检索结果-南通市图书馆

Technology and Infrastructure Considerations for E-Commerce in Chinese Agriculture

Agricultural Sciences in China 2007年第1期6卷 1-10页

作者： GENG Shu REN Tian-zhi wang mao-hua Department of Plant Sciences University of California Davis CA 95616 USA Institute of Natural Resource and Regional Planning Chinese Academy of Agricultural Sciences Beijing 100081 P.R.China Key Laboratory on Modern Precision Agriculture System Integration Research Ministry of Education/China Agricultural University Beijing 100081 P.R.China

Information technology （IT） was one of the most intensively studied and extensively applied technologies in the 20th century and its research and application will be even more accelerated in the 21st century. The impact of IT is more farreaching than any one may have had imagined, encompassing all facets and sectors of society. Economically, e-commerce generated more than $1.5 trillion in the US in 2004 and is projected to be 30, 15 and 2.6% of the total manufacturing, whole sales and retail sales in the US in 2006 respectively. IT research in agriculture has so far been particularly applied to such fields as precision farming and bioinformatics and in extension and farming practices. As such, its potential application in agricultural e-commerce has only begun to be explored. The United States Department of Agriculture has identified four different functions that e-commerce firms perform in the agricultural sector. They are：（1） information distribution, （2） input supply, （3） commodity trading floor, and （4） logistics/supply chain management. Unlike other industrial products, agricultural products are much more diverse and difficult to process and handle. For instance, fruits and vegetables are perishable and have to reach the market and the hands of consumers within a short period of time. One of the problems for IT applications in agriculture is the lack of standard measures in characteristics and quality of perishable produce and processing foods. Standards are pre-requisites for effective IT application and e-commerce. According to the Global Commerce Initiative, standards bring scalability, portability and affordability to the business process. Standards speed up the supply chain and reduce errors and protect technology investments and ensure system to system interaction and interoperability. Because the complexity of issues involved in standardization, the process of standardization must involve the input and discussion from all segments of the society. Being

关键词： information technology standardization e-commerce agricultural product

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

Molecular mechanism for the unusual enhancement of the second-step chemiluminescence production from the carcinogenic tetrabromohydroquinone and H2O_(2)

引用

Journal of Environmental Sciences 2024年第7期141卷 330-342页

作者： Zi-Han wang Chun-hua huang Zhi-Sheng Liu Li mao Ben-Zhan Zhu State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China College of Environment and Resources University of Chinese Academy of SciencesBeijing 100049China

We have found recently that two-step intrinsic hydroxyl radical(·OH)-dependent chemiluminescence(CL)could be produced by carcinogenic tetrahaloquinone and H_(2)O_(2).However,the first-step CL was too fast to clearly detect the stepwise generation of·OH and CL,and to distinguish the exact dividing point between the first-step and second-step *** we found that,extremely clear two-step intrinsic CL could be produced by the relative slow reaction of tetrabromohydroquinone(TBHQ)with H_(2)O_(2),which was directly dependent on the two-step·OH ***,the second-step,but not the first-step CL production of TBHQ/H_(2)O_(2)(CRET donor)was markedly enhanced by fluorescein(a typical xanthene dye,CRET acceptor)through a unique chemiluminescence resonance energy transfer(CRET)*** novel CRET system of TBHQ/H_(2)O_(2)/fluorescein was successfully applied for the sensitive detection of TBHQ with the detection limit as low as 2.5μmol/*** findings will help to develop more sensitive and highly efficient CL or CRET systems and specific CL sensor to detect the carcinogenic haloquinones,which may have broad environmental applications.

关键词： Two-step chemiluminescence Bromohydroquinone Hydrogen peroxide Hydroxyl radical CRET

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

Diverse responses of fungal functional groups to desertification in forest soils of Pinus densata on the Chinese Tibetan plateau

引用

JOURNAL OF FORESTRY RESEARCH 2024年第1期35卷 1-11页

作者： hua, Jiani Zhang, Jiangbao Song, Baohan wang, Tianyi Li, Jingji Yang, Nan mao, Lingfeng Nanjing Forestry Univ Coll Ecol & Environm Coinnovat Ctr Sustainable Forestry Southern China Lab Biodivers & Conservat Nanjing 210037 Peoples R China Chengdu Univ Technol Inst Ecol Resources & Landscape Architecture Chengdu 610059 Peoples R China

Rapid increase in desertification is an environmental concern, especially for the health and sustainability of ecosystems in changing climates. How ecosystems respond to such changes may be partially understood by studying interactions and performance of critically important groups such as soil fungi functional groups. This study investigated variations in diversities of three soil fungi functional guilds (saprotrophic, symbiotic, pathogenic) and influencing abiotic factors in a Pinus densata forest on the southeast Tibetan Plateau where desertification is intense. The results indicate desertification significantly decreased the proportion of dominant fungal guild-symbiotic fungi (mean relative abundance decreasing from 97.0% to 68.3%), in contrast to saprotrophic fungi (increasing from 2.7% to 25.7%) and pathogenic (from 0.3% to 5.9%). Soil pH had the most significant impact on fungal community structure and negatively correlated with symbiotic fungal richness, which was significantly lower in arid soils, and positively correlated with saprotrophic and pathogenic fungal alpha-diversity, which were abundant. Different community structures and regulators of the three fungi communities were observed, with pH, total phosphorus and ammonium (NH4+) as the main determinants. This study links the biotic and abiotic components during desertification and the interactions between them, and may be used as indicators of ecosystem health and for amendments to mitigate the effects of a changing climate.

关键词： Desertification Fungal diversity Saprotrophs Ectomycorrhizal fungi Climate change MULTIPLE SEQUENCE ALIGNMENT MICROBIAL COMMUNITIES MYCORRHIZAL FUNGI PLANT DIVERSITY ENZYME-ACTIVITY ECTOMYCORRHIZAL PH ECOSYSTEM FRAMEWORK GRADIENT

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

Enhancing the electrocatalytic performance of nitrate reduction to ammonia by in-situ nitrogen leaching

引用

Chinese Chemical Letters 2024年第2期35卷 564-569页

作者： Mimi Fu Yini mao hua wang Wei Luo Yimin Jiang Wei Shen Ming Li Rongxing He College of Chemistry and Chemical Engineering Southwest UniversityChongqing 400715China

Electrochemical nitrate reduction reaction (NITRR) is regarded as a “two birds-one stone” method for the treatment of nitrate contaminant in polluted water and the synthesis of valuable ammonia, which is retarded by the lack of highly reactive and selective electrocatalysts .Herein, for the first time, nickel foam supported Co_(4) N was designed as a high-performance NITRR catalyst by an in-situ nonmetal leaching-induced *** the optimal potential, the Co_(4) N/NF catalyst achieves ultra-high Faraday efficiency and NH_(3) selectivity of 95.4% and 99.4%, *** situ X-ray absorption spectroscopy (XAS), together with other experiments powerfully reveal that the nitrogen vacancies produced by nitrogen leaching are stable and play a key role in boosting nitrate reduction to *** calculations confirm that Co_(4) N with abundant nitrogen vacancies can optimize the adsorption energies of NO_(3)^(-) and intermediates, lower the free energy (Δ G ) of the potential-determining step (*NH_(3) to NH_(3) ) and inhibit the formation of N-containing *** addition, we also conclude that the nitrogen vacancies can stabilize the adsorbed hydrogen, making H_(2) quite difficult to produce, and lowering ΔG from *NO to *NOH, which facilitates the selective reduction of *** study reveals significant insights about the in-situ nonmetal leaching to enhance the NITRR activity.

关键词： Co4N Nitrate reduction In-situ nonmetal leaching Nitrogen vacancy Mechanism

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

CEOs’Diverse Career Experiences and the Effectiveness of Compensation Contracts:Evidence from Compensation Stickiness

引用

Journal of Systems Science and Systems Engineering 2024年第1期33卷 52-76页

作者： Shimin Sun Yongheng wang Yawen wang Mengyu mao School of Business Administration Northeastern UniversityShenyang110169China

CEO compensation stickiness represents an important indicator to measure the effectiveness of compensation *** study uses CEO career experience data and compensation stickiness data from Shanghai and Shenzhen A-share listed companies from 2015 to 2020 to investigate the compensation contracts’effectiveness of CEOs with diverse career *** findings are as follows:1)Compensation stickiness is more pronounced for CEOs with diverse career *** to the mechanism test,these CEOs with diverse career experiences can obtain compensation incentives by reducing corporate uncertainty perception and improving total factor *** approach leads to increased compensation stickiness and the effectiveness of compensation *** with diverse career experiences may receive excess compensation by raising agency costs,which intensifies compensation stickiness and weakens the effectiveness of compensation contracts.2)Compensation stickiness of CEOs with diverse career experiences is more significant in companies with lower investor protection,which brings about less effective compensation *** contrast,in companies with higher diversification,the compensation stickiness of CEOs with diverse career experiences is more significant,which delivers more effective compensation *** conclusions deepen the research of CEO compensation contracts and provide a helpful reference for CEO compensation management practices.

关键词： CEOs’diverse career experiences effectiveness of compensation contracts compensation stickiness agency problems incentive mechanisms

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

基于叉指阵列微电极的阻抗免疫传感器研究进展

引用

分析化学 2011年第10期39卷 1601-1610页

作者：颜小飞汪懋华安冬中国农业大学教育部现代精细农业系统集成研究重点实验室

叉指阵列微电极(Interdigitated array microelectrodes,IDAM)具有检出限低、灵敏度高和信噪比好等优点,近年来在分析化学领域引起了极大的关注。阻抗免疫传感器将IDAM与免疫测定技术相结合,通过抗原抗体的特异性反应引起IDAM之间介质... 详细信息

叉指阵列微电极(Interdigitated array microelectrodes,IDAM)具有检出限低、灵敏度高和信噪比好等优点,近年来在分析化学领域引起了极大的关注。阻抗免疫传感器将IDAM与免疫测定技术相结合,通过抗原抗体的特异性反应引起IDAM之间介质的阻抗变化实现对目标物的检测。本文分析了IDAM的特点、制作材料以及电极设计参数对系统检测性能的影响,评述了IDAM阻抗免疫传感器的工作原理、等效电路分析,综述了IDAM阻抗免疫传感器在食品安全分析和临床诊断领域中的应用,并讨论了目前研究中存在的问题及其发展趋势。

关键词：叉指阵列微电极阻抗免疫传感器等效电路综述

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

A direct polymeric carbon nitride/tungsten oxide Z-scheme heterostructure for efficient photocatalytic hydrogen generation via reforming of plastics into value-added chemicals

引用

Rare Metals 2024年第8期43卷 3771-3783页

作者： Rui-Zhe wang Zhi Lin Yi-Qing wang Kai-Ni Zhang Ge-Hong Zhang Jie Zhang Samuel S.mao Shao-hua Shen International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong UniversityXi'an 710049China School of Civil and Architecture Engineering Xi'an Technological UniversityXi'an 710021China Department of Mechanical Engineering University of California at BerkeleyBerkeleyCA94720USA

To promote charge transfer and separation for efficient photocatalysis,a direct Z-scheme heterostructure was constructed by coupling polymeric carbon nitride(PCN) and WO_(3).Interestingly,the obtained PCN/WO_(3)Z-scheme heterostructure could photocataly tic ally produce hydrogen and value-added chemicals(e.g.,formate and acetate) by reforming of plastic polylactic acid(PLA) in alkaline aqueous *** optimizing WO_(3) contents and reaction conditions,the obtained PCN/WO_(3)heterostructure exhibits much increased photocatalytic activity for PLA photoreforming under visible light,with hydrogen evolution rate reaching 402.90 μmol·g~(-1)·h~(-1),which is 3.5 times that of *** is revealed that the Z-scheme charge transfer between PCN and WO_(3) mainly contributes to the promoted charge separation and thus the improved photocatalytic ***,with h+and·OH experimentally evidenced as the predominant active species,a possible reaction pathway for the reforming of PLA into value-added chemicals(e.g.,formate and acetate)over PCN/WO_(3) Z-scheme heterostructure is cleared by monitoring the reaction intermediates and *** work paves a carbon neutrality and scalable route toward the synergistical production of hydrogen and value-added chemicals by utilizing and recycling plastic waste.

关键词： Carbon nitride Z-scheme heterojunction Plastic waste conversion Photocatalytic H_(2)production Value-added chemicals

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

Amorphous oxide semiconductor for monolithic 3D DRAM: an enabler or passer-by?

引用

National Science Review 2024年第3期11卷 19-20页

作者： Shujuan mao Guilei wang Chao Zhao Beijing Superstring Academy of Memory Technology

Since dynamic random-access memory(DRAM) was invented in 1968 and put to market in the 1970s, 1 transistor plus 1 capacitor(1T1C)(Fig. 1a) cells have been used to take advantage of their structural simplicity and ease...

关键词：

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Optimization Design of the Multi-Layer Cross-Sectional Layout of An Umbilical Based on the GA-GLM

引用

China Ocean Engineering 2024年第2期38卷 247-254页

作者： YANG Zhi-xun YIN Xu FAN Zhi-rui YAN Jun LU Yu-cheng SU Qi mao Yandong wang hua-lin Institute of marine machinery College of Mechanical and Electrical EngineeringHarbin Engineering UniversityHarbin 150001China State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDepartment of Engineering MechanicsDalian University of TechnologyDalian 116024China Ningbo Institube of Dalian University of Technology Ningbo 315040China

Marine umbilical is one of the key equipment for subsea oil and gas exploitation,which is usually integrated by a great number of different functional components with *** layout of these components directly affects manufacturing,operation and storage performances of the *** the multi-layer cross-sectional layout design of the umbilical,a quantifiable multi-objective optimization model is established according to the operation and storage *** the manufacturing factors,the multi-layering strategy based on contact point identification is introduced for a great number of functional ***,the GA-GLM global optimization algorithm is proposed combining the genetic algorithm and the generalized multiplier method,and the selection operator of the genetic algorithm is improved based on the steepest descent *** algorithm is used to find the optimal solution in the global space,which can converge from any initial layout to the feasible layout *** feasible layout solution is taken as the initial value of the generalized multiplier method for fast and accurate ***,taking umbilicals with a great number of components as examples,the results show that the cross-sectional performance of the umbilical obtained by optimization algorithm is better and the solution efficiency is ***,the multi-layering strategy is effective and *** design method proposed in this paper can quickly obtain the optimal multi-layer cross-sectional layout,which replaces the manual design,and provides useful reference and guidance for the umbilical industry.

关键词： umbilical cross-sectional layout multi-layers GA-GLM optimization

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

Modelling the formation and dissolution behavior of alumina agglomerate in the cryolite

引用

Particuology 2024年第3期86卷 211-222页

作者： Jiaqi wang mao Li Benjun Cheng Hesong Li School of Energy Science and Engineering Central South UniversityChangsha410083China

The presence of alumina agglomerates seriously affects the current efficiency of the aluminum electrolysis *** the dynamic dissolution process of agglomerates is essential to improve the current efficiency of aluminum electrolysis.A mathematical model is proposed to describe the different phenomena from the formation until complete dissolution of *** permeation and solidification processes of cryolite,a semi-analytical mathematical model is developed to formulate the formation,melting and dissolution processes of agglomerates,and the time duration for each stage is *** and heat mass transfer of agglomerates are explored based on the packing theory and mechanism of heat mass transfer in wet porous *** approach is applied to investigate the main factors affecting the dissolution stages and porosity of *** results show that the superheat has a great influence on the formation and melting stage,the diameter of agglomerates can reach 14.93 mm for 200 particles *** density decreases with the increase of agglomerated particle number,which varies in the range of 2.27-2.28 g/cm^(3).The average dissolution rate of agglomerates is about 1.83×10^(-5)-2.95×10^(-5) kg/s within the range of alumina concentration in this study.

关键词： Mathematical model Alumina agglomerate Porous media Packing theory Heatand mass transfer

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

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：