检索结果-南通市图书馆

A Quick Calculation Method for Radiation Pattern of Submillimeter Telescope with Deformation and Displacement

Research in Astronomy and Astrophysics 2024年第3期24卷 249-265页

作者： jia You yi-Wei Yao zheng Wang School of Automation Southeast UniversityNanjing 210096China

Radiation pattern captures the electromagnetic performance of reflector antennas,which is significantly affected by the deformation of the primary reflector due to gravity and the displacement of the secondary *** the design process of large reflector antennas,a substantial amount of time is often dedicated to iteratively adjusting structural parameters and validating electromagnetic *** improve the efficiency of the design process,we first propose an approximate calculation method of optical path difference(OPD)for the deformation of the primary reflector under gravity and the displacement of the secondary *** an OPD fitting function based on the modified Zernike polynomials is proposed to capture the phase difference of radiation over the aperture plane,based on which the radiation pattern will be obtained quickly by the aperture field integration *** experiments demonstrate the effectiveness of the proposed quick calculation method for analyzing the radiation pattern of a 10.4 m submillimeter telescope antenna at its highest operating frequency of 856 *** comparison with the numerical simulation method based on GRASP(which is an antenna electromagnetic analysis tool combining physical optics(PO)and physical theory of diffraction(PTD)),the quick calculation method reduces the time for radiation pattern analysis from more than one hour to less than two ***,the quick calculation method exhibits excellent accuracy for the figure of merit(FOM)of the radiation ***,the proposed quick calculation method can obtain the radiation pattern with high speed and *** to the time-consuming numerical simulation method(PO and PTD),it can be employed for quick analysis of the radiation pattern for the lateral displacement of the secondary reflector and the deformation of the primary reflector under gravity in the design process of a reflector antenna.

关键词： instrumentation high angular resolution-methods data analysis-methods analytical

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Icariin accelerates bone regeneration by inducing osteogenesisangiogenesis coupling in rats with type 1 diabetes mellitus

引用

World Journal of Diabetes 2024年第4期15卷 769-782页

作者： Sheng zheng Guan-Yu hu Jun-hua Li jia zheng yi-Kai Li Department of Traditional Chinese Orthopedics and Traumatology Center for Orthopedic SurgeryThe Third Affiliated Hospital of Southern Medical UniversityGuangzhou 510630Guangdong ProvinceChina School of Traditional Chinese Medicine Southern Medical UniversityGuangzhou 510515Guangdong ProvinceChina Department of Endocrinology Peking University First HospitalBeijing 100034China

BACKGROUND Icariin(ICA),a natural flavonoid compound monomer,has multiple pharmacological ***,its effect on bone defect in the context of type 1 diabetes mellitus(T1DM)has not yet been *** To explore the role and potential mechanism of ICA on bone defect in the context of *** The effects of ICA on osteogenesis and angiogenesis were evaluated by alkaline phosphatase staining,alizarin red S staining,quantitative real-time polymerase chain reaction,Western blot,and ***-related assays were conducted to investigate the relationship between osteogenesis and angiogenesis.A bone defect model was established in T1DM *** model rats were then treated with ICA or placebo and micron-scale computed tomography,histomorphometry,histology,and sequential fluorescent labeling were used to evaluate the effect of ICA on bone formation in the defect *** ICA promoted bone marrow mesenchymal stem cell(BMSC)proliferation and osteogenic *** ICA treated-BMSCs showed higher expression levels of osteogenesis-related markers(alkaline phosphatase and osteocalcin)and angiogenesis-related markers(vascular endothelial growth factor A and platelet endothelial cell adhesion molecule 1)compared to the untreated *** was also found to induce osteogenesis-angiogenesis coupling of *** the bone defect model T1DM rats,ICA facilitated bone formation and CD31hiEMCNhi type H-positive capillary ***,ICA effectively accelerated the rate of bone formation in the defect *** ICA was able to accelerate bone regeneration in a T1DM rat model by inducing osteogenesis-angiogenesis coupling of BMSCs.

关键词： Icariin Osteogenesis-angiogenesis coupling Type 1 diabetes mellitus Bone defect Bone regeneration

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Organic Brønsted Acid-Catalyzed Stereoselective Cationic RAFT Polymerization:The Effect of RAFT Agents

引用

Chinese Journal of Polymer Science 2024年第6期42卷 711-717页

作者： zheng-yi Zhang Zan Yang Yun Liao Sai-hu Liao Key Laboratory of Molecule Synthesis and Function Discovery(Fujian Province University) College of ChemistryFuzhou UniversityFuzhou350108China State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen361005China Beijing National Laboratory for Molecular Sciences Beijing100190China

The tacticity of vinyl polymers is a key factor affecting the properties of ***,organic Brønsted acids have been demonstrated as effective catalysts for the development of highly stereoselective cationic reversible addition-fragmentation chain transfer(RAFT)polymerizations of vinyl ethers,in which the use of RAFT agents could allow the control the molecular weight and tacticity of polymer products ***,the effect of RAFT agents on the tacticity-regulation remains elusive and lacks of *** this study,we synthesized four types of RAFT agents and evaluated their influence in the stereoselective cationic polymerization of isobutyl vinyl ether in the presence of PADI as a Brønsted acid catalyst,which unveils that the Z group of RAFT agents could not only affect the polydispersity of the products,but also exert a profound effect on the *** extensive screening of the RAFT agents,high stereoregularity(isotacticity,90%m)was obtained when using dithiocarbonate ester-type RAFT agents with a benzyloxy Z group.

关键词： Bronsted acid catalysis Stereoselective cationic polymerization RAFT polymerization Chain transfer agents Tacticity

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effects of two silicone resin coatings on performance of FeSiAl magnetic powder cores

引用

Journal of Iron and Steel Research International 2024年第5期31卷 1279-1288页

作者： jia-qi Liu zheng-qu Zhu Pu Wang yi-fan Li Jing Pang jia-quan Zhang School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing100083China Qingdao Yunlu Advanced Materials Technology Co. Ltd.Qingdao266232ShandongChina

Two silicon resins with excellent thermal stability,JH1123 and JH7102,are used as the insulated agents and binders for the gas-atomized FeSiAl powder,and corresponding magnetic powder cores(MPCs)are *** insulation capability and application prospects of the two silicon resins are evaluated by comparing the magnetic properties of the coated powder and *** scanning electron microscopy,energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy results show that uniform insulation layers are both formed on the powder ***1123 has stronger binding ability,and the JH1123-coated powder exhibits severe agglomeration,with d50(average particle size)approximately twice that of the JH7102-coated *** as-prepared MPCs exhibit outstanding soft magnetic ***,the permeability of FeSiAl@JH1123 is up to 74.0,which is 35.5%higher than that of FeSiAl@JH7102 because JH1123 can further improve the density of the *** for FeSiAl@JH7102,it has better direct current bias and lower core loss of 716.9 mW cm^(−3) at 20 mT and 1000 kHz due to its lower coercivity and greater anti-magnetic saturation ability.A comprehensive comparison shows that FeSiAl@JH1123 is suitable for medium and high frequency applications,while FeSiAl@JH7102 is more suitable for high frequency *** indicates that the use of JH1123 and JH7102 silicon resins for binding and insulated coating not only simplifies the preparation process of MPCs,but also enables the controlled production of MPCs for different applications.

关键词： FeSiAl Insulated coating Magnetic powder core Permeability Core loss

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Detection of astrophysical gravitational wave sources by TianQin and LISA

引用

Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 123-163页

作者： Alejandro Torres-Orjuela Shun-jia huang zheng-Cheng Liang Shuai Liu Hai-Tian Wang Chang-Qing Ye yi-Ming hu jianwei Mei MOE Key Laboratory of Tian Qin Mission Tian Qin Research Center for Gravitational PhysicsSchool of Physics and AstronomyFrontiers Science Center for Tian QinGravitational Wave Research Center of CNSASun Yat-Sen University(Zhuhai Campus)Zhuhai 519082China Department of Physics The University of Hong KongHong Kong 999077China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing100871China

TianQin and LISA are space-based laser interferometer gravitational wave(GW)detectors planned to be launched in the *** detectors will detect low-frequency GWs around 10^(-2)Hz;however,Tian Qin is more sensitive to frequencies above this common sweet-spot while LISA is more sensitive to frequencies below 10^(-2)***,Tian Qin and LISA will be able to detect the same sources but with different accuracy depending on the source and its *** consider some of the most important astrophysical sources—massive black hole binaries,stellar-mass black hole binaries,double white dwarfs,extreme mass ratio inspirals,light and heavy intermediate mass ratio inspirals,as well as the stochastic gravitational background of astrophysical origin—that Tian Qin and LISA will be able to *** each of these sources,we analyze how far they can be detected(detection distance)and how well their parameters can be measured(detection accuracy)using a Fisher Matrix *** compare the results obtained by the three detection scenarios(Tian Qin alone,LISA alone,and joint detection by LISA and Tian Qin)highlighting the gains from joint detection as well as the contribution of Tian Qin and LISA to a combined study of astrophysical *** particular,we consider the different orientations,lifetimes,and duty cycles of the two detectors to explore how they can give a more complete picture when working together.

关键词： wave extreme stochastic

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

YOLOv5ST:A Lightweight and Fast Scene Text Detector

引用

Computers, Materials & Continua 2024年第4期79卷 909-926页

作者： yiwei Liu yingnan Zhao yi Chen zheng hu Min Xia School of Computer and Science Nanjing University of Information Science and TechnologyNanjing210044China School of Automation Nanjing University of Information Science and TechnologyNanjing210044China

Scene text detection is an important task in computer *** this paper,we present YOLOv5 Scene Text(YOLOv5ST),an optimized architecture based on YOLOv5 v6.0 tailored for fast scene text *** primary goal is to enhance inference speed without sacrificing significant detection accuracy,thereby enabling robust performance on resource-constrained devices like drones,closed-circuit television cameras,and other embedded *** achieve this,we propose key modifications to the network architecture to lighten the original backbone and improve feature aggregation,including replacing standard convolution with depth-wise convolution,adopting the C2 sequence module in place of C3,employing Spatial Pyramid Pooling Global(SPPG)instead of Spatial Pyramid Pooling Fast(SPPF)and integrating Bi-directional Feature Pyramid Network(BiFPN)into the *** results demonstrate a remarkable 26%improvement in inference speed compared to the baseline,with only marginal reductions of 1.6%and 4.2%in mean average precision(mAP)at the intersection over union(IoU)thresholds of 0.5 and 0.5:0.95,*** work represents a significant advancement in scene text detection,striking a balance between speed and accuracy,making it well-suited for performance-constrained environments.

关键词： Scene text detection YOLOv5 lightweight object detection

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Effects of loneliness and isolation on cardiovascular diseases:a two sample Mendelian Randomization Study

引用

Journal of Geriatric Cardiology 2024年第3期21卷 340-348页

作者： jia-yin CAI Xin WANG Cong-yi zheng Xue CAO Zhen hu Run-Qing GU yi-Xin TIAN Ye TIAN Lan SHAO Lin-Feng ZHANG Zeng-Wu WANG Division of Prevention and Community Health National Center for Cardiovascular DiseaseNational Clinical Research Center of Cardiovascular DiseaseState Key Laboratory of Cardiovascular DiseaseFuwai HospitalPeking Union Medical College&Chinese Academy of Medical SciencesBeijingChina

BACKGROUND Loneliness and isolation are associated with multiple cardiovascular diseases(CVDs),but there is a lack of research on whether they were causally *** conducted a Mendelian Randomization(MR)study to explore causal relationships between loneliness and isolation and multiple *** Single nucleotide polymorphisms associated with loneliness and isolation were identified from a genome-wide association study(GWAS)of 455,364 individuals of European ancestry in the IEU GWAS *** data for 15 CVDs were also obtained from the IEU GWAS *** used three MR methods including inverse variance weighting,MR-Egger,and weighted median estimation to assess the causal effect of exposure on ***'s Q test and MR-Egger intercept test were used to evaluate the heterogeneity and *** MR analysis showed that loneliness and isolation were significantly associated with essential hypertension(OR=1.07,95%CI:1.03-1.12),atherosclerotic heart disease(OR=1.04;95%CI:1.02-1.06),myocardial infarction(OR=1.02;95%CI:1-1.04)and angina(OR=1.04;95%CI=1.02-1.06).No heterogeneity and pleiotropy effects were found in this *** Causal relationship of loneliness and isolation with CVDs were found in this study.

关键词： diseases cardiovascular angina

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Voluntary wheel running ameliorated the deleterious effects of high-fat diet on glucose metabolism,gut microbiota and microbial-associated metabolites

引用

Food Science and human Wellness 2024年第3期13卷 1672-1684页

作者： Ling Zhang Wenyu Zou Yongyan hu Honghua Wu ying Gao Junqing Zhang jia zheng Department of Endocrinology Peking University First HospitalBeijing 100034China Laboratory Animal Facility Peking University First HospitalBeijing 100034China

Exercise training is critical for the early prevention and treatment of obesity and diabetes ***,the mechanism with gut microbiota and fecal metabolites underlying the effects of voluntary wheel running on high-fat diet induced abnormal glucose metabolism has not been fully elaborated.C57BL/6 male mice were randomly assigned to 4 groups according to diets(fed with normal chow diet or high-fat diet)and running paradigm(housed in static cage or with voluntary running wheel).An integrative 16S rDNA sequencing and metabolites profiling was synchronously performed to characterize the effects of voluntary wheel running on gut microbiota and *** showed that voluntary wheel running prevented the detrimental effects of high-fat feeding on glucose metabolism 16S rDNA sequencing showed remarkable changes in Rikenella and Marvinbryantia *** profiling indicated multiple altered metabolites,which were enriched in secondary bile acid biosynthesis *** conclusion,our study indicated that voluntary wheel running significantly improved glucose metabolism and counteracted the deleterious effects of high-fat feeding on body weight and glucose *** further found that voluntary wheel running could integratively program gut microbiota composition and fecal metabolites changes,and may regulate muricholic acid metabolism and secondary bile acid biosynthesis in high-fat fed mice.

关键词： High-fat diet Voluntary wheel running Gut microbiota Metabolomics Glucose metabolism

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A multi-mechanism numerical simulation model for CO_(2)-EOR and storage in fractured shale oil reservoirs

引用

Petroleum Science 2024年第3期21卷 1814-1828页

作者： Yuan-zheng Wang Ren-yi Cao Zhi-Hao jia Bin-Yu Wang Ming Ma Lin-Song Cheng College of Petroleum Engineering China University of Petroleum(Beijing)Beijing102249China John&Willie Leone Department of Energy&Mineral Engineering The Pennsylvania State UniversityUniversity Park16802PA.USA

Under the policy background and advocacy of carbon capture,utilization,and storage(CCUS),CO_(2)-EOR has become a promising direction in the shale oil reservoir *** multi-scale pore structure distribution and fracture structure lead to complex multiphase flow,comprehensively considering multiple mechanisms is crucial for development and CO_(2) storage in fractured shale *** this paper,a multi-mechanism coupled model is developed by *** to the traditional Eclipse300 and MATLAB Reservoir Simulation Toolbox(MRST),this model considers the impact of pore structure on fluid phase behavior by the modified Peng—Robinson equation of state(PR-EOS),and the effect simultaneously radiate to Maxwell—Stefan(M—S)diffusion,stress sensitivity,the nano-confinement(NC)***,a modified embedded discrete fracture model(EDFM)is used to model the complex fractures,which optimizes connection types and half-transmissibility calculation approaches between non-neighboring connections(NNCs).The full implicit equation adopts the finite volume method(FVM)and Newton—Raphson iteration for discretization and *** model verification with the Eclipse300 and MRST is *** results show that the interaction between the mechanisms significantly affects the production performance and storage *** effect of molecular diffusion may be overestimated in oil-dominated(liquid-dominated)shale *** well spacing and injection gas rate are the most crucial factors affecting the production by sensitivity ***,the potential gas invasion risk is *** model provides a reliable theoretical basis for CO_(2)-EOR and sequestration in shale oil reservoirs.

关键词： CO_(2)-EOR CO_(2)storage Shale oil reservoir Complex fracture model Multiple mechanisms

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

6DOF pose estimation of a 3D rigid object based on edge-enhanced point pair features

引用

Computational Visual Media 2024年第1期10卷 61-77页

作者： Chenyi Liu Fei Chen Lu Deng Renjiao yi Lintao zheng Chenyang Zhu jia Wang Kai Xu College of Computing National University of Defense TechnologyChangsha410073China Department of Spine Surgery the Second Xiangya HospitalCentral South UniversityChangsha410011China Clinical Nursing Teaching and Research Section the Second Xiangya HospitalChangsha410011China College of Meteorology and Oceanography National University of Defense TechnologyChangsha410073China Beijing Institute of Tracking and Communication Technology Beijing100094China

The point pair feature(PPF)is widely used for 6D pose *** this paper,we propose an efficient 6D pose estimation method based on the PPF *** introduce a well-targeted down-sampling strategy that focuses on edge areas for efficient feature extraction for complex geometry.A pose hypothesis validation approach is proposed to resolve ambiguity due to symmetry by calculating the edge matching *** perform evaluations on two challenging datasets and one real-world collected dataset,demonstrating the superiority of our method for pose estimation for geometrically complex,occluded,symmetrical *** further validate our method by applying it to simulated punctures.

关键词： point pair feature(PPF) pose estimation object recognition 3D point cloud

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：