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Science China(Information Sciences) 2024年第9期67卷 263-279页

作者： Yunkai DENG Yongwei ZHANG zhimin ZHANG Wei WANG Heng ZHANG Department of Space Microwave Remote Sensing System Aerospace Information Research InstituteChinese Academy of Sciences

Waveform diversity(WD) represents a dynamic and transformative technology widely used in radar systems to enhance sensitivity and discrimination capabilities. Recently, WD techniques have been extensively explored for their potential ambiguity suppression within synthetic aperture radar(SAR) *** these, the alternate transmitting mode combined with orthogonal waveforms emerges as a particularly promising solution. This study focuses on optimizing the power spectrum density(PSD) of signals to design and generate an orthogonal waveform pair that achieves both a low cross-correlation-to-autocorrelation ratio(CAR) and satisfactory imaging performance. Initially, we construct a fractional programming model with convex constraints to minimize the CAR. To address this challenge, we introduce an iterative optimization procedure for the PSD variable, which sequentially reduces the CAR. Each optimization step can be efficiently solved using a quadratically constrained quadratic program, ensuring that the resulting computational complexity remains low. Building on the optimized PSD, we established a parametric piecewise linear model to generate an orthogonal waveform pair. This model not only maintains a low CAR but achieves satisfactory imaging performance in real-time applications. Consequently, this orthogonal waveform pair effectively suppresses range ambiguity in SAR systems. Finally, we demonstrated the practicability and effectiveness of the proposed orthogonal waveforms through detailed simulation experiments, specifically targeting ambiguity suppression in conventional quad-polarization SAR systems.

关键词： synthetic aperture radar (SAR) waveform diversity (WD) ambiguity suppression orthogonal waveform fractional programming power spectrum density (PSD)

EFFICIENT SPECTRAL METHODS FOR EIGENVALUE PROBLEMS OF THE INTEGRAL FRACTIONAL LAPLACIAN ONABALLOFANYDIMENSION

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Journal of Computational Mathematics 2024年第4期42卷 1032-1062页

作者： Suna Ma Huiyuan Li zhimin Zhang Hu Chen Lizhen Chen College of Science Nanjing University of Posts and TelecommunicationsNanjingChina State Key Laboratory of Computer Science/Laboratory of Parallel Computing Institute of SoftwareChinese Academy of SciencesBeijingChina Department of Mathematics Wayne State UniversityDetroitUSA School of Mathematical Sciences Ocean University of ChinaQingdaoChina Beijing Computational Science Research Center BeijingChina

An efficient spectral-Galerkin method for eigenvalue problems of the integral fractional Laplacian on a unit ball of any dimension is proposed in this *** symmetric positive definite linear system is retained explicitly which plays an important role in the numerical *** a sharp estimate on the algebraic system's condition number is established which behaves as N4s with respect to the polynomial degree N,where 2s is the fractional derivative *** regularity estimate of solutions to source problems of the fractional Laplacian in arbitrary dimensions is firstly investigated in weighted Sobolev *** the regularity of eigenfunctions of the fractional Laplacian eigenvalue problem is readily ***,rigorous error estimates of the eigenvalues and eigenvectors are *** experiments are presented to demonstrate the accuracy and efficiency and to validate the theoretical results.

关键词： Integral fractional Laplacian Spectral method Eigenvalue problem Regularity analysis Error estimate

Optimizing piezoelectric performance of complex perovskite through increasing diversity of B-site cations

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Journal of Materials Science & Technology 2024年第3期170卷 78-86页

作者： Mengdi Cheng Dongyan Zhang yangxi Yan zhimin Li Pangpang Wang Ri-ichi Murakami School of Advanced Materials and Nanotechnology Xidian UniversityXi’an 710126China Nanomaterials Group Institute of SystemInformation Technologies and Nanotechnologies(ISIT)Fukuoka Industry-Academia Symphonicity(FiaS)4-1 KyudaishinmachiNishi-kuFukuoka 819-0388Japan School of Mechanical Engineering Chengdu UniversityChengdu 610106China

Piezoelectric materials with unique properties are hugely appealing for high sensitivity sensors and ultrasonic ***,Pb(Ni_(1/3)Nb_(2/3))O_(3)-Pb(Yb_(1/2)Nb_(1/2))O_(3)-PbTiO_(3)piezoelectric system was designed and investigated in *** optimized piezoelectric response(d_(33)=826 pC/N,d_(33)∗=1017 pm/V)together with good temperature stability and negligible performance degradation up to 10^(6) cycles was achieved in 0.58PNN-0.10PYN-0.32PT *** analysis revealed the amplification of intrinsic and extrinsic contributions in MPB region due to more spontaneous polarization orientations and an increase in chemical disorder of system after the introduction of *** origin of high piezoelectric response was investigated through the combination of scanning electron microscopy and piezoresponse force *** diversity of B-site cations was shown to enhance local structural heterogeneity,weaken long-range ferroelectric ordered domains,and lower free energy barrier via the formation of nanodomain configuration that promoted polarization rotation,thereby improving piezoelectric properties of the ***,it is suggested that increasing the diversity of B-site cations is an effective strategy for achieving outstanding piezoelectric performance.

关键词： PNN-PYN-PT ceramics Piezoelectricity enhancement Relaxation behavior Domain structure

Nursing Care of Infliximab for Injection in Crohn’s Disease

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yangtze Medicine 2024年第2期8卷 41-47页

作者： Liu yang Xiaomei Cai zhimin Tian The First Affiliated Hospital of yangtze University Jingzhou China

Objective: To summarize the nursing experience of infliximab injection in the treatment of Crohns disease. Methods: 25 patients with Crohns disease admitted to our hospital from November 2017 to February 2024 were treated with infliximab. The therapeutic effect and adverse drug reactions were observed, nursing intervention was given, and follow-up was performed at 2 weeks, 6 weeks after the first treatment and every 2 months after the treatment cycle. According to Crohns disease activity index (CDAI) score, 23 cases with 4 were classified as remission stage and 2 cases with 6 were classified as mild activity stage. Infliximab-treated Crohns patients had a good prognosis and minor adverse reactions. A correct grasp of the basic knowledge of the drug, standardized operation, attention to the psychological state of the patient, close observation of the change of the patients condition, and predictability of the treatment of adverse drug reactions are the guarantee of smooth treatment.

关键词： Crohn’s Disease Infliximab Adverse Reactions Nursing

Theoretical investigation of chirality control in single-walled carbon nanotube growth

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Theoretical investigation of chirality control in single-wal...

Artificial intelligence in physiological characteristics recognition for internet of things authentication

中国化学会第十二届全国量子化学会议

作者： Wang Qiang yang zhimin Shan Xiaoye Zhu Hongjun College of Science Nanjing Tech University

Single walled carbon nanotubes（SWCNTs）are one of hot and cutting-edge topics for research and applications in nanoscience and *** synthesis of SWCNTs with identical chirality or homogenous properties is still a big ***,our work focuses on the systematical investigation chirality control mechanism of SWCNT growth by using density functional theory *** aim to:（1）simulate the growth of SWCNTs without any catalysts under different synthesis conditions,which should reveal chirality control and preferential growth mechanism for a series of higher chiral angle nanotubes by exploring different reaction paths as well as their precise potential energy surface,activation energy barrier,and so on;（2）simulate the growth of various chiral growing carbon caps and tubes on different types of catalytic clusters including metal,metal carbide,and semiconductor,which should reveal hidden crucial roles played by catalytic clusters in chirality control and preferential growth mechanism of specific chiral SWCNTs by investigating interfacial interactions,charge transfer,reactivity,and so on;（3）investigate and rationalize other crucial factors influencing the chirality control growth of SWCNTs including various additive gases such as hydrogen,oxygen,and so ***,a rational solution will be put forward for the chirality control synthesis and applications of SWCNTs.

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来源： cnki会议评论

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Digital Communications and Networks 2024年第3期10卷 740-755页

作者： zhimin Zhang Huansheng Ning Fadi Farha Jianguo Ding Kim-Kwang Raymond Choo School of Computer and Communication Engineering University of Science and Technology BeijingBeijing100083China Beijing Engineering Research Center for Cyberspace Data Analysis and Applications Beijing100083China Faculty of Informatics Engineering Aleppo UniversityAleppoSyria Department of Computer Science Blekinge Institute of Technology37179KarlskronaSweden Department of Information Systems and Cyber Security University of Texas at San AntonioSan AntonioTX78249-0631USA

Effective user authentication is key to ensuring equipment security,data privacy,and personalized services in Internet of Things(IoT)***,conventional mode-based authentication methods(e.g.,passwords and smart cards)may be vulnerable to a broad range of attacks(e.g.,eavesdropping and side-channel attacks).Hence,there have been attempts to design biometric-based authentication solutions,which rely on physiological and behavioral *** characteristics need continuous monitoring and specific environmental settings,which can be challenging to implement in ***,we can also leverage Artificial Intelligence(AI)in the extraction and classification of physiological characteristics from IoT devices processing to facilitate ***,we review the literature on the use of AI in physiological characteristics recognition pub-lished after *** use the three-layer architecture of the IoT(i.e.,sensing layer,feature layer,and algorithm layer)to guide the discussion of existing approaches and their *** also identify a number of future research opportunities,which will hopefully guide the design of next generation solutions.

关键词： Physiological characteristics recognition Artificial intelligence Internet of things Biological-driven authentication

SiC的添加对AlN/Mo/SiC复合陶瓷的制备和性能影响探究

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稀有金属 2011年第6期35卷 904-908页

作者：董茜杨志民北京有色金属研究总院先进电子材料研究所北京100088

以氮化铝(AlN),钼(Mo),碳化硅(SiC)为原料,采用放电等离子烧结的方式,在1700℃,30 MPa制备出致密度高达98.5%的SiC添加的AlN/Mo复合陶瓷。采用XRD,FESEM,Agilent4284型LCR自动测试仪,网络分析仪及激光导热仪对样品的微观形貌,导电性能,... 详细信息

以氮化铝(AlN),钼(Mo),碳化硅(SiC)为原料,采用放电等离子烧结的方式,在1700℃,30 MPa制备出致密度高达98.5%的SiC添加的AlN/Mo复合陶瓷。采用XRD,FESEM,Agilent4284型LCR自动测试仪,网络分析仪及激光导热仪对样品的微观形貌,导电性能,介电性能和热导率进行了测试分析。研究结果表明:采用放电等离子烧结工艺,在较低的温度下可以制备出组织致密均匀的AlN/Mo/SiC复合材料,但随着SiC添加含量的增加,当SiC的体积含量占到总体的60%时,复合材料的致密度又会出现明显的下降。添加SiC后,相对于AlN/Mo复合陶瓷,复合材料的电阻率得以进行有效的控制,不会出现非线性突变—渗流现象,而是在一定的范围内缓慢下降。在26.5～40.0 GHz下复合材料的介电常数和介电损耗均随着SiC含量的增加而增加。复合材料的热导率随着SiC含量的增加而下降:当致密度高于某临界值时,其热导率主要受SiC含量及其分布状态的影响,随着SiC含量的增加呈缓慢下降的趋势;而当致密度低于临界值后,致密度成为热导率的决定性因素,使得复合材料的热导率随着致密度的降低快速下降。

关键词： AlN/Mo/SiC复合陶瓷放电等离子烧结电阻率介电性能热导率

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对当前美洲自由贸易区谈判进程的分析

拉丁美洲研究 2005年第3期27卷 57-60页

作者：杨志敏中国社会科学院拉丁美洲研究所北京100007

美洲自由贸易区没有按照预定计划于2005年1月1日如期建立。而且,一些权威人士认为2005年也难以完成有关美洲自由贸易区的谈判进程。与此同时,似乎巧合的是世界贸易组织多边自由贸易谈判的多哈回合,也未能在规定的2005年1月完成。多哈回... 详细信息

美洲自由贸易区没有按照预定计划于2005年1月1日如期建立。而且,一些权威人士认为2005年也难以完成有关美洲自由贸易区的谈判进程。与此同时,似乎巧合的是世界贸易组织多边自由贸易谈判的多哈回合,也未能在规定的2005年1月完成。多哈回合与美洲自由贸易区谈判进程紧密相连,在某种意义上相互影响,互为作用。而在美洲自由贸易区谈判陷入“僵局”的时候,美洲地区、尤其是南美区域一体化进程却没有停止脚步,并且呈现新的发展趋势。

关键词：美洲自由贸易区区域一体化

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浙江省农民工体育现状与对策研究

成都体育学院学报 2006年第5期32卷 38-39,49页

作者：杨志敏温州大学体育学院浙江温州325000

采用问卷调查法,对浙江省7个城市农民工体育活动的现状进行调查。结果表明:虽然农民工对体育有一定认识,但是由于体育设施不便利、闲暇时间少、工作强度大导致他们参与锻炼内容单一、技术含量低,总体上处于较低的水平。建议加强政府组... 详细信息

采用问卷调查法,对浙江省7个城市农民工体育活动的现状进行调查。结果表明:虽然农民工对体育有一定认识,但是由于体育设施不便利、闲暇时间少、工作强度大导致他们参与锻炼内容单一、技术含量低,总体上处于较低的水平。建议加强政府组织领导,加大宣传健身力度、广度,改善体育设施,规范社会体育指导员制度。

关键词：浙江农民工体育建议

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