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分子动力学模拟研究两性离子结构对聚13丙氨酸(polyalanine13)在水溶液中天然行为的维持 分子动力学模拟研究两性离子结构对聚13丙氨酸(polyalanine13)在水溶液中天然行为的维持
Science in China. Series B, Chemistry Pub Date : 2008-01-20 DOI: 10.1360/zb2008-38-1-48
朱皓淼, 李波, 李利, 沈健
{"title":"分子动力学模拟研究两性离子结构对聚13丙氨酸(polyalanine13)在水溶液中天然行为的维持","authors":"朱皓淼, 李波, 李利, 沈健","doi":"10.1360/zb2008-38-1-48","DOIUrl":"https://doi.org/10.1360/zb2008-38-1-48","url":null,"abstract":"用分子动力学方法模拟了水溶液中聚13丙氨酸分子(A13)由α-螺旋二级结构(α-helix )向无规线团(radom coil)转变的初期过程, 以及同样条件下A13分子分别与两性离子材料表面和疏水性材料表面作用的行为. 二级结构分析、氢键分析、均方根偏移、二面角分布和吸附程度分析结果显示, 两性离子材料表面对在水环境中A13分子的正常行为影响较小. 间接证明了“维持正常构象”假说.","PeriodicalId":49128,"journal":{"name":"Science in China. Series B, Chemistry","volume":"12 5 1","pages":"48-54"},"PeriodicalIF":0.0,"publicationDate":"2008-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81623800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
非聚集态、聚集态 β -淀粉样蛋白(10-21)和外向钾通道的相互作用 非聚集态、聚集态 β -淀粉样蛋白(10-21)和外向钾通道的相互作用
Science in China. Series B, Chemistry Pub Date : 2007-10-20 DOI: 10.1360/ZB2007-37-5-489
张朝峰, 樊丽 Sub, 杨频 Sub
{"title":"非聚集态、聚集态 β -淀粉样蛋白(10-21)和外向钾通道的相互作用","authors":"张朝峰, 樊丽 Sub, 杨频 Sub","doi":"10.1360/ZB2007-37-5-489","DOIUrl":"https://doi.org/10.1360/ZB2007-37-5-489","url":null,"abstract":"金属离子诱导的A β 聚集是阿尔兹海默病发病机理中的一个关键因素, Zn 2+ 是唯一能够在生理pH条件下诱导A β 聚集的过渡金属离子, 弄清Zn 2+ 诱导的A β 聚集对神经细胞的毒害作用是深入了解A β 作用机理的关键. 选取A β (10-21)为模型片断, 以海马CA1区锥形细胞为研究对象, 首次采用光谱法和膜片钳技术相结合的方法, 从细胞层次对Zn 2+ , A β , 离子通道三者的相互关系进行了初步研究, 阐述了两种状态 (非聚集态、聚集态) 的Ab (10-21)对海马细胞外向钾通道三种过程(激活过程、失活过程、复活过程)的影响以及作用方式, 从通道水平说明了A β 对神经细胞毒害作用的分子机理. 以上结果对深入了解A β 致病机理及新型靶向性药物的开发具有重要意义.","PeriodicalId":49128,"journal":{"name":"Science in China. Series B, Chemistry","volume":"10 1","pages":"489-496"},"PeriodicalIF":0.0,"publicationDate":"2007-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85172704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
铜(II)-氟喹诺酮类抗生素螯合物与赤藓红体系的吸收、荧光和共振Rayleigh散射光谱及其分析应用研究 铜(II)-氟喹诺酮类抗生素螯合物与赤藓红体系的吸收、荧光和共振Rayleigh散射光谱及其分析应用研究
Science in China. Series B, Chemistry Pub Date : 2007-10-20 DOI: 10.1360/ZB2007-37-5-453
王剑, Sub 刘忠芳, Sub 刘绍璞, Sub 刘江涛, 申伟 Sub, Sub 伊奥尔
{"title":"铜(II)-氟喹诺酮类抗生素螯合物与赤藓红体系的吸收、荧光和共振Rayleigh散射光谱及其分析应用研究","authors":"王剑, Sub 刘忠芳, Sub 刘绍璞, Sub 刘江涛, 申伟 Sub, Sub 伊奥尔","doi":"10.1360/ZB2007-37-5-453","DOIUrl":"https://doi.org/10.1360/ZB2007-37-5-453","url":null,"abstract":"在pH 4.2~5.0的Britton-Robinson 缓冲溶液中, 环丙沙星(CIP), 诺氟沙星(NOR), 氧氟沙星(OF), 左氧氟沙星(LEV), 洛美沙星(LOM)和司帕沙星(SPA)等氟喹诺酮类抗生素(FLQs) 能与铜(II)形成螯合阳离子, 它们能进一步与赤藓红(Ery)阴离子通过静电引力和疏水作用形成FLQs:Cu(II): Ery为1:1:1的离子缔合物. 此时, 能引起吸收光谱的变化, 并发生明显的褪色作用, 最大褪色波长均位于526 nm处, 反应具有较高的灵敏度, 除NOR的摩尔吸光系数( e )较低外, 其余5种抗生素的 e 值均大于1.0×10 5 L·mol -1 ·cm -1 , 而且LOM和OF体系的 e 值均大于3×10 5 L·mol -1 ·cm -1 , 而SPA的e 值高达7.22×10 5 L·mol -1 ·cm -1 , 可用于这类药物的分光光度测定. 离子缔合反应还导致赤藓红的荧光猝灭, 反应也具有高灵敏度, 上述6种FLQs药物的检出限在7.1~12.2 μg·L -1 之间, 为荧光猝灭法测定μg·L -1 级FLQs创造了条件. 离子缔合反应更能导致共振瑞利散射(RRS)的显著增强, 并产生新的RRS光谱. 六种药物的反应产物具有相似的光谱特征, 最大散射波长均位于566 nm处, 并在333 nm和287 nm处有2个较小的散射峰. 在一定条件下散射增强(ΔI)与药物浓度成正比. RRS法较褪色分光光度法和荧光猝灭法具有更高的灵敏度, 对不同的FLQs药物的检出限在1.7 μg·L -1 至3.1 μg·L -1 之间, 更适于痕量的FLQs测定. 研究了反应产物的吸收、荧光和RRS光谱特征, 适宜的反应条件及分析化学性质, 结合量子化学计算方法讨论了离子缔合反应的历程及对光谱特征的影响, 并研究了RRS法 的选择性及分析应用.","PeriodicalId":49128,"journal":{"name":"Science in China. Series B, Chemistry","volume":"19 1","pages":"453-462"},"PeriodicalIF":0.0,"publicationDate":"2007-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76836479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Meso-四(对-酰氧基苯基)钴、镍卟啉液晶的性质 Meso-四(对-酰氧基苯基)钴、镍卟啉液晶的性质
Science in China. Series B, Chemistry Pub Date : 2007-08-20 DOI: 10.1360/ZB2007-37-4-329
柳巍, 师同顺
{"title":"Meso-四(对-酰氧基苯基)钴、镍卟啉液晶的性质","authors":"柳巍, 师同顺","doi":"10.1360/ZB2007-37-4-329","DOIUrl":"https://doi.org/10.1360/ZB2007-37-4-329","url":null,"abstract":"合成了6个系列12个四(对-酰氧基苯基)卟啉钴和镍配合物, 用元素分析、红外光声光谱、紫外可见光谱、质谱以及核磁共振氢谱等对其结构进行了表征, 同时利用DSC、偏光显微镜、循环伏安和表面光电压谱对其液晶性能、电化学性质、荧光性质以及表面光伏特性进行了研究. 结果表明, 有9种配合物具有液晶性质, 为六角柱状结构, 均为具有较强荧光发射性质的p型半导体. 相变温度最低的是四(对-十八酰氧基苯基)卟啉镍, 为-22.54℃.","PeriodicalId":49128,"journal":{"name":"Science in China. Series B, Chemistry","volume":"94 1","pages":"329-334"},"PeriodicalIF":0.0,"publicationDate":"2007-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75381572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Pd/C气体扩散电极电化学降解4-氯酚的比较研究 Pd/C气体扩散电极电化学降解4-氯酚的比较研究
Science in China. Series B, Chemistry Pub Date : 2007-08-20 DOI: 10.1360/ZB2007-37-4-408
王辉, 王建龙
{"title":"Pd/C气体扩散电极电化学降解4-氯酚的比较研究","authors":"王辉, 王建龙","doi":"10.1360/ZB2007-37-4-408","DOIUrl":"https://doi.org/10.1360/ZB2007-37-4-408","url":null,"abstract":"分别采用氢气还原法和甲醛还原法制备了Pd/C催化剂, 利用XRD、TEM及XPS对催化剂进行了表征, 并由催化剂制备成Pd/C气体扩散阴极, 采用先通氢气后通空气的方式在隔膜电解体系中对4-氯酚进行降解, 比较了不同电极体系下4-氯酚的去除效果. 结果表明, 制备的Pd/C气体扩散阴极既对4-氯酚具有还原脱氯作用(通入H 2 时), 又能够促进O 2 还原生成H 2 O 2 (通入O 2 时), 它们对4-氯酚的去除效果要好于不掺杂Pd的气体扩散阴极. 使用氢气还原法制备出的Pd/C催化剂中Pd表面的活性点比甲醛还原法制备出的要多, 电极稳定性好, 反应60 min后 4-氯酚转化率和脱氯率接近100%, 120 min后阴极室COD去除率为87.4%.","PeriodicalId":49128,"journal":{"name":"Science in China. Series B, Chemistry","volume":"62 1","pages":"408-414"},"PeriodicalIF":0.0,"publicationDate":"2007-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85637337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
自然(非灭菌)环境白腐真菌降解活性艳红染料 自然(非灭菌)环境白腐真菌降解活性艳红染料
Science in China. Series B, Chemistry Pub Date : 2007-08-20 DOI: 10.1360/ZB2007-37-4-402
高大文, 文湘华, 钱易
{"title":"自然(非灭菌)环境白腐真菌降解活性艳红染料","authors":"高大文, 文湘华, 钱易","doi":"10.1360/ZB2007-37-4-402","DOIUrl":"https://doi.org/10.1360/ZB2007-37-4-402","url":null,"abstract":"采用碳氮摩尔比分别为56/2.2和28/44的液体培养基, 进行了白腐真菌在非灭菌环境条件下对活性艳红染料的脱色实验. 结果显示, 在非灭菌环境下, 限氮液体培养基(C/N 摩尔比为56/2.2)中的白腐真菌对活性艳红具有很高的脱色率, 脱色率最高达到92%; 而限碳液体培养基(C/N摩尔比为28/44)很容易感染葡萄球菌等细菌, 从而使脱色反应停止. 而且, 感染细菌的体系pH变化很大, 脱色第4天时, pH已升高到9.31, 造成这一结果的主要原因是限碳反应体系发生了染菌现象. 因此, 初步确定在非灭菌环境中, 限氮液体培养基可在一定程度上抑制细菌生长, 而限碳液体培养基很容易感染细菌.","PeriodicalId":49128,"journal":{"name":"Science in China. Series B, Chemistry","volume":"6 1","pages":"402-407"},"PeriodicalIF":0.0,"publicationDate":"2007-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75402345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
MRCI及其近似方法下C 2 分子 X 1 Σ + g , B 1 Δ g 和 B ′ 1 Σ + g 态的势能曲线 MRCI及其近似方法下C 2 分子 X 1 Σ + g , B 1 Δ g 和 B ′ 1 Σ + g 态的势能曲线
Science in China. Series B, Chemistry Pub Date : 2007-08-20 DOI: 10.1360/ZB2007-37-4-318
李安阳, 王育彬, 豆育升, 文振翼
{"title":"MRCI及其近似方法下C 2 分子 X 1 Σ + g , B 1 Δ g 和 B ′ 1 Σ + g 态的势能曲线","authors":"李安阳, 王育彬, 豆育升, 文振翼","doi":"10.1360/ZB2007-37-4-318","DOIUrl":"https://doi.org/10.1360/ZB2007-37-4-318","url":null,"abstract":"运用MRCI及其近似方法计算得到C 2 分子 X 1 Σ + g , B 1 Δ g 和 B ′ 1 Σ + g 3个电子态的势能曲线, 并以FCI方法为基准, 考察比较各种方法的优缺点. MRCI计算与FCI计算几乎不存在差别, 在FCI计算不现实的情况下, MRCI计算足以作为基准考验其他计算方法. 多种近似方法均能达到化学精度, 并提出一个有效的选择参考组态的方法, 提高MRCI计算效率的同时, 保证计算的精确性.","PeriodicalId":49128,"journal":{"name":"Science in China. Series B, Chemistry","volume":"66 1","pages":"318-323"},"PeriodicalIF":0.0,"publicationDate":"2007-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74651059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
乙烯/臭氧/水气相反应体系羟甲基过氧化氢产生机理及其动力学 乙烯/臭氧/水气相反应体系羟甲基过氧化氢产生机理及其动力学
Science in China. Series B, Chemistry Pub Date : 2007-06-20 DOI: 10.1360/zb2007-37-3-304
齐斌, 晁余涛, 陈忠明
{"title":"乙烯/臭氧/水气相反应体系羟甲基过氧化氢产生机理及其动力学","authors":"齐斌, 晁余涛, 陈忠明","doi":"10.1360/zb2007-37-3-304","DOIUrl":"https://doi.org/10.1360/zb2007-37-3-304","url":null,"abstract":"在室温(298±2 K)、大气压(1´10 5 Pa)条件下研究了乙烯/臭氧/水反应体系中羟甲基过氧化氢(HOCH 2 OOH, HMHP)产生机理及其动力学. 反应物采用长光路Fourier红外光谱(LP-FTIR)原位测定. HMHP经低温采集后利用高压液相色谱(HPLC)柱后荧光技术测定. 模式拟合得到的CH 2 O 2 +H 2 O→HMHP(R3)速率常数( k 3 )介于(1.6~6.0)×10 −17 cm 3 ·molecule −1 ·s −1 . 另外, 采用密度泛函理论在QCISD(T)/6-311+(2d,2p)//B3LYP/6-311+G(2d,2p)水平得到反应(R3)势能面及内禀反应坐标的基础上, 应用Polyrate 程序计算得到了298 K下该反应的经典过渡态理论(TST)速率常数 k TST 和正则变分过渡态理论(CVT)速率常数 k CVT , 并应用小曲率隧道效应模型(SCT)对 k CVT 进行了校正, 得到了经小曲率隧道效应校正后的速率常数 k CVT/SCT , 分别为2.47×10 −17 , 2.47×10 −17 和5.22×10 −17 cm 3 ·molecule −1 ·s −1 , 与模式拟合得到的结果基本一致.","PeriodicalId":49128,"journal":{"name":"Science in China. Series B, Chemistry","volume":"45 1","pages":"304-310"},"PeriodicalIF":0.0,"publicationDate":"2007-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86852284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
[2Fe2S]铁硫蛋白活性中心模型[Fe 2 S 2 (SR) 4 ] 2– (R= —H, —CH 3 )的局部自旋探讨 [2Fe2S]铁硫蛋白活性中心模型[Fe 2 S 2 (SR) 4 ] 2– (R= —H, —CH 3 )的局部自旋探讨
Science in China. Series B, Chemistry Pub Date : 2007-06-20 DOI: 10.1360/ZB2007-37-3-254
韦吉崇, 王燕, 居冠之
{"title":"[2Fe2S]铁硫蛋白活性中心模型[Fe 2 S 2 (SR) 4 ] 2– (R= —H, —CH 3 )的局部自旋探讨","authors":"韦吉崇, 王燕, 居冠之","doi":"10.1360/ZB2007-37-3-254","DOIUrl":"https://doi.org/10.1360/ZB2007-37-3-254","url":null,"abstract":"为了检验Davidson和Clark的局部自旋原理对铁硫蛋白簇合物的可行性, [Fe 2 S 2 (SR) 4 ] 2– (R= —H, —CH 3 )模型被选为研究对象. 该目的可通过计算这些体系的局部自旋期望值〈 S A · S B 〉, 〈 S A 2 〉和 m A , 并讨论它们与Heisenberg自旋模型(HSM)和Noodleman对称破缺理论之间的联系来实现. 在具体的计算中采用了自旋非限制Hartree-Fock(UHF)和自旋极化密度泛函(Spin-polarized DFT)方法, 同时比较它们的计算质量. 此外, 采用多种方案计算了它们的交换耦合常数, 并同前人的结果作了比较.","PeriodicalId":49128,"journal":{"name":"Science in China. Series B, Chemistry","volume":"1 1","pages":"254-260"},"PeriodicalIF":0.0,"publicationDate":"2007-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75195950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
355 nm光照下联苯与HNO 2 的交叉反应机理 355 nm光照下联苯与HNO 2 的交叉反应机理
Science in China. Series B, Chemistry Pub Date : 2007-06-20 DOI: 10.1360/ZB2007-37-3-261
黄丽 张仁熙 顾丁红 李萍 董文博 侯惠奇
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