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Sample records for volume percent silicon

  1. Comparing proton conductivity of polymer electrolytes by percent conducting volume

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yu Seung [Los Alamos National Laboratory; Pivovar, Bryan [NREL

    2009-01-01

    Proton conductivity of sulfonated polymers plays a key role in polymer electrolyte membrane fuel cells. Mass based water uptake and ion exchange capacity of sulfonated polymers have been failed to correlating their proton conductivity. In this paper, we report a length scale parameter, percent conductivity volume, which is rather simply obtained from the chemical structure of polymer to compare proton conductivity of wholly aromatic sulfonated polymer perflurosulfonic acid. Morphology effect on proton conductivity at lower RH conditions is discussed using the percent conductivity volume parameter.

  2. Large volume cryogenic silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Braggio, C. [Dipartimento di Fisica, Universita di Padova, via Marzolo 8, 35131 Padova (Italy); Boscardin, M. [Fondazione Bruno Kessler (FBK), via Sommarive 18, I-38100 Povo (Italy); Bressi, G. [INFN sez. di Pavia, via Bassi 6, 27100 Pavia (Italy); Carugno, G.; Corti, D. [INFN sez. di Padova, via Marzolo 8, 35131 Padova (Italy); Galeazzi, G. [INFN lab. naz. Legnaro, viale dell' Universita 2, 35020 Legnaro (Italy); Zorzi, N. [Fondazione Bruno Kessler (FBK), via Sommarive 18, I-38100 Povo (Italy)

    2009-12-15

    We present preliminary measurements for the development of a large volume silicon detector to detect low energy and low rate energy depositions. The tested detector is a one cm-thick silicon PIN diode with an active volume of 31 cm{sup 3}, cooled to the liquid helium temperature to obtain depletion from thermally-generated free carriers. A thorough study has been done to show that effects of charge trapping during drift disappears at a bias field value of the order of 100V/cm.

  3. Ultrasonic methods for measuring liquid viscosity and volume percent of solids

    Energy Technology Data Exchange (ETDEWEB)

    Sheen, S.H.; Chien, H.T.; Raptis, A.C.

    1997-02-01

    This report describes two ultrasonic techniques under development at Argonne National Laboratory (ANL) in support of the tank-waste transport effort undertaken by the U.S. Department of Energy in treating low-level nuclear waste. The techniques are intended to provide continuous on-line measurements of waste viscosity and volume percent of solids in a waste transport line. The ultrasonic technique being developed for waste-viscosity measurement is based on the patented ANL viscometer. Focus of the viscometer development in this project is on improving measurement accuracy, stability, and range, particularly in the low-viscosity range (<30 cP). A prototype instrument has been designed and tested in the laboratory. Better than 1% accuracy in liquid density measurement can be obtained by using either a polyetherimide or polystyrene wedge. To measure low viscosities, a thin-wedge design has been developed and shows good sensitivity down to 5 cP. The technique for measuring volume percent of solids is based on ultrasonic wave scattering and phase velocity variation. This report covers a survey of multiple scattering theories and other phenomenological approaches. A theoretical model leading to development of an ultrasonic instrument for measuring volume percent of solids is proposed, and preliminary measurement data are presented.

  4. Auger electron spectroscopy study of surface segregation in the binary alloys copper-1 atomic percent indium, copper-2 atomic percent tin, and iron-6.55 atomic percent silicon

    Science.gov (United States)

    Ferrante, J.

    1973-01-01

    Auger electron spectroscopy was used to examine surface segregation in the binary alloys copper-1 at. % indium, copper-2 at. % tin and iron-6.55 at. % silicon. The copper-tin and copper-indium alloys were single crystals oriented with the /111/ direction normal to the surface. An iron-6.5 at. % silicon alloy was studied (a single crystal oriented in the /100/ direction for study of a (100) surface). It was found that surface segregation occurred following sputtering in all cases. Only the iron-silicon single crystal alloy exhibited equilibrium segregation (i.e., reversibility of surface concentration with temperature) for which at present we have no explanation. McLean's analysis for equilibrium segregation at grain boundaries did not apply to the present results, despite the successful application to dilute copper-aluminum alloys. The relation of solute atomic size and solubility to surface segregation is discussed. Estimates of the depth of segregation in the copper-tin alloy indicate that it is of the order of a monolayer surface film.

  5. Channeling, volume reflection, and volume capture study of electrons in a bent silicon crystal

    DEFF Research Database (Denmark)

    Wistisen, T. N.; Uggerhoj, U. I.; Wienands, U.;

    2016-01-01

    We present the experimental data and analysis of experiments conducted at SLAC National Accelerator Laboratory investigating the processes of channeling, volume-reflection and volume-capture along the (111) plane in a strongly bent quasimosaic silicon crystal. These phenomena were investigated at...

  6. Thermal properties study on the ablation materials of inorganic silicon compound from organosilicone in high percent conversion

    Institute of Scientific and Technical Information of China (English)

    CUI MengZhong; WANG WenHua

    2007-01-01

    The new type of silicone rubber prepared by organosilicon polymer containing special groups presents the tensile strength of 3.92 MPa and the elongation at break of 285%. Compared with Sylgard(r)184 silicone rubber (Dow Corning Corporation), it has better high temperature resistance and almost no weightlessness from room temperature to 430℃. Thermogravimetric analysis was conducted to research the thermal degradation at different temperatures and the heat pyrolysis products were trace determined by FT-IR. The results show that with the increase of temperature, the organic groups of products are gradually decomposed. Organosilicon rubber is gradually changed into the typical inorganic SiCO compounds in the process of pyrolysis. Elemental analysis and X-ray photoelectron spectroscopy results show that the pyrolyzates are mainly composed of Si, C and O elements above 1050℃. X-ray diffraction analysis showes that partial β-SiC crystal structure is brought about gradually from the pyrolysis products at 1050℃ to 1500℃ under nitrogen atmosphere. With the treatment temperature rising, the crystallinity of SiC and cristobalite obviously increases.

  7. Effect of serum testosterone and percent tumor volume on extra-prostatic extension and biochemical recurrence after laparoscopic radical prostatectomy

    Directory of Open Access Journals (Sweden)

    Eu Chang Hwang

    2016-01-01

    Full Text Available Several studies have revealed that the preoperative serum testosterone and percent tumor volume (PTV predict extra-prostatic extension (EPE and biochemical recurrence (BCR after radical prostatectomy. This study investigated the prognostic significance of serum testosterone and PTV in relation to EPE and BCR after laparoscopic radical prostatectomy (LRP. We reviewed 520 patients who underwent LRP between 2004 and 2012. PTV was determined as the sum of all visually estimated tumor foci in every section. BCR was defined as two consecutive increases in the postoperative prostate-specific antigen (PSA >0.2 ng ml−1 . The threshold for serum total testosterone was 3.0 ng ml−1 . Multivariate logistic regression was used to define the effect of variables on the risk of EPE and BCR. A low serum testosterone (<3.0 ng ml−1 was associated with a high serum PSA, Gleason score, positive core percentage of the prostate biopsy, PTV, and all pathological variables. On multivariate analysis, similar to previous studies, the serum PSA, biopsy positive core percentage, Gleason score, and pathological variables predicted EPE and BCR. In addition, low serum testosterone (<3.0 ng ml−1 , adjusted OR, 8.52; 95% CI, 5.04-14.4, P= 0.001 predicted EPE and PTV (adjusted OR, 1.02; 95% CI, 1.01-1.05, P= 0.046 predicted BCR. In addition to previous predictors of EPE and BCR, low serum testosterone and PTV are valuable predictors of EPE and BCR after LRP.

  8. Correlating the properties of amorphous silicon with its flexibility volume

    Science.gov (United States)

    Fan, Zhao; Ding, Jun; Li, Qing-Jie; Ma, Evan

    2017-04-01

    For metallic glasses, "flexibility volume" has recently been introduced as a property-revealing indicator of the structural state the glass is in. This parameter incorporates the atomic volume and the vibrational mean-square displacement, to combine both static structure and dynamics information. Flexibility volume was shown to quantitatively correlate with the properties of metallic glasses [J. Ding et al., Nat. Commun. 7, 13733 (2016), 10.1038/ncomms13733]. However, it remains to be examined if this parameter is useful for other types of glasses with bonding characteristics, atomic packing structures, as well as properties that are distinctly different from metallic glasses. In this paper, we tackle this issue through systematic molecular-dynamics simulations of amorphous silicon (a -Si) models produced with different cooling rates, as a -Si is a prototypical covalently bonded network glass whose structure and properties cannot be characterized using structural parameters such as free volume used for metallic and polymeric glasses. Specifically, we demonstrate a quantitative prediction of the shear modulus of a -Si from the flexibility for atomic motion. This flexibility volume descriptor, when evaluated on the atomic scale, is shown to also correlate well with local packing, as well as with the propensity for thermal relaxations and shear transformations, providing a metric to map out and explain the structural and mechanical heterogeneity in the amorphous material. This case study of a model of covalently bonded network a -Si, together with our earlier demonstration for metallic glasses, points to the universality of flexibility volume as an indicator of the structure state to link with properties, applicable across amorphous materials with different chemical bonding and atomic packing structures.

  9. Channeling, volume reflection, and volume capture study of electrons in a bent silicon crystal

    Science.gov (United States)

    Wistisen, T. N.; Uggerhøj, U. I.; Wienands, U.; Markiewicz, T. W.; Noble, R. J.; Benson, B. C.; Smith, T.; Bagli, E.; Bandiera, L.; Germogli, G.; Guidi, V.; Mazzolari, A.; Holtzapple, R.; Tucker, S.

    2016-07-01

    We present the experimental data and analysis of experiments conducted at SLAC National Accelerator Laboratory investigating the processes of channeling, volume-reflection and volume-capture along the (111) plane in a strongly bent quasimosaic silicon crystal. These phenomena were investigated at 5 energies: 3.35, 4.2, 6.3, 10.5, and 14.0 GeV with a crystal with bending radius of 0.15 m, corresponding to curvatures of 0.053, 0.066, 0.099, 0.16, and 0.22 times the critical curvature, respectively. Based on the parameters of fitting functions we have extracted important parameters describing the channeling process such as the dechanneling length, the angle of volume reflection, the surface transmission, and the widths of the distribution of channeled particles parallel and orthogonal to the plane.

  10. The percent of cores positive for cancer in prostate needle biopsy specimens is strongly predictive of tumor stage and volume at radical prostatectomy.

    Science.gov (United States)

    Sebo, T J; Bock, B J; Cheville, J C; Lohse, C; Wollan, P; Zincke, H

    2000-01-01

    Pretreatment clinical staging of prostatic adenocarcinoma is important due to the increasing use of nonsurgical treatment options. Using multivariate analysis we assessed the predictive value of biopsy cores positive for cancer as a percent of all cores obtained as well as the percent surface area of needle cores involved with tumor for determining tumor volume and pathological stage at radical prostatectomy. Candidate variables for the multivariate model included patient age, clinical disease stage, serum prostate specific antigen (PSA) and Gleason score of cancer in the needle biopsy. We reviewed prostate needle biopsy findings in 207 consecutive patients who subsequently underwent radical retropubic prostatectomy. Each biopsy specimen was assessed for tumor involvement by calculating the percent of cores positive for cancer, percent surface area involved in all cores and Gleason score. Initial serum PSA and preoperative clinical disease stage were incorporated with biopsy results into a multivariate model to determine the parameters most predictive of pathological stage and tumor volume at radical retropubic prostatectomy. Of the 207 patients 152 (73.4%) had organ confined cancer and 55 (26.6%) had extraprostatic extension (pathological stages T2 and T3 or greater, respectively). Preoperative clinical staging information was available in 195 cases, in which disease was clinically confined and not confined in 184 (94.4%) and 11 (5.6%), respectively. Needle biopsy revealed a surface area of cancer ranging from less than 5% in 69 patients (33.3%) to 90% (mean 16, median 10). Univariate analysis demonstrated that the risk of extraprostatic extension was predicted by preoperative serum PSA (p = 0.027), the percent of cores and percent of surface area positive for cancer (p <0.0001), and Gleason score (p = 0.0009). Clinical stage approached significance (p = 0.071). Multivariate analysis showed that the percent of positive cores (p = 0.0003), initial serum PSA (p = 0

  11. The effects of volume percent and aspect ratio of carbon fiber on fracture toughness of reinforced aluminum matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Naji, H. [Department of Materials and Metallurgical Engineering, Engineering Faculty, Ferdowsi University of Mashhad, Azadi Square, P.O. Box 91775-1111 (Iran, Islamic Republic of); Zebarjad, S.M. [Department of Materials and Metallurgical Engineering, Engineering Faculty, Ferdowsi University of Mashhad, Azadi Square, P.O. Box 91775-1111 (Iran, Islamic Republic of)], E-mail: Zebarjad@ferdowsi.um.ac.ir; Sajjadi, S.A. [Department of Materials and Metallurgical Engineering, Engineering Faculty, Ferdowsi University of Mashhad, Azadi Square, P.O. Box 91775-1111 (Iran, Islamic Republic of)

    2008-07-15

    Carbon fiber reinforced aluminum matrix composites are used as advanced materials in aerospace and electronic industries. In order to investigate role of aspect ratio of carbon fiber on fracture toughness of aluminum matrix composite, the composite was produced using stir casting. Al-8.5%Si-5%Mg selected as a matrix. The samples were prepared with three volume fractions (1, 2 and 3) and three aspect ratios (300, 500 and 800). Three-point bending test was performed on the specimens to evaluate the fracture toughness of the materials. The results showed that the fracture toughness of composites depends on both fiber volume fraction and aspect ratio. Scanning electron microscopy (SEM) was employed to elucidate the fracture behavior and crack deflection of composites. The study also, showed that the toughening mechanism depends strongly on fiber volume fraction, aspect ratio and the degree of wetting between fiber and matrix.

  12. Large volume liquid silicone injection in the upper thighs : a never ending story

    NARCIS (Netherlands)

    Hofer, SOP; Damen, A; Nicolai, JPA

    2000-01-01

    This report concerns a 26-year-old male-to-female transsexual who had received a large volume liquid silicone injection of unknown grade into her upper lateral thighs to gain female contour. She presented at our outpatient clinic 4 years after the silicone injection with complaints of pain and silic

  13. Subject positioning in the BOD POD® only marginally affects measurement of body volume and estimation of percent body fat in young adult men.

    Directory of Open Access Journals (Sweden)

    Maarten W Peeters

    Full Text Available INTRODUCTION: The aim of the study was to evaluate whether subject positioning would affect the measurement of raw body volume, thoracic gas volume, corrected body volume and the resulting percent body fat as assessed by air displacement plethysmography (ADP. METHODS: Twenty-five young adult men (20.7±1.1 y, BMI = 22.5±1.4 kg/m(2 were measured using the BOD POD® system using a measured thoracic gas volume sitting in a 'forward bent' position and sitting up in a straight position in random order. RESULTS: Raw body volume was 58±124 ml (p<0.05 higher in the 'straight' position compared to the 'bent' position. The mean difference in measured thoracic gas volume (bent-straight = -71±211 ml was not statistically significant. Corrected body volume and percent body fat in the bent position consequently were on average 86±122 ml (p<0.05 and 0.5±0.7% (p<0.05 lower than in the straight position respectively. CONCLUSION: Although the differences reached statistical significance, absolute differences are rather small. Subject positioning should be viewed as a factor that may contribute to between-test variability and hence contribute to (inprecision in detecting small individual changes in body composition, rather than a potential source of systematic bias. It therefore may be advisable to pay attention to standardizing subject positioning when tracking small changes in PF are of interest. The cause of the differences is shown not to be related to changes in the volume of isothermal air in the lungs. It is hypothesized and calculated that the observed direction and magnitude of these differences may arise from the surface area artifact which does not take into account that a subject in the bent position exposes more skin to the air in the device therefore potentially creating a larger underestimation of the actual body volume due to the isothermal effect of air close to the skin.

  14. Controlled Directional Solidification of Aluminum - 7 wt Percent Silicon Alloys: Comparison Between Samples Processed on Earth and in the Microgravity Environment Aboard the International Space Station

    Science.gov (United States)

    Grugel, Richard N.; Tewari, Surendra N.; Erdman, Robert G.; Poirier, David R.

    2012-01-01

    An overview of the international "MIcrostructure Formation in CASTing of Technical Alloys" (MICAST) program is given. Directional solidification processing of metals and alloys is described, and why experiments conducted in the microgravity environment aboard the International Space Station (ISS) are expected to promote our understanding of this commercially relevant practice. Microstructural differences observed when comparing the aluminum - 7 wt% silicon alloys directionally solidified on Earth to those aboard the ISS are presented and discussed.

  15. SU-E-T-562: Scanned Percent Depth Dose Curve Discrepancy for Photon Beams with Physical Wedge in Place (Varian IX) Using Different Sensitive Volume Ion Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, H; Sarkar, V; Rassiah-Szegedi, P; Huang, Y; Szegedi, M; Huang, L; Salter, B [University Utah, Salt Lake City, UT (United States)

    2014-06-01

    Purpose: To investigate and report the discrepancy of scanned percent depth dose (PDD) for photon beams with physical wedge in place when using ion chambers with different sensitive volumes. Methods/Materials: PDD curves of open fields and physical wedged fields (15, 30, 45, and 60 degree wedge) were scanned for photon beams (6MV and 10MV, Varian iX) with field size of 5x5 and 10x10 cm using three common scanning chambers with different sensitive volumes - PTW30013 (0.6cm3), PTW23323 (0.1cm3) and Exradin A16 (0.007cm3). The scanning system software used was OmniPro version 6.2, and the scanning water tank was the Scanditronix Wellhoffer RFA 300.The PDD curves from the three chambers were compared. Results: Scanned PDD curves of the same energy beams for open fields were almost identical between three chambers, but the wedged fields showed non-trivial differences. The largest differences were observed between chamber PTW30013 and Exradin A16. The differences increased as physical wedge angle increased. The differences also increased with depth, and were more pronounced for 6MV beam. Similar patterns were shown for both 5x5 and 10x10 cm field sizes. For open fields, all PDD values agreed with each other within 1% at 10cm depth and within 1.62% at 20 cm depth. For wedged fields, the difference of PDD values between PTW30013 and A16 reached 4.09% at 10cm depth, and 5.97% at 20 cm depth for 6MV with 60 degree physical wedge. Conclusion: We observed a significant difference in scanned PDD curves of photon beams with physical wedge in place obtained when using different sensitive volume ion chambers. The PDD curves scanned with the smallest sensitive volume ion chamber showed significant difference from larger chamber results, beyond 10cm depth. We believe this to be caused by varying response to beam hardening by the wedges.

  16. Detachment of Tertiary Dendrite Arms during Controlled Directional Solidification in Aluminum - 7 wt Percent Silicon Alloys: Observations from Ground-based and Microgravity Processed Samples

    Science.gov (United States)

    Grugel, Richard N.; Erdman, Robert; Van Hoose, James R.; Tewari, Surendra; Poirier, David

    2012-01-01

    Electron Back Scattered Diffraction results from cross-sections of directionally solidified aluminum 7wt% silicon alloys unexpectedly revealed tertiary dendrite arms that were detached and mis-oriented from their parent arm. More surprisingly, the same phenomenon was observed in a sample similarly processed in the quiescent microgravity environment aboard the International Space Station (ISS) in support of the joint US-European MICAST investigation. The work presented here includes a brief introduction to MICAST and the directional solidification facilities, and their capabilities, available aboard the ISS. Results from the ground-based and microgravity processed samples are compared and possible mechanisms for the observed tertiary arm detachment are suggested.

  17. Percent {alpha} and {beta} phases present in the silicon nitride powder produced through intermediary silicon di imide; Estudo da porcentagem de fases {alpha} e {beta} presentes no po de nitreto de silicio produzido via intermediario diimida de silicio

    Energy Technology Data Exchange (ETDEWEB)

    Cavalcanti, Celso Berilo Cidade; Piorino Neto, Francisco; Shibuya, Hissao; Silva, Vitor Alexandre da; Silva, Cosme Roberto Moreira da [Centro Tecnico Aeroespacial, Sao Jose dos Campos, SP (Brazil). Inst. de Aeronautica e Espaco

    1995-12-31

    Ceramic powder must have appropriated characteristics which allow good mechanical final properties of the sintered material. The {alpha}/{beta} relationship on the starting powders is very important when we want to improve the fracture toughness. The present work evaluates the phase relationships on silicon nitride powder, produced by ammonolysis of silicon tetrachloride, by imide step, with variation of temperature and time of dimide pyrolysis. The synthesis condition was monitored and the existing {beta}-phases for the used conditions remained between 15 and 25%. (author) 1 tab.

  18. Czochralski Silicon as a Detector Material for S-LHC Tracker Volumes

    CERN Document Server

    Spiegel, Leonard; Betchart, Burt; Bhattacharya, Saptaparna; Czellar, Sandor; Demina, Regina; Dierlamm, Alexander; Frey, Martin; Gotra, Yuri; Härkönen, Jaakko; Hartmann, Frank; Kassamakov, Ivan; Korjenevski, Sergey; Kortelainen, Matti J; Lampén, Tapio; Luukka, Panja; Mäenpää, Teppo; Moilanen, Henri; Narain, Meenakshi; Neuland, Maike; Orbaker, Douglas; Simonis, Hans-Jürgen; Steck, Pia; Tuominen, Eija; Tuovinen, Esa

    2011-01-01

    With an expected ten-fold increase in luminosity in S-LHC, the radiation environment in the tracker volumes will be considerably harsher for silicon-based detectors than the already harsh LHC environment. Since 2006, a group of CMS institutes, using a modified CMS DAQ system, has been exploring the use of Magnetic Czochralski silicon as a detector element for the strip tracker layers in S-LHC experiments. Both p+/n-/n+ and n+/p-/p+ sensors have been characterized, irradiated with proton and neutron sources, assembled into modules, and tested in a CERN beamline. There have been three beam studies to date and results from these suggest that both p+/n-/n+ and n+/p-/p+ Magnetic Czochralski silicon are sufficiently radiation hard for the $R>25$ cm regions of S-LHC tracker volumes. The group has also explored the use of forward biasing for heavily irradiated detectors, and although this mode requires sensor temperatures less than -50\\,$^\\circ$C, the charge collection efficiency appears to be promising.

  19. Channeling, Volume Reection and Gamma Emission Using 14GeV Electrons in Bent Silicon Crystals

    Energy Technology Data Exchange (ETDEWEB)

    Benson, Brandon [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-14

    High energy electrons can be deflected with very tight bending radius using a bent silicon crystal. This produces gamma radiation. As these crystals can be thin, a series of bent silicon crystals with alternating direction has the potential to produce coherent gamma radiation with reasonable energy of the driving electron beam. Such an electron crystal undulator offers the prospect for higher energy radiation at lower cost than current methods. Permanent magnetic undulators like LCLS at SLAC National Accelerator Laboratory are expensive and very large (about 100 m in case of the LCLS undulator). Silicon crystals are inexpensive and compact when compared to the large magnetic undulators. Additionally, such a high energy coherent light source could be used for probing through materials currently impenetrable by x-rays. In this work we present the experimental data and analysis of experiment T523 conducted at SLAC National Accelerator Laboratory. We collected the spectrum of gamma ray emission from 14 GeV electrons on a bent silicon crystal counting single photons. We also investigated the dynamics of electron motion in the crystal i.e. processes of channeling and volume reflection at 14 GeV, extending and building off previous work. Our single photon spectrum for the amorphous crystal orientation is consistent with bremsstrahlung radiation and the volume reflection crystal orientation shows a trend consistent with synchrotron radiation at a critical energy of 740 MeV. We observe that in these two cases the data are consistent, but we make no further claims because of statistical limitations. We also extended the known energy range of electron crystal dechanneling length and channeling efficiency to 14 GeV.

  20. Observation of Multiple Volume Reflection of Ultrarelativistic Protons by a Sequence of Several Bent Silicon Crystals

    CERN Document Server

    Scandale, Walter; Baricordi, S; Dalpiaz, P; Fiorini, M; Guidi, V; Mazzolari, A; Della Mea, G; Milan, R; Ambrosi, G; Zuccon, P; Bertucci, B; Bürger, W; Duranti, M; Cavoto, G; Santacesaria, R; Valente, P; Luci, C; Iacoangeli, F; Vallazza, E; Afonin, A G; Chesnokov, Yu A; Kotov, V I; Maisheev, V A; Yazynin, I A; Kovalenko, A D; Taratin, A M; Denisov, A S; Gavrikov, Y A; Ivanov, Yu M; Lapina, L P; Malyarenko, L G; Skorogobogatov, V V; Suvorov, V M; Vavilov, S A; Bolognini, D; Hasan, S; Mozzanica, A; Prest, M

    2009-01-01

    The interactions of 400 GeV protons with different sequences of bent silicon crystals have been investigated at the H8 beam line of the CERN Super Proton Synchrotron. The multiple volume reflection of the proton beam has been studied in detail on a five-crystal reflector measuring an angular beam deflection =52.96±0.14 µrad. The efficiency was found larger than 80% for an angular acceptance at the reflector entrance of 70 µrad, with a maximal efficiency value of =0.90±0.01±0.03.

  1. Uncertainty reevaluation in determining the volume of a silicon sphere by spherical harmonics in an Avogadro project

    Institute of Scientific and Technical Information of China (English)

    Zhang Ji-Tao; Wu Xue-Jian; Li Yan

    2011-01-01

    To determine the Avogadro constant with a target relative uncertainty of 2×10-8,the uncertainty component of the silicon sphere's volume introduced by the spherical harmonics method,which is usually used in determining the sphere's volume,is reevaluated. By means of representing the shape of the silicon sphere by an ellipsoid with Gaussian white noise in its diameters,the uncertainty of the current mapping methods based on the spherical harmonics theory can be estimated theoretically. It is evidenced that the uncertainty component attributed to the current mapping method is underestimated. To eliminate this effect as much as possible,the number of mapping points should be increased to more than before. Moreover,a new mapping method is proposed to accomplish the equal-area mapping with large number points on the silicon sphere.

  2. Percent Wetland Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — Wetlands act as filters, removing or diminishing the amount of pollutants that enter surface water. Higher values for percent of wetland cover (WETLNDSPCT) may be...

  3. Percent Wetland Cover (Future)

    Data.gov (United States)

    U.S. Environmental Protection Agency — Wetlands act as filters, removing or diminishing the amount of pollutants that enter surface water. Higher values for percent of wetland cover (WETLNDSPCT) may be...

  4. The effect of metallic coatings and crystallinity on the volume expansion of silicon during electrochemical lithiation/delithiation

    KAUST Repository

    McDowell, Matthew T.

    2012-05-01

    Applying surface coatings to alloying anodes for Li-ion batteries can improve rate capability and cycle life, but it is unclear how this second phase affects mechanical deformation during electrochemical reaction. Here, in-situ transmission electron microscopy is employed to investigate the electrochemical lithiation and delithiation of silicon nanowires (NWs) with copper coatings. When copper is coated on only one sidewall, the NW bilayer structure bends during delithiation due to length changes in the silicon. Tensile hoop stress causes conformal copper coatings to fracture during lithiation without undergoing bending deformation. In addition, in-situ and ex-situ observations indicate that a copper coating plays a role in suppressing volume expansion during lithiation. Finally, the deformation characteristics and dimensional changes of amorphous, polycrystalline, and single-crystalline silicon are compared and related to observed electrochemical behavior. This study reveals important aspects of the deformation process of silicon anodes, and the results suggest that metallic coatings can be used to improve rate behavior and to manage or direct volume expansion in optimized silicon anode frameworks. © 2012 Elsevier Ltd.

  5. First observation of multiple volume reflection by different planes in one bent silicon crystal for high-energy protons

    CERN Document Server

    Scandale, E; Bagli, E; Baricordi, S; Dalpiaz, P; Fiorini, M; Guidi, V; Mazzolari, A; Vincenzi, D; Milan, R; Della Mea, Gianantonio; Vallazza, E; Afonin, A G; Chesnokov, Yu A; Maisheev, V A; Yazynin, I A; Golovatyuk, V M; Kovalenko, A D; Taratin, A M; Denisov, A S; Gavrikov, Yu A; Ivanov, Yu M; Lapina, L P; Malyarenko, L G; Skorobogatov, V V; Suvorov, V M; Vavilov, S A; Bolognini, D; Hasan, S; Mattera, A; Prest, M; Tikhomirovl, V V

    2009-01-01

    Multiple volume reflection by different planes in a bent silicon crystal with its 111 axis orientation close to the beam direction was observed for the first time for 400 GeV/c protons at the CERN SPS. The proton beam was deflected to the side opposite to the crystal bend by an angle of about 67 μrad, which is five times larger than in a single volume reflection by the (110) bent planes. The registered efficiency of one side deflection was about 84%. It was shown that multiple volume reflection transforms to a single volume reflection when the orientation angle of the 111 axis relative to the beam direction is increased

  6. A study of Channeling, Volume Reflection and Volume Capture of 3.35 - 14.0 GeV Electrons in a bent Silicon Crystal

    Energy Technology Data Exchange (ETDEWEB)

    Wistisen, T. N. [Aarhus Univ. (Denmark); Uggerhoj, U. I. [Aarhus Univ. (Denmark); Wienands, U. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Markiewicz, T. W. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Noble, R. J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Benson, B. L. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Smith, T. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Bagli, E. [Univ. of Ferrara (Italy); Bandiera, L. [Univ. of Ferrara (Italy); Germogli, G. [Univ. of Ferrara (Italy); Guidi, V. [Univ. of Ferrara (Italy); Mazzolari, A. [Univ. of Ferrara (Italy); Holtzapple, R. [California Polytechnic State Univ. (CalPoly), San Luis Obispo, CA (United States); Tucker, S. [California Polytechnic State Univ. (CalPoly), San Luis Obispo, CA (United States)

    2015-12-03

    We present the experimental data and analysis of experiments conducted at SLAC National Accelerator Laboratory investigating the processes of channeling, volume-reflection and volume-capture along the (111) plane in a strongly bent quasi-mosaic silicon crystal. Additionally, these phenomena were investigated at 5 energies: 3.35, 4.2, 6.3, 10.5 and 14.0 GeV with a crystal with bending radius of 0.15m, corresponding to curvatures of 0.070, 0.088, 0.13, 0.22 and 0.29 times the critical curvature respectively. We have extracted important parameters describing the channeling process such as the dechanneling length, the angle of volume reflection, the surface transmission and the widths of the distribution of channeled particles parallel and orthogonal to the plane.

  7. Deflection of high energy protons by multiple volume reflections in a modified multi-strip silicon deflector

    CERN Document Server

    Scandale, W; Butcher, M.; Cerutti, F.; Gilardoni, S.; Lari, L.; Lechner, A.; Losito, R.; Masi, A.; Mereghetti, A.; Metral, E.; Mirarchi, D.; Montesano, S.; Redaelli, S.; Schoofs, P.; Smirnov, G.; Bagli, E.; Bandiera, L.; Baricordi, S.; Dalpiaz, P.; Guidi, V.; Mazzolari, A.; Vincenzi, D.; Claps, G.; Dabagov, S.; Hampai, D.; Murtas, F.; Cavoto, G.; Garattini, M.; Iacoangeli, F.; Ludovici, L.; Santacesaria, R.; Valente, P.; Galluccio, F.; Afonin, A.G.; Chesnokov, Yu.A.; Maisheev, V.A.; Sandomirskiy, Yu.E.; Yanovich, A.A.; Yazynin, I.A.; Kovalenko, A.D.; Taratin, A.M.; Gavrikov, Yu.A.; Ivanov, Yu.M.; Lapina, L.P.; Ferguson, W.; Fulcher, J.; Hall, G.; Pesaresi, M.; Raymond, M.; Previtali, V.

    2014-01-01

    The effect of multiple volume reflections in one crystal was observed in each of several bent silicon strips for 400 GeV/c protons. This considerably increased the particle deflections. Some particles were also deflected due to channeling in one of the subsequent strips. As a result, the incident beam was strongly spread because of opposite directions of the deflections. A modified multi-strip deflector produced by periodic grooves on the surface of a thick silicon plate was used for these measurements. This technique provides perfect mutual alignment between crystal strips. Such multi-strip deflector may be effective for collider beam halo collimation and a study is planned at the CERN SPS circulating beam.

  8. Channeling, volume reflection and gamma emission using 14GeV electrons in bent silicon crystals - Oral presentation

    Energy Technology Data Exchange (ETDEWEB)

    Benson, Brandon [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-23

    High energy electrons can be deflected with very tight bending radius using a bent silicon crystal. This produces gamma radiation. As these crystals can be thin, a series of bent silicon crystals with alternating direction has the potential to produce coherent gamma radiation with reasonable energy of the driving electron beam. Such an electron crystal undulator offers the prospect for higher energy radiation at lower cost than current methods. Permanent magnetic undulators like LCLS at SLAC National Accelerator Laboratory are expensive and very large (about 100 m in case of the LCLS undulator). Silicon crystals are inexpensive and compact when compared to the large magnetic undulators. Additionally, such a high energy coherent light source could be used for probing through materials currently impenetrable by x-rays. In this work we present the experimental data and analysis of experiment T523 conducted at SLAC National Accelerator Laboratory. We collected the spectrum of gamma ray emission from 14 GeV electrons on a bent silicon crystal counting single photons. We also investigated the dynamics of electron motion in the crystal i.e. processes of channeling and volume reflection at 14 GeV, extending and building off previous work. Our single photon spectrum for the amorphous crystal orientation is consistent with bremsstrahlung radiation and the volume reflection crystal orientation shows a trend consistent with synchrotron radiation at a critical energy of 740 MeV. We observe that in these two cases the data are consistent, but we make no further claims because of statistical limitations. We also extended the known energy range of electron crystal dechanneling length and channeling efficiency to 14 GeV.

  9. China's imports Up 15 Percent in 2002

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Based on the latest statistical figure released from China Customs, China's total imports rose 15 percent in 2002 as compared to the previous year. The spending for China's crude oil import rose 9.4 percent to 12.757 billion yuan in 2002 while the importing volume of oil products dropped 4.9 percent to 20.34

  10. The potential for the fabrication of wires embedded in the crystalline silicon substrate using the solid phase segregation of gold in crystallising amorphous volumes

    Energy Technology Data Exchange (ETDEWEB)

    Liu, A.C.Y.; McCallum, J.C

    2004-05-15

    The refinement of gold in crystallising amorphous silicon volumes was tested as a means of creating a conducting element embedded in the crystalline matrix. Amorphous silicon volumes were created by self-ion-implantation through a mask. Five hundred kiloelectronvolt Au{sup +} was then implanted into the volumes. The amorphous volumes were crystallised on a hot stage in air, and the crystallisation was characterised using cross sectional transmission electron microscopy. It was found that the amorphous silicon volumes crystallised via solid phase epitaxy at all the lateral and vertical interfaces. The interplay of the effects of the gold and also the hydrogen that infilitrated from the surface oxide resulted in a plug of amorphous material at the surface. Further annealing at this temperature demonstrated that the gold, once it had reached a certain critical concentration nucleated poly-crystalline growth instead of solid phase epitaxy. Time resolved reflectivity and Rutherford backscattering and channeling measurements were performed on large area samples that had been subject to the same implantation regime to investigate this system further. It was discovered that the crystallisation dynamics and zone refinement of the gold were complicated functions of both gold concentration and temperature. These findings do not encourage the use of this method to obtain conducting elements embedded in the crystalline silicon substrate.

  11. Historical Evidence of Importance to the Industrialization of Flat-plate Silicon Photovoltaic Systems, Volume 2

    Science.gov (United States)

    Smith, J. L.; Gates, W. R.; Lee, T.

    1978-01-01

    Problems which may arise as the low cost silicon solar array (LSSA) project attempts to industrialize the production technologies are defined. The charge to insure an annual production capability of 500 MW peak for the photovoltaic supply industry by 1986 was critically examined, and focused on one of the motivations behind this goal-concern over the timely development of industrial capacity to supply anticipated demand. Conclusions from the analysis are utilized in a discussion of LSSA's industrialization plans, particularly the plans for pilot, demonstration and commercial scale production plants. Specific recommendations for the implementation of an industrialization task and the disposition of the project quantity goal were derived.

  12. Percents Are Not Natural Numbers

    Science.gov (United States)

    Jacobs, Jennifer A.

    2013-01-01

    Adults are prone to treating percents, one representational format of rational numbers, as novel cases of natural number. This suggests that percent values are not differentiated from natural numbers; a conceptual shift from the natural numbers to the rational numbers has not yet occurred. This is most surprising, considering people are inundated…

  13. Inspiration: One Percent and Rising

    Science.gov (United States)

    Walling, Donovan R.

    2009-01-01

    Inventor Thomas Edison once famously declared, "Genius is one percent inspiration and ninety-nine percent perspiration." If that's the case, then the students the author witnessed at the International Student Media Festival (ISMF) last November in Orlando, Florida, are geniuses and more. The students in the ISMF pre-conference workshop had much to…

  14. ROE Fish Faunal Percent Loss

    Data.gov (United States)

    U.S. Environmental Protection Agency — Percent reduction is based on the number of native species determined to be present as of 2015, compared with historical numbers documented prior to 1970. Data are...

  15. Influence of solution volume on the dissolution rate of silicon dioxide in hydrofluoric acid.

    Science.gov (United States)

    Shvartsev, Boris; Gelman, Danny; Komissarov, Ilia; Epshtein, Alon; Starosvetsky, David; Ein-Eli, Yair

    2015-02-01

    Experimental data and modeling of the dissolution of various Si/SiO2 thermal coatings in different volumes of hydrofluoric acid (HF) are reported. The rates of SiO2 -film dissolution, measured by means of various electrochemical techniques, and alteration in HF activity depend on the thickness of the film coating. Despite the small volumes (0.6-1.2 mL) of the HF solution, an effect of SiO2 -coating thickness on the dissolution rate was detected. To explain alterations detected in HF activity after SiO2 dissolution, spectroscopic analyses (NMR and FTIR) of the chemical composition of the solutions were conducted. This is associated with a modification in the chemical composition of the HF solution, which results in either the formation of an oxidized species in solution or the precipitation of dissolution products. HF2 (-) accumulation in the HF solution, owing to SiO2 dissolution was identified as the source of the chemical alteration.

  16. Autoclaved Brick from Volume-Stability-Modified Steel Slag and Low Silicon Tailings

    Directory of Open Access Journals (Sweden)

    Li Peng-guan

    2016-01-01

    Full Text Available Steel slag is a major industrial waste. Because of poor volume stability, its utilization was limited. We adopted polyphosphate modified steel slag and tailings to produce the autoclaved brick. The effects of various factors influencing the performance of brick were investigated, and the results were obtained: forming water 9%, forming pressure 20MPa, curing regime 4(temperature rising, hr-4(temperature holding at 180°C, hr-natural cooling (temperature dropping. With the content of modified steel slag in brick increased from 11% to 25%, the content of cement reduced from 7% to 5%, the compressive strength value increased from 11.6MPa to 22.1MPa.

  17. Effect of impurities and processing on silicon solar cells. Volume 1: Characterization methods for impurities in silicon and impurity effects data base

    Science.gov (United States)

    Hopkins, R. H.; Davis, J. R.; Rohatgi, A.; Campbell, R. B.; Blais, P. D.; Rai-Choudhury, P.; Stapleton, R. E.; Mollenkopf, H. C.; Mccormick, J. R.

    1980-01-01

    Two major topics are treated: methods to measure and evaluate impurity effects in silicon and comprehensive tabulations of data derived during the study. Discussions of deep level spectroscopy, detailed dark I-V measurements, recombination lifetime determination, scanned laser photo-response, conventional solar cell I-V techniques, and descriptions of silicon chemical analysis are presented and discussed. The tabulated data include lists of impurity segregation coefficients, ingot impurity analyses and estimated concentrations, typical deep level impurity spectra, photoconductive and open circuit decay lifetimes for individual metal-doped ingots, and a complete tabulation of the cell I-V characteristics of nearly 200 ingots.

  18. Percent area coverage through image analysis

    Science.gov (United States)

    Wong, Chung M.; Hong, Sung M.; Liu, De-Ling

    2016-09-01

    The notion of percent area coverage (PAC) has been used to characterize surface cleanliness levels in the spacecraft contamination control community. Due to the lack of detailed particle data, PAC has been conventionally calculated by multiplying the particle surface density in predetermined particle size bins by a set of coefficients per MIL-STD-1246C. In deriving the set of coefficients, the surface particle size distribution is assumed to follow a log-normal relation between particle density and particle size, while the cross-sectional area function is given as a combination of regular geometric shapes. For particles with irregular shapes, the cross-sectional area function cannot describe the true particle area and, therefore, may introduce error in the PAC calculation. Other errors may also be introduced by using the lognormal surface particle size distribution function that highly depends on the environmental cleanliness and cleaning process. In this paper, we present PAC measurements from silicon witness wafers that collected fallouts from a fabric material after vibration testing. PAC calculations were performed through analysis of microscope images and compare them to values derived through the MIL-STD-1246C method. Our results showed that the MIL-STD-1246C method does provide a reasonable upper bound to the PAC values determined through image analysis, in particular for PAC values below 0.1.

  19. Nanoparticle-based etching of silicon surfaces

    Science.gov (United States)

    Branz, Howard; Duda, Anna; Ginley, David S.; Yost, Vernon; Meier, Daniel; Ward, James S.

    2011-12-13

    A method (300) of texturing silicon surfaces (116) such to reduce reflectivity of a silicon wafer (110) for use in solar cells. The method (300) includes filling (330, 340) a vessel (122) with a volume of an etching solution (124) so as to cover the silicon surface 116) of a wafer or substrate (112). The etching solution (124) is made up of a catalytic nanomaterial (140) and an oxidant-etchant solution (146). The catalytic nanomaterial (140) may include gold or silver nanoparticles or noble metal nanoparticles, each of which may be a colloidal solution. The oxidant-etchant solution (146) includes an etching agent (142), such as hydrofluoric acid, and an oxidizing agent (144), such as hydrogen peroxide. Etching (350) is performed for a period of time including agitating or stirring the etching solution (124). The etch time may be selected such that the etched silicon surface (116) has a reflectivity of less than about 15 percent such as 1 to 10 percent in a 350 to 1000 nanometer wavelength range.

  20. 3D knife-edge characterization of two-photon absorption volume in silicon for integrated circuit testing.

    Science.gov (United States)

    Shao, K; Morisset, A; Pouget, V; Faraud, E; Larue, C; Lewis, D; McMorrow, D

    2011-11-01

    We have performed three-dimensional characterization of the TPA effective laser spot size in silicon using an integrated knife-edge sensor. The TPA-induced response of a CMOS integrated circuit is analyzed based on these results and compared to simulation; we have found that the charge injection capacity in IC's active layer could be influenced by irradiance energy and focus depth.

  1. The chemistry of silicon

    CERN Document Server

    Rochow, E G; Emeléus, H J; Nyholm, Ronald

    1975-01-01

    Pergamon Texts in Organic Chemistry, Volume 9: The Chemistry of Silicon presents information essential in understanding the chemical properties of silicon. The book first covers the fundamental aspects of silicon, such as its nuclear, physical, and chemical properties. The text also details the history of silicon, its occurrence and distribution, and applications. Next, the selection enumerates the compounds and complexes of silicon, along with organosilicon compounds. The text will be of great interest to chemists and chemical engineers. Other researchers working on research study involving s

  2. Mesoporous calcium–silicon xerogels with mesopore size and pore volume influence hMSC behaviors by load and sustained release of rhBMP-2

    Directory of Open Access Journals (Sweden)

    Song W

    2015-03-01

    Full Text Available Wenhua Song,1,* Xiangde Li,1,* Jun Qian,1 Guoyu Lv,2 Yonggang Yan,2 Jiacan Su,3 Jie Wei1 1Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai, People’s Republic of China; 2College of Physical Science and Technology, Sichuan University, Chengdu, People’s Republic of China; 3Changhai Hospital, Second Military Medical University, Shanghai, People’s Republic of China *These authors contributed equally to this paper Abstract: Mesoporous calcium–silicon xerogels with a pore size of 15 nm (MCS-15 and pore volume of 1.43 cm3/g were synthesized by using 1,3,5-mesitylene (TMB as the pore-expanding agent. The MCS-15 exhibited good degradability with the weight loss of 50 wt% after soaking in Tris-HCl solution for 56 days, which was higher than the 30 wt% loss shown by mesoporous calcium–silicon xerogels with a pore size of 4 nm (MCS-4. The pore size and pore volume of MCS-15 had significant influences on load and release of recombinant human bone morphogenetic protein-2 (rhBMP-2. The MCS-15 had a higher capacity to encapsulate a large amount of rhBMP-2; it could adsorb 45 mg/g of rhBMP-2 in phosphate-buffered saline after 24 hours, which was more than twice that with MCS-4 (20 mg/g. Moreover, the MCS-15 system exhibited sustained release of rhBMP-2 as compared with MCS-4 system (showing a burst release. The MCS-15/rhBMP-2 system could promote the proliferation and differentiation of human mesenchymal stem cells, showing good cytocompatibility and bioactivity. The results indicated that MCS-15, with larger mesopore size and higher pore volume, might be a promising carrier for loading and sustained release of rhBMP-2, which could be used as bone repair material with built-in osteoinduction function in bone reconstruction. Keywords: mesoporous calcium–silicon xerogels, pore size, pore volume, load-release, rhBMP-2

  3. Serial section scanning electron microscopy (S3EM on silicon wafers for ultra-structural volume imaging of cells and tissues.

    Directory of Open Access Journals (Sweden)

    Heinz Horstmann

    Full Text Available High resolution, three-dimensional (3D representations of cellular ultrastructure are essential for structure function studies in all areas of cell biology. While limited subcellular volumes have been routinely examined using serial section transmission electron microscopy (ssTEM, complete ultrastructural reconstructions of large volumes, entire cells or even tissue are difficult to achieve using ssTEM. Here, we introduce a novel approach combining serial sectioning of tissue with scanning electron microscopy (SEM using a conductive silicon wafer as a support. Ribbons containing hundreds of 35 nm thick sections can be generated and imaged on the wafer at a lateral pixel resolution of 3.7 nm by recording the backscattered electrons with the in-lens detector of the SEM. The resulting electron micrographs are qualitatively comparable to those obtained by conventional TEM. S(3EM images of the same region of interest in consecutive sections can be used for 3D reconstructions of large structures. We demonstrate the potential of this approach by reconstructing a 31.7 µm(3 volume of a calyx of Held presynaptic terminal. The approach introduced here, Serial Section SEM (S(3EM, for the first time provides the possibility to obtain 3D ultrastructure of large volumes with high resolution and to selectively and repetitively home in on structures of interest. S(3EM accelerates process duration, is amenable to full automation and can be implemented with standard instrumentation.

  4. The Algebra of the Cumulative Percent Operation.

    Science.gov (United States)

    Berry, Andrew J.

    2002-01-01

    Discusses how to help students avoid some pervasive reasoning errors in solving cumulative percent problems. Discusses the meaning of ."%+b%." the additive inverse of ."%." and other useful applications. Emphasizes the operational aspect of the cumulative percent concept. (KHR)

  5. Alzheimer's Deaths Jump 55 Percent: CDC

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_165941.html Alzheimer's Deaths Jump 55 Percent: CDC More patients also ... News) -- As more baby boomers age, deaths from Alzheimer's disease have jumped 55 percent, and in a ...

  6. Mesoporous calcium-silicon xerogels with mesopore size and pore volume influence hMSC behaviors by load and sustained release of rhBMP-2.

    Science.gov (United States)

    Song, Wenhua; Li, Xiangde; Qian, Jun; Lv, Guoyu; Yan, Yonggang; Su, Jiacan; Wei, Jie

    2015-01-01

    Mesoporous calcium-silicon xerogels with a pore size of 15 nm (MCS-15) and pore volume of 1.43 cm(3)/g were synthesized by using 1,3,5-mesitylene (TMB) as the pore-expanding agent. The MCS-15 exhibited good degradability with the weight loss of 50 wt% after soaking in Tris-HCl solution for 56 days, which was higher than the 30 wt% loss shown by mesoporous calcium-silicon xerogels with a pore size of 4 nm (MCS-4). The pore size and pore volume of MCS-15 had significant influences on load and release of recombinant human bone morphogenetic protein-2 (rhBMP-2). The MCS-15 had a higher capacity to encapsulate a large amount of rhBMP-2; it could adsorb 45 mg/g of rhBMP-2 in phosphate-buffered saline after 24 hours, which was more than twice that with MCS-4 (20 mg/g). Moreover, the MCS-15 system exhibited sustained release of rhBMP-2 as compared with MCS-4 system (showing a burst release). The MCS-15/rhBMP-2 system could promote the proliferation and differentiation of human mesenchymal stem cells, showing good cytocompatibility and bioactivity. The results indicated that MCS-15, with larger mesopore size and higher pore volume, might be a promising carrier for loading and sustained release of rhBMP-2, which could be used as bone repair material with built-in osteoinduction function in bone reconstruction.

  7. High Volume Manufacturing of Silicon-Film Solar Cells and Modules; Final Subcontract Report, 26 February 2003 - 30 September 2003

    Energy Technology Data Exchange (ETDEWEB)

    Rand, J. A.; Culik, J. S.

    2005-10-01

    The objective of the PV Manufacturing R&D subcontract was to continue to improve AstroPower's technology for manufacturing Silicon-Film* wafers, solar cells, and modules to reduce costs, and increase production yield, throughput, and capacity. As part of the effort, new technology such as the continuous back metallization screen-printing system and the laser scribing system were developed and implemented. Existing processes, such as the silicon nitride antireflection coating system and the fire-through process were optimized. Improvements were made to the statistical process control (SPC) systems of the major manufacturing processes: feedstock preparation, wafer growth, surface etch, diffusion, and the antireflection coating process. These process improvements and improved process control have led to an increase of 5% relative power, and nearly 15% relative improvement in mechanical and visual yield.

  8. Low cost silicon solar array project silicon materials task: Establishment of the feasibility of a process capable of low-cost, high volume production of silane (step 1) and the pyrolysis of silane to semiconductor-grade silicon (step 2)

    Science.gov (United States)

    Breneman, W. C.; Cheung, H.; Farrier, E. G.; Morihara, H.

    1977-01-01

    A quartz fluid bed reactor capable of operating at temperatures of up to 1000 C was designed, constructed, and successfully operated. During a 30 minute experiment, silane was decomposed within the reactor with no pyrolysis occurring on the reactor wall or on the gas injection system. A hammer mill/roller-crusher system appeared to be the most practical method for producing seed material from bulk silicon. No measurable impurities were detected in the silicon powder produced by the free space reactor, using the cathode layer emission spectroscopic technique. Impurity concentration followed by emission spectroscopic examination of the residue indicated a total impurity level of 2 micrograms/gram. A pellet cast from this powder had an electrical resistivity of 35 to 45 ohm-cm and P-type conductivity.

  9. Historical evidence of importance to the industrialization of flat-plate silicon photovoltaic systems. Volume 1: Executive summary

    Science.gov (United States)

    Smith, J. L.

    1978-01-01

    An analysis is given of the Low-Cost Silicon Solar Array Project plans for the industrialization of new production technologies expected to be forthcoming as a result of the project's technology development efforts. In particular, LSSA's mandate to insure an annual production capability of 500 MW peak for the photovoltaic supply industry by 1986 is critically examined. The examination focuses on one of the concerns behind this goal -- timely development of industrial capacity to supply anticipated demand. Some of the conclusions include: (1) construction of small-scale pilot plants should be undertaken only for purposes of technology development; (2) large-scale demonstrations should be undertaken only when the technology is well in hand; (3) commercial-scale production should be left to the private sector; (4) the 500-MW annual output goal should be shifted to Program Headquarters.

  10. Silicon processing for photovoltaics II

    CERN Document Server

    Khattak, CP

    2012-01-01

    The processing of semiconductor silicon for manufacturing low cost photovoltaic products has been a field of increasing activity over the past decade and a number of papers have been published in the technical literature. This volume presents comprehensive, in-depth reviews on some of the key technologies developed for processing silicon for photovoltaic applications. It is complementary to Volume 5 in this series and together they provide the only collection of reviews in silicon photovoltaics available.The volume contains papers on: the effect of introducing grain boundaries in silicon; the

  11. Transformational silicon electronics

    KAUST Repository

    Rojas, Jhonathan Prieto

    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. © 2014 American Chemical Society.

  12. Estimating a percent reduction in load

    Science.gov (United States)

    Millard, Steven P.

    This article extends the work of Cohn et al. [1989] on estimating constituent loads to the problem of estimating a percent reduction in load. Three estimators are considered: the maximum likelihood (MLE), a ``bias-corrected'' maximum likelihood (BCMLE), and the minimum variance unbiased (MVUE). In terms of root-mean-square error, both the MVUE and BCMLE are superior to the MLE, and for the cases considered here there is no appreciable difference between the MVUE and the BCMLE. The BCMLE is constructed from quantities computed by most regression packages and is therefore simpler to compute than the MVUE (which involves approximating an infinite series). All three estimators are applied to a case study in which an agricultural tax in the Everglades agricultural area is tied to an observed percent reduction in phosphorus load. For typical hydrological data, very large sample sizes (of the order of 100 observations each in the baseline period and after) are required to estimate a percent reduction in load with reasonable precision.

  13. How I Love My 80 Percenters

    Science.gov (United States)

    Maturo, Anthony J.

    2002-01-01

    Don't ever take your support staff for granted. By support staff, I mean the people in personnel, logistics, and finance; the ones who can make things happen with a phone call or a signature, or by the same token frustrate you to no end by their inaction; these are people you must depend on. I've spent a lot of time thinking about how to cultivate relationships with my support staff that work to the advantage of both of us. The most important thing that have learned working with people, any people--and I will tell you how I learned this in a minute--is there are some folks you just can't motivate, so forget it, don't try; others you certainly can with a little psychology and some effort; and the best of the bunch, what I call the 80 percenters, you don't need to motivate because they're already on the team and performing beautifully. The ones you can't change are rocks. Face up to it, and just kick them out of your way. I have a reputation with the people who don't want to perform or be part of the team. They don't come near me. If someone's a rock, I pick up on it right away, and I will walk around him or her to find someone better. The ones who can be motivated I take time to nurture. I consider them my projects. A lot of times these wannabes are people who want to help but don't know how. Listen, you can work with them. Lots of people in organizations have the mindset that all that matters are the regulations. God forbid if you ever work outside those regulations. They've got one foot on that regulation and they're holding it tight like a baby holds a blanket. What you're looking for is that first sign that their minds are opening. Usually you hear it in their vocabulary. What used to sound like "We can't do that ... the regulations won't allow it ... we have never done this before," well, suddenly that changes to "We have options ... let's take a look at the options ... let me research this and get back to you." The 80 percenters you want to nurture too, but

  14. Diffusivity in silicon 1953 to 2009

    CERN Document Server

    Fisher, David J

    2010-01-01

    This work is essentially an update of previous compilations of information on the diffusivity of elements in semiconductor-grade silicon. It subsumes the data contained in B.L.Sharma's monograph on 'Diffusion in Semiconductors' (Trans Tech Publications, 1970), plus the data contained in Diffusion and Defect Data (Diffusion in Silicon) Volume 45 (1986), Defect and Diffusion Forum (Diffusion in Silicon - 10 years of Research) Volumes 153-155 (1998), Defect and Diffusion Forum (Diffusion in Silicon - a Seven-Year Retrospective) Volume 241 (2005) and the latest data from recent Semiconductor Retro

  15. Roadmap on silicon photonics

    Science.gov (United States)

    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

  16. The Future of Silicon Valley

    Institute of Scientific and Technical Information of China (English)

    Joseph Leu

    2006-01-01

    @@ By the end of 1984, Silicon Valley was going through the down cycle fol lowing the PC boom. A hundred PC companies wanted just 10 percent of the market, wanting to strike it rich, as rich as the Apple IPO (Initial Public Of fering) -the Google celebrity IPO of its day.

  17. The Silicon Cube detector

    Energy Technology Data Exchange (ETDEWEB)

    Matea, I.; Adimi, N. [Centre d' Etudes Nucleaires de Bordeaux Gradignan - Universite Bordeaux 1 - UMR 5797, CNRS/IN2P3, Chemin du Solarium, BP 120, F-33175 Gradignan Cedex (France); Blank, B. [Centre d' Etudes Nucleaires de Bordeaux Gradignan - Universite Bordeaux 1 - UMR 5797, CNRS/IN2P3, Chemin du Solarium, BP 120, F-33175 Gradignan Cedex (France)], E-mail: blank@cenbg.in2p3.fr; Canchel, G.; Giovinazzo, J. [Centre d' Etudes Nucleaires de Bordeaux Gradignan - Universite Bordeaux 1 - UMR 5797, CNRS/IN2P3, Chemin du Solarium, BP 120, F-33175 Gradignan Cedex (France); Borge, M.J.G.; Dominguez-Reyes, R.; Tengblad, O. [Insto. Estructura de la Materia, CSIC, Serrano 113bis, E-28006 Madrid (Spain); Thomas, J.-C. [GANIL, CEA/DSM - CNRS/IN2P3, BP 55027, F-14076 Caen Cedex 5 (France)

    2009-08-21

    A new experimental device, the Silicon Cube detector, consisting of six double-sided silicon strip detectors placed in a compact geometry was developed at CENBG. Having a very good angular coverage and high granularity, it allows simultaneous measurements of energy and angular distributions of charged particles emitted from unbound nuclear states. In addition, large-volume Germanium detectors can be placed close to the collection point of the radioactive species to be studied. The setup is ideally suited for isotope separation on-line (ISOL)-type experiments to study multi-particle emitters and was tested during an experiment at the low-energy beam line of SPIRAL at GANIL.

  18. Low cost silicon-on-ceramic photovoltaic solar cells

    Science.gov (United States)

    Koepke, B. G.; Heaps, J. D.; Grung, B. L.; Zook, J. D.; Sibold, J. D.; Leipold, M. H.

    1980-01-01

    A technique has been developed for coating low-cost mullite-based refractory substrates with thin layers of solar cell quality silicon. The technique involves first carbonizing one surface of the ceramic and then contacting it with molten silicon. The silicon wets the carbonized surface and, under the proper thermal conditions, solidifies as a large-grained sheet. Solar cells produced from this composite silicon-on-ceramic material have exhibited total area conversion efficiencies of ten percent.

  19. Silicon materials task of the low cost solar array project (Phase III). Effect of impurities and processing on silicon solar cells. Phase III summary and seventeenth quarterly report, Volume 1: characterization methods for impurities in silicon and impurity effects data base

    Energy Technology Data Exchange (ETDEWEB)

    Hopkins, R.H.; Davis, J.R.; Rohatgi, A.; Campbell, R.B.; Blais, P.D.; Rai-Choudhury, P.; Stapleton, R.E.; Mollenkopf, H.C.; McCormick, J.R.

    1980-01-01

    The object of Phase III of the program has been to investigate the effects of various processes, metal contaminants and contaminant-process interactions on the performance of terrestrial silicon solar cells. The study encompassed a variety of tasks including: (1) a detailed examination of thermal processing effects, such as HCl and POCl/sub 3/ gettering on impurity behavior, (2) completion of the data base and modeling for impurities in n-base silicon, (3) extension of the data base on p-type material to include elements likely to be introduced during the production, refining, or crystal growth of silicon, (4) effects on cell performance on anisotropic impurity distributions in large CZ crystals and silicon webs, and (5) a preliminary assessment of the permanence of the impurity effects. Two major topics are treated: methods to measure and evaluate impurity effects in silicon and comprehensive tabulations of data derived during the study. For example, discussions of deep level spectroscopy, detailed dark I-V measurements, recombination lifetime determination, scanned laser photo-response, and conventional solar cell I-V techniques, as well as descriptions of silicon chemical analysis are included. Considerable data are tabulated on the composition, electrical, and solar cell characteristics of impurity-doped silicon.

  20. Guidance on Compatibility of UST Systems with Ethanol Blends Greater Than 10 Percent and Biodiesel Blends Greater Than 20 Percent

    Science.gov (United States)

    EPA guidance on complying with the federal compatibility requirement for underground storage tank (UST) systems storing gasoline containing greater than 10 percent ethanol or diesel containing greater than 20 percent biodiesel.

  1. Effects of covert subject actions on percent body fat by air-displacement plethsymography.

    Science.gov (United States)

    Tegenkamp, Michelle H; Clark, R Randall; Schoeller, Dale A; Landry, Greg L

    2011-07-01

    Air-displacement plethysmography (ADP) is used for estimation of body composition, however, some individuals, such as athletes in weight classification sports, may use covert methods during ADP testing to alter their apparent percent body fat. The purpose of this study was to examine the effect of covert subject actions on percent body fat measured by ADP. Subjects underwent body composition analysis in the Bod Pod following the standard procedure using the manufacturer's guidelines. The subjects then underwent 8 more measurements while performing the following intentional manipulations: 4 breathing patterns altering lung volume, foot movement to disrupt air, hand cupping to trap air, and heat and cold exposure before entering the chamber. Increasing and decreasing lung volume during thoracic volume measurement and during body density measurement altered the percent body fat assessment (p < 0.001). High lung volume during thoracic gas measures overestimated fat by 3.7 ± 2.1 percentage points. Lowered lung volume during body volume measures overestimated body fat by an additional 2.2 ± 2.1 percentage points. The heat and cold exposure, tapping, and cupping treatments provided similar estimates of percent body fat when compared with the standard condition. These results demonstrate the subjects were able to covertly change their estimated ADP body composition value by altering breathing when compared with the standard condition. We recommend that sports conditioning coaches, athletic trainers, and technicians administering ADP should be aware of the potential effects of these covert actions. The individual responsible for administering ADP should remain vigilant during testing to detect deliberate altered breathing patterns by athletes in an effort to gain a competitive advantage by manipulating their body composition assessment.

  2. Silicon spintronics.

    Science.gov (United States)

    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.

  3. Mechanical behavior of the directionally solidified. gamma. /. gamma. '--delta eutectic alloy. [Ni-20. 0 percent Nb-2. 5 percent Al-6. 0 percent Cr

    Energy Technology Data Exchange (ETDEWEB)

    Barkalow, R.H.; Jackson, J.J.; Gell, M.; Leverant, G.R.

    1975-01-01

    The eutectic alloy Ni-20.0 percent Nb-2.5 percent Al-6.0 percent Cr was tested in short-term creep and long-term exposure to service conditions to assess its suitability for high temperature turbine blade applications. Long-time exposure showed the lamellar microstructure of the alloy to be exceptionally stable. Other properties tested were notch sensitivity, isothermal and thermomechanical fatigue strength, shear strength, and transverse ductility. It was shown that this alloy is superior to the best currently available directionally solidified superalloys over the temperature/stress conditions encountered in turbine airfoils.

  4. Enamel, Silicone Alkyd Copolymer (Metric)

    Science.gov (United States)

    2007-11-02

    shall consist of a copolymerized, air- drying, silicone modified long oil soya alkyd conforming to the requirements of table IV (see table VI...anhydride, percent by weight of nonvolatile vehicle Drying oil acids, percent by weight of nonvolatile vehicle Soya oil Rosin Phenolic resin...FED-STD-141 method Test Drying time 1/ Table V 4.6.17 Accelerated weathering 3.5.13 4061.2 D 523, D 569, D 2244, E 97, G 53 4.6.18 Soya

  5. CRED Cumulative Map of Percent Scleractinian Coral Cover at Zealandia

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  6. CRED Cumulative Map of Percent Scleractinian Coral Cover at Maug

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  7. CRED Cumulative Map of Percent Scleractinian Coral Cover at Tutuila

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  8. CRED Cumulative Map of Percent Scleractinian Coral Cover at Guguan

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  9. CRED Cumulative Map of Percent Scleractinian Coral Cover at Arakane

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  10. CRED Cumulative Map of Percent Scleractinian Coral Cover at Saipan

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  11. CRED Cumulative Map of Percent Scleractinian Coral Cover at Sarigan

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  12. CRED Cumulative Map of Percent Scleractinian Coral Cover at Agrihan

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  13. CRED Cumulative Map of Percent Scleractinian Coral Cover at Anatahan

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  14. Characterization of the uranium--2 weight percent molybdenum alloy. [Treatment to obtain 930 MPa yield strength (0. 2 percent)

    Energy Technology Data Exchange (ETDEWEB)

    Hemperly, V.C.

    1976-05-19

    The uranium-2 wt percent molybdenum alloy was prepared, processed, and age hardened to meet a minimum 930-MPa yield strength (0.2 percent) with a minimum of 10 percent elongation. These mechanical properties were obtained with a carbon level up to 300 ppM in the alloy. The tensile-test ductility is lowered by the humidity of the laboratory atmosphere. (auth)

  15. The Texas Ten Percent Plan's Impact on College Enrollment

    Science.gov (United States)

    Daugherty, Lindsay; Martorell, Paco; McFarlin, Isaac, Jr.

    2014-01-01

    The Texas Ten Percent Plan (TTP) provides students in the top 10 percent of their high-school class with automatic admission to any public university in the state, including the two flagship schools, the University of Texas at Austin and Texas A&M. Texas created the policy in 1997 after a federal appellate court ruled that the state's previous…

  16. The Texas Ten Percent Plan's Impact on College Enrollment

    Science.gov (United States)

    Daugherty, Lindsay; Martorell, Paco; McFarlin, Isaac, Jr.

    2014-01-01

    The Texas Ten Percent Plan (TTP) provides students in the top 10 percent of their high-school class with automatic admission to any public university in the state, including the two flagship schools, the University of Texas at Austin and Texas A&M. Texas created the policy in 1997 after a federal appellate court ruled that the state's previous…

  17. Decoupling crystalline volume fraction and V{sub OC} in microcrystalline silicon pin solar cells by using a {mu}c-Si:F:H intrinsic layer

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Q.; Johnson, E.V.; Djeridane, Y.; Abramov, A.; Roca i Cabarrocas, P. [LPICM-CNRS, Ecole Polytechnique, Palaiseau (France)

    2008-08-15

    Microcrystalline silicon thin film pin solar cells with a highly crystallized intrinsic {mu}c-Si:F:H absorber were prepared by RF-plasma enhanced chemical vapour deposition using SiF{sub 4} as the gas precursor. The cells were produced with a vacuum break between the doped layer and intrinsic layer depositions, and the effect of different subsequent interface treatment processes was studied. The use of an intrinsic {mu}c-Si:H p/i buffer layer before the first air break increased the short circuit current density from 22.3 mA/cm{sup 2} to 24.7 mA/cm{sup 2}. However, the use of a hydrogen-plasma treatment after both air breaks without an interface buffer layer improved both the open circuit voltage and the fill factor. Although the material used for the absorber layer showed a very high crystalline fraction and thus an increased spectral response at long wavelengths, an open-circuit voltage (V{sub OC}) of 0.523 V was nevertheless observed. Such a value of V{sub OC} is higher than is typically obtained in devices that employ a highly crystallized absorber as reported in the literature (see abstract figure). Using a hydrogen-plasma treatment, a single junction {mu}c-Si:F:H pin solar cell with an efficiency of 8.3% was achieved. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Mesoporous Silicon-Based Anodes

    Science.gov (United States)

    Peramunage, Dharmasena

    2015-01-01

    For high-capacity, high-performance lithium-ion batteries. A new high-capacity anode composite based on mesoporous silicon is being developed. With a structure that resembles a pseudo one-dimensional phase, the active anode material will accommodate significant volume changes expected upon alloying and dealloying with lithium (Li).

  19. Electron beam silicon purification

    Energy Technology Data Exchange (ETDEWEB)

    Kravtsov, Anatoly [SIA ' ' KEPP EU' ' , Riga (Latvia); Kravtsov, Alexey [' ' KEPP-service' ' Ltd., Moscow (Russian Federation)

    2014-11-15

    Purification of heavily doped electronic grade silicon by evaporation of N-type impurities with electron beam heating was investigated in process with a batch weight up to 50 kilos. Effective temperature of the melt, an indicative parameter suitable for purification process characterization was calculated and appeared to be stable for different load weight processes. Purified material was successfully approbated in standard CZ processes of three different companies. Each company used its standard process and obtained CZ monocrystals applicable for photovoltaic application. These facts enable process to be successfully scaled up to commercial volumes (150-300 kg) and yield solar grade silicon. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Silicon Nitride Antireflection Coatings for Photovoltaic Cells

    Science.gov (United States)

    Johnson, C.; Wydeven, T.; Donohoe, K.

    1984-01-01

    Chemical-vapor deposition adapted to yield graded index of refraction. Silicon nitride deposited in layers, refractive index of which decreases with distance away from cell/coating interface. Changing index of refraction allows adjustment of spectral transmittance for wavelengths which cell is most effective at converting light to electric current. Average conversion efficiency of solar cells increased from 8.84 percent to 12.63 percent.

  1. Thermal-shock Resistance of a Ceramic Comprising 60 Percent Boron Carbide and 40 Percent Titanium Diboride

    Science.gov (United States)

    Yeomans, C M; Hoffman, C A

    1953-01-01

    Thermal-shock resistance of a ceramic comprising 60 percent boron carbide and 40 percent titanium diboride was investigated. The material has thermal shock resistance comparable to that of NBS body 4811C and that of zirconia, but is inferior to beryllia, alumina, and titanium-carbide ceramals. It is not considered suitable for turbine blades.

  2. Electroless porous silicon formation applied to fabrication of boron-silica-glass cantilevers

    DEFF Research Database (Denmark)

    Teva, Jordi; Davis, Zachary James; Hansen, Ole

    2010-01-01

    This work describes the characterization and optimization of anisotropic formation of porous silicon in large volumes (0.5-1 mm3) of silicon by an electroless wet etching technique. The main goal is to use porous silicon as a sacrificial volume for bulk micromachining processes, especially in cases...

  3. A simple model to predict the biodiesel blend density as simultaneous function of blend percent and temperature.

    Science.gov (United States)

    Gaonkar, Narayan; Vaidya, R G

    2016-05-01

    A simple method to estimate the density of biodiesel blend as simultaneous function of temperature and volume percent of biodiesel is proposed. Employing the Kay's mixing rule, we developed a model and investigated theoretically the density of different vegetable oil biodiesel blends as a simultaneous function of temperature and volume percent of biodiesel. Key advantage of the proposed model is that it requires only a single set of density values of components of biodiesel blends at any two different temperatures. We notice that the density of blend linearly decreases with increase in temperature and increases with increase in volume percent of the biodiesel. The lower values of standard estimate of error (SEE = 0.0003-0.0022) and absolute average deviation (AAD = 0.03-0.15 %) obtained using the proposed model indicate the predictive capability. The predicted values found good agreement with the recent available experimental data.

  4. Analysis of Percent Elongation for Ductile Metal in Uniaxial Tension

    Institute of Scientific and Technical Information of China (English)

    WANG Xue-bin; YANG Mei; JIANG Jian

    2005-01-01

    Percent elongation of ductile metal in uniaxial tension due to non-homogeneity was analyzed based on gradient-dependent plasticity. Three assumptions are used to get the analytical solution of percent elongation: one is static equilibrium condition in axial direction; another is that plastic volumetric strain is zero in necking zone;the other is that the diameter in unloading zone remains constant after strain localization is initiated. The strain gradient term was introduced into the yield function of classical plastic mechanics to obtain the analytical solution of distributed plastic strain. Integrating the plastic strain and considering the influence of necking on plastic elongation, a one-dimensional analytical solution of percent elongation was proposed. The analytical solution shows that the percent elongation is inversely proportional to the gauge length, and the solution is formally similar to earlier empirical formula proposed by Barba. Comparisons of existing experimental results and present analytical solutions for relation between load and total elongation and for relation between percent elongation and gauge lengthwere carried out and the new mechanical model for percent elongation was verified. Moreover, higher ductility,toughness and heterogeneity can cause much larger percentage elongation, which coincides with usual viewpoints.

  5. Silicon Spintronics

    NARCIS (Netherlands)

    Jansen, R.

    2008-01-01

    Integration of magnetism and mainstream semiconductor electronics could impact information technology in ways beyond imagination. A pivotal step is implementation of spin-based electronic functionality in silicon devices. Remarkable progress made during the last two years gives confidence that this

  6. Synthesis of Silicon Nanocrystals in Microplasma Reactor

    Science.gov (United States)

    Nozaki, Tomohiro; Sasaki, Kenji; Ogino, Tomohisa; Asahi, Daisuke; Okazaki, Ken

    Nanocrystalline silicon particles with a grain size of at least less than 10 nm are widely recognized as one of the key materials in optoelectronic devices, electrodes of lithium battery, bio-medical labels. There is also important character that silicon is safe material to the environment and easily gets involved in existing silicon technologies. To date, several synthesis methods such as sputtering, laser ablation, and plasma enhanced chemical vapor deposition (PECVD) based on low-pressure silane chemistry (SiH4) have been developed for precise control of size and density distributions of silicon nanocrystals. We explore the possibility of microplasma technologies for the efficient production of mono-dispersed nanocrystalline silicon particles in a micrometer-scale, continuous-flow plasma reactor operated at atmospheric pressure. Mixtures of argon, hydrogen, and silicon tetrachloride were activated using very high frequency (VHF = 144 MHz) power source in a capillary glass tube with a volume of less than 1 μ-liter. Fundamental plasma parameters of VHF capacitively coupled microplasma were characterized by optical emission spectroscopy, showing electron density of approximately 1015 cm-3 and rotational temperature of 1500 K, respectively. Such high-density non-thermal reactive plasma has a capability of decomposing silicon tetrachloride into atomic silicon to produce supersaturated atomic silicon vapor, followed by gas phase nucleation via three-body collision. The particle synthesis in high-density plasma media is beneficial for promoting nucleation process. In addition, further growth of silicon nuclei was able to be favorably terminated in a short-residence time reactor. Micro Raman scattering spectrum showed that as-deposited particles were mostly amorphous silicon with small fraction of silicon nanocrystals. Transmission electron micrograph confirmed individual silicon nanocrystals of 3-15 nm size. Although those particles were not mono-dispersed, they were

  7. Silicon Nanocrystal Synthesis in Microplasma Reactor

    Science.gov (United States)

    Nozaki, Tomohiro; Sasaki, Kenji; Ogino, Tomohisa; Asahi, Daisuke; Okazaki, Ken

    Nanocrystalline silicon particles with grains smaller than 5 nm are widely recognized as a key material in optoelectronic devices, lithium battery electrodes, and bio-medical labels. Another important characteristic is that silicon is an environmentally safe material that is used in numerous silicon technologies. To date, several synthesis methods such as sputtering, laser ablation, and plasma-enhanced chemical vapor deposition (PECVD) based on low-pressure silane chemistry (SiH4) have been developed for precise control of size and density distributions of silicon nanocrystals. In this study, we explore the possibility of microplasma technologies for efficient production of mono-dispersed nanocrystalline silicon particles on a micrometer-scale, continuous-flow plasma reactor operated at atmospheric pressure. Mixtures of argon, hydrogen, and silicon tetrachloride were activated using a very-high-frequency (144 MHz) power source in a capillary glass tube with volume of less than 1 μl. Fundamental plasma parameters of the microplasma were characterized using optical emission spectroscopy, which respectively indicated electron density of 1015 cm-3, argon excitation temperature of 5000 K, and rotational temperature of 1500 K. Such high-density non-thermal reactive plasma can decompose silicon tetrachloride into atomic silicon to produce supersaturated silicon vapor, followed by gas-phase nucleation via three-body collision: particle synthesis in high-density plasma media is beneficial for promoting nucleation processes. In addition, further growth of silicon nuclei can be terminated in a short-residence-time reactor. Micro-Raman scattering spectra showed that as-deposited particles are mostly amorphous silicon with a small fraction of silicon nanocrystals. Transmission electron micrography confirmed individual 3-15 nm silicon nanocrystals. Although particles were not mono-dispersed, they were well separated and not coagulated.

  8. Lithographically patterned silicon nanostructures on silicon substrates

    Energy Technology Data Exchange (ETDEWEB)

    Megouda, Nacera [Institut de Recherche Interdisciplinaire (IRI, USR 3078), Universite Lille1, Parc de la Haute Borne, 50 Avenue de Halley-BP 70478, 59658 Villeneuve d' Ascq and Institut d' Electronique, de Microelectronique et de Nanotechnologie (IEMN, CNRS-8520), Cite Scientifique, Avenue Poincare-B.P. 60069, 59652 Villeneuve d' Ascq (France); Faculte des Sciences, Universite Mouloud Mammeri, Tizi-Ouzou (Algeria); Unite de Developpement de la Technologie du Silicium (UDTS), 2 Bd. Frantz Fanon, B.P. 140 Alger-7 merveilles, Alger (Algeria); Piret, Gaeelle; Galopin, Elisabeth; Coffinier, Yannick [Institut de Recherche Interdisciplinaire (IRI, USR 3078), Universite Lille1, Parc de la Haute Borne, 50 Avenue de Halley-BP 70478, 59658 Villeneuve d' Ascq and Institut d' Electronique, de Microelectronique et de Nanotechnologie (IEMN, CNRS-8520), Cite Scientifique, Avenue Poincare-B.P. 60069, 59652 Villeneuve d' Ascq (France); Hadjersi, Toufik, E-mail: hadjersi@yahoo.com [Unite de Developpement de la Technologie du Silicium (UDTS), 2 Bd. Frantz Fanon, B.P. 140 Alger-7 merveilles, Alger (Algeria); Elkechai, Omar [Faculte des Sciences, Universite Mouloud Mammeri, Tizi-Ouzou (Algeria); and others

    2012-06-01

    The paper reports on controlled formation of silicon nanostructures patterns by the combination of optical lithography and metal-assisted chemical dissolution of crystalline silicon. First, a 20 nm-thick gold film was deposited onto hydrogen-terminated silicon substrate by thermal evaporation. Gold patterns (50 {mu}m Multiplication-Sign 50 {mu}m spaced by 20 {mu}m) were transferred onto the silicon wafer by means of photolithography. The etching process of crystalline silicon in HF/AgNO{sub 3} aqueous solution was studied as a function of the silicon resistivity, etching time and temperature. Controlled formation of silicon nanowire arrays in the unprotected areas was demonstrated for highly resistive silicon substrate, while silicon etching was observed on both gold protected and unprotected areas for moderately doped silicon. The resulting layers were characterized using scanning electron microscopy (SEM).

  9. Percent body fat, fractures and risk of osteoporosis in women.

    Science.gov (United States)

    Wyshak, G

    2010-06-01

    Globally, in an aging population, osteoporosis and fractures are emerging as major public health problems; accessible and affordable recognition, prevention and treatment strategies are needed. Percent body fat is known to be associated with bone mineral density and fractures. This paper uses an innovative, virtually cost-free method to estimate percent body fat from age, height and weight, and assesses its validity by examining the association between percent body fat and fractures among women 39 and older. An epidemiologic study. 3940 college alumnae, median age 53.6, participated by responding to a mailed questionnaire covering medical history, behavioral factors, birth date, weight and height. T-tests, chi-square and multivariable logistic regression. Percent body fat estimated from age, weight, height and gender. Associations of fractures with percent body fat are expressed as odds ratios: for osteoporotic (wrist, hip and/or x-ray confirmed vertebral), the adjusted OR = 2.41, 95% CI (1.65, 3.54), P age, height and weight may be a valid, cost-saving, and cost-effective alternative tool for screening and assessing risk of osteoporosis in settings where Dual x-ray absorptiometry (DXA) or other radiological techniques are too costly or unavailable.

  10. Device Architecture Simplification of Laser Pattering in High-Volume Crystalline Silicon Solar Cell Fabrication using Intensive Computation for Design and Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Grupp Mueller, Guenther [SolarWorld Industries America, Hillsboro, OR (United States); Herfurth, Hans [Fraunhofer Center for Laser Technology (FhCLT), Plymouth, MI (United States); Dunham, Scott [Univ. of Washington, Seattle, WA (United States); Xu, Baomin [PARC (Palo Alto Research Center), Palo Alto, CA (United States)

    2013-11-15

    Prices of Si based solar modules have been continuously declining in recent years. Goodrich is pointing out that a significant portion of these cost reductions have come about due to ‘economies of scale’ benefits, but there is a point of diminishing returns when trying to lower cost by simply expanding production capacity. Developing innovative high volume production technologies resulting in an increase of conversion efficiency without adding significant production cost will be necessary to continue the projected cost reductions. The Foundational Program to Advance Cell Efficiency (FPACE) is seeking to achieve this by closing the PV efficiency gap between theoretical achievable maximum conversion efficiency - 29% for c-Si - and the current typical production - 18.5% for a typical full area back contact c-Si Solar cell – while targeting a module cost of $0.50/Watt . The research conducted by SolarWorldUSA and it’s partners within the FPACE framework focused on the development of a Hybrid metal-wrap-through (MWT) and laser-ablated PERC solar cell design employing a extrusion metallization scheme to achieve >20% efficient devices. The project team was able to simulate, develop and demonstrate the technologies necessary to build p-type MWT PERC cells with extruded front contacts. Conversion efficiencies approaching 20% were demonstrated and a path for further efficiency improvements identified. A detailed cost of ownership calculation for such a device was based on a NREL cost model and is predicting a $/Watt cost below 85 cents on a 180 micron substrate.

  11. Germanium silicon physics and materials

    CERN Document Server

    Willardson, R K; Bean, John C; Hull, Robert

    1998-01-01

    Since its inception in 1966, the series of numbered volumes known as Semiconductors and Semimetals has distinguished itself through the careful selection of well-known authors, editors, and contributors. The "Willardson and Beer" Series, as it is widely known, has succeeded in publishing numerous landmark volumes and chapters. Not only did many of these volumes make an impact at the time of their publication, but they continue to be well-cited years after their original release. Recently, Professor Eicke R. Weber of the University of California at Berkeley joined as a co-editor of the series. Professor Weber, a well-known expert in the field of semiconductor materials, will further contribute to continuing the series' tradition of publishing timely, highly relevant, and long-impacting volumes. Some of the recent volumes, such as Hydrogen in Semiconductors, Imperfections in III/V Materials, Epitaxial Microstructures, High-Speed Heterostructure Devices, Oxygen in Silicon, and others promise that this tradition ...

  12. SILICON REFINING BY VACUUM TREATMENT

    Directory of Open Access Journals (Sweden)

    André Alexandrino Lotto

    2014-12-01

    Full Text Available This work aims to investigate the phosphorus removal by vacuum from metallurgical grade silicon (MGSi (98.5% to 99% Si. Melting experiments were carried out in a vacuum induction furnace, varying parameters such as temperature, time and relation area exposed to the vacuum / volume of molten silicon. The results of chemical analysis were obtained by inductively coupled plasma (ICP, and evaluated based on thermodynamic and kinetic aspects of the reaction of vaporization of the phosphorus in the silicon. The phosphorus was decreased from 33 to approximately 1.5 ppm after three hours of vacuum treatment, concluding that the evaporation step is the controlling step of the process for parameters of temperature, pressure and agitation used and refining by this process is technically feasible.

  13. Wetting and infiltration of nitride bonded silicon nitride by liquid silicon

    Science.gov (United States)

    Schneider, V.; Reimann, C.; Friedrich, J.

    2016-04-01

    Nitride bonded silicon nitride (NBSN) is a promising crucible material for the repeated use in the directional solidification of multicrystalline (mc) silicon ingots for photovoltaic applications. Due to wetting and infiltration, however, silicon nitride in its initial state does not offer the desired reusability. In this work the sessile drop method is used to systematically study the wetting and infiltration behavior of NBSN after applying different oxidation procedures. It is found that the wetting of the NBSN crucible by liquid silicon can be prevented by the oxidation of the geometrical surface. The infiltration of liquid silicon into the porous crucible can be suppressed by oxygen enrichment within the volume of the NBSN, i.e. at the pore walls of the crucibles. The realized reusability of the NBSN is demonstrated by reusing a NBSN crucible six times for the directional solidification of undoped multicrystalline silicon ingots.

  14. Evaluating Equating Results: Percent Relative Error for Chained Kernel Equating

    Science.gov (United States)

    Jiang, Yanlin; von Davier, Alina A.; Chen, Haiwen

    2012-01-01

    This article presents a method for evaluating equating results. Within the kernel equating framework, the percent relative error (PRE) for chained equipercentile equating was computed under the nonequivalent groups with anchor test (NEAT) design. The method was applied to two data sets to obtain the PRE, which can be used to measure equating…

  15. 35 GHz integrated circuit rectifying antenna with 33 percent efficiency

    Science.gov (United States)

    Yoo, T.-W.; Chang, K.

    1991-01-01

    A 35 GHz integrated circuit rectifying antenna (rectenna) has been developed using a microstrip dipole antenna and beam-lead mixer diode. Greater than 33 percent conversion efficiency has been achieved. The circuit should have applications in microwave/millimeter-wave power transmission and detection.

  16. Photonic Crystal Sensors Based on Porous Silicon

    OpenAIRE

    Claudia Pacholski

    2013-01-01

    Porous silicon has been established as an excellent sensing platform for the optical detection of hazardous chemicals and biomolecular interactions such as DNA hybridization, antigen/antibody binding, and enzymatic reactions. Its porous nature provides a high surface area within a small volume, which can be easily controlled by changing the pore sizes. As the porosity and consequently the refractive index of an etched porous silicon layer depends on the electrochemial etching conditions photo...

  17. Serum Predictors of Percent Lean Mass in Young Adults.

    Science.gov (United States)

    Lustgarten, Michael S; Price, Lori L; Phillips, Edward M; Kirn, Dylan R; Mills, John; Fielding, Roger A

    2016-08-01

    Lustgarten, MS, Price, LL, Phillips, EM, Kirn, DR, Mills, J, and Fielding, RA. Serum predictors of percent lean mass in young adults. J Strength Cond Res 30(8): 2194-2201, 2016-Elevated lean (skeletal muscle) mass is associated with increased muscle strength and anaerobic exercise performance, whereas low levels of lean mass are associated with insulin resistance and sarcopenia. Therefore, studies aimed at obtaining an improved understanding of mechanisms related to the quantity of lean mass are of interest. Percent lean mass (total lean mass/body weight × 100) in 77 young subjects (18-35 years) was measured with dual-energy x-ray absorptiometry. Twenty analytes and 296 metabolites were evaluated with the use of the standard chemistry screen and mass spectrometry-based metabolomic profiling, respectively. Sex-adjusted multivariable linear regression was used to determine serum analytes and metabolites significantly (p ≤ 0.05 and q ≤ 0.30) associated with the percent lean mass. Two enzymes (alkaline phosphatase and serum glutamate oxaloacetate aminotransferase) and 29 metabolites were found to be significantly associated with the percent lean mass, including metabolites related to microbial metabolism, uremia, inflammation, oxidative stress, branched-chain amino acid metabolism, insulin sensitivity, glycerolipid metabolism, and xenobiotics. Use of sex-adjusted stepwise regression to obtain a final covariate predictor model identified the combination of 5 analytes and metabolites as overall predictors of the percent lean mass (model R = 82.5%). Collectively, these data suggest that a complex interplay of various metabolic processes underlies the maintenance of lean mass in young healthy adults.

  18. Silicon photonics III systems and applications

    CERN Document Server

    Lockwood, David

    2016-01-01

    This book is volume III of a series of books on silicon photonics. It reports on the development of fully integrated systems where many different photonics component are integrated together to build complex circuits. This is the demonstration of the fully potentiality of silicon photonics. It contains a number of chapters written by engineers and scientists of the main companies, research centers and universities active in the field. It can be of use for all those persons interested to know the potentialities and the recent applications of silicon photonics both in microelectronics, telecommunication and consumer electronics market.

  19. Silicon Micromachined Microlens Array for THz Antennas

    Science.gov (United States)

    Lee, Choonsup; Chattopadhyay, Goutam; Mehdi, IImran; Gill, John J.; Jung-Kubiak, Cecile D.; Llombart, Nuria

    2013-01-01

    5 5 silicon microlens array was developed using a silicon micromachining technique for a silicon-based THz antenna array. The feature of the silicon micromachining technique enables one to microfabricate an unlimited number of microlens arrays at one time with good uniformity on a silicon wafer. This technique will resolve one of the key issues in building a THz camera, which is to integrate antennas in a detector array. The conventional approach of building single-pixel receivers and stacking them to form a multi-pixel receiver is not suited at THz because a single-pixel receiver already has difficulty fitting into mass, volume, and power budgets, especially in space applications. In this proposed technique, one has controllability on both diameter and curvature of a silicon microlens. First of all, the diameter of microlens depends on how thick photoresist one could coat and pattern. So far, the diameter of a 6- mm photoresist microlens with 400 m in height has been successfully microfabricated. Based on current researchers experiences, a diameter larger than 1-cm photoresist microlens array would be feasible. In order to control the curvature of the microlens, the following process variables could be used: 1. Amount of photoresist: It determines the curvature of the photoresist microlens. Since the photoresist lens is transferred onto the silicon substrate, it will directly control the curvature of the silicon microlens. 2. Etching selectivity between photoresist and silicon: The photoresist microlens is formed by thermal reflow. In order to transfer the exact photoresist curvature onto silicon, there needs to be etching selectivity of 1:1 between silicon and photoresist. However, by varying the etching selectivity, one could control the curvature of the silicon microlens. The figure shows the microfabricated silicon microlens 5 x5 array. The diameter of the microlens located in the center is about 2.5 mm. The measured 3-D profile of the microlens surface has a

  20. Percent Errors in the Estimation of Demand for Secondary Items.

    Science.gov (United States)

    1985-11-01

    percent errors, and the program change factor (PCF) to predict item demana during the procurement *’ leadtime (PROLT) ior the item. The PCF accounts for...type of demand it was. It may"-- have been demanded over two years ago or it may nave been a non-recurring demana . Since CC b only retains two years of...observed distributions could be compared with negative binomial distributions. For each item the computed ratio of actual demana to expected demand was

  1. The 50 percent solution to reducing energy costs.

    Science.gov (United States)

    Whitson, B Alan

    2012-11-01

    Hospitals can use a five-step process to achieve energy savings: Define a minimum acceptable ROI or hurdle rate. Seek incentives, rebates, and tax benefits. Set a 10-year investment horizon for all project portfolios. Create a system for tracking and reporting the operational and financial performance of the project portfolios. At the end of the year, return 50 percent of the savings to the facilities department and use the rest to fund additional projects.

  2. Intertemporal discoordination in the 100 percent reserve banking system

    OpenAIRE

    Baeriswyl, Romain

    2014-01-01

    The 100%-Money Plan advocated by Fisher (1936) has a Misesian flavor as it aims at mitigating intertemporal discoordination by reducing (i) the discrepancy between investment and voluntary savings, and (ii) the manipulation of interest rates by monetary injections. Recent proposals to adopt the 100 percent reserve banking system, such as the Chicago Plan Revisited by Benes and Kumhof (2013) or the Limited Purpose Banking by Kotlikoff (2010), take, however, a fundamentally different attitude t...

  3. Reactive Melt Infiltration Of Silicon Into Porous Carbon

    Science.gov (United States)

    Behrendt, Donald R.; Singh, Mrityunjay

    1994-01-01

    Report describes study of synthesis of silicon carbide and related ceramics by reactive melt infiltration of silicon and silicon/molybdenum alloys into porous carbon preforms. Reactive melt infiltration has potential for making components in nearly net shape, performed in less time and at lower temperature. Object of study to determine effect of initial pore volume fraction, pore size, and infiltration material on quality of resultant product.

  4. Delayed fracture of silicon: Silicon sheet growth development for the large area silicon sheet task of the low cost silicon solar array project

    Science.gov (United States)

    Chen, T. J.; Knapp, W. J.

    1978-01-01

    Bar specimens were cut from ingots of single crystal silicon, and acid etched prior to testing. Artificial surface flaws were introduced in specimens by indentation with a Knoop hardness tester. The specimens were loaded in four-point bending to 95 percent of the nominal fracture stress, while keeping the surface area, containing the flaw, wet with test liquids. No evidence of delayed fracture, and, therefore stress corrosion, of single crystal silicon was observed for liquid environments including water, acetone, and aqueous solutions of NaCl, NH4OH, and HNO3, when tested with a flaw parallel to a (110) surface. The fracture toughness was calculated.

  5. Highly permeable and mechanically robust silicon carbide hollow fiber membranes

    NARCIS (Netherlands)

    de Wit, Patrick; Kappert, Emiel; Lohaus, T.; Wessling, Matthias; Nijmeijer, Arian; Benes, Nieck Edwin

    2015-01-01

    Silicon carbide (SiC) membranes have shown large potential for applications in water treatment. Being able to make these membranes in a hollow fiber geometry allows for higher surface-to-volume ratios. In this study, we present a thermal treatment procedure that is tuned to produce porous silicon

  6. Highly permeable and mechanically robust silicon carbide hollow fiber membranes

    NARCIS (Netherlands)

    Wit, de P.; Kappert, Emiel J.; Lohaus, T.; Wessling, M.; Nijmeijer, A.; Benes, N.E.

    2015-01-01

    Silicon carbide (SiC) membranes have shown large potential for applications in water treatment. Being able to make these membranes in a hollow fiber geometry allows for higher surface-to-volume ratios. In this study, we present a thermal treatment procedure that is tuned to produce porous silicon ca

  7. Silicon carbide-free graphene growth on silicon for lithium-ion battery with high volumetric energy density

    Science.gov (United States)

    Son, In Hyuk; Hwan Park, Jong; Kwon, Soonchul; Park, Seongyong; Rümmeli, Mark H.; Bachmatiuk, Alicja; Song, Hyun Jae; Ku, Junhwan; Choi, Jang Wook; Choi, Jae-man; Doo, Seok-Gwang; Chang, Hyuk

    2015-01-01

    Silicon is receiving discernable attention as an active material for next generation lithium-ion battery anodes because of its unparalleled gravimetric capacity. However, the large volume change of silicon over charge–discharge cycles weakens its competitiveness in the volumetric energy density and cycle life. Here we report direct graphene growth over silicon nanoparticles without silicon carbide formation. The graphene layers anchored onto the silicon surface accommodate the volume expansion of silicon via a sliding process between adjacent graphene layers. When paired with a commercial lithium cobalt oxide cathode, the silicon carbide-free graphene coating allows the full cell to reach volumetric energy densities of 972 and 700 Wh l−1 at first and 200th cycle, respectively, 1.8 and 1.5 times higher than those of current commercial lithium-ion batteries. This observation suggests that two-dimensional layered structure of graphene and its silicon carbide-free integration with silicon can serve as a prototype in advancing silicon anodes to commercially viable technology. PMID:26109057

  8. Silicon carbide-free graphene growth on silicon for lithium-ion battery with high volumetric energy density.

    Science.gov (United States)

    Son, In Hyuk; Hwan Park, Jong; Kwon, Soonchul; Park, Seongyong; Rümmeli, Mark H; Bachmatiuk, Alicja; Song, Hyun Jae; Ku, Junhwan; Choi, Jang Wook; Choi, Jae-Man; Doo, Seok-Gwang; Chang, Hyuk

    2015-06-25

    Silicon is receiving discernable attention as an active material for next generation lithium-ion battery anodes because of its unparalleled gravimetric capacity. However, the large volume change of silicon over charge-discharge cycles weakens its competitiveness in the volumetric energy density and cycle life. Here we report direct graphene growth over silicon nanoparticles without silicon carbide formation. The graphene layers anchored onto the silicon surface accommodate the volume expansion of silicon via a sliding process between adjacent graphene layers. When paired with a commercial lithium cobalt oxide cathode, the silicon carbide-free graphene coating allows the full cell to reach volumetric energy densities of 972 and 700 Wh l(-1) at first and 200th cycle, respectively, 1.8 and 1.5 times higher than those of current commercial lithium-ion batteries. This observation suggests that two-dimensional layered structure of graphene and its silicon carbide-free integration with silicon can serve as a prototype in advancing silicon anodes to commercially viable technology.

  9. A 99 percent purity molecular sieve oxygen generator

    Science.gov (United States)

    Miller, G. W.

    1991-01-01

    Molecular sieve oxygen generating systems (MSOGS) have become the accepted method for the production of breathable oxygen on military aircraft. These systems separate oxygen for aircraft engine bleed air by application of pressure swing adsorption (PSA) technology. Oxygen is concentrated by preferential adsorption in nitrogen in a zeolite molecular sieve. However, the inability of current zeolite molecular sieves to discriminate between oxygen and argon results in an oxygen purity limitations of 93-95 percent (both oxygen and argon concentrate). The goal was to develop a new PSA process capable of exceeding the present oxygen purity limitations. A novel molecular sieve oxygen concentrator was developed which is capable of generating oxygen concentrations of up to 99.7 percent directly from air. The process is comprised of four absorbent beds, two containing a zeolite molecular sieve and two containing a carbon molecular sieve. This new process may find use in aircraft and medical breathing systems, and industrial air separation systems. The commercial potential of the process is currently being evaluated.

  10. Silicon-on Ceramic Process: Silicon Sheet Growth and Device Development for the Large-area Silicon Sheet and Cell Development Tasks of the Low-cost Solar Array Project

    Science.gov (United States)

    Chapman, P. W.; Zook, J. D.; Heaps, J. D.; Grung, B. L.; Koepke, B.; Schuldt, S. B.

    1979-01-01

    The technical and economic feasibility of producing solar cell-quality silicon was investigated. This was done by coating one surface of carbonized ceramic substrates with a thin layer of large-grain polycrystalline silicon from the melt. Significant progress in the following areas was demonstrated: (1) fabricating a 10 sq cm cell having 9.9 percent conversion efficiency; (2) producing a 225 sq cm layer of sheet silicon; and (3) obtaining 100 microns thick coatings at pull speed of 0.15 cm/sec, although approximately 50 percent of the layer exhibited dendritic growth.

  11. Optical diffusers based on silicone emulsions

    Science.gov (United States)

    Wang, Jui-Hao; Lien, Shui-Yang; Ho, Jeng-Rong; Shih, Teng-Kai; Chen, Chia-Fu; Chen, Chien-Chung; Whang, Wha-Tzong

    2009-12-01

    The present study provides an experimental approach for fabricating optical diffuser films based on silicone emulsions. The silicone emulsion consisting of silicone polymer (Sylgard 184) and NaCl aq. solution was used as the optical material of diffusers, wherein NaCl aq. solution was severed as surfactant to stabilize the emulsions. After stirring mechanically, microscaled water drop with various sizes distributed randomly in silicone polymer, wherein water drop was used as scattering diffusion particles. To modulate the volume of NaCl aq. solution, the diffusing performance of diffusers could be change by different amount drop particles. Thereafter, an optical examination was carried out to characterize optical properties, transmittance, and light diffusivity of volumetric diffuser films.

  12. Semiconductors and semimetals oxygen in silicon

    CERN Document Server

    Willardson, Robert K; Beer, Albert C; Shimura, Fumio

    1994-01-01

    This volume reviews the latest understanding of the behavior and roles of oxygen in silicon, which will carry the field into the ULSI era from the experimental and theoretical points of view. The fourteen chapters, written by recognized authorities representing industrial and academic institutions, cover thoroughly the oxygen related phenomena from the crystal growth to device fabrication processes, as well as indispensable diagnostic techniques for oxygen.Key Features* Comprehensive study of the behavior of oxygen in silicon* Discusses silicon crystals for VLSI and ULSI applications* Thorough coverage from crystal growth to device fabrication* Edited by technical experts in the field* Written by recognized authorities from industrial and academic institutions* Useful to graduate students, scientists in other disciplines, and active participants in the arena of silicon-based microelectronics research* 297 original line drawings

  13. Silicone-Rubber Microvalves Actuated by Paraffin

    Science.gov (United States)

    Svelha, Danielle; Feldman, Sabrina; Barsic, David

    2004-01-01

    Microvalves containing silicone-rubber seals actuated by heating and cooling of paraffin have been proposed for development as integral components of microfluidic systems. In comparison with other microvalves actuated by various means (electrostatic, electromagnetic, piezoelectric, pneumatic, and others), the proposed valves (1) would contain simpler structures that could be fabricated at lower cost and (2) could be actuated by simpler (and thus less expensive) control systems. Each valve according to the proposal would include a flow channel bounded on one side by a flat surface and on the other side by a curved surface defined by an arched-cross-section, elastic seal made of silicone rubber [polydimethylsilane (PDMS)]. The seal would be sized and shaped so that the elasticity of the PDMS would hold the channel open except when the seal was pressed down onto the flat surface to close the channel. The principle of actuation would exploit the fact that upon melting or freezing, the volume of a typical paraffin increases or decreases, respectively, by about 15 percent. In a valve according to the proposal, the seal face opposite that of the channel would be in contact with a piston-like plug of paraffin. In the case of a valve designed to be normally open at ambient temperature, one would use a paraffin having a melting temperature above ambient. The seal would be pushed against the flat surface to close the channel by heating the paraffin above its melting temperature. In the case of a valve designed to be normally closed at ambient temperature, one would use a paraffin having a melting temperature below ambient. The seal would be allowed to spring away from the flat surface to open the channel by cooling the paraffin below its melting temperature. The availability of paraffins that have melting temperatures from 70 to +80 C should make it possible to develop a variety of normally closed and normally open valves. The figure depicts examples of prototype normally

  14. Development of alternate silicone potting compounds. Volume 8. Development of an alternate substitute for Dow Corning aerospace sealant DC93-122 based on Sylgard 184 and dielectric gel Q3-6527

    Energy Technology Data Exchange (ETDEWEB)

    Cady, W.E.; Buckner, A.T.

    1981-02-09

    A second substitute was formulated for Dow Corning DC93-122 silicone potting compound because the first substitute proved so strong and hard. The second substitute was made weaker by substituting Sylgard 184 for Sylgard 186 and by adding dielectric gel Q3-6527. Accelerator QCF3-6559, DC1107 fluid, and Cabosil Grade MS75 silicon dioxide were still required. To reduce the porosity of the potting, the amount of DC1107 fluid in the formulation was minimized, which required adding a relatively large amount of accelerator (as was done in the first substitute). Dielectric gel Q3-6527 used alone required considerably less silicon dioxide to achieve a non-flow state than did Sylgard 184 or any of its blends with Q3-6527.

  15. Systolic Pressure in Different Percents of Stenosis at Major Arteries

    CERN Document Server

    Mirzaee, Mohammad Reza; Firoozabadi, Bahar; Dandaneband, Meitham

    2016-01-01

    - Modeling Human cardiovascular system is always an important issue. One of the most effective methods is using lumped model to reach to a complete model of human cardiovascular system. Such modeling with advanced considerations is used in this paper. Some of these considerations are as follow: Exact simulating of ventricles as pressure suppliers, peristaltic motion of descending arteries as additional suppliers, and dividing each vessel into more than one compartment to reach more accurate answers. Finally a circuit with more than 150 RLC segments and different elements is made. Then the verification of our complex circuit is done and at the end, obstruction as an important abnormality is investigated. For this aim different percents of obstruction in vital arteries are considered and the results are brought as different graphs at the end. According to physiological texts the citation of our simulation and its results are obvious. To earn productive information about arteries characteristics a 36-vessels mod...

  16. One Percent Strömvil Photometry in M 67

    Science.gov (United States)

    Philip, A. G. D.; Boyle, R. P.; Janusz, R.

    2005-05-01

    The Vatican Advanced Technology Telescope on Mt. Graham is being used in a program of CCD photometry of open and globular clusters. We are using the Ströomvil System (Straižys et al. 1996), a combination of the Strömgren and Vilnius Systems. This system allows stars to be classified as to temperature, surface gravity, metallicity and reddening from the photometric measures alone. However, to make accurate estimates of the stellar parameters the photometry should be accurate to 1 or 1.5 percent. In our initial runs on the VATT we did not achieve this accuracy. The problem turned out to be scattered light in the telescope and this has now been reduced so we can do accurate photometry. Boyle has written a routine in IRAF which allows us to correct the flats for any differences. We take rotated frames and also frames which are offset in position by one third of a frame, east-west and north-south. Measures of the offset stars give us the corrections that need to be made to the flat. Robert Janusz has written a program, the CommandLog, which allows us to paste IRAF commands in the correct order to reduce measures made on a given observing run. There is an automatic version where one can test various parameters and get a set of solutions. Now we have a set of Strömvil frames in the open cluster, M 67 and we compare our color-magnitude diagram with those of BATC (Fan et al. 1996) and Vilnius (Boyle et al. 1998). A preliminary report of the M 67 photometry will be found in Laugalys et al. (2004). Here we report on a selected set of stars in the M 67 frames, those with errors 1 percent or less.

  17. Microstructure Control of Columnar-Grained Silicon Substrate Solidified from Silicon Melts Using Gas Pressure

    Directory of Open Access Journals (Sweden)

    Jun-Kyu Lee

    2015-01-01

    Full Text Available A silicon substrate with the dimensions of 100 × 140 × 0.3 mm was grown directly from liquid silicon with gas pressure. The silicon melt in the sealed melting part was injected into the growth part at applied pressure of 780–850 Torr. The solidified silicon substrate was then transferred by the pull of the cooled dummy bar. A desirable structure with a liquid-solid interface perpendicular to the pulling direction was formed when the mold temperature in the solidification zone of the growth part was much higher than that of the dummy bar, as this technique should be able to overcome thermal loss through the molds and the limited heat flux derived from the very narrow contact area between the silicon melt and the dummy bar. In addition, because the metallic impurities and expansion of volume during solidification are preferably moved to a liquid phase, a high-quality silicon substrate, without defects such as cracks and impurities in the substrate, could be manufactured in the interface structure. The present study reports the experimental findings on a new and direct growth system for obtaining silicon substrates characterized by high quality and productivity, as a candidate for alternate routes for the fabrication of silicon substrates.

  18. Exceptional plasticity of silicon nanobridges

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, Tadashi; Sato, Takaaki; Toshiyoshi, Hiroshi; Collard, Dominique; Fujita, Hiroyuki [University of Tokyo, Institute of Industrial Science, 4-6-1 Komaba Meguro, Tokyo 153-8505 (Japan); Cleri, Fabrizio [Institut d' Electronique Microelectronique et Nanotechnologie (CNRS UMR 8520), Universite de Lille I, Avenue Poincare BP60069 59652 Villeneuve d' Ascq (France); Kakushima, Kuniyuki [Tokyo Institute of Technology, 4259, Nagatsuda, Midori, Yokohama, Kanagawa 226-8502 (Japan); Mita, Makoto [Department of Spacecraft Engineering, Japan Aerospace Exploration Agency, 3-1-1, Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan); Miyata, Masaki; Itamura, Noriaki; Sasaki, Naruo [Department of Materials and Life Sciences, Seikei University, 3-3-1, Kitamachi, Kichijoji, Musashino, Tokyo 180-8633 (Japan); Endo, Junji, E-mail: tadashii@iis.u-tokyo.ac.jp [FK Optical laboratory, 1-13-4 Nakano Niiza Saitama, 352-0005 (Japan)

    2011-09-02

    The plasticity of covalently bonded materials is a subject at the forefront of materials science, bearing on a wide range of technological and fundamental aspects. However, covalent materials fracture in a brittle manner when the deformation exceeds just a few per cent. It is predicted that a macroscopically brittle material like silicon can show nanoscale plasticity. Here we report the exceptional plasticity observed in silicon nanocontacts ('nanobridges') at room temperature using a special experimental setup combining a transmission electron microscope and a microelectromechanical system. When accounting for surface diffusion, we succeeded in elongating the nanocontact into a wire-like structure, with a fivefold increase in volume, up to more than twenty times the original length. Such a large plasticity was caused by the stress-assisted diffusion and the sliding of the intergranular, amorphous-like material among the nanocrystals.

  19. Supersonic Dislocation Bursts in Silicon

    Science.gov (United States)

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

    2016-06-01

    Dislocations are the primary agents of permanent deformation in crystalline solids. Since the theoretical prediction of supersonic dislocations over half a century ago, there is a dearth of experimental evidence supporting their existence. Here we use non-equilibrium molecular dynamics simulations of shocked silicon to reveal transient supersonic partial dislocation motion at approximately 15 km/s, faster than any previous in-silico observation. Homogeneous dislocation nucleation occurs near the shock front and supersonic dislocation motion lasts just fractions of picoseconds before the dislocations catch the shock front and decelerate back to the elastic wave speed. Applying a modified analytical equation for dislocation evolution we successfully predict a dislocation density of 1.5 × 1012 cm-2 within the shocked volume, in agreement with the present simulations and realistic in regards to prior and on-going recovery experiments in silicon.

  20. Wet-chemical systems and methods for producing black silicon substrates

    Energy Technology Data Exchange (ETDEWEB)

    Yost, Vernon; Yuan, Hao-Chih; Page, Matthew

    2015-05-19

    A wet-chemical method of producing a black silicon substrate. The method comprising soaking single crystalline silicon wafers in a predetermined volume of a diluted inorganic compound solution. The substrate is combined with an etchant solution that forms a uniform noble metal nanoparticle induced Black Etch of the silicon wafer, resulting in a nanoparticle that is kinetically stabilized. The method comprising combining with an etchant solution having equal volumes acetonitrile/acetic acid:hydrofluoric acid:hydrogen peroxide.

  1. Fretting wear in titanium, Monel-400, and cobalt 25-percent-molybdenum using scanning electron microscopy

    Science.gov (United States)

    Bill, R. C.

    1972-01-01

    Damage scar volume measurements taken from like metal fretting pairs combined with scanning electron microscopy observations showed that three sequentially operating mechanisms result in the fretting of titanium, Monel-400, and cobalt - 25-percent molybdenum. Initially, adhesion and plastic deformation of the surface played an important role. This was followed after a few hundred cycles by a fatigue mechanism which produced spall-like pits in the damage scar. Finally, a combination of oxidation and abrasion by debris particles became most significant. Damage scar measurements made on several elemental metals after 600,000 fretting cycles suggested that the ratio of oxide hardness to metal hardness was a measure of the susceptibility of a metal to progressive damage by fretting.

  2. Copper-assisted, anti-reflection etching of silicon surfaces

    Science.gov (United States)

    Toor, Fatima; Branz, Howard

    2014-08-26

    A method (300) for etching a silicon surface (116) to reduce reflectivity. The method (300) includes electroless deposition of copper nanoparticles about 20 nanometers in size on the silicon surface (116), with a particle-to-particle spacing of 3 to 8 nanometers. The method (300) includes positioning (310) the substrate (112) with a silicon surface (116) into a vessel (122). The vessel (122) is filled (340) with a volume of an etching solution (124) so as to cover the silicon surface (116). The etching solution (124) includes an oxidant-etchant solution (146), e.g., an aqueous solution of hydrofluoric acid and hydrogen peroxide. The silicon surface (116) is etched (350) by agitating the etching solution (124) with, for example, ultrasonic agitation, and the etching may include heating (360) the etching solution (124) and directing light (365) onto the silicon surface (116). During the etching, copper nanoparticles enhance or drive the etching process.

  3. Nanocrystalline silicon films prepared by laser-induced crystallization

    Institute of Scientific and Technical Information of China (English)

    傅广生; 于威; 李社强; 侯海虹; 彭英才; 韩理

    2003-01-01

    The excimer laser-induced crystallization technique has been used to investigate the preparation of nanocrystalline silicon (nc-Si) from amorphous silicon (α-Si) thin films on silicon or glass substrates. The α-Si films without hydrogen grown by pulsed-laser deposition are chosen as precursor to avoid the problem of hydrogen effluence during annealing.Analyses have been performed by scanning electron microscopy, atomic force microscopy, Raman scattering spectroscopy and high-resolution transmission-electron microscopy. Experimental results show that silicon nanocrystals can be formed through laser annealing. The growth characters of nc-Si are strongly dependent on the laser energy density. It is shown that the volume of the molten silicon predominates essentially the grain size of nc-Si, and the surface tension of the crystallized silicon is responsible for the mechanism of nc-Si growth.

  4. Doping Silicon Wafers with Boron by Use of Silicon Paste

    Institute of Scientific and Technical Information of China (English)

    Yu Gao; Shu Zhou; Yunfan Zhang; Chen Dong; Xiaodong Pi; Deren Yang

    2013-01-01

    In this work we introduce recently developed silicon-paste-enabled p-type doping for silicon.Boron-doped silicon nanoparticles are synthesized by a plasma approach.They are then dispersed in solvents to form silicon paste.Silicon paste is screen-printed at the surface of silicon wafers.By annealing,boron atoms in silicon paste diffuse into silicon wafers.Chemical analysis is employed to obtain the concentrations of boron in silicon nanoparticles.The successful doping of silicon wafers with boron is evidenced by secondary ion mass spectroscopy (SIMS) and sheet resistance measurements.

  5. Silicon: electrochemistry and luminescence

    NARCIS (Netherlands)

    Kooij, Ernst Stefan

    1997-01-01

    The electrochemistry of crystalline and porous silicon and the luminescence from porous silicon has been studied. One chapter deals with a model for the anodic dissolution of silicon in HF solution. In following chapters both the electrochemistry and various ways of generating visible luminescenc

  6. Silicon: electrochemistry and luminescence

    NARCIS (Netherlands)

    Kooij, Ernst Stefan

    1997-01-01

    The electrochemistry of crystalline and porous silicon and the luminescence from porous silicon has been studied. One chapter deals with a model for the anodic dissolution of silicon in HF solution. In following chapters both the electrochemistry and various ways of generating visible

  7. Silicon: electrochemistry and luminescence

    NARCIS (Netherlands)

    Kooij, Ernst Stefan

    2001-01-01

    The electrochemistry of crystalline and porous silicon and the luminescence from porous silicon has been studied. One chapter deals with a model for the anodic dissolution of silicon in HF solution. In following chapters both the electrochemistry and various ways of generating visible luminescenc

  8. A three-dimensional theoretical model of the relationship between cavernosal expandability and percent cavernosal smooth muscle.

    Science.gov (United States)

    Luo, Haibiao; Goldstein, Irwin; Udelson, Daniel

    2007-05-01

    Percent corporal smooth muscle content, a traditional predictor of corporal veno-occlusive function, is invasive and clinically assessed by histomorphometric analyses of erectile tissue biopsies. Cavernosal "expandability" which may be a more physiologically relevant parameter is a measure of work performed to achieve penile erection, and as a consequence, an indicator of the ability to approach maximum penile volume at low intracavernosal pressure. To demonstrate that cavernosal "expandability" determined by noninvasive methodology can replace the determination of percent smooth muscle. To predict Young's modulus for the corpora cavernosa in rabbits and, this by inference, in humans; the latter facilitates the comparison of resistance to penile expansion presented by the tunica vs. cavernosal tissue. A refined three-dimensional formula for cavernosal expandability, defined as the negative reciprocal of the cavernosal bulk modulus in the semierect state, was derived as a function of percent corporal smooth muscle content, using principles of engineering mechanics of materials. The model included Young's modulus, E, for the corpora cavernosa as an unknown parameter. Volume-pressure data obtained from three groups of New Zealand white rabbits: (i) control group (N = 7); (ii) hypercholesterolemic group (N = 5) on 0.5%; (iii) atherosclerotic group (N = 8), was plotted, and compared with the model. Data points of mean cavernosal expandability (0.012-0.017 (mm Hg)(-1)) vs. percent trabecular smooth muscle content (33.9-45.4%) for the three groups of rabbits were analyzed. The revised model formula was fitted to the existing rabbit experimental data points producing a value of Young's modulus equal to 0.01 (MPa). Rabbit cavernosal expandability can predict percent smooth muscle content. Cavernosal Young's modulus can be predicted. Further clinical research efforts to provide human data are needed.

  9. Photonic Crystal Sensors Based on Porous Silicon

    Directory of Open Access Journals (Sweden)

    Claudia Pacholski

    2013-04-01

    Full Text Available Porous silicon has been established as an excellent sensing platform for the optical detection of hazardous chemicals and biomolecular interactions such as DNA hybridization, antigen/antibody binding, and enzymatic reactions. Its porous nature provides a high surface area within a small volume, which can be easily controlled by changing the pore sizes. As the porosity and consequently the refractive index of an etched porous silicon layer depends on the electrochemial etching conditions photonic crystals composed of multilayered porous silicon films with well-resolved and narrow optical reflectivity features can easily be obtained. The prominent optical response of the photonic crystal decreases the detection limit and therefore increases the sensitivity of porous silicon sensors in comparison to sensors utilizing Fabry-Pérot based optical transduction. Development of porous silicon photonic crystal sensors which allow for the detection of analytes by the naked eye using a simple color change or the fabrication of stacked porous silicon photonic crystals showing two distinct optical features which can be utilized for the discrimination of analytes emphasize its high application potential.

  10. Photonic crystal sensors based on porous silicon.

    Science.gov (United States)

    Pacholski, Claudia

    2013-04-09

    Porous silicon has been established as an excellent sensing platform for the optical detection of hazardous chemicals and biomolecular interactions such as DNA hybridization, antigen/antibody binding, and enzymatic reactions. Its porous nature provides a high surface area within a small volume, which can be easily controlled by changing the pore sizes. As the porosity and consequently the refractive index of an etched porous silicon layer depends on the electrochemial etching conditions photonic crystals composed of multilayered porous silicon films with well-resolved and narrow optical reflectivity features can easily be obtained. The prominent optical response of the photonic crystal decreases the detection limit and therefore increases the sensitivity of porous silicon sensors in comparison to sensors utilizing Fabry-Pérot based optical transduction. Development of porous silicon photonic crystal sensors which allow for the detection of analytes by the naked eye using a simple color change or the fabrication of stacked porous silicon photonic crystals showing two distinct optical features which can be utilized for the discrimination of analytes emphasize its high application potential.

  11. Utilization of thermal effects for silicon photonics

    Science.gov (United States)

    Dai, Daoxin; Yu, Longhai; Chen, Sitao; Wu, Hao

    2015-08-01

    Thermal effect plays a key role and has been utilized for various photonic devices. For silicon photonics, the thermal effect is usually important because of the large thermo-optical coefficient of silicon material. This paper gives a review for the utilization of thermal effects for silicon photonics. First, the thermal effect is very beneficial to realize energy-efficient silicon photonic devices with tunability/switchability (including switches, variable optical attenuators, etc). Traditionally metal micro-heater sitting on a buried silicon-on-insulator (SOI) nanowire is used to introduce a phase shift for thermal tunability by injecting a electrical current. An effective way to improve the energy-efficiency of thermal tuning is reducing the volume of the optical waveguide as well as the micro-heater. Our recent work on silicon nanophotonic waveguides with novel nano-heaters based on metal wires as well as graphene ribbons will be summarized. Second, the thermal resistance effect of the metal strip on a hybrid plasmonic waveguide structure can be utilized to realize an ultra-small on-chip photodetector available for an ultra-broad band of wavelength, which will also be discussed.

  12. High efficiency interdigitated back contact silicon solar cells

    Science.gov (United States)

    Verlinden, P.; van de Wiele, F.; Stehelin, G.; Floret, F.; David, J. P.

    Interdigitated back contact (IBC) silicon solar cells with 25.6 percent efficiency at 10 W/sq cm and 24.4 percent at 30 W/ sq cm were fabricated. The authors report on the technological process, which produces a high effective carrier lifetime in the bulk (780 microsec), and on the characterization of the cells. The front side of these cells is textured and has an efficient polka-dot floating tandem junction. IBC and point-contact (PC) cells are fabricated on the same substrate and their efficiencies are compared. The possiblity of reaching 29 percent efficiency at 300X is shown.

  13. Advanced silicon materials for photovoltaic applications

    CERN Document Server

    Pizzini, Sergio

    2012-01-01

    Today, the silicon feedstock for photovoltaic cells comes from processes which were originally developed for the microelectronic industry. It covers almost 90% of the photovoltaic market, with mass production volume at least one order of magnitude larger than those devoted to microelectronics. However, it is hard to imagine that this kind of feedstock (extremely pure but heavily penalized by its high energy cost) could remain the only source of silicon for a photovoltaic market which is in continuous expansion, and which has a cumulative growth rate in excess of 30% in the last few years. Ev

  14. Proton Straggling in Thick Silicon Detectors

    Science.gov (United States)

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

    2017-01-01

    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 k is greater than or equal to 0:3. They are verified by comparison to experimental proton data from a charged particle telescope.

  15. Proton straggling in thick silicon detectors

    Science.gov (United States)

    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.

  16. Chemical Analysis Methods for Silicon Carbide

    Institute of Scientific and Technical Information of China (English)

    Shen Keyin

    2006-01-01

    @@ 1 General and Scope This Standard specifies the determination method of silicon dioxide, free silicon, free carbon, total carbon, silicon carbide, ferric sesquioxide in silicon carbide abrasive material.

  17. Glass-silicon column

    Energy Technology Data Exchange (ETDEWEB)

    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.

  18. Porous silicon gettering

    Energy Technology Data Exchange (ETDEWEB)

    Tsuo, Y.S.; Menna, P.; Al-Jassim, M. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    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.

  19. Silicon Brains

    Science.gov (United States)

    Hoefflinger, Bernd

    Beyond the digital neural networks of Chap. 16, the more radical mapping of brain-like structures and processes into VLSI substrates has been pioneered by Carver Mead more than 30 years ago [1]. The basic idea was to exploit the massive parallelism of such circuits and to create low-power and fault-tolerant information-processing systems. Neuromorphic engineering has recently seen a revival with the availability of deep-submicron CMOS technology, which allows for the construction of very-large-scale mixed-signal systems combining local analog processing in neuronal cells with binary signalling via action potentials. Modern implementations are able to reach the complexity-scale of large functional units of the human brain, and they feature the ability to learn by plasticity mechanisms found in neuroscience. Combined with high-performance programmable logic and elaborate software tools, such systems are currently evolving into user-configurable non-von-Neumann computing systems, which can be used to implement and test novel computational paradigms. The chapter introduces basic properties of biological brains with up to 200 Billion neurons and their 1014 synapses, where action on a synapse takes ˜10 ms and involves an energy of ˜10 fJ. We outline 10x programs on neuromorphic electronic systems in Europe and the USA, which are intended to integrate 108 neurons and 1012 synapses, the level of a cat's brain, in a volume of 1 L and with a power dissipation design an intelligent technical response.

  20. One-dimensional/two-dimensional hybridization for self-supported binder-free silicon-based lithium ion battery anodes.

    Science.gov (United States)

    Wang, Bin; Li, Xianglong; Luo, Bin; Jia, Yuying; Zhi, Linjie

    2013-02-21

    A unique silicon-based anode for lithium ion batteries is developed via the facile hybridization of one-dimensional silicon nanowires and two-dimensional graphene sheets. The resulting paper-like film holds advantages highly desirable for not only accommodating the volume change of silicon, but also facilitating the fast transport of electron and lithium ions.

  1. Near Zero Emissions at 50 Percent Thermal Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2012-12-31

    Detroit Diesel Corporation (DDC) has successfully completed a 10 year DOE sponsored heavy-duty truck engine program, hereafter referred to as the NZ-50 program. This program was split into two major phases. The first phase was called Near-Zero Emission at 50 Percent Thermal Efficiency, and was completed in 2007. The second phase was initiated in 2006, and this phase was named Advancements in Engine Combustion Systems to Enable High-Efficiency Clean Combustion for Heavy-Duty Engines. This phase was completed in September, 2010. The key objectives of the NZ-50 program for this first phase were to: Quantify thermal efficiency degradation associated with reduction of engine-out NOx emissions to the 2007 regulated level of ~1.1 g/hp-hr. Implement an integrated analytical/experimental development plan for improving subsystem and component capabilities in support of emerging engine technologies for emissions and thermal efficiency goals of the program. Test prototype subsystem hardware featuring technology enhancements and demonstrate effective application on a multi-cylinder, production feasible heavy-duty engine test-bed. Optimize subsystem components and engine controls (calibration) to demonstrate thermal efficiency that is in compliance with the DOE 2005 Joule milestone, meaning greater than 45% thermal efficiency at 2007 emission levels. Develop technology roadmap for meeting emission regulations of 2010 and beyond while mitigating the associated degradation in engine fuel consumption. Ultimately, develop technical prime-path for meeting the overall goal of the NZ-50 program, i.e., 50% thermal efficiency at 2010 regulated emissions. These objectives were successfully met during the course of the NZ-50 program. The most noteworthy achievements in this program are summarized as follows: Demonstrated technologies through advanced integrated experiments and analysis to achieve the technical objectives of the NZ-50 program with 50.2% equivalent thermal efficiency under

  2. Dramatic reduction of surface recombination by in situ surface passivation of silicon nanowires.

    Science.gov (United States)

    Dan, Yaping; Seo, Kwanyong; Takei, Kuniharu; Meza, Jhim H; Javey, Ali; Crozier, Kenneth B

    2011-06-08

    Nanowires have unique optical properties and are considered as important building blocks for energy harvesting applications such as solar cells. However, due to their large surface-to-volume ratios, the recombination of charge carriers through surface states reduces the carrier diffusion lengths in nanowires a few orders of magnitude, often resulting in the low efficiency (a few percent or less) of nanowire-based solar cells. Reducing the recombination by surface passivation is crucial for the realization of high-performance nanosized optoelectronic devices but remains largely unexplored. Here we show that a thin layer of amorphous silicon (a-Si) coated on a single-crystalline silicon nanowire, forming a core-shell structure in situ in the vapor-liquid-solid process, reduces the surface recombination nearly 2 orders of magnitude. Under illumination of modulated light, we measure a greater than 90-fold improvement in the photosensitivity of individual core-shell nanowires, compared to regular nanowires without shell. Simulations of the optical absorption of the nanowires indicate that the strong absorption of the a-Si shell contributes to this effect, but we conclude that the effect is mainly due to the enhanced carrier lifetime by surface passivation.

  3. Layered amorphous silicon as negative electrodes in lithium-ion batteries

    Science.gov (United States)

    Zhao, Leyi; Dvorak, D. J.; Obrovac, M. N.

    2016-11-01

    Chemical delithiation is used to prepare bulk quantities of amorphous silicon powder from lithium-silicon compounds. The amorphous silicon materials formed are air and water stable and are found to have layered structures. When cycled in Li-ion half cells, coatings containing layered amorphous silicon are found to have significantly lower volume expansion during lithiation and improved cycling characteristics compared to that of bulk crystalline Si. We suggest chemical delithiation as a convenient method to synthesize bulk quantities of Si powders containing self-organized void spaces that can accommodate volume expansion during lithiation.

  4. Silicon Photonics II Components and Integration

    CERN Document Server

    Lockwood, David J

    2011-01-01

    This book is volume II of a series of books on silicon photonics. It gives a fascinating picture of the state-of-the-art in silicon photonics from a component perspective. It presents a perspective on what can be expected in the near future. It is formed from a selected number of reviews authored by world leaders in the field, and is written from both academic and industrial viewpoints. An in-depth discussion of the route towards fully integrated silicon photonics is presented. This book will be useful not only to physicists, chemists, materials scientists, and engineers but also to graduate students who are interested in the fields of micro- and nanophotonics and optoelectronics.

  5. Breast percent density estimation from 3D reconstructed digital breast tomosynthesis images

    Science.gov (United States)

    Bakic, Predrag R.; Kontos, Despina; Carton, Ann-Katherine; Maidment, Andrew D. A.

    2008-03-01

    Breast density is an independent factor of breast cancer risk. In mammograms breast density is quantitatively measured as percent density (PD), the percentage of dense (non-fatty) tissue. To date, clinical estimates of PD have varied significantly, in part due to the projective nature of mammography. Digital breast tomosynthesis (DBT) is a 3D imaging modality in which cross-sectional images are reconstructed from a small number of projections acquired at different x-ray tube angles. Preliminary studies suggest that DBT is superior to mammography in tissue visualization, since superimposed anatomical structures present in mammograms are filtered out. We hypothesize that DBT could also provide a more accurate breast density estimation. In this paper, we propose to estimate PD from reconstructed DBT images using a semi-automated thresholding technique. Preprocessing is performed to exclude the image background and the area of the pectoral muscle. Threshold values are selected manually from a small number of reconstructed slices; a combination of these thresholds is applied to each slice throughout the entire reconstructed DBT volume. The proposed method was validated using images of women with recently detected abnormalities or with biopsy-proven cancers; only contralateral breasts were analyzed. The Pearson correlation and kappa coefficients between the breast density estimates from DBT and the corresponding digital mammogram indicate moderate agreement between the two modalities, comparable with our previous results from 2D DBT projections. Percent density appears to be a robust measure for breast density assessment in both 2D and 3D x-ray breast imaging modalities using thresholding.

  6. Near Zero Emissions at 50 Percent Thermal Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2012-12-31

    Detroit Diesel Corporation (DDC) has successfully completed a 10 year DOE sponsored heavy-duty truck engine program, hereafter referred to as the NZ-50 program. This program was split into two major phases. The first phase was called Near-Zero Emission at 50 Percent Thermal Efficiency, and was completed in 2007. The second phase was initiated in 2006, and this phase was named Advancements in Engine Combustion Systems to Enable High-Efficiency Clean Combustion for Heavy-Duty Engines. This phase was completed in September, 2010. The key objectives of the NZ-50 program for this first phase were to: Quantify thermal efficiency degradation associated with reduction of engine-out NOx emissions to the 2007 regulated level of ~1.1 g/hp-hr. Implement an integrated analytical/experimental development plan for improving subsystem and component capabilities in support of emerging engine technologies for emissions and thermal efficiency goals of the program. Test prototype subsystem hardware featuring technology enhancements and demonstrate effective application on a multi-cylinder, production feasible heavy-duty engine test-bed. Optimize subsystem components and engine controls (calibration) to demonstrate thermal efficiency that is in compliance with the DOE 2005 Joule milestone, meaning greater than 45% thermal efficiency at 2007 emission levels. Develop technology roadmap for meeting emission regulations of 2010 and beyond while mitigating the associated degradation in engine fuel consumption. Ultimately, develop technical prime-path for meeting the overall goal of the NZ-50 program, i.e., 50% thermal efficiency at 2010 regulated emissions. These objectives were successfully met during the course of the NZ-50 program. The most noteworthy achievements in this program are summarized as follows: Demonstrated technologies through advanced integrated experiments and analysis to achieve the technical objectives of the NZ-50 program with 50.2% equivalent thermal efficiency under

  7. Silicon micro-mold

    Science.gov (United States)

    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.

  8. Silicon nanomaterials platform for bioimaging, biosensing, and cancer therapy.

    Science.gov (United States)

    Peng, Fei; Su, Yuanyuan; Zhong, Yiling; Fan, Chunhai; Lee, Shuit-Tong; He, Yao

    2014-02-18

    Silicon nanomaterials are an important class of nanomaterials with great potential for technologies including energy, catalysis, and biotechnology, because of their many unique properties, including biocompatibility, abundance, and unique electronic, optical, and mechanical properties, among others. Silicon nanomaterials are known to have little or no toxicity due to favorable biocompatibility of silicon, which is an important precondition for biological and biomedical applications. In addition, huge surface-to-volume ratios of silicon nanomaterials are responsible for their unique optical, mechanical, or electronic properties, which offer exciting opportunities for design of high-performance silicon-based functional nanoprobes, nanosensors, and nanoagents for biological analysis and detection and disease treatment. Moreover, silicon is the second most abundant element (after oxygen) on earth, providing plentiful and inexpensive resources for large-scale and low-cost preparation of silicon nanomaterials for practical applications. Because of these attractive traits, and in parallel with a growing interest in their design and synthesis, silicon nanomaterials are extensively investigated for wide-ranging applications, including energy, catalysis, optoelectronics, and biology. Among them, bioapplications of silicon nanomaterials are of particular interest. In the past decade, scientists have made an extensive effort to construct a silicon nanomaterials platform for various biological and biomedical applications, such as biosensors, bioimaging, and cancer treatment, as new and powerful tools for disease diagnosis and therapy. Nonetheless, there are few review articles covering these important and promising achievements to promote the awareness of development of silicon nanobiotechnology. In this Account, we summarize recent representative works to highlight the recent developments of silicon functional nanomaterials for a new, powerful platform for biological and

  9. Silicon dioxide with a silicon interfacial layer as an insulating gate for highly stable indium phosphide metal-insulator-semiconductor field effect transistors

    Science.gov (United States)

    Kapoor, V. J.; Shokrani, M.

    1991-01-01

    A novel gate insulator consisting of silicon dioxide (SiO2) with a thin silicon (Si) interfacial layer has been investigated for high-power microwave indium phosphide (InP) metal-insulator-semiconductor field effect transistors (MISFETs). The role of the silicon interfacial layer on the chemical nature of the SiO2/Si/InP interface was studied by high-resolution X-ray photoelectron spectroscopy. The results indicated that the silicon interfacial layer reacted with the native oxide at the InP surface, thus producing silicon dioxide, while reducing the native oxide which has been shown to be responsible for the instabilities in InP MISFETs. While a 1.2-V hysteresis was present in the capacitance-voltage (C-V) curve of the MIS capacitors with silicon dioxide, less than 0.1 V hysteresis was observed in the C-V curve of the capacitors with the silicon interfacial layer incorporated in the insulator. InP MISFETs fabricated with the silicon dioxide in combination with the silicon interfacial layer exhibited excellent stability with drain current drift of less than 3 percent in 10,000 sec, as compared to 15-18 percent drift in 10,000 sec for devices without the silicon interfacial layer. High-power microwave InP MISFETs with Si/SiO2 gate insulators resulted in an output power density of 1.75 W/mm gate width at 9.7 GHz, with an associated power gain of 2.5 dB and 24 percent power added efficiency.

  10. SILICON CARBIDE FOR SEMICONDUCTORS

    Science.gov (United States)

    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

  11. Silicon Carbide Shapes.

    Science.gov (United States)

    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.

  12. High Efficiency, Low Cost Solar Cells Manufactured Using 'Silicon Ink' on Thin Crystalline Silicon Wafers

    Energy Technology Data Exchange (ETDEWEB)

    Antoniadis, H.

    2011-03-01

    Reported are the development and demonstration of a 17% efficient 25mm x 25mm crystalline Silicon solar cell and a 16% efficient 125mm x 125mm crystalline Silicon solar cell, both produced by Ink-jet printing Silicon Ink on a thin crystalline Silicon wafer. To achieve these objectives, processing approaches were developed to print the Silicon Ink in a predetermined pattern to form a high efficiency selective emitter, remove the solvents in the Silicon Ink and fuse the deposited particle Silicon films. Additionally, standard solar cell manufacturing equipment with slightly modified processes were used to complete the fabrication of the Silicon Ink high efficiency solar cells. Also reported are the development and demonstration of a 18.5% efficient 125mm x 125mm monocrystalline Silicon cell, and a 17% efficient 125mm x 125mm multicrystalline Silicon cell, by utilizing high throughput Ink-jet and screen printing technologies. To achieve these objectives, Innovalight developed new high throughput processing tools to print and fuse both p and n type particle Silicon Inks in a predetermined pat-tern applied either on the front or the back of the cell. Additionally, a customized Ink-jet and screen printing systems, coupled with customized substrate handling solution, customized printing algorithms, and a customized ink drying process, in combination with a purchased turn-key line, were used to complete the high efficiency solar cells. This development work delivered a process capable of high volume producing 18.5% efficient crystalline Silicon solar cells and enabled the Innovalight to commercialize its technology by the summer of 2010.

  13. 3D, Flash, Induced Current Readout for Silicon Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Parker, Sherwood I. [Univ. of Hawaii, Honolulu, HI (United States)

    2014-06-07

    A new method for silicon microstrip and pixel detector readout using (1) 65 nm-technology current amplifers which can, for the first time with silicon microstrop and pixel detectors, have response times far shorter than the charge collection time (2) 3D trench electrodes large enough to subtend a reasonable solid angle at most track locations and so have adequate sensitivity over a substantial volume of pixel, (3) induced signals in addition to, or in place of, collected charge

  14. Photonic Crystal Cavities in Cubic Polytype Silicon Carbide Films

    CERN Document Server

    Radulaski, Marina; Buckley, Sonia; Rundquist, Armand; Provine, J; Alassaad, Kassem; Ferro, Gabriel; Vučković, Jelena

    2013-01-01

    We present the design, fabrication, and characterization of high quality factor and small mode volume planar photonic crystal cavities from cubic (3C) thin films (thickness ~ 200 nm) of silicon carbide (SiC) grown epitaxially on a silicon substrate. We demonstrate cavity resonances across the telecommunications band, with wavelengths from 1250 - 1600 nm. Finally, we discuss possible applications in nonlinear optics, optical interconnects, and quantum information science.

  15. Novel Silicon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Novel silicon nanotubes with inner-diameter of 60-80 nm was prepared using hydrogen-added dechlorination of SiCl4 followed by chemical vapor deposition (CVD) on a NixMgyO catalyst. The TEM observation showed that the suitable reaction temperature is 973 K for the formation of silicon nanotubes. Most of silicon nanotubes have one open end and some have two closed ends. The shape ofnanoscale silicon, however, is a micro-crystal type at 873 K, a rod or needle type at 993 K and an onion-type at 1023 K, respectively.

  16. Breast Implants: Saline vs. Silicone

    Science.gov (United States)

    ... differ in material and consistency, however. Saline breast implants Saline implants are filled with sterile salt water. ... of any age for breast reconstruction. Silicone breast implants Silicone implants are pre-filled with silicone gel — ...

  17. Compton imager using room temperature silicon detectors

    Science.gov (United States)

    Kurfess, James D.; Novikova, Elena I.; Phlips, Bernard F.; Wulf, Eric A.

    2007-08-01

    We have been developing a multi-layer Compton Gamma Ray Imager using position-sensitive, intrinsic silicon detectors. Advantages of this approach include room temperature operation, reduced Doppler broadening, and use of conventional silicon fabrication technologies. We have obtained results on the imaging performance of a multi-layer instrument where each layer consists of a 2×2 array of double-sided strip detectors. Each detector is 63 mm×63 mm×2 mm thick and has 64 strips providing a strip pitch of approximately 0.9 mm. The detectors were fabricated by SINTEF ICT (Oslo Norway) from 100 mm diameter wafers. The use of large arrays of silicon detectors appears especially advantageous for applications that require excellent sensitivity, spectral resolution and imaging such as gamma ray astrophysics, detection of special nuclear materials, and medical imaging. The multiple Compton interactions (three or more) in the low-Z silicon enable the energy and direction of the incident gamma ray to be determined without full deposition of the incident gamma-ray energy in the detector. The performance of large volume instruments for various applications are presented, including an instrument under consideration for NASA's Advanced Compton Telescope (ACT) mission and applications to Homeland Security. Technology developments that could further extend the sensitivity and performance of silicon Compton Imagers are presented, including the use of low-energy (few hundred keV) electron tracking within novel silicon detectors and the potential for a wafer-bonding approach to produce thicker, position-sensitive silicon detectors with an associated reduction of required electronics and instrument cost.

  18. Silicon-on-ceramic coating process. Silicon sheet growth development for the Large-Area Silicon Sheet and Cell Development Tasks of the Low-Cost Silicon Solar Array Project. Quarterly report No. 8, December 28, 1977--March 28, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, P.W. Zook, J.D.; Heaps, J D; Maclolek, R B; Koepke, B; Butter, C D; Schult, S B

    1978-04-20

    A research program to investigate 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 described. The coating methods to be developed are directed toward a minimum-cost process for producing solar cells with a terrestrial conversion efficiency of 12 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 dip-coating method for putting silicon on ceramic (SOC) has been shown to produce solar-cell-quality sheet silicon. This method and a continuous coating process also being investigated have excellent scale-up potential which offers an outstanding cost-effective way to manufacture large-area solar cells. 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. Solar cells with areas from 1 to 10 cm/sup 2/ have been fabricated from material withas-grown surface. Recently, an antireflection (AR) coating has been applied to SOC cells. Conversion efficiencies greater than 9% have been achieved without optimizing series resistance characteristics. Such cells typically have open-circuit voltages and short-circuit current densities of 0.51 V and 20 mA/cm/sup 2/, respectively.

  19. Simulation of the GEM silicon central tracker using GEANT

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, M.L.; Kinnison, W.W.

    1994-01-01

    The silicon central tracker of the GEM detector has been simulated using the high energy physics simulations code GEANT. This paper will describe the level of detail of the geometry of the tracker that is in the code, including the silicon detectors themselves as well as all non-sensitive volumes such as support structures; the digitization, or detector response to particles, of the silicon detectors; the coordinate reconstruction from the digitizations, and some of the results of the simulations regarding the detector performance.

  20. Mixing subattolitre volumes in a quantitative and highly parallel manner with soft matter nanofluidics

    DEFF Research Database (Denmark)

    Christensen, Sune M.; Bolinger, Pierre-Yves; Hatzakis, Nikos;

    2012-01-01

    Handling and mixing ultrasmall volumes of reactants in parallel can increase the throughput and complexity of screening assays while simultaneously reducing reagent consumption. Microfabricated silicon and plastic can provide reliable fluidic devices, but cannot typically handle total volumes sma...

  1. Nonlinear silicon photonics

    Science.gov (United States)

    Borghi, M.; Castellan, C.; Signorini, S.; Trenti, A.; Pavesi, L.

    2017-09-01

    Silicon photonics is a technology based on fabricating integrated optical circuits by using the same paradigms as the dominant electronics industry. After twenty years of fervid development, silicon photonics is entering the market with low cost, high performance and mass-manufacturable optical devices. Until now, most silicon photonic devices have been based on linear optical effects, despite the many phenomenologies associated with nonlinear optics in both bulk materials and integrated waveguides. Silicon and silicon-based materials have strong optical nonlinearities which are enhanced in integrated devices by the small cross-section of the high-index contrast silicon waveguides or photonic crystals. Here the photons are made to strongly interact with the medium where they propagate. This is the central argument of nonlinear silicon photonics. It is the aim of this review to describe the state-of-the-art in the field. Starting from the basic nonlinearities in a silicon waveguide or in optical resonator geometries, many phenomena and applications are described—including frequency generation, frequency conversion, frequency-comb generation, supercontinuum generation, soliton formation, temporal imaging and time lensing, Raman lasing, and comb spectroscopy. Emerging quantum photonics applications, such as entangled photon sources, heralded single-photon sources and integrated quantum photonic circuits are also addressed at the end of this review.

  2. Nonlinear silicon photonics

    Science.gov (United States)

    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.

  3. Periodically poled silicon

    Science.gov (United States)

    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.

  4. ALICE silicon strip module

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    This small silicon detector strip will be inserted into the inner tracking system (ITS) on the ALICE detector at CERN. This detector relies on state-of-the-art particle tracking techniques. These double-sided silicon strip modules have been designed to be as lightweight and delicate as possible as the ITS will eventually contain five square metres of these devices.

  5. SILICON CARBIDE DATA SHEETS

    Science.gov (United States)

    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

  6. Silicon Valley Ecosystem

    Institute of Scientific and Technical Information of China (English)

    Joseph Leu

    2005-01-01

    @@ It is unlikely that any industrial region of the world has received as much scrutiny and study as Silicon Valley. Despite the recent crash of Internet and telecommunications stocks,Silicon Valley remains the world's engine of growth for numerous high-technology sectors.

  7. Photoluminescence of Silicon Nanocrystals in Silicon Oxide

    Directory of Open Access Journals (Sweden)

    L. Ferraioli

    2007-01-01

    Full Text Available Recent results on the photoluminescence properties of silicon nanocrystals embedded in silicon oxide are reviewed and discussed. The attention is focused on Si nanocrystals produced by high-temperature annealing of silicon rich oxide layers deposited by plasma-enhanced chemical vapor deposition. The influence of deposition parameters and layer thickness is analyzed in detail. The nanocrystal size can be roughly controlled by means of Si content and annealing temperature and time. Unfortunately, a technique for independently fine tuning the emission efficiency and the size is still lacking; thus, only middle size nanocrystals have high emission efficiency. Interestingly, the layer thickness affects the nucleation and growth kinetics so changing the luminescence efficiency.

  8. Steps towards silicon optoelectronics

    CERN Document Server

    Starovoytov, A

    1999-01-01

    nanostructure fabrication. Thus, this thesis makes a dual contribution to the chosen field: it summarises the present knowledge on the possibility of utilising optical properties of nanocrystalline silicon in silicon-based electronics, and it reports new results within the framework of the subject. The main conclusion is that due to its promising optoelectronic properties nanocrystalline silicon remains a prospective competitor for the cheapest and fastest microelectronics of the next century. This thesis addresses the issue of a potential future microelectronics technology, namely the possibility of utilising the optical properties of nanocrystalline silicon for optoelectronic circuits. The subject is subdivided into three chapters. Chapter 1 is an introduction. It formulates the oncoming problem for microelectronic development, explains the basics of Integrated Optoelectronics, introduces porous silicon as a new light-emitting material and gives a brief review of other competing light-emitting material syst...

  9. Volume Entropy

    CERN Document Server

    Astuti, Valerio; Rovelli, Carlo

    2016-01-01

    Building on a technical result by Brunnemann and Rideout on the spectrum of the Volume operator in Loop Quantum Gravity, we show that the dimension of the space of the quadrivalent states --with finite-volume individual nodes-- describing a region with total volume smaller than $V$, has \\emph{finite} dimension, bounded by $V \\log V$. This allows us to introduce the notion of "volume entropy": the von Neumann entropy associated to the measurement of volume.

  10. Silicon Heat Pipe Array

    Science.gov (United States)

    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

  11. Silicon germanium mask for deep silicon etching

    KAUST Repository

    Serry, Mohamed

    2014-07-29

    Polycrystalline silicon germanium (SiGe) can offer excellent etch selectivity to silicon during cryogenic deep reactive ion etching in an SF.sub.6/O.sub.2 plasma. Etch selectivity of over 800:1 (Si:SiGe) may be achieved at etch temperatures from -80 degrees Celsius to -140 degrees Celsius. High aspect ratio structures with high resolution may be patterned into Si substrates using SiGe as a hard mask layer for construction of microelectromechanical systems (MEMS) devices and semiconductor devices.

  12. INTRAVASAL INJECTION OF FORMED-IN-PLACE MEDICAL GRADE SILICONE-RUBBER FOR VAS OCCLUSION

    NARCIS (Netherlands)

    SOEBADI, DM; GARDJITO, W; MENSINK, HJA

    This paper describes two consecutive studies: a volume study and an efficacy study. The volume study determined the appropriate volume of Medical Grade Silicone Rubber (MSR) needed to achieve complete occlusion of the vas deferens. This was done by in-vitro testing of 130 human vas specimens

  13. Deep reactive ion etched anti-reflection coatings for sub-millimeter silicon optics.

    Science.gov (United States)

    Gallardo, Patricio A; Koopman, Brian J; Cothard, Nicholas F; Bruno, Sarah Marie M; Cortes-Medellin, German; Marchetti, Galen; Miller, Kevin H; Mockler, Brenna; Niemack, Michael D; Stacey, Gordon; Wollack, Edward J

    2017-04-01

    Refractive optical elements are widely used in millimeter and sub-millimeter (sub-mm) astronomical telescopes. High-resistivity silicon is an excellent material for dielectric lenses given its low loss tangent, high thermal conductivity, and high index of refraction. The high index of refraction of silicon causes a large Fresnel reflectance at the vacuum-silicon interface (up to 30%), which can be reduced with an anti-reflection (AR) coating. In this work, we report techniques for efficiently AR coating silicon at sub-mm wavelengths using deep reactive ion etching (DRIE) and bonding the coated silicon to another silicon optic. Silicon wafers of 100 mm diameter (1 mm thick) were coated and bonded using the silicon direct bonding technique at high temperature (1100°C). No glue is used in this process. Optical tests using a Fourier transform spectrometer show sub-percent reflections for a single-layer DRIE AR coating designed for use at 320 μm on a single wafer. Cryogenic (10 K) measurements of a bonded pair of AR-coated wafers also reached sub-percent reflections. A prototype two-layer DRIE AR coating to reduce reflections and increase bandwidth is presented, and plans for extending this approach are discussed.

  14. High-flux solar furnace processing of crystalline silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Tsuo, Y.S.; Pitts, J.R. [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States); Menna, P. [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)]|[ENEA-Centro Ricerche Fotovoltaiche, Portici 80055 (Italy); Landry, M.D. [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States); Gee, J.M. [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)]|[Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Ciszek, T.F. [National Renewable Energy Laboratory, Golden, Colorado, 80401 (United States)

    1997-02-01

    We studied the processing of crystalline-silicon solar cells using a 10-kW, high-flux solar furnace (HFSF). Major findings of this study include: (1) hydrogenated amorphous silicon films deposited on glass substrates can be converted to microcrystalline silicon by solid-phase crystallization in 5 seconds or less in the HFSF; (2) the presence of concentrated sunlight enhances the diffusion of phosphorus into silicon from a spin-on dopant source; (3) the combination of a porous-silicon surface layer and photo-enhanced impurity diffusion is very effective in gettering impurities from a metallurgical-grade silicon wafer or thin-layer silicon deposited using liquid-phase epitaxy; (4) a 14.1{percent}-efficient crystalline-silicon solar cell with an area of 4.6cm{sup 2} was fabricated using the HFSF for simultaneous diffusion of front n{sup +}-p and back p-p{sup +} junctions; and (5) we have shown that the HFSF can be used to texture crystalline-silicon surfaces and to anneal metal contacts printed on a silicon solar cell. {copyright} {ital 1997 American Institute of Physics.}

  15. Silicon applications in photonics

    Science.gov (United States)

    Jelenski, A. M.; Gawlik, G.; Wesolowski, M.

    2005-09-01

    Silicon technology enabled the miniaturization of computers and other electronic system for information storage, transmission and transformation allowing the development of the Knowledge Based Information Society. Despite the fact that silicon roadmap indicates possibilities for further improvement, already now the speed of electrons and the bandwidth of electronic circuits are not sufficient and photons are commonly utilized for signal transmission through optical fibers and purely photonic circuits promise further improvements. However materials used for these purposes II/V semiconductor compounds, glasses make integration of optoelectronic circuits with silicon complex an expensive. Therefore research on light generation, transformation and transmission in silicon is very active and recently, due to nanotechnology some spectacular results were achieved despite the fact that mechanisms of light generation are still discussed. Three topics will be discussed. Porous silicon was actively investigated due to its relatively efficient electroluminescence enabling its use in light sources. Its index of refraction, differs considerably from the index of silicon, and this allows its utilization for Bragg mirrors, wave guides and photonic crystals. The enormous surface enables several applications on medicine and biotechnology and in particular due to the effective chemo-modulation of its refracting index the design of optical chemosensors. An effective luminescence of doped and undoped nanocrystalline silicon opened another way for the construction of silicon light sources. Optical amplification was already discovered opening perspectives for the construction of nanosilicon lasers. Luminescences was observed at red, green and blue wavelengths. The used technology of silica and ion implantation are compatible with commonly used CMOS technology. Finally the recently developed and proved idea of optically pumped silicon Raman lasers, using nonlinearity and vibrations in the

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

    Science.gov (United States)

    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 orientation of the cubic diamond structure SiGe is aligned with a 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

  17. Recrystallization of polycrystalline silicon

    Science.gov (United States)

    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%.

  18. Porous silicon gettering

    Energy Technology Data Exchange (ETDEWEB)

    Tsuo, Y.S.; Menna, P.; Pitts, J.R. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    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.

  19. Microstructured silicon radiation detector

    Energy Technology Data Exchange (ETDEWEB)

    Okandan, Murat; Derzon, Mark S.; Draper, Bruce L.

    2017-03-14

    A radiation detector comprises a silicon body in which are defined vertical pores filled with a converter material and situated within silicon depletion regions. One or more charge-collection electrodes are arranged to collect current generated when secondary particles enter the silicon body through walls of the pores. The pores are disposed in low-density clusters, have a majority pore thickness of 5 .mu.m or less, and have a majority aspect ratio, defined as the ratio of pore depth to pore thickness, of at least 10.

  20. Emissivity of microstructured silicon.

    Science.gov (United States)

    Maloney, Patrick G; Smith, Peter; King, Vernon; Billman, Curtis; Winkler, Mark; Mazur, Eric

    2010-03-01

    Infrared transmittance and hemispherical-directional reflectance data from 2.5 to 25 microm on microstructured silicon surfaces have been measured, and spectral emissivity has been calculated for this wavelength range. Hemispherical-total emissivity is calculated for the samples and found to be 0.84 before a measurement-induced annealing and 0.65 after the measurement for the sulfur-doped sample. Secondary samples lack a measurement-induced anneal, and reasons for this discrepancy are presented. Emissivity numbers are plotted and compared with a silicon substrate, and Aeroglaze Z306 black paint. Use of microstructured silicon as a blackbody or microbolometer surface is modeled and presented, respectively.

  1. Silicon nanowire hybrid photovoltaics

    KAUST Repository

    Garnett, Erik C.

    2010-06-01

    Silicon nanowire Schottky junction solar cells have been fabricated using n-type silicon nanowire arrays and a spin-coated conductive polymer (PEDOT). The polymer Schottky junction cells show superior surface passivation and open-circuit voltages compared to standard diffused junction cells with native oxide surfaces. External quantum efficiencies up to 88% were measured for these silicon nanowire/PEDOT solar cells further demonstrating excellent surface passivation. This process avoids high temperature processes which allows for low-cost substrates to be used. © 2010 IEEE.

  2. Effect of Surface Treated Silicon Dioxide Nanoparticles on Some Mechanical Properties of Maxillofacial Silicone Elastomer

    Directory of Open Access Journals (Sweden)

    Sara M. Zayed

    2014-01-01

    Full Text Available Current materials used for maxillofacial prostheses are far from ideal and there is a need for novel improved materials which mimic as close as possible the natural behavior of facial soft tissues. This study aimed to evaluate the effect of adding different concentrations of surface treated silicon dioxide nanoparticles (SiO2 on clinically important mechanical properties of a maxillofacial silicone elastomer. 147 specimens of the silicone elastomer were prepared and divided into seven groups (n=21. One control group was prepared without nanoparticles and six study groups with different concentrations of nanoparticles, from 0.5% to 3% by weight. Specimens were tested for tear strength (ASTM D624, tensile strength (ASTM D412, percent elongation, and shore A hardness. SEM was used to assess the dispersion of nano-SiO2 within the elastomer matrix. Data were analyzed by one-way ANOVA and Scheffe test (α=0.05. Results revealed significant improvement in all mechanical properties tested, as the concentration of the nanoparticles increased. This was supported by the results of the SEM. Hence, it can be concluded that the incorporation of surface treated SiO2 nanoparticles at concentration of 3% enhanced the overall mechanical properties of A-2186 silicone elastomer.

  3. Effects of thermomechanical processing on tensile and long-time creep behavior of Nb-1 percent Zr-0.1 percent C sheet

    Science.gov (United States)

    Titran, Robert H.; Uz, Mehmet

    1994-01-01

    Effects of thermomechanical processing on the mechanical properties of Nb-1 wt. percent Zr-0.1 wt. percent C, a candidate alloy for use in advanced space power systems, were investigated. Sheet bars were cold rolled into 1-mm thick sheets following single, double, or triple extrusion operations at 1900 K. All the creep and tensile specimens were given a two-step heat treatment 1 hr at 1755 K + 2 hr 1475 K prior to testing. Tensile properties were determined at 300 as well as at 1350 K. Microhardness measurements were made on cold rolled, heat treated, and crept samples. Creep tests were carried out at 1350 K and 34.5 MPa for times of about 10,000 to 19,000 hr. The results show that the number of extrusions had some effects on both the microhardness and tensile properties. However, the long-time creep behavior of the samples were comparable, and all were found to have adequate properties to meet the design requirements of advanced power systems regardless of thermomechanical history. The results are discussed in correlation with processing and microstructure, and further compared to the results obtained from the testing of Nb-1 wt. percent Zr and Nb-1 wt. percent Zr-0.06 wt. percent C alloys.

  4. Macular Effects of Silicone Oil Tamponade: Optical Coherence Tomography Findings During and After Silicone Oil Removal.

    Science.gov (United States)

    Lo, Danielle M; Flaxel, Christina J; Fawzi, Amani A

    2017-01-01

    To investigate retinal morphologic changes during silicone oil tamponade and after its removal using spectral domain OCT (SD-OCT) imaging. Retrospective review of 12 patients who underwent silicone oil tamponade for repair of retinal detachments. Macular OCT scans and volumetric thickness maps were examined qualitatively and quantitatively. Volumetric OCT revealed two distinct patterns during silicone oil: macular thickening (Group A) and macular thinning (Group B). In Group A, mean foveal thickness (507 ± 169 µm vs. 407 ± 163 µm, p = 0.003) and mean macular volume (11.6 ± 2.4 mm(3) vs. 9.9 ± 1.5 mm(3)) were significantly increased during tamponade compared to post-oil removal. Group B had significantly decreased mean foveal thickness (210 ± 38 µm vs. 276 ± 58 µm, p = 0.009) and macular volume (7.3 ± 1.8 mm(3) vs. 8.4 ± 1.8 mm(3)) during tamponade. Importantly, resolution of macular changes occurred without further intervention and was associated with improved visual acuity in both groups. Our series suggests that when faced with unexplained macular edema or macular thinning during tamponade, silicone oil removal alone can achieve resolution of these structural changes.

  5. CRED Cumulative Map of Percent Scleractinian Coral Cover at Lisianski Island, 2001-2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  6. Evaluation of three percent Aqueous Film Forming Foam (AFFF) concentrates as fire fighting agents

    Science.gov (United States)

    Jablonski, E. J.

    1981-04-01

    A large-scale fire test program involving 20,000-square foot JP-4 fuel fires was conducted to evaluate the fire suppression effectiveness and compatibility of 3 percent Aqueous Film Forming Foam (AFFF) agents in Air Force fire fighting vehicles. Three commercially available 3 percent AFFF concentrates were tested in accordance with military specification MIL-F-24385B. Test results are summarized in Appendix A. As a result of these tests, an updated Revision C to this MIL SPEC has been accomplished with new requirements for both 3 percent and 6 percent AFFF extinguishing agents.

  7. CRED Cumulative Map of Percent Scleractinian Coral Cover at Midway Atoll, 2002-04

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  8. CRED Cumulative Map of Percent Scleractinian Coral Cover at St. Rogatien West, 2001

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  9. CRED Cumulative Map of Percent Scleractinian Coral Cover at Niihau, 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  10. CRED Cumulative Map of Percent Scleractinian Coral Cover at Guam, 2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  11. CRED Cumulative Map of Percent Scleractinian Coral Cover at French Frigate Shoals

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  12. CRED Cumulative Map of Percent Scleractinian Coral Cover at Supply Reef

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  13. CRED Cumulative Map of Percent Scleractinian Coral Cover at Stingray Shoals

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  14. CRED Cumulative Map of Percent Scleractinian Coral Cover at Esmerelda Bank

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  15. CRED Cumulative Map of Percent Scleractinian Coral Cover at Santa Rosa Reef

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  16. CRED Cumulative Map of Percent Scleractinian Coral Cover at Necker Island, 2002-2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  17. CRED Cumulative Map of Percent Scleractinian Coral Cover at Palmyra Atoll, 2002-2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  18. CRED Cumulative Map of Percent Scleractinian Coral Cover at Maro Reef, 2001-2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  19. CRED Cumulative Map of Percent Scleractinian Coral Cover at Ta'u

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  20. CRED Cumulative Map of Percent Scleractinian Coral Cover at Ofu & Olosega

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  1. CRED Cumulative Map of Percent Scleractinian Coral Cover at Molokai, 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  2. CRED Cumulative Map of Percent Scleractinian Coral Cover at Pearl and Hermes Atoll, 2002-2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  3. CRED Cumulative Map of Percent Scleractinian Coral Cover at Raita Bank, 2001

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  4. CRED Cumulative Map of Percent Scleractinian Coral Cover at Johnston Atoll, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  5. CRED Cumulative Map of Percent Scleractinian Coral Cover at Farallon de Pajaros (Uracas)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  6. CRED Cumulative Map of Percent Scleractinian Coral Cover at Kauai, 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry.

  7. Environmentally benign silicon solar cell manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Tsuo, Y.S. [National Renewable Energy Lab., Golden, CO (United States); Gee, J.M. [Sandia National Labs., Albuquerque, NM (United States); Menna, P. [National Agency for New Technologies Energy and Environment, Portici (Italy); Strebkov, D.S.; Pinov, A.; Zadde, V. [Intersolarcenter, Moscow (Russian Federation)

    1998-09-01

    The manufacturing of silicon devices--from polysilicon production, crystal growth, ingot slicing, wafer cleaning, device processing, to encapsulation--requires many steps that are energy intensive and use large amounts of water and toxic chemicals. In the past two years, the silicon integrated-circuit (IC) industry has initiated several programs to promote environmentally benign manufacturing, i.e., manufacturing practices that recover, recycle, and reuse materials resources with a minimal consumption of energy. Crystalline-silicon solar photovoltaic (PV) modules, which accounted for 87% of the worldwide module shipments in 1997, are large-area devices with many manufacturing steps similar to those used in the IC industry. Obviously, there are significant opportunities for the PV industry to implement more environmentally benign manufacturing approaches. Such approaches often have the potential for significant cost reduction by reducing energy use and/or the purchase volume of new chemicals and by cutting the amount of used chemicals that must be discarded. This paper will review recent accomplishments of the IC industry initiatives and discuss new processes for environmentally benign silicon solar-cell manufacturing.

  8. Integrated silicon optoelectronics

    CERN Document Server

    Zimmermann, Horst

    2000-01-01

    'Integrated Silicon Optoelectronics'assembles optoelectronics and microelectronics The book concentrates on silicon as the major basis of modern semiconductor devices and circuits Starting from the basics of optical emission and absorption and from the device physics of photodetectors, the aspects of the integration of photodetectors in modern bipolar, CMOS, and BiCMOS technologies are discussed Detailed descriptions of fabrication technologies and applications of optoelectronic integrated circuits are included The book, furthermore, contains a review of the state of research on eagerly expected silicon light emitters In order to cover the topic of the book comprehensively, integrated waveguides, gratings, and optoelectronic power devices are included in addition Numerous elaborate illustrations promote an easy comprehension 'Integrated Silicon Optoelectronics'will be of value to engineers, physicists, and scientists in industry and at universities The book is also recommendable for graduate students speciali...

  9. Silicon microfabricated beam expander

    Science.gov (United States)

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

    2015-03-01

    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.

  10. Silicon microfabricated beam expander

    Energy Technology Data Exchange (ETDEWEB)

    Othman, A., E-mail: aliman@ppinang.uitm.edu.my; Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A. [Faculty of Electrical Engineering, Universiti Teknologi MARA Malaysia, 40450, Shah Alam, Selangor (Malaysia); Ain, M. F. [School of Electrical and Electronic Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, 14300,Nibong Tebal, Pulau Pinang (Malaysia)

    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.

  11. Neuromorphic Silicon Photonics

    CERN Document Server

    Tait, Alexander N; de Lima, Thomas Ferreira; Wu, Allie X; Nahmias, Mitchell A; Shastri, Bhavin J; Prucnal, Paul R

    2016-01-01

    We report first observations of an integrated analog photonic network, in which connections are configured by microring weight banks, as well as the first use of electro-optic modulators as photonic neurons. A mathematical isomorphism between the silicon photonic circuit and a continuous neural model is demonstrated through dynamical bifurcation analysis. Exploiting this isomorphism, existing neural engineering tools can be adapted to silicon photonic information processing systems. A 49-node silicon photonic neural network programmed using a "neural compiler" is simulated and predicted to outperform a conventional approach 1,960-fold in a toy differential system emulation task. Photonic neural networks leveraging silicon photonic platforms could access new regimes of ultrafast information processing for radio, control, and scientific computing.

  12. Electrochemical degradation of amorphous-silicon photovoltaic modules

    Science.gov (United States)

    Mon, G. R.; Ross, R. G., Jr.

    Techniques of module electrochemical corrosion research, developed during reliability studies of crystalline-silicon modules (C-Si), have been applied to this new investigation into amorphous-silicon (a-Si) module reliability. Amorphous-Si cells, encapsulated in the polymers polyvinyl butyral (PVB) and ethylene vinyl acetate (EVA), were exposed for more than 1200 hours in a controlled 85 C/85 percent RH environment, with a constant 500 volts applied between the cells and an aluminum frame. Plotting power output reduction versus charge transferred reveals that about 50 percent a-Si cell failures can be expected with the passage of 0.1 to 1.0 Coulomb/cm of cell-frame edge length; this threshold is somewhat less than that determined for C-Si modules.

  13. Behind the 29-percent limit. Solar researcher Martin Green presents ideas for inexpensive high-efficiency solar cells; Hinter der 29-Prozent-Grenze. Solarforscher Martin Green praesentiert Ideen fuer preiswerte Hocheffizienzsolarzellen

    Energy Technology Data Exchange (ETDEWEB)

    Kreutzmann, Anne

    2013-10-15

    Named after two physicists the Shockley-Queisser limit of 29 percent for today standard silicon solar cells is not reached in mass production. But the closer the industry comes to this physical limit, the more expensive is it to reach the final percentage points. A study by Martin Green, one of the world's leading researchers, and his team shows ways based on cheaper silicon solar cells, how the 29 percent limit can be overcome. [German] Die nach zwei Physikern benannte Shockley-Queisser-Grenze fuer heute uebliche Solarzellen aus Silizium von 29 Prozent ist in der Massenproduktion noch nicht erreicht. Aber je naeher die Industrie dieser physikalischen Grenze kommt, desto teurer wird es, die letzten Prozentpunkte zu schaffen. Eine Untersuchung von Martin Green, einem der weltweit fuehrenden Forscher, und seinem Team zeigt Wege auf, wie auf Grundlage billiger Siliziumsolarzellen die 29-Prozent-Grenze ueberwunden werden kann.

  14. The DELPHI silicon tracker

    CERN Document Server

    Pernegger, H

    1997-01-01

    The DELPHI collaboration has upgraded the Silicon Vertex Detector in order to cope with the physics requirements for LEP200. The new detector consists of a barrel section with three layers of microstrip detectors and a forward extension made of hybrid pixel and large pitch strip detectors. The layout of the detector and the techniques used for the different parts of the new silicon detector shall be described.

  15. Dual detection biosensor based on porous silicon substrate

    Energy Technology Data Exchange (ETDEWEB)

    Simion, Monica, E-mail: moni304ro@yahoo.com; Kusko, Mihaela; Mihalache, Iuliana; Brăgaru, Adina

    2013-11-20

    Due to the high surface-to-volume ratio (hundreds of m{sup 2}/cm{sup 3}) porous silicon became during the last years a good candidate material as substrate for biosensor application. Moreover, the versatility of surface chemistry allows different functionalization approaches and large number of molecules to be captured on well-defined areas. This paper reports a dual detection method for protein recognition processes developed on different nanostructured porous silicon (PS) substrates, based on using two complementary spectroscopic techniques: fluorescence and electrochemical impedance. The structures were tested for biomolecular recognition – biotin–strepavidin couples – in order to achieve an optimum surface for protein's immobilizations. Comparative analyses of the attachment degree and preservation of the biomolecules activity on the porous silicon surfaces and silicon slides are also described.

  16. Microcellular foaming of silicone rubber with supercritical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Hong, In-Kwon; Lee, Sangmook [Dankook University, Youngin (Korea, Republic of)

    2014-01-15

    In spite of great concern on the industrial application of microcellular silicone rubber foams, such as in electric and medical devices, only a few works can be found about the foaming of silicone rubber. In this study, microcellular silicone rubber foams with a cell size of 12 µm were successfully prepared with curing by heat and foaming by supercritical CO{sub 2} as a green blowing agent. The microcellular silicone rubber foams exhibited a well-defined cell structure and a uniform cell size distribution. The crosslinking and foaming of silicone rubber was carried out separately. After foaming, the silicone rubber foam was cross-linked again to stabilize the foam structure and further improve its mechanical properties. Foaming process of cross-linked silicone rubber should be designed carefully based on the viscoelastic properties because of its elastic volume recovery in the atmosphere. The basic crosslinking condition for small cell size and high cell density was obtained after investigating the rheological behavior during crosslinking.

  17. Preparation of electrochemically active silicon nanotubes in highly ordered arrays

    Directory of Open Access Journals (Sweden)

    Tobias Grünzel

    2013-10-01

    Full Text Available Silicon as the negative electrode material of lithium ion batteries has a very large capacity, the exploitation of which is impeded by the volume changes taking place upon electrochemical cycling. A Si electrode displaying a controlled porosity could circumvent the difficulty. In this perspective, we present a preparative method that yields ordered arrays of electrochemically competent silicon nanotubes. The method is based on the atomic layer deposition of silicon dioxide onto the pore walls of an anodic alumina template, followed by a thermal reduction with lithium vapor. This thermal reduction is quantitative, homogeneous over macroscopic samples, and it yields amorphous silicon and lithium oxide, at the exclusion of any lithium silicides. The reaction is characterized by spectroscopic ellipsometry for thin silica films, and by nuclear magnetic resonance and X-ray photoelectron spectroscopy for nanoporous samples. After removal of the lithium oxide byproduct, the silicon nanotubes can be contacted electrically. In a lithium ion electrolyte, they then display the electrochemical waves also observed for other bulk or nanostructured silicon systems. The method established here paves the way for systematic investigations of how the electrochemical properties (capacity, charge/discharge rates, cyclability of nanoporous silicon negative lithium ion battery electrode materials depend on the geometry.

  18. Highly sensitive and reproducible silicon-based surface-enhanced Raman scattering sensors for real applications.

    Science.gov (United States)

    Wang, Houyu; Jiang, Xiangxu; He, Yao

    2016-08-15

    During the past few decades, thanks to silicon nanomaterials' outstanding electronic/optical/mechanical properties, large surface-to-volume ratio, abundant surface chemistry, facile tailorability and good compatibility with modern semiconductor industry, different dimensional silicon nanostructures have been widely employed for rationally designing and fabricating high-performance surface-enhanced Raman scattering (SERS) sensors for the detection of various chemical and biological species. Among these, two-dimensional silicon nanostructures made of metal nanoparticle-modified silicon wafers and three-dimensional silicon nanostructures made of metal nanoparticle-decorated SiNW arrays are of particular interest, and have been extensively exploited as promising silicon-based SERS-active substrates for the construction of high-performance SERS sensors. With an aim to retrospect these important and exciting achievements, we herein focus on reviewing recent representative studies on silicon-based SERS sensors for sensing applications from a broad perspective and possible future direction, promoting readers' awareness of these novel powerful silicon-based SERS sensing technologies. Firstly, we summarize the two unique merits of silicon-based SERS sensors, and those are high sensitivity and good reproducibility. Next, we present recent advances of two- and three-dimensional silicon-based SERS sensors, especially for real applications. Finally, we discuss the major challenges and prospects for the development of silicon-based SERS sensors.

  19. Inorganic Glue Enabling High Performance of Silicon Particles as Lithium Ion Battery Anode

    KAUST Repository

    Cui, Li-Feng

    2011-01-01

    Silicon, as an alloy-type anode material, has recently attracted lots of attention because of its highest known Li+ storage capacity (4200 mAh/g). But lithium insertion into and extraction from silicon are accompanied by a huge volume change, up to 300, which induces a strong strain on silicon and causes pulverization and rapid capacity fading due to the loss of the electrical contact between part of silicon and current collector. Silicon nanostructures such as nanowires and nanotubes can overcome the pulverization problem, however these nano-engineered silicon anodes usually involve very expensive processes and have difficulty being applied in commercial lithium ion batteries. In this study, we report a novel method using amorphous silicon as inorganic glue replacing conventional polymer binder. This inorganic glue method can solve the loss of contact issue in conventional silicon particle anode and enables successful cycling of various sizes of silicon particles, both nano-particles and micron particles. With a limited capacity of 800 mAh/g, relatively large silicon micron-particles can be stably cycled over 200 cycles. The very cheap production of these silicon particle anodes makes our method promising and competitive in lithium ion battery industry. © 2011 The Electrochemical Society.

  20. Oxygen defect processes in silicon and silicon germanium

    KAUST Repository

    Chroneos, A.

    2015-06-18

    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.

  1. Silicon-Based Light Sources for Silicon Integrated Circuits

    Directory of Open Access Journals (Sweden)

    L. Pavesi

    2008-01-01

    Full Text Available Silicon the material per excellence for electronics is not used for sourcing light due to the lack of efficient light emitters and lasers. In this review, after having introduced the basics on lasing, I will discuss the physical reasons why silicon is not a laser material and the approaches to make it lasing. I will start with bulk silicon, then I will discuss silicon nanocrystals and Er3+ coupled silicon nanocrystals where significant advances have been done in the past and can be expected in the near future. I will conclude with an optimistic note on silicon lasing.

  2. Oxygen defect processes in silicon and silicon germanium

    Energy Technology Data Exchange (ETDEWEB)

    Chroneos, A., E-mail: alexander.chroneos@imperial.ac.uk [Faculty of Engineering and Computing, Coventry University, Priory Street, Coventry CV1 5FB (United Kingdom); Department of Materials, Imperial College London, London SW7 2BP (United Kingdom); Sgourou, E. N.; Londos, C. A. [Solid State Section, Physics Department, University of Athens, Panepistimiopolis, Zografos, 157 84 Athens (Greece); Schwingenschlögl, U. [PSE Division, KAUST, Thuwal 23955-6900 (Saudi Arabia)

    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.

  3. Amorphous silicon crystalline silicon heterojunction solar cells

    CERN Document Server

    Fahrner, Wolfgang Rainer

    2013-01-01

    Amorphous Silicon/Crystalline Silicon Solar Cells deals with some typical properties of heterojunction solar cells, such as their history, the properties and the challenges of the cells, some important measurement tools, some simulation programs and a brief survey of the state of the art, aiming to provide an initial framework in this field and serve as a ready reference for all those interested in the subject. This book helps to "fill in the blanks" on heterojunction solar cells. Readers will receive a comprehensive overview of the principles, structures, processing techniques and the current developmental states of the devices. Prof. Dr. Wolfgang R. Fahrner is a professor at the University of Hagen, Germany and Nanchang University, China.

  4. Femtosecond Laser Crystallization of Boron-doped Amorphous Hydrogenated Silicon Films

    Directory of Open Access Journals (Sweden)

    P.D. Rybalko

    2016-10-01

    Full Text Available Crystallization of amorphous hydrogenated silicon films with femtosecond laser pulses is one of the promising ways to produce nanocrystalline silicon for photovoltaics. The structure of laser treated films is the most important factor determining materials' electric and photoelectric properties. In this work we investigated the effect of femtosecond laser irradiation of boron doped amorphous hydrogenated silicon films with different fluences on crystalline volume fraction and electrical properties of this material. A sharp increase of conductivity and essential decrease of activation energy of conductivity temperature dependences accompany the crystallization process. The results obtained are explained by increase of boron doping efficiency in crystalline phase of modified silicon film.

  5. 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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. Silicon-on ceramic process. Silicon sheet growth and device development for the large-area silicon sheet and cell development tasks of the low-cost solar array project. Quarterly report No. 12, April 2, 1979-June 29, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, P.W.; Zook, J.D.; Heaps, J.D.; Grung, B.L.; Koepke, B.; Schuldt, S.B.

    1979-07-31

    The objective of this research program is to investigate the technical and economic feasibility of producing solar-cell-quality sheet silicon. We plan to do this by coating one surface of carbonized ceramic substrates with a thin layer of large-grain polycrystalline silicon from the melt. During the quarter, significant progress was demonstrated in several areas: (1) a 10-cm/sup 2/ cell having 9.9 percent conversion efficiency (AM1, AR) was fabricated; (2) the Honeywall-sponsored SCIM coating development succeeded in producing a 225-cm/sup 2/ layer of sheet silicon (18 inches x 2 inches); and (3) 100 ..mu..m-thick coatings at pull speed of 0.15 cm/sec wer$obta9ned, although apoproximately 50 percent of the layer exhibited dendritic growth. Other results and accomplishments during the quarter are reported in detail. (WHK)

  7. Does Ending Affirmative Action in College Admissions Lower the Percent of Minority Students Applying to College?

    Science.gov (United States)

    Dickson, Lisa M.

    2006-01-01

    The purpose of this study is to determine how ending affirmative action in public colleges in Texas affected the percent of minority high school graduates applying to college. I find the end of affirmative action significantly lowered the percent of Hispanic students applying to college by 1.6 percentage points and significantly lowered the…

  8. Effect of Physical Activity on BMI and Percent Body Fat of Chinese Girls.

    Science.gov (United States)

    Fu, Frank H.; And Others

    1995-01-01

    This study investigated the effect of regular physical activity on body mass index (BMI) and percent body fat of Chinese girls grouped by age and physical activity patterns. Measurements of skinfold, height, and weight, and BMI calculations, found differences in BMI and percent body fat between active and inactive girls. (SM)

  9. Note: fast and reliable fracture strain extraction technique applied to silicon at nanometer scale.

    Science.gov (United States)

    Passi, Vikram; Bhaskar, Umesh; Pardoen, Thomas; Sodervall, Ulf; Nilsson, Bengt; Petersson, Goran; Hagberg, Mats; Raskin, Jean-Pierre

    2011-11-01

    Simple fabrication process and extraction procedure to determine the fracture strain of monocrystalline silicon are demonstrated. Nanowires/nanoribbons in silicon are fabricated and subjected to uniaxial tensile stress along the complete length of the beams. Large strains up to 5% are measured for nanowires presenting a cross section of 50 nm × 50 nm and a length of 2.5 μm. An increase in fracture strain for silicon nanowires (NWs) with the downscaling of their volume is observed, highlighting the reduction of the defects probability as volume is decreased.

  10. Low-cost solar array project task 1: Silicon material. Gaseous melt replenishment system

    Science.gov (United States)

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

    1980-01-01

    The operation of a silicon production technique was demonstrated. The essentials of the method comprise chemical vapor deposition of silicon, by hydrogen reduction of chlorosilanes, on the inside of a quartz reaction vessel having large internal surface area. The system was designed to allow successive deposition-melting cycles, with silicon removal being accomplished by discharging the molten silicon. The liquid product would be suitable for transfer to a crystal growth process, casting into solid form, or production of shots. A scaled-down prototype reactor demonstrated single pass conversion efficiency of 20 percent and deposition rates and energy consumption better than conventional Siemens reactors, via deposition rates of 365 microns/hr. and electrical consumption of 35 Kwhr/kg of silicon produced.

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

    Science.gov (United States)

    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.

  12. Selectively accelerated lithium ion transport to silicon anodes via an organogel binder

    Science.gov (United States)

    Hwang, Chihyun; Cho, Yoon-Gyo; Kang, Na-Ri; Ko, Younghoon; Lee, Ungju; Ahn, Dongjoon; Kim, Ju-Young; Kim, Young-Jin; Song, Hyun-Kon

    2015-12-01

    Silicon, a promising high-capacity anode material of lithium ion batteries, suffers from its volume expansion leading to pulverization and low conductivities, showing capacity decay during cycling and low capacities at fast charging and discharging. In addition to popular active-material-modifying strategies, building lithium-ion-rich environments around silicon surface is helpful in enhancing unsatisfactory performances of silicon anodes. In this work, we accelerated lithium ion transport to silicon surface by using an organogel binder to utilize the electroactivity of silicon in a more efficient way. The cyanoethyl polymer (PVA-CN), characterized by high lithium ion transference number as well as appropriate elastic modulus with strong adhesion, enhanced cycle stability of silicon anodes with high coulombic efficiency even at high temperature (60 °C) as well as at fast charging/discharging rates.

  13. Performance improvement of silicon solar cells by nanoporous silicon coating

    Directory of Open Access Journals (Sweden)

    Dzhafarov T. D.

    2012-04-01

    Full Text Available In the present paper the method is shown to improve the photovoltaic parameters of screen-printed silicon solar cells by nanoporous silicon film formation on the frontal surface of the cell using the electrochemical etching. The possible mechanisms responsible for observed improvement of silicon solar cell performance are discussed.

  14. Spintronics: Silicon takes a spin

    NARCIS (Netherlands)

    Jansen, Ron

    2007-01-01

    An efficient way to transport electron spins from a ferromagnet into silicon essentially makes silicon magnetic, and provides an exciting step towards integration of magnetism and mainstream semiconductor electronics.

  15. Single-cell concepts for obtaining photovoltaic conversion efficiency over 30 percent

    Science.gov (United States)

    Fan, John C. C.

    1985-01-01

    Although solar photovoltaic conversion efficiencies over 30 percent (one sun, AM1) can be expected for multiple-cell configurations using spectral splitting techniques, the highest practical single-cell conversion efficiency that can be attained using present concepts is estimated to be about 27-28 percent. To achieve conversion efficiencies above 30 percent using single-cell configurations it will be necessary to employ different concepts, such as spectral compression and broad-band detection. The implementation of these concepts would require major breakthroughs that are not anticipated in the near future.

  16. Thick silicon growth techniques

    Science.gov (United States)

    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.

  17. The electrophotonic silicon biosensor

    Science.gov (United States)

    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.

  18. Floating Silicon Method

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. Silicon containing copolymers

    CERN Document Server

    Amiri, Sahar; Amiri, Sanam

    2014-01-01

    Silicones have unique properties including thermal oxidative stability, low temperature flow, high compressibility, low surface tension, hydrophobicity and electric properties. These special properties have encouraged the exploration of alternative synthetic routes of well defined controlled microstructures of silicone copolymers, the subject of this Springer Brief. The authors explore the synthesis and characterization of notable block copolymers. Recent advances in controlled radical polymerization techniques leading to the facile synthesis of well-defined silicon based thermo reversible block copolymers?are described along with atom transfer radical polymerization (ATRP), a technique utilized to develop well-defined functional thermo reversible block copolymers. The brief also focuses on Polyrotaxanes and their great potential as stimulus-responsive materials which produce poly (dimethyl siloxane) (PDMS) based thermo reversible block copolymers.

  20. Silicon photonics: optical modulators

    Science.gov (United States)

    Reed, G. T.; Gardes, F. Y.; Hu, Youfang; Thomson, D.; Lever, L.; Kelsall, R.; Ikonic, Z.

    2010-01-01

    Silicon Photonics has the potential to revolutionise a whole raft of application areas. Currently, the main focus is on various forms of optical interconnects as this is a near term bottleneck for the computing industry, and hence a number of companies have also released products onto the market place. The adoption of silicon photonics for mass production will significantly benefit a range of other application areas. One of the key components that will enable silicon photonics to flourish in all of the potential application areas is a high performance optical modulator. An overview is given of the major Si photonics modulator research that has been pursued at the University of Surrey to date as well as a worldwide state of the art showing the trend and technology available. We will show the trend taken toward integration of optical and electronic components with the difficulties that are inherent in such a technology.

  1. Integrated Silicon Optoelectronics

    CERN Document Server

    Zimmermann, Horst K

    2010-01-01

    Integrated Silicon Optoelectronics synthesizes topics from optoelectronics and microelectronics. The book concentrates on silicon as the major base of modern semiconductor devices and circuits. Starting from the basics of optical emission and absorption, as well as from the device physics of photodetectors, the aspects of the integration of photodetectors in modern bipolar, CMOS, and BiCMOS technologies are discussed. Detailed descriptions of fabrication technologies and applications of optoelectronic integrated circuits are included. The book, furthermore, contains a review of the newest state of research on eagerly anticipated silicon light emitters. In order to cover the topics comprehensively, also included are integrated waveguides, gratings, and optoelectronic power devices. Numerous elaborate illustrations facilitate and enhance comprehension. This extended edition will be of value to engineers, physicists, and scientists in industry and at universities. The book is also recommended to graduate student...

  2. Microgravity silicon zoning investigation

    Science.gov (United States)

    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.

  3. The LHCb Silicon Tracker

    Energy Technology Data Exchange (ETDEWEB)

    Tobin, Mark, E-mail: Mark.Tobin@epfl.ch

    2016-09-21

    The LHCb experiment is dedicated to the study of heavy flavour physics at the Large Hadron Collider (LHC). The primary goal of the experiment is to search for indirect evidence of new physics via measurements of CP violation and rare decays of beauty and charm hadrons. The LHCb detector has a large-area silicon micro-strip detector located upstream of a dipole magnet, and three tracking stations with silicon micro-strip detectors in the innermost region downstream of the magnet. These two sub-detectors form the LHCb Silicon Tracker (ST). This paper gives an overview of the performance and operation of the ST during LHC Run 1. Measurements of the observed radiation damage are shown and compared to the expectation from simulation.

  4. Neuromorphic silicon neuron circuits

    Directory of Open Access Journals (Sweden)

    Giacomo eIndiveri

    2011-05-01

    Full Text Available 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.

  5. The electrophotonic silicon biosensor

    Science.gov (United States)

    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

  6. Silicon microphones - a Danish perspective

    DEFF Research Database (Denmark)

    Bouwstra, Siebe; Storgaard-Larsen, Torben; Scheeper, Patrick

    1998-01-01

    Two application areas of microphones are discussed, those for precision measurement and those for hearing instruments. Silicon microphones are under investigation for both areas, and Danish industry plays a key role in both. The opportunities of silicon, as well as the challenges and expectations......, are discussed. For precision measurement the challenge for silicon is large, while for hearing instruments silicon seems to be very promising....

  7. Prices Up and Volumes Stable

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    2011 First Half China Garment Industry Report Exports Grew at a Slower Pace China Customs reported the garment & accessories export value of $51.286 billion for the first five months of this year, up 23.12% y/y, accounting for 56.28 percent of the total, 5% lower than the previous year’s points.Despite sales prices increase, sales volume remain stable. From Jan. to May

  8. Silicon Field Emission Arrays Coated with CNx Thin Films

    Institute of Scientific and Technical Information of China (English)

    Chen Min-gan; Chen Ming-an; Li Jin-chai; Li Jin-chai; Liu Chuan-sheng; Liu Chuan-sheng; Ma You-peng; Ma You-peng; Lu Xian-feng; Lu Xian-feng; Ye Ming-sheng; Ye Ming-sheng

    2003-01-01

    Arrays of silicon micro-tips were made by etching the p-type (1 0 0) silicon wafers which had SiO2 masks with alkaline solution. The density of the micro-tips is 2 ×104 cm-2. The Scanning Electron Microscope (SEM) photos showed that the tips in these arrays are uniform and orderly.The CNx thin film, with the thickness of 1.27μm was deposited on the silicon micro-tip arrays by using the middle frequency magnetron sputtering technology. The SEM photos showed that the films on the tips are smoothly without particles. Keeping the sharpness of the tips will benefit the properties of field emission. The X-ray photoelectron spectrum (XPS) showed that carbon, nitrogen and oxygen are the three major elements in the surfaces of the films. The percents of them are C: 69.5 %, N: 12.6 % and O: 17.9 %. The silicon arrays coated with CNx thin films had shown a good field emission characterization. The emission current intensity reached 3.2 mA/cm2 at 32.8 V/μm, so it can be put into use. The result showed that the silicon arrays coated with CNx thin films are likely to be good field emission cathode.The preparation and the characterization of the samples were discussed in detail.

  9. Silicon Field Emission Arrays Coated with CNx Thin Films

    Institute of Scientific and Technical Information of China (English)

    ChertMing-an; LiJin-chai; LiuChuan-sheng; MaYou-peng; LuXlan-feng; YeMing-sheng

    2003-01-01

    Arrays of silicon micro-tips were made by etching the p-type (1 0 0) silicon wafers which had SiO2 masks with alkaline solution. The density of the micro-tips is 2 ×104 cm-2. The Scanning Electron Microscope (SEM) photos showed that the tips in these arrays are uniform and orderly.The CNx thin film, with the thickness of 1.27μm was deposited on the silicon micro-tip arrays by using the middle frequency magnetron sputtering technology. The SEM photos showed that the films on the tips are smoothly without particles. Keeping the sharpness of the tips will benefit the properties of field emission. The X-ray photoelectron spectrum (XPS) showed that carbon, nitrogen and oxygen are the three major elements in the surfaces of the films. The percents of them are C: 69.5 %, N: 12. 6 % and O: 17.9 %. The silicon arrays coated with CNx thin films had shown a good field emission characterization. The emission current intensity reached 3. 2 mA/cm2 at 32.8 V/μm, so it can be put into use. The result showed that the silicon arrays coated with CNx thin films are likely to be good field emission cathode.The preparation and the characterization of the samples were discussed in detail.

  10. CMS silicon tracker developments

    Energy Technology Data Exchange (ETDEWEB)

    Civinini, C. E-mail: carlo.civinini@fi.infn.it; Albergo, S.; Angarano, M.; Azzi, P.; Babucci, E.; Bacchetta, N.; Bader, A.; Bagliesi, G.; Basti, A.; Biggeri, U.; Bilei, G.M.; Bisello, D.; Boemi, D.; Bosi, F.; Borrello, L.; Bozzi, C.; Braibant, S.; Breuker, H.; Bruzzi, M.; Buffini, A.; Busoni, S.; Candelori, A.; Caner, A.; Castaldi, R.; Castro, A.; Catacchini, E.; Checcucci, B.; Ciampolini, P.; Creanza, D.; D' Alessandro, R.; Da Rold, M.; Demaria, N.; De Palma, M.; Dell' Orso, R.; Della Marina, R.D.R.; Dutta, S.; Eklund, C.; Feld, L.; Fiore, L.; Focardi, E.; French, M.; Freudenreich, K.; Frey, A.; Fuertjes, A.; Giassi, A.; Giorgi, M.; Giraldo, A.; Glessing, B.; Gu, W.H.; Hall, G.; Hammarstrom, R.; Hebbeker, T.; Honma, A.; Hrubec, J.; Huhtinen, M.; Kaminsky, A.; Karimaki, V.; Koenig, St.; Krammer, M.; Lariccia, P.; Lenzi, M.; Loreti, M.; Luebelsmeyer, K.; Lustermann, W.; Maettig, P.; Maggi, G.; Mannelli, M.; Mantovani, G.; Marchioro, A.; Mariotti, C.; Martignon, G.; Evoy, B. Mc; Meschini, M.; Messineo, A.; Migliore, E.; My, S.; Paccagnella, A.; Palla, F.; Pandoulas, D.; Papi, A.; Parrini, G.; Passeri, D.; Pieri, M.; Piperov, S.; Potenza, R.; Radicci, V.; Raffaelli, F.; Raymond, M.; Santocchia, A.; Schmitt, B.; Selvaggi, G.; Servoli, L.; Sguazzoni, G.; Siedling, R.; Silvestris, L.; Starodumov, A.; Stavitski, I.; Stefanini, G.; Surrow, B.; Tempesta, P.; Tonelli, G.; Tricomi, A.; Tuuva, T.; Vannini, C.; Verdini, P.G.; Viertel, G.; Xie, Z.; Yahong, Li; Watts, S.; Wittmer, B

    2002-01-21

    The CMS Silicon tracker consists of 70 m{sup 2} of microstrip sensors which design will be finalized at the end of 1999 on the basis of systematic studies of device characteristics as function of the most important parameters. A fundamental constraint comes from the fact that the detector has to be operated in a very hostile radiation environment with full efficiency. We present an overview of the current results and prospects for converging on a final set of parameters for the silicon tracker sensors.

  11. CMS silicon tracker developments

    CERN Document Server

    Civinini, C; Angarano, M M; Azzi, P; Babucci, E; Bacchetta, N; Bader, A; Bagliesi, G; Basti, A; Biggeri, U; Bilei, G M; Bisello, D; Boemi, D; Bosi, F; Borrello, L; Bozzi, C; Braibant, S; Breuker, Horst; Bruzzi, Mara; Buffini, A; Busoni, S; Candelori, A; Caner, A; Castaldi, R; Castro, A; Catacchini, E; Checcucci, B; Ciampolini, P; Creanza, D; D'Alessandro, R; Da Rold, M; Demaria, N; De Palma, M; Dell'Orso, R; Della Marina, R; Dutta, S; Eklund, C; Feld, L; Fiore, L; Focardi, E; French, M; Freudenreich, Klaus; Frey, A; Fürtjes, A; Giassi, A; Giorgi, M; Giraldo, A; Glessing, B; Gu, W H; Hall, G; Hammarström, R; Hebbeker, T; Honma, A; Hrubec, Josef; Huhtinen, M; Kaminski, A; Karimäki, V; König, S; Krammer, Manfred; Lariccia, P; Lenzi, M; Loreti, M; Lübelsmeyer, K; Lustermann, W; Mättig, P; Maggi, G; Mannelli, M; Mantovani, G C; Marchioro, A; Mariotti, C; Martignon, G; McEvoy, B; Meschini, M; Messineo, A; Migliore, E; My, S; Paccagnella, A; Palla, Fabrizio; Pandoulas, D; Papi, A; Parrini, G; Passeri, D; Pieri, M; Piperov, S; Potenza, R; Radicci, V; Raffaelli, F; Raymond, M; Santocchia, A; Schmitt, B; Selvaggi, G; Servoli, L; Sguazzoni, G; Siedling, R; Silvestris, L; Starodumov, Andrei; Stavitski, I; Stefanini, G; Surrow, B; Tempesta, P; Tonelli, G; Tricomi, A; Tuuva, T; Vannini, C; Verdini, P G; Viertel, Gert M; Xie, Z; Li Ya Hong; Watts, S; Wittmer, B

    2002-01-01

    The CMS Silicon tracker consists of 70 m/sup 2/ of microstrip sensors which design will be finalized at the end of 1999 on the basis of systematic studies of device characteristics as function of the most important parameters. A fundamental constraint comes from the fact that the detector has to be operated in a very hostile radiation environment with full efficiency. We present an overview of the current results and prospects for converging on a final set of parameters for the silicon tracker sensors. (9 refs).

  12. Irradiation Defects in Silicon Crystal

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The application of irradiation in silicon crystal is introduced.The defects caused by irradiation are reviewed and some major ways of studying defects in irradiated silicon are summarized.Furthermore the problems in the investigation of irradiated silicon are discussed as well as its properties.

  13. EnviroAtlas - Woodbine, IA - Estimated Percent Tree Cover Along Walkable Roads

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset estimates tree cover along walkable roads. The road width is estimated for each road and percent tree cover is calculated in a 8.5 meter...

  14. EnviroAtlas - New Bedford, MA - Estimated Percent Tree Cover Along Walkable Roads

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset estimates tree cover along walkable roads. The road width is estimated for each road and percent tree cover is calculated in a 8.5 meter...

  15. EnviroAtlas - Durham, NC - Estimated Percent Tree Cover Along Walkable Roads

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset estimates tree cover along walkable roads. The road width is estimated for each road and percent tree cover is calculated in a 8.5 meter...

  16. EnviroAtlas - Austin, TX - Estimated Percent Tree Cover Along Walkable Roads

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset estimates tree cover along walkable roads. The road width is estimated for each road and percent tree cover is calculated in a 8.5 meter...

  17. EnviroAtlas - Fresno, CA - Estimated Percent Tree Cover Along Walkable Roads

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset estimates tree cover along walkable roads. The road width is estimated for each road and percent tree cover is calculated in a 8.5 meter...

  18. EnviroAtlas - Paterson, NJ - Estimated Percent Tree Cover Along Walkable Roads

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset estimates tree cover along walkable roads. The road width is estimated for each road and percent tree cover is calculated in a 8.5 meter...

  19. EnviroAtlas - Portland, OR - Estimated Percent Tree Cover Along Walkable Roads

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset estimates tree cover along walkable roads. The road width is estimated for each road and percent tree cover is calculated in a 8.5 meter...

  20. EnviroAtlas - Memphis, TN - Estimated Percent Tree Cover Along Walkable Roads

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset estimates tree cover along walkable roads. The road width is estimated for each road and percent tree cover is calculated in a 8.5 meter...

  1. EnviroAtlas - Tampa, FL - Estimated Percent Tree Cover Along Walkable Roads

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset estimates tree cover along walkable roads. The road width is estimated for each road and percent tree cover is calculated in a 8.5 meter...

  2. EnviroAtlas - Milwaukee, WI - Estimated Percent Tree Cover Along Walkable Roads

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset estimates tree cover along walkable roads. The road width is estimated for each road and percent tree cover is calculated in a 8.5 meter...

  3. 20 percent lower lung cancer mortality with low-dose CT vs chest X-ray

    Science.gov (United States)

    Scientists have found a 20 percent reduction in deaths from lung cancer among current or former heavy smokers who were screened with low-dose helical computed tomography (CT) versus those screened by chest X-ray.

  4. EnviroAtlas - Cleveland, OH - Estimated Percent Tree Cover Along Walkable Roads

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset estimates tree cover along walkable roads. The road width is estimated for each road and percent tree cover is calculated in a 8.5 meter...

  5. EnviroAtlas - Green Bay, WI - Estimated Percent Tree Cover Along Walkable Roads

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset estimates tree cover along walkable roads. The road width is estimated for each road and percent tree cover is calculated in a 8.5 meter...

  6. EnviroAtlas Estimated Percent Tree Cover Along Walkable Roads Web Service

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset estimates tree cover along walkable roads. The road width is estimated for each road and percent tree cover is calculated in a 8.5 meter...

  7. Map of percent scleractinian coral cover and sand along camera tow tracks in west Hawaii

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral and sand overlaid on bathymetry and landsat imagery northwest...

  8. Map of percent scleractinian coral cover along camera tow tracks in west Hawaii

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This map displays optical validation observation locations and percent coverage of scleractinian coral overlaid on bathymetry and landsat imagery northwest of...

  9. EnviroAtlas - New York, NY - Estimated Percent Tree Cover Along Walkable Roads

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset estimates tree cover along walkable roads. The road width is estimated for each road and percent tree cover is calculated in a 8.5 meter...

  10. EnviroAtlas - Minneapolis/St. Paul, MN - Estimated Percent Tree Cover Along Walkable Roads

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset estimates tree cover along walkable roads. The road width is estimated for each road and percent tree cover is calculated in a 8.5 meter...

  11. Stellwagen Bank bathymetry - Percent slope derived from 5-meter bathymetric contour lines

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Percent slope of Stellwagen Bank bathymetry. Raster derived from 5-meter bathymetric contour lines (Quads 1-18). Collected on surveys carried out in 4 cruises 1994 -...

  12. EnviroAtlas - Pittsburgh, PA - Estimated Percent Tree Cover Along Walkable Roads

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset estimates tree cover along walkable roads. The road width is estimated for each road and percent tree cover is calculated in a 8.5 meter...

  13. Riparian vegetation abundance (percent cover) in the Elwha River estuary, Washington, in 2007 and 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This portion of the data release presents riparian plant species abundance (percent cover) data from plots sampled in the Elwha River estuary, Washington, in 2007...

  14. EnviroAtlas - Phoenix, AZ - Estimated Percent Tree Cover Along Walkable Roads

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset estimates tree cover along walkable roads. The road width is estimated for each road and percent tree cover is calculated in a 8.5 meter...

  15. EnviroAtlas - Des Moines, IA - Estimated Percent Tree Cover Along Walkable Roads

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset estimates tree cover along walkable roads. The road width is estimated for each road and percent tree cover is calculated in a 8.5 meter...

  16. EnviroAtlas - Portland, ME - Estimated Percent Tree Cover Along Walkable Roads

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset estimates tree cover along walkable roads. The road width is estimated for each road and percent tree cover is calculated in a 8.5 meter...

  17. THE CLINICAL SIGNIFICANCE OF PERCENT FREE PSA IN DIFFERENTIATING PROSTATE CANCER AND BENIGN PROSTATE HYPERPLASIA

    Institute of Scientific and Technical Information of China (English)

    王子明; 张鹏; 种铁; 赵丽华

    2004-01-01

    Objective To evaluate using prostate specific antigen (PSA) and percent free PSA(fPSA) for the diagnosis of prostate cancer(Pca) and benign prostate hyperplasia(BPH). Methods 315 men with BPH and 55 men with Pca were randomly chosen, serum fPSA and total PSA were determined by ELISA and then we compared the sensitivity and specificity of PSA and percent fPSA for the diagnosis of Pca. Results While using PSA and percent fPSA for the diagnosis of prostate cancer, the sensitivity was similar (89.8% vs. 94.5%, P>0.05), but the specificity was significanty different (52.7% vs. 89.8%, P<0.005). Conclusions Using percent fPSA might decrease false-positive and avoid 37.1% negative biopsies as compared with PSA, it is very valuable for the diagnosis of Pca.

  18. EnviroAtlas - Percent Urban Land Cover by 12-Digit HUC for the Conterminous United States

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset estimates the percent urban land for each 12-digit hydrologic unit code (HUC) in the conterminous United States. For the purposes of this...

  19. Silicon Deep Etching Techniques for MEMS Devices

    Institute of Scientific and Technical Information of China (English)

    WU Ying; OU Yi-hong; JIANG Yong-qing; LI Bin

    2003-01-01

    Silicon deep etching technique is the key fabrication step in the development of MEMS. The mask selectivity and the lateral etching control are the two primary factors that decide the result of deep etching process. These two factors are studied in this paper. The experimental results show that the higher selectivity can be gotten when F- gas is used as etching gas and Al is introduced as mask layer. The lateral etching problems can be solved by adjusting the etching condition, such as increasing the RF power, changing the gas composition and flow volume of etching machine.

  20. Sinopec's Net Profit Slumps 35.04 Percent in Q1

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Sinopec Corp., Asia's largest oil refiner, announced that its net profit slumped 35.04 percent year on year to 13.41 billion yuan (US$2.13 billion) in the first quarter amid rising operation costs and diminishing profit margins. Business earnings during the period dropped 28.99 percent year on year to 21.81 billion yuan, the company said in its quarterly report filed with the Shanghai Stock Exchange.

  1. WHK Student Internship Enrollment, Mentor Participation Up More than 50 Percent | Poster

    Science.gov (United States)

    By Nancy Parrish, Staff Writer The Werner H. Kirsten Student Internship Program (WHK SIP) has enrolled the largest class ever for the 2013–2014 academic year, with 66 students and 50 mentors. This enrollment reflects a 53 percent increase in students and a 56 percent increase in mentors, compared to 2012–2013 (43 students and 32 mentors), according to Julie Hartman, WHK SIP director.

  2. Silicon carbide reinforced silicon carbide composite

    Science.gov (United States)

    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.

  3. Pair distribution functions of silicon/silicon nitride interfaces

    Science.gov (United States)

    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.

  4. Silicon-on-ceramic process: silicon sheet growth and device development for the Large-Area Silicon Sheet and Cell Development Tasks of the Low-Cost Solar Array Project. Quarterly report No. 11, January 1-March 30, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, P.W.; Zook, J.D.; Heaps, J.D.; Grung, B.L.; Koepke, B.; Schuldt, S.B.

    1979-04-30

    The purpose of the research program is to investigate the technical and economic feasibility of producing solar-cell-quality sheet silicon by coating inexpensive ceramic substrates with a thin layer of polycrystalline silicon. The coating methods to be developed are directed toward a minimum-cost process for producing solar cells with a terrestrial conversion efficiency of 12 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 dip-coating method for putting silicon on ceramic (SOC) has been shown to produce solar-cell-quality sheet silicon. This method and a continuous coating process also being investigated have excellent scale-up potential which offers an outstanding, cost-effective way to manufacture large-area solar cells. Results and accomplishments are described.

  5. Low Hydrogen Content Silicon Nitride Films Deposited at Room Temperature with an ECR Plasma Source

    NARCIS (Netherlands)

    Isai, Gratiela I.; Holleman, Jisk; Wallinga, Hans; Woerlee, Pierre H.

    2004-01-01

    Silicon nitride layers with very low hydrogen content (less than 1 atomic percent) were deposited at near room temperature, from N2 and SiH4, with a multipolar electron cyclotron resonance plasma. The influences of pressure and nitrogen flow rate on physical and electrical properties were studied in

  6. Advances in silicon nanophotonics

    DEFF Research Database (Denmark)

    Hvam, Jørn Märcher; Pu, Minhao

    has been an obstacle for a simple realization of electro-optic modulators, and its indirect band gap has prevented the realization of efficient silicon light emitting diodes and lasers. Still, significant progress has been made in the past few years. Electro-optic modulators based on the free carrier...

  7. ALICE Silicon Strip Detector

    CERN Multimedia

    Nooren, G

    2013-01-01

    The Silicon Strip Detector (SSD) constitutes the two outermost layers of the Inner Tracking System (ITS) of the ALICE Experiment. The SSD plays a crucial role in the tracking of the particles produced in the collisions connecting the tracks from the external detectors (Time Projection Chamber) to the ITS. The SSD also contributes to the particle identification through the measurement of their energy loss.

  8. On nanostructured silicon success

    DEFF Research Database (Denmark)

    Sigmund, Ole; Jensen, Jakob Søndergaard; Frandsen, Lars Hagedorn

    2016-01-01

    Recent Letters by Piggott et al. 1 and Shen et al. 2 claim the smallest ever dielectric wave length and polarization splitters. The associated News & Views article by Aydin3 states that these works “are the first experimental demonstration of on-chip, silicon photonic components based on complex...

  9. Silicon Valley's Turnaround

    Institute of Scientific and Technical Information of China (English)

    Joseph Leu

    2006-01-01

    @@ During Silicon Valley's dramatic economic growth fueled by the Internet boom and business investment in information technology, employment in the region's high-tech sec tor tripled between 1995 and 2000. The economic boom gave rise to many new firms,drawing em ployees into high-tech jobs from other regions and other industries.

  10. Characterization of Silicon Carbide.

    Science.gov (United States)

    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.

  11. Composition Comprising Silicon Carbide

    Science.gov (United States)

    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.

  12. ALICE Silicon Pixel Detector

    CERN Multimedia

    Manzari, V

    2013-01-01

    The Silicon Pixel Detector (SPD) forms the innermost two layers of the 6-layer barrel Inner Tracking System (ITS). The SPD plays a key role in the determination of the position of the primary collision and in the reconstruction of the secondary vertices from particle decays.

  13. OPAL Silicon Tungsten Luminometer

    CERN Multimedia

    OPAL was one of the four experiments installed at the LEP particle accelerator from 1989 - 2000. The Silicon Tungsten Luminometer was part of OPAL's calorimeter which was used to measure the energy of particles. Most particles end their journey in calorimeters. These detectors measure the energy deposited when particles are slowed down and stopped.

  14. High-Q silicon carbide photonic-crystal cavities

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jonathan Y. [Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York 14627 (United States); Lu, Xiyuan [Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (United States); Lin, Qiang, E-mail: qiang.lin@rochester.edu [Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York 14627 (United States); Institute of Optics, University of Rochester, Rochester, New York 14627 (United States)

    2015-01-26

    We demonstrate one-dimensional photonic-crystal nanobeam cavities in amorphous silicon carbide. The fundamental mode exhibits intrinsic optical quality factor as high as 7.69 × 10{sup 4} with mode volume ∼0.60(λ/n){sup 3} at wavelength 1.5 μm. A corresponding Purcell factor value of ∼10{sup 4} is the highest reported to date in silicon carbide optical cavities. The device exhibits great potential for integrated nonlinear photonics and cavity nano-optomechanics.

  15. Nanocrystalline silicon prepared at high growth rate using helium dilution

    Indian Academy of Sciences (India)

    Koyel Bhattacharya; Debajyoti Das

    2008-06-01

    Growth and optimization of the nanocrystalline silicon (nc-Si : H) films have been studied by varying the electrical power applied to the helium diluted silane plasma in RF glow discharge. Wide optical gap and conducting intrinsic nanocrystalline silicon network of controlled crystalline volume fraction and oriented crystallographic lattice planes have been obtained at a reasonably high growth rate from helium diluted silane plasma, without using hydrogen. Improving crystallinity in the network comprising ∼ 10 nm Si-nanocrystallites and contributing optical gap widening, conductivity ascending and that obtained during simultaneous escalation of the deposition rate, promises significant technological impact.

  16. Silicon in beer and brewing.

    Science.gov (United States)

    Casey, Troy R; Bamforth, Charles W

    2010-04-15

    It has been claimed that beer is one of the richest sources of silicon in the diet; however, little is known of the relationship between silicon content and beer style and the manner in which beer is produced. The purpose of this study was to measure silicon in a diversity of beers and ascertain the grist selection and brewing factors that impact the level of silicon obtained in beer. Commercial beers ranged from 6.4 to 56.5 mg L(-1) in silicon. Products derived from a grist of barley tended to contain more silicon than did those from a wheat-based grist, likely because of the high levels of silica in the retained husk layer of barley. Hops contain substantially more silicon than does grain, but quantitatively hops make a much smaller contribution than malt to the production of beer and therefore relatively less silicon in beer derives from them. During brewing the vast majority of the silicon remains with the spent grains; however, aggressive treatment during wort production in the brewhouse leads to increased extraction of silicon into wort and much of this survives into beer. It is confirmed that beer is a very rich source of silicon. (c) 2010 Society of Chemical Industry.

  17. Deep Reactive Ion Etched Anti-Reflection Coatings for Sub-millimeter Silicon Optics

    CERN Document Server

    Gallardo, Patricio A; Cothard, Nicholas; Bruno, Sarah Marie M; Cortes-Medellin, German; Marchetti, Galen; Miller, Kevin H; Mockler, Brenna; Niemack, Michael D; Stacey, Gordon; Wollack, Edward J

    2016-01-01

    Refractive optical elements are widely used in millimeter and sub-millimeter astronomical telescopes. High resistivity silicon is an excellent material for dielectric lenses given its low loss-tangent, high thermal conductivity and high index of refraction. The high index of refraction of silicon causes a large Fresnel reflectance at the vacuum-silicon interface (up to 30%), which can be reduced with an anti-reflection (AR) coating. In this work we report techniques for efficiently AR coating silicon at sub-millimeter wavelengths using Deep Reactive Ion Etching (DRIE) and bonding the coated silicon to another silicon optic. Silicon wafers of 100 mm diameter (1 mm thick) were coated and bonded using the Silicon Direct Bonding technique at high temperature (1100 C). No glue is used in this process. Optical tests using a Fourier Transform Spectrometer (FTS) show sub-percent reflections for a single-layer DRIE AR coating designed for use at 320 microns on a single wafer. Cryogenic (10 K) measurements of a bonded ...

  18. A useful method to overcome the difficulties of applying silicone gel sheet on irregular surfaces.

    Science.gov (United States)

    Grella, Roberto; Nicoletti, Gianfranco; D'Ari, Antonio; Romanucci, Vincenza; Santoro, Mariangela; D'Andrea, Francesco

    2015-04-01

    To date, silicone gel and silicone occlusive plates are the most useful and effective treatment options for hypertrophic scars (surgical and traumatic). Use of silicone sheeting has also been demonstrated to be effective in the treatment of minor keloids in association with corticosteroid intralesional infiltration. In our practice, we encountered four problems: maceration, rashes, pruritus and infection. Not all patients are able to tolerate the cushion, especially children, and certain anatomical regions as the face and the upper chest are not easy to dress for obvious social, psychological and aesthetic reasons. In other anatomical regions, it is also difficult to obtain adequate compression and occlusion of the scar. To overcome such problems of applying silicone gel sheeting, we tested the use of liquid silicone gel (LSG) in the treatment of 18 linear hypertrophic scars (HS group) and 12 minor keloids (KS group) as an alternative to silicone gel sheeting or cushion. Objective parameters (volume, thickness and colour) and subjective symptoms such as pain and pruritus were examined. Evaluations were made when the therapy started and after 30, 90 and 180 days of follow-up. After 90 days of treatment with silicone gel alone (two applications daily), HS group showed a significant improvement in terms of volume decrease, reduced inflammation and redness and improved elasticity. In conclusion, on the basis of our clinical data, we find LSG to be a useful method to overcome the difficulties of applying silicone gel sheeting on irregular surface.

  19. Microleakage of composite resin restorations with a 10 percent maleic acid etchant.

    Science.gov (United States)

    Gilpatrick, R O; Owens, B M; Kaplan, I; Cook, G

    1996-04-01

    Microleakage of Class V composite resin restorations with margins all in enamel were compared in this in-vitro study using Scotchbond MultiPurpose Adhesive (SMP) (3M Corp.), and Scotchbond II (SB II) (3M Corp). Twenty extracted human molars were randomly separated into two groups: Group One, which used the SMP system and Group Two, which used the SB II system. Circular Class V preparations were cut 1.8 mm deep and 3 mm in diameter using a #556 fissure bur. Cavosurface margins, all in enamel, were beveled. The enamel and dentin were treated following manufacturer's directions for each group, and a microfilled composite resin, Silux Plus (3M Corp), was applied in two hand-placed increments. All teeth were finished with Sof-Lex discs, stored in water for seven days, then thermocycled in a water bath for 100 cycles, alternating from 4 degrees C to 58 degrees C. The teeth were placed in a 5 percent solution of methylene blue, rinsed and then invested in resin. All teeth were sectioned vertically and horizontally and a ratio (percentage) of wall length to amount of leakage along each wall was established. The overall mean leakage of Group One was 15.27 percent and Group Two was 13.84 percent. Looking at individual walls, the mean occlusal wall leakage of Group One was 28.41 percent and Group Two was 12.45 percent. Mean gingival wall leakage of Group One was 15.96 percent and Group Two was 21.80 percent. Comparing the two groups, using a student's t test, there was no significant difference between the overall mean leakage or between the gingival wall leakage (p > 0.05); however, there was a significant difference between the occlusal wall leakage (p < 0.05), with SMP exhibiting more leakage.

  20. Thermal residual stresses in silicon-carbide/titanium (0/90) laminate

    Science.gov (United States)

    Bigelow, C. A.

    1992-01-01

    The current work formulated a micromechanical analysis of a cross-ply laminate and calculated the thermal residual stress in a very thick (0/90)(sub 2n) silicon-carbide/titanium laminate. Results were also shown for a unidirectional laminate of the same material. Discrete fiber-matrix models assuming a rectangular array of fibers with a fiber volume fraction of 32.5 percent and a three-dimensional, finite-element analysis were used. Significant differences in the trends and magnitudes for the fiber, matrix, and interface stresses were calculated for unidirectional and (0/90) models. Larger hoop stresses calculated for the (0/90) model indicate that it may be more susceptible to radial cracking when subjected to mechanical loading than the unidirectional model. The axial stresses in the matrix were calculated to be slightly larger for the (0/90) model. The compressive axial stresses in the fiber were significantly larger in the (0/90) model. The presence of the cross-ply in the (0/90) model reduced the constraint on the fiber, producing radial interface stresses that were less compressive, which could lead to earlier failure of the fiber-matrix interface.

  1. Body mass index and percent body fat: a meta analysis among different ethnic groups.

    Science.gov (United States)

    Deurenberg, P; Yap, M; van Staveren, W A

    1998-12-01

    To study the relationship between percent body fat and body mass index (BMI) in different ethnic groups and to evaluate the validity of the BMI cut-off points for obesity. Meta analysis of literature data. Populations of American Blacks, Caucasians, Chinese, Ethiopians, Indonesians, Polynesians and Thais. Mean values of BMI, percent body fat, gender and age were adapted from original papers. The relationship between percent body fat and BMI differs in the ethnic groups studied. For the same level of body fat, age and gender, American Blacks have a 1.3 kg/m2 and Polynesians a 4.5 kg/m2 lower BMI compared to Caucasians. By contrast, in Chinese, Ethiopians, Indonesians and Thais BMIs are 1.9, 4.6, 3.2 and 2.9 kg/m2 lower compared to Caucasians, respectively. Slight differences in the relationship between percent body fat and BMI of American Caucasians and European Caucasians were also found. The differences found in the body fat/BMI relationship in different ethnic groups could be due to differences in energy balance as well as to differences in body build. The results show that the relationship between percent body fat and BMI is different among different ethnic groups. This should have public health implications for the definitions of BMI cut-off points for obesity, which would need to be population-specific.

  2. Stress induced phase transitions in silicon

    Science.gov (United States)

    Budnitzki, M.; Kuna, M.

    2016-10-01

    Silicon has a tremendous importance as an electronic, structural and optical material. Modeling the interaction of a silicon surface with a pointed asperity at room temperature is a major step towards the understanding of various phenomena related to brittle as well as ductile regime machining of this semiconductor. If subjected to pressure or contact loading, silicon undergoes a series of stress-driven phase transitions accompanied by large volume changes. In order to understand the material's response for complex non-hydrostatic loading situations, dedicated constitutive models are required. While a significant body of literature exists for the dislocation dominated high-temperature deformation regime, the constitutive laws used for the technologically relevant rapid low-temperature loading have severe limitations, as they do not account for the relevant phase transitions. We developed a novel finite deformation constitutive model set within the framework of thermodynamics with internal variables that captures the stress induced semiconductor-to-metal (cd-Si → β-Si), metal-to-amorphous (β-Si → a-Si) as well as amorphous-to-amorphous (a-Si → hda-Si, hda-Si → a-Si) transitions. The model parameters were identified in part directly from diamond anvil cell data and in part from instrumented indentation by the solution of an inverse problem. The constitutive model was verified by successfully predicting the transformation stress under uniaxial compression and load-displacement curves for different indenters for single loading-unloading cycles as well as repeated indentation. To the authors' knowledge this is the first constitutive model that is able to adequately describe cyclic indentation in silicon.

  3. DNA hybridization on silicon nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Shalini, E-mail: shalinsin@gmail.co [Electronic Materials Division, National Physical Laboratory (CSIR), Dr. K. S. Krishnan Marg, New Delhi-110012 (India); Faculty of Life Science, Aligarh Muslim University, Aligarh-202001 (India); Zack, Jyoti [Dr. B.R Ambedkar Center for Biomedical Research, University of Delhi, Delhi-110007 (India); Kumar, Dinesh; Srivastava, S.K.; Govind [Electronic Materials Division, National Physical Laboratory (CSIR), Dr. K. S. Krishnan Marg, New Delhi-110012 (India); Saluja, Daman [Dr. B.R Ambedkar Center for Biomedical Research, University of Delhi, Delhi-110007 (India); Khan, M.A. [Faculty of Life Science, Aligarh Muslim University, Aligarh-202001 (India); Singh, P.K. [Electronic Materials Division, National Physical Laboratory (CSIR), Dr. K. S. Krishnan Marg, New Delhi-110012 (India)

    2010-11-30

    Nanowire-based detection strategies provide promising new routes to bioanalysis and indeed are attractive to conventional systems because of their small size, high surface-to-volume ratios, electronic, and optical properties. A sequence-specific detection of single-stranded oligonucleotides using silicon nanowires (SiNWs) is demonstrated. The surface of the SiNWs is functionalized with densely packed organic monolayer via hydrosilylation for covalent attachment. Subsequently, deoxyribonucleic acid (DNA) is immobilized to recognize the complementary target DNA. The biomolecular recognition properties of the nanowires are tested via hybridization with {sup {gamma}P32} tagged complementary and non-complementary DNA oligonucleotides, showing good selectivity and reversibility. No significant non-specific binding to the incorrect sequences is observed. X-ray photoelectron spectroscopy, fluorescence imaging, and nanodrop techniques are used to characterize the modified SiNWs and covalent attachment with DNA. The results show that SiNWs are excellent substrates for the absorption, stabilization and detection of DNA sequences and could be used for DNA microarrays and micro fabricated SiNWs DNA sensors.

  4. High aspect ratio transmission line circuits micromachined in silicon

    Science.gov (United States)

    Todd, Shane Truman

    The performance of complimentary metal-oxide-semiconductor (CMOS) monolithic microwave integrated circuits (MMICs) fabricated on silicon has improved dramatically. The scaling down of silicon transistors has increased the maximum frequency of transistors to the point where silicon MMICs have become a viable alternative to compound semiconductor MMICs in certain applications. A fundamental problem still exists in silicon MMICs however in that transmission lines fabricated on silicon can suffer from high loss due to the finite conductivity of the silicon substrate. A novel approach for creating low-loss transmission lines on silicon is presented in this work. Low-loss transmission lines are created on low resistivity silicon by using a micromachining method that combines silicon deep reactive ion etching (DRIE), thermal oxidation, electroplating, and planarization. Two types of high aspect ratio transmission lines are created with this method including high aspect ratio coplanar waveguide (hicoplanar) and semi-rectangular coaxial (semicoaxial). Transmission lines with impedances ranging from 20--80 O have been fabricated with minimum measured loss lower than 1 dB/cm at 67 GHz. Low-loss dielectrics are created for the high aspect ratio transmission lines using the mesa merging method. The mesa merging method works by creating silicon mesa arrays using DRIE and then converting and merging the mesa arrays into a solid oxide dielectric using thermal oxidation. The transmission lines are designed so that the fields penetrate the low-loss oxide dielectric and are isolated from the lossy silicon substrate. The mesa merging method has successfully created large volume oxide with depth up to 65 microm and width up to 240 microm in short oxidation times. Other advantages of the high aspect ratio transmission lines are demonstrated including low-loss over a wide impedance range, high isolation, and high coupling for coupled-line circuits. Transmission line models have been

  5. Crystalline-silicon photovoltaics: Necessary and sufficient

    Science.gov (United States)

    Basore, P. A.; Gee, J. M.

    Photovoltaic (PV) energy systems have always been dominated by crystalline-silicon (c-Si) technology, and recent developments persuasively suggest that c-Si will continue to be the dominant technology well into the next century. The authors explain why c-Si technology is fairing much better than previously expected, and discuss the impact of improvements currently under development. They use a ground-up, engineering-based approach to predict the expected evolution of this type of PV system, and argue that c-Si PV will be in a position to compete for the US residential power market starting in about the year 2010. This market alone will provide the opportunity for PV to supply several percent of the electrical energy used in the United States. Crystalline-silicon technology is therefore not just necessary for building a near-term PV industry; it also offers a low-risk approach to meeting long-term goals for PV energy systems.

  6. High temperature deformation of silicon steel

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Calvillo, Pablo, E-mail: pablo.rodriguez@ctm.com.es [CTM - Technologic Centre, Materials Technology Area, Manresa, Cataluna (Spain); Department of Materials Science and Metallurgical Engineering, Universidad Politecnica de Cataluna, Barcelona (Spain); Houbaert, Yvan, E-mail: Yvan.Houbaert@UGent.be [Department of Materials Science and Engineering, University of Ghent (Belgium); Petrov, Roumen, E-mail: Roumen.Petrov@ugent.be [Department of Materials Science and Engineering, University of Ghent (Belgium); Kestens, Leo, E-mail: Leo.kestens@ugent.be [Department of Materials Science and Engineering, University of Ghent (Belgium); Colas, Rafael, E-mail: rafael.colas@uanl.edu.mx [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon (Mexico); Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia, Universidad Autonoma de Nuevo Leon (Mexico)

    2012-10-15

    The microstructure and texture development during high temperature plane strain compression of 2% in weight silicon steel was studied. The tests were carried out at a constant strain rate of 5 s{sup -1} with reductions of 25, 35 and 75% at temperatures varying from 800 to 1100 Degree-Sign C. The changes in microstructure and texture were studied by means of scanning electron microscopy and electron backscattered diffraction. The microstructure close to the surface of the samples was equiaxed, which is attributed to the shear caused by friction, whereas that at the centre of the specimens was made of a mixture of elongated and fine equiaxed grains, the last ones attributed to the action of dynamic recovery followed by recrystallization. It was found that the volume fraction of these equiaxed grains augmented as reduction and temperature increased; a 0.7 volume fraction was accomplished with a 75% reduction at 1100 Degree-Sign C. The texture of the equiaxed and elongated grains was found to vary with the increase of deformation and temperature, as the {gamma}-fibre tends to disappear and the {alpha}-fibre to increase towards the higher temperature range. -- Highlights: Black-Right-Pointing-Pointer The plastic deformation of a silicon containing steel is studied by plane strain compression. Black-Right-Pointing-Pointer Equiaxed and elongated grains develop in different regions of the sample due to recrystallization. Black-Right-Pointing-Pointer Texture, by EBSD, is revealed to be similar in either type of grains.

  7. The Belle II Silicon Vertex Detector

    Energy Technology Data Exchange (ETDEWEB)

    Friedl, M., E-mail: markus.friedl@oeaw.ac.at [HEPHY – Institute of High Energy Physics, Nikolsdorfer Gasse 18, 1050 Vienna (Austria); Ackermann, K. [MPI Munich, Föhringer Ring 6, 80805 München (Germany); Aihara, H. [University of Tokyo, Department of Physics, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Aziz, T. [Tata Institute of Fundamental Research, Experimental High Energy Physics Group, Homi Bhabha Road, Mumbai 400 005 (India); Bergauer, T. [HEPHY – Institute of High Energy Physics, Nikolsdorfer Gasse 18, 1050 Vienna (Austria); Bozek, A. [Institute of Nuclear Physics, Division of Particle Physics and Astrophysics, ul. Radzikowskiego 152, 31 342 Krakow (Poland); Campbell, A. [DESY, Notkestrasse 85, 22607 Hamburg (Germany); Dingfelder, J. [University of Bonn, Department of Physics and Astronomy, Nussallee 12, 53115 Bonn (Germany); Drasal, Z. [Charles University, Institute of Particle and Nuclear Physics, Ke Karlovu 3, 121 16 Praha 2 (Czech Republic); Frankenberger, A. [HEPHY – Institute of High Energy Physics, Nikolsdorfer Gasse 18, 1050 Vienna (Austria); Gadow, K. [DESY, Notkestrasse 85, 22607 Hamburg (Germany); Gfall, I. [HEPHY – Institute of High Energy Physics, Nikolsdorfer Gasse 18, 1050 Vienna (Austria); Haba, J.; Hara, K.; Hara, T. [KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Higuchi, T. [University of Tokyo, Kavli Institute for Physics and Mathematics of the Universe, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Himori, S. [Tohoku University, Department of Physics, Aoba Aramaki Aoba-ku, Sendai 980-8578 (Japan); Irmler, C. [HEPHY – Institute of High Energy Physics, Nikolsdorfer Gasse 18, 1050 Vienna (Austria); Ishikawa, A. [Tohoku University, Department of Physics, Aoba Aramaki Aoba-ku, Sendai 980-8578 (Japan); Joo, C. [Seoul National University, High Energy Physics Laboratory, 25-107 Shinlim-dong, Kwanak-gu, Seoul 151-742 (Korea, Republic of); and others

    2013-12-21

    The KEKB machine and the Belle experiment in Tsukuba (Japan) are now undergoing an upgrade, leading to an ultimate luminosity of 8×10{sup 35}cm{sup −2}s{sup −1} in order to measure rare decays in the B system with high statistics. The previous vertex detector cannot cope with this 40-fold increase of luminosity and thus needs to be replaced. Belle II will be equipped with a two-layer Pixel Detector surrounding the beam pipe, and four layers of double-sided silicon strip sensors at higher radii than the old detector. The Silicon Vertex Detector (SVD) will have a total sensitive area of 1.13m{sup 2} and 223,744 channels—twice as many as its predecessor. All silicon sensors will be made from 150 mm wafers in order to maximize their size and thus to reduce the relative contribution of the support structure. The forward part has slanted sensors of trapezoidal shape to improve the measurement precision and to minimize the amount of material as seen by particles from the vertex. Fast-shaping front-end amplifiers will be used in conjunction with an online hit time reconstruction algorithm in order to reduce the occupancy to the level of a few percent at most. A novel “Origami” chip-on-sensor scheme is used to minimize both the distance between strips and amplifier (thus reducing the electronic noise) as well as the overall material budget. This report gives an overview on the status of the Belle II SVD and its components, including sensors, front-end detector ladders, mechanics, cooling and the readout electronics.

  8. Incoherent-light processing of single- and poly-crystalline silicon solar cells

    Science.gov (United States)

    Nielsen, L. D.; Larsen, A. N.

    Transient heating with incoherent continuous light from a xenon arc-lamp has been studied as a possible process step in the production of single- and poly-crystalline silicon solar cells. Annealing of phosphorus and arsenic ion implantations have been made, with phosphorus implantations leading to solar cell efficiences of 8.3 and 5.8 percent for 100 single crystal and Wacker-SILSO materials, respectively, both without AR-coating. Furthermore, incoherent-light induced diffusion of phosphorus from spin-on deposited doped oxide layer has been studied and has resulted in efficiencies of 7.9 and 6.6 percent, respectively, for the same two types of material. This latter process is concluded to be a promising technique for production of low-cost silicon solar cells with efficiencies of at least 10 percent without any vacuum or high-temperature furnace process steps.

  9. Nanostructured silicon carbon thin films grown by plasma enhanced chemical vapour deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Coscia, U. [Dipartimento di Fisica, Università di Napoli “Federico II” Complesso Universitario MSA, via Cinthia, 80126 Napoli (Italy); CNISM Unita' di Napoli, Complesso Universitario MSA, via Cinthia, 80126 Napoli (Italy); Ambrosone, G., E-mail: ambrosone@na.infn.it [Dipartimento di Fisica, Università di Napoli “Federico II” Complesso Universitario MSA, via Cinthia, 80126 Napoli (Italy); SPIN-CNR, Complesso Universitario MSA, via Cinthia, 80126 Napoli (Italy); Basa, D.K. [Department of Physics, Utkal University, Bhubaneswar 751004 (India); Rigato, V. [INFN Laboratori Nazionali Legnaro, 35020 Legnaro (Padova) (Italy); Ferrero, S.; Virga, A. [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino (Italy)

    2013-09-30

    Nanostructured silicon carbon thin films, composed of Si nanocrystallites embedded in hydrogenated amorphous silicon carbon matrix, have been prepared by varying rf power in ultra high vacuum plasma enhanced chemical vapour deposition system using silane and methane gas mixtures diluted in hydrogen. In this paper we have studied the compositional, structural and electrical properties of these films as a function of rf power. It is shown that with increasing rf power the atomic densities of carbon and hydrogen increase while the atomic density of silicon decreases, resulting in a reduction in the mass density. Further, it is demonstrated that carbon is incorporated into amorphous matrix and it is mainly bonded to silicon. The study has also revealed that the crystalline volume fraction decreases with increase in rf power and that the films deposited with low rf power have a size distribution of large and small crystallites while the films deposited with relatively high power have only small crystallites. Finally, the enhanced transport properties of the nanostructured silicon carbon films, as compared to amorphous counterpart, have been attributed to the presence of Si nanocrystallites. - Highlights: • The mass density of silicon carbon films decreases from 2.3 to 2 g/cm{sup 3}. • Carbon is incorporated in the amorphous phase and it is mainly bonded to silicon. • Nanostructured silicon carbon films are deposited at rf power > 40 W. • Si nanocrystallites in amorphous silicon carbon enhance the electrical properties.

  10. The Synthesis and Structural Properties of Crystalline Silicon Quantum Dots upon Thermal Annealing of Hydrogenated Amorphous Si-Rich Silicon Carbide Films

    Science.gov (United States)

    Wen, Guozhi; Zeng, Xiangbin; Li, Xianghu

    2016-08-01

    Silicon quantum dots (QDs) embedded in non-stoichiometric hydrogenated silicon carbide (SiC:H) thin films have been successfully synthesized by plasma-enhanced chemical vapor deposition and post-annealing. The chemical composition analyses have been carried out by x-ray photoelectron spectroscopy (XPS). The bonding configurations have been deduced from Fourier transform infrared absorption measurements (FTIR). The evolution of microstructure with temperature has been characterized by glancing incident x-ray diffraction (XRD) and Raman diffraction spectroscopy. XPS and FTIR show that it is in Si-rich feature and there are a few hydrogenated silicon clusters in the as-grown sample. XRD and Raman diffraction spectroscopy show that it is in amorphous for the as-grown sample, while crystalline silicon QDs have been synthesized in the 900°C annealed sample. Silicon atoms precipitation from the SiC matrix or silicon phase transition from amorphous SiC is enhanced with annealing temperature increase. The average sizes of silicon QDs are about 5.1 nm and 5.6 nm, the number densities are as high as 1.7 × 1012 cm-2 and 3.2 × 1012 cm-2, and the crystalline volume fractions are about 58.3% and 61.3% for the 900°C and 1050°C annealed samples, respectively. These structural properties analyses provide an understanding about the synthesis of silicon QDs upon thermal annealing for applications in next generation optoelectronic and photovoltaic devices.

  11. Stereochemistry of silicon in oxygen-containing compounds

    Science.gov (United States)

    Serezhkin, V. N.; Urusov, V. S.

    2017-01-01

    Specific stereochemical features of silicon in oxygen-containing compounds, including hybrid silicates with all oxygen atoms of SiOn groups (n = 4, 5, or 6) entering into the composition of organic anions or molecules, are described by characteristics of Voronoi—Dirichlet polyhedra. It is found that in rutile-like stishovite and post-stishovite phases with the structures similar to those of CaCl2, α-PbO2, or pyrite FeS2, the volume of Voronoi—Dirichlet polyhedra of silicon and oxygen atoms decreases linearly with pressure increasing to 268 GPa. Based on these results, the possibility of formation of new post-stishovite phases is shown, namely, the fluorite-like structure (transition predicted at 400 GPa) and a body-centered cubic lattice with statistical arrangement of silicon and oxygen atoms ( 900 GPa).

  12. Plasma deposition of amorphous silicon-based materials

    CERN Document Server

    Bruno, Giovanni; Madan, Arun

    1995-01-01

    Semiconductors made from amorphous silicon have recently become important for their commercial applications in optical and electronic devices including FAX machines, solar cells, and liquid crystal displays. Plasma Deposition of Amorphous Silicon-Based Materials is a timely, comprehensive reference book written by leading authorities in the field. This volume links the fundamental growth kinetics involving complex plasma chemistry with the resulting semiconductor film properties and the subsequent effect on the performance of the electronic devices produced. Key Features * Focuses on the plasma chemistry of amorphous silicon-based materials * Links fundamental growth kinetics with the resulting semiconductor film properties and performance of electronic devices produced * Features an international group of contributors * Provides the first comprehensive coverage of the subject, from deposition technology to materials characterization to applications and implementation in state-of-the-art devices.

  13. Photonic hyperuniform networks by silicon double inversion of polymer templates

    CERN Document Server

    Muller, Nicolas; Marichy, Catherine; Scheffold, Frank

    2016-01-01

    Hyperuniform disordered networks belong to a peculiar class of structured materials predicted to possess partial and complete photonic bandgaps for relatively moderate refractive index contrasts. The practical realization of such photonic designer materials is challenging however, as it requires control over a multi-step fabcrication process on optical length scales. Here we report the direct-laser writing of hyperuniform polymeric templates followed by a silicon double inversion procedure leading to high quality network structures made of polycrystalline silicon. We observe a pronounced gap in the shortwave infrared centered at a wavelength of $\\lambda_{\\text{Gap}}\\simeq $ 2.5 $\\mu$m, in nearly quantitative agreement with numerical simulations. In the experiments the typical structural length scale of the seed pattern can be varied between 2 $\\mu$m and 1.54 $\\mu$m leading to a blue-shift of the gap accompanied by an increase of the silicon volume filling fraction.

  14. MMP-2 detective silicon nanowire biosensor using enzymatic cleavage reaction.

    Science.gov (United States)

    Choi, Jin-Ha; Kim, Han; Kim, Hyun-Soo; Um, Soong Ho; Choi, Jeong-Woo; Oh, Byung-Keun

    2013-04-01

    Matrix metalloproteinases are proteolytic enzymes that play a significant role in tissue remodeling related with various pathological and physiological processes such as tissue repair, angiogenesis, cirrhosis, morphogenesis, arthritis, and metastasis. Especially, MMP-2 has been shown to be related with benign prostatic hyperplasia and prostate cancer. Therefore, there is a need to make sensors with high sensitivity that can measure MMP-2 concentrations precisely. Silicon nanowires have been used in the development of high sensitive chemical sensors and biosensors. The high sensitivity of silicon nanowire based sensor originates in its high surface to volume ratio and ability to field-effect induced local charge transfers. In this study, 100 nm silicon nanowire based field-effect transistors (FET) device was fabricated by electron-beam lithography and MMP-2 was successfully measured by conductance versus time characteristics within 1 pM to 100 nM.

  15. WHY WE NEED 100 PERCENT RENEWABLE ENERGIES: A PLEA FOR THE ENERGIEWENDE

    Directory of Open Access Journals (Sweden)

    Christian Hinsch

    2014-05-01

    Full Text Available Those familiar with the fifth intergovernmental Penal on Climate Change report presented in late 2013 can no longer seriously doubt that climate change has become a reality. Although the issue has been the subject of several high profile international conferences, little has been achieved so far. Fossil power plants still continue to emit massive amounts of greenhouse gases further accelerating climate change. There is, however, an alternative to our current climate-damaging way of energy production: The complete transition towards 100 percent renewable energies. This paper examines the way in which an industrialized country like Germany can become a 100 percent renewable by 2020.

  16. Investigation on Silicon Thin Film Solar Cells

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The preparation, current status and trends are investigated for silicon thin film solar cells. The advantages and disadvantages of amorphous silicon thin film, polycrystalline silicon thin film and mono-crystalline silicon thin film solar cells are compared. The future development trends are pointed out. It is found that polycrystalline silicon thin film solar cells will be more promising for application with great potential.

  17. A silicon electromechanical photodetector

    CERN Document Server

    Tallur, Siddharth

    2013-01-01

    Opto-mechanical systems have enabled wide-band optical frequency conversion and multi-channel 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 micro-resonator, which converts near-IR optical intensity modulation at 174.2MHz and 1.198GHz 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.

  18. The CMS silicon tracker

    Energy Technology Data Exchange (ETDEWEB)

    Focardi, E. E-mail: focardi@pi.infn.it; Albergo, S.; Angarano, M.; Azzi, P.; Babucci, E.; Bacchetta, N.; Bader, A.; Bagliesi, G.; Basti, A.; Biggeri, U.; Bilei, G.M.; Bisello, D.; Boemi, D.; Bosi, F.; Borrello, L.; Bozzi, C.; Braibant, S.; Breuker, H.; Bruzzi, M.; Buffini, A.; Busoni, S.; Candelori, A.; Caner, A.; Castaldi, R.; Castro, A.; Catacchini, E.; Checcucci, B; Ciampolini, P.; Civinini, C.; Creanza, D.; D' Alessandro, R.; Da Rold, M.; Demaria, N.; De Palma, M.; Dell' Orso, R.; Della Marina, R.; Dutta, S.; Eklund, C.; Feld, L.; Fiore, L.; French, M.; Freudenreich, K.; Frey, A.; Fuertjes, A.; Giassi, A.; Giorgi, M.; Giraldo, A.; Glessing, B.; Gu, W.H.; Hall, G.; Hammarstrom, R.; Hebbeker, T.; Honma, A.; Hrubec, J.; Huhtinen, M.; Kaminsky, A.; Karimaki, V.; Koenig, St.; Krammer, M.; Lariccia, P.; Lenzi, M.; Loreti, M.; Leubelsmeyer, K.; Lustermann, W.; Maettig, P.; Maggi, G.; Mannelli, M.; Mantovani, G.; Marchioro, A.; Mariotti, C.; Martignon, G.; Evoy, B.Mc; Meschini, M.; Messineo, A.; Migliore, E.; My, S.; Paccagnella, A.; Palla, F.; Pandoulas, D.; Papi, A.; Parrini, G.; Passeri, D.; Pieri, M.; Piperov, S.; Potenza, R.; Radicci, V.; Raffaelli, F.; Raymond, M.; Rizzo, F.; Santocchia, A.; Schmitt, B.; Selvaggi, G.; Servoli, L.; Sguazzoni, G.; Siedling, R.; Silvestris, L.; Starodumov, A.; Stavitski, I.; Stefanini, G.; Surrow, B.; Tempesta, P.; Tonelli, G.; Tricomi, A.; Tuuva, T.; Vannini, C.; Verdini, P.G.; Viertel, G.; Xie, Z.; Yahong, Li; Watts, S.; Wittmer, B

    2000-10-11

    This paper describes the Silicon microstrip Tracker of the CMS experiment at LHC. It consists of a barrel part with 5 layers and two endcaps with 10 disks each. About 10 000 single-sided equivalent modules have to be built, each one carrying two daisy-chained silicon detectors and their front-end electronics. Back-to-back modules are used to read-out the radial coordinate. The tracker will be operated in an environment kept at a temperature of T=-10 deg. C to minimize the Si sensors radiation damage. Heavily irradiated detectors will be safely operated due to the high-voltage capability of the sensors. Full-size mechanical prototypes have been built to check the system aspects before starting the construction.

  19. Superhydrophobic Porous Silicon Surfaces

    Directory of Open Access Journals (Sweden)

    Paolo NENZI

    2011-12-01

    Full Text Available In this paper, we present an inexpensive technique to produce superhydrophobic surfaces from porous silicon. Superhydrophobic surfaces are a key technology for their ability to reduce friction losses in microchannels and their self cleaning properties. The morphology of a p-type silicon wafer is modified by a electrochemical wet etch to produce pores with controlled size and distribution and coated with a silane hydrophobic layer. Surface morphology is characterized by means of scanning electron microscope images. Large contact angles are observed on such surfaces and the results are compared with classical wetting models (Cassie and Wenzel suggesting a mixed Wenzel-Cassie behavior. The presented technique represents a cost-effective means for friction reduction in microfluidic applications, such as lab-on-a-chip.

  20. Haematic silicon in drowning.

    Science.gov (United States)

    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.

  1. Silicon nanowire transistors

    CERN Document Server

    Bindal, Ahmet

    2016-01-01

    This book describes the n and p-channel Silicon Nanowire Transistor (SNT) designs with single and dual-work functions, emphasizing low static and dynamic power consumption. The authors describe a process flow for fabrication and generate SPICE models for building various digital and analog circuits. These include an SRAM, a baseband spread spectrum transmitter, a neuron cell and a Field Programmable Gate Array (FPGA) platform in the digital domain, as well as high bandwidth single-stage and operational amplifiers, RF communication circuits in the analog domain, in order to show this technology’s true potential for the next generation VLSI. Describes Silicon Nanowire (SNW) Transistors, as vertically constructed MOS n and p-channel transistors, with low static and dynamic power consumption and small layout footprint; Targets System-on-Chip (SoC) design, supporting very high transistor count (ULSI), minimal power consumption requiring inexpensive substrates for packaging; Enables fabrication of different types...

  2. Building China's Silicon Valley

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Ellis Rahhal and Andrew Schorr sit across from each other in the minimalist office of their tech startup,all clean lines and white linoleum floors.A pair of toothbrushes hint at many a late night hunched over their computers.Outside the window,the sun is slowly setting behind jagged mountains.The scene is classic Silicon Valley.But Rahhal and Schorr aren't in California.They're in suburban Beijing.

  3. Silicon Containing Photoresists.

    Science.gov (United States)

    1987-11-13

    generation of high resolution patterns. The vast majority of the commercial positive photoresists are comprised of a base soluble Novolac type resin (Cresol...plays a passive role. The generation of silicon containing Novolac- type resins represents one such effort. Workers at AT&T Bell Labs have prepared a...and formaldehyde (20). The silylated Novolac type resins were designed for use with substituted 1,2-napthoquinone-2-diazide sensitizers employed in

  4. Bringing Silicon Valley inside.

    Science.gov (United States)

    Hamel, G

    1999-01-01

    In 1998, Silicon Valley companies produced 41 IPOs, which by January 1999 had a combined market capitalization of $27 billion--that works out to $54,000 in new wealth creation per worker in a single year. Multiply the number of employees in your company by $54,000. Did your business create that much new wealth last year? Half that amount? It's not a group of geniuses generating such riches. It's a business model. In Silicon Valley, ideas, capital, and talent circulate freely, gathering into whatever combinations are most likely to generate innovation and wealth. Unlike most traditional companies, which spend their energy in resource allocation--a system designed to avoid failure--the Valley operates through resource attraction--a system that nurtures innovation. In a traditional company, people with innovative ideas must go hat in hand to the guardians of the old ideas for funding and for staff. But in Silicon Valley, a slew of venture capitalists vie to attract the best new ideas, infusing relatively small amounts of capital into a portfolio of ventures. And talent is free to go to the companies offering the most exhilarating work and the greatest potential rewards. It should actually be easier for large, traditional companies to set up similar markets for capital, ideas, and talent internally. After all, big companies often already have extensive capital, marketing, and distribution resources, and a first crack at the talent in their own ranks. And some of them are doing it. The choice is yours--you can do your best to make sure you never put a dollar of capital at risk, or you can tap into the kind of wealth that's being created every day in Silicon Valley.

  5. Silicone oil implantation in penetrating injuries complicated by PVR. Results from 1982 to 1986.

    Science.gov (United States)

    Skorpik, C; Menapace, R; Gnad, H D; Paroussis, P

    1989-01-01

    Between 1982 and 1986, the authors implanted silicone oil in 34 eyes with retinal detachment and proliferative vitreoretinopathy (PVR) stages C-3 to D-3 caused by penetrating injuries. The retina had failed to reattach after initial vitrectomy, membrane peeling, and scleral buckling. Complete anatomic reattachment was achieved in 62%, partial reattachment in an additional 9%. Useful functional results were achieved in 68% of cases (visual acuity of 1/60 to 20/20). Postoperative complications included elevated intraocular pressure in 38% and progress of PVR with membrane formation under the silicone oil in 21% of the cases. Sixty-eight percent of the aphakic eyes developed band-shaped keratopathy. Because most of the eyes were aphakic, the authors do not report cataract incidence. In 15 eyes (44%) the silicone oil was removed. In 14 of these eyes the retina remains attached, in one eye silicone oil removal was followed by phthisis bulbi.

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

    Energy Technology Data Exchange (ETDEWEB)

    Buhmann, J.M. [Rheinische Friedrich-Wilhelms-Univ., Bonn (Germany). Inst. fuer Informatik II; Lades, M. [Bochum Univ. (Germany). Inst. fuer Neuroinformatik; Eeckman, F. [Lawrence Livermore National Lab., CA (United States)

    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.

  7. Silicon on ceramic process. Silicon sheet growth development for the Large-Area Silicon Sheet Task of the Low-Cost Silicon Solar Array Project. Annual report No. 2, September 17, 1976--September 19, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Zook, J.D.; Heaps, J.D.; Maciolek, R.B.; Koepke, B.; Butter, C.D.; Schuldt, S.B.

    1977-09-30

    The objective of this research program is to investigate the technical and economic feasibility of producing solar-cell-quality sheet silicon by coating one surface of carbonized ceramic substrates with a thin layer of large-grain polycrystalline silicon from the melt. In the past year significant progress was made in all areas of the program. The physical and chemical properties of the standard mullite refractory used for the majority of the coating runs (McDanel MV20 and Coors S1SI) have been characterized. A number of experimental compositions have been identified and procured from Coors. Characterization of the standard compositions revealed that the thermal expansion of mullite depends on both relative amounts of glass phase and on the impurity level in the glass. Since the thermal expansion in mullite exceeds that of silicon, the silicon coating should be in a state of compression. This was confirmed by x-ray measurements. After modifying and cleaning the dip-coating facility, silicon on ceramic (SOC) solar cells were fabricated which demonstrate that the SOC process can produce silicon of solar cell quality. SOC cells having 1 cm/sup 2/ active areas demonstrated measured conversion efficiencies as high as 7.2 percent. Typical open-ciruit voltages (V/sub oc/) and short-circuit current densities (J/sub sc/) were 0.51 volt and 20 mA/cm/sup 2/, respectively. Since the active surface of these solar cells is a highly reflective ''as-grown'' surface, one can expect improvement in J/sub sc/ after an anti-reflection (AR) coating is applied. Results of an economic analysis of the SOC process are presented.

  8. Silicon photonics manufacturing.

    Science.gov (United States)

    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.

  9. Silicon photonics fundamentals and devices

    CERN Document Server

    Deen, M Jamal

    2012-01-01

    The creation of affordable high speed optical communications using standard semiconductor manufacturing technology is a principal aim of silicon photonics research. This would involve replacing copper connections with optical fibres or waveguides, and electrons with photons. With applications such as telecommunications and information processing, light detection, spectroscopy, holography and robotics, silicon photonics has the potential to revolutionise electronic-only systems. Providing an overview of the physics, technology and device operation of photonic devices using exclusively silicon and related alloys, the book includes: * Basic Properties of Silicon * Quantum Wells, Wires, Dots and Superlattices * Absorption Processes in Semiconductors * Light Emitters in Silicon * Photodetectors , Photodiodes and Phototransistors * Raman Lasers including Raman Scattering * Guided Lightwaves * Planar Waveguide Devices * Fabrication Techniques and Material Systems Silicon Photonics: Fundamentals and Devices outlines ...

  10. Stabilization of elusive silicon oxides.

    Science.gov (United States)

    Wang, Yuzhong; Chen, Mingwei; Xie, Yaoming; Wei, Pingrong; Schaefer, Henry F; Schleyer, Paul von R; Robinson, Gregory H

    2015-06-01

    Molecular SiO2 and other simple silicon oxides have remained elusive despite the indispensable use of silicon dioxide materials in advanced electronic devices. Owing to the great reactivity of silicon-oxygen double bonds, as well as the low oxidation state of silicon atoms, the chemistry of simple silicon oxides is essentially unknown. We now report that the soluble disilicon compound, L:Si=Si:L (where L: = :C{N(2,6-(i)Pr2C6H3)CH}2), can be directly oxidized by N2O and O2 to give the carbene-stabilized Si2O3 and Si2O4 moieties, respectively. The nature of the silicon oxide units in these compounds is probed by spectroscopic methods, complementary computations and single-crystal X-ray diffraction.

  11. Radiation Hardening of Silicon Detectors

    CERN Multimedia

    Leroy, C; Glaser, M

    2002-01-01

    %RD48 %title\\\\ \\\\Silicon detectors will be widely used in experiments at the CERN Large Hadron Collider where high radiation levels will cause significant bulk damage. In addition to increased leakage current and charge collection losses worsening the signal to noise, the induced radiation damage changes the effective doping concentration and represents the limiting factor to long term operation of silicon detectors. The objectives are to develop radiation hard silicon detectors that can operate beyond the limits of the present devices and that ensure guaranteed operation for the whole lifetime of the LHC experimental programme. Radiation induced defect modelling and experimental results show that the silicon radiation hardness depends on the atomic impurities present in the initial monocrystalline material.\\\\ \\\\ Float zone (FZ) silicon materials with addition of oxygen, carbon, nitrogen, germanium and tin were produced as well as epitaxial silicon materials with epilayers up to 200 $\\mu$m thickness. Their im...

  12. Detection of Organic Vapors Based on Photoluminescent Bragg-Reflective Porous Silicon Interferomete.

    Science.gov (United States)

    Ahn, Jihoon; Cho, Bomin; Kim, Sungsoo; Sohn, Honglae

    2015-07-01

    Novel photoluminescent Bragg-reflective porous silicon, exhibiting dual optical properties, both the optical reflectivity and photoluminescence, was developed and used for sensing organic vapors. Photoluminescent Bragg-reflective porous silicon samples were prepared by an electrochemical etch of n-type silicon under the illumination. The etching solution consisted of a 3:1 volume mixture of aqueous 48% hydrofluoric acid and absolute ethanol. The typical etch parameters for the generation of photoluminescent Bragg-reflective porous silicon involved a periodic square wave current with 50 repeats. The surface of photoluminescent Bragg-reflective porous silicon was characterized by a FT-IR spectroscopy. Both reflectivity and photoluminescence were simultaneously measured under the exposure of organic vapors. The shift of reflection band to the longer wavelength and the quenching of photoluminescence under the exposure of various organic vapors were observed.

  13. European Community Can Reduce CO2 Emissions by Sixty Percent : A Feasibility Study

    NARCIS (Netherlands)

    Mot, E.; Bartelds, H.; Esser, P.M.; Huurdeman, A.J.M.; Laak, P.J.A. van de; Michon, S.G.L.; Nielen, R.J.; Baar, H.J.W. de

    1993-01-01

    Carbon dioxide (CO2) emissions in the European Community (EC) can be reduced by roughly 60 percent. A great many measures need to be taken to reach this reduction, with a total annual cost of ECU 55 milliard. Fossil fuel use is the main cause of CO2 emissions into the atmosphere; CO2 emissions are t

  14. Five Percent Post Survey Check Of National Family Health Survey (NFHS In ORISSA

    Directory of Open Access Journals (Sweden)

    Kumar Benera Sudhir

    1999-01-01

    Full Text Available Research questions: How well a post survey sample check of NFHS correlates with the findings of NFHS? Objective: Post survey check of National Family Health Survey carried out in 1992-93. Study design: Multistage sampling method with 5 percent sample of original NFHS sample. Setting: Study covered 5 percent sample of original NFHS sample. Subjects: Five percent household sample (1093 members of original NFHS sample was studied and compared with NFHS data. Method: Information from five percent house-holds of NFHS in which either there likely to be no change was likely to be only in one direction such as age group, sex-ratio, literacy, family planning knowledge and adoption etc. were collected in a predesigned questionnaire and compared with NFHS data. Results: The demographic characteristics were similar to those of NFHS. TFR and number of children ever borne were also found to be same. The awareness of FP methods and its uses were within acceptable margin of error. Thus on comparison of data of post survey check and NFHS sample error was within acceptable margin.

  15. After-Tax Profit of Kenya Airways for 2010-11 Financial Year Increases 73 Percent

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Kenya Airways is the pride of the whole African continent.Recently,Kenya Airways announced its after-tax profits for the 2010-11 fiscal yearincreased 73 percent.The airline’s CEO and General Manager Titus Naikuni attributes the greatest part of the

  16. 13 CFR 107.1410 - Requirement to redeem 4 percent Preferred Securities.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Requirement to redeem 4 percent Preferred Securities. 107.1410 Section 107.1410 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION SMALL BUSINESS INVESTMENT COMPANIES SBA Financial Assistance for Licensees (Leverage)...

  17. 13 CFR 107.1400 - Dividends or partnership distributions on 4 percent Preferred Securities.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Dividends or partnership distributions on 4 percent Preferred Securities. 107.1400 Section 107.1400 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION SMALL BUSINESS INVESTMENT COMPANIES SBA Financial Assistance for...

  18. 13 CFR 107.1420 - Articles requirements for 4 percent Preferred Securities.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Articles requirements for 4 percent Preferred Securities. 107.1420 Section 107.1420 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION SMALL BUSINESS INVESTMENT COMPANIES SBA Financial Assistance for Licensees (Leverage)...

  19. Introducing High School Students to NMR Spectroscopy through Percent Composition Determination Using Low-Field Spectrometers

    Science.gov (United States)

    Bonjour, Jessica L.; Pitzer, Joy M.; Frost, John A.

    2015-01-01

    Mole to gram conversions, density, and percent composition are fundamental concepts in first year chemistry at the high school or undergraduate level; however, students often find it difficult to engage with these concepts. We present a simple laboratory experiment utilizing portable nuclear magnetic resonance spectroscopy (NMR) to determine the…

  20. Clinician Percent Syllables Stuttered, Clinician Severity Ratings and Speaker Severity Ratings: Are They Interchangeable?

    Science.gov (United States)

    Karimi, Hamid; Jones, Mark; O'Brian, Sue; Onslow, Mark

    2014-01-01

    Background: At present, percent syllables stuttered (%SS) is the gold standard outcome measure for behavioural stuttering treatment research. However, ordinal severity rating (SR) procedures have some inherent advantages over that method. Aims: To establish the relationship between Clinician %SS, Clinician SR and self-reported Speaker SR. To…

  1. Generalized equations for estimating DXA percent fat of diverse young women and men: The Tiger Study

    Science.gov (United States)

    Popular generalized equations for estimating percent body fat (BF%) developed with cross-sectional data are biased when applied to racially/ethnically diverse populations. We developed accurate anthropometric models to estimate dual-energy x-ray absorptiometry BF% (DXA-BF%) that can be generalized t...

  2. Field method to measure changes in percent body fat of young women: The TIGER Study

    Science.gov (United States)

    Body mass index (BMI), waist (W) and hip (H) circumference (C) are commonly used to assess changes in body composition for field research. We developed a model to estimate changes in dual energy X-ray absorption (DXA) percent fat (% fat) from these variables with a diverse sample of young women fro...

  3. PETROCHINA'S OIL AND GAS PRODUCTION GROWS 5.3 PERCENT IN FIRST THREE QUARTERS

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ PetroChina announced its business results of the first three quarters of 2005 in mid-October. Based on the statistical figures made available from China's No. 1 oil producer, the January-September oil and gas production targets rose 5.3 percent as compared to the same period of the previous year.

  4. A Collaborative Endeavour between Mathematics and Science Educators: Focus on the Use of Percent in Chemistry

    Science.gov (United States)

    Ramful, Ajay; Bedgood, Danny; Lowrie, Thomas

    2016-01-01

    This paper is the outcome of a collaborative endeavour between mathematics and science educators where the insight from each field mutually informed one another. Specifically, building on the knowledge base from mathematics education research, this study analyses the ways in which percent is interpreted by first year university students in general…

  5. The Determination of the Percent of Oxygen in Air Using a Gas Pressure Sensor

    Science.gov (United States)

    Gordon, James; Chancey, Katherine

    2005-01-01

    The experiment of determination of the percent of oxygen in air is performed in a general chemistry laboratory in which students compare the results calculated from the pressure measurements obtained with the calculator-based systems to those obtained in a water-measurement method. This experiment allows students to explore a fundamental reaction…

  6. New Twists Mark the Debate over Texas' Top 10-Percent Plan

    Science.gov (United States)

    Schmidt, Peter

    2008-01-01

    Born out of one legal battle over affirmative action, the Texas college-admissions policy known as the "top 10 percent plan" is now at the center of another. The University of Texas at Austin is being challenged in U.S. District Court over its 2004 decision to return to using race-conscious admissions criteria after years without them.…

  7. 5 CFR 2636.304 - The 15 percent limitation on outside earned income.

    Science.gov (United States)

    2010-01-01

    ... ETHICS LIMITATIONS ON OUTSIDE EARNED INCOME, EMPLOYMENT AND AFFILIATIONS FOR CERTAIN NONCAREER EMPLOYEES Outside Earned Income Limitation and Employment and Affiliation Restrictions Applicable to Certain... calendar year which exceeds 15 percent of the annual rate of basic pay for level II of the...

  8. 26 CFR 1.382-3 - Definitions and rules relating to a 5-percent shareholder.

    Science.gov (United States)

    2010-04-01

    ... that, instead of an investment advisor recommending that clients purchase L stock, the trustee of... 26 Internal Revenue 4 2010-04-01 2010-04-01 false Definitions and rules relating to a 5-percent shareholder. 1.382-3 Section 1.382-3 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE...

  9. Radial growth and percent of latewood in Scots pine provenance trials in Western and Central Siberia

    Directory of Open Access Journals (Sweden)

    S. R. Kuzmin

    2016-12-01

    Full Text Available Percent of latewood of Boguchany and Suzun Scots pine climatypes has been studied in two provenance trials (place of origin and trial place. For Boguchany climatype the place of origin is south taiga of Central Siberia (Krasnoyarsk Krai, the place of trial is forest-steppe zone of Western Siberia (Novosibirsk Oblast and vice versa for Suzun climatype – forest-steppe zone of Western Siberia is the place of origin, south taiga is the place of trial. Comparison of annual average values of latewood percent of Boguchany climatype in south taiga and forest-steppe revealed the same numbers – 19 %. Annual variability of this trait in south taiga is distinctly lower and equal to 17 %, in forest-steppe – 35 %. Average annual values of latewood percent of Suzun climatype in the place of origin and trial place are close (20 and 21 %. Variability of this trait for Suzun climatype is higher than for Boguchany and equal to 23 % in south taiga and 42 % in forest-steppe. Climatic conditions in southern taiga in Central Siberia in comparison with forest-steppe in Western Siberia make differences between climatypes stronger. Differences between climatypes are expressed in different age of maximal increments of diameter, different tree ring width and latewood percent values and in different latewood reaction to weather conditions.

  10. Identification of a novel percent mammographic density locus at 12q24.

    Science.gov (United States)

    Stevens, Kristen N; Lindstrom, Sara; Scott, Christopher G; Thompson, Deborah; Sellers, Thomas A; Wang, Xianshu; Wang, Alice; Atkinson, Elizabeth; Rider, David N; Eckel-Passow, Jeanette E; Varghese, Jajini S; Audley, Tina; Brown, Judith; Leyland, Jean; Luben, Robert N; Warren, Ruth M L; Loos, Ruth J F; Wareham, Nicholas J; Li, Jingmei; Hall, Per; Liu, Jianjun; Eriksson, Louise; Czene, Kamila; Olson, Janet E; Pankratz, V Shane; Fredericksen, Zachary; Diasio, Robert B; Lee, Adam M; Heit, John A; DeAndrade, Mariza; Goode, Ellen L; Vierkant, Robert A; Cunningham, Julie M; Armasu, Sebastian M; Weinshilboum, Richard; Fridley, Brooke L; Batzler, Anthony; Ingle, James N; Boyd, Norman F; Paterson, Andrew D; Rommens, Johanna; Martin, Lisa J; Hopper, John L; Southey, Melissa C; Stone, Jennifer; Apicella, Carmel; Kraft, Peter; Hankinson, Susan E; Hazra, Aditi; Hunter, David J; Easton, Douglas F; Couch, Fergus J; Tamimi, Rulla M; Vachon, Celine M

    2012-07-15

    Percent mammographic density adjusted for age and body mass index (BMI) is one of the strongest risk factors for breast cancer and has a heritable component that remains largely unidentified. We performed a three-stage genome-wide association study (GWAS) of percent mammographic density to identify novel genetic loci associated with this trait. In stage 1, we combined three GWASs of percent density comprised of 1241 women from studies at the Mayo Clinic and identified the top 48 loci (99 single nucleotide polymorphisms). We attempted replication of these loci in 7018 women from seven additional studies (stage 2). The meta-analysis of stage 1 and 2 data identified a novel locus, rs1265507 on 12q24, associated with percent density, adjusting for age and BMI (P = 4.43 × 10(-8)). We refined the 12q24 locus with 459 additional variants (stage 3) in a combined analysis of all three stages (n = 10 377) and confirmed that rs1265507 has the strongest association in the 12q24 region (P = 1.03 × 10(-8)). Rs1265507 is located between the genes TBX5 and TBX3, which are members of the phylogenetically conserved T-box gene family and encode transcription factors involved in developmental regulation. Understanding the mechanism underlying this association will provide insight into the genetics of breast tissue composition.

  11. Cryo-Etched Black Silicon for Use as Optical Black

    Science.gov (United States)

    Yee, Karl Y.; White, Victor E.; Mouroulis, Pantazis; Eastwood, Michael L.

    2011-01-01

    Stray light reflected from the surface of imaging spectrometer components in particular, the spectrometer slit degrade the image quality. A technique has been developed for rapid, uniform, and cost-effective black silicon formation based on inductively coupled plasma (ICP) etching at cryogenic temperatures. Recent measurements show less than 1-percent total reflectance from 350 2,500 nm of doped black silicon formed in this way, making it an excellent option for texturing of component surfaces for reduction of stray light. Oxygen combines with SF6 + Si etch byproducts to form a passivation layer atop the Si when the etch is performed at cryogenic temperatures. Excess flow of oxygen results in micromasking and the formation of black silicon. The process is repeatable and reliable, and provides control over etch depth and sidewall profile. Density of the needles can be controlled to some extent. Regions to be textured can be patterned lithographically. Adhesion is not an issue as the nanotips are part of the underlying substrate. This is in contrast to surface growth/deposition techniques such as carbon nanotubes (CNTs). The black Si surface is compatible with wet processing, including processing with solvents, the textured surface is completely inorganic, and it does not outgas. In radiometry applications, optical absorbers are often constructed using gold black or CNTs. This black silicon technology is an improvement for these types of applications.

  12. Geometrical metrology on vacuum cast silicone rubber form using computed tomography

    DEFF Research Database (Denmark)

    Pacurar, Ramona; Müller, Pavel; De Chiffre, Leonardo

    An investigation on geometrical measurements of silicone rubber cake form and polyamide molds using three measuring techniques - CMM, optical scanner and CT scanner - was carried out. The only measurand was diameter of a cone measured at specified levels. An uncertainty budget for all three techn...... and measuring of complicated features. In connection with the silicone rubber form, CT scanning could be also used for example for failure analysis, 3D volume analysis and other non-destructive and metrological analysis....

  13. Laboratory course on silicon sensors

    CERN Document Server

    Crescio, E; Roe, S; Rudge, A

    2003-01-01

    The laboratory course consisted of four different mini sessions, in order to give the student some hands-on experience on various aspects of silicon sensors and related integrated electronics. The four experiments were. 1. Characterisation of silicon diodes for particle detection 2. Study of noise performance of the Viking readout circuit 3. Study of the position resolution of a silicon microstrip sensor 4. Study of charge transport in silicon with a fast amplifier The data in the following were obtained during the ICFA school by the students.

  14. Single crystalline mesoporous silicon nanowires

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. Social Networks in Silicon Valley

    Institute of Scientific and Technical Information of China (English)

    Joseph Leu

    2006-01-01

    @@ Social network is a dominant, distinguishing characteristic of Silicon Valley. Because innovation entails coping with a high degree of uncertainty,such innovation is particularly dependent on networks.

  16. Large Brillouin Amplification in Silicon

    CERN Document Server

    Kittlaus, Eric A; Rakich, Peter T

    2015-01-01

    Strong Brillouin coupling has only recently been realized in silicon using a new class of optomechanical waveguides that yield both optical and phononic confinement. Despite these major advances, appreciable Brillouin amplification has yet to be observed in silicon. Using a new membrane-suspended silicon waveguide we report large Brillouin amplification for the first time, reaching levels greater than 5 dB for modest pump powers, and demonstrate a record low (5 mW) threshold for net amplification. This work represents a crucial advance necessary to realize high-performance Brillouin lasers and amplifiers in silicon.

  17. Renormalized Volume

    Science.gov (United States)

    Gover, A. Rod; Waldron, Andrew

    2017-09-01

    We develop a universal distributional calculus for regulated volumes of metrics that are suitably singular along hypersurfaces. When the hypersurface is a conformal infinity we give simple integrated distribution expressions for the divergences and anomaly of the regulated volume functional valid for any choice of regulator. For closed hypersurfaces or conformally compact geometries, methods from a previously developed boundary calculus for conformally compact manifolds can be applied to give explicit holographic formulæ for the divergences and anomaly expressed as hypersurface integrals over local quantities (the method also extends to non-closed hypersurfaces). The resulting anomaly does not depend on any particular choice of regulator, while the regulator dependence of the divergences is precisely captured by these formulæ. Conformal hypersurface invariants can be studied by demanding that the singular metric obey, smoothly and formally to a suitable order, a Yamabe type problem with boundary data along the conformal infinity. We prove that the volume anomaly for these singular Yamabe solutions is a conformally invariant integral of a local Q-curvature that generalizes the Branson Q-curvature by including data of the embedding. In each dimension this canonically defines a higher dimensional generalization of the Willmore energy/rigid string action. Recently, Graham proved that the first variation of the volume anomaly recovers the density obstructing smooth solutions to this singular Yamabe problem; we give a new proof of this result employing our boundary calculus. Physical applications of our results include studies of quantum corrections to entanglement entropies.

  18. Predicting fat percent by skinfolds in racial groups: Durnin and Womersley revisited.

    Science.gov (United States)

    Davidson, Lance E; Wang, Jack; Thornton, John C; Kaleem, Zafar; Silva-Palacios, Federico; Pierson, Richard N; Heymsfield, Steven B; Gallagher, Dympna

    2011-03-01

    Despite their widespread use in research and fitness settings, Durnin and Womersley's (DW) 1974 prediction equations using skinfold thickness to estimate body fat percent by hydrodensitometry have not been systematically evaluated in racial or ethnic groups using body fat percent measured by dual-energy x-ray absorptiometry (%BF(DXA)) as the standard. This cross-sectional, population-based study examined whether the DW skinfold equations predict %BF(DXA) in a large, multiracial sample. Four skinfold measures (biceps, triceps, subscapular, and suprailiac), other clinical anthropometrics, and %BF(DXA) were obtained from 1675 healthy adults, age 18-110 yr, who were classified into four racial or ethnic categories: Caucasian, African American, Hispanic, or Asian. Predicted body fat percent using DW equations was compared with %BF(DXA) and evaluated within race/ethnicity- and sex-specific groups. Mean body fat percent predicted by DW equations was significantly different from %BF(DXA) in four of eight race/ethnicity- and sex-specific groups, particularly in Asian women and African American men (3.3 and 2.4 percentage point overestimates, respectively, P < 0.0001). New linear regression equations were developed estimating %BF(DXA) specific to each race/ethnicity and sex group, using the original DW skinfold sites. Body weight, height, and waist circumference independently predicted fat percent and were also included in the new equations. The 1974 DW equations did not predict %BF(DXA) uniformly in all races or ethnicities. Using %BF(DXA) as the criterion measure, the original DW skinfold equations have been updated specific to sex and race/ethnicity while maintaining the DW options for a minimalistic model using fewer predictors.

  19. Diminishing returns from increased percent Bt cotton: the case of pink bollworm.

    Science.gov (United States)

    Huang, Yunxin; Wan, Peng; Zhang, Huannan; Huang, Minsong; Li, Zhaohua; Gould, Fred

    2013-01-01

    Regional suppression of pests by transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) has been reported in several cropping systems, but little is known about the functional relationship between the ultimate pest population density and the pervasiveness of Bt crops. Here we address this issue by analyzing 16 years of field data on pink bollworm (Pectinophora gossypiella) population density and percentage of Bt cotton in the Yangtze River Valley of China. In this region, the percentage of cotton hectares planted with Bt cotton increased from 9% in 2000 to 94% in 2009 and 2010. We find that as the percent Bt cotton increased over the years, the cross-year growth rate of pink bollworm from the last generation of one year to the first generation of the next year decreased. However, as the percent Bt cotton increased, the within-year growth rate of pink bollworm from the first to last generation of the same year increased, with a slope approximately opposite to that of the cross-year rates. As a result, we did not find a statistically significant decline in the annual growth rate of pink bollworm as the percent Bt cotton increased over time. Consistent with the data, our modeling analyses predict that the regional average density of pink bollworm declines as the percent Bt cotton increases, but the higher the percent Bt cotton, the slower the decline in pest density. Specifically, we find that 95% Bt cotton is predicted to cause only 3% more reduction in larval density than 80% Bt cotton. The results here suggest that density dependence can act against the decline in pest density and diminish the net effects of Bt cotton on suppression of pink bollworm in the study region. The findings call for more studies of the interactions between pest density-dependence and Bt crops.

  20. Sputtering and codeposition of silicon carbide with deuterium

    Science.gov (United States)

    Causey, Rion A.

    2003-03-01

    Due to its excellent thermal properties, silicon carbide is being considered as a possible plasma-facing material for fusion devices. If used as a plasma-facing material, the energetic hydrogen isotope ions and charge-exchanged neutrals escaping from the plasma will sputter the silicon carbide. To assess the tritium inventory problems that will be generated by the use of this material, it is necessary that we know the codeposition properties of the redeposited silicon carbide. To determine the codeposition properties, the deuterium plasma experiment at Sandia National Laboratories in Livermore, California has been used to directly compare the deuterium sputtering and codeposition of silicon carbide with that of graphite. A Penning discharge at a flux of 6×10 19 D/m 2 and an energy of ≈300 eV was used to sputter silicon and carbon from a pair of 0.05 m diameter silicon carbide disks. The removal rate of deuterium gas from the fixed volume of the system isolated from all other sources and sinks was used to measure the codeposition probability (probability that a hydrogen isotope atom will be removed through codeposition per ion striking the sample surface). A small catcher plate used to capture a fraction of the codeposited film was analyzed using Auger spectroscopy. This analysis showed the film to begin with a high carbon to silicon ratio due to preferential sputtering of the carbon. As the film became thicker, the ratio of the depositing material changed over to the (1:1) value that must eventually be attained.

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

    Science.gov (United States)

    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.

  2. 40 CFR 60.1450 - How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste?

    Science.gov (United States)

    2010-07-01

    ... curtain incinerators that burn 100 percent yard waste? 60.1450 Section 60.1450 Protection of Environment... Air Curtain Incinerators That Burn 100 Percent Yard Waste § 60.1450 How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste? (a) Use EPA Reference Method 9 in appendix A...

  3. 40 CFR 60.1445 - What are the emission limits for air curtain incinerators that burn 100 percent yard waste?

    Science.gov (United States)

    2010-07-01

    ... curtain incinerators that burn 100 percent yard waste? 60.1445 Section 60.1445 Protection of Environment... Air Curtain Incinerators That Burn 100 Percent Yard Waste § 60.1445 What are the emission limits for air curtain incinerators that burn 100 percent yard waste? If your air curtain incinerator...

  4. 40 CFR 60.1920 - What are the emission limits for air curtain incinerators that burn 100 percent yard waste?

    Science.gov (United States)

    2010-07-01

    ... curtain incinerators that burn 100 percent yard waste? 60.1920 Section 60.1920 Protection of Environment... or Before August 30, 1999 Model Rule-Air Curtain Incinerators That Burn 100 Percent Yard Waste § 60.1920 What are the emission limits for air curtain incinerators that burn 100 percent yard waste?...

  5. 40 CFR 62.15375 - What are the emission limits for air curtain incinerators that burn 100 percent yard waste?

    Science.gov (United States)

    2010-07-01

    ... curtain incinerators that burn 100 percent yard waste? 62.15375 Section 62.15375 Protection of Environment... Combustion Units Constructed on or Before August 30, 1999 Air Curtain Incinerators That Burn 100 Percent Yard Waste § 62.15375 What are the emission limits for air curtain incinerators that burn 100 percent...

  6. 40 CFR 60.1925 - How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste?

    Science.gov (United States)

    2010-07-01

    ... curtain incinerators that burn 100 percent yard waste? 60.1925 Section 60.1925 Protection of Environment... or Before August 30, 1999 Model Rule-Air Curtain Incinerators That Burn 100 Percent Yard Waste § 60.1925 How must I monitor opacity for air curtain incinerators that burn 100 percent yard waste? (a)...

  7. Silicon on insulator with active buried regions

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  9. Quadrennial Review of Military Compensation (6th). Executive Summary. Volumes 1 thru 1C, and Volumes 2 thru 3

    Science.gov (United States)

    1988-08-01

    CIVILIAN EARNINGS PROFILE: ENLISTED SOURCE: SYLLOGISTICS 2-24 6th ORNC Esport -Volum 11 participation and higher than that of civilian counterparts in...7-26 6th QRNC esport - Volume I m Eliminate the existing 80 percent limiltation onmeai/entertairment deductions incurred in connection with the

  10. Vinyl ether silicones

    Energy Technology Data Exchange (ETDEWEB)

    Herzig, C.; Dauth, J.; Deubzer, B.; Weis, J. [Wacker-Chemie GmbH, Burghausen (Germany)

    1995-12-01

    Siloxanes with vinyl ether groups are prepared by hydrosilylation reaction of dihydrosiloxanes with divinyl ethers in excess. Different stoichiometry, produces linear copolymers of different viscosities and double bond concentrations always with an active vinyl ether group at each chain end. Polymerisations triggered by UV light were done with mixtures of these compounds and a series of onium salts. Very fast cure is observed even with low doses at 290 nm. V.E. silicones are found to cure essentially quantitative. The comparison with other highly reactive cationic monomers revealed that compounds are among the fastest curing prepolymers in cationic chemistry.

  11. Silicon production process evaluations

    Science.gov (United States)

    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.

  12. Edgeless silicon pad detectors

    Science.gov (United States)

    Perea Solano, B.; Abreu, M. C.; Avati, V.; Boccali, T.; Boccone, V.; Bozzo, M.; Capra, R.; Casagrande, L.; Chen, W.; Eggert, K.; Heijne, E.; Klauke, S.; Li, Z.; Mäki, T.; Mirabito, L.; Morelli, A.; Niinikoski, T. O.; Oljemark, F.; Palmieri, V. G.; Rato Mendes, P.; Rodrigues, S.; Siegrist, P.; Silvestris, L.; Sousa, P.; Tapprogge, S.; Trocmé, B.

    2006-05-01

    We report measurements in a high-energy pion beam of the sensitivity of the edge region in "edgeless" planar silicon pad diode detectors diced through their contact implants. A large surface current on such an edge prevents the normal reverse biasing of the device, but the current can be sufficiently reduced by the use of a suitable cutting method, followed by edge treatment, and by operating the detector at low temperature. The depth of the dead layer at the diced edge is measured to be (12.5±8 stat..±6 syst.) μm.

  13. Edgeless silicon pad detectors

    Energy Technology Data Exchange (ETDEWEB)

    Perea Solano, B. [CERN, CH-1211 Geneva 23 (Switzerland)]. E-mail: blanca.perea.solano@cern.ch; Abreu, M.C. [LIP and University of Algarve, 8000 Faro (Portugal); Avati, V. [CERN, CH-1211 Geneva 23 (Switzerland); Boccali, T. [INFN Sez. di Pisa and Scuola Normale Superiore, Pisa (Italy); Boccone, V. [INFN Sez. di Genova and Universita di Genova, Genoa (Italy); Bozzo, M. [INFN Sez. di Genova and Universita di Genova, Genoa (Italy); Capra, R. [INFN Sez. di Genova and Universita di Genova, Genoa (Italy); Casagrande, L. [INFN Sez. di Roma 2 and Universita di Roma 2, Rome (Italy); Chen, W. [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Eggert, K. [CERN, CH-1211 Geneva 23 (Switzerland); Heijne, E. [CERN, CH-1211 Geneva 23 (Switzerland); Klauke, S. [CERN, CH-1211 Geneva 23 (Switzerland); Li, Z. [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Maeki, T. [Helsinki Institute of Physics, Helsinki (Finland); Mirabito, L. [CERN, CH-1211 Geneva 23 (Switzerland); Morelli, A. [INFN Sez. di Genova and Universita di Genova, Genoa (Italy); Niinikoski, T.O. [CERN, CH-1211 Geneva 23 (Switzerland); Oljemark, F. [Helsinki Institute of Physics, Helsinki (Finland); Palmieri, V.G. [Helsinki Institute of Physics, Helsinki (Finland); Rato Mendes, P. [LIP and University of Algarve, 8000 Faro (Portugal); Rodrigues, S. [LIP and University of Algarve, 8000 Faro (Portugal); Siegrist, P. [CERN, CH-1211 Geneva 23 (Switzerland); Silvestris, L. [INFN Sez. Di Bari, Bari (Italy); Sousa, P. [LIP and University of Algarve, 8000 Faro (Portugal); Tapprogge, S. [Helsinki Institute of Physics, Helsinki (Finland); Trocme, B. [Institut de Physique Nucleaire, Villeurbanne (France)

    2006-05-01

    We report measurements in a high-energy pion beam of the sensitivity of the edge region in 'edgeless' planar silicon pad diode detectors diced through their contact implants. A large surface current on such an edge prevents the normal reverse biasing of the device, but the current can be sufficiently reduced by the use of a suitable cutting method, followed by edge treatment, and by operating the detector at low temperature. The depth of the dead layer at the diced edge is measured to be (12.5{+-}8{sub stat.}.{+-}6{sub syst.}) {mu}m.

  14. The LHCb Silicon Tracker

    CERN Document Server

    Elsasser, Ch; Gallas Torreira, A; Pérez Trigo, A; Rodríguez Pérez, P; Bay, A; Blanc, F; Dupertuis, F; Haefeli, G; Komarov, I; Märki, R; Muster, B; Nakada, T; Schneider, O; Tobin, M; Tran, M T; Anderson, J; Bursche, A; Chiapolini, N; Saornil, S; Steiner, S; Steinkamp, O; Straumann, U; Vollhardt, A; Britsch, M; Schmelling, M; Voss, H; Okhrimenko, O; Pugatch, V

    2013-01-01

    The aim of the LHCb experiment is to study rare heavy quark decays and CP vio- lation with the high rate of beauty and charmed hadrons produced in $pp$ collisions at the LHC. The detector is designed as a single-arm forward spectrometer with excellent tracking and particle identification performance. The Silicon Tracker is a key part of the tracking system to measure the particle trajectories to high precision. This paper reports the performance as well as the results of the radiation damage monitoring based on leakage currents and on charge collection efficiency scans during the data taking in the LHC Run I.

  15. Light Emitting Porous Silicon

    Science.gov (United States)

    1993-05-01

    ml - mm m lm m ~ m m ThO report Page 14 preparation method which has been originally described by Wohler [23] leads to a bright yellow substance with...Solid State Commun. 81, 307 (1992). [221 H. Kautsky, and H. Zocher, Z. Phys. 9,267 (1992). L TNO report Page 28 [231 F. Wohler , Lieb. Ann. 127, 275 (1863...Netherlands Fax + 31 70 328 09 61 Phone + 31 70 326 42 21 TNO- report copy no. e FEL-93eo047r Lh Emitting Porous Silicon sitho(s): DTICHMi.P.Th

  16. Silicon carbide sewing thread

    Science.gov (United States)

    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.

  17. Silicon Valley Lifestyle

    Institute of Scientific and Technical Information of China (English)

    Joseph Leu

    2005-01-01

    @@ As we embrace the rapid developments of the new media age,competitiveness in the field of internet and computer technology is an increasingly crucial factor in stimulating new business,jobs and new industry in the region.Accelerating advancements in new media,internet,software and computer technologies offer new commercial opportunities and sources of economic revenue. Silicon Valley has been a model of the new age since its existence.While the dream place not only has a unique business model,but also has a very special lifestyle.

  18. Amazing 7-day, super-simple, scripted guide to teaching or learning percents

    CERN Document Server

    Hernandez, Lisa

    2014-01-01

    Welcome to The Amazing 7-Day, Super-Simple, Scripted Guide to Teaching or Learning Percents. I have attempted to do just what the title says: make learning percents super simple. I have also attempted to make it fun and even ear-catching. The reason for this is not that I am a frustrated stand-up comic, but because in my fourteen years of teaching the subject, I have come to realize that my jokes, even the bad ones, have a crazy way of sticking in my students' heads. And should I use a joke (even a bad one) repetitively, the associations become embedded in their brains, many times to their cha

  19. Austrian Business Cycle Theory: Are 100 Percent Reserves Sufficient to Prevent a Business Cycle?

    Directory of Open Access Journals (Sweden)

    Philipp Bagus

    2010-02-01

    Full Text Available Authors in the Austrian tradition have made the credit expansion of a fractional reserve banking system as the prime cause of business cycles. Authors such as Selgin (1988 and White (1999 have argued that a solution to this problem would be a free banking system. They maintain that the competition between banks would limit the credit expansion effectively. Other authors such as Rothbard (1991 and Huerta de Soto (2006 have gone further and advocated a 100 percent reserve banking system ruling out credit expansion altogether. In this article it is argued that a 100 percent reserve system can still bring about business cycles through excessive maturity mismatching between deposits and loans.

  20. Niobium - Silicon - Titanium

    Science.gov (United States)

    Bulanova, Marina; Fartushna, Iuliia

    This document is part of Volume 11 `Ternary Alloy Systems: Phase Diagrams, Crystallographic and Thermodynamic Data', Subvolume E `Refractory Metal Systems', of SpringerMaterials - Group IV `Physical Chemistry'.

  1. Silicon - Titanium - Vanadium

    Science.gov (United States)

    Bulanova, Marina; Fartushna, Julia

    This document is part of Volume 11 `Ternary Alloy Systems: Phase Diagrams, Crystallographic and Thermodynamic Data', Subvolume E `Refractory Metal Systems', of SpringerMaterials - Group IV `Physical Chemistry'.

  2. Impurity doping processes in silicon

    CERN Document Server

    Wang, FFY

    1981-01-01

    This book introduces to non-experts several important processes of impurity doping in silicon and goes on to discuss the methods of determination of the concentration of dopants in silicon. The conventional method used is the discussion process, but, since it has been sufficiently covered in many texts, this work describes the double-diffusion method.

  3. Hydrodynamic slip in silicon nanochannels

    Science.gov (United States)

    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.

  4. Low Cost Fabrication of Silicon Carbide Based Ceramics and Fiber Reinforced Composites

    Science.gov (United States)

    Singh, M.; Levine, S. R.

    1995-01-01

    A low cost processing technique called reaction forming for the fabrication of near-net and complex shaped components of silicon carbide based ceramics and composites is presented. This process consists of the production of a microporous carbon preform and subsequent infiltration with liquid silicon or silicon-refractory metal alloys. The microporous preforms are made by the pyrolysis of a polymerized resin mixture with very good control of pore volume and pore size thereby yielding materials with tailorable microstructure and composition. Mechanical properties (elastic modulus, flexural strength, and fracture toughness) of reaction-formed silicon carbide ceramics are presented. This processing approach is suitable for various kinds of reinforcements such as whiskers, particulates, fibers (tows, weaves, and filaments), and 3-D architectures. This approach has also been used to fabricate continuous silicon carbide fiber reinforced ceramic composites (CFCC's) with silicon carbide based matrices. Strong and tough composites with tailorable matrix microstructure and composition have been obtained. Microstructure and thermomechanical properties of a silicon carbide (SCS-6) fiber reinforced reaction-formed silicon carbide matrix composites are discussed.

  5. Comparison of the silicone oil removal rate between vitrectomy and manual syringe negative pressure approach.

    Science.gov (United States)

    Lin, Zhong; Wu, Rong Han; Zhou, Ye Hui

    2017-08-01

    The purpose of this study was to compare the silicone oil removal rate between vitrectomy and manual syringe negative pressure approach. Thirty-five silicone oil-filled eyes were enrolled and allocated for manual (n = 19) and vitrectomy (n = 16) removal approaches. For manual approach, a 10-ml syringe was connected to the 23-gauge cannula through a short section of blood transfusion tube. Removal was started after pulling and fixing the plunger to the end part. The syringe was pulled away immediately once the residual of silicone oil cannot be observed through the cornea. For vitrectomy approach, the only difference was the source of negative pressure, i.e., the blood transfusion tube was connected to the cannula directly to remove the silicone oil. Silicone oil removal rate was defined as the volume of silicone oil divided by the time taken for removal. The mean time taken for silicone oil removal was faster for manual approach than vitrectomy approach (4.13 ± 1.41 vs. 6.14 ± 1.49, p = 0.001). Furthermore, the silicone oil removal rate was larger for manual approach (1.42 ± 0.30 vs. 0.90 ± 0.16 ml/min, p oil removal. The manual approach is more convenient and efficient.

  6. Prediction of upper flammability limit percent of pure compounds from their molecular structures.

    Science.gov (United States)

    Gharagheizi, Farhad

    2009-08-15

    In this study, a quantitative structure-property relationship (QSPR) is presented to predict the upper flammability limit percent (UFLP) of pure compounds. The obtained model is a five parameters multi-linear equation. The parameters of the model are calculated only from chemical structure. The average absolute error and squared correlation coefficient of the obtained model over all 865 pure compounds used to develop the model are 9.7%, and 0.92, respectively.

  7. A 20 GHz, 70 watt, 48 percent efficient space communications TWT

    Science.gov (United States)

    McDermott, M. A.; Tamashiro, R. N.

    A space qualifiable helix traveling wave tube capable of producing saturated output power levels above 70 watts at 48 percent total efficiency has been developed for 20 GHz satellite communications systems. The design approach stresses high reliability consistent with high power and efficiency. Advanced construction features incorporated into the design are a five stage collector, an M-type dispenser cathode, and a dynamic velocity tapered (DVT) helix.

  8. Some Weeds Community Percent in Response to Pumice Application on Soil under Water Stress Conditions

    Directory of Open Access Journals (Sweden)

    Davoud Zarehaghi

    2016-02-01

    Full Text Available A factorial experiment (using RCBD design with three replications was conducted in 2014 at the University of Tabriz-Iran, in order to determine the effects of pumice application (P1, P2, P3 and P4: control, 30, 60 and 90 tons per ha on soil and water stress (I1, I2 and I3: 100%, 70% and 50% water requirement calculated from class A pan, respectively on dominante weeds community percent. Results showed that community percent of weed species changed as a result of water stress and pumice application on soil. Distributions of Chenopodium album and Malva sylvestris were sensitive to water stress but, Amaranthus retroflexus and Solanum nigrum were neutral to water stress. In contrast, Amaranthus retroflexus, Cardaria draba, Setaria viridis, Sisymbrium irio, Xanthium strumarium, Convolvulus arvensis and Salsola rigida distribution were resistant to water stress. Community percent of Chenopodium album as sensitive species to water stress and Salsola rigida as resistance species to water stress positively affected by pumice application especially under water stress condition. Amaranthus retroflexus, Xanthium strumarium and Convolvulus arvensis were positively affected by pumice application under well and limited water supply conditions. In contrast, Cardaria draba, Sisymbrium irio and Solanum nigrum negatively affected by pumice under water stress and it had positive effect on community of these species under well watering conditions. Thus, application of pumice and water stress are two factors which change weed community precent.

  9. Silicon-based visible and near-infrared optoelectric devices

    Energy Technology Data Exchange (ETDEWEB)

    Mazur, Eric; Carey, James Edward

    2016-03-01

    In one aspect, the present invention provides a silicon photodetector having a surface layer that is doped with sulfur inclusions with an average concentration in a range of about 0.5 atom percent to about 1.5 atom percent. The surface layer forms a diode junction with an underlying portion of the substrate. A plurality of electrical contacts allow application of a reverse bias voltage to the junction in order to facilitate generation of an electrical signal, e.g., a photocurrent, in response to irradiation of the surface layer. The photodetector exhibits a responsivity greater than about 1 A/W for incident wavelengths in a range of about 250 nm to about 1050 nm, and a responsivity greater than about 0.1 A/W for longer wavelengths, e.g., up to about 3.5 microns.

  10. Silicon-micromachined microchannel plates

    CERN Document Server

    Beetz, C P; Steinbeck, J; Lemieux, B; Winn, D R

    2000-01-01

    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 approx 0.5 to approx 25 mu m, 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 deg. C, also compatible with high-temperature brazing, and can be essentially hydrogen, water and radionuclide-free. Novel secondary emitters and cesiated photocathodes can be high-temperature deposite...

  11. Dip coating process. Silicon sheet growth development for the large-area silicon sheet task of the Low Cost Silicon Solar Array Project. Quarterly report No. 5, December 18, 1976--March 21, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Zook, J.D.; Heaps, J.D.; Maciolek, R.B.; Koepke, B.; Butter, C.D.; Schuldt, S.B.

    1977-03-31

    Ceramic substrates can be coated with a thin layer of large-grain polycrystalline silicon by a dip-coating process. The silicon-on-ceramic (SOC) material appears to be quite promising as a low-cost cell material but requires somewhat special fabrication procedure since the contacts to both the n- and p-layers are now made on the front surface. Solar cells have been made on SOC material and on single-crystal control samples. Photodiodes 0.01 to 0.1 cm/sup 2/ made on substrates coated with vitreous carbon prior to dip coating with silicon showed the best efficiency of SOC material to date, namely over 6 percent uncorrected and about 12 percent inherent efficiency. Etching procedures have indicated that the dislocation density varies from almost 10/sup 7/ cm/sup -2/ to almost dislocation-free material, assuming that all etch pits are due to dislocations. EBIC measurements procedures were also improved, and it was found that diodes appear to be fairly uniform in EBIC response. A new SOC coating facility is being designed which will coat larger substrates in a continuous manner. The purpose is to minimize the contamination problem by reducing the contact area of the substrate with molten silicon. By having much larger throughput, it will also demonstrate the scale-up potential of the silicon-on-ceramic process. Portions of the new facility are under construction. An attempt has been made to model the economics of a large-scale facility for coating ceramic panels with silicon. A first iteration based on available parameters estimates showed that major cost items were poly Si ($2.90 per square meter), labor and burden ($2.50 per square meter), and the ceramic substrate ($2.50 per square meter), for a total price of about $11 per square meter.

  12. Dynamic Moisture Sorption and Desorption in Fumed Silica-filled Silicone Foam

    Energy Technology Data Exchange (ETDEWEB)

    Trautschold, Olivia Carol [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-02

    Characterizing dynamic moisture sorption and desorption in fumed silica-filled silicone foam is necessary for determining material compatibilities and life predictions, particularly in sealed environments that may be exposed to a range of environmental conditions. Thermogravimetric analysis (TGA) and near infrared spectroscopy (NIR) were performed on S5470 fumed silica-filled silicone foam to determine the weight percent of moisture at saturation. Additionally, TGA was used to determine the time, temperature, and relative humidity levels required for sorption and desorption of physisorbed moisture in S5470.

  13. EFFECT OF MATRICES ON PERCENT EXTRACTION OF SILVER (II FROM BLACK/WHITE PRINTING PHOTOGRAPHIC WASTE USING EMULSION LIQUID MEMBRANE TECHNIQUE

    Directory of Open Access Journals (Sweden)

    Imam Santoso

    2010-06-01

    Full Text Available Extraction of silver (I has been studied from black/white printing photographic waste by emulsion liquid membrane technique. Composition emulsion at the membrane phase was cerosene as solvent, sorbitan monooleat (span 80 as surfactant, dimethyldioctadesyl-ammonium bromide as carrier and as internal phase was HNO3. Optimum condition was obtained: ratio of internal phase volume and membrane phase volume was 1:1 : concentration of surfactant was 2% (v/v : time of making emulsion was 20 second : rate of stiring emulsion was 1100 rpm : rest time emulsion was 3 second : rate of emulsion volume and external phase volume was 1:5 : emulsion contact rate 500 rpm : emulsion contact time was 40 second : concentration of silver thiosulfate as external phase was 100 ppm : pH of external phase was 3 and pH of internal phase was 1. Optimum condition was applied in silver(I extraction from black/white printing photographic waste. It was obtained 77.33% average which 56.06% silver (I average of internal phase and 22.66% in the external phase. Effect of matrices ion decreased silver(I percent extraction from 96,37% average to 77.33% average. Keyword: photographics waste, silver extraction

  14. All-Optical dc Nanotesla Magnetometry Using Silicon Vacancy Fine Structure in Isotopically Purified Silicon Carbide

    Directory of Open Access Journals (Sweden)

    D. Simin

    2016-07-01

    Full Text Available We uncover the fine structure of a silicon vacancy in isotopically purified silicon carbide (4H-^{28}SiC and reveal not yet considered terms in the spin Hamiltonian, originated from the trigonal pyramidal symmetry of this spin-3/2 color center. These terms give rise to additional spin transitions, which would be otherwise forbidden, and lead to a level anticrossing in an external magnetic field. We observe a sharp variation of the photoluminescence intensity in the vicinity of this level anticrossing, which can be used for a purely all-optical sensing of the magnetic field. We achieve dc magnetic field sensitivity better than 100  nT/sqrt[Hz] within a volume of 3×10^{-7}mm^{3} at room temperature and demonstrate that this contactless method is robust at high temperatures up to at least 500 K. As our approach does not require application of radio-frequency fields, it is scalable to much larger volumes. For an optimized light-trapping waveguide of 3  mm^{3}, the projection noise limit is below 100  fT/sqrt[Hz].

  15. All-Optical dc Nanotesla Magnetometry Using Silicon Vacancy Fine Structure in Isotopically Purified Silicon Carbide

    Science.gov (United States)

    Simin, D.; Soltamov, V. A.; Poshakinskiy, A. V.; Anisimov, A. N.; Babunts, R. A.; Tolmachev, D. O.; Mokhov, E. N.; Trupke, M.; Tarasenko, S. A.; Sperlich, A.; Baranov, P. G.; Dyakonov, V.; Astakhov, G. V.

    2016-07-01

    We uncover the fine structure of a silicon vacancy in isotopically purified silicon carbide (4H-28SiC) and reveal not yet considered terms in the spin Hamiltonian, originated from the trigonal pyramidal symmetry of this spin-3 /2 color center. These terms give rise to additional spin transitions, which would be otherwise forbidden, and lead to a level anticrossing in an external magnetic field. We observe a sharp variation of the photoluminescence intensity in the vicinity of this level anticrossing, which can be used for a purely all-optical sensing of the magnetic field. We achieve dc magnetic field sensitivity better than 100 nT /√{Hz } within a volume of 3 ×10-7m m3 at room temperature and demonstrate that this contactless method is robust at high temperatures up to at least 500 K. As our approach does not require application of radio-frequency fields, it is scalable to much larger volumes. For an optimized light-trapping waveguide of 3 mm3 , the projection noise limit is below 100 fT /√{Hz } .

  16. Silicon photonics for high-performance interconnection networks

    Science.gov (United States)

    Biberman, Aleksandr

    2011-12-01

    enables new sets of opportunities that we can leverage for performance gains, as well as new sets of challenges that we must solve. Leveraging its inherent compatibility with standard fabrication techniques of the semiconductor industry, combined with its capability of dense integration with advanced microelectronics, silicon photonics also offers a clear path toward commercialization through low-cost mass-volume production. Combining empirical validations of feasibility, demonstrations of massive performance gains in large-scale systems, and the potential for commercial penetration of silicon photonics, the impact of this work will become evident in the many decades that follow.

  17. Growth of silicon sheets from metallurgical-grade silicon

    Science.gov (United States)

    Ciszek, T.; Schietzelt, M.; Kazmerski, L. L.; Hurd, J. L.; Fernelius, B.

    1981-05-01

    Impure silicon is difficult to solidify in sheet form because of morphological proturberances which may result from constitutional supercooling. Sheet growth methods which require a specific crystallographic orientation or which are characterized by a narrow melt meniscus are most affected by this problem. The edge-supported pulling technique was applied to sheet growth of metallurgical grade silicon and DAR (Direct Arc Reactor) silicon. The 7 mm meniscus height associated with this technique allowed the growth of 5 cm wide sheets from both materials. In each case, the sheets were p-type.

  18. Silicon carbonitrides - a novel class of materials

    Energy Technology Data Exchange (ETDEWEB)

    Schoenfelder, H. (Max-Planck-Inst. of Metals Research, Lab. for Powder Metallurgy, Inst. of Materials Science, Stuttgart (Germany)); Aldinger, F. (Max-Planck-Inst. of Metals Research, Lab. for Powder Metallurgy, Inst. of Materials Science, Stuttgart (Germany)); Riedel, R. (Max-Planck-Inst. of Metals Research, Lab. for Powder Metallurgy, Inst. of Materials Science, Stuttgart (Germany) Univ. of Darmstadt, Inst. of Materials Science, Darmstadt (Germany))

    1993-11-01

    Silicon carbonitride monoliths derived from polymer powder compacts via polymer pyrolysis represent a new class of structural ceramic materials due to the complete coalescence of the powder particles during polymer decomposition and the formation of a uniform ceramic matrix free from any grain boundaries or secondary phases. The submicron pore channel system penetrating the material can be minimized in volume by infiltration of liquid polysilazane solution or by post-HIPing so that relative densities of 96 % can be reached. The monoliths are oxidation resistant up to 1600 C in air due to the formation of a highly pure silica oxidation layer and they exhibit a creep rate of 1.10[sup -6] s[sup -1] at 1650 C and 30 MPa load. Initially x-ray amorphous silicon carbonitride can be crystallized in nitrogen or in air to form Si[sub 3]N[sub 4]/SiC or Si[sub 3]N[sub 4]/SiC/C nanocomposites. (orig.).

  19. Volume reflection of ultrarelativistic particles in single crystals

    Directory of Open Access Journals (Sweden)

    V. A. Maisheev

    2007-08-01

    Full Text Available An analytical description of volume reflection of charged ultrarelativistic particles in bent single crystals is considered. The relation describing the angle of volume reflection as a function of the transversal energy is obtained. Different angle distributions of the scattered protons in single crystals are found. Results of calculations for 400 GeV protons scattered by the silicon single crystal are presented.

  20. Lipid membranes on nanostructured silicon.

    Energy Technology Data Exchange (ETDEWEB)

    Slade, Andrea Lynn; Lopez, Gabriel P. (University of New Mexico, Albuquerque, NM); Ista, Linnea K. (University of New Mexico, Albuquerque, NM); O' Brien, Michael J. (University of New Mexico, Albuquerque, NM); Sasaki, Darryl Yoshio; Bisong, Paul (University of New Mexico, Albuquerque, NM); Zeineldin, Reema R. (University of New Mexico, Albuquerque, NM); Last, Julie A.; Brueck, Stephen R. J. (University of New Mexico, Albuquerque, NM)

    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.

  1. High Density Through Silicon Via (TSV)

    CERN Document Server

    Rimskog, Magnus

    2008-01-01

    The Through Silicon Via (TSV) process developed by Silex provides down to 30 micrometers pitch for through wafer connections in up to 600 micrometers thick substrates. Integrated with MEMS designs it enables significantly reduced die size and true "Wafer Level Packaging" - features that are particularly important in consumer market applications. The TSV technology also enables integration of advanced interconnect functions in optical MEMS, sensors and microfluidic devices. In addition the Via technology opens for very interesting possibilities considering integration with CMOS processing. With several companies using the process already today, qualified volume manufacturing in place and a line-up of potential users, the process is becoming a standard in the MEMS industry. We provide a introduction to the via formation process and also present some on the novel solutions made available by the technology.

  2. Gas flow characteristics in straight silicon microchannels

    Institute of Scientific and Technical Information of China (English)

    丁英涛; 姚朝晖; 沈孟育

    2002-01-01

    Experiments have been conducted to investigate nitrogen gas flow characteristics through four trapezoidal sili-con microchannels with different hydraulic diameters. The volume flow rate and pressure ratio are measured in theexperiments. It is found that the friction coefficient is no longer a constant, which is different from the conventionaltheory. The characteristics are first explained by the theoretical analysis. A simplified rectangular model (rectangularstraight channel model) is then proposed. The experimental results are compared with the theoretical predictions basedon the simplified rectangular model and the two-dimensional flow between the parallel-plate model which was usuallyuse The difference between the experimental data and the theoretical predictions is found in the high-pressure ratiocasesx. The influence of the gas compressibility effect based on the Boltzmann gas kinetic analysis method is studiedto interpret the discrepancy. We discuss two important factors affecting the application extent of different predictionmodels.

  3. An experimental investigation of two 15 percent-scale wind tunnel fan-blade designs

    Science.gov (United States)

    Signor, David B.

    1988-01-01

    An experimental 3-D investigation of two fan-blade designs was conducted. The fan blades tested were 15 percent-scale models of blades to be used in the fan drive of the National Full-Scale Aerodynamic Complex at NASA Ames Research Center. NACA 65- and modified NACA 65-series sections incorporated increased thickness on the upper surface, between the leading edge and the one-half-chord position. Twist and taper were the same for both blade designs. The fan blades with modified 65-series sections were found to have an increased stall margin when they were compared with the unmodified blades.

  4. Effects of Percent Tree Canopy Density and DEM Misregistration on SRTM/NED Vegetation Height Estimates

    Directory of Open Access Journals (Sweden)

    George Miliaresis

    2009-04-01

    Full Text Available The U.S National Elevation Dataset and the NLCD 2001 landcover data were used to test the correlation between SRTM elevation values and the height of evergreen forest vegetation in the Klamath Mountains of California.Vegetation height estimates (SRTM-NED are valid only for the two out of eight (N, NE, E, SE, S, SW, W, NW geographic directions, due to NED and SRTM grid data misregistration. Penetration depths of SRTM radar were found to linearly correlate to tree percent canopy density.

  5. Observations of ferroelastic switching by Raman spectroscopy in 18-percent ceria-stabilized zirconia

    Science.gov (United States)

    Bolon, Amy; Munoz Saldana, Juan; Gentleman, Molly

    2011-03-01

    Ferroelastic switching has been shown to be responsible for significant increases in the toughness of tetragonal zirconia ceramics. Observations of switching and measurements of coercive stress have generally been limited to TEM studies on large single crystals. In this study we show that it is possible to observe ferroelastic switching in 18 mole-percent ceria stabilized zirconia using polarized confocal Raman spectroscopy. Observations were made on bulk polycrystalline samples indented with a standard Vicker's indent and exhibited reorientation of crystal domains along the crack as well as near the crack tip. Coercive stress measurements were made by loading the samples uniaxially while making measurements of domain orientation.

  6. Single crystalline mesoporous silicon nanowires

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Ideal anodization of silicon

    Energy Technology Data Exchange (ETDEWEB)

    Yamani, Z.; Thompson, W.H.; AbuHassan, L.; Nayfeh, M.H. [Department of Physics, University of Illinois at Urbana-Champaign, 1110 W. Green Street, Urbana, Illinois 61801 (United States)

    1997-06-01

    Silicon has been anodized such that the porous layer is passivated with a homogeneous stretching phase by incorporating H{sub 2}O{sub 2} in the anodization mixture. Fourier transform infrared spectroscopy measurements show that the Si{endash}H stretching mode oriented perpendicular to the surface at {approximately}2100cm{sup {minus}1} dominates the spectrum with negligible contribution from the bending modes in the 600{endash}900cm{sup {minus}1} region. Material analysis using Auger electron spectroscopy shows that the samples have very little impurities, and that the luminescent layer is very thin (5{endash}10 nm). Scanning electron microscopy shows that the surface is smoother with features smaller than those of conventional samples. {copyright} {ital 1997 American Institute of Physics.}

  8. Silicon force sensor

    Science.gov (United States)

    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.

  9. Monolithic silicon bolometers

    Science.gov (United States)

    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.

  10. Electrochemical characterization of carbon coated bundle-type silicon nanorod for anode material in lithium ion secondary batteries

    Energy Technology Data Exchange (ETDEWEB)

    Halim, Martin [Center for Energy Convergence, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Energy and Environmental Engineering, Korea University of Science and Technology, Gwahangno, Yuseong-gu, Daejeon, 305-333 (Korea, Republic of); Kim, Jung Sub [Center for Energy Convergence, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Department of Material Science & Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Choi, Jeong-Gil [Department of Chemical Engineering, Hannam University, 461-1 Junmin-dong, Yusung-gu, Taejon 305-811 (Korea, Republic of); Lee, Joong Kee, E-mail: leejk@kist.re.kr [Center for Energy Convergence, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Energy and Environmental Engineering, Korea University of Science and Technology, Gwahangno, Yuseong-gu, Daejeon, 305-333 (Korea, Republic of)

    2015-04-15

    Highlights: • Bundle-type silicon nanorods (BSNR) were synthesized by metal assisted chemical etching. • Novel bundle-type nanorods electrode showed self-relaxant characteristics. • The self-relaxant property was enhanced by increasing the silver concentration. • PAA binder enhanced the self-relaxant property of the silicon material. • Carbon coated BSNR (BSNR@C) has evidently provided better cycle performance. - Abstract: Nanostructured silicon synthesis by surface modification of commercial micro-powder silicon was investigated in order to reduce the maximum volume change over cycle. The surface of micro-powder silicon was modified using an Ag metal-assisted chemical etching technique to produce nanostructured material in the form of bundle-type silicon nanorods. The volume change of the electrode using the nanostructured silicon during cycle was investigated using an in-situ dilatometer. Our result shows that nanostructured silicon synthesized using this method showed a self-relaxant characteristic as an anode material for lithium ion battery application. Moreover, binder selection plays a role in enhancing self-relaxant properties during delithiation via strong hydrogen interaction on the surface of the silicon material. The nanostructured silicon was then coated with carbon from propylene gas and showed higher capacity retention with the use of polyacrylic acid (PAA) binder. While the nano-size of the pore diameter control may significantly affect the capacity fading of nanostructured silicon, it can be mitigated via carbon coating, probably due to the prevention of Li ion penetration into 10 nano-meter sized pores.

  11. Automated silicon module assembly for the CMS silicon tracker

    CERN Document Server

    Surrow, B

    2001-01-01

    The CMS silicon tracker requires the assembly of about 20000 individual silicon detector modules. To ensure the assembly of such an amount with high, reproducible quality, an automated procedure has been developed for module assembly based on a high-precision robotic positioning machine. This procedure allows a much higher throughput and will result in much reduced manpower requirements than for traditional manual techniques. (1 refs).

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

    Science.gov (United States)

    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.

  13. Acute pneumonitis secondary to subcutaneous silicone injection

    Directory of Open Access Journals (Sweden)

    Gopie P

    2011-06-01

    Full Text Available Priya Gopie, Sateesh Sakhamuri, Anu Sharma, Sanjeev Solomon, Surujpal TeelucksinghClinical Medical Sciences, University of the West Indies, St Augustine, TrinidadAbstract: Following silicone injection, end organ toxicity can occur. To our knowledge this report documents the first case of silicone embolization in the Caribbean and serves to highlight an emergent danger associated with its illicit use for cosmetic purposes in this region.Keywords: silicone, silicone embolism, silicone pneumonitis, alveolar hemorrhage, pneumonitis

  14. Silicon Holder For Molecular-Beam Epitaxy

    Science.gov (United States)

    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.

  15. Renormalized Volume

    CERN Document Server

    Gover, A Rod

    2016-01-01

    For any conformally compact manifold with hypersurface boundary we define a canonical renormalized volume functional and compute an explicit, holographic formula for the corresponding anomaly. For the special case of asymptotically Einstein manifolds, our method recovers the known results. The anomaly does not depend on any particular choice of regulator, but the coefficients of divergences do. We give explicit formulae for these divergences valid for any choice of regulating hypersurface; these should be relevant to recent studies of quantum corrections to entanglement entropies. The anomaly is expressed as a conformally invariant integral of a local Q-curvature that generalizes the Branson Q-curvature by including data of the embedding. In each dimension this canonically defines a higher dimensional generalization of the Willmore energy/rigid string action. We show that the variation of these energy functionals is exactly the obstruction to solving a singular Yamabe type problem with boundary data along the...

  16. Core-shell amorphous silicon-carbon nanoparticles for high performance anodes in lithium ion batteries

    Science.gov (United States)

    Sourice, Julien; Bordes, Arnaud; Boulineau, Adrien; Alper, John P.; Franger, Sylvain; Quinsac, Axelle; Habert, Aurélie; Leconte, Yann; De Vito, Eric; Porcher, Willy; Reynaud, Cécile; Herlin-Boime, Nathalie; Haon, Cédric

    2016-10-01

    Core-shell silicon-carbon nanoparticles are attractive candidates as active material to increase the capacity of Li-ion batteries while mitigating the detrimental effects of volume expansion upon lithiation. However crystalline silicon suffers from amorphization upon the first charge/discharge cycle and improved stability is expected in starting with amorphous silicon. Here we report the synthesis, in a single-step process, of amorphous silicon nanoparticles coated with a carbon shell (a-Si@C), via a two-stage laser pyrolysis where decomposition of silane and ethylene are conducted in two successive reaction zones. Control of experimental conditions mitigates silicon core crystallization as well as formation of silicon carbide. Auger electron spectroscopy and scanning transmission electron microscopy show a carbon shell about 1 nm in thickness, which prevents detrimental oxidation of the a-Si cores. Cyclic voltammetry demonstrates that the core-shell composite reaches its maximal lithiation during the first sweep, thanks to its amorphous core. After 500 charge/discharge cycles, it retains a capacity of 1250 mAh.g-1 at a C/5 rate and 800 mAh.g-1 at 2C, with an outstanding coulombic efficiency of 99.95%. Moreover, post-mortem observations show an electrode volume expansion of less than 20% and preservation of the nanostructuration.

  17. The solvation study of carbon, silicon and their mixed nanotubes in water solution.

    Science.gov (United States)

    Hashemi Haeri, Haleh; Ketabi, Sepideh; Hashemianzadeh, Seyed Majid

    2012-07-01

    Nanotubes are believed to open the road toward different modern fields, either technological or biological. However, the applications of nanotubes have been badly impeded for the poor solubility in water which is especially essential for studies in the presence of living cells. Therefore, water soluble samples are in demand. Herein, the outcomes of Monte Carlo simulations of different sets of multiwall nanotubes immersed in water are reported. A number of multi wall nanotube samples, comprised of pure carbon, pure silicon and several mixtures of carbon and silicon are the subjects of study. The simulations are carried out in an (N,V,T) ensemble. The purpose of this report is to look at the effects of nanotube size (diameter) and nanotube type (pure carbon, pure silicon or a mixture of carbon and silicon) variation on solubility of multiwall nanotubes in terms of number of water molecules in shell volume. It is found that the solubility of the multi wall carbon nanotube samples is size independent, whereas multi wall silicon nanotube samples solubility varies with diameter of the inner tube. The higher solubility of samples containing silicon can be attributed to the larger atomic size of silicon atom which provides more direct contact with the water molecules. The other affecting factor is the bigger inter space (the space between inner and outer tube) in the case of silicon samples. Carbon type multi wall nanotubes appeared as better candidates for transporting water molecules through a multi wall nanotube structure, while in the case of water adsorption problems it is better to use multi wall silicon nanotubes or a mixture of multi wall carbon/ silicon nanotubes.

  18. Studies of silicon carbide and silicon carbide nitride thin films

    Science.gov (United States)

    Alizadeh, Zhila

    Silicon carbide semiconductor technology is continuing to advance rapidly. The excellent physical and electronic properties of silicon carbide recently take itself to be the main focused power device material for high temperature, high power, and high frequency electronic devices because of its large band gap, high thermal conductivity, and high electron saturation drift velocity. SiC is more stable than Si because of its high melting point and mechanical strength. Also the understanding of the structure and properties of semiconducting thin film alloys is one of the fundamental steps toward their successful application in technologies requiring materials with tunable energy gaps, such as solar cells, flat panel displays, optical memories and anti-reflecting coatings. Silicon carbide and silicon nitrides are promising materials for novel semiconductor applications because of their band gaps. In addition, they are "hard" materials in the sense of having high elastic constants and large cohesive energies and are generally resistant to harsh environment, including radiation. In this research, thin films of silicon carbide and silicon carbide nitride were deposited in a r.f magnetron sputtering system using a SiC target. A detailed analysis of the surface chemistry of the deposited films was performed using x-ray photoelectron spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR) and Raman spectroscopy whereas structure and morphology was studied atomic force microscopy (AFM), and nonoindentation.

  19. Validation of a dual-cycle ergometer for exercise during 100 percent oxygen prebreathing

    Science.gov (United States)

    Wiegman, Janet F.; Ohlhausen, John H.; Webb, James T.; Pilmanis, Andrew A.

    1992-01-01

    A study has been designed to determine if exercise, while prebreathing 100 percent oxygen prior to decompression, can reduce the current resting-prebreathe time requirements for extravehicular activity and high altitude reconnaissance flight. For that study, a suitable exercise mode was required. Design considerations included space limitations, cost, pressure suit compatibility, ease and maintenance of calibration, accuracy of work output, and assurance that no significant mechanical advantage or disadvantage would be introduced into the system. In addition, the exercise device must enhance denitrogenation by incorporation of both upper and lower body musculature at high levels of oxygen consumption. The purpose of this paper is to describe the specially constructed, dual-cycle ergometer developed for simultaneous arm and leg exercise during prebreathing, and to compare maximal oxygen uptake obtained on the device to that obtained during leg-only cycle ergometry and treadmill testing. Results demonstrate the suitability of the dual-cycle ergometer as an appropriate tool for exercise research during 100 percent oxygen prebreathing.

  20. The effect of chemical treatment and compression percent on mechanical properties of Paulownia compressed wood

    Directory of Open Access Journals (Sweden)

    Mahboobeh Mehmandoost

    2014-11-01

    Full Text Available Since human creation up to now, wood has been discussed as an important organic material, therefore its maintain and optimum usage is a considerable problem. From one hand, with due attention to condition of forest in Iran, using fast growing specie Paulownia provides new way in wood industries. But from other hand, this specie with low density has low strength. One of the suggested ways to increase density of this wood is its impregnation by resin and to compress it. In this research it is tried to increase the penetrability and impregnation of Paulownia by using urea formaldehyde resin at first pretreatment and then compression should be done. In order to perform this process, two variables pretreatment and compression percent were defined that each of them had two levels. The pretreatment was performed by NaCl and NaOH and 40, 50% compression. Totally, 72 samples were prepared and after producing the compressed wood, the absorption percent and mechanical properties were evaluated which included compression parallel to grain, modulus of rupture, modulus of elasticity in bending and impact strength. The results showed that the provided mechanical properties and pretreatments samples with NaCl had most values of these properties in 40 and 50% compression levels.

  1. Validation of a dual-cycle ergometer for exercise during 100 percent oxygen prebreathing

    Science.gov (United States)

    Wiegman, Janet F.; Ohlhausen, John H.; Webb, James T.; Pilmanis, Andrew A.

    1992-01-01

    A study has been designed to determine if exercise, while prebreathing 100 percent oxygen prior to decompression, can reduce the current resting-prebreathe time requirements for extravehicular activity and high altitude reconnaissance flight. For that study, a suitable exercise mode was required. Design considerations included space limitations, cost, pressure suit compatibility, ease and maintenance of calibration, accuracy of work output, and assurance that no significant mechanical advantage or disadvantage would be introduced into the system. In addition, the exercise device must enhance denitrogenation by incorporation of both upper and lower body musculature at high levels of oxygen consumption. The purpose of this paper is to describe the specially constructed, dual-cycle ergometer developed for simultaneous arm and leg exercise during prebreathing, and to compare maximal oxygen uptake obtained on the device to that obtained during leg-only cycle ergometry and treadmill testing. Results demonstrate the suitability of the dual-cycle ergometer as an appropriate tool for exercise research during 100 percent oxygen prebreathing.

  2. Meeting the Challenge: The Prospect of Achieving 30 Percent Savings Through the Weatherization Assistance Program

    Energy Technology Data Exchange (ETDEWEB)

    Schweitzer, M.

    2002-05-31

    The U.S. Department of Energy's (DOE's) Weatherization Assistance Program has been installing energy-efficiency measures in low-income houses for over 25 years, achieving savings exceeding 30 percent of natural gas used for space heating. Recently, as part of its Weatherization Plus initiative, the Weatherization Assistance Program adopted the goal of achieving 30 percent energy savings for all household energy usage. The expansion of the Weatherization Assistance Program to include electric baseload components such as lighting and refrigerators provides additional opportunities for saving energy and meeting this ambitious goal. This report documents an Oak Ridge National Laboratory study that examined the potential savings that could be achieved by installing various weatherization measures in different types of dwellings throughout the country. Three different definitions of savings are used: (1) reductions in pre-weatherization expenditures; (2) savings in the amount of energy consumed at the house site, regardless of fuel type (''site Btus''); and (3) savings in the total amount of energy consumed at the source (''source Btus''), which reflects the fact that each Btu* of electricity consumed at the household level requires approximately three Btus to produce at the generation source. In addition, the effects of weatherization efforts on carbon dioxide (CO{sub 2}) emissions are examined.

  3. Role of percent peripheral tissue ablated on refractive outcomes following hyperopic LASIK

    Science.gov (United States)

    Stapleton, Fiona; Versace, Patrick

    2017-01-01

    Objectives To determine the effect of hyperopic laser in situ keratomileusis (H-LASIK) on corneal integrity, by investigating relationships between proportionate corneal tissue ablated and refractive outcomes at 3 months. Methods 18 eyes of 18 subjects treated with H-LASIK by Technolas 217c Excimer Laser were included in the study. Orbscan II Topography System was used to determine corneal volume and pachymetry 3mm temporally (3T). The volume of corneal tissue ablated was determined from the laser nomogram. Univariate associations between age, treatment, corneal volume, overall proportion of tissue removed, proportion of tissue removed at 3T, residual bed thickness at 3T and refractive outcomes 3 months post-LASIK were examined and independent factors associated with refractive outcomes determined using linear regression models. Results At 3 months post-LASIK, the mean difference to expected refractive outcome was -0.20 ± 0.64 (Range -2.00 to +1.00). In univariate analysis, difference to expected refractive outcome was associated with proportion of tissue removed at 3T (Pcorneal steepening. Future hyperopic LASIK procedures could consider proportionate volume of corneal tissue removed at 3T in addition to laser nomograms to achieve improved refractive outcomes. PMID:28151939

  4. Using a remote sensing-based, percent tree cover map to enhance forest inventory estimation

    Science.gov (United States)

    Ronald E. McRoberts; Greg C. Liknes; Grant M. Domke

    2014-01-01

    For most national forest inventories, the variables of primary interest to users are forest area and growing stock volume. The precision of estimates of parameters related to these variables can be increased using remotely sensed auxiliary variables, often in combination with stratified estimators. However, acquisition and processing of large amounts of remotely sensed...

  5. The CMS silicon strip tracker and its electronic readout

    CERN Document Server

    Friedl, M

    2001-01-01

    The Large Hadron Collider (LHC) at CERN (Geneva, CH) will be the world's biggest accelerator machine when operation starts in 2006. One of its four detector experiments is the Compact Muon Solenoid (CMS), consisting of a large-scale silicon tracker and electromagnetic and hadron calorimeters, all embedded in a solenoidal magnetic field of 4T, and a muon system surrounding the magnet coil. The Silicon Strip Tracker has a sensitive area of 206m sup 2 with 10 million analog channels which are read out at the collider frequency of 40 MHz. The building blocks of the CMS Tracker are the silicon sensors, APV amplifier ASICs, supporting front-end ASICs, analog and digital optical links as well as data processors and control units in the back-end. Radiation tolerance, readout speed and the huge data volume are challenging requirements. I have modeled the charge collection in silicon detectors which is discussed as well as the concepts of readout amplifiers with respect to the LHC requirements, including the deconvolut...

  6. Characterization of silicon-silicon carbide ceramic derived from carbon-carbon silicon carbide composites

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Vijay K. [Indian Institute of Technology, Varanasi (India). Dept. of Mechanical Engineering; Krenkel, Walter [Univ. of Bayreuth (Germany). Dept. of Ceramic Materials Engineering

    2013-04-15

    The main objective of the present work is to process porous silicon - silicon carbide (Si - SiC) ceramic by the oxidation of carboncarbon silicon carbide (C/C - SiC) composites. Phase studies are performed on the oxidized porous composite to examine the changes due to the high temperature oxidation. Further, various characterization techniques are performed on Si- SiC ceramics in order to study the material's microstructure. The effects of various parameters such as fiber alignment (twill weave and short/chopped fiber) and phenolic resin type (resol and novolak) are characterized.

  7. Imprinted silicon-based nanophotonics

    DEFF Research Database (Denmark)

    Borel, Peter Ingo; Olsen, Brian Bilenberg; Frandsen, Lars Hagedorn

    2007-01-01

    We demonstrate and optically characterize silicon-on-insulator based nanophotonic devices fabricated by nanoimprint lithography. In our demonstration, we have realized ordinary and topology-optimized photonic crystal waveguide structures. The topology-optimized structures require lateral pattern ...

  8. Scattering characteristics from porous silicon

    Directory of Open Access Journals (Sweden)

    R. Sabet-Dariani

    2000-12-01

    Full Text Available   Porous silicon (PS layers come into existance as a result of electrochemical anodization on silicon. Although a great deal of research has been done on the formation and optical properties of this material, the exact mechanism involved is not well-understood yet.   In this article, first, the optical properties of silicon and porous silicon are described. Then, previous research and the proposed models about reflection from PS and the origin of its photoluminescence are reveiwed. The reflecting and scattering, absorption and transmission of light from this material, are then investigated. These experiments include,different methods of PS sample preparation their photoluminescence, reflecting and scattering of light determining different characteristics with respect to Si bulk.

  9. The History of Silicon Valley

    Institute of Scientific and Technical Information of China (English)

    Joseph Leu

    2005-01-01

    @@ Just as Manchester was once the center for indus trial progress, the microelectronics industry also has a heartland. Silicon Valley is located in a thirty by ten miles strip between San Francisco and San Jose,California.

  10. Optical information capacity of silicon

    CERN Document Server

    Dimitropoulos, Dimitris

    2014-01-01

    Modern computing and data storage systems increasingly rely on parallel architectures where processing and storage load is distributed within a cluster of nodes. The necessity for high-bandwidth data links has made optical communication a critical constituent of modern information systems and silicon the leading platform for creating the necessary optical components. While silicon is arguably the most extensively studied material in history, one of its most important attributes, an analysis of its capacity to carry optical information, has not been reported. The calculation of the information capacity of silicon is complicated by nonlinear losses, phenomena that emerge in optical nanowires as a result of the concentration of optical power in a small geometry. Nonlinear losses are absent in silica glass optical fiber and other common communication channels. While nonlinear loss in silicon is well known, noise and fluctuations that arise from it have never been considered. Here we report sources of fluctuations...

  11. Ultra-fast silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Sadrozinski, H. F.-W., E-mail: hartmut@scipp.ucsc.edu [Santa Cruz Institute for Particle Physics, UC Santa Cruz, Santa Cruz, CA 95064 (United States); Ely, S.; Fadeyev, V.; Galloway, Z.; Ngo, J.; Parker, C.; Petersen, B.; Seiden, A.; Zatserklyaniy, A. [Santa Cruz Institute for Particle Physics, UC Santa Cruz, Santa Cruz, CA 95064 (United States); Cartiglia, N.; Marchetto, F. [INFN Torino, Torino (Italy); Bruzzi, M.; Mori, R.; Scaringella, M.; Vinattieri, A. [University of Florence, Department of Physics and Astronomy, Sesto Fiorentino, Firenze (Italy)

    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 and D topics are discussed. -- Highlights: •We are proposing thin pixel silicon sensors with 10's of picoseconds time resolution. •Fast charge collection is coupled with internal charge multiplication. •The truly 4-D sensors will revolutionize imaging and particle counting in many applications.

  12. Silicon Drift Detectors for ALICE

    CERN Document Server

    Navach, F; CERN. Geneva

    1992-01-01

    The Silicon Drift Detector (SDD) is a semiconductor, not yet extensively used in HEP experiment, which has an excellent spatial resolution and granularity about comparable to a pixel device requiring a number of readout channels two order of magnitude less.

  13. Social Networks in Silicon Valley

    Institute of Scientific and Technical Information of China (English)

    Joseph; Leu

    2006-01-01

      Social network is a dominant, distinguishing characteristic of Silicon Valley. Because innovation entails coping with a high degree of uncertainty,such innovation is particularly dependent on networks.……

  14. Evanescent field phase shifting in a silicon nitride waveguide using a coupled silicon slab

    DEFF Research Database (Denmark)

    Jensen, Asger Sellerup; Oxenløwe, Leif Katsuo; Green, William M. J.

    2015-01-01

    An approach for electrical modulation of low-loss silicon nitride waveguides is proposed, using a silicon nitride waveguide evanescently loaded with a thin silicon slab. The thermooptic phase-shift characteristics are investigated in a racetrack resonator configuration.......An approach for electrical modulation of low-loss silicon nitride waveguides is proposed, using a silicon nitride waveguide evanescently loaded with a thin silicon slab. The thermooptic phase-shift characteristics are investigated in a racetrack resonator configuration....

  15. Effect of hydrofluoric acid (HF) concentration to pores size diameter of silicon membrane.

    Science.gov (United States)

    Burham, Norhafizah; Hamzah, Azrul Azlan; Majlis, Burhanuddin Yeop

    2014-01-01

    This paper studies parameters which affect the pore size diameter of a silicon membrane. Electrochemical etching is performed in characterise the parameter involved in this process. The parameter has been studied is volume ratio of hydrofluoric acid (HF) and ethanol as an electrolyte aqueous for electrochemical etch. This electrolyte aqueous solution has been mixed between HF and ethanol with volume ratio 3:7, 5:5, 7:3 and 9:1. As a result, the higher volume of HF in this electrolyte gives the smallest pore size diameter compared to the lower volume of HF. These samples have been dipped into HF and ethanol electrolyte aqueous with supplied 25 mA/cm2 current density for 20, 30, 40, and 50 minutes. The samples will inspect under Scanning Electron Microscope (SEM) to execute the pore formations on silicon membrane surface.

  16. Silicone-Rubber Stitching Seal

    Science.gov (United States)

    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.

  17. Silicon superconducting quantum interference device

    Energy Technology Data Exchange (ETDEWEB)

    Duvauchelle, J. E.; Francheteau, A.; Marcenat, C.; Lefloch, F., E-mail: francois.lefloch@cea.fr [Université Grenoble Alpes, CEA - INAC - SPSMS, F-38000 Grenoble (France); Chiodi, F.; Débarre, D. [Université Paris-sud, CNRS - IEF, F-91405 Orsay - France (France); Hasselbach, K. [Université Grenoble Alpes, CNRS - Inst. Néel, F-38000 Grenoble (France); Kirtley, J. R. [Center for probing at nanoscale, Stanford University, Palo Alto, California 94305-4045 (United States)

    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.

  18. Silicon Sensors for HEP Experiments

    CERN Document Server

    Dierlamm, Alexander Hermann

    2017-01-01

    With increasing luminosity of accelerators for experiments in High Energy Physics the demands on the detectors increase as well. Especially tracking and vertexing detectors made of silicon sensors close to the interaction point need to be equipped with more radiation hard devices. This article introduces the different types of silicon sensors, describes measures to increase radiation hardness and provides an overview of present upgrade choices of HEP experiments.

  19. Ocean Engineering Studies Compiled 1991. Volume 7. Acrylic Windows- Diverse Design Features and Types of Service

    Science.gov (United States)

    1991-01-01

    titanium hatches (Fig. 4) were inserted into the polar penetrations and scaled against leakage with room vulcanizing silicone rubber squirted into...higher than in the thick shell (0.31 versus 0.25 percent) (Table 5). Discussion Spherical Shell. The tesi results generated by the pressure cycling

  20. Performance of the CLAS12 Silicon Vertex Tracker modules

    Energy Technology Data Exchange (ETDEWEB)

    Antonioli, M.A.; Boiarinov, S.; Bonneau, P.; Elouadrhiri, L.; Eng, B. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Gotra, Y., E-mail: gotra@jlab.org [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Kurbatov, E. [Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow (Russian Federation); Leffel, M.; Mandal, S.; McMullen, M. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Merkin, M. [Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow (Russian Federation); Raydo, B.; Teachey, W. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Tucker, R. [Arizona State University, Tempe, AZ (United States); Ungaro, M.; Yegneswaran, A.; Ziegler, V. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2013-12-21

    For the 12 GeV upgrade, the CLAS12 experiment has designed a Silicon Vertex Tracker (SVT) using single sided microstrip sensors fabricated by Hamamatsu. The sensors have graded angle design to minimize dead areas and a readout pitch of 156μm, with intermediate strip. Double sided SVT module hosts three daisy-chained sensors on each side with a full strip length of 33 cm. There are 512 channels per module read out by four Fermilab Silicon Strip Readout (FSSR2) chips featuring data driven architecture, mounted on a rigid-flex hybrid. Modules are assembled on the barrel using unique cantilevered geometry to minimize the amount of material in the tracking volume. Design and performance of the SVT modules are presented, focusing on results of electrical measurements. -- Highlights: •A Silicon Vertex Tracker has been designed for the central tracker of the CLAS12 experiment. •Using cantilevered module geometry allows minimizing amount of material in the tracking volume. •A dedicated Hybrid Flex Circuit Board has been developed to read out double sided module. •Module performance meets design goals of the CLAS12 Central Tracker.

  1. Six Thousand Electrochemical Cycles of Double-Walled Silicon Nanotube Anodes for Lithium Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wu, H

    2011-08-18

    Despite remarkable progress, lithium ion batteries still need higher energy density and better cycle life for consumer electronics, electric drive vehicles and large-scale renewable energy storage applications. Silicon has recently been explored as a promising anode material for high energy batteries; however, attaining long cycle life remains a significant challenge due to materials pulverization during cycling and an unstable solid-electrolyte interphase. Here, we report double-walled silicon nanotube electrodes that can cycle over 6000 times while retaining more than 85% of the initial capacity. This excellent performance is due to the unique double-walled structure in which the outer silicon oxide wall confines the inner silicon wall to expand only inward during lithiation, resulting in a stable solid-electrolyte interphase. This structural concept is general and could be extended to other battery materials that undergo large volume changes.

  2. Long Wavelength Plasmonic Absorption Enhancement in Silicon Using Optical Lithography Compatible Core-Shell-Type Nanowires

    Directory of Open Access Journals (Sweden)

    Mohammed Shahriar Sabuktagin

    2014-01-01

    Full Text Available Plasmonic properties of rectangular core-shell type nanowires embedded in thin film silicon solar cell structure were characterized using FDTD simulations. Plasmon resonance of these nanowires showed tunability from  nm. However this absorption was significantly smaller than the Ohmic loss in the silver shell due to very low near-bandgap absorption properties of silicon. Prospect of improving enhanced absorption in silicon to Ohmic loss ratio by utilizing dual capability of these nanowires in boosting impurity photovoltaic effect and efficient extraction of the photogenerated carriers was discussed. Our results indicate that high volume fabrication capacity of optical lithography techniques can be utilized for plasmonic absorption enhancement in thin film silicon solar cells over the entire long wavelength range of solar radiation.

  3. Microstructural degradation of silicon electrodes during lithiation observed via operando X-ray tomographic imaging

    Science.gov (United States)

    Taiwo, Oluwadamilola O.; Paz-García, Juan M.; Hall, Stephen A.; Heenan, Thomas M. M.; Finegan, Donal P.; Mokso, Rajmund; Villanueva-Pérez, Pablo; Patera, Alessandra; Brett, Daniel J. L.; Shearing, Paul R.

    2017-02-01

    Due to their high theoretical capacity compared to that of state-of-the-art graphite-based electrodes, silicon electrodes have gained much research focus for use in the development of next generation lithium-ion batteries. However, a major drawback of silicon as an electrode material is that it suffers from particle fracturing due to huge volume expansion during electrochemical cycling, thus limiting commercialization of such electrodes. Understanding the role of material microstructure in electrode degradation will be instrumental in the design of stable silicon electrodes. Here, we demonstrate the application of synchrotron-based X-ray tomographic microscopy to capture and track microstructural evolution, phase transformation and fracturing within a silicon-based electrode during electrochemical lithiation.

  4. Confined silicon nanospheres by biomass lignin for stable lithium ion battery

    Science.gov (United States)

    Niu, Xiaoying; Zhou, Jinqiu; Qian, Tao; Wang, Mengfan; Yan, Chenglin

    2017-10-01

    Biomass lignin, as a significant renewable resource, is one of the most abundant natural polymers in the world. Here, we report a novel silicon-based material, in which lignin-derived functional conformal network crosslinks the silicon nanoparticles via self-assembly. This newly-developed material could greatly solve the problems of large volume change during lithiation/delithiation process and the formation of unstable solid electrolyte interphase layers on the silicon surface. With this anode, the battery demonstrates a high capacity of ∼3000 mA h g‑1, a highly stable cycling retention (∼89% after 100 cycles at 300 mA g‑1) and an excellent rate capability (∼800 mA h g‑1 at 9 A g‑1). Moreover, the feasibility of full lithium-ion batteries with the novel silicon-based material would provide wide range of applications in the field of flexible energy storage systems for wearable electronic devices.

  5. Research on the Fe-silicon nitride material self-producing N2 at high temperature

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The Fe-silicon nitride synthesized by flashing combustion process was studied to determine the reaction temperature between Fe and silicon nitride, the account of N2 given out in the course of the reaction, and the change of the microstructure during calcination. The results showed that at 1127.2℃ the Fe-silicon nitride self-reacts and releases N2 and under 101.3 kPa the volume of N2 given out in the course of the reaction is 20 times more than that of the starting material. N2 is produced quickly, and completes in several decade seconds. With the producing of N2, the structure of Silicon Nitride around Fe becomes loose and porous, or cracks are formed by the reaction between Fe and silicon nitride. So if it is made use of that Fe-silicon nitride self-producing N2 at the high temperature, the performance of the material on a base of Fe-silicon nitride could be greatly improved.

  6. Dependency of Electrochemical Performances of Silicon Lithium-Ion Batteries on Glycosidic Linkages of Polysaccharide Binders.

    Science.gov (United States)

    Yoon, Da-Eun; Hwang, Chihyun; Kang, Na-Ri; Lee, Ungju; Ahn, Dongjoon; Kim, Ju-Young; Song, Hyun-Kon

    2016-02-17

    Molecular structures of polysaccharide binders determining mechanical properties were correlated to electrochemical performances of silicon anodes for lithium-ion batteries. Glycosidic linkages (α and β) and side chains (-COOH and -OH) were selected and proven as the major factors of the molecular structures. Three different single-component polysaccharides were compared: pectin for α-linkages versus carboxylic methyl cellulose (CMC) for β-linkages from the linkage's standpoint, and pectin as a COOH-containing polymer and amylose as its non-COOH counterpart from the side chain's standpoint. Pectin was remarkably superior to CMC and amylose in cyclability and rate capability of battery cells based on silicon anodes. The pectin binder allowed volume expansion of silicon electrodes with keeping high porosity during lithiation due to the elastic nature caused by the chair-to-boat conformation in α-linkages of its backbone. Physical integrity of pectin-based electrodes was not challenged during repeated lithiation/delithiation cycles without crack development that was observed in rigid CMC-based electrodes. Covalent bonds formed between carboxylic side chains of pectin and silicon surface oxide prevented active silicon mass from being detached away from electric pathways. However, hydrogen bonds between hydroxyl side chains of amylose and silicon surface oxide were not strong enough to keep the silicon mass electrochemically active after cyclability tests.

  7. Dip coating process. Silicon sheet growth development for the large-area silicon sheet task of the low-cost silicon solar array project. Quarterly report No. 6, March 22, 1977--June 24, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Zook, J.D.; Heaps, J.D.; Maciolek, R.B.; Koepke, B.; Butter, C.D.; Schuldt, S.B.

    1977-06-30

    The objective of this research program is to investigate the technical and economic feasibility of producing solar-cell-quality sheet silicon by coating one surface of carbonized ceramic substrates with a thin layer of large-grain polycrystalline silicon from the melt. Significant progress was made in silicon on ceramic (SOC) solar cell performance. SOC cells having 1 cm/sup 2/ active areas demonstrated measured conversion efficiencies as high as 7.2 percent. Typical open circuit voltages (V/sub oc/) and short circuit current densities (J/sub sc/) were 0.51 volt and 20 mA/cm/sup 2/ respectively. Since the active surface of these solar cells is a highly reflective ''as-grown'' surface, one can expect improvement in J/sub sc/ after an anti-reflection (AR) coating is applied. It is significant that single-crystal comparison cells, also measured without benefit of an AR coating, had efficiencies in the 8.5 percent range with typical V/sub oc/'s and J/sub sc/'s of 0.54 volt and 23 mA/cm/sup 2/, respectively. Therefore, improvement in cell design and junction diffusion techniques should increase the efficiency of both the SOC and single-crystal cells. During this quarter the dip coating facility was inadvertently contaminated, but has since been restored to a purity level exceeding its original state. With this facility, silicon coatings were grown with a single-crystal seed attached to the substrate. Single-crystal silicon was not forthcoming, but the results were nonetheless encouraging. Several of the carbon coating types tried appear promising, including one which has high purity and can be applied uniformly by swab or airbrush.

  8. Tensile test of pressureless-sintered silicon nitride at elevated temperature

    Science.gov (United States)

    Matsusue, K.; Fujisawa, Y.; Takahara, K.

    1985-01-01

    Uniaxial tensile strength tests of pressureless sintered silicon nitride were carried out in air at temperatures ranging from room temperature up to 1600 C. Silicon nitrides containing Y2O3, Al2O3, Al2O3-MgO, or MgO-CeO2 additives were tested. The results show that the composition of the additive used influences the strength characteristics of the silicon nitride. The tensile strength rapidly decreased at temperatures above 1000 C for the materials containing MgO as the additive and above 1000 C for the material with Y2O3. When the temperature increased to as high as 1300 C, the strength decreased to about 10 percent of the room temperature strength in each case. Observations of the fracture origin and of the crack propagation on the fracture surfaces are discussed.

  9. Deposited low temperature silicon GHz modulator

    CERN Document Server

    Lee, Yoon Ho Daniel; Lipson, Michal

    2013-01-01

    The majority of silicon photonics is built on silicon-on-insulator (SOI) wafers while the majority of electronics, including CPUs and memory, are built on bulk silicon wafers, limiting broader acceptance of silicon photonics. This discrepancy is a result of silicon photonics's requirement for a single-crystalline silicon (c-Si) layer and a thick undercladding for optical guiding that bulk silicon wafers to not provide. While the undercladding problem can be partially addressed by substrate removal techniques, the complexity of co-integrating photonics with state-of-the-art transistors and real estate competition between electronics and photonics remain problematic. We show here a platform for deposited GHz silicon photonics based on polycrystalline silicon with high optical quality suitable for high performance electro-optic devices. We demonstrate 3 Gbps polysilicon electro-optic modulator fabricated on a deposited polysilicon layer fully compatible with CMOS backend integration. These results open up an arr...

  10. Direct Production of Silicones From Sand

    Energy Technology Data Exchange (ETDEWEB)

    Larry N. Lewis; F.J. Schattenmann: J.P. Lemmon

    2001-09-30

    Silicon, in the form of silica and silicates, is the second most abundant element in the earth's crust. However the synthesis of silicones (scheme 1) and almost all organosilicon chemistry is only accessible through elemental silicon. Silicon dioxide (sand or quartz) is converted to chemical-grade elemental silicon in an energy intensive reduction process, a result of the exceptional thermodynamic stability of silica. Then, the silicon is reacted with methyl chloride to give a mixture of methylchlorosilanes catalyzed by cooper containing a variety of tract metals such as tin, zinc etc. The so-called direct process was first discovered at GE in 1940. The methylchlorosilanes are distilled to purify and separate the major reaction components, the most important of which is dimethyldichlorosilane. Polymerization of dimethyldichlorosilane by controlled hydrolysis results in the formation of silicone polymers. Worldwide, the silicones industry produces about 1.3 billion pounds of the basic silicon polymer, polydimethylsiloxane.

  11. Silicon active photonic devices

    Science.gov (United States)

    Dimitropoulos, Dimitrios

    Active photonic devices utilizing the optical nonlinearities of silicon have emerged in the last 5 years and the effort for commercial photonic devices in the material that has been the workhorse of electronics has been building up since. This dissertation presents the theory for some of these devices. We are concerned herein with CW lasers, amplifiers and wavelength converters that are based on the Raman effect. There have already been cursory experimental demonstrations of these devices and some of their limitations are already apparent. Most of the limitations observed are because of the appearance of effects that are competing with stimulated Raman scattering. Under the high optical powers that are necessary for the Raman effect (tens to hundrends of mW's) the process of optical two-photon (TPA) absorption occurs. The absorption of optical power that it causes itself is weak but in the process electrons and holes are generated which can further absorb light through the free-carrier absorption effect (FCA). The effective "lifetime" that these carriers have determines the magnitude of the FCA loss. We present a model for the carrier lifetime in Silicon-On-Insulator (SOI) waveguides and numerical simulations to understand how this critical parameter varies and how it can be controlled. A p-i-n junction built along SOI waveguides can help achieve lifetime of the order of 20--100 ps but the price one has to pay is on-chip electrical power consumption on the order of 100's of mWs. We model CW Raman lasers and we find that the carrier lifetime reduces the output power. If the carrier lifetime exceeds a certain "critical" value optical losses become overwhelming and lasing is impossible. As we show, in amplifiers, the nonlinear loss does not only result in diminished gain, but also in a higher noise figure. Finally the effect of Coherent anti-Stokes Raman scattering (CARS) is examined. The effect is important because with a pump frequency at 1434nm coherent power

  12. Preparation and Characterization of Carbon Coated Silicon Nanoparticle as Anode Material for Li-ion Batteries

    Institute of Scientific and Technical Information of China (English)

    T. Zhancg; L.J. Fu; J. Gao; Y. P. Wu; H.Q. Wu

    2005-01-01

    @@ 1Introduction Silicon has been regarded as one of the most promising anode materials for Li-ion batteries. Its theoretical capacity (4 000 mAh/g) is much higher than that of the commercialized graphite (372 mAh/g)[1]. However,the cycle performance of silicon is poor due to the severe volume expansion and shrinkage during Li+ insertion/extraction which results in pulverization of Si particles, eventually losing its Li+ storage ability[2]. To solve this problem, nanosized Si particles were utilized and achieved a partial improvement by reducing the absolute volume change. Nevertheless, a new problem was encountered with nanosized material that small Si particles were aggregated to be larger one during Li+ insertion/extraction, and then pulverized again[3]. In this work, we have succeeded to improve the cycle performance of nanosized Si particles by synthesis of carbon coated silicon nanoparticle.

  13. Infrared Insight into the Network of Hydrogenated Amorphous and Polycrystalline Silicon thin Films

    Directory of Open Access Journals (Sweden)

    Jarmila Mullerova

    2006-01-01

    Full Text Available IR measurements were carried out on both amorphous and polycrystalline silicon samples deposited by PECVDon glass substrate. The transition from amorphous to polycrystalline phase was achieved by increasing dilution of silaneplasma at the deposition process. The samples were found to be mixed phase materials. Commonly, infrared spectra ofhydrogenated silicon thin films yield information about microstructure, hydrogen content and hydrogen bonding to silicon. Inthis paper, additional understanding was retrieved from infrared response. Applying standard optical laws, effective mediatheory and Clausius-Mossoti approach concerning the Si-Si and Si-H bonds under IR irradiation as individual oscillators,refractive indices in the long wavelength limit, crystalline, amorphous and voids volume fractions and the mass density of thefilms were determined. The mass density was found to decrease with increasing crystalline volume fraction, which can beattributed to the void-dominated mechanism of network formation.

  14. Transition aerodynamics for 20-percent-scale VTOL unmanned aerial vehicle

    Science.gov (United States)

    Kjerstad, Kevin J.; Paulson, John W., Jr.

    1993-01-01

    An investigation was conducted in the Langley 14- by 22-Foot Subsonic Tunnel to establish a transition data base for an unmanned aerial vehicle utilizing a powered-lift ejector system and to evaluate alterations to the ejector system for improved vehicle performance. The model used in this investigation was a 20-percent-scale, blended-body, arrow-wing configuration with integrated twin rectangular ejectors. The test was conducted from hover through transition conditions with variations in angle of attack, angle of sideslip, free-stream dynamic pressure, nozzle pressure ratio, and model ground height. Force and moment data along with extensive surface pressure data were obtained. A laser velocimeter technique for measuring inlet flow velocities was demonstrated at a single flow condition, and also a low order panel method was successfully used to numerically simulate the ejector inlet flow.

  15. Phased Acoustic Array Measurements of a 5.75 Percent Hybrid Wing Body Aircraft

    Science.gov (United States)

    Burnside, Nathan J.; Horne, William C.; Elmer, Kevin R.; Cheng, Rui; Brusniak, Leon

    2016-01-01

    Detailed acoustic measurements of the noise from the leading-edge Krueger flap of a 5.75 percent Hybrid Wing Body (HWB) aircraft model were recently acquired with a traversing phased microphone array in the AEDC NFAC (Arnold Engineering Development Complex, National Full Scale Aerodynamics Complex) 40- by 80-Foot Wind Tunnel at NASA Ames Research Center. The spatial resolution of the array was sufficient to distinguish between individual support brackets over the full-scale frequency range of 100 to 2875 Hertz. For conditions representative of landing and take-off configuration, the noise from the brackets dominated other sources near the leading edge. Inclusion of flight-like brackets for select conditions highlights the importance of including the correct number of leading-edge high-lift device brackets with sufficient scale and fidelity. These measurements will support the development of new predictive models.

  16. Aerodynamic performance of two fifteen-percent-scale wind-tunnel drive fan designs

    Science.gov (United States)

    Signor, D. B.; Borst, H. V.

    1986-01-01

    An experimental and analytical investigation of two fan blade designs was conducted. The fan blades tested were 15 percent scale models of the blades used in the National Full Scale Aerodynamic Complex fan drive at NASA Ames Research Center. The fan blades were composed of NACA-65 and modified NACA-65-series airfoil design sections. The blades with modified 65-series sections incorporated increased thickness on the upper surface, between the leading edge and the one-half chord position. Twist and taper were the same for both blade designs. The fan blades with modified 65-series sections were found to have an increase in stall margin when they were compared with the unmodified blades. The experimental performance data agreed favorably with theoretical calculations.

  17. A fuzzy neural network model to forecast the percent cloud coverage and cloud top temperature maps

    Directory of Open Access Journals (Sweden)

    Y. Tulunay

    2008-12-01

    Full Text Available Atmospheric processes are highly nonlinear. A small group at the METU in Ankara has been working on a fuzzy data driven generic model of nonlinear processes. The model developed is called the Middle East Technical University Fuzzy Neural Network Model (METU-FNN-M. The METU-FNN-M consists of a Fuzzy Inference System (METU-FIS, a data driven Neural Network module (METU-FNN of one hidden layer and several neurons, and a mapping module, which employs the Bezier Surface Mapping technique. In this paper, the percent cloud coverage (%CC and cloud top temperatures (CTT are forecast one month ahead of time at 96 grid locations. The probable influence of cosmic rays and sunspot numbers on cloudiness is considered by using the METU-FNN-M.

  18. Perennial snow and ice volumes on Iliamna Volcano, Alaska, estimated with ice radar and volume modeling

    Science.gov (United States)

    Trabant, Dennis C.

    1999-01-01

    The volume of four of the largest glaciers on Iliamna Volcano was estimated using the volume model developed for evaluating glacier volumes on Redoubt Volcano. The volume model is controlled by simulated valley cross sections that are constructed by fitting third-order polynomials to the shape of the valley walls exposed above the glacier surface. Critical cross sections were field checked by sounding with ice-penetrating radar during July 1998. The estimated volumes of perennial snow and glacier ice for Tuxedni, Lateral, Red, and Umbrella Glaciers are 8.6, 0.85, 4.7, and 0.60 cubic kilometers respectively. The estimated volume of snow and ice on the upper 1,000 meters of the volcano is about 1 cubic kilometer. The volume estimates are thought to have errors of no more than ?25 percent. The volumes estimated for the four largest glaciers are more than three times the total volume of snow and ice on Mount Rainier and about 82 times the total volume of snow and ice that was on Mount St. Helens before its May 18, 1980 eruption. Volcanoes mantled by substantial snow and ice covers have produced the largest and most catastrophic lahars and floods. Therefore, it is prudent to expect that, during an eruptive episode, flooding and lahars threaten all of the drainages heading on Iliamna Volcano. On the other hand, debris avalanches can happen any time. Fortunately, their influence is generally limited to the area within a few kilometers of the summit.

  19. 45 CFR 307.31 - Federal financial participation at the 80 percent rate for computerized support enforcement systems.

    Science.gov (United States)

    2010-10-01

    ... ENFORCEMENT SYSTEMS § 307.31 Federal financial participation at the 80 percent rate for computerized support... financial participation is available at the 80 percent rate to States, Territories and systems defined in 42... 45 Public Welfare 2 2010-10-01 2010-10-01 false Federal financial participation at the 80...

  20. 24 CFR 884.116 - Establishment of income limit schedules; 30 percent occupancy by very-low income families.

    Science.gov (United States)

    2010-04-01

    ... schedules; 30 percent occupancy by very-low income families. 884.116 Section 884.116 Housing and Urban... percent occupancy by very-low income families. (a) HUD will establish schedules of Income limits for determining whether families qualify as Low-Income Families and Very Low-Income Families. (b) In the...

  1. Personal Best Time, Percent Body Fat, and Training Are Differently Associated with Race Time for Male and Female Ironman Triathletes

    Science.gov (United States)

    Knechtle, Beat; Wirth, Andrea; Baumann, Barbara; Knechtle, Patrizia; Rosemann, Thomas

    2010-01-01

    We studied male and female nonprofessional Ironman triathletes to determine whether percent body fat, training, and/or previous race experience were associated with race performance. We used simple linear regression analysis, with total race time as the dependent variable, to investigate the relationship among athletes' percent body fat, average…

  2. 7 CFR 205.303 - Packaged products labeled “100 percent organic” or “organic.”

    Science.gov (United States)

    2010-01-01

    ... (CONTINUED) ORGANIC FOODS PRODUCTION ACT PROVISIONS NATIONAL ORGANIC PROGRAM Labels, Labeling, and Market Information § 205.303 Packaged products labeled “100 percent organic” or “organic.” (a) Agricultural products... product, the following: (1) The term, “100 percent organic” or “organic,” as applicable, to modify...

  3. The Use of Gas Chromatography and Mass Spectrometry to Introduce General Chemistry Students to Percent Mass and Atomic Mass Calculations

    Science.gov (United States)

    Pfennig, Brian W.; Schaefer, Amy K.

    2011-01-01

    A general chemistry laboratory experiment is described that introduces students to instrumental analysis using gas chromatography-mass spectrometry (GC-MS), while simultaneously reinforcing the concepts of mass percent and the calculation of atomic mass. Working in small groups, students use the GC to separate and quantify the percent composition…

  4. The Use of Gas Chromatography and Mass Spectrometry to Introduce General Chemistry Students to Percent Mass and Atomic Mass Calculations

    Science.gov (United States)

    Pfennig, Brian W.; Schaefer, Amy K.

    2011-01-01

    A general chemistry laboratory experiment is described that introduces students to instrumental analysis using gas chromatography-mass spectrometry (GC-MS), while simultaneously reinforcing the concepts of mass percent and the calculation of atomic mass. Working in small groups, students use the GC to separate and quantify the percent composition…

  5. Is percent seminoma associated with intraoperative morbidity during post-chemotherapy RPLND?

    Science.gov (United States)

    Russell, Christopher M; Sharma, Pranav; Agarwal, Gautum; Fisher, John S; Richard, George J; Spiess, Philippe E; Pow-Sang, Julio M; Poch, Michael A; Sexton, Wade J

    2016-02-01

    To evaluate whether varying degrees of seminomatous elements in the primary orchiectomy specimen would be predictive of patient morbidity during post-chemotherapy retroperitoneal lymph node dissection (PC-RPLND) since the desmoplastic reaction with seminoma is associated with increased intraoperative complexity. We retrospectively identified 127 patients who underwent PC-RPLND for residual retroperitoneal masses. Clinicodemographic, intraoperative, and 30 day postoperative outcomes were compared for patients with pure seminoma (SEM), mixed germ cell tumors (GCT) containing seminoma elements (NS+SEM), and tumors with no seminoma elements (NS). Multivariate logistic regression was used to determine independent predictors of intraoperative and postoperative 30 day complications. We excluded 19 patients who received chemotherapy prior to orchiectomy, 2 patients with primary extragonadal GCT, and 3 patients who underwent re-do RPLND, leaving 103 patients for analysis. Fourteen patients (13.6%) had SEM, 18 (17.5%) had NS+SEM, and 71 (68.9%) had only NS elements. SEM patients were older (p = 0.03), had more intraoperative blood loss (p = 0.03), and were more likely to have residual seminomatous components in their post-chemotherapy lymph node (LN) histology (p = 0.01). Percent seminoma in the orchiectomy specimen was an independent predictor of estimated blood loss > 1.5 liters (odds ratio: 1.04, 95% confidence interval: 1.01-1.07; p = 0.013) after adjusting for age, stage, IGCCC risk category, preop chemotherapy, number and largest LN removed, need for vascular or adjacent organ resection (including nephrectomy), and LN histology. Higher percentage of seminoma in the orchiectomy specimen is associated with increased estimated blood loss during PC-RPLND. Percent seminoma, therefore, may be a useful prognostic tool for appropriate pre-surgical planning prior to PC-RPLND.

  6. Effects of antiperspirant aluminum percent composition and mode of application on mock microcalcifications in mammography

    Energy Technology Data Exchange (ETDEWEB)

    Mesurolle, Benoît, E-mail: benoit.mesurolle@muhc.mcgill.ca; Ceccarelli, Joan; Karp, Igor; Sun, Simon; El-Khoury, Mona

    2014-02-15

    Objective: Active ingredients in antiperspirants – namely, aluminum-based complexes – can produce radiopaque particles on mammography, mimicking microcalcifications. The present study was designed to investigate whether the appearance of antiperspirant induced radiopaque particles observed on mammograms is dependent on the percentage of aluminum-based complexes in antiperspirants and/or on their mode of application. Methods: A total of 43 antiperspirants with aluminum-based complex percentages ranging between 16% and 25% were tested. Each antiperspirant was applied to a single use plastic shield and then placed on an ultrasound gel pad, simulating breast tissue. Two experiments were performed, comparing antiperspirants based on (1) their percentage of aluminum-based complexes (20 antiperspirants) and (2) their mode of applications (solid, gel, and roll-on) (26 antiperspirants). Two experienced, blinded radiologists read images produced in consensus and assessed the appearance of radiopaque particles based on their density and shape. Results: In experiment 1, there was no statistically significant association between the percent aluminum composition of invisible solid antiperspirants and the density or shape of the radiopaque particles (p-values > 0.05). In experiment 2, there was a statistically significant association between the shape of the radiopaque particles and the mode of application of the antiperspirant (p-value = 0.0015). Conclusions: Our study suggests that the mammographic appearance of the radiopaque antiperspirant particles is not related to their percent composition of aluminum complexes. However, their mode of application appears to influence the shape of radiopaque particles, solid antiperspirants mimicking microcalcifications the most and roll-on antiperspirants the least.

  7. Test of scintillating bars coupled to Silicon Photomultipliers for a charged particle tracking device

    CERN Document Server

    Cecchini, S; Esposti, L Degli; Lax, I; Mandrioli, G; Mauri, N; Pasqualini, L; Patrizii, L; Pozzato, M; Sirri, G; Tenti, M

    2016-01-01

    The results obtained in laboratory tests, using scintillator bars read by silicon photomultipliers are reported. The present approach is the first step for designing a precision tracking system to be placed inside a free magnetized volume for the charge identification of low energy crossing particles. The devised system is demonstrated able to provide a spatial resolution better than 2 mm.

  8. Integrated label-free silicon nanowire sensor arrays for (bio)chemical analysis

    NARCIS (Netherlands)

    De, Arpita; Nieuwkasteele, van Jan; Carlen, Edwin T.; Berg, van den Albert

    2013-01-01

    We present a label-free (bio)chemical analysis platform that uses all-electrical silicon nanowire sensor arrays integrated with a small volume microfluidic flow-cell for real-time (bio)chemical analysis and detection. The integrated sensing platform contains an automated multi-sample injection syste

  9. IC Compatible Wafer Level Fabrication of Silicon Nanowire Field Effect Transistors for Biosensing Applications

    NARCIS (Netherlands)

    Moh, T.S.Y.

    2013-01-01

    In biosensing, nano-devices such as Silicon Nanowire Field Effect Transistors (SiNW FETs) are promising components/sensors for ultra-high sensitive detection, especially when samples are low in concentration or a limited volume is available. Current processing of SiNW FETs often relies on expensive

  10. IC Compatible Wafer Level Fabrication of Silicon Nanowire Field Effect Transistors for Biosensing Applications

    NARCIS (Netherlands)

    Moh, T.S.Y.

    2013-01-01

    In biosensing, nano-devices such as Silicon Nanowire Field Effect Transistors (SiNW FETs) are promising components/sensors for ultra-high sensitive detection, especially when samples are low in concentration or a limited volume is available. Current processing of SiNW FETs often relies on expensive

  11. Silicon Tetrafluoride on Io

    CERN Document Server

    Schaefer, L; Schaefer, Laura

    2005-01-01

    Silicon tetrafluoride (SiF4) is observed in terrestrial volcanic gases and is predicted to be the major F - bearing species in low temperature volcanic gases on Io (Schaefer and Fegley, 2005b). SiF4 gas is also a potential indicator of silica-rich crust on Io. We used F/S ratios in terrestrial and extraterrestrial basalts, and gas/lava enrichment factors for F and S measured at terrestrial volcanoes to calculate equilibrium SiF4/SO2 ratios in volcanic gases on Io. We conclude that SiF4 can be produced at levels comparable to the observed NaCl/SO2 gas ratio. We also considered potential loss processes for SiF4 in volcanic plumes and in Io's atmosphere including ion-molecule reactions, electron chemistry, photochemistry, reactions with the major atmospheric constituents, and condensation. Photochemical destruction (tchem ~ 266 days) and/or condensation as Na2SiF6 (s) appear to be the major sinks for SiF4. We recommend searching for SiF4 with infrared spectroscopy using its 9.7 micron band as done on Earth.

  12. Collimation: a silicon solution

    CERN Multimedia

    2007-01-01

    Silicon crystals could be used very efficiently to deflect high-energy beams. Testing at CERN has produced conclusive results, which could pave the way for a new generation of collimators. The set of five crystals used to test the reflection of the beams. The crystals are 0.75 mm wide and their alignment is adjusted with extreme precision. This figure shows the deflection of a beam by channelling and by reflection in the block of five crystals. Depending on the orientation of the crystals: 1) The beam passes without "seeing" the crystals and is not deflected 2) The beam is deflected by channelling (with an angle of around 100 μrad) 3) The beam is reflected (with an angle of around 50 μrad). The intensity of the deflected beam is illustrated by the intensity of the spot. The spot of the reflected beam is clearly more intense than that one of the channelled beam, demonstrating the efficiency of t...

  13. Nanoporous silicon oxide memory.

    Science.gov (United States)

    Wang, Gunuk; Yang, Yang; Lee, Jae-Hwang; Abramova, Vera; Fei, Huilong; Ruan, Gedeng; Thomas, Edwin L; Tour, James M

    2014-08-13

    Oxide-based two-terminal resistive random access memory (RRAM) is considered one of the most promising candidates for next-generation nonvolatile memory. We introduce here a new RRAM memory structure employing a nanoporous (NP) silicon oxide (SiOx) material which enables unipolar switching through its internal vertical nanogap. Through the control of the stochastic filament formation at low voltage, the NP SiOx memory exhibited an extremely low electroforming voltage (∼ 1.6 V) and outstanding performance metrics. These include multibit storage ability (up to 9-bits), a high ON-OFF ratio (up to 10(7) A), a long high-temperature lifetime (≥ 10(4) s at 100 °C), excellent cycling endurance (≥ 10(5)), sub-50 ns switching speeds, and low power consumption (∼ 6 × 10(-5) W/bit). Also provided is the room temperature processability for versatile fabrication without any compliance current being needed during electroforming or switching operations. Taken together, these metrics in NP SiOx RRAM provide a route toward easily accessed nonvolatile memory applications.

  14. Preparation and dielectric properties of porous silicon nitride ceramics

    Institute of Scientific and Technical Information of China (English)

    LI Jun-qi; LUO Fa; ZHU Dong-mei; ZHOU Wan-cheng

    2006-01-01

    Porous silicon nitride ceramics with difference volume fractions of porosity from 34.1% to 59.2% were produced by adding different amount of the pore-forming agent into initial silicon nitride powder. The microwave dielectric property of these ceramics at a frequency of 9.36 GHz was studied. The crystalline phases of the samples were determined by X-ray diffraction analysis. The influence of porosity on the dielectric properties was evaluated. The results show that α-Si3N4 crystalline phase exists in all the samples while the main crystalline phase of the samples is β-Si3N4,indicating that the a/b transformation happens during the preparation of samples and the transformation is incomplete. There is a dense matrix containing large pores and cavities with needle-shaped and flaky β-Si3N4 grains distributing. The dielectric constant of the ceramics reduces with the increase of porosity.

  15. Performance of the CLAS12 Silicon Vertex Tracker modules

    Energy Technology Data Exchange (ETDEWEB)

    Antonioli, Mary Ann [JLAB; Boiarinov, Serguie; Bonneau, Peter R. [JLAB; Elouadrhiri, Latifa [JLAB; Eng, Brian J. [JLAB; Gotra, Yuri N. [JLAB; Kurbatov, Evgeny O. [Moscow State U.; Leffel, Mindy A. [JLAB; Mandal, Saptarshi [JLAB; McMullen, Marc E. [JLAB; Merkin, Mikhail M. [Moscow State U.; Raydo, Benjamin J. [JLAB; Teachey, Robert W, [JLAB; Tucker, Ross J. [Arizona State U.; Ungaro, Maurizio [JLAB; Yegneswaran, Amrit S. [JLAB; Ziegler, Veronique [JLAB

    2013-12-01

    For the 12 GeV upgrade, the CLAS12 experiment has designed a Silicon Vertex Tracker (SVT) using single sided microstrip sensors fabricated by Hamamatsu. The sensors have graded angle design to minimize dead areas and a readout pitch of 156{micro}m, with intermediate strip. Double sided SVT module hosts three daisy-chained sensors on each side with a full strip length of 33 cm. There are 512 channels per module read out by four Fermilab Silicon Strip Readout (FSSR2) chips featuring data driven architecture, mounted on a rigid-flex hybrid. Modules are assembled on the barrel using unique cantilevered geometry to minimize the amount of material in the tracking volume. Design and performance of the SVT modules are presented, focusing on results of electrical measurements.

  16. New methodology for through silicon via array macroinspection

    Science.gov (United States)

    Fujimori, Yoshihiko; Tsuto, Takashi; Kudo, Yuji; Inoue, Takeshi; Suwa, Kyoichi; Okamoto, Kazuya

    2013-01-01

    A new methodology for inspection of through silicon via (TSV) process wafers is developed by utilizing an optical diffraction signal from the wafers. The optical system uses telecentric illumination and has a two-dimensional sensor for capturing the diffracted light from TSV arrays. The diffraction signal modulates the intensity of the wafer image. The optical configuration is optimized for TSV array inspection. The diffraction signal is sensitive to via-shape variations, and an area of deviation from a nominal via is analyzed using the signal. Using test wafers with deep via patterns on silicon wafers, the performance is evaluated and the sensitivities for various pattern profile changes are confirmed. This new methodology is available for high-volume manufacturing of future TSV three-dimensional complementary metal oxide semiconductor devices.

  17. Optical thermometry based on level anticrossing in silicon carbide.

    Science.gov (United States)

    Anisimov, A N; Simin, D; Soltamov, V A; Lebedev, S P; Baranov, P G; Astakhov, G V; Dyakonov, V

    2016-09-14

    We report a giant thermal shift of 2.1 MHz/K related to the excited-state zero-field splitting in the silicon vacancy centers in 4H silicon carbide. It is obtained from the indirect observation of the optically detected magnetic resonance in the excited state using the ground state as an ancilla. Alternatively, relative variations of the zero-field splitting for small temperature differences can be detected without application of radiofrequency fields, by simply monitoring the photoluminescence intensity in the vicinity of the level anticrossing. This effect results in an all-optical thermometry technique with temperature sensitivity of 100 mK/Hz(1/2) for a detection volume of approximately 10(-6) mm(3). In contrast, the zero-field splitting in the ground state does not reveal detectable temperature shift. Using these properties, an integrated magnetic field and temperature sensor can be implemented on the same center.

  18. Chemical surface management for micro PCR in silicon chip thermocyclers

    Science.gov (United States)

    Felbel, Jana; Bieber, Ivonne; Koehler, Johann M.

    2002-11-01

    Silicon, silicon dioxide, glass and other key materials of micro system technology show an inhibiting effect on PCR. This negative influence becomes seriously, if devices are miniaturized, particularly in case of flow-through devices due to their high surface to volume ratio. In contrast, alkyl-substituted surfaces do not inhibit the reaction. Although the silanization improves the compatibility, the suppression of inhibition by wall surface treatment was not stable over longer time intervals. Therefore, the stability of chemical surface modifications was studied in dependence of silanization, material, pH, temperature and buffer composition. The efficiency of surface covering by molecular substitution was characterized by wetting experiments as well as by PCR test runs. The results show that the surface treatment can be optimized by the choice of silanization agents and the concentration of surface active additives.

  19. Planar Edgeless Silicon Detectors for the TOTEM Experiment

    CERN Document Server

    Ruggiero, G; Deile, M; De Oliveira, R; Eggert, K; Haug, F; Jarron, P; Macina, D; Niewiadomski, H; Noschis, E; Oriunno, M; Siegrist, P; Snoeys, W; Verdier, A; Avati, V; Bergholm, V; Kalliopuska, J; Kiiskinen, A P; Kurvinen, K; Lauhakangas, R; Mäki, T; Oljemark, F; Orava, R; Österberg, K; Palmieri, V G; Saarikko, H; Tapprogge, S; Toppinen, A; Bassetti, V; Boccone, V; Bozzo, M; Buzzo, A; Cereseto, R; Cuneo, S; Ferro, F; Macri, M; Minutoli, S; Morelli, A; Musico, P; Negri, M; Puppo, R; Santroni, A; Sette, G; Berardi, V; Catanesi, M G; Radicioni, E; Egorov, N; Sidorov, A; Eremin, I; Hasi, J; Kok, A; Watts, S; Herzog, R; Rudischer, R; Wobst, E; Kundrát, W; Lokajícek, M; Smotlacha, J; Sanguinetti, G; Mirabito, L

    2005-01-01

    Silicon detectors for the Roman Pots of the large hadron collider TOTEM experiment aim for full sensitivity at the edge where a terminating structure is required for electrical stability. This work provides an innovative approach reducing the conventional width of the terminating structure to less than 100 microns, still using standard planar fabrication technology. The objective of this new development is to decouple the electric behaviour of the surface from the sensitive volume within tens of microns. The explanation of the basic principle of this new approach together with the experimental confirmation via electric measurements and beam test are presented in this paper, demonstrating that silicon detectors with this new terminating structure are fully operational and efficient to under 60 microns from the die cut.

  20. Limits on light emission from silicon Invited Paper

    Institute of Scientific and Technical Information of China (English)

    Peter Würfel

    2009-01-01

    Although silicon is an indirect semiconductor, light emission from silicon is governed by the same gener-alized Planck's radiation law as the emission from direct semiconductors. The emission intensity is given by the absorptance of the volume in which there is a difference of the quasi Fermi energies. A difference of the Fermi energies may rcsult from the absorption of external light (photoluminescence) or from the in-jection of electrons and holes via selective contacts (electroluminescence). The quantum efficiency may be larger than 0.5 for carrier densities below 1015 cm-3. At larger densities, non-radiative recombination, in particular Auger recombination dominates. At all carrier densities, the relation between emission intensity and difference of the quasi Fermi energies is maintained. Since this difference is equal to the voltage of a properly designed solar cell, luminescence is the key indicator of material quality for solar cells.

  1. Optical thermometry based on level anticrossing in silicon carbide

    Science.gov (United States)

    Anisimov, A. N.; Simin, D.; Soltamov, V. A.; Lebedev, S. P.; Baranov, P. G.; Astakhov, G. V.; Dyakonov, V.

    2016-09-01

    We report a giant thermal shift of 2.1 MHz/K related to the excited-state zero-field splitting in the silicon vacancy centers in 4H silicon carbide. It is obtained from the indirect observation of the optically detected magnetic resonance in the excited state using the ground state as an ancilla. Alternatively, relative variations of the zero-field splitting for small temperature differences can be detected without application of radiofrequency fields, by simply monitoring the photoluminescence intensity in the vicinity of the level anticrossing. This effect results in an all-optical thermometry technique with temperature sensitivity of 100 mK/Hz1/2 for a detection volume of approximately 10-6 mm3. In contrast, the zero-field splitting in the ground state does not reveal detectable temperature shift. Using these properties, an integrated magnetic field and temperature sensor can be implemented on the same center.

  2. Ultrafast Terahertz Conductivity of Photoexcited Nanocrystalline Silicon

    DEFF Research Database (Denmark)

    Cooke, David; MacDonald, A. Nicole; Hryciw, Aaron;

    2007-01-01

    The ultrafast transient ac conductivity of nanocrystalline silicon films is investigated using time-resolved terahertz spectroscopy. While epitaxial silicon on sapphire exhibits a free carrier Drude response, silicon nanocrystals embedded in glass show a response that is best described by a class......The ultrafast transient ac conductivity of nanocrystalline silicon films is investigated using time-resolved terahertz spectroscopy. While epitaxial silicon on sapphire exhibits a free carrier Drude response, silicon nanocrystals embedded in glass show a response that is best described...

  3. Next generation structural silicone glazing

    Directory of Open Access Journals (Sweden)

    Charles D. Clift

    2015-06-01

    Full Text Available This paper presents an advanced engineering evaluation, using nonlinear analysis of hyper elastic material that provides significant improvement to structural silicone glazing (SSG design in high performance curtain wall systems. Very high cladding wind pressures required in hurricane zones often result in bulky SSG profile dimensions. Architectural desire for aesthetically slender curtain wall framing sight-lines in combination with a desire to reduce aluminium usage led to optimization of silicone material geometry for better stress distribution.To accomplish accurate simulation of predicted behaviour under structural load, robust stress-strain curves of the silicone material are essential. The silicone manufacturer provided physical property testing via a specialized laboratory protocol. A series of rigorous curve fit techniques were then made to closely model test data in the finite element computer analysis that accounts for nonlinear strain of hyper elastic silicone.Comparison of this advanced design technique to traditional SSG design highlights differences in stress distribution contours in the silicone material. Simplified structural engineering per the traditional SSG design method does not provide accurate forecasting of material and stress optimization as shown in the advanced design.Full-scale specimens subject to structural load testing were performed to verify the design capacity, not only for high wind pressure values, but also for debris impact per ASTM E1886 and ASTM E1996. Also, construction of the test specimens allowed development of SSG installation techniques necessitated by the unique geometry of the silicone profile. Finally, correlation of physical test results with theoretical simulations is made, so evaluation of design confidence is possible. This design technique will introduce significant engineering advancement to the curtain wall industry.

  4. Palladium interaction with silicon carbide

    Energy Technology Data Exchange (ETDEWEB)

    Gentile, M., E-mail: Marialuisa.Gentile@manchester.ac.uk [Centre for Nuclear Energy Technology (C-NET), School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Manchester M13 9PL (United Kingdom); Xiao, P. [Materials Science Centre, School of Materials, The University of Manchester, Manchester M13 9PL (United Kingdom); Abram, T. [Centre for Nuclear Energy Technology (C-NET), School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Manchester M13 9PL (United Kingdom)

    2015-07-15

    In this work the palladium interaction with silicon carbide is investigated by means of complementary analytical techniques such as thermogravimetry (TG), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Thermoscans were carried out on pellets of palladium, α-SiC and β-SiC high purity powders in the temperature range comprised between 293 K and 1773 K, in order to study the effect of temperature on the palladium-silicon carbide reaction. Thermoscans of α-SiC pellets containing 5 at.%Pd show that during differential calorimetry scans three exothermic peaks occurred at 773 K, 1144 K and 1615 K, while thermoscans of β-SiC pellets containing 3 at.%Pd and 5 at.%Pd do not show peaks. For the pellet α-SiC–5 at.%Pd XRD spectra reveal that the first peak is associated with the formation of Pd{sub 3}Si and SiO{sub 2} phases, while the second peak and the third peak are correlated with the formation of Pd{sub 2}Si phase and the active oxidation of silicon carbide respectively. Thermogravimetry scans show weight gain and weight loss peaks due to the SiO{sub 2} phase formation and the active oxidation. Additionally XPS fittings reveal the development of SiC{sub x}O{sub y} phase during the first exothermic peak up to the temperature of 873 K. The experimental data reveals that alpha silicon carbide is attacked by palladium at lower temperatures than beta silicon carbide and the reaction mechanism between silicon carbide and palladium is strongly affected by silicon carbide oxidation.

  5. Palladium interaction with silicon carbide

    Science.gov (United States)

    Gentile, M.; Xiao, P.; Abram, T.

    2015-07-01

    In this work the palladium interaction with silicon carbide is investigated by means of complementary analytical techniques such as thermogravimetry (TG), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Thermoscans were carried out on pellets of palladium, α-SiC and β-SiC high purity powders in the temperature range comprised between 293 K and 1773 K, in order to study the effect of temperature on the palladium-silicon carbide reaction. Thermoscans of α-SiC pellets containing 5 at.%Pd show that during differential calorimetry scans three exothermic peaks occurred at 773 K, 1144 K and 1615 K, while thermoscans of β-SiC pellets containing 3 at.%Pd and 5 at.%Pd do not show peaks. For the pellet α-SiC-5 at.%Pd XRD spectra reveal that the first peak is associated with the formation of Pd3Si and SiO2 phases, while the second peak and the third peak are correlated with the formation of Pd2Si phase and the active oxidation of silicon carbide respectively. Thermogravimetry scans show weight gain and weight loss peaks due to the SiO2 phase formation and the active oxidation. Additionally XPS fittings reveal the development of SiCxOy phase during the first exothermic peak up to the temperature of 873 K. The experimental data reveals that alpha silicon carbide is attacked by palladium at lower temperatures than beta silicon carbide and the reaction mechanism between silicon carbide and palladium is strongly affected by silicon carbide oxidation.

  6. III-V semiconductor devices integrated with silicon III-V semiconductor devices integrated with silicon

    Science.gov (United States)

    Hopkinson, Mark; Martin, Trevor; Smowton, Peter

    2013-09-01

    The integration of III-V semiconductor devices with silicon is one of the most topical challenges in current electronic materials research. The combination has the potential to exploit the unique optical and electronic functionality of III-V technology with the signal processing capabilities and advanced low-cost volume production techniques associated with silicon. Key industrial drivers include the use of high mobility III-V channel materials (InGaAs, InAs, InSb) to extend the performance of Si CMOS, the unification of electronics and photonics by combining photonic components (GaAs, InP) with a silicon platform for next-generation optical interconnects and the exploitation of large-area silicon substrates and high-volume Si processing capabilities to meet the challenges of low-cost production, a challenge which is particularly important for GaN-based devices in both power management and lighting applications. The diverse nature of the III-V and Si device approaches, materials technologies and the distinct differences between industrial Si and III-V processing have provided a major barrier to integration in the past. However, advances over the last decade in areas such as die transfer, wafer fusion and epitaxial growth have promoted widespread renewed interest. It is now timely to bring some of these topics together in a special issue covering a range of approaches and materials providing a snapshot of recent progress across the field. The issue opens a paper describing a strategy for the epitaxial integration of photonic devices where Kataria et al describe progress in the lateral overgrowth of InP/Si. As an alternative, Benjoucef and Reithmaier report on the potential of InAs quantum dots grown direct onto Si surfaces whilst Sandall et al describe the properties of similar InAs quantum dots as an optical modulator device. As an alternative to epitaxial integration approaches, Yokoyama et al describe a wafer bonding approach using a buried oxide concept, Corbett

  7. Spray drying method for large-scale and high-performance silicon negative electrodes in Li-ion batteries.

    Science.gov (United States)

    Jung, Dae Soo; Hwang, Tae Hoon; Park, Seung Bin; Choi, Jang Wook

    2013-05-08

    Nanostructured silicon electrodes have shown great potential as lithium ion battery anodes because they can address capacity fading mechanisms originating from large volume changes of silicon alloys while delivering extraordinarily large gravimetric capacities. Nonetheless, synthesis of well-defined silicon nanostructures in an industrially adaptable scale still remains as a challenge. Herein, we adopt an industrially established spray drying process to enable scalable synthesis of silicon-carbon composite particles in which silicon nanoparticles are embedded in porous carbon particles. The void space existing in the porous carbon accommodates the volume expansion of silicon and thus addresses the chronic fading mechanisms of silicon anodes. The composite electrodes exhibit excellent electrochemical performance, such as 1956 mAh/g at 0.05C rate and 91% capacity retention after 150 cycles. Moreover, the spray drying method requires only 2 s for the formation of each particle and allows a production capability of ~10 g/h even with an ultrasonic-based lab-scale equipment. This investigation suggests that established industrial processes could be adaptable to the production of battery active materials that require sophisticated nanostructures as well as large quantity syntheses.

  8. Quality assurance of double-sided silicon microstrip sensors for the silicon tracking system in the CBM experiment at FAIR

    Energy Technology Data Exchange (ETDEWEB)

    Larionov, Pavel [Goethe Universitaet, Frankfurt (Germany); Collaboration: CBM-Collaboration

    2015-07-01

    The Silicon Tracking System (STS) is the core tracking detector of the CBM experiment at FAIR. The system's task is to reconstruct the trajectories of the charged particles produced in the beam-target interactions, provide their momentum determination, and enable the detection of decay topologies. The STS will comprise 1220 double-sided silicon microstrip sensors. After production each sensor will go through a number of Quality Assurance procedures to verify their validity for performance in the STS and also to confirm the manufacturer's data. In this talk, results of the quality assurance procedures that are being applied to the latest STS prototype sensors, including detailed tests of the quality of each single strip, long-term stability and preparations for volume tests during series production, are presented.

  9. Electrical properties of laser-bonded Silicon-On-Diamond samples

    Energy Technology Data Exchange (ETDEWEB)

    Sciortino, S., E-mail: silvio.sciortino@gmail.com [National Institute for Nuclear Physics, INFN, Florence (Italy); Department of Physics and Astronomy, University of Florence (Italy); Brandi, F.; Carzino, R. [Nanophysics, Istituto Italiano di Tecnologia, Genova (Italy); Citroni, M. [European Laboratory for Non-Linear Spectroscopy, LENS, Florence (Italy); De Sio, A. [Department of Physics and Astronomy, University of Florence (Italy); Fanetti, S. [European Laboratory for Non-Linear Spectroscopy, LENS, Florence (Italy); Lagomarsino, S. [National Institute for Nuclear Physics, INFN, Florence (Italy); Department of Physics and Astronomy, University of Florence (Italy); Pace, E. [Department of Physics and Astronomy, University of Florence (Italy); Parrini, G. [National Institute for Nuclear Physics, INFN, Florence (Italy); Department of Physics and Astronomy, University of Florence (Italy); Passeri, D.; Scorzoni, A.; Servoli, L. [Dipartimento di Ingegneria Elettronica e della Informazione and INFN Sez. Perugia, Perugia (Italy); Tozzetti, L. [Department of Physics and Astronomy, University of Florence (Italy)

    2013-12-01

    In this work we report preliminary tests aimed at the implementation of a Silicon-On-Diamond (SOD) radiation sensor. SOD materials have been prepared by continuously scanning a 20 ps pulsed 355 nm laser beam on the silicon–diamond interface. A pixel monolithic sensor has also been bonded to diamond with the same technique and tested to show that a complex electronic chip can undergo the process without any damage. Through silicon vias have been fabricated by laser drilling on the silicon side of the SOD samples and their insulation from the silicon bulk has been tested. The charge collection efficiency of a diamond sensor with laser-written graphitic contacts has been measured, to demonstrate a reliable and simple way to fabricate ohmic contacts on the diamond side of the SOD devices. Finally, a SOD material with electric contacts on the silicon and on the diamond sides has been tested as a particle sensor to demonstrate the electrical continuity of the silicon–diamond interface after the bonding. -- Highlights: •The steps necessary to fabricate a monolithic Silicon-On-Diamond detector have been carried out. •These steps involve the bonding, by a laser technique, of an electronic chip on diamond without damage, the growth of insulated Through Silicon Vias in silicon, the fabrication of ohmic contacts by laser graphitization. •In conclusion: the feasibility of a SOD detector with the readout silicon electronics bonded to the diamond sensitive volume has been demonstrated. •Graphitic contacts compare favorably with standard metallic ones. •Charge is collected by a SOD material. That is, the silicon–diamond bonding interface does not prevent charge collection.

  10. DEPTH MEASUREMENT OF DISRUPTED LAYER ON SILICON WAFER SURFACE USING AUGER SPECTROSCOPY METHOD

    Directory of Open Access Journals (Sweden)

    V. A. Solodukha

    2016-01-01

    Full Text Available The paper proposes a method for depth measurement of a disrupted layer on silicon wafer surface which is based on application of Auger spectroscopy with the precision sputtering of surface silicon layers and registration of the Auger electron yield intensity. In order to measure the disrupted layer with the help of Auger spectroscopy it is necessary to determine dependence of the released Auger electron amount on sputtering time (profile and then the dependence is analyzed. Silicon amount in the disrupted layer is less than in the volume. While going deeper the disruptive layer is decreasing that corresponds to an increase of atom density in a single layer. The essence of the method lies in the fact the disruptive layer is removed by ion beam sputtering and detection of interface region is carried out with the help of registration of the Auger electron yield intensity from the sputtered surface up to the moment when it reaches the value which is equal to the Auger electron yield intensity for single-crystal silicon. While removing surface silicon layers the registration of the Auger electron yield intensity from silicon surface makes it possible to control efficiently a presence of the disrupted layer on the silicon wafer surface. In this case depth control locality is about 1.0 nm due to some peculiarities of Auger spectroscopy method. The Auger electron yield intensity is determined automatically while using Auger spectrometer and while removing the disrupted layer the intensity is gradually increasing. Depth of the disrupted layer is determined by measuring height of the step which has been formed as a result of removal of the disrupted layer from the silicon wafer surface. Auger spectroscopy methods ensures an efficient depth control surface disruptions at the manufacturing stages of silicon wafers and integrated circuits. The depth measurement range of disruptions constitutes 0.001–1.000 um.

  11. Indentation fatigue in silicon nitride, alumina and silicon carbide ceramics

    Indian Academy of Sciences (India)

    A K Mukhopadhyay

    2001-04-01

    Repeated indentation fatigue (RIF) experiments conducted on the same spot of different structural ceramics viz. a hot pressed silicon nitride (HPSN), sintered alumina of two different grain sizes viz. 1 m and 25 m, and a sintered silicon carbide (SSiC) are reported. The RIF experiments were conducted using a Vicker’s microhardness tester at various loads in the range 1–20 N. Subsequently, the gradual evolution of the damage was characterized using an optical microscope in conjunction with the image analysing technique. The materials were classified in the order of the decreasing resistance against repeated indentation fatigue at the highest applied load of 20 N. It was further shown that there was a strong influence of grain size on the development of resistance against repeated indentation fatigue on the same spot. Finally, the poor performance of the sintered silicon carbide was found out to be linked to its previous thermal history.

  12. Silicon-to-silicon wafer bonding using evaporated glass

    DEFF Research Database (Denmark)

    Weichel, Steen; Reus, Roger De; Lindahl, M.

    1998-01-01

    Anodic bending of silicon to silicon 4-in. wafers using an electron-beam evaporated glass (Schott 8329) was performed successfully in air at temperatures ranging from 200 degrees C to 450 degrees C. The composition of the deposited glass is enriched in sodium as compared to the target material....... The roughness of the as-deposited films was below 5 nm and was found to be unchanged by annealing at 500 degrees C for 1 h in air. No change in the macroscopic edge profiles of the glass film was found as a function of annealing; however, small extrusions appear when annealing above 450 degrees C. Annealing...... of silicon/glass structures in air around 340 degrees C for 15 min leads to stress-free structures. Bonded wafer pairs, however, show no reduction in stress and always exhibit compressive stress. The bond yield is larger than 95% for bonding temperatures around 350 degrees C and is above 80% for bonding...

  13. Poppet valve control of throat stability bypass to increase stable airflow range of a Mach 2.5. inlet with 60 percent internal contraction

    Science.gov (United States)

    Mitchell, G. A.; Sanders, B. W.

    1975-01-01

    The throat of a Mach 2.5 inlet with a coldpipe termination was fitted with a stability-bypass system. System variations included several stability bypass entrance configurations. Poppet valves controlled the bypass airflow. The inlet stable airflow range achieved with each configuration was determined for both steady state conditions and internal pulse transients. Results are compared with those obtained without a stability bypass system. Transient results were also obtained for the inlet with a choke point at the diffuser exit and for the inlet with large and small stability bypass plenum volumes. Poppet valves at the stability bypass exit provided the inlet with a stable airflow range of 20 percent or greater at all static and transient conditions.

  14. Development of thin wraparound junction silicon solar cells

    Science.gov (United States)

    Ho, F.; Iles, P. A.

    1981-01-01

    The state of the art technologies was applied to fabricate 50 micro thick 2x4 cm, coplanar back contact (CBC) solar cells with AMO efficiency above 12%. A requirement was that the cells have low solar absorptance. A wraparound junction (WAJ) with wraparound metallization was chosen. This WAJ approach avoided the need for very complex fixturing, especially during rotation of the cells for providing adequate contacts over dielectric edge layers. The contact adhesion to silicon was considered better than to an insulator. It is indicated that shunt resistance caused by poor WAJ diode quality, and series resistance from the WAJ contact, give good cell performance. The cells developed reached 14 percent AMO efficiency (at 25 C), with solar absorptance values of 0.73. Space/cell environmental tests were performed on these cells and the thin CSC cells performed well. The optimized design configuration and process sequence were used to make 50 deliverable CBC cells. These cells were all above 12 percent efficiency and had an average efficiency of -13 percent. Results of environmental tests (humidity-temperature, thermal shock, and contact adherence) are also given.

  15. Silicon-micromachined microchannel plates

    Energy Technology Data Exchange (ETDEWEB)

    Beetz, Charles P. E-mail: NanoSystem@aol.com; Boerstler, Robert; Steinbeck, John; Lemieux, Bryan; Winn, David R. E-mail: winn@fair1.fairfield.edu

    2000-03-11

    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 {approx}0.5 to {approx}25 {mu}m, 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 deg. C, also compatible with high-temperature 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.

  16. Silicon-micromachined microchannel plates

    Science.gov (United States)

    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.

  17. Silicon nitride equation of state

    Science.gov (United States)

    Brown, Robert C.; Swaminathan, Pazhayannur K.

    2017-01-01

    This report presents the development of a global, multi-phase equation of state (EOS) for the ceramic silicon nitride (Si3N4).1 Structural forms include amorphous silicon nitride normally used as a thin film and three crystalline polymorphs. Crystalline phases include hexagonal α-Si3N4, hexagonal β-Si3N4, and the cubic spinel c-Si3N4. Decomposition at about 1900 °C results in a liquid silicon phase and gas phase products such as molecular nitrogen, atomic nitrogen, and atomic silicon. The silicon nitride EOS was developed using EOSPro which is a new and extended version of the PANDA II code. Both codes are valuable tools and have been used successfully for a variety of material classes. Both PANDA II and EOSPro can generate a tabular EOS that can be used in conjunction with hydrocodes. The paper describes the development efforts for the component solid phases and presents results obtained using the EOSPro phase transition model to investigate the solid-solid phase transitions in relation to the available shock data that have indicated a complex and slow time dependent phase change to the c-Si3N4 phase. Furthermore, the EOSPro mixture model is used to develop a model for the decomposition products; however, the need for a kinetic approach is suggested to combine with the single component solid models to simulate and further investigate the global phase coexistences.

  18. Immigrants in the one percent: The national origin of top wealth owners

    Science.gov (United States)

    Keister, Lisa A.; Aronson, Brian

    2017-01-01

    Background Economic inequality in the United States is extreme, but little is known about the national origin of affluent households. Households in the top one percent by total wealth own vastly disproportionate quantities of household assets and have correspondingly high levels of economic, social, and political influence. The overrepresentation of white natives (i.e., those born in the U.S.) among high-wealth households is well-documented, but changing migration dynamics suggest that a growing portion of top households may be immigrants. Methods Because no single survey dataset contains top wealth holders and data about country of origin, this paper uses two publicly-available data sets: the Survey of Consumer Finances (SCF) and the Survey of Income and Program Participation (SIPP). Multiple imputation is used to impute country of birth from the SIPP into the SCF. Descriptive statistics are used to demonstrate reliability of the method, to estimate the prevalence of immigrants among top wealth holders, and to document patterns of asset ownership among affluent immigrants. Results Significant numbers of top wealth holders who are usually classified as white natives may be immigrants. Many top wealth holders appear to be European and Canadian immigrants, and increasing numbers of top wealth holders are likely from Asia and Latin America as well. Results suggest that of those in the top one percent of wealth holders, approximately 3% are European and Canadian immigrants, .5% are from Mexico or Cuban, and 1.7% are from Asia (especially Hong Kong, Taiwan, Mainland China, and India). Ownership of key assets varies considerably across affluent immigrant groups. Conclusion Although the percentage of top wealth holders who are immigrants is relatively small, these percentages represent large numbers of households with considerable resources and corresponding social and political influence. Evidence that the propensity to allocate wealth to real and financial assets varies

  19. Compositional analysis of silicon

    Science.gov (United States)

    Kazmerski, L. L.

    1985-05-01

    The use of surface analysis methods in the detection and evaluation of elemental and impurity species in Si is presented. Examples are provided from polycrystalline Si and high-efficiency MINP cells. Auger electron spectroscopy and secondary ion mass spectrometry are used to complement microelectrical data obtained by electron-beam induced-current measurements. A new method is discussed which utilizes the volume indexing of digital secondary ion mass spectroscopy signals, providing compositional information and impurity maps on internal materials/device interfaces.

  20. Determination of fiber volume in graphite/epoxy materials using computer image analysis

    Science.gov (United States)

    Viens, Michael J.

    1990-01-01

    The fiber volume of graphite/epoxy specimens was determined by analyzing optical images of cross sectioned specimens using image analysis software. Test specimens were mounted and polished using standard metallographic techniques and examined at 1000 times magnification. Fiber volume determined using the optical imaging agreed well with values determined using the standard acid digestion technique. The results were found to agree within 5 percent over a fiber volume range of 45 to 70 percent. The error observed is believed to arise from fiber volume variations within the graphite/epoxy panels themselves. The determination of ply orientation using image analysis techniques is also addressed.