谷氨酸脱氢酶(GDH)的性质

考察了GDH催化的最适条件:40℃,pH8.5,磷酸盐缓冲液离子强度为0.25mol/L.酶活性稳定的pH范围为5.5～9.0.甘油对GDH的热变性有明显的保护作用.     

铜(Ⅱ)对蝌蚪的急性毒性研究

研究了不同温度、pH值和碱度条件下铜离子对黑斑蛙蝌蚪的急性毒性,结果表明:铜离子对蝌蚪的毒性随水温的升高明显加强,当温度为20、26、32℃时,96 h的半数致死浓度(LC50)分别为0.206、0.032、0.026 mg/L.在酸性条件下随着pH的升高,铜离子对蝌蚪的毒性降低,在碱性条件下随着pH的升高,铜离子对蝌蚪的毒性加剧,pH值为6.7、7.5、8.8时,96 h的LC50分别为0.100、0.206、0.140 mg/L;在碱度较低时,铜离子对蝌蚪的毒性随碱度的升高而降低,在碱度较高时,铜离子的毒性随着碱度的升高而增强,碱度为0.79、1.30和1.65 mmol/L时,96 h的LC50分别为0.206、0.180、0.100 mg/L.     

镉离子胁迫下4种辣椒超氧化物歧化酶-同工酶酶谱及酶活性分析

以4种辣椒为材料,分析在不同胁迫浓度和胁迫时间镉离子胁迫下,4种辣椒超氧化物歧化酶(SOD)活性及同工酶酶谱的变化.结果表明,镉离子能显著影响酶活性的变化,不同镉离子浓度胁迫下不同材料酶活性变化不同, SOD酶活性最高为对照组的1.4倍(1号品种,100 mg/L胁迫3 d),酶活性最低的为对照组的60%(2号品种,150 mg/L胁迫6 d);镉离子还能影响同工酶酶谱,不同胁迫时间和浓度对同工酶的影响不同,对1号材料的影响最为显著,能诱导出2条SOD同工酶新谱带.     

连续式泡沫分离去除水中低含量锌离子的研究

采用连续式泡沫分离法对水中的锌离子的去除进行了研究,考察了pH值、表面活性剂的浓度、溶气压力、溶气水流量、进料量和硫酸铝质量浓度等因素的影响.当水中的锌离子初始质量浓度为10 mg/L,pH值为11,采用α-烯基磺酸钠(AOS)做表面活性剂且质量浓度为15 mg/L,进料60 L/h,溶气水流量为300 L/h时,去除率可达98.37%.     

啤酒酵母菌对Pb2+与Zn2+的生物吸附规律

研究了啤酒酵母菌体对工业废水中重金属离子Pb2 ,Zn2 的生物吸附规律.实验结果表明,啤酒酵母菌体对Pb2 的吸附效果比对Zn2 的吸附效果要好;啤酒酵母菌体对铅离子和锌离子的吸附作用与pH值密切相关,最佳的pH值范围均是4～6.体系pH=4时,啤酒酵母菌对Pb2 的吸附量最大,为98.20mg/g;在pH=5.5时,啤酒酵母菌对Zn2 的吸附量最大,为13.89mg/g.在初始铅、锌离子浓度均为1mmol/L的水溶液中,吸附时间为15min即达到吸附平衡,该吸附过程具有一级动力学反应特征.     

水中二溴海因在紫外辐照下的分解和副产物的形成机理

研究1,3-二溴-5,5-二甲基海因(DBDMH)水溶液中的有效溴、溴离子和溴酸根离子在紫外(UV)辐照下的转化过程,并探讨pH、光照波长和氨氮等因素对次溴酸溶液的光促歧化反应的影响.研究结果表明:普通消毒剂量的DBDMH水溶液(质量浓度为3.2 mg/L)紫外辐照5 min后可产生质量浓度较大的溴酸根离子(>25.9 μg/L);溴酸根离子是次溴酸光促歧化反应的中间产物;在实验条件下,紫外光波长越短,越有利于有效溴的光解和溴酸根的 生成,而pH的影响较小;氨氮通过与有效溴反应形成溴氨抑制溴酸根离子的生成.     

白毒鹅膏菌胞外漆酶的部分酶学性质研究

从威海市玛珈山上获得白毒鹅膏菌，在对其产酶条件研究的基础上，研究了pH值、温度、无机离子对白毒鹅膏菌漆酶活性和稳定性的影响，测定了漆酶的Km值。结果表明：Ba^2＋、Cu^2＋、、SO4^2-离子对漆酶有激活作用，而Ag^2＋、Cl^-、Fe^3＋离子则有抑制作用，该酶最适pH为4.6，在pH 5.0-5.4表现出较强的稳定性；最适反应温度为20℃，低于60℃时有较好的热稳定性；以邻联甲苯胺为底物的表观Km值为66.7μmol/L。     

假单胞菌593多铜氧化酶CopA的漆酶活性研究

从假单胞菌593中克隆出多铜氧化酶copA基因,并将其转入大肠杆菌BL21(DE3) p Lys S过量表达和纯化.纯化的CopA蛋白展示出漆酶活性,针对漆酶的3种底物ABTS、DMP、SGZ,CopA的最适反应pH分别是3. 5、7. 5和7. 5,最适反应温度分别是50℃、50℃和42℃.pH稳定性和热稳定研究发现,在pH 7. 0条件下,CopA比较稳定,在温度大于42℃保存该蛋白,其活性降低较快.二价金属离子影响实验发现,CopA漆酶活性能被二价铜离子显著加强.酶动力学常数实验结果展示,CopA作用于底物ABTS,K_m为0. 281 mmol/L,V_(max)为3. 02×10~(-3)mmol·L~(-1)·min~(-1),k_(cat)为1. 8 s~(-1); CopA作用于底物DMP,K_m为0. 141 mmol/L,V_(max)为4. 54×10~(-3)mmol·L~(-1)·min~(-1),k_(cat)为2. 2 s~(-1); CopA作用于底物SGZ,K_m为0. 025 mmol/L,V_(max)等于0. 7×10~(-3)mmol·L~(-1)·min~(-1),k_(cat)为0. 87 s~(-1).     

硫酸钡比浊法的改良及其在生物冶金浸出体系硫酸根浓度测定中的应用

为改良现有硫酸钡比浊法,以适应生物冶金复杂样品浸出体系中硫酸根离子浓度的测定,探讨不同稳定剂、无水乙醇用量、Tween-80用量和酸度等对硫酸钡分散体系稳定性的影响,得到比浊法测定硫酸根离子浓度体系中的最佳条件是:无水乙醇3.0 mL,0.1 g/L Tween 1.0 mL,pH=1.0.在测量波长420 nm处,硫酸根浓度在0.1～0.8mmol/L范围内符合比尔定律.该方法的检出限为0.55 mg/L,定量限为1.82 mg/L.该方法简便快速,回收率为98.9％～101.9％,相对标准偏差为0.68％～1.90％.与GB/T 5750.5-2006国标法比较,该方法操作简便、快捷,结果可靠,在生物浸矿液硫酸根离子浓度的测定中得到较好结果.     

CdTe量子点荧光猝灭法测定铜离子的研究

以巯基乙酸为稳定剂,在水溶液中一步合成了CdTe量子点.以该量子点为荧光探针,基于荧光猝灭法对Cu2+离子进行了定量检测.考察了缓冲体系、缓冲液浓度、缓冲液pH值、反应时间、量子点浓度等多种因素的影响,在0.033mol/L、pH值为5.91的磷酸二氢钾磷酸氢二钠缓冲液中,当量子点浓度为3.8×10-4mol/L、反应时间为30min时,该方法的线性区间为2～200μg/L,检测下限为0.29μg/L.具体解释了量子点荧光猝灭,是由于价带电子激发到导带以后被表面结合的Cu2+离子捕获而产生的结果,并利用光解实验进一步验证了这一机理.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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