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        검색결과 635

        21.
        2023.05 구독 인증기관·개인회원 무료
        The engineered barrier system (EBS) for deep geological disposal of high-level radioactive waste requires a buffer material that can prevent groundwater infiltration, protect the canister, dissipate decay heat effectively, and delay the transport of radioactive materials. To meet those stringent performance criteria, the buffer material is prepared as a compacted block with high-density using various press methods. However, crack and degradation induced by stress relaxation and moisture changes in the compacted bentonite blocks, which are manufactured according to the geometry of the disposal hole, can critically affect the performance of the buffer. Therefore, it is imperative to develop an adequate method for quality assessment of the compacted buffer block. Recently, several non-destructive testing methods, including elastic wave measurement technology, have been attempted to evaluate the quality and aging of various construction materials. In this study, we have evaluated the compressive wave velocity of compacted bentonite blocks via the ultrasonic velocity method (UVM) and free-free resonant column method (FFRC), and analyzed the relationship among compressive wave velocity, dry density, thermal conductivity, and strength parameter. We prepared compacted bentonite block specimens using the cold isostatic pressure (CIP) method under different water content and CIP pressure conditions. Based on multiple regression analysis, we suggest a prediction model for dry density in terms of manufacturing conditions. Additionally, we propose an empirical model to predict thermal conductivity and unconfined compressive strength based on compressive wave velocity. The database and suggested models in this study can contribute to the development of quality assessment and prediction techniques for compacted buffer blocks used in the construction of a disposal repository.
        22.
        2023.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        On January 4, 2020, the official Twitter account of the former US President Trump threatens to target Iran’s cultural heritage sites conditioned on any Iranian retaliation on US military forces then stationed in the Middle East. The immediate context was that the US-led drone strike had killed Iran’s Major General Qasem Soleimani in Iraq (Baghdad) only two days prior. This study critically analyzes whether “Tweets” uploaded to President Trump’s Twitter account could reasonably be construed as a type of harm against international law instruments and framework on the safeguarding of cultural heritage. This paper provides a brief contextual overview of President Trump’s Tweets; traces the historical destruction of cultural property during conflicts and discusses the preservation of heritage; delineates international laws and assesses whether President Trump and the US might be legally bound to refrain from threats to destroy cultural property; and examines the increasing role of social media in the evolution of the idea of diplomacy.
        5,800원
        24.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Among the Additive Manufacturing (AM) technologies, the Binder-Jetting printing technology is a method of spraying an adhesive on the surface of powder and laminate layer by layer. Recently, this technique has become a major issue in the production of large casting products such as ship-building, custom vehicles and so on. In this study, we performed research to make actual mold castings and increase mechanical property by using special sand and water-based binders. For use as a mold, it has a strength of more than 3MPa and permeability. Various experiments were carried out to obtain suitable them. The major process parameters were binder jetting volume, binder types, layer thickness and heat treatment condition. As a result of this study, the binder drop quantity was measured to be about 60 pico-liter, layer thickness was 100μm and the heat treatment condition was measured about 1,000℃ and compressive strength were measured to be more than 5MPa. The optimum condition of this experiment was established through actual casting of aluminum. The equipment used in this study was a Freeforms T400 model (SFS Co., Ltd.), and the printing area of 420 * 300 * 250mm and resolution of 600dpi can be realized.
        4,000원
        25.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study collected powder extinguishers with 6-10 years of elapsed life from January 2012 to January 2017 in market, factory, and apartment areas to experiment with changes in fineness and to examine the characteristics of extinguishing power. First, in the case of ABC powder, 98.3 wt% of the 8-year market area and 98.6 wt% of the 10-year apartment complex were found to be inappropriate in the first, second, and third arithmetic average analysis of the powder extinguisher from 6 to 10 years. That is, the fine distribution and size of the powder extinguishing agent particles should be managed within an appropriate range. It is analyzed that the powder fire extinguisher may experience a change in the fineness of the powder depending on the external environment exposure, placement, management status, and age of use, resulting in a decrease in digestive power or inability to radiate. Second, the fire extinguisher cannot be used in the initial fire suppression depending on the place of deployment, the environment of deployment, the progress of the number of years of use, and maintenance, so it is necessary to strengthen the device that enables fire extinguisher maintenance and inspection. Third, in the manufacturing process, the charging method should also be reviewed in consideration of the conditions of the workplace, the humid season, and the rainy environment.
        4,000원
        26.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The differentiation of Chinese characters is accompanied by the development of Chinese writing and is one of the manifestations of the adaptation of Chinese characters to record Chinese language. There are not only macroscopic and microscopic reasons, but also textual factors and linguistic factors for the differentiation of Chinese characters. To record Chinese accurately and clearly is the radical cause of character differentiation. The emergence of specific differentiated characters has its own influencing factors. It is particularly important to investigate the lexical items and their properties recorded by the mother characters to uncover the specific causes of the differentiation. In terms of lexical items, the degree of meaning clarity, semantic alienation and that of prominence and emphasis are the important factors that affect whether the lexical items represented by the mother character can obtain graphic marks independently, which is helpful to explore the internal motivation of Chinese character differentiation.
        5,700원
        27.
        2022.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper summarizes and assesses the international trend, both in doctrine and in legal provisions dealing with conflict of laws in intellectual property field and reviews the relevant provisions in the Part 5th on applicable law to civil relations evolving foreign elements of the Vietnam’s 2015 Civil Code. The author shows that the two new provisions of the Vietnam’s 2015 Civil Code, namely Article 679 and Article 683, has partly caught up with the international trend in recognizing conflicts of laws and providing choice-of-law rules for resolving these conflicts in the intellectual property relations. The shortcoming of the Vietnam’s 2015 Civil Code is the absence of a particular provision dealing with the conflict of laws in case of infringement of intellectual property rights. On that basis, the paper offers comments and suggestions on the need to make the provisions of the Vietnam’s Civil Code more specific in the future.
        4,900원
        29.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To solve the problem of water pollution, researchers have proposed a photocatalytic degradation technology, in which the key factor is the development of efficient photocatalytic materials. Graphitic carbon nitride (g-C3N4), an n-type semiconductor, has been widely studied due to its suitable band gap (2.7 eV), low cost, easy preparation, non-toxicity, and high photostability. However, the pure-phase g-C3N4 still has defects such as low specific surface area, insufficient visible light absorption, low charge mobility, few active sites for interfacial reaction, and easy recombination of photogenerated electron–hole pairs, which leads to the lower photocatalytic activity of g-C3N4. Aiming at the problems mentioned above, this paper focus on the synthesis of g-C3N4-based composites with high photocatalytic activity via lemon juice induction method. Thiourea and lemon juice were selected as precursors, and carbon quantum dots (CQDs) as electron mediators were introduced anchoring on the surface of g-C3N4 to build g-C3N4/CQDs with compact interface. The results showed that small-sized CQDs are uniformly distributed on the surface of g-C3N4, and the g-C3N4/CQDs composite has a 2D0D structure, which reduces the recombination of photogenerated electron–hole pairs. The photocatalytic degradation efficiency of 4% g-C3N4/CQDs for RhB reaches the highest data of 90.9%, and the photocatalytic degradation rate is 0.016 min− 1, which is about 2.3 times that of g-C3N4. After four cycles of photocatalytic reaction, the photocatalytic degradation efficiency of the material remained at 81.7%. Therefore, the g-C3N4/CQDs synthesized via lemon juice induction has a more stable microstructure, and the charge separation efficiency is greatly improved, which is suitable for practical photocatalytic environmental protection.
        4,300원
        30.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        AlSi10Mg alloys are being actively studied through additive manufacturing for application in the automobile and aerospace industries because of their excellent mechanical properties. To obtain a consistently high quality product through additive manufacturing, studying the flowability and spreadability of the metal powder is necessary. AlSi10Mg powder easily forms an oxide film on the powder surface and has hydrophilic properties, making it vulnerable to moisture. Therefore, in this study, AlSi10Mg powder was hydrophobically modified through silane surface treatment to improve the flowability and spreadability by reducing the effects of moisture. The improved flowability according to the number of silane surface treatments was confirmed using a Carney flowmeter. In addition, to confirm the effects of improved spreadability, the powder prior to surface treatment and that subjected to surface treatment four times were measured and compared using s self-designed recoating tester. The results of this study confirmed the improved flowability and spreadability based on the modified metal powder from hydrophilic to hydrophobic for obtaining a highquality additive manufacturing product.
        4,000원
        31.
        2022.10 구독 인증기관·개인회원 무료
        Cement is widely used as representative industrial material. In Korea, about 50 million tons of cement are consumed every year. In the manufacture of cement, raw materials containing NORM such as fly ash and bauxite are used. Therefore, the workers can be subjected to radiation exposure. The major exposure pathway in NORM industries is internal exposure due to inhalation of aerosol. Internal radiation dose due to aerosol inhalation varies depending on physicochemical properties of the aerosol. Therefore, the objective of this study was to investigate aerosol properties influencing inhalation dose in cement industries. In this study, aerosol properties were measured for two cement manufacturers. A particulate size distribution and concentration at various processing areas in cement manufacturing industries in Korea were analyzed using a cascade impactor. The mass density of raw materials and byproducts were measured using pycnometer. Shape of particulates was analyzed using SEM. The radioactivity concentration of Ra-226, Ra-228 for U/Th decay series was measured using HPGe. Particulate concentration by size was distributed log-normally with maximum at particle size about 7.2 μm in manufacturer A and 5.2 μm in manufacturer B. The mass density of fly ash and cement were 2.3±0.06, 3.2±0.02 g/cm3 respectively in manufacturer A. In manufacturer B, the mass density of bauxite and cement were 3.4±0.02, 2.9±0.01 g/cm3 respectively. The shape of particulates appeared as spherical shape in manufacturer A and B regardless of sampling area. Thus, a shape factor of unity could be assumed. The radioactivity concentrations of Ra-226, Ra-228 were 82±9, 82±8 Bq/kg for fly ash, and 25±4, 23±3 Bq/kg for cement in manufacturer A. In manufacturer B, the radioactivity concentrations of Ra-226, Ra-228 were 344±34, 391±32 Bq/kg for bauxite, and 122±13, 145±12 Bq/kg for cement. The radioactivity concentrations of Ra-226, Ra-228 in cement were less than raw materials such as fly ash and bauxite. It is because the dilution of the radioactivity concentration occurred during mixing with other raw materials in cement production process. This study results will be used as database for accurate dose assessment due to airborne particulate inhalation by workers in cement industries.
        33.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        High-temperature friction performances of graphite blocks (GBs) and zinc phosphate impregnated graphite blocks (IGBs) were evaluated under various friction temperatures. The surface of IGB exhibited extremely lower average friction coefficient values, that was 0.007 at 400 °C and 0.008 at 450 °C, in comparison to that of GB (0.13 at 400 °C and 0.16 at 450 °C, respectively). The worn surface of IGB in the high-temperature friction test was smoother and more complete than that of GB. The wear under high temperature and load caused the transformation of zinc pyrophosphate to zinc metaphosphate and the formation of a continuous large-area boundary lubrication layer combined with graphite and metallic element on the wear surface. The superior tribology property of IGB could be attributed to the digestion of iron oxides by tribo-chemical reactions and passivation of the exposed dangling covalent bonds. Specifically, the layered structure generated on the IGB wear interface effectively decreased the adhesive forces and prevented the surface from serious damage.
        4,300원
        34.
        2022.07 구독 인증기관 무료, 개인회원 유료
        개인정보의 가치가 높아지면서 개인정보의 보 호에 관심이 높아지고 있다. 개인정보 보호 방법 을 논의하기 위해서는 먼저 개인정보가 법적으로 어떠한 성격을 갖고 있는지에 대하여 논의할 필 요가 있다. 개인정보에 대한 정보주체의 권리를 인격권으로 파악하는 관점은 개인이 자유로운 의 사에 의하여 개인정보를 제공할지 여부를 결정하 여 제공한 것이므로 이에 대한 법적 보호가 이루 어진다고 파악한다. 미국에서는 개인정보를 재산 권의 대상으로 보는 관점이 있는데 이는 개인이 개인정보 제공에 대한 결정을 내리고 개인정보를 제공받는 상대로부터 개인정보의 제공과 사용에 대한 보상을 받아 개인정보 사용에 대한 외부 효 과를 정보주체인 자신에게 이전한다는 것을 내용 으로 한다. 생각건대개인정보가개인에게 재산적 가치를 가질 수 있더라도 명시적 근거 없이 개인 정보의 법적 성격을 재산권으로 해석하기는 어렵 고, 인격권의대상으로 보아개인정보를 인격권적 측면에서 보호하는 것이 보다 타당하다고 할 것 이다. 정보주체는 개인정보처리자로부터 서비스를 제공받기 위해서 일정한 개인정보를 제공하게 된 다. 이렇게 제공된 개인정보가 유출되는 사고가 발생하였을 때 정보주체는 피해가 현실화되는 상 황을 기다리기보다는 유출 사고 발생에 초점을 맞추어피해의구제를꾀하게된다. 우리나라에서 개인정보 유출 사고에 대한 소송은 개인정보가 유출된 정보주체들이 공동으로 소송을 제기하여 개인정보처리자에게 정신적 손해에 대한 위자료 를 청구하는 특징이 있다. 이렇게 제기된 소송은 장기간에 걸쳐 진행되고 개인정보 유출 사고 발 생 자체를 정보주체에 대한 손해 발생으로 보아 정보주체 1인당10만원상당의배상금을 인정하 는 경우가 많다. 정보주체에 대한 보호를 강화하 기 위하여 개인정보보호법에 법정손해배상제도, 징벌적손해배상제도가 도입되었으나 이러한 제도 가 활용된 사례를 찾기 어렵다. 최근 발표된 민법 개정안은 인격권을 명문화하 면서 인격권의 예시로 개인정보를 들고 있다. 개 정안이 통과된다면 우리나라에서 개인정보의 법 적 성격은 입법적으로 인격권이 된다. 다만 인격 권으로서의 개인정보 보호를 위해 개정안에 포함된 침해예방청구권 등을 활용하고자 한다면 청구 의 상대방에 개인정보처리자가 포함되는지 여부 에 대한 추가적인 논의가 필요하다. 개인정보 유 출 사고 예방과 사고 발생 시 침해된 이익 회복을 위한 적당한 조치 등에 있어 개인정보처리자를 청구의 상대방으로 포함할 수 있을 것인지에 대 한 보완이 이루어질 때 개인정보 보호가 더 강화 될 수 있을 것이다.
        4,900원
        35.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Novel Ni- and Fe-based alloys are developed to impart improved mechanical properties and corrosion resistance. The designed alloys are manufactured as a powder and deposited on a steel substrate using a high-velocity oxygen-fuel process. The coating layer demonstrates good corrosion resistance, and the thus-formed passive film is beneficial because of the Cr contained in the alloy system. Furthermore, during low-temperature heat treatment, factors that deteriorate the properties and which may arise during high-temperature heat treatment, are avoided. For the heattreated coating layers, the hardness increases by up to 32% and the corrosion resistance improves. The influence of the heat treatment is investigated through various methods and is considered to enhance the mechanical properties and corrosion resistance of the coating layer.
        4,000원
        36.
        2022.05 구독 인증기관·개인회원 무료
        Garnet is one of the promising ceramic waste forms for immobilizing radioactive wastes. It has an A3 [VIII]B2 [VI]T3 [IV]O12 structure, so it can accommodate various cations of different sizes and coordination. Silicon usually occupies the centers of the tetrahedron structural site (T[IV]O4) in natural garnet. However, substitution of the T-site with iron, which has a relatively large ionic radius, causes the expansion of a unit cell volume of garnet and allows the incorporation of large cations such as actinides at other sites. Relatively few leaching data have been reported for ferrite garnet waste forms to date. In this study, we synthesized gadolinium-iron-garnet and evaluated the leaching property using cerium as a surrogate for actinide elements. The test specimens were made by cold pressing and sintering process. Three different standard leaching tests were performed as follows. The PCT-A (ASTM C1285) was performed for 7 days at 90°C to the crushed sample (0.149 to 0.074 mm). The ANSI/ANS-16.1 standard leach test was performed at ambient conditions for 5 days with constant replacement of leachate. Finally, the MCC-1 (ASTM C1220) test was performed for 28 days at 90°C with different types of leachants such as ultrapure water, brine, and silicate water. The last two leaching tests were conducted on monolithic specimens. After the end of the test, leachate was analyzed by inductively coupled plasma mass spectroscopy (Agilent, ICP-MS 7700S).
        38.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We have prepared MIL-101/graphene oxide (GO) composites with various mixing molar ratio of Fe-containing metal– organic frameworks (MOFs) against GO. When synthesizing MOFs, it was possible to synthesize uniform crystal powders using hydrothermal method. MIL-101 consists of a terephthalic acid (TPA) ligand, with the central metal composed of Fe, which was the working electrode material for supercapacitors. Field emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy analysis had been done to ascertain microstructures and morphologies of the composites. Cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge–discharge measurements were performed to analyze the electrochemical properties of the composite electrodes in 6 M KOH electrolyte. By controlling the metal ligand mole ratio against GO, we prepared a changed MOF structure and a different composite morphology, which could be studied as one of the promising optimized electrode materials for supercapacitors.
        4,200원
        39.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigates the effect of process stopping and restarting on the microstructure and local nanoindentation properties of 316L stainless steel manufactured via selective laser melting (SLM). We find that stopping the SLM process midway, exposing the substrate to air having an oxygen concentration of 22% or more for 12 h, and subsequently restarting the process, makes little difference to the density of the restarted area (~ 99.8%) as compared to the previously melted area of the substrate below. While the microstructure and pore distribution near the stop/restart area changes, this modified process does not induce the development of unusual features, such as an inhomogeneous microstructure or irregular pore distribution in the substrate. An analysis of the stiffness and hardness values of the nano-indented steel also reveals very little change at the joint of the stop/restart area. Further, we discuss the possible and effective follow-up actions of stopping and subsequently restarting the SLM process.
        4,000원
        40.
        2022.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Transition metal carbides (TMCs) are used to process difficult-to-cut materials due to the trend of requiring superior wear and corrosion properties compared to those of cemented carbides used in the cutting industry. In this study, TMC (TiC, TaC, Mo2C, and NbC)-based cermets were consolidated by spark plasma sintering at 1,300 oC (60 oCmin) with a pressure of 60 MPa with Co addition. The sintering behavior of TMCs depended exponentially on the function of the sintering exponent. The Mo2C-6Co cermet was fully densified, with a relative density of 100.0 %. The Co-binder penetrated the hard phase (carbides) by dissolving and re-precipitating, which completely densified the material. The mechanical properties of the TMCs were determined according to their grain size and elastic modulus: TiC-6Co showed the highest hardness of 1,872.9 MPa, while NbC-6Co showed the highest fracture toughness of 10.6 MPa*m1/2. The strengthened grain boundaries due to high interfacial energy could cause a high elastic modules; therefore, TiC-6Co showed a value of 452 ± 12 GPa.
        4,000원
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