共查询到20条相似文献，搜索用时 765 毫秒
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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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聚合硅酸氯化铝的制备、结构和性能研究 总被引：4，自引：0，他引：4
制备了聚合硅酸氯化铝絮凝剂(PASC)，其制备条件为常温，常压，反应时间3～4h。pH值3．0～3．5，产物Al2O3含量8．0％～10．0％，SiO2含量1．0％～2．0％。红外光谱证实聚铝离子与聚硅离子间存在着一种非离子性的键合作用，说明形成了聚合度更大的无机高分子聚合物。应用实验表明PASC较PAC的絮凝效果更好，稳定性更高。 相似文献
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维生素C对苹果多酚氧化酶活力的影响 总被引：4，自引：0，他引：4
本文探讨了抗坏血酸在不同温度、酸度和浓度条件下对苹果片中多酚氧化酶活力的抑制效果。结果表明，该酶活力在1．O％～1．5％的抗坏血酸溶液中显著降低，1．O％抗坏血酸在pH3或pH4的条件下，能显著降低酶的活力，在50～60℃范围内15min能显著降低酶褐变。 相似文献
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灿烂甲酚蓝标记分光光度法测定核酸 总被引：3，自引：0，他引：3
研究了灿烂甲酚蓝与小牛胸腺DNA相互作用，提出了测定ctDNA的新的光度分析法。室温、pH8．1tris-HCl的条件下，ctDNA的加入使灿烂甲酚蓝在其最大吸收波长636nm处的吸光度明显下降，下降的程度与ctDNA的含量呈线性关系，ctDNA质量浓度在0～3．0μg／ml范围内与△A呈线性关系，线性回归方程为△A=0．0032 0．0984C(μg/ml）(r=0．9987)，方法的检出限（3σ／k)为0．125μg/ml。该方法具有仪器简单，快速，选择性好等特点，对合成样品中ctDNA测定，RSD％=1．5～1．9，回收率在101％～104％，结果令人满意。 相似文献
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以乙腈-甲醇-0．05mol／L磷酸二氢钾溶液（10：20：70）（用磷酸调节pH值为4．0）为流动相．采用迪马钻石C18（250mm×4．6mm，5μm）色谱柱及紫外检测器，建立了甲钴胺注射液中甲钴胺含量的反相高效液相色谱检测方法．柱温：40℃：检测波长为264nm；流速：1．0mL／min．本方法测定的日内精密度为0．59％，日间精密度为0．67％，回收率为99．7％～100．5％，在160～240μg／mL范围内线性关系满足要求（r=-0．9999）；结果表明方法准确、操作简单、专属性强，可用于定量测定甲钴胺注射液含量． 相似文献
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高砷酸性废水除砷新工艺 总被引：3，自引：0，他引：3
刘琦 《洛阳工业高等专科学校学报》2005,15(1):10-11,27
对高含砷废水(砷含量为10000mg／L左右)采用分步、催化氧化后絮凝沉淀的处理方法。一步处理：采用石灰乳，调pH=3～4去除SO4^2-；二步处理：采用NaOH溶液使PH=9～10的范围，回收重金属；三步处理：加入催化剂-活性炭和Fe^2 通入空气氧化，使溶液中的As(Ⅲ)和Fe^2 氧化成As(V)和Fe^3 ，然后用石灰乳控制pH=6-9，使高价砷酸根与Fe^3 生成难溶的FeAsO4沉淀。经过上述处理后溶液中的砷小于0．5mg/L。 相似文献
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果树塑料大棚主要生态因子变化规律研究 总被引：1，自引：0，他引：1
塑料大棚内光照度(I)与外界光照度的变化趋势基本相似，但棚内低于棚外，透光率晴天在36．5％～49．6％之间，阴天在61．1％～69．2％之间，阴天高于晴天。棚内气温(ta)旬变化范围13．5～26．6℃，0cm地温(ts0)12．5～23．3℃，20cm地温(ts20)9．8～20．2℃，空气相对湿度(RH)55．4％～80．3％。晴天和阴天，I、ta、ts0先升后降，而RH先降后升，峰值和谷值均出现在14时。在不同环境因子的变化中．I起着主导作用，ta、ts0与I呈正相关，RH则与I、ta、ts0呈负相关。ts20在一天内较为平稳少变，与ts0相比受ta影响较小，且随时间的变化也较ta和ts0缓慢。 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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《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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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