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        검색결과 255

        21.
        2023.05 구독 인증기관·개인회원 무료
        The types of waste generated in radiation controlled areas of nuclear facilities are very diverse. Among them, the waste containing hazardous materials such as electrical equipment and fire safety equipment that do not directly handle radioactive materials is also primarily classified as radioactive waste because it was used and stored in the radiation controlled area. Such wastes include periodic consumables such as fluorescent lamps, fire extinguishers, batteries, and gas containers after use. The waste is ambiguous and cannot be easily treated as radioactive waste or waste subject to clearance, and has been stored in a radiation controlled area for a long time, and the amount is continuously increasing. The storage space is saturated and has difficulty in management. IAEA ISO-7503-2016 clearly states that surface contamination measurement can be applied to surface contamination substrates (impermeable, non-activated) instead of volume contamination measurement. In order to solve these concerns, some facilities within the Korea Atomic Energy Research Institute were selected to explore self-disposal methods based on surface contamination in consideration of the characteristics of waste and facility contamination. The surface contamination degree and qualitative gamma spectroscopic analysis were carried out by the method. First, we examined the characteristics of the facility, the history of the air pollution level of the usage/storage space, and periodic inspection records. Second, we measured the physical properties (area/weight) of the waste in the same treatment way as the existing waste. Third, gamma dose rate and surface contamination (direct/indirect method) are measured for the entire area to confirm contamination is possible. It was confirmed that the concentration standard was satisfied. In order to clarify the presence of contamination, a qualitative method of gamma nuclide analysis was also performed. All surveys/measurements of 4 types of waste at 7 facilities were performed and it was confirmed that all waste satisfies the permissible concentration standard for clearance which conservatively set at 0.1 Bq/g as the permissible concentration standard. In the future, We hope that you will use this as a reference to search for easier disposal methods for regulatory bodies and specified waste disposal methods, and contribute to reducing the amount of radioactive waste generated.
        22.
        2023.05 구독 인증기관·개인회원 무료
        The rise of nuclear power plants to meet escalating global energy needs has made environmental pollution including the contamination of uranium due to improper disposal of radioactive wastewater during uranium milling and mining processes. Adsorption, a water purification method known for its fast kinetics, high selectivity, and ease of use, has emerged as a popular choice for the treatment of radioactive wastewater. In response to the critical need for the purification of radioactive wastewater contaminated with U(VI), this review provides a comprehensive summary of the various types of materials, synthetic methods, and adsorption mechanisms used for the purification process. The materials are categorized into four main groups: organic, inorganic, composite/nanomaterials, and framework materials. To enhance the adsorption capacity for U(VI), researchers have explored physical and chemical modifications as well as the development of organic-inorganic hybrids. The improved adsorption performance resulting from these modifications is mostly attributed to electrostatic interaction, surface complexation, and ion exchange mechanisms. However, despite the present understanding of the processes involved, further research is still needed to fully determine the optimal approach for purifying contaminated radioactive wastewater.
        23.
        2023.05 구독 인증기관·개인회원 무료
        90Sr is considered a hazardous radionuclide due to its long half-life of 28.8 years, radiotoxicity, and potential to bioaccumulate in various organisms. In the environment, strontium typically exists as divalent cation Sr2+ or in different complexes, depending on the environmental physical and chemical factors. Despite its mobility, Sr2+ transport remains affected by adsorption from solid phases, such as soil and sediments. This research aimed to investigate the efficiency of a magnetic flocculant (MNP/IF) in separating suspended soil and Sr2+ from a soil suspension. MNP/IF was prepared via the electrostatic interaction between magnetite particles and an inorganic flocculant (IF) composed of CaCO3 and Na2SO4. Analysis of the physical properties of MNP/IF confirmed that MNP/IF was successfully imparted with magnetism and had excellent adsorption capacity for Sr2+. The optimal MNP/IF dosage for the sedimentation of suspended soil was determined to be 0.3 g/g (mass ratio of flocculant to soil). The lower the pH, the more favorable the flocculation-sedimentation process of the suspended soil by MNP/IF, since Ca2+ and Mg2+, which are the most common strong flocculators, were further eluted from IF under acidic conditions. Besides, MNP/IF exhibited outstanding removal performance for Sr2+, with maximum adsorption capacities of 163.6 mg/g observed during the flocculation-sedimentation reaction of suspended soil. The adsorption of Sr2+ exhibited consistency with the Langmuir model and followed pseudo-second-order kinetics. These findings suggest that MNP/IF can be used for the simultaneous removal of suspended soil particles and Sr2+ from a radioactive soil suspension.
        24.
        2023.05 구독 인증기관·개인회원 무료
        Integrity evaluation scheme for Spent Fuel (SF) dry storage has been developed under transportation failure modes. This method especially considered the degradation characteristics of Spent Fuel (SF) during dry storage such as radial and circumferential hydride content, hydride volume fraction, oxide thickness, etc. Hydride and zircaloy cladding are considered as material composite system, using correlation models related to material properties. Critical Strain Energy Density (CSED) is compared with Strain Energy Density (SED), to evaluate cladding integrity. CSED serves as material characteristics, while SED can be considered as boundary condition. To calculate the CSED of cladding in the lateral failure mode, circumferential hydride concentration is used. SED is calculated considering both the bending moment and axial load. On the other hand, in the longitudinal failure case, fuel rod temperature, internal pressure, hoop stress, radial hydride concentration is used to calculate CSED. And pinch force (contact) was considered to evaluate SED. Model validations were conducted by comparing hot cell SF test and existing validated evaluation results. To separately handle normal transportation conditions from hypothetical accident conditions, SED according to stress-strain analysis results was separated into elastic and plastic regions. As a result of applying this scheme for 14×14 SF, failure probability of normal condition was zero, which is the similar result with DOE and same with EPRI. Regarding accident condition, lateral case showed similar result, but longitudinal case showed different but reasonable result, which was due to the different analysis conditions. The proposed methodology which was indigenously developed through this study is named as K-method.
        25.
        2023.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Stroke is one of the causes affecting gait and balance. Taping is considered an effective method for improving balance and gait in stroke patients. Numerous studies have confirmed the functional effects of taping in stroke patients. However, there is still no consensus regarding the use of taping to improve gait and balance. Objects: The purpose of this review was to investigate the effects of taping on the balance and gait of patients with stroke through meta-analysis of studies. Methods: PubMed, Medline, Embase, Web of Science, Cochrane Review, RISS, DBPia, and Science on were used to collect articles on Kinesio and non-elastic taping. The key terms were “Stroke”, “Hemiplegia”, “Taping”, “Tape”, “Balance”, and “Gait” with cut-off of October, 2022. Taping group was compared with control groups with sham, placebo, and no taping. The outcome measures included the Berg Balance Scale (BBS), Timed Up and Go (TUG) test, and gait speed (cm/s). Eighteen studies (524 patients) were selected for the meta-analysis. Results: Overall, taping improved balance and gait in stroke patients, and Kinesio and nonelastic taping had similar effect sizes. Taping improved the BBS and TUG, and was most effective on gait speed. Contrary to the expectation that a longer duration of taping would be more affective, taping was most effective when the total taping duration was shorter than 500 minutes. In addition, the effect size of taping was greater when it was simultaneously attached to multiple locations. Conclusion: This meta-analysis supports the use of taping to improve gait and balance in stroke patients, and provides guidelines for the location, duration, and type of tape to increase taping efficiency.
        4,000원
        29.
        2022.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Pilates exercises are used for body shape correction because they can achieve correct posture alignment through spinal stabilization. Objects: This study aimed to determine whether the use of reformers increases the effectiveness of Pilates core exercises on body alignment in standing. Methods: The study included 30 women without known diagnoses of musculoskeletal and neurological disorders or cancer. Those who had taken more than 10 Pilates lessons were excluded. The participants were randomly assigned to either the reformer exercise group or the mat exercise group, and interventional Pilates exercises were performed for 60 minutes a day, three times a week, for a total of 8 weeks. Ten movements of the reformer and mat Pilates core exercise programs were included. Exbody® 9100 MOMI musculoskeletal analysis equipment (Exbody Inc.) was used to assess the alignment of the standing posture in the frontal plane. Results: As a result of comparing the differences within and between the groups before and after the intervention using the two-way mixed analysis of variance test, height differences in the head, pelvis, left and right, shoulders, scapulas, knees, and ankles in the frontal plane after the intervention were found in both groups. For example, the left-right symmetry of the body alignment in the standing posture was significantly improved within each group (p < 0.05). However, no significant difference was found between the groups (p > 0.05). Conclusion: Both the reformer and mat Pilates core exercises were effective for standing posture alignment, which has clinical significance. If an exercise program is developed based on the analysis of movements necessary for posture improvement and the target muscles to be strengthened, the same effect can be achieved only with mat exercise without using the reformer equipment at the beginner stage.
        4,000원
        30.
        2022.10 구독 인증기관·개인회원 무료
        This study evaluated the synthesis of optimal materials for high efficiency adsorption and removal characteristics of Cs-137 for radioactive contaminated water, and considered thermal treatment methods to stabilize the spent adsorbent generated after treatment. We synthesized a composite adsorbent with a combination of impregnating metal ferrocyanide that improves the selectivity of Cs adsorption with zeolite capable of removing Cs as a support. The Cs removal efficiency of the composite adsorbent was evaluated, and the stability change of Cs according to the high-temperature sintering was evaluated as a stabilization method of the spent adsorbent. The metal ferrocyanide content of the adsorbent was in the range of 11.8~36.0%. The adsorption experiments were performed using a simulated liquid waste to have a total Cs concentration of 1 mg/L while containing a trace amount of Cs-137, and then gamma radioactivity was analyzed. In order to evaluate the stabilization of the spent adsorbent, heat treatment was performed in the range of 500~1,100°C, and the volatilization rate of Cs during heat treatment and the leaching rate of Cs after heat treatment were compared. In the adsorption experiment, the Cs removal efficiency was higher than 99%, regardless of the amount of metal ferrocyanide in the composite adsorbent. In the sintering experiment on the spent adsorbent, it was confirmed that there was no volatilization of Cs up to 850°C, and then the volatilization rate increased as the heating temperature increased. On the other hand, the leaching rate of Cs in the sintered adsorbent tends to significantly decrease as the heating temperature increases, so that Cs can be stabilized in the sintered body. In addition, as the content of metal ferrocyanide increases, the volatilization rate of Cs rapidly increases, indicating that the unstable metal ferrocyanide in the adsorbent may adversely affect the removal of Cs as well as the thermal treatment stability.
        31.
        2022.10 구독 인증기관·개인회원 무료
        A sequential column experiment was conducted for uranium removal of excessively high or highly U-contaminated soils, simultaneously. Two pilot-scale acryl columns with a 24 cm ID and 48 cm length were uniformly packed with each U-contaminated soil (both < 2 mm, 119, and 22.4 Bq/g as initial U-238 activities). A column packed with soil contained very high U constant located first then sequentially located second columns with relatively lower U-contaminated soil. Thus the effluents which passed very high U-contaminated soil and having extremely high dissolved U concentration was directly inflowed the second columns. Both columns initially and respectively flushed with demi water (or condensing water of air conditioner generated from radiation controlled area) to saturate and displace the air from the pore space. Elution was carried out with alkaline and acidic solutions, respectively, and sequentially. The uranium removal efficiencies were found and a comparison was made with the pilot soil flushing experiments. During this study, a new approach to reducing acidic flushing waste which is considered the biggest defect of soil washing/flushing was established, and optimal factors were calculated to demonstrate industrial-scale uranium decontamination of soil with high uranium content.
        32.
        2022.10 구독 인증기관·개인회원 무료
        This study aimed to remove uranium (U(VI)) ions from sulfate-based acidic soil-washing effluent using the ion-exchange method. For effective ion exchange of U(VI) ions under acidic conditions, one chelate resin (Purolite S950) stable under low pH conditions and two anion-exchange resins (Ambersep 400 SO4 and 920U SO4) used in sulfuric acid leaching systems were selected. The exchange performance of the three selected ion-exchange resins for U(VI) ions was evaluated under various experimental conditions, including ion-exchange resin dosages, pH conditions, reaction times, and reaction temperatures. U(VI) ion exchange was consistent with the Langmuir model and followed pseudo-second-order kinetics. Thermodynamic experiments revealed that the U(VI) ion exchange by the ion-exchange resins is an endothermic and spontaneous process. On the other hand, U(VI) ions was effectively desorbed from the ion-exchange resins using 0.5 M H2SO4 or Na2CO3 solution. Overall, on the basis of the results of the present study, we propose that Purolite S950, Ambersep 400 SO4, and Ambersep 920U SO4 are ion-exchange resins that can be practically applied to effectively remove U(VI) ions from sulfate-based acidic soil-washing effluents.
        35.
        2022.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The buffer is a critical barrier component in an engineered barrier system, and its purpose is to prevent potential radionuclides from leaking out from a damaged canister by filling the void in the repository. No experimental parameters exist that can describe the buffer expansion phenomenon when Kyeongju bentonite, which is a buffer candidate material available in Korea, is exposed to groundwater. As conventional experiments to determine these parameters are time consuming and complicated, simple swelling pressure tests, numerical modeling, and machine learning are used in this study to obtain the parameters required to establish a numerical model that can simulate swelling. Swelling tests conducted using Kyeongju bentonite are emulated using the COMSOL Multiphysics numerical analysis tool. Relationships between the swelling phenomenon and mechanical parameters are determined via an artificial neural network. Subsequently, by inputting the swelling tests results into the network, the values for the mechanical parameters of Kyeongju bentonite are obtained. Sensitivity analysis is performed to identify the influential parameters. Results of the numerical analysis based on the identified mechanical parameters are consistent with the experimental values.
        4,000원
        36.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        One of the promising supercapacitors for next-generation energy storage is zinc-ion hybrid supercapacitors. For the anode materials of the hybrid supercapacitors, three-dimensional (3D) graphene frameworks are promising electrode materials for electrochemical capacitors due to their intrinsic interconnectivity, excellent electrical conductivity, and high specific surface area. However, the traditional route by which 3D graphene frameworks are synthesized is energy- and time-intensive and difficult to apply on a large scale due to environmental risks. Here, we describe a simple, economical, and scalable method of fabricating grafoil (GF) directly into a graphite–graphene architecture. Both synthesizing of a porous structure and functionalization with interconnected graphene sheets can be simultaneously achieved using electrochemically modified graphite. The resultant graphite electrode provides a high capacitance of 140 mF/cm2 at 1 mA/cm2, 3.5 times higher than that of pristine grafoil, keeping 60.1% of its capacitance when the current density increases from 1 to 10 mA/cm2. Thus, the method to produce 3D graphene-based electrodes introduced in the current study is promising for the applications of energy storage devices.
        4,000원
        37.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        세계 4대 실명질환 중 하나인 연령관련 황반변성(Age-related Macular Degeneration, ARMD)에 관한 실험 모델 논문을 검토하면서, ARMD 예방과 치료를 위해 앞으로 나아가야 할 방향을 제시하고자 한다. ARMD 관련 한 전반적인 논문을 세포실험(in vitro)과 동물실험(in vivo)으로 나누어서 점검하고, 현재 진행하고 있는 연구와 한계점에 대해서 살펴보았다. ARMD 발병기전을 연구하고 이를 치료하기 위한 다양한 연구가 진행중이지만, 현재 까지 ARMD를 치료할 수 있는 명확한 치료제는 존재하지 않는다. ARMD 발병기전에 대한 지속적인 연구가 필요 하고, ARMD 치료와 예방을 위해 활용할 수 있는 천연물 후보물질 발굴이 필요하다고 사료된다.
        4,000원
        38.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적 : 본 연구에서는 다양한 우세안 검사 방법 중 3가지인 +2.00 D 검사, 원형구멍카드 검사, 접안렌즈 접근 검사에 따른 우세안을 알아보며, 우세안과 다른 요인인 우세손, 양안의 교정굴절력에 따른 일치성을 알아보고자 하였다. 방법 : 전신질환, 안질환, 굴절교정 수술 경험이 없는 평균연령 23.79±5.03세 성인 58명(남 36명, 여 22명) 을 대상으로 하였다. 완전 교정 상태를 만든 후 +2.00 D 렌즈 검사, 원형 구멍 카드법(hole in the card test), 접안렌즈 접근 검사를 시행하여 측정하였다. 결과 : 감각 우세안 우안 38명 좌안 20명, 시야 우세안 우안 45명 좌안 13명, 접안렌즈 우세안 우안 46명 좌 안 12명으로 우안의 비율이 높았다. 우세손은 오른손 56명 왼손 2명, 우세손과 우세안의 일치는 감각 우세안 38명, 시야 우세안 45명, 접안렌즈 우세안 44명으로 우세안과 우세손의 일치는 통계적으로 유의한 차이가 없었다 (p>0.050). 교정굴절력에 따른 우세안에서는 등가구면 굴절력에서 낮은 눈이 우세안인 경우 감각 우세안 18명 시 야 우세안 14명 접안렌즈 우세안 16명, 구면 굴절력에서 낮은 눈이 우세안인 경우 감각 우세안 24명 시야 우세안 19명 접안렌즈 우세안 19명, 원주 굴절력에서 낮은 눈이 우세안인 경우 감각 우세안 17명, 시야 우세안 21명 접 안렌즈 우세안 20명으로 교정굴절력이 낮은 눈과 우세안의 일치는 통계적으로 유의한 차이가 없었다(p>0.050). 결론 : 감각 우세안의 방향과 시야 우세안 방향의 일치는 유의한 차이를 보였다. 우세안은 측정법에 따라 다르게 판정될 수 있으므로 우세안 검사는 감각 우세안 검사와 시야 우세안 검사 두 가지 모두 해야 할 것으로 사료된다.
        4,000원
        39.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Sperm cryopreservation is a fundamental process for the long-term conservation of livestock genetic resources. Yet, the packaging method has been shown, among other factors, to affect the frozen-thawed (FT) sperm quality. This study aimed to develop a new mini-straw for sperm cryopreservation. In addition, the kinematic patterns, viability, acrosome integrity, and mitochondrial membrane potential (MMP) of boar spermatozoa frozen in the developed 0.25 mL straw, 0.25 mL (minitube, Germany), or 0.5 mL (IMV technologies, France) straws were assessed. Postthaw kinematic parameters were not different (experiment 1: total motility (33.89%, 32.42%), progressive motility (19.13%, 19.09%), curvilinear velocity (42.32, 42.86), and average path velocity (33.40, 33.62) for minitube and the developed straws, respectively. Further, the viability (38.56%, 34.03%), acrosome integrity (53.38%, 48.88%), MMP (42.32%, 36.71%) of spermatozoa frozen using both straw were not differ statistically (p > 0.05). In experiment two, the quality parameters for semen frozen in the developed straw were compared with the 0.5 mL IMV straw. The total motility (41.26%, 39.1%), progressive motility (24.62%, 23.25%), curvilinear velocity (46.44, 48.25), and average path velocity (37.98, 39.12), respectively, for IMV and the developed straw, did not differ statistically. Additionally, there was no significant difference in the viability (39.60%, 33.17%), acrosome integrity (46.23%, 43.23%), and MMP (39.66, 32.51) for IMV and the developed straw, respectively. These results validate the safety and efficiency of the developed straw and highlight its great potential for clinical application. Moreover, both 0.25 mL and 0.5 mL straws fit the present protocol for cryopreservation of boar spermatozoa.
        4,000원
        40.
        2022.06 구독 인증기관 무료, 개인회원 유료
        3,000원
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