铸铝激光熔融处理后的组织与性能

应用光学和电子显微镜及显微硬度计研究了铸造Al-Si合金经激光表面熔融处理后的组织和性能。指出,组织分熔化区、过度区和基体三层。在熔化区中树枝状先共晶α相的平均宽度由原始组织的20～40μm细化到2～3μm,同时共晶组织也被大大细化。这些变化使显微硬度值由67.4提高至109～115.     

基于神经网络的模拟电路故障诊断优化近似方法

本文提出了线性电阻电路故障诊断的一种神经网络优化方法。其基本思想是应用Ｈｏｐｆｉｅｌｄ网络原理来处理Ｌ１范数问题，以此来进行诊断。对实例的计算证明此法是可行的。     

Soliton position jitter caused by periodic amplification andself-frequency shift

The formula for soliton timing jitter due to self-frequency shift and pulse width fluctuations caused by spontaneous-emission noise has been deduced. Such timing jitter is compared with that caused by the carrier frequency shift due to spontaneous-emission noise. It is shown that the timing jitter due to the self-frequency shift can be as large as the timing jitter due to carrier frequency shift when the total transmission distance is 100 times longer than the soliton period     

硫化锌掺钴对电子结构和光学性质的影响

根据密度泛函理论对钴掺硫化锌周围的品格进行了结构优化,计算得到了钴杂质周围的晶体结构、电子态密度分布和吸收光谱.计算结果表明,由于Co原子掺入ZnS晶格常数减小,导致晶格畸变;带隙变窄;吸收峰展宽至更长波长区域.     

CONE-DIRECTED CONTINGENT DERIVATIVES AND GENERALIZED PREINVEX SET-VALUED OPTIMIZATION

By using cone-directed contingent derivatives, the unified necessary and suffi-cient optimality conditions are given for weakly and strongly minimal elements respectively in generalized preinvex set valued optimization.     

同时含有稀土元素La Ce Pr Nd的材料的电子探针定量分析方法

研制了稀土六硼化物单晶LaB_6、CeB_6、PrB_6和NdB_6电子探针分析标样。根据X-射线峰位表和实测的特征X-射线谱,考察分析了La、Ce、Pr和Nd元素谱线之间的干扰情况,发现分析谱线PrLα_1受到L_αLβ_1线严重的干扰。以混合稀土金属为试样,采用扣除谱线重叠强度的背底非对称测量等方法对L_n、Ce、Pr和Nd进行了电子探针定量分析,其结果与荧光X-射线光谱分析结果符合较好。     

多路FM－SCM光波系统研制

介绍我们研制的多路ＦＭ－ＳＣＭ（调频副载波复用）光波系统及其性能，讨论了ＳＣＭ光波系统的噪声。该系统主要可用于多路ＣＡＴＶ光纤传输。采用Ｆ－Ｐ腔ＬＤ和ＰＩＮ－ＦＥＴ接收组件，通过系统优化，实现了接收端输出电视图象信号ＳＮＲ＞５５ｄＢ。     

Dynamic Reservation Multiple Access (DRMA): A new multiple access scheme for Personal Communication System (PCS)

To improve the spectrum efficiency of integrated voice and data services in Personal Communication System (PCS), several reservation-type multiple access schemes, such as Packet Reservation Multiple Access (PRMA), Dynamic Time Division Multiple Access (D-TDMA), Resource Auction Multiple Access (RAMA), etc., have been proposed. PRMA uses the data packet itself to make a channel reservation, and is inefficient in that each unsuccessful reservation wastes one slot. However, it does not have a fixed reservation overhead and offers shorter access delay. On the other hand, fixed reservation overhead is unavoidable in both RAMA and D-TDMA. Compared to D-TDMA and PRMA, RAMA is superior in the sense that its slot assignment is independent of the traffic load. But its implementation is difficult. With these observations, a new reservation protocol, called Dynamic Reservation Multiple Access (DRMA), is proposed in this paper. With this new protocol, the success probability of channel access is greatly improved at the expense of slightly increased system complexity. It solves the problem of inefficiency in PRMA, but without introducing the fixed reservation overhead as in D-TDMA and RAMA. In addition, it is more suited to the dynamic behavior of the integrated traffic because there is no fixed boundary between voice and data slots (which is mandatory in D-TDMA and RAMA). Our numerical results indicate that its performance is superior to the existing reservation protocols, especially in the integrated traffic scenario. Moreover, the soft capacity feature is exhibited when the traffic load increases.