共查询到20条相似文献，搜索用时 62 毫秒
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黄颖芬 《黎明职业大学学报》2011,(1):36-40
阐述无机粉体表面改性的机理。无机粉体表面改性分为表面物理改性和表面化学改性两大类,分别总结物理涂覆、表面活性剂改性、高能表面改性、胶囊化改性等物理改性方法及表面沉积法、化学包覆、机械力化学、单体吸附包裹后聚合等化学改性方法的研究现状。对无机粉体表面改性方法进行展望。 相似文献
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采用空气等离子体对聚丙烯微孔膜进行表面改性,用X射线光电子能谱,扫描电镜表征膜表面形态和微观结构的变化。考察了改性膜的水接触角、水通量以及在浸没式膜-生物反应器中的动态抗污染性能力。结果表明,改性后聚丙烯微孔膜的水接触角从100°减小到40°,膜的水通量提高,污染率下降。改性后聚丙烯微孔膜的亲水性和抗污染能力得到较大提高。 相似文献
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为了提高亲水棉织物分离速度、分离效果及增加重复使用次数,采用简单的两步法对亲水棉织物进行表面改性,即先用没食子酸(Gallic acid)和硫酸铜(CuSO4)在棉织物表面形成GA-Cu(Ⅱ)络合物改性层,再用十八胺进一步修饰,制备疏水改性棉织物。利用全反射红外光谱对改性后棉织物进行表征,并通过测试改性后棉织物与去离子水的静态接触角来评价其疏水性能。结果表明：在本研究范围内的最佳实验条件为没食子酸浓度12.8 mg/mL、硫酸铜浓度10.0mg/mL、十八胺浓度8.0 mg/mL,室温下反应4.0 h,改性棉织物与去离子水的接触角为140.9°;改性后棉织物可用于植物油/水混合物和机油/水混合物的分离,分离速度快,效果好,可以多次重复使用。 相似文献
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以尿素为沉淀剂，用强迫水解方法对工业生产TiO2颗粒表面进行了Al2O3包膜表面改性．研究了氧化钛粉体分散性与pH值关系，包膜pH、温度及陈化时间等影响．采用FESEM、XRD和Zeta电位仪进行表征，结果表明：在碱性条件下可以在TiO2颗粒表面获得较理想的Al2O3包膜；工业生产TiO2颗粒进行Al2O3包膜表面改性，包膜层晶体结构以γ-Al2O3为主，分散性和稳定性提高． 相似文献
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Washburn动态渗透压力法测量粉体接触角 总被引：3，自引：1，他引：3
在Washburn动态法的基础上，组装了一套渗透压力法测量粉体接触角的实验装置。在以往的实验中，测定固体粉末的接触角时是利用液体在由固体粉末所形成的多孔塞中毛细管上升的高度与时间之间的关系来实现。本文利用液体在管内粉体床中上升时压力随时间的变化关系来测定粉体的相对接触角，主要测量了不同溶剂(水，甲醇、乙醇、甲苯和苯)在不同的温度下(20C、25C、30C和35C)对铝粉的相对接触角，得到了满意的结果。 相似文献
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以聚丙烯腈基活性炭纤维(PAN-ACF)为吸附剂,分别进行空气热氧化、硝酸浸渍、过氧化氢浸渍改性处理,对改性处理的PAN-ACF样品进行表征,包括SEM表面形态、比表面积BET、傅里叶变换红外线光谱(FTIR)表面基团以及总表面酸性基团;研究对痕量六价铬的吸附效果,分析PAN-ACF改性对吸附容量的影响。经过过氧化氢浸渍改性处理的ACF3炭微晶尺度变小,导致结构无序化,较大地提升了比表面积,但表面含氧官能团增势不明显;其对微污染水中六价铬的吸附效果最佳,吸附等温线相对于Langmuir方程,更符合Freundlich方程。 相似文献
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选用十六醇作为疏水改性剂对单分散球形纳米二氧化硅进行表面改性。考察改性剂用量、改性时间、改性温度等因素对改性效果的影响。并用FT-IR、DTA、SEM对改性前后样品进行表征。以DTA测试结果作为改性评价标准,通过正交试验优化改性条件。结果表明,在5.0 g二氧化硅、1 g对甲苯磺酸、100 m L辅助溶剂二甲苯中、改性剂十六醇用量4.5 m L、改性时间70 min、改性温度75℃条件下,改性效果最佳。 相似文献
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丁忱陈顺玉肖秀峰 《福建工程学院学报》2020,(1):12-17
采用氨解结合乳化及热致相分离的技术来制备改性聚乳酸微球,通过浸泡法让卵磷脂包裹在改性微球上,进一步提高改性微球的亲水性。探讨了卵磷脂溶液的浓度、浸泡时间对改性微球形貌和亲水性能的影响。实验结果表明,卵磷脂修饰改性微球的最佳制备工艺条件为:卵磷脂溶液的浓度为1%,浸泡时间为5h,在此条件下制备的微球卵磷脂包裹均匀且亲水性得到了改善。通过红外光谱,X射线光电子能谱表征微球,结果表明卵磷脂已经成功接枝到改性微球上,通过水接触角测试,卵磷脂修饰后的改性微球亲水性得到了进一步提高。 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 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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Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献
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Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F. 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