23 research outputs found
μ½λ μ€ννΈ λΉλμ€ μΆμ²μμ€ν μ μν 컨ν μΈ νν νμ΅
νμλ
Όλ¬Έ(μμ¬) -- μμΈλνκ΅λνμ : λ°μ΄ν°μ¬μ΄μΈμ€λνμ λ°μ΄ν°μ¬μ΄μΈμ€νκ³Ό, 2023. 2. μ΄μ€μ.Cold-start item recommendation is a long-standing challenge in recommendation systems. A common approach to tackle cold-start problem is using content-based approach, but in movie recommendations, rich information available in raw video contents or textual descriptions has not been fully utilized. In this paper, we propose a general cold-start recommendation framework that learns multimodal content representations from the rich information in raw videos and text, directly optimized over user-item interactions, instead of using embeddings pretrained on proxy pretext task. In addition, we further exploit multimodal alignment of the item contents in a self-supervised manner, revealing great potential in content representation learning. From extensive experiments on public benchmarks, we verify the effectiveness of our method, achieving state-of-the-art performance on cold-start movie recommendation.μ½λ μ€ννΈ μμ΄ν
μΆμ²μ μΆμ²μμ€ν
μ°κ΅¬μμ μ€λλ λ¬Έμ μ€ νλμ΄λ€. μ½λ μ€ννΈ λ¬Έμ λ₯Ό ν΄κ²°νκΈ° μν΄ νν μ¬μ©ν΄μ¨ λ°©λ²μ 컨ν
μΈ κΈ°λ° μ κ·Ό λ°©μμ μ¬μ©νλ κ²μ΄μ§λ§, μν μΆμ² μμ€ν
λΆμΌμμλ μλ³Έ λΉλμ€ λ° μλ¬Έ μ€λͺ
λ±μ λ΄μ¬λ νλΆν μ 보λ₯Ό μΆ©λΆν νμ©ν΄μ€μ§ λͺ»νλ€. λ³Έ λ
Όλ¬Έμμ μ μνλ μ½λ μ€ννΈ μΆμ² νλ μμν¬μμλ μλ³Έ λΉλμ€μ ν
μ€νΈμ νλΆν 컨ν
μΈ μ 보λ₯Ό κΈ°λ°μΌλ‘ λ©ν°λͺ¨λ¬ 컨ν
μΈ ννμ νμ΅νλ κ³Όμ μμ, λ€λ₯Έ νμ€ν¬μ μ¬μ νμ΅λ μλ² λ©μ νμ©νλ λμ μ μ -μμ΄ν
μνΈμμ© μ 보λ₯Ό μ΄μ©νμ¬ μ§μ μλ² λ©μ μ΅μ ννλ λ°©λ²μ μ μνλ€. λ λμκ°, λ³Έ μ°κ΅¬λ μκΈ° μ§λ νμ΅ λ°©λ²μ ν΅ν΄ μ¬λ¬ λͺ¨λ¬λ¦¬ν°λ‘ ννλμ΄ μλ μμ΄ν
컨ν
μΈ λ₯Ό κ³ λ €ν¨μΌλ‘μ¨ μ»¨ν
μΈ νν νμ΅μ λ°μ κ°λ₯μ±μ μ¬μ‘°λͺ
νλ€. μ΅μ’
μ μΌλ‘ μ£Όμ λ²€μΉλ§ν¬ λ°μ΄ν°μ
μ λν λ€μν μ€νμ ν΅ν΄ λ³Έ μ°κ΅¬μμ μ μνλ λ°©λ²λ‘ μ ν¨κ³Όλ₯Ό μ
μ¦ν¨κ³Ό λμμ μ½λ μ€ννΈ μν μΆμ² λΆμΌμμ ν΄λΉ λΆμΌ μ΅κ³ μ±λ₯μ 보μ΄λ μ¬μ€μ νμΈνμλ€.Chapter 1. Introduction 1
Chapter 2. Related Work 7
Chapter 3. Problem Formulation and Notations 10
Chapter 4. Preliminary 12
Chapter 5. The Proposed Method 16
Chapter 6. Experimental Settings 24
Chapter 7. Results and Discussion 28
Chapter 8. Summary and Future Work 36
Bibliography 37
Abstract in Korean 45μ
μ°λ°©μ νμμμ λΉ λ₯Έ ν΅μΌ: 1990λ ν΅μΌκ³Όμ μμ μλ μ§λ°©μ λΆμ μ νΈμ κ΄ν μ°κ΅¬
νμλ
Όλ¬Έ (μμ¬)-- μμΈλνκ΅ κ΅μ λνμ : κ΅μ νκ³Ό(κ΅μ νλ ₯μ 곡), 2013. 8. μ΄κ·Ό.μ±κΈν ν΅μΌμ΄ κ°μ Έμ¬ μ μλ κ²½μ μ λΆμμ©μ λν΄ λΉμ μ΄λ―Έ λ§μ κ²½μ νμλ€μ΄ μ§μμ μΌλ‘ κ²½κ³ νμμλ λΆκ΅¬νκ³ , μ μλ
μ μ§λ°©μ λΆλ€μ λΉ λ₯Έ μλμ ν΅μΌμ μ§μ§νμλκ°? μ΄μ λν λ΅μ μ°ΎκΈ° μν΄ 1990λ
μλ
μ μ λΉμ μΉλ₯Ό μ°λ°© μμ€ν
μ΄λΌλ λ§₯λ½ μμμ, νΉν μλ
μ§λ°©μ λΆμ μ νΈμ κ΄μ¬μ κ°μ§κ³ μ΄ν΄ 보μλ€. μ°λ°©μ νμ μ λΉμ μΉμ κ΄ν κΈ°μ‘΄μ μ°κ΅¬λ€μ μ°λ°© μμ€μμ νλνλ μ λΉμ νμμ μ΄μ μ λ§μΆλ©΄μ, μ§μμ μ νΈμλ ν° κ΄μ¬μ κΈ°μΈμ΄μ§ μμλ€. μ΄λ¬ν λ§Ήμ μ 보μνκΈ° μν΄, λ³Έ λ
Όλ¬Έμ Kahnemanκ³ΌTverskyμ μ λ§μ΄λ‘ μ λ°νμΌλ‘ μ§λ°©μ λΆμ μ νΈλ₯Ό λΆμνμλ€. 1990λ
μ μ€μλ μΈ μ’
λ₯μ μ¬λ‘ μ‘°μ¬μ, μ°λ°©μμκ³Ό μ°λ°©νμμ λ¬Έμλ€, κ·Έλ¦¬κ³ κΈ°λ―ΌλΉκ³Ό μ¬λ―ΌλΉμ λΉλ΄ μμμ§μ λν μ§μ λΆμμ΄ μ΄λ£¨μ΄μ‘λ€. λ
μΌν΅μΌμ λν μ°λ°©μμμ ν λ‘ νλμ μ°λ°©νμμ ν λ‘ λ€ κ°μ λνμ¬ λ¨μ΄ μ μ¬μ±μ λ°λ₯Έ κ΅°μ§λΆμλ μ€μλμλ€. λΆμμ μ£Όμκ²°κ³Όλ λ€μμ μΈκ°μ§λ‘ λνλ¬λ€. 첫째, μλ
μ§λ°©μ λΆλ ν΅μΌ μ΄μ μ κ²½μ μ μ§μμμ νμ±λ μ°Έμ‘°μ μ κΈ°λ°νμ¬ μ νΈλ₯Ό νμ±νμλ€. μμ λ€μ κ²½μ μ νμμ μ§λ₯Ό μν΄ μ§λ°©μ λΆλ ν΅μΌλ‘λΆν° μμΈ‘λλ λ κ°μ§ κ²½μ μ μμ€ β μ΄λ―Όμ μ¦κ°μ κ΅κ°μ¬μ λΆλ΄ μ¦κ° βλ₯Ό νΌνλ € νμλ€. λμ§Έ, μ§λ°©μ λΆλ μ₯κΈ°μ μμ€λ³΄λ€λ λ¨κΈ°μ μμ€μ λνμ¬ λ ν° ννΌμ±μ 보μ΄λ λ± μ λ°μ μΌλ‘ κ·Όμμμ μΈ μ νΈλ₯Ό λνλλ€. 1990λ
μλ°κΈ°μλ λλ
μΌλ‘λΆν°μ μ΄λ―Όμ μ¦κ°κ° λ¨κΈ°μ μμ€λ‘ μΈμλμλλ°, μ΄κ²μ λ
μΌλ―Όμ‘±μ μ°λ°©κ΅κ²½ μΆμ
μ κ΄ν λ²λ₯ (Aufnahmegesetz)μ λΉνΈ μλ λ€μμ μ΄λ―Όμκ° κΈκ²©ν μ μ
λμκΈ° λλ¬Έμ΄λ€. 1990λ
νλ°κΈ°μλ κΈμν μ
νλ λλ
κ²½μ λ‘ μΈν΄ ν΅μΌμκΈμ‘°λ¬μ΄ λ¨κΈ°μμ€λ‘ μΈμλμλ€. μ
μ§Έ, ν΅μΌκ³Όμ μμ μ§κΆλΉ(κΈ°λ―ΌλΉ/κΈ°μ¬λΉκ³Ό μλ―ΌλΉ μ°ν©)μ΄ μ 1μΌλΉ(μ¬λ―ΌλΉ)λ³΄λ€ λ μ£Όλμ μΈ λͺ¨μ΅μ 보μλλ°, μ΄λ¬ν μ£ΌλκΆμ μ§κΆλΉμ λ κ°μ§ μ μ±
βμΆμ
λ²μ νμ§ λ° λ
μΌ ν΅μΌ κΈ°κΈ μ μ€-μ κΈ°μΈνλ€. μ΄ λ κ°μ§ μ μ±
λ€μ κ°κ° μ΄λ―Όμ μ¦κ°μ ν΅μΌμκΈμ‘°λ¬μ λν μ§λ°©μ λΆμ μμ€ννΌλ₯Ό μ±κ³΅μ μΌλ‘ νμ©ν κ²μ΄μλ€. λ³Έ λ
Όλ¬Έμ μ΄λ¬ν λ°κ²¬μ νλ°λ ν΅μΌμ λν κΈ°μ‘΄ μ°κ΅¬λ€μ΄ ν΅μΌμ μ¬λ¦¬μ μΈ‘λ©΄μ κ°κ³Όν΄ μμμ λΉμΆμ΄ λ³Ό λ, μΆν μ°κ΅¬μ μμ¬νλ λ°κ° ν¬λ€.Why did West German regional governments approve the swift pace of German unification, despite the fact that many economic experts repeatedly warned of economic side-effects of a rapid approach to unification? West German party politics during 1990 is examined in the context of federal system, to answer this question. A special emphasis is placed on the preferences of regional governments in West Germany. Previous studies of party politics in federal systems focused on behaviors of central party leaderships and paid little attention to regional preferences. To fill in this missing gap, this thesis adopts prospect theory from Kahneman and Tversky as an analytical framework to localize these preferences to regional governments. Three public opinion polls, parliamentary documents of the Bundestag and the Bundesrat, and intra-party magazines of the CDU and the SPD are analyzed. A cluster-analysis by word similarity is conducted for one Bundesrat debate and four Bundestag debates over German unification. There are three major findings. First, West German regional governments formed their preference based on a reference point at the pre-unification economic status quo. To safeguard their economic status quo, regional governments attempted to avoid two major economic losses expected from unification β increased immigration from East Germany and increased burden of public finance to support unification. Second, regional governments tended towards a myopic preference, with greater loss-avoidance for a short-run loss than for a long-run loss. In the first half of 1990, an increase in East German immigrants was perceived as a short-run loss, due to a huge tide of migration inflows under the Entrance Law (Aufnahmegesetz). In the second half of 1990, against the backdrop of the aggravating East German economy, unification financing was perceived as a short-run loss. Third, the incumbent parties (CDU/CSU-FDP) were more successful than the major opposition party (SPD) in unification initiatives, thanks to their two policy instruments β abolition of the Entrance Law and creation of the German Unity Fund. These two policies respectively made a good use of regional governments loss-avoidance for immigration increase and unification financing. Findings of this thesis have significant implications for future studies of Korean unification, given the earlier academic negligence of psychological aspects of the unification process.Abstract i
List of Figures iv
List of Tables v
Abbreviations and Acronyms vi
Π.Introduction 1
A.The Puzzle 1
B.Previous Studies 3
1.Previous Studies of German Unification 3
2.Previous Studies of West German Party Politics in 1990 5
C.Research Question 8
β
‘.Analytical Framework 10
A.Previous Studies of Political Parties in Federal Systems 10
B.Prospect Theory 12
C.Propositions 17
D.Methodology 22
1.Analytical Objectives 22
2.Data 23
3.Methods 24
β
’.The Federal System of West Germany and German Unification 26
A.The Federal System of West Germany: Cooperative Federalism 26
B.Party Politics under the West German Federal System 31
C.German Unification under the West German Federal System 35
1.Legislative Process of the First State Treaty (The GEMSU Treaty) 36
2.Legislative Process of the Second State Treaty (The Unification Treaty) 39
β
£.Before German Economic, Monetary, and Social Union: January-June 1990 44
A.West German Public Reference Point at the Pre-Unification State of Wealth 44
B.Immigration from East Germany 49
1.Increase in Immigration from East Germany 49
2.Law for the Entrance of Germans to the Federal Border 50
3.Short-Run Loss-Avoidance of West German Regional Governments 52
4.Party Politics 55
C.Unification Financing 60
1.Public Finance: Institutionalized Rules & Procedures 60
2.Future-Cost-Discounting of West German Regional Governments 61
3.Party Politics 69
β
€. After German Economic, Monetary, and Social Union:July-December 1990 75
A.Immigration from East Germany: Decreased Concerns 75
B.Unification Financing 79
1.Economic Problems of East Germany after the GEMSU 79
2.Short-Run Loss-Avoidance of West German Regional Governments 80
3.Party Politics 87
C.All-German Federal Election 92
1.Electoral Campaigns 93
2.Election Results 97
β
₯. Conclusion 101
A.Thesis Summary 101
B.Different Patterns of Loss-Avoidance for Immigration&Unification Financing 103
C.Implications for Korean Unification 105
1.Growing Economic Inequality between the Two Koreas 105
2.Existing Studies of Unification Costs 106
3.Lessons for Korean Unification 107
D.Future Studies 109
Bibliography 111
κ΅λ¬Έμ΄λ‘ 129Maste
Synthesis of Architecture-Controlled Poly(ethylene oxide)s as Biocompatible Materials
νμλ
Όλ¬Έ (λ°μ¬)-- μμΈλνκ΅ λνμ : μ¬λ£κ³΅νλΆ, 2014. 2. μμ² ν¬.Poly(ethylene oxide)s are well known biocompatible, non-toxic, anti-fouling materials in biomedical fields and have been used for applications such as drug delivery, gene therapy, imaging modality and surface modification of carriers. Molecular weight, molecular weight distribution and primary architecture of poly(ethylene oxide) can be precisely controlled employing anionic polymerization of ethylene oxide in a high-vacuum system. 4-arm, 6-arm, 8-arm star-shaped poly(ethylene oxide)s were synthesized using pentaerythritol, sorbitol and 4-arm star-shaped poly(ethylene) oxide precursor as initiators. All polymerizations were carried out in DMSO based on 30 mole% activation of hydroxyl groups in initiators to minimize the side reaction of DMSO activation by DPMK catalyst, known as dimsyl anion formation. Dendritic poly(ethylene oxide)s were prepared in the same condition. Linear, star-shaped, dendritic poly(ethylene oxide)s were synthesized and surface modification at focal point as well as at each peripheral end was successfully controlled. All the polymers were characterized using 1H NMR, GPC and UV spectrometer.
Anionic polymerization of poly(ethylene oxide)s produced the polymers with very narrow molecular weight distribution, which is an important requirement for a biomaterial applicable to drug and cell delivery system in vivo. For delivery of anticancer drugs on tumor site, nanostructures were used for efficiency in delivery and minimized side effects. Block copolymers consisting of 5 K poly(ethylene oxide), functionalized middle block and 2 K poly(caprolactone) were synthesized. Cysteine residues with thiol pendent group were introduced as a functionalized block between two polymers for enhanced stability during blood stream and selective degradation at a targeted site. Doxorubicin was used as anticancer drug and drug loaded nanoparticles displayed the size of 221 nm. Doxorubicin-loading amount and efο¬ciency was around 8.7 and 26.0 %, respectively. Release proο¬le of doxorubicin was monitored under two different conditions with the presence as well as absence of DTT and selective drug release at intracellular condition was observed.
8-arm star-shaped and dendritic poly(ethylene oxide)s were obtained without any noticeable side reactions. Molecular weight was 80 K with narrow molecular weight distribution of 1.03 and functionalized end groups were utilized for islet surface modification as well as double layer coating with unfractionated heparin (UFH). Two catechol groups in average were conjugated at the peripheral ends of 8-arm star poly(ethylene oxide)s and reacted with either thiol or amine groups on the cell surface in mild condition. Cell coverage and viability were optically visualized by FITC dyes which were additionally conjugated at the unreacted ends of the polymers. Modification of cell surface with double layers of poly(ethylene oxide)s and ultra fractionated heparin did not significantly affect the viability and biological functions of islets in vitro and in vivo.
Dendritic poly(ethylene oxide)s were applied for islet modification with the similar method as star-shaped poly(ethylene oxide)s. Dendritic poly(ethylene oxide)s were activated by NHS at the focal point for the conjugation with amine groups on the islet surface. In vivo immunoprotection effects were investigated and dendritic poly(ethylene oxide)-modified islets showed high coverage effect and viability compared to unmodified islets.Chapter 1. Introduction 1
1.1. Poly(ethylene oxide)s in Biomedical Area 2
1.2. Anionic Polymerization 6
1.3. Drug Delivery System for Cancer Therapy 10
1.4. Cell Delivery System for Islet transplantation 15
1.5. Research Objectives 19
1.6. References 24
Chapter 2. Synthesis of Poly(ethylene oxide)s via Anionic Polymerization 28
2.1. Introduction 29
2.2. Experimental Section 35
2.3. Results and Discussion 57
2.4. Conclusion 60
2.5. References 61
Chapter 3. Reduction-sensitive Polymeric Nanoparticles for Drug Delivery System 64
3.1. Introduction 65
3.2. Experimental Section 67
3.3. Results and Discussion 74
3.4. Conclusion 83
3.5. References 84
Chapter 4. 8-Arm Star-shaped Poly(ethylene oxide)s for Cell Delivery 87
4.1. Introduction 88
4.2. Experimental Section 91
4.3. Results and Discussion 98
4.4. Conclusion 110
4.5. References 110
Chapter 5. Dendritic Poly(ethylene oxide)s for Cell Delivery 113
5.1. Introduction 114
5.2. Experimental Section 117
5.3. Results and Discussion 128
5.4. Conclusion 139
5.5. References 140
κ΅λ¬Έμμ½ 142Docto
μ¬λ¦¬μ λΆμμ κ΄ν μμ μ°κ΅¬
νμλ
Όλ¬Έ(μμ¬)--μμΈλνκ΅ λνμ :μ‘°μκ³Ό μ‘°μμ 곡,2004.Maste
Analysis of GAN-based Domain Adaptation
νμλ
Όλ¬Έ(μμ¬)--μμΈλνκ΅ λνμ :μμ°κ³Όνλν ν΅κ³νκ³Ό,2020. 2. κΉμ©λ.κΈ°κ³νμ΅μμ νλ ¨ λ°μ΄ν°μ νκ° λ°μ΄ν°λ λμ§μ μΈ λΆν¬μμ λ
립μ μΌλ‘ μΆμΆλ νλ³Έμ΄λΌκ³ μκ°νλ€. νμ§λ§ μ€μ κΈ°κ³νμ΅μ΄ μ μ©λλ μν©μμλ νλ ¨ λ°μ΄ν°μ νκ° λ°μ΄ν°μ λΆν¬κ° μμ΄ν κ²½μ°κ° μ‘΄μ¬νλ€. κ·Έλ κΈ° λλ¬Έμ μλ‘ λ€λ₯Έ λλ©μΈμμ μ μλνλ νμ΅ λ°©μμ λν μ°κ΅¬κ° μ΄λ£¨μ΄μ§κ³ μμΌλ©° μ΄λ₯Ό λλ©μΈ μμμ΄λΌκ³ νλ€. λ³Έ λ
Όλ¬Έμμλ λ λλ©μΈ κ° νΉμ§ 곡κ°μ divergenceκ° ν° μν©μ κ°μ νμ¬ μλ‘ λ€λ₯Έ λΆλ₯ λͺ¨νμ λλ©μΈ μμμ ν¨κ³Όλ₯Ό λΆμνκ³ μ νλ€. λλ©μΈ μμ λΆμΌμμ λ리 μ¬μ©λλ λλ©μΈ μ λμ μ κ²½λ§(DANN)μ λ λλ©μΈ κ° κ³΅μ νλ νΉμ§λ§΅μ νμ΅νλ κ²μ λͺ©νλ‘ νλ€. λ°λ©΄ μμ±μ μ λ μ κ²½λ§(GAN) κΈ°λ° λλ©μΈ μμ λͺ¨νμ μμ² λλ©μΈμ νΉμ§λ§΅μ΄ μ£Όμ΄μ‘μ λ λͺ©ν λλ©μΈμ νΉμ§λ§΅κ³Όμ λΆλ₯λ₯Ό μ΄λ ΅κ² λ§λλ μμ°¨ κ°λ
μ νΉμ§λ§΅μ νμ΅νλ€. λ°λΌμ λ λλ©μΈ κ° κ³΅μ νλ νΉμ§ 곡κ°μ νμ΅νκΈ° μ΄λ €μ΄ κ²½μ° DANNλ³΄λ€ μ°μν μ±λ₯μ 보μΈλ€. λ³Έ μ°κ΅¬μμλ μ«μ μ΄λ―Έμ§ μλ£λ₯Ό μ¬μ©νμ¬ λ λͺ¨νμ λλ©μΈ μμ ν¨κ³Όλ₯Ό λΆμμλ€.General assumption of machine learning is training and test data are sampled from homogeneous distribution. However, there are some cases where the distribution of training and test data are different in real world problem. For this reason, research is being done on learning strategy to make model work well on both domains. In this study, assumption of huge difference of feature space between source and target domain is made. The main purpose of analysis is domain adaptation effect of various deep neural classification models. Domain-Adversarial Neural Network(DANN)(Ganin et al., 2015), widely used for domain adaptation, aims to learn feature maps which shared between two domains. GAN-Based Domain adaptation model, on the other hand, generates a feature map of the residual concept to achieve domain adaptation. Therefore, performance is better than DANN unless the functional space is shared between the two domains. In this study, numerical image data is used to analyze the domain adaptation effects of both models.1. μλ‘ 1
2. λΆμ λ°©λ²λ‘ 4
2.1 λλ©μΈ μμ κ°μ 4
2.2 λλ©μΈ μ λμ μ κ²½λ§ (DANN) 5
2.3 GAN κΈ°λ° λλ©μΈ μμ μ κ²½λ§ 7
3. μ€ν 11
3.1 μλ£ 11
3.2 ꡬν μΈλΆ μ¬ν 13
3.3 μ±λ₯ λΉκ΅ 16
4. κ²°λ‘ 20Maste
Simultaneous Removal of Both Cesium and Iodate using Prussian Blue Functionalized CoCr Layered Double Hydroxides (PB-LDH)
Masterλ°©μ¬μ± μΈμκ³Ό μμ€λλ νλ°μ±κ³Ό μ©ν΄λκ° λμ μμλ ₯ λ°μ μ μ¬κ³ μ μμ° μμΌλ‘ μ μΆλκΈ° μ¬μ΄ ν΅μ’
μ΄λ€. μ΄λ¬ν λ°©μ¬μ± μΈμκ³Ό μμ€λλ₯Ό μ κ±°νκΈ° μν΄ λ€μν ν‘μ°©μ λ€μ΄ κ°λ°λκ³ μλ€. κ·Έ μ€ νλ¬μμλΈλ£¨λ μ μ΄κΈμκ³Ό μμμ΄μ¨μΌλ‘ ꡬμ±λ λ©΄μ¬μ
방ꡬ쑰 ννλ₯Ό κ°μ§κ³ μλ νλμ μΌμ체λ‘, 격μ ꡬ쑰 ν¬κΈ°κ° μΈμ μ΄μ¨ ν¬κΈ°μ μ μ¬νμ¬ μ νμ μΌλ‘ μΈμμ μ κ±°νλλ° ν¨κ³Όμ μ΄λ€. μΈ΅μμ΄μ€μμ°νλ¬Όμ 2κ°μ κΈμ μμ΄μ¨μ΄ μμ°κΈ°μ μν΄ λλ¬μΈμ¬ μλ ν면체 ννμ ꡬ쑰λ₯Ό κ°μ§κ³ μμΌλ©°, κ·Έ μ€ μΌλΆλ 3κ° μμ΄μ¨μΌλ‘ μΉνλμ΄ μμ νλ₯Ό λ λ μΈ΅μ ꡬ쑰λ₯Ό κ°μ§λ€. λ μμ ν μΈ΅μ ꡬ쑰 μ¬μ΄μ μ νκ· νμ λ§μΆκΈ° μν΄ μμ΄μ¨κ³Ό λ¬Ό λΆμκ° μ½μ
λμ΄ μ‘΄μ¬νλ©°, μ΄ μμ΄μ¨μ λ€λ₯Έ μμ΄μ¨κ³Ό μ΄μ¨κ΅νμ΄ κ°λ₯νμ¬ μμ€λλ₯Ό μ κ±°νλλ° ν¨κ³Όμ μ΄λ€. λ³Έ μ°κ΅¬λ μ΄μ μ κ°λ°λμ§ μμ λ°©μ¬μ± νμ‘ λ΄μ 곡쑴νλ μμ΄μ¨ μΈμκ³Ό μμ΄μ¨ μμ€λλ₯Ό λμμ ν¨κ³Όμ μΌλ‘ μ κ±°ν μ μλ νλ¬μμ λΈλ£¨λ‘ κ°λν μΈ΅μμ΄μ€μμ°νλ¬Ό(PB-LDH)λ₯Ό κ°λ°νμλ€. ν©μ±λ PB-LDHλ μμ€μ νμ , νΈλ¦¬μ λ³ν μ μΈμ λΆκ΄ν, μ ν μ μ λ° μ£Όμ¬/ν¬κ³Ό μ μ νλ―Έκ²½μ ν΅ν΄ 물리ννμ νΉμ± λΆμμ μ§ννμλ€. κ·Έ κ²°κ³Ό PB-LDH ν©μ± κ³Όμ μ€, Fe(CN)64-λ μΈ΅μμ΄μ€μμ°νλ¬Ό μΈ΅κ°μ μ½μ
λμ§ μκ³ , λ°λ°λ₯΄λ°μ€ νμ μνμ¬ μΈ΅μμ΄μ€μμ°νλ¬Ό νλ©΄μ μμ§λμ΄ μΈ΅μμ΄μ€μμ°νλ¬Ό νλ©΄μ Co-Fe νλ¬μμλΈλ£¨λ₯Ό νμ±νμλ€. PB-LDHν©μ± ν ꡬ쑰μ μμ μ±μ΄ μ¦κ°νμ¬ μ©ν΄λλ Co, Cr, Fe κΈμ μ΄μ¨μ΄ νμ°νκ² μ€μ΄λ κ²μ νμΈ ν μ μμλ€. ν©μ±λ PB-LDHλ₯Ό μ΄μ©νμ¬ ν‘μ°© μ€νμ μ§νν κ²°κ³Ό, 5 mg/Lμ Cs+κ³Ό 5 mg/Lμ IO3βκ° νΌν©λμ΄ μλ μ©μ‘ λ΄μμ 99.7 % μΈμκ³Ό 89.8 %μ μμ€λλ₯Ό μ κ±°νμλ€. PB-LDHμ μΈμ μ κ±° λ₯λ ₯μ 32.36 mg/g, μμ€λ μ κ±° λ₯λ ₯μ 85.47 mg/gμΌλ‘ λμ μ κ±°λμ 보μλ€. pHμ λ°λ₯Έ ν‘μ°© μ€ν κ²°κ³Ό PB-LDHμ μ΅μ νλ pH 쑰건μ 4~10μΌλ‘ λ€μν νκ²½ 쑰건μμ PB-LDHκ° μ¬μ©λ μ μμμ νμΈνμλ€. κ²½μ μ΄μ¨μ΄ μ‘΄μ¬νλ νκ²½μμμ ν‘μ°© μ€ν κ²°κ³Ό, Cs+ μ κ±°λμ λΉμ·ν μ΄μ¨ μ¬μ΄μ¦λ₯Ό κ°μ§ K+μ΄μ¨μ΄ μ‘΄μ¬νλ νκ²½μμ ν‘μ°©λμ΄ μ½κ° κ°μνμμ§λ§, λ€λ₯Έ κ²½μ μμ΄μ¨μμλ ν° λ³νκ° μμλ€. νμ§λ§ IO3βμ μ κ±°λ κ²½μ° λ€λ₯Έ κ²½μ μμ΄μ¨μ΄ μ‘΄μ¬νλ νκ²½μμ ν¬κ² κ°μνμλ€. νΉν μΈ΅μμ΄μ€μμ°νλ¬Όμ μμ΄μ¨ μ νμ±μ΄ λμ SO42βμμ μ κ±°λμ΄ κΈκ²©νκ² κ°μνμλ€. Cs+κ³Ό IO3β ν‘μ°© μ /ν μμ€μ κ΄μ μ λΆκ΄ λΆμ κ²°κ³Ό Co2+κ° Co3+λ‘ μ°νλλ©΄μ, IO3βκ° I2λ‘ Fe3+κ° Fe2+λ‘ νμλμλ€. νμλ Fe2+μ Cs+κ³Ό λ°μνμ¬ μλ‘μ΄ νν©λ¬Ό Cs4Co4Fe3(CN)18μ νμ±νμ¬ Csμ μ κ±°νλ κ²μ μ μ μμλ€. IO3βλ μ£Όλ‘ μΈ΅μμ΄μ€μμ°νλ¬Ό μΈ΅κ°μ μ½μ
λμ΄ μλ Clβμ μ΄μ¨κ΅ννμ¬ μ κ±°λμλ€.Radioactive cesium and iodine have become an emerging issue because theses radionuclide have high radiotoxicity and solubility, and they can easily transport to the environmental. Prussian blue (PB), known as metal hexacyanoferrate compounds, has cubic face centered structure in which lattice size is similar to the ionic size of Cs+. In addition, Layered double hydroxides (LDHs) are composed of the positive charged layer with the exchangeable anions to maintain the structural charge balance. LDHs have anion exchange properties and become the promising sorbents of iodine. Based on the advantages of PB and LDHs, Prussian blue functionalized layered double hydroxides (PB-LDH) were synthesized to remove both Cs+ and IO3β from radioactive solutions concurrently. The PB formation on LDHs was confirmed by X-ray diffraction, Fourier transform infrared, zeta potential, and scanning electron microscopy. During the synthesis PB-LDH, Fe(CN)64β does not intercalate into the LDH layered structure, but aggregates on the LDHs surface according to attractive van der Waals forces and forms PB on the surface of LDHs. Synthesized PB-LDH simultaneously removed 32.36 mg/g of Cs+ and 85.47 mg/g IO3β from the mixed waste solutions. The optimized pH conditions ranged from 4 to 10, so the PB-LDH can be used in various environmental conditions. The Cs+ removal was not significantly changed by competition with other cations, but IO3β removal declined in the presence of other anions, especially in SO42β. The mechanisms of Cs+ were the K+ ion exchange and Fe3+ reduction to form Cs4Co4Fe3(CN)18. Reduction of Fe3+ to Fe2+ promoted the Cs+ intercalation into a body-centered cubic location. In addition, IO3β was removed by ion exchange with intercalated Clβ and by a redox effect with Co ions. This PB-LDH sorbent can be used to remove both radioactive cesium and iodine from the waste solution at the same time
Formation Behaviors of Inter-Metallic Compounds in Al/Mg Hybrid Plates Fabricated by Twin Roll Casting
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Al-Mg-Si ν©κΈμ μμ° μ¨λ λ° μν¨ κ³Όμ μ λ°λ₯Έ λ―ΈμΈκ΅¬μ‘° μ°¨μ΄ λΆμ
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