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A Van der Waals Optoelectronic Synapse with Tunable Positive and Negative Post-Synaptic Current for Highly Accurate Spiking Neural Networks
No full textSpiking neural networks (SNNs) represent a promising computing architecture for neuromorphic hardware, as they process and store information through spike signals, closely mimicking the way the human brain operates. However, most synaptic devices recently proposed for hardware SNN implementations are limited to exhibiting analogue tuning within a single conductance polarity, making them inadequate for realizing scalable and energy-efficient neuromorphic systems. In this study, an optoelectronic synaptic device based on a ReS /WSe /h-BN heterostructure, enabling conductance 22 modulation across both positive and negative states within a single device is demonstrated. This bidirectional plasticity originates from electrostatic modulation of the WSe2 Fermi level, induced by voltage pulses applied through an O2 plasma-treated h-BN weight-control layer. The device exhibits reversible photocurrent polarity, reliable potentiation/depression of the postsynaptic current, and stable synaptic weight retention with reproducible multi-cycle operation. System-level simulations using a 1024–20–3 SNN architecture confirmed the functional advantage of a bidirectional synapse, with networks achieving over 95% facial recognition accuracy within 20 training epochs, whereas the unidirectional synapse-based network plateaued below 75%. These findings highlight the potential of optoelectronic synaptic device with bidirectional plasticity as a promising device platform for efficient on-chip learning in next-generation neuromorphic hardware system.TRUEsciescopu
Structure Degradation Inhibition of Silicon Anode in Lithium Batteries Using a Supramolecular Self- Healing Binder: An In-situ TEM Study
No full textLithium-ion batteries (LIBs) represent a pivotal energy storage technology in modern society, including electronic devices to electric vehicles (EVs) and energy storage systems. The rapid growth of the EV market has intensified the demand for enhanced electrochemical performance and structural stability of LIBs. Current LIB technology for EVs faces fundamental challenges in energy density, power density, and cycle life. In particular, the structural deterioration of the electrode during the cycling process remains a major cause of battery performance degradation. Real-time observation and analysis of this structural degradation phenomenon have emerged as an important task for improving battery performance. While conventional analytical methods such as X-ray diffraction, electron microscopy analysis, and electrochemical performance analysis provide valuable insights into battery performance evaluation, they have limitations in directly elucidating dynamic structural changes and interfacial reaction mechanisms during cycling processes. To overcome these issues, in-situ transmission electron microscopy (in-situ TEM) has garnered significant attention. In-situ TEM serves as a powerful analytical tool capable of directly observing dynamic changes in electrode structure at the nanoscale, particularly enabling real-time atomic-level tracking of solid electrolyte interphase (SEI) layer formation, and growth, cathode electrolyte interphase (CEI) layer dynamics, and crystallographic evolution of electrode active materials. Furthermore, it enables real-time observation of microcrack formation and propagation in electrode structures during lithium ion insertion/extraction, as well as chemical composition changes in interfacial layers due to side reactions at electrode/electrolyte interfaces. These nanoscale real-time observations provide information for elucidating battery degradation mechanisms and developing strategies for their resolution. In this study, I developed supramolecular binders with superior self-healing properties and evaluated their impact on electrode stability using in-situ transmission electron microscopy (TEM). Self-healing binders play a crucial role in preventing electrode failure and maintaining battery performance through stable interfacial properties and excellent adhesion to current collectors. Therefore, understanding how the chemical and physical properties of functional groups contribute to enhanced electrode stability is essential for designing supramolecular self-healing binders. The designed supramolecular self-healing binder comprised poly(acrylic acid) and poly(4- vinylpyridine-naphthalene) block copolymers. The poly(acrylic acid) was designed to exhibit strong binding with active materials through hydrogen bonding, while poly(4-vinylpyridine- naphthalene) was designed with naphthalene as a guest scaffold to form robust bonds with the host molecule Cucurbit-[n]-urils. When employed as a binder for silicon (Si) anodes, these self-healing binders formed 3-dimensional network structures through host-stabilized charge transfer (HSCT)- based intermolecular host-guest interaction supramolecular crosslinking, demonstrating high electrode stability based on excellent self-healing properties even under external physical damage. Using in-situ TEM, I observed the volume changes of Si materials and the self-healing process of the binder at the nanoscale during the charge/discharge process. Qualitative and quantitative assessments revealed significantly reduced structural degradation in the developed self-healing binder compared to commercial binders. I elucidated the operational mechanism of the supramolecular self-healing binder in Si electrodes. Consequently, this study evaluated the functionality of self-healing binders through nanoscale analysis using in-situ TEM and proposed novel material design strategies for developing high-performance binders for next-generation LIBs. In particular, real-time observations during charge/discharge processes presented a new paradigm for binder design focused on enhancing interfacial stability. This research is expected to play a crucial role in the development of high-performance energy storage systems in the future.|리튬이온 배터리는 전자기기, 전기자동차, ESS 등 현대 사회에서 핵심적인 에너지 저장 기술이다. 전기자동차 시장의 급속한 성장에 따라 리튬이온 배터리의 전기화학적 성능 및 구조적 안정성 향상에 대한 기술적 요구가 증대되고 있다. 현재 전기자동차용 리튬이온 배터리 기술은 에너지 밀도, 출력 밀도, 수명주기 측면에서 근본적인 기술적 한계에 직면해 있다. 특히 반복된 충/방전 과정에서 발생하는 전극 구조의 구조적 열화 현상은 배터리 성능 저하의 핵심적인 원인이다. 이러한 구조적 열화 현상을 실시간으로 관찰하고 분석하는 것은 배터리 성능 향상을 위한 핵심 과제로 대두되고 있다. 기존의 X-선 회절 분석, 전자현미경을 이용한 모폴로지 분석, 그리고 전기화학 분석 등은 배터리 성능을 평가하는 데 유용한 정보를 제공하지만, 충/방전 과정에서 발생하는 동적인 구조 변화와 계면 반응 메커니즘을 직접적으로 규명하는 데는 한계가 있다. 이러한 한계를 극복하기 위해 실시간 투과전자현미경(in-situ TEM)이 주목받고 있다. 실시간 투과전자현미경은 나노 스케일에서 전극 구조의 동적 변화를 직접적으로 관찰할 수 있는 강력한 분석 도구로, 특히 충/방전 과정에서 형성되는 고체 전해질 계면층(SEI layer)의 생성 및 성장 과정, 전해질과 전극 계면에서 형성되는 양극 전해질 계면층(CEI layer)의 동적 변화, 그리고 전극 활물질의 결정구조 변화를 원자 수준에서 실시간으로 추적할 수 있다. 또한, 리튬 이온의 삽입/탈리 과정에서 발생하는 전극 구조의 미세균열 형성과 전파 과정, 전극/전해질 계면에서의 부반응으로 인한 계면층의 화학적 조성 변화까지 실시간으로 관찰이 가능하다. 이러한 나노 스케일에서의 실시간 관찰은 배터리의 성능 저하 메커니즘을 규명하고, 이를 해결하기 위한 새로운 전략을 수립하는 데 필수적인 정보를 제공한다. 본 연구에서 우수한 자가 치유 특성을 지닌 초분자 바인더 개발하고 실시간 투과전자현미경을 활용하여 전극 안정성에 미치는 영향을 평가하였다.자가 치유 바인더는 안정적인 계면 특성 및 집전체와의 우수한 접착 특성으로 전극 손상을 방지하고 배터리 수명을 유지시키는 중요한 역할을 한다. 따라서, 초분자 자가치유 바인더를 설계하기 위해서는 관능기의 화학적/물리적 특성이 전극의 안정성 향상에 미치는 영향을 이해하는 것이 필수적이다. 설계된 초분자 자가 치유 바인더는 폴리아크릴산과 폴리비닐피리딘-나프탈렌 블록고분자로 구성하였다. 폴리아크릴산 고분자는 수소결합을 통해 전극 활물질과 높은 결합력을 보일 수 있도록, 폴리비닐피리딘-나프탈렌은 주인분자인 Cucurbutril(커커비트릴)과 강력한 초분자 결합을 가질 수 있도록 손님 분자인 나프탈렌을 도입하여 설계 하었다. 이러한 고분자는 실리콘 음극제의 바인더로써 주인분자 도입 시에 주인 안정화 전하 이동 (HSCT, Host-Stabilized Charge Transfer)에 기반한 분자간 주인-손님 상호작용 초분자 가교결합을 통해 삼차원 네트워크 구조를 형성하였으며, 외부의 물리적 손상에 의해서도 우수한 자가치유에 기반하여 높은 전극 안정성을 보였다. 실시간 투과전자현미경을 통해 충/방전 과정에서 발생하는 전극 활물질의 부피 변화와 바인더의 자가치유 과정을 나노크기 수준에서 관찰했다. 시판되는 바인더 대비 개발된 자가 치유 바인더는 충방전 시에 구조적 열화가 현저하게 적게 나타남을 정성 및 정량평가 할 수 있었다. 실리콘 음극제 기반 초분자 자가치유 바인더의 구동 메커니즘을 규명하였다. 결과적으로, 본 연구는 실시간 투과전자현미경을 활용한 나노 스케일 분석을 통해 자가치유 바인더의 기능성을 평가하고, 이를 바탕으로 차세대 리튬이온 배터리용 고성능 바인더 개발을 위한 새로운 소재 설계 전략을 제시하였다. 특히 충/방전 과정에서 발생하는 실시간 관찰 결과는 계면 안정성 향상을 위한 바인더 설계의 새로운 패러다임을 제시하였다. 향후 고성능 에너지 저장 시스템 개발에 핵심적인 역할을 할 것으로 기대된다.MasterAbstract
국문요약
1. Introduction 16
1.1. LIBs technology and requirements for next-generation LIBs 16
1.2. In-situ TEM analysis for a battery 18
1.3. Silicon electrodes for next-generation LIBs 20
1.4. Strategies for utilizing Si materials in electrodes 22
1.5. Motivation. 24
2. Experimental sections 26
2.1. Materials and instruments 26
2.2. Synthesis of compounds used in this study 27
2.2.1 Synthesis of 4VP-Nap 27
2.2.2 Synthesis of PAA/P4VP-Nap 27
2.3. Sample preparation 28
2.3.1. Host-guest complexation of a H-GB-self-healing gel 28
2.4. Characterization of a H-GB-self-healing gel 28
2.4.1. Fourier transform-infrared (FT-IR) spectroscopy 28
2.4.2. Nuclear magnetic resonance (NMR) spectroscopy 29
2.4.3. Universal testing machine (UTM) 29
2.4.4. Self-healing property test 29
2.4.5. Thermo-gravimetry analysis (TGA) 29
2.4.6. Differential scanning calorimetry (DSC) 30
2.5. Characterization of the Si electrode 30
2.5.1. Peeling force test 30
2.5.2. Folding test 30
2.5.3. Atomic force microscopy (AFM) 30
2.5.4. Scanning electron microscopy (SEM) 31
2.6. Preparation of Si electrodes 32
2.6.1. Preparation of Si electrodes and coin-cell assembly 32
2.6.1. Electrochemical characterization 32
2.7. Analysis of Si swelling behavior for self-healing mechanism 33
2.7.1. Fabrication of graphene-coated grids 33
2.7.2. Graphene liquid cell with an encapsulated Si NPs-solution using grid-sandwich
method 33
2.7.3. In-situ TEM imaging to reveal the Si swelling behavior 34
3. Results and discussion 35
3.1. Synthesis and characterization of guest scaffolds 35
3.2. Characterization of host-guest complexations for a self-healing gel 39
3.3. Mechanical property and self-healing property of supramolecular self-healing binders
. 41
3.4. Characterization of supramolecular self-healing binder-based Si electrodes 43
3.5. Electrochemical performance analysis of self-healing binder-based electrodes 45
3.6. Structural stability of a self-healing binder: surface roughness analysis via AFM 47
3.7. Structural stability of a self-healing binder: surface morphology analysis via SEM . 49
3.8. Fabrication of graphene liquid cell and encapsulation for observing Si swelling
mechanism using in-situ TEM 51
4. Conclusions 54
5. References 55
List of Scheme
Scheme 1. Schematic illustration of the self-healing mechanism of a self-healing binder-
based Si electrode. 25
List of Table
Scheme 1. Association constant (Ka) values for host (H) and guest (G) molecules. 3
Pre-AttentiveGaze: gaze-based authentication dataset with momentary visual interactions
No full textThis manuscript presents a Pre-AttentiveGaze dataset. One of the defining characteristics of gaze-based authentication is the necessity for a rapid response. In this study, we constructed a dataset for identifying individuals through eye movements by inducing "pre-attentive processing" in response to a given gaze stimulus in a very short time. A total of 76,840 eye movement samples were collected from 34 participants across five sessions. From the dataset, we extracted the gaze features proposed in previous studies, pre-processed them, and validated the dataset by applying machine learning models. This study demonstrates the efficacy of the dataset and illustrates its potential for use in gaze-based authentication of visual stimuli that elicit pre-attentive processing.TRUEsciescopu
Harnessing nutrients and natural products for sustainable drug development against aging
No full textDeveloping treatments for age-related diseases requires cost-effective and efficient approaches. Nutrients and natural metabolites offer safer alternatives to synthetic drugs. Aging increases the need for solutions that protect health and repair cells. Recent studies show that nutrients and natural products reduce oxidative stress, regulate metabolism, and influence longevity-related genes. This review focuses on vitamins, minerals, antioxidants, and natural products that improve healthspan and combat aging. It also discusses challenges such as standardization, clinical validation, and regulatory approval. Finally, emerging trends, such as personalized nutrition and advanced delivery systems, highlight the potential of these metabolites for addressing aging.TRUEsciescopu
Fabrication of Graphene Oxide/Polyacrylonitrile Electrospun Nanofiber Membrane with a Carbon Nanotube Photothermal Layer for Solar-Driven Interfacial Water Evaporation Kateryne Rocio Ccama Mamani School of Environment and Energy Engineering Gwangju Institute of Science and Technology
No full textWater scarcity is a global issue that has been worsening in recent years. Due to the limited access to and depletion of natural freshwater sources, such as rivers and groundwater, desalination processes have emerged a crucial solution to address the insufficient water supply problem. However, a major environmental impact of this technology is the production of brine, a highly concentrated salt solution with significant ecological risks. To mitigate the impact of brine disposal, the Zero-Liquid Discharge (ZLD) concept recovers water and valuable resources like salts, preventing harmful environmental discharges. To reduce reliance on energy-intensive processes, the combination of solar-driven interfacial evaporation technology, a technology that harnesses sunlight to generate heat promoting water evaporation, with ZLD system, offers a sustainable alternative, minimizing environmental impact and improving brine management. In this research, a polyacrylonitrile (PAN) solution is combined with graphene oxide (GO) particles to fabricate an electrospun nanofiber membrane using electrospinning technique. Carbon nanotube (CNT) particles were subsequently incorporated onto the membrane via spraying, forming a uniform photothermal layer. Membranes are prepared with various graphene oxide concentrations (0.5 - 4 % relative to PAN wt%) and CNT spraying durations (30 - 120 seconds). The performance of these membranes was then evaluated in a solar-driven interfacial water evaporation process. The optimal conditions for the CNT-GO/PAN (CGOP) membranes were a 2% GO concentration and a CNT spraying of 90 seconds. Under these conditions, the membrane achieved an evaporation rate of 1.53 kg m-2 h-1, compared to 1.22 kg m-2 h- for the GO/PAN (GOP) and 0.89 kg m-2 h-1 for the pure PAN membrane. Testing the optimal membrane with simulated saline water (3.5 wt% NaCl) and brine (7 wt% NaCl) revealed a ~33% performance reduction for both cases. Despite this, the membrane demonstrated the ability to work under high salinity conditions and tolerance to salt crystal accumulation, highlighting its photothermal conversion potential for solar-driven evaporation applications, such as Zero-Liquid Discharge.MasterABSTRACT i
Table of Contents ii
List of Tables iv
List of Figures iv
1. Introduction 1
1.1. Background 1
1.2. Hypothesis 3
1.3. Objectives 3
2. Literature Review 4
2.1. Water scarcity 4
2.2. Zero-Liquid Discharge concept. 4
2.3. Solar-Thermal Technologies 5
2.3.1. Solar-Driven Evaporation 5
2.3.2. Solar Interfacial Evaporation 7
2.4. Electrospinning Technique 10
2.4.1. Concept 10
2.4.2. Principle of Electrospinning 10
2.4.3. Application of Electrospun Nanofiber for Solar-Driven Interfacial Evaporation 11
2.5. Carbon Nanotubes Photothermal Conversion Mechanism 12
2.6. Graphene oxide particles and water transport 13
3. Experimental section 14
3.1. Materials 14
3.2. Fabrication of Hydrophilic-Hydrophobic Dual Membrane. 14
3.2.1. Preparation of GO/PAN Nanofiber Membrane 14
3.2.2. Preparation of Photothermal Layer 15
3.2.3. Preparation of CNT-GO/PAN Evaporation Module 16
3.3. Characterization 17
3.3.1. Morphology 17
3.3.2. Attenuated Total Reflectance – Fourier Transform Infrared Spectroscopy 18
3.3.3. Water Contact Angle 18
3.3.4. UV-vis-NIR Spectrophotometry 18
3.4. Performance Tests (Solar Interfacial Evaporation Experiments) 18
3.4.1. Steam Generation Test 18
3.4.2. Desalting Experiment 19
3.4.3. Analysis Methods for Solar Steam Generation Efficiency 19
4. Results and Discussion 20
4.1. Multiwalled-CNT and GO Commercial Powder Characterization 20
4.1.1. Morphological and Optical Properties 20
4.2. PAN Surface Morphology 21
4.3. Morphologies and Properties of CNT-GO/PAN Membrane 22
4.3.1. Hydrophilic GO/PAN Nanofiber Membrane 22
4.3.2. CNT GO/PAN Nanofiber Membrane 27
4.4. CNT-GO/PAN Membrane and their Photothermal Conversion Properties 33
4.4.1. Photothermal Conversion Capability 33
4.4.2. Infrared Thermal Image Analysis 34
4.5. Desalination Performance 37
5. Summary and conclusions 39
6. References 40
7. Acknowledgments. 4
Synthesis and Structure-Activity Relationship Studies of Capsid Assembly Modulators Targeting Hepatitis B Virus
No full textHepatitis B is difficult to be cured completely and is facing many difficulties in developing treatments. Currently using antiviral treatments can only inhibit the proliferation of viruses if it is taken continuously or have serious immune side effects. In this situation, Capsid Assembly Modulators (CAMs)are emerging as a new antiviral agent. Unlike other drugs, the CAM inhibits the core protein of the virus, preventing capsid formation and ultimately acting as this mechanism to prevent virus proliferation. Previous studies have reported that it has strong antiviral effects as CAMs and some compounds entered into clinical trials. Based on those studies, pyrimidine and pyridine core derivatives were synthesized and their inhibitory effects to viral DNA were evaluated through in vitro screening. At in vitro screening, compounds 18c showed inhibitory EC50 value at 0.085 μM and 30f approximately at 1 μM, especially 30f showed low toxicity and high bioavailability at oral administration.MasterABSTRACT i
CONTENTS ii
LIST OF FIGURES, SCHEMES, AND TABLES xi
Ⅰ. INTRODUCTION 1
Ⅱ. MATERIALS AND METHODS 5
2.1. Materials 5
2.1.1 Abbreviations 5
2.2. Chemistry 5
2.2.1. Synthesis of LDD-3677 derivatives. 5
2.2.1.1 General procedure for synthesis of compound (1) 5
2.2.1.2. N4-(3-chloro-4-fluorophenyl)-N6-cyclopentyl-2-(methylthio)pyrimidine-4,6-diamine (2a) · 6
2.2.1.3.tert-butyl(S)-3-((6-((3-chloro-4-fluorophenyl)amino)-2-(methylthio)pyrimidin-4-
yl)amino)pyrrolidine-1-carboxylate (3a) 6
2.2.1.4.tert-butyl(R)-3-((6-((3-chloro-4-fluorophenyl)amino)-2-(methylthio)pyrimidin-4-
yl)amino)pyrrolidine-1-carboxylate (4a) 6
2.2.1.5. N4-benzyl-N6-(3-chloro-4-fluorophenyl)-2-(methylthio)pyrimidine-4,6-diamine (5a) 7
2.2.1.6. N4-(3-chloro-4-fluorophenyl)-2-(methylthio)-N6-phenethylpyrimidine-4,6-diamine (6a) 7
2.2.1.7. N-(3-chloro-4-fluorophenyl)-2-(methylthio)-6-(pyrrolidin-1-yl)pyrimidin-4-amine (7a) ·· ·· 8
2.2.1.8. N4-(3-chloro-4-fluorophenyl)-2-(methylthio)-N6-(oxazol-2-yl)pyrimidine-4,6-diamine (8a) 8
2.2.1.9. N4-(3-chloro-4-fluorophenyl)-2-(methylthio)-N6-(1,2,4-thiadiazol-5-yl)pyrimidine-4,6-
diamine (9a) 8
2.2.1.10. N4-(3-chloro-4-fluorophenyl)-N6-cyclopentyl-2-(methylsulfonyl)pyrimidine-4,6-diamine
(2b) 9
2.2.1.11.tert-butyl(S)-3-((6-((3-chloro-4-fluorophenyl)amino)-2-(methylsulfonyl)pyrimidin-4-
yl)amino)pyrrolidine-1-carboxylate (3b) 9
2.2.1. 12.tert-butyl(R)-3-((6-((3-chloro-4-fluorophenyl)amino)-2-(methylsulfonyl)pyrimidin-4-
yl)amino)pyrrolidine-1-carboxylate (4b) 9
2.2.1.13. (S)-N4-(3-chloro-4-fluorophenyl)-2-(methylsulfonyl)-N6-(pyrrolidin-3-yl)pyrimidine-4,6-
diamine(3c) 10
2.2.1.14.(R)-N4-(3-chloro-4-fluorophenyl)-2-(methylsulfonyl)-N6-(pyrrolidin-3-yl)pyrimidine-4,6-
diamine (4c) 10
2.2.1.15. N4-benzyl-N6-(3-chloro-4-fluorophenyl)-2-(methylsulfonyl)pyrimidine-4,6-diamine (5b) 10
2.2.1.16. N-(3-chloro-4-fluorophenyl)-2-(methylsulfonyl)-6-(pyrrolidin-1-yl)pyrimidin-4-amine (6b)
11
2.2.1.17. N4-(3-chloro-4-fluorophenyl)-2-(methylsulfonyl)-N6-phenethylpyrimidine-4,6-diamine (7b)
11
2.2.1.18. N4-(3-chloro-4-fluorophenyl)-2-(methylsulfonyl)-N6-(oxazol-2-yl)pyrimidine-4,6-diamine
(8b) 11
2.2.1.19. N4-(3-chloro-4-fluorophenyl)-2-(methylsulfonyl)-N6-(1,2,4-thiadiazol-5-yl)pyrimidine-4,6-
diamine (9b) 11
2.2.2. Synthesis of Aminothiadiazol derivatives 11
2.2.2.1. 6-chloro-2-(methylthio)-N-(3,4,5-trifluorobenzyl)pyrimidin-4-amine (10a) 11
2.2.2.2. (S)-(-)-6-chloro-2-(methylthio)-N-(1-(3,4,5-trifluorophenyl)ethyl)pyrimidin-4-amine(11a)
· 12
2.2.2.3. (R)-(+)-6-chloro-2-(methylthio)-N-(1-(3,4,5-trifluorophenyl)ethyl)pyrimidin-4-amine(12a)
12
2.2.2.3. 6-chloro-N-(4-fluoro-3-(trifluoromethyl)benzyl)-2-(methylthio)pyrimidin-4-amine (13a) · 13
2.2.2.4. 6-chloro-N-(4-fluoro-3-methylbenzyl)-2-(methylthio)pyrimidin-4-amine (14a) 13
2.2.2.5. 5-(((6-chloro-2-(methylthio)pyrimidin-4-yl)amino)methyl)-2-fluorobenzonitrile (15a) 13
2.2.2.7. 6-chloro-2-(methylthio)-N-(3,4,5-trifluorophenyl)pyrimidin-4-amine (16a) 14
2.2.2.8. 6-chloro-N-(4-fluoro-3-(trifluoromethyl)phenyl)-2-(methylthio)pyrimidin-4-amine (17a) · 14
2.2.2.9. 6-chloro-N-(4-fluoro-3-methylphenyl)-2-(methylthio)pyrimidin-4-amine (18a) 14
2.2.2.10. 5-((6-chloro-2-(methylthio)pyrimidin-4-yl)amino)-2-fluorobenzonitrile (19a) 15
2.2.2.11. 6-chloro-N-(3,4-difluorophenyl)-2-(methylthio)pyrimidin-4-amine (20a) 15
2.2.2.12. 2-(methylthio)-N4-(1,2,4-thiadiazol-5-yl)-N6-(3,4,5-trifluorobenzyl)pyrimidine-4,6-diamine
(10b) 15
2.2.2.13. (S)-(-)-2-(methylthio)-N4-(1,2,4-thiadiazol-5-yl)-N6-(1-(3,4,5-
trifluorophenyl)ethyl)pyrimidine-4,6-diamine (11b) 16
2.2.2.14. (R)-(+)-2-(methylthio)-N4-(1,2,4-thiadiazol-5-yl)-N6-(1-(3,4,5-
trifluorophenyl)ethyl)pyrimidine-4,6-diamine (12b) 16
2.2.2.15. N4-(4-fluoro-3-(trifluoromethyl)benzyl)-2-(methylthio)-N6-(1,2,4-thiadiazol-5-
yl)pyrimidine-4,6-diamine (13b) 16
2.2.2.16. N4-(4-fluoro-3-methylbenzyl)-2-(methylthio)-N6-(1,2,4-thiadiazol-5-yl)pyrimidine-4,6-
diamine (14b) 17
2.2.2.17.5-(((6-((1,2,4-thiadiazol-5-yl)amino)-2-(methylthio)pyrimidin-4-yl)amino)methyl)-2-
fluorobenzonitrile (15b) 17
2.2.2.18. 2-(methylthio)-N4-(1,2,4-thiadiazol-5-yl)-N6-(3,4,5-trifluorophenyl)pyrimidine-4,6-diamine
(16b) 17
2.2.2.19. N4-(4-fluoro-3-methylphenyl)-2-(methylthio)-N6-(1,2,4-thiadiazol-5-yl)pyrimidine-4,6-
diamine (17b) 17
2.2.2.20. N4-(4-fluoro-3-methylphenyl)-2-(methylthio)-N6-(1,2,4-thiadiazol-5-yl)pyrimidine-4,6-
diamine (18b) 17
2.2.2.21. N4-(4-fluoro-3-methylphenyl)-2-(methylthio)-N6-(1,2,4-thiadiazol-5-yl)pyrimidine-4,6-
diamine (19b) 18
2.2.2.22. N4-(3,4-difluorophenyl)-2-(methylthio)-N6-(1,2,4-thiadiazol-5-yl)pyrimidine-4,6-diamine
(20b) 18
2.2.2.23. 2-(methylsulfonyl)-N4-(1,2,4-thiadiazol-5-yl)-N6-(3,4,5-trifluorobenzyl)pyrimidine-4,6-
diamine (10c) 18
2.2.2.24. (S)-(-)-2-(methylsulfonyl)-N4-(1,2,4-thiadiazol-5-yl)-N6-(1-(3,4,5-
trifluorophenyl)ethyl)pyrimidine-4,6-diamine (11c) 18
2.2.2.25. (R)-(+)-2-(methylsulfonyl)-N4-(1,2,4-thiadiazol-5-yl)-N6-(1-(3,4,5-
trifluorophenyl)ethyl)pyrimidine-4,6-diamine (12c) 19
2.2.2.26. N4-(4-fluoro-3-(trifluoromethyl)benzyl)-2-(methylsulfonyl)-N6-(1,2,4-thiadiazol-5-
yl)pyrimidine-4,6-diamine. (13c) 19
2.2.2.27. N4-(4-fluoro-3-methylbenzyl)-2-(methylsulfonyl)-N6-(1,2,4-thiadiazol-5-yl)pyrimidine-4,6-
diamine (14c) 19
2.2.2.28. 5-(((6-((1,2,4-thiadiazol-5-yl)amino)-2-(methylsulfonyl)pyrimidin-4-yl)amino)methyl)-2-
fluorobenzonitrile (15c) 19
2.2.2.29. 2-(methylsulfonyl)-N4-(1,2,4-thiadiazol-5-yl)-N6-(3,4,5-trifluorophenyl)pyrimidine-4,6-
diamine (16c) 20
2.2.2.30. N4-(4-fluoro-3-(trifluoromethyl)phenyl)-2-(methylsulfonyl)-N6-(1,2,4-thiadiazol-5-
yl)pyrimidine-4,6-diamine (17c) 20
2.2.2.31. N4-(4-fluoro-3-methylphenyl)-2-(methylsulfonyl)-N6-(1,2,4-thiadiazol-5-yl)pyrimidine-4,6-
diamine (18c) 20
2.2.2.32. 5-((6-((1,2,4-thiadiazol-5-yl)amino)-2-(methylsulfonyl)pyrimidin-4-yl)amino)-2-
fluorobenzonitrile (19c) 20
2.2.2.33. N4-(3,4-difluorophenyl)-2-(methylsulfonyl)-N6-(1,2,4-thiadiazol-5-yl)pyrimidine-4,6-
diamine (20c) 21
2.2.3. Synthesis of Alkylsulfonyl derivatives, Pyrimidine core 21
2.2.3.1. 2-(((tetrahydro-2H-pyran-4-yl)methyl)thio)pyrimidine-4,6-diol (21a) 21
2.2.3.2. 4,6-dichloro-2-(((tetrahydro-2H-pyran-4-yl)methyl)thio)pyrimidine (21b) 21
2.2.3.3. 6-chloro-N-(4-fluoro-3-methylphenyl)-2-(((tetrahydro-2H-pyran-4-yl)methyl)thio)pyrimidin-
4-amine (21c) 21
2.2.3.4. N4-(4-fluoro-3-methylphenyl)-2-(((tetrahydro-2H-pyran-4-yl)methyl)thio)-N6-(1,2,4-
thiadiazol-5-yl)pyrimidine-4,6-diamine (21d) 22
2.2.3.5. N4-(4-fluoro-3-methylphenyl)-2-(((tetrahydro-2H-pyran-4-yl)methyl)sulfonyl)-N6-(1,2,4-
thiadiazol-5-yl)pyrimidine-4,6-diamine (21e) 22
2.2.3.6. 2-((4-methoxybenzyl)thio)pyrimidine-4,6-diol (22a) 23
2.2.3.7. 4,6-dichloro-2-((4-methoxybenzyl)thio)pyrimidine (22b) 23
2.2.3.8. 6-chloro-N-(4-fluoro-3-methylphenyl)-2-((4-methoxybenzyl)thio)pyrimidin-4-amine (22c) 23
2.2.3.9. N4-(4-fluoro-3-methylphenyl)-2-((4-methoxybenzyl)thio)-N6-(1,2,4-thiadiazol-5-
yl)pyrimidine-4,6-diamine (22d) 24
2.2.3.10. N4-(4-fluoro-3-methylphenyl)-2-((4-methoxybenzyl)thio)-N6-(1,2,4-thiadiazol-5-
yl)pyrimidine-4,6-diamine (22e) 24
2.2.3.11. 6-chloro-N-(4-fluoro-3-methylphenyl)-2-(((tetrahydro-2H-pyran-4-
yl)methyl)sulfonyl)pyrimidin-4-amine (23e) 24
2.2.3.12. 6-chloro-N-(4-fluoro-3-methylphenyl)-2-((4-methoxybenzyl)sulfonyl)pyrimidin-4-amine
(24e) 24
2.2.4. Synthesis of Alkylsulfonyl derivatives, Pyridine core 25
2.2.4.1. 2-((tetrahydro-2H-pyran-4-yl)thio)isonicotinic acid (25a) 25
2.2.4.2. N-(4-fluoro-3-methylphenyl)-2-((tetrahydro-2H-pyran-4-yl)thio)isonicotinamide (25b) 25
2.2.4.3. N-(4-fluoro-3-methylphenyl)-2-((tetrahydro-2H-pyran-4-yl)sulfonyl)isonicotinamide (25c)
25
2.2.4.4. 2-(((tetrahydro-2H-pyran-4-yl)methyl)thio)isonicotinic acid (26a) 26
2.2.4.5. N-(4-fluoro-3-methylphenyl)-2-(((tetrahydro-2H-pyran-4-yl)methyl)thio)isonicotinamide
(26b) 26
2.2.4.6. N-(4-fluoro-3-methylphenyl)-2-(((tetrahydro-2H-pyran-4-yl)methyl)sulfonyl)isonicotinamide
(26c) 26
2.2.4.7. 2-((((1r,4r)-4-(ethoxycarbonyl)cyclohexyl)methyl)thio)isonicotinic acid (27a) 27
2.2.4.8. ethyl(1r,4r)-4-(((4-((4-fluoro-3-methylphenyl)carbamoyl)pyridin-2-
yl)thio)methyl)cyclohexane-1-carboxylate (27b) 27
viii
2.2.4.9. ethyl(1r,4r)-4-(((4-((4-fluoro-3-methylphenyl)carbamoyl)pyridin-2-
yl)sulfonyl)methyl)cyclohexane-1-carboxylate (27c) 27
2.2.4.10. (1r,4r)-4-(((4-((4-fluoro-3-methylphenyl)carbamoyl)pyridin-2-
yl)sulfonyl)methyl)cyclohexane-1-carboxylic acid (27d) 28
2.2.4.11. 2-((((1r,4r)-4-(dimethylcarbamoyl)cyclohexyl)methyl)sulfonyl)-N-(4-fluoro-3-
methylphenyl)isonicotinamide (27e) 28
2.2.4.12. 2-((((1R,2R)-2-(methoxycarbonyl)cyclohexyl)methyl)thio)isonicotinic acid (28a) 29
2.2.4.13. methyl (1R,2R)-2-(((4-((4-fluoro-3-methylphenyl)carbamoyl)pyridin-2-
yl)thio)methyl)cyclohexane-1-carboxylate (28b) 29
2.2.4.14. methyl (1R,2R)-2-(((4-((4-fluoro-3-methylphenyl)carbamoyl)pyridin- 2
yl)sulfonyl)methyl)cyclohexane-1-carboxylate (28c) 29
2.2.4.15. (1R,2R)-2-(((4-((4-fluoro-3-methylphenyl)carbamoyl)pyridin-2-
yl)sulfonyl)methyl)cyclohexane-1-carboxylic acid (28d) 30
2.2.4.16. 2-((((1R,2R)-2-(dimethylcarbamoyl)cyclohexyl)methyl)sulfonyl)-N-(4-fluoro-3-
methylphenyl)isonicotinamide (28e) 30
2.2.4.17. tert-butyl 4-(((4-((4-fluoro-3-methylphenyl)carbamoyl)pyridin-2-yl)thio)methyl)piperidine-
1-carboxylate (29a) 30
2.2.4.18. tert-butyl 4-(((4-((4-fluoro-3-methylphenyl)carbamoyl)pyridin-2-yl)thio)methyl)piperidine-
1-carboxylate (29b) 31
2.2.4.19. tert-butyl 4-(((4-((4-fluoro-3-methylphenyl)carbamoyl)pyridin-2-
yl)sulfonyl)methyl)piperidine-1-carboxylate (29c) 31
2.2.4.20. N-(4-fluoro-3-methylphenyl)-2-((piperidin-4-ylmethyl)sulfonyl)isonicotinamide (29d) ·· 31
2.2.4.21. N-(4-fluoro-3-methylphenyl)-2-((piperidin-4-ylmethyl)sulfonyl)isonicotinamide (29f) 32
2.2.4.22. 2-(((1-acetylpiperidin-4-yl)methyl)sulfonyl)-N-(4-fluoro-3-methylphenyl)isonicotinamide
(30f) 32
2.3. Biology 33
2.3.1. Cell Culture 33
2.3.2. DNA Prepration and Quantitative PCR for HBV DNA Quantification 33
2.3.3. Metabolic Stability Test in Human and Mouse Liver Microsomes 33
2.3.4. CYP Inhibition assay in Human Liver Microsomes 34
2.3.5. hERG Potassium Channel Patch Clamp assay 34
2.3.6. Mouse in vivo PK 35
2.4. Molecular Docking Study 35
Ⅲ. RESULTS AND DISCUSSION 36
3.1. Synthesis 36
3.2. In vitro assay with Structure Activity-Relationship strategy. 37
3.3 Molecular Docking Study 38
3.4. Metabolic Stability of Compound 30f in Human and Mouse Liver Microsomes 39
3.5. In vitro Toxicological Parameters of Compound 30f in Human Liver Microsomes 39
3.6. Mouse in vivo PK study 40
Ⅳ. CONCLUSION 41
Ⅴ. REFERENCES 50
KOREAN ABSTRACT (국문 초록) 5
Enhanced Myogenic Differentiation of Human Adipose-Derived Stem Cells via Integration of 3D Bioprinting and In Situ Shear-Based Blade Coating
No full textConventional treatments for volumetric muscle loss (VML) encounter limitations, such as donor site constraints and exploration of tissue engineering methods. Here, the fabrication of human adipose stem cell (hASC)-laden cell constructs are proposed using a 3D bioprinting technique supported by blade casting. This process induces mechanotransduction to activate stem cell activities, including proliferation and myogenic differentiation. The printing conditions are optimized by assessing the effects of various process parameters on mechanotransduction signaling pathways. Notably, blade-assisted bioprinting under carefully selected parameters enhanced the in vitro myogenic activity of the fabricated hASC constructs. Moreover, in vivo evaluation in mice with VML defects demonstrate that shear-induced bioconstructs effectively restored lost functionalities and muscle volume compared to those of normally bioprinted cell constructs. The results show the potential of integrating bioprinting with hASC-based therapies to enhance muscle regeneration and functional recovery, offering a meaningful platform for future tissue engineering approaches for VML treatment. © 2024 Wiley-VCH GmbH.FALSEsciescopu
Method for laser cleaning of painted metal scraps to improve classification accuracy during laser-induced breakdown spectroscopy based sorting.
No full text레이저 유도 붕괴 분광법(Laser-induced breakdown spectroscopy, LIBS)은 레이저 조사로 발생하는 플라즈마를 측정하여 정량적 및 정성적 분석을 수행하는 기술입니다. 이 기술은 측정 시간이 매우 짧아 실시간 분석이 가능하며, 공기 중에서도 측정할 수 있고 다중 원소 분석이 가능하여 다양한 산업 연구 분야에서 활발히 연구되고 있습니다. 실제 LIBS기반 장비를 제작하였을 때 깨끗한 폐금속에서는 높은 순도 및 정확도로 재활용의 실현 가능성을확인 하였지만 표면이 오염으로 두껍게 덮인 샘플에서는 분류가 불가능 하였습니다.
이러한 표면 오염 문제를 해결하기 위해 본 연구에서는 대표적인 표면 오염 중 하나인 페인트를 대상으로, 페인트가 LIBS 신호에 주는 영향에 대해서 분석을 하였으며, 분류정확도 향상을 위한 laser cleaning 방법을 제시하였습니다. 대표적인 색상인 검은색 페인트와 흰색 페인트를 알루미늄, 구리, 스테인리스 스틸 3종 금속에 분사 시간을 다르게 하여 도장하여 LIBS 분석하였습니다. 검은색 페인트는 넓은 배경 신호, 목표 금속과 관련 없는 신호 측정, 목표 금속의 약한 신호 등으로 LIBS에 영향을 미쳤습니다. 흰색 페인트는 높은 투과율로 인하여 두께에 상관없이 한번에 laser shot 만으로도 금속표면이 노출되었습니다. LIBS신호는 검은색 페인트와 동일하게 넓은 배경 신호 및 목표 금속과 관련없는 신호들이 측정되었으나, 나노파티클의 효과로 검은페인트와는 다르게 목표 금속에서 강한 신호가 측정되었습니다.
이러한 영향을 줄이기 위해 신호 처리와 analysis shot보다 큰 spot size를 가지는 cleaning shot을 사용하였습니다. 검은색 페인트에서는 표면이 cleaning shot에 의하여 노출되었을 때 analysis shot을 쏘면 높은 분류 정확도를 얻을 수 있었습니다. Cleaning shot과 동시에 LIBS측정 할 때, 전체적으로 강한 신호가 측정되는 위치를 찾음으로써 페인트 두께에 상관없이 정확한 클리닝 샷을 쏠 수 있었습니다. 제안된 방법으로 분류했을 때, no-cleaning shot 조건보다 높은 정확도와 처리량을 얻을 수 있었습니다. 흰색 페인트는 높은 투과성과 나노 입자들에 의한 증폭 덕분에 2개의 laser shot만으로도 높은 분류정확도를 얻을 수 있었으며, cleaning shot을 조사할 필요가 없습니다. 이는 페인트 색상별로 다른 방식으로 LIBS측정을 하는 것이 효율적이라는 것을 확인할 수 있는 결과입니다.
본 연구를 통해 페인트와 같은 두꺼운 표면 오염이 존재하더라도 제안된 레이저 클리닝 방법을 사용하면 높은 분류 정확도로 분류가 가능함을 확인하였습니다. 또한, 페인트 색상에 따라 레이저 어블레이션 메커니즘과 LIBS에 미치는 영향이 다르기 때문에, 각 페인트 색상에 맞는 다른 클리닝 방식이 필요함을 밝혔습니다. 이를 통해 LIBS 기반 재활용 시스템의 분류 가능성을 입증하였으며, LIBS 기반 재활용 기술의 상용화 가능성을 시사합니다.|Laser-Induced Breakdown Spectroscopy (LIBS) is a powerful analytical technique that enables both quantitative and qualitative analysis by measuring plasma generated through laser irradiation. Its advantages, including rapid measurement, real-time analysis, capability for multi-element detection, and operation in ambient conditions, make it highly relevant across various industrial and research fields. However, when implementing LIBS-based recycling equipment, while clean metal scraps demonstrated high purity and classification accuracy, samples with thick surface contamination, such as paint, proved difficult to classify.
To address this issue, this study analyzed the effects of paint—a representative surface contaminant—on LIBS signals and proposed a laser cleaning method to improve classification accuracy. Black and white paints were applied to aluminum, copper, and stainless steel using varying coating times, and LIBS analysis was performed. Black paint showed broad background signals, non-target signals, and weak target metal signals, affecting LIBS accuracy. On the other hand, white paint, due to its high transmittance, exposed the metal surface with a single laser shot regardless of thickness. While both paints exhibited broad background and non-target signals, white paint showed strong target signals due to nanoparticle effects, differentiating it from black paint.
To minimize these effects, signal processing and cleaning shots with larger spot sizes than the analysis shot were applied. In black paint samples, high classification accuracy was achieved by applying an analysis shot after surface exposure through cleaning shots. LIBS measurements conducted during cleaning shots allowed the identification of strong signal points, enabling precise cleaning shots regardless of paint thickness. The proposed method resulted in higher accuracy and throughput compared to the no-cleaning shot condition. For white paint, high classification accuracy was achieved with just two laser shots, thanks to its high transmittance and nanoparticle effects, eliminating the need for cleaning shots. This demonstrates that using different LIBS measurement strategies based on paint color is more efficient.
In this study, it was confirmed that even in the presence of thick surface contamination such as paint, high classification accuracy can be achieved using the proposed laser cleaning method. Additionally, it was revealed that the laser ablation mechanism and its effect on LIBS vary depending on the paint color, highlighting the need for different cleaning methods for each paint color. This demonstrates the feasibility of classification in LIBS-based recycling systems and suggests the potential for the commercialization of LIBS-based recycling technology.DoctorAbstract i
국문 초록 iii
Contents vi
List of Tables viii
List of Figures ix
1 Introduction 1
1.1 Research background 1
1.2 Automatic sorting machine based on the LIBS 7
1.3 Research objective 18
2 Study on the effects of painted metal during LIBS measurement 20
2.1 Introduction 20
2.2 Experiment 22
2.2.1 Sample 22
2.2.2 LIBS setup 23
2.3 Results and discussion 25
2.3.1 Black paint 25
2.3.2 White paint 35
2.4 Summary 38
3 Method to improve the classification accuracy of painted metals 40
3.1 Training data 40
3.2 Test data 42
3.3 Signal processing 43
3.3.1 Background elimination 43
3.3.2 Line selection 51
3.3.3 Normalization 53
3.4 Classification 54
3.4.1 Classification algorithms 54
3.4.2 Black painted-sample 56
3.4.3 Determination of cleaning shot numbers 62
3.4.4 White-painted samples 72
3.5 Summary 73
4 Conclusions 74
References 76
Acknowledgement 82
Curriculum Vitae 8
Leveraging TIPS-assisted one-pot di-bromination for thiazole-flanked NDI and PDI conjugated n-type semiconductors
No full textHigh-performance unipolar n-type semiconductors are essential for advancing organic electronics. This study explores the impact of fluorination on thiazole-flanked naphthalenediimide (NDI) and perylenediimide (PDI) copolymers with benzothiadiazole (BT) acceptors. A novel one-pot bromination strategy enabled efficient synthesis of these electron-deficient monomers, which were subsequently copolymerized with fluorinated and non-fluorinated BT units. Optical and electrochemical analyses revealed that fluorination systematically lowers the LUMO energy levels, enhancing charge injection and n-type behavior. Fluorine substitution also influences molecular packing, as evidenced by UV-Vis absorption shifts, cyclic voltammetry, and grazing-incidence wide-angle X-ray scattering (GIWAXS). While moderate fluorination improves electron mobility by promoting backbone planarity and π-π stacking, excessive substitution disrupts molecular ordering, reducing charge transport efficiency. The optimized fluorinated copolymers exhibit electron mobilities up to 1.3 × 10−3 cm2 V−1 s−1, demonstrating the potential of fluorination in tuning electronic properties for next-generation hybrid organic semiconductors. © 2025 Elsevier B.V., All rights reserved.TRUEscopu
Guaranteeing Equitable Musical Collaboration: Lessons Learned from the Music-Making Activities in Mixed-Hearing Groups
No full textIntegrating mixed-hearing groups in musical collaboration presents unique challenges and opportunities for their communication and equal contribution. This observational study aims to explore their collaborative work, focusing on the way for equitable music-making. We observed two music-making workshops to identify the potential and dynamics of their musical collaboration. While the first workshop proceeded in a traditional manner of music-making, the second workshop used an assistive tool with multimodality. Our findings highlight the dynamics in musical collaboration that foster engagement and bridge interaction gaps. In turn, sensory inclusion with multimodal music-making promoted role transition in mixed-hearing groups and their equal contributions, leading to the embracing of diverse cultural perspectives. Based on the insights derived from the observations, we propose a design guideline and future research directions for harnessing group dynamics and building equitable musical collaborations for an inclusive environment for mixed-hearing groups.</jats:p