检索结果-南通市图书馆

Evaluation of Forest Damaged Area and Severity Caused by Ice-snow Frozen Disasters over Southern China with Remote Sensing

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 2019年第3期29卷 405-416页

作者： wang Xuecheng YANG Fei gao xing wang Wei ZHA Xinjie Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences State Key Laboratory of Resources and Environmental Information System University of Chinese Academy of Sciences Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application

The accurate assessment of forest damage is important basis for the forest post-disaster recovery process and ecosystem management. This study evaluates the spatial distribution of damaged forest and its damaged severity caused by ice-snow disaster that occurred in southern China during January 10 to February 2 in 2008. The moderate-resolution imaging spectroradiometer(MODIS)13 Q1 products are used, which include two vegetation indices data of NDVI(Normalized Difference Vegetation Index) and EVI(Enhanced Vegetation Index). Furtherly, after Quality Screening(QS) and Savizky-Golay(S-G) filtering of MODIS 13 Q1 data, four evaluation indices are obtained, which are NDVI with QS(QSNDVI), EVI with QS(QSEVI), NDVI with S-G filtering(SGNDVI) and EVI with S-G filtering(SGEVI). The study provides a new way of firstly determining the threshold for each image pixel for damaged forest evaluation, by computing the pre-disaster reference value and change threshold with vegetation index from remote sensing data. Results show obvious improvement with the new way for forest damage evaluation, evaluation result of forest damage is much close to the field survey data with standard error of only 0.95 and 1/3 less than the result that evaluated from other threshold method. Comparatively, the QSNDVI shows better performance than other three indices on evaluating forest damages. The evaluated result with QSNDVI shows that the severe, moderate, mild damaged rates of Southern China forests are 47.33%, 34.15%, 18.52%, respectively. By analyzing the influence of topographic and meteorological factors on forest-vegetation damage, we found that the precipitation on freezing days has greater impact on forest-vegetation damage, which is regarded as the most important factor. This study could be a scientific and reliable reference for evaluating the forest damages from ice-snow frozen disasters.

关键词： ice-snow disaster vegetation index forest remote sensing southern China

Fabrication of Pyrene and Tetraphenylethylene Nanostructures by a Hydrolysis-Assisted Co-Assembly

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2015年第2期33卷 207-212页

作者： Tianxiang wang Haisheng wang Lingbo xing Wenbo Zhang Changyou gao MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang UniversityHangzhouZhejiang 310027China

The poly(allylamine hydrochloride)-g-pyrene-tetraphenylethylene(PAH-g-Py-g-TPE)copolymers with different ratios of Py and TPE are synthesized by grafting 1-pyrenecarboxaldehyde(Py-CHO)and tetraphenylethylene-carboxaldehyde(TPE-CHO)to PAH via a Schiff base reaction in *** PAH-g-Py-g-TPE forms spherical micelles in water regardless of the ratios of Py and TPE,which can transform into different nanostructures after being incubated in pH 0 and pH 2 solutions,*** nanomaterials including nanoparticles(NPs),nano-rods(NRs),nanotubes(NTs)and nanoribbons(NBs)are composed of Py-CHO and TPE-CHO with different ratios,and emit fluorescence with colors different from the pure Py NRs and NTs,and TPE NPs.

关键词： pyrene tetraphenylethylene hydrolysis nanostructures self-assembly

Recent Progress on Bismuth-based Nanomaterials for Electrocatalytic Carbon Dioxide Reduction

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

Chemical Research in Chinese Universities 2020年第3期36卷 410-419页

作者： YANG Chan CHAI Jiaxin wang zhe xing Yonglei PENG Juan YAN Qingyu State Key Laboratory of High-efficiency Coal Utilization ami Green Chemical Engineering School of Chemistry and Chemical EngineenngNingxia UniversityYinchuan 750021P.R.China Energy Research Institute at Nanyang Technological University(ERI@N) Natiyang Technological University639798Singapore School of Materials Science and Engineering Nanyang Technological University639798Singapore

Due to the burning of fossil fuels,the level of carbon dioxide(CO2)in the atmosphere gradually rises,leading to serious greenhouse effect and environmental *** reduction of CO2 is currently an efficient way to convert CO2 to value-added ***(Bi)-based nanomaterials have raised great interests due to their excellent activity and high selectivity to electrocatalytic CO2 *** this review,the fundamental principles of electrochemical CO2 reduction reaction(CO2RR)are introduced at ***,the recent development of Bi-based electrocatalytic materials including Bi with various nanostructures(nanoparticle,***.),Bi-based compounds(Bi oxide,bimetal chalcogenide,etc.),and Bi/C nanocomposites are *** the end,the future prospects and challenges of electrocatalysts for CO2 reduction are discussed.

关键词： Electrocatalysis Carbon dioxide reduction Nanostructure Compound Nano-composite

The existence of radial k-admissible solutions for n-dimension system of k-Hessian equations

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

Applied Mathematics(A Journal of Chinese Universities) 2023年第2期38卷 310-316页

作者： HE xing-yue wang Jing-jing gao Cheng-hua Department Mathematics and Statistics Northwest Normal UniversityLanzhou 730070China

In this paper,we focus on a general n-dimension system of k-Hessian *** introducing some new suitable growth conditions,the existence results of radial k-admissible solutions of the k-Hessian system are *** approach i... 详细信息

关键词： k-Hessian equations radial k-admissible solutions existence xed-point theorem

Gut microbiota dysbiosis in patients with nonalcoholic fatty liver disease

在线全文

学校读者我要写书评

暂无评论

Hepatobiliary & Pancreatic Diseases International 2017年第4期16卷 375-381页

作者： feng Shen Rui-Dan zheng xing-Qiang Sun Wen-Jin Ding Xiao-Ying wang Jian-gao Fan Department of Gastroenterology Xinhua HospitalShanghai Jiaotong University School of MedicineShanghai 200092China Department of Pathology Xinhua HospitalShanghai Jiaotong University School of MedicineShanghai 200092China Research and Therapy Centre for Liver Disease Zhengxing HospitalZhangzhou 363000China Department of Microbial Genomics Research BGI ShenzhenShenzhen 518083China

BACKGROUND: Gut microbiota plays a significant role in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). This study aimed to assess the contribution of gut microbiota dysbiosis to the pathogenesis of NAFLD. METHODS: Forty-seven human feces samples (25 NAFLD patients and 22 healthy subjects) were collected and 16S rDNA amplicon sequencing was conducted on Hiseq 2000 platform. Discrepancy of species composition between controls and NAFLD group was defined by Metastats analysis under P value <0.01. RESULTS: NAFLD patients harbored lower gut microbiota diversity than healthy subjects did. In comparison to the control group, the Proteobacteria (13.50%) and Fusobacteria (2.76%) phyla were more abundant in NAFLD patients. Additionally, the Lachnospiraceae (21.90%), Enterobacteriaceae (12.02%), Erysipelotrichaceae (3.83%), and Streptococcaceae (1.39%) families, as well as the Escherichia_Shigella (10.84%), Lachnospiraceae_Incertae_Sedis (7.79%), and Blautia (4.95%) genera were enriched in the NAFLD group. However, there was a lower abundance of Prevotella in the NAFLD group than that in the control group (5.83% vs 27.56%, P<0.01). The phylum Bacteroidetes (44.63%) also tended to be more abundant in healthy subjects, and the families Prevotellaceae (28.66%) and Ruminococcaceae (26.44%) followed the same trend. Compared to those without non-alcoholic steatohepatitis (NASH), patients with NASH had higher abundance of genus Blautia (5.82% vs 2.25%; P=0.01) and the corresponding Lachnospiraceae family (24.33% vs 14.21%; P<0.01). Patients with significant fibrosis had a higher abundance of genus Escherichia_Shigella (12.53% vs 1.97%; P<0.01) and the corresponding Enterobacteriaceae family (13.92% vs 2.07%; P<0.01) compared to those with F0/F1 fibrosis. CONCLUSIONS: NAFLD patients and healthy subjects harbor varying gut microbiota. In contrast to the results of previous research on children, decreased levels of Prevotella might be detrimental for adults with NAFLD. Th

关键词： gut microbiota fatty liver disease non-alcoholic steatohepatitis fibrosis

Controllable synthesis of MnO_(2)/iron mesh monolithic catalyst and its significant enhancement for toluene oxidation

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2023年第2期34卷 338-341页

作者： Meijuan Qi zhe Li Zhang Zhang Yanshan gao Qiang wang Beijing Key Lab for Source Control Technology of Water Pollution College of Environmental Science and EngineeringBeijing Forestry UniversityBeijing 100083China Engineering Research Center for Water Pollution Source Control&Eco-remediation College of Environmental Science and EngineeringBeijing Forestry UniversityBeijing 100083China Beijing Municipal Ecological and Environmental Monitoring Center Beijing 100048China

A series of monolithic MnO_(2)/iron mesh (IM) catalysts for oxidation of toluene were successfully prepared by using in situ hydrothermal ***_(2)can grow firmly on the IM substrates surface with a shedding rate of only 0.14%.Due to the highest O_(ads) and high-valent Mn^(4+) and Fe^(3+) elements,the temperature at 50% and 90% toluene conversion (T_(50%) and T_(90%)) was 252 and 265℃,respectively for the best performance catalyst (hydrothermal temperature of 80℃,hydrothermal time of 12 h,and precursor manganese ion concentration of 0.03 mol/L).The catalysts also presented good water resistance and cycle ***-situ DRIFTS results suggesting that toluene was first rapid transformed into the reaction intermediate species (benzoate species) and then converted to CO_(2)and H_(2)***,this work provides a new direction for the research and application of IM-based monolithic catalysts.

关键词： Toluene oxidation Iron mesh monoliths catalysts MnO_(2) Resistance properties Reaction mechanism

Damage analysis of POZD coated square reinforced concrete slab under contact blast

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2022年第9期18卷 1715-1726页

作者： Wei wang Qing Huo Jian-chao Yang Jian-hui wang xing wang Wei-liang gao Key Laboratory of Impact and Safety Engineering (Ningbo University)Ministry of EducationNingbo315211ZhejiangChina Institute of Defence Engineering AMS PLALuoyang 471023China Institute of Advanced Energy Storage Technology and Equipment Ningbo UniversityNingbo315211ZhejiangChina

High efficiency, environmental protection and sustainability have become the main theme of the development of the protection engineering, requiring that the components not only meet the basic functions, but also have chemical properties such as acid and alkali corrosion resistance and aging resistance. Polyisocyanate-oxazodone(POZD) polymer has the above characteristics, it also has the advantages of strong toughness, high strength and high elongation. The concrete slab sprayed with POZD material has excellent anti-blast performance. In order to explore the damage characteristics of POZD sprayed concrete slabs under the action of contact explosion thoroughly, the contact explosion test of POZD concrete slabs with different charges were carried out. On the basis of experimental verification,numerical simulation were used to study the influence of the thickness of the POZD on the blast resistance of the concrete slab. According to the test and numerical simulation results that as the thickness of the coating increases, the anti-blast performance of the concrete slab gradually increases,and the TNT equivalent required for critical failure is larger. Based on the above analysis, empirical expressions on normalized crater diameter, the normalized spall diameter and normalized spall diameter are obtained.

关键词： Contact exposion Square reinforced concrete slab POZD coating Numerical simulation

Kinetic and thermodynamic synergy of organic small molecular additives enables constructed stable zinc anode

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2023年第9期84卷 62-72页

作者： Yang gao Mingshan wang Hao wang Xinpeng Li Yuanwei Chu Zhicheng Tang Yuanlong feng Jiaqi wang Yong Pan Zhiyuan Ma zhenliang Yang Dan Zhou xing Li School of New Energy and Materials Energy Storage Research InstituteSouthwest Petroleum UniversityChengdu 610500SichuanChina Institute of Materials China Academy of Engineering PhysicsMianyang 621907SichuanChina Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and TechnologyBeijing 100083China

An organic small molecule additive zinc formate is introduced to construct stable Zn metal interphase by electrochemical kinetic control and thermodynamic *** partially forms a water-formate concomitant dipole layer at the internal Helmholtz electrical double layers(HEDLs) under the preferential adsorption function of formate on Zn surface,reducing the occurrence of side reactions at phase ***,free formate in HEDLs regulates the Zn^(2+) solvation sheath structure to accelerate the desolvation,transference,and deposition kinetics of Zn^(2+).Besides,the hydrolysis reaction of zinc formate increases the hydrogen evolution overpotential,inhibiting the thermodynamic tendency of hydrogen ***,it presents stable cycle for more than 2400 h at 5 mA cm^(-2),as well as an average Coulombic efficiency of 99.8% at 1 A g^(-1) after 800 cycles in the Zn‖VO_(2) full *** interphase engineering strategy zinc anode by organic small molecular brings new possibility towards high-performance aqueous zinc-ion batteries.

关键词： Zn anode Organic small molecule Aqueous zinc-ion battery Zinc formate

Automated String Constraints Solving for Programs Containing String Manipulation Functions

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2017年第6期32卷 1125-1135页

作者： Xu-Zhou Zhang Yun-Zhan Gong Ya-Wen wang Ying xing Ming-zhe Zhang State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China Automation School Beijing University of Posts and Telecommunications Beijing 100876 China

The ability to solve various constraints is a principal factor of automatic constraint solvers. Most object-oriented languages treat a character string as a primitive data type which is manipulated by string library functions. Most constraint solvers have limitations on their input constraints, such as strong restrictions on the expressiveness of constraints or lack of the ability to solve hybrid constraints. These limitations hinder applying automated constraint solvers on program analysis techniques for programs containing strings and string manipulation functions. We propose an approach to automatically solve program constraints involving strings and string manipulation functions. Based on the character array model, we design a constraint language which contains primitive operations to precisely describe the constraints of commonly used string manipulation functions. The translated string constraints together with numeric constraints are then solved by a two- phase test generation procedure： firstly, a partial solution is obtained to satisfy the arithmetic constraints of the position variables, and the solution is utilized to simplify the string constraints into pure character array constraints; secondly, the pure array constraints are solved by an off-the-shelf array-specific theory based constraint solver. We integrate the approach into an automated testing tool to support the generation of string test cases, and then perform experiments. The results of the experiments prove that the integration of the proposed approach promotes the testing coverage of the existing testing tool, and the integrated tool has an advantage of handling specific string manipulation functions compared with an existing string solver.

关键词： string constraints solving satisfaction module theory program analysis software testing automated testinput generation