The correlation of texture and magnetic properties in Co-Cr films

This investigation focuses on the correlation between the crystallographic orientation of grains with respect to magnetic properties in Co-Cr films. Based on a distribution measured for the (0002) crystallographic pole densities, modified formulae describing the texture were used to calculate the coercivity Hc, the squareness ratio Rs (Mr⊥/TMs) and the anisotropy field Ha for Co-Cr films. In general, calculated values for the coercive force He agreed well with the measured values. The calculated Rs⊥. values were much larger than the measured ones, however, indicating that the influence of the demagnetizing field and the magnetostriction on the orientation of the magnetization cannot be neglected. On leave from Institute of Computing Technology, Academia Sinica, P.O.Box 2704-6, Beijing, P.R. China.     

A hybrid spreading/despreading function with good SNR performancefor band-limited DS-CDMA

Code-division multiple-access (CDMA) implemented with direct-sequence spread spectrum (DS/SS) signaling is a promising multiplexing technique for cellular telecommunications services. The efficiency of a direct-sequence spread-spectrum code-division multiple-access (DS-CDMA) system depends heavily on the shape of the spectrum of the spread signal. Maximum efficiency is obtained with an ideal brick-wall bandpass spectrum. There are two approaches toward achieving such a spectrum. One is to use a simple spreader that produces a broad spectrum and then follow it with a precise, high order filter to band limit the spectrum. A second approach, which is the approach taken in this paper, is to use a spreader that produces a spectrum close to the ideal spectrum and then employ a simple filter to control the out-of-band power. The proposed spreader/despreader is based on a simple hybrid function and can be easily implemented. An analysis provides a compact expression for the signal-to-noise ratio (SNR) of a RAKE receiver. The expression includes the effects of baseband, intermediate frequency (IF) and RF filtering as well as the effects of the spectral densities of the spreading/despreading functions. The analysis shows that the proposed spreader/despreader yields superior performance over a conventional pseudo noise (PN) spreading/despreading mechanism     

一种有效的并行汉字／字符串相似检索技术

本文提出了一种有效的并行汉字／字符串相似检索技术．通过引入搜索状态向量及字符一模式匹配向量，该技术将字符串匹配比较转化为简单的整数字位运算，通过对字符串方向相反的搜索有效地实现了多处理机对汉字／字符串的并行相似检索．文中也给出了并行实现算法，同时分析了算法的复杂性．     

新型NTC热敏电阻材料—含铜Mn系铁氧体的研究

研究了含铜Mn系铁氧体的阻温特性,目的是用廉价的铁氧体取代价格昂贵的、传统的Mn Ni Co氧化物、负温度系数热敏电阻。通过Cu~(2+)离子取代Fe~(2+)离子或Mn~(2+)离子,及改变淬火工艺,可以改变Mn系铁氧体整体电阻率ρ和材料参数B,得到可与传统氧化物器件相比拟的性能。     

ZG31Mn2Si履带板的铸造工艺

采用ＺＧ３１Ｍｎ２Ｓｉ替代ＺＧＭｎ１３生产拖拉机和推土机履带板．改进铸造工艺，可以生产出合格的铸件；经淬火、低温退火处理，其基体组织为马氏体，属强韧性钢种，能够切削加工．     

THE STATISTICAL DISTRIBUTION OF EXTREME VALUES OF WAVE-CURRENT FORCES ACTING ON SLENDER CIRCULAR CYLINDER IN IRREGULAR WAVES

Based on model test,the statistical distribution of extreme values of wave-current in-line forces acting on vertical circular cylinder is analyzed in this paper.It is shownthat the results calculated by the simplified method,proposed by authors,agree well with the testdata;Weibull distribution is also adoptable in the region of high KC number, and the shapeparameter a and scale parameter β are related well with KC number respectively.     

瞬态瑞利面波技术在地震勘探方面的应用研究

运用瞬态瑞利面小勘探方法可以在寻找激发岩性和提供静校正所需参数方面取得好的效果。     

可配置非幂方分频器的全新设计方法

本文采用基于计数空间完全划分和周期插入控制计数过程方法设计了非幂方分频器,采用这种全新思路设计的非幂方分频器分频范围很宽,分频输出对后续分频支持好,非常适用于通讯接口中的波特率时钟设计.此外,这种设计思路对系统定时电路和节拍控制电路设计也有一定的借鉴意义.     

Fabrication of 1.55 μm VCSELs on Si using metallic bonding

Using AuGeNiCr multilayered metals as the wafer bonding medium, long-wavelength GaInAsP/InP vertical cavity surface emitting lasers employing Al-oxide/Si as the upper and lower distributed Bragg reflectors were fabricated on Si substrate with the bonding interface formed outside the vertical cavity surface emitting laser cavity. Laser emission at 1.545 μm was measured under pulsed operations near room temperature. The low-temperature metallic bonding process demonstrates a great potential in device fabrication