Solitons and production of defects in flow-aligning nematic liquid crystals under simple shear flow

The production of defects in flow-aligning nematic liquid crystals under simple shear flow is analyzed by linear stability analysis based on Leslie-Ericksen theory. It is pointed out that the equation of motion of the nematic director under simple shear flow conforms to the driven over-damped sine-Gordon equation and has a soliton solution of amplitude π. It has also been shown that the stationary state with the director uniformly oriented at a Leslie angle is only a metastable state and that the potential, which governs the motion of the director, has infinite numbers of stable stationary states. Therefore, the defects, appearing as a stable solitary solution, can be nucleated from a uniformly aligned flow-aligning type of nematic liquid crystal by shear flow. On the other hand, the bands with long axis parallel to the vorticity axis, appearing as an unstable solution, can be observed as transient patterns at low shear rate and low shear strain value. The theoretical predictions are compared with previous experimental observations.     

台架系统模糊PID控制算法的研究

船舶减摇水舱试验台架是设计减摇水舱的重要设备，能否准确地模拟船舶在海浪中的运动是设计试验台架的关键，本系统在电液力矩伺服控制系统的基础上加入了Fuzzy—PID环节，使系统的动态性能得到了改善，可控性得到了加强，其仿真结果符合系统设计要求．     

退火对Ni74Si10B16非晶合金电阻温度特性的影响

采用DC四端电阻测试法，测试了不同退火条件下Ni74Sil0B16非晶合金223～423K温区的电阻温度特性曲线，发现：淬态与退火态非晶合金试样的电阻均随温度近线性变化，并且，随着退火时间的延长或退火温度的升高，非晶合金电阻温度系数α上升，而室温电阻率ρ0下降，基于Nagel推广的液态金属Ziman理论，本文对此结果进行了分析和讨论。     

液体火箭洗井器设计原理

根据火箭液体推进剂释放能量高、气化量大的特点，设计出一种新型、高效、快速的水井洗井器，并对其洗井原理、洗井效果、液体推进剂火箭性能等方面进行了分析和经济评估。该洗井器可以提高洗井效率和缩短施工周期，在地下水、油气等资源开发利用方面有重要的应用价值。     

高效液相色谱法测定胃可安胶囊中甘草酸含量

采用高效液相色谱法，对制剂中甘草所含甘草酸的含量测定进行了研究。实验结果表明，本法快速、简便、回收率高，结果准确可靠。     

New approach for screening anti—tumor compounds

A new screening approach for anticancer active compounds is presented.In this method,a target enzyme is incubated with a mixture of compounds,and then the com-plex formed by the target and small molecules is separated from the rest of the mixture by ultra-filtration.The complex that is retained on the membrane is subsequently washed with acid and small molecules that are specifically bound to the target are released and collected,then analyzed by high-performance liquid chromatograph combined with electrospray ionization mass spectrometry (HPLC/ESI-MS) analysis.We have successfully applied this method to screen anti-cancer compounds.DNA topoisomerase Ⅱ is used as a target to capture anti-tumor candidates from a mixture of combinatorial compounds,such as doxorubicin,daunorubi-cin and pravastain.     

催化氧化 -混凝组合工艺处理造纸黄液研究(I)

草浆造纸黑液经酸析分离木质素后 ,废水中的 COD仍高达 80 0 0～ 1 2 0 0 0 mg·L- 1 .以生化过程为末端处理工艺时 ,要达到一级、二级和三级排放标准 ,其中有机物的去除率应分别为 60 .0 %、3 0 .0 %及0 .0 % .最佳处理方案为 Fenton试剂 +Ca(OH) 2 混凝组合工艺 ,此时双氧水的加入量为 0 .75 g· L- 1 .由于该废水中甘露醇等对羟基自由基的猝灭作用 ,从而使得双氧水的氧化效率很低 .     

十六烷基三甲基溴化铵作为气相色谱 固定液的研究与应用

使用工业表面活性剂十六烷基三甲基溴化铵精制后作为气相色谱固定液，测定了它的最高使用温度和相对极性，考察了对一些混合物中各组分分离效果，实验结果说明了精制过程合理，固定液性能良好，令人满意。     

5-溴-2-甲基-吡啶和3-溴-2-甲基-吡啶的分离和制备

以无定型硅胶为填料的自填装柱作为制备柱,借助高效液相色谱泵作为流动相输入的动力,高效液相色谱的紫外检测器作为制备的检测器,探索柱层析分离制备5-溴-2-甲基-吡啶与3-溴-2-甲基-吡啶的实验室小试条件.并用制备的纯品配置溶液得到了标准曲线.     

一类具有光学活性胆甾液晶聚合物的合成与表征

介晶单体十一烯酸胆甾醇酯(M1)和非介晶手性单体十一烯酸薄荷醇酯(M2)通过接枝共聚引入聚甲基含氢硅氧烷(PMHS)中,制得系列侧链液晶聚合物P0～P8·通过傅立叶转换红外光谱(FT-IR)、差示扫描量热仪(DSC)、热失重分析(TGA)、偏光显微镜(POM)、X射线衍射分析(WAXD,SAXS)等手段对聚合物的结构、热致液晶性能及热性能进行了表征·聚合物P0～P8均为胆甾型热致液晶,具有较宽的介晶相范围,呈现出典型的胆甾液晶彩色Grandjean织构及油丝织构,但其液晶性能在非介晶的手性单体M2质量分数大于30%时开始变弱·聚合物都具有较高的热稳定...