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345 GHz Band-Pass Filter Using Ultra-Precision Machining Technology

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Journal of Electronic Science and Technology 2017年第3期15卷 267-270页

作者： yu-kun li Yong Zhang Cai-Jie Ai Fundamental Science on Extremely High Frequency (EHF) Laboratory University of Electronic Science and Technology of China Chengdu 611731

This paper presents a terahertz（THz）band-pass filter using ultra-precision machining technology based on Chebyshev filter *** iris inductive window coupled waveguide filter was designed by using 8 resonant cavities with a center frequency of 345 GHz and a 7% *** final design fulfills the desired specifications and presents the minimum insertion loss of 1.55 d B and the return loss of less than 15 d B at 345 *** stop-band rejection is50 d B off the center frequency about 30 GHz,which means it has a good performance of high stop-band *** with the recent development of THz filters,this filter possesses the characteristic of simple structure and is easy to machining.

关键词： Index Terms--Filter prototype simple structure,ultra-precision machining technology.

Binary relevance for multi-label learning： an overview

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Frontiers of Computer Science 2018年第2期12卷 191-202页

作者： Min-ling ZHANG yu-kun li Xu-Ying liU Xin GENG School of Computer Science and Engineering Southeast University Nanjing 210096 China Key Laboratory of Computer Network and Information Integration (Southeast University) Ministry of Education China Collaborative Innovation Center for Wireless Communications Technology Nanjing 211100 China

Multi-label learning deals with problems where each example is represented by a single instance while being associated with multiple class labels simultaneously. Binary relevance is arguably the most intuitive solution for learning from multi-label examples. It works by decomposing the multi-label learning task into a number of independent binary learning tasks （one per class label）. In view of its potential weakness in ignoring correlations between labels, many correlation-enabling extensions to binary relevance have been proposed in the past decade. In this paper, we aim to review the state of the art of binary relevance from three perspectives. First, basic settings for multi-label learning and binary relevance solutions are briefly summarized. Second, representative strategies to provide binary relevance with label correlation exploitation abilities are discussed. Third, some of our recent studies on binary relevance aimed at issues other than label correlation exploitation are introduced. As a conclusion, we provide suggestions on future research directions.

关键词： machine learning multi-label learning binary relevance label correlation class-imbalance relative labeling-importance

Effect of Trace Sc and Zr on the Mechanical Properties and Microstructure of A1 Alloy 2618

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Journal of Materials Science & Technology 2000年第4期16卷 416-420页

作者： kun yu, Songrui li and Wenxian li (Department of Materials Science and Engineering, Central South University of Technology, Changsha 410083, China) Department of Materials Science and Engineering Central South University of Technology Changsha 410083 China

An experimental 2618(Al-Cu-Mg-Fe-Ni) alloy added with trace Sc and Zr was prepared by ingot metallurgy (IM) method. The aging behavior of the alloy was studied by Vickers hardness measurement at 200℃ and 300℃. and the tensile properties of alloy specimens were measured at 20℃, 200℃, 250℃ and 300℃. The microstructure was observed by using optical microscope, SEM and TEM. It was found that the addition of Sc and Zr to 2618 alloy resulted in a primary Al_3(Sc,Zr) phase which could refine the grain because it acts as nuclei of heterogeneous crystallization in the melt during solidification. The secondary Al_3(Sc,Zr) particles were full coherent with matrix and had obvious precipitation hardening effect. They also made the S' phase precipitate more homogeneous. So the strength of alloy increases at both ambient and elevated temperatures without a decrease of ductility. The ductile fracture of alloy occurs by microvoid nucleation, growth and coalescence, so the microvoid coalescence is the dominant fracture mechanism.

关键词： Sc Zr Effect of Trace Sc and Zr on the Mechanical Properties and Microstructure of A1 Alloy 2618

Semi-supervised remote sensing image scene classification with prototype-based consistency

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Chinese Journal of Aeronautics 2024年第2期37卷 459-470页

作者： Yang li Zhang li Zi WANG kun WANG Qifeng yu College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China

Deep learning significantly improves the accuracy of remote sensing image scene classification,benefiting from the large-scale ***,annotating the remote sensing images is time-consuming and even tough for *** neural networks trained using a few labeled samples usually generalize less to new unseen *** this paper,we propose a semi-supervised approach for remote sensing image scene classification based on the prototype-based consistency,by exploring massive unlabeled *** this end,we,first,propose a feature enhancement module to extract discriminative *** is achieved by focusing the model on the foreground ***,the prototype-based classifier is introduced to the framework,which is used to acquire consistent feature *** conduct a series of experiments on NWPU-RESISC45 and Aerial Image Dataset(AID).Our method improves the State-Of-The-Art(SOTA)method on NWPU-RESISC45 from 92.03%to 93.08%and on AID from 94.25%to 95.24%in terms of accuracy.

关键词： Semi-supervised learning Remote sensing Scene classification Prototype network Deep learning

Production,Properties and Microstructures of Mg-RE-Zn-Zr(RE=MM,Nd) Alloy

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Journal of Materials Science & Technology 2002年第4期18卷 378-380页

作者： kun yu, Wenxian li and Songrui liCollege of Materials Science and Engineering, Central South University, Changsha 410083, China Coll. of Mat. Sci. and Eng. Central South Univ. Changsha 410083 China

The Mg-MM and Mg-Nd master alloys were prepared through the ingot metallurgy method under the protection of a special flux. The thermodynamic behaviors of different rare earth elements in the molten Mg alloys were investigated. Two experimental alloys, Mg-3.0 wt pct MM-0.7 wt pct Zn-0.7 wt pct Zr and Mg-2.8 wt pct Nd-0.7 wt pct Zn-0.7 wt pct Zr, were prepared. The hardness and tensile properties of experimental alloys were measured and the microstructures were observed. The results showed that the rare earth elements could react greatly with the Mg chloride in the flux. The Mg-Nd-Zn-Zr alloy displayed a good aging hardening effect. The dispersed metastable phase ? (Mg3Nd) is an important strengthening phase to improve the tensile properties of this alloy. So the Mg-Nd-Zn-Zr alloy has better tensile properties and elongation than those of the Mg-MM-Zn-Zr alloy, and the ductile fracture character could be observed. The microvoid coalescence is the dominant fracture mechanism in this alloy.

关键词： Mg-RE-Zn-Zr alloy Rare earth Microstructures and properties

Effects of different doses of metformin on bone mineral density and bone metabolism in elderly male patients with type 2 diabetes mellitus

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World Journal of Clinical Cases 2020年第18期8卷 4010-4016页

作者： lin-Xia Wang Guang-Ya Wang Na Su Jie Ma yu-kun li Department of Endocrinology The Third Hospital of Hebei Medical UniversityShijiazhuang 050051Hebei ProvinceChina Second Department of Endocrinology Cangzhou Central HospitalCangzhou 061001Hebei ProvinceChina Key Orthopaedic Biomechanics Laboratory of Hebei Province Shijiazhuang 050051Hebei ProvinceChina

BACKGROUND Diabetes is a chronic disease,which may cause various *** with diabetes are at high risk of bone and joint disorders,such as osteoporosis and bone *** addition,it became widely accepted that diabetes has an important impact on bone *** is a commonly used and effective first-line treatment for type 2 *** glucose-lowering agents have been found to have an effect on bone *** present study explored if different doses of metformin have an effect on bone mineral density(BMD)and bone metabolism in type 2 *** To investigate the effects of different doses of metformin on BMD and bone metabolism in elderly male patients with type 2 diabetes *** A total of 120 elderly male outpatients with type 2 diabetes mellitus who were admitted to our hospital were included in the study from July 2018 to June *** were randomly assigned to an experimental group and a control group with 60 patients in each *** in the experimental group were given high dose metformin four times a day 0.5 g each time for 12 *** in the control group were given low dose metformin orally twice a day 0.5 g each time for 12 *** changes in bone mineral density and bone metabolism before and after treatment and the efficacy rate of the treatment were compared between the two *** There was no significant difference in the efficacy rate between the two groups(P>0.05).Before the treatment,there was no significant difference in BMD and bone metabolism between the two groups(P>0.05).However,after the treatment,BMD and bone metabolism were improved in the two ***,BMD and 25-hydroxyvitamin D were significantly higher in the experimental group than in the control group,and N-terminal/midregion andβ-isomerized Cterminal telopeptides were significantly lower in the experimental group than in the control group(all P<0.05).There was no significant difference in the incidence of adv

关键词： Dosages Metformin Type 2 diabetes mellitus Elderly male patients Bone mineral density Bone metabolism

Gasless endoscopic surgery through the upper chest in treatment of thyroid tumor

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Chinese Medical Journal 2011年第10期124卷 1449-1452页

作者： FANG Ju-gao FENG ling yu Zhen-kun li Ping-dong HAN De-min Department of Otolaryngology-Head & Neck Surgery Affiliated Beijing Tongren Hospital Capital Medical University Beijing 100730 China

Background Recently, there has been a surge of interest in minimally invasive techniques with endoscope in thyroid surgery. The aim of this study was to investigate the possibility of a scarless neck surgery under endoscopy for the treatment of thyroid tumor and to observe the results of this *** A total of 68 patients （64 women and 4 men） underwent the surgery. Their ages ranged from 18 to 65 years,with a mean age of （34±3） years. There were 64 cases of thyroid adenoma, and 4 cases of nodular goiter. An incision was made on the surface of the chest bone. The operation cavity was made by dragging the skin. Sixty-four patients underwent partial thyroid lobectomy, four patients underwent thyroid *** All 68 cases showed healing in one stage. None of the cases showed paralysis of the recurrent laryngeal nerve or tumor recurrence within the next 2 to 60 months of follow-up. The patients experienced slight pain after the *** patients were satisfied with the cosmetic results of the *** The gasless endoscopic surgery through the upper chest, which was performed to treat thyroid tumor, did not leave any scar, and was easy to handle, and gave good cosmetic results.

关键词： thyroid neoplasm gasless endoscopic surgery

Near real-time gravitational wave data analysis of the massive black hole binary with TianQin

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 175-186页

作者： Hong-yu Chen Xiang-yu Lyu En-kun li Yi-Ming Hu MOE Key Laboratory of TianQin Mission TianQin Research Center for Gravitational Physics&School of Physics and AstronomyFrontiers Science Center for TianQinGravitational Wave Research Center of CNSASun Yat-sen University(Zhuhai Campus)Zhuhai 519082China

Space-borne gravitational wave(GW)detectors can detect the merger of massive black *** early warning and localization of GW events before merging can be used to inform electromagnetic telescopes and conduct multimessenger ***,this requires real-time data transmission and analysis *** geocentric orbit of the space-borne GW detector Tian Qin makes it possible to conduct real-time data *** this study,we develop a search and localization pipeline for massive black hole binaries(MBHBs)with Tian Qin under both regular and real-time data transmission *** demonstrate that,with real-time data transmission,MBHBs can be accurately localized on the *** the approaching merger,each analysis can be finished in only 40 *** an MBHB system at a distance of 1 Gpc,if we receive data every hour,then we can pinpoint its location to within less than 1 deg^(2)on the final day before the merger.

关键词： gravitational wave detectors and experiments black holes data analysis algorithms and implementation data management

Mucinous adenocarcinoma:A unique clinicopathological subtype in colorectal cancer

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World Journal of Gastrointestinal Surgery 2021年第12期13卷 1567-1583页

作者： An Huang Yong Yang Jing-Yi Shi yu-kun li Jing-Xuan Xu yu Cheng Jin Gu Key Laboratory of Carcinogenesis and Translational Research(Ministry of Education/Beijing) Department of Gastrointestinal Surgery IIIPeking University Cancer Hospital&InstituteBeijing 100142China Peking-Tsinghua Center for life Science Peking University International Cancer CenterBeijing 100142China Department of Gastrointestinal Surgery Peking University Shougang HospitalBeijing 100144China

Mucinous adenocarcinoma(MAC)is a unique clinicopathological subtype of colorectal cancer,which is characterized by extracellular mucinous components that comprise at least 50%of the tumor *** clinical characteristics,molecular features,response to chemo-/radiotherapy,and prognosis of MAC are different from that of non-MAC(NMAC).MAC is more common in the proximal colon,with larger volume,higher T-stage,a higher proportion of positive lymph nodes,poorer tumor differentiation,and a higher proportion of peritoneal implants compared to *** biopsy is the main diagnostic method for MAC,magnetic resonance imaging is superior in accuracy,especially for rectal *** aberrant expression of mucins,including MUC1,MUC2 and MUC5AC,is a notable feature of MAC,which may be related to tumor invasion,metastasis,inhibition of apoptosis,and chemo-/radiotherapy *** genetic origin of MAC is mainly related to BRAF mutation,microsatellite instability,and the CpG island methylator phenotype *** addition,the poor prognosis of rectal MAC has been confirmed by various studies,and that of colonic MAC is still *** this review,we summarize the epidemiology,clinicopathological characteristics,molecular features,methods of diagnosis,and treatments of MAC in order to provide references for further fundamental and clinical research.

关键词： Mucinous adenocarcinoma Colorectal cancer Mucin Microsatellite instability Magnetic resonance imaging Treatment