检索结果-南通市图书馆

Defence Technology（防务技术） 2024年第3期33卷 364-373页

作者： Guanghua Yi Xinhong Hao Xiaopeng Yan Jian dai Yangtian Liu Yanwen Han Science and Technology on Electromechanical Dynamic Control Laboratory School of Mechatronical EngineeringBeijing Institute of TechnologyBeijing 100081China BIT Tangshan Research Institute Beijing 100081China

Automatic modulation recognition(AMR)of radiation source signals is a research focus in the field of cognitive ***,the AMR of radiation source signals at low SNRs still faces a great ***,the AMR method of radiation source signals based on two-dimensional data matrix and improved residual neural network is proposed in this ***,the time series of the radiation source signals are reconstructed into two-dimensional data matrix,which greatly simplifies the signal preprocessing ***,the depthwise convolution and large-size convolutional kernels based residual neural network(DLRNet)is proposed to improve the feature extraction capability of the AMR ***,the model performs feature extraction and classification on the two-dimensional data matrix to obtain the recognition vector that represents the signal modulation *** analysis and simulation results show that the AMR method based on two-dimensional data matrix and improved residual network can significantly improve the accuracy of the AMR *** recognition accuracy of the proposed method maintains a high level greater than 90% even at -14 dB SNR.

关键词： Automatic modulation recognition Radiation source signals Two-dimensional data matrix Residual neural network Depthwise convolution

Testing and modelling of transient adhesion phenomena in rolling-sliding contacts

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

Friction 2024年第5期12卷 1016-1027页

作者： daniel KVARDA Alexander MEIERHOFER Klaus SIX Faculty of Mechanical Engineering Brno University of TechnologyBrno61669Czech Republic Virtual Vehicle Research GmbH Graz8010Austria

Transient adhesion effects in rolling–sliding contacts influence all aspects of train–track *** is of high importance specifically when these effects result in critically low adhesion,which poses a risk to traction and braking of railway *** study presents a model that can replicate the transient changes of the coefficient of adhesion with tested water and solid particle *** experimental data for the model are measured using a commercial ball-on-disc *** experimental results showed a liquid reservoir in front of the contact area that slowly reduces in *** observation was used in the modelling approach to divide the calculation into two stages where the reservoir is present and when it *** model was able to reproduce the occurrence of low adhesion region seen in experimental results with different particle concentrations.

关键词： coefficient of adhesion tribology transient effects wheel-rail contact

Comparison of the clinical effects of dual-modality endoscopy and traditional laparotomy for the treatment of intra-and extrahepatic bile duct stones

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastrointestinal Surgery 2024年第3期16卷 759-767页

作者： Wei Wang Hui Xia Bin dai Department of Hepatobiliary Surgery Wuhan No.1 HospitalWuhan 430030Hubei ProvinceChina

BACKGROUND Bile duct stones(BDSs)may cause patients to develop liver cirrhosis or even liver ***,the success rate of surgical treatment for intrahepatic and extrahepatic BDSs is not satisfactory,and there is a risk of postoperative *** To compare the clinical effects of dual-modality endoscopy(duodenoscopy and laparoscopy)with those of traditional laparotomy in the treatment of intra-and extrahepatic *** Ninety-five patients with intra-and extrahepatic BDSs who sought medical services at Wuhan No.1 Hospital between August 2019 and May 2023 were selected;45 patients in the control group were treated by traditional laparotomy,and 50 patients in the research group were treated by dual-modality *** following factors were collected for analysis:curative effects,safety(incision infection,biliary fistula,lung infection,hemobilia),surgical factors[surgery time,intraoperative blood loss(IBL)volume,gastrointestinal function recovery time,and length of hospital stay],serum inflammatory markers[tumor necrosis factor(TNF)-α,interleukin(IL)-6,and IL-8],and oxidative stress[glutathione peroxidase(GSH-Px),superoxide dismutase(SOD),malondialdehyde(MDA),and advanced protein oxidation products(AOPPs)].RESULTS The analysis revealed markedly better efficacy(an obviously higher total effective rate)in the research group than in the control *** addition,an evidently lower postoperative complication rate,shorter surgical duration,gastrointestinal function recovery time and hospital stay,and lower IBL volume were observed in the research ***,the posttreatment serum inflammatory marker(TNF-α,IL-6,and IL-8)levels were significantly lower in the research group than in the control *** with those in the control group,the posttreatment GSH-Px,SOD,MDA and AOPPs in the research group were equivalent to the pretreatment levels;for example,the GSH-Px and SOD levels were significantly higher,while the MDA and AOPP levels were

关键词： Dual-modality endoscopy Traditional laparotomy Intra-and extrahepatic bile duct stones Clinical efficacy

Consensus on glycemic management for patients with coronary heart disease and type 2 diabetes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Geriatric Cardiology 2024年第7期21卷 689-702页

作者： Li-Nong JI Yun-dai CHEN Cardiovascular Subcommittee of Chinese International Exchange and Promotion Association for Medical and Healthcare

The prevalence of patients with coronary heart disease(CHD)and diabetes mellitus is notably high,posing sig-nificant residual cardiovascular risks even after routine interventions such as antihypertensive,lipid-lowering,and antithrombot-ic *** studies have demonstrated that certain glucose-lowering medications confer cardiovascular benefits for pa-tients with type 2 ***,a survey indicates that cardiologists may not be fully acquainted with the optimal screen-ing timing,indicators,and diagnostic criteria for type 2 diabetes,and there is insufficient awareness and a low rate of prescrip-tion of novel glucose-lowering medications with proven cardiovascular efficacy,such as glucagon-like peptide-1 receptor agon-ists(GLP-1 RAs)and sodium-glucose co-transporter-2 inhibitors(SGLT-2i).In this context,based on domestic and international guidelines or consensus and the latest evidence-based evidence,this consensus aims to standardize the glycemic management for patients with acute coronary syndrome,chronic coronary syndrome,and perioperative management for percutaneous coronary *** highlights the key points of screening and diagnosis of type 2 diabetes,and the comprehensive management of cardiovascular risk in patients with *** consensus elaborates on the principles and algorithms of glycemic management for CHD patients,without involving acute complications of diabetes,clarifies the clinical practice of glucose-lowering medications with cardiovascular benefits,and promotes the standardized use of these medications in cardiovascular and other related spe-cialty ***,it addresses the glucose-lowering treatment to comprehensively reduce cardiovascular risks.

关键词： coronary patients routine

Dynamics of a predator-prey system with sublethal effects of pesticides on pests and natural enemies

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Biomathematics 2024年第1期17卷 151-175页

作者： Xiangjun dai Jianjun Jiao Qi Quan Airen Zhou School of Mathematical Sciences Guizhou Normal University Guiyang 550025P.R.China School of Mathematics and Statistics Guizhou University of Finance and Economics Guiyang 550025 P.R.China School of Date Science Tongren University Tongren 554300P.R.China

Considering the influence of sublethal concentration of pesticides on pests and natural enemies,we propose a pest-management model with impulsive effect on chemical control and biological control strategies periodic spraying pesticide and releasing predatory natural *** using the Floquet theory and the comparison theorem of impulsive differential equations,a sufficient condition for the global asymptotic stability of the pest-eradication periodic solution is *** persistence of the system is further studied,and a sufficient condition for the persistence of the system is ***,some numerical simulations are shown to verify our theoretical *** works indicate that the sublethal effects of insecticides and the release of predatory natural enemies play significant roles in pest control in agricultural production.

关键词： Predator-prey system sublethal effect global asymptotic stability permanence

Fecal microbiota transplantation for irritable bowel syndrome:Current evidence and perspectives

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2024年第16期30卷 2179-2183页

作者： Cong dai Yu-Hong Huang Min Jiang Department of Gastroenterology First Hospital of China Medical UniversityShenyang 110001Liaoning ProvinceChina

In this editorial we comment on the article published in the recent issue of the World journal of *** focus specifically on the mechanisms underlying the effects of fecal microbiota transplantation(FMT)for irritable bowel syndrome(IBS),the factors which affect the outcomes of FMT in IBS patients,and *** has emerged as a efficacious intervention for clostridium difficile infection and holds promise as a therapeutic modality for *** utilization of FMT in the treatment of IBS has undergone scrutiny in numerous randomized controlled trials,yielding divergent *** current frontier in this field seeks to elucidate these variations,underscore the existing knowledge gaps that necessitate exploration,and provide a guideline for successful FMT implementation in IBS *** the same time,the application of FMT as a treatment for IBS confronts several challenges.

关键词： Fecal microbiota transplantation Irritable bowel syndrome Microbiota Randomized controlled trial Meta-analysis

Optimized Design of Bio-Inspired Wind Turbine Blades

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Fluid Dynamics & Materials Processing 2024年第7期20卷 1647-1664页

作者： Yuanjun dai Dong Wang Xiongfei Liu Weimin Wu School of Mechanical Engineering Shanghai DianJi UniversityShanghai201306China School of Information Engineering Yinchuan University of Science and TechnologyYinchuan750000China School of Mechanical and Power Engineering Chongqing University of Science and TechnologyChongqing401331China School of Aeronautical Mechanical and Electrical Engineering Chongqing Aerospace PolytechnicChongqing400021China

To enhance the aerodynamic performance of wind turbine blades,this study proposes the adoption of a bionic airfoil inspired by the aerodynamic shape of an *** on the blade element theory,a non-uniform extraction method of blade elements is employed for the optimization design of the considered wind turbine ***,Computational Fluid Dynamics(CFD)is used to determine the aerodynamic performances of the eagle airfoil and a NACA2412 airfoil,thereby demonstrating the superior aerodynamic performance of the ***,a mathematical model for optimizing the design of wind turbine blades is introduced and a comparative analysis is conducted with respect to the aerodynamic performances of blades designed using a uniform extraction *** is found that the blades designed using non-uniform extraction exhibit better aerodynamic performance.

关键词： Airfoil wind turbines blade design CFD

Strong evidence for latitudinal diversity gradient in mosses across the world

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Plant Diversity 2024年第4期46卷 537-541页

作者： Hong Qian Zun dai Jian Wang Research and Collections Center Illinois State Museum1011 East Ash StreetSpringfieldIL 62703USA Bryology Laboratory School of Life SciencesEast China Normal UniversityShanghai 200241China Shanghai Institute of Eco-Chongming(SIEC) 3663 Northern Zhongshan RoadShanghai 200062China

Species richness generally decreases with increasing latitude,a biodiversity gradient that has long been considered as one of the few laws in *** latitudinal diversity gradient has been observed in many major groups of *** plants,the latitudinal diversity gradient has been observed in vascular plants,angiosperms,ferns,and ***,a conspicuous latitudinal diversity gradient in mosses at a global or continental scale has not been observed until ***,we analyze a comprehensive data set including moss species in each band of 20° in latitude *** results show that moss species richness decreases strongly with increasing latitude,regardless of whether the globe is considered as a whole or different longitudinal segments(e.g.,Old World versus New World) are considered *** result holds when variation in area size among latitudinal bands is taken into ***'s correlation coefficient between latitude and species richness is-0.99 for both the Northern and Southern *** bryophytes are an extant lineage of early land plants and because mosses not only include most of extant species of bryophytes but also are important constituents of most terrestrial ecosystems,understanding geographic patterns of mosses is particularly important The finding of our study fills a critical knowledge gap.

关键词： Bryophyte Latitudinal diversity gradient Moss Species density Species diversity

Arc Grounding Fault Identification Using Integrated Characteristics in the Power Grid

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

Energy Engineering 2024年第7期121卷 1883-1901页

作者： Penghui Liu Yaning Zhang Yuxing dai Yanzhou Sun School of Electrical Engineering and Automation Henan Polytechnic UniversityJiaozuo454003China Research and Development Center Guangdong Zhicheng Champion Group Co.Ltd.Dongguan523000China Henan Key Laboratory of Intelligent Detection and Control of Coal Mine Equipment Henan Polytechnic UniversityJiaozuo454003China

Arc grounding faults occur frequently in the power grid with small resistance grounding neutral *** existing arc fault identification technology only uses the fault line signal characteristics to set the identification index,which leads to detection failure when the arc zero-off characteristic is *** solve this problem,this paper presents an arc fault identification method by utilizing integrated signal characteristics of both the fault line and sound ***,the waveform characteristics of the fault line and sound lines under an arc grounding fault are *** that,the convex hull,gradient product,and correlation coefficient index are used as the basic characteristic parameters to establish fault identification ***,the logistic regression algorithm is employed to deal with the reference samples,establish the machine discrimination model,and realize the discrimination of fault ***,simulation test results and experimental results verify the accuracy of the proposed *** comparison analysis shows that the proposed method has higher recognition accuracy,especially when the arc dissipation power is smaller than 2×10^(3) W,the zero-off period is not *** conclusion,the proposed method expands the arc fault identification theory.

关键词： Arc fault convex hull algorithm correlation coefficient fault identification gradient logistic regression

Defect detection and repair algorithm for structures generated by topology optimization based on 3D hierarchical fully convolutional network

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Biomimetic Intelligence & Robotics 2024年第2期4卷 24-31页

作者： Zhiyu Wan Hai Lan Sichao Lin Houde dai School of Advanced Manufacturing Fuzhou UniversityJinjiang 362251China Quanzhou Institute of Equipment Manufacturing Haixi InstitutesChinese Academy of SciencesJinjiang 362216China Fujian Key Laboratory of Special Intelligent Equipment Safety Measurement and Control Fujian Special Equipment Inspection and Research InstituteFuzhou 350008China

Customized 3D-printed structural parts are widely used in surgical *** satisfy the mechanical properties and kinematic functions of these structural parts,a topology optimization technique is adopted to obtain the optimal structural layout while meeting the constraints and ***,topology optimization currently faces some practical challenges that must be addressed,such as ensuring that structures do not have significant defects when converted to additive manufacturing *** address this problem,we designed a 3D hierarchical fully convolutional network(FCN)to predict the precise position of the defective *** on the prediction results,an effective repair strategy is adopted to repair the defective structure.A series of experiments is conducted to demonstrate the effectiveness of our *** to the 2D fully convolutional network and the rule-based detection method,our approach can accurately capture most defect structures and achieve 89.88%precision and 95.59%***,we investigate the impact of different ways to increase the receptive field of our model,as well as the trade-off between different defect-repairing *** results of the experiment demonstrate that the hierarchical structure,which increases the receptive field,can substantially improve the defect detection *** the best of our knowledge,this paper is the first to investigate 3D defect prediction and repair for topology optimization in conjunction with deep learning algorithms,providing practical tools and new perspectives for the subsequent development of topology optimization techniques.

关键词： Topology optimization Additive manufacturing Deep learning 3D semantic segmentation Defect detection