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Chemical Research in Chinese Universities 2007年第6期23卷 720-725页

作者： ZHENG Yan yang Bing ZHANG hai-quan LU Ping SHEN Fang-zhong LIU Lin-lin xu hai yang Guang-di MA Yu-guang Key Lab for Supramolecular Structure and Materials of Ministry of Education Jilin University Changchun 130012 P. R. China

A soluble poly（meta-phenylene） derivative with rigid twisted biphenyl unit was synthesized by the Yamamoto coupling reaction. The polymer is soluble in common organic solvents, and the number-average molecular weight is about 6500. The UV-Vis and quantum chemical calculation indicate that the different conformation segments named ＂conformers＂ exist in the polymer backbones; it was also further confirmed by the single crystal X-ray diffraction study of the dimeric model compound. The π-π^＊ transition of biphenyl segments of twisted and planar conformations made the polymer exhibit a strong absorption around 256 nm and a weak absorption at about 300 nm. Furthermore, the polymer exhibits a strong UV photoluminescence at 372 nm when the excitation wavelengths are longer than 300 run. The ultraviolet-emitting electroluminescence（EL） device with the single layer structure shows EL λmax of the derivative at 370 nm.

关键词： Poly(phenylene) Conformation UV light-emitting

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核级电动执行机构防腐研究

阀门 2024年第3期 300-304,314页

作者：张世炜许海洋童少飞扬州电力设备修造厂有限公司江苏扬州225000

海洋环境是最为恶劣的自然腐蚀环境,海洋腐蚀问题是海洋工程设备安全服役面临的主要威胁。本文针对目前电动执行机构海洋平台的开发研究现状及未来发展趋势,介绍了海洋腐蚀环境特点,分析了我国海洋腐蚀防护现状及需求,概述了核级电动执... 详细信息

海洋环境是最为恶劣的自然腐蚀环境,海洋腐蚀问题是海洋工程设备安全服役面临的主要威胁。本文针对目前电动执行机构海洋平台的开发研究现状及未来发展趋势,介绍了海洋腐蚀环境特点,分析了我国海洋腐蚀防护现状及需求,概述了核级电动执行机构中,采用阳极氧化工艺的铸铝零件和达克罗工艺的球墨铸铁零件在海洋环境下的腐蚀与防护研究进展。叙述了其在海洋环境各种因素影响下的腐蚀行为和机理,采用盐雾试验模拟海洋环境,以探究通过微合金化技术和表面镀层技术提高设备的耐蚀性行为。

关键词：盐雾试验海洋防腐电动执行机构阳极氧化达克罗球墨铸铁

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

Innovative superheated steam impingement blanching(SSIB)enhances drying rate and quality attributes of line pepper

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Information Processing in Agriculture 2017年第4期4卷 283-290页

作者： xu-hai yang Qian Zhang Jun Wang Li-Zhen Deng Za Kan College of Mechanical and Electrical Engineering Shihezi UniversityShihezi 832001China College of Engineering China Agricultural UniversityP.O.Box 19417 Qinghua DongluBeijing 100083China

Blanching is an essential step before processing of agricultural products as it can inactivate enzymes that cause undesirable *** current work the effects of superheated steam impingement blanching(SSIB)time and temperature on drying characteristics and red pigments content of line pepper were *** showed that after a 3-min SSIB pretreatment at 110℃ the pepper epidermis covered with wax coat was *** addition,the drying time was extensively decreased and the loss of red pigments of dried products was *** showed that the whole drying process took place in the falling rate period,which indicated that diffusion was the dominant physical mechanism governing moisture movement in the ***,the second Fick’s law of diffusion was used to determine the effective moisture diffusivity(Deff)of line pepper,which increased from 1.193×10^-10 to 3.128×10^-10 m^2/s with increasing of the drying temperature and air *** drying activation energy(Ea)of pretreated samples was 34.31 kJ/mol,which decreased by 3% compared with the non-pretreatment *** findings of this work indicate that SSIB is very promising pretreatment technique as it not only enhances drying process but also improves bioactive substance preservation of red pepper.

关键词： Line pepper High-humidity hot air impingement blanching Air impingement drying Drying characteristics Quality attributes

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

Multiparameter Numerical Investigation of Two Types of Moving Interactions Between the Deep-Sea Mining Vehicle Track Plate and Seabed Soil:Digging and Rotating Motions

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China Ocean Engineering 2024年第3期38卷 408-423页

作者： SUN Peng-fei LYU hai-ning yang Jian-min xu Zhi-yong State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai 200240China Yazhou Bay Institute of Deepsea SCI-TECH Shanghai Jiao Tong UniversitySanya 572024China Institute of Marine Equipment Shanghai Jiao Tong UniversityShanghai 200240China

To ensure the safe performance of deep-sea mining vehicles(DSMVs),it is necessary to study the mechanical characteristics of the interaction between the seabed soil and the track *** rotation and digging motions of the track plate are important links in the contact between the driving mechanism of the DSMV and seabed *** this study,a numerical simulation is conducted using the coupled Eulerian–Lagrangian(CEL)large deformation numerical method to investigate the interaction between the track plate of the DSMV and the seabed soil under two working conditions:rotating condition and digging ***,a soil numerical model is established based on the elastoplastic mechanical characterization using the basic physical and mechanical properties of the seabed soil obtained by in situ ***,the soil disturbance mechanism and the dynamic mechanical response of the track plate under rotating and digging conditions are obtained through the analysis of the sensitivity of the motion parameters,the grouser structure,the layered soil features and the soil *** results indicate that the above parameters remarkably influence the interaction between the DSMV and the seabed ***,it is important to consider the rotating and digging motion of the DSMV in practical engineering to develop a detailed optimization design of the track plate.

关键词： deep-sea mining vehicle rotating motion digging motion track plate-seabed soil interaction CEL numerical method

State and parameter identification of linearized water wave equation via adjoint method

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Science China(Information Sciences) 2024年第10期67卷 283-297页

作者： yang YU Cheng-Zhong xu hai-Long PEI Jinpeng YU School of Automation Qingdao University LAGEP Batiment CPE University Claude Bernard-Lyon 1 School of Automation Science and Engineering Key Laboratory of Autonomous Systems and Networked ControlMinistry of Education Guangdong Engineering Technology Research Center of Unmanned Aerial Vehicle SystemSouth China University of Technology

In this paper, we focus on the state and parameter identification problem of a hydrodynamical system. This system is modeled as a linearized water wave equation(LWWE), a hyperbolic state-space model coupled with a Laplace equation. We assume that the wave elevation at two distinct points is the only measurement of water waves. We show that the state and water depth can be reconstructed from this point measurement records. The identification problem is recast as an optimization problem over an infinite-dimensional space. We propose the adjoint method-based identification algorithm to generate an estimated state and water depth. We then performed a numerical simulation to show the effectiveness of our designed algorithm by comparing it with existing studies.

关键词： linearized water wave equation (LWWE) point observation state estimation parameter identification adjoint method numerical simulation

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Towards the insights into the deactivation behavior of acetylene hydrogenation catalyst

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Petroleum Science 2024年第2期21卷 1405-1414页

作者： hai-Xia Su yang Jiao Jian-Gong Shi Zhi-Wei Yuan Di Zhang xu-Peng Wang Jing Ren Dan Liu Jian-Zhou Gui hai-yang Gao Xiao-Li xu State Key Laboratory of Separation Membranes&Membrane Processes Tianjin Key Laboratory of Green Chemical Technology and Process EngineeringSchool of Material Science and EngineeringTiangong UniversityTianjin300387China Institute of Engineering Technology Sinopec Catalyst Co.LtdBeijing101100China State Key Laboratory of Separation Membranes and Membrane Processes Tianjin Key Laboratory of Green Chemical Technology and Process EngineeringSchool of ChemistryTiangong UniversityTianjin300387China

A series of model catalysts were obtained by treating commercial fresh and spent catalysts unloaded from the factory with different methods, including green oil dipping, extraction and high-temperature regeneration;finally, the deactivation behavior of the commercial catalyst for acetylene hydrogenation were studied. The influence of various possible deactivation factors on the catalytic performance was elucidated via detailed structural characterization, surface composition analysis, and activity *** results showed that green oil, carbon deposit and sintering of active metal were the main reasons for deactivation, among which green oil and carbon deposit led to rapid deactivation, while the activity could be recovered after regeneration by high-temperature calcination. The sintering of active metal components was attributed to the high-temperature regeneration in hydrothermal conditions, which was slow but irreversible and accounted for permanent deactivation. Thus, optimizing the regeneration is expected to extend the service life of the commercial catalyst.

关键词： Acetylene Hydrogenation Green oil Carbon deposit Sintering Catalyst deactivation

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

Direct Digital Frequency Control Based on the Phase Step Change Characteristic between Signals

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Chinese Physics Letters 2017年第9期34卷 29-32页

作者： Zhao-Min Jia xu-hai yang[[ Bao-Qi Sun[[ Xiao-Ping Zhou Bo Xiang Xin-Yu Dou National Time Service Centre Chinese Academy of Sciences Xi＇an 710600 School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing 100049 Key Laboratory of Precise Positioning and Timing Technology Chinese Academy of Sciences Xi＇an 710600 Intelligence and Information Engineering College Tangshan University Tangshan 063020 China Academy of Space Technology （Xi＇an） Xi＇an 710000

We present a new digital phase lock technology to achieve the frequency control and transformation through high precision multi-cycle group synchronization between signals without the frequency transformation circuit. In the case of digital sampling, the passing zero point of the phase of the controlled signal has the phase step characteristic, the phase step of the passing zero point is monotonic continuous with high resolution in the phase lock process, and using the border effect of digital fuzzy area, the gate can synchronize with the two signals, the quantization error is reduced. This technique is quite different from the existing methods of frequency transformation and frequency synthesis, the phase change characteristic between the periodic signals with different nominal is used. The phase change has the periodic phenomenon, and it has the high resolution step value. With the application of the physical law, the noise is reduced because of simplifying frequency transformation circuits, and the phase is locked with high precision. The regular phase change between frequency signals is only used for frequency measurement, and the change has evident randomness, but this randomness is greatly reduced in frequency control, and the certainty of the process result is clear. The experiment shows that the short term frequency stability can reach 10-12/s orders of magnitude.

关键词： Direct Digital Frequency Control Based on the Phase Step Change Characteristic between Signals