KDP/DKDP晶体生长的研究进展

采用传统降温法,KDP晶体的生长速度一般在1～2 mm/d,DKDP晶体的生长速度甚至更慢,并且晶体的恢复区域较大,利用率低;而采用快速生长法,晶体的生长速度可以提高到20～50 mm/d,并且晶体的恢复区域小,利用率高.本文回顾了KDP/DKDP晶体生长的研究进展.并重点评述了KDP/DKDP晶体快速生长的研究进展,报道了近年来大尺寸、高质量KDP晶体的研究动态.     

几种烟煤及其热处理后的溶胀性能研究

研究了四种不同变质程度烟煤及其二硫化碳/N-甲基-2-吡咯烷酮（CS2/NMP）混合溶剂(1∶1,vol)的抽提物在不同溶剂中的溶胀性能,同时考察了四种煤样不同温度热处理后其溶胀性能的变化。结果表明,煤的溶胀率随煤化度增加而有所降低;变质程度较低的烟煤在极性溶剂中的溶胀率大于非极性溶剂,随着煤化度的增加,两者溶胀度差距减小;四种烟煤经混合溶剂抽提后,其抽余煤的交联密度降低,溶胀率增加。四种煤样150℃热处理后在CS2中的溶胀率均有所增加,表明热处理可以降低煤的交联密度。随着热处理温度提高至240℃,除气煤外,其余三种煤样在NMP和CS2中溶胀率均进一步增大,说明其交联密度进一步降低。这一结果与热处理煤样在混合溶剂中抽提率的变化趋势一致,如240℃热处理后瘦煤的抽提率由原煤的6.9%提高到17.3%。红外光谱研究表明,经过适当温度的热处理,可以脱除煤分子中的羰基和羟基等含氧官能团,破坏煤结构中的氢键,从而降低煤的交联密度,提高煤的溶胀率及其在混合溶剂中的抽提率。     

微波辐射条件下混合溶剂体系中AlPO4-5分子筛的晶貌控制

在微波辐射条件下于混合溶剂体系中实现了AlPO4-5分子筛晶体的形貌控制. 实验结果表明, AlPO4-5分子筛晶体的长径比(c/a)随体系中乙二醇与水体积比的增大而减小, 其长径比可以在1.7~6.3之间调变. 当在体系中加入晶种诱导时, 产物晶粒的大小随加入晶种量的增加和诱导时间的延长而明显减小. 在正丁醇与水的混合体系中, 当正丁醇与水的体积比达到5∶1时, 可以形成哑铃形的特殊晶貌.     

Theoretical Study on the Conformational Conversion of 1,3-Dioxane Inside a Capsular Host

The mechanism for the conformational conversion of 1,3-dioxane guest encapsulated inside a capsular host was theoretically investigated using semiempirical PM3 method and DFT methods. The free-state process of the conformational conversion of 1,3-dioxane was also investigated to make a comparison between the two different states using the same theory. The influences of the inner phase of the capsule on the conformational conversion of guest molecule were discussed via analyzing the comparative results. It was found that the capsular host could accommodate 1,3-dioxane within its cavity by the weak attractive interactions between host and guest, and it responds to the conformational conversion of guest by the deformation of hydrogen-bonding seam at the middle of the capsule. When entrapped in the capsule, the guest molecule undergoes the conformational conversion from chair form to twist-boat form slower than that under the free condition. The deformation of the capsule is favorable to maximize the attractive interactions between host and guest.     

Cloning, Expression and Purification of Wheat Acetyl-CoA Carboxylases CT Domain in E.coil

The entire gene of carboxyltransferase(CT) domain of acetyl-CoA carboxylase(ACCase) from Chinese Spring wheat(CSW) plastid was cloned firstly,and the 2.3 kb gene was inserted into PET28a+ vector and expressed in E.coil in a soluble state.The (His)6 fusion protein was identified by SDS-PAGE and Western blot.The recombinant protein was purified by affinity chromatography,and the calculated molecular mass(Mr) was 88000.The results of the sequence analysis indicate that the cloned gene(GeneBank accession No.EU124675) was a supplement and revision of the reported ACCase CT partial cDNA from Chinese Spring wheat plastid.The recombinant protein will be significant for us to investigate the recognizing mechanism between ACCase and herbicides,and further to screen new herbicides.     

Electrochemical Oxidation of Ammonia on Ir Anode in Potential Fixed Electrochemical Sensor

Ir catalyst possesses a good electrocatalytic activity and selectivity for the oxidation of NH3 and/or NH4OH at Ir anode in the potential fixed electrochemical sensor with the neutral solution. Owing to the same electrochemical behavior of NH3 and NH4OH in a NaClO4 solution, NH4OH can be used instead of NH3 for the experimental convenience. It was found that the potential of the oxidation peak of NH4OH at the Ir/GC electrode in NaClO4 solutions is at about 0.85 V, and the current density of the oxidation peak of NH4OH is linearly proportional to the concentration of NHaOH. The electrocatalytic oxidation of NH4OH is diffusion-controlled. Especially, Ir has no electrocatalytic activity for the CO oxidation, illustrating that CO does not interfere in the measurement of NH4OH and the potential fixed electrochemical NH3 sensor with the neutral solution, and the anodic Ir catalyst possesses a good selectivity. Therefore, Ir may have practical application in the potential fixed electrochemical NH3 sensor with the neutral solution.     

pH 响应P(AM-co-AA)/PAAC 半互穿网络微凝胶的合成及表征

在反相微乳液体系中,合成了 pH 响应的聚丙烯酰胺(AM)-丙烯酸(AA)/聚烯丙基氯化铵(PAAC)半互穿网络(semi-IPN-P(AM-co-AA)/PAAC)微凝胶.采用 TEM、光散射及 Zeta电位对微凝胶的微观形貌及 pH 的响应行为进行测定,考察离子强度对微凝胶粒径的影响.结果表明:微凝胶的粒径约 80 nm,溶胀行为对pH及离子强度敏感,改变PAAC的含量可以得到不同PH 下响应的微凝胶.     

多条形电极束流能散度探测器的张角优化

 采用Surperfish对北京正负电子对撞机的多条形电极束流能散度探测器进行了电磁场模拟计算。在带模拟束流的情况下,计算分析了探测器对束流位置和能散度的分辨能力与电极张角之间的关系,首次计算了条形电极间的电容耦合综合强度。电极张角优化结果表明：在不考虑噪声水平的情况下,电极张角为20°时,探测器的灵敏度和分辨率达到最优。而当噪声影响很大时,可以适当增加电极张角,同时考虑减小噪声的措施。     

荧光猝灭法对肉桂酸与人血清白蛋白间的相互作用的研究

白蛋白是血液循环系统中最丰富的一种蛋白质,能与许多物质结合,并起着运输蛋白的作用。文章利用荧光光谱法研究了中药有效成分肉桂酸与人血清蛋白间的非共价结合特性。研究表明,在pH7.4作用液、286nm激发波长条件下,肉桂酸对人血清白蛋白的荧光发射有较强猝灭作用。当作用温度为37和47℃时,肉桂酸与人血清蛋白间的结合常数K分别为1.2767×103和3.4041×103L.mol-1,结合位点数n分别为0.7586和0.8356,表明温度升高有利于两者的结合;同时,根据不同作用温度时非共价结合复合物的热力学参数变化,证明肉桂酸与人血清白蛋白分子间的结合力主要是疏水作用。研究结果为进一步研究肉桂酸的药理作用,尤其是对血浆蛋白构像的影响提供了重要信息。     

直接解调方法在嫦娥一号卫星X射线谱仪地面验证实验数据分析中的应用

"嫦娥一号"卫星是我国的第一颗月球探测卫星,运行轨道高度为200 km,预计工作寿命为一年,其上配备的X射线成像谱仪具备了对月表进行X射线探测、成像和对太阳X射线进行监测的功能.该X射线谱仪由两个全同的探测器阵列组成,其中,为了实现对月表主要化学元素分布及其含量进行探测的科学目标,在每个探测器阵列还配备了2个低能探测器单元.这4路低能探测器单元的面积为25 mm2,采用的都是厚度为500 μm,具有优良探测性能的Si-PIN探测器,其探测能区为1～10 keV,能量分辨率为～5%@5.9 kev.文章主要介绍了嫦娥一号卫星X射线谱仪的地面验证实验,并且根据X射线谱仪的能量响应矩阵,利用直接解调方法和基本参数法对X射线谱仪地面验证实验中的探测数据,特别是对盲测样品中的Mg,Al,Si等元素进行了定性和定量分析.