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1.
舒元梯 《乐山师范学院学报》2005,20(12):62-65
基于元素的Pauling电负性、原子成叮键的电子数，原子直接键连的氢原子数目和原子在形成离域π键时所提供的Pz电子数，定义了一种原子点价公式，构建了分子连接性指数。研究了脂肪醇对蝌蚪麻醉活性，沙蜀幼虫麻醉活性，藤壶幼虫麻醉活性，番茄植物毒性和红蜘蛛毒性与分子连接性指数^1x的相关性。研究了取代苯并咪唑抗菌活性，取代苯甲醇对黑曲霉幼虫抑制活性分别同分子连接性指数的相关性。结果表明：分子连接性指数具有良好的结构选择性和性质相关性，可用于预测其它取代苯并咪唑、取代苯甲醇和脂肪醇的生物活性。 相似文献
2.
应用CNDO／2量子化学方法计算了20个氯代酚类化合物的电子结构，并运用计算机自编程序进行相关分析和逐步回归分析，探讨了氯代酚类化合物的电子结构对发光细菌（Microtox)半致死量负对数－logEC50之间的定量关系，得出了苯环上各个碳原子的π电荷之和（ΣQPR）与－logEC50之间的回归方程：－logEC50=-1.017 0.260ΣQPR，结果表明：ΣQPR越大，则氯代酚类化合物对Microtox的毒性越大，据此可通过测量化合物的ΣQPR来预测氯代酚类化合物对Microtox的毒性。 相似文献
3.
以OCDF和12378-PeCDF为例,探究了海绵铁脱氯还原降解二噁英的方法。对比了超声、海绵铁+超声、海绵铁/银+超声三种处理二噁英的实验方法,并对海绵铁/银+超声处理方法中二噁英浓度、海绵铁投加量以及超声时间等条件进行了优化,探索海绵铁处理二噁英的方法。实验结果表明,在海绵铁/银+超声的体系条件下还不能脱氯还原降解二噁英,还需要做进一步深入的探究。 相似文献
4.
一种新的连接性拓扑指数与卤代苯毒性的定量关系 总被引：1，自引：0，他引：1
借助元素的有效主量子数改造了原子点价,定义了一个新的表征卤代苯结构的分子连接性指数Xz*,用它研究了17种卤代苯化合物对生物的毒性,通过最小二乘法建立了相应的定量结构———毒性相关方程,其相关系数为0.990,并在α=0.01水平下通过F检验,结果表明Xz*计算简单,物理意义明确,预测结果令人满意,为该类化学品的环境危险性评价提供了依据. 相似文献
5.
1化合价是元素形成化合物时表现出来的一种性质
化学上用“化合价”来表示原子问相互化合的数目。如：在反应2Na＋Cl2=2NaCl中,作为反应物的钠原子与氯原子的个数比总是1：1参与反应。这是因为在化学反应中,元素原子的最外电子层总是要趋于八个电子的稳定结构,即元素的原子一定会得到或失去一定数目的最外层电子或形成共用电子对以达到稳定结构,不同元素的原子问相互化合时符合一定的个数比,才能形成稳定的化合物。 相似文献
6.
合成了一新型氯桥联铜配位聚合物[(μ-Cl)Cu(BBPY)]＋ n [BBPY：2,6-二(2-苯并咪唑基)吡啶],经 X-射线衍射法测定其结构,属单斜晶系,P2(1)/c 空间群,由氮、氯原子与铜(II)配位,氮对铜(II)配位形成两个五元环,构成中心铜与配位原子的畸变锥形结构,通过氯原子的 Cu(μ-Cl)Cu 桥联作用形成一维链铜配位聚合物。 相似文献
7.
1.从前面所学的知识可知,纯净物组成是固定不变的,每一种纯净物组成的化学式只有一个,即形成化合物的元素有固定的原子个数比.例如: 化学上用"化合价"来表示原子之间相互化合的数目.如:在2Na+Cl2=2NaCl 反应中,反应物的钠原子与氯原子的个数比总是1:1.这是因为在化学反应中,元素的原子最外电子层总是要趋于八个电子的稳定结构,即元素的原子会得到或失去一定数目的最外 相似文献
8.
烃、醇和醚沸点的分子拓扑研究 总被引：1，自引：0，他引：1
舒元梯 《内江师范学院学报》2008,23(12)
基于元素的Pauling电负性,原子成σ键的电子数,原子直接键连的氢原子数目和原子在形成离域π键时所提供的Pz电子数,定义了一种原子点价公式,构建了分子连接性指数.研究了烷烃、单烯烃、单炔烃、苯和其同系物,饱和一元醇,多元醇和脂肪醚沸点同其分子连接性指数的相关性.结果表明:分子连接性指数具有良好的结构选择性和性质相关性,可用于预测有机化合物的沸点. 相似文献
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10.
甲烷是正四面体结构,碳原子位于正四面体的中心,4个氢原子分别位于正四面体的4个顶点,当甲烷分子上的1、2或3个氢原子被氯原子取代后,由于原子之间的相互影响,键长、键角都发生了变化,所以就不再是正四面体结构了,当4个氢原子都被氯原子取代之后,4个碳氯键的键长相等,空间伸展方向对称,又形成了正四面体结构。 相似文献
11.
YAN Jian-hua PENG Zheng LU Sheng-yong LI Xiao-dong CEN Ke-fa 《浙江大学学报(A卷英文版)》2006,7(11):1896-1903
INTRODUCTION Polychlorinated dibenzodioxins and poly- chlorinated dibenzofurans (PCDDs/Fs) are some major toxic substances unintentionally produced mainly from municipal solid waste incineration (MSWI). Attention has been focused on the best way for controlling and regulating such emissions. Among flue gas treatment technologies for post combustion zone emission control (Buekens and Huang, 1998; McKay, 2002), activated carbon adsorption (ACA) and techniques involving physical adsorp… 相似文献
12.
Ａｂｓｔｒａｃｔ : ＩｎｃｉｎｅｒａｔｉｏｎａｓａｍｅｔｈｏｄｏｆｒｅｄｕｃｉｎｇＭｕｎｉｃｉｐａｌＳｏｌｉｄＷａｓｔｅ (ＭＳＷ)ｖｏｌｕｍｅａｎｄｒｅｃｏｖｅｒｙｏｆｅｎｅｒ ｇｙｈａｓｂｅｅｎｄｅｖｅｌｏｐｅｄｇｒａｄｕａｌｌｙｉｎＣｈｉｎａ .Ｍｏｒｅａｔｔｅｎｔｉｏｎｉｓｐａｉｄｏｎｐｏｌｙｃｈｌｏｒｉｎａｔｅｄｄｉｂｅｎｚｏ ｐ ｄｉｏｘｉｎｓａｎｄｐｏｌｙｃｈｌｏｒｉｎａｔｅｄｄｉｂｅｎｚｏｆｕｒａｎｓ (ＰＣＤＤ Ｆｓ)ｆｏｒｍｅｄｉｎＭＳＷｉｎｃｉｎｅｒａｔｉｏｎｐｒｏｃｅｓｓ .Ｔｈｉｓｐ… 相似文献
13.
Xu Xu Li Xiao-dong Yan Jian-hua Lu Sheng-yong Gu Yue-ling Chi Yong Cen Ke-fa 《浙江大学学报(A卷英文版)》2001,2(3):278-283
Incineration as a method of reducing Municipal Solid Waste (MSW) volume and recovery of energy has been developed gradually
in China. More attention is paid on polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans, (PCDD/Fs) formed in MSW incineration process. This paper presents results of the
analysis of PCDD/Fs in the residues of a fluidized bed incinerator co-firing MSW and coal in the Yuhang Thermal Power Plant.
The effects of operation conditions and the wet scrubber system on PCDD/Fs formation were also analyzed. PCDD/Fs emitting
from the smoke stack was 0.92 I-TEQ ng/Nm3. After the wet scrubber emission of dioxins increased and the shifting of homologue profiles in flue gas was also observed,
PCDFs were not detected in the incinerator residues. From this, we can see that in the MSW incineration process, the formation
mechanism of PCDFs was different from that of PCDDs. The results will benefit further research on the optimal operation of
incinerator and control of PCDD/Fs emission from the MSW incinerator.
Project supported by the Special Funds for Major State Basic Research Projects 973. (G1999022211), and Natural Science Foundation
of China (No. 59836210, No. N1986 2598780472). 相似文献
14.
Ke Shao Jian-hua Yan Xiao-dong Li Sheng-yong Lu Mu-xing Fu Ying-lei Wei 《浙江大学学报(A卷英文版)》2010,11(5):363-369
The effects of SO2, SO3 on de novo synthesis of polychlorinated dibenzo-p-dioxins （PCDDs） and dibenzofurans （PCDFs） were studied using model fly ashes incorporating copper oxide and activated carbon. It was found that the inhibitive effect of SO2 on PCDD/Fs formation is similar to that of SO3. To investigate the inhibition mechanism, CuSO4 formations from both CuO and CuCl2 were examined. The ability of SO3 to convert CuCl2 and CuO on a silica support into sulfate is much stronger than that of SO2. However, replacing silica by activated carbon leads to a much high conversion of CuCl2 to CuSO4 in the presence of SO2. The promotion by activated carbon is explained by the reduction of CuCl2 to Cu2Cl2 and the eventual conversion of Cu2Cl2 into CuSO4 is the main inhibition mechanism of SO2 on de novo synthesis of PCDD/Fs. 相似文献
15.
Polychlorinated dibenzo-p-dioxins and dibenzofurans in flue gas emissions from municipal solid waste incinerators in China 总被引：2，自引：0，他引：2
Tong CHEN Yue-ling GU Jian-hua YAN Xiao-dong LI Sheng-yong LU Hui-fen DAI Ke-fa CEN 《浙江大学学报(A卷英文版)》2008,9(9)
Polychlorinated dibenzo-p-dioxins and furalls(PCDD/Fs)emissions in flue gas from two types of municipal solid waste incinerators(MSWIs)most commonly used in China were investigated in this study.The selected incinerators include two grate-type MSWIs:MSWl-A(350 t/d)and MSWI-B(150 t/d),and two fluidized bed MSWIs:MSWI-C(400 t/d) and MSWI-D (400 t/d),which are all equipped with semi-dry lime scrubber and bag filter except MSWI-D equipped with cyclone and wet scrubber(WS)as air pollutant conffol device(APCD).Results indicated that the emission concentration and the international toxic equivalents(I-TEQs)of the PCDD/Fs from the stacks were in the range of 1.210～10.273 ng/Nm3 and 0.019～0.201 ngI-TEQ/Nm3,respectively.They were greatly lower than the emission regulation standard of PCDD/FS in China(1.0 ng I-TEQ/Nm3).However,only the PCDD/Fs emission Ievel from MSWI-C Was below 0.1 ng I-TEQ/Nm3.Although the homologue profiles were distinct,the contributions of the 2,3,7,8-subsituted congenem to the total I-TEQ were similar among all the investigated MSWIs.Two major 2,3,7,8-substituted congeners,2,3,4,7,8-PeCDF and 1,2,3,7,8-PeCDD,account for 47% and 9%(average values)of the total I-TEQ values,respectively.The correlation between PCDD/Fs levels and composition of flue gas Was also discussed. 相似文献
16.
Tong Chen Yue-ling Gu Jian-hua Yan Xiao-dong Li Sheng-yong Lu Hui-fen Dai Ke-fa Cen 《浙江大学学报(A卷英文版)》2008,9(9):1296-1303
Polychlorinated dibenzo-p-dioxins and furans （PCDD/Fs） emissions in flue gas from two types of municipal solid waste incinerators （MSWIs） most commonly used in China were investigated in this study. The selected incinerators include two grate-type MSWIs： MSWI-A （350 t/d） and MSWI-B 050 t/d）, and two fluidized bed MSWIs： MSWI-C （400 t/d） and MSWI-D （400 t/d）, which are all equipped with semi-dry lime scrubber and bag filter except MSWI-D equipped with cyclone and wet scrubber （WS） as air pollutant control device （APCD）. Results indicated that the emission concentration and the international toxic equivalents （I-TEQs） of the PCDD/Fs from the stacks were in the range of 1.210-10.273 ng/Nm^3 and 0.019-0.201 ng I-TEQ/Nm^3, respectively. They were greatly lower than the emission regulation standard of PCDD/Fs in China （1.0 ng I-TEQ/Nm^3）. However, only the PCDD/Fs emission level from MSWI-C was below 0.1 ng I-TEQ/Nm^3. Although the homologue profiles were distinct, the contributions of the 2,3,7,8-subsituted congeners to the total I-TEQ were similar among all the investigated MSWIs. Two major 2,3,7,8-substituted congeners, 2,3,4,7,8-PeCDF and 1,2,3,7,8-PeCDD, account for 47% and 9% （average values） of the total I-TEQ values, respectively. The correlation between PCDD/Fs levels and composition of flue gas was also discussed. 相似文献
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18.
The programme director and the Teaching Excellence Framework: How do we train the former to survive the latter? 
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下载免费PDF全文 Ruth Massie 《Higher Education Quarterly》2018,72(4):332-343
The programme director undertakes a key role within UK universities in linking the department, or school, directly with the student and their experience of the university. The role is multifaceted and complex with a number of competencies required to successfully undertake it. Furthermore, the UK’s Teaching Excellence Framework (TEF) was fully introduced in 2016 and utilises existing measures such as student satisfaction, retention rates and destination of leavers as a proxy for teaching excellence. Many of these metrics are also part of the day‐to‐day concerns of programme directors within universities. This research surveyed 89 programme directors on the training they have received to carry out their role and how it links to the TEF outcomes. The article argues that there is insufficient training for programme directors and an increase in training may have a beneficial outcome for a university’s TEF results. 相似文献
19.
Previous research has shown that postshock acceleration of baseline responding, which normally results from exposure to a shock/no-shock autocontingency, is eliminated when a suppressive tone-shock contingency is simultaneously presented (Davis, Memmott, & Hurwitz, 1975). Three experiments were performed to explore this inability to produce joint suppressive/ accelerative control by compound tone-shock and shock/no-shock contingencies. Progressively degrading the tone-shock contingency in Experiment 1 maintained conditioned suppression and resulted in asymptotic levels of postshock acceleration in all degraded groups. Evidence for accelerative control by the autocontingency was also recorded in a control group that received a totally reliable tone-shock relation. Experiments 2 and 3 pursued this latter finding, which is in direct conflict with our earlier results. The appearance of joint suppressive/ accelerative control by tone-shock and shock/no-shock contingencies appears to be related to the number of shock trials given per session; moreover, relatively small differences in trial density (e.g., three trials per 22.5 min vs. three trials per 30 min) are critical to establishing joint autocontingency control. The importance of shock rate is discussed with regard to the relative waiting time hypothesis, an alternative model of Pavlovian control, as well as to previously reported conditioning failures involving compound suppressive/accelerative procedures. 相似文献
20.
应用G98W程序包中的量子化学密度泛涵（DFT）方法，在B3LYP／6—31G（d）水平上，对51种二苯并呋喃及其衍生物（PCDFs）进行几何构型全优化。优化后所得分子的最高占据轨道能量、二苯并呋喃环上1，2，3，7四个原子静电荷密度作为PCDFa分子结构描述符。应用支持向量机构建多氯代二苯并呋喃logKow的定量构效（QSAR）关系模型，所建模型的预测值与实验值吻合的很好，经留一交叉校检法检验该模型，该模型具有良好的稳健性，有一定的应用价值． 相似文献