高温超导体制备条件的人工神经网络识别

高温超导体的制备条件要求严格,其掺杂量大小、烧结温度控制等都直接影响实验样本的超导性质。近几年高温超导研究已积累大量实验数据,如何应用人工智能方法处理这些数据寻找更好的合成条件颇有意义。人工神经网络方法在许多领域己显示其处理复杂数据和模式识别的优越性,但尚未应用到化合物制备研究方面。本文对此作了初步尝试。     

Theoretical investigation of the decarbonylation of acetaldehyde by Fe+ and Cr+.

We report a comprehensive theoretical study on the decarbonylation of acetaldehyde by Fe+ and Cr+. Various intermediates, transition states, and products involved in the decarbonylation reactions are fully optimized at the B3LYP/6-311+G(2df,2pd) level of theory. The potential energy surfaces (PESs) corresponding to [M,O,C2,H4]+(M=Cr and Fe) are examined in detail using B3LYP and CCSD(T) methods, respectively. The validity of these theoretical methods is calibrated with respect to the available thermochemical data. Calculations suggest that the Cr+ mediated decarbonylation of acetaldehyde takes place in four steps on the sextet surface: encounter complexation, C-C activation, aldehyde H-shift, and nonreactive dissociation, in good accordance with the Co+ mediated decarbonylation of acetaldehyde [Zhao, Zhang, Guo, Wu, Lu, Chem. Phys. Lett. 2005, 414, 28], while for the Fe+/acetaldehyde system decarbonylation can occur on both the quartet and the sextet PESs. The quartet pathway, which experiences spin-orbit coupling between the two surfaces, is energetically more favorable; whereas along the sextet decarbonylation coordinate several high-energy barriers are revealed. The theoretical results are compared with the experimental product kinetic energy and angular distributions of decarbonylation of acetaldehyde by Fe+ and Cr+ measured using a crossed-beam technique [Sonnenfroh, Farrar, J. Am. Chem. Soc. 1986, 108, 3521].     

重油催化裂化汽油中含氮化合物的分析

利用酸萃取技术浓缩分离重油催化裂化（RFCC）汽油中的氮化物，比较了两种萃取剂和两种油剂比对分离效果的影响，结果发现选用10％（体积分数）HCl作萃取剂，油剂比为10：1（体积比）时，碱性氮化物的提取率较高；浓缩分离出的氮化物用色谱－质谱联用方法对其进行了检测，结果表明RFCC汽油中的氮化物主要是C0－C2苯胺及少量吡啶类、喹啉类碱性氮化物。     

Comparing ordered-entry queues with heterogeneous servers

We study a queueing system withm exponential servers with distinct service rates. Jobs arrive at the system following an arbitrary point process. Arrived jobs receive service at the first unoccupied server (if any) according to an entry order , which is a permutation of the integers 1, 2,...,m. The system has a finite buffer capacity. When the buffer limit is reached, arrivals will be blocked. Blocked jobs will either be lost or come back as New arrivals after a random travel time. We are concerned with the dynamic stochastic behavior of the system under different entry orders. A partial ordering is established among entry orders, and is shown to result in some quite strong orderings among the associated stochastic processes that reflect the congestion and the service characteristics of the system. The results developed here complement existing comparison results for queues with homogeneous servers, and can be applied to aid the design of conveyor and communication systems.     

氨基酚异构体的离子对反相液相色谱分析的研究

本文研究了离子对反相液相色谱分析氨基酚异构体的可能性、影响因素和色谱条件，发现以含４×１０－８ｍｏｌ／Ｌ四丁基碘化铵、０．１８４ｍｏｌ／Ｌ醋酸钠的甲醇水溶液（２３：７７）作为流动相，ＯＤＳ为固定相时可以实现氨基酚异构体的良好分离。     

烯丙基碘和锡与醛的选择加成反应

含活性基团的醛可与烯丙碘和锡粉直接进行亲核加成反应，得到高烯丙基的醇，水的存在不利于此反应的进行，与烯丙基溴相比，烯丙基碘反应活性更强，可在短时间内得较高的产率。     

氯取代硫三碳菁染料的合成及性能

本文合成了七个硫三碳菁.其中四个具有桥环的菁染料。测定了它们的电子吸收光谱,讨论了结构对光稳定性的影响。并发现镍络合物能有效地抑制菁染料的光退色。     

三碳菁染料的研究

三碳菁染料的吸收在近红外区,可用作卤化银感光材料的红外增感染料,近年来在红外激光染料和光信息记录介质等方面也得到了开发及应用。在多甲川链上引入桥环可提高染料的稳定性。本文合成了9种含芳胺基取代的桥链三碳菁,讨论染料结构与其增感性能关系。     

Molecular structure and nanosecond optical limiting property of a typical silver cubane-like cluster containing tetraselenotungstate

A typical silver cubane-like heteroselenometallic cluster, (μ₃-WSe₄)Ag₃(PPh₃)₃Cl·0.5SePPh₃, was synthesized from reaction of [Et₄N]₂[WSe₄] and Ag(PPh₃)₂(NO₃) in CH₂Cl₂ solution and structurally characterized by X-ray crystallography. The compound crystallizes in the trigonal space group R3 with a=16.258(4), b=22.80(3) Å, V=5217(7) ų, and Z=3. The structure contains a strongly distorted cubane-like {WAg₃Se₃Cl} core. The coordination geometries of the W center and each Ag atom are tetrahedral. The mean W-Ag separation is 3.010(3) Å. Optical nonlinearity of this cubane-like cluster was studied. Large optical limiting effect with threshold of 0.45 J/cm² was observed with the laser pulses of 7 ns at 532 nm.     

聚乙烯醇双胺肟螯合纤维的合成及其吸附性能

利用预辐接技法合成了聚乙烯醇双胺肟螯合纤维。研究了影响接枝率和胺肟基团含量的因素，讨论了吸附酸度、吸附时间对Ｃｕ（Ⅱ）离子吸附容量的影响。