检索结果-南通市图书馆

Injection molding of micro patterned PMMA plate

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2011年第A01期21卷 148-152页

作者： yeong-Eun YOO Tae-Hoon KIM Tae-Jin JE Doo-Sun CHOI chang-Wan KIM Sun-Kyung KIM Department of Nanomanufacturing Technology KIMM 171 Jang-dong Yusung-gu Daejeon 305-343 Korea Department of Product Design and Manufacturing Seoul National University of Technology

A plastic plate with surface micro features was injection molded to investigate the effect of pressure rise of melt on the replication of the micro structures. Prism pattern, which is used in many optical applications, was selected as a model pattern. The prism pattern is 50 μm in pitch and 108° in the vertical angle. The overall size of the plate was 335 minx213 mm and the thickness of the plate varied linearly from 2.6 mm to 0.7 ram. The prism pattern was firstly machined on the nickel plated core block using micro diamond tool and this machined pattern core was installed in a mold for injection molding of prism patterned plate. Polymethyl methacrylate （PMMA） was used as a molding material. The pressure and temperature of the melt in the cavity were measured at different positions in the cavity and the replication of the pattern was also measured at the same positions. The results show that the pressure or temperature profile through the process depends on the shape and the size of the plate. The replication is affected by the temperature and pressure profiles at the early stage of filling, which is right after the melt reaches the position to be measured.

关键词： micro prism pattern injection molding replication pressure profile temperature profile

Sensitivity evaluation of the flash flood warning system introduced to ungauged small mountainous basins in Korea

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2019年第5期16卷 971-993页

作者： YOO Chulsang lee Jinwook chang Kwonhee YANG Dongmin School of Civil Environmental and Architectural Engineering College of Engineering Korea University NOAA SNC Co. Ltd.

This study evaluates the uncertainty involved in the determination of the flash flood guidance(FFG) of the flash flood warning system(FFWS) for a small mountainous region(FFWS_MR)in Korea. The sensitivity is evaluated both at each step to determine the FFG and for all steps together. The results show that the relative difference of the FFG is about 50% of the current system, most of which involves the channel width. Especially, the use of some specific empirical equations to estimate the major parameters results in a considerable amount of the relative difference of the FFG. In addition, though only four basins were field-surveyed, it is found that the indirect estimation of the major parameters always introduces some amount of additional uncertainty. In conclusion, accurate estimation of the major parameters must be the most important procedure to derive an accurate FFG, among which the channel cross-section at the exit of the basin lies at the center.

关键词： Flash flood warning system Flash flood guidance Sensitivity analysis

Trends in colorectal cancer incidence according to an increase in the number of colonoscopy cases in Korea

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastrointestinal Oncology 2024年第1期16卷 51-60页

作者： Ga Hee Kim yeong Chan lee Tae Jun Kim Sung Noh Hong Dong Kyung chang Young-Ho Kim Dong-Hoon Yang chang Mo Moon Kyunga Kim Hyun Gun Kim Eun-Ran Kim Division of Gastroenterology Department of Internal MedicineAsan Medical CenterUniversity of Ulsan College of MedicineSeoul 05505South Korea Department of Digital Health Samsung Advanced Institute for Health Science and TechnologySungkyunkwan University School of MedicineSeoul 06351South Korea Division of Gastroenterology Department of Internal MedicineSamsung Medical CenterSungkyunkwan University School of MedicineSeoul 06351South Korea Division of Gastroenterology Department of Internal MedicineEwha Womans UniversitySeoul 07985South Korea Biomedical Statistics Center Samsung Medical CenterSeoul 06351South Korea Division of Gastroenterology Department of Internal MedicineSoonchunhyang University College of MedicineSeoul 04401South Korea

BACKGROUND The incidence of colorectal cancer(CRC)and preinvasive CRC(e.g.,early colon cancer and advanced adenoma)is gradually increasing in several *** To evaluate the trend in incidence of CRC and preinvasive CRC according to the increase in the number of colonoscopies performed in *** This retrospective cohort study enrolled Korean patients from 2002 to 2020 to evaluate the incidence of CRC and preinvasive CRC,and assess the numbers of diagnostic colonoscopies and colonoscopic ***-related complications by age group were also *** The incidence of CRC showed a rapid increase,then decreased after 2012 in the 50-75 year-age *** the study period,the rate of incidence of preinvasive CRC increased at a similar level in patients under 50 and 50-75 years of *** 2009,the increase has been rapid,showing a pattern similar to the increase in *** rate of colonoscopic polypectomy in patients aged under 50 was similar to the rate in patients over 75 years of age after *** rate of complications after colonoscopy and related deaths within 3 mo was high for those over 75 years of *** The diagnosis of preinvasive CRC increased with the increase in the number of colonoscopies *** the risk of colonoscopy-related hospitalization and death is high in the elderly,if early lesions at risk of developing CRC are diagnosed and treated under or at the age of 75,colonoscopy-related complications can be reduced for those aged 76 years or over.

关键词： Colorectal cancer Preinvasive colorectal cancer Colorectal polypectomy Colonoscopy

CO2/CH4 separation using inside coated thin film composite hollow fiber membranes prepared by interfacial polymerization

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

Chinese Journal of Chemical Engineering 2017年第3期25卷 278-287页

作者： Eun-Sung Jo Xinghai An Pravin G.Ingole Won-Kil Choi yeong-Sung Park Hyung-Keun lee Korea Institute of Energy Research(KIER) 71-2 Jang-dongYuseong-guDaejeon 205343Republic of Korea Department of Environmental Engineering Daejeon UniversityDaejeonRepublic of Korea Department of Advanced Energy and Technology University of Science and Technology(UST)217 Gajeong-roYuseong-guDaejeon 305-350Republic of Korea

Carbon dioxide(CO_2) is greenhouse gas which originates primarily as a main combustion product of biogas and landfill gas. To separate this gas, an inside coated thin film composite(TFC) hollow fiber membrane was developed by interfacial polymerization between 1,3–cyclohexanebis–methylamine(CHMA) and trimesoyl chloride(TMC). ATR-FTIR, SEM and AFM were used to characterize the active thin layer formed inside the PSf hollow fiber. The separation behavior of the CHMA-TMC/PSf membrane was scrutinized by studying various effects like feed gas pressure and temperature. Furthermore, the influence of CHMA concentration and TMC concentration on membrane morphology and performance were investigated. As a result, it was found that mutually the CHMA concentration and TMC concentration play key roles in determining membrane morphology and performance. Moreover, the CHMA-TMC/PSf composite membrane showed good CO_2/CH_4 separation performance. For CO_2/CH_4 mixture gas(30/70 by volume) test, the membrane(PD1 prepared by CHMA 1.0% and TMC 0.5%) showed a CO_2 permeance of 25 GPU and the best CO_2/CH_4 selectivity of 28 at stage cut of 0.1. The high CO_2/CH_4 separation performance of CHMA-TMC/PSf thin film composite membrane was mostly accredited to the thin film thickness and the properties of binary amino groups.

关键词： Thin-film composite hollow fiber membrane Interfacial polymerization CHMA/TMC CO2/CH4 separation

Comparison between oxide-reduced and water-atomized copper powders used in making sintered wicks of heat pipe

在线全文

学校读者我要写书评

暂无评论

China Particuology 2007年第3期5卷 220-224页

作者： Liu-Ho Chiu chang-Hui Wu Pee-Yew lee Department of Materials Engineering Tatung University Taipei 10451 Taiwan China Institute of Materials Engineering Taiwan Ocean University Keelung Taiwan China

Oxide-reduced copper powder can be produced efficiently at low cost. The volume shrinkage, porosity, maximum pore size, permeability and thermal conductivity of wicks sintered from two oxide-reduced （OR） powders were compared with one from water-atomized （WA） powder. The green specimens were sintered at temperatures from 800 to 1000 ℃ in a tube furnace under a reduction stream of 10% hydrogen and 90% argon. The results show that the property variations of OR - 100 and WA wicks due to porosity changes have a similar tendency and range. Nine hundred degree celsius is a recommended sintering temperature for producing ideal wicks for use in heat pipes. A smaller maximum pore size can be obtained by increasing the green density.2007 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V.

关键词： Sintered wick Copper powder Porous property Oxide-reduced powder

Synthesis of a Rod-rod Diblock Copolymer, Poly (3-hexylthiophene)-block-poly(furfuryl isocyanate), through the Anionic Polymerization with an Oxyanionic Macroinitiator

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2019年第9期37卷 866-874页

作者： chang-Geun Chae Joonkeun Min In-Gyu Bak Jae-Suk lee School of Materials Science and Engineering Gwangju Institute of Science and Technology (GIST)

A rod-rod diblock copolymer (diBCP), poly(3-hexylthiophene)-block-poly(furfuryl isocyanate)(P3HT-b-PFIC), was synthesized through the anionic polymerization with an oxyanionic macroinitiator of P3HT. The properties of the diBCP (molecular weight, dispersity, composition, thermal stability, UV-visible absorption, and thin film morphology) were determined by various analytical methods. P3HT-b-PFIC was blended with C60 in a toluene solution to prepare a thin film of binary electron donor/acceptor system. Such blending enabled partial conjugation of the two components by the Diels-Alder reaction between furan and C60 at 60℃ for 3 h;the mixture was then spin-cast as a thin film, and annealed at 250℃ for 24 h. Tapping-mode atomic force microscopy (AFM) revealed that P3HT and C60 domains had nanoscale interfaces without a large phase segregation. This result indicated that the microphase separation of C60-functionalized P3HT-b-PFIC preserved even at high temperature provided free C60 molecules with channels to diffuse on the sides of P3HT domain, thus preventing the macroscopic crystallization of free C60 through the interfacial stabilization.

关键词： Rod-rod diblock copolymer Poly(3-hexylthiophene)-block-poly(furfuryl isocyanate) C60 Diels-Alder reaction Nanoscale interfaces

Acupoint catgut embedding for simple obesity in animal studies:a systematic review and Meta-analysis

在线全文

学校读者我要写书评

暂无评论

Journal of Traditional Chinese Medicine 2023年第5期43卷 860-867页

作者： ZHAO HuiYan JUN Purumea lee Chaewon HAN chang-Hyun Korean Convergence Medical Science University of Science and Technology(UST)School of Korea Institute of Oriental MedicineDaejeon 34054Republic of Korea KM Science Research Division Korea Institute of Oriental MedicineDaejeon 34054Republic of Korea KM Data Division Korea Institute of Oriental MedicineDaejeon 34054Republic of Korea St.Johnsbury Academy Jeju 304Global edu-roDaejeong-eupSeogwipo-si 63644Republic of Kore

OBJECTIVE:To assess the efficacy of acupoint catgut embedding(ACE)for simple obesity in preclinical animal ***:We searched the following 14 electronic databases:PubM ed,Cochrane Library,EMBASE,Oriental Medicine Advanced Searching Integrated System,KoreaMed,Korean Studies Information Service System,Science-on,Research Information Sharing Service,Korea Citation Index,Korea Traditional Knowledge Portal,China Network Knowledge Infrastructure Database,Wanfang Database,Chinese Science and Technology Journal Database,and Chinese Biology Medicine Database,from inception to November 2021 without language *** assessment was performed according to the guidelines of Animal Research:Reporting of in vivo experiments;and Metaanalysis was performed using Reviewer Manager 5.4.1 ***:Twenty-four studies involving 813 animals were ***-analysis showed that ACE was beneficial for weight control[n=40,MD=-50.63,95%CI(-57.59,-43.67),Plee index[n=40,MD=-18.79,95%CI(-20.01,-17.57),P<0.00001,I 2=0%].However,when efficacy of ACE was compared with that of manual acupuncture,electroacupuncture,or oilistat therapy,statistical difference was not observed between the two ***:This systematic review suggests that ACE may be efficacious in treating ***,the analyses highlighted the necessity to perform welldesigned,higher-quality experiments.

关键词： obesity acupoint catgut embedding animal study Meta-analysis systematic review

Finger vein recognition using weighted local binary pattern code based on a support vector machine

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science C(Computers and Electronics) 2010年第7期11卷 514-524页

作者： Hyeon chang lee Byung Jun KANG Eui Chul lee Kang Ryoung PARK Division of Electronics and Electrical Engineering Dongguk University Electronics and Telecommunications Research Institute Division of Fusion and Convergence of Mathematical Sciences the National Institute for Mathematical Sciences

Finger vein recognition is a biometric technique which identifies individuals using their unique finger vein patterns. It is reported to have a high accuracy and rapid processing speed. In addition, it is impossible to steal a vein pattern located inside the finger. We propose a new identification method of finger vascular patterns using a weighted local binary pattern (LBP) and support vector machine (SVM). This research is novel in the following three ways. First, holistic codes are extracted through the LBP method without using a vein detection procedure. This reduces the processing time and the complexities in detecting finger vein patterns. Second, we classify the local areas from which the LBP codes are extracted into three categories based on the SVM classifier: local areas that include a large amount (LA), a medium amount (MA), and a small amount (SA) of vein patterns. Third, different weights are assigned to the extracted LBP code according to the local area type (LA, MA, and SA) from which the LBP codes were extracted. The optimal weights are determined empirically in terms of the accuracy of the finger vein recognition. Experimental results show that our equal error rate (EER) is significantly lower compared to that without the proposed method or using a conventional method.

关键词： Finger vein recognition Support vector machine (SVM) Weight Local binary pattern (LBP)

CNN Accelerator Using Proposed Diagonal Cyclic Array for Minimizing Memory Accesses

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2023年第8期76卷 1665-1687页

作者： Hyun-Wook Son Ali AAl-Hamid Yong-Seok Na Dong-yeong lee Hyung-Won Kim Department of Electronics College of Electrical and Computer EngineeringChungbuk National UniversityCheongju28644Korea Department of Electrical Engineering College of EngineeringAl-Azhar UniversityCairo11651Egypt

This paper presents the architecture of a Convolution Neural Network(CNN)accelerator based on a newprocessing element(PE)array called a diagonal cyclic array(DCA).As demonstrated,it can significantly reduce the burden of repeated memory accesses for feature data and weight parameters of the CNN models,which maximizes the data reuse rate and improve the computation ***,an integrated computation architecture has been implemented for the activation function,max-pooling,and activation function after convolution calculation,reducing the hardware *** evaluate the effectiveness of the proposed architecture,a CNN accelerator has been implemented for You Only Look Once version 2(YOLOv2)-Tiny consisting of 9 ***,the methodology to optimize the local buffer size with little sacrifice of inference speed is presented in this *** implemented the proposed CNN accelerator using a Xilinx Zynq ZCU102 Ultrascale+Field Programmable Gate Array(FPGA)and ISE Design *** FPGA implementation uses 34,336 Look Up Tables(LUTs),576 Digital Signal Processing(DSP)blocks,and an on-chip memory of only 58 KB,and it could achieve accuracies of 57.92% and 56.42% mean Average Precession@0.5 thresholds for intersection over union(mAP@0.5)using quantized 16-bit and 8-bit full integer data manipulation with only 0.68% as a loss for 8-bit version and computation time of 137.9 and 69 ms for each input image respectively using a clock speed of 200 *** speeds are expected to be doubled five times using a clock speed of 1GHz if implemented in a silicon System on Chip(SoC)using a sub-micron process.

关键词： CNN accelerator systolic array memory optimization YOLOv2-tiny mAP@0.5