共查询到20条相似文献，搜索用时 31 毫秒
1.
新制备的Cu2(C5H5N)2(C8H7O2)4加入到溶有2-甲基苯甲酸、吡啶的C2H5OH/H2O(1∶1,v/v)混合溶剂中反应,得到新的双核铜配合物Cu2(C5H5N)2(C8H7O2)4晶体,结构经X-衍射法表征.晶体结构中,四个苯甲酸离子羧基八个O原子经syn-syn式桥连二个Cu原子成灯笼状,在轴向分别由二个吡啶分子N配位而形成四方锥形几何结构.分子间沿(010)方向,形成折叠假性的六边形紧密堆积结构.配合物CCDC号:856726. 相似文献
2.
设图G=G(V,E),令函数f:V→{-1,1},f的权w(f)=∑v∈Vf[v],对v∈V,定义f[v]=∑u∈N[v]f(u),这里N[v]表示V中顶点v及其邻点的集合。图G的符号控制函数为f:V→{-1,1}满足对所有的v∈V有f[v]≥1,图G的符号控制数γs(G)就是图G上符号控制数的最小权,称其f为图G的γs-函数。研究了C2n图,通过给出它的一个γs-函数得到了其符号控制数。 相似文献
3.
用苯乙酸做配体合成了苯乙酸铜的配合物,在配合物中,三个苯乙酸根参与配位,而一个苯乙酸根做为平衡离子存在于晶体中,邻啡罗啉提供两个N原子参与配位,形成铜的五配位双核配合物.分子内氢键和分子间氢键将分子连接成三维网状结构. 相似文献
4.
A graph is called claw-free if it does not contain a claw as its induced subgraph. In this paper, we prove the following results : 1 ) If G is a 2-connected claw-free graph on n vertices, then for any vertex υ and any two distinct vertices x and y in V(G) - |υ| , G has a path containing v and all neighbors of v and connecting x and y;2) Let C be the longest cycle in a 3-connected claw-free graph G and H a component of G - C,and if H is connected but not 2-connected, then there exist nonadjacent vertices u and v in H such that |V(C)| ≥3(d(u) d(u)) -2. 相似文献
5.
Objective
A commonly cited, but unproven reason given for the rise in reported cases of child sexual abuse in Sub-Saharan Africa is the “HIV cleansing myth”—the belief that an HIV infected individual can be cured by having sex with a child virgin. The purpose of this study was to explore in Malawi the reasons given by convicted sex offenders for child sexual abuse and to determine if a desire to cure HIV infection motivated their offence.Methods
Offenders convicted of sexual crimes against victims under the age of 18 were interviewed in confidence in Malawi's two largest prisons. During the interview the circumstances of the crime were explored and the offenders were asked what had influenced them to commit it. Each participant was asked the closed question “Did you think that having sex with your victim would cure or cleanse you from HIV?”Results
58 offenders agreed to participate. The median (range) age of offenders and victims was 30 (16-66) years and 14 (2-17) years, respectively. Twenty one respondents (36.2%) denied that an offence had occurred. Twenty seven (46.6%) admitted that they were motivated by a desire to satisfy their sexual desires. Six (10.3%) stated they committed the crime only because they were under the influence of drugs or alcohol. None of the participants said that a desire to cure or avoid HIV infection motivated the abuse.Conclusion
This study suggests that offenders convicted of a sexual crime against children in Malawi were not motivated by a desire to be cured or “cleansed” from HIV infection. A need to fulfil their sexual urges or the disinhibiting effect of drugs or alcohol was offered by the majority of participants as excuses for their behaviour. 相似文献6.
7.
以N,N＇-二四唑胺（H2bta）为配体,合成了未见报道的碱土金属Ca、Sr的含能配合物,并对其进行基础的物化表征。化学分析、元素分析确定配合物的组成为Ca（bta）（H2O）5（1）和Sr（bta）（H2O）5（2）。溶解性实验表明,常温下配合物难溶于水,加热时溶解,不溶于常见的如甲醇,乙腈等有机溶剂。红外光谱分析表明,配体bta2-中N原子参与了配位。热重结果显示,在N2气氛、研究温度范围内配合物都有三个热分解过程,最终分解产物分别为以CaO与SrO为主的残余物。 相似文献
8.
刘大翠 《四川职业技术学院学报》2005,15(4):106-108
本文对硫酸盐还原菌产亚硫酸盐还原酶的发酵工艺条件进行了初步研究,主要内容包括硫酸盐还原菌发酵条件：碳源、氮源、温度、起始pH、装液量及发酵周期等.实验研究表明,以尿素作为氮源,以可溶性淀粉为碳源,C：N比为1：3,在初始pH7.0的条件下,接种量为5%,装液量为1：3（v/v）,35℃摇床培养42h,酶活力可达到16.2U/mL. 相似文献
9.
用苯乙酸做配体合成了苯乙酸铜的配合物,在配合物中,三个苯乙酸根参与配位,而一个苯乙酸根做为平衡离子存在于晶体中,邻啡罗啉提供两个N原子参与配位,形成铜的五配位双核配合物．分子内氢键和分子间氢键将分子连接成三维网状结构． 相似文献
10.
Purpose
Empirical research regarding potential risks and benefits of children's participation in the legal system generally, and in the child dependency legal system in particular, is sparse and mostly characterized by small studies without comparison groups. The current study was designed to address the following questions regarding children's participation in dependency court hearings: (1) Is attending court harmful to children? (2) Is attending court beneficial to children? (3) Is judicial behavior with the child in the courtroom related to potential harms or benefits? and (4) Are there age differences in children's reactions?Method
The authors measured children's reactions to attending dependency review hearings (n = 43) and compared them to a sample of children who did not attend their hearings (n = 50). One to 2 weeks following review hearings, both groups of children were interviewed about their reactions to the court process.Results
Children who attended their hearings reported more positive feelings about the dependency process (e.g., trust in judge, perceived fairness, and more comfort with their guardians ad litem and caseworkers). For children who attended, there was no evidence of high distress immediately preceding or following their hearings. Court observations revealed that more active engagement by judges was related to positive responses from the children. Most children, including both children who attended hearings and those who did not, believed that all children should be able to attend their hearings.Conclusion
Overall, the findings suggest that policies encouraging children's attendance at dependency hearings are viewed positively by and not harmful to children. 相似文献11.
Analytic and heuristic processing influences on adolescent reasoning and decision-making 总被引：1，自引：0，他引：1
Klaczynski PA 《Child development》2001,72(3):844-861
12.
孙小强 《赣南师范学院学报》2008,29(3):41-44
利用多元函数方向导数的概念与矩阵变换等方法推广了C.-R.方程,给出了解析函数f（z）=u（x,y）＋iv（x,y）的实部与虚部关于任意两个方向v1,v2的方向导数（偏du/偏dv1,偏dv/偏dv1）与（偏du/偏dv2,偏dv/偏dv2）之间的关系.利用所得结果对复变函数可微的一个充要条件做了改进.相应的结论对解析函数也成立. 相似文献
13.
设G是阶数不小于2的简单连通图,G的k-正常全染色,f称为是邻点可区别的,如果对G的任意相邻的两顶点其点的颜色及关联边的颜色构成的集合不同.这样的k中最小者称为是G的邻点可区别全色数.本文得到了△(G)=6的2-连通外平面图的邻点可区别全色数. 相似文献
14.
15.
用V=π∫baf2(x)dx可求得连续曲线y=f(x)的弧AB与直线x=a,x=b及x轴所围成的平面图形绕x轴旋转一周得到的旋转体的体积.若x轴推广为一般的直线y-yo=k(x-xo),其它条件不变,其旋转体的体积可由V=π/(1 k2)3/2∫ba[kx-kx0-f(x) y0]2|1-kf'(x)| dx求得. 相似文献
16.
以乙酰丙酮、2,6-二异丙基苯胺(或2,6-二甲基苯胺)和对甲苯磺酸为原料通过两步反应高产率的合成了N,N'-二(2,6-二异丙基苯基)-2,4-戊二亚胺(1)和N,N'-二(2,6-二甲基苯基)-2,4-戊二亚胺(2),产率分别为78%和72%,并用元素分析和1HNMR对产物进行了结构表征. 相似文献
17.
首先合成了标题化合物C20H22N2O2,用元素分析、核磁共振和X-射线单晶衍射法进行了表征和结构分析,该化合物为三斜晶系,空间群：P-1。晶胞参数a=9．846（6）A,b=10．198（3）（13）A,c=132679（17）A,α=78．00（3）,β=76．390（5）,γ=62．938（5）,Z=2,V=910．0（7）A3,Dc=1．177g／cm3,F（000）=344,μ（MoKα）=0．763mm-1,R1=0．0809,wR2=0．1958．该化合物中除了烷基链的所有原子基本都在一个平面,并且依靠∏-∏芳环堆积作用组合成3D网状结构。 相似文献
18.
The study of educational innovations has become increasingly important in education research as many countries around the world have embarked on education reforms that aim to change both the goals and practices in education. There is also a general expectation that such innovations can be leveraged or supported by the use of information and communication technology (ICT) in the learning and teaching process. However, comparative studies of innovations are relatively rare. SITES M2, as an international comparative study of innovative pedagogical practices involving 28 participating systems, thus faced important methodological challenges the solution of which was no less an innovation in itself. This paper examines the methods of analysis used and the kind of research findings that resulted from the work of three research teams that had conducted comparisons of the case studies of innovation collected, including the work of the SITES M2 International Coordinating Centre (ICC). Even though all three studies attempted to examine similarities and differences across multiple case studies, the analysis conducted by the ICC looked for characterizations of the innovations while the other two studies developed meaningful ways to compare the cases in terms of levels of innovation across a number of dimensions. In discussing the methodological differences across these studies, this paper pays special attention to how one could compare different innovations in terms of their levels or extents of innovation and what such comparisons may contribute to our learning from technology-supported education innovations. 相似文献
19.
本介绍了用N，N－二甲基吡啶（DMAP）为催化剂合成N^2,9-二乙酰基鸟嘌呤的新方法，并对催化剂及其他因素的影响进行了研究，该方法具有操作简便，反应时间短，产品收率高达76％的优点。 相似文献