본 연구는 금속 인공물을 감소시키기 위한 VAT(view angle tilting)와 SEMAC(slice encoding for metal correction) 기법 적용에 따른 온도 변화 범위를 관찰하고자 하였다. 제작된 인체 모방 팬텀을 활용하였고, 검사방법으로는 임상에서 실제로 사용하고 있는 고속스핀에코(fast spin echo, FSE) 기법의 영상 파라미터들을 그대로 이용하였다. VAT 와 SEMAC 기법은 FSE와 같은 파라미터로 설정한 다음 VAT 파라미터는 100%와 SEMAC 파라미터는 25로 설정하였다. 온도 측정 방법으로는 수소원자 공명주파수전이법(proton resonance frequency shift, PRFS)기법을 활용하였으며, 광 섬유 온도계(fiber-optic sensor, FOS)로 절대 온도를 측정한 후 비교 분석하였다. 온도 변화는 SEMAC 기법에서 기존 FSE 기법 (0.28℃±0.10℃)에 비해 1.63℃±0.12℃로 약 6배 상승하였고(SEMAC-FOS = 1.59℃), VAT 기법은 약 2배 증가(VAT-FOS = 0.51℃)가 확인되었다. 특히, SEMAC 기법은 VAT 기법(VAT-FOS = 0.51℃, VAT-PRFS = 0.54℃ ±0.02℃)과 비교하여 약 3배가 증가하여 가장 높은 온도 상승이 관찰되었다. 이는 SEMAC 기법 적용 시 자기공명영상 전자파 인체 영양에 대한 안전기준을 충족하기 위해 영상 파라미터 최적화 작업의 필요성을 시사한다.

The standards for heavy metal levels in crustaceans are 0.5 mg/kg and 1.0 mg/kg or lower for lead and cadmium, respectively. Further, the contamination levels of arsenic, mercury, methyl mercury, and tin are being continuously investigated, considering their current exposure levels. Shrimps are potentially exposed to heavy metals because they inhabit areas with abundant organic matter, such as sandy or muddy shores, places with a lot of seaweed, and estuaries. This study measured the monetary value of reducing consumer anxiety and increasing consumer confidence if the government prohibits the sale of shrimp species that exceed the threshold for specific heavy metals and of the top shrimp species for which no threshold for heavy metals is specified. We derived consumer willingness-topay (WTP). Combining the estimated WTP with the number of households in the country, the total value of benefits was estimated to be 363.9 billion won. The results of this study will provide an important empirical finding, showing to what extent specific policies regarding heavy metals in seafood can alleviate consumer anxiety and provide psychological reassurance.

담도 스텐트가 인접한 담도 주위 혈관에 손상을 주어 혈액 담즙증을 유발하거나 스텐트 제거 시 손상으로 발생할 수 있다고 드물게 보고된다. 스텐트 제거 시 활력징후가 불안정 해질 정도의 혈액 담즙증이 생기는 경우, 혈관조영술을 시행 하기 전 구조 요법으로 피막형 팽창성 금속 스텐트의 압박 효과를 통한 지혈을 기대하고 삽입할 수 있다. 본 두 증례는 간문부 담관암 환자에서 간문부 폐색에 대해 삽입한 담도 스텐트 그리고 간세포암종 환자에서 간동맥 화학색전술 이후 동반된 간농양의 내배액 목적으로 삽입한 담도 스텐트를 각각 교체 목적으로 제거 후 급격히 악화된 대량의 혈액 담즙증을 피막형 팽창성 금속 스텐트를 삽입하여 성공적으로 치료된 사례이다. 한편, 해당 상황에선 정확한 출혈 위치를 알기 어려워 예상되는 출혈 위치를 포함할 수 있을 만큼 높은 위치에 스텐트를 삽입해야 하며 적절한 위치에 삽입되었더라도 지혈이 되지 않을 수 있기에 일시적인 방안이며 스텐트 자체의 한계점들도 있다. 따라서, 기존의 스텐트 제거 시 혈액 담즙증이 발생할 수 있음을 인지하고, 그중 출혈의 위험성이 높은 환자에서는 제거 전 영상 검사를 고려해야 하며 출혈이 발생한 뒤 스텐트를 통해 성공적으로 지혈을 시행했더라도 출혈 및 가성동맥류와 같은 혈관 기형의 확인을 위한 영상 검사를 고려해야한다.

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.

The semiconductor industry faces physical limitations due to its top-down manufacturing processes. High cost of EUV equipment, time loss during tens or hundreds of photolithography steps, overlay, etch process errors, and contamination issues owing to photolithography still exist and may become more serious with the miniaturization of semiconductor devices. Therefore, a bottom-up approach is required to overcome these issues. The key technology that enables bottom-up semiconductor manufacturing is area-selective atomic layer deposition (ASALD). Here, various ASALD processes for elemental metals, such as Co, Cu, Ir, Ni, Pt, and Ru, are reviewed. Surface treatments using chemical species, such as self-assembled monolayers and small-molecule inhibitors, to control the hydrophilicity of the surface have been introduced. Finally, we discuss the future applications of metal ASALD processes.

To raise the physical strength of alginate beads, this study manufactured alginate-cellulose bead by adding cellulose to alginate, and wanted to identify whether falginate-cellulose beads were sufficiently efficient in removing heavy metals. To find out optimal amounts of alginate and cellulose injection, this study conducted a pilot study, and repeated experiments proved that alginate 2 w/v% + cellulose 1 w/v% were the optimal amounts in manufacturing beads. Using micro materials tester, this study compared strengths of alginate beads and alginate-cellulose beads. Choosing Cd2+, Pb2+, and Ni2+ as materials to be removed, this study analyzed concentrations of them before and after the treatment. Experiments showed that, compared with alginate beads, the strength of alginate-cellulose beads was 2.26 times stronger, and that the latter could remove 98.22%, 99.99%, and 92.57% of Cd2+, Pb2+, Ni2+, respectively. While addition of cellulose to alginate made the absorption rate drop by about 1%, the beads were still highly efficient in removing heavy metals. Accordingly, it seems that alginate-cellulose beads can be used in removing heavy metals.

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 study was conducted to determine the concentration of heavy metals and their characteristics in the bodies of 2,446 residents living near industrial areas from 2007 to 2015. The concentration of heavy metals showed diverse characteristics according to gender, food types consumed and period of residence. Especially, levels of cadmium and mercury were high in the urine samples of the group that had lived in the local area for a long time. In order to obtain more accurate results, it will be necessary to comprehensively study the influence and effects from such matters related to lifestyle, eating habits and levels of environmental pollutants.

In this study, crystallization was effectively suppressed in Al-based metallic glasses (Al-MGs) during pulverization by cryo-milling by applying an extremely low processing temperature and using a surfactant. Before Al-MGs can be used as an additive in Ag paste for solar cells, the particle sizes of the Al-MGs must be reduced by milling. However, during the ball milling process crystallization of the Al-MG is a problem. Once the Al-MG is crystallized, they no longer exhibit glass-like behavior, such as thermoplastic deformation, which is critical to decrease the electrical resistance of the Ag electrode. The main reason for crystallization during the ball milling process is the heat generated by collisions between the particles and the balls, or between the particles. Once the heat reaches the crystallization temperature of the Al-MGs, they start crystallization. Another reason for the crystallization is agglomeration of the particles. If the initially fed particles become severely agglomerated, they coalesce instead of being pulverized during the milling. The coalesced particles experience more collisions and finally crystallize. In this study, the heat generated during milling was suppressed by using cryo-milling with liquid-nitrogen, which was regularly fed into the milling jar. Also, the MG powders were dispersed using a surfactant before milling, so that the problem of agglomeration was resolved. Cryo-milling with the surfactant led to D50 = 10 um after 6 h milling, and we finally achieved a specific contact resistance of 0.22 mΩcm2 and electrical resistivity of 2.81 μΩcm using the milled MG particles.

This research measured the change in mechanical characteristics of a sample obtained by finishing a metal coating to an engineering plastic manufactured using a 3D printer to satisfy both lightweight and quality characteristics. High-Temp material, which can be applied to space thermal environments with large temperature fluctuations, was applied as the engineering plastic material, and Stereolithography(SLA) method, which has relatively higher precision than Fused Film Fabrication(FFF) method, was selected as the manufacturing method. Electroless & electroplating were performed by metal coating on the surface to satisfy the characteristics of products requiring electrical conductivity. Tensile and bending tests were conducted to verify a change in the mechanical characteristics of a sample completed with a metal coating, and an adhesion test of the metal coating was also added.

The most comprehensive and particularly reliable method for non-destructively measuring the residual stress of the surface layer of metals is the sin method. When X-rays were used the relationship of sin measured on the surface layer of the processing metal did not show linearity when the sin method was used. In this case, since the effective penetration depth changes according to the changing direction of the incident X-ray,  becomes a sin function. Since  cannot be used as a constant, the relationship in sin cannot be linear. Therefore, in this paper, the orthogonal function method according to Warren’s diffraction theory and the basic profile of normal distribution were synthesized, and the X-ray diffraction profile was calculated and reviewed when there was a linear strain (stress) gradient on the surface. When there is a strain gradient, the X-ray diffraction profile becomes asymmetric, and as a result, the peak position, the position of half-maximum, and the centroid position show different values. The difference between the peak position and the centroid position appeared more clearly as the strain (stress) gradient became larger, and the basic profile width was smaller. The weighted average strain enables stress analysis when there is a strain (stress) gradient, based on the strain value corresponding to the centroid position of the diffracted X-rays. At the 1/5 max height of X-ray diffraction, the position where the diffracted X-ray is divided into two by drawing a straight line parallel to the background, corresponds approximately to the centroid position.

이 글은 중국에서 북송(960~1127)과 남송(1127~1279) 시기에 유행하였던 점다법(點 茶法)에 사용되었던 금속제 다구를 통해 송대의 차문화의 역사적 의미와 고려 차문화를 살 펴본다. 차의 정수는 차 거품이라는 의견은 당대의 육우에 의해 주장된 바 있다. 이 차의 거품을 맛있고 멋있게 만들기 위해 점다문화가 투다문화로 발전한 것은 차의 정치사를 행했던 송대 사회의 문화적 특징으로 이해된다. 일반 백성에서 황제에 까지 공유되었던 점다문화는 차의 질과 다구의 질을 계층에 따라 달랐고 사치가 극성하게 된 배경이 되었다. 칠기, 주석, 흑자와 청자 그리고 백자의 도자기, 주석, 금은기 등의 다양한 재질로 다도구가 제작되었고 특히 금은기는 감상수준으로 발전하 는 원동력이 되었다. 금은제 다도구는 송대 이전의 황실의 다도구인 법문사 지궁의 의종의 공양품을 통해 살펴 보았다. 바로 이 법문사의 다구를 통해 차의 포말을 즐기는 점다법으로 이해되는 다문화의 과정을 엿볼 수 있었다. 송대의 점다법에 구사된 금속제 다기에 대해서는 그간 연구된 바가 없었다. 이글에서는 금은기로 만든 주자와 잔과 탁의 기형을 종합적으로 이해하는 방식으로 고찰해 보았다. 13 세기 팽주 교장의 금은기를 통해 두립형의 잔과 끼우게 되어 있는 구조의 탁, 그리고 절견형 의 주자는 다기로 사용하였을 가능성을 제시하였다. 송대 점다법을 수용한 고려의 금속제 다구들의 존재를 은숟가락과 미국 보스턴박물관 소 장의 금도은제주자와 승반을 통해 살펴보았다. 이 다구들에서 동시대의 국제적 흐름을 타면 서도 고려만의 독자적인 미감이 파악되었다.

리튬 금속 기반 전극의 높은 용량에도 불구하고, 제어가 어려운 덴드라이트 성장은 낮은 쿨롱 효율, 안전 문제를 야기해, 리튬금속 배터리의 상용화를 제한한다. 본 연구에서는 압전 복합체인 BaTiO3/PVDF (BTO@PVDF) 기반 보호층을 리튬금속에 코팅, 덴드라이트에 의한 부피팽창으로 발생한 변형을 분극을 이용하여, 리튬 금속 전극의 안정성 및 성능을 향상 하고자 한다. 이를 통해, 균일한 리튬이온의 증착이 가능해졌으며, BTO@PVDF 전극은 100 사이클 동안 약 98.1% 이상의 쿨 롱 효율을 나타내었다. 또한, CV를 통해 향상된 리튬이온의 확산계수(DLi+) 증가를 보였으며, 본 연구에서 제시된 전략은 리 튬 금속 전극의 성능 향상에 새로운 길을 나타내준다.

There is a considerable amount of research on metal material product worker’s hearing loss caused by noise that comes from manufacturing process. A further investigation that characterizes the sound that comes from manufacturing process of metal material products. however. To do this, a noise management plan is needed. It should include a generated sound process from the main sources of disturbance at manufacturing process areas. And a soundproof measurement will identify the amount of noise reduction needed for a hearing-safe working environment. Finally, researchers in this study measured tests on the noise and the vibration process, and the noise caused by operations allowed for an investigation on the suitability of certain environmental conditions. Noise-related programs can be used to predict the noise distribution of the noise level characteristic. This can help identify and reduce the presence of sound interference through sound proofing measures.

중금속은 생체 내에서 분해되지 않고 장기간에 걸쳐 축적되는 특성으로 도시의 생물 다양성을 위협하는 위험한 오염물질 중 하나이다. 도시지역의 대기 중 중금속오염을 평가하기 위해 중금속 노출 정도에 따라 생물 체내의 축적농도 를 비교하는 생물학적 모니터링의 필요성이 요구되고 있다. 본 연구는 중금속 모니터링 시료로서 둥지 재료의 활용 가능성을 검토하고 중금속이 박새과 조류에 미치는 영향을 파악하기 위해 수행되었다. 연구지역은 충청남도 천안시 소재 대학교 캠퍼스 내 녹지공간(14개), 도시산림(11개), 도시공원(29개)으로 총 54개의 인공새집이 설치되었다. 조류 이용률은 도시공원 6/29개(20.68%), 캠퍼스 내 녹지공간 11/14개(78.57%), 도시산림 8/11개(72.72%)로 나타났다. 수거한 둥지로부터 이끼 재료를 채취하였고 중금속 분석을 통하여 도시녹지 유형별 중금속축적특성과 중금속이 박새과 조류의 이소 성공 여부에 미치는 영향을 비교하였다. 분석결과 아연의 평균 농도는 228.08±209.62㎍/dry g, 납의 평균 농도는 17.67±6.72㎍/dry g로 나타났다. 도시녹지 유형별 아연농도는 유의한 차이를 나타내지 않았으나(Kruskal- Wallis test, p-value=0.28) 납 농도는 유의한 차이를 보였다(Kruskal-Wallis test, p<0.05*). 중금속 분석을 진행한 21개 의 박새과 조류 둥지 중 11개(52.38%)의 둥지에서 조류의 이소가 관찰되었다. 각 도시녹지 유형에서 관찰된 조류의 이소는 캠퍼스 내 녹지공간 7개(77.78%), 도시산림 6개(85.71%), 도시공원 1개(20%)로 주로 도시산림과 캠퍼스 내 녹지공간에서 이소가 확인되었다. 박새과 조류의 이소 성공 여부에 중금속 축적특성이 미치는 영향을 확인하기 위해 중금속 농도를 비교하였으나 통계적으로 유의한 차이는 나타나지 않았다(Zn : W=44, p-value=0.74, Pb : t=0.64676, df =7.2422, p-value =0.54). 본 연구는 박새과 둥지 재료를 중금속 모니터링 시료로 사용한 기초 연구로 비침습적인 생물학적 모니터링의 기초자료로 활용될 수 있을 것으로 판단된다.