大颗粒氯化钾制备试验研究

以提高氯化钾颗粒粒径为目的,在已有溶解度数据基础上,采用目测法结合原子吸收绘制、拟合得到氯化钾超溶解度曲线,从而得到介稳区上下限;采用不同温度下饱和氯化钾进行了自然冷却结晶、冷—热耦合结晶及冷—热耦合结晶最佳配比的试验研究。结果表明:采用60℃与35℃的KCl溶液以1∶3的体积比进行混合,经自然冷却结晶,得到晶体中2.5 mm以上晶粒百分比为73.48,最大粒径为3 mm,为提高钾肥利用率提供了一种新途径。     

扶桑花中石油醚溶物的结构测定和抗生育活性研究

扶桑花中的石油醚溶物经活性追踪,得到一白色针状结晶．分析表明,该结晶为扶桑甾醇氧化物,具显著的抗生育活性．     

复合结晶银催化剂的制备及催化性能

应用超声波电解法制备了La2O3/Ag复合银催化剂.利用SEM,XRD等手段对负载不同氧化镧含量的催化剂研究结果表明:电解过程中嵌入少量氧化镧,结晶银的晶体结构得到保持,催化剂的抗烧结性能得到显著提高.以丙二醇选择性催化氧化为反应体系,比较了1%La2O3/Ag复合结晶银和工业结晶银催化剂的催化活性和稳定性,实验结果表明:复合结晶银催化剂的低温氧化活性受到部分抑制,但是催化剂稳定性和反应选择性得到显著提高.     

盐酸赛庚啶的结晶研究

目的:研究盐酸赛庚啶的晶型.方法:运用自然结晶和快速结晶方法制备盐酸赛庚啶的晶型,经X射线衍射分析法(PXRD)、差示扫描热分析法(DSC)、热重分析(TG-DTA)等方法对盐酸赛庚啶的多种晶型进行表征.结果:通过调节溶剂和结晶方式得到盐酸赛庚啶的4种晶型,经检测发现盐酸赛庚啶溶解于热的甲醇溶液自然结晶得到晶型Ⅰ,快速结晶得到晶型Ⅱ;当溶剂采用无水乙醇时得到晶型Ⅲ和Ⅳ.结论:Ⅰ~Ⅳ型盐酸赛庚啶的理化性质存在明显差异,最终以甲醇为溶剂,快速结晶制备出了新晶形Ⅱ,晶形Ⅱ熔点最高、融化吸收热量大,具有较好的稳定性,并且晶型纯度高.     

废铅膏湿法浸出强化结晶的影响规律研究

针对乙酸-柠檬酸钠工艺浸出制备的柠檬酸铅前驱体颗粒较小和形貌不均一的问题,以废铅酸电池主要成分废铅膏为原料,浸出制备的浆料通过水浴条件进行结晶强化处理,并采用分析纯试剂模拟废铅膏的主要化学成分进行对比研究.模拟铅膏与废铅膏浸出后在水浴结晶强化处理下得到的柠檬酸铅结晶产物形貌和过滤性能规律基本相同.相比于模拟铅膏,废铅膏水浴结晶强化处理后制备的重结晶产物形貌也更为均一,粒径介于100~200μm,过滤性能得到提高,表明水浴结晶强化过程更有利于废铅膏湿法浸出结晶.     

低含量丙三醇共聚改性PET的非等温结晶特性

采用差示扫描量热法(DSC)对聚对苯二甲酸乙二酯(PET)及不同含量丙三醇(GL)共聚改性PET进行测试.并利用不同动力学模型对DSC数据进行非等温结晶研究,分析对比的结果表明:结合Avrami和Ozawa方程可以较好地描述PET及GL共聚改性PET的非等温结晶行为,得到共聚改性PET聚酯的结晶速率随GL含量的增加而先提高后降低;通过计算Ziabicki结晶能力参数,得到结晶能力随GL含量的提高而先提高后降低;通过Kissinger方程计算结晶活化能,得到结晶活化能随GL含量的提高而先减小后增加.低含量GL共聚改性PET随支链的增加结晶速率和结晶能力先提高后降低,在所讨论的范围内,GL900-PET的结晶速率最快,结晶能力最强.     

铬酸钠碱性液中氢氧化钠的高效分离研究

为实现铬铁矿碱溶得到的铬酸钠碱性液中Na2CrO4和NaOH的高效分离,研究了铬酸钠碱性液体系的蒸发结晶过程工艺,通过条件优化得到:碱性液的蒸发至碱度为47.67%(w%),结晶温度为40℃时,保温1 h后过滤,可以实现铬酸钠与氢氧化钠的有效分离。     

结晶法分离蒜头果油中神经酸溶剂选择研究

经过对蒜头果油的初步处理得到粗品神经酸．而后对粗品神经酸在三种单组分溶剂中的结晶分离提纯进行了研究.同时考察了混合溶剂对结晶分离的影响,通过GC～MS对结晶成分的分析,结果表明,石油醚、无水乙醇结晶分离较为理想。而汽油较差;混合溶剂能改善结晶分离效果,并且以石油醚和无水乙醇混合溶剂为最佳．     

结晶法精制玉米须中植物甾醇

植物甾醇具有重要的食用和药用价值,研究了农业废弃物玉米须中植物甾醇的提取结晶工艺.玉米须经过皂化处理后,通过超声波辅助提取,得到的粗品经氯仿萃取后,通过正交试验确定最佳结晶工艺条件:粗品和乙酸乙酯以1mL∶1g的料液比在0℃处理12h,可得到植物甾醇的结晶,再滴加甲醇抽滤后得到植物甾醇重结晶,纯度为92.36%±0.33%(w/w).     

X射线衍射制冷剂水合物的结晶过程分析

为使制冷剂水合物的生成高效稳定,通过制备水合物晶体,获得了水合物结晶过程的反应温度曲线.利用X射线衍射(XRD)测试装置,得到了X射线粉末衍射图谱.结合反应温度曲线,对试验样品衍射图谱进行了定量分析,对水合物结晶过程进行了分析.试验结果表明:整个结晶过程均有水合物生成,且水合物生成的最佳阶段为相变阶段.在平衡结晶温度和...     

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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