• Journal of the Korean Wood Science and Technology
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• 제49권4호
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• pp.287-298
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• 2021

Torch ginger (Etlingera elatior Jack) is a potential source of lignocellulose material for various derivative products. This study aims to determine the chemical components, ratio of syringyl to guaiacyl units (S/G) in lignin, and crystallinity of the biomass of torch ginger. The effects of soda pulping on the chemical characteristics of torch ginger pulp were also studied. Pulping of the chips was conducted with active alkali of 15%, 20%, and 25% and a Liquor-to-Wood (L/W) ratio of 4:1, 5:1, and 6:1. The impregnation and pulping times at maximum temperature (170℃) were 120 and 90 min, respectively. To assess the effect of treatments on the properties of pulping, a two-factorial experimental design was applied. Results showed that the content of α-cellulose and hemicellulose in the torch ginger was 48.48% and 31.50%, respectively, with an S/G ratio of 0.70 in lignin. Soda pulping changed the crystalline structure of the biomass from triclinic to monoclinic. Active alkali, L/W ratio, and interactions considerably influenced the observed responses. The degree of delignification increased with an increase in the loading of active alkali, which lead to a decrease in the kappa number of the pulp. An active alkali content of 25% and an L/W ratio of 6:1 resulted in the highest delignification selectivity with a kappa number of 2.78 and a yield of 24%. Given its cellulose content and ease of pulping, torch ginger can be a potential raw material for derivative products that require delignification as pretreatment. However, the increase in cellulose crystallinity should be considered when converting torch ginger to bioethanol.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.136.2-136.2
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• 2015

반도체 제조는 chip의 성능 향상 및 단가 하락을 위해 지속적으로 pattern size가 nano size로 감소해 왔고, capacitor 용량은 증가해 왔다. 이러한 현상은 contact hole의 aspect ratio를 지속적으로 증가시킨바, 그에 따라 최적의 HARC (high aspect ratio contact)을 확보하는 적합한 dry etch process가 필수적이다. 그러나 HARC dry etch process는 많은 critical plasma properties 에 의존하는 매우 복잡한 공정이다. 따라서, critical plasma properties를 적절히 조절하여 higher aspect ratio, higher etch selectivity, tighter critical dimension control, lower P2ID과 같은 plasma characteristics을 확보하는 것이 요구된다. 현재 critical plasma properties를 제어하기 위해 다양한 plasma etching 방법이 연구 되어왔다. 이 중 plasma를 낮은 kHz의 frequency에서 on/off 하는 pulsed plasma etching technique은 nanoscale semiconductor material의 etch 특성을 효과적으로 향상 시킬 수 있다. 따라서 본 실험에서는 dual-frequency capacitive coupled plasma (DF-CCP)을 사용하여 plasma operation 동안 duty ratio와 pulse frequency와 같은 pulse parameters를 적용하여 plasma의 특성을 각각 제어함으로써 etch selectivity와 uniformity를 향상 시키고자 하였다. Selective SiO2 contact etching을 위해 top electrode에는 60 MHz pulsed RF source power를, bottom electrode에는 2MHz pulse plasma를 인가하여 synchronously pulsed dual-frequency capacitive coupled plasma (DF-CCP)에서의 plasma 특성과 dual pulsed plasma의 sync. pulsing duty ratio의 영향에 따른 etching 특성 등을 연구 진행하였다. 또한 emissive probe를 통해 전자온도, OES를 통한 radical 분석으로 critical Plasma properties를 분석하였고 SEM을 통한 etch 특성분석과 XPS를 통한 표면분석도 함께 진행하였다. 그 결과 60%의 source duty percentage와 50%의 bias duty percentage에서 가장 향상된 etch 특성을 얻을 수 있었다.

• 센서학회지
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• 제28권4호
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• pp.256-261
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• 2019

In this study, mid-infrared transparent zinc sulfide (ZnS) ceramics were fabricated through hydrothermal synthesis with different molar ratios of S/Zn (S/Zn = 0.8, 1.0, 1.2, 1.4, and 1.6). The ZnS ceramics were sintered at a relatively low temperature of $850^{\circ}C$ to prevent the occurrence of the hexagonal phase featuring optical anisotropy. The phase composition, microstructure, and optical properties of the ZnS ceramics were subsequently investigated by employing X-ray diffraction, scanning electron microscopy, and Fouriertransform infrared spectroscopy. The results obtained indicate that the ZnS nanoparticles feature the cubic phase, without the hexagonal phase. Moreover, with increasing S, the crystallinity and particle size of the ZnS nanoparticles increased. The crystallinity and density of the ZnS ceramics improved when the molar ratio of S was higher than the molar ratio of Zn, thereby enhancing the transmittance. Furthermore, the ZnS ceramic with an S/Zn value of 1.2 was found to exhibit the highest transmittance of approximately 69% owing to the reduced occurrence of the hexagonal phase and a high density of 99.8%.

• 동력기계공학회지
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• 제5권2호
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• pp.50-56
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• 2001

In this study, the effect of specimen thickness and stress ratio on fatigue crack growth in S45C steel was investigated. Acoustic emission was monitored during the fatigue crack growth test. Both crack closure and AE technique were used in assessing fatigue crack growth behavior. Constant amplitude loading tests were performed on CT type specimen with three different thicknesses and stress ratios. Crack closure was investigated to explain the influence of specimen thickness and stress ratio on the fatigue crack growth in the second growth region. The crack closure effect was decreased with specimen thickness and stress ratio.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.749-752
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• 2006

Autoclaved lightweight concrete (ALC) have high water absorption, low compressive strength and popout the origin of the low surface strength in its properties. These properties make troubles under construction such as cracking and popout. Thus, this study is to improve the fundamental strength by control of $SO_3$ ratio's and Sand Sulrry grain size. From the test result, Improved ALC have a good fundamental properties. Compressive strength, and abrasion's ratio were improved depending on increasing $SO_3$ ratio's and Sand Sulrry grain size control.

• 국제초고층학회논문집
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• 제12권3호
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• pp.195-201
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• 2023

This paper reviews the history of the birth and development of the skyscraper in Japan, mainly from the perspective of the legal system, and presents the following points: 1) After 1919, building height was limited to 31 m or less, which continued after the war and defined the skyline of Japan's major cities; 2) The 31-meter height limit became a problem during rapid economic growth. With the development of tall building construction technology, the height limit was eliminated, and skyscrapers were born in Japan in the 1960s; 3) Later, the number of skyscrapers increased more rapidly in the post-bubble period after the collapse of the bubble economy in the 2000s than in the boom years of the 1980s, when the floor-area ratio was relaxed for economic uplift and urban renewal. The number of skyscrapers increased rapidly against the backdrop of the deregulation of the floor-area ratio.

• 전기학회논문지P
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• 제59권3호
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• pp.330-334
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• 2010

We tried to combine a transformer with a superconducting element and investigated the current limiting characteristics. When a superconducting element was connected to third winding of the transformer, the fault current was limited to about 90 % effectively. The fault current and consumption power were able to be controlled by the turn's ratio of secondary and third windings. It gives flexibility of the rating of a transformer in the power grid. As a result, power burden of a superconducting element was reduced by the decrease of turn's ratio in third winding of a transformer. It was because the voltage behavior of a superconducting element was dependent on turn's ratio of a transformer while the current characteristic was independent.

• The Journal of Asian Finance, Economics and Business
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• 제8권5호
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• pp.109-115
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• 2021

This study aims to examine the effect of Operating Costs and Income, Loan to Deposit Ratio on the Return on Asset (ROA) of Public-Private Foreign Exchange Banks listed on the Indonesia Stock Exchange (IDX) during the 2015-2018 period. This study is a quantitative study using financial reports of Public-Private Foreign Exchange Banks listed on the IDX as a data source. This study's population is 25 Public-Private Foreign Exchange Banks listed on the IDX. This study uses purposive sampling to determine the sample to produce 21 banking companies. Data was analyzed using multiple linear regression methods and descriptive statistics. The F Test calculation results state that all the variables of free operating expenses, operating income, and the loan to deposit ratio simultaneously and significantly affect the return on assets (ROA) variable in Public-Private Foreign Exchange Banks listed on the IDX. This study's results indicate that simultaneously Operational Costs, Operational Income, and Loan to Deposit Ratio have a significant effect on ROA. Operational Costs and Operational Income have a significant negative impact on Return on Assets. The third hypothesis shows that the Loan to Deposit Ratio has a positive and insignificant effect on Return on Assets.

• 한국식품영양학회지
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• 제26권3호
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• pp.515-525
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• 2013

This study was performed to investigate the characteristics of nutrient intake according to metabolic syndrome in Korean elderly. Data on 1,200 elderly (men 545, women 655) over 65 years was obtained from the Korea National Health and Nutrition Examination Survey 2010. The subjects were divided into metabolic syndrome (MetS) and normal groups based on NCEP-ATP III guidelines and by applying the Asia-Pacific definition with waist circumference. The prevalence of MetS was 48.9% in all subjects, 35.6% in men and 58.9% in women, respectively. All nutrient intake was significantly lower in MetS than normal subjects, except iron, vitamin A, carotene, and retinol. In the carbohydrate: protein: fat (C:P:F) ratio, MetS showed a higher rate for carbohydrate, but a lower rate for protein and fat than normal. MetS was lower in calcium, vitamin B1, and vitamin C by the nutrient adequacy ratio than normal. Mean adequacy ratio of MetS (0.69) was lower than that of the normal group (0.72). These results demonstrated that undernutrition, not excess intake of specific nutrients - energy, fat, or cholesterol was associated with the risk for MetS in Korean elderly with MetS. Therefore, it is recommended to have a healthy dietary pattern with diverse nutrients for the prevention of MetS.

• 한국산학기술학회논문지
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• 제18권2호
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• pp.625-630
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• 2017

본 연구는 우리나라 은행의 중소기업대출과 자기자본비율 및 경영성과의 관계를 분석하였다. 또한 은행 중소기업대출과 자기자본비율 및 경영성과의 관계가 금융위기를 전후하여 유의적인 차이가 존재하는지를 분석하였다. 연구 결과에 따르면 우리나라의 은행 중소기업대출은 은행 자기자본비율과 경영성과에 유의적 영향을 주는 것으로 나타났다. 자기자본비율의 분석에서는 모든 분석 결과에서 유의한 결과를 보인 반면, 경영성과 분석에서는 일부 경영성과 지표에서 유의한 결과를 보였다. 또한 은행 중소기업대출과 자기자본비율 및 경영성과의 관계는 금융위기 전후에 걸쳐 유의한 차이를 보이는 것으로 나타났다. 자기자본비율 분석에서는 모든 분석결과에서 유의한 결과를 보인 반면, 경영성과 분석에서는 일부 지표에서 유의한 결과를 보였다. 금융위기 이후 은행 중소기업 대출이 은행 자기자본비율 및 경영성과 개선에 유의한 영향을 미치는 것으로 나타났다. 금융위기 이전에는 중소기업 대출이 기본 자기자본비율에 부정적 영향을 미치는 반면, 중소기업 대출이 BIS자기자본비율 및 경영성과에 미치는 유의한 영향은 발견되지 않았다. 그러나 금융위기 이후에는 중소기업 대출이 기본 자기자본비율 뿐 아니라 BIS 자기자본비율 및 경영성과의 개선에 유의한 영향을 미치는 것으로 나타났다. 금융위기를 전후하여 우리나라 은행의 중소기업 대출이 은행 자기자본비율 및 경영성과 개선에 미치는 영향에 유의적 변화가 있는 것으로 진단된다. 본 연구는 은행의 기업의 자금중개기능 측면 및 은행 대출자산 구성 측면에서 중요성을 가지는 은행 중소기업대출을 중심으로 은행 자기자본비율과 경영성과의 관계를 미시적 관점에서 분석하였다는 점에서 의의가 있다. 본 연구는 은행의 중소기업대출 행태 결정요인, 중소기업대출 기법 중심이 주류를 이루고 있는 기존 은행 중소기업대출 연구에 새로운 결과를 제시할 것으로 기대된다. 금융위기를 전후하여 우리나라 은행의 중소기업 대출이 은행 자기자본비율 및 경영성과 개선에 미치는 영향이 변화가 있다는 본 연구결과는 은행의 중소기업 대출관계 변화 및 중소기업 금융 활성화 등에 유의미한 시사점을 줄 것으로 기대된다.