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The Application of Differential Characteristic Set Method to Pseudo Differential Operator and Lax Representation
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作者 Yifeng JIA Dongliang XIAO 《数学研究及应用:英文版》 CSCD 2019年第2期196-220,共25页
Differential characteristic set method is applied to the calculation of pseudo differential operators and Lax representation of nonlinear evolution equations. Firstly, differential characteristic set method and differ... Differential characteristic set method is applied to the calculation of pseudo differential operators and Lax representation of nonlinear evolution equations. Firstly, differential characteristic set method and differential division with remainder are used for the calculation of inverse and extraction root of pseudo differential operator, such that the process is simplified since it is unnecessary to solve ordinary differential equation systems and substitute the solutions.Secondly, using differential characteristic set method, the nonlinear partial differential equation systems derived from the generalized Lax equation and Zakharov-Shabat equation, are reduced,and the corresponding nonlinear evolution equation is obtained. The related programs are compiled in Mathematica, a computer-based computer algebra system, and Lax representation of some nonlinear evolution equations can be calculated with the aid of the computer. 展开更多
关键词 DIFFERENTIAL characteristic set DIFFERENTIAL division with REMAINDER PSEUDO DIFFERENTIAL operator LAX representation Zakharov-Shabat equation
Elimination Theory in Differential and Difference Algebra
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作者 LI Wei YUAN Chun-Ming 《系统科学与复杂性学报:英文版》 SCIE EI CSCD 2019年第1期287-316,共30页
Elimination theory is central in differential and difference algebra. The Wu-Ritt characteristic set method, the resultant and the Chow form are three fundamental tools in the elimination theory for algebraic differen... Elimination theory is central in differential and difference algebra. The Wu-Ritt characteristic set method, the resultant and the Chow form are three fundamental tools in the elimination theory for algebraic differential or difference equations. In this paper, the authors mainly present a survey of the existing work on the theory of characteristic set methods for differential and difference systems,the theory of differential Chow forms, and the theory of sparse differential and difference resultants. 展开更多
关键词 DIFFERENTIAL Chow forms DIFFERENTIAL RESULTANTS SPARSE DIFFERENTIAL RESULTANTS Wu-Ritt characteristic SETS
Vertical profile of aerosol extinction based on the measurement of O4 of multi-elevation angles with MAX-DOAS
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作者 牟福生 雒静 +2 位作者 李素文 单巍 胡丽莎 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第8期195-200,共6页
A method for aerosol extinction profile retrieval using ground-based multi-axis differential optical absorption spectroscopy(MAX-DOAS)is studied,which is based on a look-up table algorithm.The algorithm uses parametri... A method for aerosol extinction profile retrieval using ground-based multi-axis differential optical absorption spectroscopy(MAX-DOAS)is studied,which is based on a look-up table algorithm.The algorithm uses parametric method to represent aerosol extinction profiles and simulate different atmospheric aerosol states through atmospheric radiation transfer model.Based on the method,aerosol extinction profile was obtained during six cloud-free days.The O4 differential air mass factor(dAMF)measured by MAX-DOAS is compared with the corresponding model results under different atmospheric conditions(R^2=0.78).The aerosol optical thickness,aerosol weight factor in boundary layer,and the height of the boundary layer are obtained after the process of minimization and look-up table method.The retrieved aerosol extinction in boundary layer is compared with PM2.5 data measured by ground point instrument.The diurnal variation trends of the two methods are in good agreement.The correlation coefficients of the two methods are 0.71 when the aerosol optical thickness is smaller than 0.5.The results show that the look-up table method can obtain the aerosol state of the troposphere and provide validation for other instrument data. 展开更多
关键词 vertical profile of AEROSOL EXTINCTION look-up TABLE O4 DIFFERENTIAL air mass factor MULTI-AXIS DIFFERENTIAL optical absorption SPECTROSCOPY
REFLECTED BACKWARD STOCHASTIC DIFFERENTIAL EQUATION WITH JUMPS AND VISCOSITY SOLUTION OF SECOND ORDER INTEGRO-DIFFERENTIAL EQUATION WITHOUT MONOTONICITY CONDITION: CASE WITH THE MEASURE OF LEVY INFINITE 预览
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作者 Lamine SYLLA 《数学物理学报:B辑英文版》 SCIE CSCD 2019年第3期819-844,共26页
We consider the problem of viscosity solution of integro-partial differential equation( IPDE in short) with one obstacle via the solution of reflected backward stochastic dif ferential equations(RBSDE in short) with j... We consider the problem of viscosity solution of integro-partial differential equation( IPDE in short) with one obstacle via the solution of reflected backward stochastic dif ferential equations(RBSDE in short) with jumps. We show the existence and uniqueness of a continuous viscosity solution of equation with non local terms, if the generator is not monotonous and Levy's measure is infinite. 展开更多
关键词 Integro-partial DIFFERENTIAL equation reflected stochastic DIFFERENTIAL equations with JUMPS viscosity solution NON-LOCAL operator
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UNIQUENESS PROBLEM FOR SPDES FROM POPULATION MODELS 预览
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作者 熊捷 杨叙 《数学物理学报:B辑英文版》 SCIE CSCD 2019年第3期845-856,共12页
This is a survey on the strong uniqueness of the solutions to stochastic partial differential equations (SPDEs) related to two measure-valued processes: superprocess and Fleming-Viot process which are given as rescali... This is a survey on the strong uniqueness of the solutions to stochastic partial differential equations (SPDEs) related to two measure-valued processes: superprocess and Fleming-Viot process which are given as rescaling limits of population biology models. We summarize recent results for Konno-Shiga-Reimers1 and Mytnik's SPDEs, and their related distribution-function-valued SPDEs. 展开更多
关键词 STOCHASTIC partial DIFFERENTIAL EQUATION SUPERPROCESS Fleming-Viot process distribution function backward doubly STOCHASTIC DIFFERENTIAL EQUATION pathwise UNIQUENESS
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Neural network as a function approximator and its application in solving differential equations 预览
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作者 Zeyu LIU Yantao YANG Qingdong CAI 《应用数学和力学:英文版》 SCIE EI CSCD 2019年第2期237-248,共12页
A neural network(NN)is a powerful tool for approximating bounded continuous functions in machine learning.The NN provides a framework for numerically solving ordinary differential equations(ODEs)and partial differenti... A neural network(NN)is a powerful tool for approximating bounded continuous functions in machine learning.The NN provides a framework for numerically solving ordinary differential equations(ODEs)and partial differential equations(PDEs)combined with the automatic differentiation(AD)technique.In this work,we explore the use of NN for the function approximation and propose a universal solver for ODEs and PDEs.The solver is tested for initial value problems and boundary value problems of ODEs,and the results exhibit high accuracy for not only the unknown functions but also their derivatives.The same strategy can be used to construct a PDE solver based on collocation points instead of a mesh,which is tested with the Burgers equation and the heat equation(i.e.,the Laplace equation). 展开更多
关键词 neural network(NN) FUNCTION approximation ordinary DIFFERENTIAL equation(ODE)solver partial DIFFERENTIAL equation(PDE)solver
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STUDY OF THE STABILITY BEHAVIOUR AND THE BOUNDEDNESS OF SOLUTIONS TO A CERTAIN THIRD-ORDER DIFFERENTIAL EQUATION WITH A RETARDED ARGUMENT
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作者 A.M.Mahmoud D.A.M.Bakhit 《应用数学年刊:英文版》 2019年第1期99-110,共12页
Lyapunov direct method is employed to investigate the asymptotic behaviour and the boundedness of solutions to a certain third-order differential equation with delay and some new results are obtained. Our results impr... Lyapunov direct method is employed to investigate the asymptotic behaviour and the boundedness of solutions to a certain third-order differential equation with delay and some new results are obtained. Our results improve and complement some earlier results. Two examples are given to illustrate the importance of the topic and the main results obtained. 展开更多
关键词 delay DIFFERENTIAL EQUATIONS asymptotic BEHAVIOUR stability THIRD-ORDER DIFFERENTIAL EQUATIONS Lyapunov functional
Path independence of additive functionals for stochastic differential equations under G-framework
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作者 Panpan REN Fen-Fen YANG 《中国数学前沿:英文版》 SCIE CSCD 2019年第1期135-148,共14页
The path independence of additive functionals for stochastic differential equations (SDEs) driven by the G-Brownian motion is characterized by the nonlinear partial differential equations. The main result generalizes ... The path independence of additive functionals for stochastic differential equations (SDEs) driven by the G-Brownian motion is characterized by the nonlinear partial differential equations. The main result generalizes the existing ones for SDEs driven by the standard Brownian motion. 展开更多
关键词 Stochastic DIFFERENTIAL EQUATION (SDE) partial DIFFERENTIAL EQUATION (PDE) additive functional G-SDEs G-Brownian motion nonlinear PDE
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
Differential evolution based computation intelligence solver for elliptic partial differential equations
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作者 Muhammad Faisal FATEH Aneela ZAMEER +3 位作者 Sikander MMIRZA Nasir MMIRZA Muhammad Saeed ASLAM Muhammad Asif Zahoor RAJA 《信息与电子工程前沿:英文版》 SCIE EI CSCD 2019年第10期1445-1456,共12页
A differential evolution based methodology is introduced for the solution of elliptic partial differential equations (PDEs) with Dirichlet and/or Neumann boundary conditions. The solutions evolve over bounded domains ... A differential evolution based methodology is introduced for the solution of elliptic partial differential equations (PDEs) with Dirichlet and/or Neumann boundary conditions. The solutions evolve over bounded domains throughout the interior nodes by minimization of nodal deviations among the population. The elliptic PDEs are replaced by the corresponding system of finite difference approximation, yielding an expression for nodal residues. The global residue is declared as the root-mean-square value of the nodal residues and taken as the cost function. The standard differential evolution is then used for the solution of elliptic PDEs by conversion to a minimization problem of the global residue. A set of benchmark problems consisting of both linear and nonlinear elliptic PDEs has been considered for validation, proving the effectiveness of the proposed algorithm. To demonstrate its robustness, sensitivity analysis has been carried out for various differential evolution operators and parameters. Comparison of the differential evolution based computed nodal values with the corresponding data obtained using the exact analytical expressions shows the accuracy and convergence of the proposed methodology. 展开更多
关键词 Differential evolution Boundary value problems Partial differential equation Finite difference scheme Numerical computing
A New Distinguishing Attack on Grain-V1 with 111 Initialization Rounds
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作者 MA Zhen TIAN Tian QI Wenfeng 《系统科学与复杂性学报:英文版》 SCIE EI CSCD 2019年第3期970-984,共15页
The Grain-v1 stream cipher has been selected in the eSTREAM hardware finalists. In this paper, the authors derive a new distinguishing attack on Grain-v1 with 111 initialization rounds in a single-key setting. To achi... The Grain-v1 stream cipher has been selected in the eSTREAM hardware finalists. In this paper, the authors derive a new distinguishing attack on Grain-v1 with 111 initialization rounds in a single-key setting. To achieve this goal, the authors present two delicate strategies targeting an obvious distinguishing probability of the output difference of reduced Grain-v1. The authors show that conditional differential cryptanalysis of reduced Grain-v1 with 111 initialization rounds could mount a distinguishing attack with success probability about 0.8281 for all secret keys. It is also shown that when the attacking round further increases to 112 and 113, the distributions of the output differences are nearly random. Thus far, to the best of the authors' knowledge, the attack on Grain-v1 with 111 initialization rounds is the best single-key cryptanalytic result for reduced versions of Grain-vl in terms of the number of attacking rounds. 展开更多
关键词 CRYPTANALYSIS differential CRYPTANALYSIS distinguishing ATTACK Grain-v1 stream CIPHER
Reconstructed Elzaki Transform Method for Delay Differential Equations with Mamadu-Njoseh Polynomials 预览
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作者 E. J. Mamadu H. I. Ojarikre 《数学和系统科学:英文版》 2019年第2期41-45,共5页
One of the solution techniques used for ordinary differential equations, partial and integral equations is the Elzaki Transform. This paper is an extension of Mamadu and Njoseh [1] numerical procedure (Elzaki transfor... One of the solution techniques used for ordinary differential equations, partial and integral equations is the Elzaki Transform. This paper is an extension of Mamadu and Njoseh [1] numerical procedure (Elzaki transform method (ETM)) for computing delay differential equations (DDEs). Here, a reconstructed Elzaki transform method (RETM) is proposed for the solution of DDEs where Mamadu-Njoseh polynomials are applied as basis functions in the approximation of the analytic solution. Using this strategy, a numerical illustration as in Ref.[1] is provided to the RETM as a basis for comparison to guarantee accuracy and consistency of the method. All numerical computations were performed with MAPLE 18 software. 展开更多
关键词 Elzaki TRANSFORM method Mamadu-Njoseh POLYNOMIALS DELAY DIFFERENTIAL EQUATIONS
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Analysis of the Oldest Carbonate Gas Reservoir in China——New Geological Significance of the Dengying Gas Reservoir in the Weiyuan Structure, Sichuan Basin
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作者 Xiao Liang Shugen Liu +3 位作者 Shubei Wang Bin Deng Siyu Zhou Wenxin Ma 《地球科学学刊:英文版》 SCIE CAS CSCD 2019年第2期348-366,共19页
The Weiyuan Structure is the largest surface structure in the Sichuan Basin. However, the abundance of the Dengying Formation gas reservoir in the Weiyuan Structure is low. The height of the gas column is 244 m, but t... The Weiyuan Structure is the largest surface structure in the Sichuan Basin. However, the abundance of the Dengying Formation gas reservoir in the Weiyuan Structure is low. The height of the gas column is 244 m, but the integrated abundance is only 26.4%. After nearly 40 years of exploration, the Gaoshi1 Well and Moxi8 Well yielded gas flows that marked an important exploration success after the discovery of the Sinian Dengying Formation gas reservoir in the Weiyuan Structure, Sichuan Basin, Lower-Paleozoic in 1964. Combined with research examples of oil and gas migration and gas chimneys around the world, the authors used comprehensive geological-geophysical-geochemical research methods to provide a reasonable explanation of the low abundance of the gas reservoir in the Weiyuan Structure based on the surface and subsurface data. The latest research results show that(1) currently, the Weiyuan Structure is the apex of the Dengying Formation in the Mid-Sichuan Basin. The Guang’an, Longnüsi, Gaoshiti-Moxi, and Weiyuan structures are a series of traps in the Dengying Formation with gradual uplifting spill and closure points during the regional uplift of the Himalayan period. The natural gas of the Dengying Formation accumulated in different ways over a wide range and long distance in the Sichuan Basin.(2) At approximately 40 Ma, the Weiyuan area started to uplift and form the present structure, and it is the only outcropped area with the Triassic Jialingjiang Formation and Leikoupo Formation in the surface of the Sichuan Basin(except the steep structural belt in East Sichuan). Caused by the uplift and denudation, the core of the Weiyuan Structure has formed an escaping 'skylight' for natural gas. The evidence of a gas chimney includes(1) the component percentage of non-hydrocarbon gas, which decreased from the bottom to the top,(2) the pressure coefficient is normal because the gas reservoir from the Upper Sinian to the Lower Permian commonly have a normal pressure coefficient(an average of 1.0), and(3) the isotop 展开更多
关键词 SICHUAN Basin Weiyuan STRUCTURE Dengying Formation LATE reconstruction differential ACCUMULATION gas CHIMNEY
多种MRI参数联合诊断肿块型肉芽肿性乳腺炎的Logistic分析 预览
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作者 刘德樟 刘翠钰 +2 位作者 周小忠 黄健书 李狄航 《放射学实践》 北大核心 2019年第6期640-645,共6页
目的:探讨多种MRI参数联合对肿块型肉芽肿性乳腺炎(MTGM)与浸润性导管癌(IDC)鉴别诊断的意义。方法:回顾性分析经手术病理证实的17例肿块型MTGM和51例IDC患者的临床及MRI资料,比较两组在年龄、发病部位、大小、形状、边界、临近皮肤增... 目的:探讨多种MRI参数联合对肿块型肉芽肿性乳腺炎(MTGM)与浸润性导管癌(IDC)鉴别诊断的意义。方法:回顾性分析经手术病理证实的17例肿块型MTGM和51例IDC患者的临床及MRI资料,比较两组在年龄、发病部位、大小、形状、边界、临近皮肤增厚、同侧腋窝淋巴结肿大、增强曲线类型、内部环形强化、DWI信号、ADC值的差异,并采用单因素及多因素分析法进行统计学分析。结果:与IDC组比较,MTGM组病灶多发生于乳晕后区(10/17vs15/51,P=0.029),多引起周围皮肤水肿增厚(13/17vs24/51,P=0.035),增强扫描多见环形强化灶(11/17vs13/51,P=0.003),病灶内部液性区(T2WI高信号)的ADC值明显减低[(0.994±0.249)vs(1.762±0.545)×10^-3mm^2/s,P=0.001]。另外以上述征象为变量建立Logistic回归模型,筛选出肿块内部环形强化、液性区域的ADC值为预测MTGM的危险因素(P<0.05);2个因素联合预测MTGM的ROC曲线下面积为0.913。结论:肿块内部环形强化、液性区域的ADC值是预测MTGM的独立危险因素,联合应用可以提高MTGM的诊断符合率。 展开更多
关键词 肉芽肿性乳腺炎 乳腺肿瘤 磁共振成像 诊断 鉴别
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莫迪司MRI增强扫描在周围性胆管细胞癌及肝脓肿鉴别诊断中应用 预览
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作者 汪俐杉 汤化民 +1 位作者 陈宝 李娜 《放射学实践》 北大核心 2019年第6期646-650,共5页
目的:探讨莫迪司MRI增强扫描在周围性胆管细胞癌及肝脓肿鉴别诊断中的价值,以减少误诊。方法:回顾性搜集经病理证实的22例肝脓肿及21例周围性胆管细胞癌,所有病例均行莫迪司MRI平扫和增强扫描,对比分析2组MRI表现差异。结果:周围性胆管... 目的:探讨莫迪司MRI增强扫描在周围性胆管细胞癌及肝脓肿鉴别诊断中的价值,以减少误诊。方法:回顾性搜集经病理证实的22例肝脓肿及21例周围性胆管细胞癌,所有病例均行莫迪司MRI平扫和增强扫描,对比分析2组MRI表现差异。结果:周围性胆管细胞癌与肝脓肿在病灶形态、信号均匀性、边缘方面差异无统计学意义(P>0.05);2组病灶增强扫描多为渐进性强化,且DWI呈高信号,差异无统计学意义(P>0.05);2组病灶伴随征象(邻近胆管扩张、胆管结石、异常灌注及肝包膜回缩)发生率差异无统计学意义(P>0.05);肝胆期,周围性胆管细胞癌外周部呈相对低信号18例(18/21),肝脓肿外周部呈均高信号(22/22),二者比较有统计学意义(P<0.05)。结论:肝胆期,周围性胆管细胞癌外周部强化减低,而肝脓肿外周部呈持续强化,具有重要的诊断价值。 展开更多
关键词 莫迪司 胆管细胞癌 肝脓肿 诊断 鉴别 磁共振成像
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磁共振动态对比增强联合扩散加权成像鉴别脑高级别胶质瘤复发和治疗后反应的初步研究 预览
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作者 任龙飞 张辉 +2 位作者 王效春 谭艳 秦江波 《磁共振成像》 CAS 2019年第9期655-660,共6页
目的探讨磁共振动态对比增强和扩散加权成像在鉴别高级别胶质瘤复发和治疗后反应的应用价值。材料与方法收集脑胶质瘤全切术+同步放化疗术后出现异常强化灶的患者32例(22例为肿瘤复发,10例为治疗后反应),放化疗结束2个月内行常规MRI平... 目的探讨磁共振动态对比增强和扩散加权成像在鉴别高级别胶质瘤复发和治疗后反应的应用价值。材料与方法收集脑胶质瘤全切术+同步放化疗术后出现异常强化灶的患者32例(22例为肿瘤复发,10例为治疗后反应),放化疗结束2个月内行常规MRI平扫及增强、DWI、DCE灌注成像,经后处理获得Ktrans、Kep、Ve、iAUC灌注伪彩图及ADC图,分别测量患者异常强化区Ktrans值、Kep值、Ve值、iAUC值及平均ADC值,应用秩和检验检验分析两组间各参数差异,对具有统计学意义的参数值绘制受试者工作特征(receiver operating characteristic,ROC)曲线,分别计算敏感度、特异度及曲线下面积。结果复发组Ktrans值、iAUC值均高于治疗后反应组,差异有统计学意义(P<0.05),Ve及Kep在两组间差异均无统计学意义(P>0.05)。Roc曲线分析,当Ktrans值、iAUC值曲线下面积分别为0.973、0.941时,灵敏度均为95.5%,特异度分别为90%、80%。复发组ADC平均值低于治疗后反应组,差异有统计学意义(P<0.05)。Roc曲线分析,当平均ADC值曲线下面积为0.864时,灵敏度及特异度分别为86.4%、80%。且Ktrans诊断效能高于iAUC及平均ADC值,并联试验中使用Ktrans联合ADC诊断胶质瘤复发灵敏度可提高至100%。结论 DCE-MRI联合DWI在胶质瘤复发和治疗后反应的鉴别诊断中具有重要的临床应用价值。 展开更多
关键词 神经胶质瘤 复发 磁共振成像 诊断 鉴别
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Jensen’s Inequality Under Nonlinear Expectation Generated by BSDE with Jumps
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作者 Na ZHANG Guang-yan JIA 《应用数学学报:英文版》 CSCD 2019年第4期873-884,共12页
In this paper, we study Jensen’s inequality under f-expectation, which is a nonlinear expectation generated by backward stochastic differential equations(BSDEs) with jumps. We connect f-convex functions with the visc... In this paper, we study Jensen’s inequality under f-expectation, which is a nonlinear expectation generated by backward stochastic differential equations(BSDEs) with jumps. We connect f-convex functions with the viscosity solutions of a kind of integral partial differential equations(IPDEs) with non-local terms.And find that under Lipschitz condition, the f-convex function is still convex in the usual sense, i.e., the jumps shrink the range of ‘convex’ functions. 展开更多
关键词 BACKWARD stochastic differential equation with JUMPS f-convexity Jensen’s INEQUALITY
基于Pro/E的汽车差速器装配与机构仿真 预览
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作者 林新英 林宗德 刘伟 《数字技术与应用》 2019年第6期93-94,共2页
介绍了差速器的结构组成和工作原理,按照装配关系将各元件连接组装并建立连接,借助Pro/E的机构仿真建立差速器运动分析和动力分析,获取分析结果,验证了差速器的工作原理和运动规律。
关键词 PRO/E 差速器 机构仿真分析
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甲状腺细针穿刺吸取细胞学标本中miR-221与miR-222对良恶性甲状腺结节的诊断价值研究 预览
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作者 闫永鑫 徐宁 王国凤 《中国全科医学》 CAS 北大核心 2019年第30期3731-3735,共5页
背景甲状腺结节是一种常见的临床问题,甲状腺细针穿刺吸取细胞学(FNAC)检查是临床常用的诊断良恶性甲状腺结节的检查方法,但15%~30%的患者无法确切诊断。因此,临床上迫切需要能有效帮助鉴别诊断良恶性甲状腺结节的生物学标志物。目的探... 背景甲状腺结节是一种常见的临床问题,甲状腺细针穿刺吸取细胞学(FNAC)检查是临床常用的诊断良恶性甲状腺结节的检查方法,但15%~30%的患者无法确切诊断。因此,临床上迫切需要能有效帮助鉴别诊断良恶性甲状腺结节的生物学标志物。目的探讨良恶性甲状腺结节患者甲状腺FNAC检查标本中miR-221、miR-222的表达水平及其对良恶性甲状腺结节的诊断价值。方法选取2015年3月-2017年12月就诊于南京医科大学康达学院第一附属医院符合研究标准的甲状腺结节患者60例。患者均经甲状腺FNAC检查,初次诊断为恶性病变17例,良性病变34例,可疑恶性、未诊断病变5例,滤泡性病变2例,滤泡性肿瘤2例。比较初次诊断为良性病变和恶性病变患者的甲状腺FNAC检查标本中miR-221、miR-222表达水平。以术后病理检查结果为金标准,绘制甲状腺FNAC检查标本中miR-221、miR-222诊断恶性甲状腺结节的受试者工作特征曲线(ROC曲线),并计算ROC曲线下面积(AUC),最佳截断值、灵敏度、特异度。计算甲状腺FNAC检查结果联合甲状腺FNAC检查标本中miR-221、miR-222诊断甲状腺结节的符合率。并比较不同一般资料患者甲状腺FNAC检查标本中miR-221、miR-222表达水平。结果 60例患者经甲状腺术后病理检查示,良性结节51例,恶性结节9例。恶性结节患者FANC检查中miR-221、miR-222表达水平高于良性结节患者(P<0.05)。甲状腺FNAC检查标本中miR-221诊断恶性甲状腺结节的AUC为0.774(0.691,0.858),其最佳截断值为2.77,灵敏度为80%,特异度为60.0%,约登指数为0.400。甲状腺FNAC检查标本中miR-222诊断恶性甲状腺结节的AUC为0.759(0.672,0.845),其最佳截断值为2.73,灵敏度为76.7%,特异度为66.7%,约登指数为0.443。甲状腺FNAC检查结果联合甲状腺FNAC检查标本中miR-221、miR-222诊断甲状腺结节与术后病理检查结果的符合率为80.0%。不同性别、年龄、肿瘤最大径、� 展开更多
关键词 甲状腺结节 微RNAS MIR-221 MIR-222 甲状腺细针穿刺 诊断 鉴别
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600MW发电机组励磁变故障分析 预览
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作者 钟振坤 骆华志 《电工技术》 2019年第3期77-79,共3页
针对600MW发电机组励磁变差动故障的过程,对现场检查结果进行了分析,并综合各保护装置和故障录波仪的数据图表进行协同研究,准确地推断出故障点。根据故障原因进行有针对性的改进,避免类似大型干式变压器再次发生故障。
关键词 励磁变 差动 故障录波 电气量相角
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