期刊文献+
共找到7篇文章
< 1 >
每页显示 20 50 100
相对活度在物理化学课程中的应用
1
作者 宁爱民 《大学化学》 CAS 2015年第2期34-38,共5页
介绍了相对活度的概念和化学势表达式的通式在物理化学课程中的一些应用,有助于学生深刻理解和系统掌握相关知识,对提高教师的授课效率和学生的学习效率均有一定的帮助。
关键词 物理化学 相对活度 化学势 标准状态
下载PDF
绝对活度的统计意义
2
作者 李汝雄 《武汉工程大学学报》 CAS 1986年第1期36-38,共3页
在国际单位制中定义绝对活度入;λ=exp(μ/RT)(1)而将活度a(或称相对活度)定义为绝对活度与标准绝对活度λφ之比:a=λ/λφ(2)标准绝对活度定义为:λφ=exp(μφ/RT)(3)式中μφ为标准态下的化学位。绝对活度是一个新概念,它的引入不... 在国际单位制中定义绝对活度入;λ=exp(μ/RT)(1)而将活度a(或称相对活度)定义为绝对活度与标准绝对活度λφ之比:a=λ/λφ(2)标准绝对活度定义为:λφ=exp(μφ/RT)(3)式中μφ为标准态下的化学位。绝对活度是一个新概念,它的引入不仅为热力学推导带来方便。 展开更多
关键词 绝对活度 统计力学 相对活度 标准态 配分函数 化学位 粒子数 阿佛加德罗常数 物系 基态能量
下载PDF
不同制备工艺菜籽油的风味成分比较研究 被引量:16
3
作者 袁桥娜 涂梦婕 +4 位作者 董志文 何东平 罗质 胡传荣 高盼 《中国油脂》 CAS CSCD 北大核心 2020年第8期32-38,共7页
采用传统工艺(蒸炒、压榨工艺和蒸炒、压榨、脱胶工艺)和美拉德生香工艺分别制备菜籽油(菜籽油甲、菜籽油乙和菜籽油丙),采用顶空固相微萃取与气相色谱-质谱联用对3种工艺菜籽油的挥发性风味成分进行分析,采用气味活度值和相对活度值确... 采用传统工艺(蒸炒、压榨工艺和蒸炒、压榨、脱胶工艺)和美拉德生香工艺分别制备菜籽油(菜籽油甲、菜籽油乙和菜籽油丙),采用顶空固相微萃取与气相色谱-质谱联用对3种工艺菜籽油的挥发性风味成分进行分析,采用气味活度值和相对活度值确定对3种菜籽油风味贡献最大的物质。结果发现:菜籽油甲、菜籽油乙、菜籽油丙分别鉴定出18、29、21种挥发性成分;菜籽油甲、菜籽油丙的整体风味评分接近,略高于菜籽油乙;菜籽油甲、菜籽油乙风味成分中腈类物质的含量明显高于菜籽油丙,而吡嗪类和醛类物质含量明显低于菜籽油丙;对菜籽油甲、菜籽油乙、菜籽油丙风味贡献最大的物质分别为2-噻吩甲醛、3,5-二乙基-2-甲基吡嗪和3-甲基丁醛。 展开更多
关键词 菜籽油 制备 美拉德反应 风味成分 相对活度
下载PDF
Effect of Relative Humidity on Adsorption of Formaldehyde on Modified Activated Carbons 被引量:25
4
作者 李晶 李忠 +2 位作者 刘冰 夏启斌 奚红霞 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2008年第6期871-875,共5页
This work mainly involves the study of effect of relative humidity on adsorption of formaldehyde on the activated carbons modified with organosilane solution. Modification of activated carbons was carded out by impreg... This work mainly involves the study of effect of relative humidity on adsorption of formaldehyde on the activated carbons modified with organosilane solution. Modification of activated carbons was carded out by impregnating activated carbon with organosilane/methanol-containing solutions. The breakthrough curves of formaldehyde in the packed beds of original and modified activated carbons were measured, respectively, at relative humidity of 30%, 60%, and 80%. Temperature-programmed desorption (TPD) experiments were used to estimate the activation energy for desorption of formaldehyde from the activated carbon. Results showed that the relative humidity had strongly influence on breakthrough curves of formaldehyde in the packed beds. The higher the relative humidity of gas mixtures through the packed beds was, the smaller the breakthrough time of formaldehyde became. The use of organosilane compounds to modify surfaces of the activated carbon can enhance the interaction between formaldehyde and the surfaces, and as a result, the breakthrough times of formaldehyde in the packed beds of the modified activated carbon were longer than that in the packed bed of the unmodified activated carbon. 展开更多
关键词 activated carbon FORMALDEHYDE breakthrough curve desorption activation energy
下载PDF
Implication of Surface Fractal Analysis to Evaluate the Relative Sensitivity of Topography to Active Tectonics,Zagros Mountains, Iran 被引量:4
5
作者 Ali Faghih Ahmad Nourbakhsh 《Journal of Mountain Science》 SCIE CSCD 2015年第1期177-185,共9页
Fractal geometry is increasingly becoming a useful tool for modeling and quantifying the complex patterns of natural phenomena. The Earth's topography is one of these phenomena that have fractal characteristics. T... Fractal geometry is increasingly becoming a useful tool for modeling and quantifying the complex patterns of natural phenomena. The Earth's topography is one of these phenomena that have fractal characteristics. This paper investigates the relative sensitivity of topography to active tectonics using ASTER Global Digital Elevation Model. The covering divider method was used for direct extraction of surface fractal dimension(D surf) to estimate the roughness-surface of topography with aid of geographic information system(GIS)techniques. This evaluation let us highlight the role of the geomorphic and tectonic processes on the spatial variability of fractal properties of natural landforms.Geomorphic zones can be delineated using fractal dimension mapping in which variability of surface fractal dimension reflects the roughness of the landform surface and is a measure of topography texture. Obtained results showed this method can be a quick and easy way to assess the distribution of land surface deformation in different tectonic settings. The loose alluvial deposits and irregularities derived by tectonic activity have high fractal dimensions whereas the competent formations and higher wavelength folded surfaces have lower fractal dimensions.According to the obtained results, the Kazerun Fault Zone has a crucial role in the separation of the Zagros Mountain Ranges into the different lithological,geomorphological and structural zones. 展开更多
关键词 Surface fractal analysis TOPOGRAPHY Active tectonics Kazerun Fault Zone ZAGROS Iran
下载PDF
Research on the Inert Dust against Phosphine Resistance of Cryptolestes Ferrugineus 被引量:1
6
作者 Yanyu Li Yang Cao Guangtao Li 《Journal of Life Sciences》 2011年第5期400-404,共5页
Laboratory tests were carried out in order to evaluate the efficacy of five inert dust (Puliangtai, G-1, G-2, G-3 and G-4) against the high level phosphine resistance Cryptolestesferrugineus (Stephens). The relati... Laboratory tests were carried out in order to evaluate the efficacy of five inert dust (Puliangtai, G-1, G-2, G-3 and G-4) against the high level phosphine resistance Cryptolestesferrugineus (Stephens). The relative phosphine resistance of two strains of Cryptolestesferrugineus (Stephens) was measured by the method of knockdown at 2 mg/L of phosphine. The insects were exposed to the five inert dust on filter paper inside petri dishes for 1 day at 30 ±1℃and 65 ±1% relative humidity. Then, the adults were held for 4 days with food at the same conditions without inert dust in surface bioassay. Also, they were placed in 25 ±1℃ and 65 ±1% relative humidity in grain bioassay. In surface bioassay, two strains (JXCF and YYCF) ofCryptolestesferrugineus (Stephens) were susceptible to the five inert dust at 0.08 g/m2 and 0.1 g/m2. G-3 appeared the most effective treatment against both strains, since its efficacy was 3-6 times higher than the other four inert dust tested. YYCF strain was more susceptible than JXCF, with 1-4 times higher mortality level. This research indicated that inert dusts were effective on phosphine-resistance Cryptolestesferrugineus (Stephens) populations. 展开更多
关键词 Inert dust Cryptolestesferrugineus PHOSPHINE resistance.
下载PDF
共聚合反应
7
作者 冯新德 《高分子学报》 SCIE CAS 1959年第5期232-250,共19页
(一) 如果把二种烯类单体放在一起聚合,而得到的聚合物并不是各个单体各自聚合的混合物,而是包含着二种单体链节的新型聚合物,这种聚合物叫做共聚物,得到共聚物的聚合反应叫做共聚合反应。因为聚合物的物理及机械性能决定于长链中单体... (一) 如果把二种烯类单体放在一起聚合,而得到的聚合物并不是各个单体各自聚合的混合物,而是包含着二种单体链节的新型聚合物,这种聚合物叫做共聚物,得到共聚物的聚合反应叫做共聚合反应。因为聚合物的物理及机械性能决定于长链中单体链节的性能,相对数量以及排列方式,所以共聚合反应便具有非常重要的工业意义,因为可以借此改进聚合物性能来随应实际应用的需要。丁二烯用苯乙烯共聚来改进它的抗张强度,用丙烯腈的共聚来改进它的耐油性,这是大家所熟悉的,再如:(1)聚苯乙烯的软化点在80°左右。 展开更多
关键词 共聚合反应 配料比 克分子分数 相对活度 单体 游离基 极性 摩尔分数 自由基 交替共聚物 竞聚率
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部