高血压症与微量元素

临床上将高血压分为原发性和继发性两类。原发性高血压称为高血压病。高血压症分为3型,即缓进型、急进型和老年性高血压。老年性高血压又称收缩性高血压,其特征是收缩压升高,舒张压变化很小,脉压增大,常合并冠心病。高血压症与微量元素锶、锌、铜有关。国内研究发现,人体内锶(Sr)含量愈低,则血压愈高。一期、二期、三期高血压患者的锶含量分别为5·26×10-3、2·77×10-3和1·65×10-3。国外学者观察46例妊娠高血压患者,其锌、铜、硒、铁、钙、镁及维生素E缺乏。但也有报道指出,高血压患者头发铜及血清铜升高。作者认为,出现这两种截然不同的结果是可以理解的。情况可能无变化,缺锌易患高血压,但早期缺锌者其血铜可能无变化,因锌与铜相拮抗,长期或严重缺锌会导致血铜升高。高血压患者应补充钾、锶、锌和硒。有遗传性钠过敏史者,高钠摄入、高钠潴留是导致高血压的危险因素。钠、钾相拮抗,因此补钾可减少体内钠的潴留。水果和蔬菜是富钾食物。服用药物碘化钾或碘酸钾应有医师指导。海带中锶含量相当高,是理想的补锶食品。核桃、花生、芝麻和瘦肉富锌。服用硒锌氨基酸口服液既可补锌又能补硒,对改善临床症状效果明显。此外,减少患者体内的铅、镉负荷有利于...     

金属氧化物脱硫/固硫反应动力学中的补偿效应

讨论了氧化锌中温脱硫、氧化钙高温固硫的补偿效应。实验发现,脱除硫化氢 和二氧化硫在反应过程中均先后在动力学控制区和粒子扩散控制区进行。改变非硫 气氛或添加催化组分,所得热重数据均可有效粒子模型处理。lnk_0-E_a及lnD_0- E_D呈线性关系。给出了补偿效应的理论解释。指出晶粒表面及内部缺陷等的随机 指数分布是出现该效应的主要原因。计算了两反应体系的等动力学温度。讨论了高 于和低于该温度时,反应活性与活化能不同的变化规律。并对粒子扩散化学反应性 质进行了探讨。     

庆祝游效曾院士80华诞暨教学研究60周年

<正>2013年是我国著名无机化学家、中国科学院院士游效曾先生80华诞。游效曾先生,1934年生。武汉大学学士,南京大学硕士。美国威士康星、伊利诺伊和佛罗里达大学访问学者。被聘为西班牙Alcala大学、香港大学、新加坡国立大学和台湾大学客座教授。1991年当选中国科学院院士。游效曾教授先后任南京大学配位化学研究所所长,国家重点实验室和化学化工学院学术     

缅怀我们的导师——张滂院士

2011年11月29日,我们敬爱的导师张滂院士与世长辞。噩耗传来,作为学生的我们悲痛万分。师恩难忘,谨以此文作为对先生的纪念,并表达我们对先生的感谢与怀念之情。张滂先生早年就读于西南联大,毕业后曾作为老一辈有机化学家吴学周先生的助手开展研究工作。1945年留学英国,先后就读于利兹大学和剑桥大学,1949年7月获得有机化学博士学位。据了解,张滂先生是第一位获得剑桥大学博士学位的中国人。张先生于新中国成立之际回国效力,投身于祖国的教育和科技事业,先后任教于燕京大学和北京大学。     

《广州化学》征稿细则

<正>一、投稿要求1.稿件内容须符合本刊的报导宗旨,论点鲜明,数据可靠,文字简练。来稿文责自负。2.接受网上投稿。投稿信箱:gzhx@gic.ac.cn3.来稿一经刊出,酌付稿酬,并赠送当期杂志。     

离子色谱-直接电导法测定碱土金属和过渡金属离子

本文报道离子色谱-直接电导法测定碱土金属和过渡金属离子。研究了流动相pH值、乙二胺浓度及柠檬酸和酒石酸浓度对金属离子分离的影响。结果表明,以乙二胺-柠檬酸为流动相可以同时分离碱土金属和过渡金属离子。用乙二胺-酒石酸作为流动相可以分离碱土金属离子。方法检出限为0.09~1.88 mg/L,加标回收率为97.6%~98.7%。该方法用于叶面肥试样的分析,结果良好。     

《化学通报》“纪念创刊80周年”专栏征稿和中国化学会《化学通报》戴安邦奖评审启事

.1934年,由中国化学会主办的《化学》——《化学通报》的前身正式创刊。这是我国化学界历史最为悠久的学术期刊。2014年,我们将迎来本刊创刊80周年大庆。本刊编委会和编辑部将举办系列纪念活动,并将全年开辟《纪念创刊80周年》专栏。为此,本刊特向全国化学同仁征求稿件。     

《应用化学》2020年征订启事

《应用化学》创刊于1983年,是经国家科委批准向国内、国外公开发行的学术性期刊。由中国科学院主管,中国科学院长春应用化学研究所和中国化学会主办,科学出版社出版。为中国科技核心期刊。《应用化学》设有综合评述、研究论文、研究简报栏目。出版周期短,报道新成果快。《应用化学》期刊被14家国内外重要检索机构、文摘收录。《应用化学》面向科研单位、大专院校和化学化工领域的科研技术人员。本刊承揽各类化学、化工材料、分析测试仪器及各类化学产品介绍和相关领域科技信息等广告业务。     

实验探究钢铁的腐蚀

在电化学的教学中,很多教师普遍认为钢铁在酸性环境下发生析氢腐蚀,在碱性或中性环境下发生吸氧腐蚀。。笔者对此进行了多次实验,发现此结论有误。这里和同行们一起探讨。     

探究教学论析

探究教学是现代西方料学教学理论和实践的重要基础之一。它以培养学生的探究素养和探究精神为主旨,强调科学方法、科学过程和科学观念的教育。突出学习中的学会探究和探究中学会学习。探究教学不仅有丰富的教育观,也有深厚的方法论。这就是探究教学的过程论。教学模式和教学策略。     

Cun、Agn和Aun(n≤9)团簇的静电极化率

The static polarizabilities and polarizability anisotropies of Cun,Agn and Aun (n≤9)clusters have been calculated by the B3LYP density functional method,which is a three parameter mixture of density functional and"exact" Hartree Fock exchange. The calculated results are compared with experimental polarizabilities of sodium clusters. It is shown that the size dependency of the static polarizabilities per atom of Cun,and Agn clusters possesses the same trend as that observed in sodium clusters exception of the Aunclusters while the polarizability of Au atom is much smaller than these of Cu and Ag.The(α-)of Au atom is the smallest and the(α-)per atom of Au approach to the values of Cu from the dimmer to the hexamer. It indicates that in Au clusters the electrons are more strongly attracted by the nuclei because of the more electrons. However,the absolute polarizabilities of the noble mental clusters are considerably smaller than those of the sodium clusters and the electronic structures of the noblemental are much more compact.     

Thermodynamics of dissolving and solvation processes for benzoic acid and the toluic acids in aqueous solution

Experimental data are presented for the solubility in water of benzoic and toluic acids from 5° to 65°C. From the solubility the molality of the monomeric form of the acid is calculated using literature data for both ionization and dimerization of the acid. These data for the monomer combined with data from the literature for vaporization of the solid and ionization in both the gas phase and the aqueous phase yield entropy and enthalpy changes for the solvation of molecular and anionic forms of the acid. A similar procedure is also applied to literature data for the solubility of benzene in water. It is shown that the hydration entropies of the monomeric forms are a linear function of their partial molar volumes. It is concluded that hydration of the undissociated o-toluic acid may be crucial to the increased acidity of that acid compared to benzoic acid.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

由合成气制备C_2含氧化合物用铑基催化剂中各组分间的相互作用

采用ＴＰＲ，ＥＰＲ，ＩＲ，ＸＰＳ等手段对由合成气制备Ｃ２含氧化合物的Ｒｈ基催化剂中各活性组分间的相互作用进行了研究．ＴＰＲ实验表明，Ｍｎ的存在除了促进金属铑在担体表面的分散，增加还原过程的耗氢量外，还使Ｒｈ物种的还原温度显著升高；少量Ｌｉ的加入导致氢向载体ＳｉＯ２的溢流，使体系的还原特性发生了明显的变化．原位ＥＰＲ和ＸＰＳ研究显示，添加剂与Ｒｈ相互作用，在催化剂表面形成了稳定的复合氧化物．助剂Ｍｎ主要起着吸引电子的作用，使还原后的催化剂表面上Ｒｈ＋物种的含量增加；相反，作为给电子助剂，Ｌｉ的加入稳定了表面Ｒｈ０物种．吸附ＣＯ的ＩＲ实验得到了与ＥＰＲ和ＸＰＳ实验相一致的结论     

The effect of coating on the stiffness and toughness of encapsulated fiber composites

The effect of the coating of the fiber on the stiffness and toughness of composite materials is presented in this paper. The type of composite material considered is of a macroscopically isotropic composite medium containing coated fibers. The models used to simulate such materials consists of: the cylindrical fiber, a cylindrical annulus of the coating, an annulus of the matrix enveloped by an infinite region of an equivalent composite consisting of a transversely isotropic material and representing the real composite with dispersed coated fibers. Solutions for the longitudinal, transverse and shear elastic moduli in the four-phase model were established assuming linear elastic conditions. The results were found to depend on the extent and the mechanical properties of the coating. The stiffness and toughness of the composite were evaluated in models representing plane-stress equatorial sections of the representative volume element of the real material according to the Hashin-Rosen model. The stiffness of the fiber composites was studied by varying the rigidity and the extent of the fiber-coating in the model and evaluating its influence on the overall mechanical behavior of the model. On the other hand, the toughness of the composite was evaluated by the method of caustics in models made of composite PMMA plates with PMMA inclusions coated with a ductile annulus. Interesting results were derived concerning the influence of the soft annulus on the mechanical behavior of the composite.     

Theoretical study of dielectric behavior of microcapsule suspensions with distributed drug release rate

Theoretical consideration is made concerning the dielectric behavior of aqueous suspensions of W/O-type microcapsules containing aqueous electrolyte solutions, especially concerning distribution effects of the electrolyte release rate on the dielectric behavior.It is shown at first that the distribution of the release rate causes electrical conductivity of the capsule interior. Next, it is deduced, in the light of a theory of the interfacial polarization, that the distribution characteristics of the capsule interior's electrical conductivity are closely related to those of the relaxation time for a dielectric relaxation exhibited by the suspensions. Several formulas are derived to describe the relation between the distribution characteristics of the release rate and those of the relaxation time.     

New aspects of migration and flame retardancy in polymer nanocomposites

Annealing of pristine polypropylene blended with the organomontmorillonite (OMMT) at temperatures of 180-340 °C under a stream of nitrogen and of nitrogen-air mixtures is investigated. The oxidative annealing brings about the dispersion of the OMMT in the polypropylene and the formation of a nanocomposite structure. This is evidenced by the increase in the interlayer distance ‘d’ as measured by small angle XRD, with time of annealing and with the weight percent of air. This indicates progressive intercalation of the polymeric matrix into the clay gallery and subsequently exfoliation. The degree of exfoliation is estimated by the extent of migration determined spectroscopically on the surface of the annealed sample. The accumulated clay on the surface due to migration hinders the penetration of the oxygen into the annealing melt as expressed by the decrease in the rate of migration with the increase in the air concentration. This indicates the increase in ageing and storage stability of nanocomposites with increase in the extent of migration. The extent of migration is proportional to the polar carbonyl groups formed on the matrix. The energy of activation of the migration was found to be 37.82 kJ/mol indicating that the rate-determining step of migration is diffusion controlled reaction. The penetration of oxygen into the melt is the first of five steps, followed by oxidation, intercalation, exfoliation and migration. Monitoring the migration with increase in the temperature enables the observation at 275 °C of the transition of the nanocomposite structure to noncolloidal microcomposite. Increasing the annealing temperature above 300 °C brings about a slow, low-temperature combustion and formation of a new kind of char on the surface of the sample.     

锌试剂与壳聚糖的结合反应机理的研究

为从分子水平认识多糖分子与小分子之间相互作用的机理,应用光谱法研究了壳聚糖(CTS)与锌试剂(ZCN)的相互作用机理;测得ZCN-CTS复合物吸收光谱出现新的吸收峰所需的临界ZCN/CTS摩尔比为2.67×103, CTS对ZCN的最大结合数为6.93×103,实验值与理论值相吻合,证明了多糖与生物探针相互作用理论模型的可靠性;探讨了ZCN与CTS相互作用产生变色反应的机理,认为其是在ZCN与CTS大分子间发生静电相互作用的基础上,主要由ZCN与CTS大分子间的疏水相互作用所引起.     

水稻秸秆与PVC塑料共气化过程中钾、钠、氯的迁移行为

采用固定床反应器,结合X射线衍射(XRD)表征和热力学计算研究了水稻秸秆与PVC塑料共气化过程中钾钠氯的迁移和状态变化。结果表明,混合物中氯的释放率与反应温度和PVC塑料的量(氯含量)有关。当反应温度为800~900℃时,PVC的量对混合物中氯元素释放率的影响最为显著;气化温度达900℃时,含PVC 20%(氯含量为11.5%)的水稻秸秆混合物中,氯元素的释放率较纯水稻上升了16.5%。与此同时,氯含量的增加也促进了钾钠在气相中的释放。气化温度为850℃时,当混合物中PVC比例大于20%(氯含量大于11.5%)时,氯对钾钠的气相析出有一定抑制作用;钾钠以KCl和NaCl的形式滞留在固相中,其含量随着混合物中PVC量的升高而降低。     

INFLUENCE OF THERMAL AND NON-THERMAL EFFECTS OF ULTRASOUND ON ISOTHERMS OF PHENOL ON NKA II RESIN*

1.INTRODUCTIONUltrasoundhasproventobeaveryusefultoolinenhancingthereactionratesinavarietyofreactingsystems.Ithassuccessfullyincreasedtheconversion,improvedtheyield,changedthereactionpathwayand/orinitiatedthereactioninbiological,chemicalandelectrochemicalsystem[1,2].Recentyears,thestudyofultrasonicsandsonochemistryhasexpandedconsiderably.Arapidlygrowingareaisthatof"environmentalsonochemistry",whichmainlydealswithdestructionoforganicsinaqueoussolution.Inaddition,theuseofultrasoundtoenhanced…