Background:The establishment of national park system (NPS) is an important content of ecological civilization of China, and is an important measure to realize modernization of governance system and governance capacity in the field of natural and ecological protection.Aiming to obtain practical experience for reform of the NPS, central government of China launched pilot construction of the NPS in 2015.Progress: For assessing efficiency of pilot reforms in the past five years, we carried out in-depth investigation and research in 10 national parks (NPs).The result showed that: pilot reform of the NPS was reliably and orderly promoted and accumulated a batch of replicable and propagable experience, especially on top design of the NPS, establishment of management mechanism, law and regulations construction, ecological environment protection, strengthening foundation of protection management.However, there was also relative lack of laws, regulations and standards.Management system reform of the NPS did not reach the designated position.It was also lack of monitoring system of ecological environment.Financial support was still not mature, contradictions between natural protection and society development were still obvious.Perspective: This paper provides relational countermeasure and suggestion for law system construction, deepening the reform of management system, improving the ecological environment supervision mechanism, building diversified funds safeguard mechanism, and promoting to build, to manage and to share the NPs.This paper also provides reference and basis to formally build a batch of NPs, and to preliminary establish the NPS in 2021.
Research and observations indicate climate change has and will have an impact on Ontario field crop production. Little research has been done to forecast how climate change might influence the Canadian Federal-Provincial Crop Insurance program, including its premium rates and reserve fund balances, in the future decades. This paper proposes using a mixture of two normal yield probability distribution model to model crop yield conditions under hypothetical climate change scenarios. Then superimposes Crop Insurance premium rate and reserve fund balance calculations onto the yield model to forecast their trends and fluctuation situations in the future decades. We find under the scenarios where climate change alters the probability of a lower yield year occurring and where climate change alters yield averages, both have more significant impacts on premium rates and reserve fund balances, compared to the scenarios where climate change alters yield variations. The results of this research will help Agricorp Ltd. identify the likely frequency and magnitude of both insurance premium rate fluctuations and reserve fund balance fluctuations under different climate change scenarios. Therefore the results can be used to help Agricorp Ltd. identify and forecast both premium rate fluctuation risk and reserve fund liquidity risk.
Ferroelectricity is generally deteriorated or even vanishes when the ferroelectric films are downsized to unit cell scale. To maintain and enhance the polarization in nanoscale ferroelectrics are of scientific and technological importance. Here, giant polarization sustainability is reported in a series of ultrathin PbTiO3 films scaled down to three unit cells grown on NdGaO3 (110) substrates with La0.7 Sr0.3 MnO3 as bottom electrodes. Atomic mappings via aberration-corrected scanning transmission electron microscopy demonstrate the robust ferroelectricity for the sub-10 nm thick film. For the 1.2 nm thick film, the polarization reaches ≈50 µC cm-2 . The 2 nm thick film possesses a polarization as high as the bulk value. The films ranging from 10 to 35 nm display a giant elongation of out-of-plane lattice parameter, which corresponds to a polarization of 100 µC cm-2 , 20% larger than that of the bulk PbTiO3 . The giant enhancement of polarization in the present films is proposed to result from the charge transfer at the La0.7 Sr0.3 MnO3 /PbTiO3 interface, as supported by the anomalous decrease of Mn valence measured from X-ray photoelectron spectroscopy. These results reveal the significant role of charge transfer at interfaces in improving large polarizations in ultrathin ferroelectrics and are meaningful for the development of future electronic devices.
Many investigated data and experiences stated that the difference of annual agricultural products export amounts is relatively outstanding among different areas in China.There are many factors of affecting agricultural export currently.In general,they can be divided into inner factors and outer factors.This paper analysed the inner factors of affecting agricultural products export using the correlation analysis method with many data,and gave some policy suggestions for expanding export after concludes some results.
The article based on the theory of gray correlation matrix analyzes the eight factors affecting grain yield and the major food crops per hectare according to time serial in Heilongjiang province from 1990 to 2006.The analysis shows that agricultural machinery unit crops sown area is dynamic impact from 1990 to 1996 and from 2003 to 2006 in two phases,the units fertilizer sown in crops area of grain production is key factor in food production per hectare from 1996 to 2003,and analyzes the factors influencing soybean the yield per hectare of wheat,corn,rice,potato at various stages.
The impact of extreme climate on natural ecosystems and socioeconomic systems is more serious than that of the climate’s mean state. Based on the data of 1698 meteorological stations in China from 2001 to 2018, this study calculated the 27 extreme climate indices of the Expert Team on Climate Change Detection and Indices (ETCCDI). Through correlation analysis and collinearity diagnostics, we selected two representative extreme temperature indices and three extreme precipitation indices. The spatial scale of the impact of extreme climate on Normalized Difference Vegetation Index (NDVI) in China during the growing season from 2001 to 2018 was quantitatively analyzed, and the complexity of the dominant factors in different regions was discussed via clustering analysis. The research results show that extreme climate indices have a scale effect on vegetation. There are spatial heterogeneities in the impacts of different extreme climate indices on vegetation, and these impacts varied between the local, regional and national scales. The relationship between the maximum length of a dry spell (CDD) and NDVI was the most spatially nonstationary, and mostly occurred on the local scale, while the effect of annual total precipitation when the daily precipitation amount was more than the 95th percentile (R95pTOT) showed the greatest spatial stability, and mainly manifested at the national scale. Under the current extreme climate conditions, extreme precipitation promotes vegetation growth, while the influence of extreme temperature is more complicated. As regards intensity and range, the impact of extreme climate on NDVI in China over the past 18 years can be categorized into five types: the humidity-promoting type, the cold-promoting and drought-inhibiting compound type, the drought-inhibiting type, the heat-promoting and drought-inhibiting compound type, and the heat-promoting and humidity-promoting compound type. Drought is the greatest threat to vegetation associated with extreme climate in China.
The system constructs a virtual digital model of knee joint and makes full use of virtual reality technology to interpret and visualize it. All anatomical structures of the knee joint can be displayed comprehensively and clearly, so that students can understand the examination and surgical treatment of knee joint injuries. The system is equipped with different teaching links including simulation demonstration, autonomous learning, repeated training, intelligent evaluation, etc. It can endow students a relaxed and fast learning experience and stimulate students' learning interest and autonomous learning ability.Visualization of medical data, dynamic tissue model in knee joint cavity, stress deformation simulation of knee joint tissues and organs, demonstration of simulated minimally invasive surgery cases.
Abstract Orogenic gold (Au) deposits are the most important type, accounting for more than half of the world's proven Au reserves. They are mainly controlled by three key factors: (1) abundant andesitic rocks (SiO2 of 55–60 wt.%) at depth, which have systematically higher Au contents than other rock types; (2) a pervasive transition from greenschist facies to amphibolite facies metamorphism within a short period, which releases S2−-rich fluids that may scavenge Au from host rocks; and (3) deformation and fracturing under a compressive/transpressive tectonic regime. Orogenic belts at convergent margins are the best places for such mineralization because convergent margins are rich in andesites; the transition from greenschist to amphibolite facies recrystallization commonly occurs as a result of collision, compression, and thickening at convergent margins, forming large amounts of Au-rich fluids within a short period of time; and strong deformation and fracturing during orogenic processes provide channels for fluid transportation. Moreover, the overlying plate is injected and enriched by auriferous fluids released during amphibolite facies metamorphism of the subducting plate. The Pacific plate changed course by ∼80° (from SW to NW) at approximately 125–122 Ma, reflecting an altered thermal structure and the elevation of the South Pacific plate attending the appearance of the plume head that formed the Ontong Java large igneous province. Consequently, the tectonic regime changed from extension to compressive/transpressive in eastern China, causing deformation, thickening, and metamorphism of the overriding plate, especially along weak crustal belts (e.g. overlying plates of palaeosutures), which resulted in world-class mineralization of orogenic Au deposits. During this process, pyrite changed to pyrrhotite during the transition from greenschist to amphibolite facies, releasing sulphur. Sulphur mobilized and scavenged Au and other chalcophile elements into metamorphic ore-forming fluids. A series of NE-trending compressive faults were formed at ˜120 Ma as a result of continuous compression of the subducting Pacific plate, releasing these ore-forming fluids. Auriferous carbonate-rich quartz veins and/or metasomatized Au-bearing wall rocks were formed due to the decompression of the ascending ore-forming fluids. Orogenic belts along the margins of the North China craton and the Jiangnan block were the most favourable regions for mineralization. Compared with the former, the latter has much smaller proven Au reserves. However, more exploration is needed along the margins of the Jiangnan block. Promising targets include accessory faults and kink points of large, NE-trending Cretaceous faults that transect greenschist facies metamorphic rocks of the Niuwu and Jingtan Groups, etc. Keywords: Pacific plate directional changeorogenic gold depositseastern Chinaandesitic rocksJiangnan blockNorth China craton Acknowledgements The study was supported by a major project of the Chinese Academy of Sciences (KZCX1-YW-15), Ministry of Science and Technology of China (2012CB416703), the Natural Science Foundation of China (nos 41090374 and 41121002), and the Commonweal Geological Prospecting Project of Anhui Province (2011-8). We thanks Professor S.Y. Jiang for his constructive review comments and Dr Chuck Magee and Miss Elaine Chang for proofreading the manuscript. Contribution No. IS-1495 from GIGCAS. Notes
胶东地区探明金储量超过5000t，是我国最重要的金矿集区。玲珑金矿区位于胶东西北部招-平断裂北段，具有典型含金石英脉矿床的特征。矿区部分矿段产出富碲铋化物的明金矿石，是研究富碲铋化物金矿床成因和金超级富集机制的理想对象。通过显微岩相学观察、扫描电镜及电子探针分析，首次对胶东玲珑金矿区富碲铋化物明金矿石的矿物组合和形成机制进行了较为详细的研究。玲珑金矿区含明金矿石中的金矿物主要为含银自然金，成色整体较高，平均为894。共发现了五种与自然金共生的碲化物，分别是辉碲铋矿、碲铋矿、碲银矿、碲铋银矿和碲镍矿，其中辉碲铋矿含量最多。通过矿物共生组合研究及物理化学条件分析，确定成矿流体的碲逸度范围为-12.6 < logfTe2 <-9.1，硫逸度范围为-13.6 < logfS2 <-9.6。碲、铋元素的富集指示了深成幔源的信息，碲、铋等物质可能来源于古太平洋板块俯冲。玲珑金矿区大颗粒自然金的超级富集与碲、铋等元素密切相关，且银碲化物的产出提高了自然金的成色。;Jiaodong gold province has proved gold reserves of more than 5000t, which is the most important gold concentration area in China. Linglong gold district is located in the northern section of Zhao-Ping fault in the northwest of Jiaodong Peninsula, and it has the typical characteristics of a gold-bearing quartz vein deposit. Some of the ore sections in this mining area produce tellurium-bismuth enriched gold ore, therefore, it is an ideal object to study the relationship of the genesis of ore deposits and the extreme enrichment mechanism of gold with the enriched tellurium-bismuth. Through microscopic observation, scanning electron microscope analysis (SEM) and electron probe micro-analysis (EPMA), the mineral assemblages and formation mechanism of tellurium-bismuth enriched gold ore in Linglong gold district were studied in detail for the first time. The gold minerals in Linglong mining area are mainly silver-bearing native gold, and the gold fineness is high with an average of 894. Five kinds of tellurides co-occurring with native gold have been found, namely, tetradymite, tellurobismuthite, hessite, volynskite and melonite, among which the tetradymite is the most abundant. According to the study of mineral assemblages and analysis of physical and chemical conditions, the range of tellurium fugacity in the ore-forming fluid is determined to be -12.6 < logfTe2 < -9.1, while the sulfur fugacity range of -13.6 < logfS2 < -9.6. The enrichment of tellurium and bismuth indicates they are formed by a deep mantle source, and to be more specifically, the tellurium and bismuth may have been derived from the subduction of the paleo-Pacific plate. The rich concentration of large grains of native gold in Linglong gold district is closely related to tellurium and bismuth, and the precipitation of silver telluride improves the fineness of native gold.
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