硫氰酸钠溶剂中丙烯磺酸钠的测定

本文介绍硫氰酸钠溶剂中丙烯磺酸钠的测定方法。该法先使用大孔吸附树脂去除试样中部分干扰杂质,然后在碱性介质中,以硝酸银为沉淀剂去除 SCN~-,S~(2-),SO_3~(2-)等离子的干扰,控制滤液酸浓度在1.20N HCl 以上,以防止甲酸钠和溴起反应,最后用溴量法测定滤液中的丙烯磺酸钠含量。实验结果表明当试样中硫氰酸钠含量在51%时,丙烯磺酸钠含量为0.10—0.45%,相对误差不超过±3%。该法操作较方便,数据重现性好,可供腈纶厂控制分析用。     

硫氰酸钠溶剂中甲基丙烯磺酸钠的测定

本法采用碱性介质中,硝酸银沉淀法除去SCN~-,S~(2-),SO~3(2-)等离子的干扰。控制滤液pH在0.65以下,以防止甲酸钠和溴化碘起反应,然后用溴化碘卤化法定量测定滤液中的第三单体甲基丙烯磺酸钠(SMAS)的含量。操作简便,数据重现性好,硫氰酸钠溶剂中NaSCN含量在50—52％,SMAS含量在0.025％—0.12％范围内,相对误差不超过±3％。可供腈纶厂控制分析用。     

基于图像分割的多CCD测量系统干扰去除方法

针对多电荷耦合器件(CCD)光切法物体三维形貌测量系统中杂散光干扰难以去除的问题,提出一种基于图像分割的干扰去除方法,在灰度空间进行阈值分割的同时,在图像中进行区域分割。对干扰源的分析显示,激光条纹关于玻璃底板的反射是干扰的主要来源。玻璃底板以上的部分包含条纹信息,玻璃底板以下为干扰信息存在区域。将玻璃底板在图像中的位置提取出来,利用Hough变换进行检测,求出直线方程。用该直线对测量过程中的图像进行区域划分,有效区域保留原始信息,无效区域置为零,彻底去除干扰。该方法与传统的图像滤波去除干扰的方法相比,可以在去除干扰的同时保持激光条纹的原始信息和测量数据的完整性,该方法已在多CCD三维形貌扫描仪中得到实际应用。     

离子交换纸富集-X线荧光光度法测定水样中微量银

微量银离子可用阳离子交换纤维滤纸由pH4.5 HAc-NaAc缓冲的溶液中选择地富集,重金属离子的干扰可用EDTA掩蔽,S~(2-)、S_2O_3~(2-)和CN-等的影响可预先氧化去除。滤膜用X线荧光光度测定。测量范围为5.0～50.0μg/500ml,检出限为1.0μg/500m1.     

三元固态配合物Pr(Me2dtc)3(phen)的热分解动力学研究

在无水乙醇中使用低水合稀土氯化物与二甲基二硫代氨基甲酸钠 (NaMe2dtc) 和邻菲咯啉 (o-phen·H2O) 反应,制备了含Pr-S键的三元稀土有机配合物.化学分析和元素分析结果表明其组成为Pr(Me2dtc)3(phen).用TG-DTG法研究了它的热分解行为, 发现其热分解为一步完成,X射线粉末衍射证明直接生成Pr2S3.用"非模型等转化率法"研究了热分解过程的动力学,获得其表观活化能和指前因子数值范围、最可机理函数和模型函数.     

草酸铵试法鉴定Ca2+用NaNTU掩蔽Ag+和Hg2+

在实验的基础上,提出了用草酸铵试法鉴定钙时,用N-烯丙基-N′-(对苯磺酸钠)硫脲掩蔽Ag+和Hg2+离子干扰,与传统的H2S沉淀消除的干扰的方法相比,具有操作简便、条件易控制、无污染等优点.     

磁改性活性炭-非均相类Fenton体系去除水中四环素

环境中四环素(Tetracycline,TC)污染及去除是当前研究的热点问题，用粉末活性炭(Activated Carbon,AC)制备磁改性活性炭(Magnetic-modified Activated Carbon,MAC)，建立以去除TC为目标的磁改性活性炭-非均相类Fenton体系，四氧化三铁(Fe₃O₄)赋予了AC磁性，并可以作为非均相类Fenton反应的催化剂，该体系结合了活性炭法的吸附与非均相类Fenton法的降解，能够更高效地去除TC.通过SEM,EDS,FTIR和XPS对反应前后的MAC形貌、结构以及官能团进行分析，探讨该体系对TC的作用机理.同时考察了时间、MAC投加量、H₂O₂投加量、溶液的pH对MAC去除TC溶液的影响.结果表明，在TC浓度为50 mg·L^-1时，初始pH为3,MAC投加量为0.6 g·L^-1,H₂O₂投加量为5.0 mmol·L^-1，为该体系的最佳运...     

工业硫氰酸钠质量的研究 第一报:硫氰酸钠中甲酸钠对丙烯腈聚合影响的发现及其含量的测定

在以甲基烯丙基磺酸钠为第三单体,硫氰酸钠为溶剂的腈纶一步法工艺试验中,发现用不同批号的硫氰酸钠所得聚丙烯腈共聚物的粘度相差很大,经用红外光谱法、化学分析法等方法鉴定出硫氰酸钠中的主要杂质为甲酸钠。经过试验证明甲酸钠对硫氰酸钠浓水溶液中丙烯腈—丙烯酸甲酯—甲基烯丙基磺酸钠的共聚有严重的影响。因此建议硫氰酸钠中甲酸钠的含量可以作为腈纶生产中考核硫氰酸钠质量的一个重要指标,同时提出了硫氰酸钠中甲酸钠含量的测定方法。此法采用碱性介质中硝酸银沉淀法,除去 CNS-的干扰,然后用高锰酸钾—一碘量法测定滤液中的甲酸钠。操作较简便,数据重现性好,甲酸钠含量在0.5%以上,相对误差在1%以内。可供工业分析之用.     

基于双测量面阵列的波束成形方法研究

文章将双测量面阵列引入到波束成形(Beamforming)方法中,建立一种基于双测量面阵列的Beam-forming方法;该方法首先采用2个测量面获取声压,通过平面波近似和声压叠加原理,推导出一种简单有效的去除干扰声源影响的方法;随后以去除干扰后的声压代替测量声压作为输入,采用多重信号分类算法进行Beamforming重建,实现对目标声源的识别.数值仿真和实验研究表明,该方法可以有效地去除干扰声源的影响,准确地定位出目标声源位置.     

二苯硫腙还原法测定痕量 NO_2~-

NO_2~-在2MHCl 介质中能氧化二苯硫腙,使四氯化碳相中绿色减退。通过测定620nm 下反应前后四氯化碳中吸光度的改变,建立了测定痕量 NO_2~-的新方法。方法的灵敏度ε=3. 45×10~4升·摩尔~(-1) ·厘米~(-1) ,最低检出限为5. 0×10~(-8) gNO_2~-·ml~(-1) ,线性范围为0. 50-7. 5μg·NO_2~-·10ml~(-1) 。对干扰的金属离子 Cu~+、Cu~(+2) 、Hg~(2+)、Ag~+、Au~(3+)等,可在 pH3-7条件下,用二苯硫腙的四氯化碳溶液萃取除去。该法用于测定废水中 NO_2~-,结果是满意的。     

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