본 실험에서는 Ti를 기반으로 한 평판 수소 분리막을 설계하여 제조하였다. 새로운 조성의 Ti를 베이스로 한 수소 분 리막을 찾기 위하여 여러 합금들의 물리화학적 특성과 수소투과도 사이의 상관관계에 대해 조사하였다. 이를 바탕으로 신조성의 합금막 2종(Ti14.2Zr66.4Ni12.6Cu6.8 (70 μm), Ti17.3Zr62.7Ni20 (80 μm))을 설계 및 제조하였다. 제조된 평판 수소 분리막은 300~500°C, 1~4 bar의 조건에서 혼합 가스(H2, N2), sweep 가스(Ar)를 이용하여 수소 투과 실험을 진행하였다. Ti14.2Zr66.4Ni12.6Cu6.8 합금 막은 500°C, 4bar에서 최대 16.35 mL/cm2min의 flux를 가지며, Ti17.3Zr62.7Ni20 합금막은 450°C, 4 bar에서 최대 10.28 mL/ cm2min의 flux를 가진다.

Scanning probe microscopy (SPM) has become an indispensable tool in efforts to develop the next generation of nanoelectronic devices, given its achievable nanometer spatial resolution and highly versatile ability to measure a variety of properties. Recently a new scanning probe microscope was developed to overcome the tip degradation problem of the classic SPM. The main advantage of this new method, called Reverse tip sample (RTS) SPM, is that a single tip can be replaced by a chip containing hundreds to thousands of tips. Generally for use in RTS SPM, pyramid-shaped diamond tips are made by molding on a silicon substrate. Combining RTS SPM with Scanning spreading resistance microscopy (SSRM) using the diamond tip offers the potential to perform 3D profiling of semiconductor materials. However, damage frequently occurs to the completed tips because of the complex manufacturing process. In this work, we design, fabricate, and evaluate an RTS tip chip prototype to simplify the complex manufacturing process, prevent tip damage, and shorten manufacturing time.

고분자 분리막의 대표적인 형태 중 하나인 평판형 분리막은 제조가 용이하여 실험실에서 분리막 소재 연구에서부 터 실제 상용 분리막 생산에 이르기까지 널리 활용되는 분리막의 형태이다. 정밀여과 및 한외여과 등에 사용되는 평판형의 다공성 고분자 분리막은 주로 상분리 공정을 통해 제조할 수 있으며, 여기에는 비용매 유도 및 증기 유도 상분리 공정이 활 용된다. 그러나 상분리 공정 특성상 주변 환경과 실험자에 따라 샘플 간 편차가 쉽게 발생하여 재현성의 확보가 어려운 점이 있다. 따라서 개발된 제조기술을 스케일업 및 재현성 확보를 위해 제어된 환경에서 연속식 대면적 제조가 가능한 롤투롤 제 조장치가 필요하며, 본 연구에서는 실험실 스케일의 제조기술을 나이프 및 슬롯다이 롤투롤 공정으로 스케일 업 했을 때 나 타나는 제조 환경 차이에 따른 분리막의 특성 변화를 비교하였다. 최종적으로 연속식 제조공정 인자에 대한 최적화를 통해 대면적 제조 시 분리막의 균일성을 확보하였다.

We report the effect of plastic deformation on the thermoelectric properties of n-type Bi2Te2.5Se0.5 compounds. N-type Bi2Te2.5Se0.5 powders are synthesized by an oxide-reduction process and consolidated via sparkplasma sintering. To explore the effect of plastic deformation on the thermoelectric properties, the sintered bodies are subjected to uniaxial pressure to induce a controlled amount of compressive strains (-0.2, -0.3, and -0.4). The shaping temperature is set using a thermochemical analyzer, and the plastic deformation effect is assessed without altering the material composition through differential scanning calorimetry. This strategy is crucial because the conventional hotforging process can often lead to alterations in material composition due to the high volatility of chalcogen elements. With increasing compressive strain, the (00l) planes become aligned in the direction perpendicular to the pressure axis. Furthermore, an increase in the carrier concentration is observed upon compressive plastic deformation, i.e., the donorlike effect of the plastic deformation in n-type Bi2Te2.5Se0.5 compounds. Owing to the increased electrical conductivity through the preferred orientation and the donor-like effect, an improved ZT is achieved in n-type Bi2Te2.5Se0.5 through the compressive-forming process.

In this study, a core-shell powder and sintered specimens using a mechanically alloyed (MAed) Ti-Mo powder fabricated through high-energy ball-milling are prepared. Analysis of sintering, microstructure, and mechanical properties confirms the applicability of the powder as a sputtering target material. To optimize the MAed Ti-Mo powder milling process, phase and elemental analyses of the powders are performed according to milling time. The results reveal that 20 h of milling time is the most suitable for the manufacturing process. Subsequently, the MAed Ti-Mo powder and MoO3 powder are milled using a 3-D mixer and heat-treated for hydrogen reduction to manufacture the core-shell powder. The reduced core-shell powder is transformed to sintered specimens through molding and sintering at 1300 and 1400oC. The sintering properties are analyzed through X-ray diffraction and scanning electron microscopy for phase and porosity analyses. Moreover, the microstructure of the powder is investigated through optical microscopy and electron probe microstructure analysis. The Ti-Mo core-shell sintered specimen is found to possess high density, uniform microstructure, and excellent hardness properties. These results indicate that the Ti-Mo core-shell sintered specimen has excellent sintering properties and is suitable as a sputtering target material.

This study presents the fabrication and application of a graphene-assisted voltammetry platform for the sensitive detection of nitrate ions in PM2.5 (atmospheric aerosols with a maximum diameter of 2.5 μm). The MoS2/ reduced graphene oxide/ glassy carbon electrode ( MoS2/rGO/GCE) was prepared using a simple and efficient electrochemical deposition method. The rationale behind selecting MoS2/ rGO stems from their individual properties that, when combined, can enhance the electrode’s performance. MoS2 offers excellent electro-catalytic activity and selectivity for nitrate ion detection, while rGO provides high conductivity and a large surface area for enhanced sensitivity. The electrochemical performance of MoS2/ rGO/GCE was investigated and compared with MoS2/ GCE and bare GCE using cyclic voltammetry and electrochemical impedance spectroscopy. The results demonstrated that MoS2/ rGO/GCE exhibited enhanced electro-catalytic activity, high conductivity, and improved selectivity for nitrate ion detection. The optimal pH value for detecting nitrate ions was determined to be 8.0. Differential pulse voltammetry (DPV) was employed to investigate the linear range and detection limit of nitrate ions on MoS2/ rGO/GCE, resulting in a linear range from 1 to 300 μM and a detection limit of 0.35 μM. The reproducibility and the stability of MoS2/ rGO/GCE were assessed, showing satisfactory performance. Real sample analysis from Chengdu City showed a strong correlation between the results obtained using MoS2/ rGO/GCE and ion chromatography, highlighting its potential application in monitoring nitrate ions in PM2.5. The findings of this study contribute to the development of a graphene-assisted voltammetry platform for sensitive nitrate ion detection in PM2.5, offering potential benefits for real-time air pollution monitoring and environmental health assessments.

The lithium ion battery has applied to various fields of energy storage systems such as electric vehicle and potable electronic devices in terms of high energy density and long-life cycle. Despite of various research on the electrode and electrolyte materials, there is a lack of research for investigating of the binding materials to replace polymer based binder. In this study, we have investigated petroleum pitch/polymer composite with various ratios between petroleum pitch and polymer in order to optimize the electrochemical and physical performance of the lithium-ion battery based on petroleum pitch/polymer composite binder. The electrochemical and physical performances of the petroleum pitch/polymer composite binder based lithium-ion battery were evaluated by using a charge/discharge test, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and universal testing machine (UTM). As a result, the petroleum pitch(MP-50)/polymer(PVDF) composite (5:5 wt % ratio) binder based lithium-ion battery showed 1.29 gf mm-1 of adhesion strength with 144 mAh g-1 of specific dis-charge capacity and 93.1 % of initial coulombic efficiency(ICE) value.

The theoretical capacity of silicon-based anode materials is more than 10 times higher than the capacity of graphite, so silicon can be used as an alternative to graphite anode materials. However, silicon has a much higher contraction and expansion rate due to lithiation of the anode material during the charge and discharge processes, compared to graphite anode materials, resulting in the pulverization of silicon particles during repeated charge and discharge. To compensate for the above issues, there is a growing interest in SiOx materials with a silica or carbon coating to minimize the expansion of the silicon. In this study, spherical silica (SiO2) was synthesized using TEOS as a starting material for the fabrication of such SiOx through heating in a reduction atmosphere. SiOx powder was produced by adding PVA as a carbon source and inducing the reduction of silica by the carbothermal reduction method. The ratio of TEOS to distilled water, the stirring time, and the amount of PVA added were adjusted to induce size and morphology, resulting in uniform nanosized spherical silica particles. For the reduction of the spherical monodisperse silica particles, a nitrogen gas atmosphere mixed with 5 % hydrogen was applied, and oxygen atoms in the silica were selectively removed by the carbothermal reduction method. The produced SiOx powder was characterized by FE-SEM to examine the morphology and size changes of the particles, and XPS and FT-IR were used to examine the x value (O/Si ratio) of the synthesized SiOx.

Piezoelectric technology, which converts mechanical energy into electrical energy, has recently attracted drawn considerable attention in the industry. Among the many kinds of piezoelectric materials, BaTiO3 nanotube arrays, which have outstanding uniformity and anisotropic orientation compared to nanowire-based arrays, can be fabricated using a simple synthesis process. In this study, we developed a flexible piezoelectric energy harvester (f-PEH) based on a composite film with PVDF-coated BaTiO3 nanotube arrays through sequential anodization and hydrothermal synthesis processes. The f-PEH fabricated using the piezoelectric composite film exhibited excellent piezoelectric performance and high flexibility compared to the previously reported BaTiO3 nanotube array-based energy harvester. These results demonstrate the possibility for widely application with high performance by our advanced f-PEH technique based on BaTiO3 nanotube arrays.

With the increasing demand for electronic products, the amount of multilayer ceramic capacitor (MLCC) waste has also increased. Recycling technology has recently gained attention because it can simultaneously address raw material supply and waste disposal issues. However, research on recovering valuable metals from MLCCs and converting the recovered metals into high-value-added materials remains insufficient. Herein, we describe an electrospinning (E-spinning) process to recover nickel from MLCCs and modulate the morphology of the recovered nickel oxide particles. The nickel oxalate powder was recovered using organic acid leaching and precipitation. Nickel oxide nanoparticles were prepared via heat treatment and ultrasonic milling. A mixture of nickel oxide particles and polyvinylpyrrolidone (PVP) was used as the E-spinning solution. A PVP/NiO nanowire composite was fabricated via Espinning, and a nickel oxide nanowire with a network structure was manufactured through calcination. The nanowire diameters and morphologies are discussed based on the nickel oxide content in the E-spinning solution.

폴리에틸렌 글라이콜 다이아크릴레이트 (polyethylene glycol diacrylate, PEGDA) 하이드로젤을 정삼투 (forward osmosis, FO) 분리막의 지지체로 사용하여 고성능의 FO 분리막을 제조하였다. 친수성의 PEGDA를 자외선 조사를 통한 중합 과 그에 따른 상분리를 이용하여 다공성으로 구조화하였고, 매우 높은 친수성을 가진 하이드로젤 지지체를 얻을 수 있었다. 제조된 친수성 PEGDA 지지체 위에 높은 수투과도와 염 선택도를 확보하기 위해서 일반적인 계면중합 방식이 아닌 톨루엔 을 유기 용매로 사용한 계면중합 방식(TIP)으로 선택층을 도입하였다. 제조된 PEGDA 지지체 기반 분리막은 1.0 M NaCl 유 도 용액과 증류수 유입수를 통한 FO 성능 측정에서 상용 HTI 분리막들에 비해서 매우 높은 수투과도와 낮은 염 선택도를 나 타내었다. 본 연구를 통해, 기존의 소수성 지지체를 추가적으로 개질하는 방식이 아닌 새로운 물질과 제조방식을 사용한 FO 지지체의 가능성을 제시하고자 한다.

This study investigates the influence of the type of lipid phase (corn oil [CO], palm oil [PO], MCT oil [MO], lemon oil [LO]) on the physical characteristics and bioactive peptide (BP) encapsulation in food-grade water-in-oil-in-water (W/O/W) double emulsions. The stabilities of the double emulsions were analyzed for droplet size characteristics, viscosity, dynamic rheological properties, encapsulation efficiency (EE), and release rate of BP (at different temperatures: 4, 25, 37, and 60oC) for 28 days. The encapsulated BP acts as an active substance in the osmotic balance and destabilization of the double emulsion system. For the effect of the oil phase, double emulsions prepared with PO showed the best droplet stability without phase separation (D50 < 1 m) and high BP retention (EE > 60%). In the release rate at high temperatures (60oC), the BP released from double emulsions was in the order of MO > CO > LO > PO over time. In contrast, the BP release from double emulsions at low temperatures (< 37oC) had no difference depending on the oil type. Therefore, the information obtained from this work is useful for preparing stable, functional food or cosmetic products from double emulsions using a BP.