• Journal of Hydrogen and New Energy
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• v.22 no.6
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• pp.780-786
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• 2011

Mg hydride had high hydrogen capacity (7.6%), lightweight and low cost materials and it was promising hydrogen storage material at high temperature. However, commercial applications of the Mg hydride are currently hindered by its high absorption/desorption temperature, and very slow reaction kinetics. one of the approaches to improve the kinetic is $MgH_x$ intermixed with carbon. And it shows that carbon and carbon allotropes have a beneficial effect on hydrogen sorption in Mg. The graphene is a kind of carbon allotropes which is easily desorbed reaction at low temperatures because its reaction is exothermic. In this work, the effect of graphene concentration on the kinetics of Mg hydrogen absorption reaction was investigated. The $MgH_x$-Graphene composites has been prepared by hydrogen induced mechanical alloy (HIMA). The synthesized powder was characterized by XRD and simultaneous TG, DSC analysis. The hydrogenation behaviors were evaluated by using a sievert's type automatic PCT apparatus. In this research, results of kinetic profiles exhibit hydrogen absorption rate of $MgH_x$-5wt.% and 10wt.% graphene composite, as 1.25wt.%/ms, 10.33wt.%/ms against 0.88wt.%/ms for $MgH_x$ alone at 473K.

• Journal of Hydrogen and New Energy
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• v.20 no.6
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• pp.512-518
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• 2009

Mg 및 Mg합금은 수소 저장량이 7.6wt.%로 비교적 높고 자원도 풍부하여 값이 싼 장점을 가지고 있으나 산화반응성이 높고 활성화 에너지가 크기 때문에 반응온도가 높고 반응시간이 긴 단점을 가지고 있다. 이러한 단점을 극복하기 위해 일반적으로 Mg 및 Mg합금의 표면 개질화, 금속간 화합물 형성, 전이금속 첨가에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 전이금속인 Nb를 촉매제로 사용하여 수소화 특성을 개선하고자 기계적 합금화법(MA;Mechanical Alloying)을 실시하여 복합재료를 합성한 후 수소화 반응을 평가하였다. XRD, SEM, TEM, PSA, TG/DSC 분석을 수행하였으며 Sievert's 형 PCT를 이용하여 온도 및 압력 변화에 따른 특성평가를 하였다. 전이금속인 Nb의 첨가로 수소화 반응개시온도가 낮아지고 수소 저장량이 향상되는 거동을 보였다. 특히, 5mass%Nb가 10mass%Nb 보다 수소 저장량 및 반응속도가 좋은 결과를 보였다.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.5
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• pp.9-16
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• 2004

The data link layer of the PCI Express must have the transmitting buffer that contains the packets to transmit next time. Also it must have the retry buffer that contains the packets which were already transmitted but have not been acknowledged by the corresponding target device. In the separated buffer architecture, the data link layer can not transmit the packets in the transmitting buffer if the reiry buffer space is not enough. In this paper, we propose an efficient buffer architecture which merges the transmitting buffer and the retry buffer to a single buffer. Since the proposed buffer can dynamically assign the size of the transmitting buffer and the retry buffer, it can improve the buffer usage efficiency and the data transfer efficiency. The simulation result shows that the proposed buffer has the higher data transfer efficiency than the separated buffer architecture about 39% when the total buffer size is 8K byte.

• Journal of Hydrogen and New Energy
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• v.21 no.2
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• pp.81-88
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• 2010

Hydrogen energy applications have recognized clean materials and high energy carrier. Accordingly, Hydrogen energy applies for fuel cell by Mg and Mg-based materials. Mg and Mg-based materials are lightweight and low cost materials with high hydrogen storage capacity. However, commercial applications of the Mg hydride are currently hinder by its high absorption/desorption temperature, and very slow reaction kinetics. Therefore one of the most methods to improve kinetics focused on addition transition metal oxide. Addition to transition metal oxide in $MgH_x$ powder produce $MgH_x$-metal oxide composition by mechanical alloy and it analyze XRD, EDS, TG/DSC, SEM, and PCT. This report considers kinetics by transition metal oxide rate and Hydrogen pressure. In this research, we can see behavior of hydriding/dehydriding profiles by addition catalyst (transition metal oxide). Results of PCI make a excellent showing $MgH_x$-5wt.% Sc2O3 at 623K, $MgH_x$-10wt.% $Sc_2O_3$ at 573K.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.676-681
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• 2002

Different types of transcripts encoding growth hormone (GH) were identified from cDNA libraries constructed with pituitaries of a marine fish species, greenling (Hexagrammos otakii). GH-homologous cDNA clones were isolated using the high-density filter hybridization and the expressed sequence tag techniques. Of 39 full-length positive cDNA clones, 31 clones ($79\%$) displayed an identical sequence, however, remaining 8 clones exhibited several polymorphisms in their sequences including (1) the length and sequence variability in the 5' upstream region, (2) insertional sequences in open reading frame, and (3) deletion and/or single nucleotide polymorphism in the untranslated 3' region. Based on RT-PCT and RNA dot blot analyses, these transcripts were proven to be expressed in a pituitary-specific manner.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1208-1214
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• 1997

This study was designed to know the effect of kimchi on the hematological and immunological parameters in vivo and in vitro, respectively. To study the effects of kimchi on the hematological parameters, rats(S.D., male) were divided into 4 groups and fed diets containing of 3%, 5% and 10% kimchi or kimchi free diet(control) for 6 weeks. The results of CBC(complete blood cell) tests obtained from the bloods of rates were as follows ; In 10% kimchi group, the level of WBC(white blood cells), RBC(red blood cells), Hgb(hemoglobin), Hct(hematocrit) were increased significantly than those of control group(p<0.05). MCV(mean corpuscular volume), one of the red cell indices, was also increased significantly in the animals fed 10% kimchi(p<0.05). RDW(Red cell distritution width) and PCT(plateletcrit) was lowest in 10% kimchi group(p<0.05). To examine the effects of kimchi on immune cell growth in vitro, three types of mouse immune cells-spleen cells, bone marrow cells, thymus cells-were cultured with extracts of salted Chinese cabbage, fresh kimchi and fermented kimchi(for 1 week) for 12 or 20 days. Control was supplemented with PBS(phosphate buffer saline) excluding kimchi extract. The results of spleen cell, bone marrow cell, and thymus cell cultures showed similar tendency: control medium accelerated death of cells, extracts of salted Chinese cabbage reduced the rate of cell death, and extracts of fresh kimchi and fermented kimchi promoted cell growth. From these results, it could be suggested that kimchi possibly has an effect on the hematopoietic ability and increases immune cell development and growth in vivo.

• Nuclear Engineering and Technology
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• v.37 no.4
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• pp.363-374
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• 2005

A heterogeneous thorium-based Kyung Hee Thorium Fuel (KTF) assembly design was assessed for application in the APR-1400 to study the feasibility of using thorium fuel in a conventional pressurized water reactor (PWR). Thermal hydraulic safety was examined for the thorium-based APR-1400 core, focusing on the Departure from Nucleate Boiling Ratio (DNBR) and Large Break Loss of Coolant Accident (LBLOCA) analysis. To satisfy the minimum DNBR (MDNBR) safety limit condition, MDNBR>1.3, a new grid design was adopted, that enabled grids in the seed and blanket assemblies to have different loss coefficients to the coolant flow. The fuel radius of the blanket was enlarged to increase the mass flow rate in the seed channel. Under transient conditions, the MDNBR values for the Beginning of Cycle (BOC), Middle of Cycle (MOC), and End of Cycle (EOC) were 1.367, 1.465, and 1.554, respectively, despite the high power tilt across the seed and blanket. Anticipated transient for the DNBR analysis were simulated at conditions of $112\%$ over-power, $95\%$ flow rate, and $2^{\circ}C$ higher inlet temperature. The maximum peak cladding temperature (PCT) was 1,173K for the severe accident condition of the LBLOCA, while the limit condition was 1,477K. The proliferation resistance potential of the thorium-based core was found to be much higher than that of the conventional $UO_2$ fuel core, $25\%$ larger in Bare Critical Mass (BCM), $60\%$ larger in Spontaneous Neutron Source (SNS), and $155\%$ larger in Thermal Generation (TG) rate; however, the radio-toxicity of the spent fuel was higher than that of $UO_2$ fuel, making it more environmentally unfriendly due to its high burnup rate.

• Journal of Dental Anesthesia and Pain Medicine
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• v.19 no.2
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• pp.91-99
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• 2019

Background: The imbalance between osteoblasts and osteoclasts can lead to pathological conditions such as osteoporosis. It has been reported that opioid adversely affect the skeletal system, but it is inconsistent. Remifentanil is currently used as an adjuvant analgesic drug in general anesthesia and sedation. The aim of the present study was to investigate the effect of remifentanil on the osteoblast differentiation and mechanism involved in this effect. Methods: The C2C12 cells (mouse pluripotent mesenchymal cell line) were used as preosteoblast. Osteoblastic differentiation potency was determined by alkaline phosphatase (ALP) staining. C2C12 cell migration by remifentanil was evaluated using Boyden chamber migration assay. The expression of Runx2 and osterix was evaluated by RT-PCT and western blot analysis to investigate the mechanism involved in remifentanil-mediated osteoblast differentiation. Results: ALP staining showed that remifentanil increased significantly osteoblast differentiation. In Boyden chamber migration assay, C2C12 cell migration was increased by remifentanil. RT-PCR and western blot analysis showed that the expression of Runx2 and osterix was upregulated by remifentanil. Conclusions: We demonstrated that remifentanil increased osteoblast differentiation in vitro by upregulation of Runx2 and osterix expression. Therefore, remifentanil has the potential for assisting with bone formation and bone healing.

• Journal of Hydrogen and New Energy
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• v.32 no.3
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• pp.156-162
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• 2021

Mg hydride has a relatively high hydrogen storage amount of 7.6wt%, and inexpensive due to abundant resources, but has high reaction temperature and long reaction time because of treble oxidation reactivity and upper activation energy. Their range of applications could be further extended if their hydrogenation kinetics and degradation behavior could be improved. Therefore, the effect of CaO has improved the hydrogenation kinetics and slowed down the degradation. This study focused on investigating whether to improve the hydrogenation kinetics by synthesizing Mg₂NiH_x-5wt% CaO composites. The Mg₂NiH_x-5wt% CaO composites have been synthesized by hydrogen induced mechanical alloying. The synthesized composites were characterized by performing X-ray diffraction, Scanning Electron Microscopy, Brunauer-Emmett-Teller, Thermogravimetric, and Sivert's type automatic pressure-composition-temperature analysis. Hydriding kinetics were performed using an automatic PCT measurement system and evaluated over the temperature range of 423 K, 523 K, and 623 K. As a result of calculating the hydrogen adsorption amount through the hydrogenation kinetics curve, it was calculated as about 0.42wt%, 0.91wt%, and 1.15wt%, the highest at 623 K and the lowest at 423 K.

• Journal of the Korean Society of Systems Engineering
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• v.16 no.2
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• pp.97-109
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• 2020

On March 11, 2011, an earthquake followed by a tsunami caused an extended station blackout (SBO) at the Fukushima Dai-ichi NPP Units. The accident was initiated by a total loss of both onsite and offsite electrical power resulting in the loss of the ultimate heat sink for several days, and a consequent core melt in some units where proper mitigation strategies could not be implemented in a timely fashion. To enhance the plant's coping capability, the Diverse and Flexible Strategies (FLEX) were proposed to append the Emergency Operation Procedures (EOPs) by relying on portable equipment as an additional line of defense. To assess the success window of FLEX strategies, all sources of uncertainties need to be considered, using a physics-based model or system code. This necessitates conducting a large number of simulations to reflect all potential variations in initial, boundary, and design conditions as well as thermophysical properties, empirical models, and scenario uncertainties. Alternatively, data-driven models may provide a fast tool to predict the success window of FLEX strategies given the underlying uncertainties. This paper explores the applicability of Artificial Intelligence (AI) to identify the success window of FLEX strategy for extended SBO. The developed model can be trained and validated using data produced by the lumped parameter thermal-hydraulic code, MARS-KS, as best estimate system code loosely coupled with Dakota for uncertainty quantification. A Systems Engineering (SE) approach is used to plan and manage the process of using AI to predict the success window of FLEX strategies under extended SBO conditions.