• 현장농수산연구지
• /
• 제25권4호
• /
• pp.67-77
• /
• 2024

This study analyzed the profitability and diagnosed business performance of fruit and vegetable (cherry tomatoes, tomatoes, strawberries, cucumbers) businesses targeting young farmers participating in the youth business incubation center of A Smart Farm Innovation Valley. The purpose of this is to provide basic data for decision-making by prospective young entrepreneurs. As a result of the analysis, Smart Farm Innovation Valley had the advantage of having a fixed rental fee. As a result, it was analyzed that various costs such as depreciation of large farm equipment, depreciation of farming facilities, repair and maintenance costs, land rent, floating capital service cost, fixed capital service cost, and land capital service cost are being reduced. However, excessive input of labor, water, electricity, other materials, and fertilizer costs was being made. Guidance to reduce these costs is expected to make a significant contribution to expanding the influx of young farmers.

• 한국분말재료학회지
• /
• 제23권2호
• /
• pp.149-169
• /
• 2016

Additive manufacturing (AM) is defined as the manufacture of three-dimensional tangible products by additively consolidating two-dimensional patterns layer by layer. In this review, we introduce four fundamental conceptual pillars that support AM technology: the bottom-up manufacturing factor, computer-aided manufacturing factor, distributed manufacturing factor, and eliminated manufacturing factor. All the conceptual factors work together; however, business strategy and technology optimization will vary according to the main factor that we emphasize. In parallel to the manufacturing paradigm shift toward mass personalization, manufacturing industrial ecology evolves to achieve competitiveness in economics of scope. AM technology is indeed a potent candidate manufacturing technology for satisfying volatile and customized markets. From the viewpoint of the innovation technology adoption cycle, various pros and cons of AM technology themselves prove that it is an innovative technology, in particular a disruptive innovation in manufacturing technology, as powder technology was when ingot metallurgy was dominant. Chasms related to the AM technology adoption cycle and efforts to cross the chasms are considered.

• 한국분말재료학회지
• /
• 제27권3호
• /
• pp.256-267
• /
• 2020

Metal additive manufacturing (AM) technologies are classified into two groups according to the consolidation mechanisms and densification degrees of the as-built parts. Densified parts are obtained via a single-step process such as powder bed fusion, directed energy deposition, and sheet lamination AM technologies. Conversely, green bodies are consolidated with the aid of binder phases in multi-step processes such as binder jetting and material extrusion AM. Green-body part shapes are sustained by binder phases, which are removed for the debinding process. Chemical and/or thermal debinding processes are usually devised to enhance debinding kinetics. The pathways to final densification of the green parts are sintering and/or molten metal infiltration. With respect to innovation types, the multi-step metal AM process allows conventional powder metallurgy manufacturing to be innovated continuously. Eliminating cost/time-consuming molds, enlarged 3D design freedom, and wide material selectivity create opportunities for the industrial adoption of multi-step AM technologies. In addition, knowledge of powders and powder metallurgy fuel advances of multi-step AM technologies. In the present study, multi-step AM technologies are briefly introduced from the viewpoint of the entire manufacturing lifecycle.

• 열처리공학회지
• /
• 제36권3호
• /
• pp.145-152
• /
• 2023

β titanium alloys containing β stabilizing elements such as V, Nb, Ta, Mo and Fe are widely used etc, due to their excellent specific strength, corrosion resistance, fatigue strength and easy formability. New metastable β titanium alloys are developed containing low-cost elements (Mo and Fe) in this study. Fe element is a strong β-stabilizer which can affect the mechanical and electrochemical properties of Ti-5Mo-xFe (x = 1, 4 wt%) alloys. These properties were analyzed in connection with microstructure and phase distribution. Ti-5Mo-4Fe alloy showed higher compression yield stress and maximum stress than Ti-5Mo-1Fe alloy due to solid-solution hardening and grain refinement hardening effect. As Fe element increased, Fe oxide formation and reduction of ${\bar{Bo}}$ (bond order) value affect the decrease of corrosion resistance. Ti-5Mo-xFe alloys were more excellent than Ti-6Al-4V ELI alloy.

• Corrosion Science and Technology
• /
• 제23권1호
• /
• pp.11-19
• /
• 2024

A Fe-Ni Bainitic steel as a weathering steel application was developed by combining its excellent mechanical properties and corrosion resistance in maritime environments. Nickel concentration (0.4-3 wt%) and inverted austempering multi-step (IAM) process were primary determinants of the microstructure of the Fe-Ni Bainitic steel. The initial austempering steel was performed at 300 ℃ for 600 seconds to obtain a partly bainitic transformation. The steel was heated again for 1800 s at 450 ℃. The microstructure was comprised of ferrite, a blocky martensite/austenite island, and a homogeneous lath-shape bainite structure with widths ranging from 4.67 to 6.89 ㎛. The maximum strength, 1480 MPa, was obtained with 3 wt% nickel. In this study, corrosion behavior was investigated utilizing potentiodynamic and electrochemical impedance spectroscopy (EIS) tests. A higher nickel content in Fe-Ni Bainitic steel refined the grain size, improved the bainite fraction, lowered the corrosion rate to 0.0257 mmpy, and increased the charge transfer of film resistance to 1369 Ω.

• 한국융합학회논문지
• /
• 제13권1호
• /
• pp.235-252
• /
• 2022

본 연구는 뿌리기업의 기술혁신 역량과 기술사업화 역량이 기업성과에 어떤 영향을 미치는지와 금속 중심 공정기술 분야와 신소재·플랫폼 공정기술 분야의 두 집단 간에 기업성과의 차이가 있는지를 실증적으로 규명하였다. 표본은 국가뿌리산업진흥센터 등의 자료를 이용하여 설문지 플랫폼을 통한 온라인 조사를 진행하였다. 분석 방법은 기초통계분석, 상관관계분석, 두 집단 간 평균 차이 분석, 다중회귀분석을 실시하였다. 연구 분석 결과, 첫째, 금속중심 공정기술 분야보다 신소재 플랫폼 공정기술 분야가 기업성과 평균이 높은 것으로 나타났다. 둘째, 기술혁신 체제, 기술축적 역량, 마케팅 역량, 생산화 역량이 비재무적 성과에 통계적으로 유의한 것으로 분석되었고, 연구개발 역량, 기술축적 역량, 제품화 역량, 마케팅 역량이 재무적 성과에 통계적으로 유의한 영향을 미치는 것으로 분석되었다. 공정기술 플랫폼 분야가 비재무적 성과에 통계적으로 유의한 영향을 미치는 것으로 분석되었다.

• Journal of Electrochemical Science and Technology
• /
• 제14권4호
• /
• pp.361-368
• /
• 2023

In lithium-sulfur (Li-S) batteries, encapsulation of sulfur in activated carbon (AC) materials is a promising strategy for preventing the dissolution of lithium polysulfide into electrolytes and enhancing cycle life, because instead of solid-liquid-solid reactions, quasi-solid-state (QSS) reactions occur in the AC micropores. While a high weight fraction of sulfur in S/AC composites is essential for achieving a high energy density of Li-S cells, the deterioration mechanisms under such conditions are still unclear. In this study, we report the deterioration mechanisms during charge-discharge cycling when the discharge products overflow from the AC. Analysis using scanning electron microscopy and energy-dispersive X-ray spectrometry confirms that the sulfur in the S/AC composites migrates outside the AC as cycling progresses, and it is barely present in the AC after 20 cycles, which corresponds to the capacity decay of the cell. Impedance analysis clearly shows that the electrical resistance of the S/AC composite and the charge-transfer resistance of QSS reactions significantly increase as a result of sulfur migration. On the other hand, the charge-discharge cycling performance under limited-capacity conditions, where the discharge products are encapsulated inside the AC, is extremely stable. These results reveal the degradation mechanism of a Li-S cell with micro-porous carbon and provide crucial insights into the design of a S/AC composite cathode and its operating conditions needed to achieve stable cycling performance.

• Korean Journal of Radiology
• /
• 제21권5호
• /
• pp.550-560
• /
• 2020

Objective: To evaluate the interobserver agreement, diagnostic value, and associated clinical factors of automated breast ultrasound (ABUS) coronal features in differentiating breast lesions. Materials and Methods: This study enrolled 457 pathologically confirmed lesions in 387 female (age, 46.4 ± 10.3 years), including 377 masses and 80 non-mass lesions (NMLs). The unique coronal features, including retraction phenomenon, hyper- or hypoechoic rim (continuous or discontinuous), skipping sign, and white wall sign, were defined and recorded. The interobserver agreement on image type and coronal features was evaluated. Furthermore, clinical factors, including the lesion size, distance to the nipple or skin, palpability, and the histological grade were analyzed. Results: Among the 457 lesions, 296 were malignant and 161 were benign. The overall interobserver agreement for image type and all coronal features was moderate to good. For masses, the retraction phenomenon was significantly associated with malignancies (p < 0.001) and more frequently presented in small and superficial invasive carcinomas with a low histological grade (p = 0.027, 0.002, and < 0.001, respectively). Furthermore, continuous hyper- or hypoechoic rims were predictive of benign masses (p < 0.001), whereas discontinuous rims were predictive of malignancies (p < 0.001). A hyperechoic rim was more commonly detected in masses more distant from the nipple (p = 0.027), and a hypoechoic rim was more frequently found in large superficial masses (p < 0.001 for both). For NMLs, the skipping sign was a predictor of malignancies (p = 0.040). Conclusion: The coronal plane of ABUS may provide useful diagnostic value for breast lesions.

• Journal of Microbiology and Biotechnology
• /
• 제21권1호
• /
• pp.28-36
• /
• 2011

Diblock copolymers composed of poly(${\varepsilon}$-caprolactone) (PCL) and poly(N,N-dimethylamino-2-ethyl methacrylate) (PDMAEMA), or methoxy polyethylene glycol(PEG), were synthesized via a combination of ring-opening polymerization and atom-transfer radical polymerization in order to prepare polymeric nanoparticles as an antifungal drug carrier. Amphotericin B (AmB), a natural antibiotic, was incorporated into the polymeric nanoparticles. The physical properties of AmB-incorporated polymeric nanoparticles with PCL-b-PDMAEMA and PCL-b-PEG were studied in relation to morphology and particle size. In the aggregation state study, AmB-incorporated PCL-b- PDMAEMA nanoparticles exhibited a monomeric state pattern of free AmB, whereas AmB-incorporated PCL-b- PEG nanoparticles displayed an aggregated pattern. In in vitro hemolysis tests with human red blood cells, AmBincorporated PCL-b-PDMAEMA nanoparticles were seen to be 10 times less cytotoxic than free AmB (5 ${\mu}g$/ml). In addition, an improved antifungal activity of AmBincorporated polymeric nanoparticles was observed through antifungal activity tests using Candida albicans, whereas polymeric nanoparticles themselves were seen not to affect activity. Finally, in vitro AmB release studies were conducted, proving the potential of AmB-incorporated PCL-b-PDMAEMA nanoparticles as a new formulation candidate for AmB.

• 기술혁신학회지
• /
• 제10권3호
• /
• pp.431-457
• /
• 2007

본 연구는 부품소재 중핵기업의 기술혁신 결정요인을 분석하기 위해 기업규모, 시장집중도 그리고 기업의 특성을 나타내는 일반변수들과 혁신유무의 관계를 측정하였다. 본 연구는 이를 위하여 과학기술정책연구원이 조사한 '기술혁신조사' (KIS2005)의 원자료와 Probit 모형을 활용하였다. 실증분석 결과에 의하면 기업규모는 혁신의 유무와 정(+)의 관계에 있으나 시장집중도는 부(-)의 영향을 미치는 것으로 나타났다. 기업특성을 나타내는 일반변수 중에는 순이익과 연구개발비가 혁신유무와 정(+)의 관계를 갖는 반면, 수출액과 자기자본비율은 부(-)의 관계에 있는 것으로 나타났다. 결론적으로, 부품소재 중핵기업의 기술혁신 활동을 촉진하기 위해서는 기업규모의 증대와 경쟁적인 시장구조의 조성이 이루어져야 할 것이며 또한 연구개발 활동에 대한 재정적 지원과 함께 자본 및 금융시장에서의 원활한 자본조달이 뒷받침되어야 할 것이다. 다만, 본 연구의 실증분석에서 나타난 수출액과 혁신유무의 관계에 대해서는 추가적인 연구가 필요할 것이다.