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Acta Mechanica Solida Sinica 2016年第6期29卷 577-595页

作者： Nian Yang Luyun Chen Hong Yi Yong Liu State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Ship scientific research center of China Shanghai Branch

Most existing studies on the vibration analysis of cylindrical shells with structural stress are limited to uniform stress distribution. However, non-uniform stress distributions are encountered in many engineering applications. In this study, a unified solution for the vibration analysis of cylindrical shells with a general stress distribution is presented using the Fliigge shell theory and modal orthogonality simplification. The obtained analytical solution can be applied to a structure with arbitrary distributed stress, thus it has a wider range of applications than previous methods. The accuracy and advantage of the proposed method are validated by comparing with the finite element method results.

关键词： free vibration cylindrical shells structural stress

Study on Collision Characters for SPAR Platform

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China Ocean Engineering 2008年第1期22卷 131-139页

作者：胡志强崔维成 State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University China Ship scientific research center

This paper presents the research on the external mechanism of collision characters for a SPAR platform. The collision characters of SPAR platform have not attracted so much attention as that of ships in the past, because short of this kind of collision accidents reported. But with the increasing number of SPAR platforms in the world, the possibility of such kind of accident also increases. Therefore, it is necessary to master the character of SPAR collision. Model test technique is employed to study the external mechanism. The collision scenario is a ship colliding with a SPAR platform moored in the site with 1500 meters water depth. The striking ship hits the SPAR platform on the hard tank near water surface in its longitudinal direction. The specifics of the SPAR＇s motions and the tension forces of the mooring lines are collected to summarize the hydrodynamic characters in the collision scenario. It is found that the maximal displacements and the maximal pitch angles of the SPAR platform, and the maximal tension forces of mooring lines are all linearly proportional to the initial velocity of the striking ship basically. Mooring lines play elastic roles in the collision course.

关键词： collision character external mechanism SPAR platform model test

Reynolds and Mass-Damping Effect on Prediction of the Peak Amplitude of A Freely Vibrating Cylinder

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China Ocean Engineering 2008年第1期22卷 21-30页

作者：黄智勇崔维成刘应中黄小平 State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University China Ship scientific research center

The Reynolds effect and mass-damping effect on the peak amplitude of a freely vibrating cylinder is studied by using forced oscillating data from Gopalkrishnan＇ s research in 1993, in which all experimental cases were carried out at a fixed Reynolds and the tested cylinder was recognized as a body that had no mass and damping. However, the Reynolds and roass-damping are the very important parameters for the peak amplitude of a freely vibrating cylinder. In the present study, a function F is introduced to connect the forced oscillation and free vibration. Firstly the peak amplitude AG^＊ can be obtained from the function F using forced oscillation data of Gopalkrishnan＇ s experimental at Re = 10^4, and then the Reynolds effect is taken into account in the function f（Re）, while the mass-damping effect is considered in the function K（ α ）, where a is the mass-damping ratio. So the peak amplitude of a freely vibrating cylinder can be predicted by the expression： A ^＊ = K（ α ）f（ Re ）AG^＊ . It is found that the peak transverse amplitudes predicted by the above equation agree very well with many recent experimental data under both high and low Reynolds conditions while roass-damping varies. Furthermore, it is seen that the Reynolds number does have a great effect on the peak amplitude of a freely vibrating cylinder. The present idea in this paper can be applied as an update in the empirical models that also use forced oscillation data to predict the vortex induced vibration （VIV） response of a long riser in the frequency domain.

关键词： Reynolds mass-damping vortex induced vibration forced oscillation free vibration

Apparent diffusion coefficient by diffusion-weighted magnetic resonance imaging as a sole biomarker for staging and prognosis of gastric cancer

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Chinese Journal of Cancer research 2017年第2期29卷 118-126页

作者： Francesco Giganti Alessandro Ambrosi Damiano Chiari Elena Orsenigo Antonio Esposito Elena Mazza Luca Albarello Carlo Staudacher Alessandro Del Maschio Francesco De Cobelli Department of Radiology and experimental Imaging center San Raffaele Scientific Institute Milan Italy Vita-Salute San Raffaele University Milan Italy Department of Surgery San Raffaele Scientific Institute Milan Italy Department of Oncology San Raffaele Scientific Institute Milan Italy Pathology Unit San Raffaele Scientific Institute Milan Italy

Objective： To investigate the role of apparent diffusion coefficient （ADC） from diffusion-weighted magnetic resonance imaging （DW-MRI） when applied to the 7th TNM classification in the staging and prognosis of gastric cancer （GC）. Methods： Between October 2009 and May 2014, a total of 89 patients with non-metastatic, biopsy proven GC underwent 1.5T DW-MRI, and then treated with radical surgery. Tumor ADC was measured retrospectively and compared with final histology following the 7th TNM staging （local invasion, nodal involvement and according to the different groups -- stage Ⅰ, Ⅱ and Ⅲ）. Kaplan-Meier curves were also generated. The follow-up period is updated to May 2016. Results： Median follow-up period was 33 months and 45/89 （51%） deaths from GC were observed. ADC was significantly different both for local invasion and nodal involvement （P〈0.001）. Considering final histology as the reference standard, a preoperative ADC cut-offof 1.80×10-3 mm^2/s could distinguish between stages I and Ⅱ and an ADC value of ≤1.36-10-3 mm^2/s was associated with stage Ⅲ（P〈0.001）. Kaplan-Meier curves demonstrated that the survival rates for the three prognostic groups were significantly different according to final histology and ADC cut-offs （P〈0.001）. Conclusions： ADC is different according to local invasion, nodal involvement and the 7th TNM stage groups for GC, representing a potential, additional prognostic biomarker. The addition of DW-MRI could aid in the staging and risk stratification of GC.

关键词： Apparent diffusion coefficient diffusion-weighted magnetic resonance imaging gastric cancer prognosis TNM staging

experimental study of shear properties of 3D woven composite using digital image correlation and acoustic emission

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Acta Mechanica Sinica 2020年第2期36卷 448-459页

作者： E.M.Strungar A.S.Yankin E.M.Zubova A.V.Babushkin A.N.Dushko center of experimental Mechanics Perm National Research Polytechnic University614990 PermRussian Federation Engineering center PJSC“UEC-Saturn” 152903 RybinskRussian Federation

This work is dedicated to the experimental study of the shear properties of three-dimensional reinforced composites taking into account their structural features,in Iosipescu *** strains have been determined using Vic-3D non-contact three-dimensional digital optical *** evolution of inhomogeneous strain fields on the surface of composite specimens of the structure under study has been *** variants of strain averaging in the specimen working area have been analyzed using Vic-3D ***-6 acoustic emission system has been used to assess the structural integrity of composite materials under loading.

关键词： Carbon-fiber composite 3D reinforced composite Digital image correlation Acoustic emission technique Iosipescu test

Investigations on vortex structures for undulating fin propulsion using phase-locked digital particle image velocimetry

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Journal of Hydrodynamics 2021年第3期33卷 572-582页

作者： Ya-qiang Bai Jun Zhang Shu-cheng Zhai Guo-ping Zhang China Ship scientific research center Wuxi214082China National Key Laboratory on Ship Vibration and Noise Wuxi214082China

The Gymnarchus niloticus fish can swim in surging and heaving directions only with a long undulating ribbon fin while keeping its body along almost straight *** features substantially inspire the design of underwater vessels with high maneuverability and station keeping performance,which is characterized by peculiar vortex structures induced by undulating fin *** reveal the propulsion mechanism under the evolution of these complex vortex structures,the variation of velocity field with the undulating fin’s wave phase on cross section and mid-sagittal plane at wave amplitude of 85°is investigated by phase-locked digital particle image velocimetry(DPIV).Through experimental flow field images,two typical vortex structures are clearly identified,i.e.,streamwise vortex and crescent vortex,which is further explained by supplemental numerical simulations using large eddy *** characteristic and its evolution on cross sections and mid-sagittal planes is investigated,and its relationship with thrust,heave force is also *** is found that the two kinds of vortexes induce the main hydrodynamic forces in two directions synchronously,which brings the undulating fin propulsion an extra-ordinal *** research will be useful for understanding the potential mechanism of this novel propulsion and is of great application prospect in designing more maneuverable underwater vehicles.

关键词： Undulating fin propulsion vortex structure phase-locked digital particle image velocimetry(DPIV) hydrodynamic mechanism

Investigation on strong nonlinear interactions between underwater explosion and water surface based on compressible multiphase flow with phase transition

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Journal of Hydrodynamics 2023年第2期35卷 351-364页

作者： Jun Yu Hai-kun Wang Zhen-xin Sheng Yi Hao China Ship scientific research center Wuxi214082China Taihu Laboratory of Deep-sea Technological Science Wuxi214082China

The strong nonlinear interactions between underwater explosion and water surface were numerically investigated using a phase transition model based on a four-equation system,which can deal with the complex deformable interface among different phases,including water,air,explosion bubble,and *** numerical method is verified by comparing the numerical results with experimental results,and good agreements are *** study considers an ideal sine wave for simulating the shape of water *** examples of different detonation depths of charge are *** each example,the first case is the basic simulation without surface wave,and the other three cases are the simulations with sine waves of different *** characteristics of the interactions,such as shock wave propagation,explosion bubble expansion,and the generation,development,and collapse of cavitation,are observed in the numerical *** capturing the detailed density and pressure contours during the interaction process,we can better understand the underlying mechanisms of the explosion bubble,cavitation,and surface *** numerical results demonstrate that geometric nonlinearity impacts cavitation evolution and the explosion bubble movement ***,the secondary cavitation phenomenon has been found in the cases without surface wave,and its fundamental physical mechanism is presented in *** present results can expand the existing database of multiphase flow in the underwater explosion and provide an insight into the strong nonlinear interaction between the underwater explosion and water surface.

关键词： Underwater explosion compressible multiphase flow phase transition model cavitation water surface

Influence of Lanthanum on Synthesizing of SiC Nanometer Powder

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Journal of Rare Earths 2007年第S2期25卷 98-103页

作者：张宁龙海波王柳燕才庆魁 scientific Technology research center Shenyang University

Low cost silicon carbon nanometer powder was synthesized by carbothermal reduction method with nanometer SiO2 and carbon as raw material. Its synthesis thermodynamics were discussed. The influence of La on TG-DSC curve was also analyzed. It indicated that the synthesis process of SiC powder had two steps. In the first step two medial productions of SiOg and COg formed, and in the second step, β-SiC was finally synthesized. After 0.3% La added, at the first step, the initiatory forming temperature of producing SiO(g) and CO(g) declined from 1351.4 to 1250.9 ℃, and the thermal activation energy decreased from 223.6 to 34.7 J·g-1; at the second step the initiatory forming temperature of synthesizing β-SiC powder declined from 1526.5 to 1357.8 ℃, and the thermal activation energy decreased from 693.7 to 295.7 J·g-1. Without La added, the best synthesis technology for β-SiC powder was 1550 ℃ for 120 min, average powder diameter was bigger about 150 nm. With La added, the best synthesis technology was 1500 ℃ for 120 min, average powder diameter was about 100 nm.

关键词： lanthanum SiC synthesis temperature low cost nanometer powder rare earths

On the properties of the Rational Function Spectrum describing waves near islands and reefs in South China Sea

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Journal of Hydrodynamics 2021年第5期33卷 879-888页

作者： Yi-geng Wang Zhi Zong Li Zhou Xiao-long Liu Xue-kang Gu School of Naval Architecture Dalian University of TechnologyDalian 116024China China Ship scientific research center Wuxi 214082China

On-site measurements show that water waves near islands and reefs in South China Sea exhibit different properties of wave energy distributions with regard to wave frequencies,among which the most prominent factor is the interplay of swells arising from the West Pacific Ocean and the local wind *** also show that the breaking waves continuously appear,containing more energy in high frequency components,and the nonlinear characteristics of the waves are important in adjusting the energy *** properties may explain the large discrepancies between the well-accepted wave spectra(for example the P-M spectrum,Neumann spectrum,ITTC spectrum etc.)and the measured wave spectra near islands and reefs in South China ***,a new Rational Function Spectrum is proposed in this paper to describe waves near islands and reefs which turns out to show satisfactory *** well captures wave power distributions in the form of single and double peaks,at low-and high-frequency regions,as well as nonlinear scale power *** on the investigation of the measured data near an island in South China Sea,the relation between the parameters used in the Rational Function Spectrum and the statistical parameters of water waves(significant wave height and wave period)is *** is noted that the wave properties at low-and high-frequencies are controlled by the local wind velocities at the wave growth stage,but remain constant at the wave decay *** parameter peak frequency is only dependent on the wave period corresponding to the maximum wave *** parameter spectral peak is determined from the wave height and the wave *** relations help to clarify the physical meanings of the parameters used in the Rational Function Spectrum,and thus provide an alternative spectral form to describe random waves near islands and reefs.

关键词： Rational Function Spectrum double peak near islands and reefs swell nonlinear

The characteristics of waves around an entrance of a lagoon in South China Sea

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Journal of Hydrodynamics 2021年第5期33卷 889-900页

作者： Zhi-wen Cai Chun-rong He Xiao-long Liu Wen-wei Chen Ze Sun Jun Ding China Ship scientific research center Wuxi 214082China Southern Marine Science and Engineering Guangdong Laboratory(Zhanjiang) 524000China

The characteristics of the waves around a lagoon entrance in South China Sea were observed during the past one and half years based on the wave *** measured results show that the monsoon plays an important *** summer,waves mostly come from the southeast,among which the wave components of non-dimensional periods larger than 0.2 are fetch-trapped *** winter the waves may be divided into two groups,the fetch-trapped waves and the waves from the open *** skewness of the directional distribution functions is within+8 around *** power relationship between the direction spread and kurtosis is also ***,it is found that the waves with the significant wave heights greater than 1.5 m are caused by typhoons or cold *** frequency components of wave energy driven by cold air appear in the high frequency range at first,and change to the lower frequency range *** waves driven by typhoon mostly come from the open sea.

关键词： Reef lagoon cold air typhoon waves South China Sea Introduction