钨钼活化烧结机理

主要介绍了添加少量Ｎｉ－Ｃｏ时钨，钼的低温烧结特性，对比了纯钨，Ｗ－Ｃｏ，Ｗ－Ｎｉ，Ｗ－Ｎｉ－Ｃｏ，纯钼，Ｍｏ－Ｃｏ，Ｍｏ－Ｎｉ，Ｍｏ－Ｎｉ－Ｃｏ烧结体系，测算了这些体系的烧结活化能，研究了其低温烧结机理，发现Ｎｉ－Ｃｏ对钨，钼的烧结具有最好的活化效果，说明镍与钴的共同加入对钨，钼的烧结具有协同活化作用。     

分流液压转向牵引计算的展开图及其应用

本文论及分流液压转向牵引计算的概念,方法及其展开图,并且提供了计算机绘制的展开图和应用实例。     

核医学成像技术中计算机的应用

由于计算机和核医学的结合,各种成像方法的计算机化医学图像层析技术正在迅速发展,并开始广泛应用。本文介绍各类成像技术中计算机的应用,特别评述其最近进展,并提出了今后的展望。     

长输管道外防护层的选择与应用

文章介绍了目前国内外长输管道外防护技术的特点和防护层应用的现状,分析了常用防腐蚀材料的防腐蚀性能。指出在山区复杂地形条件下,应考虑环境条件和施工条件,并通过技术经济分析对管道外防腐蚀层进行合理选择。     

推力矢量控制技术在导弹上的应用及发展

简要介绍了推力矢量控制技术的概念,分析了推力矢量控制的基本原理及特点.在简要分析其技术发展历程的基础上,给出了导弹推力矢量技术的现状和发展趋势.     

Fuzzy control of nitrogen removal in predenitrification process using ORP.

In order to meet increasingly stringent discharge standards, new applications and control strategies for the sustainable removal of nitrogen from wastewater have to be implemented. In the past years, numerous studies have been carried out dealing with the application of fuzzy logic to improve the control of the activated sludge process. In this paper, fuzzy control strategies of predenitrification systems are presented that could lead to better effluent quality and, in parallel, to a reduction of chemicals consumption. Extensive experimental investigations on lab scale plant studies have shown that there was excellent correlation between nitrate concentration and ORP value at the end of the anoxic zone. Results indicated that ORP could be used as an on-line fuzzy control parameter of nitrate recirculation and external carbon addition. The optimal value of ORP to control nitrate recirculation and external carbon addition was - 86 +/- 2 mV and - 90 +/- 2 mV, respectively. The results obtained with real wastewater also showed the good performance and stability of the fuzzy controllers independently from external disturbances. The integrated control structure of nitrate recirculation and external carbon addition in the predenitrification system is also presented.     

An efficient approach for calculating the dispersions of photonic-crystal fibers: design of the nearly zero ultra-flattened dispersion

A novel and efficient approach is proposed to calculate the dispersions of the guided modes of the photonic-crystal fibers (PCFs). Based on the vector boundary-element method (VBEM), the surface integral equations for the first and second derivatives of the propagation constants with respect to the wavelength are explicitly derived. Compared with the three-point finite-difference approach, which needs to solve and search three effective indexes near the interested wavelength, this approach can determine the dispersions of the PCFs by only solving one effective index at this wavelength based on the derived formulations. This novel approach saves over 60% computing time without losing the accuracy. Based on this approach, a novel four-ring PCF is designed by optimizing only three geometrical parameters to achieve the nearly zero ultra-flattened dispersion property. Compared with previously presented dispersion-flattened PCFs, the design procedure for the four-ring structure could be more efficient and easier because relatively lesser parameters need to be optimized.     

A Study of AlN Films Prepared by Arc Ion Plating

Hexagonal AlN films have been obtained by arc ion plating at different negative biases ,X-ray diffraction and scanning electron microscopy results show that AlN films with smooth surfaces and (002) preferred orientation are obtained at low biases ,whereas those with coarse surfaces and (100) preferred orientation are obtained at high biases,The formation mechanism of AlN is analyzed and the experiment results are discussed,The effect of bias on adhesion strength has also been examined.     

PetaStar: a petabit photonic packet switch

This paper presents a new petabit photonic packet switch architecture, called PetaStar. Using a new multidimensional photonic multiplexing scheme that includes space, time, wavelength, and subcarrier domains, PetaStar is based on a three-stage Clos-network photonic switch fabric to provide scalable large-dimension switch interconnections with nanosecond reconfiguration speed. Packet buffering is implemented electronically at the input and output port controllers, allowing the central photonic switch fabric to transport high-speed optical signals without electrical-to-optical conversion. Optical time-division multiplexing technology further scales port speed beyond electronic speed up to 160 Gb/s to minimize the fiber connections. To solve output port contention and internal blocking in the three-stage Clos-network switch, we present a new matching scheme, called c-MAC, a concurrent matching algorithm for Clos-network switches. It is highly distributed such that the input-output matching and routing-path finding are concurrently performed by scheduling modules. One feasible architecture for the c-MAC scheme, where a crosspoint switch is used to provide the interconnections between the arbitration modules, is also proposed. With the c-MAC scheme, and an internal speedup of 1.5, PetaStar with a switch size of 6400 /spl times/ 6400 and total capacity of 1.024 petabit/s can be achieved at a throughput close to 100% under various traffic conditions.