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Silicon Etching Using Copper-Metal-Assisted Chemical Etching: Unveiling the Role of Cu2O in Microscale Structure Fabrication
No full textAchieving precise and cost-effective etching in the field of silicon three-dimensional (3D) structure fabrication remains a significant challenge. Here, we present the successful fabrication of microscale anisotropic Si structures with an etching anisotropy of 0.73 using Cu-metal-assisted chemical etching (Cu-MACE) and propose a mechanism to elucidate the chemical behavior of Cu within the MACE solution. Our study reveals the formation of cuprous oxide (Cu2O) within Cu thin films in the presence of hydrogen peroxide (H2O2), which plays a key role in Si etching. We propose that the holes generated through the reduction of Cu2O back to Cu are transferred to Si, promoting its etching through a galvanic reaction with Cu2O. This Cu-Cu2O cyclic redox process in the Si-Cu2O galvanic cell under the right conditions enables continuous etching of Si and significantly improves the chemical stability of Cu-MACE. Building on this cyclic process mechanism, we demonstrate the catalytic potential of Cu2O for oxide-assisted chemical etching (OACE) by directly using Cu2O in both thin-film and particle forms, rather than starting from Cu. This study opens possibilities for the precise control of Cu-MACE, extends the existing MACE mechanism, and contributes to our understanding of transition metal oxide behavior in OACE. © 2024 American Chemical Society.FALSEsciescopu
A Fast Design Optimization of On-Chip Equalizing Links Using Particle Swarm Optimization
No full textWe propose a fast algorithm to optimize on-chip equalizing link design utilizing a particle swarm optimization (PSO) method. Finding the optimal design parameters of an equalizing link requires too much computation time, because the dependency between design parameters and performances is too complex, while design space is too large. The proposed algorithm greatly reduces the optimization time by utilizing the superior efficiency of PSO in heuristic search. In experiment, on average, the proposed algorithm optimized a link design 168 × faster than the previous state-of-the-art result, requiring only 1/256 evaluation counts, and reduced computation time from about 2 h to 45 s. © 2024 IEEE.FALSEsciescopu
Gas-flow activation of MOFs: unlocking efficient catalysis through dynamic bonding
No full textMetal-organic frameworks (MOFs), characterized by dynamic metal-ligand coordination bonding, have pivotal roles in catalysis, gas storage, and separation processes, owing to their open metal sites (OMSs). These sites, however, are frequently occupied by Lewis-base solvent molecules, necessitating activation to expose the OMSs for practical applications. Traditional thermal activation methods involve harsh conditions, risking structural integrity. This study presents a novel ‘gas-flow activation’ technique using inert gases like nitrogen and argon to eliminate these coordinating solvent molecules at low temperatures, thereby maintaining the structural integrity of MOFs. We specifically explored this method with HKUST-1, demonstrating that gas-flow activation at mild temperatures is not only feasible but also superior in efficiency compared to the conventional thermal methods. This approach highlights the potential for safer, more efficient activation processes in MOF applications, making it a valuable addition to the repertoire of MOF activation techniques. This activation function of inert gas flow allows HKUST-1 as a catalyst for the hydrogenation of acetophenone even at room temperature. In addition, it is demonstrated that this ‘gas-flow activation’ is broadly applicable in other MOFs such as MOF-14 and UTSA-76. Furthermore, the findings reveal that dynamic coordination bonding, the repeating transient dissociation-association of solvent molecules at OMSs, are key mechanisms in facilitating this activation, pointing towards new directions for designing activation strategies that prevent structural damage. © 2025 The Royal Society of Chemistry.TRUEsciescopu
Selective electrosynthesis of ammonia via nitric oxide electroreduction catalyzed by copper nanowires infused in nitrogen-doped carbon nanorods
No full textThe electrochemical nitric oxide reduction reaction (eNORR) is meticulously investigated as an alternative to the energy intensive Haber-Bosch process to produce Ammonia (NH3). However, the eNORR is hindered by NH3 selectivity due to side reactions and mass-transfer limitations. In this work, we rationally designed copper nanowires (Cu NWs) infused in the lotus-root-like multi-nano-channels of the porous N-doped carbon nanorods (Cu-mNCNR) for a high selective eNORR to synthesize NH3 at ambient conditions. The optimized catalyst, Cu-mNCNR2, has achieved the highest NH3 Faradaic efficiency of 79% with NH3 yield rate of 34.5 μmol cm–2 h–1 at −0.4 VRHE. Moreover, the Cu-mNCNR2 has demonstrated a vigorous performance in the 24 h continuous NO electrolysis to produce NH3. Additionally, a prototype device, the Zn-NO battery, was demonstrated. This study shows that the rational design of a catalyst considering mass-transfer limitations is crucial to achieving high selective NH3 electrosynthesis in eNORR. © 2024 Elsevier B.V.FALSEsciescopu
New Ba-V-O type electrode material for Ba battery
No full text본 발명의 일 측면에 따르면, Ba1+xV6O16 (BaVO) (0.1 003c# x 003c# 2) 을 포함하며, 상기 Ba1+xV6O16 (BaVO) (0.1 003c# x 003c# 2) 가 사방정계(orthorhombic) 결정구조를 갖고, 12 003c# a 003c# 13Å, 10 003c# b 003c# 11Å, 16 003c# c 003c# 18Å 의 격자 파라미터(cell parameter)를 갖는 바륨 이온 전지용 전극 물질이 제공된다. 또한, 집전체에 코팅된 제1항에 기재된 Ba1+xV6O16:탄소:폴리비닐리덴 플루오라이드(PVDF)을 8:1:1 (wt%) 로 포함하는 작업 전극(working electrode); 활성탄(activated carbon)을 포함하는 상대 전극(counter electrode); 및 Ba 이온을 포함하는 전해질; 을 포함하는 바륨 이온 전지가 제공된다
Electronic circuit system for interference cancellation in OFDM communication links
No full text본 발명은 OFDM 통신 링크의 간섭 제거를 위한 전자회로 시스템에 관한 것으로, OFDM 방식으로 상호 통신하는 복수의 칩 및 상기 복수의 칩들을 서로 연결하는 복수 개의 유선 채널을 포함하고, 상기 복수의 칩 중 적어도 하나는, 디지털 데이터를 OFDM 방식으로 인코딩하고, 인코딩한 신호를 송신하는 복수 개의 OFDM 송신기를 포함하는 송신부를 포함하고, 상기 복수의 칩 중 적어도 다른 하나는, 상기 송신부로부터 인코딩한 신호를 수신하여 OFDM 방식으로 디코딩하여 출력하는 복수 개의 OFDM 수신기를 포함하는 수신부를 포함하되, 상기 수신부는 상기 유선 채널들 중, FEXT(Far End Crosstalk)가 발생한 유선 채널을 추정하는 채널 추정부를 포함하는 것을 특징으로 한다
Structural Analysis of Cerebral Organoids Using Confocal Microscopy and Transmission/Scanning Electron Microscopy
No full textCerebral organoid cultures from human-induced pluripotent stem cells are widely used to study complex human brain development; however, there is still limited ultrastructural information regarding the development. In this study, we examined the structural details of cerebral organoids using various microscopy techniques. Two protocols were chosen as representative methods for the development of brain organoids: the classic whole-cerebral organoid (Whole-CO) culture technique, and the air–liquid interface-cerebral organoid (ALI-CO) culture technique. Immunostained confocal laser scanning microscopy (CLSM) revealed the formation of the CTIP2- and TBR1-positive cortical deep layer on days 90 and 150, depending on the developmental progress of both methods. Furthermore, the presence of astrocytes and oligodendrocytes was verified through immunostained CLSM utilizing two-dimensional and three-dimensional reconstruction images after a 150-day period. Transmission electron microscopy analysis revealed nanometer-resolution details of the cellular organelles and neuron-specific structures including synapses and myelin. Large-area scanning electron microscopy confirmed the well-developed neuronal connectivity from each culture method on day 150. Using those microscopy techniques, we clearly showed significant details within two representative culture protocols, the Whole-CO and ALI-CO culture methods. These multi-level images provide ultrastructural insight into the features of cerebral organoids depending on the developmental stage. © The Author(s) 2025. Published by Oxford University Press on behalf of the Microscopy Society of America. All rights reserved.FALSEsci
가역적인 마그네슘 금속 배터리 개발을 위한 계면 변화 전략
No full textMagnesium metal batteries, Zn protective interphase, solvation structure optimization, phosphate additiveThe development of next-generation energy storage technologies has driven interest in magnesium metal batteries (MMBs) due to their high energy density, cost-efficiency, and abundance of magnesium resources. However, achieving stable Mg²⁺ plating/stripping and enhancing electrode-electrolyte interfacial stability remain critical challenges. This study addresses these issues through a two-pronged strategy: (1) the fabrication of a zinc-based protective interphase on the magnesium metal anode and (2) the modification of the solvation structure within glyme-based electrolytes. The ex-situ deposition of a Zn coating on the Mg surface significantly mitigates the formation of a resistive passivation layer, leading to enhanced cycling stability and reduced overpotentials. Electrochemical impedance spectroscopy (EIS) reveals a substantial decrease in interfacial resistance, enabling stable cycling for over 150 cycles at a current density of 0.5 mA cm⁻². Concurrently, the introduction of triethyl phosphate (TEP) as a co-solvent in diglyme (G2)-based electrolytes optimizes the Mg²⁺ solvation environment. This approach suppresses the formation of contact ion pairs (CIPs) while promoting solvent-separated ion pairs (SSIPs), facilitating more efficient ion transport. The optimized electrolyte formulation (G2:TEP = 10:1(v:v)) exhibits superior ionic conductivity and Coulombic efficiency, achieving 97.5% efficiency over 100 cycles at a current density of 0.5 mA cm⁻². Full-cell evaluations using a PTCDA organic cathode highlight the synergistic benefits of the Zn protective interphase and the modified electrolyte, with the Zn-MgPTCDA cell delivering an initial capacity of 48.6 mAh g⁻¹ and maintaining 25 mAh g⁻¹ after 50 cycles at a 0.5C rate. This work offers a comprehensive approach to overcoming the interfacial and solvation-related challenges in MMBs, advancing the development of high-performance, cost-effective, and scalable magnesium-based energy storage systems. Keywords: Magnesium metal batteries, Zn protective interphase, solvation structure optimization, phosphate additive|차세대 에너지 저장 기술의 발전은 높은 에너지 밀도, 경제성, 및 풍부한 자원 매장량으로 인해 마그네슘 금속 전지(MMBs)에 대한 관심을 증가시키고 있다. 그러나, 안정적인 Mg²⁺의 도금/탈리(plating/stripping)와 전극-전해질 계면의 안정성 확보는 여전히 해결해야 할 핵심 과제로 남아있다. 본 연구에서는 이러한 문제를 해결하기 위해 두 가지 전략을 제안한다: (1) 마그네슘 금속 음극 표면에 아연(Zn) 기반 보호 계면층을 형성하는 방식과 (2) 글라임(glyme) 기반 전해질의 용매화 구조(solvation structure)를 제어하는 방법이다. Ex-situ 방식으로 Mg 표면에 Zn 코팅을 증착함으로써 불안정한 불활성 계면층의 생성을 억제하고, 과전압을 낮추며, 장기적인 사이클 안정성을 개선하였다. 전기화학 임피던스 분광법(EIS) 분석 결과, 계면 저항이 현저히 감소하여 0.5 mA cm⁻²의 전류 밀도에서 150회 이상의 안정적인 사이클 수명을 확인하였다. 동시에, 다이글라임(G2) 기반 전해질에 트리에틸 인산(Triethyl Phosphate, TEP)을 공동 용매로 도입하여 Mg²⁺의 용매화 환경을 최적화하였다. 이 과정에서 접촉 이온쌍(Contact Ion Pairs, CIPs)의 비율을 줄이고, 용매 분리 이온쌍(Solvent-Separated Ion Pairs, SSIPs)의 비율을 증가시켜 Mg²⁺ 이온의 전도도를 향상시켰다. 최적화된 전해질 조성(G2:TEP = 10:1)은 우수한 이온 전도도와 쿨롱 효율(Coulombic efficiency, CE)을 보여주었으며, 0.5 mA cm⁻²의 전류 밀도에서 100사이클 동안 97.5%의 효율을 달성하였다. 유기 음극 소재인 PTCDA를 활용한 풀 셀 평가 결과, Zn 보호 계면층과 용매화 구조가 최적화된 전해질의 시너지 효과가 확인되었다. Zn-MgPTCDA 풀 셀은 초기 방전 용량 48.6 mAh g⁻¹을 기록했으며, 50사이클 후 25 mAh g⁻¹의 용량을 유지하였다. 본 연구는 MMB의 계면 및 용매화 문제를 해결하기 위한 포괄적인 접근 방안을 제시하며, 고성능, 경제적, 대규모 상용화가 가능한 마그네슘 기반 에너지 저장 시스템 개발에 기여할 수 있을 것으로 기대된다.Abstract i
List of contents ii
List of tables iv
List of figures v
Ⅰ. Introduction 1
1.1 Mg battery 1
1.2 References 3
Ⅱ. A Zinc-based Protective Layer for Magnesium Metal Anode 5
2.1 Introduction 5
2.2 Experimental 6
2.2.1 Material Preparation 6
2.2.2 Fabrication of the Artificial Layer 7
2.2.3 Material Characterization 7
2.2.4 Electrochemical Measurements 7
2.3 Results and Discussion 8
2.3.1 Selection of Mg Surface Coating Material 8
2.3.2 Zn Coating Layer Optimization 11
2.3.3 Mg Metal Surface Characterization 12
2.3.4 Electrochemical Measurements 13
2.4 Conclusions 15
2.5 References 16
Ⅲ. Magnesium Electrolyte Solvation Structure Modification 19
3.1 Introduction 19
3.2 Experimental 21
3.2.1 Material Preparation 21
3.2.2 Electrochemical Measurements 21
3.2.3 Material Characterization 22
3.2.4 Battery Performance 22
3.3 Results and Discussion 23
3.3.1 Selection of Base Electrolyte Solvent 23
3.3.2 Selection of High Donor Number Solvent 24
3.3.3 Optimization of TEP Solvent Content 27
3.3.4 Electrochemical Performance of GTE 10 29
3.3.5 Magnesium Electrolyte Solvation Shell Structure Analysis 31
3.3.6 Electrochemical Analysis 32
3.3.7 Surface Characterization 33
3.3.8 Battery Performance 34
3.4 Conclusions 37
3.5 References 39
Summary (in Korean) 42MasterdCollectio
Sulfone Electrolytes with Improved Thermal Stability for Lithium Ion Batteries
No full textLithium-ion batteries(LIBs), Sulfone-based electrolytes, Non-flammable electrolytes, Battery vent gas(BVG) suppression, Thermal runaway mitigation, Accelerating rate calorimetry(ARC), Differential scanning calo-rimetry(DSC)List of Contents
Abstract i
List of contents iii
List of figures v
Ⅰ. Introduction 1
Ⅱ. Electrochemical Evaluation of Sulfone Electrolyte 8
2.1 Introduction 8
2.2 Experimental 11
2.2.1 Electrolyte Preparation 11
2.2.2 Oxidation Stability Test 12
2.2.3 Ionic Conductivity Measurement 12
2.2.4 Graphite Half-cell Test 13
2.2.5 1Ah Pouch Cell Test 14
2.3 Results and Discussion 15
2.3.1 Electrolyte Preparation 15
2.3.2 Oxidation Stability Test 15
2.3.3 Ionic Conductivity Measurement 18
2.3.4 Graphite Half-cell Test 21
2.3.5 1Ah Pouch Cell Test 24
2.4 Conclusion 27
2.5 References 29
Ⅲ. Safety Evaluation of Sulfone Electrolyte
3.1 Introduction 32
3.2 Experimental 36
3.2.1 Flammability Tests 36
3.2.2 Differential Scanning Calorimetry 36
3.2.3 Battery Vent Gas Analysis 37
3.2.4 Accelerating Rate Calorimetry Analysis 38
3.2.5 Partial Cell Design 38
3.2.6 XPS analysis 40
3.3 Results and Discussion 41
3.3.1 Flammability Tests 41
3.3.2 Differential Scanning Calorimetry 42
3.3.3 Battery Vent Gas Analysis 47
3.3.4 Accelerating Rate Calorimetry Analysis 50
3.3.5 Partial Cell Design 54
3.3.6 XPS analysis 57
3.4 Conclusions 61
3.5 References 63
Summary (in Korean) 68DoctordCollectio
