Development of a Fully Implicit Three-Field Solver for a Channel Flow with a Mixture Level Tracking Model

Moonkyu Hwang,Sung-Won Bae,Young-Jin Lee,Bub-Dong Chung 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6

In this study, a fully implicit solver is developed for a one-dimensional channel flow as three-fields. The current work treats separately the thermal energy for the continuous and entrained liquids, as opposed to a combined liquid treatment. Newton’s method is employed to establish the solution for the non-linear equation system iteratively. The Jacobian matrix for the Newton’s method is determined by a numerical differentiation, rather than an analytical evaluation. The process considerably simplifies the task, especially when complex interphase phenomena models have to be treated simultaneously. To mitigate the numerical diffusion problem of a highly diffusive upwind scheme, a mixture level tracking model is also developed, to selectively send or receive the relevant phase, for the mass and energy convections. Several conceptual tests, including a manometer U-tube oscillation test, were implemented to verify the soundness of the developed solver. The mixture level tracking model is found to be extremely effective in mitigating a numerical diffusion. The solver is expected to be a useful tool for developing and evaluating the multi-phase phenomena models in a channel flow.

철도경쟁도입에 따른 철도관련서비스(Rail Related Services) 개념정립에 관한 방안

최문규(MoonKyu Choi),송성태(SungTae Song) 한국철도학회 2013 한국철도학회 학술발표대회논문집 Vol.2013 No.5

철도경쟁도입과 관련된 여러가지 쟁점 중 신규철도운영자에게 제공되어야 할 시설 및 서비스라고 하는 철도관련서비스(Rail Related Services)의 개념을 유럽연합의 원칙에 의해 최소접근패키지와 추가적 및 보조적 서비스로 구분하고 이러한 서비스와 필수시설과의 관계를 검증하는 방안을 제시함으로써 경쟁도입 시 신규철도운영자에게 제공되어야 할 철도시설 및 서비스의 범위 및 제공비용 등에 대한 기준을 정립하고 경쟁체제 도입 전 신규철도운영자의 철도운영 서비스 제공에 필수적인 시설인 역, 차량기지 등에 대한 국가회수 또는 재매입 필요성 등을 제기함으로써 경쟁체제 도입의 성공적 추진을 위한 방향성을 제시하고자 한다. Rail Related Services mean indispensable facilities and services offered to new rail operator in the introduction of rail competition. In this research, firstly I will subdivide this concept(Rail Related Services) into minimum access packages, additional and ancillary services. Secondly I will propose the verification way on the relation of between Rail Related Services and essential facilities. Thirdly I will establish the principle on the scope and price of Rail Related Services which should be offered to the new rail operator. Fourthly I will raise the necessity of withdrawal or repurchase of the essential facilities(station, maintenance facilities, etc ) which is indispensable to new rail operator from incumbent. Lastly I will indicate the direction of successful execution in the introduction of rail competition.

Effect of <i>Acori graminei Rhizoma</i> on Contractile Dysfunction of Ischemic and Reperfused Rat Heart

Kang, Moonkyu,Kim, Jong-Hoon,Cho, Chongwoon,Chung, Hwan-Suck,Yoon, You-Sik,Lee, Youngseop,Hong, Moochang,Shin, Minkyu,Bae, Hyunsu Pharmaceutical Society of Japan 2006 Biological & pharmaceutical bulletin Vol.29 No.3

<P><I>Acori graminei Rhizoma</I> is one of the best-known traditional herbal medicines frequently used for the treatment of cardiovascular symptoms in Asian countries. The anti-ischemic effect of <I>Acori graminei Rhizoma</I> on ischemia-induced isolated rat heart was investigated through analysis of changes in perfusion pressure, aortic flow, coronary flow, and cardiac output. The subjects in this study were divided into two groups, an ischemia-induced group without any treatment (I), and an ischemia-induced group with <I>Acori graminei Rhizoma</I> treatment (I+AGR). There were no significant differences in perfusion pressure, aortic flow, coronary flow, or cardiac output between the two groups before ischemia was induced. The supply of oxygen and buffer was stopped for 10 min to induce ischemia in isolated rat hearts, and <I>Acori graminei Rhizoma</I> was administered while inducing ischemia. The data showed that <I>Acori graminei Rhizoma</I> treatment significantly prevented decreases in perfusion pressure, aortic flow, coronary flow, and cardiac output under an ischemic condition. In addition, hemodynamics (except heart rate) of the AGR-treated group was significantly recovered 60 min after reperfusion compared to the control group, (systolic aortic pressure: 85.5% <I>vs.</I> 62.5%, aortic flow volume: 68.1% <I>vs.</I> 49.4%, coronary flow volume: 86.8% <I>vs.</I> 60.1%, and cardiac output: 73.1% <I>vs.</I> 54.1%, <I>p</I><0.01). These results suggest that <I>Acori graminei Rhizoma</I> has distinct anti-ischemic effects.</P>

경춘선 이용증대 방안

최문규(MoonKyu Choi),송성태(SeongTae Son),유일선(ILLSun Yu),박상구(SangKu Park),장호환(HoHwan Jang),차효정(HyoJung Cha) 한국철도학회 2012 한국철도학회 학술발표대회논문집 Vol.2012 No.10

2010년 12월 21일 경춘선 복선전철의 완전개통으로 인하여 당초 상봉~춘천간 100분에 운행되던 열차가 ITX 좌석형 급행열차 운행으로 용산~춘천간은 73분, 청량리~춘천간은 57분에 주파하는 등 춘천과 강원권의 관광산업에 획기적인 영향을 주고 있다. 하지만 경춘선 노선이 수도권 북부 및 경기 동북부에 편중되어 있는 관계로 최대의 수요유발 지역이라고 할 수 있는 강남권 및 수도권 동남부 지역에 대한 철도 이용객을 끌어 들이지 못하는 것도 또한, 사실이다. 이에 강남권 및 수도권 동남부 지역의 철도 이용객 NEEDS를 객관적인 정량화를 위하여 설문조사를 실시하고, NEED를 충족시킬 수 있는 경춘선 접근성 향상을 위해 현재 추진 중인 광역철도의 조기개통 및 수도권 순환철도 연결 등을 제시하여 강남권 등 수도권 지역의 철도 이용객이 만족할 수 있는 경춘선 이용 증대방안을 마련코자 한다. Gyeongchun double track line was completely open in Dec.21,2010. The time which originally cost 100 minutes for Sangbong-Chuncheon became 73 minutes for Yongsan-Chuncheon and 57 minutes for Cheongnyangni-ChunCheon with the start of ITX seat express train service, and it brought epoch-making influences to the tourism of Chuncheon and Gangwon area. However, since Gyeongchun line is located too much toward the north capital area and northeast of Gyeonggi, so it could not attract railway users of Gangnam and southeast capital area which could be considered the area with the most needs for railway service. Thus, for the objective quantification of Gangnam area and southeast capital area railway user’s needs, surveys are to be carried out, and in order to increase the accessibility of Gyeongchun line and meeting the& & user’s needs, early opening of currently promoting sustainable railway and connection to the capital area circular railway are to be suggested, so to draw up the Gyeongchun line use increase plan which could satisfy the railway users of all capital area including Gangnam etc.

Nelumbinis Semen reverses a decrease in hippocampal 5-HT release induced by chronic mild stress in rats

Kang, Moonkyu,Pyun, Kwang-Ho,Jang, Choon-Gon,Kim, Hyuntaek,Bae, Hyunsu,Shim, Insop Wiley (Blackwell Publishing) 2005 Journal of pharmacy and pharmacology Vol.57 No.5

Resiquimod, a TLR7/8 agonist, promotes differentiation of myeloid-derived suppressor cells into macrophages and dendritic cells

Lee, Moonkyu,Park, Chan-Su,Lee, Young-Ran,Im, Sun-A,Song, Sukgil,Lee, Chong-Kil 대한약학회 2014 Archives of Pharmacal Research Vol.37 No.9

Myeloid-derived suppressor cells (MDSCs) accumulate in cancer patients and tumor-bearing mice, subsequently suppressing the host immune system. MDSCs represent a group of immature myeloid cells expressing CD11b and Gr-1. Here, we show that a Toll-like receptor (TLR) agonist, resiquimod, which binds to TLR7 and TLR8, induces the differentiation of MDSCs into mature myeloid cells. MDSCs were isolated from mice bearing mammary carcinoma 4T1 cells, and the purified MDSCs were cultured in the presence of resiquimod for 5 days. Phenotypic analysis showed that the resiquimod-treated MDSCs differentiated into $F4/80^+$ macrophages and $CD11c^+/I-Ad^{d+}$ dendritic cells. Functional analysis showed that the MDSCs also lost their suppressive activity on T cells. Resiquimod-treated MDSCs significantly enhanced the proliferation of T cells that were treated with anti-CD3 and anti-CD28 monoclonal antibodies. These results show that resiquimod induces the differentiation of MDSCs into macrophages and dendritic cells, and also suggest that resiquimod may improve cancer immunotherapy by reducing immunosuppressive MDSCs.

Anti-ischemic effect of Aurantii Fructus on contractile dysfunction of ischemic and reperfused rat heart

Kang, Moonkyu,Kim, Jong-Hoon,Cho, Chongwoon,Chung, Hwan-Suck,Kang, Chang-Woon,Kim, Yangseok,Shin, Minkyu,Hong, Moochang,Bae, Hyunsu WHO COLLABORATING CENTRE FOR TRADITIONAL MEDICINE 2007 東西醫學硏究所 論文集 Vol.2007 No.-

Aurantii Fructus (AF) is one of the most well-known traditional herbal medicines frequently used for the treatment of cardiovascular symptoms in Korea. The anti-ischemic effects of AF on ischemia-induced isolated rat heart were investigated through analyses of changes in perfusion pressure, aortic flow, coronary How, and cardiac output. The subjects in this study were divided into two groups: an ischemia-induced group without any treatment, and an ischemia-induced group with AF treatment. There were no significant differences in perfusion pressure, aortic How, coronary flow. and cardiac output between them before ischcmia was induced. The supply of oxygen and buffer was stopped for 10 min to induce ischemia in isolated rat hearts, and AF was administered during ischemia induction. AF treatment significantly prevented decreases in perfusion pressure, aortic How, coronary flow, and cardiac output under ischemic conditions (P<0.01).These results suggest that AF has distinct anti-ischemic effects through recovery of contractile dysfunction in ischemic heart.

The piezoresponse force microscopy investigation of self-polarization alignment in poly(vinylidene fluoride-<i>co</i>-trifluoroethylene) ultrathin films

Park, Moonkyu,Choi, Yoon-Young,Kim, Jiyoon,Hong, Jongin,Song, Han Wook,Sung, Tae-Hyun,No, Kwangsoo The Royal Society of Chemistry 2012 SOFT MATTER Vol.8 No.4

<P>We report the self-polarization alignment without external poling in spin-coated poly(vinylidene fluoride-<I>co</I>-trifluoroethylene), P(VDF-TrFE), thin films on transparent and flexible substrates. Piezoresponse force microscopy (PFM) allows the quantitative analysis of preferentially aligned polarization in the ferroelectric thin films. We found that as-received P(VDF-TrFE) thin films on transparent poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) electrodes showed stronger self-polarization alignment than those on indium-tin oxide (ITO) electrodes. The relative ratios for the aligned polarization per unit volume on PEDOT:PSS and ITO electrodes were 18.6% and 4%, respectively.</P> <P>Graphic Abstract</P><P>Piezoresponse force microscopy (PFM) has been utilized to quantitatively assess an amount of self-polarization in the organic ferroelectric ultrathin films on different bottom electrodes. Importantly, the work function of bottom electrode played a significant role in this self-polarization. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c1sm05950e'> </P>

Effects of Yukmijihwang-tang Derivatives (YMJd) on Ibotenic Acid-Induced Amnesia in the Rat

Kang, Moonkyu,Kim, Ji-Hyun,Cho, Chongwoon,Lee, Kwang-Yeun,Shin, Minkyu,Hong, Moochang,Shim, Insop,Bae, Hyunsu Pharmaceutical Society of Japan 2006 Biological & pharmaceutical bulletin Vol.29 No.7

<P>The present study investigates the effects of Yukmijihwang-tang Derivatives (YMJd) on learning and memory through the Morris water maze task and the central cholinergic system of rats with excitotoxic medial septum (MS) lesion. In the water maze test, the animals were trained to find a platform in a fixed position for 6 d and then received a 60-s probe trial in which the platform was removed from the pool on the 7th day. Ibotenic lesion of the MS showed the impaired performance in the Morris water maze test and severe cell losses in the MS, as indicated by decreased choline acetyltransferase-immunoreactivity in the medial septum. Daily administrations of YMJd (100 mg/kg, i.p.) for 21 consecutive days produced significant reversals of ibotenic acid-induced deficit in learning and memory. These treatments also reduced the loss of choline acetyltransferase (ChAT) immunoreactivity in the MS induced by ibotenic acid. These results suggest that impairments of spatial learning and memory might be attributable to the degeneration of septohippocampal cholinergic (SHC) neurons and that YMJd treatment ameliorated learning and memory deficits partly due through neuroprotective effects on the central acetylcholine system. Our studies suggest that YMJd might be useful in the treatment of Alzheimer's disease.</P>

무지개 생성 원리 분석을 위한 유리구슬 무지개 실험장치 개발

손문규 ( Moonkyu Son ),권문호 ( Munho Kwon ),최호명 ( Ho-meoyng Choi ) 경북대학교 과학교육연구소 2021 科學敎育硏究誌 Vol.45 No.3

본 연구에서는 무지개의 생성 원리를 분석할 수 있는 무지개 발생 장치를 개발하였다. 무지개는 물방울에 대한 빛의 분산 및 반사와 굴절에 의해 형성되지만, 물방울 한 개로만 무지개를 만들 수 없다. 따라서 본 연구에서는 여러 물방울들이 만드는 빛의 경로를 통해 무지개를 관측할 수 있는 장치를 만들어 무지개 생성 원리에 대해 학생들이 보다 쉽게 이해하도록 하였다. 물방울이 만드는 무지개는 유리구슬을 이용하여 재현하였고, 관찰자의 위치와 광원의 고도 등과 같은 무지개 생성과 관련된 다양한 변인을 변화시키며 무지개를 구현하였다. In this study, we developed an experimental apparatus to study the principle of rainbow formation. The rainbow is formed through the dispersion, reflection, and refraction of light on water droplets. However, the rainbow cannot be made from a single drop of water. Thus, we devised an apparatus to observe the principle behind the rainbow formation caused by light rays on many water drops. This we deemed would help students understand the formation of the rainbow. We used glass beads as water drops to reproduce the rainbow phenomena. We also materialized the rainbow by changing various variables such as the position of the observer and the height of the light source, etc.