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Partial stability analysis of nonlinear time-varying impulsive systems
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作者 Boulbaba Ghanmi 《生物数学学报:英文版》 2019年第6期73-98,共26页
This paper investigates the stability analysis with respect to part of the variables of nonlinear time-varying systems with impulse effect.The approach presented is based on the specially introduced piecewise continuo... This paper investigates the stability analysis with respect to part of the variables of nonlinear time-varying systems with impulse effect.The approach presented is based on the specially introduced piecewise continuous Lyapunov functions.The Lyapunov stability theorems with respect to part of the variables are generalized in the sense that the time derivatives of the Lyapunov functions are allowed to be indefinite.With the help of the notion of stable functions,asymptotic partial stability,exponential partial stability,input-to-state partial stability(ISPS)and integral input-to-state partial stability(iISPS)are considered.Three numerical examples are provided to illustrate the effectiveness of the proposed theoretical results. 展开更多
关键词 Nonlinear impulsive systems partial stability piecewise continuous scalar functions indefinite Lyapunov function input-to-state partial stability(ISPS) integral input-to-state partial stability(iISPS).
Asymptotic and Partial Asymptotic Hankel Operators on H~2(D~n)
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作者 Anuradha GUPTA Bhawna GUPTA 《数学学报:英文版》 SCIE CSCD 2019年第11期1729-1740,共12页
In this paper,we generalize the concept of asymptotic Hankel operators on H2(D)to the Hardy space H2(Dn)(over polydisk)in terms of asymptotic Hankel and partial asymptotic Hankel operators and investigate some propert... In this paper,we generalize the concept of asymptotic Hankel operators on H2(D)to the Hardy space H2(Dn)(over polydisk)in terms of asymptotic Hankel and partial asymptotic Hankel operators and investigate some properties in case of its weak and strong convergence.Meanwhile,we introduce ith-partial Hankel operators on H2(Dn)and obtain a characterization of its compactness for n>1.Our main results include the containment of Toeplitz algebra in the collection of all strong partial asymptotic Hankel operators on H2(Dn).It is also shown that a Toeplitz operator with symbolφis asymptotic Hankel if and only if φ is holomorphic function in L∞(Tn). 展开更多
关键词 HANKEL OPERATOR ASYMPTOTIC HANKEL OPERATOR PARTIAL ASYMPTOTIC HANKEL OPERATOR i(th)-partial HANKEL OPERATOR i(th)-partial big HANKEL OPERATOR
偏缠绕结构的上同调(英文) 预览
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作者 贾玲 《数学季刊:英文版》 2019年第1期66-74,共9页
In this paper we mainly reveal the rich cohomology theories for partial entwining structures.
关键词 PARTIAL entwining STRUCTURE PARTIAL entwined MODULE COHOMOLOGY
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Forward and Backward Mean-Field Stochastic Partial Differential Equation and Optimal Control
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作者 Maoning TANG Qingxin MENG Meijiao WANG 《数学年刊:B辑英文版》 SCIE CSCD 2019年第4期515-540,共26页
This paper is mainly concerned with the solutions to both forward and backward mean-field stochastic partial differential equation and the corresponding optimal control problem for mean-field stochastic partial differ... This paper is mainly concerned with the solutions to both forward and backward mean-field stochastic partial differential equation and the corresponding optimal control problem for mean-field stochastic partial differential equation. The authors first prove the continuous dependence theorems of forward and backward mean-field stochastic partial differential equations and show the existence and uniqueness of solutions to them. Then they establish necessary and sufficient optimality conditions of the control problem in the form of Pontryagin’s maximum principles. To illustrate the theoretical results, the authors apply stochastic maximum principles to study the infinite-dimensional linear-quadratic control problem of mean-field type. Further, an application to a Cauchy problem for a controlled stochastic linear PDE of mean-field type is studied. 展开更多
关键词 MEAN-FIELD STOCHASTIC PARTIAL DIFFERENTIAL EQUATION BACKWARD STOCHASTIC PARTIAL DIFFERENTIAL EQUATION Optimal control Maximum principle Adjoint EQUATION
Partial Differential Equations and Continuum Mechanics:a Collection of Papers Dedicated to Professor Philippe G. Ciarlet on the Occasion of His 80th Birthday
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作者 Cristinel MARDARE Tong YANG 《应用数学学报:英文版》 SCIE CSCD 2019年第1期1-2,共2页
Preface This Special Issue in'Acta Mathematicae Applicatae Sinica(English Series)'gathers peer reviewed papers dedicated to Professor Philippe G.Ciarlet on the occasion of his eightieth birthday.Written by fri... Preface This Special Issue in'Acta Mathematicae Applicatae Sinica(English Series)'gathers peer reviewed papers dedicated to Professor Philippe G.Ciarlet on the occasion of his eightieth birthday.Written by friends and colleagues from France and Hong Kong/China,they stand as a testimony of their admiration for an exceptional human being and mathematician. 展开更多
关键词 Partial Differential Equations CONTINUUM Mechanics
A Review on Stochastic Multi-symplectic Methods for Stochastic Maxwell Equations 预览
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作者 Liying Zhang Chuchu Chen +1 位作者 Jialin Hong Lihai Ji 《应用数学与计算数学学报(英文)》 2019年第3期467-501,共35页
Stochastic multi-symplectic methods are a class of numerical methods preserving the discrete stochastic multi-symplectic conservation law. These methods have the remarkable superiority to conventional numerical method... Stochastic multi-symplectic methods are a class of numerical methods preserving the discrete stochastic multi-symplectic conservation law. These methods have the remarkable superiority to conventional numerical methods when applied to stochastic Hamiltonian partial differential equations (PDEs), such as long-time behavior, geometric structure preserving, and physical properties preserving. Stochastic Maxwell equations driven by either additive noise or multiplicative noise are a system of stochastic Hamiltonian PDEs intrinsically, which play an important role in fields such as stochastic electromagnetism and statistical radiophysics. Thereby, the construction and the analysis of various numerical methods for stochastic Maxwell equations which inherit the stochastic multi-symplecticity, the evolution laws of energy and divergence of the original system are an important and promising subject. The first stochastic multi-symplectic method is designed and analyzed to stochastic Maxwell equations by Hong et al.(A stochastic multi-symplectic scheme for stochastic Maxwell equations with additive noise. J. Comput. Phys. 268:255-268, 2014). Subsequently, there have been developed various stochastic multi-symplectic methods to solve stochastic Maxwell equations. In this paper, we make a review on these stochastic multi-symplectic methods for solving stochastic Maxwell equations driven by a stochastic process. Meanwhile, the theoretical results of well-posedness and conservation laws of the stochastic Maxwell equations are included. 展开更多
关键词 STOCHASTIC MULTI-SYMPLECTIC METHODS STOCHASTIC HAMILTONIAN partial differential EQUATIONS STOCHASTIC Maxwell EQUATIONS Structure-preserving METHODS
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Rapid Acclimation of Methanogenic Granular Sludge into Autotrophic Partial Denitrification Granules 预览
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作者 Liu Chunshuang Li Xuechen +4 位作者 Zhang Xiaofei Bai Xue Guo Yadong Wang Yongxing Zhao Chaocheng 《中国炼油与石油化工:英文版》 SCIE CAS 2019年第3期68-73,共6页
Rapid formation of autotrophic partial denitrification(APD)granules is of practical interest to start up an expanded granular sludge bed reactor for wastewater treatment.This study demonstrates that methanogenic granu... Rapid formation of autotrophic partial denitrification(APD)granules is of practical interest to start up an expanded granular sludge bed reactor for wastewater treatment.This study demonstrates that methanogenic granules can be easily acclimated into autotrophic partial denitrification granules in one day,with the ability to remove 82%of 2.7 kg-S/(m^3·d)sulfide into S^0 and to convert 97%of 0.9 kg-N/(m^3·d)nitrate into nitrite,which can provide a promising feedstock for anaerobic ammonia oxidation process.Arcobacter sp.is essential for S^0 accumulation.Under high loadings,the abundance of Arcobacter sp.decreased,while on the contrary the abundance of unclassified_p_Firmicutes increased,leading to the deterioration of autotrophic partial denitrification performance.The granules performance could be recovered by adopting the strategies of properly reducing the influent loadings. 展开更多
关键词 METHANOGENIC GRANULES NITRITE ACCUMULATION AUTOTROPHIC partial denitri fication sul fide
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On-node lattices construction using partial Gauss–Hermite quadrature for the lattice Boltzmann method
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作者 叶欢锋 干则成 +1 位作者 匡波 杨燕华 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第5期175-180,共6页
A concise theoretical framework,the partial Gauss–Hermite quadrature (pGHQ),is established to construct on-node lattices of the lattice Boltzmann (LB) method under a Cartesian coordinate system.Compared with the exis... A concise theoretical framework,the partial Gauss–Hermite quadrature (pGHQ),is established to construct on-node lattices of the lattice Boltzmann (LB) method under a Cartesian coordinate system.Compared with the existing approaches,the pGHQ scheme has the following advantages: extremely concise algorithm,unifies the constructing procedure for symmetric and asymmetric on-node lattices,and covers a full-range quadrature degree of a given discrete velocity set.We employ the pGHQ scheme to search the local optimal and asymmetric lattices for {n = 3,4,5,6,7} moment degree equilibrium distribution discretization on the range [-10,10].The search reveals a surprising abundance of available lattices.Through a brief analysis,the discrete velocity set shows a significant influence on the positivity of equilibrium distributions,which is considered as one of the major impacts of the numerical stability of the LB method.Hence,the results of the pGHQ scheme lay a foundation for further investigations to improve the numerical stability of the LB method by modifying the discrete velocity set.It is also worth noting that pGHQ can be extended into the entropic LB model,even though it was proposed for the Hermite polynomial expansion LB theory. 展开更多
关键词 equilibrium distribution DISCRETIZATION PARTIAL Gauss–Hermite QUADRATURE
Clinical outcomes and safety of high-resolution manometry guided superficial partial circular muscle myotomy in per-oral endoscopic myotomy for Jackhammer esophagus:Two cases report 预览
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作者 Youn I Choi Kyoung Oh Kim +3 位作者 Dong Kyun Park Jun-Won Chung Yoon Jae Kim Kwang An Kwon 《世界临床病例杂志》 2019年第16期2322-2329,共8页
BACKGROUND Jack hammer esophagus is a relatively rare disease and to date,there is no dramatic treatment option.Recently,conventional per-oral endoscopic myotomy (POEM) have expanded their area into Jackhammer esophag... BACKGROUND Jack hammer esophagus is a relatively rare disease and to date,there is no dramatic treatment option.Recently,conventional per-oral endoscopic myotomy (POEM) have expanded their area into Jackhammer esophagus.However,several complications such as post procedure motility disorders (e.g.,passage disturbance) are issues after POEM.To overcome these issues,we here introduced high-resolution manometry (HRM)-guided superficial partial circular muscle myotomy,which involves cutting only the superficial layer of the esophageal circular muscle.CASE SUMMARY We report two cases of patients with Jackhammer esophagus who were treated with HRM-guided extremely superficial partial circular muscle myotomy during POEM.Case 1 was a 53-year-old female with medication-refractory odynophagia and case 2 was a 47-year-old man who presented with chest pain.They were diagnosed with Jackhammer esophagus using HRM,and the hypercontractile segments of the esophagus were identified.HRM-guided extremely superficial partial circular muscle myotomy was performed while preserving the lower esophageal sphincter.Therefore,the circular and longitudinal muscle layers are preserved but hypercontractile movements are reduced,even after POEM.Patients’ clinical symptoms dramatically improved right after POEM,and 6-mo follow-up HRM revealed completely resolved status.During a 1-year follow-up period,patients were still in good health and remained symptom free.CONCLUSION HRM-guided superficial partial circular muscle myotomy may be a promising alternative to conventional POEM for treating Jackhammer esophagus with improved efficacy. 展开更多
关键词 Jackhammer ESOPHAGUS Hypercontractile PARTIAL CIRCULAR MUSCLE MYOTOMY Case REPORT
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Physiological and biochemical appraisal for mulching and partial rhizosphere drying of cotton 预览
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作者 Rashid IQBAL Muhammad A S RAZA +5 位作者 Muhammad F SALEEM Imran H KHAN Salman AHMAD Muhammad S ZAHEER Muhammad U ASLAM Imran HAIDER 《干旱区科学:英文版》 SCIE CSCD 2019年第5期785-794,共10页
Water is the main factor for the healthy life of plant.One of the main negative effects of climate change is the increasing scarcity of water that is lethal for plant.Globally,for water deficit regions(arid and semi-a... Water is the main factor for the healthy life of plant.One of the main negative effects of climate change is the increasing scarcity of water that is lethal for plant.Globally,for water deficit regions(arid and semi-arid),drought is the main factor responsible for low production of agriculture,especially for cotton.Great efforts have been and are being made to find alternatives to water saving practices.This study aimed to examine the effects of partial rhizosphere drying(PRD,half of the root system irrigated at one event,and the other half irrigated in the next event,and so on)with and/or without various mulching treatments on physiological and biochemical traits of cotton.To explore this objective,we laid out experiments in completely randomized design with factorial arrangement in the Islamia University of Bahawalpur,Pakistan in 2016.Two factors included were four mulching treatments(M0,no mulching;M1,black plastic mulching;M2,wheat straw mulching;and M3,cotton sticks mulching)and two irrigation levels(I0,control(full irrigation);and I1,PRD).Fisher's analysis of variance among means of treatments was compared using least significant difference test at 5% probability level.Results revealed that the maximum plant height,leaf area,leaf gas exchange(photosynthetic rate and stomata conductance),chlorophyll,proline and total sugar contents,and enzyme activities were higher under M2 than under other three mulching treatments.As for irrigation levels,higher values of plant height,photosynthesis and water related parameters(leaf water potential,leaf osmotic potential,leaf turgor potential,etc.)were recorded.Contents of total sugar and proline and activities of antioxidant enzymes were significantly higher in PRD-treated plants than in control plants.It was concluded that combined application of PRD and mulching was more effective than the rest of the treatments used in the experiment.Similar study can be conducted in the field by applying irrigation water in alternate rows in semi-arid regions. 展开更多
关键词 antioxidant enzymes MULCHING partial rhizosphere drying photosynthetic rate stomatal conductance
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On a biseparability criterion of bipartite qudit state
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作者 B Benzimoun M Daoud 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第8期42-49,共8页
In this paper,we propose a new approach to tackle the separability problem for bipartite qudit mixed-states.This is based on the Majorana representation which allows to represent a N-spinors(qudit)as a symmetric state... In this paper,we propose a new approach to tackle the separability problem for bipartite qudit mixed-states.This is based on the Majorana representation which allows to represent a N-spinors(qudit)as a symmetric state of N spin-1/2.We also discuss how we can exploit such representation and the notion of the biseparability of multipartite qubit states in the sense to establish new criteria of the separability problem based on the PPT and concurrence. 展开更多
关键词 SEPARABILITY BIPARTITE QUBIT STATE partial SEPARABILITY MAJORANA representation
Crystal structure and hydrogen storage properties of(La,Ce)Ni5-xMx(M=Al,Fe,or Co)alloys 预览
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作者 Wan-liang Mi Zhao-sen Liu +2 位作者 Toru Kimura Atsunori Kamegawa Hai-liang Wang 《矿物冶金与材料学报:英文版》 SCIE EI CAS CSCD 2019年第1期108-113,共6页
The effects of partial substitution of La by Ce and Ni by Al,Fe,or Co in LaNi5-based alloys on hydrogen storage performance were systematically studied.All samples were prepared using vacuum arc melting in an argon at... The effects of partial substitution of La by Ce and Ni by Al,Fe,or Co in LaNi5-based alloys on hydrogen storage performance were systematically studied.All samples were prepared using vacuum arc melting in an argon atmosphere.The results showed that for La-Ni5-xMx(M=Al,Fe,or Co)alloys,the lattice constants and unit cell volumes increased with an increasing amount of Al and Fe.On the other hand,these parameters decreased upon partial substitution of La by Ce.In addition,the lattice constant remained almost constant in the La0.6Ce0.4Ni5–xCox alloys regardless of the value of x(x=0.3,0.6,or 0.9),as Ce might enhance the homogeneity of the CaCu5-type phase in Co-containing alloys.The hydrogen storage properties of the alloys were investigated using pressure,composition,and temperature isotherms.The experimental results showed that the plateau pressure decreased with an increasing content of Al,Fe,or Co,but it increased with Ce addition.Furthermore,the plateau pressures of all Co-containing alloys were almost identical upon substitution with Ce.Finally,the enthalpy(ΔH)and entropy(ΔS)values for all alloys were calculated using van’t Hoff plots.The relationship between the lattice parameters and enthalpy changes for hydrogenation will be discussed. 展开更多
关键词 metal HYDRIDE LANI5 hydrogen storage ALLOYS partial SUBSTITUTION P-C-T CURVES thermodynamics
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Enhanced Autonomous Exploration and Mapping of an Unknown Environment with the Fusion of Dual RGB-D Sensors 预览
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作者 Ningbo Yu Shirong Wang 《工程(英文)》 2019年第1期164-172,共9页
The autonomous exploration and mapping of an unknown environment is useful in a wide range of applications and thus holds great significance. Existing methods mostly use range sensors to generate twodimensional (2D) g... The autonomous exploration and mapping of an unknown environment is useful in a wide range of applications and thus holds great significance. Existing methods mostly use range sensors to generate twodimensional (2D) grid maps. Red/green/blue-depth (RGB-D) sensors provide both color and depth information on the environment, thereby enabling the generation of a three-dimensional (3D) point cloud map that is intuitive for human perception. In this paper, we present a systematic approach with dual RGB-D sensors to achieve the autonomous exploration and mapping of an unknown indoor environment. With the synchronized and processed RGB-D data, location points were generated and a 3D point cloud map and 2D grid map were incrementally built. Next, the exploration was modeled as a partially observable Markov decision process. Partial map simulation and global frontier search methods were combined for autonomous exploration, and dynamic action constraints were utilized in motion control. In this way, the local optimum can be avoided and the exploration efficacy can be ensured. Experiments with single connected and multi-branched regions demonstrated the high robustness, efficiency, and superiority of the developed system and methods. 展开更多
关键词 AUTONOMOUS EXPLORATION Red/green/blue-depth Sensor fusion Point cloud Partial map simulation Global FRONTIER search
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Factors affecting recurrence after surgical treatment in cases with ocular surface squamous neoplasia
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作者 Ibadulla Mirzayev Ahmet Kaan Gündüz +2 位作者 Funda Seher?zalp Ate? G?k?en?zcan Mehmed U?ur I??k 《国际眼科杂志:英文版》 SCIE CAS 2019年第9期1426-1431,共6页
AIM: To evaluate the risk factors leading to recurrence in patients with ocular surface squamous neoplasia(OSSN)METHODS: The records of 112 patients with OSSN who underwent treatment and follow-up between February 199... AIM: To evaluate the risk factors leading to recurrence in patients with ocular surface squamous neoplasia(OSSN)METHODS: The records of 112 patients with OSSN who underwent treatment and follow-up between February 1999 and August 2018 were reviewed retrospectively.RESULTS: Totally 67 patients(59.8%) were male and 45 patients(40.2%) were female. The mean age at presentation was 63.7 y(range 22-87 y). Partial lamellar scleroconjunctivectomy(PLSC) was performed in 105(93.7%) cases and enucleation was performed in 7(6.3%) cases due to bulbus invasion as the first step treatment. Treatments used in addition to PLSC included cryotherapy in 78 eyes(74.3%), alcohol epitheliectomy in 57 eyes(54.3%) for presence of corneal involvement, and amniotic membrane transplantation in 17 eyes(16.2%) for ocular surface reconstruction. Topical mitomycin C was used in 10 patients(9.5%) and strontium-90(Str-90) treatment in 4(3.8%) patients because surgical margins were tumor positive at the histopathological examination. Postoperative histopathologic diagnoses were squamous cell carcinoma(52 cases), carcinoma in situ(44 cases), moderate conjunctival intraepithelial neoplasia(11 cases), and mild conjunctiva intraepithelial neoplasia(5 cases). At a mean follow-up of 20.1 mo, tumor recurrence was observed in 21(18.8%) cases. The rate of recurrence was found to be lower in cases that underwent supplemental cryotherapy compared to those that did not(P<0.001). There was no metastasis in any case. CONCLUSION: In our series, the recurrence rate is 18.8% and overall globe salvage rate is 90.2% for OSSN at relatively short-term follow-up. 展开更多
关键词 alcohol epitheliectomy CRYOTHERAPY MITOMYCIN C OCULAR surface squamous NEOPLASIA partial LAMELLAR scleroconjunctivectomy STRONTIUM-90
Re-folded structure of syn-orogenic granitoids(Padrón dome,NW Iberia):Assessing rheological evolution of cooling continental crust in a collisional setting 预览
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作者 Rubén Díez Fernández Francisco J.Rubio Pascual Luis Miguel Martín Parra 《地学前缘:英文版》 CAS CSCD 2019年第2期651-669,共19页
This contribution discusses about the rheological,kinematic and dynamic frameworks necessary to produce recumbent and upright folds from syn-orogenic granitic massifs that were formed during an early stage of magma ge... This contribution discusses about the rheological,kinematic and dynamic frameworks necessary to produce recumbent and upright folds from syn-orogenic granitic massifs that were formed during an early stage of magma genesis related to the onset of a migmatitic dome.Syn-kinematic granitoids occurring within the high-grade infrastructure of the Padrón migmatitic dome(NW Iberia)are deformed into largescale recumbent folds(D2)that are later affected by upright folds(D3).Petrostructural analysis of a selected area of this dome reveals that after a period of crustal thickening(D1),NNW-directed extensional flowgave way to recumbent folds and penetrative axial plane foliation(S2).Superimposed subhorizontal compression resulted in upright folds(D3).A closer view into the dynamics of the dome allows exploring the factors that may condition the nucleation of folds with contrasting geometries during progressive deformation of molten continental crust.The formation of folds affecting syn-kinematic granitoids suggests a cooling metamorphic path in migmatitic domes.Active and passive folding mechanisms require a crystallizing(cooling)magma to nucleate folds.A more competent metamorphic host inhibits fold nucleation from much less competent magmas.As it crystallizes,magma becomes more rigid(competent),and approaches viscosity values of its host.Passive folding is favored when no significant competence contrast exists between magma and host,so this folding mechanism is more likely shortly after magma genesis and emplacement.In such conditions,and under dominant subhorizontal flow accompanied by flattening(D2),passive folding would produce isoclinal recumbent geometries.Further magma cooling introduces a shift into the rheological behavior of partially molten crust.Thereon,crystallizing magma bodies would represent significant competence contrasts relative to their host.At this point,buckling is a more likely folding mechanism,and more regular,buckle folds re-fold previous structures after significant cooling.The geometry of resul 展开更多
关键词 Recumbent FOLDS Migmatitic DOMES Partial melting Crustal-derived GRANITOIDS OROGENIC collapse VARISCAN orogen
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Geochemical characterization of Granitoids in Katchuan Irruan area:further evidence for peraluminous and shoshonitic compositions and post-collisional setting of granitic rocks in the Precambrian Basement Complex of Nigeria
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作者 Chinedu U.Ibe Smart C.Obiora 《中国地球化学学报:英文版》 CSCD 2019年第5期734-752,共19页
Petrographic studies on Granitoids from Katchuan Irruan and adjoining areas,southeastern Nigeria,has shown that they are garnetiferous biotite granite,aplitic granite,porphyritic hornblende biotite granite,porphyritic... Petrographic studies on Granitoids from Katchuan Irruan and adjoining areas,southeastern Nigeria,has shown that they are garnetiferous biotite granite,aplitic granite,porphyritic hornblende biotite granite,porphyritic muscovite biotite granite,weakly foliated leucogranodiorite and simple pegmatite.They are closely associated with the Precambrian Basement Complex rocks which they intruded.Modal analysis shows that the rocks consist of quartz(10%-25%),oligoclase(10%-30%),K-feldspar(15%-35%),biotite(3%-25%),with occasional garnet,hornblende,muscovite,and accessory chlorite,haematite and magnetite.Geochemical data indicates that the rocks are generally shoshonitic,alkali-calcic to calcic,ferroan and peraluminous.They are enriched in large ion lithophile elements as well as high field strength elements(Hf,Ta,Yb,Sm,Zr and Y).Their trace elements and REE patterns are similar,indicating that they are co-genetic.They are characterized by high fractionation factor(La/Yb)N(3.04-228.44)and pronounced negative Eu anomalies(Eu/Eu*)(0.23-0.71).Their overall geochemical features indicate that they were most likely derived from partial melting of crustal materials in an orogenic(post-collisional)tectonic setting.They are therefore related to the Pan-African granites,otherwise known as the Older Granites which were emplaced during the Pan African orogenic event. 展开更多
关键词 Pan African Partial melting POST-COLLISIONAL PRECAMBRIAN Older GRANITES OROGENIC
Contrasting sorption behaviours affecting groundwater arsenic concentration in Kandal Province,Cambodia 预览
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作者 Laura A. Richards Maria J. Casanueva-Marenco +3 位作者 Daniel Magnone Chansopheaktra Sovann Bart E. van Dongen David A. Polya 《地学前缘:英文版》 CAS CSCD 2019年第5期1701-1713,共13页
Natural arsenic (As) contamination of groundwater which provides drinking water and/or irrigation supplies remains a major public health issue,particularly in South and Southeast Asia.A number of studies have evaluate... Natural arsenic (As) contamination of groundwater which provides drinking water and/or irrigation supplies remains a major public health issue,particularly in South and Southeast Asia.A number of studies have evaluated various aspects of the biogeochemical controls on As mobilization in aquifers typical to this region,however many are predicated on the assumption that key biogeochemical processes may be deduced by sampled water chemistry.The validity of this assumption has not been clearly established even though the role of sorption/desorption of As and other heavy metals onto Fe/Mn (hydr) oxides is an important control in As mobilization.Here,selective chemical extractions of sand-rich and clay-rich sediments from an As-affected aquifer in Kandal Province,Cambodia,were undertaken to explore the potential role of partial re-equilibrium through sorption/desorption reactions of As and related solutes (Fe,Mn and P) between groundwater and the associated solid aquifer matrix.In general,groundwater As is strongly affected by both pH and Eh throughout the study area.However,contrasting sorption behaviour is observed in two distinct sand-dominated (T-Sand) and clay dominated (T-Clay) transects,and plausibly attributed to differing dominant lithologies,biogeochemical and/or hydrogeological conditions.Sorption/desorption processes appear to be re-setting groundwater As concentrations in both transects,but to varying extents and in different ways.In T-Sand,which is typically highly reducing,correlations suggest that dissolved As may be sequestered by sorption/re-adsorption to Fe-bearing mineral phases and/or sedimentary organic matter;in T-Clay Eh is a major control on As mobilization although binding/occlusion of Fe-bearing minerals to sedimentary organic matter may also occur.Multiple linear regression analysis was conducted with groups categorised by transect and by Eh,and the output correlations support the contrasting sorption behaviours encountered in this study area.Irrespective of transect,however,the key biogeoch 展开更多
关键词 ARSENIC Groundwater Partial EQUILIBRIUM SORPTION Water-rock interactions Cambodia
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HOLDER CONTINUITY FOR THE PARABOLIC ANDERSON MODEL WITH SPACE-TIME HOMOGENEOUS GAUSSIAN NOISE 预览
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作者 Raluca M BALAN Lluis Q UER-SARDANYONS 宋健 《数学物理学报:B辑英文版》 SCIE CSCD 2019年第3期717-730,共14页
In this article,we consider the Parabolic Anderson Model with constant initial condition,driven by a space-time homogeneous Gaussian noise,with general covariance function in time and spatial spectral measure satisfyi... In this article,we consider the Parabolic Anderson Model with constant initial condition,driven by a space-time homogeneous Gaussian noise,with general covariance function in time and spatial spectral measure satisfying Dalang's condition.First,we prove that the solution (in the Skorohod sense) exists and is continuous in Lp(Ω).Then,we show that the solution has a modification whose sample paths are H(o)lder continuous in space and time,under the minimal condition on the spatial spectral measure of the noise (which is the same as the condition encountered in the case of the white noise in time).This improves similar results which were obtained in [6,10] under more restrictive conditions,and with sub-optimal exponents for H(o)lder continuity. 展开更多
关键词 GAUSSIAN noise STOCHASTIC partial differential equations Malliavin CALCULUS
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Geochemistry, Zircon U-Pb Age and Hf Isotope of the Huilanshan Granitoids in the North Dabie Terrane: Implications for Syn-Collapse Magmatism of Orogen
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作者 Shengxin Liu Haijin Xu 《地球科学学刊:英文版》 SCIE CAS CSCD 2019年第3期636-646,共11页
Syn-collapse magmatism is a critical issue for evolution of the continental orogen.The Dabie Orogen is a typical orogen which was suffered from a complete collapse.Two kinds of granitoids,namely,the coarse-grained dio... Syn-collapse magmatism is a critical issue for evolution of the continental orogen.The Dabie Orogen is a typical orogen which was suffered from a complete collapse.Two kinds of granitoids,namely,the coarse-grained diorite and the fine-grained granite,are recognized at the center of the Luotian extensional dome,providing an opportunity to decipher the syn-collapse magmatism in the Dabie Orogen.The diorites(125±3 Ma)are high K calc-alkaline rocks,with low SiO2(51.9 wt.%–56.6 wt.%)and high MgO(3.5 wt.%–4.0 wt.%)contents.They are enriched in LREE and LILEs(e.g.,Ba,K,Rb)and depleted in HFSEs(e.g.,Ta,Nb,and Hf)with low ratio of Sr/Y(30.82–46.89).The granites(118±2 Ma)are shoshonite series rocks,with relatively high SiO2(68.9 wt.%–72.6 wt.%)and low MgO(0.32 wt.%–0.66 wt.%)contents.They are also enriched in LREE and LILEs with weakly negative Eu anomalies(δEu=0.81–0.85),and are depleted in HFSEs with low Sr contents(338 ppm–477 ppm)and Sr/Y ratios(23.80–33.13).Therefore,the two kinds of granitoids have no geochemical characteristics of adakitic rocks,suggesting that they were generated from a normal or thinned crust level.The diorites have quite negative zirconεHf(t)values(-18.4 to-21.1),suggesting they were from partial melting of the mafic lower continental crust.The granites have relatively higher zirconεHf(t)values(-14.4 to-18.1).The granites also contains a series of old inherited zircon cores,such as two upper intercept ages of 2 628±41 and 1 840±37 Ma,and a concordant age of 807±9 Ma.All these features suggest that the granites were generated from partial melting of the felsic middle-lower continental crust.Thus,the Huilanshan Early Cretaceous granitoids coupled with the Luotian extensional dome revealed the collapsed process of the Dabie Orogen. 展开更多
关键词 orogenic collapse MAGMATISM partial melting lower continental crust DABIE OROGEN
Study of spatial and temporal evolution of Ar and F atoms in SF6/Ar microsecond pulsed discharge by optical emission spectroscopy
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作者 李红月 吴兴伟 +5 位作者 李聪 王勇 吴鼎 刘佳敏 冯春雷 丁洪斌 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第7期69-76,共8页
The study of sulfur hexafluoride(SF6) discharge is vital for its application in gas-insulated equipment. Direct current partial discharge(PD) may cause SF6 decomposition, and the decomposed products of SF6, such as F ... The study of sulfur hexafluoride(SF6) discharge is vital for its application in gas-insulated equipment. Direct current partial discharge(PD) may cause SF6 decomposition, and the decomposed products of SF6, such as F atoms, play a dominant role in the breakdown of insulation systems. In this study, the PD caused by metal protrusion defects is simulated by a needle-plate electrode using pulsed high voltage in SF6/Ar mixtures. The spatial and temporal characteristics of SF6/Ar plasma are analyzed by measuring the emission spectra of F and Ar atoms, which are important for understanding the characteristics of PD. The spatial resolved results show that both F and Ar atom spectral intensities increase first from the plate anode to the needle and then decrease under the conditions of a background pressure of400 Pa, peak voltage of-1000 V, frequency of 2 kHz, pulse width of 60 μs, and electrode gap of 5-9 mm. However, the distribution characteristics of F and Ar are significantly different. The temporal distribution results show that the spectral intensity of Ar decreasesfirst and then increases slowly, while the spectral intensity of F increases slowly for the duration of the pulsed discharge at the electrode gap of 5 mm and the pulse width of40-80 μs. 展开更多
关键词 optical emission spectroscopy partial discharge SF6-insulated equipment SPATIAL and TEMPORAL evolution
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