Metal additive manufacturing (AM) facilitates the production of complex geometries with enhanced functionality. Among various AM techniques, laser powder bed fusion (LPBF) is distinguished by its precision and exceptional mechanical properties achieved via laser fusion deposition. Recent advancements in AM have focused on combining LPBF with post-processing methods such as cold rolling, high-pressure torsion, and forming processes. Therefore, understanding the forming behavior of LPBF-processed materials is essential for industrial adoption. This study investigates the stretch-flangeability of LPBF-fabricated 316L stainless steel, emphasizing its anisotropic microstructure and mechanical properties. Hole expansion tests were employed to assess stretch-flangeability in comparison to wrought 316L stainless steel. The results demonstrate that LPBF-processed samples exhibit significant anisotropic behavior, demonstrating the influence of microstructural evolution on formability. These findings contribute valuable insights into optimizing LPBF materials for industrial forming applications.
High-entropy alloys (HEAs) have been reported to have better properties than conventional materials; however, they are more expensive due to the high cost of their main components. Therefore, research is needed to reduce manufacturing costs. In this study, CoCrFeMnNi HEAs were prepared using metal injection molding (MIM), which is a powder metallurgy process that involves less material waste than machining process. Although the MIM-processed samples were in the face-centered cubic (FCC) phase, porosity remained after sintering at 1200°C, 1250°C, and 1275°C. In this study, the hot isostatic pressing (HIP) process, which considers both temperature (1150°C) and pressure (150 MPa), was adopted to improve the quality of the MIM samples. Although the hardness of the HIP-treated samples decreased slightly and the Mn composition was significantly reduced, the process effectively eliminated many pores that remained after the 1275°C MIM process. The HIP process can improve the quality of the alloy.
In this study, we introduce a novel TiN/Ag embedded TiO2/FTO resistive random-access memory (RRAM) device. This distinctive device was fabricated using an environmentally sustainable, solution-based thin film manufacturing process. Utilizing the peroxo titanium complex (PTC) method, we successfully incorporated Ag precursors into the device architecture, markedly enhancing its performance. This innovative approach effectively mitigates the random filament formation typically observed in RRAM devices, and leverages the seed effect to guide filament growth. As a result, the device demonstrates switching behavior at substantially reduced voltage and current levels, heralding a new era of low-power RRAM operation. The changes occurring within the insulator depending on Ag contents were confirmed by X-ray photoelectron spectroscopy (XPS) analysis. Additionally, we confirmed the correlation between Ag and oxygen vacancies (Vo). The current-voltage (I-V ) curves obtained suggest that as the Ag content increases there is a change in the operating mechanism, from the space charge limited conduction (SCLC) model to ionic conduction mechanism. We propose a new filament model based on changes in filament configuration and the change in conduction mechanisms. Further, we propose a novel filament model that encapsulates this shift in conduction behavior. This model illustrates how introducing Ag alters the filament configuration within the device, leading to a more efficient and controlled resistive switching process.
해사영어는 선박 운항, 해양 안전, 선내 의사소통 및 선외 교신을 위해 설계된 특수한 영어 언어체계이다. 국제해사기구 STCW(선원의 훈련, 자격증명 및 당직근무의 기준에 관한 국제협약)에 따르면 국제항해에 종사하는 항해사가 되기 위해서는 SMCP를 포함한 해사영어 대한 충분한 이해가 수반되어야 한다. 본 연구는 음성인식, 번역, 단어 기입 등 유형의 해사영어시험을 통하여 학생들 의 해사영어 활용 능력을 측정하고 플랫폼 사용에 따른 시험 점수 향상 정도, 나아가 초임항해사로 나가기 위하여 요구되는 해사영어 시험 플랫폼 활용 시간 등을 조사하고자 하였다. 실험은 먼저 초기 시험을 통해 학생들의 일반영어능력과 SMCP 활용 능력에 대한 연 관성을 조사한 후, 중간 시험 및 최종 시험을 통해 플랫폼 활용에 대한 점수 향상 정도, 응시시간 변화 등 요인을 측정하였다. 초기 시 험을 통해 개인 요인(예: 토익 점수, 본인 스스로에 대한 영어능력 평가)에 따른 그룹 간 해사영어시험 점수에 유의한 차이가 있음을 확인하였으며, 중간시험 및 최종시험을 통해 플랫폼 활용이 유의한 시험점수 향상으로 이어졌음을 확인하였다. 해당 연구는 해사 교육 분야에 다양하게 적용할 수 있는 학습 플랫폼 활용 효능을 조사하였으며 향후 해사영어 교육 외 그 범위를 넓혀 활용될 수 있을 것으 로 사료된다.
High-entropy alloys (HEAs) are attracting attention because of their excellent properties and functions; however, they are relatively expensive compared with commercial alloys. Therefore, various efforts have been made to reduce the cost of raw materials. In this study, MIM is attempted using coarse equiatomic CoCrFeMnNi HEA powders. The mixing ratio (powder:binder) for HEA feedstock preparation is explored using torque rheometer. The block-shaped green parts are fabricated through a metal injection molding process using feedstock. The thermal debinding conditions are explored by thermogravimetric analysis, and solvent and thermal debinding are performed. It is densified under various sintering conditions considering the melting point of the HEA. The final product, which contains a small amount of non-FCC phase, is manufactured at a sintering temperature of 1250oC.
Radioisotope ADME (RI-ADME) studies are enabling visualization of the biodistribution in molecular imaging. We applied RI-ADME to investigate the tumor targeting capacity and biodistribution of trastuzumab-monomethyl auristatin F (LCB14-0110) in JIMT-1 xenograft mice and healthy marmoset. The LCB14-0110 was labelled with 125I. 125I-LCB14-0110 was intravenously administered to the animals. The gamma-count and single-photon emission computed tomography/computed tomography (SPECT/CT) was conducted for biodistributioon and bioimaging of the biopharmaceutics. Tumor uptake in xenograft mice was highest at three-day after 125I-LCB14-0110 administration in both the biodistribution and SPECT/CT bioimaging. Alternatively, blood and organ tissues showed gradual decrease in radioactivity over time. In marmosets, radioactivity in all organ tissues rapidly reduced and no specific targeting of organs was observed in the biodistribution study and SPECT/CT imaging. Hence, 125ILCB14- 0110 demonstrated effective tumor targeting capacity and accumulated in JIMT-1 cell-bearing mice. However, accumulation did not occur in the organs of xenograft mice. Additionally, marmosets showed rapidly decrease in radioactivity throughout the entire body without accumulation in the normal organs. We also confirmed that the drug distribution was similar in normal organs between the two experimental animal species except spleen. Therefore, 125I is expected to be a useful tool in the study of RI-ADME in biopharmaceuticals through minimal antibody modification.
A simple, but effective means of tailoring the physical and chemical properties of carbon materials should be secured. In this sense, chemical doping by incorporating boron or nitrogen into carbon materials has been examined as a powerful tool which provides distinctive advantages over exohedral doping. In this paper, we review recent results pertaining methods by which to introduce boron atoms into the sp2 carbon lattice by means of high-temperature thermal diffusion, the properties induced by boron doping, and promising applications of this type of doping. We envisage that intrinsic boron doping will accelerate both scientific and industrial developments in the area of carbon science and technology in the future.
Control mating is important aspect in bee breeding programs. The technique of artificial insemination is the possible one that can surely control mating of the selected drones with the virgin queen. This is the first time applied artificial insemination technique to control mating of A. cerana in Korea. Altogether 18 queens were artificially inseminated, and 2,000 drones of Korean A. cerana were used to evaluate amount of semen collection. Semen of A. cerana is much difficult to separate from mucus in comparing with A. mellifera. The average amount of semen can be collected from one A. cerana drone was 0.09 μl, whereas the A. mellifera was more than 6 times (0.58 μl semen per A mellifera drone). Obtaining 1 μl of semen have to collect from 11.94 drones that successful semen ejection and have to kill 17 A. cerana drones. Queens artificially inseminated with 4 μl of semen (once insemination) or 8 μl of semen (twice insemination, each with 4 μl of semen) started laying egg later than naturally mated queens 5.3 and 2.5 days, respectively. The onsets of oviposition of artificially inseminated queens were 12.5 to 15.3 days. Queens received twice inseminations started laying eggs 2.8 days earlier than those received only once insemination. Artificially inseminated queens produced exclusively brood and were similar as the naturally mated ones. The brood production of the queens received once insemination with 4 μl of semen was insignificantly different than those received twice inseminations or naturally mated ones, suggesting that one artificial insemination with 4 μl of semen is favorable.
Due to their environmental and economical consequences, invasive species have become a major concern worldwide. Among them, the yellow-legged hornet, Vespa velutina, is a keen hunter of domestic honeybees. They use olfactory cues from the prey to assess food information. In this study, we investigated the attraction behavior of V. velutina to honeybee pheromone under outdoor conditions. Nine honeybee pheromones were tested and compared in order to find the best attractant. When testing specific compounds, the honeybee queen pheromone, homovanillyl alcohol, proved highly attractive.
Anthricin (Deoxypodophyllotoxin), a naturally occurring flavolignan, has well known anti-cancer properties in several cancer cells, such as prostate cancer, cervical carcinoma and pancreatic cancer. However, the effects of Anthricin are currently unknown in oral cancer. We examined the anticancer effect and mechanism of action of Anthricin in human FaDu hypopharyngeal squamous carcinoma cells. Our data showed that Anthricin inhibits cell viability in a dose- and time-dependent manner (IC50 50 nM) in the MTT assay and Live & Dead assay. In addition, Anthricin treated FaDu cells showed marked apoptosis by DAPI stain and FACS. Furthermore, Anthricin activates anti-apoptotic factors such as caspase-3, -9 and poly (ADP-ribose) polymerase (PARP), suggesting that caspase-mediated pathways are involved in Anthricin- induced apoptosis. Anthricin treatment also leads to accumulation of the pro-apoptotic factor Bax, followed by inhibition of cell growth. Taken together, these results indicate that Anthricn-induced cell death of human FaDu hypopharyngeal squamous carcinoma cells is mediated by mitochondrial-dependent apoptotic pathway. In summary, our findings provide a framework for further exploration on Anthricin as a novel chemotherapeutic drug for human oral cancer.