과불화화합물(PFAS)은 높은 화학적⋅열적 안정성으로 인해 환경에서 쉽게 분해되지 않고 축적되며, 생식 독성, 내분비계 장애 등 다양한 유해성을 나타내 글로벌 규제의 중심에 있다. 특히 반도체 제조 산업은 PFAS 계열 화학물질을 공정 중 직접 사용하거나 부산물 형태로 배출하고 있어, 이들 물질의 배출 현황과 특성에 대한 면밀한 관찰과 관리가 필수적이다. 본 연구는 반도체 제조 공정에서 발생 가능한 PFAS의 배출 경로를 공정 단계별로 체계적으로 분석하고자 하였다. 이를 위해 반도체 공정 중 PFAS의 사용 및 유출 가능성이 높은 포토 공정, 습식 화학 공정, 건식 화학 공정을 구분하여 각 단계에서 PFAS가 어떤 방식으로 사용되고 어떤 경로로 배출되는지를 체계적으로 검토하였다. 분석 결과, 포토 공정에서는 포토레지스트에 포함된 광산발생제를 통해 PFAS가 직접적으로 사용되는 것으로 나타났으며, 습식 공정에서는 식각 및 세정 단계에서 PFAS 계면활성제가 폐수로 유입되는 경로를 확인하였다. 건식 공정에서는 불소계 가스 및 리간드(Ligand) 물질이 간접적인 PFAS 발생원으로 작용할 수 있으며, 공정 내 화학적 분해 반응을 통해 형성되는 PFAS 유사물질의 배출 또한 고려할 필요가 있음을 밝혔다. 본 연구는 반도체 제조 공정에서의 PFAS 배출 특성을 공정 구조와 연계하여 통합적으로 분석함으로써, 향후 PFAS 저감 기술 개발 및 규제 대응을 위한 기술적⋅제도적 관리 방안 수립을 위한 기초 자료로 활용될 수 있을 것으로 기대된다.

과불화화합물(PFAS)은 우수한 내열성, 발수성, 내유성을 지닌 합성 화학물질로, 다양한 산업 분야에서 광범위하게 사용되어 왔다. 그러나 이러한 무분별한 사용은 PFAS의 높은 화학적 안정성과 생물학적 축적성을 초래하며, 반도체 산업을 포함한 다양한 산업 활동에서 배출되는 폐수를 통해 생태계와 인류 건강에 심각한 위협을 초래하고 있다. 본 연구는 PFAS 중 대표적인 과불화옥탄산(PFOA)와 과불화옥탄설폰산(PFOS)를 중심으로 다양한 수처리 기술을 검토⋅분류하고, 각 기술의 메커니즘, 최신 연구 사례, 한계점 등을 종합적으로 분석하였다. 물리적 처리 기술로는 입상 및 분말 형태의 활성탄을 활용한 흡착법과, 나노여과(NF) 및 역삼투(RO)를 기반으로 한 막여과 기술이 포함되며, 화학적 처리 기술로는 고도 산화⋅환원 공정, 특히 붕소 도핑 다이아몬드(BDD) 전극을 이용한 전기화학적 산화 기술에 중점을 두었다. 이외에도 생물학적 처리 기술, Feammox 반응, 이온 교환 수지, 플라즈마 처리 등의 최신 기술의 적용사례와 PFAS 제거 메커니즘을 분석하였다. 특히, 최근에는 개별 기술의 한계를 보완하기 위한 상호보완적 융합 방식의 복합 공정 전략이 주목받고 있다. 본 논문은 이와 같이 다양한 수처리 기술에 대한 연구 동향을 분석함으로써, PFAS 제거를 위한 수처리 기술에 대한 통합적 이해와 실질적인 적용 가능성에 대한 통찰을 제공하고자 한다.

본 연구의 목적은 ‘아동학대 예방 및 피해아동 보호 조례’ 비교·분석을 통해 아동학대를 예방하고 피해아동을 보호하기 위한 조례 개정 방안을 제시하는 것이다. 이를 위해 충청북도 및 6개 기초자치단체 조례를 사회 복지조례의 내용적 체계 비교 분석틀에 기초하여 비교·분석하였다. 분석 결과, 충청북도 조례는 적용대상, 재정부담, 벌칙 구성요소에서, 충주시 조례는 권리성, 적용대상, 전달체계, 인력 구성요소에서 가장 체계적이었 다. 조례 개정 방안으로 학대피해아동쉼터 운영 조항을 ‘지정’이 아닌 ‘운영’으로 개정, 단체장의 책무로써 재정적 지원 명시 및 예산 지원 강 행규정으로 변경, 인력의 전문성 강화를 위한 아동학대 전담공무원 임용 및 필수 보직기간 설정을 제시하였다.

We investigated the microstructure of an FeCrMnNiCo alloy fabricated by spark plasma sintering under different sintering temperatures (1000–1100°C) and times (1–600 s). All sintered alloys consisted of a single face-centered cubic phase. As the sintering time or temperature increased, the grains of the sintered alloys became partially coarse. The formation of Cr7C3 carbide occurred on the surface of the sintered alloys due to carbon diffusion from the graphite crucible. The depth of the layer containing Cr7C3 carbides increased to ~110 μm under severe sintering conditions (1100°C, 60 s). A molten zone was observed on the surface of the alloys sintered at higher temperatures (>1060°C) due to severe carbon diffusion that reduced the melting point of the alloy. The porosity of the sintered alloys decreased with increasing time at 1000°C, but increased at higher temperatures above 1060°C due to melting-induced porosity formation.

The effects of annealing on the microstructure and mechanical properties of Al–Zn–Mg–Cu–Si alloys fabricated by high-energy ball milling (HEBM) and spark plasma sintering (SPS) were investigated. The HEBM-free sintered alloy primarily contained Mg2Si, Q-AlCuMgSi, and Si phases. Meanwhile, the HEBM-sintered alloy contains Mg-free Si and θ-Al2Cu phases due to the formation of MgO, which causes Mg depletion in the Al matrix. Annealing without and with HEBM at 500oC causes partial dissolution and coarsening of the Q-AlCuMgSi and Mg2Si phases in the alloy and dissolution of the θ-Al2Cu phase in the alloy, respectively. In both alloys, a thermally stable α-AlFeSi phase was formed after long-term heat treatment. The grain size of the sintered alloys with and without HEBM increased from 0.5 to 1.0 μm and from 2.9 to 6.3 μm, respectively. The hardness of the sintered alloy increases after annealing for 1 h but decreases significantly after 24 h of annealing. Extending the annealing time to 168 h improved the hardness of the alloy without HEBM but had little effect on the alloy with HEBM. The relationship between the microstructural factors and the hardness of the sintered and annealed alloys is discussed.

Radish is an important root vegetable in the world, and many cultivars have been developed with various molecular marker systems to identify these cultivars. Recently developed markers for radish cultivar identification require only 11 primer pairs, but they still use conventional PCR with different annealing temperatures and time-consuming gel electrophoresis. To improve the genotyping method, we applied touchdown PCR with 11 primers with M13 tails among 105 radish cultivars. Touchdown PCR successfully generated amplicons in all 11 M13-tailed primers with a condition of annealing temperature starting from 55℃, decreased by 1°C and 33 cycles at 53°C. The 11 M13-tailed primers followed by fragment analysis produced 71 amplicons, which produced more amplicons than gel electrophoresis that produced 23 amplicons. Especially, simple sequence repeats produced more amplicons, 12 on average, than the other marker types. The present study requires less effort and provides more accurate results compared to genotyping using gel electrophoresis. Besides, a database can be established using digitized genotyping results among radish cultivars.

Changes in the mechanical properties and microstructure of an IN 939 W alloy according to the sintering heating rate were evaluated. IN 939 W alloy samples were fabricated by spark plasma sintering. The phase fraction, number density, and mean radius of the IN 939W alloy were calculated using a thermodynamic calculation. A universal testing machine and micro-Vickers hardness tester were employed to confirm the mechanical properties of the IN 939W alloy. X-ray diffraction, optical microscopy, field-emission scanning electron microscopy, Cs-corrected-field emission transmission electron microscopy, and energy dispersive X-ray spectrometry were used to evaluate the microstructure of the alloy. The rapid sintering heating rate resulted in a slightly dispersed γ' phase and chromium oxide. It also suppressed the precipitation of the η phase. These helped to reinforce the mechanical properties.

A typical trade-off relationship exists between strength and elongation in face-centered cubic metals. Studies have recently been conducted to enhance strength without ductility reduction through surface-treatment-based ultrasonic nanocrystalline surface modification (UNSM), which creates a gradient microstructure in which grains become smaller from the inside to the surface. The transformation-induced plasticity effect in Fe-Mn alloys results in excellent strength and ductility due to their high work-hardening rate. This rate is achieved through strain-induced martensitic transformation when an alloy is plastically deformed. In this study, Fe-6%Mn powders with different sizes were prepared by high-energy ball milling and sintered through spark plasma sintering to produce Fe-6%Mn samples. A gradient microstructure was obtained by stacking the different-sized powders to achieve similar effects as those derived from UNSM. A compressive test was performed to investigate the mechanical properties, including the yielding behavior. The deformed microstructure was observed through electron backscatter diffraction to determine the effects of gradient plastic deformation.

An alternative fabrication method for carburizing steel using spark plasma sintering (SPS) is investigated. The sintered carburized sample, which exhibits surface modification effects such as carburizing, sintered Fe, and sintered Fe–0.8 wt.%C alloys, is fabricated using SPS. X-ray diffraction and micro Vickers tests are employed to confirm the phase and properties. Finite element analysis is performed to evaluate the change in hardness and analyze the carbon content and residual stress of the carburized sample. The change in the hardness of the carburized sample has the same tendency to predict hardness. The difference in hardness between the carburized sample and the predicted value is also discussed. The carburized sample exhibits a compressive residual stress at the surface. These results indicate that the carburized sample experiences a surface modification effect without carburization. Field emission scanning electron microscopy is employed to verify the change in phase. A novel fabrication method for altering the carburization is successfully proposed. We expect this fabrication method to solve the problems associated with carburization.

This study examines the effect of microstructural factors on the strength and deformability of ferrite-pearlite steels. Six kinds of ferrite-pearlite steel specimens are fabricated with the addition of different amounst of Mn and V and with varying the isothermal transformation temperature. The Mn steel specimen with a highest Mn content has the highest pearlite volume fraction because Mn addition inhibits the formation of ferrite. The V steel specimen with a highest V content has the finest ferrite grain size and lowest pearlite volume fraction because a large amount of ferrite forms in fine austenite grain boundaries that are generated by the pinning effect of many VC precipitates. On the other hand, the room-temperature tensile test results show that the V steel specimen has a longer yield point elongation than other specimens due to the highest ferrite volume fraction. The V specimen has the highest yield strength because of a larger amount of VC precipitates and grain refinement strengthening, while the Mn specimen has the highest tensile strength because the highest pearlite volume fraction largely enhances work hardening. Furthermore, the tensile strength increases with a higher transformation temperature because increasing the precipitate fraction with a higher transformation temperature improves work hardening. The results reveal that an increasing transformation temperature decreases the yield ratio. Meanwhile, the yield ratio decreases with an increasing ferrite grain size because ferrite grain size refinement largely increases the yield strength. However, the uniform elongation shows no significant changes of the microstructural factors.

The objective of this study was to evaluate the effectiveness of various crack inducers to be used in the advanced reinforced concrete pavement (ARCP) by conducting yard tests. Some of cracks are induced in ARCP to reduce the stresses in steel bars and to form more uniformly spaced cracks so that the required steel bar amount can be decreased and at the same time the pavement performance can be improved. In this study, an experimental ARCP was constructed for the length of 22.4 m, width of 1.12 m, and thickness of 0.26 m. The anchor lugs were placed at both ends of ARCP to pretend continuities of the system. 8 crack inducers with a uniform spacing of 2.8 m were installed in different manners when placing concrete, so the test length of the experimental ARCP was 19.6 m. The variables of crack inducers included the shape, material, installed depth, and installing method. The basic shape of the crack inducer represented a round face and a flat opposite face with a height of 50 mm and a width of 10 mm. The slightly different shaped crack inducers were installed for inducing cracks at both ends of ARCP. The crack inducers were primarily made of glass fiber reinforced plastic (GFRP) but a crack was induced using a polyethylene sheet inducer. The installed depths of the crack inducers were 30, 40 and 70 mm to the top of the crack inducer from the pavement surface. Most crack inducers were preinstalled on the transverse steel bar locations before concrete pouring, but 2 crack inducers were installed just after concrete placement when concrete was still fresh. The temperature measurement sensors of i-Buttons and thermocouples were installed at the top, middle and bottom of slab to measure the temperature variations of slab. The displacement transducers were also installed at the crack locations to measure the crack width movements. The experimental results showed that the cracks were induced at all the locations where the crack inducers were placed. In addition to the induced cracks, just one crack was formed naturally. The crack patterns on the surface of pavement were all comparable. The crack width measurement data showed that there were slight differences in the crack width movements among the cracks but all the cracks including both the induced and naturally formed cracks moved little within a 0.1 mm range. Therefore, any type of the crack inducers employed in this study can be used to initiate cracks in ARCP.