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碳60的发现是荣获了1996年诺贝尔化学奖的重大贡献,将我们带进了又一个化学新世界。实践中碳60分了的独特构型引起了中学化学教师和学生的极大兴趣,但尚缺少其分了模型的简易制作方法。作者在教学过程中创造了一种碳60分了模型的制作方法。 相似文献
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乙酰乙酸乙酯-BR化学振荡反应的研究 总被引:2,自引:0,他引:2
本文首次报道了乙酰乙酸乙酯-IO-3-H2O2-Mn2+-H2SO4体系的化学振荡反应。研究了各种因素对振荡反应的影响,测定了最佳反应条件及振荡反应的浓度范围。研究了温度变化对振荡反应的影响,并计算了振荡反应的表观活化能,对振荡反应产物进行了分析,并测定了体系主要反应的计量关系,采用UV法对金属离子的作用和催化机理作了研究,探索了BR反应中I2的产生机理及消耗机理,对体系中有关反应物的作用作了说明。在FKN机理的基础上,对BR反应的自催化反应步骤和控制机理进行了初步的探索,并对有关实验现象作了说明。 相似文献
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自20世纪初期,德国化学家EmilFischer首先合成了甘氨酸二肽片段,并第一次提出“peptide”(多肽)这一名词,多肽化学的研究已经历了100多年的发展.1953年,Vigneand小组首次完成了生物活性肽催产素的合成,并因此于1955年获得了诺贝尔化学奖.1963年,Merrifield提出了多肽固相合成法,并发明了第一台多肽自动合成仪,大大简化了多肽合成的流程、提高了合成的效率,从而促使多肽化学实现了飞跃式发展,Merrifield也因此获得了1984年诺贝尔化学奖.1965年,我国科学家完成了牛结晶胰岛素的合成, 相似文献
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针对无机化学传统教学模式的不足,构建了无机化学微信平台。介绍了构建平台必需的微信公众号和微信群的建立过程和方法。分析了无机化学微信平台在教学中的实践效果,弥补了传统教学中的不足。讨论了无机化学微信平台的积极作用,提高了教师教学水平和学生的学习能力,达到了师生双赢的目的。 相似文献
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稀土抛光粉的生产及应用 总被引:22,自引:0,他引:22
综述了稀土抛光粉的各种制造工艺及其在玻璃抛光领域的应用现状,以稀土抛光粉不同的化学成分,粒度,用途等对稀土抛光粉进行了归纳分类,介绍了国内外稀土抛光粉生产企业的产生规律,产品特点,对国内外稀土抛光粉的制备工艺流程进行了归纳,阐述了稀土抛光粉的抛光工艺及抛光机理,重点讨论了稀土抛光粉的应用领域,预测了稀土抛光粉市场的未来,对稀土抛光粉的应用进行了展望。 相似文献
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采用多段升温法将壳聚糖改性,合成了取代度为1.84、平均分子量为3.08×105、等电点为7.28的N,O-羧甲基壳聚糖(CMC),分别用紫外光谱、红外光谱、荧光光谱对其结构进行了表征,并对其水溶液的Zeta电位、电导率、表面张力以及水分散体系中羧甲基壳聚糖微粒的粒径分布进行了研究.结果表明, N,O-羧甲基壳聚糖具有表面活性;介质的pH值和浓度对羧甲基壳聚糖溶液的稳定性有很大的影响. 相似文献
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为实现对卡塞格林光学系统中的非球面主镜表面面形的高精度检测,设计了一种二元位相型计算全息图(CGH)。介绍了工作原理,对CGH的相位模型参数的优化设计、衍射次级分离以及台阶位置与深度计算等关键问题进行了讨论。通过引入虚拟玻璃的概念快速建立非球面检测模型,针对卡塞格林系统主镜中心开孔的特点,通过加入同轴载波实现了衍射次级的完全分离,相比目前常用的倾斜载波方法简化了相位量化复杂度,数值仿真计算出了最优的台阶深度,降低了加工难度。给出了相应的设计方法及实例,研制投产了CGH。测试得到主镜面形的均方根误差为0.018λ,并与传统补偿器结果(RMS=0.019λ)进行对比,两者测试结果吻合,验证了该设计与检测方法的正确性,该设计方法简单快捷,适用于卡塞格林光学系统主镜面形检测。 相似文献
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Triacylglycerols can be synthesized from glycerol and fatty acids. During this equilibrium reaction water is produced, therefore a mixture of mono-, di- and triesters is obtained. One way to produce an excess of triacylglycerols is to remove the water produced during synthesis. This can be realized in an immobilized enzyme pervaporation system. The enzyme is immobilized onto the lumen side of a cellulose membrane where the organic phase is present. Air circulates at the shell side and the water activity is controlled with the use of a condenser. The lipase catalyzed esterification of decanoic acid and partial glycerides is studied in this reactor. The system is reaction limited. Only at low water activity conditions, an excess of triacylglycerols is obtained. The enzyme activity at the start of the experiments is independent of the water activity within the range studied. Stability is influenced: After 600 hours the activity is 26% of the activity at the start at aw = 0.1 and 71% at aw = 0.45. 相似文献
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流动注射分光光度法测定矿物浸提液中的游离氰化物 总被引:2,自引:0,他引:2
在氢氧化钠介质中游离的氰化物与苦味酸钠反应生成玫瑰红酸钠,并进行升温改善反应条件。双流路系统与单流路相比,峰形规范、光滑,能有效消除鬼峰,优化了显色条件,工作波长为510nm。按生产工艺要求的线性范围为4.0 ̄40.0mmol/L。进样频率为130次/h。已成功地用于矿物浸提液中游离氰化物的现场分析。 相似文献
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Susana de Marcos Rubén Hortigüela Javier Gatbán Juan R. Castillo Otto S. Wolfbeis 《Mikrochimica acta》1999,130(4):267-272
A new optical sensor for urea determination is presented. It is based on the enzymatic reaction with urease, which is first photoimmobilized with polyacrylamide onto a chemically polymerized polypyrrole (PPy) film. The main advantage of this sensor is that no indicator dye or pH indicator is needed, because PPy itself acts as the support and the indicator. These PPy films show an absorbance spectrum in the near IR range which is pH dependent. The variation of absorbance is thus directly related to the change of pH caused during the enzymatic reaction, which is also dependent on the urea concentration. The linear range of the sensor is from 0.06 to 1 M of urea, which is the common level of urea concentration found in blood and urine samples. 相似文献
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Peter G. Perkins Ashok K. Marwaha James J. P. Stewart 《Theoretical chemistry accounts》1980,57(1):1-23
An improved semi-empirical self-consistent scheme is described for calculating the band structures of three-dimensional solids. The basic level is that of CNDO theory. The non-orthogonality of the Bloch functions is recognised and allowance is made for all degrees of involvement of the overlap matrix. The calculation of the electron-repulsion integrals is formulated in a way suitable for solid-state problems. The method is tested on the standard systems; polyethylene, graphite, diamond, and hexagonal and cubic boron nitride. It is found that the valence band properties are satisfactorily reproduced. For optical spectra a configurational interaction scheme is required. 相似文献
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Experimentally determined volumetric properties of the liquid binary mixture of {water (1) + glycerol (2)} were processed to calculate the changes of the following thermodynamic parameters with pressure: excess molar Gibbs free energy, , excess molar entropy, , excess molar enthalpy, , as well as the enthalpy of mixing of water and glycerol, , at 100 MPa. The mixing enthalpies of water and glycerol, , became more exothermic with pressure increasing at all temperatures studied. 相似文献
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《印度化学会志》2021,98(11):100194
Pollution of environment is a major issue and has drawn attention of researchers throughout the globe. Water is polluted by various means like excretion of various industries and house releases, for example release of yarn, paper, and cloth industries etc. Present investigation consists of removal of such a pollutant. For this, synthesis of a novel quaternary nano particle sized photocatalyst ZrCdPbO4 is carried and its characterization by different analytical techniques is also carried out. This is further used for removal of colour pollutants from the environment and Erythrosine-B is considered as a role model. Effect of various operational parameters like pH, concentration of dye, amount of photocatalyst, irradiation power etc. is studied, maximum degradation condition is extracted, and it is observed that reaction follows pseudo first order kinetics. Scavenger study suggests the participation of OH free radical in the reaction. Complete degradation of the dye in presence of light and photocatalyst is reported here by. Reusability of the photocatalyst is tested and is found to work up to five cycles efficiently. 相似文献