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Development of the NWPU20 Micro Air Vehicle

西北工业大学学报 2005年第4期23卷 417-421页

作者： Li Zhanke Song Bifeng zhang yafeng zhang Wei zhang Yizhe College of Aeronautics Northwestern Polytechnical University Xi＇an 710072 China

This paper reports the design, construction, and operation of NWPU20 Micro Air Vehicle (MAV), which is the smallest that has, up to now, been developed in PR China. The miniaturization level in PR China makes smaller MAV, in our opinion, not possible to implement. The NWPU20 is a 20-centimeter span, battery powered, fixed-wing aircraft with an off-the-shelf color video camera that can transmit live video back to the ground station. The on-board electronic subsystems are smallest and lightest among the commercial products, including an 8-gram wireless video camera, an 8-gram receiver, a 5-gram electronic speed controller (ESC), two 4.5-gram fully proportional radio frequency control servos, and the total mass of NWPU20 is less than 80 grams. An experimental model was fabricated and tested in the Low Turbulent Flow Wind Tunnel (LTFWT) at Northwestern Polytechnical University (NWPU) to research low Reynolds number flow characteristics of the NWPU20. The result of the wind tunnel test shows that stall angle of attack of NWPU20 can reach 30°, which is higher than that of the general aircrafts, and the maximum lift-to-drag ratio of NWPU20 can nearly reach 6 at the angle of attack of 10°, which can satisfy design requirements of the NWPU20. A small-sized propulsion/torque testing system was developed to measure and analyze the propulsion and torque performances of the motor-propeller combination used in the NWPU20. A center of gravity (c.g.) testing apparatus was developed and used to adjust the c.g. of the NWPU20 so that it has good longitudinal static stability and control. The NWPU20 prototype has undergone successfully flight tests many times; it flies at 32 kilometers per hour, with an endurance of 15 minutes, and a maximum communications range of 300 meters. With the color video camera, NWPU20 successfully transmits real-time video back to the ground station. The success of NWPU20 proves preliminarily that 20-centimeter span micro air vehicle is feasible and usable.

关键词：微型飞行器空气动力学风力流动 Reynolds数字

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Tribological Behaviors of Electroless Nickel-Boron Coating on Titanium Alloy Surface

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Chinese Journal of Mechanical Engineering 2024年第1期37卷 309-320页

作者： Yao Jia Jianping Lai Jiaxin Yu Huimin Qi yafeng zhang Hongtu He Key Laboratory of Testing Technology for Manufacturing Process in Ministry of Education State Key Laboratory of Environment-Friendly Energy MaterialsSouthwest University of Science and TechnologyMianyang 621010China

Titanium alloys are excellent structural materials in engineering fields,but their poor tribological properties limit their further *** plating is an effective method to enhance the tribological performance of alloys,but it is difficult to efficiently apply to titanium alloys,due to titanium alloy’s strong chemical *** this work,the electroless Nickel-Boron(Ni-B)coating was successfully deposited on the surface of titanium alloy(Ti-6AL-4V)via a new pre-treatment ***,linearly reciprocating sliding wear tests were performed to evaluate the tribological behaviors of titanium alloy and its electroless Ni-B *** was found that the Ni-B coatings can decrease the wear rate of the titanium alloy from 19.89×10^(−3)mm^(3)to 0.41×10^(−3)mm^(3),which attributes to the much higher hardness of Ni-B *** heat treatment,the hardness of Ni-B coating further increases corresponding to coating crystallization and hard phase ***,heat treatment does not improve the tribological performance of Ni-B coating,due to the fact that higher brittleness and more severe oxidative wear exacerbate the damage of heat-treated ***,the Ni-B coatings heat-treated both in air and nitrogen almost present the same tribological *** finding of this work on electroless coating would further extend the practical applications of titanium alloys in the engineering fields.

关键词： Electroless coating Titanium alloy Tribology Wear Heat treatment Nanoindentation

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Quantitative analysis of the tribological properties of phosphate glass at the nano- and macro-scales

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Friction 2021年第5期9卷 1138-1149页

作者： Huimin QI Wen HU Hongtu HE yafeng zhang Chenfei SONG Jiaxin YU Key Laboratory of Testing Technology for Manufacturing Process in Ministry of Education State Key Laboratory of Environment-friendly Energy MaterialsSouthwest University of Science and TechnologyMianyang 621010China National United Engineering Laboratory for Advanced Bearing Tribology Henan University of Science and TechnologyLuoyang 471023China

Processing(grinding,polishing)of phosphate laser(PL)glass involves material removal at two vastly different(spatial)*** this study,the nano‐and macro‐tribological properties of PL glass are investigated by rubbing the glass against a SiO_(2) counter‐surface in both dry and humid *** results indicate that the friction of the PL glass/SiO_(2) pair has opposing trends at the nano‐and *** the nanoscale,the friction coefficient(COF)in humid air is much higher than in dry air,which is attributed to the capillary effect of the absorbed water‐film at the *** the macroscale,on the other hand,the COF in humid air is lower than in dry air,because the water‐related mechanochemical wear makes the worn surface less susceptible to *** removal for PL glass is better facilitated by humid air than by dry air at both scales,because the stress‐enhanced hydrolysis accelerates the material‐removal process in ***,the material‐removal is more sensitive to contact pressure at the macroscale,because stronger mechanical‐interaction occurs during material removal at the macroscale with the multi asperity contact *** the macroscale,the material removal is more sensitive to contact pressure in humid air compared to dry *** almost all mechanical energy is used to remove material in humid air,and most of the mechanical energy is used to produce cracks in PL glass in dry *** results of this study can help optimize the multi‐scale surface processing of optical glasses.

关键词： phosphate glass friction wear water hydrolysis tribochemistry

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Fabrication,microstructures,and properties of copper matrix composites reinforced by molybdenum-coated carbon nanotubes

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Rare Metals 2011年第4期30卷 401-407页

作者： NIE Junhui JIA Chengchang JIA Xian zhang yafeng SHI Na LI Yi School of Matertals Sctence and Engmeermg Umverszty of Sctence and Technology Beijing Beijing 100083 China China Iron ＆ Steel Research Institute Group Beijing 100081 China

Multiwalled carbon nanotubes （CNTs） were coated by a molybdenum layer using carbonyl thermal decomposition process with a precursor of molybdenum hexacarbonyl. The Mo-coated CNTs （Mo-CNTs） were added into copper powders to fabricate Mo-CNT/Cu composites by means of mechanical milling followed by spark plasma sintering. The Mo-CNTs were uniform dispersion in the Cu matrix when their contents were 2.5 vo1.%-7.5 vol.%, while some Mo-CNT clusters were clearly observed at additions of 10.0 vo1.%-15.0 vol.% Mo-CNTs in the mixture. The mechanical, electrical, and thermal properties of the Mo-CNT/Cu composites were characterized, and the results showed that the tensile strength and hardness were 2.0 and 2.2 times higher than those of CNT-free specimens, respectively. Moreover, the Mo-CNT/Cu composites exhibited an enhanced thermal conductivity but inferior electrical conductivity compared with sintered pure Cu. The uncoated CNT/Cu composites were fabricated by the similar processes, and the measured tensile strength, hardness, thermal conductivity, and electrical conductivity of the CNT/Cu composites were lower than those of the Mo-CNT/Cu composites.

关键词： metallic matrix composites mechanical properties ball milling molybdenum carbon nanotubes

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喹啉酮衍生物的生物活性与荧光性能研究进展

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化学与生物工程 2025年第2期42卷 9-15,23页

作者：王静张亚峰王艳慧金丹刘思彤孙东明中钢集团鞍山热能研究院有限公司煤焦油系新型材料制备技术国家地方联合研究工程中心辽宁鞍山114044

喹啉酮衍生物是天然产物结构基序和多种药物结构骨架的重要组成部分,具有高荧光量子产率和高稳定性的荧光性能。综述了喹啉酮衍生物的生物活性与荧光性能研究进展,为喹啉酮衍生物在药理学活性与荧光探针方面的研究提供了借鉴和参考。

关键词：喹啉酮生物活性荧光性能

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Peptide-RNA complexation-induced fluorescence“turn on”displacement assay for the recognition of small ligands targeting HIV-1 RNA

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Journal of Pharmaceutical Analysis 2022年第6期12卷 923-928页

作者： Liang Qi Jiayun zhang Ying Gao Pin Gong Chengyuan Liang Yao Su Qiao Zeng yafeng zhang Department of Pharmacy School of Food and Biological EngineeringShaanxi University of Science&TechnologyXi'an710021China Xi'an Institute for Food and Drug Control Xi'an710054China

The regulator of expression of virion(Rev)protein binds specifically to the Rev-responsive element(RRE)RNA in order to regulate the expression of the human immunodeficiency virus(HIV)-1 *** indicator displacement assays have been used to identify ligands that can inhibit the ReveRRE interaction;however,the small fluorescence indicators cannot fully replace the Rev peptide or *** a result,a single rhodamine B labeled Rev(RB-Rev)model peptide was utilized in this study to develop a direct and efficient ReveRRE inhibitor screening *** to photon-induced electron transfer quenching of the tryptophan residue on the RB fluorophore,the fluorescence of RB in Rev was weakened and could be dramatically reactivated by interaction with RRE RNA in ammonium acetate buffer(approximately six times).The interaction could reduce the electron transfer between tryptophan and RB,and RRE could also increase RB *** inhibitor screening model was evaluated using three known positive ReveRRE inhibitors,namely,proflavin,6-chloro-9-[3-(2-chloroethylamino)propylamino]-2-methoxyacridine(ICR 191),and neomycin,as well as a negative drug,*** the addition of the positive drugs,the fluorescence of the ReveRRE decreased,indicating the displacement of *** was confirmed using atomic force microscopy(AFM)and the fluorescence was essentially unaffected by the addition of *** results demonstrated that RB-Rev can be used as a fluorescent probe for recognizing small ligands that target RRE *** ReveRRE inhibitor screening model offers a novel approach to evaluating and identifying long-acting Rev inhibitors.

关键词： RRE RNA Rev protein Fluorescence enhancement Ligand-RNA interaction Drug screening

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Processing of a Novel Zn Alloy Micro-Tube for Biodegradable Vascular Stent Application

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Journal of Materials Science & Technology 2016年第9期32卷 925-929页

作者： Chang Wang Zhentao Yu Yajun Cui yafeng zhang Sen Yu Gongqi Qu Haibo Gong Northwest Institute for Nonferrous Metal Research Xi'an 710016China Xi'an University of Architecture and Technology Xi'an 710055China Xi'an Advanced Medical Technology Co. LtdXi'an 710077China

In recent years, zinc based alloys as a new biodegradable metal material aroused intensive interests. However, the processing of Zn alloys micro-tubes （named slender-diameter and thin-walled tubes） is very difficult due to their HCP crystal structure and unfavorable mechanical properties. This study aimed to develop a novel technique to produce micro-tube of Zn alloy with good performance for biodegrad- able vascular stent application. In the present work, a processing method that combined drilling, cold rolling and optimized drawing was proposed to produce the novel Zn-5Mg-1Fe （wt%） alloy micro- tubes. The micro-tube with outer diameter of 2.5 mm and thickness of 130 μm was fabricated by this method and its dimension errors are within 10 μm. The micro-tube exhibits a fine and homogeneous microstructure, and the ultimate tensile strength and ductility are more than 220 MPa and 20% respectively. In addition, the micro-tube and stents of Zn alloy exhibit superior in vitro corrosion and expansion performance. It could be concluded that the novel Zn alloy micro-tube fabricated by above method might be a promising candidate material for biodegradable stent.

关键词： Zn alloy Micro-tube Biodegradable stent Mechanical properties Dimensional accuracy In vitro corrosion performance

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Therapeutic efficacy of traditional Chinese exercises and massage treatment on lumbar instability:a randomized controlled trial

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Journal of Traditional Chinese Medicine 2020年第6期40卷 1026-1032页

作者： Chen Wenjin Wang Jianwei Zhou Zhiyi Ren Yide Hua Zhen Yan Zheng zhang yafeng Department of Orthopedics Wuxi Affiliated Hospital of Nanjing University of Chinese MedicineJiangsu 214071China Wuxi Huishan Traditional Chinese Medicine hospital Jiangsu 214071China College of Information Science and Engineering Huaqiao University Fujian 361021China

OBJECTIVE:To determine the effect of traditional Chinese exercises combined with traditional Chinese massage on lumbar ***:Seventy patients with lumbar instability were randomly divided into experimental group and control *** experimental group was treated with traditional Chinese exercises combined with traditional Chinese massage,while the control group was only treated with traditional Chinese *** Japanese Orthopaedic Association(JOA)scores,Oswestry Disability Index(ODI)and dynamic imaging indexes were used to assess treatment ***:After 8 weeks of treatment,the JOA scores of both groups were significantly higher than those before treatment(P<0.05),while ODI was significantly lower(P<0.05).In addition,compared with the control group,the JOA score of the experimental group was significantly increased(P<0.05),and the ODI was significantly decreased(P<0.05).Besides,the dynamic imaging indexes of patients with lumbar instability significantly changed after *** lumbar vertebral laxity was significantly decreased(P<0.05)than those before ***:The traditional Chinese exercises and massage may improve the symptoms of lumbar instability,and traditional Chinese exercises combined with massage treatment may be better than exercises alone.

关键词： Joint instability Exercise therapy Massage Medicine Chinese traditional Randomized controlled trial

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CIFTIS,a Shot in Arm to Global Economic Recovery

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China Today 2020年第10期69卷 6-11页

作者： zhang yafeng 不详

The staging of the 2020 China International Fair for Trade in Services(CIFTIS),which lasted from September 4-9 in Beijing,reflects China’s rock-solid determination to further open up its market,strengthen cooperation,and give a shot in the arm to global economic ***“Global Services,Shared Prosperity,”the first major international economic and trade event since the COVID-19 outbreak was held both online and *** encompassed the Global Trade in Services Summit,four summit forums,and more than 100 other industry seminars and forums.

关键词： Services Trade Global

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Effects of shrubs and precipitation on spatial-temporal variability of soil temperature in microhabitats induced by desert shrubs

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Research in Cold and Arid Regions 2013年第2期5卷 197-204页

作者： yafeng zhang XinPing Wang Rui Hu YanXia Pan Shapotou Desert Research and Experiment Station Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences University of Chinese Academy of Sciences

Soil temperatures at 0, 5, 10 and 20 cm depths were monitored cominuously at different microhabitats （beneath shrub canopy （BSC）; bare intershrub spaces （BIS）） induced by xerophytic shrub （Caragana korshinskii Kom.） canopy, respectively. We mainly aimed to assess the effects of shrub canopy and precipitation on the spatial-temporal variability of soil temperature. Results indi- cate that both precipitation and vegetation canopy significantly affect soil temperature. In clear days, soil temperatures within the BSC area were significantly lower than in the BIS at the same soil depth due to shading effects of shrub canopy. Diurnal variations of soil temperature show a unimoclal sinusoidal curve. The amplitude of soil temperature tended to decrease and a hysteresis of di- urnal maximum soil temperature existed at deeper soil layers. Vertical fluctuations of soil temperature displayed four typical curves. In the nighttime （approximately from sunset to sunrise）, surface temperature within the BSC area was higher than in the BIS. In rainy days, however, soil temperatures were affected mainly by precipitation and the shrub canopy had a negligible effect on soil temperature, and little difference in soil temperature at the same soil depth was found between the BSC area and in the BIS. Diurnal variations in soil temperature decreased exclusively as rainfall continued and the vertical fluctuations of soil tempera~＇e show an increased tendency with increasing soil depth.

关键词： desert shrub precipitation soil temperature shading beneath shrub canopy bare intershrub spaces

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