共查询到20条相似文献，搜索用时 31 毫秒
1.
Yiqian Jiang Chi Zhang Zhenjiang Ye Binduo Xu Yongjun Tian Yoshiro Watanabe 《中国海洋大学学报(英文版)》2020,19(2):446-452
The Japanese Spanish mackerel Scomberomorus niphonius(Cuvier,1832)is widely distributed in the subtropical and temperate waters of the northwestern Pacific Ocean,supporting one of the most important commercial fisheries in China.However,ignoring the potential population structure changes induced by fishing pressure and climate change may undermine the population stability under the current management strategy.In this study,the population structure of the Japanese Spanish mackerel was investigated based on a morphometric truss network system.A total of 534 individuals were randomly collected from commercial gill nets spanning eight major spawning grounds in the Bohai,Yellow,and East China Seas during the peak spawning seasons respectively.A total of 17 measurements(including eye diameter)were conducted in each specimen and subjected to principal component analysis(PCA)and discriminant function analysis(DFA).The results of PCA indicated that the first two factors cumulatively caused 78.38%of the total morphometric variation and observable differences,primarily fin the caudal and trunk areas.The results of DFA revealed that the eight spawning groups can be divided into three stocks,i.e.,southern,middle,and northern stocks,with 68.7%of total accuracy.In contrast to previous studies,the spawning groups of the Japanese Spanish mackerel demonstrated a tendency to disperse to northern regions.In conclusion,this study found that to maintain the stability of the population structure and the total production of Japanese Spanish mackerel S.niphonius(Cuvier,1832),a newly revised management method should be developed and implemented. 相似文献
2.
STUDY ON THE SPATIAL PATTERNS OF LAND-USE CHANGE AND ANALYSES OF DRIVING FORCES IN NORTHEASTERN CHINA DURING 1990-2000 总被引：4，自引：1，他引：3
Land-use change is an important aspect of global environment change. It is, in a sense, the direct result of human activities
influencing our physical environment. Supported by the dynamic serving system of national resources, including both the environment
database and GIS technology, this paper analyzed the land-use change in northeastern China in the past ten years (1990–2000).
It divides northeastern China into five land-use zones based on the dynamic degree (DD) of land-use: woodland/grassland —
arable land conversion zone, dry land — paddy field conversion zone, urban expansion zone, interlocked zone of farming and
pasturing, and reclamation and abandoned zone. In the past ten years, land-use change of northeastern China can be generalized
as follows: increase of cropland area was obvious, paddy field and dry land increased by 74.9 and 276.0 thousand ha respectively;
urban area expanded rapidly, area of town and rural residence increased by 76.8 thousand ha; area of forest and grassland
decreased sharply with the amount of 1399.0 and 1521.3 thousand ha respectively; area of water body and unused land increased
by 148.4 and 513.9 thousand ha respectively. Besides a comprehensive analysis of the spatial patterns of land use, this paper
also discusses the driving forces in each land-use dynamic zones. The study shows that some key biophysical factors affect
conspicuously the conversion of different land-use types. In this paper, the relationships between land-use conversion and
DEM, accumulated temperature (⩾10°C) and precipitation were analysed and represented. We conclude that the land-use changes
in northeast China resulted from the change of macro social and economic factors and local physical elements. Rapid population
growth and management changes, in some sense, can explain the shaping of woodland/grassland — cropland conversion zone. The
conversion from dry land to paddy field in the dry land — paddy field conversion zone, apart from the physical elements change
promoting the expansion of paddy field, results from two reasons: one is that the implementation of market-economy in China
has given farmers the right to decide what they plant and how they plant their crops, the other factor is originated partially
from the change of dietary habit with the social and economic development. The conversion from paddy field to dry land is
caused prmarily by the shortfall of irrigation water, which in turn is caused by poor water allocation management by local
governments. The shaping of the reclamation and abandoned zone is partially due to the lack of environment protection consciousness
among pioneer settlers. The reason for the conversion from grassland to cropland is the relatively higher profits of farming
than that of pasturing in the interlocked zone of farming and pasturing. In northeastern China, the rapid expansion of built-up
areas results from two factors: the first is its small number of towns; the second comes from the huge potential for expansion
of existing towns and cities. It is noticeable that urban expansion in the northeastern China is characterized by gentle topographic
relief and low population density. Physiognomy, transportation and economy exert great influences on the urban expansion.
Foundation item: Under the auspices of Knowledge Innovation program Key Project of the Chinese Academy of Sciences (KZCX-2-308).
Biography: LIU Ji-yuan (1947 - ), male, a native of Shanghai Municipality, professor, Director General of Institute of Geographical
Sciences and Natural Resources Research, the Chinese Academy of Sciences. His research interests include environment and resources,
remote sensing and geography. 相似文献
3.
Space-time relationship between urban municipal district adjustment and built-up area expansion in China 总被引：1，自引：1，他引：0
Municipal district adjustment and built-up area expansion are two main forms of urban spatial expansion. Using geometric methods, this study constructed a space-time path method to characterize the space-time relationship between municipal district adjustment and built-up area expansion, and drew the space-time path sets of major prefecture level cities from 2000 to 2010 by constructing a coordinate system of the standardized built-up areas and municipal district areas. This divided them into four quadrants, namely, H-H, L-H, L-L, and H-L, based on the relative mean value to evaluate overall and individual stability by three indexes of the trajectory vectors, namely, direction, length, and slope. Results provide the following conclusions. 1) Municipal district adjustment is an effective spatial expansion way for city-scale promotion in China. Since 2000, municipal district adjustments have been mainly distributed in the eastern coastal regions and mid-western capital cities along with their surrounding cities. 2) Municipal district adjustment affects the scale and status of a city in China. Many cities that have expanded municipal districts behave stably and cross quadrants. 3) Great majority second-tier cities have effectively promoted their scale and status through municipal district adjustment. The municipal district adjustment of medium and small cities in the mid-west area is relatively advanced compared with city development. 4) Municipal district adjustment with minimal magnitude is severely restricted from upgrading the scale and status of a city. The transformation from entirely incorporated counties or cities to municipal districts should be the mainstream in future municipal district adjustment. 相似文献
4.
行政事业单位的内部招待所走向市场后,必须摒弃旧的传统观念,变资产管理为资产经营、变行政管理为质量控制、变传统管理为制度管理. 相似文献
5.
Smart urban development is an inevitable choice, and is essential to overall strength improvement. It is important to explore an urban smart development path which unites smart growth with driving shrinkage perfectly in forming scientific and sustainable development concept and responding to new normal strategic opportunities. Based on statistic data of 294 prefecture-level cities and above in China from 2000 to 2015, we analyzed spatial and temporal evolution of urban smart development in China by constructing a dynamic fitting model of urban land expansion, population growth, and economic development as well as the coefficient of variation of urban smart development(CVSD). Further efforts were then made to consider differential distribution regularity of urban smart development so as to understand the driving mechanisms of heterogeneous classification of urban smart development in China from different scales and scale variation. Our results indicate that: 1) the disordered growth tendency of urban cities in China is overall well controlled in the middle, and late research and it mainly presented a doublet coexistence of shrinkage disordered cities and smart developing cities. It is particularly obvious that Northeast China and East China have regarded shrinkage disordered cities and smart developing cities as main development tendency separately. 2) Areas with basic stability and relative variation were relatively dispersed across the time period, but the proportion was far beyond areas with significant variation. It demonstrates a relative equilibrium spatial and temporal differential evolution pattern of prefecture-level cities and above in China, except for Tongling, Lanzhou and Chaoyang. 3) prefecture-level cities and above in China are mostly characterized by shrinkage disordered and smart development classification under the background of different scale and scale variation from 2000–2015; however, the spatial resonance relation is not obvious. 4) There are many interaction factors forming an important driving mechanism in developing the spatial and temporal pattern of urban smart development in China, including natural geographical factors, industrial structure adjustment, human capital radiation, regional traffic accessibility, and government decision-making intervention. 相似文献
6.
The urban construction of Shanghai will come into a new area since China has deciared to exploit and open Pudong. Based on the analysis on economic development of China and the world, the developmental strategy for Shanghai should take the following contents into consideration: 1) Shanghai should be built into one of the most important intemational and modern supercity in Asian-Pacifie Region. 2) Shanghai should keep the position of the largest economic center of China and important port city for international trade. 3) Shanghai should be taken as growth pole of the Changjiang River Delta. According to the considderations mentioned above, the spatial distribution patten and the management of environment are discassed. 相似文献
7.
《中国海洋湖沼学报》2019,(6)
In recent years, fast economic development demands for more land use and thus many reclamation projects are initiated around the Sanmen Bay, Zhejiang, SE China in the East China Sea, for which tidal and storm surge levels are reassessed. A two-dimensional numerical model based on an advanced circulation model(ADCIRC) was applied to evaluate the impact of reclamation projects on tidal and storm surge levels in the bay. The results show that the shoreline relocation and topographic change had opposite effects on tidal heights. Shoreline relocation decreased the tidal amplitude, while siltation caused topographic change and increased the amplitude. Such variations of the amplitude were significant in the top areas of Sanmen Bay. Three types of typhoon paths were selected for a case study to investigate the impacts of shoreline relocation and topographic change on storm surge level. Results show that the maximum increase in storm surge level due to shoreline relocation was less than 0.06 m. The rise of peak surge level due to the change of topography was significant and the peak surge level rose when siltation increased. The maximum surge level rise occurred in the path of northwest landing typhoons, which exceeded 0.24 m at the top of the bay. The rise in peak surge level can potentially lead to severe damages and losses in Sanmen Bay and more attention needs to be paid to this problem of shoreline change in the future. 相似文献
8.
如何高效地动态监测、模拟和预测地表水过程是防灾减灾中亟待解决的问题,也是科学化的国土整治、区域规划、环境保护和水资源管理的基础。因此,本文利用统一计算设备架构(CUDA)对基于不规则三角网(TIN)的地表水动态模拟算法进行并行化改进,提出了一种基于CUDA的地表水动态模拟并行方法,旨在对任意时刻的地表水进行快速、高精度的动态模拟,从而满足实际的应用需求。该算法从高精度的数字高程模型(DEM)中提取地形特征点和流域线,生成受流域线约束的TIN。在此基础上,根据TIN表面的三角面坐标数据获取水流方向,再结合任意位置的降雨源点追踪得到流水线网络。基于曼宁公式,利用流水线流速计算核函数得到每条流水线上雨滴的流速,结合预设的时间,利用汇流量统计核函数得到该时刻的地表汇流量。具体的并行化过程包括数据的传输,CUDA中线程的划分和流水线流速计算核函数和汇流量统计核函数的实现。本文选取位于加拿大新布伦瑞克西北部的BBW(Black Brook Watershed)流域作为实验样区,将该算法与改进前的方法进行对比表明,该模型在保持精度的同时,大幅提高了模拟效率,加速比达到11.2;另外,通过与SWAT(Soil and Water Assessment Tool)模型进行对比,结果表明,该并行方法的Nash系数提高了88%,相关系数提高了5%。 相似文献
9.
Livelihood strategy change and land use change —Case of Danzam Village in upper Dadu River watershed, Tibetan Plateau of China 总被引：2，自引：1，他引：1
Land use change in rural China since the 1980s, induced by institution reforms, urbanization, industrialization and population
increase, has received more attention. However, case studies on how institution reforms affect farmers’ livelihood strategies
and drive land use change are scarce. By means of cropland plots investigations and interviews with farmers, this study examines
livelihood strategy change and land use change in Danzam Village of Jinchuan County in the upper Dadu River watershed, eastern
Tibetan Plateau, China. The results show that, during the collective system period, as surplus labor forces could not be transferred
to the secondary and tertiary industries, they had to choose agricultural involution as their livelihood strategy, then the
farmers had to produce more grains by land reclamation, increasing multiple cropping index, improving input of labor, fertilizer,
pesticide and adopting advanced agricultural techniques. During the household responsibility system period, as labors being
transferred to the secondary and tertiary industries, farmers chose livelihood diversification strategy. Therefore, labor
input to grain planting was greatly reduced, which drove the transformation of grain to horticulture, vegetable or wasteland
and decrease of multiple cropping index. This study provides a new insight into understanding linkages among institution reforms,
livelihood strategy of smallholders and land use change in rural China.
Foundation item: Under the auspices of National Natural Science Foundation of China (No. 40601006, 40471009), National Basic
Research Program of China (No. 2005CB422006) 相似文献
10.
本文以1990、1995、2000、2005年的上海市土地利用遥感监测数据为基本数据源,分析了1990-2005年上海市城市空间扩展 的时空特征。同时利用SLEUTH模型对城市空间扩展进行了模拟和精度验证,并对未来30年上海市城市空间扩展进行了预测。结果显示:1990-2005年,上海市城市空间扩展明显,城市面积净增加81 278hm2,净增长10.14%;在扩展的时间过程上呈现先减缓后加剧的趋势,2000-2005年城市用地扩展最为剧烈,城市面积净增加40 668hm2,净增长5.08%,填海造陆是该时期城市扩展的典型特征。SLEUTH模型可以较好地模拟预测上海市城市空间扩展的时空过程,不同时期模拟与遥感监测结果的Kappa系数最高达到了0.8476;未来30年,上海市城市用地将以年平均增长率1.63%的速度扩展,2040年城市用地面积将达到152 685hm2。城市扩展将占用耕地41 824hm2,年平均占用耕地1200hm2。城市扩展的方式主要是边缘增长,东部的浦东新区沿五洲大道向海方向、南部的徐汇区沿沪闵高架路向南,以及西部的嘉定区和青浦区沿京沪高速两侧向西的地区 均是未来城市扩展的主要方向。 相似文献
11.
The recession and revitalization of old industrial cities concerns urban industrial evolution and its characteristics. Based on the theory of evolutionary resilience, we developed an analytical framework for the industrial structure evolution of old industrial cities, and applied the framework to a case study in Shenyang. The following conclusions are drawn. First, since 1978, Shenyang's industrial growth capacity has shown fluctuation between ‘contraction-expansion'. As the secondary industry has a much stronger expansionary and contractionary capacity for growth, this results in lacking stability leading to industrial structure transformation. Second, since 1999, the orientation towards a high-end manufacturing industry in Shenyang has weakened, and the evolution of the new and old growth path is characterized by low-end orientation. Third, since 2007, Shenyang's industrial innovation output capacity has dropped sharply which has been significantly affected by scientific and technological personnel and enterprise-owed science and technology institutions and to a less extent by RD expenditure. We applied the resilience theory to study the industrial evolution of an old industrial city, explored new study perspectives on industrial evolution and verified the applicability of the resilience theory. This paper provides a scientific reference for understanding the recent deceleration in economic growth in the Northeast old industrial base, and for exploring new paths toward revitalization. 相似文献
12.
Cultural Landscape Evolution of Traditional Agricultural Villages in North China —— Case of Qianzhai Village in Shandong Province 总被引：1，自引：0，他引：1
FANG Yangang LIU Jisheng 《中国地理科学(英文版)》2008,18(4):308-315
Agricultural village is an important rural type in China. The evolution process and mechanism of its cultural landscape are different from those of the industrialized village. The paper focuses this theme by a case study of Qianzhai Village of Qufu City, Shangdong Province. In the case of Qianzhai Village, the evolution of its settlement has experienced three stages： mechanical expansion, sprawling expansion and hollowing, and recentralization. The land- scape evolution of residents＇ houses has undergone three phases： traditional quadrangle house, one-storied house and multistoried house. The evolution of its land use has experienced three stages： circled stratification, fragment and intensive use, and concentration and extensive use. We can see that the main driving factors of cultural landscape evolution of agricultural village are the changes of rural population, society, economy and culture, which are influenced by the change of urban-rural relation, the national modernization process and economic development, the reform of family planning and land system, and the changes in governmental policies. In the future, the modernization, ecological trend, and individualization for residents＇ houses of agricultural villages in China will develop step by step. The recentralization of settlement and the scaled, sustainable, intensive land use are likely to be the trends of agricultural villages in China. 相似文献
13.
大都市区增长是当前中国城镇化发展的一种主要模式,如何确定其最佳空间增长形态是新型城镇化关注的重要内容之一。本研究立足于未来“生态城市”建设理念,从自然资源生态敏感性和城市发展适宜性角度构建双重约束条件,利用元胞自动机模型构建了生态空间胁迫下的城市增长过程模拟框架,探讨了边缘性增长、生态性增长与协调性增长3种发展模式,并从建设适宜性、生态安全性与斑块紧凑性等角度构建评价指标对模拟方案进行定量化对比。最后,以长江中游城市群的南昌大都市区进行实例应用,结果表明,协调性空间增长模式能最大程度降低城市建设对生态安全空间的侵蚀,大都市区在制定城市增长边界等空间政策时宜参考此种发展模式,基于生态空间胁迫分析的城市增长过程建模是一种有用的规划决策情景分析工具。 相似文献
14.
ZHANG Luo-cheng ZHU Tian-ming YAO Shi-mou 《中国地理科学(英文版)》2005,15(4):309-314
1IN TR O D U C TIO NC hina, as a developing country, is experiencing rapidpopulation grow th and land expansion,w hich has gen-erated considerable governm entalconcernsand scholar-ly attention (FA ZA L,2000).R esearchers have revealeda m assive increase i… 相似文献
15.
Mark Yaolin WANG 《中国地理科学(英文版)》2012,22(5):617-625
China is entering a critical and accelerating phase of urbanization.As one of the most urbanized regions in China,the Changjiang(Yangtze)River Delta has experienced dramatic urbanization and urban transformation.However,in the recent years,many changes have taken place in this region and there is limited attention to the regional urbanization path evolution,its problems and the way to solve these problems.Therefore,we should revisit the urbanization process in the Changjiang River Delta again.In this paper,we revisited urbanization paths of the Changjiang River Delta by data analysis,influence factors of urbanization by the Gray Relational Analysis,and major challenges to urbanization of the Changjiang River Delta by theoretical considerations.We found that the urbanization of the Changjiang River Delta had experienced several stages of large-scale spatial and urban system restructuring.Within the Changjiang River Delta,Shanghai,Zhejiang and Jiangshu had experienced different urbanization path with local characteristics.But with their development model gradually converging,their urbanization model is also converging.We also found that the major influence factors affecting the Changjiang River Delta urbanization were dynamic change and urbanization was driven by different key factors in different socio-economic development stages.Meanwhile,the Changjiang River Delta urbanization is facing many problems such as existing institutional arrangements,including the hukou(household registration)system and others which can not meet the needs of current socioeconomic development and urbanization.Therefore,it is imperative to promote institutional innovation and adopt a new urbanization development strategy for the sake of the orderly and sustainable urbanization development in the Changjiang River Delta. 相似文献
16.
Hainan Provine, with an land area of 34,170 km2, is the largest economic district for external development in China. With the further deepening of reform and openning up, some new problems of land resource exploitation and use have arisen. The changing tendency of land use is estimated as follows: Land use in economic exploitation, city development and traffic will be increased rapidly; hydraulic construction will occupy a part of land; the use of wasteland is increasing; and the total farmland and per capital farmland will decrease continously. In 2000, the occupied land should be controlled in 5 million mu (1 mu=1/ 15 ha), in which farmland is 160,000 mu. The farmland should be maintained in 6.5 million mu. Some measures to implement the strategy and object of land use are put forward: enhancing land management and administration; excuting land policy and making land management mechanism active; enhancing the efficiency of land use; and control the growth of population strictly. 相似文献
17.
The lake groups in the Songnen Plain are low plain lake groups, which are located in the temperate semihumid area in China.
They are characterized by small area, shallow basin, thick density and various types. In the try for classifying comprehensively
the lake groups, a classification system is developed based on three main factors, i.e. forming cause, water quantity and
water quality. The most internal character can be concisely grasped through three principal indexes and three auxiliary indexes
of three main factors. A sample of complicated changeable path is put forward for further analyzing and outlining these basic
types, in the meantime, it’s linking up easily with the classification system of the single factor. According to the regional
environment, the regional differences of the type composition and the principal types, the lake groups in the Songnen Plain
can be divided into 6 sub-regions.
Foundation item: Under the auspices of the National Natural Science Foundation of China(49671077).
Biography: LU Jin-fu (1938–), male, professor. His research interest includes paleo-environment in the Quaternary. 相似文献
18.
The role of railroad in the development of the american west 总被引：1，自引：0，他引：1
This paper explores the role of geographical expansion of railroads, one of the most important Fransportation vehicles, in the history of American west development, analyses its implication on the unprecedented migration movement and the resulted urbanization in the west and concludes with the fact that the appropriate interference by the government, especially in the early period, is vital to regional development practice, because of market failure at the initial stage, infrastructure construction conducted by the government always plays as the first impetus to any regional development process. Only through this bridge, can some physical factors, such as population, be attracted to feed the backward area. As a result, cities grow fast and the region develops well. The experience can be shared by all countries. Besides reviewing the history of west development in America, focusing on the relationship between railroads expansion and urban growth, which was realized through population migration. A comparison on the particular pattern of regional development between U. S and China is made as well at the end. It is noted that despite of the common first impetus, government subsidies and the common final result, urbanization, the path for the America is bottom-up, whereas that for China is top down, that is to say, development should originate from big cities, then to towns, and finally radiate into rural areas. 相似文献
19.
《山地科学学报》2020,17(7):1763-1775
Over recent decades, historical areas conservation has become an important strategy to improve urban competitiveness in the global economy. As shown in existing studies that the conservation of historical areas mainly focused on the physical environment, there is still room for the non-physical study, and researches on the social network conservation in mountainous historical areas are particularly insufficient. Therefore, this paper aims to establish an evaluation system which is helpful for the social network conservation of historical areas. The evaluation system is based on social network analysis and the information of social relationships gathered in field surveys using a specifically designed questionnaire method in four mountainous towns in Chongqing, China. And it was analyzed from three perspectives, i.e., by the basic statistical properties, condensate subgroup, and centrality. Then five analysis indicators were conceived, including density, lambda set, k-core, degree centrality, and betweenness centrality. The analysis results demonstrate that the social networks of the four towns show different indicators, which are respectively relevant to completeness degree, edgerelatedness level, local stability, structural balance, and concentrated trend of social relationships. Results from SNA modeling indicate that neighborhood residents of historical areas who have more stable and healthier social relationships are relatively not easily be destroyed. The results also illustrate that the social networks structure is influenced by the terrain, form, and function of historical areas, and the change of historical areas is caused by "individual-family-society". Finally, the strategies guiding the social network conservation are put forward from two aspects. These findings suggest that the conservation and management of social network and aborigines in historical areas should be emphasized to increase the collective benefits and vitality. 相似文献
20.
在各种地形变的异常中,有些异常不能只归属于一次地震,而是一组地震的共同反映,我们称之为”地震组异常”。本文着重介绍了我国华北和西南地区三组强震的地形变异常。地震组的地形变异常曲基本特征是:异常的时间跨度大,分布范围广,群体出现。异常的种类有两种:一种是速率异常,另一种是形态异常。地震组的地形变异常,可以作为地震组预测的重要依据。 相似文献