KF／Al2O3催化合成苄叉丙酮

以苯甲醛和丙酮为原料，氟化钾／氧化铝作催化剂合成了苄叉丙酮，通过正交实验得到了影响反应的四种主要因素的大小顺序为：原料配比＞催化剂用量＞反应温度＞苯甲醛的滴加速度；最佳工艺条件：丙酮：苯甲醛：催化剂物质量的比为1:0.6:0.05，反应温度40℃，苯甲醛滴加速度2h，反应时间1h，收率可达95.0%，产品用于镀锌光亮剂合格。     

MAP法去除毛皮加工废水中氨氮的实验研究

采用化学沉淀法有效去除毛皮加工废水中高浓度氨氮,探讨了沉淀剂种类、废水pH值、药剂物质的量配比及反应时间等因素对氨氮去除效果的影响.结果表明,在原废水氨氮平均浓度为130 mg/L,pH=10,n(Mg)∶n(P)∶n(N)=1.3∶1.1∶1,反应时间为20 min的条件下,废水中氨氮去除率达到94%以上,为后续生化处理出水COD和氨氮达标排放创造了有利条件.     

共沉淀法制备纳米Fe_3O_4磁性粒子的工艺研究

用两种不同沉淀剂制备了纳米Fe3O4磁性粒子,对二种工艺的主要反应条件进行了比较研究,都制备出了粒子尺寸为8~12 nm,正态分布比较好的粒子。一、25%NH3.H2O(A.R.)作为沉淀剂和pH值的调节剂,pH≥9,Fe3+/Fe2+的物质的量之比的值约为1.75,反应时间为1h,温度控制在40℃。搅拌速度为1 500 r/min;二、3mol/L氢氧化钠溶液作为沉淀剂,碱过量25%,Fe3+/Fe2+的物质的量之比约为2∶1.2,反应时间为1 h,反应开始时温度为70℃,反应10 min后将温度降至50℃,再反应50 min。搅拌速度为1 500 r/min。产品的铁含量接近理论值,干粉的磁化率也较理想。     

对溴苯异氰酸酯的合成研究

研究以对溴苯胺和三光气为原料合成对溴苯异氰酸酯,重点讨论溶剂、反应温度、反应时间和原料配比等对合成工艺的影响。研究表明：以乙酸乙酯为溶剂,滴液温度-5～0℃,回流温度78℃,反应时间为5.0 h,三光气∶对溴苯胺=1∶2（摩尔比）,对溴苯异氰酸酯的收率可达90.4%。     

核/双壳医用磁性微球的研制

用共沉淀法制备Fe3O4磁性粒子,选用聚乙二醇和琼脂制备核/双壳医用磁性微球.最佳工艺条件为:Fe3+/Fe2+之比在1.70～1.75;沉淀剂25%NH3.H2O过量20～30%,在温度35℃,pH值11,反应时间为1h;琼脂的包覆最佳温度为50℃,pH值为9,时间1h;聚乙二醇包裹最佳温度为55℃,pH值为4,时间1h,可以通过调节搅拌速度和超声波分散时间控制Fe3O4粒子的尺度,实验确定包覆剂用量.并用透射电镜、分光光度计、古埃磁天平等进行了初步表征.     

水热法制备氧化锆超细粉体工艺研究

文章以价格低廉氧氯化锆、氢氧化钠等无机盐为原料,利用水热法制备生物陶瓷用超细氧化锆粉体,通过对pH值、反应时间、反应的温度、矿化剂的用量等因素进行实验研究。结果表明：适宜的工艺条件为水热反应温度180℃、反应时间5 h、控制溶液的pH＝10、适宜的矿化剂浓度为0．1mol／L。     

十二烯基丁二酸淀粉酯合成的研究

以玉米淀粉和十二烯基丁二酸酐为原料制备酯化淀粉,讨论了反应体系的pH值、反应温度、淀粉乳的浓度以及反应时间对产物取代度的影响,并得出最佳工艺条件：30％淀粉乳,反应时间为7h,反应温度为35％,pH值为9-10,制得产品的取代度为0．01380。     

化学沉淀法处理焦化废水氨氮研究

研究了焦化废水中氨氮的来源和组成，提出用化学沉淀沉淀剂脱除焦化废水中氨氮的方法。着重探讨了不同操作条件，如溶液pH值、Mg^2＋：NH4^＋：PO4^3-、温度、反应时间及沉淀时间对氨氮去除率的影响，表明在pH为8～10、水温为25℃-30℃、反应时间为20min、沉淀时间为15min、Mg^2＋：NH4^＋：PO4^3-为1：1：1时对焦化废水中的氨氮有较好的去除效果。     

碱渣制六水合磷酸铵镁反应的影响因素研究

用碱厂废渣添加工业磷酸、氨水进行反应来制缓释性肥料-六水磷酸铵镁,对该反应的搅拌速度、反应时间、反应温度、酸解时间、物料配比和反应pH值进行了实验研究。结果表明,搅拌速度、反应时问对反应的影响不大;反应温度取室温;酸解时间、物料配比、反应pH值对反应的影响较大;对反应影响最大的因素是物料配比;最优物料配比是H3PO4：氨二泥：氨水=1：2．1：2．1（质量比）。     

改性呋喃树脂的研制

以苯酚、三聚氰胺为改性剂对呋喃树脂进行了复合改性.用正交实验法,通过测定树脂的粘度、游离甲醛、含氮量和抗拉强度等主要性能指标,考察了原料配比、pH值、温度对产品性能的影响,最终确定了改性树脂的最佳配比和适宜的工艺条件为:糠醇:苯酚:尿素:甲醛:三聚氰胺=0.90:0.30:0.95:2.60:0.03.     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

Western and Eastern culture differences in commercial field

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.     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

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?     

只要努力,不要后悔

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.     

浅谈移民问题

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.     

风的曲线

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.     

团图为数的图中的闭团贯数

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.     

Sister Carrie, an Adherent of Desires

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.