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1.
王勇 《化学教育》1991,12(5):33-33
一、反应原理在放电条件下,N2和O2能直接化合生成无色的一氧化氮。放电N2+O2(?)2NO一氧化氮在常温下很容易和O2化合,生成棕色并有刺激性气味的NO2。二、仪器及药品打气球、贮气瓶2个(一个标出刻度)、两口玻璃球(容积140ml)、铁架台、铁丝电。  相似文献   

2.
今年2月8日是俄罗斯天才的化学家门捷列夫(1834—1907)诞生125周年纪念。特选此译文刊出以为纪念。  相似文献   

3.
苏联共产党第十九次代表大会的决议指示出化学教师应该提高关于综合技术教育的教学质量,更密切地联系学习与生活,使学生认识重要化学生产的科学原理。氨的制造是属于重要化学生产之列的。研究氨的制造是具有重要的教育教养意义。这课题的材料,可以提供作复习和更深入地去认识以前所熟悉的物质的性质和扩大瞭解关于反应进行的条件,以及在工业上的管理方法.在八年级末学期已经学过硫酸的制造,从而熟悉了一些化学工业制造原理,如阶段的划分和流水作业的装置,扩大反应物质的表面,逆流原理,温度和压力的影响,热的交换等等,在研究氨的制造中巩固了这些原理,并且增加了关于适当的压力和循环作业的利用等概念。  相似文献   

4.
前言有机试剂是用于化学元素和化合物的测定、分离与浓集、掩蔽的有机化合物。这类化合物数量很多,在分析化学中得到极其广泛的应用。有机试剂结构及其与反应性能之间关系的研究是有机试剂理论研究的基本问题。早在本世纪二十年代Feigl就提出了分析功能团的概念。这个概念广泛地应用于有机试剂的研究中,并不断得到丰富和发展。这一概念的出现,为人们研究有机试剂结构与反应性能的关系奠定了基础。随着现代科学技术的不断发展,X射线衍射、红外光谱、拉曼光谱等现代技术也相继用于有机试剂的研究,使人们对有机试剂的认识进一步加深。此外近代迅速发展起来的络合物结构理论、量子化学方法以及计算技术也被用于有机试剂的研究中,从而使得从理论上  相似文献   

5.
以直线交叉法为依据,根据最小二乘原理,采用Matlab GUI工具设计了一款用于计算二元共聚合反应竞聚率的图形用户程序。与传统的求解竞聚率方法相比,该图形用户程序具有设计原理简单、计算快捷的特点;同时程序提供界面简洁、交互友好的数据输入平台,实用性强。实际应用表明:采用该款图形用户程序所测得的数据与微机动态搜索法、Tidwell-Mortimer法相近,而比采用斜率截距法计算竞聚率的最小差方和更小,并且也避免了采用斜率截距法由于所用方程的非对称性造成的计算结果的不一致性。  相似文献   

6.
对公认的Clapeyron方程的推导的不同意见   总被引:1,自引:1,他引:1  
对公认的Clapeyron方程的推导的不同意见郭余年,赵凤云(吉林工学院轻化工程系长春130012)Clapeyron方程问世干热力学第二定律成立之前。第二定律建立以后,赋予了它以新的内容,使其成为描述单元系任意温度(压力)、任意两相平衡的普遍公式。...  相似文献   

7.
相虎 《化学教育》2003,24(4):45-45
该文对现行的高中化学 (试验修订本 )第二册中关于乙酸乙酯水解实验的不足之处进行了分析,并提出了改进的方法,对其实验内容和实验效果进行了讨论。  相似文献   

8.
砷的光度分析法的进展   总被引:8,自引:0,他引:8  
文中着重介绍了近年来砷的光度测定方法的新进展,包括砷斑法、Ag(DDC)光度法、分单质银分散体系光度法、砷钼蓝光度法等。引用文献85篇。  相似文献   

9.
自从本刊1975年第二期“金的快速测定”一文发表以后,读者来信提出了宝贵的意见,认为此法测定金时铊有干扰,且试样分解方法可能使金的结果偏低。过去,我们分析的样品中不含有铊,故对铊的干扰未作考虑。现经试验,在溴氢酸存在下,三价金在低温蒸干时,随时间、温度、溴氢酸用量的不同,均有部份金被还原造成结果偏低。铊的存在对金的测定有干扰。因此对金的快速测定作如下的补充。  相似文献   

10.
将含不同负离子的苄基紫精分散在混合有PVP的MMA-HEMA共聚物基质中可制成耐水的光致变色膜。它们的光致变色速度的大小随紫精负离子的不同而有如下序列:V6(PF6^-)〉V5(BF4^-) ̄V4(ClO4^-)〉V3(CH3-苯环-SO3^-)〉V2(Br^-) ̄V1(Cl^-)。这与这些紫精在DMF中的溶解度以及在共聚物基质中的溶解性大小的序列相一致。负离子对这些光致变色膜在空气中的氧化退色速  相似文献   

11.
三氧化铬超微粒的制备与表征   总被引:8,自引:0,他引:8  
我们曾首次报道了Fe_2O_3超微粒溶胶具有大的三阶光学非线性响应,其X~((3))值与商品用的掺杂CdS_(1-x)Se玻璃相近,并对其产生机制进行了初步研究.本文用微乳液法制备了经十二烷基苯磺酸钠(DBS)和硬脂酸(ST)表面修饰的Cr_2O_3超微粒,并用TEM、IR、XPS及紫外可见吸收光谱进行了表征.  相似文献   

12.
采用热陈化微乳液及浸渍-提拉技术,制备了具有自清洁功能的TiO2薄膜。 考察了微乳液中表面活性剂十二烷基苯磺酸(DBS)的用量对TiO2薄膜的表面形态和微观结构的影响。 进而对合成的TiO2薄膜的光催化活性、光致亲水性能及实际环境中的自清洁效果进行了测试评价。 随着表面活性剂DBS用量的增加,微乳液中的分散质点尺寸减小,但热陈化后所获得的TiO2粒子表现出凝集现象。 在DBS用量为0及58 mg/L时,所获得薄膜表面较为平整,由15~20 nm大小的TiO2粒子组成。 这些薄膜在无紫外光照射时,水接触角增大的速度较慢,并且在紫外光照射下能迅速恢复其超亲水性能。 将薄膜置于室外25 d后其表面无灰尘粘结,水接触角由原来的0°增大至14°~18°。 当DBS用量为580 mg/L以上时,薄膜表面起伏不平,粗糙度过大,对应TiO2薄膜光致亲水性能较差,室外放置25 d后,水接触角由原来的0°增大至46°~48°。  相似文献   

13.
The non-isothermal crystallization kinetics of isotactic polypropylene (iPP) and nucleated iPP was investigated by DSC. The crystalline morphology of iPP was observed by polarized light microscopy. It was found that the crystallization rate increased with the addition of nanometer-scale calcium carbonate (nm-CaCO3) particles. The addition of dibenzylidene sorbitol (DBS) could greatly reduce the spherulite size of iPP. The crystallization temperature for the iPP with DBS was higher than for non-nucleated iPP. DBS was an effective nucleating agent for iPP. The results of measurements suggested that there was a coordinated action to the crystallization of iPP when the organic nucleating agents (DBS) and nm-CaCO3 were added to iPP together. Comparison to the modified Avrami equation and Ozawa equation, another method—Mo’s method can describe the non-isothermal crystallization behavior of iPP and nucleated iPP more satisfactorily.  相似文献   

14.
1前言早在70年代末80年代初,就有文献报道在载体上的金属Pd的某些性能,并注意到将其作为催化剂在甲醇合成上有很高的活性和选择性[1~3],然而并没有继续进行系统研究.80年代末,Sachtler等人开始在这一领域进行更广泛、更细致、更深入的研究[4~8].他们不仅研究了载在分子筛上的Pd,也研究了Pd与其他过渡金属所形成的合金的性能.它们的催化性质研究包括对CO加氢、新戊烷和氢解和异构化以及甲基环戊烷的开环和扩环反应[4~9].对Pd的其他性质的研究,还包括采用TPR、TPD、TPO和TPMS等技术,分析了Pd或其合金等金属原子在NaY分子…  相似文献   

15.
Relation between structure and properties is studied for polypropylene (PP) containing 1,3:2,4‐di‐benzylidene sorbitol (DBS) that forms network structure composed of nanofibrils in a molten PP. It is found that the aggregation state of DBS, which can be controlled by the applied flow field and thermal history, affects the spherulite texture of PP and thus the transparency. When injection‐molded products, in which the nanofibrils of DBS orient to the flow direction, are reprocessed at 180 °C, that is, lower temperature than the melting point of DBS, the obtained material shows high level of transparency, although it has been believed that sorbitol‐derivatives have to be melted and dissolved into the molten PP at high temperature, for example, 240 °C. Further, it is found that the particle flow occurs in the blend at 180 °C. The applied shear force generates the particles, that is, flow units, by the fragmentation of the network structure. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 41–47, 2008  相似文献   

16.
Monodisperse ruthenium nanoparticles were prepared by reduction of RuCl3 in 1,2-propanediol. The mean particle size was controlled by appropriate choice of the reduction temperature and the acetate ion concentration. Colloidal solutions in toluene were obtained by coating the metal particles with dodecanethiol. High-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XANES and EXAFS for the Ru K-absorption edge) were performed on particles of two different diameters, 2 and 4 nm, and in different environments, polyol/acetate or thiol. For particles stored in polyol/acetate XPS studies revealed superficial oxidation limited to one monolayer and a surface coating containing mostly acetate ions. Analysis of the EXAFS spectra showed both oxygen and ruthenium atoms around the ruthenium atoms with a Ru-Ru coordination number N smaller than the bulk value, as expected for fine particles. In the case of 2 nm acetate-capped particles N is consistent with particles made up of a metallic core and an oxidized monolayer. For 2 nm thiol-coated particles, a Ru-S bond was evidenced by XPS and XAS. For the 4 nm particles XANES and XPS studies showed that most of the ruthenium atoms are in the zerovalent state. Nevertheless, in both cases, when capped with thiol, the Ru-Ru coordination number inferred from EXAFS is much smaller than for particles of the same size stored in polyol. This is attributed to a structural disorganization of the particles by thiol chemisorption. HRTEM studies confirm the marked dependence of the structural properties of the ruthenium particles on their chemical environment; they show the acetate-coated particles to be single crystals, whereas the thiol-coated particles appear to be polycrystalline.  相似文献   

17.
The amphiphilic poly(methyl methacrylate-block-2-(dimethylamino)ethyl methacrylate) (PMMA-b-PDMAEMA) block copolymer brushes on the surface of clay layers were synthesized by in situ atom transfer radical polymerization. X-ray diffraction results indicate that both exfoliated and intercalated structure can be found in the nanocomposites. The block copolymer brushes can make different nanopatterns on the surface of clay layers after treatment in different solvents. After treatment in tetrahydrofuran block copolymer brushes form lamella structure on the surface, and after treatment in water surface micelles and wormlike structure can be observed. PMMA colloid particles armored by clay nanocomposites were prepared by suspension polymerization. Transmission electron microscopy and scanning electron microscopy were used to characterize the structure and morphology of the colloid particles. Colloid particles with clay layers around the surface can be observed. X-ray photoelectron spectroscopy (XPS) was used to analyze the surface of the colloid particles. N1s binding energy of PDMAEMA blocks on the surface of clay layers was detected by XPS. The two peaks of the N1s binding energy indicate two different nitrogen environments on the surface of clay layers. The peak with a lower binding energy is characteristic of neutral nitrogen on PDMAEMA blocks, and the peak with a higher binding energy is attributed to protonated nitrogen on PDMAEMA blocks.  相似文献   

18.
The surface purity of silicon wafers is an important parameter to monitor for yield improvement of semiconductor devices in a production line. Surfactants are used to reduce the surface potential in order to facilitate the removal or cleaning of particles and metals. Traces of surfactant residues from the cleaning bath may still be present on the wafer surface after the final cleaning step. In this report, two capillary electrophoresis (CE) methods for the analysis of dodecylbenzene sulfonate (DBS) are developed for monitoring the surfactant residues in the wafer manufacturing process. One method is developed for the sensitive determination of all DBS homologues and isomers in one single peak. Another method is developed for the fingerprint analysis of the homologues and isomers of DBS. The Taguchi methodology was used as a systematic optimization tool for the DBS analysis by CE. The experiments were evaluated by calculating the signal-to-noise ratio values with four responses. The lowest detection limit for DBS was 15 microg/L at 95% confidence level. The percent recovery of surfactant was between 90% and 110%.  相似文献   

19.
水热法制备表面修饰的钛酸锶纳米微粉   总被引:2,自引:0,他引:2  
以工业原料和常用试剂TiCl4、Sr(NO3)2和KOH为基础原料,通过添加表面活性剂十二烷基苯磺酸(DBS),采用水热法制备出表面包裹有DBS的钛酸锶纳米微粉,并应用红外光谱,X射线衍射谱,透射电子显微镜,热分析等一系列手段对其微结构进行了表征.结果表明:样品为表面包裹有DBS的钛酸锶纳米微粉,其形状较为规则,粒度分布较窄,单分散性较好.粒子的平均粒径为120nm,包裹膜的平均厚度为6nm左右.根据X光谱测量,表面修饰后的钛酸锶纳米微粉均以立方相存在.一般体相钛酸锶微粉为极性粉体.而表面修饰后的钛酸锶纳米微粉能够较为稳定地悬浮于非极性液体如正己烷中,说明SrTiO3粉体的极性表面被DBS包裹后,变为非极性.  相似文献   

20.
The application of X-ray photoelectron spectroscopy (XPS) for studies of surface layers of objects with spherical shape was investigated using as examples polystyrene and poly(styrene–acrolein) microspheres with attached human serum albumin (HSA). The amounts of immobilized protein were determined by the standard biochemical Lowry method and by XPS, using the intensity of the N1s signals of HSA as a basis for evaluation. The XPS data were treated by taking into account the spherical shape of the particles analyzed (variable take-off angle of ejected electrons). The best agreement between the results of the biochemical and XPS determinations was found assuming that for the average particle the takeoff angle varies from 0° to 72.7°. This reflects the fact that in the multilayer arrangement of particles, placed onto the support of the XPS apparatus, the particles from the upper layer partially screen the edges of the particles in the layer below. Received: 23 November 1999 Accepted: 16 March 2000  相似文献   

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