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        검색결과 603

        101.
        2022.10 구독 인증기관·개인회원 무료
        In the present work, a three-phase AC arc plasma torch system is proposed to separate inorganic radioactive materials from the organic liquid waste. For this purpose, first, assuming the resistance of arc plasma ranges between 0.1 and 0.2 ohm, we designed a three-phase AC arc plasma power supply with the power level of 20 kW. Then, a three phase arc plasma torch consisting of three carbon rods with the diameter of 20 mm was designed and mounted on a cylindrical combustion chamber with the inner diameter of 150 mm. Detail design and basic performance of the plasma system were presented and discussed for application to the treatment of radioactive slurry wastes.
        102.
        2022.10 구독 인증기관·개인회원 무료
        In this work, we report the basic performance of a 100 kW class mobile plasma melting system consisting of two 24-ft commercial containers, each in charge of the plasma utilities and melting process. In this system, a 100 kW class transferred type plasma torch has been installed together with a crucible having an inner volume of 2,884 cm3. Filling the inner volume of the crucible with the simulated metal waste, such as bolts and nuts, melting tests have been carried out for 5 min by varying plasma input power from 50 kW to 100 kW. By measuring the volume of metal waste before and after melting test, then, the volume reduction rates were estimated and discussed.
        103.
        2022.10 구독 인증기관·개인회원 무료
        We developed a 100 kW Class Transferred Type Plasma Torch applicable for melting of noncombustible metal wastes. By employing reverse polarity discharge structures for hollow electrode plasma torch, a transferred type arc plasma was generated stably with long arc length higher than 10 cm at the arc currents of ~400 A and gas (N2) flow rate of ~50 lpm. High arc currents and high arc voltages caused by the increased arc length could input high power level of ~100 kW to the noncombustible metal wastes, enabling quick melting. In addition, relatively long arc length and low gas flow rates can help reduce the deposition of melted materials on the exit surface of the torch. Thanks to these features, the developed plasma torch is expected to be suitable for small-scaled and portable melting system.
        104.
        2022.10 구독 인증기관·개인회원 무료
        Se-79, a fission product of uranium, is present in spent nuclear fuel. Selenium is volatilized from the spent nuclear fuel during the pretreatment of pyroprocessing, and a filter composed of calcium oxide can capture gaseous selenium in the form of CaSeO3. Because Se-79 has a long half-life (3.27E5 years) and selenite ions have high mobility in groundwater, they must be immobilized in a chemically stable form for final disposal. This study used a composition of 50 TeO2 - 10 Al2O3 - 10 B2O3 - 10 Na2O - 10 CaO - 10 ZnO (mol%). High-purity powders of TeO2, Al2O3, H3BO3, Na2CO3, CaCO3, and ZnO were used as glass precursors. The mixed powders were placed in alumina crucibles and melted in an electric furnace under an ambient atmosphere at 800°C for 1 h before being cast on a carbon mold. The obtained glasses were ground into fine powders and then mixed with CaSeO3 powders. The powders were melted in alumina crucibles at 800°C for 1 h. To simulate a seleniumcaptured calcium filter, CaSeO3 was synthesized by a precipitation method using sodium selenite (Na2SeO3) and calcium nitrate (Ca(NO3)2) solutions. The glass samples were analyzed by an X-ray diffractometer (XRD). Retention of Se in tellurite glasses was analyzed by an X-ray fluorescence spectrometer (XRF) and inductively coupled plasma (ICP). The chemical durability of tellurite glass was evaluated through the PCT method.
        107.
        2022.10 구독 인증기관·개인회원 무료
        Radioactive cesium is a heat generated and semi-volitile nuclide in spent nuclear fuel (SNF). It is released gasous phase by head-end treatment which is a pretreatment of pyroprocessing. One of the capturing methods of gasous radioactive cesium is using zeolite. After ion-exchanged zeolite, it is transformed to ceramic waste form which is durable ceramic structure by heat treatment. Various ceramic wasteforms for Cs immobilization have been researched such as cesium aluminosilicate (CsAlSi2O6), cesium zirconium phosphate (CsZr2(PO4)3), cesium titanate (CsxAlxTi8-xO16, Cs2TiNb6O18) and CsZr0.5W1.5O6. The cesium pollucite is composed to aluminosilicate framework and cesium ion incorporated in matrix materials lattices. Many researchers are reported that the pollucite have high chemical durability. In this study, the Cesium pollucite was fabricated using mixtures of aluminosilicate denoted Absorbent product (AP) and Cs2CO3 by calcination and pelletized by cold pressing. The characterization of fabricated pollucite powder and pellets was analyzed by XRD, TGA, SEM, SEMEDS and XRF. The chemical durability of pollucite powder was evaulated by PCT-A and ICP-MS and OES. Thus, the optimal pressure condition without breaking the pellets which is low Cs2O/AP ratio and pelletizing pressure was selected. The long-term leaching test was performed using MCC-1 method for 28 days with the fabricated pollucite pellets. The leachate of leaching test was allard groundwaster and Deionized water and replaced 5 contact periods which is 3 hours, 3 days, 7 days, 14 days and 28 days and analyzed by ICPMS. The leaching rate was shown two stages. The first stage was rapid and relatively large amount of nuclides were leached. The leaching rate was decreased in the second stage. The fractional release rate of this study was shown same trend. These results were similar to previous studies.
        111.
        2022.10 구독 인증기관·개인회원 무료
        Filtering nuclides in high-level nuclear waste using rotating plasmas is a physical separation method based on mass difference. Since it is not chemical separation or metallurgical separation, the elements are separated regardless of their chemical composition. Accordingly, the more the number of chemical elements present in the waste or the more difficult when using the differences in solubility, the more advantageous. However, to be economically competitive, new concepts for rotating plasmas are needed to improve the poor separation rates despite high energy and installation costs. In this work, we revisited a counter rotating plasma centrifuge to examine its potential as an effective device for separating nuclear waste efficiently and economically.
        112.
        2022.10 구독 인증기관·개인회원 무료
        To ensure the peaceful use of nuclear energy, nuclear safeguards are applied in member states of the International Atomic Energy Agency (IAEA) under the Non-Proliferation Treaty. The two major considerations in implementing nuclear safeguards are effectiveness and efficiency. In terms of efficiency, the IAEA has a great interest in using containment and surveillance (C/S) technology to maintain continuity of knowledge. A representative means of C/S technology is a sealing system to detect tampering. The existing sealing systems used by the IAEA are of limited functionality in realtime verification purposes. To address this limitation, the present study develops a real-time verification sealing system. First, we analyzed the design requirements of a sealing system proposed by various institutions including the IAEA, the U.S. Nuclear Regulatory Commission, and a number of national laboratories and companies. Then, we identified the appropriate design requirements of this system for real-time verification. Finally, the prototype system was developed and tested based on the identified design requirements. The validation tests of the prototype system were performed for anticipated environmental conditions, radiation resistance, and safeguards functionality. Additionally, we are developing user-friendly verification software. The software validation is planned to perform for functionality, performance efficiency, and security. The next step is to develop a commercialized realtime verification sealing system based on the results of validation tests. Using this commercialized system, we plan to evaluate the performance in various actual use cases. Such a system is expected to significantly enhance the efficiency of nuclear safeguards.
        116.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Indian gooseberry (Emblica officinalis), also known as aonla or amla, belongs to the Euphorbiaceae family and is native to India, Sri Lanka, Malaysia, Thailand, and China. This fruit is gaining popularity globally because of its medicinal as well as nutraceutical properties. It is one of India's most integral commercial crops and is recognized for its nutritive, nutraceutical, and therapeutic value. India ranks first in the world in terms of cultivation and production, and it is mostly cultivated in Uttar Pradesh, Maharashtra, Gujarat, Rajasthan, Andhra Pradesh, Karnataka, Tamil Nadu, and Himachal Pradesh. Over the past decade, the area covered by this fruit has increased to approximately 25,000 ha. The total area under production is approximately 93,000 ha, with an annual production of approximately 1,090 thousand metric tonnes of fruit. Although India has favorable climatic conditions for growing gooseberry, its cultivation and production remain challenging because of pests as well as diseases, which cause considerable damage. In this study, we discuss the current status of Indian gooseberry production, as well as the major insect pests in the gooseberry-growing regions of India.
        4,000원
        117.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        기후 변화의 가속화로 국내 제주 및 남부 지방을 중심으로 열대 및 아열대 작물의 재배 및 소비가 증가하는 추세이다.오크라는 식용적 가치가 있을 뿐만 아니라, 품종별 고유의 꼬 투리와 잎의 색은 관상적 가치가 있어 조경 식물로 많이 사용 되고 있다. 본 연구는 도심 내 옥상 온실에 관상식물인 오크 라를 도입하기 위해 피트모스와 펄라이트 비율에 따른 기초 종자 발아 및 육묘기 실험을 진행하였다. 피트모스와 펄라이 트 비율은 PT:PL=1:2, 1:1, 2:1, 4:1 네 가지로 조성하였다. 발 아율은 파종 후 7일차부터 다른 처리구에 비해 피트모스:펄라 이트=1:2의 처리구에서 가장 높았다. 파종 후 28일차와 70일 차에 줄기길이, 경경, 뿌리길이, 지상부와 지하부의 생체중과 건물중 그리고 엽면적은 피트모스:펄라이트=1:2 처리구에서 가장 높았다. 그러나, 파종 후 56일 이후부터 엽수는 피트모 스:펄라이트=1:2, 2:1, 4:1 처리구에서 감소하였다. 피트모스: 펄라이트=1:1, 2:1, 4:1 처리구에서 식물이 필요로 하는 피트 모스의 비율이 지나치게 높아 높은 피트모스 비율로 인하여 수분함수량이 과도하게 높아 식물이 고사한 것으로 판단된다. 따라서 오크라를 관상식물로 활용하기 위해서는 피트모스와 펄라이트를 1:2로 혼합한 배지가 가장 적합하다.
        4,000원
        118.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is first to understand whether technology innovation capability, which is considered an important factor in the Root companies, directly affects the business performance of the company. Second, it was attempted to determine whether internal resources deemed necessary for a company's continuous competitive advantage and excellent business performance play a mediating role in the technological innovation capability of the Root companies and the business performance. The implications of this study derived from the research results are as follows: Among the elements of technology innovation capability, R&D capability, positively affects both financial and non-financial performance. It was confirmed that the investment ratio could positively affect financial performance such as sales, market share, and yield, and non-financial performance such as corporate image, employee satisfaction, and productivity. Among the factors of technology innovation capability, the technology innovation system positively affects both financial and non-financial performance. Therefore, it can be said that securing rights to owned technology, establishing technology and funding, efficient use of resources, etc., affects financial performance such as sales or market share of a company, and affect the company's production capacity, image, and employee satisfaction. It has been verified that internal resources, including financial, physical, and human resources, can mediate between the three elements of technology innovation capability and corporate financial and non-financial performance.
        4,600원
        119.
        2022.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this work, we developed silver nanowires and a silicon based Schottky junction and demonstrated ultrafast broadband photosensing behavior. The current device had a response speed that was ultrafast, with a rising time of 36 μs and a falling time of 382 μs, and it had a high level of repeatability across a broad spectrum of wavelengths (λ = 365 to 940 nm). Furthermore, it exhibited excellent responsivity of 60 mA/W and a significant detectivity of 3.5 × 1012 Jones at a λ = 940 nm with an intensity of 0.2 mW cm2 under zero bias operating voltage, which reflects a boost of 50%, by using the AC PV effect. This excellent broadband performance was caused by the photon-induced alternative photocurrent effect, which changed the way the optoelectronics work. This innovative approach will open a second door to the potential design of a broadband ultrafast device for use in cutting-edge optoelectronics.
        4,000원
        120.
        2022.05 구독 인증기관·개인회원 무료
        Sulfate-rich waste powder containing a radioactive nuclide is generated from chemical decontamination process and radioactive liquid waste treatment using ion exchange resin. The radioactive sulfate-rich waste powder should be stabilized for final disposal. The techniques for immobilization of the radioactive sulfate-rich waste powder such as hydraulic cement, geopolymer, and iron phosphate glass have been applied, however, there are limitation in these techniques. Firstly, the hydraulic cement cannot applied to the wastes containing high concentration of sulfate because the expansion, cracks, and disintegration can be happened in the waste form. Geopolymer has a low density although they can be used as a good binder. The iron phosphate glass can be utilized, however, a considerable amount of SO2 gas is emitted due to the high sintering temperature. In this study, immobilization of radioactive sulfate-rich waste powder was carried out to resolve above problems by applying low temperature sintering method using a low-melting glass. As a result, it was confirmed that the waste form has a high bulk density. The compressive strength of the waste form was over 40 MPa, which is higher than the acceptance criteria (≥ 3.44 MPa). From ANS 16.1 test, it was verified that the waste form met the acceptance criteria of the leachability index (≥ 6). It was also confirmed that the waste form was chemically durable through product consistency test (PCT). In addition, the chemical stabilities of waste forms were compared following the sintering condition and the composition of the waste forms. The difference of the chemical stability was explained by difference in the abundance of chemical form obtained from the sequential extraction test.