• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 춘계학술대회 논문집
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• pp.35-38
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• 2004

In general, tube drawing process is composed of two steps, so called first drawing and second drawing. Drawing cracks are mainly occurred during the 2nd drawing process due to the improper drawing process. In order to analyze the reduction distribution in successive two-step drawing process, tube drawing process was simulated by finite element method. From the finite element analysis, the balance between first and second reduction is proved to be important factor to prevent drawing cracks. Hence the numerical expression was developed for tube drawing process to distribute even strain and criteria curves that can predict the safe drawing region were also proposed using this numerical formula.

• 한국의류학회지
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• 제19권3호
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• pp.434-447
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• 1995

This research was intended to identify variables influencing on risk perception and risk reduction behavior in clothing purchase situations. Responses from 631 female adults living in Seoul area were collected and analyzed. Towner for social occasions or working in office was used as clothing stimulus. The analysis included three product variables(price, style, type of clothing), 4 personality variables(generalized self-confidence, specific self-confidence, generalized informativeness, fashion informativeness), 2 clothing attitude variables(clothing importance, clothing interest), 4 demographic variables(age, educational level, occupation, income), and 3 situational variables(purchase planning, time pressure, effects of shopping company). Multiple regression revealed the fact that each type of clothing risk and each type of risk reduction behavior was influenced by the set of different variables. Generalized self- confidence and age and time pressure had more effects on clothing risk perception, while clothing risk reduction behavior was more influenced by clothing risk type, clothing interest, price of clothing and fashion informativeness. Implications for marketing strategies planning were also provided.

• 소성∙가공
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• 제13권8호
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• pp.671-677
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• 2004

For the large reduction in tube cross section, the tube drawing process is usually performed by two successive passes, so called first drawing and second drawing. In multi-pass drawing process, the reduction balance is important to prevent drawing cracks. Therefore in this study, the model for uniform reduction distribution in two-pass drawing process has been developed on the basis of cross sectional variation of drawn tube. For the given product geometry the model provides optimal diameter and thickness that can evenly distribute drawing reductions. The capability of model is well confirmed by finite element analysis of tube drawing process. Criteria curves at various limit strains to determine whether the drawn tube would fail during drawing process are also proposed by using newly developed model.

• Carbon letters
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• 제9권1호
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• pp.23-27
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• 2008

The adsorption and reduction of Cr (VI) to Cr (III) by surface modified activated carbon (AC) in an aqueous solution was studied. The effects of surface modifications on the properties of the carbons were investigated by the analysis of specific surface area, carbon surface pH, acid/base surface values and functional groups. In order to understand the Cr(VI) adsorption and reduction ratio from Cr(VI) to Cr(III), the Cr adsorption capacity of AC was also measured and discussed by using inductively coupled plasma and UV spectrophotometer. The modifications bring about substantial variation in the chemical properties whereas the physical properties such as specific surface area, pore volume and pore size distribution nearly were not changed. Total Cr adsorption efficiency of as-received activated carbon (R-AC) and nitric acid treated activated carbon (N1-AC and N2-AC) were recorded on 98.2, 99.7 and 100%. Cr(III) reduction efficiency of R-AC increased largely from 0.4% to 28.3% compared to N1-AC and N2-AC.

• 센서학회지
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• 제31권5호
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• pp.343-347
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• 2022

Recently, the problem of global warming caused by greenhouse gases is getting serious due to the development of industry and the increase in transportation means. Accordingly, the need for a technology to reduce carbon dioxide, which accounts for most of the greenhouse gas, is increasing. Among them, a catalyst for converting carbon dioxide into fuel is being actively studied. Catalysts for reducing carbon dioxide are classified into thermal catalysts and photocatalysts. In particular, the photocatalyst has the advantage that carbon dioxide can be reduced only by irradiating ultraviolet rays at room temperature without high temperature or additional gas. TiO₂ is widely used as a photocatalyst because it is non-toxic and has high stability, but has a disadvantage of low carbon dioxide reduction efficiency. To increase the reduction efficiency, 1-propanol was used in the synthesis process. This prevents agglomeration of the catalyst and increases the specific surface area and pores of TiO₂, thereby increasing the surface area in contact with carbon dioxide. As a result of measuring the CO₂ reduction efficiency, it was confirmed that the efficiency of TiO₂ with 1-propanol and TiO₂ without 1-propanol was 19% and 12.3%, respectively, and the former showed a 1.5 times improved efficiency.

• Corrosion Science and Technology
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• 제14권4호
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• pp.190-194
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• 2015

The splash zone is the most corrosive area of the marine environment, and the corrosion of steel structures exposed in this area is a serious concern. DH36 steel is one of most commonly used steels for offshore oil platforms in China, and its corrosion behaviour in splash zones was studied in this paper. Polarization curves were obtained from the corroded steel exposed in this area while the morphologies and rusts of the rust steel were characterized using scanning electron microscopy and X-ray diffraction. Double rust layers were formed in the splash zone. The inner layer contained magnetite and fine flaky lepidocrocite, and the outer layer was composed of accumulated flaky lepidocrocite and a small amount of goethite. In the wet period, the iron dissolved and reacted with lepidocrocite, and magnetite appeared, while the magnetite was oxidized to lepidocrocite again during the dry period. Electrochemical reduction and chemical oxidization cycled in intermittent wetting and drying periods, and magnetite and lepidocrocite were involved in the reduction reaction, leading to serious corrosion.

• Asian Pacific Journal of Cancer Prevention
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• 제17권2호
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• pp.785-789
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• 2016

A key drug for treatment of EGFR mutation-positive non-small cell lung cancer is epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI). While the dosage of many general anti-tumor drugs is adjusted according to the patient body surface area, one uniform dose of most TKIs is recommended regardless of body size. In many cases, dose reduction or drug cessation is necessary due to adverse effects. Disease control, however, is frequently still effective, even after dose reduction. In this study, we retrospectively reviewed the characteristics of 26 patients at Fukuoka University Hospital between January 2004 and January 2015 in whom the EGFR-TKI dose was reduced with respect to progression free survival and overall survival. There were 10 and 16 patients in the gefitinib group and the erlotinib group, respectively. The median progression-free survival in the gefitinib group and the erlotinib group was 22.4 months and 14.1 months, respectively, and the median overall survival was 30.5 months and 32.4 months, respectively. After stratification of patients by body surface area, the overall median progression-free survival was significantly more prolonged in the low body surface area (<1.45 m2) group (25.6 months) compared to the high body surface area (>1.45 m2) group (9.7 months) (p=0.0131). These results indicate that low-dose EGFR-TKI may sufficiently control disease without side effects in lung cancer patients with a small body size.

• 한국수자원학회논문집
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• 제56권12호
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• pp.905-918
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• 2023

본 연구에서는 목감천 유역에서 투수성포장(PP)과 빗물저류조(RB)의 설치에 의한 유출량 저감 성능 분석 및 유역 내 설치 우선순위를 결정했다. PP와 RB의 설치를 통한 최대 유출 저감 성능 도출을 위해 최적 설계인자를 결정했고, 최적 설계인자를 반영한 PP와 RB의 우수 유출 저감 성능을 비교했다. 유출량의 시계열 변화로부터 첨두유출량 발생 전에는 PP가, 첨두유출량 발생 후에는 RB가 유출량 저감에 더 우수한 성능을 나타냈다. PP와 RB의 설치에 따른 소유역 별 총 유출량, 첨두유출량 저감 성능을 비교한 결과, PP의 경우 유역면적이 큰 소유역에서 RB보다 더 높은 우수 유출저감 성능을 나타냈고 RB는 불투수면적 비율이 높은 지역에서 더 높은 성능을 나타냈다. PP와 RB의 우수 유출 저감 성능 평가 결과를 통해 목감천유역 내 두 시설의 설치 우선 순위를 결정했다. 그 결과, PP와 RB 모두 유역면적, 불투수면적 비율이 높은 소유역에서 높은 우선 순위가 나타났다. 또한 우수 유출 저감 성능 평가 순위와 유역특성 간 상관관계를 비교한 결과, 상위 25%의 우수 유출 저감 성능을 나타낸 소유역에서는 불투수면적외에도 유역의 형상 인자와 높은 상관관계를 보였다. 이를 통해 기존 도심 지역에 우수유출저감시설 설치 우선 순위 결정 시 불투수면적 비율과 함께 유역의 형상 인자를 함께 고려해야 함을 알 수 있다.

• ETRI Journal
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• 제31권5호
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• pp.510-517
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• 2009

A high throughput parallel decoding method is developed for context-based adaptive variable length codes. In this paper, several new design ideas are devised and implemented for scalable parallel processing, a reduction in area, and a reduction in power requirements. First, simplified logical operations instead of memory lookups are used for parallel processing. Second, the codes are grouped based on their lengths for efficient logical operation. Third, up to M bits of the input stream can be analyzed simultaneously. For comparison, we designed a logical-operation-based parallel decoder for M=8 and a conventional parallel decoder. High-speed parallel decoding becomes possible with our method. In addition, for similar decoding rates (1.57 codes/cycle for M=8), our new approach uses 46% less chip area than the conventional method.

• 항공우주시스템공학회지
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• 제4권2호
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• pp.26-31
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• 2010

Reduction of the aerodynamic drag is one of the most hot issues of car industries. Many researchers have studied in the area of drag reduction methodology using experimental tools or numerical tools. In general, car shape design is the main focus to reduce the drag in aerodynamic research area. However, not many people have studied the aerodynamic interference between running cars to figure out the drag variation. In this research, the aerodynamic interference between two running cars have been analyzed by using numerical tools, FLUENT 6.2. Several different models of cars and two different distances between two running cars are considered.