拉普拉斯变换的数值逆在线性偏积分微分方程中的应用

给出一种求一类线性偏积分微分方程u_t(x,t)-β(t-s)u_(xx)(x,s)ds=f(x,t)数值解的方法,空间x方向采用孙志忠教授在文[3]中的六点隐格式离散,时间t方向采用拉普拉斯变换数值逆,得出数值解的精度较高,计算也比较简便。     

浅谈六类布线的问题

在六类布线中的任何安装错误或走所谓的“捷径”,都有可能导致测试勉强合格或不合格,因此,大多数制造商在产品出售时,都建议安装商严格遵守布线标准文件中规定的安装方法及随产品提供的建议方法．这也许是六类布线安装标准出台前保证布线质量的有效方法之一。     

Fabrication and magnetic properties of Co nanowire arrays of different crystal structures

It is important to find some developing high-density magnetic recording materials in magnetic recording field with the development of information and technique, in which vertical magnetic recording is a very important way and has received considerable attention[1—3]. The vertical magnetic recording materials require high squareness, suitable coercivity, and small size of storage element[4]. Someone used nanoporous anodic aluminum oxide as templates to fabricate uniform arrays of multi magneti…     

通海海菜花的核型研究

首次报道产于我国云南省的通海海菜花 (Otteliaacuminatavar.tonhaiensish .Li)的体细胞染色体数目和核型 ( 2n =2x =2 2 =1 8m 2sm 2st) .属“2B”型 ,与海菜花属 (Ottelia)的核型非常相近 ,这为进一步研究水鳖科海菜花属的系统演化提供了重要的细胞学资料     

X－ray reflectivity investigation of the foam bilayer film formed by hexaethylene glycol dodecyl ether

When the thickness of soap foam film varies in adefinite region, color changes of a soap bubble will be observed due to the interference of light. Black soap films are the final stages of thinning of soap films due to the drainage of water in the absence of evaporation and are generally formed from solutions of an ionic surfactant in the presence of salt. After a bubble is formed, in the beginning the soap film is relatively thick and it appearswhite; then the film thins gradually and finally …     

NMR study on self-assembled cage complex of hexamethylenetetramine and cucurbit[n]urils

Self-assembled complexes between cage com-pounds cucurbit[n = 5—8]urils and hexamethylenetetramine were studied by using NMR techniques. Experimental results reveal that hexamethylenetetramine can lid cucurbit[5]uril to forming self-assembled capsules in which nothing is encap-sulated yet; the cavity of the cucurbit[7]uril can accommo-date a hexamethylenetetramine molecule to form a self- assembled host-guest inclusion. Moreover, both the cavity interaction of the cucurbit[7]uril with hexamethylenetetra-mine稨Cl and the portal interaction of the dipole carbonyl of the cucurbit[7]uril with hexamethylenetetramine稨Cl lead to form self-assembled capsules in which the hexamethylene-tetramine稨Cl are encapsulated in the hexamethylenetetra-mine稨Cl lidded cucurbit[7]uril. Although the structures of the portal and cavity to cucurbit[5]uril are similar, there is no obvious interaction between decamethylcucurbit[5]uril and hexamethylenetetramine, and also between cucurbit [6]uril or cucurbit[8]uril and hexamethylenetetramine.     

山东省自然辩证法研究会召开第六次代表大会

8月21日-23日,山东省自然辩证法研究会第六次代表大会在济南山东经济学院召开。中国自然辩证法研究会副秘书长王玉平研究员,中共山东省委宣传部副部长张全新教授,山东省科学技术协会学会部邵新贵部长,山东省社会科学界联合会正厅级巡视员、原副主席包心鉴教授,山东省民政厅民间组织管理局吴运亮副局长等领导同志出席开幕式并讲话。全省各地50余名会员代表参加了会议。会议经过充分酝酿,民主选举产生了新一届理事会。山东经济学院党委书记张体勤教授当选为理事长,山东大学文史哲研究院副院长马来平教授当选为常务副理事长兼秘书长。刘树伟教…     

市场潜力大的六类植物

观赏植物 此类植物有异形枣、葫芦枣、茶壶枣等,彩色水果(彩色葡萄等),彩色甜椒,彩色作物(彩色玉米、彩色花生、彩色地瓜等).     

纳米Ni粉末的制备及相转变研究

利用柠檬酸盐分解法制备前驱体，在惰性气氛中进行热处理，合成了六角密排结构的纳米Ni粉末．并利用XRD、XRD高温测试手段对产物的相转变和结构变化过程进行了研究．结果表明，随着热处理温度的升高，纳米镍粉发生了六角密排到面心立方的结构相变，相变温度为350℃左右．此外，对转变后的面心立方相的镍粉进行进一步热处理，发现随着热处理温度的提高，晶粒尺寸和晶胞参数会逐渐增大．