A bilateral Nuclear Cooperation Agreement (NCA) should define what is subject to the agreement and when. Nuclear Materials (NM) are the subject of NCA with almost all countries, and the definition used in these agreements is borrowed from Article 20 of the IAEA Charter. The IAEA’s definition of NM as consisting of special fissionable material and source material and describes the types of material each contains. In order to control the export of NM under national laws and implement NCA, not only the types of NM but also quantitative criteria are required. This is because controlling small quantities of NM is impossible, unnecessary, and would create excessive administrative burdens. For this reason, the NSG guidelines establish a quantitative threshold of NM requiring control. Nevertheless, no quantitative thresholds have been agreed upon for NM subject to a NCA. Whether NM transferred is subject to the NCA is primarily a matter for the supplier states to determine. The supplier states make the decision based on quantitative criteria defined in their own export control laws. ROK identifies NM that require export licenses by reflecting the same criteria as the NSG guidelines in Foreign Trade Laws and its Notifications. Less than 500 kg of Natural Uranium, 1,000 kg of Depleted Uranium, 1,000 kg of Thorium, and 50 effective grams of special fissionable materials do not require an export license and is therefore not subject to NCA. In the US, the quantitative threshold for requiring an export license is different from that of ROK. For example, special fissionable materials that are not Pu are required if the individual shipment exceed 1 effective gram or 100 effective grams per year. The difference in the quantitative thresholds for NM between the two countries mean that the same item may be subject to NCA under US standards, but not under ROK’s. For example, the export of 8 grams of highly enriched uranium (93%) contained in a neutron detector would not be subject to the NCA in ROK, but would be considered NM subject to a NCA and required a special license in the US. Of course, in order to ensure the application of safeguards and physical protection to all NM transferred between the two countries, the agreement may not include a quantitative threshold for NM. However, the absence of such a threshold can lead to different conclusions by the two countries on the same item and make it challenging to control retransfers. The definition of quantitative standards will be necessary in the supplementary administrative arrangement for the practical control and management of NM subject to the NCA.

이 글은 남한 동해안에 유입된 북한 생활쓰레기로부터 시작된다. 그동안 북한 쓰레기가 남한에 유입된다는 사실은 해양쓰레기 실태조사 관련 연구 에서 주로 이루어졌다. 환동해권 해양쓰레기 유입 등에 관한 연구에서도 주로 한국과 일본, 극동러시아 등의 유입 현황에 관한 연구는 있지만, 북 한은 논의의 대상에서 제외되었다. 본 연구는 기존의 해양학 관점이 아닌 북한학 관점에서 남한 해안에 유입된 북한 쓰레기 문제를 다루었다. 북한 생활쓰레기 중 상품포장지는 직접적으로 북한 상품 생산 현황과 브랜드 등을 알 수 있으며, 간접적으로는 북한 내 경제 상황과 상품 유통 지역망 등을 알 수 있기 때문이다. 동해안 지역에서 수거한 북한제품 포장지를 살 펴보면 대부분 생산공장은 평양으로 표기되었다. 이를 통해 평양에서 생산 한 제품이 동해안 지역으로 유통됨을 알 수 있다. 또한 동해안 지역은 북 한을 대표하는 대도시인 원산, 청진, 함흥, 라선 등이 있는데, 실제로 상품 포장지에는 이 지역 생산공장이 표기되는 사례도 있었다. 김정은 집권 이 후 매년 국가적 차원에서 국가디자인전시회를 개최할 만큼 산업미술을 강 조하는데, 특히 상품의 고유한 특징을 표현하는 상표도안을 강조한다. 본 연구에서는 동해안 주요 도시에서 생산한 제품을 중심으로 같은 품목이지 만 공장별로 어떻게 상표도안이 다른지 살펴봤다. 북한 쓰레기에 대한 북 한학적 시각과 해양학적 시각의 학제간 연구를 통해 남한에 유입되는 북 한 생활쓰레기에 대한 연구의 폭을 넓혀갈 필요가 있다.

This paper reports the results of an experimental examination using X-rays to test annealing materials for lapped bearing steel (STB2), to confirm the validity of the weighted averaging analysis method. The distribution behavior for the sin diagram and the presence or absence of differences in the peak method, half-value breadth method, and centroid method were investigated. When lapping the annealed bearing steel (STB2) material, a residual stress state with a non-directional steep gradient appeared in the surface layer, and it was found that the weighted averaging analysis method was effective. If there is a steep stress gradient, the sin diagram is curved and the diffraction intensity distribution curve becomes asymmetric, resulting in a difference between the peak method, half-value breadth method, and centroid method. This phenomenon was evident when the stress gradient was more than 2~3 kg/mm2/μm. In this case, if the position of the diffraction line is determined using the centroid method and the weighted averaging analysis method is applied, the stress value on the surface and the stress gradient under the surface can be obtained more accurately. When the stress gradient becomes a problem, since the curvature of the sin diagram appears clearly in the region of sin > 0.5, it is necessary to increase the inclination angle  as much as possible. In the case of a lapping layer, a more accurate value can be obtained by considering  in the weighted averaging analysis method. In an isotropic biaxial residual stress state, the presence or absence of  can be determined as the presence or absence of strain for sin≈0.4.

The surge in food delivery systems during the coronavirus 2019 pandemic necessitated this study of heavy metal migration from food contact materials (FCMs). A total of 104 samples of FCMs, comprising 51 polypropylene (PP), 21 polyethylene (PE), and 32 polystyrene (PS) samples of six different types of FCMs (containers, covers, table utensils, cups, pouches, and wrappers) used for food delivery distributed in Korea, were collected and investigated for migration of three heavy metals (Pb, Cd, and As) using inductively coupled plasma–mass spectrometry (ICP-MS) to determine whether they complied with Korea’s Standards and Specifications for Utensils, Containers, and Packages. Acetic acid (4%, v/v) was used as the food simulant, and tests were performed at 100oC (in harsh conditions) for 30 min. Linearity of Pb, Cd, and As showed acceptable results with a coefficient of determination (R2) value of 0.9999. Limit of detection (LOD) and limit of quantification (LOQ) of Pb, Cd, and As were 0.001, 0.001, and 0.001 μg/L and 0.002, 0.003, and 0.003 μg/L, respectively. Accuracy and precision results complied with the criteria presented in the European Commission Joint Research Centre guidelines. The average concentration of Pb, Cd, and As migration detected in a total of 104 samples was 0.009–0.260 μg/L, which was very low compared with the migration specification set in the Standards and Specifications for Utensils, Containers, and Packages. The maximum level of Pb corresponded to 0.23% of the migration limit. There were no samples exceeding the limit. Thus, this study confirmed that the heavy metal contents of FCMs used for delivery food distributed in Korea were safely managed. The data from this study represent an invaluable source for science-based safety management of hazardous heavy metals migrating from FCMs used in the food delivery industry.

Metal material production process machinery is becoming larger due to the development of industry. Since there are many overseas manufacturers of large machines used in industrial fields, there are limitations in investigating the manufacturer's noise prediction method and measurement method. A noise map was prepared to obtain information necessary for noise reduction and to effectively manage noise companies. It was modeled with the drawings provided to prepare the noise map and the results of the actual measurement of the site. In order to improve the noise environment of workers, there was a noise reduction effect when a soundproof wall was installed between the noise source and the worker's workplace.

이 논문은 정적 재하상태에 있는 무피복 강합성보와 내화피복을 적용한 강합성보를 대상으로 화재 시 내부 온도 및 수직처짐에 대 한 내화피복의 영향을 평가한 결과를 제시한다. 열응력해석을 위한 화재하중으로는 American Society for Testing and Materials E119 의 표준화재곡선을 사용했으며, 강재거더 표면에 부착하는 내화재료의 방화효과를 구현하기 위해 외기에서 강합성보로 전달되는 열 의 전달계수를 감소시켰다. 실규모 무피복 강합성보에 대한 구조화재실험에서 내부 온도분포와 수직처짐을 측정하였고 실험 결과와 의 비교를 통해 비선형 구조화재해석 결과의 타당성을 검증하였다. 내화피복이 적용된 강합성보의 구조화재해석 결과로부터 강재거 더 표면에 내화재를 적용할 경우 동일 화재 조건에서 무피복 강합성보에 비해 내부 온도와 수직처짐이 감소함을 알 수 있었다. 또한 열 전달계수의 변화에 따른 열응력 응답으로부터 화재 시 강합성보의 온도 및 구조거동에 대한 내화피복의 영향을 제시하였다.

Exposure to ultraviolet (UV) light is often associated with skin damage, sometimes very serious, and in recent times has received particular attention as a health risk. As a result, the proper use of sunscreen has long been recommended to protect against skin damage. The continued increase in the use of sunscreen may be linked to increased information about the risk of melanoma and non-melanoma skin cancer caused by prolonged exposure to ultraviolet rays. Natural and harmless materials that block and prevent UV light have emerged as essential household items in the field of skin beauty. New materials need to be considered and evaluated in relation to ultraviolet rays and their harmful effects. This study aims to explain the effect of UV exposure on human skin, the classification of sunscreens, the application of zeolite, nano clay, and LDH in sunscreen formulations, as well as the regulation of this service in various countries around the world.

본 연구는 코팅 방법을 활용한 단결정 양극 소재 연구로서 Ni-rich계 다결정 양극 소재로 부터 단결정 양극 소재를 합 성하여 사이클 구동 시 양극 소재의 안정성을 향상시키고자 한다. 양극 소재에 LixCoO2와 LixSnO3 를 각각 코팅하여 이차입자 내부 혹은 외부에 코팅층이 형성된 양극 소재를 합성한 후 이를 소결하여 단결정 형성에 대한 영향을 비교 하였다. 입자 외부에 LixSnO3가 코팅되어 열처리 된 Ni0.8Co0.1Mn0.1O2(NCM811)의 경우 코팅 처리 없이 열처리된 양극 소재 보다 개선된 수명특성을 보였으나, 단결정화가 이뤄지지 않았다. 입자 내부에 LixCoO2 코팅층이 형성된 NCM811 을 열처리 한 결과 이차입자 내부에 형성된 Co 코팅층이 결정화되어 50회 사이클 후 기준 단결정 양극 소재의 방전용 량인 117.34 mAh·g-1 대비 129.11 mAh·g-1의 높은 방전용량을 나타내었고, 형상제어를 통해 이성적인 단결정화가 이뤄 졌다. 본 연구는 다결정체인 Ni-rich 양극소재의 단결정화에 대한 유요한 통찰력을 제공할 것으로 예상한다.

Following the social requirement to strengthen field supervision of the asbestos containing materials (ACM) abatement process with regard to asbestos school buildings, this study was conducted to understand the status and characteristics of airborne asbestos that may potentially occur after the ACM abatement process is completed. In the area where a series of asbestos abatement processes were finally completed, comprehensive area air sampling was performed. For sample analysis, Transmission Electron Microscopy (TEM) was used according to The Asbestos Hazard Emergency Response Act (AHERA) method and Phase Contrast Microscopy (PCM) analysis was also performed. Airborne asbestos was detected in 29.5% of the total samples, and the average concentration was 0.0039 ± 0.0123 s/cc (12.3 ± 38.9 s/mm2). 4.5% of the total samples exceeded the AHERA standard (70.0 s/mm2) and the average concentration was 0.0528 ± 0.0256 s/cc (167.2 ± 82.0 s/mm2). Airborne asbestos was no longer detected at the point when AHERA is exceeded after re-cleaning. Most of the detected asbestos was chrysotile (94.4%) and the structure types of asbestos were Matrix (41.4%), Fiber (39.9%), Bundle (10.8%), and Cluster (7.8%). Among the asbestos structures detected through transmission electron microscope analysis, the asbestos structures satisfying PCM-equivalent structures were found to be 6% of the detected asbestos, indicating that there is a limitation of the PCM analysis to check the airborne asbestos in that area. As a result of reviewing the status of airborne asbestos that may potentially occur and the type and dimensions of asbestos structure detected in the area, since the airborne asbestos exposure caused by poor field supervision for the ACM abatement process could not be ruled out, thorough management is necessary. In addition, the result of this study could be used as scientific evidence for establishing and strengthening policies related to ACM abatement, including cases of school buildings.

We attempted to provide an overview of the laws and current state of the 3D printing industry in South Korea and around the world, using the annual industry surveys and the Wohler report. Additionally, we reviewed articles relating to the potential exposure to hazards associated with 3D printing using metal materials. In South Korea, there were 406 3D printing-related businesses, employing 2,365 workers, and the market size was estimated at 455.9 billion won in 2021. Globally, the average growth rate of the 3D printing industry market over the past 10 years was 27.4%, and the market size was estimated at $11.8 billion in 2019. The United States had the highest cumulative installation ratio of industrial 3D printers, followed by China, Japan, Germany, and South Korea. A total of 6,168 patents related to 3D printing were registered in the US between 2010 and 2019. Harmful factors during metal 3D printing was mainly evaluated in the powder bed fusion and direct energy deposition printing types, and there is a case of material extrusion type with metal additive filaments. The number, mass, size distribution, and chemical composition of particles were mainly evaluated. Particle concentration increases during the opening of the chamber or post-processing. However, operating the 3D printer in a ventilated chamber can reduce particle concentration to the background level. In order to have a safe and healthy environment for 3D printing, it is necessary to accumulate and apply knowledge through various studies.

This research studied the electrical characteristics, IR transmission characteristics, stealth functions, and thermal characteristics of infrared thermal-imaging cameras of copper-sputtered samples. Nylon samples were prepared for each density as a base material for copper-sputtering treatment. Copper-sputtered NFi, NM1, NM2, NM3, NM4, and NM5, showed electrical resistance of 0.8, 445.7, 80.7, 29.7, 0.3, and 2.2 Ω, respectively, all of which are very low values; for the mesh sample, the lower the density, the lower the electrical resistance. Measuring the IR transmittance showed that the infrared transmittance of the copper-sputtered samples was significantly reduced compared to the untreated sample. Compared to the untreated samples, the transmittance went from 92.0–64.1%. When copper sputtered surface was directed to the IR irradiator, the IR transmittance went from 73.5 to 43.8%. As the density of the sample increased, the transmittance tended to decreased. After the infrared thermal imaging, the absolute values of △R, △G, and △B of the copper phase increased from 2 to 167, 98 to 192, and 7 to 118, respectively, and the closer the density of the sample (NM5→NFi), the larger the absolute value. This proves that the dense copper phase-up sample has a stealth effect on the infrared thermal imaging camera. It is believed that the copper-sputtered nylon samples produced in this study have applications in multifunctional uniforms, bio-signal detection sensors, stage costumes, etc.