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A Scaled Underwater Launch System Accomplished by Stress Wave Propagation Technique

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Chinese Physics Letters 2011年第2期28卷 136-139页

作者： wei yan-peng WANG Yi-wei FANG Xin HUANG Chen-Guang DUAN Zhu-Ping Key Laboratory of Hydrodynamics and Ocean Engineering Institute of MechanicsChinese Academy of SciencesBeijing 100190 The State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190

A scaled underwater launch system based on the stress wave theory and the slip Hopkinson pressure bar(SHPB)technique is developed to study the phenomenon of cavitations and other hydrodynamic features of high-speed submerged *** present system can achieve a transient acceleration in the water instead of long-time acceleration outside the *** projectile can obtain a maximum speed of 30m/s in about 200μs by the SHPB *** cavitation characteristics in the stage of acceleration and deceleration are captured by the high-speed camera.

关键词： acceleration cavitation system

Hydrogen Sulfide Promotes Root Organogenesis in Ipomoea batatas, Salix matsudana and Glycine max

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Journal of Integrative Plant Biology 2009年第12期51卷 1086-1094页

作者： Hua Zhang Jun Tang Xiao-Ping Liu Yun Wang wei Yu wei-yan peng Fang Fang Dai-Fu Ma Zhao-Jun wei Lan-Ying Hu School of Biotechnology and Food Engineering Hefei University of Technology Hefei 230009 China Xuzhou Sweet Potato Research Center Chinese Academy of Agricultural Sciences National Sweet Potato Improvement Center Xuzhou 221 121 China Anhui Academy of Agricultural Sciences Hefei 230031 China

In this report, we demonstrate that sodium hydrosulfide （NariS）, a hydrogen sulfide （H2S） donor, promoted adventitious root formation mediated by auxin and nitric oxide （NO）. Application of the HzS donor to seedling cuttings of sweet potato （Ipomoea batatas L.） promoted the number and length of adventitious roots in a dose-dependent manner. It was also verified that H2S or HS- rather than other sulfur-containing components derived from NariS could be attributed to the stimulation of adventitious root formation. A rapid increase in endogenous H2S, indole acetic acid （IAA） and NO were sequentially observed in shoot tips of sweet potato seedlings treated with HallS. Further investigation showed that H2S-mediated root formation was alleviated by N-1-naphthylphthalamic acid （NPA）, an IAA transport inhibitor, and 2-（4-carboxyphenyl）. 4,4,5,5-tetramethylimidazoline-1-oxyl-3-0xide （cPTIO）, an NO scavenger. Similar phenomena in H2S donor-dependent root organogenesis were observed in both excised willow （Salix matsudana var. tortuosa Vilm） shoots and soybean （Glycine max L.） seedlings. These results indicated that the process of H2S-induced adventitious root formation was likely mediated by IAA and NO, and that H2S acts upstream of IAA and NO signal transduction pathways.

关键词： auxin hydrogen sulfide nitric oxide root organogenesis sweet potato.

Thermal and mechanical behavior of casting copper alloy wheel during wheel and belt continuous casting process

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China Foundry 2024年第1期21卷 82-90页

作者： Kun Gao yan peng School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004HebeiChina

To investigate the thermal and mechanical behavior of casting wheel,a two-dimensional thermoelastic-plastic finite element model was used to predict the temperature,stress and distortion distribution of the casting wheel during the wheel and belt continuous casting *** effects of grinding thickness and casting speed on the thermal and mechanical behaviors of the center of the hot face of the casting wheel were discussed in *** each rotation,the casting wheel passes through four different spray *** results show that the temperature distribution of the casting wheel in different spray zones is similar,the temperature of the hot face is the highest and the temperature reaches the peak in the spray zoneⅢ.The stress and distortion depend on the temperature distribution,and the maximum stress and distortion of the hot face are 358.2 MPa and 1.82 mm,*** temperature at the center of the hot face decreases with increasing grinding thickness and increases with increasing casting speed.

关键词： casting wheel finite element model grinding thickness casting speed hot face spray zones

Numerical simulation of fluid flow and free surface fluctuations during wheel and belt casting process

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Journal of Iron and Steel Research International 2024年第5期31卷 1117-1126页

作者： Kun Gao yan peng National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan UniversityQinhuangdao066004HebeiChina

The unstable fluid flow and severe free surface fluctuations in the wheel and belt caster can affect the quality of the cast *** lower level height tends to entrap inclusions in the molten *** the other hand,the higher level height makes the production process more dangerous due to the overflow of high temperature fluid from the mold.A computational model of the molten metal pouring process was *** transient fluid flow and free surface fluctuations behavior were calculated using the three-dimensional large eddy simulation model and the volume of fluid *** results show that the flow velocity of the main jet gradually decreases under the influence of the low kinetic energy fluid in the *** is an obvious oscillation in the tail of the jet,while the flow field is asymmetric in *** jet is closer to the inside radius side due to the Coanda effect,and there is a recirculation zone on the inside radius and the outside radius respectively,according to the 10 s time-averaged *** with the industrial observation and simulation results,the shape of the free surface is a wave that varies with *** addition,the free surface height is lowest and the flow velocity is highest in the region near the jet.

关键词： Fluid flow Free surface Wheel and belt caster Large eddy simulation Volume of fluid method

A Novel Micro-Scale Plastic Deformation Feature on a Bulk Metallic Glass Surface under Laser Shock Peening

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Chinese Physics Letters 2013年第3期30卷 112-115页

作者： wei yan-peng wei Bing-Chen WANG Xi XU Guang-Yue LI Lei WU Xian-Qian SONG Hong-wei HUANG Chen-Guang Key Laboratory for Mechanics in Fluid-Solid Coupling Systems Chinese Academy of SciencesBeijing 100190 Key Laboratory of Microgravity(National Microgravity Laboratory) Institute of MechanicsChinese Academy of SciencesBeijing 100190 Sinosteel Corporation Beijing 100190

Laser shocking peening is a widely applied surface treatment technique that can effectively improve the fatigue properties of metal *** observe many micro-scale arc plastic steps on the surface of Zr_(47.9)Ti_(0.3)Ni_(3.1)Cu_(39.3)Al_(9.4) metallic glass subjected to the ultra-high pressure and strain rate induced by laser shock *** scanning electronic microscopy and atomic force microscopy show that the arc plastic step(APS)has an arc boundary,50–300 nm step height,5–50μm radius and no preferable *** APSs have the ability to accommodate plastic deformation in the same way as shear *** may indicate a new mechanism to accommodate the plastic deformation in amorphous metallic glass under high pressure,ultra-high strain rates,and short duration.

关键词： deformation fatigue metallic

Multiple damage zones around hydraulic fractures generated by high-frequency pulsating hydraulic fracturing

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Petroleum Science 2024年第4期21卷 2688-2702页

作者： yan peng Sheng-Jie wei Guang-Qing Zhang Da-wei Zhou Chuang-Chao Xu School of Petroleum Engineering China University of Petroleum PetroChina Changqing Oilfield Company

Pulsating hydraulic fracturing(PHF) is a promising fracturing method and can generate a dynamic periodic pressure. The periodic pressure can induce fatigue failure of rocks and decrease initiation pressure of fracture. If the frequency of periodic pressure exceeds 10 Hz, the distribution of pressure along the main fracture will be heterogeneous, which is much different from the one induced by the common fracturing method. In this study, the impact of this special spatial feature of pressure on hydraulic fracture is mainly investigated. A coupled numerical simulation model is first proposed and verified through experimental and theoretical solutions. The mechanism of secondary fracture initiation around the main fracture is then discovered. In addition, sensitivity studies are conducted to find out the application potential of this new method. The results show that(1) this coupled numerical simulation model is accurate. Through comparison with experimental and theoretical data, the average error of this coupled model is less than 1.01%.(2) Even if a reservoir has no natural fracture, this heterogeneous distribution pressure can also cause many secondary fractures around the main fracture.(3) The mechanism of secondary fracture initiation is that this heterogeneous distribution pressure causes tensile stress at many locations along the main fracture.(4) Through adjusting the stimulation parameters, the stimulation efficiency can be improved. The average and amplitude of pressure can increase possibility of secondary fracture initiation. The frequency of this periodic pressure can increase number of secondary fractures. Even 6 secondary fractures along a 100 m-length main fracture can be generated.(5) The influence magnitudes of stimulation parameters are larger than ones of geomechanical properties, therefore, this new fracturing method has a wide application potential.

关键词： Tight reservoir Reservoir stimulation Numerical simulation Secondary fracture Fracture initiation

Shedding Phenomenon of Ventilated Partial Cavitation around an Underwater Projectile

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Chinese Physics Letters 2012年第1期29卷 176-179页

作者： WANG Yi-wei HUANG Chen-Guang DU Te-Zhuan WU Xian-Qian FANG Xin LIANG Nai-Gang wei yan-peng Key Laboratory of Hydrodynamics and Ocean Engineering Institute of MechanicsChinese Academy of SciencesBeijing 100190 The State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190

A new shedding phenomenon of ventilated partial cavitations is observed around an axisymmetric projectile in a horizontal launching *** experiment system is established based on SHPB launching and high speed photography.A numerical simulation is carried out based on the homogeneous mixture approach,and its predicted evolutions of cavities are compared with the experimental *** cavity breaks off by the interaction between the gas injection and the re-entry jet at the middle location of the projectile,which is obviously different from natural *** mechanism of cavity breaking and shedding is investigated,and the influences of important factors are also discussed.

关键词： cavitation breaking system

Weak interaction-steered evolution of polyoxovanadate-based metal-organic polyhedra from transformation via interlock to packing

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Chinese Chemical Letters 2024年第2期35卷 527-533页

作者： yan-Hu Wang Ke-wei Tong Chao-Qin Chen Jing Du peng yang College of Chemistry and Chemical Engineering Advanced Catalytic Engineering Research Center of the Ministry of EducationHunan UniversityChangsha 410082China College of Chemistry and Materials Science Testing and Analysis CenterHebei Normal UniversityShijiazhuang 050024China

A bottleneck in biomimetic synthesis consists in the full copy of,for example,the hierarchical structure of proteins directed by weak *** contrast with covalent bonds bearing definite orientation and high stability,weak intermolecular forces within a continuous dynamic equilibrium can be hardly tamed for molecular *** this endeavor,a ligand-dominated strategy that embodies tunable electrostatic repulsion andπ···πstacking was first employed to shape polyoxovanadate-based metal-organic polyhedra(VMOPs).Structural evolution involving transformation,interlock,and discovery of an unprecedented prototype of the Star of David was hence *** only as a handy tool for the primary structural control over VMOPs,these weak forces allow for an advanced management on the spatial distribution of such manmade macromolecules as well as the associated physicochemical behaviors,representing an ideal model for simulating and interpreting the conformation-function relationship of proteins.

关键词： Polyoxometalates Polyoxovanadates Metal-organic polyhedron Interlock Weak intermolecular forces

Overlapping infections of Mycobacterium canariasense and Nocardia farcinica in an immunocompetent patient:A case report

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World Journal of Clinical Cases 2024年第12期12卷 2079-2085页

作者： Hai-yan Huang Kun-peng Bu Jin-wei Liu Jing wei Department of Comprehensive Internal Medicine The Affiliated Cancer Hospital of Guangxi Medical UniversityNanning 530021Guangxi Zhuang Autonomous RegionChina Department of Doppler Ultrasound The Second Nanning People's HospitalNanning 530021Guangxi Zhuang Autonomous RegionChina

BACKGROUND Infections by non-tuberculous mycobacteria(NTM)have become more common in recent *** canariasense(***)was first reported as an opportunistic pathogen in 2004,but there have been very few case reports since *** is a genus of aerobic and Gram-positive bacilli,and these species are also opportunistic pathogens and in the Mycobacteriales *** methods for diagnosis of NTM are *** next-generation sequencing(mNGS)can rapidly detect many pathogenic microorganisms,even rare *** NTM and Nocardia infections occur in immunocompromised patients with atypical clinical *** are no previous reports of infection by *** and Nocardia farcinica(***),especially in immunocompetent *** case report describes an immunocompetent 52-year-old woman who had overlapping infections of ***,***,and Candida parapsilosis(***)based on *** SUMMARY A 52-year-old woman presented with a productive cough and chest pain for 2 wk,and recurrent episodes of moderate-grade fever for 1 *** received antibiotics for 1 wk at a local hospital,and experienced defervescence,but the productive cough and chest pain *** collected samples of a lung lesion and alveolar lavage fluid for *** lung tissue was positive for ***,***,and ***,and the alveolar lavage fluid was positive for *** diagnosis was pneumonia,and application of appropriate antibiotic therapy cured the *** Etiological diagnosis is critical for patients with infectious *** can identify rare and novel pathogens,and does not require a priori knowledge.

关键词： Overlapping infection Mycobacterium canariasense Nocardia farcinica Metagenomic next-generation sequencing technology Case report