无模板剂二次生长法制备取向MFI型分子筛膜

使用旋涂法在多孔α-Al₂O₃载体上获得了b-&h0h-取向的silicalite-1晶种层。在无模板剂存在条件下进行二次生长,通过改变合成液的碱度(OH^-/Si)、水量(H₂O/Si)和晶化温度等,调节膜表面的形貌和晶体取向。SEM和XRD检测结果表明,对于1SiO₂:4EtOH∶xNaOH∶yH₂O合成体系,x与y值的选取与分子筛膜的形貌和晶体取向紧密相关。当x=0.56时,增加y值将促进分子筛膜从随机取向到b-轴取向的转变,晶粒形貌也发生了较大变化;当y=270时,可以得到厚约为4 μm、连续且择优b-轴取向的MFI型分子筛膜。     

Crystallization of silicalite‐1 from clear synthesis solutions: Effect of template concentration on crystallization rate and crystal size

Synthesis of silicalite‐1 powders and membranes from initially clear solutions with different tetrapropylammonium hydroxide or bromide concentrations was studied. While tetrapropylammonium bromide acts only as template, tetrapropylammonium hydroxide provides both the template and hydroxyl ions to the synthesis medium. The effects of template and hydroxyl ion concentration on the product yield, crystallization rate and crystal size were investigated. Pure and highly crystalline silicalite‐1 was obtained with all compositions. The nucleation time decreases from 100 h to 20 h and the crystal size decreases from 3.5 μm to 0.35 μm as the template amount x is increased from 5 to 30 moles at a batch composition of 80SiO₂.xTPAOH.1500H₂O at 95 °C. Yield of silicalite‐1 passes through a maximum at intermediate TPA concentration. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

第四届全国周培源大学生力学竞赛理论力学试题

讨论了对于纵横交错的城市道路,不一定越宽越好．还讨论了,在这种道路上,使行驶的车辆只停一次红灯的策略．这种策略和城市道路的布置、车辆的限速、红绿灯的持续时间是有关的．     

用平均场近似研究液晶分子结构与清亮点的关系

液晶的平均场理论假设每个液晶分子都是处在其它周围所有分子的平均作用势场中, 而不考虑该分子与周围各个分子之间的单独关联, 一个分子所感受到的分子场就是所有其它分子给予这个分子的作用场对位置和对取向的平均值. 当周围分子不是完全有序排列时, 其混乱程度可以用序参量S表示(S≤1), 中央一个分子受的势能为－Sg(θ). 其中g(θ)是在排列整齐的平均场中该分子的势能函数的负值. 在此基础上, 可以解一个关于序参量和温度的积分方程, 求出清亮点. 本文采用Gay-Berne势模拟液晶分子的双体势, 用分子力学UFF方法优化液晶分子(二环辛烷和硼笼的衍生物)的单体和双体的构型和能量, 从而获得Gay-Berne势的参数, 得到液晶的清亮点. 计算结果与实验基本一致.     

Bioinformatics analysis and verification of gene targets for renal clear cell carcinoma

BackgroundIt is estimated that there are 338,000 new renal-cell carcinoma releases every year in the world. Renal cell carcinoma (RCC) is a heterogeneous tumor, of which more than 70% is clear cell renal cell carcinoma (ccRCC). It is estimated that about 30% of new renal-cell carcinoma patients have metastases at the time of diagnosis. However, the pathogenesis of renal clear cell carcinoma has not been elucidated. Therefore, it is necessary to further study the pathogenesis of ccRCC.MethodsTwo expression profiling datasets (GSE68417, GSE71963) were downloaded from the GEO database. Differentially expressed genes (DEGs) between ccRCC and normal tissue samples were identified by GEO2R. Functional enrichment analysis was made by the DAVID tool. Protein-protein interaction (PPI) network was constructed. The hub genes were excavated. The clustering analysis of expression level of hub genes was performed by UCSC (University of California Santa Cruz) Xena database. The hub gene on overall survival rate (OS) in patients with ccRCC was performed by Kaplan-Meier Plotter. Finally, we used the ccRCC renal tissue samples to verify the hub genes.Results1182 common DEGs between the two datasets were identified. The results of GO and KEGG analysis revealed that variations in were predominantly enriched in intracellular signaling cascade, oxidation reduction, intrinsic to membrane, integral to membrane, nucleoside binding, purine nucleoside binding, pathways in cancer, focal adhesion, cell adhesion molecules. 10 hub genes ITGAX, CD86, LY86, TLR2, TYROBP, FCGR2A, FCGR2B, PTPRC, ITGB2, ITGAM were identified. FCGR2B and TYROBP were negatively correlated with the overall survival rate in patients with ccRCC (P < 0.05). RT-qPCR analysis showed that the relative expression levels of CD86, FCGR2A, FCGR2B, TYROBP, LY86, and TLR2 were significantly higher in ccRCC samples, compared with the adjacent renal tissue groups.ConclusionsIn summary, bioinformatics technology could be a useful tool to predict the progression of ccRCC. In addition, there are DEGs between ccRCC tumor tissue and normal renal tissue, and these DEGs might be considered as biomarkers for ccRCC.     

小颗粒NaY分子筛透明液相导向剂的制备及其性能

小颗粒ＮａＹ分子筛透明液相导向剂的制备及其性能马跃龙，陈诵英，彭少逸（中国科学院山西煤炭化学研究所煤转化国家重点实验室，太原０３０００１）关键词ＮａＹ分子筛，制备，常规导向剂，透明液相导向剂，使用寿命，老化时间ＮａＹ分子筛作为催化剂组成部分广泛应用于...     

氧气氧化法制备三氯氧磷的清洁生产工艺

从"提高分散度、增强换热能力和根治泄漏"入手,对氧化法制三氯氧磷的现存工艺进行了有效改造 新工艺生产过程中无三废排放,原材料利用率接近100%     

醋酸综合症对电影胶片影像影响研究

醋酸综合症是醋酸纤维素酯电影胶片特有病害现象，是威胁其安全保存的主要因素。醋酸综合症导致电影胶片的几何尺寸改变、机械强度降低、影像信息严重受损。本文采用基恩士VK-X250K形状分析激光显微镜研究了醋酸综合症电影胶片片基层表面粗糙度；采用X-Rite Model VS450分光光度计研究了其表面对可见光的反射率。实验结果表明胶片发生醋酸综合症之后，其表面粗糙度增大，对可见光的漫反射增强。由此可以说明醋酸综合症发生之后，胶片表面析出的增塑剂形成粗糙界面，对可见光的漫反射增强，在放映过程中透射光减弱，这是胶片记载影像受损的主要因素。     

“离子迁移”实验的改进及其实验条件优化*

针对“离子迁移”实验中实验现象不明显、实验操作难度大的问题。采用将CuSO₄、K₂CrO₄与淀粉加工成热的糊状流体,趁热装入U型管,冷却后变成半固体的方法,解决了上述问题。并采用单因素实验法对淀粉的用量、CuSO₄与K₂CrO₄混合物的用量(CuSO₄与K₂CrO₄物质的量之比为1∶1)以及迁移电压等实验条件进行优化。优化后的实验结果显示,离子迁移后形成的区域颜色与半固体淀粉的颜色差别很大,便于学生远距离识别。该方法操作简单、现象明显,有利于一线教师的教学演示和学生的分组实验。     

Coupling effect of surface plasmon polaritons in single-negative lamellar heterostructure

Propagation characteristics of surface plasmon polaritons (SPPs) in the lamellar heterostructure, which is actually a SPP waveguide array, constructed by two kinds of single negative (SNG) material layers stacked alternatively are investigated. Based on the finite element method (FEM), the negative-refraction (NR) property is demonstrated when the electromagnetic wave penetrates through free space into such SNG lamellar structure. A clear view of the underlying physics of NR is presented qualitatively that is mainly related to the coupled SPPs. The strong coupling effect leads to the novel SPP dispersion curves and then the anomalous propagation characteristics.