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Continuous-wave 2.9–3.8 μm random lasing via temperature-tunning free difference-frequency generation of random fiber lasers in PPLN crystal

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Science China(Information Sciences) 2023年第8期66卷 279-280页

作者： Bo HU Han WU Kan TIAN Houkun LIANG College of Electronics and Information Engineering Sichuan University

Continuous-wave(CW) tunable mid-infrared(MIR) laser sources are necessary for laser spectroscopy, remote sensing,and infrared imaging applications [1]. Generally, quantum cascaded lasers(QCLs) are mature MIR radiation sources with decent power. However, the tunning range of QCLs is limited to ten of cm-1. In contrast, difference-frequency generation(DFG) sources based on nonlinear optical crystals have advantages in broad wavelength tunability.

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Study on the flow field uniformity of hydro-floating ship lift combined type hydraulic-driven system based on the residual energy theory

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Journal of Hydrodynamics 2022年第6期34卷 1156-1161页

作者： bo Wu Ya-an hu Shu Xue State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan430072China State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Nanjing Hydraulic Research InstituteNanjing210029China Key Laboratory of Transport Technology in Navigation Building Construction Nanjing Hydraulic Research InstituteNanjing210029China

The hydro-floating ship lift originally invented in China is a major innovation in the field of navigation technology.The shaft water levels synchronization of its unique hydraulic-driven system plays a crucial role in reducing the torque of the synchronous shafts and ensuring the safety and stability operation of the ship lift.This study aims to investigate the muti-shaft water level synchronization and the flow velocity uniformity of the combined type hydraulic-driven system.Based on the theory of residual energy,a new index m2 proposed in this study is more suitable for evaluating the flow velocity uniformity of the combined hydraulic-driven system.Finally,the critical value of m2=75 is calculated via the results of the scaled physical mode test as the threshold of water flow uniformity,and it provides a basis for determining the reasonable height of the pressure stabilizing chamber.

关键词： Hydro-floating ship lift water levels synchronism residual energy velocity distribution uniformity coefficient

Improved Hardy–Littlewood–Sobolev Inequality on S^(n)under Constraints

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Acta Mathematica Sinica,English Series 2023年第11期39卷 2149-2163页

作者： Yun Yun hu Jing bo DOU School of Mathematics and Statistics Shaanxi Normal UniversityXi’an 710119P.R.China

In this paper,we establish an improved Hardy–Littlewood–Sobolev inequality on Snunder higher-order moments constraint.Moreover,by constructing precise test functions,using improved Hardy–Littlewood–Sobolev inequality on S^(n),we show such inequality is almost optimal in critical case.As an application,we give a simpler proof of the existence of the maximizer for conformal Hardy–Littlewood–Sobolev inequality.

关键词： Hardy–Littlewood–Sobolev inequality higher-order moments constraint concentration compactness principle almost optimal

A car-following model based on the optimized velocity and its security analysis

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Transportation Safety and Environment 2023年第4期5卷 127-134页

作者： Rong Fei Lu Yang Xinhong Hei Bo HU Aimin Li School of Computer Science and Engineering Xi’an University of TechnologyNo.5 Jinhua South RoadXi’an 710048ShaanxiP.R.China Software Design Department Hangzhou Holly Sys Automation Co.Ltd.No.29Jinye 1st RoadXi’an 710065ShaanxiP.R.China

An enhanced optimal velocity model(EOVM)that considers driving safety is established to alleviate traffic congestion and ensure driving safety.Time headway is introduced as a criterion for determining whether the car is safe.When the time headway is less discussed to ensure the model's safety and maintain the following state.A stability analysis of the model was carried out to determine than the minimum time headway(TH_(min))or more than the most comfortable time headway(TH_(com)),the acceleration constraints are the stability conditions of the model.The EOVM is compared with the optimal velocity model(OVM)and fuzzy car-following model using the real dataset.Experiments show that the EOVM model has the smallest error in average,maximum and median with the real dataset.To confirm the model's safety,design fleet simulation experiments were conducted for three actual scenarios of starting,stopping and uniform process.

关键词： optimized velocity constraint optimization security analysis

Two electron utilization of methyl viologen anolyte in nonaqueous organic redox flow battery

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Journal of Energy Chemistry 2018年第5期27卷 1326-1332页

作者： Bo HU T.Leo Liu The Department of Chemistry and Biochemistry Utah State University

Methyl viologen （MV） as a bench-mark anolyte material has been frequently applied in aqueous organic redox flow batteries （AORFBs） towards large-scale renewable energy storage. However, only the first re- duction of MV was utilized in aqueous electrolytes because of the insoluble MV0generated from the second reduction of MV. Herein, we report that methyl viologen with bis（trifluoromethane）sulfonamide counter anion, MVTFSI, can achieve two reversible reductions in a nonaqueous supporting elec- trolyte. Paired with （Ferrocenylmethyl）trimethylammonium bis（trifluoromethanesulfonyl）imide, FcNFFSI, as catholyte, the MVTFS/FcNTFSI nonaqueous organic redox flow battery （NOARFB） can take advantage of either one electron or two electron storage of the methyl viologen moiety and provide theoretical energy density of 24.9Wh/L and a cell voltage of up to 1.5V. Using a highly conductive LiTFSI/CH_3CN supporting electrolyte and a porous Daramic separator, the NOARFB displayed excellent cycling performance, includ- ing up to a 68.3g energy efficiency at 40 mA/cm2, and more than 88g total capacity retention after 100 cycles.

关键词： Redox flow battery Viologen Ferrocene Energy storage

Type Synthesis of Self-Alignment Parallel Ankle Rehabilitation Robot with Suitable Passive Degrees of Freedom

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Chinese Journal of Mechanical Engineering 2024年第1期37卷 160-175页

作者： Ya Liu Wenjuan Lu Dabao Fan Weijian Tan Bo HU Daxing Zeng School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004China School of Mechanical Engineering Dongguan University of TechnologyDongguan 523808China Dongguan Engineering Technology Research Center for Parallel Robot Dongguan 523808China The DGUT Innovation Center of Robotics and Intelligent Equipment Dongguan 523808China

The current parallel ankle rehabilitation robot(ARR)suffers from the problem of difficult real-time alignment of the human-robot joint center of rotation,which may lead to secondary injuries to the patient.This study investigates type synthesis of a parallel self-alignment ankle rehabilitation robot(PSAARR)based on the kinematic characteristics of ankle joint rotation center drift from the perspective of introducing"suitable passive degrees of freedom(DOF)"with a suitable number and form.First,the self-alignment principle of parallel ARR was proposed by deriving conditions for transforming a human-robot closed chain(HRCC)formed by an ARR and human body into a kinematic suitable constrained system and introducing conditions of"decoupled"and"less limb".Second,the relationship between the self-alignment principle and actuation wrenches(twists)of PSAARR was analyzed with the velocity Jacobian matrix as a"bridge".Subsequently,the type synthesis conditions of PSAARR were proposed.Third,a PSAARR synthesis method was proposed based on the screw theory and type of PSAARR synthesis conducted.Finally,an HRCC kinematic model was established to verify the self-alignment capability of the PSAARR.In this study,93 types of PSAARR limb structures were synthesized and the self-alignment capability of a human-robot joint axis was verified through kinematic analysis,which provides a theoretical basis for the design of such an ARR.

关键词： Ankle rehabilitation robot Self-alignment Parallel mechanism Type synthesis Screw theory

Study on 6-DOF active vibration-isolation system of the ultra-precision turning lathe based on GA-BP-PID control for dynamic loads

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Advances in Manufacturing 2024年第1期12卷 33-60页

作者： bo Wang Zhong Jiang Pei-Da hu Department of Precision Instrument Tsinghua UniversityBeijing100084People’s Republic of China Institute of Machinery Manufacturing Technology China Academy of Engineering PhysicsMianyang621900SichuanPeople’s Republic of China

The vibration disturbance from an external environment affects the machining accuracy of ultra-precision machining equipment.Most active vibration-isolation systems(AVIS)have been developed based on static loads.When a vibration-isolation load changes dynamically during ultra-precision turning lathe machining,the system parameters change,and the efficiency of the active vibration-isolation system based on the traditional control strategy deteriorates.To solve this problem,this paper proposes a vibration-isolation control strategy based on a genetic algorithm-back propagation neural network-PID control(GA-BP-PID),which can automatically adjust the control parameters according to the machining conditions.Vibration-isolation simulations and experiments based on passive vibration isolation,a PID algorithm,and the GA-BP-PID algorithm under dynamic load machining conditions were conducted.The experimental results demonstrated that the active vibration-isolation control strategy designed in this study could effectively attenuate vibration disturbances in the external environment under dynamic load conditions.This design is reasonable and feasible.

关键词： Ultra-precision diamond turning lathe Active vibration isolation Six degrees of freedom Dynamic load Genetic algorithm-back propagation neural network-PID(GA-BP-PID)control

Insight on corrosion behavior of a Cu-P-Cr-Ni steel with different Ni contents by electrochemical and periodic immersion corrosion experiments

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Journal of Iron and Steel Research(International) 2023年第3期30卷 580-590页

作者： Zhi-wei Lian Tian-en Peng Shuang hu bo He Xue-wen hu Tao Zhu bo Jiang School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China Technical Center Ma’anshan Iron&Steel Co.Ltd.Ma’anshan 243041AnhuiChina

Corrosion behavior of Cu-P-Cr-Ni weathering steels with different nickel contents was studied by periodic immersion corrosion test for 72 h.The mass loss method was used to evaluate the weatherability of weathering steel.The rust layers formed on weathering steel were characterized by scanning electron microscopy,X-ray diffraction,electron probe microanalysis,X-ray photoelectron spectroscopy,and electrochemical measurements.The results of periodic immersion corrosion test for 72 h showed that the mass loss rates of Cu-P-Cr-0.14Ni steel and Cu-P-Cr-0.04Ni steel were 1.57 and 1.61 g/(m^(2)h),respectively.According to the electrochemical experiment,the corrosion potentials of the two tested steels at the initial stage of corrosion were-0.6852 and-0.7037 V,respectively.With the corrosion time reaching 72 h,the corrosion potential difference between the two tested steels was gradually reduced.In the initial stage,NiO was formed in the rust layer and can dramatically promote the crystallization of corrosion products to improve the stability of the rust layer.After periodic immersion corrosion test for 72 h,Ni element had no obvious effect.At this time,it was mainly the enrichment of Cu and Cr elements in the form of CuO and Cr_(2)O_(3)in the rust layer that could further protect the matrix.

关键词： Weathering steel Ni Electrochemical experiment Periodic immersion corrosion Corrosion behavior

A hot tearing criterion based on solidifcation microstructure in cast alloys

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Journal of Materials Science & Technology 2022年第10期105卷 68-80页

作者： Bo HU Zixin Li Dejiang Li Tao Ying Xiaoqin Zeng Wenjiang Ding National Engineering Research Center of Light Alloy Net Forming School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China The State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240China

A criterion based on solidifcation microstructure was proposed to precisely predict the hot tearing behavior of cast alloys,which takes into account the effects of both mechanical and nonmechanical factors.This criterion focuses on the events occurring at the grain boundary,which are determined by the thermal contraction,solidifcation shrinkage,grain growing and liquid feeding.This criterion responds to a series of factors that affect hot tearing,such as alloy composition,mold design,casting process and microstructure.Its credibility has been validated by studying the hot tearing behavior of Mg-Ce alloys.In conformity with the experimental results,this criterion predicted decrease in the number of rods occurring hot tearing with increasing cerium content.A simplifed criterion was derived and validated by Mg-Ce(equiaxed grain)and Mg-Al(columnar grain)alloy systems,which is suitable for the case where the eutectic liquid fraction is low and the liquid feeding can be ignored.In addition,a hot tearing index for equiaxed grains was proposed,that is,|d T/d(f_(s)^(1/3)near(f_(s))^(1/3)=1,and its prediction results were consistent with the hot tearing susceptibility calculated from the experimental results.

关键词： Hot tearing Microstructure Magnesium alloys Casting Criterion