排序方式: 共有20条查询结果,搜索用时 15 毫秒
11.
12.
碧冬茄的挥发性化学成份鉴定及其驱蚊活性研究初报 总被引:1,自引:0,他引:1
碧冬茄的挥发性化学成份鉴定及其驱蚊活性研究初报么恩云,李正名,平霄飞,施红林,毕富春,王文丽(元素有机化学国家重点实验室,南开大学元素有机化学研究所天津300071)杨瑞华(南开大学生物系天津300071)在天然植物中蕴藏着极其丰富的生理活性物质。近... 相似文献
13.
Three kinds of metal catalysts Ni/D_4, Ni-Mn/D_4, Ni-Mn-La/D_4, wrapped in organosilicon compound were prepared by metal vapor synthesis. Their feature was characterized with XRD, TEM, XPS, FMR and static magnetic measurement. The metal particle size in catalysts was less than 3.5 am. The results of XPS showed that the metals in the catalysts existed in zero and other valent state. Inner metal, as an organosilicon compound folded around the metal particle, was protected from oxidation. FMR and static magnetic measuremeat revealed that metal particles were spheroidal and of superparamagnetism. Of all the caralysts the catalytic activity of Ni-Mn-La/D_4 was the highest in hydrogenating furfuraldehyde into furfuralcohol. 相似文献
14.
硫代磷酰胺酯类化合物的合成及其结构与除草活性的定量关系 总被引:1,自引:1,他引:1
O-乙基O-芳基N-异丙基硫代磷酰胺酯(Ⅰ)具有除草活性,为了研究这类化合物的结构与活性的定量关系,用O-乙基O-芳基硫代磷酰氯与异丙胺在40%NaOH存在下于0℃反应,制得了30余个化合物Ⅰ,收率及纯度均较理想。并发现化合物的活性大小与苯环上取代基密切相关。根据Hansch方程,发现化合物Ⅰ抑制稗草生长的活性与其苯环上取代基的亲脂性参数π,空间效应参数E_s,电子效应参数σ及场效应参数F密切相关。分别用实验测得的△R_m及△δ_p代替π及σ和F进行回归分析,亦可得较好的相关关系。文中讨论了该两项实验参数在结构与活性定量关系研究中的实用意义。 相似文献
15.
仪征市行政审批电子系统自2008年10月正式运行以来,运用"电子眼"加强对行政权力行使的监督制约,对进入行政服务中心的32个部门304个审批项目实施全程监察,对超期、退办事件等异常情况,系统发送督办、催办单与询问函,再通过短信平台,向相关负责人发送提醒短信,及时督促相关人员按期办结相关事项.初步形成了"网上受理、内网办理、电子监控、网上反馈"的工作机制.同时,运用"电子眼"功能,对进驻行政服务中心各窗口人员的工作情况进行视频记录,并不定期的进行通报. 相似文献
16.
仪征市行政审批电子系统自2008年10月正式运行以来,运用“电子眼”加强对行政权力行使的监督制约,对进入行政服务中心的32个部门304个审批项目实施全程监察,对超期、退办事件等异常情况,系统发送督办、催办单与询问函,再通过短信平台,向相关负责人发送提醒短信,及时督促相关人员按期办结相关事项。初步形成了“网上受理、内网办理、电子监控、网上反馈”的工作机制。同时,运用“电子眼”功能,对进驻行政服务中心各窗口人员的工作情况进行视频记录,并不定期的进行通报。 相似文献
17.
本文分别以三(对甲基苯基)膦,亚磷酸三(对甲基苯基)酯,亚磷酸三(对氯苯基)酯,亚磷酸三(邻甲氧基苯基)酯,亚磷酸三苯基酯等为配位体,以二羰基乙酰丙酮铑为催化剂母体,研究1—庚烯醛化反应的动力学和反应产物的分布,用动力学结果和测得的催化剂体系的红外光谱羰基伸缩振动频率与文献[1]结果比较,进一步说明烯醛化反应的速率不仅决定于其反应的控制步骤,而且与反应体系中活化络合体的浓度有关.亚磷酸三(3,4-二甲基苯基)酯有利于活化络合体的形成,其作为配位体时,醛化反应的速率较其它配位体高得多,同时由于其较大的立体化学效应,提高了对产物中直链醛的选择性. 相似文献
18.
O-Aryl O-ethyl N-isopropyl phosphoramidothioates (Ⅰ) have herbicidal activity. In order to study the relationship between structures and activities of these compounds, more than thirty compounds (Ⅰ) have been prepared by the reaction of O-aryl O-ethyl phosphorochloridothioates with isopropylamine in the presence of 40% NaOH at 0℃. The intermediates, phosphorochloridothioates, were prepared separately from a large excess of O-ethyl Phosphorodichloridothioate and various substituted phenols in the presence of 40% NaOH and a catalyrical amount of Et_3N at 0—5℃. As a result, higher purity and good yields were obtained.It was found that the activity of these compounds was highly dependent upon the substituents attached to the benzene ring with respect to the characteristic parameters π, E_s, σ and F by using Hansch's equation.It was indicated that hydrophobic (π), steric (E_s), and electronic (σ and F) effects of the substituents on the ring in those molecules seem to be of considerable importance i 相似文献
19.
20.