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Optimal AP Deployment in Cell-Free Massive MIMO Systems with LoS/NLoS Transmissions:A Stochastic Geometry Approach

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China Communications 2024年第9期21卷 146-158页

作者： Jiang ling Zhang Qi Zhu Hongbo Jiangsu Key Laboratory of Wireless Communications Nanjing University of Posts and TelecommunicationsNanjing 210003China

Cell-free massive multiple-input multipleoutput(MIMO)is a promising technology for future wireless communications,where a large number of distributed access points(APs)simulta.eously serve all users over the same time-frequency *** users and APs may locate close to each other,the line-of-sight(Lo S)transmission occurs more frequently in cell-free massive MIMO ***,in this paper,we investigate the cell-free massive MIMO system with Lo S and non-line-of-sight(NLo S)transmissions,where APs and users are both distributed according to Poisson point *** tools from stochastic geometry,we derive a tight lower bound for the user downlink achievable rate and we further obta.n the energy efficiency(ee)by considering the power consumption on downlink payload transmissions and circuitry *** on the analysis,the optimal AP density and AP antenna number that maximize the ee are *** is found that compared with the previous work that only considers NLo S transmissions,the actual optimal AP density should be much smaller,and the maximized ee is actually much higher.

关键词： cell-free massive MIMO energy efficiency LoS/NLoS transmissions stochastic geometry

Toughened (Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)ta.(0.2))B_(2)–SiC composites fabricated by one-step reactive sintering with a unique SiB_(6) additive

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Journal of Advanced Ceramics 2024年第1期13卷 86-100页

作者： Wei Hao Xinzhe Lu ling Li ta. Wang Guoliang Ren Huangyue Cai Xiaofeng Zhao Dongyun Wang Na Ni Zhejiang Provincial Key Laboratory of Urban Rail Transit Intelligent Operation and Maintenance Technology&Equipment Zhejiang Normal UniversityZhejiang 321004China Key Lab of Education Ministry for Power Machinery and Engineering School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China

High-entropy diboride has been arousing considerable interest in recent ***,the low toughness and damage tolerance limit its applications as ultra-high-temperature structural *** we report that a unique SiB_(6) additive has been first incorporated as boron and silicon sources to fabricate a high-entropy boride(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)ta.(0.2))B_(2)–SiC composite though one-step boro/carbothermal reduction reactive sintering.A synergetic effect of high-entropy sluggish diffusion and SiC secondary phase reta.ded the grain growth of the(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)ta.(0.2))B_(2)–51SiC *** small grain size was beneficial to shorten the diffusion path for mass transport,thereby enhancing the relative density to~99.3%.These results in an increase of fracture toughness from~5.2 in HEBS-1900 to~7.7 MPa·m^(1/2) in HEBS-2000,which corresponded to a large improvement of 48%.The improvement was attributed to a mixed mode of intergranular and transgranular cracking for offering effective pinning in crack propagation,resulting from balanced grain boundary strength collectively affected by improved densification,solid solution strengthening,and incorporation of SiC secondary phase.

关键词： high-entropy diboride silicon hexaboride boro/carbothermal reduction reactive sintering fracture toughness

Plume-lithosphere interaction in the Comei Large Igneous Province: Evidence from two types of mafic dykes in Gyangze, south Tibet, China

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China Geology 2024年第1期7卷 80-90页

作者： Ya-ying Wang ling-sen Zeng Li-e Gao Li-long Yan ling-hao Zhao Jia-hao Gao Ying-long Di Guang-xu Li Yi-hong Tian Institute of Geology Chinese Academy of Geological SciencesBeijing 100037China National Research Center for Geoanalysis Chinese Academy of Geological SciencesBeijing 100037China China Nonferrous Meta.s(Guilin)Geology and Mining Co. LtdGuilin 541004China

Two suites of mafic dykes,T1193-A and T1194-A,outcrop in Gyangze area,southeast *** are in the area of Comei LIP and have indistinguishable field occurrences with two other dykes in Gyangze,T0902 dyke with 137.7±1.3 Ma zircon age and T0907 dyke with 142±1.4 Ma zircon age reported by Wang YY et al.(2016),indicating coeval formation *** all the four diabase dykes into consideration,two different types,OIB-type and weak enriched-type,can be ***“OIB-type”samples,including T1193-A and T0907 dykes,show OIB-like geochemical features and have initial Sr-Nd isotopic values similar with most mafic products in Comei Large Igneous Provinces(LIP),suggesting that they represent melts directly generated from the Kerguelen mantle ***“weak enriched-type”samples,including T1194-A and T0902 dykes,have Rees and trace element patterns showing withinplate affinity but have obvious Nb-ta.Ti negative *** show uniform lowerεNd(t)values(−6‒−2)and higher 87Sr/86Sr(t)values(0.706‒0.709)independent of their MgO variation,indicating one enriched mantle *** their closely spatial and temporal relationship with the widespread Comei LIP magmatic products in Tethyan Himalaya,these“weak enriched-type”samples are consistent with mixing of melts from mantle plume and the above ancient Tethyan Himalaya subcontinenta. lithospheric mantle(SCLM)in different *** weak enriched mafic rocks in Comei LIP form one special rock group and most likely suggest large scale hot mantle plume-continenta. lithosphere *** process may lead to strong modification of the Tethyan Himalaya lithosphere in the Early Creta.eous.

关键词： OIB type diabase Comei Large Igneous Province Weakly enriched diabase Plume-lithosphere interaction Nb-ta.Ti negative anomaly Kerguelen plume Geological survey engineering Tibet Plateau

Hexafluoropropylene oxide trimer acid,a perfluoroocta.oic acid alternative,induces cardiovascular toxicity in zebrafish embryos

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Journal of Environmenta. Sciences 2024年第5期139卷 460-472页

作者： Sujie Sun Li Zhang Xue Li Lu Zang ling Huang Junquan Zeng Zigang Cao Xinjun Liao Zilin Zhong Huiqiang Lu Jianjun Chen Jiangxi Engineering Laboratory of Zebrafish Modeling and Drug Screening for Human Diseases Jiangxi Key Laboratory of Developmental Biology of OrgansCenter for Clinical Research Center of the Affiliated Hospital of Jinggangshan UniversityJi’an 343009China Translational Research Institute of Brain and Brain-like Intelligence Shanghai Key Laboratory of Anesthesiology and Brain Functional ModulationDepartment of PediatricsShanghai Fourth People’s HospitalSchool of MedicineTongji UniversityShanghai 200434China Sta.e Environmenta. Protection Key Laboratory of Environmenta. Health Impact Assessment of Emerging Conta.inants School of Environmental Sciences and EngineeringShanghai Jiao Tong UniversityShanghai 200240China Department of Interventional and Vascular Surgery Affiliated Hospital of Jinggangshan UniversityJi’an 343009China Department of Internal Medicine and Hematology Affiliated Hospital of Jinggangshan UniversityJi’an 343009China

As an increasingly used alternative to perfluoroocta.oic acid(PFOA),hexafluoropropylene oxide trimer acid(HFPO-ta.has been widely detected in global water ***,little is known regarding its toxic effects on cardiovascular ***,zebrafish embryos were treated with egg water conta.ning 0,60,120,or 240 mg/L *** showed that HFPO-ta.treatment led to a significant reduction in both larval survival percenta.e and heart ***,HFPO-ta.exposure caused severe pericardial edema and elongation of the sinus venous to bulbus arteriosus dista.ce(SV-BA)in Tg(myl7:GFP)transgenic larvae,disrupting the expression of genes involved in heart development and thus causing abnormal heart *** sprouting angiogenesis was observed in the 120 and 240 mg/L exposed Tg(fli:GFP)transgenic ***-ta.treatment also impacted the mRNA levels of genes involved in the vascular endothelial growth factor(VEGF)pathway and embryonic vascular ***-ta.exposure significantly decreased erythrocyte number in Tg(gata.:DsRed)transgenic embryos and influenced gene expression associated with the heme meta.olism ***-ta.also induced oxidative stress and altered the transcriptional levels of genes related to cell cycle and apoptosis,inhibiting cell proliferation while promoting ***,HFPO-ta.exposure may induce abnormal development of the cardiovascular and hematopoietic systems in zebrafish embryos,suggesting it may not be a suita.le or safe alternative for PFOA.

关键词： Hexafluoropropylene oxide trimer acid Heart development Vascular development Hemopoiesis Zebrafish embryos

正交匹配追踪优化稀疏频散Radon变换多模式导波分离方法

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声学学报 2024年第3期49卷 371-380页

作者：郑书航陈洪磊凌非尧许凯亮他得安复旦大学信息科学与工程学院生物医学工程系上海200438 复旦大学集成芯片与系统全国重点实验室上海201203 复旦大学义乌研究院义乌322000 复旦大学工程与应用技术研究院生物医学工程技术研究所上海200433

原始频散Radon变换(DRT)方法中的有限孔径效应以及算子非正交性影响了DRT导波信号参数提取的精度,因此提出了一种稀疏频散Radon变换方法以实现更精确的导波混叠模式分离和参数估计。该方法基于导波信号的参数域稀疏性,引入正交匹配追踪... 详细信息

原始频散Radon变换(DRT)方法中的有限孔径效应以及算子非正交性影响了DRT导波信号参数提取的精度,因此提出了一种稀疏频散Radon变换方法以实现更精确的导波混叠模式分离和参数估计。该方法基于导波信号的参数域稀疏性,引入正交匹配追踪算法构造代价函数,经多次迭代在频散Radon域中获得稀疏能量谱,可精确分离阵列导波信号中的混叠模式并去噪。对不同信噪比下各模式仿真信号,稀疏DRT方法的信号重建误差较原始频散Radon变换方法下降51.1%。仿真和实验验证了所提算法在导波模式参数提取和混合模式分离方面的可靠性。

关键词：超声导波模式分离频散Radon变换正交匹配追踪

On building automation system security

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High-Confidence Computing

High-Confidence Computing 2024年第3期4卷 103-122页

作者： Christopher Morales-Gonzalez Matthew Harper Michael Cash Lan Luo Zhen ling Qun Z.Sun Xinwen Fu Department of Computer Science University of Massachusetts LowellLowell 01854USA Department of Electrical and Computer Engineering University of Central FloridaOrlando 32816USA School of Computer Science and Technology Southeast UniversityMa’anshan 243032China School of Computer Science and Engineering Anhui University of TechnologyNanjing 211189China

Building Automation Systems(BASs)are seeing increased usage in modern society due to the plethora of benefits they provide such as automation for climate control,HVAC systems,entry systems,and lighting *** BASs in use are outdated and suffer from numerous vulnerabilities that stem from the design of the underlying BAS *** this paper,we provide a comprehensive,up-to-date survey on BASs and atta.ks against seven BAS protocols including BACnet,EnOcean,KNX,LonWorks,Modbus,ZigBee,and *** studies of secure BAS protocols are also presented,covering BACnet Secure Connect,KNX Data.Secure,KNX/IP Secure,ModBus/TCP Security,EnOcean High Security and Z-Wave *** and ZigBee do not have security *** point out how these security protocols improve the security of the BAS and what issues remain.A case study is provided which describes a real-world BAS and showcases its vulnerabilities as well as recommendations for improving the security of *** seek to raise awareness to those in academia and industry as well as highlight open problems within BAS security.

关键词： Building automation system BAS protocols Security Atta.k

Effects of Additives on the Microstructure and Tribology Performance of ta.12W Alloy Micro-Arc Oxidation Coating

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 142-149页

作者：刘玲 HU Changgang CHENG Wendong 刘兴泉 School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu 610054China

Oxide ceramic coatings were fabricated on ta.ta.um alloys by micro-arc oxidation (MAO) to improve their hardness and tribological properties. The MAO coatings were manufactured in a mixed silicatephosphate electrolyte conta.ning NaF and/or EDta.(ethylene diamine tetraacetic acid). The surface morphology,cross-sectional view, chemical composition, hardness, and wear performance of the coatings were analysed. As revealed by the scanning electron microscopy, silica-rich nodules appear on the MAO coating obta.ned in the silicate-phosphate electrolyte, but the formation of nodules is inhibited with NaF and/or EDta.in the ***, they reduce the roughness and improve the compactness of the coatings, which are composed of ta.(2)O_(5),(ta. O), and ta.. A thick and hard coating is obta.ned in the NaF-conta.ning electrolyte, and the tribology performance is effectively improved. With additives, the nodule structure is deta.hed from the coating surface and dissolved in the electrolyte. By using NaF as an electrolyte additive, the abrasion performance of the MAO coating is enhanced by decreasing the nodule structure, increasing the size of micropores, and improving the coating hardness.

关键词： micro-arc oxidation ta.ta.um alloy additives tribology performance

Inherently Chiral and Symmetrical Heteroatom-Doped Zigzag-Type Hydrocarbon Belts

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CCS Chemistry 2024年第5期6卷 1198-1210页

作者： Xue-Yuan Wang Xin-Yu Zhang Shuo Tong Qing-Hui Guo Mei-ling ta. Cheng-Jun Li Mei-Xiang Wang Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology(Ministry of Education) Department of ChemistryTsinghua UniversityBeijing 100084

hydrocarbon belts due to their potential applications in carbon *** contrast,heteroatomembedded zigzag hydrocarbon belts as advanced design strategies with fascinating structures and desirable,unique properties have remained largely unexplored,and inherently chiral ones are ***,we report the synthesis of a diversity of symmetric and highly enantiopure inherently chiral O-and N-doped zigzag-type hydrocarbon belts sta.ting from strainless macrocycles based on fjord-stitching *** readily available pertriflated resorcin[6]arene underwent partial hydrolyses and intramolecular S_(N)Ar reactions to form a calix[3](9H-xanthene)derivative and a prochiral half-belt *** transformations of calix[3](9H-xanthene)into C_(3v)-symmetric molecular belts were achieved by closing the rest of the fjords with triple intramolecular S_(N)Ar reactions and Yamamoto homo coupling reactions,as well as palladiumcata.yzed intermolecular acridination reactions with primary *** prochiral half-belt underwent enantioselective desymmetrizative mono-acridination to afford an inherently chiral N,O_(4)-bridged pseudo-belt with an enantiomeric excess(ee)value of>99%under the cata.ysis of Pd(OAc)_(2)and(R)-*** closure reactions of the pseudo-belt produced diverse heteroatom-inlayed zigzag-type hydrocarbon belts of inherent ***,we showed the unique cavity structures of the belts and demonstrated interesting chiroptic properties of the inherently enantiopure chiral *** research opens the door for the exploration of novel and sophisticated symmetric and inherently chiral molecular nanobelt structures with outsta.ding physical and chemical properties,as well as potential applications.

关键词： zigzag-type molecular belt heterocycle chiroptical property fjord-stitching strategy resorcinarene

Image Restoration Using Hybrid Features Improvement on Morphological Component Analysis

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Journal of Electronic Science and Technology 2019年第4期17卷 371-381页

作者： Der-Chang Tseng Ru-Yin Wei Ching-ta.Lu ling-ling Wang the Department of Electronic Engineering National Taipei University of TechnologyTaipei 10608 Quanta.Computer Inc. Taipei 11167 the Department of Information Communication Asia UniversityTaichung 41354

Images are generally corrupted by impulse noise during acquisition and *** deteriorates the quality of *** remove corruption noise,we propose a hybrid approach to restoring a random noisecorrupted image,including a block matching 3D(BM3D)method,an adaptive non-local mean(ANLM)scheme,and the K-singular value decomposition(K-SVD)*** the proposed method,we employ the morphological component analysis(MCA)to decompose an image into the texture,structure,and edge ***,the BM3D method,ANLM scheme,and K-SVD algorithm are utilized to eliminate noise in the texture,structure,and edge parts of the image,*** results show that the proposed approach can effectively remove interference random noise in different parts;meanwhile,the deteriorated image is able to be reconstructed well.

关键词： Adaptive non-local mean(ANLM) block matching 3D(BM3D) image restoration morphological component analysis(MCA) singular value decomposition(SVD).