期刊文献+
共找到848篇文章
< 1 2 43 >
每页显示 20 50 100
论网约车地方法律监管中的“区分”机制——基于功能主义的阐论 被引量:7
1
作者 高一飞 徐亚文 《浙江工商大学学报》 CSSCI 2017年第2期70-78,共9页
伴随着《网络预约出租汽车经营服务管理暂行办法》的实施,地方政府的实施细则相继出台,网约车监管已迈入"后立法时代"。网约车法律监管的关键在于通过设定网约车的准入门槛而实现与传统巡游出租车的"区分",这种区... 伴随着《网络预约出租汽车经营服务管理暂行办法》的实施,地方政府的实施细则相继出台,网约车监管已迈入"后立法时代"。网约车法律监管的关键在于通过设定网约车的准入门槛而实现与传统巡游出租车的"区分",这种区分的运行机制可以视为一种权力系统,包括中央和地方两部分,其功能实现主要体现在车辆条件、驾驶员、经营方式三个方面。整体来看,这一系统的正向功能在于整合出租车市场,但也对包括网约车平台、网约车车主、乘客在内的规制对象造成了诸多负面影响,系统本身亦需要承受来自内部要素、外部环境、其他系统的压力而展现出变迁的倾向。作为优化措施,可考虑转变规制思维、改变规制模式。 展开更多
关键词 网约车 功能主义 “区分”机制 规制
下载PDF
浅谈项目教学法在商品管理课程教学中的应用——以“区分包装类型”一节教学为例
2
作者 叶静 《国家通用语言文字教学与研究》 2023年第9期121-123,共3页
商品管理是中职院校开设的一门管理综合类课程,旨在培养实用性的管理人才。在该课程的教学过程中,项目教学法成为一种常用的教学手段,通过强调以生为本的原则,在带领学生掌握商品管理相关理论知识的同时,能够以项目实践的方式锻炼学生... 商品管理是中职院校开设的一门管理综合类课程,旨在培养实用性的管理人才。在该课程的教学过程中,项目教学法成为一种常用的教学手段,通过强调以生为本的原则,在带领学生掌握商品管理相关理论知识的同时,能够以项目实践的方式锻炼学生的应用能力,以进一步激发学生的学习积极性和主动性。对此,以商品管理课程中的“区分包装类型”一节教学为例,通过阐述项目教学法在商品管理课程教学中的应用价值,在此基础上探究项目教学法在商品管理课程教学中的应用,以期提高商品管理课程的教学质量。 展开更多
关键词 项目教学法 商品管理课程 “区分包装类型”
下载PDF
“认识”与“思想”的区分及其意义——对《纯粹理性批判》第二版序文的微观考察
3
作者 卢现军 《海南大学学报(人文社会科学版)》 2005年第3期255-257,共3页
在康德《纯粹理性批判》第二版序文的一段表述中,康德明确提到这样一个观点:认识不同于思想。正是人的“思想”这一功能,保证了物自体、本体和自由等超越经验的理念存在的可能性,也为人能够拥有一个无限的、永恒的世界提供了可能,同时... 在康德《纯粹理性批判》第二版序文的一段表述中,康德明确提到这样一个观点:认识不同于思想。正是人的“思想”这一功能,保证了物自体、本体和自由等超越经验的理念存在的可能性,也为人能够拥有一个无限的、永恒的世界提供了可能,同时也为康德对道德哲学和宗教哲学的论证提供了根基。 展开更多
关键词 康德 认识 思想 “区分”
下载PDF
Solution of idle LBO problem for high FAR aero combustor
4
作者 CHIN Jushan ZENG Qinghua 《推进技术》 EI CAS CSCD 北大核心 2024年第10期96-104,共9页
The paper sheds light on the idle lean blow off(LBO)problem for high fuel air ratio(FAR)com⁃bustor,which is impossible to be addressed with traditional aero combustor design.A significant improvement in aero combustor... The paper sheds light on the idle lean blow off(LBO)problem for high fuel air ratio(FAR)com⁃bustor,which is impossible to be addressed with traditional aero combustor design.A significant improvement in aero combustor design is required to resolve the idle LBO issue.The authors detailed a practical and efficient solu⁃tion,which not only solved the idle LBO issue but also defined the aero-thermal design for high-FAR combustor.The design will usher in a new era of aero combustor. 展开更多
关键词 Aero engine COMBUSTOR Idle lean blow off High fuel air ratio Concentric circle zoning combustion
下载PDF
Visual navigation in orchard based on multiple images at different shooting angles
5
作者 MA Zenghong YUE Jiawen +3 位作者 YIN Cheng ZHAO Runmao CHANDA Mulongoti DU Xiaoqiang 《智能化农业装备学报(中英文)》 2024年第4期51-65,共15页
The orchards usually have rough terrain,dense tree canopy and weeds.It is hard to use GNSS for autonomous navigation in orchard due to signal occlusion,multipath effect,and radio frequency interference.To achieve auto... The orchards usually have rough terrain,dense tree canopy and weeds.It is hard to use GNSS for autonomous navigation in orchard due to signal occlusion,multipath effect,and radio frequency interference.To achieve autonomous navigation in orchard,a visual navigation method based on multiple images at different shooting angles is proposed in this paper.A dynamic image capturing device is designed for camera installation and multiple images can be shot at different angles.Firstly,the obtained orchard images are classified into sky and soil detection stage.Each image is transformed to HSV space and initially segmented into sky,canopy and soil regions by median filtering and morphological processing.Secondly,the sky and soil regions are extracted by the maximum connected region algorithm,and the region edges are detected and filtered by the Canny operator.Thirdly,the navigation line in the current frame is extracted by fitting the region coordinate points.Then the dynamic weighted filtering algorithm is used to extract the navigation line for the soil and sky detection stage,respectively,and the navigation line for the sky detection stage is mirrored to the soil region.Finally,the Kalman filter algorithm is used to fuse and extract the final navigation path.The test results on 200 images show that the accuracy of visual navigation path fitting is 95.5%,and single frame image processing costs 60 ms,which meets the real-time and robustness requirements of navigation.The visual navigation experiments in Camellia oleifera orchard show that when the driving speed is 0.6 m/s,the maximum tracking offset of visual navigation in weed-free and weedy environments is 0.14 m and 0.24 m,respectively,and the RMSE is 30 mm and 55 mm,respectively. 展开更多
关键词 ORCHARD visual navigation multiple shooting angles region segmentation Kalman filter
下载PDF
马克思主义中国化研究中的“区分割裂论”驳议 被引量:4
6
作者 王刚 《江西师范大学学报(哲学社会科学版)》 CSSCI 北大核心 2021年第1期34-40,共7页
马克思主义中国化,既是中国共产党提出的一个重要政治命题,也是一个重要理论命题;既指向结合的“过程”,也指向结合的“结果”,因而具有鲜明的“二重性”。在认识这种“二重性”时,有人形成了所谓的“区分割裂论”。事实上,马克思主义... 马克思主义中国化,既是中国共产党提出的一个重要政治命题,也是一个重要理论命题;既指向结合的“过程”,也指向结合的“结果”,因而具有鲜明的“二重性”。在认识这种“二重性”时,有人形成了所谓的“区分割裂论”。事实上,马克思主义中国化是集政治性和学术性于一体的,并且政治和学术之间本来就存在某种程度的关联,二者须臾不可离分;同样,马克思主义与中国实际相结合,是马克思主义与中国实践、中国历史文化“两个结合”,而不是“一个结合”;马克思主义与中国实际相结合的“结果”也不仅仅是理论成果,它还有实践成果和制度成果,是“三个成果”的统一。 展开更多
关键词 马克思主义中国化 “二重性” “区分割裂论”
下载PDF
Physiological Adaptation of Habitat by Ion Distribution in the Leaves of Four Ecotypes of Reed (Phragmites australis) 被引量:9
7
作者 郑文菊 陈国仓 +3 位作者 张承烈 胡玉熹 李凌浩 林金星 《Acta Botanica Sinica》 CSCD 2002年第1期82-87,共6页
The ion levels in the epidermal bulliform cells of epidermis, mesophyll cells and cells of the vascular bundle sheath of four ecotypes of reed (Phragmites australis (Cav.) Trin. ex Steud.) were determined by means of ... The ion levels in the epidermal bulliform cells of epidermis, mesophyll cells and cells of the vascular bundle sheath of four ecotypes of reed (Phragmites australis (Cav.) Trin. ex Steud.) were determined by means of X_ray microanalysis. The results indicated that higher K +, Na +, Ca 2+ , Mg 2+ and Cl - were distributed in the vascular bundle sheath cells than in mesophyll cells and epidermal bulliform cells of the swamp ecotype. Higher Ca 2+ was found in the bulliform cells than in mesophyll cells and vascular bundle sheath cells, higher Mg 2+ in the mesophyll cells and higher K +, Na + and Cl - in the vascular bundle sheath cells of the dune ecotype. Higher Na + and Mg 2+ was determined in the mesophyll cells than in the bulliform cells and vascular bundle sheath cells, and higher K +, Ca 2+ and Cl - in the vascular bundle sheath cells of the light salt meadow ecotype. In the heavy salt meadow ecotype, higher Na + and Mg 2+ were accumulated in the bulliform cells than in mesophyll cells and vascular bundle sheath cells, but higher K +, Ca 2+ and Cl - in the mesophyll cells. Furthermore, the distributional conditions of the above five ions in leaf cells of the four ecotypes and their significance in the physiological adaptation of reed to habitat were discussed in detail. 展开更多
关键词 reed ( Phragmites australis ) ion distribution physiological adaptation ECOTYPES X_ray micro_analysis
下载PDF
Population genetic diversity and regional differentiation of Chinese forest frog s (Rana chensinensis) in Heilongjiang Province 被引量:6
8
作者 肖向红 郑冬 +1 位作者 李枫 刘学东 《Journal of Forestry Research》 SCIE CAS CSCD 2001年第1期40-42,共4页
The Random Amplified Polymorphism DNA (RAPD) markers were used to stu dy the intra-specific diversity and regional differentiation of the Chinese fore st frogs (Rana chensinensis), which were sampled from the fields o... The Random Amplified Polymorphism DNA (RAPD) markers were used to stu dy the intra-specific diversity and regional differentiation of the Chinese fore st frogs (Rana chensinensis), which were sampled from the fields of 8 regions in Heilongjiang Province. Totally 78 polymorphic DNA loci were amplified by 10 RAP D primers. By genetic distance analysis and phylogenetic tree reconstruction wit h the Neighbor-Joining (NJ) method the results showed that the populations of Ch inese forest frogs distributed in 8 regions existed great differentiation (Avera ge Fst=0.347, SD=0.235) while there was the paradox between geographic distances and genetic distances. Based on geographic and geological data, a hypothesis wa s posed that it is very possible that the hilly lands in the downstream of the S onghua River and the Heilong River were the center of the origin of the Chinese forest frogs in Heilongjiang Province. And mainly through the Songhua River syst em, the Chinese forest frogs dispersed into the Songneng Plain from the Sanjiang Plain whereas the Fangzheng region became a sub-center for the western dispersi on. 展开更多
关键词 Chinese forest frogs (Rana chensinensis) Population genetics Regiona l differentiation
下载PDF
Elemental Composition of the Shell of the Testate Amoeba Difflugia tuberspinifera (Sarcodina:Rhizopoda) 被引量:4
9
作者 杨军 Louis BEYENS +1 位作者 沈韫芬 冯伟松 《Zoological Research》 CAS CSCD 北大核心 2004年第5期452-455,共4页
X-ray microanalysis was used to study the elemental composition of the shell of the freshwater testate amoeba Difflugia tuberspinifera Hu et al.,1997 collected from Mulan Lake,Hubei province,China in July 2003.The res... X-ray microanalysis was used to study the elemental composition of the shell of the freshwater testate amoeba Difflugia tuberspinifera Hu et al.,1997 collected from Mulan Lake,Hubei province,China in July 2003.The results show that the shell is composed of ten elements:Si in greater quantity;then Ca and Al;and traces of K,Na,Cl,Fe,Mg,S and P.The analysis of results suggests that D.tuberspinifera in elemental composition appears to occupy a middle position between marine and soil testate amoebae. 展开更多
关键词 Testate amoebae Difflugia tuberspinifera X-ray microanalysis Elemental composition
下载PDF
Distribution of Nutrients in Arable Land Soil of Western Hainan 被引量:2
10
作者 王华 冯焕德 王荣香 《Agricultural Science & Technology》 CAS 2016年第10期2390-2393,共4页
[Objective] This study aimed to reveal distribution characteristics of soil nutrients in tropical farmland, thereby providing a reference for cropland management and balanced fertilization in the tropical area. [Metho... [Objective] This study aimed to reveal distribution characteristics of soil nutrients in tropical farmland, thereby providing a reference for cropland management and balanced fertilization in the tropical area. [Method] Combining field survey and laboratory analysis, distribution status of nutrients in arable land of Baisha Li Autonomous County of Hainan Province was investigated. [Result] The soil in Baisha Li Autonomous County was acidic in overall with average pH value of 5.0. it had medium organic matter level (average of 19.3 g/kg) and rich alkali-hydrolyzable nitrogen content, but was lack of available phosphorus and available potassium. The spatial distribution of available nitrogen, available phosphorus and available potassi- um in the soil was uneven. The spatial distribution of soil nutrients was mainly related to soil parent materials of the investigated area and pH value of the investigated soil. [Conclusion] According to the distribution characteristics of nutrients in the soil, awareness of land use and land maintenance should be strengthened, application amount of organic fertilizers should be increased, chemical fertilizers should be applied rationally, and fertilization structure should be optimized in the future. 展开更多
关键词 FARMLAND Soil nutrients Tropical area Nutrient balance
下载PDF
Synthesis Scheme for Low Power Designs Under Timing Constraints 被引量:5
11
作者 王玲 温东新 +1 位作者 杨孝宗 蒋颖涛 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2005年第2期287-293,共7页
To minimize the power consumption with resources operating at multiple voltages a time-constrained algorithm is presented.The input to the scheme is an unscheduled data flow graph (DFG),and timing or resource constrai... To minimize the power consumption with resources operating at multiple voltages a time-constrained algorithm is presented.The input to the scheme is an unscheduled data flow graph (DFG),and timing or resource constraints.Partitioning is considered with scheduling in the proposed algorithm as multiple voltage design can lead to an increase in interconnection complexity at layout level.That is,in the proposed algorithm power consumption is first reduced by the scheduling step,and then the partitioning step takes over to decrease the interconnection complexity.The time-constrained algorithm has time complexity of O(n 2),where n is the number of nodes in the DFG.Experiments with a number of DSP benchmarks show that the proposed algorithm achieves the power reduction under timing constraints by an average of 46 5%. 展开更多
关键词 low power multiple supply voltages partitioning timing constraints SCHEDULING
下载PDF
Division of forest fuel type areas of Heilongjiang Province by using GIS 被引量:4
12
作者 单延龙 胡海清 +1 位作者 刘宝东 李雪峰 《Journal of Forestry Research》 SCIE CAS CSCD 2002年第1期61-66,84,共6页
Eight factors, including forest coverage, fuel load, species composition, elevation, monthly mean temperature, monthly mean relative humidity, monthly mean wind velocity, and monthly mean precipitation of fire season,... Eight factors, including forest coverage, fuel load, species composition, elevation, monthly mean temperature, monthly mean relative humidity, monthly mean wind velocity, and monthly mean precipitation of fire season, were considered and the methods of weight, the cumulative probability, ARC/INFO technique, and raster-to-vector conversion were adopted in division of forest fuel type area. Firstly, the electronic maps of forest distribution and administrative divisions were built, then overlaid and transformed to the real-world coordinates. Finally, the forest fuel type areas of Heilongjiang Province including 81 counties were divided into five grades, accounting for 16%, 17%, 17%, 11%, and 38% respectively. The grade Ⅰ fuel type areas with highest fire danger rating mainly distributed on Daxinganling Mountains, Xiaoxinganling Mountains, and Zhangguangcailing Mountains, the grade Ⅴ fuel type areas mainly centralized on Songnen Plain, Sanjiang Plain, and other Plains, and other forest fuel type areas (grades Ⅱ, Ⅲ, and Ⅳ) were situated between plains and mountainous areas. 展开更多
关键词 GIS Forest fuel type ARC/INFO Heilongjiang Province
下载PDF
ITS1 SEQUENCES OF NUCLEAR RIBOSOMAL DNA IN WILD RICES AND CULTIVATED RICES OF CHINA AND THEIR PHYLOGENETIC IMPLICATIONS 被引量:22
13
作者 周毅 邹喻苹 +2 位作者 洪德元 周骏马 陈受宜 《Acta Botanica Sinica》 CSCD 1996年第10期785-791,共7页
The first internal transcribed spacer(ITS1) of nuclear ribosomal DNA of three wild rice species and two subspecies of cultivated rice, which are distributed in China, was amplified using PCR technique and sequenced wi... The first internal transcribed spacer(ITS1) of nuclear ribosomal DNA of three wild rice species and two subspecies of cultivated rice, which are distributed in China, was amplified using PCR technique and sequenced with automated fluorescent sequencing. The sequences of ITS1 ranged from 193 bp to 218 bp in size and G/C content varied from 69.3% to 72.7%. In pairwise comparisons among the five taxa, sequence site divergence ranged from 1.5% to 10.6%. Phylogenetic analysis of ITS1 sequences using Wagner parsimony generated a single well resolved tree, which revealed that Oryza rufipogon was much more closely related to cultivated rice species than to the other two wild species. Oryza granulata was less closely related to either cultivated rice species or the other two wild species, and might be a unique and isolated taxon in the genus Oryza. The phylogenetic relationships of the three wild rice species and two cultivated rice subspecies inferred from ITS1 sequences is highly concordant with those based on the molecular evidence from isozyme, chloroplast DNA (cpDNA), mitochondrial DNA(mtDNA) and nuclear DNA (nDNA) of the genus Oryza . 展开更多
关键词 Wild rice Cultivated rice ITS1 of rDNA Sequence analysis PHYLOGENY
下载PDF
Sequence Analysis of ITS Region of rDNA of Alternaria Nees. from Some Areas of China 被引量:1
14
作者 何劲 康冀川 +2 位作者 谢红艳 雷帮星 文庭池 《Agricultural Science & Technology》 CAS 2009年第1期51-55,共5页
[Objective] The study aimed to identify Alternaria Nees from some areas of China at molecular level by analyzing the rDNA ITS sequence. [ Method ] The DNA sequences coding for the 5.8S rDNA and the flanking internal t... [Objective] The study aimed to identify Alternaria Nees from some areas of China at molecular level by analyzing the rDNA ITS sequence. [ Method ] The DNA sequences coding for the 5.8S rDNA and the flanking internal transcribed spacers ( ITS1 and ITS2) were amplified by PCR with universal primers ITS4 and ITS5 and subsequently sequenced for 34 Alternaria isolates from different areas of China. [Result] Sequences analysis showed that 5.8S rDNA was 159 bp and no variation in tested 34 isolates. There had variables sites in ITS. The isolates that had same sequences as A. tenuissima or A. alternata all put up eurytopicity to area and host. The variables sites of the isolates showed the diver- sity of Alternaria in the hosts of Oleaceae, Rosaceae and Solanaceae. At the same time that ITS could not clearly separated the isolates was indicated. The results indicated that the phylogenetic relationship were not closely related to the geographical origin and hosts of these isolates. [ Conclusion] The sequence analysis of ITS region could provide theory basis for the identification of Alternaria Nees.. 展开更多
关键词 Alternaria Nees. Sequences analysis ITS 5.8SrDNA
下载PDF
PARALLEL COMPUTATION OF 3-D HYPERSONIC FLOWS ON UNSTRUCTURED HYBRID MESHES 被引量:3
15
作者 王江峰 伍贻兆 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2005年第3期200-205,共6页
A parallel virtual machine (PVM) protocol based parallel computation of 3-D hypersonic flows with chemical non-equilibrium on hybrid meshes is presented. The numerical simulation for hypersonic flows with chemical n... A parallel virtual machine (PVM) protocol based parallel computation of 3-D hypersonic flows with chemical non-equilibrium on hybrid meshes is presented. The numerical simulation for hypersonic flows with chemical non-equilibrium reactions encounters the stiffness problem, thus taking huge CPU time. Based on the domain decomposition method, a high efficient automatic domain decomposer for three-dimensional hybrid meshes is developed, and then implemented to the numerical simulation of hypersonic flows. Control equations are multicomponent N-S equations, and spatially discretized scheme is used by a cell-centered finite volume algorithm with a five-stage Runge-Kutta time step. The chemical kinetic model is a seven species model with weak ionization. A point-implicit method is used to solve the chemical source term. Numerical results on PC-Cluster are verified on a bi-ellipse model compared with references. 展开更多
关键词 hypersonic speed hybrid mesh domain decomposition PARALLELIZATION
下载PDF
Spatial Distribution of Soil Salinization Based on GIS in Tianjin Binhai New Area 被引量:3
16
作者 廉晓娟 李明悦 +3 位作者 王艳 张余良 贺宏达 王正祥 《Agricultural Science & Technology》 CAS 2012年第5期1046-1049,共4页
The distribution of soil salinization was investigated based on GIS and field sampling in Tianjin Binhai New Area. The results showed that the average soil total salt content was 0.818%, with an average pH of 8.43, an... The distribution of soil salinization was investigated based on GIS and field sampling in Tianjin Binhai New Area. The results showed that the average soil total salt content was 0.818%, with an average pH of 8.43, and the average CI and Na+ contents were 0.27% and 0.22%, respectively. Presenting zonal distribution feature, the soil total salt content increased gradually from west to east of Binhai New Area. Statistics on the distribution areas of different salinization degrees showed that the area of non-salinzed soils only accounted for 3.18% of the total area; with an area of 107.43 km2, mild saline soil accounted for 6.34% of the total area; the area of moderate saline soil was 173.51 km2, accounting for 10.24%; and the area of sal- inzed soils was 217.36 km2, accounting for 12.82% of the total soil area. The area of saline soils (total salt content 〉0.6%) was 1 142.8 km2, accounting 67.42% of the total land area in Binhai New Area. And the areas for the soils with total salt content of 0.6%-1.0%, 1.0%-1.5%, 〉1.5% were respectively 388.47, 411.82, 342.51 km2, accounting for 22.92%, 24.3%, 20.21% of the total area. 展开更多
关键词 GIS Soil satinization Soil total salt content Binhai New Area Spatial distribution
下载PDF
Study on Plant Landscape Design of Urban Comprehensive Park 被引量:3
17
作者 胡牮 华鑫娜 颜玉娟 《Agricultural Science & Technology》 CAS 2017年第12期2563-2566,共4页
The urban comprehensive park is the main body of the urban environment construction, and the plant landscape is the most important landscape element of the comprehensive park. It is helpful for the landscape design of... The urban comprehensive park is the main body of the urban environment construction, and the plant landscape is the most important landscape element of the comprehensive park. It is helpful for the landscape design of the comprehensive park to improve the environmental quality and the sustainable development of the city. Taking the "Nanjiang Park" in Xiaoshan District of Hangzhou as the research object, the landscape design of plants was explored and analyzed. The results showed that there were significant differences in the application forms of plant land- scapes in different functional zones in comprehensive parks. The specific forms of the garden elements had different needs of plant landscape construction. According to the results of case studies, it found that comprehensive parks could improve the functions, create the aesthetic sense, enhance the atmosphere and enhance the taste through plant landscape design. In addition, corresponding suggestions were put forward according to the current situation with the aim to provide references for the future plant landscape design related with garden greens. 展开更多
关键词 Plant landscape Comprehensive park Function zoning Landscape ele-ments Optimization analysis
下载PDF
Study on Regionalization of High Efficiency Eco-agriculture in Eco-economic Zone of Poyang Lake 被引量:11
18
作者 戴天放 章志发 《Agricultural Science & Technology》 CAS 2010年第8期57-60,共4页
The high efficient eco-agricultural zone in Eco-economic Region of Poyang Lake was divided into three different areas. 12 indicators including per capita cultivated land,forest coverage,comprehensive utilization rate ... The high efficient eco-agricultural zone in Eco-economic Region of Poyang Lake was divided into three different areas. 12 indicators including per capita cultivated land,forest coverage,comprehensive utilization rate of straw,the ratio of the effective irrigation area to the arable land,amount of pesticide usage per unit area of arable land,the output value ratio of planting industry,the output value ratio of forestry and fruit industry,the output value ratio of stock farming,the output value ratio of fishery,the proportion of sown area of crop,proportion of sown area of oil plants and the proportion of sown area of vegetable were screened to construct the indicator system of regionalization of high efficient eco-agriculture. The average index values of the high efficient eco-agricultural regionalization of three regions were obtained,the development direction of the efficient eco-agriculture construction of three areas were analyzed according to the natural resources characteristics f eco-agricultural and requirements of high efficient eco-agricultural development of the regions. 展开更多
关键词 Poyang Lake Eco-economic Region Efficient eco-agriculture REGIONALIZATION
下载PDF
Vegetation-Climate Relationship and Its Application in the Division of Vegetation Zone in China 被引量:38
19
作者 方精云 宋永昌 +1 位作者 刘鸿雁 朴世龙 《Acta Botanica Sinica》 CSCD 2002年第9期1105-1122,共18页
Distribution of vegetation is closely coupled with climate; the climate controls distribution of vegetation and the vegetation type reflects regional climates. To reveal vegetation_climate relationships is the foundat... Distribution of vegetation is closely coupled with climate; the climate controls distribution of vegetation and the vegetation type reflects regional climates. To reveal vegetation_climate relationships is the foundation for understanding the vegetation distribution and theoretically serving vegetation regionalization. Vegetation regionalization is a theoretical integration of vegetation studies and provides a base for physiogeographical regionalization as well as agriculture and forestry regionalization. Based on a brief historical overview on studies of vegetation_climate relationships and vegetation regionalization conducted in China, we review the principles, bases and major schemes of previous vegetation regionalization and discuss on several contentious boundaries of vegetation zones in the present paper. We proposed that, under the circumstances that the primary vegetation has been destroyed in most parts of China, the division of vegetation zones/regions should be based on the distribution of primary and its secondary vegetation types and climatic indices that delimit distribution of the vegetation types. This not only reveals the closed relationship between vegetation and climate, but also is feasible practically. Although there still are divergence of views on the name and their boundaries of the several vegetation zones, it is commonly accepted that there are eight major vegetation regions in China, i.e. cold temperate needleleaf forest region, temperate needleleaf and broadleaf mixed forest region, warm temperate deciduous broadleaf forest region, subtropical evergreen broadleaf forest region, tropical monsoon forest and rain forest region, temperate steppe region, temperate desert region, and Qinghai_Xizang (Tibetan) Plateau high_cold vegetation region. Analyzing characteristics of vegetation and climate of major vegetation boundaries, we suggested that: 1) Qinling Mountain_Huaihe River line is an important arid/humid climatic, but not a thermal climatic boundary, and thus can not also be regarded as the northern limit of the subtropical vegetation zone; 2) the northern limit of subtropical vegetation zone in China is along the northern coast of the Yangtze River, from Hangzhou Bay, via Taihu Lake, Xuancheng and Tongling in Anhui Province, through by southern slope of the Dabie Mountains, to Wuhan and its west, coinciding with a warmth index ( WI ) value of 130-140 ℃·month; 3) the tropical region is limited in a very small area in southeastern Hainan Island and southern edge of Taiwan Island; and 4) considering a significant difference in climates between the southern and northern parts of the warm temperate zone, we suggested that the warm temperate zone in China is divided into two vegetation regions, deciduous broadleaf woodland region and deciduous and evergreen broadleaf mixed forest region, the Qinling Mountain_Huaihe River line being as their boundary. We also claimed that the zonal vegetation in North China is deciduous broadleaf woodland. Finally, we emphasized the importance of dynamic vegetation regionalization linked to climate changes. 展开更多
关键词 China dynamic vegetation regionalization arid/humid climate northern limit of subtropical zone Qinling Mountain_Huaihe River line thermal climate vegetation_climate relationship vegetation regionalization vegetation zone
下载PDF
Discussions on taxonomy of genus Betula in northeast China 被引量:1
20
作者 周蕴薇 聂绍荃 张玉红 《Journal of Forestry Research》 SCIE CAS CSCD 2002年第3期235-238,252,共4页
Many researches have been carried out on the taxonomy of Betula in northeast of China, but the classification of species and subdivision of species had some divergences at all times, which led to a disorder for develo... Many researches have been carried out on the taxonomy of Betula in northeast of China, but the classification of species and subdivision of species had some divergences at all times, which led to a disorder for developing and utilizing resources of Betula. In this paper, species and subdivision of Betula were classified not only according to the wax sample of Betula but also the comprehensive taxonomy of population characters, geographical distribution, and the habitat. Theconclusion supported the Fu Pei-yuns?(1995) viewpoint of the taxonomy of Betula in the northeast of China. But B. mandshurica (Regel) Nakai should be considered as one single species, the name of B. platyphyla Suk.var phellodendroidesTung should be the synonym of B. platyphyla var platyphyla, and B. ermanii Cham.var.yingkiliensis liou et Wang should be incorporated into B. ermanii Cham. B. ovalifolia Rupr should not be regarded as a variety of B. fruticosa Pall. but as one single species. 展开更多
关键词 TAXONOMY BETULA Northeast forest region
下载PDF
上一页 1 2 43 下一页 到第
使用帮助 返回顶部