ICP-AES法同时测定高纯碳酸锂中11种杂质元素

研究了用ICP-AES法同时测定高纯碳酸锂中11种杂质元素Al、Ba、Cu、K、Na、P、Pb、Ca、Fe、Mg、Mn的分析方法.确定了方便快速测定高纯碳酸锂中11种杂质元素的条件.该方法的回收率为93.3％～107.2％,RSD小于6.1％.     

利用超重力富集和分离Sn-3％Fe熔体中的杂质元素铁

在粗锡精炼过程中引入超重力场,运用超重力技术研究Sn-3％Fe(质量分数)熔体中杂质元素铁在超重力场中的定向富集和过滤分离的规律,达到提纯净化粗锡的目的.结果表明,对于超重力场G=500以10℃·min-1冷却速率凝固后的Sn-3％Fe熔体,超重力场极大强化富铁相在粗锡熔体中的沉降运动,使先析出富铁相全部富集到试样的下部区域,上部几乎找不到富铁相颗粒.下部尾锡中的铁质量分数达到4.817％,而上部精锡中的铁质量分数降低到0.036％,精锡中铁的脱除率高达98.78％.在超重力场中过滤的Sn-3％Fe熔体可实现富铁相杂质和精锡液的有效分离,当重力系数大于30时,精锡的回收率随重力系数的增大而提高.在超重力场G=100,240℃条件下,Sn-3％Fe熔体过滤1 min后,精锡液几乎全部被分离到坩埚底部,富铁相杂质被截留在过滤碳毡上部,下部精锡中找不到富铁相杂质的颗粒,精锡中铁质量分数降至0.253％,富铁渣中铁质量分数高达11.528％.精锡中铁的脱除率高达91.44％,超重力场中精锡的回收率高达82.69％.     

必特螺旋霉素的工业结晶过程

以未知杂质为考察的着重点,探索了25℃下必特螺旋霉素最佳结晶时的pH以及同一pH下温度对工业结晶的影响。利用高效液相色谱对结晶产品进行检测,并用外标法对必特螺旋霉素中各部分杂质进行了详细的分析,通过对比结晶过程有效组分和总未知杂质对螺旋霉素的选择性系数,在兼顾有效组分含量合格和杂质质量分数最低的前提下,确定最优结晶终点pH为7.5~8.0,最优结晶温度为25~35℃。该方法首次以未知杂质的含量变化来探索必特螺旋霉素结晶的规律,工业上便于实施,有利于指导工业生产。     

3N碲还原熔炼-扒渣提纯法制备4N碲

为了满足碲的高端应用,开展了以3N纯度(即质量分数为99.9%)粗碲为原料,制备4N碲的工艺条件和中试研究,并采用等离子光谱仪(ICP)对样品进行了测试分析,确定了一种3N碲还原熔炼-扒渣提纯法制备4N碲的工艺方法:将1 %的还原剂与50目(300 μm)3N粗碲混匀,在700℃下还原焙烧1 h;加入0.4%的造渣剂,搅拌造渣15 min;粗碲杂质元素与造渣剂结合形成上浮渣,多次刮除至再无浮渣产生;将除渣后的碲熔浆倾入石墨模中铸锭,得到碲锭产品.该产品碲的质量分数≥99.998%,杂质元素总的质量分数＜15×10-6,每种杂质元素的质量分数＜5×10-6,完全符合4N纯度精碲要求.中试结果表明,该工艺流程简单,工艺周期短,成本低廉,环境污染小,是一种可规模化生产4N碲的新工艺.     

毛细管柱色谱法测定食品防腐剂山梨酸和苯甲酸的探讨

该文采用AT.食品添加剂分析专用毛细管柱(30m×0.53mm×1.00 μ m),对山梨酸和苯甲酸两种常见防腐剂进行测定,实验表明,通过对色谱条件的优化,在柱温190℃,载气流速160kPa条件下,在3.5min内实现基线分离,各组分分离良好,分析速度快,准确度高,山梨酸回收率为88.04％～94.71％,RSD≤4.3％;苯甲酸回收率为94.02％～104.47％,RSD≤1.4％.     

微波溶样-ICP法测定海绵铁中主要杂质的含量

采用微波溶样法溶解较难溶的海绵铁，用ICP测定其中的氧化钙、氧化镁、氧化铝、二氧化硅、二氧化钛和磷等主要杂质的含量。探索了微波溶样条件、分析谱线的选择以及铁基体的干扰及校正。试验表明：微波溶样-ICP法测定海绵铁中氧化钙、氧化镁、氧化铝、二氧化硅、二氧化钛和磷等主要杂质的含量，精密度为RSD％≤3％，回收率在95～105％之间；微波溶样-ICP法测定海绵铁中各元素的含量是一个快速、简便、实用的分析方法。     

白芷愈伤组织中总香豆素的提取与测定

建立了白芷愈伤组织中总香豆素质量分数的测定方法,同时优选利用超声提取白芷愈伤组织中总香豆素的最佳工艺.采用L9(34)正交实验对乙醇体积分数、超声时间、超声温度以及溶液pH等因素进行研究,确定超声提取的最适条件.以欧前胡素为指标性成分,检测波长为300 nm,利用紫外-可见分光光度法检测白芷愈伤组织中总香豆素的质量分数.结果表明,利用超声提取白芷愈伤组织中总香豆素的最适奈件为:乙醇体积分数为60％,pH为9,超声温度70℃,超声时间30 min.欧前胡素的质量浓度在3.0～30.0μg/mL (R=0.999)内与吸光度呈良好的线性关系,平均加样回收率为98.03％,RSD=2.4％(n=3).该方法操作简单,结果准确,可用于白芷愈伤组织中总香豆素的质量分数测定.利用该方法对白芷愈伤组织和白芷药材进行同时提取测定,结果表明白芷愈伤组织中总香豆素的质量分数是白芷药材中的9.7倍.     

食用植物油中生育酚含量测定方法优化及分析

采用高效液相色谱法测定了8种24个植物油样本中生育酚的含量,并对生育酚的提取条件进行优化.在室温下,以甲醇为溶剂,采用超声法进行提取,料液比为1∶1.25,提取3次,每次20min,采用液相色谱方法进行分析.结果表明:该方法在生育酚质量浓度为0.05 ～ 1.00 g/L时,相关系数R2可达到0.999 2 ～0.999 4,线性关系良好;检出限分别为α-生育酚0.5 mg/L,γ-生育酚2.0mg/L,δ-生育酚1.2 mg/L;三水平加标样品的平均回收率为92.1％ ～99.8％,相对标准偏差(RSD,n=3)为2.5％ ～8.5％.在8种植物油中,葵花籽油中α-生育酚的质量分数较高,可达4.2349×10-4,大豆油的β/γ-生育酚、δ-生育酚及总生育酚的质量分数较高,分别为7.3713 ×10-4,1.621 5×10-4,9.883 6×10-4.     

异辛酸镍的电化学合成

研究异辛酸镍的电化学合成,考察支持电解质氢氧化钠浓度、氯化钠浓度、电流密度和温度对合成过程中的影响,确定各个影响因素的最佳条件。并通过溶解过滤洗涤对产物进行除杂,再通过蒸馏分离有机溶剂获得产品。使用红外光谱定性分析确定产物结构。通过稀盐酸溶解产物来对产品中的镍质量分数进行分析。最后对电解液进行重复循环利用。研究结果表明:在最佳实验条件下,即氢氧化钠浓度为0.2 mol/L、氯化钠浓度为2.0 mol/L、电流密度为2 380 A/m2和温度为60℃时,产率在95%以上,产物镍金属质量分数在10%以上,技术指标符合Q/FMH02—2011标准要求。通过红外光谱表征,确定产物为异辛酸镍。通过电解液的循环利实验,5次循环实验中产品中的镍质量分数、产率以及产品杂质钠质量分数均比较稳定,可以实现电解液的循环使用。     

木棉叶中多糖含量的测定

黎药木棉叶用石油醚除去脂溶性杂质，用水提醇沉法得海南木棉叶的多糖，采用苯酚-硫酸比色法对多糖含量进行了测定．测得木棉叶的多糖质量分数为0．72％，加样平均回收率为101．1％，相对标准偏差RSD为1．76％．     

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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