核电材料在模拟反应堆环境中应力腐蚀破裂测试技术与性能评价

简要介绍了采用慢应变速率试验，Ｕ型弯曲和Ｃ形环试验等技术，分别对８００合金，３０４和３１６及３１６Ｔｉ不锈钢Ａ５３３Ｂ压力容器用多在模拟核反应堆环境中的应力腐蚀破裂敏感性性进行的试验研究的一些主要结果；并结合电化学测试和表面膜俄歇电子能谱分析结果进行了讨论。     

CA／PAN中空纤维血浆分离膜的结构与性能

本研究以CA及PAN的共混溶液,通过干-湿法纺丝制取中空纤维,利用共混高聚物各组分在凝固剂中相分离速度的差异,形成具有稳定结构的中空纤维孔膜,该膜用于分离血液中的血浆成分具有良好效果。讨论了成型条件及添加剂等对膜结构、性能的影响,用SEM及图相分析仪、MAP压汞仪及DSC等分析手段,对膜的微孔结构、形态、孔尺寸及中空纤维膜的血浆通量和水通量等进行了系统的考查。     

隧道挖掘中采用补偿灌浆的实例

在英国伦敦多克兰斯轻便铁路刘易舍姆延长线（DLR－LWE）双隧道掘进工程中，在敏感建筑物下进行了补偿灌浆，以防止隧道开挖引起的过度沉降。但是，过度灌浆也会对隧道下部施加超越。介绍了由隧道掘进承包商所编辑的关于地面和建筑物沉降以及由补偿灌浆引起的隧道衬砌变形的详细现场监测数据。     

A new hybrid active power filter (APF) topology

In this paper, a new hybrid active power filter topology is presented. A higher-voltage, low-switching frequency insulated gate bipolar transistor (IGBT) inverter and a lower-voltage high-switching frequency metal oxide semiconductor field effect transistor (MOSFET) inverter are used in combination to achieve harmonic current compensation. The function of the IGBT inverter is to support utility fundamental voltage and to compensate for the fundamental reactive power. The MOSFET inverter fulfills the function of harmonic current compensation. To further reduce cost and to simplify control, the IGBT and MOSFET inverters share the same DC-link via a split capacitor bank. With this approach harmonics can be cancelled over a wide frequency range. Compared to the conventional APF topology, the proposed approach employs lower dc-link voltage and generates less noise. Simulation and experimental results show that the proposed active power filter topology is capable of compensating for the load harmonics     

Principle and applications of retroreflective vision sensing for discrete part-presentation

For flexible manufacturing of short production runs where a large variety of product sizes, component types, and surface reflectance characteristics are encountered, it is desirable to build flexible computer-controlled systems for feeding parts into machine tools or assembly processes that combine maximum flexibility and reliability with minimum cost and cycle-time. This is not a general bin-picking problem; the parts are assumed to be propositioned approximately in totes/pallets/kits with regularly spaced locations. This article presents a machine vision technique based on the principle of retroreflective vision sensing for part-presentation. Since retroreflective material has a distinctive surface reflectance that is not commonly found in natural or man-made objects, the use of retroreflective surfaces enables reliable high object-to-background contrast images to be obtained for a wide variety of objects. Unlike conventional machine vision techniques, which rely on the variance of the surface reflectance of the objects to generate detailed images, retroreflective vision sensing aims at generating a reliable two-dimensional digital object silhouettes so that the location and orientation of the part can be reliably determined. Two application examples, machine loading and assembly, are illustrated.     

Linewidth and FM characteristics of a distributed feedback laser monolithically integrated with a tunable external cavity

A narrow linewidth has been obtained in a new 1.5 ?m distributed feedback laser integrated monolithically with a tunable external cavity. The linewidth of 18 MHz has been achieved by tuning the current in the external cavity, and the FM response was flat from 100 kHz to 500 MHz.     

Delay-dependent state estimation for delayed neural networks

In this letter, the delay-dependent state estimation problem for neural networks with time-varying delay is investigated. A delay-dependent criterion is established to estimate the neuron states through available output measurements such that the dynamics of the estimation error is globally exponentially stable. The proposed method is based on the free-weighting matrix approach and is applicable to the case that the derivative of a time-varying delay takes any value. An algorithm is presented to compute the state estimator. Finally, a numerical example is given to demonstrate the effectiveness of this approach and the improvement over existing ones.     

新疆伊犁托海水电站拱坝坝体变形监测分析

根据托海拱坝5号坝段、7号坝段例垂线实测资料分析，说明了新疆寒冷地区坝体采取聚胺脂喷涂施工措施后对坝体变形的影响，以及右坝肩渗漏对右坝肩岩体的影响，分析结果为托海水电站通过国家电力公司大坝安全监察中心大坝安全首次定检提供了科学依据。     

Motivations for the San Fernando Valley Secession Movement: The Political Dynamics of Secession

I argue that the motivation for the San Fernando Valley secession movement can be explained as a desire for local control based on democratic ideals, but I emphasize that the movement is also motivated in part by the tangible benefits that accompany such autonomy. After a brief look at possible economic and racial motivations behind the secession movement, I look for a political divide between the city and the Valley, based on literature that has found political divisions between urban and suburban areas. Evidence of a political divide is mixed, but does indicate that the Valley lacks representation in comparison to the rest of the city. Valley residents may also fear increasing minority political power, which could erode the dominance of Valley whites at the polls. There is also evidence that those who favor secession are most dissatisfied with representation and most concerned with getting their fair share of services from the city, indicating a strong desire for more local control. Images of a smaller, more democratic government, and a more engaged local civic community are prime motivations in the Valley’s quest for autonomy, though the possibility of reduced taxes, land use control, and increased political power do offer secessionists clear substantive benefits in addition to more democratic goals.     

Chemical leaching and magnetic properties of non-equilibrium Al(Co–Cu) powders produced by rod milling

We report upon the chemical leaching and magnetic properties of nanoscale crystalline Al_0.6(Co₂₅Cu₇₅)_0.4 alloy powders produced by rod milling. X-Ray diffractometry (XRD), transmission electron microscopy, differential scanning calorimetry, vibrating sample magnetometry, and superconducting quantum interference device magnetometry were used to characterize the as-milled and leached specimens. After 400 h of milling, only the b.c.c. phase of the intermetallic compound γ-Al_3.892Cu_6.10808 was detected by XRD. After annealing the leached specimen at 600 °C for 1 h, the nanoscale crystalline phase was transformed into the f.c.c. Cu phase, and this was accompanied by a change in the magnetic properties. The peaks of the magnetization shifted towards lower temperature with increasing external field. The temperature behavior at T_f (45 K) for direct current (d.c.) magnetic susceptibility measurements was quite different for field cooling and zero-field cooling. After cooling the leached specimen from 800 °C, magnetization increased gradually.