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Effect of light scattering on the performance of a direct absorption solar collector

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Frontiers in Energy 2018年第1期12卷 169-177页

作者： Kwang Hyun WON bong Jae lee Department of Mechanical Engineering Korea Advanced Institute ofScience and Technology Daejeon 34141 South Korea

Recently, a solar thermal collector often employs nanoparticle suspension to absorb the solar radiation directly by a working fluid as well as to enhance its thermal performance. The collector efficiency of a direct absorption solar collector （DASC） is very sensitive to optical properties of the working fluid, such as absorption and scattering coefficients. Most of the existing studies have neglected particle scattering by assuming that the size of nanoparticle suspension is much smaller than the wavelength of solar radiation （i.e., Rayleigh scattering is applicable）. If the nanoparticle suspension is made of metal, however, the scattering cross-section of metallic nanoparticles could be comparable to their absorption cross-section depending on the particle size, especially when the localized surface plasmon （LSP） is excited. Therefore, for the DASC utilizing a plasmonic nanofluid supporting the LSP, light scattering from metallic particle suspension must be taken into account in the thermal analysis. The present study investigates the scattering effect on the thermal performance of the DASC employing plasmonic nanofluid as a working fluid. In the analysis, the Monte Carlo method is employed to numerically solve the radiative transfer equation considering the volume scatter- ing inside the nanofluid. It is found that the light scattering can improve the collector performance if the scattering coefficient of nanofluid is carefully engineered depending on its value of the absorption coefficient.

关键词： direct absorption solar collector plasmonicnanofluid light scattering

Mechanisms involved in Korean mistletoe lectin-induced apoptosis of cancer cells

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World Journal of Gastroenterology 2007年第20期13卷 2811-2818页

作者： lee-Yong Khil Wi Kim Suyun Lyu Won bong Park Ji-Won Yoon hee-Sook Jun Department of Microbiology and Infectious Diseases Faculty of MedicineUniversity of CalgaryCalgaryAlbertaT2N 4N1Canada Immune Modulation Group Boots Science BuildingSchool of PharmacyUniversity of NottinghamUniversity ParkNottinghamNG7 2RDUnited Kingdom College of Natural Science Seoul Women’s UniversitySeoul 139-774Korea Department of Pathology Chicago Medical SchoolNorth ChicagoIL60064United States Sadly Department of Pathology Chicago Medical SchoolNorth ChicagoIL60064United States SadlyDr. Ji-Won Yoon passed away on April 62006

AIM： To investigate the anti-cancer mechanisms of Korean mistletoe lectin （Viscum album coloratura agglutinin, VCA） using a human colon cancer cell line （COLO）. METHODS： Cytotoxic effects of VCA on COLO cells were determined by 3-（4,5-dimethylthiazol-2-yl）-2,5- diphenyltetrazolium bromide （MTI-） assay in vitro and tumor-killing effects in vivo. To study the mechanisms involved, the expression of various pro-caspases, anti- apoptotic proteins, and death receptors was determined by western blot. To determine which death receptor is involved in VCA-induced apoptosis of COLO cells, cytotoxicity was examined by MTT assay after treatment with agonists or antagonists of death receptors. RESULTS： VCA killed COLO cells in a time- and dosedependent manner and induced complete regression of tumors in nude mice transplanted with COLO cells. Treatment of COLO cells with VCA activated caspase-2, -3, -8, and -9 and decreased expression of anti-apoptotic molecules including receptor interacting protein, nuclear factor-κB, X-linked inhibitor of apoptosis protein, and Akt/protein kinase B. We then examined the involvement of death receptors in VCA-induced apoptosis. Only tumor necrosis factor receptor 1, among the death receptors examined, was involved in apoptosis of COLO cells, evidenced by inhibition of VCA-induced apoptosis and decreased activation of caspases, particularly caspase-8, by tumor necrosis factor receptor 1 antagonizing ***： VCA-induced apoptotic COLO cell death is due to the activation of caspases and inhibition of antiapoptotic proteins, in part through the tumor necrosis factor receptor 1 signaling pathway.

关键词： Viscum album coloratum Lectin Apoptosis Tumor necrosis factor receptor-i Caspase Colon cancer

Friction and wear of textured surfaces produced by 3D printing

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Science China(Technological Sciences) 2017年第9期60卷 1400-1406页

作者： HONG Yi ZHANG Peng lee Kwang-hee lee Chul-hee Department of Mechanical Engineering Inha University Incheon 402-751 Korea

Surface texture patterns have great potential for improving tribological performance in terms of reducing friction and wear. The most common methods for surface texatring are laser and injection molding. The 3D printing method is also used to build parts, patterns, and molds that feature fine details for a wide range of applications because texture manufacturing by 3D printing is faster, more flexible, and less expensive than traditional techniques. To date, there has been no research on textured surfaces produced by 3D printing. Therefore, a new fabrication method using 3D printing to improve friction and wear properties is a topic worth exploring. In this study, a reciprocating friction tester was used to evaluate the friction and wear properties of different surface textures produced by 3D printing. The surface of specimens was examined by electron microscope and scanning electron microscope before and after the test. The results show that surface texturing can be applied to 3D printed parts to improve their friction and wear performance.

关键词： three-dimensional (3D) printing texture friction wear

Anti-inflammatory effects of traditional mixed extract of medicinal herbs(MEMH)on monosodium urate crystal-induced gouty arthritis

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Chinese Journal of Natural Medicines 2017年第8期15卷 561-575页

作者： Ju-Suk Nam Supriya Jagga Ashish Ranjan Sharma Joon-hee lee Jong bong Park Jun-Sub Jung Sang-Soo lee Institute For Skeletal Aging&Orthopedic Surgery Hallym University-Chuncheon Sacred Heart HospitalChuncheonGangwon-do24252Republic of Korea Institute of Natural Medicine College of MedicineHallym UniversityChucheonGangwon-do 24252Republic of Korea Hana Oriental Clinic ChucnheonGangwon-do 24433Republic of Korea

Korean oriental medicine prescription is widely used for the treatment of gouty diseases. In the present study, we investigated anti-inflammatory effects of modified Korean herbal formulation, mixed extract of medicinal herbs(MEMH), and its modulatory effects on inflammatory mediators associated with gouty arthritis. Both in vitro and in vivo studies were carried out to assess the anti-inflammatory efficacy of MEMH on monosodium urate(MSU) crystals-induced gouty inflammation. MSU crystals stimulated human chondrosarcoma cell line, SW1353, and human primary chondrocytes were treated with MEMH in vitro. The expression levels of pro-inflammatory mediators and metalloproteases were analyzed. The effect of MEMH on NFκB signaling pathway in SW1353 cells was examined. Effect of MEMH on the mR NA expression level of pro-inflammatory mediators and chemotactic factor from human monocytic cell line, THP-1, was also analyzed. The probable role of MEMH in the differentiation process of osteoblast like cells, SaO S-2, after MSU treatment was also observed. To investigate the effects of MEMH in vivo, MSU crystals-induced ankle arthritic model was established. Histopathological changes in affected joints and plasma levels of pro-inflammatory mediators(IL-1β and TNFα) were recorded. MEMH inhibited NFκB signaling pathway and COX-2 protein expression in chondrocytes. MSU-induced mR NA expressions of pro-inflammatory mediators and chemotactic cytokines were suppressed by MEMH. In MSU crystals-induced ankle arthritic mouse model, administration of MEMH relieved inflammatory symptoms and decreased the plasma levels of IL-1β and TNFα. The results indicated that MEMH can effectively inhibit the expression of inflammatory mediators in gouty arthritis, demonstrating its potential for treating gouty arthritis.

关键词： Gout Monosodium urate crystals Inflammation Chondrocyte Oriental medicine

Study on wear behavior of plasma electrolytic oxidation coatings on aluminum alloy

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Rare Metals 2006年第Z2期25卷 141-145页

作者： KANG Suk-bong lee Jung-Moo Department of Materials Engineering Korean Institute of Machinery & Materials Gyeongnam 641831 Korea

Thick and hard ceramic coatings were fabricated on A356 aluminum alloy by using plasma electrolytic oxidation(PEO) technique. The microstructure and phase composition of the PEO coatings were examined by using SEM and XRD method. It is found that the PEO coatings are mainly composed of crystalline α-Al2O3 and mullite. The dry sliding wear test of PEO coatings were carried out on a ring-on-ring wear machine. Results shows that there is hardly no wear loss of polished PEO coatings while the wear rate of uncoated aluminum alloy is 4.3×10-5 mm3·(N·m)-1 at a speed of 0.52 m·s-1 and a load of 40 N.

关键词： aluminum alloy plasma electrolytic oxidation ceramic coating wear

Research on Cavitation Characteristics and Influencing Factors of Herringbone Gear Pump

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Computer Modeling in Engineering & Sciences 2024年第6期139卷 2917-2946页

作者： Jinlong Yang Kwang-hee lee Chul-hee lee Department of Mechanical Engineering of Inha University Incheon22212South Korea

Cavitation is a common issue in pumps,causing a decrease in pump head,a fall in volumetric efficiency,and an intensification of outlet flow *** is one of the main hazards that affect the regular operation of the *** on pump cavitation mainly focuses on mixed flow pumps,jet pumps,external spur gear pumps,***,there are few cavitation studies on external herringbone gear *** addition,pumps with different working principles significantly differ in the flow and complexity of the internal flow ***,it is urgent to study the cavitation characteristics of external herringbone gear *** with experimentalmethods,visual research and cavitation area identification are achieved through computation fluid dynamic(CFD),and changing the boundary conditions and shape of the gear rotor is *** simulation yields a head error of only 0.003%under different grid numbers,and the deviation between experimental and simulation results is less than 5%.The study revealed that cavitation causes flow pulsation at the outlet,and the cavitation serious area is mainly distributed in the meshing gap and meshing *** can be inhibited by reducing the speed,increasing the inlet pressure,and changing the helix angle can be *** example,when the inlet pressure is 5 bar,the maximumgas volume fraction in themeshing area is less than 50%.These results provide a reference for optimizing the design and finding the optimal design parameters to reduce or eliminate cavitation.

关键词： Herringbone gear pump cavitation rotating speed inlet pressure helix angle TwinMesh

Discharge Characteristics of Large-Area High-Power RF Ion Source for Positive and Negative Neutral Beam Injectors

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Plasma Science and Technology 2016年第12期18卷 1220-1224页

作者： Doo-hee CHANG Seung Ho JEONG Min PARK Tae-Seong KIM bong-Ki JUNG Kwang Won lee Sang Ryul IN Division of Nuclear Fusion Engineering & Technology Development Korea Atomic Energy Research Institute

A large-area high-power radio-frequency（RF） driven ion source was developed for positive and negative neutral beam injectors at the Korea Atomic Energy Research Institute（KAERI）. The RF ion source consists of a driver region, including a helical antenna and a discharge chamber, and an expansion region. RF power can be transferred at up to 10 kW with a fixed frequency of 2 MHz through an optimized RF matching system. An actively water-cooled Faraday shield is located inside the driver region of the ion source for the stable and steady-state operations of high-power RF discharge. Plasma ignition of the ion source is initiated by the injection of argongas without a starter-filament heating, and the argon-gas is then slowly exchanged by the injection of hydrogen-gas to produce pure hydrogen plasmas. The uniformities of the plasma parameter,such as a plasma density and an electron temperature, are measured at the lowest area of the driver region using two RF-compensated electrostatic probes along the direction of the shortand long-dimensions of the driver region. The plasma parameters will be compared with those obtained at the lowest area of the expansion bucket to analyze the plasma expansion properties from the driver region to the expansion region.

关键词： neutral beam injector RF ion source plasma ignition power loading plasma parameters

Globus pharyngeus:A review of its etiology,diagnosis and treatment

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World Journal of Gastroenterology 2012年第20期18卷 2462-2471页

作者： bong Eun lee Gwang Ha Kim Department of Internal Medi cine Pusan National University School of Medicine and Biomedical Research InstitutePusan National University Hospital Busan 602-739South Korea

Globus is a persistent or intermittent non-painful sensation of a lump or foreign body in the *** is a commonly encountered clinical condition that is usually long-lasting,difficult to treat,and has a tendency to ***,due to the uncertain etiology of globus,it remains difficult to establish standard investigation and treatment strategies for affected patients. As a first step for managing globus,careful history taking and nasolaryngoscopy are *** the benign nature of the condition and the recent notion that gastroesophageal reflux disease is a major cause of globus,empirical therapy with a high dose of proton pump inhibitors is reasonable for patients with typical *** patients are nonresponsive to this therapy, definitive assessments such as endoscopy,multichannel intraluminal impedance/pH monitoring,and ma-nometry should be *** and language therapy,anti-depressants,and cognitive-behavioral therapy can be helpful in patients whose symptoms persist despite negative investigations.

关键词： Diagnosis Gastroesophageal reflux disease Globus Proton pump inhibitor Treatment

Combined exercise improves gastrointestinal motility in psychiatric in patients

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World Journal of Clinical Cases 2018年第8期6卷 207-213页

作者： bong Kil Song Yeon Soo Kim hee Soo Kim Jung-Woo Oh On lee Joon-Sik Kim Health and Exercise Science Laboratory Institute of Sports ScienceSeoul National University Namyangju Hanyang General Hospital

AIM To examine the effect of combined exercise on colonic transit time(CTT) in admitted psychiatric patients. METHODS Over a 6-mo period, consecutive in patients with mental illness were recruited from the Somang Hospital Psychiatry Unit. A combined exercise program that included 60 min per day of exercise 3 d per week for 12 wk was performed. Physical fitness and CTT of the patients were measured twice before and twice after the exercise program. CTT was measured using a multiple marker technique with a radio-opaque marker. Changes in the exercising patients' CTT and weight-,cardiovascular-and fitness-related parameters were statistically *** After the 12-wk combined exercise intervention, decreased intestinal transit time was observed in all CTTs of the exercise group, including the right CTT(exercise: 15.6 ± 15.2 vs 9.2 ± 11.9, control: 13.1 ± 10.4 vs 10.9 ± 18.7), left CTT(exercise: 19.7 ± 23.5 vs 10.4 ± 13.2, control: 19.2 ± 19.0 vs 16.9 ± 19.8), recto-sigmoid CTT(exercise: 14.3 ± 16.7 vs 6.7 ± 7.9, control: 15.0 ± 14.4 vs 19.3 ± 30.3), and total colonic transit time(TCTT)(exercise: 50.2 ± 38.1 vs 27.1 ± 28.0, control: 47.4 ± 34.6 vs 47.3 ± 47.3). After the 12-wk combined exercise period, TCTT was significantly shortened in the exercise group compared with that in the control group. In addition to eating habits, water intake, and fiber intake, the increased physical activity level as a result of the 12-wk combined exercise program reduced the CTT.

关键词： Combined exercise Constipation Colonic transit time Radio-opaque marker Psychiatry unit patient