Inhibitory effect of long-term and low temperature fermented Ginseng on passive cutaneous anaphylaxis

Hwang, Seonweon Graduate School, Yonsei University 2019 국내박사

Ginseng (the root of Panax ginseng C.A. Meyer) is a well-known Korean traditional medicine in the Far East and has gained popularity in the west in the last decade. Ginseng has been widely reported to possess various biological activities, including anti-oxidant, anti-cancer, and anti-inflammatory activities. Ginseng contains various phytochemicals, such as ginsenosides (saponins), polyacetylenes, and polyphenolic compounds. Among them, the major components are ginsenosides, which are glycosides with steroids or triterpenes as aglycons. These ginsenosides are an important class of physiologically active compounds found in many herbs which possess anti-inflammatory and anti-tumor activities, such as the inhibition of tumor-induced angiogenesis and the prevention of tumor invasion and metastasis. Recently, studies have been actively carried out to develop highly- functional ginseng products by combining new technologies that maximize the efficacy of ginseng. Fermented ginseng, which changes the structure of ginsenosides through fermentation using enzymes and microorganisms, has received much attention. However, the effect of ginseng fermented by Lactobacillus plantarum on allergic responses has not been elucidated. In the present study, for fermentation, ginseng was incubated with L. plantarum at low temperature (4°C–10°C) for a long time (100 days). The amounts and types of ginsenosides in fermented ginseng extract (FPG) were assessed and compared with their corresponding values in the ginseng extract (PG). Any change in the composition of ginsenosides due to fermentation was also investigated. In the fermentation product, Rb1 (94%), Rg1 (61%), and Rc (50%) were decreased. However, the ginsenosides Rh2, Rh3, and Rk2 were newly detected, and the amounts of the ginsenosides Rd (1.7 time), Rh1 (6.5 time), and F1 (35 time) were increased. Anti-allergic effects of FPG in immunoglobulin E (IgE)-mediated murine cell line in vitro and passive cutaneous anaphylaxis in vivo were investigated. FPG showed higher inhibitory effect than PG against allergic responses in vitro and in vivo. The secretion of β-hexosaminidase and interleukin (IL)-4 from IgE-dinitrophenyl (DNP)-stimulated RBH-2H3 mast cells was significantly (p < 0.05) inhibited by FPG treatment in a concentration dependent manner. Further, mitogen-activated protein kinase kinase 4 (MKK4) activation and c-Jun N-terminal kinase (JNK) phosphorylation, which is the subsequent signal of MKK4, were attenuated by FPG treatment. The superior inhibitory effect of FPG compared with that of PG on allergic response was confirmed by IgE-DNP-induced passive cutaneous anaphylaxis in mouse in vivo model. Accordingly, the fermentation of ginseng with L. plantarum possesses anti-allergic effects in vitro and in vivo conditions. Therefore, it is anticipated that fermented ginseng can be used as a natural material for anti-allergic disorders.

The Impact of Using Advance Organizers On EFL College Students' Listening Comprehension

Jungja Hwang 경희대학교 2015 국내석사

ABSTRACT Jungja, Hwang Department of British-American Language & Culture Graduate School of Kyung Hee University Listening plays a significant role in the language acquisition process and in communication, and its development as a foreign language skill has gradually become of a chief concern to foreign language learners. In spite of its importance, EFL learners often regard listening as the most difficult language skill. The purpose of this study was to investigate what kind of advance organizers is the most effective in making aural input more comprehensible to Korean EFL college students, and to identify their attitudes towards various listening aids. The study focuses on the effects of three different types of written advance organizers, including key Vocabulary Previewing (VP), key Phrases or Sentences Previewing (PSP), and key Questions Previewing (QP) on EFL learners’ listening comprehension. A total of fifty-three second-year college school students with low listening proficiency in two intact classrooms were assigned to one control group and one experimental group at the beginning of the second term in 2014. Prior to the treatment, the experimental and control groups were pretested. During the 12 week long class taught 3 hours a week, the experimental group received a list of vocabulary items (Vocabulary Pre-teaching, VP), a list of key phrases or sentences (Phrases or Sentences Previewing, PSP), and a list of key questions (Question Previewing, QP). The control group did not receive any kind of advance organizer. After the treatment, the experimental group was again measured on a posttest to compare their improvement in listening comprehension using a standardized TOEIC. The results of the statistical analysis were calculated (Independent t-tests, Dependent t-tests, and ANOVA) with SPSS 20.0 and revealed that students who received advance organizers demonstrated statistically significant improvement on the listening comprehension posttest. However, the control group was statistically meaningful. The results showed that the most effective type of activity was VP, followed PSP. The interviews with the students also revealed that they thought that vocabulary pre-teaching is the most effective activity. It is concluded that allowing students to study vocabulary and phrases and sentences before a test could improve their vocabulary knowledge. Based on the students’ responses in the questionnaire and reports in their interviews, using an advance organizer in English class is effective to help listening comprehension of Korean college students. The results suggest that instructors, and especially those who teach college students in Korea, should think about using diverse advance organizers, but should also give attention to the kind of advance organizer they choose in order to maximize the improvement of the English listening comprehension of their learners.

Confucianism in modernization : comparative study of China, Japan and Korea

Hwang UMI 1990 국내박사

Electroacupuncture as a complement to usual care for patients with non-acute pain after back surgery : a study protocol for a pilot randomised controlled trial

황만석 Pusan National University 2015 국내박사

서론 요추 수술 후 요통이 재발 또는 지속되는 경우는 흔한 편이나 일반적으로 통증이 잘 조절되지 않는다. 이전의 연구를 살펴보면, 비급성의 요추 수술 후 통증 환자에 대한 질높은 무작위 대조 임상시험은 잘 검색되지 않는다. 본 무작위 대조 임상시험 프로토콜은 전침이 요추 수술 후의 통증 치료 및 요부 기능을 향상시킬 수 있는지를 설명할 수 있는 디자인이다. 방법 및 분석 본 연구는 무작위화된 전침 중재의 평가자 눈가림 예비 임상시험이다. 요추 수술 후 재발 또는 지속되는 요통 환자 (Pain intensity : ≥ VAS 50mm) 들은 무작위로 전침 + 통용 관리 그룹 (EA+UC group) 또는 통용 관리 그룹 (UC group) 에 할당된다. 양 그룹에 할당된 환자는 모두 무작위 배정시부터 4 주 치료 기간 동안 물리 치료와 환자 교육을 포함하여 일반적인 관리를 일주일에 두 번 받아야 한다. 전침+통용 관리 그룹에 할당 된 환자는 4 주 치료 기간 동안 일주일에 두 번 전침 치료가 추가로 있을 것이다. 일차 평가지표는 요통에 대한 VAS로 측정되고, 이차 평가 지표는 EQ-5D과 ODI로 측정된다. 일차 및 이차 결과는 치료 종료 후 4, 8 주에 측정된다. 토론 본 임상시험 프로토콜은 일반적인 임상 상황과 유사하게 하기 위해 비교 효과 시험의 디자인으로 설계되어 있다. 전침 치료시 환자의 증상에 따라 개인화된 경혈 침술의 실제 임상 환경을 반영하고 있다. 본 예비 연구는 미래의 대규모 임상시험의 타당성을 평가하는 데 필요한 임상 기준과 정보를 제공 할 것으로 기대하고 있다.

Electronic correlations in graphene studied using angle-resolved photoemission spectroscopy

황진웅 부산대학교 대학원 2019 국내박사

Strong electronic correlations have been a fascinating theme in condensed matter physics over the past decades. Indeed, tons of research have been performed to create and manipulate such correlations by introducing localized orbitals to investigate the Kondo effect or heavy fermions, and to examine the Mott insulators or charge/spin-density waves with triggering the structural instabilities. Another beautiful and simple way to implement the strong electronic correlations is to lower the dimension of a system. As the dimension decreases, the interactions of charge, spin, and lattice vibrations become very sensitive to thermal and quantum fluctuations. Hence, a two-dimension (2D) system is possible to host novel phenomena that its three-dimensional counterpart cannot exhibit. However, plausible routes to realize such phenomena and their experimental evidences still remain unveiled. Thus, the essential question is how to realize strong electronic correlations in the 2D system and how to manipulate the fundamental physical properties. In this dissertation, the electronic correlations in graphene, a prototypical two-dimensional system, were investigated by using angle-resolved photoemission spectroscopy (ARPES). First, electron-electron interactions in charge neutral graphene were investigated by using an SrTiO3 substrate. The observed electron band structure of graphene shows strong deviation from the characteristic linearity at low temperatures, suggesting a possible realization of strong correlations among Dirac fermions at low temperatures. Second, the Kondo effect has been explored for the Ce-intercalated graphene on an SiC(0001) substrate. The ARPES results show that the Ce-induced localized states near Fermi energy are hybridized with the graphene π band and exhibit gradual increase in spectral weight upon decreasing temperature. The observed temperature-dependence reveals a direct evidence of the Kondo resonance induced by graphene π electrons that antiferromagnetically screen the localized spin of the 4f electron of a cerium atom at low temperature. These findings provide a novel insight for the role of substrates and adatoms on the electronic properties of graphene.

Studies on gasification efficiency : experimental and numerical investigations on fuel, gasifier, and cyclone

황인식 Graduate School, Yonsei University 2021 국내박사

Owing to the increasing demand to mitigate the greenhouse effect, which is a crucial environmental problem, gasification technology has been favored. The gasification process, although old, still have to solve several practical issues such as high cost, low efficiency, full applicability of the process, optimization, stable operation, tar formation. Therefore, it needs to develop method to increase gasification efficiency and optimize the gasification technology. Simulating gasification technology based on available experimental data can become an alternative to support process optimization and contribute to improved gasification technology. Therefore, in this study, several CFD models are introduced to investigate fluidized bed gasification technology. Furthermore, to overcome current biomass gasification technology drawbacks, co-gasification of coal and biomass is experimentally investigated to bridge energy production based on fossil and renewable energy. In chapter2, catalytic co-gasification of coal-biomass with CO2 is experimentally investigated. Different amounts of various catalytic metal species are loaded on coal–biomass mixture (4:1) samples. Each sample is pyrolyzed and subsequently gasified with CO2. Potassium (K) is determined to be the catalytic metal species that increases the gasification reactivity the most, followed by other species in the order K > Na > Fe > Ca > Mg > Non-catalytic. As the loading amount of catalytic metal species increases, the gasification reactivity increases; however, it does not change once the loading amount of catalytic metal species reaches a certain value. Among the various kinetic models, the modified volume reaction model describes the gasification reactivity for catalytic gasification well. In chapter3, air-blown gasification of biomass in a bubbling fluidized bed (BFB) gasifier is numerically investigated. A discrete element model coupled with computational fluid dynamics (CFD-DEM) is employed in a pilot-scale BFB gasifier (1 t/day) located in Korea Institute of Industrial Technology (KITECH), Cheonan, South Korea. Numerical calculation is performed under a given operating condition. Subsequently, the flow and characteristics of the BFB are discussed and compared with the reported experimental data. Furthermore, calculations are performed for different operating conditions and compared with reported experimental data. After the results are validated with respect to the reported experimental data, the gasification performance of the BFB is discussed for cases with varying fluidization number (FN) values at a constant equivalence ratio (ER). The calculated results indicate that an increase in FN beyond a certain value is not recommended. Finally, various combinations of FN and ER values at a constant biomass-feeding rate are considered. The calculated results show that an optimum combination of FN and ER values exists at a constant biomass-feeding rate. Then, tar models are applied to validated model. Through proposed gasification model including tar formation model, syngas composition, gas temperature profiles, and tar concentrations are investigated. Furthermore, the effects of side feeding system are analyzed to reduce tar formation. In chapter4, as one of components in fluidized bed system, cyclone is investigated using numerical simulation. At a high solid volume fraction, four-way coupling must be applied to account for solid volume fraction in Navier-Stokes equations and particle-particle collisions, which are not considered in one- and two-way couplings approaches. A four-way coupling method, the dense discrete phase model (DDPM), which accounts for the solid volume fraction, is used in this study. The kinetic theory of granular flow (KTGF) in the DDPM is utilized to compute particle-particle interactions. The calculated results obtained using DDPM-KTGF are validated using experimental results reported previously. These results are compared with numerical data obtained from the discrete element model (DEM), which is another four-way coupling method. DDPM-KTGF could be successfully applied to situations involving high solid volume fractions with a significantly lower computational time than that required for DEM. Furthermore, the effect of the vortex finder (VF) length on the cyclone performance in a 340-MWe CFB boiler operated by Korea South-East Power Corporation is analyzed using computational fluid dynamics. As the VF length decreases, the unexpected short-circuit flow around the VF reduces the pressure difference between the center and the cyclone wall. This reduces the swirl intensity, decreasing the natural vortex length. As the VF length increases, the short-circuit flow decreases, along with the pressure difference and swirl intensity, reducing the natural vortex length. Thus, increasing the VF length beyond a certain value is not recommended, and there is an optimum VF length for maximizing the cyclone collection efficiency.

Preparation and evaluation of ophthalmic liposomal voriconazole formulation by thin film hydration method

황금길 Graduate School, Yonsei University 2018 국내석사

1. Introduction Fungal keratitis is one of infectious corneal diseases and is an increasing disease in developing countries. And the incidence is increasing in developed countries due to increased use of contact lenses. To treat this, antifungal agents are used, typically natamycin and amphotericin B. However, its use is limited because of the narrow range of antifungal agents and low permeability. Voriconazole, a second-generation azole antifungal agent with a broad range of antifungal agents, is under investigation. The limitation of Voriconazole is that it has low water solubility and poor cornea permeability. Liposome as nano-carrier can be used to overcome this problem. Voriconazole can be encapsulated between phospholipids of liposome to enhance permeability while increasing solubility. There are various ways of making liposomes. Among the various methods of making liposomes, liposomes were prepared by the commonly used thin film hydration method. Therefore, the goal of this paper is to develop a liposomal formulation of voriconazole with broad spectrum antifungal activity, which is increased water solubility and permeability, thereby increasing the BA of voriconazole and ultimately increasing therapeutic efficiency. 2. Preparation of liposome We prepared liposome by thin film hydration. Formulations of Increasing the organic solvent amount and molar ratio of HSPC were prepared. And we also prepared formulations containing a mPEG-DSPE, SA for positively charged liposome, and DP for negatively charged liposome. Cholesterol was added to find out effect of cholesterol to liposome. 3. Evaluation of liposome Organic solvent amount did not affect to size, zeta potential, assay%, EE%. Increasing molar ratio of HSPC affect to the size, PDI, and pH. Cholesterol did not affect to liposome size, PDI and assay%, EE%, also. Formulation with SPC was viscous and size was largest. mPEG-DSPE makes zeta potetial of liposome to negative charge but stearylamine makes zeta potential to positive. Dicetylphosphate makes liposome acidic but stearylamine makes liposome basic. Voriconazole assay % was almost 100% and EE% was almost 94% in all formulation. Specially formulation with mPEG-DSPE showed 99% of EE%. In the DSC data, voriconazole peak and cholesterol peak was disappeared in all formulations. In vitro release data described that all liposome formulation has higher dissolution rate than 1% voriconazole suspension. Formulation with mPEG-DSPE, Chol shows the higher dissolution rate. And permeation study with bovine cornea described that permeation rate followed the zeta potential. Formulation 12, and 15 have higher permeation rate and stearylamine formulation with positive zeta potential show lowest permeation rate. 진균 각막염은 감염성 각막 질환 중 하나이며 개발 도상국에서 증가하는 질병이다. 그리고 콘택트 렌즈의 사용 증가로 인해 선진국에서는 그 빈도가 증가하고 있다. 이를 치료하기 위해 일반적으로 natamycin과 amphotericin B와 같은 항진균제가 사용된다. 그러나 이들 항균제들은 항균 범위가 좁고 각막 침투성이 낮기 때문에 사용이 제한됩니다. 보리코나졸 (Voriconazole)은 다양한 종류의 항진균 범위를 가진 2 세대 azole계 항진균제이다. 보리코나졸의 사용 제한점은 용해도가 낮고 수분 안정성이 낮다는 것이다. 이 문제를 극복하기 위해 나노 운반체 인 리포좀을 사용할 수 있다. 보리코나졸은 리포솜의 인지질 사이에 encapsulation 되어 안정성이 높아지고 용해도도 높아질 수 있다. 리포솜을 제조하는 다양한 방법 중에서, 일반적으로 사용되는 thin film hydration법으로 리포좀을 제조 하였다. 따라서 본 연구의 목적은 용해도 및 투과성이 증가 된 광범위한 항진균 활성을 갖는 보리 코나 졸의 리포좀 제형을 개발함으로써 보리 코나 졸의 BA를 증가시키고 궁극적으로 치료 효율을 증가시키는 것이다. 2. 리포솜의 제조 Thin film hydration법을 리포솜을 만들었다. HSPC의 유기 용매량 및 몰비를 증가시키는 표뮬레이션을 개발 하였다. 그리고 우리는 또한 mPEG-DSPE, 양전하를 띤 리포솜을 위한 SA 및 음전하를 띠는 리포솜을 위한 DP를 함유하는 제제를 만들었다. 콜레스테롤이 리포솜에 대한 콜레스테롤의 효과를 알아 내기 위해 첨가되었습니다. 3. 리포좀의 평가 유기 용매의 양은 particle mean size, zeta potential, assay%, EE %에는 영향을 미치지 않았다. HSPC의 증가하는 몰 비율은 particle mean size, PDI, pH에 영향을 미친다. 콜레스테롤은 리포좀 mean size, PDI 및 assay%, EE%에도 영향을 미치지 않았다. SPC를 사용한 제제는 점성이 크고 입자 크기가 가장 컸다. mPEG-DSPE는 리간드의 제타 전위를 음전하로하지만 stearylamine은 리포솜의 zeta potential을 양전하로 만든다. dicetylphosphate는 리포좀을 산성으로 만들지만 stearylamine은 리포좀을 염기성으로 만든다. Voriconazole assay%은 거의 100 % 였고 EE %는 거의 모든 포뮬레이션에서 거의 94 %였다. 특히 mPEG-DSPE를 사용한 제제는 99 %의 EE %를 나타냈다. DSC 데이터에서 모든 포뮬레이션에서 보리코나졸 peak와 콜레스테롤 peak가 사라졌다. Drug release study는 모든 리포좀 제형이 1 % 보리코나졸 현탁액보다 높은 용출률을 갖는 것을 의미했다. Chol과 mPEG-DSPE을 함유한 포뮬레이션은 더 높은 용출률을 나타냈다. 소의 각막을 이용한 permeability study에서 permeability rate가 zeta potential과 비례한다고 할 수 있다. 포뮬레이션 12, 포뮬레이션 15는 보다 높은 permeability rate를 가지며, 양의 zeta potential을 갖는 stearylamine 포뮬레이션은 가장 낮은 투과 속도를 나타냈다.

Numerical and Experimental study on characteristics of cone-jet mode in Electrohydrodynamic jet

황준원 Graduate School, Yonsei University 2010 국내석사

Electrohydrodynamic(EHD) deals with fluid motion induced by electric field. When a liquid is subject to a sufficiently strong electric field, it can be induced to emit thin fluid jets from conical tip structures that form at its surface. It is also considered as that part of electrohydrodynamics which is involved with the influence of moving media on electric fields. According to given condition, various modes of EHD jet are exist: microdripping mode, stable cone-jet mode, multi-jet mode. But to apply a EHD technology in engineering fields, we need a stable cone-jet relatively easy to control. There are many parameters to get cone-jet mode in EHD jet, but it is hard to control desired parameters in experiment. So the formation of an Electrohydrodynamic jet from a nozzle is investigated numerically. The numerical model presented, using COMSOL Multiphysics, can predict the behavior of liquid cone-jet with respect to various parameters in EHD jet for operating parameters, mixture properties and dimensions. Electric forces are calculated by the Maxwell stress tensor. The numerical model is able to calculate the on-set voltage of cone-jet, shape of the liquid cone and the resulting jet, space charge density distribution, the electric fields distribution inside and outside the cone-jet. The effects of potential difference, flow rate and properties of the liquid on the EHD jet behavior are investigated. The mathematical formulas with proper governing equation and boundary conditions for the relevant physics processes are described in detail.

Sargassum fulvellum extract and its active compound Fucosterol attenuate skeletal muscle atrophy by activating the PI3K/Akt pathway

황지은 Graduate School, Yonsei University 2017 국내석사

근위축증은 근섬유의 크기와 수의 감소로 정의되며 부동화, 노화, 만성질환과 같은 원인에 의해 발생한다. 근위축증은 기대수명, 삶의 질, 이동성의 감소를 야기한다. 모자반(Sargassum fulvellum)은 모자반과 갈조류로서 항암, 항산화, 항염 등의 생리활성이 알려져 있다. Fucosterol은 식물성스테롤로서 모자반이나 미역 등의 갈조류로부터 분리되며 생리활성으로 항당뇨, 항산화, 항염 등이 알려져 있다. 그러나 모자반과 그의 활성성분 fucosterol의 근위축증 개선 효과에 대한 연구는 진행된 바 없다. 본 연구에서는 모자반 추출물(S. fulvellum extract; SFE) 및 fucosterol의 근위축증 억제 효과 및 근기능 증진 효과를 tumor necrosis factor-alpha (TNF-α)를 처리한 마우스 근관세포(C2C12 myotube)세포와 부동화된C57BL/6J 마우스의 뒷다리 근육에서 검증하였다. 분자적 수준에서, SFE와 fucosterol은 세포모델과 동물모델에서 전염증성 싸이토카인 TNF-α와 interleukin-6 (IL-6)의 발현을 억제시켰으며, phosphatidylinositol 3-kinase (PI3K)/Akt를 활성 시키는 것을 통해 mammalian target of rapamycin (mTOR)신호전달체계를 조절시켜 근단백질 합성을 촉진하고 forkhead box O3a (FoxO3a)의 전사 과정을 조절하여 atrogin-1과 muscle ring finger 1 (MuRF1)의 발현을 감소시켜 근단백질 분해를 억제시켰다. 동물모델에서 SFE와 fucosterol은 근육부피, 근육량, 근단면적을 증가시켜 근력을 회복시켰다. 이 결과는 SFE와 fucosterol이 PI3K/Akt 신호전달체계를 타겟팅하여, 근위축증을 억제하고 근기능을 증진시키는 것을 입증한다. 따라서 SFE와 fucosterol은 근위축증을 억제하고 근기능을 증진시키는 소재로서 응용될 수 있을 것으로 기대된다. Muscle atrophy, characterized by a reduced size and number of myofibers, occurs by immobilization, aging, and several chronic diseases. Muscle atrophy results in declining in life expectancy, quality of life, and mobility. Sargassum fulvellum, commonly called Mojaban in Korea, belongs to the brown algae of Sargassaceae family. It reportedly has anti-cancer, anti-oxidative, anti-pyretic, and anti-inflammatory activities. Fucosterol is a phytosterol isolated from brown algae such as S. fulvellum and Undaria pinnatifida with reported activities including anti-cancer, anti-diabetes, anti-oxidation, and anti-inflammation. However, there have been no studies on effects of S. fulvellum and its active compound fucosterol on muscle atrophy and the muscle function. This study examined whether S. fulvellum ethanol extract (SFE) and fucosterol attenuated skeletal muscle atrophy in C2C12 myotubes treated with tumor necrosis factor-alpha (TNF-α) and immobilized hindlimb muscles of C57BL/6J mice. At the molecular level, SFE and fucosterol inhibited the expression of TNF-α and interleukin-6 (IL-6) which are proinflammatory cytokines that accelerate muscle atrophy. SFE and fucosterol increased muscle protein synthesis by upregulating the mammalian target of rapamycin (mTOR) pathway and downregulated proteolysis-related biomarkers such as forkhead box O3a (FoxO3a), atrogin-1, and muscle ring finger 1 (MuRF1) by stimulating the phosphatidylinositol 3-kinase (PI3K)/Akt pathway in vitro and in vivo. SFE and fucosterol significantly restored the muscle strength by increasing the muscle volume, mass, and myofiber cross-sectional area in mice. These results demonstrate that SFE and fucosterol attenuate muscle atrophy and improve the muscle function by targeting the PI3K/Akt pathway. So, SFE and fucosterol could be used as an agent to prevent muscle atrophy and improve the muscle function.

InGaZnO based charge trap device for NAND flash memory application

황은석 Seoul National University 2018 국내박사

Current information technology industry requires faster, smaller, less power consuming and cost effective memory devices, which is the fundament of the computer system. Out of many memory devices, NAND flash memory technology one of the promising candidate for next generation storage system. Planar technology is at its roadblocks due to the fundamental limitation of the density per available wafer area. Hence, vertical NAND flash (VNAND) is the solution, which can overcome the density limitation. Current industry use three major types of V-NAND (i.e. BiCs, TCAT and Pipe-BiCs). These major architectures of V-NAND all require “Etch hole”, where ONO, channel and oxide is deposited. Due to limitation on wafer area, etch hole and spacer between etch holes have limitations, often called as the “critical diameter or dimension”. In case of etch hole itself, each packing density has different critical diameter of hole (CD). Currently, a-Si or poly-Si channels are used as the channel material. However, as etch hole depth elongates, to increase cell density, Si based channel suffer from low on current, which can be very problematic in achieving constant device uniformity. To increase on current, Si based channel requires thickening, but again, limited by the CD. Hence, new channel material that can guarantee tunable electrical characteristic is ideal. Out of many candidates, amorphous oxide is one of the promising candidate. InGaZnO (α-IGZO or IGZO) has been well studied to be applied on V-NAND technology. Professor Hosono first proposed IGZO in the year 2004. Since then, IGZO has been intensely studied for its application on display devices. With most common deposition technique, sputtering. Large area, fast deposition rate, and relatively uniform film quality had lead such popularity. In primitive stage of the IGZO research, most problematic characteristic was material’s instability against light illumination under negative bias (NBIS). When light wavelength of 550nm (or shorter) is induced on IGZO (held at negative gate bias), negative shift of the transfer curve was observed. Numerous arguments have been proposed as a possible cause, but most agreed that it was the ionization of the oxygen vacancy. When light is induced, the oxygen vacancy (naturally occurring from amorphous large band gap nature of the material) begins to ionize, changing its valance state from neutron to two (creating two extra electron). Previous research from our group has shown that NBIS is geometry dependent (NBIS worsen as channel length increase), hence, smaller channel dimension may solve the issue. Other possible solutions were to doping and use passivation layer. Despite its intensive study for display application, IGZO’s application on V-NAND still requires major challenge, to change deposition technique. Despite fast and low temperature merits of the sputtering process, its low step coverage hinders IGZO for the memory applications. In this sense, this research proposes relatively new deposition technique to deposit IGZO: metal-organic chemical vapor deposition (MOCVD). First part of this research compares program and erase characteristics of MOCVD and sputter deposited a-IGZO. Both deposition methods have shown to have similar atomic percent (stoichiometry), density and thickness. Despite, slightly higher saturation mobility from sputter IGZO, the program and erase characteristics showed much faster operation in case for the MOCVD IGZO (PGM 3.12V @ VPGM=20V,tPGM=100ms for MOCVD and PGM 1.63V @ VPGM=20V, tPGM=100ms). In depth analysis of such behavior were studied. Second part concerns the composition variation of the IGZO. MOCVD processed IGZO were studied with different Ga/Zn ratio, keeping the In content at constant (40 atomic percent). Previous research has indicated Ga as the carrier sink, allowing the stable off current of the TFT, due to strong bonding between Ga and O. However, study on different Ga/Zn ratio has indicated while highest field effective channel mobility was observed at max Zn content (of the study), highest saturation mobility was observed when Ga/Zn ratio was at maximum (of the study). Analysis to understand the role of Ga/Zn within the IGZO thin film is further investigated