镀锌焊接钢丝网水泥在一种模拟海洋环境中的疲劳特性

使正常养护２８ｄ的７０个镀锌焊接钢丝网水泥试件持续受弯，最外层钢丝的计算应力达到腐蚀下容许值２０７Ｎ／ｍｍ＾２，再放入自制的以７０℃干燥６０ｍｉｎ和４３℃，３．５％ＮａＣｌ溶液浸渍３０ｍｉｎ为一周期的忆速模拟海洋环境实验系统中，分别承受荷载－腐蚀共同作用１、３、７和１８个月（４８０￣８６４０个周期），再对这些试件进行弯曲疲劳－腐蚀试验。分析评估了影响钢丝网水泥抗荷载－腐蚀性能的因素，给出了破坏概率     

The effect of surface recombination on the frequency-dependentcharacteristics of an ion-implanted GaAs OPFET

The effect of modulation frequency and surface recombination on the characteristics of an ion-implanted GaAs OPFET is determined analytically. The drain-source current is found to decrease with the increase in both modulation frequency and trap center density. The current changes significantly with the trap center density only when the latter is greater than 10²⁰/m². The threshold voltage does not change appreciably with the modulation frequency as in a silicon OPFET. However, the increased in the trap center density causes V_T to increase in the enhancement device and decrease in the depletion device. Further, V_T increases under the normally ON condition and decreases under the normally OFF condition with an increase in the photon absorption coefficient in GaAs. Some anomalous behavior is observed for higher values of the absorption coefficient     

Clinical experience of trabeculotomy for the surgical treatment of aniridic glaucoma

OBJECTIVE: The purpose of this study is to determine the efficacy of initial trabeculotomy in the patient with aniridic glaucoma. DESIGN: Clinical charts were reviewed. PARTICIPANTS: Twenty-nine eyes of 16 patients with aniridia were studied. INTERVENTION: Glaucoma surgery was performed. As an initial procedure, trabeculotomy was performed in 12 eyes, other surgery was performed in 17 eyes (trabeculectomy, 5; goniotomy, 5; other, 7). MAIN OUTCOME MEASURES: Success was defined as an intraocular pressure (IOP) of 21 mmHg or lower, and no further surgery was performed. RESULTS: Ten (83%) of 12 eyes obtained IOP control after first (6 eyes) or second (4 eyes) trabeculotomy with a mean follow-up period of 9.5 years. Five eyes maintained visual acuity of 20/40 to 20/200. No serious complications were found after trabeculotomy. Three (18%) of 17 eyes were controlled with the first glaucoma surgery other than trabeculotomy (goniotomy, trabeculectomy, trabeculectomy combined with trabeculotomy, and Molteno implant). Good IOP control was obtained in 8 (47%) of 17 eyes after several surgeries with a mean follow-up period of 10.4 years. Four of 17 eyes became phthisical. CONCLUSION: This study suggests that trabeculotomy is the preferred initial operation for uncontrolled glaucoma with aniridia.     

Brain abscess in solid organ transplant recipients receiving cyclosporine-based immunosuppression

There is currently a stark therapeutic void in the treatment of evolving stroke. Although P-selectin is rapidly expressed by hypoxic endothelial cells in vitro, the functional significance of P-selectin expression in stroke remains unexplored. In order to identify the pathophysiological consequences of P-selectin expression and to identify P-selectin blockade as a potential new approach for the treatment of stroke, experiments were performed using a murine model of focal cerebral ischemia and reperfusion. Early P-selectin expression in the postischemic cerebral cortex was demonstrated by the specific accumulation of radiolabeled anti-murine P-selectin IgG, with the increased P-selectin expression localized to the ipsilateral cerebral microvascular endothelial cells by immunohistochemistry. In experiments designed to test the functional significance of increased P-selectin expression in stroke, neutrophil accumulation in the ischemic cortex of mice expressing the P-selectin gene (PS +/+) was demonstrated to be significantly greater than that in homozygous P-selectin-null mice (PS -/-). Reduced neutrophil influx was accompanied by greater postischemic cerebral reflow (measured by laser Doppler) in the PS -/- mice. In addition, PS -/- mice demonstrated smaller infarct volumes (5-fold reduction, P<.05) and improved survival compared with PS +/+ mice (88% versus 44%, P<.05). Functional blockade of P-selectin in PS +/+ mice using a monoclonal antibody directed against murine P-selectin also improved early reflow and stroke outcome compared with control mice, with reduced cerebral infarction volumes noted even when the blocking antibody was administered after occlusion of the middle cerebral artery. These data are the first to demonstrate a pathophysiological role for P-selectin in stroke and suggest that P-selectin blockade may represent a new therapeutic target in the treatment of stroke.     

Growth of polysilicon and silicide films for MOS-VLSI application

Doped and undoped polycrystalline silicon films were grown byapcvd and thermal evaporation techniques. The effect of growth and annealing conditions on the crystalline nature of the films and their properties were studied by electrical, optical, x-ray diffraction andsem techniques. Metal silicides such as TiSi₂ and PtSi₂ were prepared by co-evaporation technique over polysilicon layers to study their suitability in microelectronic applications. Some of the properties of polysilicon and silicides are discussed.     

Analysis of indentation-derived effective elastic modulus of metal-ceramic multilayers

A numerical study was undertaken to study the elastic property of metal-ceramic multilayered composites derived from indentation testing. The model system features alternating thin films of aluminum (Al) and silicon carbide (SiC), free from any effect due to the underlying substrate. The anisotropic composite elastic response was obtained by simulating overall loading of the multilayer structure. Finite element modeling of instrumented indentation was then employed to calculate the indentation-derived modulus using the unloading portion of the load–displacement curve. The results from indenting the homogenized composite (with the built-in multilayer property) and from indenting the real multilayers (with Al and SiC layers explicitly accounted for) were compared. It was found that an indentation depth beyond approximately 8–10 initial layer thicknesses is sufficient to yield a valid composite elastic response. The effective modulus thus obtained is representative of the out-of-plane modulus of the multilayer composite.     

Physical Properties of Pyridinium Fluorohydrogenate, [pyridine · H+][H2F3]−

Ionic liquids (ILs), also referred to as molten salts, have found application as electrolytes for batteries and super-capacitors, in electroplating baths, as designer solvents, and as reaction media. A few of the desired properties of a super-capacitor electrolyte are nonflammability, thermal stability, and electrochemical stability. ILs containing aromatic cations have been shown to have low viscosity which results in a high electrochemical conductivity. There is a delicate balance between increasing the thermal stability, or decreasing the melting point, and increasing the electrochemical conductivity of the IL. This study focuses on pyridinium fluorohydrogenate, [pyridine · H⁺][H₂F₃]⁻. Pyridinium fluorohydrogenate has been synthesized by the reaction of pyridine and anhydrous hydrofluoric acid. This IL has a relatively high electrical conductivity (~98 mS · cm⁻¹ at 23 °C), a wide electrochemical window, and a boiling point of 186 °C. A stable gel can also be formed by combining [pyridine · H⁺][H₂F₃]⁻ and a super absorbent polymer such as polyacrylic acid. The gel adds mechanical stability to the matrix while not greatly affecting the conductivity of the IL.     

An efficacious “naked-eye” selective sensing of cyanide from aqueous solutions using a triarylmethane leuconitrile

A triarylmethane dye 1 detects CN^? from water and shows remarkable selectivity over other anions and dramatic color changes, in solution as well as when dyed. The pH stability of 1 in the range of 1.2–10.7 offers additional advantage in the sensing process under physiological conditions.     

Oxidation of polycyclic aromatic hydrocarbons with hydrogen peroxide catalyzed by Iron(III)porphyrins

A variety of iron-metallated functional porphyrins have been synthesized and their catalytic activity to oxidize polycyclic aromatic hydrocarbons, (PAHs) using hydrogen peroxide as oxidant was investigated. It was found that iron-metallated porphyrins bearing strong electronegative groups at β-pyrrolic positions show an exceptionally high catalytic efficiency.     

Thermal and Optical Properties of Zn<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>Mn<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Te Diluted Magnetic Semiconductor Studied by Photoacoustic Spectroscopic Method

Using photoacoustic spectroscopy, the composition-dependent absorption coefficient (α), thermal diffusivity (σ), and optical bandgap (E _g) of Zn_1−x Mn _x Te diluted magnetic semiconductor have been measured. For higher Mn compositions, the absorption spectrum of the Zn–Mn–Te system consists of three regions, viz., the high absorption region, the exponential region, and the weak absorption tail. The bandgap follows a nonlinear variation with composition, showing a downward bowing with a minimum around x = 0.31 as a consequence of the electro-negativity difference between the substituted atoms. The composition-dependent band-edge effective mass of the carriers does not show the bowing behavior indicating that the momentum matrix is not the same for all the Zn_1−x Mn _x Te alloys due to different lattice constants. The absorption spectra show that the transition is allowed and direct.