超高强度钢CF裂纹扩展的超载效应 Ⅰ．定量模型及预测

将Ｗｉｌｌｅｎｂｏｒｇ的超载残余应力场模型与裂尖形变动力学、裂尖表面析氢反应电化学动力学以及裂尖材料内部氢的扩散动力学和热力学相结合，建立了氢脆腐蚀疲劳裂纹扩展（ＣＦＣＧ）超载效应的定量描述模型，给出了超载对裂尖表面析氢电化学反应及裂尖氢扩展影响的一系列判据和表达式．用上述模型进行的预测表明，对于超高强度钢，当两次超载周次之间裂纹扩展长度ａｄ远小于超载塑性区尺寸ｒｐＯＬ与恒载塑性区尺寸ｒｐＣＬＡ之差，即ａｄ＜＜ｒｐＯＬ－ｒｐＣＬＡ时，ＣＦＣＧ会发生比空气疲劳还强烈的超载迟滞效应．而当ａｄ＞ｒｐＯＬ－ｒｐＣＬＡ时，可能会发生超载加速效应．这种预测在后文中由试验的宏观规律与断口特征得到充分验证．     

256比特的混沌分组密码

由于密码分析研究的进展及DES自身的弱点,原64比特的DES将不能作为数据加密的标准算法而长期存在。在原来工作的基础上,本文提出了256比特的分组密码方案。密码算法由基于混沌映射的数字滤波器构造。     

06NiCuCrMoNb钢高温加热时表层铜的行为

将06NiCuCrMoNb钢试样在不同的加热温度保温不同时间后，观察并分析试样表层的形貌和成分。结果表明，在一定条件下铜会扩散进入表层奥氏体晶界，得到沿奥氏体晶界分布的富铜相，并在热变形加工时导致热脆。试验得到了沿奥氏体晶界分布的富铜相与加热温度和保温时间的关系。     

多层气敏薄膜表面吸附及界面扩散的研究

制备了ＳｎＯ３／ＺｎＯ及ＺｎＯ／ＳｎＯ３多层结构的气敏薄膜，用能谱结合氩离子刻蚀的方法及Ｘ射线衍射法，对薄膜的表面吸附。膜间的相互与组成等进行了研究，结果表明：薄膜表面存在少量的吸附多层膜中锌的扩散远比锡一个模型，对吸附现象作了初步的解释，讨论了造成锌锡扩散的原因。     

Electrochemical properties of ultra-long,aligned, carbon nanotube array electrode in organic electrolyte

The electrochemical properties of an electrochemical double-layer capacitor electrode based on an ultra-long (500 μm), aligned, carbon nanotube array (ACNTA) in Et₄NPF₆/propylene carbonate electrolyte are examined. The specific capacitance of the ACNTA electrode in an organic electrolyte is 24.5 F g⁻¹, which is larger than that obtained in an aqueous electrolyte. The results of ac impedance measurements show that the ACNTA electrode gives a high power density and an excellent rate capability in an organic electrolyte. It is shown that the ACNTA electrode has a lower equivalent series resistance and a better rate capability than activated carbon electrode. This is due to the fact that ACNTA possesses a larger pore size and a more a regular pore structure. Both these features are conformed by scanning electron microscopic and nitrogen gas adsorption studies.     

Drying of Chestnuts (Castanea sativa Mill.) after Osmotic Dehydration with Sucrose and Glucose Solutions

Chestnuts were dehydrated by using a combined method of osmotic dehydration followed by air drying. Samples were osmotically pretreated with sucrose (60% w/w) and glucose (56% w/w) for 8 h, air-dried at temperatures of 45, 55, and 65°C, at a relative humidity of 30% and at a velocity of 2.7 m·s^-1 and the experimental data of the drying kinetics were obtained. Whole samples were dried with different peelings: (a) removal of endocarp and pericarp (peeled) and (b) additionally the internal rough surface (cut). In all cases, cut chestnuts show greater drying rates than peeled samples, indicating that a significant mass transfer resistance in the layer nearest to the surface takes place. Peeled samples pretreated with sucrose solutions behave in a similar way to untreated samples. For the rest of the samples, the cut samples osmotically treated with sucrose solutions and all the samples treated with the glucose solution, the drying rates decrease during drying. Drying kinetics are successfully modeled by employing a diffusional model that takes the shrinkage into account. The effective coefficient of water diffusion was evaluated and correlated with temperature. The quality of the final product was monitored by color change. In spite of the fact that the total color difference is not modified by the osmotic treatment, the L*, a*, and b* color coordinates of cut samples treated with sucrose and glucose solutions do undergo changes; the L* and a* coordinates change less than the b*.     

Molecular Diffusion Coefficients of Organic Compounds in Water at Different Temperatures

Molecular (or tracer) diffusion coefficient data were obtained for 2-naphthol, benzoic acid, salicylic acid, camphor, and cinnamic acid in water at temperatures that differ significantly from ambient value. Experimental values were determined for the dissolution of 2-naphthol in water at 283 to 368 K, of benzoic acid in water at 283 to 338 K, of salicylic acid in water at 283 to 343 K, of camphor in water at 283 to 318 K, and of cinnamic acid in water at 283 to 318 K. Empirical correlations are presented for the prediction of molecular diffusion coefficient over the entire range of temperatures studied, and they are shown to predict the obtained data with very good accuracy.     

Determination of Lateral Extension of Hydrocarbon Concentration Sealing Caprocks by AVO Analysis

The caprock is one of the key factors for a reservoir, especially for a gas reservoir. Whether the caprocks can block off the gas is of significance for the accumulation and preservation of the gas reservoir. In this paper, we use the Amplitude versus offset (AVO) seismic technique to determine the lateral extension of the hydrocarbon concentration sealing caprocks. The essence of this technique is to detect the variations of the reservoir bed physical properties by monitoring the variations of the reflection coefficient of seismic waves upon the interfaces between different lithologies.Generally it is used to indicate hydrocarbon directly. For the hydrocarbon concentration sealing caprocks, the change of hydrocarbon concentration may cause the change of physical properties of the caprocks. Therefore it is possible to evaluate the hydrocarbon concentration sealing ability of the caprocks by AVO. This paper presents a case study using AVO to determine the lateral extension of the hydrocarbon concentration sealing caprocks. The result shows that this method is helpful for the exploration of the region.     

程控电话交换机过电流保护元件用高性能PTC陶瓷的研制

阐述了高性能ＰＴＣ陶瓷材料制备的基本要点，并以基方固溶体化学组成、原材料选择、复合添加物改性以及特定烧结工艺等方面开展工作，制得了居里温度为９０℃左右、室温体积电阻率为３０Ω·ｃｍ，电阻率突变ρνｍａｘ／ρνｍｉｎ＞１０５、电阻率温度系数α≈１５％／℃、耐电压强度≥１５０Ｖ／ｍｍ的高性能ＰＴＣ陶瓷材料。此材料制得的元件能满足程控电话交换机过电流保护的要求。     

焊前处理方式对LF6铝合金扩散焊的影响

利用Ｇｌｅｅｂｌｅ－１５００热／力模拟试验机，研究了ＬＦ６铝合金的扩散焊工艺，通过对焊接温度、压力、时间的调整和选用不同的料前处理方法，确定了最佳的扩散规范，研究结果表明：在一定的温度和时间范围内，ＬＦ６５铝合金扩散焊接头的剪切哟度随焊接温度和时间的增加而提高；化学浸蚀法比机械打磨法能更有效的去除铝合金表面的氧化膜；在现有试验条件下，得到ＬＦ６铝合金扩散焊的最佳规范参数，搭接试扩散焊接头的剪切强度