期刊文献+
共找到26,307篇文章
< 1 2 250 >
每页显示 20 50 100
MAPK signal pathways in the regulation of cell proliferation in mammalian cells 被引量:119
1
作者 WEI ZHANG, Hui tu LIU The Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, Beijing 100875, China 《Cell Research》 SCIE CAS CSCD 2002年第1期9-18,共10页
MAPK families play an important role in complex cellular programs like proliferation, differentiation, development, transformation, and apoptosis. At least three MAPI(families have been characterized: extracellular si... MAPK families play an important role in complex cellular programs like proliferation, differentiation, development, transformation, and apoptosis. At least three MAPI(families have been characterized: extracellular signal-regulated kinase (ERK), Jun kinase (JNK/SAPK) and p38 MAPK. The above effects are fulfilled by regulation of cell cycle engine and other cell proliferation related proteins. In this paper we discussed their functions and cooperation with other signal pathways in regulation of cell proliferation. 展开更多
关键词 MAPK ER.K JNK/SPAK p38 cell proliferation cross-talk.
下载PDF
Petrogenesis of the Neopro-terozoic bimodal volcanic rocks along the western margin of the Yangtze Block:New constraints from Hf isotopes and Fe/Mn ratios 被引量:93
2
作者 LI Xianhua QI Changshi +4 位作者 LIU Ying LIANG Xirong tu Xianglin XlE Liewen YANG Yueheng 《Chinese Science Bulletin》 SCIE EI CAS 2005年第21期2481-2486,共6页
High-precision major element and Hf isotope data are reported for the Neoproterozoic Suxiong volcanic rocks along the western margin of the Yangtze Block. These volcanic rocks have variable εHf(T) values and Fe/Mn ra... High-precision major element and Hf isotope data are reported for the Neoproterozoic Suxiong volcanic rocks along the western margin of the Yangtze Block. These volcanic rocks have variable εHf(T) values and Fe/Mn ratios. The relatively primitive basalts have high Fe/Mn ratios and high Hf-Nd isotopic compositions, indicating that they were generated by partial melting of garnet clinopyroxene in mantle plume at high pressure. Thus, the Suxiong basalts are genetically related to the proposed Neoproterozoic super-plume. On the contrary, a few differentiated basalts have low Fe/Mn ratios and low Hf-Nd isotopic compositions. They are likely to experience assimilation-fractional crystallization process. The Suxiong rhyolites have consistent Hf and Nd model ages of 1.3―1.4 Ga. They are likely generated by shallow dehydration melting of pre-existing young arc igne-ous rocks associated with the basaltic underplating/intrusion in a continental rift. 展开更多
关键词 火山岩 页岩 同位素 玄武岩 岩石学
原文传递
Clinical Features of Adult/Adolescent Atopic Dermatitis and Chinese Criteria for Atopic Dermatitis 被引量:80
3
作者 Ping Liu Yan Zhao +24 位作者 Zhang-Lei Mu Qian-Jin Lu Qian-Jin L U Li Zhang Xu Yao Min Zheng Yi-Wen Tang Xin-Xiano Lu Xiu-Juan xia You-Kun Lin Yu-Zhen Li Cai-Xia tu Zhi-Rong Yao Jin-Hua Xu Wei Li Wei Lai Hui-Min Yang Hong-Fu Xie Xiu-Ping Han Zhi-Qiang Xie Xiang Nong Zai-Pei Guo Dan-Qi Deng Tong-Xin Shi Jian-Zhong Zhang 《Chinese Medical Journal》 SCIE CAS CSCD 2016年第7期757-762,共6页
Background: Atopic dermatitis (AD) is an inflammatory skin disease characterized by chronic recurrent dermatitis with profound itching. Most patients have personal and/or family history of atopic diseases. Several ... Background: Atopic dermatitis (AD) is an inflammatory skin disease characterized by chronic recurrent dermatitis with profound itching. Most patients have personal and/or family history of atopic diseases. Several criteria have been proposed for the diagnosis of AD. Although the clinical features of childhood AD have been widely studied, there has been less large-scale study on adult/adolescent AD. The aim of this study was to investigate the clinical features of adult/adolescent patients with chronic symmetrical eczemaJAD and to propose Chinese diagnostic criteria for adult/adolescent AD. Methods: A hospital-based study was performed. Forty-two dermatological centers participated in this study. Adult and adolescent patients (12 years and over) with chronic symmetrical eczema or AD were included in this study. Questionnaires were completed by both patients and-investigators. The valid questionnaires were analyzed using EpiData 3.1 and SPSS 17.0 software. Results: A total of 2662 valid questionnaires were collected (1369 male and 1293 female). Of all 2662 patients, 2062 (77.5%) patients had the disease after 12 years old, while only 600 (22.5%) patients had the disease before 12 years old, suggesting late-onset eczema/AD is common. Two thousand one hundred and thirty-nine (80.4%) patients had the disease for more than 6 months. One thousand one hundred and forty-four (43.0%) patients had a personal and/or family history of atopic diseases. One thousand five hundred and forty-eight (58.2%) patients had an elevated total serum IgE and/or eosinophilia and/or positive allergen-specific IgE. Based on these clinical and laboratory features, we proposed Chinese criteria for adult/adolescent AD. Of all 2662 patients, 60.3% were satisfied with our criteria, while only 48.2% satisfied with Hanifin Rajka criteria and 32.7% satisfied with Williams criteria, suggesting a good sensitivity of our criteria in adult/adolescent AD patients. Conclusion: Late-onset of eczema or AD is common. Th 展开更多
关键词 Adolescents and Adults Atopic Dermatitis Clinical Features Diagnostic Criteria ECZEMA
原文传递
Heavy metal pollution in intertidal sediments from Quanzhou Bay, China 被引量:74
4
作者 YU Ruilian YUAN Xing +2 位作者 ZHAO Yuanhui HU Gongren tu Xianglin 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2008年第6期664-669,共6页
The concentrations of eight heavy metals (Cu, Zn, Pb, Cd, Cr, Ni, Hg, and As) in the intertidal surface sediments from Quanzhou Bay were determined to evaluate their levels and spatial distribution due to urbanizati... The concentrations of eight heavy metals (Cu, Zn, Pb, Cd, Cr, Ni, Hg, and As) in the intertidal surface sediments from Quanzhou Bay were determined to evaluate their levels and spatial distribution due to urbanization and economic development of Quanzhou region, southeast China. The ranges of the measured concentrations in the sediments are as follows: 24.8-119.7 mg/kg for Cu, 105.5-241.9 mg/kg for Zn, 34.3-100. 9 mg/kg for Pb, 0.28-0. 89 mg/kg for Cd, 51.1-121.7 mg/kg for Cr, 16.1-45.7 mg/kg for Ni, 0.17-0.74 mg/kg for Hg, and 17.7-30.2 mg/kg for As. The overall average concentrations of above metals exceed the primary standard criteria but meet the secondary standard criteria of the Chinese National Standard of Marine Sediment Quality. Several contents of Cu and Hg exceed the secondary standard criteria at some stations. The results of geoaccumulation index (Igeo) show that Cd causes strong pollution in most of the study area. There are no significant correlations among most of these heavy metals, indicating they have different anthropogenic and natural sources. Some locations present severe pollution by heavy metals depending on the sources, of which sewage outlets, aquatic breeding, and commercial ports are the main sources of contaminants to the area. 展开更多
关键词 heavy metal intertidal sediment CONTAMINATION geoaccumulation index Quanzhou Bay
下载PDF
Combined Pollution and Pollution Index of Heavy Metals in Red Soil 被引量:56
5
作者 CHEN HUAIMAN ZHENG CHUNRONG WANG SHENQIANG and tu CONG(Institute of Soil Science, the Chinese Academy of Sciences, P.O. Box 821, Naroing 210008 China) 《Pedosphere》 SCIE CAS CSCD 2000年第2期117-124,共8页
A field experiment was conducted to study the effects of Pb, Cd, Cu, Zn and As coexisting in red soilon growth of rice (Oryza sativa L.), mung bean (Vigna rabiata (Linn.) Wilczek), alfalfa (Medicago sativaL.), slash p... A field experiment was conducted to study the effects of Pb, Cd, Cu, Zn and As coexisting in red soilon growth of rice (Oryza sativa L.), mung bean (Vigna rabiata (Linn.) Wilczek), alfalfa (Medicago sativaL.), slash pine (Pinus elliottii Engelm.) and aspen (Populus L.). Results showed that rice, mung bean andalfalfa were significantly innuenced by combined pollution of the heavy metals. The contents of Pb, cd andAs in rice grains greatly exceeded the National Standards for Food Hygiene of China. Heavy metals at ahigh concentration seriously retarded growth of mung bean and alfalfa, but not so obviously with slash pineand aspen. The composite index is suggested for evaluating the relativity of combined pollution witll heavymetals in soil. 展开更多
关键词 combined pollution composite pollution index plant growth red soil
下载PDF
Transmission Dynamics of an Outbreak of the COVID-19 Delta Variant B.1.617.2——Guangdong Province,China,May-June 2021 被引量:59
6
作者 Meng Zhang Jianpeng Xiao +22 位作者 Aiping Deng Yingtao Zhang Yali Zhuang Ting Hu Jiansen Li Hongwei tu Bosheng Li Yan Zhou Jun Yuan Lei Luo Zimian Liang Youzhi Huang Guoqiang Ye Mingwei Cai Gongli Li Bo Yang Bin Xu Ximing Huang Yazun Cui Dongsheng Ren Yanping Zhang Min Kang Yan Li 《China CDC weekly》 2021年第27期584-586,共3页
On May 21,2021,a local case of coronavirus disease 2019(COVID-19)was confirmed in a 75-year-old woman(experienced onset of symptoms on May 18)in Liwan District,Guangzhou City,Guangdong Province,China.The number of inf... On May 21,2021,a local case of coronavirus disease 2019(COVID-19)was confirmed in a 75-year-old woman(experienced onset of symptoms on May 18)in Liwan District,Guangzhou City,Guangdong Province,China.The number of infections has increased in the following 10 days and led to 5 generations of transmission. 展开更多
关键词 GUANGDONG FIR BREAK
原文传递
慢性炎症、肿瘤微环境与癌变 被引量:55
7
作者 Tamas A. Gonda Shuiping tu +3 位作者 Timothy C. Wang 丁燕(翻译) 南娟(翻译) 刘谦(校对) 《中国肺癌杂志》 CAS 2009年第9期1022-1031,共10页
某些肿瘤发生前或发生时常有慢性炎症。抗炎疗法在癌症的预防及治疗中也显现出一定的疗效。创伤愈合演变为癌症前兆的具体机理已成为当前研究的热点。已有研究证实,炎症介质、炎症相关基因多态性与癌变之间存在病原学关系。潜在的炎症... 某些肿瘤发生前或发生时常有慢性炎症。抗炎疗法在癌症的预防及治疗中也显现出一定的疗效。创伤愈合演变为癌症前兆的具体机理已成为当前研究的热点。已有研究证实,炎症介质、炎症相关基因多态性与癌变之间存在病原学关系。潜在的炎症过程可通过不同的机理影响肿瘤间室与癌症分期, 展开更多
关键词 慢性炎症 肿瘤微环境 骨髓源细胞 胃癌 肌成纤维细胞 髓源性抑制细胞
下载PDF
Drift and deposition of ultra-low altitude and low volume application in paddy field 被引量:46
8
作者 Xue Xinyu tu Kang +2 位作者 Qin Weicai Yubin Lan Huihui Zhang 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2014年第4期23-28,共6页
Field trials were performed to evaluate various techniques for measuring spray deposition and aerial drift during spray application to paddy field.The application of a spraying agent containing the fluorescent dye Rho... Field trials were performed to evaluate various techniques for measuring spray deposition and aerial drift during spray application to paddy field.The application of a spraying agent containing the fluorescent dye Rhodamine-B was applied by an unmanned aerial vehicle(UAV)which flew at a height of 5 m,a speed of 3 m/s,and the wind speed of 3 m/s.The results showed that because the downdraft produced by a helicopter rotor increased the penetrability of crops,there is a higher deposition on the upper layer and the under layer than the traditional spraying.The average deposition on the upper layer accounts for 28% of the total spraying,the deposition on the under layer accounts for 26% of the total spraying.The deposition on the under layer takes up 92.8% of the deposition on the upper layer.Droplets drift data showed that the drift of non-target area took up 12.9% of the total liquid spray.The 90% drifting droplets were located within a range of 8 m of the target area;the drift quantity was almost zero at a distance of 50 m away from the treated area. 展开更多
关键词 paddy field ultra-low altitude low volume UAV droplet drift DEPOSITION
原文传递
Mapping essential urban land use categories in China(EULUC-China):preliminary results for 2018 被引量:46
9
作者 Peng Gong Bin Chen +67 位作者 Xuecao Li Han Liu Jie Wang Yuqi Bai Jingming Chen Xi Chen Lei Fang Shuailong Feng Yongjiu Feng Yali Gong Hao Gu Huabing Huang Xiaochun Huang Hongzan Jiao Yingdong Kang Guangbin Lei Ainong Li Xiaoting Li Xun Li Yuechen Li Zhilin Li Zhongde Li Chong Liu Chunxia Liu Maochou Liu Shuguang Liu Wanliu Mao Changhong Miao Hao Ni Qisheng Pan Shuhua Qi Zhehao Ren Zhuoran Shan Shaoqing Shen Minjun Shi Yimeng Song Mo Su Hoi Ping Suen Bo Sun Fangdi Sun Jian Sun Lin Sun Wenyao Sun Tian Tian Xiaohua Tong Yihsing Tseng Ying tu Hong Wang Lan Wang Xi Wan Zongming Wang Tinghai Wu Yaowen Xie Jian Yang Jun Yang Man Yuan Wenze Yue Hongda Zeng Kuo Zhang Neng Zhang Tao Zhang Yu Zhang Feng Zhao Yichen Zheng Qiming Zhou Nicholas Clinton Zhiliang Zhu Bing Xu 《Science Bulletin》 SCIE EI CAS CSCD 2020年第3期182-187,共6页
Land use reflects human activities on land.Urban land use is the highest level human alteration on Earth,and it is rapidly changing due to population increase and urbanization.Urban areas have widespread effects on lo... Land use reflects human activities on land.Urban land use is the highest level human alteration on Earth,and it is rapidly changing due to population increase and urbanization.Urban areas have widespread effects on local hydrology,climate,biodiversity,and food production[1,2].However,maps,that contain knowledge on the distribution,pattern and composition of various land use types in urban areas,are limited to city level.The mapping standard on data sources,methods,land use classification schemes varies from city to city,due to differences in financial input and skills of mapping personnel.To address various national and global environmental challenges caused by urbanization,it is important to have urban land uses at the national and global scales that are derived from the same or consistent data sources with the same or compatible classification systems and mapping methods.This is because,only with urban land use maps produced with similar criteria,consistent environmental policies can be made,and action efforts can be compared and assessed for large scale environmental administration.However,despite of the fact that a number of urban-extent maps exist at global scales[3,4],more detailed urban land use maps do not exist at the same scale.Even at big country or regional levels such as for the United States,China and European Union,consistent land use mapping efforts are rare[5,6](e.g.,https://sdi4apps.eu/open_land_use/). 展开更多
关键词 EULUC-China 土地利用类型
原文传递
Induction of apoptosis by arsenic trioxide and hydroxycamptothecin in gastric cancer cells in vitro 被引量:43
10
作者 tu SP Zhong J +4 位作者 Tan JH Jiang XH Qiao MM Wu YX Jiang SH 《World Journal of Gastroenterology》 SCIE CAS CSCD 2000年第4期532-539,共8页
AIM To study the effects of arsenic trioxide andHCPT on different degrees of differentiated gastriccancer cells(SGC-7901,MKN-45,MKN-28)withrespect to both cytotoxicity and induction ofapoptosis in vitro.METHODS The ... AIM To study the effects of arsenic trioxide andHCPT on different degrees of differentiated gastriccancer cells(SGC-7901,MKN-45,MKN-28)withrespect to both cytotoxicity and induction ofapoptosis in vitro.METHODS The cytotoxicity of As<sub>2</sub>O<sub>3</sub> and HCPTon gastric cancer cells was determined by MTTassay.Morphologic changes of apoptosis ofgastric cancer cells were observed by lightmicroscopy and transmission electron microscopy.Apoptosis and cell cycle changes of gastric cancercells induced by HCPT and As<sub>2</sub>O<sub>3</sub> were investigatedby TUNEL method and flow cytometry.RESULTS As<sub>2</sub>O<sub>3</sub> and HCPT had remarkablecytotoxic effects on different degrees ofdifferentiated gastric cancer cells.The IC<sub>50</sub>ofAs<sub>2</sub>O<sub>3</sub> on well differentiated gastric cancer cellMKN-28,moderately differentiated gastric cancercell SGC-7901,and poorly differentiated gastriccancer cell MKN-28 were 8.91 μmol/L,10.57μmol/L,and 11.65 μmol/L,respectively.The IC<sub>50</sub>of HCPT on MKN-28,SGC-7901,and MKN-45 were9.35 mg/L,10.21 mg/L,and 12.63 mg/Lrespectively after 48 h treatment.After 12 h ofexposure to both drugs,gastric cancer cellsexhibited morphologic features of apoptosis,including cell shrinkage,nuclear condensation, and formation of apoptotic bodies.A typicalsubdiploid peak before G<sub>0</sub>/G<sub>1</sub> phase was observedby flow cytometry.The apoptotic rates of SGC-7901,MKN-45,and MKN-28 were 13.84%,22.52%,and 9.68%,respectively after 48 hexposure to 10 μmol/L As<sub>2</sub>O<sub>3</sub>.The apoptotic ratesof SGC-7901,MKN-45,and MKN-28 were 21.88%,12.35%,and 30.26%,respectively after 48 hexposure to 10 mg/L HCPT.The apoptotic indicewere 7%-15% as assessed by TUNEL method.The effect of As<sub>2</sub>O<sub>3</sub> on SGC-7901 showedremarkable cell cycle specificity,which inducedcell death in G<sub>1</sub> phase,and blocked G<sub>2</sub>/M phase.HCPT also showed a remarkable cell cyclespecificity,by inducing cell death and apoptosis inG<sub>1</sub> phase and arres 展开更多
关键词 GASTRIC cancer APOPTOSIS ARSENIC TRIOXIDE HYDROXYCAMPTOTHECIN
下载PDF
Screening for main components associated with the idiosyncratic hepatotoxicity of a tonic herb, Polygonum multiflorum 被引量:44
11
作者 Chunyu Li Ming Niu +16 位作者 Zhaofang Bai Congen Zhang Yanling Zhao Ruiyu Li Can tu Huifang Li Jing Jing Yakun Meng Zhijie Ma Wuwen Feng Jinfa Tang Yun Zhu Jinjie Li Xiaoya Shang Zhengsheng Zou Xiaohe Xiao Jiabo Wang 《Frontiers of Medicine》 SCIE CAS CSCD 2017年第2期253-265,共13页
The main constituents of a typical medicinal herb, Polygonum multiflorum (Heshouwu in Chinese), that induces idiosyncratic liver injury remain unclear. Our previous work has shown that cotreatment with a nontoxic do... The main constituents of a typical medicinal herb, Polygonum multiflorum (Heshouwu in Chinese), that induces idiosyncratic liver injury remain unclear. Our previous work has shown that cotreatment with a nontoxic dose of lipopolysaccharide (LPS) and therapeutic dose of Heshouwu can induce liver injury in rats, whereas the solo treatment cannot induce observable injury. In the present work, using the constituent "knock-out" and "knock-in" strategy, we found that the ethyl acetate (EA) extract of Heshouwu displayed comparable idiosyncratic hepatotoxicity to the whole extract in LPS-treated rats. Results indicated a significant elevation of plasma alanine aminotransferase, aspartate aminotransferase, and liver histologic changes, whereas other separated fractions failed to induce liver injury. The mixture of EA extract with other separated fractions induced comparable idiosyncratic hepatotoxicity to the whole extract in LPS-treated rats. Chemical analysis further revealed that 2,3,5,4'-tetrahydroxy trans-stilbene-2-O-p-glucoside (trans-SG) and its cis-isomer were the two major compounds in EA extract. Furthermore, the isolated cis-, and not its trans-isomer, displayed comparable idiosyncratic hepatotoxicity to EA extract in LPS-treated rats. Higher contents of cis-SG were detected in Heshouwu liquor or preparations from actual liver intoxication patients associated with Heshouwu compared with general collected samples. In addition, plasma metabolomics analysis showed that cis-SG-disturbing enriched pathways remarkably differed from trans-SG ones in LPS-treated rats. All these results suggested that cis-SG was closely associated with the idiosyncratic hepatotoxicity of Heshouwu. Considering that the cis-trans isomerization oftrans- SG was mediated by ultraviolet light or sunlight, our findings serve as reference for controlling photoisomerization in drug discovery and for the clinical use of Heshouwu and stilbene-related medications. 展开更多
关键词 Polygonum multiflorum idiosyncratic hepatotoxicity metabolomics STILBENE cis-trans isomerization
原文传递
Rural restructuring in China: Theory, approaches and research prospect 被引量:41
12
作者 tu Shuangshuang LONG Hualou 《Journal of Geographical Sciences》 SCIE CSCD 2017年第10期1169-1184,共16页
Rural restructuring is a process of reshaping socio-economic morphology and spatial pattern in rural territory in response to the changes of elements both in kernel system and external system of rural development, by ... Rural restructuring is a process of reshaping socio-economic morphology and spatial pattern in rural territory in response to the changes of elements both in kernel system and external system of rural development, by optimally allocating and efficiently managing the material and non-material elements in the two systems. It aims at ultimately optimizing the structure and promoting the function within rural territorial system as well as realizing the coordination of structure and complementation of function between urban and rural territorial system. This paper establishes a theoretical framework of rural restructuring through elabo- rating the concept and connotations as well as analyzing the mechanism pushing forward rural restructuring based on the evolution of "elements-structure-function", and probes the approaches from the three aspects of spatial restructuring, economic restructuring and social restructuring. Besides, the authors argue that the study of rural restructuring in China in the future needs to focus on the aspects of long-term and multi-scale process and pattern, mechanism, regional models, rural planning technology system and standard, policy and institutional innovations concerning rural restructuring as well as the impacts of globalization on rural restructuring, in order to serve the current national strategic demands and cope with the changes of rural development elements in the process of urban-rural development transformation. 展开更多
关键词 rural restructuring rural development transformation rural territorial system elements-structurefunction spatial restructuring economic restructuring social restructuring rural geography
原文传递
Bt水稻对飞虱和叶蝉及其卵寄生蜂扩散规律的影响 被引量:30
13
作者 陈茂 叶恭银 +2 位作者 胡萃 tu J Datta S K 《浙江大学学报(农业与生命科学版)》 CAS CSCD 北大核心 2003年第1期29-33,共5页
研究了Bt水稻两个纯合品系TT9-3和TT9-4在田间对飞虱、叶蝉及其卵寄生蜂扩散规律的影响。结果表明:在Bt稻区与对照(IR72)区间相互扩散的飞虱有白背飞虱(Sogatellafurcifea)、褐飞虱(Nilaparvatalugens);叶蝉有黑尾叶蝉(Nephotetixcincti... 研究了Bt水稻两个纯合品系TT9-3和TT9-4在田间对飞虱、叶蝉及其卵寄生蜂扩散规律的影响。结果表明:在Bt稻区与对照(IR72)区间相互扩散的飞虱有白背飞虱(Sogatellafurcifea)、褐飞虱(Nilaparvatalugens);叶蝉有黑尾叶蝉(Nephotetixcincticeps)、白翅叶蝉(Erythroneurasubrufa)和电光叶蝉(Deltpcephalusdorsalis);其中以白背飞虱和黑尾叶蝉为主。扩散数量叶蝉多于飞虱;扩散方向以Bt稻区向对照区扩散为主,其中TT9-3与IR72、TT9-4与IR72间白背飞虱与黑尾叶蝉的扩散量差异均达显著水平(P<0.05)。在Bt稻区与对照区间相互扩散的飞虱和叶蝉的卵寄生蜂有稻虱缨小蜂(Anagrusspp.)和叶蝉柄翅小蜂(Lynaenonlongicrus),数量上后者多于前者,扩散方向也以Bt稻区向对照区扩散为主。 展开更多
关键词 扩散规律 BT水稻 飞虱 叶蝉 卵寄生蜂 转基因作物 生态安全
下载PDF
Rural vitalization in China:A perspective of land consolidation 被引量:40
14
作者 LONG Hualou ZHANG Yingnan tu Shuangshuang 《Journal of Geographical Sciences》 SCIE CSCD 2019年第4期517-530,共14页
The core objective of rural vitalization is to systemically establish a coupling pattern of various rural development elements including population, land and industry. As one of the prerequisites, land resources is re... The core objective of rural vitalization is to systemically establish a coupling pattern of various rural development elements including population, land and industry. As one of the prerequisites, land resources is required to be optimally allocated via land consolidation. Consequently, land consolidation contributes greatly to population agglomeration, industrial development and resources support under the context of combating rural decline. Based on the key elements affecting rural development, this paper elaborates the connotation of rural vitalization and land consolidation in the new era as well as their relationships. Furthermore, the paper analyzes the alternative paths for achieving rural vitalization via land consolidation, and discusses the future directions of land consolidation and rural vitalization. The conclusions are drawn as follows:(1) To cope with the loss and decline of the intrinsic elements in rural areas, rural vitalization is a development strategy aimed at realizing economic, political, cultural and ecological rejuvenation in rural area by reshaping socio-economic morphology and spatial pattern in rural territory.(2) From the perspective of rural vitalization, land consolidation is endowed with new connotation, which should not only target at activating the key elements of rural development, but also place emphasis on coordinating material space and spirit core as well as integrating the restructuring of the physical space and the rural governance system.(3) Land consolidation should be compatible with regional natural conditions and the current stage of socio-economic development. According to the principle of regional planning and classification strategy, the appropriate models and paths should be adopted to promote the benign interactions of population, land and industry based on engineering techniques and ecological means.(4) Under the background of national strategy of rural vitalization, it is necessary to reshape the value orientation of land consolidation based on a scientific und 展开更多
关键词 RURAL TRANSFORMATION DEVELOPMENT RURAL vitalization LAND CONSOLIDATION LAND use transition DEVELOPMENT elements REGIONAL mode
原文传递
Definition, theory, methods, and applications of the safe and efficient simultaneous extraction of coal and gas 被引量:36
15
作者 Yuanping Cheng Liang Wang +3 位作者 Hongyong Liu Shengli Kong Jintuo Zhu Qingyi tu 《International Journal of Coal Science & Technology》 EI 2015年第1期52-65,共14页
Simultaneous extraction of the coal and gas is an effective method of eliminating coal mine gas disasters while safely exploiting the coal and achieving efficient gas drainage in China, which is widely accepted by the... Simultaneous extraction of the coal and gas is an effective method of eliminating coal mine gas disasters while safely exploiting the coal and achieving efficient gas drainage in China, which is widely accepted by the main coal-producing countries around the world. However, the concrete definition of simultaneous extraction is vague and there is little accurate theoretical support for the simultaneous extraction of coal and gas, which makes it difficult to determine an efficient gas drainage method appropriate to the features of coal seams. Based on theoretical analysis, laboratory tests and field observations, a specific definition of simultaneous extraction of coal and gas is proposed after analyzing the characteristics of coal seam occurrences in China, and we developed the mechanism of mining-enhanced permeability and established the corresponding theoretical model. This comprises a process of fracture network formation, in which the original fractures are opened and new fractures are produced by unloading damage. According to the theoretical model, the engineering approaches and their quantitative parameters of 'unloading by borehole drilling' for single coal seams and 'unloading by protective seam mining' for groups of coal seams are proposed, and the construction principles for coal exploitation and gas-drainage systems for different conditions are given. These methods were applied successfully in the Tunlan Coal Mine in Shanxi Province and the Panyi Coal Mine in Anhui Province and could assure safe and efficient simultaneous extraction of coal and gas in these outburst coal mines. 展开更多
关键词 Coal seam gas Outburst coal seam Mining-enhanced permeability Simultaneous extraction of coal and gas
下载PDF
Alpine wetlands in the Lhasa River Basin, China 被引量:35
16
作者 ZHANG Yili WANG Chunlian +3 位作者 BAI Wanqi WANG Zhaofeng tu Yanli YANGJAEN Dor Gka 《Journal of Geographical Sciences》 SCIE CSCD 2010年第3期375-388,共14页
The Lhasa River Basin is one of the typical distribution regions of alpine wetlands on the Tibetan Plateau. It is very important to get a better understanding of the background and characteristics of alpine wetland fo... The Lhasa River Basin is one of the typical distribution regions of alpine wetlands on the Tibetan Plateau. It is very important to get a better understanding of the background and characteristics of alpine wetland for monitoring, protection and utilization. Wetland construction and distribution in the basin were analyzed based on multi-source data including field investigation data, CBERS remote sensing data and other thematic data provided by 3S technology. The results are (1) the total area of wetlands is 209,322.26 hm^2, accounting for 6.37% of the total land area of the basin. The wetlands are mainly dominated by natural wetland, with artificial wetland occupying only 1.09% of the wetland area; marsh wetland is the principal part of natural wetland, dominated by Kobresia littledalei swampy meadow which is distributed in the river source area and upstream of Chali, Damshung and Medro Gongkar counties. The ratio and type of wetlands in different counties differ significantly, which are widely distributed in Chali and Damshung counties (accounting for 62% of the total wetland area). (2) The concentrated vertical distribution of wetlands is at an elevation of 3600-5100 m The wetlands are widely distributed throughout the Yarlung Zangbo River Valley from river source to river mouth into the Yarlung Zangbo River. Marsh wetland is dominant in the source area and upstream of the river, with the mosaic distribution of lakes, Kobresia litUedalei and Carex moorcroftii swampy meadow, shrubby swamp and river; as for the middle-down streams, the primary types are river wetland and flooded wetland. The distribution is in a mosaic pattern of river, Kobresia humilis and Carex moorcroftii swampy meadow, Phragmites australis and subordinate grass marsh, flooded wetland and artificial wetland. 展开更多
关键词 Lhasa River Basin alpine wetland classification system DISTRIBUTION 3S technology
下载PDF
Responses of Soil Microbial Community Structure and Diversity to Agricultural Deintensification 被引量:29
17
作者 ZHANG Wei- Jian RUI Wen-Yi +7 位作者 C. tu H. G. DIAB F. J. LOUWS J. P. MUELLER N. CREAMER M. BELL M.G. WAGGER S. HU 《Pedosphere》 SCIE CAS CSCD 2005年第4期440-447,共8页
Using a scheme of agricultural fields with progressively less intensive management (deintensification), different manage- ment practices in six agroecosystems located near Goldsboro, NC, USA were tested in a large-sca... Using a scheme of agricultural fields with progressively less intensive management (deintensification), different manage- ment practices in six agroecosystems located near Goldsboro, NC, USA were tested in a large-scale experiment, including two cash-grain cropping systems employing either tillage (CT) or no-tillage (NT), an organic farming system (OR), an integrated cropping system with animals (IN), a successional field (SU), and a plantation woodlot (WO). Microbial phos- pholipid fatty acid (PLFA) profiles and substrate utilization patterns (BIOLOG ECO plates) were measured to examine the effects of deintensification on the structure and diversity of soil microbial communities. Principle component analyses of PLFA and BIOLOG data showed that the microbial community structure diverged among the soils of the six systems. Lower microbial diversity was found in lowly managed ecosystem than that in intensive and moderately managed agro- ecosystems, and both fungal contribution to the total identified PLFAs and the ratio of microbial biomass C/N increased along with agricultural deintensification. Significantly higher ratios of C/N (P < 0.05) were found in the WO and SU systems, and for fungal/bacterial PLFAs in the WO system (P < 0.05). There were also significant decreases (P < 0.05) along with agricultural deintensification for contributions of total bacterial and gram positive (G+) bacterial PLFAs. Agricultural deintensification could facilitate the development of microbial communities that favor soil fungi over bacteria. 展开更多
关键词 agricultural deintensification AGROECOSYSTEMS carbon retention soil microbial community
下载PDF
Semi-Supervised Learning with Generative Adversarial Networks on Digital Signal Modulation Classification 被引量:34
18
作者 Ya tu Yun Lin +1 位作者 Jin Wang Jeong-Uk Kim 《Computers, Materials & Continua》 SCIE EI 2018年第5期243-254,共12页
Deep Learning(DL)is such a powerful tool that we have seen tremendous success in areas such as Computer Vision,Speech Recognition,and Natural Language Processing.Since Automated Modulation Classification(AMC)is an imp... Deep Learning(DL)is such a powerful tool that we have seen tremendous success in areas such as Computer Vision,Speech Recognition,and Natural Language Processing.Since Automated Modulation Classification(AMC)is an important part in Cognitive Radio Networks,we try to explore its potential in solving signal modulation recognition problem.It cannot be overlooked that DL model is a complex model,thus making them prone to over-fitting.DL model requires many training data to combat with over-fitting,but adding high quality labels to training data manually is not always cheap and accessible,especially in real-time system,which may counter unprecedented data in dataset.Semi-supervised Learning is a way to exploit unlabeled data effectively to reduce over-fitting in DL.In this paper,we extend Generative Adversarial Networks(GANs)to the semi-supervised learning will show it is a method can be used to create a more dataefficient classifier. 展开更多
关键词 Deep Learning automated modulation classification semi-supervised learning generative adversarial networks
下载PDF
Aftershock sequence relocation of the 2021 M_(S)7.4 Maduo Earthquake, Qinghai, China 被引量:34
19
作者 Weilai WANG Lihua FANG +4 位作者 Jianping WU Hongwei tu Liyi CHEN Guijuan LAI Long ZHANG 《Science China Earth Sciences》 SCIE EI CSCD 2021年第8期1371-1380,共10页
The 2021 Qinghai Maduo M_(S)7.4 earthquake was one of the strongest earthquakes that occurred in the Bayan Har block of the Tibetan Plateau during the past 30 years,which spatially filled in the gap of strong earthqua... The 2021 Qinghai Maduo M_(S)7.4 earthquake was one of the strongest earthquakes that occurred in the Bayan Har block of the Tibetan Plateau during the past 30 years,which spatially filled in the gap of strong earthquake in the eastern section of the northern block boundary.In this study,the aftershock sequence within 8 days after the mainshock was relocated by double difference algorithm.The results show that the total length of the aftershock zone is approximately 170 km;the mainshock epicenter is located in the center of the aftershock zone,indicating a bilateral rupture.The aftershocks are mainly distributed along NWW direction with an overall strike of 285°.The focal depth profiles indicate that the seismogenic fault is nearly vertical and dips to southwest or northeast in different sections,indicating a complex geometry.There is an aftershock gap located to the southeast of the mainshock epicenter with a scale of approximately 20 km.At the eastern end of the aftershock zone,horsetaillike branch faults show the terminal effect of a large strike-slip fault.There is a NW-trending aftershock zone on the north side of the western section,which may be a branch fault triggered by the mainshock.The location of the aftershock sequence is close to the eastern section of the Kunlun Mountain Pass-Jiangcuo(KMPJ)fault.The sequence overlaps well with surface trace of the KMPJ fault.We speculate that the KMPJ fault is the main seismogenic fault of the M_(S)7.4 Maduo earthquake. 展开更多
关键词 Maduo earthquake Aftershock sequence Double-difference location Kunlun Mountain Pass-Jiangcuo fault
原文传递
福建省社区产后访视质量调查研究 被引量:33
20
作者 陈起燕 陈烈平 +5 位作者 张荣莲 叶宝凤 翁云钦 卓秀云 Yu liana Da tu Bua 《中国妇幼保健》 CAS 北大核心 2005年第5期534-535,共2页
目的:研究社区产后访视服务现状,提高社区护理质量,促进母婴健康.方法:定量与定性研究相结合,定量研究随机抽取福州市5区内产后42 d左右的产妇776例问卷调查,定性研究采用专题小组讨论和半结构性访谈.产妇12人参加专题讨论,半结构性访谈... 目的:研究社区产后访视服务现状,提高社区护理质量,促进母婴健康.方法:定量与定性研究相结合,定量研究随机抽取福州市5区内产后42 d左右的产妇776例问卷调查,定性研究采用专题小组讨论和半结构性访谈.产妇12人参加专题讨论,半结构性访谈9人.结果:产后访视率为62.9%,按3~4次标准进行的仅4.3%~48.2%.社区产后访视内容中,询问母子一般情况达98.4%;对产妇及新生儿体检的内容欠缺多;进行母乳喂养指导为94.7%;认为对产妇心理情绪状况'关心与非常关心'的占28.7%,对预防产后抑郁症的保健建议率占9.9%;对社区产后访视满意率不高为33.6%.结论:与产后访视的次数和内容的标准对照,实际操作中的偏差是由于缺乏规范化的管理,因此今后既要加快产后访视人员刘产褥期护理与保健知识的更新,拓展提供保健知识的内容,又要在现有社区产后访视过程中,加强规范化管理,区级妇幼保健机构应对辖区内的社区产妇的产后访视工作实行面对面的质量评估问卷,达到规范化管理的目的,并采取针对性措施提高产后访视中的护理与保健质量. 展开更多
关键词 社区 产后访视 护理与保健质量
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部