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Search Results: 1 - 10 of 127049 matches for " LI Zhenxi "
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Can China''s Sci-tech Journals Make Breakthrough in View of Innovative Commercial Model of World Journal of Gastroenterology (WJG) ?
从WJG创新商业模式看中国科技期刊的“突围”

LI ZhenXi,
李镇西

中国科技期刊研究 , 2008,
Abstract: 打造中国的国际一流科技期刊已成为全社会的共识与面临的紧迫任务。本文基于World Journal of Gastroenterology(WJG)的案例分析,认为WJG 创刊14年来,遵从新经济规律,创新商业模式,采取了“开放存取的办刊宗旨、以快制胜的竞争策略、全球化的资源配置、有利于产业升级的‘价值链’、市场导向的经营模式、与现代管理接轨的‘流程’”等一系列“突围”措施,从而实现了“读者价值最大化、作者价值最大化、社会价值最大化”的发展目标,现已成为胃肠病学和肝病学领域唯一一个国际性的、以周刊出版的同行评议性期刊。本文以“WJG模式”为案例,研究中国科技期刊的“国际化战略”,强调必须树立新经济时代的办刊理念,把创新商业模式作为期刊“突围”的切入点与突破口,并建议科技期刊界学习和借鉴中国经济腾飞的经验,在期刊市场化建设与多元化模式上迈出更大的改革步伐。
TheCompositionandDistributionofSomeKindsofAnaerobicMicroorganismsintheQuaternaryDepositsofEastinQaidamBasin
Shen,Jianzhong,Li,Zhenxi,Ji,Meiying,Lou,Hong
沉积学报 , 1996,
Abstract: Underthestrictlyanaerobicconditions,thequantitiesof,sulfatereducingbacteria,fermentativebacteris,cellulolyticbacteriaandmethanogenicbacteriaofserialgeologicalquaiernarysamplesgotfromanerectsectionofeastinQaidambasin.Themorphologyofdifferentkindsofbacteriawereobservedandthemetabolictypeofmethanogenicbacteriawereobserved.Theresultshowthattheprocessofreducingsulfateendedandthemethanogenicprocessbegan.Thedistributionsoffermentativebacteriaandcellulolyticbacteriaaretandom,theyhavenorelationshipwiththecontentoforganicmatterandcellulose.Themorphologyofbacteriaindifferentsamplesaredifferent.Themethanogenicbacteriaonlypresentinpartofsamples.AllofthemethanogenicbacteriabelongtothepopulationofMethanobacteriumandthetypeofnutrimentisH2/CO2.
Strong/Weak Summer Monsoon Activity over the South China Sea and Atmospheric Intraseasonal Oscillation
强弱南海夏季风活动及大气季节内振荡

Li Chongyin,Long Zhenxia,Zhang Qingyun,
Li Chongyin
,Long Zhenxi,Zhang Qingyun

大气科学进展 , 2001,
Abstract: The circulation pattern corresponding to the strong / weak summer monsoon in the South China Sea (SCS) region and the associated characteristics of the abnormal rainfall in Eastern China have been studied by using the NECP reanalysis data and precipitation data in China. The results show that the climate variations in China caused by the strong/weak summer monsoon are completely different (even in opposite phase). The analyses of atmospheric intraseasonal oscillation (ISO) activity showed that the atmospheric ISO at 850 hPa near the SCS region is strong (weak) corresponding to the strong (weak) SCS summer monsoon. And the analyses of the circulation pattern of the atmospheric ISO showed that the strong / weak SCS summer monsoon circulation (200 hPa and 850 hPa) result mainly from abnormal atmospheric ISO.This study also reveals that the atmospheric ISO variability in the South China Sea region is usually at opposite phase with one in the Jiang-huai River basin. For example, strong (weak) atmospheric ISO in the SCS region corresponds to the weak (strong) atmospheric ISO in the Jiang-huai River basin. As to the intensity of atmospheric ISO, it is generally exhibits the local exciting characteristics, the longitudinal propagation is weak.
Changes in individual plant traits and biomass allocation in alpine meadow with elevation variation on the Qinghai-Tibetan Plateau
WeiLing Ma,PeiLi Shi,WenHua Li,YongTao He,XianZhou Zhang,ZhenXi Shen,SiYue Chai
Science China Life Sciences , 2010, DOI: 10.1007/s11427-010-4054-9
Abstract: Plant traits and individual plant biomass allocation of 57 perennial herbaceous species, belonging to three common functional groups (forbs, grasses and sedges) at subalpine (3700 m ASL), alpine (4300 m ASL) and subnival ( 5000 m ASL) sites were examined to test the hypothesis that at high altitudes, plants reduce the proportion of aboveground parts and allocate more biomass to belowground parts, especially storage organs, as altitude increases, so as to geminate and resist environmental stress. However, results indicate that some divergence in biomass allocation exists among organs. With increasing altitude, the mean fractions of total biomass allocated to aboveground parts decreased. The mean fractions of total biomass allocation to storage organs at the subalpine site (7%±2% S.E.) were distinct from those at the alpine (23%±6%) and subnival (21%±6%) sites, while the proportions of green leaves at all altitudes remained almost constant. At 4300 m and 5000 m, the mean fractions of flower stems decreased by 45% and 41%, respectively, while fine roots increased by 86% and 102%, respectively. Specific leaf areas and leaf areas of forbs and grasses deceased with rising elevation, while sedges showed opposite trends. For all three functional groups, leaf area ratio and leaf area root mass ratio decreased, while fine root biomass increased at higher altitudes. Biomass allocation patterns of alpine plants were characterized by a reduction in aboveground reproductive organs and enlargement of fine roots, while the proportion of leaves remained stable. It was beneficial for high altitude plants to compensate carbon gain and nutrient uptake under low temperature and limited nutrients by stabilizing biomass investment to photosynthetic structures and increasing the absorption surface area of fine roots. In contrast to forbs and grasses that had high mycorrhizal infection, sedges had higher single leaf area and more root fraction, especially fine roots.
Theoretic Analysis and calculation on Optical-thermal Effect in PDT
光动力治疗中热效应的理论分析与计算

Li Zhongming,Zhang Zhenxi,
李忠明
,张镇西

光子学报 , 2006,
Abstract: Temperature distribution in the bio-tissue during PDT is theoretical analyzed based on the Pennes' bio-heat transfer equations. The study indicated that Laser heat source can be formed in bio-tissue during laser irradiation which result in temperature rising in one-dimensional space. The temperature in biological tissue increases in exponent with time and decreases in exponent with the distance from laser irradiation area. There is minimal light dosage threshold during the optical-thermal interaction between laser and biological tissue. When light dosage below the critical threshold,laser irradiating will not produce thermal effect. The threshold,which depends on optical parameter and heat parameter of biotissue,increases in exponent with the distance from laser irradiating area.
Dynamic Analysis for Optical Tweezers Upon Cells as Microsphere Model
球模型生物细胞在光镊势阱中的动力学分析

Yu Youli,Zhang Zhenxi,Li Zheng,
喻有理
,张镇西,李政

光子学报 , 2005,
Abstract: 用动力学方法求出了球模型生物细胞在光阱中的横向位移均方差与时间的关系.结果表明:小球在光阱中服从Boltzman分布,两种方法可用于直接对细胞光阱力标定;细胞位移幅度典型值为纳米量级,定标系统的空间分辨率为纳米量级.结论和已有实验结果相符.
Characteristics of grassland degradation and driving forces in the source region of the Yellow River from 1985 to 2000*

LIU Linshan,ZHANG Yili,BAI Wanqi,YAN Jianzhong,DING Mingjun,SHEN Zhenxi,LI Shuangcheng,

地理学报 , 2006,
Abstract: The source region of the Yellow River is located in the middle east of the Tibetan Plateau in northwest China. The total area is about 51,700 km2, mainly covered by grassland (79%), unused land (16%) and water (4%). The increasing land utilization in this area has increased the risk of environmental degradation. The land use/cover data (1985 and 2000) provided by the Data Center of Resources and Environment in the Chinese Academy of Sciences were used to analyze the land cover change in the source region of the Yellow River. DEM (1:250,000) data, roads and settlement data were used to analyze the spatial characteristics of grasslands degradation. The ArcGIS 9 software was used to convert data types and do the overlay, reclassification and zonal statistic analysis. Results show that grassland degradation is the most important land cover change in the study area, which occupied 8.24% of the region’s total area. Human activities are the main causes of the grassland degradation in the source region of the Yellow River: 1) the degradation rate is higher on the sunny slope than on the shady slope; 2) the grassland degradation rate decreases with an increase in the elevation, and it has a correlation coefficient of -0.93; 3) the nearer to the settlements the grassland is, the higher the degradation rate. Especially within a distance range of 12 km to the settlements, the grassland degradation rate is highly related with the distance, with a coefficient of -0.99; and 4) in the range of 4 km, the degradation rate decreases with the increase of distance to the roads, with a correlation coefficient of -0.98. Besides some physical factors, human activities have been the most important driving forces of the grassland degradation in the source region of the Yellow River since 1985. To resolve the degradation problems, population control is essential, and therefore, it can reduce the social demand of livestock products from the grassland. To achieve sustainable development, it needs to improve the management of grassland ecosystem.
Fuzzy cluster analysis of the provenance of ancient Yaozhou porcelain body
Guoxia Li,Weijuan Zhao,Rongwu Li,Jianzhong Xie,Songlin Feng,Dongyu Fan,Ying Zhang,Zhifang Cai,Zhenxi Zhuo,Zhengyao Gao
Chinese Science Bulletin , 2003, DOI: 10.1007/BF03183328
Abstract: The technique of neutron activation analysis (NAA) has been employed to measure the content of 29 kinds of elements in the sample of Yaozhou porcelain bodies. Then a fuzzy cluster analysis has been conducted to the NAA data and a diagram of the dynamic fuzzy cluster analysis has been achieved. The results indicate that the batch of ancient Yaozhou porcelain bodies, which were of different overglaze color and were produced by different kilns during a period of over 800 years from the Tang Dynasty (618–907 A.D.) to the Yuan Dynasty (1271–1368 A.D.), has shared a stable and concentrated raw material source. Provenances of porcelain bodies from different times, though having their specific independence, enjoy a close relationship and are not far from one another. Provenances of porcelain bodies made during the Tang Dynasty and the Five Dynasties (907–960 A.D.) are found to be closer to one another, while those of the Song (960–1279 A.D.) and the Jin Dynasty (1115–1234 A.D.) are comparatively concentrated in certain areas and are different from those of the Tang Dynasty. Both the tri-colored glazed pottery made in Yaozhou kilns during the Tang Dynasty and the Yaozhou porcelain bodies of the Tang period are from the same provenance.
AStudyontheMiddleUpperProterozoicandLowerPalaeozoicSourceRockfromtheHuabeiAreainChina
Fan,Pu,Zhang,Baisheng,Li,Jinggui,Zhang,Qian,Li,Zhenxi,Wang,Zhaoyun,Zeng,Fangang,Cui,Mingzhong,Ma,Keyang
沉积学报 , 1996,
Abstract: TheHuabeiareainChinaiswidespreadlycoveredbyMiddleUpperProterozoicandLowerPalaeozoicmarinecarbonaterockswithseveralthousandmetersinthickness.Therearesomedifficultiesinstudyingthegeneticmechanismofhydrocarbonsinthesesourcerocksbecauseofthegenerallyhighmaturationoftheorganicmatter.ThepurposeofthepresentpaperistoevaluatewhetherornottheMiddleUpperProterozoicandLowerPalaeozoicmarinecarbonaterocksintheHuabeiareaareanimportantsuiteofhydrocarbonsourcerocksandtoprovidethepetroleumexplorationinthisareawithsomescientificdata.Thepresentpapermainlydealswiththecharacteristicsofsedimentaryenvironments,abundanceandmaturityoforganicmatter,kerogentypesandbiomarkersofthehydrocarbonsourcerockformedintheMiddleUpperProterozoicandLowerPalaeozoicstrataoftheHuabeiarea.Moreover,anevaluationonthepotentialhydrocarbongenerationofthesourcerockhasbeenmadeandfavorableareasfortheformationofthehydrocarbonsourcerockwithinthisareahavebeenpointedoutaswell.
Characteristics of grassland degradation and driving forces in the source region of the Yellow River from 1985 to 2000
黄河源地区草地退化空间特征

Linshan Liu,Yili Zhang,Wanqi Bai,Jianzhong Yan,Mingjun Ding,Zhenxi Shen,Shuangcheng Li,Du Zheng,
刘林山
,张镱锂,摆万奇,YAN Jianzhong,DING Mingjun,SHEN Zhenxi,LI Shuangcheng,ZHENG Du

地理学报(英文版) , 2006,
Abstract: The source region of the Yellow River is located in the middle east of the Tibetan Plateau in northwest China. The total area is about 51,700 km2, mainly covered by grassland (79%), unused land (16%) and water (4%). The increasing land utilization in this area has increased the risk of environmental degradation. The land use/cover data (1985 and 2000) provided by the Data Center of Resources and Environment in the Chinese Academy of Sciences were used to analyze the land cover change in the source region of the Yellow River. DEM (1:250,000) data, roads and settlement data were used to analyze the spatial characteristics of grasslands degradation. The ArcGIS 9 software was used to convert data types and do the overlay, reclassification and zonal statistic analysis. Results show that grassland degradation is the most important land cover change in the study area, which occupied 8.24% of the region’s total area. Human activities are the main causes of the grassland degradation in the source region of the Yellow River: 1) the degradation rate is higher on the sunny slope than on the shady slope; 2) the grassland degradation rate decreases with an increase in the elevation, and it has a correlation coefficient of 0.93; 3) the nearer to the settlements the grassland is, the higher the degradation rate. Especially within a distance range of 12 km to the settlements, the grassland degradation rate is highly related with the distance, with a coefficient of 0.99; and 4) in the range of 4 km, the degradation rate decreases with the increase of distance to the roads, with a correlation coefficient of 0.98. Besides some physical factors, human activities have been the most important driving forces of the grassland degradation in the source region of the Yellow River since 1985. To resolve the degradation problems, population control is essential, and therefore, it can reduce the social demand of livestock products from the grassland. To achieve sustainable development, it needs to improve the management of grassland ecosystem. Foundation: National Natural Science Foundation of China, No.90202012; National Basic Research Program of China, No.2005CB422006; No.2002CB412507; Knowledge Innovation Project of CAS, No.KZCX3-SW-339 Author: Liu Linshan, Ph.D. Candidate, specialized in land-use/land-cover change and physical geography.
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