Development and on-orbit operation of loop heat pipes on chinese circumlunar return and reentry spacecraft

Zhang Hongxing,Mi Min,Miao Jianyin,Wang Lu,Chen Yang,Ding Ting,Ning Xianwen,Huo Yuhua 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.6

This paper describes the development and result of ground experiment and analyzes the on-orbit operation of Loop heat pipes (LHP) for the Chinese circumlunar return and reentry spacecraft. A novel LHP was developed to satisfy the thermal control requirements of Inertial measurement units (IMU). The LHP consisted of an integrated evaporator subassembly, a cambered condenser, and an electric explosion valve. Ground experiments were conducted to investigate the startup characteristics, and heat transfer and heat insulation performance of the LHPs. During a flight mission, the LHPs work as a thermal switch and perform both heat transfer and insulation functions. Before returning to the earth’s atmosphere, the valves of the reentry capsule are opened to discharge working fluid and prevent heat transfer from the capsule wall to the devices. In the flight mission, the LHPs performed all the required functions, and the IMU temperatures were maintained within an allowable range.

Mechanical and surface properties of HF50S carbon fibers

Gu Hongxing,Zhang Ming,Zhang Shubin,Qi Jingyao 한국탄소학회 2022 Carbon Letters Vol.32 No.3

To thoroughly analyze the mechanical properties and surface conditions of HF50S carbon fibers, the tensile properties, surface morphology, surface chemical element, surface energy, sizing agent properties, and Naval Ordnance Laboratory (NOL) ring of their composites were characterized. Furthermore, the aforementioned properties were exhaustively compared with those of T1000G carbon fibers. The results showed that the tensile strength, modulus, and elongation of the HF50S carbon fibers were 6638 MPa, 297 GPa, and 2.2%, respectively, thus demonstrating that the mechanical properties of the HF50S carbon fibers were on par with those of the T1000G carbon fibers, in addition, the coefficient of variation (Cv) indices of HF50S carbon fiber were below 3%, indicating good stability. The HF50S carbon fibers have a smooth surface without grooves, which is analogous to that of the T1000G carbon fibers prepared by the typical dry jet–wet spinning process. The main component of the sizing agent of the HF50S carbon fibers is an epoxy resin, which is also used for the preparation of epoxy matrix composites. Because the HF50S carbon fiber surface has greater O and N contents than the T1000G carbon fiber surface, the HF50S carbon fibers have more active functional groups and higher surface activity. The surface energy of the HF50S carbon fibers is 30.13 mJ/m2, which is higher than that of the T1000G carbon fibers (28.42 mJ/m2). Owing to the higher strength and surface activity of the HF50S carbon fibers than those of the T1000G carbon fibers, the strength and strength conversion of NOL ring based on the former are slightly higher than those of that prepared using the latter.

A New Method to Separate Horizontal Solar Radiation into Direct and Diffuse Components

ZHANG Qingyuan,LOU Chengzhi,YANG Hongxing 한국태양에너지학회 2004 한국태양에너지학회 학술대회논문집 Vol.- No.-

Human capital, financial constraints, and innovation investment persistence

Peng Hongxing,Tan Hongping,Zhang Yin 기술경영경제학회 2020 ASIAN JOURNAL OF TECHNOLOGY INNOVATION Vol.28 No.3

We examine the impact of human capital on innovation investment persistence using a sample of high-tech companies listed in the Chinese A-share market for the period 2009–2017. We find that human capital mitigates the negative effect of financial constraints on innovation investment persistence. We further explore the mechanism through which human capital at the management and employee levels affects innovation investment persistence. We find that management human capital affects innovation investment persistence through the expectation of authorised patents, while employee human capital affects the persistence through salary stickiness. Furthermore, we find that management human capital contributes to an increase in future granted patents through persistent innovation investment.

Effect of Sodium Nitroprusside on Postharvest Quality and Senescence of Wax Apple

Ruining Zhang,Zhouyu Yuan,Ping Chen,Hongxing Cao,Jerome Jeyakumar John Martin 한국원예학회 2021 원예과학기술지 Vol.39 No.6

Wax apple is one of the most important commercially grown fruits and is consumed worldwide due to its excellent quality attributes and high degree of acceptance by consumers. However, wax apple is highly perishable and the application of storage and other postharvest technologies is necessary to maintain fruit quality from harvest to consumption. In this study, the effects of sodium nitroprusside (SNP) on the postharvest quality and senescence of wax apple (Syzygium samarangense (Blume) Merr. & Perry) was investigated. The wax apples were treated with three concentrations of SNP (1, 2.5, and 5 μmol·L<SUP>-1</SUP>), and the control was treated with distilled water. The treated fruits were air dried naturally and stored at 25°C (the relative humidity was 90%) for 7 days to determine the various parameters. The results demonstrated that soaking in SNP maintained higher titratable acidity (TA) and soluble solids content (SSC) and sustained a stable Brix-acid ratio (BAR). SNP also suppressed the degradation of anthocyanins and the decrease of firmness. Additionally, it functioned in delayed polyphenol oxidase (PPO) and peroxidase (POD) activities in the early period and suppressed the decrease of the two enzyme activities in the late period. Increases in malondialdehyde (MDA) content were inhibited. In summary, 2.5 μmol·L<SUP>-1</SUP> SNP significantly maintained the quality and suppressed the senescence of postharvest wax apple fruit compared to the control. Therefore, the application of SNP may represent a promising and practical methodology for extending the shelf life of fruit.

Optimized Thermoelectric Properties of AgSbTe2 through Adjustment of Fabrication Parameters

Jian Zhang,Xiaoying Qin,Di Li,송천준,Yongfei Liu,Hongxing Xin,Tianhua Zou,Yuanyue Li 대한금속·재료학회 2015 ELECTRONIC MATERIALS LETTERS Vol.11 No.1

AgSbTe2 bulk sample is obtained by hot-pressing under different fabricationparameters, and their thermoelectric properties are investigated in thetemperature range of 300 - 550 K. The highest ZT = 0.86 is achieved at475 K for the sample hot-pressed at 423 K and 500MPa due to the lowerthermal conductivity and higher power factor. The results indicate that theoptimized thermoelectric properties can be obtained for AgSbTe2 compoundat the sintering temperature of 423 K under the pressure of 500 MPa.

Design and Characteristic Measurement of 8000 mm Large Aperture Integrating Sphere

Zhao Zhang,Zhi Wan,Xiansheng Li,Hongxing Liu,Jingxu Sun,Zexun Liu,Yamin Wang,Jianwei Ren,Jianyue Ren 한국광학회 2016 Current Optics and Photonics Vol.20 No.4

Integrating spheres play a central role in the radiometric calibration of remote sensors. With thedevelopment of the wide field of view (FOV) remote sensors, aperture diameters of remote sensors arebecoming larger and larger. To satisfy the radiometric calibration requirements of full FOV and fullaperture, an 8000mm diameter large aperture integrating sphere uniform source with a variable exit portwas designed and manufactured. This integrating sphere will be used for pre-launch test and radiometriccalibration of remote satellites. In this paper, optical theories were used to design the output spectralradiance. The LightTools software based on ray-tracing simulation method was used to determine the bestcombination and distribution of inner light sources. A spectral experiment was made to verify the spectralradiance design. To reduce the influence of longtime power-on, a new characteristic measurement methodwas developed to obtain the radiation characteristic of the integrating sphere, which could greatly improvethe measuring efficiency. This method could also be applied to measure other large aperture uniformsources. The obtained results indicate that the spatial uniformity is 98.35%, and the angular uniformityat center position is 98.78%.

Engineering a High-Affinity PD-1 Peptide for Optimized Immune Cell-Mediated Tumor Therapy

Yilei Chen,Hongxing Huang,Yin Liu,Zhanghao Wang,Lili Wang,Quanxiao Wang,Yan Zhang,Hua Wang 대한암학회 2022 Cancer Research and Treatment Vol.54 No.2

Purpose The purpose of this study was to optimize a peptide (nABP284) that binds to programmed cell death protein 1 (PD-1) by a computer-based protocol in order to increase its affinity. Then, this study aimed to determine the inhibitory effects of this peptide on cancer immune escape by coculturing improving cytokine-induced killer (ICIK) cells with cancer cells. Materials and Methods nABP284 that binds to PD-1 was identified by phage display technology in our previous study. AutoDock and PyMOL were used to optimize the sequence of nABP284 to design a new peptide (nABPD1). Immunofluorescence was used to demonstrate that the peptides bound to PD-1. Surface plasmon resonance was used to measure the binding affinity of the peptides. The blocking effect of the peptides on PD-1 was evaluated by a neutralization experiment with human recombinant programmed death-ligand 1 (PD-L1) protein. The inhibition of activated lymphocytes by cancer cells was simulated by coculturing of human acute T lymphocytic leukemia cells (Jurkat T cells) with human tongue squamous cell carcinoma cells (Cal27 cells). The anticancer activities were determined by coculturing ICIK cells with Cal27 cells in vitro. Results A high-affinity peptide (nABPD1, KD=11.9 nM) for PD-1 was obtained by optimizing the nABP284 peptide (KD=11.8 μM). nABPD1 showed better efficacy than nABP284 in terms of increasing the secretion of interkeulin-2 by Jurkat T cells and enhancing the in vitro antitumor activity of ICIK cells. Conclusion nABPD1 possesses higher affinity for PD-1 than nABP284, which significantly enhances its ability to block the PD-1/PD-L1 interaction and to increase ICIK cell-mediated antitumor activity by armoring ICIK cells. PurposeThe purpose of this study was to optimize a peptide (nABP284) that binds to programmed cell death protein 1 (PD-1) by a computer-based protocol in order to increase its affinity. Then, this study aimed to determine the inhibitory effects of this peptide on cancer immune escape by coculturing improving cytokine-induced killer (ICIK) cells with cancer cells.Materials and MethodsnABP284 that binds to PD-1 was identified by phage display technology in our previous study. AutoDock and PyMOL were used to optimize the sequence of nABP284 to design a new peptide (nABPD1). Immunofluorescence was used to demonstrate that the peptides bound to PD-1. Surface plasmon resonance was used to measure the binding affinity of the peptides. The blocking effect of the peptides on PD-1 was evaluated by a neutralization experiment with human recombinant programmed death-ligand 1 (PD-L1) protein. The inhibition of activated lymphocytes by cancer cells was simulated by coculturing of human acute T lymphocytic leukemia cells (Jurkat T cells) with human tongue squamous cell carcinoma cells (Cal27 cells). The anticancer activities were determined by coculturing ICIK cells with Cal27 cells <i>in vitro</i>.ResultsA high-affinity peptide (nABPD1, K_D=11.9 nM) for PD-1 was obtained by optimizing the nABP284 peptide (K_D=11.8 μM). nABPD1 showed better efficacy than nABP284 in terms of increasing the secretion of interkeulin-2 by Jurkat T cells and enhancing the <i>in vitro</i> antitumor activity of ICIK cells.ConclusionnABPD1 possesses higher affinity for PD-1 than nABP284, which significantly enhances its ability to block the PD-1/PD-L1 interaction and to increase ICIK cell-mediated antitumor activity by armoring ICIK cells.

Trust Based Service Selection in Cloud Computing Environment

Xiaohui Li,Hongxing Liang,Xing Zhang 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.11

In order to meet cloud user demand for managed service, we propose a scheme based on trust for cloud service selection. The scheme includes the service chosen and services delivered two parts, which can choose the cloud service through its trust value, to meet the safety requirements premise, and make trust decisions to achieve service controllability. First it make choice of the service in accordance with service attributes weight using AHP, then complete user data delivery rely on trust, which allowing users to combine with their own situation and trust in cloud services dynamically adjusting the cloud user data release granularity to reach the controllability of the service .Instance results show that the scheme is effective and can guarantee service selection under safe and controlled conditions.

Improved Genetic Algorithm based 3-D deployment of UAVs

Xiting Wen,Yuhan Ruan,Yongzhao Li,Hongxing Xia,Rui Zhang,Chao Wang,Wei Liu,Xiaoyu Jiang 한국통신학회 2022 Journal of communications and networks Vol.24 No.2

Unmanned aerial vehicles (UAVs) are widely usedas aerial base stations (BSs) to provide flexible connectivity andcoverage for ground users in various scenarios such as disasterrelief, traffic offloading, and so on. Especially, UAV deployment isan important issue that directly affects the coverage performanceof the UAV network. In this paper, we propose a novel heuristic algorithmbased three-dimensional (3-D) UAV deployment schemewhile guaranteeing the connectivity of the UAV network in bothstatic and dynamic user scenarios. For the static user scenario, weaim to deploy the minimum number of UAVs to provide coveragefor the users from the perspective of deployment cost. To reducethe deployment complexity, we decouple the 3-D UAV deploymentproblem from the vertical and horizontal dimensions. Specifically,we firstly determine the optimal vertical height of UAVs based onthe air-to-ground (A2G) model. Then, to alleviate the prematureconvergence of standard genetic algorithm (SGA), we designan improved genetic algorithm (IGA) to obtain the optimalhorizontal locations of UAVs. On this basis, when the users moveor increase, i.e., the dynamic user scenario, the already deployedUAVs cannot provide effective coverage. For this scenario, wepropose a UAV redeployment scheme to maximize the numberof covered users without increasing the number of UAVs. Tofurther reduce the cost of redeployment, we firstly modify theproposed IGA to obtain a feasible set of two-dimensional (2-D)redeployed locations of the UAVs. Then, we design a backtrackingalgorithm (BA) based UAV movement strategy to minimize thetotal flying distance of the UAVs. The simulation results showthat the effectiveness and convergence of our proposed schemes.