• 한국환경과학회지
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• 제13권3호
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• pp.319-325
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• 2004

An experimental study on the preparation of monolithic porous polymers by environmentally friend process in supercritical carbon dioxide has been carried out. Polymerization mixture composed of a cross-linking monomer, initiator and functional co-polymer was charged in the reactor with sapphire window. After the system was purged with a flow of $CO_2$ for 15 min, the reactor was pressurized with liquid $CO_2$ up to 100 bars. The reactor was isolated from and placed back to the system via quick connector for shaking until the mixture had become fully homogeneous. The reactor was then heated and pressurized to the required reaction conditions and left overnight. After cooling and $CO_2$ evacuation, the polymer was removed from the reactor as dry, white, continuous monoliths. The effect of experimental conditions on the physical properties of porous polymer was systematically examined, and it was found that monomer content had a major effect on the physical properties of the polymers.

• Clinical and Experimental Pediatrics
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• 제54권12호
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• pp.481-488
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• 2011

In the current era of low-birth rate in Korea, it is important to improve our neonatal intensive care and to establish an integrative system including a regional care network adequate for both high-risk pregnancies and high-risk newborn infants. Therefore, official discussion for nation-wide augmentation, proper leveling, networking, and regionalization of neonatal and perinatal care is urgently needed. In this report, I describe the status of neonatal intensive care in Korea, as well as nationwide flow of transfer of high-risk newborn infants and pregnant women, and present a short review of the regionalization of neonatal and perinatal care in the Unites States and Japan. It is necessary not only to increase the number of neonatal intensive care unit (NICU) beds, medical resources and manpower, but also to create a strong network system with appropriate leveling of NICUs and regionalization. A systematic approach toward perinatal care, that includes both high-risk pregnancies and newborns with continuous support from the government, is also needed, which can be spearheaded through the establishment of an integrative advisory board to propel systematic care forward.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2005년도 제31회 KOSCO SYMPOSIUM 논문집
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• pp.287-293
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• 2005

Most of all combustion system has combustion instability. It is a serious problem in combustion system. Unstable injection is one of the source of combustion instability. The experimental investigation of spray characteristics for simplex swirl injector were conducted experimentally. Two kerosene based fuels were chosen as the atomizing fluid. As the major operating parameters, fuel temperature and injection pressure were chosen, and varied in the range from 253 K to 293 K and from 0.2 MPa to 1.0 MPa, respectively. Direct spray images and mean diameter were measured for the various combination of operating parameters in the flow field. The results of present study show that the injection pressure and spray cone angle are fluctuated at specific conditions while it is continuous steady injection. As the fuel temperature changes continuously, spray cone angle varies discontinuously through the region of injection instability.

• KIEAE Journal
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• 제13권1호
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• pp.75-81
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• 2013

The balcony of our apartment building consists of unique construction similar to double skin. It is announced broadly that double skin is very effective system in improvement of natural ventilation and indoor thermal environment, and outdoor sound protection. So, for the improvement of indoor climate and energy saving, many peoples studied about environmental performance of our balcony construction. This study focus on shaft box facade, special form of box window construction. It consists of a system of box window with continuous vertical shafts that extend over a number of stories to create a stack effect. Proto-type was decided by analyzing various types of exiting apartments. Shaft box type balcony was created by setting up shaft space at a part of balcony. Air flow and contribution of air temperature were simulated, performance of shaft box type balcony was compared with existing balcony. Finally, we confirmed that shaft box type balcony has many possibility for improvement of indoor environment.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.493-497
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• 2011

Project delivery systems have evolved over the years. Continuous changes in technology and the increasing sophistication in buildings required specialization of design and construction services. IPD as a delivery method has been used in the USA and other countries. With the development of BIM, lots of construction companies have been realizing this method since BIM came out in China. However IPD are not considered with BIM, IPD will be an important role in management system of construction. This study introduced the definition of IPD and based on the flow process of IPD, compared the process in china and other countries. Through the real project and the condition in China this paper analyzed the feasibility of IPD in China.

• Journal of Biosystems Engineering
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• 제30권1호
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• pp.32-37
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• 2005

This study was conducted the slurry pig manure treatment by condensation drying of liquid from the slurry manure with a heat-pump and electric heater combined with air flow channel system. The system was designed as liquid and solid matters separation of slurry manure, and it can doing continuous input of slurry manure from a pig house, and it can operated year round use for pig farms. The separation of liquid and solid matters from slurry manure needed the prevention of solid accumulation in the system. The system was designed as closed space from outside air space for maximized evaporation of liquid and the condensation of liquid from slurry manure. The system can be operated the pig slurry manure treatment regardless of seasons in a yew. The separated evaporation water from the pig slurry manure by the heat-pump was satisfactorily pure water that can be used as washing water in livestock farms. The system can applicate to about 100 heads of pig, and the proper area of evaporation plate system was considered around $10\;m^2$. The input electrical energy of about 15 kWh which the cost equal to 250,000 won per month.

• 한국가시화정보학회지
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• 제14권1호
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• pp.57-61
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• 2016

We report a finding of fast(exceeding 2,000 K/s) heating of polydimethylsiloxane(PDMS), one of the most commonly-used microchannel materials, under cyclic loadings at high(~MHz) frequencies. A microheater was created based on the finding. The heating mechanism utilized vibration damping of sound waves, which were generated and precisely manipulated using a conventional surface acoustic wave(SAW) microfluidic system, in PDMS. The penetration depths were measured to range from $210{\mu}m$ to $1290{\mu}m$, enough to cover most microchannel heights in microfluidic systems. The energy conversion efficiency was SAW frequency-dependent and measured to be the highest at around 30 MHz. Independent actuation of each interdigital transducer(IDT) enabled independent manipulation of SAWs, permitting spatiotemporal control of temperature on the microchip. All the advantages of this microheater facilitated a two-step continuous flow polymerase chain reaction(CFPCR) to achieve the billion-fold amplification of a 134 bp DNA amplicon in less than 3 min. In addition, a technique was developed for establishing dynamic free-form temperature gradients(TGs) in PDMS as well as in gases in contact with the PDMS.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.545-546
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• 2007

A hybrid system that uses a parallel combination of wind turbine and fuel cell is modeled. Wind energy source is characterized by its intermittent and variable nature. The output power generated by the fuel cell is stable and can be properly controlled. Therefore, fuel cell system can be added to the wind turbine system for the purpose of ensuring continuous power flow. Fuel cell helps to compensate power and regulate the frequency in power system. Simulation results show the effect of the hybrid system on power regulation. The excess power generated by the wind turbine was directed to an electrolyzer to generate hydrogen and the power deficit was compensated by the fuel cell.

• Advances in environmental research
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• 제4권2호
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• pp.105-117
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• 2015

The groundwater is a very important part of the environment and must be protected for the benefit of the present and future generation. The contamination of soil and groundwater by chemicals has become an increasing concern in the recent past. These chemicals enter the groundwater system by a wide variety of mechanisms, including accidental spills, land disposal of domestic and industrial wastes and application of agricultural fertilizers. Once introduced into an aquifer, these contaminants will be transported by flowing groundwater and may degrade water quality at nearby wells and streams. For improving the management and protection of groundwater resources, it is important to first understand the various processes that control the transport of contaminants in groundwater. Predictions of the fate of groundwater contaminants can be made to assess the effect of these chemicals on local water resources and to evaluate the effectiveness of remedial actions. In this study, an attempt has been made to investigate the behaviour of solute transport through porous media using laboratory experiments. Sodium chloride was used as a conservative chemical in the experiment. During the experiment, pulse boundary condition and continuous boundary conditions were used. Experimental results have been presented for conservative solute transport in the sand. The pattern of the break through curve remains almost same in all the cases of varying flow rate and initial concentration of conservative chemical.

• 대한기계학회논문집B
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• 제31권12호
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• pp.994-1001
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• 2007

Numerical analysis has been carried out to investigate air-side convective heat transfer characteristics in a compact heat exchanger with circular tubes and continuous plate fins. Simulation results such as air velocity and temperature distributions are presented, and heat transfer coefficients are compared with previous experimental correlations. Three models of standard and RNG $k-{\varepsilon}$, and Reynolds stress are applied for turbulence model applicability. Predicted heat transfer coefficient from the models of standard and RNG $k-{\varepsilon}$ are very close to those of the heat transfer correlations while there are relatively large difference, more than 17 percentage in the result from the Reynolds stress model. From the calculated results a correlation for Colburn j factor in the compact heat exchanger system is suggested.