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Comparative Study of 3D-Printed Porous Titanium Alloy with Rod Designs of Three Different Geometric Structures for Orthopaedic Implantation

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Acta Metallurgica Sinica(English Letters) 2024年第1期37卷 54-66页

作者： Jiaxin Li haozhang Zhong Bojun Cao Zhaoyang Ran Jia Tan Liang Deng yongqiang hao Jinglong Yan Department of Orthopedics The Second Affiliated Hospital of Harbin Medical UniversityHarbin150001China Shanghai Engineering Research Center of Innovative Orthopaedic Instruments and Personalized Medicine Shanghai Ninth People’s HospitalShanghai Jiao Tong University School of MedicineShanghai200011China Institute of Materials Modification and Modeling Shanghai Jiao Tong UniversityShanghai200240China

Porous titanium alloy is currently widely used in clinical treatment of orthopaedic diseases for its lower elastic modulus and ability to integrate with bone tissue.At the micro-level,cells can respond to different geometries,and at the macro-level,the geometric design of implants will also affect the biological function of cells.In this study,three kinds of porous scaffolds with square,triangular and circle rod shapes were designed and 3D printed.This study observed the proliferation and differentiation of MC3T3-E1 cells during surface culture of the three types of scaffolds.It also evaluated the characteristics of the three scaffolds by means of compression tests and scanning electron microscopy to provide a reference for the design of porous titanium alloy implants for clinical applications.The trends of cell proliferation and gene expression between the three types of scaffolds were observed after treatment with two inhibitors.The results show that the square rod porous scaffolds have the best proliferative and osteogenic activities,and these findings may be due to differences in piezo-type mechanosensitive ion channel component 1(Piezo1)and Yes-associated protein(YAP)expression caused by the macro-geometric topography.

关键词： Porous titanium scaffolds Geometric morphology Cell proliferation Structural design

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Hour-to-hour variability of the ionosphere: An application of the classical multidimensional scaling method

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Science China Earth Sciences 2015年第7期58卷 1243-1250页

作者： SHI hao ZHANG DongHe hao yongqiang XIAO Zuo Department of Geophysics Peking University

The classical multidimensional scaling(MDS) method is introduced and applied in the study of the hour-to-hour ionospheric variability based on the ionospheric fo F2 observed at three ionosonde stations in East-Asia in 2002 and 2007. Results from the matrix eigen decompositions indicate that the annual part of the ionospheric variation is large in middle latitude and solar maximum period(2002) while low in the low latitude and solar minimum period(2007). The connectivity maps of the hour-to-hour ionospheric variability based on MDS method show some common diurnal features. The ionospheric connectivity between adjacent hours near noon hours and near midnight hours is high. The ionospheric connectivity between adjacent hours near sunrise hours and near sunset hours is poor, especially for the sunrise hours. Also there are latitudinal and solar activity dependences in this kind of connectivity. These results revealed from the ionospheric connectivity maps are useful physically and in practice for the ionospheric forecasting on the hour-to-hour scale.

关键词：电离层预报小时应用多维太阳活动地图显示特征分解 DS方法

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Analysis of the ionospheric variability based on wavelet decomposition

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Science China(Technological Sciences) 2015年第1期58卷 174-180页

作者： SHI hao ZHANG DongHe LIU YuMei hao yongqiang Department of Geophysics Peking University National Key Laboratory of Electromagnetic Environment China Research Institute of Radio Wave Propagation

In this work,the ionospheric variability is analyzed by applying the wavelet decomposition technique to the noontime fo F2,F10.7,interplanetary magnetic field(IMF)Bz,Ap,and lower thermospheric temperature at pressure of 10?4 h Pa in 2002.Results show that the variance of periodic oscillations in the ionosphere is largest in the 2–4-day period and declines with the increase of the period.The maximum variance of the periodic oscillations in solar irradiation is in the 16–32-day period.For geomagnetic activities,most of the variance is about equally distributed on intervals of periods shorter than 32 days.Variance distributions of IMF Bz and lower thermospheric temperature are similar to those of the ionosphere.They show the maximum in the 2–4-day period and decline with the increase of the period.By analyzing the distributions of the variances,the potential connections between the ionosphere and the external sources are discussed.

关键词：小波分解电离层周期振荡分解技术星际磁场太阳辐射地磁活动均匀分布

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Ionospheric absorption and planetary wave activity in East Asia sector

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Science China(Technological Sciences) 2012年第5期55卷 1264-1272页

作者： hao yongqiang ZHANG DongHe Institute of Space Physics and Applied Technology Peking UniversityBeijing 100871China State Key Laboratory of Space Weather Chinese Academy of SciencesBeijing 100190China

In this paper, we focus on ionospheric absorption in the East Asia sector, and look for manifestations of atmospheric influences in this area. First, a 4-year historical record of absorption measurement at Beijing is presented. This record was obtained by a sweep frequency technique, in which 27-days periodic variation of the absorption level was found to be dominant, appearing in most seasons except winters. Instead, unusual enhancements of the absorption level appeared in winters (winter anomaly), at the meantime the level varied with periods mainly in the range of 8-12 days. Comparing to 27-days period from the Sun, the shorter period oscillations should be related to planetary wave activities in lower atmosphere. Second, fmin data from 5 mid-latitude ionosondes in Japan were used as an indirect but long-term measurement. With the fmin data covering two solar cycles, disturbances with various periods were found to be active around solar maximum years, but the 8-12 days oscillations always existed in winter, showing seasonal dependence instead of connection to solar activity. These results given in this paper demonstrate seasonal and solar cycle-dependent features of the ionospheric absorption in East Asia sector, and confirm the existence of influence from atmosphere-ionosphere coupling in this area, as well as the relationship between ionospheric winter anomaly and planetary wave activity.

关键词：大气电离层吸收测量行星波东亚太阳活动周期短周期振荡周期性变化季节性

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Particle bursts in the inner radiation belt related to global lightning activity

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Science China(Technological Sciences) 2013年第11期56卷 2658-2667页

作者： WU Fei hao yongqiang ZHANG DongHe Institute of Space Physics and Applied Technology Peking University State Key Laboratory of Space Weather Chinese Academy of Sciences

Particle bursts(PBs),the phenomena characterized by short-term increases of particle counting rates(CRs),were observed by space-borne radiation belt particle detectors.With the electron CR data obtained by National Oceanic and Atmospheric Administration(NOAA)-18 satellite,the occurrence of PBs in the inner belt(1 L 2 and B 20.5 T)were derived for years2006–2011.The monthly occurrence number of PBs exhibits a strong maximum in northern summer(May–August).In association with global lightning data,the seasonal occurrence of PBs is found to be consistent with the lightning activity,especially if only lightning flashes at latitudes>20°are taken into account.The positive correlation between PBs and mid-latitude lightning discharges indicates the role of lightning-induced whistler waves,and is consistent with the expected pitch-angle scattering by wave-particle interactions.The contribution of lightning is so significant that it forms a non-negligible seasonal background of PBs.If one connects PBs to seismoelectromagnetic emissions(SEME)in attempt to find the earthquake precursor,the lightning background needs to be considered with great care.

关键词：粒子探测器闪电活动辐射带 PBS NOAA 雷电活动正相关性闪电放电

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Ultra low frequency waves impact on radiation belt energetic particles

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Science China(Technological Sciences) 2009年第12期52卷 3698-3708页

作者： ZONG QiuGang hao yongqiang WANG YongFu Institute of Space Physics and Applied Technology Peking UniversityBeijing 100871China

One of the most fundamental important issues in the space physics is to understand how solar wind energy transports into the inner magnetosphere.Ultra low frequency(ULF)wave in the magnetosphere and its impact on energetic particles,such as the wave-particle resonance,modulation,and particle acceleration,are extremely important topics in the Earth’s radiation belt dynamics and solar wind― magnetospheric coupling.In this review,we briefly introduce the recent advances on ULF waves study. Further,we will explore the density structures and ion compositions around the plasmaspheric boundary layer(PBL)and discuss its possible relation to the ULF waves.

关键词： radiation belt particle ULF wave wave-particle interaction(WPI) energetic particles acceleration plasmaspheric boundary layer oxygen ions

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Case study of ionospheric fluctuation over mid-latitude region during one large magnetic storm

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Science China(Technological Sciences) 2012年第5期55卷 1198-1206页

作者： ZHANG DongHe MO XiaoHua A Ercha hao yongqiang Department of Geophysics Peking UniversityBeijing 100871China State Key Laboratory of Space Weather Chinese Academy of SciencesBeijing 100080China College of Physics and Electronic Engineering Guangxi University for NationalitiesNanning 530006China

From Nov. 6 to 10, 2004, a large number of solar events occurred, which triggered many solar flares and coronal mass ejections (CMEs). These CMEs caused two large geomagnetic storms and continuous energy proton events. During this period, one large positive ionospheric storm happened over the East-Asian region on Nov. 8, 2004. On Nov. 10, 2004, a strong spread-F was observed by the ionosonde located in the mid-latitude region of East China and Japan, and the ionospheric fluctuation over the ionosonde stations derived from GPS observation was also obvious. In this report, the characteristics of the spatial distribution of the ionosphere fluctuation and its temporal evolution are studied using the parameter of the rate of total electron content (ROT) derived from dual-frequency GPS measurement. Strong fluctuating activity of the ionosphere was found over the mid-latitude region in the southern and northern hemispheres between longitudes of 100°E and 180°E during the magnetic storm period on Nov. 10, 2004, and a regular movement of the disturbing region was observed. In the end, the reason of the ionospheric fluctuation during this magnetic storm is analyzed.

关键词：中纬度地区电离层暴波动磁暴日冕物质抛射案例空间分布特征 GPS观测

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乡村关系网络何以助力政策执行——基于冀北“煤改电”政策执行的个案研究

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农业经济问题 2024年第2期 109-120页

作者：张新文郝永强南京农业大学公共管理学院南京210095

政策执行是政策主体与政策目标群体的交互过程,其不仅取决于科层体系内公共政策的上下流转,而且仰赖于科层系统外政策目标群体的行为遵循。不同于城市社会,乡村社会中的政策执行往往内嵌于关系网络之中。因此,本文将“社会关系网络”纳... 详细信息

政策执行是政策主体与政策目标群体的交互过程,其不仅取决于科层体系内公共政策的上下流转,而且仰赖于科层系统外政策目标群体的行为遵循。不同于城市社会,乡村社会中的政策执行往往内嵌于关系网络之中。因此,本文将“社会关系网络”纳入分析框架,对政策目标群体内在关系结构之于诱致性公共政策执行的潜在机理进行理论解析,以解释二者之间的逻辑关联。在乡村社会,关系网络助力诱致性公共政策执行的内在机理主要表现为:熟人关系网络及建构于此的人际信任在意见领袖的作用下不断向政策信任转化,并在此基础上通过信任关系所内含的信息扩散机制与信息补偿效应助推政策目标群体的行为遵循,从而推进政策落实与政策变现。该机理始于对诱致性公共政策执行过程的分析,建立在政策预期效用与乡村社会熟人关系网络的基础之上,并以乡村精英的治理转型为其运作的关键支撑。

关键词：政策执行关系网络人际信任政策信任意见领袖

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The variation of the estimated GPS instrumental bias and its possible connection with ionospheric variability

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Science China(Technological Sciences) 2014年第1期57卷 67-79页

作者： ZHANG DongHe SHI hao JIN YaQi ZHANG Wei hao yongqiang XIAO Zuo Department of Geophysics Peking University Department of Geodesy and Geomatics Engineering University of New Brunswick Fredericton 4400 New Brunswick Canada

Based on the analysis of the satellite DCB data estimated by our method and the Center for Orbit Determination in Europe(CODE)from 1999 to 2011,the features of the temporal variation of differential code biases(DCB)are studied.Summarily,there are three types of variations in DCB on different time scales.The first one is the day-to-day variation that exhibits more obviously in solar maximum years.The second one is the variation with about one year periodic variation that behaves more obviously from 1999 to 2004.The last one is the monotonously descending tendency from 1999 to 2010.Considering the basic ionospheric approximation in DCB estimation method,the features of the variability of the ionospheric morphology from 1999to 2010 are also displayed based on the ionospheric characteristic parameters.It can be concluded that the day-to-day and annual variation of the estimated global positioning system(GPS).DCB is related to the ionospheric variability.The variation of DCBs on solar cycle time scale includes the real hardware DCBs and pseudo-DCBs induced by ionospheric variation.No doubt,these kinds of"pseudo"variations of DCB will affect the precision of ionospheric total electron content(TEC)derived from the GPS data.In addition,this study is helpful for evaluating the influence of ionospheric weather on TEC derivation and is also useful for developing one estimation method of DCB with more stability and precision through introducing a more practical ionospheric model.

关键词：电离层模型 GPS数据估计方法仪器偏差时间尺度变化连接太阳活动峰年全球定位系统

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Energetic particle radiations measured by particle detector on board CBERS-1 satellite

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Chinese Science Bulletin 2007年第5期52卷 665-670页

作者： hao yongqiang XIAO Zuo ZOU Hong ZHANG DongHe Department of Geophysics Peking University Beijing 100871 China Key Laboratory of Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing 100080 China

Using the data measured by energetic particle detector on board CBERS-01 and -02 for the past five years, statistics was made to show the general features of MeV electrons and protons along a solar synchronous orbit at an altitude of 780 km. This height is in the bottom region of the Earth's radiation belts. Detectors are inside the satellite cabinet and such continuous monitoring of particle radiation environment inside a satellite has seldom conducted so far. After a proper and careful treatment, it is indicated that the data inside satellite are well correlated with the radiation environment outside. Be-sides the agreement of the general distribution characteristics of energetic electrons and protons with similar observations from other satellites, attention is particularly paid to the disturbed conditions. Variations of particle fluxes are closely related with solar proton events, in general, electron fluxes of outer belt are well correlated with Dst index after three days' delay while the electron injection occurred almost at the same day during great magnetic storms. It is confirmed that both energetic electrons and protons appear in the Polar Cap region only after the solar proton events.

关键词： CBERS-01 地球资源卫星高能粒子辐射粒子探测器测量空间环境辐射带

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