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On the Structure of the Arginine-carboxylate Salt Bridge:A Density Functional Theory Study

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Chinese Chemical Letters 2001年第3期12卷 219-222页

作者： Ting Wei MU Yong FENG Lei LIU qing xiang GUO Department of Chemistry University of Science and Technology of ChinaHefei 230026

High level density functional theory (DFT) calculations are performed for the first time to answer the question whether the arginine-carboxylate salt bridge stays in a zwitterionic state or a neutral one. The results indicate that in the gas phase, the neutral form is more stable and hence proton transfer occurs from guanidinium to carboxylate. However, in an aqueous solution the zwitterionic form should be favored. The difference might he caused by the electrostatic interaction between the salt bridge and its molecular environment. Therefore, the solvation effect has to be considered in the modeling of proteins, whose stabilization depends heavily on the salt-bridges.

关键词： Arginine-carboxylate interaction salt bridge DFT proton transfer solvation effect

Study on Dragline-Bulldozer Operation with Variations in Coal Seam Thickness

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Journal of China University of Mining and Technology 2007年第4期17卷 464-466页

作者： ZHOU Wei CAI qing-xiang CHEN Shu-zhao School of Mining and Safety Engineering China University of Mining ＆Technology Xuzhou Jiangsu 221008 China

The dragline is one of the most promising surface mining machines in China. This paper studies the interac-tion between the working bench advancing speed and the stripping volume with variation in coal seam thickness. Ad-justing the bulldozing volume (depth) and/or changing the dragline bench height are proposed as means to ensure a smooth and economical mining operation. When the coal seam is getting thicker it is recommended to reduce the bull-dozing volume (depth) for a higher dragline efficiency. When the coal seam is getting thinner it is recommended to in-crease the bulldozing volume (depth) to ensure the dragline can work at the proper bench height.

关键词： open pit coal thickness variation dragline adaptability bulldozer

Diagonal Invariant Ideals of Topologically Graded C~*-algebras

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Chinese Quarterly Journal of Mathematics 2005年第4期20卷 338-341页

作者： XU qing-xiang ZHANG Xiao-bo Department of Mathematics Shanghai Normal University Shanghai 200234 China

We study diagonal invariant ideals of topologically graded C*-algebras over discrete groups. Since all Toeplitz algebras defined on discrete groups are topologically graded, the results in this paper have improved the... 详细信息

关键词： Fell bundle topologically graded C*-algebra diagonal invariant ideal

Synthesis of α-Arylated Esters from Aryl Halides

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Chinese Chemical Letters 2006年第5期17卷 595-598页

作者： Wei DENG Ye Feng WANG Lei LIU qing xiang GUO Department of Chemistry University of Science and Technology of China Hefei 230026

An operationally simple and inexpensive catalyst system was developed for the cross coupling of aryl iodides and bromides with ethyl acetoacetate by using CuI as catalyst and Nmethyl glycine as ligand. The reaction represents a novel Cu-catalyzed C-C cross coupling reaction. This procedure is applicable to the preparation of pharmaceutically important α- arylalkanoic acids.

关键词： Cross coupling reaction CuI ethyl acetoacetate aryl halide α-arylalkanoic acids.

A Statistical Examination on the Compensation between the Enthalpies and Entropies Obtained from the Calorimetric Methods

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Chinese Chemical Letters 2001年第2期12卷 167-170页

作者： Lei LIU Chao YANG Ting Wei MU qing xiang GUO Department of Chemistry University of Science and Technology of ChinaHefei 230026 Department of Chemistry Columbia UniversityNew YorkNY 10027

The validity of the compensation between the enthalpies and entropies obtained from the calorimetric methods was statistically examined for the first time based on computer simulations. It turned out that several claimed enthalpy-entropy compensations in literature based upon the calorimetric measurements were statistically correct. Interestingly, a linear relationship between the slopes and correlation coefficients of the T DeltaS-DeltaH plots of different physical origin of the compensation behavior.

关键词： Calorimetry enthalpy-entropy compensation molecular recognition solvent reorganization statistics

Cu(I)/Diamine-catalyzed Aryl-alkyne Coupling Reactions

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Chinese Chemical Letters 2005年第9期16卷 1197-1200页

作者： Ye Feng WANG Wei DENG Lei LIU qing xiang GUO Department of Chemistry University of Science and Technology of China Hefei 230026

CuI/ethylene diamine/K2CO3/dioxane is shown to be a useful system for the cross coupling reactions of various aryl iodides and bromides with aryl and alkyl alkynes. Compared to the conventional Sonogashira reactions, ... 详细信息

关键词： Sonogashira coupling reaction CuI aryl halide alkyne diamine

基于SEM的建筑安装工程施工安全风险评价方法

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建筑技术开发 2024年第4期51卷 115-117页

作者：孟庆祥李龙李永强中建二局第一建筑工程有限公司北京100176

由于各种安全风险因素之间存在相互作用,建筑安装工程施工安全风险评价的可靠性难以保证,为此,提出基于SEM的建筑安装工程施工安全风险评价方法。首先对建筑安装工程施工安全风险的特点进行分析,并明确评价的目标和要求。然后,采用结构... 详细信息

由于各种安全风险因素之间存在相互作用,建筑安装工程施工安全风险评价的可靠性难以保证,为此,提出基于SEM的建筑安装工程施工安全风险评价方法。首先对建筑安装工程施工安全风险的特点进行分析,并明确评价的目标和要求。然后,采用结构方程模型作为评价工具,构建建筑安装工程施工安全风险评价模型,模型包括多个评价指标和路径关系,全面考虑各种安全风险因素之间的相互作用。通过模型分析和计算,准确评估施工安全风险水平。测试结果表明,设计评价方法实现了对建筑安装工程施工安全风险的准确评价。

关键词： SEM 安全风险特点安全风险评价模型

Gd对Fe_(66)Cr_(2)Nb_(4)Y_(6)B_(22)合金的非晶形成能力和力学性能的影响

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铸造 2024年第9期73卷 1218-1224页

作者：张娜张伟武彧婷向青春任英磊邱克强沈阳工业大学材料科学与工程学院辽宁沈阳110870

Gd作为优异的中子吸收剂,在中子吸收元素中具有最大的热中子俘获截面。采用铜金属型铸造法研究了Fe_(66)Cr_(2)Nb_(4)Y_(6-x)Gd_(x)B_(22)(x=2,4,5,6 at.%)合金的非晶形成能力及力学性能。结果表明:当Gd含量为2 at.%和4 at.%时,两种合... 详细信息

Gd作为优异的中子吸收剂,在中子吸收元素中具有最大的热中子俘获截面。采用铜金属型铸造法研究了Fe_(66)Cr_(2)Nb_(4)Y_(6-x)Gd_(x)B_(22)(x=2,4,5,6 at.%)合金的非晶形成能力及力学性能。结果表明:当Gd含量为2 at.%和4 at.%时,两种合金的非晶形成能力分别为3 mm和4 mm。进一步提高Gd含量,合金的非晶形成能力低于3 mm。Fe_(66)Cr_(2)Nb_(4)Y_(2)Gd_(4)B_(22)合金具有最大的非晶形成能力,其过冷液相区ΔT_(x)、约化玻璃转变温度T_(rg)和非晶形成能力判定参数γ均达到最大值,分别为56 K,0.6673和0.4241。但是Fe_(66)Cr_(2)Nb_(4)Y_(6-x)Gd_(x)B_(22)(x=2 at.%,4 at.%,5 at.%)非晶合金的抗压强度和显微硬度随Gd含量的增加而降低。

关键词： Fe基非晶合金 Gd添加非晶形成能力力学性能

海马-杏仁核脑深部电刺激术治疗难治性内侧颞叶癫痫长期疗效及其对认知功能的影响

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中国现代神经疾病杂志 2024年第7期24卷 540-546页

作者：苏乐王健赵虎林凌至培王湘庆崔志强华北理工大学临床医学院研究生院唐山063000 解放军总医院第一医学中心神经外科医学部北京100853 解放军总医院海南医院神经外科三亚572013 解放军总医院第一医学中心神经内科医学部北京100853

目的探讨海马-杏仁核脑深部电刺激术(AH-DBS)治疗难治性内侧颞叶癫痫的长期疗效及其对认知功能的影响。方法共纳入2014年1月至2018年12月解放军总医院第一医学中心收治的7例难治性内侧颞叶癫痫患者,均行AH-DBS,对比手术前后癫痫发作... 详细信息

目的探讨海马-杏仁核脑深部电刺激术(AH-DBS)治疗难治性内侧颞叶癫痫的长期疗效及其对认知功能的影响。方法共纳入2014年1月至2018年12月解放军总医院第一医学中心收治的7例难治性内侧颞叶癫痫患者,均行AH-DBS,对比手术前后癫痫发作形式、发作频率和抗癫痫发作药物应用情况,采用韦氏成人智力量表修订版(WAIS-R)评估认知功能;术后记录刺激参数以及手术相关并发症。结果共7例患者行双侧AH-DBS 4例,左侧AH-DBS 2例,左侧AH-DBS联合右侧颞前叶切除术1例;经枕部入路6例,经额部入路1例;仅1例患者术后出现头皮切口愈合不良,经局部植皮后痊愈。术后平均随访(73.00±8.98)个月,随访期间复杂部分性发作频率[1.00(0.00,31.00)次/月对2.00(1.50,60.00)次/月;Z=-2.207,P=0.027]、继发性全面性强直-阵挛发作频率[0.00(0.00,1.00)次/月对2.00(1.00,3.00)次/月;Z=-2.428,P=0.015]和总发作频率[1.00(0.50,31.00)次/月对5.00(2.50,64.00)次/月;Z=-2.366,P=0.018]均较术前减少,而手术前后抗癫痫发作药物种类[1.00(1.00,2.00)种对1.00(1.00,3.00)种;Z=-1.633,P=0.102]和WAIS-R评分[(85.50±7.09)分对(89.00±9.47)分;t=-1.761,P=0.078]差异无统计学意义。结论 AH-DBS作为一种新型抗癫痫治疗方法,可以减少难治性内侧颞叶癫痫发作频率,无严重不良事件,且对认知功能无明显影响。

关键词：癫痫颞叶深部脑刺激法海马杏仁核认知