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1.
任树林 《化学研究》2000,11(2):58-61
推导了络合返滴定曲线方程 ,绘制了络合返滴定曲线和计算了pN突跃。并利用双曲正弦函数的性质 ,提出了内含最大敏锐指数的络合返滴定误差计算公式 ,从而获得了计算络合返滴定pN突跃范围的公式。  相似文献   

2.
The problem of the stability of a confined atom when it is extracted from the confining cavity has been investigated, modeled by a spherical hard wall potential. The ionization probability when the atom is released from confinement has been obtained. The dependence of the ionization probability on the confinement radius and on the quantum numbers of the initial confined state has been studied. The probability density function of the ionization energy of the ejected electron has been obtained for the different cases considered. The oscillatory structure of this distribution function, with a principal maximum located in the neighborhood of the energy of the initial state and minima very close to zero has been elucidated. The sudden approximation has been applied and the analytic continuation method has been used to calculate the different stationary states.  相似文献   

3.
The effect of pH on the adsorption of anionic dye Titan yellow on the activated carbon from aqueous solution has been studied. It has been found that the Zeta potential of the activated carbon has a great effect on adsorption capacity of Titan yellow. The kinetic and the thermodynamic parameters of adsorption as a function of pH has been evaluated. The mechanism for adsorption of anionic dye Titan yellow on the activated carbon has also been discussed.  相似文献   

4.
由于外层镀有金属的塑料制品兼有塑料及金属材料的优点,因而是一类具有广泛用途的新型复合材料。其中以金属化的ABS塑料的应用最为广泛。**S塑料金属化的方法很多,其中以电镀法最受重视l‘]。为保证金属镀层与塑料表面具有良好结合力,使塑料表面形成四坑、微孔等均匀微观粗糙状态的粗化工艺是相当关键的步骤之一p‘。现国内外广泛采用铬一硫酸混合液的化学粗化法,但该法对环境污染较大。随着环保要求的日益高涨,其它粗化法越来越受到人们的重视[’]。本文探索了利用超声波的空化效应来粗化ABS塑料表面、为ABS塑料的电…  相似文献   

5.
本文用INDO系列方法对C~6~0^3^-进行了几何构型优化, 得到D~2~h构型, 表明C~6~0^3^-确实发生了Jahn-Teller变形, 导致单键变短, 双键变长, 其额外负电荷和单电子主要分布在赤道附近。以此构型为基础, 计算其电子吸收光谱, 与实验值基本吻合, 在对光谱进行理论指认的同时, 讨论了光谱红移的原因。  相似文献   

6.
Synergism in the extraction of scandium by a mixture of di-2-ethylhexyl phosphoric acid and a β-diketone has been studied. The nature of the extracted species has been investigated. The effect of temperature on extraction has been studied and synergism has been explained on the basis of thermodynamic parameters of the extraction process.  相似文献   

7.
张欣 《分子科学学报》2006,22(2):119-122
研究了一种纳米蜡乳液的制备方法。通过测试证明该体系稳定,得到平均粒径为57.6nm大小的纳米蜡乳液,可代替各种行业中使用的普通蜡乳液,如皮革[1]、纺织[2]、造纸[3][4]等行业·  相似文献   

8.
《Electroanalysis》2005,17(3):205-209
The reaction of benzoquinone with reduced thiol species has been investigated using potentiometric techniques. The specificity of this reaction for thiol functionality has been briefly assessed and the nature of the electrode response has been elucidated. The system has been characterized in terms of selectivity, sensitivity and the efficacy of using the system for the quantification of thiol containing pharmaceuticals has been demonstrated. The simplicity of the detection methodology is shown to markedly contrast alternative thiol detection strategies. The transfer of the technology to a mass production format through the adoption of screen print electrode formats has been achieved and the efficacy of the approach demonstrated. Recovery experiments using captopril and penicillamine in tissue culture as a model analyte system were performed.  相似文献   

9.
超临界流体干燥过程的分析   总被引:10,自引:0,他引:10  
以ZrOCl2•8H2O为原料,采用超临界流体干燥(SCFD)法,在短时间内制备出大孔体积高比表面ZrO2气凝胶超细粉.该法具有良好的稳定性和可靠性.建立了醇凝胶中液相含水量的分析方法,为产品质量控制及确认体系是否处于超临界状态提供了依据.对抽提后的溶剂分析表明,SCFD过程是一物理过程.对水的抽提干燥过程亦进行了初步的理论探讨.  相似文献   

10.
Three-dimensional shape of polyethylene single crystals grown from the melt has been studied. Two distinct types of lateral habit have been obtained: lenticular shape (type A) and truncated lozenge (type B) in the range of regime I and II. Electron microscopy has revealed chair-like shape of type B crystal and reconfirmed the planar shape of type A crystal. In the type B crystal, spiral growth has occurred frequently in the {110} sectors and the sense of the handedness of spiral terraces has been maintained. It has been, suggested that the frequens occurrence of spiral growth is responsible for a morphological change (axialite-spherulite) accompanying the regime I–II transition. The origin of the chair-like crystals has been discussed and, a possible mechanism has been suggested for the formation of spiral terraces; the mechanism is based on a distortion caused by the three-dimensional shape of chair-like crystals. It has been found that the chair-like crystals are curved in the opposite way to S-shaped lamellae observed by Bassett and Hodge in banded spherulites. In fact, the present work has led to the recognition of further classes of crystal with curving cross-sections and of distinctions between them. In final analysis, a unifying thread has been identified between lateral habits, growth kinetics and three-dimensional shape of lamellae, in turn, leading to some rationalization of multilayer developments including twisting in banded spherulites, the latter based on existing suggestions in the literature.  相似文献   

11.
用INDO系列方法对C60自由基负离子进行了几何构型优化,得到D2h对称性的构型,表明C60--确实发生了Jahn-Teller畸变,导致单键变短,双键变长,形成15种键,9种不等同碳原子,其额外负电荷主要分布在赤道附近。以此构型为基础,计算了C60--的电子光谱,与实验值吻合,在对光谱进行理论指认的同时讨论了光谱红移的原因。  相似文献   

12.
The brief review of industrial technologies of titanium-containing concentrates processing has been carried out. Drawbacks of the existing titanium manufacture schemes are shown and the necessity of the essentially new fluoride technologies development has been proved. The reactions proceeding during the fluorination of rutile concentrate with element fluoride are described in the given work. The thermodynamic research of the process has been carried using ASTRA software. Dependence of mass concentration change of titanium tetrafluoride has been investigated in products of reaction on the temperature of the process, and the choice of optimum excess of fluoride has been proved.  相似文献   

13.
Changes to the fundamental and analytical parameters of a plasma have been investigated when ethanol has been added to aqueous or organic solutions. Excitation temperature, electron number density, and intensity of the H(alpha) line increased when ethanol has been added to aqueous solutions, while an electron density decrease and signal reduction have been found when ethanol has been added to xylene. The sensitivity has been improved for all ethanol concentrations when water has been the solvent, but the reverse has been found for xylene solutions.  相似文献   

14.
对HDPE/CaCO3填充高分子材料SEM样品制作的镀材种类及镀金参数进行了选择,得出了适宜的镀金相关参数:喷镀时间为45min,喷镀电流为0.2-0.8mA,并将其应用于该材料的断口分析,其图像清晰,结果可靠.  相似文献   

15.
The evaluation of a macrocyclic glycopeptide antibiotic, eremomycin, as a chiral selector in capillary electrophoresis (CE) has been performed. The stability of eremomycin in solution and capillary electrolyte, as well as its optical and electrophoretic properties have been discussed. The effect of experimental parameters influencing the enantioseparation of several profens has been studied. Excellent enantioseparation of profens has been achieved and migration order has been validated. Comparison of enantioseparations of profens in CE by using eremomycin-mediated electrolytes and in HPLC with eremomycin immobilized on silica has revealed similar trends for both methods.  相似文献   

16.
An experimental study of the thermal decomposition of powdered cellulose and pine sawdust has been performed. The influence of the heating rate on the temperature profiles in the sample and on the solid conversion rate has been studied. A mathematical model without adjustable parameters has been used to calculate the temperature at different points in the solid bed and the average total solid conversion. The experimental results have been compared with those calculated by the model. A good agreement has been obtained for sawdust. Some differences are observed for cellulose at high heating rates, and the influence of the thermal conductivity and the reaction heat on the results has been analysed.  相似文献   

17.
茂金属 乙烯的流变性与加工性   总被引:8,自引:0,他引:8  
研究了丁烯-1共聚的茂金属聚乙烯(mPE)的流变性,发现茂金属聚乙烯的窄分子量分 布导致它在挤出加工剪切范围里熔体粘度高、对剪切敏感性差以及熔体从牛顿型转为非牛顿型所需的剪切速率、转变应力高,在挤出加工条件下流动性差,加工困难。对茂金属聚乙烯(mPE)进行改性制得MmPE,MmPE熔体对温度、剪切速率的敏感性提高,在加工温 度、加工剪切范围里的天观粘度降低,加工流动性得到了显著的改进,可在普通聚乙烯加工  相似文献   

18.
The specificity of the reaction of benzoquinone with reduced thiol species has been investigated and the nature of the amperometric electrode response elucidated. The analytical applicability of the methodology has been assessed and it has been shown that through appropriate selection of the redox properties of the indicating quinone, interference from other electroactive species can be minimised. A discrepancy in the reaction stoichiometry has however been found between the glutathione and cysteine quinone adducts and the implications in interpreting the resulting sensor response are rationalised. The adaptation of the approach to disposable, screen printed electrode assemblies has been investigated.  相似文献   

19.
茂金属聚乙烯的流变性与加工性   总被引:3,自引:0,他引:3  
研究了丁烯 1 共聚的茂金属聚乙烯(mPE) 的流变性,发现茂金属聚乙烯的窄分子量分布导致它在挤出加工剪切速率范围里熔体粘度高、对剪切敏感性差以及熔体从牛顿型转为非牛顿型所需的剪切速率、转变应力高,在挤出加工条件下流动性差,加工困难.对茂金属聚乙烯(mPE) 进行改性制得MmPE,MmPE 熔体对温度、剪切速率的敏感性提高,在加工温度、加工剪切速率范围里的表观粘度降低,加工流动性得到了显著的改进,可在普通聚乙烯加工设备上,制备性能优良的茂金属聚乙烯薄膜制品.  相似文献   

20.
聚苯胺/膨润土纳米复合材料的合成与表征   总被引:9,自引:0,他引:9  
通过嵌入手段设计与合成同时具有某些无机和有机物双重性能的新型材料-无机/有机纳米复合材料,是科学家们关注的课题[1].Inoue等人[2]采用蒙脱土吸附苯胺单体然后电氧化的方法制备了聚苯胺/蒙脱土(Pan/Mont)复合材料,由于Mont片体的表面吸附了苯胺,所合成的为聚合物包覆的复合材料,这样在一定的程度上影响了材料的各向异性.本文采用离子交换,洗涤除去吸附在粘土颗粒表面的单体,成功地合成了非包覆的聚苯胺/膨润土壤(Ben)层状纳米复合材料,并用FTIR等方法对材料进行了表征.该材料兼有粘土的离子交换性能和聚苯胺的良好…  相似文献   

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