• 한국구조물진단유지관리공학회 논문집
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• 제15권6호
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• pp.100-109
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• 2011

최근 중앙경간 일부를 강박스 거더로 대체하여 자중을 감소시켜 중앙경간의 장경간화를 시도한 교량형식인 콘크리트-강 복합 엑스트라도즈드교는 기존 엑스트라도즈드 교량을 개선하기 위한 대안으로 제시되고 있다. 콘크리트-강 복합 엑스트라도즈드교는 자중 감소를 통해 중앙경간의 장경간화가 가능할 뿐 아니라 기존형식과 동일한 경우 주거더의 높이와 측경간을 감소시킬 수 있어 구조적 효율성이 매우 우수한 형식으로 평가되고 있다. 따라서 콘크리트-강 복합 엑스트라도즈드교에 대한 최적의 설계기법을 구축하는 것이 매우 중요하다. 이를 위하여 본 연구에서는 콘크리트-강 복합 엑스트라도즈드교에 대한 주요 설계변수(주탑 높이, 주거더 높이 및 강상판 거더 길이)를 도출하고, 이를 바탕으로 설계변수별 수치해석과 그 결과를 이용한 설계변수별 민감도 분석을 실시하여 설계변수가 교량의 설계에 미치는 영향을 정량적으로 반영할 수 있는 설계가중값을 도출하였다.

• 한국구조물진단유지관리공학회 논문집
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• 제19권5호
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• pp.22-29
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• 2015

현대의 구조물은 고층화, 대형화 되어가는 추세이다. 보통중량 콘크리트는 강도에 비해 질량이 크기 때문에 구조물의 자중을 증가시킨다는 단점이 있다. 그러므로, 추세에 맞는 콘크리트의 경량화가 필요한 실정이다. 콘크리트의 경량화 방법 중 하나가 경량골재를 사용한 경량골재 콘크리트이다. 하지만, 국내에서는 경량골재 콘크리트에 대한 인식부족으로 인하여 구조용 경량골재 콘크리트에 대한 연구가 부족한 실정이다. 경량골재 콘크리트에 사용되는 경량골재의 품질에 따라 콘크리트의 물성 및 강도에 대한 검증이 필요하다. 본 연구에서는 보통골재와 경량골재를 사용한 콘크리트를 제작하고 인장균열파괴실험을 통해 하중-CMOD곡선은 얻고, 이를 역해석하여 파괴에너지를 도출하였다.

• 아시안잔디학회지
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• 제20권2호
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• pp.167-174
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• 2006

키토산 처리에 의한 크리핑 벤트그래스의 생장에 미치는 영향에 대하여 분석하였다. 엽장은 무처리 평균은 25.1cm로 확인되었고, 키토산 500배 처리 시 평균 31.6cm로 가장 높은 생육증가를 나타내었다. 엽수는 무처리 시 평균은 27.9매로 나타났고, 키토산 300배 처리 시 45.5 매로 증가하였다. 뿌리길이는 무처리에서 21.1cm인 것으로 나타났으나, 키토산 600배 처리 시 27.9cm로 뿌리 길이의 생육이 증가하는 것으로 나타났다. 엽록소 함량은 무처리 시에서 $11.9mg/100cm^2$로 나타났고, 키토산 300배 처리에서 $18.4mg/100cm^2$로 최대 증가를 나타내었다. 뿌리길이의 생장, 엽록소 함량, 지상부 생체중과 건물중, 지하부 생체중과 건물중은 키토산 500배 처리 농도에서 가장 높은 생장 특성을 나타냈다.

• 항공우주시스템공학회지
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• 제17권6호
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• pp.27-34
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• 2023

본 논문은 마그네틱 기어를 적용한 항공기용 전기추진시스템에 관하여 기술한다. 항공기 추진모터는 높은 토크가 요구되기 때문에 감속기를 결합하여 토크를 증대시킬 수 있다. 하지만 기계식 기어는 마찰에 의한 손실과 열 및 진동 등으로 인해 잦은 유지 보수가 필요하다. 기계식 기어를 사용하지 않는 직접구동형 전동기의 경우 고 토크를 달성하기 위한 설계 시 전동기의 크기와 중량이 증가하게 된다. 본 논문은 항공기의 전기추진 시스템에서 기계식 기어의 유지보수와 직접구동형 전동기의 중량 증가 문제를 해결하기 위해 마그네틱 기어 적용 방안을 제안한다. 항공기용 전기추진 시스템에 적합한 마그네틱 기어를 설계하고 직접구동형 전동기와 성능을 비교함으로 마그네틱 기어의 적용 가능성을 확인한다.

• 한국인공지능학회지
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• 제6권1호
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• pp.1-10
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• 2018

Compressed Air is an important energy source used in most factories nowadays. The automation trend using air compressor has been gradually increasing with the interest of the 4th industry in recent years. With the air compressor system, it is possible to construct the device at low cost and easily achieve automation and energy saving. In addition, With trend of FA, miniaturation and light weight manufacturing trend expand their use in the electronics, medical, and food sectors. Research method is to design the technology for the remote control of the following information as USN base. Development of flexible sensing module from real time observation module for fusion of IT technology in compressed air systems, design and manufacture of flexible sensing module, and realiability assessment. Design of real-time integrated management system for observation data of compressed air system - Ability to process observation data measured in real time into pre-processing and analysis data. This study expects unconventionally decreasing effect of energy cost that takes up 60~70% of air compressor layout and operation and maintenance management cost through USN(Ubiquitous Sensor Network) technology by using optimum operational condition from real time observation module. In addition, by preventing maintenance cost from malfunction of air compressor beforehand, maintenance cost is anticipated to cut back.

• Asian-Australasian Journal of Animal Sciences
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• 제1권4호
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• pp.185-187
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• 1988

A total of 22 energy balance trials were done for calves fed a liquid milk replacer, calf starter and second cut mixed hay during weaning period. Milk replacer supplied 50% of the total dietary energy, calf starter 42% and hay 8% Live weight of calves averaged 64.6 ($S.D.{\pm}7.8$) kg and daily gain 0.54 (${\pm}0.22$) kg. The metabolizability of gross energy averaged 0.751. A regression was calculated relating energy retention (ER, $kJ/kg^{0.75}$) to the intake of metabolizable energy (IME, $kJ/kg^{0.75}$): $$ER=0.69({\pm}0.09)IME-395,\;r=0.888,\;P<0.01,\;S.E.{\pm}7.1$$. Metabolizable energy for maintenance (MEm) was calculated to be $572kJ/kg^{0.75}$ when ER = 0. The amount of IME over MEm for an individual animal (MEg, $kJ/kg^{0.75}$) was regressed on average daily gain (ADG, kg) by the method of regression through the origin: $$MEg=364({\pm}55)ADG,\;r=0.634,\;P<0.01,\;S.E.{\pm}12$$. The amount of ME required for maintenance and growth was estimated to be $936kJ/kg^{0.75}$.

• Asian-Australasian Journal of Animal Sciences
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• 제1권2호
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• pp.61-63
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• 1988

A total of 38 energy balance trials were done for calves fed a liquid milk replacer, calf starter and second cut mixed hay. Milk replacer supplied 81% of the total dietary energy. Live weight of calves averaged 54.1 (S.D 6.2) kg and daily gain 0.37 (${\pm}0.23$)kg. The metabolizability of gross energy averaged 0.822. A regression was calculated relating energy retention (ER, $kJ/kg^{0.75}$) to the intake of metabolizable energy (IME, $kJ/kg^{0.75}$): ER = 0.72 (${\pm}0.12$) IME - 330, r = 0.702, P < 0.01, $S.E.{\pm}18.0$. Metabolizable energy for maintenance (MEm) was calculated to be $458kJ/kg^{0.75}$ when ER = 0. The amount of IME over MEm for an individual animal (Meg, $kJ/kg^{0.75}$) was regressed on averaged daily gain (ADG, kg): Meg = 413 (${\pm}91$) ADG + 0.2, r = 0.650, P < 0.01, $S.E.{\pm}21$. The amount of ME requirement for suckling calves was estimated using values obtained above.

• Journal of Dental Anesthesia and Pain Medicine
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• 제18권3호
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• pp.169-175
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• 2018

Background: The objective of this study was to compare hemodynamic and recovery characteristics of total intravenous anesthesia using propofol target-controlled infusion (TCI) versus sevoflurane for extraction of four third molar teeth. Methods: One hundred patients undergoing extraction of four third molar teeth under general anesthesia were randomized to one of two groups. Group 1 received propofol TCI-oxygen for induction and propofol TCI-oxygen-air for maintenance. Group II received a propofol bolus of 2 mg/kg for induction and sevoflurane-oxygen-air for maintenance. Heart rate, mean arterial pressure (MAP), operating time, time to emergence, nausea and vomiting, and sedation and pain scores were measured in each group. Results: Demographic data, including age, gender, weight, and height, were not significantly different between the two groups. The MAP was significantly higher after intubation (P = 0.007) and injection of anesthesia (P = 0.004) in the propofol group than in the sevoflurane group, with significant reflex bradycardia (P = 0.028). The mean time to emergence from anesthesia using propofol was 25 s shorter than that of sevoflurane (P = 0.02). Postoperatively, the propofol group was less sedated than the sevoflurane group at 30 min (0.02 versus 0.12), but this difference was not significant (P = 0.065). Conclusion: Both propofol TCI and sevoflurane are good alternatives for induction and maintenance of anesthesia for short day-case surgery. However, propofol TCI does not blunt the hemodynamic response to sudden, severe stimuli as strongly as sevoflurane, and this limitation may be a cause for concern in patients with cardiac comorbidities.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 봄 학술논문 발표대회
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• pp.155-156
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• 2020

Unlike new construction projects, road paving maintenance work shows large productivity discrepancies depending on the conditions of the worksite. The current construction cost calculation scheme, however, only provides daily construction volume categorized by work scope and scale: There are no detailed standards that can be implemented on various types of worksites. To develop standards that enable the calculation of appropriate construction costs by taking into account worksite conditions, the current study conducted on-site surveys and interviews. The on-site research and analysis revealed that location, construction width, the day's worksite lot, work scope, and construction objectives were found to cause differences in construction volume. In addition to the existing work scope and work scape variables, the current study added weight constants reflecting the daily work volume based on movement conditions at site and the size of the worksite lot. In this process, the current study found that even one type of construction project can have fifteen different levels of daily construction volume. Such detailed classification was deemed to enable the proper calculation of construction costs based on worksite conditions.

• Nutritional Sciences
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• 제5권4호
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• pp.221-227
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• 2002

The objective of this study was to examine the effects of a weight loss program on the degree of obesity and levels of resting energy expenditure (REE) in overweight subjects according to their mitochondrial uncoupling protein 2 (UCP 2) genotype. Twenty-three subjects with a body mass index (BMI) greater than 27 were recruited from the Obesity Clinic of the Kyung-Hee University Hospital during the period of December 2000 - August 2001. The subjects were genotyped for the exon 8 allele; 15 subjects were found to be of del/del genotype, 8 were del/ins, and none were of ins/ins genotype. No significant association was found between the different UCP 2 genotypes and the initial levels of weight, fat mass (FM), lean body mess (LBM), BMI, REE, and REE/LBM ratio. After 12 weeks of a weight loss program, body weight and FM were significantly decreased, while LBM, total body water (TBW), and REE were not changed, irrespective of UCP 2 genotype. Initial fasting plasma levels of albumin, glucose, triglyceride, lipoprotein cholesterol, insulin, free triiodo-thyronine (T3), free fatty acid (FFA), and leptin were not different according to the UCP 2 genotype; furthermore, these blood parameters were not changed after the 12-week weight loss program. However, plasma levels of leptin decreased in both the del/del and ins/del genotypes, from 18.7 ng/ml to 13.4 ng/ml (p<.05), and from 18.1 ng/ml to 13.9 ng/ml (p＜.05), respectively, after the weight loss program. In conclusion, this study found no significant association between the del/del or del/ins UCP 2 genotypes and differing levels of REE or differing degrees of obesity, either before or after a weight loss program. This study provided evidence that a well- managed weight loss program could maintain levels of REE, which plays an important role in the maintenance of energy balance.