Wetting of silicon single crystal by silver and tin,and their interfaces

A study of wetting of silicon single crystals and electrode metals was undertaken to investigate the wetting mechanisms and to clarify the interfaces between the silicon wafer and silver and tin. The experiments were performed using a high-temperature surface tension measuring equipment in vacuum and 5% H₂/Ar atmospheres (10⁵ Pa). The contact angles were measured by taking photographs through a telescope during the wetting experiment. Silicon was wetted by silver with a contact angle of 42°, whereas it was not wetted by tin in vacuum and in the 5% H₂/Ar atmosphere. However, heat treatment of silicon in vacuum or 5% H₂/Ar atmosphere prior to the wetting experiment reduced the contact angles compared to the cases with no heat treatment. The bonding interfaces between silicon and silver are also discussed.     

Optical code-multiplex transmission by gold sequences

This paper describes a transmission system that uses passive optical multiplexing with gold sequences. The system is composed of an optical fiber network and electrical matched filters, and allows forN + 2asynchronous stations each with a gold sequence address of lengthN. We analyze, theoretically, the error probability of the system and verify the results with experimental data. We further show that, in the synchronous case, the maximal error-free multiplexity is, in practice,N + 1. The features of the System are as follows: 1) The system uses optical multiplexing instead of conventional electrical multiplexing. 2) The number of assignable addresses is large. 3) In the asynchronous case, each station can transmit a code at any time irrespective of other stations' timings.     

The activity of 17alpha-hydroxylase/C17-C20 lyase in the ovaries of immature hypophysectomized rats treated with recombinant FSH combined with various doses of human chorionic gonadotropin

For ex vivo gene therapy, superoxide dismutase (SOD) must be secreted into the extracellular space and delivered to damaged cells. Recombinant DNA technique can be used to produce a secretory protein that is fused to a non-secretory protein and a signal peptide of another secretory protein gene. We constructed a secretable SOD eukaryotic expression vector which expresses human SOD cDNA by fusing it to the signal peptide DNA sequence of the human interleukin-2 (IL-2) gene. The ILSOD cDNA constructed by PCR-based gene expression was ligated into the multicloning site of the pRc/CMV plasmid (pRc/CMV-ILSOD). Rat lung epithelial like cells (L2 cells) were transfected with pRc/CMV-ILSOD by lipofection. The extracellular SOD activity of ILSOD-L2 cells (transfected cells with pRc/CMV-ILSOD) was 3 times as high as that of host cells. We used the xanthin (X)/xanthin oxidase (XO) system to produce superoxide anions at the extracellular space. We initially investigated the direct cytotoxicity of superoxide anions upon cells. Host and ILSOD-L2 cells were killed by using X/XO, although the sensitivity of the ILSOD-L2 cells to X/XO induced cytotoxicity was significantly decreased compared with that of host cells. The production of lipid peroxidated substances in the host in the presence of X/XO increased to about twice the control (absence of X/XO) level. However, that of ILSOD-L2 cells did not change in the presence of X/XO. Therefore, ILSOD-L2 cells were resistant to X/XO induced lipid peroxidation. These findings indicated that ILSOD gene transfection protected against direct oxidant stress by X/XO. We then investigated the effect of extracellular SOD secreted from ILSOD-L2 cells on extracellular superoxide anion induced cytotoxicity in normal cells. The conditioned media of host cells had no significant effect upon X/XO induced cytotoxicity. However, the conditioned media of ILSOD-L2 cells protected against X/XO induced cytotoxicity. Furthermore, the conditioned medium of ILSOD-L2 cells was more effective than that of host cells against the production of lipid peroxidated substances by normal cells under conditions of oxidative stress. These results indicated that non-secretable protein could be delivered to target cells by means of DNA engineering. This strategy could thus provide an ex vivo means of applying gene therapy using non-secretable proteins.     

Sources of ethnic differences between Asian American and White American college students on measures of depression and social anxiety.

This study tested an affect-specific explanation for the Asian and White American differences in depression and social anxiety. Construal of the self as independent or interdependent in relation to others (H. R. Markus & S. Kitayama, see record 1991-23978-001) was hypothesized to be 1 possible way in which culture may be expressed in individuals' psychological functioning, which in turn was hypothesized to be linked specifically to social anxiety. College students (N?=?348; 183 White Americans and 165 Asian Americans) completed self-report measures of depression, social anxiety, and self-construals. Asian Americans scored significantly higher than White Americans on measures of depression and social anxiety. When the covariance between depression and social anxiety was statistically controlled, ethnicity and self-construal variables were found, as predicted, to be associated with measures of social anxiety but not depression. These findings suggest a more differentiated perspective on the relations between culture, ethnicity, and emotional distress. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Endoscopic management of subcutaneous gunshot wound with irrigation technique

The application of the endoscope to the treatment of gunshot wounds has never been reported to our knowledge, with the exception of the laparoscope and the sigmoidscope in abdominal gunshot wounds. We report a patient with a subcutaneous gunshot wound who was treated endoscopically using the irrigation technique. The patient was a 25-year-old man who had been shot in the upper arm. The bullet was found near the thoracic spine via radiograph. At surgery the endoscope was inserted into the wound and irrigation was started. Excellent views could be obtained by irrigation, and the endoscope was advanced along the path of the bullet. The bullet and several fragments were removed with two additional small incisions. The method described herein seems beneficial in that (1) it is less invasive than conventional surgical debridement with a long incision, (2) it may provide information helpful in diagnosing the condition and the location of the bullet and its path, and (3) saline irrigation may have a cleansing effect.     

DETERMINATION METHOD OF VARIABLE DIFFUSION COEFFICIENTS OF HYGROSCOPIC MATERIAL FROM DRYING RATE CURVES OF THE SINGLE PARTICLE

The concentration dependency of diffusion coefficients of hygroscopic materials can usually only be calculated by cumbersome experimental techniques.

Taking the diffusion rate in the fictious steady state with the same mean moisture concentration as in the regular regime of the drying process of a spherical hygroscopic particle (which means the drying period not influenced by initial moisture distributions) into account, a simple method is proposed to estimate the dependency of diffusion coefficients on the moisture concentration for hygroscopic materials from drying rate curves of the single particle.     

A novel contact slider/gimbal to raise recording density in flexible disk drives

 We developed the soft and full-contact head/gimbal assembly (HGA) for card-size flexible disk drive. We used a 150 μg slider and a flexible beam of BeCu alloy to realize soft contact. We designed our HGA using FEM simulation and optimized the load force, the load pressure, and the stress on the beam. We report the mechanical characteristics, read-write signals, and the vibration of the HGA. A new type loading/unloading mechanism was developed for the removable flexible medium, and confirmed the reliability of the loading/unloading mechanism by the deformation of the HGA and the loaded medium. Received: 5 July 2001/Accepted: 1 November 2001     

Grain growth in nanocrystalline NbAl3 prepared by mechanical alloying

Grain growth and its kinetics were studied on an intermetallic compound, NbAl₃ powder prepared by mechanical alloying of elemental Nb and Al powders for 1.8 Ms in an argon atmosphere at ambient temperature. The initial and grown grain sizes were measured from the X-ray line broadening of as-alloyed and annealed powders. Isochronal annealing of mechanically alloyed powders from 573 to 1373 K indicated that substantial grain growth occurs only in a temperature range of 1048 to 1173 K and ceases at 1273 K regardless of anneal time. Accordingly isothermal annealing of 1.8 to 18 ks was carried out at 1048, 1073 and 1098 K to obtain the grain growth kinetic that is described by In (dD/dt) = In(r_o/3) –2.0 In D where D is the measured grain size and r _o a constant. This r _o depends on temperature according to r _o=r_o exp (– Q/kT) where Q is the activation energy for grain growth, k the Boltzmann constant and T the absolute temperature. Arrhenius plots of r _o against the reciprocal of temperature yield a straight line, from whose slope the activation energy for grain growth is deduced to be 162±2 kJ mol^–1. Of significance is the fact that the ultimate grain size at 1273 K is approximately 70 nm, which will not grow by further annealing even at 1373 K.On leave from Ibaraki University, Japan.     

Characterization of doped Nd-based superconductors

Y-, Dy-, and Gd-doped neodymium (Nd) superconductors (RE_0.1Nd_0.9Ba₂-Cu₃O_y) exhibited sharp resistivity transitions at 92 K. DC susceptibility measurements gave a common curve with diamagnetic onsets at 93 K and transitions complete at 50 K. Lattice constants for an assumed orthorhombic structure were calculated from X-ray diffraction measurements. These values were used to create a simulated diffraction pattern with 2 values and relative intensities that agreed well with observed values. Oxygen contents determined by instrumental neutron activation analysis, ranged from 14.7 to 15.1±0.1 wt%(6.59y in O _y 6.73). This range of oxygen content for YBa₂Cu₃O _y gives 50–60 K transitions in marked contrast to the 92 K (midpoint) values for the materials of this study.     

Improvement of assurance including security for wireless sensor networks using dispersed data transmission

Assurance networks are one of the essential technologies of New-generation Networks. Assurance is defined as the capability of guaranteeing functional and non-functional system properties such as dependability, security, timeliness and adaptability to heterogeneous and changing requirements. Assurance is essential for sustainable networks and this research focused specifically on providing assurance for WSNs. Node capture attacks are one prospective kind of attack on WSNs. To reduce negative effect of node capture attacks, we have previously proposed secure decentralized data transfer. In this proposed method, it was assumed that multiple paths were in place. In this paper as well, we again propose using the multipath routing method. To make multiple paths fit our previously proposed method, we have modified ATR (Augmented Tree Based Routing). We have conducted simulation experiments using our proposed method in a network simulator. The results show that our previously proposed method is effective in both cases in which the network size is small or large. In addition, we conducted other simulation experiments to measure several aspects of the assurance of our method. We measured in terms of varying parameters such as node densities, distance between the source and the destination nodes, and so on. Additionally, our method is more assured than the single path-based method.