to members of the wider astronomical community for the first time. The CTA Consortium will also conduct a number of Key Science Projects, including a Galactic Plane survey and a survey of one quarter of the extragalactic sky, creating legacy data sets that will also be available to the public. This presentation will highlight synergies between CTA and future high-energy missions in space. CTA is supported by the organizations listed at http://www.cta-observatory.org

  20. Highly specific detection of thrombin using an aptamer-based suspension array and the interaction analysis via microscale thermophoresis.

    Science.gov (United States)

    Liu, Yanan; Liu, Nan; Ma, Xinhua; Li, Xiaoli; Ma, Jia; Li, Ya; Zhou, Zhijiang; Gao, Zhixian

    2015-04-21

    A novel aptamer-based suspension array detection platform was designed for the sensitive, specific and rapid detection of human α-thrombin as a model. Thrombin was first recognized by a 29-mer biotinylated thrombin-binding aptamer (TBA) in solution. Then 15-mer TBA modified magnetic beads (MBs) captured the former TBA-thrombin to form an aptamer-thrombin-aptamer sandwich complex. The median fluorescence intensity obtained via suspension array technology was positively correlated with the thrombin concentration. The interactions between TBAs and thrombin were analyzed using microscale thermophoresis (MST). The dissociation constants could be respectively achieved to be 44.2 ± 1.36 nM (TBA1-thrombin) and 15.5 ± 0.637 nM (TBA2-thrombin), which demonstrated the high affinities of TBA-thrombin and greatly coincided with previous reports. Interaction conditions such as temperature, reaction time, and coupling protocol were optimized. The dynamic quantitative working range of the aptamer-based suspension array was 18.37-554.31 nM, and the coefficients of determination R(2) were greater than 0.9975. The lowest detection limit of thrombin was 5.4 nM. This method was highly specific for thrombin without being affected by other analogs and interfering proteins. The recoveries of thrombin spiked in diluted human serum were in the range 82.6-114.2%. This innovative aptamer-based suspension array detection platform not only exhibits good sensitivity based on MBs facilitating highly efficient separation and amplification, but also suggests high specificity by the selective aptamer binding, thereby suggesting the expansive application prospects in research and clinical fields.

  1. The Sensitivity of HAWC to High-Mass Dark Matter Annihilations

    CERN Document Server

    Abeysekara, A U; Alvarez, C; Álvarez, J D; Arceo, R; Arteaga-Velázquez, J C; Solares, H A Ayala; Barber, A S; Baughman, B M; Bautista-Elivar, N; Gonzalez, J Becerra; Belmont, E; BenZvi, S Y; Berley, D; Rosales, M Bonilla; Braun, J; Caballero-Lopez, R A; Caballero-Mora, K S; Carramiñana, A; Castillo, M; Cotti, U; Cotzomi, J; de la Fuente, E; De León, C; DeYoung, T; Hernandez, R Diaz; Diaz-Cruz, L; D\\'\\iaz-Vélez, J C; Dingus, B L; DuVernois, M A; Ellsworth, R W; E., S F; Fiorino, D W; Fraija, N; Galindo, A; Garfias, F; González, M M; Goodman, J A; Grabski, V; Gussert, M; Hampel-Arias, Z; Harding, J P; Hui, C M; Hüntemeyer, P; Imran, A; Iriarte, A; Karn, P; Kieda, D; Kunde, G J; Lara, A; Lauer, R J; Lee, W H; Lennarz, D; Vargas, H León; Linares, E C; Linnemann, J T; Longo, M; Luna-Garcia, R; Marinelli, A; Martinez, H; Martinez, O; Mart\\'\\inez-Castro, J; Matthews, J A J; McEnery, J; Torres, E Mendoza; Miranda-Romagnoli, P; Moreno, E; Mostafá, M; Nellen, L; Newbold, M; Noriega-Papaqui, R; Oceguera-Becerra, T; Patricelli, B; Pelayo, R; Pérez-Pérez, E G; Pretz, J; Rivière, C; Rosa-González, D; Ryan, J; Salazar, H; Salesa, F; Sandoval, A; Schneider, M; Silich, S; Sinnis, G; Smith, A J; Woodle, K Sparks; Springer, R W; Taboada, I; Toale, P A; Tollefson, K; Torres, I; Ukwatta, T N; Villaseñor, L; Weisgarber, T; Westerhoff, S; Wisher, I G; Wood, J; Yodh, G B; Younk, P W; Zaborov, D; Zepeda, A; Zhou, H; Abazajian, K N

    2014-01-01

    The High Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view detector sensitive to gamma rays of 100 GeV to a few hundred TeV. Located in central Mexico at 19 degrees North latitude and 4100 m above sea level, HAWC will observe gamma rays and cosmic rays with an array of water Cherenkov detectors. The full HAWC array is scheduled to be operational in Summer 2014. In this paper, we study the HAWC sensitivity to the gamma-ray signatures of high-mass (multi-TeV) dark matter annihilation. The HAWC observatory will be sensitive to diverse searches for dark matter annihilation, including annihilation from extended dark matter sources, the diffuse gamma-ray emission from dark matter annihilation, and gamma-ray emission from non-luminous dark matter subhalos. Here we consider the HAWC sensitivity to a subset of these sources, including dwarf galaxies, the M31 galaxy, the Virgo cluster, and the Galactic center. We simulate the HAWC response to gamma rays from these sources in several well-motivated dar...

  2. Fabrication of TiO{sub 2} nanotube–nanocube array composite electrode for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Shih-Yu [Institute of Organic and Polymeric Materials, National Taipei University of Technology, Taipei 10608, Taiwan (China); Su, Chaochin, E-mail: f10913@ntut.edu.tw [Institute of Organic and Polymeric Materials, National Taipei University of Technology, Taipei 10608, Taiwan (China); Kathirvel, Sasipriya [Institute of Organic and Polymeric Materials, National Taipei University of Technology, Taipei 10608, Taiwan (China); Li, Chung-Yen [Department of Chemistry, National Central University, Chung-Li 32001, Taiwan (China); Li, Wen-Ren, E-mail: ch01@ncu.edu.tw [Department of Chemistry, National Central University, Chung-Li 32001, Taiwan (China)

    2013-02-01

    One dimensional TiO{sub 2} nanotube structure recently plays an important role in the application of dye sensitized solar cells (DSSCs) due to its faster electron transport. The fabrication of photoanode using the TiO{sub 2} nanotube structures mixed with the TiO{sub 2} nanoparticles was investigated to enhance the photovoltaic efficiency of DSSCs by increasing the surface area of electrode. In this work, self-organized and vertically-oriented TiO{sub 2} nanotube arrays (TNAs) covered with uniformly distributed TiO{sub 2} nanocubes (TNCs) were fabricated in a simple one-step anodization process. The X-ray diffraction patterns reveal that both TNAs and TNCs are in anatase phase. The scanning electron microscopy analysis demonstrates that the wall thickness and inner diameter of hexagonal close-packed TiO{sub 2} nanotubes from chemically polished Ti foils are 10–15 and 100–120 nm, respectively, and the particle size of TNCs is 60–75 nm. The DSSC fabricated by the mixed morphological TNAs with TNCs shows an enhanced photoconversion efficiency of ∼ 63% than that of TNAs alone, due to the increase of both dye adsorption and electron transportation rate. - Highlights: ► Fabrication of TiO{sub 2} nanotube arrays on Ti foils was performed using anodization process. ► Nitrogen blow influences the growth of TiO2 nanocube particles on the TiO{sub 2} nanotube arrays. ► Mixed morphological nanotube–nanocube TiO{sub 2} photoanode in dye-sensitized solar cell achieved improved efficiency of 1.98%.

  3. Highly sensitive and selective sugar detection by terahertz nano-antennas

    CERN Document Server

    Lee, Dong-Kyu; Lee, Jun-Seok; Kim, Hyo-Seok; Kim, Chulki; Kim, Jae Hun; Lee, Taikjin; Son, Joo-Hiuk; Park, Q-Han; Seo, Minah

    2015-01-01

    Molecular recognition and discrimination of carbohydrates are important because carbohydrates perform essential roles in most living organisms for energy metabolism and cell-to-cell communication. Nevertheless, it is difficult to identify or distinguish various carbohydrate molecules owing to the lack of a significant distinction in the physical or chemical characteristics. Although there has been considerable effort to develop a sensing platform for individual carbohydrates selectively using chemical receptors or an ensemble array, their detection and discrimination limits have been as high in the millimolar concentration range. Here we show a highly sensitive and selective detection method for the discrimination of carbohydrate molecules using nano-slot-antenna array-based sensing chips which operate in the terahertz frequency range. This THz metamaterial sensing tool recognizes various types of carbohydrate molecules over a wide range of molecular concentrations. Strongly localized and enhanced terahertz t...

  4. Scalloped electrodes for highly sensitive electrical measurements

    DEFF Research Database (Denmark)

    Vazquez Rodriguez, Patricia; Dimaki, Maria; Svendsen, Winnie Edith

    2011-01-01

    In this work we introduce a novel out-of-plane electrode with pronounced scalloped surface and high aspect ratio for electrical recordings of brain tissue in vitro, with the aim to reduce significantly the impedance of the measuring system. The profile and height of the structures is tailored...... by means of silicon fabrication techniques that sharpen them progressively and in a controlled manner. We will show that the use of the scalloped area achieves a great decrease in impedance, which is very significant for a reduction of noise in electrical measurements. The measured impedance reflects...

  5. A nanofiber based artificial electronic skin with high pressure sensitivity and 3D conformability.

    Science.gov (United States)

    Zhong, Weibin; Liu, Qiongzhen; Wu, Yongzhi; Wang, Yuedan; Qing, Xing; Li, Mufang; Liu, Ke; Wang, Wenwen; Wang, Dong

    2016-06-16

    Pressure sensors with 3D conformability are highly desirable components for artificial electronic skin or e-textiles that can mimic natural skin, especially for application in real-time monitoring of human physiological signals. Here, a nanofiber based electronic skin with ultra-high pressure sensitivity and 3D conformability is designed and built by interlocking two elastic patterned nanofibrous membranes. The patterned membrane is facilely prepared by casting conductive nanofiber ink into a silicon mould to form an array of semi-spheroid-like protuberances. The protuberances composed of intertwined elastic POE nanofibers and PPy@PVA-co-PE nanofibers afford a tunable effective elastic modulus that is capable of capturing varied strains and stresses, thereby contributing to a high sensitivity for pressure sensing. This electronic skin-like sensor demonstrates an ultra-high sensitivity (1.24 kPa(-1)) below 150 Pa with a detection limit as low as about 1.3 Pa. The pixelated sensor array and a RGB-LED light are then assembled into a circuit and show a feasibility for visual detection of spatial pressure. Furthermore, a nanofiber based proof-of-concept wireless pressure sensor with a bluetooth module as a signal transmitter is proposed and has demonstrated great promise for wireless monitoring of human physiological signals, indicating a potential for large scale wearable electronic devices or e-skin.

  6. Arc arrays: studies of high resolution techniques for multibeam bathymetric applications

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, B.; Schenke, H.W.

    arrayof 15 degrees arc. The superiorityof the high resolution methods is seen by examining the patterns of the 15 degrees arc array under multiple source/interference conditions, i.e. the situation for rough terrain or artefactcreating conditions...

  7. TRUSSELATOR - On-Orbit Fabrication of High Performance Support Structures for Solar Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Trusselator technology will enable on-orbit fabrication of support structures for high-power solar arrays and large antennas, achieving order-of-magnitude...

  8. FDM-HAWK, A High Performance Compact Modular Solar Array Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Developing a next generation high performance solar array with significant reduction in size and weight will result in improved NASA mission capabilities at lower...

  9. High Resolution, Radiation Tolerant Focal Plane Array for Lunar And Deep Space Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Aerius Photonics and its partners propose the development of a high resolution, radiation hardened 3-D FLASH Focal Plane Array (FPA), with performance expected to be...

  10. Spiral-path high-sensitivity silicon photonic wire molecular sensor with temperature-independent response.

    Science.gov (United States)

    Densmore, A; Xu, D-X; Janz, S; Waldron, P; Mischki, T; Lopinski, G; Delâge, A; Lapointe, J; Cheben, P; Lamontagne, B; Schmid, J H

    2008-03-15

    We demonstrate a new silicon photonic wire waveguide evanescent field (PWEF) sensor that exploits the strong evanescent field of the transverse magnetic mode of this high-index-contrast, submicrometer-dimension waveguide. High sensitivity is achieved by using a 2 mm long double-spiral waveguide structure that fits within a compact circular area of 150 microm diameter, facilitating compatibility with commercial spotting apparatus and the fabrication of densely spaced sensor arrays. By incorporating the PWEF sensor element into a balanced waveguide Mach-Zehnder interferometer circuit, a minimum detectable mass of approximately 10 fg of streptavidin protein is demonstrated with near temperature-independent response.

  11. Monolithic blue LED series arrays for high-voltage AC operation

    Energy Technology Data Exchange (ETDEWEB)

    Ao, Jin-Ping [Satellite Venture Business Laboratory, University of Tokushima, Tokushima 770-8506 (Japan); Sato, Hisao; Mizobuchi, Takashi; Morioka, Kenji; Kawano, Shunsuke; Muramoto, Yoshihiko; Sato, Daisuke; Sakai, Shiro [Nitride Semiconductor Co. Ltd., Naruto, Tokushima 771-0360 (Japan); Lee, Young-Bae; Ohno, Yasuo [Department of Electrical and Electronic Engineering, University of Tokushima, Tokushima 770-8506 (Japan)

    2002-12-16

    Design and fabrication of monolithic blue LED series arrays that can be operated under high ac voltage are described. Several LEDs, such as 3, 7, and 20, are connected in series and in parallel to meet ac operation. The chip size of a single device is 150 {mu}m x 120 {mu}m and the total size is 1.1 mm x 1 mm for a 40(20+20) LED array. Deep dry etching was performed as device isolation. Two-layer interconnection and air bridge are utilized to connect the devices in an array. The monolithic series array exhibit the expected operation function under dc and ac bias. The output power and forward voltage are almost proportional to LED numbers connected in series. On-wafer measurement shows that the output power is 40 mW for 40(20+20) LED array under ac 72 V. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

  12. High Precision and High Yield Fabrication of Dense Nanoparticle Arrays onto DNA Origami at Statistically Independent Binding Sites †

    OpenAIRE

    Takabayashi, Sadao; Klein, William P.; Onodera, Craig; Rapp, Blake; Flores-Estrada, Juan; Lindau, Elias; Snowball, Lejmarc; Sam, Joseph Tyler; Padilla, Jennifer E.; Lee, Jeunghoon; Knowlton, William B.; Graugnard, Elton; Yurke, Bernard; Kuang, Wan; Hughes, William L.

    2014-01-01

    High precision, high yield, and high density self-assembly of nanoparticles into arrays is essential for nanophotonics. Spatial deviations as small as a few nanometers can alter the properties of near-field coupled optical nanostructures. Several studies have reported assemblies of few nanoparticle structures with controlled spacing using DNA nanostructures with variable yield. Here, we report multi-tether design strategies and attachment yields for homo- and hetero-nanoparticle arrays templa...

  13. Patterned growth of high aspect ratio silicon wire arrays at moderate temperature

    Science.gov (United States)

    Morin, Christine; Kohen, David; Tileli, Vasiliki; Faucherand, Pascal; Levis, Michel; Brioude, Arnaud; Salem, Bassem; Baron, Thierry; Perraud, Simon

    2011-04-01

    High aspect ratio silicon wire arrays with excellent pattern fidelity over wafer-scale area were grown by chemical vapor deposition at moderate temperature, using a gas mixture of silane and hydrogen chloride. An innovative two-step process was developed for in situ doping of silicon wires by diborane. This process led to high p-type doping levels, up to 10 18-10 19 cm -3, without degradation of the silicon wire array pattern fidelity.

  14. Multipurpose High Sensitivity Radiation Detector: Terradex

    Energy Technology Data Exchange (ETDEWEB)

    Alpat, Behcet [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy)]. E-mail: behcet.alpat@pg.infn.it; Aisa, Damiano [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Bizzarri, Marco [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Blasko, Sandor [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Esposito, Gennaro [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Farnesini, Lucio [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Fiori, Emmanuel [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Papi, Andrea [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Postolache, Vasile [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Renzi, Francesca [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Ionica, Romeo [Politecnica University of Bucarest, Splaiul Indipendentei, Bucharest (Romania); Manolescu, Florentina [Space Science Institute of Bucharest, Maugurele, Bucharest (Romania); Ozkorucuklu, Suat [Suleyman Demirel Universitesi, Isparta (Turkey); Denizli, Haluk [Abant Izzet Baysal Universitesi, Bolu (Turkey); Tapan, Ilhan [Uludag Universitesi, Bursa (Turkey); Ercan Pilicer [Uludag Universitesi, Bursa (Turkey); Egidi, Felice [SITE Technology, Carsoli (Italy); Moretti, Cesare [SITE Technology, Carsoli(AQ) (Italy); Dicola, Luca [SITE Technology, Carsoli(AQ) (Italy)

    2007-05-11

    Terradex project aims to realise an accurate and programmable multiparametric tool which will measure relevant physical quantities such as observation time, energy and type of all decay products of three naturally occurring decay chains of uranium and thorium series present in nature as well as the decay products of man-made radioactivity. The measurements described in this work are based on the performance tests of the first version of an instrument that is designed to provide high counting accuracy, by introducing self-triggering, delayed time-coincidence technique, of products of a given decay chain. In order to qualify the technique and to calibrate the Terradex, a {sup 222}Rn source is used. The continuous and accurate monitoring of radon concentration in air is realised by observing the alpha and beta particles produced by the decay of {sup 222}Rn and its daughters and tag each of them with a precise occurrence time. The validity of delayed coincident technique by using the state of the art electronics with application of novel data sampling and analysis methods are discussed. The flexibility of sampling protocols and the advantages of online calibration capability to achieve the highest level of precision in natural and man-made radiation measurements are also described.

  15. Unlikely Combination of Experiments With a Novel High-Voltage CIGS Photovoltaic Array: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    del Cueto, J. A.; Sekulic, B. R.

    2006-05-01

    A new high-voltage array comprising bipolar strings of copper indium gallium diselenide (CIGS) photovoltaic (PV) modules was inaugurated in 2005. It is equipped with a unique combination of tests, which likely have never before been deployed simultaneously within a single array: full current-voltage (I-V) traces, high-voltage leakage current measurements, and peak-power tracking or temporal stepped-bias profiling. The array nominally produces 1 kW power at 1 sun. The array's electrical characteristics are continuously monitored and controlled with a programmable electronic load interfaced to a data acquisition system (DAS), that also records solar and meteorological data. The modules are mounted with their frames electrically isolated from earth ground, in order to facilitate measurement of the leakage currents that arise between the high voltage bias developed in the series-connected cells and modules and their mounting frames. Because the DAS can perform stepped biasing of the array as a function of time, synchronous detection of the leakage current data with alternating bias is available. Leakage current data and their dependence on temperature and voltage are investigated. Array power data are analyzed across a wide range of varying illuminations and temperatures from the I-V traces. Array performance is also analyzed from an energy output perspective using peak-power tracking data.

  16. Electronic system for high power load control. [solar arrays

    Science.gov (United States)

    Miller, E. L. (Inventor)

    1980-01-01

    Parallel current paths are divided into two groups, with control devices in the current paths of one group each having a current limiting resistor, and the control devices in the other group each having no limiting resistor, so that when the control devices of the second group are turned fully on, a short circuit is achieved by the arrangement of parallel current paths. Separate but coordinated control signals are provided to turn on the control devices of the first group and increase their conduction toward saturation as a function of control input, and when fully on, or shortly before, to turn on the control devices of the second group and increase their conduction toward saturation as a function of the control input as that input continues to increase. Electronic means may be used to generate signals. The system may be used for 1-V characteristic measurements of solar arrays as well as for other load control purposes.

  17. New approaches to donor crossmatching and successful transplantation of highly sensitized patients.

    Science.gov (United States)

    Delmonico, F L; Fuller, A; Cosimi, A B; Tolkoff-Rubin, N; Russell, P S; Rodey, G E; Fuller, T C

    1983-12-01

    A class I HLA molecule may bear not only a private or unique determinant, but a shared, yet discrete, public epitope. These public determinants occur with a much higher frequency in the random donor population than the associated private determinants--and thus, are encountered more often in random donor blood transfusions and in renal transplantation. Sera from highly sensitized dialysis patients have been reported to contain a restricted number of antibodies to public determinants rather than a diverse array of antibodies directed against the private HLA-AB epitopes. As detailed in this report, comprehensive serum analysis of the public antibodies in highly sensitized transplant candidates has optimized identification of potential crossmatch-compatible donors and has avoided needless crossmatches. During the past two years, the incidence of renal transplantation from cadaveric donors to highly sensitized recipients has doubled at this institution. At 10-25 months following transplantation, 70% of these allografts are functioning. Private HLA class I antigen incompatibility was not a barometer for exclusion in the final donor crossmatch of these highly sensitized recipients. Furthermore, positive donor T cell crossmatches with sera obtained more than six months prior to transplantation may not represent an impediment to successful transplantation. We conclude that the approach of detailed antibody analysis can result in an improved outlook for successful transplantation of more dialysis patients who are highly sensitized to the class I HLA alloantigens.

  18. High Altitude Infrasound Measurements using Balloon-Borne Arrays

    Science.gov (United States)

    Bowman, D. C.; Johnson, C. S.; Gupta, R. A.; Anderson, J.; Lees, J. M.; Drob, D. P.; Phillips, D.

    2015-12-01

    For the last fifty years, almost all infrasound sensors have been located on the Earth's surface. A few experiments consisting of microphones on poles and tethered aerostats comprise the remainder. Such surface and near-surface arrays likely do not capture the full diversity of acoustic signals in the atmosphere. Here, we describe results from a balloon mounted infrasound array that reached altitudes of up to 38 km (the middle stratosphere). The balloon drifted at the ambient wind speed, resulting in a near total reduction in wind noise. Signals consistent with tropospheric turbulence were detected. A spectral peak in the ocean microbarom range (0.12 - 0.35 Hz) was present on balloon-mounted sensors but not on static infrasound stations near the flight path. A strong 18 Hz signal, possibly related to building ventilation systems, was observed in the stratosphere. A wide variety of other narrow band acoustic signals of uncertain provenance were present throughout the flight, but were absent in simultaneous recordings from nearby ground stations. Similar phenomena were present in spectrograms from the last balloon infrasound campaign in the 1960s. Our results suggest that the infrasonic wave field in the stratosphere is very different from that which is readily detectable on surface stations. This has implications for modeling acoustic energy transfer between the lower and upper atmosphere as well as the detection of novel acoustic signals that never reach the ground. Our work provides valuable constraints on a proposed mission to detect earthquakes on Venus using balloon-borne infrasound sensors.

  19. Growth of high-density horizontally aligned SWNT arrays using Trojan catalysts.

    Science.gov (United States)

    Hu, Yue; Kang, Lixing; Zhao, Qiuchen; Zhong, Hua; Zhang, Shuchen; Yang, Liangwei; Wang, Zequn; Lin, Jingjing; Li, Qingwen; Zhang, Zhiyong; Peng, Lianmao; Liu, Zhongfan; Zhang, Jin

    2015-01-20

    Single-walled carbon nanotube (SWNT)-based electronics have been regarded as one of the most promising candidate technologies to replace or supplement silicon-based electronics in the future. These applications require high-density horizontally aligned SWNT arrays. During the past decade, significant efforts have been directed towards growth of high-density SWNT arrays. However, obtaining SWNT arrays with suitable density and quality still remains a big challenge. Herein, we develop a rational approach to grow SWNT arrays with ultra-high density using Trojan catalysts. The density can be as high as 130 SWNTs μm(-1). Field-effect transistors fabricated with our SWNT arrays exhibit a record drive current density of -467.09 μA μm(-1) and an on-conductance of 233.55 μS μm(-1). Radio frequency transistors fabricated on these samples exhibit high intrinsic fT and fMAX of 6.94 and 14.01 GHz, respectively. These results confirm our high-density SWNT arrays are strong candidates for applications in electronics.

  20. Controlled synthesis of ZnO branched nanorod arrays by hierarchical solution growth and application in dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Fang Xiaoming, E-mail: cexmfang@scut.edu.cn; Peng Lihua; Shang Xiaoying; Zhang Zhengguo

    2011-07-29

    We demonstrate the controlled synthesis of ZnO branched nanorod arrays on fluorine-doped SnO{sub 2}-coated glass substrates by the hierarchical solution growth method. In the secondary growth, the concentration of Zn(NO{sub 3}){sub 2}/hexamethylenetetramine plays an important role in controlling the morphology of the branched nanorod arrays, besides that of diaminopropane used as a structure-directing agent to induce the growth of branches. The population density and morphology of the branched nanorod arrays depend on those of the nanorod arrays obtained from the primary growth, which can be modulated though the concentration of Zn(NO{sub 3}){sub 2}/hexamethylenetetramine in the primary growth solution. The dye-sensitized ZnO branched nanorod arrays exhibit much stronger optical absorption as compared with its corresponding primary nanorod arrays, suggesting that the addition of the branches improves light harvesting. The dye-sensitized solar cell based on the optimized ZnO branched nanorod array reaches a conversion efficiency of 1.66% under the light radiation of 1000 W/m{sup 2}. The branched nanorod arrays can also be applied in other application fields of ZnO.

  1. The high dynamic range pixel array detector (HDR-PAD): Concept and design

    Energy Technology Data Exchange (ETDEWEB)

    Shanks, Katherine S.; Philipp, Hugh T.; Weiss, Joel T.; Becker, Julian; Tate, Mark W. [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853 (United States); Gruner, Sol M., E-mail: smg26@cornell.edu [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853 (United States); Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853 (United States)

    2016-07-27

    Experiments at storage ring light sources as well as at next-generation light sources increasingly require detectors capable of high dynamic range operation, combining low-noise detection of single photons with large pixel well depth. XFEL sources in particular provide pulse intensities sufficiently high that a purely photon-counting approach is impractical. The High Dynamic Range Pixel Array Detector (HDR-PAD) project aims to provide a dynamic range extending from single-photon sensitivity to 10{sup 6} photons/pixel in a single XFEL pulse while maintaining the ability to tolerate a sustained flux of 10{sup 11} ph/s/pixel at a storage ring source. Achieving these goals involves the development of fast pixel front-end electronics as well as, in the XFEL case, leveraging the delayed charge collection due to plasma effects in the sensor. A first prototype of essential electronic components of the HDR-PAD readout ASIC, exploring different options for the pixel front-end, has been fabricated. Here, the HDR-PAD concept and preliminary design will be described.

  2. High-dynamic-range coherent diffractive imaging: ptychography using the mixed-mode pixel array detector

    Science.gov (United States)

    Giewekemeyer, Klaus; Philipp, Hugh T.; Wilke, Robin N.; Aquila, Andrew; Osterhoff, Markus; Tate, Mark W.; Shanks, Katherine S.; Zozulya, Alexey V.; Salditt, Tim; Gruner, Sol M.; Mancuso, Adrian P.

    2014-01-01

    Coherent (X-ray) diffractive imaging (CDI) is an increasingly popular form of X-ray microscopy, mainly due to its potential to produce high-resolution images and the lack of an objective lens between the sample and its corresponding imaging detector. One challenge, however, is that very high dynamic range diffraction data must be collected to produce both quantitative and high-resolution images. In this work, hard X-ray ptychographic coherent diffractive imaging has been performed at the P10 beamline of the PETRA III synchrotron to demonstrate the potential of a very wide dynamic range imaging X-ray detector (the Mixed-Mode Pixel Array Detector, or MM-PAD). The detector is capable of single photon detection, detecting fluxes exceeding 1 × 108 8-keV photons pixel−1 s−1, and framing at 1 kHz. A ptychographic reconstruction was performed using a peak focal intensity on the order of 1 × 1010 photons µm−2 s−1 within an area of approximately 325 nm × 603 nm. This was done without need of a beam stop and with a very modest attenuation, while ‘still’ images of the empty beam far-field intensity were recorded without any attenuation. The treatment of the detector frames and CDI methodology for reconstruction of non-sensitive detector regions, partially also extending the active detector area, are described. PMID:25178008

  3. CMOS Amperometric ADC With High Sensitivity, Dynamic Range and Power Efficiency for Air Quality Monitoring.

    Science.gov (United States)

    Li, Haitao; Boling, C Sam; Mason, Andrew J

    2016-08-01

    Airborne pollutants are a leading cause of illness and mortality globally. Electrochemical gas sensors show great promise for personal air quality monitoring to address this worldwide health crisis. However, implementing miniaturized arrays of such sensors demands high performance instrumentation circuits that simultaneously meet challenging power, area, sensitivity, noise and dynamic range goals. This paper presents a new multi-channel CMOS amperometric ADC featuring pixel-level architecture for gas sensor arrays. The circuit combines digital modulation of input currents and an incremental Σ∆ ADC to achieve wide dynamic range and high sensitivity with very high power efficiency and compact size. Fabricated in 0.5 [Formula: see text] CMOS, the circuit was measured to have 164 dB cross-scale dynamic range, 100 fA sensitivity while consuming only 241 [Formula: see text] and 0.157 [Formula: see text] active area per channel. Electrochemical experiments with liquid and gas targets demonstrate the circuit's real-time response to a wide range of analyte concentrations.

  4. Synthesis and application of TiO2 single-crystal nanorod arrays grown by multicycle hydrothermal for dye-sensitized solar cells

    Science.gov (United States)

    Zhu, Jian-Jing; Zhao, Yu-Long; Zhu, Lei; Gu, Xiu-Quan; Qiang, Ying-Huai

    2014-04-01

    TiO2 is a wide band gap semiconductor with important applications in photovoltaic cells. Vertically aligned TiO2 nanorod arrays (NRs) are grown on the fluorine-doped tin oxide (FTO) substrates by a multicycle hydrothermal synthesis process. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and selected-area electron diffraction (SAED). It is found that dye-sensitized solar cells (DSSCs) assembled by the as-prepared TiO2 single-crystal NRs exhibit different trends under the condition of different nucleation and growth concentrations. Optimum cell performance is obtained with high nucleation concentration and low growth cycle concentration. The efficiency enhancement is mainly attributed to the improved specific surface area of the nanorod.

  5. An offset-trimmable array of magnetic-field-sensitive MOS transistors (MAGFETs)

    DEFF Research Database (Denmark)

    Ning, Feng; Bruun, Erik

    1997-01-01

    Magnetic-field sensors can be implemented by the use of a magnetic-field-sensitive MOSFET structure, commonly referred to as a MAGFET. The MAGFET is a split-drain MOSFET where the difference between the drain currents is dependent on the magnetic field applied to the MAGFET. Unfortunately...

  6. A micropatterned cell array with an integrated oxygen-sensitive fluorescent membrane.

    Science.gov (United States)

    Montagne, Kevin; Komori, Kikuo; Yang, Fei; Tatsuma, Tetsu; Fujii, Teruo; Sakai, Yasuyuki

    2009-11-01

    We propose a simple method for producing micropatterned cell spots by photocatalytic lithography on a Pt porphyrin-based oxygen-sensitive polystyrene membrane that enables real-time imaging of oxygen consumption of patterned cell spots with sub-millimetre resolution.

  7. The fabrication of high sensitivity gold nanorod H2S gas sensors utilizing the highly uniform anodic aluminum oxide template

    Directory of Open Access Journals (Sweden)

    Chien-Yu Li

    2016-12-01

    Full Text Available Gold nanorod were fabricated using anodic alumina oxide template for H2S gas detection. The nanorod gas sensor exhibits high surface density and contact area, which can increase detection sensitivity. The anodic alumina oxide template contains an array of pores, with a width of 70 nm and a length of 27μm. Au nanorod were obtained through electro-deposition under a pulse bias of −1 V. The resistance of the Au nanorod was recorded upon exposure to various concentrations of H2S. The resistance could be attributed to the high electron affinity between sulfide and Au nanorod. Au–sulfide bonds provide strong bonding, which could alter the conductivity of the sensor. The gas sensor exhibits high sensitivity and short response time for H2S detection at room temperature.

  8. The fabrication of high sensitivity gold nanorod H2S gas sensors utilizing the highly uniform anodic aluminum oxide template

    Science.gov (United States)

    Li, Chien-Yu; Li, Ciao-Yu; Wu, You-Lin; Hsu, Chung-Ping; Lee, Ming-Ching; Houng, Mau-Phon

    2016-12-01

    Gold nanorod were fabricated using anodic alumina oxide template for H2S gas detection. The nanorod gas sensor exhibits high surface density and contact area, which can increase detection sensitivity. The anodic alumina oxide template contains an array of pores, with a width of 70 nm and a length of 27 μ m . Au nanorod were obtained through electro-deposition under a pulse bias of -1 V. The resistance of the Au nanorod was recorded upon exposure to various concentrations of H2S. The resistance could be attributed to the high electron affinity between sulfide and Au nanorod. Au-sulfide bonds provide strong bonding, which could alter the conductivity of the sensor. The gas sensor exhibits high sensitivity and short response time for H2S detection at room temperature.

  9. A High-throughput Genomic Tool: Diversity Array Technology Complementary for Rice Genotyping

    Institute of Scientific and Technical Information of China (English)

    Yong Xie; Kenneth McNally; Cheng-Yun Li; Hei Leung; You-Yong Zhu

    2006-01-01

    Diversity array technology (DArTTM) was a genotyping tool characterized gel-independent and high throughput.The main purpose of present study is to validate DArT for rice (Oryza sativa L.)genotyping in a high throughput manner. Technically, the main objective was to generate a rice general purpose gene pool, and optimize this genomic tool in order to evaluate rice germplasm genetic diversity. To achieve this, firstly, a generalpurpose DArT array was developed. Ten representatives from 24 varieties were hybridized with the general-purpose array to determine the informativeness of the clones printed on the array. The informative 1 152 clones were re-arrayed on a slide and used to fingerprint 17 of 24 germplasms. Hybridizing targets prepared from the germplasm to be assayed to the DNA array gave DNA fingerprints of germplasms. Raw data were normalized and transformed into binary data, which were then analyzed by using NTSYSpc (Numerical taxonomy system for cluster and ordination analysis, v. 2.02j) software package. The graphically displayed dendrogram derived from the array experimental data was matched with simple Sequence repeats genotyping outline and varieties' pedigree deviation of the different varieties. Considering DArT is a sequence-independent genotyping approach, it will be applied in studies of the genetic diversity and the gene mapping of diverse of organisms, especially for those crops with less-developed molecular markers.

  10. High-Precision Dispensing of Nanoliter Biofluids on Glass Pedestal Arrays for Ultrasensitive Biomolecule Detection.

    Science.gov (United States)

    Chen, Xiaoxiao; Liu, Yang; Xu, QianFeng; Zhu, Jing; Poget, Sébastien F; Lyons, Alan M

    2016-05-04

    Precise dispensing of nanoliter droplets is necessary for the development of sensitive and accurate assays, especially when the availability of the source solution is limited. Conventional approaches are limited by imprecise positioning, large shear forces, surface tension effects, and high costs. To address the need for precise and economical dispensing of nanoliter volumes, we developed a new approach where the dispensed volume is dependent on the size and shape of defined surface features, thus freeing the dispensing process from pumps and fine-gauge needles requiring accurate positioning. The surface we fabricated, called a nanoliter droplet virtual well microplate (nVWP), achieves high-precision dispensing (better than ±0.5 nL or ±1.6% at 32 nL) of 20-40 nL droplets using a small source drop (3-10 μL) on isolated hydrophilic glass pedestals (500 μm on a side) bonded to arrays of polydimethylsiloxane conical posts. The sharp 90° edge of the glass pedestal pins the solid-liquid-vapor triple contact line (TCL), averting the wetting of the glass sidewalls while the fluid is prevented from receding from the edge. This edge creates a sufficiently large energy barrier such that microliter water droplets can be poised on the glass pedestals, exhibiting contact angles greater >150°. This approach relieves the stringent mechanical alignment tolerances required for conventional dispensing techniques, shifting the control of dispensed volume to the area circumscribed by the glass edge. The effects of glass surface chemistry and dispense velocity on droplet volume were studied using optical microscopy and high-speed video. Functionalization of the glass pedestal surface enabled the selective adsorption of specific peptides and proteins from synthetic and natural biomolecule mixtures, such as venom. We further demonstrate how the nVWP dispensing platform can be used for a variety of assays, including sensitive detection of proteins and peptides by fluorescence

  11. Design optimization of high pressure and high temperature piezoresistive pressure sensor for high sensitivity

    Science.gov (United States)

    Niu, Zhe; Zhao, Yulong; Tian, Bian

    2014-01-01

    This paper describes a design method for optimizing sensitivity of piezoresistive pressure sensor in high-pressure and high-temperature environment. In order to prove the method, a piezoresistive pressure sensor (HPTSS) is designed. With the purpose of increasing sensitivity and to improve the measurement range, the piezoresistive sensor adopts rectangular membrane and thick film structure. The configuration of piezoresistors is arranged according to the characteristic of the rectangular membrane. The structure and configuration of the sensor chip are analyzed theoretically and simulated by the finite element method. This design enables the sensor chip to operate in high pressure condition (such as 150 MPa) with a high sensitivity and accuracy. The silicon on insulator wafer is selected to guarantee the thermo stability of the sensor chip. In order to optimize the fabrication and improve the yield of production, an electric conduction step is devised. Series of experiments demonstrates a favorable linearity of 0.13% and a high accuracy of 0.48%. And the sensitivity of HTPSS is about six times as high as a conventional square-membrane sensor chip in the experiment. Compared with the square-membrane pressure sensor and current production, the strength of HPTTS lies in sensitivity and measurement. The performance of the HPTSS indicates that it could be an ideal candidate for high-pressure and high-temperature sensing in real application.

  12. Design optimization of high pressure and high temperature piezoresistive pressure sensor for high sensitivity.

    Science.gov (United States)

    Niu, Zhe; Zhao, Yulong; Tian, Bian

    2014-01-01

    This paper describes a design method for optimizing sensitivity of piezoresistive pressure sensor in high-pressure and high-temperature environment. In order to prove the method, a piezoresistive pressure sensor (HPTSS) is designed. With the purpose of increasing sensitivity and to improve the measurement range, the piezoresistive sensor adopts rectangular membrane and thick film structure. The configuration of piezoresistors is arranged according to the characteristic of the rectangular membrane. The structure and configuration of the sensor chip are analyzed theoretically and simulated by the finite element method. This design enables the sensor chip to operate in high pressure condition (such as 150 MPa) with a high sensitivity and accuracy. The silicon on insulator wafer is selected to guarantee the thermo stability of the sensor chip. In order to optimize the fabrication and improve the yield of production, an electric conduction step is devised. Series of experiments demonstrates a favorable linearity of 0.13% and a high accuracy of 0.48%. And the sensitivity of HTPSS is about six times as high as a conventional square-membrane sensor chip in the experiment. Compared with the square-membrane pressure sensor and current production, the strength of HPTTS lies in sensitivity and measurement. The performance of the HPTSS indicates that it could be an ideal candidate for high-pressure and high-temperature sensing in real application.

  13. Novel design of multicapillary arrays for high-throughput DNA sequencing.

    Science.gov (United States)

    Tsupryk, Andriy; Gorbovitski, Michael; Kabotyanski, Evgeni A; Gorfinkel, Vera

    2006-07-01

    A novel approach to design and optimize linear multicapillary arrays (LMCAs) for high-throughput DNA sequencing is proposed. A significant increase in the number of capillary lanes is obtained due to the use of composite insertions alternately placed between working capillaries of the array and a specific combination of refractive indices of the DNA separation matrix, capillary glass, the insertions and a medium which surrounds the capillary array. Theoretical and experimental studies showed that in conjunction with a dual-side laser illumination scheme, the proposed LMCA design allows a simultaneous uniform irradiation of as many as 550 working capillaries.

  14. High-Throughput DNA Array for SNP Detection of KRAS Gene Using a Centrifugal Microfluidic Device.

    Science.gov (United States)

    Sedighi, Abootaleb; Li, Paul C H

    2016-01-01

    Here, we describe detection of single nucleotide polymorphism (SNP) in genomic DNA samples using a NanoBioArray (NBA) chip. Fast DNA hybridization is achieved in the chip when target DNAs are introduced to the surface-arrayed probes using centrifugal force. Gold nanoparticles (AuNPs) are used to assist SNP detection at room temperature. The parallel setting of sample introduction in the spiral channels of the NBA chip enables multiple analyses on many samples, resulting in a technique appropriate for high-throughput SNP detection. The experimental procedure, including chip fabrication, probe array printing, DNA amplification, hybridization, signal detection, and data analysis, is described in detail.

  15. Measuring High-Precision Astrometry with the Infrared Array Camera on the Spitzer Space Telescope

    Science.gov (United States)

    Esplin, T. L.; Luhman, K. L.

    2016-01-01

    The Infrared Array Camera (IRAC) on the Spitzer Space Telescope currently offers the greatest potential for high-precision astrometry of faint mid-IR sources across arcminute-scale fields, which would be especially valuable for measuring parallaxes of cold brown dwarfs in the solar neighborhood and proper motions of obscured members of nearby star-forming regions. To more fully realize IRAC's astrometric capabilities, we have sought to minimize the largest sources of uncertainty in astrometry with its 3.6 and 4.5 μm bands. By comparing different routines that estimate stellar positions, we have found that Point Response Function (PRF) fitting with the Spitzer Science Center's Astronomical Point Source Extractor produces both the smallest systematic errors from varying intra-pixel sensitivity and the greatest precision in measurements of positions. In addition, self-calibration has been used to derive new 7th and 8th order distortion corrections for the 3.6 and 4.5 μm arrays of IRAC, respectively. These corrections are suitable for data throughout the mission of Spitzer when a time-dependent scale factor is applied to the corrections. To illustrate the astrometric accuracy that can be achieved by combining PRF fitting with our new distortion corrections, we have applied them to archival data for a nearby star-forming region, arriving at total astrometric errors of ∼20 and 70 mas at signal to noise ratios of 100 and 10, respectively. Based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA.

  16. Error, reproducibility and sensitivity: a pipeline for data processing of Agilent oligonucleotide expression arrays

    Directory of Open Access Journals (Sweden)

    Posch Wilfried

    2010-06-01

    Full Text Available Abstract Background Expression microarrays are increasingly used to obtain large scale transcriptomic information on a wide range of biological samples. Nevertheless, there is still much debate on the best ways to process data, to design experiments and analyse the output. Furthermore, many of the more sophisticated mathematical approaches to data analysis in the literature remain inaccessible to much of the biological research community. In this study we examine ways of extracting and analysing a large data set obtained using the Agilent long oligonucleotide transcriptomics platform, applied to a set of human macrophage and dendritic cell samples. Results We describe and validate a series of data extraction, transformation and normalisation steps which are implemented via a new R function. Analysis of replicate normalised reference data demonstrate that intrarray variability is small (only around 2% of the mean log signal, while interarray variability from replicate array measurements has a standard deviation (SD of around 0.5 log2 units ( 6% of mean. The common practise of working with ratios of Cy5/Cy3 signal offers little further improvement in terms of reducing error. Comparison to expression data obtained using Arabidopsis samples demonstrates that the large number of genes in each sample showing a low level of transcription reflect the real complexity of the cellular transcriptome. Multidimensional scaling is used to show that the processed data identifies an underlying structure which reflect some of the key biological variables which define the data set. This structure is robust, allowing reliable comparison of samples collected over a number of years and collected by a variety of operators. Conclusions This study outlines a robust and easily implemented pipeline for extracting, transforming normalising and visualising transcriptomic array data from Agilent expression platform. The analysis is used to obtain quantitative estimates of

  17. A highly sensitive colorimetric and ratiometric sensor for fluoride ion

    Institute of Scientific and Technical Information of China (English)

    Zhao Wu Xu; Jin Tang; He Tian

    2008-01-01

    A new benzoimidazole-naphthalimide derivative 4 was synthesized and its photophysical properties were studied.This compound showed highly selectively and sensitive colorimetric and ratiometric sensing ability for fluoride anion.

  18. Dark matter substructure modelling and sensitivity of the Cherenkov Telescope Array to Galactic dark halos

    Science.gov (United States)

    Hütten, M.; Combet, C.; Maier, G.; Maurin, D.

    2016-09-01

    Hierarchical structure formation leads to a clumpy distribution of dark matter in the Milky Way. These clumps are possible targets to search for dark matter annihilation with present and future γ-ray instruments. Many uncertainties exist on the clump distribution, leading to disputed conclusions about the expected number of detectable clumps and the ensuing limits that can be obtained from non-detection. In this paper, we use the CLUMPY code to simulate thousands of skymaps for several clump distributions. This allows us to statistically assess the typical properties (mass, distance, angular size, luminosity) of the detectable clumps. Varying parameters of the clump distributions allows us to identify the key quantities to which the number of detectable clumps is the most sensitive. Focusing our analysis on two extreme clump configurations, yet consistent with results from numerical simulations, we revisit and compare various calculations made for the Fermi-LAT instrument, in terms of number of dark clumps expected and the angular power spectrum for the Galactic signal. We then focus on the prospects of detecting dark clumps with the future CTA instrument, for which we make a detailed sensitivity analysis using open-source CTA software. Based on a realistic scenario for the foreseen CTA extragalactic survey, and accounting for a post-trial sensitivity in the survey, we show that we obtain competitive and complementary limits to those based on long observation of a single bright dwarf spheroidal galaxy.

  19. Dark matter substructure modelling and sensitivity of the Cherenkov Telescope Array to Galactic dark halos

    Energy Technology Data Exchange (ETDEWEB)

    Huetten, M. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Humboldt Univ. Berlin (Germany); Combet, C.; Maurin, D. [Grenoble-Alpes Univ., CNRS/IN2P3, Grenoble (France). LPSC; Maier, G. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2016-07-15

    Hierarchical structure formation leads to a clumpy distribution of dark matter in the Milky Way. These clumps are possible targets to search for dark matter annihilation with present and future γ-ray instruments. Many uncertainties exist on the clump distribution, leading to disputed conclusions about the expected number of detectable clumps and the ensuing limits that can be obtained from non-detection. In this paper, we use the CLUMPY code to simulate thousands of skymaps for several clump distributions. This allows us to statistically assess the typical properties (mass, distance, angular size, luminosity) of the detectable clumps. Varying parameters of the clump distributions allows us to identify the key quantities to which the number of detectable clumps is the most sensitive. Focusing our analysis on two extreme clump configurations, yet consistent with results from numerical simulations, we revisit and compare various calculations made for the Fermi-LAT instrument, in terms of number of dark clumps expected and the angular power spectrum for the Galactic signal. We then focus on the prospects of detecting dark clumps with the future CTA instrument, for which we make a detailed sensitivity analysis using open-source CTA software. Based on a realistic scenario for the foreseen CTA extragalactic survey, and accounting for a post-trial sensitivity in the survey, we show that we obtain competitive and complementary limits to those based on long observation of a single bright dwarf spheroidal galaxy.

  20. SU-E-T-415: An Ionization Chamber Array with High Spatial Resolution for External Beam Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Togno, M [Klinikum rechts der Isar, Technische Universitaet Muenchen, Muenchen (Germany); IBA Dosimetry, Schwarzenbruck (Germany); Wilkens, J [Klinikum rechts der Isar, Technische Universitaet Muenchen, Muenchen (Germany); Menichelli, D [IBA Dosimetry, Schwarzenbruck (Germany)

    2014-06-01

    Purpose: To characterize an ionization chamber array technology with high spatial resolution and high charge collection efficiency for external beam radiotherapy. Methods: The prototype under test is a linear array of air vented ionization chambers developed by IBA Dosimetry, consisting of 80 pixels with 3.5mm spatial resolution and 4mm{sup 3} sensitive volume. The detector was characterized in a plastic phantom with {sup 60} Co radiation and MV X-rays from an ELEKTA Agility LINAC (with flattened and unflattened beam qualities). Bias voltage was varied in order to evaluate charge collection efficiency. A commercial array of ionization chambers (MatriXX Evolution, IBA Dosimetry) and an amorphous silicon flat panel in direct conversion configuration were used as references. Results: Repeatability (0.4%) and stability under continuous gamma irradiation (0.3%) are very good, in spite of low active volume and sensitivity (∼200pC/Gy). Charge collection efficiency is higher than 99% already at 150V with ∼2mGy dose per pulse, leading to a ±1.1% sensitivity change with dose per pulse in the range 0.09-2mGy (covering all flattened and unflattened applications). Measured dose profiles are in agreement with MatriXX for fields larger than 2×2cm{sup 2}, in which case the linear array offers a much better characterization of the penumbra region. Down to 1×1cm{sup 2}, measured profiles are in very good agreement with the flat panel. Conclusion: The array represents a valuable tool for the characterization of treatment fields in which high spatial resolution is required, together with the dosimetric performance of air vented ionization chambers. Such a technology would be particularly valuable in association with advanced treatment modalities such as rotational radiotherapy, stereotactic treatments (even with unflattened beam qualities) and proton therapy, due to the insensitivity of the chambers on dose per pulse. In the future, a two dimensional prototype based on this

  1. Fabrication and structural characterization of highly ordered titania nanotube arrays

    Science.gov (United States)

    Shi, Hongtao; Ordonez, Rosita

    Titanium (Ti) dioxide nanotubes have drawn much attention in the past decade due to the fact that titania is an extremely versatile material with a variety of technological applications. Anodizing Ti in different electrolytes has proved to be quite successful so far in creating the nanotubes, however, their degree of order is still not nearly as good as nanoporous anodic alumina. In this work, we first deposit a thin layer of aluminum (Al) onto electropolished Ti substrates, using thermal evaporation. Such an Al layer is then anodized in 0.3 M oxalic acid, forming an ordered nanoporous alumina mask on top of Ti. Afterwards, the anodization of Ti is accomplished at 20 V in solutions containing 1 M NaH2PO4 and 0.5% HF or H2SO4, which results in the creation of ordered titania nanotube arrays. The inner pore diameter of the nanotubes can be tuned from ~50 nm to ~75 nm, depending on the anodization voltage applied to Al or Ti. X-ray diffractometry shows the as-grown titania nanotubes are amorphous. Samples annealed at different temperatures in ambient atmosphere will be also reported.

  2. Preparation of electrochemically active silicon nanotubes in highly ordered arrays

    Directory of Open Access Journals (Sweden)

    Tobias Grünzel

    2013-10-01

    Full Text Available Silicon as the negative electrode material of lithium ion batteries has a very large capacity, the exploitation of which is impeded by the volume changes taking place upon electrochemical cycling. A Si electrode displaying a controlled porosity could circumvent the difficulty. In this perspective, we present a preparative method that yields ordered arrays of electrochemically competent silicon nanotubes. The method is based on the atomic layer deposition of silicon dioxide onto the pore walls of an anodic alumina template, followed by a thermal reduction with lithium vapor. This thermal reduction is quantitative, homogeneous over macroscopic samples, and it yields amorphous silicon and lithium oxide, at the exclusion of any lithium silicides. The reaction is characterized by spectroscopic ellipsometry for thin silica films, and by nuclear magnetic resonance and X-ray photoelectron spectroscopy for nanoporous samples. After removal of the lithium oxide byproduct, the silicon nanotubes can be contacted electrically. In a lithium ion electrolyte, they then display the electrochemical waves also observed for other bulk or nanostructured silicon systems. The method established here paves the way for systematic investigations of how the electrochemical properties (capacity, charge/discharge rates, cyclability of nanoporous silicon negative lithium ion battery electrode materials depend on the geometry.

  3. Two-dimensional Josephson junction arrays coupled through a high-Q cavity

    DEFF Research Database (Denmark)

    Filatrella, G.; Pedersen, Niels Falsig; Wiesenfeld, K.

    2001-01-01

    the cavity. The highly resonant cavity induces synchronized behavior, which is qualitatively different than what is familiar from other studies on nonlinear oscillator arrays, for example the Kuramoto model. We also address the effects of disorder, as well as the role of detuning between the spontaneous...... emission frequency of the junctions and the cavity resonant frequency. We show with a simple argument that we can predict the scaling behavior of disorder with the size of the array. The consequences for the design of microwave oscillators in the Gigahertz region are discussed......The problem of disordered two-dimensional arrays of underdamped Josephson junctions is addressed. Our simulations show that when coupled to a high-Q cavity, the array exhibits synchronized behavior, and the power emitted can be considerably increased once enough junctions are activated to pump...

  4. High-resolution microcontact printing and transfer of massive arrays of microorganisms on planar and compartmentalized nanoporous aluminium oxide

    NARCIS (Netherlands)

    Ingham, C.J.; Bomer, J.; Sprenkels, A.; Berg, van der A.; Vos, de W.M.; Hylckama, van J.

    2010-01-01

    Handling microorganisms in high throughput and their deployment into miniaturized platforms presents significant challenges. Contact printing can be used to create dense arrays of viable microorganisms. Such "living arrays", potentially with multiple identical replicates, are useful in the selection

  5. High-resolution microcontact printing and transfer of massive arrays of microorganisms on planar and compartmentalized nanoporous aluminium oxide

    NARCIS (Netherlands)

    Ingham, Colin; Bomer, Johan; Sprenkels, Ad; Berg, van den Albert; Vos, de Willem; Hylckama Vlieg, van Johan

    2010-01-01

    Handling microorganisms in high throughput and their deployment into miniaturized platforms presents significant challenges. Contact printing can be used to create dense arrays of viable microorganisms. Such "living arrays'', potentially with multiple identical replicates, are useful in the selectio

  6. The Baryon Acoustic Oscillation Broadband and Broad-beam Array: Design Overview and Sensitivity Forecasts

    CERN Document Server

    Pober, Jonathan C; DeBoer, David R; McDonald, Patrick; McQuinn, Matthew; Aguirre, James E; Ali, Zaki; Bradley, Richard F; Chang, Tzu-Ching; Morales, Miguel F

    2012-01-01

    This work describes a new instrument optimized for a detection of the neutral hydrogen 21cm power spectrum between redshifts of 0.5-1.5: the Baryon Acoustic Oscillation Broadband and Broad-beam (BAOBAB) Array. BAOBAB will build on the efforts of a first generation of 21cm experiments which are targeting a detection of the signal from the Epoch of Reionization at z ~ 10. At z ~ 1, the emission from neutral hydrogen in self-shielded overdense halos also presents an accessible signal, since the dominant, synchrotron foreground emission is considerably fainter than at redshift 10. The principle science driver for these observations are Baryon Acoustic Oscillations in the matter power spectrum which have the potential to act as a standard ruler and constrain the nature of dark energy. BAOBAB will fully correlate dual-polarization antenna tiles over the 600-900MHz band with a frequency resolution of 300 kHz and a system temperature of 50K. The number of antennas will grow in staged deployments, and reconfigurations...

  7. Double-layer electrode based on TiO2 nanotubes arrays for enhancing photovoltaic properties in dye-sensitized solar cells.

    Science.gov (United States)

    He, Zuoli; Que, Wenxiu; Sun, Peng; Ren, Jiangbo

    2013-12-26

    The present work reports a rapid and facile method to fabricate a novel double-layer TiO2 photoanode, which is based on highly ordered TiO2 nanotube arrays and monodispersive scattering microspheres. This double-layer TiO2 sphere/TNTA photoanode have got many unique structural and optical properties from TiO2 scattering microspheres, such as high specific surface area, multiple interparticle scattering, and efficient light-harvesting. Results indicate that this as-fabricated double-layer TiO2 sphere/TNTA front-illumination dye-sensitized solar cell, which is fabricated from the TiO2 nanotube arrays with a 17.4 μm length after TiCl4 treatment, exhibits a pronounced power conversion efficiency of 7.24% under an AM1.5 G irradiation, which can be attributed to the increased incident photon-to-current conversion and light-harvesting efficiency.

  8. High-resolution Very Large Array observations of 18 MIPSGAL bubbles

    CERN Document Server

    Ingallinera, Adriano; Leto, Paolo; Umana, Grazia; Buemi, Carla; Bufano, Filomena; Agliozzo, Claudia; Riggi, Simone; Flagey, Nicolas; Silva, Kevin; Cerrigone, Luciano; Cavallaro, Francesco

    2016-01-01

    We present radio observations of 18 MIPSGAL bubbles performed at 5 GHz (6 cm) with the Karl G. Jansky Very Large Array in configuration B and BnA. The observations were aimed at understanding what kind of information high-resolution and high-sensitivity radio maps can supply on the circumstellar envelopes of different kinds of evolved stars and what their comparison with infrared images with similar resolution can tell us. We found that the 18 bubbles can be grouped into five categories according to their radio morphology. The three bubbles presenting a central point source in the radio images all correspond to luminous blue variable star candidates. Eleven bubbles show an elliptical shape and the total lack of a central object in the radio, and are likely associated with planetary nebulae. Under this assumption we derive their distance, their ionized mass and their distribution on the Galactic plane. We discuss the possibility that the MIPSGAL bubbles catalogue (428 objects) may contain a large fraction of a...

  9. Influence of TiO2 Nanorod Arrays on the Bilayered Photoanode for Dye-Sensitized Solar Cells

    Science.gov (United States)

    Cao, Ya; Li, Zhen; Wang, Yang; Zhang, Tao; Li, Yinchang; Liu, Xueqin; Li, Fei

    2016-10-01

    A TiO2 bilayered structure consisting of TiO2 nanoparticles (TiO2NP) as an overlayer and single-crystal rutile TiO2 nanorods (TiO2 NRs) as an underlayer on a transparent conductive fluorine-doped tin oxide substrate was designed as the photoanode of dye-sensitized solar cells (DSSCs) through a facile hydrothermal treatment followed by a doctor-blade method. DSSCs based on the hierarchical TiO2 nano-architecture photoelectrode shows a power conversion efficiency of 7.39% because the relatively large specific surface area of TiO2NP increased the dye absorption, and oriented one-dimensional TiO2 NRs enhanced the light harvesting capability, accelerating interfacial electron transport. In particular, we observed the growth morphology of the TiO2 nanorod arrays in the bilayered photoanode and the influence of the whole solar cell. The result indicated that the TiO2 NRs layer clearly impacted the photoelectron chemical properties, while the vertical and intensive nanorod arrays significantly increased their performance.

  10. Silicon-based antenna-coupled polarization-sensitive millimeter-wave bolometer arrays for cosmic microwave background instruments

    Science.gov (United States)

    Rostem, Karwan; Ali, Aamir; Appel, John W.; Bennett, Charles L.; Brown, Ari; Chang, Meng-Ping; Chuss, David T.; Colazo, Felipe A.; Costen, Nick; Denis, Kevin L.; Essinger-Hileman, Tom; Hu, Ron; Marriage, Tobias A.; Moseley, Samuel H.; Stevenson, Thomas R.; U-Yen, Kongpop; Wollack, Edward J.; Xu, Zhilei

    2016-07-01

    We describe feedhorn-coupled polarization-sensitive detector arrays that utilize monocrystalline silicon as the dielectric substrate material. Monocrystalline silicon has a low-loss tangent and repeatable dielectric constant, characteristics that are critical for realizing efficient and uniform superconducting microwave circuits. An additional advantage of this material is its low specific heat. In a detector pixel, two Transition-Edge Sensor (TES) bolometers are antenna-coupled to in-band radiation via a symmetric planar orthomode transducer (OMT). Each orthogonal linear polarization is coupled to a separate superconducting microstrip transmission line circuit. On-chip filtering is employed to both reject out-of-band radiation from the upper band edge to the gap frequency of the niobium superconductor, and to flexibly define the bandwidth for each TES to meet the requirements of the application. The microwave circuit is compatible with multi-chroic operation. Metalized silicon platelets are used to define the backshort for the waveguide probes. This micro-machined structure is also used to mitigate the coupling of out-of-band radiation to the microwave circuit. At 40 GHz, the detectors have a measured efficiency of ˜90%. In this paper, we describe the development of the 90 GHz detector arrays that will be demonstrated using the Cosmology Large Angular Scale Surveyor (CLASS) ground-based telescope.

  11. High-efficiency microstructured semiconductor neutron detectors that are arrayed, dual-integrated, and stacked

    Energy Technology Data Exchange (ETDEWEB)

    Bellinger, Steven L., E-mail: slb3888@ksu.edu [Department of Mechanical and Nuclear Engineering, Kansas State University, Manhattan, KS 66506 (United States); Fronk, Ryan G. [Department of Mechanical and Nuclear Engineering, Kansas State University, Manhattan, KS 66506 (United States); Sobering, Timothy J. [Electronics Design Laboratory, Kansas State University, Manhattan, KS 66506 (United States); McGregor, Douglas S. [Department of Mechanical and Nuclear Engineering, Kansas State University, Manhattan, KS 66506 (United States)

    2012-07-15

    Silicon diodes with large aspect ratio 3D microstructures backfilled with {sup 6}LiF show a significant increase in neutron detection efficiency beyond that of conventional thin-film coated planar devices. Described in this work are advancements in the technology using detector stacking methods and summed-detector 6 Multiplication-Sign 6-element arraying methods to dramatically increase the sensitivity to thermal neutrons. The intrinsic detection efficiency of the 6 Multiplication-Sign 6 array for normal-incident 0.0253 eV neutrons was found 6.8% compared against a calibrated {sup 3}He proportional counter. - Highlights: Black-Right-Pointing-Pointer Solid-state semiconductor neutron detectors utilizing {sup 6}LiF. Black-Right-Pointing-Pointer Large aspect ratio 3D microstructured silicon diodes. Black-Right-Pointing-Pointer Arrayed solid-state semiconductor neutron detectors.

  12. Degradation of Solar Array Components in a Combined UV/VUV High Temperature Test Environment

    Directory of Open Access Journals (Sweden)

    Nömayr Christel

    2017-01-01

    A design verification test under UV/VUV conditions of sun exposed materials and technologies on component level is presented which forms part of the overall verification and qualification of the solar array design of the MTM and MPO. The test concentrates on the self-contamination aspects and the resulting performance losses of the solar array under high intensity and elevated temperature environment representative for the photovoltaic assembly (PVA.

  13. HIGH-PRECISION DETERMINATION OF THE ANGULAR POSITION FOR POINT LIGHT SOURCE WITH CCD-ARRAYS

    Directory of Open Access Journals (Sweden)

    Y. G. Lebedko

    2015-05-01

    Full Text Available Subject of study. A method of angular position measuring for point light source in the system with CCD arrays is proposed by converting of angle – time – code in low light conditions and at high signal / noise ratio. Assessment of the method potential accuracy is given. It is determined by instrumental irremovable random errors of measurement in terms of optimal processing of incoming information with a single reading it with CCD – arrays. Method. This work introduces an optoelectronic system circuit with CCD arrays with stretched sensing elements and a point of reference for angular position measuring. In this case the arrays have images projections of both the reference point source and the target point source, which angular position is measured with high precision. From the CCD array output the signals arrive at an optimal (or apt linear filter, and then to the signal peak position detection circuit. The scheme provides minimum error due to the influence of noise. Pulse edges, corresponding to the signals maximum, make a time interval filled with high-frequency counting pulses. The number of pulses in this interval will correspond to the measured angular position of the target point source. Main results. Analysis of random errors has been carried out in terms of statistical decision theory. Analysis takes into account the spectral function of the signals defined by transfer functions of the optical system and a CCD array as an image analyzer. Research of measurement accuracy is carried out depending on the clock frequency of reading information from CCD arrays for different values of signal-to-noise ratio. It has been shown that even with a single readout with CCD array by the proposed opto-electronic circuit measuring error does not exceed 0.01 of the sensing element size. Practical significance. The results are usable in high-precision measuring opto-electronic systems of star sensors for determining the angular position of the low

  14. Silicon-Based Antenna-Coupled Polarization-Sensitive Millimeter-Wave Bolometer Arrays for Cosmic Microwave Background Instruments

    CERN Document Server

    Rostem, Karwan; Appel, John W; Bennett, Charles L; Brown, Ari; Chang, Meng-Ping; Chuss, David T; Colazo, Felipe A; Costen, Nick; Denis, Kevin L; Essinger-Hileman, Tom; Hu, Ron; Marriage, Tobias A; Moseley, Samuel H; Stevenson, Thomas R; U-Yen, Kongpop; Wollack, Edward J; Xu, Zhilei

    2016-01-01

    We describe feedhorn-coupled polarization-sensitive detector arrays that utilize monocrystalline silicon as the dielectric substrate material. Monocrystalline silicon has a low-loss tangent and repeatable dielectric constant, characteristics that are critical for realizing efficient and uniform superconducting microwave circuits. An additional advantage of this material is its low specific heat. In a detector pixel, two Transition-Edge Sensor (TES) bolometers are antenna-coupled to in-band radiation via a symmetric planar orthomode transducer (OMT). Each orthogonal linear polarization is coupled to a separate superconducting microstrip transmission line circuit. On-chip filtering is employed to both reject out-of-band radiation from the upper band edge to the gap frequency of the niobium superconductor, and to flexibly define the bandwidth for each TES to meet the requirements of the application. The microwave circuit is compatible with multi-chroic operation. Metalized silicon platelets are used to define th...

  15. Rectangular bunched rutile TiO2 nanorod arrays grown on carbon fiber for dye-sensitized solar cells.

    Science.gov (United States)

    Guo, Wenxi; Xu, Chen; Wang, Xue; Wang, Sihong; Pan, Caofeng; Lin, Changjian; Wang, Zhong Lin

    2012-03-07

    Because of their special application in photovoltaics, the growth of one-dimensional single-crystalline TiO(2) nanostructures on a flexible substrate is receiving intensive attention. Here we present a study of rectangular bunched TiO(2) nanorod (NR) arrays grown on carbon fibers (CFs) from titanium by a "dissolve and grow" method. After a corrosion process in a strong acid solution, every single nanorod is etched into a number of small nanowires. Tube-shaped dye-sensitized solar cells are fabricated by using etched TiO(2) NRs-coated CFs as the photoanode. An absolute energy conversion efficiency of 1.28% has been demonstrated under 100 mW cm(-2) AM 1.5 illumination. This work demonstrates an innovative method for growing bunched TiO(2) NRs on flexible substrates that can be applied in flexible devices for energy harvesting and storage.

  16. High-Angular-Resolution and High-Sensitivity Science Enabled by Beamformed ALMA

    CERN Document Server

    Fish, Vincent; Anderson, James; Asada, Keiichi; Baudry, Alain; Broderick, Avery; Carilli, Chris; Colomer, Francisco; Conway, John; Dexter, Jason; Doeleman, Sheperd; Eatough, Ralph; Falcke, Heino; Frey, Sándor; Gabányi, Krisztina; Gálvan-Madrid, Roberto; Gammie, Charles; Giroletti, Marcello; Goddi, Ciriaco; Gómez, Jose L; Hada, Kazuhiro; Hecht, Michael; Honma, Mareki; Humphreys, Elizabeth; Impellizzeri, Violette; Johannsen, Tim; Jorstad, Svetlana; Kino, Motoki; Körding, Elmar; Kramer, Michael; Krichbaum, Thomas; Kudryavtseva, Nadia; Laing, Robert; Lazio, Joseph; Loeb, Abraham; Lu, Ru-Sen; Maccarone, Thomas; Marscher, Alan; Mart'ı-Vidal, Iván; Martins, Carlos; Matthews, Lynn; Menten, Karl; Miller, Jon; Miller-Jones, James; Mirabel, Félix; Muller, Sebastien; Nagai, Hiroshi; Nagar, Neil; Nakamura, Masanori; Paragi, Zsolt; Pradel, Nicolas; Psaltis, Dimitrios; Ransom, Scott; Rodr'\\iguez, Luis; Rottmann, Helge; Rushton, Anthony; Shen, Zhi-Qiang; Smith, David; Stappers, Benjamin; Takahashi, Rohta; Tarchi, Andrea; Tilanus, Remo; Verbiest, Joris; Vlemmings, Wouter; Walker, R Craig; Wardle, John; Wiik, Kaj; Zackrisson, Erik; Zensus, J Anton

    2013-01-01

    An international consortium is presently constructing a beamformer for the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile that will be available as a facility instrument. The beamformer will aggregate the entire collecting area of the array into a single, very large aperture. The extraordinary sensitivity of phased ALMA, combined with the extremely fine angular resolution available on baselines to the Northern Hemisphere, will enable transformational new very long baseline interferometry (VLBI) observations in Bands 6 and 7 (1.3 and 0.8 mm) and provide substantial improvements to existing VLBI arrays in Bands 1 and 3 (7 and 3 mm). The ALMA beamformer will have impact on a variety of scientific topics, including accretion and outflow processes around black holes in active galactic nuclei (AGN), tests of general relativity near black holes, jet launch and collimation from AGN and microquasars, pulsar and magnetar emission processes, the chemical history of the universe and the evolution of fundame...

  17. Dye-sensitized solar cells with vertically aligned TiO2 nanowire arrays grown on carbon fibers.

    Science.gov (United States)

    Cai, Xin; Wu, Hongwei; Hou, Shaocong; Peng, Ming; Yu, Xiao; Zou, Dechun

    2014-02-01

    One-dimensional semiconductor TiO2 nanowires (TNWs) have received widespread attention from solar cell and related optoelectronics scientists. The controllable synthesis of ordered TNW arrays on arbitrary substrates would benefit both fundamental research and practical applications. Herein, vertically aligned TNW arrays in situ grown on carbon fiber (CF) substrates through a facile, controllable, and seed-assisted thermal process is presented. Also, hierarchical TiO2 -nanoparticle/TNW arrays were prepared that favor both the dye loading and depressed charge recombination of the CF/TNW photoanode. An impressive conversion efficiency of 2.48 % (under air mass 1.5 global illumination) and an apparent efficiency of 4.18 % (with a diffuse board) due to the 3D light harvesting of the wire solar cell were achieved. Moreover, efficient and inexpensive wire solar cells made from all-CF electrodes and completely flexible CF-based wire solar cells were demonstrated, taking into account actual application requirements. This work may provide an intriguing avenue for the pursuit of lightweight, cost-effective, and high-performance flexible/wearable solar cells.

  18. Exploring highly porous Co2P nanowire arrays for electrochemical energy storage

    Science.gov (United States)

    Chen, Minghua; Zhou, Weiwei; Qi, Meili; Yin, Jinghua; Xia, Xinhui; Chen, Qingguo

    2017-02-01

    Controllable synthesis of mesoporous conductive metal phosphide nanowire arrays is critical for developing highly-active electrodes of alkaline batteries. Herein we develop a simple combined strategy for rational synthesis of mesoporous Co2P nanowire arrays by hydrothermal-phosphorization method. Free-standing mesoporous Co2P nanowires consisting of interconnected nanoparticles of 10-20 nm grow vertically to the substrate forming arrays. High electrical conductivity and large porosity are obtained in the arrays architecture. When characterized as the cathode of high-rate alkaline batteries, the designed Co2P nanowire arrays are proven with good electrochemical performance with a large capacity (133 mAh g-1 at 1 A g-1), stable cycling life with a capacity retention of almost 100% after 5000 cycles at 10 A g-1 owing to the mesoporous nanowire structure with short ion/electron transport path. Our synthetic approach can be useful for construction of other porous metal phosphide arrays for energy storage and conversion.

  19. Silicon on-chip bandpass filters for the multiplexing of high sensitivity photonic crystal microcavity biosensors

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Hai, E-mail: hai.yan@utexas.edu; Zou, Yi; Yang, Chun-Ju [Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin, 10100 Burnet Rd., Austin, Texas 78758 (United States); Chakravarty, Swapnajit, E-mail: swapnajit.chakravarty@omegaoptics.com [Omega Optics, Inc., 8500 Shoal Creek Blvd., Austin, Texas 78757 (United States); Wang, Zheng [Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin, 10100 Burnet Rd., Austin, Texas 78758 (United States); Materials Science and Engineering Program, Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712 (United States); Tang, Naimei; Chen, Ray T., E-mail: raychen@uts.cc.utexas.edu [Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin, 10100 Burnet Rd., Austin, Texas 78758 (United States); Omega Optics, Inc., 8500 Shoal Creek Blvd., Austin, Texas 78757 (United States); Fan, Donglei [Materials Science and Engineering Program, Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712 (United States); Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States)

    2015-03-23

    A method for the dense integration of high sensitivity photonic crystal (PC) waveguide based biosensors is proposed and experimentally demonstrated on a silicon platform. By connecting an additional PC waveguide filter to a PC microcavity sensor in series, a transmission passband is created, containing the resonances of the PC microcavity for sensing purpose. With proper engineering of the passband, multiple high sensitivity PC microcavity sensors can be integrated into microarrays and be interrogated simultaneously between a single input and a single output port. The concept was demonstrated with a 2-channel L55 PC biosensor array containing PC waveguide filters. The experiment showed that the sensors on both channels can be monitored simultaneously from a single output spectrum. Less than 3 dB extra loss for the additional PC waveguide filter is observed.

  20. Flexible and Semitransparent Organolead Triiodide Perovskite Network Photodetector Arrays with High Stability.

    Science.gov (United States)

    Deng, Hui; Yang, Xiaokun; Dong, Dongdong; Li, Bing; Yang, Dun; Yuan, Shengjie; Qiao, Keke; Cheng, Yi-Bing; Tang, Jiang; Song, Haisheng

    2015-12-09

    Organolead triiodide perovskite (CH3NH3PbI3) as a light-sensitive material has attracted extensive attention in optoelectronics. The reported perovskite photodetectors (PDs) mainly focus on the individual, which limits their spatial imaging applications. Uniform perovskite networks combining transparency and device performance were synthesized on poly(ethylene terephthalate) (PET) by controlling perovskite crystallization. Photodetector arrays based on above network were fabricated to demonstrate the potential for image mapping. The trade-off between the PD performance and transparency was systematically investigated and the optimal device was obtained from 30 wt % precursor concentration. The switching ratio, normalized detectivity, and equivalent dark current derived shot noise as the critical parameters of PD arrays reached 300, 1.02 × 10(12) Jones, and 4.73 × 10(-15)A Hz(-1/2), respectively. Furthermore, the PD arrays could clearly detect spatial light intensity distribution, thus demonstrating its preliminary imaging function. The perovskite network PD arrays fabricated on PET substrates could also conduct superior flexibility under wide angle and large number of bending. For the common problem of perovskite optoelectronics in stability, the perovskite networks sheathed with hydrophobic polymers greatly enhanced the device stability due to the improved interface contacts, surface passivation, and moisture isolation. Taking into consideration transparency, flexibility, imaging and stability, the present PD arrays were expected to be widely applied in visualized portable optoelectronic system.

  1. High sensitivity, wide coverage, and high-resolution NIR non-cryogenic spectrograph, WINERED

    Science.gov (United States)

    Ikeda, Yuji; Kobayashi, Naoto; Kondo, Sohei; Otsubo, Shogo; Hamano, Satoshi; Sameshima, Hiroaki; Yoshikawa, Tomoshiro; Fukue, Kei; Nakanishi, Kenshi; Kawanishi, Takafumi; Nakaoka, Tetsuya; Kinoshita, Masaomi; Kitano, Ayaka; Asano, Akira; Takenaka, Keiichi; Watase, Ayaka; Mito, Hiroyuki; Yasui, Chikako; Minami, Atsushi; Izumu, Natsuko; Yamamoto, Ryo; Mizumoto, Misaki; Arasaki, Takayuki; Arai, Akira; Matsunaga, Noriyuki; Kawakita, Hideyo

    2016-08-01

    Near-infrared (NIR) high-resolution spectroscopy is a fundamental observational method in astronomy. It provides significant information on the kinematics, the magnetic fields, and the chemical abundances, of astronomical objects embedded in or behind the highly extinctive clouds or at the cosmological distances. Scientific requirements have accelerated the development of the technology required for NIR high resolution spectrographs using 10 m telescopes. WINERED is a near-infrared (NIR) high-resolution spectrograph that is currently mounted on the 1.3 m Araki telescope of the Koyama Astronomical Observatory in Kyoto-Sangyo University, Japan, and has been successfully operated for three years. It covers a wide wavelength range from 0.90 to 1.35 μm (the z-, Y-, and J-bands) with a spectral resolution of R = 28,000 (Wide-mode) and R = 80,000 (Hires-Y and Hires-J modes). WINERED has three distinctive features: (i) optics with no cold stop, (ii) wide spectral coverage, and (iii) high sensitivity. The first feature, originating from the Joyce proposal, was first achieved by WINERED, with a short cutoff infrared array, cold baffles, and custom-made thermal blocking filters, and resulted in reducing the time for development, alignment, and maintenance, as well as the total cost. The second feature is realized with the spectral coverage of Δλ/λ 1/6 in a single exposure. This wide coverage is realized by a combination of a decent optical design with a cross-dispersed echelle and a large format array (2k x 2k HAWAII- 2RG). The Third feature, high sensitivity, is achieved via the high-throughput optics (>60 %) and the very low noise of the system. The major factors affecting the high throughput are the echelle grating and the VPH cross-disperser with high diffraction efficiencies of 83 % and 86 %, respectively, and the high QE of HAWAII-2RG (83 % at 1.23 μm). The readout noise of the electronics and the ambient thermal background radiation at longer wavelengths could be

  2. High yield, single droplet electrode arrays for nanoscale printed electronics.

    Science.gov (United States)

    Caironi, Mario; Gili, Enrico; Sakanoue, Tomo; Cheng, Xiaoyang; Sirringhaus, Henning

    2010-03-23

    In this work we demonstrate two building blocks of a scalable manufacturing technology for nanoscale electronic devices based on direct-write printing: an architecture for high-yield printing of electrode gaps with 100 nm dimension and a low-temperature silver complex ink for integration of organic materials with high conductivity metal interconnects. We use single printed droplets that are made to dewet slowly from each other to allow reliable, high yield patterning even in the presence of certain surface defects.

  3. Wide bandwidth and high resolution planar filter array based on DBR-metasurface-DBR structures

    CERN Document Server

    Horie, Yu; Arbabi, Ehsan; Kamali, Seyedeh Mahsa; Faraon, Andrei

    2016-01-01

    We propose and experimentally demonstrate a planar array of optical bandpass filters composed of low loss dielectric metasurface layers sandwiched between two distributed Bragg reflectors (DBRs). The two DBRs form a Fabry-P\\'erot resonator whose center wavelength is controlled by the design of the transmissive metasurface layer which functions as a phase shifting element. We demonstrate an array of bandpass filters with spatially varying center wavelengths covering a wide range of operation wavelengths of 250 nm around {\\lambda} = 1550 nm ({\\Delta}{\\lambda}/{\\lambda} = 16%). The center wavelengths of each filter are independently controlled only by changing the in-plane geometry of the sandwiched metasurfaces, and the experimentally measured quality factors are larger than 700. The demonstrated filter array can be directly integrated on top of photodetector arrays to realize on-chip high-resolution spectrometers with free-space coupling.

  4. Highly efficient ultrathin-film amorphous silicon solar cells on top of imprinted periodic nanodot arrays

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Wensheng, E-mail: yws118@gmail.com; Gu, Min, E-mail: mgu@swin.edu.au [Centre for Micro-Photonics, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Victoria 3122 (Australia); Tao, Zhikuo [College of Electronic Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023 (China); Ong, Thiam Min Brian [Plasma Sources and Application Center, NIE, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616 (Singapore); Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602 (Singapore)

    2015-03-02

    The addressing of the light absorption and conversion efficiency is critical to the ultrathin-film hydrogenated amorphous silicon (a-Si:H) solar cells. We systematically investigate ultrathin a-Si:H solar cells with a 100 nm absorber on top of imprinted hexagonal nanodot arrays. Experimental evidences are demonstrated for not only notable silver nanodot arrays but also lower-cost ITO and Al:ZnO nanodot arrays. The measured external quantum efficiency is explained by the simulation results. The J{sub sc} values are 12.1, 13.0, and 14.3 mA/cm{sup 2} and efficiencies are 6.6%, 7.5%, and 8.3% for ITO, Al:ZnO, and silver nanodot arrays, respectively. Simulated optical absorption distribution shows high light trapping within amorphous silicon layer.

  5. High speed vision processor with reconfigurable processing element array based on full-custom distributed memory

    Science.gov (United States)

    Chen, Zhe; Yang, Jie; Shi, Cong; Qin, Qi; Liu, Liyuan; Wu, Nanjian

    2016-04-01

    In this paper, a hybrid vision processor based on a compact full-custom distributed memory for near-sensor high-speed image processing is proposed. The proposed processor consists of a reconfigurable processing element (PE) array, a row processor (RP) array, and a dual-core microprocessor. The PE array includes two-dimensional processing elements with a compact full-custom distributed memory. It supports real-time reconfiguration between the PE array and the self-organized map (SOM) neural network. The vision processor is fabricated using a 0.18 µm CMOS technology. The circuit area of the distributed memory is reduced markedly into 1/3 of that of the conventional memory so that the circuit area of the vision processor is reduced by 44.2%. Experimental results demonstrate that the proposed design achieves correct functions.

  6. CdS and PbS nanoparticles co-sensitized TiO2 nanotube arrays and their enhanced photoelectrochemical property

    Science.gov (United States)

    Zhu, Yanmei; Wang, Renliang; Zhang, Wenping; Ge, Haiyan; Li, Li

    2014-10-01

    TiO2 nanotube arrays co-sensitized with CdS and PbS nanoparticles (TiO2 NTs/CdS/PbS) were successfully fabricated by a two-step process of anodization followed by successive ionic layer adsorption and reaction (SILAR) technique. The CdS and PbS nanoparticles grew uniformly on the walls of the TiO2 nanotubes in sequence, and the surface morphology, structure and photoelectrochemical performance of TiO2 NTs/CdS/PbS were investigated and discussed. The results show that the co-sensitization results in an increase in the visible light adsorption, photocurrent density, and photocatalytic and photoelectrocatalytic activity toward degradation of Rhodamine B (RhB). The corresponding mechanism of the TiO2 NTs/CdS/PbS for improving the photoelectrochemical property is tentatively proposed. Co-sensitization of TiO2 NTs by two semiconductors will be an effective way for the development of other high-performance energy-providing materials.

  7. Dark matter substructure modelling and sensitivity of the Cherenkov Telescope Array to Galactic dark halos

    CERN Document Server

    Hütten, Moritz; Maier, Gernot; Maurin, David

    2016-01-01

    Hierarchical structure formation leads to a clumpy distribution of dark matter in the Milky Way. These clumps are possible targets to search for dark matter annihilation with present and future $\\gamma$-ray instruments. Many uncertainties exist on the clump distribution, leading to disputed conclusions about the expected number of detectable clumps and the ensuing limits that can be obtained from non-detection. In this paper, we use the $\\tt{CLUMPY}$ code to simulate thousands of skymaps for several clump distributions. This allows us to statistically assess the typical properties (mass, distance, angular size, luminosity) of the detectable clumps. Varying parameters of the clump distributions allows us to identify the key quantities to which the number of detectable clumps is the most sensitive. Focusing our analysis on two extreme clump configurations, yet consistent with results from numerical simulations, we revisit and compare various calculations made for the $\\textit{Fermi}$-LAT instrument, in terms of...

  8. Monitoring wild animal communities with arrays of motion sensitive camera traps

    CERN Document Server

    Kays, Roland; Kranstauber, Bart; Jansen, Patrick A; Carbone, Chris; Rowcliffe, Marcus J; Fountain, Tony; Eggert, Jay; He, Zhihai

    2010-01-01

    Studying animal movement and distribution is of critical importance to addressing environmental challenges including invasive species, infectious diseases, climate and land-use change. Motion sensitive camera traps offer a visual sensor to record the presence of a broad range of species providing location -specific information on movement and behavior. Modern digital camera traps that record video present new analytical opportunities, but also new data management challenges. This paper describes our experience with a terrestrial animal monitoring system at Barro Colorado Island, Panama. Our camera network captured the spatio-temporal dynamics of terrestrial bird and mammal activity at the site - data relevant to immediate science questions, and long-term conservation issues. We believe that the experience gained and lessons learned during our year long deployment and testing of the camera traps as well as the developed solutions are applicable to broader sensor network applications and are valuable for the ad...

  9. Study on Millimeter-Wave Vivaldi Rectenna and Arrays with High Conversion Efficiency

    Directory of Open Access Journals (Sweden)

    Guan-Nan Tan

    2016-01-01

    Full Text Available A novel Vivaldi rectenna operated at 35 GHz with high millimeter wave to direct current (MMW-to-DC conversion efficiency is presented and the arrays are investigated. The measured conversion efficiency is 51.6% at 35 GHz and the efficiency higher than 30% is from 33.2 GHz to 36.6 GHz when the input MMW power is 79.4 mW. The receiving Vivaldi antenna loaded with metamaterial units has a high gain of 10.4 dBi at 35 GHz. A SIW- (substrate integrated waveguide- to-microstrip transition is designed not only to integrate the antenna with the rectifying circuit directly but also to provide the DC bypass for the rectifying circuit. When the power density is 8.7 mW/cm2, the received MMW power of the antenna is 5.6 mW, and the maximum conversion efficiency of the rectenna element is 31.5%. The output DC voltage of the element is nearly the same as that of the parallel array and is about half of the series array. The DC power obtained by the 1 × 2 rectenna arrays is about two times as much as that of the element. The conversion efficiencies of the arrays are very close to that of the element. Large scale arrays could be expended for collecting more DC power.

  10. Gene array and real time PCR analysis of the adrenal sensitivity to adrenocorticotropic hormone in pig

    Directory of Open Access Journals (Sweden)

    SanCristobal Magali

    2008-02-01

    Full Text Available Abstract Background Variability in hypothalamic-pituitary-adrenal (HPA axis activity has been shown to be influenced by genetic factors and related to great metabolic differences such as obesity. The aim of this study was to investigate molecular bases of genetic variability of the adrenal sensitivity to ACTH, a major source of variability, in Meishan (MS and Large White (LW pigs, MS being reported to exhibit higher basal cortisol levels, response to ACTH and fatness than LW. A pig cDNA microarray was used to identify changes in gene expression in basal conditions and in response to ACTH stimulation. Results Genotype and/or ACTH affected the expression of 211 genes related to transcription, cell growth/maintenance, signal transduction, cell structure/adhesion/extra cellular matrix and protein kinase/phosphatase activity. No change in the expression of known key regulator proteins of the ACTH signaling pathway or of steroidogenic enzymes was found. However, Mdh2, Sdha, Suclg2, genes involved in the tricarboxylic acid (TCA pathway, were over-expressed in MS pigs. Higher TCA cycle activity in MS than in LW may thus result in higher steroidogenic activity and thus explain the typically higher cortisol levels in MS compared to LW. Moreover, up-regulation of Star and Ldlr genes in MS and/or in response to ACTH suggest that differences in the adrenal function between MS and LW may also involve mechanisms requisite for cholesterol supply to steroidogenesis. Conclusion The present study provides new potential candidate genes to explain genetic variations in the adrenal sensitivity to ACTH and better understand relationship between HPA axis activity and obesity.

  11. Transplantation in highly HLA-sensitized patients: challenges and solutions

    Directory of Open Access Journals (Sweden)

    Kim IK

    2014-09-01

    Full Text Available Irene K Kim, Ashley Vo, Stanley C Jordan Transplant Immunotherapy Program, Comprehensive Transplant Center, Cedars-Sinai Medical Center, Los Angeles, CA, USA Abstract: Despite better understanding of the impact of development of the human leukocyte antigen (HLA antibody and numerous advancements in immunosuppressive therapy, the ability to successfully transplant highly sensitized patients remains a significant challenge. As the percentage of the waiting list becomes increasingly populated with highly sensitized patients, there is a growing demand for effective strategies to manage these patients. Over the past 20 years, desensitization therapies have been modified and developed, and are mainly utilized at transplant centers that have developed expertise. In addition, recognition that the highly sensitized patient population is disadvantaged on the transplant waiting list has led to recent changes in national kidney allocation policy. Furthermore, creative strategies, such as enrollment of sensitized patients into paired kidney exchange programs, have been developed to find compatible matches for these patients. The goal of this article is to address some of the specific challenges related to transplanting the highly sensitized patient at a high-volume transplant center with experience in desensitization and to review established and emerging solutions to help this patient population. Keywords: human leukocyte antigen, antibodies, desensitization, high-dose intravenous immunoglobulin, rituximab

  12. High power diode laser array development using completely indium free packaging technology with narrow spectrum

    Science.gov (United States)

    Hou, Dong; Wang, Jingwei; Gao, Lijun; Liang, Xuejie; Li, Xiaoning; Liu, Xingsheng

    2016-03-01

    The high power diode lasers have been widely used in many fields. In this work, a sophisticated high power and high performance horizontal array of diode laser stacks have been developed and fabricated with high duty cycle using hard solder bonding technology. CTE-matched submount and Gold Tin (AuSn) hard solder are used for bonding the diode laser bar to achieve the performances of anti-thermal fatigue, higher reliability and longer lifetime. This array consists of 30 bars with the expected optical output peak power of 6000W. By means of numerical simulation and analytical results, the diode laser bars are aligned on suitable positions along the water cooled cooler in order to achieve the uniform wavelength with narrow spectrum and accurate central wavelength. The performance of the horizontal array, such as output power, spectrum, thermal resistance, life time, etc., is characterized and analyzed.

  13. Electrochemical genosensor array for the simultaneous detection of multiple high-risk human papillomavirus sequences in clinical samples

    Energy Technology Data Exchange (ETDEWEB)

    Civit, Laia [Nanobiotechnology and Bioanalysis Group, Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, 43007 Tarragona (Spain); Fragoso, Alex, E-mail: alex.fragoso@urv.cat [Nanobiotechnology and Bioanalysis Group, Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, 43007 Tarragona (Spain); Hoelters, Sebastian; Duerst, Matthias [Department for Gynecology, Jena University Hospital, Friedrich-Schiller-University Jena, D-07743 Jena (Germany); O' Sullivan, Ciara K., E-mail: ciara.osullivan@urv.cat [Nanobiotechnology and Bioanalysis Group, Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, 43007 Tarragona (Spain); Institucio Catalana de Recerca i Estudis Avancats, Passeig Lluis Companys 23, 08010 Barcelona (Spain)

    2012-02-17

    Highlights: Black-Right-Pointing-Pointer High-risk human papillomavirus is detected in virtually all-invasive cervical cancers. Black-Right-Pointing-Pointer Electrochemical genosensor for simultaneous detection of multiple high-risk HPV applied to cervical scrape samples. Black-Right-Pointing-Pointer Excellent correlation with HPV genotyping carried out within a hospital laboratory. - Abstract: An electrochemical genosensor array for the simultaneous detection of three high-risk human papillomavirus (HPV) DNA sequences, HPV16, 18 and 45, exhibiting high sensitivity and selectivity is presented. The electrodes of a 4 Multiplication-Sign 4 array were modified via co-immobilization of a 1:100 (mol/mol) mixture of a thiolated probe and an oligoethyleneglycol-terminated bipodal thiol. Detection of synthetic and PCR products was carried out in a sandwich type format, with the target hybridized between a surface immobilized probe and a horseradish peroxidase-labelled secondary reporter probe. The detection limits obtained in the detection of each individual target were in the pM range, allowing the application of this sensor for the detection of samples obtained from PCR amplification of cervical scrape samples. The results obtained exhibited an excellent correlation with the HPV genotyping carried out within a hospital laboratory. Multiplexing and cross-reactivity studies demonstrated high selectivity over potential interfering sequences, facilitating application of the developed platform for the high-throughput screening of multiple high-risk DNA sequences.

  14. Mutagen sensitivity has high heritability: evidence from a twin study.

    Science.gov (United States)

    Wu, Xifeng; Spitz, Margaret R; Amos, Christopher I; Lin, Jie; Shao, Lina; Gu, Jian; de Andrade, Mariza; Benowitz, Neal L; Shields, Peter G; Swan, Gary E

    2006-06-15

    Despite numerous studies showing that mutagen sensitivity is a cancer predisposition factor, the heritability of mutagen sensitivity has not been clearly established. In this report, we used a classic twin study design to examine the role of genetic and environmental factors on the mutagen sensitivity phenotype. Mutagen sensitivity was measured in peripheral blood lymphocytes from 460 individuals [148 pairs of monozygotic (MZ) twins, 57 pairs of dizygotic (DZ) twins, and 50 siblings]. The intraclass correlation coefficients were all significantly higher in MZ twins than in dizygotes (DZ pairs and MZ-sibling pairs combined) for sensitivity to four different mutagen challenges. Applying biometric genetic modeling, we calculated a genetic heritability of 40.7%, 48.0%, 62.5%, and 58.8% for bleomycin, benzo[a]pyrene diol epoxide, gamma-radiation, and 4-nitroquinoline-1-oxide sensitivity, respectively. This study provides the strongest and most direct evidence that mutagen sensitivity is highly heritable, thereby validating the use of mutagen sensitivity as a cancer susceptibility factor.

  15. Patterning pallet arrays for cell selection based on high-resolution measurements of fluorescent biosensors.

    Science.gov (United States)

    Shadpour, Hamed; Zawistowski, Jon S; Herman, Annadele; Hahn, Klaus; Allbritton, Nancy L

    2011-06-24

    Pallet arrays enable cells to be separated while they remain adherent to a surface and provide a much greater range of cell selection criteria relative to that of current technologies. However there remains a need to further broaden cell selection criteria to include dynamic intracellular signaling events. To demonstrate the feasibility of measuring cellular protein behavior on the arrays using high resolution microscopy, the surfaces of individual pallets were modified to minimize the impact of scattered light at the pallet edges. The surfaces of the three-dimensional pallets on an array were patterned with a coating such as fibronectin using a customized stamping tool. Micropatterns of varying shape and size were printed in designated regions on the pallets in single or multiple steps to demonstrate the reliability and precision of patterning molecules on the pallet surface. Use of a fibronectin matrix stamped at the center of each pallet permitted the localization of H1299 and mouse embryonic fibroblast (MEF) cells to the pallet centers and away from the edges. Compared to pallet arrays with fibronectin coating the entire top surface, arrays with a central fibronectin pattern increased the percentage of cells localized to the pallet center by 3-4-fold. Localization of cells to the pallet center also enabled the physical separation of cells from optical artifacts created by the rough pallet side walls. To demonstrate the measurement of dynamic intracellular signaling on the arrays, fluorescence measurements of high spatial resolution were performed using a RhoA GTPase biosensor. This biosensor utilized fluorescence resonance energy transfer (FRET) between cyan fluorescent protein (CFP) and yellow fluorescent protein (YFP) to measure localized RhoA activity in cellular ruffles at the cell periphery. These results demonstrated the ability to perform spatially resolved measurements of fluorescence-based sensors on the pallet arrays. Thus, the patterned pallet arrays

  16. Photoelectrolchemical performance of PbS/CdS quantum dots co-sensitized TiO{sub 2} nanosheets array film photoelectrodes

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Huizhen; Li, Xue; Liu, Li; Niu, Jiasheng; Ding, Dong [National Key Lab of Superhard Materials, Jilin University, Changchun 130012 (China); Mu, Yannan [National Key Lab of Superhard Materials, Jilin University, Changchun 130012 (China); Department of Physics and Chemistry, Heihe University, Heihe 164300 (China); Su, Pengyu; Wang, Guangxia; Fu, Wuyou [National Key Lab of Superhard Materials, Jilin University, Changchun 130012 (China); Yang, Haibin, E-mail: yanghb@jlu.edu.cn [National Key Lab of Superhard Materials, Jilin University, Changchun 130012 (China)

    2015-10-25

    Herein, PbS/CdS quantum dots (QDs) co-sensitized titanium dioxide nanosheets array (TiO{sub 2}NSs) films were reported for the first time. The TiO{sub 2}NSs films exposed {001} facets were vertically grown on transparent conductive fluorine-doped tin oxide (FTO) glass substrates by a facile hydrothermal method. The PbS/CdS QDs were assembled on TiO{sub 2}NSs photoelectrode by successive ionic layer adsorption and reaction (SILAR). The X-ray diffraction pattern (XRD) and transmission electron microscopy (TEM) verified that QDs with a diameter less than 20 nm were uniformly anchored on the surface of the TiO{sub 2}NSs films. The QDs co-sensitization can significantly extend the absorption range and increase the absorption property of the photoelectrode by UV–vis absorption spectra. The optimal photoelectrolchemical (PEC) performance of PbS/CdS QDs co-sensitization TiO{sub 2}NSs was with photocurrent density of 6.12 mA cm{sup −2} under an illumination of AM 1.5 G, indicating the TiO{sub 2}NSs films co-sensitized by PbS/CdS QDs have potential applications in solar cells. - Highlights: • TiO{sub 2} nanosheets films were fabricated by a simple hydrothermal. • TiO{sub 2} nanosheets film exposed high energy facets was with gaps. • PbS/CdS co-sensitized TiO{sub 2} nanosheets film was obtained for the first time. • Photocurrent intensity of the novel photoelectrode increased to 6.12 mA cm{sup −2}.

  17. Arrays of Ultrathin CdS Nanoflakes with High-Energy Surface for Efficient Gas Detection.

    Science.gov (United States)

    Liu, Xiao-Hua; Yin, Peng-Fei; Kulinich, Sergei A; Zhou, Yu-Zhu; Mao, Jing; Ling, Tao; Du, Xi-Wen

    2017-01-11

    It is fascinating and challenging to endow conventional materials with unprecedented properties. For instance, cadmium sulfide (CdS) is an important semiconductor with excellent light response; however, its potential in gas-sensing was underestimated owing to relatively low chemical activity and poor electrical conductivity. Herein, we demonstrate that an ideal architecture, ultrathin nanoflake arrays (NFAs), can improve significantly gas-sensing properties of CdS material. The CdS NFAs are grown directly on the interdigitated electrode to expose large surface area. Their thickness is reduced below the double Debye length of CdS, permitting to achieve a full depletion of carriers. Particularly, the prepared CdS nanoflakes are enclosed with high-energy {0001} facets exposed, which provides more active sites for gas adsorption. Moreover, the NFAs exhibit the light-trapping effect, which further enhances their gas sensitivity. As a result, the as-prepared CdS NFAs demonstrate excellent gas-sensing and light-response properties, thus being capable of dual gas and light detection.

  18. Highly sensitive and selective sugar detection by terahertz nano-antennas

    Science.gov (United States)

    Lee, Dong-Kyu; Kang, Ji-Hun; Lee, Jun-Seok; Kim, Hyo-Seok; Kim, Chulki; Hun Kim, Jae; Lee, Taikjin; Son, Joo-Hiuk; Park, Q.-Han; Seo, Minah

    2015-10-01

    Molecular recognition and discrimination of carbohydrates are important because carbohydrates perform essential roles in most living organisms for energy metabolism and cell-to-cell communication. Nevertheless, it is difficult to identify or distinguish various carbohydrate molecules owing to the lack of a significant distinction in the physical or chemical characteristics. Although there has been considerable effort to develop a sensing platform for individual carbohydrates selectively using chemical receptors or an ensemble array, their detection and discrimination limits have been as high in the millimolar concentration range. Here we show a highly sensitive and selective detection method for the discrimination of carbohydrate molecules using nano-slot-antenna array-based sensing chips which operate in the terahertz (THz) frequency range (0.5-2.5 THz). This THz metamaterial sensing tool recognizes various types of carbohydrate molecules over a wide range of molecular concentrations. Strongly localized and enhanced terahertz transmission by nano-antennas can effectively increase the molecular absorption cross sections, thereby enabling the detection of these molecules even at low concentrations. We verified the performance of nano-antenna sensing chip by both THz spectra and images of transmittance. Screening and identification of various carbohydrates can be applied to test even real market beverages with a high sensitivity and selectivity.

  19. Highly sensitive and selective sugar detection by terahertz nano-antennas.

    Science.gov (United States)

    Lee, Dong-Kyu; Kang, Ji-Hun; Lee, Jun-Seok; Kim, Hyo-Seok; Kim, Chulki; Kim, Jae Hun; Lee, Taikjin; Son, Joo-Hiuk; Park, Q-Han; Seo, Minah

    2015-10-23

    Molecular recognition and discrimination of carbohydrates are important because carbohydrates perform essential roles in most living organisms for energy metabolism and cell-to-cell communication. Nevertheless, it is difficult to identify or distinguish various carbohydrate molecules owing to the lack of a significant distinction in the physical or chemical characteristics. Although there has been considerable effort to develop a sensing platform for individual carbohydrates selectively using chemical receptors or an ensemble array, their detection and discrimination limits have been as high in the millimolar concentration range. Here we show a highly sensitive and selective detection method for the discrimination of carbohydrate molecules using nano-slot-antenna array-based sensing chips which operate in the terahertz (THz) frequency range (0.5-2.5 THz). This THz metamaterial sensing tool recognizes various types of carbohydrate molecules over a wide range of molecular concentrations. Strongly localized and enhanced terahertz transmission by nano-antennas can effectively increase the molecular absorption cross sections, thereby enabling the detection of these molecules even at low concentrations. We verified the performance of nano-antenna sensing chip by both THz spectra and images of transmittance. Screening and identification of various carbohydrates can be applied to test even real market beverages with a high sensitivity and selectivity.

  20. Modular Ultra-High Power Solar Array Architecture Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Deployable Space Systems (DSS) will focus the proposed Phase 2 SBIR program on the hardware-based development and TRL advance of a highly-modularized and...

  1. High Count Rate Single Photon Counting Detector Array Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An optical communications receiver requires efficient and high-rate photon-counting capability so that the information from every photon, received at the aperture,...

  2. Microfabricated ion trap array

    Science.gov (United States)

    Blain, Matthew G.; Fleming, James G.

    2006-12-26

    A microfabricated ion trap array, comprising a plurality of ion traps having an inner radius of order one micron, can be fabricated using surface micromachining techniques and materials known to the integrated circuits manufacturing and microelectromechanical systems industries. Micromachining methods enable batch fabrication, reduced manufacturing costs, dimensional and positional precision, and monolithic integration of massive arrays of ion traps with microscale ion generation and detection devices. Massive arraying enables the microscale ion traps to retain the resolution, sensitivity, and mass range advantages necessary for high chemical selectivity. The reduced electrode voltage enables integration of the microfabricated ion trap array with on-chip circuit-based rf operation and detection electronics (i.e., cell phone electronics). Therefore, the full performance advantages of the microfabricated ion trap array can be realized in truly field portable, handheld microanalysis systems.

  3. CuInS2 quantum dot-sensitized TiO2 nanorod array photoelectrodes: synthesis and performance optimization.

    Science.gov (United States)

    Zhou, Zhengji; Yuan, Shengjie; Fan, Junqi; Hou, Zeliang; Zhou, Wenhui; Du, Zuliang; Wu, Sixin

    2012-11-27

    CuInS2 quantum dots (QDs) were deposited onto TiO2 nanorod arrays for different cycles by using successive ionic layer adsorption and reaction (SILAR) method. The effect of SILAR cycles on the light absorption and photoelectrochemical properties of the sensitized photoelectrodes was studied. With optimization of CuInS2 SILAR cycles and introduction of In2S3 buffer layer, quantum dot-sensitized solar cells assembled with 3-μm thick TiO2 nanorod film exhibited a short-circuit current density (Isc) of 4.51 mA cm-2, an open-circuit voltage (Voc) of 0.56 V, a fill factor (FF) of 0.41, and a power conversion efficiency (η) of 1.06%, respectively. This study indicates that SILAR process is a very promising strategy for preparing directly anchored semiconductor QDs on TiO2 nanorod surface in a straightforward but controllable way without any complicated fabrication procedures and introduction of a linker molecule.

  4. Synthesis and photoelectrochemical response of CdS quantum dot-sensitized TiO2 nanorod array photoelectrodes

    Science.gov (United States)

    Hu, Yunxia; Wang, Baoyuan; Zhang, Jieqiong; Wang, Tian; Liu, Rong; Zhang, Jun; Wang, Xina; Wang, Hao

    2013-05-01

    A continuous and compact CdS quantum dot-sensitive layer was synthesized on TiO2 nanorods by successive ionic layer adsorption and reaction (SILAR) and subsequent thermal annealing. The thickness of the CdS quantum dot layer was tuned by SILAR cycles, which was found to be closely related to light absorption and carrier transformation. The CdS quantum dot-sensitized TiO2 nanorod array photoelectrodes were characterized by scanning electron microscopy, X-ray diffraction, ultraviolet-visible absorption spectroscopy, and photoelectrochemical property measurement. The optimum sample was fabricated by SILAR in 70 cycles and then annealed at 400°C for 1 h in air atmosphere. A TiO2/CdS core-shell structure was formed with a diameter of 35 nm, which presented an improvement in light harvesting. Finally, a saturated photocurrent of 3.6 mA/cm2 was produced under the irradiation of AM1.5G simulated sunlight at 100 mW/cm2. In particular, the saturated current density maintained a fixed value of approximately 3 mA/cm2 without decadence as time passed under the light conditions, indicating the steady photoelectronic property of the photoanode.

  5. Achieving sensitive, high-resolution laser spectroscopy at CRIS

    Energy Technology Data Exchange (ETDEWEB)

    Groote, R. P. de [Instituut voor Kern- en Stralingsfysica, KU Leuven (Belgium); Lynch, K. M., E-mail: kara.marie.lynch@cern.ch [EP Department, CERN, ISOLDE (Switzerland); Wilkins, S. G. [The University of Manchester, School of Physics and Astronomy (United Kingdom); Collaboration: the CRIS collaboration

    2017-11-15

    The Collinear Resonance Ionization Spectroscopy (CRIS) experiment, located at the ISOLDE facility, has recently performed high-resolution laser spectroscopy, with linewidths down to 20 MHz. In this article, we present the modifications to the beam line and the newly-installed laser systems that have made sensitive, high-resolution measurements possible. Highlights of recent experimental campaigns are presented.

  6. A highly sensitive optical detector for use in deep underwater.

    Science.gov (United States)

    Hanada, H.; Hayashino, T.; Ito, M.; Iwasaki, A.; Kawamorita, K.; Kawamoto, H.; Matsumoto, T.; Narita, S.; Takayama, T.; Tanaka, S.; Yamaguchi, A.; Aoki, T.; Mitsui, K.; Ohashi, Y.; Okada, A.; Fukawa, M.; Uehara, S.; Bolesta, J. W.; Gorham, P. W.; Kondo, S.; Learned, J. G.; Matsuno, S.; Mignard, M.; Mitiguy, R.; O'Connor, D. J.; Peterson, V. Z.; Roberts, A.; Rosen, M.; Stenger, V. J.; Takemori, D.; Wilkins, G.; Grieder, P. K. F.; Minkowski, P.; Kitamura, T.; Camerini, U.; Grogan, W.; Jaworski, M.; March, R.; Narita, T.; Nicklaus, D.

    1998-05-01

    The authors have developed an optical detector module for use in deep underwater experiments that will search for high-energy neutrinos from cosmic rays and astronomical sources. This module is sensitive to single photons, is operable under high pressure, functions automatically and is remotely controlled.

  7. Implementation of digital multiplexing for high resolution X-ray detector arrays.

    Science.gov (United States)

    Sharma, P; Swetadri Vasan, S N; Titus, A H; Cartwright, A N; Bednarek, D R; Rudin, S

    2012-01-01

    We describe and demonstrate for the first time the use of the novel Multiple Module Multiplexer (MMMIC) for a 2×2 array of new electron multiplying charge coupled device (EMCCD) based x-ray detectors. It is highly desirable for x-ray imaging systems to have larger fields of view (FOV) extensible in two directions yet to still be capable of doing high resolution imaging over regions-of-interest (ROI). The MMMIC achieves these goals by acquiring and multiplexing data from an array of imaging modules thereby enabling a larger FOV, and at the same time allowing high resolution ROI imaging through selection of a subset of modules in the array. MMMIC also supports different binning modes. This paper describes how a specific two stage configuration connecting three identical MMMICs is used to acquire and multiplex data from a 2×2 array of EMCCD based detectors. The first stage contains two MMMICs wherein each MMMIC is getting data from two EMCCD detectors. The multiplexed data from these MMMICs is then forwarded to the second stage MMMIC in the similar fashion. The second stage that has only one MMMIC gives the final 12 bit multiplexed data from four modules. This data is then sent over a high speed Camera Link interface to the image processing computer. X-ray images taken through the 2×2 array of EMCCD based detectors using this two stage configuration of MMMICs are shown successfully demonstrating the concept.

  8. Nanocoax Arrays for Sensing Devices

    Science.gov (United States)

    Rizal, Binod

    We have adapted a nanocoax array architecture for high sensitivity, all-electronic, chemical and biological sensing. Arrays of nanocoaxes with various dielectric annuli were developed using polymer replicas of Si nanopillars made via soft lithography. These arrays were implemented in the development of two different kinds of chemical detectors. First, arrays of nanocoaxes constructed with different porosity dielectric annuli were employed to make capacitive detectors for gaseous molecules and to investigate the role of dielectric porosity in the sensitivity of the device. Second, arrays of nanocoaxes with partially hollowed annuli were used to fabricate three-dimensional electrochemical biosensors within which we studied the role of nanoscale gap between electrodes on device sensitivity. In addition, we have employed a molecular imprint technique to develop a non-conducting molecularly imprinted polymer thin film of thickness comparable to size of biomolecules as an "artificial antibody" architecture for the detection of biomolecules.

  9. A cute and highly contrast-sensitive superposition eye : The diurnal owlfly Libelloides macaronius

    NARCIS (Netherlands)

    Belušič, Gregor; Pirih, Primož; Stavenga, Doekele G.

    The owlfly Libelloides macaronius (Insecta: Neuroptera) has large bipartite eyes of the superposition type. The spatial resolution and sensitivity of the photoreceptor array in the dorsofrontal eye part was studied with optical and electrophysiological methods. Using structured illumination

  10. A cute and highly contrast-sensitive superposition eye - the diurnal owlfly Libelloides macaronius

    NARCIS (Netherlands)

    Belusic, Gregor; Pirih, Primoz; Stavenga, Doekele G.; Belušič, Gregor; Pirih, Primož

    2013-01-01

    The owlfly Libelloides macaronius (Insecta: Neuroptera) has large bipartite eyes of the superposition type. The spatial resolution and sensitivity of the photoreceptor array in the dorsofrontal eye part was studied with optical and electrophysiological methods. Using structured illumination microsco

  11. Fabrication of nanopore and nanoparticle arrays with high aspect ratio AAO masks

    Science.gov (United States)

    Li, Z. P.; Xu, Z. M.; Qu, X. P.; Wang, S. B.; Peng, J.; Mei, L. H.

    2017-03-01

    How to use high aspect ratio anodic aluminum oxide (AAO) membranes as an etching and evaporation mask is one of the unsolved problems in the application of nanostructured arrays. Here we describe the versatile utilizations of the highly ordered AAO membranes with a high aspect ratio of more than 20 used as universal masks for the formation of various nanostructure arrays on various substrates. The result shows that the fabricated nanopore and nanoparticle arrays of substrates inherit the regularity of the AAO membranes completely. The flat AAO substrates and uneven AAO frontages were attached to the Si substrates respectively as an etching mask, which demonstrates that the two kinds of replication, positive and negative, represent the replication of the mirroring of Si substrates relative to the flat AAO substrates and uneven AAO frontages. Our work is a breakthrough for the broad research field of surface nano-masking.

  12. Multi-channel microstrip transceiver arrays using harmonics for high field MR imaging in humans.

    Science.gov (United States)

    Wu, Bing; Wang, Chunsheng; Lu, Jonathan; Pang, Yong; Nelson, Sarah J; Vigneron, Daniel B; Zhang, Xiaoliang

    2012-02-01

    Radio-frequency (RF) transceiver array design using primary and higher order harmonics for in vivo parallel magnetic resonance imaging imaging (MRI) and spectroscopic imaging is proposed. The improved electromagnetic decoupling performance, unique magnetic field distributions and high-frequency operation capabilities of higher-order harmonics of resonators would benefit transceiver arrays for parallel MRI, especially for ultrahigh field parallel MRI. To demonstrate this technique, microstrip transceiver arrays using first and second harmonic resonators were developed for human head parallel imaging at 7T. Phantom and human head images were acquired and evaluated using the GRAPPA reconstruction algorithm. The higher-order harmonic transceiver array design technique was also assessed numerically using FDTD simulation. Compared with regular primary-resonance transceiver designs, the proposed higher-order harmonic technique provided an improved g-factor and increased decoupling among resonant elements without using dedicated decoupling circuits, which would potentially lead to a better parallel imaging performance and ultimately faster and higher quality imaging. The proposed technique is particularly suitable for densely spaced transceiver array design where the increased mutual inductance among the elements becomes problematic. In addition, it also provides a simple approach to readily upgrade the channels of a conventional primary resonator microstrip array to a larger number for faster imaging.

  13. Fabrication of high-aspect ratio SU-8 micropillar arrays

    DEFF Research Database (Denmark)

    Amato, Letizia; Keller, Stephan S.; Heiskanen, Arto

    2012-01-01

    SU-8 is the preferred photoresist for development and fabrication of high aspect ratio (HAR) three dimensional patterns. However, processing of SU-8 is a challenging task, especially when the film thickness as well as the aspect ratio is increasing and the size of the features is close to the res...

  14. Hydrothermal Etching Treatment to Rutile TiO2 Nanorod Arrays for Improving the Efficiency of CdS-Sensitized TiO2 Solar Cells.

    Science.gov (United States)

    Wan, Jingshu; Liu, Rong; Tong, Yuzhu; Chen, Shuhuang; Hu, Yunxia; Wang, Baoyuan; Xu, Yang; Wang, Hao

    2016-12-01

    Highly ordered TiO2 nanorod arrays (NRAs) were directly grown on an F:SnO2 (FTO) substrate without any seed layer by hydrothermal route. For a larger surface area, the second-step hydrothermal treatment in hydrochloric acid was carried out to the as-prepared TiO2 NRAs. The results showed that the center portion of the TiO2 nanorods were dissolved in the etching solution to form a nanocave at the initial etching process. As the etching time extended, the tip parts of the nanocave wall split into lots of nanowires with a reduced diameter, giving rise to a remarkable increase of specific surface area for the TiO2 NRAs. The TiO2 films after etching treatment were sensitized by CdS quantum dots (QDs) to fabricate quantum dot-sensitized solar cells (QDSSCs), which exhibited a significant improvement in the photocurrent density in comparison with that of the un-treated device, this mainly attributed to the enhancement of QD loading and diffused reflectance ability. Through modifying the etching TiO2 films with TiCl4, a relatively high power conversion efficiency (PCE) of 3.14 % was obtained after optimizing the etching time.

  15. High-resolution images of tremor migrations beneath the Olympic Peninsula from stacked array of arrays seismic data

    Science.gov (United States)

    Peng, Yajun; Rubin, Allan M.

    2016-02-01

    Episodic tremor and slip (ETS) in subduction zones is generally interpreted as the manifestation of shear slip near the base of earthquake-generating portion of the plate interface. Here we devise a new method of cross-correlating stacked Array of Arrays seismic data that provides greatly improved tremor locations, a proxy for the underlying slow slip, beneath the Olympic Peninsula. This increased resolution allows us to image many features of tremor that were not visible previously. We resolve the spatial transition between the rupture zones of the inter-ETS and major ETS episodes in 2010, suggesting stress redistribution by the former. Most tremor migrations propagated along the slowly advancing main tremor front during both the inter-ETS and the major ETS episodes, even though the main front of the former deviated strongly from its usual (along-dip) orientation. We find a distinct contrast between along-dip rupture extent of large-scale rapid tremor reversals (RTRs) to the south and that to the north in our study region that anticorrelates with the locations of inter-ETS events. These RTRs originate from the main front, similar to smaller-scale RTRs previously observed at high-resolution, and many start by propagating along the main front. This could be consistent with RTRs being triggered by a cascading failure of brittle asperities. After initiation, the RTRs repeatedly occupy the same source region, and the early repetitions appear not to be tidally driven. Their stress drop may come from continuing fault weakening processes within the tremor zone, or loading by aseismic slip in surrounding regions.

  16. Two-dimensional DOA Estimation with High Accuracy for MIMO Radar Using Cross Array

    Directory of Open Access Journals (Sweden)

    Liang Hao

    2016-06-01

    Full Text Available In this study, we investigate the estimation of the Two-Dimensional (2D Direction Of Arrival (DOA in monostatic multiple-input–multiple-output radar with cross array and propose a novel, highly accurate DOA estimation method based on unitary transformation. First, we design a new unitary matrix using the central symmetry of a cross array at transmit and receive sites. Then, the rotational invariance relationships of these arrays with long and short baselines can be transformed into a real-value field via unitary transformation. In addition, non-ambiguous and highly accurate 2D DOA estimations can be obtained using a unitary dual-resolution ESPRIT algorithm. Simulations show that the proposed method can estimate 2D highly accurate spatial angles using automatic pairing without incurring the expense of array aperture and peak searching. Compared with traditional unitary transformation, the steering vectors of transmit and receive arrays can be transformed into real-value fields via the unitary matrix and the transformation method of our scheme, respectively. This effectively overcomes the problem of shift invariance factors in real-value fields that cannot be extracted using traditional algorithms. Therefore, the proposed method can absolutely compute eigenvalue decomposition and estimate parameters in a real-value field, resulting in lower computational complexity compared with traditional methods. Simulation results verify both the correctness of our theoretical analysis and the effectiveness of the proposed algorithm.

  17. Micromachined high frequency PMN-PT/epoxy 1-3 composite ultrasonic annular array.

    Science.gov (United States)

    Liu, Changgeng; Djuth, Frank; Li, Xiang; Chen, Ruimin; Zhou, Qifa; Shung, K Kirk

    2012-04-01

    This paper reports the design, fabrication, and performance of miniature micromachined high frequency PMN-PT/epoxy 1-3 composite ultrasonic annular arrays. The PMN-PT single crystal 1-3 composites were made with micromachining techniques. The area of a single crystal pillar was 9×9 μm. The width of the kerf among pillars was ∼5 μm and the kerfs were filled with a polymer. The composite thickness was 25 μm. A six-element annular transducer of equal element area of 0.2 mm(2) with 16 μm kerf widths between annuli was produced. The aperture size the array transducer is about 1.5 mm in diameter. A novel electrical interconnection strategy for high density array elements was implemented. After the transducer was attached to the electric connection board and packaged, the array transducer was tested in a pulse/echo arrangement, whereby the center frequency, bandwidth, two-way insertion loss (IL), and cross talk between adjacent elements were measured for each annulus. The center frequency was 50 MHz and -6 dB bandwidth was 90%. The average insertion loss was 19.5 dB at 50 MHz and the crosstalk between adjacent elements was about -35 dB. The micromachining techniques described in this paper are promising for the fabrication of other types of high frequency transducers, e.g. 1D and 2D arrays.

  18. Facile preparation of titanium dioxide nano-capsule arrays used as photo-anode for dye sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Su, Penglei; Li, Hongyi, E-mail: lhy06@bjut.edu.cn; Wang, Jinshu, E-mail: wangjsh@bjut.edu.cn; Wu, Junshu; Zhao, Bingxin; Wang, Fei

    2015-08-30

    Graphical abstract: - Highlights: • TiO{sub 2} nanoparticles have been introduced into TiO{sub 2} nanotube using a facile liquid phase deposition method at low temperature in atmosphere. • Dye solar cells have been assembled on flexible titanium substrate. • The incident photo-electron conversion efficiency has been improved 76% compared with pure TiO{sub 2} nanotube arrays. - Abstract: To improve titanium dioxide (TiO{sub 2}) nanotube arrays’ performance on dye sensitized solar cells (DSSCs), TiO{sub 2} nano-capsule arrays (TNCP) have been designed and prepared by planting TiO{sub 2} nanoparticles into TiO{sub 2} nanotube (TNT) using a facile liquid phase deposition (LPD) route which does not require any special equipment and both improve the specific surface area and surface energy of TNT at low temperature. It has been found that TiO{sub 2} nanoparticles are homogeneously distributed along the wall of TNT and their crystal size is calculated to be 5–10 nm. The obtained TNCP's specific surface area and surface energy have been increased from 27.1 (for pure TNT) to 33.4 m{sup 2}/g and from 67.7 (for pure TNT) to 76.4 mJ/m{sup 2}, respectively. When used as photo-anodes of DSSCs, TNCP shows higher energy conversion efficiency, which is 1.7 times that of pure TNT. Therefore, the present work provides one effective strategy to better TNT's performance on DSSCs, which can be assembled on metal substrate in large scale.

  19. Porous ZnO nanosheet arrays constructed on weaved metal wire for flexible dye-sensitized solar cells.

    Science.gov (United States)

    Dai, Hui; Zhou, Yong; Chen, Liang; Guo, Binglei; Li, Aidong; Liu, Jianguo; Yu, Tao; Zou, Zhigang

    2013-06-07

    Porous zinc oxide (ZnO) nanosheet (NS) arrays constructed by connected nanocrystallites were built on weaved metal wire (WMW) via hydrothermal treatment followed by calcination, and used as photoanodes for flexible dye-sensitized solar cells (DSSCs). An overall light-to-electricity conversion efficiency (η) of 2.70% was achieved for the DSSC under 100 mW cm(-2) illumination, and this η was found to be much higher than that of the DSSC with ZnO nanowire (NW) as the photoanode (0.71%). The far superior performance of the DSSC with ZnO-NS is essentially attributed to: (i) the film consisting of nanosheets with interconnected nanocrystallites can allow relatively direct pathways for the transportation of electrons as the nanosheets have a regular structure with the sheets being oriented to the electrode; (ii) the nanocrystallites assembly and porous character of the nanosheets can provide a large surface area for dye adsorption, which is in favor of enhancing the light absorption and the light propagation; (iii) the nanopores embedded in the nanosheet can act as "branch lines" for more efficient electrolyte diffusion into the interstice of the densely packed nanosheets in the array. A further improvement in the efficiency of the DSSC with ZnO-NS was achieved through the atomic layer deposition (ALD) of an ultrathin titanium oxide (TiO2) layer onto the ZnO-NS layer. The larger charge transfer resistance along with the introduction of a TiO2 shell is thought to reduce the surface recombination and thus contribute to the increase in the open circuit voltage (Voc) of the DSCs and higher conversion efficiency (3.09%).

  20. High-dynamic-range coherent diffractive imaging: ptychography using the mixed-mode pixel array detector

    Energy Technology Data Exchange (ETDEWEB)

    Giewekemeyer, Klaus, E-mail: klaus.giewekemeyer@xfel.eu [European XFEL GmbH, Hamburg (Germany); Philipp, Hugh T. [Cornell University, Ithaca, NY (United States); Wilke, Robin N. [Georg-August-Universität Göttingen, Göttingen (Germany); Aquila, Andrew [European XFEL GmbH, Hamburg (Germany); Osterhoff, Markus [Georg-August-Universität Göttingen, Göttingen (Germany); Tate, Mark W.; Shanks, Katherine S. [Cornell University, Ithaca, NY (United States); Zozulya, Alexey V. [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Salditt, Tim [Georg-August-Universität Göttingen, Göttingen (Germany); Gruner, Sol M. [Cornell University, Ithaca, NY (United States); Cornell University, Ithaca, NY (United States); Kavli Institute of Cornell for Nanoscience, Ithaca, NY (United States); Mancuso, Adrian P. [European XFEL GmbH, Hamburg (Germany)

    2014-08-07

    The advantages of a novel wide dynamic range hard X-ray detector are demonstrated for (ptychographic) coherent X-ray diffractive imaging. Coherent (X-ray) diffractive imaging (CDI) is an increasingly popular form of X-ray microscopy, mainly due to its potential to produce high-resolution images and the lack of an objective lens between the sample and its corresponding imaging detector. One challenge, however, is that very high dynamic range diffraction data must be collected to produce both quantitative and high-resolution images. In this work, hard X-ray ptychographic coherent diffractive imaging has been performed at the P10 beamline of the PETRA III synchrotron to demonstrate the potential of a very wide dynamic range imaging X-ray detector (the Mixed-Mode Pixel Array Detector, or MM-PAD). The detector is capable of single photon detection, detecting fluxes exceeding 1 × 10{sup 8} 8-keV photons pixel{sup −1} s{sup −1}, and framing at 1 kHz. A ptychographic reconstruction was performed using a peak focal intensity on the order of 1 × 10{sup 10} photons µm{sup −2} s{sup −1} within an area of approximately 325 nm × 603 nm. This was done without need of a beam stop and with a very modest attenuation, while ‘still’ images of the empty beam far-field intensity were recorded without any attenuation. The treatment of the detector frames and CDI methodology for reconstruction of non-sensitive detector regions, partially also extending the active detector area, are described.

  1. High-Q cavity-induced synchronization in oscillator arrays

    DEFF Research Database (Denmark)

    Filatrella, Giovanni; Pedersen, Niels Falsig; Wiesenfeld, Kurt

    2000-01-01

    A model for a large number of Josephson junctions coupled to a cavity is presented. The system displays synchronization behavior very similar to that reported in recent experiments [P. Barbara ct al., Phys. Rev. Lett. 82, 1963 (1999)]. The essential dynamical mechanism responsible for coherence...... should be generic in nonlinear oscillator systems where the interactions are mediated by a highly resonant cavity, in analogy with gas lasers....

  2. Highly sensitive optical sensor system for blood leakage detection

    Science.gov (United States)

    Ueda, Masahiro; Ishikawa, Kazuhiko; Jie, Chen; Sanae, Mizuno; Touma, Yasunori

    A highly sensitive method for the detection of blood leakage has been developed, and a practical sensor system for blood concentration measurement has been constructed. The present method is based on the attenuation of laser light by blood cells. The effects of the fluctuations of the incident laser light power are eliminated by normalizing the attenuated light intensity by the incident light intensity. A part of the incident laser light is reflected by a beam splitter mounted at the entrance of the test cell, of which the power is measured to provide base data for normalization. The optical path is extended to enhance sensitivity by using a pair of side mirrors. This multi-reflection method is very effective to increase sensitivity; the maximum sensitivity obtained for blood concentration is about 4 X 10 -6 by volume, which is significantly higher than that of the conventional sensors.

  3. High efficiency,high power 808nm laser array and stacked arrays optimized for elevated temperature operation

    Institute of Scientific and Technical Information of China (English)

    Crump P A; Wise D; Crum T R; DeVito M; Farmer J; Grimshaw M; Huang Z; Igl S A; Macomber S; Thiagarajan P

    2004-01-01

    Operation of 808-nm laser diode pumping at elevated temperature is crucial to many applications. Reliable operation at high power is limited by high thermal load and low catastrophic optical mirror damage (COMD) threshold at elevated temperature range. We demonstrated high efficiency and high power operation at elevated temperature with high COMD power. These results were achieved through device design optimization such as growth conditions, doping profile, and materials composition of the quantum-well and other layers. Electrical-to-optical efficiency as high as 62% was obtained through lowered threshold current, lowered series resistance and increased slope efficiency. The performance of single broad-area laser diodes scales to that of high power single bars on water-cooled copper micro-channel heatsinks or conductively-cooled CS heatsinks. No reduction in bar performance or significant spectral broadening is seen when these micro-channel coolers are assembled into 6-bar and 18-bar CW stacks for the highest power levels.

  4. Investigation of high-resolution functional magnetic resonance imaging by means of surface and array radiofrequency coils at 7 T.

    Science.gov (United States)

    van der Zwaag, Wietske; Marques, José P; Hergt, Martin; Gruetter, Rolf

    2009-10-01

    In this investigation, high-resolution, 1x1x1-mm(3) functional magnetic resonance imaging (fMRI) at 7 T is performed using a multichannel array head coil and a surface coil approach. Scan geometry was optimized for each coil separately to exploit the strengths of both coils. Acquisitions with the surface coil focused on partial brain coverage, while whole-brain coverage fMRI experiments were performed with the array head coil. BOLD sensitivity in the occipital lobe was found to be higher with the surface coil than with the head array, suggesting that restriction of signal detection to the area of interest may be beneficial for localized activation studies. Performing independent component analysis (ICA) decomposition of the fMRI data, we consistently detected BOLD signal changes and resting state networks. In the surface coil data, a small negative BOLD response could be detected in these resting state network areas. Also in the data acquired with the surface coil, two distinct components of the positive BOLD signal were consistently observed. These two components were tentatively assigned to tissue and venous signal changes.

  5. Scalable photonic crystal chips for high sensitivity protein detection.

    Science.gov (United States)

    Liang, Feng; Clarke, Nigel; Patel, Parth; Loncar, Marko; Quan, Qimin

    2013-12-30

    Scalable microfabrication technology has enabled semiconductor and microelectronics industries, among other fields. Meanwhile, rapid and sensitive bio-molecule detection is increasingly important for drug discovery and biomedical diagnostics. In this work, we designed and demonstrated that photonic crystal sensor chips have high sensitivity for protein detection and can be mass-produced with scalable deep-UV lithography. We demonstrated label-free detection of carcinoembryonic antigen from pg/mL to μg/mL, with high quality factor photonic crystal nanobeam cavities.

  6. Experimental Investigation on a Highly Sensitive Atomic Magnetometer

    Institute of Scientific and Technical Information of China (English)

    LI Shu-Guang; XU Yun-Fei; WANG Zhao-Ying; LIU Yun-Xian; LIN Qiang

    2009-01-01

    A highly sensitive all-optical atomic magnetometer based on the magnetooptical effect which uses the advanced technique of single laser beam detection is reported and demonstrated experimentally.A sensitivityof 0.5 pT/Hz1/2 is obtained by analyzing the magnetic noise spectrum,which exceeds that of most traditional magnetometers.This kind of atomic magnetometer is very compact,has a low power consumption,and has a high theoretical sensitivity limit,which make it suitable for many applications.

  7. A nanofiber based artificial electronic skin with high pressure sensitivity and 3D conformability

    Science.gov (United States)

    Zhong, Weibin; Liu, Qiongzhen; Wu, Yongzhi; Wang, Yuedan; Qing, Xing; Li, Mufang; Liu, Ke; Wang, Wenwen; Wang, Dong

    2016-06-01

    Pressure sensors with 3D conformability are highly desirable components for artificial electronic skin or e-textiles that can mimic natural skin, especially for application in real-time monitoring of human physiological signals. Here, a nanofiber based electronic skin with ultra-high pressure sensitivity and 3D conformability is designed and built by interlocking two elastic patterned nanofibrous membranes. The patterned membrane is facilely prepared by casting conductive nanofiber ink into a silicon mould to form an array of semi-spheroid-like protuberances. The protuberances composed of intertwined elastic POE nanofibers and PPy@PVA-co-PE nanofibers afford a tunable effective elastic modulus that is capable of capturing varied strains and stresses, thereby contributing to a high sensitivity for pressure sensing. This electronic skin-like sensor demonstrates an ultra-high sensitivity (1.24 kPa-1) below 150 Pa with a detection limit as low as about 1.3 Pa. The pixelated sensor array and a RGB-LED light are then assembled into a circuit and show a feasibility for visual detection of spatial pressure. Furthermore, a nanofiber based proof-of-concept wireless pressure sensor with a bluetooth module as a signal transmitter is proposed and has demonstrated great promise for wireless monitoring of human physiological signals, indicating a potential for large scale wearable electronic devices or e-skin.Pressure sensors with 3D conformability are highly desirable components for artificial electronic skin or e-textiles that can mimic natural skin, especially for application in real-time monitoring of human physiological signals. Here, a nanofiber based electronic skin with ultra-high pressure sensitivity and 3D conformability is designed and built by interlocking two elastic patterned nanofibrous membranes. The patterned membrane is facilely prepared by casting conductive nanofiber ink into a silicon mould to form an array of semi-spheroid-like protuberances. The

  8. Highly uniform hole spacing micro brushes based on aligned carbon nanotube arrays

    Science.gov (United States)

    Yang, Zhi; Zhu, Xingzhong; Huang, Xiaolu; Cheng, Yingwu; Liu, Yun; Geng, Huijuan; Wu, Yue; Su, Yanjie; Wei, Hao; Zhang, Yafei

    2013-11-01

    Highly uniform hole spacing micro brushes were fabricated based on aligned carbon nanotube (CNT) arrays synthesized by chemical vapor deposition method with the assistance of anodic aluminum oxide (AAO) template. Different micro brushes from CNT arrays were constructed on silicon, glass, and polyimide substrates, respectively. The micro brushes had highly uniform hole spacing originating from the regularly periodic pore structure of AAO template. The CNT arrays, serving as bristles, were firmly grafted on the substrates. The brushes can easily clean particles with scale of micrometer on the surface of silicon wafer and from the narrow spaces between the electrodes in a series of cleaning experiments. The results show the potential application of the CNT micro brushes as a cleaning tool in microelectronics manufacture field.

  9. Improvement on a 2 × 2 Elements High-Gain Circularly Polarized Antenna Array

    Directory of Open Access Journals (Sweden)

    C. Liu

    2015-01-01

    Full Text Available A novel antipodal Vivaldi antenna with tapering serrated structure at the edges is proposed. Compared with traditional Vivaldi antennas without serrated structure, the gain of the designed antenna is significantly improved in the desired frequency band (4.5–7.5 GHz. In addition, a 2 × 2 Vivaldi antenna array with an orthorhombic structure is designed and fabricated to achieve a circular polarization (CP characteristic. With this configuration, the 3 dB axial ratio bandwidth of the array reaches about 42% with respect to the center frequency of 6 GHz and a high gain is achieved as well. The novel Vivaldi antenna and CP antenna array both have ultrawide band (UWB and high-gain characteristics, which may be applied to the field of commercial communication, remote sensing, and so forth.

  10. Linearity Analysis on a Series-Split Capacitor Array for High-Speed SAR ADCs

    Directory of Open Access Journals (Sweden)

    Yan Zhu

    2010-01-01

    Full Text Available A novel Capacitor array structure for Successive Approximation Register (SAR ADC is proposed. This circuit efficiently utilizes charge recycling to achieve high-speed of operation and it can be applied to high-speed and low-to-medium-resolution SAR ADC. The parasitic effects and the static linearity performance, namely, the INL and DNL, of the proposed structure are theoretically analyzed and behavioral simulations are performed to demonstrate its effectiveness under those nonidealities. Simulation results show that to achieve the same conversion performance the proposed capacitor array structure can reduce the average power consumed from the reference ladder by 90% when compared to the binary-weighted splitting capacitor array structure.

  11. The characteristics of machined surface controlled by multi tip arrayed tool and high speed spindle.

    Science.gov (United States)

    Kim, Yong Woo; Choi, Soo Chang; Park, Jeong Woo; Lee, Deug Woo

    2010-07-01

    In this study, we propose one of the ultra-precision machining methods that can be adapted brittle material as well as soft material by using multi arrayed diamond tips and high speed spindle. Conventional machining method is too hard to control surface roughness and surface texture against brittle material because particles of grinding tools are irregular size and material can be fragile. Therefore we were able to design tool paths and machine controlled pattern on surface by multi arrayed diamond tips which has uniform size made in MEMS fabrication and high speed spindle of which maximum speed is about 300,000 rpm. We defined several parameters that can have effect on machining surface. Those are multi array of diamond tips (n * n), speed of the air spindle, and feeding rate. Surface roughness and surface texture can be controlled by those parameters for micro machining.

  12. Sensitivity encoded silicon photomultiplier--a new sensor for high-resolution PET-MRI.

    Science.gov (United States)

    Schulz, Volkmar; Berker, Yannick; Berneking, Arne; Omidvari, Negar; Kiessling, Fabian; Gola, Alberto; Piemonte, Claudio

    2013-07-21

    Detectors for simultaneous positron emission tomography and magnetic resonance imaging in particular with sub-mm spatial resolution are commonly composed of scintillator crystal arrays, readout via arrays of solid state sensors, such as avalanche photo diodes (APDs) or silicon photomultipliers (SiPMs). Usually a light guide between the crystals and the sensor is used to enable the identification of crystals which are smaller than the sensor elements. However, this complicates crystal identification at the gaps and edges of the sensor arrays. A solution is to use as many sensors as crystals with a direct coupling, which unfortunately increases the complexity and power consumption of the readout electronics. Since 1997, position-sensitive APDs have been successfully used to identify sub-mm crystals. Unfortunately, these devices show a limitation in their time resolution and a degradation of spatial resolution when placed in higher magnetic fields. To overcome these limitations, this paper presents a new sensor concept that extends conventional SiPMs by adding position information via the spatial encoding of the channel sensitivity. The concept allows a direct coupling of high-resolution crystal arrays to the sensor with a reduced amount of readout channels. The theory of sensitivity encoding is detailed and linked to compressed sensing to compute unique sparse solutions. Two devices have been designed using one- and two-dimensional linear sensitivity encoding with eight and four readout channels, respectively. Flood histograms of both devices show the capability to precisely identify all 4 × 4 LYSO crystals with dimensions of 0.93 × 0.93 × 10 mm(3). For these crystals, the energy and time resolution (MV ± SD) of the devices with one (two)-dimensional encoding have been measured to be 12.3 · (1 ± 0.047)% (13.7 · (1 ± 0.047)%) around 511 keV with a paired coincidence time resolution (full width at half maximum) of 462 · (1 ± 0.054) ps (452 · (1 ± 0

  13. Highly tunable ultra-narrow-resonances with optical nano-antenna phased arrays in the infrared

    CERN Document Server

    Li, Shi-Qiang; Guo, Peijun; Buchholz, D Bruce; Qiu, Ziwei; Ketterson, John B; Ocola, Leonidas E; Sakoda, Kazuaki; Chang, Robert P H

    2014-01-01

    We report our recent development in pursuing high Quality-Factor (high-Q factor) plasmonic resonances, with vertically aligned two dimensional (2-D) periodic nanorod arrays. The 2-D vertically aligned nano-antenna array can have high-Q resonances varying arbitrarily from near infrared to terahertz regime, as the antenna resonances of the nanorod are highly tunable through material properties, the length of the nanorod, and the orthogonal polarization direction with respect to the lattice surface,. The high-Q in combination with the small optical mode volume gives a very high Purcell factor, which could potentially be applied to various enhanced nonlinear photonics or optoelectronic devices. The 'hot spots' around the nanorods can be easily harvested as no index-matching is necessary. The resonances maintain their high-Q factor with the change of the environmental refractive index, which is of great interest for molecular sensing.

  14. Diffusion of dilute gas in arrays of randomly distributed, vertically aligned, high-aspect-ratio cylinders

    Science.gov (United States)

    Guerra, Carlos

    2017-01-01

    In this work we modelled the diffusive transport of a dilute gas along arrays of randomly distributed, vertically aligned nanocylinders (nanotubes or nanowires) as opposed to gas diffusion in long pores, which is described by the well-known Knudsen theory. Analytical expressions for (i) the gas diffusion coefficient inside such arrays, (ii) the time between collisions of molecules with the nanocylinder walls (mean time of flight), (iii) the surface impingement rate, and (iv) the Knudsen number of such a system were rigidly derived based on a random-walk model of a molecule that undergoes memoryless, diffusive reflections from nanocylinder walls assuming the molecular regime of gas transport. It can be specifically shown that the gas diffusion coefficient inside such arrays is inversely proportional to the areal density of cylinders and their mean diameter. An example calculation of a diffusion coefficient is delivered for a system of titanium isopropoxide molecules diffusing between vertically aligned carbon nanotubes. Our findings are important for the correct modelling and optimisation of gas-based deposition techniques, such as atomic layer deposition or chemical vapour deposition, frequently used for surface functionalisation of high-aspect-ratio nanocylinder arrays in solar cells and energy storage applications. Furthermore, gas sensing devices with high-aspect-ratio nanocylinder arrays and the growth of vertically aligned carbon nanotubes need the fundamental understanding and precise modelling of gas transport to optimise such processes. PMID:28144565

  15. Large pi-aromatic molecules as potential sensitizers for highly efficient dye-sensitized solar cells.

    Science.gov (United States)

    Imahori, Hiroshi; Umeyama, Tomokazu; Ito, Seigo

    2009-11-17

    Recently, dye-sensitized solar cells have attracted much attention relevant to global environmental issues. Thus far, ruthenium(II) bipyridyl complexes have proven to be the most efficient TiO(2) sensitizers in dye-sensitized solar cells. However, a gradual increment in the highest power conversion efficiency has been recognized in the past decade. More importantly, considering that ruthenium is a rare metal, novel dyes without metal or using inexpensive metal are desirable for highly efficient dye-sensitized solar cells. Large pi-aromatic molecules, such as porphyrins, phthalocyanines, and perylenes, are important classes of potential sensitizers for highly efficient dye-sensitized solar cells, owing to their photostability and high light-harvesting capabilities that can allow applications in thinner, low-cost dye-sensitized solar cells. Porphyrins possess an intense Soret band at 400 nm and moderate Q bands at 600 nm. Nevertheless, the poor light-harvesting properties relative to the ruthenium complexes have limited the cell performance of porphyrin-sensitized TiO(2) cells. Elongation of the pi conjugation and loss of symmetry in porphyrins cause broadening and a red shift of the absorption bands together with an increasing intensity of the Q bands relative to that of the Soret band. On the basis of the strategy, the cell performance of porphyrin-sensitized solar cells has been improved intensively by the enhanced light absorption. Actually, some push-pull-type porphyrins have disclosed a remarkably high power conversion efficiency (6-7%) that was close to that of the ruthenium complexes. Phthalocyanines exhibit strong absorption around 300 and 700 nm and redox features that are similar to porphyrins. Moreover, phthalocyanines are transparent over a large region of the visible spectrum, thereby enabling the possibility of using them as "photovoltaic windows". However, the cell performance was poor, owing to strong aggregation and lack of directionality in the

  16. Curved Microneedle Array-Based sEMG Electrode for Robust Long-Term Measurements and High Selectivity.

    Science.gov (United States)

    Kim, Minjae; Kim, Taewan; Kim, Dong Sung; Chung, Wan Kyun

    2015-07-06

    Surface electromyography is widely used in many fields to infer human intention. However, conventional electrodes are not appropriate for long-term measurements and are easily influenced by the environment, so the range of applications of sEMG is limited. In this paper, we propose a flexible band-integrated, curved microneedle array electrode for robust long-term measurements, high selectivity, and easy applicability. Signal quality, in terms of long-term usability and sensitivity to perspiration, was investigated. Its motion-discriminating performance was also evaluated. The results show that the proposed electrode is robust to perspiration and can maintain a high-quality measuring ability for over 8 h. The proposed electrode also has high selectivity for motion compared with a commercial wet electrode and dry electrode.

  17. Curved Microneedle Array-Based sEMG Electrode for Robust Long-Term Measurements and High Selectivity

    Directory of Open Access Journals (Sweden)

    Minjae Kim

    2015-07-01

    Full Text Available Surface electromyography is widely used in many fields to infer human intention. However, conventional electrodes are not appropriate for long-term measurements and are easily influenced by the environment, so the range of applications of sEMG is limited. In this paper, we propose a flexible band-integrated, curved microneedle array electrode for robust long-term measurements, high selectivity, and easy applicability. Signal quality, in terms of long-term usability and sensitivity to perspiration, was investigated. Its motion-discriminating performance was also evaluated. The results show that the proposed electrode is robust to perspiration and can maintain a high-quality measuring ability for over 8 h. The proposed electrode also has high selectivity for motion compared with a commercial wet electrode and dry electrode.

  18. Enhanced power conversion efficiency of CdS quantum dot sensitized solar cells with ZnO nanowire arrays as the photoanodes

    Science.gov (United States)

    Qi, Junjie; Liu, Wang; Biswas, Chandan; Zhang, Guangjie; Sun, Lifang; Wang, Zengze; Hu, Xiaofeng; Zhang, Yue

    2015-08-01

    We report the fabrication of CdS quantum dot sensitized solar cells with ZnO nanowire arrays as the photoanodes. The influences of precursor solution temperature and sensitizing cycles on the performance of CdS quantum dots sensitized ZnO nanowires solar cells were studied. Successive ionic layer adsorption and reaction (SILAR) method was applied to deposit CdS quantum dots on the surface of ZnO nanowire arrays for assembling ZnO/CdS electrodes. The results of scanning electron microscopic (SEM), X-ray diffraction (XRD) patterns and UV-vis absorption spectroscopy indicated that the ZnO nanowires electrodes were well-covered with CdS quantum dots. The temperature of the ethanol sensitizing solutions significantly influenced the performance of ZnO/CdS electrodes by affecting the rate of deposition reaction and the penetration ability of ethanol solution. The CdS quantum dots sensitized ZnO-based solar cells exhibited a short-circuit current density (Jsc) of 3.1 mA/cm2, an open-circuit voltage (Voc) of 0.55 V and a photovoltaic conversion efficiency of 0.72%, which is much higher than that reported in literatures, under the illumination of one sun (AM 1.5, 100 mW/cm2) when the temperature of the ethanol solutions was 60 °C and ZnO arrays were sensitized for seven times.

  19. Electrodeposition of hierarchical ZnO nanorod arrays on flexible stainless steel mesh for dye-sensitized solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Hui; Zhai, Xiangyang; Liu, Wenwu; Zhang, Mei; Guo, Min, E-mail: guomin@ustb.edu.cn

    2015-07-01

    Hierarchical ZnO nanorod arrays (ZNRAs) were synthesized on flexible stainless steel mesh (SSM) in large scale by a two-step facile electrodeposition method. The structure and morphology of the as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The growth mechanism of the ZnO hierarchical nanostructures was also discussed. Moreover, the effect of ZnO morphology on the photovoltaic performance of the flexible DSSCs based on SSM supported ZnO nanostructures was investigated in detail. It is shown that the flexible DSSCs exhibited a relatively higher power conversion efficiency of 1.11% compared with that based on primary ZNRAs. - Highlights: • Hierarchical ZnO nanorod arrays (ZNRAs) were prepared by electrodeposition method. • Flexible stainless steel mesh (SSM) supported with hierarchical ZNRAs was first used for DSSCs. • The effect of ZnO morphology on the photovoltaic performance of flexible DSSCs was investigated. • The DSSC based on 3-Hierarchical ZNRAs/ZNPs showed a relatively efficiency of 1.11%.

  20. Flexible, phase-matched, linear receive arrays for high-field MRI in monkeys.

    Science.gov (United States)

    Goense, Jozien; Logothetis, Nikos K; Merkle, Hellmut

    2010-10-01

    High signal-to-noise ratios (SNR) are essential for high-resolution anatomical and functional MRI. Phased arrays are advantageous for this but have the drawback that they often have inflexible and bulky configurations. Particularly in experiments where functional MRI is combined with simultaneous electrophysiology, space constraints can be prohibitive. To this end we developed a highly flexible multiple receive element phased array for use on anesthetized monkeys. The elements are interchangeable and different sizes and combinations of coil elements can be used, for instance, combinations of single and overlapped elements. The preamplifiers including control electronics are detachable and can serve a variety of prefabricated and phase matched arrays of different configurations, allowing the elements to always be placed in close proximity to the area of interest. Optimizing performance of the individual elements ensured high SNR at the cortical surface as well as in deeper laying structures. Performance of a variety of arrangements of gapped linear arrays was evaluated at 4.7 and 7T in high-resolution anatomical and functional MRI.

  1. Portable High Sensitivity and High Resolution Sensor to Determine Oxygen Purity Levels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this Phase I STTR project is to develop a highly sensitive oxygen (O2) sensor, with high accuracy and precision, to determine purity levels of high...

  2. New light-amplifier-based detector designs for high spatial resolution and high sensitivity CBCT mammography and fluoroscopy.

    Science.gov (United States)

    Rudin, Stephen; Kuhls, Andrew T; Yadava, Girijesh K; Josan, Gaurav C; Wu, Ye; Chityala, Ravishankar N; Rangwala, Hussain S; Ciprian Ionita, N; Hoffmann, Kenneth R; Bednarek, Daniel R

    2006-12-02

    New cone-beam computed tomographic (CBCT) mammography system designs are presented where the detectors provide high spatial resolution, high sensitivity, low noise, wide dynamic range, negligible lag and high frame rates similar to features required for high performance fluoroscopy detectors. The x-ray detectors consist of a phosphor coupled by a fiber-optic taper to either a high gain image light amplifier (LA) then CCD camera or to an electron multiplying CCD. When a square-array of such detectors is used, a field-of-view (FOV) to 20 × 20 cm can be obtained where the images have pixel-resolution of 100 µm or better. To achieve practical CBCT mammography scan-times, 30 fps may be acquired with quantum limited (noise free) performance below 0.2 µR detector exposure per frame. Because of the flexible voltage controlled gain of the LA's and EMCCDs, large detector dynamic range is also achievable. Features of such detector systems with arrays of either generation 2 (Gen 2) or 3 (Gen 3) LAs optically coupled to CCD cameras or arrays of EMCCDs coupled directly are compared. Quantum accounting analysis is done for a variety of such designs where either the lowest number of information carriers off the LA photo-cathode or electrons released in the EMCCDs per x-ray absorbed in the phosphor are large enough to imply no quantum sink for the design. These new LA- or EMCCD-based systems could lead to vastly improved CBCT mammography, ROI-CT, or fluoroscopy performance compared to systems using flat panels.

  3. Aluminum nano-cantilevers for high sensitivity mass sensors

    DEFF Research Database (Denmark)

    Davis, Zachary James; Boisen, Anja

    2005-01-01

    We have fabricated Al nano-cantilevers using a very simple one mask contact UV lithography technique with lateral dimensions under 500 nm and vertical dimensions of approximately 100 nm. These devices are demonstrated as highly sensitive mass sensors by measuring their dynamic properties. Further...

  4. Highly Sensitive AMS Measurement of 53Mn at CIAE

    Institute of Scientific and Technical Information of China (English)

    DONG; Ke-jun; HU; Hao; LIU; Guang-shan; HE; Ming; LI; Zhen-yu; DOU; Liang; XIE; Lin-bo; LIU; Jian-cheng; WANG; Xiang-gao; SHEN; Hong-tao; LIN; De-yu; ZHENG; Guo-wen; WANG; Xiao-bo; LI; Heng; LI; Chao-li; WU; Shao-yong; YOU; Qu-bo; JIN; Chun-sheng; CHEN; Zhi-gang; YUAN; Jian; JIANG; Shan

    2013-01-01

    Methods for highly sensitive AMS measurement of 53Mn were explored by extracting different Mn-containing molecular ions in ion source and using different chemical forms of sample materials.Preliminary results indicate that a method for AMS measurement of 53Mn has been established and a-155355

  5. Sensitivity Study of Strapdown Inertial Sensors in High Performance Applications

    Science.gov (United States)

    1980-12-01

    system error varied with a change in heading 7K. ( xii 1 SENSITIVITY STUDY OF STRAPDOWN INERTIAL SENSORS IN HIGH PERFORMANCE APPLICATIONS I. Introduction...given in Tabla 10. 23 State Meaning o Basic Altitude Damped INS x(1) Error in East Longitude 5.7735 x 1O Ŗ arc min x(2) Error in North Latitude

  6. [Burner head with high sensitivity in atomic absorption spectroscopy].

    Science.gov (United States)

    Feng, X; Yang, Y

    1998-12-01

    This paper presents a burner head with gas-sample separate entrance and double access, which is used for atomic absorption spectroscopy. According to comparison and detection, the device can improve sensitivity by a factor of 1 to 5. In the meantime it has properties of high stability and resistance to interference.

  7. Microelectromechanical Resonant Accelerometer Designed with a High Sensitivity

    Science.gov (United States)

    Zhang, Jing; Su, Yan; Shi, Qin; Qiu, An-Ping

    2015-01-01

    This paper describes the design and experimental evaluation of a silicon micro-machined resonant accelerometer (SMRA). This type of accelerometer works on the principle that a proof mass under acceleration applies force to two double-ended tuning fork (DETF) resonators, and the frequency output of two DETFs exhibits a differential shift. The dies of an SMRA are fabricated using silicon-on-insulator (SOI) processing and wafer-level vacuum packaging. This research aims to design a high-sensitivity SMRA because a high sensitivity allows for the acceleration signal to be easily demodulated by frequency counting techniques and decreases the noise level. This study applies the energy-consumed concept and the Nelder-Mead algorithm in the SMRA to address the design issues and further increase its sensitivity. Using this novel method, the sensitivity of the SMRA has been increased by 66.1%, which attributes to both the re-designed DETF and the reduced energy loss on the micro-lever. The results of both the closed-form and finite-element analyses are described and are in agreement with one another. A resonant frequency of approximately 22 kHz, a frequency sensitivity of over 250 Hz per g, a one-hour bias stability of 55 μg, a bias repeatability (1σ) of 48 μg and the bias-instability of 4.8 μg have been achieved. PMID:26633425

  8. Microelectromechanical Resonant Accelerometer Designed with a High Sensitivity

    Directory of Open Access Journals (Sweden)

    Jing Zhang

    2015-12-01

    Full Text Available This paper describes the design and experimental evaluation of a silicon micro-machined resonant accelerometer (SMRA. This type of accelerometer works on the principle that a proof mass under acceleration applies force to two double-ended tuning fork (DETF resonators, and the frequency output of two DETFs exhibits a differential shift. The dies of an SMRA are fabricated using silicon-on-insulator (SOI processing and wafer-level vacuum packaging. This research aims to design a high-sensitivity SMRA because a high sensitivity allows for the acceleration signal to be easily demodulated by frequency counting techniques and decreases the noise level. This study applies the energy-consumed concept and the Nelder-Mead algorithm in the SMRA to address the design issues and further increase its sensitivity. Using this novel method, the sensitivity of the SMRA has been increased by 66.1%, which attributes to both the re-designed DETF and the reduced energy loss on the micro-lever. The results of both the closed-form and finite-element analyses are described and are in agreement with one another. A resonant frequency of approximately 22 kHz, a frequency sensitivity of over 250 Hz per g, a one-hour bias stability of 55 μg, a bias repeatability (1σ of 48 μg and the bias-instability of 4.8 μg have been achieved.

  9. Highly uniform and vertically aligned SnO2 nanochannel arrays for photovoltaic applications

    Science.gov (United States)

    Kim, Jae-Yup; Kang, Jin Soo; Shin, Junyoung; Kim, Jin; Han, Seung-Joo; Park, Jongwoo; Min, Yo-Sep; Ko, Min Jae; Sung, Yung-Eun

    2015-04-01

    Nanostructured electrodes with vertical alignment have been considered ideal structures for electron transport and interfacial contact with redox electrolytes in photovoltaic devices. Here, we report large-scale vertically aligned SnO2 nanochannel arrays with uniform structures, without lateral cracks fabricated by a modified anodic oxidation process. In the modified process, ultrasonication is utilized to avoid formation of partial compact layers and lateral cracks in the SnO2 nanochannel arrays. Building on this breakthrough, we first demonstrate the photovoltaic application of these vertically aligned SnO2 nanochannel arrays. These vertically aligned arrays were directly and successfully applied in quasi-solid state dye-sensitized solar cells (DSSCs) as photoanodes, yielding reasonable conversion efficiency under back-side illumination. In addition, a significantly short process time (330 s) for achieving the optimal thickness (7.0 μm) and direct utilization of the anodized electrodes enable a simple, rapid and low-cost fabrication process. Furthermore, a TiO2 shell layer was coated on the SnO2 nanochannel arrays by the atomic layer deposition (ALD) process for enhancement of dye-loading and prolonging the electron lifetime in the DSSC. Owing to the presence of the ALD TiO2 layer, the short-circuit photocurrent density (Jsc) and conversion efficiency were increased by 20% and 19%, respectively, compared to those of the DSSC without the ALD TiO2 layer. This study provides valuable insight into the development of efficient SnO2-based photoanodes for photovoltaic application by a simple and rapid fabrication process.Nanostructured electrodes with vertical alignment have been considered ideal structures for electron transport and interfacial contact with redox electrolytes in photovoltaic devices. Here, we report large-scale vertically aligned SnO2 nanochannel arrays with uniform structures, without lateral cracks fabricated by a modified anodic oxidation process

  10. Morphological studies of vertical arrays TiO2 nanotubes by electrochemical anodization technique for dye sensitized solar cell application

    Science.gov (United States)

    Su'ait, M. S.; Alamgir, F.; Scardi, P.; Ahmad, A.

    2013-11-01

    A vertical array titanium dioxide nanotube (n-TiO2) for photovoltaic materials in dye sensitized solar cell has been synthesized by electrochemical anodization technique in NH4F aqueous solution. The morphological observation performed by SEM analysis on the scratch film showed that the distribution growths of TiO2 nanotubes on Ti subtract were uniform. The duration of growth is varied up to 12 h, with tubes length approximately 1 μm. However, at the maximum duration, a compact TiO2 layers were formed. This phenomenon is due to the field-assisted anodic oxidation at the interfaces of Ti/TiO2 is at equal rate with the field-assisted dissolution rate of the top TiO2 nanotube's surface, resulting from the decreased quantity of F- ions to form fluoro complexes, [TiF6]2-. A slight increase in the rate of the chemical dissolution reaction produced a precipitated TiO2. Hence, [TiF6]2- complexes which are required for tubes formation are difficult to exist.

  11. CoS acicular nanorod arrays for the counter electrode of an efficient dye-sensitized solar cell.

    Science.gov (United States)

    Kung, Chung-Wei; Chen, Hsin-Wei; Lin, Chia-Yu; Huang, Kuan-Chieh; Vittal, R; Ho, Kuo-Chuan

    2012-08-28

    One-dimensional cobalt sulfide (CoS) acicular nanorod arrays (ANRAs) were obtained on a fluorine-doped tin oxide (FTO) substrate by a two-step approach. First, Co(3)O(4) ANRAs were synthesized, and then they were converted to CoS ANRAs for various periods. The compositions of the films obtained after various conversion periods were verified by X-ray diffraction, UV-visible spectrophotometry, and X-ray photoelectron spectroscopy; their morphologies were examined at different periods by scanning electron microscopic and transmission electron microscopic images. Electrocatalytic abilities of the films toward I(-)/I(3)(-) were verified through cyclic voltammetry (CV) and Tafel polarization curves. Long-term stability of the films in I(-)/I(3)(-) electrolyte was studied by CV. The FTO substrates with CoS ANRAs were used as the counter electrodes for dye-sensitized solar cells; a maximum power conversion efficiency of 7.67% was achieved for a cell with CoS ANRAs, under 100 mW/cm(2), which is nearly the same as that of a cell with a sputtered Pt counter electrode (7.70%). Electrochemical impedance spectroscopy was used to substantiate the photovoltaic parameters.

  12. Highly sensitive detection using microring resonator and nanopores

    Science.gov (United States)

    Bougot-Robin, K.; Hoste, J. W.; Le Thomas, N.; Bienstman, P.; Edel, J. B.

    2016-04-01

    One of the most significant challenges facing physical and biological scientists is the accurate detection and identification of single molecules in free-solution environments. The ability to perform such sensitive and selective measurements opens new avenues for a large number of applications in biological, medical and chemical analysis, where small sample volumes and low analyte concentrations are the norm. Access to information at the single or few molecules scale is rendered possible by a fine combination of recent advances in technologies. We propose a novel detection method that combines highly sensitive label-free resonant sensing obtained with high-Q microcavities and position control in nanoscale pores (nanopores). In addition to be label-free and highly sensitive, our technique is immobilization free and does not rely on surface biochemistry to bind probes on a chip. This is a significant advantage, both in term of biology uncertainties and fewer biological preparation steps. Through combination of high-Q photonic structures with translocation through nanopore at the end of a pipette, or through a solid-state membrane, we believe significant advances can be achieved in the field of biosensing. Silicon microrings are highly advantageous in term of sensitivity, multiplexing, and microfabrication and are chosen for this study. In term of nanopores, we both consider nanopore at the end of a nanopipette, with the pore being approach from the pipette with nanoprecise mechanical control. Alternatively, solid state nanopores can be fabricated through a membrane, supporting the ring. Both configuration are discussed in this paper, in term of implementation and sensitivity.

  13. Fabrication of High-Frequency pMUT Arrays on Silicon Substrates

    DEFF Research Database (Denmark)

    Pedersen, Thomas; Zawada, Tomasz; Hansen, Karsten

    2010-01-01

    A novel technique based on silicon micromachining for fabrication of linear arrays of high-frequency piezoelectric micromachined ultrasound transducers (pMUT) is presented. Piezoelectric elements are formed by deposition of lead zirconia titanate into etched features of a silicon substrate...

  14. Multilevel kinoform microlens arrays in fused silica for high-power laser optics

    Science.gov (United States)

    Atuchin, Victor V.; Soldatenkov, I. S.; Kirpichnikov, A. V.; Mikhailov, E. V.; Pestryakov, Efim V.; Sheglov, Dmitriy V.

    2004-03-01

    Diffraction microlens arrays has been fabricated in silica substrates by deep UV photolithography and wet chemical etching. The calculated kinoform profile has been approximated by multistep function and this microrelief has been transfered into the surface with wet etching through the photoresist mask. The diffraction efficiency of eight-level kinoform microlens is as high as 85%.

  15. The nuclear spectroscopic telescope array (NuSTAR) high-energy X-ray mission

    DEFF Research Database (Denmark)

    Madsen, Kristin K.; Harrison, Fiona A.; Hongjun An

    2014-01-01

    The Nuclear Spectroscopic Telescope Array (NuSTAR) mission was launched on 2012 June 13 and is the first focusing high-energy X-ray telescope in orbit operating above ~10 keV. NuSTAR flies two co-aligned Wolter-I conical approximation X-ray optics, coated with Pt/C and W/Si multilayers...

  16. GOSSIPO-4: an array of high resolution TDCs with a PLL control

    NARCIS (Netherlands)

    Zappon, F.; van Beuzekom, M.; Gromov, V.; Kluit, R.; Fang, X.; Kruth, A.

    2012-01-01

    GOSSIPO-4 is a prototype chip featuring an array of high resolution Time to Digital Converters with a PLL control that has been taped out the 9th of August 2011. This prototype is the successor of GOSSIPO-3 test chip and the precursor of the 65k pixel chip TimePix3. The prototype is being developed

  17. Reverse Phase Protein Arrays for High-Throughput Protein Measurements in Mammospheres

    DEFF Research Database (Denmark)

    Pedersen, Marlene Lemvig; Block, Ines; List, Markus

    Protein Array (RPPA)-based readout format integrated into robotic siRNA screening. This technique would allow post-screening high-throughput quantification of protein changes. Recently, breast cancer stem cells (BCSCs) have attracted much attention, as a tumor- and metastasis-driving subpopulation...

  18. Integrated Automation of High-Throughput Screening and Reverse Phase Protein Array Sample Preparation

    DEFF Research Database (Denmark)

    Pedersen, Marlene Lemvig; Block, Ines; List, Markus

    multiplexing readouts, but this has a natural limitation. High-content screening via image acquisition and analysis allows multiplexing of few parameters, but is connected to substantial time consumption and complex logistics. We report on integration of Reverse Phase Protein Arrays (RPPA)-based readouts...

  19. Dense high-aspect ratio 3D carbon pillars on interdigitated microelectrode arrays

    DEFF Research Database (Denmark)

    Amato, Letizia; Heiskanen, Arto; Hansen, Rasmus

    2015-01-01

    In this work we present high-aspect ratio carbon pillars (1.4 μm in diameter and ∼11 μm in height) on top of interdigitated electrode arrays to be used for electrochemical applications. For this purpose, different types of 2D and 3D pyrolysed carbon structures were fabricated and characterised...

  20. High field matching effects in superconducting Nb porous arrays catalyzed from anodic alumina templates

    DEFF Research Database (Denmark)

    Vinckx, W.; Vanacken, J.; Moshchalkov, V.V.;

    2007-01-01

    Vortex pinning in a superconducting Nb thin film deposited on an anodically grown alumina template is investigated. Anodic oxidation of aluminium layers permits under specific conditions the formation of highly ordered porous alumina, a membrane-like structure consisting of triangular arrays...... of parallel pores. Its pore diameter and interpore distance are set by careful tuning of the anodization parameters. A superconducting Nb thin film is deposited directly onto the alumina film. The porous alumina acts as a template and it allows Nb to form a periodic pinning array during its growth. Pinning...

  1. A novel technique for electronic phasing of high power fiber amplifier arrays

    Science.gov (United States)

    Shay, T. M.; Baker, J. T.; Sanchez, Anthony D.; Robin, C. A.; Vergien, C. L.; Zeringue, C.; Gallant, D.; Lu, Chunte A.; Pulford, Benjamin; Bronder, T. J.; Lucero, Arthur

    2009-06-01

    We report high power phase locked fiber amplifier array using the Self-Synchronous Locking of Optical Coherence by Single-detector Electronic-frequency Tagging technique. We report the first experimental results for a five element amplifier array with a total locked power of more than 725-W. We will report on experimental measurements of the phase fluctuations versus time when the control loop is closed. The rms phase error was measured to be λ/60. Recent results will be reported. To the best of the authors' knowledge this is the highest fiber laser power to be coherently combined.

  2. A High-Efficiency Si Nanowire Array/Perovskite Hybrid Solar Cell

    OpenAIRE

    Yan, Xin; Zhang, Chen; Wang, Jiamin; Zhang, Xia; Ren, Xiaomin

    2017-01-01

    A low-cost Si nanowire array/perovskite hybrid solar cell is proposed and simulated. The solar cell consists of a Si p-i-n nanowire array filled with CH3NH3PbI3, in which both the nanowires and perovskite absorb the incident light while the nanowires act as the channels for transporting photo-generated electrons and holes. The hybrid structure has a high absorption efficiency in a broad wavelength range of 300~800 nm. A large short-circuit current density of 28.8 mA/cm2 and remarkable convers...

  3. The High-Level Interface Definitions in the ASTRI/CTA Mini Array Software System (MASS)

    Science.gov (United States)

    Conforti, V.; Tosti, G.; Schwarz, J.; Bruno, P.; Cefal‘A, M.; Paola, A. D.; Gianotti, F.; Grillo, A.; Russo, F.; Tanci, C.; Testa, V.; Antonelli, L. A.; Canestrari, R.; Catalano, O.; Fiorini, M.; Gallozzi, S.; Giro, E.; Palombara, N. L.; Leto, G.; Maccarone, M. C.; Pareschi, G.; Stringhetti, L.; Trifoglio, M.; Vercellone, S.; Astri Collaboration; Cta Consortium

    2015-09-01

    ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) is a Flagship Project funded by the Italian Ministry of Education, University and Research, and led by INAF, the Italian National Institute of Astrophysics. Within this framework, INAF is currently developing an end-to-end prototype, named ASTRI SST-2M, of a Small Size Dual-Mirror Telescope for the Cherenkov Telescope Array, CTA. A second goal of the project is the realization of the ASTRI/CTA mini-array, which will be composed of seven SST-2M telescopes placed at the CTA Southern Site. The ASTRI Mini Array Software System (MASS) is designed to support the ASTRI/CTA mini-array operations. MASS is being built on top of the ALMA Common Software (ACS) framework, which provides support for the implementation of distributed data acquisition and control systems, and functionality for log and alarm management, message driven communication and hardware devices management. The first version of the MASS system, which will comply with the CTA requirements and guidelines, will be tested on the ASTRI SST-2M prototype. In this contribution we present the interface definitions of the MASS high level components in charge of the ASTRI SST-2M observation scheduling, telescope control and monitoring, and data taking. Particular emphasis is given to their potential reuse for the ASTRI/CTA mini-array.

  4. Development of 2D Bi-SQUID Arrays with High Linearity

    CERN Document Server

    Berggren, S; Longhini, P; Palacios, A; Mukhanov, O A; de Escobar, A Leese; Taylor, B J; de Andrade, M C; Nisenoff, M; Fagaly, R L; Wong, T; Cho, E; Wong, E; In, V

    2013-01-01

    We develop a two-dimensional (2D) Superconducting Quantum Interference Filter (SQIF) array based on recently introduced high-linearity tri-junction bi-SQUIDs. Our bi-SQUID SQIF array design is based on a tight integration of individual bi- SQUID cells sharing inductances with adjacent cells. We provide extensive computer simulations, analysis and experimental measurements, in which we explore the phase dynamics and linearity of the array voltage response. The non-uniformity in inductances of the bi-SQUIDs produces a pronounced zero-field single antipeak in the voltage response. The anti-peak linearity and size can be optimized by varying the critical current of the additional junction of each bi-SQUID. The layout implementation of the tight 2D array integration leads to a distinct geometrical diamond shape formed by the merged dual bi-SQUID cells. Different size 2D arrays are fabricated using standard HYPRES niobium 4.5 kA/cm2 fabrication process. The measured linearity, power gain, and noise properties will ...

  5. Highly Mass-Sensitive Thin Film Plate Acoustic Resonators (FPAR)

    Science.gov (United States)

    Arapan, Lilia; Alexieva, Gergana; Avramov, Ivan D.; Radeva, Ekaterina; Strashilov, Vesseline; Katardjiev, Ilia; Yantchev, Ventsislav

    2011-01-01

    The mass sensitivity of thin aluminum nitride (AlN) film S0 Lamb wave resonators is theoretically and experimentally studied. Theoretical predictions based on modal and finite elements method analysis are experimentally verified. Here, two-port 888 MHz synchronous FPARs are micromachined and subsequently coated with hexamethyl-disiloxane(HMDSO)-plasma-polymerized thin films of various thicknesses. Systematic data on frequency shift and insertion loss versus film thickness are presented. FPARs demonstrate high mass-loading sensitivity as well as good tolerance towards the HMDSO viscous losses. Initial measurements in gas phase environment are further presented. PMID:22163994

  6. Highly mass-sensitive thin film plate acoustic resonators (FPAR).

    Science.gov (United States)

    Arapan, Lilia; Alexieva, Gergana; Avramov, Ivan D; Radeva, Ekaterina; Strashilov, Vesseline; Katardjiev, Ilia; Yantchev, Ventsislav

    2011-01-01

    The mass sensitivity of thin aluminum nitride (AlN) film S0 Lamb wave resonators is theoretically and experimentally studied. Theoretical predictions based on modal and finite elements method analysis are experimentally verified. Here, two-port 888 MHz synchronous FPARs are micromachined and subsequently coated with hexamethyl-disiloxane(HMDSO)-plasma-polymerized thin films of various thicknesses. Systematic data on frequency shift and insertion loss versus film thickness are presented. FPARs demonstrate high mass-loading sensitivity as well as good tolerance towards the HMDSO viscous losses. Initial measurements in gas phase environment are further presented.

  7. Design and Fabrication of High Sensitive Piezoresistive MEMS Accelerometer

    Directory of Open Access Journals (Sweden)

    JOSHI A.B

    2008-04-01

    Full Text Available This paper addresses the design and fabrication of high sensitive single axis piezoresistive micro-accelerometer for 50 g application. MEMS based accelerometer structure comprise of flexure fixed at one end and having attached proof mass at other end. This structure is designed and simulated using Coventorware. The simulation results show the sensitivity of 4mV/g. The structure is fabricated in N type silicon (100 substrate using Silicon bulk micromachining. This paper also discuses the use of PECVD Si3N4 layer as a masking material for silicon micromachining and process flow for accelerometer.

  8. Cardiac troponins and high-sensitivity cardiac troponin assays.

    Science.gov (United States)

    Conrad, Michael J; Jarolim, Petr

    2014-03-01

    Measurement of circulating cardiac troponins I and T has become integral to the diagnosis of myocardial infarction. This article discusses the structure and function of the troponin complex and the release of cardiac troponin molecules from the injured cardiomyocyte into the circulation. An overview of current cardiac troponin assays and their classification according to sensitivity is presented. The diagnostic criteria, role, and usefulness of cardiac troponin for myocardial infarction are discussed. In addition, several examples are given of the usefulness of high-sensitivity cardiac troponin assays for short-term and long-term prediction of adverse events.

  9. Highly Mass-Sensitive Thin Film Plate Acoustic Resonators (FPAR

    Directory of Open Access Journals (Sweden)

    Ventsislav Yantchev

    2011-07-01

    Full Text Available The mass sensitivity of thin aluminum nitride (AlN film S0 Lamb wave resonators is theoretically and experimentally studied. Theoretical predictions based on modal and finite elements method analysis are experimentally verified. Here, two-port 888 MHz synchronous FPARs are micromachined and subsequently coated with hexamethyl-disiloxane(HMDSO-plasma-polymerized thin films of various thicknesses. Systematic data on frequency shift and insertion loss versus film thickness are presented. FPARs demonstrate high mass-loading sensitivity as well as good tolerance towards the HMDSO viscous losses. Initial measurements in gas phase environment are further presented.

  10. chipD: a web tool to design oligonucleotide probes for high-density tiling arrays

    Science.gov (United States)

    Dufour, Yann S.; Wesenberg, Gary E.; Tritt, Andrew J.; Glasner, Jeremy D.; Perna, Nicole T.; Mitchell, Julie C.; Donohue, Timothy J.

    2010-01-01

    chipD is a web server that facilitates design of DNA oligonucleotide probes for high-density tiling arrays, which can be used in a number of genomic applications such as ChIP-chip or gene-expression profiling. The server implements a probe selection algorithm that takes as an input, in addition to the target sequences, a set of parameters that allow probe design to be tailored to specific applications, protocols or the array manufacturer’s requirements. The algorithm optimizes probes to meet three objectives: (i) probes should be specific; (ii) probes should have similar thermodynamic properties; and (iii) the target sequence coverage should be homogeneous and avoid significant gaps. The output provides in a text format, the list of probe sequences with their genomic locations, targeted strands and hybridization characteristics. chipD has been used successfully to design tiling arrays for bacteria and yeast. chipD is available at http://chipd.uwbacter.org/. PMID:20529880

  11. The european FAZIA initiative: a high-performance digital telescope array for heavy-ion studies

    CERN Document Server

    Casini, G; Pasquali, G; Pastore, G; Bini, M; Carboni, S; Olmi, A; Piantelli, S; Poggi, G; Stefanini, A; Valdre', S; Bonnet, E; Borderie, B; Bougault, R; Bruno, M; Chbihi, A; Cinausero, M; Degerlier, M; Edelbruck, P; Frankland, J D; Gramegna, F; Gruyer, D; Guerzoni, M; Kordjasz, A; Kozik, T; Neindre, N Le; Lopez, O; Marchi, T; Marini, P; Morelli, L; Ordine, A; Parlog, M; Rivet, M F; Rosato, E; Salomon, F; Spadaccini, G; Twarog, T; Vient, E; Vigilante, M

    2013-01-01

    The european Fazia collaboration aims at building a new modular array for charged product identification to be employed for heavy-ion studies. The elementary module of the array is a Silicon-Silicon-CsI telescope, optimized for ion identification also via pulse shape analysis. The achievement of top performances imposes specific electronics which has been developed by FAZIA and features high quality charge and current preamplifiers, coupled to fully digital front-end. During the initial R&D phase, original and novel solutions have been tested in prototypes, obtaining unprecedented ion identification capabilities. FAZIA is now constructing a demonstrator array consisting of about two hundreds telescopes arranged in a compact and transportable configuration. In this contribution, we mainly summarize some aspects studied by FAZIA to improve the ion identification. Then we will briefly discuss the FAZIA program centered on experiments to be done with the demonstrator. First results on the isospin dynamics obt...

  12. Characterization of SPAD Array for Multifocal High-Content Screening Applications

    Directory of Open Access Journals (Sweden)

    Anthony Tsikouras

    2016-10-01

    Full Text Available Current instruments used to detect specific protein-protein interactions in live cells for applications in high-content screening (HCS are limited by the time required to measure the lifetime. Here, a 32 × 1 single-photon avalanche diode (SPAD array was explored as a detector for fluorescence lifetime imaging (FLIM in HCS. Device parameters and characterization results were interpreted in the context of the application to determine if the SPAD array could satisfy the requirements of HCS-FLIM. Fluorescence lifetime measurements were performed using a known fluorescence standard; and the recovered fluorescence lifetime matched literature reported values. The design of a theoretical 32 × 32 SPAD array was also considered as a detector for a multi-point confocal scanning microscope.

  13. High Sensitivity Very Low Frequency Receiver for Earthquake Data Acquisition.

    Science.gov (United States)

    Munir, A.; Najmurrokhman, A.

    2017-03-01

    high sensitivity very low frequency (VLF) receiver is developed based on AD744 monolithic operational amplifier (Op-Amp) for earthquake data acquisition. In research related natural phenomena such as atmospheric noise, lightning and earthquake, a VLF receiver particularly with high sensitivity is utterly required due to the low power of VLF wave signals received by the antenna. The developed receiver is intended to have high sensitivity reception for the signals in frequency range of 10-30kHz allocated for earthquake observation. The VLF receiver which is portably designed is also equipped with an output port connectable to the soundcard of personal computer for further data acquisition. After obtaining the optimum design, the hardware realization is implemented on a printed circuit board (PCB) for experimental characterization. It shows that the sensitivity of realized VLF receiver is almost linear in the predefined frequency range for the input signals lower than -12dBm and to be quadratic for the higher level input signals.

  14. 基于TiO2纳米管阵列的高效正面透光型染料敏化太阳能电池的制备及其光电性能%Fabrication and Photovoltaic Performance of High Efficiency Front-Illuminated Dye-Sensitized Solar Cell Based on Ordered TiO2 Nanotube Arrays

    Institute of Scientific and Technical Information of China (English)

    高素雯; 兰章; 吴晚霞; 阙兰芳; 吴季怀; 林建明; 黄妙良

    2014-01-01

    An efficient front-il uminated dye-sensitized solar cell(DSSC) based on ordered TiO2 nanotube (TNT) arrays was prepared. Sintering at 450 °C avoided damage of the ordered TNTs during HF treatment. Fast electron transport channels were maintained in the membrane, for efficient charge transportat in the DSSC. The sintered TNT membranes were subsequently treated with HF, TiCl4, and HF combined with TiCl4. This formed a rougher surface, and al owed increased dye loadings. The increased dye loading improved the light harvesting efficiency of the photoanode at 300-570 nm wavelength range, which is the main absorption region of the adsorbed dye. The adsorbed dye had a low absorption at 570-800 nm wavelength range. The enhanced light harvesting efficiency of the photoanode originated from its increased diffuse reflectance. The incident-photon-to-current and absorbed-photon-to-current conversion efficiencies were increased over the entire 300-800 nm wavelength range. This resulted in an increased short-circuit current density of the DSSC. Electrochemical impedance spectroscopy indicated that electron transport and related parameters including charge transport resistance, interfacial charge recombination resistance, distributed chemical capacitance, electron lifetime, effective electron diffusion length, and col ection efficiency were significantly improved in the DSSC containing the treated TNT photoanode. This also resulted in an enhanced photovoltaic performance. The maximum power conversion efficiency from combining HF and TiCl4 treatments was 7.30%, which was a 35.69%enhancement compared with the non-treated DSSC (5.38%).%报道了一种基于TiO2纳米管(TNT)阵列正面透光型光阳极的高效染料敏化太阳能电池.将TNTs在450°C烧结后能避免其有序结构在HF处理过程中被破坏,使膜内高速电子传输通道被保留,有利于染料敏化太阳能电池(DSSC)实现高速电荷传输.再用HF、TiCl4、HF和TiCl4混合等溶剂对TNTs

  15. High Sensitivity Polymer Optical Fiber-Bragg-Grating-Based Accelerometer

    DEFF Research Database (Denmark)

    Stefani, Alessio; Andresen, Søren; Yuan, Wu

    2012-01-01

    We report on the fabrication and characterization of the first accelerometer based on a polymer optical fiber Bragg grating (FBG) for operation at both 850 and 1550 nm. The devices have a flat frequency response over a 1-kHz bandwidth and a resonance frequency of about 3 kHz. The response is linear...... up to at least 15 g and sensitivities as high as 19 pm/g (shift in resonance wavelength per unit acceleration) have been demonstrated. Given that 15 g corresponds to a strain of less than 0.02% and that polymer fibers have an elastic limit of more than 1%, the polymer FBG accelerometer can measure...... very strong accelerations. We compare with corresponding silica FBG accelerometers and demonstrate that using polymer FBGs improves the sensitivity by more than a factor of four and increases the figure of merit, defined as the sensitivity times the resonance frequency squared....

  16. Synthesis of Highly Stable Silver-Loaded Vertical ZnO Nanowires Array and its Acetylene Sensing Properties

    Science.gov (United States)

    Uddin, Abu Sadat Mohammad Iftekhar; Chung, Gwiy-Sang

    2016-09-01

    A silver-loaded one-dimensional (1D) vertical ZnO nanowires (NWs) array synthesized by a facile seed mediated hydrothermal-RF magnetron sputtering method has been investigated for the fabrication of a highly stable and reproducible acetylene (C2H2) gas sensor. Successful immobilization of silver nanoparticles (NPs) as a sensitizer on the ZnO NWs array significantly enhanced the C2H2 sensing properties and showed a stable sensing performance. The grown structure exhibited high response magnitude (30.8 at 1000ppm), short response time (43s) and excellent selectivity at 220∘C. The enhanced performance can probably be accounted for the effect of combining the highly orientated ZnO NWs and catalytically active silver-based network. The superior sensing features toward C2H2 along with broad detection range (1-1000ppm), outstanding stability and excellent reproducibility indicate that the sensor is a promising candidate for practical applications.

  17. Are Inflationary Predictions Sensitive to Very High Energy Physics?

    CERN Document Server

    Burgess, C P; Lemieux, F; Holman, R

    2003-01-01

    It has been proposed that the successful inflationary description of density perturbations on cosmological scales is sensitive to the details of physics at extremely high (trans-Planckian) energies. We test this proposal by examining how inflationary predictions depend on higher-energy scales within a simple model where the higher-energy physics is well understood. We find the best of all possible worlds: inflationary predictions are robust against the vast majority of high-energy effects, but can be sensitive to some effects in certain circumstances, in a way which does not violate ordinary notions of decoupling. This implies both that the comparison of inflationary predictions with CMB data is meaningful, and that it is also worth searching for small deviations from the standard results in the hopes of learning about very high energies.

  18. Design of highly sensitive multichannel bimetallic photonic crystal fiber biosensor

    Science.gov (United States)

    Hameed, Mohamed Farhat O.; Alrayk, Yassmin K. A.; Shaalan, Abdelhamid A.; El Deeb, Walid S.; Obayya, Salah S. A.

    2016-10-01

    A design of a highly sensitive multichannel biosensor based on photonic crystal fiber is proposed and analyzed. The suggested design has a silver layer as a plasmonic material coated by a gold layer to protect silver oxidation. The reported sensor is based on detection using the quasi transverse electric (TE) and quasi transverse magnetic (TM) modes, which offers the possibility of multichannel/multianalyte sensing. The numerical results are obtained using a finite element method with perfect matched layer boundary conditions. The sensor geometrical parameters are optimized to achieve high sensitivity for the two polarized modes. High-refractive index sensitivity of about 4750 nm/RIU (refractive index unit) and 4300 nm/RIU with corresponding resolutions of 2.1×10-5 RIU, and 2.33×10-5 RIU can be obtained according to the quasi TM and quasi TE modes of the proposed sensor, respectively. Further, the reported design can be used as a self-calibration biosensor within an unknown analyte refractive index ranging from 1.33 to 1.35 with high linearity and high accuracy. Moreover, the suggested biosensor has advantages in terms of compactness and better integration of microfluidics setup, waveguide, and metallic layers into a single structure.

  19. Performance of compact TES arrays with integrated high-fill-fraction X-ray absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Lindeman, Mark A. E-mail: lindeman@lheapop.gsfc.nasa.gov; Bandler, Simon; Brekosky, Regis P.; Chervenak, James A.; Figueroa-Feliciano, Enectali; Finkbeiner, Fred M.; Kelley, Richard L.; Saab, Tarek; Stahle, Caroline K.; Talley, D.J

    2004-03-11

    We have recently produced and tested two-dimensional arrays of Mo/Au transition-edge-sensor (TES) calorimeters with Bi/Cu absorbers. The arrays represent a significant step towards meeting the specifications of NASA's Constellation-X mission. The calorimeters are compactly spaced within 5x5 arrays of 250 {mu}m square pixels necessary for an angular resolution of 5 arcsec. Lithographically produced absorbers hang over the substrate and wiring between the TESs for high filling fraction and high quantum efficiency. We designed the calorimeters with heat capacities and thermal couplings such that X-rays produce pulses with fall times of approximately 300 {mu}s to allow relatively high count rates with low dead time. We read out up to four of the pixels simultaneously. The arrays demonstrated very good energy resolution (5 eV at 1.5 keV and 7 eV at 6 keV) and little crosstalk between neighboring pixels.

  20. Dynamic high pressure measurements using a Fiber Bragg Grating probe and an arrayed waveguide grating spectrometer

    Science.gov (United States)

    Barbarin, Y.; Lefrançois, A.; Magne, S.; Woirin, K.; Sinatti, F.; Osmont, A.; Luc, J.

    2016-08-01

    High pressure shock profiles are monitored using a long Fiber Bragg Grating (FBG). Such thin probe, with a diameter of typically 150 μm, can be inserted directly into targets for shock plate experiments. The shocked FBG's portion is stressed under compression, which increases its optical group index and shortens its grating period. Placed along the 2D symmetrical axis of the cylindrical target, the second effect is stronger and the reflected spectrum shifts towards the shorter wavelengths. The dynamic evolution of FBG spectra is recorded with a customized Arrayed Waveguide Grating (AWG) spectrometer covering the C+L band. The AWG provides 40 channels of 200-GHz spacing with a special flattop design. The output channels are fiber-connected to photoreceivers (bandwidth: DC - 400 MHz or 10 kHz - 2 GHz). The experimental setup was a symmetric impact, completed in a 110-mm diameter single-stage gas gun with Aluminum (6061T6) impactors and targets. The FBG's central wavelength was 1605 nm to cover the pressure range of 0 - 8 GPa. The FBG was 50-mm long as well as the target's thickness. The 20-mm thick impactor maintains a shock within the target over a distance of 30 mm. For the impact at 522 m/s, the sustained pressure of 3.6 GPa, which resulted in a Bragg shift of (26.2 +/- 1.5) nm, is measured and retrieved with respectively thin-film gauges and the hydrodynamic code Ouranos. The shock sensitivity of the FBG is about 7 nm/GPa, but it decreases with the pressure level. The overall spectra evolution is in good agreement with the numerical simulations.

  1. Synthesis of ZnO-TiO{sub 2} core-shell long nanowire arrays and their application on dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Feng Yamin [Department of Physics, Institute of Nanoscience and Nanotechnology, Central China Normal University, Wuhan 430079 (China); Ji Xiaoxu [School of Physics and Electronic Engineering, Nanyang Normal University, Nanyang 473003 (China); Duan Jinxia; Zhu Jianhui; Jiang Jian; Ding Hao; Meng Gaoxiang; Ding Ruimin; Liu Jinping [Department of Physics, Institute of Nanoscience and Nanotechnology, Central China Normal University, Wuhan 430079 (China); Hu Anzheng [School of Physics and Electronic Engineering, College of Xiangfan, Xiangfan 441813 (China); Huang Xintang, E-mail: xthuang@phy.ccnu.edu.cn [Department of Physics, Institute of Nanoscience and Nanotechnology, Central China Normal University, Wuhan 430079 (China)

    2012-06-15

    Long ZnO nanowire arrays (NAs) grown on fluorine-doped tin oxide (FTO) glasses have been synthesized via a facile hydrothermal method without refreshing the reaction solution and applied as the precursor. By adjusting growth conditions, ZnO NAs with tunable lengths can be achieved. A nanocomposite made of ZnO nanowire core and TiO{sub 2} shell was further realized by a novel 'fast-dip-coating' method conducted in a Ti(OC{sub 4}H{sub 9}){sub 4}-dissolved ethanol solution. The formed ZnO-TiO{sub 2} core-shell NAs on FTO substrates were applied as electrodes for dye sensitized solar cells (DSSCs). It is found that both the TiO{sub 2} coating and NAs length play important roles in the enhancement of photoelectric conversion efficiency (PCE) of DSSCs. When the length of ZnO-TiO{sub 2} NAs reaches up to 14 {mu}m, the electrode can exhibit a maximum PCE as high as 3.80%, which is 2.6 times higher than that of pure ZnO NAs. - Graphical abstract: ZnO nanowire arrays in the length of 14 {mu}m have been successfully synthesized on the FTO substrate and coated with a thin shell of TiO{sub 2}; the ZnO-TiO{sub 2} electrodes applied in DSSCs exhibit great photoelectric conversion efficiency as high as 3.80%. Highlights: Black-Right-Pointing-Pointer Long ZnO nanowire arrays have been synthesized by using hydrothermal method. Black-Right-Pointing-Pointer A TiO{sub 2} shell outside of ZnO nanowire is introduced by a fast dip-coating method. Black-Right-Pointing-Pointer ZnO and ZnO-TiO{sub 2} core-shell nanowires are applied as the electrodes for DSSCs. Black-Right-Pointing-Pointer The maximum conversion efficiency of ZnO-TiO{sub 2} electrode reaches to 3.80%.

  2. Highly Oriented ZnO Rod Arrays on Si Substrates from Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    LIU Changsong; LI Zhiwen; ZHANG Qifeng

    2008-01-01

    Ordered zinc oxide (ZnO) rod arrays with very high orientation were fabricated on Si substrates by using a solution method. The substrate surfaces were functionalized by Self-Assembly Monolayers(SAMs). In the very early growth stage, the oriented ZnO crystals had already grown, which appeared to be themain reason why ZnO nanorods showed very high orientation. The un-dense and un-uniform SAMs provided a surface that was heterogeneous to ZnO nucleation. Consequently, highly oriented ZnO rods were selectively grown on the "coin-like" SAM-uncovered regions. The route developed here can provide some helpful information to control the nucleation and orientation of ZnO in aqueous solution. Also, the site-selective growth mechanisms can indicate a clue to grow patterned highly oriented ZnO nanorod arrays by the organic template.

  3. Highly sensitive hydrogen sulfide (H2 S) gas sensors from viral-templated nanocrystalline gold nanowires

    Science.gov (United States)

    Moon, Chung Hee; Zhang, Miluo; Myung, Nosang V.; Haberer, Elaine D.

    2014-04-01

    A facile, site-specific viral-templated assembly method was used to fabricate sensitive hydrogen sulfide (H2S) gas sensors at room temperature. A gold-binding M13 bacteriophage served to organize gold nanoparticles into linear arrays which were used as seeds for subsequent nanowire formation through electroless deposition. Nanowire widths and densities within the sensors were modified by electroless deposition time and phage concentration, respectively, to tune device resistance. Chemiresistive H2S gas sensors with superior room temperature sensing performance were produced with sensitivity of 654%/ppmv, theoretical lowest detection limit of 2 ppbv, and 70% recovery within 9 min for 0.025 ppmv. The role of the viral template and associated gold-binding peptide was elucidated by removing organics using a short O2 plasma treatment followed by an ethanol dip. The template and gold-binding peptide were crucial to electrical and sensor performance. Without surface organics, the resistance fell by several orders of magnitude, the sensitivity dropped by more than a factor of 100 to 6%/ppmv, the lower limit of detection increased, and no recovery was detected with dry air flow. Viral templates provide a novel, alternative fabrication route for highly sensitive, nanostructured H2S gas sensors.

  4. Amorphous Silicon-Germanium Films with Embedded Nanocrystals for Thermal Detectors with Very High Sensitivity

    Directory of Open Access Journals (Sweden)

    Cesar Calleja

    2016-01-01

    Full Text Available We have optimized the deposition conditions of amorphous silicon-germanium films with embedded nanocrystals in a plasma enhanced chemical vapor deposition (PECVD reactor, working at a standard frequency of 13.56 MHz. The objective was to produce films with very large Temperature Coefficient of Resistance (TCR, which is a signature of the sensitivity in thermal detectors (microbolometers. Morphological, electrical, and optical characterization were performed in the films, and we found optimal conditions for obtaining films with very high values of thermal coefficient of resistance (TCR = 7.9% K−1. Our results show that amorphous silicon-germanium films with embedded nanocrystals can be used as thermosensitive films in high performance infrared focal plane arrays (IRFPAs used in commercial thermal cameras.

  5. NEMS Capacitive Sensors for Highly Sensitive, Label-Free Nucleic-Acid Analysis

    Science.gov (United States)

    Mannoor, Manu Sebastian; James, Teena; Ivanov, Dentcho V.; Beadling, Les; Braunlin, William

    A highly sensitive NEMS capacitive sensor with electrode separation in the order of Debye length is fabricated for label free DNA analysis. The use of nano-scale electrode separation provides better insight in to the target-probe interaction which was not previously attainable with macro or even micro scale devices. As the double layers from both the capacitive electrodes merge together and occupy a major fraction of the capacitive volume, the contribution from bulk sample resistance and noises due to electrode polarization effects are eliminated. The dielectric properties during hybridization reaction were measured using 10-mer nucleotide sequences. A 45-50% change in relative permittivity (capacitance) was observed due to DNA hybridization at 10Hz. Capacitive sensors with 30nm electrode separation were fabricated using standard silicon micro/nano technology and show promise for future electronic DNA arrays and high throughput screening of nucleic acid samples.

  6. Ultra-Fast Processing of Gigapixel Tissue MicroArray Images Using High Performance Computing

    OpenAIRE

    Yinhai Wang; David McCleary; Ching-Wei Wang; Paul Kelly; Jackie James; Fennell, Dean A; Peter Hamilton

    2010-01-01

    Background: Tissue MicroArrays (TMAs) are a valuable platform for tissue based translational research and the discovery of tissue biomarkers. The digitised TMA slides or TMA Virtual Slides, are ultra-large digital images, and can contain several hundred samples. The processing of such slides is time-consuming, bottlenecking a potentially high throughput platform. Methods: A High Performance Computing (HPC) platform for the rapid analysis of TMA virtual slides is presented in this study. Using...

  7. Highly Ordered Carbon Nanotube Arrays with Open Ends Grown in Anodic Alumina Nanoholes

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Highly ordered multiwalled carbon nanotube arrays were fabricated by pyrolysis of acetylene within anodic alumina templates.Nanotubes are very uniform in diameter and open at both ends. High resolution transmission electron microscopy and electron diffraction analysis show that the carbon nanotubes are well graphitized. These standing and open carbon nanotubes are possible to offer a potential elegant technique for electron emitting devices,chemical functionalization and nanotube composites.

  8. Modeling change from large-scale high-dimensional spatio-temporal array data

    Science.gov (United States)

    Lu, Meng; Pebesma, Edzer

    2014-05-01

    The massive data that come from Earth observation satellite and other sensors provide significant information for modeling global change. At the same time, the high dimensionality of the data has brought challenges in data acquisition, management, effective querying and processing. In addition, the output of earth system modeling tends to be data intensive and needs methodologies for storing, validation, analyzing and visualization, e.g. as maps. An important proportion of earth system observations and simulated data can be represented as multi-dimensional array data, which has received increasingly attention in big data management and spatial-temporal analysis. Study cases will be developed in natural science such as climate change, hydrological modeling, sediment dynamics, from which the addressing of big data problems is necessary. Multi-dimensional array-based database management and analytics system such as Rasdaman, SciDB, and R will be applied to these cases. From these studies will hope to learn the strengths and weaknesses of these systems, how they might work together or how semantics of array operations differ, through addressing the problems associated with big data. Research questions include: • How can we reduce dimensions spatially and temporally, or thematically? • How can we extend existing GIS functions to work on multidimensional arrays? • How can we combine data sets of different dimensionality or different resolutions? • Can map algebra be extended to an intelligible array algebra? • What are effective semantics for array programming of dynamic data driven applications? • In which sense are space and time special, as dimensions, compared to other properties? • How can we make the analysis of multi-spectral, multi-temporal and multi-sensor earth observation data easy?

  9. Self-assembled random arrays: high-performance imaging and genomics applications on a high-density microarray platform

    Science.gov (United States)

    Barker, David L.; Theriault, Greg; Che, Diping; Dickinson, Todd; Shen, Richard; Kain, Robert C.

    2003-07-01

    Illumina is developing a BeadArrayTM technology that supports SNP genotyping, mRNA expression analysis and protein expression analysis on the same platform. We use fiber-optic bundles with a density of approximately 40,000 fibers/mm2. At hte end of each fiber, a derivatized silica bead forms an array element for reading out a genotyping or expression assay data point. Each bead contains oligonucleotide probes that hybridize with high specificity to complementary sequences in a complex nucleic acid mixture. We derivatize the beads in bulk, pool them to form a quality-controlled source of microarray elements, and allow them to assemble spontaneously into pits etched into the end of each optical fiber bundle. We load our fiber bundles, containing 49,777 fibers, with up to 1520 different bead types. The presence of many beads of each type greatly improves the accuracy of each assay. As the final step in our manufacturing process, we decode the identity of each bead by a series of rapid hybridizations with fluroescent oligos. Decoding accuracy and the number of beads of each type is recorded for each array. Decoding also serves as a quality control procedure for the performance of each element in the array. To facilitate high-throughput analysis of many samples, the fiber bundles are arranged in an array matrix (SentrixTM arrays). Using a 96-bundle array matrix, up to 1520 assays can be performed on each of 96 samples simultaneously for a total of 145,920 assays. Using a 384-bundle array matrix, up to 583,680 assays can be performed simultaneously. The BeadArray platform is the highest density microarray in commercial use, requiring development of a high-performance array scanner. To meet this need, we developed the SherlockTM system, a laser-scanning confocal imaging system that automatically scans all 96 bundles of an array matrix at variable resolution down to 0.8 micron. The system scans with both 532 and 635 nm lasers simultaneously, collecting two fluorescence

  10. Investigation on transmission and reflection characteristics of plasma array to 6 GHz high-power microwave

    Science.gov (United States)

    Yang, Liu; Yang, Zhongcun; Wan, Jianing; Liu, Hao

    2016-10-01

    For the safety of electronic equipment, a double-layer barrier of cylindrical plasma array was designed, and its protective performance to high-power microwave (HPM) were analyzed and the protective performance experiment was conducted. Combining the density distribution characteristic of the discharge plasma, the shielding effectiveness of the double-layer plasma on 6GHz HPM pulse was studied. The experiment results indicate that the protective effectiveness of two layers plasma array is better than that of one layer. Two layers plasma array can make the peak electric field of transmission waveform less than interference threshold of electronic equipment to achieve better protection effectiveness. Transmission attenuation of one layer and two layers plasma array to HPM can reach -6.6066dB and -24.9357dB. The results also show that for the existence of multiple reflection, even the plasma electron density is not high enough, it can realize a strong attenuation. The experiment results in this paper are of great significance in protecting against HPM and electromagnetic pulse.

  11. Application of HEMT for multiplexing large arrays of high impedance LTDs

    Energy Technology Data Exchange (ETDEWEB)

    Benoit, A.; Camus, Ph. E-mail: camus@grenoble.cnrs.fr; Cavanna, A.; Elhdiy, A.; Jin, Y.; Leclercq, S

    2004-03-11

    The development of large arrays of detectors requires using a proximate electronics at low temperatures for signal multiplexing and amplification. We report the use of commercial High Electronic Mobility Transistors (HEMT) for multiplexing signals from high impedance LTD arrays (typ. 10-100 M{omega}). The electronic architecture is based on HEMTs cooled at 0.1 K for the multiplexer and a JFET amplifier cooled at 100 K with <1 nV/Hz{sup 1/2} noise figure. For this time-multiplexing scheme, a capacitor is used to integrate the signal between measurements. Two main solutions are compared for the detectors polarization: the first uses a classical resistive method; the second uses a common capacitor allowing to polarize the detectors individually. The multiplexing ratio is mainly limited by the amplifier noise to about 20 detectors per amplifier with a pixel sampling rate of about 60 Hz. A specific development of HEMT arrays with Quantum Point Contacts (QPC-HEMT) with very small grid-to-channel capacitor ({approx}1 fF) allows minimizing the transient effects and realizing a close integration with the LTD arrays.

  12. Demonstration of nanoimprinted hyperlens array for high-throughput sub-diffraction imaging

    Science.gov (United States)

    Byun, Minsueop; Lee, Dasol; Kim, Minkyung; Kim, Yangdoo; Kim, Kwan; Ok, Jong G.; Rho, Junsuk; Lee, Heon

    2017-04-01

    Overcoming the resolution limit of conventional optics is regarded as the most important issue in optical imaging science and technology. Although hyperlenses, super-resolution imaging devices based on highly anisotropic dispersion relations that allow the access of high-wavevector components, have recently achieved far-field sub-diffraction imaging in real-time, the previously demonstrated devices have suffered from the extreme difficulties of both the fabrication process and the non-artificial objects placement. This results in restrictions on the practical applications of the hyperlens devices. While implementing large-scale hyperlens arrays in conventional microscopy is desirable to solve such issues, it has not been feasible to fabricate such large-scale hyperlens array with the previously used nanofabrication methods. Here, we suggest a scalable and reliable fabrication process of a large-scale hyperlens device based on direct pattern transfer techniques. We fabricate a 5 cm × 5 cm size hyperlenses array and experimentally demonstrate that it can resolve sub-diffraction features down to 160 nm under 410 nm wavelength visible light. The array-based hyperlens device will provide a simple solution for much more practical far-field and real-time super-resolution imaging which can be widely used in optics, biology, medical science, nanotechnology and other closely related interdisciplinary fields.

  13. High-Accuracy, Compact Scanning Method and Circuit for Resistive Sensor Arrays

    Directory of Open Access Journals (Sweden)

    Jong-Seok Kim

    2016-01-01

    Full Text Available The zero-potential scanning circuit is widely used as read-out circuit for resistive sensor arrays because it removes a well known problem: crosstalk current. The zero-potential scanning circuit can be divided into two groups based on type of row drivers. One type is a row driver using digital buffers. It can be easily implemented because of its simple structure, but we found that it can cause a large read-out error which originates from on-resistance of the digital buffers used in the row driver. The other type is a row driver composed of operational amplifiers. It, very accurately, reads the sensor resistance, but it uses a large number of operational amplifiers to drive rows of the sensor array; therefore, it severely increases the power consumption, cost, and system complexity. To resolve the inaccuracy or high complexity problems founded in those previous circuits, we propose a new row driver which uses only one operational amplifier to drive all rows of a sensor array with high accuracy. The measurement results with the proposed circuit to drive a 4 × 4 resistor array show that the maximum error is only 0.1% which is remarkably reduced from 30.7% of the previous counterpart.

  14. Simultaneous detection for three kinds of veterinary drugs: Chloramphenicol, clenbuterol and 17-beta-estradiol by high-throughput suspension array technology

    Energy Technology Data Exchange (ETDEWEB)

    Liu Nan; Su Pu [Institute of Hygiene and Environmental Medicine, Tianjin 300050 (China); Gao Zhixian [Institute of Hygiene and Environmental Medicine, Tianjin 300050 (China)], E-mail: gaozhx@163.com; Zhu Maoxiang; Yang Zhihua; Pan Xiujie [Institute of Radiation Medicine, Beijing 100850 (China); Fang Yanjun; Chao Fuhuan [Institute of Hygiene and Environmental Medicine, Tianjin 300050 (China)

    2009-01-19

    Suspension array technology for simultaneous detection of three kinds of veterinary drugs, chloramphenicol (CAP), clenbuterol and 17-beta-estradiol has been developed. Conjugates of chloramphenicol and clenbuterol coupled with bovine serum albumin were synthesized and purified. Probes of suspension array were constituted by coupling the three conjugates on the fluorescent microspheres/beads and the microstructures of the beads' surface were observed by scanning electron microscopy which was a direct confirmation for the successful conjugates' coupling. The optimal addition of conjugates and the amounts of antibodies were optimized and selected, respectively. Standard curves were plotted and the coefficient of determination-R{sup 2} was greater than 0.989 which suggested good logistic correlation. The detection ranges for the three veterinary drugs are 40-6.25 x 10{sup 5} ng L{sup -1}, 50-7.81 x 10{sup 5} ng L{sup -1} and 1 x 10{sup 3-}7.29 x 10{sup 5} ng L{sup -1}, respectively and the lowest detection limits (LDLs) of them are 40, 50 and 1000 ng L{sup -1}, respectively. The suspension array is specific and has no significant cross-reactivity with other chemicals. Meanwhile, unknown samples were detected by suspension array and ELISA in comparison with each other. The errors between found and real for the detection of the unknown samples were relatively small to both of the two methods, whereas, the detection ranges of suspension array are broader and sensitive than that of the traditional ELISA. The high-throughput suspension array is proved to be a novel method for multi-analysis of veterinary drugs with simple operation, high sensitivity and low cost.

  15. Photolithographic Synthesis of High-Density DNA and RNA Arrays on Flexible, Transparent, and Easily Subdivided Plastic Substrates.

    Science.gov (United States)

    Holden, Matthew T; Carter, Matthew C D; Wu, Cheng-Hsien; Wolfer, Jamison; Codner, Eric; Sussman, Michael R; Lynn, David M; Smith, Lloyd M

    2015-11-17

    The photolithographic fabrication of high-density DNA and RNA arrays on flexible and transparent plastic substrates is reported. The substrates are thin sheets of poly(ethylene terephthalate) (PET) coated with cross-linked polymer multilayers that present hydroxyl groups suitable for conventional phosphoramidite-based nucleic acid synthesis. We demonstrate that by modifying array synthesis procedures to accommodate the physical and chemical properties of these materials, it is possible to synthesize plastic-backed oligonucleotide arrays with feature sizes as small as 14 μm × 14 μm and feature densities in excess of 125 000/cm(2), similar to specifications attainable using rigid substrates such as glass or glassy carbon. These plastic-backed arrays are tolerant to a wide range of hybridization temperatures, and improved synthetic procedures are described that enable the fabrication of arrays with sequences up to 50 nucleotides in length. These arrays hybridize with S/N ratios comparable to those fabricated on otherwise identical arrays prepared on glass or glassy carbon. This platform supports the enzymatic synthesis of RNA arrays and proof-of-concept experiments are presented showing that the arrays can be readily subdivided into smaller arrays (or "millichips") using common laboratory-scale laser cutting tools. These results expand the utility of oligonucleotide arrays fabricated on plastic substrates and open the door to new applications for these important bioanalytical tools.

  16. Development of High Sensitivity Nuclear Emulsion and Fine Grained Emulsion

    Energy Technology Data Exchange (ETDEWEB)

    Kawahara, H.; Asada, T. [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Naka, T. [Institute of Advanced Research, Nagoya University (Japan); Naganawa, N.; Kuwabara, K.; Nakamura, M. [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan)

    2014-08-15

    Nuclear emulsion is a particle detector having high spacial resolution and angular resolution. It became useful for large statistics experiment thanks to the development of automatic scanning system. In 2010, a facility for emulsion production was introduced and R and D of nuclear emulsion began at Nagoya university. In this paper, we present results of development of the high sensitivity emulsion and fine grained emulsion for dark matter search experiment. Improvement of sensitivity is achieved by raising density of silver halide crystals and doping well-adjusted amount of chemicals. Production of fine grained emulsion was difficult because of unexpected crystal condensation. By mixing polyvinyl alcohol (PVA) to gelatin as a binder, we succeeded in making a stable fine grained emulsion.

  17. Highly sensitive troponin T in patients with acute ischemic stroke

    DEFF Research Database (Denmark)

    Jensen, J K; Ueland, T; Aukrust, P;

    2012-01-01

    in decedents than in survivors. After adjustment for stroke severity, C-reactive protein, age, NT-proBNP and prior heart and/or renal failure, hsTnT levels were not a significant predictor of long-term all-cause or cardiovascular mortality. Conclusion: Elevated levels of hsTnT are frequently present......Background: Newly developed troponin assays have superior diagnostic and prognostic performance in acute coronary syndrome (ACS), when compared to conventional troponin assays; however, highly sensitive troponin has not been evaluated in patients with acute ischemic stroke. Methods: Highly...... sensitive troponin T (hsTnT) was measured daily during the first 4 days in 193 consecutive patients with acute ischemic stroke without overt ACS or atrial fibrillation. The patients were previously tested normal with a fourth-generation TnT assay. The patients were followed for 47 months, with all...

  18. High Dynamic Range Pixel Array Detector for Scanning Transmission Electron Microscopy.

    Science.gov (United States)

    Tate, Mark W; Purohit, Prafull; Chamberlain, Darol; Nguyen, Kayla X; Hovden, Robert; Chang, Celesta S; Deb, Pratiti; Turgut, Emrah; Heron, John T; Schlom, Darrell G; Ralph, Daniel C; Fuchs, Gregory D; Shanks, Katherine S; Philipp, Hugh T; Muller, David A; Gruner, Sol M

    2016-02-01

    We describe a hybrid pixel array detector (electron microscope pixel array detector, or EMPAD) adapted for use in electron microscope applications, especially as a universal detector for scanning transmission electron microscopy. The 128×128 pixel detector consists of a 500 µm thick silicon diode array bump-bonded pixel-by-pixel to an application-specific integrated circuit. The in-pixel circuitry provides a 1,000,000:1 dynamic range within a single frame, allowing the direct electron beam to be imaged while still maintaining single electron sensitivity. A 1.1 kHz framing rate enables rapid data collection and minimizes sample drift distortions while scanning. By capturing the entire unsaturated diffraction pattern in scanning mode, one can simultaneously capture bright field, dark field, and phase contrast information, as well as being able to analyze the full scattering distribution, allowing true center of mass imaging. The scattering is recorded on an absolute scale, so that information such as local sample thickness can be directly determined. This paper describes the detector architecture, data acquisition system, and preliminary results from experiments with 80-200 keV electron beams.

  19. High Dynamic Range Pixel Array Detector for Scanning Transmission Electron Microscopy

    CERN Document Server

    Tate, Mark W; Chamberlain, Darol; Nguyen, Kayla X; Hovden, Robert M; Chang, Celesta S; Deb, Pratiti; Turgut, Emrah; Heron, John T; Schlom, Darrell G; Ralph, Daniel C; Fuchs, Gregory D; Shanks, Katherine S; Philipp, Hugh T; Muller, David A; Gruner, Sol M

    2015-01-01

    We describe a hybrid pixel array detector (EMPAD - electron microscope pixel array detector) adapted for use in electron microscope applications, especially as a universal detector for scanning transmission electron microscopy. The 128 x 128 pixel detector consists of a 500 um thick silicon diode array bump-bonded pixel-by-pixel to an application-specific integrated circuit (ASIC). The in-pixel circuitry provides a 1,000,000:1 dynamic range within a single frame, allowing the direct electron beam to be imaged while still maintaining single electron sensitivity. A 1.1 kHz framing rate enables rapid data collection and minimizes sample drift distortions while scanning. By capturing the entire unsaturated diffraction pattern in scanning mode, one can simultaneously capture bright field, dark field, and phase contrast information, as well as being able to analyze the full scattering distribution, allowing true center of mass imaging. The scattering is recorded on an absolute scale, so that information such as loc...

  20. Methods for high throughput validation of amplified fragment pools of BAC DNA for constructing high resolution CGH arrays

    Directory of Open Access Journals (Sweden)

    Malloff Chad A

    2004-01-01

    Full Text Available Abstract Background The recent development of array based comparative genomic hybridization (CGH technology provides improved resolution for detection of genomic DNA copy number alterations. In array CGH, generating spotting solution is a multi-step process where bacterial artificial chromosome (BAC clones are converted to replenishable PCR amplified fragments pools (AFP for use as spotting solution in a microarray format on glass substrate. With completion of the human and mouse genome sequencing, large BAC clone sets providing complete genome coverage are available for construction of whole genome BAC arrays. Currently, Southern hybridization, fluorescent in-situ hybridization (FISH, and BAC end sequencing methods are commonly used to identify the initial BAC clone but not the end product used for spotting arrays. The AFP sequencing technique described in this study is a novel method designed to verify the identity of array spotting solution in a high throughput manner. Results We show here that Southern hybridization, FISH, and AFP sequencing can be used to verify the identity of final spotting solutions using less than 10% of the AFP product. Single pass AFP sequencing identified over half of the 960 AFPs analyzed. Moreover, using two vector primers approximately 90% of the AFP spotting solutions can be identified. Conclusions In this feasibility study we demonstrate that current methods for identifying initial BAC clones can be adapted to verify the identity of AFP spotting solutions used in printing arrays. Of these methods, AFP sequencing proves to be the most efficient for large scale identification of spotting solution in a high throughput manner.