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151.
利用电动势法得到了牛血清白蛋白(BSA)与十二烷基硫酸钠(SDS)相互作用的结合等温线. 通过四阶导数紫外光谱法和荧光光谱法研究了相互作用过程中芳香族氨基酸残基微环境极性的变化. 通过研究发现, 随着SDS浓度的逐渐增大, SDS在BSA上的平均结合数(v)逐渐增大, 色氨酸(Trp)残基所处微环境的极性在减弱后保持基本不变, 酪氨酸残基所处微环境的极性在明显增强后稍有减弱, 苯丙氨酸残基所处微环境的极性略有增强. 结果表明, 当v由0增大到14时, SDS主要结合在BSA的Trp-213附近并逐渐形成聚集体, 从而诱导BSA由结构域ⅡA 开始逐渐展开. 此后, SDS呈正协同作用的特点与BSA 结合, v急剧增大. 当v约为302 时, SDS在BSA上的结合基本达到饱和, BSA的构象趋于稳定. 相似文献
152.
《中国化学快报》2021,32(10):3215-3220
Antibiotics such as sulfonamides are widely used in agriculture as growth promoters and medicine in treatment of infectious diseases. However, the release of these antibiotics has caused serious environmental problems. In this paper, photocatalytic oxidation technology was used to degrade sulfadiazine (SDZ), one of the typical sulfonamides antibiotics, in UV illuminated TiO2 suspensions. It was found that TiO2 nanosheets (TiO2-NSs) with exposed (001) facets exhibit much higher photoreactivity towards SDZ degradation compared to TiO2 nanoparticles (TiO2-NPs) with a rate constant increases from 0.017 min−1 to 0.035 min−1, improving by a factor of 2.1. Under the attacking of reactive oxygen species (ROSs) such as superoxide radicals (O2–) and hydroxyl radicals (OH), SDZ was steady degraded on the surface of TiO2-NSs. Based on the identification of the produced intermediates by LC–MS/MS, possible degradation pathways of SDZ, which include desulfonation, oxidation and cleavage, were put forwards. After UV irradiation for 4 h, nearly 90% of the total organic carbon (TOC) can be removed in suspensions of TiO2-NSs, indicating the mineralization of SDZ. TiO2-NSs also exhibits excellent stability in photocatalytic degradation of SDZ in wide range of pH. Even after recycling used for 7 times, more than 91.3% of the SDZ can be efficiently removed, indicating that they are promising to be practically used in treatment of wastewater containing antibiotics. 相似文献
153.
154.
以高校基础化学实验"从海带中提取碘""三草酸合铁(Ⅲ)酸钾的制备"为例,分别探讨了微视频技术在化学基本操作实验和综合设计型实验中的具体应用;此外,举例说明利用Flash软件制作的虚拟微视频可以在仪器分析实验中清晰地再现仪器真实操作中的每一个步骤,弥补了学生在实验前无法实际操作仪器的不足。实践证明,微视频技术的应用,丰富了基础化学实验教学模式,增强了学生自主学习的能力和动手能力,提高了实验成功率和实验教学效果。 相似文献
155.
The reaction between salicylic acid and dialkyl phosphite was traced by electrospray ionization mass spectrometry and ^31P NMR. All reactants, unstable intermediates and products were detected. The mechanism was proposed based on ESI-MS results and ^31P NMR profiles. 相似文献
156.
1,3-丙二胺的不对称双Schiff碱异三核配合物的合成表征、晶体结构与磁性研究 总被引:1,自引:0,他引:1
合成了一种新的不对称双Schiff碱Cu(II)单核配合物Cu(HLt) (1) (H3Lt为N-3-羧基水杨醛-N'-水杨醛-缩1,3-丙二胺)及其两个异三核配合物[(CuLt)2Ni]•2.5H2O (2)和[(CuLt)2Mn]•5H2O (3), 并用元素分析、红外光谱、电子光谱对它们进行了结构表征. 用X射线单晶衍射法测定了配合物3的晶体结构, 其晶胞中每个不对称单元包含一个异三核中性分子, 在此三核分子中, 中心Mn2+离子位于[O6]的变形八面体配位环境中, 两个端基Cu2+离子位于[N2O2]的平面正方场中. 在5~300 K范围内测定了两个三核配合物的变温磁化率, 经拟合得化合物2的磁交换参数为-57.7 cm-1, 化合物3的磁交换参数为-28.5 cm-1, 表明在两个异三核配合物中, 中心M2+离子与外部Cu2+离子间存在弱的反铁磁自旋交换作用. 相似文献
157.
ShuXiaCAO JianChenZHANG MingYuNIU KuiLU XinChengLIAO YuFenZHAO 《中国化学快报》2004,15(6):652-654
N-Phosphoryl peptide libraries were constructed by transformation from homo-oligopeptide libraries, which was synthesized by self-assembly of amino acids with the assistance of phosphorus oxychloride. Electrospray ionization mass spectrometry (ESI-MS) was used to monitor the reaction. 相似文献
158.
A novel type of phosphated puerarin derivatives were synthesized through a simplified Atheron‐Todd reaction for the first time. The structure of these compounds were elucidated by IR, ESI‐MS and NMR. Moreover, the reason the dialkylphophite reagent had different chemselectivities toward different hydroxys on the puerarin was discussed. 相似文献
159.
WEI Ping-Rong JIA Lu LIU Chang-Rang FAN Yao-TingDepartment of Chemistry Zhengzhou University Zhengzhou Henan ChinaGAO SongResearch Center of Rare Earth Chemistry Peking University Beijing China 《中国化学》1994,12(6):503-508
The two complexes [Ni(oxen)Cu(L)2](ClO4)2.xH2O (L=2,2'-bipyridyl(bpy), 1,10-phenanthroline(phen)) have been synthesized, where oxen is N,N'-bis(2-aminoethyl)oxamido di-anion. The crystal structure of [Ni(oxen)Cu(bpy)2](ClO4)2.CH3OH has been determined by X-ray diffraction method. The crystal is triclinic system, space group P1 with a=12.179(1),b=12.298(2), c=11.476(2) A, a=97.57(1), B=97.52(1), 7=80.29(2), V=1669.04(67) A3, Z=2, Dcalcd=1.667 g/cm3. The structure has been refined to final R of 0.076 and Rw of 0.080, respectively. The complexes have an extended oxamido-bridged structure and consist of Ni(Ⅱ) ion in a square planar environment and Cu(Ⅱ) ion in a distorted octahedral environment. 相似文献
160.
《Electrochemistry communications》2007,9(4):569-573
A kind of mesoporous carbon spheres (MCS) containing in-frame incorporated nitrogen has been prepared by a facile polymerization-induced colloid aggregation method. As the electrode material for electric double layer capacitor (EDLC) in 5 mol/L H2SO4, the MCS products present excellent specific capacitance as 211 F/g much larger than that of the most popularly applied activated carbon at a high discharge current density of 1 A/g. Its specific capacitance can still remain 200 F/g at 20 A/g. The superior electrochemical performance of MCS is associated with the following characteristics: high specific surface area (∼1330 m2/g) contributed mainly by the mesopores, uniform pore size as large as 29 nm and moderate content of nitrogen (10 wt%), which are the requirements for ideal supercapacitors. 相似文献