검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 255

        1.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Sleep accounts for approximately one-third of a person’s lifetime. It is a relaxing activity that relieves mental and physical fatigue. Pillows of different sizes, shapes, and materials have been designed to improve sleep quality by achieving an optimal sleep posture. Objects: This study aimed to determine which pillow provides the most comfortable and supports the head and neck during sleep, which may enhance sleep quality. Methods: Twenty-eight healthy adults (19 males and 9 females) with an average age of 29 years participated in this cross-sectional study. This experiment was conducted while the participants laid down for 5 minutes in four different pillow conditions: (1) no pillow (NP), (2) neck support foam pillow (NSFP), (3) standard microfiber filled pillow (SFP), and (4) hybrid foam pillow (HFP). The head-neck peak pressure, cranio-vertebral angle in supine (CVAs), cranio-horizontal angle in supine (CHAs), chin-sternum distance (CSD), and muscle tone of sternocleidomastoid were analyzed using one-way repeated measures analysis of variance (ANOVA). The significance level was set at p < 0.05. Results: The head-neck peak pressure was the highest in the NSFP condition, followed by the NP, SFP, and HFP conditions. The CVAs, CHAs, and CSD of the SFP were lower than those of the other pillows. Muscle tone was the highest in the NP condition, followed by the of NSFP, HFP, and SFP conditions. The participants subjective comfort level in both the supine and side-lying postures was highest in the HFP condition, followed by the SFP and NSFP conditions. Conclusion: This study can be used to establish the importance of pillow selection for highquality sleep. The results of this study, suggest that a hybrid pillow with a good supportive core and appropriate fluffiness can maintain comfort and correct cervical spine alignment during sleep.
        4,000원
        2.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문의 목적은 한국이 직면한 뉴테러리즘 양상과 위협 요인을 분석해보고, 선제적으로 대응할 수 있는 과제에 대해 제시해 봄에 있다. 현재 한국은 포괄적 안보상황 하에서 대중과 다중이용시설 대상 무차별적 공격의 사전 차단 및 대량살상 등 전방위적으로 테러위협에 대응하고 있다. 이에 이 논문에서는 테러 수단의 첨단화 및 고도화되고 있는 뉴테러리즘에 대해 선제적으로 국가 및 국민적 인식을 강화하고 취약점 보완을 위해 법률적, 제도적 대응 방안을 제시했다. 또 포괄적 안보 상황을 반영하여 국내 테러 양상을 분석하고, 테러예방시스템 구축을 위한 통합방위법 및 테러방지법의 상호 연계성과 사법집행 강화를 위한 근거를 마련해야 한다. 특히 AI 기반의 테러예방 및 대응 시스템 등 4차 산업혁명의 신기술 적용을 토대로 테러위협을 선제적 으로 차단하고 이 같은 기술을 활용하는 대테러업무 담당자를 대상 으로 교육훈련을 강화할 수 있는 방안 역시 마련해야 한다.
        7,000원
        3.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Abstract Purpose : The purpose of this study is to compare corneal curvature, corneal topography, and non-surgical in refraction correction surgery to determine the difference in corneal curvature and shape between the two groups. Methods : The subjects of this study were 30 persons (60 eyes) who underwent refractive surgery and 30 non-surgery persons (60 eyes) who had no systemic or eye disease over the age of 20. The research method measured refractive error and corneal curvature in two groups using an autorefractor-keratometer, measured curvature by area of the cornea using corneal topography, and compared refractive surgery eyes and non-surgery eyes. Results : In area-specific corneal curvature, the plan for refractive surgery was 8.48±1.05 mm in area A (0~1.5 mm), 8.49±1.58 mm in area B (1.5~4.5 mm), 8.19±1.87 mm in area C (4.5~7.5 mm), and 7.93±2.87 mm in area D (7.5~10.0 mm). In non-surgery procedures, the corneal curvature by area was 7.65±0.82 mm in area A, 7.77±1.56 mm in area B, 7.70±2.27 mm in area C, and 7.88±3.42 mm in area D. Conclusion : A side effect of refractive surgery, it is believed that it can be used as data to understand the shape of the cornea while using an Autorefractor-keratometer and a corneal topography as prior tests. Key words : Corneal topography, Keratometer, Refractive surgery
        4,000원
        4.
        2023.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Changes in the microstructure and mechanical properties of as-roll-bonded AA6061/AA5052/AA1050 threelayered sheet with increasing annealing temperature were investigated in detail. The commercial AA6061, AA5052 and AA1050 sheets with 2 mm thickness were roll-bonded by multi-pass rolling at ambient temperature. The roll-bonded Al sheets were then annealed for 1 h at various temperatures from 200 to 400 °C. The specimens annealed up to 250 °C showed a typical deformation structure where the grains are elongated in the rolling direction in all regions. However, after annealing at 300 °C, while AA6061 and AA1050 regions still retained the deformation structure, but AA5052 region changed into complete recrystallization. For all the annealed materials, the fraction of high angle grain boundaries was lower than that of low angle grain boundaries. In addition, while the rolling texture of the {110}<112> and {123}<634> components strongly developed in the AA6061 and AA1050 regions, in the AA5052 region the recrystallization texture of the {100}<001> component developed. After annealing at 350 °C the recrystallization texture developed in all regions. The as-rolled material exhibited a relatively high tensile strength of 282 MPa and elongation of 18 %. However, the tensile strength decreased and the elongation increased gradually with the increase in annealing temperature. The changes in mechanical properties with increasing annealing temperature were compared with those of other three-layered Al sheets fabricated in previous studies.
        4,000원
        5.
        2023.11 구독 인증기관·개인회원 무료
        Various types of radioactive liquid and solid wastes are generated during the operation and decommissioning of nuclear power plants. To remove radionuclides Co-60, Cs-137 etc. from a liquid waste, the ion-exchange process based on organic resins has been commonly used for the operation of nuclear facilities. Due to the considerations for the final disposal of process endproduct, other treatment methods such as adsorption, precipitation using some inorganic materials have been suggested to prepare for large amounts of waste during decommissioning. This study evaluated sintering characteristics for radioactive precipitates generated during the liquid waste treatment process. The volume reduction efficiency and compressive strength of sintered pellets were the major parameters for the evaluation. Major components of a simulated precipitate were some coagulated (oxy) hydroxides containing light elements, such as Si, Al, Mg, Ca, and zeolite particles. Green pellets compressed to around 100 MPa were heated at a range of 750~850°C to synthesize sintered pellets. It was observed that the volume reduction percentages were higher than 50% in the appropriate sintering conditions. The volume reduction was caused by the reduction of void space between particles, which is an evidence of partial glassification and ceramization of the precipitates. This result can also be attributed to conversion reactions of zeolite particles into other minerals. The compressive strength ranged from 6 to 19 MPa. These results also showed a significant correlation with the volume reduction of sintered body. Although our lab-scale experiments showed many benefits of sintering for the precipitates, optimized conditions are needed for large-scale practical applications. Evaluation of sintering characteristics as a function of pellet size and further testing will be conducted in the future.
        6.
        2023.11 구독 인증기관·개인회원 무료
        Various dry active wastes (DAWs) have been accumulated in nuclear power plants since the DAWs are mostly combustible. KAERI has developed a thermochemical treatment process for the used decontamination paper as an operational waste to substitute for incineration process and to decontaminate radionuclides from the DAWs. The thermochemical process is composed of thermal decomposition in a closed vessel, chlorination of carbonated DAWs, separation of soluble chlorides captured in water by hydroxide precipitation, and immobilization of the precipitate. This study examined the third and fourth steps in the process to immobilize Co-60 by fabricating a stable wasteform. Precipitation behaviors were investigated in the chloride solution by adding 10 M KOH. It was shown that the precipitates were composed of Mg(OH)2 and Al(OH)3. Then, the glass-ceramic wasteform for the precipitates were produced by adding additive mixtures in which silica and boron oxide were blended with various ratios. The wasteform was evaluated in terms of volume reduction ratio, bulk density, compressive strength, and leachability.
        7.
        2023.11 구독 인증기관·개인회원 무료
        With the importance of permanent disposal of high-level radioactive waste (HLW) generated in Korea, the deep geological disposal system based on the KBS-3 type is being developed. Since the deep geological repository must provide the long-term isolation of HLW from the surface environment and normal habitats for humans, plants, and animals, it is essential to assess the longterm performance of the disposal facility considering thermal-hydraulic-mechanical-chemical (TH- M-C) evolution. Decay heat dissipated from HLW contained in the canister causes an increase in temperature in the adjacent area. The requirement for the maximum temperature is established in consideration of the possibility of bentonite degradation. Therefore, when designing the repository, the temperature in the region of interest should be identified in detail through the thermal evolution assessment to ensure that the design requirement is satisfied. In the thermal evolution analysis, it is needed to evaluate the temperature distribution over the entire area of the disposal panel to consider the heat generated from both a single canister and adjacent canisters. Computational fluid dynamics (CFD) codes are widely used for detailed temperature analysis but are limited to simulating a wide range. Accordingly, in this study, we developed an analytical solution-based program for efficiently calculating the temperature distribution throughout the deposition panel, which is based on threedimensional heat conduction equations. The code developed can assess the temperature distribution of engineered and natural barrier systems. Principal parameters to be inputted are as follows: (a) geometry of the panel (e.g. width, length, height, spacing between canisters), (b) geometry of the canister (e.g. diameter, height), (c) thermal properties of bentonite and host-rock, (d) initial conditions (e.g. residual heat, temperature), and (e) time information (e.g. canister emplacement rate, time-interval, period). Through the calculation for the conceptual problem of a deposition panel capable of accommodating 900 (i.e. 30×30) canisters, it was confirmed that the program can adequately predict when and where the maximum temperature will occur. It is expected that the overall temperature distribution within the panel can be obtained by the evaluation of the entire region using this program reflecting the detailed design of the repository to be developed in the future. In addition, the thermal evolution analysis considering the influence of other canisters can be performed by applying the results as boundary conditions in the CFD analysis.
        8.
        2023.10 구독 인증기관·개인회원 무료
        꽃노랑총채벌레(Frankliniella occidentalis)는 고추를 가해하는 주요 병해충 가운데 하나이다. 유충과 성충이 긁어빠는 구기로 잎과 열매에 가해하는 직접피해는 물론이고 일명 칼라병이라 일컬어지는 토마토반점위조바 이러스를 전파하는 간접피해를 주고 있다. 다양한 바이러스 내병성 품종이 농가에서 재배되고 있으나, 칼라병의 발병은 해를 거듭하며 증가하고 있다. 놀라운 사실은 일부 내병성 품종에 대해서 총채벌레의 유인력이 감수성 품종에 비해 높다는 사실이다. 본 연구는 꽃노랑총채벌레에 대한 고추의 항객성 기작을 분석하였다. 총채벌레에 이미 피해를 받은 고추는 다른 총채벌레의 접근을 억제하는 것은 물론이고 천적인 미끌애꽃노린재를 유인하였 다. 이 고추 내부에는 자스모닉산 생합성 관여 유전자의 발현이 증가하였다. 고추가 생산하는 향기성분을 SPME 방식으로 모아 분석한 결과 Green leaf volatile과 terpene류의 증가를 보였다. 시판되는 10개의 고추 품종을 대상으 로 항객성 생물 검정과 향기성분 분석을 실시한 결과 이상의 항객성 기작을 뒷받침하였다. 또한 근권세균 가운데 일부는 고추로 하여금 이러한 항객성을 유도하였다.
        11.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: A breast cancer is the second leading cause of cancer death in women worldwide and among different types of breast cancers, triple-negative breast cancer (TNBC) has a poor prognosis. Methods: We investigated the potential of ginsenoside compound K (CK), an active ingredient in the bio-transformed ginsenoside, to be used as a therapeutic ingredient by examining the effects of CK on cell proliferation, apoptosis, and cancer-related gene expressions in breast cancer cells. Results: From the results of treating MCF-7, an ER and PR-positive breast cancer cells, and MDA-MB-231 (TNBC) with CK at a concentration of 0-100 μM, the half maximal inhibitory concentration (IC50) values for each cell were 52.17 μM and 29.88 μM, respectively. And also, it was confirmed that cell migration was inhibited above the IC50 concentration. In addition, fluorescence analysis of Apoptosis/Necrosis showed that CK induced apoptosis rather than necrosis of breast cancer cells. Through qPCR, it was confirmed that the expression of genes related to apoptosis and cell cycle arrest was increased in CK-treated breast cancer cells, and it acted more effectively on TNBC. However, the expression of genes related to tumor invasion and metastasis is also increased, so it is necessary to consider the timing of application of CK as a potential therapeutic anticancer compound. Conclusions: CK showed a stronger inhibitory effect in TNBC with poor prognosis but considering the high tumor invasion and metastasis-related gene expression, the timing of application of CK should be considered.
        4,000원
        12.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: This study has mainly focused on finding pharmacological effects of ginsenosides that can reduce the unwanted side effects of the cytotoxic anticancer drugs and are highly effective on prostate cancer, colorectal cancer, liver cancer, hormone-dependent breast cancer, triple-negative breast cancer, and brain cancer (neuroblastoma). Methods: Minor and rare ginsenosides (GS) of Rh2 which have a high absorption ability and excellent pharmacological actions were treated with the 6 different types of cancer cell lines and their anticancer activities were investigated by analyzing gene expressions associated with various cancers through qPCR and other relevant methods. Results: In cancer cells exposed to Rh2, cell viability and cell migration were reduced, and apoptosis was induced. Each cancer cell was divided into three groups according to the cell proliferation response by Rh2; 1) A group in which the cell viability decreases inversely to an increase in Rh2 treatment concentration; 2) A group in which the cell viability rapidly decreases in Rh2 treatment above a certain level of concentration; 3) A group in which the cell viability was not suppressed below 20-30% even with 100 μL of Rh2, the highest concentration used in this study. Conclusions: It was shown that Rh2 has a significant effect on inhibiting the proliferation of prostate cancer cells and hormone-dependent breast cancer cells.
        4,300원
        13.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Smartphone addiction has emerged as a significant social problem. Numerous studies have indicated the association between smartphone use and discomfort in the musculoskeletal system of the upper extremities. Objects: This cross-sectional survey aimed to compare the characteristics of musculoskeletal pain in the neck, trunk, and upper limbs between individuals with smartphone addiction and those without addiction. Methods: We collected a total of 326 healthy individuals’ data from China and Korea who had owned and used smartphones for more than 5 years between 20–50s through an online questionnaire consisting of 84 questions in four major sections. The first part contained basic information on the participant's personal characteristics and smartphones. The second part contained questions about smartphone use and posture. The third part was the smartphone addiction. The fourth part was to investigate musculoskeletal pain in various upper body parts. Results: Smartphone addiction has a weak negative correlation with age (r = –0.20, p < 0.01) and a weak positive correlation with the hours of smartphone use (r = 0.376, p < 0.01). Frequent musculoskeletal pain symptoms related to smartphone use were observed in the neck, shoulder, lower back, and wrists. The hours of smartphone use was slightly positively associated with the prevalence of musculoskeletal pain in the shoulder (r = 0.162, p < 0.05) and lower back (r = 0.125, p < 0.05). The prevalence of musculoskeletal pain in the neck (χ2 = 3.993, p < 0.05), shoulder (χ2 = 6.465, p < 0.05), and wrist (χ2 = 4.645, p < 0.05) was significantly higher among females than males. Conclusion: The results suggest that smartphone addiction should be recognized as a dual concern encompassing both physical health and psychosocial aspects. Furthermore, healthcare professionals, including physicians and physical therapists, should consider clients' smartphone usage patterns when assessing and treating with musculoskeletal pain.
        4,000원
        14.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Studies investigating the immediate effects of a single intervention to correct forward head posture are rare. Objects: This study aimed to compare the changes in treatment effects in patients with forward head posture and neck pain after manual and self-exercise therapy over a 1-hour period. Methods: Twenty-eight participants were randomly divided into manual and self-exercise therapy groups. Following the initial evaluation, manual or self-exercise therapy was applied to each group for 30 minutes each in the prone, supine, and sitting positions. The variables measured were the craniovertebral angle (CVA), stress level, pain level, and sternocleidomastoid (SCM) stiffness. After the intervention, re-evaluation was conducted immediately, 30 minutes later, and 1 hour later. Two-way analysis of variance (ANOVA) was used to compare the maintenance of treatment effects between the two groups. Results: Based on the two-way mixed ANOVA variance, there was no interaction between the groups and time for all variables, and no main effects were found between the groups. However, a significant effect of time was observed (p < 0.05). Post hoc tests using Bonferroni's correction revealed that in both groups, the CVA, pain, and stress showed significant improvements immediately after the intervention compared with before the intervention, and these treatment effects were maintained for up to 1 hour after the treatment (p < 0.0083) in the manual therapy group. However, the stress level was maintained until 30 minutes later (p < 0.0083) in the self-exercise group. There was no significant decrease in right SCM stiffness before and after the intervention; however, left SCM stiffness significantly decreased after the self-exercise intervention (p < 0.0083). Conclusion: Both manual and self-exercise therapy for 30 minutes were effective in reducing forward head posture related to the CVA, pain, and stress levels. These effects persisted for at least 30 minutes.
        4,000원
        15.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적 : 본 연구는 시선추적 분야에 사용되는 적외선 동공 검출 기법을 기반으로 동공 크기 변화와 동공 간 거리 변화 분석을 통해 양안시기능을 타각적으로 측정하는 방법에 관해서 연구하고자 한다. 방법 : 남녀 23명(평균연령 27.27±8.84세)을 대상으로 원거리(3 m) 및 근거리(0.4 m)에서 적외선 필터를 사 용하여 만든 차폐렌즈(이하 차폐렌즈)로 커버테스트를 실시하여 편위량을 측정하였다. 또한, 근거리에서 눈앞에 각각 ±1.00 D의 렌즈를 부가한 상태에서 커버테스트를 실시하여 AC/A 비 측정을 하였다. 적외선 카메라를 사용 하여 위의 과정들을 모두 촬영하였고, OpenCV(Open Source Computer Vision)를 사용하여 영상 프레임별 동 공 간 거리와 동공 면적을 계산하였다. 결과 : 원거리 및 근거리 커버테스트 측정값의 T-검정 결과 원거리 및 근거리 커버테스트 모두 통계적으로 유 의한 차이(p<0.050)가 없는 것으로 나타났고, Bland-Altman 일치도 평가에서도 대부분의 값이 두 측정법 사이 95% 신뢰구간 내에 존재하였다. 경사 AC/A 비는 -1.00 D를 가입했을 때 p=0.015, +1.00 D를 가입했을 때 p=0.823으로 –1.00 D 렌즈를 가입했을 때 유의미한 차이가 발생하였고, 계산 AC/A 비는 유의한 차이가 나타나 지 않았다. AC/A 비의 일치도 평가 역시 두 검사법 간 평균 차이가 0.9 △로 나타났고, 산점도 역시 평균 차이 선 에 균일하게 배열하여 비교적 높은 일치도를 보였다. 결론 : 본 연구에서는 시선추적 기술에 활용되는 적외선 동공 검출 기법을 기반으로 양안시기능의 타각적 검사 법을 개발하였다. 동공 크기 변화와 동공 간 거리 변화 양상 분석을 통한 타각적 양안시기능 검사 방법이 실제 임 상에 적용된다면, 자각적 검사 방법의 한계를 극복할 수 있을 것으로 생각된다.
        4,500원
        16.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적 : 온라인으로 판매되고 있는 ‘자가 도수조절안경(adjustable-focus eyeglasses)’을 광학적으로 분석하고 착용자에게 어떤 영향을 가하는지 알아보고자 한다. 방법 : ‘자가 도수조절안경’의 우측렌즈를 광학적으로 분석하기 위하여 투영식 렌즈미터 (HLM-1, Huvitz, Korea)를 사용하였다. ‘자가 도수조절안경’의 중첩된 렌즈를 단일렌즈(앞 렌즈, 뒷 렌즈)로 분해하여 각각의 특정 지점과 중첩된 렌즈의 특정 지점의 구면 굴절력, 비점수차, 프리즘 및 기저방향을 측정하였다. 안질환 및 전신질 환이 없고, 굴절 교정수술을 하지 않은 23.58±4.08세, 성인 40명(80안)을 대상으로 ‘자가 도수조절안경’착용 전 후의 원거리 시력검사, 근거리 시력검사, 입체시 검사를 시행하였다. 결과 : ‘자가 도수조절안경’의 단일렌즈는 앞 렌즈의 구면 굴절력이 외측 방향은(–), 내측 방향은(+), 뒷 렌즈의 구면 굴절력이 외측방향은(+), 내측방향은(–)로 도수가 점차 변하는 구조로 나타났다. ‘자가 도수조절안경’의 중첩 된 렌즈의 구면 굴절력, 비점수차, 프리즘 및 기저방향은 불규칙하게 나타났다. ‘자가 도수조절안경’착용 후 시력 및 입체시가 착용 전과 비교했을 때, 모두 저하되었다. 결론 : 온라인으로 판매되고 있는 ‘자가 도수조절안경’은 광학적으로 양호하지 않고 안경사의 처방이 되지 않은 안경이므로 착용자에게 여러 부정적인 영향을 가한다. 따라서 ‘자가 도수조절안경’을 사용하는 건 적합하지 않다.
        4,300원
        17.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Despite numerous advances in in-vitro embryo production (IVP), many documented factors have been shown to influence the development of mammalian preimplantation embryos and the success of IVP. In this sense, elevated levels of reactive oxygen species (ROS) correlate with poor outcomes in assisted reproductive technologies (ART) due to oxidative stress (OS), which results from an imbalance between ROS production and neutralization. Indeed, excessive production of ROS compromises the structural and functional integrity of gametes and embryos both in vivo and in vitro. In particular, OS damages proteins, lipids, and DNA and accelerates cell apoptosis. Several in-vivo and in-vitro studies report an improvement in qualityrelevant parameters after the use of various antioxidants. In this review, we focus on OS and the source of free radicals and their effects on oocytes, sperm, and the embryo during IVP. In addition, antioxidants and their important role in IVP, supplementation during oocyte in vitro maturation (IVM), in vitro culture (IVC), and semen extenders were discussed. Nevertheless, various methods for determining the level of ROS in germ cells have been briefly described. Still, it is crucial to develop standardized antioxidant supplement systems to improve overall IVP success. Further studies should explore the safety, efficacy, mechanism of action, and combination of different antioxidants to improve IVP outcomes.
        4,000원
        18.
        2023.05 구독 인증기관·개인회원 무료
        Radioactive waste can be classified according to the concentration level for radionuclides, and the disposal method is different through the level. Gamma analysis is inevitably performed to determine the concentration of radioactive waste, and when a large amount of radioactive waste is generated, such as decommissioning nuclear facilities, it takes a lot of time to analyze samples. The performance of a lot of analysis can cause human errors and workload. In general, gamma analysis is performed using by HPGe detector. Recently, for convenience of analysis, commercial automatic sample changers applicable to the HPGe detectors were developed. The automatic sample changers generate individual analysis reports for each sample. In this study, gamma analysis procedure was improved using the application of the automatic sample changer and the automated data parsing using by Python. The application of automatic sample changers and data parsing technique can solve the problems. The human errors were reduced to 0% compared to the previous method by improving the gamma analysis procedure, and working time were also dramatically reduced. This automation of analysis procedure will contribute to reducing the burden of analysis work and reducing human errors through various improvements.
        19.
        2023.05 구독 인증기관·개인회원 무료
        Heavy water (D2O) is a coolant as well as a moderator of pressurized heavy water reactors (PHWRs). During operation of PHWRs, deuterium (H-2, D) in heavy water is gradually converted to tritium (H-3, T), which is a radioactive nuclide with a half-life of 12.3 years, by capturing neutron. Various radioactive wastes contaminated by T are generated upon the PHWR operation. Owing to the similarity of D and T, they behave together a form of water (either liquid or vapor) in a normal circumstance. To handle D and T with the water form is quite difficult because it is not a solid and is highly mobile in nature. In this study, a mineralization technique to fix D and T in a solid form is suggested. It is considered that hydroxide minerals, which have low solubility in water, might tightly bind D and T in non-mobile, solid-state media. Feasibility of this strategy is studied by using a copper-based hydroxide mineral, atacamite. Atacamite is a natural mineral found in copper deposits with chemical formula of Cu2Cl(OH)3. Atacamite can be simply synthesized in laboratories by a precipitation method using copper chloride and calcium carbonate as precursors. Both chemicals were added into heavy water to obtain pale-green precipitates. Heavy water is the only source for D in this reaction and thus deuterated mineral is expected to be form. The obtained deuterated mineral, suspected to be Cu2Cl(OD)3, was then immersed in natural deionized water (extremely low D2O concentration) for several days to identify how fast D in Cu2Cl(OD)3 dissolves into water. In a preliminary Fourier transform infrared (FTIR) spectroscopy, absorption peaks related to HDO and D2O were not observed in the deionized water which is recovered after the immersion test, suggesting that D remained stable in the synthesized mineral. However, owing to low detection limit of FTIR, more precise analysis should be taken to clearly identify the stability of D of the deuterated atacamite. If deuterated hydroxide minerals are found to have sufficiently high D stability in natural water, they can be further treated with cement or other stabilization media to form a final wasteform for underground disposal.
        20.
        2023.05 구독 인증기관·개인회원 무료
        Various dry actives wastes (e.g., gloves, wipers, shoes, clothes) are generated during operation and maintenance of nuclear facilities. Among those, latex gloves gets interest because they contain both organic and inorganic compounds. CaCO3 is a common filler material for production of latex rubbers. Here, latex gloves were thermally treated in a closed vessel to separate the organic and inorganic compounds. Using the closed vessel is beneficial as it can prevent escape of any species, including radioactive nuclides in a real case, generated during the treatment. It was found that thermal decomposition of latex gloves occurred above 250°C. Latex gloves were decomposed to gas, liquid, and solid compounds. The gas product is thought to be volatile organic compounds (VOCs). The liquid product seems to be a mixture of oils and water. A CaCO3 phase was identified in the solid product, as expected. The VOCs can be easily separated at room temperature by purging in vacuum or inert atmosphere. The liquid-solid mixture can be separated by distillation. It is thought that gammaemitting nuclides, such as Cs-137, Sr-90, and Co-60, dominantly remain in the solid product. In the best situation, the solid product is the only subject to be transferred to final wasteform fabrication stream and thus volume of final waste can be reduced. Surrogates of contaminated latex gloves (containing Cs, Sr, and Co) were prepared and they were treated at 350°C in the closed vessel. How these contaminants behaves in this thermal process will be discussed in the presentation.
        1 2 3 4 5