JDN-Ⅱ熔剂对A356合金熔体的净化作用与机制

研究了一种低熔点玻璃熔剂——JDN-Ⅱ熔剂．试验结果表明，JDN-Ⅱ熔剂特别适用于高温A356合金熔体的覆盖保护和净化．当JDN—Ⅱ熔剂的加入量ω=0．03时，对A356合金有着覆盖保护和净化的明显效果：当熔体温度t=857℃时，铝熔体的氢含量C仅为2．6μL／g；当t=-750μ时，C降至0．7μL／g．文中还考察了该种玻璃熔剂的净化作用机制．     

稀土熔剂对铝熔体的覆盖保护作用

分别采用稀土JDN-I熔剂、C2Cl6和市售三合一熔剂B对A00纯铝熔体进行净化,获得各种熔剂膜．通过对上述熔剂膜进行扫描电镜、电子探针、能谱、X射线、X射线荧光等测试和分析得知,稀土熔剂在对铝熔体的净化过程中产生两层保护膜,接触铝熔体的内层由新型的条状纤维组织编织成,致密、韧性很好;接触空气的外层则完全由结晶态物质构成．而其他熔剂膜则没有上述特点．因而,稀土熔剂对纯铝熔体具有覆盖保护和降低熔损的作用．     

浇注温度对合金熔体冷却规律和半固态组织的影响

介绍了一种实验室自主研发的轻合金半固态浆料制备设备--锥桶式流变成形机(TBR),该设备利用刻有凸纹和沟槽的内、外锥桶的相对转动,使合金熔体在凝固过程中受到剧烈的剪切搅拌,从而获得合金半固态浆料.对TBR工艺的传热模型进行了推导,以A356为实验材料得出制备的A356铝合金半固态浆料温度与浇注温度的关系式,同时分析了不同浇注温度下合金熔体的冷却规律和获得的半固态组织形貌.结果表明,适当降低A356合金熔体的浇注温度可以延长初生固相受到的剪切时间和增加剪切次数,从而获得细小、均匀的半固态组织.当浇注温度为640℃时,初生固相平均晶粒尺寸为68μm,形状因子为0.82.     

新型细化剂AlTiBRE中间合金的纯净化处理效果研究

采用铝熔体熔剂净化技术对Al5Ti1B0.5RE中间合金细化剂熔体进行净化处理试验,优化出合适的排杂熔剂及其处理工艺,并采用OM、SEM、EDAX等进行夹杂物及细化相粒子的存在形态和成分分析.结果表明,XHJ1熔剂的净化效果好,与未净化的相比,除杂率达82.4%.当XHJ1熔剂加入量2%,处理温度750℃时细化剂中含杂量少,夹杂物数量也少、尺寸细小且弥散分布.有效的净化对改善细化剂中细化相粒子的分布形态起重要作用,即经净化后细化相粒子TiAl3分布更为均匀且多呈细小块状、平均尺寸11.16μm,TiB2相粒子呈疏松状均匀分布、平均尺寸3.28μm,此外还揭示了其改善的原因.     

羟胺二磺酸盐磺化水解生成铵盐的反应过程 II.胺基磺酸盐水解反应动力学

研究了胺基磺酸盐水解反应动力学 ,分析了氢离子对水解反应的催化作用以及水解的盐效应 ,在所研究的离子强度范围内 ,胺基磺酸盐的水解反应呈负盐效应。胺基三磺酸钾 ( NTS)水解反应动力学方程为 :dc NTSdt =k NTSc NTSc H+ ,在 30°C～ 67°C、离子强度 I=0 .0 5 mol/L时 ,k NTS=3.5 77×1 0 9e-5.460× 10 4 / RTL/( mol· s) ;胺基二磺酸钾 ( IDS)的水解反应动力学方程为 :- dcIDSdt=k IDSc H+ c IDS,在32°C～ 72°C、离子强度 I=0 .1 0 mol/L时 ,k IDS=1 .40 5× 1 0 17e-1.0 65× 10 5/ RTL/( mol· min) ;胺基一磺酸钾 ( SA)的水解反应动力学方程为 :- dc SAdt=k SAc H+ c SA,在 5 0°C～ 84°C、离子强度 I=0 .0 5 mol/L时 ,k SA=7.964× 1 0 17e-1.2 77× 10 5/ RTL/( mol·min)     

羟胺二磺酸盐磺化水解生成铵盐的反应过程Ⅱ. 胺基磺酸盐水解反应动力学

研究了胺基磺酸盐水解反应动力学,分析了氢离子对水解反应的催化作用以及水解的盐效应,在所研究的离子强度范围内,胺基磺酸盐的水解反应呈负盐效应.胺基三磺酸钾(NTS)水解反应动力学方程为(dcNTS)/(dt)=kNTScNTScH+,在30°C～67°C、离子强度I=0.05mol/L时,kNTS=3.577×109e-5.460×104/RTL/(mol*s);胺基二磺酸钾(IDS)的水解反应动力学方程为-(dcIDS)/(dt)=kIDScH+cIDS,在32°C～72°C、离子强度I=0.10mol/L时,kIDS=1.405×1017e-1.065×105/RTL/(mol*min);胺基一磺酸钾(SA)的水解反应动力学方程为-(dcSA)/(dt)=kSAcH+cSA,在50°C～84°C、离子强度I=0.05mol/L时,kSA=7.964×1017e-1.277×105/RTL/(mol*min).     

排杂熔剂净化对A356铝轮毂处理效果的影响探讨

探讨了排杂熔剂净化处理对汽车铝轮毂A356铝合金的冶金质量和性能的影响作用.结果表明,在汽车轮毂生产的熔炼阶段,用实验熔剂Ⅱ净化明显提高了汽车铝轮毂的冶金质量,其除杂率及气孔降低率分别达到45.32%和98%,二次枝晶间距减少了23.84%,削弱了冶金缺陷的有害作用;与常规熔剂净化相比,用实验熔剂Ⅱ处理后,A356铝合金(铸态)在强度提高16.06%的同时,伸长率还提高了69.23%,明显提高了汽车铝轮毂的力学性能.     

固溶温度对薄板细晶2A97铝锂合金强化机制的影响研究

固溶温度影响晶粒尺寸小于10 μm的薄板细晶2A97合金的强化机制,在固溶时间相同条件下,540 °C固溶温度得到的2A97合金时效峰值抗拉强度比510 °C的低40 MPa. 为了解释这一现象,利用X射线衍射仪、扫描电子显微镜和透射电子显微镜等表征方法,分别从固溶强化、晶界强化、位错强化、析出强化等强化机制的角度,对固溶温度影响2A97合金强化机制的原因进行定量分析. 研究发现,相对于510 °C,固溶温度540 °C时合金晶粒长大明显,回复再结晶程度高,位错密度降低,晶界无析出带变宽,这些影响导致合金性能下降.     

布洛芬胶囊含量的高效液相色谱法测定

建立了测定布洛芬含量的高效液相色谱法.选用Agilent Eclipse XDB-C8柱(4.6 mm ×250 mm,5μm),Lab Alliance C8保护柱(4.6 mm×10mm),流动相为甲醇水=7525,流速1.0 mL/min,检测波长220nm,进量样20μL,柱温室温.在10.0～400μg/mL浓度范围内,线性方程为A=52.50 C+50.79,相关系数0.999 9,回收率96.0%～100.7%,RSD 0.65%～1.32%.该方法简便、准确、快速,可用于布洛芬的质量控制.     

羟胺二磺酸盐磺化水解生成铵盐的反应过程 I.羟胺二磺酸钾的磺化反应

针对湿法同时脱硫脱硝工艺 ,提出通过构造一个液相反应过程 ,将 NOx 和 SO2 溶解在溶液中生成的 NO2 -2 和 SO2 -3 经过一系列连续的液相离子反应生成有利用价值的 NH+4 ,实现资源的合理利用。在 35°C～ 74°C,离子强度为 0 .5 5 mol/L时对羟胺二磺酸钾磺化反应动力学进行了研究 ,得出反应的动力学方程为 :- dcHIDSdt =kc HON( SO3) 2 -2 · c HSO-3,其中 k=5 .5 0 9× 1 0 8· e-6.154× 10 4 / RT;在5 0°C、离子强度为 0 .31 mol/L～ 0 .65 mol/L时 ,研究了该反应的盐效应 ,结果表明该反应呈负盐效应 ,离子强度为零时 ,有最大的速率常数 k0 =0 .0 2 4 7L /( mol· min)     

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     

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