본 연구는 비방사성 SrCl2를 이용하여 Sr 농도를 50, 100, 200mg·kg-1 및 토양 유기물 함량을 5%, 10% 및 15%로 달리하여 배추의 생육, 생체중, 엽록소 함량에 미치는 영향을 생육 시기별로 분석하였다. 그 결과, Sr 농도가 증가할수록 초장, 근장, 엽면적, 생체중 및 건물중이 유의하게 감소하였으며, 특히 Sr 200mg·kg-1 처리에서 생육 저 해가 뚜렷하였다. 반면, 엽록소 함량(SPAD)은 처리 간 유의한 차이를 보이지 않아 광합성 색소에는 Sr의 영향이 제 한적인 것으로 나타났다. 유기물 함량이 높은 토양에서는 Sr 처리에 따른 생육 저해가 완화되었으며, 특히 유기물 15% 조건에서 완충 효과가 가장 크게 나타났다. 이는 유기물이 Sr의 생물유효도를 감소시켜 식물체 흡수를 억제하 는 기작에 의한 것으로 판단된다. 본 연구는 비방사성 SrCl2를 이용한 실험을 통해 작물의 Sr 독성 반응과 유기물 기 반 토양 완충 효과를 정량적으로 규명하였으며, 향후 방사성 오염 토양의 생물학적 복원 및 안전 농산물 생산 전략 수립에 기초자료로 활용될 수 있다.

Efficient donor-acceptor (D-A) molecular scaffolds should be developed for the advancement of organic solar cells (OSCs). Density functional theory (DFT) and time-dependent density functional theory (TDDFT) studies provide an effective methodology to perform initial studies to design and investigate D-A molecular systems. Two fluorine-substituted bis-benzothiadiazoles (FBBTs) are designed and optimized using the DFT method. The results show better planarity for FBBT2, which is attributed to π-extension between the FBBT units. A series of D-A small molecules CB1-4 are designed utilizing FBBT2 to study the effect of systematically substituting carbazole donor and cyano-based acceptor groups on the optoelectronic properties of FBBT. DFT calculations are performed using the B3LYP functional. The designed D-A scaffolds exhibit systematic tuning of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), HOMO-LUMO gap (from 2.333 eV to 1.825 eV). The observed HOMO-LUMO gap follows the trend CB1 > CB2 > CB4 > CB3. The Voc (open-circuit voltage) and power conversion efficiency (PCE) for CB1-4 are presented with the PC71BM acceptor. The overall trend observed for the Voc follows the order CB1 < CB4 < CB2 < CB3. The PCE trend observed using the Scharber model follows the trend CB3 > CB4 > CB2 > CB1. The results show that end cap modeling of π-extended FBBT with cyano-based acceptor groups significantly improves the observed PCE and Voc.

본 연구는 담액수경재배(DFT, Deep Flow Technique) 조건에서 질산태 질소(NO3-N) 결핍이 Perilla frutescens Britt.(잎들깨)의 생육 및 생리적 반응에 미치는 영향을 조사하였다. 야마자키 표준 양액을 기반으로 NO3-N 농도를 0%(대조구), 30%, 50%, 70%, 100%의 5수준으로 단계적으로 감소시킨 처리구를 설정하였다. 처리 시작 후 20일부터 80일까지의 기간 동안, 초장, 엽수, 마디수, 줄기직경 등 주요 생육 지표는 질산태 질소 결핍 (Nitrate Deficiency, ND) 수준이 증가함에 따라 유의하게 감소하였다. 특히, 80일 후 ND 100%(0 mM) 처리구에서 는 생육이 크게 저해되어 초장, 엽수, 마디수, 줄기직경이 각각 49.2%, 59.4%, 41.7%, 42.2% 감소하였다. 생체중과 건물중은 각각 93.4g에서 15.5g, 11.8g에서 3.0g으로 급격히 감소하였다. 식물체 내 총 질소 함량도 ND 수준이 높 아짐에 따라 비례적으로 감소하였으며, ND 0% 대비 ND 100% 처리구에서는 약 50% 이상의 질소 함량 감소가 관 찰되었다. 하엽에서는 황화, 갈변, 괴사 등의 생리적 장애 증상이 뚜렷하게 나타났으며, 이는 엽록소 분해와 관련된 것으로 판단된다. 본 결과는 수경재배 조건에서 잎들깨의 안정적인 생육과 생리적 기능 유지를 위해 충분한 질산 공 급이 필수적임을 보여주며, 상업적 생산을 위한 질산 관리 전략 수립에 기초 자료로 활용될 수 있다.

Sodium-ion batteries (SIBs) offer a viable alternative to partially or fully replace lithium ion batteries (LIBs) due to their lower cost and increased safety. This paper outlines the compositional optimizations, crystallographic evaluations, and electrochemical behavior of a novel mixed NASICON polyanionic compound, NaFe2PO4(SO4)2 (NFPS). X-ray photoelectron spectrometry (XPS) results showed that cobalt doping produces a higher concentration of oxygen defects compared to undoped samples. Scanning electron microscopy (SEM) analysis results revealed that the modified sample has more uniform pores and pore distribution. Brunauer-Emmett-Teller (BET) measurements showed that doping of Co2+ reduces the specific surface area of NFPS-Co0.08 compared to NFPS. This shortens the sodium ion diffusion pathway and promotes ion dynamics. The addition of Co2+ to the sample significantly improved its performance during galvanostatic charge-discharge tests. The electrochemical activity also is significantly enhanced by Co2+ doping. Na0.84Co0.08Fe2PO4(SO4)2 exhibits superior rate and cycling performance compared to pristine NFPS. After 80 cycles at 25 mA g-1, NFPS-Co0.08 retained discharge specific capacity of 60.8 mA h g-1, which is 1.24 times greater than that of NFPS.

The use of aluminum-based hybrid metal matrix composite (HMMC) materials, especially in engine components like pistons, is intended to improve wear resistance and overall performance. Crucial tribological indicators, such as wear and friction coefficients, underscore the significance of these materials. However, present aluminum alloys have limited wear because of clustered reinforced particles and relatively high coefficients of thermal expansion (CTE), resulting in inadequate anti-seizure properties during dry sliding conditions. This research introduces a novel “Hybrid Metal Matrix Composite of Al7068 Reinforced with Fly Ash-SiC-Al2O3”. Al7068 is employed for its superior strength-to-weight ratio and specific modulus, which is ideal for components exposed to cyclic loads and varying temperatures. The integration of fly Ash (FA), silicon carbide (SiC), and alumina (Al2O3) as reinforcements enhances wear resistance, diminishes particle clustering, improves stiffness, mitigates CTE discrepancies, and fortifies the composite against strain and corrosion, thereby enhancing its overall performance. The Stir-casting method was used with optimized reinforcement percentages (10 % total), and comprehensive evaluations through wear tests and mechanical property analyses determined the composite's optimal composition. The proposed HMMC variant with the most suitable reinforcement percentage exhibited enhanced engine piston functionality, reduced wear, low deformation of 0.20 mm, and a comparatively higher ultimate tensile strength of 190 megapascals (Mpa).