WorldWideScience

Sample records for junction fabrication process

  1. Double-side fabrication process and millimeter wave response of intrinsic Josephson junctions

    Institute of Scientific and Technical Information of China (English)

    WU JingBo; YI DongChao; GU ZhengHao; KANG Lin; XU WeiWei; CHEN Jian; WU PeiHeng

    2009-01-01

    We adopted double-side fabrication process to prepare intrinsic Josephson junctions (IJJs) based on Bi2Sr2CaCu2O8-x(BSCCO) single crystals. Using crystal cleavage and double-side argon ion milling, we have successfully fabricated very uniform IJJs with the thickness of single crystal slice less than 200 nm. Using quasi-optical system, the response of the IJJs to millimeter wave radiation was studied. With applied magnetic field perpendicular to a-b plane, we have observed Shapiro steps under millimeter wave radiation, and the Josephson oscillation of each junction was phase-locking.

  2. Tunnel Field-Effect Transistor with Epitaxially Grown Tunnel Junction Fabricated by Source/Drain-First and Tunnel-Junction-Last Processes

    Science.gov (United States)

    Morita, Yukinori; Mori, Takahiro; Migita, Shinji; Mizubayashi, Wataru; Tanabe, Akihito; Fukuda, Koichi; Masahara, Meishoku; Ota, Hiroyuki

    2013-04-01

    We fabricate p- and n-channel Si tunnel field-effect transistors (TFETs) with an epitaxially grown tunnel junction. In a novel source/drain-first and tunnel-junction-last fabrication process, a thin epitaxial undoped Si channel (epichannel) is deposited on a preferentially fabricated p- or n-type source area. The epichannel sandwiched by a gate insulator and a highly doped source well acts as a parallel-plate tunnel capacitor, which effectively multiplies drain current with an enlarged tunnel area. On the basis of its simple structure and easy fabrication, symmetric n- and p-transistor and complementary metal oxide semiconductor inverter operations were successfully demonstrated.

  3. Anodization-based process for the fabrication of all niobium nitride Josephson junction structures

    Directory of Open Access Journals (Sweden)

    Massimiliano Lucci

    2017-03-01

    Full Text Available We studied the growth and oxidation of niobium nitride (NbN films that we used to fabricate superconductive tunnel junctions. The thin films were deposited by dc reactive magnetron sputtering using a mixture of argon and nitrogen. The process parameters were optimized by monitoring the plasma with an optical spectroscopy technique. This technique allowed us to obtain NbN as well as good quality AlN films and both were used to obtain NbN/AlN/NbN trilayers. Lift-off lithography and selective anodization of the NbN films were used, respectively, to define the main trilayer geometry and/or to separate electrically, different areas of the trilayers. The anodized films were characterized by using Auger spectroscopy to analyze compounds formed on the surface and by means of a nano-indenter in order to investigate its mechanical and adhesion properties. The transport properties of NbN/AlN/NbN Josephson junctions obtained as a result of the above described fabrication process were measured in liquid helium at 4.2 K.

  4. Semiconductor device PN junction fabrication using optical processing of amorphous semiconductor material

    Science.gov (United States)

    Sopori, Bhushan; Rangappan, Anikara

    2014-11-25

    Systems and methods for semiconductor device PN junction fabrication are provided. In one embodiment, a method for fabricating an electrical device having a P-N junction comprises: depositing a layer of amorphous semiconductor material onto a crystalline semiconductor base, wherein the crystalline semiconductor base comprises a crystalline phase of a same semiconductor as the amorphous layer; and growing the layer of amorphous semiconductor material into a layer of crystalline semiconductor material that is epitaxially matched to the lattice structure of the crystalline semiconductor base by applying an optical energy that penetrates at least the amorphous semiconductor material.

  5. A self-aligned nano-fabrication process for vertical NbN-MgO-NbN Josephson junctions

    Science.gov (United States)

    Grimm, A.; Jebari, S.; Hazra, D.; Blanchet, F.; Gustavo, F.; Thomassin, J.-L.; Hofheinz, M.

    2017-10-01

    We present a new process for fabricating vertical NbN-MgO-NbN Josephson junctions using self-aligned silicon nitride spacers. It allows for a wide range of junction areas from 0.02 to several 100 μm2. At the same time, it is suited for the implementation of complex microwave circuits with transmission line impedances ranging from 1 {{k}}{{Ω }}. The constituent thin films and the finished junctions are characterized. The latter are shown to have high gap voltages (> 4 {mV}) and low sub-gap leakage currents.

  6. Self-planarized process for the fabrication of Josephson junction devices

    Energy Technology Data Exchange (ETDEWEB)

    Merker, Michael; Meckbach, Johannes Maximilian; Buehler, Simon; Il' in, Konstantin; Siegel, Michael [Institut fuer Mikro- und Nanoelektronische Systeme (IMS), Karlsruher Institut fuer Technologie (KIT) (Germany)

    2013-07-01

    High performance Josephson junction (JJ) devices require good control of lateral dimensions. Various JJ devices can benefit from sub-μm feature sizes. In our conventional Nb/Al-AlO{sub x}/Nb process, the minimum feature size is however limited by the step height of the layers beneath. In order to overcome this constraint, we refined our process, resulting in almost flat surfaces at intermediate processing steps without the need for time consuming chemical-mechanical polishing (CMP). Sub-μm feature sizes can be achieved using electron beam lithography (EBL). Due to the application of mix and match lithography, (combination of EBL and photolithography), the turn-around time is not increased significantly compared to our conventional process. Transport properties of sub-μm JJs at 4.2 K will be presented. Our JJ process yields excellent quality parameters with sub-μm feature sizes even in the third metal layer, and is therefore very promising for fabricating sub-μm JJs for quantum devices such as SQUIDs or receiver devices.

  7. Fabrication of Al/AlOx/Al Josephson junctions and superconducting quantum circuits by shadow evaporation and a dynamic oxidation process

    Institute of Scientific and Technical Information of China (English)

    Wu Yu-Lin; Deng Hui; Yu Hai-Feng; Xue Guang-Ming; Tian Ye; Li Jie; Chen Ying-Fei

    2013-01-01

    Besides serving as promising candidates for realizing quantum computing,superconducting quantum circuits are one of a few macroscopic physical systems in which fundamental quantum phenomena can be directly demonstrated and tested,giving rise to a vast field of intensive research work both theoretically and experimentally.In this paper we report our work on the fabrication of superconducting quantum circuits,starting from its building blocks:Al/AlOx/Al Josephson junctions.By using electron beam lithography patterning and shadow evaporation,we have fabricated aluminum Josephson junctions with a controllable critical current density (jc) and wide range of junction sizes from 0.01 μm2 up to 1 μm2.We have carried out systematical studies on the oxidation process in fabricating Al/AlOx/Al Josephson junctions suitable for superconducting flux qubits.Furthermore,we have also fabricated superconducting quantum circuits such as superconducting flux qubits and charge-flux qubits.

  8. Fabrication of nano-sized magnetic tunnel junctions using lift-off process assisted by atomic force probe tip.

    Science.gov (United States)

    Jung, Ku Youl; Min, Byoung-Chul; Ahn, Chiyui; Choi, Gyung-Min; Shin, Il-Jae; Park, Seung-Young; Rhie, Kungwon; Shin, Kyung-Ho

    2013-09-01

    We present a fabrication method for nano-scale magnetic tunnel junctions (MTJs), employing e-beam lithography and lift-off process assisted by the probe tip of atomic force microscope (AFM). It is challenging to fabricate nano-sized MTJs on small substrates because it is difficult to use chemical mechanical planarization (CMP) process. The AFM-assisted lift-off process enables us to fabricate nano-sized MTJs on small substrates (12.5 mm x 12.5 mm) without CMP process. The e-beam patterning has been done using bi-layer resist, the poly methyl methacrylate (PMMA)/ hydrogen silsesquioxane (HSQ). The PMMA/HSQ resist patterns are used for both the etch mask for ion milling and the self-aligned mask for top contact formation after passivation. The self-aligned mask buried inside a passivation oxide layer, is readily lifted-off by the force exerted by the probe tip. The nano-MTJs (160 nm x 90 nm) fabricated by this method show clear current-induced magnetization switching with a reasonable TMR and critical switching current density.

  9. Fabrication of high quality ferromagnetic Josephson junctions

    Energy Technology Data Exchange (ETDEWEB)

    Weides, M. [Institute for Solid State Research, Research Centre Juelich, D-52425 Juelich (Germany) and CNI-Center of Nanoelectronic Systems for Information Technology, Research Centre Juelich, D-52425 Juelich (Germany)]. E-mail: m.weides@fz-juelich.de; Tillmann, K. [Institute for Solid State Research, Research Centre Juelich, D-52425 Juelich (Germany); Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Research Centre Juelich, D-52425 Juelich (Germany); Kohlstedt, H. [Institute for Solid State Research, Research Centre Juelich, D-52425 Juelich (Germany); CNI-Center of Nanoelectronic Systems for Information Technology, Research Centre Juelich, D-52425 Juelich (Germany); Department of Material Science and Engineering and Department of Physics, University of Berkeley, CA 94720 (United States)

    2006-05-15

    We present ferromagnetic Nb/Al{sub 2}O{sub 3}/Ni{sub 60}Cu{sub 40}/Nb Josephson junctions (SIFS) with an ultrathin Al{sub 2}O{sub 3} tunnel barrier. The junction fabrication was optimized regarding junction insulation and homogeneity of current transport. Using ion-beam-etching and anodic oxidation we defined and insulated the junction mesas. The additional 2 nm thin Cu-layer below the ferromagnetic NiCu (SINFS) lowered interface roughness and ensured very homogeneous current transport. A high yield of junctional devices with j {sub c} spreads less than 2% was obtained.

  10. An Efficient Solution-Processed Intermediate Layer for Facilitating Fabrication of Organic Multi-Junction Solar Cells

    DEFF Research Database (Denmark)

    Ning Li; Baran, Derya; Forberich, Karen

    2013-01-01

    ):poly(styrenesulfonate) (PEDOT:PSS) is demonstrated for series-connected multi-junction organic solar cells (OSCs). Drying at 80 °C in air is sufficient for this solution-processed IML to obtain excellent functionality and reliability, which allow the use of most of high performance donor materials in the tandem structure...... simulations, which are reliable and promising guidelines for the design and investigation of multi-junction OSCs, are discussed. The outcome of optical and electrical simulations is in excellent agreement with the experimental data, indicating the outstanding efficiency and functionality of this solution...

  11. Fabrication of High-Quality Niobium Superconducting Tunnel Junctions

    Institute of Scientific and Technical Information of China (English)

    XU Qin-Yin; CAO Chun-Hai; LI Meng-Yue; JIANG Yi; ZHA Shi-Tong; KANG Lin; XU Wei-Wei; CHEN Jian; WU Pei-Heng

    2011-01-01

    @@ For high-quality superconducting tunnel junctions(STJS), it is necessary to reduce leakage current as much as possible.We describe the fabrication of niobium STJs using the selective niobium(Nb) etching process and various ways to minimize the leakage current.The experiment shows that the leakage current mainly comes from shorts in the tunnel barrier layer rather than those around the junction edges.Through systematic analysis of the thin film stress, surface morphology and modified junction structures, we fabricate high-quality Nb STJs with a gap voltage of 2.8 mV and a leakage current at 1 m V as low as 8.1 % and 0.023% at 4.2K and 0.3 K, respectively.

  12. Fabrication and characterization of the organic rectifying junctions by electrolysis

    Science.gov (United States)

    Karimov, Khasan; Ahmad, Zubair; Ali, Rashid; Noor, Adnan; Akmal, M.; Najeeb, M. A.; Shakoor, R. A.

    2017-08-01

    Unlike the conventional solution processable deposition techniques, in this study, we propose a novel and economical method for the fabrication of organic rectifying junctions. The solutions of the orange dye, copper phthalocyanine and NaCl were deposited on the surface-type interdigitated silver electrodes using electrolysis technique. Using the current-voltage (I-V) characteristics, the presence of rectifying behavior in the samples has been confirmed. This phenomenon, in principle, can be used for fabrication of the diodes, transistors and memory devices.

  13. Phase qubits fabricated with trilayer junctions

    Energy Technology Data Exchange (ETDEWEB)

    Weides, M; Bialczak, R C; Lenander, M; Lucero, E; Mariantoni, Matteo; Neeley, M; O' Connell, A D; Sank, D; Wang, H; Wenner, J; Yamamoto, T; Yin, Y; Cleland, A N; Martinis, J, E-mail: martin.weides@nist.gov, E-mail: martinis@physics.ucsb.edu [Department of Physics, University of California, Santa Barbara, CA 93106 (United States)

    2011-05-15

    We have developed a novel Josephson junction geometry with minimal volume of lossy isolation dielectric, suitable for higher quality trilayer junctions implemented in qubits. The junctions are based on in situ deposited trilayers with thermal tunnel oxide, have micron-sized areas and a low subgap current. In qubit spectroscopy only a few avoided level crossings are observed, and the measured relaxation time of T{sub 1{approx}}400 ns is in good agreement with the usual phase qubit decay time, indicating low loss due to the additional isolation dielectric.

  14. Investigation of inelastic electron tunneling spectra of metal-molecule-metal junctions fabricated using direct metal transfer method

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hyunhak; Hwang, Wang-Taek; Kim, Pilkwang; Kim, Dongku; Jang, Yeonsik; Min, Misook; Park, Yun Daniel; Lee, Takhee, E-mail: tlee@snu.ac.kr [Department of Physics and Astronomy, Institute of Applied Physics, Seoul National University, Seoul 151-747 (Korea, Republic of); Xiang, Dong [Institute of Modern Optics, Nankai University, Tianjin 300071 (China); Song, Hyunwook [Department of Applied Physics, Kyung Hee University, Yongin-si, Gyeonggi-do 446–701 (Korea, Republic of); Jeong, Heejun, E-mail: hjeong@hanyang.ac.kr [Department of Applied Physics, Hanyang University, Ansan 426-791 (Korea, Republic of)

    2015-02-09

    We measured the inelastic electron tunneling spectroscopy (IETS) characteristics of metal-molecule-metal junctions made with alkanethiolate self-assembled monolayers. The molecular junctions were fabricated using a direct metal transfer method, which we previously reported for high-yield metal-molecule-metal junctions. The measured IETS data could be assigned to molecular vibration modes that were determined by the chemical structure of the molecules. We also observed discrepancies and device-to-device variations in the IETS data that possibly originate from defects in the molecular junctions and insulating walls introduced during the fabrication process and from the junction structure.

  15. Fabrication and properties of sub-micrometric YBCO biepitaxial junctions

    Energy Technology Data Exchange (ETDEWEB)

    Stornaiuolo, D; Born, D; Barone, A [CNR-INFM Coherentia, Napoli (Italy); Cedergren, K; Bauch, T; Lombardi, F [MC2 Chalmers University of Technology, Goteborg (Sweden); Rotoli, G [CNISM and Universita dell' Aquila (Italy); Tafuri, F, E-mail: stornaiuolo@na.infh.i [Seconda Universita degli Studi di Napoli, Aversa (Italy)

    2009-03-01

    We report on the fabrication procedure and the transport properties of submicron grain boundary biepitaxial YBCO Josephson junctions. These first results are very encouraging and justify further expectations on improved performances for such types of devices. A reduced and more controlled faceting along the grain boundary interface, for instance, will better preserve intrinsic d-wave effects, and favour the study of fluxons dynamics.

  16. Fabrication of all-MgB Josephson junctions using MgO insulator layer

    Energy Technology Data Exchange (ETDEWEB)

    Oba, T. [Graduate School of Engineering, Iwate University, 4-3-5, Ueda, Morioka 020-8551 (Japan); Goto, S. [Lightom, 95-2 Sugo, Takizawa 020-0173 (Japan); Sasaki, S.; Nakanishi, Y.; Fujino, T. [Graduate School of Engineering, Iwate University, 4-3-5, Ueda, Morioka 020-8551 (Japan); Harada, Y. [JST Satellite Iwate, Japan Science and Technology Agency, 3-35-2 Iiokashinden, Morioka, Iwate 020-0852 (Japan); Nakamura, M. [Graduate School of Engineering, Iwate University, 4-3-5, Ueda, Morioka 020-8551 (Japan); Saito, A. [Department of Electrical Engineering, Yamagata University, 4-3-16, Jonan, Yonezawa, Yamagata 992-8510 (Japan); Yoshizawa, M. [Graduate School of Engineering, Iwate University, 4-3-5, Ueda, Morioka 020-8551 (Japan)], E-mail: yosizawa@iwate-u.ac.jp

    2008-09-15

    We report on the fabrication and properties of all-MgB{sub 2} tunnel junctions with an MgO barrier. Superconductor-insulator-superconductor (SIS) junctions were fabricated on C-plane sapphire substrates. MgB{sub 2} films were grown in an ultra-high vacuum in the 10{sup -9} Torr range. The MgO insulating layer was evaporated using an electron-beam gun. SIS junctions of 30 {mu}m in diameter were fabricated by standard photolithography and Ar ion milling techniques. The critical temperature (T{sub C}) of the lower MgB{sub 2} layer after the SIS junction fabrication process was 36.7 K, which remained the same as that of the bare MgB{sub 2} film. We observed tunneling behavior in the current-voltage (I-V) characteristics of the present junctions. A superconducting gap was clearly observed at around 2.7 mV (=2{delta})

  17. Fabrication of Josephson junctions by using an atomic force microscope

    CERN Document Server

    Song, I S; Kim, D H; Park, G S

    2000-01-01

    Josephson junctions have been fabricated by using an atomic foce microscope (AFM) for surface modification. YBCO films were fabricated on MgO substrates by using pulsed laser deposition. Surface modification of YBCO strips in the field of conductive AFM tips results in controlled and systematic growth of protrusions across the entire strip. Increasing the negative bias voltage to the AFM tip linearly increases the size of the modified structures. The offset superconducting transition temperature and the critical current values systematically shift to lower temperature and current values with increasing degree of AFM modification.

  18. Fabrication of high-quality submicron Nb/Al-AlOx/Nb tunnel junctions

    Institute of Scientific and Technical Information of China (English)

    Yu Hai-Feng; Cao Wen-Hui; Zhu Xiao-Bo; Yang Hai-Fang; Yu Hong-Wei; Ren Yu-Feng; Gu Chang-Zhi; Chen Geng-Hua; Zhao Shi-Ping

    2008-01-01

    Nb/Al-AlOx/Nb tunnel junctions are often used in the studies of macroscopic quantum phenomena and supercon-ducting qubit applications of the Josepheon devices. In this work, we describe a convenient and reliable process using electron beam lithography for the fabrication of high-quality, submicron-sized Nb/Al-AlOx/Nb Josephson junctions.The technique follows the well-known selective Nb etching process and produces high-quality junctions with Vm=100 mV at 2.3 K for the typical critical current density of 2.2 kA/cm2, which can be adjusted by controlling the oxygen pressure and oxidation time during the formation of the tunnelling barrier. We present the results of the temperature depen-dence of the sub-gap current and in-plane magnetic-field dependence of the critical current, and compare them with the theoretical predictions.

  19. Fabrication of Schottky Junction Between Au and SrTiO3

    Science.gov (United States)

    Inoue, Akira; Izumisawa, Kei; Uwe, Hiromoto

    2001-05-01

    A Schottky junction with a high rectification ratio between Au and La-doped SrTiO3 has been fabricated using a simple surface treatment. Highly La-doped (5%) SrTiO3 single crystals are annealed in O2 atmosphere at about 1000°C for 1 h and etched in HNO3 for more than five min. The HNO3 etching is performed in a globe box containing N2 to prevent pollution from the air. After the treatment, Au is deposited on the SrTiO3 surface in a vacuum (˜ 10-7 Torr) with an e-gun evaporator. The current voltage characteristics of the junction have shown excellent rectification properties, although junctions using neither annealed nor etched SrTiO3 exhibit high leak current in reverse voltage. The rectification ratio of the junction at 1 V is more than six orders of magnitude and there is no hysteresis in the current voltage spectra. The logarithm of the current is linear with the forward bias voltage. The ideal factor of the junction is estimated to be about 1.68. These results suggest that, if prevented from being pollution by the air, a good Schottky junction can be obtained by easy processes such as annealing in oxygen atmosphere and surface etching with acid.

  20. Junction-less poly-Ge FinFET and charge-trap NVM fabricated by laser-enabled low thermal budget processes

    Science.gov (United States)

    Huang, Wen-Hsien; Shieh, Jia-Min; Shen, Chang-Hong; Huang, Tzu-En; Wang, Hsing-Hsiang; Yang, Chih-Chao; Hsieh, Tung-Ying; Hsieh, Jin-Long; Yeh, Wen-Kuan

    2016-06-01

    A doping-free poly-Ge film as channel material was implemented by CVD-deposited nano-crystalline Ge and visible-light laser crystallization, which behaves as a p-type semiconductor, exhibiting holes concentration of 1.8 × 1018 cm-3 and high crystallinity (Raman FWHM ˜ 4.54 cm-1). The fabricated junctionless 7 nm-poly-Ge FinFET performs at an Ion/Ioff ratio over 105 and drain-induced barrier lowering of 168 mV/V. Moreover, the fast programming speed of 100 μs-1 ms and reliable retention can be obtained from the junctionless poly-Ge nonvolatile-memory. Such junctionless poly-Ge devices with low thermal budget are compatible with the conventional CMOS technology and are favorable for 3D sequential-layer integration and flexible electronics.

  1. Junction-less poly-Ge FinFET and charge-trap NVM fabricated by laser-enabled low thermal budget processes

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Wen-Hsien; Shen, Chang-Hong; Wang, Hsing-Hsiang; Yang, Chih-Chao; Hsieh, Tung-Ying; Hsieh, Jin-Long; Yeh, Wen-Kuan [National Nano Device Laboratories, No. 26, Prosperity Road 1, Hsinchu 30078, Taiwan (China); Shieh, Jia-Min, E-mail: jmshieh@narlabs.org.tw, E-mail: jmshieh@faculty.nctu.edu.tw [National Nano Device Laboratories, No. 26, Prosperity Road 1, Hsinchu 30078, Taiwan (China); Departments of Photonics and Institute of Electro-Optical Engineering, National Chiao-Tung University, Hsinchu 30010, Taiwan (China); Huang, Tzu-En [Departments of Photonics and Institute of Electro-Optical Engineering, National Chiao-Tung University, Hsinchu 30010, Taiwan (China)

    2016-06-13

    A doping-free poly-Ge film as channel material was implemented by CVD-deposited nano-crystalline Ge and visible-light laser crystallization, which behaves as a p-type semiconductor, exhibiting holes concentration of 1.8 × 10{sup 18 }cm{sup −3} and high crystallinity (Raman FWHM ∼ 4.54 cm{sup −1}). The fabricated junctionless 7 nm-poly-Ge FinFET performs at an I{sub on}/I{sub off} ratio over 10{sup 5} and drain-induced barrier lowering of 168 mV/V. Moreover, the fast programming speed of 100 μs–1 ms and reliable retention can be obtained from the junctionless poly-Ge nonvolatile-memory. Such junctionless poly-Ge devices with low thermal budget are compatible with the conventional CMOS technology and are favorable for 3D sequential-layer integration and flexible electronics.

  2. Fabrication and characteristics of a 4H-SiC junction barrier Schottky diode*

    Institute of Scientific and Technical Information of China (English)

    Chen Fengping; Zhang Yuming; Lü Hongliang; Zhang Yimen; Guo Hui; Guo Xin

    2011-01-01

    4H-SiC junction barrier Schottky (JBS) diodes with four kinds of design have been fabricated and characterized using two different processes in which one is fabricated by making the P-type ohmic contact of the anode independently, and the other is processed by depositing a Schottky metal multi-layer on the whole anode. The reverse performances are compared to find the influences of these factors. The results show that JBS diodes with field guard rings have a lower reverse current density and a higher breakdown voltage, and with independent Ptype ohmic contact manufacturing, the reverse performance of 4H-SiC JBS diodes can be improved effectively.Furthermore, the P-type ohmic contact is studied in this work.

  3. Fabrication and characteristics of a 4H-SiC junction barrier Schottky diode

    Energy Technology Data Exchange (ETDEWEB)

    Chen Fengping; Zhang Yuming; Lue Hongliang; Zhang Yimen; Guo Hui; Guo Xin, E-mail: fpchen@yeah.net [School of Microelectronics, Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices, Xidian University, Xi' an 710071 (China)

    2011-06-15

    4H-SiC junction barrier Schottky (JBS) diodes with four kinds of design have been fabricated and characterized using two different processes in which one is fabricated by making the P-type ohmic contact of the anode independently, and the other is processed by depositing a Schottky metal multi-layer on the whole anode. The reverse performances are compared to find the influences of these factors. The results show that JBS diodes with field guard rings have a lower reverse current density and a higher breakdown voltage, and with independent P-type ohmic contact manufacturing, the reverse performance of 4H-SiC JBS diodes can be improved effectively. Furthermore, the P-type ohmic contact is studied in this work. (semiconductor devices)

  4. Solution-route low-temperature fabrication of thin-film p-n junctions

    Science.gov (United States)

    Panamá, Gustavo; Ayag, Kevin; Kim, Hongdoo

    2016-11-01

    In this work, p-n junctions were fabricated at low temperature by means of UV-assisted thermal annealing. At 200 °C, remarkable rectifying and optical properties were observed due to the conversion of the sol-gel precursors to oxide films, which was aided by UV exposure. The resulting p-NiO/n-ZnO structures are featured as the thinnest ever reported (≈55 nm) based on a solution process with a large forward electrical current 10 -2 -10 -1 A cm-2 and the lowest leakage current (1 μA cm-2). UV light and precursor solution engineering contributed to form metal-oxide bonding at relatively low temperature in ambient conditions. The heterojunctions fabricated by the proper combination of these alternatives and simple processes were evaluated using UV-vis and FT-IR spectroscopy, FE-SEM, AFM, XRD, XPS, and I-V curves.

  5. Fabrication and characterization of high current-density, submicron, NbN/MgO/NbN tunnel junctions

    Science.gov (United States)

    Stern, J. A.; Leduc, Henry G.; Judas, A. J.

    1992-01-01

    At near-millimeter wavelengths, heterodyne receivers based on SIS tunnel junctions are the most sensitive available. However, in order to scale these results to submillimeter wavelengths, certain device properties should be scaled. The tunnel-junction's current density should be increased to reduce the RC product. The device's area should be reduced to efficiently couple power from the antenna to the mixer. Finally, the superconductor used should have a large energy gap to minimize RF losses. Most SIS mixers use Nb or Pb-alloy tunnel junctions; the gap frequency for these materials is approximately 725 GHz. Above the gap frequency, these materials exhibit losses similar to those in a normal metal. The gap frequency in NbN films is as-large-as 1440 GHz. Therefore, we have developed a process to fabricate small area (down to 0.13 sq microns), high current density, NbN/MgO/NbN tunnel junctions.

  6. Fabrication of superconducting tunnel junctions with embedded coil for applying magnetic field

    Science.gov (United States)

    Yamaguchi, Kenji; Nakagawa, Hiroshi; Aoyagi, Masahiro; Naruse, Masato; Myoren, Hiroaki; Taino, Tohru

    2016-11-01

    We have proposed and demonstrated a superconducting tunnel junction (STJ) with an embedded coil for applying a magnetic field. The STJ was fabricated on the coil, which was embedded in a Si substrate. The coil in the Si substrate consists of superconducting microstrip lines and applies a magnetic field to the STJ to suppress the dc Josephson current. The embedded coil was designed with a line and space of 3 μm and a thickness of 120 nm. To planarize the coil, we employed chemical mechanical polishing (CMP) in our fabrication process. In this STJ, the maximum current of the embedded coil was 28 mA, which corresponded to the maximum magnetic field of 11.76 mT.

  7. Niobium tunnel junction fabrication using e-gun evaporation and SNAP

    Science.gov (United States)

    Kortlandt, J.; van der Zant, H. S. J.; Schellingerhout, A. J. G.; Mooij, J. E.

    1990-11-01

    We have fabricated high quality small area Nb-Al-Al 2O 3-Nb junctions with SNAP, making use of e-beam evaporation in a 10 -5 Pa diffusion pumped vacuum system. Nominal dimensions of the junctions are 8x8, 4x4 and 2x2 μm 2. We obtain typical current densities of 5-6 × 10 +2A/cm 2 and (critical current) x (subgap resistance) products of 40 mV.

  8. Monolithic Fuel Fabrication Process Development

    Energy Technology Data Exchange (ETDEWEB)

    C. R. Clark; N. P. Hallinan; J. F. Jue; D. D. Keiser; J. M. Wight

    2006-05-01

    The pursuit of a high uranium density research reactor fuel plate has led to monolithic fuel, which possesses the greatest possible uranium density in the fuel region. Process developments in fabrication development include friction stir welding tool geometry and cooling improvements and a reduction in the length of time required to complete the transient liquid phase bonding process. Annealing effects on the microstructures of the U-10Mo foil and friction stir welded aluminum 6061 cladding are also examined.

  9. Hetero-junction photovoltaic device and method of fabricating the device

    Energy Technology Data Exchange (ETDEWEB)

    Aytug, Tolga; Christen, David K; Paranthaman, Mariappan Parans; Polat, Ozgur

    2014-02-10

    A hetero-junction device and fabrication method in which phase-separated n-type and p-type semiconductor pillars define vertically-oriented p-n junctions extending above a substrate. Semiconductor materials are selected for the p-type and n-type pillars that are thermodynamically stable and substantially insoluble in one another. An epitaxial deposition process is employed to form the pillars on a nucleation layer and the mutual insolubility drives phase separation of the materials. During the epitaxial deposition process, the orientation is such that the nucleation layer initiates propagation of vertical columns resulting in a substantially ordered, three-dimensional structure throughout the deposited material. An oxidation state of at least a portion of one of the p-type or the n-type semiconductor materials is altered relative to the other, such that the band-gap energy of the semiconductor materials differ with respect to stoichiometric compositions and the device preferentially absorbs particular selected bands of radiation.

  10. Excimer laser annealing: A gold process for CZ silicon junction formation

    Science.gov (United States)

    Wong, David C.; Bottenberg, William R.; Byron, Stanley; Alexander, Paul

    A cold process using an excimer laser for junction formation in silicon has been evaluated as a way to avoid problems associated with thermal diffusion. Conventional thermal diffusion can cause bulk precipitation of SiOx and SiC or fail to completely activate the dopant, leaving a degenerate layer at the surface. Experiments were conducted to determine the feasibility of fabricating high quality p-n junctions using a pulsed excimer laser for junction formation at remelt temperature with ion-implanted surfaces. Solar-cell efficiency exceeding 16 percent was obtained using Czochralski single-crystal silicon without benefit of back surface field or surface passivation. Characterization shows that the formation of uniform, shallow junctions (approximately 0.25 micron) by excimer laser scanning preserves the minority carrier lifetime that leads to high current collection. However, the process is sensitive to initial surface conditions and handling parameters that drive the cost up.

  11. Bismuth-catalyzed and doped silicon nanowires for one-pump-down fabrication of radial junction solar cells.

    Science.gov (United States)

    Yu, Linwei; Fortuna, Franck; O'Donnell, Benedict; Jeon, Taewoo; Foldyna, Martin; Picardi, Gennaro; Roca i Cabarrocas, Pere

    2012-08-08

    Silicon nanowires (SiNWs) are becoming a popular choice to develop a new generation of radial junction solar cells. We here explore a bismuth- (Bi-) catalyzed growth and doping of SiNWs, via vapor-liquid-solid (VLS) mode, to fabricate amorphous Si radial n-i-p junction solar cells in a one-pump-down and low-temperature process in a single chamber plasma deposition system. We provide the first evidence that catalyst doping in the SiNW cores, caused by incorporating Bi catalyst atoms as n-type dopant, can be utilized to fabricate radial junction solar cells, with a record open circuit voltage of V(oc) = 0.76 V and an enhanced light trapping effect that boosts the short circuit current to J(sc) = 11.23 mA/cm(2). More importantly, this bi-catalyzed SiNW growth and doping strategy exempts the use of extremely toxic phosphine gas, leading to significant procedure simplification and cost reduction for building radial junction thin film solar cells.

  12. Processing of Superconductor-Normal-Superconductor Josephson Edge Junctions

    Science.gov (United States)

    Kleinsasser, A. W.; Barner, J. B.

    1997-01-01

    The electrical behavior of epitaxial superconductor-normal-superconductor (SNS) Josephson edge junctions is strongly affected by processing conditions. Ex-situ processes, utilizing photoresist and polyimide/photoresist mask layers, are employed for ion milling edges for junctions with Yttrium-Barium-Copper-Oxide (YBCO) electrodes and primarily Co-doped YBCO interlayers.

  13. Sidewall GaAs tunnel junctions fabricated using molecular layer epitaxy

    Directory of Open Access Journals (Sweden)

    Takeo Ohno and Yutaka Oyama

    2012-01-01

    Full Text Available In this article we review the fundamental properties and applications of sidewall GaAs tunnel junctions. Heavily impurity-doped GaAs epitaxial layers were prepared using molecular layer epitaxy (MLE, in which intermittent injections of precursors in ultrahigh vacuum were applied, and sidewall tunnel junctions were fabricated using a combination of device mesa wet etching of the GaAs MLE layer and low-temperature area-selective regrowth. The fabricated tunnel junctions on the GaAs sidewall with normal mesa orientation showed a record peak current density of 35 000 A cm-2. They can potentially be used as terahertz devices such as a tunnel injection transit time effect diode or an ideal static induction transistor.

  14. p-n Junction Diodes Fabricated on Si-Si/Ge Heteroepitaxial Films

    Science.gov (United States)

    Das, K.; Mazumder, M. D. A.; Hall, H.; Alterovitz, Samuel A. (Technical Monitor)

    2000-01-01

    A set of photolithographic masks was designed for the fabrication of diodes in the Si-Si/Ge material system. Fabrication was performed on samples obtained from two different wafers: (1) a complete HBT structure with an n (Si emitter), p (Si/Ge base), and an n/n+ (Si collector/sub-collector) deposited epitaxially (MBE) on a high resistivity p-Si substrate, (2) an HBT structure where epitaxial growth was terminated after the p-type base (Si/Ge) layer deposition. Two different process runs were attempted for the fabrication of Si-Si/Ge (n-p) and Si/Ge-Si (p-n) junction diodes formed between the emitter-base and base-collector layers, respectively, of the Si-Si/Ge-Si HBT structure. One of the processes employed a plasma etching step to expose the p-layer in the structure (1) and to expose the e-layer in structure (2). The Contact metallization used for these diodes was a Cu-based metallization scheme that was developed during the first year of the grant. The plasma-etched base-collector diodes on structure (2) exhibited well-behaved diode-like characteristics. However, the plasma-etched emitter-base diodes demonstrated back-to-back diode characteristics. These back-to back characteristics were probably due to complete etching of the base-layer, yielding a p-n-p diode. The deep implantation process yielded rectifying diodes with asymmetric forward and reverse characteristics. The ideality factor of these diodes were between 1.6 -2.1, indicating that the quality of the MBE grown epitaxial films was not sufficiently high, and also incomplete annealing of the implantation damage. Further study will be conducted on CVD grown films, which are expected to have higher epitaxial quality.

  15. Niobium nano-SQUIDs based on sub-micron tunnel junction fabricated by three-dimensional Focused Ion Beam sculpting

    Science.gov (United States)

    Fretto, M.; Enrico, E.; De Leo, N.; Boarino, L.; Lacquaniti, V.; Granata, C.; Russo, R.; Vettoliere, A.

    2014-05-01

    A three dimensional nano-SQUID (Superconducting Quantum Interference Device) has been realized in a vertical configuration (with the loop in the same plane of Josephson Tunneling Junctions, JTJs). The loop area is 0.25 μm2 corresponding to a modulation period of about 5 mT, the square JTJs have a side length of 0.3 μm. Josephson junction's fabrication is carried out combining optical lithography to pattern trilayer and three dimensional (3D) Focused Ion Beam (FIB) sculpting technique to define the junctions' and the loop's areas. Two different ion etching processes were performed, perpendicular and parallel to the multilayer, resulting in a precise 3D structure. Finally, a standard anodization was performed to eliminate the unstructured surface material generated by the high energetic ion beam assuring high quality junctions. Electric transport characteristics of the nanodevice measured at T = 4.2 K are reported, in particular the current-voltage characteristics and critical current vs external magnetic field. The high modulation depth of the critical current (up to 70% of the Ic at zero magnetic flux) and the device reliability are very encouraging in view of nanoscience applications.

  16. Single wire radial junction photovoltaic devices fabricated using aluminum catalyzed silicon nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Ke, Y; Weng, X J; Kendrick, C E; Eichfeld, S M; Redwing, J M [Department of Materials Science and Engineering, Materials Research Institute, Pennsylvania State University, University Park, PA 16802 (United States); Wang, X; Yu, Y A; Yoon, H P; Mayer, T S [Department of Electrical Engineering, Materials Research Institute, Pennsylvania State University, University Park, PA 16802 (United States); Habib, Y M, E-mail: jmr31@psu.edu, E-mail: tsm2@psu.edu [Illuminex Corp., Lancaster, PA 17601 (United States)

    2011-11-04

    Single nanowire radial junction solar cell devices were fabricated using Si nanowires synthesized by Al-catalyzed vapor-liquid-solid growth of the p{sup +} core (Al auto-doping) and thin film deposition of the n{sup +}-shell at temperatures below 650 deg. C. Short circuit current densities of {approx} 11.7 mA cm{sup -2} were measured under 1-sun AM1.5G illumination, showing enhanced optical absorption. The power conversion efficiencies were limited to < 1% by the low open circuit voltage and fill factor of the devices, which was attributed to junction shunt leakage promoted by the high p{sup +}/n{sup +} doping. This demonstration of a radial junction device represents an important advance in the use of Al-catalyzed Si nanowire growth for low cost photovoltaics.

  17. Fabrication of sandwich-type MgB{sub 2}/Boron/MgB{sub 2} Josephson junctions with rapid annealing method

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Song; Wang, Xu; Ma, Junli; Cui, Ruirui; Deng, Chaoyong, E-mail: cydeng@gzu.edu.cn

    2015-11-15

    Sandwich-type MgB{sub 2}/Boron/MgB{sub 2} Josephson junctions were fabricated using magnetron sputtering system. The rapid-anneal process was adopted to replace traditional way of annealing, trying to solve the problem of interdiffusion and oxidation with multilayer films. The boron film was used as barrier layer to avoid the introduction of impurities and improve reproducibility of the junctions. The bottom MgB{sub 2} thin films deposited on c-plane sapphire substrate exhibits a critical temperature T{sub C} of 37.5 K and critical current density J{sub C} at 5 K of 8.7 × 10{sup 6} A cm{sup −2}. From the XRD pattern, the bottom MgB{sub 2} thin film shows c-axis orientation, whereas the top MgB{sub 2} became polycrystalline as Boron barrier layer grown thicker. Therefore, all junction samples show lower T{sub C} than single MgB{sub 2} thin film. The junctions exhibit excellent quasiparticle characteristics with ideal dependence on temperature and Boron barrier thickness. Subharmonic gap structure was appeared in conductance characteristics, which was attributed to the multiple Andreev reflections (MAR). The result demonstrates great promise of this new fabrication technology for MgB{sub 2} Josephson junction fabrication. - Highlights: • Sandwich-type MgB{sub 2}/Boron/MgB{sub 2} Josephson junctions were fabricated. • The junctions were annealed after deposition with the rapid-anneal process. • The highest critical current is 25.3 mA at 5 K and remains non-zero near 25 K. • Subharmonic gap features can be observed in the dI/dV – V curves.

  18. Structural and Electrical Properties of Heteroepitaxial Magnetic Oxide Junction Diode Fabricated by Pulsed Laser Deposition

    Science.gov (United States)

    Li, M. K.; Wong, K. H.

    2010-11-01

    Heteroepitaxial junctions formed by p-type strontium doped lanthanum manganite and n-type cobalt doped titanium dioxide were fabricated on LaAlO3 (100) substrates by pulsed laser deposition. The La0.7Sr0.3MnO3 (LSMO) layers were grown at 650° C and under 150 mTorr ambient oxygen pressure. They showed room temperature ferromagnetism and metallic-like electrical conduction with a resistivity of 0.015 ohm cm at 300 K. The CoxTi1-xO2[x = 0.05 and 0.1] (CTO), which, at anatase phase, was reported as a wide-band-gap dilute magnetic semiconductor, was deposited on the LSMO film surface at 600° C with an ambient oxygen pressure of 20 mTorr. The as-grown CTO films exhibited pure anatase crystalline phase and semiconductor-like conduction. Under optimized fabrication conditions the CTO/LSMO junction revealed a heteroepitaxial relationship of (004)CTO‖‖(001)LSMO‖‖(001)LAO. Electrical characterization of these p-n junctions yielded excellent rectifying characteristics with a current rectifying ratio over 1000 at room temperature. The electrical transport across these diodes was dominated by diffusion current at low current (low bias voltage) regime and by recombination current at high current (high bias voltage) regime. Our results have demonstrated an all-oxide spintronic junction diode with good transport property. The simultaneous of electrical and magnetic modulation in a diode junction is therefore potentially realizable.

  19. Fabrication of superconductor–ferromagnet–insulator–superconductor Josephson junctions with critical current uniformity applicable to integrated circuits

    Science.gov (United States)

    Ito, Hiroshi; Taniguchi, Soya; Ishikawa, Kouta; Akaike, Hiroyuki; Fujimaki, Akira

    2017-03-01

    Nb Josephson junctions (JJs) were fabricated with a Pd89Ni11 ferromagnetic interlayer and an AlO x tunnel barrier layer for use in large-scale superconducting integrated circuits. The junctions had a small critical current (I c) spread, where the standard deviation 1σ was less than 2% at 4.2 K for junctions with the same designed size. It was observed that the electrical behavior of the junctions could be controlled by manipulating the film thickness of the PdNi interlayer. The junctions behaved as a π-JJ for thicknesses of 9 and 11 nm, showing 1σ in the I c spread of 1.2% for 9 nm.

  20. Fabrication of magnetic tunnel junctions with epitaxial and textured ferromagnetic layers

    Science.gov (United States)

    Chang, Y. Austin; Yang, Jianhua Joshua

    2008-11-11

    This invention relates to magnetic tunnel junctions and methods for making the magnetic tunnel junctions. The magnetic tunnel junctions include a tunnel barrier oxide layer sandwiched between two ferromagnetic layers both of which are epitaxial or textured with respect to the underlying substrate upon which the magnetic tunnel junctions are grown. The magnetic tunnel junctions provide improved magnetic properties, sharper interfaces and few defects.

  1. Applications of nanosecond laser annealing to fabricating p-n homo junction on ZnO nanorods

    Science.gov (United States)

    Shimogaki, T.; Ofuji, T.; Tetsuyama, N.; Okazaki, K.; Higashihata, M.; Nakamura, D.; Ikenoue, H.; Asano, T.; Okada, T.

    2013-03-01

    Zinc oxide (ZnO) has attracted considerable attension due to its wide applications in particular ultra violet light emitting diode (UV-LED). In addition, the one-dimensional ZnO crystals are quite attractive as building blocks for light emitting devices like laser and LED, because of their high crystallinity and light confinement properties. However, a method for the realization of the stable p-type ZnO has not been well established. In our study, we have investigated the effect of the nanosecond laser irradiation to the ZnO nanorods as an ultrafast melting and recrystallizing process for realization of the p-type ZnO. Fabrication of the p-n homo junction along ZnO nanorods has been demonstrated using phosphorus ion implantation and ns-laser annealing by a KrF excimer laser. Rectifying I-V characteristics attributed to p-n junction were observed from the measurement of electrical properties. In addition, the penetration depth of laser annealed layer was measured by observing cathode luminescence images. Then, it was turned out that high repetition rate laser annealing can anneal ZnO nanorods over the optical-absorption length. In this report, optical, structural, and electrical characteristics of the phosphorus ion-implanted ZnO nanorods annealed by the KrF excimer laser are discussed.

  2. Metallic parts fabrication using the SIS process

    Science.gov (United States)

    Mojdeh, Mehdi

    Since early 1980s, quite a few techniques of Rapid Prototyping (RP), also known as Layered Manufacturing, have been developed. By building three-dimensional parts in a layer-by-layer additive manner, these techniques allow freeform fabrication of parts of complex geometry. Despite recent advances in fabrication of polymer parts, most of the existing rapid prototyping processes are still not capable of fabrication of accurate metallic parts with acceptable mechanical properties. Insufficient dimensional accuracy, limited number of materials, proper mechanical properties, required post machining and lack of repeatability between builds have greatly limited the market penetration of these techniques. This dissertation presents an innovative layered manufacturing technique for fabrication of dense metallic parts called Selective Inhibition Sintering (SIS), developed at the University of Southern California. The SIS-Metal technology adapts RP capabilities and extends them to the field of fabrication of metallic parts for a variety of applications such as tooling and low volume production. Using this process, a metallic part, with varying 3 dimensional geometries, can be automatically constructed from a wide range of materials. SIS-Metal is the only RP process which is suitable for fabrication of dense, complex shaped, accurate objects using a variety of materials. In the SIS-Metal process a metallic part is built layer by layer by deposition for each layer of an inhibitor material which defines the corresponding layer boundary and then filling the voids of the created geometry with metal powder; and compacting the layer formed to reach a high powder density. The resulting green part is then sintered in a furnace to yield the final functional part. In this research different inhibition techniques were explored and a series of single and multi layer parts was fabricated using the most promising inhibition technique, namely, macro-mechanical inhibition. Dimensional

  3. Fabrication of full high-T sub c superconducting YBa sub 2 Cu sub 3 O sub 7 sub - sub x trilayer junctions using a polishing technique

    CERN Document Server

    Kuroda, K; Takami, T; Ozeki, T

    2003-01-01

    We have successfully fabricated full high-T sub c superconducting YBa sub 2 Cu sub 3 O sub 7 sub - sub x (YBCO)/PrBa sub 2 Cu sub 3 O sub 7 sub - sub x (PBCO)/YBCO trilayer junctions, which have a simple device structure, such as a Pb-alloy-based Josephson tunneling junction. It has been demonstrated that a polishing technique is extremely useful in the fabrication process: it is effective in smoothing a coarse surface and gentling the slopes of the edges, or decreasing the slope angles. Owing to the polishing technique, the PBCO barrier layer and the upper YBCO layer have been notably thinned: the thicknesses of these layers are 10 nm and 250 nm, respectively. Junctions with the dimensions of 5 mu m x 5 mu m showed resistively shunted junction-like current-voltage curves with a typical critical current density of 110 A/cm sup 2 at 4.2 K. Furthermore, the operation of superconducting quantum interference devices has been demonstrated. (author)

  4. Micro and nano fabrication tools and processes

    CERN Document Server

    Gatzen, Hans H; Leuthold, Jürg

    2015-01-01

    For Microelectromechanical Systems (MEMS) and Nanoelectromechanical Systems (NEMS) production, each product requires a unique process technology. This book provides a comprehensive insight into the tools necessary for fabricating MEMS/NEMS and the process technologies applied. Besides, it describes enabling technologies which are necessary for a successful production, i.e., wafer planarization and bonding, as well as contamination control.

  5. Photoluminescence and diode characteristic of ZnO thin films/junctions fabricated by pulsed laser deposition (PLD) technique

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Kazuhiro; Komiyama, Takao; Chonan, Yasunori; Yamaguchi, Hiroyuki; Aoyama, Takashi [Department of Electronics and Information Systems, Akita Prefectural University, 84-4 Ebinokuchi, Tsuchiya, Yuri-honjo, Akita 015-0055 (Japan)

    2010-02-15

    ZnO:Ga and ZnO:P films were grown by a pulsed laser deposition (PLD) technique changing the dopant concentrations, and their photoluminescence (PL) spectra were obtained. Then, ZnO:P/ZnO:Ga junctions were fabricated and their junction characteristics were evaluated. As the Ga concentration increased in the films, the PL intensity was decreased while as the P concentration increased, the PL intensity was increased. The maximum PL intensities were obtained for the films of 0.5%(Ga) and 7.0% (P), respectively. Rectifying junction characteristics were observed only for the combination of 0.5-1.0% (Ga) and 5.0% (P) films. Mutual dopant diffusion is supposed to explain the relation between the PL and the junction characteristics. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Acid etching process for fabrication of Bi2Sr2CaCu2O8+x stack

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jie; CHEN Jian; WU JingBo; KANG Lin; XU WeiWei; WU PeiHeng

    2007-01-01

    We adopted a new method, acid etching process, to fabricate the intrinsic Josephson junctions based on the Bi2Sr2CaCu2O8+x single crystals. By soaking the crystals into the dilute hydrochloric acid, we fabricated a junction stack successfully, and meantime made the surrounding area insulated. A certain concentration of hydrochloric acid was used to maintain the roughness of the modified layer. The current-voltage characteristic was achieved through the four terminal measurement. We could control the junctions' number by changing the concentration and the soaking time. We also found that the thickness of the stack was equal to the average height of the insulation layer. Such a simple, convenient and controllable fabrication method with a high yield might widen the applications of the intrinsic Josephson junctions.

  7. Large-area, transparent, and flexible infrared photodetector fabricated using P-N junctions formed by N-doping chemical vapor deposition grown graphene.

    Science.gov (United States)

    Liu, Nan; Tian, He; Schwartz, Gregor; Tok, Jeffrey B-H; Ren, Tian-Ling; Bao, Zhenan

    2014-07-01

    Graphene is a highly promising material for high speed, broadband, and multicolor photodetection. Because of its lack of bandgap, individually gated P- and N-regions are needed to fabricate photodetectors. Here we report a technique for making a large-area photodetector on the basis of controllable fabrication of graphene P-N junctions. Our selectively doped chemical vapor deposition (CVD) graphene photodetector showed a ∼5% modulation of conductance under global IR irradiation. By comparing devices of various geometries, we identify that both the homogeneous and the P-N junction regions contribute competitively to the photoresponse. Furthermore, we demonstrate that our two-terminal graphene photodetector can be fabricated on both transparent and flexible substrates without the need for complex fabrication processes used in electrically gated three-terminal devices. This represents the first demonstration of a fully transparent and flexible graphene-based IR photodetector that exhibits both good photoresponsivity and high bending capability. This simple approach should facilitate the development of next generation high-performance IR photodetectors.

  8. A DLTS study of 4H-SiC-based p-n junctions fabricated by boron implantation

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, P. A., E-mail: Pavel.Ivanov@mail.ioffe.ru; Potapov, A. S.; Samsonova, T. P. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Korol' kov, O.; Sleptsuk, N. [Tallinn University of Technology, Department of Electronics (Estonia)

    2011-10-15

    Deep-level transient spectroscopy (DLTS) has been used to study p-n junctions fabricated by implantation of boron into epitaxial 4H-SiC films with n-type conductivity and the donor concentration (8-9) Multiplication-Sign 10{sup 14} cm{sup -3}. A DLTS signal anomalous in sign is observed; this signal is related to recharging of deep compensating boron-involved centers in the n-type region near the metallurgical boundary of the p-n junction.

  9. Fabrication and characterization of GaN junction field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, L.; Lester, L.F.; Baca, A.G.; Shul, R.J.; Chang, P.C.; Willison, C.L.; Mishra, U.K.; Denbaars, S.P.; Zolper, J.C.

    2000-01-11

    Junction field effect transistors (JFET) were fabricated on a GaN epitaxial structure grown by metal organic chemical vapor deposition. The DC and microwave characteristics, as well as the high temperature performance of the devices were studied. These devices exhibited excellent pinch-off and a breakdown voltage that agreed with theoretical predictions. An extrinsic transconductance (g{sub m}) of 48 mS/mm was obtained with a maximum drain current (I{sub D}) of 270 mA/mm. The microwave measurement showed an f{sub T} of 6 GHz and an f{sub max} of 12 GHz. Both the I{sub D} and the g{sub m} were found to decrease with increasing temperature, possibly due to lower electron mobility at elevated temperatures. These JFETs exhibited a significant current reduction after a high drain bias was applied, which was attributed to a partially depleted channel caused by trapped electrons in the semi-insulating GaN buffer layer.

  10. Characterization and reduction of capacitive loss induced by sub-micron Josephson junction fabrication in superconducting qubits

    Science.gov (United States)

    Dunsworth, A.; Megrant, A.; Quintana, C.; Chen, Zijun; Barends, R.; Burkett, B.; Foxen, B.; Chen, Yu; Chiaro, B.; Fowler, A.; Graff, R.; Jeffrey, E.; Kelly, J.; Lucero, E.; Mutus, J. Y.; Neeley, M.; Neill, C.; Roushan, P.; Sank, D.; Vainsencher, A.; Wenner, J.; White, T. C.; Martinis, John M.

    2017-07-01

    Josephson junctions form the essential non-linearity for almost all superconducting qubits. The junction is formed when two superconducting electrodes come within ˜1 nm of each other. Although the capacitance of these electrodes is a small fraction of the total qubit capacitance, the nearby electric fields are more concentrated in dielectric surfaces and can contribute substantially to the total dissipation. We have developed a technique to experimentally investigate the effect of these electrodes on the quality of superconducting devices. We use λ/4 coplanar waveguide resonators to emulate lumped qubit capacitors. We add a variable number of these electrodes to the capacitive end of these resonators and measure how the additional loss scales with the number of electrodes. We then reduce this loss with fabrication techniques that limit the amount of lossy dielectrics. We then use these techniques for the fabrication of Xmon qubits on a silicon substrate to improve their energy relaxation times by a factor of 5.

  11. Holliday junction processing enzymes as guardians of genome stability.

    Science.gov (United States)

    Sarbajna, Shriparna; West, Stephen C

    2014-09-01

    Holliday junctions (HJs) are four-stranded DNA intermediates that arise during the recombinational repair of DNA double-strand breaks (DSBs). Their timely removal is crucial for faithful chromosome segregation and genome stability. In mammalian cells, HJs are processed by the BTR (BLM-topoisomerase IIIα-RMI1-RMI2) complex, the SLX-MUS (SLX1-SLX4-MUS81-EME1) complex, and the GEN1 resolvase. Recent studies have linked the deficiency of one or more of these enzymes to perturbed DNA replication, impaired crosslink repair, chromosomal instability, and defective mitoses, coupled with the transmission of widespread DNA damage and high levels of mortality. We review these key advances and how they have cemented the status of HJ-processing enzymes as guardians of genome integrity and viability in mammalian cells. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Horizontal Assembly of Single Nanowire Diode Fabricated by p-n Junction GaN NW Grown by MOCVD

    Directory of Open Access Journals (Sweden)

    Ji-Hyeon Park

    2014-01-01

    Full Text Available Uniaxially p-n junction gallium nitride nanowires have been synthesized via metal-organic chemical vapor deposition method. Nanowires prepared on Si(111 substrates were found to grow perpendicular to the substrate, and the transmission electron microscopy studies demonstrated that the nanowires had singlecrystalline structures with a growth axis. The parallel assembly of the p-n junction nanowire was prepared on a Si substrate with a thermally grown SiO2 layer. The transport studies of horizontal gallium nitride nanowire structures assembled from p- and n-type materials show that these junctions correspond to well-defined p-n junction diodes. The p-n junction devices based on GaN nanowires suspended over the electrodes were fabricated and their electrical properties were investigated. The horizontally assembled gallium nitride nanowire diodes suspended over the electrodes exhibited a substantial increase in conductance under UV light exposure. Apart from the selectivity to different light wavelengths, high responsivity and extremely short response time have also been obtained.

  13. Fabricating an S&OP Process

    DEFF Research Database (Denmark)

    Lichen, Alex Yu

    Inspired by Latour’s (2005a) notion of matters of concern and M.C. Escher’s Circle Limit III as a representation of the Poincaré Disk, this study follows how an S&OP process was fabricated in a large Swedish manufacturing company. The study claims that when actors are fabricating the S&OP process......, local actors create emergent, ongoing and multiple matters of concern around it. The group demand chain, the actor who is responsible for guiding the implementation of the process, delegates the attempts to close these matters of concern to local actors located in separate times and spaces. As a result......, constituents of the S&OP process are dispersed in diverse local times and spaces rather than being coordinated in a single time and space by the group demand chain. Accounting is a set of matters of concern. The S&OP process and its purpose of integration come from an “absolute nothingness” – its minimal...

  14. Development of the Direct Fabrication Process for Plutonium Immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Congdon, J.W.

    2001-07-10

    The current baseline process for fabricating pucks for the Plutonium Immobilization Program includes granulation of the milled feed prior to compaction. A direct fabrication process was demonstrated that eliminates the need for granulation.

  15. Nanostructured p-type CZTS thin films prepared by a facile solution process for 3D p-n junction solar cells.

    Science.gov (United States)

    Park, Si-Nae; Sung, Shi-Joon; Sim, Jun-Hyoung; Yang, Kee-Jeong; Hwang, Dae-Kue; Kim, JunHo; Kim, Gee Yeong; Jo, William; Kim, Dae-Hwan; Kang, Jin-Kyu

    2015-07-07

    Nanoporous p-type semiconductor thin films prepared by a simple solution-based process with appropriate thermal treatment and three-dimensional (3D) p-n junction solar cells fabricated by depositing n-type semiconductor layers onto the nanoporous p-type thin films show considerable photovoltaic performance compared with conventional thin film p-n junction solar cells. Spin-coated p-type Cu2ZnSnS4 (CZTS) thin films prepared using metal chlorides and thiourea show unique nanoporous thin film morphology, which is composed of a cluster of CZTS nanograins of 50-500 nm, and the obvious 3D p-n junction structure is fabricated by the deposition of n-type CdS on the nanoporous CZTS thin films by chemical bath deposition. The photovoltaic properties of 3D p-n junction CZTS solar cells are predominantly affected by the scale of CZTS nanograins, which is easily controlled by the sulfurization temperature of CZTS precursor films. The scale of CZTS nanograins determines the minority carrier transportation within the 3D p-n junction between CZTS and CdS, which are closely related with the photocurrent of series resistance of 3D p-n junction solar cells. 3D p-n junction CZTS solar cells with nanograins below 100 nm show power conversion efficiency of 5.02%, which is comparable with conventional CZTS thin film solar cells.

  16. Fabrication of tunnel junctions on thick X-ray absorbing substrates of Nb and Ta

    NARCIS (Netherlands)

    Hamster, A.W.; Ferrari, E.; Adelerhof, D.J.; Brons, G.C.S.; Schoofs, I.J.E.; Flokstra, J.; Rogalla, H.; Bruijn, M.P.; Kiewiet, F.; Luiten, O.J.; Korte, de P.A.J.

    1996-01-01

    X-ray detectors based on absorber-junction combinations can combine a large detector area with position resolution and good energy resolution. We plan to use a thick, single crystal Nb or Ta absorber with readout tunnel junctions integrated on top as our next generation X-ray detector. The thickness

  17. Dissipative processes in superconducting nanodevices: Nanowire-resonators, shunted nanowires, and graphene proximity junctions

    Science.gov (United States)

    Brenner, Matthew W.

    The topic of superconducting nanowires has recently been an interesting field of research which has included the study of the superconductor to insulator transition (SIT), the observation of macroscopic quantum behavior such as quantum phase slips (QPS), and the potential use of nanowires as qubits. Superconducting coplanar microwave waveguide resonators have also become a popular way of studying superconducting junctions and qubits, as they provide an extremely low noise environment. For example, superconducting two-dimensional Fabry-Perot resonators have been used by other groups to make non-demolition measurements of a qubit. The motivation of this thesis will be the merging of the fields of superconducting nanowires and the technique of using superconducting microwave resonators to study junctions by incorporating a nanowire into the resonator itself at a current anti-node. By doing this, the nonlinear effects of the nanowire can be studied which may find application in single photon detectors, mixers, and the readout of qubits. We also employ the technique of molecular templating to fabricate some of the thinnest superconducting nanowires ever studied (down to ˜ 5 nm in diameter in some cases). In this thesis, we extend the understanding of the nonlinear properties of a nanowire-resonator system and investigate a new type of nonlinearity that involves a pulsing regime between the superconducting and normal phases of the nanowire. We develop a model, which describes the results quantitatively and by modeling the system, we are able to extract information regarding the relaxation time of the nanowire back into the superconducting state. We also study double nanowire-resonator systems where two closely spaced parallel nanowires interrupt the resonator center conductor and form a loop where vortex tunneling processes can occur. Using a double nanowire-resonator we are able to observe the Little-Parks effect at low temperatures (where the resistance of the wires

  18. YBa2Cu3O7-δ long Josephson junctions on bicrystal Zr1-xYxO2 substrates fabricated by preliminary topology masks

    Science.gov (United States)

    Masterov, D. V.; Parafin, A. E.; Revin, L. S.; Chiginev, A. V.; Skorokhodov, E. V.; Yunin, P. A.; Pankratov, A. L.

    2017-02-01

    YBa2Cu3O{}7-δ (YBCO) films were fabricated by magnetron sputtering with modification of the substrate surface by preliminary topology masks. Formation features of Josephson junctions on bicrystal Zr1-xYxO2 (YSZ) substrates have been considered. The structural and electrical properties of such junctions were investigated. As a result, the presented technology allows us to fabricate YBCO structures on YSZ substrates with a buffer cerium dioxide (CeO2) layer where YBCO film sputtering is the final stage of structure formation. In particular, long Josephson junctions with good characteristics have been fabricated by this technology and measured, allowing us to achieve critical currents of 80 mA for 150 um junctions.

  19. Synthesis of silicon carbide nano-junctions in a catalyst-assisted process

    Science.gov (United States)

    Deng, S. Z.; Wu, Z. S.; Zhou, Jun; Xu, N. S.; Chen, Jian; Chen, Jun

    2002-10-01

    Nano-Y-junctions and nano-staggered-junctions that are formed by SiC nanorods were grown at elevated temperatures in a catalyst-assisted process. Transmission electron microscopy shows that the nanorods are typically around 20 nm in diameter and around 2 μm in length. Nanorods with diameter down to below 2 nm may be observed from nano-junctions. High-resolution transmission electron microscopy shows that the nanorods are crystalline β-SiC.

  20. Ultra-shallow box-like profiles fabricated by pulsed UV-laser doping process

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, E.; Sigmon, T.W. [Stanford Univ., CA (United States); Weiner, K.H. [Lawrence Livermore National Lab., CA (United States)

    1993-03-23

    Ultra-shallow, box-like impurity profiles are produced using Gas Immersion Laser Doping (GILD) and then analyzed by spreading resistance profilometry (SRP) and secondary ion mass spectrometry (SIMS) to determine the impurity distribution. At high concentrations, the profiles obtained by SRP exhibit the expected box-like shape over the entire range of junction depths: The measured concentration within the junction region is uniform while the dopant gradient at the junction exceeds 0.5 decades/nm. In comparison, the same profiles analyzed by SIMS show a broader transition at the metallurgical junction. Caused by knock-ons and ion mixing during the sputtering process, this inaccuracy is reduced, but not eliminated by lowering the acceleration energy of the primary Cs{sup +} ion beam. At lower concentrations (< 10{sup 19}/cm{sup 3}), profiles analyzed by SRP exhibit shallower junctions than expected. Electrical measurements of diodes and Hall structures show that high-quality, ultra-shallow n{sup +}p, np and pn are fabricated with good dose control using GILD. For complete characterization of GILD, accurate measurement of both chemical and electrically-active dopant profiles are required. At present, neither SIMS nor SRP provides an entirely accurate impurity profile.

  1. Study on Performance and Processability of Sirofil Lightweight Worsted Fabric

    Institute of Scientific and Technical Information of China (English)

    李明菊; 范德炘; 葛惠萍; 侯祖龄

    2001-01-01

    The lightweight worsted fabric made of Sirofil yarn was developed and its textile performance was studied. By means of conventional testing, KES and FAST, it is concluded that with the coordination of proper fabric design and processing technique, the performance of this innovative fabric is superior to that of the conventional lightweight fabric Furthermore, it is predicted from the relevant parameters that its processability in the following suit manufacture is very desirable.

  2. High efficiency back-contact back-junction thin-film monocrystalline silicon solar cells from the porous silicon process

    Science.gov (United States)

    Haase, F.; Kajari-Schröder, S.; Brendel, R.

    2013-11-01

    This work demonstrates the fabrication of a 45 μm thick back-contact back-junction thin-film monocrystalline silicon solar cell from the porous silicon process with an energy conversion efficiency of 18.9%. We demonstrate an efficiency improvement of 5.4% absolute compared to our prior record of 13.5% for back-contact back-junction thin-film monocrystalline silicon solar cells. This increase in efficiency is achieved by reducing the recombination at the base contact using a back surface field and by increasing the generation with a front texture. We investigate the loss mechanisms in the cell using finite element simulations. A free energy loss analysis based on experiments and simulations determines the dominating loss mechanisms. The efficiency loss by base recombination is 0.8% absolute and the loss by base contact recombination is 0.5% absolute in the 18.9% efficiency cell.

  3. Edge-Geometry NbN/MgO/NbN Tunnel Junctions

    Science.gov (United States)

    Hunt, Brian D.; Leduc, Henry G.

    1991-01-01

    Superconductor/insulator/superconductor (SIS) tunnel junctions fabricated with base and counter electrodes of NbN separated by thin layers of MgO. Useful as submillimeter-wave mixers and fast switches. Use of edge geometry to define small junction makes possible to fabricate junction by process including conventional photolithography.

  4. A Rapid Process for Fabricating Gas Sensors

    Directory of Open Access Journals (Sweden)

    Chun-Ching Hsiao

    2014-07-01

    Full Text Available Zinc oxide (ZnO is a low-toxicity and environmentally-friendly material applied on devices, sensors or actuators for “green” usage. A porous ZnO film deposited by a rapid process of aerosol deposition (AD was employed as the gas-sensitive material in a CO gas sensor to reduce both manufacturing cost and time, and to further extend the AD application for a large-scale production. The relative resistance change (△R/R of the ZnO gas sensor was used for gas measurement. The fabricated ZnO gas sensors were measured with operating temperatures ranging from 110 °C to 180 °C, and CO concentrations ranging from 100 ppm to 1000 ppm. The sensitivity and the response time presented good performance at increasing operating temperatures and CO concentrations. AD was successfully for applied for making ZnO gas sensors with great potential for achieving high deposition rates at low deposition temperatures, large-scale production and low cost.

  5. Creating Sub-50 Nm Nanofluidic Junctions in PDMS Microfluidic Chip via Self-Assembly Process of Colloidal Particles.

    Science.gov (United States)

    Wei, Xi; Syed, Abeer; Mao, Pan; Han, Jongyoon; Song, Yong-Ak

    2016-03-13

    Polydimethylsiloxane (PDMS) is the prevailing building material to make microfluidic devices due to its ease of molding and bonding as well as its transparency. Due to the softness of the PDMS material, however, it is challenging to use PDMS for building nanochannels. The channels tend to collapse easily during plasma bonding. In this paper, we present an evaporation-driven self-assembly method of silica colloidal nanoparticles to create nanofluidic junctions with sub-50 nm pores between two microchannels. The pore size as well as the surface charge of the nanofluidic junction is tunable simply by changing the colloidal silica bead size and surface functionalization outside of the assembled microfluidic device in a vial before the self-assembly process. Using the self-assembly of nanoparticles with a bead size of 300 nm, 500 nm, and 900 nm, it was possible to fabricate a porous membrane with a pore size of ~45 nm, ~75 nm and ~135 nm, respectively. Under electrical potential, this nanoporous membrane initiated ion concentration polarization (ICP) acting as a cation-selective membrane to concentrate DNA by ~1,700 times within 15 min. This non-lithographic nanofabrication process opens up a new opportunity to build a tunable nanofluidic junction for the study of nanoscale transport processes of ions and molecules inside a PDMS microfluidic chip.

  6. Nb/A1- AlOx/Nb隧道结的制备研究%Fabrication on Nb/A1 - AlOx/Nb tunnel junction

    Institute of Scientific and Technical Information of China (English)

    肖伟; 曹春海; 李梦月; 许钦印; 卢亚鹏; 康琳; 许伟伟; 陈健; 吴培亨

    2012-01-01

    By improving etching process and insulating layer growth process, we fabricated superconducting tunnel junctions with good performance. In order to decrease the etching of oxide layer and substrate during RIE, CF4 was used as etching gas. SiO2 is grown by using PECVD, to improve the performance of SiO2 insulation layer. Greatly improve the performance of the tunnel junction.%通过改进RIE的刻蚀工艺和绝缘层的生长工艺,在SiO2/Si衬底上制备出了性能良好的超导Nb/A1 AlOx/Nb隧道结.采用CF4作为刻蚀气体,降低了RIE对结势垒层和衬底SiO2层的刻蚀.使用PECVD生长绝缘层SiO2,改善了绝缘性能,从而降低了隧道结的漏电流.

  7. Parametric Optical Signal Processing in Silicon Waveguides with Reverse-biased p-i-n Junctions

    DEFF Research Database (Denmark)

    Peucheret, C.; Da Ros, Francesco; Vukovic, Dragana;

    2014-01-01

    The use of silicon-on-insulator waveguides with free carriers removal using a reverse-biased p-i-n junction for parametric optical signal processing is reviewed. High-efficiency wavelength conversion and phase-sensitive regeneration are reported.......The use of silicon-on-insulator waveguides with free carriers removal using a reverse-biased p-i-n junction for parametric optical signal processing is reviewed. High-efficiency wavelength conversion and phase-sensitive regeneration are reported....

  8. Identification of RecQL1 as a Holliday junction processing enzyme in human cell lines

    Science.gov (United States)

    LeRoy, Gary; Carroll, Robert; Kyin, Saw; Seki, Masayuki; Cole, Michael D.

    2005-01-01

    Homologous recombination provides an effective way to repair DNA double-strand breaks (DSBs) and is required for genetic recombination. During the process of homologous recombination, a heteroduplex DNA structure, or a ‘Holliday junction’ (HJ), is formed. The movement, or branch migration, of this junction is necessary for recombination to proceed correctly. In prokaryotes, the RecQ protein or the RuvA/RuvB protein complex can promote ATP-dependent branch migration of Holliday junctions. Much less is known about the processing of Holliday junctions in eukaryotes. Here, we identify RecQL1 as a predominant ATP-dependent, HJ branch migrator present in human nuclear extracts. A reduction in the level of RecQL1 induced by RNA interference in HeLa cells leads to an increase in sister chromatid exchange. We propose that RecQL1 is involved in the processing of Holliday junctions in human cells. PMID:16260474

  9. Synthesis of magnetic tunnel junctions with full in situ atomic layer and chemical vapor deposition processes

    Energy Technology Data Exchange (ETDEWEB)

    Mantovan, R., E-mail: roberto.mantovan@mdm.imm.cnr.it [Laboratorio MDM, IMM-CNR, Via C. Olivetti 2, 20864 Agrate Brianza (Italy); Vangelista, S.; Kutrzeba-Kotowska, B.; Cocco, S.; Lamperti, A.; Tallarida, G. [Laboratorio MDM, IMM-CNR, Via C. Olivetti 2, 20864 Agrate Brianza (MB) (Italy); Mameli, D. [Laboratorio MDM, IMM-CNR, Via C. Olivetti 2, 20864 Agrate Brianza (Italy); Dipartimento di Scienze Chimiche, Universita di Cagliari, Cittadella Universitaria, 09042 Monserrato, Cagliari (Italy); Fanciulli, M. [Laboratorio MDM, IMM-CNR, Via C. Olivetti 2, 20864 Agrate Brianza (Italy); Dipartimento di Scienza dei Materiali, Universita degli studi Milano-Bicocca, Via R Cozzi 53, 20125 Milano (Italy)

    2012-05-01

    Magnetic tunnel junctions, i.e. the combination of two ferromagnetic electrodes separated by an ultrathin tunnel oxide barrier, are core elements in a large variety of spin-based devices. We report on the use of combined chemical vapor and atomic layer deposition processes for the synthesis of magnetic tunnel junctions with no vacuum break. Structural, chemical and morphological characterizations of selected ferromagnetic and oxide layers are reported, together with the evidence of tunnel magnetoresistance effect in patterned Fe/MgO/Co junctions.

  10. Fabrication of a Graphene/ZnO based p-n junction device and its ultraviolet photoresponse properties

    Science.gov (United States)

    Kwon, Young-Tae; Kang, Sung-Oong; Cheon, Ji-Ae; Song, Yoseb; Lee, Jong-Jin; Choa, Yong-Ho

    2017-09-01

    Graphene with a zero-bandgap energy is easily doped using a chemical dopant, and a shift upwards or downwards in the Fermi level is generated. Moreover, the integration of inorganic material into the doped graphene changes the physical and chemical properties of the material. For this purpose, we successfully fabricated a p-n junction device by depositing an n-typed ZnO layer on p-doped graphene and studied the ultraviolet (UV) photoresponse properties under a photocurrent (UV light on) and a dark current (UV light off). Two devices, lateral and vertical, were developed by alternating the thickness of the ZnO layer, and the photoresponse mechanisms were described on the basis of the contact potential difference.

  11. Disc resonator gyroscope fabrication process requiring no bonding alignment

    Science.gov (United States)

    Shcheglov, Kirill V. (Inventor)

    2010-01-01

    A method of fabricating a resonant vibratory sensor, such as a disc resonator gyro. A silicon baseplate wafer for a disc resonator gyro is provided with one or more locating marks. The disc resonator gyro is fabricated by bonding a blank resonator wafer, such as an SOI wafer, to the fabricated baseplate, and fabricating the resonator structure according to a pattern based at least in part upon the location of the at least one locating mark of the fabricated baseplate. MEMS-based processing is used for the fabrication processing. In some embodiments, the locating mark is visualized using optical and/or infrared viewing methods. A disc resonator gyroscope manufactured according to these methods is described.

  12. Junction studies on electrochemically fabricated p-n Cu(2)O homojunction solar cells for efficiency enhancement.

    Science.gov (United States)

    McShane, Colleen M; Choi, Kyoung-Shin

    2012-05-01

    p-n Cu(2)O homojunction solar cells were electrochemically fabricated by consecutively depositing an n-Cu(2)O layer on a p-Cu(2)O layer. In order to better understand the Fermi levels of the electrochemically grown polycrystalline p- and n-Cu(2)O layers and maximize the overall cell performance, the back and front contacts of the Cu(2)O homojunction cells were systematically changed and the I-V characteristics of the resulting cells were examined. The result shows that the intrinsic doping levels of the electrochemically prepared p-Cu(2)O and n-Cu(2)O layers are very low and they made almost Ohmic junctions with Cu metal with which previously studied p-Cu(2)O layers prepared by thermal oxidation of Cu foils are known to form Schottky junctions. The best cell performance (an η of 1.06%, a V(OC) of 0.621 V, an I(SC) of 4.07 mA cm(-2), and a fill factor (ff) of 42%) was obtained when the p-Cu(2)O layer was deposited on a commercially available ITO substrate as the back contact and a sputter deposited ITO layer was used as the front contact on the n-Cu(2)O layer. The unique features of the p-n Cu(2)O homojunction solar cell are discussed in comparison with other Cu(2)O-based heterojunction solar cells.

  13. FINAL PROCESS DEPENDENT DIMENSIONAL CHANGES OF DOUBLE KNIT FABRICS

    Directory of Open Access Journals (Sweden)

    Vedat ÖZYAZGAN

    2012-01-01

    Full Text Available In this paper Ne 30/1 cotton yarn obtained by using pure cotton fibers is employed. 1x1, 2x1 and 3x1 Rib fabrics were knitted with yarns at different gauges. During the knitting process, the tension was kept constant. In order to investigate the relaxation on the knitting process fabric samples were treated using three relaxation processes; dry, wet and full respectively. After each relaxation process, stitches dimensions were measured. As a result of these measurements, it is observed that as the relaxation increases the stitches length decreases while the stitches width increases. In rib knitting, As the fabric stretches increases the stitch length increases. As a result it is observed that as the stitch length increases, the width of the stitches increases linearly. In all rib fabrics, increase in the stitch density leads to an increase in the weight of the fabric.

  14. An improved fabrication process for Si-detector-compatible JFETs

    Energy Technology Data Exchange (ETDEWEB)

    Piemonte, Claudio [ITC-irst, Divisione Microsistemi, Via Sommarive, 18, 38050 Povo di Trento (Italy); Dalla Betta, Gian-Franco [Dipartimento di Informatica e Telecomunicazioni, Universita di Trento, Via Sommarive, 14, 38050 Povo di Trento (Italy)]. E-mail: dallabe@dit.unitn.it; Boscardin, Maurizio [ITC-irst, Divisione Microsistemi, Via Sommarive, 18, 38050 Povo di Trento (Italy); Gregori, Paolo [ITC-irst, Divisione Microsistemi, Via Sommarive, 18, 38050 Povo di Trento (Italy); Zorzi, Nicola [ITC-irst, Divisione Microsistemi, Via Sommarive, 18, 38050 Povo di Trento (Italy); Ratti, Lodovico [Dipartimento di Elettronica, Universita di Pavia, Via Ferrata 1, 27100 Pavia (Italy)

    2006-11-30

    We report on JFET devices fabricated on high-resistivity silicon with a radiation detector technology. The problems affecting previous versions of these devices have been thoroughly investigated and solved by developing an improved fabrication process, which allows for a sizeable enhancement in the JFET performance. In this paper, the main features of the fabrication technology are presented and selected results from the electrical and noise characterization of transistors are discussed.

  15. Streamlining CubeSat Solar Panel Fabrication Processes

    OpenAIRE

    Sandberg, Ariel; Smith, Timothy

    2016-01-01

    A critical facet of CubeSat fabrication is solar panel characterization and assembly. Though capable of producing flight quality solar subsystems, traditional methods of solar panel fabrication contain intrinsic inefficiencies and inconsistencies that compromise the subsystem’s overall reliability. Taking Michigan Exploration Laboratory’s (MXL) heritage solar panel procedures as a case study, this investigation sought to streamline the solar panel fabrication process to increase its yield, co...

  16. Process for fabrication of metal oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Tracy, C.E.; Benson, D.; Svensson, S.

    1990-07-17

    This invention is comprised of a method of fabricating metal oxide films from a plurality of reactants by inducing a reaction by plasma deposition among the reactants. The plasma reaction is effective for consolidating the reactants and producing thin films of metal oxides, e.g. electro-optically active transition metal oxides, at a high deposition rate. The presence of hydrogen during the plasma reaction enhances the deposition rate of the metal oxide. Various types of metal oxide films can be produced.

  17. Vertical current-flow enhancement via fabrication of GaN nanorod p–n junction diode on graphene

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Sung Ryong [Quantum-functional Semiconductor Research Center, Dongguk University-Seoul, 100-715 (Korea, Republic of); Department of physics, Dongguk University, Seoul, 100-715 (Korea, Republic of); Ram, S.D. Gopal; Lee, Seung Joo; Cho, Hak-dong; Lee, Sejoon [Quantum-functional Semiconductor Research Center, Dongguk University-Seoul, 100-715 (Korea, Republic of); Kang, Tae Won, E-mail: twkang@dongguk.edu [Quantum-functional Semiconductor Research Center, Dongguk University-Seoul, 100-715 (Korea, Republic of); Clean Energy and Nano Convergence Centre, Hindustan University, Chennai 600 016 (India); Kwon, Sangwoo; Yang, Woochul [Department of physics, Dongguk University, Seoul, 100-715 (Korea, Republic of); Shin, Sunhye [Soft-Epi Inc., 240 Opo-ro, Opo-eup, Gwangju-si, Gyeonggi-do (Korea, Republic of); Woo, Yongdeuk [Department of Mechanical and Automotive Engineering, Woosuk University, Chonbuk 565-701 (Korea, Republic of)

    2015-08-30

    Highlights: • Uniaxial p–n junction diode in GaN nanorod is made by Hydride vapor phase epitaxy method. • The p–n junction diode property is clearly observed from the fabricated uniaxial p–n junction nanorod GaN nanorod. • Graphene is used as a current spreading layer to reduce the lateral resistance up to 700 times when compared with the commercial sapphire substrate, which is clearly explained with the aid of an equivalent circuit. • Kelvin Force Probe microscopy method is employed to visualize the p- and n- regions in a single GaN nanorod. - Abstract: Mg doped GaN nanorods were grown on undoped n-type GaN nanorods uniaxial on monolayer graphene by hydride vapor phase epitaxy (HVPE) method. The monolayer graphene used as the bottom electrode and a substrate as well provides good electrical contact, acts as a current spreading layer, well suitable for the growth of hexagonal GaN nanorod. In addition it has a work function suitable to that of n-GaN. The formed p–n nanorods show a Schottky behavior with a turn on voltage of 3 V. Using graphene as the substrate, the resistance of the nanorod is reduced by 700 times when compared with the case without using graphene as the current spreading layer. The low resistance of graphene acts in parallel with the resistance of the GaN buffer layer, and reduces the resistance drastically. The formed p–n junction in a single GaN nanorod is visualized by Kelvin Force Probe Microscopy (KPFM) to have distinctively contrast p and n regions. The measured contact potential difference of p-and n-region has a difference of 103 mV which well confirms the formed regions are electronically different. Low temperature photoluminescence (PL) spectra give evidence of dopant related acceptor bound emission at 3.2 eV different from 3.4 eV of undoped GaN. The crystalline structure, compositional purity is confirmed by X-ray diffraction (XRD), Transmission and Scanning electron microcopies (SEM), (TEM), Energy dispersive analysis

  18. A Novel Design and Fabrication of Magnetic Random Access Memory Based on Nano-ring-type Magnetic Tunnel Junctions

    Institute of Scientific and Technical Information of China (English)

    X.F.Han; M. Ma; Y. Wang; Z.C. Wen; D.P. Liu; W.S.Zhan; H.X. Wei; Z.L.Peng; H.D. Yang; J.F. Feng; G.X.Du; Z.B.Sun; L.X. Jiang; Q.H. Qin

    2007-01-01

    Nano-ring-type magnetic tunnel junctions (NR-MTJs) with the layer structure of Ta(5)/Ir22Mn78(10)/Co75Fe25(2)/Ru(0.75)/Co60Fe20B20(3)/Al(0.6)-oxide/Co60Fe20B20(2.5)/Ta(3)/Ru(5) (thickness unit: nm)were nano-fabricated on the Si(100)/SiO2 substrate using magnetron sputtering deposition combined with the optical lithography, electron beam lithography (EBL) and Ar ion-beam etching techniques. The smaller NR-MTJs with the inner- and outer-diameter of around 50 and 100 nm and also their corresponding NR-MTJ arrays were nano-patterned. The tunnelling magnetoresistance (TMR & R) versus driving current (I) loops for a spin-polarized current switching were measured, and the TMR ratio of around 35% at room temperature were observed. The critical values of switching current for the free Co60Fe20B20 layer relative to the reference Co60Fe20B20 layer between parallel and anti-parallel magnetization states were between 0.50 and 0.75 mA in such NR-MTJs. It is suggested that the applicable MRAM fabrication with the density and capacity higher than 256 Mbit/inch2 even 6 Gbite/inch2 are possible using both 1 NR-MTJ+1 transistor structure and current switching mechanism based on based on our fabricated 4×4 MRAM demo devices.

  19. Optimizing The DSSC Fabrication Process Using Lean Six Sigma

    Science.gov (United States)

    Fauss, Brian

    Alternative energy technologies must become more cost effective to achieve grid parity with fossil fuels. Dye sensitized solar cells (DSSCs) are an innovative third generation photovoltaic technology, which is demonstrating tremendous potential to become a revolutionary technology due to recent breakthroughs in cost of fabrication. The study here focused on quality improvement measures undertaken to improve fabrication of DSSCs and enhance process efficiency and effectiveness. Several quality improvement methods were implemented to optimize the seven step individual DSSC fabrication processes. Lean Manufacturing's 5S method successfully increased efficiency in all of the processes. Six Sigma's DMAIC methodology was used to identify and eliminate each of the root causes of defects in the critical titanium dioxide deposition process. These optimizations resulted with the following significant improvements in the production process: 1. fabrication time of the DSSCs was reduced by 54 %; 2. fabrication procedures were improved to the extent that all critical defects in the process were eliminated; 3. the quantity of functioning DSSCs fabricated was increased from 17 % to 90 %.

  20. Phase diagrams of the Katz-Lebowitz-Spohn process on lattices with a junction

    Science.gov (United States)

    Tian, Bo; Jiang, Rui; Ding, Zhong-Jun; Hu, Mao-Bin; Wu, Qing-Song

    2013-06-01

    This paper studies the Katz-Lebowitz-Spohn (KLS) process on lattices with a junction, where particles move on parallel lattice branches that combine into a single lattice at the junction. It is shown that 11 kinds of phase diagrams could be observed, depending on the two parameters ɛ and δ in the KLS process. We have investigated the phase diagrams as well as bulk density analytically based on flow rate conservation and the extremal current principle. Extensive Monte Carlo computer simulations are performed, and it is found that they are in excellent agreement with theoretical prediction.

  1. Phase diagrams of the Katz-Lebowitz-Spohn process on lattices with a junction.

    Science.gov (United States)

    Tian, Bo; Jiang, Rui; Ding, Zhong-Jun; Hu, Mao-Bin; Wu, Qing-Song

    2013-06-01

    This paper studies the Katz-Lebowitz-Spohn (KLS) process on lattices with a junction, where particles move on parallel lattice branches that combine into a single lattice at the junction. It is shown that 11 kinds of phase diagrams could be observed, depending on the two parameters ε and δ in the KLS process. We have investigated the phase diagrams as well as bulk density analytically based on flow rate conservation and the extremal current principle. Extensive Monte Carlo computer simulations are performed, and it is found that they are in excellent agreement with theoretical prediction.

  2. Fabrication of BiOBr nanosheets@TiO{sub 2} nanobelts p–n junction photocatalysts for enhanced visible-light activity

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yang [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Huang, Xiang [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); School of Science, Tibet University, Lhasa 850000 (China); Tan, Xin [School of Science, Tibet University, Lhasa 850000 (China); Yu, Tao, E-mail: yutao@tju.edu.cn [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072 (China); Li, Xiangli [School of Environmental Science and Engineering, Tianjin University, Tianjin 300072 (China); Yang, Libin [College of Chemical Engineering and Materials Science, Tianjin University of Science & Technology, Tianjin Key Laboratory of Marine Resources and Chemistry, Tianjin 300457 (China); Wang, Shucong [School of Environmental Science and Engineering, Tianjin University, Tianjin 300072 (China)

    2016-03-01

    Graphical abstract: - Highlights: • BiOBr nanosheets@TiO{sub 2} nanobelts p–n junction photocatalysts have been synthesized. • The p–n junction photocatalysts improved water splitting and dye degradation activity. • BiOBr amount in the BiOBr@TiO{sub 2} photocatalysts was investigated. - Abstract: The construction of p–n junction structure is a smart strategy for improving the photocatalytic activity, since p–n junctions can inhibit the recombination of photo-induced charges. Herein, BiOBr nanosheets@TiO{sub 2} nanobelts p–n junction photocatalysts were prepared by assembling BiOBr nanosheets on the surface of TiO{sub 2} nanobelts via a hydrothermal route followed by a co-precipitation process. BiOBr@TiO{sub 2} p–n junction photocatalysts exhibited enhanced photocatalytic activity in photocatalytic H{sub 2} production over water splitting and photodegradation of Rhodamine B (RhB) under visible light irradiation. Mott–Schottky plots confirmed the formation of p–n junctions in the interface of BiOBr and TiO{sub 2}. The enhanced photocatalytic performance can be ascribed to the 1D nanostructure and the formation of p–n junctions. This work shows a potential application of low cost BiOBr as a substitute for noble metals in photocatalytic H{sub 2} production under visible light irradiation.

  3. Novel Fabrication Process for Micro Thermoelectric Generators (μTEGs)

    Science.gov (United States)

    Pelz, U.; Jaklin, J.; Rostek, R.; Kröner, M.; Woias, P.

    2015-12-01

    A cost effective bottom-up process for the fabrication of micro thermoelectric generators (μTEGs) was developed. It is based on a novel fabrication method involving a selectively sacrificial photoresist for the sequential galvanostatic electrodeposition of thermoelectric materials. The use of an industrial pick and placer (P&P) for dispensing the second photoresist allows for accurate and flexible μTEG designs. The process makes use of Ordyl® as a negative dry film photoresist template and sequential lamination steps for shaping all thermoelectric legs and contacts. All structures of the μTEG are generated in one photoresist multi-layer - this represents the most significant advantage of the process. The process uses a minimum of clean room processing for the preparation of pre-structured substrates for electrodeposition and therefore provides a cost-effective, highly flexible fabrication platform for research and development.

  4. Thickness Effect of Micro Speaker Copper Coil Fabrication Process

    Directory of Open Access Journals (Sweden)

    F. L. AYAT

    2011-07-01

    Full Text Available This paper present the advantage of using electroplating for making the thick layer of copper over the sputtering. The purpose of this paper is to fabricate the copper coil for microspeaker. The design and simulation of this copper coil shows that the 15 um thickness is needed. In order to fabricate this coil, copper plating is used. The electro-deposition process is well suited to make films of metals such as copper, gold and nickel. The films can be made in any thickness from ~1 µm to >100 µm. The deposition is best controlled when used with an external electrical potentiostate. However, it requires electrical contact to the substrate when immersed in the liquid bath. In any process, the surface of the substrate must have an electrically conducting coating before the deposition can be done. The result of this experimental research shows the easy and cheap way to fabricate the thick layer of copper for microspeacker fabrication.

  5. Process for fabricating continuous lengths of superconductor

    Science.gov (United States)

    Kroeger, Donald M.; List, III, Frederick A.

    1998-01-01

    A process for manufacturing a superconductor. The process is accomplished by depositing a superconductor precursor powder on a continuous length of a first substrate ribbon, overlaying a continuous length of a second substrate ribbon on said first substrate ribbon, and applying sufficient pressure to form a bound layered superconductor precursor between said first substrate ribbon and said second substrates ribbon. The layered superconductor precursor is then heat treated to form a super conductor layer.

  6. Computer Modeling of Complete IC Fabrication Process.

    Science.gov (United States)

    1984-01-01

    now makes the correlation S between process specification and resulting physically observ- Csea able parameters a viable and valuable design tool. Fig... journal is are generally provided at a paid-up royalty often not adequate to transfer research or an annual royalty fee. methodologies and findings to other

  7. Potential of mask production process for finer pattern fabrication

    Science.gov (United States)

    Yagawa, Keisuke; Ugajin, Kunihiro; Suenaga, Machiko; Kobayashi, Yoshihito; Motokawa, Takeharu; Hagihara, Kazuki; Saito, Masato; Itoh, Masamitsu

    2013-09-01

    Photomask used for optical lithography has been developed for purpose of fabrication a pattern along with finer designed rules and increase the productivity. With regard to pattern fabrication on mask, EB (Electron beam) mask writer has been used because it has high resolution beam. But in producing photomask, minimum pattern size on mask is hits a peak around 40nm by the resolution limit of ArF immersion systems. This value is easy to achieve by current EB writer. So, photomask process with EB writer has gotten attached to increase turnaround time. In next generation lithography such as EUV (Extreme ultraviolet) lithography and Nano-imprint lithography, it is enable to fabricate finer pattern beyond the resolution limit of ArF immersion systems. Thereby the pattern on a mask becomes finer rapidly. According to ITRS 2012, fabrication of finer patterns less than 20nm will be required on EUV mask and on NIL template. Especially in NIL template, less than 15nm pattern will be required half a decade later. But today's development of EB writer is aiming to increase photomask's productivity, so we will face a difficulty to fabricate finer pattern in near future. In this paper, we examined a potential of mask production process with EB writer from the view of finer pattern fabrication performances. We succeeded to fabricate hp (half-pitch) 17nm pattern on mask plate by using VSB (Variable Shaped Beam) type EB mask writer with CAR (Chemically Amplified Resist). This result suggests that the photomask fabrication process has the potential for sub-20nm generation mask production.

  8. Process for fabrication of large titanium diboride ceramic bodies

    Science.gov (United States)

    Moorhead, Arthur J.; Bomar, E. S.; Becher, Paul F.

    1989-01-01

    A process for manufacturing large, fully dense, high purity TiB.sub.2 articles by pressing powders with a sintering aid at relatively low temperatures to reduce grain growth. The process requires stringent temperature and pressure applications in the hot-pressing step to ensure maximum removal of sintering aid and to avoid damage to the fabricated article or the die.

  9. Computer modeling of complete IC fabrication process

    Science.gov (United States)

    Dutton, Robert W.

    1987-05-01

    The development of fundamental algorithms for process and device modeling as well as novel integration of the tools for advanced Integrated Circuit (IC) technology design is discussed. The development of the first complete 2D process simulator, SUPREM 4, is reported. The algorithms are discussed as well as application to local-oxidation and extrinsic diffusion conditions which occur in CMOS AND BiCMOS technologies. The evolution of 1D (SEDAN) and 2D (PISCES) device analysis is discussed. The application of SEDAN to a variety of non-silicon technologies (GaAs and HgCdTe) are considered. A new multi-window analysis capability for PISCES which exploits Monte Carlo analysis of hot carriers has been demonstrated and used to characterize a variety of silicon MOSFET and GaAs MESFET effects. A parallel computer implementation of PISCES has been achieved using a Hypercube architecture. The PISCES program has been used for a range of important device studies including: latchup, analog switch analysis, MOSFET capacitance studies and bipolar transient device for ECL gates. The program is broadly applicable to RAM and BiCMOS technology analysis and design. In the analog switch technology area this research effort has produced a variety of important modeling and advances.

  10. Fabrication of a magnetic-tunnel-junction-based nonvolatile logic-in-memory LSI with content-aware write error masking scheme achieving 92% storage capacity and 79% power reduction

    Science.gov (United States)

    Natsui, Masanori; Tamakoshi, Akira; Endoh, Tetsuo; Ohno, Hideo; Hanyu, Takahiro

    2017-04-01

    A magnetic-tunnel-junction (MTJ)-based video coding hardware with an MTJ-write-error-rate relaxation scheme as well as a nonvolatile storage capacity reduction technique is designed and fabricated in a 90 nm MOS and 75 nm perpendicular MTJ process. The proposed MTJ-oriented dynamic error masking scheme suppresses the effect of write operation errors on the operation result of LSI, which results in the increase in an acceptable MTJ write error rate up to 7.8 times with less than 6% area overhead, while achieving 79% power reduction compared with that of the static-random-access-memory-based one.

  11. Fabric-drying process in domestic dryers

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, V.; Moon, C.G. [Department of Mechanical Engineering, The University of Auckland, Auckland 1142 (New Zealand)

    2008-02-15

    A theoretical analysis of the drying process occurring inside the household electric tumbler clothes-dryer is performed to determine various thermo-physical parameters affecting the energy consumption and for the development of a simulation model. Experiments are conducted on a test set-up, based on a compact tumble-dryer, to measure the values of the parameters necessary for evaluating the performance. Widely-accepted economy standards are considered for comparison of simulation and experimental results. The simulation results are in reasonable agreement with experimental data. An empirical correlation for the specific moisture-extraction rate (SMER) is developed to translate energy-consumption information from one standard to the other. (author)

  12. Low-cost EUV collector development: design, process, and fabrication

    Science.gov (United States)

    Venables, Ranju D.; Goldstein, Michael; Engelhaupt, Darell; Lee, Sang H.; Panning, Eric M.

    2007-03-01

    Cost of ownership (COO) is an area of concern that may limit the adoption and usage of Extreme Ultraviolet Lithography (EUVL). One of the key optical components that contribute to the COO budget is the collector. The collectors being fabricated today are based on existing x-ray optic design and fabrication processes. The main contributors to collector COO are fabrication cost and lifetime. We present experimental data and optical modeling to demonstrate a roadmap for optimized efficiency and a possible approach for significant reduction in collector COO. Current state of the art collectors are based on a Wolter type-1 design and have been adapted from x-ray telescopes. It uses a long format that is suitable for imaging distant light sources such as stars. As applied to industrial equipment and very bright nearby sources, however, a Wolter collector tends to be expensive and requires significant debris shielding and integrated cooling solutions due to the source proximity and length of the collector shells. Three collector concepts are discussed in this work. The elliptical collector that has been used as a test bed to demonstrate alternative cost effective fabrication method has been optimized for collection efficiency. However, this fabrication method can be applied to other optical designs as well. The number of shells and their design may be modified to increase the collection efficiency and to accommodate different EUV sources The fabrication process used in this work starts with a glass mandrel, which is elliptical on the inside. A seed layer is coated on the inside of the glass mandrel, which is then followed by electroplating nickel. The inside/exposed surface of the electroformed nickel is then polished to meet the figure and finish requirements for the particular shell and finally coated with Ru or a multilayer film depending on the angle of incidence of EUV light. Finally the collector shell is released from the inside surface of the mandrel. There are

  13. Fuzzy TOPSIS for Multiresponse Quality Problems in Wafer Fabrication Processes

    Directory of Open Access Journals (Sweden)

    Chiun-Ming Liu

    2013-01-01

    Full Text Available The quality characteristics in the wafer fabrication process are diverse, variable, and fuzzy in nature. How to effectively deal with multiresponse quality problems in the wafer fabrication process is a challenging task. In this study, the fuzzy technique for order preference by similarity to an ideal solution (TOPSIS, one of the fuzzy multiattribute decision-analysis (MADA methods, is proposed to investigate the fuzzy multiresponse quality problem in integrated-circuit (IC wafer fabrication process. The fuzzy TOPSIS is one of the effective fuzzy MADA methods for dealing with decision-making problems under uncertain environments. First, a fuzzy TOPSIS methodology is developed by considering the ambiguity between quality characteristics. Then, a detailed procedure for the developed fuzzy TOPSIS approach is presented to show how the fuzzy wafer fabrication quality problems can be solved. Real-world data is collected from an IC semiconductor company and the developed fuzzy TOPSIS approach is applied to find an optimal combination of parameters. Results of this study show that the developed approach provides a satisfactory solution to the wafer fabrication multiresponse problem. This developed approach can be also applied to other industries for investigating multiple quality characteristics problems.

  14. New Insulation Application Process for Wind-And Magnet Fabrication

    Science.gov (United States)

    Kano, K. S.; Stewart, M. W.; Hooker, M. W.

    2008-03-01

    Wind-and-react processes offer a cost-effective means of fabricating large-scale Nb3Sn magnets, while also eliminating the need to manipulate the brittle superconductor after the high-temperature reaction process. Composite Technology Development, Inc. (CTD) has developed a hybrid inorganic/organic insulation system that can be co-processed with the Nb3Sn magnet at elevated temperatures. In this work, a new process was demonstrated for applying a thin, ceramic-based insulation that is compatible with wind-and-react processing. The insulation was applied to Rutherford cables using a continuous manufacturing process, and cable assemblies (i.e., 10-stacks) were fabricated and tested. The results of this work show that the insulation possesses a high strain tolerance, as well as the dielectric strength and fatigue resistance needed for high-field magnet applications.

  15. 2D InP photonic crystal fabrication process development

    NARCIS (Netherlands)

    Rong, B.; Van der Drift, E.; Van der Heijden, R.W.; Salemink, H.W.M.

    2006-01-01

    We have developed a reliable process to fabricate high quality 2D air-hole and dielectric column InP photonic crystals with a high aspect ratio on a STS production tool using ICP N2+Cl2 plasma. The photonic crystals have a triangular lattice with lattice constant of 400 nm and air-hole and dielectri

  16. A fabrication process for electrostatic microactuators with integrated gear linkages

    NARCIS (Netherlands)

    Legtenberg, Rob; Berenschot, Erwin; Elwenspoek, Miko; Fluitman, Jan H.

    1997-01-01

    A surface micromachining process is presented which has been used to fabricate electrostatic microactuators. These microactuators are interconnected with each other and linked to other movable microstructures by integrated gear linkages. The gear linkages consist of rotational and linear gear struct

  17. Fabrications aspects of microwave devices, including ramp-type high-Tc Josephson junctions and log-periodic antenna's

    NARCIS (Netherlands)

    Terpstra, D.; Rijnders, A.J.H.M.; Roesthuis, F.J.G.; Blank, D.H.A.; Gerritsma, G.J.; Rogalla, H.

    1993-01-01

    We describe the development of high-Tc Josephson junction devices for applications at millimeter wave frequencies. These devices consist of ramp type YBCO/PBCO/YBCO Josephson junctions that are equipped with a noble metal log-periodic antenna. Growth conditions of all layers, as well as etching, cle

  18. Molecular beam epitaxial growth of Bi2Te3 and Sb2Te3 topological insulators on GaAs (111 substrates: a potential route to fabricate topological insulator p-n junction

    Directory of Open Access Journals (Sweden)

    Zhaoquan Zeng

    2013-07-01

    Full Text Available High quality Bi2Te3 and Sb2Te3 topological insulators films were epitaxially grown on GaAs (111 substrate using solid source molecular beam epitaxy. Their growth and behavior on both vicinal and non-vicinal GaAs (111 substrates were investigated by reflection high-energy electron diffraction, atomic force microscopy, X-ray diffraction, and high resolution transmission electron microscopy. It is found that non-vicinal GaAs (111 substrate is better than a vicinal substrate to provide high quality Bi2Te3 and Sb2Te3 films. Hall and magnetoresistance measurements indicate that p type Sb2Te3 and n type Bi2Te3 topological insulator films can be directly grown on a GaAs (111 substrate, which may pave a way to fabricate topological insulator p-n junction on the same substrate, compatible with the fabrication process of present semiconductor optoelectronic devices.

  19. Thermoelectric microdevice fabricated by a MEMS-like electrochemical process

    Science.gov (United States)

    Snyder, G. Jeffrey; Lim, James R.; Huang, Chen-Kuo; Fleurial, Jean-Pierre

    2003-01-01

    Microelectromechanical systems (MEMS) are the basis of many rapidly growing technologies, because they combine miniature sensors and actuators with communications and electronics at low cost. Commercial MEMS fabrication processes are limited to silicon-based materials or two-dimensional structures. Here we show an inexpensive, electrochemical technique to build MEMS-like structures that contain several different metals and semiconductors with three-dimensional bridging structures. We demonstrate this technique by building a working microthermoelectric device. Using repeated exposure and development of multiple photoresist layers, several different metals and thermoelectric materials are fabricated in a three-dimensional structure. A device containing 126 n-type and p-type (Bi, Sb)2Te3 thermoelectric elements, 20 microm tall and 60 microm in diameter with bridging metal interconnects, was fabricated and cooling demonstrated. Such a device should be of technological importance for precise thermal control when operating as a cooler, and for portable power when operating as a micro power generator.

  20. Final audit report of remedial action construction at the UMTRA Project, Grand Junction, Colorado, processing site

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-02-01

    This final audit report (FAR) for remedial action at the Grand Junction, Colorado, Uranium Mill Tailings Remedial Action (UMTRA) Project processing site consists of a summary of the radiological surveillances/ audits, the quality assurance (QA) in-process surveillances, and the QA final close-out inspection performed by the US Department of Energy (DOE) and Technical Assistance Contractor (TAC). The FAR also summarizes other surveillances performed by the US Nuclear Regulatory Commission (NRC). To summarize, a total of one finding and 127 observations were noted during DOE/TAC audit and surveillance activities. The NRC noted general site-related observations during the OSCRs. Follow-up to responses required from MK-Ferguson for the DOE/TAC finding and observations indicated that all issues related to the Grand Junction processing site were resolved and closed out to the DOE`s satisfaction. The NRC OSCRs resulted in no issues related to the Grand Junction processing site requiring a response from MK-Ferguson.

  1. 3-Dimensional Microorifice Fabricated Utilizing Single Undercut Etching Process for Producing Ultrasmall Water and Chitosan Droplets

    Directory of Open Access Journals (Sweden)

    Che-Hsin Lin

    2013-01-01

    Full Text Available This research reports a microfluidic device for producing small droplets via a microorifice and a T-junction structure. The orifice is fabricated using an isotropic undercut etching process of amorphous glass materials. Since the equivalent hydraulic diameter of the produced microorifice can be as small as 1.1 μm, the microdevice can easily produce droplets of the size smaller than 10 μm in diameter. In addition, a permanent hydrophobic coating technique is also applied to modify the main channel to be hydrophobic to enhance the formation of water-based droplets. Experimental results show that the developed microfluidic chip with the ultrasmall orifice can steadily produce water-in-oil droplets with different sizes. Uniform water-in-oil droplets with the size from 60 μm to 6.5 μm in diameter can be formed by adjusting the flow rate ratio of the continuous phase and the disperse phases from 1 to 7. Moreover, curable linear polymer of chitosan droplets with the size smaller than 100 μm can also be successfully produced using the developed microchip device. The microfluidic T-junction with a micro-orifice developed in the present study provides a simple yet efficient way to produce various droplets of different sizes.

  2. A quantum chemical study from a molecular perspective: ionization and electron attachment energies for species often used to fabricate single-molecule junctions

    CERN Document Server

    Baldea, Ioan

    2015-01-01

    The accurate determination of the lowest electron attachment ($EA$) and ionization ($IP$) energies for molecules embedded in molecular junctions is important for correctly estimating, \\emph{e.g.}, the magnitude of the currents ($I$) or the biases ($V$) where an $I-V$-curve exhibits a significant non-Ohmic behavior. Benchmark calculations for the lowest electron attachment and ionization energies of several typical molecules utilized to fabricate single-molecule junctions characterized by n-type conduction (4,4'-bipyridine, 1,4-dicyanobenzene, and 4,4'-dicyano-1,1'-biphenyl) and p-type conduction (benzenedithiol, biphenyldithiol, hexanemonothiol, and hexanedithiol] based on the EOM-CCSD (equation-of-motion coupled-cluster singles and doubles) state-of-the-art method of quantum chemistry are presented. They indicate significant differences from the results obtained within current approaches to molecular transport. The present study emphasizes that, in addition to a reliable quantum chemical method, basis sets m...

  3. Vertically p-n-junctioned GaN nano-wire array diode fabricated on Si(111) using MOCVD.

    Science.gov (United States)

    Park, Ji-Hyeon; Kim, Min-Hee; Kissinger, Suthan; Lee, Cheul-Ro

    2013-04-07

    We demonstrate the fabrication of n-GaN:Si/p-GaN:Mg nanowire arrays on (111) silicon substrate by metal organic chemical vapor deposition (MOCVD) method .The nanowires were grown by a newly developed two-step growth process. The diameter of as-grown nanowires ranges from 300-400 nm with a density of 6-7 × 10(7) cm(-2). The p- and n-type doping of the nanowires is achieved with Mg and Si dopant species. Structural characterization by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) indicates that the nanowires are relatively defect-free. The room-temperature photoluminescence emission with a strong peak at 370 nm indicates that the n-GaN:Si/p-GaN:Mg nanowire arrays have potential application in light-emitting nanodevices. The cathodoluminscence (CL) spectrum clearly shows a distinct optical transition of GaN nanodiodes. The nano-n-GaN:Si/p-GaN:Mg diodes were further completed using a sputter coating approach to deposit Au/Ni metal contacts. The polysilazane filler has been etched by a wet chemical etching process. The n-GaN:Si/p-GaN:Mg nanowire diode was fabricated for different Mg source flow rates. The current-voltage (I-V) measurements reveal excellent rectifying properties with an obvious turn-on voltage at 1.6 V for a Mg flow rate of 5 sccm (standard cubic centimeters per minute).

  4. Turbine component, turbine blade, and turbine component fabrication process

    Energy Technology Data Exchange (ETDEWEB)

    Delvaux, John McConnell; Cairo, Ronald Ralph; Parolini, Jason Robert

    2017-05-30

    A turbine component, a turbine blade, and a turbine component fabrication process are disclosed. The turbine component includes ceramic matrix composite plies and a feature configured for preventing interlaminar tension of the ceramic matrix composite plies. The feature is selected from the group consisting of ceramic matrix composite tows or precast insert tows extending through at least a portion of the ceramic matrix composite plies, a woven fabric having fiber tows or a precast insert preventing contact between a first set of the ceramic matrix composite plies and a second set of the ceramic matrix composite plies, and combinations thereof. The process includes laying up ceramic matrix composite plies in a preselected arrangement and securing a feature configured for interlaminar tension.

  5. Effect of unequal injection rates on asymmetric exclusion processes with junction

    Institute of Scientific and Technical Information of China (English)

    Xiao Song; Liu Ming-Zhe; Wang Jian-Jun; Wang Hua

    2011-01-01

    In this paper, we investigate the effect of unequal injection rates on totally asymmetric simple exclusion processes (TASEPs) with a 2-input 1-output junction and parallel update. A mean-field approach is developed to deal with the junction that connects two sub-chains and the single main chain. We obtain the stationary particle currents, density profiles and phase diagrams. Interestingly, we find that the number of stationary-state phases is changeable depending on the value of α1 (α1 is the injection rate on the first sub-chain). When α1 > 1/3, there are seven stationary-state phases in the system, however when α1 < 1/3, only six stationary-state phases exist in the system. The theoretical calculations are shown to be in agreement with Monte Carlo simulations.

  6. Wavelength dependence of silicon avalanche photodiode fabricated by CMOS process

    Science.gov (United States)

    Mohammed Napiah, Zul Atfyi Fauzan; Hishiki, Takuya; Iiyama, Koichi

    2017-07-01

    Avalanche photodiodes fabricated by CMOS process (CMOS-APDs) have features of high avalanche gain below 10 V, wide bandwidth over 5 GHz, and easy integration with electronic circuits. In CMOS-APDs, guard ring structure is introduced for high-speed operation by canceling photo-generated carriers in the substrate at the sacrifice of the responsivity. We describe here wavelength dependence of the responsivity and the bandwidth of the CMOS-APDs with shorted and opened guard ring structure.

  7. A Novel Method to Fabricate Silicon Nanowire p-n Junctions by a Combination of Ion Implantation and in-situ Doping.

    Science.gov (United States)

    Kanungo, Pratyushdas; Kögler, Reinhard; Werner, Peter; Gösele, Ulrich; Skorupa, Wolfgang

    2009-11-08

    We demonstrate a novel method to fabricate an axial p-n junction inside oriented short vertical silicon nanowires grown by molecular beam epitaxy by combining ion implantation with in-situ doping. The lower halves of the nanowires were doped in-situ with boron (concentration ~1018cm-3), while the upper halves were doubly implanted with phosphorus to yield a uniform concentration of 2 × 1019 cm-3. Electrical measurements of individually contacted nanowires showed excellent diode characteristics and ideality factors close to 2. We think that this value of ideality factors arises out of a high rate of carrier recombination through surface states in the native oxide covering the nanowires.

  8. Development and process control of magnetic tunnel junctions for magnetic random access memory devices

    Science.gov (United States)

    Kula, Witold; Wolfman, Jerome; Ounadjela, Kamel; Chen, Eugene; Koutny, William

    2003-05-01

    We report on the development and process control of magnetic tunnel junctions (MTJs) for magnetic random access memory (MRAM) devices. It is demonstrated that MTJs with high magnetoresistance ˜40% at 300 mV, resistance-area product (RA) ˜1-3 kΩ μm2, low intrinsic interlayer coupling (Hin) ˜2-3 Oe, and excellent bit switching characteristics can be developed and fully integrated with complementary metal-oxide-semiconductor circuitry into MRAM devices. MTJ uniformity and repeatability level suitable for mass production has been demonstrated with the advanced processing and monitoring techniques.

  9. Hyperbolic Metamaterial Feasible for Fabrication with Direct Laser Writing Processes

    CERN Document Server

    Zhang, Xu; Güney, Durdu Ö

    2015-01-01

    Stimulated emission depletion microscopy inspired direct laser writing (STED-DLW) processes can offer diffraction-unlimited fabrication of 3D-structures, not possible with traditional electron-beam or optical lithography. We propose a hyperbolic metamaterial for fabrication with STED-DLW. First, we design meandering wire structures with three different magnetic dipoles which can be excited under different incidences of light. Then, based on effective parameters corresponding to normal incidence and lateral incidence, we find that the hyperbolic dispersion relation for five-layer structure appears between 15THz to 20THz. Finally, we investigate the influence of imaginary parts of the effective parameters on the metamaterial dispersion. The proposed metamaterial structure has also potential for three-dimensionally isotropic permeability despite geometric anisotropy.

  10. One-step electrodeposition process to fabricate cathodic superhydrophobic surface

    Energy Technology Data Exchange (ETDEWEB)

    Chen Zhi, E-mail: c2002z@nwpu.edu.cn [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710129 (China); Li Feng [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710129 (China); Hao Limei [Department of Applied Physics, Xi' an University of Science and Technology, Xi' an 710054 (China); Chen Anqi; Kong Youchao [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710129 (China)

    2011-12-01

    In this work, a rapid one-step process is developed to fabricate superhydrophobic cathodic surface by electrodepositing copper plate in an electrolyte solution containing manganese chloride (MnCl{sub 2}{center_dot}4H{sub 2}O), myristic acid (CH{sub 3}(CH{sub 2}){sub 12}COOH) and ethanol. The superhydrophobic surfaces were characterized by means of scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The shortest electrolysis time for fabricating a superhydrophobic surface is about 1 min, the measured maximum contact angle is 163 Degree-Sign and rolling angle is less than 3 Degree-Sign . Furthermore, this method can be easily extended to other conductive materials. The approach is time-saving and cheap, and it is supposed to have a promising future in industrial fields.

  11. Polyimide Humidity Integrated Sensor Fabricated Using the MEMS Process

    Institute of Scientific and Technical Information of China (English)

    Dianzhong Wen

    2006-01-01

    This paper reports on the fabrication and sensing characteristics of Polyimide-based humidity sensor, based on that, a new integrated circuit of humidity measurement has been designed. It is a novel capacitive-type systems on a chip structure using the MEMS process. The results show that the new sensor presents sensing characteristics over a humidity range from 10%~70% RH at 20℃, and the sensor is able to fabricated together with Ics technology. The result shows that integration of humidity sensor with integrated circuit of humidity measurement is considerably easier when they are built in sensing groove. The appeal of a new structure like this brings the possibility of applications that would require the flexibility of simple screen printing.

  12. A solar module fabrication process for HALE solar electric UAVs

    Energy Technology Data Exchange (ETDEWEB)

    Carey, P.G.; Aceves, R.C.; Colella, N.J.; Williams, K.A. [Lawrence Livermore National Lab., CA (United States); Sinton, R.A. [Private Consultant, San Jose, CA (United States); Glenn, G.S. [Spectrolab, Inc., Sylmar, CA (United States)

    1994-12-12

    We describe a fabrication process used to manufacture high power-to-weight-ratio flexible solar array modules for use on high-altitude-long-endurance (HALE) solar-electric unmanned air vehicles (UAVs). These modules have achieved power-to-weight ratios of 315 and 396 W/kg for 150{mu}m-thick monofacial and 110{mu}m-thick bifacial silicon solar cells, respectively. These calculations reflect average module efficiencies of 15.3% (150{mu}m) and 14.7% (110{mu}m) obtained from electrical tests performed by Spectrolab, Inc. under AMO global conditions at 25{degrees}C, and include weight contributions from all module components (solar cells, lamination material, bypass diodes, interconnect wires, and adhesive tape used to attach the modules to the wing). The fabrication, testing, and performance of 32 m{sup 2} of these modules will be described.

  13. One-step electrodeposition process to fabricate cathodic superhydrophobic surface

    Science.gov (United States)

    Chen, Zhi; Li, Feng; Hao, Limei; Chen, Anqi; Kong, Youchao

    2011-12-01

    In this work, a rapid one-step process is developed to fabricate superhydrophobic cathodic surface by electrodepositing copper plate in an electrolyte solution containing manganese chloride (MnCl2·4H2O), myristic acid (CH3(CH2)12COOH) and ethanol. The superhydrophobic surfaces were characterized by means of scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The shortest electrolysis time for fabricating a superhydrophobic surface is about 1 min, the measured maximum contact angle is 163° and rolling angle is less than 3°. Furthermore, this method can be easily extended to other conductive materials. The approach is time-saving and cheap, and it is supposed to have a promising future in industrial fields.

  14. Design and fabrication of a perpendicular magnetic tunnel junction based nonvolatile programmable switch achieving 40% less area using shared-control transistor structure.

    Science.gov (United States)

    Suzuki, D; Natsui, M; Mochizuki, A; Miura, S; Honjo, H; Kinoshita, K; Fukami, S; Sato, H; Ikeda, S; Endoh, T; Ohno, H; Hanyu, T

    2014-05-07

    A compact nonvolatile programmable switch (NVPS) using 90 nm CMOS technology together with perpendicular magnetic tunnel junction (p-MTJ) devices is fabricated for zero-standby-power field-programmable gate array. Because routing information does not change once it is programmed into an NVPS, high-speed read and write accesses are not required and a write-control transistor can be shared among all the NVPSs, which greatly simplifies structure of the NVPS. In fact, the effective area of the proposed NVPS is reduced by 40% compared to that of a conventional MTJ-based NVPS. The instant on/off behavior without external nonvolatile memory access is also demonstrated using the fabricated test chip.

  15. Gap Junctions

    Science.gov (United States)

    Nielsen, Morten Schak; Axelsen, Lene Nygaard; Sorgen, Paul L.; Verma, Vandana; Delmar, Mario; Holstein-Rathlou, Niels-Henrik

    2013-01-01

    Gap junctions are essential to the function of multicellular animals, which require a high degree of coordination between cells. In vertebrates, gap junctions comprise connexins and currently 21 connexins are known in humans. The functions of gap junctions are highly diverse and include exchange of metabolites and electrical signals between cells, as well as functions, which are apparently unrelated to intercellular communication. Given the diversity of gap junction physiology, regulation of gap junction activity is complex. The structure of the various connexins is known to some extent; and structural rearrangements and intramolecular interactions are important for regulation of channel function. Intercellular coupling is further regulated by the number and activity of channels present in gap junctional plaques. The number of connexins in cell-cell channels is regulated by controlling transcription, translation, trafficking, and degradation; and all of these processes are under strict control. Once in the membrane, channel activity is determined by the conductive properties of the connexin involved, which can be regulated by voltage and chemical gating, as well as a large number of posttranslational modifications. The aim of the present article is to review our current knowledge on the structure, regulation, function, and pharmacology of gap junctions. This will be supported by examples of how different connexins and their regulation act in concert to achieve appropriate physiological control, and how disturbances of connexin function can lead to disease. © 2012 American Physiological Society. Compr Physiol 2:1981-2035, 2012. PMID:23723031

  16. Gap junctions.

    Science.gov (United States)

    Nielsen, Morten Schak; Axelsen, Lene Nygaard; Sorgen, Paul L; Verma, Vandana; Delmar, Mario; Holstein-Rathlou, Niels-Henrik

    2012-07-01

    Gap junctions are essential to the function of multicellular animals, which require a high degree of coordination between cells. In vertebrates, gap junctions comprise connexins and currently 21 connexins are known in humans. The functions of gap junctions are highly diverse and include exchange of metabolites and electrical signals between cells, as well as functions, which are apparently unrelated to intercellular communication. Given the diversity of gap junction physiology, regulation of gap junction activity is complex. The structure of the various connexins is known to some extent; and structural rearrangements and intramolecular interactions are important for regulation of channel function. Intercellular coupling is further regulated by the number and activity of channels present in gap junctional plaques. The number of connexins in cell-cell channels is regulated by controlling transcription, translation, trafficking, and degradation; and all of these processes are under strict control. Once in the membrane, channel activity is determined by the conductive properties of the connexin involved, which can be regulated by voltage and chemical gating, as well as a large number of posttranslational modifications. The aim of the present article is to review our current knowledge on the structure, regulation, function, and pharmacology of gap junctions. This will be supported by examples of how different connexins and their regulation act in concert to achieve appropriate physiological control, and how disturbances of connexin function can lead to disease. © 2012 American Physiological Society. Compr Physiol 2:1853-1872, 2012.

  17. Fabricating Nanogaps in YBa2 Cu3 O7 -δ for Hybrid Proximity-Based Josephson Junctions

    Science.gov (United States)

    Baghdadi, Reza; Arpaia, Riccardo; Charpentier, Sophie; Golubev, Dmitri; Bauch, Thilo; Lombardi, Floriana

    2015-07-01

    The advances of nanotechnologies applied to high-critical-temperature superconductors (HTSs) have recently given a huge boost to the field, opening new prospectives for their integration in hybrid devices. The feasibility of this research goes through the realization of HTS nanogaps with superconductive properties close to the as-grown bulk material at the nanoscale. Here we present a fabrication approach allowing the realization of YBa2 Cu3 O7 -δ (YBCO) nanogaps with dimensions as small as 35 nm. To assess the quality of the nanogaps, we measure, before and after an ozone treatment, the current-voltage characteristics and the resistance versus temperature of YBCO nanowires with various widths and lengths, fabricated by using different lithographic processes. The analysis of the superconducting transition with a thermally activated vortex-entry model allows us to determine the maximum damage the nanowires undergo during the patterning which relates to the upper bound for the dimension of the nanogap. We find that the effective width of the nanogap is of the order of 100 nm at the superconducting transition temperature while retaining the geometrical value of about 35 nm at lower temperatures. The feasibility of the nanogaps for hybrid Josephson devices is demonstrated by bridging them with thin Au films. We detect a Josephson coupling up to 85 K with an almost ideal magnetic-field response of the Josephson current. These results pave the way for the realization of complex hybrid devices, where tiny HTS nanogaps can be instrumental to study the Josephson effect through barriers such as topological insulators or graphene.

  18. Magnetic fabric and welding processes in high-grade tuffs

    Science.gov (United States)

    Pioli, L.; Ort, M.; Lanza, R.; Rosi, M.

    2003-04-01

    The welding fabric of tuffs is generally quantified through two main parameters: porosity and fiamme aspect ratio. However, these parameters are not useful for high-grade ignimbrites that display features indicating extensive rheomorphic flow, partial to complete obliteration of primary vitroclastic textures, and syn-depositional welding rather than load-related compaction. In this case, a 3D-microstructural characterization of the rock fabric is a fundamental proxy for the assessment of the dynamics and duration of welding processes. We have investigated the relations between magnetic fabric and welding textures in a rhyolitic, high-grade ignimbrite from the Sulcis volcanic District (SW Sardinia, Italy). The ignimbrite is characterized by dense welding throughout its preserved thickness and by regular lateral and vertical variations of welding, devitrification and vesiculation facies. Field and structural data indicate that syn-depositional welding and non-particulate (NP) flow were extensive and continuous during the emplacement of the ignimbrite. Paleomagnetic measurements of AMS, NRM, and AIRM of samples from the tuff indicate that the magnetic fabric is strain-sensitive and it is not significantly affected by post-depositional, static processes such as devitrification and vapor-phase alteration; in particular, magnetic susceptibility of the rock and the welding texture correlate well in terms of shape and orientation of the anisotropy ellipsoid. The direction of the K1 axis is indicative of the flow direction in the site of measurement. The anisotropy degree (P) increases with increasing welding and foliation (F) and lineation (L) are directly related to the strain facies. Onset of welding increased the degree of anisotropy and foliation; a non particulate, laminar flow stage further deformed the fabric stretching it along the flow direction and thus increasing L. The intensity of L is strictly related to the duration and the effect of simple shear (laminar

  19. FABRIC FAULT DETECTION USING IMAGE PROCESSING WITH ATMEL MICROCONTROLLER

    Directory of Open Access Journals (Sweden)

    R.THILEPA,

    2010-11-01

    Full Text Available In this paper it is explained how a faulty fabric image is processed through a microcontroller. If there is any fault how it is identified through this ATMEL microcontroller by the circuit operation. For programming the controller Atmel program is used. In addition to that a stepper motor is connected in the output. This motor operates if there is no fault and fails if the fault is identified. This can be implemented in states like Tamilnadu so that the textile field’s income may be increased in an enormous way which in turn raises the country’s income [7].

  20. A simple cost-effective and eco-friendly wet chemical process for the fabrication of superhydrophobic cotton fabrics

    Energy Technology Data Exchange (ETDEWEB)

    Richard, Edna; Lakshmi, R.V.; Aruna, S.T., E-mail: aruna_reddy@nal.res.in; Basu, Bharathibai J.

    2013-07-15

    Superhydrophobic surfaces were created on hydrophilic cotton fabrics by a simple wet chemical process. The fabric was immersed in a colloidal suspension of zinc hydroxide followed by subsequent hydrophobization with stearic acid. The wettability of the modified cotton fabric sample was studied by water contact angle (WCA) and water shedding angle (WSA) measurements. The modified cotton fabrics exhibited superhydrophobicity with a WCA of 151° for 8 μL water droplet and a WSA of 5–10° for 40 μL water droplet. The superhydrophobic cotton sample was also characterized by field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDX). The method is simple, eco-friendly and cost-effective and can be applied to large area of cotton fabric materials. It was shown that superhydrophobicity of the fabric was due to the combined effect of surface roughness imparted by zinc hydroxide and the low surface energy of stearic acid.

  1. Electrochemical/Pyrometallurgical Waste Stream Processing and Waste Form Fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Steven Frank; Hwan Seo Park; Yung Zun Cho; William Ebert; Brian Riley

    2015-07-01

    This report summarizes treatment and waste form options being evaluated for waste streams resulting from the electrochemical/pyrometallurgical (pyro ) processing of used oxide nuclear fuel. The technologies that are described are South Korean (Republic of Korea – ROK) and United States of America (US) ‘centric’ in the approach to treating pyroprocessing wastes and are based on the decade long collaborations between US and ROK researchers. Some of the general and advanced technologies described in this report will be demonstrated during the Integrated Recycle Test (IRT) to be conducted as a part of the Joint Fuel Cycle Study (JFCS) collaboration between US Department of Energy (DOE) and ROK national laboratories. The JFCS means to specifically address and evaluated the technological, economic, and safe guard issues associated with the treatment of used nuclear fuel by pyroprocessing. The IRT will involve the processing of commercial, used oxide fuel to recover uranium and transuranics. The recovered transuranics will then be fabricated into metallic fuel and irradiated to transmutate, or burn the transuranic elements to shorter lived radionuclides. In addition, the various process streams will be evaluated and tested for fission product removal, electrolytic salt recycle, minimization of actinide loss to waste streams and waste form fabrication and characterization. This report specifically addresses the production and testing of those waste forms to demonstrate their compatibility with treatment options and suitability for disposal.

  2. A Paper on Automatic Fabrics Fault Processing Using Image Processing Technique In MATLAB

    Directory of Open Access Journals (Sweden)

    R.Thilepa

    2011-02-01

    Full Text Available The main objective of this paper is to elaborate how defective fabric parts can beprocessed using Matlab with image processing techniques. In developing countries like Indiaespecially in Tamilnadu, Tirupur the Knitwear capital of the country in three decades yields amajor income for the country. The city also employs either directly or indirectly more than 3lakhs of people and earns almost an income of 12, 000 crores per annum for the country in pastthree decades [2]. To upgrade this process the fabrics when processed in textiles the fault presenton the fabrics can be identified using Matlab with Image processing techniques. This imageprocessing technique is done using Matlab 7.3 and for the taken image, Noise Filtering,Histogram and Thresholding techniques are applied for the image and the output is obtained inthis paper. This research thus implements a textile defect detector with system visionmethodology in image processing.

  3. Atomically Abrupt Topological p-n Junction.

    Science.gov (United States)

    Kim, Sung Hwan; Jin, Kyung-Hwan; Kho, Byung Woo; Park, Byeong-Gyu; Liu, Feng; Kim, Jun Sung; Yeom, Han Woong

    2017-08-24

    Topological insulators (TI's) are a new class of quantum matter with extraordinary surface electronic states, which bear great potential for spintronics and error-tolerant quantum computing. In order to put a TI into any practical use, these materials need to be fabricated into devices whose basic units are often p-n junctions. Interesting electronic properties of a 'topological' p-n junction were proposed theoretically such as the junction electronic state and the spin rectification. However, the fabrication of a lateral topological p-n junction has been challenging because of materials, process, and fundamental reasons. Here, we demonstrate an innovative approach to realize a p-n junction of topological surface states (TSS's) of a three-dimensional (3D) topological insulator (TI) with an atomically abrupt interface. When a ultrathin Sb film is grown on a 3D TI of Bi2Se3 with a typical n-type TSS, the surface develops a strongly p-type TSS through the substantial hybridization between the 2D Sb film and the Bi2Se3 surface. Thus, the Bi2Se3 surface covered partially with Sb films bifurcates into areas of n- and p-type TSS's as separated by atomic step edges with a lateral electronic junction of as short as 2 nm. This approach opens a different avenue toward various electronic and spintronic devices based on well-defined topological p-n junctions with the scalability down to atomic dimensions.

  4. Fabrication of 45 degrees template grain boundary junctions using a CaO lift-off technique

    NARCIS (Netherlands)

    IJsselsteijn, R.P.J.; Terpstra, D.; Flokstra, J.; Rogalla, H.

    1994-01-01

    45 degrees grain boundary junctions have been made using (100) MgO substrates, a CeO2 template layer and an YBa2Cu3O7 top layer. To minimize the damage to the MgO surface, which will occur if the CeO2 is structured using ion milling, the CeO2 layer has been structured using the CaO lift-off techniqu

  5. Flexible aerogel composite for mechanical stability and process of fabrication

    Science.gov (United States)

    Coronado, Paul R.; Poco, John F.

    1999-01-01

    A flexible aerogel and process of fabrication. An aerogel solution is mixed with fibers in a mold and allowed to gel. The gel is then processed by supercritical extraction, or by air drying, to produce a flexible aerogel formed to the shape of the mold. The flexible aerogel has excellent thermal and acoustic properties, and can be utilized in numerous applications, such as for energy absorption, insulation (temperature and acoustic), to meet the contours of aircraft shapes, and where space is limited since an inch of aerogel is a 4-5 times better insulator than an inch of fiberglass. The flexible aerogel may be of an inorganic (silica) type or an organic (carbon) type, but containing fibers, such as glass or carbon fibers.

  6. MOVPE Growth of InxGa1-xN (x ~ 0.4) and Fabrication of Homo-junction Solar Cells

    Institute of Scientific and Technical Information of China (English)

    Md. Rafiqul Islam; Md. Rejvi Kaysir; Md. Jahirul Islam; A. Hashimoto; A. Yamamoto

    2013-01-01

    The metal organic vapor phase epitaxy (MOVPE) growth of indium gallium nitride (InGaN) has been discussed in detail towards the fabrication of solar cell.The InGaN film with In contents up to 0.4 are successfully grown by controlling the fundamental growth parameters such as the precursor gas flow rates,temperature etc.The formation of metallic In originates from the higher value (0.74) of trimethylindium/(trimethylindium + triethylgallium) (TMI/(TMI + TEG)) molar ratio with low (4100) Ⅴ/Ⅲ weight molar ratio while the lower value (0.2) of TMI/(TMI + TEG) causes the phase separation.It is also necessary to control the growth rate and epitaxial film thickness to suppress the phase separation in the material.The crystalline quality of grown films is studied and it is found to be markedly deteriorated with increasing In content.The lattice parameters as well as the thermal expansion coefficient mismatch between GaN template and InGaN epi-layer are primarily considered as the reasons to deteriorate the film quality for higher In content.By using Ino.16Gao.a4N films,an n+-p homo-junction structure is fabricated on 0.65 μm GaN template.For such a device,the response to the light illumination (AM 1.5) is observed with an open circuit voltage of 1.4 V and the short circuit current density of 0.25 mA/cm2.To improve the performance as well as increase solar photon capturing,the device is further fabricated on thick GaN template with higher In content.The Ino.25Gao.75N n+-P junction solar cell is found better performance with an open circuit voltage of 1.5 V and the short circuit current density of 0.5 mA/cm2.This is the InGaN p-n homo-junction solar cell with the highest In content ever reported by MOVPE.

  7. Fabrication and Process Optimization of Super-wettability Metal Mesh

    Directory of Open Access Journals (Sweden)

    CHEN Hong-xia

    2017-09-01

    Full Text Available Super-wettability Cu mesh(200PPI was successfully fabricated by direct oxidation, liquid deposition and vapor deposition in order to expand its application ranges and enhance microstructure effect. The structure, morphology and wettability of Cu mesh were characterized by scanning electron microscopy(SEM, transmission electron microscopy(TEM, X-ray diffraction, contact angle instrument and high speed video, and the optimum preparation process of film layer was obtained. The copper mesh with a layer of knife-like flower film shows super-hydrophilic wettability on which the spread velocity of water is 3.5m/s; moreover, the super-hydrophilic mesh with hybrid structures can be switched into super-hydrophobic material (>150° by liquid deposition and vapor deposition methods; the optimum fabrication conditions to achieve super-hydrophobic performance >150° are oxidation time of 15min, oxidation temperature of 96℃, liquid deposition time of 30min and the treat temperature of 180℃ for 20min. Meantime, hybrid gaps of knife-like flowers are considered as the main reason of the super-wettability of meshes.

  8. Josephson junctions with ferromagnetic interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Wild, Georg Hermann

    2012-03-04

    We report on the fabrication of superconductor/insulator/ferromagnetic metal/superconductor (Nb/AlO{sub x}/Pd{sub 0.82}Ni{sub 0.18}/Nb) Josephson junctions (SIFS JJs) with high critical current densities, large normal resistance times area products, and high quality factors. For these junctions, a transition from 0- to {pi}-coupling is observed for a thickness d{sub F}=6 nm of the ferromagnetic Pd{sub 0.82}Ni{sub 0.18} interlayer. The magnetic field dependence of the critical current of the junctions demonstrates good spatial homogeneity of the tunneling barrier and ferromagnetic interlayer. Magnetic characterization shows that the Pd{sub 0.82}Ni{sub 0.18} has an out-of-plane anisotropy and large saturation magnetization indicating negligible dead layers at the interfaces. A careful analysis of Fiske modes up to about 400 GHz provides valuable information on the junction quality factor and the relevant damping mechanisms. Whereas losses due to quasiparticle tunneling dominate at low frequencies, at high frequencies the damping is explained by the finite surface resistance of the junction electrodes. High quality factors of up to 30 around 200 GHz have been achieved. They allow to study the junction dynamics, in particular the switching probability from the zero-voltage into the voltage state with and without microwave irradiation. The experiments with microwave irradiation are well explained within semi-classical models and numerical simulations. In contrast, at mK temperature the switching dynamics without applied microwaves clearly shows secondary quantum effects. Here, we could observe for the first time macroscopic quantum tunneling in Josephson junctions with a ferromagnetic interlayer. This observation excludes fluctuations of the critical current as a consequence of an unstable magnetic domain structure of the ferromagnetic interlayer and affirms the suitability of SIFS Josephson junctions for quantum information processing.

  9. The performances of silicon solar cell with core-shell p-n junctions of micro-nano pillars fabricated by cesium chloride self-assembly and dry etching

    Science.gov (United States)

    Liu, Jing; Zhang, Xinshuai; Dong, Gangqiang; Liao, Yuanxun; Wang, Bo; Zhang, Tianchong; Yi, Futing

    2014-03-01

    Silicon micro-nano pillars are cost-efficiently integrated using twice cesium chloride (CsCl) islands lithography technique and dry etching for solar cell applications. The micro PMMA islands are fabricated by inductively coupled plasma (ICP) dry etching with micro CsCl islands as masks, and the nano CsCl islands with nano sizes then are made on the surface of micro PMMA islands and silicon. By ICP dry etching with the mask of micro PMMA islands and nano CsCl islands, the micro-nano silicon pillars are made and certain height micro pillars are randomly positioned between dense arrays of nano pillars with different morphologies by controlling etching conditions. With 300 nm depth p-n junction detected by secondary-ion mass spectrometry (SIMS), the micro pillars of the diameter about 1 μm form the core-shell p-n junction to maximize utility of p-n junction interface and enable efficient free carrier collection, and the nano tapered pillars of 150 nm diameter are used to decrease reflection by a graded-refractive-index. Compared to single micro or nano pillar arrayed cells, the co-integrated solar cell with micro and nano pillars demonstrates improved photovoltaic characteristic that is a photovoltaic conversion efficiency (PCE) of 15.35 % with a short circuit current density ( J sc) of 38.40 mA/cm2 and an open circuit voltage ( V oc) of 555.7 mV, which benefits from the advantages of micro-nano pillar structures and can be further improved upon process optimization.

  10. Environmental assessment for radioisotope heat source fuel processing and fabrication

    Energy Technology Data Exchange (ETDEWEB)

    1991-07-01

    DOE has prepared an Environmental Assessment (EA) for radioisotope heat source fuel processing and fabrication involving existing facilities at the Savannah River Site (SRS) near Aiken, South Carolina and the Los Alamos National Laboratory (LANL) near Los Alamos, New Mexico. The proposed action is needed to provide Radioisotope Thermoelectric Generators (RTG) to support the National Aeronautics and Space Administration's (NASA) CRAF and Cassini Missions. Based on the analysis in the EA, DOE has determined that the proposed action does not constitute a major Federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act (NEPA) of 1969. Therefore, an Environmental Impact Statement is not required. 30 refs., 5 figs.

  11. MONOLITHIC FUEL FABRICATION PROCESS DEVELOPMENT AT THE IDAHO NATIONAL LABORATORY_

    Energy Technology Data Exchange (ETDEWEB)

    G. A. Moore; F. J. Rice; N. E. Woolstenhulme; J-F. Jue; B. H. Park; S. E. Steffler; N. P. Hallinan; M. D. Chapple; M. C. Marshall; B. L. Mackowiak; C. R. Clark; B. H. Rabin

    2009-11-01

    Full-size/prototypic U10Mo monolithic fuel-foils and aluminum clad fuel plates are being developed at the Idaho National Laboratory’s (INL) Materials and Fuels Complex (MFC). These efforts are focused on realizing Low Enriched Uranium (LEU) high density monolithic fuel plates for use in High Performance Research and Test Reactors. The U10Mo fuel foils under development afford a fuel meat density of ~16 gU/cc and thus have the potential to facilitate LEU conversions without any significant reactor-performance penalty. An overview is provided of the ongoing monolithic UMo fuel development effort, including application of a zirconium barrier layer on fuel foils, fabrication scale-up efforts, and development of complex/graded fuel foils. Fuel plate clad bonding processes to be discussed include: Hot Isostatic Pressing (HIP) and Friction Bonding (FB).

  12. A Novel Method to Fabricate Silicon Nanowire p–n Junctions by a Combination of Ion Implantation and in-situ Doping

    Directory of Open Access Journals (Sweden)

    Kögler Reinhard

    2009-01-01

    Full Text Available Abstract We demonstrate a novel method to fabricate an axial p–n junction inside <111> oriented short vertical silicon nanowires grown by molecular beam epitaxy by combining ion implantation with in-situ doping. The lower halves of the nanowires were doped in-situ with boron (concentration ~1018cm−3, while the upper halves were doubly implanted with phosphorus to yield a uniform concentration of 2 × 1019 cm−3. Electrical measurements of individually contacted nanowires showed excellent diode characteristics and ideality factors close to 2. We think that this value of ideality factors arises out of a high rate of carrier recombination through surface states in the native oxide covering the nanowires.

  13. 3D Printed Surgical Instruments: The Design and Fabrication Process.

    Science.gov (United States)

    George, Mitchell; Aroom, Kevin R; Hawes, Harvey G; Gill, Brijesh S; Love, Joseph

    2017-01-01

    3D printing is an additive manufacturing process allowing the creation of solid objects directly from a digital file. We believe recent advances in additive manufacturing may be applicable to surgical instrument design. This study investigates the feasibility, design and fabrication process of usable 3D printed surgical instruments. The computer-aided design package SolidWorks (Dassault Systemes SolidWorks Corp., Waltham MA) was used to design a surgical set including hemostats, needle driver, scalpel handle, retractors and forceps. These designs were then printed on a selective laser sintering (SLS) Sinterstation HiQ (3D Systems, Rock Hill SC) using DuraForm EX plastic. The final printed products were evaluated by practicing general surgeons for ergonomic functionality and performance, this included simulated surgery and inguinal hernia repairs on human cadavers. Improvements were identified and addressed by adjusting design and build metrics. Repeated manufacturing processes and redesigns led to the creation of multiple functional and fully reproducible surgical sets utilizing the user feedback of surgeons. Iterative cycles including design, production and testing took an average of 3 days. Each surgical set was built using the SLS Sinterstation HiQ with an average build time of 6 h per set. Functional 3D printed surgical instruments are feasible. Advantages compared to traditional manufacturing methods include no increase in cost for increased complexity, accelerated design to production times and surgeon specific modifications.

  14. Fabrication Process Development for Light Deformable Mirrors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This development is a collaborative effort between California Institute of Technology (Caltech) and the Jet Propulsion Laboratory (JPL). The fabrication is done...

  15. Advanced materials and fabrication processes for supersonic cruise aircraft

    Science.gov (United States)

    Guess, M. K.; Kaneko, R. S.; Wald, G. G.

    1981-01-01

    Research and development programs to develop high-strength aluminum alloys and low-cost materials and fabrication techniques for titanium alloys are being conducted. Thirteen aluminum alloy compositions are being evaluated. A section of a production component was fabricated using superplastic forming and diffusion bonding (SPF/DB) and fabrication studies are being conducted on three low temperature forming beta titanium alloys. Cost studies indicate substantial structural cost reduction potentials resulting from the use of both aluminum alloys and low-cost titanium fabrication techniques. Lowest overall costs are indicated for a composite/aluminum or composite titanium structure.

  16. Processing and fabrication of high temperature oxide superconductors

    Science.gov (United States)

    Johnson, Sylvia M.

    1989-07-01

    During the past year, a process for synthesizing superconductor powders by freeze drying was optimized. The objectives were to develop an understanding of the processing of these powders and to fabricate simple shapes from freeze dried powders. A series of powders were synthesized from solutions of barium acetate, copper nitrate, and yttrium nitrate, with pH values of 2.8 to 9.8 and calcined at temperatures from 510 to 908 C. The surface area of these powders were determined by BET AND XRD. Selected powders are being characterized by SEM, DTA, ICP analysis (performed at Stanford University), carbon analysis, and tap density. The highest surface area (in lightly milled powders) of 4.4 sq m/g was achieved with a pH of 4 in a series of experiments in which the Ba and Y solutions were mixed together before the Cu nitrate solution was added, then calcined at 825 C. Surface areas decrease with increasing calcining temperature, however. It appears that calcining at 750 or 850 C gives the best critical temperature, with complete transitions at greater than 90 K. Critical temperature measurements performed at Standford show that the goal of a critical temperature of Tc greater than 90 K and a temperature difference, W, between 10 and 90 percent of transition of less than 2 K, were achieved.

  17. Wideband polarization splitter and rotator with large fabrication tolerance and simple fabrication process

    DEFF Research Database (Denmark)

    Ding, Yunhong; Ou, Haiyan; Peucheret, Christophe

    2013-01-01

    We propose and demonstrate a polarization splitter and rotator (PSR) built on a silicon-on-insulator platform. The PSR is constructed with a tapered waveguide followed by a 2×2 multimode interferometer and can be simply fabricated in a single lithography and etching step. A low insertion loss (....5  dB with minimum insertion loss of 0.6 dB) and a low polarization crosstalk (fabrication tolerance (>50  nm) are experimentally demonstrated....

  18. Fabrication

    Directory of Open Access Journals (Sweden)

    E.M.S. Azzam

    2013-12-01

    Full Text Available In the present work, the nanoclay composites were fabricated using the synthesized poly 6-(3-aminophenoxy hexane-1-thiol, poly 8-(3-aminophenoxy octane-1-thiol and poly 10-(3-aminophenoxy decane-1-thiol surfactants with gold nanoparticles. The polymeric thiol surfactants were first assembled on gold nanoparticles and then impregnated into the clay matrix. Different spectroscopic and microscopic techniques such as X-ray diffraction (XRD, Scanning electron microscope (SEM and Transmission microscope (TEM were used to characterize the fabricated nanoclay composites. The results showed that the polymeric thiol surfactants assembled on gold nanoparticles are located in the interlayer space of the clay mineral and affected the clay structure.

  19. Silicon fiber with p-n junction

    Energy Technology Data Exchange (ETDEWEB)

    Homa, D.; Cito, A.; Pickrell, G.; Hill, C.; Scott, B. [Department of Materials Science and Engineering, Virginia Polytechnic Institute and State University, 312 Holden Hall, Blacksburg, Virginia 24060 (United States)

    2014-09-22

    In this study, we fabricated a p-n junction in a fiber with a phosphorous doped silicon core and fused silica cladding. The fibers were fabricated via a hybrid process of the core-suction and melt-draw techniques and maintained overall diameters ranging from 200 to 900 μm and core diameters of 20–800 μm. The p-n junction was formed by doping the fiber with boron and confirmed via the current-voltage characteristic. The demonstration of a p-n junction in a melt-drawn silicon core fiber paves the way for the seamless integration of optical and electronic devices in fibers.

  20. Finite Element Models for Electron Beam Freeform Fabrication Process

    Science.gov (United States)

    Chandra, Umesh

    2012-01-01

    Electron beam freeform fabrication (EBF3) is a member of an emerging class of direct manufacturing processes known as solid freeform fabrication (SFF); another member of the class is the laser deposition process. Successful application of the EBF3 process requires precise control of a number of process parameters such as the EB power, speed, and metal feed rate in order to ensure thermal management; good fusion between the substrate and the first layer and between successive layers; minimize part distortion and residual stresses; and control the microstructure of the finished product. This is the only effort thus far that has addressed computer simulation of the EBF3 process. The models developed in this effort can assist in reducing the number of trials in the laboratory or on the shop floor while making high-quality parts. With some modifications, their use can be further extended to the simulation of laser, TIG (tungsten inert gas), and other deposition processes. A solid mechanics-based finite element code, ABAQUS, was chosen as the primary engine in developing these models whereas a computational fluid dynamics (CFD) code, Fluent, was used in a support role. Several innovative concepts were developed, some of which are highlighted below. These concepts were implemented in a number of new computer models either in the form of stand-alone programs or as user subroutines for ABAQUS and Fluent codes. A database of thermo-physical, mechanical, fluid, and metallurgical properties of stainless steel 304 was developed. Computing models for Gaussian and raster modes of the electron beam heat input were developed. Also, new schemes were devised to account for the heat sink effect during the deposition process. These innovations, and others, lead to improved models for thermal management and prediction of transient/residual stresses and distortions. Two approaches for the prediction of microstructure were pursued. The first was an empirical approach involving the

  1. LAF-Fabric : Data processing for Linguistic Annotation Framework

    NARCIS (Netherlands)

    Roorda, Dirk

    2014-01-01

    LAF-fabric is a Python tool for running Python notebooks with access to the information in a LAF resource. The selling point of LAF-fabric is performance, both in terms of speed and memory usage. The second goal is to make it really easy for you to write analytic notebooks straightforwardly in terms

  2. LAF-Fabric : Data processing for Linguistic Annotation Framework

    NARCIS (Netherlands)

    Roorda, Dirk

    2014-01-01

    LAF-fabric is a Python tool for running Python notebooks with access to the information in a LAF resource. The selling point of LAF-fabric is performance, both in terms of speed and memory usage. The second goal is to make it really easy for you to write analytic notebooks straightforwardly in terms

  3. Two Distinct MUS81-EME1 Complexes from Arabidopsis Process Holliday Junctions1[W

    Science.gov (United States)

    Geuting, Verena; Kobbe, Daniela; Hartung, Frank; Dürr, Jasmin; Focke, Manfred; Puchta, Holger

    2009-01-01

    The MUS81 endonuclease complex has been shown to play an important role in the repair of stalled or blocked replication forks and in the processing of meiotic recombination intermediates from yeast to humans. This endonuclease is composed of two subunits, MUS81 and EME1. Surprisingly, unlike other organisms, Arabidopsis (Arabidopsis thaliana) has two EME1 homologs encoded in its genome. AtEME1A and AtEME1B show 63% identity on the protein level. We were able to demonstrate that, after expression in Escherichia coli, each EME1 protein can assemble with the unique AtMUS81 to form a functional endonuclease. Both complexes, AtMUS81-AtEME1A and AtMUS81-AtEME1B, are not only able to cleave 3′-flap structures and nicked Holliday junctions (HJs) but also, with reduced efficiency, intact HJs. While the complexes have the same cleavage patterns with both nicked DNA substrates, slight differences in the processing of intact HJs can be detected. Our results are in line with an involvement of both MUS81-EME1 endonuclease complexes in DNA recombination and repair processes in Arabidopsis. PMID:19339504

  4. Two distinct MUS81-EME1 complexes from Arabidopsis process Holliday junctions.

    Science.gov (United States)

    Geuting, Verena; Kobbe, Daniela; Hartung, Frank; Dürr, Jasmin; Focke, Manfred; Puchta, Holger

    2009-06-01

    The MUS81 endonuclease complex has been shown to play an important role in the repair of stalled or blocked replication forks and in the processing of meiotic recombination intermediates from yeast to humans. This endonuclease is composed of two subunits, MUS81 and EME1. Surprisingly, unlike other organisms, Arabidopsis (Arabidopsis thaliana) has two EME1 homologs encoded in its genome. AtEME1A and AtEME1B show 63% identity on the protein level. We were able to demonstrate that, after expression in Escherichia coli, each EME1 protein can assemble with the unique AtMUS81 to form a functional endonuclease. Both complexes, AtMUS81-AtEME1A and AtMUS81-AtEME1B, are not only able to cleave 3'-flap structures and nicked Holliday junctions (HJs) but also, with reduced efficiency, intact HJs. While the complexes have the same cleavage patterns with both nicked DNA substrates, slight differences in the processing of intact HJs can be detected. Our results are in line with an involvement of both MUS81-EME1 endonuclease complexes in DNA recombination and repair processes in Arabidopsis.

  5. Silver-clad ? superconducting tapes fabricated by different mechanical processing

    Science.gov (United States)

    Guo, Y. C.; Liu, H. K.; Dou, S. X.; Kuroda, T.; Tanaka, Y.

    1998-10-01

    0953-2048/11/10/032/img10/silver composites were fabricated by drawing a silver tube packed with precursor powders into round wire and deforming the round wire into flat tapes by longitudinal rolling, transverse rolling and uniaxial pressing respectively. The resultant tapes were observed by optical microscopy to examine the superconductor core/silver interface. Short pieces were cut from the tapes and heat-treated by a thermomechanical process consisting of alternate sintering and intermediate mechanical deformation. Intermediate deformation was carried out for each tape using the method by which the tape was formed. The effect of different deformations on the microstructure and transport property of the final tapes was investigated. It was found that deformation method affected the core/silver interface of tapes significantly. Pressing produced a wavier core/silver interface (sausaging) and more cracks than longitudinal and transverse rolling. As for critical current density, pressing yielded the highest value, due to the higher density and better grain alignment in the pressed tapes than in the longitudinal and transverse rolled ones.

  6. Fabrication of L1{sub 0}-MnAl perpendicularly magnetized thin films for perpendicular magnetic tunnel junctions

    Energy Technology Data Exchange (ETDEWEB)

    Hosoda, Masaki; Oogane, Mikihiko; Kubota, Miho; Saruyama, Haruaki; Iihama, Satoshi; Naganuma, Hiroshi; Ando, Yasuo [Department of Applied Physics, Graduate school of Engineering, Tohoku University, Aza-aoba 6-6-05, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Kubota, Takahide [WPI Advanced Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577 (Japan)

    2012-04-01

    Structural and magnetic properties of MnAl thin films with different composition, growth temperature, and post-annealing temperature were investigated. The optimum condition for fabrication of L1{sub 0}-MnAl perpendicularly magnetized thin film deposited on Cr-buffered MgO single crystal substrate was revealed. The results of x ray diffraction indicated that the MnAl films annealed at proper temperature had a (001)-orientation and L1{sub 0}-ordered structure. The L1{sub 0}-ordered films were perpendicularly magnetized and had a large perpendicular anisotropy. In addition, low surface roughness was achieved. For the optimized fabrication condition, the saturation magnetization M{sub s} of 600 emu/cm{sup 3} and perpendicular magnetic anisotropy K{sub u} of 1.0 x 10{sup 7} erg/cm{sup 3} was obtained using the Mn{sub 48}Al{sub 52} target at deposition temperature of 200 deg. C and post-annealing temperature of 450 deg. C.

  7. Submicron area NbN/MgO/NbN tunnel junctions for SIS mixer applications

    Science.gov (United States)

    Leduc, H. G.; Judas, A.; Cypher, S. R.; Bumble, B.; Hunt, B. D.

    1991-01-01

    The development of submicron area mixer elements for operation in the submillimeter wave range is discussed. High-current-density NbN/MgO/NbN tunnel junctions with areas down to 0.1 sq microns have been fabricated in both planar and edge geometries. The planar junctions were fabricated from in situ deposited trilayers using electron-beam lithography to pattern submicron area mesas. Modifications of fabrication techniques used in larger-area NbN tunnel junctions are required and are discussed. The NbN/MgO/NbN edge junction process using sapphire substrates has been transferred to technologically important quartz substrates using MgO buffer layers to minimize substrate interactions. The two junction geometries are compared and contrasted in the context of submillimeter wave mixer applications.

  8. Vertical current-flow enhancement via fabrication of GaN nanorod p-n junction diode on graphene

    Science.gov (United States)

    Ryu, Sung Ryong; Ram, S. D. Gopal; Lee, Seung Joo; Cho, Hak-dong; Lee, Sejoon; Kang, Tae Won; Kwon, Sangwoo; Yang, Woochul; Shin, Sunhye; Woo, Yongdeuk

    2015-08-01

    Mg doped GaN nanorods were grown on undoped n-type GaN nanorods uniaxial on monolayer graphene by hydride vapor phase epitaxy (HVPE) method. The monolayer graphene used as the bottom electrode and a substrate as well provides good electrical contact, acts as a current spreading layer, well suitable for the growth of hexagonal GaN nanorod. In addition it has a work function suitable to that of n-GaN. The formed p-n nanorods show a Schottky behavior with a turn on voltage of 3 V. Using graphene as the substrate, the resistance of the nanorod is reduced by 700 times when compared with the case without using graphene as the current spreading layer. The low resistance of graphene acts in parallel with the resistance of the GaN buffer layer, and reduces the resistance drastically. The formed p-n junction in a single GaN nanorod is visualized by Kelvin Force Probe Microscopy (KPFM) to have distinctively contrast p and n regions. The measured contact potential difference of p-and n-region has a difference of 103 mV which well confirms the formed regions are electronically different. Low temperature photoluminescence (PL) spectra give evidence of dopant related acceptor bound emission at 3.2 eV different from 3.4 eV of undoped GaN. The crystalline structure, compositional purity is confirmed by X-ray diffraction (XRD), Transmission and Scanning electron microcopies (SEM), (TEM), Energy dispersive analysis by X-ray (EDAX) and X-ray photoelectron spectroscopy (XPS) as well.

  9. Multi-Step Deep Reactive Ion Etching Fabrication Process for Silicon-Based Terahertz Components

    Science.gov (United States)

    Jung-Kubiak, Cecile (Inventor); Reck, Theodore (Inventor); Chattopadhyay, Goutam (Inventor); Perez, Jose Vicente Siles (Inventor); Lin, Robert H. (Inventor); Mehdi, Imran (Inventor); Lee, Choonsup (Inventor); Cooper, Ken B. (Inventor); Peralta, Alejandro (Inventor)

    2016-01-01

    A multi-step silicon etching process has been developed to fabricate silicon-based terahertz (THz) waveguide components. This technique provides precise dimensional control across multiple etch depths with batch processing capabilities. Nonlinear and passive components such as mixers and multipliers waveguides, hybrids, OMTs and twists have been fabricated and integrated into a small silicon package. This fabrication technique enables a wafer-stacking architecture to provide ultra-compact multi-pixel receiver front-ends in the THz range.

  10. Ship-in-a-Bottle Biomicrochips Fabricated by Hybrid Femtosecond Laser Processing

    Directory of Open Access Journals (Sweden)

    Sugioka Koji

    2013-11-01

    Full Text Available We demonstrate fabrication of highly functional biomicrochips by hybrid femtosecond laser processing. In this process, 3D microfluidic structures are first formed inside photosensitive glass by femtosecond laser direct writing followed by thermal treatment and successive chemical wet etching. Then, functional microcomponents are integrated inside the fabricated microfluidic structures by two-photon photopolyerization. We term the fabricated microchips ship-in-a-bottle biomicrochips,

  11. Speed distributions at a controlled junction using microscopic real data from image processing

    NARCIS (Netherlands)

    Wilmink, I.R.; Arem, B. van

    2008-01-01

    Modeling realistic driving behavior at signalized junctions is fundamental for many applications, for instance for determining the signal capacity or for estimating traffic emissions. For these measures, the knowledge of speed, acceleration and deceleration of individual vehicles passing the signal

  12. Speed distributions at a controlled junction using microscopic real data from image processing

    NARCIS (Netherlands)

    Wilmink, I.R.; Arem, B. van

    2008-01-01

    Modeling realistic driving behavior at signalized junctions is fundamental for many applications, for instance for determining the signal capacity or for estimating traffic emissions. For these measures, the knowledge of speed, acceleration and deceleration of individual vehicles passing the signal

  13. Application of foams to the processing of fabrics. Final report, October 1, 1977-September 30, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Namboodri, C.G.

    1981-10-01

    The primary objective of this project was to reduce the energy consumed in the wet processing of fabrics where wet processing encompasses those processes used to convert loomstate (greige) goods to finished textile products. This includes desizing, scouring, bleaching, dyeing, printing, and finishing of fabrics. The energy intensive step in most of these processes is drying the fabric. By having less water on the fabric as it enters a drying oven, proportionately less energy is consumed in drying the fabric. The specific route used in this project to accomplish this objective has been to use air to distribute the finish, dye or printing ink onto the fabric. Rather than saturating the fabric with a dilute finish formulation, a concentrated formulation is mechanically foamed, air serving as the diluting medium and the foam applied to the fabric. In this manner, the water content of the fabric as it enters the drying oven is reduced by as much as 80% thereby leading to a corresponding reduction in the energy required to dry the fabric. Details on the procedure are presented and experimental results are discussed. (MCW)

  14. Plasma Separation Process: Betacell (BCELL) code: User's manual. [Bipolar barrier junction

    Energy Technology Data Exchange (ETDEWEB)

    Taherzadeh, M.

    1987-11-13

    The emergence of clearly defined applications for (small or large) amounts of long-life and reliable power sources has given the design and production of betavoltaic systems a new life. Moreover, because of the availability of the plasma separation program, (PSP) at TRW, it is now possible to separate the most desirable radioisotopes for betacell power generating devices. A computer code, named BCELL, has been developed to model the betavoltaic concept by utilizing the available up-to-date source/cell parameters. In this program, attempts have been made to determine the betacell energy device maximum efficiency, degradation due to the emitting source radiation and source/cell lifetime power reduction processes. Additionally, comparison is made between the Schottky and PN junction devices for betacell battery design purposes. Certain computer code runs have been made to determine the JV distribution function and the upper limit of the betacell generated power for specified energy sources. A Ni beta emitting radioisotope was used for the energy source and certain semiconductors were used for the converter subsystem of the betacell system. Some results for a Promethium source are also given here for comparison. 16 refs.

  15. Electrochromic Windows: Process and Fabrication Improvements for Lower Total Costs

    Energy Technology Data Exchange (ETDEWEB)

    Mark Burdis; Neil Sbar

    2007-03-31

    The overall goal with respect to the U.S. Department of Energy (DOE) is to achieve significant national energy savings through maximized penetration of EC windows into existing markets so that the largest cumulative energy reduction can be realized. The speed with which EC windows can be introduced and replace current IGU's (and current glazings) is clearly a strong function of cost. Therefore, the aim of this project was to investigate possible improvements to the SageGlass{reg_sign} EC glazing products to facilitate both process and fabrication improvements resulting in lower overall costs. The project was split into four major areas dealing with improvements to the electrochromic layer, the capping layer, defect elimination and general product improvements. Significant advancements have been made in each of the four areas. These can be summarized as follows: (1) Plasma assisted deposition for the electrochromic layer was pursued, and several improvements made to the technology for producing a plasma beam were made. Functional EC devices were produced using the new technology, but there are still questions to be answered regarding the intrinsic properties of the electrochromic films produced by this method. (2) The capping layer work was successfully implemented into the existing SageGlass{reg_sign} product, thereby providing a higher level of transparency and somewhat lower reflectivity than the 'standard' product. (3) Defect elimination is an ongoing effort, but this project spurred some major defect reduction programs, which led to significant improvements in yield, with all the implicit benefits afforded. In particular, major advances were made in the development of a new bus bar application process aimed at reducing the numbers of 'shorts' developed in the finished product, as well as making dramatic improvements in the methods used for tempering the glass, which had previously been seen to produce a defect which appeared as a

  16. High density processing electronics for superconducting tunnel junction x-ray detector arrays

    Energy Technology Data Exchange (ETDEWEB)

    Warburton, W.K., E-mail: bill@xia.com [XIA LLC, 31057 Genstar Road, Hayward, CA 94544 (United States); Harris, J.T. [XIA LLC, 31057 Genstar Road, Hayward, CA 94544 (United States); Friedrich, S. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States)

    2015-06-01

    Superconducting tunnel junctions (STJs) are excellent soft x-ray (100–2000 eV) detectors, particularly for synchrotron applications, because of their ability to obtain energy resolutions below 10 eV at count rates approaching 10 kcps. In order to achieve useful solid detection angles with these very small detectors, they are typically deployed in large arrays – currently with 100+ elements, but with 1000 elements being contemplated. In this paper we review a 5-year effort to develop compact, computer controlled low-noise processing electronics for STJ detector arrays, focusing on the major issues encountered and our solutions to them. Of particular interest are our preamplifier design, which can set the STJ operating points under computer control and achieve 2.7 eV energy resolution; our low noise power supply, which produces only 2 nV/√Hz noise at the preamplifier's critical cascode node; our digital processing card that digitizes and digitally processes 32 channels; and an STJ I–V curve scanning algorithm that computes noise as a function of offset voltage, allowing an optimum operating point to be easily selected. With 32 preamplifiers laid out on a custom 3U EuroCard, and the 32 channel digital card in a 3U PXI card format, electronics for a 128 channel array occupy only two small chassis, each the size of a National Instruments 5-slot PXI crate, and allow full array control with simple extensions of existing beam line data collection packages.

  17. Self-Assembly Assisted Fabrication of Dextran-Based Nanohydrogels with Reduction-Cleavable Junctions for Applications as Efficient Drug Delivery Systems

    Science.gov (United States)

    Wang, Hao; Dai, Tingting; Zhou, Shuyan; Huang, Xiaoxiao; Li, Songying; Sun, Kang; Zhou, Guangdong; Dou, Hongjing

    2017-01-01

    In order to overcome the key challenge in improving both fabrication efficiency and their drug delivery capability of anti-cancer drug delivery systems (ACDDS), here polyacrylic acid (PAA) grafted dextran (Dex) nanohydrogels (NGs) with covalent crosslinked structure bearing redox sensitive disulfide crosslinking junctions (Dex-SS-PAA) were synthesized efficiently through a one-step self-assembly assisted methodology (SAA). The Dex-SS-PAA were subsequently conjugated with doxorubicin through an acid-labile hydrazone bond (Dex-SS-PAA-DOX). The in vitro drug release behavior, anti-cancer effects in vivo, and biosafety of the as-prepared acid- and redox-dual responsive biodegradable NGs were systematically investigated. The results revealed that the Dex-SS-PAA-DOX exhibited pH- and redox-controlled drug release, greatly reduced the toxicity of free DOX, while exhibiting a strong ability to inhibit the growth of MDA-MB-231 tumors. Our study demonstrated that the Dex-SS-PAA-DOX NGs are very promising candidates as ACDDS for anti-cancer therapeutics.

  18. Study the Characteristic of P-Type Junction-Less Side Gate Silicon Nanowire Transistor Fabricated by Atomic Force Microscopy Lithography

    Directory of Open Access Journals (Sweden)

    Arash Dehzangi

    2011-01-01

    Full Text Available Problem statement: Nanotransistor now is one of the most promising fields in nanoelectronics in order to decrease the energy consuming and application to create developed programmable information processors. Most of Computing and communications companies invest hundreds of millions of dollars in research funds every year to develop smaller transistors. Approach: The Junction-less side gate silicon Nano-wire transistor has been fabricated by Atomic Force Microscopy (AFM and wet etching on p-type Silicon On Insulator (SOI wafer. Then, we checked the characteristic and conductance trend in this device regarding to semi-classical approach by Semiconductor Probe Analyser (SPA. Results: We observed in characteristic of the device directly proportionality of the negative gate voltage and Source-Drain current. In semi classical approach, negative Gate voltage decreased the energy States of the Nano-wire between the source and the drain. The graph for positive gate voltage plotted as well to check. In other hand, the conductance will be following characteristic due to varying the gate voltage under the different drain-source voltage. Conclusion: The channel energy states are supposed to locate between two electrochemical potentials of the contacts in order to transform the charge. For the p-type channel the transform of the carriers is located in valence band and changing the positive or negative gate voltage, making the valence band energy states out of or in the area between the electrochemical potentials of the contacts causing the current reduced or increased.

  19. Development and demonstration of manufacturing processes for fabricating graphite/LARC 160 polyimide structural elements

    Science.gov (United States)

    Frost, R. K.; Jones, J. S.; Dynes, P. J.; Wykes, D. H.

    1981-01-01

    The development and demonstration of manufacturing technologies for the structural application of Celion graphite/LARC-160 polyimide composite material is discussed. Process development and fabrication of demonstration components are discussed. Process development included establishing quality assurance of the basic composite material and processing, nondestructive inspection of fabricated components, developing processes for specific structural forms, and qualification of processes through mechanical testing. Demonstration components were fabricated. The demonstration components consisted of flat laminates, skin/stringer panels, honeycomb panels, chopped fiber compression moldings, and a technology demonstrator segment (TDS) representative of the space shuttle aft body flap.

  20. Design and fabrication of wraparound contact silicon solar cells

    Science.gov (United States)

    Scott-Monck, J. A.; Stella, P. M.; Avery, J. E.

    1972-01-01

    Both dielectric insulation and etched junction contact techniques were evaluated for use in wraparound contact cell fabrication. Since a suitable process for depositing the dielectrics was not achieved, the latter approach was taken. The relationship between loss of back contact and power degradation due to increased series resistance was established and used to design a simple contact configuration for 10 ohm-cm etched wraparound junction contact N/P cells. A slightly deeper junction significantly improved cell curve shape and the associated loss of current was regained by using thinner contact grid fingers. One thousand cells with efficiencies greater than 10.5% were fabricated to demonstrate the process.

  1. Development of Co-Sintering Process for Effective Fabrication of Direct-Write Planer Waveguide

    Institute of Scientific and Technical Information of China (English)

    W.Jung; S.; Yoo; S.; Boo; U.-C.; Paek; W.-T.; Han

    2003-01-01

    We propose a co-sintering process for effective fabrication of three-layered structure for direct-write planar waveguide. Processing parameters and optical properties of the waveguide was investigated.

  2. A new fabrication process for the SOI-based miniature electric field sensor

    Institute of Scientific and Technical Information of China (English)

    Liu Wei; Yang Pengfei; Peng Chunrong; Fang Dongming; Xia Shanhong

    2013-01-01

    This paper presents a new fabrication process for the SOI-based novel miniature electric field sensor.This new process uses polyimide film to release the SiO2 layer.Compared with the CO2 critical point release method,it significantly improves the device surface cleanliness and shortens the process flow.The impurity on the base layer is analyzed.The problem of peak and butterfly-type contamination occurring on the base layer of the SOI wafer during the DRIE process is discussed and solved by thickening the photoresist layer and coating with polyimide film twice.This new process could fabricate MEMS sensors and actuators such as SOI-based electric field sensors,gyroscopes,and micro mirrors and can be an alternative fabrication process compared to commercial SOIMUMPS fabrication processes.

  3. Manufacturing processes for fabricating graphite/PMR 15 polyimide structural elements

    Science.gov (United States)

    Sheppard, C. H.; Hoggatt, J. T.; Symonds, W. A.

    1979-01-01

    Investigations were conducted to obtain commercially available graphite/PMR-15 polyimide prepreg, develop an autoclave manufacturing process, and demonstrate the process by manufacturing structural elements. Controls were established on polymer, prepreg, composite fabrication, and quality assurance, Successful material quality control and processes were demonstrated by fabricating major structural elements including flat laminates, hat sections, I beam sections, honeycomb sandwich structures, and molded graphite reinforced fittings. Successful fabrication of structural elements and simulated section of the space shuttle aft body flap shows that the graphite/PMR-15 polyimide system and the developed processes are ready for further evaluation in flight test hardware.

  4. Modelling, analysis, and acceleration of a printed circuit board fabrication process

    Indian Academy of Sciences (India)

    K S Aithal; Y Narahari; E Manjunath

    2001-10-01

    Product design and fabrication constitute an important business activity in any manufacturing firm. Designing an optimized product fabrication process is an important problem in itself and is of significant practical and research interest. In this paper, we look into a printed circuit board (PCB) fabrication process and investigate ways in which the fabrication cycle time can be minimized. Single class queueing networks constitute the modelling framework for our study. The model developed in this paper and the analysis experiments carried out are based on extensive data collected on a PCB fabrication company located in Bangalore, India. This is a representative PCB fabrication company involving multiple, concurrent fabrication works with contention for human/technical resources. Our model seeks to capture faithfully the flow of the fabrication process in this company and such other organisations, using queueing networks. Using the model developed, we explore how the cycle times can be reduced using input control, load balancing, and variability reduction. The model presented is sufficiently generic and conceptual; its scope extends beyond that of a PCB fabrication organization.

  5. Novel magnetic wire fabrication process by way of nanoimprint lithography for current induced magnetization switching

    Directory of Open Access Journals (Sweden)

    Tsukasa Asari

    2017-05-01

    Full Text Available Nanoimprint lithography (NIL is an effective method to fabricate nanowire because it does not need expensive systems and this process is easier than conventional processes. In this letter, we report the Current Induced Magnetization Switching (CIMS in perpendicularly magnetized Tb-Co alloy nanowire fabricated by NIL. The CIMS in Tb-Co alloy wire was observed by using current pulse under in-plane external magnetic field (HL. We successfully observed the CIMS in Tb-Co wire fabricated by NIL. Additionally, we found that the critical current density (Jc for the CIMS in the Tb-Co wire fabricated by NIL is 4 times smaller than that fabricated by conventional lift-off process under HL = 200Oe. These results indicate that the NIL is effective method for the CIMS.

  6. Process development and fabrication for sphere-pac fuel rods. [PWR; BWR

    Energy Technology Data Exchange (ETDEWEB)

    Welty, R.K.; Campbell, M.H.

    1981-06-01

    Uranium fuel rods containing sphere-pac fuel have been fabricated for in-reactor tests and demonstrations. A process for the development, qualification, and fabrication of acceptable sphere-pac fuel rods is described. Special equipment to control fuel contamination with moisture or air and the equipment layout needed for rod fabrication is described and tests for assuring the uniformity of the fuel column are discussed. Fuel retainers required for sphere-pac fuel column stability and instrumentation to measure fuel column smear density are described. Results of sphere-pac fuel rod fabrication campaigns are reviewed and recommended improvements for high throughput production are noted.

  7. Top contact organic field effect transistors fabricated using a photolithographic process

    Institute of Scientific and Technical Information of China (English)

    Wang Hong; Ji zhuo-Yu; Shang Li-Wei; Liu Xing-Hua; Peng Ying-Quan; Liu Ming

    2011-01-01

    This paper proposes an effective method of fabricating top contact organic field effect transistors by using a photolithographic process.The semiconductor layer is protected by a passivation layer.Through photolithographic and etching processes,parts of the passivation layer are etched off to form source/drain electrode patterns.Combined with conventional evaporation and lift-off techniques,organic field effect transistors with a top contact are fabricated successfully,whose properties are comparable to those prepared with the shadow mask method and one order of magnitude higher than the bottom contact devices fabricated by using a photolithographic process.

  8. High performance mask fabrication process for the next-generation mask production

    Science.gov (United States)

    Yagawa, Keisuke; Ugajin, Kunihiro; Suenaga, Machiko; Kobayashi, Yoshihito; Motokawa, Takeharu; Hagihara, Kazuki; Saito, Masato; Itoh, Masamitsu

    2014-07-01

    ArF immersion lithography combined with double patterning has been used for fabricating below half pitch 40nm devices. However, when pattern size shrinks below 20nm, we must use new technology like quadruple patterning process or next generation lithography (NGL) solutions. Moreover, with change in lithography tool, next generation mask production will be needed. According to ITRS 2013, fabrication of finer patterns less than 15nm will be required on mask plate in NGL mask production 5 years later [1]. In order to fabricate finer patterns on mask, higher resolution EB mask writer and high performance fabrication process will be required. In a previous study, we investigated a potential of mask fabrication process for finer patterning and achieved 17nm dense line pattern on mask plate by using VSB (Variable Shaped Beam) type EB mask writer and chemically amplified resist [2][3]. After a further investigation, we constructed higher performance mask process by using new EB mask writer EBM9000. EBM9000 is the equipment supporting hp16nm generation's photomask production and has high accuracy and high throughput. As a result, we achieved 15.5nm pattern on mask with high productivity. Moreover, from evaluation of isolated pattern, we proved that current mask process has the capability for sub-10nm pattern. These results show that the performance of current mask fabrication process have the potential to fabricate the next-generation mask.

  9. Analysis of the turn-on process in 6 kV 4H-SiC junction diodes

    Science.gov (United States)

    Mnatsakanov, T. T.; Levinshtein, M. E.; Ivanov, P. A.; Palmour, J. W.; Das, M.; Agarwal, A. K.

    2005-01-01

    The switch-on process in 6 kV 4H-SiC junction diodes has been investigated experimentally and theoretically. The results of a detailed computer simulation are compared with the data furnished by the analytical theory. It is demonstrated that, at high current densities exceeding the critical value jcr = eNDvs (e is the elementary charge, ND is the base doping level, and vs is the carrier saturation velocity) and rather short current rise time (1 ns), an extremely fast base modulation can be achieved. In this mode, the base is spanned by an electron front that moves from the n+-n to the p+-n emitter with a velocity vs and by a relatively slow quasi-neutral hole front moving in the opposite direction, from the p+-n to the n+-n junction.

  10. Research on tensile fracture process of polyester woven fabric based on AE technique and HHT

    Directory of Open Access Journals (Sweden)

    Yajing XUE

    2016-10-01

    Full Text Available In order to obtain and study time-frequency characteristics of fabric tensile failure modes, four kinds of fabrics is woven with changing different fabric organizational structures and weft densities, dynamic audio signals for different fabrics in tensile failure process is collected with the aid of self-built acoustic emission detection system on the conventional fabric tensile tester, and the collected signal is analyzed and processed by using Matlab software to run a program compiled based on Hilbert Huang transform. The results show that AE signal curve is completely corresponding to tensile load-displacement curve in fabric tensile process, and characterizations of three failure modes about structure change, yarn deformation, and yarn fracture can be clearly distinguished. The characteristic frequency of four kinds of fabrics in structure change stage is the same as 100 Hz, which can be derived from the same source (orthogonal friction of yarns, and has nothing to do with the fabric organizational structure or density. The structure change stage has something to do with yarn strength utilization in such aspects as the AE signals characteristics of duration, amplitude, energy, and so on.

  11. High Electron Mobility Ge n-Channel Metal-Insulator-Semiconductor Field-Effect Transistors Fabricated by the Gate-Last Process with the Solid Source Diffusion Technique

    Science.gov (United States)

    Maeda, Tatsuro; Morita, Yukinori; Takagi, Shinichi

    2010-06-01

    We fabricate high-k/Ge n-channel metal-insulator-semiconductor field-effect transistors (MISFETs) by the gate-last process with the thermal solid source diffusion to achieve both of high quality source/drain (S/D) and gate stack. The n+/p junction formed by solid source diffusion technique of Sb dopant shows the excellent diode characteristics of ˜1.5×105 on/off ratio between +1 and -1 V and the quite low reverse current density of ˜4.1×10-4 A/cm2 at +1 V after the fabrication of high-k/Ge n-channel MISFETs that enable us to observe well-behaved transistor performances. The extracted electron mobility with the peak of 891 cm2/(V.s) is high enough to be superior to the Si universal electron mobility especially in low Eeff.

  12. IMPROVING KNITTED FABRICS BY A STATISTICAL CONTROL OF DIMENSIONAL CHANGES AFTER THE DYEING PROCESS

    Directory of Open Access Journals (Sweden)

    LLINARES-BERENGUER Jorge

    2017-05-01

    Full Text Available One of the most important problems that cotton knitted fabrics present during the manufacturing process is their dimensional instability, which needs to be minimised. Some of the variables that intervene in fabric shrinkage are related with its structural characteristics, use of fiber when producing yarn, the yarn count used or the dyeing process employed. Conducted under real factory conditions, the present study attempted to model the behaviour of a fabric structure after a dyeing process by contributing several algorithms that calculate dyed fabric stability after the first wash cycle. Small-diameter circular machines are used to produce garments with no side seams. This is the reason why a list of machines that produce the same fabrics for different widths needs to be made available to produce all the sizes of a given garment. Two relaxation states were distingued for interlock fabric: dyed and dry relaxation, and dyed and wash relaxation. The linear density of the yarn employed to produce sample fabric was combed cotton Ne 30. The machines used for optic bleaching were Overflow. To obtain knitting structures with optimum dimensional stability, different statistical tools were used to help us to evaluate all the production process variables (raw material, machines and process responsible for this variation. This allowed to guarantee product quality without creating costs and losses.

  13. Closed-Loop Process Control for Electron Beam Freeform Fabrication and Deposition Processes

    Science.gov (United States)

    Taminger, Karen M. (Inventor); Hafley, Robert A. (Inventor); Martin, Richard E. (Inventor); Hofmeister, William H. (Inventor)

    2013-01-01

    A closed-loop control method for an electron beam freeform fabrication (EBF(sup 3)) process includes detecting a feature of interest during the process using a sensor(s), continuously evaluating the feature of interest to determine, in real time, a change occurring therein, and automatically modifying control parameters to control the EBF(sup 3) process. An apparatus provides closed-loop control method of the process, and includes an electron gun for generating an electron beam, a wire feeder for feeding a wire toward a substrate, wherein the wire is melted and progressively deposited in layers onto the substrate, a sensor(s), and a host machine. The sensor(s) measure the feature of interest during the process, and the host machine continuously evaluates the feature of interest to determine, in real time, a change occurring therein. The host machine automatically modifies control parameters to the EBF(sup 3) apparatus to control the EBF(sup 3) process in a closed-loop manner.

  14. Low-Cost, Manufacturable, 6-Inch Wafer Bonding Process for Next-Generation 5-Junction IMM+Ge Photovoltaic Devices Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose the development of a 6-inch wafer bonding process to allow bonding of a multi-junction inverted metamorphic (IMM) tandem solar cell structure to an...

  15. Dayem bridge Josephson junctions. [for millimeter wave mixer

    Science.gov (United States)

    Barr, D. W.; Mattauch, R. J.

    1977-01-01

    The Josephson junction shows great promise as a millimeter wave mixer element. This paper discusses the physical mixing process from a first-order mathematical approach. Design and fabrication of such structures tailored for use in a 80-120 GHz mixer application is presented. Testing of the structures and a discussion of their interpretation is presented.

  16. Optimization of a plasma immersion ion implantation process for shallow junctions in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Ray, Ashok; Nori, Rajashree; Bhatt, Piyush; Lodha, Saurabh; Pinto, Richard, E-mail: rpinto@ee.iitb.ac.in; Rao, Valipe Ramgopal [Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai 400076 (India); Jomard, François; Neumann-Spallart, Michael [Groupe d' Étude de la Matière Condensée, C.N.R.S./Université de Versailles-St.Quentin, 45, Avenue des États-Unis, 78035 Versailles Cedex (France)

    2014-11-01

    A plasma immersion ion implantation (PIII) process has been developed for realizing shallow doping profiles of phosphorus and boron in silicon using an in-house built dual chamber cluster tool. High Si etch rates observed in a 5% PH{sub 3} in H{sub 2} plasma have been ascribed to high concentration of H(α) radicals. Therefore, subsequent work was carried out with 5% PH{sub 3} in He, leading to much smaller etch rates. By optical emission spectroscopy, the radical species H(α), PH*{sub 2}, and PH* have been identified. The concentration of all three species increased with pressure. Also, ion concentrations increased with pressure as evidenced by Langmuir data, with a maximum occurring at 0.12 mbar. The duty cycle of pulsed DC bias has a significant bearing on both the implantation and the etching process as it controls the leakage of positive charge collected at the surface of the silicon wafer during pulse on-time generated primarily due to secondary electron emission. The P implant process was optimized for a duty cycle of 10% or less at a pressure of 0.12 mbar with implant times as low as 30 s. Secondary ion mass spectroscopy showed a P dopant depth of 145 nm after rapid thermal annealing (RTA) at 950 °C for 5 s, resulting in a sheet resistance of 77 Ω/◻. Si n{sup +}/p diodes fabricated with phosphorus implantation using optimized PIII and RTA conditions exhibit J{sub on}/J{sub off} > 10{sup 6} with an ideality factor of nearly 1.2. Using similar conditions, shallow doping profiles of B in silicon have also been realized.

  17. Defect reduction for fabric cutting process to produce polo shirts : a case study of garment factory

    Directory of Open Access Journals (Sweden)

    Panicha Suttanako

    2014-09-01

    Full Text Available This research aims to study the factors affecting the crooked fabric cutting and to present the new cutting procedure that complies with the factors affecting the crooked fabric cutting of a case study. The defect in fabric cutting process was crooked fabric making nonconforming product. The cause and effect diagram was utilized to analyze and suggest related factors leading to the problem. It was showed that the number of times of knife sharpening and the number of layers in fabric paving would affect the crooked fabric cutting the design of experiment was applied to determine appropriate the level of these factors. The main factor significantly affected the crooked fabric cutting (p < 0.05 was the number of times of knife sharpening, but the number of layers in fabric paving and interaction between both factors would not significantly affect the crooked fabric cutting. The number of times of knife sharpening in the level 4 had been sharpened twenty times in each cutting round. The least average defective proportion was 0.0173. Then the new cutting procedure would significantly reduce average defective proportion. It could reduce the average number of defective items as 5.74 pieces in each cutting round or 70.52 percents.

  18. Four-Junction Solar Cell with 40% Target Efficiency Fabricated by Wafer Bonding and Layer Transfer: Final Technical Report, 1 January 2005 - 31 December 2007

    Energy Technology Data Exchange (ETDEWEB)

    Atwater, H. A.

    2008-11-01

    We realized high-quality InGaP/GaAs 2-junction top cells on Ge/Si, InGaAs/InP bottom cells, direct-bond series interconnection of tandem cells, and modeling of bonded 3- and 4-junction device performance.

  19. The multiphysics analysis of the metallic bipolar plate by the electrochemical micro-machining fabrication process

    Science.gov (United States)

    Lee, Yu-Ming; Lee, Shuo-Jen; Lee, Chi-Yuan; Chang, Dar-Yuan

    In this study, the flow channels of a PEM fuel cell are fabricated by the EMM process. The parametric effects of the process are studied by both numerical simulation and experimental tests. For the numerical simulation, the multiphysics model, consisting of electrical field, convection, and diffusion phenomena is applied using COMSOL software. COMSOL software is used to predict the parametric effects of the channel fabrication accuracy such as pulse rate, pulse duty cycle, inter-electrode gap and electrolytic inflow velocity. The proper experimental parameters and the relationship between the parameters and the distribution of metal removal are established from the simulated results. The experimental fabrication tests showed that a shorter pulse rate and a higher pulse current improved the fabrication accuracy, and is consistent with the numerical simulation results. The proposed simulation model could be employed as a predictive tool to provide optimal parameters for better machining accuracy and process stability of the EMM process.

  20. High-Rate Fabrication of a-Si-Based Thin-Film Solar Cells Using Large-Area VHF PECVD Processes

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Xunming [University of Toledo; Fan, Qi Hua

    2011-12-31

    The University of Toledo (UT), working in concert with it’s a-Si-based PV industry partner Xunlight Corporation (Xunlight), has conducted a comprehensive study to develop a large-area (3ft x 3ft) VHF PECVD system for high rate uniform fabrication of silicon absorber layers, and the large-area VHF PECVD processes to achieve high performance a-Si/a-SiGe or a-Si/nc-Si tandem junction solar cells during the period of July 1, 2008 to Dec. 31, 2011, under DOE Award No. DE-FG36-08GO18073. The project had two primary goals: (i) to develop and improve a large area (3 ft × 3 ft) VHF PECVD system for high rate fabrication of > = 8 Å/s a-Si and >= 20 Å/s nc-Si or 4 Å/s a-SiGe absorber layers with high uniformity in film thicknesses and in material structures. (ii) to develop and optimize the large-area VHF PECVD processes to achieve high-performance a-Si/nc-Si or a-Si/a-SiGe tandem-junction solar cells with >= 10% stable efficiency. Our work has met the goals and is summarized in “Accomplishments versus goals and objectives”.

  1. Development and demonstration of manufacturing processes for fabricating graphite/PMR-15 polyimide structures

    Science.gov (United States)

    Sheppard, C. H.; Hoggatt, J. T.; Hunter, A. B.

    1979-01-01

    The work included establishing controls on the polymer, the prepreg, composite fabrication, and quality assurance, as well as fabrication of structural elements to demonstrate the developed materials and processes. The fabricated structures were hat sections, I-beam sections, honeycomb sandwich structures, and molded graphite-reinforced fittings. The graphite/PMR-15 polyimide system was shown to be well suited for use in the 550-600 F temperature range; the processing techniques developed were proved and found potentially useful for other commercially available systems.

  2. Solution processed, hybrid 2D/3D MoS2/Si heterostructures with superior junction characteristics.

    Science.gov (United States)

    Mukherjee, Subhrajit; Biswas, Souvik; Das, Soumen; Ray, Samit K

    2017-02-03

    We report a theoretical and experimental investigation of the hybrid heterostructure interfaces between atomically thin MoS2 nanocrystals (NCs) on Si platform for their potential applications towards next generation electrical and optical devices. Mie theory based numerical analysis and COMSOL simulations based on finite element method (FEM) have been utilized to study the optical absorption characteristics and light matter interactions in variable sized MoS2 NCs. The size dependent absorption characteristics and the enhancement of electric field of the heterojunction in the UV-visible spectral range agree well with the experimental results. A lithography-free, wafer scale, 2D materials on a 3D substrate hybrid vertical heterostructure has been fabricated using colloidal n-MoS2 NCs on p-Si. The fabricated p-n heterojunction exhibited excellent junction characteristics with a high rectification ratio suitable for voltage clipper and rectifier applications. The current-voltage characteristics of the devices under illumination have been performed in the temperature range of 10-300 K. The device exhibits a high photo-to-dark current ratio of ~3 x 103 and a responsivity comparable to a commercial Si photodetector. The excellent heterojunction characteristics demonstrate the great potential of MoS2 NCs based hybrid electronic and optoelectronic devices in near future.

  3. Low-cost process for P-N junction-type solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Mooney, J.B.; Cubicciotti, D.D.; Bates, C.W. Jr.

    1980-03-01

    Spray pyrolysis of CuInS/sub 2/ was studied. The concentrations of copper and sulfur in the spray solutions were increased so as to increase the copper content of the films to the stoichiometric level. Although Auger analysis indicates that this was successful, x ray microanalysis has identified the growth of copper-rich crystals on the surfaces of the deposit. Heat treatment in H/sub 2/S did not improve the stoichiometry. The copper-rich crystals were also found on a sample sprayed from a solution with no excess copper. Heterojunctions of glass/SnO/sub 2/(Sb)/CdS/CdTe/carbon(Cu)/Ag-In were prepared with a number of methods used to restrict the junction. The various devices failed to exhibit a diode characteristic or a photo-response. Work on this project is being directed toward understanding the type of junction and how it is formed.

  4. Stereogeneous construction – fabric-formed concrete as material and process

    DEFF Research Database (Denmark)

    Manelius, Anne-Mette

    2012-01-01

    På engelsk: This paper contributes to studies of architectural potentials of fabric formwork for concrete by seeking to establish a theoretical concept that evaluates qualities of materials and principles of construction as well as aspects of the expression of concrete construction. Through plann...... experimental, practical and analytical investigations of fabric-formed concrete and the core formwork-tectonic elements of its making....... planning and teaching workshops with students, categorizing and interpreting experimental data, and reflecting and communicating knowledge, the concept Stereogeneity developed as a response to questions about the nature of concrete cast in fabric forms and the relation between the molded and the mold....... The word describes concrete as material and process. Fabric Formwork is the pivotal formwork-tectonic topic of investigation in the experimental and analytical parts of the thesis work on which this paper is based. The youth of the architectural application of construction methods for fabric formwork...

  5. Application of foams to the processing of fabrics. Interim report, October 1, 1977-March 31, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Duke, M.W.

    1979-04-01

    The primary objective of this project is to reduce the energy requirements for finishing fabrics by drastically reducing the water required to wet process the fabrics. Since less water is used, less energy is consumed in the evaporation of water. This is accomplished by replacing much of the water with air, making a foam and using it as the application medium. In the first six months of the project the practicality of foam fabric finishing on a commercial basis had been established. Limited yardage of fabrics equivalent in performance to conventionally wet finished fabrics were processed. In these mill trials, a range of foam fabric finishes including softeners, hand builders, durable press and shrink-resistant types were applied to cotton sheeting, corduroy and polyester/cellulosic blends, etc. In all cases, substantial energy savings were realized. Since the issuance of the first and second interim reports, commercial practice of foam fabric finishing continues to grow with cumulative total estimated as approaching 200,000,000 yards. A number of companies are currently using foam fabric finishing as a commercial production process. Additionally, the pilot range has been used to demonstrate foam fabric finishing to over twenty companies. The range has been used to demonstrate the foam acid dyeing of nylon carpets to several companies in this specialized area of textile processing. Active work still continues with these companies since the foam dyeing of carpets involves only about 1/5 the water used in the normal continuous dyeing of carpets. At the time of writing two carpet companies are actively working to evaluate foam dyeing on a mill scale. (LCL)

  6. Enhanced fabrication process of zinc oxide nanowires for optoelectronics

    Energy Technology Data Exchange (ETDEWEB)

    García Núñez, C., E-mail: carlos.garcia@uam.es [Grupo de Electrónica y Semiconductores, Departamento de Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Pau, J.L.; Ruíz, E.; García Marín, A.; García, B.J.; Piqueras, J. [Grupo de Electrónica y Semiconductores, Departamento de Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Shen, G.; Wilbert, D.S.; Kim, S.M.; Kung, P. [Department of Electrical and Computer Engineering, the University of Alabama, Tuscaloosa, AL 35487 (United States)

    2014-03-31

    Zinc oxide (ZnO) nanowires (NWs) based ultraviolet (UV) sensors have been fabricated using different assembly techniques to form functional structures, aiming at the improvement of the performance of NW-based sensors for optoelectronic applications. NWs with diameters and lengths varying between 90–870 nm and 2–20 μm, respectively, were synthesized by controlling the growth conditions in a chemical vapor transport system. Optical properties of NWs were studied by means of transmission spectroscopy. Electrical properties of single ZnO NW-based sensors were analyzed in dark and under UV illumination (at photon wavelength of λ < 370 nm) as a function of the NW diameter. Results of the study indicate that reduction of the NW diameter below 200 nm leads to an improvement of the photocurrent (at λ < 370 nm) up to 10{sup 2} μA and a decrease of the decay time around 150 s. These enhancements may help to improve the performance of ZnO-based optoelectronic devices. - Highlights: • ZnO nanowires (NWs) with diameters 90–870 nm were grown by chemical vapor transport. • ZnO NWs showed strong absorption in the UV range. • Different assembly techniques were tested for preparing ZnO NW-based UV sensors. • Sensor photoresponses were around 10{sup 3} A/W. • Reducing NW diameter below 200 nm improved sensor photosensitivity.

  7. The National Shipbuilding Research Program. Automated Process Application in Steel Fabrication and Subassembly Facilities; Phase I (Process Analysis)

    Science.gov (United States)

    1999-05-01

    6 Automated Process Application in Steel Fabrication and Subassembly Facilities; Phase I ( Process Analysis ) U.S. DEPARTMENT OF THE NAVY CARDEROCK...Subassembly Facilities; Phase I ( Process Analysis ) 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e

  8. A Course on Plasma Processing in Integrated Circuit Fabrication.

    Science.gov (United States)

    Sawin, Herbert H.; Reif, Rafael

    1983-01-01

    Describes a course, taught jointly by electrical/chemical engineering departments at the Massachusetts Institute of Technology, designed to teach the fundamental science of plasma processing as well as to give an overview of the present state of industrial processes. Provides rationale for course development, texts used, class composition, and…

  9. Preliminary Evaluation of Mechanical Properties of Co-Cr Alloys Fabricated by Three New Manufacturing Processes.

    Science.gov (United States)

    Jang, Seong-Ho; Lee, Dae-Ho; Ha, Jung-Yun; Hanawa, Takao; Kim, Kyo-Han; Kwon, Tae-Yub

    2015-01-01

    A preliminary tensile test was performed to evaluate the mechanical properties of cobalt-chromium (Co-Cr) alloys fabricated by three new manufacturing processes: metal milling, milling for soft metal, and rapid prototyping (n=6). For comparison, the three alloy materials were also used to fabricate specimens by a casting procedure. In all groups tested, the proof strength and elongation were over 500 MPa and 2%, respectively. The milled soft alloy in particular showed a substantially greater elongation, whereas the alloy fabricated by rapid prototyping exhibited a higher proof strength.

  10. An induced junction photovoltaic cell

    Science.gov (United States)

    Call, R. L.

    1974-01-01

    Silicon solar cells operating with induced junctions rather than diffused junctions have been fabricated and tested. Induced junctions were created by forming an inversion layer near the surface of the silicon by supplying a sheet of positive charge above the surface. Measurements of the response of the inversion layer cell to light of different wavelengths indicated it to be more sensitive to the shorter wavelengths of the sun's spectrum than conventional cells. The greater sensitivity occurs because of the shallow junction and the strong electric field at the surface.

  11. Fabrication of FeSe superconducting films with chemical transport deposition process

    Science.gov (United States)

    Feng, J. Q.; Zhang, S. N.; Liu, J. X.; Hao, Q. B.; Li, C. S.; Zhang, P. X.

    2017-07-01

    FeSe Superconducting films were fabricated with a chemical transport deposition process. During the fabrication process, Fe foils were adopted as substrates and Se powders were put at one end of the tube furnace. During the heating process, Se powders were vaporized, and vaporized atoms were carried by Ar flow and deposited on the Fe substrates. With a heat treatment process under proper temperature, superconducting tetragonal β-FeSe phase can be obtained. The effects of key parameters, including the sintering temperatures and the distances between Fe substrates and Se source on the phase composition and morphology of the obtained films were systematically investigated. The superconducting transition temperature of 7.8 K was obtained on the optimized film. By further optimization of the heat treatment process, it is promising to fabricate FeSe films with higher superconducting phase content and better superconducting properties.

  12. Test program on the release characteristics of Kr-85 from remote fuel fabrication process

    Energy Technology Data Exchange (ETDEWEB)

    Park, Geun Il; Lee, J. W.; Kim, S. S. [and others

    2003-01-01

    In order to investigate the release kinetics of Kr-85 fission gas during DUPIC fuel fabrication process using spent fuel materials, the test equipment and its procedure was developed. The purpose of this test involves the measurement of Kr-85 released during OREOX process in DUPIC fuel fabrication as well as the analysis of fission- gas release kinetics with the variation of fuel fabrication conditions. Gas monitoring system installed inside glove box was located at out-cell of DFDF(DUPIC Fuel Fabrication Facility) at which OREOX and tube furnaces have already installed inside hot cell. The use of glove box is aimed for preventing a gas release from sampling gas line under negative pressure. Based on the allowable discharge concentration of Kr-85 to environment and the preliminary analysis assuming total released amount a year, environmental impact according to Kr-85 measuring test would be minimal.

  13. A Fully Contained Resin Infusion Process for Fiber-Reinforced Polymer Composite Fabrication and Repair

    Science.gov (United States)

    2013-01-01

    Assisted Resin Transfer Molding ( VARTM ) process is applicable for fiber-reinforced polymer (FRP) composite fabrication and repair. However, VARTM in...scenario is a fully enclosed VARTM system that limits the need for laboratory or manufacturing equipment. The Bladder-Bag VARTM (BBVARTM) technique...composite fabrication, VARTM , composite repair, in-field repair 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18. NUMBER

  14. More steps towards process automation for optical fabrication

    Science.gov (United States)

    Walker, David; Yu, Guoyu; Beaucamp, Anthony; Bibby, Matt; Li, Hongyu; McCluskey, Lee; Petrovic, Sanja; Reynolds, Christina

    2017-06-01

    In the context of Industrie 4.0, we have previously described the roles of robots in optical processing, and their complementarity with classical CNC machines, providing both processing and automation functions. After having demonstrated robotic moving of parts between a CNC polisher and metrology station, and auto-fringe-acquisition, we have moved on to automate the wash-down operation. This is part of a wider strategy we describe in this paper, leading towards automating the decision-making operations required before and throughout an optical manufacturing cycle.

  15. Scalable shape-controlled fabrication of curved microstructures using a femtosecond laser wet-etching process

    Energy Technology Data Exchange (ETDEWEB)

    Bian, Hao; Yang, Qing; Chen, Feng, E-mail: chenfeng@mail.xjtu.edu.cn; Liu, Hewei; Du, Guangqing; Deng, Zefang; Si, Jinhai; Yun, Feng; Hou, Xun

    2013-07-01

    Materials with curvilinear surface microstructures are highly desirable for micro-optical and biomedical devices. However, realization of such devices efficiently remains technically challenging. This paper demonstrates a facile and flexible method to fabricate curvilinear microstructures with controllable shapes and dimensions. The method composes of femtosecond laser exposures and chemical etching process with the hydrofluoric acid solutions. By fixed-point and step-in laser irradiations followed by the chemical treatments, concave microstructures with different profiles such as spherical, conical, bell-like and parabola were fabricated on silica glasses. The convex structures were replicated on polymers by the casting replication process. In this work, we used this technique to fabricate high-quality microlens arrays and high-aspect-ratio microwells which can be used in 3D cell culture. This approach offers several advantages such as high-efficient, scalable shape-controllable and easy manipulations. - Highlights: • We demonstrate a flexible method to fabricate curvilinear microstructures. • This method composes of femtosecond laser exposures and chemical etching process. • Concave microstructures with different profiles were fabricated on silica glasses. • High-quality microlens arrays and high-aspect-ratio microwells were fabricated.

  16. The Effects of Dyeing and Finishing Pretreatment Process to the Sliver Fiber Shielding Fabric and the Reasons

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tan; MA Jian-wei; GUO Kun; XU Hong-xing

    2014-01-01

    Through the silver fiber and cotton mixed silver fiber shielding fabric, not only soft and comfortable, it can wear personal, but also has excellent anti electromagnetic shielding effect. Fabric in dyeing and finishing process, may cause some damage on the silver fiber, influence the shielding performance of shielding fabric. Therefore, in this paper, through the experimental and analysis, find dyeing and finishing process may affect silver fiber shielding fabric and the reasons.

  17. Enhanced Efficiency of GaAs Single-Junction Solar Cells with Inverted-Cone-Shaped Nanoholes Fabricated Using Anodic Aluminum Oxide Masks

    Directory of Open Access Journals (Sweden)

    Kangho Kim

    2013-01-01

    Full Text Available The GaAs solar cells are grown by low-pressure metalorganic chemical vapor deposition (LP-MOCVD and fabricated by photolithography, metal evaporation, annealing, and wet chemical etch processes. Anodized aluminum oxide (AAO masks are prepared from an aluminum foil by a two-step anodization method. Inductively coupled plasma dry etching is used to etch and define the nanoarray structures on top of an InGaP window layer of the GaAs solar cells. The inverted-cone-shaped nanoholes with a surface diameter of about 50 nm are formed on the top surface of the solar cells after the AAO mask removal. Photovoltaic and optical characteristics of the GaAs solar cells with and without the nanohole arrays are investigated. The reflectance of the AAO nanopatterned samples is lower than that of the planar GaAs solar cell in the measured range. The short-circuit current density increased up to 11.63% and the conversion efficiency improved from 10.53 to 11.57% under 1-sun AM 1.5 G conditions by using the nanohole arrays. Dependence of the efficiency enhancement on the etching depth of the nanohole arrays is also investigated. These results show that the nanohole arrays fabricated with an AAO technique may be employed to improve the light absorption and, in turn, the conversion efficiency of the GaAs solar cell.

  18. Generic nano-imprint process for fabrication of nanowire arrays

    Energy Technology Data Exchange (ETDEWEB)

    Pierret, Aurelie; Hocevar, Moira; Algra, Rienk E; Timmering, Eugene C; Verschuuren, Marc A; Immink, George W G; Verheijen, Marcel A; Bakkers, Erik P A M [Philips Research Laboratories Eindhoven, High Tech Campus 11, 5656 AE Eindhoven (Netherlands); Diedenhofen, Silke L [FOM Institute for Atomic and Molecular Physics c/o Philips Research Laboratories, High Tech Campus 4, 5656 AE Eindhoven (Netherlands); Vlieg, E, E-mail: e.p.a.m.bakkers@tue.nl [IMM, Solid State Chemistry, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands)

    2010-02-10

    A generic process has been developed to grow nearly defect-free arrays of (heterostructured) InP and GaP nanowires. Soft nano-imprint lithography has been used to pattern gold particle arrays on full 2 inch substrates. After lift-off organic residues remain on the surface, which induce the growth of additional undesired nanowires. We show that cleaning of the samples before growth with piranha solution in combination with a thermal anneal at 550 deg. C for InP and 700 deg. C for GaP results in uniform nanowire arrays with 1% variation in nanowire length, and without undesired extra nanowires. Our chemical cleaning procedure is applicable to other lithographic techniques such as e-beam lithography, and therefore represents a generic process.

  19. A New Fabrication Process for Thin-Film Multijunction Thermal Converters

    Energy Technology Data Exchange (ETDEWEB)

    WUNSCH,THOMAS F.; KINARD,J.R.; MANGINELL,RONALD P.; SOLOMON JR.,OTIS M.; LIPE,T.E.; JUNGLING,KENNETH CORNEAL

    2000-12-08

    Advanced thin film processing and packaging technologies are employed in the fabrication of new planar thin-film multifunction thermal converters. The processing, packaging, and design features build on experience gained from prior NIST demonstrations of thin-film converters and are optimized for improved sensitivity, bandwidth, manufacturability, and reliability.

  20. Stereogeneous construction – fabric-formed concrete as material and process

    DEFF Research Database (Denmark)

    Manelius, Anne-Mette

    2012-01-01

    På engelsk: This paper contributes to studies of architectural potentials of fabric formwork for concrete by seeking to establish a theoretical concept that evaluates qualities of materials and principles of construction as well as aspects of the expression of concrete construction. Through...... planning and teaching workshops with students, categorizing and interpreting experimental data, and reflecting and communicating knowledge, the concept Stereogeneity developed as a response to questions about the nature of concrete cast in fabric forms and the relation between the molded and the mold....... The word describes concrete as material and process. Fabric Formwork is the pivotal formwork-tectonic topic of investigation in the experimental and analytical parts of the thesis work on which this paper is based. The youth of the architectural application of construction methods for fabric formwork...

  1. Copper/bamboo fabric composite prepared via a silver catalytic electroless deposition process for electromagnetic shielding

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Qian; Lu, Yinxiang [Fudan Univ., Shanghai (China). Dept. of Materials Science

    2013-09-15

    Copper/bamboo fabric composite prepared via a silver catalytic electroless plating process is reported. The microstructure of the composite was analyzed by means of scanning electron microscopy, which illustrated that the copper coating was composed of spherical particles and clusters. The composition and chemical state of the metal layer were measured using X-ray diffraction and energy-dispersive X-ray analysis spectra; copper and a small amount of nickel were detected. Mechanical properties were measured based on a standard (ISO 13934-1:1999) for the fabrics with and without copper coating. The breaking force for the composite was improved by about 16.8% compared to uncoated bamboo fabric. The electromagnetic interference shielding effectiveness of the composite was more than 40 dB at frequencies ranging from 0.2 to 1000MHz. The copper coating on bamboo fabric passed the Scotch {sup registered} -tape test. (orig.)

  2. Fabrication of three-dimensional collagen scaffold using an inverse mould-leaching process.

    Science.gov (United States)

    Ahn, SeungHyun; Lee, SuYeon; Cho, Youngseok; Chun, Wook; Kim, GeunHyung

    2011-09-01

    Natural biopolymers, such as collagen or chitosan, are considered ideal for biomedical scaffolds. However, low processability of the materials has hindered the fabrication of designed pore structures controlled by various solid freeform-fabrication methods. A new technique to fabricate a biomedical three-dimensional collagen scaffold, supplemented with a sacrificial poly(ethylene oxide) mould is proposed. The fabricated collagen scaffold shows a highly porous surface and a three-dimensional structure with high porosity as well as mechanically stable structure. To show its feasibility for biomedical applications, fibroblasts/keratinocytes were co-cultured on the scaffold, and the cell proliferation and cell migration of the scaffold was more favorable than that obtained with a spongy-type collagen scaffold.

  3. Advanced fabrication process for combined atomic force-scanning electrochemical microscopy (AFM-SECM) probes.

    Science.gov (United States)

    Eifert, Alexander; Mizaikoff, Boris; Kranz, Christine

    2015-01-01

    An advanced software-controlled focused ion beam (FIB) patterning process for the fabrication of combined atomic force-scanning electrochemical microscopy (AFM-SECM) probes is reported. FIB milling is a standard process in scanning probe microscopy (SPM) for specialized SPM probe fabrication. For AFM-SECM, milling of bifunctional probes usually requires several milling steps. Milling such complex multi-layer/multi-material structures using a single milling routine leads to significantly reduced fabrication times and costs. Based on an advanced patterning routine, a semi-automated FIB milling routine for fabricating combined AFM-SECM probes with high reproducibility is presented with future potential for processing at a wafer level. The fabricated bifunctional probes were electrochemically characterized using cyclic voltammetry, and their performance for AFM-SECM imaging experiments was tested. Different insulation materials (Parylene-C and SixNy) have been evaluated with respect to facilitating the overall milling process, the influence on the electrochemical behavior and the long-term stability of the obtained probes. Furthermore, the influence of material composition and layer sequence to the overall shape and properties of the combined probes were evaluated.

  4. Equalizing Si photodetectors fabricated in standard CMOS processes

    Science.gov (United States)

    Guerrero, E.; Aguirre, J.; Sánchez-Azqueta, C.; Royo, G.; Gimeno, C.; Celma, S.

    2017-05-01

    This work presents a new continuous-time equalization approach to overcome the limited bandwidth of integrated CMOS photodetectors. It is based on a split-path topology that features completely decoupled controls for boosting and gain; this capability allows a better tuning of the equalizer in comparison with other architectures based on the degenerated differential pair, which is particularly helpful to achieve a proper calibration of the system. The equalizer is intended to enhance the bandwidth of CMOS standard n-well/p-bulk differential photodiodes (DPDs), which falls below 10MHz representing a bottleneck in fully integrated optoelectronic interfaces to fulfill the low-cost requirements of modern smart sensors. The proposed equalizer has been simulated in a 65nm CMOS process and biased with a single supply voltage of 1V, where the bandwidth of the DPD has been increased up to 3 GHz.

  5. Laser Control of Self-Organization Process in Microscopic Region and Fabrication of Fine Microporous Structure

    Directory of Open Access Journals (Sweden)

    Yukimasa Matsumura

    2012-01-01

    Full Text Available We present a controlling technique of microporous structure by laser irradiation during self-organization process. Self-organization process is fabrication method of microstructure. Polymer solution was dropped on the substrate at high humid condition. Water in air appears dropping air temperature below the dew point. The honeycomb structure with regularly aligned pores on the film was fabricated by attaching water droplets onto the solution surface. We demonstrate that it was possible to prevent forming pores at the region of laser irradiation and flat surface was fabricated. We also demonstrated that a combination structure with two pore sizes and flat surface was produced by a single laser-pulse irradiation. Our method is a unique microfabrication processing technique that combines the advantages of bottom-up and top-down techniques. This method is a promising technique that can be applied to produce for photonic crystals, biological cell culturing, surface science and electronics fields, and so forth.

  6. The design, fabrication, and test of a new VLSI hybrid analog-digital neural processing element

    Science.gov (United States)

    Deyong, Mark R.; Findley, Randall L.; Fields, Chris

    1992-01-01

    A hybrid analog-digital neural processing element with the time-dependent behavior of biological neurons has been developed. The hybrid processing element is designed for VLSI implementation and offers the best attributes of both analog and digital computation. Custom VLSI layout reduces the layout area of the processing element, which in turn increases the expected network density. The hybrid processing element operates at the nanosecond time scale, which enables it to produce real-time solutions to complex spatiotemporal problems found in high-speed signal processing applications. VLSI prototype chips have been designed, fabricated, and tested with encouraging results. Systems utilizing the time-dependent behavior of the hybrid processing element have been simulated and are currently in the fabrication process. Future applications are also discussed.

  7. The design, fabrication, and test of a new VLSI hybrid analog-digital neural processing element

    Science.gov (United States)

    Deyong, Mark R.; Findley, Randall L.; Fields, Chris

    1992-01-01

    A hybrid analog-digital neural processing element with the time-dependent behavior of biological neurons has been developed. The hybrid processing element is designed for VLSI implementation and offers the best attributes of both analog and digital computation. Custom VLSI layout reduces the layout area of the processing element, which in turn increases the expected network density. The hybrid processing element operates at the nanosecond time scale, which enables it to produce real-time solutions to complex spatiotemporal problems found in high-speed signal processing applications. VLSI prototype chips have been designed, fabricated, and tested with encouraging results. Systems utilizing the time-dependent behavior of the hybrid processing element have been simulated and are currently in the fabrication process. Future applications are also discussed.

  8. Porous Gold Films Fabricated by Wet-Chemistry Processes

    Directory of Open Access Journals (Sweden)

    Aymeric Pastre

    2016-01-01

    Full Text Available Porous gold films presented in this paper are formed by combining gold electroless deposition and polystyrene beads templating methods. This original approach allows the formation of conductive films (2 × 106 (Ω·cm−1 with tailored and interconnected porosity. The porous gold film was deposited up to 1.2 μm on the silicon substrate without delamination. An original zirconia gel matrix containing gold nanoparticles deposited on the substrate acts both as an adhesion layer through the creation of covalent bonds and as a seed layer for the metallic gold film growth. Dip-coating parameters and gold electroless deposition kinetics have been optimized in order to create a three-dimensional network of 20 nm wide pores separated by 20 nm thick continuous gold layers. The resulting porous gold films were characterized by GIXRD, SEM, krypton adsorption-desorption, and 4-point probes method. The process is adaptable to different pore sizes and based on wet-chemistry. Consequently, the porous gold films presented in this paper can be used in a wide range of applications such as sensing, catalysis, optics, or electronics.

  9. Fabrication of photovoltaic laser energy converterby MBE

    Science.gov (United States)

    Lu, Hamilton; Wang, Scott; Chan, W. S.

    1993-01-01

    A laser-energy converter, fabricated by molecular beam epitaxy (MBE), was developed. This converter is a stack of vertical p-n junctions connected in series by low-resistivity, lattice matched CoSi2 layers to achieve a high conversion efficiency. Special high-temperature electron-beam (e-beam) sources were developed especially for the MBE growth of the junctions and CoSi2 layers. Making use of the small (greater than 1.2 percent) lattice mismatch between CoSi2 and Si layers, high-quality and pinhole-free epilayers were achieved, providing a capability of fabricating all the junctions and connecting layers as a single growth process with one pumpdown. Well-defined multiple p-n junctions connected by CoSi2 layers were accomplished by employing a low growth temperature (greater than 700 C) and a low growth rate (less than 0.5 microns/hour). Producing negligible interdiffusion, the low growth temperature and rate also produced negligible pinholes in the CoSi2 layers. For the first time, a stack of three p-n junctions connected by two 10(exp -5) Ohm-cm CoSi2 layers was achieved, meeting the high conversion efficiency requirement. This process can now be optimized for high growth rate to form a practical converter with 10 p-n junctions in the stack.

  10. Novel printing process for the fabrication of cantilever structures by the partially controlled sintering of ink

    Science.gov (United States)

    Kanazawa, Shusuke; Kusaka, Yasuyuki; Yamamoto, Noritaka; Ushijima, Hirobumi

    2017-01-01

    We present a novel process for manufacturing cantilever structures by the additive stacking of ink layers. The three-dimensional transfer of printed mechanical parts was achieved by optimizing the ink-sintering conditions to guarantee the structural integrity of the printed parts and provide adequate differences in adhesion strengths between the receiver and donor interfaces. A metal–insulator–metal cantilever structure with a bottom electrode, air insulator, and cantilevered top electrode was fabricated on a flexible film, forming a successful capacitive bending sensor for use on human bodies. This process allows highly efficient device fabrication in the MEMS field.

  11. Influence of zone purification process on TlBr crystals for radiation detector fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Hitomi, Keitaro [Department of Electronics, Tohoku Institute of Technology, 35-1 Yagiyama Kasumi-cho, Taihaku-ku, Sendai 982-8577 (Japan)], E-mail: hitomi@tohtech.ac.jp; Onodera, Toshiyuki; Shoji, Tadayoshi [Department of Electronics, Tohoku Institute of Technology, 35-1 Yagiyama Kasumi-cho, Taihaku-ku, Sendai 982-8577 (Japan)

    2007-08-21

    Thallium bromide (TlBr) is a wide gap compound semiconductor and is a promising material for fabrication of nuclear radiation detectors. In this study, the conventional zone refining method was employed to reduce the concentration of impurities in the TlBr crystals. In order to evaluate the efficiency of the zone purification, the zone purification process was repeated up to 300 times. The resistivity, the charge transport properties, and the spectroscopic performance of TlBr detectors fabricated from the crystals zone purified 1 time, 100 times, and 300 times were compared in this study in order to clarify the effectiveness of the zone purification process.

  12. Mechanical design and fabrication processes for the ALS third-harmonic cavities

    Energy Technology Data Exchange (ETDEWEB)

    Franks, M; Henderson, T; Hernandez, K; Otting, D; Plate, D; Rimmer, R

    1999-03-25

    It is planned to install five third-harmonic (1.5 GHz) RF Cavities in May/June 1999 as an upgrade to the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory (LBNL). This paper presents mechanical design features, their experiences in using electronic design models to expedite the manufacturing process, and the fabrication processes employed to produce these cavities for the ALS. They discuss some of the lessons learned from the PEP-II RF Cavity design and fabrication, and outline the improvements incorporated in the new design. They also report observations from the current effort.

  13. Application of foams to the processing of fabrics. Final report, October 1, 1977-September 30, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Duke, M.W.

    1979-12-01

    In mill trials, a range of foam fabric finishes including softeners, hand builders, and durable-press and shrink-resistant types were applied to cotton sheeting, corduroy, and polyester/cellulosic blends, etc. In all cases, substantial energy savings were realized. A number of companies are currently using foam fabric finishing as a commercial production process. Additionally, the pilot range has been used to demonstrate foam fabric finishing to over twenty companies. The range has been used to demonstrate the foam acid dyeing of nylon carpets to several companies in this specialized area of textile processing. Active work still continues with these companies since the foam dyeing of carpets involves only about 1/5 the water used in the normal continuous dyeing of carpets. Energy conservation is realized both from reduced steam consumption in steaming colors and less heat used for drying.

  14. Fabrication of Vacuum-Sealed Capacitive Micromachined Ultrasonic Transducer Arrays Using Glass Reflow Process

    Directory of Open Access Journals (Sweden)

    Nguyen Van Toan

    2016-04-01

    Full Text Available This paper presents a process for the fabrication of vacuum-sealed capacitive micromachined ultrasonic transducer (CMUT arrays using glass reflow and anodic bonding techniques. Silicon through-wafer interconnects have been investigated by the glass reflow process. Then, the patterned silicon-glass reflow wafer is anodically bonded to an SOI (silicon-on-insulator wafer for the fabrication of CMUT devices. The CMUT 5 × 5 array has been successfully fabricated. The resonant frequency of the CMUT array with a one-cell radius of 100 µm and sensing gap of 3.2 µm (distance between top and bottom electrodes is observed at 2.84 MHz. The Q factor is approximately 1300 at pressure of 0.01 Pa.

  15. Relationships between the Processing Parameters of Melt Blown Nonwoven Fabric and Its Structure and Filtration Property

    Institute of Scientific and Technical Information of China (English)

    潘莺; 王善元

    2001-01-01

    Based on the processing experiment and sodium flame test this paper deals with the relationship between processing parameters, structure, and filtration property of melt blown fabric. Through the image analysis of Questar micro-images in combination with the SEM observation and the measurement of some macrostructure indices, the relationship between the processing parameters and the structure especially the microstructure is emphasized Finally the effect of somestructure factors on filtration properties is discussed theoretically.

  16. Literature on fabrication of tungsten for application in pyrochemical processing of spent nuclear fuels

    Energy Technology Data Exchange (ETDEWEB)

    Edstrom, C.M.; Phillips, A.G.; Johnson, L.D.; Corle, R.R.

    1980-10-11

    The pyrochemical processing of nuclear fuels requires crucibles, stirrers, and transfer tubing that will withstand the temperature and the chemical attack from molten salts and metals used in the process. This report summarizes the literature that pertains to fabrication (joining, chemical vapor deposition, plasma spraying, forming, and spinning) is the main theme. This report also summarizes a sampling of literature on molbdenum and the work previously performed at Argonne National Laboratory on other container materials used for pyrochemical processing of spent nuclear fuels.

  17. Mus81 cleavage of Holliday junctions: a failsafe for processing meiotic recombination intermediates?

    Science.gov (United States)

    Gaskell, Louise J; Osman, Fekret; Gilbert, Robert J C; Whitby, Matthew C

    2007-04-04

    The Holliday junction (HJ) is a central intermediate of homologous recombination. Its cleavage is critical for the formation of crossover recombinants during meiosis, which in turn helps to establish chiasmata and promote genetic diversity. Enzymes that cleave HJs, called HJ resolvases, have been identified in all domains of life except eukaryotic nuclei. Controversially, the Mus81-Eme1 endonuclease has been proposed to be an example of a eukaryotic nuclear resolvase. However, hitherto little or no HJ cleavage has been detected in recombinant preparations of Mus81-Eme1. Here, we report the purification of active forms of recombinant Schizosaccharomyces pombe Mus81-Eme1 and Saccharomyces cerevisiae Mus81-Mms4, which display robust HJ cleavage in vitro, which, in the case of Mus81-Eme1, is as good as the archetypal HJ resolvase RuvC in single turnover kinetic analysis. We also present genetic evidence that suggests that this activity might be utilised as a back-up to Mus81-Eme1's main activity of cleaving nicked HJs during meiosis in S. pombe.

  18. Additive advantage in characteristics of MIMCAPs on flexible silicon (100) fabric with release-first process

    KAUST Repository

    Ghoneim, Mohamed T.

    2013-11-20

    We report the inherent increase in capacitance per unit planar area of state-of-the art high-κ integrated metal/insulator/metal capacitors (MIMCAPs) fabricated on flexible silicon fabric with release-first process. We methodically study and show that our approach to transform bulk silicon (100) into a flexible fabric adds an inherent advantage of enabling higher integration density dynamic random access memory (DRAM) on the same chip area. Our approach is to release an ultra-thin silicon (100) fabric (25 μm thick) from the bulk silicon wafer, then build MIMCAPs using sputtered aluminium electrodes and successive atomic layer depositions (ALD) without break-ing the vacuum of a high-κ aluminium oxide sandwiched between two tantalum nitride layers. This result shows that we can obtain flexible electronics on silicon without sacrificing the high density integration aspects and also utilize the non-planar geometry associated with fabrication process to obtain a higher integration density compared to bulk silicon integration due to an increased normalized capacitance per unit planar area. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Processing and Characterization of Peti Composites Fabricated by High Temperature Vartm (Section)

    Science.gov (United States)

    Ghose, Sayata; Cano, Roberto J.; Watson, Kent A.; Britton, Sean M.; Jensen, Brian J.; Connell, John W.; Smith, Joseph G., Jr.; Loos, Alfred C.; Heider, Dirk

    2011-01-01

    The use of composites as primary structures on aerospace vehicles has increased dramatically over the past decade, but so have the production costs associated with their fabrication. For certain composites, high temperature vacuum assisted resin transfer molding (HT-VARTM) can offer reduced fabrication costs compared to conventional autoclave techniques. The process has been successfully used with phenylethynyl terminated imide (PETI) resins developed by NASA Langley Research Center (LaRC). In the current study, three PETI resins have been used to make test specimens using HT-VARTM. Based on previous work at NASA LaRC, larger panels with a quasi-isotropic lay-up were fabricated. The resultant composite specimens exhibited void contents of 3% by volume depending on the type of carbon fabric preform used. Mechanical properties of the panels were determined at both room and elevated temperatures. Fabric permeability characterizations and limited process modeling efforts were carried out to determine infusion times and composite panel size limitations. In addition, new PETI based resins were synthesized specifically for HT-VARTM.

  20. Shape distortions in fabric reinforced composite products due to processing induced fibre reorientation

    NARCIS (Netherlands)

    Lamers, Edwin Adriaan Derk

    2004-01-01

    Woven fabric reinforced composite materials are typically applied in plate or shell structures, such as ribs, stiffeners and skins. Products of these types can be produced with several production processes. A few examples are diaphragm forming, matched metal die forming and rubber press forming. Sha

  1. Shape distortions in fabric reinforced composite products due to processing induced fibre reorientation

    NARCIS (Netherlands)

    Lamers, E.A.D.

    2004-01-01

    Woven fabric reinforced composite materials are typically applied in plate or shell structures, such as ribs, stiffeners and skins. Products of these types can be produced with several production processes. A few examples are diaphragm forming, matched metal die forming and rubber press forming.

  2. Analysis of in situ Reaction and Pressureless Infiltration Process in Fabricating TiC/Mg Composites

    Institute of Scientific and Technical Information of China (English)

    Qun DONG; Liqing CHEN; Mingjiu ZHAO; Jing BI

    2004-01-01

    An innovative processing route, in situ reaction combined with pressureless infiltration, was adopted to fabricate magnesium matrix composites, where the reinforcement TiC formed in situ from elemental Ti and C powders and molten Mg spontaneously infiltrated the preform of Ti and C. The influences of primarily elemental particle sizes,synthesizing temperature, holding time etc on in situ reactive infiltration for Mg-Ti-C system were systematically investigated in order to explore the mechanism of this process. In fabricating TiC/Mg composites, Mg can not only spontaneously infiltrate the preform of reinforcement and thus densify the as fabricated composites as matrix metal, but also it can accelerate the in situ reaction process and lower the synthesizing temperature of Ti and C as well. In situ reaction of Ti and C and Mg infiltration processes are essentially overlapping and interacting during fabrication of TiC/Mg composites. The mechanism proposed in this paper can be used to explain the formation and morphologies of the reinforcement phase TiC.

  3. Fabrication process scale-up and optimization for a boron-aluminum composite radiator

    Science.gov (United States)

    Okelly, K. P.

    1973-01-01

    Design approaches to a practical utilization of a boron-aluminum radiator for the space shuttle orbiter are presented. The program includes studies of laboratory composite material processes to determine the feasibility of a structural and functional composite radiator panel, and to estimate the cost of its fabrication. The objective is the incorporation of boron-aluminum modulator radiator on the space shuttle.

  4. Personalized implant for high tibial opening wedge: combination of solid freeform fabrication with combustion synthesis process.

    Science.gov (United States)

    Zhim, Fouad; Ayers, Reed A; Moore, John J; Moufarrège, Richard; Yahia, L'Hocine

    2012-09-01

    In this work a new generation of bioceramic personalized implants were developed. This technique combines the processes of solid freeform fabrication (SFF) and combustion synthesis (CS) to create personalized bioceramic implants with tricalcium phosphate (TCP) and hydroxyapatite (HA). These porous bioceramics will be used to fill the tibial bone gap created by the opening wedge high tibial osteotomy (OWHTO). A freeform fabrication with three-dimensional printing (3DP) technique was used to fabricate a metallic mold with the same shape required to fill the gap in the opening wedge osteotomy. The mold was subsequently used in a CS process to fabricate the personalized ceramic implants with TCP and HA compositions. The mold geometry was designed on commercial 3D CAD software. The final personalized bioceramic implant was produced using a CS process. This technique was chosen because it exploits the exothermic reaction between P₂O₅ and CaO. Also, chemical composition and distribution of pores in the implant could be controlled. To determine the chemical composition, the microstructure, and the mechanical properties of the implant, cylindrical shapes were also fabricated using different fabrication parameters. Chemical composition was performed by X-ray diffraction. Pore size and pore interconnectivity was measured and analyzed using an electronic microscope system. Mechanical properties were determined by a mechanical testing system. The porous TCP and HA obtained have an open porous structure with an average 400 µm channel size. The mechanical behavior shows great stiffness and higher load to failure for both ceramics. Finally, this personalized ceramic implant facilitated the regeneration of new bone in the gap created by OWHTO and provides additional strength to allow accelerated rehabilitation.

  5. Flexible MgO Barrier Magnetic Tunnel Junctions.

    Science.gov (United States)

    Loong, Li Ming; Lee, Wonho; Qiu, Xuepeng; Yang, Ping; Kawai, Hiroyo; Saeys, Mark; Ahn, Jong-Hyun; Yang, Hyunsoo

    2016-07-01

    Flexible MgO barrier magnetic tunnel junction (MTJ) devices are fabricated using a transfer printing process. The flexible MTJ devices yield significantly enhanced tunneling magnetoresistance of ≈300% and improved abruptness of switching, as residual strain in the MTJ structure is released during the transfer process. This approach could be useful for flexible electronic systems that require high-performance memory components. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Comparison of Jacket Production Processes Designed by Fabric Materials and Leather

    Directory of Open Access Journals (Sweden)

    Emine Utkun

    2011-02-01

    Full Text Available Leather and leather products industry has shown a significant improvement in export area, as a result of intensive shuttle trades and demand that comes from crumbling Eastern Bloc countries in 1990's. This development has caused capacity increasing and thus makes large investments in this sector. Leather garment industry differs from woven or fabrics industry at various points. Differantation seems in raw materials features such as size, thickness, biological, chemical or physical homogenity. Due to the natural structure, leather shows different attributes in different regions. This study examines the diversity of production processes of leather and fabric designed jacket.

  7. Processing-structure-property relations in PEEK/carbon composites made from comingled fabric and prepreg

    Energy Technology Data Exchange (ETDEWEB)

    Vu-khanh, T.; Denault, J. (National Research Council of Canada, Industrial Materials Institute, Boucherville (Canada))

    1991-10-01

    The effects of the conditions of the processing of PEEK/carbon prepregs and comingled fabric on the microstructure and mechanical characteristics of the resulting composites were investigated. Results showed that, in the comingled fabric system, the fiber/matrix adhesion depends on the molding temperature, the residence time at the melt temperature, and the cooling rate. Too high molding temperature resulted in degradation of the PEEK matrix, which affected the crystallization behavior of the composites, the fiber/matrix adhesion, and the matrix properties. This effect was most important in the case of comingled systems containing sized carbon fibers. 17 refs.

  8. Material control in nuclear fuel fabrication facilities. Part I. Fuel descriptions and fabrication processes, P. O. 1236909 Final report

    Energy Technology Data Exchange (ETDEWEB)

    Borgonovi, G.M.; McCartin, T.J.; Miller, C.L.

    1978-12-01

    The report presents information on foreign nuclear fuel fabrication facilities. Fuel descriptions and fuel fabrication information for three basic reactor types are presented: The information presented for LWRs assumes that Pu--U Mixed Oxide Fuel (MOX) will be used as fuel.

  9. Bulk heterojunction organic photovoltaics from water-processable nanomaterials and their facile fabrication approaches.

    Science.gov (United States)

    Subianto, Surya; Dutta, Naba; Andersson, Mats; Choudhury, Namita Roy

    2016-09-01

    Organic thin film photovoltaics based on bulk-heterojunction donor-acceptor combinations have received significant interest due to their potential for low-cost, large-scale solution processing. However, current state-of-the-art cells utilise materials soluble mainly in halogenated solvents which pose processing challenges due to their toxicity and thus environmental hazards. In this contribution, we look at various nanomaterials, and alternative processing of these solar cells using environmentally friendly solvents, and review recently reported different strategies and approaches that are making inroads in this field. Specifically, we focus on the use of water-dispersible donors and acceptors, use of aqueous solvents for fabrication and discuss the merits of the two main approaches of water-processable solar cells; namely, through the use of water-soluble materials and the use of aqueous dispersion rather than a solution, as well as review some of the recent advances in alternative fabrication techniques.

  10. A miniature rigid/flex salinity measurement device fabricated using printed circuit processing techniques

    Science.gov (United States)

    Broadbent, H. A.; Ketterl, T. P.; Reid, C. S.

    2010-08-01

    The design, fabrication and initial performance of a single substrate, miniature, low-cost conductivity, temperature, depth (CTD) sensor board with interconnects are presented. In combination these sensors measure ocean salinity. The miniature CTD device board was designed and fabricated as the main component of a 50 mm × 25 mm × 25 mm animal-attached biologger. The board was fabricated using printed circuit processes and consists of two distinct regions on a continuous single liquid crystal polymer substrate: an 18 mm × 28 mm rigid multi-metal sensor section and a 72 mm long flexible interconnect section. The 95% confidence intervals for the conductivity, temperature and pressure sensors were demonstrated to be ±0.083 mS cm-1, 0.01 °C, and ±0.135 dbar, respectively.

  11. Novel CdTe Cell Fabrication Process with Potential for Low Cost and High Throughput

    Energy Technology Data Exchange (ETDEWEB)

    Wu, X.; Sheldon, P.

    2000-01-01

    There are several production disadvantages inherent in the conventional SnO(2)/CdS/CdTe manufacturing processes. In this paper, we report a novel manufacturing process for fabrication of polycrystalline Cd(2)SnO(4)/Zn(2)/SnO(4)/CdS/CdTe thin-film solar cells that yielded a CdS/CdTe device with an NREL-confirmed efficiency of 14.0%.

  12. Investigation of Proposed Process Sequence for the Array Automated Assembly Task, Phase 2. [low cost silicon solar array fabrication

    Science.gov (United States)

    Mardesich, N.; Garcia, A.; Bunyan, S.; Pepe, A.

    1979-01-01

    The technological readiness of the proposed process sequence was reviewed. Process steps evaluated include: (1) plasma etching to establish a standard surface; (2) forming junctions by diffusion from an N-type polymeric spray-on source; (3) forming a p+ back contact by firing a screen printed aluminum paste; (4) forming screen printed front contacts after cleaning the back aluminum and removing the diffusion oxide; (5) cleaning the junction by a laser scribe operation; (6) forming an antireflection coating by baking a polymeric spray-on film; (7) ultrasonically tin padding the cells; and (8) assembling cell strings into solar circuits using ethylene vinyl acetate as an encapsulant and laminating medium.

  13. Ecosystem protection by effluent bioremediation: silver nanoparticles impregnation in a textile fabrics process

    Energy Technology Data Exchange (ETDEWEB)

    Duran, Nelson, E-mail: duran@iqm.unicamp.br; Marcato, Priscyla D. [Universidade Estadual de Campinas, Biological Chemistry Laboratory, Instituto de Quimica (Brazil); Alves, Oswaldo L. [Universidade Estadual de Campinas, Solid State Chemistry Laboratory, Instituto de Quimica (Brazil); Silva, Joao P. S. Da; Souza, Gabriel I. H. De [Universidade de Mogi das Cruzes, Biological Chemistry and Biotechnology Laboratory, Environmental Sciences Center (Brazil); Rodrigues, Flavio A. [Universidade de Mogi das Cruzes, Material Chemistry Laboratory, Biochemical Research Center (Brazil); Esposito, Elisa [Universidade de Mogi das Cruzes, Biological Chemistry and Biotechnology Laboratory, Environmental Sciences Center (Brazil)

    2010-01-15

    This work studied a bioremediation process of silver nanoparticles with the bacterium Chromobacterium violaceum. These nanoparticles were obtained from several washes of cotton fabrics impregnated with silver nanoparticles produced by the fungus Fusarium oxysporum. The optimized growth of C. violaceum for silver nanoparticles bioremediation was obtained. The effluents of wash process of the cotton fabric were efficiently treated with C. violaceum. This treatment was based on biosorption which was very efficient for the elimination of silver nanoparticles remaining in the wash water. The bacteria after biosorption were morphologically transformed, but the normal morphology after a new culture was completely restored. The process also allowed the recovery of silver material that was leached into the effluent for a reutilization avoiding any effect to the eco-environment.

  14. A Novel RF Inductor Fabricated Through MEMS Processing and Electroless Copper Plating

    Institute of Scientific and Technical Information of China (English)

    LIYi; WUWengang; HAOYilong

    2005-01-01

    A novel radio-frequency inductor with single-crystal-silicon spiral structure suspended on glass substrate is reported. The inductor is fabricated by using an improved silicon-glass anodic bonding and deep etching releasing process combined with electroless copper plating technology. The newly developed process is proved simple, stable and easily controlled. Based on the process, the performances of the inductor, such as quality factor, inductance and operating frequency, can be adjusted by changing the structure parameters. Through the electroless copper plating, the silicon spiral structure of the inductor is encapsulated completely by highly conformal copper film. Furthermore, a thin nickel film is plated on the top of the copper layer for passivation and measurement convenience. The thickness of copper and nickel layers influences the characteristics of the inductors largely. The fabricated inductor exhibits high performances. Its quality factor has reached 27 at the frequency arrange from 9 to 11GHz.

  15. Ecosystem protection by effluent bioremediation: silver nanoparticles impregnation in a textile fabrics process

    Science.gov (United States)

    Durán, Nelson; Marcato, Priscyla D.; Alves, Oswaldo L.; Da Silva, João P. S.; De Souza, Gabriel I. H.; Rodrigues, Flávio A.; Esposito, Elisa

    2010-01-01

    This work studied a bioremediation process of silver nanoparticles with the bacterium Chromobacterium violaceum. These nanoparticles were obtained from several washes of cotton fabrics impregnated with silver nanoparticles produced by the fungus Fusarium oxysporum. The optimized growth of C. violaceum for silver nanoparticles bioremediation was obtained. The effluents of wash process of the cotton fabric were efficiently treated with C. violaceum. This treatment was based on biosorption which was very efficient for the elimination of silver nanoparticles remaining in the wash water. The bacteria after biosorption were morphologically transformed, but the normal morphology after a new culture was completely restored. The process also allowed the recovery of silver material that was leached into the effluent for a reutilization avoiding any effect to the eco-environment.

  16. Integratible Process for Fabrication of Fluidic Microduct Networks on a Single Wafer

    Energy Technology Data Exchange (ETDEWEB)

    Matzke, C.M.; Ashby, C.I.; Bridges, M.M.; Griego, L.; Wong, C.C.

    1999-09-07

    We present a microelectronics fabrication compatible process that comprises photolithography and a key room temperature SiON thin film plasma deposition to define and seal a fluidic microduct network. Our single wafer process is independent of thermo-mechanical material properties, particulate cleaning, global flatness, assembly alignment, and glue medium application, which are crucial for wafer fusion bonding or sealing techniques using a glue medium. From our preliminary experiments, we have identified a processing window to fabricate channels on silicon, glass and quartz substrates. Channels with a radius of curvature between 8 and 50 {micro}m, are uniform along channel lengths of several inches and repeatable across the wafer surfaces. To further develop this technology, we have begun characterizing the SiON film properties such as elastic modulus using nanoindentation, and chemical bonding compatibility with other microelectronic materials.

  17. Modeling of CVI process in fabrication of carbon/carbon composites by an artificial neural network

    Institute of Scientific and Technical Information of China (English)

    李爱军; 李贺军; 李克智; 顾正彬

    2003-01-01

    The chemical vapor infiltration(CVI) process in fabrication of carbon-carbon composites is very complex and highly inefficient, which adds considerably to the cost of fabrication and limits the application of the material. This paper tries to use a supervised artificial neural network(ANN) to model the nonlinear relationship between parameters of isothermal CVI(ICVI) processes and physical properties of C/C composites. A model for preprocessing dataset and selecting its topology is developed using the Levenberg-Marquardt training algorithm and trained with comprehensive dataset of tubal C/C components collected from experimental data and abundant simulated data obtained by the finite element method. A basic repository on the domain knowledge of CVI processes is established via sufficient data mining by the network. With the help of the repository stored in the trained network, not only the time-dependent effects of parameters in CVI processes but also their coupling effects can be analyzed and predicted. The results show that the ANN system is effective and successful for optimizing CVI processes in fabrication of C/C composites.

  18. THE DYEING PROCESS OF KNITTED FABRICS AT DIFFERENT TEMPERATURES USING ULTRASOUND

    Directory of Open Access Journals (Sweden)

    MITIC Jelena

    2014-05-01

    Full Text Available The dyeing of knitted fabrics made from 100 % cellulose using on-line procedure vinyl sulfonic reactive dye, with or without ultrasound energy, is carried out in this paper. The impact of temperature has been observed. The dye exhaustion is monitored using the method of absorption spectrophotometry, and the quality control of the coloration is monitored using color measurements. The acting of ultrasound on coloration consistency, as well as on some mechanical characteristics has also been examined. All examples of the ultrasound dyeing process show greater dye exhaustion in comparison to the conventional procedure. In addition, all the samples, which have been dyed with the ultrasound energy at 40°C, are significantly darker and have deeper color in comparison with the referent sample. The temperature has a great influence on kinetic energy of the dye molecules, and therefore on the diffusion processes in the dyeing system. The exhaustion chart indicates that when the temperature is lower the exhaustion degree drops. However, all the samples dyed with the ultrasound energy have bigger exhaustion. Besides that, ultrasound energy contributes to warming up the processing environment, so the additional warm up with the electricity is unnecessary, unlike the conventional way of dyeing. Since the reactive dyes chemically connect themselves with the cellulose substrate and in that way form covalent connection, the dyed fabrics have good washing consistency. Analysis results indicate that the consistencies are identical regardless the applied dyeing procedure. In other words, the dyeing method using the ultrasound energy produces the dyed fabric of the same quality. After analyzing the results of breaking force and elongation at break of knitted fabrics, it is noticeable that there is no degradation of previously mentioned knitted fabrics features (horizontally and vertically during the ultrasound wave’s activity.

  19. Homo-junction ferroelectric field-effect-transistor memory device using solution-processed lithium-doped zinc oxide thin films

    KAUST Repository

    Nayak, Pradipta K.

    2012-06-22

    High performance homo-junction field-effect transistor memory devices were prepared using solution processed transparent lithium-doped zinc oxide thin films for both the ferroelectric and semiconducting active layers. A highest field-effect mobility of 8.7 cm2/Vs was obtained along with an Ion/Ioff ratio of 106. The ferroelectric thin filmtransistors showed a low sub-threshold swing value of 0.19 V/dec and a significantly reduced device operating voltage (±4 V) compared to the reported hetero-junction ferroelectrictransistors, which is very promising for low-power non-volatile memory applications.

  20. Fabrication and characterization of semiconductor ion traps for quantum information processing

    Science.gov (United States)

    Stick, Daniel Lynn

    The electromagnetic manipulation of isolated ions has led to many advances in atomic physics, from laser cooling to precision metrology and quantum control. As technical capability in this area has grown, so has interest in building miniature electromagnetic traps for the development of large-scale quantum information processors. This thesis will primarily focus on using microfabrication techniques to build arrays of miniature ion traps, similar to techniques used in fabricating high component density microprocessors. A specific focus will be on research using a gallium arsenide/aluminum gallium arsenide heterostructure as a trap architecture, as well as the recent testing of different ion traps fabricated at outside foundries. The construction and characterization of a conventional ceramic trap capable of shuttling an ion through a junction will also be detailed, and reveal the need for moving towards lithographically fabricated traps. Combined, these serve as a set of proof-of-principle experiments pointing to methods for designing and building large scale arrays of ion traps capable of constituting a quantum information processor. As traps become smaller, electrical potentials on the electrodes have greater influence on the ion. This not only pertains to intentionally applied voltages, but also to deleterious noise sources, such as thermal Johnson noise and the more significant "patch potential" noise, which both cause motional heating of the ion. These problematic noise sources dovetail with my thesis research into trap miniaturization since their effects become more pronounced and impossible to ignore for small trap sizes. Therefore characterizing them and investigating ways to suppress them have become an important component of my research. I will describe an experiment using a pair of movable needle electrodes to measure the ion heating rate corresponding to the harmonic frequency of the trap, the ion-electrode distance, and the electrode temperature. This

  1. Step-Tapered Active-Region Mid-Infrared Quantum Cascade Lasers and Novel Fabrication Processes for Buried Heterostructures

    Science.gov (United States)

    2015-07-28

    83 shorter cavity length (~ 1.5 mm) and narrower width (≤ 10 m) were fabricated, and mounted epi-side down on the copper heatsink, with high...mounted QCLs at a longer wavelength (= 9.3 m). Furthermore, by mounting the device junction-down on the copper heatsink, shorter devices (1.5 mm...a fundamental hexagonal symmetry, a high pillar density of ~ 1011/cm2, and a uniform size of ~24 nm in diameter or smaller over an entire employed

  2. Fabrication characteristics of dry process fuel with a variation of fuel burn-ups

    Energy Technology Data Exchange (ETDEWEB)

    Park, Geun Il; Kim, W. K.; Lee, J. W. [and others

    2004-11-01

    Fabrication characteristics of the dry processed fuel with a variation of fuel burn-ups in a range of 27,300 to 65,000 MWD/tU were experimentally evaluated. Density comparison of powders which were fabricated from oxidation, OREOX and milling processes at same process conditions was performed with a function of fuel burn-ups respectively. The influence of fuel burn-ups on sintering characteristics of dry processed fuel was studied by comparing the density change of sintered pellet as well as green pellet. Weight gain by fuel oxidation to U{sub 3}O{sub 8} showed semi-linear dependence with increasing fuel burn-ups. OREOX powder density increased up to 3.7 g/cm{sup 3} at high burn-up fuel, and the density of milled powder with fuel burn-ups represented almost similar value of 3.2{+-}0.2 g/cm{sup 3}. Also, the green pellet density compacted by 120 MPa decreased smoothly with increasing fuel burn-ups, and the density change of sintered pellet showed the similar trend as green pellet. The sintered density of pellet in a range of 27,000 to 40,000 MWD/tU was found to be more 95% of Theoretical Density(T.D.), but the sintered pellet density fabricated from high burn-up fuel showed a range of 92 % to 93% of T.D.

  3. A Novel Continuous Extrusion Process to Fabricate Wedge-Shaped Light Guide Plates

    Directory of Open Access Journals (Sweden)

    Wen-Tse Hsiao

    2013-01-01

    Full Text Available Backlight modules are key components in thin-film transistor liquid crystal displays (TFT-LCD. Among the components of a backlight module, the light guide plate (LGP plays the most important role controlling the light projected to the eyes of users. A wedge-shaped LGP, with its asymmetrical structure, is usually fabricated by an injection proces, but the fabrication time of this process is long. This study proposes a continuous extrusion process to fabricate wedge-shaped LGPs. This continuous process has advantages for mass production. Besides a T-die and rollers, this system also has an in situ monitor of the melt-bank that forms during the extrusion process, helping control the plate thickness. Results show that the melt bank has a close relationship with the plate thickness. The temperature of the bottom heater and roller was adjusted to reduce the surface deformation of the wedge-shaped plate. This continuous extrusion system can successfully manufacture wedge-shaped LGPs for mass production.

  4. Superconducting Tunnel Junction Arrays for UV Photon Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An innovative method is described for the fabrication of superconducting tunnel junction (STJ) detector arrays offering true "three dimensional" imaging throughout...

  5. Fabrication of advanced electrochemical energy materials using sol-gel processing techniques

    Science.gov (United States)

    Chu, C. T.; Chu, Jay; Zheng, Haixing

    1995-01-01

    Advanced materials play an important role in electrochemical energy devices such as batteries, fuel cells, and electrochemical capacitors. They are being used as both electrodes and electrolytes. Sol-gel processing is a versatile solution technique used in fabrication of ceramic materials with tailored stoichiometry, microstructure, and properties. The application of sol-gel processing in the fabrication of advanced electrochemical energy materials will be presented. The potentials of sol-gel derived materials for electrochemical energy applications will be discussed along with some examples of successful applications. Sol-gel derived metal oxide electrode materials such as V2O5 cathodes have been demonstrated in solid-slate thin film batteries; solid electrolytes materials such as beta-alumina for advanced secondary batteries had been prepared by the sol-gel technique long time ago; and high surface area transition metal compounds for capacitive energy storage applications can also be synthesized with this method.

  6. Quality in the fabrication process; La calidad en los procesos de fabricacion

    Energy Technology Data Exchange (ETDEWEB)

    Romano, A.; Aguirre, F.

    2010-07-01

    Enusa commitment to quality in the manufacture process materializes in the application of the most advanced product quality control technologies such as not-destructive inspection techniques, like artificial vision, X-ray or UT inspection, or process parameter statistical control systems. Quality inspectors are trained and certified by the main National Quality Organizations and receive periodic training under a formal company training program that constantly updates their qualification. Fabrication quality control reliability is based on a strategy that prioritizes redundancy of critical inspection equipment's and inspection personnel knowledge polyvalence. Furthermore, improvement in fabrication quality is obtained by a systematic application of the six sigma methodology where added value is created in projects integrating crosscutting company knowledge, reinforcing the global company vision that the fuel business is based on quality. (Author)

  7. Evaluation of Schottky barrier diodes fabricated directly on processed 4H-SiC(0001) surfaces.

    Science.gov (United States)

    Sano, Yasuhisa; Shirasawa, Yuki; Okamoto, Takeshi; Yamauchi, Kazuto

    2011-04-01

    Silicon carbide (SiC) is a suitable substrate for low-power-consumption power devices and high-temperature applications. However, this material is difficult to machine because of its hardness and chemical inertness, and many machining methods have been studied intensively in recent years. In this paper, we present a simple method to evaluate the electrical properties of the processed surface using the ideal factor n of a Schottky barrier diode (SBD) fabricated directly on the processed surface. Upon comparing the values of n for SBDs fabricated on a damaged SiC surface and a non-damaged SiC surface, we found that there is a significant difference in the dispersion and magnitude of n. Furthermore, by combining this technique with slope etching, we were able to estimate the thickness of the damaged sub-surface layer.

  8. Quantum Junction Solar Cells

    KAUST Repository

    Tang, Jiang

    2012-09-12

    Colloidal quantum dot solids combine convenient solution-processing with quantum size effect tuning, offering avenues to high-efficiency multijunction cells based on a single materials synthesis and processing platform. The highest-performing colloidal quantum dot rectifying devices reported to date have relied on a junction between a quantum-tuned absorber and a bulk material (e.g., TiO 2); however, quantum tuning of the absorber then requires complete redesign of the bulk acceptor, compromising the benefits of facile quantum tuning. Here we report rectifying junctions constructed entirely using inherently band-aligned quantum-tuned materials. Realizing these quantum junction diodes relied upon the creation of an n-type quantum dot solid having a clean bandgap. We combine stable, chemically compatible, high-performance n-type and p-type materials to create the first quantum junction solar cells. We present a family of photovoltaic devices having widely tuned bandgaps of 0.6-1.6 eV that excel where conventional quantum-to-bulk devices fail to perform. Devices having optimal single-junction bandgaps exhibit certified AM1.5 solar power conversion efficiencies of 5.4%. Control over doping in quantum solids, and the successful integration of these materials to form stable quantum junctions, offers a powerful new degree of freedom to colloidal quantum dot optoelectronics. © 2012 American Chemical Society.

  9. Development of a Batch Fabrication Process for Chemical Nanosensors: Recent Advancements at NASA Glenn Research Center

    Science.gov (United States)

    Biaggi-Labiosa, Azlin M.

    2014-01-01

    A major objective in aerospace sensor development is to produce sensors that are small in size, easy to batch fabricate and low in cost, and have low power consumption. Chemical sensors involving nanostructured materials can provide these characteristics as well as the potential for the development of sensor systems with unique properties and improved performance. However, the fabrication and processing of nanostructures for sensor applications currently is limited by the ability to control their location on the sensor platform, which in turn hinders the progress for batch fabrication. This presentation will discuss the following: the development of a novel room temperature methane (CH4) sensor fabricated using porous tin oxide (SnO2) nanorods as the sensing material, the advantages of using nanomaterials in sensor designs, the challenges encountered with the integration of nanostructures into microsensordevices, and the different methods that have been attempted to address these challenges. An approach for the mass production of sensors with nanostructures using a method developed by our group at the NASA Glenn Research Center to control the alignment of nanostructures onto a sensor platform will also be described.

  10. Deep silicon etch for biology MEMS fabrication: review of process parameters influence versus chip design

    Science.gov (United States)

    Magis, T.; Ballerand, S.; Bellemin Comte, A.; Pollet, Olivier

    2013-03-01

    Micro-system for biology is a growing market, especially for micro-fluidic applications (environment and health). Key part for the manufacturing of biology MEMS is the deep silicon etching by plasma to create microstructures. Usual etching process as an alternation of etching and passivation steps is a well-known method for MEMS fabrication, nowadays used in high volume production for devices like sensors and actuators. MEMS for biology applications are very different in design compared to more common micro-systems like accelerometers for instance. Indeed, their design includes on the same chip structures of very diverse size like narrow pillars, large trenches and wide cavities. This makes biology MEMS fabrication very challenging for DRIE, since each type of feature considered individually would require a specific etch process. Furthermore process parameters suited to match specifications on small size features (vertical profile, low sidewall roughness) induce issues and defects on bigger structures (undercut, micro-masking) and vice versa. Thus the process window is constrained leading to trade-offs in process development. In this paper process parameters such as source and platen powers, pressure, etching and passivation gas flows and steps duration were investigated to achieve all requirements. As well interactions between those different factors were characterized at different levels, from individual critical feature up to chip scale and to wafer scale. We will show the plasma process development and tuning to reach all these specifications. We also compared different chambers configurations of our ICP tool (source wafer distance, plasma diffusion) in order to obtain a good combination of hardware and process. With optimized etching we successfully fabricate micro-fluidic devices like micro-pumps.

  11. Focused ion beam processing to fabricate ohmic contact electrodes on a bismuth nanowire for Hall measurements

    OpenAIRE

    Murata, Masayuki; Hasegawa, Yasuhiro

    2013-01-01

    Ohmic contact electrodes for four-wire resistance and Hall measurements were fabricated on an individual single-crystal bismuth nanowire encapsulated in a cylindrical quartz template. Focused ion beam processing was utilized to expose the side surfaces of the bismuth nanowire in the template, and carbon and tungsten electrodes were deposited on the bismuth nanowire in situ to achieve electrical contacts. The temperature dependence of the four-wire resistance was successfully measured for the ...

  12. Optimizing the Dyeing Process of Alkali-Treated Polyester Fabric with Dolu Natural Dye

    OpenAIRE

    M. F. Shahin; Ahmed, R. M.

    2014-01-01

    An attempt has been made to optimize the process of dyeing polyester (PET) fabric with natural dyes. Polyester has been first treated with NaOH solution in order to study its impact on the dyeability to the natural dye. The required and used colour component was extracted from a natural plant, namely: Rhubarb; Rheum officinale. The chemical structure of the used colouring matter is observed to have all the characteristics of a typical disperse dye. The colour strength of PE...

  13. Fabrication of Bio-Nanocomposite Nanofibers Mimicking the Mineralized Hard Tissues via Electrospinning Process

    OpenAIRE

    2010-01-01

    In the present work we demonstrate a powerful technique for fabricating biocompatible and biodegradable PVA/HAp nanocomposite fibers in order to mimic mineralized hard tissues for bone regeneration purpose by applying the electro spinning process. Various techniques, including TEM, HR-TEM, SEM, XRD, DSC, TGA, FTIR spectroscopy were performed to characterize the resulting electrospun PVA/HAp composite nanofibers in comparison with pure PVA and PVA/HAp nanocomposites before electrospinning. Mor...

  14. Characterization of high-purity niobium structures fabricated using the electron beam melting process

    Science.gov (United States)

    Terrazas Najera, Cesar Adrian

    Additive Manufacturing (AM) refers to the varied set of technologies utilized for the fabrication of complex 3D components from digital data in a layer-by-layer fashion. The use of these technologies promises to revolutionize the manufacturing industry. The electron beam melting (EBM) process has been utilized for the fabrication of fully dense near-net-shape components from various metallic materials. This process, catalogued as a powder bed fusion technology, consists of the deposition of thin layers (50 - 120microm) of metallic powder particles which are fused by the use of a high energy electron beam and has been commercialized by Swedish company Arcam AB. Superconducting radio frequency (SRF) cavities are key components that are used in linear accelerators and other light sources for studies of elemental physics. Currently, cavity fabrication is done by employing different forming processes including deep-drawing and spinning. In both of the latter techniques, a feedstock high-purity niobium sheet with a thickness ranging from 3-4 mm is mechanically deformed and shaped into the desired geometry. In this manner, half cavities are formed that are later joined by electron beam welding (EBW). The welding step causes variability in the shape of the cavity and can also introduce impurities at the surface of the weld interface. The processing route and the purity of niobium are also of utmost importance since the presence of impurities such as inclusions or defects can be detrimental for the SRF properties of cavities. The focus of this research was the use of the EBM process in the manufacture of high purity niobium parts with potential SRF applications. Reactor grade niobium was plasma atomized and used as the precursor material for fabrication using EBM. An Arcam A2 system was utilized for the fabrication. The system had all internal components of the fabrication chamber replaced and was cleaned to prevent contamination of niobium powder. A mini-vat, developed at

  15. Development of Infrastructure Facilities for Superconducting RF Cavity Fabrication, Processing and 2 K Characterization at RRCAT

    Science.gov (United States)

    Joshi, S. C.; Raghavendra, S.; Jain, V. K.; Puntambekar, A.; Khare, P.; Dwivedi, J.; Mundra, G.; Kush, P. K.; Shrivastava, P.; Lad, M.; Gupta, P. D.

    2017-02-01

    An extensive infrastructure facility is being established at Raja Ramanna Centre for Advanced Technology (RRCAT) for a proposed 1 GeV, high intensity superconducting proton linac for Indian Spallation Neutron Source. The proton linac will comprise of a large number of superconducting Radio Frequency (SCRF) cavities ranging from low beta spoke resonators to medium and high beta multi-cell elliptical cavities at different RF frequencies. Infrastructure facilities for SCRF cavity fabrication, processing and performance characterization at 2 K are setup to take-up manufacturing of large number of cavities required for future projects of Department of Atomic Energy (DAE). RRCAT is also participating in a DAE’s approved mega project on “Physics and Advanced technology for High intensity Proton Accelerators” under Indian Institutions-Fermilab Collaboration (IIFC). In the R&D phase of IIFC program, a number of high beta, fully dressed multi-cell elliptical SCRF cavities will be developed in collaboration with Fermilab. A dedicated facility for SCRF cavity fabrication, tuning and processing is set up. SCRF cavities developed will be characterized at 2K using a vertical test stand facility, which is already commissioned. A Horizontal Test Stand facility has also been designed and under development for testing a dressed multi-cell SCRF cavity at 2K. The paper presents the infrastructure facilities setup at RRCAT for SCRF cavity fabrication, processing and testing at 2K.

  16. Functionally Graded Aluminum Foam Fabricated by Friction Powder Sintering Process with Traversing Tool

    Science.gov (United States)

    Hangai, Yoshihiko; Morita, Tomoaki; Koyama, Shinji; Kuwazuru, Osamu; Yoshikawa, Nobuhiro

    2016-09-01

    Functionally graded aluminum foam (FG Al foam) is a new class of Al foam in which the pore structure varies over the foam, resulting in corresponding variations in the mechanical properties of the foam. In this study, FG Al foam plates were fabricated by a friction powder sintering (FPS) process with a traversing tool that is based on a previously developed sintering and dissolution process. The variation of the mechanical properties was realized by setting the volume fraction φ of NaCl in the mixture to 60, 70, and 80%. Long FG Al foam plates were fabricated with a length equal to the tool traversing length with φ varying in the tool traversing direction. From x-ray computed tomography observation, it was shown that the density of the Al foam decreased with increasing φ. In contrast, almost uniform pore structures were obtained in each area. According to the results of compression tests on each area, the plateau stress and energy absorption tended to decrease with increasing φ. Therefore, it was shown that FG Al foam plates with varying mechanical properties can be fabricated by the FPS process with the traversing tool.

  17. Micro-structured fiber Bragg gratings: optimization of the fabrication process.

    Science.gov (United States)

    Iadicicco, A; Campopiano, S; Paladino, D; Cutolo, A; Cusano, A

    2007-11-12

    This work has been devoted to present and demonstrate a novel approach for the fabrication of micro-structured fiber Bragg gratings (MSFBGs) with enhanced control of the geometric features and thus of the spectral properties of the final device. The investigated structure relies on the localized stripping of the cladding layer in a well defined region in the middle of the grating structure leading to the formation of a defect state in the spectral response. In order to fully explore the versatility of MSFBGs for sensing and communications applications, a technological assessment of the fabrication process aimed to provide high control of the geometrical features is required. To this aim, here, we demonstrate that the optimization of this device is possible by adopting a fabrication process based on polymeric coatings patterned by high resolution UV laser micromachining tools. The function of the polymeric coating is to act as mask for the HF based chemical etching process responsible for the cladding stripping. Whereas, UV laser micromachining provides a valuable method to accurately pattern the polymeric coating and thus obtain a selective stripping along the grating structure. Here, we experimentally demonstrate the potentiality of the proposed approach to realize reliable and cost efficient MSFBGs enabling the prototyping of advanced photonics devices based on this technology.

  18. Development of a Multi-User Polyimide-MEMS Fabrication Process and its Application to MicroHotplates

    KAUST Repository

    Lizardo, Ernesto B.

    2013-05-08

    Micro-electro-mechanical systems (MEMS) became possible thanks to the silicon based technology used to fabricate integrated circuits. Originally, MEMS fabrication was limited to silicon based techniques and materials, but the expansion of MEMS applications brought the need of a wider catalog of materials, including polymers, now being used to fabricate MEMS. Polyimide is a very attractive polymer for MEMS fabrication due to its high temperature stability compared to other polymers, low coefficient of thermal expansion, low film stress and low cost. The goal of this thesis is to expand the Polyimide usage as structural material for MEMS by the development of a multi-user fabrication process for the integration of this polymer along with multiple metal layers on a silicon substrate. The process also integrates amorphous silicon as sacrificial layer to create free-standing structures. Dry etching is used to release the devices and avoid stiction phenomena. The developed process is used to fabricate platforms for micro-hotplate gas sensors. The fabrication steps for the platforms are described in detail, explaining the process specifics and capabilities. An initial testing of the micro-hotplate is presented. As the process was also used as educational tool, some designs made by students and fabricated with the Polyimide-MEMS process are also presented.

  19. Development, characterization, and applications of high temperature superconductor nanobridge Josephson junctions

    Energy Technology Data Exchange (ETDEWEB)

    Wendt, J.R.; Tigges, C.P.; Hietala, V.M.; Plut, T.A. [Sandia National Labs., Albuquerque, NM (United States); Martens, J.S.; Char, K.; Johansson, M.E. [Conductus, Inc., Sunnyvale, CA (United States)

    1994-03-01

    A well-controlled, high-yield Josephson junction process in high temperature superconductors (HTS) is necessary for the demonstration of ultra-high-speed devices and circuits which exceed the capabilities of conventional electronics. The authors developed nanobridge Josephson junctions in high quality thin-film YBaCuO with dimensions below 100 nm fabricated using electron-beam nanolithography. They characterized this Josephson junction technology for process yield, junction parameter uniformity, and overall applicability for use in high-performance circuits. To facilitate the determination of junction parameters, they developed a measurement technique based on spectral analysis in the range of 90--160 GHz of phase-locked, oscillating arrays of up to 2,450 Josephson junctions. Because of the excellent yield and uniformity of the nanobridge junctions, they successfully applied the junction technology to a wide variety of circuits. These circuits included transmission-line pulse formers and 32 and 64-bit shift registers. The 32-bit shift register was shown to operate at clock speeds near 100 GHz and is believed to be one of the faster and more complex digital circuit demonstrated to date using high temperature superconductor technology.

  20. Scalable, Economical Fabrication Processes for Ultra-Compact Warm-White LEDs

    Energy Technology Data Exchange (ETDEWEB)

    Lowes, Ted [Cree, Inc., Durham, NC (United States)

    2016-01-31

    Conventional warm-white LED component fabrication consists of a large number of sequential steps which are required to incorporate electrical, mechanical, and optical functionality into the component. Each of these steps presents cost and yield challenges which multiply throughout the entire process. Although there has been significant progress in LED fabrication over the last decade, significant advances are needed to enable further reductions in cost per lumen while not sacrificing efficacy or color quality. Cree conducted a focused 18-month program to develop a new low-cost, high-efficiency light emitting diode (LED) architecture enabled by novel large-area parallel processing technologies, reduced number of fabrication steps, and minimized raw materials use. This new scheme is expected to enable ultra-compact LED components exhibiting simultaneously high efficacy and high color quality. By the end of the program, Cree fabricated warm-white LEDs with a room-temperature “instant on” efficacy of >135 lm/W at ~3500K and 90 CRI (when driven at the DOE baseline current density of 35 A/cm2). Cree modified the conventional LED fabrication process flow in a manner that is expected to translate into simultaneously high throughput and yield for ultra-compact packages. Building on its deep expertise in LED wafer fabrication, Cree developed these ultra-compact LEDs to have no compromises in color quality or efficacy compared to their conventional counterparts. Despite their very small size, the LEDs will also be robustly electrically integrated into luminaire systems with the same attach yield as conventional packages. The versatility of the prototype high-efficacy LED architecture will likely benefit solid-state lighting (SSL) luminaire platforms ranging from bulbs to troffers. We anticipate that the prototype LEDs will particularly benefit luminaires with large numbers of distributed compact packages, such as linear and area luminaires (e.g. troffers). The fraction of

  1. Progress in high-efficient solution process organic photovoltaic devices fundamentals, materials, devices and fabrication

    CERN Document Server

    Li, Gang

    2015-01-01

    This book presents an important technique to process organic photovoltaic devices. The basics, materials aspects and manufacturing of photovoltaic devices with solution processing are explained. Solution processable organic solar cells - polymer or solution processable small molecules - have the potential to significantly reduce the costs for solar electricity and energy payback time due to the low material costs for the cells, low cost and fast fabrication processes (ambient, roll-to-roll), high material utilization etc. In addition, organic photovoltaics (OPV) also provides attractive properties like flexibility, colorful displays and transparency which could open new market opportunities. The material and device innovations lead to improved efficiency by 8% for organic photovoltaic solar cells, compared to 4% in 2005. Both academic and industry research have significant interest in the development of this technology. This book gives an overview of the booming technology, focusing on the solution process fo...

  2. Numerical simulation of isothermal chemical vapor infiltration process in fabrication of carbon-carbon composites by finite element method

    Institute of Scientific and Technical Information of China (English)

    李克智; 李贺军; 姜开宇

    2000-01-01

    The chemical vapor infiltration process in fabrication of carbon-carbon composites is highly inefficient and requires long processing time. These limitations add considerably to the cost of fabrication and restrict the application of this material. Efforts have been made to study the CVI process in fabrication of carbon-carbon composites by computer simulation and predict the process parameters, density, porosity, etc. According to the characteristics of CVI process, the basic principle of FEM and mass transport, the finite element model has been established. Incremental finite element equations and the elemental stiffness matrices have been derived for the first time. The finite element program developed by the authors has been used to simulate the ICVI process in fabrication of carbon-carbon composites. Computer color display of simulated results can express the densification and distributions of density and porosity in preform clearly. The influence of process parameters on the densification of prefo

  3. Fabrication of uranium–americium mixed oxide pellet from microsphere precursors: Application of CRMP process

    Energy Technology Data Exchange (ETDEWEB)

    Remy, E. [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Picart, S., E-mail: sebastien.picart@cea.fr [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Delahaye, T. [Fuel Cycle Technology Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Jobelin, I. [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Lebreton, F.; Horlait, D. [Fuel Cycle Technology Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Bisel, I. [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Blanchart, P. [Heterogeneous Materials Research Group, Centre Européen de la Céramique, F-87068 Limoges (France); Ayral, A. [Institut Européen des Membranes, CNRS-ENSCM-UM2, CC47, University Montpellier 2, F-34095 Montpellier cedex 5 (France)

    2014-10-15

    Highlights: • Dust free process for (U,Am)O{sub 2} transmutation target fabrication. • Synthesis of U{sub 0.9}Am{sub 0.1}O{sub 2} mixed oxide microspheres from ion exchange resin. • Fabrication of dense U{sub 0.9}Am{sub 0.1}O{sub 2} pellet with 95% TD from mixed oxide microspheres. - Abstract: Mixed uranium–americium oxides are one of the materials envisaged for Americium Bearing Blankets dedicated to transmutation in fast neutron reactors. Recently, several processes have been developed in order to validate fabrication flowchart in terms of material specifications such as density and homogeneity but also to suggest simplifications for lowering industrial costs and hazards linked to dust generation of highly contaminating and irradiating compounds. This study deals with the application of an innovative route using mixed oxide microspheres obtained from metal loaded resin bead calcination, called Calcined Resin Microsphere Pelletization (CRMP). The synthesis of mixed oxide microsphere precursor of U{sub 0.9}Am{sub 0.1}O{sub 2±δ} is described as well as its characterisation. The use of this free-flowing precursor allows the pressing and sintering of one pellet of U{sub 0.9}Am{sub 0.1}O{sub 2±δ}. The ceramic obtained was characterised and results showed that its microstructure is dense and homogeneous and its density attains 95% of the theoretical density. This study validates the scientific feasibility of the CRMP process applied to the fabrication of uranium and americium-containing materials.

  4. Computer-Aided Process Planning for the Layered Fabrication of Porous Scaffold Matrices

    Science.gov (United States)

    Starly, Binil

    Rapid Prototyping (RP) technology promises to have a tremendous impact on the design and fabrication of porous tissue replacement structures for applications in tissue engineering and regenerative medicine. The layer-by-layer fabrication technology enables the design of patient-specific medical implants and complex structures for diseased tissue replacement strategies. Combined with advancements in imaging modalities and bio-modeling software, physicians can engage themselves in advanced solutions for craniofacial and mandibular reconstruction. For example, prior to the advancement of RP technologies, solid titanium parts used as implants for mandibular reconstruction were fashioned out of molding or CNC-based machining processes (Fig. 3.1). Titanium implants built using this process are often heavy, leading to increased patient discomfort. In addition, the Young's modulus of titanium is almost five times that of healthy cortical bone resulting in stress shielding effects [1,2]. With the advent of CAD/CAM-based tools, the virtual reconstruction of the implants has resulted in significant design improvements. The new generation of implants can be porous, enabling the in-growth of healthy bone tissue for additional implant fixation and stabilization. Newer implants would conform to the external shape of the defect site that is intended to be filled in. More importantly, the effective elastic modulus of the implant can be designed to match that of surrounding tissue. Ideally, the weight of the implant can be designed to equal the weight of the tissue that is being replaced resulting in increased patient comfort. Currently, such porous structures for reconstruction can only be fabricated using RP-based metal fabrication technologies such as Electron Beam Melting (EBM), Selective Laser Sintering (SLS®), and 3D™ Printing processes.

  5. Experiment on the improvement of OREOX process for fabrication of dry recycling nuclear fuel pellets

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Woong Ki; Kim, S. S.; Park, G. I. [and others

    2004-01-01

    The OREOX(Oxidation and REduction of OXide fuel) process has been performed to fabricate dry recycling(DUPIC ; Direct Use of spent PWR fuel In CANDU reactor) nuclear fuel pellets by using spent PWR fuel. Generally, sinterable DUPIC powder has been manufactured from spent PWR fuel pellets by the 3 cycles of oxidation and reduction treatment. The OREOX process is one of the most important processes for DUPIC pellet fabrication. A lot of time more than 37 hours as well as a lot of reaction gas is required to perform 3 cycles of OREOX treatments. In this experiment, 1 cycle OREOX process was adopted to improve the powdering process of DUPIC pellet manufacturing processes. As a result of experiment, the densities of pellets sintered at 1800 .deg. C for 10 hours ranged from 10.15 to 10.22 g/cm{sup 3}(93.8{approx}94.5 % of T.D.). The pellets were sintered again to increase the sintered density. The sintered densities of pellets re-sintered at 1850 .deg. C for 7 hours ranged from 10.27 to 10.33 g/cm{sup 3}(94.9{approx} 95.5 % of T.D)

  6. Direct observation of the carrier transport process in InGaN quantum wells with a pn-junction

    Science.gov (United States)

    Wu, Haiyan; Ma, Ziguang; Jiang, Yang; Wang, Lu; Yang, Haojun; Li, Yangfeng; Zuo, Peng; Jia, Haiqiang; Wang, Wenxin; Zhou, Junming; Liu, Wuming; Chen, Hong

    2016-11-01

    A new mechanism of light-to-electricity conversion that uses InGaN/GaN QWs with a p-n junction is reported. According to the well established light-to-electricity conversion theory, quantum wells (QWs) cannot be used in solar cells and photodetectors because the photogenerated carriers in QWs usually relax to ground energy levels, owing to quantum confinement, and cannot form a photocurrent. We observe directly that more than 95% of the photoexcited carriers escape from InGaN/GaN QWs to generate a photocurrent, indicating that the thermionic emission and tunneling processes proposed previously cannot explain carriers escaping from QWs. We show that photoexcited carriers can escape directly from the QWs when the device is under working conditions. Our finding challenges the current theory and demonstrates a new prospect for developing highly efficient solar cells and photodetectors. Project supported by the National Natural Science Foundation of China (Grant Nos. 11574362, 61210014, and 11374340) and the Innovative Clean-energy Research and Application Program of Beijing Municipal Science and Technology Commission, China (Grant No. Z151100003515001).

  7. Fabrication and characterization of borocarbide thin films grown by in-situ process

    CERN Document Server

    Arisawa, S; Togano, K

    1999-01-01

    We have reported on the fabrication of thin films of YNi sub 2 B sub 2 C for the first time. The process, however, requires the post-annealing at 1050 .deg. C. It is preferable to avoid such a high temperature for practical device applications and we are aiming at establishing an in-situ process at lower temperatures. To obtain films with higher T sub c , it is very important to know the relationship between what we choose as substrates and what we get on them. Three kinds of substrates, polished MgO, unpolished MgO, and polished SrTiO sub 3 were adopted. As for former 2 kinds of substates, superconductive films were successfully fabricated with the T sub c of approx 11K. Further, we discuss the fabrication of thin films of YPd sub 2 B sub 2 C on SrTiO sub 3 substrate. We tried to synthesize the films of the Pd system by RF sputtering technique as well. So far, it is uncertain whether or not the 1221 phase exists in the films. However, the slight reduction of the resistance was observed at 23 K, which is almo...

  8. Ceramic matrix composite article and process of fabricating a ceramic matrix composite article

    Science.gov (United States)

    Cairo, Ronald Robert; DiMascio, Paul Stephen; Parolini, Jason Robert

    2016-01-12

    A ceramic matrix composite article and a process of fabricating a ceramic matrix composite are disclosed. The ceramic matrix composite article includes a matrix distribution pattern formed by a manifold and ceramic matrix composite plies laid up on the matrix distribution pattern, includes the manifold, or a combination thereof. The manifold includes one or more matrix distribution channels operably connected to a delivery interface, the delivery interface configured for providing matrix material to one or more of the ceramic matrix composite plies. The process includes providing the manifold, forming the matrix distribution pattern by transporting the matrix material through the manifold, and contacting the ceramic matrix composite plies with the matrix material.

  9. Innovative fabrication processing of advanced composite materials concepts for primary aircraft structures

    Science.gov (United States)

    Kassapoglou, Christos; Dinicola, Al J.; Chou, Jack C.

    1992-01-01

    The autoclave based THERM-X(sub R) process was evaluated by cocuring complex curved panels with frames and stiffeners. The process was shown to result in composite parts of high quality with good compaction at sharp radius regions and corners of intersecting parts. The structural properties of the postbuckled panels fabricated were found to be equivalent to those of conventionally tooled hand laid-up parts. Significant savings in bagging time over conventional tooling were documented. Structural details such as cocured shear ties and embedded stiffener flanges in the skin were found to suppress failure modes such as failure at corners of intersecting members and skin stiffeners separation.

  10. Control of the fabrication process for the sensors of the CMS silicon strip tracker

    CERN Document Server

    Macchiolo, A

    2004-01-01

    The inner tracking system of the Compact Muon Solenoid experiment at the Large Hadron Collider consists of the world largest Silicon Strip Tracker. A detailed quality assurance program is under way to ensure the full compliance of all delivered sensors with the technical specifications. The focus will be here on the "Process Qualification Control" to monitor the stability of the fabrication process throughout the production phase. A description of the setup in the three laboratories involved (Florence, Strasbourg, Vienna) is given and the results obtained with the first delivered batches are shown.

  11. The Research of Technological Parameters Influence on the Process of Nitinol fabrication and Plastic Deformation

    Directory of Open Access Journals (Sweden)

    Ćubela, D.

    2006-01-01

    Full Text Available Titanium and nickel alloy, with 48 - 55 at. % Ni (rest Ti, named Nitinol has property of thermal and mechanical memory and its properties and application depends strongly on a fabrication processes. Nitinol was produced in semi-industrial conditions. Testing results of the quality of the obtained alloy are related to technological parameters of the production and processing. The aim of this work is to give an answer to the question which technological parameters are most influential and possible for the quality control what kind of corrections regarding literature instructions are needed for successful production of Nitinol for given conditions.

  12. Influence of Fabricating Process on Gas Sensing Properties of ZnO Nanofiber-Based Sensors

    Institute of Scientific and Technical Information of China (English)

    XU Lei; WANG Rui; LIU Yong; DONG Liang

    2011-01-01

    @@ ZnO nanofibers are synthesized by an electrospinning method and characterized by x-ray diffraction(XRD)and scanning electron microscopy(SEM).Two types of gas sensors are fabricated by loading these nanofibers as the sensing materials and their performances are investigated in detail.Compared with the sensors based on traditional ceramic tubes with Au electrodes(traditional sensors), the sensors fabricated by spinning ZnO nanofibers on ceramic planes with Ag-Pd electrodes(plane sensors)exhibit much higher sensing properties.The sensitivity for the plane sensors is about 30 to 100ppm ethanol at 300℃, while the value is only 13 for the traditional sensors.The response and recovery times are about 2 and 3s for the plane sensors and are 3 and 6s for the traditional sensors, respectively.Lower minimum-detection-limit is also found for the plane sensors.These improvements are explained by considering the morphological damage in the fabricating process for traditional sensors.The results suggest that the plane sensors are more suitable to sensing investigation for higher veracity.%ZnO nanofibers are synthesized by an electrospinning method and characterized by x-ray diffraction (XRD)and scanning electron microscopy (SEM). Two types of gas sensors are fabricated by loading these nanofibers as the sensing materials and their performances are investigated in detail. Compared with the sensors based on traditional ceramic tubes with Au electrodes (traditional sensors), the sensors fabricated by spinning ZnO nanofibers on ceramic planes with Ag-Pd electrodes (plane sensors) exhibit much higher sensing properties. The sensitivity for the plane sensors is about 30 to l00ppm ethanol at 300℃, while the value is only 13 for the traditional sensors. The response and recovery times are about 2 and 3s for the plane sensors and are 3 and 6s for the traditional sensors, respectively. Lower minimum-detection-limit is also found for the plane sensors. These improvements are explained

  13. Localized Polymerization Using Single Photon Photoinitiators in Two-photon process for Fabricating Subwavelength Structures

    CERN Document Server

    Ummethala, Govind; Chaudhary, Raghvendra P; Hawal, Suyog; Saxena, Sumit; Shukla, Shobha

    2016-01-01

    Localized polymerization in subwavelength volumes using two photon dyes has now become a well-established method for fabrication of subwavelength structures. Unfortunately, the two photon absorption dyes used in such process are not only expensive but also proprietary. LTPO-L is an inexpensive, easily available single photon photoinitiator and has been used extensively for single photon absorption of UV light for polymerization. These polymerization volumes however are not localized and extend to micron size resolution having limited applications. We have exploited high quantum yield of radicals of LTPO-Lfor absorption of two photons to achieve localized polymerization in subwavelength volumes, much below the diffraction limit. Critical concentration (10wt%) of LTPO-Lin acrylate (Sartomer) was found optimal to achieve subwavelength localized polymerization and has been demonstrated by fabricating 2D/3D complex nanostructures and functional devices such as variable polymeric gratings with nanoscaled subwavelen...

  14. Optimized SU-8 Processing for Low-Cost Microstructures Fabrication without Cleanroom Facilities

    Directory of Open Access Journals (Sweden)

    Vânia C. Pinto

    2014-09-01

    Full Text Available The study and optimization of epoxy-based negative photoresist (SU-8 microstructures through a low-cost process and without the need for cleanroom facility is presented in this paper. It is demonstrated that the Ultraviolet Rays (UV exposure equipment, commonly used in the Printed Circuit Board (PCB industry, can replace the more expensive and less available equipment, as the Mask Aligner that has been used in the last 15 years for SU-8 patterning. Moreover, high transparency masks, printed in a photomask, are used, instead of expensive chromium masks. The fabrication of well-defined SU-8 microstructures with aspect ratios more than 20 is successfully demonstrated with those facilities. The viability of using the gray-scale technology in the photomasks for the fabrication of 3D microstructures is also reported. Moreover, SU-8 microstructures for different applications are shown throughout the paper.

  15. Flexible thin-film polymer waveguides fabricated in an industrial roll-to-roll process.

    Science.gov (United States)

    Bruck, R; Muellner, P; Kataeva, N; Koeck, A; Trassl, S; Rinnerbauer, V; Schmidegg, K; Hainberger, R

    2013-07-01

    The fabrication of flexible low-loss, thin-film, foil-based polymer waveguides with grating couplers employing a high-volume industrial roll-to-roll process is demonstrated. The embossed waveguides feature propagation losses of less than 1 dB/cm (633 nm, TE polarization), bending losses of 0.4-0.8 dB/360° for bending radii as small as 2 mm, and grating coupling efficiencies of up to 25%. In addition, the waveguides possess a thermo-optic coefficient of -1.58×10(-4) 1/°C. The fabricated waveguides are promising candidates for short-distance data communication as well as for sensing applications.

  16. Silicon solar cell process development, fabrication and analyss. Third quarterly report, April-June 1979

    Energy Technology Data Exchange (ETDEWEB)

    Minahan, J.A.

    1979-01-01

    Solar cells have been constructed from various unconventional silicon materials. These cells have been made using conventional aerospace methods. Cells were fabricated by a baseline process and, in some cases, by processes selected to optimize performance of the matrerial. All cells, following fabrication, have been measured on the Spectrolab Solar Simulator at Air Mass Zero and 28/sup 0/C. Conversion efficiencies are based upon total device area. Maximum conversion efficiencies by either baseline or optimized processes were 10.5% for Wacker Silso, 12.0% (BSF) for Westinghouse, Web, 7.2% for Motorola RTR (Baseline), 9.8% for Mobil-Tyco EFG (RF) (Baseline), 11% for Crystal Systems HEM (Baseline), and 11.8% (Baseline) for Hamco continuous CZ material. Most of the silicon materials studied presented few, if any, difficulties in handling during processing and testing. The one exception to this has been the EFG ribbon materials. These wafers were unusually susceptible to fracture during both processing and testing.

  17. Lead-free piezoelectric ceramic coatings fabricated by thermal spray process.

    Science.gov (United States)

    Yao, Kui; Chen, Shuting; Guo, Kun; Tan, Chee Kiang Ivan; Mirshekarloo, Meysam Sharifzadeh; Tay, Francis Eng Hock

    2017-09-04

    The paper starts from a review on the progress in fabrication of piezoelectric ceramic coatings by thermal spray method. For our experimental work, two types of lead-free piezoelectric ceramic coatings, including potassium sodium niobate (KNN)-based and bismuth sodium titanate (BNT)-based, are fabricated by thermal spray process, and their structure, morphology and piezoelectric properties are characterized. Our obtained lead-free ceramic coatings exhibit single phase of perovskite structure, relatively dense morphology, and competitive piezoelectric coefficients. The mechanism of forming the piezoelectric perovskite crystalline phase by thermal spray involving melting-recrystallization process is analyzed in comparison to that of ceramic synthesis through solid state reaction. Suppression of volatile loss and decomposition at high temperature due to the extremely high melting and cooling rate in the thermal spray process, and the impact on the resulting structure are discussed. Significant advantages of the thermal spray method over alternative processing methods for forming piezoelectric ceramic coatings are summarized. The combination of environmentally friendly lead-free compositions and the scalable thermal spray processing method will promote more applications of piezoelectric ceramic coatings for producing distributive sensors and transducers, and forming advanced smart structures and systems.

  18. Recovering probabilities for nucleotide trimming processes for T cell receptor TRA and TRG V-J junctions analyzed with IMGT tools.

    Science.gov (United States)

    Bleakley, Kevin; Lefranc, Marie-Paule; Biau, Gérard

    2008-10-02

    Nucleotides are trimmed from the ends of variable (V), diversity (D) and joining (J) genes during immunoglobulin (IG) and T cell receptor (TR) rearrangements in B cells and T cells of the immune system. This trimming is followed by addition of nucleotides at random, forming the N regions (N for nucleotides) of the V-J and V-D-J junctions. These processes are crucial for creating diversity in the immune response since the number of trimmed nucleotides and the number of added nucleotides vary in each B or T cell. IMGT sequence analysis tools, IMGT/V-QUEST and IMGT/JunctionAnalysis, are able to provide detailed and accurate analysis of the final observed junction nucleotide sequences (tool "output"). However, as trimmed nucleotides can potentially be replaced by identical N region nucleotides during the process, the observed "output" represents a biased estimate of the "true trimming process." A probabilistic approach based on an analysis of the standardized tool "output" is proposed to infer the probability distribution of the "true trimmming process" and to provide plausible biological hypotheses explaining this process. We collated a benchmark dataset of TR alpha (TRA) and TR gamma (TRG) V-J rearranged sequences and junctions analysed with IMGT/V-QUEST and IMGT/JunctionAnalysis, the nucleotide sequence analysis tools from IMGT, the international ImMunoGeneTics information system, http://imgt.cines.fr. The standardized description of the tool output is based on the IMGT-ONTOLOGY axioms and concepts. We propose a simple first-order model that attempts to transform the observed "output" probability distribution into an estimate closer to the "true trimming process" probability distribution. We use this estimate to test the hypothesis that Poisson processes are involved in trimming. This hypothesis was not rejected at standard confidence levels for three of the four trimming processes: TRAV, TRAJ and TRGV. By using trimming of rearranged TR genes as a benchmark, we

  19. Recovering probabilities for nucleotide trimming processes for T cell receptor TRA and TRG V-J junctions analyzed with IMGT tools

    Directory of Open Access Journals (Sweden)

    Lefranc Marie-Paule

    2008-10-01

    Full Text Available Abstract Background Nucleotides are trimmed from the ends of variable (V, diversity (D and joining (J genes during immunoglobulin (IG and T cell receptor (TR rearrangements in B cells and T cells of the immune system. This trimming is followed by addition of nucleotides at random, forming the N regions (N for nucleotides of the V-J and V-D-J junctions. These processes are crucial for creating diversity in the immune response since the number of trimmed nucleotides and the number of added nucleotides vary in each B or T cell. IMGT® sequence analysis tools, IMGT/V-QUEST and IMGT/JunctionAnalysis, are able to provide detailed and accurate analysis of the final observed junction nucleotide sequences (tool "output". However, as trimmed nucleotides can potentially be replaced by identical N region nucleotides during the process, the observed "output" represents a biased estimate of the "true trimming process." Results A probabilistic approach based on an analysis of the standardized tool "output" is proposed to infer the probability distribution of the "true trimmming process" and to provide plausible biological hypotheses explaining this process. We collated a benchmark dataset of TR alpha (TRA and TR gamma (TRG V-J rearranged sequences and junctions analysed with IMGT/V-QUEST and IMGT/JunctionAnalysis, the nucleotide sequence analysis tools from IMGT®, the international ImMunoGeneTics information system®, http://imgt.cines.fr. The standardized description of the tool output is based on the IMGT-ONTOLOGY axioms and concepts. We propose a simple first-order model that attempts to transform the observed "output" probability distribution into an estimate closer to the "true trimming process" probability distribution. We use this estimate to test the hypothesis that Poisson processes are involved in trimming. This hypothesis was not rejected at standard confidence levels for three of the four trimming processes: TRAV, TRAJ and TRGV. Conclusion By

  20. Fabrication and refinement of 6061(p)/6063 aluminum laminate by accumulative roll-bonding (ARB) process

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.-H.; Saito, Y.; Sakai, T.; Utsunomiya, H.; Tsuji, N. [Osaka Univ. (Japan). Dept. of Materials Sciences and Engineering

    2000-07-01

    A 6061 aluminum powder compact is fabricated by sheath rolling method using 6063 aluminum tube as a sheath. Accumulative roll-bonding (ARB) process is applied to the powder compact for improvement of its mechanical properties. The ARB process of 8 cycles is performed at ambient temperature under unlubricated conditions without removing the 6063 sheath. The ARB process of 6061 solid aluminum sheet is also performed for comparison to the 6061 powder compact. The tensile strength of the 6061(p)/6063 laminate increases almost linearly with the number of ARB cycles, and reached the maximum of 465MPa at the 6th cycle, which is 2.3 times higher than that of the initial. The elongation drops abruptly at the 1st cycle, and remains at a constant value (about 7%) from the 2nd cycle to the 5th cycle. Both the strength and the elongation decrease with the number of cycles above the 6th cycle. On the other hand, the tensile strength of 6061 sheet increases with the number of cycles gradually. The increase in tensile strength per cycle is greater in the 6061(p)/6063 laminate than that in the ARBed 6061 sheet. This strengthening is probably due to the fine dispersed oxide which was at first oxide film on aluminum. The ultra-fine grains less than 500nm in diameter are developed in the 6061(p)/6063 laminate fabricated by ARB process. (orig.)

  1. Process chain for fabrication of anisotropic optical functional surfaces on polymer components

    DEFF Research Database (Denmark)

    Li, Dongya; Zhang, Yang; Regi, Francesco

    2017-01-01

    . In order to implement the traceability ofthe manufacturing process, the geometry and dimension of the micro structure on the tool and the replica were assessed viametrological methods. The functionality of the anisotropic surfaces on the polymer replicas were evaluated by a gonioreflectometerand image......This paper aims to introduce a process chain for fabrication of anisotropic optical functional surfaces on polymer products. Thesurface features under investigation are composed of micro serrated ridges. The scope was to maximize the visible contrast betweenhorizontally orthogonal textured surfaces...... from a certain viewing angle. The process chain comprised three steps: tooling, replicationand quality assurance. Tooling was achieved by precision micro milling. Replication processes such as injection moulding, hotembossing, blow moulding, etc. were employed according to the specific type of product...

  2. Optimizing the Dyeing Process of Alkali-Treated Polyester Fabric with Dolu Natural Dye

    Directory of Open Access Journals (Sweden)

    M.F. Shahin

    2014-06-01

    Full Text Available An attempt has been made to optimize the process of dyeing polyester (PET fabric with natural dyes. Polyester has been first treated with NaOH solution in order to study its impact on the dyeability to the natural dye. The required and used colour component was extracted from a natural plant, namely: Rhubarb; Rheum officinale. The chemical structure of the used colouring matter is observed to have all the characteristics of a typical disperse dye. The colour strength of PET fabric was noticed to increase as a result of alkali treatment which may be attributed to the alteration in the hydrophobicity of polyester fibre. The most effective parameters that may affect the dye uptake of the natural dye on alkali-treated PET fabric and the final dyeing properties including dye bath pH, dyeing temperature and time were studied in details. The behaviour of the selected and used natural dye was found to be similar to that of disperse dyes. Addition of salicylic acid to the dye bath accelerated the rate of dyeing and subsequently higher colour strength was attained. Non- ionic dispersing agent was also used to ensure better dyeing uniformity and higher dispersion stability of dye liquor.

  3. Calcium alginate microcapsule generation on a microfluidic system fabricated using the optical disk process

    Science.gov (United States)

    Huang, Keng-Shiang; Liu, Ming-Kai; Wu, Chun-Han; Yen, Yu-Tang; Lin, Yu-Cheng

    2007-08-01

    This paper describes the generation of monodisperse calcium alginate (Ca-alginate) microcapsules on a microfluidic platform using the commercial optical disk process. Our strategy is based on combining the rapid injection molding process for a cross-junction microchannel with the sheath focusing effect to form uniform water-in-oil (w/o) emulsions. These emulsions, consisting of 1.5% (w/v) sodium alginate (Na-alginate), are then dripped into a solution containing 20% (w/v) calcium chloride (CaCl2) creating Ca-alginate microparticles in an efficient manner. This paper demonstrates that the size of Ca-alginate microparticles can be controlled from 20 µm to 50 µm in diameter with a variation of less than 10%, simply by altering the relative sheath/sample flow rate ratio. Experimental data show that for a given fixed dispersed phase flow (sample flow), the emulsion size decreases as the average flow rate of the continuous phase flow (sheath flow) increases. The proposed microfluidic platform is capable of generating relatively uniform emulsions and has the advantages of active control of the emulsion diameter, a simple and low cost process and a high throughput.

  4. Fabrication of conductive polymer nanofibers through SWNT supramolecular functionalization and aqueous solution processing

    Science.gov (United States)

    Naeem, Fahim; Prestayko, Rachel; Saem, Sokunthearath; Nowicki, Lauren; Imit, Mokhtar; Adronov, Alex; Moran-Mirabal, Jose M.

    2015-10-01

    Polymeric thin films and nanostructured composites with excellent electrical properties are required for the development of advanced optoelectronic devices, flexible electronics, wearable sensors, and tissue engineering scaffolds. Because most polymers available for fabrication are insulating, one of the biggest challenges remains the preparation of inexpensive polymer composites with good electrical conductivity. Among the nanomaterials used to enhance composite performance, single walled carbon nanotubes (SWNTs) are ideal due to their unique physical and electrical properties. Yet, a barrier to their widespread application is that they do not readily disperse in solvents traditionally used for polymer processing. In this study, we employed supramolecular functionalization of SWNTs with a conjugated polyelectrolyte as a simple approach to produce stable aqueous nanotube suspensions, that could be effortlessly blended with the polymer poly(ethyleneoxide) (PEO). The homogeneous SWNT:PEO mixtures were used to fabricate conductive thin films and nanofibers with improved conductivities through drop casting and electrospinning. The physical characterization of electrospun nanofibers through Raman spectroscopy and SEM revealed that the SWNTs were uniformly incorporated throughout the composites. The electrical characterization of SWNT:PEO thin films allowed us to assess their conductivity and establish a percolation threshold of 0.1 wt% SWNT. Similarly, measurement of the nanofiber conductivity showed that the electrospinning process improved the contact between nanotube complexes, resulting in conductivities in the S m-1 range with much lower weight loading of SWNTs than their thin film counterparts. The methods reported for the fabrication of conductive nanofibers are simple, inexpensive, and enable SWNT processing in aqueous solutions, and offer great potential for nanofiber use in applications involving flexible electronics, sensing devices, and tissue engineering

  5. Fabrication of conductive polymer nanofibers through SWNT supramolecular functionalization and aqueous solution processing.

    Science.gov (United States)

    Naeem, Fahim; Prestayko, Rachel; Saem, Sokunthearath; Nowicki, Lauren; Imit, Mokhtar; Adronov, Alex; Moran-Mirabal, Jose M

    2015-10-02

    Polymeric thin films and nanostructured composites with excellent electrical properties are required for the development of advanced optoelectronic devices, flexible electronics, wearable sensors, and tissue engineering scaffolds. Because most polymers available for fabrication are insulating, one of the biggest challenges remains the preparation of inexpensive polymer composites with good electrical conductivity. Among the nanomaterials used to enhance composite performance, single walled carbon nanotubes (SWNTs) are ideal due to their unique physical and electrical properties. Yet, a barrier to their widespread application is that they do not readily disperse in solvents traditionally used for polymer processing. In this study, we employed supramolecular functionalization of SWNTs with a conjugated polyelectrolyte as a simple approach to produce stable aqueous nanotube suspensions, that could be effortlessly blended with the polymer poly(ethyleneoxide) (PEO). The homogeneous SWNT:PEO mixtures were used to fabricate conductive thin films and nanofibers with improved conductivities through drop casting and electrospinning. The physical characterization of electrospun nanofibers through Raman spectroscopy and SEM revealed that the SWNTs were uniformly incorporated throughout the composites. The electrical characterization of SWNT:PEO thin films allowed us to assess their conductivity and establish a percolation threshold of 0.1 wt% SWNT. Similarly, measurement of the nanofiber conductivity showed that the electrospinning process improved the contact between nanotube complexes, resulting in conductivities in the S m(-1) range with much lower weight loading of SWNTs than their thin film counterparts. The methods reported for the fabrication of conductive nanofibers are simple, inexpensive, and enable SWNT processing in aqueous solutions, and offer great potential for nanofiber use in applications involving flexible electronics, sensing devices, and tissue engineering

  6. Doping suppression and mobility enhancement of graphene transistors fabricated using an adhesion promoting dry transfer process

    Energy Technology Data Exchange (ETDEWEB)

    Cheol Shin, Woo; Hun Mun, Jeong; Yong Kim, Taek; Choi, Sung-Yool; Jin Cho, Byung, E-mail: bjcho@kaist.edu, E-mail: tskim1@kaist.ac.kr [Department of Electrical Engineering, Graphene Research Center, KAIST, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Yoon, Taeshik; Kim, Taek-Soo, E-mail: bjcho@kaist.edu, E-mail: tskim1@kaist.ac.kr [Department of Mechanical Engineering, Graphene Research Center, KAIST, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

    2013-12-09

    We present the facile dry transfer of graphene synthesized via chemical vapor deposition on copper film to a functional device substrate. High quality uniform dry transfer of graphene to oxidized silicon substrate was achieved by exploiting the beneficial features of a poly(4-vinylphenol) adhesive layer involving a strong adhesion energy to graphene and negligible influence on the electronic and structural properties of graphene. The graphene field effect transistors (FETs) fabricated using the dry transfer process exhibit excellent electrical performance in terms of high FET mobility and low intrinsic doping level, which proves the feasibility of our approach in graphene-based nanoelectronics.

  7. Doping suppression and mobility enhancement of graphene transistors fabricated using an adhesion promoting dry transfer process

    Science.gov (United States)

    Cheol Shin, Woo; Yoon, Taeshik; Hun Mun, Jeong; Yong Kim, Taek; Choi, Sung-Yool; Kim, Taek-Soo; Jin Cho, Byung

    2013-12-01

    We present the facile dry transfer of graphene synthesized via chemical vapor deposition on copper film to a functional device substrate. High quality uniform dry transfer of graphene to oxidized silicon substrate was achieved by exploiting the beneficial features of a poly(4-vinylphenol) adhesive layer involving a strong adhesion energy to graphene and negligible influence on the electronic and structural properties of graphene. The graphene field effect transistors (FETs) fabricated using the dry transfer process exhibit excellent electrical performance in terms of high FET mobility and low intrinsic doping level, which proves the feasibility of our approach in graphene-based nanoelectronics.

  8. Cliché fabrication method using precise roll printing process with 5 um pattern width

    Science.gov (United States)

    Shin, Yejin; Kim, Inyoung; Oh, Dong-Ho; Lee, Taik-Min

    2016-09-01

    Among the printing processes for printed electronic devices, gravure offset and reverse offset method have drawn attention for its fine pattern printing possibility. These printing methods use cliché, which has critical effect on the final product precision and quality. In this research, a novel precise cliché replica method is proposed. It consists of copper sputtering, precise mask pattern printing with 5 um width using reverse offset printing, Ni electroplating, lift-off, etching, and DLC coating. We finally compare the fabricated replica cliché with the original one and print out precise patterns using the replica cliché.

  9. A Novel Technique for Performing PID Susceptibility Screening during the Solar Cell Fabrication Process

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Jaewon; Dahal, Som; Dauksher, Bill; Bowden, Stuart; Tamizhmani, Govindasamy; Hacke, Peter

    2016-11-21

    Various characterization techniques have historically been developed in order to screen potential induced degradation (PID)-susceptible cells, but those techniques require final solar cells. We present a new characterization technique for screening PID-susceptible cells during the cell fabrication process. Illuminated Lock-In Thermography (ILIT) was used to image PID shunting of the cell without metallization and clearly showed PID-affected areas. PID-susceptible cells can be screened by ILIT, and the sample structure can advantageously be simplified as long as the sample has the silicon nitride antireflection coating and an aluminum back surface field.

  10. Mixing in T-junctions

    NARCIS (Netherlands)

    Kok, Jacobus B.W.; van der Wal, S.

    1996-01-01

    The transport processes that are involved in the mixing of two gases in a T-junction mixer are investigated. The turbulent flow field is calculated for the T-junction with the k- turbulence model by FLOW3D. In the mathematical model the transport of species is described with a mixture fraction

  11. An efficient method for monitoring the shunts in silicon solar cells during fabrication processes with infrared imaging

    Institute of Scientific and Technical Information of China (English)

    Zhang Lucheng; Xu Xinxiang; Yang Zhuojian; Sun Xiaopu; Xu Hongyun; Liu Haobin; Shen Hui

    2009-01-01

    , and energy dispersive X-ray spectroscopy. Approaches for diminishing shunts are presented. The methods are beneficial for the optimization of the cell fabrication processes and the improvement of the cell performances.

  12. High-performance fabrication process for 2xnm hole-NIL template production

    Science.gov (United States)

    Yagawa, Keisuke; Suenaga, Machiko; Motokawa, Takeharu; Tanabe, Mana; Ando, Akihiko; Yamanaka, Eiji; Morishita, Keiko; Kanamitsu, Shingo; Saito, Masato; Itoh, Masamitsu

    2016-10-01

    UV nano imprint lithography (UV-NIL) has high-throughput and cost-effective for complex nano-scale patterns and is considered as a candidate for next generation lithography tool. In addition, NIL is the unmagnified lithography and contact transfer technique using template. Therefore, the lithography performance depends greatly on the quality of the template pattern. According to ITRS 2013, the minimum half pitch size of Line and Space (LS) pattern will reach 1x nm level within next five years. On the other hand, in hole pattern, half pith of 2x nm level will be required in five years. Pattern shrink rate of hole pattern size is slower than LS pattern, but shot counts increase explosively compared to LS pattern due to its data volume. Therefore, high throughput and high resolution EB lithography process is required. In previous study, we reported the result of hole patterning on master template which has high resolution resist material and etching process. This study indicated the potential for fabricating 2xnm hole master template [1]. After above study, we aim at fabricating the good quality of 2xnm master template which is assured about defect, CD uniformity(CDU), and Image placement(IP). To product high quality master template, we develop not only high resolution patterning process but also high accuracy quality assurance technology. We report the development progress about hole master template production.

  13. Optimum processing conditions for the fabrication of large, single grain Ag-doped YBCO bulk superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Iida, K. [IRC in Superconductivity and Department of Engineering, University of Cambridge, Cavendish Laboratory 19 JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom)], E-mail: k.iida@ifw-dresden.de; Babu, N.H. [IRC in Superconductivity and Department of Engineering, University of Cambridge, Cavendish Laboratory 19 JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom); BCAST, Brunel University, West London UB8 3PH (United Kingdom); Pathak, S.; Shi, Y.; Yeoh, W.K. [IRC in Superconductivity and Department of Engineering, University of Cambridge, Cavendish Laboratory 19 JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Miyazaki, T. [Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan); SRL-ISTEC, 1-10-13 Shinonome, Koto-ku, Tokyo 135-0062 (Japan); Sakai, N. [SRL-ISTEC, 1-10-13 Shinonome, Koto-ku, Tokyo 135-0062 (Japan); Murakami, M. [Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan); Cardwell, D.A. [IRC in Superconductivity and Department of Engineering, University of Cambridge, Cavendish Laboratory 19 JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom)

    2008-06-15

    A pseudo Time-Temperature-Transformation (TTT) diagram has been constructed for the optimum melt processing conditions for the fabrication of large, single grain Ag-doped Y-Ba-Cu-O (YBCO/Ag) bulk superconductors. The thermal conditions for the formation of homogeneous nuclei have been investigated and the boundary between this region and that for no grain nucleation has been mapped as a function of holding time. YBCO/Ag bulk samples grow typically in the form of single grains when the processing temperature profile lies within the 'no nucleation' region of the pseudo TTT diagram. However, by studying the YBCO/Ag growth process, some samples have been grown in the form of single grains by employing a temperature profile within the homogeneous grain nucleation region of the phase diagram. Such growth may be achieved when the YBCO/Ag phase constitutes the majority of the volume of the pellet before the growth temperature reaches that at the nucleation boundary. A large, single YBCO/Ag grain of diameter 30 mm has been fabricated successfully based on these studies by both cold-seeding and seeded infiltration growth techniques.

  14. Fabrication of a TiO2-P25/(TiO2-P25+TiO2 nanotubes) junction for dye sensitized solar cells

    OpenAIRE

    Nguyen Huy Hao; Gobinda Gyawali; Tohru Sekino; Soo Wohn Lee

    2016-01-01

    The dye sensitized solar cell (DSSC), which converts solar light into electric energy, is expected to be a promising renewable energy source for today's world. In this work, dye sensitized solar cells, one containing a single layer and one containing a double layer, were fabricated. In the double layer DSSC structure, the under-layer was TiO2-P25 film, and the top layer consisted of a mixture of TiO2-P25 and TiO2 nanotubes. The results indicated that the efficiency of the DSSC with the double...

  15. Enhanced performance of wearable piezoelectric nanogenerator fabricated by two-step hydrothermal process

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Yu; Lei, Jixue; Yin, Bing; Zhang, Heqiu; Ji, Jiuyu; Hu, Lizhong, E-mail: lizhongh@dlut.edu.cn [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); The Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024 (China); Yang, Dechao [Department of Electronic Engineering, Dalian Neusoft University of Information, Dalian 116024 (China); Bian, Jiming; Liu, Yanhong; Zhao, Yu; Luo, Yingmin [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

    2014-03-17

    A simple two-step hydrothermal process was proposed for enhancing the performance of the nanogenerator on flexible and wearable terylene-fabric substrate. With this method, a significant enhancement in output voltage of the nanogenerator from ∼10 mV to 7 V was achieved, comparing with the one by conventional one-step process. In addition, another advantage with the devices synthesized by two-step hydrothermal process was that their output voltages are only sensitive to strain rather than strain rate. The devices with a high output voltage have the ability to power common electric devices and will have important applications in flexible electronics and wearable devices.

  16. Photovoltaic characteristics of polymer solar cells fabricated by pre-metered coating process.

    Science.gov (United States)

    Park, Byoungchoo; Han, Mi-Young

    2009-08-03

    We present the results of a study of flat and uniform poly(3-hexylthiophene):methanofullerene bulk-heterojunction photovoltaic (PV) layers that were produced by a simple pre-metered horizontal-dipping process for the fabrication of polymer solar cells (PSCs). It is shown that this process can produce high quality and thin films by utilizing the downstream meniscus of the solution, which can be controlled by adjusting experimental parameters of the gap height and the carrying speed. It is also shown that the produced PV film exhibits high power conversion efficiency of ca. 4.2% with a large active area. It was demonstrated that this pre-metered process for solution coating may be promising for achieving highly efficient, reliable, and large-area PSCs.

  17. Fabrication of an array-like freeform molding tool for UV-replication using a step and repeat process

    Science.gov (United States)

    Dunkel, J.; Wippermann, F.; Brückner, A.; Reimann, A.; Bräuer, A.

    2013-05-01

    Artificial compound eye cameras are a prominent approach of next generation wafer level cameras for consumer electronics due to their lower z-height compared to conventional single aperture objectives. In order to address low cost and high volume markets, their fabrication is based on a wafer level UV-replication process. The image quality of compound eye cameras can be increased significantly by the use of refractive freeform arrays (RFFA) instead of conventional microlens arrays. Therefore, we present the fabrication of a RFFA wafer level molding tool by a step and repeat process for the first time. The surface qualities of the fabricated structures were characterized with a white light interferometer.

  18. Dependency of anti-ferro-magnetic coupling strength on Ru spacer thickness of [Co/Pd]{sub n}-synthetic-anti-ferro-magnetic layer in perpendicular magnetic-tunnel-junctions fabricated on 12-inch TiN electrode wafer

    Energy Technology Data Exchange (ETDEWEB)

    Chae, Kyo-Suk [MRAM Center, Department of Electronics, Hanyang University, Seoul 133-791 (Korea, Republic of); Samsung Electronics Co., Ltd., San #16 Banwol-dong, Hwasung-City, Gyeonggi-Do 445-701 (Korea, Republic of); Shim, Tae-Hun; Park, Jea-Gun, E-mail: parkjgL@hanyang.ac.kr [MRAM Center, Department of Electronics, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2014-07-21

    We investigated the Ru spacer-thickness effect on the anti-ferro-magnetic coupling strength (J{sub ex}) of a [Co/Pd]{sub n}-synthetic-anti-ferro-magnetic layer fabricated with Co{sub 2}Fe{sub 6}B{sub 2}/MgO based perpendicular-magnetic-tunneling-junction spin-valves on 12-in. TiN electrode wafers. J{sub ex} peaked at a certain Ru spacer-thickness: specifically, a J{sub ex} of 0.78 erg/cm{sup 2} at 0.6 nm, satisfying the J{sub ex} criteria for realizing the mass production of terra-bit-level perpendicular-spin-transfer-torque magnetic-random-access-memory. Otherwise, J{sub ex} rapidly degraded when the Ru spacer-thickness was less than or higher than 0.6 nm. As a result, the allowable Ru thickness variation should be controlled less than 0.12 nm to satisfy the J{sub ex} criteria. However, the Ru spacer-thickness did not influence the tunneling-magneto-resistance (TMR) and resistance-area (RA) of the perpendicular-magnetic-tunneling-junction (p-MTJ) spin-valves since the Ru spacer in the synthetic-anti-ferro-magnetic layer mainly affects the anti-ferro-magnetic coupling efficiency rather than the crystalline linearity of the Co{sub 2}Fe{sub 6}B{sub 2} free layer/MgO tunneling barrier/Co{sub 2}Fe{sub 6}B{sub 2} pinned layer, although Co{sub 2}Fe{sub 6}B{sub 2}/MgO based p-MTJ spin-valves ex-situ annealed at 275 °C achieved a TMR of ∼70% at a RA of ∼20 Ω μm{sup 2}.

  19. Continuously graded extruded polymer composites for energetic applications fabricated using twin-screw extrusion processing technology

    Science.gov (United States)

    Gallant, Frederick M.

    A novel method of fabricating functionally graded extruded composite materials is proposed for propellant applications using the technology of continuous processing with a Twin-Screw Extruder. The method is applied to the manufacturing of grains for solid rocket motors in an end-burning configuration with an axial gradient in ammonium perchlorate volume fraction and relative coarse/fine particle size distributions. The fabrication of functionally graded extruded polymer composites with either inert or energetic ingredients has yet to be investigated. The lack of knowledge concerning the processing of these novel materials has necessitated that a number of research issues be addressed. Of primary concern is characterizing and modeling the relationship between the extruder screw geometry, transient processing conditions, and the gradient architecture that evolves in the extruder. Recent interpretations of the Residence Time Distributions (RTDs) and Residence Volume Distributions (RVDs) for polymer composites in the TSE are used to develop new process models for predicting gradient architectures in the direction of extrusion. An approach is developed for characterizing the sections of the extrudate using optical, mechanical, and compositional analysis to determine the gradient architectures. The effects of processing on the burning rate properties of extruded energetic polymer composites are characterized for homogeneous formulations over a range of compositions to determine realistic gradient architectures for solid rocket motor applications. The new process models and burning rate properties that have been characterized in this research effort will be the basis for an inverse design procedure that is capable of determining gradient architectures for grains in solid rocket motors that possess tailored burning rate distributions that conform to user-defined performance specifications.

  20. Micro-Thermoelectric Generation Modules Fabricated with Low-Cost Mechanical Machining Processes

    Science.gov (United States)

    Liu, Dawei; Jin, A. J.; Peng, Wenbo; Li, Qiming; Gao, Hu; Zhu, Lianjun; Li, Fu; Zhu, Zhixiang

    2017-05-01

    Micro/small-scale thermoelectric generation modules are able to produce continuous, noise-free and reliable electricity power using low temperature differences that widely exist in nature or industry. These advantages bring them great application prospects in the fields of remote monitoring, microelectronics/micro-electromechanical systems (MEMS), medical apparatus and smart management system, which often require a power source free of maintenance and vibration. In this work, a prototypical thermoelectric module (12 mm × 12 mm × 0.8 mm) with 15 pairs of micro-scale thermoelectric legs (0.2 mm in width and 0.6 mm in height for each leg) is fabricated using a low-cost mechanical machining process. In this process, cutting and polishing are the main methods for the preparation of thermoelectric pairs from commercial polycrystalline materials and for the fabrication of electrode patterns. The as-fabricated module is tested for its power generation properties with the hot side heated by an electrical heater and the cold side by cold air. With the heater temperature of 375 K, the thermoelectric potential is about 9.1 mV, the short circuit current is about 14.5 mA, and the maximum output power is about 32.8 μW. The finite element method is applied to analyze the heat transfer of the module during our test. The temperature difference and heat flux are simulated, according to which the output powers at different temperatures are calculated, and the result is relatively consistent compared to the test results.

  1. Fabrication of channel waveguides from sol-gel-processed polyvinylpyrrolidone/ SiO(2) composite materials.

    Science.gov (United States)

    Yoshida, M; Prasad, P N

    1996-03-20

    Sol-gel-processed composite materials of polyvinylpyrrolidone (PVP) and SiO(2) were studied for optical waveguide applications. PVP is a polymer that can be crosslinked, so it is expected to have high thermal stability after crosslinking. However, thermal crosslinking and thermal decomposition of pure PVP take place around the same temperature, 200 °C, therefore pure PVP had a high optical propagation loss as a result of the absorption of the decomposed molecules after crosslinking. The incorporation of sol-gel-processed SiO(2) prevented the thermal decomposition of PVP and provided remarkably low optical propagation losses. The PVP/SiO(2)composite material also produced thick (>2-µm) crack-free films when the PVP concentration was 50% or higher. An optical propagation loss of 0.2 dB/cm was achieved at 633 nm in the 50% PVP/SiO(2) composite planar waveguide. Several aspects of the thermal stability of the waveguides were evaluated. The slab waveguide was then used for fabrication of channel waveguides with a selective laser-densification technique. This technique used metal lines fabricated with photolithography on the slab waveguide as a light absorbent, and these metal lines were heated by an Ar laser. The resultant channel waveguide had an optical propagation loss of 0.9 dB/ cm at 633 nm. This technique provides lower absorption loss and scattering loss compared with the direct laser-densification technique, which uses UV lasers, and produces narrow waveguides that are difficult to fabricate with a CO(2) laser.

  2. Micro-Thermoelectric Generation Modules Fabricated with Low-Cost Mechanical Machining Processes

    Science.gov (United States)

    Liu, Dawei; Jin, A. J.; Peng, Wenbo; Li, Qiming; Gao, Hu; Zhu, Lianjun; Li, Fu; Zhu, Zhixiang

    2016-11-01

    Micro/small-scale thermoelectric generation modules are able to produce continuous, noise-free and reliable electricity power using low temperature differences that widely exist in nature or industry. These advantages bring them great application prospects in the fields of remote monitoring, microelectronics/micro-electromechanical systems (MEMS), medical apparatus and smart management system, which often require a power source free of maintenance and vibration. In this work, a prototypical thermoelectric module (12 mm × 12 mm × 0.8 mm) with 15 pairs of micro-scale thermoelectric legs (0.2 mm in width and 0.6 mm in height for each leg) is fabricated using a low-cost mechanical machining process. In this process, cutting and polishing are the main methods for the preparation of thermoelectric pairs from commercial polycrystalline materials and for the fabrication of electrode patterns. The as-fabricated module is tested for its power generation properties with the hot side heated by an electrical heater and the cold side by cold air. With the heater temperature of 375 K, the thermoelectric potential is about 9.1 mV, the short circuit current is about 14.5 mA, and the maximum output power is about 32.8 μW. The finite element method is applied to analyze the heat transfer of the module during our test. The temperature difference and heat flux are simulated, according to which the output powers at different temperatures are calculated, and the result is relatively consistent compared to the test results.

  3. Laser technology of SNOM-tips fabrication: process diagnostics, processing, and testing

    Science.gov (United States)

    Veiko, Vadim P.; Kalachev, Alexey N.; Kaporsky, Lev N.; Volkov, Sergey A.; Voznesensky, Nikolay B.

    2003-09-01

    Basic principles of laser assisted process of fiber etching for scanning near-field optical (SNO) probes formation and control technique are presented. The thermal and temporal regimes are considered in order to provide stable reproducibility and high quality of a tapered end of the optical fiber. Problems of adequate definition of the scanning imaging properties of a SNO probe are discussed. Thus an optical method of far-field registration and processing together with a new autoelectric emission method are considered for solution of the task of a subwavelength SNO probe aperture measurement and estimation of its apparatus function.

  4. A versatile MEMS bimorph actuator with large vertical displacement and high resolution: Design and fabrication process

    Science.gov (United States)

    Rangra, Aarushee; Maninder, K.; Soni, Shilpi; Rangra, K. J.

    2016-04-01

    This paper presents design, simulation results and envisaged fabrication process for a versatile MEMS bimorph actuator with large out of plane displacement and high resolution. A comparative study of mechanical, thermal and electrical response of the micro-actuator is presented by using two well-known MEMS simulation tools. The bimorph structure measuring 700 × 1280 mm2 is fully integrable with CMOS fabrication process. It is indented for tunable filter applications where the precise vertical motion of the payload, the top metallic electrode anchored rigidly to bimorph `springs' spans the vertical range of 250-300 microns with submicron resolution. Each bimorph spring resembles a hair pin structure and is composed of materials with large difference in thermal expansion coefficients e.g. electroplated gold and polysilicon for optimal out-of-the plane deflection. The novel structure can also be configured for analog micro-mirror based optical and IR spectroscopy applications by controlling the actuation bias and top electrode surface parameters.

  5. Microstructure and microhardness of AA1050/TiC surface composite fabricated using friction stir processing

    Indian Academy of Sciences (India)

    A Thangarasu; N Murugan; I Dinaharan; S J Vijay

    2012-10-01

    Friction stir processing (FSP) has been developed by several researchersto produce an upper surface modification of metallic materials. The fabrication of TiC particulate $(\\sim 2 \\mu m)$ reinforced aluminum matrix composite (AMC) using FSP is studied in this paper. The measured content of TiC powders were compacted into a groove of 0.5 mm × 5.5 mm. A single pass FSP was carried out using a tool rotational speed of 1600 rpm, processing speed of 60 mm/min and axial force of 10 kN. A tool made of HCHCr steel, oil hardened to 62 HRC, having a cylindrical profile was used in this study. The microstructure and microhardness of the fabricated AMC were analysed. Scanning Electron Microscope (SEM) micrographs revealed a uniform distribution of TiC particles which were well-bonded to the matrix alloy. The hardness of the AMC increased by 45% higher than that of the matrix alloy.

  6. Fabrication of Coupling Structure and Composite Properties by Electro-brush Plating and Laser Processing

    Directory of Open Access Journals (Sweden)

    LI Jing

    2016-12-01

    Full Text Available To obtain a superhydrophobic aluminum alloy surface, a kind of special coupling structure was fabricated on the aluminum alloy surface by a couple ways which was electro-brush plating combined with laser processing. The surface has excellent anti-adhesion and corrosion resistance property. The contact angle can reach as high as 155.1°, while the sliding angle less than 5.6°. The morphological feature, chemical structures, and wettability of resultant surfaces were characterized by scanning electronic microscope (SEM, X-ray diffraction (XRD and water contact angle measurements. The surface corrosion resistance was researched by a corrosion resistance experiment. The results show that surface consists of micro-scale grooves and like-cauliflower mastoids, the grooves in a regular arrangement with mastoid structures for a coupling structure on the surface. The special coupling structure makes the surface already have superhydrophobicity. The wettability of the surface changes from hydrophilicity to superhydrophobicity. There have no peaks from other phases can be detected between electro-brush plating surface and aluminum alloy substrates. The peak intensity is changed by laser processing, and the organization structure of the material is further refined. The corrosion resistance of the surface that is fabricated by couple ways improves.

  7. Processing and Characterization of PETI Composites Fabricated by High Temperature VARTM

    Science.gov (United States)

    Ghose, Sayata; Cano, Roberto J.; Watson, Kent A.; Britton, Sean M.; Jensen, Brian J.; Connell, John W.; Smith, Joseph G.; Loos, Alfred C.; Heider, Dirk

    2011-01-01

    The use of composites as primary structures on aerospace vehicles has increased dramatically over the past decade. As these advanced structures increase in size and complexity, their production costs have grown significantly. A major contributor to these manufacturing costs is the requirement of elevated processing pressures, during the thermal cure, to create fully consolidated composites. For certain composite parts, high temperature vacuum assisted resin transfer molding (HT-VARTM) can offer reduced fabrication costs compared to conventional autoclave techniques. The process has been successfully used with phenylethynyl terminated imide (PETI) resins developed by NASA LaRC. In the current study, two PETI resins, LARC(TradeMark) PETI-330 and LARC(TradeMark) PETI-8 have been used to make test specimens using HT-VARTM. Based on previous work at NASA LaRC, larger panels with a quasi-isotropic lay-up were fabricated. The resultant composite specimens exhibited void contents VARTM. The results of this work are presented herein.

  8. Fabrication of a stainless steel microchannel microcombustor using a lamination process

    Science.gov (United States)

    Matson, Dean W.; Martin, Peter M.; Tonkovich, Anna Lee Y.; Roberts, Gary L.

    1998-09-01

    Microscale chemical devices have potential application as fuel processors to produce high purity hydrogen for PEM fuel cells from hydrocarbon fuels such as methane, methanol, ethanol, or gasoline. The fabrication of a novel stainless steel catalytic microcombustor/reactor suitable for use to high temperatures is described. The device consisted of three parts to accommodate catalyst loading: a laminated reactor body, a laminated combustor, and a solid cover plate. The laminated components were produced using stacks of photochemically machined stainless steel shims. When formed into solid leak-tight components using a diffusion bonding process, the laminated parts were designed to contain a complex series of internal gas-flow microchannels that could not be produced in a solid metal block by other fabrication methods. Included within the reactor body was an array of heat exchanger microchannels 250 microns wide and 5000 microns deep that were designed to extract heat from the catalytic reaction region and pre-heat the reactant gases. Catalytic combustion of hydrogen or hydrocarbon fuel occurred in a separate laminated combustor plate. The laminated combustor/reactor design has potential for use in a variety of chemical processing and heat exchanger applications.

  9. Development and demonstration of manufacturing processes for fabricating graphite/PMR-15 polyimide structural elements. [space shuttle aft body flap

    Science.gov (United States)

    Sheppard, C. H.; Hoggatt, J. T.; Symonds, W. A.

    1979-01-01

    The processing requirements for graphite/PMR-15 polyimide composites developed to demonstrate the structural integrity of polyimide composite structural elements at temperatures up to 589K (600 F) are described. Major tasks included: quality assurance development; materials and process development; specification verification; flat panel fabrication; stiffened panel fabrication; honeycomb panel fabrication; chopped fiber moldings; and demonstration component fabrication. Materials, processing, and quality assurance documents were prepared from experimentally derived data. Structural elements consisting of flat panels, corrugated stiffeners, I-beams, hat stiffeners, honeycomb panels, and chopped fiber moldings were made and tested. Property data from 219K (-65 F) to 589K (600 F) were obtained. All elements were made in a production environment. The size of each element was sufficient to insure production capability and structural component applicability. Problems associated with adhesive bonding, laminate and structural element analysis, material variability, and test methods were addressed.

  10. Development and demonstration of manufacturing processes for fabricating graphite/PMR-15 polyimide structural elements. [space shuttle aft body flap

    Science.gov (United States)

    Sheppard, C. H.; Hoggatt, J. T.; Symonds, W. A.

    1979-01-01

    The processing requirements for graphite/PMR-15 polyimide composites developed to demonstrate the structural integrity of polyimide composite structural elements at temperatures up to 589K (600 F) are described. Major tasks included: quality assurance development; materials and process development; specification verification; flat panel fabrication; stiffened panel fabrication; honeycomb panel fabrication; chopped fiber moldings; and demonstration component fabrication. Materials, processing, and quality assurance documents were prepared from experimentally derived data. Structural elements consisting of flat panels, corrugated stiffeners, I-beams, hat stiffeners, honeycomb panels, and chopped fiber moldings were made and tested. Property data from 219K (-65 F) to 589K (600 F) were obtained. All elements were made in a production environment. The size of each element was sufficient to insure production capability and structural component applicability. Problems associated with adhesive bonding, laminate and structural element analysis, material variability, and test methods were addressed.

  11. Measure Guideline: Optimizing the Configuration of Flexible Duct Junction Boxes

    Energy Technology Data Exchange (ETDEWEB)

    Beach, R.; Burdick, A.

    2014-03-01

    This measure guideline offers additional recommendations to heating, ventilation, and air conditioning (HVAC) system designers for optimizing flexible duct, constant-volume HVAC systems using junction boxes within Air Conditioning Contractors of America (ACCA) Manual D guidance (Rutkowski, H. Manual D -- Residential Duct Systems, 3rd edition, Version 1.00. Arlington, VA: Air Conditioning Contractors of America, 2009.). IBACOS used computational fluid dynamics software to explore and develop guidance to better control the airflow effects of factors that may impact pressure losses within junction boxes among various design configurations (Beach, R., Prahl, D., and Lange, R. CFD Analysis of Flexible Duct Junction Box Design. Golden, CO: National Renewable Energy Laboratory, submitted for publication 2013). These recommendations can help to ensure that a system aligns more closely with the design and the occupants' comfort expectations. Specifically, the recommendations described herein show how to configure a rectangular box with four outlets, a triangular box with three outlets, metal wyes with two outlets, and multiple configurations for more than four outlets. Designers of HVAC systems, contractors who are fabricating junction boxes on site, and anyone using the ACCA Manual D process for sizing duct runs will find this measure guideline invaluable for more accurately minimizing pressure losses when using junction boxes with flexible ducts.

  12. Optimized process parameters for fabricating metal particles reinforced 5083 Al composite by friction stir processing.

    Science.gov (United States)

    Bauri, Ranjit; Yadav, Devinder; Shyam Kumar, C N; Janaki Ram, G D

    2015-12-01

    Metal matrix composites (MMCs) exhibit improved strength but suffer from low ductility. Metal particles reinforcement can be an alternative to retain the ductility in MMCs (Bauri and Yadav, 2010; Thakur and Gupta, 2007) [1,2]. However, processing such composites by conventional routes is difficult. The data presented here relates to friction stir processing (FSP) that was used to process metal particles reinforced aluminum matrix composites. The data is the processing parameters, rotation and traverse speeds, which were optimized to incorporate Ni particles. A wide range of parameters covering tool rotation speeds from 1000 rpm to 1800 rpm and a range of traverse speeds from 6 mm/min to 24 mm/min were explored in order to get a defect free stir zone and uniform distribution of particles. The right combination of rotation and traverse speed was found from these experiments. Both as-received coarse particles (70 μm) and ball-milled finer particles (10 μm) were incorporated in the Al matrix using the optimized parameters.

  13. Optimized process parameters for fabricating metal particles reinforced 5083 Al composite by friction stir processing

    Directory of Open Access Journals (Sweden)

    Ranjit Bauri

    2015-12-01

    Full Text Available Metal matrix composites (MMCs exhibit improved strength but suffer from low ductility. Metal particles reinforcement can be an alternative to retain the ductility in MMCs (Bauri and Yadav, 2010; Thakur and Gupta, 2007 [1,2]. However, processing such composites by conventional routes is difficult. The data presented here relates to friction stir processing (FSP that was used to process metal particles reinforced aluminum matrix composites. The data is the processing parameters, rotation and traverse speeds, which were optimized to incorporate Ni particles. A wide range of parameters covering tool rotation speeds from 1000 rpm to 1800 rpm and a range of traverse speeds from 6 mm/min to 24 mm/min were explored in order to get a defect free stir zone and uniform distribution of particles. The right combination of rotation and traverse speed was found from these experiments. Both as-received coarse particles (70 μm and ball-milled finer particles (10 μm were incorporated in the Al matrix using the optimized parameters.

  14. Ground-water flow and contaminant transport at a radioactive-materials processing site, Wood River Junction, Rhode Island

    Science.gov (United States)

    Ryan, Barbara J.; Kipp, Kenneth L.

    1997-01-01

    Liquid wastes from an enriched-uranium cold-scrap recovery plant at Wood River Junction, Rhode Island, were discharged to the environment through evaporation ponds and trenches from 1966 through 1980. Leakage from the ponds and trenches resulted in a plume of contaminated ground water extending northwestward to the Pawcatuck River through a highly permeable sand and gravel aquifer of glacial origin.

  15. The human myotendinous junction

    DEFF Research Database (Denmark)

    Knudsen, A B; Larsen, M; Mackey, Abigail

    2015-01-01

    The myotendinous junction (MTJ) is a specialized structure in the musculotendinous system, where force is transmitted from muscle to tendon. Animal models have shown that the MTJ takes form of tendon finger-like processes merging with muscle tissue. The human MTJ is largely unknown and has never ...

  16. Fabrication of metal matrix composite by semi-solid powder processing

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yufeng [Iowa State Univ., Ames, IA (United States)

    2011-01-01

    Various metal matrix composites (MMCs) are widely used in the automotive, aerospace and electrical industries due to their capability and flexibility in improving the mechanical, thermal and electrical properties of a component. However, current manufacturing technologies may suffer from insufficient process stability and reliability and inadequate economic efficiency and may not be able to satisfy the increasing demands placed on MMCs. Semi-solid powder processing (SPP), a technology that combines traditional powder metallurgy and semi-solid forming methods, has potential to produce MMCs with low cost and high efficiency. In this work, the analytical study and experimental investigation of SPP on the fabrication of MMCs were explored. An analytical model was developed to understand the deformation mechanism of the powder compact in the semi-solid state. The densification behavior of the Al6061 and SiC powder mixtures was investigated with different liquid fractions and SiC volume fractions. The limits of SPP were analyzed in terms of reinforcement phase loading and its impact on the composite microstructure. To explore adoption of new materials, carbon nanotube (CNT) was investigated as a reinforcing material in aluminum matrix using SPP. The process was successfully modeled for the mono-phase powder (Al6061) compaction and the density and density distribution were predicted. The deformation mechanism at low and high liquid fractions was discussed. In addition, the compaction behavior of the ceramic-metal powder mixture was understood, and the SiC loading limit was identified by parametric study. For the fabrication of CNT reinforced Al6061 composite, the mechanical alloying of Al6061-CNT powders was first investigated. A mathematical model was developed to predict the CNT length change during the mechanical alloying process. The effects of mechanical alloying time and processing temperature during SPP were studied on the mechanical, microstructural and

  17. A post-fabrication selective magnetic annealing technique in standard MEMS processes

    Science.gov (United States)

    Mohammadi, A.; Karmakar, N. C.; Yuce, M. R.

    2016-11-01

    A selective electrothermal magnetic annealing technique is introduced that provides programming capabilities for mechanical micro-resonators. In the proposed approach, the magnetic properties of resonators can be locally tuned in a post-fabrication batch-compatible process step. A prototype is implemented in a standard microfabrication process, where resonating ferromagnetic elements are suspended on top of a polysilicon resistive heater. The ferromagnetic elements consist of electroplated Nickel (Ni) with minor Iron (Fe) impurities. The electro-thermo-mechanical heating phenomenon is simulated for design purposes. The magnetization of micro-resonators with and without magnetic annealing is measured. The resulting magnetic property enhancement is illustrated by hysteresis (M-H) loop variations.

  18. Dielectric microwave absorbing material processed by impregnation of carbon fiber fabric with polyaniline

    Directory of Open Access Journals (Sweden)

    Luiza de Castro Folgueras

    2007-03-01

    Full Text Available It is a known fact that the adequate combination of components and experimental conditions may produce materials with specific requirements. This study presents the effect of carbon fiber fabric impregnation with polyaniline conducting polymer aiming at the radar absorbing material processing. The experiments consider the sample preparation with one and two impregnations. The prepared samples were evaluated by reflectivity measurements, in the frequency range of 8-12 GHz and scanning electron microscopy analyses. The correlation of the results shows that the quantity of impregnated material influences the performance of the processed microwave absorber. This study shows that the proposed experimental route provides flexible absorbers with absorption values of the incident radiation close to 87%.

  19. Concurrent engineering solution for the design of ship and offshore bracket parts and fabrication process

    Science.gov (United States)

    Kim, Tae-Won; Lim, Sang-Sub; Seok, Ho-Hyun; Kang, Chung-Gil

    2013-09-01

    Brackets in ships and offshore structures are added structures that can endure stress concentrations. In this study, a concurrent engineering solution was proposed, and a high strength low carbon cast steel alloy applicable to offshore structures was designed and developed. The yield strength and ultimate tensile strength of the designed steel were 480 and 600 MPa, respectively. The carbon equivalent of the steel was 0.446 with a weld crack susceptibility index of 0.219. The optimal structural design of the brackets for offshore structures was evaluated using ANSYS commercial software. The possibility of replacing an assembly of conventional built-up brackets with a single casting bulb bracket was verified. The casting process was simulated using MAGMAsoft commercial software, and a casting fabrication process was designed. For the proposed bulb bracket, it was possible to reduce the size and weight by approximately 30% and 50%, respectively, compared to the conventional type of bracket.

  20. Numerically design the injection process parameters of parts fabricated with ramie fiber reinforced green composites

    Science.gov (United States)

    Chen, L. P.; He, L. P.; Chen, D. C.; Lu, G.; Li, W. J.; Yuan, J. M.

    2017-01-01

    The warpage deformation plays an important role on the performance of automobile interior components fabricated with natural fiber reinforced composites. The present work investigated the influence of process parameters on the warpage behavior of A pillar trim made of ramie fiber (RF) reinforced polypropylene (PP) composites (RF/PP) via numerical simulation with orthogonal experiment method and range analysis. The results indicated that fiber addition and packing pressure were the most important factors affecting warpage. The A pillar trim can achieved the minimum warpage value as of 2.124 mm under the optimum parameters. The optimal process parameters are: 70% percent of the default value of injection pressure for the packing pressure, 20 wt% for the fiber addition, 185 °C for the melt °C for the mold temperature, 7 s for the filling time and 17 s for the packing time.

  1. Fabrication of ceramic layer on an Al-Si alloy by MAO process

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The MAO (Micro-Arc Oxidation) process is applied to a eutectic Al-Si alloy (Al-12.0%Si-l.0%Cu-0.9%Mg(mass fraction)). The oxide ceramic layer was fabricated with about 220 μm thickness and 3000 Hv micro-hardness. ByXRD (X-ray diffractometry) and DSC (differential scanning calorimetry) analyses, the oxide layer consists of amorphousAl2O3, which is distinct from the results reported by the other researchers. The SEM photographs of such layer show that thelayer is fixed tightly on the substrate alloy. So this alloy can be used in the high temperature and friction environment after itis treated with such process.

  2. Fabrication and characterization of solution processed vertically aligned ZnO microrods

    Energy Technology Data Exchange (ETDEWEB)

    Gadallah, A.-S., E-mail: agadallah@niles.edu.eg [Laboratoire de Nanotechnologie et d’Instrumentation Optique, Institut Charles Delaunay, CNRS UMR 6279, Université de Technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes Cedex (France); Department of Laser Sciences and Interactions, National Institute of Laser Enhanced Sciences, Cairo University, 12613 Giza (Egypt)

    2014-08-30

    Simple and effective cost high quality vertically aligned densely packed ZnO microrods have been prepared using solution processed two-step deposition process, specifically sol–gel spin coating combined with chemical bath deposition. X-ray diffraction pattern and scanning electron microscope show that there has been preferential crystal orientation along c-axis and the growth of the microrods has occurred normal to the glass substrate and the facets of the these microrods are hexagons. Photoluminescence measurements showed an emission band in the UV region and another weak band in the visible region with the emission intensity of UV band grows superlinearly with the excitation intensity. The film shows an electrical resistivity of 136 Ω cm as evaluated from four-point probe method. The fabricated film has been used as UV detector through Au/SiO{sub 2}/ZnO structure on glass substrate as the structure shows higher current under illumination compared to without illumination.

  3. Photovoltaic characteristics of each subcell evaluated in situ in a triple-junction solar cell

    Science.gov (United States)

    Huang, Tzu-Hsuan; Lo, Hao; Lo, Chieh; Wu, Meng-Chyi; Lour, Wen-Shiung

    2016-12-01

    New manufacturing processes were proposed to evaluate important photovoltaic properties of each subcell in an InGaP/InGaAs/Ge triple-junction solar cell. In addition to the triple-junction cell, an InGaAs/Ge double-junction cell and a Ge single-junction cell were also fabricated and employed for evaluation. The key merit of the double-junction cell is that semiconductor layers of forming InGaP top subcell are retained as a dummy top subcell. Thus, the InGaAs middle subcells in both triple- and double-junction cells will receive the same light spectrum. Similarly, the Ge single-junction cell is fabricated with dummy top and middle subcells as light filters. Open-circuit voltage, short-circuit current, conversion efficiency, and current mismatched ratio were measured for evaluating and optimizing each subcell. It is found that Open-circuit voltages are 1.295, 0.967, and 0.212 V for the InGaP, InGaAs, and Ge subcells with temperature coefficients of -2.5, -1.99, and -1.87 mV/°C. Thus the Ge subcell no longer acts a real solar cell at temperature over ∼140 °C. Besides, effect of ambient temperature on short circuit currents of all as-fabricated solar cells is not relevant. The current mismatched ratios are 18.6-20% at temperature ranged from 25 °C to 80 °C. A low efficiency of ∼18.7% is due partly to the poor current match. However, the processing concept proposed is useful as a method of matching currents among the subcells.

  4. Junction size dependence of ferroelectric properties in e-beam patterned BaTiO{sub 3} ferroelectric tunnel junctions

    Energy Technology Data Exchange (ETDEWEB)

    Singh, A. V.; Gupta, A. [Center for Materials for Information Technology, The University of Alabama, Tuscaloosa, Alabama 35487 (United States); Althammer, M. [Center for Materials for Information Technology, The University of Alabama, Tuscaloosa, Alabama 35487 (United States); Walther-Meissner-Institut, Bayerische Akdademie der Wissenschaften, Garching 85748 (Germany); Rott, K.; Reiss, G. [Thin Films and Physics of Nanostructures, Department of Physics and Center for Spinelectronic Materials and Devices, Bielefeld University, Bielefeld 33615 (Germany)

    2015-09-21

    We investigate the switching characteristics in BaTiO{sub 3}-based ferroelectric tunnel junctions patterned in a capacitive geometry with circular Ru top electrode with diameters ranging from ∼430 to 2300 nm. Two different patterning schemes, viz., lift-off and ion-milling, have been employed to examine the variations in the ferroelectric polarization, switching, and tunnel electro-resistance resulting from differences in the pattering processes. The values of polarization switching field are measured and compared for junctions of different diameter in the samples fabricated using both patterning schemes. We do not find any specific dependence of polarization switching bias on the size of junctions in both sample stacks. The junctions in the ion-milled sample show up to three orders of resistance change by polarization switching and the polarization retention is found to improve with increasing junction diameter. However, similar switching is absent in the lift-off sample, highlighting the effect of patterning scheme on the polarization retention.

  5. Binder Jetting: A Novel Solid Oxide Fuel-Cell Fabrication Process and Evaluation

    Science.gov (United States)

    Manogharan, Guha; Kioko, Meshack; Linkous, Clovis

    2015-03-01

    With an ever-growing concern to find a more efficient and less polluting means of producing electricity, fuel cells have constantly been of great interest. Fuel cells electrochemically convert chemical energy directly into electricity and heat without resorting to combustion/mechanical cycling. This article studies the solid oxide fuel cell (SOFC), which is a high-temperature (100°C to 1000°C) ceramic cell made from all solid-state components and can operate under a wide range of fuel sources such as hydrogen, methanol, gasoline, diesel, and gasified coal. Traditionally, SOFCs are fabricated using processes such as tape casting, calendaring, extrusion, and warm pressing for substrate support, followed by screen printing, slurry coating, spray techniques, vapor deposition, and sputter techniques, which have limited control in substrate microstructure. In this article, the feasibility of engineering the porosity and configuration of an SOFC via an additive manufacturing (AM) method known as binder jet printing was explored. The anode, cathode and oxygen ion-conducting electrolyte layers were fabricated through AM sequentially as a complete fuel cell unit. The cell performance was measured in two modes: (I) as an electrolytic oxygen pump and (II) as a galvanic electricity generator using hydrogen gas as the fuel. An analysis on influence of porosity was performed through SEM studies and permeability testing. An additional study on fuel cell material composition was conducted to verify the effects of binder jetting through SEM-EDS. Electrical discharge of the AM fabricated SOFC and nonlinearity of permeability tests show that, with additional work, the porosity of the cell can be modified for optimal performance at operating flow and temperature conditions.

  6. Preparation of highly hydrophobic cotton fabrics by modification with bifunctional silsesquioxanes in the sol-gel process

    Energy Technology Data Exchange (ETDEWEB)

    Przybylak, Marcin, E-mail: marcin.przybylak@ppnt.poznan.pl [Poznań Science and Technology Park, Adam Mickiewicz University Foundation, Rubież 46, 61-612 Poznań (Poland); Maciejewski, Hieronim, E-mail: maciejm@amu.edu.pl [Poznań Science and Technology Park, Adam Mickiewicz University Foundation, Rubież 46, 61-612 Poznań (Poland); Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614 Poznań (Poland); Dutkiewicz, Agnieszka, E-mail: agdut@interia.pl [Poznań Science and Technology Park, Adam Mickiewicz University Foundation, Rubież 46, 61-612 Poznań (Poland)

    2016-11-30

    Highlights: • Fabric hydrophobization process using bifunctional silsesquioxanes was studied. • Superhydrophobic fabric was produced using fluorofunctional silsesquioxanes. • Surface of modified fabrics was analyzed using different techniques. - Abstract: The surface modification of cotton fabrics was carried out using two types of bifunctional fluorinated silsesquioxanes with different ratios of functional groups. The modification was performed either by one- or two-step process. Two methods, the sol-gel and the dip coating method were used in different configurations. The heat treatment and the washing process were applied after modification. The wettability of cotton fabric was evaluated by measuring water contact angles (WCA). Changes in the surface morphology were examined by scanning electron microscopy (SEM, SEM-LFD) and atomic force microscopy (AFM). Moreover, the modified fabrics were subjected to analysis of elemental composition of the applied coatings using SEM-EDS techniques. Highly hydrophobic textiles were obtained in all cases studied and one of the modifications resulted in imparting superhydrophobic properties. Most of impregnated textiles remained hydrophobic even after multiple washing process which shows that the studied modification is durable.

  7. High-speed organic photo-detectors fabricated by vacuum and solution processes and application for optical transmission

    Science.gov (United States)

    Ohmori, Yutaka; Hamasaki, Tatsunari; Morimune, Taichiro; Kajii, Hirotake

    2008-04-01

    Organic photo-detectors (OPDs) have been discussed as high-speed photo-detectors fabricated by vacuum and solution processes. By vacuum process, OPD was fabricated on an ITO-coated glass substrate by organic molecular beam deposition (OMBD). Copper phthalocyanine (CuPc) and N,N'-bis(2,5-di-tert-butylphenyl) 3,4,9,10-perylene dicarboximide (BPPC) were used as a p-type and an n-type material. The photo response of OPD was evaluated using a laser (λ=650 nm) and clear response signals at 100 MHz were observed. The imaging signals were successfully received using the OPDs. For solution processed OPDs, poly(9,9-dioctylfluorene) and a phosphorescent iridium derivative were used as a host and a dopant material, respectively. A pulsed signal of 100MHz and amore than 40 MHz were observed by the OPDs fabricated by the vacuum processed and the solution processed devices, respectively.

  8. Optimum conditions for fabricating superhydrophobic surface on copper plates via controlled surface oxidation and dehydration processes

    Science.gov (United States)

    Zhang, Yan; Li, Wen; Ma, Fumin; Yu, Zhanlong; Ruan, Min; Ding, Yigang; Deng, Xiangyi

    2013-09-01

    The superhydrophobic surfaces on copper substrate were fabricated by direct oxidation and dehydration processes, and the reaction and modification conditions were optimized. Firstly, the oxidation conditions including the concentrations of K2S2O8 and NaOH, the oxidation time were studied. It is found that the superhydrophobicity would be better if the copper plates were oxidized in 0.06 M K2S2O8 and 3.0 M NaOH solution at 65 °C for 35 min. Then, the modification conditions including modifier concentration and modification time were investigated. The results showed that 5 wt% lauric acid and 1 h modification time were suitable modification conditions for preparing copper-based superhydrophobic surfaces. The surface fabricated under optimized conditions displayed excellent superhydrophobicity of high water contact angle of 161.1° and a low contact angle hysteresis of 2.5°. The surface microstructure and composition of the superhydrophobic surfaces were also characterized by SEM and FT-IR. It is found that the highly concentrated micro/nanostructured sheets and the low surface energy materials on the surface should be responsible for the high superhydrophobicity.

  9. Fabrication of polypyrrole/TiO_2 nanocomposite via electrochemical process and its photoconductivity

    Institute of Scientific and Technical Information of China (English)

    OUYANG Mi; BAI Ru; XU Yi; ZHANG Cheng; MA Chun-an; WANG Mang; CHEN Hong-zheng

    2009-01-01

    Size-controllable and vertically-oriented TiO_2 nanotube (TNT) arrays were fabricated using anodic oxidation method from pure titanium sheets in electrolyte solutions.Then with the TNT arrays as the working electrode,a thin film of polypyrrole (Ppy) was synthesized into the TNT arrays via the electrochemical polymerization.During the process,the appearance of redox peaks in cyclic voltammetry curves of the resulting films indicates the occurrence of polymerization.The morphology,the molecular structure,crystallization and optical properties of the TNT arrays and the resulting polymer were investigated by field-emission scanning electron microscopy (FESEM),X-ray diffractometry (XRD),Fourier transform infrared spectroscopy (FTIR),and UV-vis spectrum analysis,respectively.A dual-layered photoreceptor containing the nanocomposite film as the charge generation layer (CGL) was designed and fabricated.It is found that the photoreceptor based on Ppy/TiO_2 nanotubes as CGL exhibits remarkable photoconductive performance.

  10. Fabrication of solution processed 3D nanostructured CuInGaS₂ thin film solar cells.

    Science.gov (United States)

    Chu, Van Ben; Cho, Jin Woo; Park, Se Jin; Hwang, Yun Jeong; Park, Hoo Keun; Do, Young Rag; Min, Byoung Koun

    2014-03-28

    In this study we demonstrate the fabrication of CuInGaS₂ (CIGS) thin film solar cells with a three-dimensional (3D) nanostructure based on indium tin oxide (ITO) nanorod films and precursor solutions (Cu, In and Ga nitrates in alcohol). To obtain solution processed 3D nanostructured CIGS thin film solar cells, two different precursor solutions were applied to complete gap filling in ITO nanorods and achieve the desirable absorber film thickness. Specifically, a coating of precursor solution without polymer binder material was first applied to fill the gap between ITO nanorods followed by deposition of the second precursor solution in the presence of a binder to generate an absorber film thickness of ∼1.3 μm. A solar cell device with a (Al, Ni)/AZO/i-ZnO/CdS/CIGS/ITO nanorod/glass structure was constructed using the CIGS film, and the highest power conversion efficiency was measured to be ∼6.3% at standard irradiation conditions, which was 22.5% higher than the planar type of CIGS solar cell on ITO substrate fabricated using the same precursor solutions.

  11. Fabrication and evaluation of valsartan–polymer–surfactant composite nanoparticles by using the supercritical antisolvent process

    Directory of Open Access Journals (Sweden)

    Kim MS

    2014-11-01

    Full Text Available Min-Soo Kim,1 In-hwan Baek21College of Pharmacy, Pusan National University, Geumjeong-gu, Busan, Republic of Korea; 2College of Pharmacy, Kyungsung University, Daeyeon-dong, Nam-gu, Busan, Republic of KoreaAbstract: The aim of this study was to fabricate valsartan composite nanoparticles by using the supercritical antisolvent (SAS process, and to evaluate the correlation between in vitro dissolution and in vivo pharmacokinetic parameters for the poorly water-soluble drug valsartan. Spherical composite nanoparticles with a mean size smaller than 400 nm, which contained valsartan, were successfully fabricated by using the SAS process. X-ray diffraction and thermal analyses indicated that valsartan was present in an amorphous form within the composite nanoparticles. The in vitro dissolution and oral bioavailability of valsartan were dramatically enhanced by the composite nanoparticles. Valsartan–hydroxypropyl methylcellulose–poloxamer 407 nanoparticles exhibited faster drug release (up to 90% within 10 minutes under all dissolution conditions and higher oral bioavailability than the raw material, with an approximately 7.2-fold higher maximum plasma concentration. In addition, there was a positive linear correlation between the pharmacokinetic parameters and the in vitro dissolution efficiency. Therefore, the preparation of composite nanoparticles with valsartan–hydroxypropyl methylcellulose and poloxamer 407 by using the SAS process could be an effective formulation strategy for the development of a new dosage form of valsartan with high oral bioavailability.Keywords: supersaturation, bioavailability, solid dispersion, dissolution, supercritical fluid

  12. A wafer level vacuum encapsulated capacitive accelerometer fabricated in an unmodified commercial MEMS process.

    Science.gov (United States)

    Merdassi, Adel; Yang, Peng; Chodavarapu, Vamsy P

    2015-03-25

    We present the design and fabrication of a single axis low noise accelerometer in an unmodified commercial MicroElectroMechanical Systems (MEMS) process. The new microfabrication process, MEMS Integrated Design for Inertial Sensors (MIDIS), introduced by Teledyne DALSA Inc. allows wafer level vacuum encapsulation at 10 milliTorr which provides a high Quality factor and reduces noise interference on the MEMS sensor devices. The MIDIS process is based on high aspect ratio bulk micromachining of single-crystal silicon layer that is vacuum encapsulated between two other silicon handle wafers. The process includes sealed Through Silicon Vias (TSVs) for compact design and flip-chip integration with signal processing circuits. The proposed accelerometer design is sensitive to single-axis in-plane acceleration and uses a differential capacitance measurement. Over ±1 g measurement range, the measured sensitivity was 1 fF/g. The accelerometer system was designed to provide a detection resolution of 33 milli-g over the operational range of ±100 g.

  13. A Wafer Level Vacuum Encapsulated Capacitive Accelerometer Fabricated in an Unmodified Commercial MEMS Process

    Directory of Open Access Journals (Sweden)

    Adel Merdassi

    2015-03-01

    Full Text Available We present the design and fabrication of a single axis low noise accelerometer in an unmodified commercial MicroElectroMechanical Systems (MEMS process. The new microfabrication process, MEMS Integrated Design for Inertial Sensors (MIDIS, introduced by Teledyne DALSA Inc. allows wafer level vacuum encapsulation at 10 milliTorr which provides a high Quality factor and reduces noise interference on the MEMS sensor devices. The MIDIS process is based on high aspect ratio bulk micromachining of single-crystal silicon layer that is vacuum encapsulated between two other silicon handle wafers. The process includes sealed Through Silicon Vias (TSVs for compact design and flip-chip integration with signal processing circuits. The proposed accelerometer design is sensitive to single-axis in-plane acceleration and uses a differential capacitance measurement. Over ±1 g measurement range, the measured sensitivity was 1fF/g. The accelerometer system was designed to provide a detection resolution of 33 milli-g over the operational range of ±100 g.

  14. Design and fabrication of a glovebox for the Plasma Hearth Process radioactive bench-scale system

    Energy Technology Data Exchange (ETDEWEB)

    Wahlquist, D.R. [Argonne National Lab., Idaho Falls, ID (United States). Technology Development Div.

    1996-07-01

    This paper presents some of the design considerations and fabrication techniques for building a glovebox for the Plasma Hearth Process (PHP) radioactive bench-scale system. The PHP radioactive bench-scale system uses a plasma torch to process a variety of radioactive materials into a final vitrified waste form. The processed waste will contain plutonium and trace amounts of other radioactive materials. The glovebox used in this system is located directly below the plasma chamber and is called the Hearth Handling Enclosure (HHE). The HHE is designed to maintain a confinement boundary between the processed waste and the operator. Operations that take place inside the HHE include raising and lowering the hearth using a hydraulic lift table, transporting the hearth within the HHE using an overhead monorail and hoist system, sampling and disassembly of the processed waste and hearth, weighing the hearth, rebuilding a hearth, and sampling HEPA filters. The PHP radioactive bench-scale system is located at the TREAT facility at Argonne National Laboratory-West in Idaho Falls, Idaho.

  15. Innovative layer-by-layer processing for flame retardant behavior of cotton fabric

    Science.gov (United States)

    Flame retardant behavior has been prepared by the layer-by layer assemblies of kaolin/casein with inorganic chemicals on cotton fabrics. Three different kinds of cotton fabrics (print cloth, mercerized print cloth, and mercerized twill fabric) were prepared with solutions of mixture of BPEI, urea, ...

  16. Vertical triple-junction RGB optical sensor with signal processing based on the determination of the space-charge region borders.

    Science.gov (United States)

    Tadić, Nikša; Schidl, Stefan; Zimmermann, Horst

    2014-09-01

    A triple-junction RGB optical sensor with vertically stacked photodiodes and signal processing that provides precise values of the currents generated by blue, green, and red light is presented. The signal processing is based on the determination of the border depths of the space-charge regions of all three photodiodes. A current-mode implementation using current conveyors and variable-gain current amplifiers is introduced. The responsivities of all three photodiodes calculated using the proposed approach are in very good agreement with the measured results.

  17. CMOS compatible fabrication process of MEMS resonator for timing reference and sensing application

    Science.gov (United States)

    Huynh, Duc H.; Nguyen, Phuong D.; Nguyen, Thanh C.; Skafidas, Stan; Evans, Robin

    2015-12-01

    Frequency reference and timing control devices are ubiquitous in electronic applications. There is at least one resonator required for each of this device. Currently electromechanical resonators such as crystal resonator, ceramic resonator are the ultimate choices. This tendency will probably keep going for many more years. However, current market demands for small size, low power consumption, cheap and reliable products, has divulged many limitations of this type of resonators. They cannot be integrated into standard CMOS (Complement metaloxide- semiconductor) IC (Integrated Circuit) due to material and fabrication process incompatibility. Currently, these devices are off-chip and they require external circuitries to interface with the ICs. This configuration significantly increases the overall size and cost of the entire electronic system. In addition, extra external connection, especially at high frequency, will potentially create negative impacts on the performance of the entire system due to signal degradation and parasitic effects. Furthermore, due to off-chip packaging nature, these devices are quite expensive, particularly for high frequency and high quality factor devices. To address these issues, researchers have been intensively studying on an alternative for type of resonator by utilizing the new emerging MEMS (Micro-electro-mechanical systems) technology. Recent progress in this field has demonstrated a MEMS resonator with resonant frequency of 2.97 GHz and quality factor (measured in vacuum) of 42900. Despite this great achievement, this prototype is still far from being fully integrated into CMOS system due to incompatibility in fabrication process and its high series motional impedance. On the other hand, fully integrated MEMS resonator had been demonstrated but at lower frequency and quality factor. We propose a design and fabrication process for a low cost, high frequency and a high quality MEMS resonator, which can be integrated into a standard

  18. Resonant behavior of the barrier of YBa{sub 2}Cu{sub 3}O{sub 7} grain boundary Josephson junctions fabricated on bicrystalline substrates with different geometries

    Energy Technology Data Exchange (ETDEWEB)

    Navacerrada, M.A., E-mail: mdelosangeles.navacerrada@upm.es [Grupo de Acustica Arquitectonica, Escuela Tecnica Superior de Arquitectura, Universidad Politecnica de Madrid, Avenida Juan de Herrera 4, 28040 Madrid (Spain); Lucia, M.L.; Sanchez-Quesada, F. [Departamento Fisica Aplicada III (Electricidad y Electronica), Facultad de Cc. Fisicas, Universidad Complutense, Avenida Complutense s/n, 28040 Madrid (Spain)

    2012-12-14

    We have analyzed a resonant behavior in the dielectric constant associated to the barrier of YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO) grain boundary Josephson junctions (GBJJs) fabricated on a wide variety of bicrystalline substrates: 12 Degree-Sign [0 0 1] tilt asymmetric, 24 Degree-Sign [0 0 1] tilt asymmetric, 24 Degree-Sign [0 0 1] tilt symmetric, 24 Degree-Sign [1 0 0] tilt asymmetric, 45 Degree-Sign [1 0 0] tilt asymmetric and 24 Degree-Sign [0 0 1] tilt symmetric +45 Degree-Sign [1 0 0] tilt asymmetric bicrystals. The resonance analysis allows us to estimate a more appropriate value of the relative dielectric constant, and so a more adequate value for the length L of the normal N region assuming a SNINS model for the barrier. In this work, the L dependence on the critical current density Jc has been investigated. This analysis makes possible a single representation for all the substrate geometries independently on around which axes the rotation is produced to generate the grain boundary. On the other hand, no clear evidences exist on the origin of the resonance. The resonance frequency is in the order of 10{sup 11} Hz, pointing to a phonon dynamic influence on the resonance mechanism. Besides, its position is affected by the oxygen content of the barrier: a shift at low frequencies is observed when the misorientation angle increases.

  19. Fabrication of a TiO2-P25/(TiO2-P25+TiO2 nanotubes) junction for dye sensitized solar cells

    Institute of Scientific and Technical Information of China (English)

    Nguyen Huy Hao; Gobinda Gyawali; Tohru Sekino; Soo Wohn Lee

    2016-01-01

    The dye sensitized solar cell (DSSC), which converts solar light into electric energy, is expected to be a promising renewable energy source for today's world. In this work, dye sensitized solar cells, one con-taining a single layer and one containing a double layer, were fabricated. In the double layer DSSC structure, the under-layer was TiO2-P25 film, and the top layer consisted of a mixture of TiO2-P25 and TiO2 nanotubes. The results indicated that the efficiency of the DSSC with the double layer structure was a significant improvement in comparison to the DSSC consisting of only a single film layer. The addition of TiO2-P25 in the top layer caused an improvement in the adsorption of dye molecules on the film rather than on the TiO2 nanotubes only. The presence of the TiO2 nanotubes together with TiO2-P25 in the top layer revealed the enhancement in harvesting the incident light and an improvement of electron transport through the film.

  20. Fabrication of a TiO2-P25/(TiO2-P25+TiO2 nanotubes junction for dye sensitized solar cells

    Directory of Open Access Journals (Sweden)

    Nguyen Huy Hao

    2016-08-01

    Full Text Available The dye sensitized solar cell (DSSC, which converts solar light into electric energy, is expected to be a promising renewable energy source for today's world. In this work, dye sensitized solar cells, one containing a single layer and one containing a double layer, were fabricated. In the double layer DSSC structure, the under-layer was TiO2-P25 film, and the top layer consisted of a mixture of TiO2-P25 and TiO2 nanotubes. The results indicated that the efficiency of the DSSC with the double layer structure was a significant improvement in comparison to the DSSC consisting of only a single film layer. The addition of TiO2-P25 in the top layer caused an improvement in the adsorption of dye molecules on the film rather than on the TiO2 nanotubes only. The presence of the TiO2 nanotubes together with TiO2-P25 in the top layer revealed the enhancement in harvesting the incident light and an improvement of electron transport through the film.

  1. Efficient composite fabrication using electron-beam rapidly cured polymers engineered for several manufacturing processes

    Energy Technology Data Exchange (ETDEWEB)

    Walton, T.C. [Aeroplas Corp. International, Nashua, NH (United States); Crivello, J.V. [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Chemistry

    1995-10-01

    Low cost, efficiently processed ultra high specific strength and stiffness graphite fiber reinforced polymeric composite materials are of great interest to commercial transportation, construction and aerospace industries for use in various components with enhanced degrees of weight reduction, corrosion/erosion resistance and fatigue resistance. 10 MeV Electron Beam cure processing has been found to increase the cure rate by an order of magnitude over thermally cured systems yet provide less molded in stresses and high T{sub g}s. However, a limited range of resins are available which are easily processed with low shrinkage and with performance properties equal or exceeding those of state of the art toughened epoxies and BMI`s. The technology, introduced by an academia-industry partnership sparked by Langley Research Center utilizes a cost effective, rapid curing polymeric composite processing technique which effectively reduces the need for expensive tooling and energy inefficient autoclave processing and can cure the laminate in seconds (compared to hours for thermal curing) in ambient or sub-ambient conditions. The process is based on electron beam (E-Beam) curing of a new series of (65 to 1,000,000 cPs.) specially formulated resins that have been shown to exhibit excellent mechanical and physical properties once cured. Fabrication processes utilizing these specially formulated and newly commercialized resins, (e.g. including Vacuum Assist Resin Transfer molding (VARTM), vacuum bag prepreg layup, pultrusion and filament winding grades) are engineered to cure with low shrinkage, provide excellent mechanical properties, be processed solventless (environmentally friendly) and are inherently non toxic.

  2. Fabrication of hierarchical -Co(OH)2 microspheres via hydrothermal process

    Indian Academy of Sciences (India)

    Guang Sheng Cao; Xiao Juan Zhang; Ling Su

    2011-07-01

    Hierarchical -Co(OH)2 microspheres with 20–50 m diameter assembled from nanoplate building blocks were successfully fabricated via a hydrothermal process in the presence of a cation surfactant cetyltrimethylammonium bromide (CTAB). The products are characterized in detail by multiform techniques: X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis. The effect of CTAB and pH value on the -Co(OH)2 morphology was also investigated. When pH value is maintained at 9, an appropriate added amount of CTAB (3 g) is the crucial prerequisite for the formation of this interesting morphology. In this experiment, pH value of the solution and the cation surfactant CTAB together results in the formation of hierarchical -Co(OH)2 microsphere structures assembled from nanoplates.

  3. Nonlinear enhancement in photonic crystal slow light waveguides fabricated using CMOS-compatible process.

    Science.gov (United States)

    Shinkawa, Mizuki; Ishikura, Norihiro; Hama, Yosuke; Suzuki, Keijiro; Baba, Toshihiko

    2011-10-24

    We have studied low-dispersion slow light and its nonlinear enhancement in photonic crystal waveguides. In this work, we fabricated the waveguides using Si CMOS-compatible process. It enables us to integrate spotsize converters, which greatly simplifies the optical coupling from fibers as well as demonstration of the nonlinear enhancement. Two-photon absorption, self-phase modulation and four-wave mixing were observed clearly for picosecond pulses in a 200-μm-long device. In comparison with Si wire waveguides, a 60-120 fold higher nonlinearity was evaluated for a group index of 51. Unique intensity response also occurred due to the specific transmission spectrum and enhanced nonlinearities. Such slow light may add various functionalities in Si photonics, while loss reduction is desired for ensuring the advantage of slow light.

  4. Fabrication and Characterisation of Silicon Waveguides for High-Speed Optical Signal Processing

    DEFF Research Database (Denmark)

    Jensen, Asger Sellerup

    This Ph.D. thesis treats various aspects of silicon photonics. From the limitations of silicon as a linear and nonlinear waveguide medium to its synergy with other waveguide materials. Various methods for reducing sidewall roughness and line edge roughness of silicon waveguides are attempted....... The methods include enhancements of etch mask roughness as well as etch isotropy and direct reduction of already present sidewall roughness. Although promising roughness assessments were made based on electron microscopy images it did not translate into significantly lower propagation loss in fabricated...... signal processing could be demonstrated. This includes four wave mixing based wavelength conversion of a 320Gb/s Nyquist OTDM signal and cross phase modulation based signal regeneration of a 40Gb/s OTDM signal. Finally, a new type of low loss electrically driven optical modulator in silicon and silicon...

  5. Electric properties of La-modified lead titanate thin films fabricated by sol-gel processing

    Energy Technology Data Exchange (ETDEWEB)

    Hyun, June Won; Kim, Gang Bae [Dankook Univ., Chonan (Korea, Republic of)

    2003-01-01

    Ferroelectric lead lanthanum titanate (PLT) thin films were fabricated by sol-gel processing and spin-coating on Pt substrates. The electric properties and the microstructure were studied by changing the La content from 18 to 28 mol%. The X-ray diffraction patterns showed that the PLT films sintered at 650 .deg. C for 30 min were crystallized with a stable perovskite structure. The dielectric constant of PLT films increased with addition of La content up to 21 mol%, and then decreased with La content up to 28 mol% at room temperature. The remanent polarization, coercive field, and leakage current density of the PLT thin films decreased with increasing La content. The fatigue property did not change significantly as the number of switching cycles was increased.

  6. Facile fabrication processes for hydrogel-based microfluidic devices made of natural biopolymers

    Science.gov (United States)

    Yajima, Yuya; Yamada, Masumi; Yamada, Emi; Iwase, Masaki; Seki, Minoru

    2014-01-01

    We present facile strategies for the fabrication of two types of microfluidic devices made of hydrogels using the natural biopolymers, alginate, and gelatin as substrates. The processes presented include the molding-based preparation of hydrogel plates and their chemical bonding. To prepare calcium-alginate hydrogel microdevices, we suppressed the volume shrinkage of the alginate solution during gelation using propylene glycol alginate in the precursor solution along with sodium alginate. In addition, a chemical bonding method was developed using a polyelectrolyte membrane of poly-L-lysine as the electrostatic glue. To prepare gelatin-based microdevices, we used microbial transglutaminase to bond hydrogel plates chemically and to cross-link and stabilize the hydrogel matrix. As an application, mammalian cells (fibroblasts and vascular endothelial cells) were cultivated on the microchannel surface to form three-dimensional capillary-embedding tissue models for biological research and tissue engineering. PMID:24803964

  7. Fabrication of Nanosized Lanthanum Zirconate Powder and Deposition of Thermal Barrier Coating by Plasma Spray Process

    Science.gov (United States)

    Mishra, S. K.; Jagdeesh, N.; Pathak, L. C.

    2016-07-01

    The present manuscript discusses our findings on fabrication of nanosized lanthanum zirconate powder for thermal barrier coating application and its coating by plasma spray on nickel-based superalloy substrate. Single-phase La2Zr2O7 coating of thickness of the order of 45 µm on the Ni-Cr-Al bond coat coated Ni-based superalloy substrate was deposited by plasma spray process. The layers at the interface did not show spallation and inter diffusion was very less. The microstructure, interface, porosity, and mechanical properties of different layers are investigated. The lanthanum zirconate hardness and modulus were 10.5 and 277 GPa, respectively. The load depth curve for lanthanum zirconate showed good elastic recovery around 74%.

  8. Laser stereolithography and supercritical fluid processing for custom-designed implant fabrication.

    Science.gov (United States)

    Popov, V K; Evseev, A V; Ivanov, A L; Roginski, V V; Volozhin, A I; Howdle, S M

    2004-02-01

    This paper describes the laser photopolymerization of a liquid mixture of polyfunctional acrylic monomers, photoinitiator and hydroxyapatite (HA). Pure polymeric and composite materials of specific shape and structure were fabricated by laser stereolithography based on images derived from three-dimensional (3D) computer modeling. The polymeric objects then were treated with supercritical carbon dioxide to remove potentially toxic residues (monomers, low molecular weight oligomers, etc.) and to provide interconnective microporosity. Finally, samples were implanted into white rats (diastolic epiphysis of femoral bone) to study living tissue response and processes of osteointegration and osteoinduction. It was shown that incorporation of HA into the composite implant structure encouraged periosteal as well as endosteal osteogenesis and improved their osteointegrative characteristics in particular. Supercritical carbon dioxide treatment significantly enhanced the biocompatibility of the materials, increasing the area of direct contact of the implant surface with regenerated bone tissue.

  9. Alternative Post-Processing on a CMOS Chip to Fabricate a Planar Microelectrode Array

    Science.gov (United States)

    López-Huerta, Francisco; Herrera-May, Agustín L.; Estrada-López, Johan J.; Zuñiga-Islas, Carlos; Cervantes-Sanchez, Blanca; Soto, Enrique; Soto-Cruz, Blanca S.

    2011-01-01

    We present an alternative post-processing on a CMOS chip to release a planar microelectrode array (pMEA) integrated with its signal readout circuit, which can be used for monitoring the neuronal activity of vestibular ganglion neurons in newborn Wistar strain rats. This chip is fabricated through a 0.6 μm CMOS standard process and it has 12 pMEA through a 4 × 3 electrodes matrix. The alternative CMOS post-process includes the development of masks to protect the readout circuit and the power supply pads. A wet etching process eliminates the aluminum located on the surface of the p+-type silicon. This silicon is used as transducer for recording the neuronal activity and as interface between the readout circuit and neurons. The readout circuit is composed of an amplifier and tunable bandpass filter, which is placed on a 0.015 mm2 silicon area. The tunable bandpass filter has a bandwidth of 98 kHz and a common mode rejection ratio (CMRR) of 87 dB. These characteristics of the readout circuit are appropriate for neuronal recording applications. PMID:22346681

  10. Alternative post-processing on a CMOS chip to fabricate a planar microelectrode array.

    Science.gov (United States)

    López-Huerta, Francisco; Herrera-May, Agustín L; Estrada-López, Johan J; Zuñiga-Islas, Carlos; Cervantes-Sanchez, Blanca; Soto, Enrique; Soto-Cruz, Blanca S

    2011-01-01

    We present an alternative post-processing on a CMOS chip to release a planar microelectrode array (pMEA) integrated with its signal readout circuit, which can be used for monitoring the neuronal activity of vestibular ganglion neurons in newborn Wistar strain rats. This chip is fabricated through a 0.6 μm CMOS standard process and it has 12 pMEA through a 4 × 3 electrodes matrix. The alternative CMOS post-process includes the development of masks to protect the readout circuit and the power supply pads. A wet etching process eliminates the aluminum located on the surface of the p+ -type silicon. This silicon is used as transducer for recording the neuronal activity and as interface between the readout circuit and neurons. The readout circuit is composed of an amplifier and tunable bandpass filter, which is placed on a 0.015 mm2 silicon area. The tunable bandpass filter has a bandwidth of 98 kHz and a common mode rejection ratio (CMRR) of 87 dB. These characteristics of the readout circuit are appropriate for neuronal recording applications.

  11. Effect of fabrication and processing technology on the biodegradability of magnesium nanocomposites.

    Science.gov (United States)

    Ma, Chao; Chen, Lianyi; Xu, Jiaquan; Fehrenbacher, Axel; Li, Yan; Pfefferkorn, Frank E; Duffie, Neil A; Zheng, Jing; Li, Xiaochun

    2013-07-01

    Magnesium and its alloys have gained significant attention recently as potential alternatives for biodegradable materials due to their unique biodegradability, biocompatibility, and mechanical properties. However, magnesium alloys tend to have high corrosion rates in biological liquids, thus presenting a potential problem if a magnesium implant/device needs to maintain mechanical integrity for a sufficient period under practical physiological conditions. In this study, hydroxyapatite nanoparticles were used to form magnesium based metal matrix nanocomposites (MMNC) through two processes: friction stir processing (FSP) and a two-state nanoprocessing (TSnP) combining liquid state ultrasonic processing and solid state FSP. In addition, laser surface melting (LSM) was carried out for further surface treatment. In vitro immersion tests indicated that the corrosion rate of MMNC decreased by 52% compared with pure Mg through FSP. Potentiodynamic polarization tests showed that the corrosion current of MMNC decreased by 71% and 30%, respectively, by TSnP and LSM when compared with pure Mg or untreated counterparts. This study suggests that fabrication of MMNC and further processing through FSP and LSM can robustly enhance the corrosion resistance of magnesium, which will boost its potential for biological applications.

  12. Study on properties of CFRP fabricated by VA-RTM process

    Science.gov (United States)

    Jeoung, Sun Kyoung; Hwang, Ye Jin; Lee, Hyun Wook; Son, Soon Keun; Kim, Hyung Sik; Ha, Jin Uk

    2016-03-01

    Carbon fiber reinforced plastics (CFRP) have a lot of attention from industry and academia due to its excellent mechanical property. It has been used for aircraft, automotive and so on, since it can replace metallic materials and reduce total weight with increased physical properties. However, the manufacturing process and the material cost are still challenging to be commercialized in the automotive market. Therefore, many researchers are trying to minimize materials and process cost for broadening their applications. In this study, thermoset epoxy resins were used for binder of CFRP. Epoxy resins were investigated in order to figure out optimized curing speed under vacuum assisted resin transfer molding (VARTM) processing condition. Mechanical properties of CFRP with different carbon fiber orientation and woven carbon fiber were compared to mathematically simulated results. In order to develop the application of automobile component, reliability tests of CFRP were carried out. Tensile strength of CFRP is increased when the orientation angle between fiber and axis of load was decreased (90°→ 0°). It is considered that epoxy and carbon fiber absorbed the tensile energy because the orientation of fiber and the load bearing are matched with axis direction. In addition, the CFRP automobile engine hood was fabricated by VARTM process. Drop weight impact tests (20kg & 100kg weight) were carried out in order to simulate crash performance of CFRP engine hoods.

  13. Fabrication of Dish-Shaped Micro Parts by Laser Indirect Shocking Compound Process

    Directory of Open Access Journals (Sweden)

    Huixia Liu

    2016-06-01

    Full Text Available Compound process technology has been investigated for many years on a macro scale, but only a few studies can be found on a micro scale due to the difficulties in tool manufacturing, parts transporting and punch-die alignment. In this paper, a novel technology of combining the laser shock wave and soft punch was introduced to fabricate the dish-shaped micro-parts on copper to solve these difficulties. This compound process includes deep drawing, punching and blanking and these processes can be completed almost at the same time because the duration time of laser is quite short, so the precision of the micro-parts can be ensured. A reasonable laser energy of 1550 mJ made the morphology, depth of deformation, dimensional accuracy and surface roughness achieve their best results when the thickness of the soft punches was 200 μm. In addition, thicker soft punches may hinder the compound process due to the action of unloading waves based on the elastic wave theory. So, the greatest thickness of the soft punches was 200 μm.

  14. Fabrication of protein microarrays for alpha fetoprotein detection by using a rapid photo-immobilization process

    Directory of Open Access Journals (Sweden)

    Sirasa Yodmongkol

    2016-03-01

    Full Text Available In this study, protein microarrays based on sandwich immunoassays are generated to quantify the amount of alpha fetoprotein (AFP in blood serum. For chip generation a mixture of capture antibody and a photoactive copolymer consisting of N,N-dimethylacrylamide (DMAA, methacryloyloxy benzophenone (MaBP, and Na-4-styrenesulfonate (SSNa was spotted onto unmodified polymethyl methacrylate (PMMA substrates. Subsequently to printing of the microarray, the polymer and protein were photochemically cross-linked and the forming, biofunctionalized hydrogels simultaneously bound to the chip surface by short UV- irradiation. The obtained biochip was incubated with AFP antigen, followed by biotinylated AFP antibody and streptavidin-Cy5 and the fluorescence signal read-out. The developed microarray biochip covers the range of AFP in serum samples such as maternal serum in the range of 5 and 100 ng/ml. The chip production process is based on a fast and simple immobilization process, which can be applied to conventional plastic surfaces. Therefore, this protein microarray production process is a promising method to fabricate biochips for AFP screening processes.

  15. Fabrication of Surface Level Cu/SiCp Nanocomposites by Friction Stir Processing Route

    Directory of Open Access Journals (Sweden)

    Cartigueyen Srinivasan

    2015-01-01

    Full Text Available Friction stir processing (FSP technique has been successfully employed as low energy consumption route to prepare copper based surface level nanocomposites reinforced with nanosized silicon carbide particles (SiCp. The effect of FSP parameters such as tool rotational speed, processing speed, and tool tilt angle on microstructure and microhardness was investigated. Single pass FSP was performed based on Box-Behnken design at three factors in three levels. A cluster of blind holes 2 mm in diameter and 3 mm in depth was used as particulate deposition technique in order to reduce the agglomeration problem during composite fabrication. K-type thermocouples were used to measure temperature histories during FSP. The results suggest that the heat generation during FSP plays a significant role in deciding the microstructure and microhardness of the surface composites. Microstructural observations revealed a uniform dispersion of nanosized SiCp without any agglomeration problem and well bonded with copper matrix at different process parameter combinations. X-ray diffraction study shows that no intermetallic compound was produced after processing. The microhardness of nanocomposites was remarkably enhanced and about 95% more than that of copper matrix.

  16. Cellulose based cationic adsorbent fabricated via radiation grafting process for treatment of dyes waste water.

    Science.gov (United States)

    Goel, Narender Kumar; Kumar, Virendra; Misra, Nilanjal; Varshney, Lalit

    2015-11-05

    A cationized adsorbent was prepared from cellulosic cotton fabric waste via a single step-green-radiation grafting process using gamma radiation source, wherein poly[2-(methacryloyloxy) ethyl]trimethylammonium chloride (PMAETC) was covalently attached to cotton cellulose substrate. Radiation grafted (PMAETC-g-cellulose) adsorbent was investigated for removal of acid dyes from aqueous solutions using two model dyes: Acid Blue 25 (AB25) and Acid Blue 74 (AB74). The equilibrium adsorption data was analyzed by Langmuir and Freundlich isotherms, whereas kinetic data was analyzed by pseudo first order, pseudo second order, intra particle diffusion and Boyd's models. The PMAETC-g-cellulose adsorbent with 25% grafting yield exhibited equilibrium adsorption capacities of ∼ 540.0mg/g and ∼ 340.0mg/g for AB25 and AB74, respectively. Linear and nonlinear fitting of adsorption data suggested that the equilibrium adsorption process followed Langmuir adsorption isotherm model, whereas, the kinetic adsorption process followed pseudo-second order model. The multi-linearities observed in the intra-particle kinetic plots suggested that the intraparticle diffusion was not the only rate-controlling process in the adsorption of acid dyes on the adsorbent, which was further supported by Boyd's model. The adsorbent could be regenerated by eluting the adsorbed dye from the adsorbent and could be repeatedly used.

  17. Design of thin InGaAsN(Sb) n-i-p junctions for use in four-junction concentrating photovoltaic devices

    Science.gov (United States)

    Wilkins, Matthew M.; Gupta, James; Jaouad, Abdelatif; Bouzazi, Boussairi; Fafard, Simon; Boucherif, Abderraouf; Valdivia, Christopher E.; Arès, Richard; Aimez, Vincent; Schriemer, Henry P.; Hinzer, Karin

    2017-04-01

    Four-junction solar cells for space and terrestrial applications require a junction with a band gap of ˜1 eV for optimal performance. InGaAsN or InGaAsN(Sb) dilute nitride junctions have been demonstrated for this purpose, but in achieving the 14 mA/cm2 short-circuit current needed to match typical GaInP and GaAs junctions, the open-circuit voltage (VOC) and fill factor of these junctions are compromised. In multijunction devices incorporating materials with short diffusion lengths, we study the use of thin junctions to minimize sensitivity to varying material quality and ensure adequate transmission into lower junctions. An n-i-p device with 0.65-μm absorber thickness has sufficient short-circuit current, however, it relies less heavily on field-aided collection than a device with a 1-μm absorber. Our standard cell fabrication process, which includes a rapid thermal anneal of the contacts, yields a significant improvement in diffusion length and device performance. By optimizing a four-junction cell around a smaller 1-sun short-circuit current of 12.5 mA/cm2, we produced an InGaAsN(Sb) junction with open-circuit voltage of 0.44 V at 1000 suns (1 sun=100 mW/cm2), diode ideality factor of 1.4, and sufficient light transmission to allow >12.5 mA/cm2 in all four subcells.

  18. Design and fabrication of a 30 T superconducting solenoid using overpressure processed Bi2212 round wire

    Energy Technology Data Exchange (ETDEWEB)

    Flanagan, Gene [Muons, Inc., Batavia, IL (United States); Johnson, Rolland [Muons, Inc., Batavia, IL (United States)

    2016-02-18

    High field superconducting magnets are used in particle colliders, fusion energy devices, and spectrometers for medical imaging and advanced materials research. Magnets capable of generating fields of 20-30 T are needed by future accelerator facilities. A 20-30 T magnet will require the use of high-temperature superconductors (HTS) and therefore the challenges of high field HTS magnet development need to be addressed. Superconducting Bi2Sr2CaCu2Ox (Bi2212) conductors fabricated by the oxide-powder-in-tube (OPIT) technique have demonstrated the capability to carry large critical current density of 105 A/cm2 at 4.2 K and in magnetic fields up to 45 T. Available in round wire multi-filamentary form, Bi2212 may allow fabrication of 20-50 T superconducting magnets. Until recently the performance of Bi2212 has been limited by challenges in realizing high current densities (Jc ) in long lengths. This problem now is solved by the National High Magnetic Field Lab using an overpressure (OP) processing technique, which uses external pressure to process the conductor. OP processing also helps remove the ceramic leakage that results when Bi-2212 liquid leaks out from the sheath material and reacts with insulation, coil forms, and flanges. Significant advances have also been achieved in developing novel insulation materials (TiO2 coating) and Ag-Al sheath materials that have higher mechanical strengths than Ag-0.2wt.% Mg, developing heat treatment approaches to broadening the maximum process temperature window, and developing high-strength, mechanical reinforced Bi-2212 cables. In the Phase I work, we leveraged these new opportunities to prototype overpressure processed solenoids and test them in background fields of up to 14 T. Additionally a design of a fully superconducting 30 T solenoid was produced. This work in conjunction with the future path outlined in the Phase II proposal would

  19. Measuring Structural Parameters of Knitted Fabrics by Digital Image Processing Techniques

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    In the knitting industry the measurements of the stitchdensity and the stitch length are usually done manually,which may lead to lower efficiency and less definition and also bring subjective ideas into the test results. In order to improve the effect we can measure with Digital Image Processing Techniques. A piece of sample is scanned into computer and changed into a digital image, which is processed with media filtering. To acquire the powerspectrum, the image in the spatial domain is converted into the frequency domain. Picking up the characteristic points describing the stitch density and the stitch length separately in the power spectra and reconstructing them, the values of the stitch density and the stitch length could be calculated.When measuring the stitch length, we should establish a geometric model of the stitch based on the digital image processing, which provides a method to transform the stitch length in the two-dimension space into the three-dimension space and to measure the value of the stitch length more accurately. This method also provides a new way to measure the stitch length without damaging the fabric.

  20. High-aspect-ratio photoresist processing for fabrication of high resolution and thick micro-windings

    Science.gov (United States)

    Anthony, Ricky; Laforge, Elias; Casey, Declan P.; Rohan, James F.; O'Mathuna, Cian

    2016-10-01

    DC winding losses remain a major roadblock in realizing high efficiency micro-magnetic components (inductors/transformers). This paper reports an optimized photoresist process using negative tone and acrylic based THB-151N (from JSR Micro), to achieve one of the highest aspect ratio (17:1) and resolution (~5 µm) resist patterns for fabrication of thick (~80 µm) micro-winding using UV lithography. The process was optimized to achieve photoresist widths from 5 µm to 20 µm with resist thickness of ~85 µm in a single spin step. Unlike SU-8, this resist can be readily removed and shows a near-vertical (~91°) electroplated Cu side-wall profile. Moreover, the high resolution compared to available resist processes enables a further reduction in the footprint area and can potentially increase the number of winding thereby increasing the inductance density for micro-magnetic components. Resistance measurements of electroplated copper winding of air-core micro-inductors within the standard 0402 size (0.45 mm2 footprint area) suggested a 42% decrease in resistance (273 mΩ-159 mΩ) with the increase in electroplated Cu thickness (from 50 µm to 80 µm). Reduction of the spacings (from 10 µm to 5 µm) enabled further miniaturisation of the device footprint area (from 0.60 mm2 to 0.45 mm2) without significant increase in resistance.

  1. Ergonomic Design Measures on Work Process and Workplace Layout in the Selected Structural and Fabrication Shops

    Directory of Open Access Journals (Sweden)

    Suzette M. Mercado

    2015-11-01

    Full Text Available The study aimed to analyze the process and workplace layout in the selected structural and fabrication shops located in Batangas, Philippines thus provide improvements using the results of Ergonomic Design Measures. These shops generally focused on preparation, cutting, welding, grinding and assembly using multi-functioning machines and many aspects of human work. Using different Ergonomic Assessment Checklist, Rapid Entire Body Assessment (REBA, Rapid Upper Limb Assessment (RULA and Ovako Working Posture Assessment System (OWAS, and with direct observations, it was found out that existing design of the work processes and workplace layout does not match the ergonomic requirements. The study exposed the presence of Musculoskeletal Disorder (MSD risks due to awkward posture, forceful exertion and fatigue; position of workers is dangerous to themselves due to inappropriate measurement of facilities which is in need of change. The researcher recommended ergonomically based actions to address the health, comfort, and well-being of employees such as changing the workstation surface height, integration of safeguarding; application of Group Technology to reduce the production lead time and material handling and offered smooth workflow in production line. Furthermore, the researcher developed a proposed workstation and workplace design as part of the ergonomic-based actions. The effectiveness of the proposed design alternatives were measured with the use of Trade-off Analysis technique, such as, Standard Weighted Sum Method, MAXIMIN decision and Analytic Hierarchy Process.

  2. Melt-processed poly(vinyl alcohol) composites filled with microcrystalline cellulose from waste cotton fabrics.

    Science.gov (United States)

    Sun, Xunwen; Lu, Canhui; Liu, Yong; Zhang, Wei; Zhang, Xinxing

    2014-01-30

    Waste cotton fabrics (WCFs), which are generated in a large volume from the textile industry, have caused serious disposal problem. Recycling WCFs into value-added products is one of the vital measures for both environmental and economic benefits. In this study, microcrystalline cellulose (MCC) was prepared by acid hydrolysis of WCFs, and used as reinforcement for melt-processed poly(vinyl alcohol) (PVA) with water and formamide as plasticizer. The microstructure and mechanical properties of the melt-processed PVA/MCC composites were characterized by Fourier transform infrared spectra, Raman spectra, differential scanning calorimetry, thermal gravimetric analysis, X-ray diffraction, tensile tests and dynamic mechanical analysis. The results indicated that MCC could establish strong interfacial interaction with PVA through hydrogen bonding. As a result, the crystallization of PVA was confined and its melting temperature was decreased, which was beneficial for the melt-processing of PVA. Compared with the unfilled PVA, the PVA/MCC composites exhibited remarkable improvement in modulus and tensile strength.

  3. Silicon carbide high performance optics: a cost-effective, flexible fabrication process

    Science.gov (United States)

    Casstevens, John M.; Rashed, Abuagela; Plummer, Ronald; Bray, Don; Gates, Rob L.; Lara-Curzio, Edgar; Ferber, Matt K.; Kirkland, Tim

    2001-12-01

    Silicon carbide may well be the best known material for the manufacture of high performance optical components. This material offers many advantages over glasses and metals that have historically been used in high performance optical systems. A combination of extremely high specific stiffness (E/r), high thermal conductivity and outstanding dimensional stability make silicon carbide superior overall to beryllium and low-expansion glass ceramics. A major impediment to wide use of silicon carbide in optical systems has been the cost associated with preliminary shaping and final finishing of silicon carbide. Because silicon carbide is an extremely hard and strong material, precision machining can only be done with expensive diamond tooling on very stiff high quality machine tools. Near-net-shape slip casting of silicon carbide can greatly reduce the cost of silicon carbide mirror substrates but this process still requires significant diamond grinding of the cast components. The process described here begins by machining the component from all special type of graphite. This graphite can rapidly be machined with conventional multi-axis CNC machine tools to achieve any level of complexity and lightweighting required. The graphite is then directly converted completely to silicon carbide with very small and very predictable dimensional change. After conversion to silicon carbide the optical surface is coated with very fine grain CVD silicon carbide which is easily polished to extreme smoothness. Details of the fabrication process are described and photos and performance specifications of an eight-inch elliptical demonstration mirror are provided.

  4. Microstructure and corrosion behavior of a Zr-Sn-Nb-Fe-Cu-O alloy fabricated by α+β quenching processing

    Science.gov (United States)

    Chen, Liangyu; Zhang, Lina; Chai, Linjiang; Yang, Wenlong; Wang, Liqiang; lu, Weijie

    2017-03-01

    In this work, the microstructure of a Zr-Sn-Nb-Fe-Cu-O alloy fabricated by α+β quenching processing (ABQ sample) was investigated by the combined utilization of scanning electron microscopy, electron backscatter diffraction and transmission electron microscopy. The results showed that the polygonal grains evenly distributed in ABQ sample and triangular grains distributed at triple junctions of polygonal grains with densely second phase particles (SPPs). The textures of directions tilted approximately 25° from normal direction and the rolling direction spreading along the {-} were found in the sample, which was also detected in the regularly cold rolled and annealed sample. The occurrence of corrosion kinetics transition of ABQ sample was sight earlier than that of RAX sample. Due to a higher solid solubility of β-Zr, SPPs re-dissolved into β-Zr during α+β annealing and precipitated out afterward in those areas. Finally, discrepant corrosion rate of metal matrix and SPPs led to the formation of protrusions of matrix, which could concentrate stress and generate cracks in the oxide.

  5. Fabrication of Cu2SnS3 thin films by ethanol-ammonium solution process by doctor-blade technique

    Science.gov (United States)

    Wang, Yaguang; Li, Jianmin; Xue, Cong; Zhang, Yan; Jiang, Guoshun; Liu, Weifeng; Zhu, Changfei

    2017-06-01

    In the present study, a low-cost and simple method is applied to fabricate Cu2SnS3 (CTS) thin films. Namely CTS thin films are prepared by a doctor-blade method with a slurry dissolving the Cu2O and SnS powders obtained from CBD reaction solution into ethanol-ammonium solvents. Series of characterization methods including XRD, Raman spectra, SEM and UV-Vis analyses are introduced to investigate the phase structure, morphology and optical properties of CTS thin films. As a result, monoclinic CTS films have been obtained with the disappearance of binary phases CuS and SnS2 while increasing the annealing temperature and time, high quality monoclinic CTS thin films consisting of compact and large grains have been successfully prepared by this ethanol-ammonium method. Moreover, the secondary phase Cu2Sn3S7 is also observed during the annealing process. In addition, the post-annealed CTS film with a band-gap about 0.89 eV shows excellent absorbance between 400 and 1200 nm, which is proper for the bottom layer in multi-junction thin film solar cells. [Figure not available: see fulltext.

  6. Low-voltage large-current ion gel gated polymer transistors fabricated by a "cut and bond" process.

    Science.gov (United States)

    Shao, Xianyi; Bao, Bei; Zhao, Jiaqing; Tang, Wei; Wang, Shun; Guo, Xiaojun

    2015-03-04

    A "cut and bond" process using a commercial die bonder was developed for fabricating ion gel gated organic thin-film transistors (OTFTs). It addresses the issues of damaging or contaminating the channel layer when depositing the ion gel layer on top in conventional fabrication processes. The formed isolated dielectric regions can help to eliminate possible lateral electric field coupling through the dielectric layer when several devices are integrated to construct functional circuits. The fabricated OTFTs provide mA-level ON current, and an ON/OFF current ratio higher than 10(5) with the gate swing voltage of less than 3 V. With the developed process, the ion gel OTFTs are integrated with inorganic light emitting diodes (LEDs) of different colors on plastic substrate using the same die bonder, and the light emission of the LEDs can be modulated in a wide range from dark to high brightness with change of the gate voltage less than 3 V.

  7. Preparation of highly hydrophobic cotton fabrics by modification with bifunctional silsesquioxanes in the sol-gel process

    Science.gov (United States)

    Przybylak, Marcin; Maciejewski, Hieronim; Dutkiewicz, Agnieszka

    2016-11-01

    The surface modification of cotton fabrics was carried out using two types of bifunctional fluorinated silsesquioxanes with different ratios of functional groups. The modification was performed either by one- or two-step process. Two methods, the sol-gel and the dip coating method were used in different configurations. The heat treatment and the washing process were applied after modification. The wettability of cotton fabric was evaluated by measuring water contact angles (WCA). Changes in the surface morphology were examined by scanning electron microscopy (SEM, SEM-LFD) and atomic force microscopy (AFM). Moreover, the modified fabrics were subjected to analysis of elemental composition of the applied coatings using SEM-EDS techniques. Highly hydrophobic textiles were obtained in all cases studied and one of the modifications resulted in imparting superhydrophobic properties. Most of impregnated textiles remained hydrophobic even after multiple washing process which shows that the studied modification is durable.

  8. Radiological audit of remedial action activities at the processing site, transfer site, and Cheney disposal site Grand Junction, Colorado: Audit date, August 9--11, 1993. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1993-08-01

    The Uranium Mill Tailing Remedial Action (UMTRA) Project`s Technical Assistance Contractor (TAC) performed a radiological audit of the Remedial Action Contractor (RAC), MK-Ferguson and CWM Federal Environmental Services, Inc., at the processing site, transfer site, and Cheney disposal site in Grand Junction, Colorado. Jim Hylko and Bill James of the TAC conducted this audit August 9 through 11, 1993. Bob Cornish and Frank Bosiljevec represented the US Department of Energy (DOE). This report presents one programmatic finding, eleven site-specific observations, one good practice, and four programmatic observations.

  9. Batch-processed GdBCO-Ag bulk superconductors fabricated using generic seeds with high trapped fields

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Y., E-mail: ys206@cam.ac.u [Superconductivity Group, Engineering Department, University of Cambridge, CB2 1PZ (United Kingdom); Hari Babu, N. [Brunel Centre for Advanced Solidification Technology (BCAST), Brunel University, West London UB8 3PH (United Kingdom); Iida, K. [Superconducting Group, IFW-Dresden Helmoholtz Str. 20, D-01069 Dresden (Germany); Yeoh, W.K. [Australian Key Centre for Microscopy and Microanalysis, University of Sydney, NSW 2006 (Australia); Dennis, A.R.; Pathak, S.K.; Cardwell, D.A. [Superconductivity Group, Engineering Department, University of Cambridge, CB2 1PZ (United Kingdom)

    2010-09-01

    Large, single grains of Y-Ba-Cu-O (YBCO) have been batch-processed to date by the top seeded melt growth (TSMG) process using NdBCO or SmBCO seed crystals. It has proved difficult, however, to economically batch-process light rare earth (LRE) LRE-Ba-Cu-O bulk high temperature superconductors, which have higher critical current densities and irreversibility fields than YBCO, and therefore greater potential for high field engineering applications. In this paper, we report a novel batch-process based on a cheap, readily available generic seed crystal, developed recently at Cambridge, and a TSMG melt processing technique based on cold seeding in air for the batch fabrication of Gd-Ba-Cu-O-Ag single grains. The superconducting properties of the (LRE)BCO single grains fabricated by this process are, in all respects, equivalent to those processed more conventionally in a reduced oxygen atmosphere.

  10. A Theoretical Model for Predicting Residual Stress Generation in Fabrication Process of Double-Ceramic-Layer Thermal Barrier Coating System.

    Science.gov (United States)

    Song, Yan; Wu, Weijie; Xie, Feng; Liu, Yilun; Wang, Tiejun

    2017-01-01

    Residual stress arisen in fabrication process of Double-Ceramic-Layer Thermal Barrier Coating System (DCL-TBCs) has a significant effect on its quality and reliability. In this work, based on the practical fabrication process of DCL-TBCs and the force and moment equilibrium, a theoretical model was proposed at first to predict residual stress generation in its fabrication process, in which the temperature dependent material properties of DCL-TBCs were incorporated. Then, a Finite Element method (FEM) has been carried out to verify our theoretical model. Afterwards, some important geometric parameters for DCL-TBCs, such as the thickness ratio of stabilized Zirconia (YSZ, ZrO2-8%Y2O3) layer to Lanthanum Zirconate (LZ, La2Zr2O7) layer, which is adjustable in a wide range in the fabrication process, have a remarkable effect on its performance, therefore, the effect of this thickness ratio on residual stress generation in the fabrication process of DCL-TBCs has been systematically studied. In addition, some thermal spray treatment, such as the pre-heating treatment, its effect on residual stress generation has also been studied in this work. It is found that, the final residual stress mainly comes from the cooling down process in the fabrication of DCL-TBCs. Increasing the pre-heating temperature can obviously decrease the magnitude of residual stresses in LZ layer, YSZ layer and substrate. With the increase of the thickness ratio of YSZ layer to LZ layer, magnitudes of residual stresses arisen in LZ layer and YSZ layer will increase while residual stress in substrate will decrease.

  11. A Theoretical Model for Predicting Residual Stress Generation in Fabrication Process of Double-Ceramic-Layer Thermal Barrier Coating System

    Science.gov (United States)

    Song, Yan; Wu, Weijie; Xie, Feng; Liu, Yilun; Wang, Tiejun

    2017-01-01

    Residual stress arisen in fabrication process of Double-Ceramic-Layer Thermal Barrier Coating System (DCL-TBCs) has a significant effect on its quality and reliability. In this work, based on the practical fabrication process of DCL-TBCs and the force and moment equilibrium, a theoretical model was proposed at first to predict residual stress generation in its fabrication process, in which the temperature dependent material properties of DCL-TBCs were incorporated. Then, a Finite Element method (FEM) has been carried out to verify our theoretical model. Afterwards, some important geometric parameters for DCL-TBCs, such as the thickness ratio of stabilized Zirconia (YSZ, ZrO2-8%Y2O3) layer to Lanthanum Zirconate (LZ, La2Zr2O7) layer, which is adjustable in a wide range in the fabrication process, have a remarkable effect on its performance, therefore, the effect of this thickness ratio on residual stress generation in the fabrication process of DCL-TBCs has been systematically studied. In addition, some thermal spray treatment, such as the pre-heating treatment, its effect on residual stress generation has also been studied in this work. It is found that, the final residual stress mainly comes from the cooling down process in the fabrication of DCL-TBCs. Increasing the pre-heating temperature can obviously decrease the magnitude of residual stresses in LZ layer, YSZ layer and substrate. With the increase of the thickness ratio of YSZ layer to LZ layer, magnitudes of residual stresses arisen in LZ layer and YSZ layer will increase while residual stress in substrate will decrease. PMID:28103275

  12. Metal finishing and vacuum processes groups, Materials Fabrication Division progress report, March-May 1984

    Energy Technology Data Exchange (ETDEWEB)

    Dini, J.W.; Romo, J.G.; Jones, L.M.

    1984-07-11

    Progress is reported in fabrication and coating activities being conducted for the weapons program, nuclear test program, nuclear design program, magnetic fusion program, and miscellaneous applications. (DLC)

  13. Synthesis, processing and characterization of shear thickening fluid (STF) impregnated fabric composites

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Tarig A. [Center for Advanced Materials (T-CAM), Tuskegee University, Tuskegee, AL 36088 (United States); Rangari, Vijay K., E-mail: rangariv@tuskegee.edu [Center for Advanced Materials (T-CAM), Tuskegee University, Tuskegee, AL 36088 (United States); Jeelani, Shaik [Center for Advanced Materials (T-CAM), Tuskegee University, Tuskegee, AL 36088 (United States)

    2010-05-15

    Shear thickening is a non-Newtonian fluid behavior defined as the increase of viscosity with the increase in the applied shear rate. The shear thickening fluid (STF) is a combination of hard metal oxide particles suspended in a liquid polymer. This mixture of flowable and hard components at a particular composition, results in a material with remarkable properties. In this manuscript the shear thickening fluid (STF) was prepared by ultrasound irradiation of silica nanoparticles dispersed in liquid polyethylene glycol polymer. The as-prepared STFs have been tested for their rheological and thermal properties. Kevlar and Nylon fabrics were soaked in STF/ethanol solution to make STF/fabric composite. Knife threats and quasistatic penetration tests were performed on the neat fabrics and STF/fabric composite targets for both engineered spike and knife on areal density basis. The results showed that STF impregnated fabrics have better penetration resistance as compared to neat fabrics without affecting the fabric flexibility. This indicates that the addition of STF to the fabric have enhanced the fabric performance and can be used in liquid body armor applications.

  14. Laser-assisted controlled in-diffusion processes for preparation of optical waveguides and ultrashallow semiconductor junctions

    Science.gov (United States)

    Dinescu, Maria; Chitica, N.; Lita, Adriana; Pantelica, D.; Bucur, B.; Ferrari, A.; Maiello, Gabriella; Bertolotti, Mario; Michailova, Galina; Gerardi, C.; Giorgi, Rossella; Dekonimos-Makris, T.; Montecchi, Marco

    1995-03-01

    We present new results in the laser doping of two materials of major interest for applications: LiNbO3 and Si. In both cases a solid dopant source was used. Using a free running ruby laser, we have doped single crystalline lithium niobate with Ti down to 1.5 micrometers . A step- like Ti profile was determined by Rutherford BAckscattering Spectrometry. Irradiating with a cw CO2 laser Si wafers coated with a P-containing paste, n-p junctions were obtained.

  15. Fabrication of UO/sub 2/ microspheres by the hydrolysis process

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Halim, A.S.; Afifi, Y.K.; El-Adham, K.A.

    1987-10-01

    The application of the hydrolysis process to the fabrication of UO/sub 2/ microspheres is described. The process consists of successive steps, such as feed preparation, drop formation and gelation, washing and soaking, drying, reduction and sintering. The effect of washing and soaking conditions on the properties of UO/sub 2/ gel microspheres was investigated. The influence of reduction conditions, such as H/sub 2/ or NH/sub 3/ atmosphere and temperature, on the reduced density of UO/sub 2/ microspheres was studied. The sintering behaviour of UO/sub 2/ microspheres prepared under different conditions of washing and soaking was studied in an atmosphere of Ar or NH/sub 3/ at relatively low temperatures (1100...1400/sup 0/C). It was found that washing with ammonia solution and soaking in ammonia solution before washing result in good sinterable microspheres with a high specific surface area (10...12 m/sup 2//g) and small crystallite size (85...110 A). Dense UO/sub 2/ microspheres (> 95% th.d.) can be prepared by sintering in Ar at 1100/sup 0/C for 2 h.

  16. Fabrication Processes to Generate Concentration Gradients in Polymer Solar Cell Active Layers.

    Science.gov (United States)

    Inaba, Shusei; Vohra, Varun

    2017-05-09

    Polymer solar cells (PSCs) are considered as one of the most promising low-cost alternatives for renewable energy production with devices now reaching power conversion efficiencies (PCEs) above the milestone value of 10%. These enhanced performances were achieved by developing new electron-donor (ED) and electron-acceptor (EA) materials as well as finding the adequate morphologies in either bulk heterojunction or sequentially deposited active layers. In particular, producing adequate vertical concentration gradients with higher concentrations of ED and EA close to the anode and cathode, respectively, results in an improved charge collection and consequently higher photovoltaic parameters such as the fill factor. In this review, we relate processes to generate active layers with ED-EA vertical concentration gradients. After summarizing the formation of such concentration gradients in single layer active layers through processes such as annealing or additives, we will verify that sequential deposition of multilayered active layers can be an efficient approach to remarkably increase the fill factor and PCE of PSCs. In fact, applying this challenging approach to fabricate inverted architecture PSCs has the potential to generate low-cost, high efficiency and stable devices, which may revolutionize worldwide energy demand and/or help develop next generation devices such as semi-transparent photovoltaic windows.

  17. Fabrication Processes to Generate Concentration Gradients in Polymer Solar Cell Active Layers

    Science.gov (United States)

    Inaba, Shusei; Vohra, Varun

    2017-01-01

    Polymer solar cells (PSCs) are considered as one of the most promising low-cost alternatives for renewable energy production with devices now reaching power conversion efficiencies (PCEs) above the milestone value of 10%. These enhanced performances were achieved by developing new electron-donor (ED) and electron-acceptor (EA) materials as well as finding the adequate morphologies in either bulk heterojunction or sequentially deposited active layers. In particular, producing adequate vertical concentration gradients with higher concentrations of ED and EA close to the anode and cathode, respectively, results in an improved charge collection and consequently higher photovoltaic parameters such as the fill factor. In this review, we relate processes to generate active layers with ED–EA vertical concentration gradients. After summarizing the formation of such concentration gradients in single layer active layers through processes such as annealing or additives, we will verify that sequential deposition of multilayered active layers can be an efficient approach to remarkably increase the fill factor and PCE of PSCs. In fact, applying this challenging approach to fabricate inverted architecture PSCs has the potential to generate low-cost, high efficiency and stable devices, which may revolutionize worldwide energy demand and/or help develop next generation devices such as semi-transparent photovoltaic windows. PMID:28772878

  18. The Impact of Standard Semiconductor Fabrication Processes on Polycrystalline Nb Thin Film Surfaces

    Science.gov (United States)

    Brown, Ari David; Barrentine, Emily M.; Moseley, Samuel H.; Noroozian, Omid; Stevenson, Thomas

    2011-01-01

    Polycrystalline superconducting Nb thin films are extensively used for submillimeter and millimeter transmission line applications and, less commonly, used in microwave kinetic inductance detector (MKID) applications. The microwave and mm-wave loss in these films is impacted, in part, by the presence of surface nitrides and oxides. In this study, glancing incidence x-ray diffraction was used to identify the presence of niobium nitride and niobium monoxide surface layers on Nb thin films which had been exposed to chemicals used in standard photolithographic processing. A method of mitigating the presence of ordered niobium monoxide surface layers is presented. Furthermore, we discuss the possibility of using glancing incidence x-ray diffraction as a non-destructive diagnostic tool for evaluating the quality of Nb thin films used in MKIDs and transmission lines. For a given fabrication process, we have both the x-ray diffraction data of the surface chemistry and a measure of the mm-wave and microwave loss, the latter being made in superconducting resonators.

  19. Fabrication of a multifunctional carbon nanotube "cotton" yarn by the direct chemical vapor deposition spinning process.

    Science.gov (United States)

    Zhong, Xiao-Hua; Li, Ya-Li; Feng, Jian-Min; Kang, Yan-Ru; Han, Shuai-Shuai

    2012-09-21

    A continuous cotton-like carbon nanotube fiber yarn, consisting of multiple threads of high purity double walled carbon nanotubes, was fabricated in a horizontal CVD gas flow reactor with water vapor densification by the direct chemical vapor deposition spinning process. The water vapor interaction leads to homogeneous shrinking of the CNT sock-like assembly in the gas flow. This allows well controlled continuous winding of the dense thread inside the reactor. The CNT yarn is quite thick (1-3 mm), has a highly porous structure (99%) while being mechanically strong and electrically conductive. The water vapor interaction leads to homogeneous oxidation of the CNTs, offering the yarn oxygen-functionalized surfaces. The unique structure and surface of the CNT yarn provide it multiple processing advantages and properties. It can be mechanically engineered into a dense yarn, infiltrated with polymers to form a composite and mixed with other yarns to form a blend, as demonstrated in this research. Therefore, this CNT yarn can be used as a "basic yarn" for various CNT based structural and functional applications.

  20. A rapid one-step electrodeposition process for fabrication of superhydrobic surfaces on anode and cathode

    Institute of Scientific and Technical Information of China (English)

    郝丽梅; 闫小乐; 解忧; 张涛; 陈志

    2016-01-01

    This work presents a method to solve the weak solubility of zinc chloride (ZnCl2) in the ethanol by adding some reasonable water into an ethanol electrolyte containing ZnCl2and myristic acid (CH3(CH2)12COOH). A rapid one-step electrodeposition process was developed to fabricate anodic (2.5 min) and cathodic (40 s) superhydrophobic surfaces of copper substrate (contact angle more than 150°) in an aqueous ethanol electrolyte. Morphology, composition, chemical structure and superhydrophobicity of these superhydrophobic surfaces were investigated by SEM, FTIR, XRD, and contact angle measurement, respectively. The results indicate that water ratio of the electrolyte can reduce the required deposition time, superhydrophobic surface needs over 30 min with anhydrous electrolyte, while it needs only 2.5 min with electrolyte including 10 mL water, and the maximum contact angle of anodic surface is 166° and that of the cathodic surface is 168°. Two copper electrode surfaces have different reactions in the process of electrodeposition time, and the anodic copper surface covers copper myristate (Cu[CH3(CH2)12COO]2) and cupric chloride (CuCl); while, zinc myristate (Zn[CH3(CH2)12COO]2) and pure zinc (Zn) appear on the cathodic surface.

  1. Effects of heat treatment process for blanket fabrication on mechanical properties of F82H

    Energy Technology Data Exchange (ETDEWEB)

    Hirose, T. E-mail: hiroset@fusion.naka.jaeri.go.jp; Shiba, K.; Sawai, T.; Jitsukawa, S.; Akiba, M

    2004-08-01

    The objectives of this work are to evaluate the effects of thermal history corresponding to a blanket fabrication process on Reduced Activation Ferritic/Martensitic steel (RAF/Ms) microstructure, and to establish appropriate Hot Isostatic Pressing (HIP) conditions without degradation in the microstructures. One of RAF/Ms F82H and its modified versions were investigated by metallurgical methods after isochronal heat treatments up to 1473 K simulating HIP thermal history. Although conventional F82H showed significant grain growth after conventional solid HIP conditions, F82H with 0.1 wt% tantalum maintained a fine grain structure after the same heat treatment. It is considered that the grain coarsening was caused by dissolution of tantalum-carbide which immobilizes grain boundaries. On the other hands, conventional RAF/Ms with coarse grains were recovered by post HIP normalizing at temperatures below the TaC solvus temperature. This process can refine the grain size of F82H to more than ASTM grain size number 7.

  2. Binder Jetting: A Novel NdFeB Bonded Magnet Fabrication Process

    Science.gov (United States)

    Paranthaman, M. Parans; Shafer, Christopher S.; Elliott, Amy M.; Siddel, Derek H.; McGuire, Michael A.; Springfield, Robert M.; Martin, Josh; Fredette, Robert; Ormerod, John

    2016-07-01

    The goal of this research is to fabricate near-net-shape isotropic (Nd)2Fe14B-based (NdFeB) bonded magnets using a three dimensional printing process to compete with conventional injection molding techniques used for bonded magnets. Additive manufacturing minimizes the waste of critical materials and allows for the creation of complex shapes and sizes. The binder jetting process works similarly to an inkjet printer. A print-head passes over a bed of NdFeB powder and deposits a polymer binding agent to bind the layer of particles together. The bound powder is then coated with another layer of powder, building the desired shape in successive layers of bonded powder. Upon completion, the green part and surrounding powders are placed in an oven at temperatures between 100°C and 150°C for 4-6 h to cure the binder. After curing, the excess powder can be brushed away to reveal the completed "green" part. Green magnet parts were then infiltrated with a clear urethane resin to achieve the measured density of the magnet of 3.47 g/cm3 close to 46% relative to the NdFeB single crystal density of 7.6 g/cm3. Magnetic measurements indicate that there is no degradation in the magnetic properties. This study provides a new pathway for preparing near-net-shape bonded magnets for various magnetic applications.

  3. Fabrication and characterization of LiH ceramic pebbles by wet process

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Maoqiao; Zhang, Yingchun, E-mail: zycustb@163.com; Hong, Ming; Liu, Zhiang; Leng, Jiaxun; Zhang, Yun; Zhang, Jialiang; Wang, Wenchang

    2014-09-15

    Lithium hydride (LiH) ceramic pebbles, a new potential tritium breeding material in fusion–fission or fusion reactor blanket, were prepared by wet process for the first time. XRD results showed that LiOH, LiOH·H{sub 2}O, Li{sub 2}CO{sub 3} and Li{sub 2}O were found in the surface of LiH pebbles. However, the pure phase of LiH pebbles without cracks could be obtained by paraffin wax coating technique. The average value (a.v.) of the sphericity and the diameter were 1.01 and 0.98 mm, respectively. The LiH pebbles sintered at 450 °C for 3 h under 80 ml/min flowing argon, reached ∼92.3% of the theoretical density, with the grain size of 5.59 μm (a.v.). And the crush load was measured to be 15 N on average. The described wet process exhibited multiple advantages for fabricating LiH pebbles.

  4. Characterization of Deciliation-Regeneration Process of Tetrahymena Pyriformis for Cellular Robot Fabrication

    Institute of Scientific and Technical Information of China (English)

    Dal Hyung Kim; Sean E. Brigandi; Paul Kim; Doyoung Byun; Min Jun Kim

    2011-01-01

    Artificial magnetotactic Tetrahymena pyriformis GL (T. pyriformis) cells were created by the internalization of iron oxide nano particles and became controllable with a time-varying external magnetic field. Thus, T. pyriformis can be utilized as a cellular robot to conduct micro-scale tasks such as transportation and manipulation. To complete these tasks, loading inorganic or organic materials onto the cell body is essential, but functionalization of the cell membrane is obstructed by their motile organelles, cilia. Dibucaine HCl, a local anesthetic, removes the cilia from the cell body, and the functional group would be absorbed more efficiently during cilia regeneration. In this paper, we characterize the recovery of artificial magnetotactic T.pyriformis after the deciliation process to optimize a cellular robot fabrication process. After sufficient time to recover, the motility rate and the average velocity of the deciliated cells were six and ten percent lower than that of non-deciliated cells, respectively. We showed that the motile cells after recovery can still be controlled using magnetotaxis, making T. pyriformis a good candidate to be used as a cellular robot.

  5. Pore Formation Process of Porous Ti3SiC2 Fabricated by Reactive Sintering

    Directory of Open Access Journals (Sweden)

    Huibin Zhang

    2017-02-01

    Full Text Available Porous Ti3SiC2 was fabricated with high purity, 99.4 vol %, through reactive sintering of titanium hydride (TiH2, silicon (Si and graphite (C elemental powders. The reaction procedures and the pore structure evolution during the sintering process were systematically studied by X-ray diffraction (XRD and scanning electron microscope (SEM. Our results show that the formation of Ti3SiC2 from TiH2/Si/C powders experienced the following steps: firstly, TiH2 decomposed into Ti; secondly, TiC and Ti5Si3 intermediate phases were generated; finally, Ti3SiC2 was produced through the reaction of TiC, Ti5Si3 and Si. The pores formed in the synthesis procedure of porous Ti3SiC2 ceramics are derived from the following aspects: interstitial pores left during the pressing procedure; pores formed because of the TiH2 decomposition; pores formed through the reactions between Ti and Si and Ti and C powders; and the pores produced accompanying the final phase synthesized during the high temperature sintering process.

  6. Fabrication of biomimetic hydrophobic films with corrosion resistance on magnesium alloy by immersion process

    Energy Technology Data Exchange (ETDEWEB)

    Liu Yan, E-mail: liuyan2000@jlu.edu.cn [Key Laboratory for Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022 (China); Lu Guolong; Liu Jindan; Han Zhiwu; Liu Zhenning [Key Laboratory for Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022 (China)

    2013-01-01

    Highlights: Black-Right-Pointing-Pointer We have developed a facile and simple method of creating a hydrophobic surface on a magnesium alloy by an immersion process at room temperature. Black-Right-Pointing-Pointer The distribution of the micro-structure and the roughness of the surface play critical roles in transforming from hydrophilic to hydrophobic. Black-Right-Pointing-Pointer The hydrophobic coatings possess better corrosion resistance than magnesium alloy matrix. - Abstract: Biomimetic hydrophobic films of crystalline CeO{sub 2} were prepared on magnesium alloy by an immersion process with cerium nitrate solution and then modified with DTS (CH{sub 3}(CH{sub 2}){sub 11}Si(OCH{sub 3}){sub 3}). The CeO{sub 2} films fabricated with 20-min immersion yield a water contact angle of 137.5 {+-} 2 Degree-Sign , while 20-min DTS treatment on top of CeO{sub 2} can further enhance the water contact angle to 146.7 {+-} 2 Degree-Sign . Then corrosion-resistant property of these prepared films against NaCl solution was investigated and elucidated using electrochemical measurements.

  7. All polymer, injection molded nanoslits, fabricated through two-level UV-LIGA processes

    DEFF Research Database (Denmark)

    Østergaard, Peter Friis; Matteucci, Marco; Marie, Rodolphe;

    2012-01-01

    Micro- and nanofluidic systems fabricated in silicon and glass substrates are expensive and have long production cycles. To minimize the time used by researchers to fabricate their systems, rather than using them, medium to high volume throughput of specific chips, containing fluidic channels in ...

  8. Cluster B personality symptoms in persons at genetic risk for schizophrenia are associated with social competence and activation of the right temporo-parietal junction during emotion processing.

    Science.gov (United States)

    Goldschmidt, Micaela Giuliana; Villarreal, Mirta Fabiana; de Achával, Delfina; Drucaroff, Lucas Javier; Costanzo, Elsa Yolanda; Castro, Mariana Nair; Pahissa, Jaime; Camprodon, Joan; Nemeroff, Charles; Guinjoan, Salvador Martín

    2014-01-30

    Personality disorders are common in nonpsychotic siblings of patients with schizophrenia, and some personality traits in this group may be associated with an increased risk for full-blown psychosis. We sought to establish if faulty right-hemisphere activation induced by social cognitive tasks, as previously described in patients with schizophrenia, is associated with specific personality symptoms in their unaffected siblings. We observed that cluster B personality symptoms in this group were inversely related to activation in the right temporo parietal junction (rTPJ, a structure critical in social cognitive processing) in response to a basic emotion processing task and also to social competence, whereas in contrast to our initial hypothesis, cluster A traits were not associated with right hemisphere activation during emotion processing or with social competence. These findings suggest the existence of clinical traits in at-risk individuals which share a common neurobiological substrate with schizophrenia, in regards to social performance.

  9. Development of Impregnated Agglomerate Pelletization (IAP) process for fabrication of (Th,U)O 2 mixed oxide pellets

    Science.gov (United States)

    Khot, P. M.; Nehete, Y. G.; Fulzele, A. K.; Baghra, Chetan; Mishra, A. K.; Afzal, Mohd.; Panakkal, J. P.; Kamath, H. S.

    2012-01-01

    Impregnated Agglomerate Pelletization (IAP) technique has been developed at Advanced Fuel Fabrication Facility (AFFF), BARC, Tarapur, for manufacturing (Th, 233U)O 2 mixed oxide fuel pellets, which are remotely fabricated in hot cell or shielded glove box facilities to reduce man-rem problem associated with 232U daughter radionuclides. This technique is being investigated to fabricate the fuel for Indian Advanced Heavy Water Reactor (AHWR). In the IAP process, ThO 2 is converted to free flowing spheroids by powder extrusion route in an unshielded facility which are then coated with uranyl nitrate solution in a shielded facility. The dried coated agglomerate is finally compacted and then sintered in oxidizing/reducing atmosphere to obtain high density (Th,U)O 2 pellets. In this study, fabrication of (Th,U)O 2 mixed oxide pellets containing 3-5 wt.% UO 2 was carried out by IAP process. The pellets obtained were characterized using optical microscopy, XRD and alpha autoradiography. The results obtained were compared with the results for the pellets fabricated by other routes such as Coated Agglomerate Pelletization (CAP) and Powder Oxide Pelletization (POP) route.

  10. Development and demonstration of manufacturing processes for fabricating graphite/Larc-160 polyimide structural elements, part 4, paragraph C

    Science.gov (United States)

    1981-01-01

    Progress in the development of processes for production of Celion/LARC-160 graphite-polyimide materials, quality control methods, and the fabrication of Space Shuttle composite structure components is reported. The formulation and processing limits for three batches of resin are presented. Process improvements for simplification of the imidizing and autoclave cure cycles are described. Imidized and autoclave cured test panels were prepared. Celion/LARC-160 cure process verification and the fabrication of honeycomb sandwich panel elements and skin/stringer panels are described. C-scans of laminates imidized at 163 C to 218 C for periods from 30 to 180 minutes, and of process verification laminates made from different batches of prepreg are presented. Failure modes and load/strain characteristics of sandwich elements and C-scans of stringer to skin bond joints are also given.

  11. Measure Guideline: Optimizing the Configuration of Flexible Duct Junction Boxes

    Energy Technology Data Exchange (ETDEWEB)

    Beach, R. [IBACOS, Inc., Pittsburgh, PA (United States); Burdick, A. [IBACOS, Inc., Pittsburgh, PA (United States)

    2014-03-01

    This measure guideline offers additional recommendations to heating, ventilation, and air conditioning (HVAC) system designers for optimizing flexible duct, constant-volume HVAC systems using junction boxes within Air Conditioning Contractors of America (ACCA) Manual D guidance. IBACOS used computational fluid dynamics software to explore and develop guidance to better control the airflow effects of factors that may impact pressure losses within junction boxes among various design configurations. These recommendations can help to ensure that a system aligns more closely with the design and the occupants' comfort expectations. Specifically, the recommendations described herein show how to configure a rectangular box with four outlets, a triangular box with three outlets, metal wyes with two outlets, and multiple configurations for more than four outlets. Designers of HVAC systems, contractors who are fabricating junction boxes on site, and anyone using the ACCA Manual D process for sizing duct runs will find this measure guideline invaluable for more accurately minimizing pressure losses when using junction boxes with flexible ducts.

  12. Experimental and Numerical Simulation Research on Micro-Gears Fabrication by Laser Shock Punching Process

    Directory of Open Access Journals (Sweden)

    Huixia Liu

    2015-07-01

    Full Text Available The aim of this paper is to fabricate micro-gears via laser shock punching with Spitlight 2000 Nd-YAG Laser, and to discuss effects of process parameters namely laser energy, soft punch properties and blank-holder on the quality of micro-gears deeply. Results show that dimensional accuracy is the best shocked at 1690 mJ. Tensile fracture instead of shear fracture is the main fracture mode under low laser energy. The soft punch might cause damage to punching quality when too high energy is employed. Appropriate thickness and hardness of soft punch is necessary. Silica gel with 200 µm in thickness is beneficial to not only homogenize energy but also propagate the shock wave. Polyurethane films need more energy than silica gel with the same thickness. In addition, blank-holders with different weight levels are used. A heavier blank-holder is more beneficial to improve the cutting quality. Furthermore, the simulation is conducted to reveal typical stages and the different deformation behavior under high and low pulse energy. The simulation results show that the fracture mode changes under lower energy.

  13. Highly Magneto-Responsive Elastomeric Films Created by a Two-Step Fabrication Process

    KAUST Repository

    Marchi, Sophie

    2015-08-24

    An innovative method for the preparation of elastomeric magnetic films with increased magneto-responsivity is presented. Polymeric films containing aligned magnetic microchains throughout their thickness are formed upon the magnetophoretic transport and assembly of microparticles during polymer curing. The obtained films are subsequently magnetized at a high magnetic field of 3 T directed parallel to the orientation of the microchains. We prove that the combination of both alignment of the particles along a favorable direction during curing and the subsequent magnetization of the solid films induces an impressive increase of the films’ deflection. Specifically, the displacements reach few millimeters, up to 85 times higher than those of the nontreated films with the same particle concentration. Such a process can improve the performance of the magnetic films without increasing the amount of magnetic fillers and, thus, without compromising the mechanical properties of the resulting composites. The proposed method can be used for the fabrication of magnetic films suitable as components in systems in which large displacements at relatively low magnetic fields are required, such as sensors and drug delivery or microfluidic systems, especially where remote control of valves is requested to achieve appropriate flow and mixing of liquids.

  14. Focused ion beam processing to fabricate ohmic contact electrodes on a bismuth nanowire for Hall measurements.

    Science.gov (United States)

    Murata, Masayuki; Hasegawa, Yasuhiro

    2013-09-26

    Ohmic contact electrodes for four-wire resistance and Hall measurements were fabricated on an individual single-crystal bismuth nanowire encapsulated in a cylindrical quartz template. Focused ion beam processing was utilized to expose the side surfaces of the bismuth nanowire in the template, and carbon and tungsten electrodes were deposited on the bismuth nanowire in situ to achieve electrical contacts. The temperature dependence of the four-wire resistance was successfully measured for the bismuth nanowire, and a difference between the resistivities of the two-wire and four-wire methods was observed. It was concluded that the two-wire method was unsuitable for estimation of the resistivity due to the influence of contact resistance, even if the magnitude of the bismuth nanowire resistance was greater than the kilo-ohm order. Furthermore, Hall measurement of a 4-μm-diameter bismuth microwire was also performed as a trial, and the evaluated temperature dependence of the carrier mobility was in agreement with that for bulk bismuth, which indicates that the carrier mobility was successfully measured using this technique. PACS: 81.07.Gf.

  15. Focused ion beam fabrication of spintronic nanostructures: an optimization of the milling process

    Energy Technology Data Exchange (ETDEWEB)

    Urbanek, M; UhlIr, V; Babor, P; Spousta, J; Sikola, T [Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technicka 2, 616 69 Brno (Czech Republic); KolIbalova, E; HrncIr, T, E-mail: urbanek@fme.vutbr.cz [TESCAN, s.r.o., Libusina trIda 21, 623 00 Brno (Czech Republic)

    2010-04-09

    Focused ion beam (FIB) milling has been used to fabricate magnetic nanostructures (wires, squares, discs) from single magnetic layers (Co, permalloy) and spin-valve (permalloy/Cu/Co) multilayers (thicknesses 5-50 nm) prepared by ion beam sputtering deposition. Milled surfaces of metallic thin films typically exhibit residual roughness, which is also transferred onto the edges of the milled patterns. This can lead to domain wall pinning and influence the magnetization behaviour of the nanostructures. We have investigated the milling process and the influence of the FIB parameters (incidence angle, dwell time, overlap and ion beam current) on the roughness of the milled surface. It has been found that the main reasons for increased roughness are different sputter yields for various crystallographic orientations of the grains in polycrystalline magnetic thin films. We have found that the oblique ion beam angle, long dwell time and overlap < 1 are favourable parameters for suppression of this intrinsic roughness. Finally, we have shown how to determine the ion dose necessary to mill through the whole thin film up to the silicon substrate from scanning electron microscopy (SEM) images only.

  16. Fast-dissolving core-shell composite microparticles of quercetin fabricated using a coaxial electrospray process.

    Directory of Open Access Journals (Sweden)

    Chen Li

    Full Text Available This study reports on novel fast-dissolving core-shell composite microparticles of quercetin fabricated using coaxial electrospraying. A PVC-coated concentric spinneret was developed to conduct the electrospray process. A series of analyses were undertaken to characterize the resultant particles in terms of their morphology, the physical form of their components, and their functional performance. Scanning and transmission electron microscopies revealed that the microparticles had spherical morphologies with clear core-shell structure visible. Differential scanning calorimetry and X-ray diffraction verified that the quercetin active ingredient in the core and sucralose and sodium dodecyl sulfate (SDS excipients in the shell existed in the amorphous state. This is believed to be a result of second-order interactions between the components; these could be observed by Fourier transform infrared spectroscopy. In vitro dissolution and permeation studies showed that the microparticles rapidly released the incorporated quercetin within one minute, and had permeation rates across the sublingual mucosa around 10 times faster than raw quercetin.

  17. Processing and fabrication of YBa2Cu3O(x)/Ag composite wires and coils

    Science.gov (United States)

    Ferrando, W. A.; Divecha, A. P.; Mansour, A. N.; Karmarkar, S. D.; Balachandran, U.; Dorris, S. E.; Dusek, J. T.; Picciolo, J. J.; Singh, J. P.; Poeppel, R. B.

    1990-11-01

    Silver was added to YBa2Cu3O(x) (123) powder by a melt technique using AgNO3 and heated to approx. 600 C to decompose the nitrate. This process yields 123 powder that is uniformly coated with Ag, as indicated by optical and scanning electron microscopy (SEM). The composite power is formed into rods (approx. 4 mm diameter) via drawing and swaging through conical converging dies. Wires of finer diameter (approx. 1 mm) and substantially greater linear uniformity were produced by slurry extrusion of the composite powder in a polymeric vehicle. Transport critical current density, J sub c, of these wires at present is about 750 A/sq cm. This value may be expected to rise due to further reduction of second phase impurities localized at grain boundaries and better understanding of the Ag/superconductor interface. The wire fabrication is described in some detail and discusses the results of microscopic analyses by scanning electron microscopy (SEM), x ray photoemission spectroscopy (XPS), and x ray diffraction (XRD).

  18. Energy harvesting using piezoelectric thick films fabricated by a sol-gel process

    Energy Technology Data Exchange (ETDEWEB)

    Shih, J.L. [McGill Univ., Montreal, PQ (Canada). Dept. of Electrical and Computer Engineering; Kobayashi, M.; Moisan, J.F.; Jen, C.K. [National Research Council of Canada, Boucherville, PQ (Canada). Industrial Materials Inst.

    2008-07-01

    Energy harvesting has been touted as a promising technology to power wireless devices. One of the common energies to be harvested is induced by mechanical vibrations. Piezoelectric materials are often used to get such energy. This study focused on a vibration-based energy harvesting device. Very flexible vibrators using lead-zirconate-titanate (PZT) ceramics were needed. Therefore, a sol-gel spray technology was used to fabricate PZT thick film directly onto metal membranes to serve as mechanical vibrators. The sol-gel process is an economical approach with excellent mass production appeal for both unimorph and bimorph sensors. For this study, the density of the PZT film was less than 85 per cent of the bulk PZT. Using a 20 mm diameter unimorph, the voltage generated from a 5 mm deflection displacement was 13.6 volts peak-to-peak at 10 Hz. With a load resistance of 150 K ohms, the measured average power generated by this sensor was estimated to be 41 {mu}W. A vibration test that lasted for 60 days with a frequency of 10 Hz and at a displacement of approximately 1 mm showed that the sensor is both durable and rugged. 14 refs., 7 figs.

  19. Fabrication process and electromagnetic wave absorption characterization of a CNT/Ni/epoxy nanocomposite.

    Science.gov (United States)

    Ryu, Seongwoo; Mo, Chan Bin; Lee, Haeshin; Hong, Soon Hyung

    2013-11-01

    Since carbon nanotube (CNT) was first discovered in 1991, it has been considered as a viable type of conductive filler for electromagnetic wave absorption materials in the GHz range. In this paper, pearl-necklace-structure CNT/Ni nano-powders were fabricated by a polyol process as conductive fillers. Compared to synthesized CNT, pearl-necklace Ni-decorated CNT increased the electrical conductivity by an order of 1 due to the enhancement of the Ni-conductive network. Moreover, the decorated Ni particles prevented the agglomeration of CNTs by counterbalancing the Van der Walls interaction between the CNTs. A CNT/Ni nanocomposite showed a homogeneous dispersion in an epoxy-based matrix. This enhanced physical morphology and electrical properties lead to an increase in the loss tangent and reflection loss in the CNT/Ni/Epoxy nanocomposite compared to these characteristics of a CNT/Epoxy nanocomposite in range of 8-12 GHz. The electromagnetic wave absorption properties of CNT/Ni/epoxy nanocomposites will provide enormous opportunities for electronic applications where lightweight EMI shielding or electro-magnetic wave absorption properties are necessary.

  20. Fabrication of hydrophilic paclitaxel-loaded PLA-PEG-PLA microparticles via SEDS process

    Institute of Scientific and Technical Information of China (English)

    Ping OUYANG; Yun-qing KANG; Guang-fu YIN; Zhong-bing HUANG; Ya-dong YAO; Xiao-ming LIAO

    2009-01-01

    In this work, chemically bonded poly(D, L-lactide)-polyethylene glycol-poly(D, L-lactide) (PLA-PEG-PLA) triblock copolymers with various PEG contents and PLA homopolymer were synthesized via melt polymerization, and were confirmed by FTIR and 1 H-NMR results. The molecular weight and polydispersity of the synthesized PLA and PLA-PEG-PLA copolymers were investigated by gel permeation chromatography. Hydro-philicity of the copolymers was identified by contact angle measurement. PLA-PEG-PLA and PLA microparticles loaded with and without PTX were then produced via solution enhanced dispersion by supercritical CO2 (SEDS) process. The effect of the PEG content on the particle size distribution, morphology, drug load, and encapsulation efficiency of the fabricated microparticles was also studied. Results indicate that PLA and PLA-PEG-PLA micropar-ticles all exhibit sphere-like shape with smooth surface, when PEG content is relatively low. The produced microparticles have narrow particle size distributions and small particle sizes. The drug load and encapsulation efficiency of the produced microparticles decreases with higher PEG content in the copolymer matrix. Moreover, high hydrophilicity is found when PEG is chemically attached to originally hydrophobic PLA, providing the produced drug-loaded microparticles with high hydrophi-licity, biocompatibility, and prolonged circulation time, which are considered of vital importance for vessel-circulating drug delivery system.

  1. Low-loss titanium dioxide waveguides and resonators using a dielectric lift-off fabrication process.

    Science.gov (United States)

    Evans, Christopher C; Liu, Chengyu; Suntivich, Jin

    2015-05-04

    We present a bi-layer lift-off fabrication approach to create low-loss amorphous titanium dioxide (TiO2) integrated optical waveguides and resonators for visible and near-infrared applications. This approach achieves single-mode waveguide losses as low as 7.5 dB/cm around 633 nm and 1.2 dB/cm around 1550 nm, a factor of 4 improvement over previous reports, without the need to optimize etching conditions. Depositing a secondary 260-nm TiO2 layer can reduce losses further, with the optimized process yielding micro-ring resonators with loaded quality factors as high as 1.5 × 10(5) around 1550 nm and 1.6×10(5) around 780 nm. These losses render our TiO2 devices suitable for visible and telecommunications applications; in addition, the simplicity of this lift-off approach is broadly applicable to other novel material platforms, particularly using near-visible wavelengths.

  2. Fabrication of Copper-Rich Cu-Al Alloy Using the Wire-Arc Additive Manufacturing Process

    Science.gov (United States)

    Dong, Bosheng; Pan, Zengxi; Shen, Chen; Ma, Yan; Li, Huijun

    2017-09-01

    An innovative wire-arc additive manufacturing (WAAM) process is used to fabricate Cu-9 at. pct Al on pure copper plates in situ, through separate feeding of pure Cu and Al wires into a molten pool, which is generated by the gas tungsten arc welding (GTAW) process. After overcoming several processing problems, such as opening the deposition molten pool on the extremely high-thermal conductive copper plate and conducting the Al wire into the molten pool with low feed speed, the copper-rich Cu-Al alloy was successfully produced with constant predesigned Al content above the dilution-affected area. Also, in order to homogenize the as-fabricated material and improve the mechanical properties, two further homogenization heat treatments at 1073 K (800 °C) and 1173 K (900 °C) were applied. The material and mechanical properties of as-fabricated and heat-treated samples were compared and analyzed in detail. With increased annealing temperatures, the content of precipitate phases decreased and the samples showed gradual improvements in both strength and ductility with little variation in microstructures. The present research opened a gate for in-situ fabrication of Cu-Al alloy with target chemical composition and full density using the additive manufacturing process.

  3. Development of automated welding process for field fabrication of thick walled pressure vessels. Fourth quarter, FY 1980

    Energy Technology Data Exchange (ETDEWEB)

    1980-12-19

    Progress is reported in research on the automated welding of heavy steel plate for the fabrication of pressure vessels. Information is included on: torch and shield adaptation; mechanical control of the welding process; welding parameters; joint design; filler wire optimizaton; nondestructive testing of welds; and weld repair. (LCL)

  4. 10 CFR 140.13a - Amount of financial protection required for plutonium processing and fuel fabrication plants.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Amount of financial protection required for plutonium... of financial protection required for plutonium processing and fuel fabrication plants. (a) Each holder of a license issued pursuant to part 70 of this chapter to possess and use plutonium at...

  5. Automated spray coating process for the fabrication of large-area artificial opals on textured substrates.

    Science.gov (United States)

    Sprafke, Alexander N; Schneevoigt, Daniela; Seidel, Sophie; Schweizer, Stefan L; Wehrspohn, Ralf B

    2013-05-06

    3D photonic crystals, such as opals, have been shown to have a high potential to increase the efficiency of solar cells by enabling advanced light management concepts. However, methods which comply with the demands of the photovoltaic industry for integration of these structures, i. e. the fabrication in a low-cost, fast, and large-scale manner, are missing up to now. In this work, we present the spray coating of a colloidal suspension on textured substrates and subsequent drying. We fabricated opaline films of much larger lateral dimensions and in much shorter times than what is possible using conventional opal fabrication methods.

  6. Solution processed Al doped ZnO film fabrication through electrohydrodynamic atomization

    Energy Technology Data Exchange (ETDEWEB)

    Muhammad, Nauman Malik [School of Mechatronics Engineering, Jeju National University, Jeju (Korea, Republic of); Pakistan Atomic Energy Commission, PO-Box, 1114, Islamabad (Pakistan); Duraisamy, Navaneethan [School of Mechatronics Engineering, Jeju National University, Jeju (Korea, Republic of); Dang, Hyun-Woo [School of Electronic Engineering, Jeju National University, Jeju (Korea, Republic of); Jo, Jeongdai [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of); Choi, Kyung-Hyun, E-mail: amm@jejunu.ac.kr [School of Mechatronics Engineering, Jeju National University, Jeju (Korea, Republic of)

    2012-08-01

    In this study, highly transparent, 250 nm thick films of Aluminum doped Zinc-oxide (ZnO:Al) are achieved on glass substrates at ambient conditions through a solution processing technique called electrohydrodynamic atomization. A 10 wt.% monodispersed solution containing 6% ZnO:Al nanoparticles (ZnO/Al{sub 2}O{sub 3}) in ethanol has been synthesized first and then used in the deposition process as the working solution. Pure and uniform transparent films with an average transmittance of 93% have been deposited with crystal structure exhibiting both zincite and gahnite phases. Surface composition purity has been confirmed using X-ray photoelectron spectroscopy technique and the clear indication of Zn-2p and Al-2p peaks confirms surface integrity. Fourier Transform Infrared analysis further confirms the presence of aluminum in the samples. The electrical properties are studied by recording and analyzing the current-voltage (I-V) measurements and the resistivity has been estimated from the slope of the IV-curve which is approximately 25 m{Omega}.cm. The layer roughness has been characterized using atomic force microscopy. - Highlights: Black-Right-Pointing-Pointer Aluminum doped Zinc oxide (ZnO:Al) films are made via electrohydrodynamic atomization. Black-Right-Pointing-Pointer ZnO:Al nano-particle ink is used to form thin films in single step at room conditions. Black-Right-Pointing-Pointer Scanning electron and atomic force microscopes confirm fine layer characteristics. Black-Right-Pointing-Pointer X-ray photoelectron and Fourier Transform-Infrared spectroscope confirm film purity. Black-Right-Pointing-Pointer Transparent and conductive films have been fabricated with wurtzite structure.

  7. Report on cheap processes for fabrication of silicon solar cells of high efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Safir, Y.; Proctor, W.G.; Leistiko, O.

    1984-01-01

    The pingroject is aimed at develop a process for fabrication of reproducible, stable silicon solar cells with high efficiency. A cheap and simple technology should substitute the present one without deterioration of the cell performance. The process here developed has used a spin-on doping, belt furnace instead of a quartz furnace tube, serigraphy instead of photolitography and surface treatment with a special edge protection techniques instead of various unstable methods for pn-transition isolating. The cell area has been enlarged from 5 cm/sup 2/ to 20 cm/sup 2/ and a procedure for p/sup +/nn/sup +/ cells and n/sup +/pp/sup +/ cells is developed. The best textured p/sup +/nn/sup +/ had Jsub(SC) = mA/cm/sup 2/, Vsub(oc) = 603 mV, FF = 0.78, itasub(AM)/sub 1/ = 11.8%. Typical values for n/sup +/pp/sup +/ cells inclusive AR layer was Jsub(SC)= 23.9 mA/cm/sup 2/, Vsub(oc) = 592 mV, FF = 0.77, itasub(AM)/sub 1/ = 11.0%. A solar cell panel with 6 n/sup +/pp/sup +/ cells gave Isub(SC) = 440 mA, Vsub(oc) - 3.5 V. Commercial monocrystalline solar cells are now generally of n/sup +/pp/sup +/ type and have coefficient of performance from 12 to 15% while cell area is varying from 20 to 80 cm/sup 2/.

  8. Influence of Stored Strain on Fabricating of Al/SiC Nanocomposite by Friction Stir Processing

    Science.gov (United States)

    Khorrami, M. Sarkari; Kazeminezhad, M.; Kokabi, A. H.

    2015-05-01

    In this work, 1050 aluminum (Al) sheets were annealed and severely deformed by 1, 2, and 3 passes of constrained groove pressing process to obtain the various initial stored strain values of 0, 1.16, 2.32, and 3.48, respectively. Friction stir processing (FSP) was then applied using SiC nanoparticles to fabricate Al/SiC nanocomposite with approximately 1.5 vol pct reinforced particles. Microstructural examinations revealed that an increase in the initial stored strain of the base metal led to the formation of finer grain structure after 1 pass of FSP. The finer grain structure occurred in the stir zone where a sufficient amount of nanoparticles with a relatively proper distribution existed. However, the initial stored strain value had a contrary influence in the regions with low volume fraction of nanoparticles. In fact, more stored strain in the base metal provided more driving force for both nucleation and grain growth of newly recrystallized grains at the stir zone. Pinning effect of well-distributed nanoparticles could effectively retard grain growth leading to the formation of very fine grain structure. Also it was observed that the initial stored strain values did not have impressive rule in the microstructural evolutions at the stir zone during the second and third FSP passes signifying that all of the stored energy in the base metal would be released after 1 pass of FSP. The results obtained with microhardness measurement at the stir zone were fairly in agreement with those achieved by the microstructure assessments.

  9. Study of the mechanical properties of photo-cured epoxy resin fabricated by stereolithography process

    Directory of Open Access Journals (Sweden)

    Nattapon Chantarapanich

    2013-02-01

    Full Text Available Stereolithography process enables various freeform geometries to be manufactured, which are beneficial to manyresearch and development fields, particularly on medicine. The mechanical properties of stereolithography models can begenerally but not only influenced by the material characteristics, but also by the method of manufacturing. Since thestereolithography process involves building three dimensional objects by depositing material layer-by-layer as well as thepost-curing by ultraviolet light, it is therefore possible for stereolithography models to exhibit a directional dependence of themechanical properties. The objectives of the study focused on the influence of build orientations and ultraviolet post-curingperiod on the mechanical properties. In the experiments, Watershed 11122 commercial epoxy photo-curable resin was used.The in-house developed stereolithography machine of the National Metal and Materials Technology Center of Thailand wasused to fabricate tensile test specimens (American Society for Testing Materials Standard D638 with different build orientations. Main build orientations included flat and edge. Each main build orientation contained three sub-build orientationswhich were 0 degree, 45 degrees, and 90 degrees to the x-axis. The mechanical properties including elastic modulus, ultimatetensile strength, elongation at ultimate tensile strength, and elongation at break were evaluated by tensile test with a universal testing machine. The results indicated that the mechanical properties of specimens were slightly different among thesub-build orientations. The larger differences of mechanical properties of specimens were found between main build orientations. The mechanical strength of specimens improved corresponding to the increase of UV post-curing period ranged from0 to 4 hours whereas the post-curing period using 4 hours onward, the mechanical properties of specimens were nearlyconstant.

  10. Fabricating process of hollow out-of-plane Ni microneedle arrays and properties of the integrated microfluidic device

    Science.gov (United States)

    Zhu, Jun; Cao, Ying; Wang, Hong; Li, Yigui; Chen, Xiang; Chen, Di

    2013-07-01

    Although microfluidic devices that integrate microfluidic chips with hollow out-of-plane microneedle arrays have many advantages in transdermal drug delivery applications, difficulties exist in their fabrication due to the special three-dimensional structures of hollow out-of-plane microneedles. A new, cost-effective process for the fabrication of a hollow out-of-plane Ni microneedle array is presented. The integration of PDMS microchips with the Ni hollow microneedle array and the properties of microfluidic devices are also presented. The integrated microfluidic devices provide a new approach for transdermal drug delivery.

  11. Fabrication and electrochemical properties of insoluble fullerene-diamine adduct thin-films as buffer layer by alternate immersion process

    Science.gov (United States)

    Saito, Jo; Akiyama, Tsuyoshi; Suzuki, Atsushi; Oku, Takeo

    2017-01-01

    Insoluble fullerene-diamine adduct thin-films consisting of C60 and 1,2-diaminoethane were easily fabricated on an electrode by an alternate immersion process. Formation of the C60-diamine adduct films were confirmed using transmission absorption spectroscopy and atomic force microscopy. An inverted-type organic solar cells were fabricated by using the C60-diamine adduct film as the electron transport layer. The resultant photoelectric conversation performance of the solar cells suggested that photocurrent is generated via the photoexcitation of polythiophene. The result suggests that the present insoluble fullerene-diamine adduct films worked as buffer layer for organic thin-film solar cells.

  12. Centre seeded infiltration and growth process for fabrication of large grain bulk YBCO/Ag superconducting composites

    Science.gov (United States)

    Parthasarathy, R.; Seshubai, V.

    2012-06-01

    We report the fabrication of a large grain bulk YBCO/Ag superconductor using a novel technique which we call Centre Seeded Infiltration and Growth Process (CSIGP). Using this technique, it has been made possible to get bulk YBCO/Ag composite sample with uniform grain growth textured along the c-axis. The resulting large grain sample has been found to have high critical current densities up to large magnetic fields. We correlate the improved superconducting and magnetic properties to the modified grain growth conditions employed in this fabrication technique.

  13. A simultaneous process of 3D magnesium phosphate scaffold fabrication and bioactive substance loading for hard tissue regeneration.

    Science.gov (United States)

    Lee, Jongman; Farag, Mohammad Mahmoud; Park, Eui Kyun; Lim, Jiwon; Yun, Hui-Suk

    2014-03-01

    A novel room temperature process was developed to produce a 3D porous magnesium phosphate (MgP) scaffold with high drug load/release efficiency for use in hard tissue regeneration through a combination of a paste extruding deposition (PED) system and cement chemistry. MgP scaffolds were prepared using a two-step process. The first step was fabrication of the 3D porous scaffold green body to control both the morphology and pore structure using a PED system without hardening. The second step was cementation, which was carried out by immersing the scaffold green body in the binder solution for hardening instead of the typical sintering process in ceramic scaffold fabrication. Separation of the manufacturing process and cement reaction was important to secure enough time to fabricate a 3D scaffold with various sizes and architectures under homogeneous extruding conditions. Because the whole process is carried out at room temperature, the bioactive molecules, which are easily denatured by heat, may apply to scaffolds during the process. Lysozyme was selected as a model bioactive substance to demonstrate the efficiency of this process; this was directly mixed into MgP powder to introduce homogeneous distribution in the scaffold. The extruding paste for the PED system was prepared using the MgP-lysozyme blended powder as starting materials. That is, both 3D scaffold fabrication and functionalization of the scaffold with bioactive substances could be carried out simultaneously. This process significantly enhanced both drug loading efficiency and release performance compared to the typical sintering process, where the drug is generally loaded by adsorption after heat treatment. The MgP scaffold developed in this study satisfied the required conditions for scaffolding in hard tissue regeneration in an ideal manner, including 3 dimensionally well-interconnected pore structures, favorable mechanical properties, biodegradability, good cell affinity and in vitro biocompatibility

  14. Virtual fabrication using directed self-assembly for process optimization in a 14-nm dynamic random access memory

    Science.gov (United States)

    Kamon, Mattan; Akbulut, Mustafa; Yan, Yiguang; Faken, Daniel; Pap, Andras; Allampalli, Vasanth; Greiner, Ken; Fried, David

    2016-07-01

    For directed self-assembly (DSA) to be deployed in advanced semiconductor technologies, it must reliably integrate into a full process flow. We present a methodology for using virtual fabrication software, including predictive DSA process models, to develop and analyze the replacement of self-aligned quadruple patterning with Liu-Nealey chemoepitaxy on a 14-nm dynamic random access memory (DRAM) process. To quantify the impact of this module replacement, we investigated a key process yield metric for DRAM, interface area between the capacitor contacts and transistor source/drain. Additionally, we demonstrate virtual fabrication of the DRAM cell's hexagonally packed capacitors patterned with an array of diblock copolymer cylinders in place of fourfold litho-etch (LE4) patterning.

  15. Enhanced Fabrication Processes Development for High Actuator Count Deformable Mirrors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to design and fabricate a MEMS micromirror array consisting of 1021 ultra-flat, close-packed hexagonal mirror elements, each capable of 6mrad of tip and...

  16. Assessment of the infrared welding process for a carbon fabric reinforced pps

    OpenAIRE

    Allaer, Klaas; De Baere, Ives; Jacques, Stefan; Van Paepegem, Wim; Degrieck, Joris

    2012-01-01

    This study assesses the use of infrared welding for a carbon fabric reinforced polyphenylene sulphide. Infrared light is used in order to melt the thermoplastic matrix of the two components, after which they are joined together under pressure. Welding parameters such as power of the infrared lights, heating time, contact pressure and consolidation time are optimised. Next, a series of joints is fabricated and the interlaminar behaviour of the weld is characterised. For the mode I behaviour, t...

  17. Large voltage modulation in superconducting quantum interference devices with submicron-scale step-edge junctions

    Science.gov (United States)

    Lam, Simon K. H.

    2017-09-01

    A promising direction to improve the sensitivity of a SQUID is to increase its junction's normal resistance value, Rn, as the SQUID modulation voltage scales linearly with Rn. As a first step to develop highly sensitive single layer SQUID, submicron scale YBCO grain boundary step edge junctions and SQUIDs with large Rn were fabricated and studied. The step-edge junctions were reduced to submicron scale to increase their Rn values using focus ion beam, FIB and the measurement of transport properties were performed from 4.3 to 77 K. The FIB induced deposition layer proves to be effective to minimize the Ga ion contamination during the FIB milling process. The critical current-normal resistance value of submicron junction at 4.3 K was found to be 1-3 mV, comparable to the value of the same type of junction in micron scale. The submicron junction Rn value is in the range of 35-100 Ω, resulting a large SQUID modulation voltage in a wide temperature range. This performance promotes further investigation of cryogen-free, high field sensitivity SQUID applications at medium low temperature, e.g. at 40-60 K.

  18. Direct fabrication of compound-eye microlens array on curved surfaces by a facile femtosecond laser enhanced wet etching process

    Science.gov (United States)

    Bian, Hao; Wei, Yang; Yang, Qing; Chen, Feng; Zhang, Fan; Du, Guangqing; Yong, Jiale; Hou, Xun

    2016-11-01

    We report a direct fabrication of an omnidirectional negative microlens array on a curved substrate by a femtosecond laser enhanced chemical etching process, which is utilized as a molding template for duplicating bioinspired compound eyes. The femtosecond laser treatment of the curved glass substrate employs a common x-y-z stage without rotating the sample surface perpendicular to the laser beam, and uniform, omnidirectional-aligned negative microlenses are generated after a hydrofluoric acid etching. Using the negative microlens array on the concave glass substrate as a molding template, we fabricate an artificial compound eye with 3000 positive microlenses of 95-μm diameter close-packed on a 5-mm polymer hemisphere. Compared to the transferring process, the negative microlenses directly fabricated on the curved mold by our method are distortion-free, and the duplicated artificial eye presents clear and uniform imaging capabilities. This work provides a facile and efficient route to the fabrication of microlenses on any curved substrates without complicated alignment and motion control processes, which has the potential for the development of new microlens-based devices and systems.

  19. Development and demonstration of manufacturing processes for fabricating graphite/Larc-160 polyimide structural elements, part 4, paragraph B

    Science.gov (United States)

    1981-01-01

    Progress in the development of processes for production of Celion/LARC-160 graphite-polyimide materials, quality control, and the fabrication of Space Shuttle composite structure components is reported. Liquid chromatographic analyses of three repeatibility batches were performed and are compared to previous Hexcel standard production and to variables study LARC-160 intermediate resins. Development of processes for chopped fiber molding are described and flexural strength, elastic modulus, and other physical and mechanical properties of the molding are presented.

  20. Polymer Microfluidics: Simple, Low-Cost Fabrication Process Bridging Academic Lab Research to Commercialized Production

    Directory of Open Access Journals (Sweden)

    Chia-Wen Tsao

    2016-12-01

    Full Text Available Using polymer materials to fabricate microfluidic devices provides simple, cost effective, and disposal advantages for both lab-on-a-chip (LOC devices and micro total analysis systems (μTAS. Polydimethylsiloxane (PDMS elastomer and thermoplastics are the two major polymer materials used in microfluidics. The fabrication of PDMS and thermoplastic microfluidic device can be categorized as front-end polymer microchannel fabrication and post-end microfluidic bonding procedures, respectively. PDMS and thermoplastic materials each have unique advantages and their use is indispensable in polymer microfluidics. Therefore, the proper selection of polymer microfabrication is necessary for the successful application of microfluidics. In this paper, we give a short overview of polymer microfabrication methods for microfluidics and discuss current challenges and future opportunities for research in polymer microfluidics fabrication. We summarize standard approaches, as well as state-of-art polymer microfluidic fabrication methods. Currently, the polymer microfluidic device is at the stage of technology transition from research labs to commercial production. Thus, critical consideration is also required with respect to the commercialization aspects of fabricating polymer microfluidics. This article provides easy-to-understand illustrations and targets to assist the research community in selecting proper polymer microfabrication strategies in microfluidics.

  1. 3D printed electromagnetic transmission and electronic structures fabricated on a single platform using advanced process integration techniques

    Science.gov (United States)

    Deffenbaugh, Paul Issac

    3D printing has garnered immense attention from many fields including in-office rapid prototyping of mechanical parts, outer-space satellite replication, garage functional firearm manufacture, and NASA rocket engine component fabrication. 3D printing allows increased design flexibility in the fabrication of electronics, microwave circuits and wireless antennas and has reached a level of maturity which allows functional parts to be printed. Much more work is necessary in order to perfect the processes of 3D printed electronics especially in the area of automation. Chapter 1 shows several finished prototypes of 3D printed electronics as well as newly developed techniques in fabrication. Little is known about the RF and microwave properties and applications of the standard materials which have been developed for 3D printing. Measurement of a wide variety of materials over a broad spectrum of frequencies up to 10 GHz using a variety of well-established measurement methods is performed throughout chapter 2. Several types of high frequency RF transmission lines are fabricated and valuable model-matched data is gathered and provided in chapter 3 for future designers' use. Of particular note is a fully 3D printed stripline which was automatically fabricated in one process on one machine. Some core advantages of 3D printing RF/microwave components include rapid manufacturing of complex, dimensionally sensitive circuits (such as antennas and filters which are often iteratively tuned) and the ability to create new devices that cannot be made using standard fabrication techniques. Chapter 4 describes an exemplary fully 3D printed curved inverted-F antenna.

  2. CMOS Interface Circuits for Spin Tunneling Junction Based Magnetic Random Access Memories

    Energy Technology Data Exchange (ETDEWEB)

    Ganesh Saripalli

    2002-12-31

    Magneto resistive memories (MRAM) are non-volatile memories which use magnetic instead of electrical structures to store data. These memories, apart from being non-volatile, offer a possibility to achieve densities better than DRAMs and speeds faster than SRAMs. MRAMs could potentially replace all computer memory RAM technologies in use today, leading to future applications like instan-on computers and longer battery life for pervasive devices. Such rapid development was made possible due to the recent discovery of large magnetoresistance in Spin tunneling junction devices. Spin tunneling junctions (STJ) are composite structures consisting of a thin insulating layer sandwiched between two magnetic layers. This thesis research is targeted towards these spin tunneling junction based Magnetic memories. In any memory, some kind of an interface circuit is needed to read the logic states. In this thesis, four such circuits are proposed and designed for Magnetic memories (MRAM). These circuits interface to the Spin tunneling junctions and act as sense amplifiers to read their magnetic states. The physical structure and functional characteristics of these circuits are discussed in this thesis. Mismatch effects on the circuits and proper design techniques are also presented. To demonstrate the functionality of these interface structures, test circuits were designed and fabricated in TSMC 0.35{micro} CMOS process. Also circuits to characterize the process mismatches were fabricated and tested. These results were then used in Matlab programs to aid in design process and to predict interface circuit's yields.

  3. CMOS Interface Circuits for Spin Tunneling Junction Based Magnetic Random Access Memories

    Energy Technology Data Exchange (ETDEWEB)

    Saripalli, Ganesh [Iowa State Univ., Ames, IA (United States)

    2002-01-01

    Magneto resistive memories (MRAM) are non-volatile memories which use magnetic instead of electrical structures to store data. These memories, apart from being non-volatile, offer a possibility to achieve densities better than DRAMs and speeds faster than SRAMs. MRAMs could potentially replace all computer memory RAM technologies in use today, leading to future applications like instan-on computers and longer battery life for pervasive devices. Such rapid development was made possible due to the recent discovery of large magnetoresistance in Spin tunneling junction devices. Spin tunneling junctions (STJ) are composite structures consisting of a thin insulating layer sandwiched between two magnetic layers. This thesis research is targeted towards these spin tunneling junction based Magnetic memories. In any memory, some kind of an interface circuit is needed to read the logic states. In this thesis, four such circuits are proposed and designed for Magnetic memories (MRAM). These circuits interface to the Spin tunneling junctions and act as sense amplifiers to read their magnetic states. The physical structure and functional characteristics of these circuits are discussed in this thesis. Mismatch effects on the circuits and proper design techniques are also presented. To demonstrate the functionality of these interface structures, test circuits were designed and fabricated in TSMC 0.35μ CMOS process. Also circuits to characterize the process mismatches were fabricated and tested. These results were then used in Matlab programs to aid in design process and to predict interface circuit's yields.

  4. Junction like behavior in polycrystalline diamond films

    Energy Technology Data Exchange (ETDEWEB)

    Bhaskaran, Shivakumar, E-mail: sbhaskar@mail.uh.edu [Department of Electrical and Computer Engineering, Cullen College of Engineering, University of Houston, TX 77004 (United States); Charlson, Earl Joe; Litvinov, Dmitri [Department of Electrical and Computer Engineering, Cullen College of Engineering, University of Houston, TX 77004 (United States); Makarenko, Boris [Department of Chemistry, University of Houston, TX 77004 (United States)

    2012-01-25

    Highlights: Black-Right-Pointing-Pointer The result that we obtained are compared with single crystalline diamond devices. Black-Right-Pointing-Pointer The barrier height of 4.4 eV matches the ideal pn-junction barrier height of diamond thin film. - Abstract: We have successfully fabricated polycrystalline diamond rectifying junction devices on n-type (1 0 0) silicon substrates by Hot Filament Chemical Vapor Deposition (HFCVD) using methane/hydrogen process gas and trimethyl borate and trimethyl phosphite dissolved in acetone as p- and n-type dopants, respectively. Impedance spectroscopy and current-voltage analysis indicates that the conduction is vertical down the grains and facets and not due to surface effects. Electrical characteristics were analyzed with In and Ti/Au top metal contacts with Al as the substrate contact. Current-voltage characteristics as a function of temperature showed barrier potentials of 1.1 eV and 0.77 eV for the In and Ti/Au contacts, respectively. Barrier heights of 4.8 eV (In) and 4.4 eV (Ti/Au) were obtained from capacitance-voltage measurements.

  5. Annealing free magnetic tunnel junction sensors

    Science.gov (United States)

    Knudde, S.; Leitao, D. C.; Cardoso, S.; Freitas, P. P.

    2017-04-01

    Annealing is a major step in the fabrication of magnetic tunnel junctions (MTJs). It sets the exchange bias between the pinned and antiferromagnetic layers, and helps to increase the tunnel magnetoresistance (TMR) in both amorphous and crystalline junctions. Recent research on MTJs has focused on MgO-based structures due to their high TMR. However, the strict process control and mandatory annealing step can limit the scope of the application of these structures as sensors. In this paper, we present AlOx-based MTJs that are produced by ion beam sputtering and remote plasma oxidation and show optimum transport properties with no annealing. The microfabricated devices show TMR values of up to 35% and using NiFe/CoFeB free layers provides tunable linear ranges, leading to coercivity-free linear responses with sensitivities of up to 5.5%/mT. The top-pinned synthetic antiferromagnetic reference shows a stability of about 30 mT in the microfabricated devices. Sensors with linear ranges of up to 60 mT are demonstrated. This paves the way for the integration of MTJ sensors in heat-sensitive applications such as flexible substrates, or for the design of low-footprint on-chip multiaxial sensing devices.

  6. Characterization of a fabrication process for the integration of superconducting qubits and rapid-single-flux-quantum circuits

    Science.gov (United States)

    Castellano, Maria Gabriella; Grönberg, Leif; Carelli, Pasquale; Chiarello, Fabio; Cosmelli, Carlo; Leoni, Roberto; Poletto, Stefano; Torrioli, Guido; Hassel, Juha; Helistö, Panu

    2006-08-01

    In order to integrate superconducting qubits with rapid-single-flux-quantum (RSFQ) control circuitry, it is necessary to develop a fabrication process that simultaneously fulfils the requirements of both elements: low critical current density, very low operating temperature (tens of millikelvin) and reduced dissipation on the qubit side; high operation frequency, large stability margins, low dissipated power on the RSFQ side. For this purpose, VTT has developed a fabrication process based on Nb trilayer technology, which allows the on-chip integration of superconducting qubits and RSFQ circuits even at very low temperature. Here we present the characterization (at 4.2 K) of the process from the point of view of the Josephson devices and show that they are suitable to build integrated superconducting qubits.

  7. A three-mask process for fabricating vacuum-sealed capacitive micromachined ultrasonic transducers using anodic bonding.

    Science.gov (United States)

    Yamaner, F Yalçın; Zhang, Xiao; Oralkan, Ömer

    2015-05-01

    This paper introduces a simplified fabrication method for vacuum-sealed capacitive micromachined ultrasonic transducer (CMUT) arrays using anodic bonding. Anodic bonding provides the established advantages of wafer-bondingbased CMUT fabrication processes, including process simplicity, control over plate thickness and properties, high fill factor, and ability to implement large vibrating cells. In addition to these, compared with fusion bonding, anodic bonding can be performed at lower processing temperatures, i.e., 350°C as opposed to 1100°C; surface roughness requirement for anodic bonding is more than 10 times more relaxed, i.e., 5-nm rootmean- square (RMS) roughness as opposed to 0.5 nm for fusion bonding; anodic bonding can be performed on smaller contact area and hence improves the fill factor for CMUTs. Although anodic bonding has been previously used for CMUT fabrication, a CMUT with a vacuum cavity could not have been achieved, mainly because gas is trapped inside the cavities during anodic bonding. In the approach we present in this paper, the vacuum cavity is achieved by opening a channel in the plate structure to evacuate the trapped gas and subsequently sealing this channel by conformal silicon nitride deposition in the vacuum environment. The plate structure of the fabricated CMUT consists of the single-crystal silicon device layer of a silicon-on-insulator wafer and a thin silicon nitride insulation layer. The presented fabrication approach employs only three photolithographic steps and combines the advantages of anodic bonding with the advantages of a patterned metal bottom electrode on an insulating substrate, specifically low parasitic series resistance and low parasitic shunt capacitance. In this paper, the developed fabrication scheme is described in detail, including process recipes. The fabricated transducers are characterized using electrical input impedance measurements in air and hydrophone measurements in immersion. A representative

  8. Step edge Josephson junctions and high temperature superconducting quantum interference device (SQUID) gradiometers

    CERN Document Server

    Millar, A J

    2002-01-01

    This thesis is concerned with the development of Superconducting Quantum Interference Device (SQUID) gradiometers based on the high temperature superconductor YBa sub 2 Cu sub 3 O sub 7 sub - subdelta (YBCO). A step-edge Josephson junction fabrication process was developed to produce sufficiently steep (>60 deg) step-edges such that junctions exhibited RSJ-like current-voltage characteristics. The mean I sub C R sub N product of a sample of twenty step-edge junctions was 130 mu V. Step-edge dc SQUIDs with inductances between 67pH and 114pH were fabricated. Generally the SQUIDs had an intrinsic white flux noise in the 10-30 mu PHI sub 0 /sq root Hz range, with the best device, a 70pH SQUID, exhibiting a white flux noise of 5 mu PHI sub 0 /sq root Hz. Different first-order SQUID gradiometer designs were fabricated from single layers of YBCO. Two single-layer gradiometer (SLG) designs were fabricated on 10x10mm sup 2 substrates. The best balance and lowest gradient sensitivity measured for these devices were 1/3...

  9. Design, simulation and fabrication of a MEMS accelerometer by using sequential and pulsed-mode DRIE processes

    Science.gov (United States)

    Gholamzadeh, R.; Jafari, K.; Gharooni, M.

    2017-01-01

    A sensitive half-bridge MEMS accelerometer fabricated by sequential and pulsed-mode processes is presented in this paper. The proposed accelerometer is analyzed by using conventional equations and the finite element method. The micromachining technology used in this work relies on two processes: sequential and pulsed-mode. In the sequential deep reactive ion etching process, a mixture of hydrogen and oxygen with a trace value of SF6 is used instead of polymeric material in the passivation step. The pulsed-mode process employs periodic hydrogen pulses in continuous fluorine plasma. Because of the continuous nature of this process, plus the in situ passivation caused by the hydrogen pulses, scallop-free sidewalls are achieved and the etch rate is also relatively high. Furthermore, the functional characteristics of the fabricated accelerometer sensor are measured and reported. Measurement results, which are in good agreement with simulations, show that the functional characteristics of the fabricated sensor are as follows: resonance frequency of about 2 kHz, sensitivity of 76 mV g-1 and Brownian noise equivalent acceleration of 4.74~μ g {{\\sqrt{\\text{Hz}}}-1} .

  10. Modified Powder-in-Tube Technique Based on the Consolidation Processing of Powder Materials for Fabricating Specialty Optical Fibers

    Directory of Open Access Journals (Sweden)

    Jean-Louis Auguste

    2014-08-01

    Full Text Available The objective of this paper is to demonstrate the interest of a consolidation process associated with the powder-in-tube technique in order to fabricate a long length of specialty optical fibers. This so-called Modified Powder-in-Tube (MPIT process is very flexible and paves the way to multimaterial optical fiber fabrications with different core and cladding glassy materials. Another feature of this technique lies in the sintering of the preform under reducing or oxidizing atmosphere. The fabrication of such optical fibers implies different constraints that we have to deal with, namely chemical species diffusion or mechanical stress due to the mismatches between thermal expansion coefficients and working temperatures of the fiber materials. This paper focuses on preliminary results obtained with a lanthano-aluminosilicate glass used as the core material for the fabrication of all-glass fibers or specialty Photonic Crystal Fibers (PCFs. To complete the panel of original microstructures now available by the MPIT technique, we also present several optical fibers in which metallic particles or microwires are included into a silica-based matrix.

  11. High-Performance Flexible Transparent Electrode with an Embedded Metal Mesh Fabricated by Cost-Effective Solution Process.

    Science.gov (United States)

    Khan, Arshad; Lee, Sangeon; Jang, Taehee; Xiong, Ze; Zhang, Cuiping; Tang, Jinyao; Guo, L Jay; Li, Wen-Di

    2016-06-01

    A new structure of flexible transparent electrodes is reported, featuring a metal mesh fully embedded and mechanically anchored in a flexible substrate, and a cost-effective solution-based fabrication strategy for this new transparent electrode. The embedded nature of the metal-mesh electrodes provides a series of advantages, including surface smoothness that is crucial for device fabrication, mechanical stability under high bending stress, strong adhesion to the substrate with excellent flexibility, and favorable resistance against moisture, oxygen, and chemicals. The novel fabrication process replaces vacuum-based metal deposition with an electrodeposition process and is potentially suitable for high-throughput, large-volume, and low-cost production. In particular, this strategy enables fabrication of a high-aspect-ratio (thickness to linewidth) metal mesh, substantially improving conductivity without considerably sacrificing transparency. Various prototype flexible transparent electrodes are demonstrated with transmittance higher than 90% and sheet resistance below 1 ohm sq(-1) , as well as extremely high figures of merit up to 1.5 × 10(4) , which are among the highest reported values in recent studies. Finally using our embedded metal-mesh electrode, a flexible transparent thin-film heater is demonstrated with a low power density requirement, rapid response time, and a low operating voltage.

  12. Improved electrical properties of n-n and p-n Si/SiC junctions with thermal annealing treatment

    Science.gov (United States)

    Liang, J.; Nishida, S.; Arai, M.; Shigekawa, N.

    2016-07-01

    The effects of annealing process on the electrical properties of n+-Si/n-SiC and p+-Si/n-SiC junctions fabricated by using surface-activated bonding are investigated. It is found by measuring the current-voltage (I-V) characteristics of n+-Si/n-SiC junctions that the reverse-bias current and the ideality factor decreased to 2.0 × 10-5 mA/cm2 and 1.10, respectively, after the junctions annealing at 700 °C. The flat band voltages of n+-Si/n-SiC and p+-Si/n-SiC junctions obtained from capacitance-voltage (C-V) measurements decreased with increasing annealing temperature. Furthermore, their flat band voltages are very close to each other irrespective of the annealing temperature change, which suggests that the Fermi level is still pinned at the bonding interface even for the junctions annealing at high temperature and the interface state density causing Fermi level pinning varies with the junctions annealing. The reverse characteristics of n+-Si/n-SiC junctions are in good agreement with the calculations based on thermionic field emission. In addition, the calculated donor concentration of 4H-SiC epi-layers and flat band voltage is consistent with the values obtained from C-V measurements.

  13. Adiabatic quantum-flux-parametron cell library designed using a 10 kA cm-2 niobium fabrication process

    Science.gov (United States)

    Takeuchi, Naoki; Nagasawa, Shuichi; China, Fumihiro; Ando, Takumi; Hidaka, Mutsuo; Yamanashi, Yuki; Yoshikawa, Nobuyuki

    2017-03-01

    Adiabatic quantum-flux-parametron (AQFP) logic is an energy-efficient superconductor logic with zero static power consumption and very small switching energy. In this paper, we report a new AQFP cell library designed using the AIST 10 kA cm-2 Nb high-speed standard process (HSTP), which is a high-critical-current-density version of the AIST 2.5 kA cm-2 Nb standard process (STP2). Since the intrinsic damping of the Josephson junction (JJ) of HSTP is relatively strong, shunt resistors for JJs were removed and the energy efficiency improved significantly. Also, excitation transformers in the new cells were redesigned so that the cells can operate in a four-phase excitation mode. We described the detail of HSTP and the AQFP cell library designed using HSTP, and showed experimental results of cell test circuits.

  14. NbN/MgO/NbN edge-geometry tunnel junctions

    Science.gov (United States)

    Hunt, B. D.; Leduc, H. G.; Cypher, S. R.; Stern, J. A.; Judas, A.

    1989-01-01

    The fabrication and low-frequency testing of the first edge-geometry NbN/MgO/NbN superconducting tunnel junctions are reported. The use of an edge geometry allows very small junction areas to be obtained, while the all-NbN electrodes permit operation at 8-10 K with a potential maximum operating frequency above 1 THz. Edge definition in the base NbN film was accomplished utilizing Ar ion milling with an Al2O3 milling mask, followed by a lower energy ion cleaning step. This process has produced all-refractory-material tunnel junctions with areas as small as 0.1 sq micron, resistance-area products less than 21 ohm sq micron, and subgap to normal state resistance ratios larger than 18.

  15. An array microscope for ultrarapid virtual slide processing and telepathology. Design, fabrication, and validation study.

    Science.gov (United States)

    Weinstein, Ronald S; Descour, Michael R; Liang, Chen; Barker, Gail; Scott, Katherine M; Richter, Lynne; Krupinski, Elizabeth A; Bhattacharyya, Achyut K; Davis, John R; Graham, Anna R; Rennels, Margaret; Russum, William C; Goodall, James F; Zhou, Pixuan; Olszak, Artur G; Williams, Bruce H; Wyant, James C; Bartels, Peter H

    2004-11-01

    This paper describes the design and fabrication of a novel array microscope for the first ultrarapid virtual slide processor (DMetrix DX-40 digital slide scanner). The array microscope optics consists of a stack of three 80-element 10 x 8-lenslet arrays, constituting a "lenslet array ensemble." The lenslet array ensemble is positioned over a glass slide. Uniquely shaped lenses in each of the lenslet arrays, arranged perpendicular to the glass slide constitute a single "miniaturized microscope." A high-pixel-density image sensor is attached to the top of the lenslet array ensemble. In operation, the lenslet array ensemble is transported by a motorized mechanism relative to the long axis of a glass slide. Each of the 80 miniaturized microscopes has a lateral field of view of 250 microns. The microscopes of each row of the array are offset from the microscopes in other rows. Scanning a glass slide with the array microscope produces seamless two-dimensional image data of the entire slide, that is, a virtual slide. The optical system has a numerical aperture of N.A.= 0.65, scans slides at a rate of 3 mm per second, and accrues up to 3,000 images per second from each of the 80 miniaturized microscopes. In the ultrarapid virtual slide processing cycle, the time for image acquisition takes 58 seconds for a 2.25 cm2 tissue section. An automatic slide loader enables the scanner to process up to 40 slides per hour without operator intervention. Slide scanning and image processing are done concurrently so that post-scan processing is eliminated. A virtual slide can be viewed over the Internet immediately after the scanning is complete. A validation study compared the diagnostic accuracy of pathologist case readers using array microscopy (with images viewed as virtual slides) and conventional light microscopy. Four senior pathologists diagnosed 30 breast surgical pathology cases each using both imaging modes, but on separate occasions. Of 120 case reads by array microscopy

  16. Retention of denture bases fabricated by three different processing techniques – An in vivo study

    Science.gov (United States)

    Chalapathi Kumar, V. H.; Surapaneni, Hemchand; Ravikiran, V.; Chandra, B. Sarat; Balusu, Srilatha; Reddy, V. Naveen

    2016-01-01

    Aim: Distortion due to Polymerization shrinkage compromises the retention. To evaluate the amount of retention of denture bases fabricated by conventional, anchorized, and injection molding polymerization techniques. Materials and Methods: Ten completely edentulous patients were selected, impressions were made, and master cast obtained was duplicated to fabricate denture bases by three polymerization techniques. Loop was attached to the finished denture bases to estimate the force required to dislodge them by retention apparatus. Readings were subjected to nonparametric Friedman two-way analysis of variance followed by Bonferroni correction methods and Wilcoxon matched-pairs signed-ranks test. Results: Denture bases fabricated by injection molding (3740 g), anchorized techniques (2913 g) recorded greater retention values than conventional technique (2468 g). Significant difference was seen between these techniques. Conclusions: Denture bases obtained by injection molding polymerization technique exhibited maximum retention, followed by anchorized technique, and least retention was seen in conventional molding technique. PMID:27382542

  17. Fabrication of sub-12 nm thick silicon nanowires by processing scanning probe lithography masks

    Energy Technology Data Exchange (ETDEWEB)

    Kyoung Ryu, Yu; Garcia, Ricardo, E-mail: r.garcia@csic.es [Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juana Inés de la Cruz 3, 28049 Madrid (Spain); Aitor Postigo, Pablo; Garcia, Fernando [Instituto de Microelectrónica de Madrid (IMM-CNM-CSIC), 28760 Tres Cantos, Madrid (Spain)

    2014-06-02

    Silicon nanowires are key elements to fabricate very sensitive mechanical and electronic devices. We provide a method to fabricate sub-12 nm silicon nanowires in thickness by combining oxidation scanning probe lithography and anisotropic dry etching. Extremely thin oxide masks (0.3–1.1 nm) are transferred into nanowires of 2–12 nm in thickness. The width ratio between the mask and the silicon nanowire is close to one which implies that the nanowire width is controlled by the feature size of the nanolithography. This method enables the fabrication of very small single silicon nanowires with cross-sections below 100 nm{sup 2}. Those values are the smallest obtained with a top-down lithography method.

  18. An important impact of the molecule-electrode couplings asymmetry on the efficiency of bias-driven redox processes in molecular junctions

    CERN Document Server

    Baldea, Ioan

    2015-01-01

    Two recent experimental (Li, J.~\\emphj{et al}, \\emph{Proc.\\ Natl.\\ Acad.\\ Sci.\\ U.~S.~A.} {\\bf 2014}, 111, 1282-1287) and theoretical studies (B\\^aldea, I, \\emph{Phys.\\ Chem.\\ Chem.\\ Phys.}\\ {\\bf 2014}, 16, 25942-25949) have addressed the problem of tuning molecular charge and vibrational properties of single molecules embedded in nanojunctions. These are molecular characteristics escaping so far to an efficient experimental control in broad ranges. Here, we present a general argument demonstrating why, out of various experimental platforms possible, those wherein active molecules are asymmetrically coupled to electrodes are to be preferred to those symmetrically coupled for achieving a(n almost) complete redox process, and why electrochemical environment has advantages over "dry" setups. This study aims at helping to nanofabricate molecular junctions using the most appropriate platforms enabling the broadest possible bias-driven control of the redox state and vibrational modes of single molecules linked to e...

  19. First-principles study on bottom-up fabrication process of atomically precise graphene nanoribbons

    Science.gov (United States)

    Kaneko, Tomoaki; Tajima, Nobuo; Ohno, Takahisa

    2016-06-01

    We investigate the energetics of a polyanthracene formation in the bottom-up fabrication of atomically precise graphene nanoribbons on Au(111) using first-principles calculations based on the density functional theory. We show that the structure of precursor molecules plays a decisive role in the C-C coupling reaction. The reaction energy of the dimerization of anthracene dimers is a larger negative value than that of the dimerization of anthracene monomers, suggesting that the precursor molecule used in experiments has a favorable structure for graphene nanoribbon fabrication.

  20. A simple method for fabricating p–n junction photocatalyst CuFe{sub 2}O{sub 4}/Bi{sub 4}Ti{sub 3}O{sub 12} and its photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, W.; Jin, Y.; Gao, C.H.; Gu, W.; Jin, Z.M. [Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou 215123 (China); Lei, Y.L. [Center of Super-Diamond and Advanced Films (COSDAF) and Department of Physics and Materials Science, City University of Hong Kong, Hong Kong (China); Liao, L.S., E-mail: lsliao@suda.edu.cn [Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou 215123 (China)

    2014-02-14

    The synthesis of Bi{sub 4}Ti{sub 3}O{sub 12} and CuFe{sub 2}O{sub 4} powders was achieved using a conventional solid-state reaction and the Sol–Gel method, respectively. A novel p–n heterojunction photocatalyst CuFe{sub 2}O{sub 4}/Bi{sub 4}Ti{sub 3}O{sub 12} was subsequently prepared through ball milling. The structures, morphologies, and optical properties of the photocatalysts were comprehensively characterized. The transmission electron microscopy (TEM) images showed a clear interface between CuFe{sub 2}O{sub 4} and Bi{sub 4}Ti{sub 3}O{sub 12}, indicating that a heterojunction between CuFe{sub 2}O{sub 4} and Bi{sub 4}Ti{sub 3}O{sub 12} was formed during ball milling. In addition, the photocatalytic activity was evaluated based on the photocatalytic degradation of methyl orange (MO). The results indicated that the photocatalytic activity of the p–n heterojunction photocatalyst CuFe{sub 2}O{sub 4}/Bi{sub 4}Ti{sub 3}O{sub 12} was higher than that of Bi{sub 4}Ti{sub 3}O{sub 12} alone. The enhanced photocatalytic activity could be attributed to the formation of a heterojunction between CuFe{sub 2}O{sub 4} and Bi{sub 4}Ti{sub 3}O{sub 12}, which suppressed the recombination of photogenerated electron–hole pairs. We also investigated the effects of procedure time and dispersant (H{sub 2}O) during ball milling on the photocatalytic activity. The mechanisms underlying the observed photocatalytic activity were also described based on the semiconductor energy band theory and p–n junction principle. Moreover, the analysis of the radical scavengers confirmed that • O{sub 2}{sup −} and h{sup +} were the primary reactive species to cause the degradation of the MO. - Highlights: • A p–n heterojunction photocatalyst CuFe{sub 2}O{sub 4}/Bi{sub 4}Ti{sub 3}O{sub 12} was prepared by ball milling. • Water is added during the wet milling process to make the powders milled efficiently and dispersed highly. • The photocatalytical mechanism is discussed according to

  1. Fabrication of high-resolution reflective scale grating for an optical encoder using a patterned self-assembly process

    Science.gov (United States)

    Fan, Shanjin; Jiang, Weitao; Li, Xuan; Yu, Haoyu; Lei, Biao; Shi, Yongsheng; Yin, Lei; Chen, Bangdao; Liu, Hongzhong

    2016-07-01

    Steel tape scale grating of a reflective incremental linear encoder has a key impact on the measurement accuracy of the optical encoder. However, it is difficult for conventional manufacturing processes to fabricate scale grating with high-resolution grating strips, due to process and material problems. In this paper, self-assembly technology was employed to fabricate high-resolution steel tape scale grating for a reflective incremental linear encoder. Graphene oxide nanoparticles were adopted to form anti-reflective grating strips of steel tape scale grating. They were deposited in the tape, which had a hydrophobic and hydrophilic grating pattern when the dispersion of the nanoparticles evaporated. A standard lift-off process was employed to fabricate the hydrophobic grating strips on the steel tape. Simultaneously, the steel tape itself presents a hydrophilic property. The hydrophobic and hydrophilic grating pattern was thus obtained. In this study, octafluorocyclobutane was used to prepare the hydrophobic grating strips, due to its hydrophobic property. High-resolution graphene oxide steel tape scale grating with a pitch of 20 μm was obtained through the self-assembly process. The photoelectric signals of the optical encoder containing the graphene oxide scale grating and conventional scale grating were tested under the same conditions. Comparison test results showed that the graphene oxide scale grating has a better performance in its amplitude and harmonic components than that of the conventional steel tape scale. A comparison experiment of position errors was also conducted, demonstrating an improvement in the positioning error of the graphene oxide scale grating. The comparison results demonstrated the applicability of the proposed self-assembly process to fabricate high-resolution graphene oxide scale grating for a reflective incremental linear encoder.

  2. Examining the Roles of Emulsion Droplet Size and Surfactant in the Interfacial Instability-Based Fabrication Process of Micellar Nanocrystals

    Science.gov (United States)

    Sun, Yuxiang; Mei, Ling; Han, Ning; Ding, Xinyi; Yu, Caihao; Yang, Wenjuan; Ruan, Gang

    2017-06-01

    The interfacial instability process is an emerging general method to fabricate nanocrystal-encapsulated micelles (also called micellar nanocrystals) for biological detection, imaging, and therapy. The present work utilized fluorescent semiconductor nanocrystals (quantum dots or QDs) as the model nanocrystals to investigate the interfacial instability-based fabrication process of nanocrystal-encapsulated micelles. Our experimental results suggest intricate and intertwined roles of the emulsion droplet size and the surfactant poly (vinyl alcohol) (PVA) used in the fabrication process of QD-encapsulated poly (styrene-b-ethylene glycol) (PS-PEG) micelles. When no PVA is used, no emulsion droplet and thus no micelle is successfully formed; Emulsion droplets with large sizes ( 25 μm) result in two types of QD-encapsulated micelles, one of which is colloidally stable QD-encapsulated PS-PEG micelles while the other of which is colloidally unstable QD-encapsulated PVA micelles; In contrast, emulsion droplets with small sizes ( 3 μm or smaller) result in only colloidally stable QD-encapsulated PS-PEG micelles. The results obtained in this work not only help to optimize the quality of nanocrystal-encapsulated micelles prepared by the interfacial instability method for biological applications but also offer helpful new knowledge on the interfacial instability process in particular and self-assembly in general.

  3. Process Modelling of Rapid Manufacturing Based Mass Customisation System for Fabrication of Custom Foot Orthoses: Review Paper

    Directory of Open Access Journals (Sweden)

    Saleh Jumani

    2013-04-01

    Full Text Available The need for custom-made devices, rehabilitation aids and treatments is explicit in the medical sector. Applications of rapid manufacturing techniques based on additive fabrication processes combined with medical digitising technologies can generate high quality solutions in situations where the need for custom-made devices and rehabilitation aids and low-lead times are very important factors. Foot orthoses are medical devices applied in the treatment of biomechanical foot disorders, foot injuries and foot diseases including rheumatoid arthritis and diabetes. The significant challenge in the treatment of foot related diseases is progressing pathological deterioration in the affected sites of the foot which requires quick provision of the orthoses. A process model is developed using the IDEF0 modelling technique in which a rapid manufacturing approach is integrated in the design and fabrication process of custom foot orthoses. The process model will be used in the development of rapid manufacturing based design and fabrication system for mass customisation of foot orthoses. The developed system is aimed at mass scale production of custom foot orthoses with the advantages of reduced cost, reduced lead-time and improved product in terms of increased fit, consistency and accuracy in the final product.

  4. Fabrication of High Contrast Gratings for the Spectrum Splitting Dispersive Element in a Concentrated Photovoltaic System.

    Science.gov (United States)

    Yao, Yuhan; Liu, He; Wu, Wei

    2015-07-18

    High contrast gratings are designed and fabricated and its application is proposed in a parallel spectrum splitting dispersive element that can improve the solar conversion efficiency of a concentrated photovoltaic system. The proposed system will also lower the solar cell cost in the concentrated photovoltaic system by replacing the expensive tandem solar cells with the cost-effective single junction solar cells. The structures and the parameters of high contrast gratings for the dispersive elements were numerically optimized. The large-area fabrication of high contrast gratings was experimentally demonstrated using nanoimprint lithography and dry etching. The quality of grating material and the performance of the fabricated device were both experimentally characterized. By analyzing the measurement results, the possible side effects from the fabrication processes are discussed and several methods that have the potential to improve the fabrication processes are proposed, which can help to increase the optical efficiency of the fabricated devices.

  5. Direct Laser Fabrication process with coaxial powder projection of 316L steel. Geometrical characteristics and microstructure characterization of wall structures

    Science.gov (United States)

    El Cheikh, Hussam; Courant, Bruno; Branchu, Samuel; Huang, Xiaowei; Hascoët, Jean-Yves; Guillén, Ronald

    2012-12-01

    Direct Laser Fabrication is a promising manufacturing technology. A moving laser beam heats a coaxially delivered powder in a gas jet through nozzle in order to fabricate an end-use part directly. The clad geometry is an important process characteristic. In this work, different velocities and different laser shift-distances between two successive layers are used to build walls. For each condition, 1, 3, 5 and 10 layers walls are analyzed, showing the domain of a success and optimal construction. A relationship between the process parameters and the wall height is obtained with a good correlation. In addition a linear relationship relates the wall height to the number of layers. Columnar dendrites are observed on the bottom laser clad and equiaxed grains on the top one. Microhardness measurements show a homogeneous microhardness in each layer but a higher microhardness in the first one.

  6. Processing and Electromagnetic Shielding Properties of Multifunctional Metal Composite Knitted Fabric used as Socks

    Directory of Open Access Journals (Sweden)

    Yu Zhicai

    2016-01-01

    Full Text Available In this research, a type of bamboo charcoal polyester (BC-PET/antibacterial nylon(AN/stainless steel wire (SSW metal composite yarn was prepared with a hollow spindle spinning machine, which using the SSW as the core material, the BC-PET and AN as the outer and inner wrapped yarns, respectively. The wrapping numbers was set at 8.0turns/cm for the produced metal composite yarns. Furthermore, a type of plated knitted fabric was designed and produced by using the automatic jacquard knitting machine. The plated knitted fabric presents the BC-PET/AN/SSW metal composite yarn on the knitted fabric face and the crisscross-section polyester (CSP on the knit back. The effect of lamination numbers and angles on the electromagnetic shielding effectiveness (EMSE were discussed in this study. EMSE measurement showed that the lamination angles will influence the EMSE, but not affect the air permeability. Finally, a novel EM shielding socks was designed with the produced plated knitted fabric. Finally, the performance of thermal resistance and evaporation resistance was also test usingThe sweating guarded hot plate apparatus.

  7. Design, fabrication and testing of a wet oxidation waste processing system. [for manned space flight

    Science.gov (United States)

    1975-01-01

    The wet oxidation of sewage sludge during space flight was studied for water and gas recovery, and the elimination of overboard venting. The components of the system are described. Slurry and oxygen supply modules were fabricated and tested. Recommendations for redesign of the equipment are included.

  8. Seebeck effect in molecular junctions

    Science.gov (United States)

    Zimbovskaya, Natalya A.

    2016-05-01

    Advances in the fabrication and characterization of nanoscale systems presently allow for a better understanding of their thermoelectric properties. As is known, the building blocks of thermoelectricity are the Peltier and Seebeck effects. In the present work we review results of theoretical studies of the Seebeck effect in single-molecule junctions and similar systems. The behavior of thermovoltage and thermopower in these systems is controlled by several factors including the geometry of molecular bridges, the characteristics of contacts between the bridge and the electrodes, the strength of the Coulomb interactions between electrons on the bridge, and of electron-phonon interactions. We describe the impact of these factors on the thermopower. Also, we discuss a nonlinear Seebeck effect in molecular junctions.

  9. Fabrication of CoZn alloy nanowire arrays: Significant improvement in magnetic properties by annealing process

    Energy Technology Data Exchange (ETDEWEB)

    Koohbor, M. [Department of Physics, University of Kurdistan, Sanandaj (Iran, Islamic Republic of); Soltanian, S., E-mail: s.soltanian@gmail.com [Department of Physics, University of Kurdistan, Sanandaj (Iran, Islamic Republic of); Department of Electrical and Computer Engineering, University of British Columbia, Vancouver (Canada); Najafi, M. [Department of Physics, University of Kurdistan, Sanandaj (Iran, Islamic Republic of); Department of Physics, Hamadan University of Technology, Hamadan (Iran, Islamic Republic of); Servati, P. [Department of Electrical and Computer Engineering, University of British Columbia, Vancouver (Canada)

    2012-01-05

    Highlights: Black-Right-Pointing-Pointer Increasing the Zn concentration changes the structure of NWs from hcp to amorphous. Black-Right-Pointing-Pointer Increasing the Zn concentration significantly reduces the Hc value of NWs. Black-Right-Pointing-Pointer Magnetic properties of CoZn NWs can be significantly enhanced by appropriate annealing. Black-Right-Pointing-Pointer The pH of electrolyte has no significant effect on the properties of the NW arrays. Black-Right-Pointing-Pointer Deposition frequency has considerable effects on the magnetic properties of NWs. - Abstract: Highly ordered arrays of Co{sub 1-x}Zn{sub x} (0 {<=} x {<=} 0.74) nanowires (NWs) with diameters of {approx}35 nm and high length-to-diameter ratios (up to 150) were fabricated by co-electrodeposition of Co and Zn into pores of anodized aluminum oxide (AAO) templates. The Co and Zn contents of the NWs were adjusted by varying the ratio of Zn and Co ion concentrations in the electrolyte. The effect of the Zn content, electrodeposition conditions (frequency and pH) and annealing on the structural and magnetic properties (e.g., coercivity (Hc) and squareness (Sq)) of NW arrays were investigated using X-ray diffraction (XRD), scanning electron microscopy, electron diffraction, and alternating gradient force magnetometer (AGFM). XRD patterns reveal that an increase in the concentration of Zn ions of the electrolyte forces the hcp crystal structure of Co NWs to change into an amorphous phase, resulting in a significant reduction in Hc. It was found that the magnetic properties of NWs can be significantly improved by appropriate annealing process. The highest values for Hc (2050 Oe) and Sq (0.98) were obtained for NWs electrodeposited using 0.95/0.05 Co:Zn concentrations at 200 Hz and annealed at 575 Degree-Sign C. While the pH of electrolyte is found to have no significant effect on the structural and magnetic properties of the NW arrays, the electrodeposition frequency has considerable effects on

  10. Direct-write PVDF nonwoven fiber fabric energy harvesters via the hollow cylindrical near-field electrospinning process

    Science.gov (United States)

    Liu, Z. H.; Pan, C. T.; Lin, L. W.; Huang, J. C.; Ou, Z. Y.

    2014-02-01

    One-dimensional piezoelectric nanomaterials have attracted great attention in recent years for their possible applications in mechanical energy scavenging devices. However, it is difficult to control the structural diameter, length, and density of these fibers fabricated by micro/nano-technologies. This work presents a hollow cylindrical near-field electrospinning (HCNFES) process to address production and performance issues encountered previously in either far-field electrospinning (FFES) or near-field electrospinning (NFES) processes. Oriented polyvinylidene fluoride (PVDF) fibers in the form of nonwoven fabric have been directly written on a glass tube for aligned piezoelectricity. Under a high in situ electrical poling field and strong mechanical stretching (the tangential speed on the glass tube collector is about 1989.3 mm s-1), the HCNFES process is able to uniformly deposit large arrays of PVDF fibers with good concentrations of piezoelectric β-phase. The nonwoven fiber fabric (NFF) is transferred onto a polyethylene terephthalate (PET) substrate and fixed at both ends using copper foil electrodes as a flexible textile-fiber-based PVDF energy harvester. Repeated stretching and releasing of PVDF NFF with a strain of 0.05% at 7 Hz produces a maximum peak voltage and current at 76 mV and 39 nA, respectively.

  11. Microstructures and mechanical properties of Co-29Cr-6Mo alloy fabricated by selective laser melting process for dental applications.

    Science.gov (United States)

    Takaichi, Atsushi; Suyalatu; Nakamoto, Takayuki; Joko, Natsuka; Nomura, Naoyuki; Tsutsumi, Yusuke; Migita, Satoshi; Doi, Hisashi; Kurosu, Shingo; Chiba, Akihiko; Wakabayashi, Noriyuki; Igarashi, Yoshimasa; Hanawa, Takao

    2013-05-01

    The selective laser melting (SLM) process was applied to a Co-29Cr-6Mo alloy, and its microstructure, mechanical properties, and metal elution were investigated to determine whether the fabrication process is suitable for dental applications. The microstructure was evaluated using scanning electron microscopy with energy-dispersed X-ray spectroscopy (SEM-EDS), X-ray diffractometry (XRD), and electron back-scattered diffraction pattern analysis. The mechanical properties were evaluated using a tensile test. Dense builds were obtained when the input energy of the laser scan was higher than 400 J mm⁻³, whereas porous builds were formed when the input energy was lower than 150 J mm⁻³. The microstructure obtained was unique with fine cellular dendrites in the elongated grains parallel to the building direction. The γ phase was dominant in the build and its preferential orientation was confirmed along the building direction, which was clearly observed for the builds fabricated at lower input energy. Although the mechanical anisotropy was confirmed in the SLM builds due to the unique microstructure, the yield strength, UTS, and elongation were higher than those of the as-cast alloy and satisfied the type 5 criteria in ISO22764. Metal elution from the SLM build was smaller than that of the as-cast alloy, and thus, the SLM process for the Co-29Cr-6Mo alloy is a promising candidate for fabricating dental devices.

  12. Density improvement of Li{sub 2}TiO{sub 3} pebbles fabricated by wet process

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, K.; Kawamura, H. [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Fuchinoue, K.; Sawada, H.; Watarumi, K.

    1998-03-01

    Lithium titanate (Li{sub 2}TiO{sub 3}) has attracted the attention of many researchers from a point of tritium recovery at low temperature, chemical stability, etc.. The application of small Li{sub 2}TiO{sub 3} sphere has been proposed in some designs of fusion blanket. On the other hand, the wet process is most advantageous as the fabrication method of Li{sub 2}TiO{sub 3} pebbles from a point of mass production, and of reprocessing necessary for effective use of resources and reduction of radioactive wastes. In the preliminary fabrication test, density of Li{sub 2}TiO{sub 3} pebbles was about 40%T.D.. Therefore, in this study, density improvement tests and preliminary characterization of Li{sub 2}TiO{sub 3} pebbles by wet process were performed, noting the aging condition and sintering condition in the fabrication process of the gel-spheres. This study yielded Li{sub 2}TiO{sub 3} pebbles in target range of 80-85%T.D.. (author)

  13. Fabrication of Pd/Pd-Alloy Films by Surfactant Induced Electroless Plating for Hydrogen Separation from Advanced Coal Gasification Processes

    Energy Technology Data Exchange (ETDEWEB)

    Ilias, Shamsuddin; Kumar, Dhananjay

    2012-07-31

    Dense Pd, Pd-Cu and Pd-Ag composite membranes on microporous stainless steel substrate (MPSS) were fabricated by a novel electroless plating (EP) process. In the conventional Pd-EP process, the oxidation-reduction reactions between Pd-complex and hydrazine result in an evolution of NH{sub 3} and N{sub 2} gas bubbles. When adhered to the substrate surface and in the pores, these gas bubbles hinder uniform Pd-film deposition which results in dendrite growth leading to poor film formation. This problem was addressed by introducing cationic surfactant in the electroless plating process known as surfactant induced electroless plating (SIEP). The unique features of this innovation provide control of Pd-deposition rate, and Pd-grain size distribution. The surfactant molecules play an important role in the EP process by tailoring grain size and the process of agglomeration by removing tiny gas bubbles through adsorption at the gas-liquid interface. As a result surfactant can tailor a nanocrystalline Pd, Cu and Ag deposition in the film resulting in reduced membrane film thickness. Also, it produces a uniform, agglomerated film structure. The Pd-Cu and Pd-Ag membranes on MPSS support were fabricated by sequential deposition using SIEP method. The pre- and post-annealing characterizations of these membranes (Pd, Pd-Cu and Pd-Ag on MPSS substrate) were carried out by SEM, EDX, XRD, and AFM studies. The SEM images show significant improvement of the membrane surface morphology, in terms of metal grain structures and grain agglomeration compared to the membranes fabricated by conventional EP process. The SEM images and helium gas-tightness studies indicate that dense and thinner films of Pd, Pd-Cu and Pd-Ag membranes can be produced with shorter deposition time using surfactant. H{sub 2} Flux through the membranes fabricated by SIEP shows large improvement compared to those by CEP with comparable permselectivity. Pd-MPSS composite membrane was subjected to test for long term

  14. DEVELOPMENT OF A FABRICATION PROCESS FOR SOL-GEL/METAL HYDRIDE COMPOSITE GRANULES

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, E; Eric Frickey, E; Leung Heung, L

    2004-02-23

    An external gelation process was developed to produce spherical granules that contain metal hydride particles in a sol-gel matrix. Dimensionally stable granules containing metal hydrides are needed for applications such as hydrogen separation and hydrogen purification that require columns containing metal hydrides. Gases must readily flow through the metal hydride beds in the columns. Metal hydrides reversibly absorb and desorb hydrogen and hydrogen isotopes. This is accompanied by significant volume changes that cause the metal hydride to break apart or decrepitate. Repeated cycling results in very fine metal hydride particles that are difficult to handle and contain. Fine particles tend to settle and pack making it more difficult to flow gases through a metal hydride bed. Furthermore, the metal hydrides can exert a significant force on the containment vessel as they expand. These problems associated with metal hydrides can be eliminated with the granulation process described in this report. Small agglomerates of metal hydride particles and abietic acid (a pore former) were produced and dispersed in a colloidal silica/water suspension to form the feed slurry. Fumed silica was added to increase the viscosity of the feed slurry which helped to keep the agglomerates in suspension. Drops of the feed slurry were injected into a 27-foot tall column of hot ({approx}70 C), medium viscosity ({approx}3000 centistokes) silicone oil. Water was slowly evaporated from the drops as they settled. The drops gelled and eventually solidified to form spherical granules. This process is referred to as external gelation. Testing was completed to optimize the design of the column, the feed system, the feed slurry composition, and the operating parameters of the column. The critical process parameters can be controlled resulting in a reproducible fabrication technique. The residual silicone oil on the surface of the granules was removed by washing in mineral spirits. The granules were

  15. Self-aligned single-mask fabrication process for electro-thermal microactuators using ICP-RIE

    Science.gov (United States)

    Alamin Dow, Ali B.; Gougam, Adel; Kherani, Nazir P.; Rangelow, I. W.

    2013-05-01

    Advances in the miniaturization of semiconductor devices have been made possible by new methods of microfabrication techniques . These advances have stimulated the birth of Micro Electro Mechanical Systems (MEMS) technology which enable the fabrication of a wide variety of sensing and actuating devices of microscopic dimensions . Of particular interest are thermal microactuators which provide large deflections and are compatible with existing IC technologies. In MEMS technology, a well controlled etching process is critical for the fabrication of structures with specific geometry and properties. Increasing demand for intricate semiconductor devices has fueled and motivated researches to develop high precision micromachining techniques . Inductively coupled plasma- Reactive ion etching (ICP-RIE) is capable of producing features with high aspect ratio as high as 90:1. Taking advantage of the notching effect when making a structure from silicon on insulator (SOI), structure release without the use of HF acid has been demonstrated. We report on the development of a self-aligned single-mask process for the fabrication of released and movable MEMS devices. ICP-RIE was used to realize the structures directly out of single crystal silicon. Applying side wall passivation, controlling the ratio of ion flux and radical flux, smooth etching profile can be obtained with high aspect ratio. No wet etching process is required to release the structures as is the case with SOI wafers. This approach overcomes the stiction limitation associated with wet etching and yields good thickness uniformity over the entire structure. Electrothermal microactuators with integrated microgrippers were designed, fabricated and characterized. harvesters.

  16. Transport processes and reduction of IcRn product in YBaCuO/PrBaCuO/YBaCuO ramp-type Josephson junctions

    NARCIS (Netherlands)

    Boguslavskij, Y.M.; Gao, J.; Rijnders, A.J.H.M.; Terpstra, D.; Gerritsma, G.J.; Rogalla, H.

    1993-01-01

    The mechanisms of current passage and the causes of IcRn (critical-current normal-resistance) product reduction of YBCO/PBCO/YBCO ramp-type junctions are analyzed. At PBCO (PrBa2Cu3Ox ) barrier thicknesses L=8-20 nm the junction characteristics are determined by the thickness of the PBCO barrier and

  17. PROCESS TECHNOLOGY OF FABRICATION NO2 GAS SENSOR DEVICES WITH ACTIVE LAYER In2O3

    Directory of Open Access Journals (Sweden)

    Slamet Widodo

    2016-08-01

    Full Text Available This paper discuss the design and fabrication of NO2 gas sensor based on metal oxide using thick film technology was described. The design of gas sensor is consisted of components, i.e. heater, electrode (interdigital fingers and sensitive layer from In2O3 material. This sensor has been designed as multilayers with heater and both electrodes in one surface, in accordance with miniaturisation aspect, heat distribution and less consumption of energy from the sensor device. The heater and electrode were fabricated on alumina substrate (aluminum oxide/Al2O3 with silver paste. The In2O3 layer provides\\ resistance change when it is exposed by NO2 gas. It indicates that this sensor device has a potency to be used as NO2 detector.

  18. Perforated nanocap array: Facile fabrication process and efficient surface enhanced Raman scattering with fluorescence suppression

    Institute of Scientific and Technical Information of China (English)

    Wang Jun; Huang Li-Qing; Tong Hui-Min; Zhai Li-Peng; Yuan Lin; Zhao Li-Hua; Zhang Wei-Wei

    2013-01-01

    Recently,individual reduced-symmetry metal nanostructures and their plasmonic properties have been studied extensively.However,little attention has been paid to the approach to fabricating ordered reduced-symmetry metal nanostructure arrays.In this paper,a novel perforated silver nanocap array with high surface-enhanced Raman scattering (SERS) activity and fluorescence suppression is reported.The array is fabricated by electron beam evaporating Ag onto the perforated barrier layer side of a hard anodization (HA) anodic aluminum oxide (AAO) template.The morphology and optical property of the perforated silver nanocap array are characterized by an atomic force microscope (AFM),a scanning electron microscope (SEM),and absorption spectra.The results of SERS measurements reveal that the perforated silver nanocap array offers high SERS activity and fluorescence suppression compared with an imperforated silver nanocap array.

  19. Metal Nanoparticle Wires Formed by an Integrated Nanomolding-Chemical Assembly Process: Fabrication and Properties

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Xuexin; Park, Myoung-Hwan; Zhao, Yipeng; Berenschot, Erwin; Wang, Zheyao; Reinhoudt, David N.; Rotello, Vincent M.; Huskens, Jurriaan

    2010-12-28

    We report here the use of nanomolding in capillaries (NAMIC) coupled with dithiocarbamate (DTC) chemistry to fabricate sub-50 nm quasi-1D arrays of 3.5 nm core gold nanoparticles (Au NPs) over large areas. Owing to chemical immobilization via the DTC bond, the patterned NP systems are stable in water and organic solvents, thus allowing the surface modification of the patterned Au NP arrays through thiol chemistry and further orthogonal binding of proteins. The electrical properties of these patterned Au NP wires have also been studied. Our results show that NAMIC combined with surface chemistry is a simple but powerful tool to create metal NP arrays that can potentially be applied to fabricate nanoelectronic or biosensing devices.

  20. Fabrication of superhydrophobic polymethylsilsesquioxane nanostructures on cotton textiles by a solution-immersion process.

    Science.gov (United States)

    Shirgholami, Mohammad A; Khalil-Abad, Mohammad Shateri; Khajavi, Ramin; Yazdanshenas, Mohammad E

    2011-07-15

    Superhydrophobic cotton textiles are prepared by a simple, one-step and inexpensive phase separation method under ambient conditions by which a layer of polymethylsilsesquioxane (PMSQ) nanostructures is covered onto the cellulose fibers. By changing the silane precursor concentration, PMSQ nanostructures with various shapes, morphologies and sizes were fabricated. Nanostructures were characterized using SEM, EDS, and attenuated total reflectance FTIR. The wettability of the modified cellulose surfaces was characterized with contact-angle goniometry and sliding angle technique, respectively. The water contact angle of modified cotton is measured to be higher than 150°, which is high enough to exhibit the lotus effect as a result of the superhydrophobicity. Tunable water-repellent properties of the fabric are also demonstrated, with sliding contact angles varying from "sticky" to "slippery" depending upon different nanostructures on the surface of the fibers. It is expected that this simple technique will accelerate the large-scale production of superhydrophobic cellulosic materials with new industrial applications.

  1. Fabrication of polycrystalline diamond refractive X-ray lens by femtosecond laser processing

    Energy Technology Data Exchange (ETDEWEB)

    Kononenko, T.V.; Ralchenko, V.G.; Ashkinazi, E.E.; Konov, V.I. [General Physics Institute of Russian Academy of Sciences, Moscow (Russian Federation); National Research Nuclear University ' ' MEPhI' ' , Moscow (Russian Federation); Polikarpov, M.; Ershov, P. [Immanuel Kant Baltic Federal University, Functional Nanomaterials, Kaliningrad (Russian Federation); Kuznetsov, S.; Yunkin, V. [Institute of Microelectronics Technology RAS, Chernogolovka, Moscow region (Russian Federation); Snigireva, I. [European Synchrotron Radiation Facility, Grenoble (France)

    2016-03-15

    X-ray planar compound refractive lenses were fabricated from a polycrystalline diamond plate grown by chemical vapor deposition, by precise through cutting with femtosecond laser pulses. The lens geometry and the surface morphology were investigated with optical and scanning electron microscopy, while the material structure modification was analyzed by Raman spectroscopy. The results of the preliminary lens test at 9.25-keV X-rays are presented. (orig.)

  2. Poly(pyrrole) microwires fabrication process on flexible thermoplastics polymers: application as a biosensing material

    OpenAIRE

    Garcia-Cruz, Alvaro; Lee, Michael; Zine, Nadia; Sigaud, Monique; Bausells, Joan; Errachid, Abdelhamid

    2015-01-01

    The authors would like to thank to Carole FARRE (Institute of Analytical Sciences, Univ. Lyon I) for the optical microscopy guidance; International audience; We present a new low-cost technology to fabricate poly(pyrrole) microwires (PPy-mu Ws)by micro contact printing (mu CP) and controlled chemical polymerization (mu CP-CCP) using three different techniques ("grafting printing", "addressed printing", and "direct printing". These developed techniques provide a platform to regulate PPy wire s...

  3. Process Development for the Fabrication of Spheroidal Microdevice Packages Utilizing MEMS Technologies

    Science.gov (United States)

    2014-03-27

    out to my roommate Kyle, for teaching me the mysteries of the snatch, sharing countless hours exploring the Miami Valley by bike, being my go-to...matter research. Materials capable of changing their shapes or other physical properties have existed in science fiction under various names for...Unfortunately, both science fiction and theoretical proposals outpace actual scientific breakthroughs and fabrication capabilities; therefore, despite

  4. Design, Fabrication, Processing, and Testing of Micro-Electro-Mechanical Chemical Sensors

    Science.gov (United States)

    1995-12-01

    3.2.2 Electrostatic Theory. .. .. .. .. ... ... ... .... .. 48 3.2.3 Capacitance . .. .. .. .. ... ... .... ... ... .... 50 3.3 Chemical Transport Theory...available to heat the thin film coating, effecting both an intrinsic conductivity change due to the semiconducting material and an extrinsic change due to...other surface-fabricated MOSFET device, except that the metal gate is replaced by an external reference electrode and is coated with a chemically

  5. Molecular electronic junction transport

    DEFF Research Database (Denmark)

    Solomon, Gemma C.; Herrmann, Carmen; Ratner, Mark

    2012-01-01

    Whenasinglemolecule,oracollectionofmolecules,isplacedbetween two electrodes and voltage is applied, one has a molecular transport junction. We discuss such junctions, their properties, their description, and some of their applications. The discussion is qualitative rather than quantitative, and f...

  6. Interfacial Microstructure and Mechanical Properties of Al Alloy/Mg Alloy Laminated Composite Plates Fabricated by Equal Channel Angular Processing

    Institute of Scientific and Technical Information of China (English)

    LI Guorui; ZHAO Dong; ZHAO Yaojiang; ZHOU Bin; WANG Hongxia

    2016-01-01

    KAl (7075) alloy /Mg (AZ31) alloy laminated composite plates were successfully fabricated by the equal channel angular processing (ECAP) by using route A for 1, 2, and 3 passes at 573 K, respectively. After fabrication, the 1-pass ECAPed laminated composite plates were annealed at different temperatures. The microstructure evolution, phase constituent, and bonding strength near the joining interface of Al (7075) alloy /Mg (AZ31) alloy laminated composites plates were evaluated with scanning electron microscopy, X-ray diffraction, and shear tests. The experimental results indicated that a 20 μm diffusion layer was observed at the joining interface of Al (7075) alloy /Mg (AZ31) alloy laminated composites plates fabricated by the 1-pass ECAP, which mainly included Al3Mg2 and Mg17Al12 phases. With the increase of passes, the increase of diffusion layer thickness was not obvious and the form of crack in these processes led to the decrease of bonding strength. For 1-pass ECAPed composites, the thickness of diffusion layer remained unchanged after annealed at 473 K, while the bonding strength reached its maximum value 29.12 MPa. However, after elevating heat treatment temperature to 573 K, the thickness of diffusion layer increased rapidly, and thus the bonding strength decreased.

  7. On the magnetic properties of iron nanostructures fabricated via focused electron beam induced deposition and autocatalytic growth processes

    Science.gov (United States)

    Tu, F.; Drost, M.; Vollnhals, F.; Späth, A.; Carrasco, E.; Fink, R. H.; Marbach, H.

    2016-09-01

    We employ Electron beam induced deposition (EBID) in combination with autocatalytic growth (AG) processes to fabricate magnetic nanostructures with controllable shapes and thicknesses. Following this route, different Fe deposits were prepared on silicon nitride membranes under ultra-high vacuum conditions and studied by scanning electron microscopy (SEM) and scanning transmission x-ray microspectroscopy (STXM). The originally deposited Fe nanostructures are composed of pure iron, especially when fabricated via autocatalytic growth processes. Quantitative near-edge x-ray absorption fine structure (NEXAFS) spectroscopy was employed to derive information on the thickness dependent composition. X-ray magnetic circular dichroism (XMCD) in STXM was used to derive the magnetic properties of the EBID prepared structures. STXM and XMCD analysis evinces the existence of a thin iron oxide layer at the deposit-vacuum interface, which is formed during exposure to ambient conditions. We were able to extract magnetic hysteresis loops for individual deposits from XMCD micrographs with varying external magnetic field. Within the investigated thickness range (2-16 nm), the magnetic coercivity, as evaluated from the width of the hysteresis loops, increases with deposit thickness and reaches a maximum value of ˜160 Oe at around 10 nm. In summary, we present a viable technique to fabricate ferromagnetic nanostructures in a controllable way and gain detailed insight into their chemical and magnetic properties.

  8. 3D Viscoelastic Finite Element Modelling of Polymer Flow in the Fiber Drawing Process for Microstructured Polymer Optical Fiber Fabrication

    DEFF Research Database (Denmark)

    Fasano, Andrea; Rasmussen, Henrik K.; Marín, J. M. R.

    2015-01-01

    The process of drawing an optical fiber from a polymer preform is still not completely understood,although it represents one of the most critical steps in the process chain for the fabrication of microstructuredpolymer optical fibers (mPOFs). Here we present a new approach for the numerical...... the numerical modelling of mPOF drawing has mainly beenbased on principles, such as generalized Newtonian fluid dynamics, which are not able to cope with the elasticcomponent in polymer flow. In the present work, we employ the K-BKZ constitutive equation, a non-linearsingle-integral model that combines both...

  9. Large-scale fabrication of In2S3 porous films via one-step hydrothermal process.

    Science.gov (United States)

    Chen, Fei; Deng, Dan; Lei, Yinlin

    2013-10-01

    Large-scale indium sulfide (In2S3) porous films were fabricated via a facile one-step and non-template hydrothermal process using L-cysteine as a capping agent. The impact of reaction conditions such as reaction time, temperatures, and capping agents on the synthesis of the In2S3 porous films were studied. The morphology, structure, and phase composition of In2S3 porous films were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). The formation process and the optical property of the In2S3 porous films were also evaluated.

  10. Characterization of the nanosized porous structure of black Si solar cells fabricated via a screen printing process

    Institute of Scientific and Technical Information of China (English)

    Tang Yehua; Fei Jianming; Cao Hongbin; Zhou Chunlan; Wang Wenjing; Zhou Su; Zhao Yan; Zhao Lei; Li Hailing; Yan Baojun; Chen Jingwei

    2012-01-01

    A silicon (Si) surface with a nanosized porous structure was formed via simple wet chemical etching catalyzed by gold (Au) nanoparticles on p-type Cz-Si (100).The average reflectivity from 300 to 1200 nm was less than 1.5%.Black Si solar cells were then fabricated using a conventional production process.The results reflected the output characteristics of the cells fabricated using different etching depths and emitter dopant profiles.Heavier dopants and shallower etching depths should be adopted to optimize the black Si solar cell output characteristics.The efficiency at the optimized etching time and dopant profile was 12.17%.However,surface passivation and electrode contact due to the nanosized porous surface structure are still obstacles to obtaining high conversion efficiency for the black Si solar cells.

  11. Fabrication of a Sludge-Conditioning System for Processing Legacy Wastes from the Gunite and Associated Tanks

    Energy Technology Data Exchange (ETDEWEB)

    Randolph, J. D.; Lewis, B. E.; Farmer, J. R.; Johnson, M. A.

    2000-08-01

    The Sludge Conditioning System (SCS) for the Gunite and Associated Tanks (GAATs) is designed to receive, monitor, characterize and process legacy waste materials from the South Tank Farm tanks in preparation for final transfer of the wastes to the Melton Valley Storage Tanks (MVSTs), which are located at Oak Ridge National Laboratory. The SCS includes (1) a Primary Conditioning System (PCS) Enclosure for sampling and particle size classification, (2) a Solids Monitoring Test Loop (SMTL) for slurry characterization, (3) a Waste Transfer Pump to retrieve and transfer waste materials from GAAT consolidation tank W-9 to the MVSTs, (4) a PulsAir Mixing System to provide mixing of consolidated sludges for ease of retrieval, and (5) the interconnecting piping and valving. This report presents the design, fabrication, cost, and fabrication schedule information for the SCS.

  12. Studies on Dyeing Process Variables for Salt Free Reactive Dyeing of Glycine Modified Cationized Cotton Muslin Fabric

    Science.gov (United States)

    Samanta, Ashis Kumar; Kar, Tapas Ranjan; Mukhopadhyay, Asis; Shome, Debashis; Konar, Adwaita

    2015-04-01

    Bleached cotton muslin fabric with or without pre-oxidized with NaIO4 (oxy-cotton) was chemically modified with glycine (amino acid) by pad dry calendar process to investigate the changes in textile properties and its dyeability with reactive dye. This glycine modified cotton incorporates new functional groups producing -NH3 + or -C=NH+ -ion (cationic groups) in acid bath to obtain cationized cotton making it amenable to a newer route of salt free reactive dyeing in acid bath. In the present work the process variables of reactive dyeing in the salt free acid bath for dyeing of amine (glycine) modified cationized cotton were studied and optimized. The present study also includes thorough investigation of changes in important textile related properties and dyeability with reactive dye after such chemical modifications. Between oxidized and unoxidized cotton muslin fabric, unoxidized cotton fabric shows better reactive dye uptake in both conventional alkaline bath dyeing and nonconventional salt free acid bath dyeing particularly for high exhaustion class of reactive dye with acceptable level of colour fastness and overall balance of other textile related properties. Moreover, application of dye fixing agent further improves surface colour depth (K/S) of the glycine treated cotton fabric for HE brand of reactive dyes. Corresponding reaction mechanisms for such modifications were supported by FTIR spectroscopy. Finally unoxidized cotton and pre-oxidized cotton further treated with glycine (amino acid) provide a new route of acid bath salt free reactive dyeing showing much higher dye uptake and higher degree of surface cover with amino acid residue anchored to modified cotton.

  13. Magnetic tunnel junctions with non-collinear anisotropy axes for sensor applications

    CERN Document Server

    Grigorenko, A N

    2003-01-01

    Magnetic tunnel junctions (MTJ) with non-collinear anisotropy axes of magnetic layers have been fabricated for reading head and sensor applications. It is shown that crossed anisotropies of magnetic layers improve sensor sensitivity and time-response compared to the conventional case of aligned anisotropies. The developed micromagnetic model is in good agreement with magnetoresistive properties of fabricated junctions.

  14. Fabrication of Li{sub 2}TiO{sub 3} pebbles by a freeze drying process

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang-Jin, E-mail: lee@mokpo.ac.kr [Department of Advanced Materials Science and Engineering, Mokpo National University, Muan 534-729 (Korea, Republic of); Park, Yi-Hyun [National Fusion Research Institute, Daejeon 305-806 (Korea, Republic of); Yu, Min-Woo [Department of Advanced Materials Science and Engineering, Mokpo National University, Muan 534-729 (Korea, Republic of)

    2013-11-15

    Li{sub 2}TiO{sub 3} pebbles were successfully fabricated by using a freeze drying process. The Li{sub 2}TiO{sub 3} slurry was prepared using a commercial powder of particle size 0.5–1.5 μm and the pebble pre-form was prepared by dropping the slurry into liquid nitrogen through a syringe needle. The droplets were rapidly frozen, changing their morphology to spherical pebbles. The frozen pebbles were dried at −10 °C in vacuum. To make crack-free pebbles, some glycerin was employed in the slurry, and long drying time and a low vacuum condition were applied in the freeze drying process. In the process, the solid content in the slurry influenced the spheroidicity of the pebble green body. The dried pebbles were sintered at 1200 °C in an air atmosphere. The sintered pebbles showed almost 40% shrinkage. The sintered pebbles revealed a porous microstructure with a uniform pore distribution and the sintered pebbles were crushed under an average load of 50 N in a compressive strength test. In the present study, a freeze drying process for fabrication of spherical Li{sub 2}TiO{sub 3} pebbles is introduced. The processing parameters, such as solid content in the slurry and the conditions of freeze drying and sintering, are also examined.

  15. Comparative Study of Laboratory-Scale and Prototypic Production-Scale Fuel Fabrication Processes and Product Characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Douglas W. Marshall

    2014-10-01

    An objective of the High Temperature Gas Reactor fuel development and qualification program for the United States Department of Energy has been to qualify fuel fabricated in prototypic production-scale equipment. The quality and characteristics of the tristructural isotropic coatings on fuel kernels are influenced by the equipment scale and processing parameters. Some characteristics affecting product quality were suppressed while others have become more significant in the larger equipment. Changes to the composition and method of producing resinated graphite matrix material has eliminated the use of hazardous, flammable liquids and enabled it to be procured as a vendor-supplied feed stock. A new method of overcoating TRISO particles with the resinated graphite matrix eliminates the use of hazardous, flammable liquids, produces highly spherical particles with a narrow size distribution, and attains product yields in excess of 99%. Compact fabrication processes have been scaled-up and automated with relatively minor changes to compact quality to manual laboratory-scale processes. The impact on statistical variability of the processes and the products as equipment was scaled are discussed. The prototypic production-scale processes produce test fuels that meet fuel quality specifications.

  16. Microstructural evolution and strengthening behavior in in-situ magnesium matrix composites fabricated by solidification processing

    Energy Technology Data Exchange (ETDEWEB)

    Chelliah, Nagaraj M., E-mail: cmnraj.7@gmail.com [Department of Mechanical Engineering, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab (India); Singh, Harpreet, E-mail: harpreetsingh@iitrpr.ac.in [Department of Mechanical Engineering, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab (India); Surappa, M.K., E-mail: mirle@materials.iisc.ac.in [Department of Materials Engineering, Indian Institute of Science, Bengaluru 560012, Karnataka (India)

    2017-06-15

    In-situ magnesium matrix composites with three different matrix materials (including Mg, AZ91 and AE44 Mg-alloys) were fabricated by injecting cross-linked polymer directly into the molten Mg/Mg-alloys, and having it convert to the 2.5 vol% SiCNO ceramic phase using liquid stir-casting method. In-situ chemical reaction took place within the molten slurry tending to produce 42 and 18 vol% Mg{sub 2}Si crystals in Mg and AE44 matrix composites, respectively but not in AZ91 matrix composite. Microstructural evolution of Mg{sub 2}Si crystals was discussed on the basis of availability of heterogeneous nucleation sites and amount of Al-atoms in the molten slurry. The observed micro-hardness and yield strengths are enhanced by factor of four to three as compared to their unreinforced counterparts, and Taylor strengthening was found to be the predominant strengthening mechanism in magnesium and AE44 matrix composites. Summation model predicted the yield strengths of the fabricated composites more preciously when compared to Zhang and Chen, and modified Clyne models. - Highlights: • In-situ magnesium composites were fabricated using liquid stir-casting method. • In-situ pyrolysis of cross-linked polymer has been utilized to obtain ceramic phases. • Mg{sub 2}Si crystals were formed in magnesium and AE44 matrix composites but not in AZ91 matrix composites. • The variation in size and morphology of Mg{sub 2}Si crystals with matrix materials are discussed. • Strengthening mechanisms in in-situ composites are analyzed and discussed.

  17. Sound absorption of metallic sound absorbers fabricated via the selective laser melting process

    Science.gov (United States)

    Cheng, Li-Wei; Cheng, Chung-Wei; Chung, Kuo-Chun; Kam, Tai-Yan

    2017-01-01

    The sound absorption capability of metallic sound absorbers fabricated using the additive manufacturing (selective laser melting) method is investigated via both the experimental and theoretical approaches. The metallic sound absorption structures composed of periodic cubic cells were made of laser-melted Ti6Al4 V powder. The acoustic impedance equations with different frequency-independent and frequency-dependent end corrections factors are employed to calculate the theoretical sound absorption coefficients of the metallic sound absorption structures. The calculated sound absorption coefficients are in close agreement with the experimental results for the frequencies ranging from 2 to 13 kHz.

  18. Low cost fabrication and assembly process for re-usable 3D polydimethylsiloxane (PDMS) microfluidic networks

    CSIR Research Space (South Africa)

    Land, K

    2011-09-01

    Full Text Available . Phys. Lett. 99, 143703 (2011) Bio-inspired artificial iridophores based on capillary origami: Fabrication and device characterization Appl. Phys. Lett. 99, 144102 (2011) Three-dimensional cellular focusing utilizing a combination of insulator.... Nano- fluid. 3, 1, (2007). 7P. K. Yuen, Lab Chip 8, 1374 (2008). 8S. M. Langelier, E. Livak-Dahl, A. J. Manzo, B. N. Johnson, N. G. Walter, and M. A.Burns, Lab Chip 11, 1679 (2011). 9K. A. Shaikh, K. S. Ryu, E. D. Goluch, J.-M. Nam, J. Liu, C. Shad...

  19. Processing and Electromagnetic Shielding Properties of Multifunctional Metal Composite Knitted Fabric used as Socks

    OpenAIRE

    Yu Zhicai; He Hualing; Han Yutong; Lin Fei; Yang Xiaori; Zhu Shun; Wang Nan; Lin Jia-Horng

    2016-01-01

    In this research, a type of bamboo charcoal polyester (BC-PET)/antibacterial nylon(AN)/stainless steel wire (SSW) metal composite yarn was prepared with a hollow spindle spinning machine, which using the SSW as the core material, the BC-PET and AN as the outer and inner wrapped yarns, respectively. The wrapping numbers was set at 8.0turns/cm for the produced metal composite yarns. Furthermore, a type of plated knitted fabric was designed and produced by using the automatic jacquard knitting m...

  20. The Role of Parieto-Occipital Junction in the Interaction between Dorsal and Ventral Streams in Disparity-Defined Near and Far Space Processing.

    Directory of Open Access Journals (Sweden)

    Aijun Wang

    Full Text Available Neuropsychological and functional MRI data suggest that two functionally and anatomically dissociable streams of visual processing exist: a ventral perception-related stream and a dorsal action-related stream. However, relatively little is known about how the two streams interact in the intact brain during the production of adaptive behavior. Using functional MRI and a virtual three-dimensional paradigm, we aimed at examining whether the parieto-occipital junction (POJ acts as an interface for the integration and processing of information between the dorsal and ventral streams in the near and far space processing. Virtual reality three-dimensional near and far space was defined by manipulating binocular disparity, with -68.76 arcmin crossed disparity for near space and +68.76 arcmin uncrossed disparity for near space. Our results showed that the POJ and bilateral superior occipital gyrus (SOG showed relative increased activity when responded to targets presented in the near space than in the far space, which was independent of the retinotopic and perceived sizes of target. Furthermore, the POJ showed the enhanced functional connectivity with both the dorsal and ventral streams during the far space processing irrespective of target sizes, supporting that the POJ acts as an interface between the dorsal and ventral streams in disparity-defined near and far space processing. In contrast, the bilateral SOG showed the enhanced functional connectivity only with the ventral stream if retinotopic sizes of targets in the near and far spaces were matched, which suggested there was a functional dissociation between the POJ and bilateral SOG.

  1. Optimization of processing parameter for fabrication of polylactic acid/liquid natural rubber/graphene nanoplatelet by tensile properties

    Science.gov (United States)

    Shahdan, Dalila; Ahmad, Sahrim Hj.; Chen, Ruey Shan; Ali, Adilah Mat; Zailan, Farrah Diyana

    2016-11-01

    A study on processing parameter of polylactic acid (PLA) and graphene nanoplatelet (GNP) prepared via melt blending method using Haake Rheomix internal mixer. In this study liquid natural rubber (LNR) was used as compatibilizer and at the same time introducing ductile property into the nanocomposite blending. In order to determine the optimal processing parameter, nanocomposites were fabricated from PLA: LNR with ratio of 90:10, and 0.2 wt. % of graphene nanoplatelet with different mixing parameter condition; mixing temperature, rotor speed and mixing time. The optimal processing parameter was determined from the results of tensile testing. An optimum processing parameter of polymer nanocomposite was obtained at 180 °C of mixing temperature, 100 rpm of mixing speed and 14 min of mixing time. The SEM micrographs confirmed the dispersion of GNP in the PLA matrix.

  2. Fabrication and densification enhancement of SiC-particulate-reinforced copper matrix composites prepared via the sinter-forging process

    Institute of Scientific and Technical Information of China (English)

    Mohammadmehdi Shabani; Mohammad Hossein Paydar; Mohammad Mohsen Moshksar

    2014-01-01

    The fabrication of copper (Cu) and copper matrix silicon carbide (Cu/SiCp) particulate composites via the sinter-forging process was investigated. Sintering and sinter-forging processes were performed under an inert Ar atmosphere. The influence of sinter-forging time, tempera-ture, and compressive stress on the relative density and hardness of the prepared samples was systematically investigated and subsequently com-pared with that of the samples prepared by the conventional sintering process. The relative density and hardness of the composites were enhanced when they were prepared by the sinter-forging process. The relative density values of all Cu/SiCp composite samples were observed to decrease with the increase in SiC content.

  3. Simple Fabrication Process for 2D ZnO Nanowalls and Their Potential Application as a Methane Sensor

    Directory of Open Access Journals (Sweden)

    Zhan-Shuo Hu

    2013-03-01

    Full Text Available Two-dimensional (2D ZnO nanowalls were prepared on a glass substrate by a low-temperature thermal evaporation method, in which the fabrication process did not use a metal catalyst or the pre-deposition of a ZnO seed layer on the substrate. The nanowalls were characterized for their surface morphology, and the structural and optical properties were investigated using scanning electron microscopy (SEM, X-ray diffraction (XRD, transmission electron microscopy (TEM, and photoluminescence (PL. The fabricated ZnO nanowalls have many advantages, such as low growth temperature and good crystal quality, while being fast, low cost, and easy to fabricate. Methane sensor measurements of the ZnO nanowalls show a high sensitivity to methane gas, and rapid response and recovery times. These unique characteristics are attributed to the high surface-to-volume ratio of the ZnO nanowalls. Thus, the ZnO nanowall methane sensor is a potential gas sensor candidate owing to its good performance.

  4. Simple fabrication process for 2D ZnO nanowalls and their potential application as a methane sensor.

    Science.gov (United States)

    Chen, Tse-Pu; Chang, Sheng-Po; Hung, Fei-Yi; Chang, Shoou-Jinn; Hu, Zhan-Shuo; Chen, Kuan-Jen

    2013-03-20

    Two-dimensional (2D) ZnO nanowalls were prepared on a glass substrate by a low-temperature thermal evaporation method, in which the fabrication process did not use a metal catalyst or the pre-deposition of a ZnO seed layer on the substrate. The nanowalls were characterized for their surface morphology, and the structural and optical properties were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and photoluminescence (PL). The fabricated ZnO nanowalls have many advantages, such as low growth temperature and good crystal quality, while being fast, low cost, and easy to fabricate. Methane sensor measurements of the ZnO nanowalls show a high sensitivity to methane gas, and rapid response and recovery times. These unique characteristics are attributed to the high surface-to-volume ratio of the ZnO nanowalls. Thus, the ZnO nanowall methane sensor is a potential gas sensor candidate owing to its good performance.

  5. A facile electrodeposition process to fabricate corrosion-resistant superhydrophobic surface on carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Yi [State Key Lab of Oil and Gas Reservoir Geology and Exploitation (Southwest Petroleum University), Rd. 8, Xindu District, Chengdu City, Sichuan Province 610500 (China); School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu City, Sichuan Province 610500 (China); He, Yi, E-mail: chemheyi@swpu.edu.cn [State Key Lab of Oil and Gas Reservoir Geology and Exploitation (Southwest Petroleum University), Rd. 8, Xindu District, Chengdu City, Sichuan Province 610500 (China); School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu City, Sichuan Province 610500 (China); Luo, Pingya, E-mail: luopy@swpu.edu.cn [State Key Lab of Oil and Gas Reservoir Geology and Exploitation (Southwest Petroleum University), Rd. 8, Xindu District, Chengdu City, Sichuan Province 610500 (China); Chen, Xi; Liu, Bo [School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu City, Sichuan Province 610500 (China)

    2016-04-15

    Graphical abstract: - Highlights: • A facile fabrication of superhydrophobic film was obtained on carbon steel. • Composition of superhydrophobic film is iron palmitate. • The film exhibits excellent chemical stability and good self-cleaning effect. • Corrosion of C45 steel is significantly inhibited with superhydrophobic surface. - Abstract: Superhydrophobic Fe film with hierarchical micro/nano papillae structures is prepared on C45 steel surface by one-step electrochemical method. The superhydrophobic surface was measured with a water contact angle of 160.5 ± 0.5° and a sliding angle of 2 ± 0.5°. The morphology of the fabricated surface film was characterized by field emission scanning electron microscopy (FE-SEM), and the surface structure seems like accumulated hierarchical micro-nano scaled particles. Furthermore, according to the results of Fourier transform infrared spectra (FT-IR) and X-ray photoelectron spectroscopy (XPS), the chemical composition of surface film was iron complex with organic acid. Besides, the electrochemical measurements showed that the superhydrophobic surface improved the corrosion resistance of carbon steel in 3.5 wt.% NaCl solution significantly. The superhydrophobic layer can perform as a barrier and provide a stable air–liquid interface which inhibit penetration of corrosive medium. In addition, the as-prepared steel exhibited an excellent self-cleaning ability that was not favor to the accumulation of contaminants.

  6. Composition-graded nanowire solar cells fabricated in a single process for spectrum-splitting photovoltaic systems.

    Science.gov (United States)

    Caselli, Derek; Liu, Zhicheng; Shelhammer, David; Ning, Cun-Zheng

    2014-10-08

    Nanomaterials such as semiconductor nanowires have unique features that could enable novel optoelectronic applications such as novel solar cells. This paper aims to demonstrate one such recently proposed concept: Monolithically Integrated Laterally Arrayed Multiple Band gap (MILAMB) solar cells for spectrum-splitting photovoltaic systems. Two cells with different band gaps were fabricated simultaneously in the same process on a single substrate using spatially composition-graded CdSSe alloy nanowires grown by the Dual-Gradient Method in a chemical vapor deposition system. CdSSe nanowire ensemble devices tested under 1 sun AM1.5G illumination achieved open-circuit voltages up to 307 and 173 mV and short-circuit current densities as high as 0.091 and 0.974 mA/cm(2) for the CdS- and CdSe-rich cells, respectively. The open-circuit voltages were roughly three times those of similar CdSSe film cells fabricated for comparison due to the superior optical quality of the nanowires. I-V measurements were also performed using optical filters to simulate spectrum-splitting. The open-circuit voltages and fill factors of the CdS-rich subcells were uniformly larger than the corresponding CdSe-rich cells for similar photon flux, as expected. This suggests that if all wires can be contacted, the wide-gap cell is expected to have greater output power than the narrow-gap cell, which is the key to achieving high efficiencies with spectrum-splitting. This paper thus provides the first proof-of-concept demonstration of simultaneous fabrication of MILAMB solar cells. This approach to solar cell fabrication using single-crystal nanowires for spectrum-splitting photovoltaics could provide a future low-cost high-efficiency alternative to the conventional high-cost high-efficiency tandem cells.

  7. Controlled fabrication of advanced functional structures on the nanoscale by means of electron beam-induced processing

    Science.gov (United States)

    Schmidt, Sebastian W.; Foucher, Johann; Penzkofer, Christian; Irmer, Bernd

    2013-05-01

    The controlled deposition of materials by means of electron beam induced processing (EBIP) is a well-established patterning method, which allows for the fabrication of nanostructures with high spatial resolution in a highly precise and flexible manner. Applications range from the production of ultrathin coatings and nanoscaled conductivity probes to super sharp atomic force microscopy (AFM) tips, to name but a few. The latter are typically deposited at the very end of silicon or silicon-nitride tips, which are fabricated with MEMS technologies. EBIP therefore provides the unique ability to converge MEMS to NEMS in a highly controllable way, and thus represents an encouraging opportunity to refine or even develop further MEMS-based features with advanced functionality and applicability. In this paper, we will present and discuss exemplary application solutions, where we successfully applied EBIP to overcome dimensional and/or functional limitations. We therefore show the fabrication stability and accuracy of "T-like-shaped" AFM tips made from high density, diamond-like carbon (HDC/DLC) for the investigation of undercut structures on the base of CDR30-EBD tips. Such aggressive CD-AFM tip dimensions are mandatory to fulfill ITRS requirements for the inspection of sub-28nm nodes, but are unattainable with state-of-art Si-based MEMS technologies today. In addition to that, we demonstrate the ability of EBIP to realize field enhancement in sensor applications and the fabrication of cold field emitters (CFE). For example: applying the EBIP approach allows for the production of CFEs, which are characterized by considerably enhanced imaging resolution compared to standard thermal field emitters and stable operation properties at room temperature without the need for periodic cathode flashing - unlike typical CFEs. Based on these examples, we outline the strong capabilities of the EBIP approach to further downscale functional structures in order to meet future demands in the

  8. A study on NiGe-contacted Ge n+/p Ge shallow junction prepared by dopant segregation technique

    Science.gov (United States)

    Tsui, Bing-Yue; Shih, Jhe-Ju; Lin, Han-Chi; Lin, Chiung-Yuan

    2015-05-01

    In this work, the effect of dopant segregation on the NiGe/n-Ge contact is studied by experiments and first-principles calculations. Both Al-contacted and NiGe-contacted n+/p junctions were fabricated. Phosphorus and arsenic ions were Implanted Before Germanide (IBG) formation or Implanted After Germanide (IAG) formation. The NiGe-contacted junction always exhibit higher forward current than the Al-contacted junction due to dopant segregation. First principles calculations predict that phosphorus atoms tend to segregate on both NiGe side and Ge side while arsenic atoms tend to segregate at Ge side. Since phosphorus has higher activation level and lower diffusion coefficient than arsenic, we propose a phosphorus IBG + arsenic IAG process. Shallow n+/p junction with junction depth 90 nm below the NiGe/Ge interface is achieved. The lowest and average contact resistivity is 2 × 10-6 Ω cm2 and 6.7 × 10-6 Ω cm2, respectively. Methods which can further reduce the junction depth and contact resistivity are suggested.

  9. Biological implications of lab-on-a-chip devices fabricated using multi-jet modelling and stereolithography processes

    Science.gov (United States)

    Zhu, Feng; Macdonald, Niall; Skommer, Joanna; Wlodkowic, Donald

    2015-06-01

    Current microfabrication methods are often restricted to two-dimensional (2D) or two and a half dimensional (2.5D) structures. Those fabrication issues can be potentially addressed by emerging additive manufacturing technologies. Despite rapid growth of additive manufacturing technologies in tissue engineering, microfluidics has seen relatively little developments with regards to adopting 3D printing for rapid fabrication of complex chip-based devices. This has been due to two major factors: lack of sufficient resolution of current rapid-prototyping methods (usually >100 μm ) and optical transparency of polymers to allow in vitro imaging of specimens. We postulate that adopting innovative fabrication processes can provide effective solutions for prototyping and manufacturing of chip-based devices with high-aspect ratios (i.e. above ration of 20:1). This work provides a comprehensive investigation of commercially available additive manufacturing technologies as an alternative for rapid prototyping of complex monolithic Lab-on-a-Chip devices for biological applications. We explored both multi-jet modelling (MJM) and several stereolithography (SLA) processes with five different 3D printing resins. Compared with other rapid prototyping technologies such as PDMS soft lithography and infrared laser micromachining, we demonstrated that selected SLA technologies had superior resolution and feature quality. We also for the first time optimised the post-processing protocols and demonstrated polymer features under scanning electronic microscope (SEM). Finally we demonstrate that selected SLA polymers have optical properties enabling high-resolution biological imaging. A caution should be, however, exercised as more work is needed to develop fully bio-compatible and non-toxic polymer chemistries.

  10. 退火对Zn扩散的影响及其在InGaAs探测器中的应用%Annealing process on Zn diffusion and its application in fabrication of InGaAs detectors

    Institute of Scientific and Technical Information of China (English)

    邓洪海; 龚海梅; 魏鹏; 朱耀明; 李淘; 夏辉; 邵秀梅; 李雪; 缪国庆; 张永刚

    2012-01-01

    采用闭管扩散方式,对不同结构的异质结外延材料In0.81Al0.19As/In0.81Ga0.19As、InAs0.6P0.4/In0.8Ga0.2As、InP/In0.53Ga0.47As实现了Zn元素的P型掺杂,采用扫描电容显微技术(SCM)和二次离子质谱(SIMS)研究了在芯片制备中高温快速热退火(RTP)处理环节对p-n结结深的影响.结果表明:由于在这3种异质结外延材料中掺杂的Zn元素并未完全激活,导致扩散深度明显大于p-n结结深;高温快速热退火处理并不会显著影响结深的变化,扩散完成后的p-n结深度可以近似为器件最终的p-n结结深;计算了530℃下Zn在In0.81Al0.19As、InAs0.6P0.4、InP中的扩散系数D分别为1.327×10-12 cm2/s、1.341 10-12 cm2/s、1.067× 10-12 cm2/s.%Zn diffusion to form P type doped structure with sealed-ampoule method on different kinds of heterostructure epitaxial materials was carried out, such as In0.82Al0.19As/In0.81Ga0.19As, InAs0.6P0.4/In0.8Ga0.2Asand InP/In0.53Ga0.47As. Scanning capacitance microscopy (SCM) and secondary ion mass spectroscopy (SIMS) techniques were adopted to investigate the process of rapid thermal annealing process (RTP) on p-n junction depth variation in the process of the detectors fabrication. The result indicates that due to the doped Zn in these three heterostructure epitaxial materials is not completely activated, the diffusion depth is deeper than the p-n junction depth in evidence. And RTP has almost no effect on junction depth variation which implies that the p-n junction depth after the diffusion process could be considered to the ultimate p-n junction depth of the detector. The diffusion coefficients D of Zn into In0.81Al0.19As, InAs0.6P0.4 and InP under 530 ℃ are figured out, which is 1.327 × 10-12 cm2/s, 1.341 ×10-12 cm7s, 1.067 ×10-12 cm2/s respectively.

  11. Fast transient response of novel Peltier junctions

    Energy Technology Data Exchange (ETDEWEB)

    Hoyos, G.E.; Rao, K.R.; Jerger, D.

    1977-01-01

    The fast transient response of a thermoelectric (TE) cooler with novel geometry is discussed. This geometry involves conical semiconductor legs whose hot to cold junction cross-sectional area ratios can be varied. The novel TE junctions are fabricated such that the thermal capacitance and electrical conductance are decreased while simultaneously increasing the thermal resistance. The experimental apparatus which includes the vacuum system, power supplies, pulse and control circuitry, sensing and measuring instrumentation etc. is described. With narrow pulse width and large amplitudes, additional cooling of the order of 45/sup 0/C below the steady-state maximum with recovery times in the range of 1 to 3 sec is obtained.

  12. Evolution of Pore Size Distribution and Mean Pore Size in Lotus-type Porous Magnesium Fabricated with Gasar Process

    Institute of Scientific and Technical Information of China (English)

    Yuan LIU; Yanxiang LI; Huawei ZHANG; Jiang WAN

    2006-01-01

    The effect of gas pressures on the mean pore size, the porosity and the pore size distribution of lotus-type porous magnesium fabricated with Gasar process were investigated. The theoretical analysis and the experimental results all indicate that there exists an optimal ratio of the partial pressures of hydrogen pH2 to argon pAr for producing lotus-type structures with narrower pore size distribution and smaller pore size. The effect of solidification mode on the pore size distribution and pore size was also discussed.

  13. Development of automated welding process for field fabrication of thick walled pressure vessels. Fourth quarter technical progress report for period ending September 30, 1979

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-01-01

    Progress in developing an automated welding process for the field fabrication of thick walled pressure vessels is reported. Plans for the demonstration facility, for nondestructive testing, and for the procurement of materials are discussed. (LCL)

  14. Hybrid fabrication process of additive manufacturing and direct writing for a 4 X 4 mm matrix flexible tactile sensor

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Sang Gu; Lee, In Hwan [Chungbuk National University, Chungju (Korea, Republic of); Lee, Kyong Chang [Pukyong National University, Busan (Korea, Republic of)

    2015-09-15

    Various machines require data from their external environments for safety and/or accuracy. In this respect, many sensors that mimic the human sensory system have been investigated. Among these, tactile sensors may be useful for obtaining data on the roughness of, and external forces acting upon, an object. Several tactile sensors have been developed; however, these are typically fabricated via a series of complex processes, and hence are unsuitable for volume manufacturing. In this paper, we report a fabrication process for a 4 X 4 mm matrix flexible sensor element using layered manufacturing and direct-write technology. A composite composed of photocurable resin and Multi-walled carbon nanotubes (MWCNTs) was used as the sensing material. The MWCNTs were mixed with the photocurable resin using ultrasonic dispersion, and the liquid mixture exhibited excellent piezoresistive properties following curing using ultraviolet light. The used photocurable resin is flexible and elastic after curing. Therefore, the composite material can be bent and deformed. To use this composite material with the flexible sensor, dispensing characteristics were examined using direct-write technology. For the acquisition of sensor data, a commercial pin-header was inserted and photocurable resin was filled up to the height of pin-header and cured . Then, the composite material was dispensed onto the pin-header as a sensing material. Using this process, a flexible sensor with piezoresistive properties was formed.

  15. Structural and mechanical evaluations of a topology optimized titanium interbody fusion cage fabricated by selective laser melting process.

    Science.gov (United States)

    Lin, Chia-Ying; Wirtz, Tobias; LaMarca, Frank; Hollister, Scott J

    2007-11-01

    A topology optimized lumbar interbody fusion cage was made of Ti-Al6-V4 alloy by the rapid prototyping process of selective laser melting (SLM) to reproduce designed microstructure features. Radiographic characterizations and the mechanical properties were investigated to determine how the structural characteristics of the fabricated cage were reproduced from design characteristics using micro-computed tomography scanning. The mechanical modulus of the designed cage was also measured to compare with tantalum, a widely used porous metal. The designed microstructures can be clearly seen in the micrographs of the micro-CT and scanning electron microscopy examinations, showing the SLM process can reproduce intricate microscopic features from the original designs. No imaging artifacts from micro-CT were found. The average compressive modulus of the tested caged was 2.97+/-0.90 GPa, which is comparable with the reported porous tantalum modulus of 3 GPa and falls between that of cortical bone (15 GPa) and trabecular bone (0.1-0.5 GPa). The new porous Ti-6Al-4V optimal-structure cage fabricated by SLM process gave consistent mechanical properties without artifactual distortion in the imaging modalities and thus it can be a promising alternative as a porous implant for spine fusion.

  16. One step phase separation process to fabricate superhydrophobic PVC films and its corrosion prevention for AZ91D magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Na; Li, Jicheng; Bai, Ningning; Xu, Lan; Li, Qing, E-mail: liqingswu@163.com

    2016-07-15

    Graphical abstract: - Highlights: • Independent superhydrophobic polyvinyl chloride (PVC) film was prepared by phase separation process. • The superhydrophobic PVC film showed excellent stability in acid, alkali and salt corrosive solutions. • This film was prepared on magnesium surface protecting it from corrosion. • This method was simple and universal. - Abstract: A one step, simple fabrication method to prepare independent superhydrophobic polyvinyl chloride (PVC) coating is reported in this paper. The rough surface structure and low surface energy could be simply obtained only by a phase separation process. The independent PVC superhydrophobic film was also applied on AZ91D magnesium alloy. Scanning electron microscopy (SEM), water contact angle measurements, electrochemical test and adhesion tests have been performed to characterize the surface morphology, wettability, anti-corrosion and adhesion strength of independent PVC film and superhydrophobic magnesium alloy respectively. The results indicated that whether it was the PVC film or superhydrophobic magnesium, they show static contact angles higher than 150°, excellent anti-corrosion effect and adhesion strength. We believed that the presented method could provide a straightforward and simple route to fabricate low-cost and anti-corrosion coating on various substrate materials. Moreover, this one step process may find potential application in the field of industry because of its simplicity and universality.

  17. Influence of processing conditions on strut structure and compressive properties of cellular lattice structures fabricated by selective laser melting

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Chunlei, E-mail: c.qiu@bham.ac.uk [School of Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Yue, Sheng [School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA (United Kingdom); Adkins, Nicholas J.E.; Ward, Mark; Hassanin, Hany [School of Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Lee, Peter D., E-mail: peter.lee@manchester.ac.uk [School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA (United Kingdom); Withers, Philip J., E-mail: p.j.withers@manchester.ac.uk [School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA (United Kingdom); Attallah, Moataz M., E-mail: m.m.attallah@bham.ac.uk [School of Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)

    2015-03-25

    AlSi10Mg cellular lattice structures have been fabricated by selective laser melting (SLM) using a range of laser scanning speeds and powers. The as-fabricated strut size, morphology and internal porosity were investigated using optical microscopy (OM), scanning electron microscopy (SEM) and X-ray microtomography (micro-CT) and correlated to the compressive properties of the structure. Strut diameter was found to increase monotonically with laser power while the porosity was largest at intermediate powers. Laser scanning speed was found to thicken the struts only at slow rates while the porosity was largest at intermediate speeds. High speed imaging showed the melt pool to be larger at high laser powers. Further the melt pool shape was found to vary cyclically over time, steadily growing before becoming increasingly instable and irregularly shaped before abruptly falling in size due to splashing of molten materials and the process repeating. Upon compressive loading, lattice deformation was homogeneous prior to the peak stress before falling sharply due to the creation of a (one strut wide) shear band at around 45° to the compression axis. The specific yield strength expressed as the yield stress/(yield stress of the aluminium × relative density) is not independent of processing conditions, suggesting that further improvements in properties can be achieved by process optimisation. Lattice struts failed near nodes by a mixture of ductile and brittle fracture.

  18. FABRIC QUALITY CONTROL SYSTEMS

    Directory of Open Access Journals (Sweden)

    Özlem KISAOĞLU

    2006-02-01

    Full Text Available Woven fabric quality depends on yarn properties at first, then weaving preparation and weaving processes. Defect control of grey and finished fabric is done manually on the lighted tables or automatically. Fabrics can be controlled by the help of the image analysis method. In image system the image of fabrics can be digitized by video camera and after storing controlled by the various processing. Recently neural networks, fuzzy logic, best wavelet packet model on automatic fabric inspection are developed. In this study the advantages and disadvantages of manual and automatic, on-line fabric inspection systems are given comparatively.

  19. Subwavelength Microstructures Fabrication by Self-Organization Processes in Photopolymerizable Nanocomposite

    Directory of Open Access Journals (Sweden)

    I. Yu. Denisyuk

    2012-01-01

    Full Text Available This paper describes our research results on nanometers sizes subwavelength nanostructure fabrication by UV curing of special nanocomposite material with self-organization and light self-focusing effects. For this purpose, special UV curable nanocomposite material with a set of effects was developing: light self-focusing in the photopolymer with positive refractive index change, self-organization based on photo-induced nanoparticles transportation, and oxygen-based polymerization threshold. Both holographic and projection lithography writing methods application for microstructure making shows geometrical optical laws perturbation as result of nanocomposite self-organization effects with formation of nanometers-sized high-aspect-ratio structures. Obtained results will be useful for diffraction limit overcoming in projection lithography as well as for deep lithography technique.

  20. PVDF core-free actuator for Braille displays: design, fabrication process, and testing

    Science.gov (United States)

    Levard, Thomas; Diglio, Paul J.; Lu, Sheng-Guo; Gorny, Lee J.; Rahn, Christopher D.; Zhang, Q. M.

    2011-04-01

    Refreshable Braille displays require many, small diameter actuators to move the pins. The electrostrictive P(VDF-TrFECFE) terpolymer can provide the high strain and actuation force under modest electric fields that are required of this application. In this paper, we develop core-free tubular actuators and integrate them into a 3 × 2 Braille cell. The films are solution cast, stretched to 6 μm thick, electroded, laminated into a bilayer, rolled into a 2 mm diameter tube, bonded, and provided with top and bottom contacts. Experimental testing of 17 actuators demonstrates significant strains (up to 4%). A novel Braille cell is designed and fabricated using six of these actuators.