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        검색결과 1,527

        64.
        2023.11 구독 인증기관·개인회원 무료
        Heavy water (deuterium oxide, D2O) is water in which hydrogen atoms (1H, H), one of the constituent elements of water molecules, have been replaced with deuterium (2H, D), a heavier isotope. Heavy water is used in a variety of industries, including semiconductors, nuclear magnetic resonance, infrared spectroscopy, neutron deceleration, neutrino detection, metabolic rate studies, neutron capture therapy, and the production of radioactive materials such as plutonium and tritium. In particular, heavy water is used as a neutron moderator or coolant in nuclear reactors and as a fuel for nuclear fusion energy, methods for measuring heavy water are becoming increasingly important. There are methods with density, mass spectrometry, and infrared (IR) spectroscopy. In this study, Fourier transform infrared spectroscopy (FT-IR) was used, which is commonly used in IR spectroscopy because of its relatively high analytical sensitivity, low operating costs, and easy online analysis. Heavy water was identified in the range of 2,300-2,600 cm-1 wavenumber (O-D) and the range of 1,200-1,300 cm-1 wavenumber (D-O-D), which are known to be the range with strong infrared absorption. As a result, the linearity of infrared absorbance for each heavy water concentration was confirmed within the relative expansion uncertainty (k=2).
        65.
        2023.11 구독 인증기관·개인회원 무료
        Copper hexacyanoferrate (Cu-HCF), which is a type of Prussian Blue analogue (PBA), possesses a specific lattice structure that allows it to selectively and effectively adsorb cesium with a high capacity. However, its powdery form presents difficulties in terms of recovery when introduced into aqueous environments, and its dispersion in water has the potential to impede sunlight penetration, possibly affecting aquatic ecosystems. To address this, sponge-type aluminum oxide, referred to as alumina foam (AF), was employed as a supporting material. The synthesis was achieved through a dip-coating method, involving the coating of aluminum oxide foam with copper oxide, followed by a reaction with potassium hexacyanoferrate (KHCF), resulting in the in-situ formation of Cu-HCF. Notably, Copper oxide remained chemically stable, which led to the application of 1, 3, 5-benzenetricarboxylic acid (H3BTC) to facilitate its conversion into Cu-HCF. This was necessary to ensure the proper transformation of copper oxide into Cu-HCF on the AF in the presence of KHCF. The synthesis of Cu-HCF from copper oxide using H3BTC was verified through X-ray diffraction (XRD) analysis. The manufactured adsorbent material, referred to as AF@CuHCF, was characterized using Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). These analyses revealed the presence of the characteristic C≡N bond at 2,100 cm-1, confirming the existence of Cu-HCF within the AF@CuHCF, accounting for approximately 3.24% of its composition. AF@CuHCF exhibited a maximum adsorption capacity of 34.74 mg/g and demonstrated selective cesium adsorption even in the presence of competing ions such as Na+, K+, Mg2+, and Ca2+. Consequently, AF@CuHCF effectively validated its capabilities to selectively and efficiently adsorb cesium from Cs-contaminating wastewater.
        66.
        2023.11 구독 인증기관·개인회원 무료
        Pt/C catalysts were prepared using black carbon (CB), and evaluated for their potential application as a catalyst of liquid-phase catalystic exchange for tritium treatment. CB was treated with 10% H2O2 solution for 0 and 2 hours at 105°C, Ethylene glycol and 40wt% Pt were added to the dried treated sample to prepare a Pt/C catalyst. The physical and chemical properties of the prepared catalysts were evaluated by BET, XRD, elemental analysis (EA), and TEM analyses. As a result of BET analysis, the surface area of CB without 10% H2O2 was 237.2 m2·g-1, and after treatment with 10% H2O2, it decreased to 181.2 m2·g-1 for 2 hours. However, the internal surface area increased, indicating the possibility that more Pt could be distributed inside the CB treated with 10% H2O2. In the XRD analysis results, the presence of Pt was confirmed by observing the Pt peak in the prepared Pt/C catalyst, and it was also observed through TEM analysis that Pt was evenly distributed within the CB. The elemental analysis (EA) results showed that the ratio of S and N decreased and the ratio of O increased with increasing 10% H2O2 treatment time. The H2O2 treated carbon supported Pt catalysts and polytetrafluoroethylene were then loaded together on a foamed nickel carrier to obtain hydrophobic catalysts. Our hydrophobic Pt catalyst using H2O2 treated black carbon are expected to be usefully used in the tritium treatment system.
        67.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this work, norepinephrine (NE) was determined by an electrochemical sensor represented by a carbon paste electrode boosted using nitrogen-doped porous carbon (NDPC) derived from Spirulina Platensis microalga anchored CoFe2O4@ NiO and 1-Ethyl-3-methylimidazolium acetate (EMIM Ac) ionic liquid. The morphological characteristics of the catalyst were recorded by field emission scanning electron microscope (FE-SEM) images. Moreover, the electrochemical behavior of norepinephrine on the fabricated electrode was checked using various voltammetric methods. All tests were done at pH 7.0 as the optimized condition in phosphate buffer solution. The results from linear sweep voltammetry revealed that the electro-oxidation of norepinephrine was diffusion, and the diffusion coefficient value was obtained by chronoamperometry (D⁓6.195 × 10– 4). The linear concentration of the modified electrode was obtained from 10 to 500 μM with a limit of detection of 2.26 μM using the square wave voltammetry (SWV) method. The sensor selectivity was investigated using various species, and the results from stability and reproducibility tests showed acceptable values. The sensor's efficiency was tested in urine and pharmaceutical as real samples with recovery percentages between 97.1% and 102.82%.
        4,200원
        68.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A novel kind of self-assembled graphene quantum dots-Co3O4 (GQDs-Co3O4) nanocomposite was successfully manufactured through a hydrothermal approach and used as an extremely effectual oxygen evolution reaction (OER) electrocatalyst. The characterization of morphology with scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that Co3O4 nanosheets combined with graphene quantum dots (GQDs) had a new type of hexagonal lamellar selfassembly structure. The GQDs-Co3O4 electrocatalyst showed enhanced electrochemical catalytic properties in an alkaline solution. The start potential of the OER was 0.543 V (vs SCE) in 1 M KOH solution, and 0.577 V (vs SCE) in 0.1 M KOH solution correspondingly. The current density of 10 mA cm− 2 had been attained at the overpotential of 321 mV in 1 M KOH solution and 450 mV in 0.1 M KOH solution. Furthermore, the current density can reach 171 mA cm− 2 in 1 M KOH solution and 21.4 mA cm− 2 in 0.1 M KOH solution at 0.8 V. Moreover, the GQDs-Co3O4 nanocomposite also maintained an ideal constancy in an alkaline solution with only a small deterioration of the activity (7%) compared with the original value after repeating potential cycling for 1000 cycles.
        4,000원
        69.
        2023.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Infrared radiation (IR) refers to the region of the electromagnetic radiation spectrum where wavelengths range from about 700 nm to 1 mm. Any object with a temperature above absolute zero (0 K) radiates in the infrared region, and a material that transmits radiant energy in the range of 0.74 to 1.4 um is referred to as a near-infrared optical material. Germanatebased glass is attracting attention as a glass material for infrared optical lenses because of its simple manufacturing process. With the recent development of the glass molding press (GMP) process, thermal imaging cameras using oxide-based infrared lenses can be easily mass-produced, expanding their uses. To improve the mechanical and optical properties of commercial materials consisting of ternary systems, germanate-based heavy metal oxide glasses were prepared using a melt-cooling method. The fabricated samples were evaluated for thermal, structural, and optical properties using DSC, XRD, and XRF, respectively. To derive a composition with high glass stability for lens applications, ZnO and Sb2O3 were substituted at 0, 1, 2, 3, and 4 mol%. The glass with 1 mol% added Sb2O3 was confirmed to have the optimal conditions, with an optical transmittance of 80 % or more, a glass transition temperature of 660 °C, a refractive index of 1.810, and a Vickers hardness of 558. The possibility of its application as an alternative infrared lens material to existing commercial materials capable of GMP processing was confirmed.
        4,000원
        70.
        2023.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Tb3+-doped CaNb2O6 (CaNb2O6:Tb3+) thin films were deposited on quartz substrates at a growth temperature of 300 °C using radio-frequency magnetron sputtering. The deposited thin films were annealed at several annealing temperatures for 20 min and characterized for their structural, morphological, and luminescent properties. The experimental results showed that the annealing temperature had a significant effect on the properties of the CaNb2O6:Tb3+ thin films. The crystalline structure of the as-grown CaNb2O6:Tb3+ thin films transformed from amorphous to crystalline after annealing at temperatures greater than or equal to 700 °C. The emission spectra of the thin films under excitation at 251 nm exhibited a dominant emission band at 546 nm arising from the 5D4 → 7F5 magnetic dipole transition of Tb3+ and three weak emission bands at 489, 586, and 620 nm, respectively. The intensity of the 5D4 → 7F5 (546 nm) magnetic dipole transition was greater than that of the 5D4 → 7F6 (489 nm) electrical dipole transition, indicating that the Tb3+ ions in the host crystal were located at sites with inversion symmetry. The average transmittance at wavelengths of 370~1,100 nm decreased from 86.8 % at 700 °C to 80.5 % at an annealing temperature of 1,000 °C, and a red shift was observed in the bandgap energy with increasing annealing temperature. These results suggest that the annealing temperature plays a crucial role in developing green light-emitting CaNb2O6:Tb3+ thin films for application in electroluminescent displays.
        4,000원
        71.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study evaluated a potential sterilization process that uses calcium hypochlorite (Ca(ClO)2) as a disinfectant and hydrogen peroxide (H2O2) as a neutralizing agent for monoculture processes of microalgae (Nannochloropsis oculata). The results showed that no contaminants (prokaryote) were present when the Ca(ClO)2 concentration was greater than 0.010%. The use of an equivalent amount of H2O2 completely neutralized Ca(ClO)2 and had an additional bactericidal effect because of the formation of singlet oxygen. No substantial difference was observed in the biomass accumulation and chlorophyll contents compared to those in cultures sterilized using conventional physical methods such as autoclaving. Therefore, chemical sterilization using Ca(ClO)2 and H2O2 has an excellent economic advantage, and we expect the proposed ecofriendly chemical sterilization method to become a critical culture technology for microalgae-related industrialization.
        4,000원
        72.
        2023.10 구독 인증기관·개인회원 무료
        대파(Allium fistulosum L.)는 동양에서 옛날부터 중요한 식재료로 재배되어온 중국 원산지의 향신 채소이다. 적어도 통일신라시대부터 재배되어 온 기록이 있으며 현재에도 식재료로 수요가 많아 전국적으로 재배면적이 넓어지고 있고, 종자의 유통량 또한 많다. 대파에는 파굴파리(Liriomyza chinensis), 파좀나방(Acrolepiopsis sapporensis), 파밤나방(Spodoptera exigua) 등이 주요 해충으로 알려져 있다. 전남 진도군은 국내 대파 주산단지로 파밤나방의 발생이 많고 다이아마이드 계통 농약의 저항성이 발현되고 있어 계대사육에 따른 저항성 감소를 실험하고자 한다. 실험은 진도군의 대파밭에서 파밤나방 개체를 채집하여 실내에서 약제처리를 통해 살충률과 섭식률을 검정, 몇세대에 걸쳐 저항성이 감소되는지 알고자 한다.
        73.
        2023.10 구독 인증기관·개인회원 무료
        The subfamily Acronictinae is established by Harris in 1841 based on the type species, Acronicta leporina.. In the Korean penisula, the acronictine moth Acronicta cuspis was initially reported by leech in 1889, and a total 45 species have been recorded to date. This brief overview cover adult and larval morphology, as well as ecological data, for more profound comprehension of the Acronictinae. Additionally, further research direction could involve conducting a phylogenetic analysis and clarifying the evolutionary relationships within the subfamily.
        74.
        2023.10 구독 인증기관·개인회원 무료
        The striped fruit fly, Zeugodacus scutellata., is ubiquitous in agricultural areas, making it a critical pest to monitor and manage. It is necessary to develop a technique for rearing Z. scutellata in the laboratory to achieve mass production for biological control. The pumpkin is an important host plant for Z. scutellata; females lay their eggs on the tops of pumpkin flower buds, and larvae consume the stamens from top to bottom before dropping to the ground. Several types of diets are considered in the present study, including liquid, solid, and semisolid diets. Methyl benzoate, propionic acid, sodium benzoate, and citric acid were tested for their ability to suppress microbial contamination and improve the shelf life of diets. Fresh pumpkin, pumpkin flower, and pumpkin powder were used as primary ingredient. Reared adults were tested for their egg laying and survival abilities based on different diets. Approximately 86% of adults emerged from liquid and semisolid diets. Solid diets reduce pupae production and adult emergence. The diets with a total viability of less than 75% were discarded, which is considered as a reasonable threshold to determine whether a diet is nutritionally sufficient to rear the flies. Based on the results of the present study, we have developed a diet for mass rearing in laboratories, which may assist in providing a scientific basis for the effective control of Z. scutellata.
        75.
        2023.10 구독 인증기관·개인회원 무료
        본 연구는 주변 환경의 차이에 따른 화분매개곤충의 유입 특성을 파악하기 위하여 국립수목원 내 진화속을걷 는정원과 부추속전문전시원에 식재된 울릉산마늘의 화분매개곤충을 조사하였다. 2023년 5월 22일부터 6월 2일 까지 꽃이 70% 이상 개화하였을 때 포충망을 활용하여 8일간 곤충을 채집하였고, 각 전시원 별 식생(피도), 기후 (온도·습도·조도)를 조사하였다. 조사 결과 진화속을걷는정원에서 피도 60% 온도 26.4℃, 습도 31.5%, 조도 40953.6lx, 화분매개곤충 20과 450개체, 부추속전문전시원은 피도 90%, 온도 25.6℃, 습도 31.6%, 조도 6387lx, 화분매개곤충 15과 196개체로 나타났다. 온도와 조도가 상대적으로 높은 진화속을걷는정원이 채집된 곤충의 다양성과 방문 빈도가 높았다. 시간대별 곤충의 방문 빈도를 비교해본 결과 온도와 조도는 개체수가 증가할 때 같이 증가하는 경향을 보였으며, 습도는 반대의 경향을 보였다.
        76.
        2023.10 구독 인증기관·개인회원 무료
        왕담배나방은 기주범위가 넓은 다식성으로 토마토, 옥수수, 담배, 해바라기, 땅콩, 면화, 콩 등 다양한 작물에 피해를 주는 해충이며, 장거리 이동성 해충으로도 유명하다. 본 연구에서는 기존 자료를 바탕으로 월동번데기의 성충으로 우화모델(2종)를 작성하고 포장 실측자료와 비교하여 평가하였다. 월동 번데기는 휴면을 종료한 후 안점소실 과정을 거쳐 정상의 번데기로 이행되고 비로소 성충으로 우화하는 것으로 가정하였다. 첫 번째 모형(모 형 1)은 2단계 휴면후발육 우화모형으로 안점소실에 필요한 적산온도 59.9DD (발육영점온도 15.9℃)와 번데기 발육완료에 필요한 192.3DD (발육영점온도 10.2℃)로 구성하였다. 두 번째 모형(모형 2)은 온도자극 우화모형으 로 17.63℃의 온도자극 이후에 번데기 발육을 개시하는 모형이었다. 적산온도는 단순 평균온도법과 사인곡선법 으로 계산하여 비교하였다. 포장자료와 비교 결과 모형 1에 사인곡선법을 적용했을 때 실측치와 편차가 3일보다 작거나 차이가 없었다. 반면 사인곡선법을 적용한 모형 2는 3~6.5일의 편차가 있었다. 평균온도법을 적용한 경우 두 모형 모두 실측치와 편차가 증가하였다. 모형을 활용하여 예측 우화시기와 트랩유살자료를 비교하여 왕담배 나방의 비래 가능성에 대하여 고찰하였다.
        77.
        2023.10 구독 인증기관·개인회원 무료
        Pine Wilt Disease (PWD) is a disease causing mass deaths of pine trees in South Korea, and the dead trees serve as breeding grounds for insect vectors responsible for spreading the disease to other host trees. Because the PWD requires early monitoring to minimize its damage on domestic forestry, this study aims to develop a species distribution model for predicting the potential distribution of PWD by using artificial neural network (ANN) with time-series data. Among the architectures, the Convolutional Neural Network exhibited the highest performance, achieving a validation accuracy of 0.854 and a cross-entropy loss of 0.401, and the InceptionTime model emerged as the second-best performer. This study identified the best-performing ANN architecture for a spatiotemporal evaluation of PWD occurrence, emphasizing the importance for determining hyperparameters with ecological characteristics and data types to apply deep learning into SDMs.
        78.
        2023.10 구독 인증기관·개인회원 무료
        Leaf-spray in vitro bioassays appraise new aphicidal formulations for managing deleterious plant-feeding aphids. The formulation may utilize alternative and integrated strategies. However, leaf spraying even under controlled conditions may affect aphid reproduction and mortality. This study examines leaf spray applications for optimum and reproducible aphicidal results using tobacco leaves overlaid on cotton fabric or water agar surfaces. Infestation of the undersides of tobacco leaves with nymphs of green peach aphids was used in the assays. Spray distance and volume were optimized using water-sensitive paper to ascertain the best surface coverage. Overlays of the leaves on water agar caused less mortality and greater reproduction than the use of cotton fabric. The relative humidity of the insect-rearing chambers changed with the watering regime for the insect - rearing chambers with cotton fabric; 60% relative humidity was optimal. Relative humidity was not affected by the concentration of agar in the water agar chambers. Applications of the chemical aphicidal standard, Sulfoxaflor, under the optimized conditions exhibited similar times for lethality although the rate was faster with leaves on the cotton fabric than on water agar. These studies establish reproducible and sensitive techniques for assessing the lethality and effects on reproduction of potential aphicidal products.
        79.
        2023.10 구독 인증기관·개인회원 무료
        In the genus Asobara Foester, 1863 (Braconidae: Alysiinae), two new species, Asobara rotundata sp. nov. is described and illustrated. In addition, the DNA barcode region of the mitochondrial cytochrome c oxidase subunit I (COI) were sequenced for the species. An identification key for the Asobara species officially recorded from Korea is provided.
        80.
        2023.10 구독 인증기관·개인회원 무료
        The family Asilidae(robber flies) is one of the representative predatory flies that hunts a variety of insects during the larval and adult stages. There are more than 7,500 known species distributed around the world, and 74 species in 30 genera are recorded in Korea. There are about 270 species of the genus Leptogaster recorded worldwide, and three species (L. augusta, L. basilaris, L. dorsopicta) are recorded in Korea. Through this study, three unrecorded species (L. abdominalis, L. furculata, L. spadix) were identified, and a total of six species were confirmed to be distributed in Korea. We would like to provide general information of the genus Leptogaster, a list of currently distributed species in Korea, photos, diagnostic traits, and so on.
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