AES的结构及其S-box分析

分析了AES的加解密原理和密钥生成器的结构，S－box的分布特性。指出了AES与其密钥生成器之间存在一种结构上的同步性，这种同步性可能成为AES的弱点；AES的S－box具有短周期，不具有良好的分布特性。这给AES的密码分析提供了可能，也许会成为AES的致命弱点。     

Dynamic behavior of the He II-He I phase transition under gravity

The phase transition of superfluid helium (He II) to normal fluid helium (He I) is studied in this note. The He II -He I interface is found to move upwards under finite heat current. The temperature tracks are measured by four high resolution temperature sensors (HRTs). And the shifting of the λ　point temperature (phase transition temperature) along the cell is studied experimentally and theoretically. Under gravity, the shifting of the λ point temperature in creases with the pressure. The experimental results agree well with the theoretical ones.     

Isolation and mutation rate of the spontaneous PUR box and purR mutants

In our previous research in purine metabolism in Salmonella typhimurium, it was observed that the mutation frequency of the PUR box was one order of magnitude higher than that of purR under mutagenesis. In order to investigate further into this phenomenon, large amounts of independent PUR box and purR spontaneous mutants were isolated on lactose minimal medium by using a super-repressing mutant of purR (purRs). The mutational regions of 5 PUR box mutants and 4 purR mutants were cloned. Nucleotide sequence analysis showed that all the mutants had mutations at the expected sites. The comparison of the two types of mutations indicated that, although the purR gene was two orders of magnitude larger than the box). Thus, we concluded that high mutation frequency of the PUR box did not result from mutagenesis. Under spontaneous conditions, the mutation frequency of PUR box was also high. Some tentative explanations of this interesting phenomenon are given in this report.     

过渡金属离子对八元瓜环溶解性的影响

实验结果表明过渡金属离子对八元瓜环的溶解性有影响。在测试浓度范围里，随着过渡金属离子溶液浓度的增加，八元瓜环的溶解度逐渐降低。通过原子吸收光谱法测定表明八元瓜环单晶中含有金属离子，但是晶体结构测定仅找到八元瓜环的结构，尚未发现八元瓜环与过渡金属离子形成自组装结构。     

用于多维函数优化的蚁群算法

在借鉴献[1]基本思想的基础上，改进了蚁群算法搜索策略，该策略能提高搜索过程的效率以及搜索状态的多样性和随机性，为蚁群算法应用于实际优化问题提供了一条可行途径，数值算例结果表明本的搜索策略能较好地找到近似全局最优解，是一种有效的近似方法。     

AES的S-盒中仿射变换的性质

美国新一代数据加密标准AES的S-盒由有限域GF(2＾8)中的一个“倒数变换”和环Z2[X]／(x^8 1)中的“仿射变换”复合而成，它们的性质在本质上反映了AES的安全性。而“倒数变换”和“仿射变换”的分布性质是S-盒分布性质的基础。研究了仿射变换的迭代性质，结果表明，AES选取的仿射变换并不具有最好的迭代性质。     

钢筋混凝土箱梁非线性有限元分析中几种C0型单元的探讨

结合钢筋混凝土薄壁箱形梁模型的试验研究，对钢筋混凝土薄壁箱形梁的非线性有限元分析方法进行了比较研究。对非线性有限元分析研究中比较敏感的影响因素进行了分析，并在此基础上提出了适合于钢筋混凝土箱形薄壁梁的非线性有限元分析模型。     

牙膏纸箱堆码蠕变可靠性研究

通过对牙膏纸箱堆码整体蠕变的实验数据分析，运用可靠性理论，统计出了在一定堆码层数下(模拟压力)，最底层牙膏纸箱所承受的堆码压力与堆码时间之间的可靠性关系。     

Protection of phosphatidylcholine to photosystem Ⅱ membrane during heat treatment

Photosystem Ⅱ membrane was reconstituted with phosphatidylcholine (PC) with different kinds of fatty acyl chains and the protection of PC to photosystem Ⅱ (PS Ⅱ)membrane during heat treatment was investigated using oxygen electrode, variable fluorescence and circular dichroism (CD) spectroscopy. Heat treatment decreased the oxygen evolution rate and the F′v/Fm′ ratio of PS Ⅱ membrane and influenced CD spectra of PS Ⅱ membrane, but PC inhibited the effect of heat treatment on the oxygen evolution rate, the F′v/F′m ratio and CD spectra of PS Ⅱ membrane. The results indicate that PC can protect PS Ⅱ membrane against heat treatment and the alterations in the unsaturated fatty acid extent in PC can cause the changes of the protection ability.     

振幅相干态光场与二能级原子的相互作用及场熵的演化

运用J-C模型研究了二能级原子与振幅相干态光场的相互作用，光场-原子系统内部状态间的跃迁几率和光场场熵的演化．