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Improvement of 2.79-μm laser performance on laser diode side-pumped GYSGG/Er,Pr:GYSGG bonding rod with concave end-faces

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Chinese Physics B 2019年第11期28卷 186-192页

作者： Xu-Yao Zhao Dun-Lu Sun Jian-Qiao Luo Hui-Li Zhang Zhong-Qing Fang Cong Quan Lun-Zhen Hu Zhi-Yuan Han Mao-Jie Cheng Shao-Tang Yin The Key Laboratory of Photonic Devices and Materials Anhui ProvinceAnhui Institute of Optics and Fine MechanicsChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230022China

A comparative study on the laser performance between bonding and non-bonding Er,Pr:GYSGG rods side-pumped by 970-nm laser diodes(LDs) is conducted for the thermal lensing compensation. The analyses of the thermal distribution and thermal focal length show that the bonding rod possesses a high cooling efficiency and weak thermal lensing effect compared with the conventional Er,Pr:GYSGG rod. Moreover, the laser characteristics of maximum output power, slope efficiency, and laser beam quality of the bonding rod with concave end-faces operated at 2.79 μm are improved under the high-repetition-rate operation. A maximum output power of 13.96 W is achieved at 150-Hz and 200-μs pulse width,corresponding to a slope efficiency of 17.7% and an electrical-to-optical efficiency of 12.9%. All results suggest that the combination of thermal bonding and concave end-face is a suitable structure for thermal lensing compensation.

关键词： laser performance GYSGG/Er Pr:GYSGG bonding rod thermal lensing compensation concave end-faces

Dynamic Response Study of Steel Catenary Riser Based on Slender rod Model

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China Ocean Engineering 2019年第1期33卷 57-64页

作者： LIU Zhen GUO Hai-yan College of Engineering Ocean University of China

A numerical model of the steel catenary riser(SCR) is built based on the slender rod model. The slender rod model,which describes the behavior of the slender riser in terms of the center line position, can solve the geometrical nonlinearity effectively. In a marine environment, the SCR is under the combined internal flow and external loads,such as wave and current. A general analysis considers only the inertial force and the drag force caused by the wave and current. However, the internal flow has an effect on the SCR; it is essential to explore the dynamic response of the SCR with the internal flow. The SCR also suffers the lift force and the fluctuating drag force because of the current. Finite element method is utilized to solve the motion equations. The effects of the internal flow, wave and current on the dynamic response of the SCR are considered. The results indicate that the increase of the internal flow density leads to the decrease of the displacement of the SCR, while the internal flow velocity has little effect on the SCR. The displacement of the SCR increases with the increase of the wave height and period. And the increasing wave period results in an increase in the vibration period of the SCR. The current velocity changes the displacements of the SCR in x-and z-directions. The vibration frequency of the SCR in y-direction increases with the increase of the current velocity.

关键词： steel catenary riser slender rod model internal flow dynamic response

Influence of Extrusion Speed on the Microstructure Evolution, Interface Bonding and Mechanical Response of Mg MB26/Al 7075 Composite rod

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Acta Metallurgica Sinica(English Letters) 2019年第2期32卷 253-262页

作者： Yu Chen Rui Zhang Tao Zhou Li Hu Jian Tu Lai-Xin Shi Yan Zhi Li-Wei Lu Qiang Chen Ben-Hong Liao Lei Liu Wen-Jun Ge Jing Xiao Ming-Bo Yang College of Material Science and Engineering Chongqing University of Technology Institute of Light Metal Structural Materials Hunan University of Science and Technology Southwest Technology and Engineering Research Institute Precision Forming Integrated Manufacturing Technology of Collaborative Innovation Center

The Mg MB26/Al 7075 composite rod,in which Mg MB26 serves as the sleeve and Al 7075 serves as the core,is fabricated via the process of *** influence of extrusion speed on the microstructure evolution,interface bonding and mechanical response of the Mg MB26/Al 7075 composite rod is *** results show that the typical extrusion texture of Mg sleeve does not change during co-extrusion;however,the average grain size in the Mg sleeve slightly changes from 1.57 lm in the case of extrusion speed of 0.3 mm/s to 2.78 lm in the case of extrusion speed of2.1 mm/*** thickness of interface transition layer increases significantly from 5.5 to 50 lm,and therefore,the interface bonding becomes deteriorative with increasing extrusion speed;in particular,many cavities emerge in the case of 1.2 and2.1 mm/s.

关键词： MB26/7075 composite rod Extrusion speed Microstructure evolution Interface bonding Mechanical response

Some Interesting Traveling Waves in a Transversely Isotropic Incompressible Hyperelastic Semi-infinite rod

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Acta Mechanica Solida Sinica 2018年第6期31卷 698-716页

作者： Ran Wang Xuegang Yuan Hongwu Zhang Jie Xu Jing Zhang State Key Laboratory of Structural Analysis for Industrial Equipment Department of Engineering MechanicsDalian University of TechnologyDalian 116024China College of Science Dalian Minzu UniversityDalian 116600China College of Mathematics and Information North Minzu UniversityYinchuan 750021China

In this paper,the bounded traveling wave solutions are examined for a system of partial differential equations with certain boundary ***,this system can be used to describe the axially symmetric motion of a semi-infinite incompressible hyperelastic cylindrical *** the aid of traveling wave transformations,the partial differential equations can be reduced to a traveling wave *** implicit analytical expressions determining the traveling waves are ***,the influences of material parameters on the qualitative properties are discussed in detail by using the phase portraits of the traveling wave system. Smooth solutions such as the periodic traveling wave solutions and the solitary wave solutions with the peak form are *** particular,some interesting singular traveling wave solutions including the solitary cusp wave solutions and the periodic cusp wave solutions with the peak form are *** examples for all these waves are given.

关键词： Semi-infinite cylindrical rod Planar dynamical system Bound traveling wave Solitary cusp wave

Streamwise vortex generation by the rod

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Chinese Journal of Aeronautics 2019年第8期32卷 1903-1911页

作者： Ryszard SZWABA Pawel FLASZYNSKI Piotr DOERFFER Department of Experimental Aerodynamics Institute of Fluid Flow Machinery Polish Academy of Sciences

The technology development related to aerodynamics is leading to ever increasing loads of wings, airfoils and turbine and compressor blades. The increase in aerodynamic forces is often leading to flow separation and depreciation of the aerodynamic performance of flying objects or propulsion systems. Flow control methods are required to avoid these negative effects. In the recent two decades the flow control by means of air-jet vortex generators has been also intensively investigated. In this method a streamwise vortex is introduced by an oblique jet. The necessity to supply air by a pipe system may be considered a disadvantage. In order to eliminate this feature, it has been proposed to put out a rod instead of a jet. It has been shown that the application of a rod can introduce the same effect as a jet, as long as the streamwise vortex generation is concerned and appropriate dimensions are used. The present paper focuses on the influence of rod vortex generators on a flow pattern downstream. The results presented here concern experimental and numerical investigations and provide guidelines for the design of a new flow control method dedicated mainly to external flows.

关键词： Air-jet vortex generator Boundary layer Flow control rod vortex generator Streamwise vortices

Austenite grain growth and its effect on splitting fracture property of a V-N microalloyed medium carbon steel connecting rod

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Journal of Iron and Steel Research International 2019年第8期26卷 875-881页

作者： Chao-lei Zhang Wen Fang Bao-run Cai Xiao-hang Sun Ya-zheng Liu School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Xining Special Steel Co. Ltd. Xining 810005 Qinghai China

The growth behaviour of austenite grain in a V-N microalloyed medium carbon steel and its effect on splitting fracture property were investigated by mechanical tests, fracture morphology and microstructure analysis. When the heating temperature is 800℃, the austenite grain size is 7.6 μm, and the fracture surface is uneven with the impact energy of 235.9 J. When the heating temperature increases to 1100 ℃, the austenite grain size grows up to 65.5 μm and the impact fracture surface is much more even with the impact energy of 13.6 J. It is believed that the coarse austenite grain size of 65.5 μm is beneficial for the splitting fracture property of V-N microalloyed medium carbon steel connecting rod. In addition, austenite grain sizes of V-N microalloyed medium carbon steel increase with the increasing in heating tem-perature and holding time. Then, a grain growth model is established to predict austenite grain growth behaviour.

关键词： Connecting rod Splitting fracture property Microstructure Austenite grain

Thermal behavior of the HTR-10 under combined PLOFC and ATWS condition initiated by unscrammed control rod withdrawal

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Nuclear Science and Techniques 2018年第9期29卷 130-138页

作者： Feng Gou Yuan Liu Fu-Bing Chen Yu-Jie Dong Institute of Nuclear and New Energy Technology Tsinghua University Collaborative Innovation Center of Advanced Nuclear Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety Ministry of Education

Two tests initiated by unscrammed control rod withdrawal were performed on the High Temperature GasCooled Reactor-Test Module(HTR-10) in November 2003 after the reactor achieved its full power, and the test conditions represented a typical transient scenario of modular high-temperature reactors(HTRs), called pressurized loss of forced cooling, and anticipated transient without *** on the test parameters, the HTR-10 thermal behaviors under the test conditions were studied with the help of the system analysis code THERMIX. The combination of the test results and the investigation results makes the HTR-10 safety potential better understood. Key phenomena, such as the helium natural circulation and the temperature redistribution in the reactor, were revealed. As the safety feature of most significance, there is a large margin between the maximum fuel temperature and its safety limit in each test. Temperatures of thermocouples in different components were calculated by THERMIX and compared with the test values. The applicability of the code was verified by good agreement obtained from the comparison.

关键词： HTR-10 Control rod withdrawal ATWS THERMIX

Variational principle for a special Cosserat rod

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Applied Mathematics and Mechanics(English Edition) 2009年第9期30卷 1169-1176页

作者：刘东生 Charles H-T WANG Applied Mathematics Department Nanjing University of Science and Technology School of Engineering and Physical Sciences University of Aberdeen

In this paper, we describe the nonlinear models of a rod in three-dimensional space based on the Cosserat theory. Using the pseudo-rigid body method and variational principle, we obtain the motion equations of a Cosse... 详细信息

关键词： rod variational principle Cosserat theory

Microstructural observations on the terminal penetration of long rod projectile

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Defence Technology（防务技术） 2017年第6期13卷 413-421页

作者： Krushna Kumbhar P.Ponguru Senthil A.K.Gogia Armour Design and Development Division Defence Metallurgical Research LaboratoryHyderabad 500058India

Present study focuses on the terminal penetration of tungsten heavy alloy(WHA) long rod penetrator impacted against armour steel at an impact velocity of 1600 m/s. The residual penetrator and armour steel target recovered after the ballistic test have been characterized using optical microscope, scanning electron microscope(SEM) and electron probe micro analyzer(EPMA). Metallurgical changes in target steel and WHA remnant have been analysed. Large shear stresses and shear localization have resulted in local failure and formation of erosion products. Severe plastic deformation acts as precursor for formation of adiabatic shear band(ASB) induced cracks in target steel. Recovered WHA penetrator remnant also exhibits severe plastic deformation forming localized shear bands, ASB induced cracks and shock induced cracks.

关键词： Long rod projectile Terminal penetration Shear localization Adiabatic shear band Tungsten heavy alloy Armour steel