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        검색결과 379

        1.
        2024.04 구독 인증기관·개인회원 무료
        The recent increase in the occurrence of common bed bug and tropical bed bug in shared areas highlights the need for rapid species identification at infestation sites, which is crucial for implementing targeted control measures due to differences in genetic and physiological traits. In this study, molecular diagnostic methods were developed using species-specific ITS2 sequences. Both multiplex PCR and loop-mediated isothermal amplification (LAMP) protocols with a DNA release method successfully distinguished between the two bed bug species regardless of developmental stages in 0.5~2.5 hours, even with dead specimens. Especially, LAMP's simplicity and speed make it applicable for rapid and accurate bed bug diagnosis at infestation sites.
        2.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The emergence of ferrous-medium entropy alloys (FeMEAs) with excellent tensile properties represents a potential direction for designing alloys based on metastable engineering. In this study, an FeMEA is successfully fabricated using laser powder bed fusion (LPBF), a metal additive manufacturing technology. Tensile tests are conducted on the LPBF-processed FeMEA at room temperature and cryogenic temperatures (77 K). At 77 K, the LPBF-processed FeMEA exhibits high yield strength and excellent ultimate tensile strength through active deformation-induced martensitic transformation. Furthermore, due to the low stability of the face-centered cubic (FCC) phase of the LPBFprocessed FeMEA based on nano-scale solute heterogeneity, stress-induced martensitic transformation occurs, accompanied by the appearance of a yield point phenomenon during cryogenic tensile deformation. This study elucidates the origin of the yield point phenomenon and deformation behavior of the FeMEA at 77 K.
        4,000원
        3.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Korean melon (Cucumis melo L.) is an environment in which most farming work can affect the increase in musculoskeletal diseases, and the stems are attracted to the ground in order to grow no-heating cultivation. In this study, growth and productivity were compared according to the type of high-bed. The narrower the surface area at the bottom of the high-bed, the faster the initial growth, which was advantageous. The bed is which the height if 70 cm, the surface temperature has risen due to the increase in direct solar radiation inflow since April, requiring side light blocking to block the inflow of solar radiation. In terms of fruit quality, the 200 cm width treatment had higher fruit sugar content and better hardness than the 160 cm treatment. From April to September, the total yield was 6.8 kg/plant of treatment A, 8.7 kg/plant of treatment B, 5.8 kg/plant of treatment C, treatment B mainly 50% higher than treatment C, and 27% higher than treatment A. Therefore, the bed form suitable for Korean melon high bed is 200 cm wide, 40 cm high between the surface and the bed, and the surface of the passage between the beds is 30cm high from the ground to the bed.
        4,000원
        4.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the effect of crown heating on the cultivation environment, budding, flowering and yields of strawberry was analyzed. In December, January, and February, when the outside temperature was low, the average strawberry crown temperature at daytime in the test zone was 1.3°C higher than that in the control zone, and the average strawberry crown temperature at nighttime in the test zone was 2.7°C higher than that in the control zone. The average bed temperature at daytime in test zone was 1.7°C higher than that in the control zone, and the average bed temperature at nighttime in test zone was 2.4°C higher than that in the control zone. As a result of performing correlation analysis and regression analysis on strawberry crown temperature and budding period, the correlation coefficient was -0.86, which tended to be shorter as the crown temperature was higher, and the determination coefficient was 0.74. The total yields of strawberry during test period were 392.6 g/plant for test greenhouse and 346.0 g/plant for control greenhouse respectively. As for the quality of strawberries, the ratio of 2L (very large) grades and L (large) grades was 62.4% in the test greenhouse and 58.5% in the control greenhouse, indicating that the proportion of high quality strawberries was higher in the test greenhouse.
        4,000원
        5.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, machine learning models are proposed to predict the Vickers hardness of AlSi10Mg alloys fabricated by laser powder bed fusion (LPBF). A total of 113 utilizable datasets were collected from the literature. The hyperparameters of the machine-learning models were adjusted to select an accurate predictive model. The random forest regression (RFR) model showed the best performance compared to support vector regression, artificial neural networks, and k-nearest neighbors. The variable importance and prediction mechanisms of the RFR were discussed by Shapley additive explanation (SHAP). Aging time had the greatest influence on the Vickers hardness, followed by solution time, solution temperature, layer thickness, scan speed, power, aging temperature, average particle size, and hatching distance. Detailed prediction mechanisms for RFR are analyzed using SHAP dependence plots.
        4,000원
        6.
        2023.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Ti-6Al-4V lattice structure is widely used in the aerospace industry owing to its high specific strength, specific stiffness, and energy absorption. The quality, performance, and surface roughness of the additively manufactured parts are significantly dependent on various process parameters. Therefore, it is important to study process parameter optimization for relative density and surface roughness control. Here, the part density and surface roughness are examined according to the hatching space, laser power, and scan rotation during laser-powder bed fusion (LPBF), and the optimal process parameters for LPBF are investigated. It has high density and low surface roughness in the specific process parameter ranges of hatching space (0.06–0.12 mm), laser power (225–325 W), and scan rotation (15°). In addition, to investigate the compressive behavior of the lattice structure, a finite element analysis is performed based on the homogenization method. Finite element analysis using the homogenization method indicates that the number of elements decreases from 437,710 to 27 and the analysis time decreases from 3,360 to 9 s. In addition, to verify the reliability of this method, stress–strain data from the compression test and analysis are compared.
        4,000원
        7.
        2023.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Although the Ti–6Al–4V alloy has been used in the aircraft industry owing to its excellent mechanical properties and low density, the low formability of the alloy hinders broadening its applications. Recently, laser-powder bed fusion (L-PBF) has become a novel process for overcoming the limitations of the alloy (i.e., low formability), owing to the high degree of design freedom for the geometry of products having outstanding performance used in hightech applications. In this study, to investigate the effect of bulk shape on the microstructure and mechanical properties of L-PBFed Ti-6Al-4V alloys, two types of samples are fabricated using L-PBF: thick and thin samples. The thick sample exhibits lower strength and higher ductility than the thin sample owing to the larger grain size and lower residual dislocation density of the thick sample because of the heat input during the L-PBF process.
        4,000원
        8.
        2023.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : Advancements in science and technology caused by industrialization have led to an increase in particulate matter emissions and, consequently, severity of air pollution. Nitrogen oxide (NOx), which accounts for 58% of road transport pollutants, adversely affects both human health and the environment. A test-bed was constructed to determine NOx removal efficiency at the roadside. TiO2, a material used to reduce particulate matter, was used to remove NOx. It was applied to a vertical concrete structure using the dynamic pressurized penetration TiO2 fixation method, which can be easily applied to vertical concrete structures. This study was conducted to evaluate the NOx removal efficiency of the dynamic pressurized-penetration TiO2 fixation method in a test-bed under real roadside conditions. METHODS : A test-bed was constructed in order to determine the NOx removal efficiency using the dynamic pressurized penetration TiO2 fixation method on the roadside. The dynamic pressurized-penetration TiO2 fixation method was applied by installing a vertical concrete structure. NOx was injected into the test-bed using an exhaust gas generator. By installing a shading screen, the photocatalytic reaction of TiO2 was suppressed to a maximum concentration of 1000 ppb along the roadside. The removal efficiency was evaluated by measuring NOx concentrations. In addition, illuminance was measured using an illuminance meter. RESULTS : From the results of the analysis of the NOx removal efficiency in the test-bed which the dynamic pressurized type TiO2 fixation method was applied to, an average removal efficiency ranging from 18% to 40% was achieved, depending on the illuminance. Similarly, according to the results of the evaluation of the NO removal efficiency, an average of removal efficiency ranging from 20% to 62% was achieved. Thus, the NOx removal efficiency increased when the illuminance was high. CONCLUSIONS : From the results of the experiment conducted, the efficiency of NOx removal per unit volume was obtained according to the illuminance of TiO2 concrete along an actual road. Field applicability of the dynamic pressurized-penetration-type TiO2 fixation method to vertical concrete structures along roads was confirmed.
        4,000원
        9.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Technological developments have led to the creation of a mechanical device capable of providing a representative massage as a passive treatment. The use of mechanical massage offers the distinct advantage of being user-friendly and available for use at any given time. Objectives: To investigated present the outcomes of utilizing a massage bed on the range of motion (ROM) and pressure pain threshold (PPT) in patients diagnosed with chronic low back pain. Design: ABA design of a single case study. Methods: To measure the ROM of the subject's trunk flexion, extension, lateral flexion, and rotation, a tape measure and goniometer were utilized. Furthermore, PPT was measured using an electronic pressure pain meter. Baseline A and Baseline A’ periods were conducted for 5 consecutive days without intervention. Following the baseline periods, a massage bed intervention was administered for 1 hour daily for a total of 10 days during the Intervention B period. Daily assessments were performed, and the Intervention B period was conducted after the intervention. Results: The ROM effect was confirmed in trunk lateral flexion and rotation, while the PPT was effective in both L1, right L2, left L4, and left L5. Conclusion: The results of this study confirmed that the use of a massage bed improved the ROM and PPT in patients suffering from chronic back pain. Further randomized controlled trials involving a larger sample size are necessary to validate these findings.
        4,000원
        11.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently 3d printer industry has two demands. first is color 3d printing. second is mass production using 3d printer that has large bed. According to previous studies, 3D printed objects have different weights depending on filament colors. 3D printed tensile specimens with filaments of various colors were checked to see they had the same weight. If so, we wanted to see it was statistically significant. As a result, we found that the weight of 3D printed objects was statistically significantly different depending on the filament color. The average weight of 3d printed objects is: Black(8.63g), Blue(8.58g), Yellow(8.53g), White(8.48g), Natural(8.46g), Green (8.45g), Red(8.42g).
        4,000원
        12.
        2022.12 구독 인증기관 무료, 개인회원 유료
        이 연구는 영국의 미술가 트레이시 에민(Tracey Emin, 1963 ~ )의 〈나의 침대〉 를 다룬다. 〈나의 침대〉는 에민이 이성과의 이별 후 나흘간 머물렀던 그의 침대를 전 시실로 옮겨 놓은 것으로, 매트리스와 프레임으로 구성된 하나의 침대와 침대 주변에 다양한 오브제를 배치한 작품이다. 에민의 작업은 주로 그의 사적 생활과 감정을 주 제로 삶을 이야기하며, 그가 겪어온 삶과 밀접하게 연관되어 있다.〈나의 침대〉에는 에민의 불안정한 인간관계뿐만 아니라 삶의 고통이 드러난다. 〈나의 침대〉에는 모성 의 상실이 드러나거나 임신에 대한 두려움과 이별에 대한 고통과 불안감, 슬픔을 나 타난다. 에민은 〈나의 침대〉에서 그의 상처와 고통을 숨김없이 표현하였고, 그의 혼 란과 고통을 고백하는 행위를 통해 카타르시스를 경험하며 치유의 순간으로 전환된 다. 에민이 작업 과정에서 갖게 되는 치유의 경험은 관람자에 전달되며 상호 관계적 소통의 단계로 나아가게 된다. 본 연구자는 에민이 〈나의 침대〉를 통해 자신의 상처 를 어떻게 치유하는가의 과정을 연구할 것이다.
        5,100원
        13.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The SLA 3d printer is the first of the commercial 3D printer. The 3D printed output is printed hanging on the bed that move to the upper position. Sandblasted bed is used to prevent layer shift. If sandblasting is wrong, the 3D printed output is layer shifted. For this reason, 3D printer manufacturing companies inspect the bed surface. However, the sandblasted surface has variety of irregular shapes and craters, so it is difficult to establish a quality control standard. To solve problems, this paper presents a standardized sandblasting histogram and threshold. We present a filter that can increase the classification rate.
        4,000원
        14.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, considerable attention has been given to nickel-based superalloys used in additive manufacturing. However, additive manufacturing is limited by a slow build rate in obtaining optimal densities. In this study, optimal volumetric energy density (VED) was calculated using optimal process parameters of IN718 provided by additive manufacturing of laser powder-bed fusion. The laser power and scan speed were controlled using the same ratio to maintain the optimal VED and achieve a fast build rate. Cube samples were manufactured using seven process parameters, including an optimal process parameter. Analysis was conducted based on changes in density and melt-pool morphology. At a low laser power and scan speed, the energy applied to the powder bed was proportional to and not . At a high laser power and scan speed, a curved track was formed due to Plateau-Rayleigh instability. However, a wide melt-pool shape and continuous track were formed, which did not significantly affect the density. We were able to verify the validity of the VED formula and succeeded in achieving a 75% higher build rate than that of the optimal parameter, with a slight decrease in density and hardness.
        4,000원
        15.
        2022.10 구독 인증기관·개인회원 무료
        Radionuclides stored in a radioactive waste repository over a long period of time might be leached through the barriers such as engineered rock (cement) and natural rock (granite). Organic complexing agents such as ethylenediaminetetraacetic acid (EDTA) and isosaccharinic acid (ISA) may also influence the mobility of radionuclides. In this study, a continuous fixed-column reactor packed with engineered and natural rocks was designed to investigate the effect of organic complexing agents on cesium mobility through cement and granite under anaerobic conditions. The influent flow rate of the mixed solution (organic complexing agent and cesium) at the column bottom was 0.1 mL/min, while that of groundwater was 0.2 mL/min, which was introduced between cement and granite layers in the middle of the column. The hydraulic properties such as diffusion coefficient and retardation factor were derived by a bromide tracer test. The effects of different operating parameters, such as initial cesium concentrations, initial EDTA or ISA concentrations, and bed size, on the cesium adsorption were investigated. The Thomas, Adams-Bohart, and Yoon-Nelson models were applied to the experimental data to predict the breakthrough curves using non-linear regression. These results suggest that organic complexing agents such as EDTA and ISA significantly influence the mobility of cesium in the barriers, indicating that the presence of complexing agents enhances the migration of cesium to the geosphere.
        17.
        2022.10 구독 인증기관·개인회원 무료
        The damaged spent fuel rods must be stabilized by encapsulation or dry re-fabrication technologies before geological disposal. For applying the dry re-fabrication technology, we manufactured a vertical type furnace to perform both fuel material recovery from damaged fuel rods by oxidative decladding and sinterability improvement of fuel powder by repetition of oxidative and reaction treatment. A horizontal type furnace provides only a diffusion-controlled reaction resulting in longer reaction time and decreasing amount of powder for oxidation and reduction, whereas a vertical type furnace with a submerged gas distributor gives rapid reaction due to flowing gas-solid contact by fluidization. For observation of fluidization behaviors of uranium oxides at room temperature, fluidized column was prepared with transparent cylindrical tube, pressure transmitter and gas flow meter. Number of size of orifice holes was determined by equations in Fluidization Engineering [D.Kunii, O. Levenspiel]. Before uranium oxide test, as surrogates, WO2 (10.8 g/cm3) and Ta2O5 (8.2 g/cm3) powder similar to density of UO2 (10.96 g/cm3) and U3O8 (8.3 g/cm3), respectively were used to achieve fluidization operation conditions in the region from minimum to expanded fluidization. Fluidization behaviors and pressure drop of powder bed was observed according to operation parameters such as gas velocity, number and size of orifice holes, and powder amount.
        18.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 딸기 온실 내부의 방대한 환경인자를 활용하여 판별분석을 실시하고 딸기의 재배 베드 단수에 따른 온실 내부의 환경인자를 분석함으로 써, 딸기 분야에서 계측된 데이터의 활용성을 높이기 위한 기초자료로 활용할 목적으로 수행하였다. 그 결과는 다음과 같다. 환경인자별(온도, 습도, 이산화탄소 농도, EC 및 pH) 동질성 검정의 유의확률은 각각 0.0001, 8.2788E-38, 4.3310E-85, 1.3001E-16 및 0.0001로서 설정한 유의수준 0.05보다 낮게 나타났다. 그리고 분석결과 판별함수식은 F(x)1 = –60.5664 -0.1339×Temperature –0.0087×Humidity +0.0018×CO2 +0.1014×EC +8.3860×pH, F(x)2 = –12.4928 +0.1963×Temperature –0.0024×Humidity +0.0254×CO2 –0.0187×EC –0.3651×pH로 도출되었다. 판별함수식의 정확도는 대상 온실 A (81.1%) 및 B (96.1%)보다 대상 온실 C (100.0%)에서 높은 것으로 나타났다. 예측 가능한 대상 온실별(A, B 및 C) 분류함수는 각각 – 1836.7035 – 2.8733×Temperature + 0.1355×Humidity + 0.4186×CO2 + 7.4351×EC + 484.5901×pH, – 1710.8369 – 2.7701×Temperature + 0.1550×Humidity + 0.3937×CO2 + 7.2482×EC + 468.1477×pH, – 2291.7125 - 3.9756×Temperature + 0.0723× Humidity + 0.4177×CO2 + 8.1961×EC + 546.8476×pH로 나타났다. 특히 판별함수식을 근거로 환경인자별 새로운 측정값이나 자료를 입력하였을 때, 특정 그룹으로 분류가 가능함으로써 데이터의 특징을 파악할 수 있다. 이러한 환경인자는 식별을 용이하게 함으로써 환경인자 측정값의 활용도를 높여주는 방법이라고 판단된다.
        4,000원
        20.
        2022.05 구독 인증기관·개인회원 무료
        The cyber-attack on Natanz nuclear facility in Iran which called Stuxnet showed how cyber could affect the physical system. If cyber-attack on NPPs compromise digital I&C system, it may occur some malfunction on actuators and at worst, radioactive material released into the environment. However, it is hard to test the cyber security on operating NPPs because of the safety problems. So, it is necessary to develop a test-bed to test both the cyber security of NPPs and the effect of cyber-attack on NPPs. KINAC has been developing NPPs test-bed to evaluate the cyber security of NPPs, validate cyber security controls of licensee and train the inspectors. In this paper, the conceptual design of NPPs cyber security test-bed will be discussed. Actual I&C systems such as PLC (Programmable Logic Controller) and DCS (Distributed Control System) are essential for testing cyber security. Also, NPPs simulator is one of important part to evaluate or analyze the effect of cyber-attack on NPPs. Usually, NPPs simulator consists of software which contains nuclear model, thermal-hydraulic model, execution program and GUI and hardware which contains workstation, operator console, PC and large display panel. It provides very similar to actual NPPs to users. However, in case of conventional NPPs simulator, I&C part is implemented as a software, so it is impossible to test the cyber security. To solve this issue, in case of the NPPs cyber security test-bed, I&C part should be hardware and simulation code should be modified to connect the hardware I&C part and software simulator using the HIL (Hardware-in-the-loop) method. The main purpose of this NPPs cyber security test-bed is to utilize in NPPs cyber security regulation. So, KINAC is developing the test-bed with APR 1400 simulator model and KNICS PLC and DCS platform. These real hardware I&C system will be connected to hacker’s PC to test cyber security of NPPs. Also, the data set will be updated with real NPPs data set after the test-bed development finished. Furthermore, to give various analysis environment, archiving equipment that archive major plant process data, network packet between I&C systems and the like will be added. This NPPs cyber security test-bed combined the good points of conventional NPPs simulator and cyber security test-bed. It can test the cyber security of NPPs that conventional NPPs simulator cannot do. Also, it can evaluate and analyze the impact of cyber-attack on NPPs that cyber security test-bed cannot do.
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