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Experimental Investigation on Thermal Characteristics of Long Distance Loop Heat Pipes

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Journal of Thermal Science 2022年第3期31卷 741-750页

作者： ZHAO Ya’nan YAN tao LIANG Jingtao Key Laboratory of Space Energy Conversion Technology Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100190China

Loop heat pipes(LHPs)are attractive two-phase thermal control devices for satellites,electronics and many other applications.They are capable of transporting heat efficiently for long distances up to several meters at any orientation.This paper investigated the heat transfer characteristics of loop heat pipes with long distances and small diameter transport lines.Small stainless steel tubes of 2 mm and 3 mm in inner diameters were chosen as liquid lines and vapor lines of the LHPs.The local thermal resistances in the evaporator of the 6 m-LHP were researched and analyzed,which indicated that the thermal resistance between the aluminum block and the vapor in the vapor channel accounted for a major proportion of the total thermal resistance.The effect of heat sink temperatures on the performance of the 6 m-LHP were compared with 10°C,15°C,20°C and 25°C cooling water temperatures.Moreover,the thermal characteristics of LHPs with transport distances of 2 m and 16 m were also experimentally investigated.The 16 m-LHP could achieve a heat transfer capacity of 100 W and the 2 m-LHP could reach more than 339 W,on the premise of the evaporator temperature below 100°C.The thermal resistance of the 2 m-LHP could achieve 0.125°C/W.

关键词： loop heat pipe thermal management heat transport long distance thermal resistance

Experimental Study on Cooling Down Process of a Nitrogen-Charged Cryogenic Loop Heat Pipe

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Journal of Thermal Science 2023年第1期32卷 153-165页

作者： ZHAO Ya'nan YAN tao LIANG Jingtao Key Laboratory of Space Energy Conversion Technology Technical Institute of Physics and ChemistryChinese Academyof SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

Cryogenic loop heat pipes are highly efficient heat transfer devices at cryogenic temperature range,which have promising application prospects in satellites,spacecrafts,electronics,and so on.Cooling down process is a most critical process for a CLHP before startup.At present,secondary loop is a major way for a CLHP to fulfil cooling down and most studies are concentrated on heat transfer characteristics during normal operation.However,few investigations have been carried out on the cooling down process.In this paper,the cooling down process of a nitrogen-charged CLHP assisted with a secondary loop was experimentally investigated.A simple qualitative approach to estimate the cooling down time was proposed according to the law of conservation of energy.The two flow paths of the working fluid in the CLHP during the cooling down process were described.Experimental studies on the cooling down process with various secondary heat loads and working fluid inventory were presented in detail.With the increase of secondary heat load,the elapsed time of Stage III decreased significantly due to the larger mass flow rate in Path I.In addition,the effect of the working fluid inventory on the cooling down time was generally small in the range from 2.99 MPa to 3.80 MPa.However,with 2.80 MPa working fluid inventory,it required much longer cooling down time,which was because of the lack of liquid in the CLHP with low working fluid inventory.Moreover,the influence of gravity on the temperature variation of the components during the experiments was analyzed.This work is beneficial for better understanding of the cooling down process and optimizing of CLHPs.

关键词： cryogenic loop heat pipe secondary loop cooling down heat transfer

Quantum-Behaved Particle Swarm Optimization Algorithm Based on the Two-Body Problem

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Chinese Journal of Electronics 2019年第3期28卷 569-576页

作者： YAN tao LIU Fengxian Institute of Big Data Science and Industry Shanxi University School of Computer and Information Technology Shanxi University Key Laboratory of Computational Intelligence and Chinese Information Processing of Ministry of Education Guangzhou Institute of Electronic Technology Chinese Academy of Sciences University of Chinese Academy of Sciences

The present study proposes an improved Quantum-behaved particle swarm optimization algorithm based on the two-body problem model(QTPSO) for solving the problem that other quantum-behaved particle swarm optimization algorithms easily converge on local optimal solutions when solving complex nonlinear problems. In the proposed QTPSO algorithm, particles are categorised as core particles and edge particles. Once the position of the core particle is determined, the edge particle appears in the vicinity of the attractor exhibiting a high probability, and the attractor is obtained through the random weighted sum of the core particle and the optimal mean position. Through simulation of the motion of these two particles by applying the interaction of the particles in the two-body problem, this mechanism not only improves the diversity of the population, but also enhances the local search capacity. To validate the proposed algorithm, three groups of experimental results were obtained to compare the proposed algorithm with other swarm intelligence algorithms. The experimental results indicate the superiority of the QTPSO algorithm.

关键词： Quantum-behaved particle swarm optimization Two-body problem Quantum potential well Wave function Nonlinear optimization problems

Real-Time Control Strategy of Exoskeleton Locomotion Trajectory Based on Multi-modal Fusion

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Journal of Bionic Engineering 2023年第6期20卷 2670-2682页

作者： tao Zhen Lei yan College of Engineering Beijing Forestry UniversityNo.35East Qinghua RoadBeijing100083China

The exoskeleton robot is a typical man–machine integration system in the human loop.The ideal man–machine state is to achieve motion coordination,stable output,strong personalization,and reduce man–machine confrontation during motion.In order to achieve an ideal man–machine state,a Time-varying Adaptive Gait Trajectory Generator(TAGT)is designed to estimate the motion intention of the wearer and generate a personalized gait trajectory.TAGT can enhance the hybrid intelligent decision-making ability under human–machine collaboration,promote good motion coordination between the exoskeleton and the wearer,and reduce metabolic consumption.An important feature of this controller is that it utilizes a multi-layer control strategy to provide locomotion assistance to the wearer,while allowing the user to control the gait trajectory based on human–robot Interaction(HRI)force and locomotion information.In this article,a Temporal Convolutional Gait Prediction(TCGP)model is designed to learn the personalized gait trajectory of the wearer,and the control performance of the model is further improved by fusing the predefined gait trajectory method with an adaptive interactive force control model.A human-in-the-loop control strategy is formed with the feedback information to stabilize the motion trajectory of the output joints and update the system state in real time based on the feedback from the inertial and interactive force signal.The experimental study employs able-bodied subjects wearing the exoskeleton for motion trajectory control to evaluate the performance of the proposed TAGT model in online adjustments.Data from these evaluations demonstrate that the controller TAGT has good motor coordination and can satisfy the subject to control the motor within a certain range according to the walking habit,guaranteeing the stability of the closed-loop system.

关键词： Exoskeleton Multi-layer control strategy Human–machine collaboration Time-varying adaptive gait Hybrid intelligent

Preparation of B_(2)O_(3)/SBA-15 and Application as Matrix Component in Nickel-Tolerant Fluid Catalytic Cracking Catalyst

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China Petroleum Processing & Petrochemical Technology 2023年第1期25卷 144-150页

作者： Yuan Chengyuan Ju Guannan Chen Qiang YAN tao Li Zhongfu School of Materials Science and Engineering Shandong University of TechnologyZiboShandong 255000China Shanxi Tengmao Technology Co. Ltd.HejinShanxi 043300China

Fluid catalytic cracking(FCC)is still a key process in the modern refining industry,in which nickel contamination of the FCC catalyst can significantly increase the dry gas and coke yields and thus seriously affect the stability of the FCC unit.Therefore,in this work,B_(2)O_(3)-modified SBA-15 molecular sieves(B_(2)O_(3)/SBA-15)with different B_(2)O_(3) contents were prepared,characterized,and further used as matrix component in the preparation of Ni-tolerant FCC catalyst.The characterization results indicated that the B_(2)O_(3)/SBA-15 samples possessed excellent Ni passivation ability and kept the characteristic structure of the parent SBA-15 such as highly ordered mesopores,large surface area,and high pore volume,which enabled the B_(2)O_(3)/SBA-15 sample to greatly improve the Ni tolerance of the prepared FCC catalyst.The heavy oil catalytic cracking tests indicated that,under the same Ni contamination conditions,the dry gas,coke,and heavy oil yields of the FCC catalyst containing B_(2)O_(3)/SBA-15 decreased by 0.92%,1.65%,and 1.26%,respectively,compared with those of conventional FCC catalyst,while the total liquid yield increased by 3.83%.

关键词： Ni tolerance B_(2)O_(3)modification SBA-15 FCC catalyst

Structural characterization,in vivo toxicity and biological activity of two new pyro-type diterpenoid alkaloids derived from 3-acetylaconitine

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Journal of Integrative Medicine 2023年第3期21卷 302-314页

作者： Yu-jie Wang yan Wang Pei tao School of Ethnic Medicine Chengdu University of Traditional Chinese MedicineChengdu 611137Sichuan ProvinceChina School of Pharmacy Chengdu University of Traditional Chinese MedicineChengdu 611137Sichuan ProvinceChina

Objective:The transformations that occur in diterpenoid alkaloids during the process of sand frying for Chinese herbal medicine preparation have yet to be clarified.This study investigated the structural changes that take place in 3-acetylaconitine during a simulation of heat-processing and evaluated the toxicity and biological activity of the pyrolysis products.Methods:The diterpenoid alkaloid 3-acetylaconitine was heated at 180°C for 15 min to simulate the process of sand frying.The pyrolysis products were separated using column chromatography,and their structures were investigated using high-resolution electrospray ionization mass spectroscopy and nuclear magnetic resonance spectroscopy.Further,in vivo cardiotoxicity and acute toxicity of 3-acetylaconitine and its pyrolysis products were compared,and the aconitine-induced arrhythmia model was employed to evaluate the antiarrhythmic effect of the pyrolysis products.Results:Two new diterpenoid alkaloids,pyroacetylaconitine and 16-epi-pyroacetylaconitine,a pair of epimers at C-16,were isolated.After comparing the structures of these compounds,possible transformation pathways were proposed.Compared with the prototype compound,3-acetylaconitine,the cardiotoxicity and acute toxicity of the heat-transformed products were significantly decreased.In the biological activity assay,the two pyrolysis products exhibited an effective increase in ventricular premature beat latency,a reduction in the occurrence of ventricular tachycardia,as well as an increase in the rate of arrhythmia inhibition,implying strong antiarrhythmic activity.Conclusion:Compared with 3-acetylaconitine,its pyrolysis products displayed lower toxicity and good antiarrhythmic effects;thus,they have potential for being developed into antiarrhythmic medicines.

关键词： 3-Acetylaconitine Acute toxicity Antiarrhythmic agents 16-Epi-pyroacetylaconitine Pyroacetylaconitine Processing

An Accurate Near-Field Distance Estimation Differential Algorithm

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Chinese Journal of Electronics 2022年第5期31卷 851-859页

作者： ZHAO yan tao Haihong CHANG Xin National Key Laboratory of Radar Signal Processing Xidian Univercity The 54th Research Institute China Electronics Technology Group Corporation School of Electronic Engineering Xidian University

The triangular geometry is the basis of near field array accurate distance estimation algorithms.The Fisher expression of traditional distance estimation is derived by utilizing the Taylor series. To improve convergence rate and estimation accuracy, a novel iterative distance estimation algorithm is proposed with differential equations based on the triangular geometry. Firstly, its convergence performance is analysed in detail. Secondly,the selection of the initial value and the number of iterations are respectively studied. Thirdly, compared with the traditional estimation algorithms by utilizing the Fisher approximation, the proposed algorithm has a higher convergence rate and estimation accuracy. Moreover, its pseudocode is presented. Finally, the experiment results and performance analysis are provided to verify the effectiveness of the proposed algorithm.

关键词： Distance estimation Near field Fisher approximation Differential equations Taylor series expansion

Pathways toward wearable and high-performance sensors based on hydrogels:toughening networks and conductive networks

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National Science Review 2023年第9期10卷 286-306页

作者： Junbo Zhu Jingchen tao Wei yan Weixing Song Beijing Key Laboratory for Optical Materials and Photonic Devices Department of Chemistry Capital Normal University

Wearable hydrogel sensors provide a user-friendly option for wearable electronics and align well with the existing manufacturing strategy for connecting and communicating with large numbers of Internet of Things devices.This is attributed to their components and structures,which exhibit exceptional adaptability,scalability,bio-compatibility,and self-healing properties,reminiscent of human skin.This review focuses on the recent research on principal structural elements of wearable hydrogels:toughening networks and conductive networks,highlighting the strategies for enhancing mechanical and electrical properties.Wearable hydrogel sensors are categorized for an extensive exploration of their composition,mechanism,and design approach.This review provides a comprehensive understanding of wearable hydrogels and offers guidance for the design of components and structures in order to develop high-performance wearable hydrogel sensors.

关键词： hydrogels electronic skin toughening networks conductive networks wearable sensors

Comparative investigation on the heat transfer performance of an energy storage system with a spiral tube and straight tube:An experimental approach

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Science China(Technological Sciences) 2023年第1期66卷 71-85页

作者： MAO QianJun CAO yan LI tao School of Urban Construction Wuhan University of Science and TechnologyWuhan 430065China

Latent heat thermal energy storage systems can effectively fill the gap between energy storage and application, and phase-change materials(PCMs) are crucial media for storing thermal energy. Therefore, how to maximize the utilization efficiency of PCMs has attracted widespread attention. In this study, the thermal behavior of two thermal storage units employing a spiral tube and straight tube as heat transfer tubes was experimentally researched and comprehensively compared. Stefan numbers were used to investigate the impact of the heat transfer fluid temperature on the PCM melting process. The temperature distribution of PCMs,temporal evolution of the melting front, and temperature variations of measurement points in both tanks were compared. The average temperature and energy storage of PCMs were calculated to evaluate the thermal performance of different configurations. The results indicate that compared to cylinder B(with a straight tube), the energy storage in cylinder A(with a spiral tube)increased by 78.8%, 38.5%, and 19.6% at Stefan numbers of 1.08, 1.28, and 1.48, respectively. Moreover, the increase in the Stefan number simultaneously ascended the average temperature and energy storage of PCMs in containers A and B, causing the shortening of the melting time. When the Stefan number was increased from 1.28 to 1.48, the storage capacity was raised from3233.18 to 3463.8 k J, and the total melting time was decreased by 34.2% from 547.5 to 360 min after the PCM was loaded in cylinder A. The research results lay a certain foundation for a deeper study of enhanced heat transfer in spiral tubes.

关键词： thermal energy storage visualization experiment PCM spiral tube straight tube