Characterization study of novel process and high purity-magnesium products recovered from brine and bitterns

Tran, Thi Khuyen Chonnam National University 2016 국내박사

Magnesium is known to be the lightest among the light metals. Due to its light weight and low density, Mg and its compounds have extensively been used in various applications such as in automotive, aerospace, electronics, agricultural and chemical industries, etc. Currently, magnesium is recovered from two major sources, namely seawater/brines/bittern and Mg – containing minerals. In this study, the recovery of Mg as carbonate was conducted using Uyuni salar brine (containing ~13.3 g/kg Mg) from Bolivia and bittern (containing ~41.1 g/kg Mg). Stabcal software was first used to investigate the stability of various magnesium species and Mg carbonate during the precipitation. Depending on the pH of solution, Stabcal predicts the formation of various Mg products such as Mg oxalate, magnesite, hydromagnesite, and magnesium hydroxide. The Mg recovery from Uyuni salar brine was conducted at different stoichiometries of 0.6 – 2.4:1 (corresponding to CO3/Mg molar ratio of 0.5 – 1.9:1) in the meanwhile a stoichiometry of 1:1 was used for the bittern. After precipitation, the solids were washed by distilled water prior to drying at 25, 65, and 100oC. X-Ray Diffraction results obtained for the samples recovered from brine as well as bittern confirmed the formation of dypingite – (MgCO3)4.Mg(OH)2.5H2O or (MgCO3)4.Mg(OH)2.8H2O at ambient temperature precipitation and drying while the drying at 65oC and 100oC formed hydromagnesite – (MgCO3)4.Mg(OH)2.4H2O. Field Emission – Scanning Electron Microscopy analysis showed that a sheet – like morphology was yielded for the hydromagnesite precipitated from the low – oxalate brine as well as bittern at room temperature precipitation and 100oC drying. Differential Thermal Analysis of dypingite – (MgCO3)4.Mg(OH)2.5H2O showed its total mass loss experimentally measured as 58.7 ± 0.1% including adsorbed water, equivalent to 41.2 ± 0.1% MgO in the residue. The total mass losses of hydromagnesite obtained at 65oC and 100oC drying were in the range of 54.8 – 56.7%, corresponding to 45.2 – 43.3% MgO in the residue. Theoretical mass losses of dypingite and hydromagnesesite should be 58.5% and 56.8%, respectively, representing 41.5% and 43.2% MgO in the residue. Chemical analysis showed that the hydromagnesite obtained from low – oxalate brine had a grade of 23.3 – 24.3%, corresponding to a content of 38.7 – 40.3% MgO. Meanwhile a grade of 25.3 – 25.9% Mg (~41.9 – 42.9% MgO) was yielded for hydromagnesite recovered from the high-oxalate brine and a 25.7 – 25.9% Mg (~42.7 – 42.9% MgO) was from bittern. Theoretical hydromagnesite should contain 26.0% Mg, representing 43.1% MgO. Differential Scanning Calorimetry analysis showed that the net endothermic energy released (heat adsorbed) during decomposition of hydromagnesite recovered from the low-oxalate brine was in the range –1173.1 to –1196.1 J/g. In the meanwhile those from high-oxalate brine and bittern were from –972.1 to –1073.8 J/g, and –585.1 to –591.2 J/g, respectively. Hydromagnesite obtained from the low-oxalate brine was found to have a highest endothermic energy.

Study on wafer fusion of GaN/inGaAIP and application to light-emitting diode

Tran, Vinh Hung 전북대학교 대학원 2002 국내석사

베트남 빈증성 지역 진출 한국 자회사의 누적 생존율 및 영향 요인 분석

Tran, Thi Thanh Hang 부경대학교 2018 국내박사

In recent years, Vietnam has continued to attract foreign investment and has joined the Trans-Pacific Strategic Economic Partnership (TTP) and various trade agreements. In particular, since the Korea-Vietnam FTA came into effect in 2015, both the investment and trade volume between Korea and Vietnam have been rapidly increasing. Considering that overseas exits are on the rise in investment in Korea and Vietnam, the survival factors of subsidiaries need to be analyzed. The purpose of this study is to estimate the cumulative survival rate of Korean subsidiaries and analyze the factors affecting the survival rate of subsidiaries through data analysis of 435 Korean subsidiaries that entered in Binh Duong Province between 2005 and 2015. The Kaplan-Meier method was chosen to perform analyses on survival rate and its affecting factors. As a result, findings of the study showed that the business survival rate by the 5 year operating subsidiaries reached 86% and the 10-year cumulative survival rate was 45 %. The result was higher than those of the previous studies in Korea and Vietnam. An empirical analysis on the survival factors of firms used total six explanatory variables such as characteristics of firm(initial investment size, current size, CEO characteristics, investment type) and, regional characteristics(industrial zone vs general area). As a result, initial investment size and current size, investment type and regional characteristics of subsidiaries was positively related with survival rate. But CEO’s gender and nationality was not related with the survival rate of Korean Subsidiaries in Binh Duong Province.

EFFECT OF CHITOOLIGOSACCHARIDE SUPPLEMENTATION ON POULTRY

HOAI NAM TRAN 단국대학교 2017 국내석사

(ABSTRACT) EFFECT OF CHITOOLIGOSACCHARIDE SUPPLEMENTATION ON POULTRY Department of Bio-Resource Science Graduate School Dankook University HOAI NAM TRAN Advisor: Prof. IN HO KIM EXPERIMENT 1: EFFECT OF CHITTOOLIGOSACCHARIDE SUPPLEMENTATION ON PERFORMANCE, BLOOD CHARACTERISTICS, RELATIVE ORGAN WEIGHT, AND MEAT QUALITY IN BROILER CHICKENS This study was conducted to evaluate the effects of dietary supplementation with chitooligosaccharide (COS) on growth performance, blood characteristics, relative organ weight, and meat quality in broilers. A total of 480 broilers with an average initial BW of 45.04 g per chick were randomly allocated into 1 of the following 4 dietary treatments (20 broilers per pen with 6 pens per treatment): 1) CON (basal diet), 2) ANT (basal diet + 44 mg/kg of avilamycin), 3) COS0.2 (basal diet + 0.2% COS), 4) COS0.4 (basal diet + 0.4% COS). The experiment lasted for 5 wk and avilamycin was administered from d 0 to 21. Growth performance was measured on d 0, 21, and 35, and all other response criteria were measured on d 35. No change in feed conversion (G:F) was observed in response to any of the treatments throughout the experimental period (P > 0.05). However, BW gain and feed intake were greater (P < 0.05) in broilers provided with feed supplemented with COS than in those in the control group. In addition, broilers had significantly greater (P < 0.05) red blood cell and high-density lipoprotein cholesterol concentrations when they were provided with the COS0.4 diet, whereas the triglyceride concentration was lower (P < 0.05) in broilers in the COS0.2 treatment group. No other blood characteristics were affected by the treatments. Additionally, as the dietary COS concentration increased, the liver weight increased (P < 0.05). Conversely, as the concentrations of dietary COS increased, abdominal fat decreased (P < 0.05). Furthermore, meat yellowness decreased (P < 0.05) as the concentration of COS increased. Finally, the breast meat and abdominal fat of birds provided with feed supplemented with COS had a lower (P < 0.05) saturated fatty acid concentration but a greater concentration of total monounsaturated fatty acids (P < 0.05) than that of birds in the control. In conclusion, COS can improve the performance and breast meat quality of broilers while increasing the red blood cell and high-density lipoprotein cholesterol concentrations in blood. In addition, COS can induce a decrease in abdominal fat and improve meat quality. EXPERIMENT 2: EFFECT OF CHITTOOLIGOSACCHARIDE SUPPLEMENTATION ON EGG PRODUCTION, NUTRIENT DIGESTIBILITY, EGG QUALITY, AND BLOOD PROFILES IN LAYING HENS This study was conducted to evaluate the effects of dietary supplementation with chitooligosccharide (COS) on egg production, nutrient digestibility, egg quality and blood profiles in laying hens. A total of 240 Hy-line Brown laying hens were randomly allocated into one of the following 5 dietary treatments: i) CON, basal diet; ii) ANT, basal diet+44 mg/kg avilamycin; iii) COS0.2, basal diet+200 mg/kg COS; iv) COS0.4, basal diet+400 mg/kg COS; v) ANTCOS, basal diet+200 mg/kg COS+22 mg/kg avilamycin. The experiment lasted for 6 wk. No change in egg weight (P > 0.05) was observed during the trial period. Egg production in ANTCOS treatment was improved (P < 0.05) when compared to CON during weeks 4-6. The birds in the COS0.2, COS0.4 and ANTCOS groups had higher (P < 0.05) Haugh unit than those fed CON and ANT diets at the end of the 6th wk. The apparent digestibility of nitrogen in CON group was lower (P < 0.05) than in other treatments. The white blood cell (WBC) concentration of birds in the COS0.4 and ANTCOS group was higher (P < 0.05) than that of birds in other groups at the end of the 6th wk. In addition, the differences of WBC counts between the beginning and end of the experiment in COS0.4 and ANTCOS groups were higher (P < 0.05) than in CON and ANT groups. At the end of the experiment, the birds fed ANTCOS diet showed higher (P < 0.05) total blood protein concentration than those fed CON or ANT diets. In conclusion, dietary supplementation of COS appeared to increase egg production and quality by increasing nutrient digestibility. Additionally, COS improved WBC and total protein concentration.

Liquid Phase Sintering of BaY0.1Zr0.9O2.95 Proton Conducting Ceramics

니구겐 트란 휴엔 디에우 전남대학교 대학원 2013 국내석사

Liquid Phase Sintering of BaY0.1Zr0.9O2.95 Proton Conducting Ceramics For Use in Intermediate Temperature Solid Oxide Fuel Cells Huyen Dieu Nguyen Tran Department of Materials Science and Engineering Graduate School Chonnam National University (Supervised by Professor John Fisher) Abstract Ytrria-doped BaZrO3 with the perovskite structure shows potential as a proton conducting electrolyte for solid oxide fuel cells (SOFCs), which represent the state of the art in recent years. The present thesis consists of two research topics concerning Yttria-doped BaZrO3: in the first part, we have presented results on the influence of sintering aids on the densification of polycrystalline BaZr0.9Y0.1O3-δ (BZY10); in the second part, the solid state crystal growth method was used to grow single crystals of BaZr0.9Y0.1O3-δ and the structurally related material SrTiO3. In the first part, powders of BaZr0.9Y0.1O2.95 (BYZ10) were prepared by using the solid-state reaction method with BaCO3, Y2O3 and ZrO2 starting chemicals. The appropriate amounts of Bi2O3, MnCO3 and CuO were then added into the calcined powder as liquid phase sintering aids. The effects of sintering aids on densification, microstructure and electrical properties were studied. Samples were pressed into pellets by cold isostatic pressing at 1500 kg/cm2 (147 MPa) and sintered in the range of temperature from 1400ºC to 1700ºC for 5 hours. Densification of samples was measured by the bulk density method; the density of 3wt% MnCO3 and CuO doped BZY10 reached 93% and 93% theoretical density respectively. The microstructure of samples was studied by scanning electron microscopy (SEM). The structure of the sintered ceramics and the possibility of secondary phases were examined by X-ray diffraction (XRD). All samples were single phase perovskite with cubic structure. Electrical properties of the as-prepared samples was examined below 220?C with impedance spectroscopy. In polycrystalline ceramics, the electrical or ionic conductivity often consists of two components; a bulk conductivity and a grain boundary conductivity. In particular, for acceptor-doped BaZrO3 the grain boundary conductivity is substantially lower than that of the bulk conductivity and dominates the impedance plots. In order to study the bulk conduction mechanisms, it is necessary to grow single crystals of BZY or materials with a similar structure such as SrTiO3. In the second part of this work, the solid-state crystal growth (SSCG) technique is used to grow single crystals of BZY10 and SrTiO3. The principle of the SSCG method is based on inducing abnormal grain growth of the ceramic composition on a seed crystal. This method shows many advantages compared to other single crystal growth techniques e.g. it takes place without melting of the ceramic matrix, it does not need expensive Pts crucible or high temperature processing. Calcined powders of BYZ and Fe-doped SrTiO3 are used to grow single crystals using 8 mol % Yttrium doped ZrO2 and SrTiO3 seed crystals respectively. A single crystal of BZY10 has grown to a thickness of about 5μm on a <100> oriented YSZ seed. Single crystals of Fe-doped SrTiO3 grew to thicknesses of 5 - 25?m on <100> oriented SrTiO3 seeds, with the growth distance varying with sintering atmosphere.

Pomegranate (Punica granatum) Seed Linolenic Acid Isomers : Selective Estrogen Receptor Modulators? = 석류(Punica granatum) 종자유에서 분리된 리노렌산 이성체들의 선택적 에스트로겐 리셉터 수식자 (SERMs) 로의 작용성 : Tran Hoang Ngoc Ai

Hoang, Ngoc Ai Tran 경북대학교 2006 국내석사

퍼지논리를 사용한 로봇 매니퓰래이터 제어기의 적응식 PID 게인 조율 방법에 대한 연구

Tran Anh Dung 한국산업기술대학교 일반대학원 2019 국내석사

ABSTRACT Adaptive PID Gain Tuning Using Fuzzy Logic For Robot Manipulator. by Tran Anh Dung Advisor Prof. Shin Hyeong-ceol, Ph.D Department of Mechanical Engineering. General Graduate School, Korea Polytechnic University The most popularly used form of industrial controllers is Proportional-Integral-Derivative (PID) controller. Nowadays, more than 90% of controllers used in industries are PID or type of PID controller. Because PID controller has simple structure and powerful performance. Though, fixed PID gain do not work well for nonlinear processes or are unable to compensate for disturbances. To address this weakness, many methods for tuning PID gain have been suggested. There is much to gain, if these methods are carried forward to fuzzy logic. In this thesis, a fuzzy adaptive PID gain is proposed for robot manipulators. This method may dynamically adjust proportional coefficient Kp, integral coefficient Ki and derivative coefficient Kd of PID controller by using fuzzy algorithm. The proposed controller has been successfully applied to control SCARA manipulator using Matlab. In this simulation, the external disturbance is addressed. The simulation results have shown that the tracking performance of the fuzzy adaptive PID gain is quite good and more robust and adaptable than traditional PID controller 국문요약 퍼지논리를 사용한 로봇 매니퓰래이터 제어기의 적응식 PID 게인 조율 방법에 대한 연구 한국산업기술대학교 일반대학원 기계공학과: 짠아잉쭝 지도교수: 신 형 철 산업용 컨트롤러 중 가장 보편적으로 사용되는 형태는 PID (Proportional-Integral-Derivative) 컨트롤러입니다. 요즘, 산업계에서 사용되는 컨트롤러의 90 % 이상이 PID 또는 PID 컨트롤러 유형입니다. PID 컨트롤러는 간단한 구조와 강력한 성능을 제공하기 때문에 그러나 고정 PID 게인은 비선형 프로세스에서 잘 작동하지 않거나 장애를 보상 할 수 없습니다. 이러한 약점을 해결하기 위해 PID 이득을 조정하는 많은 방법이 제안되었습니다. 이러한 방법이 퍼지 논리로 이어진다면 얻을 수있는 것이 많습니다. 본 논문에서는 로봇 매니퓰레이터에 대해 퍼지 적응 형 PID 이득을 제안한다. 이 방법은 퍼지 알고리즘을 사용하여 PID 제어기의 비례 계수 Kp, 적분 계수 Ki 및 미분 계수 Kd를 동적으로 조정할 수 있습니다. 제안 된 컨트롤러는 Matlab을 사용하여 SCARA 조작기를 제어하는 데 성공적으로 적용되었습니다. 이 시뮬레이션에서 외란이 해결되었습니다. 시뮬레이션 결과는 퍼지 적응 형 PID 이득의 추적 성능이 기존의 PID 제어기보다 상당히 좋고 견고하고 적응력이 있음을 보여주었습니다.

Antibacterial Effects of Silver Nano-Particles on Bioaerosol Treatment

Tran, Thi Thanh Huyen 세종대학교 대학원 2009 국내석사

패혈증 비브리오균 VarS/VarA two-component system의 분자생물학적 특성 구명

Tran Nguyen Thu Tam 전남대학교 대학원 2009 국내석사

패혈증 비브리오균(Vibrio vulnificus)은 간장질환 등의 기저질환이 있는 환자에서 주로 발생하고 급속히 진행하여 높은 사망률을 나타내는 치명적인 패혈증을 일으키는 호염성 병원성 세균이다. 병원성 세균은 환경의 변화를 인식하여 센서 (histidine kinase)와 반응 조절자 (response regulator) 쌍으로 구성된 다양한 two-component system에 의해 유전자 발현을 특이적으로 조절한다. VarS/VarA two-component system은 대장균(Escherichia coli)의 BarA/UvrY, 살모넬라(Salmonella typhimurium)의 BarA/SirA 및 비브리오 콜레라균(Vibrio cholera)의 VarS/VarA 등 다양한 그람 음성 세균에서 발견되고 있다. 이 시스템은 전사후 조절 기작에 주로 참여하여 일차와 이차 대사 사이의 스위치로서 작동하며 다양한 병원성 세균에서 여러 독력 인자의 발현을 조절하는 것으로 잘 알려져 있다. 본 연구에서는 패혈증 비브리오균에서 VarA homolog(Vv-VarA)를 동정하여 in-frame deletion mutant를 제작하여 그 특성을 구명하였다. Vv-VarA 결손 돌연변이는 투명형으로 집락형태의 변화 및 말기 지수성장기와 초기 정지기 사이에서 성장 결함을 나타냈으며 포유동물세포에 대한 세포 독성 및 마우스에 대한 치사력이 10배정도 감소되는 것으로 확인되었다. 이러한 결과는 VarA system이 패혈증 비브리오균의 독력 조절에 중요한 역할을 하고 있음을 시사한다. Pseudomonas 종의 VarS/VarA system homolog인 GacS/GacA 시스템이 small noncoding RNA RsmY-Z-RsmA의 전사를 조절하는 것으로 알려져 있으며 이는 E. coli의 BarA/UvYY/CsrB/C/CsrA system의 그것과 유사하다. 또한 V. cholerae에서는 VarS/VarA system이 carbon storage regulator protein인 CsrA에 결합하는 small noncoding RNA인 CsrB, CsrC 및 CsrD의 전사를 활성화 시키는 것으로 알려져 있다. 패혈증 비브리오균 유전체 (genome) 또한 두개의 small noncoding RNA인 CsrB와 CsrC homologue를 갖고 있으며 이들의 varA 돌연변이에 의해 억제되는 것으로 나타났다. 이상의 결과는 패혈증 비브리오균의 새로운 신호전달 시스템인 VarS/VarA/CsrB/C/CsrA가 독력조절에 중요한 역할을 하고 있음을 시사한다. Vibrio vulnificus, a halophilic estuarine bacterium, rapidly proliferates in susceptible human hosts and causes tissue necrosis and fatal septicemia. Pathogenic bacteria recognize environmental change and modulate specific gene expression by various two-component signal transduction systems composed of cognitive histidine kinase and response regulator pairs. The VarS/VarA two-component system homologues exist in a variety of gram-negative bacteria: they are BarA/UvrY in Escherichia coli, BarA/SirA in Salmonella typhimurium, and VarS/VarA in Vibrio cholerae. This system was reported to operate a switch between primary and secondary metabolism in response to environmental changes, with a major involvement in posttranscriptional control mechanisms. A number of virulence traits were reported to be under the control of this system in different pathogenic bacteria. We identified VarA homolog and constructed an in-frame deletion mutant of varA gene in a highly virulent V. vulnificus strain. The mutation altered colony morphology from opaque to translucent and caused a growth defect during both late exponential and early stationary phases. Cytotoxicity to eukaryotic cells was significantly decreased by the mutation. Those changes in the mutant could be complemented in trans by a plasmid encoding a wild-type allele of varA. Lethality of the var- mutant to mice was decreased by 10-fold. These results suggest that VarA may play an important role in virulence regulation of V. vulnificus. In other gram-negative bacteria, VarS/VarA homologues were reported to interact with noncoding regulatory RNAs. We identified two small nonconding RNAs, CsrB and CsrC, in the V. vulnificus genome, and found that they were down regulated in the varA deletion mutant. These results imply the existence of a virulence regulation signaling cascade in V. vulnificus: signals should be relayed in the sequence of VarS ' VarA ' CsrB/C ' CsrA ' yet unidentified effectors genes.

A Study on Subjective Assessment of 360-Degree Image Projection Formats

TRAN THI HAI UYEN Sejong University Electronics Engineering 대학원 2019 국내석사

Recently, virtual reality is rapidly spreading in the industrial fields such as games, entertainment, and 360° image and video are widely used in various applications of the virtual reality market. Along with the growing rapidly of 360° image/video market, there are many projection formats which have been published and researched. On the other hand, the studies which figure out the best quality formats for researcher works and commerce are still limited. Therefore, it is needed to have an experiment to verify the quality of those projection formats. This thesis briefly presents ten projection formats which have been proposed by JVET and an experiment for evaluating the quality among those projection formats by using 360Lib and our proposed software. Firstly, a subjective experiment is conducted for ranking ten 360° projection formats quality based on their viewports that generated by 360Lib. The proposed methodology for subjective test uses the combination of Degradation Category Rating and Pair Comparison method. Secondly, we developed our own software which supports displaying four projection formats in virtual reality mode. The subjective test also conducted by using the developed software. Interestingly, both subjective test experimental results have shown that Equi-rectangular (the most famous and used at all most commercial product) was not represented as the best quality format when comparing with the others. In contrast, Hybrid equi-angular cubemap and equatorial cylindrical projection were judged best quality formats when compared with the others. Furthermore, we figure out the different monitors has not affected the ranking of 360° image format quality. Our effort will be useful for the future 360° image standard. 최근 게임 및 엔터테인먼트 산업 분야에서 가상 현실이 급속히 확산되고 있으며 가상 현실 시장의 다양한 응용 분야에서 360° 이미지와 비디오가 널리 사용되고 있다. 빠르게 성장하는 360° 이미지 / 비디오 분야 외에도 많은 프로젝션 형식이 발표되고 연구되고 있으나, 최고의 품질을 제공하는 프로젝션 형식을 찾는 연구는 여전히 제한적이다. 따라서 이러한 프로젝션 형식의 품질을 검증하기 위한 실험이 필요하다. 본 학위 논문에서는 JVET에서 제안한 10 가지의 프로젝션 형식과 360Lib 라이브러리와 제안 된 소프트웨어를 사용하여 프로젝션 형식 간의 품질을 평가를 수행한다. 주관적인 방법으로 품질을 평가하기 위한 방법을 제안하고 평가를 수행한다. 첫째, 주관적인 실험은 360Lib에 의해 생성 된 뷰포트 이미지를 기반으로 하여 10 개의 360° 프로젝션 형식들의 품질을 평가한다. 주관적 테스트를 위해 제안 된 방법론은 DCR (Degradation Category Rating) 방법과 PC (Pair Comparison) 방법의 조합을 사용한다. 둘째, 네 가지 투영 형식을 지원하는 자체 개발된 소프트웨어를 기반으로 주관적인 테스트를 수행하였다. 흥미롭게도, 주관적인 테스트 실험 결과는 상업적인 제품에서 모두 사용되고 있는 가장 유명한 ERP 프로젝션 형식이 다른 형식과 비교할 때 최상의 품질 형식으로 나타나지 않는다는 것을 보여주었다. 대조적으로 HEC (Hybrid equi-angular cubemap)과 ECP (Equatorial cylindrical projection) 방법이 다른 것과 비교했을 때 최상의 품질을 제공하는 형식으로 판단되었다. 또한, 우리는 모니터의 종류가 360° 이미지를 위한 프로젝션 형식의 품질에 영향을 미치지 않음을 확인하였다. 본 학위논문의 연구 결과는 미래의 360° 이미지 표준 개발에 유용 할 것입니다.