检索结果-南通市图书馆

Doebner condensation in ionic liquids [Bmim]BF_4 and [Bpy]BF_4 to synthesize α,β-unsaturated carboxylic acid

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2009年第3期20卷 279-282页

作者： Dong jiang yuan yuan Wang Yan Nan Xu Li Yi Dai Shanghai Key Laboratory of Green Chemistry and Chemical Processes Department of Chemistry East China Normal University Shanghai 200062 China

Ionic liquids [Bmim]BF4 and [Bpy]BF4 were employed as environmentally benign media in Doebner condensation to synthesize α, β-unsaturated carboxylic acid. The good results showed that [Bmim]BF4 and [Bpy]BF4 were efficient media for Doebner condensation, which could be recycled easily. The highest yields could reach 93% and 90% in [Bmim]BF4 and [Bpy]BF4, respectively.

关键词： Ionic liquid Doebner condensation α, β-Unsaturated carboxylic acid Decarboxylation

Increased Arterial Stiffness in Subjects with Pre-diabetes among Middle Aged Population in Beijing,China

在线全文

学校读者我要写书评

暂无评论

Biomedical and Environmental Sciences 2013年第9期26卷 717-725页

作者： SHEN Li ZHANG Yan Ge LIU Min WU Liu Xin QIANG Dong Chang SUN Xue Lei LIU Lin jiang yuan yuan Department of Epidemiology and Biostatistics School of Public Health Peking University Health Science Center Institute of Aviation Medicine AF

Objective To investigate the relationship between arterial stiffness and pre-diabetes when assessed by the new glycosylated hemoglobin Ale （HbAlc） 5.7%-6.4% criterion or by impaired fasting glucose in middle aged Chinese. Methods 1122 adults aged 55 years or younger in the health examination centers for physical check-ups were enrolled in the two large-sized Tertiary Comprehensive Hospitals in Beijing from June 2011 to June 2012 after excluding those who previously had been diagnosed or treated as diabetes or cardiovascular disease. Subjects with a diagnosis of pre-diabetes according to impaired fasting glucose （IFG）（fasting plasma glucose （FPG） levels at 5.6-6.9 mmol/L）, HbA^c levels at 5.7%-6.4%, or both, were classified into four groups for observation：（1） Normoglycaemia （HbA^c〈5.7% and FPG 〈5.6 mmol/L）; （2） IFG alone （FPG levels at 5.6-6.9 mmol/L and HbA1c〈5.7% ）; （3） HbAI~ 5.7%-6.4% alone （HbA^c levels at 5.7%-6.4% and FPG 〈5.6 mmol/L）; and （4） both HbA1c 5.7%-6.4% and IFG （l-lbA1~ levels at 5.7%-6.4% and FPG levels at 5.6-6.9 mmol/L）. All subjects were measured for weight, height, waist circumference, blood pressure, fasting plasma glucose, HbA1c, lipid profile and brachial-ankle pulse wave velocity （baPWV）. Results The mean values of baPWV were 1282±8, 1311±10, 1398±30, and 1418_±27 cm/s （Mean_±SE） in Normoglycaemia, HbA~ 5.7%-6.4% alone, IFG alone and the both HbAlc 5.7%-6.4% and IFG groups, respectively. After adjusting for age, gender, blood pressure, BMI and triglyceride, baPWV was significantly higher in subjects with both HbAlc5.7%-6.4% and iFG compared among the subjects with Normoglycaemia （1350±14 vs. 1301±6 cm/s, P=0.002） and HbA1c 5.7%-6.4% alone （1350±14 vs. 1309±8 cm/s, P=0.013）.Conclusion Subjects with pre-diabetes exhibited a greater arterial stiffness.

关键词： Pre-diabetes Vascular stiffness Arterial stiffness

The alcoholysis of acetonitrile prompted by Brфnsted acidic ionic liquid [HSO_3-pmim]HSO_4

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2008年第8期19卷 889-892页

作者： Dong jiang yuan yuan Wang Ming Tu Li Yi Dai Shanghai Key Laboratory of Green Chemistry and Chemical Processes Department of Chemistry East China Normal University Shanghai 200062 China

BrФnsted acidic ionic liquids based on imidazolium cation were employed as a series of environmentally benign catalysts and mediums in the alcoholysis of acetonitrile to synthesize ester. The results showed that BrФnsted acidic ionic liquid [HSO3- pmim]HSO4 was an efficient catalyst and medium for the alcoholysis of acetonitrile which could be recycled easily without obvious decline in catalytic activity, the highest yield could reach 85%.

关键词： BrФnsted acidic ionic liquid Alcoholysis Ester

The History of the Former Han Dynasty:A Critical Translation with Annotations Translated by Homer Hasenpflug Dubs

在线全文

学校读者我要写书评

暂无评论

Journal of Literature and Art Studies 2018年第7期8卷 1051-1057页

作者： jiang yuan-yuan jiangsu University JiangsuChina

Translation is an important medium of cultural *** is not a mere transfer of two languages,but the interaction of two *** misreading,which results from cultural discrepancy and translator’s subjectivity,truly reflects where the blockade and conflict in the cultural communication *** misreading is an objective phenomenon that exists in the entire process of *** paper intends to make a comprehensive analysis and discussion on The History of the Former Han Dynasty:a Critical Translation with Annotations translated by Homer Hasenpflug *** for the reasons of cultural misreading,this paper divides them into three types—language,thinking habit,traditional *** is to be hoped that this paper will draw more attention from the translation circle to the phenomena,and make contribution to the development of literary translation.

关键词： The History of the Former Han Dynasty a critical translation with annotations translation cultural misreading

Predicted lower limit of normal reduces misclassification risk of airflow limitation in asymptomatic elderly never-smokers

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Medical Journal 2013年第18期126卷 3486-3492页

作者： WANG Yang XIAO Wei MA De-dong jiang yuan-yuan Department of Respiratory Medicine Qilu Hospital Shandong University Jinan Shandong 250012 China

Background It remains controversial what better defines abnormal lung function at the extremes of age. This study aimed to establish new spirometric reference equations for residents in Jinan and compare the most accepted two spirometric definitions of chronic obstructive pulmonary disease （COPD）--a fixed post-bronchodilator ratio of forced expiratory volume in one second to forced vital capacity （FEVJFVC） below 70% vs. FEV1/FVC 〈lower limit of normal （LLN）-in an elderly population （age 〉60 years）. Methods Among 10 002 cases, only never-smokers who had no respiratory symptoms or diagnoses of cardio- pulmonary diseases and whose lung function measurements strictly followed the American Thoracic Society guidelines, were included in the statistical analysis. For each gender, prediction equations of FEV1, FVC, FEV1/FVC and corresponding LLN values were developed using multiple regression models. Results In this cross-sectional study, spirometric reference values were statistically derived from a sample of 1328 healthy never-smokers （672 males, 656 females）, age 56-84 years. As expected, age and height were the main predictors for all lung function parameters. Using the two spirometric definitions, the number of pulmonary function test results interpreted as obstructed varied markedly in the elderly population for both genders （males： X2=19.59, P 〈0.01; females： X2=5.67, P=0.017）. Conclusions The Global Initiative for Chronic Obstructive Lung Disease （GOLD） criterion probably leads to over- diagnosis in asymptomatic elderly never-smokers. Our study suggests that the predicted LLN values will reduce the misclassification risk instead. However, cohort studies are urgently needed for clinical validation.

关键词： pulmonary disease chronic obstructive spirometry FEV/FVC lower limit of normal

在线全文

学校读者我要写书评

暂无评论

基于路标点追踪的差速驱动机器人运动规划

控制与决策 2023年第9期38卷 2529-2536页

作者：刘延彬姜媛媛安徽理工大学力学与光电物理学院安徽淮南232001 安徽理工大学电气与信息工程学院安徽淮南232001

首先,针对三角网格路径规划方法采用D-P算法提取路标点时,其最大阈值不易确定等问题,提出基于碰撞检测的抽取路标点方法.同时采用Pure Pursuit算法跟踪路标点,对差速驱动机器人进行运动规划;然后,通过实验对比分析表明,在提取路标点时,... 详细信息

首先,针对三角网格路径规划方法采用D-P算法提取路标点时,其最大阈值不易确定等问题,提出基于碰撞检测的抽取路标点方法.同时采用Pure Pursuit算法跟踪路标点,对差速驱动机器人进行运动规划;然后,通过实验对比分析表明,在提取路标点时,与D-P算法相比,碰撞检测方法更加优越;最后,通过差速驱动机器人的运动规划实验表明:Pure Pursuit算法追踪路标点方法规划的运动轨迹为一条光滑曲线,能够有效地避开地图上的障碍物;机器人角速度和线速度均为光滑函数,变化平缓,在路标点附近出现较小波动,波动范围均在允许值内;运动规划时间为0.049 s,完全能够满足实际需求.研究结果表明,基于路标点追踪的移动机器人运动规划是一种简单有效的运动规划方法.

关键词：运动规划三角网格碰撞检测路标点路标点追踪

在线全文

学校读者我要写书评

暂无评论

超超临界机组无省煤器改造及优化

湖南大学学报（自然科学版） 2010年第12期37卷 45-48页

作者：姜媛媛周少祥徐鸿华北电力大学能源与工程学院北京102206

以一台1 000 MW超超临界机组为研究对象,将锅炉、汽轮机及发电厂热力系统作为一个整体,针对超超临界机组的特性,对其锅炉进行无省煤器改造,并相应地通过增加一级高压加热器来替代省煤器的给水加热的作用.改造后的机组流量发生改变,锅炉... 详细信息

以一台1 000 MW超超临界机组为研究对象,将锅炉、汽轮机及发电厂热力系统作为一个整体,针对超超临界机组的特性,对其锅炉进行无省煤器改造,并相应地通过增加一级高压加热器来替代省煤器的给水加热的作用.改造后的机组流量发生改变,锅炉内的工质在各个受热面内的吸热量也发生了变化;最后对回热系统进行优化.研究结果表明:改造后的锅炉效率基本保持不变,锅炉的效率由54.0%增加到了54.4%,全厂供电标准煤耗由304 g/kWh降低至302.9 g/kWh.

关键词：省煤器空气预热器火用损失

维普期刊数据库博看期刊

在线全文

学校读者我要写书评

暂无评论

基于不完全合同视角的高校教职制度改革研究

财经问题研究 2010年第1期 19-26页

作者：蒋媛媛东北财经大学劳动就业与人力资本开发研究中心辽宁大连116025

本文关注高校组织内部的合同特征,分析了高校组织内部的委托代理关系,提出由于高校教师行动与结果间关系的不确定性、科研教学成果量化和质量确认困难、多种工作任务的加总、教师目标的多重性、科研与教学的团队合作等问题,都会造成高... 详细信息

本文关注高校组织内部的合同特征,分析了高校组织内部的委托代理关系,提出由于高校教师行动与结果间关系的不确定性、科研教学成果量化和质量确认困难、多种工作任务的加总、教师目标的多重性、科研与教学的团队合作等问题,都会造成高校内部合同关系的不完备。依托于不完全合同理论框架,越是不完全的合同,就越应采取低强度的激励机制。在高校组织内部,相对于晋升制和聘任制,西方终身教职制度是一种弱激励的制度安排,因此,可以将终身教职制度作为未来高校教职制度改革的方向。

关键词：合同理论不完全合同激励强度终身教职制度

在线全文

学校读者我要写书评

暂无评论

营销双元性、吸收能力与企业营销绩效

贵州财经大学学报 2021年第2期 51-61页

作者：蒋园园西北政法大学商学院陕西西安710122

基于资源编排理论,高水平的营销开发与营销探索并不一定能够给企业带来更高的营销绩效。有鉴于此,本研究将营销双元性界定为营销开发与营销探索的平衡,同时在营销活动中进行开发与探索,并检验企业吸收能力对营销双元性的销售增长效应的... 详细信息

基于资源编排理论,高水平的营销开发与营销探索并不一定能够给企业带来更高的营销绩效。有鉴于此,本研究将营销双元性界定为营销开发与营销探索的平衡,同时在营销活动中进行开发与探索,并检验企业吸收能力对营销双元性的销售增长效应的调节作用。对广东省227家中小外向型民营企业进行问卷调查,并结合二手财务数据进行实证研究,结果表明:(1)营销双元性对企业销售增长的影响呈向上的凹形曲线;(2)高水平营销开发的企业中,营销双元性对销售增长的二次效应更强,即营销双元性对销售增长具有积极影响;(3)营销开发与营销探索通过营销双元性间接对企业销售增长产生影响。

关键词：营销双元性吸收能力营销绩效营销开发营销探索