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Nonlinear Numerical Analysis of Vortex-Induced Vibration of A Three-Dimensional Deepwater Steep Wave Riser with Large Deformation Features

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China Ocean Engineering 2022年第4期36卷 601-613页

作者： CHENG Yong SONG Fu-kai li ming-xin School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China

The cross-flow(CF)vortex-induced vibration(VIV)of a deepwater steep wave riser(SWR)subjected to uniform or shear flow loads is investigated *** model is based on a three-dimensional(3D)nonlinear elastic rod theory coupled with a wake oscillator *** this numerical simulation,the nonlinear motion equations of the riser with large deformation features are established in a global coordinate system to avoid the transformation between global and local coordinate systems,and are discretized with the time-domain finite element method(FEM).A wakeoscillator model is employed to study the vortex shedding,and the lift force generated by the wake flow is described in a van der Pol equation.A Newmark-βiterative scheme is used to solve their coupling equation for the VIV response of the *** developed model is validated against the existing experimental results for the VIV response of the top-tension riser(TTR).Then,the numerical simulations are executed to determine VIV characteristics of the *** effects of both flow velocity and the spanwise length of the flow field on the drag coefficient in the inline(IL)direction and the lift coefficient in the CF direction are investigated *** results indicate that compared with TTR,the low frequency and multi-modal vibration are the main components of the SWR due to the large deformation and flexible *** shear flow,the multi-frequency resonance dominates the VIV response of the SWR,especially at the hang-off segment.

关键词： steep wave riser vortex-induced vibration time domain simulation nonlinear finite element wake oscillator

Numerical Modelling of Wash Waves Generated by Ships Moving over An Uneven Bottom

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China Ocean Engineering 2023年第1期37卷 145-153页

作者： li ming-xin YUAN Zhi-ming BAI Xu li Yong-zheng CHENG Yong TAO Long-bin School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China Department of Naval Architecture Ocean and Marine EngineeringUniversity of StrathclydeGlasgow G11XQUK

Unsteady wash waves generated by a ship with constant speed moving across an uneven bottom topography are investigated by numerical simulations based on a Mixed Euler–Lagrange(MEL) method. The transition is accomplished by the ship traveling from the depth h1 into the depth h2 via a step bottom. A small tsunami would be created after this transition. However, the unsteady wave-making resistance induced by this new phenomenon has not been well documented by literature. Therefore, the main purpose of the present study is to quantify the effects of an uneven bottom on the unsteady wash waves and wave-making resistance acting on the ship. An upwind differential scheme is commonly used in the Euler method to deal with the convection terms under free-surface condition to prevent waves in the upstream. Evidently, it cannot be applied to the present problem due to upstream waves generated by the ship would be dampened by the upwind scheme. The central differential scheme provides more accurate results,but it is not unconditionally stable. An MEL method is therefore employed to investigate the upstream wave generated by the ship moving over the uneven bottom. Simulation results show that the hydrodynamic interaction between the ship and the uneven bottom could initiate an upstream tsunami, as well as unsteady wave-making resistance on *** unsteady wave-making resistance oscillates periodically, and the amplitude and period of the oscillations are highly dependent on speed and water depth.

关键词： uneven bottom upstream wave unsteady wave resistance numerical simulation periodic oscillation

Failure Statistics Analysis Based on Bayesian Theory: A Study of FPSO Internal Turret Leakage

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China Ocean Engineering 2019年第1期33卷 14-25页

作者： KANG Ji-chuan WANG Lang li ming-xin SUN li-ping JIN Peng College of Shipbuilding Engineering Harbin Engineering University Center for Marine Technology and Engineering University of Lisbon Yantai CIMC Raffles Offshore limited

The load and corrosion caused by the harsh marine environment lead to the severe degradation of offshore equipment and to their compromised security and reliability. In the quantitative risk analysis, the failure models are difficult to establish through traditional statistical methods. Hence, the calculation of the occurrence probability of small sample events is often met with great uncertainty. In this study, the Bayesian statistical method is implemented to analyze the oil and gas leakages of FPSO internal turret, which is a typical small sample risk but could lead to severe *** to the corresponding failure mechanism, two Bayesian statistical models using the Weibull distribution and logarithmic normal distribution as the population distribution are established, and the posterior distribution of the corresponding parameters is calculated. The optimal Bayesian statistical model is determined according to the Bayesian information criterion and Akaike criterion. On the basis of the determined optimal model, the corresponding reliability index is solved to provide basic data for the subsequent risk assessments of FPSO systems.

关键词： risk analysis Bayesian theory FPSO internal turret system Markov chain Monte Carlo

0.05%环孢素滴眼液对糖尿病视网膜病变患者玻璃体切割术后泪膜稳定性和眼表功能的影响

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川北医学院学报 2024年第10期39卷 1390-1394页

作者：高桂芬王贺徐为海李明新徐州医科大学附属医院眼科江苏徐州221000 滨海县人民医院眼科江苏盐城224500

目的:探讨0.05%环孢素滴眼液对糖尿病视网膜病变(DR)玻璃体切割术后患者干眼症状、体征和眼表功能的影响。方法:选取100例行玻璃体切割术的DR患者为研究对象,按照干预方式不同分为实验组(n=50,50眼,右眼)和对照组(n=50,50眼,右眼)。实... 详细信息

目的:探讨0.05%环孢素滴眼液对糖尿病视网膜病变(DR)玻璃体切割术后患者干眼症状、体征和眼表功能的影响。方法:选取100例行玻璃体切割术的DR患者为研究对象,按照干预方式不同分为实验组(n=50,50眼,右眼)和对照组(n=50,50眼,右眼)。实验组使用0.05%环孢素滴眼液治疗;对照组使用0.3%玻璃酸钠滴眼液治疗。治疗前和治疗后1、4、12周,评估患者眼表疾病指数(OSDI)、非侵入性首次泪膜破裂时间(NIBUTf)、非侵入性平均泪膜破裂时间(NIBUTav)、非侵入式泪河高度(NITMH)、睑板腺缺失度评分、泪膜脂质层厚度评分、眼红分析、眼表染色评分(OSS)和最佳矫正视力(BCVA),并记录治疗期间发生的不良反应。结果:治疗后各时间点,实验组OSDI评分均低于对照组(P0.05);实验组与对照组均未发生严重不良反应。结论:0.05%环孢素滴眼液在DR患者玻璃体切割术后能够有效改善干眼症状,提高泪膜稳定性,改善眼表功能参数,且安全性较高。

关键词： 0.05%环孢素滴眼液糖尿病视网膜病变玻璃体切割术泪膜稳定性

广东省2019—2023年耐万古霉素屎肠球菌检出率升高的时空变迀研究

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中国感染控制杂志 2024年第4期23卷 397-402页

作者：卓楚越林烨欣王译靖陈嘉康郭颖异姚丽康杨旭李嘉慧陈杨进何南豪赵雅婷李明欣肖书念卓超广州医科大学附属第一医院(广东省耐药菌监测和质量控制中心)广州呼吸健康研究院广东广州510030 广州医科大学呼吸疾病全国重点实验室广东广州510030

目的分析近年广东省耐万古霉素屎肠球菌(VR-Efm)临床分离株的时空分布,探寻VR-Efm检出率上升的原因。方法回顾性分析2019—2023年广东省4个区域(珠三角、粤东、粤西、粤北)的38所医疗机构上报至广东省细菌耐药监测系统中VR-Efm检出情况... 详细信息

目的分析近年广东省耐万古霉素屎肠球菌(VR-Efm)临床分离株的时空分布,探寻VR-Efm检出率上升的原因。方法回顾性分析2019—2023年广东省4个区域(珠三角、粤东、粤西、粤北)的38所医疗机构上报至广东省细菌耐药监测系统中VR-Efm检出情况、患者人口学特征及科室和标本分布等资料,同步分析世界卫生组织重点关注的ESKAPE中其他5种细菌的检出情况。结果广东省VR-Efm检出率从2019年1.4%(63/4543)上升至2023年21.3%(1351/6345),呈明显上升趋势,2023年44.7%(17所)的医疗机构VR-Efm检出率>20%;广东省4个区域VR-Efm检出率普遍上升,以珠三角地区为中心向周围辐射增长。ESKAPE整体由2019年10.1%升至2023年10.8%,其余5种病原体中,耐碳青霉烯类肺炎克雷伯菌检出率从2019年8.0%上升至2023年15.0%,耐碳青霉烯类鲍曼不动杆菌、耐甲氧西林金黄色葡萄球菌、耐碳青霉烯类铜绿假单胞菌和耐碳青霉烯类肠杆菌属检出率分别从2019年的61.6%、34.4%、21.2%、7.9%下降至2023年的58.2%、31.9%、21.0%、7.6%,皆有不同程度下降。ICU VR-Efm检出率(12.2%)高于门急诊(9.4%)、内科(9.2%)和外科(7.0%)等非ICU科室(均P9.4%,P<0.05)。结论近5年广东省VR-Efm检出率明显上升,可能与社区和医院获得的优势克隆传播有关。有条件的医疗机构应对入院患者开展VR-Efm的筛查,并对检出VR-Efm的患者采取有效防控措施,以遏制VR-Efm检出率在该区域的上升。

关键词：耐万古霉素屎肠球菌屎肠球菌耐药细菌耐药监测耐药性变迁

Comparisons of Three Recurrent Selection Methods in the Improvement of Maize Populations

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Agricultural Sciences in China 2007年第6期6卷 657-664页

作者： PENG Ze-bin li ming-shun liU xin-zhi li Jun-qiang Institute of Crop Sciences Chinese Academy of Agricultural Sciences Beijing 100081 P.R.China

The maize population Csyn 4 was improved for three cycles with three recurrent selection methods MS1, MS1-HS, and MHSRRS in northern China. A total of 40 NC Ⅱ testcrosses were made by four testers with Csyn 4 and 10 improved populations, which were evaluated in four environments in the cropping season of 2005. Analysis of variance indicated a significant progress （P〈 0.05） in yield and other chief agronomic traits in the improved populations and testcrosses, demonstrating that the three recurrent selection methods were effective for increasing grain yield of testcrosses and improvement of general combining ability in maize population. The average grain yield increase of population Csyn 4 in MS1, MS1-HS, and MHSRRS recurrent selections was 266.7 kg ha^-1 （5.3%）, 288.0 kg ha^-1 （5.7%）, and 231.3 kg ha^-1 （4.6%） per cycle, while the grain yield of S 1 progeny of population for Csyn 4 was increased by 420.0 kg ha^-1 （10.9%）, 376.0 kg ha^-1 （9.8%）, and 414.7 kg ha^-1 （10.8%） per cycle in MS1, MS1-HS, and MHSRRS recurrent selections, respectively. linear responses （b） in the MS1, MS1-HS, and MHSRRS recurrent selections were the same as the realized responses of the selection （G） for grain yield increase of Csyn 4 and S1 progeny of the populations. The grain yield of testcrosses increased by 3.3-5.2% on average per cycle. The value of heterosis did not display any differences amongst the different cycles of selections. The GCA for yield component traits of population Csyn 4 was improved significantly by means of three selection methods, whereas the GCA for plant height, ear height, days to silking, and days to pollen did not show significant increase in the recurrent selections. GCA for the number of tassel branches were decreased in the selections, while GCA for the number of plant leaves were increased, but the difference was not significant.

关键词： maize (Zea mays L.) population improvement recurrent selection modified S 1 family selection (MS 1),modified S 1 family-half-sib family combining selection (MS 1-HS) modified half-sib reciprocal recurrentselection (MHSRRS)

Adaptive security control of time-varying constraints nonlinear cyber-physical systems with false data injection attacks

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Journal of Control and Decision 2024年第1期11卷 50-59页

作者： Yue-ming Wang Yuan-xin li Department of Science Liaoning University of TechnologyJinzhouPeople’s Republic of China

In this article,an adaptive security control scheme is presented for cyber-physical systems(CPSs)suffering from false data injection(FDI)attacks and time-varying state ***,an adaptive bound estimation mechanism is introduced in the backstepping control design to mitigate the effect of FDI ***,to solve the unknown sign time-varying statefeedback gains aroused by the FDI attacks,a type of Nussbaum function is employed in the adaptive security ***,by constructing a barrier Lyapunov function,it can be ensured that all signals of controlled system are bounded and the time-varying state constraints are not ***,the provided simulation examples demonstrate the effectiveness of the proposed controller.

关键词： Neural networks backstepping technology false data injection(FDI)attacks nonlinear cyber-physical systems controls

Redistribution of Pb, Zn and Cu Fractions in Tailing Soils Treated with Different Extractants

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Pedosphere 2006年第3期16卷 312-318页

作者： liU Yun-Guo WANG Xian-Hai ZENG Guang-ming li xin ZHOU Chun-Hua FAN Ting li Yong-li YUAN xin-Zhong Department of Environmental Science and Engineering Hunan University Changsha 410082 （China） Institute of Applied Ecology Chinese Academy of Sciences Shenyang 110016 （China） Graduate School of Chinese Academy of Sciences Beijing 100039 （China）

The efficiency of EDTA, HNO3 and CaCl2 as extractants to remove Pb, Zn and Cu from tailing soils without varying soil pH was investigated with distributions of Pb, Zn and Cu being determined before and after extraction using the sequential extraction procedure of the optimized European Community Bureau of Reference (BCR). Results indicated that EDTA and HNO3 were both effective extracting *** extractability of extractants for Pb and Zn was in the order EDTA > HNO3 > CaCl2, while for Cu it was HNO3 > EDTA > CaCl2. After EDTA extraction, the proportion of Pb, Zn and Cu in the four fractions varied greatly, which was related to the strong extraction and complexation ability. Before and after extraction with HNO3 and CaCl2, the percentages of Pb, Zn and Cu in the reducible, oxidizable and residual fractions changed little compared to the acid-extractable fraction. The lability of metal in the soil and the kinds of extractants were the factors controlling the effects of metal extraction.

关键词： BCR extraction fraction heavy metals redistribution

The influences of perforating phase and bedding planes on the fracture deflection in laminated shale

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Petroleum Science 2024年第2期21卷 1221-1230页

作者： ming-Zhe Gu Mao Sheng Xiao-Ying Zhuang xin-Yi li Gen-Sheng li National Key Laboratory of Petroleum Resources and Engineering China University of PetroleumBeijing102249China College of Petroleum Engineering China University of PetroleumBeijing102249China College of Civil Engineering Tongji UniversityShanghai200092China

The perforating phase leads to complex and diverse hydraulic fracture propagation behaviors in laminated shale formations. In this paper, a 2D high-speed imaging scheme which can capture the interaction between perforating phase and natural shale bedding planes was proposed. The phase field method was used to simulate the same conditions as in the experiment for verification and hydraulic fracture propagation mechanism under the competition of perforating phase and bedding planes was *** results indicate that the bedding planes appear to be no influence on fracture propagation while the perforating phase is perpendicular to the bedding planes, and the fracture propagates along the perforating phase without deflection. When the perforating phase algins with the bedding planes, the fracture initiation pressure reserves the lowest value, and no deflection occurs during fracture propagation. When the perforating phase is the angle 45°, 60°and 75°of bedding planes, the bedding planes begin to play a key role on the fracture deflection. The maximum deflection degree is reached at the perforating phase of75°. Numerical simulation provides evidence that the existence of shale bedding planes is not exactly equivalent to anisotropy for fracture propagation and the difference of mechanical properties between different shale layers is the fundamental reason for fracture deflection. The findings help to understand the intrinsic characteristics of shale and provide a theoretical basis for the optimization design of field perforation parameters.

关键词： Shale Propagation Perforating Bedding Structure