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.

PURPOSES : Demonstrated performance degradation of LiDAR for vehicle and pedestrian dummy in rainy and foggy road conditions. METHODS : In real-scale rain and fog road conditions, adjust the distance between LiDAR and the measurement target from 10m to 70m (in 10m interval), measure LiDAR NPC (number of point cloud) and intensity, and compare the resulting numerical values. RESULTS : LiDAR's NPC and Intensity showed statistically significant differences by overall weather condition (normal, rain, fog), and the values were found to be larger in the order of normal>rainfall>fog. In the case of vehicles, sunder rain conditions, NPC and intensity are recognized even at 70m as in normal conditions, but under fog conditions, NPC and intensity are measured only up to 30m. In the case of pedestrians, the reflective area size is smaller than that of vehicles, so they are recognized only up to 30m in rainy conditions, and NPC and intensity are measured only up to 20m in fog conditions. CONCLUSIONS : It was confirmed that LiDAR performance deteriorates in rain and fog compared to normal.

본 논문은 동아시아불교문화권에서 중요하게 여기고 있는 경전인 『법화경』 의 여성관에 대하여 알아본 논문이다. 『법화경』은 다양한 비유와 상징, 쉬운 표 현으로 대중적으로 널리 퍼져 신앙과 사상적으로 널리 알려진 경전이다. 본 논문에서는 『법화경』의 여성관을 알아보기 위하여 먼저 불교의 여성관을 부정적인 측면과 긍정적인 측면으로 나누어 살펴보았다. 경전에서 여성을 부정 적으로 보는 것은 비구니 팔경계, 여인오장설, 여인불성불설 등이 나타나는 부 분이다. 하지만 여성의 긍정적인 사회적 역할, 깨달음에는 성별의 차이가 없다 는 점, 여성의 몸에 보살의 지혜와 자비가 갖추어져 있다는 점, 여성이 설법하 는 점에서 긍정적으로 여성을 바라보고 있음을 알 수 있다. 여성관에 대한 이러 한 차이는 당시 인도의 사회상황과 연관되어 있으며, 수행자로서 여성을 인정 하고 깨달음을 얻을 수 있다고 한 점은 당시의 여성의 지위를 높인 것이라고 할 수 있다. 『법화경』에서는 여성에 대한 부정적인 인식도 있지만, 부처가 될 수 있는 수기를 받는다는 점에서 성불의 가능성을 볼 수 있다는 점에서 긍정적인 측면 도 보이고 있다. 경전에서는 여성의 성불에 대하여 용녀의 변성성불을 이야기 하고 있는데, 이는 종교적으로 힌두교와의 대립을 피하기 위한 것으로 생각된 다. 또한 경전에서 붓다가 이야기하는 본래 의미를 파악한다면 ‘여성의 변성성 불’이라는 글자에 얽매이지 않고 본래의 불성을 수행을 통해 드러내야 한다는 적극적인 수행방법론으로 이해해야 할 것이다. 불교에서는 일체중생의 본성은 본래 평등한 것으로서 차별이 없다고 한다. 즉, 여성도 깨달음을 얻을 수 있다는 것으로서 당시의 남성우월주의에서 벗어 나고자 한 것이다. 『법화경』의 여성관은 힌두교와의 종교적 다툼에서 벗어나기 위하여 여성성을 부정하지만 반대로 불교수행을 통한 여성의 성불가능성을 열 어주었다.

PURPOSES : LED based Variable Message Signs(VMS) have been widely used to inform safety messages to the drivers in advance. Legibility Distance of VMS is the most important factor to provide the safety messages to drivers in timely and effective way. However, current National Standards on legibility distance design considers letter size only even there is a difficulty to read the signs at adverse weather conditions such as heavy fog. So, this study examined the legibility issue under fog by evaluating the legibility distance with two design factors such as letter size and luminance. METHODS : Two foggy weather conditions, intermediate and heavy fog, were simulated at real-road-scale Proving Ground. Legibility distance at daytime and nighttime was evaluated by test subjects. Subjects were asked to fill the legible distance on the test sheet and statistical significant was analysed at the lab. RESULTS : The legibility distance(LD) under fog was observed only 22 to 41% of LD observed under normal weather condition at daytime, and 26 to 45% at nighttime condition. Study results showed a consistent increase in LD with higher luminance even at same letter size and vice versa conditions, However, statically significant difference between groups was only revealed when both letter size and luminance level increased conditions. In order to apply the test results in terms of engineering benefits, LD results from significantly different groups was evaluated with relative to Stopping Sight Distance(SSD) within conceptual frame suggested in this study. CONCLUSIONS : From the study results, current National Standard on legibility distance design needs to consider letter size and luminance simultaneously to response the legibility issue in adverse weather conditions.

In this study, machine learning models are proposed to predict the Vickers hardness of AlSi10Mg alloys fabricated by laser powder bed fusion (LPBF). A total of 113 utilizable datasets were collected from the literature. The hyperparameters of the machine-learning models were adjusted to select an accurate predictive model. The random forest regression (RFR) model showed the best performance compared to support vector regression, artificial neural networks, and k-nearest neighbors. The variable importance and prediction mechanisms of the RFR were discussed by Shapley additive explanation (SHAP). Aging time had the greatest influence on the Vickers hardness, followed by solution time, solution temperature, layer thickness, scan speed, power, aging temperature, average particle size, and hatching distance. Detailed prediction mechanisms for RFR are analyzed using SHAP dependence plots.

This study assessed the measurement technique of odorous substances using a GC/MOS system with MOS sensor at the detector and the method detection limits were determined for odorous substances such as hydrogen sulfide, acetaldehyde, toluene, m,pxylene, and o-xylene. The portable GC/MOS system was able to separate and measure about 16 out of 22 odorous substances including sulfur compounds, aldehydes, and VOCs. The peak values for hydrogen sulfide, acetaldehyde, toluene, m,p-xylene, and o-xylene showed a nonlinear relationship with concentration and a correlation coefficient of 0.95 or higher was confirmed. The method detection limits for hydrogen sulfide, acetaldehyde, toluene, m.pxylene, and o-xylene using the portable GC/MOS system were determined to be 0.005, 0.023, 0.016, 0.004, and 0.051 ppm, respectively. It is expected that the system can measure odor samples with concentrations of least 50 ppb without additional pretreatment or concentration processes.

We investigate the austenite stability in nanocrystalline Fe-7%Mn-X%Mo (X = 0, 1, and 2) alloys fabricated by spark plasma sintering. Mo is known as a ferrite stabilizing element, whereas Mn is an austenite stabilizing element, and many studies have focused on the effect of Mn addition on austenite stability. Herein, the volume fraction of austenite in nanocrystalline Fe-7%Mn alloys with different Mo contents is measured using X-ray diffraction. Using a disk compressive test, austenite in Fe–Mn–Mo alloys is confirmed to transform into strain-induced martensite during plastic deformation by a disk d. The variation in austenite stability in response to the addition of Mo is quantitatively evaluated by comparing the k-parameters of the kinetic equation for the strain-induced martensite transformation.

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.

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.

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.

중국 동북부지역 랴오닝성의 단둥(40°07'N 124°23'E)과 지린성의 궁주링(43°30'N 124°49') 및 룽징(42°46'N 129°26'E)에서 2020년과 2021년 벼 재배기간 중에 성페로몬트랩으로 이화명나방(Chilo suppressalis)(나비목: 포충나방과)의 성충 발생 시기를 조사하였다. 1화기 성충은 5월 중순부터 7월 하순 사이, 2화기 성충은 7월 중순부터 9월 중순 사이에 발생하여 세 지역 모두 연중 2회 성충 발생양상이 뚜렷하게 확인되었 다. 위도가 높은 지역에서 발생시기가 더 늦었다. 각 지역에서 관찰된 1화기 발생 시기를 기준으로 발생 시기 모델링을 통해 2화기 발생 시기를 추 정하고 관찰된 시기와 비교하였다. 네 개의 선행연구 자료로부터 성충, 알, 유충, 용 발육단계의 온도의존 생명현상(발육속도, 발육완성분포, 생존 율, 성충 노화율, 총산란수, 산란완성분포, 성충 생존완성분포) 모델들을 수집하거나 작성하였고, 이들을 선행 연구에 따라 단독으로 사용하거나 혼합하여 곤충 발생 시기 추정 소프트웨어인 PopModel에서 결합하였다. 모델링 결과에서 유충 발육기간이 짧게 관찰된 선행연구 자료를 기반으 로 하여 구성된 모형들이 2화기 성충 발생 시기를 더 근접하게 추정하였다. 2021년에는 단둥과 룽징에서 성충 조사 시기에 맞추어 이화명나방에 의 한 벼 피해주율의 변화를 조사하였다. 피해주율은 벼 재배기간 중 누적되어 2번의 증가시기가 뚜렷하게 나타났고, 이화명나방의 각 세대 유충에 의 해 발생한 것으로 추정되었다.

본 연구에서는 대추 열수추출물에 대한 유산균 발효를 통해 기능성 소재로서의 가능성을 알아보고자 하여 열수추출물에 L. plantarum 을 접종하여 유산균 발효물을 제조하였으며, 열수추출물과 유산균 발효물의 영양성분 및 항산화능을 비교 ․ 분석하였다. 대추 열수추 출물에 접종한 유산균은 초기 12시간 만에 증가하였으며, 이후 72 시간까지 큰 증감없이 그 수를 유지하여 대추 열수추출물은 유산균 의 생육에 큰 영향을 미치지 않았다. 열수추출물과 유산균 발효물 의 당도, pH 및 총산도를 측정한 결과, 당도는 유산균 발효 여부와 관계없이 열수추출횟수가 증가할수록 높아졌으며, pH는 유산균 발 효 이후 현저히 감소하였고, 총산도는 2차 열수추출물의 발효물에 서만 유의적으로 증가하였다. 2차 열수추출물의 유산균 발효 여부 에 따른 일반영양성분 분석 결과, 모든 성분에서 유의적 차이를 보 이지 않았으며, DPPH 및 ABTS free radical 소거활성능은 유산 균 발효 여부에 관계없이 열수 추출횟수에 비례하여 증가하여 2차 열수추출물과 그의 발효물에서 가장 높은 결과를 나타내었다. 총폴 리페놀 함량 또한 유산균 발효여부에 관계없이 1차 열수추출물에 서 가장 높은 값이 관찰되었다. 본 연구를 통해 대추 열수추출물은 유산균 생육에 전혀 영향을 미치지 않아 유산균 발효물 제조 가능 성을 확인했으며, 또한 항산화능과 총폴리페놀 함량은 열수추출횟 수에 의해 영향을 받는다는 사실을 알 수 있었다. 하지만, 열수추출 물과 유산균 발효물 사이에 일반영양성분 및 항산화능에 큰 차이 는 없었으며, 이는 L. plantarum 단일 균주로만 연구를 진행했기 때문으로 여겨진다. 따라서 추후에 다양한 유산균주를 사용하여 대추 열수추출물의 발효를 시도해 항산화능을 비롯한 다양한 기능 성을 증가시킬 수 있는 유산균주를 탐색할 필요가 있을 것으로 사 료된다.

A new Fe-Cr-Mo-B-C amorphous alloy is designed, which offers high mechanical strength, corrosion resistance as well as high glass-forming ability and its gas-atomized amorphous powder is deposited on an ASTM A213-T91 steel substrate using the high-velocity oxygen fuel (HVOF) process. The hybrid coating layer, consisting of nanocrystalline and amorphous phases, exhibits strong bonding features with the substrate, without revealing significant pore formation. By the coating process, it is possible to obtain a dense structure in which pores are hardly observed not only inside the coating layer but also at the interface between the coating layer and the substrate. The coating layer exhibits good adhesive strength as well as good wear resistance, making it suitable for coating layers for biomass applications.

The effect of the process conditions of high-velocity oxygen fuel (HVOF) thermal spray coating on the porosity of the coating layer is investigated. HVOF coating layers are formed by depositing amorphous FeMoCrBC powder. Oxygen pressure varies from 126 to 146 psi and kerosene pressure from 110 to 130 psi. The Microstructural analysis confirms its porosity. Data analysis is performed using experimental data. The oxygen pressure-kerosene pressure ratio is found to be a key contributor to the porosity. An empirical model is proposed using linear regression analysis. The proposed model is then validated using additional test data. We confirm that the oxygen pressure-kerosene pressure ratio exponentially increases porosity. We present a porosity prediction model relationship for the oxygen pressure-kerosene pressure ratio.