检索结果-南通市图书馆

Permeable Steel and Its Application in Plastic-injection Mould

Chinese Journal of Mechanical Engineering 2010年第3期23卷 312-316页

作者： ZHOU Zhaoyao CAO Wenjiong WU zhengqiang YU Minqiang li Yuanyuan School of Mechanical and Automotive Engineering South China University of Technology Guangzhou 510640 China

The gas in plastics mould has great influence on performance, appearance and lifespan of the injection molded parts. Venting channel and its appendix system should be used for gas exhausting in general. However, the dependence on the venting system complicates the mould design. Furthermore in certain condition, it is difficult to integrate the venting system into the mould. Currently a kind of mold material which has gas permeability has been developed in abroad, but the applications of this mold material were restricted by its higher cost and smaller size. In this research, a porous material which was made by powder metallurgy was applied to plastic mould to replace the venting system. Permeability of the steel with different secondary processing was tested and compared with a special apparatus. The metallographic samples of the steel with different secondary processing were prepared and investigated. Finally an actual injection set was established to investigate the applications of permeable steel. The metallographies indicate that the micro-holes inside permeable steel were interconnected. Moulds made of permeable steel exhibit good permeability in the plastic-injection experiments and gas generated in the mould cavity was smoothly exhausted. The melted plastic did not penetrate into the mould or block in the micro-holes. After several times of plastic-injection experiments, the mould still retained good permeability. The strength of this permeable steel is between 200–250 MPa and suitable for industrial applications. The venting systems simplified by permeable steel in plastic-injection have simple structures, which can be applied into any place that requires gas exhausting.

关键词： powder metallurgy permeable steel plastic-injection mould venting system

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Unique fluorescence properties of a self-assembling bis-pyrene molecule

引用

Chinese Chemical Letters 2018年第11期29卷 1645-1647页

作者： Zhaozhong li Yang li Dong Wang Qing Cui zhengqiang li Lei Wang Huai Yang Department of Materials Physics and Chemistry School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China National Center for Nanoscience and Technology (NCNST) Beijing 100190 China Department of Materials Science and Engineering College of Engineering Peking University Beijing 100871 China

A self-assembling bis-pyrene （BP） molecule with π-π interactions was designed and synthesized. In condensed state, the BP self-assembled into highly-ordered mesophase at room temperature, which was characterized by using differential scanning calorimetry （DSC）, polarized optical microscope （POM）, and 1 D wide angle X-ray diffraction （WAXD） techniques. In solution, the BP self-assembled into nanoflbers in the mixed dichloromethane and hexane （1：1 volume ratio） solvent. Interestingly, the BP was not fluorescent when dissolved in dichloromethane solution. However, the self-assembled nanostructures of BP in the mixed solvent showed high intensity of green fluorescence. The advantages of self-assembly and fluorescence feature exhibited that BP could be promising fluorescence nanoprobes or nanosensors for various applications.

关键词： Bis-pyrene Fluorescence Self-assembly Mesophase π-π Interaction

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A satellite-derived,ground-measurement-independent monthly PM_(2.5)mass concentration dataset over China during 2000-2015

引用

Big Earth Data 2022年第4期6卷 633-649页

作者： Ying Zhang zhengqiang li Yuanyuan Wei Zongren Peng State Environmental Protection Key Laboratory of Satellite Remote Sensing Aerospace Information Research InstituteChinese Academy of SciencesBeijingChina

Following the accelerated development of urbanization and industrialization,atmospheric particulate matter has become a significant threat to public health *** health studies usually use the mass concentration of fine particles(PM_(2.5))as a base data to predict the health risks of particulate ***,PM_(2.5)data from ground monitoring stations in China has not been provided until January 2013 by the Ministry of Environmental Protection of ***,an alternative dataset of PM_(2.5)spatiotemporal distributions extending to years earlier than 2013 is urgently needed,which is of great significance to atmospheric environment assessment and pollution prevention and *** aerosol products by the moderate-resolution imaging spectroradiometer(MODIS)have been released since 2000,which provides the possibility to reconstruct historical PM_(2.5).However,most current methods do not have the ability to estimate PM_(2.5)mass concentration independently of ground *** PM_(2.5)mass concentration data set produced by PM_(2.5)remote sensing(PMRS)model based on physical processes does not depend on the ground observations,and also is not affected by the uncertainty of model emission sources or the completeness of chemical reaction *** ensure that the point-by-point validation for PM_(2.5)mass concentration data is more convincing,and the dataset can also be further used for model assimilation and artificial intelligence training to improve their *** this study,we calculate the monthly PM_(2.5)mass concentration near the ground over land of China using aerosol inversion products(aerosol optical depth and fine-mode fraction)of MODIS and meteorological data(boundary layer height&relative humidity)provided by the Modern-Era Retrospective Analysis for Research and Applications Version 2(MERRA-2)data *** results show that,in China,6 pollution centers mainly concentrated in the central and eastern regions.T

关键词： PM_(2.5) data set satellitederived China monthly

来源：

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

Theoretical Investigation on Binding Process of Allophanate to AUophanate Hydrolase

引用

Chemical Research in Chinese Universities 2015年第6期31卷 1023-1028页

作者： ZHANG Zidong ZHANG Jilong ZHENG Qingchuan KONG Chuipeng li zhengqiang ZHANG Hongxing MA Jianzhang College of Wildlife Resource Northeast Forestry University Harbin 150040 P. R. China International Joint Research Laboratory of Nano-miero Architecture Chemistry Institute of Theoretical Chemistry Jilin University Changchun 130021 P. R. China Key Laboratory for Molecular Enzymology and Engineering Ministry of Education Jilin University Changchun 130012 P. R. China

t Several molecular simulation methods were integrated to investigate the detailed binding process of allo- phanate to allophanate hydrolase and predict their stable complex structure. The optimal enzyme-substrate complex conformation demonstrates that along with Arg307 and Tyr299, Gly124 is also one of the key anchor residues in the stable complex. The energetic calculation suggests the existence of an intermediate state in the enzyme-substrate binding process. The further atomic-level investigation illuminates that Tyr299, Arg307 and Ser172 can stabilize the substrate in the intermediate state. By this token, the residues Arg307 and Tyr299 function in both binding process and getting stable state.

关键词： Allophanate hydrolase Molecular dynamics simulation Substrate binding Free energy Intermediate state

来源：

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

Advances in methane emissions from agricultural sources:Part *** and mitigation

引用

Journal of Environmental Sciences 2024年第6期140卷 279-291页

作者： Xiaokun Wu Ying Zhang Yinghui Han Yagang Zhang Yuhang Zhang Xiaodan Cheng Pei Zhong Xue Yuan Yuanxun Zhang zhengqiang li State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China Hebei Key Laboratory of Physics and Energy Technology North China Electric Power UniversityBaoding 071003China College of Resources and Environment University of Chinese Academy of SciencesBeijing 101408China Interdisciplinary Mathematics Institute University of South CarolinaColumbiaSC 29208United States Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China

Methane is one of the major greenhouse gases(GHGs)and agriculture is recognized as its primary *** accounting is a prerequisite for developing effective agriculture mitigation *** this review,methane accounting methods and research status for various agricultural emission source including rice fields,animal enteric fermentation and livestock and poultry manure management were overview,and the influencing factors of each emission source were analyzed and *** the same time,it analyzes the different research efforts involving agricultural methane accounting and makes recommendations based on the actual ***,mitigation strategies based on accounting results and actual situation are *** review aims to provide basic data and reference for agriculture-oriented countries and regions to actively participate in climate action and carry out effective methane emission mitigation.

关键词： Methane emission Agricultural sources Accounting methodology Mitigation Emission influencing factors

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Hot-melt extrusion promotes dissolution,extends“spring-parachute”process and inhibits crystallization in supersaturating microparticle systems

引用

Particuology 2023年第7期78卷 35-48页

作者： Yanfei Zhang Huifeng Zhang Huan Yu Yinghui Ma Chengyi Hao Xiaoying lin Yong Zhang zhengqiang li Xianrong Qi Jia Zeng Nianqiu Shi School of Pharmacy jilin Medical University Jilin132013jilin ProvinceChina Collge of life Science Jilin UniversityChangchun130012jilin ProvinceChina Department of Pharmaceutics School of Pharmaceutical SciencePeking UniversityBeijing100191China College of Pharmaceutical Sciences Yanbian UniversityYanji133002jilin ProvinceChina

Despite the potential advantages of amorphism-induced supersaturation,the merit of new amorphiza-tion formation methods on the properties of the amorphous drug including the stability of the amor-phous state,dissolution/solubility,supersaturation,and"spring-parachute"process is still poorly understood,particularly for certain amorphous supersaturating drug delivery systems(aSDDS).The present work aimed to explore the detailed merit of current attractive amorphization manufacturing methods(i.g.,hot-melt extrusion(HME)technique)on the property improvement of aSDDS in form of amorphous solid dispersion microparticles by employing a model Bcs II drug nitrendipine and a polyvinylpyrrolidone-based model polymer *** asDDS systems were developed by various methods,and their physicochemical properties were characterized by SEM,PXRD and ***-triggered amorphization induced superior supersaturation by the observation of the highest dissolution and *** induced the optimal supersaturation duration by the observed greatest extension of"spring-parachute"process(e.g,maximum AUCspring-parachute).HME technique is comparable with other techniques for the stabilization of amorphous state during *** aSDDS systems by HME and other methods showed improved long-term stability of the amorphous state in comparison to the pure amorphous *** transformation infrared spectroscopy,Noyes-Whitney equation,nucleation theory and Gibbs free energy of transfer(△G)were used to analyze the underlying ***-lecular mechanism studies indicated that HME caused a stronger crystallization inhibition effect in the asDDS systems than other methods,but molecular interaction is not a dominant mechanism for property enhancement caused by *** the mechanism associated with the polymer itself(PVPVA64),it could inhibit the drug recrystallization,solubilize the drug spontaneously and cause the improved molecular interactions in all aSDDS *** study provided

关键词： Hot-melt extrusion-triggered amorphization Extensionof"spring-parachute"process Promotion of dissolution/solubility Inhibition of crystallization from a supersaturated state Amorphism-based supersaturating drug microparticle systems

来源：

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

Advances in Atmospheric Radiation:Theories,Models,and Their ***Ⅱ:Radiative Transfer Models and Related Applications

引用

Journal of Meteorological Research 2024年第2期38卷 183-208页

作者： Hua ZHANG Feng ZHANG Lei liU Yuzhi liU Husi LETU Yuanjian YANG zhengqiang li Kun WU Shuai HU Ming li Tie DAI Fei WANG Zhili WANG Yuxiang liNG Yining SHI Chao liU State Key Laboratory of Severe Weather and Institute of Climate System Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081 Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210044 Department of Atmospheric and Oceanic Sciences&Institute of Atmospheric Sciences Fudan UniversityShanghai 200438 College of Meteorology and Oceanography National University of Defense TechnologyChangsha 410073 College of Atmospheric Sciences Lanzhou UniversityLanzhou 730000 State Key Laboratory of Remote Sensing Science Aerospace Information Research InstituteChinese Academy of SciencesBeijing 100101 School of Atmospheric Physics Nanjing University of Information Science&TechnologyNanjing 210044 School of Atmospheric Sciences Nanjing University of Information Science&TechnologyNanjing 210044 Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029 CMA Earth System Modeling and Prediction Centre China Meteorological Administration(CMA)Beijing 100081

The subject of“atmospheric radiation”includes not only fundamental theories on atmospheric gaseous absorption and the scattering and radiative transfer of particles(molecules,cloud,and aerosols),but also their applications in weather,climate,and atmospheric remote sensing,and is an essential part of the atmospheric *** review includes two parts(Part I and PartⅡ);following the first part on gaseous absorption and particle scattering,this part(PartⅡ)reports the progress that has been made in radiative transfer theories,models,and their common applications,focusing particularly on the contributions from Chinese *** recent achievements on radiative transfer models and methods developed for weather and climate studies and for atmospheric remote sensing are firstly ***,the associated applications,such as surface radiation estimation,satellite remote sensing algorithms,radiative parameterization for climate models,and radiative-forcing related climate change studies are summarized,which further reveals the importance of radiative transfer theories and models.

关键词： atmospheric radiation radiative transfer remote sensing radiative forcing climate change

来源：

维普期刊数据库

同方期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Baosteel's No.8 air separation unit and the practice of its system commissioning

引用

Baosteel Technical Research 2009年第3期3卷 23-26页

作者： ZHOU Chenhao CAI Lemin li zhengqiang Energy ＆ Environment Department Baoshan Iron ＆ Steel Co.Ltd. Shanghai 200941 China

This paper introduces the process flow, technical parameters and relevant features of Baosteel＇s No. 8 air separation unit （ASU） with a capacity of 60000m^3/h. It summarizes the commissioning work, which includes the adjustment of the air compressor,the system＇s naked cooling,the precooling system and the operation adjustment. It also provides detailed analyses on some failures which occurred in the commissioning. Through the modification of the design and the interlocks, the tripping probability of the air compressor was greatly reduced. Through the heating of the system and the control of the water cooler＇s nitrogen flow,the overproof content of carbon dioxide and fluctuation of oxygen flow were avoided. Nitrogen-block in the argon system was eliminated by the precise control of the argon rectification flow and argon content. All these solutions have been proved to be effective by practice.

关键词： air separation unit commissioning malfunction solution

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Initial research on the polarized reflectance of typical urban surface types measured by the Directional Polarimetric Camera

引用

Science China Earth Sciences 2011年第1期54卷 1199-1205页

作者： XIE DongHai GU XingFa CHENG TianHai YU Tao li zhengqiang CHEN XingFeng CHEN Hao GUO Jing State Key Laboratory of Remote Sensing Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing 100101 China Graduate University of Chinese Academy of Sciences BeOing 100049 China

This paper retrieves the bidirectional polarization distribution functions (BPDFs) of the distinct urban cover in the Pearl River Delta (PRD) region employing the high spatial resolution of multi-angle polarized measurements made by the Directional Polarimetric Camera (DPC).The BPDF operational products of MICROPOL and POLDER measurements were used to validate the BPDF products of the DPC,with the results demonstrating that the BPDF product of the DPC measurements accurately expresses the surface polarized *** polarized reflectance of distinct surface types in the PRD region was studied using the DPC *** results demonstrate that the polarized reflectances of different surface types differ and decrease as the normalized difference vegetation index *** polarized reflectance of a distinct surface type in the PRD region decreases with increasing scattering *** basic theory of investigating surface properties using multi-angle polarized measurements is proposed.

关键词： Directional Polarimetric Camera bidirectional polarization distribution function aerosol POLDER normalized difference vegetation index MICROPOL

来源：

维普期刊数据库

同方期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Regional transport of anthropogenic pollution and dust aerosols in spring to Tianjin——A coastal megacity in China

Regional transport of anthropogenic pollution and dust aeros...

引用

第十五届海峡两岸气胶技术研讨会

作者： Xiaoli SU Junji CAO zhengqiang li Key Lab of Aerosol Chemistry & Physics Institute of Earth EnvironmentChinese Academy of Sciences State Environmental Protection Key Laboratory of Satellite Remote Sensing Institute of Remote Sensing and Digital EarthChinese Academy of Sciences

Simultaneous measurements of columnar aerosol microphysical and optical properties,as well as PM chemical compositions,were made during two types of spring pollution episodes in Tianjin,a coastal megacity of *** events were investigated using field observations,satellite data,model simulations,and meteorological *** lower ? ngstr?m Exponent and the higher Aerosol Optical Depth on 29 March,compared with the earlier event on 26 March,implied a dominance of coarse mode particles — this was consistent with the differences in volume-size *** on the single scattering spectra,the dominant absorber(at blue wavelength) changed from black carbon during less polluted days to brown carbon on 26 March and dust on 29 *** concentrations of major PM species for these two episodes also differed,with the earlier event enriched in pollution-derived substances and the later with mineral dust *** formation mechanisms of these two pollution episodes were also *** 26 March episode was attributed to the accumulation of both local emissions and anthropogenic pollutants transported from the southwest of Tianjin under the control of high pressure *** the high aerosol loading on 29 March was caused by the mixing of transported dust from northwest source region with local urban *** mixing of transported anthropogenic pollutants and dust with local emissions demonstrated the complexity of springtime pollution in *** synergy of multi-scale observations showed excellent potential for air pollution study.

关键词： Multi-scale observations urban pollution dust transport formation mechanism

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：