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...     

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。     

《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。     

《广州化学》征稿细则

[1]稿件内容须符合本刊的报道宗旨,论点鲜明,数据可靠,文字简练。[2]题目论文题目应准确、简明地表达文章的主题内容,字数不超过20字。不应有非规范的缩略词、符号、代号。文内标题序号用阿拉伯数字,以＂1、1.1、1.1.1＂三级标题表示。标题一般不超过15个字,不加标点符号。[3]署名作者署名一般不超过5人。首页脚注第...     

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。     

《应用化学》2013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,中国化学会和中国科学院长春应用化学研究所主办,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、研究快报栏目。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。     

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.     

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.     

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.     

TiO2膜光催化剂的改进及表征

提出用粉末-溶胶法制备TiO2薄膜型光催化剂,介绍了粉溶法的制备工艺及改变pH值对催化活性的影响.研究结果表明, 利用粉溶法或添加浓HNO3后制备的TiO2薄膜光催化剂表现出了较高的光催化活性.结合结构表征详细分析了其中的原因.认为粉溶法制备的催化剂表面更粗糙,比表面积增大,膜厚度减小,这些都可能是其催化活性提高的原因.而加酸后膜催化活性提高主要是因为酸性条件下表面几乎没有Ti3+表面态,利于光生电子与光生空穴的分离.     

A study of the ageing of the gel structure in a nonionic O/W cream by X-ray diffraction,differential scanning calorimetry and spin-lattice relaxation measurements

The time dependent changes of the lamellar gel structure in a nonionic O/W cream were studied. It appeared that the changes were connected with alterations in the hydrophilic layers of this lamellar gel structure. The structure of the hydrocarbon layers did not change. The alterations were induced by an increasing hydration of the surfactant molecules on cooling from the preparation temperature to room temperature. Ageing of the cream involves a decrease of the thickness of the hydrophilic layers and a change of the distribution of the surfactant molecules, resulting in, among other things, a decrease of the release rate of a hydrophilic drug. Ageing of the cream can be prevented by using the appropriate amount of starting materials or by the use of polymerizable surfactants. In the former case a cream, from which a drug is slowly released, is obtained. On the other hand, creams containing polymerized surfactants can release drugs at a relatively high rate.     

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.     

Thermophysical Properties of Granules of Instant Drinks in the Process of Structuring

In this article the research of the thermophysical properties of the material depending on its moisture content been represented. The interrelation of various physical properties with the content of moisture in the mass were detected. In addition, their dependence on the quantitative ratio and the properties of structural carcass and pore spaces were proved. The need to consider the volume phase composition of the mixture was justified. A formula to calculate the thermal conductivity coefficient of the product molded from disperse materials was obtained on the basis of Lykov criterion defining the property of drying material and volume phase concentrations. It is proved that the use of volume phase characteristics of disperse systems opens new possibilities for improving the methodologies for determining the those thermophysical properties of dry and wet dispersion materials, allows increasing the reliability results of these definitions, revealing the mechanism of anomalous heat conductivity of wet material.     

反相微乳液模板原位聚合制备纳米氯化银/聚甲基丙烯酸甲酯及其结构表征

用甲基丙烯酸甲酯(MMA)作油相,反相胶束微乳液作为模板,制备了纳米氯化银(AgCl)粒子,再进行原位聚合制备了纳米氯化银/聚甲基丙烯酸甲酯(AgCl/PMMA)复合材料.透射电镜(TEM)分析表明,纳米AgCl的尺寸为20～80 nm.扫描电镜(SEM)测试表明纳米AgCl粒子均匀地存在于PMMA基材中.红外分析证明,胶束中水和表面活性剂AOT的羰基在MMA聚合后微观环境发生变化,纳米粒子同聚合物之间有吸附行为.动态力学(DMTA)分析复合材料,发现纳米AgCl粒子与聚合物之间存在强烈相互作用,形成了中间相层(interphase layer),改变了聚合物的动态力学性能.     

Polymorphism and Conformational Equilibrium of Nitro-Acetophenone in Solid State and under Matrix Conditions

Conformational and polymorphic states in the nitro-derivative of o-hydroxy acetophenone have been studied by experimental and theoretical methods. The potential energy curves for the rotation of the nitro group and isomerization of the hydroxyl group have been calculated by density functional theory (DFT) to estimate the barriers of the conformational changes. Two polymorphic forms of the studied compound were obtained by the slow and fast evaporation of polar and non-polar solutions, respectively. Both of the polymorphs were investigated by Infrared-Red (IR) and Raman spectroscopy, Incoherent Inelastic Neutron Scattering (IINS), X-ray diffraction, nuclear quadrupole resonance spectroscopy (NQR), differential scanning calorimetry (DSC) and density functional theory (DFT) methods. In one of the polymorphs, the existence of a phase transition was shown. The position of the nitro group and its impact on the crystal cell of the studied compound were analyzed. The conformational equilibrium determined by the reorientation of the hydroxyl group was observed under argon matrix isolation. An analysis of vibrational spectra was achieved for the interpretation of conformational equilibrium. The infrared spectra were measured in a wide temperature range to reveal the spectral bands that were the most sensitive to the phase transition and conformational equilibrium. The results showed the interrelations between intramolecular processes and macroscopic phenomena in the studied compound.