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Experimental Study on Effect of Inclination Angle on Bubble Collapse near Attached Air Bubble

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China Ocean Engineering 2023年第5期37卷 753-767页

作者： WANG Jia-xia WU Shi-zeng liU Kun JIANG ming-zuo WANG Zi-li School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China College of Automation Jiangsu University of Science and TechnologyZhenjiangJiangsu 212003China

Experiments were conducted to investigate the dynamics of an oscillating bubble generated by a spark in the presence of an inclined attached air *** study primarily focused on the influence of the inclination angle on the behavior of bubble jetting orientation,air bubble shape modes,and motion characteristics of the interaction between the two *** complex bubble jetting behaviors were observed,including the presence of multiple types of bubble jetting directions,bubble splitting,and multidirectional *** types of air bubble shapes were defined,namely inclined cup cover-shaped(with and without splitting),double-peaked cup cover-shaped,and inclined L-shaped air *** formation of different types of bubble jets was analyzed using the vector synthesis principle of the Bjerknes force exerted by the inclined attached air bubble and a steel *** describe the diverse orientations of bubble jetting and air bubble shapes,new parameters namely the dimensionless spark bubble oscillation time T^(*)and volume ratio V^(*)that consider the inclination angle are *** findings of this investigation contribute to the existing knowledge and have the potential to further enhance methods for mitigating cavitation damage in marine,hydraulic machinery systems,and medical fields.l fields.

关键词： spark-generated bubble experiment inclination angle bubble jet air bubble shape bubble dynamics

An innovative method for calibrating local cooling rate in electroslag remelting of M42 high-speed steel

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Journal of Iron and Steel Research International 2021年第8期28卷 990-996页

作者： Wan-ming li Shi-chao Jiao Wen-jie Tong Xi-min Zang De-jun li Zhou-hua Jiang Hua-bing li Yu-an Jing School of Material and Metallurgy University of Science and Technology LiaoningAnshan 114051LiaoningChina State Key Laboratory of Marine Engineering Anshan 114051LiaoningChina School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina

The determination of the local cooling rate has a great significance in optimizing the parameters of electroslag remelting(ESR)and improving the quality of the *** innovative method was proposed for calibrating the local cooling rate of M42 high-speed steel(HSS)in the ESR *** resolidification at different cooling rates under high-temperature laser confocal microscopy,the carbide network spacing of the specimen was observed using a scanning electron microscope.A functional relationship between the cooling rate and average carbide network spacing was *** average local cooling rate of the solidification process of the M42 HSS ingot was *** results show that the higher the cool-ing rate,the smaller the network spacing of the *** the steel ingot with a diameter of 360 mm,the average local cooling rate was 0.562℃/s at the surface,0.057℃/s at the position of 0.25D(where D is the diameter of the ingot),and 0.046℃/s at the center of the ingot.

关键词： Cooling rate Electroslag remelting Carbide Network spacing Calibrating High-speed steel

Semisolid Slurry Preparation of Die Steel with High Chromium Content

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Journal of Iron and Steel Research International 2004年第5期11卷 8-12页

作者： MAO Wei-min ZHAO Ai-min ZHANG li-juan ZHONG xue-you University of Science and Technology Beijing

The control model of laminar cooling system for hot strip, including air-cooling model, water-cooling model, temperature distribution model along thickness direction, feedforward control model, feedback control model and self-learning model, was introduced. PID arithmetic and Smith predictor controller were applied to feedback control. The sample of model parameter classification was given. The calculation process was shown by flow chart. The model has been proved to be simple, effective and of high precision.

关键词： hot strip laminar cooling control model Smith predictor

Highly Efficient Removal of Organic Dyes by Novel As-synthesized AgBr/montmorillonite Composite

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Journal of Wuhan University of Technology(Materials Science) 2019年第1期34卷 35-40页

作者： Lü Jianchang GE ming College of Chemical Engineering North China University of Science and Technology Hebei Key Laboratory of Photocatalytic and Electrocatalytic Materials for Environment

A facile deposition method has been developed for large-scale synthesis of visible-light-driven AgBr/montmorillonite composite catalyst for the first time. The as-synthesized samples were characterized by X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), Fourier transform infrared spectroscopy(FT-IR), transmission electron microscopy(TEM), UV-vis diffuse reflectance spectroscopy(UV-vis DRS) and Brunauer-Emmett-Teller(BET) surface area analysis, respectively. Through the combined action of adsorption and photodegradation, the as-prepared AgBr/montmorillonite composite exhibited a higher removal efficiency for rhodamine B(RhB) than that of Na-montmorillonite and AgBr. For the methyl orange(MO) removal, the AgBr/montmorillonite composite possessed a superior photocatalytic performance compared with Namontmorillonite and AgBr. The enhanced photocatalytic activity of AgBr/montmorillonite composite can be attributed to the effective separation of the electron-hole pairs. In AgBr/montmorillonite suspension, the superoxide radicals are the main reactive oxygen species for dye degradation under visible light illumination.

关键词： AgBr/montmorillonite adsorption photocatalysis dye photocatalytic mechanism

Status and path of intergenerational transmission of poverty in rural China:A human capital investment perspective

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Journal of Integrative Agriculture 2021年第4期20卷 1080-1091页

作者： BAI Yun-li ZHANG lin-xiu SUN ming-xing XU Xiang-bo Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101P.R.China UN Environment Programme-International Ecosystem Management Partnership Beijing 100101P.R.China

This paper focused on the intergenerational transmission of poverty in rural China by estimating the intergenerational transmission of earnings and stated its mechanism from the perspective of human capital investment before children participated in the labor *** data used in this study were longitude data collected in 2000 households of 100 villages among 25 counties across five provinces in 2005,2008,2012,2016,and *** and quantitative methods were *** found a significant intergenerational transmission of earnings in rural China,especially for the pairs of father–children and parents–*** intergenerational earnings'elasticities were much less than those in urban areas,which indicated better social mobility in rural areas than that in urban *** children with parents who could earn much were more likely to be invested before they participated in the labor market,gain a high education and have more *** cases further showed that the mechanism of human capital investment in children breaking the intergenerational transmission of poverty and promoting social mobility.

关键词： poverty intergenerational transmission human capital rural China

Strain-controlled fatigue characteristics of a cast Mg-Nd-Zn under peak-aged and over-aged conditions

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Rare Metals 2023年第7期42卷 2381-2389页

作者： Zhen-ming li Ji-Chun Dai Bao-liang liu Hui Zou Ji-Peng Pan Institute of Sci-technology Strategy Jiangxi Academy of SciencesNanchang330096China Zhejiang Jinfei Kaida Wheel Co. LtdJinhua321000China Research Institute(R&D Center) Shanghai JuneBang Technology CorporationShanghai200032China National Engineering Research Center of light Alloy Net Forming Shanghai200240China National Engineering Research Center of light Alloy Net Forming Shanghai Jiao Tong UniversityShanghai200240China

Strain-controlled fatigue characteristics of peakaged and over-aged Mg_(96.47)Nd_(2.9)Zn_(0.21)magnesium alloys containing 0.42Zr,including stress response,strain resistance,hysteresis loops,strain-life and corresponding lowcycle fatigue life prediction model,were *** the peak-aged state(T61:540℃×8 h+200℃×14 h),the alloy shows higher cyclic stress response,but lower ductility than the alloy in the over-aged state(T6_(2):540℃×8 h+200℃×400 h).The yield strength and ultimate tensile strength of the alloy under T6_(1)-and T6_(2)-treated conditions are *** with T6_(1)-treated alloy,the steady stress amplitude occurred in T6_(2)-treated alloy is due to higher ductility and more homogenous *** T6_(1)state,the fatigue cracks in the alloy first initiate along the cracked persistent slip bands and then propagate in the trans-granular mode,while in the T6_(2)state,the fatigue cracks initiate along grain boundaries and then propagate in the inter-granular mode.

关键词： Mg-Nd-Zn alloy Strain-controlled fatigue Peak-aged and over-aged conditions Hysteresis energy

Angular disturbance prediction for countermeasure launcher in active protection system of moving armored vehicle based on an ensemble learning method

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Defence Technology（防务技术） 2023年第3期21卷 207-218页

作者： Chun-ming li Guang-hui Wang Hai-ping Song Xu-feng Huang Qi Zhou China North Vehicle Research Institute Beijing100072China School of Aerospace Engineering Huazhong Univerisity of Science and TechnologyWuhan430074China

The active protection system(APS),usually installed on the turret of armored vehicles,can significantly improve the vehicles’survivability on the battlefield by launching countermeasure munitions to actively intercept incoming ***,uncertainty over the launch angle of the countermeasure is increased due to angular disturbances when the off-road armored vehicle is moving over rough ***,accurate and comprehensive angular disturbance prediction is essential to the real-time monitoring of the countermeasure launch *** this paper,a deep ensemble learning(DEL)-based approach is proposed to predict the angular disturbances of the countermeasure launcher in the APS based on previous time-series *** view of the intricate temporal attribute of angular disturbance prediction,the sampling information of historical time series measured by an inertial navigation device is adopted as the input of the developed DEL ***,the recursive multi-step(RMS)prediction strategy and multi-output(MO)prediction strategy are combined with the DEL model to perform the final angular disturbance prediction for the countermeasure launcher in the APS of a moving armored *** proposed DEL model is validated by using the different datasets from real *** results reveal that this approach can be used to accurately predict angular disturbances,with the maximum absolute error of each DOF less than 0.1°.

关键词： prediction disturbance moving

Super-High Initial Velocity Mechanism of Bullet Propulsion with Adaptive Pressure-Maintaining Chamber

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Journal of Beijing Institute of Technology 2020年第1期29卷 23-28页

作者： Junbo Xiao Hongqiang li Zhenqiang liao ming Qiu Jie Song School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China

To deal with the problem that the initial velocity of the bullet is difficult to increase,the research on the super-high initial velocity propulsion in the barrel weapon with an adaptive pressure-maintaining chamber are *** the law of gun-powder burning and the flow characteristics of gun-powder gas in multi-chamber,the scheme of super-high initial velocity propulsion with an adaptive pressure-maintaining chamber is designed,the ballistic model of the barrel weapon with super-high velocity bullet propulsion is *** research results show that the technical scheme can greatly increase the initial velocity of the bullet with the peak pressure keeping nearly the same as the tradition barrel *** research results can provide a theoretical foundation to significantly increase the initial velocity in barrel weapons using solid propellants,and have an important reference value to comprehensively increase the power of the barrel weapons.

关键词： inner trajectory adaptive pressure-maintaining chamber super-high initial velocity propulsion barrel weapon

Distinctive Polymorphism-like Isodimorphism in Poly(propylene succinate-ran-propylene fumarate)

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Chinese Journal of Polymer Science 2022年第6期40卷 602-610页

作者： xue-Wei Wei Xin-Xin Zhao Yi li Xiao-Yu Meng Qiong Zhou Hai-Mu Ye Department of Materials Science and Engineering College of New Energy and MaterialsChina University of PetroleumBeijing 102249China

Co-crystallization of different monomeric units fundamentally contributes to the versatile and tunable performance of random *** present,the crystallization manners of random binary copolymers have been divided into three categories:isomorphism,isodimorphism and comonomer *** category,however,has its own advantages and ***,it is challenging to design and prepare random copolymer sharing the advantages of isomorphism and isodimorphism through a new co-crystallization manner beyond the ones already *** the basis of previous study on poly(alkylene succinate-ran-alkylene fumarate)whose co-crystallization can be extensively and finely regulated by simply varying the chemical structure of alkylene,random copolymers of poly(propylene succinate-ranpropylene fumarate)(PPSF)are synthesized using 1,3-propanediol as the diol *** thermal properties and crystal structure of PPSF are investigated,and,intriguingly,it is proved that PPSF is an isodimorphism system while displays similar composition-dependent thermal properties and crystallinity as *** is,PPSF exhibits a novel co-crystallization behavior that has rarely been discovered,which would combine the advantages of both isomorphism and ***,PPSF could be termed as a new-type,special compositiondependent ***,the altering of PPS-like to PPF-like crystal structure of PPSF when changing chain composition has been proved to originate from the shift of dominant inter-segment interaction from van der Waals forces to strong hydrogen-bonding *** work enriches the co-crystallization manner of random copolymers,leading to more diverse performance design of polymer materials.

关键词： Co-crystallization Random copolymer Isodimorphism Inter-segment interaction