夹心三明治结构的二十五核银硫簇合物[Ag_(25)(SC_6H_4Pr~i)_(18)(dppp)_6](CF_3SO_3)_7·CH_3CN:结构表征及光学性能（英文）

在本研究中,使用(~iPrC_6H_4SAg)_n作为合成银硫纳米簇合物的前驱体。当存在辅助的双膦配体1,3·双(二苯基膦)丙烷(dppp)及可溶性银盐(CF_3S0_3Ag),在超声合成条件下,获得了一例二十五核银硫簇合物Ag_(25),并借助X射线单晶衍射技术确定相应的分子结构。该银硫簇合物具有夹心三明治的骨架结构:分别由两个结构相似的圆柱体共享一个七核纯银簇所构成的金属簇平面。固态紫外可见漫反射光谱测试表明该簇合物的能级带隙为2.5 eV,属于半导体材料的范畴。固态发光测试显示,该簇合物在室温下发射绿光。     

Hydrogenation of Furfural to Furfuryl Alcohol over Co-B Amorphous Catalysts Prepared by Chemical Reduction in Variable Media

Five Co-B amorphous alloy catalysts were prepared by chemical reduction in different media, including pure water and pure ethanol as well as the mixture of ethanol and water with variable ethanol content, Their catalytic properties were evaluated using liquid phase furfural hydrogenation to furfuryl alcohol as the probe reaction. It was found that the reaction media had no significant influence on either the amorphous structure of the Co-B catalyst or the electronic interaction between metallic Co and alloying B. This could successfully account for the fact that all the as-prepared Co-B catalysts exhibited almost the same selectivity to furfuryl alcohol and the same activity per surface area （ Rs ）, which could be considered as the intrinsic activity, since the nature of active sites remained unchanged. However, the activity per gram of Co （ R^mH ） of the as-prepared Co-B catalysts increased rapidly when the ethanol content in the water-ethanol mixture used as the reaction medium for catalyst preparation increased. This could be attributed to the rapid increase in the surface area possibly owing to the presence of more oxidized boron species which could serve as a support for dispersing the Co-B amorphous alloy particles.     

A Novel Inorganic-Organic Composite Constructed from Cobalt（Ⅱ）-Monosubstituted Polyoxometalates and Poly（amidoamine）-NH2 DendrimersA Novel Inorganic-Organic Composite Constructed from Cobalt（Ⅱ）-Monosubstituted Polyoxometalates and Poly（amidoamine）-NH2 Dendrimers

An inorganic-organic composite was prepared by poly（amidoamine） （PAMAM） dendrimer reacting with cobalt（Ⅱ）-monosubstituted polyoxometalates Na5Co^Ⅱ（H2O）PW11O39 （PW11CO） in an aqueous solution. The hybrid composite PW11Co/PAMAM was characterized by FT-IR, UV-Vis diffuse reflectance spectra （DR-UV-Vis）, XPS, XRD and TG/DTA, indicating that the PWI iCo was chemically anchored to PAMAM. The morphologies of the title composite were characterized by scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The catalytic activity was evaluated by oxidation of isobutyraldehyde （IBA） to isobutyric acid （IBAc） in MeCN under mild conditions （20 ℃, ambient pressure）, showing that the title compound is a more effective and recoverable catalyst than corresponding PW11Co.     

碳酸的动力学稳定性

介绍了单体碳酸的动力学稳定性 ,讨论了水分子对碳酸分解速率的影响及溶液中碳酸不稳定的原因     

加氢精制催化剂的状态对吡啶加氢脱氮活性的影响

发现在同样反应条件下,各种不同类型的加氢精制催化剂还原态比硫化态的吡啶加氢脱氮活性要高得多,某些催化剂的吡啶脱氮率甚至要高出一个数量级以上。通过研究Ni/Ni+W原子比与硫化态和还原态NiO-WO_3/Al_2O_3催化剂吡啶加氢脱氮活性的关系,可以清楚地看出:在硫化态催化剂中钨的硫化物是主要活性组份,而镍的硫化物是助剂;另一方面,在还原态催化剂中主要活性物质是镍。通过对吡啶加氢脱氮反应机理的分析,认识到金属Ni和金属Co不仅具有很高的加氢功能,对氮己环中的C-N键断裂也具有很高的氢解功能。用热重法对NiO-WO_3/Al_2O_3催化剂体系进行还原动力学研究的结果表明:催化剂的还原度和初始还原活化能与吡啶加氢脱氮活性之间有很好的对应关系。对催化剂还原过程的动力学数据分别用Elovich方程和核增长模型进行数据处理,结果表明,Elovich方程能更好地反映催化剂还原的动力学特征。     

稀土催聚顺-1,4-聚异戊二烯的表征

稀土催化聚合的顺-1,4-聚异戊二烯(Ln—PIR)的顺式含量比天然橡胶(NR)略低,其长链分子无支化.Ln—PIR生胶本体结晶的Avrami指数n值高达7以至8.与Ti-PIR及NR相同,松弛模量依赖于缠结链段的分子量.屈服过程的开始与链的解缠结的开始相当,两个过程的活化能各约为8KJ/mol.,不论是屈服或缠结的出现,用屈服强度法与应力松弛法这两种独立方法所测得的临界分子量Mc值等于(5.4±0.2)×104,此值又与用折合屈服强度法所求得的Mc值相当.     

高效液相色谱法测定羊体内的丙硫咪唑缓释弹代谢产物的血药浓度

用反相高效液相色谱法追踪分析不同时间内羊血清中药物浓度的变化，以供药物代谢动力学研究。药物为丙硫咪唑砜和丙硫咪唑亚砜（简称砜和亚砜），实验条件为ＯＤＳ柱，流动相甲醇：水＝７：３（ｖ／ｖ），紫外检测波长为２９０ｎｍ。在３ｈ左右测定浓度达峰值，其最高浓度分别为４．０１μｇ／ｍＬ和１１．４７μｇ／ｍＬ，五天左右下降为２．７３μｇ／ｍＬ和１．３２μｇ／ｍＬ附近。最小检出量为０．４ｎｇ／ｍＬ及０．７ｎｇ／ｍＬ。线性关系良好。丙硫咪唑砜和亚砜的回归相关系数分别为０．９９９４和０．９９９１。采用内标法测定回收率，平均为１００±１２％。     

Group velocity matters for accurate prediction of phonon-limited carrier mobility

First-principles approaches have recently been developed to replace the phenomenological modeling approaches with adjustable parameters for calculating carrier mobilities in semiconductors. However, in addition to the high computational cost, it is still a challenge to obtain accurate mobility for carriers with a complex band structure, e.g., hole mobility in common semiconductors. Here, we present a computationally efficient approach using isotropic and parabolic bands to approximate the anisotropy valence bands for evaluating group velocities in the first-principles calculations. This treatment greatly reduces the computational cost in two ways: relieves the requirement of an extremely dense κ mesh to obtain a smooth change in group velocity, and reduces the 5-dimensional integral to 3-dimensional integral. Taking Si and SiC as two examples, we find that this simplified approach reproduces the full first-principles calculation for mobility. If we use experimental effective masses to evaluate the group velocity, we can obtain hole mobility in excellent agreement with experimental data over a wide temperature range. These findings shed light on how to improve the first-principles calculations towards predictive carrier mobility in high accuracy.     

负载型Pd-Cu催化剂的制备及富氢气氛下CO优先氧化性能

分别以Al₂O₃, SiO₂和C₃N₄为载体, 通过简单浸渍法制备了3种负载型Pd-Cu催化剂(PC-Al₂O₃, PC-SiO₂, PC-C₃N₄), 考察了其在室温下富氢气氛中CO优先氧化反应性能. 采用X射线衍射(XRD)、 傅里叶变换红外光谱(FTIR)、 氮气物理吸附仪(N₂-physisorption)、 氢气程序升温还原(H₂-TPR)、 二氧化碳程序升温脱附(CO₂-TPD)、 X射线光电子能谱(XPS)和原位漫反射傅里叶变换红外光谱(In situ DRIFTS)等手段对其进行了表征. 结果表明, 与PC-SiO₂和PC-C₃N₄相比, PC-Al₂O₃具有更高的CO优先氧化性能. 这是由于PC-Al₂O₃上形成了大量与Pd物种具有强相互作用的Cu₂Cl(OH)₃物种; 而PC-SiO₂中仅有少量的Cu₂Cl(OH)₃, 且与Pd物种相互作用较弱; PC-C₃N₄中Cu物种则更易与C₃N₄基质配位, 由此削弱了Pd, Cu之间的相互作用. 在反应气氛下PC-Al₂O₃表面还易形成具有更强CO活化能力的Pd⁺物种, 通过与大量Cu⁺物种紧密相互作用, 在一定程度上抑制Pd⁺被过度还原为Pd⁰, 从而维持了其催化活性. 与SiO₂和C₃N₄相比, Al₂O₃更适合负载Pd-Cu用于富氢气氛下CO优先氧化反应.     

基于纳米多孔硅烷薄膜的适体电化学传感器用于黄曲霉毒素B1的检测

构建了一个基于纳米多孔硅烷薄膜的适体电化学传感器,用于中草药中的黄曲霉毒素B1(AFB1)的灵敏检测。以溶胶-凝胶溶液电沉积再洗脱的方法在活化的玻碳电极表面制备了孔隙均匀,结构稳定的纳米多孔硅烷薄膜,并在此基础上沉积了金纳米粒子,为巯基修饰的适配体提供了大量的活性位点。利用AFB1与适配体的特异性结合能力,将适配体上吸附的信号分子亚甲基蓝（MB）与目标物AFB1形成竞争关系,以此来定量检测AFB1,线性范围在0.01～75μg/L,检出限为5.6 ng/L。方法应用于3种中草药（当归、黄芪、党参）的加标回收检测,结果满意。本传感器的构建为检测AFB1提供了一个新的思路。