超支化双吡啶亚胺铬催化剂的合成及催化乙烯齐聚性能

以1.0代(G)超支化大分子(C₃₈H₅₁N₉O₂)为配体骨架,2-氯-4-甲基吡啶和CrCl₃(THF)₃为原料,依次经过取代和配合反应合成了一种超支化双吡啶亚胺配体及其铬催化剂。 利用紫外-可见光谱(UV-Vis)、傅里叶变换红外光谱(FT-IR)、电喷雾电离质谱(ESI-MS)、核磁共振氢谱(¹H NMR)和元素分析等方法对其进行表征。 结果与理论设计预期一致。 考察了反应温度、乙烯压力、Al与Cr摩尔比(n(Al)/n(Cr))、溶剂及助催化剂种类等因素对催化剂催化乙烯齐聚性能的影响。 结果表明,以甲苯为溶剂,甲基铝氧烷(MAO)为助催化剂,当反应温度为45 ℃,乙烯压力为4 MPa,n(Al)/n(Cr)=300,催化剂用量为7 μmol时,活性可达1.32×10⁵ g/(mol(Cr)·h),C₆和C₈的选择性为59.30%。     

高效率钙钛矿型太阳能电池的化学稳定性及其研究进展

近几年来, 钙钛矿太阳能电池器件光电转换效率的最高纪录不断被刷新, 但是关于钙钛矿太阳能电池稳定性的研究报道比较缺乏. 钙钛矿太阳能电池稳定性问题已经成为制约钙钛矿太阳能电池继续发展的瓶颈. 简要讨论了水氧气氛、温度变化、湿法制备、紫外光照等不同敏感环境条件下钙钛矿太阳能电池的化学稳定性问题, 进而对一定环境条件下钙钛矿太阳能电池的化学稳定性及其调控的研究现状进行了综述, 旨在更好地理解钙钛矿太阳能电池稳定性的基础理论问题, 为实现钙钛矿太阳能电池稳定性的调控提供基本依据.     

掺Cr3+玻璃陶瓷光谱特性

采用分析纯原料,利用分相成核制备了利用性良好的掺Ｃｒ＾３＋Ｂ２Ｏ３－Ａｌ２Ｏ３－ＳｉＯ２系透明玻璃陶瓷;测定了材料的吸收光谱和发射光谱,分析了讨论了光谱特性。     

负载型钯催化剂硫中毒机理—模型催化剂的评价及表征

以H_2S为毒物,H_2-O_2反应为模型反应,用浸渍法制备了一系列Pd/Al_2O_3催化剂,用交替-脉冲微反应色谱技术对催化剂活性、耐硫性进行评价,用XPS、红外分析技术对不同反应阶段的催化剂进行了表征。结果表明:在一定条件下,虽然催化剂上有S_2~(2-)、S~(2-)和SO_4~(2-)物种存在,其活性也基本相同,但耐硫性差别较大。当催化剂上有S_2~(2-)存在时,其耐硫性较差,含有S~(2-)的催化剂次之,含有SO_4~(2-)的催化剂的耐毒性较好。SO_4~(2-)对催化剂的主要影响是降低了催化剂的活性,而对抗硫性影响不大。由此可以认为,H_2-O_2反应中负载型钯催化剂硫中毒时,以S_2~(2-)毒性最大,其次是S~(2-),在一定范围内SO_4~(2-)的毒性较小。     

Flexible Substrates with Polyimide Buffer Layers for Organic Light-Emitting Diodes

We report a new method to enhance the properties of the polyethyleneterephthalate (PET) substrates for flexible organic light-emitting diodes (OLEDs). By spin-coating a polyimide (PI) film between the PET and the indiumtin-oxide anode, the flexible substrate with a smooth surface, high transmission over the visible spectrum and     

An estimation formula for the average path length of scale-free networks

A universal estimation formula for the average path length of scale free networks is given in this paper. Different from other estimation formulas, most of which use the size of network, $N$, as the only parameter, two parameters including $N$ and a second parameter $\alpha $ are included in our formula. The parameter $\alpha $ is the power-law exponent, which represents the local connectivity property of a network. Because of this, the formula captures an important property that the local connectivity property at a microscopic level can determine the global connectivity of the whole network. The use of this new parameter distinguishes this approach from the other estimation formulas, and makes it a universal estimation formula, which can be applied to all types of scale-free networks. The conclusion is made that the small world feature is a derivative feature of a scale free network. If a network follows the power-law degree distribution, it must be a small world network. The power-law degree distribution property, while making the network economical, preserves the efficiency through this small world property when the network is scaled up. In other words, a real scale-free network is scaled at a relatively small cost and a relatively high efficiency, and that is the desirable result of self-organization optimization.     

新型热释电多功能能量卡计测量系统

简要介绍了新型热释电多功能能量卡计测量系统的结构、工作原理和系统的特点。给出了用该系统监测强激光打靶时的能量平衡率、能量吸收系数及受激拉曼散射(SRS)角分布测量的部分实验结果。尤其是测得的1060nm强激光打靶后产生的SRS光在0°～15°区域内的实验点和角分布情况在国内外尚属首批数据。     

$FI$-$t$-提升模和$t$-quasi-dual Baer模

本文引入$FI$-$t$-提升模和$t$-quasi-dual Baer模的概念并给出两者的联系.证明富足补模$M$为$FI$-$t$-提升模当且仅当$M$的每个完全不变$t$-coclosed子模为$M$的直和项当且仅当$\bar{Z}^{2}(M)$为$M$的直和项且$\bar{Z}^{2}(M)$为$FI$-$t$-提升模当且仅当$M$同时为$t$-quasi-dual Baer 模和$FI$-$t$-$\mathcal{K}$-模.