In this study, NASICON-type Li1+XGaXTi2-X(PO4)3 (x = 0.1, 0.3 and 0.4) solid-state electrolytes for all-solid-state batteries were synthesized through the sol-gel method. In addition, the influence on the ion conductivity of solid-state electrolytes when partially substituted for Ti4+ (0.61Å) site to Ga3+ (0.62Å) of trivalent cations was investigated. The obtained precursor was heat treated at 450 °C, and a single crystalline phase of Li1+XGaXTi2-X(PO4)3 systems was obtained at a calcination temperature above 650 °C. Additionally, the calcinated powders were pelletized and sintered at temperatures from 800 °C to 1,000 °C at 100 °C intervals. The synthesized powder and sintered bodies of Li1+XGaXTi2-X(PO4)3 were characterized using TGDTA, XRD, XPS and FE-SEM. The ionic conduction properties as solid-state electrolytes were investigated by AC impedance. As a result, Li1+XGaXTi2-X(PO4)3 was successfully produced in all cases. However, a GaPO4 impurity was formed due to the high sintering temperatures and high Ga content. The crystallinity of Li1+XGaXTi2-X(PO4)3 increased with the sintering temperature as evidenced by FE-SEM observations, which demonstrated that the edges of the larger cube-shaped grains become sharper with increases in the sintering temperature. In samples with high sintering temperatures at 1,000 °C and high Ga content above 0.3, coarsening of grains occurred. This resulted in the formation of many grain boundaries, leading to low sinterability. These two factors, the impurity and grain boundary, have an enormous impact on the properties of Li1+XGaXTi2-X(PO4)3. The Li1.3Ga0.3 Ti1.7(PO4)3 pellet sintered at 900 °C was denser than those sintered at other conditions, showing the highest total ion conductivity of 7.66 × 10-5 S/cm at room temperature. The total activation energy of Li-ion transport for the Li1.3Ga0.3Ti1.7(PO4)3 solidstate electrolyte was estimated to be as low as 0.36 eV. Although the Li1+XGaXTi2-X(PO4)3 sintered at 1,000 °C had a relatively high apparent density, it had less total ionic conductivity due to an increase in the grain-boundary resistance with coarse grains.

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.

Rechargeable zinc-based batteries (RZBs) with the advantages of high safety, low cost, abundant resources and environmental friendliness, are considered as advanced secondary battery systems that can be applied to large-scale energy storage. As an important cathode material for RZBs, NASICON-type Na3V2( PO4)3 (NVP) possesses three-dimensional and large-scale ion channels that facilitate the rapid diffusion of Zn2+, and has a higher average operating voltage compared with other vanadiumbased compounds, thus exhibiting the possibility of realizing RZBs with high energy density. However, NVP still has some problems, such as poor electronic conductivity and spontaneous dissolution in aqueous solution. The sluggish kinetics of Zn2+ (de)intercalation in NVP and dendritic growth on the Zn anode also contribute to the poor rate performance and short cycle life of the batteries. In this review, optimization strategies for the electrochemical performance of RZBs with NVP as cathode are systematically elaborated, including modification of NVP cathode and optimization of electrolyte. Several mainstream energy storage mechanisms and analysis methods in this battery system are sorted out and summarized. On this basis, the development direction of NVP–RZB system is further prospected.

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.

210Po is a naturally occurring radionuclide of 238U decay series with a half-life of 138.4 days. 210Po is decay products of 222Rn, which escapes into the atmosphere and present in all environments with aerosol particles. Also, 210Po has high radiotoxicity and emits a high alpha energy of 5.305 MeV, and it decays to finally become a stable isotope, 206Pb. Therefore, 210Po entering the body by continuously ingestion or inhalation is likely to cause severe damage to the bone marrow, kidney and spleen and other sites in the body. Accordingly, the World Health Organization (WHO) recommends that screening level of gross alpha for drinking water not exceed 0.5 Bq·L−1. Alpha spectrometry has been mainly used for analysis of 210Po, and for the accurate measurement of alpha particle with short range, it is essential to prepare suitable source for alpha detection. The 210Po alpha source is made by a spontaneous deposition method in which polonium is adsorbed thin and flat onto a metal disc, such as silver, nickel and copper. There are various pretreatment methods to separate and concentrate polonium from water samples prior to spontaneous deposition, including Fe(OH)3 or MnO2 co-precipitation and evaporation. However, in the case of co-precipitation, sample contamination or loss of polonium may occur through the experimental processes, and evaporation lead to not only time-consuming process but also may cause loss of polonium due to the low boiling point of polonium. Therefore, in order to compensate for these problems, an efficient polonium analysis method that directly collects polonium from the original sample without a pretreatment is required. In this study, 210Po in bottled drinking water sold in Korea was analyzed using alpha spectrometry. A high purity silver disc (99.99%) was inserted into a newly designed polonium deposition kit to quickly and conveniently collect polonium from a water sample. The polonium alpha detecting source was made effectively only by the spontaneous deposition method without a complicated pretreatment. The source was measured using a PIPS detector, and the radioactivity concentration of 210Po was calculated using 209Po as a yield tracer.

In this work, Ag3PO4/In2S3 nanocomposites with low loading of In2S3 (5-15 wt %) are fabricated by two step chemical precipitation approach. The microstructure, composition and improved photoelectrochemical properties of the asprepared composites are studied by X-ray diffraction pattern (XRD), field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), photocurrent density, EIS and amperometric i-t curve analysis. It is found that most of In2S3 nanoparticles are deposited on the surfaces of Ag3PO4. The as-prepared Ag3PO4/ In2S3 composite (10 wt%) is selected and investigated by SEM and TEM, which exhibits special morphology consisting of lager size substrate (Ag3PO4), particles and some nanosheets (In2S3). The introduction of In2S3 is effective at improving the charge separation and transfer efficiency of Ag3PO4/In2S3, resulting in an enhancement of photoelectric behavior. The origin of the enhanced photoelectrochemical activity of the In2S3-modified Ag3PO4 may be due to the improved charge separation, photocurrent stability and oriented electrons transport pathways in environment and energy applications.

본 연구는 PO필름과 PE필름을 온실의 피복재로 적용하였을 때 작물 수량 증대 및 에너지 절감에 미치는 영향을 조사하였다. 시험온실은 국립원예특작과학원 시설원예연구소 내에 위치한 단동온실(1-1W) 2동(B21, B23)과 2연동온실(1-2W 형) 2동(B15, B16)을 사용하였다. 단동온실의 규격은 폭 7.2m, 길이 30m, 측고 1.5m, 동고 3.6m 이고, 연동온실의 규격은 폭 8m, 길이 40m, 측고 3.1m, 동고 5.8m의 온실로서 이 중 골조로 된 아치형 표준온실이다. 동절기 시험을 위하여 PO 필름(외피 0.15mm, 내피 0.10mm)을 단동과 연동의 온실 피복재로 사용하였으며 대조구 온실로서 PE필름(외피 0.15mm, 내피 0.10mm)을 단동과 연동에 설치하였다. 시험작물은 완숙토마토 ‘해피니스’를 토양재배 하였고 2019년 12월 3일에 정식하여 2020년 4월 30일까지 재배하였다. 온실내부 야간 설정온도는 15℃를 유지하였으며 주간에는 23∽24℃를 유지할 수 있도록 측창 및 천창을 개방하였다. PO필름의 단동 및 연동온실 내부에서의 일사량, 온습도 등을 측정하였고, 재배 기간 동안의 생육량을 조사하였으며 에너지 절감 효과를 조사 하기 위해 피복재별 시험온실의 온풍난방기 연료 소비량을 조사하였다. 조사 결과 단동온실에서의 일사량은 PO필름 온실 에서 PE필름 온실보다 7% 증가하였고 수확량은 20% 증대되었다. 연동온실에서의 일사량은 PO필름 온실에서 PE필름 온 실보다 11% 증가되었고, 수확량은 9% 증가하였다. 또한 온실내부의 일평균 온습도 측정 결과 단동온실은 PE, PO필름 온실이 19.0℃, 19.1℃, 상대습도 75%를 나타냈고 연동온실 은 PO필름 온실이 19.6℃, 상대습도 57%를 나타냈고 PE필 름 온실이 18.8℃, 상대습도 63%를 나타냈다. 연료 소비량은 단동온실의 PO필름 온실이 PE필름 온실보다 12.4% 절감되 었고 연동온실에서는 PO필름 온실이 PE필름 온실보다 11.5% 절감된 것으로 나타났다.

In this paper, AgCl/Ag3PO4/diatomite photocatalyst is successfully synthesized by microemulsion method and anion in situ substitution method. X-ray diffraction (XRD), photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and ultraviolet-visible spectroscopy (UV-Vis) are used to study the structural and physicochemical characteristics of the AgCl/Ag3PO4/diatomite composite. Using rhodamine B (RhB) as a simulated pollutant, the photocatalytic activity and stability of the AgCl/Ag3PO4/diatomite composite under visible light are evaluated. In the AgCl/Ag3PO4/diatomite visible light system, RhB is nearly 100 % degraded within 15 minutes. And, after five cycles of operation, the photocatalytic activity of AgCl/Ag3PO4/diatomite remains at 95 % of the original level, much higher than that of pure Ag3PO4 (40 %). In addition, the mechanism of enhanced catalytic performance is discussed. The high photocatalytic performance of AgCl/Ag3PO4/diatomite composites can be attributed to the synergistic effect of Ag3PO4, diatomite and AgCl nanoparticles. Free radical trapping experiments are used to show that holes and oxygen are the main active species. This material can quickly react with dye molecules adsorbed on the surface of diatomite to degrade RhB dye to CO2 and H2O. Even more remarkably, AgCl/Ag3PO4/diatomite can maintain above 95 % photo-degradation activity after five cycles.

After flame-retardant treatment by the two different agents, the thermal behaviors of Lyocell fibers are discussed. In this research, H3PO4 and NaCl reduced the degradation rate and increased the char yield of the Lyocell fibers, and also increased the limiting oxygen index with the char yield increased. After treatment, the integral procedure decomposition temperature and the activation energy of Lyocell fibers are significantly increased by various concentration factors. These phenomena were indicated by the dehydration, rearrangement, formation of carbonyl groups, the evolution of carbon monoxide and dioxide, and carbonaceous residue formation. These effects were indicating the slow pathway of flame retardancy for the Lyocell fibers and are attributed to the two different flame-retardant agent treatments.

Spherical Li3V2(PO4)3 (LVP) and carbon-coated LVP with a monoclinic phase for the cathode materials are synthesized by a hydrothermal method using N2H4 as the reducing agent and saccharose as the carbon source. The results show that single phase monoclinic LVP without impurity phases such as LiV(P2O7), Li(VO)(PO4) and Li3(PO4) can be obtained after calcination at 800 oC for 4 h. SEM and TEM images show that the particle sizes are 0.5~2 μm and the thickness of the amorphous carbon layer is approximately 3~4 nm. CV curves for the test cell are recorded in the potential ranges of 3.0~4.3 V and 3.0~4.8 V at a scan rate of 0.01 mV s–1 and at room temperature. At potentials between 3.0 and 4.8 V, the third Li+ ions from the carbon-coated LVP can be completely extracted, at voltages close to 4.51 V. The carbon-coated LVP exhibits an initial specific discharge capacity of 118 mAh g–1 in the voltage region of 3.0 to 4.3 V at a current rate of 0.2 C. The results indicate that the reducing agent and carbon source can affect the crystal structure and electrochemical properties of the cathode materials.

Recently, semi-dried sweet potato is popular as a natural snake for children’s dessert. The drying condition was optimized to obtain high quality of sweet potato by oven drying process. The mashed yellow and chestnut sweet potato was dried using the oven drier at different temperature (50, 60, 70, and 80°C) then evaluated for the moisture content, appearance observation, texture properties, and sugar contents and sensory test in every 2, 6 and 12 hours. During the dehydration and drying process, the ending point of moisture content divided in three zone from 0-2 hour, 4-6 hour and 8-12 hour. The moisture content was dramatically decreased from 0 hour - 8 hour, but after 8 hour there is no significant decrease. Yellow sweet potato dried at 80°C for 6 hours was investigated as good product base on the sensory test, hardness value, and color appearances as compared to chestnut potato.

PO 필름 공급이 경북 성주지역 참외 산업에 미치는 영향을 분석하기 위하여 참외 재배면적, 재배 농가수, 수량 및 소득 등을 분석한 결과, PE 필름은 2010년에 비해 2014년도에는 전국, 경북 성주 지역에서 각각 91.5%, 94.9%, 95.2%로 감소한 반면, PO 필름 보급은 각각 342.5%, 500%, 825% 이었다. 2010년에 비해 2015년 재배면적과 농가수는 각각 8.8%, 11.9% 감소하였다. 수량과 생산량은 각각 38.2%, 25.9% 증가하였다. 조수입은 2010년 3,051 억원에서 2015년 4,020 억원으로 1.3배 증가하였고 소득도 2010년 1,936 억원에서 2015년 4,020 억원으로 2.7배 증가하였다. 이상의 결과를 종합 하면 PO 필름으로 교체되면서, 참외 생산성은 증대되고, 작업 노력 및 유해물질 배출은 감소될 것으로 보여진다.

려말선초 혼란기에 불교는 타락하고 활발했던 조영의 분위기는 침체기에 빠져들었다. 그런 가운데 우리나라 사찰건축의 명맥을 유지된 몇 가지 중요한 원인을 가지고 있었다. 첫째, 건물짓는 기술자가 바로 승장 대목 자신들이라는 점과 혼란기를 틈타 엄격함으로부터 어느 정도 자유스럽게 영조할 수 있었다는 점이다. 이러한 인식의 변화는 그대로 건물에 나타나게 된다. 이러한 대표적인 사례가 사찰 전각 측면공포에 대한 등간격배열방식이다. 그 동안 이 문제에 대해 심도갚은 연구가 진행되지 않은 상태에서 서둘러 규정짓는 자세에 문제가 있었다고 본다. 본 연구는 이러한 문제점을 제기하면서 보다 심도있는 연구가 되기를 바라는 마음에서 고찰되었다.

Impedancemetric NOx (NO and NO2) gas sensors were designed with a stacked-layer structure and fabricated using LaCrxCo1-xO3 (x = 0, 0.2, 0.5, 0.8 and 1) as the receptor material and Li1.3Al0.3Ti1.7(PO4)3 plates as the solid-electrolyte transducer material. The LaCrxCo1-xO3 layers were prepared with a polymeric precursor method that used ethylene glycol as the solvent, acetyl acetone as the chelating agent, and polyvinylpyrrolidone as the polymer additive. The effects of the Co concentration on the structural, morphological, and NOx sensing properties of the LaCrxCo1-xO3 powders were investigated with powder Xray diffraction, field emission scanning electron microscopy, and its response to 20~250 ppm of NOx at 400 oC (for 1 kHz and 0.5 V), respectively. When the as-prepared precursors were calcined at 700 oC, only a single phase was detected, which corresponded to a perovskite-type structure. The XRD results showed that as the Co concentration of the LaCrxCo1-xO3 powders increased, the crystal structure was transformed from an orthorhombic phase to a rhombohedral phase. Moreover, the LaCrxCo1-xO3 powders with 0 ≤ x < 0.8 had a rhombohedral symmetry. The size of the particles in the LaCrxCo1-xO3 powders increased from 0.1 to 0.5 μm as the Co concentration increased. The sensing performance of the stack-structured LaCrxCo1-xO3/Li1.3Al0.3Ti1.7(PO4)3 sensors was found to divide the impedance component between the resistance and capacitance. The response of these sensors to NO gas was more sensitive than that to NO2 gas. Compared to other impedancemetric sensors, the LaCr0.8Co0.2O3/Li1.3Al0.3Ti1.7(PO4)3 sensor exhibited good reversibility and reliable sensingresponse properties for NOx gases.