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Development of EPDM composites reinforced by CNTs@SiO_(2)for thermal protection systems of aerospace propulsion:Significant improvement in oxidation and ablation resistance properties

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Chinese Journal of Aeronautics 2024年第2期37卷 471-481页

作者： li WANG jiang li Kang li Yiwei WANG Chenyang MA Science and Technology on Combustion Internal Flow and Thermal-Structure LaboratoryNorthwestern Polytechnical UniversityXi’an 710072China

Carbon Nanotubes(CNTs)reinforced Polymer-Matrix Composites(PMCs)is widely used as insulation materials in thermal protection system of aerospace propulsion.However,CNTs are prone to oxidation and have high thermal conductivities,which makes it difficult to improve the ablation resistance of insulation materials that contain CNTs.SiO_(2)was encapsulated onto the surface of CNTs(CNTs@SiO_(2)),which were then added to Ethylene Propylene Diene Monomer(EPDM)rubber to prepare the insulation materials.Thermogravimetric analysis and ablation test were used to evaluate the resistance of the insulation materials to thermal oxidation and ablation.Additionally,scanning electron microscopy was performed to analyze their microstructures.Results revealed that the addition of CNTs@SiO_(2)could visibly reduce the effects of hot corrosion and ablation on insulation materials.The C-CNTs@SiO_(2)-1 formulation had the best ablative resistance.Further,compared with the unencapsulated formulation(C-CNTs-10),the C-CNTs@SiO_(2)-1 formulation reduced the line ablation rate by 51%to 0.0130 mm/s after oxygen-acetylene experiments.Lastly,the ablation mechanism was investigated based on the effects of the CNTs@SiO_(2)additive on their properties.Thus,the improvement in ablation performance may be attributed to CNTs@SiO_(2)-induced decreases in thermal conductivity,improvement in the hot corrosion resistance in the char layer,and changes in the microstructure.

关键词： Polymer-Matrix Composites(PMCs) Carbon Nanotubes(CNTs) Thermal properties Ablation Oxidation

Effect of Y substitution on the microstructure,magneto-optical,and thermal properties of(Tb_(1−x)Y_(x))_(3)Al_(5)O_(12)transparent ceramics

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Journal of Advanced Ceramics 2024年第4期13卷 529-538页

作者： lixuan Zhang Dianjun Hu Xiao li Ziyu liu Chen Hu Lexiang Wu Tingsong li Dariusz Hreniak jiang li Transparent Ceramics Research Center Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 201899China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou 341000China Institute of Low Temperature and Structure Research Polish Academy of SciencesWroclaw 50-422Poland

Faraday isolators can prevent the front-end system from disturbance and damage caused by a back-reflected beam,so they are important elements in laser systems.As magneto-optical materials are the most important component in Faraday isolators,the studies on magneto-optical materials have attracted much attention these years.Tb_(3)Al_(5)O_(12)(TAG)ceramics are considered to be one of the most promising magneto-optical materials for visible to near-infrared wavelength band application because of their outstanding comprehensive magneto-optical performance.However,the optical quality of TAG ceramics needs further optimization to meet the application requirements.In this work,high optical quality(Tb_(1−x)Y_(x))_(3)Al_(5)O_(12)(x=0,0.05,0.1,0.2,and 0.3)magneto-optical ceramics were fabricated successfully by solid-state reaction sintering combined with hot isostatic pressing(HIP)post-treatment.All the ceramics obtained showed a single garnet phase for different values of x in the range studied.The addition of Y2O3 was found to suppress the secondary phase and improve optical quality significantly.The ceramic samples obtained had clear grain boundaries and possessed the in-line transmittance values of 82.9%at 1064 nm and 82.2%at 633 nm,respectively.The Verdet constants of(Tb_(1−x)Y_(x))_(3)Al_(5)O_(12)ceramics with x=0,0.05,0.1,0.2,and 0.3 were−188.1,−175.4,−168.5,−143.0,and−119.9 rad/(T·m),respectively.The thermal conductivity of TAG ceramics was found to be 5.23 W/(m·K)at 25℃,and when 20%Y was substituted in place of Tb,the thermal conductivity decreased by only 9.4%.

关键词： (Tb_(1−x)Y_(x))_(3)Al_(5)O_(12)ceramics magneto-optical materials optical quality thermal properties

Research on Flexible Job Shop Scheduling Based on Improved Two-Layer Optimization Algorithm

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Computers, Materials & Continua 2024年第1期78卷 811-843页

作者： Qinhui liu Laizheng Zhu Zhijie Gao Jilong Wang jiang li College of Mechanical and Electrical Engineering Harbin Engineering UniversityHarbin150001China

To improve the productivity,the resource utilization and reduce the production cost of flexible job shops,this paper designs an improved two-layer optimization algorithm for the dual-resource scheduling optimization problem of flexible job shop considering workpiece batching.Firstly,a mathematical model is established to minimize the maximum completion time.Secondly,an improved two-layer optimization algorithm is designed:the outer layer algorithm uses an improved PSO(Particle Swarm Optimization)to solve the workpiece batching problem,and the inner layer algorithm uses an improved GA(Genetic Algorithm)to solve the dual-resource scheduling problem.Then,a rescheduling method is designed to solve the task disturbance problem,represented by machine failures,occurring in the workshop production process.Finally,the superiority and effectiveness of the improved two-layer optimization algorithm are verified by two typical cases.The case results show that the improved two-layer optimization algorithm increases the average productivity by 7.44% compared to the ordinary two-layer optimization algorithm.By setting the different numbers of AGVs(Automated Guided Vehicles)and analyzing the impact on the production cycle of the whole order,this paper uses two indicators,the maximum completion time decreasing rate and the average AGV load time,to obtain the optimal number of AGVs,which saves the cost of production while ensuring the production efficiency.This research combines the solved problem with the real production process,which improves the productivity and reduces the production cost of the flexible job shop,and provides new ideas for the subsequent research.

关键词： Dual resource scheduling workpiece batching rescheduling particle swarm optimization genetic algorithm

High photoelectric conversion efficiency and fast relaxation time of FA_(0.4)MA_(0.6)PbI_(3) applied in ultrafast modulation of terahertz waves

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Journal of Energy Chemistry 2024年第4期91卷 299-305页

作者： Zhibo Xu Ying Zeng Xinran Zhao Xiaoyin Chen Aoyu Fan Furi ling jiang li Jianquan Yao School of Optics and Electronic Information Huazhong University of Science and TechnologyWuhan 430074HubeiChina College of Precision Instrument and Optoelectronics Engineering Tianjin UniversityTianjin 300072China Institute of Fluid Physics China Academy of Engineering PhysicsMianyang 621900SichuanChina School of Information Engineering Wuhan University of TechnologyWuhan 430070HubeiChina National Engineering Research Center of Fiber Optic Sensing Technology and Networks Wuhan University of TechnologyWuhan 430070HubeiChina Hubei Key Laboratory of Broadband Wireless Communication and Sensor Networks Wuhan 430070HubeiChina

Active control of terahertz(THz)waves is attracting tremendous attentions in terahertz communications and active photonic devices.Perovskite,due to its excellent photoelectric conversion performance and simple manufacturing process,has emerged as a promising candidate for optoelectronic applications.However,the exploration of perovskites in optically controlled THz modulators is still limited.In this work,the photoelectric properties and carrier dynamics of FA_(0.4)MA_(0.6)PbI_(3)perovskite films were investigated by optical pumped terahertz probe(OPTP)system.The ultrafast carrier dynamics reveal that FA_(0.4)MA_(0.6)PbI_(3)thin film exhibits rapid switching and relaxation time within picosecond level,suggesting that FA_(0.4)MA_(0.6)PbI_(3)is an ideal candidate for active THz devices with ultrafast response.Furthermore,as a proof of concept,a FA_(0.4)MA_(0.6)PbI_(3)-based metadevice with integrating plasma-induced transparency(PIT)effect was fabricated to achieve ultrafast modulation of THz wave.The experimental results demonstrated that the switching time of FA_(0.4)MA_(0.6)PbI_(3)-based THz modulator is near to 3.5 ps,and the threshold of optical pump is as low as 12.7μJ cm^(-2).The simulation results attribute the mechanism of ultrafast THz modulation to photo-induced free carriers in the FA_(0.4)MA_(0.6)PbI_(3)layer,which progressively shorten the capacitive gap of PIT resonator.This study not only illuminates the potential of FA_(0.4)MA_(0.6)PbI_(3)in THz modulation,but also contributes to the field of ultrafast photonic devices.

关键词： Terahertz modulation Perovskites Metamaterials Plasmon-induced transparency

Noteworthy impacts of COVID-19 pandemic on cancer screening:A systematic review

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Fundamental Research 2024年第3期4卷 484-494页

作者： Huilin Wang Min Yang Wei Xiong Quan Wang Bobo Zheng Yang Bai Kaiyong Zou Jibin li Jiansong Ren Wanqing Chen Jingbo Zhai jiang li Office for Cancer Screening National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100021China Department of Comprehensive Intervention National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100021China Department of Gynecology Endocrine&Reproductive Center National Clinical Research Center for Obstetric&Gynecologic Diseases Department of Obstetrics and GynecologyPeking Union Medical College HospitalPeking Union Medical College/Chinese Academy of Medical SciencesBeijing 100005China Ambulatory Surgery Center of Xijing Hospital Fourth Military Medical UniversityXi'an 710068China Department of General Surgery Shaanxi Provincial People’s HospitalXi'an 710068China College of Clinical Medicine Capital Medical UniversityBeijing 100069China School of Public Health Tianjin University of Traditional Chinese MedicineTianjin 301617China

The sudden onset of the coronavirus disease 2019(COVID-19)in January 2020 has affected essential global health services.Cancer-screening services that can reduce cancer mortality are strongly affected.However,the specific role of COVID-19 in cancer screening is not fully understood.This study aimed to assess the efficiency of global cancer screening programs before and during the COVID-19 pandemic and to promote potential cancer-screening strategies for the next pandemic.Electronic searches in PubMed,Embase,and Web of Science,and manual searches were performed between January 1,2020 and March 1,2023.Cohort studies that reported the number of participants who underwent cancer screening before and during the COVID-19 pandemic were included.The methodological quality of the included studies was assessed using the Newcastle-Ottawa Scale.Differences in cancer-screening rates were estimated using the incidence rate ratio(IRR).Fifty-five cohort studies were included in this meta-analysis.The screening rates of colorectal cancer using invasive screening methods(Pooled IRR=0.52,95%CI:0.42 to 0.65,p<0.01),cervical cancer(Pooled IRR=0.56,95%CI:0.47 to 0.67,p<0.01),breast cancer(Pooled IRR=0.57,95%CI:0.49 to 0.66,p<0.01)and prostate cancer(Pooled IRR=0.71,95%CI:0.56 to 0.90,p<0.01)during the COVID-19 pandemic were significantly lower than those before the COVID-19 pandemic.The screening rates of lung cancer(Pooled IRR=0.77,95%CI:0.58 to 1.03,p=0.08)and colorectal cancer using noninvasive screening methods(Pooled IRR=0.74,95%CI:0.50 to 1.09,p=0.13)were reduced with no statistical differences.The subgroup analyses revealed that the reduction in cancer-screening rates varied across economies.Our results suggest that the COVID-19 pandemic has had a noteworthy impact on colorectal,cervical,breast,and prostate cancer screening.Developing innovative cancer-screening technologies is important to promote the efficiency of cancer-screening services in the post-COVID-19 era and prepare for the next pandemic.

关键词： Cancer screening COVID-19 pandemic Cohort study Incidence rate ratio Meta-analysis

Properties and microstructure of copper–titanium alloys with magnesium additions

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Rare Metals 2024年第5期43卷 2290-2299页

作者： Lue Huang li-Jun Peng jiang li Xu-Jun Mi Gang Zhao Guo-Jie Huang Hao-Feng Xie Yi-Cheng Cao Wen-Jing Zhang Zhen Yang State Key Laboratory of Nonferrous Metals and Processes GRINM Group Co. Ltd. GRIMAT Engineering Institute Co. Ltd. School of Materials Science and Engineering Northeastern University General Research Institute for Nonferrous Metals China Academy of Space Technology China Nonferrous Metals Mining Group (Tianjin) Co.Ltd

The volume fractions and morphology of precipitates in precipitation-strengthened Cu-Ti alloys,which precipitate mainly as continuous and discontinuous precipitates,are important for the application of the alloy.This study employed hardness and electrical conductivity tests transmission electron microscopy （TEM）,atom probe tomography （APT）,and first-principles calculations to demonstrate that the addition of Mg is effective for accelerating nanosized continuous β'-Cu4Ti precipitation as well as for suppressing the precipitation of coarse lamellar discontinuous β-Cu4Ti precipitates along the grain boundaries,resulting in Cu-Ti alloys with high yield strength and good electrical conductivity.The results showed that the continuous precipitation of β'-Cu4Ti was accelerated by the Mg additions,which reduced the supersaturation of the matrix,thereby reducing the chemical driving force for the discontinuous precipitates.On the other hand,Mg additions increased the mismatch between the discontinuous β-Cu4Ti precipitates and matrix decreased the nucleation rate of the discontinuous precipitates,and increased the spacing of the discontinuous precipitation layer,resulting in a lower growth rate of the discontinuous precipitates.Therefore,the addition of Mg to Cu-Ti alloys enhances the strength and improves the resistance to over-ageing.

关键词： Cu-Ti-Mg alloy Precipitation hardening Discontinuous precipitation Continuous precipitation Microstructure formation mechanism

Perturbed low-thrust geostationary orbit transfer guidance via polynomial costate estimation

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Chinese Journal of Aeronautics 2024年第3期37卷 181-193页

作者： Zhao li Hengnian li Fanghua jiang Junfeng li State Key Laboratory of Astronautic Dynamics Xi’an Satellite Control CenterXi’an 710043China School of Aerospace Engineering Tsinghua UniversityBeijing 100084China

This paper proposes an optimal,robust,and efficient guidance scheme for the perturbed minimum-time low-thrust transfer toward the geostationary orbit.The Earth’s oblateness perturbation and shadow are taken into account.It is difficult for a Lyapunov-based or trajectory-tracking guidance method to possess multiple characteristics at the same time,including high guidance optimality,robustness,and onboard computational efficiency.In this work,a concise relationship between the minimum-time transfer problem with orbital averaging and its optimal solution is identified,which reveals that the five averaged initial costates that dominate the optimal thrust direction can be approximately determined by only four initial modified equinoctial orbit elements after a coordinate transformation.Based on this relationship,the optimal averaged trajectories constituting the training dataset are randomly generated around a nominal averaged trajectory.Five polynomial regression models are trained on the training dataset and are regarded as the costate estimators.In the transfer,the spacecraft can obtain the real-time approximate optimal thrust direction by combining the costate estimations provided by the estimators with the current state at any time.Moreover,all these computations onboard are analytical.The simulation results show that the proposed guidance scheme possesses extremely high guidance optimality,robustness,and onboard computational efficiency.

关键词： Low thrust Orbital transfer Trajectory optimization Guidance Indirect method Orbital averaging Machine learning Geostationary satellites

Heat Transfer and Friction Characteristics of Printed Circuit Heat Exchangers with Different Channel Structures for S-CO_(2) Power System

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Journal of Thermal Science 2024年第3期33卷 1132-1147页

作者： jiang Tao li Mingjia Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of Education School of Energy and Power EngineeringXi’an Jiaotong UniversityXi’an710049China School of Mechanical Engineering Beijing Institute of TechnologyBeijing100081China

Printed circuit heat exchanger(PCHE)has been widely used in supercritical carbon dioxide(S-CO_(2))power systems because of its high heat transfer efficiency and good compactness.However,due to the large variety of PCHE configurations,channel selection in practical applications lacks a basis.Therefore,this paper discussed the heat transfer and friction characteristics and the synergy of three fields in the channel under the guidance of the field synergy principle for four typical PCHE channels.Additionally,the comprehensive performance of four channels was compared.Finally,the heat transfer and friction factor correlations for S-CO_(2)in four channels were established.The findings demonstrate that the synergy of velocity and pressure fields of the straight channel PCHE is better(β≈180°),so its resistance loss is relatively small.The zigzag and sinusoidal wavy channels and the airfoil fins can reduce the angle a between the temperature gradient and velocity,thus enhancing the heat transfer.The sinusoidal wavy channel can reduce flow resistance compared to the zigzag channel due to the rounded corners.The streamlined airfoil structure can guide the flow and reduce backflow,thus reducing resistance losses.In the range of Re studied in this paper,the maximum error of the proposed heat transfer and friction factor correlations of PCHE is 7.0%,which shows good fitting accuracy.The research in this paper can provide a reference for the selection and design of PCHE with different channel configurations.

关键词： printed circuit heat exchanger supercritical carbon dioxide typical channel structure field synergy analysis

OSMR is a potential driver of inflammation in amyotrophic lateral sclerosis

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Neural Regeneration Research 2024年第11期19卷 2513-2521页

作者： Wenzhi Chen Shishi jiang Shu li Cheng li Renshi Xu Department of Neurology Jiangxi Provincial People’s HospitalXiangya Hospital Jiangxi Hospital of Central South UniversityThe Clinical College of Nanchang Medical CollegeThe First Affiliated Hospital of Nanchang Medical CollegeNanchangJiangxi ProvinceChina

Amyotrophic lateral sclerosis is a neurodegenerative disease,and the molecular mechanism underlying its pathology remains poorly understood.However,inflammation is known to play an important role in the development of this condition.To identify driver genes that affect the inflammatory response in amyotrophic lateral sclerosis,as well as potential treatment targets,it is crucial to analyze brain tissue samples from patients with both sporadic amyotrophic lateral sclerosis and C9orf72-related amyotrophic lateral sclerosis.Therefore,in this study we used a network-driven gene analysis tool,NetBID2.0,which is based on SJARACNe,a scalable algorithm for the reconstruction of accurate cellular networks,to experimentally analyze sequencing data from patients with sporadic amyotrophic lateral sclerosis.The results showed that the OSMR gene is pathogenic in amyotrophic lateral sclerosis and participates in the progression of amyotrophic lateral sclerosis by mediating the neuroinflammatory response.Furthermore,there were differences in OSMR activity and expression between patients with sporadic amyotrophic lateral sclerosis and those with C9orf72-related amyotrophic lateral sclerosis.These findings suggest that OSMR may be a diagnostic and prognostic marker for amyotrophic lateral sclerosis.

关键词： amyotrophic lateral sclerosis driver neuroinflammation OSMR C9ORF72 neurodegenerative disease pathogenesis oxidative stress protein misfolding mitochondrial dysfunction