• Title, Summary, Keyword: SMC

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A Study on Preparation of Fast Cure and Low Density SMC (속경화·저비중 SMC 제조에 관한 연구)

  • Kim, Eun Kyoung;Lee, Youngchul;Hwang, Seok-Ho
    • Applied Chemistry for Engineering
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    • v.7 no.3
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    • pp.511-517
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    • 1996
  • In this research, we studied curing and filler systems for preparation of fast cure SMC and low-density SMC, respectivly. Two curing systems were evaluated for fast cure SMC formulation. One is a mixed initiator system and the other is an activator system. For low-density SMC, glass micro-baloon(GMB) was used as a filler. Various SMC formulations were cured in an appropriate way, and their curing behavior and physical/mechanical properties were characterized. Curing rates were increased with increasing quantity of mixed initiator and activator, but mechanical properties were not affected. As the quantities of GMB increased, density and mechanical properties were decreased.

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The Role of Receptor Activator of NF-κ Ligand in Smooth Muscle Cell Proliferation (Smooth muscle cell 증식에 있어 NF-κ ligand의 receptor activator의 역할)

  • Kim, Hyun-Ju
    • Journal of Life Science
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    • v.16 no.6
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    • pp.1066-1070
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    • 2006
  • Smooth muscle cell (SMC) proliferation is important in the pathogenesis of vascular proliferative disorders. Understanding of the molecular mechanism underlying SMC growth after arterial injury would have therapeutic implications. Here we report that receptor activator of $NF-{\kappa}B$ ligand (RANKL), a member of tumor necrosis factor (TNF) family, promotes the proliferation of SMC, leading to decreased expression of p21 and enhancement of SMC growth. ERK and p38 phosphorylation was enhanced after RANKL treatment in SMC. Inhibition of ERK/p38 MAPK activity by PD98059/SB203580 completely abolished RANKL-induced proliferation of SMC, indicating ERK and p38 MAPK are essential for RANKL-induced SMC proliferation. Taken together, our findings demonstrate that RANK-RANKL-ERK/p38 pathway is important for proliferation of SMC and that these molecules may be the new therapeutic targets for the prevention of vascular diseases.

Design of a SMC-type FLC and Its Equivalence

  • 최병재;곽성우;김병국
    • Journal of the Korean Institute of Intelligent Systems
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    • v.7 no.5
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    • pp.14-20
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    • 1997
  • This paper proposes a new design method for the SMC-type FLC and shows that a SMC-type LFC is an extension of the SMC with BL. The conventional SMC-type FLC uses error and change-of-error as inputs of the FLC and generates the absolute value of a switching magnitude. Then, the fuzzy rule table is constructed on a two-dimensional space of the phase plane and has commonly the skew symmetric property. In this paper, we introduce a new variable, signed distance, from the skew symmetric property of the rule table. And thd variable becomes only a fuzzy variable that is used to generate the control input of a SMC-type FLC. that is, we design a new SMC-type FLC that uses a signed distance and a control input as the variables representing the contents of the rule-antecedent and the rule-con-sequent, respectively. Then the number of total rules is reduced and the control performance is almost the same as that of the conventional SMC-type FLC. Additionally, we derive the control law of the ordinary SMC with BL from a new SMC-type FLC. Namely, we show that a FLC is an extension of the SMC with BL.

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Agricultural Utilization of Paper Mill Sludge Manure Compost -I. Effects on the Growth of Kidney Bean (Phaseolus vulgaris L.) (제지(製紙)스럿지 퇴비(堆肥)의 농업적(農業的) 이용연구 -I. 강남콩에 대(對)한 시용효과)

  • Chang, Ki-Woon;Kim, Sang-Deog;Choi, Woo-Young;Lee, Kyu-Seung
    • Korean Journal of Soil Science and Fertilizer
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    • v.25 no.2
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    • pp.149-154
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    • 1992
  • A study was carried out to know the effects of two kinds of paper mill sludge manure compost(SMC) on the growth and chemical components of kidney bean(Phaseolus vulgaris) : Control(SMC-0) contained chemical fertilizer only, sludge manure compost-1(SMC-1) contained 18% of swine manure and 8% of sawdust of the total weight of the manure in addition to the chemical fertilizer, and sludge manure compost-2(SMC-2) contained swine manure without sawdust a third of the total by weight on a fresh weight basis, 1) Kidney bean treated with SMC-1 and SMC-2 showed the increasing tendency of values meristem height, stem diameter, pod number per plot and total grain yield when compared to control(SMC-0) treatment 2) Though there was not a significant difference between SMC-1 and SMC-2 treatments on the growth, SMC-1 tended to increase the value of meristem height, stem diameter, pod number per plot and total grain yield of kidney bean, 3) The contents of aluminium, iron and zinc in kidney bean were higher than other elements, though there was no significant difference between the treatments, And those of chromium, lead and cadmium were negligible. 4) From the results obtained, it can be said that SMC application has more favorable effects on the growth of the plant than control(SMC-0). The effects of SMC-1 application on the growth of kidney bean was more favorable than those of SMC-2.

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RVEGA SMC for Precise Level Control of Coupled Tank System (이중 탱크 시스템의 정밀 수위 제어를 위한 RVEGA SMC에 관한 연구)

  • 김태우;이준탁
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.13 no.4
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    • pp.102-108
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    • 1999
  • The sliding rmde controller(SMC) is known as having the robust variable structures for the nonlinear control systems such as coupled tank system with the pararretric perturbations and with the rapid disturbances. But the adaptive tuning algorit1uns for their pararreters are not satisfactory. Therefore, in this paper, a Real Variable Elitist Genetic Algorithm based Sliding Mode Controller (RVEGA SMC) for the precise control of the coupled tank level was tried. The SMC's switching pararreters were optimized easily and rapidly by RVEGA The simulation results showed that the tank level could be satisfactorily controlled without any overshoot and any steady-state error by the proposed RVEGA SMC.GA SMC.

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Development of RVE Reconstruction Algorithm for SMC Multiscale Modeling (SMC 복합재료 멀티스케일 모델링을 위한 RVE 재구성 알고리즘 개발)

  • Lim, Hyoung Jun;Choi, Ho-Il;Yoon, Sang Jae;Lim, Sang Won;Choi, Chi Hoon;Yun, Gun Jin
    • Composites Research
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    • v.34 no.1
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    • pp.70-75
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    • 2021
  • This paper presents a novel algorithm to reconstruct meso-scale representative volume elements (RVE), referring to experimentally observed features of Sheet Molding Compound (SMC) composites. Predicting anisotropic mechanical properties of SMC composites is challenging in the multiscale virtual test using finite element (FE) models. To this end, an SMC RVE modeler consisting of a series of image processing techniques, the novel reconstruction algorithm, and a FE mesh generator for the SMC composites are developed. First, micro-CT image processing is conducted to estimate probabilistic distributions of two critical features, such as fiber chip orientation and distribution that are highly related to mechanical performance. Second, a reconstruction algorithm for 3D fiber chip packing is developed in consideration of the overlapping effect between fiber chips. Third, the macro-scale behavior of the SMC is predicted by the multiscale analysis.

An Experimental Study on Heat Transfer and Flow in Compression Molding of SMC (SMC 압축성형의 열 및 유동에 관한 실험적 연구)

  • 김기택;정진호;임용택
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.9
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    • pp.2386-2395
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    • 1994
  • An experimental study on heat transfer and flow in compression molding of clss-B and A SMC(Sheet Molding Compounds) in a flat plate and a cross-sectional T-shape was carried out. The temperature was measured with thermocouples at two locations in the 4 layered SMC charge and pressure was measured at the center of the top mold during compression molding. Three different mold speeds, 15, 45, 50 mm/min and two different mold temperature, $130^{\circ}C{\;}and{\;}150^{\circ}C$ were used for compression molding experiments. Experiments with different colored SMC layers were used to study flow patterns at various compression stages. In oder to predict the pressure and load in SMC compression molding, slab method was used. The predicted values of pressure and load from the slab analysis were compared well with the measured data.

A Study on Material Characterization and Mechanical Properties of SMC Compression Molding Parts (SMC 압축성형재의 기계적 물성 및 특성에 관한 연구)

  • 김기택;임용택
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.9
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    • pp.2396-2403
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    • 1994
  • An experimental study on material characterization and mechanical properties of SMC(Sheet Molding Compounds) compression method parts was carried out. Simple compression test using grease oil as a lubricant was carried out to characterize flow stress of SMC at elevated temperatures. Two different mold temperatures, $130^{\circ}C{\;}and{\;}150^{\circ}C$ and two different mold speeds, 15, 45 mm/min were used for preparing the specimen of SMC compression molded parts. Surface roughness, tensile, and 3-point bending tests were used to determine the effects of molding temperatures and speeds on mechanical properties of compression molded SMC parts. Orientation and distribution of glass fiber in the compression molded SMC parts were also investigated by photographing the burnt flat specimen and taking SEM(Scanning Electron Microscope) of cross-sectional T-specimen.

A Study on Material Characterization of SMC (SMC의 물성치 평가에 관한 연구)

  • 정진호;한영원;임용택
    • Transactions of Materials Processing
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    • v.4 no.3
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    • pp.245-256
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    • 1995
  • SMC(Sheet Molding Compound), a thermoset composite material which consists of unsaturated polyester resin, fiberglass strands, fillers, and various chemical additives for curing agent, has been widely used in fabrication of structural components. The mechanical properties of molded SMS parts are strongly dependent on material flow results during compression molding process, while such flow in molds is affected by material characteristics. For numerical simulation of SMC molding process, estimation of material property of SMC must be accomplished. In this study, flow resistance of SMC was estimated through a simple compression test using a lubricant with grease oil under the constant strain rate condition at various temperatures and the result was compared with other material data available in the literature. The accuracy of the experimentally determined flow resistance was tested by finite element analyses of compression molding of SMC. Simulation results were compared with experimental results under the plane strain condition.

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Effects of the Supplementation Period of Spent Composts of Selenium-Enriched Mushrooms on Plasma Glutathione Peroxidase Activity and Selenium Deposition in Finishing Hanwoo Steers (셀레늄강화 버섯폐배지의 급여기간이 비육후기 거세한우의 혈중 글루타치온 과산화효소 활성 및 조직내 셀레늄축적에 미치는 영향)

  • 이성훈;박범영;여준모;김완영
    • Journal of Animal Science and Technology
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    • v.48 no.6
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    • pp.897-906
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    • 2006
  • This study was conducted to determine effects of different supplementation periods (2, 3 and 4 months) of spent composts of Se-enriched mushrooms (Se-SMC) on plasma glutathione peroxidase (GSH-Px) activity and selenium deposition of finishing Hanwoo steers for the optimal supplementing period determination in order to produce Se-fortified Hanwoo beef. In the present study, 30 Hanwoo steers were allotted to treatments in six groups of five steers per pen. Treatments were separated into control and Se-SMC for each supplementation period. Dietary selenium contents were 0.1 and 0.9 ppm for control and Se-SMC treatments, respectively. At the end of each supplementation period, steers by periods were slaughtered to collect hind leg and liver samples for their selenium analyses. Blood samples were taken to analyze whole blood Se concentration and plasma GSH-Px activity at the last day of each supplementation period. Dry matter intakes were unaffected by Se-SMC and supplementation periods. In addition, average daily gain was not different between control and Se-SMC treatments and among supplementation periods. There was no difference for total body weight gain between control and Se-SMC treatments within each supplementation period. The supplementation of Se-SMC significantly (P<0.001) increased whole blood Se concentration, but whole blood selenium concentration was not affected by the supplementation period. Furthermore, plasma GSH-Px activity showed similar trend as shown in the pattern of whole blood Se concentration, but no difference by supplementation periods was observed. Selenium contents in hind legs significantly (P<0.05) increased with increasing supplementation periods, and also they were significantly (P<0.001) higher for Se-SMC supplementation groups in comparison to controls. However, there was no difference for selenium contents of hind legs between three and four months supplementation. Selenium contents in livers tended to slightly increase with increasing supplementation periods with no significant difference, but they were significantly (P<0.01) higher for Se-SMC supplementation groups compared with controls within the same period. The results indicated that the optimal Se-SMC supplementation period for the selenium deposition in Hanwoo steers might be around two or three months when we considered selenium contents in hind legs and livers.