硅锰合金电阻法定硅

根据准二元合金随其中某种合金元素含量的不同,其合金电阻率发生单值变化的规律,提出了一项硅锰合金电阻法定硅的检测技术. 实验结果表明,硅锰合金中硅含量与电阻率变化的关系可表示为[Si%]=-12.51+2×107ρ-4×1012ρ2,当合金中硅的质量分数小于6%时,合金中锰铁比对其电阻率变化的影响不大,定硅误差为0.005%～0.178%. 用于电阻率测量的合金样品适合的尺寸为6.00～6.50mm、长1cm左右,可以避免试样中夹渣、裂隙等缺陷对电阻测量精度的影响.     

用同位素稀释法测定牛肝和人血清中的锌和硒

结合阴离子交换树脂分离及巯基棉分离技术,采用同位素稀释-电感耦合等离子体质谱法测量了国际比对样品CCQM-K49牛肝样品和人血清样品中的锌和硒。结果表明,对于待测元素含量较高的样品,不经分离,高倍稀释可有效减少基体的干扰;而对待测元素含量较低的样品,则必须经过分离才能准确测量。CCQM-K49牛肝样品中锌和硒的质量分数分别为(179.8±1.2)×10^-6和(2.067±0.027)×10^-6,BW3215人血清标准物质中锌的质量分数为(1.164±0.024)×10^-6,国际比对IMEP-17人血清样品中硒的质量分数(0.0780±0.0014)×10^-6,测量结果均与比对的中心值接近,符合检测的要求。     

Al对HP40合金室温力学性能的影响

采用中频感应炉熔炼的方法制取样件.用光学显微镜分析在HP40合金中加入质量分数为5%～10%的Al元素时,各质量分数所对应的相组成和显微组织,研究在HP40合金中加入不同质量分数的Al对合金室温力学性能的影响以及合金力学性能与显微组织的关系.结果发现,加Al元素的HP40合金抗拉强度和屈服强度均随Al质量分数的增加而先升高后降低;合金的硬度随Al质量分数的增加而显著提高;合金的延伸率在Al质量分数为5%时,与未加Al的HP40合金一样未降低,而后随着Al质量分数的增加而降低.随着Al质量分数的增加,由于金属间化合物(Ni,Fe)Al的析出,合金的组织也发生了明显的变化,组织由网状结构变为枝状结构和羽毛状结构.     

嘉峪关市北部土壤重金属分布特征及评价

以嘉峪关市北部工业园区的MF化工厂为中心,展开对周边土壤的重金属元素分布特征研究并进行环境评价.通过267个样品的重金属元素分析,得出重金属元素平均w(Pb)=4.454×10-5、w(Ni)=4.389×10-5、w(Cu)=4.394×10-5、w(Cr)=6.981 7×10-4和w(Cd)=2.6×10-7,分别超出中国土壤元素背景值89%、88%、120%、1 195%和255%,表现为显著的元素富集.用地累积指数法和富集因子法结合重金属元素质量分数,对研究区土壤重金属富集程度进行评价,发现Pb和Cd主要富集在生活垃圾堆放处和废弃工厂的周围, Ni, Cr和Cu在厂区和工业废渣堆积区附近富集.     

微量Ga对SAC305锡球真圆度和色差的影响

针对Sn3.0Ag0.5Cu钎料抗氧化性差的问题,通过添加微量Ga元素,形成抗氧化合金来改善钎料的抗氧化性。分析了Ga元素质量分数为0%～0.10%时, Sn3.0Ag0.5Cu锡球(简称SAC305锡球)真圆度和色差的变化。研究结果表明:随着Ga元素质量分数的增加,锡球真圆度先减小后增加,Ga元素质量分数为0.07%时,锡球真圆度最小,为4.5×10~(-3),锡球成形度最好。锡球色差随Ga元素质量分数的增加,先增加后减小, Ga元素质量分数为0.05%时,锡球色差最大,为75.02NBS。基于微量Ga元素对SAC305锡球真圆度和色差的影响,Ga元素质量分数取0.05%～0.07%为宜。     

谢氏宽漠王无机元素和氨基酸组分的测定与分析

对谢氏宽漠王的18种无机元素和18种氨基酸组分进行了分析测定,结果表明:该甲虫含有12种必需微量元素,在样品中的总质量分数达826.93×10-6;蛋白质在样品中的质量分数为49.88×10-2,其中必需氨基酸在蛋白质中的质量分数为0.501.亮氨酸、缬氨酸、甘氨酸、谷氨酸等含量十分丰富,缬氨酸含量突出,在样品中的质量分数高达10.32×10-2.本研究为谢氏宽漠王的组成成分研究提供了基本资料,为进一步探讨其利用价值提供参考.     

元素比值法用于吸烟过程的元素迁移研究

采用元素比值法,以K作为参比元素,估算了某品牌香烟在吸烟过程中的元素迁移情况。通过收集真人吸烟前后的烟草和烟灰样品,测量了香烟中Cu,Fe,Zn和Hg,Cd,As,Pb,Cr,Ni,共9个元素在香烟和烟灰中的质量分数。利用在吸烟过程中稳定存在于烟草内的K作为参比元素,计算出吸烟导致的更大剂量地迁移进入人体的元素。结果表明,Cu元素迁移量最大,烟草中的Cu的质量分数为50.50×10-6,其中的83.3%随烟气进入气相,可能起到补充吸烟者体内元素的作用。有害元素中,Pb在烟草中的质量分数较大,为3.50×10-6;随烟气迁移的比例也大,达62.1%。其次为As和Cd,它们在烟草中的质量分数分别为0.536×10-6,0.500×10-6;随烟气迁移的比例分别是95.4%,57.3%。这三种元素应该是烟草减害研究的目标。     

等离子体温度和谱线强度综合校准的CF-LIBS定量分析合金成分

合金成分直接决定其机械性能和应用领域,对合金中各元素含量的准确、快速检测,对于冶金生产质量控制和材料分类意义重大.本文提出了一种基于等离子体温度和谱线强度综合校准的自由定标激光诱导击穿光谱(CF-LIBS)定量分析方法,选用一个与待测样品基质相同的标准样品,通过二阶迭代计算来对比不同等离子体温度和谱线强度校准系数所对应的元素含量标准误差和,寻找最小标准误差和,优化等离子体温度和次量元素谱线强度校准系数,从而建立定量分析模型,实现对待测样品中主次量元素含量的精确定量分析.基于铜铅合金的检测结果表明,本方法对样品中主量元素Cu,Zn和次量元素Pb的相对测量误差分别为4.4%,6.2%和17.7%,远优于常规CF-LIBS方法.本文提出的新方法有助于推进CF-LIBS技术在冶金生产质量监控和材料鉴别分类中的应用.     

电池包用6061铝合金型材成分与挤压成型性关系

由于现有6061铝合金挤压成型性及力学性能较差,在实际生产中应用范围受限,通过改变合金成分开发新型6061铝合金,将Si的质量分数调整至国标上限0.73%～0.80%,Mg的质量分数调整至国标下限0.82%～0.90%,同时分别设计了多细晶元素（Mn+Cr的质量分数为0.40%）与少细晶元素（Mn+Cr的质量分数为0.14%）两种配比方式,分别命名为6061-A铝合金和6061-B铝合金。通过观察微观组织、测试力学性能、调整挤压速度,研究6061-A铝合金和6061-B铝合金的力学性能、挤压成型性。结果表明,6061-A铝合金挤压成型性更好,同时经（175±5）℃×8 h热处理后,型材屈服强度达到312 MPa,抗拉强度达到325 MPa,伸长率为9%,均高于标准要求。     

Pt/WO_3/ZrO_2催化四氢糠醇氢解反应的失活研究

通过分步浸渍-焙烧法制备得到一种铂钨锆复合氧化物(Pt/WO_3/ZrO_2)催化剂,通过连续流动固定床反应器考察该催化剂催化不同水含量的四氢糠醇(THFA)溶液氢解反应的活性与稳定性。反应前后的催化剂采用N_2物理吸附-脱附、X线衍射(XRD)和NH_3程序升温脱附等技术进行表征,用电感耦合等离子体发射光谱仪(ICPAES)测量反应余液中的W元素流失量。结果表明:当反应液中水质量分数从20%增加至80%时,四氢糠醇氢解转化率翻了一倍,高达到88. 3%;过多的水会降低催化剂的稳定性,当反应液中水质量分数为80%时,四氢糠醇转化率在150 h内下降了75%。铂钨锆复合氧化物催化剂氢解反应过程中存在W流失,水质量分数为80%时达到最大流失量(9. 832 4×10~(-5));当反应液pH=7. 5、还原温度200℃时,反应余液的W流失量(6. 881×10~(-6))最小。     

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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