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Search Results: 1 - 10 of 4647 matches for " DUAN Zhengkang "
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Simultaneous determination of acetylacetone and acetone in the reaction mixture for producing acetylacetone by high performance liquid chromatography
高效液相色谱法同时测定乙酰丙酮反应液中的乙酰丙酮和丙酮

ZENG Hongyan,DUAN Zhengkang,LUO Aiwen,ZENG Zhiding,
曾红艳
,段正康,罗爱文,曾志丁

色谱 , 2010,
Abstract: 建立了一种同时检测乙烯酮-丙酮法制乙酰丙酮反应液中乙酰丙酮和丙酮的高效液相色谱法(HPLC)。采用Agilent Eclipse XDB-C18色谱柱,以四氢呋喃-水(15:85, v/v)溶液为流动相(用0.1 mol/L磷酸二氢钠缓冲盐调节pH为4.0~5.0),流速0.6 mL/min,紫外检测波长270 nm,采用外标法定量。在优化的条件下,乙酰丙酮和丙酮的线性范围分别为0.01~50.00 mg/L和0.01~30.00 mg/L,相关系数均为0.9999以上。使用HPLC测定乙酰丙酮和丙酮的含量,其相对标准偏差均小于1.0%,结果表明方法的重复性好;反应液中添加乙酰丙酮和丙酮的加标回收率均为99.00%~101.50%。与应用紫外分光光度法测定乙酰丙酮的结果相比,平均相对误差为1.48%。所建立的方法为用丙酮生产乙酰丙酮等类似混合体系中乙酰丙酮的定量分析提供了依据,同时为酮类化合物的测定提供了准确、便捷的方法。
Determination of hexane in the acid cluster of caprolactam by high performance liquid chromatography with indirect photometric detection
高效液相色谱-间接光度检测法测定己内酰胺酸团中的正己烷含量

LI Linan,DUAN Zhengkang,ZENG Hongyan,HE Yuping,CHEN Qiuyun,
李立南
,段正康,曾红艳,贺玉平,陈秋云

色谱 , 2011,
Abstract: An indirect photometric detection method for the determination of hexane in the acid cluster of caprolactam by high performance liquid chromatography was developed.Ultraviolet(UV) absorption background reagents were added in the mobile phase,and the hexane,non-absorption in ultraviolet region,was directly determined by a UV detector.The effects of the mobile phase composition,species and concentration of the background reagents etc.on the analyzed results were studied.The optimization of the separation was ...
Influence of the March 11, 2011 M w 9.0 Tohoku-oki earthquake on regional volcanic activities
Fan Wang,ZhengKang Shen,YanZhao Wang,Min Wang
Chinese Science Bulletin , 2011, DOI: 10.1007/s11434-011-4523-y
Abstract: Two days after the March 11, 2011, M w 9.0 Tohoku-oki earthquake, Shinmoedake volcano, located on the Japanese island of Honshu, erupted. Was this eruption triggered by the Tohoku-oki earthquake? Could Mount Fuji and Changbaishan volcanoes also be triggered to erupt? By calculating changes in the regional stress-strain field that resulted from the earthquake, we find that Mount Fuji, Shinmoedake and Changbaishan volcanoes are all located in regions of volumetric expansion. The volumetric expansions at a depth of 10 km are up to ~220 nano-strain, ~8 nano-strain, and ~14 nano-strain, respectively, for the three volcanoes. The strain changes inferred from GPS co-seismic displacements also suggest that these three volcanoes are located in regions with surface areal expansion. Considering that the expansional stress may cause the opening of magma channels, exsolution of CO2 gases stored in magma, and a series of positive feedback effects, the Tohoku-oki earthquake may result in an increase in the activity of these volcanoes. Attention should be paid to potential triggering of volcanic eruptions by stress changes induced by the Tohoku-oki earthquake.
EFFECTS OF TOTAL ISOFLAVONES OF RED CLOVER ON MALE BROILER GROWTH AND SERUM TESTOSTERONE CONCENTRATION
红三叶草总异黄酮对小公鸡生长及血清睾酮水平的影响

Wang Guojie,Han Zhengkang,
王国杰
,韩正康

动物学研究 , 1994,
Abstract: Total isoflavones extracted from red clover were supplemented in the diets (4.38 mg/kg feed) of male Redbro broilers (45-56 days of age, n=15). Body weight gain of treated male chickens increased by 5. 1%, feed conversion increased by 9.2%. Slaughter results showed that abdominal fat pad and ratio of abdominal fat pat to carcass weight decreased significantly, whereas comb weight, testis weight increased. The analysis of correlation coefficient between comb. testis and body weight, the observation of paraffin seetions of testis and the radioimmunoassay (RIA) of the serum testosterone levels indicated that the total isoflavons could elevate serum testosterone levels and promote the development of the reproductive organs of male broiler chickens.
Higher-Order Numeric Solutions for Nonlinear Systems Based on the Modified Decomposition Method  [PDF]
Junsheng Duan
Journal of Applied Mathematics and Physics (JAMP) , 2014, DOI: 10.4236/jamp.2014.21001
Abstract:

Higher-order numeric solutions for nonlinear differential equations based on the Rach-Adomian-Meyers modified decomposition method are designed in this work. The presented one-step numeric algorithm has a high efficiency due to the new, efficient algorithms of the Adomian polynomials, and it enables us to easily generate a higher-order numeric scheme such as a 10th-order scheme, while for the Runge-Kutta method, there is no general procedure to generate higher-order numeric solutions. Finally, the method is demonstrated by using the Duffing equation and the pendulum equation.

Fiscal Decentralization, Corruption and Urban-Rural Income Inequality: Evidence from China  [PDF]
Longlong Duan
Theoretical Economics Letters (TEL) , 2015, DOI: 10.4236/tel.2015.54056
Abstract: This paper follows fiscal federalism that a higher degree of fiscal decentralization is always associated with lower corruption and income inequality. There exists a stronger dynamic relationship among fiscal decentralization, corruption and income inequality in developing countries. Based on the panel dataset from 1999 to 2012, this research is focusing on China, showing that it does not exist a simple linear relationship among fiscal decentralization, corruption and urban-rural income inequality, instead, the relationship between fiscal decentralization and urban-rural income inequality is more in line with a specific “U” shape. While the effect of corruption on urban-rural income inequality, it can be gradually weakened as the reform of fiscal decentralization which expands the existed researches made by Mah (2013) and Lessmann (2010).
A Study of Fostering College English Students’ Awareness of Cultural Comparison in Chinese Classrooms  [PDF]
Libin Duan
Open Journal of Social Sciences (JSS) , 2016, DOI: 10.4236/jss.2016.45013
Abstract: The study examines the effectiveness of different culture-oriented approaches to foster college English students’ awareness of cultural comparison in Chinese classrooms. A survey about college students’ status quo in English learning indicates that they are poor in western cultural knowledge, especially lack cultural comparative sense and ability. Therefore, based on the second language acquisition theory and the constructivism theory, the study aims at exploring some effective culture-oriented approaches to develop Chinese college English students’ cross-cultural communication ability. After a term’s experimental teaching in the author’s two classes, and data collection and analysis, it is concluded that the following approaches are effective: duty report, various classroom activities, self-access study, hosting the online instruction, etc.
The Prolongation Structures for the System of the Reaction-Diffusion Type  [PDF]
Xiaojuan Duan
Journal of Applied Mathematics and Physics (JAMP) , 2017, DOI: 10.4236/jamp.2017.51010
Abstract: Equations of the reaction-diffusion type are very well known and have been extensively studied in many research areas. In this paper, the prolongation structures for the system of the reaction-diffusion type are investigated from theory of coverings. The realizations and the classifications of the one-dimensional coverings of the system are researched. And the corresponding conservation law of the one-dimensional Abelian coverings is concluded, which is closely connected with the symmetry of the system by Noether theorem.
Analysis on the Application of PPP Mode in Hangzhou City Management
—Take the Infrastructure Construction as an Example
 [PDF]

Zhenpeng Duan
Open Journal of Social Sciences (JSS) , 2017, DOI: 10.4236/jss.2017.512002
Abstract:
Facing the phenomenon that the increasingly serious shortage of infrastructure causes urban problems, the government will introduce PPP mode to the field of city management, and it achieves good economic and social benefits to promote the sustainable development of PPP mode in city management. Based on the survey of Hangzhou Metro Line 1 and the travelling citizens and the analysis of SPSS data, we can know that the operation management of the later stage is the main reason that affects the sustainable development of PPP mode. Based on this, the paper proposes that in the operation management of the later stage, we should strive to improve the relevant supporting facilities and the quality of services, so as to enhance the public’s satisfaction to the project, thereby promoting the sustainable development of PPP mode in city management.
The Redistribution Effect of Social Security System under Birth Control  [PDF]
Xueqin Duan
Open Journal of Social Sciences (JSS) , 2018, DOI: 10.4236/jss.2018.63014
Abstract:
This paper establishes an OLG model to analyze the long-term effect of social security on inequality under birth control. We study the effect of population policy and social security on fertility and education of families with different income. Then this effect determines the evolution of inequality. The analyses suggest that the effect of social security on inequality in the next generation is depended on population policy and the differentiation of family care.
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