检索结果-南通市图书馆

国际贸易与发展中国家的城市化:来自亚洲的证据（英文）

在线全文

学校读者我要写书评

暂无评论

Social Sciences in china 2015年第2期36卷 186-204页

作者：章元万广华 Wang Wen'e china center for economic Studies Fudan University research Institute for Indian Ocean Economies Yunnan University of Finance and Economics

余粮率和粮食贸易与发展中国家的城市化进程紧密相关,但是现有文献对这个问题没有给予足够的重视。本文通过建立理论模型,论证了封闭经济条件下余粮率对城市化水平提高的约束作用,以及开放经济条件下,粮食贸易会通过影响余粮率来影响城... 详细信息

余粮率和粮食贸易与发展中国家的城市化进程紧密相关,但是现有文献对这个问题没有给予足够的重视。本文通过建立理论模型,论证了封闭经济条件下余粮率对城市化水平提高的约束作用,以及开放经济条件下,粮食贸易会通过影响余粮率来影响城市化水平。基于亚洲发展中国家1993-2010年的面板数据,本文对理论模型的推论进行了检验,发现国际贸易总体上与城市化水平负相关,但是谷物贸易和非谷物贸易与城市化水平的关系不同,前者与它正相关,而后者与它负相关。另外,谷物净进口能够显著促进城市化,原因在于谷物净进口放松了国内余粮率对于城市化水平的约束。本文研究结果表明,发展中国家可以采取支持粮食生产或在保证粮食安全的前提下适当进口粮食的政策,这些政策可以放松余粮率的约束来促进城市化水平的提高。

关键词：城市化谷物贸易余粮亚洲

Maintenance Awareness of Student Group about College Historical Buildings

在线全文

学校读者我要写书评

暂无评论

Journal of Donghua University(English Edition) 2019年第3期36卷 293-299页

作者：李亮周晓健 School of Art Design Shanghai University of Engineering ScienceShanghai 201620China China Center for Special Economic Zone Research Shenzhen UniversityShenzhen 518060China

In order to investigate the maintenance awareness of student group on historical buildings in colleges,this paper employs fuzzy comprehensive evaluation method and determines the evaluation system of maintenance awareness.Through sampling survey,it s found that maintenance awareness of college students belongs to medium level,and emotional identity level is high.However,protection behavior is little,which is due to the lack of protection knowledge and college propaganda.What s more,the usage of historical buildings also affects the maintenance awareness level.

关键词： maintenance awareness fuzzy comprehensive evaluation college campus historical buildings

Characterization,reactivity,source apportionment,and potential source areas of ambient volatile organic compounds in a typical tropical city

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2023年第1期123卷 417-429页

作者： Xiaocong Cao Qiao Xing Shanhu Hu Wenshuai Xu Rongfu Xie Aidan Xian Wenjing Xie Zhaohui Yang Xiaochen Wu Hainan research Academy of Environmental Sciences Haikou 571126China National Pilot zone for Ecological Conservation(Hainan)research center Haikou 571126China

Based on one-year observation,the concentration,sources,and potential source areas of volatile organic compounds(VOCs)were comprehensively analyzed to investigate the pollution characteristics of ambient VOCs in Haikou,china.The results showed that the annual average concentration of total VOCs(TVOCs)was 11.4 ppb V,and the composition was dominated by alkanes(8.2 ppb V,71.4%)and alkenes(1.3 ppb V,20.5%).The diurnal variation in the concentration of dominant VOC species showed a distinct bimodal distribution with peaks in the morning and evening.The greatest contribution to ozone formation potential(OFP)was made by alkenes(51.6%),followed by alkanes(27.2%).The concentrations of VOCs and nitrogen dioxide(NO_(2))in spring and summer were low,and it was difficult to generate high ozone(O_(3))concentrations through photochemical reactions.The significant increase in O_(3)concentrations in autumn and winter was mainly related to the transmission of pollutants from the northeast.Traffic sources(40.1%),industrial sources(19.4%),combustion sources(18.6%),solvent usage sources(15.5%)and plant sources(6.4%)were identified as major sources of VOCs through the positive matrix factorization(PMF)model.The southeastern coastal areas of china were identified as major potential source areas of VOCs through the potential source contribution function(PSCF)and concentration-weighted trajectory(CWT)models.Overall,the concentration of ambient VOCs in Haikou was strongly influenced by traffic sources and long-distance transport,and the control of VOCs emitted from vehicles should be strengthened to reduce the active species of ambient VOCs in Haikou,thereby reducing the generation of O_(3).

关键词： Volatile organic compounds(VOCs) Ozone Positive matrix factorization(PMF) model Backward trajectory Potential source area

Super broadband absorbing hierarchical CoFe alloy/porous carbon@carbon nanotubes nanocomposites derived from metal-organic frameworks

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2022年第23期118卷 218-228页

作者： Siyao Guo Yunfeng Bao Ying Li Hailong Guan Dongyi Lei Tiejun Zhao Baomin Zhong Zhihong Li School of Civil Engineering Qingdao University of TechnologyQingdao 266033China Postdoctoral Workstation Guangdong Dongpeng Holding Company LimitedGuangdong 528031China Cooperative Innovation center of Engineering Construction and Safety in Shandong Blue economic zone Qingdao University of TechnologyQingdao 266033China National Key Laboratory of Science and Technology for National Defence on Advanced Composites in special Environments Harbin Institute of TechnologyHarbin 150080China

The exploitation of electromagnetic wave absorption(EMA) materials has attracted ever-increasing attention,not only because electromagnetic wave(EMW) originated from overuse of electronic products has threatened human' health seriously,but also because EMA materials can effectively protect radar stealth from being detected.However,it is still a challenge to obtain broadband and efficient EMA materials to satisfy practical applications.In this work,we developed a series of hierarchical CoFe alloy/porous carbon@carbon nanotubes(CoFe/PC@CNTs) nanocomposites through revising the proportion of Fe^(2+) in the metal-organic frameworks(MOFs)(CoFe-ZIF) precursor and one-step simple pyrolysis process.The cross deposition between CoFe alloy,carbon nanotubes(CNTs),and porous carbon(PC) formed a double conductive network,favoring for achieving excellent EMA property.Surprisingly,when the filler mass ratio is only 10 wt%,the optimized CoFe/PC@CNTs nanocomposites display the best EMA capability,whose minimum reflection loss(RL_(min)) value is-68.94 dB at 13.69 GHz and the effective absorption band(EAB,<-10 dB) reaches up 9.14 GHz with a matching thickness of 2.63 mm.In addition,the largest EAB can achieve up to 11 GHz(3.35-14.35 GHz) during all matching thicknesses.The splendid EMA performance benefits the favorable dielectric loss provided by the double conductive network,the good magnetic loss benefited from the evenly distributed CoFe alloy,the excellent impedance matching,rich transmission paths,and multiple polarization.Therefore,such EMA materials with super broadband absorbing provide desirable candidates for lightweight and high-efficient microwave absorbers.

关键词： Electromagnetic wave absorption CoFe alloy/porous carbon@carbon nanotubes nanocomposites Broadband absorbing Metal-organic frameworks

Polyoxometalate-MnO_(2)film structure with bifunctional electrochromic and energy storage properties

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

Journal of Materiomics 2023年第2期9卷 269-278页

作者： Shi-Ming Wang Yuan-Hang Jin Tao Wang Kai-Hua Wang Lin Liu Light Industry College Liaoning University66 Chongshan Middle RoadHuanggu DistrictShenyang110036China College of Chemistry Liaoning University66 Chongshan Middle RoadHuanggu DistrictShenyang110036China Shenyang Liaohe special Glass Factory 10 AZhongyang RoadOffshore Economic Development ZoneLiaozhong DistrictShenyangChina

The polyoxometalates-based electrochromic energy storage devices(POMs-EESDs)were constructed using P2W17O6111coated TiO_(2)as the working electrode and MnO_(2)film as the counter electrode.The MnO_(2)films with different thicknesses acted as the charge balancing layer.The device showed bifunctional of enhanced EC and energy storage properties along with high durability and cycle stabilities after the introduction of MnO_(2)film.The optimistic thickness of MnO_(2)was found to be 345 nm through balancing the optical modulation and the energy storage properties.For the EC aspect,the optical contrast was enhanced by four times under the potential step of2.0/1.0 V.The MnO_(2)film also introduces high capacitance leading to the device can be used as a transparent capacitor.It is the first time to construct high-performance POMs-based EESD only by introducing a simple charge balancing(MnO_(2))layer in the device.Moreover,the mechanism of the MnO_(2)layer towards the performance improvement of the POMs-based EESDs was also explained.

关键词： Electrochromic energy storage device Polyoxometalates Electrochromism Capacitor

Structure elucidation and in vitro rat intestinal fermentation properties of a novel sulfated glucogalactan from Porphyra haitanensis

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 Science and Human Wellness 2023年第2期12卷 596-606页

作者： Peilin Chen Lu Liu Zirun Cheng Yi Zhang Baodong Zheng Xiaoke Hu Hongliang Zeng Engineering research center of Fujian-Taiwan special Marine Food Processing and Nutrition Ministry of EducationFuzhou 350002China College of Food Science Fujian Agriculture and Forestry UniversityFuzhou 350002China c Fujian Provincial Key Laboratory of Quality Science and Processing Technology in special Starch Fujian Agriculture and Forestry UniversityFuzhou 350002China Key Laboratory of Coastal Biology and Bioresource Utilization Yantai Institute of Coastal Zone ResearchChinese Academy of SciencesYantai 264003China

This study was to investigate the structure and rat fecal microbial fermentation properties of a polysaccharide fraction(PHP2)isolated from the red marine alga Porphyra haitanensis.PHP2 was characterized as a sulfated glucogalactan,with a hypothetical backbone structure of→4)Gα(1→6)G4 Sβ(1→4)Glc(1→and a side chain of Man(1→6)Glc.PHP2 had an irregular spherical chain conformation.The 16 S r RNA sequence analysis revealed that PHP2 modulated the rat fecal micro-flora composition,with a similar effect to inulin,changing the dominant genus(Lactobacillus and Escherichia-Shigella)and promoting the growth of organisms that degrade sulfur-containing polysaccharides,such as Desulfovibrio,Ruminococcaceae_UCG-005,and Ruminococcus_2.PHP2 can promote production of acetic,propionic and butyric acid by rat fecal micro-flora.Prediction of metabolic function suggested that PHP2 could modulate cholesterol metabolism.The sulfated glucogalactan fermentation behavior may be associated with its monosaccharide composition,chain branching and chain conformation.PHP2 appeared to have considerable potential as functional food,and was associated with sulfur-containing polysaccharides in general.

关键词： Porphyra haitanensis Structure characterization Fecal microflora Short-chain fatty acids Metabolic function prediction Polysaccharide

不同应力路径下小跨度隧洞围岩的宏细观破坏机理

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2022年第5期29卷 1616-1629页

作者：刘和艺丛宇张黎明郑颖人王在泉阿比尔的刘立鹏 College of Civil of Engineering Qingdao University of TechnologyQingdao 266033China Cooperative Innovation center of Engineering Construction and Safety in Shandong Blue economic zone Qingdao University of TechnologyQingdao 266033China Chongqing Jiaotong University Chongqing 400074China State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin china Institute of Water Resources and Hydropower ResearchBeijing 100048China

为探究小跨度隧洞围岩在不同应力路径下的破坏机制,依据现场工况设计相似模型试验可以直观了解围岩的破坏过程,同时数值模拟技术为洞悉岩体内部的破坏机理提供了可视化手段。本文依托某隧洞工程设计了相似模型的加、卸荷破坏试验,并利... 详细信息

为探究小跨度隧洞围岩在不同应力路径下的破坏机制,依据现场工况设计相似模型试验可以直观了解围岩的破坏过程,同时数值模拟技术为洞悉岩体内部的破坏机理提供了可视化手段。本文依托某隧洞工程设计了相似模型的加、卸荷破坏试验,并利用颗粒流分析软件PFC进行数值仿真。对比宏、细观两种尺度下的试验发现,隧洞两侧直墙中部岩体的切向应力峰值最低,该处易受拉破坏。拱肩和拱脚处的围岩因应力集中而松动,该处产生的裂隙与直墙处裂隙贯通后将岩体切割成块是隧洞破坏的主要形式。开挖卸荷的应力路径下,隧洞整体的承载能力更强,但破坏时剥落的岩体更加破碎,围岩的损伤深度更大且内部剪切裂纹占比更多,最终形成的破坏面接近“V”型,同时开挖卸荷还会形成开挖扰动区,使拱顶和拱底处岩体的切向应力峰值降低,部分岩体的承载能力下降。

关键词：应力路径相似模型试验 PFC仿真开挖卸荷宏观和细观尺度

Spatial Optimization and Reconstruction of Old Communities under the Background of Aging

在线全文

学校读者我要写书评

暂无评论

Journal of Landscape research 2024年第2期16卷 51-53,60页

作者： LI Yiwen LI Daoyong HE Qilin School of Architecture and Art North China University of TechnologyBeijing 100144China Planning and Comprehensive Affairs center of Beijing economic and Technological Development zone Beijing 100176China

As aging becomes increasingly serious,how to make the life of the elderly more convenient and comfortable has become one of the social problems to be solved urgently.Old residential areas are one of spaces where the elderly gather.In this paper,the prominent problems in the community space of existing old residential areas that are not conducive to the life of the elderly were analyzed,and corresponding countermeasures to transform the community space were put forward.It is hoped that public space can play its due value and make old residential areas glow with new vitality.

关键词： Aging adaptability Community public space Elderly care community Space transformation

Non-Markovianity Measure Based on Brukner–Zeilinger Invariant Information for Unital Quantum Dynamical Maps

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

Communications in Theoretical Physics 2017年第3期67卷 255-260页

作者：贺志朱烈强李莉 College of Physics and Electronics Hunan Province Cooperative Innovation Center for The Construction and Development of Dongting Lake Ecological Economic Zone Hunan University of Arts and Science Changde 415000 China

A non-Markovianity measure based on Brukner–Zeilinger invariant information to characterize nonMarkovian effect of open systems undergoing unital dynamical maps is proposed. The method takes advantage of non-increasing property of the Brukner–Zeilinger invariant information under completely positive and trace-preserving unital maps. The simplicity of computing the Brukner–Zeilinger invariant information is the advantage of the proposed measure because of mainly depending on the purity of quantum state. The measure effectively captures the characteristics of non-Markovianity of unital dynamical maps. As some concrete application, we consider two typical non-Markovian noise channels, i.e., the phase damping channel and the random unitary channel to show the sensitivity of the proposed measure. By investigation, we find that the conditions of detecting the non-Markovianity for the phase damping channel are consistent with the results of existing measures for non-Markovianity, i.e., information flow, divisibility and quantum mutual information. However, for the random unitary channel non-Markovian conditions are same to that of the information flow, but is different from that of the divisibility and quantum mutual information.

关键词：量子动力学信息计算马尔科夫性单位非马尔科夫动态地图噪声信道马尔可夫