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Complex dynamical behaviors of compact solitary waves in the perturbed mKdV equation

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Chinese Physics B 2014年第8期23卷 205-210页

作者：殷久利邢倩倩田立新 Nonlinear Scientific research center Faculty of ScienceJiangsu University

In this paper, we give a detailed discussion about the dynamical behaviors of compact solitary waves subjected to the periodic perturbation. By using the phase portrait theory, we find one of the nonsmooth solitary waves of the mKdV equation, namely, a compact solitary wave, to be a weak solution, which can be proved. It is shown that the compact solitary wave easily turns chaotic from the Melnikov theory. We focus on the sufficient conditions by keeping the system stable through selecting a suitable controller. Furthermore, we discuss the chaotic threshold for a perturbed system. Numerical simulations including chaotic thresholds, bifurcation diagrams, the maximum Lyapunov exponents, and phase portraits demonstrate that there exists a special frequency which has a great influence on our system; with the increase of the controller strength, chaos disappears in the perturbed system. But if the controller strength is sufficiently large, the solitary wave vibrates violently.

关键词： Melnikov method compacted solitary waves control threshold

Mechanical properties of the A356 aluminum alloy modified with La/Ce

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Journal of Rare Earths 2013年第8期31卷 811-816页

作者： E. Aguirre-De la Torre R. Pérez-Bustamante J. Camarillo-Cisneros C.D. Gómez-Esparza H.M. Medrano-Prieto R. Martínez-Sánchez Advanced Materials research center (CIMAV) National Laboratory of Nanotechnology

The research of rare earths for the synthesis of materials with improved mechanical performance is of great interest when they are considered for potential applications in the automotive industry. In this regard, the effect on the mechanical properties and microstmcture of the automotive A356 aluminum alloy reinforced with 0.2 （wt.%） AI-6Ce-3La （ACL） was investigated. The ACL was added to the melted A356 alloy in the as-received condition and processed by mechanical milling. In the second route, the effect of the ACL processed by mechanical milling and powder metallurgy techniques was investigated, and compared with the results ob- tained from the A356 alloy strengthened with ACL in the as-received condition. Microstmctural properties were evaluated by means of X-ray diffraction in order to observe the solubility of Ce/La in the A1 matrix. In addition, electron microscopy was employed in or- der to investigate the effect of milling time on the size and morphology of La/Ce phase under milling process. Mechanical properties of the A356 alloy modified with ACL were measured by hardness and tensile test. For comparison unmodified specimens of the A356 were characterized according to the previous procedure. The microstructural and mechanical characterization was carried out in specimens alter solution and artificial aging. Observations in scanning electron microscopy indicated a homogeneous dispersion of La/Ce phases by using both routes; however, mechanical results, in the modified A356 alloy with the ACL in the as-received condi- tion, showed an improvement in the mechanical performance of the A356 alloy over that reinforced with the ACL mechanically milled.

关键词： A356 rare earths mechanical milling mechanical properties

Theory and applications of coupled fluid-structure interactions of ships in waves and ocean acoustic environment

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Journal of Hydrodynamics 2016年第6期28卷 923-936页

作者：吴有生邹明松田超司马灿祁立波丁军李志伟陆晔 China Ship Scientific research center Wuxi 214082 China

Wave induced motions and structural distortions, and machinery or propeller excited vibrations and acoustic radiations of a ship are two kinds of important fluid-structure interaction problems. The branch of ship science that describes the coupled wave induced dynamic behavior of fluid-structure interaction system is referred to as hydroelasticity. During the past three decades the development of three-dimensional hydroelasticity theories and applications gained great progress. Recently the 3-D hydroelasticity theory was further extended to account for the fluid compressibility and the effect of the ocean acoustic environment with finite water depth. A three-dimensional sono-elasticity theory was then produced. In this paper, the 3-D hydroelasticity theory and the 3-D sono-elasticity theory of ships are briefly described. To illustrate the applicability and feasibility of these theories and the corre- sponding numerical approaches, several examples are presented including the predictions of wave loads, rigid-body and flexible- body responses, springing and fatigue behaviors, machinery or propeller excited coupled structural vibrations and acoustic radiations, as well as design optimizations for improving safety and acoustic behaviors of ships.

关键词： hydroelasticity sono-elasticity wave load structural strength springing vibration acoustic radiation

Real-time retrieval of submicron aerosol size distributions from multi-wavelength spectral extinction measurements

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Instrumentation 2016年第1期3卷 50-60页

作者： CHEN Jiawei YANG Mu FENG Haibao NI Qijun China Ship Scientific research center China great Wall Industry Corporation

The real-time retrieval of submicron aerosol size distributions is of major interest for applications. Based on the Mie theory,the spectral extinction method offers a simple measurement principle and a convenient optical arrangement. In contrast to the relative simplicity of the experimental measurement the retrieval of the particles size distribution and particle concentration from the spectral extinction method is difficult. Mie scattering Equation is a Fredholm Integral Equation of the First Kind. This paper develops a hybrid iterative model-dependent algorithm for on-line particle sizing from extinction spectra which is both computationally efficient and accurate. Applying the refined Mie diagnostic iterative procedures within some candidate solutions can identify the unique result accurately and rapidly enough for real time measurement. With the addition of added Gaussian noise,an average tolerance up to 5% of noise level is kept for particle size from submicron to micrometer under moderate polydispersity.

关键词： hybrid iterative algorithm on-line particle size extinction spectra

Work Productivity and Activity Impairment in Breast Cancer Patients Treated with Capecitabine

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Journal of Cancer Therapy 2013年第7期4卷 1224-1227页

作者： Marco Vacante Giulia Malaguarnera Manuela Pennisi Giuseppe Grosso Salvatore Salomone Filippo Drago Erdogan Ozyalcin Vito Catania Alfredo Consoli Mariano Malaguarnera Department of General Surgery University of Catania Catania Italy Department of Neurosciences University of Catania Catania Italy International PhD Programme in Neuropharmacology University of Catania Catania Italy research center “the great senescence” Cannizzaro Hospital University of Catania Catania Italy

Background: Although the majority of breast cancer patients are able to work, lower work ability and reduced job retention have been reported. The aim of the present study was to evaluate the effect of chemotherapy with capecitabine in patients with breast cancer on work productivity and daily activity. Methods: 34 patients with metastatic breast cancer were enrolled for our study. Capecitabine was given twice daily at a cumulative dose of 2500 mg/m2 on days 1 - 14 and repeated on day 22. Work productivity was determined using the WPAI questionnaire. Results: We observed an increase in absenteeism, presenteeism, work productivity loss and daily activity impairment after 1 cycle and 6 cycles of therapy, but we could not find statistically different significances. Conclusions: This study provides some data indicating an association between problems in breast cancer and work. Our results confirm that capecitabine may improve quality of life of patients with metastatic breast cancer.

关键词： Breast Cancer Capecitabine Work Productivity Absenteeism Presenteeism

A single-cell encapsulation method based on a microfluidic multi-step droplet splitting system

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Chinese Chemical Letters 2015年第12期26卷 1450-1454页

作者： Chun-Guang Yang Ru-Yi Pan Zhang-Run Xu research center for Analytical Sciences Northeastern University

Single cell analysis is of great significance to understand the physiological activity of *** droplet is an ideal analytical platform for single-cell analysis. We developed a microfluidic droplet splitting system integrated with a flow-focusing structure and multi-step splitting structures to form 8-line droplets and encapsulate single cells in the droplets. Droplet generation frequency reached1021 Hz with the aqueous phase flow rate of 1 m L/min and the oil phase flow rate of 15 mL /min. Relative standard deviation of the droplet size was less than 5% in a single channel, while less than 6% in all the8 channels. The system was used for encapsulating human whole blood cells. A single-cell encapsulation efficiency of 31% was obtained with the blood cell concentration of 2.5 ？ 104cells/mL, and the multicellular droplet percentage was only 1.3%. The multi-step droplet splitting system for single cell encapsulation featured simple structure and high throughput.

关键词： encapsulation droplet splitting throughput disperse suspension deviation physiological focusing mixing

Improving the real-time probabilistic channel flood forecasting by incorporating the uncertainty of inflow using the particle filter

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Journal of Hydrodynamics 2018年第5期30卷 828-840页

作者： Xing-ya Xu Xuesong Zhang Hong-wei Fang Rui-xun Lai Yue-feng Zhang Lei Huang Xiao-bo Liu Changjiang Institute of Survey PlanningDesign and ResearchWuhan 430010China State Key Laboratory of Hydroscience and Engineering Department of Hydraulic EngineeringTsinghua UniversityBeijing 100084China Joint Global Change research Institute Pacific Northwest National LaboratoryCollege ParkMDUSA great Lakes Bioenergy research center Michigan State UniversityEast LansingMichiganUSA Yellow River Institute of Hydraulic research Zhengzhou 450003China Development research center of the Ministry of Water Resources of People＇s Republic of China Beo＇ing 100038China Department of Water Environment China Institute of Water Resources and Hydropower ResearchBeo＇ing 100038China

An accurate and reliable real-time flood forecast is crucial for mitigating flood disasters. The errors associated with the inflow boundary forcing data are considered as an important source of uncertainties in hydraulic model. In this paper, a real-time probabilistic channel flood forecasting model is developed with a novel function to incorporate the uncertainty of the forcing inflow. This new approach couples a hydraulic model with the particle filter（PF） data assimilation algorithm, a sequential Bayesian Monte Carlo method. The stage observations at hydrological stations are assimilated at each time step to update the model states in order to improve the next time step＇s forecasting. This new approach is tested against a real flood event occurred in the upper Yangtze River. As compared with the open loop simulations, the evaluations of model performance with several deterministic and probabilistic metrics indicate that the accuracy of the ensemble mean prediction and the reliability of the uncertainty quantification are improved pronouncedly as a result of the PF assimilation. Further assessment of the prediction results at different lead times shows that the improvement of model performance deteriorates with the increase of the lead time due to the gradual diminishing of the updating effect for the initial conditions. Based on the analyses of the number of particles and the assimilation frequency, we find that the optimal number of particles can be determined by balancing the model performance and the computation cost, while a high assimilation frequency is preferred to incorporate the emerging observations to update the model states to match the real conditions.

关键词： Channel flood forecasting probabilistic forecast particle filter hydraulic model data assimilation inflow uncertainty

Cohesion variation during instability evolution of disaster medium in mud inrush of mountain tunnel

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Journal of Mountain Science 2019年第11期16卷 2519-2531页

作者： YANG Teng ZHANG Qing-song ZHANG Xiao LI Xiang-hui ZHANG Jia-qi SUN Yu-xue LI Zhuang Geotechnical & Structural Engineering research center Shandong University

Mud inrush in mountain tunnel is an independent geological hazard type different from water inrush,landslide and debris *** intrinsic factor of mud inrush is the instability failure of disaster *** essence is that when the cohesion decreases gradually with the increase of void ratio to the point where the movement of soil particles cannot be restricted,soil particles and groundwater form slurry and gush ***,accurate calculation of cohesion with variable void ratios is crucial for analyzing the reliability of disaster *** this study,the disaster medium was regarded as graded soil and a structural model was established wherein soil particles were simplified as cubes and the inter-particle pores were represented by the clearance between *** the basis of the structure model of disaster medium,a function between the soil particle distance and void ratio was *** is equivalent to the resultant force between soil particles per unit area;thus,a cohesion function was derived in which the void ratio is the main *** function considers the influence of gradation characteristics on cohesion variation and is generally applicable to various types of disaster medium.A series of direct shear tests were carried out to determine the cohesion variation for different types of disaster medium with variable void *** comparing the variation of cohesion obtained through direct shear tests with those deduced by the proposed cohesion function,we verified the validity and general applicability of the cohesion *** is of great significance because the cohesion function can accurately predict the variation of cohesion by using the void ratio,and effectively evaluate the possibility of mud inrush according to the initial mechanical properties of disaster medium.

关键词： Cohesion Disaster medium Graded soil Structure model Void ratio Shear test

Effect of heterogeneity on mechanical and acoustic emission characteristics of rock specimen

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Journal of Central South University 2010年第5期17卷 1119-1124页

作者：李术才李国莹 Geotechnical and Structural Engineering research center Shandong University

The influence of heterogeneity on mechanical and acoustic emission characteristics of rock specimen under uniaxial compress was studied with numerical simulation *** distribution function was adopted to describe the mesoscopic heterogeneity of *** failure process of heterogeneous rock specimen under uniaxial loading was simulated using FLAC 3D *** schemes were adopted to investigate the influence of *** results demonstrate that as the homogeneity increases,the peak strength and brittleness of rocks increase,and the macro elastic modulus improves as *** has great influence on macro elastic modulus and strength when the homogeneity coefficient is less than *** volume expansion is not so obvious when the homogeneity *** the homogeneity coefficient increases the acoustic emissions modes change from swarm shock to main *** the homogeneity coefficient is high,the cumulative acoustic emission events-axial strain curve is gentle before the rock *** numerical results agree with the previously numerical results and earlier experimental measurements.

关键词： heterogeneity acoustic emission strain softening numerical simulation uniaxial compression elastic modulus