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        검색결과 1,527

        21.
        2024.04 구독 인증기관·개인회원 무료
        This study investigates the impact of Bursaphelenchus xylophilus infection on the gut bacterial communities of the pine sawyer beetle, Monochamus alternatus, with a distinction between male and female individuals. Utilizing specific primers, we determined the infection status and analyzed the bacterial composition across different taxonomic levels. Regardless of infection status or sex, Proteobacteria and Firmicutes were found to dominate the phylum level, with significant contributions from Actinobacteria and Bacteroidetes. At the class level, Bacilli, Gammaproteobacteria, Alphaproteobacteria, and Actinobacteria emerged as prevalent groups. Meanwhile, the genus level was characterized by a high abundance of Lactobacillus, Rickettsia, Bacillus, and Rahnella. Our analysis of alpha diversity metrics, including Observed Species, Shannon Index, Inverse Simpson Index, and Phylogenetic Diversity, revealed no significant differences attributable to B. xylophilus infection; however, notable variations were observed between sexes. Principal Coordinates Analysis and Non-metric Multidimensional Scaling further underscored that the differences in gut bacterial communities were more pronounced between male and female beetles than between infected and uninfected individuals. These findings highlight the influence of host sex over infection status in shaping the gut microbiome of Monochamus alternatus, providing new insights into the complex interactions between host biology, gut microbiota, and pathogen infection.
        22.
        2024.04 구독 인증기관·개인회원 무료
        국내에서 유통되는 한약재 오공(蜈蚣)의 정·위품 유통 현황 파악과 유전자 감별법 개발을 위해 서로 다른 6개 유통사에서 오공으로 판매중인 전형약재를 구매하여 각 약재 포장 단위별 크기, 색깔, 무늬 등 형태적으로 차이가 있는 개체를 분류하여 국내에서 채집된 왕지네 표본 2개체를 포함 총 30개 시료를 대상으로 DNA 바코드 분석을 실시하였다. 확보한 미토콘드리아 COI 염기서열 정보와 기 등재된 NCBI GenBank 염기서열 정보를 이용하여 계통 분석을 실시한 결과, 28개 약재 시료 중 국산 및 중국산 전형약재 유통품 13 개체는 모두 대한민국약전외한약 (생약)규격집에 정품 기원종으로 수재된 Scolopendra subspinipes mutilans로 확인되었으며, 이들은 국내 채집 왕지네 개체들과 함께 하나의 단계통군을 형성하였다. 하지만 인도네시아산 전형약재 유통품 15 개체의 경우 4개의 그룹으로 구분되었는데, 그 중 3개 그룹은 S. dehaani, S. subspinipes, 그리고 명확한 종을 알 수 없는 Scolopendra sp.로 Scolopendra 속으로 확인되었고 나머지 그룹을 형성하는 한 개체는 Scolopendra 속에 속하지 않고 Rhysida singaporiensis와 89%의 유사도를 보였다. COI 바코드 분석을 통해 국내 유통되는 오공은 원산지가 한국 또는 중국인 경우 모두 정품 기원종으로 확인되었으며, 원산지가 인도네시아인 경우에는 모두 위품인 것으 로 확인되었다. 또한 위품으로 확인된 유통약재는 총 4개의 종으로 분류되었고, 대부분은 정품인 Scolopendra속 의 분류군이었으며 Rhysida속과 가까운 분류군도 오공으로 수입되어 유통되고 있는 것으로 확인되었다.
        23.
        2024.04 구독 인증기관·개인회원 무료
        대표적인 초식곤충인 나방은 기주식물 특이성을 갖고 있어 기주식물 분포에 따른 식생구조나 서식지 유형을 이해하는데 사용이 가능한 분류군이다. 나방은 종 다양성이 높고 분류학적으로 잘 알려져 있어 조사가 많이 이루 어져 풍부한 데이터가 존재하여 이들의 공간적, 시간적 규모의 생물량 변화 추세를 확인할 수 있다. 본 연구에서는 공간적인 유형에 따라 나방의 생물량을 비교하고자 하였다. 생물량을 추정하기 위해 이용된 분류군은 자나방과, 밤나방과, 태극나방과로 이들 분류군의 앞날개 길이를 기준으로 종별로 계산을 하였다. 공간적인 유형은 숲의 위치(연속된 숲, 파편화된 숲)와 숲의 구성(침엽수림, 활엽수림, 혼효림)을 사용하였다. 그 결과 숲의 위치에 따라 생물량은 차이가 존재했지만(F = 16.76, P < 0.001), 숲의 구성(F = 1.54, P = 0.22)과 숲 위치와 구성의 상호작용은(F = 0.34, P = 0.71) 생물량의 차이를 확인하지 못하였다. 숲 구성에 따라 차이가 나타날 것으로 예상하였지만 나타나 지 않은 데에는 추후 분류군을 더 늘려 확인하는 것이 필요하다. 또한 식물 생물량 추정을 통한 곤충과 먹이자원의 가용 관계를 파악하는 연구도 필요할 것으로 예상한다.
        24.
        2024.04 구독 인증기관·개인회원 무료
        The Euonymus defoliator moth, Pryeria sinica Moore (Lepidoptera: Zygaenidae), is a pest that causes considerable damage to the Euonymus genus, especially Euonymus alatus and Euonymus japonicus. The biological characteristics of P. sinica have been studied in China, Japan, Taiwan, and the United States, but there has been no research conducted on this species in Korea. Also, P. sinica has two dormant phases in each generation, one as eggs in winter and the other as pupae in summer. Our purposes are to study the biological characteristics of Korean populations of P. sinica and to examine the effects of temperature and photoperiod on summer diapause. The biological characteristics were investigated in laboratory conditions (25 ± 1 ℃, 65 ± 1% R.H., 16L:8D) and the number of eggs in an egg mass, developmental periods and mortality rate in each larvae stage, and adults’ life span were determined. The results showed that 190.7 ± 31.64 eggs were contained in one egg mass and it took 25.57 ± 0.61 days from 1st larval stage to the pre-pupal stage. P. sinica has 4 larval stages and each stage took 4.28 ± 0.21, 6.2 ± 0.55, 6.02 ± 0.68, and 8.93 ± 0.88 days. The mortality rate of larvae peaked at 22.5% in 3rd larval stage. The adults’ life span was 4.67 ± 0.97 days in males and 4.61 ± 1.82 days in females. To study summer diapause, we divided pupae into 4 groups. Both low temperature and short daytime were effective in shortening the pupal stage. The pupal stage was the shortest in group D (122.12 ± 1.24 days), in which the initial condition was 25 ℃-16L:8D and the altered condition was 16 ℃ -12L:12D, and the longest in group A (161.92 ± 3.15 days, 25 ℃-16L:8D). These data could be utilized to propose the optimal timing for controlling the population of P. sinica.
        25.
        2024.04 구독 인증기관·개인회원 무료
        This study investigates the phenomenon of task specialization in subterranean termites, focusing on their tunneling behavior. Termites, known for their complex social structure, allocate specific individuals for tunnel construction, rarely switching tasks. To explore this behavior, we developed a simulation model comparing termite groups with and without task shifts. While tunnel orientation showed no significant difference between the two tunnel pattern groups, the absence of task shifts resulted in larger tunnels, indicating enhanced foraging efficiency. This suggests that maintaining a consistent division of labor without task rotation benefits termite foraging. This study sheds light on the ecological advantages of task specialization in social insects, highlighting its role in foraging success and colony survival.
        26.
        2024.04 구독 인증기관·개인회원 무료
        This presentation explores the application of Artificial Intelligence (AI) in entomology beyond traditional image analysis. It highlights AI's potential in auditory and olfactory analysis, areas less explored in entomological research. Utilizing machine learning, AI enhances insect classification and ecosystem assessment through improved analysis of existing data. The discussion includes AI's capability in developing indices for habitat evaluation using insects as bioindicators, emphasizing its versatility across different research areas within entomology. This approach aims to broaden the scope of AI applications, promoting a deeper understanding of ecological dynamics through entomological studies.
        27.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        한반도 남부지역에서 점토대토기문화는 청동기시대 후기에 중국 요령지역으로부터 유입된 문화로 유구와 유물에서 재지의 송국리문화와는 이질적이고 단절된 문화상을 보인다. 그러나 점토대토기문화 에서 확인되는 석기를 송국리문화의 석기군과 비교하면 유사점과 차이점을 모두 보이고 있어‘점토대 토기문화의 석기’에 대한 정체성은 명확하게 정의되지 않고 있다. 본고는 점토대토기문화 유적에서 출토된 석기 전반을 검토하고, 재지문화인 송국리문화와의 비교 분석을 통해 점토대토기문화 석기의 범주와 특징을 살펴보았다. 점토대토기문화의 석기는 송국리문화 에서 보이지 않던 새로운 기종의 출현은 확인되지 않지만, 새로운 형식의 출현은 확인되었다. 이러한 새로운 형식을‘점토대토기문화의 석기’로 설정하였다. 점토대토기문화의 석기상은 세 유형으로 분류하였다. Ⅰ유형은 자체적으로 고안한 형식으로, 무경 식석검, 삼각형석촉, 소형 편평양인석부, 단면 장방형의 석제 방추차 등이 있다. Ⅱ유형은 재지문화의 석기를 독창적으로 변형한 형식으로 구하부 직선의 유구석부, 편평유경촉 등이 있다. Ⅲ유형은 재지 문화의 석기를 그대로 수용한 것으로 합인석부, 편평편인석부, 구하부 사선의 유구석부 등이 있다. 이 세 유형은 점토대토기문화 집단이 새로운 환경에 적응하며 발현된 석기상으로 이를 통해 당시 환경에 적응ㆍ정착하는 과정을 유추할 수 있다. 석기상으로 볼 때, 점토대토기문화는 수렵에 비중을 둔 사회였음을 추정할 수 있다.
        6,300원
        28.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        한국 청동기시대의 대표적 무덤은 지석묘이다. 그런데, 남해안을 중심으로 한 남부지역으로는 매장 주체부의 규모를 훨씬 능가하는 규모의 묘역(식)지석묘가 상당수 확인된다. 그리고 묘역지석묘의 평 면형태가 방형과 원형으로 양분되는데 그 선후는 명확치 않다. 이 중 원형의 묘역지석묘 중 성토를 하 여 중심부를 가장 높게 올린 후 그곳에 무덤을 만든 ‘분구묘’가 여럿 확인되었다. 청동기시대의 분 구묘는 그동안 묘역지석묘의 영역내에서 이해되고 있었으나 분구묘 자체의 지역권, 축조방식 등에서 고유의 양식으로 구분될 수 있다. 무엇보다 청동기시대 무덤이 큰 돌(상석)을 올려 주변에 그 존재를 알리는 것이 일반적이었는데, 이와 다른 방식으로 수직적인 규모를 확대한 원형 분구묘의 출현은 청 동기시대 사회를 이해하는 또 다른 자료를 제공하고 있다. 이 분구묘는 청동기시대 후기 송국리문화 단계의 묘역지석묘의 시작과 확장속에서 같이 공반되는 데, 다만 그 분포권이 남해안과 남강유역이 중심지라는 점에서 송국리문화의 또 다른 문화속성으로서 의미가 있다고 보인다. 다만, 이러한 형태의 무덤이 자체발생보다는 북방지역으로부터의 유입 가능성 이 있다는 점에서 상호 관련성을 추가로 검토해야 할 필요가 있다. 흔히 분구묘는 원삼국시대 마한이라는 정치체의 주요 무덤양식으로 알려져 있었는데, 청동기시대 의 분구묘 역시 기본적인 개념에서는 크게 차이가 나지 않는다. 그동안 원삼국시대 분구묘의 기원을 중국에서 찾기도 하였는데, 청동기시대 분구묘의 인식을 계기로 이에 대한 시각 변화가 요구된다.
        5,800원
        29.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the current research, a manganese and cobalt oxides-based nanocatalyst was developed which was used to make an efficient cathode electrode for fuel cells. The nano MnOx/ MnCo2O4 was synthesized through a hydrothermal procedure followed by sintering at 500–600 °C. X-ray diffraction and scanning electron microscopy besides electrochemical techniques were applied for the characterization of the synthesized nanocatalyst. The carbon black type Vulcan (XC-72R) and PTFE were used to prepare the active reaction material of the cathode electrode named carbon paste (CP). Loading of the synthesized nano MnOx/ MnCo2O4 on CP was optimized in a weight ratio of 10–90% for the oxygen reduction process in neutral conditions. The best performance was gained for the 50 W% MnOx/ MnCo2O4 loaded CP, whose active surface area was twice the bare CP. The values of the exchange current density of the ORR obtained by electrode containing 50 W% MnOx/ MnCo2O4 was calculated as 0.12 mA/cm2. The low price, good catalytic efficiency, and cyclic stability of the MnOx/ MnCo2O4 nanocatalyst compared to the commercial platinum-based catalysts confirm its ability to develop fuel cell electrodes.
        4,000원
        30.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fe3O4/g-C3N4/TiO2 catalyst has been fabricated using a simple ultrasonic method with high photocatalytic activity. The morphology, structure and optical properties of Fe3O4/ g-C3N4/TiO2 were systematically investigated by a variety of characterization techniques. The optimum degradation conditions were investigated by degrading tetracycline (TC) under visible light irradiation. The results showed that the degradation efficiency was the highest when the initial TC concentration was 5.0 mg/L, the pH value was 11 and the catalyst dosage was 1.0 g/L. After 100 min of visible light irradiation, the degradation efficiency of TC achieved at 73.61%, which was 1.64 and 1.19 times that of g-C3N4 and Fe3O4/ g-C3N4, respectively. Moreover, Fe3O4/ g-C3N4/TiO2 had good stability and recyclability. The results of capture experiments showed that ‧O2 − and ‧OH were the main active species during the photocatalytic process, and a possible photocatalytic reaction mechanism of Fe3O4/ g-C3N4/TiO2 catalyst was proposed. This study provides a new way to improve the photocatalytic performance of g-C3N4, which has great potential in degrading pollutants such as antibiotics in wastewater.
        4,000원
        31.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 실험에서는 α-Al2O3 지지체에 무전해도금을 이용하여 Pd-Ag-Cu 분리막을 제조하였다. Pd, Ag, Cu는 각각 무 전해도금을 통해 지지체 표면에 코팅하였고, 합금의 형성을 위해 무전해도금 중간에 H2, 500°C의 조건에서 18 h 동안 열처리 를 진행하였다. 이를 통해 제조된 Pd-Ag-Cu 분리막은 SEM을 통해 표면을 관찰하였으며, Pd 분리막의 두께는 7.82 μm, Pd-Ag-Cu 분리막의 두께는 3.54 μm로 측정되었다. EDS와 XRD 분석을 통해 Pd-Ag-Cu 합금이 Pd-78%, Ag-8.81%, Cu-13.19%의 조성으로 형성된 것을 확인하였다. 기체투과 실험은 H2 단일가스와 H2/N2 혼합가스에서 실험을 진행하였다. H2 단일가스에서 측정한 수소 분리막의 최대 H2 flux는 Pd 분리막의 경우 450°C, 4 bar에서 74.16 ml/cm2·min이고, Pd-Ag-Cu 분리막의 경우 450°C, 4 bar에서 113.64 ml/cm2·min인 것을 확인하였고, H2/N2 혼합가스에서 측정한 separation factor의 경우 450°C, 4 bar에서 각각 2437, 11032의 separation factor가 측정되었다.
        4,000원
        32.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        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.
        4,000원
        33.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Photoanode optimization is a fascinating technique for enlightening the power conversion efficiency (PCE) of dye-sensitized solar cells (DSSCs). In this present study, V2O5/ ZnO and reduced graphene oxide (rGO)-V2O5/ZnO nanocomposites (NCs) were prepared by the solid-state technique and used as photoanodes for DSSCs. A wet chemical technique was implemented to generate individual V2O5 and ZnO nanoparticles (NPs). The structural characteristics of the as-synthesized NCs were investigated and confirmed using powder X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), and Scanning electron microscope (SEM) with energy dispersive X-ray (EDX) analysis. The average crystallite size (D) of the as-synthesized V2O5/ ZnO and rGO-V2O5/ZnO NCs was determined by Debye-Scherer’s formula. The bandgap (eV) energy was calculated from Tauc’s plots, and the bonding nature and detection of the excitation of electrons were investigated using the Ultra violet (UV) visible spectra, Fourier Transform infrared (FTIR) and photoluminescence (PL) spectral analysis. Electrical studies like Hall effect analysis and the Nyquist plots are also described. The V2O5/ ZnO and rGO-V2O5/ZnO NCs based DSSCs exhibited 0.64% and 1.27% of PCE and the short circuit current densities and open circuit voltages improved from 7.10 to 11.28 mA/cm2 and from 0.57 to 0.68 V, respectively.
        4,300원
        34.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We analyzed the performance of hubless rim propellers based on the number of blades, maintaining a fixed pitch ratio and expanded area ratio, using computational fluid dynamics (CFD). Thrust coefficient, torque coefficient and efficiency according to the number of blades were analyzed. In addition, the pressure distribution on the discharge and suction sides of the blade was analyzed. As the advance ratio increases, the thrust coefficient decreases. The highest thrust was shown when the advance ratio was lowest. For the three, four, five and six-blades, the torque coefficient tended to decrease as the advance ratio increased. In the case of seven and eight-blades, the torque coefficient tended to increase as the advance ratio increased. The maximum efficiency was found when the advance ratio was 0.8. When the three-blade, it showed high efficiency at all advance ratios. A high pressure distribution was observed at the leading edge of the discharge blade, and a low pressure distribution was observed at the trailing edge. Applying a hubless rim-driven thruster with the three-blade can generate higher thrust and increase work efficiency.
        4,000원
        35.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to present a predictive drift model, Jeju National University's training ship was tested for about 11 hours and 40 minutes, and 81 samples that selected one of the entire samples at ten-minute intervals were subjected to regression analysis after verifying outliers and influence points. In the outlier and influence point analysis, although there is a part where the wind direction exceeds 1 in the DFBETAS (difference in Betas) value, the CV (cumulative variable) value is 6%, close to 1. Therefore, it was judged that there would be no problem in conducting multiple regression analyses on samples. The standard regression coefficient showed how much current and wind affect the dependent variable. It showed that current speed and direction were the most important variables for drift speed and direction, with values of 47.1% and 58.1%, respectively. The analysis showed that the statistical values indicated the fit of the model at the significance level of 0.05 for multiple regression analysis. The multiple correlation coefficients indicating the degree of influence on the dependent variable were 83.2% and 89.0%, respectively. The determination of coefficients were 69.3% and 79.3%, and the adjusted determination of coefficients were 67.6% and 78.3%, respectively. In this study, a more quantitative prediction model will be presented because it is performed after identifying outliers and influence points of sample data before multiple regression analysis. Therefore, many studies will be active in the future by combining them.
        4,600원
        36.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        After the United Nations Convention on the Law of the Sea (UNCLOS) and the United Nations Fish Stocks Agreement (UNFSA) came into effect, international cooperation through Regional Fisheries Management Organizations (RFMOs) was required, and each RFMO established and adopted the Conservation and Management Measure (CMM) for the regional Observer Programs to collect data on fishing activities and biological information and to monitor compliance with its CMMs. The observer coverage required by RFMO is set differently for each organization, ranging from 5% to 100%. In addition, tuna-RFMOs recommend increasing observer coverage in longline fisheries by at least 20% for reliable quantitative analysis of not only target species but also bycatch species and ecologically related species such as sharks, seabirds, sea turtles, and marine mammals. Therefore, in this study, we discussed ways to improve the national observer programs of Korean distant water fisheries that should be addressed in the future to respond to the RFMO trends.
        4,000원
        37.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        금(金, 1115~1234)이 적극적으로 시행했던 관영수공업 체제와 정책에 주목해 금대 동 경(銅鏡)의 새로운 경향과 특징을 고찰하였다. 금에서는 요, 송계로 구분할 수 있는 전통적 인 양식뿐 아니라 이를 바탕으로 폭포, 나무, 암석, 누각 등을 이용해 회화적인 화면구도로 재구성한 금계 동경들이 제작되었다. 원근법과 상하 구도를 적용한 화면 구성이 거울의 한정 된 공간 속에 적용되었고, 마치 한 폭의 그림처럼 선경의 세계를 표현하거나 관폭도와 같이 떨어지는 폭포를 바라보는 장면들이 동경에 표현되었다. 이러한 특징은 12세기 초부터 금의 수도가 세워졌던 상경성 내지(지금의 黑龍江省 阿城 부근)의 관영 공방을 중심으로 제작되 었다. 금 초기부터 관영수공업 체제에서 동경의 주원료인 구리의 원활한 수급을 위해 동경을 제작하였고 동원(銅院), 경자국(鏡子局), 주경소(鑄鏡所)와 같은 관서를 별도로 조직해 체 계적으로 동경을 제작 및 관리하는 정책을 시행하였다. 한편 중앙관청 중에도 공예품의 제작 과 장인의 운영을 담당했던 소부감과 관련이 있고, 그중에서도 금속공예품의 도안을 담당했 던 도화서 소속의 장인과도 관련이 있을 것으로 파악되었다. 금 정부는 실력 있는 외부 장인 들을 정책적으로 상경성에 집중시켰다. 여진의 토착문화와 기타 여러 민족의 외래문화가 상 경성 내지를 중심으로 흡수 및 통합되면서 금만의 새로운 동경들이 제작될 수 있었다.
        6,600원
        38.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The towing distance, which is speed over the ground, and the water flow quantity, which is speed through the water, were used when estimating the amount of Metapenaeus joyneri resources that rose to the surface at night using the swept area method in order to compare and analyze the difference. It was conducted using a shrimp dredge, trial fishing gear for catching Metapenaeus joyneri. Catch during the entire survey period was 188.9 kg. Monthly catch ranged from 3.1 to 109.2 kg, highest in June and lowest in September. The swept volume calculated using the speed over the ground was about 13% higher than using the speed through the water. Metapenaeus joyneri resources estimated using the towing distance ranged from 320.1 to 14,649.8 kg. Resources estimated using the water flow quantity ranged from 278.5 to 12,886.3 kg. Therefore, the amount of Metapenaeus joyneri resources estimated using the speed over the ground was about 14% higher than the method using the speed through the water, indicating that the amount of resources was overestimated.
        4,000원
        39.
        2024.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Al2O3 has excellent sintering properties and is important in semiconductor manufacturing processes that require high-temperature resistance and chemical inertness in a plasma environment. In this study, a comprehensive analysis of the chemical characteristics, physical properties, crystal structure, and dispersion stability of three commercially available Al2O3 powders was conducted. The aim was to provide a technological foundation for selecting and utilizing appropriate Al2O3 powders in practical applications. All powders exhibited α-Al2O3 as the main phase, with the presence of beta-phase Na2O-11Al2O3 as the secondary phase. The highest Na+ ion leaching was observed in the aqueous slurry state due to the presence of the secondary phase. Although the average particle size difference among the three powders was not significant, distinct differences in particle size distribution were observed. ALG-1SH showed a broad particle size distribution, P162 exhibited a bimodal distribution, and AES-11 displayed a uniform unimodal distribution. Highconcentration Al2O3 slurries showed differences in viscosity due to ion release when no dispersant was added, affecting the electrical double-layer thickness. Polycarboxylate was found to effectively enhance the dispersion stability of all three powders. In the dispersion stability analysis, ALG-1SH exhibited the slowest sedimentation tendency, as evidenced by the low TSI value, while P162 showed faster precipitation, influenced by the particle size distribution.
        4,000원
        40.
        2024.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        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.
        4,000원
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