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Preface for the Special Issue on“Safety and Intelligent Maintenance of Offshore Structures”

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China Ocean Engineering 2024年第2期38卷 181-182页

作者： xu Wan-hai State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation Tianjin UniversityTianjin 300072China

The ocean serves as a vital carrier for human resource development and economic growth and contains rich mineral resources such as oil,natural gas,polymetallic nodules,cobalt-rich ferromanganese crusts,polymetallic sulfides,and rare earth ***,the ocean has wealthy reserves of wind,wave,tidal,and solar energy,making it an essential strategic space for sustainable future ***,offshore structures are complex.

关键词： ocean offshore tidal

Electron excitation processes in low energy collisions of hydrogen-helium atoms

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Chinese Physics B 2022年第12期31卷 213-218页

作者： Kun Wang Chuan Dong Yi-Zhi Qu Ling Liu Yong Wu xu-hai hong Robert J.Buenker Institute of Environmental Science Shanxi UniversityTaiyuan 030006China College of Optoelectronics University of Chinese Academy of SciencesBeijing 100049China National Key Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China School of Physics and Electronic Technology Liaoning Normal UniversityDalian 116029China Fachbereich C-Mathematik und Naturwissenschaften Bergische Universitat WuppertalD-42097 WuppertalGermany

The electron excitation processes of H(1s)+He(1s^(2))→H(2s/2p)+He(1s^(2))are studied in impact energy range of 20-2000 e V/u by using the quantum-mechanical molecular orbital close-coupling(QMOCC)*** and state-selective cross sections have been obtained and compared with the available theoretical and experimental *** results agree well with available measurements in the overlapping energy regions *** comparison of our results with other theoretical calculations further demonstrates the importance of considering a sufficient number of *** datasets presented in this paper,including the excitation cross sections,are openly available at https://***/10.57760/sciencedb.j00113.00083.

关键词： electron excitation processes low energy collision quantum-mechanical molecular orbital close-coupling method cross section

Efficacy Evaluation for the Treatment of Subcapital Femoral Neck Fracture in Young Adults by Capsulotomy Reduction and Closed Reduction

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Chinese Medical Journal 2015年第4期128卷 483-488页

作者： Cong Liu Meng-Ting Liu Peng Li hong-hai xu Institute of Clinical Xi'an Medical College Xi'an Shaanxi 710061 China Department of Orthopaedics Shaanxi Provincial People's Hospital Xi'an Shaanxi 710061 China

Background：Subcapital femoral neck fracture in young adults has many complications,and the incidence is increasing *** selection of the proper operation method to avoid them is an ambiguous *** study aimed to evaluate the treatment effect of subcapital femoral neck fracture by the capsulotomy and internal fixation with iliac bone grafting or closed reduction and intemal fixation in young ***：From March 2003 to February 2010,65 young patients with subcapital femoral neck fractures were treated,including 39 males and 26 females with average age of 34.5 years （range,19-50 years）; 29 cases of the left side and 36 cases of the right *** were randomly divided into Group A with 34 cases treated by closed reduction and internal fixation and Group B with 31 cases treated by the capsulotomy and internal fixation with iliac bone *** two groups had no significant differences in sex,age,body mass index and preoperative Harris Hip *** observation criteria involved the length of the incision,blood loss,operation time,nonunion rate,avascular necrosis of the femoral head （ANFH） rate and Harris Hip ***：Four of 65 patients were lost follow-up,and the follow-up rate was 93.8％,the average follow-up time was 38.7 months （range,33-47 months）.In Group A,the incision length was 5.1 ± 2.2 cm,blood loss was 84.0 ± 13.2 ml,and operation time was 52.9 ± 10.2 *** Group B,the incision length was 15.4 ± 4.6 cm,blood loss was 396.0 ± 21.3 ml,and operation time was 1 16.5 ± 15.3 *** occurred in 8 patients （25.2％） in Group A and 1 patient （3.3％） in Group *** occurred in 9 patients （29.1％） in Group A and 2 patients （6.7％） in Group *** Harris Hip Score was 89.0 ± 5.6 in Group A and 95.0 ± 4.5 in Group *** above index of two groups was considered statistically significant （P ＜ 0.05）.Conclusions：Capsulotomy and internal fixation with iliac bone grafting can improve fracture healing,reduce ANFH in young *** i

关键词： Internal Fixation Open Reduction Subcapital Femoral Neck Fracture Young Adults

A Review on Vibration Control of Multiple Cylinders Subjected to FlowInduced Vibrations

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China Ocean Engineering 2024年第2期38卷 183-197页

作者： xu Wan-hai MA Ye-xuan State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation Tianjin UniversityTianjin 300350China Institute of Mechanics Chinese Academy of SciencesBeijing 100190China

The fatigue damage caused by flow-induced vibration(FIV)is one of the major concerns for multiple cylindrical structures in many engineering *** FIV suppression is of great importance for the security of many cylindrical *** active and passive control methods have been employed for the vibration suppression of an isolated cylinder undergoing vortex-induced vibrations(VIV).The FIV suppression methods are mainly extended to the multiple cylinders from the vibration control of the isolated *** to the mutual interference between the multiple cylinders,the FIV mechanism is more complex than the VIV mechanism,which makes a great challenge for the FIV *** efforts have been devoted to vibration suppression of multiple cylinder systems undergoing FIV over the past two *** control methods,such as helical strakes,splitter plates,control rods and flexible sheets,are not always effective,depending on many influence factors,such as the spacing ratio,the arrangement geometrical shape,the flow velocity and the parameters of the vibration control *** FIV response,hydrodynamic features and wake patterns of the multiple cylinders equipped with vibration control devices are reviewed and *** FIV suppression efficiency of the vibration control methods are analyzed and compared considering different influence *** research on the FIV suppression of multiple cylinders is suggested to provide insight for the development of FIV control methods and promote engineering applications of FIV control methods.

关键词： flow-induced vibration vibration control multiple cylinders tandem side-by-side staggered

Transient responses of double-curved sandwich two-layer shells resting on Kerr's foundations with laminated three-phase polymer/GNP/fiber surface and auxetic honeycomb core subjected to the blast load

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Defence Technology（防务技术） 2024年第5期35卷 222-247页

作者： Nguyen Thi hai Van Thi hong Nguyen Researcher&Lecturer Faculty of Industrial EducationThe University of Danang-University of Technology and Education48 Cao ThangDanang550000Viet Nam Researcher&Lecturer Faculty of Mechanical EngineeringThuyloi University175 Tay SonDong DaHanoi100000Viet Nam

This work uses refined first-order shear theory to analyze the free vibration and transient responses of double-curved sandwich two-layer shells made of auxetic honeycomb core and laminated three-phase polymer/GNP/fiber surface subjected to the blast *** of the two layers that make up the double-curved shell structure is made up of an auxetic honeycomb core and two laminated sheets of three-phase polymer/GNP/*** exterior is supported by a Kerr elastic foundation with three *** key innovation of the proposed theory is that the transverse shear stresses are zero at two free surfaces of each *** contrast to previous first-order shear deformation theories,no shear correction factor is ***'s exact solution was used to treat the double-curved shell problem with a single title boundary,while the finite element technique and an eight-node quadrilateral were used to address the other boundary *** ensure the accuracy of these results,a thorough comparison technique is employed in conjunction with credible *** problem model's edge cases allow for this kind of *** study's findings may be used in the post-construction evaluation of military and civil works structures for their ability to sustain explosive *** addition,this is also an important basis for the calculation and design of shell structures made of smart materials when subjected to shock waves or explosive loads.

关键词： Blast load Two-layer shell Polymer/GNP/Fiber surface Auxetic honeycomb Shear connectors

Damping capacity of Fe_(83)Ga_(17) magnetostrictive alloy under magnetic field

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Rare Metals 2024年第1期43卷 402-409页

作者： Shao-Wen Yan Xing Mu Bing-Jie Liu Li-hong xu Shi-hai Guo Yan Qi hong-Ping Zhang Department of Functional Material Research Central Iron and Steel Research InstituteBeijing 100081China

The damping performance of Fe_(83)Ga_(17) alloys has been investigated in the static magnetic field (H). The results demonstrate that the damping peak value can be adjusted between 0.020 and 0.085 under the magnetic f... 详细信息

关键词： alloy magnetic alloys

Temperature variations in the past 6000 years inferred from δ^(18)O of peat cellulose from hongyuan,China

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Chinese Science Bulletin 2002年第18期47卷 1578-1584页

作者： xu hai, hong Yetang, LIN Qinghua, hong Bing, JIANG hongbo & ZHU YongxuanInstitute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China Graduate School of Chinese Academy of Sciences, Beijing 100039, China Institute of Geochemistry Chinese Academy of Sciences Guiyang China Graduate School of Chinese Academy of Sciences Beijing China

Trends of the temperature variations recorded in δ18O in hongyuan peat cellulose are similar to those recorded in δ18O of Jinchuan peat cellulose and in δ18O of Dunde ice core. Climate events have been identified to be globally homogeneous. Two notable climate transition periods have been detected in the past 6000 years, namely 4000 aBP with climate shifting from cold to warm and 1500 aBP with climate shifting from warm to relatively cold. Power spectrum analysis was performed to investigate the periodical signals in the δ18O time series. Typical periodicities of 1200-1087 a, 752 a, 444 a, 325 a, 213 a, 127-123 a, 88 a, 79 a were discovered, indicating an integrated influence on hongyuan climate from solar, monsoon and ocean activities. Solar forcing has been addressed to be the main driving forcing of hongyuan climate.

关键词： hongyuan oxygen isotopic composition peat tempera-ture.

Fracture sealing performance of granular lost circulation materials at elevated temperature:A theoretical and coupled CFD-DEM simulation study

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Petroleum Science 2024年第1期21卷 567-581页

作者： Chong Lin Qi-Cong xu Lie-Xiang Han Gao Li hai He hong-Ling Zhou Ji-Ping She CCDC Drilling&Production Technology Research Institute Guanghan618300SichuanChina State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500SichuanChina College of Materials Science and Engineering Chongqing UniversityChongqing400044China State Key Lab of Oil and Gas Reservoir Geology and Exploitation(Chengdu University of Technology) Chengdu610059SichuanChina College of Energy Chengdu University of TechnologyChengdu610059SichuanChina

Lost circulation is a common downhole problem of drilling in geothermal and high-temperature,high-pressure(HTHP)*** circulation material(LCM)is a regular preventive and remedial measure for lost ***,conventional LCMs seem ineffective in high-temperature *** may be due to the changes in the mechanical properties of LCMs and their sealing performance under high-temperature *** understand how high temperature affects the fracture sealing performance of LCMs,we developed a coupled computational fluid dynamics-discrete element method(CFD-DEM)model to simulate the behavior of granular LCMs in *** summarized the literature on the effects of high temperature on the mechanical properties of LCMs and the rheological properties of drilling *** conducted sensitivity analyses to investigate how changing LCM slurry properties affected the fracture sealing efficiency at increasing *** results show that high temperature reduces the size,strength,and friction coefficient of LCMs as well as the drilling fluid ***,softer,and less frictional LCM particles have lower bridging probability and slower bridging *** particles tend to form dual-particle bridges rather than single-particle *** result in a deeper,tighter,but unstable sealing *** drilling fluid viscosity leads to faster and shallower sealing zones.

关键词： Geothermal well drilling HTHP formationLost circulation material CFD-DEM Fracture sealing

A Rendezvous Mission to the Second Earth Trojan Asteroid 2020 XL_5 with Low-Thrust Multi-Gravity Assist Techniques

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Research in Astronomy and Astrophysics 2024年第1期24卷 245-264页

作者： Shi-hai Yang Bo xu Xin Li School of Aeronautics and Astronautics Sun Yat-sen UniversityShenzhen 518107China

As the second of Earth's Trojan asteroids, 2020 XL_(5) is worthy of rendezvous and even sample return missions in many aspects. In this paper, a rendezvous mission to Earth's second Trojan asteroid 2020 XL_(5) is ***, due to its high inclination and large eccentricity, direct impulsive transfer requires large amounts of fuel consumption. To address this challenge, we explore the benefits of electric propulsion and multi-gravity assist techniques for interplanetary missions. These two techniques are integrated in this mission design. The design of a low-thrust gravity-assist(LTGA) trajectory in multi-body dynamics is thoroughly investigated,which is a complex process. A comprehensive framework including three steps is presented here for optimization of LTGA trajectories in multi-body dynamics. The rendezvous mission to 2020 XL_(5) is designed with this three-step approach. The most effective transfer sequence among the outcomes involves Earth–Venus–Earth–Venus-2020 XL_(5). Numerical results indicate that the combination of electric propulsion and multi-gravity assists can greatly reduce the fuel consumption, with fuel consumption of 9.03%, making it a highly favorable choice for this rendezvous mission.

关键词： minor planets asteroids:general celestial mechanics Planetary Systems