A creep rupture criterion for Zircaloy-4 fuel cladding under internal pressure

The usual criterion which limits the cladding strain to 0.01 to prevent the creep rupture under internal pressure seems too conservative for application to transport and interim storage. So we have analysed CEA’s data on this subject for CWSR Zircaloy-4 in order to find a less conservative criterion. Temperatures between 350 and 470 °C were studied for stresses between 100 and 550 MPa, according to the irradiation level from 0 to 9.5 × 10²⁵ n m⁻². Except for high stressed irradiated material (because of low ductility), the plastic instability appears as the major mechanism of rupture. For the unirradiated material, it is essentially due to the stress increase with strain. This instability is accelerated by annealing for the irradiated one at moderate or low stress. From these considerations, we propose a new rupture criterion for CWSR Zircaloy-4 cladding submitted to internal pressure, for both unirradiated and irradiated materials.     

High-pressure hydriding of Zircaloy cladding by the thermogravimetry and tube-burst techniques

Hydriding kinetics of modified Zircaloy claddings was studied by the thermogravimetric method at 400 °C and the tube-burst technique at 315 °C. Some specimens were prefilmed with a thin oxide layer by air oxidation on both the inner and outer surfaces which were either pickled or blasted. In the thermogravimetric test, the hydriding rates of bare cladding specimens (no oxide prefilm) were in the range 0.9-1.6 mg/cm² h with little effect of the surface treatment. Incubation times were less than 1 h or even zero. In the tube-burst test, immediate and extensive hydrogen uptake was observed for these non-coated specimens. On the other hand, the cladding specimens with oxide prefilm exhibited lower hydriding rates ranging from 0.01 to 0.05 mg/cm² h and incubation times increased to 42 h. In addition, no hydrogen uptake was observed for all oxide-coated specimens for 100-750 h.     

Simpler Reasoning About System Properties: a Proof-by-Refinement Technique

Proofs about system specifications are difficult to conduct, particularly for large specifications. Using abstraction and refinement, we propose a proof technique that simplifies these proofs. We apply the technique to Circus (a combination of Z and CSP) specifications of different complexities. Interestingly, all the proofs are conducted in Z, even those concerning reactive behaviour.     

毛细管放电激励类氖-氩离子X光激光研究

以类氖 氩离子跃迁线为例 ,应用一维的Lagrangian程序———XDCH研究了毛细管放电碰撞机制激励软X光激光的物理机制 ;对等离子体的Z 箍缩过程和 46 9nm谱线产生增益的条件进行了讨论 ;并分析了毛细管放电装置中产生软X激光的可能性。     

25mm厚钢板产生层间撕裂的原因和防治

层间撕裂并非是厚板独有的质量问题 ,结合工程实例 ,分析 2 5mm厚低合金钢板产生层间撕裂的原因。通过对钢材的超声波探伤检测、化学成分分析和Z向性能检测 ,指出层间撕裂主要与节点设计不当和钢材内非金属夹杂物偏析、分层有关 ,并提出了预防措施。对产生裂纹的构件视严重情况提出了不同的修补处理方法     

探析热电制冷

本文指出热电制冷是2l世纪极有发展前景的制冷新技术，但目前发展水平还不够高。由于制冷系数低、性能价格比较低及对电源要求较高等因素，目前发展受到了制约。新材料、新工艺、新技术及新电源的突破发展，是热电制冷进入一般工业和家庭生活的前提。     

Hydrogen absorption by Pd-coated ZrNi prepared by using Barrel-Sputtering System

To improve the durability of hydrogen storage materials against surface poisoning by impurity gases, effectiveness of Pd-coating layer prepared by using a Barrel-Sputtering System was examined for ZrNi powder. The effectiveness of Pd-coating was evaluated by activation temperature, at which Pd/ZrNi poisoned by air could be activated to absorb hydrogen. Characterization of Pd-coated ZrNi (denoted as Pd/ZrNi) by scanning electron microscopy, electron probe microanalysis and X-ray diffraction showed that a uniform Pd-coating layer was formed with the barrel-sputtering system. It was found that the poisoned Pd/ZrNi sample could be activated even at 423 K to absorb hydrogen at room temperature. This exhibits remarkable contrast to bare ZrNi, which could be only activated appreciably above 1073 K. It is concluded that the Pd-coating by barrel sputtering is quite effective to avoid the effect of surface poisoning of powdery hydrogen storage materials. However, the activation at excessively high temperature resulted in the loss of high activity to absorb hydrogen. It was concluded that this phenomenon was associated with reactions between Pd and ZrNi to form PdZr and other byproducts.     

TFT有源矩阵α－Si∶H薄膜PECVD淀积工艺研究

分析了α－Ｓｉ∶Ｈ薄膜的质量和厚度对α－Ｓｉ∶ＨＴＦＴ关键性指标的影响，深入、详细地讨论了其ＰＥＣＶＤ淀积工艺，并在实验的基础上确定了最佳淀积工艺参数，从而获得了高性能的７５ｍｍ３７２×２７６像素α－Ｓｉ∶ＨＴＦＴ有源矩阵     

一种3V CMOS音乐集成电路的设计原理

介绍了一种数字式全定制音乐集成电路设计原理。对伪音阶发生器、节拍发生器等子电路作了较详细的叙述。采用这种原理可设计出单芯片驱动压电陶瓷和发光二极管的音乐集成电路，该电路无须外接电阻、电容，可存储数首歌曲；另外，还可设计出一种数字音频程控频率合成器，时钟为ｆ０时，可控频率范围为ｆ０２～ｆ０２Ｎ。     

基于Z的协议形式描述与验证

一、引言在过去的十年.计算机网络与分布式系统已取得了很大的进展[6j。步入九十年代,各种新型通信技术和分布式应用已相继出现.并已对计算机通信软件发生了重要影响。这些新技术及应用主要包括高速光纤网、多媒体通信、宽带综合业务数字网(B一IsDN)、智能网络技术.如智能服务器、智能路由选择、智能协议开发环境等.以及综合语音、数据、图文和图象服务等等。为了适应这种形势的发展一门新兴的学科一协议工程已应运而生川。