기후변화 위기에 대응하기 위하여 우리나라는 국가 온실가스 감축 목표로 2030년까지 온실가 스 배출량을 2018년 대비 40% 감축을 목표로 제시하였으며, 수송부문은 37.8% 감소한 61백만톤CO2eq으 로 제시하였다. 온실가스 배출량 감축 방안 중 신‧재생에너지 연료 혼합의무화제도(RFS)에 따른 수송용 연 료의 바이오디젤 혼합의무비율을 2030년까지 기존 5%에서 8%로 상향한다는 계획을 제시하였다. 그러나 국내에 상용화되어 있는 기존 바이오디젤은 원료에 따라 품질이 크게 좌우되며 저온 특성, 산화안정성 등 의 문제로 혼합비율 상향에는 한계가 있다. 본 연구에서는 이를 극복하기 위해 수첨바이오디젤과 기존 바 이오디젤의 품질을 비교하고 자동차용 경유에 혼합하여 물리적 특성을 살펴보았다. 수첨바이오디젤의 필터 막힘점은 –35 ℃으로 측정되었으며 기존 바이오디젤과 비교하여 저온 특성이 우수한 것을 확인할 수 있었 다. 또한 자동차용 경유에 기존 바이오디젤과 수첨바이오디젤을 최대 12%까지 혼합하여 영향성을 분석하 였으며 국내 자동차용 경유 품질기준의 주요 항목을 만족하는 것을 확인할 수 있었다. 이번 연구 결과를 통해 수첨바이오디젤의 국내 상용화를 위한 기술적 기초자료를 제시하고 신규 석유대체연료로서의 적용 가능성을 확인하고자 하였다.

In this study, Cu was added in amounts of 0, 0.5, and 1 wt% to Al-1Zn-0.5MM-0.3Mg alloys to investigate its effects on phase formation, microstructural evolution, recrystallization behavior, and mechanical properties under as-cast and extruded conditions. Additional Al2Cu phases appeared with increasing Cu addition. EBSD (electron backscatter diffraction) analysis of the extruded alloys revealed that the average grain size boundaries [HAGB (high angle grain boundary), > 15°] increased from 0.124 to 0.299, confirming recrystallization was significantly enhanced by the addition of 1 wt% Cu. Furthermore, the maximum ODF(orientation distribution function) intensity decreased from 6.597 to 3.88 (M.R.D.), indicating that the crystallographic texture became more randomized as recrystallization progressed. Tensile testing showed that the yield strength (YS) and ultimate tensile strength (UTS) increased from 56.28 to 62.28 MPa and from 91.58 to 152.73 MPa, respectively, due to grain refinement and both solid-solution and precipitation strengthening by Cu. These findings demonstrate that adding Cu effectively controls phase formation, recrystallization, and mechanical properties in Al-Zn-MM-Mg alloys.

Ammonia (NH3) emitted from swine manure contributes to odor problems and environmental pollution in intensive livestock systems. Plant extracts containing natural saponins, such as Yucca schidigera (YS) and Quillaja saponaria (QS), are used as potential agents to reduce gaseous emissions. This study evaluated the effect of a YS–QS powdered extract on NH3 emissions from pig manure under controlled laboratory conditions. Nine cylindrical pots (23 cm diameter, 25 cm height) were filled with 5 kg of fresh pig manure and assigned to three treatments with three replicates each: untreated manure (T0), manure plus 250 mg/kg extract (T250), and manure plus 2,500 mg/kg extract (T2500). Pots were maintained at 30°C in insulated containers. The extract consisted of a commercially available YS–QS powder. Initial manure properties were pH 8.19 and oxidation-reduction potential –60 mV. Headspace NH3 concentrations were continuously measured using a multi-channel laser-based gas analyzer at ~67-second intervals. Based on the results, NH3 concentrations at day 0 for T0, T250, and T2500 were 35.31±11.07, 62.03±24.30, and 84.65±21.11 ppb, respectively. By day 2, the concentrations decreased to 29.40±12.69, 41.59±18.92, and 50.40±18.81 ppb. The overall reduction rates from day 0 to day 2 were 17% (T0), 33% (T250), and 40% (T2500), with T250 achieving approximately twice the reduction observed in T0. In conclusion, the YS–QS extract reduced NH3 emissions from pig manure, with treatments ≥250 mg/kg showing greater effectiveness than the untreated manure. These results support the potential use of plant-based additives to improve NH3 emission control in manure.

Designing long-wavelength emissive carbon dots (CDs) with high photoluminescence quantum yield (PL QY) is an inevitable component for lighting applications. However, it is still challenging to develop an efficient CDs with excitation-independent emission in long-wavelength regions. In this work, we developed an excitation-independent yellow emissive CD (y-CDs) with PL emission centered at 568 nm via a facile solvothermal treatment of citric acid and melamine using toluene as solvent. The synthesized, y-CDs contain a high degree of conjugated sp2- carbon domains (fused rings) with different surface groups, which serve as a center for photon absorption. The addition of melamine improves the degree of sp2- conjugated carbon domain and surface groups thereby switching the emission of y-CDs from excitation-dependent to excitation-independent emission with excellent PL QY of 80.2%, UV stability, and large Stoke shift. This work not only developed an efficient yellow emissive CD but also explored the possible mechanism of excitation-independent emission and used it for the development of phosphor-converted LEDs. The LED shows warm yellow light with CIE coordinates of (0.48, 0.49), CCT of 2983 K, excellent color purity of 94%, and high thermal stability. This study promotes the development of cost-effective and ecofriendly optoelectronic devices for smooth lighting applications.

This study investigates the vitrification of blast furnace slag (BFS) by adjusting the content of steel slag and the added amount of E-glass. SaEb glasses were prepared with a composition of x wt% BFS and (100-x) wt% E-glass (x = 10, 20, 30, 40, and 50). Each composition was melted in a platinum crucible under atmospheric conditions at 1,500 °C for 2 h, and transparent glasses with a transmittance exceeding 75 % were fabricated. All SaEb glasses exhibit an amorphous pattern, indicating successful vitrification. We also analyzed their optical, thermal, and physical properties, including Fourier transform infrared spectroscopy (FT-IR), glass transition temperature (Tg), and x-ray pattern. As the E-glass content increased, the glass transition temperature of blast furnace slag-based glass decreased from 765 °C to 734 °C due to the weakening of the SiO4 unit structure. In all compositions, the glass transition–crystallization temperature difference exceeded 220 °C, confirming the glasses stability for slag fiber applications. The blast furnace slag-based glass exhibits potential for application in slag fiber production, and is expected to provide fundamental data for future studies on related materials.

This study aimed to evaluate the effect of partially replacing pork backfat with string cheese on the quality of dry-cured goat meat sausages. Two formulations were prepared: A control (C0, 20% backfat) and a treatment (C10), in which 10% backfat was replaced with string cheese. Proximate composition, fatty acid profile, thiobarbituric acid reactive substances (TBARS), pH, water activity, color, and texture were analyzed. The addition of string cheese significantly reduced fat and increased protein and moisture (p<0.05). Fatty acid analysis revealed higher medium-chain saturated fatty acids (C4:0- C8:0) and total saturated fatty acids (SFA), with a lower unsaturated-to-saturated fatty acid (UFA/SFA) ratio. Both groups showed TBARS values below the sensory threshold, but the treatment had significantly lower lipid oxidation (p<0.05). The treatment also had a higher pH, while water activity showed no difference. In color, the treatment exhibited significantly higher a* (redness) and b* (yellowness) values. Textural analysis indicated increased hardness but reduced cohesiveness and gumminess. These findings suggest string cheese can act as a fat replacer and functional ingredient that improves the nutritional and physicochemical characteristics of dry-cured goat sausages.

본 연구에서는 고분자 점도 조절제를 첨가하여 졸-겔법 기반 알루미나 나노여과막을 단일 공정으로 제조하고, 코 팅층의 구조 및 성능을 제어하는 방법을 제시하였다. Hydroxypropyl cellulose (HPC, Mw ~80000) 고분자를 알루미나 졸에 첨가하여 점도를 10 mPa·s에서 최대 4200 mPa·s까지 조절하였으며, 이를 통해 알루미나 중공사 지지체 표면에 균일하고 결 함이 없는 선택층을 형성하였다. HPC 함량이 증가할수록 코팅층 두께가 증가하였으나, 기공 크기 증가에 따라 분리 성능이 저하되었다. 2:1 (졸:HPC 고분자 용액) 혼합비에서 제조된 나노여과막은 두께 3.20 μm의 얇은 선택층을 형성하여 높은 수투 과도(12.9 LMH/bar)와 우수한 제거 성능(PPG 1050 Da 제거율 60%, PEG 1500 Da 제거율 90%, MgCl2 제거율 80%)을 나타 냈다. 반면, 1:2 혼합비에서는 선택층 두께가 10.2 μm로 증가하였으나, 기공 크기가 증가하여 3400 Da MWCO와 64% 염 제 거율을 보였다. HPC 고분자를 활용한 점도 제어는 졸-겔 코팅층의 두께, 기공 구조 및 분리 성능을 효과적으로 조절할 수 있 음을 입증하였다.

막여과 장치에 분말활성탄, 입상활성탄 및 안트라사이트를 투입하여 막여과 장치의 파울링 저감 및 막차압 개선효과에 대한 실험을 실시하였다. 막의 fouling 저감을 위해 투입되는 입자의 사이즈 가 보다 중요한 인자가 되는 것으로 조사되었다. 막차압과 활성탄 주입량에 따른 총 여과저항값은 활성 탄의 투입량이 증가할수록 총 여과저항값은 조금씩 감소하는 경향을 나타내었다. 총 여과저항값에서 막 저항값을 배제한 활성탄만의 여과저항값은 활성탄의 투입량이 증가할수록 여과저항값이 감소하는 것으 로 조사되었다. Cross-flow나 dead-end나 운전방식에 따라 처리효율에 차이는 나타나지만, 막여과에 활성탄을 투입함으로써 fouling 억제효과와 함께 활성탄의 흡착효과도 동시에 얻을 수 있음을 확인할 수 있었다.

Aluminum nitride (AlN) provides excellent thermal conductivity and electrical insulation, making it suitable for semiconductor heater applications. However, its low surface emissivity can lead to thermal energy loss, reducing heater efficiency. To address this issue, black AlN - obtained by doping with carbon and other impurities to enhance the surface emissivity - has recently been applied in various fields. In this study, black AlN was fabricated by adding TiO2 to AlN, and its densification behavior and electrical properties were evaluated to assess the feasibility of its use as a heater material for semiconductor photolithography. The sinterability of black AlN was improved by optimizing the granulation and forming conditions, with a particular focus on the heat treatment parameters that affect material properties such as color. Consequently, a black AlN heater material with a sintered density of 3.33 g/cm3, thermal conductivity of 162.7 W/m･K, and thermal diffusivity of 64.22 mm2/s was fabricated by optimizing the processing variables.

목적 : 본 연구는 사진 계측법과 스마트 센터링 장치 계측법을 사용하여 누진 굴절력 렌즈 처방을 위한 누진대 길이와 매개변수 측정에 활용할 수 있는 자료를 제공하고자 하였다. 방법 : 사진 계측 장치를 이용하여 누진 굴절력 렌즈 처방에 필요한 매개변수인 광학 중심점 높이, 정점 간 거 리, 경사각, 안면각을 측정하였다. 또한 근거리 작업 자세를 분석하여 누진대 길이 처방에 참고 값으로 활용할 수 있는 하방 안구 이동량을 산출하였다. 이후 측정한 매개변수와 하방 안구 이동량을 스마트 센터링 장치를 이용하여 측정한 값과 비교하였다. 결과 : 원거리 및 근거리에서 나안으로 광원을 인지할 수 있는 시력 이상의 성인 남녀 25명을 대상으로 하였다. 사진 계측법을 이용하여 산출한 하방 안구 이동량은 평균 10.12±3.33 mm로 측정되었으며, 작업 거리가 짧아질수 록 길게 측정되었다(r=-0.418, p<0.050). 사진 계측법과 스마트 센터링 장치 측정법의 매개변수 측정값을 비교한 결과, 원거리 및 근거리 작업 거리에서 단안과 양안의 동공 중심 간 거리와 안면각은 통계학적으로 유의한 차이가 없었으나(p>0.050) 수직적인 머리 움직임에 영향을 많이 받는 광학 중심점 높이, 정점 간 거리, 경사각은 유의한 차이가 있었다(p<0.050). 하방 안구 이동량은 스마트 센터링 장치로 측정한 값이 9.67±1.99 mm로 사진 계측법 으로 측정한 값보다 0.46±3.35 mm 더 작게 측정되었으나, 통계학적으로 유의한 차이는 없었다(p>0.050). 결론 : 본 연구는 근거리 작업 자세와 하방 안구 이동량을 분석하고 사진 계측법과 스마트 센터링 장치 측정법 을 비교하여 누진 굴절력 렌즈 처방에 필요한 누진대와 매개변수 측정에 대한 기초 자료를 제시하였다.

This study investigated whether calcium (Ca) addition improved the recovery of neodymium (Nd) and dysprosium (Dy) from Nd-Fe-B magnet scrap using magnesium (Mg)-based liquid metal extraction (LME). Traditional LME processes are limited to temperatures up to 850 °C due to oxidation issues, reducing the efficiency of rare earth element (REE) recovery, especially for Dy. By adding 10 wt.% Ca to Mg and increasing the processing temperature to 1,000 °C, we achieved nearly 100% Nd and approximately 38% Dy recovery, compared to 91% and 28%, respectively, with pure Mg at 850 °C. However, excessive Ca addition (20 wt.%) decreased the recovery efficiency due to the formation of stable intermetallic compounds. These results highlight the critical role of Ca in optimizing REE recycling from Nd-Fe-B magnet scrap.

목적 : 누진 가입도 안경 착용자의 안경테의 크기와 얼굴 형태에 적합한 안경테를 비교하여 안경테 크기와 신체 적(역학적) 불편감 사이의 연관성을 조사하였다. 방법 : 누진 가입도 안경 착용자 중 안경의 피팅 상태가 적절한 71명(남성 37명, 여성 34명, 평균 54.52±8.78 세)이 참여하였고, 신체적 불편감을 설문지로 조사하였다. 안경테 크기를 FHD(front horizontal dimension), FTB(front to bend), LOD(length of drop) 및 TL(temple length)로 확인하였다. 얼굴 형태를 계측한 후 얼굴에 적합한 안경테 크기를 계산하였고, 착용하고 있는 안경테 크기와 비교하였다. 결과 : 신체적 불편감의 정도는 관자놀이 눌림, 흘러내림, 코 눌림, 귀 눌림 순으로 높았으며, 불편함을 경험한 비율은 흘러내림, 코 눌림, 귀 눌림, 관자놀이 눌림 순으로 높았다. 착용한 안경테의 FHD는 남녀 모두 얼굴 계측 으로 계산한 안경테 설계값보다 작았다(p=0.001). 착용한 안경테의 FTB는 남녀 모두 안경테 설계값보다 작았으 며, 착용한 안경의 LOD는 설계값보다 컸고 여성은 남성보다 길었다(all, p=0.001). 결론 : 착용한 남녀 안경의 FHD는 얼굴 형태에 비해 작아 관자놀이 눌림의 원인이 될 수 있고, 측면부 LOD는 얼굴에 비해 커서 흘러내림과 코 눌림의 원인이 될 수 있다. 얼굴 형태에 적합한 안경테 크기를 선택할 수 있도록 안경테의 FHD와 측면부 전체 길이(FTB+LOD)가 여러 사이즈로 제작되어야 할 것이다.

Nitrogen-doped carbon nanomaterials (N-CNMs) were prepared using Ni(NO3)2 as a catalyst in the laminar diffusion flame. Doping the structure of carbon nanomaterials (CNMs) with nitrogen can significantly change the characteristics of CNMs. The purpose of this research is to study the effect of adding ammonia ( NH3) on the evolution of CNMs structure in the laminar flame of ethylene. Raman analysis shows that the intensity ratio ( ID/IG) of the D-band and G-band of N-CNMs increases and then decreases after the addition of NH3. The intensity ratio is a maximum of 0.99, which has a good degree of disorder and defect density. The binding distribution of nitrogen was analyzed by X-ray photoelectron spectroscopy (XPS), and a correlation was found between the amount of nitrogen and the morphology of N-CNMs. Nitrogen atoms predominantly present in the forms of pyrrolic-N, pyridinic-N, graphitized-N and oxidized-N, with a doping ratio of nitrogen atoms reaching up to 2.44 at.%. This study found that smaller nickel (Ni) nanoparticles were the main catalysts for carbon nanotubes (CNTs), and their synthesis followed the ‘hollow growth mechanism’ and carbon nanofibers (CNFs) were synthesized from larger Ni nanoparticles according to the ‘solid growth mechanism’. Furthermore, a growth mechanism for the synthesis of bamboolike CNTs using a specific particle size of the Ni catalyst is proposed. It is noteworthy that the synthesis and modulation of high-performance N-CNMs by flame method represents a simple and efficient approach.

Super-duplex stainless steels are in great demand in various industrial fields such as chemical processing and seawater desalination due to their excellent pitting corrosion resistance. However, detrimental phases can easily form during fabrication, and even minor additions of alloying elements can significantly impact their microstructure and properties. This study investigated the effects Cu or Ti additions on a super-duplex stainless steel. First, the effects of annealing time at 950 °C on the microstructure and corrosion characteristics were investigated. It was found that as the annealing time increased, the fraction of sigma phase increased; however, the corrosion resistance in the electrochemical test using a 3.5 % NaCl electrolyte showed only a slight improvement. The microstructure of duplex stainless steel with added Cu or Ti did not differ significantly from that of the base steel. However, the overall corrosion resistance showed improvement, and in particular, an observed increase in pitting potential. Investigating the characteristics of the passive film on the alloy surface revealed that the stability of the passive film was higher in alloys with added Cu or Ti compared to the standard alloy. Among these, the alloy with Cu addition had the thickest film, while the Ti-added alloy had the highest Cr concentration and a film thickness greater than that of the standard alloy.

This study investigated the effects of starch addition and type on the characteristics of extruded products of floury rice powder (FRP). Native starches from waxy, normal, and high-amylose corn, wheat, tapioca, and potatoes were used. Each starch replaced 30% of the dry weight of FRP. FRP and FRP-starch mixtures were extruded using a twin screw extruder at 19–20% moisture content, 18 Hz screw speed, and barrel temperature of 160℃, followed by drying at 80℃ for 3 h. The water absorption and water solubility indices of the FRP-starch mixtures were higher than those of starch alone, whereas swelling power exhibited the opposite trend. The gelatinization temperatures of the FRP-starch mixtures, except for the FRP-wheat starch mixture, shifted to higher temperatures than those of FRP, whereas their gelatinization enthalpies were lower. The pasting viscosities of the FRP-starch mixtures, except for the FRP-high-amylose cornstarch mixture, were higher than those of FRP. Regarding the extruded products, partial replacement of FRP with starch improved the expansion ratio and specific volume of the extrudates. The failure strength, measured using a 3-point bending test, was higher for the FRP-starch mixture (except for high-amylose corn and tapioca starches) than for FRP.