Representation of a digital magnetic recording channel

A representation or model of a digital magnetic recording channel which has value both as an expression of the transfer characteristics of the channel and as a tool for use in the design and development of digital coding techniques for that channel is presented     

Evidence of shear ligament toughening in TiAl-base alloys

Shear ligament toughening is a process by which fracture resistance of a material is enhanced as the result of the redundant deformation and shear fracture of intact ligaments that are formed in the crack wake. A recent micromechanical model has suggested that shear ligament toughening is responsible for the resistance-curve fracture behavior observed in lamellar TiAl-base alloys. In this article, various aspects of the shear ligament-toughening mechanism are evaluated by performing critical experiments. Experimental evidence supporting the presence of shear ligament toughening in TiAl-base alloys is presented together with a quantitative comparison of the proposed model against experimental data. Both the experimental results and model calculations indicate that the resistance-curve fracture behavior in lamellar TiAl-base alloys is indeed a manifestation of shear ligament toughening.     

基于模糊回归的电价预测

利用模糊隶属函数建立了复合回归模型；在复合回归模型基础上，建立了模糊非线性回归模型；给出了求非对称模糊分布的上下边界的线性规划方法；实例应用验证了方法的正确性。     

Mass transfer in liquid-fluidized and spouted beds of ion exchange resin at low Reynolds number

Rates of mass transfer from the liquid phase to small ion exchange resin particles (0.78 mm in mean diameter) in fluidized and spouted beds were studied experimentally. Dilute aqueous solution of sodium hydroxide was fed into the beds of strong cation exchange resin and the exit concentration of the solution was determined by conductivity measurement. In spouted beds, the initial conversion and K_l increased with bed height, but decreased with fluid flowrate. The model, applying material balance of the reactant and axisymmetric flow of fluid in the annulus of a spouted bed, predictions of the initial conversion in spouted beds are satisfactory. In fluidized beds, the obtained mass transfer coefficients were correlated and compared with other works.     

机械CAD软件系统面向对象建模方法研究

以面向对象的减速器ＣＡＤ系统的分析建模为例，对机械ＣＡＤ系统采用面得对象技术建模的方法进行了研究，总结出此类ＣＡＤ系统面向对象建模的一般特点。     

Role of metabolism in ethyl carbamate-induced suppression of antibody response to sheep erythrocytes in female Balb/C mice

A possible role of metabolism by cytochrome P450 (P450) in ethyl carbamate-induced suppression of the antibody response to a T-cell-dependent antigen, sheep erythrocytes (SRBCs), was investigated in female Balb/C mice. When mice were treated with ethyl carbamate intraperitoneally for 14 consecutive days at 25, 50, 100, 200 and 400 mg/kg, the antibody response was significantly suppressed from 200 mg/kg. These doses also caused a decrease in thymus weight. An acute dosing of ethyl carbamate at 1 g/kg also caused not only a significant suppression of the antibody response, but also a decrease in thymus weight. The antibody response was most likely to be the IgM antibody response, which was demonstrated in a haemagglutination study. When mice were pretreated with phenobarbital (80 mg/kg) for 3 days to induce P450 enzymes, followed by administration of ethyl carbamate intraperitoneally for 7 consecutive days, the antibody response was more suppressed than in saline-pretreated controls. Moreover, a study using aminoacetonitrile, a P450 inhibitor, showed that the antibody response suppressed by ethyl carbamate was completely recovered by the inhibitor. The present results suggest that metabolism of ethyl carbamate by P450 may be the critical pathway to produce metabolites capable of suppressing the antibody response.     

A simulation study of long throw sputtering for diffusion barrierdeposition into high aspect vias and contacts

Modified sputtering techniques, such as long throw sputtering, collimation, and ionized sputtering, have been proposed to improve VLSI topography bottom coverage by narrowing the angular distribution of the sputter flux at the substrate and reducing subsequent flux shadowing at the bottom of topography. This paper first investigates a number of unique aspects involved in the simulation of long throw sputter systems. In particular, time importance of inhomogeneous film density and nonunity sticking coefficients are addressed. The second part of the paper presents a simulation study of long throw sputtering, providing a comparison to collimated and standard sputtering systems. The simulations are performed using the SIMSPUD/SIMBAD ballistic deposition tool. SIMSPUD is used to study film uniformity over a 300-mm wafer and to generate angular distributions at the center and edge of the wafer. The ability of SIMBAD to simulate directed sputtering systems is verified by direct comparison to Ti films deposited into oxide trenches. The importance of modeling the film microstructure is demonstrated by comparison between cross-sectional SEM's micrograph for evaporation and modeling results, such as long throw sputtering with a variety of substrate/target spacings, typical “standard” as well as “collimated” systems. SEM's of overhang structures and simulations are also presented to demonstrate nonunity sticking during the co-sputtering of TiW     

Plastic buckling analysis of a circular cylinder considering plastic compressibility

In this study the plastic buckling analysis of a circular cylinder under axial compression is carried out considering plastic compressibility. For the stability analysis, the linearized finite element equation is derived and the general elastic-plastic constitutive equation is formulated. The Drucker-Prager plastic potential is used to describe the plastic compressible yielding and the strength-differential effect. The influence of plastic compressibility on the buckling load is investigated for a circular cylinder.