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        검색결과 685

        2.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 국내의 세 품종 돼지에 대하여 혈통자료를 이용한 근교계수와 유전체자료를 이용한 근교계수를 분석하고 비교하기 위하여 수행되었다. 분석에 이용된 혈통자료는 듀록, 랜드레이스 및 요크셔 종에서 각각 137,302두, 228,651두와 657,079두였고, 유전체자료의 경우 Illumina Porcine SNP 60K bead chip V2를 이용하여 수집하였으며 세 품종에서 각각 2,567개, 7,594개 및 12,906개의 자료를 이용하였다. 듀록, 랜드레이스와 요크셔에서 혈통자료를 이용하여 추정된 근교계수는 각각 0.04, 0.02 및 0.02였으며, 유전체자료를 이용하여 추정된 근교계수는 각각 0.184, 0.098 및 0.063이었다. 듀록에서 두 근교계수의 상관이 0.466으로 가장 높게 나타났다. 본 연구를 통하여 혈통완성도는 유전체 정보를 이용하여 보완할 수 있음이 확인되었으며, 유전체 정보는 집단의 유전자원 관리에도 활용도가 높아 국내 양돈산업의 근친도 관리에서 중요한 역할을 할 것으로 기대된다.
        4,000원
        3.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : Concrete, which is a construction material, is the most widely used compression material; however, unlike steel, it exhibits nonlinear material characteristics. Therefore, to examine the behavior of structures under the nonlinear conditions of concrete materials, one must select an appropriate numerical-analysis technique and a reasonable material model. When performing the nonlinear numerical analysis of a structure using general-purpose structural analysis software, the stress–strain curve or the Mohr–Coulomb failure criterion is typically employed to consider the nonlinear material characteristics. In this study, an efficient nonlinear numerical analysis is conducted by defining the stress–strain curves and Mohr–Coulomb parameters applicable to Strand7 to examine and design the stability of reinforced concrete structures. METHODS : This study was conducted by improving existing data. Based on the tensile region of the concrete stress–strain curve presented in a simple shape and the results of the splitting test, the proposed Mohr–Coulomb parameter was improved based on regulations stipulated in the design standards of concrete structures. The characteristics and usability of the improved material models were examined using concrete splitting tensile and bending models. RESULTS : A yield area distribution similar to that of the reference data is obtained when the Mohr–Coulomb material model is used in the numerical analysis of the concrete splitting tension, thus confirming the validity of the model. In the Mohr–Coulomb material model, nonlinear resistance continues even after the maximum reaction force occurs. However, when the stress–strain curve material model is applied, at the moment the maximum reaction force occurs, the material yields and begins to be damaged. In addition, by applying the Mohr–Coulomb material model to the bending numerical-analysis model, the magnitude of stress in the tensile region from the initial stage exceeds the yield stress defined in the stress–strain curve. CONCLUSIONS : Based on a series of examples, the usability of the proposed concrete stress–strain curve and Mohr–Coulomb parameters is confirmed. However, to obtain numerical-analysis results that are consistent with the nonlinear behavior of actual structures, nonlinear testing of reinforced concrete structures shall be conducted and material models shall be improved.
        4,000원
        4.
        2024.04 구독 인증기관·개인회원 무료
        We investigated the effects of fluctuating temperature on development and fertility of M. persicae at different temperature conditions, 10, 15, 20, 25, 28, and 30±5℃, respectively. In this study, we collected detailed data on development periods, and fertility of M. persicae at six different temperatures. We analyzed the life table parameters of M. persicae using age-stage, two-sex life table program. The intrinsic and finite rate of increase were the highest at 25±5℃. The fertiltiy was the highest at 20±5℃.
        5.
        2024.04 구독 인증기관·개인회원 무료
        Riptortus pedestris is known to acquire their symbiotic bacteria, Caballeronia insecticola, from soil environments in every generation. The symbionts have been demonstrated to affect behavioral and physiological traits of the host insect such as the enhancement of development. In particular, symbiotic effects on female adults could directly entail changes in their population growth. Therefore, we investigated a suite of symbiotic effects of C. insecticola on behaviors and fitness-related parameters of female R. pedestris. Overall, symbiotic females showed an behavioral enhancement in both feeding efficacy and movement capacity including walking and flight. In addition, the survival rates under exposure to overwintering conditions and insecticide resistance level were significantly higher in symbiotic females than the aposymbiotic. Finally, although symbiotic females exhibited shorter longevity, their fecundity was found higher compared to the apo-symbiotic.
        6.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : In this study, an empirical approach was established to estimate the parameters of the resilient modulus based on various geotechnical properties of subgrade soils. METHODS : Multiple regression analyses were performed to analyze the relationship between resilient modulus (k1) and deformation. The most important factors are the #200 sieve passing ratio, moisture content, and dry unit weight of the soil. The applicability of this approach was verified using selected field data and the literature. RESULTS : The correlation between the results predicted using the prediction equation of the model constant (k1) and the actual k1-value was high. The applicability of the prediction equation was considered high owing to its high suitability with the existing data. The range of values obtained using the constant prediction equation of the proposed model was also judged to be reasonable. In the comparison of the CBR value of the subgrade material of the actual design section and the predicted elastic modulus (k1), almost no relationship was observed between the CBR and the model coefficient (k1). Thus, the estimation of the elastic modulus through CBR is likely to contain errors. CONCLUSIONS : Based on these results, the parameters of the universal model can be predicted using the stress-dependent modulus model proposed in this study.
        4,000원
        7.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Stroke patients experience a variety of physical problems due to neurological problems, including difficulties with trunk control. Trunk taping is used to improve gait in stroke patients. Objectives: To investigated the immediate effect of thoracic and abdominal elastic taping on gait parameters (the dynamic balance and gait speed) in stroke patients. Design: Quasi experimental study. Methods: A total of 24 study subjects were randomly assigned to the experimental group (thoracic and abdominal taping, 12 people), and the control group (sham taping, 12 people). All subjects had timed up and go (TUG) test and 10 meter walk test (10MWT) measured before and after taping. Results: After taping, the TUG test and 10MWT results were significantly reduced only in the study group (P<.05). The TUG test and 10MWT results of the study group were significantly decreased compared to the control group. Conclusion: The thoracic and abdominal taping was found to improve trunk control in stroke patients, thereby improving dynamic balance and walking speed.
        4,000원
        8.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: In community-dwelling elderly individuals, slower gait speed is closely related to the ground reaction force. In the elderly with fall experience, stride length and gait speed, and other gait parameters are closely related to gastrocnemius activation. Objectives: To investigate whether medial gastrocnemius stiffness influences gait parameters in community-dwelling elderly people who experienced falls. Design: Cross sectional study. Methods: A total of 149 community-dwelling older adults were assigned to the faller and non-faller groups. Gait parameters (step length, stride length, step width, cadence, heel and toe ground reaction force, heel and toe contact time), and stiffness of the medial and lateral gastrocnemius and tibialis anterior were measured using shear wave elastography. Results: Elderly fallers had shorter step and stride length, lower cadence and toe ground reaction force and heel contact time, and lower medial gastrocnemius stiffness than non-fallers. In elderly fallers, medial gastrocnemius stiffness was significantly correlated with step and stride length, step width, toe ground reaction force, and heel contact time. Conclusions: Lower medial gastrocnemius stiffness in the elderly fallers decreases gait parameters, which can be a risk factor for falls. Therefore, medial gastrocnemius stiffness is a major factor that may associated gait parameters that can determine the risk of fall in community-dwelling elderly individuals.
        4,000원
        9.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this research, the marine medaka Oryzias javanicus underwent a 96 h exposure to two concentrations of the red tide dinoflagellate Karenia mikimotoi (1,000 and 5,000 cells mL-1), and the temporal variations in biochemical responses related to antioxidant and immunity parameters were assessed in the liver tissue. The study revealed a significant increase in ichthyotoxicity with elevated cell concentrations of K. mikimotoi, especially evident at 96 h in marine medaka exposed to 5,000 cells mL-1. At 1,000 cells mL-1 of K. mikimotoi, the opercular respiratory rate showed a significant increase, whereas exposure to 5,000 cells mL-1 resulted in a lowered rate. The intracellular malondialdehyde content was significantly elevated in response to both cell concentrations at 96 h. Regarding glutathione content, levels were significantly increased by exposure to both cell concentrations. Catalase and superoxide dismutase enzymatic activities experienced an increase at 1,000 cells mL-1 of K. mikimotoi, while their activities were reduced at 5,000 cells mL-1 at 96 h. The analysis of two immunity parameters, alternative complement pathway and lysozyme, demonstrated significantly reduced activities in the liver tissue exposed to 5,000 cells mL-1 of K. mikimotoi. These findings aim to enhance the understanding of K. mikimotoi toxicity in marine fish by offering insights into biochemical responses associated with harmful algal blooms.
        4,000원
        10.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        압축센스(Compressed SENSE) 기법은 검사 시간을 획기적으로 단축할 수 있으나, 시간 단축을 위한 기법적용 시 가속계수를 증가시키면 인공물의 발생이 영상에서 증가하는 문제점이 있다. 이에 인공물이 발생하지 않으면서 검사 시간을 최대한 단축할 수 있는 최적의 압축센스 가속계수를 제시하고자 하였다. 연구 방법은 인공물이 발생하지 않는 가속계수 1.0을 기준으로 0.5 간격씩 5.0까지 무릎관절 자기공명영상의 팬텀 실험과 임상실험 영상을 획득한 후, 방사선사 10명이 5점 척도로 영상을 평가하여 유의한 차이가 있는지 판단하였다. 연구 결과 T1 강조영상과 T2 강조 영상 모두 팬텀 실험은 가속계수 2.0 이하로 하였을 때 임상실험은 3.0 이하로 하였을 때 기준이 되는 1.0 영상과 차이가 없었다. 결론적으로 무릎관절 자기공명영상 검사 시 인공물이 발생하지 않으며 검사 시간을 최대로 단축할 수 있는 최적의 압축센스 가속계수는 팬텀 실험의 경우 2.0, 임상실험의 경우 3.0이 적정하리라 판단된다.
        4,200원
        11.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        European and Turkish rice varieties were analysed to identify the traits associated with low-temperature germination. The aim of the study is to develop new rice varieties that can use these traits to reduce greenhouse gas emissions in rice fields. The average low temperature germination ratio (GR) in the European and Turkish rice varieties was 89.0±14.1%. The speed of the germination rate (SG) in Korean early maturing varieties, ‘Jopyeong’ and ‘Baekilmi’ was 1.3 and 3.5, respectively, whereas the European and Turkish varieties had a SG of 6.6. In terms of germination energy (GE) by the date, the European and Turkish varieties started germination within 4 days, while ‘Jopyeong’ and ‘Baekilmi’ began to germinate after 8 and 10 days, respectively. The mean germination time (MGT) for the European and Turkish varieties was 9.9±1.2 days. Between 4 to 10 days after inoculation, the germination velocity coefficient (GVC) for the European and Turkish varieties increased moderately from 2.6 to 5.3. After 10 days, the GVC rose rapidly from 7.0 to 12.0. ‘Jopyeong’ and ‘Baekilmi’ had slower germination rates compared to the European and Turkish varieties, in which the GVC increased moderately to 3.2 and 2.3, respectively, between 7 and 9 days after inoculation. The average mesocotyl elongation ability was 4.0±0.4 cm, with a range from 1.3 cm to 7.3 cm.
        4,000원
        12.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        수인성 질산 노출에 대한 향어의 독성 영향을 확인하기 위해 96시간 동안 0, 4, 20, 100, 500 및 2,500 mg NO3 -/L의 수인성 질산에 노출을 실시하였다. 질산 96시간 급성 노출에 의한 향 어의 반수치사농도(LC50)는 1,433.54 mg NO3 -/L로 나타났다. 혈액학적 성상을 통해 수인성 질 산 노출이 향어에게 미치는 생리학적 변화를 평가하였으며, RBC count는 유의적인 감소를 나 타내었다(p < 0.05). 혈장 무기성분을 통해 수인성 질산 노출에 따른 향어의 이온 조절 능력 변화를 평가하였으며, 혈장 무기성분에서 calcium과 magnesium은 유의적으로 감소하였다(p < 0.05). 혈장 유기성분을 통해 수인성 질산 노출로 인한 향어의 건강도와 스트레스 상태를 평 가하였으며, 혈장 유기성분인 glucose는 유의적인 증가를 나타내었다(p < 0.05). 혈장 효소성분 을 통해 수인성 질산 노출로 인한 간 손상도 및 효소 활성의 변화를 평가하였으며, 혈장 효소 성분인 AST, ALT 및 ALP는 높은 수준의 수인성 질산 노출에서 유의적으로 감소하였다(p < 0.05). 본 연구의 결과는 C. carpio nudus에 대한 수인성 질산 노출이 생존율, 혈액학적 성상 및 혈장성분에 독성으로 영향을 미칠 수 있음을 의미한다.
        4,000원
        13.
        2023.11 구독 인증기관·개인회원 무료
        Once decommissioning begins, it is expected that large amount of radioactive wastes will be produced in a short period of time. The expected amount of radioactive wastes from Kori unit 1 NPP are approximately 80,000 drums (base on 200 L). By minimizing the amount of radioactive wastes generated through decontamination and reduction, KHNP has set the final target for the amount of radioactive wastes to be delivered to the disposal site at approximately 14,500 drums. Here, plasma torch melting technology is an essential technology for radioactive wastes treatment during nuclear power plants decommissioning and operation, because of its large volume reduction effects and the diversity of disposable wastes. KEPCO KPS was able to secure experience in operating Plasma Torch Melter (PTM) by conducting a research service for ‘development of plasma torch melting system advancement technology’ at KHNP-CRI. This study will compare kilo and Mega-Watt class PTM, largely categorized into facility configurations, operating parameters, and waste treatment. Based on this study, it would be desirable to operate PTM with approximate capacity according to the frequency and amount of waste production, and suggest volume for a kilo and Mega-watt class plasma torch in the melting furnace respectively. This plays to its strengths for both a kilo and Mega-watt class PTM.
        14.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The demand for high-strength steel is rising due to its economic efficiency. Low-cycle fatigue (LCF) tests have been conducted to investigate the nonlinear behaviors of high-strength steel. Accurate material models must be used to obtain reliable results on seismic performance evaluation using numerical analyses. This study uses the combined hardening model to simulate the LCF behavior of high-strength steel. However, it is challenging and complex to determine material model parameters for specific high-strength steel because a highly nonlinear equation is used in the model, and several parameters need to be resolved. This study used the particle swarm algorithm (PSO) to determine the model parameters based on the LCF test data of HSA 650 steel. It is shown that the model with parameter values selected from the PSO accurately simulates the measured LCF curves.
        4,000원
        16.
        2023.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The thermal integrity of spent nuclear fuels has to be maintained during their long-term dry storage. The detailed temperature distributions of spent fuel assemblies are essential for evaluating the integrity of their dry storage systems. In this study, a subchannel analysis model was developed for a canister of a single fuel assembly using the COBRA-SFS code. The thermal parameters affecting the peak cladding temperature (PCT) of the spent fuel assembly were identified, and sensitivity analyses were performed based on these parameters. The subchannel analysis results indicated the presence of a recirculation flow, based on natural convection, between the fuel assembly and downcomer region. The sensitivity analysis of the thermal parameters indicated that the PCT was affected by the emissivity of the fuel cladding and basket, convective heat transfer coefficient, and thermal conductivity of the fluid. However, the effects of the wall friction factor of the canister, form loss coefficient of the grid spacers, and thermal conductivities of the solid materials, on the PCT were predominantly ignored.
        4,300원
        17.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: The potential impact of aqueous extracts from Psidium guajava leaves on the reproductive system of female rabbits was evaluated. Methods: Twenty-eight rabbits, aged five to six months were utilized. Rabbits were divided into four groups and were randomly assigned to receive one of the following oral doses of the guava leaf extracts: 0 (control group), 10, 20, or 30 mg/kg of body weight. After a treatment period of 30 days, blood was collected via jugular venipunture and the serum was extracted for the assessment of serum biochemical traits levels. The females were bred and monitored throughout their pregnancy to ascertain reproductive outcomes. Results: The results indicated that the guava leaf extract significantly increased the body weight of the rabbits during both pre- and post-pregnancy compared to the control group (p < 0.05). The litter size at three weeks post-birth, prolificity rate, FSH, LH, and protein levels were notably higher (p < 0.05) at a dose of 20 mg/kg of body weight. The viability rate three weeks post-birth increased with escalating extract doses, and the highest values were observed at doses of 20 and 30 mg/kg of body weight (p < 0.05). Conclusions: This study demonstrated that, the aqueous extract of guava leaves appears to stimulate the production of FSH, LH and enhance body weight, prolificity, and pregnancy outcomes in mammals. As such, it is suggested that a dose of 20 mg/kg body weight could be beneficial in improving the reproductive performance of female.
        4,000원
        20.
        2023.05 구독 인증기관·개인회원 무료
        The effects of an individual effective dose from radioactive contamination that will remain during site reuse after the decommissioning of nuclear facilities is generally assessed using the RESRAD code. The calculated results should meet the site reuse criteria presented by regulators, 0.25 mSv/yr in the United States and 0.1 mSv/yr in Korea. After completion of decommissioning, the dose is not subject to measurement, resulting in Derived Concentration Guideline Level (DCGL) remaining at the site that is practically consistent with the dose criteria. In order to assess dose using the RESRAD code, various requirements will need to be considered and determined, where the selection of input parameters is one of the important factors in the dose assessment. In addition, appropriate selection of site-specific parameters is important to reflect the site characteristics of each decommissioned Nuclear Power Plant (NPP). Therefore, this study intends to analyze the impact of site-specific parameters by referring to the cases of overseas decommissioned NPPs. In order to evaluate doses using RESRAD code, a site reuse scenario must first be selected. In general, in the case of unrestricted reuse, the resident farmer scenario can be applied, so the resident farmer scenario was also selected in this study. In addition, once a resident farmer scenario is selected, input parameters are selected according to the scenario, and the input parameter inputs a single value or distribution according to the deterministic or probabilistic evaluation method. Therefore, since this study is to evaluate the effect on site-specific parameters, a single value was applied as a deterministic evaluation method. For the 10 site-specific parameters considered in overseas cases, the difference was set twice using the F9 function key in the RESRAD code and the results were analyzed. In this study, we used prior research data targeting domestic nuclear facility for sensitivity analysis. Related parameters include the category of contamination layer, soil, water transport, ingestion, and occupancy. The parameters that appeared as the greatest influence among the 10 parameters were different in radionuclide on the contaminated zone. We showed the changes according to the difference in input parameters was presented using the graph provided by the RESRAD code. As a result, in the evaluation for Co-60 in this study, no significant change was observed. However, in case of H-3, several parameters values were changed, indicating that the effect on dose will be different depending on the site characteristics of the nuclear facilities.
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