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Sample records for matched silicon geranium

  1. Graded Index Silicon Geranium on Lattice Matched Silicon Geranium Semiconductor Alloy

    NASA Technical Reports Server (NTRS)

    Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor); Elliott, James R., Jr. (Inventor); Stoakley, Diane M. (Inventor)

    2009-01-01

    A lattice matched silicon germanium (SiGe) semiconductive alloy is formed when a {111} crystal plane of a cubic diamond structure SiGe is grown on the {0001} C-plane of a single crystalline Al2O3 substrate such that a <110> orientation of the cubic diamond structure SiGe is aligned with a <1,0,-1,0> orientation of the {0001} C-plane. A lattice match between the substrate and the SiGe is achieved by using a SiGe composition that is 0.7223 atomic percent silicon and 0.2777 atomic percent germanium. A layer of Si(1-x), ,Ge(x) is formed on the cubic diamond structure SiGe. The value of X (i) defines an atomic percent of germanium satisfying 0.2277

  2. Disk-loaded RF waveguide matching techniques applied to silicon woodpile accelerator

    SciTech Connect

    Wu Ziran; England, Joel; Ng, Cho; Tantawi, Sami

    2012-12-21

    Silicon woodpile photonic crystal provides a three-dimensional dielectric waveguide system for high-gradient laser driven acceleration. The woodpile waveguide is periodically loaded in the longitudinal direction; therefore simple cross-sectional mode profile matching is not sufficient to launch the accelerating mode appropriately and will result in significant scattering loss. Hinted by the common nature of longitudinal periodicity between disk-loaded waveguide and woodpile waveguide, several coupler design schemes developed for multi-cell RF cavity are implemented in the woodpile accelerator design. Among them there are the travelling-wave match method based on S-matrix, the periodic VSWR method, and the TE-to-TM coupling iris design. This paper presents design procedures and simulation results using these methods. According to simulations, nearly 100% power transmission between SOI and woodpile waveguides with a travelling-wave match is achieved with a specially designed mode-launching coupler. Constructed by silicon rods extruding into the defect waveguide, the coupling iris provides necessary transition from TE mode to TM accelerating mode, also with negligible coupling loss.

  3. Energy Conversion Properties of ZnSiP2, a Lattice-Matched Material for Silicon-Based Tandem Photovoltaics

    SciTech Connect

    Martinez, Aaron D.; Warren, Emily L.; Gorai, Prashun; Borup, Kasper A.; Krishna, Lakshmi; Kuciauskas, Darius; Dippo, Patricia C.; Ortiz, Brenden R.; Stradins, Paul; Stevanovic, Vladan; Toberer, Eric S.; Tamboli, Adele C.

    2016-11-21

    ZnSiP2 demonstrates promising potential as an optically active material on silicon. There has been a longstanding need for wide band gap materials that can be integrated with Si for tandem photovoltaics and other optoelectronic applications. ZnSiP2 is an inexpensive, earth abundant, wide band gap material that is stable and lattice matched with silicon. This conference proceeding summarizes our PV-relevant work on bulk single crystal ZnSiP2, highlighting the key findings and laying the ground work for integration into Si-based tandem devices.

  4. Susceptibility of Geranium Cultivars (Pelargonium spp.) to Ralstonia solanacearum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sixty-one cultivars of geraniums including zonal, regal, ivy, and scented were tested for susceptibility to three strains of Ralstonia solanacearum: a Race 1 Biovar 1 (R1B1) strain P597 isolated from tomato in Florida, a R1B1 strain P673 obtained from pothos originating in Costa Rica, and a Race 3 B...

  5. Third harmonic generation from mid-IR to near-IR regions in a phase-matched silicon-silicon-nanocrystal hybrid plasmonic waveguide.

    PubMed

    Wu, Tingting; Shum, Perry Ping; Shao, Xuguang; Huang, Tianye; Sun, Yunxu

    2014-10-06

    The conversion efficiency of third harmonic generation (THG) from mid-IR (3600 nm) to near-IR (1200 nm) regions in a silicon-silicon-nanocrystal hybrid plasmonic waveguide (SSHPW) was calculated. The required modal phase-matching condition (PMC) between the 0-th mode at fundamental wave (FW) and the 2-nd mode at third harmonic (TH) is achieved by carefully designing the waveguide geometry. Benefiting from the hybridized surface plasmon polariton (SPP) nature of the two guided modes, the SSHPW is capable of achieving both high THG nonlinear coefficient |I₆| and reasonable linear propagation loss, thereby resulting in large figure-of-merits (FOMs) for both FW and TH. According to our simulation, THG conversion efficiency up to 0.823% is achieved at 62.9 ����m SSHPW with pump power of 1 W.

  6. The biological activities of cinnamon, geranium and lavender essential oils.

    PubMed

    Sienkiewicz, Monika; Głowacka, Anna; Kowalczyk, Edward; Wiktorowska-Owczarek, Anna; Jóźwiak-Bębenista, Marta; Łysakowska, Monika

    2014-12-12

    Acinetobacter sp. represent an important cause of nosocomial infections. Their resistance to some antibiotics, their ability to survive on inanimate surfaces in the hospital environment and their ability to produce biofilms contributes to their virulence. The aim of the study was to determine the antibacterial properties of cinnamon, lavender and geranium essential oils against bacteria of the genus Acinetobacter isolated from several clinical materials and from the hospital environment. A comprehensive evaluation of the susceptibility of Acinetobacter sp. clinical strains to recommended antibiotics was performed. The constituents of cinnamon, lavender and geranium essential oils were identified by GC-FID-MS analysis, and their Minimal Inhibitory Concentrations (MICs) against tested clinical strains were determined by the micro-dilution broth method. In addition, the effects of essential oils on the viability of human microvascular endothelial cells (HMEC-1) and glioblastoma cell line (T98G) were evaluated. Cinnamon bark oil was the most active against clinical and environmental strains of Acinetobacter baumannii with MIC values ranging from 0.5 to 2.5 µL/mL. The MIC values for geranium oil were between 7.5 and 9.5 µL/mL, and between 10.5 and 13.0 µL/mL for lavender oil. These essential oils can be best employed in the fight against infections caused by bacteria from Acinetobacter genus as components of formulations for hygiene and disinfection of hospital environment.

  7. Quasi-phase-matched second harmonic generation in silicon nitride ring resonators controlled by static electric field.

    PubMed

    de Oliveira, Rafael E P; de Matos, Christiano J S

    2013-12-30

    Actively-controlled second harmonic generation in a silicon nitride ring resonator is proposed and simulated. The ring was designed to resonate at both pump and second harmonic wavelengths and quasi-phase-matched frequency conversion is induced by a periodic static electric field generated by voltage applied to electrodes arranged along the ring. Nonlinear propagation simulations were undertaken and an efficiency of -21.67 dB was calculated for 60 mW of pump power at 1550 nm and for a 30V applied voltage, which compares favorably with demonstrated all-optical second harmonic generation in integrated microresonators. Transient effects were also evaluated. The proposed design can be exploited for the construction of electro-optical devices based on nonlinear effects in CMOS compatible circuits.

  8. Joining of silicon carbide using interlayer with matching coefficient of thermal expansion

    SciTech Connect

    Perham, T. |

    1996-11-01

    The primary objective of this study is to develop a technique for joining a commercially available Silicon Carbide that gives good room temperature strength and the potential for good high temperature strength. One secondary objective is that the joining technique be adaptable to SiC{sub f}/SiC composites and/or Nickel based superalloys, and another secondary objective is that the materials provide good neutron irradiation resistance and low activation for potential application inside nuclear fusion reactors. The joining techniques studied here are: (1) reaction bonding with Al-Si/Si/SiC/C; (2) reaction/infiltration with calcium aluminum silicate; (3) ion exchange mechanism to form calcium hexaluminate (a refractory cement); and (4) oxide frit brazing with cordierite.

  9. The Sensitivity of Endodontic Enterococcus spp. Strains to Geranium Essential Oil.

    PubMed

    Łysakowska, Monika E; Sienkiewicz, Monika; Banaszek, Katarzyna; Sokołowski, Jerzy

    2015-12-21

    Enterococci are able to survive endodontic procedures and contribute to the failure of endodontic therapy. Thus, it is essential to identify novel ways of eradicating them from infected root canals. One such approach may be the use of antimicrobials such as plant essential oils. Enterococcal strains were isolated from endodontically treated teeth by standard microbiological methods. Susceptibility to antibiotics was evaluated by the disc-diffusion method. The minimal inhibitory concentration (MIC) of geranium essential oil was investigated by microdilution in 96-well microplates in Mueller Hinton Broth II. Biofilm eradication concentrations were checked in dentin tests. Geranium essential oil inhibited enterococcal strains at concentrations ranging from 1.8-4.5 mg/mL. No correlation was shown between resistance to antibiotics and the MICs of the test antimicrobials. The MICs of the test oil were lower than those found to show cytotoxic effects on the HMEC-1 cell line. Geranium essential oil eradicated enterococcal biofilm at concentrations of 150 mg/mL. Geranium essential oil inhibits the growth of endodontic enterococcal species at lower concentrations than those required to reach IC50 against the HMEC-1 cell line, and is effective against bacteria protected in biofilm at higher concentrations. In addition, bacteria do not develop resistance to essential oils. Hence, geranium essential oil represents a possible alternative to other antimicrobials during endodontic procedures.

  10. Antioxidant effects of secondary metabolites from Geranium psilostemon.

    PubMed

    Söhretoğlu, Didem; Sabuncuoğlu, Suna Atasayar; Sakar, M Koray; Ozgüneş, Hilal; Sterner, Olov

    2010-06-01

    An investigation was made of the effects on endogenous antioxidant enzyme activities and H2O2-induced lipid peroxidation inhibition in human red blood cells of the crude MeOH extract and its EtOAc, n-BuOH, and H2O sub-extracts obtained from aerial parts of Geranium psilostemon Ledeb., as well as compounds isolated from the most active EtOAc extract. Gallic acid (1), methyl gallate (2), pusilagin (3), 1,3,6-tri-O-galloyl-beta-glucopyranoside (4), 1,2,3,4,6-penta-O-galloyl-beta-glucopyranoside (5), kaempferol (6), quercetin (7), kaempferol 7-O-alpha-rhamnopyranoside (8), and quercetin 7-O-alpha-rhamnopyranoside (9) were isolated from the aerial parts of the title plant, and their structures identified from spectroscopic (UV, 1D- and 2D- NMR) and spectrometric (TOF-MS) data. All extracts and isolated compounds inhibited H2O2-induced lipid peroxidation and also enhanced the activity of superoxide dismutase (SOD) and catalase (CAT).

  11. [Study on morphology of the pollen of 4 species from Geranium in Heilongjiang Province].

    PubMed

    Liu, Juan; Lu, Ye; Shen, Li

    2002-01-01

    Morphology of the pollen of 4 species from Geranium in Heilongjiang province which are G. wilfordii Maxim., G. sibiricum L., G. platyanthum Duthie. and G. dahuricum DC. were observed with optical microscope and scanning electron microscope. The results showed pollen grains of the four species were nearly spherical, with short clavate-shaped, net-shaped and cave-shaped veins on the outer walls and three short-furrow germ pores. Both the clava size and number of clava per unit surface area were different. This paper provided evidences for palynology classification of Geranium.

  12. A Rare Excitatory Amino Acid from Flowers of Zonal Geranium responsible for Paralyzing the Japanese Beetle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    e Japanese beetle (Popillia japonica) exhibits rapid paralysis after consuming flowers from zonal geranium (Pelargonium × hortorum). Activity-guided fractionations were conducted with polar flower petal extracts from Pelargonium × hortorum cv. Nittany Lion Red, which led to the isolation of a paraly...

  13. Iodine 125 Brachytherapy With Vitrectomy and Silicone Oil in the Treatment of Uveal Melanoma: 1-to-1 Matched Case-Control Series

    SciTech Connect

    McCannel, Tara A. McCannel, Colin A.

    2014-06-01

    Purpose: We initially reported the radiation-attenuating effect of silicone oil 1000 centistokes for iodine 125. The purpose of this report was to compare the clinical outcomes in case patients who had iodine 125 brachytherapy with vitrectomy and silicone oil 1000 centistokes with the outcomes in matched control patients who underwent brachytherapy alone. Methods and Materials: Consecutive patients with uveal melanoma who were treated with iodine 125 plaque brachytherapy and vitrectomy with silicone oil with minimum 1-year follow-up were included. Control patients who underwent brachytherapy alone were matched for tumor size, location, and sex. Baseline patient and tumor characteristics and tumor response to radiation, final visual acuity, macular status, central macular thickness by ocular coherence tomography (OCT), cataract progression, and metastasis at last follow-up visit were compared. Surgical complications were also determined. Results: Twenty case patients met the inclusion criteria. The average follow-up time was 22.1 months in case patients and 19.4 months in control patients. The final logMAR vision was 0.81 in case patients and 1.1 in control patients (P=.071); 8 case patients and 16 control patients had abnormal macular findings (P=.011); and the average central macular thickness by OCT was 293.2 μm in case patients and 408.5 μm in control patients (P=.016). Eleven case patients (55%) and 1 control patient (5%) had required cataract surgery at last follow-up (P=.002). Four patients in the case group and 1 patient in the control group experienced metastasis (P=.18). Among the cases, intraoperative retinal tear occurred in 3 patients; total serous retinal detachment and macular hole developed in 1 case patient each. There was no case of rhegmatogenous retinal detachment, treatment failure, or local tumor dissemination in case patients or control patients. Conclusions: With up to 3 years of clinical follow-up, silicone oil during brachytherapy

  14. Engineering of phase matching for mid-infrared coherent anti-Stokes Raman wavelength conversion with orthogonally polarized pump and Stokes waves in silicon-on-sapphire waveguides.

    PubMed

    Wang, Zhaolu; Liu, Hongjun; Huang, Nan; Sun, Qibing; Li, Xuefeng

    2013-11-20

    The conversion efficiency of mid-infrared wavelength conversion based on coherent anti-Stokes Raman scattering with TE-polarized pump and TM-polarized Stokes waves is theoretically investigated in silicon-on-sapphire (SOS) waveguides. The peak conversion efficiency of -10  dB is obtained when the linear propagation loss is 1  dB/cm at Δk=0; however, it is reduced to -13.6  dB when the linear propagation loss is 2  dB/cm. The phase matching for wavelength conversion with orthogonally polarized pump and Stokes waves can be realized by engineering the birefringence in SOS waveguides, because proper phase mismatch induced by birefringence together with material dispersion-induced phase mismatch can counteract the large phase mismatch induced by waveguide dispersion. Moreover, compared with the phase matching for identically polarized pump and Stokes waves, the phase matching for orthogonally polarized pump and Stokes waves can be realized in a SOS waveguide with much smaller cross section, which reduces the power requirement for optical systems.

  15. Lethal activity of individual and mixed monoterpenoids of geranium essential oil on Musca domestica.

    PubMed

    Gallardo, Anabella; Picollo, María Inés; Mougabure-Cueto, Gastón

    2015-03-01

    Plant essential oils and its constituent molecules have been suggested as an alternative to control insect. The contribution of the constituents to the effect of the oil is determined by the interactions occurring between them. Synergistic interactions would improve the insecticide efficacy of the compounds due to the utilization of lower doses. We evaluated the insecticidal activity of geranium (Geranium maculatum L.) oil and its major constituents against Musca domestica L. and studied the toxic interactions in artificial mixtures of those constituents in the natural ratio. While synergistic interactions were determined in house fly in this study, these were of low intensity evidencing that the effect of each constituent was slightly modified by the other constituents present in the mixtures. The search for synergism between components is a strategy to improve the insecticide activity of natural compounds. The synergism helps to reduce the environmental and toxicological impact due to the reduction of the dose of use.

  16. A distribution and taxonomic reference dataset of Geranium in the New World.

    PubMed

    Aedo, Carlos; Pando, Francisco

    2017-04-11

    Geranium L. is a genus of over 350 species distributed throughout most of the world, except in lowland tropical areas. It is the largest genus of the Geraniaceae and is represented in the New World by 137 species. This dataset includes 8,937 records that covers the genus Geranium the New World, providing an updated, taxonomically consistent and a sound geographical distribution of the 137 species of Geranium in America. Specimens from 128 herbaria were reviewed. These were supplemented by others collected during nine field trips, which allowed better knowledge of the variability of characters within populations, and refining species distribution ranges. Each record represents a specimen that has been reviewed and in some cases collected by C. Aedo. Accepted scientific name, locality details, distribution status (introduced, native, naturalized, uncertain), geographic coordinates are given for 8,538 (95%) records, and habitat information for 3,952 (44%). All data have been released under a CC-BY license in a standardized format, which enables easy integration with other data, for example through GBIF.org.

  17. Performance of rose scented geranium (Pelargonium graveolens) in heavy metal polluted soil vis-à-vis phytoaccumulation of metals.

    PubMed

    Chand, Sukhmal; Singh, Geetu; Patra, D D

    2016-08-02

    An investigation was carried out to evaluate the effect of heavy metal toxicity on growth, herb, oil yield and quality and metal accumulation in rose scented geranium (Pelargonium graveolens) grown in heavy metal enriched soils. Four heavy metals (Cd, Ni, Cr, and Pb) each at two levels (10 and 20 mg kg-1 soil) were tested on geranium. Results indicated that Cr concentration in soil at 20 mg kg-1 reduced leaves, stem and root yield by 70, 83, and 45%, respectively, over control. Root growth was significantly affected in Cr stressed soil. Nickel, Cr, and Cd concentration and accumulation in plant increased with higher application of these metals. Chromium, nickel and cadmium uptake was observed to be higher in leaves than in stem and roots. Essential oil constituents were generally not significantly affected by heavy metals except Pb at 10 and 20 ppm, which significantly increased the content of citronellol and Ni at 20 ppm increased the content of geraniol. Looking in to the higher accumulation of toxic metals by geranium and the minimal impact of heavy metals on quality of essential oil, geranium can be commercially cultivated in heavy metal polluted soil for production of high value essential oil.

  18. Fertilization and Colors of Plastic Mulch Affect Biomass and Essential Oil of Sweet-Scented Geranium

    PubMed Central

    Silva, Anderson de Carvalho; dos Santos, Wallace Melo; Prata, Paloma Santana; Alves, Péricles Barreto

    2014-01-01

    Sweet-scented geranium (Pelargonium graveolens L'Hér), a plant belonging to the Geraniaceae family, has medicinal and aromatic properties and is widely used in the cosmetic, soap, perfume, aromatherapy, and food industries. The aim of this study was to evaluate the influence of fertilization and the use of different colors of plastic mulch on sweet-scented geranium biomass and essential oil. Three colors of plastic mulch (black, white, and silver-colored) and a control without plastic mulch were assessed along with three fertilizers (20,000 L·ha−1 of cattle manure; 1,000 kg·ha−1 of NPK 3-12-6; and 20,000 L·ha−1 of cattle manure + 1,000 kg·ha−1 of NPK 3-12-6 fertilizer) and a control without fertilizer. The absence of a soil cover negatively influenced the agronomical variables, while coverage with plastic mulch was associated with increased biomass. The use of fertilizer had no effect on the evaluated agronomic variables. When cattle manure and NPK 3-12-6 were used together, combined with white or black plastic mulch, the highest yields of essential oil were obtained. For the silver-colored plastic mulch, higher amounts of essential oil (6,9-guaiadien) were obtained with mineral fertilizer. PMID:24757440

  19. Fertilization and colors of plastic mulch affect biomass and essential oil of sweet-scented geranium.

    PubMed

    Silva, Anderson de Carvalho; Blank, Arie Fitzgerald; dos Santos, Wallace Melo; Prata, Paloma Santana; Alves, Péricles Barreto; Arrigoni-Blank, Maria de Fátima

    2014-01-01

    Sweet-scented geranium (Pelargonium graveolens L'Hér), a plant belonging to the Geraniaceae family, has medicinal and aromatic properties and is widely used in the cosmetic, soap, perfume, aromatherapy, and food industries. The aim of this study was to evaluate the influence of fertilization and the use of different colors of plastic mulch on sweet-scented geranium biomass and essential oil. Three colors of plastic mulch (black, white, and silver-colored) and a control without plastic mulch were assessed along with three fertilizers (20,000 L · ha(-1) of cattle manure; 1,000 kg · ha(-1) of NPK 3-12-6; and 20,000 L · ha(-1) of cattle manure + 1,000 kg · ha(-1) of NPK 3-12-6 fertilizer) and a control without fertilizer. The absence of a soil cover negatively influenced the agronomical variables, while coverage with plastic mulch was associated with increased biomass. The use of fertilizer had no effect on the evaluated agronomic variables. When cattle manure and NPK 3-12-6 were used together, combined with white or black plastic mulch, the highest yields of essential oil were obtained. For the silver-colored plastic mulch, higher amounts of essential oil (6,9-guaiadien) were obtained with mineral fertilizer.

  20. Influence of an organic mulching on fertilizer nitrogen use efficiency and herb and essential oil yields in geranium (Pelargonium graveolens).

    PubMed

    Ram, Muni; Ram, D; Roy, S K

    2003-05-01

    In a field study, conducted at Lucknow ( 26.5 degrees N, 80.5 degrees E and 120 m altitude), India for two years (1996-1997 and 1997-1998), eight treatment combinations of two variables of organic mulch (paddy straw at 7 t/ha and no mulch) and four levels of fertilizer nitrogen (0, 80, 160 and 240 kg/ha) were examined to observe the effect of organic mulching on N-use efficiency and essential oil yield in a multi-harvested geranium crop. Results revealed that application of paddy straw mulch increased the herb and essential oil yields in geranium by 23% and 27%, respectively, over the unmulched control at planted crop harvest. Corresponding values at regenerated crop harvest were 18.7% and 19.2%. A significant response to N was observed with 160 kgN/ha in mulched plot over the same level of N in the unmulched plot. Using paddy straw mulch, nitrogen uptake by plants of planted and regenerated crops was increased by 33% and 28.4%, respectively, over the unmulched control. Apparent N recoveries by planted and regenerated crops were estimated to be 33.7% and 22.7% for the unmulched control, as against 40% and 29.2% with paddy straw mulch at 160 kgN/ha. The quality of essential oil of geranium in terms of its major constituents, citronellol and geraniol, was not affected by the use of organic mulching and nitrogen fertilization and these constituents were found to be of a standard acceptable in international trade. It was concluded from this study that use of an organic mulch with 160 kgN/ha proved better in terms of economising 80 kgN/ha to produce an economic yield of 96.1 kg geranium oil from two harvests under subtropical conditions of the north Indian plains. At 160 kgN/ha, paddy straw mulch application permitted the geranium crop to produce 18.4 kg/ha more oil which gave an additional return of Rs. 53,600/ha than that of unmulched control. Paddy straw mulch and nitrogen fertilization had no adverse effect on the quality of essential oil of geranium.

  1. [Optimization of extraction process for tannins from Geranium orientali-tibeticum by supercritical CO2 method].

    PubMed

    Xie, Song; Tong, Zhi-Ping; Tan, Rui; Liu, Xiao-Zhen

    2014-08-01

    In order to optimize extraction process conditions of tannins from Geranium orientali-tibeticum by supercritical CO2, the content of tannins was determined by phosphomolybdium tungsten acid-casein reaction, with extraction pressure, extraction temper- ature and extraction time as factors, the content of tannins from extract of G. orientali-tibeticum as index, technology conditions were optimized by orthogonal test. Optimum technology conditions were as follows: extraction pressure was 25 MPa, extraction temperature was 50 °C, extracted 1.5 h. The content of tannins in extract was 12.91 mg x g(-1), extract rate was 3.67%. The method established could be used for assay the contents of tannin in G. orientali-tibeticum. The circulated extraction was an effective extraction process that was stable and feasible, and that provides a way of the extraction process conditions of tannin from G. orientali-tibeticum.

  2. A somaclonal variant of rose-scented geranium (Pelargonium spp.) with moderately high content of isomenthone in its essential oil.

    PubMed

    Kulkarni, Swaroop S; Ravindra, Nagawara S; Srinivas, Kalavagunta V N S; Kulkarni, Raghavendra N

    2012-09-01

    Rose-scented geranium (Pelargonium spp.), which is highly valued for its essential oil, is exclusively propagated vegetatively. Hence no genetic improvement work is possible through conventional breeding. Somaclonal variation was generated with and without in vitro mutagenesis using N-nitroso-N-methyl urea (NMU) in an Indian cultivar 'Bourbon', and a clone 'Narmada'. A somaclonal variant (N75) with a moderately high content of isomenthone in its essential oil was isolated from somaclones generated after treatment of internodal explants of clone, 'Narmada' with 0.25 mM NMU for 1 h. The contents of isomenthone in its essential oil were 26% and 35%, respectively, in SC2/VM2 and SC3/VM3 generations (second and third vegetative generations, respectively, after in vitro mutagen treatment) as compared with 0.7% and 0.3%, respectively, in the parental clone, 'Narmada'. The contents of alcohols and their esters (linalool, citronellol, geraniol, citronellyl formate and geranyl formate) in the essential oil of N75 in SC2/VM2 and SC3/VM3 generations were 49% and 35%, respectively, as compared with 69% and 63%, respectively, in the parental clone, 'Narmada'. This is the first report on a chemovariant of rose-scented geranium with a moderately high content of isomenthone. All earlier reported isomenthone-rich variants of rose-scented geranium had quite high contents of isomenthone (64-71%) in their essential oils. The probable modes of origin of this somaclonal variant, its parental clone 'Narmada' (with very low content of isomenthone) and four earlier reported isomenthone-rich variants of Indian cultivars of geranium are discussed.

  3. Anti-inflammatory effect of geranium nanoemulsion macrophages induced with soluble protein of Candida albicans.

    PubMed

    Giongo, Janice Luehring; de Almeida Vaucher, Rodrigo; Sagrillo, Michele; Vianna Santos, Roberto Christ; Duarte, Marta M M F; Rech, Vírginia Cielo; Soares Lopes, Leonardo Quintana; Beatriz da Cruz, Ivana; Tatsch, Etiane; Moresco, Rafael Noal; Gomes, Patricia; Steppe, Martin

    2017-01-31

    Pelargonium graveolens is a member of the Geraniaceae family and has been used in folk medicine in many countries because of its anti-inflammatory activity. No studies have yet been reported to evaluate the anti-inflammatory activity of a nanoemulsion containing geranium oil (GO) model in macrophages. In this study the anti-inflammatory effect of Geranium nanoemulsion (NEG) macrophages induced with soluble proteins of Candida albicans was investigated. GO presented citronellol (17.74%) and geraniol (14.43%) as main constituents. The characterization in NEG was demonstrated, showing the particle size of 164 ± 3.5 nm, PDI of 0.12 ± 0.006 and zeta potential -10 mV ± 1.7. The MIC obtained for NEG and GO were 3.64 μg ml(-1) and 1.82 μg ml(-1), respectively. The viability of the macrophages treated with NEG and GO concentrations (1/2 x, 1x and 2x MIC) was evaluated. There was a significant reduction of viability and the MTT assay was not confirmed after the LDH assay. Anti-inflammatory activity was evaluated by determining nitric oxide (NO), cytokines (interleukin IL-1, IL-6 and IL-10), tumor necrosis factor-α (TNF) and the expression levels gene of interleukin (IL-2), cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). The apoptosis inhibition capacity was assessed by determination of INFγ, caspase 3 and caspase 8. The results indicated that there was a significant increase of NO in the levels after treatment with NEG and significantly reduced levels after treatment with GO. The cytokines (IL-1, IL-6, IL-10, and TNF) were evaluated and NEG (½ x, 1x MIC) decreased IL-1 levels by 1.25-1.37 times, respectively. The NEG did not decrease IL-6 levels and a significant increase was observed for IL-10. GO significantly decreased IL-6 and IL-10 levels. There was a significant decrease in IL-2 and COX-2 levels and increased levels of iNOs. The levels of IFNγ and caspase-3 after treatment with NEG decreased indicating an anti

  4. Rose geranium essential oil as a source of new and safe anti-inflammatory drugs

    PubMed Central

    Boukhatem, Mohamed Nadjib; Kameli, Abdelkrim; Ferhat, Mohamed Amine; Saidi, Fairouz; Mekarnia, Maamar

    2013-01-01

    Background Since the available anti-inflammatory drugs exert an extensive variety of side effects, the search for new anti-inflammatory agents has been a priority of pharmaceutical industries. Aims The aim of the present study was to assess the anti-inflammatory activities of the essential oil of rose geranium (RGEO). Methods The chemical composition of the RGEO was investigated by gas chromatography. The major components were citronellol (29.13%), geraniol (12.62%), and citronellyl formate (8.06%). In the carrageenan-induced paw edema, five different groups were established and RGEO was administered orally in three different doses. Results RGEO (100 mg/kg) was able to significantly reduce the paw edema with a comparable effect to that observed with diclofenac, the positive control. In addition, RGEO showed a potent anti-inflammatory activity by topical treatment in the method of croton oil-induced ear edema. When the dose was 5 or 10 µl of RGEO per ear, the inflammation was reduced by 73 and 88%, respectively. This is the first report to demonstrate a significant anti-inflammatory activity of Algerian RGEO. In addition, histological analysis confirmed that RGEO inhibited the inflammatory responses in the skin. Conclusion Our results indicate that RGEO may have significant potential for the development of novel anti-inflammatory drugs with improved safety profile. PMID:24103319

  5. Rose geranium essential oil as a source of new and safe anti-inflammatory drugs.

    PubMed

    Nadjib Boukhatem, Mohamed; Kameli, Abdelkrim; Amine Ferhat, Mohamed; Saidi, Fairouz; Mekarnia, Maamar

    2013-01-01

    Background Since the available anti-inflammatory drugs exert an extensive variety of side effects, the search for new anti-inflammatory agents has been a priority of pharmaceutical industries. Aims The aim of the present study was to assess the anti-inflammatory activities of the essential oil of rose geranium (RGEO). Methods The chemical composition of the RGEO was investigated by gas chromatography. The major components were citronellol (29.13%), geraniol (12.62%), and citronellyl formate (8.06%). In the carrageenan-induced paw edema, five different groups were established and RGEO was administered orally in three different doses. Results RGEO (100 mg/kg) was able to significantly reduce the paw edema with a comparable effect to that observed with diclofenac, the positive control. In addition, RGEO showed a potent anti-inflammatory activity by topical treatment in the method of croton oil-induced ear edema. When the dose was 5 or 10 µl of RGEO per ear, the inflammation was reduced by 73 and 88%, respectively. This is the first report to demonstrate a significant anti-inflammatory activity of Algerian RGEO. In addition, histological analysis confirmed that RGEO inhibited the inflammatory responses in the skin. Conclusion Our results indicate that RGEO may have significant potential for the development of novel anti-inflammatory drugs with improved safety profile.

  6. Nectar Sugar Production across Floral Phases in the Gynodioecious Protandrous Plant Geranium sylvaticum

    PubMed Central

    Varga, Sandra; Nuortila, Carolin; Kytöviita, Minna-Maarit

    2013-01-01

    Many zoophilous plants attract their pollinators by offering nectar as a reward. In gynodioecious plants (i.e. populations are composed of female and hermaphrodite individuals) nectar production has been repeatedly reported to be larger in hermaphrodite compared to female flowers even though nectar production across the different floral phases in dichogamous plants (i.e. plants with time separation of pollen dispersal and stigma receptivity) has rarely been examined. In this study, sugar production in nectar standing crop and secretion rate were investigated in Geranium sylvaticum, a gynodioecious plant species with protandry (i.e. with hermaphrodite flowers releasing their pollen before the stigma is receptive). We found that flowers from hermaphrodites produced more nectar than female flowers in terms of total nectar sugar content. In addition, differences in nectar production among floral phases were found in hermaphrodite flowers but not in female flowers. In hermaphrodite flowers, maximum sugar content coincided with pollen presentation and declined slightly towards the female phase, indicating nectar reabsorption, whereas in female flowers sugar content did not differ between the floral phases. These differences in floral reward are discussed in relation to visitation patterns by pollinators and seed production in this species. PMID:23614053

  7. Sylvatiins, acetylglucosylated hydrolysable tannins from the petals of Geranium sylvaticum show co-pigment effect.

    PubMed

    Tuominen, Anu; Sinkkonen, Jari; Karonen, Maarit; Salminen, Juha-Pekka

    2015-07-01

    Four hydrolysable tannins, named as sylvatiins A (1), B (2), C (3) and D (4), were isolated from the petals of Geranium sylvaticum. On the basis of spectrometric evidence of NMR analysis ((1)H NMR, (13)C NMR, DQF-COSY, TOCSY, NOESY, HSQC and HMBC), circular dichroism (CD) and ESI-MS/MS, sylvatiins A, B and C were characterized as galloyl glucoses containing one or two acetylglucoses attached to the 3-OH of the galloyl group, whereas sylvatiin D was found to have a chebulinic acid core containing acetylglucose attached in a similar way. The potential of these compounds to act as defensive compounds against herbivores was evaluated using the radial diffusion assay that measures the protein precipitation capacity. In addition, the capacity of sylvatiins to act as co-pigments with anthocyanins of G. sylvaticum petals was measured in vitro at different pH values. Sylvatiins A and D maintained efficiently the purple flower color near the natural pH of petal cells. The amount of sylvatiins was changed according to the flower color; deep purple petals with higher amount of anthocyanin contained more sylvatiins A and C than whiter petals. It was concluded that G. sylvaticum petal cells may accumulate sylvatiins for intermolecular co-pigmentation purposes.

  8. Over-expression of DXS gene enhances terpenoidal secondary metabolite accumulation in rose-scented geranium and Withania somnifera: active involvement of plastid isoprenogenic pathway in their biosynthesis.

    PubMed

    Jadaun, Jyoti Singh; Sangwan, Neelam S; Narnoliya, Lokesh K; Singh, Neha; Bansal, Shilpi; Mishra, Bhawana; Sangwan, Rajender Singh

    2017-04-01

    Rose-scented geranium (Pelargonium spp.) is one of the most important aromatic plants and is well known for its diverse perfumery uses. Its economic importance is due to presence of fragrance rich essential oil in its foliage. The essential oil is a mixture of various volatile phytochemicals which are mainly terpenes (isoprenoids) in nature. In this study, on the geranium foliage genes related to isoprenoid biosynthesis (DXS, DXR and HMGR) were isolated, cloned and confirmed by sequencing. Further, the first gene of 2-C-methyl-d-erythritol-4-phosphate (MEP) pathway, 1-deoxy-d-xylulose-5-phosphate synthase (GrDXS), was made full length by using rapid amplification of cDNA ends strategy. GrDXS contained a 2157 bp open reading frame that encoded a polypeptide of 792 amino acids having calculated molecular weight 77.5 kDa. This study is first report on heterologous expression and kinetic characterization of any gene from this economically important plant. Expression analysis of these genes was performed in different tissues as well as at different developmental stages of leaves. In response to external elicitors, such as methyl jasmonate, salicylic acid, light and wounding, all the three genes showed differential expression profiles. Further GrDXS was over expressed in the homologous (rose-scented geranium) as well as in heterologous (Withania somnifera) plant systems through genetic transformation approach. The over-expression of GrDXS led to enhanced secondary metabolites production (i.e. essential oil in rose-scented geranium and withanolides in W. somnifera). To the best of our knowledge, this is the first report showing the expression profile of the three genes related to isoprenoid biosynthesis pathways operated in rose-scented geranium as well as functional characterization study of any gene from rose-scented geranium through a genetic transformation system.

  9. Effect of Variable Solvents on Particle Size of Geranium Oil-Loaded Solid Lipid Nanoparticle (Ge-SLN) For Mosquito Repellent Applications

    NASA Astrophysics Data System (ADS)

    Asnawi, Syalwati; Aziz, Azila A.; Aziz, Ramlan A.

    2009-06-01

    A new delivery system for insect repellent is proposed by the incorporation of geranium oil into solid lipid nanoparticle (SLN). A variety of solvents which act as co-surfactants, were introduced to increase the particle size of GE-SLN. Ethanol, which has a high boiling point and a long chain alcohol produced larger particle than dichloromethane. The structure of SLN was not stable when methanol and acetone were used as co-solvents. Concentration of solvents can also influence the size of SLN. In vitro release experiments showed that SLN was able to reduce the rapid evaporation of geranium oil.

  10. Changes in leaf water relations, gas exchange, growth and flowering quality in potted geranium plants irrigated with different water regimes.

    PubMed

    Sánchez-Blanco, Ma Jesús; Alvarez, Sara; Navarro, Alejandra; Bañón, Sebastián

    2009-03-15

    Geranium plants are an important part of urban green areas but suffer from drought, especially when grown in containers with a limited volume of medium. In this experiment, we examined the response of potted geraniums to different irrigation levels. Geranium (Pelargoniumxhortorum L.) seedlings were grown in a growth chamber and exposed to three irrigation treatments, whereby the plants were irrigated to container capacity (control), 60% of the control (moderate deficit irrigation, MDI), or 40% of the control (severe deficit irrigation, SDI). Deficit irrigation was maintained for 2 months, and then all the plants were exposed to a recovery period of 112 month. Exposure to drought induced a decrease in shoot dry weight and leaf area and an increase in the root/shoot ratio. Height and plant width were significantly inhibited by the SDI, while flower color parameters were not affected by deficit treatment. The number of wilting and yellow leaves increased, coinciding with the increase in the number of inflorescences and open flowers. Deficit irrigation led to a leaf water potential of about -0.8MPa at midday, which could have caused an important decrease in stomatal conductance, affecting the photosynthetic rate (Pn). Chlorophyll fluorescence (Fvm) values of 0.80 in all treatments throughout the experiment demonstrate the lack of drought-induced damage to PSII photochemistry. Pressure-volume analysis revealed low osmotic adjustment values of 0.2MPa in the SDI treatment, accompanied by increases in the bulk tissue elastic modulus (epsilon, wall rigidity) and resulting in turgor loss at lower leaf water potential values (-1.38MPa compared with -1.0MPa for the control). Leaf water potential values throughout the experiment below those for Psitlp were not found at any sampling time. By the end of the recovery period, the leaf water potential, stomatal conductance and net photosynthesis had recovered. We infer from these results that moderate deficit irrigation in geranium

  11. Hepatoprotective effect of Geranium schiedeanum against ethanol toxicity during liver regeneration

    PubMed Central

    Madrigal-Santillán, Eduardo; Bautista, Mirandeli; Gayosso-De-Lucio, Juan A; Reyes-Rosales, Yadira; Posadas-Mondragón, Araceli; Morales-González, Ángel; Soriano-Ursúa, Marvin A; García-Machorro, Jazmín; Madrigal-Bujaidar, Eduardo; Álvarez-González, Isela; Morales-González, José A

    2015-01-01

    AIM: To evaluate the effect of an extract of Geranium schiedeanum (Gs) as a hepatoprotective agent against ethanol (EtOH)-induced toxicity in rats. METHODS: Male Wistar rats weighing 200-230 g were subjected to a 70% partial hepatectomy (PH); they were then divided into three groups (groups 1-3). During the experiment, animals in group 1 drank only water. The other two groups (2-3) drank an aqueous solution of EtOH (40%, v/v). Additionally, rats in group 3 received a Gs extract daily at a dose of 300 mg/kg body weight intragastically. Subsequently, to identify markers of liver damage in serum, alanine aminotransferase, aspartate aminotransferase, albumin and bilirubin were measured by colorimetric methods. Glucose, triglyceride and cholesterol concentrations were also determined. In addition, oxidative damage was estimated by measuring lipid peroxidation [using thiobarbituric-acid reactive substances (TBARS)] in both plasma and the liver and by measuring the total concentration of antioxidants in serum and the total antioxidant capacity in the liver. In addition, a liver mass gain assessment, total DNA analysis and a morpho-histological analysis of the liver from animals in all three groups were performed and compared. Finally, the number of deaths observed in the three groups was analyzed. RESULTS: Administration of the Geranium shiedeanum extract significantly reduced the unfavorable effect of ethanol on liver regeneration (restitution liver mass: PH-EtOH group 60.68% vs PH-Gs-EtOH group 69.22%). This finding was congruent with the reduced levels of hepatic enzymes and the sustained or increased levels of albumin and decreased bilirubin in serum. The extract also modified the metabolic processes that regulate glucose and lipid levels, as observed from the serum measurements. Lower antioxidant levels and the liver damage induced by EtOH administration appeared to be mitigated by the extract, as observed from the TBARs (PH-EtOH group 200.14 mmol/mg vs PH

  12. Frequency-dependent pollinator discrimination acts against female plants in the gynodioecious Geranium maculatum

    PubMed Central

    Van Etten, Megan L.; Chang, Shu-Mei

    2014-01-01

    Background and Aims Gynodioecy, the co-occurrence of female and hermaphroditic individuals, is thought to be an intermediate step between hermaphroditism and separate sexes, a major transition in flowering plants. Because retaining females in a population requires that they have increased seed fitness (to compensate for the lack of pollen fitness), factors that affect seed fitness are of great importance to the evolution of this mating system and have often been studied. However, factors negatively affecting female fitness are equally important and have been largely neglected. One such factor stems from female flowers being less attractive to insects than hermaphrodite flowers, thereby decreasing their relative fitness. Methods To test the severity and consequences of this type of pollinator discrimination in Geranium maculatum, experimental populations with the range of sex ratios observed in nature were created, ranging from 13 % to 42 % females. Pollinators were observed in order to measure the strength of discrimination, and pollen deposition and seed production of both sexes were measured to determine the fitness consequences of this discrimination. Additionally a comparison was made across the sex ratios to determine whether discrimination was frequency-dependent. Key Results It was found that female flowers, on average, were visited at half of the rate of hermaphrodite flowers, which decreased their pollen receipt and seed production. Additionally, females were most discriminated against when rare, due to both changes in the pollinators' behaviour and a shift in pollinator composition. Conclusions The results suggest that pollinator discrimination negatively affects females' relative fitness when they are rare. Thus, the initial spread of females in a population, the first step in the evolution of gynodioecy, may be made more difficult due to pollinator discrimination. PMID:25326647

  13. Insecticidal and biting deterrent activity of rose-scented geranium (Pelargonium spp.) essential oils and individual compounds against Stephanitis pyrioides and Aedes aegypti

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rose-scented geranium, Pelargonium spp., essential oils from the cultivars ‘Bourbon’, ‘China’, ‘Egypt’ and cultivars ‘Rober’s Lemon Rose’ and ‘Frensham’ from South Carolina were analyzed by GC-FID and GC-MS. One-hundred and thirty six compounds were identified from five essential oils, which constit...

  14. Insecticidal activity of individual and mixed monoterpenoids of geranium essential oil against Pediculus humanus capitis (Phthiraptera: Pediculidae).

    PubMed

    Gallardo, A; Picollo, M I; González-Audino, P; Mougabure-Cueto, G

    2012-03-01

    The major components of geranium (Geranium maculatum L.) oil and their mixtures were tested against female Pediculus humanus capitis De Geer (Phthiraptera: Pediculidae). Chemical analysis by gas chromatography coupled to mass spectrometry revealed four major constituents: citronellol (38%), geraniol (16%), citronellyl formate (10.4%), and linalool (6.45%) (concentration expressed as percentage of total). Topical application demonstrated that the most potent component was citronellol and geraniol, with LD50 values 9.7 and 12.7 microg/insect, respectively. Linalool and Citronellyl formate were less toxic with LD50 values 24.7 and 38.5 microg/insect, respectively. Toxicity of these four major constituents in the same proportion as the natural oil, was greater than whole oil and each individual component. Removal of any four constituents produced a decreased in effectiveness. The absence of citronellol caused the greatest decrease in toxicity (DL50 from 2.2 to 10.9 microg/insect), leading us to conclude that this constituent is the major contributor to oil toxicity. The knowledge of the role of each constituent in the toxicity of the whole oil gives the possibility to create artificial blends of different constituents for the development of more effective control agents.

  15. Periodically poled silicon

    NASA Astrophysics Data System (ADS)

    Hon, Nick K.; Tsia, Kevin K.; Solli, Daniel R.; Jalali, Bahram

    2009-03-01

    We propose a new class of photonic devices based on periodic stress fields in silicon that enable second-order nonlinearity as well as quasi-phase matching. Periodically poled silicon (PePSi) adds the periodic poling capability to silicon photonics and allows the excellent crystal quality and advanced manufacturing capabilities of silicon to be harnessed for devices based on second-order nonlinear effects. As an example of the utility of the PePSi technology, we present simulations showing that midwave infrared radiation can be efficiently generated through difference frequency generation from near-infrared with a conversion efficiency of 50%.

  16. Defensive strategies in Geranium sylvaticum. Part 1: organ-specific distribution of water-soluble tannins, flavonoids and phenolic acids.

    PubMed

    Tuominen, Anu; Toivonen, Eija; Mutikainen, Pia; Salminen, Juha-Pekka

    2013-11-01

    A combination of high-resolution mass spectrometry and modern HPLC column technology, assisted by diode array detection, was used for accurate characterization of water-soluble polyphenolic compounds in the pistils, stamens, petals, sepals, stems, leaves, roots and seeds of Geranium sylvaticum. The organs contained a large variety of polyphenols, five types of tannins (ellagitannins, proanthocyanidins, gallotannins, galloyl glucoses and galloyl quinic acids) as well as flavonoids and simple phenolic acids. In all, 59 compounds were identified. Geraniin and other ellagitannins dominated in all the green photosynthetic organs. The other organs seem to produce distinctive polyphenol groups: pistils accumulated gallotannins; petals acetylglucose derivatives of galloylglucoses; stamens kaempferol glycosides, and seeds and roots accumulated proanthocyanidins. The intra-plant distribution of the different polyphenol groups may reflect the different functions and importance of various types of tannins as the defensive chemicals against herbivory.

  17. Inhibitory effects of geranium essential oil and its major component, citronellol, on degranulation and cytokine production by mast cells.

    PubMed

    Kobayashi, Yuko; Sato, Harumi; Yorita, Mika; Nakayama, Hiroto; Miyazato, Hironari; Sugimoto, Keiichiro; Jippo, Tomoko

    2016-06-01

    We investigated the effects of geranium essential oil (GEO) on anaphylaxis. GEO can exert antioxidant and anti-inflammatory effects, but its roles in allergic reactions are incompletely understood. Here, we used mouse cells to show that GEO inhibited the degranulation of cultured mast cells (CMCs). Citronellol is the major component of GEO and inhibited CMC degranulation. The l-enantiomer of citronellol more effectively suppressed CMC degranulation than did d-citronellol. We also examined whether citronellol could inhibit the immunoglobulin (Ig) E-induced production of tumor necrosis factor (TNF)-α. Treatment with various concentrations of citronellol before CMC activation with IgE significantly inhibited the induction of TNF-α in a dose-dependent manner. Mechanistically, citronellol suppressed the phosphorylation of mitogen-activated protein kinase (ERK), which is critical for ERK activation and the production of inflammatory cytokines in mast cells. These findings suggest that citronellol may represent a candidate compound for the effective treatment of allergic diseases.

  18. Biophysical studies of interaction between hydrolysable tannins isolated from Oenothera gigas and Geranium sanguineum with human serum albumin.

    PubMed

    Sekowski, Szymon; Ionov, Maksim; Kaszuba, Mateusz; Mavlyanov, Saidmukhtar; Bryszewska, Maria; Zamaraeva, Maria

    2014-11-01

    Tannins, secondary plant metabolites, possess diverse biological activities and can interact with biopolymers such as lipids or proteins. Interactions between tannins and proteins depend on the structures of both and can result in changes in protein structure and activity. Because human serum albumin is the most abundant protein in plasma and responsible for interactions with important biological compounds (e.g. bilirubin) and proper blood pressure, therefore, it is very important to investigate reactions between HSA and tannins. This paper describes the interaction between human serum albumin (HSA) and two tannins: bihexahydroxydiphenoyl-trigalloylglucose (BDTG) and 1-O-galloyl-4,6-hexahydroxydiphenoyl-β-d-glucose (OGβDG), isolated from Geranium sanguineum and Oenothera gigas leafs, respectively. Optical (spectrofluorimetric) and chiral optical (circular dichroism) methods were used in this study. Fluorescence analysis demonstrated that OGβDG quenched HSA fluorescence more strongly than BDTG. Both OGβDG and BDTG formed complexes with albumin and caused a red shift of the fluorescence spectra but did not significantly change the protein secondary structure. Our studies clearly demonstrate that the tested tannins interact very strongly with human serum albumin (quenching constant K=88,277.26±407.04 M(-1) and K=55,552.67±583.07 M(-1) respectively for OGβDG and BDTG) in a manner depending on their chemical structure.

  19. Periodically poled silicon

    NASA Astrophysics Data System (ADS)

    Hon, Nick K.; Tsia, Kevin K.; Solli, Daniel R.; Khurgin, Jacob B.; Jalali, Bahram

    2010-02-01

    Bulk centrosymmetric silicon lacks second-order optical nonlinearity χ(2) - a foundational component of nonlinear optics. Here, we propose a new class of photonic device which enables χ(2) as well as quasi-phase matching based on periodic stress fields in silicon - periodically-poled silicon (PePSi). This concept adds the periodic poling capability to silicon photonics, and allows the excellent crystal quality and advanced manufacturing capabilities of silicon to be harnessed for devices based on χ(2)) effects. The concept can also be simply achieved by having periodic arrangement of stressed thin films along a silicon waveguide. As an example of the utility, we present simulations showing that mid-wave infrared radiation can be efficiently generated through difference frequency generation from near-infrared with a conversion efficiency of 50% based on χ(2) values measurements for strained silicon reported in the literature [Jacobson et al. Nature 441, 199 (2006)]. The use of PePSi for frequency conversion can also be extended to terahertz generation. With integrated piezoelectric material, dynamically control of χ(2)nonlinearity in PePSi waveguide may also be achieved. The successful realization of PePSi based devices depends on the strength of the stress induced χ(2) in silicon. Presently, there exists a significant discrepancy in the literature between the theoretical and experimentally measured values. We present a simple theoretical model that produces result consistent with prior theoretical works and use this model to identify possible reasons for this discrepancy.

  20. Silicone metalization

    SciTech Connect

    Maghribi, Mariam N.; Krulevitch, Peter; Hamilton, Julie

    2008-12-09

    A system for providing metal features on silicone comprising providing a silicone layer on a matrix and providing a metal layer on the silicone layer. An electronic apparatus can be produced by the system. The electronic apparatus comprises a silicone body and metal features on the silicone body that provide an electronic device.

  1. Silicone metalization

    SciTech Connect

    Maghribi, Mariam N.; Krulevitch, Peter; Hamilton, Julie

    2006-12-05

    A system for providing metal features on silicone comprising providing a silicone layer on a matrix and providing a metal layer on the silicone layer. An electronic apparatus can be produced by the system. The electronic apparatus comprises a silicone body and metal features on the silicone body that provide an electronic device.

  2. Defensive strategies in Geranium sylvaticum, Part 2: Roles of water-soluble tannins, flavonoids and phenolic acids against natural enemies.

    PubMed

    Tuominen, Anu

    2013-11-01

    Geranium sylvaticum is a common herbaceous plant in Fennoscandia, which has a unique phenolic composition. Ellagitannins, proanthocyanidins, galloylglucoses, gallotannins, galloyl quinic acids and flavonoids possess variable distribution in its different organs. These phenolic compounds are thought to have an important role in plant-herbivore interactions. The aim of this study was to quantify these different water-soluble phenolic compounds and measure the biological activity of the eight organs of G. sylvaticum. Compounds were characterized and quantified using HPLC-DAD/MS, in addition, total proanthocyanidins were determined by BuOH-HCl assay and total phenolics by the Folin-Ciocalteau method. Two in vitro biological activity measurements were used: the prooxidant activity was measured by the browning assay and antioxidant activity by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Organ extracts were fractionated using column chromatography on Sephadex LH-20 and the activities of fractions was similarly measured to evaluate which polyphenol groups contributed the most to the biological activity of each organ. The data on the activity of fractions were examined by multivariate data analysis. The water-soluble extracts of leaves and pistils, which contained over 30% of the dry weight as ellagitannins, showed the highest pro-oxidant activity among the organ extracts. Fraction analysis revealed that flavonoids and galloyl quinic acids also exhibited high pro-oxidant activity. In contrast, the most antioxidant active organ extracts were those of the main roots and hairy roots that contained high amounts of proanthocyanidins in addition to ellagitannins. Analysis of the fractions showed that especially ellagitannins and galloyl quinic acids have high antioxidant activity. We conclude that G. sylvaticum allocates a significant amount of tannins in those plant parts that are important to the fitness of the plant and susceptible to natural enemies, i

  3. Simultaneous functions of the installed DAS/DAK formaldehyde-assimilation pathway and the original formaldehyde metabolic pathways enhance the ability of transgenic geranium to purify gaseous formaldehyde polluted environment.

    PubMed

    Zhou, Shengen; Xiao, Sunqin; Xuan, Xiuxia; Sun, Zhen; Li, Kunzhi; Chen, Limei

    2015-04-01

    The overexpression of dihydroxyacetone synthase (DAS) and dihydroxyacetone kinase (DAK) from methylotrophic yeasts in chloroplasts created a photosynthetic formaldehyde (HCHO)-assimilation pathway (DAS/DAK pathway) in transgenic tobacco. Geranium has abilities to absorb and metabolize HCHO. Results of this study showed that the installed DAS/DAK pathway functioning in chloroplasts greatly enhanced the role of the Calvin cycle in transgenic geranium under high concentrations of gaseous HCHO stress. Consequently, the yield of sugars from HCHO-assimilation increased approximately 6-fold in transgenic geranium leaves, and concomitantly, the role of three original HCHO metabolic pathways reduced, leading to a significant decrease in formic acid, citrate and glycine production from HCHO metabolism. Although the role of three metabolic pathways reduced in transgenic plants under high concentrations of gaseous HCHO stress, the installed DAS/DAK pathway could still function together with the original HCHO metabolic pathways. Consequently, the gaseous HCHO-resistance of transgenic plants was significantly improved, and the generation of H2O2 in the transgenic geranium leaves was significantly less than that in the wild type (WT) leaves. Under environmental-polluted gaseous HCHO stress for a long duration, the stomata conductance of transgenic plants remained approximately 2-fold higher than that of the WT, thereby increasing its ability to purify gaseous HCHO polluted environment.

  4. The vapor activity of oregano, perilla, tea tree, lavender, clove, and geranium oils against a Trichophyton mentagrophytes in a closed box.

    PubMed

    Inouye, Shigeharu; Nishiyama, Yayoi; Uchida, Katsuhisa; Hasumi, Yayoi; Yamaguchi, Hideyo; Abe, Shigeru

    2006-12-01

    The vapor activity of six essential oils against a Trichophyton mentagrophytes was examined using a closed box. The antifungal activity was determined from colony size, which was correlated with the inoculum size. As judged from the minimum inhibitory dose and the minimum fungicidal dose determined after vapor exposure for 24 h, the vapor activity of the six essential oils was ranked in the following order: oregano > clove, perilla > geranium, lavender, tea tree. The vapors of oregano, perilla, tea tree, and lavender oils killed the mycelia by short exposure, for 3 h, but the vapors of clove and geranium oils were only active after overnight exposure. The vapor of oregano and other oils induced lysis of the mycelia. Morphological examination by scanning electron microscope (SEM) revealed that the cell membrane and cell wall were damaged in a dose- and time-dependent manner by the action of oregano vapor, causing rupture and peeling of the cell wall, with small bulges coming from the cell membrane. The vapor activity increased after 24 h, but mycelial accumulation of the active oil constituents was maximized around 15 h, and then decreased in parallel with the decrease of vapor concentration. This suggested that the active constituent accumulated on the fungal cells around 15 h caused irreversible damage, which eventually led to cellular death.

  5. Spiral silicon drift detectors

    SciTech Connect

    Rehak, P.; Gatti, E.; Longoni, A.; Sampietro, M.; Holl, P.; Lutz, G.; Kemmer, J.; Prechtel, U.; Ziemann, T.

    1988-01-01

    An advanced large area silicon photodiode (and x-ray detector), called Spiral Drift Detector, was designed, produced and tested. The Spiral Detector belongs to the family of silicon drift detectors and is an improvement of the well known Cylindrical Drift Detector. In both detectors, signal electrons created in silicon by fast charged particles or photons are drifting toward a practically point-like collection anode. The capacitance of the anode is therefore kept at the minimum (0.1pF). The concentric rings of the cylindrical detector are replaced by a continuous spiral in the new detector. The spiral geometry detector design leads to a decrease of the detector leakage current. In the spiral detector all electrons generated at the silicon-silicon oxide interface are collected on a guard sink rather than contributing to the detector leakage current. The decrease of the leakage current reduces the parallel noise of the detector. This decrease of the leakage current and the very small capacities of the detector anode with a capacitively matched preamplifier may improve the energy resolution of Spiral Drift Detectors operating at room temperature down to about 50 electrons rms. This resolution is in the range attainable at present only by cooled semiconductor detectors. 5 refs., 10 figs.

  6. Hydrodynamic slip in silicon nanochannels

    NASA Astrophysics Data System (ADS)

    Ramos-Alvarado, Bladimir; Kumar, Satish; Peterson, G. P.

    2016-03-01

    Equilibrium and nonequilibrium molecular dynamics simulations were performed to better understand the hydrodynamic behavior of water flowing through silicon nanochannels. The water-silicon interaction potential was calibrated by means of size-independent molecular dynamics simulations of silicon wettability. The wettability of silicon was found to be dependent on the strength of the water-silicon interaction and the structure of the underlying surface. As a result, the anisotropy was found to be an important factor in the wettability of these types of crystalline solids. Using this premise as a fundamental starting point, the hydrodynamic slip in nanoconfined water was characterized using both equilibrium and nonequilibrium calculations of the slip length under low shear rate operating conditions. As was the case for the wettability analysis, the hydrodynamic slip was found to be dependent on the wetted solid surface atomic structure. Additionally, the interfacial water liquid structure was the most significant parameter to describe the hydrodynamic boundary condition. The calibration of the water-silicon interaction potential performed by matching the experimental contact angle of silicon led to the verification of the no-slip condition, experimentally reported for silicon nanochannels at low shear rates.

  7. Stinging Insect Matching Game

    MedlinePlus

    ... for Kids ▸ Stinging Insect Matching Game Share | Stinging Insect Matching Game Stinging insects can ruin summer fun for those who are ... the difference between the different kinds of stinging insects in order to keep your summer safe and ...

  8. Matching a Distribution by Matching Quantiles Estimation

    PubMed Central

    Sgouropoulos, Nikolaos; Yao, Qiwei; Yastremiz, Claudia

    2015-01-01

    Motivated by the problem of selecting representative portfolios for backtesting counterparty credit risks, we propose a matching quantiles estimation (MQE) method for matching a target distribution by that of a linear combination of a set of random variables. An iterative procedure based on the ordinary least-squares estimation (OLS) is proposed to compute MQE. MQE can be easily modified by adding a LASSO penalty term if a sparse representation is desired, or by restricting the matching within certain range of quantiles to match a part of the target distribution. The convergence of the algorithm and the asymptotic properties of the estimation, both with or without LASSO, are established. A measure and an associated statistical test are proposed to assess the goodness-of-match. The finite sample properties are illustrated by simulation. An application in selecting a counterparty representative portfolio with a real dataset is reported. The proposed MQE also finds applications in portfolio tracking, which demonstrates the usefulness of combining MQE with LASSO. PMID:26692592

  9. Matching a Distribution by Matching Quantiles Estimation.

    PubMed

    Sgouropoulos, Nikolaos; Yao, Qiwei; Yastremiz, Claudia

    2015-04-03

    Motivated by the problem of selecting representative portfolios for backtesting counterparty credit risks, we propose a matching quantiles estimation (MQE) method for matching a target distribution by that of a linear combination of a set of random variables. An iterative procedure based on the ordinary least-squares estimation (OLS) is proposed to compute MQE. MQE can be easily modified by adding a LASSO penalty term if a sparse representation is desired, or by restricting the matching within certain range of quantiles to match a part of the target distribution. The convergence of the algorithm and the asymptotic properties of the estimation, both with or without LASSO, are established. A measure and an associated statistical test are proposed to assess the goodness-of-match. The finite sample properties are illustrated by simulation. An application in selecting a counterparty representative portfolio with a real dataset is reported. The proposed MQE also finds applications in portfolio tracking, which demonstrates the usefulness of combining MQE with LASSO.

  10. Lipid membranes on nanostructured silicon.

    SciTech Connect

    Slade, Andrea Lynn; Lopez, Gabriel P.; Ista, Linnea K.; O'Brien, Michael J.; Sasaki, Darryl Yoshio; Bisong, Paul; Zeineldin, Reema R.; Last, Julie A.; Brueck, Stephen R. J.

    2004-12-01

    A unique composite nanoscale architecture that combines the self-organization and molecular dynamics of lipid membranes with a corrugated nanotextured silicon wafer was prepared and characterized with fluorescence microscopy and scanning probe microscopy. The goal of this project was to understand how such structures can be assembled for supported membrane research and how the interfacial interactions between the solid substrate and the soft, self-assembled material create unique physical and mechanical behavior through the confinement of phases in the membrane. The nanometer scale structure of the silicon wafer was produced through interference lithography followed by anisotropic wet etching. For the present study, a line pattern with 100 nm line widths, 200 nm depth and a pitch of 360 nm pitch was fabricated. Lipid membranes were successfully adsorbed on the structured silicon surface via membrane fusion techniques. The surface topology of the bilayer-Si structure was imaged using in situ tapping mode atomic force microscopy (AFM). The membrane was observed to drape over the silicon structure producing an undulated topology with amplitude of 40 nm that matched the 360 nm pitch of the silicon structure. Fluorescence recovery after photobleaching (FRAP) experiments found that on the microscale those same structures exhibit anisotropic lipid mobility that was coincident with the silicon substructure. The results showed that while the lipid membrane maintains much of its self-assembled structure in the composite architecture, the silicon substructure indeed influences the dynamics of the molecular motion within the membrane.

  11. Silicon spintronics.

    PubMed

    Jansen, Ron

    2012-04-23

    Worldwide efforts are underway to integrate semiconductors and magnetic materials, aiming to create a revolutionary and energy-efficient information technology in which digital data are encoded in the spin of electrons. Implementing spin functionality in silicon, the mainstream semiconductor, is vital to establish a spin-based electronics with potential to change information technology beyond imagination. Can silicon spintronics live up to the expectation? Remarkable advances in the creation and control of spin polarization in silicon suggest so. Here, I review the key developments and achievements, and describe the building blocks of silicon spintronics. Unexpected and puzzling results are discussed, and open issues and challenges identified. More surprises lie ahead as silicon spintronics comes of age.

  12. Ontology Matching Across Domains

    DTIC Science & Technology

    2010-05-01

    matching include GMO [1], Anchor-Prompt [2], and Similarity Flooding [3]. GMO is an iterative structural matcher, which uses RDF bipartite graphs to...AFRL under contract# FA8750-09-C-0058. References [1] Hu, W., Jian, N., Qu, Y., Wang, Y., “ GMO : a graph matching for ontologies”, in: Proceedings of

  13. DOE Matching Grant Program

    SciTech Connect

    Dr Marvin Adams

    2002-03-01

    OAK 270 - The DOE Matching Grant Program provided $50,000.00 to the Dept of N.E. at TAMU, matching a gift of $50,000.00 from TXU Electric. The $100,000.00 total was spent on scholarships, departmental labs, and computing network.

  14. Silicon nitride/silicon carbide composite powders

    DOEpatents

    Dunmead, Stephen D.; Weimer, Alan W.; Carroll, Daniel F.; Eisman, Glenn A.; Cochran, Gene A.; Susnitzky, David W.; Beaman, Donald R.; Nilsen, Kevin J.

    1996-06-11

    Prepare silicon nitride-silicon carbide composite powders by carbothermal reduction of crystalline silica powder, carbon powder and, optionally, crystalline silicon nitride powder. The crystalline silicon carbide portion of the composite powders has a mean number diameter less than about 700 nanometers and contains nitrogen. The composite powders may be used to prepare sintered ceramic bodies and self-reinforced silicon nitride ceramic bodies.

  15. Matched-pair classification

    SciTech Connect

    Theiler, James P

    2009-01-01

    Following an analogous distinction in statistical hypothesis testing, we investigate variants of machine learning where the training set comes in matched pairs. We demonstrate that even conventional classifiers can exhibit improved performance when the input data has a matched-pair structure. Online algorithms, in particular, converge quicker when the data is presented in pairs. In some scenarios (such as the weak signal detection problem), matched pairs can be generated from independent samples, with the effect not only doubling the nominal size of the training set, but of providing the structure that leads to better learning. A family of 'dipole' algorithms is introduced that explicitly takes advantage of matched-pair structure in the input data and leads to further performance gains. Finally, we illustrate the application of matched-pair learning to chemical plume detection in hyperspectral imagery.

  16. Learning graph matching.

    PubMed

    Caetano, Tibério S; McAuley, Julian J; Cheng, Li; Le, Quoc V; Smola, Alex J

    2009-06-01

    As a fundamental problem in pattern recognition, graph matching has applications in a variety of fields, from computer vision to computational biology. In graph matching, patterns are modeled as graphs and pattern recognition amounts to finding a correspondence between the nodes of different graphs. Many formulations of this problem can be cast in general as a quadratic assignment problem, where a linear term in the objective function encodes node compatibility and a quadratic term encodes edge compatibility. The main research focus in this theme is about designing efficient algorithms for approximately solving the quadratic assignment problem, since it is NP-hard. In this paper we turn our attention to a different question: how to estimate compatibility functions such that the solution of the resulting graph matching problem best matches the expected solution that a human would manually provide. We present a method for learning graph matching: the training examples are pairs of graphs and the 'labels' are matches between them. Our experimental results reveal that learning can substantially improve the performance of standard graph matching algorithms. In particular, we find that simple linear assignment with such a learning scheme outperforms Graduated Assignment with bistochastic normalisation, a state-of-the-art quadratic assignment relaxation algorithm.

  17. Latent fingerprint matching.

    PubMed

    Jain, Anil K; Feng, Jianjiang

    2011-01-01

    Latent fingerprint identification is of critical importance to law enforcement agencies in identifying suspects: Latent fingerprints are inadvertent impressions left by fingers on surfaces of objects. While tremendous progress has been made in plain and rolled fingerprint matching, latent fingerprint matching continues to be a difficult problem. Poor quality of ridge impressions, small finger area, and large nonlinear distortion are the main difficulties in latent fingerprint matching compared to plain or rolled fingerprint matching. We propose a system for matching latent fingerprints found at crime scenes to rolled fingerprints enrolled in law enforcement databases. In addition to minutiae, we also use extended features, including singularity, ridge quality map, ridge flow map, ridge wavelength map, and skeleton. We tested our system by matching 258 latents in the NIST SD27 database against a background database of 29,257 rolled fingerprints obtained by combining the NIST SD4, SD14, and SD27 databases. The minutiae-based baseline rank-1 identification rate of 34.9 percent was improved to 74 percent when extended features were used. In order to evaluate the relative importance of each extended feature, these features were incrementally used in the order of their cost in marking by latent experts. The experimental results indicate that singularity, ridge quality map, and ridge flow map are the most effective features in improving the matching accuracy.

  18. Cognitive Levels Matching.

    ERIC Educational Resources Information Center

    Brooks, Martin; And Others

    1983-01-01

    The Cognitive Levels Matching Project trains teachers to guide students' skill acquisition and problem-solving processes by assessing students' cognitive levels and adapting their teaching materials accordingly. (MLF)

  19. Project Matching Initiative

    EPA Pesticide Factsheets

    The Green Power Partnership's Project Matching initiative works to connect green power users with new, not-yet-built renewable energy projects that may align with their energy, environmental, and financial objectives.

  20. The molecular matching problem

    NASA Technical Reports Server (NTRS)

    Kincaid, Rex K.

    1993-01-01

    Molecular chemistry contains many difficult optimization problems that have begun to attract the attention of optimizers in the Operations Research community. Problems including protein folding, molecular conformation, molecular similarity, and molecular matching have been addressed. Minimum energy conformations for simple molecular structures such as water clusters, Lennard-Jones microclusters, and short polypeptides have dominated the literature to date. However, a variety of interesting problems exist and we focus here on a molecular structure matching (MSM) problem.

  1. Evaluation of the antifungal activity of Zataria multiflora, Geranium herbarium, and Eucalyptus camaldolensis essential oils on Saprolegnia parasitica-infected rainbow trout (Oncorhynchus mykiss) eggs.

    PubMed

    Khosravi, Ali Reza; Shokri, Hojjatollah; Sharifrohani, Mostafa; Mousavi, Hosseinali Ebrahimzadeh; Moosavi, Zahra

    2012-07-01

    The purpose of the present study was to evaluate and assess the capability of Zataria multiflora, Geranium herbarium, and Eucalyptus camaldolensis essential oils in treating Saprolegnia parasitica-infected rainbow (Oncorhynchus mykiss) trout eggs. A total of 150 infected eggs were collected and plated on glucose-pepton agar at 24°C for 2 weeks. The antifungal assay of essential oils against S. parasitica was determined by a macrodilution broth technique. The eggs were treated with essential oils at concentrations of 1, 5, 10, 25, 50, and 100 ppm daily with three repetitions until the eyed eggs stage. Of 150 eggs examined, S. parasitica (54.3%), Saprolegnia spp. (45%), and Fusarium solani (0.7%) were isolated. The minimum inhibitory concentrations of Z. multiflora, E. camaldolensis, and G. herbarium essential oils against S. parasitica were 0.9, 2.3, and 4.8 ppm, respectively. Zataria multiflora and E. camaldolensis at concentrations of 25, 50, and 100 ppm, and G. herbarium at concentration of 100 ppm had significant differences in comparison with negative control (p<0.05). The results revealed that malachite green, followed by Z. multiflora, E. camaldolensis, and G. herbarium treated eggs had remained the most number of final eyed eggs after treatment. The highest final larvae rates belonged to malachite green, E. camaldolensis, Z. multiflora, and G. herbarium, respectively. The most hatching rates were recorded with malachite green (22%), and then Z. multiflora (11%), E. camaldolensis (7%), G. herbarium (3%), and negative control (1%). Zataria multiflora and E. camaldolensis were more effective than G. herbarium for the treatment of S. parasitica-infected rainbow trout eggs in aquaculture environment.

  2. Gettering of interstitial iron in silicon by plasma-enhanced chemical vapour deposited silicon nitride films

    NASA Astrophysics Data System (ADS)

    Liu, A. Y.; Sun, C.; Markevich, V. P.; Peaker, A. R.; Murphy, J. D.; Macdonald, D.

    2016-11-01

    It is known that the interstitial iron concentration in silicon is reduced after annealing silicon wafers coated with plasma-enhanced chemical vapour deposited (PECVD) silicon nitride films. The underlying mechanism for the significant iron reduction has remained unclear and is investigated in this work. Secondary ion mass spectrometry (SIMS) depth profiling of iron is performed on annealed iron-contaminated single-crystalline silicon wafers passivated with PECVD silicon nitride films. SIMS measurements reveal a high concentration of iron uniformly distributed in the annealed silicon nitride films. This accumulation of iron in the silicon nitride film matches the interstitial iron loss in the silicon bulk. This finding conclusively shows that the interstitial iron is gettered by the silicon nitride films during annealing over a wide temperature range from 250 °C to 900 °C, via a segregation gettering effect. Further experimental evidence is presented to support this finding. Deep-level transient spectroscopy analysis shows that no new electrically active defects are formed in the silicon bulk after annealing iron-containing silicon with silicon nitride films, confirming that the interstitial iron loss is not due to a change in the chemical structure of iron related defects in the silicon bulk. In addition, once the annealed silicon nitride films are removed, subsequent high temperature processes do not result in any reappearance of iron. Finally, the experimentally measured iron decay kinetics are shown to agree with a model of iron diffusion to the surface gettering sites, indicating a diffusion-limited iron gettering process for temperatures below 700 °C. The gettering process is found to become reaction-limited at higher temperatures.

  3. Silicon microdosimetry.

    PubMed

    Agosteo, Stefano; Pola, Andrea

    2011-02-01

    Silicon detectors are being studied as microdosemeters since they can provide sensitive volumes of micrometric dimensions. They can be applied for assessing single-event effects in electronic instrumentation exposed to complex fields around high-energy accelerators or in space missions. When coupled to tissue-equivalent converters, they can be used for measuring the quality of radiation therapy beams or for dosimetry. The use of micrometric volumes avoids the contribution of wall effects to the measured spectra. Further advantages of such detectors are their compactness, cheapness, transportability and a low sensitivity to vibrations. The following problems need to be solved when silicon devices are used for microdosimetry: (i) the sensitive volume has to be confined in a region of well-known dimensions; (ii) the electric noise limits the minimum detectable energy; (iii) corrections for tissue-equivalency should be made; (iv) corrections for shape equivalency should be made when referring to a spherical simulated site of tissue; (v) the angular response should be evaluated carefully; (vi) the efficiency of a single detector of micrometric dimensions is very poor and detector arrays should be considered. Several devices have been proposed as silicon microdosemeters, based on different technologies (telescope detectors, silicon on insulator detectors and arrays of cylindrical p-n junctions with internal amplification), in order to satisfy the issues mentioned above.

  4. Silicon-micromachined microchannel plates

    NASA Astrophysics Data System (ADS)

    Beetz, Charles P.; Boerstler, Robert; Steinbeck, John; Lemieux, Bryan; Winn, David R.

    2000-03-01

    Microchannel plates (MCP) fabricated from standard silicon wafer substrates using a novel silicon micromachining process, together with standard silicon photolithographic process steps, are described. The resulting SiMCP microchannels have dimensions of ˜0.5 to ˜25 μm, with aspect ratios up to 300, and have the dimensional precision and absence of interstitial defects characteristic of photolithographic processing, compatible with positional matching to silicon electronics readouts. The open channel areal fraction and detection efficiency may exceed 90% on plates up to 300 mm in diameter. The resulting silicon substrates can be converted entirely to amorphous quartz (qMCP). The strip resistance and secondary emission are developed by controlled depositions of thin films, at temperatures up to 1200°C, also compatible with high-temperture brazing, and can be essentially hydrogen, water and radionuclide-free. Novel secondary emitters and cesiated photocathodes can be high-temperature deposited or nucleated in the channels or the first strike surface. Results on resistivity, secondary emission and gain are presented.

  5. Asynchronous event-based binocular stereo matching.

    PubMed

    Rogister, Paul; Benosman, Ryad; Ieng, Sio-Hoi; Lichtsteiner, Patrick; Delbruck, Tobi

    2012-02-01

    We present a novel event-based stereo matching algorithm that exploits the asynchronous visual events from a pair of silicon retinas. Unlike conventional frame-based cameras, recent artificial retinas transmit their outputs as a continuous stream of asynchronous temporal events, in a manner similar to the output cells of the biological retina. Our algorithm uses the timing information carried by this representation in addressing the stereo-matching problem on moving objects. Using the high temporal resolution of the acquired data stream for the dynamic vision sensor, we show that matching on the timing of the visual events provides a new solution to the real-time computation of 3-D objects when combined with geometric constraints using the distance to the epipolar lines. The proposed algorithm is able to filter out incorrect matches and to accurately reconstruct the depth of moving objects despite the low spatial resolution of the sensor. This brief sets up the principles for further event-based vision processing and demonstrates the importance of dynamic information and spike timing in processing asynchronous streams of visual events.

  6. Is matching innate?

    PubMed

    Gallistel, C R; King, Adam Philip; Gottlieb, Daniel; Balci, Fuat; Papachristos, Efstathios B; Szalecki, Matthew; Carbone, Kimberly S

    2007-03-01

    Experimentally naive mice matched the proportions of their temporal investments (visit durations) in two feeding hoppers to the proportions of the food income (pellets per unit session time) derived from them in three experiments that varied the coupling between the behavioral investment and food income, from no coupling to strict coupling. Matching was observed from the outset; it did not improve with training. When the numbers of pellets received were proportional to time invested, investment was unstable, swinging abruptly from sustained, almost complete investment in one hopper, to sustained, almost complete investment in the other-in the absence of appropriate local fluctuations in returns (pellets obtained per time invested). The abruptness of the swings strongly constrains possible models. We suggest that matching reflects an innate (unconditioned) program that matches the ratio of expected visit durations to the ratio between the current estimates of expected incomes. A model that processes the income stream looking for changes in the income and generates discontinuous income estimates when a change is detected is shown to account for salient features of the data.

  7. Factorized Graph Matching.

    PubMed

    Zhou, Feng; de la Torre, Fernando

    2015-11-19

    Graph matching (GM) is a fundamental problem in computer science, and it plays a central role to solve correspondence problems in computer vision. GM problems that incorporate pairwise constraints can be formulated as a quadratic assignment problem (QAP). Although widely used, solving the correspondence problem through GM has two main limitations: (1) the QAP is NP-hard and difficult to approximate; (2) GM algorithms do not incorporate geometric constraints between nodes that are natural in computer vision problems. To address aforementioned problems, this paper proposes factorized graph matching (FGM). FGM factorizes the large pairwise affinity matrix into smaller matrices that encode the local structure of each graph and the pairwise affinity between edges. Four are the benefits that follow from this factorization: (1) There is no need to compute the costly (in space and time) pairwise affinity matrix; (2) The factorization allows the use of a path-following optimization algorithm, that leads to improved optimization strategies and matching performance; (3) Given the factorization, it becomes straight-forward to incorporate geometric transformations (rigid and non-rigid) to the GM problem. (4) Using a matrix formulation for the GM problem and the factorization, it is easy to reveal commonalities and differences between different GM methods. The factorization also provides a clean connection with other matching algorithms such as iterative closest point; Experimental results on synthetic and real databases illustrate how FGM outperforms state-of-the-art algorithms for GM. The code is available at http://humansensing.cs.cmu.edu/fgm.

  8. Inter-image matching

    NASA Technical Reports Server (NTRS)

    Wolfe, R. H., Jr.; Juday, R. D.

    1982-01-01

    Interimage matching is the process of determining the geometric transformation required to conform spatially one image to another. In principle, the parameters of that transformation are varied until some measure of some difference between the two images is minimized or some measure of sameness (e.g., cross-correlation) is maximized. The number of such parameters to vary is faily large (six for merely an affine transformation), and it is customary to attempt an a priori transformation reducing the complexity of the residual transformation or subdivide the image into small enough match zones (control points or patches) that a simple transformation (e.g., pure translation) is applicable, yet large enough to facilitate matching. In the latter case, a complex mapping function is fit to the results (e.g., translation offsets) in all the patches. The methods reviewed have all chosen one or both of the above options, ranging from a priori along-line correction for line-dependent effects (the high-frequency correction) to a full sensor-to-geobase transformation with subsequent subdivision into a grid of match points.

  9. Is Matching Innate?

    ERIC Educational Resources Information Center

    Gallistel, C. R.; King, Adam Philip; Gottlieb, Daniel; Balci, Fuat; Papachristos, Efstathios B.; Szalecki, Matthew; Carbone, Kimberly S.

    2007-01-01

    Experimentally naive mice matched the proportions of their temporal investments (visit durations) in two feeding hoppers to the proportions of the food income (pellets per unit session time) derived from them in three experiments that varied the coupling between the behavioral investment and food income, from no coupling to strict coupling.…

  10. Derivatives of Matching.

    ERIC Educational Resources Information Center

    Herrnstein, R. J.

    1979-01-01

    The matching law for reinforced behavior solves a differential equation relating infinitesimal changes in behavior to infinitesimal changes in reinforcement. The equation expresses plausible conceptions of behavior and reinforcement, yields a simple nonlinear operator model for acquisition, and suggests a alternative to the economic law of…

  11. Matching Supernovae to Galaxies

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-12-01

    developed a new automated algorithm for matching supernovae to their host galaxies. Their work builds on currently existing algorithms and makes use of information about the nearby galaxies, accounts for the uncertainty of the match, and even includes a machine learning component to improve the matching accuracy.Gupta and collaborators test their matching algorithm on catalogs of galaxies and simulated supernova events to quantify how well the algorithm is able to accurately recover the true hosts.Successful MatchingThe matching algorithms accuracy (purity) as a function of the true supernova-host separation, the supernova redshift, the true hosts brightness, and the true hosts size. [Gupta et al. 2016]The authors find that when the basic algorithm is run on catalog data, it matches supernovae to their hosts with 91% accuracy. Including the machine learning component, which is run after the initial matching algorithm, improves the accuracy of the matching to 97%.The encouraging results of this work which was intended as a proof of concept suggest that methods similar to this could prove very practical for tackling future survey data. And the method explored here has use beyond matching just supernovae to their host galaxies: it could also be applied to other extragalactic transients, such as gamma-ray bursts, tidal disruption events, or electromagnetic counterparts to gravitational-wave detections.CitationRavi R. Gupta et al 2016 AJ 152 154. doi:10.3847/0004-6256/152/6/154

  12. Quantitative analysis of the thermal requirements for stepwise physical dormancy-break in seeds of the winter annual Geranium carolinianum (Geraniaceae)

    PubMed Central

    Gama-Arachchige, N. S.; Baskin, J. M.; Geneve, R. L.; Baskin, C. C.

    2013-01-01

    Background and Aims Physical dormancy (PY)-break in some annual plant species is a two-step process controlled by two different temperature and/or moisture regimes. The thermal time model has been used to quantify PY-break in several species of Fabaceae, but not to describe stepwise PY-break. The primary aims of this study were to quantify the thermal requirement for sensitivity induction by developing a thermal time model and to propose a mechanism for stepwise PY-breaking in the winter annual Geranium carolinianum. Methods Seeds of G. carolinianum were stored under dry conditions at different constant and alternating temperatures to induce sensitivity (step I). Sensitivity induction was analysed based on the thermal time approach using the Gompertz function. The effect of temperature on step II was studied by incubating sensitive seeds at low temperatures. Scanning electron microscopy, penetrometer techniques, and different humidity levels and temperatures were used to explain the mechanism of stepwise PY-break. Key Results The base temperature (Tb) for sensitivity induction was 17·2 °C and constant for all seed fractions of the population. Thermal time for sensitivity induction during step I in the PY-breaking process agreed with the three-parameter Gompertz model. Step II (PY-break) did not agree with the thermal time concept. Q10 values for the rate of sensitivity induction and PY-break were between 2·0 and 3·5 and between 0·02 and 0·1, respectively. The force required to separate the water gap palisade layer from the sub-palisade layer was significantly reduced after sensitivity induction. Conclusions Step I and step II in PY-breaking of G. carolinianum are controlled by chemical and physical processes, respectively. This study indicates the feasibility of applying the developed thermal time model to predict or manipulate sensitivity induction in seeds with two-step PY-breaking processes. The model is the first and most detailed one yet developed for

  13. Resurgence matches quantization

    NASA Astrophysics Data System (ADS)

    Couso-Santamaría, Ricardo; Mariño, Marcos; Schiappa, Ricardo

    2017-04-01

    The quest to find a nonperturbative formulation of topological string theory has recently seen two unrelated developments. On the one hand, via quantization of the mirror curve associated to a toric Calabi–Yau background, it has been possible to give a nonperturbative definition of the topological-string partition function. On the other hand, using techniques of resurgence and transseries, it has been possible to extend the string (asymptotic) perturbative expansion into a transseries involving nonperturbative instanton sectors. Within the specific example of the local {{{P}}2} toric Calabi–Yau threefold, the present work shows how the Borel–Padé–Écalle resummation of this resurgent transseries, alongside occurrence of Stokes phenomenon, matches the string-theoretic partition function obtained via quantization of the mirror curve. This match is highly non-trivial, given the unrelated nature of both nonperturbative frameworks, signaling at the existence of a consistent underlying structure.

  14. Surface matching via currents.

    PubMed

    Vaillant, Marc; Glaunès, Joan

    2005-01-01

    We present a new method for computing an optimal deformation between two arbitrary surfaces embedded in Euclidean 3-dimensional space. Our main contribution is in building a norm on the space of surfaces via representation by currents of geometric measure theory. Currents are an appropriate choice for representations because they inherit natural transformation properties from differential forms. We impose a Hilbert space structure on currents, whose norm gives a convenient and practical way to define a matching functional. Using this Hilbert space norm, we also derive and implement a surface matching algorithm under the large deformation framework, guaranteeing that the optimal solution is a one-to-one regular map of the entire ambient space. We detail an implementation of this algorithm for triangular meshes and present results on 3D face and medical image data.

  15. Interspecific variation in SO/sub 2/ flux: leaf surface versus internal flux, and components of leaf conductance. [Pisum sativum L. , Lycopersicon esculentum Mill. Flacca, Geranium carolinianum L. , Diplacus aurantiacus (Curtis) Jeps

    SciTech Connect

    Olszyk, D.M.; Tingey, D.T.

    1985-12-01

    The objective of this study was to clarify the relationships among stomatal, residual, and epidermal conductances in determining the flux of SO/sub 2/ air pollution to leaves. Variations in leaf SO/sub 2/ and H/sub 2/O vapor fluxes were determined using four plant species: Pisum sativum L. (garden pea), Lycopersicon esculentum Mill. flacca (mutant of tomato), Geranium carolinianum L. (wild geranium), and Diplacus aurantiacus (Curtis) Jeps. (a native California shrub). Fluxes were measured using the mass-balance approach during exposure to 4.56 micromoles per cubic meter (0.11 microliters per liter) SO/sub 2/ for 2 hours in a controlled environmental chamber. Flux through adaxial and abaxial leaf surfaces with closed stomata ranged from 1.9 to 9.4 nanomoles per square meter per second for SO/sub 2/, and 0.3 to 1.3 millimoles per square meter per second for H/sub 2/O vapor. Flux of SO/sub 2/ into leaves through stomata ranged from approx.0 to 8.5 (dark) and 3.8 to 16.0 (light) millimoles per square meter per second. Flux of H/sub 2/O vapor from leaves through stomata ranged from approx.0 to 0.6 (dark) to 0.4 to 0.9 (light) millimole per square meter per second. Lycopersicon had internal flux rates for both SO/sub 2/ and H/sub 2/O vapor over twice as high as for the other species. Stomatal conductance based on H/sub 2/O vapor flux averaged from 0.07 to 0.13 mole per square meter per second among the four species. Internal conductance of SO/sub 2/ as calculated from SO/sub 2/ flux was from 0.04 mole per square meter per second lower to 0.06 mole per square meter per second higher than stomatal conductance. For Pisum, Geranium, and Diplacus stomatal conductance was the same or slightly higher than internal conductance, indicating that, in general, SO/sub 2/ flux could be predicted from stomatal conductance for H/sub 2/O vapor.

  16. Silicon Detectors

    NASA Astrophysics Data System (ADS)

    Sadrozinski, Hartmut

    2014-03-01

    The use of silicon detectors has experienced an exponential growth in accelerator and space based experiments, similar to trends in the semiconductor industry as a whole, usually paraphrased as ``Moore's Law.'' Some of the essentials for this phenomenon will be presented, together with examples of the exciting science results which it enabled. With the establishment of a ``semiconductor culture'' in universities and laboratories around the world, an increased understanding of the sensors results in thinner, faster, more radiation-resistant detectors, spawning an amazing wealth of new technologies and applications, which will be the main subject of the presentation.

  17. Fumigant antitermitic activity of plant essential oils and components from Ajowan ( Trachyspermum ammi ), Allspice ( Pimenta dioica ), caraway ( Carum carvi ), dill ( Anethum graveolens ), Geranium ( Pelargonium graveolens ), and Litsea ( Litsea cubeba ) oils against Japanese termite ( Reticulitermes speratus Kolbe).

    PubMed

    Seo, Seon-Mi; Kim, Junheon; Lee, Sang-Gil; Shin, Chang-Hoon; Shin, Sang-Chul; Park, Il-Kwon

    2009-08-12

    Plant essential oils from 26 plant species were tested for their insecticidal activities against the Japanese termite, Reticulitermes speratus Kolbe, using a fumigation bioassay. Responses varied with source, exposure time, and concentration. Among the essential oils tested, strong insecticidal activity was observed with the essential oils of ajowan ( Trachyspermum ammi ), allspice ( Pimenta dioica ), caraway ( Carum carvi ), dill ( Anethum graveolens ), geranium ( Pelargonium graveolens ), and litsea ( Litsea cubeba ). The composition of six essential oils was identified by using gas chromatography-mass spectrometry. The compounds thus identified were tested individually for their insecticidal activities against Japanese termites. Responses varied in a dose-dependent manner for each compound. Phenol compounds exhibited the strongest insecticidal activity among the test compounds; furthermore, alcohol and aldehyde groups were more toxic than hydrocarbons. The essential oils and compounds described herein merit further study as potential fumigants for termite control.

  18. Skyline based terrain matching

    NASA Technical Reports Server (NTRS)

    Page, Lance A.

    1990-01-01

    Skyline-based terrain matching, a new method for locating the vantage point of stereo camera or laser range-finding measurements on a global map previously prepared by satellite or aerial mapping is described. The orientation of the vantage is assumed known, but its translational parameters are determined by the algorithm. Skylines, or occluding contours, can be extracted from the sensory measurements taken by an autonomous vehicle. They can also be modeled from the global map, given a vantage estimate from which to start. The two sets of skylines, represented in cylindrical coordinates about either the true or the estimated vantage, are employed as 'features' or reference objects common to both sources of information. The terrain matching problem is formulated in terms of finding a translation between the respective representations of the skylines, by approximating the two sets of skylines as identical features (curves) on the actual terrain. The search for this translation is based on selecting the longest of the minimum-distance vectors between corresponding curves from the two sets of skylines. In successive iterations of the algorithm, the approximation that the two sets of curves are identical becomes more accurate, and the vantage estimate continues to improve. The algorithm was implemented and evaluated on a simulated terrain. Illustrations and examples are included.

  19. Digital matched filter ASIC

    NASA Astrophysics Data System (ADS)

    Magill, D. T.; Edwards, G.

    The architecture of a digital matched filter (DMF) and the selected technology used is described. The characteristics of the DMF ASIC are summarized in tabular form. Three architectures are considered for the implementation of a DMF ASIC. First, there is the conventional trapped delay line architecture which requires a large adder tree. The second architecture is the systolic array DMF which consists of a number of identical stages cascaded together. The third architecture is the bank-of-correlators DMF, in which the reference code is recirculated around through the delay line. Since the objective is to maximize the length of the DMF, the tapped delay line architecture is selected. The tapped delay form is designed to support BPSK, QPSK, and OQPSK chip modulation. Matched filter lengths of up to 256 chips can be supported by cascading 4 ASICs. The DMF is designed as a gate array using an advanced double metal, 1.5 micron CMOS process. The regularity of FIR filter architecture allows the core of the device to be laid out very compactly, resulting in efficient usage of the gate array.

  20. Expression of a delta 9 14:0-acyl carrier protein fatty acid desaturase gene is necessary for the production of omega 5 anacardic acids found in pest-resistant geranium (Pelargonium xhortorum).

    PubMed Central

    Schultz, D J; Cahoon, E B; Shanklin, J; Craig, R; Cox-Foster, D L; Mumma, R O; Medford, J I

    1996-01-01

    Anacardic acids, a class of secondary compounds derived from fatty acids, are found in a variety of dicotyledonous families. Pest resistance (e.g., spider mites and aphids) in Pelargonium xhortorum (geranium) is associated with high levels (approximately 81%) of unsaturated 22:1 omega 5 and 24:1 omega 5 anacardic acids in the glandular trichome exudate. A single dominant locus controls the production of these omega 5 anacardic acids, which arise from novel 16:1 delta 11 and 18:1 delta 13 fatty acids. We describe the isolation and characterization of a cDNA encoding a unique delta 9 14:0-acyl carrier protein fatty acid desaturase. Several lines of evidence indicated that expression of this desaturase leads to the production of the omega 5 anacardic acids involved in pest resistance. First, its expression was found in pest-resistant, but not suspectible, plants and its expression followed the production of the omega 5 anacardic acids in segregating populations. Second, its expression and the occurrence of the novel 16:1 delta 11 and 18:1 delta 13 fatty acids and the omega 5 anacardic acids were specific to tall glandular trichomes. Third, assays of the recombinant protein demonstrated that this desaturase produced the 14:1 delta 9 fatty acid precursor to the novel 16:1 delta 11 and 18:1 delta 13 fatty acids. Based on our genetic and biochemical studies, we conclude that expression of this delta 9 14:0-ACP desaturase gene is required for the production of omega 5 anacardic acids that have been shown to be necessary for pest resistance in geranium. Images Fig. 1 Fig. 3 Fig. 5 PMID:8710947

  1. The Earliest Matches

    PubMed Central

    Goren-Inbar, Naama; Freikman, Michael; Garfinkel, Yosef; Goring-Morris, Nigel A.; Grosman, Leore

    2012-01-01

    Cylindrical objects made usually of fired clay but sometimes of stone were found at the Yarmukian Pottery Neolithic sites of Sha‘ar HaGolan and Munhata (first half of the 8th millennium BP) in the Jordan Valley. Similar objects have been reported from other Near Eastern Pottery Neolithic sites. Most scholars have interpreted them as cultic objects in the shape of phalli, while others have referred to them in more general terms as “clay pestles,” “clay rods,” and “cylindrical clay objects.” Re-examination of these artifacts leads us to present a new interpretation of their function and to suggest a reconstruction of their technology and mode of use. We suggest that these objects were components of fire drills and consider them the earliest evidence of a complex technology of fire ignition, which incorporates the cylindrical objects in the role of matches. PMID:22870306

  2. The earliest matches.

    PubMed

    Goren-Inbar, Naama; Freikman, Michael; Garfinkel, Yosef; Goring-Morris, A Nigel; Goring-Morris, Nigel A; Grosman, Leore

    2012-01-01

    Cylindrical objects made usually of fired clay but sometimes of stone were found at the Yarmukian Pottery Neolithic sites of Sha'ar HaGolan and Munhata (first half of the 8(th) millennium BP) in the Jordan Valley. Similar objects have been reported from other Near Eastern Pottery Neolithic sites. Most scholars have interpreted them as cultic objects in the shape of phalli, while others have referred to them in more general terms as "clay pestles," "clay rods," and "cylindrical clay objects." Re-examination of these artifacts leads us to present a new interpretation of their function and to suggest a reconstruction of their technology and mode of use. We suggest that these objects were components of fire drills and consider them the earliest evidence of a complex technology of fire ignition, which incorporates the cylindrical objects in the role of matches.

  3. Silicon carbide

    SciTech Connect

    Ault, N.N.; Crowe, J.T. )

    1991-05-01

    This paper reports that, since silicon carbide (SiC) does not occur in nature, it must be synthesized by a high-temperature chemical reaction. The first commercial production began at the end of the 19th century when Acheson developed a process of reacting sand and coke in a resistance furnace. This process is still the basic SiC manufacturing process used today. High-quality silica sand (99.5% SiO{sub 2}), low-sulfur petroleum coke, and electricity (23.8 MJ/kg) are the major ingredients in the production of SiC. The reaction takes place in a trough-like furnace with a removable refractory side (or some similar configuration) and with permanent refractory ends holding carbon electrodes. When the furnace is started, the carbon electrodes are joined by the graphite core laid the length of the furnace near the center of the mixture which fills the furnace.

  4. Distinctiveness Maps for Image Matching

    NASA Technical Reports Server (NTRS)

    Manduchi, Roberto; Tomasi, Carlo

    2000-01-01

    Stereo correspondence is hard because different image features can look alike. We propose a measure for the ambiguity of image points that allows matching distinctive points first and breaks down the matching task into smaller and separate subproblems. Experiments with an algorithm based on this measure demonstrate the ensuing efficiency and low likelihood of incorrect matches.

  5. Thin silicon solar cells

    SciTech Connect

    Hall, R.B.; Bacon, C.; DiReda, V.; Ford, D.H.; Ingram, A.E.; Cotter, J.; Hughes-Lampros, T.; Rand, J.A.; Ruffins, T.R.; Barnett, A.M.

    1992-12-01

    The silicon-film design achieves high performance by using a dun silicon layer and incorporating light trapping. Optimally designed thin crystalline solar cells (<50 microns thick) have performance advantages over conventional thick devices. The high-performance silicon-film design employs a metallurgical barrier between the low-cost substrate and the thin silicon layer. Light trapping properties of silicon-film on ceramic solar cells are presented and analyzed. Recent advances in process development are described here.

  6. Proton straggling in thick silicon detectors

    NASA Astrophysics Data System (ADS)

    Selesnick, R. S.; Baker, D. N.; Kanekal, S. G.

    2017-03-01

    Straggling functions for protons in thick silicon radiation detectors are computed by Monte Carlo simulation. Mean energy loss is constrained by the silicon stopping power, providing higher straggling at low energy and probabilities for stopping within the detector volume. By matching the first four moments of simulated energy-loss distributions, straggling functions are approximated by a log-normal distribution that is accurate for Vavilov κ ≳ 0.3 . They are verified by comparison to experimental proton data from a charged particle telescope.

  7. Buried oxide layer in silicon

    DOEpatents

    Sadana, Devendra Kumar; Holland, Orin Wayne

    2001-01-01

    A process for forming Silicon-On-Insulator is described incorporating the steps of ion implantation of oxygen into a silicon substrate at elevated temperature, ion implanting oxygen at a temperature below 200.degree. C. at a lower dose to form an amorphous silicon layer, and annealing steps to form a mixture of defective single crystal silicon and polycrystalline silicon or polycrystalline silicon alone and then silicon oxide from the amorphous silicon layer to form a continuous silicon oxide layer below the surface of the silicon substrate to provide an isolated superficial layer of silicon. The invention overcomes the problem of buried isolated islands of silicon oxide forming a discontinuous buried oxide layer.

  8. Constraint-based stereo matching

    NASA Technical Reports Server (NTRS)

    Kuan, D. T.

    1987-01-01

    The major difficulty in stereo vision is the correspondence problem that requires matching features in two stereo images. Researchers describe a constraint-based stereo matching technique using local geometric constraints among edge segments to limit the search space and to resolve matching ambiguity. Edge segments are used as image features for stereo matching. Epipolar constraint and individual edge properties are used to determine possible initial matches between edge segments in a stereo image pair. Local edge geometric attributes such as continuity, junction structure, and edge neighborhood relations are used as constraints to guide the stereo matching process. The result is a locally consistent set of edge segment correspondences between stereo images. These locally consistent matches are used to generate higher-level hypotheses on extended edge segments and junctions to form more global contexts to achieve global consistency.

  9. Feature-accelerated block matching

    NASA Astrophysics Data System (ADS)

    Tao, Bo; Orchard, Michael T.

    1998-01-01

    We study the relationship between local features and block matching in this paper. We show that the use of many features can greatly improve the block matching results by introducing several fast block matching algorithms. The first algorithm is pixel decimation-based. We show that pixels with larger gradient magnitude have larger motion compensation error. Therefore for pixel decimation-based fast block matching, it benefits to subsample the block by selecting pixels with the largest gradient magnitude. Such a gradient-assisted adaptive pixel selection strategy greatly outperforms two other subsampling procedures proposed in previous literature. Fast block matching can achieve the optimal performance obtained using full search. We present a family of such fast block matching algorithm using various local features, such as block mean and variance. Our algorithm reduces more than 80 percent computation, while achieving the same performance as the full search. This present a brand new approach toward fast block matching algorithm design.

  10. Purified silicon production system

    DOEpatents

    Wang, Tihu; Ciszek, Theodore F.

    2004-03-30

    Method and apparatus for producing purified bulk silicon from highly impure metallurgical-grade silicon source material at atmospheric pressure. Method involves: (1) initially reacting iodine and metallurgical-grade silicon to create silicon tetraiodide and impurity iodide byproducts in a cold-wall reactor chamber; (2) isolating silicon tetraiodide from the impurity iodide byproducts and purifying it by distillation in a distillation chamber; and (3) transferring the purified silicon tetraiodide back to the cold-wall reactor chamber, reacting it with additional iodine and metallurgical-grade silicon to produce silicon diiodide and depositing the silicon diiodide onto a substrate within the cold-wall reactor chamber. The two chambers are at atmospheric pressure and the system is open to allow the introduction of additional source material and to remove and replace finished substrates.

  11. Breast Implants: Saline vs. Silicone

    MedlinePlus

    ... to women of any age for breast reconstruction. Silicone breast implants Silicone implants are pre-filled with ... likely be inserted at the same time. Ruptured silicone implant If a silicone breast implant ruptures, you ...

  12. DOE Matching Grant Program

    SciTech Connect

    Tsoukalas, L.

    2002-12-31

    Funding used to support a portion of the Nuclear Engineering Educational Activities. Upgrade of teaching labs, student support to attend professional conferences, salary support for graduate students. The US Department of Energy (DOE) has funded Purdue University School of Nuclear Engineering during the period of five academic years covered in this report starting in the academic year 1996-97 and ending in the academic year 2000-2001. The total amount of funding for the grant received from DOE is $416K. In the 1990's, Nuclear Engineering Education in the US experienced a significant slow down. Student enrollment, research support, number of degrees at all levels (BS, MS, and PhD), number of accredited programs, University Research and Training Reactors, all went through a decline to alarmingly low levels. Several departments closed down, while some were amalgamated with other academic units (Mechanical Engineering, Chemical Engineering, etc). The School of Nuclear Engineering at Purdue University faced a major challenge when in the mid 90's our total undergraduate enrollment for the Sophomore, Junior and Senior Years dropped in the low 30's. The DOE Matching Grant program greatly strengthened Purdue's commitment to the Nuclear Engineering discipline and has helped to dramatically improve our undergraduate and graduate enrollment, attract new faculty and raise the School of Nuclear Engineering status within the University and in the National scene (our undergraduate enrollment has actually tripled and stands at an all time high of over 90 students; total enrollment currently exceeds 110 students). In this final technical report we outline and summarize how the grant was expended at Purdue University.

  13. The mode matching technology for MEMS gyroscopes with mutually spaced eigenfrequencies

    NASA Astrophysics Data System (ADS)

    Morozov, O.; Postnikov, A.; Kozin, I.; Soloviev, A.; Tarasov, A.

    2013-01-01

    Paper presents a new technology for silicon micromachined gyroscope mode matching with mutually spaced eigenfrequencies. The fabrication of gyroscope sensing element is based on double-sided deep reactive ion etching (DRIE) of standard silicon wafer and allows full 3D control of the gimbals and flexures geometry. The developed finite element model allows predicting dynamic characteristics of sensing element versus geometry of flexible suspension beams. Oxidation and successive wet etching of SiO2 layer lead to flexure geometry change (thinning). One-to-one correspondence of measured resonant frequencies and flexures geometry defines the oxidation depth. The mode matching condition is achieved by repeated oxidation-wet etching cycles.

  14. Complexity matching in dyadic conversation.

    PubMed

    Abney, Drew H; Paxton, Alexandra; Dale, Rick; Kello, Christopher T

    2014-12-01

    Recent studies of dyadic interaction have examined phenomena of synchronization, entrainment, alignment, and convergence. All these forms of behavioral matching have been hypothesized to play a supportive role in establishing coordination and common ground between interlocutors. In the present study, evidence is found for a new kind of coordination termed complexity matching. Temporal dynamics in conversational speech signals were analyzed through time series of acoustic onset events. Timing in periods of acoustic energy was found to exhibit behavioral matching that reflects complementary timing in turn-taking. In addition, acoustic onset times were found to exhibit power law clustering across a range of timescales, and these power law functions were found to exhibit complexity matching that is distinct from behavioral matching. Complexity matching is discussed in terms of interactive alignment and other theoretical principles that lead to new hypotheses about information exchange in dyadic conversation and interaction in general.

  15. Substrate for thin silicon solar cells

    DOEpatents

    Ciszek, T.F.

    1995-03-28

    A photovoltaic device for converting solar energy into electrical signals comprises a substrate, a layer of photoconductive semiconductor material grown on said substrate, wherein the substrate comprises an alloy of boron and silicon, the boron being present in a range of from 0.1 to 1.3 atomic percent, the alloy having a lattice constant substantially matched to that of the photoconductive semiconductor material and a resistivity of less than 1{times}10{sup {minus}3} ohm-cm. 4 figures.

  16. Process for producing silicon

    DOEpatents

    Olson, Jerry M.; Carleton, Karen L.

    1984-01-01

    A process for producing silicon includes forming an alloy of copper and silicon and positioning the alloy in a dried, molten salt electrolyte to form a solid anode structure therein. An electrically conductive cathode is placed in the electrolyte for plating silicon thereon. The electrolyte is then purified to remove dissolved oxides. Finally, an electrical potential is applied between the anode and cathode in an amount sufficient to form substantially pure silicon on the cathode in the form of substantially dense, coherent deposits.

  17. Hugoniot Measurements of Silicon Shock Compressed to 25 Mbar

    NASA Astrophysics Data System (ADS)

    Henderson, B.; Polsin, D. N.; Boehly, T. R.; Gregor, M. C.; Hu, S. X.; Collins, G. W.; Rygg, J. R.; Fratanduono, D. E.; Celliers, P. M.

    2016-10-01

    We present results of laser-driven shock experiments that compressed silicon samples to 25 Mbar. Impedance matching to a quartz reference provided Hugoniot data. Since silicon is opaque, a quartz witness was placed adjacent to the silicon samples; this afforded the use of the unsteady wave correction to increase the precision of the transit-time measurements of shock velocity. Results are compared both SESAME tables and to quantum molecular dynamics calculations. This material is based upon work supported by the Department Of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  18. Electrodeposition of molten silicon

    DOEpatents

    De Mattei, Robert C.; Elwell, Dennis; Feigelson, Robert S.

    1981-01-01

    Silicon dioxide is dissolved in a molten electrolytic bath, preferably comprising barium oxide and barium fluoride. A direct current is passed between an anode and a cathode in the bath to reduce the dissolved silicon dioxide to non-alloyed silicon in molten form, which is removed from the bath.

  19. Efficient Silicon Reactor

    NASA Technical Reports Server (NTRS)

    Bates, H. E.; Hill, D. M.; Jewett, D. N.

    1983-01-01

    High-purity silicon efficiently produced and transferred by continuous two-cycle reactor. New reactor operates in relatively-narrow temperature rate and uses large surfaces area to minimize heat expenditure and processing time in producing silicon by hydrogen reduction of trichlorosilane. Two cycles of reactor consists of silicon production and removal.

  20. INFOODS guidelines for food matching

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is necessary to match food consumption data with food composition data in order to calculate estimates of nutrient intakes and dietary exposure. This can be done manually or through an automated system. As food matching procedures are key to obtaining high quality estimations of nutrient intake...

  1. InGaAlAsPN: A Materials System for Silicon Based Optoelectronics and Heterostructure Device Technologies

    NASA Technical Reports Server (NTRS)

    Broekaert, T. P. E.; Tang, S.; Wallace, R. M.; Beam, E. A., III; Duncan, W. M.; Kao, Y. -C.; Liu, H. -Y.

    1995-01-01

    A new material system is proposed for silicon based opto-electronic and heterostructure devices; the silicon lattice matched compositions of the (In,Ga,Al)-(As,P)N 3-5 compounds. In this nitride alloy material system, the bandgap is expected to be direct at the silicon lattice matched compositions with a bandgap range most likely to be in the infrared to visible. At lattice constants ranging between those of silicon carbide and silicon, a wider bandgap range is expected to be available and the high quality material obtained through lattice matching could enable applications such as monolithic color displays, high efficiency multi-junction solar cells, opto-electronic integrated circuits for fiber communications, and the transfer of existing 3-5 technology to silicon.

  2. Intensity of tennis match play

    PubMed Central

    Fernandez, J; Mendez‐Villanueva, A; Pluim, B M

    2006-01-01

    This review focuses on the characteristics of tennis players during match play and provides a greater insight into the energy demands of tennis. A tennis match often lasts longer than an hour and in some cases more than five hours. During a match there is a combination of periods of maximal or near maximal work and longer periods of moderate and low intensity activity. Match intensity varies considerably depending on the players' level, style, and sex. It is also influenced by factors such as court surface and ball type. This has important implications for the training of tennis players, which should resemble match intensity and include interval training with appropriate work to rest ratios. PMID:16632566

  3. Color matching in facial prosthetics: A systematic review.

    PubMed

    Ranabhatt, Rani; Singh, Kamleshwar; Siddharth, Ramashanker; Tripathi, Shuchi; Arya, Deeksha

    2017-01-01

    Color matching to the surrounding skin is extremely important in patients wearing maxillofacial prostheses. It is of utmost importance to know the different techniques of color matching and coloring in maxillofacial prostheses. The purpose of this study is to review the literature data with regard to color matching in maxillofacial prosthetics. An electronic search of peer review restricted to English language dental literature was conducted to identify the relevant scientific article on color matching and coloring in maxillofacial prostheses. The publication year was up to December 2015 so that the search could include all the articles provided in that particular database. Two independent observers independently read the abstracts and later preselected full-text articles. A full-text review was carried out only for 15 articles. Out of the 15 articles, 7 were related to coloring using tinting, spraying, milling, and use of commercial cosmetics. Three studies were related to shade matching in maxillofacial prostheses. Two studies conducted the measurement of color in maxillofacial prostheses. Only one study had explained color and its relevance in maxillofacial prosthetics. Only one study was done for reproducing silicone shade guide matching Indian skin color. In addition, a single pilot study was done to measure facial skin and lip color in a human population sample stratified by race, gender, and age. Currently, there is no evidence discussing the best technique available for perfectly matching the color for the fabrication of maxillofacial prostheses. However, the latest instruments such as spectrophotometer and colorimeters are believed to have improved efficiency in matching the color.

  4. Glass-silicon column

    DOEpatents

    Yu, Conrad M.

    2003-12-30

    A glass-silicon column that can operate in temperature variations between room temperature and about 450.degree. C. The glass-silicon column includes large area glass, such as a thin Corning 7740 boron-silicate glass bonded to a silicon wafer, with an electrode embedded in or mounted on glass of the column, and with a self alignment silicon post/glass hole structure. The glass/silicon components are bonded, for example be anodic bonding. In one embodiment, the column includes two outer layers of silicon each bonded to an inner layer of glass, with an electrode imbedded between the layers of glass, and with at least one self alignment hole and post arrangement. The electrode functions as a column heater, and one glass/silicon component is provided with a number of flow channels adjacent the bonded surfaces.

  5. Porous silicon gettering

    SciTech Connect

    Tsuo, Y.S.; Menna, P.; Al-Jassim, M.

    1995-08-01

    We have studied a novel extrinsic gettering method that utilizes the very large surface areas, produced by porous silicon etch on both front and back surfaces of the silicon wafer, as gettering sites. In this method, a simple and low-cost chemical etching is used to generate the porous silicon layers. Then, a high-flux solar furnace (HFSF) is used to provide high-temperature annealing and the required injection of silicon interstitials. The gettering sites, along with the gettered impurities, can be easily removed at the end the process. The porous silicon removal process consists of oxidizing the porous silicon near the end the gettering process followed by sample immersion in HF acid. Each porous silicon gettering process removes up to about 10 {mu}m of wafer thickness. This gettering process can be repeated so that the desired purity level is obtained.

  6. Contour matching by epipolar geometry

    NASA Astrophysics Data System (ADS)

    Hu, Mao-Lin; Zhang, Damin; Wei, Sui

    2003-09-01

    Matching features computed in images is an important process in multiview image analysis. When the motion between two images is large, the matching problem becomes very difficult. In this paper, we propose a contour matching algorithm based on geometric constraints. With the assumption that the contours are obtained from images taken from a moving camera with static scenes, we apply the epipolar constraint between two sets of contours and compute the corresponding points on the contours. From the initial epipolar constraints obtained from comer point matching, candidate contours are selected according to the epipolar geometry, the linear relation among tangent vectors of the contour. In order to reduce the possibility of false matches, the curvature of the contour of match points on a contour is also used as a selection method. The initial epipolar constraint is refined from the matched sets of contours. The algorithm can be applied to a pair or two pairs of images. All of the processes are fully automatic and successfully implemented and tested with various synthetic images.

  7. MATCHING IN INFORMAL FINANCIAL INSTITUTIONS

    PubMed Central

    Eeckhout, Jan; Munshi, Kaivan

    2013-01-01

    This paper analyzes an informal financial institution that brings heterogeneous agents together in groups. We analyze decentralized matching into these groups, and the equilibrium composition of participants that consequently arises. We find that participants sort remarkably well across the competing groups, and that they re-sort immediately following an unexpected exogenous regulatory change. These findings suggest that the competitive matching model might have applicability and bite in other settings where matching is an important equilibrium phenomenon. (JEL: O12, O17, G20, D40) PMID:24027491

  8. Matching Faces Against the Clock

    PubMed Central

    Fysh, Matthew; Cross, Katie; Watts, Rebecca

    2016-01-01

    This study examined the effect of time pressure on face-matching accuracy. Across two experiments, observers decided whether pairs of faces depict one person or different people. Time pressure was exerted via two additional displays, which were constantly updated to inform observers on whether they were on track to meet or miss a time target. In this paradigm, faces were matched under increasing or decreasing (Experiment 1) and constant time pressure (Experiment 2), which varied from 10 to 2 seconds. In both experiments, time pressure reduced accuracy, but the point at which this declined varied from 8 to 2 seconds. A separate match response bias was found, which developed over the course of the experiments. These results indicate that both time pressure and the repetitive nature of face matching are detrimental to performance. PMID:27757219

  9. Matching Network For Microwave Preamplifier

    NASA Technical Reports Server (NTRS)

    Sifri, Jack D.

    1988-01-01

    Stable operation and broadband, optimum noise performance achieved. Amplifier designed by new method of matching input impedance for optimum noise figure and stability. Output more nearly constant over wider frequency range.

  10. Designing self-matching linacs

    SciTech Connect

    Mills, R.S.; Crandall, K.R.; Farrell, J.A.

    1984-01-01

    The present trend in ion-linac design is to begin with a radio-frequency quadrupole (RFQ) linac followed by one or more drift-tube linac (DTL) tanks in which permanent-magnet quadrupoles are used for transverse focusing. The lack of adjustable elements (knobs) strongly suggests that one should seek linac designs with intertank matching solutions that are insensitive to beam currents and emittances, which can be accomplished if there are no sharp discontinuities in the focusing properties along the entire linac. Guidelines are presented for linac design and describe techniques for longitudinal as well as transverse matching between tanks. For a wide range of beam currents and emittances, a beam matched at the entrance to the RFQ should remain well matched throughout the entire linac.

  11. Matching games with partial information

    NASA Astrophysics Data System (ADS)

    Laureti, Paolo; Zhang, Yi-Cheng

    2003-06-01

    We analyze different ways of pairing agents in a bipartite matching problem, with regard to its scaling properties and to the distribution of individual “satisfactions”. Then we explore the role of partial information and bounded rationality in a generalized Marriage Problem, comparing the benefits obtained by self-searching and by a matchmaker. Finally we propose a modified matching game intended to mimic the way consumers’ information makes firms to enhance the quality of their products in a competitive market.

  12. Nanocrystalline silicon/amorphous silicon dioxide superlattices

    SciTech Connect

    Fauchet, P.M.; Tsybeskov, L.; Zacharias, M. |; Hirschman, K. |

    1998-12-31

    Thin layers made of densely packed silicon nanocrystals sandwiched between amorphous silicon dioxide layers have been manufactured and characterized. An amorphous silicon/amorphous silicon dioxide superlattice is first grown by CVD or RF sputtering. The a-Si layers are recrystallized in a two-step procedure (nucleation + growth) for form layers of nearly identical nanocrystals whose diameter is given by the initial a-Si layer thickness. The recrystallization is monitored using a variety of techniques, including TEM, X-Ray, Raman, and luminescence spectroscopies. When the a-Si layer thickness decreases (from 25 nm to 2.5 nm) or the a-SiO{sub 2} layer thickness increases (from 1.5 nm to 6 nm), the recrystallization temperature increases dramatically compared to that of a single a-Si film. The removal of the a-Si tissue present between the nanocrystals, the passivation of the nanocrystals, and their doping are discussed.

  13. Silicon germanium carbon heteroepitaxial growth on silicon

    NASA Astrophysics Data System (ADS)

    Mayer, James W.

    1993-10-01

    This project represents the initiation of band-gap engineering of Si-based devices at Arizona State University by James W. Mayer. While at Cornell, he directed the Microscience and Technology program supported by the Semiconductor Research Corporation. His Work on heteoepitaxy of SiGe on silicon convinced him that heteroepitaxy on Si was a viable technique for forming smaller band gap layers on silicon but the requirement was for larger energy-gap materials. In the fall of 1991, James Mayer visited Tom Picraux of Sandia National Laboratories and Clarence Tracy of Motorola Semiconductor Products to discuss the possibility of a joint program to investigate Silicon Germanium Carbon Heteroepitaxial Growth on Silicon. This represented a new research and development initiate for band gap engineering.

  14. Phase-matched second harmonic generation with on-chip GaN-on-Si microdisks

    NASA Astrophysics Data System (ADS)

    Roland, I.; Gromovyi, M.; Zeng, Y.; El Kurdi, M.; Sauvage, S.; Brimont, C.; Guillet, T.; Gayral, B.; Semond, F.; Duboz, J. Y.; de Micheli, M.; Checoury, X.; Boucaud, P.

    2016-09-01

    We demonstrate phase-matched second harmonic generation in gallium nitride on silicon microdisks. The microdisks are integrated with side-coupling bus waveguides in a two-dimensional photonic circuit. The second harmonic generation is excited with a continuous wave laser in the telecom band. By fabricating a series of microdisks with diameters varying by steps of 8 nm, we obtain a tuning of the whispering gallery mode resonances for the fundamental and harmonic waves. Phase matching is obtained when both resonances are matched with modes satisfying the conservation of orbital momentum, which leads to a pronounced enhancement of frequency conversion.

  15. Phase-matched second harmonic generation with on-chip GaN-on-Si microdisks

    PubMed Central

    Roland, I.; Gromovyi, M.; Zeng, Y.; El Kurdi, M.; Sauvage, S.; Brimont, C.; Guillet, T.; Gayral, B.; Semond, F.; Duboz, J. Y.; de Micheli, M.; Checoury, X.; Boucaud, P.

    2016-01-01

    We demonstrate phase-matched second harmonic generation in gallium nitride on silicon microdisks. The microdisks are integrated with side-coupling bus waveguides in a two-dimensional photonic circuit. The second harmonic generation is excited with a continuous wave laser in the telecom band. By fabricating a series of microdisks with diameters varying by steps of 8 nm, we obtain a tuning of the whispering gallery mode resonances for the fundamental and harmonic waves. Phase matching is obtained when both resonances are matched with modes satisfying the conservation of orbital momentum, which leads to a pronounced enhancement of frequency conversion. PMID:27687007

  16. Silicon Heat Pipe Array

    NASA Technical Reports Server (NTRS)

    Yee, Karl Y.; Ganapathi, Gani B.; Sunada, Eric T.; Bae, Youngsam; Miller, Jennifer R.; Beinsford, Daniel F.

    2013-01-01

    Improved methods of heat dissipation are required for modern, high-power density electronic systems. As increased functionality is progressively compacted into decreasing volumes, this need will be exacerbated. High-performance chip power is predicted to increase monotonically and rapidly with time. Systems utilizing these chips are currently reliant upon decades of old cooling technology. Heat pipes offer a solution to this problem. Heat pipes are passive, self-contained, two-phase heat dissipation devices. Heat conducted into the device through a wick structure converts the working fluid into a vapor, which then releases the heat via condensation after being transported away from the heat source. Heat pipes have high thermal conductivities, are inexpensive, and have been utilized in previous space missions. However, the cylindrical geometry of commercial heat pipes is a poor fit to the planar geometries of microelectronic assemblies, the copper that commercial heat pipes are typically constructed of is a poor CTE (coefficient of thermal expansion) match to the semiconductor die utilized in these assemblies, and the functionality and reliability of heat pipes in general is strongly dependent on the orientation of the assembly with respect to the gravity vector. What is needed is a planar, semiconductor-based heat pipe array that can be used for cooling of generic MCM (multichip module) assemblies that can also function in all orientations. Such a structure would not only have applications in the cooling of space electronics, but would have commercial applications as well (e.g. cooling of microprocessors and high-power laser diodes). This technology is an improvement over existing heat pipe designs due to the finer porosity of the wick, which enhances capillary pumping pressure, resulting in greater effective thermal conductivity and performance in any orientation with respect to the gravity vector. In addition, it is constructed of silicon, and thus is better

  17. 76 FR 5235 - Privacy Act of 1974, as Amended; Computer Matching Program (SSA Internal Match)-Match Number 1014

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-28

    ... ADMINISTRATION Privacy Act of 1974, as Amended; Computer Matching Program (SSA Internal Match)--Match Number 1014 AGENCY: Social Security Administration (SSA) ACTION: Notice of a new computer matching program. SUMMARY... computer matching program that we are conducting with ourselves. DATES: We will file a report of...

  18. Silicon on graphite cloth

    SciTech Connect

    Rand, J.A.; Cotter, J.E.; Thomas, C.J.; Ingram, A.E.; Bai, Y.B.; Ruffins, T.R.; Barnett, A.M.

    1994-12-31

    A new polycrystalline silicon solar cell has been developed that utilizes commercially available graphite cloth as a substrate. This solar cell has achieved an energy conversion efficiency of 13.4% (AM1.5G). It is believed that this is a record efficiency for a silicon solar cell formed on a graphite substrate. The silicon-on-fabric structure is comprised of a thin layer of polycrystalline silicon grown directly on the graphite fabric substrate. The structure is fabricated by a low-cost ribbon process that avoids the expense and waste of wafering. The fabric substrate gives structural support to the thin device. Critical to the achievement of device quality silicon layers is control over impurities in the graphite fabric. The silicon-on-fabric technology has the potential to supply lightweight, low-cost solar cells to weight-sensitive markets at a fraction of the cost of conventionally thinned wafers.

  19. Silicon micro-mold

    DOEpatents

    Morales, Alfredo M.

    2006-10-24

    The present invention describes a method for rapidly fabricating a robust 3-dimensional silicon-mold for use in preparing complex metal micro-components. The process begins by depositing a conductive metal layer onto one surface of a silicon wafer. A thin photoresist and a standard lithographic mask are then used to transfer a trace image pattern onto the opposite surface of the wafer by exposing and developing the resist. The exposed portion of the silicon substrate is anisotropically etched through the wafer thickness down to conductive metal layer to provide an etched pattern consisting of a series of rectilinear channels and recesses in the silicon which serve as the silicon micro-mold. Microcomponents are prepared with this mold by first filling the mold channels and recesses with a metal deposit, typically by electroplating, and then removing the silicon micro-mold by chemical etching.

  20. Growth of silicon bump induced by swift heavy ion at the silicon oxide-silicon interface

    SciTech Connect

    Carlotti, J.-F.; Touboul, A.D.; Ramonda, M.; Caussanel, M.; Guasch, C.; Bonnet, J.; Gasiot, J.

    2006-01-23

    Thin silicon oxide layers on silicon substrates are investigated by scanning probe microscopy before and after irradiation with 210 MeV Au+ ions. After irradiation and complete chemical etching of the silicon oxide layer, silicon bumps grown on the silicon surface are observed. It is shown that each impinging ion induces one silicon bump at the interface. This observation is consistent with the thermal spike theory. Ion energy loss is transferred to the oxide and induces local melting. Silicon-bump formation is favored when the oxide and oxide-silicon interface are silicon rich.

  1. Highly porous silicon membranes fabricated from silicon nitride/silicon stacks.

    PubMed

    Qi, Chengzhu; Striemer, Christopher C; Gaborski, Thomas R; McGrath, James L; Fauchet, Philippe M

    2014-07-23

    Nanopore formation in silicon films has previously been demonstrated using rapid thermal crystallization of ultrathin (15 nm) amorphous Si films sandwiched between nm-thick SiO2 layers. In this work, the silicon dioxide barrier layers are replaced with silicon nitride, resulting in nanoporous silicon films with unprecedented pore density and novel morphology. Four different thin film stack systems including silicon nitride/silicon/silicon nitride (NSN), silicon dioxide/silicon/silicon nitride (OSN), silicon nitride/silicon/silicon dioxide (NSO), and silicon dioxide/silicon/silicon dioxide (OSO) are tested under different annealing temperatures. Generally the pore size, pore density, and porosity positively correlate with the annealing temperature for all four systems. The NSN system yields substantially higher porosity and pore density than the OSO system, with the OSN and NSO stack characteristics fallings between these extremes. The higher porosity of the Si membrane in the NSN stack is primarily due to the pore formation enhancement in the Si film. It is hypothesized that this could result from the interfacial energy difference between the silicon/silicon nitride and silicon/silicon dioxide, which influences the Si crystallization process.

  2. SILICON CARBIDE FOR SEMICONDUCTORS

    DTIC Science & Technology

    This state-of-the-art survey on silicon carbide for semiconductors includes a bibliography of the most important references published as of the end...of 1964. The various methods used for growing silicon carbide single crystals are reviewed, as well as their properties and devices fabricated from...them. The fact that the state of-the-art of silicon carbide semiconductors is not further advanced may be attributed to the difficulties of growing

  3. Silicon Carbide Shapes.

    DTIC Science & Technology

    Free-standing silicon carbide shapes are produced by passing a properly diluted stream of a reactant gas, for example methyltrichlorosilane, into a...reaction chamber housing a thin walled, hollow graphite body heated to 1300-1500C. After the graphite body is sufficiently coated with silicon carbide , the...graphite body is fired, converting the graphite to gaseous CO2 and CO and leaving a silicon carbide shaped article remaining.

  4. The CDFII Silicon Detector

    SciTech Connect

    Julia Thom

    2004-07-23

    The CDFII silicon detector consists of 8 layers of double-sided silicon micro-strip sensors totaling 722,432 readout channels, making it one of the largest silicon detectors in present use by an HEP experiment. After two years of data taking, we report on our experience operating the complex device. The performance of the CDFII silicon detector is presented and its impact on physics analyses is discussed. We have already observed measurable effects from radiation damage. These results and their impact on the expected lifetime of the detector are briefly reviewed.

  5. Micromachined silicon electrostatic chuck

    DOEpatents

    Anderson, Robert A.; Seager, Carleton H.

    1996-01-01

    An electrostatic chuck is faced with a patterned silicon plate 11, created y micromachining a silicon wafer, which is attached to a metallic base plate 13. Direct electrical contact between the chuck face 15 (patterned silicon plate's surface) and the silicon wafer 17 it is intended to hold is prevented by a pattern of flat-topped silicon dioxide islands 19 that protrude less than 5 micrometers from the otherwise flat surface of the chuck face 15. The islands 19 may be formed in any shape. Islands may be about 10 micrometers in diameter or width and spaced about 100 micrometers apart. One or more concentric rings formed around the periphery of the area between the chuck face 15 and wafer 17 contain a low-pressure helium thermal-contact gas used to assist heat removal during plasma etching of a silicon wafer held by the chuck. The islands 19 are tall enough and close enough together to prevent silicon-to-silicon electrical contact in the space between the islands, and the islands occupy only a small fraction of the total area of the chuck face 15, typically 0.5 to 5 percent. The pattern of the islands 19, together with at least one hole 12 bored through the silicon veneer into the base plate, will provide sufficient gas-flow space to allow the distribution of the helium thermal-contact gas.

  6. Micromachined silicon electrostatic chuck

    DOEpatents

    Anderson, R.A.; Seager, C.H.

    1996-12-10

    An electrostatic chuck is faced with a patterned silicon plate, created by micromachining a silicon wafer, which is attached to a metallic base plate. Direct electrical contact between the chuck face (patterned silicon plate`s surface) and the silicon wafer it is intended to hold is prevented by a pattern of flat-topped silicon dioxide islands that protrude less than 5 micrometers from the otherwise flat surface of the chuck face. The islands may be formed in any shape. Islands may be about 10 micrometers in diameter or width and spaced about 100 micrometers apart. One or more concentric rings formed around the periphery of the area between the chuck face and wafer contain a low-pressure helium thermal-contact gas used to assist heat removal during plasma etching of a silicon wafer held by the chuck. The islands are tall enough and close enough together to prevent silicon-to-silicon electrical contact in the space between the islands, and the islands occupy only a small fraction of the total area of the chuck face, typically 0.5 to 5 percent. The pattern of the islands, together with at least one hole bored through the silicon veneer into the base plate, will provide sufficient gas-flow space to allow the distribution of the helium thermal-contact gas. 6 figs.

  7. Compounding with Silicones.

    PubMed

    Allen, Loyd V

    2015-01-01

    Since the 1940s, methylchlorosilanes have been used to treat glassware to prevent blood from clotting. The use of silicones in pharmaceutical and medical applications has grown to where today they are used in many life-saving devices (pacemakers, hydrocephalic shunts) and pharmaceutical applications from tubing, to excipients in topical formulations, to adhesives to affix transdermal drug delivery systems, and are also being used in products as active pharmaceutical ingredients, such as antiflatulents. About 60% of today's skin-care products now contain some type of silicone where they are considered safe and are known to provide a pleasant "silky-touch," non-greasy, and non-staining feel. Silicones exhibit many useful characteristics, and the safety of these agents supports their numerous applications; their biocompatibility is partially due to their low-chemical reactivity displayed by silicones, low-surface energy, and their hydrophobicity. Silicones are used both as active ingredients and as excipients. In addition is their use for "siliconization," or surface treatment, of many parenteral packaging components. Dimethicone and silicone oil are used as lubricants on stoppers to aid machineability, in syringes to aid piston movement, or on syringe needles to reduce pain upon injection. Silicones are also useful in pharmaceutical compounding as is discussed in this artiele included with this article are in developing formulations with silicones.

  8. Silicon web process development

    NASA Technical Reports Server (NTRS)

    Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Skutch, M. E.; Driggers, J. M.; Hopkins, R. H.

    1981-01-01

    The silicon web process takes advantage of natural crystallographic stabilizing forces to grow long, thin single crystal ribbons directly from liquid silicon. The ribbon, or web, is formed by the solidification of a liquid film supported by surface tension between two silicon filaments, called dendrites, which border the edges of the growing strip. The ribbon can be propagated indefinitely by replenishing the liquid silicon as it is transformed to crystal. The dendritic web process has several advantages for achieving low cost, high efficiency solar cells. These advantages are discussed.

  9. SILICON METABOLISM IN DIATOMS

    PubMed Central

    Lewin, Joyce C.

    1954-01-01

    1. Cells of the fresh water diatom Navicula pelliculosa may be grown in a mineral medium containing a low concentration of silicon. When transferred to a fresh silicate solution and incubated under non-growing conditions such deficient cells rapidly take up silicon from the medium. 2. The utilization of silicon is an aerobic process. 3. When deficient cells are washed with distilled water or saline, their ability to utilize silicon is impaired whereas respiration is unaffected. 4. The ability of washed cells to take up silicon can be partially restored with sulfate or ascorbic acid, and is completely restored by Na2S, Na2S2O3, glutathione, l-cysteine, dl-methionine, or ascorbic acid plus sulfate. 5. The sulfhydryl reagent, CdCl2, inhibits silicon utilization of unwashed cells at concentrations which do not affect respiration. This inhibition similarly is reversed by glutathione or cysteine. 6. However, sodium iodoacetate or sodium arsenite inhibits respiration and silicon utilization at the same concentrations. 7. The silicon taken up by deficient cells is deposited at the cell surface as a thickening of the existing silica frustules. 8. Sulfhydryl groups in the cell membrane may be involved in silicon uptake by diatoms. PMID:13163359

  10. Understanding Y haplotype matching probability.

    PubMed

    Brenner, Charles H

    2014-01-01

    The Y haplotype population-genetic terrain is better explored from a fresh perspective rather than by analogy with the more familiar autosomal ideas. For haplotype matching probabilities, versus for autosomal matching probabilities, explicit attention to modelling - such as how evolution got us where we are - is much more important while consideration of population frequency is much less so. This paper explores, extends, and explains some of the concepts of "Fundamental problem of forensic mathematics - the evidential strength of a rare haplotype match". That earlier paper presented and validated a "kappa method" formula for the evidential strength when a suspect matches a previously unseen haplotype (such as a Y-haplotype) at the crime scene. Mathematical implications of the kappa method are intuitive and reasonable. Suspicions to the contrary raised in rest on elementary errors. Critical to deriving the kappa method or any sensible evidential calculation is understanding that thinking about haplotype population frequency is a red herring; the pivotal question is one of matching probability. But confusion between the two is unfortunately institutionalized in much of the forensic world. Examples make clear why (matching) probability is not (population) frequency and why uncertainty intervals on matching probabilities are merely confused thinking. Forensic matching calculations should be based on a model, on stipulated premises. The model inevitably only approximates reality, and any error in the results comes only from error in the model, the inexactness of the approximation. Sampling variation does not measure that inexactness and hence is not helpful in explaining evidence and is in fact an impediment. Alternative haplotype matching probability approaches that various authors have considered are reviewed. Some are based on no model and cannot be taken seriously. For the others, some evaluation of the models is discussed. Recent evidence supports the adequacy of

  11. Block Matching for Object Tracking

    SciTech Connect

    Gyaourova, A; Kamath, C; Cheung, S

    2003-10-13

    Models which describe road traffic patterns can be helpful in detection and/or prevention of uncommon and dangerous situations. Such models can be built by the use of motion detection algorithms applied to video data. Block matching is a standard technique for encoding motion in video compression algorithms. We explored the capabilities of the block matching algorithm when applied for object tracking. The goal of our experiments is two-fold: (1) to explore the abilities of the block matching algorithm on low resolution and low frame rate video and (2) to improve the motion detection performance by the use of different search techniques during the process of block matching. Our experiments showed that the block matching algorithm yields good object tracking results and can be used with high success on low resolution and low frame rate video data. We observed that different searching methods have small effect on the final results. In addition, we proposed a technique based on frame history, which successfully overcame false motion caused by small camera movements.

  12. Matching illumination of solid objects.

    PubMed

    Pont, Sylvia C; Koenderink, Jan J

    2007-04-01

    The appearance of objects is determined by their surface reflectance and roughness and by the light field. Conversely, human observers might derive properties of the light field from the appearance of objects. The inverse problem has no unique solution, so perceptual interactions between reflectance, roughness, and lightfield are to be expected. In two separate experiments, we tested whether observers are able to match the illumination of spheres under collimated illumination only (matching of illumination direction) and under more or less diffuse illumination (matching of illumination direction and directedness of the beam). We found that observers are quite able to match collimated illumination directions of two rendered Lambertian spheres. Matching of the collimated beam directions of a Lambertian sphere and that of a real object with arbitrary reflectance and roughness properties resulted in similar results for the azimuthal angle, but in higher variance for the polar angle. Translucent objects and a tennis ball were found to be systematic outliers. If the directedness of the beam was also varied, the direction settings showed larger variance for more diffuse illumination. The directedness settings showed an overall quite large variance and, interestingly, interacted with the polar angle settings. We discuss possible photometrical mechanisms behind these effects.

  13. Path similarity skeleton graph matching.

    PubMed

    Bai, Xiang; Latecki, Longin Jan

    2008-07-01

    This paper presents a novel framework to for shape recognition based on object silhouettes. The main idea is to match skeleton graphs by comparing the shortest paths between skeleton endpoints. In contrast to typical tree or graph matching methods, we completely ignore the topological graph structure. Our approach is motivated by the fact that visually similar skeleton graphs may have completely different topological structures. The proposed comparison of shortest paths between endpoints of skeleton graphs yields correct matching results in such cases. The skeletons are pruned by contour partitioning with Discrete Curve Evolution, which implies that the endpoints of skeleton branches correspond to visual parts of the objects. The experimental results demonstrate that our method is able to produce correct results in the presence of articulations, stretching, and occlusion.

  14. Matching optics for Gaussian beams

    NASA Technical Reports Server (NTRS)

    Gunter, William D. (Inventor)

    1991-01-01

    A system of matching optics for Gaussian beams is described. The matching optics system is positioned between a light beam emitter (such as a laser) and the input optics of a second optics system whereby the output from the light beam emitter is converted into an optimum input for the succeeding parts of the second optical system. The matching optics arrangement includes the combination of a light beam emitter, such as a laser with a movable afocal lens pair (telescope) and a single movable lens placed in the laser's output beam. The single movable lens serves as an input to the telescope. If desired, a second lens, which may be fixed, is positioned in the beam before the adjustable lens to serve as an input processor to the movable lens. The system provides the ability to choose waist diameter and position independently and achieve the desired values with two simple adjustments not requiring iteration.

  15. Security and matching of partial fingerprint recognition systems

    NASA Astrophysics Data System (ADS)

    Jea, Tsai-Yang; Chavan, Viraj S.; Govindaraju, Venu; Schneider, John K.

    2004-08-01

    Despite advances in fingerprint identification techniques, matching incomplete or partial fingerprints still poses a difficult challenge. While the introduction of compact silicon chip-based sensors that capture only a part of the fingerprint area have made this problem important from a commercial perspective, there is also considerable interest on the topic for processing partial and latent fingerprints obtained at crime scenes. Attempts to match partial fingerprints using singular ridge structures-based alignment techniques fail when the partial print does not include such structures (e.g., core or delta). We present a multi-path fingerprint matching approach that utilizes localized secondary features derived using only the relative information of minutiae. Since the minutia-based fingerprint representation, is an ANSI-NIST standard, our approach has the advantage of being directly applicable to already existing databases. We also analyze the vulnerability of partial fingerprint identification systems to brute force attacks. The described matching approach has been tested on one of FVC2002"s DB1 database11. The experimental results show that our approach achieves an equal error rate of 1.25% and a total error rate of 1.8% (with FAR at 0.2% and FRR at 1.6%).

  16. Method and apparatus for stable silicon dioxide layers on silicon grown in silicon nitride ambient

    NASA Technical Reports Server (NTRS)

    Cohen, R. A.; Wheeler, R. K. (Inventor)

    1974-01-01

    A method and apparatus for thermally growing stable silicon dioxide layers on silicon is disclosed. A previously etched and baked silicon nitride tube placed in a furnace is used to grow the silicon dioxide. First, pure oxygen is allowed to flow through the tube to initially coat the inside surface of the tube with a thin layer of silicon dioxide. After the tube is coated with the thin layer of silicon dioxide, the silicon is oxidized thermally in a normal fashion. If the tube becomes contaminated, the silicon dioxide is etched off thereby exposing clean silicon nitride and then the inside of the tube is recoated with silicon dioxide. As is disclosed, the silicon nitride tube can also be used as the ambient for the pyrolytic decomposition of silane and ammonia to form thin layers of clean silicon nitride.

  17. Memristor-based pattern matching

    NASA Astrophysics Data System (ADS)

    Klimo, Martin; Such, Ondrej; Skvarek, Ondrej; Fratrik, Milan

    2014-10-01

    Pattern matching is a machine learning area that requires high-performance hardware. It has been hypothesized that massively parallel designs, which avoid von Neumann architecture, could provide a significant performance boost. Such designs can advantageously use memristive switches. This paper discusses a two-stage design that implements the induced ordered weighted average (IOWA) method for pattern matching. We outline the circuit structure and discuss how a functioning circuit can be achieved using metal oxide devices. We describe our simulations of memristive circuits and illustrate their performance on a vowel classification task.

  18. The beauty of match play.

    PubMed

    Clark, Russell D

    2006-06-01

    This study investigated whether higher seeded players have an advanage in the only match play event on the PGA Tour. Analysis showed that the higher seeded won 54% of the time (p=.06); the correlation was .17 (p<.01) between higher seeded players winning and the difference in World Rankings between players. Given professional golfers are at the highest end of the distribution of golf ability, these players are so nearly equal in ability, it is mainly a matter of chance who will win a match play event or who will have the best round on any given day.

  19. 7 CFR 2903.5 - Matching requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ..., DEPARTMENT OF AGRICULTURE BIODIESEL FUEL EDUCATION PROGRAM General Information § 2903.5 Matching requirements. There are no matching funds requirements for the Biodiesel Fuel Education Program and matching...

  20. 7 CFR 2903.5 - Matching requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ..., DEPARTMENT OF AGRICULTURE BIODIESEL FUEL EDUCATION PROGRAM General Information § 2903.5 Matching requirements. There are no matching funds requirements for the Biodiesel Fuel Education Program and matching...

  1. 7 CFR 2903.5 - Matching requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ..., DEPARTMENT OF AGRICULTURE BIODIESEL FUEL EDUCATION PROGRAM General Information § 2903.5 Matching requirements. There are no matching funds requirements for the Biodiesel Fuel Education Program and matching...

  2. 7 CFR 2903.5 - Matching requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ..., DEPARTMENT OF AGRICULTURE BIODIESEL FUEL EDUCATION PROGRAM General Information § 2903.5 Matching requirements. There are no matching funds requirements for the Biodiesel Fuel Education Program and matching...

  3. Relaxation matching algorithm for moving photogrammetry

    NASA Astrophysics Data System (ADS)

    Guo, Lei; Liu, Ke; Miao, Yinxiao; Zhu, Jigui

    2015-02-01

    Moving photogrammetry is an application of close range photogrammetry in industrial measurement to realize threedimensional coordinate measurement within large-scale volume. This paper describes an approach of relaxation matching algorithm applicable to moving photogrammetry according to the characteristics of accurate matching result of different measuring images. This method uses neighborhood matching support to improve the matching rate after coarse matching based on epipolar geometry constraint and precise matching using three images. It reflects the overall matching effect of all points, that means when a point is matched correctly, the matching results of those points round it must be correct. So for one point considered, the matching results of points round it are calculated to judge whether its result is correct. Analysis indicates that relaxation matching can eliminate the mismatching effectively and acquire 100% rate of correct matching. It will play a very important role in moving photogrammetry to ensure the following implement of ray bundle adjustment.

  4. 7 CFR 2903.5 - Matching requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., DEPARTMENT OF AGRICULTURE BIODIESEL FUEL EDUCATION PROGRAM General Information § 2903.5 Matching requirements. There are no matching funds requirements for the Biodiesel Fuel Education Program and matching...

  5. Parameter Estimation of a Spiking Silicon Neuron

    PubMed Central

    Russell, Alexander; Mazurek, Kevin; Mihalaş, Stefan; Niebur, Ernst; Etienne-Cummings, Ralph

    2012-01-01

    Spiking neuron models are used in a multitude of tasks ranging from understanding neural behavior at its most basic level to neuroprosthetics. Parameter estimation of a single neuron model, such that the model’s output matches that of a biological neuron is an extremely important task. Hand tuning of parameters to obtain such behaviors is a difficult and time consuming process. This is further complicated when the neuron is instantiated in silicon (an attractive medium in which to implement these models) as fabrication imperfections make the task of parameter configuration more complex. In this paper we show two methods to automate the configuration of a silicon (hardware) neuron’s parameters. First, we show how a Maximum Likelihood method can be applied to a leaky integrate and fire silicon neuron with spike induced currents to fit the neuron’s output to desired spike times. We then show how a distance based method which approximates the negative log likelihood of the lognormal distribution can also be used to tune the neuron’s parameters. We conclude that the distance based method is better suited for parameter configuration of silicon neurons due to its superior optimization speed. PMID:23852978

  6. Cleaning up Silicon

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A development program that started in 1975 between Union Carbide and JPL, led to Advanced Silicon Materials LLC's, formerly ASiMI, commercial process for producing silane in viable quantities. The process was expanded to include the production of high-purity polysilicon for electronic devices. The technology came out of JPL's Low Cost Silicon Array Project.

  7. Silicon carbide ceramic production

    NASA Technical Reports Server (NTRS)

    Suzuki, K.; Shinohara, N.

    1984-01-01

    A method to produce sintered silicon carbide ceramics in which powdery carbonaceous components with a dispersant are mixed with silicon carbide powder, shaped as required with or without drying, and fired in nonoxidation atmosphere is described. Carbon black is used as the carbonaceous component.

  8. Nonlinear silicon photonics

    NASA Astrophysics Data System (ADS)

    Tsia, Kevin K.; Jalali, Bahram

    2010-05-01

    An intriguing optical property of silicon is that it exhibits a large third-order optical nonlinearity, with orders-ofmagnitude larger than that of silica glass in the telecommunication band. This allows efficient nonlinear optical interaction at relatively low power levels in a small footprint. Indeed, we have witnessed a stunning progress in harnessing the Raman and Kerr effects in silicon as the mechanisms for enabling chip-scale optical amplification, lasing, and wavelength conversion - functions that until recently were perceived to be beyond the reach of silicon. With all the continuous efforts developing novel techniques, nonlinear silicon photonics is expected to be able to reach even beyond the prior achievements. Instead of providing a comprehensive overview of this field, this manuscript highlights a number of new branches of nonlinear silicon photonics, which have not been fully recognized in the past. In particular, they are two-photon photovoltaic effect, mid-wave infrared (MWIR) silicon photonics, broadband Raman effects, inverse Raman scattering, and periodically-poled silicon (PePSi). These novel effects and techniques could create a new paradigm for silicon photonics and extend its utility beyond the traditionally anticipated applications.

  9. Silicon Carbide Photoconductive Switches

    DTIC Science & Technology

    1994-09-01

    The optoelectronic properties of p-type 6-H silicon carbide (6H-SiC) have been investigated in an experiment that used lateral and vertical...and the bandgap was determined to be approximately 3.1 eV. 6H-SiC, Photoconductive, Photovoltaic, Absorption coefficient, Switch, Silicon carbide

  10. SILICON CARBIDE DATA SHEETS

    DTIC Science & Technology

    These data sheets present a compilation of a wide range of electrical, optical and energy values for alpha and beta- silicon carbide in bulk and film...spectrum. Energy data include energy bands, energy gap and energy levels for variously-doped silicon carbide , as well as effective mass tables, work

  11. Silicon Stokes terahertz laser

    SciTech Connect

    Pavlov, S. G.; Huebers, H.-W.; Hovenier, J. N.; Klaassen, T. O.; Carder, D. A.; Phillips, P. J.; Redlich, B.; Riemann, H.; Zhukavin, R. Kh.; Shastin, V. N.

    2007-04-10

    A Raman-type silicon laser at terahertz frequencies has been realized. Stokes-shifted stimulated emission has been observed from silicon crystals doped by antimony donors when optically excited by an infrared free electron laser. The Raman lasing was obtained due to resonant scattering on electronic states of a donor atom.

  12. Silicones in medical electronics.

    PubMed

    Bruner, Stephen

    2008-01-01

    The use of silicones, although already extensive, is set to grow in medical electronics. Silicones used in medical device applications as tubing or moulded parts should also be considered for electronic applications in the same device. This article outlines the potential reduction in complexity that this solution offers. Benefits include eliminating negative materials interactions and avoiding bonding problems.

  13. Microgravity silicon zoning investigation

    NASA Technical Reports Server (NTRS)

    Kern, E. L.; Gill, G. L., Jr.

    1983-01-01

    A resistance heated zoner, suitable for early zoning experiments with silicon, was designed and put into operation. The initial power usage and size was designed for an shown to be compatible with payload carriers contemplated for the Shuttle. This equipment will be used in the definition and development of flight experiments and apparatus for float zoning silicon and other materials in microgravity.

  14. Gate tunable graphene-silicon Ohmic/Schottky contacts

    NASA Astrophysics Data System (ADS)

    Chen, Chun-Chung; Chang, Chia-Chi; Li, Zhen; Levi, A. F. J.; Cronin, Stephen B.

    2012-11-01

    We show that the I-V characteristics of graphene-silicon junctions can be actively tuned from rectifying to Ohmic behavior by electrostatically doping the graphene with a polymer electrolyte gate. Under zero applied gate voltage, we observe rectifying I-V characteristics, demonstrating the formation of a Schottky junction at the graphene-silicon interface. Through appropriate gating, the Fermi energy of the graphene can be varied to match the conduction or valence band of silicon, thus forming Ohmic contacts with both n- and p-type silicon. Over the applied gate voltage range, the low bias conductance can be varied by more than three orders of magnitude. By varying the top gate voltage from -4 to +4 V, the Fermi energy of the graphene is shifted between -3.78 and -5.47 eV; a shift of ±0.85 eV from the charge neutrality point. Since the conduction and valence bands of the underlying silicon substrate lie within this range, at -4.01 and -5.13 eV, the Schottky barrier height and depletion width can be decreased to zero for both n- and p-type silicon under the appropriate top gating conditions. I-V characteristics taken under illumination show that the photo-induced current can be increased or decreased based on the graphene-silicon work function difference.

  15. A free interactive matching program

    SciTech Connect

    J.-F. Ostiguy

    1999-04-16

    For physicists and engineers involved in the design and analysis of beamlines (transfer lines or insertions) the lattice function matching problem is central and can be time-consuming because it involves constrained nonlinear optimization. For such problems convergence can be difficult to obtain in general without expert human intervention. Over the years, powerful codes have been developed to assist beamline designers. The canonical example is MAD (Methodical Accelerator Design) developed at CERN by Christophe Iselin. MAD, through a specialized command language, allows one to solve a wide variety of problems, including matching problems. Although in principle, the MAD command interpreter can be run interactively, in practice the solution of a matching problem involves a sequence of independent trial runs. Unfortunately, but perhaps not surprisingly, there still exists relatively few tools exploiting the resources offered by modern environments to assist lattice designer with this routine and repetitive task. In this paper, we describe a fully interactive lattice matching program, written in C++ and assembled using freely available software components. An important feature of the code is that the evolution of the lattice functions during the nonlinear iterative process can be graphically monitored in real time; the user can dynamically interrupt the iterations at will to introduce new variables, freeze existing ones into their current state and/or modify constraints. The program runs under both UNIX and Windows NT.

  16. Acceptable Ungrammaticality in Sentence Matching

    ERIC Educational Resources Information Center

    Duffield, Nigel; Matsuo, Ayumi; Roberts, Leah

    2007-01-01

    This article presents a new set of experiments using the "sentence-matching paradigm" (Forster, 1979; Freedman and Forster, 1985; see also Bley-Vroman and Masterson, 1989), investigating native speakers' and second language (L2) learners' knowledge of constraints on clitic placement in French. Our purpose is three-fold: (1) to shed more light on…

  17. Silicone-containing composition

    DOEpatents

    Mohamed, Mustafa

    2012-01-24

    A silicone-containing composition comprises the reaction product of a first component and an excess of an isocyanate component relative to the first component to form an isocyanated intermediary. The first component is selected from one of a polysiloxane and a silicone resin. The first component includes a carbon-bonded functional group selected from one of a hydroxyl group and an amine group. The isocyanate component is reactive with the carbon-bonded functional group of the first component. The isocyanated intermediary includes a plurality of isocyanate functional groups. The silicone-containing composition comprises the further reaction product of a second component, which is selected from the other of the polysiloxane and the silicone resin. The second component includes a plurality of carbon-bonded functional groups reactive with the isocyanate functional groups of the isocyanated intermediary for preparing the silicone-containing composition.

  18. Intraventricular Silicone Oil

    PubMed Central

    Mathis, Stéphane; Boissonnot, Michèle; Tasu, Jean-Pierre; Simonet, Charles; Ciron, Jonathan; Neau, Jean-Philippe

    2016-01-01

    Abstract Intracranial silicone oil is a rare complication of intraocular endotamponade with silicone oil. We describe a case of intraventricular silicone oil fortuitously observed 38 months after an intraocular tamponade for a complicated retinal detachment in an 82 year-old woman admitted in the Department of Neurology for a stroke. We confirm the migration of silicone oil along the optic nerve. We discuss this rare entity with a review of the few other cases reported in the medical literature. Intraventricular migration of silicone oil after intraocular endotamponade is usually asymptomatic but have to be known of the neurologists and the radiologists because of its differential diagnosis that are intraventricular hemorrhage and tumor. PMID:26735537

  19. Silicon Nanocrystal Laser

    SciTech Connect

    Yu, J

    2005-03-09

    The purpose of this feasibility study project was to attempt to demonstrate the silicon-nanocrystal-based laser. Such a silicon laser (made using conventional silicon-manufacturing technologies) would provide the crucial missing link that would enable a completely-silicon-based photonic system. We prepared thin layers of silicon nanocrystal material by ion-implanting Si in fused silica substrates, followed by a high temperature anneal process. These Si nanocrystals produced intense photoluminescence when optically pumped with ultraviolet light. Laser structures based on Fabry-Perot cavity and distributed feedback (DFB) designs were fabricated using the Si nanocrystals as the ''lasing'' medium. We optically pumped the samples with CW lasers at 413nm wavelength to quickly assess the feasibility of making lasers out of the Nanocrystal Si material and to verify the gain coefficients reported by other research groups.

  20. Reversible Cycling of Silicon and Silicon Alloys

    NASA Astrophysics Data System (ADS)

    Obrovac, Mark

    2012-02-01

    Lithium ion batteries typically use a graphite negative electrode. Silicon can store more lithium than any other element and has long been considered as an attractive replacement for graphite. The theoretical lithium storage capacity of silicon is nearly ten times higher than graphite volumetrically and three times higher gravimetrically. The equilibrium Si-Li binary system is well known. Completely new phase behaviors are observed at room temperature. This includes the formation of a new phase, Li15Si4, which is the highest lithium containing phase at room temperature [1]. The formation of Li15Si4 is accompanied by a 280 percent volume expansion of silicon. During de-alloying this phase contracts, forming amorphous silicon. The volume expansion of alloys can cause intra-particle fracture and inter-particle disconnection; leading to loss of cycle life. To overcome issues with volume expansion requires a detailed knowledge of Li-Si phase behavior, careful design of the composition and nanostructure of the alloy and the microstructure of the negative electrode [2]. In this presentation the phase behavior of the Li-Si system will be described. Using this knowledge alone, strategies can be developed so that silicon can be reversibly cycled in a battery hundreds of times. Further increases in energy density and efficiency can be gained by alloying silicon with other elements, while controlling microstructure [2]. Coupled with negative electrode design strategies, practical negative electrodes for lithium ion cells can be developed based on bulk materials, with significant energy density improvement over conventional electrodes. [4pt] [1] M.N. Obrovac and L.J. Krause, J. Electrochem. Soc., 154 (2007) A103. [0pt] [2] M.N. Obrovac, Leif Christensen, Dinh Ba Le, and J.R. Dahn, J. Electrochem. Soc., 154 (2007) A849

  1. Teflon bonding of silicon solar cells

    NASA Astrophysics Data System (ADS)

    White, P. A.; Jones, D. E.

    The silicon adhesive used to bond the coverglass onto the solar cell can be replaced by a thin layer of FEP Teflon. The advantage of using Teflon as the adhesive is that it is supplied as a thin sheet in thicknesses of 25 or 50 microns and can be cut to size prior to use. Because the Teflon does not extrude from the join in the same manner as conventional adhesives, the cleanup after Teflon bonding is virtually nonexistent. It is considered that the use of a coverglass which is thermally matched to silicon will prevent the buildup of thermal stresses which could cause delamination. Work done to date on the Teflon bonding process including the results of some critical end of life tests is reviewed.

  2. Structure, defects, and strain in silicon-silicon oxide interfaces

    SciTech Connect

    Kovačević, Goran Pivac, Branko

    2014-01-28

    The structure of the interfaces between silicon and silicon-oxide is responsible for proper functioning of MOSFET devices while defects in the interface can deteriorate this function and lead to their failure. In this paper we modeled this interface and characterized its defects and strain. MD simulations were used for reconstructing interfaces into a thermodynamically stable configuration. In all modeled interfaces, defects were found in the form of three-coordinated silicon atom, five coordinated silicon atom, threefold-coordinated oxygen atom, or displaced oxygen atom. Three-coordinated oxygen atom can be created if dangling bonds on silicon are close enough. The structure and stability of three-coordinated silicon atoms (P{sub b} defect) depend on the charge as well as on the electric field across the interface. The negatively charged P{sub b} defect is the most stable one, but the electric field resulting from the interface reduces that stability. Interfaces with large differences in periodic constants of silicon and silicon oxide can be stabilized by buckling of silicon layer. The mechanical stress resulted from the interface between silicon and silicon oxide is greater in the silicon oxide layer. Ab initio modeling of clusters representing silicon and silicon oxide shows about three time larger susceptibility to strain in silicon oxide than in silicon if exposed to the same deformation.

  3. Method for producing silicon nitride/silicon carbide composite

    DOEpatents

    Dunmead, Stephen D.; Weimer, Alan W.; Carroll, Daniel F.; Eisman, Glenn A.; Cochran, Gene A.; Susnitzky, David W.; Beaman, Donald R.; Nilsen, Kevin J.

    1996-07-23

    Silicon carbide/silicon nitride composites are prepared by carbothermal reduction of crystalline silica powder, carbon powder and optionally crsytalline silicon nitride powder. The crystalline silicon carbide portion of the composite has a mean number diameter less than about 700 nanometers and contains nitrogen.

  4. 78 FR 73195 - Privacy Act of 1974: CMS Computer Matching Program Match No. 2013-01; HHS Computer Matching...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-05

    ... HUMAN SERVICES Centers for Medicare & Medicaid Services Privacy Act of 1974: CMS Computer Matching Program Match No. 2013-01; HHS Computer Matching Program Match No. 1312 AGENCY: Centers for Medicare & Medicaid Services (CMS), Department of Health and Human Services (HHS). ACTION: Notice of Computer...

  5. Process for purification of silicon

    NASA Technical Reports Server (NTRS)

    Rath, H. J.; Sirtl, E.; Pfeiffer, W.

    1981-01-01

    The purification of metallurgically pure silicon having a silicon content of more than 95% by weight is accomplished by leaching with an acidic solution which substantially does not attack silicon. A mechanical treatment leading to continuous particle size reduction of the granulated silicon to be purified is combined with the chemical purification step.

  6. Transformational silicon electronics.

    PubMed

    Rojas, Jhonathan Prieto; Torres Sevilla, Galo Andres; Ghoneim, Mohamed Tarek; Inayat, Salman Bin; Ahmed, Sally M; Hussain, Aftab Mustansir; Hussain, Muhammad Mustafa

    2014-02-25

    In today's traditional electronics such as in computers or in mobile phones, billions of high-performance, ultra-low-power devices are neatly integrated in extremely compact areas on rigid and brittle but low-cost bulk monocrystalline silicon (100) wafers. Ninety percent of global electronics are made up of silicon. Therefore, we have developed a generic low-cost regenerative batch fabrication process to transform such wafers full of devices into thin (5 μm), mechanically flexible, optically semitransparent silicon fabric with devices, then recycling the remaining wafer to generate multiple silicon fabric with chips and devices, ensuring low-cost and optimal utilization of the whole substrate. We show monocrystalline, amorphous, and polycrystalline silicon and silicon dioxide fabric, all from low-cost bulk silicon (100) wafers with the semiconductor industry's most advanced high-κ/metal gate stack based high-performance, ultra-low-power capacitors, field effect transistors, energy harvesters, and storage to emphasize the effectiveness and versatility of this process to transform traditional electronics into flexible and semitransparent ones for multipurpose applications.

  7. Process for making silicon

    NASA Technical Reports Server (NTRS)

    Levin, Harry (Inventor)

    1987-01-01

    A reactor apparatus (10) adapted for continuously producing molten, solar grade purity elemental silicon by thermal reaction of a suitable precursor gas, such as silane (SiH.sub.4), is disclosed. The reactor apparatus (10) includes an elongated reactor body (32) having graphite or carbon walls which are heated to a temperature exceeding the melting temperature of silicon. The precursor gas enters the reactor body (32) through an efficiently cooled inlet tube assembly (22) and a relatively thin carbon or graphite septum (44). The septum (44), being in contact on one side with the cooled inlet (22) and the heated interior of the reactor (32) on the other side, provides a sharp temperature gradient for the precursor gas entering the reactor (32) and renders the operation of the inlet tube assembly (22) substantially free of clogging. The precursor gas flows in the reactor (32) in a substantially smooth, substantially axial manner. Liquid silicon formed in the initial stages of the thermal reaction reacts with the graphite or carbon walls to provide a silicon carbide coating on the walls. The silicon carbide coated reactor is highly adapted for prolonged use for production of highly pure solar grade silicon. Liquid silicon (20) produced in the reactor apparatus (10) may be used directly in a Czochralski or other crystal shaping equipment.

  8. Hydrogen in amorphous silicon

    SciTech Connect

    Peercy, P. S.

    1980-01-01

    The structural aspects of amorphous silicon and the role of hydrogen in this structure are reviewed with emphasis on ion implantation studies. In amorphous silicon produced by Si ion implantation of crystalline silicon, the material reconstructs into a metastable amorphous structure which has optical and electrical properties qualitatively similar to the corresponding properties in high-purity evaporated amorphous silicon. Hydrogen studies further indicate that these structures will accomodate less than or equal to 5 at.% hydrogen and this hydrogen is bonded predominantly in a monohydride (SiH/sub 1/) site. Larger hydrogen concentrations than this can be achieved under certain conditions, but the excess hydrogen may be attributed to defects and voids in the material. Similarly, glow discharge or sputter deposited amorphous silicon has more desirable electrical and optical properties when the material is prepared with low hydrogen concentration and monohydride bonding. Results of structural studies and hydrogen incorporation in amorphous silicon were discussed relative to the different models proposed for amorphous silicon.

  9. Roadmap on silicon photonics

    NASA Astrophysics Data System (ADS)

    Thomson, David; Zilkie, Aaron; Bowers, John E.; Komljenovic, Tin; Reed, Graham T.; Vivien, Laurent; Marris-Morini, Delphine; Cassan, Eric; Virot, Léopold; Fédéli, Jean-Marc; Hartmann, Jean-Michel; Schmid, Jens H.; Xu, Dan-Xia; Boeuf, Frédéric; O'Brien, Peter; Mashanovich, Goran Z.; Nedeljkovic, M.

    2016-07-01

    Silicon photonics research can be dated back to the 1980s. However, the previous decade has witnessed an explosive growth in the field. Silicon photonics is a disruptive technology that is poised to revolutionize a number of application areas, for example, data centers, high-performance computing and sensing. The key driving force behind silicon photonics is the ability to use CMOS-like fabrication resulting in high-volume production at low cost. This is a key enabling factor for bringing photonics to a range of technology areas where the costs of implementation using traditional photonic elements such as those used for the telecommunications industry would be prohibitive. Silicon does however have a number of shortcomings as a photonic material. In its basic form it is not an ideal material in which to produce light sources, optical modulators or photodetectors for example. A wealth of research effort from both academia and industry in recent years has fueled the demonstration of multiple solutions to these and other problems, and as time progresses new approaches are increasingly being conceived. It is clear that silicon photonics has a bright future. However, with a growing number of approaches available, what will the silicon photonic integrated circuit of the future look like? This roadmap on silicon photonics delves into the different technology and application areas of the field giving an insight into the state-of-the-art as well as current and future challenges faced by researchers worldwide. Contributions authored by experts from both industry and academia provide an overview and outlook for the silicon waveguide platform, optical sources, optical modulators, photodetectors, integration approaches, packaging, applications of silicon photonics and approaches required to satisfy applications at mid-infrared wavelengths. Advances in science and technology required to meet challenges faced by the field in each of these areas are also addressed together with

  10. Photometric invariant stereo matching method.

    PubMed

    Gu, Feifei; Zhao, Hong; Zhou, Xiang; Li, Jinjun; Bu, Penghui; Zhao, Zixin

    2015-12-14

    A robust stereo matching method based on a comprehensive mathematical model for color formation process is proposed to estimate the disparity map of stereo images with noise and photometric variations. The band-pass filter with DoP kernel is firstly used to filter out noise component of the stereo images. Then the log-chromaticity normalization process is applied to eliminate the influence of lightning geometry. All the other factors that may influence the color formation process are removed through the disparity estimation process with a specific matching cost. Performance of the developed method is evaluated by comparing with some up-to-date algorithms. Experimental results are presented to demonstrate the robustness and accuracy of the method.

  11. University Reactor Matching Grants Program

    SciTech Connect

    John Valentine; Farzad Rahnema; Said Abdel-Khalik

    2003-02-14

    During the 2002 Fiscal year, funds from the DOE matching grant program, along with matching funds from the industrial sponsors, have been used to support research in the area of thermal-hydraulics. Both experimental and numerical research projects have been performed. Experimental research focused on two areas: (1) Identification of the root cause mechanism for axial offset anomaly in pressurized water reactors under prototypical reactor conditions, and (2) Fluid dynamic aspects of thin liquid film protection schemes for inertial fusion reactor chambers. Numerical research focused on two areas: (1) Multi-fluid modeling of both two-phase and two-component flows for steam conditioning and mist cooling applications, and (2) Modeling of bounded Rayleigh-Taylor instability with interfacial mass transfer and fluid injection through a porous wall simulating the ''wetted wall'' protection scheme in inertial fusion reactor chambers. Details of activities in these areas are given.

  12. Propensity Score Matching: Retrospective Randomization?

    PubMed

    Jupiter, Daniel C

    Randomized controlled trials are viewed as the optimal study design. In this commentary, we explore the strength of this design and its complexity. We also discuss some situations in which these trials are not possible, or not ethical, or not economical. In such situations, specifically, in retrospective studies, we should make every effort to recapitulate the rigor and strength of the randomized trial. However, we could be faced with an inherent indication bias in such a setting. Thus, we consider the tools available to address that bias. Specifically, we examine matching and introduce and explore a new tool: propensity score matching. This tool allows us to group subjects according to their propensity to be in a particular treatment group and, in so doing, to account for the indication bias.

  13. 32 CFR 806b.50 - Computer matching.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 6 2011-07-01 2011-07-01 false Computer matching. 806b.50 Section 806b.50... PROGRAM Disclosing Records to Third Parties § 806b.50 Computer matching. Computer matching programs... on forms used in applying for benefits. Coordinate computer matching statements on forms with...

  14. 32 CFR 806b.50 - Computer matching.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Computer matching. 806b.50 Section 806b.50... PROGRAM Disclosing Records to Third Parties § 806b.50 Computer matching. Computer matching programs... on forms used in applying for benefits. Coordinate computer matching statements on forms with...

  15. 32 CFR 806b.50 - Computer matching.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 6 2014-07-01 2014-07-01 false Computer matching. 806b.50 Section 806b.50... PROGRAM Disclosing Records to Third Parties § 806b.50 Computer matching. Computer matching programs... on forms used in applying for benefits. Coordinate computer matching statements on forms with...

  16. 32 CFR 806b.50 - Computer matching.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 6 2012-07-01 2012-07-01 false Computer matching. 806b.50 Section 806b.50... PROGRAM Disclosing Records to Third Parties § 806b.50 Computer matching. Computer matching programs... on forms used in applying for benefits. Coordinate computer matching statements on forms with...

  17. DITEC: Technology Matching Tool (TMT)

    DTIC Science & Technology

    2016-08-01

    each sub-capability a numerical priority. (Figure 1) The User Requirement vectors tested were cybersecurity technology vectors, for this...Romero-Mariona, J. 2014. “DITEC (DoD-Centric and Independent Technology Evaluation Capability): A Process for Testing Security.” IEEE Seventh...TECHNICAL REPORT 3021 August 2016 DITEC Technology Matching Tool (TMT) Roger A. Hallman Braulio Coronado . Approved for public

  18. Segment-Based Stereo Matching

    DTIC Science & Technology

    1983-06-01

    N JIIU.J, IMlüliHM — o - SEGMENT-BASED STEREO MATCHING* By o Gerard G. Medioni and Ramakant Nevatia Intelligent Systems Group...industrial robotics. Stereo analysis provides a more direct quantitative depth evaluation than techniques such as shape from shad- ing, and its being...surveillance[Henderson79] and industrial robotics. Proposed solutions for the stereo problem follow a paradigm involving the following steps

  19. Matched witness for multipartite entanglement

    NASA Astrophysics Data System (ADS)

    Chen, Xiao-yu; Jiang, Li-zhen; Xu, Zhu-an

    2017-04-01

    Entanglement criteria for multipartite entangled states are obtained by matching witnesses to multipartite entangled states. The necessary and sufficient criterion of separability for three qubit X states is given as an example to illustrate the procedure of finding a criterion. The result is utilized to obtain the noise tolerance of W state. The necessary and sufficient criteria of three partite separability and full separability for four qubit noisy cluster states, three partite separability for four qubit noisy GHZ states are obtained.

  20. Template Matching on Parallel Architectures,

    DTIC Science & Technology

    1985-07-01

    memory. The processors run asynchronously. Thus according to Hynn’s categories the Butterfl . is a MIMD machine. The processors of the Butterfly are...Generalized Butterfly Architecture This section describes timings for pattern matching on the generalized Butterfl .. Ihe implementations on the Butterfly...these algorithms. Thus the best implementation of the techniques on the generalized Butterfl % are the same as the implementation on the real Butterfly

  1. Porous silicon gettering

    SciTech Connect

    Tsuo, Y.S.; Menna, P.; Pitts, J.R.

    1996-05-01

    The authors have studied a novel extrinsic gettering method that uses the large surface areas produced by a porous-silicon etch as gettering sites. The annealing step of the gettering used a high-flux solar furnace. They found that a high density of photons during annealing enhanced the impurity diffusion to the gettering sites. The authors used metallurgical-grade Si (MG-Si) prepared by directional solidification casing as the starting material. They propose to use porous-silicon-gettered MG-Si as a low-cost epitaxial substrate for polycrystalline silicon thin-film growth.

  2. Recrystallization of polycrystalline silicon

    NASA Technical Reports Server (NTRS)

    Lall, C.; Kulkarni, S. B.; Graham, C. D., Jr.; Pope, D. P.

    1981-01-01

    Optical metallography is used to investigate the recrystallization properties of polycrystalline semiconductor-grade silicon. It is found that polycrystalline silicon recrystallizes at 1380 C in relatively short times, provided that the prior deformation is greater than 30%. For a prior deformation of about 40%, the recrystallization process is essentially complete in about 30 minutes. Silicon recrystallizes at a substantially slower rate than metals at equivalent homologous temperatures. The recrystallized grain size is insensitive to the amount of prestrain for strains in the range of 10-50%.

  3. Matching: its acquisition and generalization.

    PubMed Central

    Crowley, Michael A; Donahoe, John W

    2004-01-01

    Choice typically is studied by exposing organisms to concurrent variable-interval schedules in which not only responses controlled by stimuli on the key are acquired but also switching responses and likely other operants as well. In the present research, discriminated key-pecking responses in pigeons were first acquired using a multiple schedule that minimized the reinforcement of switching operants. Then, choice was assessed during concurrent-probe periods in which pairs of discriminative stimuli were presented concurrently. Upon initial exposure to concurrently presented stimuli, choice approximated exclusive preference for the alternative associated with the higher reinforcement frequency. Concurrent schedules were then implemented that gave increasingly greater opportunities for switching operants to be conditioned. As these operants were acquired, the relation of relative response frequency to relative reinforcement frequency converged toward a matching relation. An account of matching with concurrent schedules is proposed in which responding exclusively to the discriminative stimulus associated with the higher reinforcement frequency declines as the concurrent stimuli become more similar and other operants-notably switching-are acquired and generalize to stimuli from both alternatives. The concerted effect of these processes fosters an approximate matching relation in commonly used concurrent procedures. PMID:15540502

  4. A Custom Made Intrinsic Silicone Shade Guide for Indian Population

    PubMed Central

    Behanam, Mohammed; Ahila, S.C.; Jei, J. Brintha

    2016-01-01

    Introduction Replication of natural skin colour in maxillofacial prosthesis has been traditionally done using trial and error method, as concrete shade guides are unavailable till date. Hence a novel custom made intrinsic silicone shade guide has been attempted for Indian population. Aim Reconstruction of maxillofacial defects is challenging, as achieving an aesthetic result is not always easy. A concoction of a novel intrinsic silicone shade guide was contemplated for the study and its reproducibility in clinical practice was analysed. Materials and Methods Medical grade room temperature vulcanising silicone was used for the fabrication of shade tabs. The shade guide consisted of three main groups I, II and III which were divided based upon the hues yellow, red and blue respectively. Five distinct intrinsic pigments were added in definite proportions to subdivide each group of different values from lighter to darker shades. A total number of 15 circular shade tabs comprised the guide. To validate the usage of the guide, visual assessment of colour matching was done by four investigators to investigate the consent of perfect colour correspondence. Data was statistically analysed using kappa coefficients. Results The kappa values were found to be 0.47 to 0.78 for yellow based group I, 0.13 to 0.65 for red based group II, and 0.07 to 0.36 for blue based group III. This revealed that the shade tabs of yellow and red based hues matched well and showed a statistically good colour matching. Conclusion This intrinsic silicone shade guide can be effectively utilised for fabrication of maxillofacial prosthesis with silicone in Indian population. A transparent colour formula with definite proportioning of intrinsic pigments is provided for obtaining an aesthetic match to skin tone. PMID:27190946

  5. Nanoscale thermal and thermoelectric transport in silicon

    NASA Astrophysics Data System (ADS)

    Ryu, Hyuk Ju

    Hotspots on microchips are a major challenge for the semiconductor industry. To understand heat conduction from hotspots on silicon, measurements of the thermal resistance and transfer function have been performed using patterned nanoheater/sensor pairs with width from 100 nm up to 5000 nm at temperature range of 30 ˜ 300 K. Calculations of the thermal resistance based on a simple thermal model, considering resistances by spreading, interface, and localized heating match with the measurements. The results reveal several important trends indicating the prevalence of localized heating or sub-continuum transport phenomena in the vicinity of a nanoscale hotspot. Thermoelectric cooling is a possible solution to cope with the hotspot issue. Silicon, in a nanostructured form, is an interesting thermoelectric material, because of significantly reduced thermal conductivity. However, further improvement in thermoelectric efficiency is highly desirable. Thermopower measurements of silicon nanoribbons with an integrated gate have been performed. The gate in the device is used to provide strong carrier confinement and enable tunability of the carrier density over a wide range, which is fully compatible with conventional silicon processing and microelectronics. It therefore offers a promising alternative to doping when considering the thermoelectric engineering of nanostructures. An enhancement of thermoelectric power factor has been observed in silicon nanoribbons. This enhancement can be understood by considering its behavior as a function of carrier density. We identify the underlying mechanisms for the power factor in the nanoribbon, which include quantum confinement, low scattering due to the absence of dopants, and, at low temperatures, a significant phonon drag contribution.

  6. Advanced silicon on insulator technology

    NASA Technical Reports Server (NTRS)

    Godbey, D.; Hughes, H.; Kub, F.

    1991-01-01

    Undoped, thin-layer silicon-on-insulator was fabricated using wafer bonding and selective etching techniques employing a molecular beam epitaxy (MBE) grown Si0.7Ge0.3 layer as an etch stop. Defect free, undoped 200-350 nm silicon layers over silicon dioxide are routinely fabricated using this procedure. A new selective silicon-germanium etch was developed that significantly improves the ease of fabrication of the bond and etch back silicon insulator (BESOI) material.

  7. Supercontinuum generation in silicon waveguides relying on wave-breaking.

    PubMed

    Castelló-Lurbe, David; Silvestre, Enrique

    2015-10-05

    Four-wave-mixing processes enabled during optical wave-breaking (OWB) are exploited in this paper for supercontinuum generation. Unlike conventional approaches based on OWB, phase-matching is achieved here for these nonlinear interactions, and, consequently, new frequency production becomes more efficient. We take advantage of this kind of pulse propagation to obtain numerically a coherent octave-spanning mid-infrared supercontinuum generation in a silicon waveguide pumping at telecom wavelengths in the normal dispersion regime. This scheme shows a feasible path to overcome limits imposed by two-photon absorption on spectral broadening in silicon waveguides.

  8. Silicon germanium semiconductive alloy and method of fabricating same

    NASA Technical Reports Server (NTRS)

    Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor)

    2008-01-01

    A silicon germanium (SiGe) semiconductive alloy is grown on a substrate of single crystalline Al.sub.2O.sub.3. A {111} crystal plane of a cubic diamond structure SiGe is grown on the substrate's {0001} C-plane such that a <110> orientation of the cubic diamond structure SiGe is aligned with a <1,0,-1,0> orientation of the {0001} C-plane. A lattice match between the substrate and the SiGe is achieved by using a SiGe composition that is 0.7223 atomic percent silicon and 0.2777 atomic percent germanium.

  9. Laser-induced incandescence from laser-heated silicon nanoparticles

    NASA Astrophysics Data System (ADS)

    Menser, Jan; Daun, Kyle; Dreier, Thomas; Schulz, Christof

    2016-11-01

    This work describes the application of temporally and spectrally resolved laser-induced incandescence to silicon nanoparticles synthesized in a microwave plasma reactor. Optical properties for bulk silicon presented in the literature were extended for nanostructured particles analyzed in this paper. Uncertainties of parameters in the evaporation submodel, as well as measurement noise, are incorporated into the inference process by Bayesian statistics. The inferred nanoparticle sizes agree with results from transmission electron microscopy, and the determined accommodation coefficient matches the values of the preceding study.

  10. Photoluminescence and electrical properties of silicon oxide and silicon nitride superlattices containing silicon nanocrystals

    NASA Astrophysics Data System (ADS)

    Shuleiko, D. V.; Ilin, A. S.

    2016-08-01

    Photoluminescence and electrical properties of superlattices with thin (1 to 5 nm) alternating silicon-rich silicon oxide or silicon-rich silicon nitride, and silicon oxide or silicon nitride layers containing silicon nanocrystals prepared by plasma-enhanced chemical vapor deposition with subsequent annealing were investigated. The entirely silicon oxide based superlattices demonstrated photoluminescence peak shift due to quantum confinement effect. Electrical measurements showed the hysteresis effect in the vicinity of zero voltage due to structural features of the superlattices from SiOa93/Si3N4 and SiN0.8/Si3N4 layers. The entirely silicon nitride based samples demonstrated resistive switching effect, comprising an abrupt conductivity change at about 5 to 6 V with current-voltage characteristic hysteresis. The samples also demonstrated efficient photoluminescence with maximum at ∼1.4 eV, due to exiton recombination in silicon nanocrystals.

  11. Porous silicon nanowires.

    PubMed

    Qu, Yongquan; Zhou, Hailong; Duan, Xiangfeng

    2011-10-05

    In this mini-review, we summarize recent progress in the synthesis, properties and applications of a new type of one-dimensional nanostructures-single crystalline porous silicon nanowires. The growth of porous silicon nanowires starting from both p- and n-type Si wafers with a variety of dopant concentrations can be achieved through either one-step or two-step reactions. The mechanistic studies indicate the dopant concentration of Si wafers, oxidizer concentration, etching time and temperature can affect the morphology of the as-etched silicon nanowires. The porous silicon nanowires are both optically and electronically active and have been explored for potential applications in diverse areas including photocatalysis, lithium ion batteries, gas sensors and drug delivery.

  12. Silicon production process evaluations

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Engineering design of the third distillation column in the process was accomplished. The initial design is based on a 94.35% recovery of dichlorosilane in the distillate and a 99.9% recovery of trichlorosilane in the bottoms. The specified separation is achieved at a reflux ratio of 15 with 20 trays (equilibrium stages). Additional specifications and results are reported including equipment size, temperatures and pressure. Specific raw material requirements necessary to produce the silicon in the process are presented. The primary raw materials include metallurgical grade silicon, silicon tetrachloride, hydrogen, copper (catalyst) and lime (waste treatment). Hydrogen chloride is produced as by product in the silicon deposition. Cost analysis of the process was initiated during this reporting period.

  13. Silicon microfabricated beam expander

    SciTech Connect

    Othman, A. Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A.; Ain, M. F.

    2015-03-30

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed.

  14. Silicone azide fireproof material

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Finely powdered titanium oxide was added to silicone azide as the sintering agent to produce a nonflammable material. Mixing proportions, physical properties, and chemical composition of the fireproofing material are included.

  15. Silicon production process evaluations

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The chemical engineering analysis of the preliminary process design of a process for producing solar cell grade silicon from dichlorosilane is presented. A plant to produce 1,000 MT/yr of silicon is analyzed. Progress and status for the plant design are reported for the primary activities of base case conditions (60 percent), reaction chemistry (50 percent), process flow diagram (35 percent), energy balance (10 percent), property data (10 percent) and equipment design (5 percent).

  16. Oxygen defect processes in silicon and silicon germanium

    SciTech Connect

    Chroneos, A.; Sgourou, E. N.; Londos, C. A.; Schwingenschlögl, U.

    2015-06-15

    Silicon and silicon germanium are the archetypical elemental and alloy semiconductor materials for nanoelectronic, sensor, and photovoltaic applications. The investigation of radiation induced defects involving oxygen, carbon, and intrinsic defects is important for the improvement of devices as these defects can have a deleterious impact on the properties of silicon and silicon germanium. In the present review, we mainly focus on oxygen-related defects and the impact of isovalent doping on their properties in silicon and silicon germanium. The efficacy of the isovalent doping strategies to constrain the oxygen-related defects is discussed in view of recent infrared spectroscopy and density functional theory studies.

  17. Colloidal characterization of ultrafine silicon carbide and silicon nitride powders

    NASA Technical Reports Server (NTRS)

    Whitman, Pamela K.; Feke, Donald L.

    1986-01-01

    The effects of various powder treatment strategies on the colloid chemistry of aqueous dispersions of silicon carbide and silicon nitride are examined using a surface titration methodology. Pretreatments are used to differentiate between the true surface chemistry of the powders and artifacts resulting from exposure history. Silicon nitride powders require more extensive pretreatment to reveal consistent surface chemistry than do silicon carbide powders. As measured by titration, the degree of proton adsorption from the suspending fluid by pretreated silicon nitride and silicon carbide powders can both be made similar to that of silica.

  18. High band gap 2-6 and 3-5 tunneling junctions for silicon multijunction solar cells

    NASA Technical Reports Server (NTRS)

    Daud, Taher (Inventor); Kachare, Akaram H. (Inventor)

    1986-01-01

    A multijunction silicon solar cell of high efficiency is provided by providing a tunnel junction between the solar cell junctions to connect them in series. The tunnel junction is comprised of p+ and n+ layers of high band gap 3-5 or 2-6 semiconductor materials that match the lattice structure of silicon, such as GaP (band gap 2.24 eV) or ZnS (band gap 3.6 eV). Each of which has a perfect lattice match with silicon to avoid defects normally associated with lattice mismatch.

  19. On the Conditional Matching of Fractal Networks

    NASA Astrophysics Data System (ADS)

    Wang, Yanchun; Sun, Weigang; Zhang, Jingyuan; Qin, Sen

    2016-12-01

    In this paper, we propose a new matching (called a conditional matching), where the condition refers to the matching of the new constructed network which includes all the nodes in the original network. We then enumerate the conditional matchings of the new network and prove that the number of conditional matchings is just the product of degree sequences of the original network. We choose two families of fractal networks to show our obtained results, including the pseudofractal network and Cayley tree. Finally, we calculate the entropy of the conditional matchings on the considered networks and see that the entropy of Cayley tree is smaller than that of the pseudofractal network.

  20. Hybrid Schema Matching for Deep Web

    NASA Astrophysics Data System (ADS)

    Chen, Kerui; Zuo, Wanli; He, Fengling; Chen, Yongheng

    Schema matching is the process of identifying semantic mappings, or correspondences, between two or more schemas. Schema matching is a first step and critical part of data integration. For schema matching of deep web, most researches only interested in query interface, while rarely pay attention to abundant schema information contained in query result pages. This paper proposed a mixed schema matching technique, which combines attributes that appeared in query structures and query results of different data sources, and mines the matched schemas inside. Experimental results prove the effectiveness of this method for improving the accuracy of schema matching.

  1. Hydrogenated amorphous silicon photonics

    NASA Astrophysics Data System (ADS)

    Narayanan, Karthik

    2011-12-01

    Silicon Photonics is quickly proving to be a suitable interconnect technology for meeting the future goals of on-chip bandwidth and low power requirements. However, it is not clear how silicon photonics will be integrated into CMOS chips, particularly microprocessors. The issue of integrating photonic circuits into electronic IC fabrication processes to achieve maximum flexibility and minimum complexity and cost is an important one. In order to minimize usage of chip real estate, it will be advantageous to integrate in three-dimensions. Hydrogenated amorphous silicon (a-Si:H) is emerging as a promising material for the 3-D integration of silicon photonics for on-chip optical interconnects. In addition, a-Si:H film can be deposited using CMOS compatible low temperature plasma-enhanced chemical vapor deposition (PECVD) process at any point in the fabrication process allowing maximum flexibility and minimal complexity. In this thesis, we demonstrate a-Si:H as a high performance alternate platform to crystalline silicon, enabling backend integration of optical interconnects in a hybrid photonic-electronic network-on-chip architecture. High quality passive devices are fabricated on a low-loss a-Si:H platform enabling wavelength division multiplexing schemes. We demonstrate a broadband all-optical modulation scheme based on free-carrier absorption effect, which can enable compact electro-optic modulators in a-Si:H. Furthermore, we comprehensively characterize the optical nonlinearities in a-Si:H and observe that a-Si:H exhibits enhanced nonlinearities as compared to crystalline silicon. Based on the enhanced nonlinearities, we demonstrate low-power four-wave mixing in a-Si:H waveguides enabling high speed all-optical devices in an a-Si:H platform. Finally, we demonstrate a novel data encoding scheme using thermal and all-optical tuning of silicon waveguides, increasing the spectral efficiency in an interconnect link.

  2. Micromachined silicon grisms for infrared optics.

    PubMed

    Mar, Douglas J; Marsh, Jasmina P; Deen, Casey P; Ling, Hao; Choo, Hosung; Jaffe, Daniel T

    2009-02-20

    We demonstrate the successful fabrication of large format (approximately 50 mm × 50 mm) gratings in monolithic silicon for use as high-efficiency grisms at infrared wavelengths. The substrates for the grisms were thick (8-16 mm) disks of precisely oriented single-crystal silicon (refractive index, n ~ 3.42). We used microlithography and chemical wet etching techniques to produce the diffraction gratings on one side of these substrates. These techniques permitted the manufacture of coarse grooves (as few as 7 grooves/mm) with precise control of the blaze angle and groove profile and resulted in excellent groove surface quality. Profilometric measurements of the groove structure of the gratings confirm that the physical dimensions of the final devices closely match their design values. Optical performance of these devices exceeds the specifications required for diffraction-limited performance (RMS wave surface error <λ/20) in the near- and mid-infrared (1-40 μm). Peak diffraction efficiencies measured in the reflection range from 70-95% of the theoretical maximum. Tests of our grisms in the near infrared indicate transmission efficiencies of 30-48% uncorrected for Fresnel losses and confirm excellent performance. In infrared wavelength regions where silicon transmits well, the blaze control and high index permit high-resolution, high-order dispersion in a compact space. The first application of these grisms is to provide FORCAST, a mid-infrared camera on NASA's airborne observatory, with a moderate resolution (R=100-1000) spectroscopic capability.

  3. Reducing the likelihood of long tennis matches.

    PubMed

    Barnett, Tristan; Alan, Brown; Pollard, Graham

    2006-01-01

    Long matches can cause problems for tournaments. For example, the starting times of subsequent matches can be substantially delayed causing inconvenience to players, spectators, officials and television scheduling. They can even be seen as unfair in the tournament setting when the winner of a very long match, who may have negative aftereffects from such a match, plays the winner of an average or shorter length match in the next round. Long matches can also lead to injuries to the participating players. One factor that can lead to long matches is the use of the advantage set as the fifth set, as in the Australian Open, the French Open and Wimbledon. Another factor is long rallies and a greater than average number of points per game. This tends to occur more frequently on the slower surfaces such as at the French Open. The mathematical method of generating functions is used to show that the likelihood of long matches can be substantially reduced by using the tiebreak game in the fifth set, or more effectively by using a new type of game, the 50-40 game, throughout the match. Key PointsThe cumulant generating function has nice properties for calculating the parameters of distributions in a tennis matchA final tiebreaker set reduces the length of matches as currently being used in the US OpenA new 50-40 game reduces the length of matches whilst maintaining comparable probabilities for the better player to win the match.

  4. Bond Angles in the Crystalline Silicon/Silicon Nitride Interface

    NASA Astrophysics Data System (ADS)

    Leonard, Robert H.; Bachlechner, Martina E.

    2006-03-01

    Silicon nitride deposited on a silicon substrate has major applications in both dielectric layers in microelectronics and as antireflection and passivation coatings in photovoltaic applications. Molecular dynamic simulations are performed to investigate the influence of temperature and rate of externally applied strain on the structural and mechanical properties of the silicon/silicon nitride interface. Bond-angles between various atom types in the system are used to find and understand more about the mechanisms leading to the failure of the crystal. Ideally in crystalline silicon nitride, bond angles of 109.5 occur when a silicon atom is at the vertex and 120 angles occur when a nitrogen atom is at the vertex. The comparison of the calculated angles to the ideal values give information on the mechanisms of failure in silicon/silicon nitride system.

  5. Very high temperature silicon on silicon pressure transducers

    NASA Technical Reports Server (NTRS)

    Kurtz, Anthony D.; Nunn, Timothy A.; Briggs, Stephen A.; Ned, Alexander

    1992-01-01

    A silicon on silicon pressure sensor has been developed for use at very high temperatures (1000 F). The design principles used to fabricate the pressure sensor are outlined and results are presented of its high temperature performance.

  6. Severe ASIA syndrome associated with lymph node, thoracic, and pulmonary silicone infiltration following breast implant rupture: experience with four cases.

    PubMed

    Nesher, G; Soriano, A; Shlomai, G; Iadgarov, Y; Shulimzon, T R; Borella, E; Dicker, D; Shoenfeld, Y

    2015-04-01

    Silicone has been considered biologically inert; thus it has been employed in many medical devices and nowadays is commonly used in plastic surgery for mammary prosthesis. It is well tolerated in most cases. However, autoimmune disorders and siliconomas with granulomatous reactions after silicone implant rupture have been described. We report cases of four women who developed systemic disorders following rupture of silicone breast implants resulting in lymph node and thoracic silicone infiltration. The symptoms in these cases, including arthralgia, myalgia, generalized weakness, severe fatigue, sleeping disturbances, cognitive impairment, memory loss, irritable bowel syndrome, and weight loss, clearly match the criteria of the recently defined autoimmune/inflammatory syndrome induced by adjuvants (ASIA).

  7. Robust feature point matching with sparse model.

    PubMed

    Jiang, Bo; Tang, Jin; Luo, Bin; Lin, Liang

    2014-12-01

    Feature point matching that incorporates pairwise constraints can be cast as an integer quadratic programming (IQP) problem. Since it is NP-hard, approximate methods are required. The optimal solution for IQP matching problem is discrete, binary, and thus sparse in nature. This motivates us to use sparse model for feature point matching problem. The main advantage of the proposed sparse feature point matching (SPM) method is that it generates sparse solution and thus naturally imposes the discrete mapping constraints approximately in the optimization process. Therefore, it can optimize the IQP matching problem in an approximate discrete domain. In addition, an efficient algorithm can be derived to solve SPM problem. Promising experimental results on both synthetic points sets matching and real-world image feature sets matching tasks show the effectiveness of the proposed feature point matching method.

  8. Research on Silicon, Carbon, and Silicon Carbide Heterostructures

    DTIC Science & Technology

    1990-09-14

    0Innr Jc9&9b 1. TITLE (Include Security Classification) Research on Silicon, Carbon, and Silicon Carbide Heterostructures Z. PERSONAL AUTHOR(S) W. D...and identify by block number) FIELD I GROUP SUB-GROUP PLASMAS. DEPOSITION. THIN FILMS. SILICON CARBIDE . DIAMOND. SURFACES. DESORPTION. CHARACTERIZATION...AND SILICON CARBIDE HETEROSTRUCTURES W. D. Partlow (P.I.), W. J. Choyke, J. T. Yates, Jr., C. C. Cheng, H. Gutleben, L. E. Kline, R. R. Mitchell, J

  9. Resistance after firing protected electric match

    DOEpatents

    Montoya, Arsenio P.

    1981-11-10

    An electric match having electrical leads embedded in flame-producing compound is protected against an accidental resistance across the leads after firing by a length of heat-shrinkable tubing encircling the match body and having a skirt portion extending beyond the leads. The heat of the burning match and an adjacent thermal battery causes the tubing to fold over the end of the match body, covering the ends of the leads and protecting them from molten pieces of the battery.

  10. Thick-film materials for silicon photovoltaic cell manufacture

    NASA Technical Reports Server (NTRS)

    Field, M. B.

    1977-01-01

    Thick film technology is applicable to three areas of silicon solar cell fabrication; metallization, junction formation, and coating for protection of screened ohmic contacts, particularly wrap around contacts, interconnection and environmental protection. Both material and process parameters were investigated. Printed ohmic contacts on n- and p-type silicon are very sensitive to the processing parameters of firing time, temperature, and atmosphere. Wrap around contacts are easily achieved by first printing and firing a dielectric over the edge and subsequently applying a low firing temperature conductor. Interconnection of cells into arrays can be achieved by printing and cofiring thick film metal pastes, soldering, or with heat curing conductive epoxies on low cost substrates. Printed (thick) film vitreous protection coatings do not yet offer sufficient optical uniformity and transparency for use on silicon. A sprayed, heat curable SiO2 based resin shows promise of providing both optical matching and environmental protection.

  11. Robust matching for voice recognition

    NASA Astrophysics Data System (ADS)

    Higgins, Alan; Bahler, L.; Porter, J.; Blais, P.

    1994-10-01

    This paper describes an automated method of comparing a voice sample of an unknown individual with samples from known speakers in order to establish or verify the individual's identity. The method is based on a statistical pattern matching approach that employs a simple training procedure, requires no human intervention (transcription, work or phonetic marketing, etc.), and makes no assumptions regarding the expected form of the statistical distributions of the observations. The content of the speech material (vocabulary, grammar, etc.) is not assumed to be constrained in any way. An algorithm is described which incorporates frame pruning and channel equalization processes designed to achieve robust performance with reasonable computational resources. An experimental implementation demonstrating the feasibility of the concept is described.

  12. Ontology Matching with Semantic Verification

    PubMed Central

    Jean-Mary, Yves R.; Shironoshita, E. Patrick; Kabuka, Mansur R.

    2009-01-01

    ASMOV (Automated Semantic Matching of Ontologies with Verification) is a novel algorithm that uses lexical and structural characteristics of two ontologies to iteratively calculate a similarity measure between them, derives an alignment, and then verifies it to ensure that it does not contain semantic inconsistencies. In this paper, we describe the ASMOV algorithm, and then present experimental results that measure its accuracy using the OAEI 2008 tests, and that evaluate its use with two different thesauri: WordNet, and the Unified Medical Language System (UMLS). These results show the increased accuracy obtained by combining lexical, structural and extensional matchers with semantic verification, and demonstrate the advantage of using a domain-specific thesaurus for the alignment of specialized ontologies. PMID:20186256

  13. Group-velocity-matched optical parametric oscillator in tilted quasi-phase-matched gratings.

    PubMed

    Zhang, Wei Quan

    2006-07-10

    An achromatic phase-matching scheme is reported for an optical parametric oscillator in tilted quasi-phase-matched gratings. The spectral angular dispersion is introduced in interaction waves such that each wave component satisfies the two-dimensional (noncollinear) quasi-phase matching. This is equivalent to simultaneous quasi-phase matching and group-velocity matching for ultrashort pulses. The phase-matching bandwidth for 10 mm periodically poled KTP increases by a factor of 12 at lambdas = 1.7 microm compared with one-dimensional quasi-phase matching. The effective interaction length will increase as a result of the matching.

  14. Matching and conditioned reinforcement rate.

    PubMed

    Shahan, Timothy A; Podlesnik, Christopher A; Jimenez-Gomez, Corina

    2006-03-01

    Attempts to examine the effects of variations in relative conditioned reinforcement rate on choice have been confounded by changes in rates of primary reinforcement or changes in the value of the conditioned reinforcer. To avoid these problems, this experiment used concurrent observing responses to examine sensitivity of choice to relative conditioned reinforcement rate. In the absence of observing responses, unsignaled periods of food delivery on a variable-interval 90-s schedule alternated with extinction on a center key (i.e., a mixed schedule was in effect). Two concurrently available observing responses produced 15-s access to a stimulus differentially associated with the schedule of food delivery (S+). The relative rate of S+ deliveries arranged by independent variable-interval schedules for the two observing responses varied across conditions. The relation between the ratio of observing responses and the ratio of S+ deliveries was well described by the generalized matching law, despite the absence of changes in the rate of food delivery. In addition, the value of the S+ deliveries likely remained constant across conditions because the ratio of S+ to mixed schedule food deliveries remained constant. Assuming that S+ deliveries serve as conditioned reinforcers, these findings are consistent with the functional similarity between primary and conditioned reinforcers suggested by general choice theories based on the concatenated matching law (e.g., contextual choice and hyperbolic value-added models). These findings are inconsistent with delay reduction theory, which has no terms for the effects of rate of conditioned reinforcement in the absence of changes in rate of primary reinforcement.

  15. 7 CFR 3405.5 - Matching funds.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Matching funds. 3405.5 Section 3405.5 Agriculture Regulations of the Department of Agriculture (Continued) COOPERATIVE STATE RESEARCH, EDUCATION, AND EXTENSION... Matching funds. Each application must provide for matching support from a non-Federal source. CSREES...

  16. 13 CFR 102.40 - Computer matching.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 13 Business Credit and Assistance 1 2011-01-01 2011-01-01 false Computer matching. 102.40 Section... Protection of Privacy and Access to Individual Records Under the Privacy Act of 1974 § 102.40 Computer matching. The OCIO will enforce the computer matching provisions of the Privacy Act. The FOI/PA Office...

  17. 39 CFR 266.10 - Computer matching.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Computer matching. 266.10 Section 266.10 Postal... Computer matching. (a) General. Any agency or Postal Service component that wishes to use records from a... records must submit its proposal to the Postal Service Manager Records Office. Computer matching...

  18. 39 CFR 266.10 - Computer matching.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 39 Postal Service 1 2011-07-01 2011-07-01 false Computer matching. 266.10 Section 266.10 Postal... Computer matching. (a) General. Any agency or Postal Service component that wishes to use records from a... records must submit its proposal to the Postal Service Manager Records Office. Computer matching...

  19. 13 CFR 102.40 - Computer matching.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Computer matching. 102.40 Section... Protection of Privacy and Access to Individual Records Under the Privacy Act of 1974 § 102.40 Computer matching. The OCIO will enforce the computer matching provisions of the Privacy Act. The FOI/PA Office...

  20. 13 CFR 102.40 - Computer matching.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 13 Business Credit and Assistance 1 2013-01-01 2013-01-01 false Computer matching. 102.40 Section... Protection of Privacy and Access to Individual Records Under the Privacy Act of 1974 § 102.40 Computer matching. The OCIO will enforce the computer matching provisions of the Privacy Act. The FOI/PA Office...

  1. 39 CFR 266.10 - Computer matching.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 39 Postal Service 1 2014-07-01 2014-07-01 false Computer matching. 266.10 Section 266.10 Postal... Computer matching. (a) General. Any agency or Postal Service component that wishes to use records from a... records must submit its proposal to the Postal Service Manager Records Office. Computer matching...

  2. 39 CFR 266.10 - Computer matching.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 39 Postal Service 1 2013-07-01 2013-07-01 false Computer matching. 266.10 Section 266.10 Postal... Computer matching. (a) General. Any agency or Postal Service component that wishes to use records from a... records must submit its proposal to the Postal Service Manager Records Office. Computer matching...

  3. 13 CFR 102.40 - Computer matching.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 13 Business Credit and Assistance 1 2012-01-01 2012-01-01 false Computer matching. 102.40 Section... Protection of Privacy and Access to Individual Records Under the Privacy Act of 1974 § 102.40 Computer matching. The OCIO will enforce the computer matching provisions of the Privacy Act. The FOI/PA Office...

  4. 39 CFR 266.10 - Computer matching.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 39 Postal Service 1 2012-07-01 2012-07-01 false Computer matching. 266.10 Section 266.10 Postal... Computer matching. (a) General. Any agency or Postal Service component that wishes to use records from a... records must submit its proposal to the Postal Service Manager Records Office. Computer matching...

  5. 13 CFR 102.40 - Computer matching.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 13 Business Credit and Assistance 1 2014-01-01 2014-01-01 false Computer matching. 102.40 Section... Protection of Privacy and Access to Individual Records Under the Privacy Act of 1974 § 102.40 Computer matching. The OCIO will enforce the computer matching provisions of the Privacy Act. The FOI/PA Office...

  6. Image Matching Using Generalized Hough Transforms

    NASA Technical Reports Server (NTRS)

    Davis, L. S.; Hu, F. P.; Hwang, V.; Kitchen, L.

    1983-01-01

    An image matching system specifically designed to match dissimilar images is described. A set of blobs and ribbons is first extracted from each image, and then generalized Hough transform techniques are used to match these sets and compute the transformation that best registers the image. An example of the application of the approach to one pair of remotely sensed images is presented.

  7. Database crime to crime match rate calculation.

    PubMed

    Buckleton, John; Bright, Jo-Anne; Walsh, Simon J

    2009-06-01

    Guidance exists on how to count matches between samples in a crime sample database but we are unable to locate a definition of how to estimate a match rate. We propose a method that does not proceed from the match counting definition but which has a strong logic.

  8. 24 CFR 92.221 - Match credit.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 1 2011-04-01 2011-04-01 false Match credit. 92.221 Section 92.221... INVESTMENT PARTNERSHIPS PROGRAM Program Requirements Matching Contribution Requirement § 92.221 Match credit. (a) When credit is given. Contributions are credited on a fiscal year basis at the time...

  9. 24 CFR 92.221 - Match credit.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 1 2014-04-01 2014-04-01 false Match credit. 92.221 Section 92.221... INVESTMENT PARTNERSHIPS PROGRAM Program Requirements Matching Contribution Requirement § 92.221 Match credit. (a) When credit is given. Contributions are credited on a fiscal year basis at the time...

  10. 24 CFR 92.221 - Match credit.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 1 2013-04-01 2013-04-01 false Match credit. 92.221 Section 92.221... INVESTMENT PARTNERSHIPS PROGRAM Program Requirements Matching Contribution Requirement § 92.221 Match credit. (a) When credit is given. Contributions are credited on a fiscal year basis at the time...

  11. 24 CFR 92.221 - Match credit.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Match credit. 92.221 Section 92.221... INVESTMENT PARTNERSHIPS PROGRAM Program Requirements Matching Contribution Requirement § 92.221 Match credit. (a) When credit is given. Contributions are credited on a fiscal year basis at the time...

  12. 24 CFR 92.221 - Match credit.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 1 2012-04-01 2012-04-01 false Match credit. 92.221 Section 92.221... INVESTMENT PARTNERSHIPS PROGRAM Program Requirements Matching Contribution Requirement § 92.221 Match credit. (a) When credit is given. Contributions are credited on a fiscal year basis at the time...

  13. 13 CFR 130.450 - Matching funds.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... in the budget proposal. Cash sources shall be identified by name and account. All applicants must... received by the SBDC during the budget period, as long as the total Cash Match provided by the SBDC is 50... to the total amount of SBA funding. At least 50% of the Matching Funds must be Cash Match....

  14. 7 CFR 3430.1006 - Matching requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... matching requirement does not apply to fundamental research (as defined in § 3430.2). (2) Special matching provisions for applied research. With prior approval by the NIFA authorized departmental officer (ADO), the Center or Subcenter may reduce or eliminate the matching requirement for applied research (as defined...

  15. Bondability of RTV silicon rubber

    NASA Technical Reports Server (NTRS)

    Delollis, N. J.; Montoya, O.

    1972-01-01

    Glow discharge method for producing a bondable Room Temperature Vulcanizing (RTV) silicone is described. Mechanical and chemical properties of silicone specimens are described. Theory concerning the relationship between surface characteristics and bondability is examined with respect to the polymer specimen.

  16. Bond Sensitivity to Silicone Contamination

    NASA Technical Reports Server (NTRS)

    Caldwell, G. A.; Hudson, W. D.; Hudson, W. D.; Cash, Stephen F. (Technical Monitor)

    2003-01-01

    Currently during fabrication of the Space Shuttle booster rocket motors, the use of silicone and silicone-containing products is prohibited in most applications. Many shop aids and other materials containing silicone have the potential, if they make contact with a bond surface, to transfer some of the silicone to the substrates being bonded. Such transfer could result in a reduction of the bond strength or even failure of the subsequent bonds. This concern is driving the need to understand the effect of silicones and the concentration needed to affect a given bond-line strength. Additionally, as silicone detection methods used for materials acceptance improve what may have gone unnoticed earlier is now being detected. Thus, realistic silicone limits for process materials (below which bond performance is satisfactory) are needed rather than having an absolute no silicone permitted policy.

  17. The electrophotonic silicon biosensor

    PubMed Central

    Juan-Colás, José; Parkin, Alison; Dunn, Katherine E.; Scullion, Mark G.; Krauss, Thomas F.; Johnson, Steven D.

    2016-01-01

    The emergence of personalized and stratified medicine requires label-free, low-cost diagnostic technology capable of monitoring multiple disease biomarkers in parallel. Silicon photonic biosensors combine high-sensitivity analysis with scalable, low-cost manufacturing, but they tend to measure only a single biomarker and provide no information about their (bio)chemical activity. Here we introduce an electrochemical silicon photonic sensor capable of highly sensitive and multiparameter profiling of biomarkers. Our electrophotonic technology consists of microring resonators optimally n-doped to support high Q resonances alongside electrochemical processes in situ. The inclusion of electrochemical control enables site-selective immobilization of different biomolecules on individual microrings within a sensor array. The combination of photonic and electrochemical characterization also provides additional quantitative information and unique insight into chemical reactivity that is unavailable with photonic detection alone. By exploiting both the photonic and the electrical properties of silicon, the sensor opens new modalities for sensing on the microscale. PMID:27624590

  18. Neuromorphic Silicon Neuron Circuits

    PubMed Central

    Indiveri, Giacomo; Linares-Barranco, Bernabé; Hamilton, Tara Julia; van Schaik, André; Etienne-Cummings, Ralph; Delbruck, Tobi; Liu, Shih-Chii; Dudek, Piotr; Häfliger, Philipp; Renaud, Sylvie; Schemmel, Johannes; Cauwenberghs, Gert; Arthur, John; Hynna, Kai; Folowosele, Fopefolu; Saighi, Sylvain; Serrano-Gotarredona, Teresa; Wijekoon, Jayawan; Wang, Yingxue; Boahen, Kwabena

    2011-01-01

    Hardware implementations of spiking neurons can be extremely useful for a large variety of applications, ranging from high-speed modeling of large-scale neural systems to real-time behaving systems, to bidirectional brain–machine interfaces. The specific circuit solutions used to implement silicon neurons depend on the application requirements. In this paper we describe the most common building blocks and techniques used to implement these circuits, and present an overview of a wide range of neuromorphic silicon neurons, which implement different computational models, ranging from biophysically realistic and conductance-based Hodgkin–Huxley models to bi-dimensional generalized adaptive integrate and fire models. We compare the different design methodologies used for each silicon neuron design described, and demonstrate their features with experimental results, measured from a wide range of fabricated VLSI chips. PMID:21747754

  19. Crystalline oxides on silicon.

    PubMed

    Reiner, James W; Kolpak, Alexie M; Segal, Yaron; Garrity, Kevin F; Ismail-Beigi, Sohrab; Ahn, Charles H; Walker, Fred J

    2010-07-20

    This review outlines developments in the growth of crystalline oxides on the ubiquitous silicon semiconductor platform. The overall goal of this endeavor is the integration of multifunctional complex oxides with advanced semiconductor technology. Oxide epitaxy in materials systems achieved through conventional deposition techniques is described first, followed by a description of the science and technology of using atomic layer-by-layer deposition with molecular beam epitaxy (MBE) to systematically construct the oxide-silicon interface. An interdisciplinary approach involving MBE, advanced real-space structural characterization, and first-principles theory has led to a detailed understanding of the process by which the interface between crystalline oxides and silicon forms, the resulting structure of the interface, and the link between structure and functionality. Potential applications in electronics and photonics are also discussed.

  20. Microgravity silicon zoning investigation

    NASA Technical Reports Server (NTRS)

    Kern, E. L.; Gill, G. L., Jr.

    1985-01-01

    The flow instabilities in floating zones of silicon were investigated and methods for investigation of these instabilities in microgravity were defined. Three principal tasks were involved: (1) characterization of the float zone in small diameter rods; (2) investigation of melt flow instabilities in circular melts in silicon disks; and (3) the development of a prototype of an apparatus that could be used in near term space experiments to investigate flow instabilities in a molten zone. It is shown that in a resistance heated zoner with 4 to 7 mm diameter silicon rods that the critical Marangoni number is about 1480 compared to a predicted value of 14 indicative that viable space experiments might be performed. The prototype float zone apparatus is built and specifications are prepared for a flight zoner should a decision be reached to proceed with a space flight experimental investigation.

  1. The electrophotonic silicon biosensor

    NASA Astrophysics Data System (ADS)

    Juan-Colás, José; Parkin, Alison; Dunn, Katherine E.; Scullion, Mark G.; Krauss, Thomas F.; Johnson, Steven D.

    2016-09-01

    The emergence of personalized and stratified medicine requires label-free, low-cost diagnostic technology capable of monitoring multiple disease biomarkers in parallel. Silicon photonic biosensors combine high-sensitivity analysis with scalable, low-cost manufacturing, but they tend to measure only a single biomarker and provide no information about their (bio)chemical activity. Here we introduce an electrochemical silicon photonic sensor capable of highly sensitive and multiparameter profiling of biomarkers. Our electrophotonic technology consists of microring resonators optimally n-doped to support high Q resonances alongside electrochemical processes in situ. The inclusion of electrochemical control enables site-selective immobilization of different biomolecules on individual microrings within a sensor array. The combination of photonic and electrochemical characterization also provides additional quantitative information and unique insight into chemical reactivity that is unavailable with photonic detection alone. By exploiting both the photonic and the electrical properties of silicon, the sensor opens new modalities for sensing on the microscale.

  2. Scriber for silicon wafers

    NASA Technical Reports Server (NTRS)

    Yamakawa, K. A.; Fortier, E. P. (Inventor)

    1981-01-01

    A device for dividing silicon wafers into rectangular chips is characterized by a base including a horizontally oriented bed with a planar support surface, a vacuum chuck adapted to capture a silicon wafer seated on the support for translation in mutually perpendicular directions. A stylus support mounted on the bed includes a shaft disposed above and extended across the bed and a truck mounted on the shaft and supported thereby for linear translation along a path extended across the bed a vertically oriented scribe has a diamond tip supported by the truck also adapted as to engage a silicon wafer captured by the chuck and positioned beneath it in order to form score lines in the surface of the wafer as linear translation is imparted to the truck. A chuck positioning means is mounted on the base and is connected to the chuck for positioning the chuck relative to the stylus.

  3. Floating Silicon Method

    SciTech Connect

    Kellerman, Peter

    2013-12-21

    The Floating Silicon Method (FSM) project at Applied Materials (formerly Varian Semiconductor Equipment Associates), has been funded, in part, by the DOE under a “Photovoltaic Supply Chain and Cross Cutting Technologies” grant (number DE-EE0000595) for the past four years. The original intent of the project was to develop the FSM process from concept to a commercially viable tool. This new manufacturing equipment would support the photovoltaic industry in following ways: eliminate kerf losses and the consumable costs associated with wafer sawing, allow optimal photovoltaic efficiency by producing high-quality silicon sheets, reduce the cost of assembling photovoltaic modules by creating large-area silicon cells which are free of micro-cracks, and would be a drop-in replacement in existing high efficiency cell production process thereby allowing rapid fan-out into the industry.

  4. Silicon optical modulators

    NASA Astrophysics Data System (ADS)

    Reed, G. T.; Mashanovich, G.; Gardes, F. Y.; Thomson, D. J.

    2010-08-01

    Optical technology is poised to revolutionize short-reach interconnects. The leading candidate technology is silicon photonics, and the workhorse of such an interconnect is the optical modulator. Modulators have been improved dramatically in recent years, with a notable increase in bandwidth from the megahertz to the multigigahertz regime in just over half a decade. However, the demands of optical interconnects are significant, and many questions remain unanswered as to whether silicon can meet the required performance metrics. Minimizing metrics such as the device footprint and energy requirement per bit, while also maximizing bandwidth and modulation depth, is non-trivial. All of this must be achieved within an acceptable thermal tolerance and optical spectral width using CMOS-compatible fabrication processes. This Review discusses the techniques that have been (and will continue to be) used to implement silicon optical modulators, as well as providing an outlook for these devices and the candidate solutions of the future.

  5. Silicon carbide thyristor

    NASA Technical Reports Server (NTRS)

    Edmond, John A. (Inventor); Palmour, John W. (Inventor)

    1996-01-01

    The SiC thyristor has a substrate, an anode, a drift region, a gate, and a cathode. The substrate, the anode, the drift region, the gate, and the cathode are each preferably formed of silicon carbide. The substrate is formed of silicon carbide having one conductivity type and the anode or the cathode, depending on the embodiment, is formed adjacent the substrate and has the same conductivity type as the substrate. A drift region of silicon carbide is formed adjacent the anode or cathode and has an opposite conductivity type as the anode or cathode. A gate is formed adjacent the drift region or the cathode, also depending on the embodiment, and has an opposite conductivity type as the drift region or the cathode. An anode or cathode, again depending on the embodiment, is formed adjacent the gate or drift region and has an opposite conductivity type than the gate.

  6. Thick silicon growth techniques

    NASA Technical Reports Server (NTRS)

    Bates, H. E.; Mlavsky, A. I.; Jewett, D. N.

    1973-01-01

    Hall mobility measurements on a number of single crystal silicon ribbons grown from graphite dies have shown some ribbons to have mobilities consistent with their resistivities. The behavior of other ribbons appears to be explained by the introduction of impurities of the opposite sign. Growth of a small single crystal silicon ribbon has been achieved from a beryllia dia. Residual internal stresses of the order of 7 to 18,000 psi have been determined to exist in some silicon ribbon, particularly those grown at rates in excess of 1 in./min. Growth experiments have continued toward definition of a configuration and parameters to provide a reasonable yield of single crystal ribbons. High vacuum outgassing of graphite dies and evacuation and backfilling of growth chambers have provided significant improvements in surface quality of ribbons grown from graphite dies.

  7. Cell technology: Advanced silicon sheet

    NASA Technical Reports Server (NTRS)

    Morrison, Andrew D.

    1986-01-01

    The Flat-plate Solar Array (FSA)-sponsored Fourth Silicon Stress/Strain Workshop reviewed, coordinated, and assessed the progress in understanding and controlling stress and strain during the crystal growth of silicon ribbons. dislocation electrical activity and limits on solar cell efficiency, and on studying the effects of dopants on EFG characteristics. Work on silicon for high-efficiency solar cells, stress-strain relationships in silicon ribbon, and high temperature deformation of dendritic web ribbon was also discussed.

  8. Substrate for silicon solar cells

    SciTech Connect

    Thomas, D.E.

    1982-08-10

    A substrate is made for silicon solar cells by heating a sheet of large-grained silicon steel at a temperature of at least about 1300* C. In an atmosphere of hydrogen and tungsten hexafluo (Or hexachloride) at a partial pressure ratio of hydrogen to tungsten hexafluoride of about 3 to about 6 to deposit an epitaxial layer of tungsten on said sheet of silicon steel. Epitaxial silicon can then be deposited in a conventional manner on the layer of epitaxial tungsten.

  9. Micro-miniature gas chromatograph column disposed in silicon wafers

    DOEpatents

    Yu, Conrad M.

    2000-01-01

    A micro-miniature gas chromatograph column is fabricated by forming matching halves of a circular cross-section spiral microcapillary in two silicon wafers and then bonding the two wafers together using visual or physical alignment methods. Heating wires are deposited on the outside surfaces of each wafer in a spiral or serpentine pattern large enough in area to cover the whole microcapillary area inside the joined wafers. The visual alignment method includes etching through an alignment window in one wafer and a precision-matching alignment target in the other wafer. The two wafers are then bonded together using the window and target. The physical alignment methods include etching through vertical alignment holes in both wafers and then using pins or posts through corresponding vertical alignment holes to force precision alignment during bonding. The pins or posts may be withdrawn after curing of the bond. Once the wafers are bonded together, a solid phase of very pure silicone is injected in a solution of very pure chloroform into one end of the microcapillary. The chloroform lowers the viscosity of the silicone enough that a high pressure hypodermic needle with a thumbscrew plunger can force the solution into the whole length of the spiral microcapillary. The chloroform is then evaporated out slowly to leave the silicone behind in a deposit.

  10. Micromachined silicon electrostatic chuck

    SciTech Connect

    Anderson, R.A.; Seager, C.H.

    1994-12-31

    In the field of microelectronics, and in particular the fabrication of microelectronics during plasma etching processes, electrostatic chucks have been used to hold silicon wafers during the plasma etching process. Current electrostatic chucks that operate by the {open_quotes}Johnson-Rahbek Effect{close_quotes} consist of a metallic base plate that is typically coated with a thick layer of slightly conductive dielectric material. A silicon wafer of approximately the same size as the chuck is placed on top of the chuck and a potential difference of several hundred volts is applied between the silicon and the base plate of the electrostatic chuck. This causes an electrostatic attraction proportional to the square of the electric field in the gap between the silicon wafer and the chuck face. When the chuck is used in a plasma filled chamber the electric potential of the wafer tends to be fixed by the effective potential of the plasma. The purpose of the dielectric layer on the chuck is to prevent the silicon wafer from coming into direct electrical contact with the metallic part of the chuck and shorting out the potential difference. On the other hand, a small amount of conductivity appears to be desirable in the dielectric coating so that much of its free surface between points of contact with the silicon wafer is maintained near the potential of the metallic base plate; otherwise, a much larger potential difference would be needed to produce a sufficiently large electric field in the vacuum gap between the wafer and chuck. Typically, the face of the chuck has a pattern of grooves in which about 10 torr pressure of helium gas is maintained. This gas provides cooling (thermal contact) between the wafer and the chuck. A pressure of 10 torr is equivalent to about 0.2 psi.

  11. Light-trapping design for thin-film silicon-perovskite tandem solar cells

    NASA Astrophysics Data System (ADS)

    Foster, Stephen; John, Sajeev

    2016-09-01

    Using finite-difference time-domain simulations, we investigate the optical properties of tandem silicon/perovskite solar cells with a photonic crystal architecture, consisting of a square-lattice array of inverted pyramids with a center-to-center spacing of 2.5 μm. We demonstrate that near-perfect light-trapping and absorption can be achieved over the 300-1100 nm wavelength range with this architecture, using less than 10 μm (equivalent bulk thickness) of crystalline silicon. Using a one-diode model, we obtain projected efficiencies of over 30% for the two-terminal tandem cell under a current-matching condition, well beyond the current record for single-junction silicon solar cells. The architecture is amenable to mass fabrication through wet-etching and uses a fraction of the silicon of traditional designs, making it an attractive alternative to other silicon-perovskite tandem designs.

  12. Dual exposure, two-photon, conformal phasemask lithography for three dimensional silicon inverse woodpile photonic crystals

    SciTech Connect

    Shir, Daniel J.; Nelson, Erik C.; Chanda, Debashis; Brzezinski, Andrew; Braun, Paul V.; Rogers, John A.; Wiltzius, Pierre

    2010-01-01

    The authors describe the fabrication and characterization of three dimensional silicon inverse woodpile photonic crystals. A dual exposure, two-photon, conformal phasemask technique is used to create high quality polymer woodpile structures over large areas with geometries that quantitatively match expectations based on optical simulations. Depositing silicon into these templates followed by the removal of the polymer results in silicon inverse woodpile photonic crystals for which calculations indicate a wide, complete photonic bandgap over a range of structural fill fractions. Spectroscopic measurements of normal incidence reflection from both the polymer and siliconphotonic crystals reveal good optical properties.

  13. Large area sheet task. Advanced dendritic web growth development. [silicon films

    NASA Technical Reports Server (NTRS)

    Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Hopkins, R. H.; Meier, D.; Frantti, E.; Schruben, J.

    1981-01-01

    The development of a silicon dendritic web growth machine is discussed. Several refinements to the sensing and control equipment for melt replenishment during web growth are described and several areas for cost reduction in the components of the prototype automated web growth furnace are identified. A circuit designed to eliminate the sensitivity of the detector signal to the intensity of the reflected laser beam used to measure melt level is also described. A variable speed motor for the silicon feeder is discussed which allows pellet feeding to be accomplished at a rate programmed to match exactly the silicon removed by web growth.

  14. Electrochemical thinning of silicon

    DOEpatents

    Medernach, J.W.

    1994-01-11

    Porous semiconducting material, e.g. silicon, is formed by electrochemical treatment of a specimen in hydrofluoric acid, using the specimen as anode. Before the treatment, the specimen can be masked. The porous material is then etched with a caustic solution or is oxidized, depending of the kind of structure desired, e.g. a thinned specimen, a specimen, a patterned thinned specimen, a specimen with insulated electrical conduits, and so on. Thinned silicon specimen can be subjected to tests, such as measurement of interstitial oxygen by Fourier transform infra-red spectroscopy (FTIR). 14 figures.

  15. Electrochemical thinning of silicon

    DOEpatents

    Medernach, John W.

    1994-01-01

    Porous semiconducting material, e.g. silicon, is formed by electrochemical treatment of a specimen in hydrofluoric acid, using the specimen as anode. Before the treatment, the specimen can be masked. The porous material is then etched with a caustic solution or is oxidized, depending of the kind of structure desired, e.g. a thinned specimen, a specimen, a patterned thinned specimen, a specimen with insulated electrical conduits, and so on. Thinned silicon specimen can be subjected to tests, such as measurement of interstitial oxygen by Fourier transform infra-red spectroscopy (FTIR).

  16. Silicon sheet technologies

    SciTech Connect

    Ciszek, T.F.

    1982-09-01

    A classification of silicon sheet growth methods by meniscus geometry permits them to be discussed in three groups: short meniscus techniques, high meniscus techniques, and extended meniscus or large solid/liquid interface area techniques. A second parameter, meniscus shaper interaction with the liquid silicon, is also instrumental in determining the characteristics of the various sheet processes. The current status of each process is discussed in the context of meniscus geometry and shaper/melt interaction. One aspect of sheet growth, surface area generation rate, is quantitatively compared with combined ingot growth and wafering surface area generation rates.

  17. Fracture toughness of silicon

    NASA Technical Reports Server (NTRS)

    Chen, C. P.; Leipold, M. H.

    1980-01-01

    The paper presents a study to determine the fracture toughness and to characterize fracture modes of silicon as a function of the orientation of single-crystal and polycrystalline material. It is shown that bar specimens cracked by Knoop microhardness indentation and tested to fracture under four-point bending at room temperature were used to determine the fracture toughness values. It is found that the lowest fracture toughness value of single crystal silicon was 0.82 MN/m to the 3/2 in the 111 plane type orientation, although the difference in values in the 111, 110, and 100 planes was small.

  18. Syntactic Pattern Recognition Approach To Scene Matching

    NASA Astrophysics Data System (ADS)

    Gilmore, John F.

    1983-03-01

    This paper describes a technique for matching two images containing natural terrain and tactical objects using syntactic pattern recognition. A preprocessor analyzes each image to identify potential areas of interest. Points of interest in an image are classified and a graph possessing properties of invariance is created based on these points. Classification derived grammar strings are generated for each classified graph structure. A local match analysis is performed and the best global match is constructed. A probability-of-match metric is computed in order to evaluate the global match. Examples demonstrating these steps are provided and actual FLIR image results are shown.

  19. Matching network for RF plasma source

    DOEpatents

    Pickard, Daniel S.; Leung, Ka-Ngo

    2007-11-20

    A compact matching network couples an RF power supply to an RF antenna in a plasma generator. The simple and compact impedance matching network matches the plasma load to the impedance of a coaxial transmission line and the output impedance of an RF amplifier at radio frequencies. The matching network is formed of a resonantly tuned circuit formed of a variable capacitor and an inductor in a series resonance configuration, and a ferrite core transformer coupled to the resonantly tuned circuit. This matching network is compact enough to fit in existing compact focused ion beam systems.

  20. Light emission from porous silicon

    NASA Astrophysics Data System (ADS)

    Penczek, John

    The continuous evolution of silicon microelectronics has produced significant gains in electronic information processing. However, greater improvements in performance are expected by utilizing optoelectronic techniques. But these techniques have been severely limited in silicon- based optoelectronics due to the lack of an efficient silicon light emitter. The recent observation of efficient light emission from porous silicon offer a promising opportunity to develop a suitable silicon light source that is compatible with silicon microelectronics. This dissertation examined the porous silicon emission mechanism via photoluminescence, and by a novel device structure for porous silicon emitters. The investigation first examined the correlation between porous silicon formation conditions (and subsequent morphology) with the resulting photoluminescence properties. The quantum confinement theory for porous silicon light emission contends that the morphology changes induced by the different formation conditions determine the optical properties of porous silicon. The photoluminescence spectral shifts measured in this study, in conjunction with TEM analysis and published morphological data, lend support to this theory. However, the photoluminescence spectral broadening was attributed to electronic wavefunction coupling between adjacent silicon nanocrystals. An novel device structure was also investigated in an effort to improve current injection into the porous silicon layer. The selective etching properties of porous silicon were used to create a p-i-n structure with crystalline silicon contacts to the porous silicon layer. The resulting device was found to have unique characteristics, with a negative differential resistance region and current-induced emission that spanned from 400 nm to 5500 nm. The negative differential resistance was correlated to resistive heating effects in the device. A numerical analysis of thermal emission spectra from silicon films, in addition to

  1. Semi-Global Matching in Object Space

    NASA Astrophysics Data System (ADS)

    Bethmann, F.; Luhmann, T.

    2015-03-01

    Semi-Global Matching (SGM) is a widespread algorithm for image matching which is used for very different applications, ranging from real-time applications (e.g. for generating 3D data for driver assistance systems) to aerial image matching. Originally developed for stereo-image matching, several extensions have been proposed to use more than two images within the matching process (multi-baseline matching, multi-view stereo). These extensions still perform the image matching in (rectified) stereo images and combine the pairwise results afterwards to create the final solution. This paper proposes an alternative approach which is suitable for the introduction of an arbitrary number of images into the matching process and utilizes image matching by using non-rectified images. The new method differs from the original SGM method mainly in two aspects: Firstly, the cost calculation is formulated in object space within a dense voxel raster by using the grey (or colour) values of all images instead of pairwise cost calculation in image space. Secondly, the semi-global (path-wise) minimization process is transferred into object space as well, so that the result of semi-global optimization leads to index maps (instead of disparity maps) which directly indicate the 3D positions of the best matches. Altogether, this yields to an essential simplification of the matching process compared to multi-view stereo (MVS) approaches. After a description of the new method, results achieved from two different datasets (close-range and aerial) are presented and discussed.

  2. A probabilistic approach to spectral graph matching.

    PubMed

    Egozi, Amir; Keller, Yosi; Guterman, Hugo

    2013-01-01

    Spectral Matching (SM) is a computationally efficient approach to approximate the solution of pairwise matching problems that are np-hard. In this paper, we present a probabilistic interpretation of spectral matching schemes and derive a novel Probabilistic Matching (PM) scheme that is shown to outperform previous approaches. We show that spectral matching can be interpreted as a Maximum Likelihood (ML) estimate of the assignment probabilities and that the Graduated Assignment (GA) algorithm can be cast as a Maximum a Posteriori (MAP) estimator. Based on this analysis, we derive a ranking scheme for spectral matchings based on their reliability, and propose a novel iterative probabilistic matching algorithm that relaxes some of the implicit assumptions used in prior works. We experimentally show our approaches to outperform previous schemes when applied to exhaustive synthetic tests as well as the analysis of real image sequences.

  3. Silicon carbide reinforced silicon carbide composite

    NASA Technical Reports Server (NTRS)

    Lau, Sai-Kwing (Inventor); Calandra, Salvatore J. (Inventor); Ohnsorg, Roger W. (Inventor)

    2001-01-01

    This invention relates to a process comprising the steps of: a) providing a fiber preform comprising a non-oxide ceramic fiber with at least one coating, the coating comprising a coating element selected from the group consisting of carbon, nitrogen, aluminum and titanium, and the fiber having a degradation temperature of between 1400.degree. C. and 1450.degree. C., b) impregnating the preform with a slurry comprising silicon carbide particles and between 0.1 wt % and 3 wt % added carbon c) providing a cover mix comprising: i) an alloy comprising a metallic infiltrant and the coating element, and ii) a resin, d) placing the cover mix on at least a portion of the surface of the porous silicon carbide body, e) heating the cover mix to a temperature between 1410.degree. C. and 1450.degree. C. to melt the alloy, and f) infiltrating the fiber preform with the melted alloy for a time period of between 15 minutes and 240 minutes, to produce a ceramic fiber reinforced ceramic composite.

  4. Pair distribution functions of silicon/silicon nitride interfaces

    NASA Astrophysics Data System (ADS)

    Cao, Deng; Bachlechner, Martina E.

    2006-03-01

    Using molecular dynamics simulations, we investigate different mechanical and structural properties of the silicon/silicon nitride interface. One way to characterize the structure as tensile strain is applied parallel to the interface is to calculate pair distribution functions for specific atom types. The pair distribution function gives the probability of finding a pair of atoms a distance r apart, relative to the probability expected for a completely random distribution at the same density. The pair distribution functions for bulk silicon nitride reflect the fracture of the silicon nitride film at about 8 % and the fact that the centerpiece of the silicon nitride film returns to its original structure after fracture. The pair distribution functions for interface silicon atoms reveal the formation of bonds for originally unbound atom pairs, which is indicative of the interstitial-vacancy defect that causes failure in silicon.

  5. Best Practices for NPT Transit Matching

    SciTech Connect

    Gilligan, Kimberly V.; Whitaker, J. Michael; Oakberg, John A.; Snow, Catherine

    2016-09-01

    Transit matching is the process for relating or matching reports of shipments and receipts submitted to the International Atomic Energy Agency (IAEA). Transit matching is a component used by the IAEA in drawing safeguards conclusions and performing investigative analysis. Transit matching is part of IAEA safeguards activities and the State evaluation process, and it is included in the annual Safeguards Implementation Report (SIR). Annually, the IAEA currently receives reports of ~900,000 nuclear material transactions, of which ~500,000 are for domestic and foreign transfers. Of these the IAEA software can automatically match (i.e., machine match) about 95% of the domestic transfers and 25% of the foreign transfers. Given the increasing demands upon IAEA resources, it is highly desirable for the machine-matching process to match as many transfers as possible. Researchers at Oak Ridge National Laboratory (ORNL) have conducted an investigation funded by the National Nuclear Security Administration through the Next Generation Safeguards Initiative to identify opportunities to strengthen IAEA transit matching. Successful matching, and more specifically machine matching, is contingent on quality data from the reporting States. In February 2016, ORNL hosted representatives from three States, the IAEA, and Euratom to share results from past studies and to discuss the processes, policies, and procedures associated with State reporting for transit matching. Drawing on each entity's experience and knowledge, ORNL developed a best practices document to be shared with the international safeguards community to strengthen transit matching. This paper shares the recommendations that resulted from this strategic meeting and the next steps being taken to strengthen transit matching.

  6. Vorticity matching in superfluid helium

    NASA Astrophysics Data System (ADS)

    Samuels, David C.

    1991-12-01

    Recent experiments have rekindled interest in high Reynolds number flows using superfluid helium. In a continuing series of experiments, the flow of helium II through various devices (smooth pipes, corrugated pipes, valves, venturies, turbine flowmeters, and coanda flowmeters for example) was investigated. In all cases, the measured values (typically, mass flow rates and pressure drops) were found to be well described by classical relations for high Reynolds flows. This is unexpected since helium II consists of two interpenetrating fluids; one fluid with nonzero viscosity (the normal fluid) and one with zero viscosity (the superfluid). Only the normal fluid component should directly obey classical relations. Since the experiments listed above only measure the external behavior of the flow (i.e., pressure drops over devices), there is a great deal of room for interpretation of their results. One possible interpretation is that in turbulent flows the normal fluid and the superfluid velocity fields are somehow 'locked' together, presumably by the mutual friction force between the superfluid vortex filaments and the normal fluid. We refer to this locking together of the two fluids as 'vorticity matching.'

  7. Impedance matching at arterial bifurcations.

    PubMed

    Brown, N

    1993-01-01

    Reflections of pulse waves will occur in arterial bifurcations unless the impedance is matched continuously through changing geometric and elastic properties. A theoretical model is presented which minimizes pulse wave reflection through bifurcations. The model accounts for the observed linear changes in area within the bifurcation, generalizes the theory to asymmetrical bifurcations, characterizes changes in elastic properties from parent to daughter arteries, and assesses the effect of branch angle on the mechanical properties of daughter vessels. In contradistinction to previous models, reflections cannot be minimized without changes in elastic properties through bifurcations. The theoretical model predicts that in bifurcations with area ratios (beta) less than 1.0 Young's moduli of daughter vessels may be less than that in the parent vessel if the Womersley parameter alpha in the parent vessel is less than 5. Larger area ratios in bifurcations are accompanied by greater increases in Young's moduli of branches. For an idealized symmetric aortic bifurcation (alpha = 10) with branching angles theta = 30 degrees (opening angle 60 degrees) Young's modulus of common iliac arteries relative to that of the distal abdominal aorta has an increase of 1.05, 1.68 and 2.25 for area ratio of 0.8, 1.0 and 1.15, respectively. These predictions are consistent with the observed increases in Young's moduli of peripheral vessels.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Distributed Search and Pattern Matching

    NASA Astrophysics Data System (ADS)

    Ahmed, Reaz; Boutaba, Raouf

    Peer-to-peer (P2P) technology has triggered a wide range of distributed applications including file-sharing, distributed XML databases, distributed computing, server-less web publishing and networked resource/service sharing. Despite of the diversity in application, these systems share common requirements for searching due to transitory nodes population and content volatility. In such dynamic environment, users do not have the exact information about available resources. Queries are based on partial information. This mandates the search mechanism to be emphflexible. On the other hand, the search mechanism is required to be bandwidth emphefficient to support large networks. Variety of search techniques have been proposed to provide satisfactory solution to the conflicting requirements of search efficiency and flexibility. This chapter highlights the search requirements in large scale distributed systems and the ability of the existing distributed search techniques in satisfying these requirements. Representative search techniques from three application domains, namely, P2P content sharing, service discovery and distributed XML databases, are considered. An abstract problem formulation called Distributed Pattern Matching (DPM) is presented as well. The DPM framework can be used as a common ground for addressing the search problem in these three application domains.

  9. Matching roots to their environment

    PubMed Central

    White, Philip J.; George, Timothy S.; Gregory, Peter J.; Bengough, A. Glyn; Hallett, Paul D.; McKenzie, Blair M.

    2013-01-01

    Background Plants form the base of the terrestrial food chain and provide medicines, fuel, fibre and industrial materials to humans. Vascular land plants rely on their roots to acquire the water and mineral elements necessary for their survival in nature or their yield and nutritional quality in agriculture. Major biogeochemical fluxes of all elements occur through plant roots, and the roots of agricultural crops have a significant role to play in soil sustainability, carbon sequestration, reducing emissions of greenhouse gasses, and in preventing the eutrophication of water bodies associated with the application of mineral fertilizers. Scope This article provides the context for a Special Issue of Annals of Botany on ‘Matching Roots to Their Environment’. It first examines how land plants and their roots evolved, describes how the ecology of roots and their rhizospheres contributes to the acquisition of soil resources, and discusses the influence of plant roots on biogeochemical cycles. It then describes the role of roots in overcoming the constraints to crop production imposed by hostile or infertile soils, illustrates root phenotypes that improve the acquisition of mineral elements and water, and discusses high-throughput methods to screen for these traits in the laboratory, glasshouse and field. Finally, it considers whether knowledge of adaptations improving the acquisition of resources in natural environments can be used to develop root systems for sustainable agriculture in the future. PMID:23821619

  10. Selective formation of porous silicon

    NASA Technical Reports Server (NTRS)

    Fathauer, Robert W. (Inventor); Jones, Eric W. (Inventor)

    1993-01-01

    A pattern of porous silicon is produced in the surface of a silicon substrate by forming a pattern of crystal defects in said surface, preferably by applying an ion milling beam through openings in a photoresist layer to the surface, and then exposing said surface to a stain etchant, such as HF:HNO3:H2O. The defected crystal will preferentially etch to form a pattern of porous silicon. When the amorphous content of the porous silicon exceeds 70 percent, the porous silicon pattern emits visible light at room temperature.

  11. Selective formation of porous silicon

    NASA Technical Reports Server (NTRS)

    Fathauer, Jones (Inventor)

    1993-01-01

    A pattern of porous silicon is produced in the surface of a silicon substrate by forming a pattern of crystal defects in said surface, preferably by applying an ion milling beam through openings in a photoresist layer to the surface, and then exposing said surface to a stain etchant, such as HF:HNO3:H20. The defected crystal will preferentially etch to form a pattern of porous silicon. When the amorphous content of the porous silicon exceeds 70 percent, the porous silicon pattern emits visible light at room temperature.

  12. In-design process hotspot repair using pattern matching

    NASA Astrophysics Data System (ADS)

    Jang, Daehyun; Ha, Naya; Jeon, Junsu; Kang, Jae-Hyun; Paek, Seung Weon; Choi, Hungbok; Kim, Kee Sup; Lai, Ya-Chieh; Hurat, Philippe; Luo, Wilbur

    2012-03-01

    As patterning for advanced processes becomes more challenging, designs must become more process-aware. The conventional approach of running lithography simulation on designs to detect process hotspots is prohibitive in terms of runtime for designers, and also requires the release of highly confidential process information. Therefore, a more practical approach is required to make the In-Design process-aware methodology more affordable in terms of maintenance, confidentiality, and runtime. In this study, a pattern-based approach is chosen for Process Hotspot Repair (PHR) because it accurately captures the manufacturability challenges without releasing sensitive process information. Moreover, the pattern-based approach is fast and well integrated in the design flow. Further, this type of approach is very easy to maintain and extend. Once a new process weak pattern has been discovered (caused by Chemical Mechanical Polishing (CMP), etch, lithography, and other process steps), the pattern library can be quickly and easily updated and released to check and fix subsequent designs. This paper presents the pattern matching flow and discusses its advantages. It explains how a pattern library is created from the process weak patterns found on silicon wafers. The paper also discusses the PHR flow that fixes process hotspots in a design, specifically through the use of pattern matching and routing repair.

  13. Solar generator performance with load matching to water electrolysis

    NASA Astrophysics Data System (ADS)

    Freudenberg, K.

    1982-08-01

    A 7 W generator, based on monocrystalline silicon solar cells, was directly wired to an electronic load, simulating the current-voltage characteristic of an advanced water electrolyzer. System performance was monitored from January 15 to July 7, 1980. Measurements included current and voltage at the load and at the point of maximum power output, global irradiance and ambient temperature. Solar generator efficiency ranged from 7.5% to 11.5%. A large spread of + or - 1% in instantaneous generator efficiency was observed at identical values of global irradiance and ambient temperature. The dependence of the average generator efficiency on global irradiance and ambient temperature is given by a simple relation to an accuracy of + or - 0.2%. Load matching was optimized for high global irradiance at high ambient temperature. Averaged over the half year, period losses by nonideal load matching amounted to only 8.9%. Assuming an ideal current efficiency of the simulated water electrolyzer, the overall efficiency of hydrogen production was 8.0%.

  14. Silicon Carbide Metallization

    NASA Astrophysics Data System (ADS)

    Lescoat, F.; Tanguy, F.; Durand, P.

    2016-05-01

    A study has been done to assess the feasibility of metallization of Silicon Carbide (SiC) in order to simplify design and mounting of one or more ground reference rail needed to provide an electrical reference for electronics mounted on an SiC structure.

  15. Silicon Raman polarizer.

    PubMed

    Kozlov, Victor V; Wabnitz, Stefan

    2012-02-15

    We theoretically investigate the polarization properties of Raman amplifiers based on silicon-on-insulator waveguides, and show that it is possible to realize a waveguide Raman polarizer. The Raman polarizer is a special type of Raman amplifier with the property of producing an amplified and highly repolarized beam when it is fed by a relatively weak and unpolarized signal.

  16. Composition Comprising Silicon Carbide

    NASA Technical Reports Server (NTRS)

    Mehregany, Mehran (Inventor); Zorman, Christian A. (Inventor); Fu, Xiao-An (Inventor); Dunning, Jeremy L. (Inventor)

    2012-01-01

    A method of depositing a ceramic film, particularly a silicon carbide film, on a substrate is disclosed in which the residual stress, residual stress gradient, and resistivity are controlled. Also disclosed are substrates having a deposited film with these controlled properties and devices, particularly MEMS and NEMS devices, having substrates with films having these properties.

  17. Silicone/Acrylate Copolymers

    NASA Technical Reports Server (NTRS)

    Dennis, W. E.

    1982-01-01

    Two-step process forms silicone/acrylate copolymers. Resulting acrylate functional fluid is reacted with other ingredients to produce copolymer. Films of polymer were formed by simply pouring or spraying mixture and allowing solvent to evaporate. Films showed good weatherability. Durable, clear polymer films protect photovoltaic cells.

  18. Characterization of Silicon Carbide.

    DTIC Science & Technology

    The various electrical and structural measurement techniques for silicon carbide are described. The electrical measurements include conductivity, resistivity, carrier concentration, mobility, doping energy levels, and lifetime. The structural measurements include polytype determination and crystalline perfection. Both bulk and epitaxial films are included.

  19. Analysis of porous silicon

    NASA Astrophysics Data System (ADS)

    Earwaker, L. G.; Farr, J. P. G.; Grzeszczyk, P. E.; Sturland, I.; Keen, J. M.

    1985-06-01

    Porous silicon, suitable after oxidation for dielectric isolation, has been produced successfully by anodizing silicon in strong HF. The oxidized layer has been shown to have promise in device manufacture, providing high packing densities and radiation hardness. Anodizing has been carried out using both single and double cells, following the effects of current density. HF concentration and silicon resistivity. The resultant porous layers have been characterised with respect to composition and structure. The materials produced differ considerably in lattice strain, composition and reactivities. Prompt radiation analyses 19F(p,αγ), 16O(d,α), 12C(d,p), are useful for monitoring the anodizing procedures and subsequent oxidation: currently, interest centres on the mechanistic information obtained. RBS analysis using α-particles gives a much lower Si response from porous than from bulk silicon. Glancing angle proton recoil analyses reveal considerable quantities of hydrogen in the porous layers. These mutually consistent findings have considerable mechanistic significance; extensive Si-H bonding occurs following a 2 equivalent Faradaic process.

  20. Amorphous silicon photovoltaic devices

    DOEpatents

    Carlson, David E.; Lin, Guang H.; Ganguly, Gautam

    2004-08-31

    This invention is a photovoltaic device comprising an intrinsic or i-layer of amorphous silicon and where the photovoltaic device is more efficient at converting light energy to electric energy at high operating temperatures than at low operating temperatures. The photovoltaic devices of this invention are suitable for use in high temperature operating environments.

  1. Microgravity Silicon Zoning Investigation

    NASA Technical Reports Server (NTRS)

    Kern, E. L.

    1985-01-01

    This research program is directed toward the understanding of the float zone crystal growth process, the melt interactions which lead to crystal inhomogeneities, and the influence of microgravity on reducing these inhomogeneities. Silicon was selected as the model crystal because its inhomogeneities lead to known variations in device performance, and because the mechanisms involved in its growth are understood better than for other high temperature crystals. The objective of the program is to understand the growth mechanisms in float zone growth and thereby determine the feasibility and advantages of float zone growth of silicon under microgravity conditions. This will be done by characterizing the growth at g = 1, projecting the changes in melt flows due to microgravity, observing these in space growth and determining the effects on defective inhomogeneities. A Thin Rod Zoner was constructed as a laboratory prototype for flight growth of 5 mm diameter silicon crystals, which can be done within the power and cooling capabilities of shuttle flights. A new method of zoning silicon, using resistance heating, has resulted in melting 5 mm diameter ingots.

  2. Crystallization of silicon films on glass: a comparison of methods

    SciTech Connect

    Lemons, R.A.; Bosch, M.A.; Herbst, D.

    1983-01-01

    The lure of flat panel displays has stimulated much research on the crystallization of silicon films deposited on large-area transparent substrates. In most respects, fused quartz is ideal. It has high purity, thermal shock resistance, and a softening point above the silicon melting temperature. Unfortunately, fused quartz has such a small thermal expansion that the silicon film cracks as it cools. This problem has been attacked by patterning with islands or moats before and after crystallization, by capping, and by using silicate glass substrates that match the thermal expansion of silicon. The relative merits of these methods are compared. Melting of the silicon film to achieve high mobility has been accomplished by a variety of methods including lasers, electron beams, and strip heaters. For low melting temperature glasses, surface heating with a laser or electron beam is essential. Larger grains are obtained with the high bias temperature, strip heater techniques. The low-angle grain boundaries characteristic of these films may be caused by constitutional undercooling. A model is developed to predict the boundary spacing as a function of scan rate and temperature gradient.

  3. Match-bounded String Rewriting Systems

    NASA Technical Reports Server (NTRS)

    Geser, Alfons; Hofbauer, Dieter; Waldmann, Johannes

    2003-01-01

    We introduce a new class of automated proof methods for the termination of rewriting systems on strings. The basis of all these methods is to show that rewriting preserves regular languages. To this end, letters are annotated with natural numbers, called match heights. If the minimal height of all positions in a redex is h+1 then every position in the reduct will get height h+1. In a match-bounded system, match heights are globally bounded. Using recent results on deleting systems, we prove that rewriting by a match-bounded system preserves regular languages. Hence it is decidable whether a given rewriting system has a given match bound. We also provide a sufficient criterion for the abence of a match-bound. The problem of existence of a match-bound is still open. Match-boundedness for all strings can be used as an automated criterion for termination, for match-bounded systems are terminating. This criterion can be strengthened by requiring match-boundedness only for a restricted set of strings, for instance the set of right hand sides of forward closures.

  4. Silicon oxidation in fluoride solutions

    NASA Technical Reports Server (NTRS)

    Sancier, K. M.; Kapur, V.

    1980-01-01

    Silicon is produced in a NaF, Na2SiF6, and Na matrix when SiF4 is reduced by metallic sodium. Hydrogen is evolved during acid leaching to separate the silicon from the accompanying reaction products, NaF and Na2SiF6. The hydrogen evolution reaction was studied under conditions simulating leaching conditions by making suspensions of the dry silicon powder in aqueous fluoride solutions. The mechanism for the hydrogen evolution is discussed in terms of spontaneous oxidation of silicon resulting from the cooperative effects of (1) elemental sodium in the silicon that reacts with water to remove a protective silica layer, leaving clean reactive silicon, and (2) fluoride in solution that complexes with the oxidized silicon in solution and retards formation of a protective hydrous oxide gel.

  5. Improved toughness of silicon carbide

    NASA Technical Reports Server (NTRS)

    Palm, J. A.

    1975-01-01

    Several techniques were employed to apply or otherwise form porous layers of various materials on the surface of hot-pressed silicon carbide ceramic. From mechanical properties measurements and studies, it was concluded that although porous layers could be applied to the silicon carbide ceramic, sufficient damage was done to the silicon carbide surface by the processing required so as to drastically reduce its mechanical strength. It was further concluded that there was little promise of success in forming an effective energy absorbing layer on the surface of already densified silicon carbide ceramic that would have the mechanical strength of the untreated or unsurfaced material. Using a process for the pressureless sintering of silicon carbide powders it was discovered that porous layers of silicon carbide could be formed on a dense, strong silicon carbide substrate in a single consolidation process.

  6. Impact of plant growth promoting Pseudomonas monteilii PsF84 and Pseudomonas plecoglossicida PsF610 on metal uptake and production of secondary metabolite (monoterpenes) by rose-scented geranium (Pelargonium graveolens cv. bourbon) grown on tannery sludge amended soil.

    PubMed

    Dharni, Seema; Srivastava, Atul Kumar; Samad, Abdul; Patra, Dharani Dhar

    2014-12-01

    Bacterial strains PsF84 and PsF610 were isolated from tannery sludge polluted soil, Jajmau, Kanpur, India. 16S rRNA gene sequence and phylogenetic analysis confirmed the taxonomic affiliation of PsF84 as Pseudomonas monteilii and PsF610 as Pseudomonas plecoglossicida. A greenhouse study was carried out with rose-scented geranium (Pelargonium graveolenscv. bourbon) grown in soil treated with tannery sludge in different proportions viz. soil: sludge ratio of 100:0, 25:75, 50:50, 75:25 and 0:100 to evaluate the effects of bacterial inoculation on the heavy metal uptake. The isolates solubilized inorganic phosphorus and were capable of producing indole acetic acid (IAA) and siderophore. The isolate PsF84 increased the dry biomass of shoot by 44%, root by 48%, essential oil yield 43% and chlorophyll by 31% respectively over uninoculated control. The corresponding increase with the isolate PsF610 were 38%, 40%, 39% and 28%, respectively. Scanning electron microscopic (SEM) studies reveal that the Cr(VI) accumulation resulted in breakdown of vascular bundles and sequesters Cr(VI) in roots. The glandular trichomes (GT) were investigated using SEM studies as these glands are probably the main site of essential oil synthesis. Owing to its wide action spectrum, these isolates could serve as an effective metal sequestering and bioinoculants due to the production of IAA, siderophore and solubilization of phosphate for geranium in metal-stressed soil. The present study has provided a new insight into the phytoremediation of metal-contaminated soil.

  7. Coincident site lattice-matched growth of semiconductors on substrates using compliant buffer layers

    DOEpatents

    Norman, Andrew

    2016-08-23

    A method of producing semiconductor materials and devices that incorporate the semiconductor materials are provided. In particular, a method is provided of producing a semiconductor material, such as a III-V semiconductor, on a silicon substrate using a compliant buffer layer, and devices such as photovoltaic cells that incorporate the semiconductor materials. The compliant buffer material and semiconductor materials may be deposited using coincident site lattice-matching epitaxy, resulting in a close degree of lattice matching between the substrate material and deposited material for a wide variety of material compositions. The coincident site lattice matching epitaxial process, as well as the use of a ductile buffer material, reduce the internal stresses and associated crystal defects within the deposited semiconductor materials fabricated using the disclosed method. As a result, the semiconductor devices provided herein possess enhanced performance characteristics due to a relatively low density of crystal defects.

  8. Multifunctional epitaxial systems on silicon substrates

    NASA Astrophysics Data System (ADS)

    Singamaneni, Srinivasa Rao; Prater, John Thomas; Narayan, Jagdish

    2016-09-01

    Multifunctional heterostructures can exhibit a wide range of functional properties, including colossal magneto-resistance, magnetocaloric, and multiferroic behavior, and can display interesting physical phenomena including spin and charge ordering and strong spin-orbit coupling. However, putting this functionality to work remains a challenge. To date, most of the work reported in the literature has dealt with heterostructures deposited onto closely lattice matched insulating substrates such as DyScO3, SrTiO3 (STO), or STO buffered Si(100) using concepts of lattice matching epitaxy (LME). However, strain in heterostructures grown by LME is typically not fully relaxed and the layers contain detrimental defects such as threading dislocations that can significantly degrade the physical properties of the films and adversely affect the device characteristics. In addition, most of the substrates are incompatible with existing CMOS-based technology, where Si (100) substrates dominate. This review discusses recent advances in the integration of multifunctional oxide and non-oxide materials onto silicon substrates. An alternative thin film growth approach, called "domain matching epitaxy," is presented which identifies approaches for minimizing lattice strain and unwanted defects in large misfit systems (7%-25% and higher). This approach broadly allows for the integration of multifunctional materials onto silicon substrates, such that sensing, computation, and response functions can be combined to produce next generation "smart" devices. In general, pulsed laser deposition has been used to epitaxially grow these materials, although the concepts developed here can be extended to other deposition techniques, as well. It will be shown that TiN and yttria-stabilized zirconia template layers provide promising platforms for the integration of new functionality into silicon-based computer chips. This review paper reports on a number of thin-film heterostructure systems that span a

  9. Current and lattice matched tandem solar cell

    DOEpatents

    Olson, Jerry M.

    1987-01-01

    A multijunction (cascade) tandem photovoltaic solar cell device is fabricated of a Ga.sub.x In.sub.1-x P (0.505.ltoreq.X.ltoreq.0.515) top cell semiconductor lattice matched to a GaAs bottom cell semiconductor at a low-resistance heterojunction, preferably a p+/n+ heterojunction between the cells. The top and bottom cells are both lattice matched and current matched for high efficiency solar radiation conversion to electrical energy.

  10. Improving the Nephrology Match: the Path Forward.

    PubMed

    Hsu, Chi-yuan; Parker, Mark G; Ross, Michael J; Schmidt, Rebecca J; Harris, Raymond C

    2015-11-01

    The Fellowship Match process was designed to provide applicants and program directors with an opportunity to consider all their options before making decisions about post-residency training. In a Match, applicants can choose the programs that best suit their career goals, and program directors can consider all candidates before preparing a rank order list. The Match is a contract, requiring obligations of both programs and applicants to achieve success, ensure uniformity, and standardize participation.

  11. Anomalous dispersion enhanced Cerenkov phase-matching

    SciTech Connect

    Kowalczyk, T.C.; Singer, K.D.; Cahill, P.A.

    1993-11-01

    The authors report on a scheme for phase-matching second harmonic generation in polymer waveguides based on the use of anomalous dispersion to optimize Cerenkov phase matching. They have used the theoretical results of Hashizume et al. and Onda and Ito to design an optimum structure for phase-matched conversion. They have found that the use of anomalous dispersion in the design results in a 100-fold enhancement in the calculated conversion efficiency. This technique also overcomes the limitation of anomalous dispersion phase-matching which results from absorption at the second harmonic. Experiments are in progress to demonstrate these results.

  12. 44 CFR 361.4 - Matching contributions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... HOMELAND SECURITY PREPAREDNESS NATIONAL EARTHQUAKE HAZARDS REDUCTION ASSISTANCE TO STATE AND LOCAL GOVERNMENTS Earthquake Hazards Reduction Assistance Program § 361.4 Matching contributions. (a) All...

  13. 44 CFR 361.4 - Matching contributions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... HOMELAND SECURITY PREPAREDNESS NATIONAL EARTHQUAKE HAZARDS REDUCTION ASSISTANCE TO STATE AND LOCAL GOVERNMENTS Earthquake Hazards Reduction Assistance Program § 361.4 Matching contributions. (a) All...

  14. 44 CFR 361.4 - Matching contributions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... HOMELAND SECURITY PREPAREDNESS NATIONAL EARTHQUAKE HAZARDS REDUCTION ASSISTANCE TO STATE AND LOCAL GOVERNMENTS Earthquake Hazards Reduction Assistance Program § 361.4 Matching contributions. (a) All...

  15. 44 CFR 361.4 - Matching contributions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... HOMELAND SECURITY PREPAREDNESS NATIONAL EARTHQUAKE HAZARDS REDUCTION ASSISTANCE TO STATE AND LOCAL GOVERNMENTS Earthquake Hazards Reduction Assistance Program § 361.4 Matching contributions. (a) All...

  16. 44 CFR 361.4 - Matching contributions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... HOMELAND SECURITY PREPAREDNESS NATIONAL EARTHQUAKE HAZARDS REDUCTION ASSISTANCE TO STATE AND LOCAL GOVERNMENTS Earthquake Hazards Reduction Assistance Program § 361.4 Matching contributions. (a) All...

  17. PUMA: The Positional Update and Matching Algorithm

    NASA Astrophysics Data System (ADS)

    Line, J. L. B.; Webster, R. L.; Pindor, B.; Mitchell, D. A.; Trott, C. M.

    2017-01-01

    We present new software to cross-match low-frequency radio catalogues: the Positional Update and Matching Algorithm. The Positional Update and Matching Algorithm combines a positional Bayesian probabilistic approach with spectral matching criteria, allowing for confusing sources in the matching process. We go on to create a radio sky model using Positional Update and Matching Algorithm based on the Murchison Widefield Array Commissioning Survey, and are able to automatically cross-match 98.5% of sources. Using the characteristics of this sky model, we create simple simulated mock catalogues on which to test the Positional Update and Matching Algorithm, and find that Positional Update and Matching Algorithm can reliably find the correct spectral indices of sources, along with being able to recover ionospheric offsets. Finally, we use this sky model to calibrate and remove foreground sources from simulated interferometric data, generated using OSKAR (the Oxford University visibility generator). We demonstrate that there is a substantial improvement in foreground source removal when using higher frequency and higher resolution source positions, even when correcting positions by an average of 0.3 arcmin given a synthesised beam-width of 2.3 arcmin.

  18. Develop Silicone Encapsulation Systems for Terrestrial Silicon Solar Arrays

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The results for Task 3 of the Low Cost Solar Array Project are presented. Task 3 is directed toward the development of a cost effective encapsulating system for photovoltaic modules using silicon based materials. The technical approach of the contract effort is divided into four special tasks: (1) technology review; (2) generation of concepts for screening and processing silicon encapsulation systems; (3) assessment of encapsulation concepts; and (4) evaluation of encapsulation concepts. The candidate silicon materials are reviewed. The silicon and modified silicon resins were chosen on the basis of similarity to materials with known weatherability, cost, initial tangential modulus, accelerated dirt pick-up test results and the ratio of the content of organic phenyl substitution of methyl substitution on the backbone of the silicon resin.

  19. Edge determination for polycrystalline silicon lines on gate oxide

    NASA Astrophysics Data System (ADS)

    Villarrubia, John S.; Vladar, Andras E.; Lowney, Jeremiah R.; Postek, Michael T., Jr.

    2001-08-01

    In a scanning electron microscope (SEM) top-down secondary electron image, areas within a few tens of nanometers of the line edges are characteristically brighter than the rest of the image. In general, the shape of the secondary electron signal within such edge regions depends upon the energy and spatial distribution of the electron beam and the sample composition, and it is sensitive to small variations in sample geometry. Assigning edge shape and position is done by finding a model sample that is calculated, on the basis of a mathematical model of the instrument-sample interaction, to produce an image equal to the one actually observed. Edge locations, and consequently line widths, are then assigned based upon this model sample. In previous years we have applied this strategy to lines with geometry constrained by preferential etching of single crystal silicon. With this study we test the procedure on polycrystalline silicon lines. Polycrystalline silicon lines fabricated according to usual industrial processes represent a commercially interesting albeit technically more challenging application of this method. With the sample geometry less constrained a priori, a larger set of possible sample geometries must be modeled and tested for a match to the observed line scan, and the possibility of encountering multiple acceptable matches is increased. For this study we have implemented a data analysis procedure that matches measured image line scans to a precomputed library of sample shapes and their corresponding line scans. Linewidth test patterns containing both isolated and dense lines separated form the underlying silicon substrate by a thin gate oxide have been fabricated. Line scans from test pattern images have been fitted to the library of modeled shapes.

  20. Top-Coating Silicon Onto Ceramic

    NASA Technical Reports Server (NTRS)

    Heaps, J. D.; Nelson, L. D.; Zook, J. D.

    1985-01-01

    Polycrystalline silicon for solar cells produced at low cost. Molten silicon poured from quartz trough onto moving carbon-coated ceramic substrate. Doctor blade spreads liquid silicon evenly over substrate. Molten material solidifies to form sheet of polycrystalline silicon having photovoltaic conversion efficiency greater than 10 percent. Method produces 100-um-thick silicon coatings at speed 0.15 centimeter per second.

  1. Use of silicon in liquid sintered silicon nitrides and sialons

    DOEpatents

    Raj, R.; Baik, S.

    1984-12-11

    This invention relates to the production of improved high density nitrogen based ceramics by liquid-phase densification of silicon nitride or a compound of silicon-nitrogen-oxygen-metal, e.g. a sialon. In the process and compositions of the invention minor amounts of finely divided silicon are employed together with the conventional liquid phase producing additives to enhance the densification of the resultant ceramic. 4 figs.

  2. Use of silicon in liquid sintered silicon nitrides and sialons

    DOEpatents

    Raj, Rishi; Baik, Sunggi

    1984-12-11

    This invention relates to the production of improved high density nitrogen based ceramics by liquid-phase densification of silicon nitride or a compound of silicon-nitrogen-oxygen-metal, e.g. a sialon. In the process and compositions of the invention minor amounts of finely divided silicon are employed together with the conventional liquid phase producing additives to enhance the densification of the resultant ceramic.

  3. Rapid Silicon Dioxide Film Formation on Clean Silicon Surfaces

    DTIC Science & Technology

    1992-10-19

    devices, and demands for higher reliability, thereby requiring further refinements of silicon planar technology . An understanding of the kinetics of film...110)) reveal the dependence of the refractive index of SiO. as a function of oxide thickness. No orientation effects were found. Kinetic measurements...further refinements of silicon planar technology . An understanding of the kinetics of film formation and optical properties of ultrathin silicon

  4. Amorphous silicon radiation detectors

    DOEpatents

    Street, Robert A.; Perez-Mendez, Victor; Kaplan, Selig N.

    1992-01-01

    Hydrogenated amorphous silicon radiation detector devices having enhanced signal are disclosed. Specifically provided are transversely oriented electrode layers and layered detector configurations of amorphous silicon, the structure of which allow high electric fields upon application of a bias thereby beneficially resulting in a reduction in noise from contact injection and an increase in signal including avalanche multiplication and gain of the signal produced by incoming high energy radiation. These enhanced radiation sensitive devices can be used as measuring and detection means for visible light, low energy photons and high energy ionizing particles such as electrons, x-rays, alpha particles, beta particles and gamma radiation. Particular utility of the device is disclosed for precision powder crystallography and biological identification.

  5. Silicon Carbide Electronic Devices

    NASA Technical Reports Server (NTRS)

    Neudeck, P. G.

    2001-01-01

    The status of emerging silicon carbide (SiC) widebandgap semiconductor electronics technology is briefly surveyed. SiC-based electronic devices and circuits are being developed for use in high-temperature, high-power, and/or high-radiation conditions under which conventional semiconductors cannot function. Projected performance benefits of SiC electronics are briefly illustrated for several applications. However, most of these operational benefits of SiC have yet to be realized in actual systems, primarily owing to the fact that the growth techniques of SiC crystals are relatively immature and device fabrication technologies are not yet sufficiently developed to the degree required for widespread, reliable commercial use. Key crystal growth and device fabrication issues that limit the performance and capability of high-temperature and/or high-power SiC electronics are identified. The electrical and material quality differences between emerging SiC and mature silicon electronics technology are highlighted.

  6. Amorphous silicon radiation detectors

    DOEpatents

    Street, R.A.; Perez-Mendez, V.; Kaplan, S.N.

    1992-11-17

    Hydrogenated amorphous silicon radiation detector devices having enhanced signal are disclosed. Specifically provided are transversely oriented electrode layers and layered detector configurations of amorphous silicon, the structure of which allow high electric fields upon application of a bias thereby beneficially resulting in a reduction in noise from contact injection and an increase in signal including avalanche multiplication and gain of the signal produced by incoming high energy radiation. These enhanced radiation sensitive devices can be used as measuring and detection means for visible light, low energy photons and high energy ionizing particles such as electrons, x-rays, alpha particles, beta particles and gamma radiation. Particular utility of the device is disclosed for precision powder crystallography and biological identification. 13 figs.

  7. Silicon dendritic web material

    NASA Technical Reports Server (NTRS)

    Meier, D. L.; Campbell, R. B.; Sienkiewicz, L. J.; Rai-Choudhury, P.

    1982-01-01

    The development of a low cost and reliable contact system for solar cells and the fabrication of several solar cell modules using ultrasonic bonding for the interconnection of cells and ethylene vinyl acetate as the potting material for module encapsulation are examined. The cells in the modules were made from dendritic web silicon. To reduce cost, the electroplated layer of silver was replaced with an electroplated layer of copper. The modules that were fabricated used the evaporated Ti, Pd, Ag and electroplated Cu (TiPdAg/Cu) system. Adherence of Ni to Si is improved if a nickel silicide can be formed by heat treatment. The effectiveness of Ni as a diffusion barrier to Cu and the ease with which nickel silicide is formed is discussed. The fabrication of three modules using dendritic web silicon and employing ultrasonic bonding for interconnecting calls and ethylene vinyl acetate as the potting material is examined.

  8. Haematic silicon in drowning.

    PubMed

    Pierucci, Giovanni; Merlano, Federica; Chen, Yao; Sturini, Michela; Maraschi, Federica; Profumo, Antonella

    2016-04-01

    The aim of this paper was to evaluate silicon (Si) concentration in human whole ventricular blood as a further potential chemical marker in the diagnosis of drowning. We employed an acidic digestion for the extraction of soluble Si, and an alkaline digestion for the determination of total Si, including particulate matter, both arising from drowning medium. 29 suspected drowning situations, 24 in fresh water (Fw) and 5 in seawater (Sw), were examined. The difference in Si concentration between the left and right ventricular blood (Si ΔL-R) was measured and alkaline Si ΔL-R seems, indeed, a potentially significant complementary tool in the diagnosis of Fw drowning, because insoluble silicon fraction does not undergo hemo-dilution or hemo-concentration, and the ΔL-R is not affected by exogenous factors. In spite of the limited number of cases investigated, a good correlation was observed between the analytical results and the macro-microscopic autoptic findings.

  9. A silicon electromechanical photodetector.

    PubMed

    Tallur, Siddharth; Bhave, Sunil A

    2013-06-12

    Optomechanical systems have enabled wide-band optical frequency conversion and multichannel all-optical radio frequency amplification. Realization of an on-chip silicon communication platform is limited by photodetectors needed to convert optical information to electrical signals for further signal processing. In this paper we present a coupled silicon microresonator, which converts near-IR optical intensity modulation at 174.2 MHz and 1.198 GHz into motional electrical current. This device emulates a photodetector which detects intensity modulation of continuous wave laser light in the full-width-at-half-maximum bandwidth of the mechanical resonance. The resonant principle of operation eliminates dark current challenges associated with convetional photodetectors. While the results presented here constitute a purely classical demonstration, the device can also potentially be extended to the quantum regime to realize a photon-phonon translator.

  10. Germanium epitaxy on silicon

    PubMed Central

    Ye, Hui; Yu, Jinzhong

    2014-01-01

    With the rapid development of on-chip optical interconnects and optical computing in the past decade, silicon-based integrated devices for monolithic and hybrid optoelectronic integration have attracted wide attention. Due to its narrow pseudo-direct gap behavior and compatibility with Si technology, epitaxial Ge-on-Si has become a significant material for optoelectronic device applications. In this paper, we describe recent research progress on heteroepitaxy of Ge flat films and self-assembled Ge quantum dots on Si. For film growth, methods of strain modification and lattice mismatch relief are summarized, while for dot growth, key process parameters and their effects on the dot density, dot morphology and dot position are reviewed. The results indicate that epitaxial Ge-on-Si materials will play a bigger role in silicon photonics. PMID:27877657

  11. Multicolored Vertical Silicon Nanowires

    SciTech Connect

    Seo, Kwanyong; Wober, Munib; Steinvurzel, P.; Schonbrun, E.; Dan, Yaping; Ellenbogen, T.; Crozier, K. B.

    2011-04-13

    We demonstrate that vertical silicon nanowires take on a surprising variety of colors covering the entire visible spectrum, in marked contrast to the gray color of bulk silicon. This effect is readily observable by bright-field microscopy, or even to the naked eye. The reflection spectra of the nanowires each show a dip whose position depends on the nanowire radii. We compare the experimental data to the results of finite difference time domain simulations to elucidate the physical mechanisms behind the phenomena we observe. The nanowires are fabricated as arrays, but the vivid colors arise not from scattering or diffractive effects of the array, but from the guided mode properties of the individual nanowires. Each nanowire can thus define its own color, allowing for complex spatial patterning. We anticipate that the color filter effect we demonstrate could be employed in nanoscale image sensor devices.

  12. Germanium epitaxy on silicon.

    PubMed

    Ye, Hui; Yu, Jinzhong

    2014-04-01

    With the rapid development of on-chip optical interconnects and optical computing in the past decade, silicon-based integrated devices for monolithic and hybrid optoelectronic integration have attracted wide attention. Due to its narrow pseudo-direct gap behavior and compatibility with Si technology, epitaxial Ge-on-Si has become a significant material for optoelectronic device applications. In this paper, we describe recent research progress on heteroepitaxy of Ge flat films and self-assembled Ge quantum dots on Si. For film growth, methods of strain modification and lattice mismatch relief are summarized, while for dot growth, key process parameters and their effects on the dot density, dot morphology and dot position are reviewed. The results indicate that epitaxial Ge-on-Si materials will play a bigger role in silicon photonics.

  13. Germanium epitaxy on silicon

    NASA Astrophysics Data System (ADS)

    Ye, Hui; Yu, Jinzhong

    2014-04-01

    With the rapid development of on-chip optical interconnects and optical computing in the past decade, silicon-based integrated devices for monolithic and hybrid optoelectronic integration have attracted wide attention. Due to its narrow pseudo-direct gap behavior and compatibility with Si technology, epitaxial Ge-on-Si has become a significant material for optoelectronic device applications. In this paper, we describe recent research progress on heteroepitaxy of Ge flat films and self-assembled Ge quantum dots on Si. For film growth, methods of strain modification and lattice mismatch relief are summarized, while for dot growth, key process parameters and their effects on the dot density, dot morphology and dot position are reviewed. The results indicate that epitaxial Ge-on-Si materials will play a bigger role in silicon photonics.

  14. Silicon-Based Oxide/Silicon/Oxide Resonant Tunneling

    DTIC Science & Technology

    1998-03-01

    approximately 0.5 eV in the limit of high Ge content where only thin layers can be grown without lattice relaxation. Silicon germanium and its alloys...FINAL REPORT FOR SILICON -BASED OXIDE/ SILICON /OXIDE RESONANT TUNNELING CONTRACT NO. F49620-95-C-0001 1 December 1994 - 31 March 1998 Prepared For...RSSilicon-Based Oxide/ Silicon /Oxide Re sonant Tunneling 61102F L Aurkaft-n2305/CS Dr Seabaugh 7. MORMIG VIGNIIIO;NAME(S) 1 GRISS(ES) Pf~fOMING ORGANIZATION

  15. Porous silicon-based rugate filters.

    PubMed

    Lorenzo, Eduardo; Oton, Claudio J; Capuj, Néstor E; Ghulinyan, Mher; Navarro-Urrios, Daniel; Gaburro, Zeno; Pavesi, Lorenzo

    2005-09-10

    We report an experimental study of porous silicon-based rugate filters. We performed filter apodization, following a half-apodization approach, which successfully attenuated the sidelobes at both sides of the photonic stop band. We achieved successful reduction of interference ripples through the insertion of index-matching layers on the first and last interfaces. An apodized dielectric mirror and a rugate filter are compared: Appreciable differences in the harmonic presence and stop-band performance were observed and are commented on. Bandwidth control when index contrast is modified is also demonstrated. Finally, the possibility of combining different rugate filter designs to attain more complex responses is demonstrated by the achievement of a multi-stop-band filter. Numerical calculations for design optimization and comparison with experimental data are reported too.

  16. Wide bandgap passivation layers on silicon

    NASA Astrophysics Data System (ADS)

    Case, C.; Landis, G.; Beaulieu, R.; Loferski, J.; Vernon, S. M.; Spitzer, M. B.; Sekula, P.; Keavney, C. J.; Haven, V.

    The research problem that has been addressed in this work is the deposition of ZnS, ZnS sub 0.9Se sub 0.1, and GaP, which are candidate lattice-matched wide bandgap materials intended to replace SiO2 passivation on silicon solar cells. Ideally, these films would reflect minority carriers but not impede majority carrier transport to the surface and would passivate beneath contacts. The thin films were deposited by MOCVD, resistance evaporation or sputtering. Epitaxial GaP and ZnS films cause increases of internal quantum efficiency at short wavelengths. Reductions in J sub o comparable to that generated by SiO2, and increases in V sub oc were also observed. Film growth morphology was found to be a function of substrate temperature, orientation and the success of in situ removal of the native oxide.

  17. Wide bandgap passivation layers on silicon

    NASA Astrophysics Data System (ADS)

    Case, C.; Landis, G.; Beaulieu, R.; Loferski, J.; Sekula, P.

    The research problem addressed is the deposition of ZnS, ZnS0.9Se0.1, and GaP, which are candidate lattice-matched wide-bandgap materials intended to replace SiO2 passivation on silicon solar cells. Ideally, these films would reflect minority carriers but not impede majority carrier transport to the surface and would passivate beneath contacts. The thin films were deposited by MOCVD, resistance evaporation or sputtering. Epitaxial GaP and ZnS films were found to cause increases of internal quantum efficiency at short wavelengths. Reductions in J0 comparable to that generated by SiO2 and increases in Voc were also observed. Film growth morphology was found to be a function of substrate temperature, orientation and the success of in situ removal of the native oxide.

  18. Silicon photonics manufacturing.

    PubMed

    Zortman, William A; Trotter, Douglas C; Watts, Michael R

    2010-11-08

    Most demonstrations in silicon photonics are done with single devices that are targeted for use in future systems. One of the costs of operating multiple devices concurrently on a chip in a system application is the power needed to properly space resonant device frequencies on a system's frequency grid. We asses this power requirement by quantifying the source and impact of process induced resonant frequency variation for microdisk resonators across individual die, entire wafers and wafer lots for separate process runs. Additionally we introduce a new technique, utilizing the Transverse Electric (TE) and Transverse Magnetic (TM) modes in microdisks, to extract thickness and width variations across wafers and dice. Through our analysis we find that a standard six inch Silicon on Insulator (SOI) 0.35 μm process controls microdisk resonant frequencies for the TE fundamental resonances to within 1 THz across a wafer and 105 GHz within a single die. Based on demonstrated thermal tuner technology, a stable manufacturing process exhibiting this level of variation can limit the resonance trimming power per resonant device to 231 μW. Taken in conjunction with the power to compensate for thermal environmental variations, the expected power requirement to compensate for fabrication-induced non-uniformities is 17% of that total. This leads to the prediction that thermal tuning efficiency is likely to have the most dominant impact on the overall power budget of silicon photonics resonator technology.

  19. Cross-validation of matching correlation analysis by resampling matching weights.

    PubMed

    Shimodaira, Hidetoshi

    2016-03-01

    The strength of association between a pair of data vectors is represented by a nonnegative real number, called matching weight. For dimensionality reduction, we consider a linear transformation of data vectors, and define a matching error as the weighted sum of squared distances between transformed vectors with respect to the matching weights. Given data vectors and matching weights, the optimal linear transformation minimizing the matching error is solved by the spectral graph embedding of Yan et al. (2007). This method is a generalization of the canonical correlation analysis, and will be called as matching correlation analysis (MCA). In this paper, we consider a novel sampling scheme where the observed matching weights are randomly sampled from underlying true matching weights with small probability, whereas the data vectors are treated as constants. We then investigate a cross-validation by resampling the matching weights. Our asymptotic theory shows that the cross-validation, if rescaled properly, computes an unbiased estimate of the matching error with respect to the true matching weights. Existing ideas of cross-validation for resampling data vectors, instead of resampling matching weights, are not applicable here. MCA can be used for data vectors from multiple domains with different dimensions via an embarrassingly simple idea of coding the data vectors. This method will be called as cross-domain matching correlation analysis (CDMCA), and an interesting connection to the classical associative memory model of neural networks is also discussed.

  20. Diamond-silicon carbide composite

    DOEpatents

    Qian, Jiang; Zhao, Yusheng

    2006-06-13

    Fully dense, diamond-silicon carbide composites are prepared from ball-milled microcrystalline diamond/amorphous silicon powder mixture. The ball-milled powder is sintered (P=5–8 GPa, T=1400K–2300K) to form composites having high fracture toughness. A composite made at 5 GPa/1673K had a measured fracture toughness of 12 MPa.dot.m1/2. By contrast, liquid infiltration of silicon into diamond powder at 5 GPa/1673K produces a composite with higher hardness but lower fracture toughness. X-ray diffraction patterns and Raman spectra indicate that amorphous silicon is partially transformed into nanocrystalline silicon at 5 GPa/873K, and nanocrystalline silicon carbide forms at higher temperatures.

  1. 7 CFR 3419.2 - Matching funds.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Matching funds. 3419.2 Section 3419.2 Agriculture... SERVICE, DEPARTMENT OF AGRICULTURE MATCHING FUNDS REQUIREMENT FOR AGRICULTURAL RESEARCH AND EXTENSION FORMULA FUNDS AT 1890 LAND-GRANT INSTITUTIONS, INCLUDING TUSKEGEE UNIVERSITY, AND AT 1862...

  2. 24 CFR 576.51 - Matching funds.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 3 2010-04-01 2010-04-01 false Matching funds. 576.51 Section 576... Program Requirements § 576.51 Matching funds. (a) General. (1) Each grantee, other than a territory, must... that a grantee may use funds from any source, including any other federal source (but excluding...

  3. 7 CFR 3430.906 - Matching requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Matching requirements. 3430.906 Section 3430.906 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD AND... ADMINISTRATIVE PROVISIONS New Era Rural Technology Competitive Grants Program § 3430.906 Matching...

  4. 7 CFR 3430.906 - Matching requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Matching requirements. 3430.906 Section 3430.906 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD AND... ADMINISTRATIVE PROVISIONS New Era Rural Technology Competitive Grants Program § 3430.906 Matching...

  5. 7 CFR 3430.906 - Matching requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Matching requirements. 3430.906 Section 3430.906 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD AND... ADMINISTRATIVE PROVISIONS New Era Rural Technology Competitive Grants Program § 3430.906 Matching...

  6. 7 CFR 3430.906 - Matching requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Matching requirements. 3430.906 Section 3430.906 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD AND... ADMINISTRATIVE PROVISIONS New Era Rural Technology Competitive Grants Program § 3430.906 Matching...

  7. How Important Is a Cricket Test Match?

    ERIC Educational Resources Information Center

    Glaister, P.

    2007-01-01

    In this article, the author analyzes the cricket series match between England and Australia by applying the concept of probability. The author presents solutions for obtaining results of either team winning or both ending up in a draw in the situation of a five-match series. The author also analyzes the probability wherein the series is still…

  8. Active impedance matching of complex structural systems

    NASA Technical Reports Server (NTRS)

    Macmartin, Douglas G.; Miller, David W.; Hall, Steven R.

    1991-01-01

    Viewgraphs on active impedance matching of complex structural systems are presented. Topics covered include: traveling wave model; dereverberated mobility model; computation of dereverberated mobility; control problem: optimal impedance matching; H2 optimal solution; statistical energy analysis (SEA) solution; experimental transfer functions; interferometer actuator and sensor locations; active strut configurations; power dual variables; dereverberation of complex structure; dereverberated transfer function; compensators; and relative power flow.

  9. 28 CFR 33.21 - Match.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Match. 33.21 Section 33.21 Judicial Administration DEPARTMENT OF JUSTICE BUREAU OF JUSTICE ASSISTANCE GRANT PROGRAMS Criminal Justice Block Grants Allocation of Funds § 33.21 Match. (a) Funds may be used to pay up to 50 percent of the cost of a program...

  10. 7 CFR 3430.406 - Matching requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... ADMINISTRATIVE PROVISIONS Organic Agriculture Research and Extension Initiative § 3430.406 Matching requirements... 7 Agriculture 15 2012-01-01 2012-01-01 false Matching requirements. 3430.406 Section 3430.406 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD...

  11. 7 CFR 3430.406 - Matching requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... ADMINISTRATIVE PROVISIONS Organic Agriculture Research and Extension Initiative § 3430.406 Matching requirements... 7 Agriculture 15 2014-01-01 2014-01-01 false Matching requirements. 3430.406 Section 3430.406 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD...

  12. 7 CFR 3430.406 - Matching requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... ADMINISTRATIVE PROVISIONS Organic Agriculture Research and Extension Initiative § 3430.406 Matching requirements... 7 Agriculture 15 2013-01-01 2013-01-01 false Matching requirements. 3430.406 Section 3430.406 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD...

  13. Matching forensic sketches to mug shot photos.

    PubMed

    Klare, Brendan F; Li, Zhifeng; Jain, Anil K

    2011-03-01

    The problem of matching a forensic sketch to a gallery of mug shot images is addressed in this paper. Previous research in sketch matching only offered solutions to matching highly accurate sketches that were drawn while looking at the subject (viewed sketches). Forensic sketches differ from viewed sketches in that they are drawn by a police sketch artist using the description of the subject provided by an eyewitness. To identify forensic sketches, we present a framework called local feature-based discriminant analysis (LFDA). In LFDA, we individually represent both sketches and photos using SIFT feature descriptors and multiscale local binary patterns (MLBP). Multiple discriminant projections are then used on partitioned vectors of the feature-based representation for minimum distance matching. We apply this method to match a data set of 159 forensic sketches against a mug shot gallery containing 10,159 images. Compared to a leading commercial face recognition system, LFDA offers substantial improvements in matching forensic sketches to the corresponding face images. We were able to further improve the matching performance using race and gender information to reduce the target gallery size. Additional experiments demonstrate that the proposed framework leads to state-of-the-art accuracys when matching viewed sketches.

  14. Monkeys Match and Tally Quantities across Senses

    ERIC Educational Resources Information Center

    Jordan, Kerry E.; MacLean, Evan L.; Brannon, Elizabeth M.

    2008-01-01

    We report here that monkeys can actively match the number of sounds they hear to the number of shapes they see and present the first evidence that monkeys sum over sounds and sights. In Experiment 1, two monkeys were trained to choose a simultaneous array of 1-9 squares that numerically matched a sample sequence of shapes or sounds. Monkeys…

  15. 7 CFR 3405.5 - Matching funds.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Matching funds. 3405.5 Section 3405.5 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD AND AGRICULTURE HIGHER EDUCATION CHALLENGE GRANTS PROGRAM Program Description § 3405.5 Matching funds. Each application...

  16. 32 CFR 806b.50 - Computer matching.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... matching program must contact Air Force Chief Information Officer/P immediately. System managers must... National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE ADMINISTRATION PRIVACY ACT... information for use in a matching program. Send the proposed system notice to Air Force Chief...

  17. Anarchy, Stability, and Utopia: Creating Better Matchings

    NASA Astrophysics Data System (ADS)

    Anshelevich, Elliot; Das, Sanmay; Naamad, Yonatan

    We consider the loss in social welfare caused by individual rationality in matching scenarios. We give both theoretical and experimental results comparing stable matchings with socially optimal ones, as well as studying the convergence of various natural algorithms to stable matchings. Our main goal is to design mechanisms that incentivize agents to participate in matchings that are socially desirable. We show that theoretically, the loss in social welfare caused by strategic behavior can be substantial. However, under some natural distributions of utilities, we show experimentally that stable matchings attain close to the optimal social welfare. Furthermore, for certain graph structures, simple greedy algorithms for partner-switching (some without convergence guarantees) converge to stability remarkably quickly in expectation. Even when stable matchings are significantly socially suboptimal, slight changes in incentives can provide good solutions. We derive conditions for the existence of approximately stable matchings that are also close to socially optimal, which demonstrates that adding small switching costs can make socially optimal matchings stable.

  18. 7 CFR 3430.406 - Matching requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... ADMINISTRATIVE PROVISIONS Organic Agriculture Research and Extension Initiative § 3430.406 Matching requirements... 7 Agriculture 15 2011-01-01 2011-01-01 false Matching requirements. 3430.406 Section 3430.406 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD...

  19. Face matching impairment in developmental prosopagnosia.

    PubMed

    White, David; Rivolta, Davide; Burton, A Mike; Al-Janabi, Shahd; Palermo, Romina

    2017-02-01

    Developmental prosopagnosia (DP) is commonly referred to as 'face blindness', a term that implies a perceptual basis to the condition. However, DP presents as a deficit in face recognition and is diagnosed using memory-based tasks. Here, we test face identification ability in six people with DP, who are severely impaired on face memory tasks, using tasks that do not rely on memory. First, we compared DP to control participants on a standardized test of unfamiliar face matching using facial images taken on the same day and under standardized studio conditions (Glasgow Face Matching Test; GFMT). Scores for DP participants did not differ from normative accuracy scores on the GFMT. Second, we tested face matching performance on a test created using images that were sourced from the Internet and so varied substantially due to changes in viewing conditions and in a person's appearance (Local Heroes Test; LHT). DP participants showed significantly poorer matching accuracy on the LHT than control participants, for both unfamiliar and familiar face matching. Interestingly, this deficit is specific to 'match' trials, suggesting that people with DP may have particular difficulty in matching images of the same person that contain natural day-to-day variations in appearance. We discuss these results in the broader context of individual differences in face matching ability.

  20. Variability of soccer referees' match performances.

    PubMed

    Weston, M; Drust, B; Atkinson, G; Gregson, W

    2011-03-01

    The aim of the present study was to determine the between-match variability in soccer referees' match performances. 1 269 individual match observations were undertaken on 59 referees (range 2-79 games per referee) officiating in the English Premier League and Championship from 2003/2004 to 2007/2008 using a computerised tracking system (Prozone (®), Leeds, England). Between-match coefficients of variation (CV) were calculated for all games and then compared between referee age and experience groups. High mean CVs were observed for high-speed running distance (25.9±10.1%), recovery time (32.7±13.8%), explosive sprints (34.3±16.6%), total number of sprints (54.0±20.7%) and number of match fouls (28±4.6%). Smaller CVs were observed for total distance covered (3.8±1.5%), top sprinting speed (5.6±10.9%), distance from the ball (4.2±1.9%) and the distance from fouls (9.9±4.3%). Variability in match activities was not influenced by referee age or experience. The present study's findings demonstrate that variability in soccer referees' match performances is high in some variables and not dependent on referee age or experience. Such variability means that research requires large sample sizes to detect real systematic changes in a number of performance characteristics when studied during matches.

  1. DOE/Industry Matching Grant Program

    SciTech Connect

    John C. Lee

    2003-09-30

    For the academic year 2001-2002, the Department of Nuclear Engineering and Radiological Sciences received $50,000 of industrial contributions, matched by a DOE grant of $35,000. We used the combined DOE/Industry Matching Grant of $85,000 toward (a) undergraduate merit scholarships and research support, (b) graduate student support, and (c) partial support of a research scientist.

  2. Auditory-Oral Matching Behavior in Newborns

    ERIC Educational Resources Information Center

    Chen, Xin; Striano, Tricia; Rakoczy, Hannes

    2004-01-01

    Twenty-five newborn infants were tested for auditory-oral matching behavior when presented with the consonant sound /m/ and the vowel sound /a/--a precursor behavior to vocal imitation. Auditory-oral matching behavior by the infant was operationally defined as showing the mouth movement appropriate for producing the model sound just heard (mouth…

  3. A TOMOGRAPHIC TECHNIQUE FOR MAGNETIZED BEAM MATCHING.

    SciTech Connect

    MONTAG,C.ET AL.

    2004-07-05

    To maintain low electron beam temperatures in the proposed RHIC electron cooler, careful matching of the magnetized beam from the source to the cooler solenoid is mandatory. We propose a tomographic technique to diagnose matching conditions. First simulation results will be presented.

  4. Under Match and the Community College Student

    ERIC Educational Resources Information Center

    Handel, Stephen J.

    2014-01-01

    This article defines the term "under matching" as the behavior in which mostly less-affluent, highly qualified high school graduates choose not to enroll at an institution that matches their qualifications--behavior which threatens their chances of earning a degree. The supporting research--rigorous, compelling, and…

  5. Fast Approximate Quadratic Programming for Graph Matching

    PubMed Central

    Vogelstein, Joshua T.; Conroy, John M.; Lyzinski, Vince; Podrazik, Louis J.; Kratzer, Steven G.; Harley, Eric T.; Fishkind, Donniell E.; Vogelstein, R. Jacob; Priebe, Carey E.

    2015-01-01

    Quadratic assignment problems arise in a wide variety of domains, spanning operations research, graph theory, computer vision, and neuroscience, to name a few. The graph matching problem is a special case of the quadratic assignment problem, and graph matching is increasingly important as graph-valued data is becoming more prominent. With the aim of efficiently and accurately matching the large graphs common in big data, we present our graph matching algorithm, the Fast Approximate Quadratic assignment algorithm. We empirically demonstrate that our algorithm is faster and achieves a lower objective value on over 80% of the QAPLIB benchmark library, compared with the previous state-of-the-art. Applying our algorithm to our motivating example, matching C. elegans connectomes (brain-graphs), we find that it efficiently achieves performance. PMID:25886624

  6. The Matching Law: A Tutorial for Practitioners

    PubMed Central

    Reed, Derek D; Kaplan, Brent A

    2011-01-01

    The application of the matching law has historically been limited to use as a quantitative measurement tool in the experimental analysis of behavior to describe temporally extended patterns of behavior-environment relations. In recent years, however, applications of the matching law have been translated to clinical settings and populations to gain a better understanding of how naturally-occurring events affect socially important behaviors. This tutorial provides a brief background of the conceptual foundations of matching, an overview of the various matching equations that have been used in research, and a description of how to interpret the data derived from these equations in the context of numerous examples of matching analyses conducted with socially important behavior. An appendix of resources is provided to direct readers to primary sources, as well as useful articles and books on the topic. PMID:22649575

  7. A New Approach for Semantic Web Matching

    NASA Astrophysics Data System (ADS)

    Zamanifar, Kamran; Heidary, Golsa; Nematbakhsh, Naser; Mardukhi, Farhad

    In this work we propose a new approach for semantic web matching to improve the performance of Web Service replacement. Because in automatic systems we should ensure the self-healing, self-configuration, self-optimization and self-management, all services should be always available and if one of them crashes, it should be replaced with the most similar one. Candidate services are advertised in Universal Description, Discovery and Integration (UDDI) all in Web Ontology Language (OWL). By the help of bipartite graph, we did the matching between the crashed service and a Candidate one. Then we chose the best service, which had the maximum rate of matching. In fact we compare two services' functionalities and capabilities to see how much they match. We found that the best way for matching two web services, is comparing the functionalities of them.

  8. Semantic Data Matching: Principles and Performance

    NASA Astrophysics Data System (ADS)

    Deaton, Russell; Doan, Thao; Schweiger, Tom

    Automated and real-time management of customer relationships requires robust and intelligent data matching across widespread and diverse data sources. Simple string matching algorithms, such as dynamic programming, can handle typographical errors in the data, but are less able to match records that require contextual and experiential knowledge. Latent Semantic Indexing (LSI) (Berry et al. ; Deerwester et al. is a machine intelligence technique that can match data based upon higher order structure, and is able to handle difficult problems, such as words that have different meanings but the same spelling, are synonymous, or have multiple meanings. Essentially, the technique matches records based upon context, or mathematically quantifying when terms occur in the same record.

  9. Fast approximate quadratic programming for graph matching.

    PubMed

    Vogelstein, Joshua T; Conroy, John M; Lyzinski, Vince; Podrazik, Louis J; Kratzer, Steven G; Harley, Eric T; Fishkind, Donniell E; Vogelstein, R Jacob; Priebe, Carey E

    2015-01-01

    Quadratic assignment problems arise in a wide variety of domains, spanning operations research, graph theory, computer vision, and neuroscience, to name a few. The graph matching problem is a special case of the quadratic assignment problem, and graph matching is increasingly important as graph-valued data is becoming more prominent. With the aim of efficiently and accurately matching the large graphs common in big data, we present our graph matching algorithm, the Fast Approximate Quadratic assignment algorithm. We empirically demonstrate that our algorithm is faster and achieves a lower objective value on over 80% of the QAPLIB benchmark library, compared with the previous state-of-the-art. Applying our algorithm to our motivating example, matching C. elegans connectomes (brain-graphs), we find that it efficiently achieves performance.

  10. Matching by linear programming and successive convexification.

    PubMed

    Jiang, Hao; Drew, Mark S; Li, Ze-Nian

    2007-06-01

    We present a novel convex programming scheme to solve matching problems, focusing on the challenging problem of matching in a large search range and with cluttered background. Matching is formulated as metric labeling with L1 regularization terms, for which we propose a novel linear programming relaxation method and an efficient successive convexification implementation. The unique feature of the proposed relaxation scheme is that a much smaller set of basis labels is used to represent the original label space. This greatly reduces the size of the searching space. A successive convexification scheme solves the labeling problem in a coarse to fine manner. Importantly, the original cost function is reconvexified at each stage, in the new focus region only, and the focus region is updated so as to refine the searching result. This makes the method well-suited for large label set matching. Experiments demonstrate successful applications of the proposed matching scheme in object detection, motion estimation, and tracking.

  11. Epitaxial Silicon Doped With Antimony

    NASA Technical Reports Server (NTRS)

    Huffman, James E.; Halleck, Bradley L.

    1996-01-01

    High-purity epitaxial silicon doped with antimony made by chemical vapor deposition, using antimony pentachloride (SbCI5) as source of dopant and SiH4, SiCI2H2, or another conventional source of silicon. High purity achieved in layers of arbitrary thickness. Epitaxial silicon doped with antimony needed to fabricate impurity-band-conduction photodetectors operating at wavelengths from 2.5 to 40 micrometers.

  12. Shock compression of [001] single crystal silicon

    DOE PAGES

    Zhao, S.; Remington, B.; Hahn, E. N.; ...

    2016-03-14

    Silicon is ubiquitous in our advanced technological society, yet our current understanding of change to its mechanical response at extreme pressures and strain-rates is far from complete. This is due to its brittleness, making recovery experiments difficult. High-power, short-duration, laser-driven, shock compression and recovery experiments on [001] silicon (using impedance-matched momentum traps) unveiled remarkable structural changes observed by transmission electron microscopy. As laser energy increases, corresponding to an increase in peak shock pressure, the following plastic responses are are observed: surface cleavage along {111} planes, dislocations and stacking faults; bands of amorphized material initially forming on crystallographic orientations consistent withmore » dislocation slip; and coarse regions of amorphized material. Molecular dynamics simulations approach equivalent length and time scales to laser experiments and reveal the evolution of shock-induced partial dislocations and their crucial role in the preliminary stages of amorphization. Furthermore, application of coupled hydrostatic and shear stresses produce amorphization below the hydrostatically determined critical melting pressure under dynamic shock compression.« less

  13. Shock compression of [001] single crystal silicon

    SciTech Connect

    Zhao, S.; Remington, B.; Hahn, E. N.; Kad, B.; Bringa, E. M.; Meyers, M. A.

    2016-03-14

    Silicon is ubiquitous in our advanced technological society, yet our current understanding of change to its mechanical response at extreme pressures and strain-rates is far from complete. This is due to its brittleness, making recovery experiments difficult. High-power, short-duration, laser-driven, shock compression and recovery experiments on [001] silicon (using impedance-matched momentum traps) unveiled remarkable structural changes observed by transmission electron microscopy. As laser energy increases, corresponding to an increase in peak shock pressure, the following plastic responses are are observed: surface cleavage along {111} planes, dislocations and stacking faults; bands of amorphized material initially forming on crystallographic orientations consistent with dislocation slip; and coarse regions of amorphized material. Molecular dynamics simulations approach equivalent length and time scales to laser experiments and reveal the evolution of shock-induced partial dislocations and their crucial role in the preliminary stages of amorphization. Furthermore, application of coupled hydrostatic and shear stresses produce amorphization below the hydrostatically determined critical melting pressure under dynamic shock compression.

  14. Silicon-on-insulator integrated optic transceivers

    NASA Astrophysics Data System (ADS)

    Morris, Robin J.

    1997-04-01

    Silicon-on-insulator offers the chance to produce integrated optical `circuits' with properties which are appropriate even for demanding applications. Developments in SOI waveguide technology have been combined with the well- developed micro-engineering properties of silicon for use in fields such as telecommunication and sensors. An integrated optical transceiver is selected as an example with which to describe the features of the technology. The design will be used to illustrate the benefits brought by the use of SOI waveguide elements. These functional `building blocks' include alignment features, integrated mode-matching waveguide tapers, tap-off couplers and low back-reflection interfaces. Further possible integrated elements are described, including WDMs, as relevant to optical transceiver technology. The economic and technical drivers and difficulties surrounding the convergence of electrical, CMOS-like and optical SOI technologies are also considered. There is a spreading acceptance that low-cost motherboard technology is needed, to realize volume production of optical transceivers. A range of materials solutions have been reported. The relative merits of SOI technology are discussed. Motherboard techniques provide a platform for precise optical alignment between components. The SOI approach can deliver self-aligned waveguide and hybridization features--such as fiber attach or laser diode connections--and includes the ability to adapt to laser diode and optical fiber near-field characteristics.

  15. Shock compression of [001] single crystal silicon

    NASA Astrophysics Data System (ADS)

    Zhao, S.; Hahn, E. N.; Kad, B.; Remington, B. A.; Bringa, E. M.; Meyers, M. A.

    2016-05-01

    Silicon is ubiquitous in our advanced technological society, yet our current understanding of change to its mechanical response at extreme pressures and strain-rates is far from complete. This is due to its brittleness, making recovery experiments difficult. High-power, short-duration, laser-driven, shock compression and recovery experiments on [001] silicon (using impedance-matched momentum traps) unveiled remarkable structural changes observed by transmission electron microscopy. As laser energy increases, corresponding to an increase in peak shock pressure, the following plastic responses are are observed: surface cleavage along {111} planes, dislocations and stacking faults; bands of amorphized material initially forming on crystallographic orientations consistent with dislocation slip; and coarse regions of amorphized material. Molecular dynamics simulations approach equivalent length and time scales to laser experiments and reveal the evolution of shock-induced partial dislocations and their crucial role in the preliminary stages of amorphization. Application of coupled hydrostatic and shear stresses produce amorphization below the hydrostatically determined critical melting pressure under dynamic shock compression.

  16. Silicon-on ceramic process. Silicon sheet growth and device developmentt for the Large-Area Silicon Sheet Task of the Low-Cost Solar Array Project. Quarterly report No. 13, October 1-December 31, 1979

    SciTech Connect

    Chapman, P W; Zook, J D; Grung, B L; McHenry, K; Schuldt, S B

    1980-02-15

    Research on the technical and economic feasibility of producing solar-cell-quality sheet silicon by coating inexpensive ceramic substrates with a thin layer of polycrystalline silicon is reported. The coating methods to be developed are directed toward a minimum-cost process for producing solar cells with a terrestrial conversion efficiency of 11 percent or greater. By applying a graphite coating to one face of a ceramic substrate, molten silicon can be caused to wet only that graphite-coated face and produce uniform thin layers of large-grain polycrystalline silicon; thus, only a minimal quantity of silicon is consumed. A variety of ceramic materials have been dip coated with silicon. The investigation has shown that mullite substrates containing an excess of SiO/sub 2/ best match the thermal expansion coefficient of silicon and hence produce the best SOC layers. With such substrates, smooth and uniform silicon layers 25 cm/sup 2/ in area have been achieved with single-crystal grains as large as 4 mm in width and several cm in length. Crystal length is limited by the length of the substrate. The thickness of the coating and the size of the crystalline grains are controlled by the temperature of the melt and the rate at which the substrate is withdrawn from the melt. The solar-cell potential of this SOC sheet silicon is promising. To date, solar cells with areas from 1 to 10 cm/sup 2/ have been fabricated from material with an as-grown surface. Conversion efficiencies of about 10 percent with antireflection (AR) coating have been achieved. Such cells typically have open-circuit voltage and short-circuit current densities of 0.55V and 23 mA/cm/sup 2/, respectively.

  17. Substrate for silicon solar cells

    SciTech Connect

    Thomas, D.E.

    1983-09-06

    A substrate is made for silicon solar cells by heating a sheet of large-grained silicon steel at a temperature of at least about 1300/sup 0/ C. in an atmosphere of hydrogen and tungsten hexafluoride (or hexachloride) at a partial pressure ratio of hydrogen to tungsten hexafluoride of about 3 to about 6 to deposit an epitaxial layer of tungsten on said sheet of silicon steel. Epitaxial silicon can then be deposited in a conventional manner on the layer of epitaxial tungsten.

  18. Single crystalline mesoporous silicon nanowires

    SciTech Connect

    Hochbaum, Allon; Dargas, Daniel; Hwang, Yun Jeong; Yang, Peidong

    2009-08-18

    Herein we demonstrate a novel electroless etching synthesis of monolithic, single-crystalline, mesoporous silicon nanowire arrays with a high surface area and luminescent properties consistent with conventional porous silicon materials. The photoluminescence of these nanowires suggest they are composed of crystalline silicon with small enough dimensions such that these arrays may be useful as photocatalytic substrates or active components of nanoscale optoelectronic devices. A better understanding of this electroless route to mesoporous silicon could lead to facile and general syntheses of different narrow bandgap semiconductor nanostructures for various applications.

  19. Silicon crystal growth in vacuum

    NASA Technical Reports Server (NTRS)

    Khattak, C. P.; Schmid, F.

    1982-01-01

    The most developed process for silicon crystal growth is the Czochralski (CZ) method which was in production for over two decades. In an effort to reduce cost of single crystal silicon for photovoltaic applications, a directional solidification technique, Heat Exchanger Method (HEM), was adapted. Materials used in HEM and CZ furnaces are quite similar (heaters, crucibles, insulation, etc.). To eliminate the cost of high purity argon, it was intended to use vacuum operation in HEM. Two of the major problems encountered in vacuum processing of silicon are crucible decomposition and silicon carbide formation in the melt.

  20. Solar silicon from directional solidification of MG silicon produced via the silicon carbide route

    NASA Technical Reports Server (NTRS)

    Rustioni, M.; Margadonna, D.; Pirazzi, R.; Pizzini, S.

    1986-01-01

    A process of metallurgical grade (MG) silicon production is presented which appears particularly suitable for photovoltaic (PV) applications. The MG silicon is prepared in a 240 KVA, three electrode submerged arc furnace, starting from high grade quartz and high purity silicon carbide. The silicon smelted from the arc furnace was shown to be sufficiently pure to be directionally solidified to 10 to 15 kg. After grinding and acid leaching, had a material yield larger than 90%. With a MG silicon feedstock containing 3 ppmw B, 290 ppmw Fe, 190 ppmw Ti, and 170 ppmw Al, blended with 50% of off grade electronic grade (EG) silicon to reconduct the boron content to a concentration acceptable for solar cell fabrication, the 99% of deep level impurities were concentrated in the last 5% of the ingot. Quite remarkably this material has OCV values higher tham 540 mV and no appreciable shorts due to SiC particles.

  1. Superconducting Super Collider silicon tracking subsystem research and development

    SciTech Connect

    Miller, W.O.; Thompson, T.C.; Ziock, H.J. ); Gamble, M.T. . Dept. of Materials Science and Engineering)

    1990-12-01

    The Alamos National Laboratory Mechanical Engineering and Electronics Division has been investigating silicon-based elementary particle tracking device technology as part of the Superconducting Super Collider-sponsored silicon subsystem collaboration. Structural, materials, and thermal issues have been addressed. This paper explores detector structural integrity and stability, including detailed finite element models of the silicon wafer support and predictive methods used in designing with advanced composite materials. The current design comprises a magnesium metal matrix composite (MMC) truss space frame to provide a sparse support structure for the complex array of silicon detectors. This design satisfies the 25-{mu}m structural stability requirement in a 10-Mrad radiation environment. This stability is achieved without exceeding the stringent particle interaction constraints set at 2.5% of a radiation length. Materials studies have considered thermal expansion, elastic modulus, resistance to radiation and chemicals, and manufacturability of numerous candidate materials. Based on optimization of these parameters, the MMC space frame will possess a coefficient of thermal expansion (CTE) near zero to avoid thermally induced distortions, whereas the cooling rings, which support the silicon detectors and heat pipe network, will probably be constructed of a graphite/epoxy composite whose CTE is engineered to match that of silicon. Results from radiation, chemical, and static loading tests are compared with analytical predictions and discussed. Electronic thermal loading and its efficient dissipation using heat pipe cooling technology are discussed. Calculations and preliminary designs for a sprayed-on graphite wick structure are presented. A hydrocarbon such as butane appears to be a superior choice of heat pipe working fluid based on cooling, handling, and safety criteria.

  2. Fluidized-Bed Particles Scavenge Silicon Fines

    NASA Technical Reports Server (NTRS)

    Hsu, G. C.; Rohatgi, N.; Lutwack, R.; Hogle, R.

    1985-01-01

    Waste reduced, and silicon production rate improved. In new process silicon formed by thermal decomposition of SiH4. Part of silicon formed on silicon seed particles as result of surface chemical reaction. However, silicon formed by homogeneous reaction in gas phase tends to form aggregates of silicon atoms, which appear as fine particles (like dust). Believed that scavenging action of seed particles enables large fraction fines to be incorporated onto seed surface. This mode of growth confirmed by electron microscopy photographs.

  3. Fluidized bed for production of polycrystalline silicon

    SciTech Connect

    Flagella, R.N.

    1992-08-18

    This patent describes a method for removing silicon powder particles from a reactor that produces polycrystalline silicon by the pyrolysis of a silane containing gas in a fluidized bed reaction zone of silicon seed particles. It comprises introducing the silane containing gas stream into the reaction zone of fluidized silicon seed particles; heterogeneously decomposing the silane containing gas under conditions; collecting the silicon product particles from the collection zone; and removing silicon powder particles from the reactor.

  4. 78 FR 48169 - Privacy Act of 1974; CMS Computer Match No. 2013-02; HHS Computer Match No. 1306; DoD-DMDC Match...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-07

    ... Services Privacy Act of 1974; CMS Computer Match No. 2013-02; HHS Computer Match No. 1306; DoD-DMDC Match... Services (CMS). ACTION: Notice of Computer Matching Program (CMP). SUMMARY: In accordance with the... INFORMATION: The Computer Matching and Privacy Protection Act of 1988 (Public Law (Pub. L.) 100-503),...

  5. Human-eye versus computerized color matching.

    PubMed

    Yap, A U; Sim, C P; Loh, W L; Teo, J H

    1999-01-01

    This project compared the difference in color matching between human-eye assessment and computerized colorimetry. Fifty dental personnel were asked to color match Vita Lumin shade tabs to seven different randomly arranged test tabs from the Z100 shade guide. All evaluators were blinded to the shades of the test tabs and were asked to match only body shade of the Vita Lumin tab to the middle third or body of each test tab. The results obtained were subsequently computed into L*a*b* values and compared with results obtained by computerized colorimetry. Results indicate that the difference in color matching between human-eye assessment and computerized colorimetry is shade dependent. Discrepancy was significant for b* coordinates for shades A1 and B2 and L* and b* coordinates for shade C4. For all shades evaluated, color difference between human-eye and computerized color matching is perceivable under clinical settings, as delta E values are greater than 3. There is a need for correction factors in the formal specification of the color-matching software due to the discrepancy between human-eye and computerized colorimetric color matching.

  6. Robust Face Image Matching under Illumination Variations

    NASA Astrophysics Data System (ADS)

    Yang, Chyuan-Huei Thomas; Lai, Shang-Hong; Chang, Long-Wen

    2004-12-01

    Face image matching is an essential step for face recognition and face verification. It is difficult to achieve robust face matching under various image acquisition conditions. In this paper, a novel face image matching algorithm robust against illumination variations is proposed. The proposed image matching algorithm is motivated by the characteristics of high image gradient along the face contours. We define a new consistency measure as the inner product between two normalized gradient vectors at the corresponding locations in two images. The normalized gradient is obtained by dividing the computed gradient vector by the corresponding locally maximal gradient magnitude. Then we compute the average consistency measures for all pairs of the corresponding face contour pixels to be the robust matching measure between two face images. To alleviate the problem due to shadow and intensity saturation, we introduce an intensity weighting function for each individual consistency measure to form a weighted average of the consistency measure. This robust consistency measure is further extended to integrate multiple face images of the same person captured under different illumination conditions, thus making our robust face matching algorithm. Experimental results of applying the proposed face image matching algorithm on some well-known face datasets are given in comparison with some existing face recognition methods. The results show that the proposed algorithm consistently outperforms other methods and achieves higher than 93% recognition rate with three reference images for different datasets under different lighting conditions.

  7. Silicon on insulator with active buried regions

    DOEpatents

    McCarthy, Anthony M.

    1996-01-01

    A method for forming patterned buried components, such as collectors, sources and drains, in silicon-on-insulator (SOI) devices. The method is carried out by epitaxially growing a suitable sequence of single or multiple etch stop layers ending with a thin silicon layer on a silicon substrate, masking the silicon such that the desired pattern is exposed, introducing dopant and activating in the thin silicon layer to form doped regions. Then, bonding the silicon layer to an insulator substrate, and removing the silicon substrate. The method additionally involves forming electrical contact regions in the thin silicon layer for the buried collectors.

  8. Silicon on insulator with active buried regions

    DOEpatents

    McCarthy, A.M.

    1998-06-02

    A method is disclosed for forming patterned buried components, such as collectors, sources and drains, in silicon-on-insulator (SOI) devices. The method is carried out by epitaxially growing a suitable sequence of single or multiple etch stop layers ending with a thin silicon layer on a silicon substrate, masking the silicon such that the desired pattern is exposed, introducing dopant and activating in the thin silicon layer to form doped regions. Then, bonding the silicon layer to an insulator substrate, and removing the silicon substrate. The method additionally involves forming electrical contact regions in the thin silicon layer for the buried collectors. 10 figs.

  9. Silicon on insulator with active buried regions

    DOEpatents

    McCarthy, A.M.

    1996-01-30

    A method is disclosed for forming patterned buried components, such as collectors, sources and drains, in silicon-on-insulator (SOI) devices. The method is carried out by epitaxially growing a suitable sequence of single or multiple etch stop layers ending with a thin silicon layer on a silicon substrate, masking the silicon such that the desired pattern is exposed, introducing dopant and activating in the thin silicon layer to form doped regions. Then, bonding the silicon layer to an insulator substrate, and removing the silicon substrate. The method additionally involves forming electrical contact regions in the thin silicon layer for the buried collectors. 10 figs.

  10. Silicon on insulator with active buried regions

    DOEpatents

    McCarthy, Anthony M.

    1998-06-02

    A method for forming patterned buried components, such as collectors, sources and drains, in silicon-on-insulator (SOI) devices. The method is carried out by epitaxially growing a suitable sequence of single or multiple etch stop layers ending with a thin silicon layer on a silicon substrate, masking the silicon such that the desired pattern is exposed, introducing dopant and activating in the thin silicon layer to form doped regions. Then, bonding the silicon layer to an insulator substrate, and removing the silicon substrate. The method additionally involves forming electrical contact regions in the thin silicon layer for the buried collectors.

  11. Illumination-invariant face recognition with a contrast sensitive silicon retina

    SciTech Connect

    Buhmann, J.M.; Lades, M.; Eeckman, F.

    1993-11-29

    Changes in lighting conditions strongly effect the performance and reliability of computer vision systems. We report face recognition results under drastically changing lighting conditions for a computer vision system which concurrently uses a contrast sensitive silicon retina and a conventional, gain controlled CCD camera. For both input devices the face recognition system employs an elastic matching algorithm with wavelet based features to classify unknown faces. To assess the effect of analog on-chip preprocessing by the silicon retina the CCD images have been digitally preprocessed with a bandpass filter to adjust the power spectrum. The silicon retina with its ability to adjust sensitivity increases the recognition rate up to 50 percent. These comparative experiments demonstrate that preprocessing with an analog VLSI silicon retina generates image data enriched with object-constant features.

  12. Electrodeposition at room temperature of amorphous silicon and germanium nanowires in ionic liquid

    NASA Astrophysics Data System (ADS)

    Martineau, F.; Namur, K.; Mallet, J.; Delavoie, F.; Endres, F.; Troyon, M.; Molinari, M.

    2009-11-01

    The electrodeposition at room temperature of silicon and germanium nanowires from the air- and water-stable ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (P1,4) containing SiCl4 as Si source or GeCl4 as Ge source is investigated by cyclic voltammetry. By using nanoporous polycarbonate membranes as templates, it is possible to reproducibly grow pure silicon and germanium nanowires of different diameters. The nanowires are composed of pure amorphous silicon or germanium. The nanowires have homogeneous cylindrical shape with a roughness of a few nanometres on the wire surfaces. The nanowires' diameters and lengths well match with the initial membrane characteristics. Preliminary photoluminescence experiments exhibit strong emission in the near infrared for the amorphous silicon nanowires.

  13. Low cost silicon solar array project silicon materials task

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A program was established to develop a high temperature silicon production process using existing electric arc heater technology. Silicon tetrachloride and a reductant will be injected into an arc heated mixture of hydrogen and argon. Under these high temperature conditions, a very rapid reaction is expected to occur and proceed essentially to completion, yielding silicon and gaseous sodium chloride. Techniques for high temperature separation and collection of the molten silicon will be developed using standard engineering approaches, and the salt vapor will later be electrolytically separated into its elemental constituents for recycle. Preliminary technical evaluations and economic projections indicate not only that this process appears to be feasible, but that it also has the advantages of rapid, high capacity production of good quality molten silicon at a nominal cost.

  14. New process of silicon carbide purification intended for silicon passivation

    NASA Astrophysics Data System (ADS)

    Barbouche, M.; Zaghouani, R. Benabderrahmane; Benammar, N. E.; Aglieri, V.; Mosca, M.; Macaluso, R.; Khirouni, K.; Ezzaouia, H.

    2017-01-01

    In this work, we report on a new, efficient and low cost process of silicon carbide (SiC) powder purification intended to be used in photovoltaic applications. This process consists on the preparation of porous silicon carbide layers followed by a photo-thermal annealing under oxygen atmosphere and chemical treatment. The effect of etching time on impurities removal efficiency was studied. Inductively coupled plasma atomic emission spectrometry (ICP-AES) results showed that the best result was achieved for an etching time of 10 min followed by gettering at 900 °C during 1 h. SiC purity is improved from 3N (99.9771%) to 4N (99.9946%). Silicon carbide thin films were deposited onto silicon substrates by pulsed laser deposition technique (PLD) using purified SiC powder as target. Significant improvement of the minority carrier lifetime was obtained encouraging the use of SiC as a passivation layer for silicon.

  15. SPIN MATCHING FROM AGS TO RHIC.

    SciTech Connect

    MACKAY,W.W.; TSOUPAS,N.

    2002-11-06

    With a partial Siberian snake in the AGS and transport lines with interspersed horizontal and vertical bends, the incoming spin direction at the injection points of both the collider rings is not likely to match the ideal vertical stable spin direction of RHIC which has two full helical Siberian snakes per ring. In this paper we examine the matching of a polarized beam transferred from the AGS into RHIC. The present 5% partial solenoidal snake as well as a proposed 20% superconducting helical are considered for the AGS. Solutions with retuned snakes in RHIC to better match the incoming beam have been found.

  16. D0 Silicon Upgrade: Thermally Induced Stresses in the Components of a D0 Ladder in the Silicon Tracker

    SciTech Connect

    Ratzmann, Paul M.; /Fermilab

    1996-07-02

    During the operation of the silicon tracker, the ladders will be in direct thermal contact with a cooling channel. The expected operating temperature of the cooling channel is 0 C, maintained by a cooling fluid whose bulk temperature is below 0 C. The assembly temperature is assumed to be 22 C. Due to the mis-match of material expansion coefficients, thermal stresses will be induced in the epoxy, beryllium, and silicon of the ladders. Calculations are presented here as well as some thermal cycling results on test samples. Shown in Figures 1 and 2 are perspective views of the top and bottom of a 3 chip ladder. The silicon temperature within the ladders will not be uniform due to the relative location of the heat dissipating components and the cooling channel. As an example the following plot demonstrates the expected temperature distribution in the 3 chip single sided ladder during operation. Under expected operating conditions of 0.75 W hybrid component power dissipation and 0.5 W per SVX II chip, the temperature profile is shown for two situations of how the ladder is constructed. The cooling channel corresponds roughly to locations on the silicon between 32 and 42 mm. The silicon in this region is sandwiched between two plates of beryllium and is about 4 C. For a construction temperature of 22 C the beryllium/silicon/beryllium assembly will see a 18 C change in temperature. To be conservative a 20 C temperature change will be assumed (some larger temperature extremes will be considered) within the ladder.

  17. ConfMatch: automating electron-density map interpretation by matching conformations.

    PubMed

    Wang, C E

    2000-12-01

    Building a protein model from the initial three-dimensional electron-density distribution (density map) is an important task in X-ray crystallography. This problem is computationally challenging because proteins are extremely flexible. The algorithm ConfMatch is a global real-space fitting procedure in torsion-angle space. It solves this 'map-interpretation' problem by matching a detailed conformation of the molecule to the density map (conformational matching). This 'best-match' structure is defined as one which maximizes the sum of the density at atom positions. ConfMatch is a practical systematic algorithm based on a branch-and-bound search. The most important idea of ConfMatch is an efficient method for computing accurate bounds. ConfMatch relaxes the conformational matching problem, a problem which can only be solved in exponential time, into one which can be solved in polynomial time. The solution to the relaxed problem is a guaranteed upper bound for the conformational matching problem. In most empirical cases, these bounds are accurate enough to prune the search space dramatically, enabling ConfMatch to solve structures with more than 100 free dihedral angles. Experiments have shown that ConfMatch may be able to automate the interpretation of density maps of small proteins.

  18. Surface breakdown of silicon

    NASA Astrophysics Data System (ADS)

    Feuerstein, R. J.; Senitzky, B.

    1991-07-01

    The surface electrical breakdown of n(+)nn(+) rectangular solid blocks of silicon was investigated. Studies were performed in air at pressures of 10 to the -6th torr and 1 atm, and in transformer oil, ethylene glycol, and deionized water, under pulsed electrical excitation. The breakdown voltage (BV) of these devices was found to increase as the dielectric constant of the ambient increased. Glow discharge cleaning of the surface in vacuum was found to have no effect on the BV. A theory of surface charging leading to field enhancement along the surface is developed on the basis of these findings.

  19. Silicon production process evaluations

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Chemical engineering analyses involving the preliminary process design of a plant (1,000 metric tons/year capacity) to produce silicon via the technology under consideration were accomplished. Major activities in the chemical engineering analyses included base case conditions, reaction chemistry, process flowsheet, material balance, energy balance, property data, equipment design, major equipment list, production labor and forward for economic analysis. The process design package provided detailed data for raw materials, utilities, major process equipment and production labor requirements necessary for polysilicon production in each process.

  20. Photoactive porous silicon nanopowder.

    PubMed

    Meekins, Benjamin H; Lin, Ya-Cheng; Manser, Joseph S; Manukyan, Khachatur; Mukasyan, Alexander S; Kamat, Prashant V; McGinn, Paul J

    2013-04-24

    Bulk processing of porous silicon nanoparticles (nSi) of 50-300 nm size and surface area of 25-230 m(2)/g has been developed using a combustion synthesis method. nSi exhibits consistent photoresponse to AM 1.5 simulated solar excitation. In confirmation of photoactivity, the films of nSi exhibit prompt bleaching following femtosecond laser pulse excitation resulting from the photoinduced charge separation. Photocurrent generation observed upon AM 1.5 excitation of these films in a photoelectrochemical cell shows strong dependence on the thickness of the intrinsic silica shell that encompasses the nanoparticles and hinders interparticle electron transfer.

  1. Silicon Web Process Development

    NASA Technical Reports Server (NTRS)

    Duncan, C. S.; Seidensticker, R. G.; Hopkins, R. H.; Mchugh, J. P.; Hill, F. E.; Heimlich, M. E.; Driggers, J. M.

    1978-01-01

    Progress in the development of techniques to grow silicon web at 25 wq cm/min output rate is reported. Feasibility of web growth with simultaneous melt replenishment is discussed. Other factors covered include: (1) tests of aftertrimmers to improve web width; (2) evaluation of growth lid designs to raise speed and output rate; (3) tests of melt replenishment hardware; and (4) investigation of directed gas flow systems to control unwanted oxide deposition in the system and to improve convective cooling of the web. Compatibility with sufficient solar cell performance is emphasized.

  2. Silicon carbide sewing thread

    NASA Technical Reports Server (NTRS)

    Sawko, Paul M. (Inventor)

    1995-01-01

    Composite flexible multilayer insulation systems (MLI) were evaluated for thermal performance and compared with currently used fibrous silica (baseline) insulation system. The systems described are multilayer insulations consisting of alternating layers of metal foil and scrim ceramic cloth or vacuum metallized polymeric films quilted together using ceramic thread. A silicon carbide thread for use in the quilting and the method of making it are also described. These systems provide lightweight thermal insulation for a variety of uses, particularly on the surface of aerospace vehicles subject to very high temperatures during flight.

  3. Silicon material task review

    NASA Technical Reports Server (NTRS)

    Lorenz, J. H.

    1986-01-01

    The objectives of the Flat-plate Solar Array (FSA) Project Silicon Material Task are to evaluate technologies, new and old; to develop the most promising technologies; to establish practicality of the processes to meet production, energy use, and economic criteria; and to develop an information base on impurities in polysilicon and to determine their effects on solar cell performance. The approach involves determining process feasibility, setting milestones for the forced selection of the processes, and establishing the technical readiness of the integrated process.

  4. Compensated amorphous silicon solar cell

    DOEpatents

    Carlson, David E.

    1980-01-01

    An amorphous silicon solar cell incorporates a region of intrinsic hydrogenated amorphous silicon fabricated by a glow discharge wherein said intrinsic region is compensated by P-type dopants in an amount sufficient to reduce the space charge density of said region under illumination to about zero.

  5. Luneburg lens in silicon photonics.

    PubMed

    Di Falco, Andrea; Kehr, Susanne C; Leonhardt, Ulf

    2011-03-14

    The Luneburg lens is an aberration-free lens that focuses light from all directions equally well. We fabricated and tested a Luneburg lens in silicon photonics. Such fully-integrated lenses may become the building blocks of compact Fourier optics on chips. Furthermore, our fabrication technique is sufficiently versatile for making perfect imaging devices on silicon platforms.

  6. The Impact of Silicon Photonics

    DTIC Science & Technology

    2007-08-29

    integrated photonics 16. SECURITY CLASSIFICATION OF: 17.LIMITATION OF ABSTRACT 18.NUMBER OF PAGES 19a. NAME OF RESPONSIBLE PERSON Richard Soref...The impact of present and potential applications is discussed. key words: silicon, optoelectronics, integrated photonics 1. Introduction Silicon

  7. Low cost silicon solar arrays

    NASA Technical Reports Server (NTRS)

    Goldsmith, J. V.; Cleland, J. W.; Westbrook, R. D.; Davis, H. L.; Wood, R. F.; Lindmayer, J.; Wakefield, G. F.

    1975-01-01

    The economic production of silicon solar cell arrays circumvents p-n junction degradation by nuclear doping, in which the Si-30 transmutes to P-31 after thermal neutron capture. Also considered are chemical purity specifications for improved silicon bulk states, surface induced states, and surface states.

  8. Hydrogen-silicon carbide interactions

    NASA Technical Reports Server (NTRS)

    Eckel, Andrew J.; Jacobson, Nathan S.; Misra, Ajay K.; Humphrey, Donald L.

    1989-01-01

    A study of the thermochemistry and kinetics of hydrogen environmental attack of silicon carbide was conducted for temperatures in the range from 1100 C to 1400 C. Thermodynamic maps based on the parameters of pressure and oxygen/moisture content were constructed. With increasing moisture levels, four distinct regions of attack were identified. Each region is defined by the thermodynamically stable solid phases. The theoretically stable solid phases of Region 1 are silicon carbide and silicon. Experimental evidence is provided to support this thermodynamic prediction. Silicon carbide is the single stable solid phase in Region 2. Active attack of the silicon carbide in this region occurs by the formation of gases of SiO, CO, CH4, SiH4, and SiH. Analysis of the kinetics of reaction for Region 2 at 1300 C show the attack of the silicon carbide to be controlled by gas phase diffusion of H2O to the sample. Silicon carbide and silica are the stable phases common to Regions 3 and 4. These two regions are characterized by the passive oxidation of silicon carbide and formation of a protective silica layer.

  9. Gettering Silicon Wafers with Phosphorus

    NASA Technical Reports Server (NTRS)

    Daiello, R. V.

    1983-01-01

    Silicon wafers subjected to gettering in phosphorus atmosphere have longer diffusion lengths and higher solar-cell efficiencies than untreated wafers. Gettering treatment improves properties of solar cells manufactured from impure silicon and is compatible with standard solar-cell processing.

  10. Smoother Scribing of Silicon Wafers

    NASA Technical Reports Server (NTRS)

    Danyluk, S.

    1986-01-01

    Proposed new tool used to scribe silicon wafers into chips more smoothly than before. New scriber produces surface that appears ductile. Scribed groove cuts have relatively smooth walls. Scriber consists of diamond pyramid point on rigid shaft. Ethanol flows through shaft and around point, like ink in ballpoint pen. Ethanol has significantly different effect for scribing silicon than water, used in conventional diamond scribers.

  11. Recent developments in silicon calorimetry

    SciTech Connect

    Brau, J.E.

    1990-11-01

    We present a survey of some of the recent calorimeter applications of silicon detectors. The numerous attractive features of silicon detectors are summarized, with an emphasis on those aspects important to calorimetry. Several of the uses of this technology are summarized and referenced. We consider applications for electromagnetic calorimetry, hadronic calorimetry, and proposals for the SSC.

  12. Cryolite Byproduct in Silicon Production

    NASA Technical Reports Server (NTRS)

    Bartlett, R. W.

    1982-01-01

    Process reacts alumina hydrate with HF and NaF from silicon-production process. Cryolite is produced by adding reaction step to process that makes high-purity silicon from fluorosilicic acid. New extended process has been demonstrated in laboratory and could be used in commercial plants.

  13. III-V/silicon germanium tandem solar cells on silicon substrates

    NASA Astrophysics Data System (ADS)

    Schmieder, Kenneth J.

    The development of a cost-effective high voltage tandem solar cell that can be grown directly on a silicon (Si) platform can lead to a 34% increase in efficiency over the present best monocrystalline Si laboratory device. III-V devices are known to yield some of the highest efficiencies in photovoltaics, but the high cost of lattice matched substrates and metal organic chemical vapor deposition (MOCVD) and device development make them prohibitively expensive in many markets. By utilizing silicon substrates and limiting the thickness of the III-V MOCVD material growth, this cost can be reduced. The leveraging technology of this initiative is a metamorphic silicon:germanium (SiGe) buffer between the silicon substrate and the active device layers. As developed by AmberWave Inc., it provides a low-dislocation interface for III-V nucleation and a high quality bottom cell grown by reduced pressure chemical vapor deposition (RPCVD). This research first reports on the theoretical limits of a III-V/SiGe tandem solar cell. Results will evaluate multiple III-V materials for the determination of optimal material composition to be lattice-matched with SiGe. Following this, a more complex device simulation, incorporating all major loss mechanisms, is accomplished in order to predict ideal efficiency targets and evaluate present experimental structures. Results demonstrate a robust model capable of simulating a wide range of binary and ternary III-V devices. Predictions show the capability of a tandem device operating at 32.5% 1-sun efficiency without requiring TDD improvement beyond that of the present SiGe layers. Following simulations, experimental III-V structures are grown via MOCVD and characterized, indicating successful process development for growth of III-V materials on the SiGe platform. This growth is then validated via the design and development of experimental solar device structures. Each iteration, beginning with the single-junction windowless GaAsP solar cell and

  14. Clothing Matching for Visually Impaired Persons

    PubMed Central

    Yuan, Shuai; Tian, YingLi; Arditi, Aries

    2012-01-01

    Matching clothes is a challenging task for many blind people. In this paper, we present a proof of concept system to solve this problem. The system consists of 1) a camera connected to a computer to perform pattern and color matching process; 2) speech commands for system control and configuration; and 3) audio feedback to provide matching results for both color and patterns of clothes. This system can handle clothes in deficient color without any pattern, as well as clothing with multiple colors and complex patterns to aid both blind and color deficient people. Furthermore, our method is robust to variations of illumination, clothing rotation and wrinkling. To evaluate the proposed prototype, we collect two challenging databases including clothes without any pattern, or with multiple colors and different patterns under different conditions of lighting and rotation. Results reported here demonstrate the robustness and effectiveness of the proposed clothing matching system. PMID:22523465

  15. 'T hooft anomaly matching for QCD

    SciTech Connect

    Terning, John

    1998-03-03

    I present a set of theories which display non-trivial 'tHooft anomaly matching for QCD with F flavors. The matching theories arenon-Abelian gauge theories with "dual" quarks and baryons, rather thanthe purely confining theories of baryons that 't Hooft originallysearched for. The matching gauge groups are required to have an Fpm 6dimensional representation. Such a correspondence is reminiscent ofSeiberg's duality for supersymmetric (SUSY) QCD, and these theories arecandidates for non-SUSY duality. However anomaly matching by itself isnot sufficiently restrictive, and duality for QCD cannot be establishedat present. At the very least, the existence of multiple anomaly matchingsolutions should provide a note of caution regarding conjectured non-SUSYdualities.

  16. Beam envelope matching for beam guidance systems

    SciTech Connect

    Brown, K.L.

    1980-08-01

    Ray optics and phase ellipse optics are developed as tools for designing charged particle beam guidance systems. Specific examples of basic optical systems and of phase ellipse matching are presented as illustrations of these mathematical techniques.

  17. Matching software practitioner needs to researcher activities

    NASA Technical Reports Server (NTRS)

    Feather, M. S.; Menzies, T.; Connelly, J. R.

    2003-01-01

    We present an approach to matching software practitioners' needs to software researchers' activities. It uses an accepted taxonomical software classfication scheme as intermediary, in terms of which practitioners express needs, and researchers express activities.

  18. On Stable Marriages and Greedy Matchings

    SciTech Connect

    Manne, Fredrik; Naim, Md; Lerring, Hakon; Halappanavar, Mahantesh

    2016-12-11

    Research on stable marriage problems has a long and mathematically rigorous history, while that of exploiting greedy matchings in combinatorial scientific computing is a younger and less developed research field. In this paper we consider the relationships between these two areas. In particular we show that several problems related to computing greedy matchings can be formulated as stable marriage problems and as a consequence several recently proposed algorithms for computing greedy matchings are in fact special cases of well known algorithms for the stable marriage problem. However, in terms of implementations and practical scalable solutions on modern hardware, the greedy matching community has made considerable progress. We show that due to the strong relationship between these two fields many of these results are also applicable for solving stable marriage problems.

  19. Clothing Matching for Visually Impaired Persons.

    PubMed

    Yuan, Shuai; Tian, Yingli; Arditi, Aries

    2011-01-01

    Matching clothes is a challenging task for many blind people. In this paper, we present a proof of concept system to solve this problem. The system consists of 1) a camera connected to a computer to perform pattern and color matching process; 2) speech commands for system control and configuration; and 3) audio feedback to provide matching results for both color and patterns of clothes. This system can handle clothes in deficient color without any pattern, as well as clothing with multiple colors and complex patterns to aid both blind and color deficient people. Furthermore, our method is robust to variations of illumination, clothing rotation and wrinkling. To evaluate the proposed prototype, we collect two challenging databases including clothes without any pattern, or with multiple colors and different patterns under different conditions of lighting and rotation. Results reported here demonstrate the robustness and effectiveness of the proposed clothing matching system.

  20. Mobile Application for Pesticide Label Matching

    EPA Pesticide Factsheets

    The label matching application will give inspectors the ability to instantly compare pesticide product labels against state and federal label databases via their cell phone, tablet or other mobile device.

  1. Compensated amorphous silicon solar cell

    DOEpatents

    Devaud, Genevieve

    1983-01-01

    An amorphous silicon solar cell including an electrically conductive substrate, a layer of glow discharge deposited hydrogenated amorphous silicon over said substrate and having regions of differing conductivity with at least one region of intrinsic hydrogenated amorphous silicon. The layer of hydrogenated amorphous silicon has opposed first and second major surfaces where the first major surface contacts the electrically conductive substrate and an electrode for electrically contacting the second major surface. The intrinsic hydrogenated amorphous silicon region is deposited in a glow discharge with an atmosphere which includes not less than about 0.02 atom percent mono-atomic boron. An improved N.I.P. solar cell is disclosed using a BF.sub.3 doped intrinsic layer.

  2. Silicone Granulomas, a Growing Problem?

    PubMed Central

    Curreri, Alexis T.; Taylor, Gina A.; Burris, Katy

    2016-01-01

    The formation of granulomas is known to be a possible adverse effect of liquid silicone administration, used for soft tissue augmentation. Its plumping effects provide enhancement of certain body parts, such as the lips, hips, and buttocks. The desire for enhancement, perhaps influenced by popular culture and an unrealistic standard of beauty, leads individuals to seek silicone injections. There is a growing population of women and men receiving injections by unlicensed, unskilled “practitioners” not related to the healthcare profession. Complications under such circumstances are not uncommon, particularly the emergence of silicone granulomas, and the authors’ medical center has seen an increase in such cases. In this case report, the authors illustrate a young patient with significant complications from her silicone injections, review current therapies for silicone granulomas, and discuss this growing medical problem. PMID:27386046

  3. Matching analysis on seven manufacturing CD SEMs

    NASA Astrophysics Data System (ADS)

    Bowley, Reginald R., Jr.; Beecher, James E.; Cogley, Robert M.; Dupuis, Sandra R.; Farrington, Dewey L.

    1998-06-01

    The control of critical dimensions is of primary importance in a semiconductor manufacturing line. While the use of level- dedicated CDSEMs assures maximum process control, it is preferable to use multiple CDSEMs interchangeably to minimize the effect of any CDSEM unavailability caused by systems being down, preventive maintenance, or when maximum flexibility and enhanced production throughput are required. Maintaining process control while measuring on multiple CDSEMs requires that CDSEM tool-to-tool matching of less than 5 nm be achieved and maintained. This paper describes a methodology whereby a seven-system CDSEM toolset is initially baselined to determine the subset(s) of systems which most closely match. A method of evaluating the inherent matching of seven OPALTM7830i CDSEMs within a single manufacturing facility is presented. The matching analysis was performed using a single production- level wafer, a level known to have previously exhibited poor matching results. All seven CDSEMs were networked to a common database server to insure that all measured consistently across the toolset. An experiment is described to ascertain the effects of multiple electron-beam measurements on this semiconductor sample and to evaluate any relative dimensional changes. A methodology for monitoring and controlling CDSEM system parameters during the matching evaluation is described. Finally, a procedure for determining the subset(s) of matched CDSEMs using analysis-of-variance (ANOVA), least significant difference (LSD, also known as a pairwise t-test) and Duncan's Multiple Range Test is presented. Using these methods, three subsets of systems are defined within the seven-system toolset that exhibited similar matching performance.

  4. Anomalous Plastic Deformation and Sputtering of Ion Irradiated Silicon Nanowires

    PubMed Central

    2015-01-01

    Silicon nanowires of various diameters were irradiated with 100 keV and 300 keV Ar+ ions on a rotatable and heatable stage. Irradiation at elevated temperatures above 300 °C retains the geometry of the nanostructure and sputtering can be gauged accurately. The diameter dependence of the sputtering shows a maximum if the ion range matches the nanowire diameter, which is in good agreement with Monte Carlo simulations based on binary collisions. Nanowires irradiated at room temperature, however, amorphize and deform plastically. So far, plastic deformation has not been observed in bulk silicon at such low ion energies. The magnitude and direction of the deformation is independent of the ion-beam direction and cannot be explained with mass-transport in a binary collision cascade but only by collective movement of atoms in the collision cascade with the given boundary conditions of a high surface to volume ratio. PMID:25951108

  5. Generation of correlated photons in nanoscale silicon waveguides

    NASA Astrophysics Data System (ADS)

    Sharping, Jay E.; Lee, Kim F.; Foster, Mark A.; Turner, Amy C.; Schmidt, Bradley S.; Lipson, Michal; Gaeta, Alexander L.; Kumar, Prem

    2006-12-01

    .We experimentally study the generation of correlated pairs of photons through four-wave mixing (FWM) in embedded silicon waveguides. The waveguides, which are designed to exhibit anomalous group-velocity dispersion at wavelengths near 1555 nm, allow phase matched FWM and thus efficient pair-wise generation of non-degenerate signal and idler photons. Photon counting measurements yield a coincidence-to-accidental ratio (CAR) of around 25 for a signal (idler) photon production rate of about 0.05 per pulse. We characterize the variation in CAR as a function of pump power and pump-to-sideband wavelength detuning. These measurements represent a first step towards the development of tools for quantum information processing which are based on CMOS-compatible, silicon-on-insulator technology.

  6. Anomalous Plastic Deformation and Sputtering of Ion Irradiated Silicon Nanowires.

    PubMed

    Johannes, Andreas; Noack, Stefan; Wesch, Werner; Glaser, Markus; Lugstein, Alois; Ronning, Carsten

    2015-06-10

    Silicon nanowires of various diameters were irradiated with 100 keV and 300 keV Ar(+) ions on a rotatable and heatable stage. Irradiation at elevated temperatures above 300 °C retains the geometry of the nanostructure and sputtering can be gauged accurately. The diameter dependence of the sputtering shows a maximum if the ion range matches the nanowire diameter, which is in good agreement with Monte Carlo simulations based on binary collisions. Nanowires irradiated at room temperature, however, amorphize and deform plastically. So far, plastic deformation has not been observed in bulk silicon at such low ion energies. The magnitude and direction of the deformation is independent of the ion-beam direction and cannot be explained with mass-transport in a binary collision cascade but only by collective movement of atoms in the collision cascade with the given boundary conditions of a high surface to volume ratio.

  7. Hybrid-Based Dense Stereo Matching

    NASA Astrophysics Data System (ADS)

    Chuang, T. Y.; Ting, H. W.; Jaw, J. J.

    2016-06-01

    Stereo matching generating accurate and dense disparity maps is an indispensable technique for 3D exploitation of imagery in the fields of Computer vision and Photogrammetry. Although numerous solutions and advances have been proposed in the literature, occlusions, disparity discontinuities, sparse texture, image distortion, and illumination changes still lead to problematic issues and await better treatment. In this paper, a hybrid-based method based on semi-global matching is presented to tackle the challenges on dense stereo matching. To ease the sensitiveness of SGM cost aggregation towards penalty parameters, a formal way to provide proper penalty estimates is proposed. To this end, the study manipulates a shape-adaptive cross-based matching with an edge constraint to generate an initial disparity map for penalty estimation. Image edges, indicating the potential locations of occlusions as well as disparity discontinuities, are approved by the edge drawing algorithm to ensure the local support regions not to cover significant disparity changes. Besides, an additional penalty parameter 𝑃𝑒 is imposed onto the energy function of SGM cost aggregation to specifically handle edge pixels. Furthermore, the final disparities of edge pixels are found by weighting both values derived from the SGM cost aggregation and the U-SURF matching, providing more reliable estimates at disparity discontinuity areas. Evaluations on Middlebury stereo benchmarks demonstrate satisfactory performance and reveal the potency of the hybrid-based dense stereo matching method.

  8. Temperature matching of multilayer insulation to penetrations

    NASA Astrophysics Data System (ADS)

    Johnson, W. L.; Plachta, D. W.; Rhys, N. O.; Kelly, A. O.

    2014-01-01

    To accurately predict the heat load into a cryogenic tank or cold mass which includes multilayer insulation (MLI), heat loads other than just through the pristine MLI must be accounted for. One such type of heat load is the integration of the MLI system around penetrations. While a number of different methods that have been developed, the ideal solution would be one in which there are zero thermal losses due to the integration. Theoretically, the be st method to achieving zero integration losses is to match the individual MLI temperature layers with the corresponding penetration location having the same temperature; this method is known as temperature matching. Recently, NASA has employed temperature matching integration of multilayer insulation systems onto several different cryogenic tanks with different structural elements and attachments. T esting included the Methane Lunar Surface Thermal Control testing at Glenn Research Center, the CRYOTE Ground Test Article testing at Marshall Space Flight Center, and the Penetration Calorimetery work done at Kennedy Space Center. Each test was instrumented to determine the effects of temperature matching within MLI and each system was designed in a different manner. The testing showed that temperature matching can indeed produce nearly zero thermal losses. However, our findings show that there are many practical limitations to this approach. Temperature matching integration schemes were found to be very sensitive to thermal environmental changes and even tank liquid level changes. The approach is therefore considered useful only for a select few cases and not useful for most engineering applications.

  9. Impedance matching vertical optical waveguide couplers for dense high index contrast circuits.

    PubMed

    Sun, Rong; Beals, Mark; Pomerene, Andrew; Cheng, Jing; Hong, Ching-Yin; Kimerling, Lionel; Michel, Jurgen

    2008-08-04

    We designed and demonstrated a compact, high-index contrast (HIC) vertical waveguide coupler for TE single mode operation with the lowest coupling loss of 0.20 dB +/- 0.05 dB at 1550 nm. Our vertical coupler consists of a pair of vertically overlapping inverse taper structures made of SOI and amorphous silicon. The vertical coupler can suppress power oscillation observed in regular directional couplers and guarantees vertical optical impedance matching with great tolerance for fabrication and refractive index variations of the waveguide materials. The coupler furthermore shows excellent broadband coupling efficiencies between 1460 nm and 1570 nm.

  10. SILICON AND BONE HEALTH

    PubMed Central

    JUGDAOHSINGH, R.

    2009-01-01

    Low bone mass (osteoporosis) is a silent epidemic of the 21st century, which presently in the UK results in over 200,000 fractures annually at a cost of over one billion pounds. Figures are set to increase worldwide. Understanding the factors which affect bone metabolism is thus of primary importance in order to establish preventative measures or treatments for this condition. Nutrition is an important determinant of bone health, but the effects of the individual nutrients and minerals, other than calcium, is little understood. Accumulating evidence over the last 30 years strongly suggest that dietary silicon is beneficial to bone and connective tissue health and we recently reported strong positive associations between dietary Si intake and bone mineral density in US and UK cohorts. The exact biological role(s) of silicon in bone health is still not clear, although a number of possible mechanisms have been suggested, including the synthesis of collagen and/or its stabilization, and matrix mineralization. This review gives an overview of this naturally occurring dietary element, its metabolism and the evidence of its potential role in bone health. PMID:17435952

  11. Micromachined silicon seismic transducers

    SciTech Connect

    Barron, C.C.; Fleming, J.G.; Sniegowski, J.J.; Armour, D.L.; Fleming, R.P.

    1995-08-01

    Batch-fabricated silicon seismic transducers could revolutionize the discipline of CTBT monitoring by providing inexpensive, easily depolyable sensor arrays. Although our goal is to fabricate seismic sensors that provide the same performance level as the current state-of-the-art ``macro`` systems, if necessary one could deploy a larger number of these small sensors at closer proximity to the location being monitored in order to compensate for lower performance. We have chosen a modified pendulum design and are manufacturing prototypes in two different silicon micromachining fabrication technologies. The first set of prototypes, fabricated in our advanced surface- micromachining technology, are currently being packaged for testing in servo circuits -- we anticipate that these devices, which have masses in the 1--10 {mu}g range, will resolve sub-mG signals. Concurrently, we are developing a novel ``mold`` micromachining technology that promises to make proof masses in the 1--10 mg range possible -- our calculations indicate that devices made in this new technology will resolve down to at least sub-{mu}G signals, and may even approach to 10{sup {minus}10} G/{radical}Hz acceleration levels found in the low-earth-noise model.

  12. Silicon production process evaluations

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Chemical engineering analysis was continued for the HSC process (Hemlock Semiconductor Corporation) in which solar cell silicon is produced in a 1,000 MT/yr plant. Progress and status are reported for the primary engineering activities involved in the preliminary process engineering design of the plant base case conditions (96%), reaction chemistry (96%), process flow diagram (85%), material balance (85%), energy balance (60%), property data (60%), equipment design (40%), major equipment list (30%) and labor requirements (10%). Engineering design of the second distillation column (D-02, TCS column) in the process was completed. The design is based on a 97% recovery of the light key (TCS, trichlorosilane) in the distillate and a 97% recovery of the heavy key (TET, silicon tetrachloride) in the bottoms. At a reflux ratio of 2, the specified recovery of TCS and TET is achieved with 20 trays (equilibrium stages, N=20). Respective feed tray locations are 9, 12 and 15 (NF sub 1 = 9, NF sub 2 = 12,, and NF sub 3 = 15). A total condenser is used for the distillation which is conducted at a pressure of 90 psia.

  13. Silicon and bone health.

    PubMed

    Jugdaohsingh, R

    2007-01-01

    Low bone mass (osteoporosis) is a silent epidemic of the 21st century, which presently in the UK results in over 200,000 fractures annually at a cost of over one billion pounds. Figures are set to increase worldwide. Understanding the factors which affect bone metabolism is thus of primary importance in order to establish preventative measures or treatments for this condition. Nutrition is an important determinant of bone health, but the effects of the individual nutrients and minerals, other than calcium, is little understood. Accumulating evidence over the last 30 years strongly suggest that dietary silicon is beneficial to bone and connective tissue health and we recently reported strong positive associations between dietary Si intake and bone mineral density in US and UK cohorts. The exact biological role(s) of silicon in bone health is still not clear, although a number of possible mechanisms have been suggested, including the synthesis of collagen and/or its stabilization, and matrix mineralization. This review gives an overview of this naturally occurring dietary element, its metabolism and the evidence of its potential role in bone health.

  14. Crystalline silicon growth in nickel/a-silicon bilayer

    SciTech Connect

    Mohiddon, Md Ahamad; Naidu, K. Lakshun; Dalba, G.; Rocca, F.; Krishna, M. Ghanashyam

    2013-02-05

    The effect of substrate temperature on amorphous Silicon crystallization, mediated by metal impurity is reported. Bilayers of Ni(200nm)/Si(400nm) are deposited on fused silica substrate by electron beam evaporator at 200 and 500 Degree-Sign C. Raman mapping shows that, 2 to 5 micron size crystalline silicon clusters are distributed over the entire surface of the sample. X-ray diffraction and X-ray absorption spectroscopy studies demonstrate silicon crystallizes over the metal silicide seeds and grow with the annealing temperature.

  15. Develop Silicone Encapsulation Systems for Terrestrial Silicon Solar Arrays

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The results of a study for Task 3 of the Low Cost Solar Array Project, directed toward the development of a cost effective encapsulation system for photovoltaic modules using silicon based materials, are reported. Results of the following are discussed: (1) weather-ometer stressing vs. weathering history of silicon and silicon modified materials; (2) humidity/temperature cycling exposure; (3) exposure at high humidity/high temperature; (4) outdoor exposure stress; (5) thermal cycling stress; and (6) UV screening agents. The plans for the next quarter are outlined.

  16. On the refractive index of sodium iodide solutions for index matching in PIV

    NASA Astrophysics Data System (ADS)

    Bai, Kunlun; Katz, Joseph

    2014-04-01

    Refractive index matching has become a popular technique for facilitating applications of modern optical diagnostic techniques, such as particle image velocimetry, in complex systems. By matching the refractive index of solid boundaries with that of the liquid, unobstructed optical paths can be achieved for illumination and image acquisition. In this research note, we extend previously provided data for the refractive index of aqueous solutions of sodium iodide (NaI) for concentrations reaching the temperature-dependent solubility limit. Results are fitted onto a quadratic empirical expression relating the concentration to the refractive index. Temperature effects are also measured. The present range of indices, 1.333-1.51, covers that of typical transparent solids, from silicone elastomers to several recently introduced materials that could be manufactured using rapid prototyping. We also review briefly previous measurements of the refractive index, viscosity, and density of NaI solutions, as well as prior research that has utilized this fluid.

  17. Silicon-doped boron nitride coated fibers in silicon melt infiltrated composites

    DOEpatents

    Corman, Gregory Scot; Luthra, Krishan Lal

    2002-01-01

    A fiber-reinforced silicon-silicon carbide matrix composite having improved oxidation resistance at high temperatures in dry or water-containing environments is produced. The invention also provides a method for protecting the reinforcing fibers in the silicon-silicon carbide matrix composites by coating the fibers with a silicon-doped boron nitride coating.

  18. Silicon-doped boron nitride coated fibers in silicon melt infiltrated composites

    DOEpatents

    Corman, Gregory Scot; Luthra, Krishan Lal

    1999-01-01

    A fiber-reinforced silicon--silicon carbide matrix composite having improved oxidation resistance at high temperatures in dry or water-containing environments is produced. The invention also provides a method for protecting the reinforcing fibers in the silicon--silicon carbide matrix composites by coating the fibers with a silicon-doped boron nitride coating.

  19. Silicon nitride/silicon carbide composite densified materials prepared using composite powders

    DOEpatents

    Dunmead, S.D.; Weimer, A.W.; Carroll, D.F.; Eisman, G.A.; Cochran, G.A.; Susnitzky, D.W.; Beaman, D.R.; Nilsen, K.J.

    1997-07-01

    Prepare silicon nitride-silicon carbide composite powders by carbothermal reduction of crystalline silica powder, carbon powder and, optionally, crystalline silicon nitride powder. The crystalline silicon carbide portion of the composite powders has a mean number diameter less than about 700 nanometers and contains nitrogen. The composite powders may be used to prepare sintered ceramic bodies and self-reinforced silicon nitride ceramic bodies.

  20. Privacy-preserving matching of similar patients.

    PubMed

    Vatsalan, Dinusha; Christen, Peter

    2016-02-01

    The identification of similar entities represented by records in different databases has drawn considerable attention in many application areas, including in the health domain. One important type of entity matching application that is vital for quality healthcare analytics is the identification of similar patients, known as similar patient matching. A key component of identifying similar records is the calculation of similarity of the values in attributes (fields) between these records. Due to increasing privacy and confidentiality concerns, using the actual attribute values of patient records to identify similar records across different organizations is becoming non-trivial because the attributes in such records often contain highly sensitive information such as personal and medical details of patients. Therefore, the matching needs to be based on masked (encoded) values while being effective and efficient to allow matching of large databases. Bloom filter encoding has widely been used as an efficient masking technique for privacy-preserving matching of string and categorical values. However, no work on Bloom filter-based masking of numerical data, such as integer (e.g. age), floating point (e.g. body mass index), and modulus (numbers wrap around upon reaching a certain value, e.g. date and time), which are commonly required in the health domain, has been presented in the literature. We propose a framework with novel methods for masking numerical data using Bloom filters, thereby facilitating the calculation of similarities between records. We conduct an empirical study on publicly available real-world datasets which shows that our framework provides efficient masking and achieves similar matching accuracy compared to the matching of actual unencoded patient records.

  1. A graph theoretic approach to scene matching

    NASA Technical Reports Server (NTRS)

    Ranganath, Heggere S.; Chipman, Laure J.

    1991-01-01

    The ability to match two scenes is a fundamental requirement in a variety of computer vision tasks. A graph theoretic approach to inexact scene matching is presented which is useful in dealing with problems due to imperfect image segmentation. A scene is described by a set of graphs, with nodes representing objects and arcs representing relationships between objects. Each node has a set of values representing the relations between pairs of objects, such as angle, adjacency, or distance. With this method of scene representation, the task in scene matching is to match two sets of graphs. Because of segmentation errors, variations in camera angle, illumination, and other conditions, an exact match between the sets of observed and stored graphs is usually not possible. In the developed approach, the problem is represented as an association graph, in which each node represents a possible mapping of an observed region to a stored object, and each arc represents the compatibility of two mappings. Nodes and arcs have weights indicating the merit or a region-object mapping and the degree of compatibility between two mappings. A match between the two graphs corresponds to a clique, or fully connected subgraph, in the association graph. The task is to find the clique that represents the best match. Fuzzy relaxation is used to update the node weights using the contextual information contained in the arcs and neighboring nodes. This simplifies the evaluation of cliques. A method of handling oversegmentation and undersegmentation problems is also presented. The approach is tested with a set of realistic images which exhibit many types of sementation errors.

  2. Silicene: silicon conquers the 2D world

    NASA Astrophysics Data System (ADS)

    Le Lay, Guy; Salomon, Eric; Angot, Thierry

    2016-01-01

    We live in the digital age based on the silicon chip and driven by Moore's law. Last July, IBM created a surprise by announcing the fabrication of a 7 nm test chip with functional transistors using, instead of just silicon, a silicon-germanium alloy. Will silicon be dethroned?

  3. PREPARATION AND PURIFICATION OF SILICON CARBIDE.

    DTIC Science & Technology

    the materials were divided into two parts. Part I covers problems of silicon carbide preparation and the growing of silicon carbide single crystals...and thin films for semiconductor devices. Part II treats problems of purity, including the purification and chemical analysis of silicon carbide and of starting materials for silicon carbide preparation.

  4. Ceramic for Silicon-Shaping Dies

    NASA Technical Reports Server (NTRS)

    Sekercioglu, I.; Wills, R. R.

    1982-01-01

    Silicon beryllium oxynitride (SiBON) is a promising candidate material for manufacture of shaping dies used in fabricating ribbons or sheets of silicon. It is extremely stable, resists thermal shock, and has excellent resistance to molten silicon. SiBON is a solid solution of beryllium silicate in beta-silicon nitride.

  5. Oxide Control for Silicon Crystal Growth

    NASA Technical Reports Server (NTRS)

    Wehrli, H. A. I.

    1982-01-01

    Web dendrite growth process pulls sheet of newly crystallized silicon from molten silicon. Jets of argon pull outside gas into melt cavity, preventing silicon oxide from passing through heat-shield hold and depositing on it. Generated by aspirators, reversed flow is used in web dendrite process, which produces sheets of single-crystal silicon for low-cost solar cells.

  6. Determination of Silicon in Hydrazine

    NASA Technical Reports Server (NTRS)

    McClure, Mark B.; Mast, Dion; Greene, Ben; Maes, Miguel J.

    2006-01-01

    Inductively coupled plasma-mass spectrometry (ICP-MS) is a highly sensitive technique sometimes used for the trace determination of silicon at a mass-to-charge (m/z) ratio of 28, the most abundant natural isotope of silicon. Unfortunately, ICP-MS is unable to differentiate between other sources of m/z 28 and false positive results for silicon will result when other sources of m/z 28 are present. Nitrogen was a major source of m/z 28 and contributes to the m/z 28 signal when hydrazine sample or nitric acid preservative is introduced into the plasma. Accordingly, this work was performed to develop a sample preparation step coupled with an ICP-MS analysis that minimized non-silicon sources of m/z 28. In the preparatory step of this method, the hydrazine sample was first decomposed predominately to nitrogen gas and water with copper-catalyzed hydrogen peroxide. In the analysis step, ICP-MS was used without nitric acid preservative in samples or standards. Glass, a potential source of silicon contamination, was also avoided where possible. The method was sensitive, accurate, and reliable for the determination of silicon in monopropellant grade hydrazine (MPH) in AF-E-332 elastomer leaching tests. Results for silicon in MPH were comparable to those reported in the literature for other studies.

  7. High specific activity silicon-32

    DOEpatents

    Phillips, Dennis R.; Brzezinski, Mark A.

    1996-01-01

    A process for preparation of silicon-32 is provided and includes contacting an irradiated potassium chloride target, including spallation products from a prior irradiation, with sufficient water, hydrochloric acid or potassium hydroxide to form a solution, filtering the solution, adjusting pH of the solution to from about 5.5 to about 7.5, admixing sufficient molybdate-reagent to the solution to adjust the pH of the solution to about 1.5 and to form a silicon-molybdate complex, contacting the solution including the silicon-molybdate complex with a dextran-based material, washing the dextran-based material to remove residual contaminants such as sodium-22, separating the silicon-molybdate complex from the dextran-based material as another solution, adding sufficient hydrochloric acid and hydrogen peroxide to the solution to prevent reformation of the silicon-molybdate complex and to yield an oxidization state of the molybdate adapted for subsequent separation by an anion exchange material, contacting the solution with an anion exchange material whereby the molybdate is retained by the anion exchange material and the silicon remains in solution, and optionally adding sufficient alkali metal hydroxide to adjust the pH of the solution to about 12 to 13. Additionally, a high specific activity silicon-32 product having a high purity is provided.

  8. High specific activity silicon-32

    DOEpatents

    Phillips, D.R.; Brzezinski, M.A.

    1996-06-11

    A process for preparation of silicon-32 is provided and includes contacting an irradiated potassium chloride target, including spallation products from a prior irradiation, with sufficient water, hydrochloric acid or potassium hydroxide to form a solution, filtering the solution, adjusting pH of the solution from about 5.5 to about 7.5, admixing sufficient molybdate-reagent to the solution to adjust the pH of the solution to about 1.5 and to form a silicon-molybdate complex, contacting the solution including the silicon-molybdate complex with a dextran-based material, washing the dextran-based material to remove residual contaminants such as sodium-22, separating the silicon-molybdate complex from the dextran-based material as another solution, adding sufficient hydrochloric acid and hydrogen peroxide to the solution to prevent reformation of the silicon-molybdate complex and to yield an oxidation state of the molybdate adapted for subsequent separation by an anion exchange material, contacting the solution with an anion exchange material whereby the molybdate is retained by the anion exchange material and the silicon remains in solution, and optionally adding sufficient alkali metal hydroxide to adjust the pH of the solution to about 12 to 13. Additionally, a high specific activity silicon-32 product having a high purity is provided.

  9. Process for forming retrograde profiles in silicon

    DOEpatents

    Weiner, K.H.; Sigmon, T.W.

    1996-10-15

    A process is disclosed for forming retrograde and oscillatory profiles in crystalline and polycrystalline silicon. The process consisting of introducing an n- or p-type dopant into the silicon, or using prior doped silicon, then exposing the silicon to multiple pulses of a high-intensity laser or other appropriate energy source that melts the silicon for short time duration. Depending on the number of laser pulses directed at the silicon, retrograde profiles with peak/surface dopant concentrations which vary are produced. The laser treatment can be performed in air or in vacuum, with the silicon at room temperature or heated to a selected temperature.

  10. Process for forming retrograde profiles in silicon

    DOEpatents

    Weiner, Kurt H.; Sigmon, Thomas W.

    1996-01-01

    A process for forming retrograde and oscillatory profiles in crystalline and polycrystalline silicon. The process consisting of introducing an n- or p-type dopant into the silicon, or using prior doped silicon, then exposing the silicon to multiple pulses of a high-intensity laser or other appropriate energy source that melts the silicon for short time duration. Depending on the number of laser pulses directed at the silicon, retrograde profiles with peak/surface dopant concentrations which vary from 1-1e4 are produced. The laser treatment can be performed in air or in vacuum, with the silicon at room temperature or heated to a selected temperature.

  11. Silicon Nanowire Photocathodes for Photoelectrochemical Hydrogen Production

    PubMed Central

    Chandrasekaran, Soundarrajan; Nann, Thomas; Voelcker, Nicolas H.

    2016-01-01

    The performance of silicon for water oxidation and hydrogen production can be improved by exploiting the antireflective properties of nanostructured silicon substrates. In this work, silicon nanowires were fabricated by metal-assisted electroless etching of silicon. An enhanced photocurrent density of −17 mA/cm2 was observed for the silicon nanowires coated with an iron sulphur carbonyl catalyst when compared to bare silicon nanowires (−5 mA/cm2). A substantial amount of 315 µmol/h hydrogen gas was produced at low bias potentials for the silicon nanowires coated with an iron sulphur carbonyl catalyst. PMID:28335272

  12. Formation of dielectric silicon compounds by reactive magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Veselov, D. S.; Voronov, Yu A.

    2016-09-01

    The paper is devoted to the study of reactive magnetron sputtering of the silicon target in the ambient of inert argon gas with reactive gas, nitrogen or oxygen. The magnetron was powered by two mid-frequency generators of a rectangular pulse of opposite polarity. The negative polarity pulse provides the sputtering of the target. The positive polarity pulse provides removal of accumulated charge from the surface of the target. This method does not require any special devices of resistances matching and provides continuous sputtering of the target.

  13. A liquid regime equation of state for silicon dioxide

    NASA Astrophysics Data System (ADS)

    Sjostrom, Travis; Crockett, Scott

    2015-06-01

    A new SESAME liquid phase silicon dioxide equation of state (EOS) has been developed utilizing the best experimental data and theoretical calculations. The EOS inputs include recent alpha-quartz shock Hugoniot results from the Sandia Z machine experiments, as well as quantum molecular dynamics simulations. An immediate and critical application of the new EOS lies in analysis of shock experiments where in recent years alpha-quartz has been used extensively as an impedance match standard at significant (above ~100 Gpa) pressures to measure shock velocities.

  14. Replacement of silicone polymer A with silicone polymer B and the subsequent characterization of the new cellular silicone materials

    SciTech Connect

    Schneider, J.W.

    1994-04-01

    The purpose of this project is to replace silicone polymer A with silicone polymer B produced by Vendor B. Silicone polymer B and the resulting B-50 cellular silicone have been used to produce cushions for the W87 program. Approximately 5.5 years of stress relaxation aging study data as well as actual part surveillance data have been collected, characterizing the stockpile life performance of the B-50 cellular silicone cushion material. Process characterization of new cellular silicone materials as a result of replacing silicone polymer A with silicone polymer B has been completed. Load deflection requirements for the new cellular silicone materials based on silicone polymer B have been met. The silicone polymer B based cellular silicone materials must be compounded at densities of approximately 0.03 g/cm{sup 3} less than the silicone polymer A based cellular silicone materials in order to achieve the same load deflection requirements has also been demonstrated. The change in silicone polymers from A to B involved a decrease in volatile content as well as a decrease in part shrinkage.

  15. Fabrication and characterization of porous silicon nanowires

    NASA Astrophysics Data System (ADS)

    Jung, Daeyoon; Cho, Soo Gyeong; Moon, Taeho; Sohn, Honglae

    2016-01-01

    We report the synthesis of porous silicon nanowires through the metalassisted chemical etching of porous silicon in a solution of hydrofluoric acid and hydrogen peroxide. The morphology of porous silicon nanowires was characterized by scanning electron microscopy and transmission electron microscopy. The etch rate of the porous silicon nanowires was faster than that of silicon nanowires, but slower than that of porous silicon. The porous silicon nanowires distributed uniformly on the entire porous silicon layer and the tips of the porous silicon nanowires congregated together. The single crystalline and sponge-like porous structure with the pore diameters of less than 5 nm was confirmed for the porous silicon nanowires. [Figure not available: see fulltext.

  16. 75 FR 28252 - Notice of a Computer Matching Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-20

    ... ADMINISTRATION Notice of a Computer Matching Program AGENCY: General Services Administration ACTION: Notice... proposed computer match. The purpose of this match is to identify individuals who are improperly receiving... notice of a proposed computer match. The purpose of this match is to identify individuals who...

  17. 11 CFR 9032.5 - Matching payment account.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... MATCHING FUND DEFINITIONS § 9032.5 Matching payment account. Matching payment account means the Presidential Primary Matching Payment Account established by the Secretary of the Treasury under 26 U.S.C. 9037... 11 Federal Elections 1 2010-01-01 2010-01-01 false Matching payment account. 9032.5 Section...

  18. Feature matching algorithm based on spatial similarity

    NASA Astrophysics Data System (ADS)

    Tang, Wenjing; Hao, Yanling; Zhao, Yuxin; Li, Ning

    2008-10-01

    The disparities of features that represent the same real world entities from disparate sources usually occur, thus the identification or matching of features is crutial to the map conflation. Motivated by the idea of identifying the same entities through integrating known information by eyes, the feature matching algorithm based on spatial similarity is proposed in this paper. Total similarity is obtained by integrating positional similarity, shape similarity and size similarity with a weighted average algorithm, then the matching entities is achieved according to the maximum total similarity. The matching of areal features is analyzed in detail. Regarding the areal feature as a whole, the proposed algorithm identifies the same areal features by their shape-center points in order to calculate their positional similarity, and shape similarity is given by the function of describing the shape, which ensures its precision not be affected by interferes and avoids the loss of shape information, furthermore the size of areal features is measured by their covered areas. Test results show the stability and reliability of the proposed algorithm, and its precision and recall are higher than other matching algorithm.

  19. Antenna impedance matching with neural networks.

    PubMed

    Hemminger, Thomas L

    2005-10-01

    Impedance matching between transmission lines and antennas is an important and fundamental concept in electromagnetic theory. One definition of antenna impedance is the resistance and reactance seen at the antenna terminals or the ratio of electric to magnetic fields at the input. The primary intent of this paper is real-time compensation for changes in the driving point impedance of an antenna due to frequency deviations. In general, the driving point impedance of an antenna or antenna array is computed by numerical methods such as the method of moments or similar techniques. Some configurations do lend themselves to analytical solutions, which will be the primary focus of this work. This paper employs a neural control system to match antenna feed lines to two common antennas during frequency sweeps. In practice, impedance matching is performed off-line with Smith charts or relatively complex formulas but they rarely perform optimally over a large bandwidth. There have been very few attempts to compensate for matching errors while the transmission system is in operation and most techniques have been targeted to a relatively small range of frequencies. The approach proposed here employs three small neural networks to perform real-time impedance matching over a broad range of frequencies during transmitter operation. Double stub tuners are being explored in this paper but the approach can certainly be applied to other methodologies. The ultimate purpose of this work is the development of an inexpensive microcontroller-based system.

  20. Iris Matching Based on Personalized Weight Map.

    PubMed

    Dong, Wenbo; Sun, Zhenan; Tan, Tieniu

    2011-09-01

    Iris recognition typically involves three steps, namely, iris image preprocessing, feature extraction, and feature matching. The first two steps of iris recognition have been well studied, but the last step is less addressed. Each human iris has its unique visual pattern and local image features also vary from region to region, which leads to significant differences in robustness and distinctiveness among the feature codes derived from different iris regions. However, most state-of-the-art iris recognition methods use a uniform matching strategy, where features extracted from different regions of the same person or the same region for different individuals are considered to be equally important. This paper proposes a personalized iris matching strategy using a class-specific weight map learned from the training images of the same iris class. The weight map can be updated online during the iris recognition procedure when the successfully recognized iris images are regarded as the new training data. The weight map reflects the robustness of an encoding algorithm on different iris regions by assigning an appropriate weight to each feature code for iris matching. Such a weight map trained by sufficient iris templates is convergent and robust against various noise. Extensive and comprehensive experiments demonstrate that the proposed personalized iris matching strategy achieves much better iris recognition performance than uniform strategies, especially for poor quality iris images.

  1. Sketch Matching on Topology Product Graph.

    PubMed

    Liang, Shuang; Luo, Jun; Liu, Wenyin; Wei, Yichen

    2015-08-01

    Sketch matching is the fundamental problem in sketch based interfaces. After years of study, it remains challenging when there exists large irregularity and variations in the hand drawn sketch shapes. While most existing works exploit topology relations and graph representations for this problem, they are usually limited by the coarse topology exploration and heuristic (thus suboptimal) similarity metrics between graphs. We present a new sketch matching method with two novel contributions. We introduce a comprehensive definition of topology relations, which results in a rich and informative graph representation of sketches. For graph matching, we propose topology product graph that retains the full correspondence for matching two graphs. Based on it, we derive an intuitive sketch similarity metric whose exact solution is easy to compute. In addition, the graph representation and new metric naturally support partial matching, an important practical problem that received less attention in the literature. Extensive experimental results on a real challenging dataset and the superior performance of our method show that it outperforms the state-of-the-art.

  2. Matched filter based iterative adaptive approach

    NASA Astrophysics Data System (ADS)

    Nepal, Ramesh; Zhang, Yan Rockee; Li, Zhengzheng; Blake, William

    2016-05-01

    Matched Filter sidelobes from diversified LPI waveform design and sensor resolution are two important considerations in radars and active sensors in general. Matched Filter sidelobes can potentially mask weaker targets, and low sensor resolution not only causes a high margin of error but also limits sensing in target-rich environment/ sector. The improvement in those factors, in part, concern with the transmitted waveform and consequently pulse compression techniques. An adaptive pulse compression algorithm is hence desired that can mitigate the aforementioned limitations. A new Matched Filter based Iterative Adaptive Approach, MF-IAA, as an extension to traditional Iterative Adaptive Approach, IAA, has been developed. MF-IAA takes its input as the Matched Filter output. The motivation here is to facilitate implementation of Iterative Adaptive Approach without disrupting the processing chain of traditional Matched Filter. Similar to IAA, MF-IAA is a user parameter free, iterative, weighted least square based spectral identification algorithm. This work focuses on the implementation of MF-IAA. The feasibility of MF-IAA is studied using a realistic airborne radar simulator as well as actual measured airborne radar data. The performance of MF-IAA is measured with different test waveforms, and different Signal-to-Noise (SNR) levels. In addition, Range-Doppler super-resolution using MF-IAA is investigated. Sidelobe reduction as well as super-resolution enhancement is validated. The robustness of MF-IAA with respect to different LPI waveforms and SNR levels is also demonstrated.

  3. Optimally matching support and perceived spousal sensitivity.

    PubMed

    Cutrona, Carolyn E; Shaffer, Philip A; Wesner, Kristin A; Gardner, Kelli A

    2007-12-01

    Partner sensitivity is an important antecedent of both intimacy (H. T. Reis & P. Shaver, 1988) and attachment (M. D. S. Ainsworth, 1989). On the basis of the optimal matching model of social support (C. E. Cutrona & D. Russell, 1990), support behaviors that "matched" the support goals of the stressed individual were predicted to lead to the perception of partner sensitivity. Predictions were tested with 59 married couples, who engaged in a videotaped self-disclosure task. Matching support was defined as the disclosure of emotions followed by emotional support or a request for information followed by informational support. Partial evidence was found for the predictions. Matching support following the disclosure of emotions was predictive of perceived partner sensitivity. Mismatched support following the disclosure of emotions predicted lower marital satisfaction, through the mediation of partner sensitivity. Matching support following a request for information was not predictive of perceived partner sensitivity, but negative partner responses (e.g., criticism or sarcasm) following a request for information negatively predicted perceptions of partner sensitivity. The importance of considering the context of support transactions is discussed.

  4. Single crystalline mesoporous silicon nanowires.

    PubMed

    Hochbaum, Allon I; Gargas, Daniel; Hwang, Yun Jeong; Yang, Peidong

    2009-10-01

    Herein we demonstrate a novel electroless etching synthesis of monolithic, single-crystalline, mesoporous silicon nanowire arrays with a high surface area and luminescent properties consistent with conventional porous silicon materials. These porous nanowires also retain the crystallographic orientation of the wafer from which they are etched. Electron microscopy and diffraction confirm their single-crystallinity and reveal the silicon surrounding the pores is as thin as several nanometers. Confocal fluorescence microscopy showed that the photoluminescence (PL) of these arrays emanate from the nanowires themselves, and their PL spectrum suggests that these arrays may be useful as photocatalytic substrates or active components of nanoscale optoelectronic devices.

  5. Single crystalline mesoporous silicon nanowires

    SciTech Connect

    Hochbaum, A.I.; Gargas, Daniel; Jeong Hwang, Yun; Yang, Peidong

    2009-08-04

    Herein we demonstrate a novel electroless etching synthesis of monolithic, single-crystalline, mesoporous silicon nanowire arrays with a high surface area and luminescent properties consistent with conventional porous silicon materials. These porous nanowires also retain the crystallographic orientation of the wafer from which they are etched. Electron microscopy and diffraction confirm their single-crystallinity and reveal the silicon surrounding the pores is as thin as several nanometers. Confocal fluorescence microscopy showed that the photoluminescence (PL) of these arrays emanate from the nanowires themselves, and their PL spectrum suggests that these arrays may be useful as photocatalytic substrates or active components of nanoscale optoelectronic devices.

  6. Ultra-fast silicon detectors

    NASA Astrophysics Data System (ADS)

    Sadrozinski, H. F.-W.; Ely, S.; Fadeyev, V.; Galloway, Z.; Ngo, J.; Parker, C.; Petersen, B.; Seiden, A.; Zatserklyaniy, A.; Cartiglia, N.; Marchetto, F.; Bruzzi, M.; Mori, R.; Scaringella, M.; Vinattieri, A.

    2013-12-01

    We propose to develop a fast, thin silicon sensor with gain capable to concurrently measure with high precision the space (∼10 μm) and time (∼10 ps) coordinates of a particle. This will open up new application of silicon detector systems in many fields. Our analysis of detector properties indicates that it is possible to improve the timing characteristics of silicon-based tracking sensors, which already have sufficient position resolution, to achieve four-dimensional high-precision measurements. The basic sensor characteristics and the expected performance are listed, the wide field of applications are mentioned and the required R&D topics are discussed.

  7. Develop Silicone Encapsulation Systems for Terrestrial Silicon Solar Arrays

    NASA Technical Reports Server (NTRS)

    1979-01-01

    A cost effective encapsulant system was identified and a silicone acrylic cover material containing a durable ultraviolet screening agent was prepared. The effectiveness of the cover material in protecting photo-oxidatively sensitive polymers was demonstrated.

  8. Micromechanical silicon precision scale

    NASA Astrophysics Data System (ADS)

    Oja, Aarne S.; Sillanpaa, Teuvo; Seppae, H.; Kiihamaki, Jyrki; Seppala, P.; Karttunen, Jani; Riski, Kari

    2000-04-01

    A micro machined capacitive silicon scale has been designed and fabricated. It is intended for weighing masses on the order of 1 g at the resolution of about 1 ppm and below. The device consists of a micro machined SOI chip which is anodically bonded to a glass chip. The flexible electrode is formed in the SOI device layer. The other electrode is metallized on the glass and is divided into three sections. The sections are used for detecting tilting of the top electrode due to a possible off-centering of the mass load. The measuring circuit implements electrostatic force feedback and keeps the top electrode at a constant horizontal position irrespective of its mass loading. First measurements have demonstrated the stability allowing measurement of 1 g masses at an accuracy of 2...3 ppm.

  9. Silicon production process evaluations

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Chemical engineering analysis of the HSC process (Hemlock Semiconductor Corporation) for producing silicon from dichlorosilane in a 1,000 MT/yr plant was continued. Progress and status for the chemical engineering analysis of the HSC process are reported for the primary process design engineering activities: base case conditions (85%), reaction chemistry (85%), process flow diagram (60%), material balance (60%), energy balance (30%), property data (30%), equipment design (20%) and major equipment list (10%). Engineering design of the initial distillation column (D-01, stripper column) in the process was initiated. The function of the distillation column is to remove volatile gases (such as hydrogen and nitrogen) which are dissolved in liquid chlorosilanes. Initial specifications and results for the distillation column design are reported including the variation of tray requirements (equilibrium stages) with reflux ratio for the distillation.

  10. Silicon tracker data acquisition

    SciTech Connect

    Haynes, W.J.

    1997-12-31

    Large particle physics experiments are making increasing technological demands on the design and implementation of real-time data acquisition systems. The LHC will have bunch crossing intervals of 25 nanoseconds and detectors, such as CMS, will contain over 10 million electronic channels. Readout systems will need to cope with 100 kHz rates of 1 MByte-sized events. Over 70% of this voluminous flow will stem from silicon tracker and MSGC devices. This paper describes the techniques currently being harnessed from ASIC devices through to modular microprocessor-based architectures around standards such as VMEbus and PCI. In particular, the experiences gained at the HERA H1 experiment are highlighted where many of the key technological concepts have already been im implemented.

  11. The ISOLDE Silicon Ball

    SciTech Connect

    Fraile, L.M.

    2003-09-16

    The investigation of weakly bound nuclei close to the particle driplines makes necessary the development of new spectroscopy devices with the capability of detecting charged particles and precisely determining their energy, angular distribution and nature. With this aim the ISOLDE Silicon Ball is under construction. It is a charged particle spectroscopy device with the requirements of high geometrical efficiency and broad energy range coverage, designed for the investigation of the exotic nuclei produced at ISOLDE and at other similar facilities. In order to allow for particle identification the simultaneous use of the Time of Flight (TOF) and Pulse Shape Discrimination (PSD) techniques is intended. Recoil tagging capabilities, suitable for transfer reactions to be performed at REX-ISOLDE, should be foreseen for a future development. The design and realization of the first prototype, together with the first tests are reported.

  12. Crystallization of Silicon Ribbons

    NASA Technical Reports Server (NTRS)

    Leipold, M. H.

    1984-01-01

    Purity constraints for reasonable solar-cell efficiency require that silicon-ribbon growth for photovoltaics occur in a regime in which constitutional supercooling or other compositional effects on the crystallization front are not important. A major consideration in the fundamentals of crystallization is the removal of the latent heat of fusion. The direction of removal, compared with the growth direction, has a major influence on the crystallization rate and the development of localized stresses. The detailed shape of the crystallization front appears to have two forms: that required for dendritic-web growth, and that occurring in all others. After the removal of the latent heat of fusion, the thermal-mechanical behavior of all ribbons appears similar within the constraints of the exothermal gradient. The technological constraints in achieving the required thermal and mechanical conditions vary widely among the growth processes.

  13. Monolithic silicon bolometers

    NASA Technical Reports Server (NTRS)

    Downey, P. M.; Jeffries, A. D.; Meyer, S. S.; Weiss, R.; Bachner, F. J.; Donnelly, J. P.; Lindley, W. T.; Mountain, R. W.; Silversmith, D. J.

    1984-01-01

    A new type of bolometer detector for the millimeter and submillimeter spectral range is described. The bolometer is constructed of silicon using integrated circuit fabrication techniques. Ion implantation is used to give controlled resistance vs temperature properties as well as extremely low 1/f noise contacts. The devices have been tested between 4.2 and 0.3 K. The best electrical NEP measured is 4 x 10 to the -16th W/Hz to the 1/2 at 0.35 K between 1- and 10-Hz modulation frequency. This device had a detecting area of 0.25 sq cm and a time constant of 20 msec at a bath temperature of 0.35 K.

  14. Silicon force sensor

    DOEpatents

    Galambos, Paul C.; Crenshaw, Thomas B.; Nishida, Erik E.; Burnett, Damon J.; Lantz, Jeffrey W.

    2016-07-05

    The various technologies presented herein relate to a sensor for measurement of high forces and/or high load shock rate(s), whereby the sensor utilizes silicon as the sensing element. A plate of Si can have a thinned region formed therein on which can be formed a number of traces operating as a Wheatstone bridge. The brittle Si can be incorporated into a layered structure comprising ductile and/or compliant materials. The sensor can have a washer-like configuration which can be incorporated into a nut and bolt configuration, whereby tightening of the nut and bolt can facilitate application of a compressive preload upon the sensor. Upon application of an impact load on the bolt, the compressive load on the sensor can be reduced (e.g., moves towards zero-load), however the magnitude of the preload can be such that the load on the sensor does not translate to tensile stress being applied to the sensor.

  15. 78 FR 42080 - Privacy Act of 1974; CMS Computer Match No. 2013-07; HHS Computer Match No. 1303; DoD-DMDC Match...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-15

    ... HUMAN SERVICES Centers for Medicare & Medicaid Services Privacy Act of 1974; CMS Computer Match No. 2013-07; HHS Computer Match No. 1303; DoD-DMDC Match No. 18 AGENCY: Centers for Medicare & Medicaid Services (CMS), Department of Health and Human Services (HHS). ACTION: Notice of Computer Matching...

  16. Silicon Carbide Nanotube Synthesized

    NASA Technical Reports Server (NTRS)

    Lienhard, Michael A.; Larkin, David J.

    2003-01-01

    Carbon nanotubes (CNTs) have generated a great deal of scientific and commercial interest because of the countless envisioned applications that stem from their extraordinary materials properties. Included among these properties are high mechanical strength (tensile and modulus), high thermal conductivity, and electrical properties that make different forms of single-walled CNTs either conducting or semiconducting, and therefore, suitable for making ultraminiature, high-performance CNT-based electronics, sensors, and actuators. Among the limitations for CNTs is their inability to survive in high-temperature, harsh-environment applications. Silicon carbon nanotubes (SiCNTs) are being developed for their superior material properties under such conditions. For example, SiC is stable in regards to oxidation in air to temperatures exceeding 1000 C, whereas carbon-based materials are limited to 600 C. The high-temperature stability of SiCNTs is envisioned to enable high-temperature, harsh-environment nanofiber- and nanotube-reinforced ceramics. In addition, single-crystal SiC-based semiconductors are being developed for hightemperature, high-power electronics, and by analogy to CNTs with silicon semiconductors, SiCNTs with single-crystal SiC-based semiconductors may allow high-temperature harsh-environment nanoelectronics, nanosensors, and nanoactuators to be realized. Another challenge in CNT development is the difficulty of chemically modifying the tube walls, which are composed of chemically stable graphene sheets. The chemical substitution of the CNTs walls will be necessary for nanotube self-assembly and biological- and chemical-sensing applications. SiCNTs are expected to have a different multiple-bilayer wall structure, allowing the surface Si atoms to be functionalized readily with molecules that will allow SiCNTs to undergo self-assembly and be compatible with a variety of materials (for biotechnology applications and high-performance fiber-reinforced ceramics).

  17. Silicon Holder For Molecular-Beam Epitaxy

    NASA Technical Reports Server (NTRS)

    Hoenk, Michael E.; Grunthaner, Paula J.; Grunthaner, Frank J.

    1993-01-01

    Simple assembly of silicon wafers holds silicon-based charge-coupled device (CCD) during postprocessing in which silicon deposited by molecular-beam epitaxy. Attains temperatures similar to CCD, so hotspots suppressed. Coefficients of thermal expansion of holder and CCD equal, so thermal stresses caused by differential thermal expansion and contraction do not develop. Holder readily fabricated, by standard silicon processing techniques, to accommodate various CCD geometries. Silicon does not contaminate CCD or molecular-beam-epitaxy vacuum chamber.

  18. Integrated silicon and silicon nitride photonic circuits on flexible substrates.

    PubMed

    Chen, Yu; Li, Mo

    2014-06-15

    Flexible integrated photonic devices based on crystalline materials on plastic substrates have a promising potential in many unconventional applications. In this Letter, we demonstrate a fully integrated photonic system including ring resonators and grating couplers, based on both crystalline silicon and silicon nitride, on flexible plastic substrate by using the stamping-transfer method. A high yield has been achieved by a simple, yet reliable transfer method without significant performance degradation.

  19. Corrosion Characteristics of Silicon Carbide and Silicon Nitride

    PubMed Central

    Munro, R. G.; Dapkunas, S. J.

    1993-01-01

    The present work is a review of the substantial effort that has been made to measure and understand the effects of corrosion with respect to the properties, performance, and durability of various forms of silicon carbide and silicon nitride. The review encompasses corrosion in diverse environments, usually at temperatures of 1000 °C or higher. The environments include dry and moist oxygen, mixtures of hot gaseous vapors, molten salts, molten metals, and complex environments pertaining to coal ashes and slags. PMID:28053489

  20. Non-lattice matched metallic superlattices

    NASA Astrophysics Data System (ADS)

    Schuller, I. K.; Grimsditch, M.

    1987-03-01

    High quality multilayers can be grown by sputtering and molecular beam epitaxy techniques. If the constituents are not lattice matched and do not form solid solutions, the reasons for the growth into superlattices is not understood. For some limited cases (Mo/Ni, Nb/Cu, V/Ni, Ag/Co) high quality superlattices can be grown quite easily, although the in plane structure is polycrystalline. If the constituents form solid solutions and are lattice matched the growth into single crystalline superlattices is possible, although more interdiffusion is likely. The physical properties in nonlattice matched superlattices exhibit anomalous elastic constants and a metal-nonmetal transition in their normal state properties. By changing the relative coupling across a normal material we have observed dimensional crossover in superconducting superlattices and the development of magnon bands in magnetic superlattices.

  1. Rigid body constrained noisy point pattern matching.

    PubMed

    Morgera, S D; Cheong, P C

    1995-01-01

    Noisy pattern matching problems arise in many areas, e.g., computational vision, robotics, guidance and control, stereophotogrammetry, astronomy, genetics, and high-energy physics. Least-squares pattern matching over the Euclidean space E(n) for unordered sets of cardinalities p and q is commonly formulated as a combinatorial optimization problem having complexity p(p-1)...(p-q+1), q=/matching problem under rigid motion constraints, which often apply. The method reduces the complexity to l(21).n(4)+l(12).p(3), where l(12) and l(21) are the number of iterations required by steepest-ascent and singular value decomposition (SVD)-based procedures, respectively.

  2. Benchmarking Image Matching for Surface Description

    NASA Astrophysics Data System (ADS)

    Haala, Norbert; Stößel, Wolfgang; Gruber, Michael; Pfeifer, Norbert; Fritsch, Dieter

    2013-04-01

    Semi Global Matching algorithms have encompassed a renaissance to process stereoscopic data sets for surface reconstructions. This method is capable to provide very dense point clouds with sampling distances close to the Ground Sampling Resolution (GSD) of aerial images. EuroSDR, the pan-European organization of Spatial Data Research has initiated a benchmark for dense image matching. The expected outcomes of this benchmark are assessments for suitability, quality measures for dense surface reconstructions and run-time aspects. In particular, aerial image blocks of two sites covering two types of landscapes (urban and rural) are analysed. The benchmark' participants provide their results with respect to several criteria. As a follow-up an overall evaluation is given. Finally, point clouds of rural and urban surfaces delivered by very dense image matching algorithms and software packages are presented and results are compared.

  3. Patient Matching within a Health Information Exchange

    PubMed Central

    Godlove, Tim; Ball, Adrian W.

    2015-01-01

    The purpose of this article is to describe the patient matching problems resulting from the Nationwide Health Information Network's automated patient discovery specification and propose a more effective and secure approach for patient matching between health information organizations participating in a health information exchange. This proposed approach would allow the patient to match his or her identity between a health information organization's electronic health records (EHRs) at the same time the patient identifies which EHR data he or she consents to share between organizations. The patient's EHR username/password combination would be the credential used to establish and maintain health information exchange identity and consent data. The software developed to support this approach (e.g., an EHR health information exchange module) could also allow a patient to see what health information was shared when and with whom. PMID:26755901

  4. Patient Matching within a Health Information Exchange.

    PubMed

    Godlove, Tim; Ball, Adrian W

    2015-01-01

    The purpose of this article is to describe the patient matching problems resulting from the Nationwide Health Information Network's automated patient discovery specification and propose a more effective and secure approach for patient matching between health information organizations participating in a health information exchange. This proposed approach would allow the patient to match his or her identity between a health information organization's electronic health records (EHRs) at the same time the patient identifies which EHR data he or she consents to share between organizations. The patient's EHR username/password combination would be the credential used to establish and maintain health information exchange identity and consent data. The software developed to support this approach (e.g., an EHR health information exchange module) could also allow a patient to see what health information was shared when and with whom.

  5. Optimal Affine-Invariant Point Matching

    NASA Astrophysics Data System (ADS)

    Costa, Mauro S.; Haralick, Robert M.; Phillips, Tsaiyun I.; Shapiro, Linda G.

    1989-03-01

    The affine-transformation matching scheme proposed by Hummel and Wolfson (1988) is very efficient in a model-based matching system, not only in terms of the computational complexity involved, but also in terms of the simplicity of the method. This paper addresses the implementation of the affine-invariant point matching, applied to the problem of recognizing and determining the pose of sheet metal parts. It points out errors that can occur with this method due to quantization, stability, symmetry, and noise problems. By beginning with an explicit noise model which the Hummel and Wolfson technique lacks, we can derive an optimal approach which overcomes these problems. We show that results obtained with the new algorithm are clearly better than the results from the original method.

  6. Match probabilities in racially admixed populations.

    PubMed Central

    Lange, K

    1993-01-01

    The calculation of match probabilities is the most contentious issue dividing prosecution and defense experts in the forensic applications of DNA fingerprinting. In particular, defense experts question the applicability of the population genetic laws of Hardy-Weinberg and linkage equilibrium to racially admixed American populations. Linkage equilibrium justifies the product rule for computing match probabilities across loci. The present paper suggests a method of bounding match probabilities that depends on modeling gene descent from ancestral populations to contemporary populations under the assumptions of Hardy-Weinberg and linkage equilibrium only in the ancestral populations. Although these bounds are conservative from the defendant's perspective, they should be small enough in practice to satisfy prosecutors. PMID:8430693

  7. Computer-Generated Holographic Matched Filters

    NASA Astrophysics Data System (ADS)

    Butler, Steven Frank

    This dissertation presents techniques for the use of computer-generated holograms (CGH) for matched filtering. An overview of the supporting technology is provided. Included are techniques for modifying existing CGH algorithms to serve as matched filters in an optical correlator. It shows that matched filters produced in this fashion can be modified to improve the signal-to-noise and efficiency over that possible with conventional holography. The effect and performance of these modifications are demonstrated. In addition, a correction of film non-linearity in continuous -tone filter production is developed. Computer simulations provide quantitative and qualitative demonstration of theoretical principles, with specific examples validated in optical hardware. Conventional and synthetic holograms, both bleached and unbleached, are compared.

  8. Anatomy Ontology Matching Using Markov Logic Networks

    PubMed Central

    Li, Chunhua; Zhao, Pengpeng; Wu, Jian; Cui, Zhiming

    2016-01-01

    The anatomy of model species is described in ontologies, which are used to standardize the annotations of experimental data, such as gene expression patterns. To compare such data between species, we need to establish relationships between ontologies describing different species. Ontology matching is a kind of solutions to find semantic correspondences between entities of different ontologies. Markov logic networks which unify probabilistic graphical model and first-order logic provide an excellent framework for ontology matching. We combine several different matching strategies through first-order logic formulas according to the structure of anatomy ontologies. Experiments on the adult mouse anatomy and the human anatomy have demonstrated the effectiveness of proposed approach in terms of the quality of result alignment. PMID:27382498

  9. Active testing search for point cloud matching.

    PubMed

    Pinheiro, Miguel Amável; Sznitman, Raphael; Serradell, Eduard; Kybic, Jan; Moreno-Noguer, Francesc; Fua, Pascal

    2013-01-01

    We present a general approach for solving the point-cloud matching problem for the case of mildly nonlinear transformations. Our method quickly finds a coarse approximation of the solution by exploring a reduced set of partial matches using an approach to which we refer to as Active Testing Search (ATS). We apply the method to registration of graph structures by branching point matching. It is based solely on the geometric position of the points, no additional information is used nor the knowledge of an initial alignment. In the second stage, we use dynamic programming to refine the solution. We tested our algorithm on angiography, retinal fundus, and neuronal data gathered using electron and light microscopy. We show that our method solves cases not solved by most approaches, and is faster than the remaining ones.

  10. Monolithic integration of rare-earth oxides and semiconductors for on-silicon technology

    SciTech Connect

    Dargis, Rytis Clark, Andrew; Erdem Arkun, Fevzi; Grinys, Tomas; Tomasiunas, Rolandas; O'Hara, Andy; Demkov, Alexander A.

    2014-07-01

    Several concepts of integration of the epitaxial rare-earth oxides into the emerging advanced semiconductor on silicon technology are presented. Germanium grows epitaxially on gadolinium oxide despite lattice mismatch of more than 4%. Additionally, polymorphism of some of the rare-earth oxides allows engineering of their crystal structure from hexagonal to cubic and formation of buffer layers that can be used for growth of germanium on a lattice matched oxide layer. Molecular beam epitaxy and metal organic chemical vapor deposition of gallium nitride on the rare-earth oxide buffer layers on silicon is discussed.

  11. Second harmonic conversion in cubic silicon carbide at 1.06 micron

    NASA Technical Reports Server (NTRS)

    Harris, G. L.; Jones, E. W.; Spencer, M. G.; Jackson, K. H.

    1991-01-01

    This letter describes second harmonic conversion in cubic silicon carbide (beta-SiC) at a wavelength of 1.06 micron. Epitaxial layers of beta-SiC formed by vapor phase growth on silicon are indeed birefringent, and thus phase matchable. Phase-matched films of beta-SiC have respectable conversion efficiencies even in the presence of adsorption at 532 nm. The measured value of the effective second order nonlinear susceptibility for beta-SiC is chi super (2) eff = 1.05 +/- 0.3 x 10 exp -9 esu.

  12. Impedance match for Stirling type cryocoolers

    NASA Astrophysics Data System (ADS)

    Dai, Wei; Luo, Ercang; Wang, Xiaotao; Wu, Zhanghua

    Impedance match in Stirling type cryocoolers is important for the compressor efficiency and available acoustic power. This paper generalizes the basic principles concerning the efficiency and acoustic power output of the linear compressor. Starting from basic governing equations and mainly from the viewpoint of energy balance, the physical mechanisms behind the principles are clearly shown. Specially, this paper focuses on the impedance match for an existing compressor, where the current limit and displacement limit should also be taken into consideration when selecting a suitable impedance. Some case studies based on a commercial compressor are also provided for a deep understanding.

  13. Famous face recognition, face matching, and extraversion.

    PubMed

    Lander, Karen; Poyarekar, Siddhi

    2015-01-01

    It has been previously established that extraverts who are skilled at interpersonal interaction perform significantly better than introverts on a face-specific recognition memory task. In our experiment we further investigate the relationship between extraversion and face recognition, focusing on famous face recognition and face matching. Results indicate that more extraverted individuals perform significantly better on an upright famous face recognition task and show significantly larger face inversion effects. However, our results did not find an effect of extraversion on face matching or inverted famous face recognition.

  14. Matching Sailors to Positions Based on Skill

    DTIC Science & Technology

    2007-07-01

    NECs in Sailor’s inventory primary NEC ( PNEC ), secondary NEC (SNEC), tertiary NEC (TNEC), quaternary NEC (NEC4), quinary NEC (NEC5). In this case...pass, then the PNEC alone will be considered for a match with all other single NEC positions. o If the PNEC is not matched in this run, then...100; ELSEIF PG(i) =PG(j) THEN pgmatch(i,j)=100; Comment: Will only show case where Primary and Secondary NECs required IF PNEC (j) = ONEOF

  15. Similarity Based Semantic Web Service Match

    NASA Astrophysics Data System (ADS)

    Peng, Hui; Niu, Wenjia; Huang, Ronghuai

    Semantic web service discovery aims at returning the most matching advertised services to the service requester by comparing the semantic of the request service with an advertised service. The semantic of a web service are described in terms of inputs, outputs, preconditions and results in Ontology Web Language for Service (OWL-S) which formalized by W3C. In this paper we proposed an algorithm to calculate the semantic similarity of two services by weighted averaging their inputs and outputs similarities. Case study and applications show the effectiveness of our algorithm in service match.

  16. Method of forming buried oxide layers in silicon

    DOEpatents

    Sadana, Devendra Kumar; Holland, Orin Wayne

    2000-01-01

    A process for forming Silicon-On-Insulator is described incorporating the steps of ion implantation of oxygen into a silicon substrate at elevated temperature, ion implanting oxygen at a temperature below 200.degree. C. at a lower dose to form an amorphous silicon layer, and annealing steps to form a mixture of defective single crystal silicon and polycrystalline silicon or polycrystalline silicon alone and then silicon oxide from the amorphous silicon layer to form a continuous silicon oxide layer below the surface of the silicon substrate to provide an isolated superficial layer of silicon. The invention overcomes the problem of buried isolated islands of silicon oxide forming a discontinuous buried oxide layer.

  17. Silicone Cerenkov-Radiator Material

    NASA Technical Reports Server (NTRS)

    Balasubrahmanyan, V.; Ormes, J. F.; Streitmatter, R. E.

    1984-01-01

    Dyes enhance visible output. Three fluorescent dyes combine to increase output of silicone material that normally has low yield of visible Cerenkov radiation by converting large amount of available ultraviolet photons into visible light.

  18. RF shaping of silicon ribbon

    NASA Technical Reports Server (NTRS)

    Pelhank, D. A.; Rochat, R. D.; Marx, W.

    1976-01-01

    Electromagnetic force generated by radiofrequency coil is used to shape molten silicon. Shaping coil surrounds melt near solid-liquid interface and induces current in surface region of melt nearly equal to but opposite coil current.

  19. Removing Silicone Grease from Glassware

    NASA Astrophysics Data System (ADS)

    Lowry, Thomas H.

    1997-07-01

    A recent note in this Journal (1) described the use of 5% aqueous hydrofluoric acid for removing silicone grease residues from round-bottom flasks. A safer and more convenient alternative is a saturated solution of sodium hydroxide in ethanol.

  20. Polypropylene vs silicone Ahmed valve with adjunctive mitomycin C in paediatric age group: a prospective controlled study

    PubMed Central

    El Sayed, Y; Awadein, A

    2013-01-01

    Purpose To compare the results of silicone and polypropylene Ahmed glaucoma valves (AGV) implanted during the first 10 years of life. Methods A prospective study was performed on 50 eyes of 33 patients with paediatric glaucoma. Eyes were matched to either polypropylene or silicone AGV. In eyes with bilateral glaucoma, one eye was implanted with polypropylene and the other eye was implanted with silicone AGV. Results Fifty eyes of 33 children were reviewed. Twenty five eyes received a polypropylene valve, and 25 eyes received a silicone valve. Eyes implanted with silicone valves achieved a significantly lower intraocular pressure (IOP) compared with the polypropylene group at 6 months, 1 year, and 2 years postoperatively. The average survival time was significantly longer (P=0.001 by the log-rank test) for the silicone group than for the polypropylene group and the cumulative probability of survival by the log-rank test at the end of the second year was 80% (SE: 8.0, 95% confidence interval (CI): 64–96%) in the silicone group and 56% (SE: 9.8, 95% CI: 40–90%) in the polypropylene group. The difference in the number of postoperative interventions and complications between both groups was statistically insignificant. Conclusion Silicone AGVs can achieve better IOP control, and longer survival with less antiglaucoma drops compared with polypropylene valves in children younger than 10 years. PMID:23579403

  1. Silicon carbide-silicon composite having improved oxidation resistance and method of making

    NASA Technical Reports Server (NTRS)

    Luthra, Krishan Lal (Inventor); Wang, Hongyu (Inventor)

    1999-01-01

    A Silicon carbide-silicon matrix composite having improved oxidation resistance at high temperatures in dry or water-containing environments is provided. A method is given for sealing matrix cracks in situ in melt infiltrated silicon carbide-silicon matrix composites. The composite cracks are sealed by the addition of various additives, such as boron compounds, into the melt infiltrated silicon carbide-silicon matrix.

  2. Method of making silicon carbide-silicon composite having improved oxidation resistance

    NASA Technical Reports Server (NTRS)

    Luthra, Krishan Lal (Inventor); Wang, Hongyu (Inventor)

    2002-01-01

    A Silicon carbide-silicon matrix composite having improved oxidation resistance at high temperatures in dry or water-containing environments is provided. A method is given for sealing matrix cracks in situ in melt infiltrated silicon carbide-silicon matrix composites. The composite cracks are sealed by the addition of various additives, such as boron compounds, into the melt infiltrated silicon carbide-silicon matrix.

  3. Intrinsic Magnetism at Silicon Surfaces

    DTIC Science & Technology

    2010-08-24

    localized at silicon step edges having the form of graphitic ribbons. The predicted magnetic state is supported by recent experimental observations... carbon , silicon and oxygen — can also reveal unpaired elec- trons when covalent bonds are broken. In defective or disordered group IV solids, the single...investigated for magnetism experimentally, but we show below that existing data already support it indirectly. Results Spin polarization at graphitic steps

  4. Lung embolism with liquid silicone.

    PubMed

    Rodríguez, M A; Martínez, M C; Lopez-Artíguez, M; Soria, M L; Bernier, F; Repetto, M

    1989-03-01

    A lung embolism was reported in a case involving death following repeated injections of liquid silicone for aesthetic reasons. The liquid extracted from the sites of injection was identified as methylsilicone using infrared spectrophotometry, and the presence of silicone in vacuoles in the lung was verified by scanning electron microscopy with energy dispersive X-ray analysis (EDXA). A study has been carried out with rats after intravenous and subcutaneous injections of methylsilicone.

  5. Silicone nanocomposite coatings for fabrics

    NASA Technical Reports Server (NTRS)

    Eberts, Kenneth (Inventor); Lee, Stein S. (Inventor); Singhal, Amit (Inventor); Ou, Runqing (Inventor)

    2011-01-01

    A silicone based coating for fabrics utilizing dual nanocomposite fillers providing enhanced mechanical and thermal properties to the silicone base. The first filler includes nanoclusters of polydimethylsiloxane (PDMS) and a metal oxide and a second filler of exfoliated clay nanoparticles. The coating is particularly suitable for inflatable fabrics used in several space, military, and consumer applications, including airbags, parachutes, rafts, boat sails, and inflatable shelters.

  6. Low cost silicon solar arrays

    NASA Technical Reports Server (NTRS)

    Ravi, K. V.; Serreze, H. B.; Bates, H. E.; Morrison, A. D.; Jewett, D. N.; Ho, J. C. T.; Schwuttke, G. H.; Ciszek, T. F.; Kran, A.

    1975-01-01

    Continuous growth methodology for silicon solar cell ribbons deals with capillary effects, die effects, thermal effects and crystal shape effects. Emphasis centers on the shape of the meniscus at the ribbon edge as a factor contributing to ribbon quality with respect to defect densities. Structural and electrical characteristics of edge defined, film-fed grown silicon ribbons are elaborated. Ribbon crystal solar cells produce AMO efficiencies of 6 to 10%.

  7. Silicon superconducting quantum interference device

    SciTech Connect

    Duvauchelle, J. E.; Francheteau, A.; Marcenat, C.; Lefloch, F.; Chiodi, F.; Débarre, D.; Hasselbach, K.; Kirtley, J. R.

    2015-08-17

    We have studied a Superconducting Quantum Interference Device (SQUID) made from a single layer thin film of superconducting silicon. The superconducting layer is obtained by heavily doping a silicon wafer with boron atoms using the gas immersion laser doping technique. The SQUID is composed of two nano-bridges (Dayem bridges) in a loop and shows magnetic flux modulation at low temperature and low magnetic field. The overall behavior shows very good agreement with numerical simulations based on the Ginzburg-Landau equations.

  8. Metallization of Large Silicon Wafers

    NASA Technical Reports Server (NTRS)

    Pryor, R. A.

    1978-01-01

    A metallization scheme was developed which allows selective plating of silicon solar cell surfaces. The system is comprised of three layers. Palladium, through the formation of palladium silicide at 300 C in nitrogen, makes ohmic contact to the silicon surface. Nickel, plated on top of the palladium silicide layer, forms a solderable interface. Lead-tin solder on the nickel provides conductivity and allows a convenient means for interconnection of cells. To apply this metallization, three chemical plating baths are employed.

  9. Silicone-Rubber Stitching Seal

    NASA Technical Reports Server (NTRS)

    Wang, D. S.

    1985-01-01

    Fabric products protected from raveling by coating threads and filling stitching holes with silicone rubber. Uncored silicone rubber applied to stitching lines with air-pressurized sealant gun. Next, plastic release film placed on coated side, and blanket flipped over so release film lies underneath. Blanket then bagged and adhesive cured under partial vacuum of about 3.5 psi or under pressure. Applications include balloons, parachutes, ultralight aircraft, sails, rescue harnesses, tents, or other fabric products highly stressed in use.

  10. Silicon Hot-Electron Bolometers

    NASA Technical Reports Server (NTRS)

    Stevenson, Thomas R.; Hsieh, Wen-Ting; Mitchell, Robert R.; Isenberg, Hal D.; Stahle, Carl M.; Cao, Nga T.; Schneider, Gideon; Travers, Douglas E.; Moseley, S. Harvey; Wollack, Edward J.

    2004-01-01

    We discuss a new type of direct detector, a silicon hot-electron bolometer, for measurements in the far-infrared and submillimeter spectral ranges. High performance bolometers can be made using the electron-phonon conductance in heavily doped silicon to provide thermal isolation from the cryogenic bath. Noise performance is expected to be near thermodynamic limits, allowing background limited performance for many far infrared and submillimeter photometric and spectroscopic applications.

  11. Ground based silicon zoning program

    NASA Technical Reports Server (NTRS)

    Kern, E. L.

    1981-01-01

    The preparation of building flight hardware and carrying out experiments in space was investigated. The ground based investigation phase A/B of the experimental float zoning of silicon is outlined. The overall program goals, leading to recommending experiments to be done in phase C/D are spelled out. Thermophysical properties which must be accurately known to compare thermophysical models to experimental zoning of silicon are listed.

  12. Magnetically retained silicone facial prosthesis.

    PubMed

    Venugopalan, S; Ariga, P; Aggarwal, P; Viswanath, A

    2014-01-01

    Patients with orocutaneous fistulas suffer from discomfort in terms of facial esthetics, food spill over and lack of psychological confidence to present them socially. Prosthetic camouflaging of facial defects and use of silicone maxillofacial material are the alternatives to the surgical retreatment. Silicone elastomers provide more options to clinician for customization of the facial prosthesis which is simple, esthetically good when coupled with bio magnets for retention.

  13. Thematic Matching as Remedial Teaching for Symbolic Matching for Individuals with Autism Spectrum Disorder

    PubMed Central

    Lionello-DeNolf, Karen M.; Farber, Rachel; Jones, B. Max; Dube, William V.

    2014-01-01

    Matching-to-sample (MTS) is often used to teach symbolic relationships between spoken or printed words and their referents to children with intellectual and developmental disabilities. However, many children have difficulty learning symbolic matching, even though they may demonstrate generalized identity matching. The current study investigated whether training on symbolic MTS tasks in which the stimuli are physically dissimilar but members of familiar categories (i.e., thematic matching) can remediate an individual’s difficulty learning symbolic MTS tasks involving non-representative stimuli. Three adolescent males diagnosed with autism spectrum disorder were first trained on symbolic MTS tasks with unfamiliar, non-representative form stimuli. Thematic matching was introduced after the participants failed to learn 0, 2 or 4 symbolic MTS tasks and before additional symbolic MTS tasks were introduced. After exposure to thematic matching, accuracy on symbolic MTS tasks with novel stimuli increased to above chance for all participants. For two participants, high accuracy (> 90%) was achieved on a majority of these sessions. Thus, thematic matching may be an effective intervention for students with limited verbal repertoires and who have difficulty learning symbolic MTS tasks. Possible explanations for the facilitative effect of thematic matching are considered and warrant further investigation. PMID:24634695

  14. Emergent Identity Matching after Successive Matching Training. II: Reflexivity or Transitivity?

    ERIC Educational Resources Information Center

    Urcuioli, Peter J.; Swisher, Melissa

    2012-01-01

    Three experiments evaluated whether the apparent reflexivity effect reported by Sweeney and Urcuioli (2010) for pigeons might, in fact, be transitivity. In Experiment 1, pigeons learned symmetrically reinforced hue-form (A-B) and form-hue (B-A) successive matching. Those also trained on form-form (B-B) matching responded more to hue comparisons…

  15. Therapist-Worldview Matching: Not as Important as Matching to Clients

    ERIC Educational Resources Information Center

    Blow, Adrian J.; Davis, Sean D.; Sprenkle, Douglas H.

    2012-01-01

    In this essay, we respond to Simon's article (2012). We discuss our view that therapy works best when therapists can match therapeutic interventions to the worldview of clients. We see this matching to client worldview as rooted in research evidence, and we suggest that therapists can practice authentically and effectively using more than one…

  16. SU-8 photoresist and SU-8 based nanocomposites for broadband acoustical matching at 1 GHz

    NASA Astrophysics Data System (ADS)

    Ndieguene, A.; Campistron, P.; Carlier, J.; Wang, S.; Callens-Debavelaere, D.; Nongaillard, B.

    2009-11-01

    So as to integrate acoustic functions in BioMEMS using 1 GHz ZnO transducers deposited on silicon substrates, acoustic waves propagation through the silicon substrate and its transmission in water needs to be maximized (the insertion losses at the Si / water interface are about 6dB). In the context of integration, it is interesting for mechanical impedance matching to use photosensitive materials such as SU-8 so that patterns may be obtained. Nanocomposite materials based on SU-8 mixed with nanoparticles having adequate impedances were fabricated. These new materials are characterized in terms of their acoustic velocity, impedance and attenuation. For this, the nanocomposite layers are deposited on the substrate by spin coating to obtain a thickness of about 10 μm, in order to separate acoustic echoes from the material (even if λ/4 layer thickness is lower than 1 μm). The insertion losses of the device immersed in water can be simulated as a function of frequency for a given reflection coefficient between the silicon substrate and the photoresist. The characteristics of some nanocomposites made with SU-8 and various concentrations of nanoparticles like Ti02, SrTiO3 or W have been determined.

  17. Polycrystalline silicon on tungsten substrates

    NASA Technical Reports Server (NTRS)

    Bevolo, A. J.; Schmidt, F. A.; Shanks, H. R.; Campisi, G. J.

    1979-01-01

    Thin films of electron-beam-vaporized silicon were deposited on fine-grained tungsten substrates under a pressure of about 1 x 10 to the -10th torr. Mass spectra from a quadrupole residual-gas analyzer were used to determine the partial pressure of 13 residual gases during each processing step. During separate silicon depositions, the atomically clean substrates were maintained at various temperatures between 400 and 780 C, and deposition rates were between 20 and 630 A min. Surface contamination and interdiffusion were monitored by in situ Auger electron spectrometry before and after cleaning, deposition, and annealing. Auger depth profiling, X-ray analysis, and SEM in the topographic and channeling modes were utilized to characterize the samples with respect to silicon-metal interface, interdiffusion, silicide formation, and grain size of silicon. The onset of silicide formation was found to occur at approximately 625 C. Above this temperature tungsten silicides were formed at a rate faster than the silicon deposition. Fine-grain silicon films were obtained at lower temperatures.

  18. Guided photoluminescence study of Nd-doped silicon rich silicon oxide and silicon rich silicon nitride waveguides

    NASA Astrophysics Data System (ADS)

    Pirasteh, Parastesh; Charrier, Joël; Dumeige, Yannick; Doualan, Jean-Louis; Camy, Patrice; Debieu, Olivier; Liang, Chuan-hui; Khomenkova, Larysa; Lemaitre, Jonathan; Boucher, Yann G.; Gourbilleau, Fabrice

    2013-07-01

    Planar waveguides made of Nd3+-doped silicon rich silicon oxide (SRSO) and silicon rich silicon nitride (SRSN) have been fabricated by reactive magnetron sputtering and characterized with special emphasis on the comparison of the guided photoluminescence (PL) properties of these two matrices. Guided fluorescence excited by top surface pumping at 488 nm on planar waveguides was measured as a function of the distance between the excitation area and the output of the waveguide, as well as a function of the pump power density. The PL intensity increased linearly with pump power without any saturation even at high power. The linear intensity increase of the Nd3+ guided PL under a non-resonant excitation (488 nm) confirms the efficient coupling between either Si-np and rare-earth ions for SRSO or radiative defects and rare earth ions for SRSN. The guided fluorescences at 945 and 1100 nm were observed until 4 mm and 8 mm of the output of the waveguide for Nd3+ doped SRSO and SRSN waveguides, respectively. The guided fluorescence decays of Nd3+-doped-SRSO and -SRSN planar waveguides have been measured and found equal to 97 μs ±7 and 5 μs ± 2, respectively. These results show notably that the Nd3+-doped silicon rich silicon oxide is a very promising candidate on the way to achieve a laser cavity at 1.06 μm.

  19. Matching Instructional Design with Vocabulary Instruction

    ERIC Educational Resources Information Center

    Nichols, William Dee; Rupley, William H.

    2004-01-01

    Instructional design is an integral part of a balanced approach to teaching vocabulary instruction. The goal of this paper is to reflect on several lessons using research-based vocabulary strategies, and to present think-alouds that detail the steps in matching instructional design with those strategies in order to reach the learning outcome.…

  20. Accuracy and robustness evaluation in stereo matching

    NASA Astrophysics Data System (ADS)

    Nguyen, Duc M.; Hanca, Jan; Lu, Shao-Ping; Schelkens, Peter; Munteanu, Adrian

    2016-09-01

    Stereo matching has received a lot of attention from the computer vision community, thanks to its wide range of applications. Despite of the large variety of algorithms that have been proposed so far, it is not trivial to select suitable algorithms for the construction of practical systems. One of the main problems is that many algorithms lack sufficient robustness when employed in various operational conditions. This problem is due to the fact that most of the proposed methods in the literature are usually tested and tuned to perform well on one specific dataset. To alleviate this problem, an extensive evaluation in terms of accuracy and robustness of state-of-the-art stereo matching algorithms is presented. Three datasets (Middlebury, KITTI, and MPEG FTV) representing different operational conditions are employed. Based on the analysis, improvements over existing algorithms have been proposed. The experimental results show that our improved versions of cross-based and cost volume filtering algorithms outperform the original versions with large margins on Middlebury and KITTI datasets. In addition, the latter of the two proposed algorithms ranks itself among the best local stereo matching approaches on the KITTI benchmark. Under evaluations using specific settings for depth-image-based-rendering applications, our improved belief propagation algorithm is less complex than MPEG's FTV depth estimation reference software (DERS), while yielding similar depth estimation performance. Finally, several conclusions on stereo matching algorithms are also presented.