共查询到20条相似文献，搜索用时 62 毫秒
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该实验以BA、AA为核单体,并加入SiO2溶胶对其改性,以MMA、BA、AA为壳单体采用半连续核-壳乳液聚合法制备纳米SiO2溶胶改性纯丙乳液,着重探讨了引发剂用量对SiO2溶胶改性纯丙乳液的合成及性能的影响,并且进行凝胶率、吸水率、固含量等指标的检测.实验结果表明:在引发剂含量占单体的0.65%时,乳液性能最佳,其中凝胶率为10.77%,固含量为39.38%,吸水率为24.11%,离心稳定率为3.66%,各稳定性均合格. 相似文献
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吴玉萍缪诗盈周忠华黄悦 《福建工程学院学报》2021,(4):356-359
采用St?ber法合成碱性二氧化硅(SiO2)溶胶,利用溶胶-凝胶法制备酸性SiO2溶胶,共混两种溶胶,在玻璃基板上制备含“蛋挞状”结构SiO2复合薄膜。通过扫描电镜(SEM)、红外测试(FTIR)和接触角(CA)对复合膜进行结构表征。结果表明,含“蛋挞状”结构的SiO2 复合膜,不仅是一种粗糙层次结构,表现超疏水性,而且蛋挞中的220 nm SiO2“ 蛋黄”是相对平整区,能够减缓摩擦对结构的影响,具有较好的耐磨性。 相似文献
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采用溶胶-凝胶法和微波辐射法制备了Mg2SiO4:Mn2+,Dy3+红色发光材料.研究了以Mg2SiO4为基质,在单掺杂Mn2+的情况下,微波合成时间和Mn2+的掺杂浓度对发光性能的影响.选择最佳微波合成时间和Mn2+掺杂浓度,研究了共掺Dy3+浓度对材料发光性能的影响.通过这两种方法制备了在410nm激发下,发光中心... 相似文献
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采用溶胶凝胶法制备了Cu／SiO2催化荆,用浸渍法将Mg元素担载在Cu／SiO2催化荆制得Mg-Cu／SiO2催化荆,研究在NO＋CO反应中的催化活性．结果表明,Mg修饰的采用方法（c）制备的Cu／SiO2催化荆,当Cu的含量是载体SiO2质量的2％,Mg的含量是载体SiO2质量的3％时,Mg-Cu／SiO2催化荆活性最高,250℃时NO生成N2的转化率接近100％． 相似文献
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以硅酸钠为硅源原位生成SiO2增强橡胶 总被引：1，自引：0，他引：1
陈海燕 《泰州职业技术学院学报》2006,6(6):55-59
采用溶胶-凝胶技术，以硅酸钠为原料制得活性硅醇的THF溶液，再与天然橡胶及少量偶联剂混合，原位生成二氧化硅（SiO2）增强橡胶。论述了在酸性条件下制备特性聚硅酸的最佳反应条件，对温度，pH值及硅酸钠浓度的影响进行了研究。同时用热重分析（TG）测试材料的热性能，电子拉力机测量SiO2含量对材料的力学性能的影响。为弹性体杂化材料的制备提供了一种更具实用价值的新方法。 相似文献
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介绍一个新的适于材料化学专业开设的综合化学实验,拟采用溶胶一凝胶法制备SrAl2O4：Eu^2＋,Dy^3＋绿色长余辉荧光粉．整个实验包括了溶胶-凝胶法全部基本操作以及材料的结构测试（X-射线粉末衍射）、形貌测试（扫描电子显微镜）、光谱测试（激发和发射光谱）等．该实验不仅可以使学生对溶胶-凝胶软化学方法制备材料的过程及原理有所了解,而且能够学习材料基本表征方法,是一个涵盖内容全面,适于学生操作的典型实验． 相似文献
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以工业水玻璃为硅源,甲酰胺为催化剂,乙二醇为干燥控制化学添加剂,通过溶胶凝胶法和常压干燥技术,研究了酸的种类和浓度对块状SiO2气凝胶制备的影响.外观和显微结构观察以及性能表征结果表明,酸的种类对制备块状SiO2气凝胶有较大影响,采用醋酸进行催化时,可以得到完整不开裂的块状气凝胶;醋酸浓度为1.2 mol·L-1时,所制备的SiO2气凝胶密度为0.22 g·cm-3,孔隙率高速90％,收缩率为11％. 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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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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Wilfrid Bilodeau 《Interchange》1993,24(3):241-270
Résumé Cet essai évoque les contextes pédagogiques de l'écriture au-delà des formes d'écriture convenues en recherche, et questionne les usages scolaires de l'écriture. J'y suggère d'autres usages inspirés d'une approche qui inverse les rapports usuels entre communication et représentation, entre kinésis et mimésis. Cette approche vise une démystification du pouvoir de l'écriture à représenter le réel, à dominer la communication, et une promotion d'une écriture expressive et métaphorique, favorisant l'appropriation de cette technologie virtuellement libérante.Université Laval 相似文献
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GUO Bao-feng Xiao Da-wei 《重庆大学学报(英文版)》2005,4(3):129-133
Using virtual reality for interactive design gives a designer an intuitive vision of a design and allows the designer to achieve a viable, optimal solution in a timely manner. The article discusses the process of making the Virtual Reality System of the Humble Administrator＇s Garden. Translating building data to the Virtual Reality Modeling Language （VRML） is by far unsatisfactory. This creates a challenge for computer designers to do optimization to meet requirements. Five different approaches to optimize models have been presented in this paper. The other methods are to optimize VRML and to reduce the file size. This is done by keeping polygon counts to a minimum and by applying such techniques as object culling and level-ofdetail switching. 相似文献
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The awareness of individualism can be traced back to the period of American Revolution when the Declaration of Independence was produced.It expressed basic beliefs concerning freedom,equality,democracy,privacy and the relationship between people and government,which were exactly what the philosophy of individualism mostly dealt with at that time.This paper is to exploit the essence of individualism by analyzing the Declaration .The analysis enables us to reconsider its significance to the issue of America human rights and foreign policies. 相似文献
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Mother's Day--母亲节 Mother's Day falls on the second Sunday in May every year. This is the occasion we show appreciation to our mothers and to people who have worked so hard to take care of us. Today, I'm sharing thoughts from a friend about mother, love,and the study of English. When we were young students, a teacher touched our heart,and we all miss her very much on this special day in May. 相似文献
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李晓劲 《读与写:教育教学刊》2008,5(6)
Public speaking, as one kind of speech act, the speaker uses some pragmatic strategies, for example,the use of personal pronoun, in order to achieve effective communication. Speakers use the first personal pro-noun we and the second personal pronoun you conventionally, also there are some deviations in the use of person-al pronouns. However, theses kinds of uses have to be explained and understood in such a specific context. 相似文献
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宋少华 《读与写:教育教学刊》2008,5(5):3-5
This essay mainly studies the linguistic features of News English on stylistics.The study is made mainly on three aspects of News English.They are lexical features.sentence features and grammar features of News English.Through the study we find that News English,as a distinctive and new language.has its own lin-guistic features in words, sentences and grammar. 相似文献