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41.
Waugh-型镍钼杂多酸的量子化学计算   总被引:1,自引:0,他引:1  
采用半经验INDO法,完成了Waugh-型镍钼杂多酸(NH44)6〔NIMO9O32〕·6H2O的量子化学计算,得到146个成键轨道和78个反键轨道,轨道能级,电荷和键序等数据。通过对这些数据的分析,表明杂多酸分子中端氧和Ni都可能为化学活性中心,各原子轨道在分子轨道中都占有一定比例,其HOMO和LUMO能级皆为负值,其体系具有进一步接受电子的能力。这些结论与实验事实一致。  相似文献   
42.
有机分子与聚电解质静电吸附成膜特性研究   总被引:1,自引:0,他引:1  
选取多种有机分子及聚电解质,采用静电吸附自组装法制备了聚电解质,聚电解质、聚电解质,有机分子、有机分子,有机分子的复合薄膜,讨论了这些体系的静电吸附成膜特性及其成膜机理.  相似文献   
43.
本文首先运用考虑非期望产出的SBM-SupSBM模型估计我国各省市绿色技术创新效率并进行分类:稳定上升类、平稳类、大幅度波动类以及下降类。之后从企业内部和外部两方面对绿色技术创新效率提升的影响因素提出假设,着重考虑大幅度波动类别省份的效率提升。运用面板数据模型各影响因素进行验证,结论显示:企业规模对绿色技术创新效率波动较大的省份起到显著的抑制作用,环境规制和技术进步对绿色技术创新效率波动较大的省份作用不明显。针对分析结果,提出结论:在提升绿色技术创新效率的过程中,应注重企业规模和技术进步的协同作用,以及技术的开放程度。  相似文献   
44.

As an important research direction, operational research (OR) has always attracted scholars worldwide. We study the structure, trend and prospect in the OR field by conducting a bibliometric analysis of publications in the period of 1952–2020, which are included in the Web of Science (WoS) database. Using three effective bibliometric tools, namely, VOS viewer, CiteSpace, and Bibliometrix, a total of 5,353 publications were retrieved to show clear visual results using a series of scientific analyses. First, a performance analysis revealed the basic characteristics of publications considering the type distribution, annual trend, quantity and quality. Then, a cooperation analysis presented the influential countries/regions and showed the relationships among countries/regions, institutions and authors during different periods based on bibliometric indicators and co-authorship networks. Moreover, a keyword analysis was conducted to investigate the hot topics and development of the OR field, using co-occurrence analysis, timeline view analysis and evolution analysis. Finally, we discussed the implications and limitations, and summarized the main findings. This study hopes to provide important and valuable references for future research on the OR field.

  相似文献   
45.
Compound 1 (1-(3-chlorophenyl)-4-[1-(4-cyanobenzyl)imidazolylmethyl]-2-piperazinone hydrochloride) is a farnesyl transferase inhibitor intended for treatment of cancer. A detailed analysis of the electrospray ionization mass spectrometry and tandem mass spectrometry data of protonated 1 shows that in the gas phase, upon collision-induced dissociation, this ion undergoes complicated rearrangement and fragmentation. These processes include a novel two-step rearrangement. The first step involves a gas-phase intramolecular S(N)2 reaction that forms an intermediate. The second step consists of three competitive rearrangement/fragmentation pathways of the intermediate, giving rise to protonated 2, protonated methylene-imidazole, and a distonic methylimidazole radical cation. Deuterated 1 was studied under the same experimental conditions, and the results strongly support the proposed two-step rearrangement process. It is noted that the unique structure of 1, especially the imidazole ring of 1, plays a critical role in the rearrangement of protonated 1.  相似文献   
46.
The phenomenon of migration of the silyl groups from α-oxygen to β-oxygen in sodium aldol reaction was observed for the first time in this paper.  相似文献   
47.
血浆样品经0.01mol·L-1盐酸和无水乙醇浸取,在碱性条件下用氯仿萃取,GG-MS-选择离子测量法测定,外标法定量。在选定的色谱条件下,盐酸克仑特罗的检出限为0.05ng,线性范围为0.1-100ng,方法的平均回收率为95.6%,RSD小于6.82%(n=6)。该法毋需衍生化,基质无干扰,简便可靠,适用于生物材料中克仑特罗的快速分析。  相似文献   
48.
The inhibitors of 4-hydroxyphenylpyruvate dioxygenase (HPPD, EC 1.13.11.27) are an new kind of herbicides.[1]Generally, in structure, potent herbicides of this kind must possess: (1) a tricarbonyl methane structure and one of the three carbonyl groups must be a subustituted benzoyl group; (2) the compound must be able to enolise so that the enolate is capable of inhibiting HPPD enzyme by competitive combination with Fe2+, the reaction center of HPPD enzyme.[2]Recently, we noticed that the 3-acyltetramic acids form an expanding group of antibiotics and pigments from micro-organisms,[3] they display a range of biological activities[4] and all of this kind compounds possess all of the characters mentioned above. Tests of their antimicrobial activities indicated that the structure of the acyl substituent at the 3-position was important to many typical antibiotics.[4~6] These characters stimulated us to study this kind of compounds so as to discover new herbicides. In this report, we synthesized a series of compounds 3 and tested their herbicidal activities to investigate their structure-activity relationships.  相似文献   
49.
The interaction of tetrandrine with human serum albumin (HSA) was studied by measuring fluorescence quenching spectra, synchronous fluorescence spectra and ultra-violet spectra. The fluorescence quenching spectra of HSA in the presence of tetrandrine showed that tetrandrine quenched the fluorescence of HSA. The quenching constants of tetrandrine on HSA were determined using the Stern-Volmer equation. Static quenching and non-radiation energy transfer were the two main reasons leading to the fluorescence quenching of HSA by tetrandrine. According to the F?rster theory of non-radiation energy transfer, the binding distances (r) and the binding constants (K(A)) were obtained. The thermodynamic parameters obtained in this study revealed that the interaction between tetrandrine and HSA was mainly driven by a hydrophobic force. The conformational changes of HSA were investigated by synchronous spectrum studies.  相似文献   
50.
A new series of MR-IPN polyacrylamide—poly(vinyl-ethylenediamine)chelatesorbents were prepared by the reaction of ethylenediamine with MR-IPN matrixes.The newchelate sorbent showed good sorption properties for auric and platinic ions.  相似文献   
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