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A Novel Synchronization Method in Terahertz Large-Scale Antenna Array System

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Chinese Journal of Electronics 2021年第5期30卷 956-968页

作者： ZHENG Chen DING Xuhui LIU Dekang bu Xiangyuan AN Sining School of Information and Electronics Beijing Institute of Technology Microwave Electronics Laboratory Department of Microtechnology and Nanoscience Chalmers University of Technology

We focus on the problems of the accurate time delay estimation, the design of training pilots,and hybrid matrix optimization within the large-scale antenna array Terahertz(THz) broadband communication system. In contrast to the existing researches based on narrow-band arrays, we hereby shed light on the time delay estimation of broadband arrays. In THz broadband communication systems, the data symbol duration is relatively short when comparing with the dimension of the antenna array. In large-scale antenna systems,signals received in each antenna are no longer different phase-shifted copies of the same symbol, but completely different symbols in which occasion traditional narrowband structure is no longer suitable. Based on the above conclusion, firstly, we put forward a system model based on large-scale antenna arrays and Time delay line(TDL)structure. Secondly, we deduce the Cramer-Rao lower bound(CRLB) of the time delay estimation, and present a time delay estimation algorithm that could reach the CRLB. Thirdly, by minimizing the CRLB, we address the design of the training pilot and optimized TDL structure under the condition of constant envelope training pilot and modulus TDL structure. Finally, we disclose the numerical simulation results. According to the simulation results, the aforementioned method is workable in reaching the CRLB,the TDL structure can significantly surpass that of the traditional model, and the optimal pilot design method outperforms the pseudo-random pilot structure.

关键词： OFDM modulation time-domain analysis time delay estimation algorithm narrow-band arrays constant envelope training pilot frequency estimation synchronisation hybrid matrix optimization different phase-shifted copies completely different symbols THz broadband communication systems large-scale antenna systems optimal pilot design method Terahertz large-scale antenna array system modulus TDL structure occasion traditional narrow-band structure channel estimation large-scale antenna array Terahertz broadband communication system optimized TDL structure data symbol duration CRLB large-scale antenna arrays array signal processing pseudorandom pilot structure broadband arrays system model accurate time delay estimation antenna arrays Time delay line structure delay estimation

Combined algorithm of acquisition and anti-jamming based on SFT

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Journal of Systems Engineering and Electronics 2015年第3期26卷 431-440页

作者： Ying Ma Xiangyuan bu Hangcheng Han Qiaoxian Gong School of Information and Electronics Beijing Institute of Technology

A communication and navigation receiver is required to remove hostile jamming signals and synchronize receiving signals effectively especially for satellite communication and navigation whose resources are becoming more and more limited. This paper proposes a novel signal receiving method by combining the pro- cesses of anti-jamming and synchronization to reduce the overall computationa~ complexity at the expense of slightly affecting the detection probability, which is analyzed in detail by derivations. Furthermore, this paper introduces sparse Fourier transformation （SFT） into the proposed algorithm to replace fast Fourier transfor- mation （FFT） so as to further reduce the calculation time especially in large frequency offset environments.

关键词： acquisition anti-jamming navigation sparse Fourier transformation (SFT).

Room-temperature plasticity in diamond

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Science China(Technological Sciences) 2021年第1期64卷 32-36页

作者： bu YeQiang WANG Peng NIE AnMin WANG HongTao Center for X-mechanics Zhejiang UniversityHangzhou 310027China Institute of Applied Mechanics Zhejiang UniversityHangzhou 310027China Materials Genome Institute Shanghai UniversityShanghai 200444China Center for High Pressure Science State Key Laboratory of Metastable Materials Science and TechnologyYanshan UniversityQinhuangdao 066004China

In spite of extremely high strength and hardness, the property of brittleness is tightly linked to diamond. In the deformation of diamond at room temperature, the plasticity of the diamond is normally considered hard to occur because of the domination of catastrophic brittle fracture. Herein, we employed in-situ transmission electron microscopy to reveal the diamond roomtemperature plastic behavior, and compared it with a recent report(Adv. Mater. 2020, 1906458) on transformation-induced room-temperature plasticity of diamond nanopillars. Our present in-situ uniaxial compression tests in sub-micron-sized diamond pillars indicate that the plasticity in diamond is carried out by dislocations slipping instead of phase transformation and the initiation of plasticity highly depends on the stress state. On the other hand, we noted that a high proportion of amorphous surface layer in the diamond pillars with a diameter of less than 20 nm may be a significant factor leading to the plasticity.

关键词： diamond plasticity dislocation in-situ transmission electron microscopy

Self-assembling nacre-like high-strength and extremely tough polymer composites with new toughening mechanism

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Journal of Materials Science & Technology 2023年第5期136卷 236-244页

作者： Yu bu Xu Wang Xiuming bu Zhengyi Mao Zhou Chen Zebiao Li Fengqian Hao Johnny C.Ho Jian Lu CityU-Shenzhen Futian Research Institute Shenzhen 518045China Centre for Advanced Structural Materials City University of Hong Kong Shenzhen Research InstituteGreater Bay Joint DivisionShenyang National Laboratory for Materials Science8 Yuexing 1st RoadShenzhen Hi-Tech Industrial ParkNanshan DistrictShenzhen 518000China MOE Key Laboratory of Impact and Safety Engineering Ningbo UniversityNingbo 315211China Department of Materials Science and Engineering City University of Hong KongHong Kong SAR 999077China Department of Mechanical Engineering City University of Hong KongHong Kong SAR 999077China

Achieving high strength,deformability and toughness in polymers is important for practical industrial *** has remained challenging because of the mutually opposing effects of improvements to each of these ***,a self-assembling nacre-like polymer composite is designed to achieve ex-tremely tough with increasing *** special design significantly improved polymer’s mechanical properties,including an ultra-high fracture strain of 1180%,a tensile strength of 55.4 MPa and a toughness of 506.9 MJ/m^(3),which far exceed the highest values previously reported for polymer *** ex-cellent combination of properties can be attributed to a novel toughening mechanism,achieved by the synergy of the domain-limiting effect of metallic glass fragments with the strain-gradient-induced orien-tation and crystallisation within the polymer during *** approach opens a promising avenue for designing robust polymer materials in armour and aerospace engineering for a range of innovative applications.

关键词： Polymer composites Metallic glass thin film Toughness Toughening mechanism Nacre-like fracture

The effects of viscosity on circumplanetary disks

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Research in Astronomy and Astrophysics 2013年第1期13卷 71-86页

作者： De-Fu bu Hsien Shang Feng Yuan Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical ObservatoriesChinese Academy of Sciences Institute of Astronomy and Astrophysics Academia Sinica (ASIAA)

The effects of viscosity on the circumplanetary disks residing in the vicinity of protoplanets are investigated through two-dimensional hydrodynamical simulations with the shearing sheet model. We find that viscosity can considerably affect properties of the circumplanetary disk when the mass of the protoplanet Mp ~ 33 Me, where Me is the Earth＇s mass. However, effects of viscosity on the circumplanetary disk are negligibly small when the mass of the protoplanet Mp 〉 33 Me. We find that when Mp ~ 33 Me, viscosity can markedly disrupt the spiral structure of the gas around the planet and smoothly distribute the gas, which weakens the torques exerted on the protoplanet. Thus, viscosity can slow the migration speed of a protoplanet. After including viscosity, the size of the circumplanetary disk can be decreased by a factor of 〉~ 20%. Viscosity helps to transport gas into the circumplanetary disk from the differentially rotating circumstellar disk. The mass of the circumplanetary disk can be increased by a factor of 50% after viscosity is taken into account when Mp ~ 33 Me. Effects of viscosity on the formation of planets and satellites are briefly discussed.

关键词： accretion accretion disks -- hydrodynamics -- planets and satellites:formation -- solar system: formation

基于《国际功能、残疾和健康分类》评价中国智能化辅盲设备的补偿功能

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中国组织工程研究 2025年第17期29卷 3650-3656页

作者：卜楠杨祎铖宋贝贝柏开祥杜芸芸武汉体育学院湖北省武汉市430079 运动健康智能装备湖北省工程研究中心湖北省武汉市430079

背景:辅盲设备及技术的应用是当今视力障碍人群常用的干预手段,可提高日常生活活动的参与及工作学习能力,帮助其回归家庭、回归社会。数字信息和智能化时代下辅盲设备的形式、技术和功能各有不同,其分类目前暂未能得到有效统一的讨论和... 详细信息

背景:辅盲设备及技术的应用是当今视力障碍人群常用的干预手段,可提高日常生活活动的参与及工作学习能力,帮助其回归家庭、回归社会。数字信息和智能化时代下辅盲设备的形式、技术和功能各有不同,其分类目前暂未能得到有效统一的讨论和评价。目的:基于《国际功能、残疾和健康分类》评价国内视力障碍人群智能化辅盲设备的补偿功能。方法:通过计算机检索中国知网、维普和万方数据库2013-01-01/2023-12-31收录的相关文献。基于《国际功能、残疾和健康分类》理论模式和框架结构,应用术语结构和编码程序归纳相关视力障碍评估类目,整理与分析国内视力障碍的智能化辅盲设备补偿功能研究与分类。结果与结论:①共纳入197篇文献:其中身体功能1篇,包含b2(b210);身体结构1篇,包含s2(s220);活动与参与共119篇,包含d1(10篇,d110、d115、d120、d140、d166),d3(4篇,d315、d325、d345、d360),d4(102篇,d465、d470),d8(3篇,d820、d825);环境因素共76篇,包含e1(72篇,e115、e120、e125、e130、e140、e150、e155、e160),e2(4篇,e210、e240);②基于《国际功能、残疾和健康分类》的视力障碍智能化辅盲设备补偿功能研究分类包含4个部分、8个分类、25个类目,领域涉及身体补偿类、生活用品类、教育学习类、出行导盲类、布局规划类。

关键词：国际功能、残疾和健康分类视力障碍辅盲设备智能化人工智能功能分类评价

人脐带间充质干细胞来源外泌体治疗SD大鼠骨质疏松性股骨骨折

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中国组织工程研究 2025年第31期29卷 6634-6641页

作者：卜宪敏梁迪张斌徐英杰丁豪吴彬田荣华济宁市第一人民医院病理科山东省济宁市272067 济宁医学院临床医学院山东省济宁市272067 济宁医学院附属医院检验科山东省济宁市272067 济宁医学院附属医院创伤骨科山东省济宁市272067

背景:人脐带间充质干细胞来源外泌体已广泛用于骨修复和重建研究,能显著促进成骨和血管生成。目的:探究人脐带间充质干细胞来源外泌体治疗骨质疏松性骨折的机制。方法:采用组织块培养法提取人脐带间充质干细胞及超速离心法提取人脐带间... 详细信息

背景:人脐带间充质干细胞来源外泌体已广泛用于骨修复和重建研究,能显著促进成骨和血管生成。目的:探究人脐带间充质干细胞来源外泌体治疗骨质疏松性骨折的机制。方法:采用组织块培养法提取人脐带间充质干细胞及超速离心法提取人脐带间充质干细胞来源外泌体并进行鉴定。30只12周龄雌性SD大鼠随机分为假手术组(6只)和去势组(24只)。去势组采用经典的去势法构建骨质疏松模型,术后12周随机选取去势组6只大鼠与假手术组6只大鼠行Micro-CT及苏木精-伊红染色进行模型验证。验证骨质疏松模型构建成功后,将去势组剩余18只大鼠随机分为3组,均构建骨质疏松性股骨骨折模型,骨折端分别注射PBS(PBS组)、1.5×10^(11)particles/mL(低浓度外泌体组)、3×10^(11)particles/mL(高浓度外泌体组)外泌体。骨折术后4周行影像学及组织学观察评估骨折愈合和骨组织血管生成情况。结果与结论:①大体标本观察:与PBS组相比,外泌体组骨折愈合速度明显增快,骨折端骨痂生成量显著增加;②X射线片评分:外泌体组显著高于PBS组,差异有显著性意义(P<0.05);③Micro-CT三维成像:与PBS组相比,外泌体组骨折愈合加快,骨痂生成量显著增加;外泌体组骨体积分数显著高于PBS组,差异有显著性意义(P<0.01);④苏木精-伊红染色和Masson染色:与PBS组相比,外泌体组有更多的骨小梁生成,有更多的新生骨组织生长;⑤免疫组织化学染色:与PBS组相比,外泌体组骨钙素与CD31的表达更加显著;高浓度外泌体组较低浓度外泌体组新生血管密度更大,骨痂生成量更多,骨折愈合增快,呈现浓度依赖性。结果表明,人脐带间充质干细胞来源外泌体可通过促进血管生成和成骨,最终促进骨质疏松性骨折修复,其机制可能与CD31和骨钙素表达增加有关。

关键词：骨质疏松性骨折人脐带间充质干细胞外泌体骨折愈合骨钙素 CD31

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Thermo-economic Investigation of an Enhanced Geothermal System Organic Rankine Cycle and Combined Heating and Power System

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Acta Geologica Sinica(English Edition) 2021年第6期95卷 1958-1966页

作者： WANG Lingbao bu Xianbiao LI Huashan Guangzhou Institute of Energy Conversion Chinese Academy of SciencesGuangzhou 510640China CAS Key Laboratory of Renewable Energy Guangzhou 510640China

As a potentially viable renewable energy, Enhanced Geothermal Systems(EGSs) extract heat from hot dry rock(HDR) reservoirs to produce electricity and heat, which promotes the progress towards carbon peaking and carbon neutralization. The main challenge for EGSs is to reduce the investment cost. In the present study, thermo-economic investigations of EGS projects are conducted. The effects of geofluid mass flow rate, wellhead temperature and loss rate on the thermo-economic performance of the EGS organic Rankine cycle(ORC) are studied. A performance comparison between EGS-ORC and the EGS combined heating and power system(CHP) is presented. Considering the CO_(2)emission reduction benefits, the influence of carbon emission trading price on the levelized cost of energy(LCOE) is also presented. It is indicated that the geofluid mass flow rate is a critical parameter in dictating the success of a project. Under the assumed typical working conditions, the LCOE of EGS-ORC and EGS-CHP systems are 24.72 and 16.1 cents/k Wh, respectively. Compared with the EGS-ORC system, the LCOE of the EGS-CHP system is reduced by 35%. EGS-CHP systems have the potential to be economically viable in the future. With carbon emission trading prices of 12.76 USD/ton, the LCOE can be reduced by approximately 8.5%.

关键词： enhanced geothermal system organic Rankine cycle combined heating and power system thermo-economic investigation carbon emission reduction

Preparation of Cu-MgO Catalysts via Urea-nitrate Combustion Method and Their Catalytic Performance in Vapor Phase Hydrogenation of Furfural

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Chemical Research in Chinese Universities 2017年第3期33卷 442-446页

作者： WANG Lieheng bu Tiantong WANG Zhenlu Key Laboratory of Surface and Interface Chemistry of Jilin Province College of Chemistry Jilin University Changchun 130021 P. R. China

A series of Cu-MgO catalysts was prepared via a urea-nitrate combustion method, and their catalytic per-formance was examined in the vapor phase hydrogenation of furfural. Characterization results showed that the amount of urea had important effects on the surface area, Cu dispersion and crystallite size of the catalysts. The Cu-MgO catalyst with a Cu loading of 12.1%（mass fraction） showed higher furfural conversion than the catalyst prepared by coprecipitation. The high activity was attributed to the higher dispersion of Cu on the catalyst surface. These results suggest that the combustion method is an efficient and simple route for the preparation of high activity Cu-MgO catalysts for furfural hydrogenation.

关键词： Furfural Furfuryl alcohol Hydrogenation Cu-MgO catalyst Combustion