小封装LC OC-48光纤收发模块的设计

安捷伦HFCT-5942 2.488GB/s LC小封装光纤收发模块是符合SONET和SDH标准,管脚为2×10的短距离单模光纤收发模块。 文中给出了三种不同应用的参考设计。在这些设计中,HFCT.5942光纤收发模块与以下芯片联接     

China Likely to Resume Oil Futures Soon

China is likely to resume operation of its oil futures this year, according to reports from the media about a futures conference organized by the Shanghai Futures Exchange (SHFE) in late May. "As China has become an important oil producer and consumer,the demand for our own oil futures market emerges,which will help China oil-related enterprises hedge risks," said Li Ruisheng, vice president of PetroChina's refining and marketing company.     

混合集成型光学拾音器的设计与制作

通过混合集成型结构光学拾音器的光学设计和芯片设计，制作了包含微光学棱镜，光电探测器和信号放大电路的混合集成型光学拾音器。经过测试，发现有较好的信号输出特性，表明混合集成型光学拾音器已基本研制成功。     

An analysis of the coupling of an injection laser diode to a planar LiNbO3waveguide

Calculated butt coupling efficiency between a GaAlAs double heterostructure laser and a single-mode LiNbO3Ti-diffused optical waveguide is presented in this paper as a function of the transverse displacement, the angular alignment, the longitudinal separation between the laser and the waveguide end surfaces, the radiation field of the laser diode and its dependence on the laser diode structure, and the mode profile of the waveguide and its dependence on experimental diffusion parameters. The maximum efficiency is less than 40 percent because of the mismatch between the waveguide mode and the laser radiation, caused primarily by the experimental limitations in their structures. The effect of the reflection of the waveguide end surface on the laser oscillation has also been estimated.     

Direct analysis of transient stability: Experience with the Taipower system

A direct method for transient stability analysis of a multimachine power system is presented. Emphasis is placed on the detailed development and evaluation of the proposed method in transient stability assessment. An energy-type Lyapunov function, taking into account the effect of transfer conductance, is introduced first. The potential energy boundary surface method is then adopted to determine the critical energy value quickly. The main computational burden in the direct method lies in the reduction of the admittance matrices. In this paper, an efficient reduction technique incorporating the sparsity technique and compensation theory is developed. Finally, the proposed method was tested on the Taipower system, which is the only power system in Taiwan. The results obtained confirm the validity and accuracy of the proposed method, and hence demonstrate the superiority and potential of the direct method in real power system applications.     

Hyperdynamic circulation of cirrhotic rats: role of substance P and its relationship to nitric oxide

BACKGROUND: It has been suggested that excessive formation of nitric oxide (NO) is responsible for the hyperdynamic circulation observed in portal hypertension. Substance P is a neuropeptide partly cleared by the liver and causes vasodilatation through the activation of the endothelial NO pathway. However, there are no previously published data concerning the plasma level of substance P in cirrhotic rats and its relationship to NO. METHODS: Plasma concentrations of substance P and nitrate/nitrite (an index of NO production) were determined in control rats and cirrhotic rats with or without ascites using an enzyme-linked immununosorbent assay and a colorimetric assay, respectively. In addition, systemic and portal hemodynamics were evaluated by a thermodilution technique and catheterization. RESULTS: Cirrhotic rats with and without ascites had a lower systemic vascular resistance (2.6 +/- 0.2 and 3.9 +/- 0.4 mmHg ml(-1) x min x 100 g body weight, respectively) and higher portal pressure (14.6 +/- 0.6 and 11.3 +/- 1.8 mmHg) than control rats (6.5 +/- 0.3 mmHg x ml(-1) x min x 100 g BW and 6.8 +/- 0.2 mmHg, respectively, P < 0.05), and cirrhotic rats with ascites had the lowest systemic vascular resistance. Plasma levels of nitrate/nitrite progressively increased in relation to the severity of liver dysfunction (control rats, 2.7 +/- 0.5 nmol/ml; cirrhotic rats without ascites, 5.6 +/- 1.3 nmol/ml; cirrhotic rats with ascites, 8.3 +/- 2.2 nmol/ml; P < 0.05). Cirrhotic rats with ascites displayed higher plasma values of substance P (57.7 +/- 5.9 pg/ml) than cirrhotic rats without ascites (37.9 +/- 3.1 pg/ml, P < 0.05) and control rats (30.1 +/- 1.0 pg/ml, P < 0.05). There was no significant difference in plasma substance P values between control rats and cirrhotic rats without ascites (P > 0.05). No correlation was found between plasma levels of substance P and nitrate/nitrite (r = 0.318, P > 0.05). CONCLUSIONS: Excessive formation of NO may be responsible, at least partly, for the hemodynamic derangements in cirrhosis. Although substance P may not participate in the initiation of a hyperdynamic circulation in cirrhosis, it may contribute to the maintenance of the hyperdynamic circulation observed in cirrhotic rats with ascites.     

关于M序列的自相关函数的一点注记

本文讨论了Ｍ序列的自相关性，并证明了：当０＜｜ｔ－２＾ｎ－１｜≤［ｎ－１／２］时，｜ＣＭ（ｔ）｜≤２＾ｎ－１。     

Fracture behaviour of unmodified and rubber-modified epoxies under hydrostatic pressure

The fracture toughness and uniaxial tensile yield strengths of unmodified and CTBN-rubber-modified epoxies were measured under hydrostatic pressure. The purpose of these experiments was to learn how suppressing cavitation in rubber particles affects the deformation mechanisms and the fracture toughness of rubber-modified epoxy. It was found that the cavitation of CTBN-rubber could be suppressed at a relatively low pressure (between 30 and 38 M Pa). With cavitation suppressed, the rubber particles are unable to induce massive shearyielding in the epoxy matrix, and the fracture toughness of the rubber-modified epoxy is no higher than that of the unmodified epoxy in the pressure range studied. Unmodified epoxy shows a brittle-to-ductile transition in fracture toughness test. The reason for this transition is the postponement of the cracking process by applied pressure.Work performed while on a sabbatical leave at the University of Michigan.