检索结果-南通市图书馆

Chinese Journal of Chemical Engineering 2018年第6期26卷 1285-1291页

作者： Zhenhao Xi Tian Liu Wei Si Fenglei Bi zhimei xu Ling Zhao State Key Laboratory of Chemical Engineering East China University of Science and Technology

The concentration of acetaldehyde(AA) is the main quality index of poly(ethylene terephthalate)(PET) used in food and drink packaging.A new method for AA removal has been developed by using supercritical carbon dioxide(sc CO2) during the solid-state polycondensation of *** influence factors of AA removal including the temperature,pressure,reaction time and the size of pre-polymer particles are systematically studied in this *** results indicate that it is a highly efficient way to obtain high molecular weight PET with relative low concentration of ***,the polymerization degree of PET could increase from 27.9 to 85.6 while the concentration of AA reduces from 0.229 × 10^(-6) to 0.055 × 10^(-6) under the optimal operation conditions of 230 °C,8 MPa and size of 0.30–0.45 *** performance tests show the increasing extent of PET crystallinity due to the fact that the plasticization of sc CO_2 is not obvious with extended reaction time,therefore the increasing crystallinity has no significant influence on AA *** observations reveal that the effects of sc CO_(2-) induced plasticization and swelling on PET increase significantly with the decrease of prepolymer size,and the surface of PET becomes more loose and porous in favor of the AA removal.

关键词： Supercritical CO2 Solid-state polycondensation Poly(ethylene terephthalate) Removal of acetaldehyde

Impacts of water conservancy and soil conservation measures on annual runoff in the Chaohe River Basin during 1961-2005

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2010年第6期20卷 947-960页

作者： LI Zijun LI Xiubin xu zhimei College of Population Resources and Environment Shandong Normal University Jinan 250014 China Institute of Geographic Sciences and Natural Resources Research CAS Beijing 100101 China

Taking the Chaohe River Basin above the Miyun Reservoir in North China as a study area, the characteristics and variation trends of annual runoff and annual precipitation during 1961-2005 were analyzed applying Mann-Kendall test method on the basis of the hydrologic data of the major hydrological station （Xiahui Station） located at the outlet of the drainage basin and the meteorological data of 17 rainfall stations. Human activities including water conservancy projects construction and water diversion as well as implementation of soil and water conservation from 1961 to 2005 were carefully studied using time series contrasting method. The referenced period （1961-1980） that influenced slightly by human activities and the compared period （1981-2005） that influenced significantly by water conservancy and soil conservation measures were identified according to the runoff variation process analysis and abrupt change points detection during 1961-2005 applying double accumulative curve method, mean shift t-test method and Mann-Kendall mutation test technique. Based on the establishment of a rainfall-runoff empirical statistical model, impacts and the runoff-reducing effects of water conservancy and soil conservation measures on runoff reduction were evaluated quantitatively. The major results could be summarized as follows：（1） The annual precipitation in the drainage basin tends to decrease while the runoff has declined markedly since the 1960s, the average annual runoff from 1991 to 2000 was only 90.9% in proportion to that from 1961 to 1970. （2） The annual runoff variations in the drainage basin are significantly related to human activities. （3） During 1981-1990, 1991-2000, 2001-2005 and 1981-2005, the average annual runoff reduction amounts were 1.15×10^8, 0.28×10^8, 1.10×10^8 and 0.79×10^8 m^3 respectively and the average annual runoff-reducing effects were 31.99%, 7.13%, 40.71% and 23.79% accordingly. Runoff-reducing effects by water conservancy and soil conservation

关键词： impacts water conservancy and soil conservation measures annual runoff rainfall-runoff empirical statistical model the Chaohe River Basin

A Study of the Structural Properties and Thermal Stability of Chitosanases EAG1 by Molecular Dynamics Simulations

在线全文

学校读者我要写书评

暂无评论

Journal of Biomedical Science and Engineering 2018年第11期11卷 320-326页

作者： Yueming Li Jianchun xu zhimei xu Qingdao Langyatai Group Co. Ltd. Qingdao China

Chitosanases EAG1, a classical glycoside hydrolase from Bacillus ehimensis, is relatively unstable with higher temperature. This shortcoming seriously restricts its industrial application. Therefore, it is crucial to clarify the theoretical basis of thermo stability and to produce enzymes with high activity and stability. Using the structural modeling and molecular dynamical simulation, residues Leu84, Gly113, Asp116, Ala207 and Leu286 were believed to be the key residues for structural stability. Then the predicted residue Leu84 was mutated to ALA. It was shown that the L84A mutation can improve the thermal stability of chitosanases EAG1. Together with previous studies, mutations of G113C, D116C, A207C and L286C forms two sulfur bonds can change the thermal stability of EAG1. The results suggest that the thermal stability of EAG1 could be engineered by site-directed mutagenesis on the conserved residues. This protocol could be employed for improving thermal stability of other chitosanases EAG1.

关键词： Chitosanases EAG1 Thermal Stability Structural Modeling Moleculrar Dynamical Simulation

Effect of Marine Bacillus BC-2 on the Health-Beneficial Ingredients of Flavor Liquor

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

Food and Nutrition Sciences 2019年第6期10卷 606-612页

作者： Yueming Li Jianchun xu zhimei xu Qingdao Langyatai Group Co. Ltd. Qingdao China

The main aroma component of Luzhou-flavor Liquor is ethyl caproate, which is combined with appropriate amount of ethyl butyrate, ethyl acetate, ethyl lactate and so on. By adding the marine bacillus BC-2 (Accession number: MK811408) to substrate sludge, the bacillus complex bacterial liquid (pit Mud Functional Bacterial liquid) has been modified. The complex bacterial liquid was used in the production of Luzhou-flavor Liquor and it dramatically promoted the content of health-beneficial ingredients in the new workshop. These results demonstrated that the marine bacillus BC-2 can effectively improve the quality and health benefit of Luzhou-flavor Liquor.

关键词： Luzhou-Flavor Liquor Marine Bacillus BC-2 Flavoring Components

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

芬兰中小学地理课程改革及启示

外国中小学教育 2009年第11期 57-61页

作者：徐志梅东北师范大学山东师范大学人口资源环境学院

芬兰是世界上少数几个比较重视地理教学的国家之一。近些年来,随着芬兰中小学地理课程的改革,芬兰地理教育取得了很大进步。本文探讨了芬兰地理课程改革背景,对芬兰中小学地理新课程结构进行描述分析,并对芬兰中小学地理新课程特点进行... 详细信息

芬兰是世界上少数几个比较重视地理教学的国家之一。近些年来,随着芬兰中小学地理课程的改革,芬兰地理教育取得了很大进步。本文探讨了芬兰地理课程改革背景,对芬兰中小学地理新课程结构进行描述分析,并对芬兰中小学地理新课程特点进行归纳,以期对我国地理新课程改革提供借鉴。

关键词：芬兰地理课程改革

C8芳烃在SKI-400-40催化剂上的临氢异构化反应动力学

在线全文

学校读者我要写书评

暂无评论

化学反应工程与工艺 2010年第1期26卷 58-63页

作者：田野许志美赵玲华东理工大学化学工程联合国家重点实验室上海200237

利用固定床积分反应实验装置,在反应温度为365～410℃、空速为4～128 h^(-1)、氢烃物质的量比为3.8、反应压力为1.1 MPa条件下,对C_8芳烃在SKI-400-40催化剂上的临氢异构化宏观反应动力学进行了研究。采用六组分拟一级异构化反应网络,... 详细信息

利用固定床积分反应实验装置,在反应温度为365～410℃、空速为4～128 h^(-1)、氢烃物质的量比为3.8、反应压力为1.1 MPa条件下,对C_8芳烃在SKI-400-40催化剂上的临氢异构化宏观反应动力学进行了研究。采用六组分拟一级异构化反应网络,建立了C_8芳烃临氢异构化的宏观反应动力学模型,模型计算值与实验值吻合良好。得到的反应速率常数表明,二甲苯和乙苯间的转化可通过两种方式,一是两者之间的直接转化,二是两者通过C_8N+P的桥接转化,其中第二种方式的贡献更大。

关键词：碳八芳烃临氢异构化动力学模型

基于情境类型学的初中地理学业水平考试试题情境研究

在线全文

学校读者我要写书评

暂无评论

地理教学 2024年第23期 24-27,55页

作者：赵洁徐志梅济南市莱芜区花园学校山东济南271100 山东师范大学地理与环境学院山东济南250358

地理试题情境是有效评价学生地理学业水平和核心素养的关键。本研究在情境类型学的基础上,从辨别参数、内容参数和装扮参数三个维度,对2021~2023年山东省24套初中地理学业水平考试试题情境进行量化分析。研究发现,该部分试题情境存在许... 详细信息

地理试题情境是有效评价学生地理学业水平和核心素养的关键。本研究在情境类型学的基础上,从辨别参数、内容参数和装扮参数三个维度,对2021~2023年山东省24套初中地理学业水平考试试题情境进行量化分析。研究发现,该部分试题情境存在许多优点,但也存在一些问题。试题情境创设可从以下方面进行优化:精选真实情境,聚焦学科育人价值;设置关联情境,遵循问题进阶路径;创新开放情境,关注高阶思维评价;精准呈现情境,保证试题情境有效;调节情境难度,构建合理梯度层级。

关键词：初中地理学业水平考试试题情境情境类型学

基于MP-PIC方法的冶金硅氢氯化流化床反应器模拟

在线全文

学校读者我要写书评

暂无评论

化工学报 2022年第10期73卷 4419-4428页

作者：吴诗鸣陈皓宁宗原许志美赵玲华东理工大学化学工程联合国家重点实验室上海200237

冶金硅氢氯化流化床是目前多晶硅生产工艺中实现四氯化硅(silicontetrachloride,STC)循环利用的关键反应器。基于MP-PIC方法建立了冶金硅氢氯化流化床反应器模型。模型中反应源项采用总包反应动力学进行计算。在网格以及计算颗粒包含的... 详细信息

冶金硅氢氯化流化床是目前多晶硅生产工艺中实现四氯化硅(silicontetrachloride,STC)循环利用的关键反应器。基于MP-PIC方法建立了冶金硅氢氯化流化床反应器模型。模型中反应源项采用总包反应动力学进行计算。在网格以及计算颗粒包含的真实颗粒数量无关性检验的基础上,对反应器内三氯氢硅(trichlorosilane,TCS)初始浓度进行了无关性检验。模型验证结果表明,模拟结果与实验值符合良好。反应器特征分析结果表明:TCS产率受化学平衡与气固两相流动因素共同控制;反应器操作压力对TCS产率的影响较小;提高进口H_(2)/STC摩尔比,可以提高TCS产率但会降低H_(2)的转化率。

关键词：多晶硅氢氯化流化床反应器计算流体力学 MP-PIC

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

棉籽油基聚氨酯弹性体的合成及性能

功能高分子学报 2020年第6期33卷 563-569页

作者：李佳许志美奚桢浩赵玲华东理工大学上海市多相结构材料化学工程重点实验室上海200237

生物基聚氨酯是高端生物材料领域的重要研究方向。采用臭氧化棉籽油基多元醇(OTO-polyols)和蓖麻油(CO)为原料,与异佛尔酮二异氰酸酯(IPDI)反应合成了一系列棉籽油基聚氨酯(TO-PU)弹性体。利用红外光谱(FT-IR)解析了聚氨酯弹性体的链结... 详细信息

生物基聚氨酯是高端生物材料领域的重要研究方向。采用臭氧化棉籽油基多元醇(OTO-polyols)和蓖麻油(CO)为原料,与异佛尔酮二异氰酸酯(IPDI)反应合成了一系列棉籽油基聚氨酯(TO-PU)弹性体。利用红外光谱(FT-IR)解析了聚氨酯弹性体的链结构,通过差示扫描量热仪、万能试验机和热重分析仪分别研究了材料的热行为、力学性能及热稳定性。结果表明:所合成的棉籽油基聚氨酯具有较低的玻璃化转变温度(−35~−28℃)和一定的结晶性能;通过调节软段棉籽油基多元醇与蓖麻油的质量比可以调控TO-PU的力学性能,其拉伸强度可超过2.50 MPa,断裂伸长率大于150%;棉籽油基聚氨酯的起始分解温度高于240℃,热稳定性良好。

关键词：棉籽油基多元醇聚氨酯拉伸强度热稳定性

在线全文

学校读者我要写书评

暂无评论

仲丁基苯液相氧化反应动力学

化工学报 2018年第11期69卷 4737-4745页

作者：董健张胜露孙伟振许志美赵玲化学工程联合国家重点实验室华东理工大学上海200237

非催化条件下仲丁基苯(SBB)液相氧化制备过氧化氢仲丁基苯(SBBHP)是生产苯酚和甲乙酮的关键步骤。基于烃类链式自由基反应机理,分别建立了氧充足和限氧条件下SBB氧化动力学模型,模型包含了反应物SBB、主产物SBBHP、副产物苯乙酮(ACP)、2... 详细信息

非催化条件下仲丁基苯(SBB)液相氧化制备过氧化氢仲丁基苯(SBBHP)是生产苯酚和甲乙酮的关键步骤。基于烃类链式自由基反应机理,分别建立了氧充足和限氧条件下SBB氧化动力学模型,模型包含了反应物SBB、主产物SBBHP、副产物苯乙酮(ACP)、2-苯基-2-丁醇(PBO)等。通过分别拟合不同条件下的实验数据(388~403K),得到了相应的基元反应速率常数和活化能。结果表明,由于空间位阻效应,主反应生成SBBHP的活化能大于异丙苯(IPB)生成过氧化氢异丙苯(CHP)的活化能。连续实验进一步验证了动力学模型的可靠性。相关研究结果可用于仲丁基苯液相氧化过程的设计和优化,并且基元反应相关结果有利于丰富对烷基芳烃氧化反应机理的认识。

关键词：仲丁基苯液相氧化动力学模型过氧化氢仲丁基苯