• The Korean Journal of Ecology
• /
• 제23권4호
• /
• pp.293-298
• /
• 2000

To study the effect of global warming on the growth of plants and plant populations throughout their life cycle under a field-like condition, we constructed a Temperature Gradient Chamber (TGC) in Tsukuba, Japan. The chamber had slender shape : 30 m long. 3 m wide, and 2.5 m high. That satisfactory performance was confirmed by a test throughout all seasons in 1998: the projected global warming condition in the near future was simulated. That is, independent of a great daily or seasonal change in ambient meteorological conditions, air temperatures at the air outlet were warmed 5$^{\circ}C$ higher than those at the ambient (the annual mean was 14.3$^{\circ}C$) with precision of ${\pm}$0.2$^{\circ}C$ (the annual means were 19.2$^{\circ}C$) with a rising rate of approximately 1$^{\circ}C$ every 5 m. This chamber will enable us to study the effects of global warming on growth of plants and plant populations because their abilities to control air temperature are excellent. TGC is expected that it would be utilized for studying the effect of global warming on plant growth under natural weather conditions.

• Structural Engineering and Mechanics
• /
• 제15권1호
• /
• pp.115-134
• /
• 2003

The Ting Kau Bridge in Hong Kong is a cable-stayed bridge comprising two main spans and two side spans. The bridge deck is supported by three towers, an end pier and an abutment. Each of the three towers consists of a single reinforced concrete mast which reduces its section in steps, and it is strengthened by transverse cables and struts in the transverse vertical plane. The bridge deck is supported by four inclined planes of cables emanating from anchorages at the tower tops. In view of the threat from typhoons, the dynamic behaviour of long-span cable-supported bridges in the region is always an important consideration in their design. This paper is devoted to the ambient vibration measurements of the bridge for evaluation of dynamic characteristics including the natural frequencies and mode shapes. It also describes the modelling of the bridge. A few finite element models are developed and calibrated to match with the field data and the results of subsequent structural health monitoring of the bridge.

• 한국전기전자재료학회논문지
• /
• 제11권12호
• /
• pp.1091-1098
• /
• 1998

Thermal stability of the electroless deposited Cu thin film was investigated. Cu/TaN/Si multilayer was fabricated by electroless-depositing Cu thin layer on TaN diffusion barrier layer which was deposited by MOCVD on the Si substrate, and was annealed in $H_2$ ambient to investigate the microstructure of Cu film with a post heat-treatment. Cu thin film with good adhesion was successfully deposited on the surface of the TaN film by electroless deposition with a proper activation treatment and solution control. Microstructural property of the electroless-deposited Cu layer was improved by a post-annealing in the reduced atmosphere of $H_2$ gas up to $600^{\circ}C$. Thermal stability of Cu/TaN/Si system was maintained up to $600^{\circ}C$ annealing temperature, but the intermediate compounds of Cu-Si were formed above $650^{\circ}C$ because Cu element passed through the TaN layer. On the other hand, thermal stability of the Cu/TaN/Si system in Ar ambient was maintained below $550^{\circ}C$ annealing temperature due to the minimal impurity of $O_2$ in Ar gas.

• 한국습지학회지
• /
• 제14권2호
• /
• pp.169-180
• /
• 2012

단양쑥부쟁이(Aster altaicus var. uchiyamae)는 한국특산식물이자 환경부 지정 멸종위기식물 II급으로 하천변에 서식하는 식물이다. 본 연구는 지구온난화가 단양쑥부쟁이의 생태적 반응에 미치는 영향을 알아보기 위해 $CO_2$농도와 온도가 상승된 처리구와 대조구에서 종자를 파종하고, 유식물을 키워 발아율, 식물계절학, 영양생장과 생식생장을 관찰하였다. 그 결과, 단양쑥부쟁이의 발아율은 대조구보다 처리구에서 더 낮았다. 처리구에서 살아있는 잎의 지속 시기는 대조구보다 더 길었다. 개화와 꽃의 지속 시기, 종자 성숙 시기는 처리구에서 더 느렸다. 지상부와 지하부 무게는 처리구에서 더 가벼웠다. 개체 당 꽃대 수와 꽃대 당 종자개수는 처리구에서 더 적었다. 개체 당 꽃대무게, 꽃대 당 종자무게 그리고 종자 한 개 무게는 처리구에서 더 가벼웠다. 이상으로 볼때, $CO_2$농도와 온도상승은 단양쑥부쟁이의 생태에 부정적인 영향을 준다.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2005년도 ICCAS
• /
• pp.1400-1404
• /
• 2005

This paper presents the temperature control of aluminum plate by using Peltier element. Peltier effect is heat pumping phenomena by electric energy as one of the thermoelectric effect. So if current is charged to Peltier element, it absorbs heat from low temperature side and emits heat to high temperature side. In this experiment, Peltier element is used to control the temperature of small aluminum plate with current control and operating cooling fan only while cooling duration. Operating cooling fan only while cooling duration is proper to get more rapid heating and cooling duration. As a result of experiment, it takes about 100sec period to repeating temperature between $35^{\circ}C$ and $70^{\circ}C$ and about 80sec from $40^{\circ}C$ to $70^{\circ}C$ in ambient air temperature $25^{\circ}C$ and while operating cooling fan only in cooling duration. Future aim is to apply this temperature control method in actuating SMHA(special metal hydride actuator) which is applicable in Siver project acting in low frequency range by using Peltier element for heating and cooling.

• 한국위성정보통신학회논문지
• /
• 제10권3호
• /
• pp.6-10
• /
• 2015

무선 에너지 하비스팅 기술은 주로 무선 통신 네트워크에서 전력소모가 적은 무선 통신 장치들을 동작시키기 위해 주변 환경으로부터 RF 신호를 수집, 에너지로 변환하는 기술로 최근 각광을 받고 있다. 이와 같은 기술과 기존의 인지무선(Cognitive Radio) 네트워크 모델을 기반으로, 본 논문에서는 적은 파워 소비를 하는 2차 유저(Secondary User)가 근처에서 동작 중인 1차 유저(Primary User)의 특정 거리 안에 존재할 때 1차 유저가 전송한 통신 신호로부터 무선에너지 하비스팅을 하고 특정 거리 밖에 존재할 때 우선 사용자에게 할당되어 있는 허가대역을 주기적으로 센싱, 선택적으로 접근하는 무선에너지 하비스팅 인지무선 네트워크 모델을 제시한다. 이 때 1차 유저와 2차 유저는 Poisson pont process로 분포되어있고 통신을 하고 있는 수신자들과 일정한 거리로 떨어져있다. 위와 같은 네트워크 모델에서 주어진 여러 가지 조건하에 2차 유저 네트워크 처리량을 최대화할 수 있는 최적의 프레임 주기, 전송파워, 2차 유저 밀도 제안하고 앞으로의 연구방향을 제시한다.

• Journal of Radiation Protection and Research
• /
• 제41권2호
• /
• pp.87-91
• /
• 2016

Background: A hand-held detector for an emergency response was developed for nuclide identification and to estimate the information of the ambient dose rate in the scene of an accident as well as the radioactivity of the contaminants. Materials and Methods: To achieve this, the most suitable sensor was first selected as a cadmium zinc telluride (CZT) semiconductor and the signal processing unit from a sensor and the signal discrimination and storage unit were successfully manufactured on a printed circuit board. Results and Discussion: The performance of the developed signal processing unit was then evaluated to have an energy resolution of about 14 keV at 662 keV. The system control unit was also designed to operate the CZT detector, monitor the detector, battery, and interface status, and check and transmit the measured results of the ambient dose rate and radioactivity. In addition, a collimator, which can control the inner radius, and the airborne dust sampler, which consists of an air filter and charcoal filter, were developed and mounted to the developed CZT detector for the quick and efficient response of a nuclear accident. Conclusion: The hand-held CZT detector was developed to make the in-situ gamma-ray spectrometry and its performance was checked to have a good energy resolution. In addition, the collimator and the airborne dust sampler were developed and mounted to the developed CZT detector for a quick and efficient response to a nuclear accident.

• Journal of Animal Science and Technology
• /
• 제60권4호
• /
• pp.7.1-7.5
• /
• 2018

Background: Mice are widely accepted research models of great clinical significance. Maintenance of laboratory mice breed is an essential aspect for performing research activities in various fields of science. Infanticide is one of the prominent causes of litter loss during maintenance of laboratory mice stock. The present study is an effort to monitor the effect of change in ambient temperature of female mice below the normal range on cannibalism and infanticide during early postparturition phase. Adult female Swiss albino mice have been divided into two groups of control and treatment. On the day of litter group one was maintained under controlled temperature conditions (minimum $20^{\circ}C$ to maximum $23^{\circ}C$) throughout, while female mice belong to group two have been exposed to variation of room temperature (maximum $15^{\circ}C$ to minimum $10^{\circ}C$ for two nights and one day) until 36 h postparturition. Results: The effects of temperature changes were observed on the infanticide behaviour of dams along with the survival of pups in early postparturition phase till 36 h after delivery. The significant statistical difference (P < 0.05) was reported in infanticide behaviour of dams when control and treatment group was compared. It is observed that decrement in surrounding temperature promotes decrement in the ambient body temperature of dams during early postparturition. It is proposed that alteration of hypothalamic homeostasis due to temperature change induces cannibalism and infanticide behaviour. Lack of thermoregulation during early postparturition creates the sense of insecurity, in-satiety, anxiety and stress. Conclusions: Authors strongly recommend the maintenance of body and surrounding temperature to prevent infanticidal behaviour and cannibalism within Swiss albino mice population. Further investigations are advisable to authenticate the active behavioural and biochemical pathway behind the phenomena.

• 수산해양기술연구
• /
• 제49권1호
• /
• pp.58-66
• /
• 2013

Most of steam power plant in Korea are heating the feed water system to prevent freezing water flowing in the pipe in winter time. The heating system is operated whenever the ambient temperature around the power plant area below 5 degree Centigrade. But this kind of heat supplying system cause a lot of energy consuming. If we think about the method that the temperature of the each pipe is controled by attaching the temperature measuring sensor like RTD sensor and heat is supplied only when the outer surface temperature of the pipe is under 5 degree Centigrade, then we can save a plenty of energy. In this study, the computer program package for simulation is used to compare the energy consumption load of both systems. Energy saving rate is calculated for the location of Youngweol area using the data of weather station in winter season, especially the January' severe weather data is analyzed for comparison. Various convection heat transfer coefficients for the ambient air and the flowing water inside the pipe was used for the accurate calculation. And also the various initial flowing water temperature was used for the system. Steady state analysis is done previously to approximate the result before the simulation. The result shows that the temperature control system using RTD sensor represents the high energy saving effect which is more than 90% of energy saving rate. Even in the severe January weather condition, the energy saving rate is almost 60%.

• 한국환경보건학회지
• /
• 제45권2호
• /
• pp.186-191
• /
• 2019

Objectives: Subway is one of the most common transportation modes in Seoul, Korea. The objectives of this study were to determine characteristics of in-cabin $PM_{2.5}$ concentration in Seoul Metro Line Number 2 and to identify factors of the $PM_{2.5}$ concentration. Methods: In-cabin $PM_{2.5}$ concentrations in Seoul Metro Line Number 2 were measured using real-time monitors and the factors affecting $PM_{2.5}$ concentration in cabin were observed. Linear regression analysis of in-cabin $PM_{2.5}$ concentration and indoor/outdoor (I/O) ratio were performed. Results: In-cabin $PM_{2.5}$ concentration was associated with the in-cabin $PM_{2.5}$ concentration in previous station. In-cabin $PM_{2.5}$ concentration was correlated with ambient $PM_{2.5}$ concentration and associated with underground station with control of the in-cabin $PM_{2.5}$ concentration in previous station. I/O ratio increased as the number of passengers increased and when passing through the underground station with control of I/O ratio in previous station. Conclusion: In-cabin $PM_{2.5}$ concentration was affected by ambient $PM_{2.5}$ concentration. Therefore, management of in-cabin $PM_{2.5}$ concentrations should be based on outdoor air quality.