检索结果-南通市图书馆

Journal of Systems Science & Complexity 2014年第2期27卷 276-288页

作者： SUN Yudong shi Yimin GU xin Department of Applied Mathematics Northwestern Polytechnical University Department of Methodology and Statistics Utrecht University

This paper studies the nonlinear variational inequality with integro-differential term arising from valuation of American style double barrier option. First, the authors use the penalty method to transform the variational inequality into a nonlinear parabolic initial boundary problem(i.e., penalty problem). Second, the existence and uniqueness of solution to the penalty problem are proved by using the Scheafer fixed point theory. Third, the authors prove the existence of variational inequality' solution by showing the fact that the penalized PDE converges to the variational inequality. The uniqueness of solution to the variational inequality is also proved by contradiction.

关键词： American style barrier option existence integro-differential uniqueness variational inequality.

Methods of reduction for Lagrange systems on time scales with nabla derivatives

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2017年第1期26卷 243-249页

作者： shi-xin Jin Yi Zhang School of Science Nanjing University of Science and Technology Nanjing 210009 China College of Civil Engineering Suzhou University of Science and Technology Suzhou 215011 China

The Routh and Whittaker methods of reduction for Lagrange system on time scales with nabla derivatives are *** equations of motion for Lagrange system on time scales are established, and their cyclic integrals and generalized energy integrals are given. The Routh functions and Whittaker functions of Lagrange system are constructed, and the order of differential equations of motion for the system are reduced by using the cyclic integrals or the generalized energy integrals with nabla derivatives. The results show that the reduced Routh equations and Whittaker equations hold the form of Lagrnage equations with nabla derivatives. Finally, two examples are given to illustrate the application of the results.

关键词： reduction of dynamical system cyclic integral energy integral time scales

Upconversion multicolor tuning of NaY(WO_4)_2:Tb^(3+) with Eu^(3+) doping

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2018年第9期36卷 911-916页

作者： Zhongxiang shi Jing Wang xin Guan Liaoning Key Laboratory for Fabrication and Application of Superfine Inorganic Powders Dalian Jiaotong University

A series of Tb3＋ and Eu3＋ co-doped NaY（WO4）2 phosphors were synthesized by hydrothermal *** crystal structure,morphology,upconversion luminescent properties,the energy transfer from Tb3＋ to Eu3＋ions and the 5 D4→ 7 F5 transition of the Tb3＋ ion in NaY（WO4）2：Tb3＋,Eu3＋ phosphors were investigated in *** results indicate that all the synthesized samples are of pure tetragonal phase NaY（WO4）***,the micrometer-sized needle spheres and excellent dispersion of the particles are obtained by adding polyethylene glycol（PEG-2000） as the *** of NaY（WO4）2：Tb3＋,Eu3＋ exhibit the492 nm blue emission peak,546 nm green emission peak,595 nm orange emission peak and 616 nm red emission peak under 790 nm *** energy transfer from Tb3＋ to Eu3＋ is a resonant transfer,in which electric dipole-dipole interaction plays a leading *** adjusting the doping concentration of Eu3＋ in NaY（WO4）2： 1.0 mol%Tb3＋,xmol%Eu3＋ phosphors,the emitting color of UC phosphors can be tuned from green to red.

关键词： Up-conversion luminescence NaY(WO4)2:Tb^3+ Eu^3+ Polyethylene glycol Energy transfer Rare earths

Long-term Evolution of Solar Activity and Prediction of the Following Solar Cycles

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第3期24卷 194-204页

作者： Pei-xin luo Bao-Lin Tan National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China

Solar activities have a great impact on modern high-tech systems,such as human aerospace activities,satellite communication and navigation,deep space exploration,and related scientific ***,studying the long-term evolution trend of solar activity and accurately predicting the future solar cycles are highly *** on the wavelet transform and empirical function fitting of the longest recorded data of the annual average relative sunspot number(ASN)series of 323 yr to date,this work decisively verifies the existence of the solar century cycles and confirms that its length is about 104.0 yr,and the magnitude has a slightly increasing trend on the timescale of several hundred *** on this long-term evolutionary trend,we predict solar cycles 25 and26 by using phase similar prediction *** for solar cycle 25,its maximum ASN will be about146.7±33.40,obviously stronger than solar cycle *** peak year will occur approximately in 2024,and the period will be about 11±1 *** for solar cycle 26,it will start around 2030,and reach its maximum between2035 and 2036,with maximum ASN of about 133.0±3.200,and period of about 10 yr.

关键词： Sun activity-Sun evolution-(Sun) sunspots-methods data analysis

NUMERICAL SIMULATION OF ATOMIZATION RAINFALL AND THE GENERATED FLOW ON A SLOPE

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2012年第2期24卷 273-279页

作者： LIU shi-he TAI Wei FAN Min luo Qiu-shi State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan430072 China Yellow River Engineering Consulting Co. Ltd Zhengzhou 450003 China

This article studies the atomization rainfall and the generated flow on a slope by numerical *** atomization rainfall is simulated by a unified model for splash droplets and a suspended mist,and the distribution of the diameter of splash rain drops is *** slope runoff generated by the atomization rainfall is simulated by a depth-averaged 2-D model,and the localization of the rainfall intensity in space is specially *** simulation results show that：（1） the median rain size of the atomization rainfall increases in the longitudinal direction at first,then monotonously decreases,and the maximum value is taken at the longitudinal position not in consistent with the position where the maximum rain intensity is *** the lateral direction the median rain size monotonously decreases,（2） since the atomization rainfall is distributed in a strongly localized area,it takes a longer time for its runoff yield to reach a steady state than that in the natural rainfall,the variation ranges of the water depth and the velocity in the longitudinal and lateral directions are larger than those in the natural rainfall.

关键词： atomized flow unified model slope runoff numerical simulation

A novel MMSE based codebook construction for MIMO precoded spatial multiplexing with limited feedback

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第12期8卷 1894-1900页

作者： SHE Feng luo Han-wen WANG xin Department of Electronic Engineering Shanghai Jiao Tong University Shanghai 200240 China

This paper deals with the design and performance analysis of the transmission precoder optimization for multiple-input multiple-output (MIMO) systems with limited feedback of channel state information (CSI). We assume that the receiver can get perfect channel knowledge by channel estimation while the transmitter only has partial channel knowledge from limited feedback. We present a minimum mean square error (MMSE) criterion based codebook construction algorithm for MIMO pre- coded spatial multiplexing systems under a specific average power constraint. The optimal transmitter structure is employed in this paper. Simulation results show that the MMSE criteria based codebook construction algorithm with hybrid design of power allocation and precoding can achieve better performance than that of equal power allocation based codebook of previous research.

关键词： Multiple-input multiple-output (MIMO) Precoding Channel state information (CSI) Feedback

Slip in Couette flow with pressure gradient:Theoretical and experimental investigation of hydrodynamic characteristics considering slip effect

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2020年第1期32卷 107-115页

作者： xin Zhao Chao Wei shi-hua Yuan Science and Technology on Vehicle Transmission Laborator Bejing Institute of TechnologyBeijing 10081China

A new slip velocity model based on molecular potential theory and macro-force analysis,which is applied in Couette flow with pressure gradient,is built *** model is validated by later being introduced in hydrodynamic system to predict film distribution,which shows a good agreement with experimental data obtained from multi-beam intensity-based tests with Fe and Cu ball materials under accurate controlled temperature,load and different wall *** show that the slip length for Fe case is ignorable so it seems like no slip,but for Cu case,the slip length is large to make 20%discrepancy with no slip simulation and also behaves ***,during the experimental cases when both Fe and Cu ball velocities rise from-133 mm/s to 1330 mm/s,the slip velocity changes its direction with entrainment velocity and thus contributes to first enhance and then diminish the hydrodynamic film,but due to slip length on Cu case varying largely than that on Fe case,the film from Cu case and from Fe case has a clear cross-point between uh=80 mm/s and uh=220 m m/s(ub is the ball speed).The results above support strongly that Cu surface will lead to stronger slip than Fe case because of its smaller solid-liquid interaction,and obviously slip will influence hydrodynamic characteristics prominently.

关键词： Slip Couette flow with pressure gradient hydrodynamic characteristic

The Challenge and promise of rare disease diagnosis in China

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2017年第7期60卷 681-685页

作者： xin Ni Tieliu shi Otolaryngology Head and Neck Surgery Beijing Children's Hospital Capital Medical University National Center for Children's Health Beijing 100045 China Beijing Key Laboratory for Pediatric Diseases of Otolaryngology Head and Neck Surgery Beijing Pediatric Research Institute Beijing Children's Hospital Capital Medical University National Center for Children's Health Beijing 100045 China The Center for Bioinformatics and Computational Biology Shanghai Key Laboratory of Regulatory Biology the Institute of Biomedical Sciences and School of Life Sciences East China Normal University Shanghai 200241 China

Rare diseases are chronic and serious,featuring early onset at birth or in childhood,rapid deterioration and high mortality rate,which creates a burden on society and public health *** the known rare diseases,80 percent are genetic in origin,and half of those affected worldwide are *** China,the rare disease patients are over 10 million,and70 percent of the patients are children(Song et al.,2012;Liu et al.,2010).

关键词： deterioration childhood burden children featuring promise birth mortality pediatric distinguished

Effect of warm rolling process on microstructures and tensile properties of 10 Mn steel

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2020年第12期47卷 131-141页

作者： Bin Hu xin Tu Haiwen luo xinping Mao School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China

The influence of warm rolling processes on the microstructures and tensile properties of 100 Mn steel was *** appeared to increase with the rolling temperature but strengthening mechanisms *** increase of warm rolling temperature from 250℃ to 600℃ leads to enhanced recrystallization in martensite during the intercritical annealing(IA) at 620℃ for 5 *** a result,both ultimate tensile strength(UTS) and total elongation(TE) ***,the size of relatively coarse recrystallized austenite grains and the resultant yield strength(YS) remain almost constant in this temperature *** further increase of rolling temperature to 700-800℃ causes a considerable amount of pearlite to be formed during the IA,and then martensite is formed after the IA,resulting in dramatical increases in both YS and UTS but at the great loss of *** warm rolling at 600℃ with 63% thickness reduction can produce the steel with the best mechanical combination of 1.2 GPa UTS and 35% TE,due to the formation of many ultrafine austenite grains and strain-induced cementite *** demonstrates that the mechanical combination of non-V-alloyed medium Mn steel can be improved to an equivalent level of 0.7% V alloyed 10 Mn steel just via the economic strain-induced cementite precipitation.

关键词： Warm rolling Cementite precipitation Austenite stability Mechanical properties

Source Quantitative Identification by Reference-Based Cubic Blind Deconvolution Algorithm

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2023年第4期36卷 180-195页

作者： xin luo Zhousuo Zhang Teng Gong Yongjie Li State Key Laboratory for Manufacturing Systems Engineering Xi’an Jiaotong UniversityXi’an 710049China

The semi-blind deconvolution algorithm improves the separation accuracy by introducing reference ***,the separation performance depends largely on the construction of reference *** improve the robustness of the semi-blind deconvolution algorithm to the reference signals and the convergence speed,the reference-based cubic blind deconvolution algorithm is proposed in this *** proposed algorithm can be combined with the contribution evaluation to provide trustworthy guidance for suppressing satellite *** normalized reference-based cubic contrast function is proposed and the validity of the new contrast function is theoretically *** deriving the optimal step size of gradient iteration under the new contrast function,we propose an efficient adaptive step optimization ***,the contribution evaluation method based on vector projection is presented to implement the source contribution *** simulation analysis is carried out to validate the availability and superiority of this *** tests given by the simulated satellite experiment and satellite ground experiment also confirm the *** signals of control moment gyroscope and flywheel were extracted,respectively,and the contribution evaluation of vibration sources to the sensitive load area was *** research proposes a more accurate and robust algorithm for the source separation and provides an effective tool for the quantitative identification of the mechanical vibration sources.

关键词： Quantitative identification Reference-based cubic contrast function Semi-blind deconvolution Satellite micro-vibration Adaptive step size