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36 result(s) for "南方地区"
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鼻咽、肺双原发癌一例病例报告和文献复习
肺癌是世界范围内最常见的肿瘤之一,在我国的发病率约为62.1/100000。鼻咽癌则是我国南方地区常见的肿瘤,在上述流行区其发病率在10-30/100000之间。肺是鼻咽癌远处转移的主要部位之一,仅是存在单纯肺转移的患者就占所有晚期患者的16%。因此在流行区内,对于鼻咽癌患者在治疗或随访过程中合并出现肺部肿物者,常常需要与原发性肺癌进行鉴别。
A comparison study of tungsten-bearing granite and related mineralization in the northern Jiangxi-southern Anhui provinces and southern Jiangxi Province in South China
The southern Jiangxi Province (SJP) and northern Jiangxi-southern Anhui provinces (NJSAP) are the two most important tungsten metallogenic districts in South China. The SJP district is a well-known tungsten producer in South China where distributes several ore concentrated areas such as the "Chongyi-Dayu-Shangyou", "Yudu" and "Longnan-Quanan-Dingnan" areas, with many large and super large tungsten deposits including the famous Xihuashan, Piaotang, Pangushan and Dajishan deposits. In recent years, major prospecting breakthrough for W-polymetallic resources has been made in the NJSAP district. Several large and super large W-Cu (Mo) deposits, such as the Dahutang, Zhuxi, Dongyuan and Baizhangyan deposits, are discovered. These deposits are all genetically associated with the Yanshanian (Mesozoic) granitic magmatism. In this study, a systematic comparison of the temporal and spatial distribution, petrology, geochronology, and geochemical characteristics of the tungsten-bearing granites between the SJP and NJSAP districts has been made, with an aim to improving the understanding of the petrogenesis of the granites and associated metal enrichment mechanisms in the two tungsten ore districts in South China. The following conclusions can be drawn: (1) The ages of the tungsten-bearing granites and associated mineralization are different in the two districts, in the SJP district the ages are mainly concentrated in 165-150 Ma, whereas in the NJSAP district it displays two age periods, one is 150-140 Ma (Late Jurassic-Early Cretaceous), and the other is 135-120 Ma (Early Cretaceous). (2) The tungsten-bearing granites from both the NJSAP and SJP districts are highly fractionated granitic rocks, but the SJP granites have experienced higher degree of fractional crystallization and more extensive fluid metasomatism than the NJSAP granites. (3) The petrogeneses of the tungsten-bearing granites from the two districts are different, those from the NJSAP district originated from partial melting of less mature sandstone-mudstone intercalated with meta-volcanic rocks of the Neoproterozoic Shuangqiaoshan Group which are both W and Cu enriched, in contrast those from the SJP district were likely derived from the highly mature, clay-rich mudstones of the Mesoproterozoic age which are only W enriched. In summary, the different source rocks with different metal enrichment features and different magmatic evolution and fractional degrees for the granites in the two districts might be the key factors that controlled the different matallogenic characteristics of tungsten ore deposits in the two districts in South China.
Urban expansion in China and its effect on cultivated land before and after initiating "Reform and Open Policy
Urbanization in China has expanded at an unprecedented speed since the declaration of "Reform and Open Policy" and presented many challenges. Unbalanced regional development, appearance of super megacities and concomitant problems, and conflicts between urbanization and cultivated land protection are three critical problems that Chinese urbanization has to face. To develop new plans for foreseeable future urbanization in China, it is critical to understand the evolving history of cities across China. This study maps urban expansion of 60 typical Chinese cities based on large amount of remote sensing data and the labor-intensive image interpretation method, in order to understand the history of urban expansion from the 1970s to 2013. Results showed that area of cities expanded 5.23 times compared to their area in the 1970s. Urban expansion in China accelerated three times (1988-1996, 1999-2006, and 2009-2011) and decelerated three times (1997-1998, 2007-2008, and 2012-2013) over the 40 years. The urban area of South China expanded most significantly 9.42 times, while the urban area in Northeast China expanded only 2.37 times. The disparity among different administrative ranks of cities was even greater than (3.81 times) the differences among different regions. Super megacities have been continuously expanding at a fast rate (8.60-fold), and have not shown obvious signs of slowing down. The proportion of cultivated land among the land sources for urban expansion decreased to a small extent in the 1990s, but cultivated land continues to be the major land source for urban expansion. Effective future urbanization needs controlling the expansion scale of large cities and reasonably developing medium and small cities, as well as balancing regional development.
Diversity of Mesozoic tin-bearing granites in the Nanling and adjacent regions, South China: Distinctive mineralogical patterns
The Nanling and adjacent regions of South China host a series of tin deposits related to Mesozoic granites with diverse petrological characteristics. The rocks are amphibole-bearing biotite granites, or (topaz-) albite-lepidolite (zinnwaldite) granites, and geochemically correspond to mealuminous and peraluminous types, respectively. Mineralogical studies demonstrate highly distinctive and critical patterns for each type of granites. In mealuminous tin granites amphibole, biotite and perthite are the typical rock-forming mineral association; titanite and magnetite are typical accessory minerals, indicating highjO2 magmatic conditions; cassiterite, biotite and titanite are the principal Sn-bearing minerals; and pure cassiterite has low trace-element contents. However, in peraluminous tin granites zirmwaldite-lepidolite, K-feldspar and albite are typical rock-forming minerals; topaz is a common accessory phase, indicative of high peraluminity of this type of granites; cassiterite is present as a uniquely important tin mineral, typically rich in Nb and Ta. Mineralogical distinction between the two types of tin granites is largely controlled by redox state, volatile content and differentiation of magmatic melts. In oxidized metaluminous granitic melts, Sn4+ is readily concentrated in Ti-bearing rock-forming and accessory minerals. Such Sn-bearing minerals are typical of oxidized tin granites, and are enriched in granites at the late fractionation stage. In relatively reduced peraluminous granitic melts, Sn2+ is not readily incorporated into rock-forming and accessory minerals, except for cassiterite at fractionation stage of granite magma, which serves as an indicator of tin mineralization associated with this type of granites. The nature of magma and the geochemical behavior of tin in the two types of granites thus result in the formation of different types of tin deposits. Metaluminous granites host disseminated tin mineralization, and are locally related to deposits of the chlorite quartz-vein, greisen, and skarn types. Greisen, skarn, and quartz-vein tin deposits can occur related to peraluminous granites, but disseminated mineralization of cassiterite is more typical.
Adakitic rocks associated with the Shilu copper–molybdenum deposit in the Yangchun Basin,South China,and their tectonic implications
South China is famous for the extensive magmatism and polymetallic mineralization that took place there in the Mesozoic. Shilu is a large porphyry–skarn Cu–Mo deposit in the Yangchun Basin, South China. The lithology of the Shilu intrusion is granodiorite and quartz diorite, both of which are high-K calc-alkaline series, with high Sr([400 ppm) content along with low Y and Yb contents. Most of the samples have characteristics of adakite except for a few samples that have slightly higher Y and Yb contents, which may be plausibly explained by crustal contamination. Laser Ablation Inductively Coupled Plasma Mass Spectrometry zircon U–Pb dating revealed ages between 106.6 ± 1.3 and 103.9 ± 0.5 Ma, with multiple magmatic pulses. Molybdenite Re–Os isochron age of 102.2 ± 2.9 Ma(MSWD = 9.4) was determined, which is identical to the youngest zircon U–Pb age(103.9 ± 0.5 Ma) within error.The Shilu intrusion has high oxygen fugacity as indicated by high zircon Ce^4+/Ce^3+ and EuN/EuN^* ratios. Considering the geochemical characteristics(high Sr, and low Y and Yb contents), high oxygen fugacity, and copper mineralization of the Shilu intrusion, it was most likely formed by partial melting of a subducted young oceanic slab. Whole-rock Sr–Nd isotope-, zircon Hf isotope-, and whole-rock trace element analyses show that Shilu adakitic magmas may have interacted with type II enriched mantle and/or crustal materials during ascent. South China was affected by the Pacific tectonic regime to the east and the Neo-Tethys tectonic regime to the south in the Cretaceous. Based on the Pacific Plate drifting and rotation history, it is hard to explain how the Pacific Plate would have subducted and melted, forming adakitic rocks in the Shilu region. Considering the tectonic history of Southeast Asia and the South China Sea, the Neo-Tethys trench should have been much closer to the South China Block in the Cretaceous, and thus have had a greater impact on the South China Block. Based on the subduction direction, time of subduction,and distance between the Neo-Tethys subduction zone and the Shilu deposit, subduction of the Neo-Tethys ridge is the best mechanism for explaining the Shilu adakitic rocks and Cu–Mo mineralization.
Effects of future land use change on the regional climate in China
Land use and land cover change (LUCC) is one of the important human forcing on climate. However, it is difficult to infer how LUCC will affect climate in the future from the effects of previous LUCC on regional climates in the past. Thus, based on the land cover data recommended by the Coupled Model Intercomparison Project Phase 5 (CMIP5), a regional climate model (RegCM4) was used to investigate the climate effects of future land use change over China. Two 15-year simulations (2036-2050), one with the current land use data and the other with future land cover scenario (2050) were conducted. It is noted that future LUCC in China is mainly characterized by the transition from the grassland to the forest. Results suggest that the magnitudes and ranges of the changes in temperature and precipitation caused by future LUCC show evident seasonality, which are more prominent in summer and autumn. Significant response of climate to future LUCC mainly happens in Northeast China, North China, the Hetao Area, Eastern Qinghai-Tibetan Plateau and South China. Further investigation shows that future LUCC can also produce significant impacts on the atmospheric circulation. LUCC results in abnormal southwesterly wind over extensive areas from the Indian peninsula to the coasts of the South China Sea and South China through the Bay of Bengal. Furthermore, Indian tropical southwest monsoons and South Sea southwest monsoons will both be strong, and the ab- normal water vapor convergence from the South China Sea and the Indian Ocean will result in more precipitation in South China.
Assimilating Doppler radar observations with an ensemble Kalman filter for convection-permitting prediction of convective development in a heavy rainfall event during the pre-summer rainy season of South China
This study examines the effectiveness of an ensemble Kalman filter based on the weather research and forecasting model to assimilate Doppler-radar radial-velocity observations for convection-permitting prediction of convection evolution in a high-impact heavy-rainfall event over coastal areas of South China during the pre-summer rainy season. An ensemble of 40 deterministic forecast experiments(40 DADF) with data assimilation(DA) is conducted, in which the DA starts at the same time but lasts for different time spans(up to 2 h) and with different time intervals of 6, 12, 24, and 30 min. The reference experiment is conducted without DA(NODA).To show more clearly the impact of radar DA on mesoscale convective system(MCS)forecasts, two sets of 60-member ensemble experiments(NODA EF and exp37 EF) are performed using the same 60-member perturbed-ensemble initial fields but with the radar DA being conducted every 6 min in the exp37 EF experiments from 0200 to0400 BST. It is found that the DA experiments generally improve the convection prediction. The 40 DADF experiments can forecast a heavy-rain-producing MCS over land and an MCS over the ocean with high probability, despite slight displacement errors. The exp37 EF improves the probability forecast of inland and offshore MCSs more than does NODA EF. Compared with the experiments using the longer DA time intervals, assimilating the radial-velocity observations at 6-min intervals tends to produce better forecasts. The experiment with the longest DA time span and shortest time interval shows the best performance.However, a shorter DA time interval(e.g., 12 min) or a longer DA time span does not always help. The experiment with the shortest DA time interval and maximum DA window shows the best performance, as it corrects errors in the simulated convection evolution over both the inland and offshore areas. An improved representation of the initial state leads to dynamic and thermodynamic conditions that are more conducive to earlier initiation of the inland MCS and longer maintenance of the offshore MCS.
Crustal stress field in Yunnan: implication for crust-mantle coupling
We applied the g CAP algorithm to determine 239 focal mechanism solutions 3:0≤MW≤ 6:0) with records of dense Chin Array stations deployed in Yunnan,and then inverted 686 focal mechanisms(including 447 previous results) for the regional crustal stress field with a damped linear inversion. The results indicate dominantly strike-slip environment in Yunnan as both the maximum(r1) and minimum(r3) principal stress axes are sub-horizontal. We further calculated the horizontal stress orientations(i.e., maximum and minimum horizontal compressive stress axes: S H and S h, respectively) accordingly and found an abrupt change near *26°N. To the north, S H aligns NW-SE to nearly E-W while S h aligns nearly N-S. In contrast, to the south, both S H and S h rotate laterally and show dominantly fan-shaped patterns. The minimum horizontal stress(i.e., maximum strain axis) S h rotates from NW-SE to the west of Tengchong volcano gradually to nearly E-W in west Yunnan, and further toNE-SW in the South China block in the east. The crustal strain field is consistent with the upper mantle strain field indicated by shear-wave splitting observations in Yunnan but not in other regions. Therefore, the crust and upper mantle in Yunnan are coupled and suffering vertically coherent pure-shear deformation in the lithosphere.
Genesis of Highly Fractionated I-Type Granites from Fengshun Complex: Implications to Tectonic Evolutions of South China
The South China Block is characterized by the large-scale emplacement of felsic magmas and giant ore deposits during the Yanshanian. We present zircon Hf isotopic compositions, whole-rock major and trace element compositions of the Fengshun complex, located in eastern Guangdong Province, South China. The Fengshun complex is a multi-stage magmatic intrusion. It is composed of two main units, i.e., the Mantoushan(MTS) syeno-monzogranites, alkali feldspar granites and the Hulutian(HLT) alkali feldspar granites. LA-ICPMS zircon dating shows that the complex emplaced in 166–161 and 139±2 Ma, respectively. Geochemically, the MTS granites show relatively various geochemical compositions with low REE contents(87.76×10-6–249.71×10-6), Rb/Sr ratios(1.19–58.93), pronounced Eu negative anomaly(0.01–0.37) and low Nb/Ta ratios(2.40–6.82). In contrast, the HLT granites exhibit relatively stable geochemical characteristics with high REE contents(147.35×10-6– 282.17×10-6), Rb/Sr ratios(2.05–10.30) and relatively high Nb/Ta ratios(4.45–13.00). The isotopic data of the MTS granites display relatively enriched values, with ISr varying from 0.708 2 to 0.709 7, εNd(t) from-7.8 to-6.9 and εHf(t) from-7.4 to-3.2, in comparison with those of the HLT which are ISr=0.703 05–0.704 77, εNd(t)=-5–-3.4 and εHf(t)=-0.7–1.8). The two-stage model ages of the MTS granites(T2DM(Nd)=1.51–1.59 Ga and T2DM(Hf)=1.26–1.48 Ga) are also higher than those of the HLT granites(T2DM(Nd)=1.21–1.34 Ga and T2DM(Hf)=0.96–1.10 Ga). Thus the MTS and HLT granites might originate from different sources. The former is more likely derived from partial melting of Meso-Proterozoic basement triggered by upwelling of asthenosphere and/or underplate of the basaltic magma and then extensive fractional crystallisation, similar to the genesis of Early Yanshanian granitoids of the EW-trending tectono-magmatism belt in the Nanling range. In comparison, the latter might have involved with asthenosphere component, similar to the Early Cretaceous granitoids of NE-NNE-trending granitoid-volcanic belt in coastal region, southeastern China. We propose that the MTS granites were mainly formed in Paleo-Tethyan post-orogenic extensional tectonic setting whereas the HLT granites were formed in the back-arc extensional tectonic setting. The period at 139 Ma represents the initial time of roll-back of the paleo-Pacific Plate in SE-trending.
Process and proposal for comprehensive regionalization of Chinese human geography
The comprehensive regionalization of Chinese human geography is based on the rules governing regional differentiation of Chinese physical geographic factors. Based on regional differences and similarities in human factors, this study divides the whole country into two levels of relatively independent, complete and organically linked human geographic units. As a fundamental, comprehensive, cutting-edge, practical and important task, the comprehensive regionalization of human geography highlights the characteristics, regional and sub-regional features, complexity and variety of spatial differences between factors of Chinese human geography. It is capable of promoting the development of human geography based on local conditions, providing basic scientific support to national and local development strategies, such as the Belt and Road Strategy, new urbanization and environmental awareness, and creating a sound geopolitical environment in key areas. Using results from existing physical and human geographic zoning studies, and in accordance with the principles of synthesis, dominant factors, the relative consistency of the natural environment, the relative consistency of social and economic development, the consistency of the regional cultural landscape, the continuity of spatial distribution and the integrity of county-level administrative divisions, and taking as its basis the division of human geography into 10 major factors (nature, economy, population, culture, ethnicity, agriculture, transportation, urbanization, the settlement landscape and administrative divisions), this paper constructs an index system for the comprehensive regionalization of Chinese human geography through a combination of top-down and bottom-up zoning and spatial clustering analysis. In this study, Chinese human geography is divided into eight regions and 66 sub-regions. The eight human geography regions are (Ⅰ) Northeast China, (Ⅱ) North China, (Ⅲ) East China, (Ⅳ) Central China, (Ⅴ) South China, (Ⅵ) Northwest China, (Ⅶ) Southwest China, and (Ⅷ) Qinghai and Tibet. This zoning proposal fills gaps in studies involving the non-comprehensive regionalization of Chinese human geography. Each human geography region and sub-region has different topographical climatic, ecological, population, urbanization, economic development, settlement landscape, regional cultural and ethno-religious attributes. This proposal on the comprehensive regionalization of Chinese human geography dovetails closely with previous studies on comprehensive regionalization in Chinese physical geography, Chinese economic zoning, and Chinese agricultural zoning. It shows that, under the dual roles of nature and humans, there are certain rules of regional differentiation that govern the comprehensive regionalization of Chinese human geography.