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fast efficient photon deceleration in plasmas by using two laser pulses at different frequencies

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matter and Radiation at Extremes 2024年第3期9卷 11-18页

作者： Y.X.Wang X.L.Zhu S.m.Weng P.Li X.F.Li H.Ai H.R.Pan Z.m.Sheng Key Laboratory for Laser Plasmas(moe) School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Center of IFSA Shanghai Jiao Tong UniversityShanghai 200240China Research Center of Laser Fusion of China Academy of Engineering Physics MianyangSichuan 621900China State key Laboratory of High Field Laser Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China Tsung-dao Lee Institute Shanghai Jiao Tong UniversityShanghai 200240China

The generation of ultrashort high-power light sources in the mid-infrared(mid-ir)to terahertz(THz)range is of interest for applications in a number of fields,from fundamental research to biology and *** conventional laser technology,photon deceleration in plasma wakes provides an alternative approach to the generation of ultrashort mid-ir or THz ***,we present a photon deceleration scheme for the efficient generation of ultrashort mid-ir or THz pulses by using an intense driver laser pulse with a relatively short wavelength and a signal laser pulse with a relatively long *** signal pulse trails the driver pulse with an appropriate time delay such that it sits at the front of the second wake bubble that is driven by the driver *** to its relatively long wavelength,the signal pulse will be subjected to a large gradient of the refractive index in the plasma wake ***,the photon deceleration in the plasma wake becomes faster and more efficient for signal pulses with longer *** greatly enhances the capacity and efficiency of photon deceleration in the generation of ultrashort high-power light sources in the long-wavelength ir and THz spectral ranges.

关键词： laser ultrashort photon

Experimental investigations on small-and full-scale ship models with polyurea coatings subjected to underwater explosion

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Defence Technology（防务技术） 2022年第7期18卷 1257-1268页

作者： Jian Liu Feng-jiang An Cheng Wu sha-sha Liao ming-xue Zhou Dong-yu Xue Huan Guo State Key Laboratory Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China

Nowadays, the mitigation of damage to a ship caused by the underwater explosion attracts more and more attention from the modern ship designers. In this study, two kinds of scale tests were conducted to investigate the effects of polyurea coatings on the blast resistance of hulls subjected to underwater explosion. Firstly, small-scale model tests with different polyurea coatings were carried out. Results indicate that polyurea has a better blast resistance performance when coated on the front face, which can effectively reduce the maximum deflection of the steel plate by more than 20% and reduce the deformation energy by 35.7%-45.4%. Next, a full-scale ship(approximately 50 m × 9 m) under loadings produced by the detonation of 33 kg of spherical TNT charges was tested, where a part of the ship was coated with polyurea on the front face(8 mm + 24 mm) and not on the contrast area. Damage characteristics on the bottom were statistically analyzed based on a 3D scanning technology, indicating that polyurea contributes to enhancing the blast protection of the ship. However, damage results of this test were different from those of the small-scale tests. moreover, the deformation area of the bottom with polyurea was greatly increased by 40.1% to disperse explosion energy, a conclusion that cannot be drown from the small-scale tests.

关键词： Polyurea coatings Small-scale model Full-scale ship Underwater explosion Blast resistance

EXPERImENTAL RESEARCH AND NUmERICAL SImULATION OF mOLD TEmPERATURE FIELD IN CONTINUOUS CASTING OF STEEL

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Acta metallurgica Sinica(English Letters) 2006年第3期19卷 176-182页

作者： X.S. Zheng m.H. sha J.Z. Jin Research Center of Foundry Engineering Dnlian University of Technology Dalian 116024 China School of materials Science and Engineering Anshan University of Science and Technology Anshan 114044 China

mold is the heart of the continuous casting machine. Heat transfer and solidification in a water- cooled mold are the most important factors during the continuous casting of steel. For studying the temperature distribution of a mold wall, a simulated apparatus of mold was designed and experiments were performed by it. The measured results indicated that the mold wall temperature approaches the temperature of cooling-water. An equivalent thermal-conductivity coefficient was proposed and deduced on the basis of the conclusion of the experiments. This coefficient was applied to solve the heat transfer between the melt and cooling water, and to characterize the heat transfer capacity of the mold. By this equivalent thermal-conductivity coefficient, it is very easy and convenient to numerically simulate the solidification process of continuous casting. And the calculation results are in agreement with the experiments. The effects of custing speed and water flow rate on the mold temperature field were also discussed.

关键词： continuous casting mold temperature field numerical simulation

Relative contributions of temperature and salinity to steric sea level over the South China Sea

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Journal of Oceanology and Limnology 2022年第2期40卷 428-437页

作者： Jin sha Xiaoming LI Xiaohai YAN Key Laboratory of Digital Earth Science Aerospace Information Research InstituteChinese Academy of SciencesBeijing 100094China Hainan Key Laboratory of Earth Observation Sanya 502022China Center for Remote Sensing College of EarthOcean and EnvironmentUniversity of DelawareNewark 19711DEUSA Joint Institute for Coastal Research and management University of Delaware/Xiamen UniversityUSA/China

The relative contributions of surface temperature and salinity to steric sea-level variations are investigated using satellite observations and reanalysis *** defi ning a contribution factor,the relative roles of thermal and haline steric height variations are quantifi ed over the South China Sea(SCS).The thermosteric height dominates the steric sea level variation in the northern SCS deep basin,while the contribution of the halosteric height increases *** investigation reveals that this transition is related to the meridional imbalance of surface heat flux and precipitation *** revealed steric constitution distribution is not confi ned to the surface but extends within the upper layer to approximately 50m depth,and then the thermosteric component dominates from the depth *** results of this study clarify the steric sea level constitution over the SCS,benefit the understanding of sea-level variations at the regional scale,and may further facilitate multisensor remote sensing data mining studies.

关键词： South China Sea(SCS) steric height steric constitution

Sediment resuspension under action of wind in Taihu Lake,China

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International Journal of Sediment Research 2015年第1期30卷 48-62页

作者： sha-sha ZHENG Pei-fang WANG Chao WANG Jun HOU Key Laboratory of Integrated Regulation and Resource Department on shallow Lakes Ministry of EducationCollege of EnvironmentHohai University College of Environment Hohai University

A field study was undertaken to investigate the changes of the current speed,wave parameters and sediment resuspension under different wind speeds in the Taihu *** Acoustic Doppler Current Profiler(ADCP) and mIDAS DWR Wave Recorder were used to collect the data of currents and waves,*** characteristics of sediment resuspension were investigated by a layered sampling *** measurement results showed that the current speed increased in direct proportion with the wind *** distributions of the current speed represented significant inflection points at 0.4 of the relative water *** the upper and lower layers followed logarithmic *** mean wind speed and wave parameters(wave height and wave energy density) showed exponential distributions,meanwhile similar distribution was found between the mean wind speed and current *** rising surface wind,a corresponding increase in the concentration and particle size of the Suspended Particulate matter(SPm) was observed in the water *** kinds of particles could influence the SPm concentration in the water *** critical wind speed of sediment resuspension and the corresponding sediment incipient shear stress was found to be 3.7-4.0 m s-1and 0.011 N m-2,*** results of this study can be used to help understand and predict the changes of flow structure and water quality induced by different wind disturbances in shallow lakes.

关键词： Wind disturbance Current Wave Sediment resuspension Taihu Lake

A Study on Quasi-orthogonal m-ary Chirp modulation

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Chinese Journal of Electronics 2019年第5期28卷 1053-1058页

作者： YANG Liu ZHANG fangqi ZHENG Guoxin sha Jiajun Key Laboratory of Specialty Fiber Optics and Optical Access Networks Joint International Research Laboratory of Specialty Fiber Optics and Advanced Communication Shanghai Institute for Advanced Communication and Data ScienceShanghai University School of Electronic and Information Shanghai Dianji University maglev Transportation Engineering R&D Center The Key Laboratory of Road and Traffic Engineering Ministry of Education Tongji University

This paper proposes and studies a novel m-ary chirp modulation scheme adopting quasi-orthogonal waveforms. The Symbol error probability(SEP) of m-ary modulation over Additive white Gaussian noise(AWGN)channel is derived based on coherent detection, which is a function of modulation factor and waveform ***, the SEP is investigated over a channel limited by a nominal bandwidth. Both theoretical analysis and simulations prove that the SEP performance of the proposed 8-ary chirp modulation outperforms that of conventional 8 Phase shift keying(8PSK) with the same bandwidth efficiency.

关键词： Chirp modulation Correlation coefficient Quasi-orthogonal waveform

microstructure and wear behavior of mo–60Si–5B coating doped with 0.5 at% La by spark plasma sintering

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Progress in Natural Science:materials International 2022年第6期32卷 752-757页

作者： Zilong Wu Kanglu Feng Jiangbo sha Chungen Zhou School of materials Science and Engineering Beihang University

mo-60Si-5B coating doped with 0.5 at% La was prepared on niobium silicon based alloy by spark plasma *** microstructure and wear behavior of the 0.5La-mo-60Si-5B（0.5La-mSB） coating were *** results show that the mean grain sizes of the mo-60Si-5B（0La-mSB） and 0.5La-mSB coatings are calculated to be 3.27 μm and 2.85 μm,*** addition of La plays a role of refining the grains of 0.5La-mSB *** specific wear rate of 0.5La-mSB coating is decreased by up to 26.8% at the oscillation frequency of 20 Hz and the sliding load of 11 N compared to 0La-mSB *** anti-friction performance of mo-60Si-5B coating is modified by the addition of 0.5 at.% *** improvement of anti-friction performance of the mo-60Si-5B coating is due to the increased hardness and the provided lubrication function by La2O3.

关键词： metal coatings La 2 O 3 Nanoindentation Wear behavior

Cellular automata simulation of grain growth of powder metallurgy Ni-based superalloy

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Journal of iron and Steel Research International 2023年第4期30卷 838-848页

作者： Yi-ling Jiang sha-sha Liu Rong-gui Lu Xu Cheng Jia Li Yang Chen Gao-feng Tian School of materials Science and Engineering Beihang UniversityBeijing 100191China National Engineering Laboratory of Additive manufacturing for Large metallic Components Beijing 100191China Beijing Institute of Aeronautical materials Beijing 100095China

Primary γ'phase instead of carbides and borides plays an important role in suppressing grain growth during solution at 1433 K of Ni-based FGH98 *** illustrate that as-fabricated FGH98 superalloy has equiaxed grain structure,and after heat treatment,grains remain equiaxed but grow *** order to clarify the effects of the size and volume fraction of the primaryγ'phase on the grain growth during heat treatment,a 2D cellular automata(CA)model was established based on the thermal activation and the lowest energy *** CA results are compared with the experimental results and show a good fit with an error less than 10%.Grain growth kinetics are depicted,and simulations in real time for various sizes and volume fractions of primaryγ'particles work out well with the Zener *** coefficient n value which reflects the pinning ability in Zener relation is theoretically calculated,and its minimum value is 0.23 when the radius of primaryγ'phase is 2.8μm.

关键词： Grain growth Cellular automata Ni-based FGH98 superalloy Primary γ'phase microstructure

CATH-B1抑制肠外致病性大肠杆菌诱导小胶质细胞炎性反应的作用研究

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微生物学报 2024年第7期64卷 2381-2393页

作者：许雅婷潘言迪徐刘溢方仁东江莎彭练慈西南大学动物医学院重庆400715

【目的】探究抗菌肽CATH-B1对肠外致病性大肠杆菌RS218感染诱导小胶质细胞(BV2细胞)炎症反应的影响及作用机制。【方法】使用RS218感染小胶质细胞作为炎症模型,试验分为mock组、RS218感染组和CATH-B1预处理+RS218感染组。采用Cell Count... 详细信息

【目的】探究抗菌肽CATH-B1对肠外致病性大肠杆菌RS218感染诱导小胶质细胞(BV2细胞)炎症反应的影响及作用机制。【方法】使用RS218感染小胶质细胞作为炎症模型,试验分为mock组、RS218感染组和CATH-B1预处理+RS218感染组。采用Cell Counting Kit-8(CCK8)试剂盒检测细胞活力,通过菌落计数法检测CATH-B1对细菌生长的影响和细菌的黏附入侵,酶联免疫吸附测定法检测炎症因子白细胞介素(interleukin,IL)-1β、IL-6、IL-12和肿瘤坏死因子-α(tumor necrosis factorα,TNF-α)含量,实时荧光定量PCR(quantitative real-time PCR,RT-PCR)检测IL-1β和IL-6 m RNA表达水平,蛋白质印迹分析(Western blotting)法检测细胞中转录因子蛋白家族核因子κB(nuclear factor kappa-B,NF-κB)P65和P-P65、丝裂原活化蛋白激酶(mitogen-activated protein kinase,mAPK)ERK和P-ERK的蛋白表达水平。【结果】CATH-B1显著降低了RS218诱导的促炎细胞因子IL-1β、IL-6和IL-12的水平,同时显著抑制IL-1β和IL-6 m RNA表达,尽管CATH-B1对细菌的黏附入侵无显著影响,但CATH-B1能够显著抑制P65和ERK磷酸化蛋白的表达。【结论】CATH-B1通过抑制NF-κB和mAPK信号通路的活化来发挥抑制炎症作用,为阐明抗菌肽抗神经炎症机制提供了重要依据。

关键词： CATH-B1 肠外致病性大肠杆菌小胶质细胞炎症 NF-κB/mAPK信号通路