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951.
战略性矿产是国家资源宏观调控和的监督管理的重点对象, 加强战略性矿产研究、明确自身比较优势和薄弱环节。战略性非金属矿产是指对国家经济发展和国家安全至关重要的非金属矿产。建议将萤石、高纯石英、石墨、硼、金红石、硅藻土、叶蜡石、石榴子石、金刚石、泥炭、重晶石等11种非金属矿产为战略性非金属矿产, 对其重要性及用途、资源供需形势等进行研究, 为国家制定勘查投入规划及制定矿业发展政策提供参考。对于完善全国矿产资源规划中的战略性矿产资源目录、为国家相关产业政策制定提供借鉴参考具有重要意义。  相似文献   
952.
The study aims to simulate the peri-urban growth dynamics in a growing region of India using Weights of Evidence (WOE) based cellular automata model. The growth process was expressed as a function of four causative variables corresponding to which seven data layers were generated in a Geographic Information Systems environment. The model was calibrated for the period 2000–2005 using Kappa indices and fuzzy set theory based two way comparison method. The Kappa value was 0.7, while the value of Klocation and Khisto were 0.81 and 0.93, respectively. The fuzzy similarity values increased for small to large neighbourhood sizes which showed that the model was able to simulate the contiguous and dense growth. However, for dispersed and isolated growth the model showed less accuracy. The model was validated for period 2005–2010 and revealed a Kappa value of 0.88, while value of Klocation and Khisto were 0.91 and 0.96, respectively.  相似文献   
953.
王安建 《地球学报》2023,44(2):257-260
关键矿产是指对国家经济发展、国防安全至关重要、对战略新兴产业发展不可或缺,同时又存在供应风险的一类矿产资源。不同国家关键矿产的种类因国家和经济发展阶段不同而存在差异。21世纪以来,美、欧、日、澳、加等发达国家相继发布了其关键矿产目录,而中国多年来一直将这类矿产统称为战略性矿产,迄今尚未发布相关关键矿产目录。本专辑讨论了中国战略性关键矿产目录厘定,需求分析,供应风险评估和战略性关键矿产全球治理问题。  相似文献   
954.
A new type of steel plate shear wall (SPSW) with oval-curved architectural openings and vertically flexible horizontal connection elements is proposed. The vertical flexibility of the wall accommodates the construction settlement introduced by column contraction under the dead loads of the upper stories and allows sequential installation from the lower stories. A quasi-static cyclic loading test and finite element (FE) analysis verified the stable seismic behaviors of the ovally-perforated vertically-flexible steel plate shear wall (OVSPW). The results of FE parametric analysis showed that an OVSPW with an appropriate thickness of boundary elements effectively accommodated the construction settlement that could lead to large in-plane compression for a conventional SPSW. The horizontal connection elements made of steel tubes realized the vertical stiffness of OVSPW to less than 2% of the original value without changing the lateral stiffness. New design equations of the OVSPW were derived through integral and extreme value solutions to predict the mechanical behavior of OVSPW.  相似文献   
955.
The introduction of the Single Aliquot Regenerative Dose (SAR) protocol established luminescence dating as an indispensable tool in Quaternary research. A major impediment of this technique is the time required for measurements, since the protocol is repeated for various aliquots of each sample to establish a sound statistical basis. To reduce the demand on machine time, Standardised Growth Curve (SGC) approaches have been developed and successfully applied for samples from some regions. However, differences in luminescence properties require careful testing of this techniques when applied to samples with other geological background.In this study, the application of the SGC approach of Li et al. (2016) is successfully verified for multi-grain aliquots of coarse-grained quartz and feldspar samples from three sites in northern Switzerland. In-depth quality control measures ensure the reproducibility of equivalent dose (De) values obtained by the common SAR protocol and sample-specific SGCs. For both minerals little sensitivity was found to the re-normalisation dose and the sample-specific SGCs performed well. In contrast to other studies, no different types of dose response curve shape were observed for quartz. A minimum number of full SAR measurements of eight and six aliquots per sample has been found appropriate for quartz and feldspar, respectively. For the fading corrected feldspar signals, site-specific SGC worked well and De values of up to 800 Gy were consistently replicated.In summary, sample-specific SGCs for samples from northern Switzerland perform well and their application reduces measurement times by up to 70%. The construction of a regional SGC may well be beneficial, however, caution regarding the choice of given doses and curve fitting is recommended and a thorough verification of SGC results is needed before the technique is widely applied.  相似文献   
956.
Through in‐depth interviews and participant observation with 40 1.5 generation Korean New Zealander returnees, we explore life trajectories and identify both short‐ and long‐term reasons for return. Short‐term reasons for return include moving home when entering adulthood in order to begin a career, gaining new experiences and finding a future spouse. Longer term influences include the difficulties of living as minority‐status immigrants in the host society, transnational connections and a longing for a sense of ‘home’. Our consideration of longer term migration strategies sheds light upon the often forgotten difficulties and complexities that can underlie an individual's return.  相似文献   
957.
南极磷虾的区域特色、资源保有量优势和广泛的应用价值,使它成为重要的战略资源。南极磷虾商业化开发战略是海洋战略的重要组成部分,其资源特色为战略制定与实施提供了支撑,符合战略性新兴产业发展要求。基于中国海洋开发的战略环境,结合南极磷虾资源特色,评估其战略能力,确立发展目标为形成并完善南极磷虾资源开发的产业体系,确立发展战略重点为跟踪南极磷虾资源养护管理措施变化和开发利用政策、中国南极磷虾产业发展模式及风险评估、中国发展南极磷虾产业关键技术突破与产业化机制、中国发展南极磷虾产业的政策措施与保障机制研究。  相似文献   
958.
Using the Celtic Sea and the North Sea as case studies, the fleet-based approach is shown to be the pathway to implement an effective ecosystem approach to fisheries management (EAFM) in European seas. First, a diagnostic on the health of each ecosystem is proposed based on the reconstruction of long time-series of catch, the analysis of mean indicators or stocks trajectories derived from ICES stock assessment results, and the analysis of ecosystem indicators. Then, a fleet-based synthesis is presented using indicators of both the ecological impact and the economic performances of the major fleets operating within each ecosystem. In particular, assessment diagrams show whether each fleet segment, on average, sustainably exploits the stocks. Although results are preliminary due to the poor quality of available data, the analysis shows that simple indicators can be estimated and clearly highlight contrasts between fleet segments. Such an approach contributes to the evolution from a stock-based to a fleet-based management, which reflects the ecological, economical and social pillars of the sustainable development of fisheries.  相似文献   
959.
960.
Since 1967, the alumina plants in the Marseilles area (Barasse and Gardanne) have been discharging the mineral residue (i.e., red mud) resulting from the alkaline processing of bauxite into the submarine Cassidaigne canyon (north-western Mediterranean Sea) through pipes situated at 320-330 m in depth. The Barasse pipe stopped being used in 1988. From 1987 to 1996, many decrees and regulations were promulgated by the French State to rule the conditions under which the Gardanne alumina refinery was authorized to dispose of the bauxite residue in the sea. The refinery was required: (i) to study the hydrodynamic circulation in the Cassidaigne canyon to evaluate the potential dispersion and transport of fine elements discharged into the water mass and their impact on the pelagic ecosystem; (ii) to survey the marine environment every five years to control the expansion and thickness of the red mud deposit and compare the evolution of the benthic macrofauna at representative sampling sites in the environment affected by the red mud discharge with that of reference sites outside of the red mud plume; (iii) to study the effect of the discharge on fishing activities; and (iv) to investigate the toxicity of the red mud, particularly its persistence, accumulation, interaction and effect on the marine ecosystem, paying special attention to the bio-accumulation of chromium and vanadium. A Scientific Committee was created to insure an independent evaluation of the studies promised by the manufacturer in response to the State’s regulations. Since the beginning of the 1960s, data have been accumulating on the structure and long-term functioning of the Cassidaigne bathyal ecosystem. This paper presents the collaborative efforts of the State-Manufacturer-Committee triplet and summarizes the main results obtained during the last period’s sea campaigns (1991-2007). This paper also illustrates how national regulations concerning manufacturers, such as Gardanne alumina refinery, have provided new knowledge about the structure and functioning of a bathyal ecosystem in the Cassidaigne canyon in the north-western Mediterranean Sea.  相似文献   
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