CO₂ absorption and regeneration performance enhancement by nanoabsorbents in combined cycle

이재원 Korea University 2017 국내박사

This study attempted to develop new absorbents with enhanced CO2 absorption/regeneration performance by adding nanoparticles to methanol that is used as the absorbent in the Rectisol process, a physical absorption system. The nanoparticles used for the experiments were SiO2 and Al2O3, and their concentration was set as 0.005, 0.01, 0.05, and 0.1 vol%. The dispersion stability of the fabricated nanoabsorbents was evaluated by measuring particle size, turbidity, and zeta potential of the absorbent. The CO2 mass transfer performance of the nanoabsorbents was analyzed by conducting a combined CO2 absorption/regeneration experiment. The experimental results showed that the optimal concentration of the added nanoparticles was 0.01 vol%, and the addition of SiO2 improved CO2 capture by 22%. However, when Al¬2O3 was added, the performance deteriorated. In addition, a literature review was conducted and a high speed camera and related optical techniques were used to analyze the mass transfer enhancement mechanism in nanoabsorbents in order to identify an optimal mechanism. I found that the most effective models for the mass transfer enhancement mechanism were the hydrodynamic effect for the absorption process and the surface effect for the regeneration process.

Inhibition of cholesterol absorption on human enterocyte by the defatted soluble soy proteins : 지방을 제거한 수용성 콩 단백질의 콜레스테롤 흡수 저해 효과

염유진 경북대학교 대학원 2015 국내석사

Many studies have shown that some substances in soy, such as digested peptides or isoflavones from soy have effects on satiety control and nutrient absorption functions. It has been known that soy bean diet can reduce the blood cholesterol level by interfering the absorption in the small intestine. However, it is still clearly not known how soy can control those functions. We have shown that some of the soluble soy proteins were resistant to proteases, such as pepsin and pancreatin, in the in vitro digestion analysis. Thus, we hypothesized that the protease resistant soy proteins could affect cholesterol absorption in the small intestine either by physical adsorption of cholesterol or direct inhibition of the absorption. To test our hypothesis, an intestinal cell line, Caco-2, was incubated with cholesterol in the presence or absence of soy protein/soy protein digest. The absorption level of cholesterol in the cells was reduced in the presence of soy proteins or soy protein digests when it was analyzed by cholesterol assay. The result suggests that soy protein or its digest can inhibit the absorption of cholesterol by interfering the transport system on the plasma membrane directly or indirectly. Phosphoproteomic changes in the intestinal cell line upon soy protein treatment were tested. After the soy protein treatment, phosphoproteins enriched from the cell extract by IMAC column were separated on 2 D gels and compared for the up and down regulations. Interestingly, many of the proteins involved in protein folding or energy metabolism were significantly phosphorylated by soy protein treatment to the cell line. For further studies, detailed cell signaling pathway/mechanism by soy proteins treatment to the cells are under investigation in view of revealing the function of soy proteins in satiety, nutrient absorption, and others.

Photophysical study of luminescent compounds using time resolved spectroscopic techniques

양일승 서울대학교 대학원 2012 국내박사

Luminescent compounds have drawn significant amount of interest due to its wide applicability and versatile functionality. Many studies have been reported about its chemical properties and applications as fluorescent probes, optoelectronic devices and even as medicinal compounds. Time-resolved spectroscopic technique has its own distinct advantage which enables us to study transient species including excited states, intermediates and transition state. Photophysical and chemical studies are very important to fully exploit the properties of luminescent compounds. In this study, time resolved spectroscopic techniques are fully employed to study and understand excited state dynamics and their novel chemical properties. We developed time resolved spectroscopic techniques such as femtosecond transient absorption spectroscopy and time correlated single photon counting to study the photophysics of luminescent compound. To demonstrate the feasibility of these techniques, we started to study about photophysics of small molecules such as acetone. Photodissociation dynamics of acetone in gas phase were, for the first time, investigated using the pump-probe technique of femtosecond transient absorption. To obtain a genuine time profile of nR state, we employed 200 nm and 400 nm pulses for 2-photon and 3-photon excitation, respectively. In gas phase of acetone, the extraordinarily stable nR state originated from nR state in the Franck-Condon region, whose decay time constant was 350 ± 10 fs, was observed after excitation by 3-photon absorption of 400 nm pulses. In the low power case of 267 nm, the photodissociation dynamics in the S1 state by 1-photon absorption showed that acetone was completely dissociated into two methyl radicals and C=O via an acetyl radical intermediate with a lifetime of 200 ± 10 fs. In the high power case of 267 nm light, we interpreted the transient, although this is a subject of ongoing debate, as caused by both the photodissociation dynamics of the S1 state for a fast component and the dynamics of nR states for long-lived species. The photodissociation dynamics of acetone in liquid phase were investigated using the pump-probe technique of femtosecond transient absorption. In order to obtain the genuine time profile of the nR state (9.3 eV), 3-photon absorption of 400 nm pulses was used. It was found that the nR state was decayed with a time constant of ~100 fs. Acetone in the S1 state after 1-photon absorption of a 267 nm pulse was subsequently dissociated into acetyl radical with a delay time of ~600 fs, after which it relaxed rapidly to the vibrational ground state in the liquid phase. In the high-power case of 267 nm pulses, we assigned two components of the transient, which consisted of a fast component and long-lived species, to the formation of solvated electron in the surrounding cavity after the photo ionization of acetone (fast component) and the formation of a stable acetyl radical after dissociation of acetone (long-lived species). Direct comparison of the dynamics of acetone photodissociation in the liquid phase and those in the gas phase was carried out to understand the effect of solvents on this process. Curcumin is a natural product with antioxidant, anti-inflammatory, antiviral and antifungal functions. As it is known that the excited state intramolecular hydrogen transfer of curcumin are related to its medicinal antioxidant mechanism, we investigated its excited state dynamics by using femtosecond transient absorption spectroscopy in an effort to understand the molecule’s therapeutic effect in terms of its photophysics and photochemistry. We found that stronger intermolecular hydrogen bonding with solvents weakens the intramolecular hydrogen bonding and decelerates the dynamical process of the enolic hydrogen. Exceptions are found in methanol and ethylene glycol due to their nature as simultaneous hydrogen bonding donor-acceptor and high viscosity solvent, respectively. We have investigated the carrier relaxation dynamics of pristine graphene in aqueous solution using femtosecond TA pump-probe technique. Applying aromatic amphiphile exfoliation method, we can obtain genuine temporal information of graphene, free from oxidation. A correlation between the oxidation ratio of graphene and the lifetime of its transients is of much importance due to its practical applications. We adopted time resolved spectroscopic techniques to various applications of luminescent compounds. Meanwhile, we discovered a new fluorescent compound and investigated its physical and chemical properties. A novel phenomenon that might be termed as photochemiluminescence due to the intense luminescence emission from a photochemical reaction product of an originally non-emitting compound is reported along with the chemical identity of the compound itself that has remained elusive to date. We found that UV irradiation of resveratrol leads to its photochemical transformation to highly fluorescent (E)-4-(6,8-dihydroxynaphthalen-2-yl)but-3-en-2-one by using various spectroscopic techniques. This new compound may find wide-ranging applications as an ideal fluorophore in biological imaging because of its high fluorescence quantum yield, large Stokes’ shift, and large two-photon absorption cross section. Water-based photosynthetic systems have attracted a significant amount of interest in the past several decades due to its ability to convert incident sunlight into electrical power in an environment-friendly way. As a model system, we employed the assembly of a phenylenevinylene-based conjugated oligoelectrolyte, 4,4’-bis(4’-(N,N-bis(6’’-(N,N,N- trimethylammonium)hexyl)amino)-styryl)stilbene tetraiodide (DSSN+) as a donor and Nile red as an acceptor that were intercalated into a vesicle of phospholipid membranes. Using transient absorption, we investigated the energy transfer dynamics from DSSN+ to Nile red following the photoexcitation at various intercalation ratios between the donor and acceptor. We also studied the photocurrent generation in an optimized solar cell system. Quantum dots (QDs) are spherically shaped semiconductor crystalline particles with a dimension comparable with or smaller than the exciton size in the respective bulk semiconductor. Due to their novelties such as size dependent optical properties, narrow emission range, and longer fluorescence lifetime, it has been a topic of intensive research in the past few decades. Photophysical properties of QDs and its application were investigated by using time resolved spectroscopy and other various spectroscopic techniques. We investigated the photodyamics of highly stable and luminescent InP/GaP/ZnS QDs. Passivation of QDs such as InP is reported to increase the quantum efficiency and stabilize its structure by protecting the core from external environments. We investigated the charge transfer dynamics of InP QDs passivated with GaP and ZnS shell by using time-correlated single photon counting spectroscopy. 시분해 분광법을 기반으로 하는 광동력학 연구는 분자의 광물리적 특성규명하는데 필수적이다. 이 논문은 시분해 분광법을 이용하여 다양한 발광 화합물에 대한 광물리적 특성에 대해서 연구한 내용을 담고 있다. 주로 펨토초 순간 흡수분광법과 시간 상관 단일 광자 계수법을 이용하여 빛으로 유도된 순간 생성물의 전자상태에 대한 연구를 수행하였다. 펨토초 순간 흡수분광법을 이용하여 기체상 및 액체상에서의 아세톤 광분해에대한 연구를 수행하였다. 아세톤의 이광자 흡수로 인한 리드버그 상태의 정보를 선택적으로 얻을 수 있었으며, 이를 바탕으로 아세톤 광분해 과정에 대한 새로운 정보 해석할 수 있었다. 또한 액체상에서의 아세톤 광분해 연구를 통해서 기체상과 액체상에서의 광분해 현상을 비교 및 분석하였다. 또한 천연 색소이면서 다양한 약리효과를 지니고 있는 curcumin 분자의 들뜬 상태 동력학에 대해 연구하였다. Curcumin 분자와 주변 용액과의 상호작용과 들뜬 상태에서의 수소 전이와의 상관관계에 대한 연구를 transient absorption 기술을 이용하여 분석하였고, 결과에 맞는 모델을 제시하였다. 시분해 분광법의 응용연구로서 여러 발광 화합물에 대한 물리적 특성을 규명하였다. 물 기반의 태양전지의 구현을 위해 DSSN+ 와 Nile red 라는 두가지의 다른 파장영역의 빛을 흡수 할 수 있는 색소를 이중 리피드층에 집적하였다. 이후 DSSN+ 에서 Nile red로의 에너지 전이를 시분해 분광법으로 확인하였고, 이를 기반으로 최적화된 photo current 발생 구조를 제안하였다. 아울러 시분해 분광학을 이용한 연구 과정에서“레스베라트롤”이라는 분자로부터 지금까지 정확하게 알려지지 않은 새로운 고효율의 발광 화합물이 생성되는 것을 발견하였다. 레스베라트롤 용액에 자외선을 조사하여 광화학적 방법으로 형광 물질이 생성되는 과정을 설명하였다.“레스베라트론”이라고 명명된 이 화합물에 대해서 다양한 분광학적 기술을 이용하여 정확한 구조를 규명하였고, 이의 물리화학적 특성에 대한 연구를 수행하였다. 또한 발광화합물로서 넓은 응용성을 가지고 있는 양자점에 대해서, 시분해 분광학을 이용한 광동력학에 대한 연구를 수행하였다.

Structural Approach for Light Absorption Enhancement in Organic Photovoltaics

김강민 연세대학교 대학원 2014 국내박사

Organic photovoltaics (OPVs) have received tremendous interest as next generation renewable energy because of their possibility of solution based low-cost manufacturing with lightweight and flexible devices. However, OPVs suffer from low efficiency, prompting most research efforts to focus on improvement of power conversion efficiency (PCE). The PCE of OPVs depends primarily on three parameters: i) a thick active layer for sufficient photon absorption, ii) large interfaces between donor and acceptor materials for efficient exciton separation, and iii) thin, high-mobility materials and morphological considerations for efficient electron/hole transports. It has been challenging to satisfy all three requirements simultaneously, since the three requirements partially conflict with one another.This dissertation focuses on schemes of enhancing light absorption in active layer without changing morphology and active layer material of OPVs.The inter-diffused ordered bulk heterojunction (IDOBHJ) structure is suggested to satisfy sufficient light absorption, exciton diffusion, and charge collection. This morphology hybridizes advantages of both DBHJ and OBHJ: electric field enhancement in donor material with nano-pillar structure, high exciton dissociation efficiency, and high charge transport efficiency. Based on theoretical analysis, we show experimental demonstration of IDOBHJ. To fabricate IDOBHJ structure, we first made OBHJ structure which has 80nm diameter of P3HT pillar, using nanoimprint lithography. The inter-diffused width was controlled with post annealing (PA) time. The enhancement of absorbance indicates that smaller pillar structures which can enhance electric field at interface of donor material are formed with PA time. The external quantum efficiencies (EQEs) of various PA time suggest there is an optimum PA time for formation of optimized IDOBHJ. The power conversion efficiencies of IDOBHJ show that there exist optimum morphologies with nano-pillars. To enhance the light path in active layer, we describe a simple method employing embedded non-absorbing ZnO nanoparticles in organic photovoltaics. The energy bandgap of ZnO is about 3.3eV, so it makes interference effect of light rather than absorbs it. We demonstrate that embedment of ZnO nanoparticles (20nm diameter) in bilayer OPVs can increase the light absorption in the active layer with experimental and simulational data. Photon absorption was enhanced, a rise leading to an increase in the short circuit current density. The nanoparticles make enhanced electric field in active layer, resulting in enhanced photon absorption. We have demonstrated that the active layer thickness of bulk heterojunction solar cells can be reduced by embedding ZnO nanoparticles. Using embedding nanoparticle, we can reduce the thickness of bulk heterojunction solar cells by nearly half the thickness of conventional device while retaining comparable power conversion efficiency.In addition, we describe a method of generating additional light source for OPVs. We propose incorporating light emitting dyes in OPVs as a route of enhancing light absorption; dyes absorb light in spectrum in which an active layer is transparent and re-emit light in spectrum corresponding to absorption peak of the active layer. Moreover, dyes scatter incoming collimated light isotropically, and this scattering increases light traveling distance in the active layer for enhancing light absorption. The Coumarin 102 (C102) dye has absorption wavelength at 389nm that is the weakest absorption region of P3HT:PCBM blends and then re-emits visible light isotropically into active layer which corresponds to absorption spectrum of the P3HT. Based on these light-absorption-mechanisms, EQE was enhanced both in the near ultra-violet and visible light regions. Finally, the short circuit density of the 2mg of C102 in OPVs which exhibited the best power conversion efficiency was enhanced 28% greater than that of a reference sample without dyes.

Modeling and characterization of thermoplasmonic effects through development of imaging and tip-based measurement

임성민 Graduate School, Yonsei University 2024 국내박사

플라스모닉스는 물리학, 생물학 및 화학 분야를 아우르는 다양한 응용 연구를 위한 기반 기술로서 광자와 자유 전자 간의 상호작용을 통해 금속 표면 근처에서 생성되는 강력한 전자기장을 활용한다. 이 전자기장을 금속 표면 주변에 집중시키기 위해서는 빛 흡수 메커니즘을 이해하는 것이 중요하다. 빛 흡수는 입사광의 에너지를 자유전자로 전달하여, 표면 전자기장을 형성함과 동시에 불가피하게 금속 내에서 열 에너지를 생성하는 것을 포함한다. 흥미롭게도, 플라스모닉스 내에서 열 효과는 많은 연구자들에 의해 과소평가되거나 무시되어왔다. 2010년 초반 이후, 플라스모닉 나노 구조 상에서 발생하는 열을 시각화하고 체계적으로 제어하기 위한 연구들이 진행되어 왔다. 그러나 온도에 의해 발생하는 플라스모닉스 비선형성을 둘러싼 복잡성이 남아 있으며, 적절한 측정 방법의 부재로 인해 빛 흡수와 근접장 강화를 동시에 정량화하는 것은 해결해야 할 문제로 남아 있다. 따라서 본 논문은 플라스모닉스의 중요한 측면인 빛 흡수와 근거리장 강화의 미묘한 상호 작용을 조사하기 위해 개발된 열-플라스모닉 시스템을 통해 이 문제들을 해결한다. 제2장에서는 플라스모닉스에서 발생하는 열의 영향을 정량화하는 방법을 소개한다. 온도 의존 드루드 로렌츠 모델 (Temperature-dependent Drude-Lorentz model)을 활용하고 회귀 광열 분석 방법을 도입하였다. 이를 활용하여 와이어 그리드 편광기 (Wire-grid polarizer)에서의 광열 효과를 조사하였다. 일반적인 상식과는 달리, 본 연구 결과는 와이어 그리드의 채움 계수가 커져, 얇은 필름에 가까워질 때 TM 편광에서 빛 흡수가 더 효과적으로 일어나고 열 생성이 증가함을 밝혀냈다. 또한 편광과 무관하며 구조적 특성에만 의존하는 열 소산 시간을 분석하였다. 더불어, 플라스모닉 이합체 기반 형광 상관 분석 실험에서 발열에 의한 대류가 생체 분자의 움직임에 어떠한 영향을 미치는지 평가하기 위해 광열 및 유체 계산을 수행하였다. 해당 결과로 실험 조건 하에서 온도 상승 및 대류 유속이 생체 분자 및 형광 입자의 움직임을 분석할 때 무시될 수 있음을 밝혀내었다. 마지막으로, 형광 방출체의 방사 및 비방사 감쇄와 금속 나노 홀 간의 거리에 대한 상관 관계를 계산 및 형광 수명 영상법을 통해 조사하였다. 제3장에서는 각도 분해 기반 근접장 주사 광학 현미경을 활용하여 빛 흡수와 근접장 강화를 동시에 측정하는 혁신적인 접근법을 제안한다. 근접장 주사 광학 현미경 팁의 축 이동은 열팽창 (즉, 빛 흡수)을 반영하며, 광전 증폭관 신호는 근접장 주사 광학 현미경 팁 끝의 어퍼쳐 (Aperture)와 커플링 (Coupling) 된 근접장 만을 획득한다. 이러한 결과는 온도 의존 광학 특성을 기반으로 한 회귀 광열 분석을 통해 검증되었다. 본 연구 결과는 금 박막이 비선형 광열 효과로 인해 근접장이 항상 서브선형 (Sub-linear)을 보이고, 빛 흡수는 공명조건에 따라 슈퍼선형 (Superlinear)과 서브선형 모두 보이는 것을 실험적으로 규명하였고, 이는 플라스몬의 조화 감쇠 진동 모델과 회귀 광열 분석을 통해 검증되었다. 본 기술은 삼차원 나노 디스크 배열의 각기 다른 6 곳에서 빛 흡수와 근접장 강화를 동시에 측정함으로써 정확도와 감도가 실험적으로 검증되었다. 제4장에서는 2차원 위상 격자를 활용한 4파 층밀림 간섭계 (Quadri-wave lateral shearing interferometry)와 플라스모닉 나노 구조 상에 발열을 제어하기 위한 여기광이 결합된 열-플라스모닉 자극 및 이미징시스템을 소개한다. 광경로 차이에서 온도를 추출하기 위한 수학적 기술 및 방법론을 설명하면서 해당 기술의 한계를 다루고 해결책을 제안하였다. 열-플라스모닉 자극 및 이미징 시스템을 활용하여 금 나노 격자, 나노 막대, 박막 등 다양한 나노 구조의 광열 응답을 조사하였다. 더불어 호열균의 열 감지 메커니즘을 탐구할 수 있는 편광 감지형 플라스모닉 발열체를 설계하고, 이를 영상화 하였다. 이는 마이크로 스케일에서 열 분포를 자유롭게 조절할 수 있도록 하므로, 여러 생체 시료들의 광열 반응을 획득하는데 효과적일 것으로 기대된다. Plasmonics represents a fundamental technology with multifaceted applications spanning the domains of physics, biology, and chemistry. It leverages the strong electromagnetic fields generated proximate to metal surfaces through the interaction between incident photons and free electrons. To achieve the concentration of this electromagnetic field near the metal surface, it is imperative to consider the process of light absorption. Light absorption involves the conversion of incident light energy into free electrons, inevitably leading to the generation of thermal energy within the metal. Intriguingly, the thermal effects within plasmonics have often been underappreciated or marginalized by numerous researchers. Since the early 2010s, concerted efforts have been made to visualize and systematically control heat generation within plasmonic nanostructures. However, the complexities surrounding temperature-driven plasmonic nonlinearity persist, and the absence of a suitable measurement methodology has made it challenging to concurrently quantify both light absorption and near-field enhancement. This dissertation addresses these challenges through the development of a thermoplasmonic system tailored to scrutinize the nuanced interplay of light absorption and near-field enhancement—two pivotal facets of plasmonics. In Chapter 2, we introduce methods for quantifying the impact of heat generation in plasmonics. We employ the temperature-dependent Drude Lorentz model and apply an iterative optothermal analysis method to investigate the photothermal effect in various plasmonic nanostructures. In terms of a wire-grid polarizer, contrary to conventional wisdom, our findings indicate that light absorption is more efficient in TM polarization, especially when the wire grid is close to the thin film, resulting in increased heat generation. We also analyze heat dissipation times, demonstrating their independence from polarization and dependence solely on structural properties. Furthermore, we conduct a computational analysis to assess how heat-induced convection affects the behavior of biomolecules in a plasmonic dimer-based fluorescence correlation assay, showing that under the experimental conditions, the temperature rise and convection flow rate can be neglected when analyzing biomolecule behavior. Lastly, we explore the correlation between radiative and non-radiative decay of fluorescent emitters and the distance between metal nanoholes. In Chapter 3, we present an innovative approach that enables the simultaneous measurement of light absorption and near-field enhancement using angle-resolved near-field scanning optical microscopy. The axial shift of the NSOM tip reflects thermal expansion (i.e., light absorption), while the PMT signal measures near-field enhancement in conjunction with the NSOM tip. These results are analyzed through iterative opto-thermal analysis based on temperature-dependent optical properties. Our findings reveal that gold thin films exhibit sub-linear nonlinearity in near-field enhancement due to nonlinear opto-thermal effects. Light absorption displays both sub-linear and super-linear behavior under on/off-resonance conditions at varying thicknesses. These observations align well with predictions based on a simple harmonic oscillation model, where changes in damping parameters affect light absorption and field enhancement differently. The accuracy and sensitivity of our method are experimentally validated by measuring the opto-thermal response of three-dimensional nanostructure arrays. In Chapter 4, we implement a thermoplasmonic excitation and imaging system that combines quadri-wave lateral shearing interferometry with an additional heat path, utilizing a 2-dimensional phase grating. We describe the mathematical techniques and the methodology for extracting temperature from optical path differences while addressing the technology's limitations and proposing solutions. We investigate the thermal response of various nanostructures, such as gratings, nanorods, and films, using the thermoplasmonic excitation and imaging system. Additionally, we design a polarization-sensitive plasmonic heater that can unveil the thermal sensing mechanisms of thermophilic bacteria. It allows us to manipulate temperature distribution on microscale, therefore, we believe that it can be applied to investigate opto-thermal response of diverse bio-samples.

열습하에서 CFRP 원형/사각형 부재의 에너지 흡수 특성

박으뜸 조선대학교 일반대학원 2010 국내석사

CFRP (Carbon Fiber Reinforced Plastic) high-in-tension, according to quality of light weight the sporting goods and the vehicle bonnet, aerospace craft etc. CFRP is used from the field which is various. From specially with the automobile the driver valence according to increasing, the accident valence is increasing same mobile means and the collision accident which is like this the most general region the side or the back side in order to occur plentifully most is one part which is important from general collision at the time of safety decline vehicle development. For a safety consequently shock the research which absorbs is extending plentifully time, at the time of does a safety and a lightweight anger first of all under demand conditions as the shocking absorption absent material. Insect family hour height as the material CFRP was coming to be paid attention like this demand condition, used re-with shocking absorption vice-and increased for experiments to be many wholeheartedly coming a shocking absorption and quantity. But it which has a weakness in compliance with the moisture or moisture the efficiency falls is the thing in as many as like this CFRP. The change of change of temperature and humidity is big management very importance termination according to like this ambient environmental change from the country where the specially, with our country same field of fire paragraph is clear because being the possibility the various branch variable happening is. Gave a temperature and the humidity which are fixed in the specimen from this dissertation and the moisture absorption which follows in CFRP interfaces should have become how many, examined and came to make from under same condition, the specimen and the moisture which constructs comparison of the specimen which absorbs led and the degree of performance degradation of the water absorption at the time of should have changed how many, is examines. And the interface of CFRP complex materials the great part decides the physical properties of the complex material is and according to interface veterinarian change the energy absorption quantity of circular absence be visible what kind of difference, to know, the report person does. 1. CFRP absorption water after to make an environment, according to interface possibility with the sheep of the moisture which absorbs difference of speed is but until before 1% of original weight increases the speed which absorbs speed falls with 1% after that quickly gradually. With 2500 hour after that almost there is not fluctuation about absorption. 2. 2 interfaces absorb most quickly and also the absorption quantity appears most highly at 1.26% and on the other hand 7 interfaces show the absorption quantity which does not reach in 1.09% of circle members. 3. 2 interfaces absorb most quickly and also the absorption quantity appears most highly at 1.19% and on the other hand 7 interfaces show the absorption quantity which does not reach in 1.03% of square members. 4. This result leads and absorption water the within resin of the case interface layer which will do is destroyed and does not become the recovery even to dry after that and the absorption energy quantity decreases in order not to be and there is a possibility of knowing.

Sulfur dioxide capture by absorption process using amino acids from coal-fired power plant flue gas

김광휘 Graduate School, Yonsei University 2024 국내박사

The World Health Organization (WHO) recently warned that the world is facing a global climate crisis owing to rapidly deteriorating air quality. Nevertheless, rapid industrialization and population growth have led to a dramatic increase in the consumption of fossil fuels. Sulfur dioxide (SO2), a combustion product of fossil fuels, can threaten human health and ecosystems in the form of acid rain and smog, and can be converted into sulfate aerosols through photochemical reactions, harming human respiratory systems. The amount of SO2 emitted from coal-fired power plants is significant because coal has a higher sulfur content than other fossil fuels. However, coal-fired power plants still provide a significant portion of the world's electricity supply. Therefore, flue gas desulfurization (FGD) technology to reduce SO2 emissions is a realistic alternative, with wet FGD technology being widely used owing to its superior SO2 removal efficiency. However, the use of limestone, a traditional absorbent in wet FGD technology, is problematic as it generates large amounts of wastewater and fouling, and Korea is facing depletion of high quality limestone owing to the demand for desulfurization. Therefore, in this study, the SO2 absorption/desorption properties of amino acids, which are eco-friendly and highly biodegradable, were investigated to identify their potential as novel SO2 absorbents. In Chapter 3 of this thesis, the SO2 absorption/desorption performance of 14 different amino acid absorbers was evaluated; and in Chapter 4, the effect of molecular structure on SO2 capture was studied by investigating the SO2 absorption/desorption performance of materials with increasing alkyl chain length from the structure of glycine. Chapter 5 investigated the optimal absorbent applicable to the membrane contactor process for desulfurization by adding amino acids to ammonia solution to solve the problem of ammonia escape; and to create a synergistic effect to improve SO2 absorption performance. In Chapter 6, a study was conducted on corrosion inhibition for the application of carbon steel in FGD facilities by using eco-friendly corrosion inhibitors in the absorbent selected in Chapter 5. In conclusion, this study has identified the potential of amino acids as novel SO2 absorbers and we believe that they will make a significant contribution to the commercialization of novel of FGD technology. 최근 세계보건기구(WHO)는 급격히 악화되는 대기질로 인해 전 세계가 기후 위기에 직면하고 있다고 경고했다. 특히, 급속한 산업화와 인구 증가로 인해 화석 연료의 소비가 급격히 증가하면서 연소 산물인 SO2 가 산성비, 스모그 등의 형태로 인간의 건강과 생태계를 위협하며 광화학 반응을 통해 황산염 에어로졸로 전환되어 인간의 호흡기에 해를 끼치고 있다. 따라서 SO2 배출을 저감하기 위한 FGD 기술이 현실적인 대안이며, 습식 FGD 기술은 SO2 제거 효율이 가장 높은 기술로 널리 사용되고 있다. 그러나 기존의 흡수제인 석회석은 다량의 폐수 발생과 배관 막힘 등의 문제가 있으며, 우리나라는 탈황용 석회석의 고갈 문제에 직면하고 있다. 따라서 본 연구에서는 친환경적이고 생분해성이 높은 아미노산의 이산화황 흡착/탈거 특성을 탐구하여 새로운 SO2 흡수제로서의 가능성을 확인하고자 하였다. 먼저, 14 가지 아미노산 흡수제의 SO2 흡수/탈거 성능을 종합적으로 평가하였고, 반응 메커니즘을 규명하였다. 그리고 분자 구조적 차이에 따른SO2 흡수/탈거 성능을 조사하여 분자 구조가 SO2 포집에 미치는 영향을 연구하였다. 또한, SO2/CO2 경쟁 반응 속에서 높은 SO2 선택도를 가져 CO2 포집 공정에 유리한 특성을 확인하였다. 이러한 연구 결과를 통해 아미노산이 재생 가능한 SO2 흡수제로서 차세대 흡수제인 이온성액체 (ILs) 와 공융용매 (DESs)보다 우수함이 확인되었다. SO2 흡수제로서 아미노산의 활용 방안을 확장하기 위해 우수한 SO2 제거 효율로 주목받고 있는 암모니아수의 첨가제로 활용하였다. 이는 암모니아수의 가장 큰 단점인 암모니아 탈출 문제를 해결하고, 아미노산과의 시너지 효과를 통해 SO2 흡수 성능을 향상시켰다. 또한, 흡수제의 물리적 특성을 향상시켜 SO2 포집 기-액 접촉분리막 공정에 적합한 최적의 흡수제를 개발하였다. 그리고 그 최적의 흡수제에 친환경 부식 억제제를 사용하여 FGD 설비에 탄소강 적용을 위한 부식 억제에 대한 연구를 수행하였다. 이러한 다양한 연구를 통해 아미노산이 새로운 SO2 흡수제로서의 역할과 가능성을 확인하였으며, 향후 FGD 기술 발전에 큰 기여할 수 있을 것으로 기대된다.

Excited-state dynamics in donor-acceptor systems for energy conversion

Ochsmann, Julian 서울대학교 대학원 2016 국내박사

현 논문은 ultrafast time-resolved optical spectroscopy를 이용하여 에너지 변환 도너-억셉터 시스템 내의 excited-state dynamics를 다루었다. 현 연구는 bulk-heterojunction morphology를 구성하는 도너 역할의 diketopyrrolopyrrole-based (DPP) low-bandgap copolymer와 억셉터 역할의 fullerene이 혼합된 유기태양전지의 photophysics를 보고하고자 한다. 두 번째 파트는 long-lived charge-separated states을 형성하기 위해 집광성 물질의 porphyrins, 전자받개 quinones과 전자주개 ferrocenes을 사용한 인공 광합성 반응을 주로 다루었다. Time-resolved photoluminescence spectroscopy 와 transient absorption spectroscopy를 이용하여, low-bandgap polymers PTDPP-TT와 PFDPP-TT 내에서 singlet-exciton의 lifetimes이 20ps 미만임을 밝히고, 폴리머와 PC71BM의 blend 상에서 bound charge-transfer states의 geminate recombination이 주요한 loss channel 임을 보고하였다. 또한, polymers triplet states내로 자유전하의 빠른 non-geminate recombination이 두 blend system에서 모두 관찰되었다. PDPP5T:PC71BM 도너-억셉터 시스템 내에서, 높은 끓는 점을 가지는 두 용액 (i.e. ortho-dichlorobenzene (o-DCB))을 사용한 polymer:fullerene blend는 active layer의 모폴로지를 급격하게 변화시키고 태양전지의 효율을 증가시킨다. 이는 친밀히 섞인 도너/억셉터 물질과 전극으로의 뛰어난 percolation으로 인하여 용이한 전하 생성과 extraction을 야기하기 때문이다. Polymer triplet state이 triplet charge-transfer states로부터 형성된 것과 같이 PDPP5T:PC71BM blend system에서 빠른 triplet-state 형성이 관찰되었다. Multivariate curve resolution (MCR) 분석은 전하의 non-geminate recombination이 폴리머 triplet-state과 밀접하게 의존하고 있음을 보여주었다. 인공적인 광합성 반응시, transient absorption spectroscopy은 photoinduced charge transfer이 quinone-porphyrin-ferrocene (Q-P-Fc) triads에서와 같이 quinone-porphyrin (Q-P)와 porphyrin-ferrocene (P-Fc) diads내에서 매우 효과적임을 증명하였다. 그러나 P-Fc 와 Q-P-Fc system내에서 전하분리상태는 각각의 porphyrin triplet state와 재결합함을 보여주었다. 현 논문은 ultrafast time-resolved optical spectroscopy를 이용하여 에너지 변환 도너-억셉터 시스템 내의 excited-state dynamics를 다루었다. 현 연구는 bulk-heterojunction morphology를 구성하는 도너 역할의 diketopyrrolopyrrole-based (DPP) low-bandgap copolymer와 억셉터 역할의 fullerene이 혼합된 유기태양전지의 photophysics를 보고하고자 한다. 두 번째 파트는 long-lived charge-separated states을 형성하기 위해 집광성 물질의 porphyrins, 전자받개 quinones과 전자주개 ferrocenes을 사용한 인공 광합성 반응을 주로 다루었다. Time-resolved photoluminescence spectroscopy 와 transient absorption spectroscopy를 이용하여, low-bandgap polymers PTDPP-TT와 PFDPP-TT 내에서 singlet-exciton의 lifetimes이 20ps 미만임을 밝히고, 폴리머와 PC71BM의 blend 상에서 bound charge-transfer states의 geminate recombination이 주요한 loss channel 임을 보고하였다. 또한, polymers triplet states내로 자유전하의 빠른 non-geminate recombination이 두 blend system에서 모두 관찰되었다. PDPP5T:PC71BM 도너-억셉터 시스템 내에서, 높은 끓는 점을 가지는 두 용액 (i.e. ortho-dichlorobenzene (o-DCB))을 사용한 polymer:fullerene blend는 active layer의 모폴로지를 급격하게 변화시키고 태양전지의 효율을 증가시킨다. 이는 친밀히 섞인 도너/억셉터 물질과 전극으로의 뛰어난 percolation으로 인하여 용이한 전하 생성과 extraction을 야기하기 때문이다. Polymer triplet state이 triplet charge-transfer states로부터 형성된 것과 같이 PDPP5T:PC71BM blend system에서 빠른 triplet-state 형성이 관찰되었다. Multivariate curve resolution (MCR) 분석은 전하의 non-geminate recombination이 폴리머 triplet-state과 밀접하게 의존하고 있음을 보여주었다. 인공적인 광합성 반응시, transient absorption spectroscopy은 photoinduced charge transfer이 quinone-porphyrin-ferrocene (Q-P-Fc) triads에서와 같이 quinone-porphyrin (Q-P)와 porphyrin-ferrocene (P-Fc) diads내에서 매우 효과적임을 증명하였다. 그러나 P-Fc 와 Q-P-Fc system내에서 전하분리상태는 각각의 porphyrin triplet state와 재결합함을 보여주었다. This thesis covers the investigation of excited-state dynamics in donor-acceptor systems for energy conversion by means of ultrafast time-resolved optical spectroscopy. The main part of this work focuses on the photophysics of organic solar cells consisting of diketopyrrolopyrrole-based (DPP) low-bandgap copolymers as electron donors blended with fullerenes as electron acceptors in a bulk-heterojunction morphology. A second part is dedicated to the study of artificial primary photosynthetic reaction centers based on porphyrins, quinones and ferrocenes as light harvesting, electron accepting, and electron donating moiety, respectively, with the aim to create long-lived charge-separated states. Time-resolved photoluminescence spectroscopy and transient absorption spectroscopy revealed that singlet-exciton lifetimes in the low-bandgap polymers PTDPP-TT and PFDPP-TT are short (< 20 ps) and that in blends of the polymers with PC71BM geminate recombination of bound charge-transfer states is a major loss channel. In addition, fast non-geminate recombination of free charges into the polymers triplet states was observed in both blend systems. For the PDPP5T:PC71BM donor-acceptor system it was found that processing the polymer:fullerene blend with a high-boiling point co-solvent, i.e. ortho-dichlorobenzene (o-DCB), drastically changes active layer morphology and increases solar cell performance, due to more intimately mixed donor and acceptor materials and pronounced percolation pathways to the electrodes, facilitating charge carrier generation and extraction. Fast triplet-state formation was observed in both of the PDPP5T:PC71BM blend systems, as the polymer triplet state can be populated from triplet charge-transfer states. Multivariate curve resolution (MCR) analysis showed a strong fluence dependence pointing to non-geminate recombination of charges into the polymer triplet state. On the artificial primary photosynthetic reaction centers transient absorption spectroscopy verified that photoinduced charge transfer is efficient in quinone-porphyrin (Q-P) and porphyrin-ferrocene (P-Fc) diads as well as in quinone-porphyrin-ferrocene (Q-P-Fc) triads. However, it was also shown that in the P-Fc and Q-P-Fc systems the charge-separated states recombine into the respective porphyrin triplet state. The charge-separated state in the Q-P diad could significantly be stabilized upon the addition of a Lewis acid. In dieser Arbeit werden die Dynamiken angeregter Zustände in Donor-Akzeptorsystemen für Energieumwandlungsprozesse mit ultraschneller zeitaufgelöster optischer Spektroskopie behandelt. Der Hauptteil dieser Arbeit legt den Fokus auf die Erforschung der Photophysik organischer Solarzellen, deren aktive Schichten aus diketopyrrolopyrrole (DPP) basierten Polymeren mit kleiner Bandlücke als Elektronendonatoren und Fullerenen als Elektronenakzeptoren bestehen. Ein zweiter Teil widmet sich der Erforschung von künstlichen primären Photosynthesereaktionszentren, basierend auf Porphyrinen, Quinonen und Ferrocenen, die jeweils als Lichtsammeleinheit, Elektronenakzeptor beziehungsweise als Elektronendonatoren eingesetzt werden, um langlebige ladungsgetrennte Zustände zu erzeugen. Zeitaufgelöste Photolumineszenzspektroskopie und transiente Absorptions-spektroskopie haben gezeigt, dass Singulettexzitonenlebenszeiten in den Polymeren PTDPP-TT und PFDPP-TT Polymeren kurz sind (< 20 ps) und dass in Mischungen der Polymere mit PC71BM geminale Rekombination von gebundenen Ladungstransferzuständen ein Hauptverlustkanal ist. Zudem wurde in beiden Systemen schnelle nichtgeminale Rekombination freier Ladungen zu Triplettzuständen auf dem Polymer beobachtet. Für das Donor-Akzeptor System PDPP5T:PC71BM wurde nachgewiesen, dass die Zugabe eines Lösungsmittels mit hohem Siedepunkt, und zwar ortho-Dichlorbenzol, die Morphologie der aktiven Schicht stark beeinflusst und die Solarzelleneffizienz verbessert. Der Grund hierfür ist, dass die Donator- und Akzeptormaterialien besser durchmischt sind und sich Perkolationswege zu den Elektroden ausgebildet haben, was zu einer verbesserten Ladungsträgergeneration und Extraktion führt. Schnelle Bildung des Triplettzustands wurde in beiden PDPP5T:PC71BM Systemen beobachtet, da der Triplettzustand des Polymers über Laungstransferzustände mit Triplettcharakter populiert werden kann. "Multivariate curve resolution" (MCR) Analyse hat eine starke Intensitätsabhängigkeit gezeigt, was auf nichtgeminale Ladungsträgerrekombination in den Triplettzustand hinweist. In den künstlichen primären Photosynthesereaktionszentren hat transiente Absorptionsspektroskopie bestätigt, dass photoinduzierter Ladungstransfer in Quinon-Porphyrin (Q-P) und Porphyrin-Ferrocen (P-Fc) Diaden sowie in Quinon-Porphyrin-Ferrocen (Q-P-Fc) Triaden effizient ist. Es wurde jedoch auch gezeigt, dass in den P-Fc unf Q-P-Fc Systemen die ladungsgetrennten Zustände in den Triplettzustand der jeweiligen Porphyrine rekombinieren. Der ladungsgetrennte Zustand konnte in der Q-P Diade durch Zugabe einer Lewissäure signifikant stabilisiert werden.

목재 실내 건축마감재의 흡습·방습 성능평가에 관한 연구

하우 전북대학교 일반대학원 2022 국내석사

In this study, three representative softwood tree species and two representative hardwood tree species used as interior finishing materials were reviewed for applicability as functional building finishing materials for moisture absorption and moisture desorption with a view to improving moisture absorption and moisture desorption performances. The government has established and is operating the ‘Health-friendly Housing Construction Standards’ (Ministry of Land, Infrastructure and Transport, 2019) and green technology (functional building materials). According to the foregoing, the performance standard for moisture absorption and moisture desorption functional building materials was set to at least 65 g/m2 under the Health-friendly Housing Construction Standards. In addition, in the green technology (functional building material) sector under the Framework Act on Low-Carbon, Green Growth, the average moisture absorption/desorption amount was specified and is being implemented to be at least 85 g/m2. Five wood tree species were used in the tests in this study, which are Hinoki, Douglas fir, Sugi, Oak, and Maple, and the tests were conducted according to the method under the Korean Industrial Standard KS F 2611: 2009 (Test method for moisture absorption and desorption of building materials). In the experiments in this study, the basic moisture absorption and desorption performance of wood and the effect of physical processing to improve the moisture absorption and desorption performance were evaluated. In addition, the dimensional changes caused by moisture absorption and moisture desorption were evaluated by type of physical processing in order to present the applicability of the wood materials as functional building materials for moisture absorption and moisture desorption. Through previous studies, wood is known to be a porous material with excellent humidity regulation performance but through the tests in this study, the wood materials were evaluated as not satisfying the moisture absorption and desorption standards presented by the government. In this study, increasing the surface porosity and specific surface area through physical processing to improve the performance was evaluated to be capable of giving more excellent moisture absorption and desorption performances to wood but it was judged that for the wood materials to be used as functional building materials for moisture absorption and moisture desorption that satisfy the Korean industrial standard, improvement through additional processing (chemical processing, etc.) is necessary.

객석바닥 경사각 변화가 장방향실의 객석 흡음률에 미치는 영향

차창혁 전북대학교 일반대학원 2022 국내석사

A raked audience area has been used in various places to help audience have good sight-lines without significant direct sound energy losses. In particular, a vineyard shaped concert hall, which consists of various raked seating area, has been known to offer the possibility of providing early reflections to majority of audience and steeply raked balcony make it possible for audience to be close to stage. Although chairs and human body in raked audience area would be well exposed to the sound field, sufficient information to meet requirements about absorption of raked audience area is not available for initial acoustic design. Eventually, inaccurate absorption of audience area can cause a significant disagreement between predicted acoustic values and evaluated acoustic conditions after constructed, especially, for reverberation time which is once regarded as the predominant indicator of its acoustical properties in a room. Beranek and Kuttruff have stated with logical reasoning that the sound absorption by seating area would increase as the floor slope gets higher. Also, Hegvold has shown similar results after a series of 1/10 scale model experiments. However, Beranek and Kuttruff’s hypothesis needs a precondition in that exposed audience and chair to direct sound should be highly absorptive, such as mid-season clothes as are used in Hegvold’s experiment. Strict dress code is not mandatory in recent year while clothes restriction for audience was prevalent in most of theatres and concert halls in the past. Moreover, the amount of clothing worn by audience tends to change depending on the weather condition. Therefore, it seems to be unavoidable that audience area absorption is highly dependent on the weather condition, since lightly clothes and human skin are rather reflective while mid-season clothing tends to be absorptive. Several studies on audience body and skin in seating area have been published. Kirkegaard has stated that seasonal clothing is critical in concert halls and other rooms, and Katz has demonstrated that human skin is acoustically rigid, with absorption coefficient"(α)= 0.03" , Mommretz and Tahvanainen have described that audience shoulder and knee indeed reflect sound. In other words, absorption of raked seating area might not be increased compared to absorption of flat seating area, if audience skin and summer clothes were exposed to direct sound. This study tried to provide a practical research data for initial acoustic design process through a series of 1/15 scale model experiments. Three variables for audience area, changes in floor rake angle (0 to 35 degrees, 5 degrees steps), the amount of sound absorption of chairs, and seasonal changes in audience clothing were considered. In order to evaluate the subjective effect of absorption change caused by audience area condition, this study defined new 1 JND of absorption coefficient by using 1 JND of reverberation time based on the ISO-3382. Any change in sound absorption coefficients by varying experimental condition of audience area which exceeds 1 JND was regarded as having significant subjective effects on audience in the present work. The results from this work suggested that the audience area consisted of low absorption of chair and summer clothes seems not to be influenced by the change in floor rake angle, which is due to the reflective area of back rest, seat pan and human skin. On the other hand, absorption coefficient of the audience area consisted of high absorption chair and spring/autumn clothes is getting higher as the floor rake is increased up to 20 or 25 degrees. This result proposed that the effect of porous absorbing material of chair and clothes on the sound absorption, exposed to direct sound, tends to be stronger as the floor rake gets steeper. The change in absorption coefficient of audience area larger than 1 JND was not observed, and decreasing tendency by more than 1 JND was found in some cases, when the floor rake exceeds 20 or 25 degrees. The analysis of direct sound distribution on the cross-section of audience area suggests that the under space of chair and audience knee are begun to be exposed to the direct sound as the floor rake is larger than 20 or 25 degrees. Furthermore, when floor degree is larger than 20 degrees, absorption coefficient at 4 kHz of occupied high absorption chair with audience in summer clothes gets lower than those of unoccupied high absorption chair. This can be explained that audience wearing summer clothes is well exposed to direct sound relative to heavily absorbing materials of chair, it is so called ‘shadowing effect’. Therefore, absorption of raked seating area depends on the portion of chair which are exposed to the incident sound and its degree of absorptive treatment.