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1Anatomy of composition and nature of plate convergence: Insights for alternative thoughts for terminal India-Eurasia collision显示文摘The pattern and timing of collision between India and Eurasia have long been a major concern of the international community. However, no consensus has been reached hitherto. To explore and resolve the disagreements in the Himalayan study,in this paper we begin with the methodology and basic principles for the anatomy of composition and nature of convergent margins,then followed by an effort to conduct a similar anatomy for the India-Eurasia collision. One of the most common patterns of plate convergence involves a passive continental margin, an active continental margin and intra-oceanic basins together with accreted terranes in between. The ultimate configuration and location of the terminal suture zone are controlled by the basal surface of the accretionary wedge, which may show fairly complex morphology with Z-shape and fluctuant geometry. One plausible method to determine the terminal suture zone is to dissect the compositions and structures of active continental margins. It requires a focus on various tectonic elements belonging to the upper plate, such as accretionary wedges, high-pressure(HP)-ultra-high-pressure(UHP) metamorphic rocks, Barrovian-type metamorphic rocks and basement nappes, together with superimposed forearc basins.Such geological records can define the extreme limits and the intervening surface separating active margin from the passive one,thus offering a general sketch for the surface trace of the terminal suture zone often with a cryptic feature. Furthermore, the occurrence of the cryptic suture zone in depth may be constrained by geophysical data, which, in combination with outcrop studies of HP-UHP metamorphic rocks, enables us to outline the terminal suture zone. The southern part of the Himalayan orogen records complicated temporal and spatial features, which are hard to be fully explained by the classic 'two-plate-one-ocean' template,therefore re-anatomy of the compositions and nature for this region is necessitated. Taking advantage of the methodology and basic principles of plate convergence anatomy and synthesizing previous studies together with our recent research, we may gain new insights into the evolution of the Himalayan orogeny.(1) The Yarlung-Zangbo ophiolite is composed of multiple tectonic units rather than a single terminal suture zone, and a group of different tectonic units were juxtaposed against each other in the backstop of the Gangdese forearc.(2) The Tethyan Himalayan Sequence(THS) contains mélanges with typical block-in-matrix structures, uniform southwards paleocurrents and age spectra of detrital zircons typical of Eurasia continent. All of these facts indicate that the THS belonged to Eurasia plate before the terminal collision, emplaced in the forearc of the Gangdese arc.(3) The Greater Himalayan Crystalline Complex(GHC) and Lesser Himalayan Sequence(LHS) comprise complex components including eclogites emplaced into the GHC and the upper part of the LHS. Judging from the fact that HP-UHP metamorphic rocks are exhumed and emplaced in the upper plate, the GHC and the upper part of the LHS where eclogite occur should be assigned to the upper plate, lying above the terminal subduction zone surface. It is the very surface along which the continuous subduction of the India subcontinent occurred, therefore acting as the terminal, cryptic suture. From the suture further southward, the bulk rock associations of the LHS and Sub-Himalayan Sequence(Siwalik) show little affinity of mélange, probably belonging to the foreland system of the India plate. By the anatomy of tectonic features of all the tectonic units in the Himalayan orogen as well as the ages of the subduction-accretion related deformation, we conclude that the terminal India-Eurasia collision occurred after 14 Ma, the timing of the metamorphism of the eclogites emplaced into the upper plate. The development of rifts stretching in N-S direction in Tibet and tectonic events with the transition from sinistral to dextral movements in shear zones, such as the Ailaoshan fault in East Tibet, can coordinately reflect the scale and geodynamic influence of the India-Eurasia convergence zone.By conducting a detailed anatomy of the southern Himalayas, we propose a new model for the final collision-accretion of the Himalayan orogeny. Our study indicates that the anatomy of structures, composition, and tectonic nature is the key to a better understanding of orogenic belts, which may apply to all the orogenic belts around the world. We also point out that several important issues regarding the detailed anatomy of the structures, compositions and tectonic nature of the Himalayan orogeny in future.XIAO WenJiao AO SongJian YANG Lei HAN ChunMing WAN Bo ZHANG Ji'En ZHANG ZhiYong LI Rui CHEN ZhenYu SONG ShuaiHua 2017Science China Earth Sciences2017,60,6:20
2Chemical characteristics of PM_(2.5) during haze episodes in the urban of Fuzhou,China显示文摘Atmospheric fine particles(PM_(2.5)) were collected in this study with middle volume samplers in Fuzhou,China,during both normal days and haze days in summer(September 2007) and winter(January 2008).The concentrations,distributions,and sources of polycyclic aromatic hydrocarbons(PAHs),organic carbon(OC),elemental carbon(EC),and water soluble inorganic ions(WSIIs) were determinated.The results showed that the concentrations of PM2.5,PAHs,OC,EC,and WSIIs were in the orders of haze > normal and winter > summer.The dominant PAHs of PM2.5 in Fuzhou were Fluo,Pyr,Chr,BbF,BkF,BaP,BghiP,and IcdP,which represented about 80.0%of the total PAHs during different sampling periods.The BaPeq concentrations of ∑PAHs were 0.78,0.99,1.22,and 2.43 ng/m3 in summer normal,summer haze,winter normal,and winter haze,respectively.Secondary pollutants(SO_4^(2-),NO_3^-,NH_4^+.and OC) were the major chemical compositions of PM2.5,accounting for 69.0%,55.1%,63.4%,and 64.9%of PM2.5 mass in summer normal,summer haze,winter normal,and winter haze,respectively.Correspondingly,secondary organic carbon(SOC) in Fuzhou accounted for 20.1%,48.6%,24.5%,and 50.5%of OC.The average values of nitrogen oxidation ratio(NOR) and sulfur oxidation ratio(SOR) were higher in haze days(0.08 and 0.27) than in normal days(0.05 and 0.22).Higher OC/EC ratios were also found in haze days(5.0) than in normal days(3.3).Correlation analysis demonstrated that visibility had positive correlations with wind speed,and negative correlations with relative humidity and major air pollutants.Overall,the enrichments of PM_(2.5),OC,EC,SO_4^(2-),and NO_3^- promoted haze formation.Furthermore,the diagnostic ratios of IcdP/(IcdP + BghiP),IcdP/BghiP,OC/EC,and NO_3^-/SO_4^(2-) indicated that vehicle exhaust and coal consumption were the main sources of pollutants in Fuzhou.Fuwang Zhang Lingling Xu Jinsheng Chen Xiaoqiu Chen Zhenchuan Niu Tong Lei Chunming Li Jinping Zhao 2013Particuology2013,11,3:19
3Influences of milling and grinding on machined surface roughness and fatigue behavior of GH4169 superalloy workpieces显示文摘Surface topography of superalloy GH4169 workpieces machined by milling and grinding is different significantly. Meanwhile, surface roughness, as one of the main indicators of machined surface integrity, has a great influence on the fatigue behavior of workpieces. Based on analyzing the formation mechanism and characteristics of surface roughness utilizing different machining processes and parameters, the machined surface roughness curve can be decoupled into two parts utilizing frequency spectrum analysis, which are kinematic surface roughness curve and stochastic surface roughness curve. The kinematic surface roughness curve is influenced by machining process,parameters, geometry of the cutting tool or wheel, the maximum height of which is expressed as R'_z.By subtracting the kinematic part from the measurement curve, the stochastic surface roughness curve and its maximum height R''_zcan be obtained, which is influenced by the defects of cutting tool edge or abrasive grains, built-up edges(BUE), cracks, high frequency vibration and so on. On the other hand, the results of decoupling analysis of surface roughness curves indicate that Raand Rz values of milling GH4169 are 2–5 times and 1–3 times as high as those of grinding, while R''_zvalue of milling is 13.85%–37.7% as high as that of grinding. According to the results of fatigue life tests of specimens machined by milling and grinding, it can be concluded that fatigue behavior of GH4169 decreases with the increase of R''_zmonotonically, even utilizing different machining processes.Xun LI Chunming GUAN Peng ZHAO 2018Chinese Journal of Aeronautics2018,31,6:16
4Accretionary processes and metallogenesis of the Central Asian Orogenic Belt:Advances and perspectives显示文摘As one of the largest Phanerozoic orogens in the world,the Central Asian Orogenic Belt(CAOB)is a natural laboratory for studies of continental dynamics and metallogenesis.This paper summarizes the research progresses of the accretionary processes and metallogenesis of the CAOB since the Peopled Republic of China was founded,and puts forward the prospect for future research.During the early period(1950s-1970s),several geological theories were applied to explain the geological evolution of Central Asia.In the early period of China's reform and opening-up,the plate tectonics theory was applied to explain the evolution of the northern Xinjiang and Xingmeng regions,and the opinion of subduction-collision between Siberian Kazakhstan and China-North Korea-Tarim plates was proposed.The idea of the Solonker-Yanbian suture zone was established.In the 1990s,the study of the CAOB entered a period of rapid development.One school of scholars including geologists from the former Soviet Union proposed a multi-block collision model for the assemblage of the CAOB.In contrast,another school of scholars,led by a Turkish geologist,Celal Sengor,proposed that the Altaids was formed through the growth and strike-slip duplicates of a single island arc,and pointed out that the Altaids is a special type of collisional orogen.During this period,Chinese geologists carried out a lot of pioneering researches on ophiolites and high-pressure metamorphic rocks in northern China,and confirmed the main suture zones accordingly.In 1999,the concept of'Central Asian metallogenic domain'was proposed,and it became one of the three major metallogenic domains in the world.Since the 21st century,given the importance for understanding continental accretion and metallogenic mechanism,the CAOB has become the international academic forefront.China has laid out a series of scientific research projects in Central Asia.A large number of important scientific research achievements have been spawned,including the tectonic attribution of micro-continents,timing and tectonic settings of ophiolites,magmatic arcs,identification and anatomy of accretionary wedges,regional metamorphism-deformation,(ultra)high-pressure metamorphism,ridge subduction plume-plate interaction archipelagic paleogeography and spatio-temporal framework of multiple accretionary orogeny,continental growth accretionary metallogenesis,structural superposition and transformation etc.These achievements have made important international influences.There still exist the following aspects that need further study:(1)Early evolution history and subduction initiation of the Paleo-Asian Ocean;(2)The accretionary mechanism of the extroversion Paleo-Asian Ocean;(3)The properties of the mantle of the Paleo-Asian Ocean and their spatiotemporal distribution;(4)The interaction between the Paleo-Asian Ocean and the Tethys Ocean;(5)Phanerozoic continental growth mechanism and its global comparison;(6)Accretionary metallogenic mechanism of the Central Asian metallogenic domain;and(7)Continental transformation mechanism.Wenjiao XIAO Dongfang SONG Brian FWINDLEY Jiliang LI Chunming HAN Bo WAN Ji'en ZHANG Songjian AO Zhiyong ZHANG 2020Science China Earth Sciences2020,63,3:16
5Drag models for simulating gas–solid flow in the turbulent fluidization of FCC particles显示文摘This paper examines the suitability of various drag models for predicting the hydrodynamics of the turbulent fluidization of FCC particles on the Fluent V6.2 platform.The drag models included those of Syamlal–O’Brien,Gidaspow,modified Syamlal–O’Brien,and McKeen.Comparison between experimental data and simulated results showed that the Syamlal–O’Brien,Gidaspow,and modified Syamlal–O’Brien drag models highly overestimated gas–solid momentum exchange and could not predict the formation of dense phase in the fluidized bed,while the McKeen drag model could not capture the dilute charac- teristics due to underestimation of drag force.The standard Gidaspow drag model was then modified by adopting the effective particle cluster diameter to account for particle clusters,which was,however, proved inapplicable for FCC particle turbulent fluidization.A four-zone drag model(dense phase,subdense phase,sub-dilute phase and dilute phase)was finally proposed to calculate the gas–solid exchange coefficient in the turbulent fluidization of FCC particles,and was validated by satisfactory agreement between prediction and experiment.Peng Li Xingying Lan Chunming Xu Gang Wang Chunxi Lu Jinsen Gao 2009Particuology2009,7,4:13
6Exposure to polycyclic aromatic hydrocarbons and risk for premature ovarian failure and reproductive hormones imbalance显示文摘Polycyclic aromatic hydrocarbons(PAHs)are a typical class of persistent organic pollutants that is ubiquitous worldwide.Previous animal studies suggested that PAHs had adverse effects on female reproduction.However,the human data regarding relationship of PAHs exposure with women reproductive health,such as ovarian dysfunction,are scarce.In this case-control study,the associations of serum levels of PAHs with the risk of premature ovarian failure(POF)and reproductive hormones in Chinese women were investigated,with recruiting 157 POF patients and 217 healthy women.The serum levels of 12 types of PAHs,as well as reproductive hormones,including follicle-stimulating hormone,luteinizing hormone and anti-mullerian hormone,were determined.In the logistic regression models,most individual PAH congeners showed significantly positive correlations with the risk of POF(p<0.05),except for fluorine and pyrene.Benzo(a)pyrene(BaP),as the most carcinogenic PAH congener,was observed to be significantly positively associated with the risk of POF.After adjustment for age,body mass index,educational levels and household income,per one-unit increase in the log-transformed BaP concentration was significantly correlated with 2.191-fold increased risk of POF(OR=2.191,95%CI:1.634-2.938,p<0.05).To the best of our knowledge,this is the first study to report an association between internal exposure levels of PAHs and the increased risk of POF in women.Xiaoqing Ye Wuye Pan Chunming Li Xiaochen Ma Shanshan Yin Jianhong Zhou Jing Liu 2020Journal of Environmental Sciences2020,32,5:10
7Secure Big Data Storage and Sharing Scheme for Cloud Tenants显示文摘The Cloud is increasingly being used to store and process big data for its tenants and classical security mechanisms using encryption are neither sufficiently efficient nor suited to the task of protecting big data in the Cloud.In this paper,we present an alternative approach which divides big data into sequenced parts and stores them among multiple Cloud storage service providers.Instead of protecting the big data itself,the proposed scheme protects the mapping of the various data elements to each provider using a trapdoor function.Analysis,comparison and simulation prove that the proposed scheme is efficient and secure for the big data of Cloud tenants.CHENG Hongbing RONG Chunming HWANG Kai WANG Weihong LI Yanyan 2015China Communications2015,12,6:10
8CROWN:A service grid middleware with trust management mechanism显示文摘Based on a proposed Web service-based grid architecture, a service grid middleware system called CROWN is designed in this paper. As the two kernel points of the middleware, the overlay-based distributed grid resource management mechanism is proposed, and the policy-based distributed access control mechanism with the capability of automatic negotiation of the access control policy and trust management and negotia- tion is also discussed in this paper. Experience of CROWN testbed deployment and ap- plication development shows that the middleware can support the typical scenarios such as computing-intensive applications, data-intensive applications and mass information processing applications.HUAI Jinpeng HU Chunming LI Jianxin SUN Hailong WO Tianyu 2006Science in China(Series F)2006,49,6:8
9Perspective of hydrogen energy and recent progress in electrocatalytic water splitting显示文摘As a secondary energy with great commercialization potential,hydrogen energy has been widely studied due to the high calorific value,clean combustion products and various reduction methods.At present,the blueprint of hydrogen energy economy in the world is gradually taking shape.Compared with the traditional high-energy consuming methane steam reforming hydrogen production method,the electrocatalytic water splitting hydrogen production stands out among other process of hydrogen production owning to the mild reaction conditions,high-purity hydrogen generation and sustainable production process.Basing on current technical economy situation,the highly electric power cost limits the further promotion of electrocatalytic water splitting hydrogen production process.Consequently,the rational design and development of low overpotential and high stability electrocatalytic water splitting catalysts are critical toward the realization of low-cost hydrogen production technology.In this review,we summarize the existing hydrogen production methods,elaborate the reaction mechanism of the electrocatalytic water splitting reaction under acidic and alkaline conditions and the recent progress of the respective catalysts for the two half-reactions.The structure-activity relationship of the catalyst was deep-going discussed,together with the prospects of electrocatalytic water splitting and the current challenges,aiming at provide insights for electrocatalytic water splitting catalyst development and its industrial applications.Yixuan Gong Jiasai Yao Ping Wang Zhenxing Li Hongjun Zhou Chunming Xu 2022Chinese Journal of Chemical Engineering2022,35,3:7
10Lipids of sulfate-reducing bacteria and sulfur-oxidizing bacteria found in the Dongsheng uranium deposit显示文摘U-bearing sandstones from the Dongsheng deposit in Ordos Basin contain abundant C15-C18 fatty acids. The fatty acids may have been derived from modern and ancient organisms including organisms from the intervals of U mineralization. A certain amount of i15:0, a15:0, a17:0 fatty acids coexist with small amounts of i17:1ω7c and 10me16:0, characteristic biomarkers of Desulfovibrio and Desulfobacter sp., respectively. This indicates the existence of sulfate-reducing bacteria (SRB) in the sandstones. The presence of sulfur-oxidizing bacteria (SOB), such as Beggiatoa and Thioploca, is indicated by significant amounts of 16:1ω7c and 18:1ω7c fatty acids. The existence of the SRB in the deposit, as inferred from the fatty acids, is consistent with results from fossilized microorganisms and isotopic compositions of ore-stage pyrite. This suggests that the environment may have been favorable for the SRB to grow since ore formation (9.8-22 Ma). The bacteria may have degraded hydrocarbons directly, or indirectly utilized hydrocarbons degraded by oxic microbes in the deposits. This process may have produced 12C-rich calcite and prominent baseline humps of unresolved complex mixtures (UCM), and 25-demethylated hopanes and tricyclic terpanes. The existence of sulfur-oxidizing bacteria and sulfate-reducing bacteria in the deposit may have resulted in bacterial sulfate reduction to sulfide, re-oxidization of the sulfide to sulfate and subsequent reduction of the sulfate to sulfide. This assertion is supported by ore-stage pyrite with δ34S values as low as-39.2‰, and the lightest sulfate (about 11‰) measured during the Phanerozoic, a difference of more than 46‰.JIANG Lei CAI ChunFang ZHANG YongDong MAO ShengYi SUN YongGet LI KaiKai XIANG Lei ZHANG ChunMing 2012Chinese Science Bulletin2012,57,11:6
11Geochemical characteristics and genetic types of crude oils from the Tertiary system in the southern part of western Qaidam Basin,Northwest China显示文摘Crude oil samples taken from the southern part of western Qaidam Basin were analyzed with GC/MS in order to understand the geochemical characteristics of crude oils.The results reveal that most crude oils are characterized by high abundance of gammacerane and C35 homohopane,which are the representative characteristics of saline lacustrine crude oils.Based on the variation of the ratios of gammacerane/C30 hopane(G/H) and C35 homoho-pane/C34 homohopane(C35/C34H),two crude oil groups,A and B,are identified.Group-A crude oils mainly occurr in the north of the study area,with higher ratios of G/H(>0.8) and C35/C34H(>1.2),whereas group-B crude oils,selected from the south of the study area,show lower ratios of G/H(<0.8) and C35/C34H(<1.0).In addition,group-A crude oils are distinguished into three subgroups in accordance with their different ratios of G/H and C35/C34H and different distribution characteristics of n-alkanes,isoprenoids and steranes.These may be helpful for understanding the distribution characteristics of crude oils in the southern part of western Qaidam Basin and providing clues to the forthcoming exploration of crude oils and gas.LI Hongbo ZHANG Min ZHANG Chunming PENG Dehua 2008Chinese Journal Of Geochemistry2008,27,3:5
12The effect of slight to minor biodegradation on C_6 to C_7 light hydrocarbons in crude oils: a case study from Dawanqi Oilfield in the Tarim Basin,NW China显示文摘Light hydrocarbons(LHs) are one of the main petroleum fractions in crude oils, and carry much information regarding the genetic origin and alteration of crude oils. But secondary alterations—especially biodegradation—have a significant effect on the composition of LHs in crude oils. Because most of the LHs affected in oils underwent only slight biodegradation(rank 1 on the biodegradation scale), the variation of LHs can be used to describe more the refined features of biodegradation. Here,23 crude oils from the Dawanqi Oilfield in the Tarim Basin, NW China, eleven of which have been biodegraded to different extents, were analyzed in order to investigate the effect of slight to minor biodegradation on C_6–C_7 LHs.The study results showed that biodegradation resulted in the prior depletion of straight-chained alkanes, followed by branched alkanes. In slight and minor biodegraded oils,such biodegradation scale could not sufficiently affect C_6–C_7cycloalkanes. For branched C_6–C_7 alkanes, generally,monomethylalkanes are biodegraded earlier than dimethylalkanes and trimethylalkanes, which indicates that branched alkanes are more resistant to biodegradation, with the increase of substituted methyl groups on parent rings.The degree of alkylation is one of the primary controlling factors on the biodegradation of C_6–C_7 LHs. There is a particular case: although 2,2,3-trimethylbutane has a relative higher alkylation degree, 2,2-dimethylpentane is more resistant to biodegradation than 2,2,3-trimethylbutane. 2,2-Dimethylpentane is the most resistant to biodegradation in branched C_6–C_7 alkanes. Furthermore, the 2-methylpentane/3-methylpentane and 2-methylhexane/3-methylhexane ratios decreased steadily with increasing biodegradation,which implies that isomers of bilateral methyl groups are more prone to bacterial attack relative to mid-chain isomers. The position of the alkyls on the carbon skeleton is also one of the critical factors controlling the rate of biodegradation. With increasing biodegradation, Mango's LH parameters K1 values decrease and K2 values increase,the values of n-heptane and isoheptane decrease, and the indices of methylcyclohexane and cyclohexane increase.LH parameters should be applied cautiously for the biodegraded oils. Because biodegraded samples belong to slight or minor biodegraded oils, the values of n-heptane and isoheptane from Dawanqi Oilfield can better reflect and determine the ‘‘Biodegraded'' zone. When the heptane value is 0–21 and the isoheptane value is 0–2.6, the crude oil in Dawanqi Oilfield is defined as the ‘‘Biodegraded'' zone.Lu Yang Chunming Zhang Meijun Li Jing Zhao Xuening Qi Jinxiu Du 2016Acta Geochimica2016,35,2:5
13Big graph search: challenges and techniques显示文摘Shuai MA Jia LI Chunming HU Xuelian LIN Jinpeng HUAI 2016Frontiers of Computer Science2016,10,3:5
14Bis(trifluoromethylsulfonyl)phenylamines as Internal Donors for Ziegler-Natta Polymerization Catalysts显示文摘几二度(trifluoromethylsulfonyl ) phenylamines 被综合了并且为丙烯聚合为异构的 Ziegler-Natta 催化剂的准备用作内部施主。这些新催化剂是高度活跃的并且在有为丙烯的聚合的一个外部施主的联合的 stereospecific。这些催化剂的活动被苯基取代者的电子能力戏剧性地在 sulfonyl phenylamines 上影响。因此,催化剂的表演能被调整 sulfonyl phenylamines 的苯基取代者的电子性质修改。Li Huashu Yi Jianjun Cui Chunming 2008China Petroleum Processing & Petrochemical Technology2008,10,3:5
15Green hydrogen:A promising way to the carbon-free society显示文摘With increasing importance attached by the international community to global climate change and the pressing energy revolution,hydrogen energy,as a clean,efficient energy carrier,can serve as an important support for the establishment of a sustainable society.The United States and countries in Europe have already formulated relevant policies and plans for the use and development of hydrogen energy.While in China,aided by the“30·60”goal,the development of the hydrogen energy,production,transmission,and storage industries is steadily advancing.This article comprehensively considers the new energy revolution and the relevant plans of various countries,focuses on the principles,development status and research hot spots,and summarizes the different green hydrogen production technologies and paths.In addition,based on its assessment of current difficulties and bottlenecks in the production of green hydrogen and the overall global hydrogen energy development status,this article discusses the development of green hydrogen technologies.Ying Zhou Ruiying Li Zexuan Lv Jian Liu Hongjun Zhou Chunming Xu 2022Chinese Journal of Chemical Engineering2022,35,3:5
16Deployment of Sensors in WSN: An Efficient Approach Based on Dynamic Programming显示文摘Efficient sensor node deployment is extremely important in wireless sensor networks. It earns great practical meanings through using fewer sensor nodes as far as possible to satisfy different requirements such as the requirement on coverage and overcoming the potential sensor node failures and the adverse influence from the environment. We propose an efficient approach for the deployment of sensor nodes in wireless networks, termed as EDSNDA, which is excellent in taking both the requirements of sensor coverage and network connectivity into consideration when minimizing the number of necessary sensor nodes to the best of its ability. We proposed a new coverage model of sensor node. Based on the sensor coverage model, we establish four dynamic programming models in four different practical situations, respectively. The algorithms are then proposed which are used for solving the corresponding dynamic programming models. The validity of the method is justified by simulation studies in which the method is compared with the current representative methods. The simulation results show that our method performs better than the other ones with fewer sensor nodes, better coverage and network connectivity result in the same circumstance.LI Yongyan GAO Wen WU Chunming WANG Yansong 2015Chinese Journal of Electronics2015,24,1:4
17Global perspectives and future research directions for the phytoremediation of heavy metal-contaminated soil:A knowledge mapping analysis from 2001 to 2020显示文摘In total,9,552 documents were extracted from the Web of Science Core Collection and subjected to knowledge mapping and visualization analysis for the field of phytoremediation of HM-contaminated soil(PHMCS)with CiteSpace 5.7 R3 software.The results showed that(1)the number of publications increased linearly over the studied period.The top 10 countries/regions,institutions and authors contributing to this field were exhibited.(2)Keyword co-occurrence cluster analysis revealed a total of 8 clusters,including“Bioremediation,”“Arsenic,”“Biochar,”“Oxidative stress,”“Hyperaccumulation,”“EDTA,”“Arbuscular mycorrhizal fungi,”and“Environmental pollution”clusters(3)In total,334 keyword bursts were obtained,and the 25 strongest,longest duration,and newest keyboard bursts were analyzed in depth.The strongest keyword burst test showed that the hottest keywords could be divided into 7 groups,i.e.,“Plant bioremediation materials,”“HM types,”“Chelating amendments,”“Other improved strategies,”“Bioremediation characteristics,”“Risk assessment,”and“Other.”Almost half of the newest topics had emerged in the past 3 years,including“biochar,”“drought,”“health risk assessment,”“electrokinetic remediation,”“nanoparticle,”and“intercropping.”(4)In total,9 knowledge base clusters were obtained in this study.The studies of Ali et al.(2013),Blaylock et al.(1997),Huang et al.(1997),van der Ent et al.(2013),Salt et al.(1995),and Salt(1998),which had both high frequencies and the strongest burst scores,have had the most profound effects on PHMCS research.Finally,future research directions were proposed.Kehui Liu Xiaojin Guan Chunming Li Keyi Zhao Xiaohua Yang Rongxin Fu Yi Li Fangming Yu 2022Frontiers of Environmental Science & Engineering2022,16,6:4
18DNA Methylation Affects Gene Alternative Splicing in Plants: An Example from Rice显示文摘Wang, Xutong Hu, Lanjuan Wang, Xiaofei Li, Ning Xu, Chunming Gong, Lei Liu, Bao 2016Molecular Plant2016,9,2:3
19Two-Order Approximate and Large Stepsize Numerical Direction Based on the Quadratic Hypothesis and Fitting Method显示文摘Many effective optimization algorithms require partial derivatives of objective functions, while some optimization problems' objective functions have no derivatives. According to former research studies, some search directions are obtained using the quadratic hypothesis of objective functions. Based on derivatives, quadratic function assumptions, and directional derivatives, the computational formulas of numerical first-order partial derivatives, second-order partial derivatives, and numerical second-order mixed partial derivatives were constructed. Based on the coordinate transformation relation, a set of orthogonal vectors in the fixed coordinate system was established according to the optimization direction. A numerical algorithm was proposed, taking the second order approximation direction as an example. A large stepsize numerical algorithm based on coordinate transformation was proposed. Several algorithms were validated by an unconstrained optimization of the two-dimensional Rosenbrock objective function. The numerical second order approximation direction with the numerical mixed partial derivatives showed good results. Its calculated amount is 0.2843% of that of without second-order mixed partial derivative. In the process of rotating the local coordinate system 360°, because the objective function is more complex than the quadratic function, if the numerical direction derivative is used instead of the analytic partial derivative, the optimization direction varies with a range of 103.05°. Because theoretical error is in the numerical negative gradient direction, the calculation with the coordinate transformation is 94.71% less than the calculation without coordinate transformation. If there is no theoretical error in the numerical negative gradient direction or in the large-stepsize numerical optimization algorithm based on the coordinate transformation, the sawtooth phenomenon occurs. When each numerical mixed partial derivative takes more than one point, the optimization results cannot be improved. The numerical direction based on the quadratic hypothesis only requires the objective function to be obtained, but does not require derivability and does not take into account truncation error and rounding error. Thus, the application scopes of many optimization methods are extended.Xiaoli Yin Chunming Li Yuan Zhang 2020IEEE/CAA Journal of Automatica Sinica2020,7,3:3
20Force/Moment Isotropy of 8/4-4 Parallel Six-Axis Force Sensor Based on Performance Atlases显示文摘A six-axis force sensor with parallel 8/4-4 structure is introduced and its measurement principle is analyzed.Based on condition numbers of Jacobian matrix spectral norm of the sensor,the relationship between the force and moment isotropy and some structural parameters is deduced.Orthogonal test methods are used to determine the degree of primary and secondary factors that have significant effect on sensor characteristics.Furthermore,the relationship between each performance index and the structural parameters of the sensor is analyzed by the method of the atlas,which lays a foundation for structural optimization design of the force sensor.Song Weishan Li Chenggang Wang Chunming Song Yong Wu Zefeng Rajnathsing Hemant 2018Transactions of Nanjing University of Aeronautics and Astronautics2018,35,6:3
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