分光乐度法测定饮料中的碘

本文利用碘-淀粉蓝色络合物在λ=580nm具有强吸收特性,用干灰化法处理饮料样品,以分光光度法测定饮料中微量碘,方法的特点是高灵敏度(ε=7.86×104L mol-1cm-1)、高精密度、线性范围适宜(0～2.0μg/m1)相关性好(相关系数r=0.9996)、方法简便易行等,可广泛应用于饮料中碘含量的测定.     

催化法测定微量硫的研究——利用硫催化碘氧化迭氮酸的反应

我们研究了硫离子催化碘氧化迭氮酸的反应(1),注意到由于有反应(2)的同时存在, 致使 I_2 2N_3~- S~→=2I~- 3N_2(很快)(1) I_2 S~=——2I~- S~0(较慢)(2)反应进行不长时间后,S~=全部被碘氧化,反应停止,但由于反应(1)的速度远超过反应(2),因此在这段反应期间内,微量硫离子的存在,仍将引起显著量的碘被迭氮酸还原,且发现碘的总消耗量与硫离子的初始浓度成直线关系。我们采用比色法和双铂电极电流测量法测定碘的浓度,拟定了高度灵敏的测定硫的方法。用该法测定硫的范围可从3××10~(-5)M到1.5×10~(-9)M,测定值的平均偏差不超过±10％,且操作从容简捷,结果的重现性较以往之动力学方法,也显著提高。 我们研究了溶液的pH、各试剂浓度、温度、零价硫及一些外来离子对反应中碘消耗量的影响;还利用所拟定的方法测定了金属镍及锰钢中负二价硫的含量,并用测定硫回收量的办法考核了方法的可靠性,结果都令人满意。     

电感耦合等离子体质谱法测定食盐及其代谢产物中碘的含量

采用电感耦合等离子体质谱法(ICP-MS)测定了加碘食盐及其代谢产物尿液中碘的含量.该方法在0.05~20μg/L范围内线性关系好,相关系数大于0.999 9、碘的检出限低、精密度好(RSD=1.2%,n=7).除标准加入法外,还通过国家标准物质的测定评价了该方法的准确性,测定结果均与国家标准值相吻合.对尿液的测定结果表明长春地区任选12名健康人并不存在碘缺乏的危险.     

流动注射化学发光法测定柠檬酸

在H2 SO4介质中 ,高锰酸钾可以直接氧化柠檬酸产生化学发光 ,由此我们建立了流动注射化学发光测定柠檬酸的新方法。该方法测定柠檬酸的线性范围为 1× 1 0 -5～ 1× 1 0 -3g/mL ,方法的检出限为 3× 1 0 -6g/mL ,相对标准偏差r=2 % ( 1 .0× 1 0 -4g/mL ,n =1 1 ) ,该法已用于饮料中柠檬酸的含量测定     

碘原位凝胶含量及体外释放度测定方法研究

为了建立碘原位凝胶的含量及体外释放度测定方法,采用自制装置进行体外释放度研究,释放介质为蒸馏水,转速为100r/min,温度为(37.0±0.5)℃。采用紫外可见分光光度法测定碘原位凝胶体外释放液中碘的含量,碘在CCl4溶液中的紫外检测波长为517nm。实验结果显示释放液中碘的质量浓度线性范围为40~200μg/ml(r=0.9997),平均回收率为99.4%,RSD=0.65%(n=9)。实验建立的含量及体外释放度测定方法操作简便、快速、准确度好,为相关制剂中碘的含量及释放度测定提供了一种新方法、新思路。     

溶液中微量碘的容量测定

一、引言溶液中微量碘的测定一般可用容量法,比色法和其它方法.在这些方法中,通常首先是用不同的氧化剂将碘氢化成碘酸根.再在溶液中加入过量的碘化钾,最后测定溶液中析出的碘.由于析出的碘为原来含量的六倍,故这一方法在微量碘的测定中,有其特殊的优点.反应如下:I~-+3Br_2+3H_2O=IO_3~-+6Br~-+6H~+ (1)IO_3~-+5I~-+6H~+=3I_2+3H_2O (2)常用的氧化剂有溴水和硷性高锰酸钾溶液,作者也曾对这二种氧化剂进行试验.发现当用硷性高锰酸钾作氧化剂时,需用酒精破坏过量的高锰酸钾,而微量的酒精又将为以后的滴定带来较大误差,故必须将溶液加热,除尽所有的酒精;此外高锰酸钾被酒     

碘对实验兔生产性能影响及其在肌肉、肝脏中蓄积规律研究

目的通过饲喂实验兔不同碘添加水平的饲粮,探讨碘对实验兔生产性能的影响及其在肌肉和肝脏中的蓄积规律。方法选用50日龄、健康塞北兔84只,按性别对等原则分成7组。第一组为对照组,其余六组为实验组。对照组饲喂基础饲粮,经检测含碘0.125 mg/kg,实验组在基础饲粮中分别添加0.2、0.4、0.6、0.8、1.0和1.4 mg/kg碘。测定20 d、40 d、60 d塞北兔的体重、体长和胸围。实验兔60 d后屠宰,测定皮张面积、胴体重、屠宰率及肌肉和肝脏中的碘含量,并统计饲料报酬和成活率。结果(1)饲粮中添加碘对塞北兔平均日增重、体长和皮张面积三个性状有显著的促进作用。(2)饲粮中碘添加量与肌肉和肝脏中碘的蓄积量呈显著的正相关关系(r=0.991;r=0.980)。结论实验结果与法国AEC肉兔饲养标准中碘水平1.0 mg/kg接近,为我国实验兔生产提供了较为科学的理论依据。     

2,5-二苯甲酰基-1,4-二碘苯的合成及其晶体结构

以2,5-二苯甲酰基-1,4-苯二胺为原料,分别经过2次无水体系中的重氮化、碘代反应,合成得到2,5-二苯甲酰基-1,4-二碘苯.通过熔点测定、元素分析、磁共振(NMR)及X线单晶衍射对产物进行了表征及晶体结构分析.分析结果表明该晶体属于正交晶系,Pbca空间群,a=10.980 (2)nm,b=15.866 (3)nm,c=21.110(4)nm,Dx=1.944g/cm3,Z =8,F(000)=2032,μ=3.43mm-1,最终偏差因子分别为R=0.0624,wR=0.1728.     

橙汁饮料中维生素C的测定

采用直接碘量法测定了三种橙汁饮料中抗坏血酸的含量.结果表明,橙汁饮料在碘量瓶中存放0.1 h至24 h,Vc含量最高,36 h后,VC含量明显下降.     

阻抑动力学分光光度法测定痕量碘-I--NO-2-KBrO3-AO体系

碘是人体必需的营养元素,是人体甲状腺素的重要原料,与人体的生长发育和新陈代谢密切相关,特别是对大脑的发育起着重要的作用,因此研究食物中微量碘的分析方法具有重要的现实意义.动力学光度法测定碘离子已有不少报道[1～3],大多为碘离子催化氧化还原反应体系,其中以碘离子催化Ce(Ⅳ)氧化As(Ⅲ)的反应体系研究最多.用碘离子的阻抑作用进行动力学分析测定碘的报道不多.本文研究发现,在磷酸介质中,痕量碘离子对亚硝酸根催化溴酸钾氧化碱性藏花红(AO)的褪色反应有显著的阻抑作用,据此建立了阻抑动力学光度分析测定痕量碘的新方法.方法简便快速,体系稳定,选择性和重现性好,用于食物中微量碘的测定,获得了满意的结果.     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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