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Assessment of nutrient distributions in Lake Champlain using satellite remote sensing

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Journal of Environmental Sciences 2014年第9期26卷 1831-1836页

作者： Elizabeth M.Isenstein Mi-hyun park Department of Civil and Environmental Engineering University of Massachusetts AmherstMA01003USA

The introduction of nutrients to lakes causing eutrophic conditions is a major problem around the world. Proper monitoring and modeling are important to effectively manage eutrophication in lake waters. The goal is to develop remote sensing models for nutrients, total phosphorus and total nitrogen, in Lake Champlain. The remote sensing models were created using multivariate linear regression with the unique band combinations of Landsat Enhanced Thematic Mapper Plus （ETM＋） imagery based on the empirical relationship with the field observations. The resulting models successfully showed nutrient distributions in the most eutrophic part of Lake Champlain, Missisquoi Bay, with reasonable adjusted coefficient of determination values （R2 = 0.81 and 0.75 for total phosphorus and total nitrogen, respectively）. The results show the feasibility and the utility of satellite imagery to detect spatial distributions of lake water quality constituents, which can be used to better understand nutrient distributions in Lake Champlain. This approach can be applicable to other lakes experiencing eutrophication assisting decision making when implementing Best Management Practices and other mitigation techniques to lakes.

关键词： Remote sensingMonitoringNutrientsPhosphorus

Investigation on static routing and resource assignment of elastic all-optical switched intra-datacenter networks

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Science China(Information Sciences) 2016年第10期59卷 60-75页

作者： Limei PENG Kiejin park Chan-hyun YOUN Department of Industrial Engineering Ajou University Department of Integrative Systems Engineering Ajou University Department of Electrical Engineering Korea Advanced Institute of Science and Technology

In this paper, we explore the issue of static routing and spectrum/IT resource assignment(RSIA)of elastic all-optical switched intra-datacenter networks(intra-DCNs) by proposing anycast- and manycastbased integer linear programming(ILP) models. The objective is to jointly optimize the DCN resources, i.e.,network transmission bandwidth and IT resources, under different situations. First, for given service-request matrices with unknown network transmission bandwidth and IT resources, we propose anycast and manycast ILP models to minimize the maximum numbers of required network and IT resources to accommodate all the service requests. For anycast RSIA issue, we proposed two different ILP models that are based on node-arc and link-path methods, respectively. Node-arc based manycast ILP model is also proposed for the first time to our knowledge. Second, for given network transmission bandwidth and IT resources and known servicerequest matrices, we propose node-arc based anycast ILP models to maximize the total number of successfully served service requests. To evaluate the efficiency of anycast and manycast models, all proposed ILP models are evaluated and compared with unicast ILP models. Simulation results show that anycast and manycast ILP models perform much better in efficiently using DCN resources and successfully accommodating more service requests when compared to unicast ILP models under the same network conditions.

关键词： datacenter networks(DCNs) intra-DCN RSIA ILP models anycast manycast

Effects of Korean Red Ginseng on Semen Parameters in Male Infertility Patients:A Randomized,Placebo-Controlled,Double-Blind Clinical Study

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Chinese Journal of Integrative Medicine 2016年第7期22卷 490-495页

作者： hyun Jun park Sangmin Choe Nam Cheol park Department of Urology Pusan National University School of MedicineBusan(602-739)Republic of Korea Medical Research Institute of Pusan National University Hospital Busan(602-739)Republic of Korea Division of Clinical Pharmacology Clinical Trial CenterPusan National University HospitalBusan(602-739)Republic of Korea

Objective： To investigate the effects of Korean red ginseng （KRG） on semen parameters in male infertility patients in a randomized, double-blind, placebo-controlled study. Methods： A total of 80 male infertility patients with varicocele were recruited from April 2011 to February 2012. The subjects were then divided into the following four groups： non-varicocelectomy （V）＋placebo （P） group, V＋P group, non-V＋KRG group （1.5-g KRG daily）, and V＋KGR group （1.5-g KRG daily）. Semen analysis was performed and hormonal levels were measured in each treatment arm after 12 weeks. Results： All groups but not the non-V＋P group, showed significant improvements in sperm concentrations, motility, morphology, and viability at the end of the study. However, there were no significant differences in serum follicle-stimulating hormone, luteinizing hormone, and testosterone among groups. The incidence of adverse events was low, and all events were assumed to be unrelated to the treatments administered. Conclusions： Although the exact mechanism by which KRG improves spermatogenesis remains unclear, KRG may be a useful agent for the treatment of male infertility. Nevertheless, additional studies to evaluate the optimal dose and duration of treatment are needed.

关键词： Panax ginseng male infertility spermatogenesis

Fatigue crack in large-scale tubular joints for offshore structures

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Science China(Technological Sciences) 2011年第3期54卷 705-714页

作者： chul-Hee JO Sung-Woo IM Won-chul CHO Kwan-Kyu park Department of Naval Architecture and Ocean Engineering Inha University Research Institute of Industrial Science and Technology Department of Civil & Environmental Engineering Chung-Ang University Samsung Heavy Industry Inc.

Tubular members have been used for constructing offshore structures. Large-scale fatigue tests of welded tubular K-joints under the balanced in-plane bending brace were carried out to investigate the fatigue behavior of API 2W Gr.50 steel produced by POSCO. The experimental results were verified by numerical approaches and compared with the IIW, DnV RP-C203 and API RP 2A-WSD design curves. The test results based on the hot spot stress were in agreement with the design curves. The SCF factor for tubular K-joint was also obtained. The numerical parametric study of the K-joint (using the finite element program) was described and its results were compared with experimental results. The stress effects of various parameters including α, β, γ, τ and θ on the stress in the K-joint were investigated. The stress distribution for each parameter was introduced. The study showed that the maximum stress of the joint varied according to the variation of joint parameters.

关键词： tubular K-joint API 2W Gr.50 hot spot stress SCF fatigue through-thickness crack S-N curve numerical parametric study

Tribological properties of hierarchical micro-dimples produced on a cylindrical surface by dual-frequency texturing

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Friction 2023年第2期11卷 246-258页

作者： Saood ALI Rendi KURNIAWAN park Gun chul Tae Jo KO School of Mechanical Engineering Yeungnam UniversityGyeongsan-si 712749Republic of Korea

An experimental investigation was performed for investigating the tribological performance of micro-dimple surface texture patterns on a cylindrical surface in a realistic operating environment of starved lubrication. Micro-dimples were generated by a dual-frequency surface texturing method, in which a high-frequency (16.3 kHz) three-dimensional (3D) vibration and a low-frequency (230 Hz) one-dimensional (1D) vibration were applied at the tool tip simultaneously, resulting in the generation of the hierarchical micro-dimples in a single step. Rotating cylinder-on-pin tribological tests were conducted to compare the tribological performance of the non-textured reference specimen and micro-dimple samples. The effect of surface textures generated with various shape parameters (long drop and short drop), dimension parameters (length and surface texture density), and operation parameters (load and sliding velocity) on the tribological performance was evaluated. Stribeck curves indicate that the hierarchical micro-dimples exhibit a lower coefficient of friction than the reference specimen in the high contact-pressure regions. It is also observed that variation in the length of a micro-dimple, the shape effect, is the major factor affecting the friction response of the textured surfaces. The generation of additional hydrodynamic pressure and lift effect by hierarchical structures is the main reason for the improved performance of hierarchical micro-dimple surfaces.

关键词： dual-frequency surface texturing hierarchical surfaces tribology starved lubrication three-dimensional elliptical vibration transducer

Enhanced photocatalytic degradation of lindane using metal–semiconductor Zn@ZnO and ZnO/Ag nanostructures

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Journal of Environmental Sciences 2018年第12期30卷 107-115页

作者： Hyeon Jin Jung Ravindranadh Koutavarapu Seulki Lee Ju hyun Kim hyun chul Choi Myong Yong Choi Department of Chemistry (BK21+) and Research Institute of Natural Science Gyeongsang National University Department of Chemistry Chonnam National University

To achieve enhanced photocatalytic activity for the degradation of lindane, we prepared metal–semiconductor composite nanoparticles（NPs）. Zn@ZnO core–shell（CS） nanocomposites, calcined ZnO, and Ag-doped ZnO（ZnO/Ag） nanostructures were prepared using pulsed laser ablation in liquid, calcination, and photodeposition methods, respectively, without using surfactants or catalysts. The as-prepared catalysts were characterized by using X-ray diffraction（XRD）, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, ultraviolet–visible（UV–vis） spectroscopy, and photoluminescence spectroscopy. In addition, elemental analysis was performed by energy dispersive X-ray spectroscopy. The obtained XRD and morphology results indicated good dispersion of Zn and Ag NPs on the surface of the ZnO nanostructures. Investigation of the photocatalytic degradation of lindane under UV–vis irradiation showed that Zn@ZnO CS nanocomposites exhibit higher photocatalytic activity than the other prepared samples. The maximum degradation rate of lindane was 99.5% in 40 min using Zn@ZnO CS nanocomposites. The radical trapping experiments verified that the hydroxyl radical（·OH） was the main reactive species for the degradation of lindane.

关键词： Zn@ZnO ZnO/Ag Lindane Pulsed laser ablation in liquid Photocatalysis

Cholecystoduodenal fistula presenting with upper gastrointestinal bleeding: A case report

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World Journal of Clinical Cases 2021年第2期9卷 410-415页

作者： Jin Myung park Chang Don Kang Ji hyun Kim Sang Hoon Lee Seung-Joo Nam Sung chul park Sung JoonLee Seungkoo Lee Department of Internal Medicine Kangwon National University School of MedicineChuncheon 24289Kangwon DoSouth Korea Department of Gastroenterology Kangwon National University HospitalChuncheon 24289Kangwon DoSouth Korea Anatomy and Pathology Kangwon National University School of MedicineChuncheon 200947Kangwon DoSouth Korea Department of Pathology Kangwon National University HospitalChuncheon 24289Kangwon DoSouth Korea

BACKGROUND Cholecystoduodenal fistula is a rare complication of *** are usually non-specific and often indistinguishable from those of etiologic diseases,but it rarely presents as severe gastrointestinal *** associated with cholecystoduodenal fistula usually requires surgery because significant bleeding from the cystic artery is unlikely to be resolved by conservative management or endoscopic *** SUMMARY We report a case of cholecystoduodenal fistula that presented with hematemesis which was diagnosed by endoscopy and computed *** hemostasis could not be achieved,but surgical treatment was ***,we have presented a literature *** Cholecystoduodenal fistula should be considered as differential diagnosis when a patient with history of gallstone disease presents with gastrointestinal bleeding.

关键词： Biliary fistula Hematemesis Cholecystitis Gallstones Cholecystectomy Case report

Copper telluride with manipulated carrier concentrations for high-performance solid-state thermoelectrics

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Journal of Materials Science & Technology 2022年第34期129卷 190-195页

作者： hyun Ju Dabin park Minsu Kim Jooheon Kim G.W.Woodruff School of Mechanical Engineering Georgia Institute of TechnologyAtlantaGA 30332USA School of Chemical Engineering&Materials Science Chung-Ang UniversitySeoul 06974Republic of Korea Department of Intelligent Energy and Industry Graduate SchoolChung-Ang UniversitySeoul 06974Republic of Korea Department of Advance Materials Engineering Chung-Ang UniversityAnseong 17546Republic of Korea

This study proposed a strategy for effectively diminishing the carrier concentration in Cu_(2)Te by introducing graphene sheets,Based on thermoelectric property measurements and single parabolic band modeling,the incorporated graphene effectively reduced the carrier concentration,not only enhancing the thermoelectric performance of the Cu_(2)Te/graphene composite but also substantially improving its figure of merit up to ~1.47 at 1000 K,which is 268% higher than that of pristine Cu_(2)Te,This study gives an insight into the control of carrier concentration and thermoelectric properties in Cu_(2)Te,and it could be extended to other copper chalcogenides for excellent thermoelectrics.

关键词： Thermoelectric Copper telluride Graphene Carrier concentration Single parabolic band model

Intraoperative optical coherence tomography findings during surgery for optic disc pit-associated maculopathy

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International Journal of Ophthalmology(English edition) 2020年第4期13卷 684-686页

作者： hyun Goo Kang Sung Eun park Eun Young Choi Sung chul Lee Min Kim Department of Ophthalmology Institute of Vision ResearchGangnam Severance HospitalYonsei University College of Medicine211 EonjuroGangnam-guSeoul 06273Republic of Korea Department of Ophthalmology Institute of Vision ResearchSeverance HospitalYonsei University College of Medicine134 Shinchon-dongSeodaemun-guSeoul 06273Republic of Korea

Dear Editor,We report our experience using a continuous intraoperative optical coherence tomography(OCT)-enabled microscope system for real-time anatomical evaluation of the optic pit during surgery in an 8-year-old girl who presented with symptomatic optic disc pit(ODP) maculopathy. ODP is an extremely rare congenital anomaly secondary to colobomatous malformation of the optic nerve head, with a reported incidence of 0.00009%[1]. Although patients are frequently asymptomatic, approximately 40%-50% of patients experience visual symptoms because of subretinal fluid(SRF) accumulation beneath the macula.

关键词： surgery maculopathy congenital