共查询到20条相似文献，搜索用时 62 毫秒
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“超滤”带来精纯世界杨小青“超滤”是一种以压力为驱动力，料液循环处理，溶剂和一定的溶质能够透过膜，而其余组分被截留的分离过程。超滤主要分离大分子物质，它的截留范围可以从０．０１ｕｍ的小分子到０．２ｕｍ的胶体粒子。超滤的分离机理是根据分子的大小和形态不... 相似文献
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采用超滤—树脂联用技术分离提取桑椹红色素,研究了微滤预处理、操作压差和膜面流速对超滤膜通量的影响,确定了超滤的最佳提取工艺为：操作压差0.12 MPa,膜面流速2 000 L/h.色素超滤液经HPD—100树脂吸附后用75%乙醇洗脱、蒸发、干燥可得到纯度较高的桑椹红色素产品,其色价为35.60,在超滤的基础上色价提高1.3倍,相对水提法提高了5.7倍. 相似文献
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介绍了以三氯化磷和甲醇为原料制备亚磷酸二甲酯（（CH3O）2POH）的工业化清洁生产工艺及实现零排放的关键技术．制备（CH3O）2POH安全稳定的清洁生产工艺条件：真空度不小于0．088MPa,反应温度不大于48℃,体积V（CH3OH）：V（PCl3）=1：0．7,CH30H和PCl3的流速分别为62L／min,43．5L／min,滴加时间为30min,反应时间80min．（CH3O）2POH经蒸馏,蒸馏终点温度145℃,蒸馏终点真空度不小于0．097MPa,获得含量99％、酸度0．13％的产品（CH3O）2POH．副产品氯化氢、氯甲烷和亚磷酸均得到回收利用,无排放． 相似文献
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EM和高分子絮凝剂对庆大霉素生产废水进行处理，结果显示单独使用EM时最佳的接种量是0．3％～0．4％，pH为8，处理时间为36小时，处理温度取自然温度(室温)，经正交实验最佳组合为B3A3C1，即最佳的温度为30℃，最佳接种量为0．5％，最佳pH为5。处理后COD从20000mg／L降至1000mg／L左右，经高分子絮凝剂处理最佳的pH为8.／10000的絮凝剂聚丙烯酸钠加量为0．75～1．0mL／250mL废液，沉降时间为1．5～2．0h，主要污染指标COD降低到了350mg／L，达到了国家排放标准(≤350mg／L)。 相似文献
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对观赏百合品种莫娜鳞片进行组培快繁条件的优化研究．结果表明,使用75％酒精消毒10s,0．1％升汞处理10min,最后用无菌水清洗5次灭菌效果最好,污染率最低;MS＋0．5mg／L6-BA＋1mg／LNAA为最佳诱导培养基． 相似文献
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崔绍波 《辽宁科技学院学报》2016,18(3)
通过正交试验,以硫酸镍和硫酸铜为主盐、次磷酸钠为还原剂研究了铝片表面的化学镀Ni－Cu－P工艺,其最优工艺配方为：硫酸镍25 g／L,硫酸铜2．0 g／L,次亚磷酸钠24 g／L,柠檬酸钠45 g／L,硫脲2．5mg／L,NaF 0．15 g／L,OP－100．8 mg／L,pH值9,温度70℃,施镀时间40min。通过耐硝酸变色试验检测了沉积层的抗蚀性,并讨论了沉积层抗蚀性的影响因素。 相似文献
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超滤膜分离技术提取茶多酚的研究 总被引：1，自引：0，他引：1
以福建安溪铁观音茶叶的茶梗为原料,联合采用超滤法和沉淀法,水浸提其中活性成分茶多酚的最佳浸提条件为:温度(80±3)℃,料液比1∶20,浸提时间40 min.使用10万分子量的超滤膜,在25℃的温度下,驱动压力0.15 MPa,料液比1∶80下进行超滤,使茶叶中的活性成分得到保留的情况下有效地澄清了茶汁,改善了茶饮料的感官品质.进一步探讨了金属离子沉淀法自超滤后茶汁中提取茶多酚的条件,结果表明,最佳沉淀提取条件:Zn2+为沉淀剂,Na2CO3溶液调节pH=6.00,茶多酚的沉淀率为91.7%,纯度97.1%. 相似文献
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采用732^#钙型树脂为层析剂，以不同pH的蒸馏水为洗脱液，用均匀设计法安排实验并考察在不同的实验条件下木糖和木糖酵的分离度及木糖酵的回收率，寻找较佳分离方法，确定较佳分离条件为洗脱液pH＝4．0．流速＝3．6m1／min，高径比H／D＝32，T＝50℃．在较佳条件下的分离度Rs＝0．29，木糖酵回收率为100％，色谱峰形较尖锐，峰宽窄，没有拖尾现象，可达到一定的纯化分离效果． 相似文献
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赵亚丽 《晋城职业技术学院学报》2012,5(4):91-94
液膜分离是一种高效低成本的金属离子预富集手段,本文采用组成为载体P-204（8％）,表面活性剂Span-80（3％）,膜稳定剂液体石蜡（0．5％）,膜溶剂煤油（88．5％）,内相HC1的浓度2．0mol／L的液膜萃取体系,考察了萃取时间、外水相酸度、转速、乳水比的分离条件对镉萃取率的影响。,实验优化后的萃取条件为萃取时间10min、外水相pH=4．50、乳水比1：4、搅拌速度200r／min;将液膜分离与火焰原子吸收相结合检测镉、铜离子,结果表明,此法灵敏度高、检测限低、检测范围宽。 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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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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陈美曦 《山东教育学院学报》2008,23(2):103-107
Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language. 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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Anton Franks 《English in Education》1999,33(2):39-49
This paper looks at the way drama works to bring a model of an arts curriculum into reality. He also shows how drama is valuable when discussed as a separate, autonomous subject in the school curriculum as opposed to one subsumed within English. He argues for a view of the arts and gives an example of a sequence of work in an English GCSE class based around Arthur Miller's play View from the Bridge. From this he draws out several strands about the relationship of the drama curriculum to the individual students and teachers, the school, and to culture. He also emphasises the primacy of performance in drama education. 相似文献