• Journal of Biosystems Engineering
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• 제23권6호
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• pp.561-570
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• 1998

The MLR(Multiple Linear Regression) models to estimate soluble solids content non-destructively were presented to make a selection of optimal photosensor utilized to measure the soluble solids content of apples. Visible and NIR absorbance in the 400 to 2498 nanometer(nm) wavelength region, soluble solids content(sugar content), hardness, and weight were measured for 400 apples(gala). Spectrophotometer with fiber optic probe was utilized for spectrum measurement and digital refractometer was used for soluble solids content. Correlation between absorbance spectrum and soluble solids content was analyzed to pick out the optimal wavelengths and to develop corresponding prediction model by means of MLR. For the coefficient of determination($R^2$) to be over 0.92, the MLR models out of the original absorbance were built based on 7 wavelengths of 992, 904, 1096, 1032, 880, 824, 1048nm, and the ones of the second derivative absorbance based on 5 wavelengths of 784, 1056, 992, 808, 872nm. The best model of the second derivative absorbance spectrum had $R^2$=0.91, bias= -0.02bx, SEP=0.28bx for unknown samples.

• 소성∙가공
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• 제22권6호
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• pp.334-339
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• 2013

Direct Laser Melting is a prototyping process whereby a 3-D part is built layer wise by melting the metal powder with laser scanning. This process is strongly influenced by the shielding gas and the laser operating parameters such as laser power, scan rate, layering thickness, and rescanning. The shielding gas is especially important in affecting the microstructure and mechanical properties. In the current study, fabrication experiments were conducted in order to analyze the effect of shielding gas on the forming characteristics of direct laser melting. Cylindrical parts were produced from a Fe-Ni-Cr powder with a 200W fiber laser. Surface quality, porosity and hardness as a function of the layering thickness and shield gas were evaluated. By decreasing the layering thickness, the surface quality improved and porosity decreased. The selection of which shield gas, Ar or $N_2$, to obtain better surface quality, lower porosity, and higher hardness was examined. The formability and mechanical properties with a $N_2$ atmosphere are better than those parts formed under an Ar atmosphere.

• 한국농공학회논문집
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• 제58권2호
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• pp.73-82
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• 2016

This study is about development of personal disaster shelters for minimization of the casualties caused by the landslide and steep slope collapse. The objectives of present research is the selection of disaster evacuation facilities utilizing FRP (Fiber Reinforced Plastic) material. For the proper assessment of FRP member, several layers by strength test and the three-dimensional numerical analysis of these FRR member was carried out. As a result, the personal disaster evacuation facility utilizing FRP materials, was found to be of a material that is able to protect the weak person at the time of the collapse of the landslides and steep slopes.

• 대한후두음성언어의학회지
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• 제32권3호
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• pp.118-123
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• 2021

The pulsed photoangiolytic 532-nm potassium-titanyl-phosphate (KTP) laser has emerged in recent years as an efficacious treatment modality for vocal fold lesions. It also has broadened the indications for other laryngeal laser surgery. Features of KTP laser that it is a fiber-based delivery system and its energy is selectively absorbed by oxyhemoglobin make it suitable for office-based laryngeal procedures. An office-based KTP laser surgery provides an alternative management option for benign laryngeal diseases and can be performed comfortably under flexible endoscopic guidance which is placed through the nose of a fully awake patient. Office-based laryngeal surgery with a KTP laser can alleviate the need for general anesthesia. However, there are some limitations to apply due to reduced visual precision and the fact that the vocal folds are moving during procedures. Clinicians should carefully weigh the advantages and disadvantages of office-based procedures before a treatment option is selected. Patient selection and standardized laser energy parameters may help in decreasing complications and improving the treatment results.

• 한국의상디자인학회지
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• 제24권1호
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• pp.35-43
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• 2022

This study aims to analyze the physical properties of non-woven fabric sheets, which continue to grow in the cosmetic market. Non-woven fabric sheets were used as specimens, and a total of 17 samples were analyzed. To evaluate the physical properties of the non-woven fabric sheet, the weight, tensile strength, surface properties, free swell absorption, and wet stiffness were tested. Through the results itw was determined that non-woven fabric sheets for mask packs should be manufactured considering fiber arrangement so that the weight is 40 g/m², and the tensile strength should be maintained near 12 kgf. In addition, it was confirmed that the material selection and process conditions should be adjusted so that the free swell absorption is at least 8 g/g, and the wet stiffness is 200 mg. Therefore, since the non-woven fabrics for the mask sheets can be used in various products depending on fabric composition, this study will be expected to be basic data for the continuous growth of the sheet-type mask packs coming to market.

• Nuclear Engineering and Technology
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• 제54권3호
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• pp.926-939
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• 2022

The area of this study will cover the location-wise seismic response variation of an electrical cabinet in nuclear power point (NPP) based on classical reliability analysis. The location-based seismic ground motion (GM) selection is carried out with the help of probabilistic seismic hazard analysis using PSHRisktool, where the variation of reliability analysis can be understood from the relation between the reliability index and intensity measure. Two different approaches such as the first-order second moment method (FOSM) and Monte Carlo Simulation (MCS) are helped to evaluate and compare the reliability assessment of the cabinet. The cabinet is modeled with material uncertainty utilizing Steel01 as the material model and the fiber section modeling approach is considered to characterize the section's nonlinear reaction behavior. To verify the modal frequency, this study compares the FEM result with recorded data using Least-Squares Complex Exponential (LSCE) method from the impact hammer test. In spite of a few investigations, the main novelty of this study is to introduce the reader to check and compare the seismic reliability assessment variation in different seismic locations and for different earthquake levels. Alongside, the betterment can be found by comparing the result between two considered reliability estimation methods.

• 한국기계가공학회지
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• 제21권2호
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• pp.137-143
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• 2022

Composite materials, being light-weight and of high mechanical strength, are increasingly used in various industries such as the aerospace, automobile, sporting-goods manufacturing, and ship-building industries. Recently, manufacturing of composite materials using 3D printers has increased. 3D-printed composite materials are made in free-form and adapted for end-use by adjusting the fiber content and orientation. However, research on the machining of 3D printed composite materials is limited. The aim of this study is to develop a machine learning method to select machining conditions for machining of 3D-printed composite materials. The composite material was composed of Onyx and carbon fibers and stacked sequentially. The experiments were performed using the following machining conditions: spindle speed, feed rate, depth of cut, and machining direction. Cutting forces of the different machining conditions were measured by milling the composite materials. PCA, a method of machine learning, was developed to select the machining conditions and will be used in subsequent experiments under various machining conditions.

• 한국산업융합학회 논문집
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• 제25권4_2호
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• pp.673-686
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• 2022

Recently, as the importance of eco-friendly energy has increased hydrogen gas is in the spotlight as future energy. Due to its special properties, hydrogen gas is more difficult to detect requiring more precise sensing technology. The primary objective of this study is to design a concept of an underground hydrogen pipeline monitoring system. For this, the following research works are conducted sequentially; 1)selection of core technology for conceptual design, 2)state-of-the-art review, 3)design of a concept of the system. As a result, DAS(Distributed Acoustic Sensing), and DTS(Distributed Temperature Sensing) are selected as each core technology. Furthermore, a conceptual design of an underground hydrogen pipeline monitoring system is deducted. It is expected that the impact on the eco-friendly energy industry will be enormous due to the increasing interest in using hydrogen energy.

• Advances in concrete construction
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• 제13권 2호
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• pp.153-162
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• 2022

Prefabricated exterior wall panel is the main non-load-bearing component of assembly building, which affects the comprehensive performance of thermal insulation and durability of the building. It is of great significance to develop new prefabricated exterior wall panel with durable and lightweight characteristics for the development of energy-saving and assembly building. In the prefabricated sandwich insulation hanging wall panel, the selection of material for the outer layer and the arrangement of the connector of the inner and outer wall layers affect the mechanical performance and durability of the wall panels. In this paper, high performance cement-based composites (HPFRC) are used in the outer layer of the new type wall panel. FRP bars are used as the interface connector. Through experiments and analysis, the influence of the arrangement of connectors on the mechanical behaviors of thin-walled composite wall panel and the panel with window openings under two working conditions are investigated. The failure modes and the role of connectors of thin-walled composite wallboard are analyzed. The influence of the thickness of the wall layer and their combination on the strain growth of the control section, the initial crack resistance, the ultimate bearing capacity and the deformation of the wall panels are analyzed. The research work provides a technical reference for the engineering design of the light-weight thin-walled and durable composite sandwich wall panel.

• 한국초지조사료학회지
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• 제23권4호
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• pp.299-306
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• 2003

사료용으로 적합한 우량품종을 선발하기 위하여 콩의 18개 장려품종을 5월 11일에 30x 20cm 거리로 파종하여 생육$.$수량성 및 조성분 등을 조사한 결과를 하면 다음과 같다. 개화까지의 일수는 석량콩, 큰올콩 및 화엄콩이 58일로 짧은 편이었고, 단파흑두는 93일로 가장 늦었다. 그외 다른 품종이 개화까지 일수는 65∼69일이었다. 경장은 푸른콩, 남해콩이 각각 129.3, 124.6cm로 가장 길었고 큰올콩, 화엄콩 및 석량콩은 63.9∼66.9cm로 짧은 편이었다. 주당 분지수는 소백콩, 만리콩, 풍산콩, 광안콩 및 금강콩이 많았으며, 엽수는 소백콩, 익산콩, 남해콩이 많았고, 경직경은 푸른콩과 장미콩이 굵은 편이었다. 생초수량은 익산콩, 소백콩, 남해콩이 각각 39.5, 39.3, 38.0MT/ha로 가장 많았고, 건물수량은 백운콩, 푸른콩, 단파흑두가 각각 7.7, 7.5, 7.4MT/ha으로 가장 많았다. TDN 수량이 높은 품종은 백운콩, 단파흑두, 남해콩이며 조단백질수량이 높은 품종은 백운콩, 푸른콩, 남해콩이었다. 조단백질 함량은 단원콩, 다원콩, 석량콩과 풍산콩이 21.1∼22.5%로 높았고, 조섬유 함량이 높은 품종은 두유콩, 광안콩이며 조지방함량은 장미콩과 큰올콩이 2.97%로 비교적 높은 편이었다. 조회분 함량은 소백콩과 광안콩 품종이 10.0% 내외로 높았다. 가용성무질소물은 남해콩, 석량콩, 큰올콩과 진품콩이 40.0∼43.5%로 높았으며 가소화양분 총량은 큰올콩, 단파흑두, 남해콩과 석량콩이 59.8∼60.9%로 비교적 높은 품종이었다. 제주지역에서 청예용으로 콩을 재배하고자 할 경우, 영양과 수량면을 복합적으로 고려한다면 단백질 함량이 19% 이상이고 TDN 수량이 ha당 4.20톤 이상이면서 건초수량 7.0톤, 생초수량이 36.0톤 이상으로 높은 영양가를 보유하면서 수량성이 우수했던 남해콩, 단파흑두와 백운콩 품종이 가장 적합할 것으로 판단된다.