Synthesis and characterization of siloxane resins derived from silphenylene‐siloxane copolymers bearing benzocyclobutene pendant groups

Two bis(dimethylamimo)silanes with benzocyclobutene (BCB) groups, bis(dimethylamino)methyl(4′‐benzocyclobutenyl)silane ( 2 ) and bis(dimethylamino)methyl [2′‐(4′‐benzocyclobutenyl)vinyl]silane ( 4 ), were synthesized from different synthetic routes, which were then employed to prepare two novel silphenylene‐siloxane copolymers (SiBu and SiViBu) bearing latent reactive BCB groups by polycondensation procedure with 1,4‐bis(hydroxydimethylsilyl)benzene. At elevated temperatures these copolymers were readily converted to highly crosslinked films and molding disks with network structures by polymer chain crosslinking, which followed the first‐order kinetic reaction model. The final resins of SiBu and SiViBu demonstrated excellent thermal stability with high glass transition temperatures (218 and 256 °C) and high temperatures at 5% weight loss (553 and 526 °C in N₂, 530 and 508 °C in air). After aging at 300 °C in air for 100 h, the cured resins showed weight loss lower than 4%. The films of cured SiBu and SiViBu also exhibited relatively low dielectric constants of 2.66 and 2.64, low dissipation factors of 2.23 and 2.12 × 10^?3, low water absorptions (≤0.28%), and high transparence in the visible region with cutoff wavelengths of 321 and 314 nm. Moreover, the aged films exhibited good dielectric properties and low water absorptions. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7868–7881, 2008     

Co-NH2-SBA-15的制备及其脱硫性能研究

采用水热合成法制备介孔分子筛SBA-15,用（CH₃COO）₂Co对其进行超声浸渍改性,并用硅烷偶联剂APTS将氨基引入SBA-15分子筛中,制备出Co-NH₂-SBA-15吸附剂,考察了常温条件下H₂S的吸附性能。通过SEM、XRD、FT-IR、BET、XPS等表征手段对吸附剂进行表征。结果表明,氨基与金属同时负载在分子筛表面,氨基与硅物质的量比为0.20,Co负载质量分数为8%的SBA-15吸附效果最好,当原料气H₂S体积分数为227 μL/L,温度25 ℃,气体流量75 mL/min时,穿透硫容和饱和硫容达0.151和0.190 mmol/g,且吸附剂可再生利用。SBA-15表面嫁接氨基并浸渍金属改性的手段不仅提高了吸附容量,同时提高了分子筛的稳定性。     

新型酯型反相高效液相色谱填料的制备,表征及性能评价

将一种新型硅烷偶联剂β－（3，4－环氧环己基）乙基三甲氧基硅烷（β－ECTS）与辛酸反应，然后再键合到硅胶上，得到了酯型键合固定相。用元素分析，^13C固体核磁共振谱，红外光谱进行了表征。以甲醇和水为二元流动相，用包括碱性，酸性和中性有机化合物在内的混合物评价该固定相的疏水性，选择性和亲碱醇基效应，并考察了该填料适用的pH范围及水解稳定性，结果表明，该固定相具有较好的色谱性能，且在pH=2.5-7.5之间稳定性良好，可有效地用于碱性化合物的分析分离。     

用数值遗传算法同时求解配合物稳定常数和各型体的纯光谱

用数值遗传算法同时求解配合物稳定常数和各型体的纯光谱张众杰，李通化，朱仲良，丛培盛，孙云平（同济大学化学系，上海，２０００９２）关键词数值遗传算法，二维数据，稳定常数利用滴定或光度法的测定数据，求解酸的离解常数和配合物的稳定常数是化学工作者十分熟悉并...     

两种四苯甲亚胺基酞菁锌(Ⅱ)的合成及其紫外可见光谱的研究

从两种氨基酞菁锌出发，经一步反应，合成出了两种四苯甲亚胺基酞菁锌(Ⅱ)，并对合成的产物进行了质谱、紫外可见光谱、红外光谱表征．对合成产物的紫外可见光谱，从取代基与酞菁(Pc)大环之间的共轭形式、空间位阻效应、溶剂效应等几方面进行了分析，并与相应氨基酞菁化合物的紫外可见光谱进行了比较．发现外围(2，9，16，23位)取代产物2a的取代基R与Pc大环有较强的π-Ⅱ共轭，内围(1，8，15，22)取代产物2b的取代基R与Pc大环有较强的sp^2-Ⅱ共轭．     

具有纳米尺寸的四聚四硫富瓦烯大环冠醚的合成

以二(碘乙基)醚和2,3-二氰乙硫基四硫富瓦烯衍生物作为起始原料, 采用腈乙基保护与脱保护技术, 通过多步反应以较好的收率合成了两个纳米结构的大环四硫富瓦烯冠醚5a～5b. 通过循环伏安法(CV)研究了化合物4b和5b的电化学性质, 并用¹H NMR谱研究了5b与[60]富勒烯之间的相互作用. 结果表明: 5b存在环结构效应, 与[60]富勒烯有一定程度的电荷转移相互作用.     

PETROLOGY OF BLUESCHIST IN WESTERN YUNNAN PROVINCE,CHINA,AND ITS TECTONIC SIGNIFICANCE

The blueschists in western Yunnan Province are distributed in Lancangjiang and Ailaoshan metamorphic belts and occur as interlayer in green schist and mica schist. Their protolith is basaltic and pelitic rocks with a mineral assemblage of Cr (or Win)+Ab+Qz+Chl+Ph+Ep+Sph+Act and Gl+Ph+Tc+Ep+Alm+Qz+Do, respectively. The P-T conditions of blueschist metamorphism range from 170—443℃ at c. 4—6. 7 kbar. The origin of blue schist of the Lancangjiang belt is related to the subduction and the close of the paleo-Tethys oceanic basin. The Ailaoshan blueschist, however, may be related to the continent continent collision and the dynamic metamorphism.     

Accelerating AutoDock Vina with GPUs

AutoDock Vina is one of the most popular molecular docking tools. In the latest benchmark CASF-2016 for comparative assessment of scoring functions, AutoDock Vina won the best docking power among all the docking tools. Modern drug discovery is facing a common scenario of large virtual screening of drug hits from huge compound databases. Due to the seriality characteristic of the AutoDock Vina algorithm, there is no successful report on its parallel acceleration with GPUs. Current acceleration of AutoDock Vina typically relies on the stack of computing power as well as the allocation of resource and tasks, such as the VirtualFlow platform. The vast resource expenditure and the high access threshold of users will greatly limit the popularity of AutoDock Vina and the flexibility of its usage in modern drug discovery. In this work, we proposed a new method, Vina-GPU, for accelerating AutoDock Vina with GPUs, which is greatly needed for reducing the investment for large virtual screens and also for wider application in large-scale virtual screening on personal computers, station servers or cloud computing, etc. Our proposed method is based on a modified Monte Carlo using simulating annealing AI algorithm. It greatly raises the number of initial random conformations and reduces the search depth of each thread. Moreover, a classic optimizer named BFGS is adopted to optimize the ligand conformations during the docking progress, before a heterogeneous OpenCL implementation was developed to realize its parallel acceleration leveraging thousands of GPU cores. Large benchmark tests show that Vina-GPU reaches an average of 21-fold and a maximum of 50-fold docking acceleration against the original AutoDock Vina while ensuring their comparable docking accuracy, indicating its potential for pushing the popularization of AutoDock Vina in large virtual screens.     

高压串级延迟击穿开关在快前沿脉冲触发源中的应用

 报导了一种高压串级延迟击穿（DBD）开关在快脉冲触发源中的应用,介绍了脉冲源的电路结构和工作原理,并将DBD开关成功应用于快前沿脉冲触发源,获得了明显的脉冲陡化效果。串级DBD开关的级数为15级,直流击穿电压45 kV,脉冲工作电压60 kV,脉冲前沿由95 ns减小到21.5 ns,脉冲宽度50 ns。     

Preparation of Copper Phthalocyanine Crystals Using Solvothermal Synthesis

A novel solvothermal synthesis method for the direct growth of B-form crystals of copper phthalocyanine（CuPc） is presented in this article. With quinoline as solvent, crystals were grown after cooling the reaction mixture of 1,3-diiminoisoindoline and copper oxide, heated for 9 h at 270 ℃, to room temperature in an autoclave. These high quality crystals were suitable for characterization measurements. The single-crystal diffraction data show a monoclinic system unit cell： a=1.4668（3） nm, b=0.48109（10） nm, c=1.9515（7） nm, a=90°, B=121.04（2）°, r=90°, where the corresponding cell volume is 1.17991 nm^3. Needle-like single crystals of CuPc up to 10.5 mm in length were obtained. The influences of different temperatures, reaction time and solvent volume on the crystal yields were also discussed. Optimum reaction conditions were 10 mL of quinoline, at 270 ℃ for 8 h.