MCP机制下考虑供需弹性的发电容量持留

统一出清的定价机制是电力市场中发电商存在持留行为的根本原因。针对电力市场设计中应考虑供需弹性的积极作用,该文分析了拥有边际机组的单个发电商容量持留行为发生的条件及其影响因素,并提出了将持留前后的购电费用之比作为衡量系统持留严重程度的指标W,算例验证,证明供需弹性可以作为制约发电商利用容量持留哄抬电价、危及市场稳定性的有力工具之一。     

On the strength of polycrystalline tungsten monocarbide

The paper consists of analytical and applied parts. The mathematical means of mechanics of hexagonal polycrystals are used in the former. Here the correspondence of the published data on single crystal elastic constants of tungsten monocarbide to elasticity moduli of polycrystalline WC has been analyzed. The relationship between ultimate tensile stress and ultimate compressive stress of polycrystalline tungsten monocarbide has been established too. The dependence of ultimate tensile stress and ultimate compressive stress of polycrystalline tungsten monocarbide on mean grain diameter is considered in the applied part. Here the available experimental data are used.     

Research on forecasting model of sandstone deformation rate during sine wave loading segment under the lag effect

To reduce data variance caused by individual differences of different samples,a new experimental method is proposed by loading and unloading the axial forces with different frequencies and different waves of a certain load amplitude to the same rock sample without damaging it.Lag time segments are defined and fractionized into segments I and Ⅱ.Criterions for seg-mentation,definitions of relevant parameters and empirical analysis are also offered afterwards.In the course of sinusoidal loading,the serious pea...     

血管回声跟踪技术评价糖尿病患者颈动脉弹性与下肢动脉粥样硬化的相关性

目的：利用血管回声跟踪技术（ET）研究糖尿病（DM）患者颈动脉弹性与下肢动脉粥样硬化病变的相关性。方法：选择116例糖尿病患者分别进行颈动脉弹性检查和下肢血管彩超检查,根据血管彩超检查结果分为无下肢动脉粥样硬化病变组（对照组A）和下肢动脉粥样硬化病变组,下肢动脉粥样硬化病变组又根据下肢动脉血管的狭窄程度由轻至重依次分为B、C、D、E四组。分析比较各组间应用髓检查获得的颈动脉弹性参数,即压力应变弹性系数（Ep）、僵硬度（β）、顺应性（AC）、增大指数（AI）、脉冲波传导速度（PWVβ）。结果：下肢动脉粥样硬化病变组Ep取PWvp值较对照组明显增高,Ac值较对照组明显降低,差异有统计学意义（P〈0．01或P〈0．05）,随着各组间下肢动脉病变程度的不断加重,Ep取Pw邯值增加明显,差异有统计学意义（P〈0．01或P〈0．05）,参数AI在各组间差异无统计学意义（P〉0．05）。结论：血管回声跟踪技术能揭示糖尿病患者颈动脉弹性参数与下肢动脉粥样硬化病变程度的相关性,是评价糖尿病下肢动脉粥样硬化病变的有效方法。     

裂纹转子的实验研究

对刚支裂纹转子、具有弹性支承的裂纹转子、刚支无裂纹转子以及具有弹性支承的无裂纹转子的振动特性进行了实验研究。研究表明：刚支裂纹转子和具有弹性支承的裂纹转子均发生分数次共振现象,且增加支承弹性有助于减小谐波共振。     

纵向变形协调时纤维增强复合材料的横向模量分析

近些年来,复合材料横向模量的分析受到了普遍的重视,并获得一定进展.本文采用Phillips提出的串联/并联模型,考虑到沿纵向纤维与基体的变形协调,利用材料力学方法,求得具有正方形截面的纤维增强复合材料的横向模量,进而讨论了其它形状纤维截面的应用.     

Performance Analysis of the Spectral Correlation Discriminator Array

Mobile communications suffer from cochannel interference, adjacent channel interference and fading. The cell capacity or the number of users per cell is limited by the interference. In this paper we analyze a new blind adaptive array structure called the spectral correlation discriminator array (SCDA), designed to reject cochannel interference for advanced mobile phone service (AMPS) signals. The blind adaptive array exploits the spectral redundancy in the AMPS signals which arises due to the presence of the supervisory audio tone (SAT). SCDA is shown to provide an improvement of 25–30 dB in signal-to-interference plus noise ratio (SINR) in static multipath channels and 10–15 dB improvement of SINR in Rayleigh fading channels. The SCDA is compared to the least squares constant modulus array (LSCMA) and is shown to have better signal selectivity properties. The reduction in interference power can significantly reduce the frequency reuse factor.     

不同细观力学方法预测高聚物粘结炸药有效模量的比较

高聚物粘结炸药（PBX）不同于普通颗粒增强复合材料,其颗粒含量超过85%,组分弹性模量相差3~4个数量级,导致其有效模量的细观力学理论预测出现很大偏差。结合有限元细观模拟,对Mori-Tanaka法、自洽法、微分法3种细观力学方法的预测结果进行了比较分析。结果表明：界限法上下界之间有量级上的差异;当颗粒含量小于10%,颗粒间相互作用较小,不同方法计算的有效模量差异不大;含量大于20%时,颗粒间相互作用增强,3种解析法预测的结果逐渐出现差异,而微分法与有限元结果比较接近;当颗粒含量为94.9%,微分法预测的PBX杨氏模量比实测值高3.7%,Mori-Tanaka法和自洽法结果都有量级上的偏差;对于颗粒含量高、组分性能反差大的复合材料,微分法较合理地计及了颗粒间的相互作用,能较准确地预测其有效模量。     

Theoretical study of mechanical properties of multi-layer ULSI interconnect dielectrics by surface acoustic wave method

The surface acoustic waves (SAWs) technique is becoming an attractive tool for accurately and nondestructively characterizing the mechanical property of the fragile low dielectric constant (low-k) thin film used in the advanced ULSI multi-layer interconnects. The dispersion features of SAWs propagating on the layered structure of low-k/SiO₂/Si substrate and low-k/Cu/Si substrate are investigated in detail. The influence of the film thickness on the dispersion curvature is provided as an instruction for an accurate and facile fitting process. Numerical results indicate that the mechanical property of low-k films is expected to determine effectively when the broadband frequency is up to 300 MHz.     

改善经编复合灯箱布横向模量的研究

分析了导致经编复合灯箱布的衬纬纱屈曲的原因,通过改变骨架织物结构和与ＰＶＣ热粘合过程提高灯箱布的横向模量,从而改善国产灯箱布的使用质量。