김재영 교수

Ferroelectric field effect transistors (FeFETs) have attracted attention as next-generation devices as they can serve as a synaptic device for neuromorphic implementation and a one-transistor (1T) for achieving high integration. Since the discovery of hafnium–zirconium oxide (HZO) with high ferroelectricity (even at a thickness of several nanometers) that can be fabricated by a complementary metal–oxide–semiconductor-compatible process, FeFETs have emerged as devices with great potential. In thi

Accumulation of metal contaminants in soil as a result of various industrial and anthropogenic activities has reduced soil fertility significantly. Phytoextraction of metal contaminants can improve soil fertility and provide inexpensive feedstock for biorefineries. We investigated the hyperaccumulation capacity of sunflower (Helianthus annuus) biomass by cultivating these plants in various concentrations of metal contaminants. Sunflowers were grown in soils contaminated with various levels of he

We present a GUI-based interactive Python program, VIMAP, which generates radio spectral index maps of active galactic nuclei (AGN) from Very Long Baseline Interferometry (VLBI) maps obtained at different frequencies. VIMAP is a handy tool for the spectral analysis of synchrotron emission from AGN jets, specifically of spectral index distributions, turn-over frequencies, and core-shifts. In general, the required accurate image alignment is difficult to achieve because of a loss of absolute spati

Amorphous oxide semiconductors (AOS) containing transition metals have garnered significant attention as promising alternatives to conventional semiconductors due to their various technical advantages, including low-temperature large-area deposition, the ability to maintain performance under mechanical deformation, and high carrier mobility even in the amorphous state. This review analyzes the crystallinity, deposition conditions, and electrical properties of indium gallium zinc oxide (IGZO), a

As electronic circuit integration intensifies, there is a rising demand for dielectric insulators that provide both superior insulation and high dielectric constants. This study focuses on developing high-k dielectric insulators by controlling the phase of the Hf_0.5Zr_0.5O₂ (HZO) film with additional doping, utilizing yttrium (Y), tantalum (Ta), gallium (Ga), silicon (Si), and aluminum (Al) as dopants. Doping changes the ratio of tetragonal to monoclinic phases in

Anaplastic thyroid carcinoma (ATC) is a rare malignancy with very poor prognosis. The exact cause underlying its strong aggressive nature is not clear. Here, we discovered the elevated expression of anoctamin-1 (ANO1; Ca2+-activated Cl− channels) in advanced-stage ATC tissue. Using different ATC cell lines, the degree of expression of ANO1 was found to be related to the degree of ATC cell invasion by quantitative reverse transcription polymerase chain reaction and western blotting. Suppression o

Preventing ferroelectric materials from losing their ferroelectricity over a low thickness of several nanometers is crucial in developing multifunctional nanoelectronics. Epitaxially grown 5 at. % yttrium-doped Hf_0.5Zr_0.5O₂ (YHZO) thin films exhibit an atomically smooth surface, an ability to maintain ferroelectricity even at a thickness of 10 nm, and excellent insulating properties, making them suitable for use as gate oxides in ferroelectric thin film transisto

We probe the feasibility of high-frequency radio observations of very rapid flux variations in compact active galactic nuclei (AGN). Our study assumes observations at 230\,GHz with a small 6-meter class observatory, using the SNU Radio Astronomical Observatory (SRAO) as an example. We find that 33 radio-bright sources are observable with signal-to-noise ratios larger than ten. We derive statistical detection limits via exhaustive Monte Carlo simulations assuming (a) periodic, and (b) episodic fl

본 연구에서는 30, 60, 90°C의 증류수를 이용하여 거대억새 내에 존재하는 무기성분을 제거한 후 원료의 화학적 변화 및 열분해 특성 변화를 관찰하였다. 증류수 처리 온도가 증가할수록 거대억새의 탄소함량은 44.0%(control)에서 46.2% (90°C 처리)로 증가하였으며 산소함량은 49.3% (control)에서 47.0% (90°C 처리)로 감소하였다. 또한 증류수 처리 온도가 증가함에 따라 거대억새 내 회분 함량은 4.6% (control)에서 3.2% (90°C 처리)로 점차적으로 감소하는 것을 확인할 수 있었다. 주요 단당류 정량 분석 결과 무기성분 제거에 따른 시료의 당손실은 없는 것으로 확인되었으며 결정화 영역 분석을 통해 셀룰로오스/헤미셀룰로오스 영역의 구조적인 변형도일어나지 않았음을 알 수 있었다. 무기성분 정량 결과 거대억새 내에는 칼륨(5,644 ppm), 인(3,995 ppm), 마그네슘(1,403 ppm), 칼슘(711 ppm) 등이 상당량 존재하는

본 연구에서는 2단계 촉매 분해공정 시스템을 이용하여 효과적으로 리그닌을 분해하였으며 리그닌 분해산물로 액 상의 리그닌 오일, 촤, 가스가 생성되었다. 1차 촉매 분해공정에서는 MgO, CaO, Pt/C 촉매를 사용하였으며 Pt/C 촉매 를 사용했을 때 가장 높은 리그닌 오일 수율(76.2 wt%) 및 가장 낮은 촤 수율(4.1 wt%)을 얻을 수 있었다. 리그닌 오 일의 GC-MS/FID 분석을 통해 guaiacol, 4-ethylphenol, 4-methylguaiacol, 4-ethylguaiacol, syringol 등 18종류의 페놀화 합물을 검출하였으며 Pt/C 조건에서 생산된 페놀화합물 수율이 97.8 mg/g lignin로 가장 높았다. 한편 MgO와 CaO에 서 생산된 페놀화합물은 촉매에 흡착되어 상대적으로 낮은 수율을 보였다. Pt/C 조건에서 생산된 리그닌 오일을 다공 성 구조를 가지는 Pd/activated carbon aerogel 촉매 하에서 추가 분해하였다

Miscanthus was subjected to two-step hydrolysis under different concentrations of sulfuric-acid (first-step: 72–18%; second-step: 36 2%) for conversion to monomeric sugars and lignin-rich solid residues. Compared to native lignin isolated from Miscanthus, there were obvious reductions of phenolichydroxyl(0.5–2.6% vs. 5.9%) and methoxyl groups(3.0–13.9% vs. 16.5%) in solid residues. TGA confirmedthat thermal stability of solid residues was proportional to greater abundance of condensed ligninstru

Sodium carbonate is an abundant, low-cost, and low-hazard raw material widely used as a food additive and CO₂ absorbent in the food industry. However, its application in food packaging is limited because it is used in solid form, either in sachets or as a compounding ingredient in plastics. Solid sodium carbonate requires an external moisture supply for CO₂ absorption, with its performance dependent on moisture availability. This limitation hinders its commercialization in

Active Galactic Nuclei (AGN) with bright radio jets offer the opportunity to study the structure of and physical conditions in relativistic outflows. For such studies, multi-frequency polarimetric very long baseline interferometric (VLBI) observations are important as they directly probe particle densities, magnetic field geometries, and several other parameters. We present results from first-epoch data obtained by the Korean VLBI Network (KVN) within the frame of the \emph{P}lasma Physics of \e