化学

Unfortunately, it has been shownthat these methods are not suitable to study about chemical bonds due to not involvingchemical bonds. In order to consider chemical bonds obviously, we have proposed an atom-bondelectronegativity equalization model on the basis of density-functionaltheory and electronegativity equalization principle. The main contents of our atom-bond electronegativity equalization model contain:(1)Considering the fact that there are varies of chemical bonds in molecules andpartitioning the molecular electron density as summations of atomic electron densitiesand chemical bond's electron densities, we obtained the basic equations of atom-bondelectronegativity equalization model: the expression of the total energy 〓, theexpression of the atom electronegativity 〓 and the expression of the bondelectronegativity 〓.

为了明确地考虑和处理分子中存在的化学键，以便能够更好地描述体系中的电荷分布进而准确地描述分子体系中的有关物理化学性质，尤其是与化学键有关的物理化学性质，我们在密度泛函理论和电负性均衡原理基础上提出了原子-键电负性均衡模型，原子-键电负性均衡模型的主要内容是：(1)考虑到分子体系中存在各种化学键这个事实，将分子空间看成是由原子区和化学键区组成的，将分子的单电子密度表达成为分子中各组成原子的单电子密度和各化学键的单电子密度的加和，从而得到了原子-键电负性均衡模型的基本方程：分子体系总能量〓和分子中原子电负性〓和化学键电负性〓表达式。

Chemical symbol is basic feature of chemistry and the tool of chemistry-studying and scientific thinking.

化学符号是化学学科重要的特征之一，是学生学习化学和科学思维的工具，化学符号必然在学生化学问题解决中扮演重要角色。

Research in the domain of the fundamental conception of chemistry in high school is of great importance to the implementation of chemistry curriculum criterion , to the reformation of chemistry teaching in class education, to the promotion of students' development, and to the improvement of the effect of class.

研究中学化学基本观念既是新时代背景下，化学教育目的转型的需要，又是贯彻落实化学课程标准的需要，既是化学新课程改革的必然要求，又是化学课堂教学改革的需要，还是促进学生发展和提高课堂成效性的需要。

It is necessary to show the development and new knowledges of Organic Chemistry, the function of chemistry in human society and bioscience. The column of Related essay provides such materials so as to help students abandon out-of-date knowledges and offer them modern ones which advance with time.

在有机化学课程中适当反映化学发展的动态、与化学前沿科学相关的化学知识、化学科学在人类社会发展及生命科学中的作用等内容，这不仅是摒弃化学旧知识、呈现化学新知识，使新的化学课程内容富有时代气息的需要，也是体现科学大综合、学科大交叉的科学发展趋势的需要。

Beginning with the investigation of the mathematics studying of the freshmen the author de signed a questionnaire, and found that the adaptability level of the freshmen's chemistry learning is not high enough, and that the majority of freshmen are unadaptable to their chemistry teacher's teaching method in universities.

本文从非化学专业大学新生学习化学的实际情况调查入手，通过自编的调查问卷，深入分析发现大学新生化学学习的总体适应性水平不高，在面对突如其来的学习内容差异和环境的转换，学生很难体会到化学教学的魅力，难以形成专业自豪感和学习的兴趣，普遍不适应大学化学教师的教学方式。

Through one year continuous observation the water chemistry,the seasonal,annual changes of water chemical composition and hydrochemistry type were mastered.which has important scientific significance on Chemical composition of groundwater and river water sources and changes regulation,as well as chemical characteristics of water,This research has practical significance on thescientificly and rationally development and utilization of local water resources and tourism reseo...urces and environmental protection.

通过对该地区水化学成分连续的观测。可以查明翠华山和少陵塬地区河水与泉水化学成分的季节变化、年变化及其水化学类型等，这对揭示该区地下水与河水化学成分来源与变化规律以及水化学特征有重要科学意义。

Environmental chemistry is an intersectant subject by environmental science and chemistry. Its core problem is to study the chemical transformation and effect of chemical pollutant in environment. The research object of environmental chemistry is a complicated system with many components and mediums. The content of chemical pollutants researched by environmental chemistry is very low. These chemical pollutants distribute extensively, move and transform quickly, and have obvious dynamic change under different space-time conditions.

环境化学是环境科学与化学的交叉学科，它的核心问题是研究化学污染物在环境中化学转化和效应；环境化学研究的对象是一个多组分、多介质的复杂体系；环境化学所研究的化学污染物在环境中的含量很低；化学污染物分布广泛，迁移转化速度较快，在不同时空条件下有明显的动态变化。

From the experiment discovered for the first time the dimethyl ether may substitute CO to take the chain-carrying agent of the peroxy free radical chemistry amplifier system, and optimized the CH_3OCH_3-NO-HO_2 chemistry amplifying system determination condition, the CH_3OCH_3 best density is 1.876 ppmv, the NO best density is 1.3ppmv, and obtained this method chain length CL=124, 5 parallel determinations densities of HO_2 are the 44.0pptv, the relatively standard deviation is smaller than 4%; Although chemistry box model computed result indicated the dimethyl ether, the ethene, the propene and the ethanol all can take the chain-carrying agent of the peroxy free radical chemistry amplifier system, and their simulation chain length all grows up compared to the CO-NO-HO_2 chemistry amplifying systems, but experiments proved the ethene, the propene and the ethanol have not suit the chain-carrying agents.

首次从实验上发现二甲醚可以替代CO作为过氧自由基化学放大系统的链传递试剂，并优化了CH_3OCH_3-NO-HO_2化学放大系统的测定条件，CH_3OCH_3的最佳浓度是1876ppmv，NO的最佳浓度为1.3ppmv，并得到了这一方法的链反应长度(CL=124)，5次平行测定浓度为44.0pptv的HO_2自由基，相对标准偏差＜4％；虽然化学盒子模式计算结果表明二甲醚、乙烯、丙烯和乙醇都能作为过氧自由基化学放大系统的链传递试剂，并且它们的模拟链长都比CO-NO-HO_2化学放大体系的链长大，但是实验证明乙烯、丙烯和乙醇不适合作为过氧自由基化学放大系统的链传递试剂。

The mullite is M60 mullite containing Al2O3 not less than 60 wt%, the cordierite contains Al2O3 33-35 wt% and MgO 13-15 wt%, the micro silica powder contains SiO2 not less than 92 wt%, the micro active alumina powder contains Al2O3 more than 98 wt%, the high alumina cement contains Al2O3 not less than 46 wt%, CaO not more than 40 wt% and SiO2 not more than 10 wt%.

其中，所述的莫来石为M60莫来石，其化学成分为：Al 2 O 3 ≥60％；堇青石化学成分为：Al 2 O 3 33～35％，MgO 13～15％；硅微粉化学成分为：SiO 2 ≥92％；活性氧化铝微粉化学成分为：Al 2 O 3 ＞98％；高铝水泥化学成分为：Al 2 O 3 ≥46％，CaO≤40％，SiO 2 ≤10％。

The market with "chemical dangerous goods business license,""flammable and explosive chemical fire safety permits", flammable and explosive chemicals and dangerous goods storage of highly toxic chemicals for dangerous goods for storage, I Admission for the broad market may be operating companies charge d'affaires of dangerous goods business license and registered the bonded area companies.

市场具备《化学危险品经营许可证》，《易燃易爆化学物品消防安全许可证》、易燃易爆化学危险品仓储资格和剧毒化学危险品仓储资格，我市场可为广大入场经营性公司代办化学危险品经营许可证，以及注册保税区公司。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。