Development on hybrid-capacitor with high energy density

Ha, Seong-Ji Graduate School of UNIST 2019 국내석사

In this thesis, I observe the methods to overcome the low energy density in the supercapacitor system which is the crucial issue in energy storage industries. I challenge simple and easy approaches to achieve better capacitor properties than before by fabricating the three-dimensional structure of current collector and colloid structure of active material. First, rational design of the current collector with large surface area and high electrical conductivity is the very important factor in the hybrid-capacitor system for high performance. Nickel particles-coated three-dimensional graphene foam current collector (Ni-GF) was fabricated by two simple steps from cost-effective commercial cotton and nickel chloride, based on the growth of graphene on the surface of nickel particles. The welded nickel particles on graphene sheets and three-dimensional graphene networks enhance the electrical conductivity and various pores in graphitic carbon domains gives the high surface area, generated by the thermal decomposition of organic precursors during a carbonization or pyrolysis process. This strategy provides the high performance in the supercapacitor system as the current collector. The high surface area of Ni-GF supports a lot of reaction sites of active materials and high electrical conductivity helps the good rate capability and long-term cycle life. The prepared Ni(OH)2/Ni-GF//MnO2/Ni-GF capacitor exhibited an excellent energy density of 175 Wh kg-1 at a power density of 722 W kg-1 for a two-electrode system. Also, I improve the weakness of supercapacitors such as low energy density by utilizing cobalt and nickel ion colloidal electrodes on a carbonized cotton. Ni2+ and Co2+-coated carbonized cotton (NC/CC) were prepared by simple and rapid fabrication process. The metal colloidal electrode on three-dimensional carbon foam provides many active sites, which leads to a lot of redox reactions in whole colloids of CNFs. CNFs were optimized by adjusting the contents of Co2+ and Ni2+ on carbon foams, and it showed high capacitance and stable cycle stability. The optimized NC/CC//Mn/CC capacitor leads to overcome a limitation of supercapacitor and to achieve the enhancement of capacitor properties. The outstanding performance of NC/CC//Mn/CC is attributed to the increased active sites of metal colloidal electrodes as well as to the good stability for carbon foams. These excellent electrochemical results have the great potential for energy storage devices with high values of energy density and power density.

Optimizing primary template-directed amplification to find accurate somatic mutations in postmortem tissues

지민지 Graduate School, Yonsei University 2024 국내석사

Somatic mutations, which accumulate during cell division, are crucial for understanding genetic diversity, cellular heterogeneity, and disease mechanisms in the human genome. Primary Template-Directed Amplification (PTA) is an advanced technique for amplifying single-cell DNA, particularly effective for analyzing postmortem tissues with compromised DNA quality. Fibroblasts from multiple anatomical sites of deceased donors were cultured and isolated using fluorescence-activated cell sorting (FACS) and microfluidic cell sorting. PTA was used to amplify DNA from these single cells and small clusters. The amplified DNA was subjected to whole-genome sequencing (WGS) for detailed analysis. Bioinformatics approaches were applied to identify somatic mutations and evaluate the fidelity and coverage of PTA. PTA efficiently amplified DNA from single cells, providing extensive genomic coverage and maintaining sequence integrity. The technique allowed precise somatic mutation detection across the genome. Optimal performance was observed in both single-cell and small-cluster samples, enhancing the accuracy of mutation identification. This study confirms PTA as a robust method for high-fidelity amplification of single-cell DNA from postmortem tissues, facilitating accurate somatic mutation detection. These results significantly contribute to our understanding of genetic diversity and cellular lineage, with important implications for future research in human genetics and personalized medicine. PTA's capacity to minimize amplification artifacts and ensure high genomic coverage establishes it as a vital tool in single-cell genomics. 세포 분열 중에 축적되는 체세포 돌연변이는 인간 게놈의 유전적 다양성, 세포 이질성, 질병 메커니즘을 이해하는 데 매우 중요하다. 1 차 템플릿 지시 증폭 (PTA)은 단일 세포 디옥시리보핵산 (DNA)를 증폭하는 고급 기술로, 특히 DNA 품질이 손상된 사후 조직을 분석하는 데 효과적이다. 사망한 기증자의 여러 해부학적 부위에서 섬유아세포를 배양하고 형광 활성화 세포 분류 (FACS)와 미세 유체 세포 분류를 사용하여 분리했다. PTA 를 사용하여 이러한 단일 세포와 작은 클러스터에서 DNA 를 증폭했다. 상세한 분석을 위해 증폭된 DNA 에 대해 전장 유전체 시퀀싱(WGS)을 진행하였다. 이후 생물정보학적 접근법을 적용하여 체세포 돌연변이를 식별하고 PTA 의 정확성과 커버리지를 평가했다. PTA 는 단일 세포에서 DNA 를 효율적으로 증폭하여 광범위한 게놈 커버리지를 제공하고 시퀀스 무결성을 유지한다는 사실을 확인하였다. 이 기술을 통해 게놈 전체에서 정밀한 체세포 돌연변이 검출이 가능했다. 단일 세포 및 소규모 클러스터 샘플 모두에서 최적의 성능이 관찰되었으나, 조건에 따른 증폭 정도의 비교 분석을 통해 PTA 를 위한 최적의 조건을 성립하였다. 이 연구를 통해 PTA 가 사후 조직에서 단일 세포 DNA 의 효과적인 증폭을 위한 강력한 방법으로서 정확한 체세포 돌연변이 검출을 용이하게 한다는 것을 확인했다. 이러한 결과는 유전적 다양성과 세포 계통에 대한 이해에 크게 기여하며, 향후 인간 유전학 및 개인 맞춤형 의학 연구에 중요한 시사점을 제공한다. 증폭 아티팩트를 최소화하고 높은 게놈 커버리지를 보장하는 PTA 의 능력은 단일 세포 유전체학에서 중요한 도구로 자리매김하고 있다.

An Analysis of the Sources and Influences in the Creation of "Korean Folk Song Suite" by Ji-Soo Hwang

황지수 Univ. of Minnesota 2004 해외박사

새로운 음악을 창조하는 데 있어서 한국과 서양적인 요소의 융합은 많은 한국 작곡가들에게 중요한 요소이다. 황지수 작곡의 "Korean Folk Song Suite"에서 한국 민요가 전통음악의 형태 속에 가지는 구조와 지방마다 다른 성격을 보이며 나타나는 여러 특징들이 서양 음악의 틀에서 어떻게 발현되는지 분석되어있다. 한국 민요의 잠재력이 한국 음악의 정수를 보여주며 이 곡에 미친 영향은 지대하다. 생생한 아이디어와 음악의 고유성은 뚜렷이 구분되는 특징을 통해 새로운 음악의 창조에 갚이 관여하고 있다. "Korean Folk Song Suite"은 헝가리 작곡가인 벨라 바르톡의 "헝가리 농부의 민요에 의한 즉흥곡 Op. 20"의 형식에 영향을 받기도 했다. 새로운 화성과 즉흥적인 음악이 흐름이 그것이다. 그리고 또다른 영향은 황병기의 많은 작곡과 연주라 하겠다. 한국 고유의 음악과 악기로 새로운 지경을 실험적으로 개척하여 새로운 음악을 만들어낸 것이다. "Korean Folk Song Suite" 곡의 분석을 하게 된 기회를 통해 새로운 음악을 창조하는 과정에서 어떻게 서로 다른 음악이 통합되어 나타나는지 배경과 자료들을 밝힌다. 제 1장에서는 역사적 발전과 지리적 구분이 음악에 어떤 영향을 미치며 다른 성격을 보이는지 밝히고, 한국 음악의 여러 특징을 기술하고 있다. 제 2장에서는 각 민요의 역사적 배경의 중요성과 함께 가사 및 음악적 분석을 통해 이 곡에서 어떻게 표현되고 있는지 각 곡의 분석하고 있다.

A Highly Utilizable Web Service Planner with Extended Capabilities : 확장된 기능을 가진 고기능 웹 서비스 플랜너

KIM, JI-HYEON GRADUATE SCHOOL OF CHUNGNAM NATIONAL UNIVERSITY 2005 국내박사

웹 서비스란 네트워크 상에서 컴퓨터간의 상호 운용이 가능한 소프트웨어 시스템이다. 이는 컴퓨터가 인지할 수 있는 형식 (예를 들어 DAML-S, WSDL) 으로 기술되고 이 서비스를 필요로 하는 쪽에서는 SOAP등과 같은 표준 프로토콜을 사용해 미리 기술된 방법에 따라 서비스를 활용하게 된다. 웹 서비스 플랜닝은 사용자의 서비스 요구를 만족시킬 수 있도록 필요한 웹 서비스들을 찾아 조합하는 것이다. 사용자의 서비스 요청을 만족시킬 만한 웹 서비스가 없을 때 웹 서비스 플랜너는 자동으로 가용한 서비스들을 조합해 사용자의 요구를 만족시키도록 플랜닝한다. 사용자의 서비스 요구는 서비스 형태로 표현되며 이는 웹 서비스들과 비교, 매칭을 하게 된다. 웹 서비스 플랜닝의 중요한 관건은 어떻게 하면 사람의 간섭을 최소화시켜 필요한 서비스들을 조합하느냐 하는데 있다. 실제 많은 웹 서비스 플랜너들은 자동으로 플랜 닝을 하고 있다. 그러나 현재까지 알려진 방법들은 몇 가지 문제점들을 갖고 있다. 즉 1) 기존의 서비스 플랜너들은 컨셉트간의 충돌을 고려하고 있지 않다. 만약 두 매칭 서비스간의 컨셉트 충돌이 발생한 경우 충돌된 컨셉트를 갖고 있는 웹 서비스는 플랜닝 패스를 만들 때 선택되어서는 안 된다. 기존의 플랜너들은 이 경우 단지 충돌된 컨셉트간에 내포관계가 없는 것으로만 단정한다. 2) 기존의 플랜너들은 위음성(false-negative) 조건을 고려하지 않는다. 위음성 조건이란 플랜어가 찾은 서비스 집합은 답의 일부만을 찾아낼 수도 있다는 것을 말한다. 주어진 사용자의 요구를 만족시키는 플랜닝 패스는 일반적으로 여러 개가 존재한다. 기존의 서비스 플랜너들은 일단 하나의 서비스 패스가 성공적으로 작성되면 이 찾아진 서비스 패스를 보완해줄 수 있는 다른 서비스 패스를 더 이상 찾지 않는다. 그러나 실제로는 다른 서비스 패스가 존재해서 이미 찾아진 서비스 패스를 보완해줄 수 있는 기회가 있다는 것이다. 3) 기존의 서비스 플랜너들은 백트랙킹 플랜닝을 하지 않는다. 현재까지의 플랜너들은 다소 단순한 출력-입력 파이프라인을 통한 직진 플랜너들이다. 위에 언급된 이러한 문제점들을 해결하기 위하여 이 논문에서는 확장된 플랜닝 메커니즘을 제안하였다. 제안된 플랜너는 다음의 두 액션을 통해 자동화된 서비스 플랜닝을 하게 된다. 첫째, 만약 요청 서비스가 발견된 서비스의 입력 요구사항을 만족 시키지 못할 경우 이 요구 사항을 만족하기 위한 서비스 플랜닝을 한다. 둘째로 만약 찾은 서비스가 요청 서비스의 출력 요구를 부분적으로밖에 만족시킬 수 없는 경우 이 요청 서비스를 만족시키기 위한 서비스 플랜닝을 수행한다. 제안된 플랜닝 메커니즘은 플랜닝 성공 율을 높이기 위해 백트랙킹 플랜닝을 하다. 이 플랜닝 메커니즘은 플랜닝 패스를 만들 때 잘못된 서비스를 선택하는 오류를 피하기 위해 컨셉트 충돌을 검사한다. 또한 제안된 플랜닝은 위음성 조건 발생시 보완 서비스 플랜닝을 수행한다. A Web service is a software system designed to support interoperable machine-tomachine interaction over a network. It has an interface described in a machineprocessable format (e.g., DAML-S, WSDL) and other systems interact with the Web service in a manner prescribed by its description using standard protocols like SOAP. Web service planning is to find an executable sequence of Web services that achieves a given user’s service request. When there is no available service that satisfy the user’s request, the Web Service planner tries to find out a way that can satisfy the request through service planning with available services automatically. User’s requst is expressed as a service that can be compared and matched to Web services. One of the essential problems of Web service planning is how to compose the services together with minimal human effort. There are many Web service planners that do the service planning automatically. Although the service planning is done automatically the current plannings methods still have several problems, i.e., 1) the planners don’t consider the concept conflict. When there is a concept conflict between two matching services, the conflicted provider’s service should not be selected in planning path generation. The known planners just consider the concept conflict as there being no subsumption relationship between the two conflict concepts. 2) the current planning methods don’t consider the false-negative conditions. The false-negative condition means that the found service set may return just a part of answers. There may exist several provider’s service paths that can satisfy the current request. When planning finished with success for the requester’s service request, the known planners no longer consider the complement planning paths that can complement the pre-found service paths. One thing we can notice is that, in some cases, even the planned path can satisfy the request, another planning path can complement the pre-found service sets that can supply the service results that the pre-found service sets can’t supply. 3) the web service planners don’t consider the backtracking planning. To the present, there are relatively simple straight forward planners that do the planning through outputinput pipelining. These methods can limit the planning success rate. To solve the problems mentioned above, we suggested an extended planning mechanism. The service composition method suggested in this dissertation does automatic Web service planning with the following two actions. Firstly, if the request service is not entitled to receive a found service, the planner tries to find the complement services for the request service so that the request service is entitled to get the found service. Secondly, if the request service is partially satisfied by a found service, then the planner tries to find the complement service that can complete the request. The proposed extended planning mechanism entails backtracking to increase the service availability and planning success rate. The planning mechanism also considers the concept conflict to avoid selecting the wrong service in planning path generation. The proposed planner also does complement planning for false-negative condition.

Sestrin2 acts as a negative regulator of inflammasome activation by inducing mitophagy

김민지 Graduate School, Yonsei University 2015 국내박사

In “danger” conditions, such as infections, the NLRP3 inflammasome complex is positively regulated by mitochondria-generated reactive oxygen species and negatively regulated by autophagy. Thus, tight regulation of both mitochondrial integrity and autophagy is essential for proper inflammasome activation. Here, I demonstrate that Sestrin2 suppressed continuous inflammasome activation by preserving mitochondrial homeostasis through inducing selective autophagy. Sestrin2 plays a dual role to remove damaged mitochondria caused by stimulation with LPS and ATP in macrophages. First, Sestrin2 facilitates the perinuclear clustering of damaged mitochondria by mediating aggregation of p62/SQSTM1 and its recruitment to Lys 63 ubiquitins on mitochondria surface. Second, Sestrin2 induces autophagosome formation and mitophagy through maintenance of ULK1 stability. Thus, both Sestrin2- and p62-deficient mice had more damaged mitochondria, and produced more caspase-1-dependent cytokines, including IL-1β and IL-18, and had higher mortality in sepsis models. These findings identify a novel role of Sestrin2 and p62 for protection against incessant inflammation.

Physical and chemical modification of ordered mesoporous carbon materials for CF4 adsorption

Park, Hyeonji Sungkyunkwan University 2023 국내석사

Due to the increase in global energy demand, greenhouse gas concentrations are increasing every year. Among the PFCs, which are widely used in the semiconductor industries and possess extremely high global warming potentials, carbon tetrafluoride (CF4) contributes significantly to the greenhouse effect despite its low atmospheric concentration. In order to prevent CF4 emission, adsorption is considered a potential option because of its relatively low cost and convenience to operate without producing byproducts. Various candidates with large surface area and highly porous structure have been studied for CF4 adsorption, and carbon-based adsorbents are especially promising due to the merits of physical and chemical stability and facile synthesis. In this research, physical and chemical modification of ordered mesoporous carbon (OMC) materials were conducted. The micropore developed OMC with phosphoric acid catalyst and boron oxide doped OMC for addition of Lewis acid sites were synthesized to enhance the CF4 adsorption performance. In order to evaluate the adsorption capacities of the materials, CF4 dynamic adsorption, isotherms, breakthrough experiments were performed. 전 세계 에너지 수요의 증가로 인해 온실가스 농도는 매년 증가하고 있다. 소량으로도 문제를 일으키는 온실가스 중 CF4는 반도체 제조 공정에서 사용되며 안정적인 사면체 구조로 인해 대기 수명이 5만년으로 매우 길다. CF4 배출을 방지하기 위한 방법들 중 흡착은 상대적으로 비용이 저렴하고 부산물을 생성하지 않고 운영이 편리하여 효과적이다. CF4 흡착을 위해 넓은 표면적과 높은 다공성 구조를 가진 다양한 물질들이 연구되어 왔으며, 특히 탄소계 흡착제는 물리적, 화학적 안정성과 합성이 용이하다는 장점 때문에 유망하다. 본 연구에서는 메조기공성 탄소(OMC) 물질의 물리적 및 화학적 변형을 수행하였고, 인산 촉매를 사용한 미세기공이 발달된 OMC와 boron oxide가 도핑된 OMC를 합성하여 기존의 일반적인 OMC에 비해 CF4 흡착 성능을 향상시켰다. 물질의 흡착능을 평가하기 위해 CF4 동적 흡착, 등온선, 파과 실험을 수행하였다.

Quenching effects of selected non-polar phenolic antioxidants on singlet oxygen and their suppressive activities on the photosensitized oxidation of vegetable oils

김지인 Graduate School, Yonsei University 2009 국내박사

It is interesting that molecular oxygen and lipid matrices share a paradoxical phenomenon as they are essential but not may be detrimental to the survival and health of the human species. Foods containing lipids in an oxygen and light-rich environment are prone to be faced upon the potential risk of oxidative processes. The molecular oxygen is an essential ingredient to support life on earth from biological point of view. Roles of the oxygen in foods involve direct or indirect interactions with light. Understanding of the interactions of lipids with oxygen and/or light is important to evaluate functions of conventional antioxidants and to develop novel antioxidants with a broad antioxidative protection. The purpose of this study was to examine the quenching effects of selected non-polar phenolic antioxidants (nPhOH) on singlet oxygen in the organic solvents and linoleic acid of homogeneous system and their suppressive activities on the photosensitized oxidation in the vegetable oils of heterogeneous system. In part I, singlet oxygen quenching effects of selected nPhOH, i.e., tert-butylated hydroxyanisole (BHA), tert-butylated hydroxytoulene (BHT), tert-butylated hydroquinone (TBHQ), and α-tocopherol, on a methylene blue (MB)-sensitized photooxidation of linoleic acid have been studied. The singlet oxygen quenching mechanism was studied using both electron spin resonance (ESR) spectroscopy in a 2,2,6,6-tetramethylpiperidone (TMPD)-MB system and spectroscopic analysis of rubrene oxidation induced by a chemical source (sodium molybdate + hydrogen peroxide) of the singlet oxygen. Total singlet oxygen quenching rate constants (kox-Q + kq) were determined using a steady state kinetic equation. Among the synthetic antioxidants in this study TBHQ showed the highest protective activity on the MB-sensitized photooxidation of linoleic acid, followed by BHA and BHT. TBHQ (1.0 x 10-3 M) exhibited 86.5% and 71.4% inhibition of peroxide and conjugated diene formations, respectively, in linoleic acid photooxidation after 60 min fluorescent illumination. The protective activity of TBHQ on the photosensitized oxidation of linoleic acid system was almost comparable to that of α-tocopherol (88.8% to peroxides and 73.9% to conjugated dienes). The data obtained from 2,2,6,6-tetramethyl-4-piperidone-N-oxyl (TAN) formation in ESR and rubrene oxidation studies clearly showed the strong singlet oxygen quenching ability of TBHQ as 81.6% and 74.8%, respectively. These data were as compared with those of α-tocopherol (77.7% to TAN formation and 82.0% to rubrene oxidation). The (kox-Q + kq) of BHA, BHT, and TBHQ were 3.37 x 107, 4.26 x 106 and 1.67 x 108 M-1sec-1, respectively. The (kox-Q + kq) of TBHQ was within the same order of magnitude of that of α-tocopherol (3.54 x 108 M-1sec-1), an efficient singlet oxygen quencher. There was a high correlation (r2 = 0.991) between logarithmic value of (kox-Q + kq) and reported the ionization potentials for BHA, BHT, and TBHQ, showing their charge-transfer mechanism for singlet oxygen quenching. This is the first report on the kinetic study on the (kox-Q + kq) of TBHQ in methanol as compared with other commonly used commercial synthetic antioxidants and α -tocopherol. In Part II, the stoichiomtric correlation between free radical scavenging activities and singlet oxygen quenching activities of nPhOH was investigated. To compare with the singlet oxygen quenching activities determined in Part I, antiradical activities of nPhOH have been estimated using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH?) bleaching assay. The DPPH? bleaching assay showed linear dose-responses in the range of 0 to 0.27 [nPhOH]/[DPPH?] molar ratio. Different parameters such as radical scavenging capacity (RSC, %), 50% inhibition concentration (IC50), remaining [DPPH?], 50% efficient concentration (EC50), time taken to scavenging 50% of the initial [DPPH?] (T50%30uM/min), and antiradical efficiency (AE) were measured within the 0 to 0.27 of [nPhOH]/[DPPH?] molar ratio. Reaction stoichiometries such as antiradical power (ARP), stoichiometric value (SV), and n value were calculated for mechanistic speculation on structure-activity relationship. The DPPH? bleaching assay showed that RSC at [nPhOH = 8 μM] was in the order of TBHQ (79.4%) > α-tocopherol (71.3%) > BHA (56.9%) > BHT (41.7%). The nPhOH showed the same decreasing orders with the RSC data in the IC50, EC50, T50%30uM/min and SV, while they showed the same increasing orders in the AE, ARP, and n value. It was interesting to speculate that the strongest antiradical effectiveness of TBHQ was resulted from its specific structure-activity relationship. Particularly, the n value calculated based on EC50 confirmed the implication of more than one step in the reaction of nPhOH with the DPPH?. In the n value, TBHQ also exhibited the highest level (n = 2.96), followed by α-tocopherol (n = 2.63), BHA (n = 2.25), and BHT (n = 1.53). The n values of nPhOH, except the α-tocopherol which is structurally different, showed significantly higher correlations with their logarithmic value of (kox-Q + kq) given in Part I of the present study. This result indicates a close relationship between the antioxidative activities of nPhOH for both singlet oxygen quenching and free radical scavenging, suggesting their synergistic actions via charge-transfer and/or hydrogen-donation. In Part III, the inhibitory effects of the selected nPhOH on the photosensitized oxidation of commercial vegetable oils (soybean oil, corn oil, and canola oil) under fluorescent light at room condition were investigated. The inhibitory effects of nPhOH to the formation of primary oxidation products, secondary oxidation products, and sensory impact compounds in the system have been evaluated by monitoring peroxide value (POV), total volatile compounds in headspace (TVC), and C3-aldehydes by solid phase microextraction (SPME)/GC-MS analysis. POV (an indicator of primary oxidation) at day 0, 1, 2, 3, 4, and 5 were 2.8, 11.7, 19.26, 28.4, 33.3, and 45.9 meqO2/kg oil for the soybean oil; 0.6, 5.8, 9.8, 18.4, 20.5, and 24.4 meqO2/kg oil for the canola oil; and 1.3, 5.5, 10.8, 16.9, 19.8, and 21.8 meqO2/kg oil for the corn oil, respectively. TVC (an indicator of secondary oxidation) at day 0, 3, and 5 were 112.5 x 104, 374.2 x 104, and 601.3 x 104 mVsec for the soybean oil; 6.9x104, 179.0 x 104, 287.5 x 104 mVsec for the canola oil; and 6.9 x 104, 179.0 x 104, and 287.5 x 104 mVsec for the corn oil, respectively. C3-aldehydes (an indicators of sensory impact) at day 0, 3, and 5 were 14.7 x 104, 68.0 x 104, and 61.5 x 104 mVsec for the soybean oil; ~ 0.0 x 104, 30.5 x 104, and 51.2 x 104 mVsec for the canola oil; and 12.0 x 104, 26.3 x 104, 58.9 x 104 mVsec for the corn oil, respectively. These oxidation markers showed that the photosensitized oxidation of vegetable oils increased significantly as the fluorescent light exposure time increased (P < 0.05). A possible mechanism of light-induced oxidation was speculated as singlet oxygen-mediated photosensitized oxidation via excitation of chlorophyll species under fluorescent light in the presence of ordinary oxygen. The regression analysis of data obtained from the photosensitized oxidation of the vegetable oils revealed a high correlation (r2 = 0.995 for soybean oil, 0.978 for canola oil, and 0.914 for corn oil, respectively) between POV and TVC, suggesting that TVC can also be used as a reliable indicator to measure the antioxidant activities. At 200 ppm, TBHQ showed the highest decrease (22.7%) in the POV, followed by BHT (11.2%), BHA (5.1%), and α-tocopherol (-5.9%). As expected but it was interesting that α-tocopherol promoted the formation of hydroperoxides in the photosensitized oxidation of vegetable oils. TBHQ exhibited the highest decrease (57.7%) in the TVC, followed by α-tocopherol (30.5%), BHT (24.7%), and BHA (13.2%). TBHQ also showed the highest decrease (80.5%) in the development of C3-aldehydes, followed by α-tocopherol (34.0%), BHT (24.8%), and BHA (14.5%). Contrary to the inhibitory effect on the basis of POV, the addition of nPhOH significantly inhibited the development of TVC and C3-aldehydes in the vegetable oils (P < 0.05). The data showed that the TBHQ treatment contributed to retard the photosensitized oxidation of vegetable oils in the order of sensory impact (80.5%) > secondary oxidation (57.7%) > primary oxidation (22.7%). The high antioxidant activity of TBHQ in homogeneous system such as the organic solvents and linoleic acid and in heterogeneous system such as the vegetable oils can be explained as the combined effects of free radical species scavenging by hydrogen donation, singlet oxygen quenching by partial charge-transfer, and a deactivation of triplet excited chlorophyll species. In aspect oriented multifunctional antioxidative activity of TBHQ, which have been observed in Part I, II, and III of the present study, it is expected that TBHQ under regulation could be economically and broadly applied to medical, food, cosmetic, and polymer industries to effectively prevent the singlet oxygen-mediated photosensitized oxidation and/or triplet oxygen-mediated free radical autooxidation of various biological compounds such as unsaturated lipids, oil-soluble vitamins and other oil-soluble components including cholesterol, limonene, conjugated terpernes, and photodegradation of industrial materials like polymers.

Valuation Method and Investment Advantages of Foreign Bonds

장은지 부산대학교 대학원 2019 국내석사

While investing in foreign bonds may be considered a risky investment, you can expect a steady return if you set a good strategy. With the steady increase in investment in foreign bonds these days, this report examined the valuation methods, concepts and investment advantages of foreign bonds. The valuation method is divided into fixed and variable interest rates. The advantage of investing in foreign bonds is that you can benefit from high interest rates and tax benefits. However, in order to make a good investment, it is necessary to consider various circumstances before investing. 저금리, 저물가, 저성장 시대에 더 나은 투자전략을 찾기란 어려운 일이다. 본 리포트에서는 해외채권의 평가방법과 투자의 이점 및 주의사항을 살펴보고자 한다. 해외채권 평가 시 고정금리와 변동금리로 나누어서 평가하며 평가원칙을 준수하여 평가해야 한다. 해외채권은 국내채권보다 금리가 더 높고 절세 혜택이 있다는 것이 가장 큰 장점이지만 금리가 높다 해서 무조건 투자하는 것이 아니라 각국의 이슈를 확인하고 다양한 변동성에 대응하며 개인적인 목적에 적합한 채권에 투자해야 한다. 환율변동에 주의해야 하며 특히 신흥국 국채는 환율 변동성이 매우 크므로 더욱 주의해야 한다. 경제, 정치적 요인 이외에 신용리스크 에도 주의를 기울여야 하는데 시장금리 변동 보다 신용 리스크가 채권 가격 변동에 더 큰 영향을 미치기 때문이다. 따라서 해외채권에 바람직하게 투자하기 위해서는 여러 가지 상황들을 고려한 후 투자해야 할 필요가 있다.

(The) effects of electrical stimulation of the nucleus basalis magnocellularis/the reuniens thalamic nucleus on memory function in a rat model of dementia

이지은 Graduate School, Yonsei University 2013 국내석사

Deep brain stimulation has been used to treat various neurological disorders. Recently, some studies suggest that deep brain stimulation can treat Alzheimer’s disease. Memory deficits associated with a reduction in cholinergic projections in the cortex and hippocampus are the one of the characteristics of Alzheimer’s disease. This study was designed to determine the effect of electrical stimulation of the nucleus basalis magnocellularis or the reuniens thalamic nucleus on spatial memory using a rat model mimicking the basal forebrain cholinergic deficits of Alzheimer’s disease. We damaged basal forebrain cholinergic neurons using 192 IgG-saporin. Rats in the stimulation group received stimulation of the nucleus basalis magnocellularis and the reuniens thalamic nucleus daily beginning one week after surgery until the start of behavioral testing. The Morris water maze and the object in place were used to evaluate visuo-spatial and visuo-working memory 2 weeks after surgery. Choline acetyltransferase immunohistochemistry was performed to examine 192 igG-saporin-induced cholinergic lesions in the medial septum, and acetylcholinesterase assay was used to evaluate acetylcholinesterase activity in the medial prefrontal cortex and hippocampus. Also, we used western blot analysis to examine changes in GABAergic and glutamatergic systems. The stimulation group of the nucleus basalis magnocellularis showed excellent performance in the probe trial of the Morris water maze task. In the stimulation group of the nucleus basalis magnocellularis, the reduction of the glutamate and glutamic acid decarboxylase was induced in the medial prefrontal cortex. The stimulation group of the reuniens thalamic nucleus showed slightly higher performance in the object in place task. In the stimulation group of the reuniens thalamic nucleus, the reduction of the glutamate in the medial prefrontal cortex and glutamic acid decarboxylase in the hippocampus was induced. Also, the acetylcholinesterase activity was significantly increased as compared to the implantation group of the reuniens thalamic nucleus. The present study demonstrates that stimulation of the nucleus basalis magnocellularis appears to predominately facilitate visuo-spatial memory, whereas stimulation of the reuniens thalamic nucleus appears to predominately facilitate visuo-working memory.

Nanoporous carbon-coated zeolite for advanced adsorption of NH3 and iso-propyl alcohol under humidity conditions

Moon, Hyeonji Sungkyunkwan University 2022 국내석사

As semiconductor industries become more integrated along with technological developments, the environmental technologies to control air purity with ultra-low concentration of ppt level beyond the ppm and ppb have been required. Therefore, it is necessary to develop an advanced adsorbent from the viewpoint of the semiconductor fabrications. Moreover, the development of selective adsorbent for target molecules is critical because there are various kinds of gaseous molecules. One of the practical issues is the presence of water vapors in the semiconductor process, which may reduce the removal capacity due to the competitive adsorption between the target gas and water molecules. In this study, a commercially available Y-type zeolite, USY-30 (SiO2/Al2O3 = 30), was chosen as a candidate for the removal of NH3 and iso-propyl alcohol (IPA) through the dynamic adsorption experiment. In order to improve the simultaneous removal capacities of NH3 and IPA under high humidity conditions (RH 70%), a nanoporous carbonaceous material was coated on the surface of USY-30 zeolite, using sucrose as the carbon sources and p-toluene sulfonic acid as the carbonization catalysts. The carbonization temperature and the amount of carbon precursor were varied to control the surface hydrophobicity as well as microporosity of the carbon shells. As the carbonization temperature increased, the hydrophobicity of the surface increased. Accordingly, the adsorption capacity of IPA increased more than twice that of the pristine USY-30 zeolite. In addition, differences in NH3 adsorption capacity were also observed according to the carbonization temperatures. 기술 발전에 따라 반도체 산업의 집적화, 자동화가 가속되어 가면서 경제적 손실 방지와 더불어 안전한 사업장을 조성하기 위해서는 ppm, ppb의 농도를 넘어 ppt 정도의 극 저농도의 공기 제어 기술이 요구되고 있습니다. 현재 반도체 공정에서 직면한 문제 중 하나는 CMP 공정이나 Wet etching 공정과 같이 공정에 수증기가 함께 존재한다는 것인데, 이는 흡착질 분자와 물 분자 사이의 경쟁 흡착으로 인하여 흡착제의 효율을 크게 감소시킵니다. 따라서 반도체 제조공정에는 고습도 조건에서 기존 흡착제보다 흡착질에 대한 높은 선택성을 지닌 더 발전된 흡착제의 개발이 필요합니다. 본 연구에서는 상용화되어 있는 제올라이트들의 NH3와 iso-propyl alcohol (IPA) 흡착 실험을 통하여 USY-30 제올라이트를 선정하였으며, 고습도 조건(RH 70%)에서의 NH3와 IPA의 동시 흡착 성능 향상을 위하여 탄소 전구체로 sucrose를, 탄화 촉매로 p-toluene sulfonic acid를 사용하여 나노다공성 탄소물질을 USY-30 제올라이트 표면에 코팅하였습니다. 탄소 껍질의 소수성 및 미세 기공도(microporosity) 제어를 위하여 탄화 온도와 탄소 전구체의 양이 조절되었으며. 탄화 온도가 증가함에 따라 표면의 소수성이 증가하였습니다. 소수성 코팅을 통하여 IPA에 대한 선택적 흡착능력이 향상되어, 기존 USY-30 제올라이트에 비하여 2배 이상의 흡착 효율을 보여주었습니다. 또한 탄화 온도에 따라 NH3 흡착 용량의 차이도 관찰되었습니다.