Functional roles of interzonal migrating mesozooplankton in the western subarctic Pacific   总被引：1，自引：0，他引：1  

Toru Kobari  Akiyoshi Shinada  Atsushi Tsuda   《Progress in Oceanography》2003,57(3-4):279

Grazing experiments and production estimation based on life-history analysis of Neocalanus copepods (N. cristatus, N. plumchrus and N. flemingeri) were carried out in the Oyashio region to understand the carbon flows associated with the interzonal migrating copepods. These copepods, and also Eucalanus bungii, fed on nano- and micro-sized organisms non-selectively throughout the season. However, diatoms were the dominant food resource until May and organisms, such as ciliates were the major resource after May. Daily growth rate was estimated from the Ikeda–Motoda, Huntley–Lopez and Hirst–Sheader models. Since the growth rates were considered to be overestimates for the Huntley–Lopez model and underestimates for the other two models, we applied the weight-specific growth rates previously reported for these species in the Bering Shelf. Surface biomass of Neocalanus increased rapidly in June during the appearance of C5, and a successive increase of overwintering stock was evident in the deeper layer. The deep biomass decreased gradually from September to May during the dormant and reproduction period. N. cristatus has the largest annual mean biomass (2.3 gC m⁻²), followed by N. plumchrus (1.1) and N. flemingeri (0.4). Daily production rate of Neocalanus varied from 0.4 to 363.4 mgC m⁻² day⁻¹, to which N. cristatus was the largest contributor. Annual production was estimated as 11.5 gC m⁻² year⁻¹ for N. cristatus, 5.7 for N. plumchrus and 2.1 for N. flemingeri, yielding annual P/B ratio of 5 for each species. The annual production of Neocalanus accounted for 13.2% of the primary production in the Oyashio region. Their fecal pellets were estimated to account for 14.9% (0.7 gC m⁻² year⁻¹) of sinking flux of organic carbon at 1000-m depth. Moreover, their export flux by ontogenetic vertical migration, which is not measured by sediment trap observations, is estimated to be 91.5% (4.3 gC m⁻² year⁻¹) of carbon flux of sinking particles at 1000-m depth. These results suggest the important role of interzonal migrating copepods in the export flux of carbon.  相似文献   

新技术对测绘未来发展的影响   总被引：1，自引：0，他引：1  

闵宜仁 《地理信息世界》2000,(1)

空间技术和信息技术的飞速发展对测绘部门的未来将产生一系列的影响。本文从空间定位系统、高分辨率遥感、地理信息系统、计算机网络等技术在测绘活动中的作用和高新技术发展特点，分析新技术对测绘部门未来的需求结构、生产技术结构和生产组织结构等方面的影响。  相似文献   

Application of wellhead suction anchor technology in the second production test of natural gas hydrates in the South China Sea     

Bo Li  Bei-bei Kou  Bin Li  Jing Li  Jing Zeng  Qing-lei Niu  Yu-tao Shao  Ke-wei Zhang  Hao-yu Yu  Ying-sheng Wang 《China Geology》2022,5(2):293-299

Traditional suction anchor technology is mainly used in the fields of subsea structure bearing foundations, single-point mooring systems and offshore wind power. It is characterized by providing sufficient lateral and vertical bearing capacities and lateral bending moment. The anchor structure of a traditional suction anchor structure is improved with wellhead suction anchor technology, where a central pipe is added as a channel for drilling and completion operations. To solve the technical problems of a low wellhead bearing capacity, shallow built-up depth, and limited application of conductor jetting in the second production test of natural gas hydrates (NGHs) in the South China Sea (SCS), the China Geological Survey (CGS) took the lead in independently designing and manufacturing a wellhead suction anchor, which fulfilled the requirements of the production test. This novel anchor was successfully implemented in the second production test for the first time, providing a stable wellhead foundation for the success of the second production test of NGHs in the SCS.©2022 China Geology Editorial Office.  相似文献   

The production of meaning in outdoor recreation: A study of Norwegian practice     

《Norsk geografisk tidsskrift. Norwegian journal of geography》2012,66(3):199-206

Outdoor recreation policy and management have largely been occupied by questions related to use patterns: who participates in which activities, where and when? However, it is commonly held that ideas and practices mutually influence each other. In outdoor recreation, it could be expected that the observable use patterns are influenced by the meaning recreationists ascribe to their activities. In this study 14 narratives of outdoor recreation practices are analyzed, in order to broaden the traditional understanding of the meaning of outdoor recreation.  相似文献   

Production and R&D networks of foreign ventures in China: Implications for technological dynamism and regional development   总被引：2，自引：0，他引：2  

Y.H. Dennis Wei  Yu Zhou 《Applied geography (Sevenoaks, England)》2012,32(1):106-118

This paper analyzes the nature of FDI local networks in production and R&D activities in China and discusses their implications for technological dynamism and regional development. We investigate foreign ventures (or foreign-invested enterprises, FIEs) in the information and communication technology (ICT) industry, based on a large-scale survey of ICT firms conducted in three mega-city regions of China: Beijing, Shanghai-Suzhou, and Shenzhen-Dongguan. Our data show that FIEs in China are gradually localizing their production, but the extent of local embeddedness is contingent upon home country effects, local specific contexts and FDI-host region relationships. We have also found significant influence of industrial agglomeration on FDI location and network decisions. Beijing tends to have broader FDI sources and better integrated global-local networks, while in those regions dominated by FDI such as Suzhou and Dongguan, FIEs are thinly embedded with local economies and tend to establish global-local networks among themselves; local embeddedness is limited by a series of technological, institutional, spatial, and structural mismatches. Shanghai and Shenzhen are in between. More efforts are still needed to better integrate FDI with local economies and strengthen China’s local innovative capacities.  相似文献   

High energy neutron and pion-decay gamma-ray emissions from solar flares     

Edward L. Chupp James M. Ryan 《中国天文和天体物理学报》2009,9(1)

Solar flare gamma-ray emissions from energetic ions and electrons have been detected and measured to GeV energies since 1980. In addition, neutrons produced in solar flares with 100 MeV to GeV energies have been observed at the Earth. These emis-sions are produced by the highest energy ions and electrons accelerated at the Sun and they provide our only direct (albeit secondary) knowledge about the properties of the acceler-ator(s) acting in a solar flare. The solar flares, which have direct evidence for pion-decaygamma-rays, are unique and are the focus of this paper. We review our current knowl-edge of the highest energy solar emissions, and how the characteristics of the acceleration process are deduced from the observations. Results from the RHESSI, INTEGRAL and CORONAS missions will also be covered. The review will also cover the solar flare ca-pabilities of the new mission, FERMI GAMMA RAY SPACE TELESCOPE, launched on 2008 June 11. Finally, we discuss the requirements for future missions to advance this vital area of solar flare physics.  相似文献   

IMU/DGPS supported photogrammetry in China     

李英成  LI Xue-you  ZHAO Ji-cheng  GONG Xun-ping  TANG Liang 《测绘科学》2004,29(Z1):42-46

<正>People'sRepublicofChinaisoneofthemostrapidlydevelopingcountriesintheworldtoday.Thereisagreatdemandonhighlyactualandaccuratespatialinformationofthewholecountry,especiallyofWestChinawhichbecomesthefocusofdevelopmentoftheChinesegovernmentrightnowandinthenextyears,butwherestillnotenoughtopographicmapsareavailable.ThisraisesgreatchallengestothesurveyingandmappingcommunityinChina.FacingthenewchallengestheChineseAcademyofSurveyingandMapping(CASM)starteditspioneerworkearly2002toexplorenewtechniquesandtechnologiesavailabletodaytowardincreasingthemapproductivity.WithimportofaCCNS/AEROcontrolsysteminNovember2002,thefirstDGPS/IMU-basedphotogrammetricprojectinChinawassuccessfullyaccomplishedjointlybyCASM,theGermany-basedcompaniesIGIandTechedge.Twophotogrammetricblocksof1:4,000and1:20,000photoscales,respectively,wereflowninAnyang,China.Directgeoreferencingandintegratedsensororientationwereconducted.Resultsachievedwereprovenbyusinggroundcheckpointsandcomparedwiththoseofaerialtriangulation.Orthophotosgeneratedbasedondir  相似文献   

Constructing quality: The multinational histories of chocolate   总被引：1，自引：0，他引：1  

Julie L. Cidell  Heike C. Alberts 《Geoforum》2006,37(6):999-1007

Geographic research on food quality, while considering many of the ways in which quality is socially constructed, has largely focused on the place-based aspects of the raw materials of food production. Here, we use French convention theory to look at a highly processed food in order to show how place associations in the social construction of food quality extend to manufacturing. For chocolate, quality is based on material characteristics whose relative importance in determining quality depends on the country in which different stages of economic innovation took place. Struggles over the definition of quality chocolate, as exemplified by the “European Chocolate War,” show how quality issues are connected to geographies of manufacturing and innovation.  相似文献   

盐田光卤石生产工艺控制因素浅析   总被引：1，自引：1，他引：0       下载免费PDF全文

王石军 《盐湖研究》1998,6(4):41-48

根据察尔汗盐湖别勒滩卤水等温蒸发试验数据,结合大量生产取样分析资料,对盐田光卤石矿生产机理及其控制因素作了分析研究,并提出了管理措施。  相似文献   

稀有稀土资源的地质—经济分析     

林德松 《矿产与地质》1997,11(3):152-157

根据世界一些主要国家的稀有稀土资源政策以及稀有金属主要矿种（锂、铍、铌、钽、锆、稀土）的资源现状，指出世界稀有金属资源充足，可以保证未来相当长时期的需求。从总的看，世界稀有金属需求殷切，其产量和需求量呈逐年稳步增长趋势。  相似文献