硫磺中铅的快速极谱分析

提出用硫化铵-氨水-过氧化氢分解硫磺试样,在0.63 mol/L醋酸—0.60 mol/L溴化钾—0.14 mol/L盐酸羟胺—0.30 mol/L硫酸铵体系中以单扫描极谱测定微量铅的方法.铅极谱峰电位为—0.48 V(相对饱和甘汞电极).铅浓度在0.2～1μg/mL范围内与峰电流成良好的分段线性关系.检出限为0.16 ng/mL.RSD为3.6%～5.6%.加标回收率为86%～93%.此法操作快速简单,用于硫磺中铅的测定,结果满意.     

聚苏木精/氧化石墨烯修饰玻碳电极测定水样中痕量铅和镉

将玻碳电极用氧化石墨烯修饰后电聚合上苏木精聚合膜,利用该修饰电极差分脉冲溶出伏安法同时测定铅和镉.对支持电解质及其缓冲溶液、富集电位及富集时间测定条件进行了优化.在0.1 mol/L pH 3.5的NaAc-HAc缓冲液中,以此修饰电极为工作电极,在-1.1 V处搅拌富集220 s,用差分脉冲伏安法分别测定-0.58 V和-0.8V处的氧化峰电流.结果表明,该电极显著提高了铅和镉的电化学响应信号.在优化条件下,峰电流与铅和镉的浓度在0.01~1μmol/L范围内呈良好的线性关系,相关系数为0.991~0.995.检出限分别为8 nmol/L(Pb2+)和1 nmol/L(Cd2+)(S/N=3).将该法用于实际水样中痕量铅和镉的测定,回收率为92.2%~105.8%.     

锡-铜铁试剂-吐温-80体系的络合吸附波

发现在0.0052％钢铁试剂、0.002％吐温-80、1:1醋酸-醋酸铵底液(pH≈5.4)中,锡在单扫示波极谱上有良好的络合吸附波。峰电位为-0.72V(vs.SCE)。可测定1×10~(-6)-4×10~5g/ml锡含量。铅、铜、锑、铋等许多离子不干扰锡的测定,检测下限为4ng/ml。建立了示波极谱法测定食品罐头、铜合金及天然水中微量锡的方法。     

静止拟微分电位溶出法测定水体中重金属离子

本文介绍了静止拟微分电位溶出法分别对天然水、矿泉水、受污染水体中重金属离子镉、铅的测定。文中讨论了分析条件,采用了0.2mol/L HAc-NH_4Ac缓冲液作支持电解质,1×10~(-4)mol/L Hg~(2+)作氧化剂的体系。用本方法Cd~(2+)离子的最低检测限为0.08ng/mL,在0.3ng/ml-10ng/ml的浓度范围内Cd~(2+)、Pb~(2+)离子与峰高均呈现良好的线性关系。在1ng/ml的Cd~(2+)和1ng/ml的Pb~_(2+)浓度下,连续测定11次,其相对标准偏差分别为3.8％和4.9％。方法的回收率在108％到99％之间。     

单扫描极谱法同时测定酒中微量甲醛、乙醛、丙酮

提出了在0.06 mol/L氯化铵和0.08 mol/L硫酸联氨底液中,单扫描极谱法于原点电位-0.9 V(vs.SCE)起扫,在峰电位分别为-1.13 V(vs.SCE)和-1.33 V(vs.SCE)测定甲醛、乙醛,同时于原点电位-1.20 V(vs.SCE)起扫,在峰电位-1.49 V(vs.SCE)测定丙酮的方法.线性范围为0.25～20.0mg/L甲醛,0.25～16.0mg/L乙醛,0.10～20.0mg/L丙酮;最低检出浓度0.25 mg/L,0.25 mg/L,0.10 mg/L.方法简捷快速,用于酒样分析符合要求.     

松花蛋中痕量铅的方波溶出伏安法测定

用方波溶出伏安法测定松花蛋中痕量铅,在抗坏血酸存在下,以0.1 mol/L硝酸溶液为底液,玻碳电极为工作电极,测得铅的溶出峰电位是-0.48 V。峰高与铅浓度在1.00×10-4~1.00×10-6mol/L范围内呈良好的线性关系,铅的检出限为5.00×10-8mol/L,回收率为90%~108%。此法干扰较少,易于掩蔽,灵敏度较高,适用于松花蛋等食品中微量铅的测定。     

铅（Ⅱ）—Tiron络合物极谱吸附波研究

在0.56mol/L NaAc—0.04%Tiron 溶液中,铅(Ⅱ)与 Tiron 产生的络合物,在单扫描示波仪上可观察到一灵敏的极谱导数波,其峰电位为-0.49V(vs.SCE),峰电流与铅浓度在7.7×10~(-6)—6.8×10~(-6)mol/L 范围内成线性关系,检测限为3.8×10~(-(?))mol/L.应用该波测定了铜合金中的微量铅,结果良好,精密度和准确度均较满意,本文研究了形成铅-Tiron 络合物吸附波的条件,探讨了波的性质,用极谱法测定出其络合比为1:1.     

高钙食品中痕量铅的极谱测定

建立了在0.6%碘化钾-0.8%酒石酸钾钠-0.36 mol/L盐酸-0.14 mol/L磷酸-0.6%三乙醇胺-0.1%抗坏血酸底液条件下,用单扫描极谱法测定高钙食品中痕量铅的方法.试验表明,本法的线性范围为5～800 ng/mL,检出限为1.5 ng/mL,样品加标回收率为95%～107%,相对标准偏差为4.3%～8.5%.     

碳纳米管/石墨烯/铋膜修饰碳糊电极测定铅和镉

用碳纳米管(CNT)、石墨烯(GR)、铋膜修饰碳糊电极构建碳纳米管石墨烯铋膜修饰碳糊电极(CNT/GR/Bi/CPE),并用差分脉冲伏安(DPV)法测定了铅和镉的含量。在最优条件:电解质缓冲底液p H为5.5,沉积时间50 s,沉积电位-1.3 V,用碳纳米管石墨烯铋膜修饰碳糊电极(CNT/GR/Bi/CPE)同时测定Pb2+和Cd2+得线性方程分别为:IPb2+(A)=-5.8202?10-6-1.0342c(mol/L)(R=0.9978);ICd2+(A)=-3.9781?10-6-1.3651c(mol/L)(R=0.9923),线性范围分别为1~15μmol/L和2~16μmol/L,Pb2+、Cd2+的检出限分别为:6.67?10-7 mol/L;3.33?10-7 mol/L。本方法操作简单且修饰电极稳定性、重现性好易于进行检测铅镉离子。     

方波溶出伏安法同时测定废水中微量的锌、镉、铅和铜

报道了用方波溶出伏安法同时测定废水中微量锌、镉、铅和铜的一种方法.在浓度为0.15mol/L,pH=5.0的氯化铵分散体系中,温度18℃的条件下,Zn2 、Cd2 、Pb2 和Cu2 均灵敏地产生溶出峰,峰位分别为:-1.13V、-0.72V、-0.50V、-0.22V(vs,S.C.E).线性范围分别为2×10-7～2×10-5、2×10-7～2×10-5、1×10-7～2×10-5和5×10-7～5×10-5mol/L,检测限为2×10-8～2×10-7mol/L,回收率为87.7～102.4%.     

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

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     

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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