共查询到20条相似文献，搜索用时 437 毫秒
1.
固相反应制备纳米氧化铜 总被引：7，自引：0，他引：7
以CuCl2·2H2O、Cu(NO3)2·3H2O与NaOH为反应物,在室温下通过固相化学反应合成CuO纳米粉体的两个反应体系,用透射电镜(TEM)和X射线衍射(XRD)对产物的组成、大小及形貌进行表征.结果表明:经室温固相化学反应所制得的CuO为单斜晶纳米CuO.另外,还从研磨方式、反应配比、反应体系、分散时间、及表面活性剂用量等方面对影响产物粒径大小及分散性的因素进行了探讨以下为所得结论的简要介绍:①反应速度是影响粒径大小的主要因素;②反应配比对产物的均匀程度及分散性有影响;③超声波分散可改变颗粒的分散程度;④表面活性剂的加入对改变颗粒的分散性有明显作用,其用量对粒径大小的影响存在最佳值. 相似文献
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本文采用水热法以CuSO4·5H2O和二乙醇胺为原料,成功制备了纳米晶构筑的球状CuO.结果表明了用水热法制得的由纳米晶构筑的球状CuO分散性好.此外,设置了对比实验,研究了原料起始浓度、反应温度、反应时间、pH值、添加剂的存在对制备纳米晶构筑的球状CuO的形态和大小影响,结果表明:原料浓度为7.17×103mol/L,并在130℃下,反应12h是制得纳米晶CuO的最佳实验条件. 相似文献
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吴芳芳 《渭南师范学院学报》2013,28(6):119-122
以氯化铜(CuCl2.2H2O)和尿素为原料,用水热法合成CuO微纳米结构材料,并对制备的微纳米CuO的结构及形貌进行了X射线衍射仪(XRD)、扫描电子显微镜(SEM)、红外光谱仪(IR)分析,对产物进行表征及分析,并探讨了纳米结构CuO的生长机制.结果表明:通过简单改变反应溶剂,成功实现了CuO微纳米形貌的调控.当反应溶剂为水体系时,产物尺寸为40 nm且比较均匀,得到的产物为单斜晶相的纳米CuO,具有工业化生产潜力. 相似文献
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研究前驱物浓度、超重力大小、反应时间、反应温度和反应介质体系的条件对Co3O4前驱物形貌的影响,发现制备花状Co3O4前驱物的最优条件是Co(NO3)2·6H2O和CO(NH2)2在1000/g超重力场、溴苯/水溶液体系、100℃条件下水热反应反应30min,通过前驱物的热分解制得Co3O4,采用SEM和XRD对样品的形貌和物相进行表征。将Co3O4粉末分别与乙炔黑、聚四氟乙烯(PTFE)按一定质量比混合压在镍网上,制成电极片,通过CV测试其电性能,结果发现超重力越大,制备的材料的交流阻抗值越小。 相似文献
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酶是具有高效催化能力的生物大分子物质,底物浓度相同时,酶的催化活性主要受温度、p H值等因素影响。温度一定时,酶活力最高时的p H值为该酶在该温度的最适p H。在不同p H值下,通过测定淀粉酶水解底物的程度,测定唾液淀粉酶的最适p H值。在不同p H条件下,淀粉被唾液淀粉酶水解,与碘液反应呈现颜色反应,通过对颜色的观察和分光光度计测量产物吸光值的大小,可知底物的反应程度,从而可以判断出唾液淀粉酶的最适p H。 相似文献
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张复兴 《衡阳师范学院学报》1998,19(6):4-7
以[C6H5CH2N（C2H5）3]Cl为相转移催化剂,用于羧酸钠和苄基氯之间的亲核取代反应合成了六种羧酸苄酯。研究了催化剂的用量、反应时间、反应温度、搅拌速度等因素对反应结果的影响,提出了合成羧酸苄酯的最佳反应条件。 相似文献
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通过解读2019年全国理综Ⅰ卷26题,深刻体验平衡及其移动思想在课堂教学中落地的重要性,讨论并设计CuO与不同铵盐溶液反应的系列实验,认为铵盐溶液溶解CuO主要是NH4^+而非H3O^+进攻CuO所致,Cu^2+与NH3形成配合物促进CuO被铵盐溶液溶解的化学平衡发生移动是主驱动力,从热力学和动力学层面揭示铵盐溶液溶解CuO的化学原理。 相似文献
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本研究分别采用了直接沉淀法和共沸蒸馏法制备出掺Fe^3＋量为0．1％的TiO2纳米粉体,用XRD分析方法对晶体的物相和粒径进行了表征。通过在日光源下催化降解水杨酸溶液,对其光催化活性的影响情况进行了比较。结果表明：以共沸蒸馏法制备出的掺Fe^3＋量为0．1％的TiO2纳米粉体在日光下的光催化活性较高。 相似文献
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本文作者在参考目前文献的基础上,通过考察不同的相转移催化剂、碱浓度、搅拌速度等条件,以价格低廉、易得的对二氯苯为原料,经硝化,常压水解合成邻硝基对氯苯酚,得到了较高的产率.并降低了对反应条件的要求,达到了工业化应用的要求. 相似文献
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邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献
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Rachel Zupek 《海外英语》2007,(11):40-41
我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了 相似文献
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YANGShiguo 《重庆大学学报(英文版)》2004,3(1):86-88
The problem on the geometrc inequalities involving an n-dimensional simplex and its inscribed simplex is studied. Aninequality is established, which reveals that the difference between the squared circumradius of the n-dimensional simplex andthe squared distance between its circumcenter and barycenter times the squared circumradius of its inscribed simplex is not lessthan the 2(n-1)th power of n times its squared inradius, and is equal to when the simplex is regular and its inscribed siplex is atangent point one. Deduction from this inequality reaches a generalization of n-dimensional Euler inequality indicating that thecircumradius of the simplex is not less than the n-fold inradius. Another inequality is derived to present the relationship betweenthe circumradius of the n-dimensional simplex and the circumradius and inradius of its pedal simplex. 相似文献
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Rajesh Kanoi 《海外英语》2007,(1):52
Today, Sunday morning, I sit thinking and typing at my computer. My thoughts are in my homeland, India and my body is in China. The body is here and mind there for a good reason. Mr. Hu is president and I am resident and both are in each other's countries (what a difference the absence of one small letter makes!). Mr. Hu will return in a few days and I will stay on longer. 相似文献