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1Spatial distribution and pollution assessment of heavy metals in urban soils from southwest China显示文摘To identify the concentrations and sources of heavy metals, and to assess soil environmental quality, 63 soil samples were collected in Yibin City, Sichuan Province, China. Mean concentrations of As, Pb, Zn, and Cu were 10.55, 61.23, 138.88 and 56.35 mg/kg, respectively. As concentrations were comparable to background values, while Pb, Zn, and Cu concentrations were higher than their corresponding background values. Industrial areas exhibited the highest concentrations of As, Pb, Zn, and Cu, while the lowest concentrations occurred in parks. Statistical analysis was performed and two cluster groups of metals were identified with Pb, Zn, and Cu in one group and As in the other. Spatial distribution maps indicated that Pb, Zn, and Cu were mainly controlled by anthropogenic activities, whereas As could be mainly accounted for by soil parent materials. Pollution index values of As, Pb, Zn, and Cu varied in the range of 0.24-1.93, 0.66-7.24, 0.42-4.19, and 0.62-5.25, with mean values of 0.86, 1.98, 1.61, and 1.78, respectively. The integrated pollution index (IPI) values of these metals varied from 0.82 to 3.54, with a mean of 1.6 and more than 90% of soil samples were moderately or highly contaminated with heavy metals. The spatial distribution of IPI showed that newer urban areas displayed relatively lower heavy metal contamination in comparison with older urban areas.Guanghui Guo Fengchang Wu Fazhi Xie Ruiqing Zhang 2012Journal of Environmental Sciences2012,24,3:86
2Renewable Energy Transmission by HVDC Across the Continent:System Challenges and Opportunities显示文摘Rapid development of renewable energy in China is driving a major shift in the characteristics and control requirements of the electricity grid.Since the best renewable energy resources are far away from load centers in the east and southeast,transmission over long distances is required.Over 20 high-voltage DC(HVDC)transmission lines,with a combined capacity exceeding 150 GW,are in operation or are currently under construction.This rapid expansion of new generation and transmission capacities based on power electronics starts to change the characteristics of the grid,especially in areas where they concentrate,creating new stability problems and operational challenges.New system theories and technologies are required to support the development and operation of a future grid that relies more and more on power electronics.This paper highlights the characteristics of power electronics as used in renewable energy generation and HVDC transmission systems,discusses the impacts of these power-electronics-based assets on grid stability and operational requirements,and identifies opportunities for the development of both new system theories and system technologies to support a national energy policy that emphasizes the use of clean energy.Jian Sun Mingjie Li Zhigang Zhang Tao Xu Jingbo He Haijiao Wang Guanghui Li 2017CSEE Journal of Power and Energy Systems2017,3,4:43
3Recent progresses in mangrove conservation,restoration and research in China显示文摘Aims In this paper,we highlighted some key progresses in mangrove conservation,restoration and research in China during last two decades.Methods Based on intensive literature review,we compared the distribution and areas of existing mangroves among selected provinces of China,discussed the issues associated with mangrove conservation and restoration and highlighted major progresses on mangrove research conducted by key institutions or universities in China's Mainland,Hong Kong,Taiwan and Macao.Important findings The population boom and rapid economic developments have greatly reduced mangrove areas in China since 1980s,leaving only 22700 ha mangroves in China's Mainland in 2001.Chinese government has launched a series of programs to protect mangroves since 1980s and has established mangrove ecosystems as high-priority areas for improving environmental and living resource management.During last three decades,a total of 34 natural mangrove conservation areas have been established,which accounts for 80%of the total existing mangroves areas in China.Mangrove restoration areas in China' Mainland accounted for<7%of the total mangroves areas in 2002.A great deal of research papers on Chinese mangroves has been published in international journals.However,more systematic protection strategies and active restoration measurements are still urgently needed in order to preserve these valuable resources in China.Luzhen Chen Wenqing Wang Yihui Zhang Guanghui Lin 2009Journal of Plant Ecology2009,2,2:42
4Effect of proteins,polysaccharides,and particle sizes on sludge dewaterability显示文摘Four batch experiments of hydrolysis and acidification were carried out to investigate the distributions of proteins(PN) and polysaccharides(PS) in the sludge,the PN/PS ratio,the particle sizes,and their relationship with sludge dewaterability(as determined by capillary suction time,CST) . The sludge flocs were stratified through centrifugation-and ultrasound-based method into four fractions:(1) slime,(2) loosely bound extracellular polymeric substances(LB-EPS) ,(3) tightly bound EPS(TB-EPS) ,and(4) pellet. The results showed that PN was mainly partitioned in the pellet(80.7%) and TB-EPS(9.6%) fractions,while PS distributed evenly in the four fractions. During hydrolysis and acidification,PN was transferred from the pellet and TB-EPS fractions to the slime fraction,but PS had no significant transfer trends. The mean particle sizes of the sludge flocs decreased with hydrolysis and acidification. The pH had a more significant influence on the dewaterability of sludge flocs than temperature. Sludge dewaterability during hydrolysis and acidification processes greatly deteriorated from 9.7 s at raw sludge to 340-450 s under alkaline conditions. However,it was just slightly increased under acidic conditions. Further investigation suggested that CST was affected by soluble PN,soluble PN/PS,and particle sizes of sludge flocs,but was affected slightly by total PN,PS,or PN/PS in the whole sludge flocs and other fractions(except slime) .SHAO Liming,HE Peipei,YU Guanghui,HE Pinjing State Key Laboratory of Pollution Control and Resources Reuse,Key Laboratory of Yangtze River Water Environment,College of Environmental Science and Engineering,Tongji University,Shanghai 200092,China 2009Journal of Environmental Sciences2009,21,1:37
5Urine-derived stem cells:A novel and versatile progenitor source for cell-based therapy and regenerative medicine显示文摘Engineered functional organs or tissues,created with autologous somatic cells and seeded on biodegradable or hydrogel scaffolds,have been developed for use in individualswith tissue damage suffered fromcongenital disorders,infection,irradiation,or cancer.However,in those patients,abnormal cells obtained by biopsy fromthe compromised tissue could potentially contaminate the engineered tissues.Thus,an alternative cell source for construction of the neo-organ or functional recovery of the injured or diseased tissues would be useful.Recently,we have found stem cells existing in the urine.These cells are highly expandable,and have self-renewal capacity,paracrine properties,and multi-differentiation potential.As a novel cell source,urine-derived stem cells(USCs)provide advantages for cell therapy and tissue engineering applications in regeneration of various tissues,particularly in the genitourinary tract,because they originate from the urinary tract system.Importantly,USCs can be obtained via a non-invasive,simple,and low-cost approach and induced with high efficiency to differentiate into three dermal cell lineages.Deying Zhang Guanghui Wei Peng Li Xiaobo Zhou Yuanyuan Zhang 2014Genes & Diseases2014,1,1:34
6Effects of ultrasonic pretreatment on sludge dewaterability and extracellular polymeric substances distribution in mesophilic anaerobic digestion显示文摘Effect of ultrasonic pretreatment on sludge dewaterability was determined and the fate of extracellular polymeric substances (EPS) matrix in mesophilic anaerobic digestion after ultrasonic pretreatment was studied. Characteristics of proteins (PN), polysaccharides (PS), excitation-emission matrix (EEM) fluorescence spectroscopy and molecular weight (MW) distribution of dissolved organic matters (DOM) in different EPS fractions were evaluated. The results showed that after ultrasonic pretreatment, the normalized capillary suction time (CST) decreased from 44.4 to 11.1 (sec·L)/g total suspended solids (TSS) during anaerobic digestion, indicating that sludge dewaterability was greatly improved. The normalized CST was significantly correlated with PN concentration (R2 = 0.92, p < 0.01) and the PN/PS ratio (R2 = 0.84, p < 0.01) in the loosely bound EPS (LB-EPS) fraction. Meanwhile, the average MW of DOM in the LB- EPS and tightly bound EPS (TB-EPS) fractions also had a good correlation with the normalized CST (R2 > 0.66, p < 0.01). According to EEM fluorescence spectroscopy, tryptophan-like substances intensities in the slime, LB-EPS and TB-EPS fractions were correlated with the normalized CST. The organic matters in the EPS matrix played an important role in influencing sludge dewaterability.Liming Shao Guanzhao Wang Huacheng Xu Guanghui Yu Pinjing He 2010Journal of Environmental Sciences2010,22,3:29
7Exploring the history of cultural exchange in prehistoric Eurasia from the perspectives of crop diffusion and consumption显示文摘The history of cultural exchange in prehistoric Eurasia(CEPE) has been widely investigated. Based on archaeological evidence, this process is thought to date back to at least the early Bronze Age, although details about timings and routes remain unclear. It is likely that CEPE promoted the spread and exchange of crops that originated in different parts of Eurasia; since these remains can be definitely identified and directly dated, they provide ideal research materials to explore the history of CEPE. In this paper, we review the available archaeobotanical evidence and direct radiocarbon dates for crop remains, alongside carbon isotopic data from human bones unearthed from prehistoric sites in Eurasia, in order to investigate the history of the spread of millet crops, and wheat and barley, that were first domesticated in the eastern and western parts of Eurasia during prehistoric times.In combination with other archaeological evidences, we discuss the history of CEPE. Our results suggest that wheat and barley were domesticated in western Asia around 10500 a BP, spread into Europe and western Central Asia before 8000 a BP, and reaching eastern Central Asia and northwestern China between 4500 and 4000 a BP. Data show that both broomcorn and foxtail millet were domesticated in eastern Asia before 7700 a BP, spread into eastern Central Asia between 4500 and 4000 a BP, and into western Asia and Europe prior to 3500 a BP. Wheat, barley, and millet crops were first utilized together in eastern Kazakhstan within Central Asia around 4400 a BP, the region where earliest CEPE is likely to have taken place. These crops were mixedly used mainly in eastern central Asia and northwest China between 4500 and 3500 a BP, and then across the Eurasia before 2200 a BP. The results of this study suggest that transcontinental CEPE might have been initiated during the fifth millennium, before intensifying during the Bronze Age to lay the foundations for the creation of the ancient Silk Road during the Han Dynasty(between 202 BC and 220AD).DONG GuangHui YANG YiShi HAN JianYe WANG Hui CHEN FaHu 2017Science China Earth Sciences2017,60,6:30
8The Dominant Glutamic Acid Metabolic Flux to Produce γ-Amino Butyric Acid over Proline in Nicotiana tabacum Leaves under Water Stress Relates to its Significant Role in Antioxidant Activity显示文摘γ-Amino butyric acid (GABA) and proline play a crucial role in protecting plants during various environmental stresses. Their synthesis is from the common precursor glutamic acid, which is catalyzed by glutamate decarboxylase and △1-pyrroline-5-carboxylate synthetase respectively. However, the dominant pathway under water stress has not yet been established. To explore this, excised tobacco leaves were used to simulate a water-stress condition. The results showed GABA content was much higher than that of proline in leaves under water-deficit and non-water-deficit conditions. Specifically, the amount of GABA significantly increased compared to proline under continuous water loss for 16 h, indicating that GABA biosynthesis is the dominant pathway from glutamic acid metabolism under these conditions. Quantitative reverse transcription polymerase chain reaction and protein Western gel-blot analysis further confirmed this. To explore the function of GABA accumulation, a system producing superoxide anion (O 2 - ), peroxide hydrogen (H 2 O 2 ), and singlet oxygen ( 1 O 2 ) was employed to investigate the scavenging role on free-radical production. The results demonstrated that the scavenging ability of GABA for O 2 - , H 2 O 2 , and 1 O 2 was significantly higher than that of proline. This indicated that GABA acts as an effective osmolyte to reduce the production of reactive oxygen species under water stress.Cuili Liu Li Zhao Guanghui Yu 2011Journal of Integrative Plant Biology2011,53,8:27
9Effect of specimen size on energy dissipation characteristics of red sandstone under high strain rate显示文摘In this experiment, red sandstone specimens, having slenderness ratios of 0.5, 0.7, 0.9 and 1.1 respectively, were subjected to blow tests using a Split Hopkinson Pressure Bar(SHPB) system at a pressure of 0.4 atmospheres. In this paper, we have analyzed the effect of slenderness ratio on the mechanical properties and energy dissipation characteristics of red sandstone under high strain rates. The processes of compaction, elastic deformation and stress softening deformation of specimens contract with an increase in slenderness ratio, whilst the nonlinear deformation process extends correspondingly. In addition, degrees of damage of specimens reduced gradually and the type of destruction showed a transformation trend from stretching failure towards shear failure when the slenderness ratio increased. A model of dynamic damage evolution in red sandstone was established and the parameters of the constitutive model at different ratios of length to diameter were determined. By comparison with the experimental curve, the accuracy of the model, which could reflect the stress–strain dynamic characteristics of red sandstone, was verified. From the view of energy dissipation, an increase in slenderness ratio of a specimen decreased the proportion of energy dissipation and caused a gradual fall in the capability of energy dissipation during the specimen failure process. To some extent, the study indicated the effects of slenderness ratios on the mechanical properties and energy dissipation characteristics of red sandstone under the high strain rate, which provides valuable references to related engineering designs and academic researches.Li Ming Mao Xianbiao Lu Aihong Tao Jing Zhang Guanghui Zhang Lianying Li Chong 2014International Journal of Mining Science and Technology2014,24,2:24
10Responses of soil respiration to simulated precipitation pulses in semiarid steppe under different grazing regimes显示文摘Aims Precipitation pulses and different land use practices(such as grazing)play important roles in regulating soil respiration and carbon balance of semiarid steppe ecosystems in Inner Mongolia.However,the interactive effects of grazing and rain event magnitude on soil respiration of steppe ecosystems are still unknown.We conducted a manipulative experiment with simulated precipitation pulses in Inner Mongolia steppe to study the possible responses of soil respiration to different precipitation pulse sizes and to examine how grazing may affect the responses of soil respiration to precipitation pulses.Methods Six water treatments with different precipitation pulse sizes(0,5,10,25,50 and 100 mm)were conducted in the ungrazed and grazed sites,respectively.Variation patterns of soil respiration of each treatment were determined continuously after the water addition treatments.Important Findings Rapid and substantial increases in soil respiration occurred 1 day after the water treatments in both sites,and the magnitude and duration of the increase in soil respiration depended on pulse size.Significantly positive relationships between the soil respiration and soil moisture in both sites suggested that soil moisture was the most important factor responsible for soil respiration rate during rain pulse events.The ungrazed site maintained significantly higher soil moisture for a longer time,which was the reason that the soil respiration in the ungrazed site was maintained relatively higher rate and longer period than that in the grazed site after a rain event.The significant exponential relationship between soil temperature and soil respiration was found only in the plots with the high water addition treatments(50 and 100 mm).Lower capacity of soil water holding and lower temperature sensitivity of soil respiration in the grazed site indicated that degraded steppe due to grazing might release less CO_(2) to the atmosphere through soil respiration under future precipitation and temperature scenarios.Shiping Chen Guanghui Lin Jianhui Huang Mao He 2008Journal of Plant Ecology2008,1,4:24
11Neighbor sum distinguishing total colorings of K4-minor free graphs显示文摘一个总数[k ] 图 G 的着色是印射:V (G) E (G){ 1, 2,, k } 以便在 V (G) E (G) 的任何二个邻近的元素收到不同颜色。让 f (v) 表示顶点 v 的颜色和 v 的所有事件边的颜色的和。一个总数[k ] G 的邻居和区分着色是一个总数[k ] G 的着色以便为每边 uv E (G) , f (u) f (v) 。由 nsd,我们在 G 的如此的着色表示最小的价值 k。Pilniak 和 Woniak 与最大的度(G) 为任何简单的图推测了 nsd (G)(G)+3。这推测为完全的图,周期,由两部组成的图,和 subcubic 图被证明了。在这份报纸,我们证明它也为 K 4 未成年者保持免费的图。而且,我们看那 G 是否是一个 K 4 未成年者有(G) 的免费的图 4,然后 gc nsd (G)(G)+ 2。2 突然地是的界限(G)+ 。Hualong LI Bingqiang LIU Guanghui WANG 2013Frontiers of Mathematics in China2013,8,6:23
12Whole-Genome Sequencing and Analysis of the Chinese Herbal Plant Panax notoginseng显示文摘Wei Chen Ling Kui Guanghui Zhang Shusheng Zhu Jing Zhang Xiao Wang Min Yang Huichuan Huang Yixiang Liu Yong Wang Yahe Li Lipin Zeng Wen Wang Xiahong He Yang Dong Shengchao Yang 2017Molecular Plant2017,10,6:21
13An aerospace bracket designed by thermo-elastic topology optimization and manufactured by additive manufacturing显示文摘Combination of topology optimization and additive manufacturing technologies provides an effective approach for the development of light-weight and high-performance structures.A heavy-loaded aerospace bracket is designed by topology optimization and manufactured by additive manufacturing technology in this work.Considering both mechanical forces and temperature loads,a formulation of thermo-elastic topology optimization is firstly proposed and the sensitivity analysis is derived in detail.Then the procedure of numerical optimization design is presented and the final design is additively manufactured using Selective Laser Melting(SLM).The mass of the aerospace bracket is reduced by over 18%,benefiting from topology and size optimization,and the three constraints are satisfied as well in the final design.This work indicates that the integration of thermo-elastic topology optimization and additive manufacturing technologies can be a rather powerful tool kit for the design of structures under thermal-mechanical loading.Guanghui SHI Chengqi GUAN Dongliang QUAN Dongtao WU Lei TANG Tong GAO 2020Chinese Journal of Aeronautics2020,33,4:21
14History and possible mechanisms of prehistoric human migration to the Tibetan Plateau显示文摘Prehistoric human history on the Tibetan Plateau is a hotly debated topic. Archaeological research on the plateau during the past few decades has enormously improved our understanding of the topic and makes it possible for us to consider the processes and mechanisms of prehistoric human migration to the region. By reviewing the published archaeological research on the Tibetan Plateau, we propose that the first people on the plateau initially spread into the He-Huang region from the Chinese Loess Plateau, and then moved to the low elevation Northeastern Tibetan Plateau and perhaps subsequently to the entire plateau. This process consisted of four stages.(1) During the climatic amelioration of the Last Deglacial period(15–11.6 ka BP), Upper Paleolithic hunter-gatherers with a developed microlithic technology first spread into the Northeastern Tibetan Plateau.(2) In the early-mid Holocene(11.6–6 ka BP), Epipaleolithic microlithic hunter-gatherers were widely distributed on the northeastern plateau and spread southwards to the interior plateau, possibly with millet agriculture developed in the neighboring low elevation regions.(3) In the mid-late Holocene(6–4 ka BP), Neolithic millet farmers spread into low elevation river valleys in the northeastern and southeastern plateau areas.(4) In the late Holocene(4–2.3 ka BP), Bronze Age barley and wheat farmers further settled on the high elevation regions of the Tibetan Plateau, especially after 3.6 ka BP. Finally, we suggest that all of the reported Paleolithic sites earlier than the LGM on the Tibetan Plateau need further examination.ZHANG DongJu DONG GuangHui WANG Hui REN XiaoYan HA PiPu'u QIANG MingRui CHEN FaHui 2016Science China Earth Sciences2016,59,9:20
15Identification of coastal wetlands of international importance for waterbirds:a review of China Coastal Waterbird Surveys 2005–2013显示文摘Background:China's coastal wetlands belong to some of the most threatened ecosystems worldwide.The loss and degradation of these wetlands seriously threaten waterbirds that depend on wetlands.Methods:The China Coastal Waterbird Census was organized by volunteer birdwatchers in China's coastal region.Waterbirds were surveyed synchronously once every month at 14 sites,as well as irregularly at a further 18 sites,between September 2005 and December 2013.Results:A total of 75 species of waterbirds met the 1 % population level Ramsar listing criterion at least once at one site.The number of birds of the following species accounted for over 20 % of the total flyway populations at a single site:Mute Swan(Cygnus olor),Siberia Crane(Grus leucogeranus),Far Eastern Oystercatcher(Haematopus osculans),Bar-tailed Godwit(Limosa lapponica),Spotted Greenshank(Tringa guttifer),Great Knot(Calidris tenuirostris),Spoon-billed Sandpiper(Calidris pygmeus),Saunders' s Gull(Larus saundersi),Relict Gull(Larus relictus),Great Cormorant(Phalacrocorax carbo),Eurasian Spoonbill(Platalea leucorodia),Black-faced Spoonbill(Platalea minor) and Dalmatian Pelican(Pelecanus crispus).A total of 26 sites supported at least one species of which their number met the1 % criterion.Forty-two species met the 1 % criterion in the Yellow River Delta,Shandong;29 at the Cangzhou coast,Hebei and 26 species at the Lianyungang coast,Jiangsu.Conclusions:The results highlight the international importance of China's coastal wetlands for waterbirds.This study also demonstrates that participation of local birdwatchers in waterbird surveys results in data that are invaluable not only for understanding the current status of waterbirds in China's coastal regions but also for waterbird conservation and management.Qingquan Bai Jianzhong Chen Zhihong Chen Guotai Dong Jiangtian Dong Wenxiao Dong Vivian Wing Kan Fu Yongxiang Han Gang Lu Jing Li Yang Liu Zhi Lin Derong Meng Jonathan Martinez Guanghui Ni Kai Shan Renjie Sun Suixing Tian Fengqin Wang Zhiwei Xu Yat-tung Yu Jin Yang Zhidong Yang Lin Zhang Ming Zhang Xiangwu Zeng 2015Chinese Birds2015,,3:20
16Thermal energy storage:Challenges and the role of particle technology显示文摘Thermal energy is at the heart of the whole energy chain providing a main linkage between the primary and secondary energy sources.Thermal energy storage(TES)has a pivotal role to play in the energy chain and hence in future low carbon economy.However,a competitive TES technology requires a number of scientific and technological challenges to be addressed including TES materials,TES components and devices,and integration of TES devices with energy networks and associated dynamic optimization.This paper provides a perspective of TES technology with a focus on TES materials challenges using molten salts based phase change materials for medium and high temperature applications.Two key challenges for the molten salt based TES materials are chemical incompatibility and low thermal conductivity.The use of composite materials provides an avenue to meeting the challenges.Such composite materials consist of a phase change material,a structural supporting material,and a thermal conductivity enhancement material.The properties of the supporting material could determine the dispersion of the thermal conductivity enhancement material in the salt.A right combination of the salt,the structural supporting material,and the thermal conductivity enhancement material could give a hierarchical structure that is able to encapsulate the molten salt and give a substantial enhancement in the thermal conductivity.Understanding of the structure-property relationships for the composite is essential for the formulation design and fabrication of the composite materials.Linking materials properties to the system level performance is recommended as a key future direction of research.Zhiwei Ge Yongliang Li Dacheng Li Ze Sun Yi Jin Chuanping Liu Chuan Li Guanghui Leng Yulong Ding 2014Particuology2014,12,4:20
17Carbonate-salt-based composite materials for medium- and high-temperature thermal energy storage显示文摘This paper discusses composite materials based on inorganic salts for medium- and high-temperature thermal energy storage application.The composites consist of a phase change material(PCM),a ceramic material,and a high thermal conductivity material.The ceramic material forms a microstructural skeleton for encapsulation of the PCM and structural stability of the composites;the high thermal conductivity material enhances the overall thermal conductivity of the composites.Using a eutectic salt of lithium and sodium carbonates as the PCM,magnesium oxide as the ceramic skeleton,and either graphite flakes or carbon nanotubes as the thermal conductivity enhancer,we produced composites with good physical and chemical stability and high thermal conductivity.We found that the wettability of the molten salt on the ceramic and carbon materials significantly affects the microstructure of the composites.Zhiwei Ge Feng Ye Hui Cao Guanghui Leng Yue Qin Yulong Ding 2014Particuology2014,12,4:19
18The Dihedral Angle and Intersection Processes of a Conjugate Strike-Slip Fault System in the Tarim Basin, NW China显示文摘Recent studies, focused on dihedral angles and intersection processes, have increased understandings of conjugate fault mechanisms. We present new 3-D seismic data and microstructural core analysis in a case study of a large conjugate strike-slip fault system from the intracratonic Tarim Basin, NW China. Within our study area, 'X' type NE and NW trending faults occur within CambrianOrdovician carbonates. The dihedral angles of these conjugate faults have narrow ranges, 19° to 62° in the Cambrian and 26° to 51° in the Ordovician, and their modes are 42° and 44° respectively. These data are significantly different from the ~60° predicted by the Coulomb fracture criterion. It is concluded that:(1) The dihedral angles of the conjugate faults were not controlled by confining pressure, which was low and associated with shallow burial;(2) As dihedral angles were not controlled by pressure they can be used to determine the shortening direction during faulting;(3) Sequential slip may have played an important role in forming conjugate fault intersections;(4) The conjugate fault system of the Tarim basin initiated as rhombic joints; these subsequently developed into sequentially active 'X' type conjugate faults; followed by preferential development of the NW-trending faults; then reactivation of the NE trending faults. This intact rhombic conjugate fault system presents new insights into mechanisms of dihedral angle development, with particular relevance to intracratonic basins.WU Guanghui YUAN Yajuan HUANG Shaoying Thomas Matthew Vandyk XIAO Yang CAI Quan LUO Bingxu 2018Acta Geologica Sinica(English Edition)2018,92,1:19
19On the timing of the East Asian summer monsoon maximum during the Holocene Does the speleothem oxygen isotope record reflect monsoon rainfall variability?显示文摘The evolution of the East Asian summer monsoon(EASM) during the Holocene has long been of significant interest.Knowledge of past EASM variability not only increases our understanding of monsoon dynamics on a long timescale,but it also provides an environmental and climatic background for research into Chinese cultural development.However,the timing of the EASM maximum remains controversial.The popular concept of an 'early Holocene maximum' is mainly based on speleothemδ^(18)O(δ^(18)O_c) records from caves in southern China;however,the interpretation of δ^(18)O_C as a reliable proxy for EASM intensity is being increasingly challenged.The present paper is a critical review of the climatic significance of the δ^(18)O_C record from China.Firstly,we suggest that precipitation in northern China is an appropriate index of EASM intensity,the variation of which clearly indicates a mid-Holocene monsoon maximum.Secondly,an interregional comparison demonstrates that the precipitation record in northern China is quite different from that in southern China on a range of timescales,and is inconsistent with the spatial similarity exhibited by speleothem oxygen isotope records.Furthermore,both modeling and observational data show that the δ^(18)O_C records from southern China indeed reflect changes in precipitation δ^(18)O(δ^(18)O_P) rather than precipitation amount,and therefore that their use as an EASM proxy is inappropriate.Finally,we address several significant monsoon-related issues-including the driving mechanism of the EASM on an orbital timescale,the climatic significance of speleothem oxygen isotopes,and the relationship between atmospheric circulation and precipitation in monsoonal regions.CHEN JianHui RAO ZhiGuo LIU JianBao HUANG Wei FENG Song DONG GuangHui HU Yu XU QingHai CHEN FaHu 2016Science China(Information Sciences)2016,59,12:18
20Characteristics and origin of abnormally high porosity zones in buried Paleogene clastic reservoirs in the Shengtuo area, Dongying Sag, East China显示文摘There are three abnormally high porosity zones developed in buried Paleogene nearshore subaqueous fan and sublacustrine fan clastic reservoirs at 2,800-3,200 m, 3,250-3,700 m and 3,900-4,400 m, respectively, within the Shengtuo area of the Dongying Sag. Here the porosity of reservoirs buried deeper than 4,000 m can still be greater than 20%. Investigation of these three abnormally high porosity(AHP) zones in the 3rd to 4th member of the Paleogene Shahejie Formation in the Shengtuo area was carried out with utilization of core observation, thin section identification, SEM observation, image analysis, core physical property testing and other technical methods. The results show that, the AHP zones in 2,800-3,200 m and 3,250-3,700 m are visible pores primary AHP zones dominated by significant primary intergranular pores(more than 50% of the total porosity), while secondary pores and micropores in authigenic clays may develop in some reservoirs. AHP reservoirs in the AHP zone of 3,900-4,400 m are dominated by micropores in matrix, visible pores are mainly grain dissolution pores but with low absolute content(< 1%), so this zone belongs to the micropores primary AHP zone. The genesis of the three AHP zones was studied to distinguish between porosity enhancement and porosity preservation. Our research shows that, in deeply buried clastic reservoirs in the Shengtuo area, mineral dissolution occurred in a relatively closed diagenetic system with high temperature and high salinity. Reservoir rocks underwent extensive feldspar dissolution, while detrital carbonate grains and carbonate cements show no evidence of extensive dissolution. Although significant feldspar dissolution pores developed, feldspar dissolution enhanced porosity only a little due to the precipitation of almost isovolumetric dissolution products in the nearby primary intergranular pores in forms of authigenic clays and quartz cements. Net enhanced porosity originating from feldspar dissolution is generally less than 0.25%. Thus, the subsurface dissolution has little impact on the mid-deep buried high porosity reservoirs. Reservoirs in braided channels of middle fans in sublacustrine fans and reservoirs in the middle-front of fan bodies of nearshore subaqueous fans provide the basis for the development of AHP zones. The shallow development of fluid overpressure and early hydrocarbon emplacement have effectively retarded compaction and carbonate cementation, so that the high porosity in the superficial layers is preserved in the mid-deep layers. These are the main controlling factors in the development of AHP zones.Cao Yingchang Yuan Guanghui Li Xiaoyan Wang Yanzhong Xi Kelai Wang Xiaoming Jia Zhenzhen Yang Tian 2014Petroleum Science2014,11,3:18
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