Composite-based piezoelectric devices are extensively studied to develop sustainable power supply and selfpowered devices owing to their excellent mechanical durability and output performance. In this study, we design a leadfree piezoelectric nanocomposite utilizing (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 (BCTZ) nanomaterials for realizing highly flexible energy harvesters. To improve the output performance of the devices, we incorporate porous BCTZ nanowires (NWs) into the nanoparticle (NP)-based piezoelectric nanocomposite. BCTZ NPs and NWs are synthesized through the solidstate reaction and sol-gel-based electrospinning, respectively; subsequently, they are dispersed inside a polyimide matrix. The output performance of the energy harvesters is measured using an optimized measurement system during repetitive mechanical deformation by varying the composition of the NPs and NWs. A nanocomposite-based energy harvester with 4:1 weight ratio generates the maximum open-circuit voltage and short-circuit current of 0.83 V and 0.28 A, respectively. In this study, self-powered devices are constructed with enhanced output performance by using piezoelectric energy harvesting for application in flexible and wearable devices.

In this investigation, samples of the chemical (Hg1-xPbxBa2Ca1.8Mg0.2Cu3O8+δ) were prepared utilizing a solid-state reaction technique with a range of lead concentrations (x = 0.0, 0.05, 0.10, and 0.20). Specimens were pressed at 8 tons per square centimeter and then prepared at 1,138 K in the furnace. The crystalline structure and surface topography of all samples were examined using X-ray diffraction (XRD) and atomic force microscopy (AFM). X-ray diffraction results showed that all of the prepared samples had a tetragonal crystal structure. Also, the results showed that when lead was partially replaced with mercury, an increase in the lead value impacted the phase ratio, and lattice parameter values. The AFM results likewise showed excellent crystalline consistency and remarkable homogeneity during processing. The electrical resistivity was calculated as a function of temperature, and the results showed that all samples had a contagious behavior, as the resistivity decreased with decreasing temperature. The critical temperature was calculated and found to change, from 102, 96, 107, and 119 K, when increasing the lead values in the samples from 0.0 to 0.05, 0.10, and 0.20, respectively.

The effects of La3+ substitution for Sr2+-site on the crystal structure and the dielectric properties of (Ba0.7Sr0.3-3x/2Lax) (Ti0.9Zr0.1)O3 (BSLTZ) (0.005 ≤ x ≤ 0.02) ceramics were investigated. The structural characteristics of the BSLTZ ceramics were quantitatively evaluated using the Rietveld refinement method from X-ray diffraction (XRD) data. For the specimens sintered at 1,550 °C for 6 h, a single phase with a perovskite structure and homogeneous microstructure were observed for the entire range of compositions. With increasing La3+ substitution (x), the unit cell volume decreased because the ionic size of La3+ (1.36 Å) ions is smaller than that of Sr2+ (1.44 Å) ions. With increasing La3+ substitution (x), the tetragonal phase fraction increased due to the A-site cation size mismatch effect. Dielectric constant (εr) increased with the La3+ substitution (x) due to the increase in tetragonality (c/a) and the average B-site bond valence of the ABO3 perovskite. The BSLTZ ceramics showed a higher dielectric loss due to the smaller grain size than that of (Ba0.7Sr0.3)(Ti0.9Zr0.1)O3 ceramics. BSLTZ (x = 0.02) ceramics met the X7R specification proposed by the Electronic Industries Association (EIA).

Li1.5Al0.5Ti1.5(PO4)3 (LATP) is considered to be one of the promising solid-state electrolytes owing to its excellent chemical and thermal stability, wide potential range (~5.0 V), and high ionic conductivity (~10-4 S/cm). LATP powders are typically prepared via the sol-gel method by adding and mixing nitrate or alkoxide precursors with chelating agents. Here, the thermal properties, crystallinity, density, particle size, and distribution of LATP powders based on chelating agents (citric acid, acetylacetone, EDTA) are compared to find the optimal conditions for densely sintered LATP with high purity. In addition, the three types of LATP powders are utilized to prepare sintered solid electrolytes and observe the microstructure changes during the sintering process. The pyrolysis onset temperature and crystallization temperature of the powder samples are in the order AC-LATP > CA-LATP > ED-LATP, and the LATP powder utilizing citric acid exhibits the highest purity, as no secondary phase other than LiTi2PO4 phase is observed. LATP with citric acid and acetylacetone has a value close to the theoretical density (2.8 g/cm3) after sintering. In comparison, LATP with EDTA has a low sintered density (2.2 g/cm3) because of the generation of many pores after sintering.

1,2-Dichlorobenzene (1,2-DCB) is in various industries as solvents in herbicides, pesticides, and wax, and as degreasers or in the production of dyes. Studies on the hazards and risks of 1,2-DCB showed that this substance can cause skin corrosion, skin irritability, respiratory irritability, and certain target organ toxicity. Industrial workers are exposed to 1,2-DCB by inhalation or skin exposure and there is a lack of information on human hazards even though they can be exposed to organic compounds such as benzene or other DCB complexes rather than a single substance. In this study, we investigated the specific organ toxicity of 1,2- DCB and sex differences using whole-body inhalation in laboratory mice. Male and female mice were exposed to 0–120 ppm of the test substance for 13 weeks. After euthanization, the organs were collected, histopathological assessments and immunohistochemistry (IHC) were performed, and lipid peroxidation was analyzed. Macro and microscopic lesions were observed in the livers of male mice exposed to the test substance, and microscopic alterations were observed in the nasal cavities of male and female mice. IHC analysis of the liver confirmed a greater increase in cytochrome P450 induction in males than in female mice, and malondialdehyde and 4-hydroxynonenal were increased in both sexes by 1,2-DCB inhalation. Based on the relevant literature and experimental results, 1,2-DCB is believed to cause specific organ toxicity in the livers of male mice and the nasal cavities of both sexes of mice, which is supposed to be related to sex differences in cytochrome P450 induction and changes in lipid and oxidative products associated with the early metabolites of the test substance.

The effects of Ni2+ substitution for Mg2+-sites on the microwave dielectric properties of (Mg1-xNix)(Ti0.95(Mg1/3 Ta2/3)0.05)O3 (0.01 ≤ x ≤ 0.05) (MNTMT) ceramics were investigated. MNTMT ceramics were prepared by conventional solid-state reaction. When the MgO / TiO2 ratio was changed from 1.00 to 1.02, MgTi2O5 was detected as a secondary phase along with the MgTiO3 main phase in the MNTMT specimens sintered at 1,400 °C for 4h. For the MNTMT specimens with MgO / TiO2 = 1.07 sintered at 1,400 °C for 4h, a single phase of MgTiO3 with an ilmenite structure was obtained from the entire range of compositions. The relative density of all the specimens sintered at 1,400 °C for 4h was higher than 95 %. The quality factor (Qf) of the sintered specimens depended strongly on the degree of covalency of the specimens, and the sintered specimens with x = 0.01 showed the maximum Qf value of 489,400 GHz. The dielectric constant (K) decreased with increasing Ni2+ content because Ni2+ had a lower dielectric polarizability (1.23Å3) than Mg2+ (1.32Å3). As Ni2+ content increased, the temperature coefficient of resonant frequency (TCF) improved, from -55.56 to -21.85 ppm/°C, due to the increase in tolerance factor (t) and the lower dielectric constant (K)

1,3-다이옥솔란은 용매, 전해질 및 시약으로서 화학, 페인트 및 제약 산업에서 광범위한 관심을 받고 있는 화합물 이다. 1,3-dioxolane은 주로 독성, 발암성, 폭발성, 자동 인화성이 없으며 다기능성을 가지고 있어, 대부분의 유기 및 수성 용 매 조건에서 우수한 용해성을 가져 고분자 전구체로서 사용된다. 최근 몇 년 동안 이 물질은 배가스 및 천연 가스 혼합물에 서 CO2를 분리하기 위한 CO2 선택적 고분자 전구체로서 점점 더 많은 관심을 받고 있다. Poly(1,3-dioxolane) (PDXL)은 폴 리에틸렌 옥사이드(PEO)보다 높은 에테르 산소 함량을 가지고 있으며, 이는 극성 에테르 산소 그룹이 CO2에 대해 강한 친화 력을 나타내기 때문에 우수한 막 CO2/N2 분리 특성을 보인다. 따라서 PDXL 기반 분리막은 비극성(N2, H2 및 CH4) 가스에 대해 탁월한 CO2 용해도 선택성을 보인다. 그러나 PEO와 마찬가지로 PDXL의 극성기는 고분자 사슬의 밀집도를 증가시키고 고분자 결정화를 유발하여 기체 투과도를 감소시켜 이에 대한 개선이 필요하다. 이 논문에서는 기체 분리 응용 분야에서 PDXL기반 고분자막의 최근 발전과 한계에 대해 알아보고자 한다. 또한 CO2 분리 공정에서 1,3-dioxolane 기반 고분자의 한 계를 극복하기 위한 몇 가지 분자 설계방안에 대해 다루어 보기로 한다.

High-temperature and high-pressure post-processing applied to sintered thermoelectric materials can create nanoscale defects, thereby enhancing their thermoelectric performance. Here, we investigate the effect of hot isostatic pressing (HIP) as a post-processing treatment on the thermoelectric properties of p-type Bi0.5Sb1.5Te3.0 compounds sintered via spark plasma sintering. The sample post-processed via HIP maintains its electronic transport properties despite the reduced microstructural texturing. Moreover, lattice thermal conductivity is significantly reduced owing to activated phonon scattering, which can be attributed to the nanoscale defects created during HIP, resulting in an ~18% increase in peak zT value, which reaches ~1.43 at 100oC. This study validates that HIP enhances the thermoelectric performance by controlling the thermal transport without having any detrimental effects on the electronic transport properties of thermoelectric materials.

본 연구는 2021년 3월 1일부터 2일까지 영동지역에 강설이 발생했던 사례의 종관적, 열역학적, 역학적 특성을 분석한 것이다. 분석에 사용한 자료는 AWS 관측자료, 지상일기도, ERA5 재분석 자료, 레윈존데, 천리안 2A 위성 자 료, WISSDOM 자료 등이다. 사례 기간 영동지역 4개소에서 관측된 적설은 10 cm 이상으로 나타났으며, 북강릉(37.4 cm)에서는 가장 많은 적설을 보였다. 종관 분석결과, 동해상 및 영동지역 주변으로 중·상층 대기의 매우 차고 건조한 대기와 상대적으로 따뜻한 하층 대기의 온도 차이로 대류 불안정이 형성되어 북강릉 지역으로 대류운의 발달과 함께 강설이 나타났다. 특히 열역학적 및 운동학적 연직 분석에서, 하층에서 온위의 연직 경도에 의한 강한 바람과 한랭이류 에 의한 대류 불안정이 영동지역의 강설 발생에 큰 역할을 한 것으로 판단된다. 이러한 결과는 레윈존데의 연직 분석 에서도 확인할 수 있었다.

Li1.3Al0.3Ti1.7(PO4)3(LATP) is considered a promising material for all-solid-state lithium batteries owing to its high moisture stability, wide potential window (~6 V), and relatively high ion conductivity (10-3–10-4 S/cm). Solid electrolytes based on LATP are manufactured via sintering, using LATP powder as the starting material. The properties of the starting materials depend on the synthesis conditions, which affect the microstructure and ionic conductivity of the solid electrolytes. In this study, we synthesize the LATP powder using sol-gel and co-precipitation methods and characterize the physical properties of powder, such as size, shape, and crystallinity. In addition, we have prepared a disc-shaped LATP solid electrolyte using LATP powder as the starting material. In addition, X-ray diffraction, scanning electron microscopy, and electrochemical impedance spectroscopic measurements are conducted to analyze the grain size, microstructures, and ion conduction properties. These results indicate that the synthesis conditions of the powder are a crucial factor in creating microstructures and affecting the conduction properties of lithium ions in solid electrolytes.

Regulations on the concentration of boron discharged from industrial facilities, including nuclear power plants, are increasingly being strengthened worldwide. Since boron exists as boric acid at pH 7 or lower, it is very difficult to remove it in the existing LRS (Liquid Radwaste System) using RO and ion exchange resin. As an alternative technology for removing boron emitted from nuclear power plants, the electrochemical boron removal technology, which has been experimentally applied at the Ringhal Power Plant in Sweden, was introduced in the last presentation. In this study, the internal structure of the electrochemical module was improved to reduce the boron concentration to 5 mg/L or less in the 50 mg/L level of boron-containing waste liquid. In addition, the applicability of the electrochemical boron removal technology was evaluated by increasing the capacity of the unit module to 1 m3/hr in consideration of the actual capacity of the monitor tank of the nuclear power plant. By applying various experimental conditions such as flow rate and pressure, the optimum boron removal conditions using electrochemical technology were confirmed, and various operating conditions necessary for actual operation were established by configuring a concentrated water recirculation system to minimize secondary waste generation. The optimal arrangement method of the 1 m3/hr unit module developed in this study was reviewed by performing mathematical modeling based on the actual capacity of monitor tank and discharge characteristics of nuclear power plant.

The aim of this study was to investigate the effect of isolated lactic acid bacteria (LAB) on the quality of high moisture rye silage. Rye forage (Secale cereale L.) was harvested at the heading stage (27.3% of dry matter (DM)) and cut into approximately 3-5 cm lengths. Then, the forage divided into 4 treatments with different inoculants: 1) No additives (CON); 2) Lactobacillus brevis strain 100D8 at a 1.2 x 105 colony-forming unit (cfu)/g of fresh forage (LBR); 3) Leuconostoc holzapfelii strain 5H4 at a 1.0 x 105 cfu/g of fresh forage (LHO); and 4) Mixture of LBR and LHO (1:1 ratio) applied at a 1.0 x 105 cfu/g of fresh forage (MIX). About 3 kg of forage from each treatment was ensiled into a 20 L mini-bucket silo in quadruplicate for 100 days. After silo opening, silage was collected for analyses of chemical compositions, in vitro nutrient digestibilities, fermentation characteristics, and microbial enumerations. The CON silage had the highest concentrations of neutral detergent fiber and acid detergent fiber (p = 0.006; p = 0.008) and a lowest in vitro DM digestibility (p < 0.001). The pH was highest in CON silage, while lowest in LBR and MIX silages (p < 0.001). The concentrations of ammonia-N, lactate, and acetate were highest in LBR silage (p = 0.008; p < 0.001; p < 0.001). Propionate and butyrate concentrations were highest in CON silage (p = 0.004; p < 0.001). The LAB and yeast counts were higher in CON and LHO silages compare to LBR and MIX silages (p < 0.001). However, the mold did not detect in all treatments. Therefore, this study could conclude that L. brevis 100D8 and Leu. holzapfelii strain 5H4 can improve the digestibility and anti-fungal activity of high moisture rye silage.

This study investigated the extent to which explicit and implicit instruction improve L1-Arabic speakers’ articulation of English words whose cognates were acquired earlier in their L2 French. Sixty-eight secondary school students, explicit (n=35) and implicit (n=33), participated in a programme incorporating focus-on-pronunciation activities, comprising three 45-minute sessions. Their learning motivation was first rated using an adapted version of Attitude/Motivation Test Battery (AMTB). Their pronunciation improvement was assessed through an oral-reading task. Ten new words were included in the post-test to see if they would generalize the instructed knowledge analogically. Results indicated that both explicit and implicit instruction had a positive impact on the students’ pronunciation advancement. However, the explicit group outperformed the implicit group with both the targeted and untaught words. There was insignificant interaction effect between instructional method and students’ motivation level, with higher motivation uniformly enhancing the effect of instruction. Nevertheless, motivation played a more crucial role in the learnt knowledge transferability when instruction was of implicit.

한국교회는 일제에 의해 자주와 인권이 짓밟혔을 때 천도교와 연합하여 독립만세운동을 일으키고 이에 적극 참여했다. 세계사와 구속사를 이원론적으로 해석하는 자들은 만세운동이 기독교 신앙과 무관하다고 주장한다. 그러나 하나님의 선교(missio Dei)는 구원받은 피조물 위에 그리스도의 주권을 세우는 하나님 나라를 목표로 하며, 교회사뿐 아니라 전체역사를 그 영역으로 삼기 때문에 한국교회가 참여한 만세운동을 신학적으로 해석할 필요가 있다. 이 논문은 하나님 의 선교 관점에서 3·1운동과 익산4·4만세운동을 중심으로 기독교와 의 관련성과 선교역사적 의미를 준비과정과 피해상황에서 서술하고자 한다.

In this article, Pb2Ba1.7Sr0.3Ca2Cu3O10+δ superconductor material was synthesized using conventional solid-state reaction method. X-ray diffraction (XRD) analysis demonstrated one dominant phase 2223 and some impurities in the product powder. The strongest peaks in the XRD pattern were successfully indexed assuming a pseudo-tetragonal cell with lattice constants of a = 3.732, b = 3.733 and c = 14.75 Å for a Pb-Based compound. The crystallite size and lattice strain between the layers of the studied compound were estimated using several methods, namely the Scherrer, Williamson-Hall (W.H), sizestrain plot (SSP) and Halder Wagner (H.W) approach. The values of crystallite size, calculated by Scherrer, W.H, SSP and H.W methods, were 89.4540774, 86.658638, 87.7555823 and 85.470086 Å, respectively. Moreover, the lattice strain values obtained by W.H, SSP and H.W methods were 0.0063240, 0.006325 and 0.006, respectively. It was noted that all crystallite size results are consistent; however, the best method is the size-strain plot because it gave a value of R2 approaching one. Furthermore, degree of crystallites was calculated and found to be 59.003321%. Resistivity analysis suggests zero-resistance, which is typical of superconducting materials at critical temperature. Four-probe technique was utilized to measure the critical temperature at onset Tc(onset), zero resistivity Tc(off set), and transition (width ΔT), corresponding to temperatures of 128 K, 116 K, and 12 K, respectively.

본 논문은 베베른의 ≪3개의 가곡≫ op. 25, no. 1, ‘얼마나 행복한가!’(Wie bin ich froh!) 작 품을 스트라우스(Joseph Straus)의 총체적 성부진행(Total Voice Leading)을 통해 음향 사이 내재 된 모든 성부진행의 가능성들을 조명하고, 음향 간 성부진행의 관계를 다각적 관점에서 분석한 연 구이다. ‘음향 간 성부진행’ 분석을 통해, 베베른의 가곡 작품에 내재되어 있는 음향 간 총체적 성 부진행 구조와 시의 구조, 음악의 형식적 구조의 연관성을 밝히는 것이 본 논문의 목적이다. 이를 위해, 필자는 먼저 본 작품과 관련된 무조음악 이론가들의 선행연구들을 비판적으로 고찰하였으 며, 이를 토대로, 보다 감상자 중심의, 음악 중심의 음향 간 성부진행 분석을 통해 베베른의 작품 에 내재된 음향적 구조를 면밀히 밝히고자 한다. 무조음악의 깊은 층위에서 유기적 진행의 중추 적 역할을 하는 음향 간 성부진행의 구조가 작품 내 시의 의미적 구조와 어떻게 연결되어 ‘의미 화’ 될 수 있는지 필자의 분석을 통해 구체적으로 접근한다.

본 연구는 십자화과 채소인 갓(Brassica juncea) 추출물 을 이용하여 지표성분인 sinigrin의 함량을 분석하고, 내분비계 교란물질 환경호르몬인 비스페놀 A (BPA)로 분화를 유도한 3T3-L1 전구지방세포에서 갓 추출물과 sinigrin 처 리에 대한 지방세포 분화 및 활성산소종(ROS) 생성 억제, 지방 생성 전사인자(PPARγ, C/EBPα, aP2)의 단백질 발현 감소 효능을 평가하였다. 연구 결과에 따르면 HPLC를 이용하여 측정한 갓 추출물 중 sinigrin의 함량은 21.27±0.2 mg/g 인 것으로 나타났다. BPA로 유도된 3T3-L1 전구지방세포에 서 XTT assay 결과 sinigrin 180 μM 및 갓 추출물 300 μg/ mL 농도에서 세포 독성을 보이지 않았으며, 지방세포 분화과정 중 세포 내 지방 축적량과 ROS 생성량을 비교하였을 때 갓과 sinigrin을 처리한 지방세포의 경우 지방축 적량 및 ROS 생성량 모두 유의적으로 감소시키는 것으로 나타났다. 또한, 갓 추출물 및 sinigrin을 처리하였을 때 지 방세포 분화를 조절하는 전사인자 PPARγ, C/EBPα 및 aP2 의 발현이 억제됨을 확인하였다. 이 결과를 통해 갓은 환 경호르몬 비스페놀 A로 유도된 지방세포 내 지방 축적 억제와 더불어 ROS 저감에 효과적으로 작용함을 확인하였다. 향후 sinigrin을 함유한 갓은 BPA로 인한 지질 대사 장애를 예방하는 천연물 유래 기능성 식품 소재로 활용할 가능성이 높은 것으로 기대되며, 추가로 임상 연구 및 작용기전 입증을 위한 in vivo 모델에서의 후속 연구가 진 행되어야 할 것으로 사료된다.