• 한국조경학회지
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• 제40권6호
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• pp.190-197
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• 2012

본 연구는 저관리 경량형 옥상녹화의 열수지를 정량화하기 위하여 모의실험을 수행하였다. 콘크리트블록을 이용하여 가로 $1.2m{\times}$세로 $1.2m{\times}$높이 1m의 모의실험구 2개를 제작하여 하나는 한국잔디를 식재한 토심 10cm의 옥상녹화 실험구로 하였으며, 옥상녹화를 실시하지 않은 나머지 하나는 대조구로 하였다. 2012년 6월 6일~7일에 기온, 상대습도, 풍향, 풍속 등 외부 기상환경, 증발산량, 옥상녹화와 대조구인 콘크리트의 표면과 천장면의 온도, 열류량, 열수지를 측정하였다. 6일과 7일의 일최고기온은 각각 $29.4^{\circ}C$와 $30^{\circ}C$로 초여름 날씨로는 매우 무더웠다. 6일과 7일의 일증발산량은 각각 $2,686.1g/m^2$과 $3,312.8g/m^2$이었으며, 일사량이 증가함에 따라 증발산량도 증가하였다. 외부 기온이 가장 높은 시간일 때의 옥상녹화 표면과 대조구 표면의 온도차이를 비교해 보면 대조구 표면이 $5.5^{\circ}C$(6일)와 $2.2^{\circ}C$(7일) 더 높은 것으로 나타났다. 옥상녹화 천장과 대조구 천장의 온도차이를 비교해 보면 $13.1^{\circ}C$(6일)와 $14.2^{\circ}C$(7일)로 나타나 옥상녹화에 의한 실내온도저감효과가 매우 큰 것으로 나타났다. 옥상녹화와 대조구인 콘크리트 표면의 열수지를 분석한 결과, 옥상녹화는 순복사량과 잠열량이 많은 비율을 차지하고 있었으나 대조구는 현열량과 전도열량의 비율이 높았다. 즉, 옥상녹화는 한국잔디와 식재토양에 의한 증발산으로 열을 식혀주는 잠열의 비율이 높은 반면에 대조구인 콘크리트 표면은 식물이 식재되어 있지 않기 때문에 열을 식혀주는 잠열은 $0W/m^2$인 반면에 주위 온도를 증가시키는 현열량과 건물내로 전달되는 전도열량의 비율이 높아 표면과 천장면의 온도를 상승시켰다. 본 연구는 옥상녹화의 온도저감과 열수지 해석을 시도했다는 점에서는 매우 의의가 크다고 할 수 있지만, 옥상녹화는 토심과 토양배합비, 식물종, 계절 등 여러 변수에 따라 온도저감효과가 다르게 나타날 수 있기 때문에 이에 대한 후속연구가 필요하다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.104-104
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• 2015

Due to the demand of the cold neutron flux in the neutron science and beam utilization technology, the cold neutron source (CNS) has been constructed and operating in the nuclear research reactor all over the world. The majority of the heat load removal scheme in the CNS is two-phase thermosiphon using the liquid hydrogen as a moderator. The CNS moderates thermal neutrons through a cryogenic moderator, liquid hydrogen, into cold neutrons with the generation of the nuclear heat load. The liquid hydrogen in a moderator cell is evaporated for the removal of the generated heat load from the neutron moderation and flows upward into a heat exchanger, where the hydrogen gas is liquefied by the cryogenic helium gas supplied from a helium refrigeration system. The liquefied hydrogen flows down to the moderator cell. To keep the required liquid hydrogen stable in the moderator cell, the CNS consists of an in-pool assembly (IPA) connected with the hydrogen system to handle the required hydrogen gas, the vacuum system to create the thermal insulation, and the helium refrigeration system to provide the cooling capacity. If one of systems is running out of order, the operating research reactor shall be tripped because the integrity of the CNS-IPA is not secured under the full power operation of the reactor. To prevent unscheduled reactor shutdown during a long time because the research reactor has been operating with the multi-purposes, the introduction of the standby cooling system (STS) can be a solution. In this presentation, the design considerations are considered how to design the STS satisfied with the following objectives: (a) to keep the moderator cell less than 350 K during the full power operation of the reactor under loss of the vacuum, loss of the cooling power, loss of common electrical power, or loss of instrument air cases; (b) to circulate smoothly helium gas in the STS circulation loop; (c) to re-start-up the reactor within 1 hour after its trip to avoid the Xenon build-up because more than certain concentration of Xenon makes that the reactor cannot start-up again; (d) to minimize the possibility of the hydrogen-oxygen reaction in the hydrogen boundary.

• 설비공학논문집
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• 제18권1호
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• pp.24-30
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• 2006

Three liquid cooling heat exchangers for cooling of telecommunication equipment were designed and their cooling performances were tested. The liquid cooling heat exchangers had twelve rectangular channels $(5\times3 mm)$ with different flow paths of 1, 4, and 12. Silicon rubber heaters were used to provide heat flux to the test section. Heat input was varied from 75 to 400 W, while flow rate and inlet temperature of working fluid were altered from 1.2 to 4.0 liter/fin and from 15 to 3$30^{\circ}C$, respectively. The 4-path heat exchanger showed lower and more uniform average inner temperatures between heaters and the surface of heat exchanger than those of the others. To obtain optimal distribution of working fluid to each channels of liquid cooling heat exchangers, 2-3-2 and 4-3 type tube distributors were designed, and their distribution performances of working fluid were numerically and experimentally investigated. The distributor of the 2-3-2 type showed superior distribution performance compared with those of the 4-3 type distributor.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2001년도 제34회 학술심포지움
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• pp.3-8
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• 2001

Isopentenyl diphosphate (IPP) is the common, five-carbon building block in the biosynthesis of all carotenoids, IPP in Escherichia coli is synthesized through the non-mevalonate pathway. The first reaction of IPP biosynthesis in E. coli is the formation of 1-deoxy-D-xylulose-5-phosphate (DXP), catalyzed by DXP synthase and encoded by dxs. The second reaction in the pathway is the reduction of DXP to 2-C-methyl-D-erythritol-4-phosphate, catalyzed by DXP reductoisomerase and encoded by dxr. To determine if one or more of the reactions in the non-mevalonate pathway controlled flux to IPP, dxs and dxr were placed on several expression vectors under the control of three different promoters and transformed into three E. coli strains (DH5(, XL1-Blue, and JM101) that had been engineered to produce lycopene. Lycopene production was improved significantly in strains transformed with the dxs expression vectors. When the dxs gene was expressed from the arabinose-inducible araBAD promoter (PBAD) on a medium-copy plasmid, lycopene production was 2-fold higher than when dxs was expressed from the IPTG-inducible trc and lac promoters (Ptrc and Plac, respectively) on medium-copy and high-copy plasmids, Given the low final densities of cells expressing dxs from IPTG-inducible promoters, the low lycopene production was probably due to the metabolic burden of plasmid maintenance and an excessive drain of central metabolic intermediates. At arabinose concentrations between 0 and 1.33 mM, cells expressing both dxs and dxr from PBAD on a medium-copy plasmid produced 1.4 - 2.0 times more lycopene than cells expressing dxs only. However, at higher arabinose concentrations lycopene production in cells expressing both dxs and dxr was lower than in cells expressing dxs only. A comparison of the three E. coli strains transformed with the arabinose-inducible dxs on a medium-copy plamid revealed that lycopene production was highest in XL1-Blue.

• 한국세라믹학회지
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• 제45권8호
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• pp.477-481
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• 2008

$Eu^{2+}$ and $Dy^{3+}$ co-doped strontium aluminate, $SrAl_2O_4$ long phosphorescent phoshor was fabricated and its photoluminescence was characterized. The phosphor, $SrAl_2O_4:Eu^{2+},Dy^{3+}$ was synthesized by a coprecipitation in which metal salts of $Sr(NO_3)_2$, $Al(NO_3)_3{\cdot}9H_2O$, were dissolved in $(NH_4)_2CO_3$ solution with adding $Eu(NO_3)_3{\cdot}5H_2O$ and $Dy(NO_3)_3{\cdot}5H_2O$ as a activator and co-activator, respectively. The coprecipitated products were separated from solution, washed, and dried in a vacuum dry oven. The dried powders were then mixed with 3 wt% $B_2O_3$ as a flux and heated at $800{\sim}1400^{\circ}C$ for 3 h under the reducing ambient atmosphere of 95%Ar+$5%H_2$ gases. For the synthesized $SrAl_2O_4:Eu^{2+},Dy^{3+}$, properties of photoluminescence such as emission, excitation and decay time were examined. The emission intensity increased as the annealing temperature increased and showed a maximum peak intensity at 510 nm with a broad band from $400{\sim}650\;nm$. Monitored at 520 nm, the excitation spectrum showed a maximum peak intensity at $315{\sim}320\;nm$ wavelength with a broad band from $200{\sim}500\;nm$ wavelength. The decay time of $SrAl_2O_4:Eu^{2+},Dy^{3+}$ increased as the annealing temperature increased.

• 한국환경과학회지
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• 제11권6호
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• pp.489-496
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• 2002

The purpose of this study was to investigate spatial distributions of total deposition. A total number 79 samples were collected at 17 sampling sites from September 1999 to January 2000. Total (=wet+dry) atmospheric depositions were collected by filtered deposition sampler at sampling site (the Western Part of Kyongsangnam Province). In addition, the deposition of soluble and insoluble fraction was also investigated to find a suitable simplified collection method for a long-term monitoring of total deposition. The total depositions were measured soluble amount(mm/month), insoluble amount(kg/km$^2$/month), pH, conductivity(E.C.) and eight ionic components. The spatial distribution of deposition flux was to estimated by using a kringing analysis. The 17 sites mean fluxes of water soluble ionic components; SO$_4$$\^$2-/, Cl$\^$-/, NO$_3$$\^$-/, Na$\^$+/, NH$_4$$\^$+/, K$\^$+/, Mg$\^$2+/, Ca$\^$2+/ were 100.7∼315.6kg/km$^2$/month, 30.1∼234.3kg/km$^2$/month, 64.4∼ 139.4kg/km$^2$/month, 7.5∼68.3kg/km$^2$/month, 10.7∼48.7kg/km$^2$/month, 5.6∼27.9kg/km$^2$/month, 4.5∼17.5kg/km$^2$/month, 27.6∼81.7kg/km$^2$/month, respectively.

• 대한기계학회논문집A
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• 제33권2호
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• pp.179-184
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• 2009

The Fuel Test Loop(FTL) which is capable of an irradiation testing under a similar operating condition to those of PWR(Pressurized Water Reactor) and CANDU(CANadian Deuterium Uranium reactor) nuclear power plants has been developed and installed in HANARO, KAERI(Korea Atomic Energy Research Institute). It consists of In-Pile Section(IPS) and Out-of Pile System(OPS). The IPS, which is located inside the pool is divided into 3-parts; the in-pool pipes, the IVA(IPS Vessel Assembly) and the support structures. The test fuel is loaded inside a double wall, inner pressure vessel and outer pressure vessel, to keep the functionality of the reactor coolant pressure boundary. The IVA is manufactured by local company and the functional test and verification were done through pressure drop, vibration, hydraulic and leakage tests. The brazing technique for the instrument lines has been checked for its functionality and performance. An IVA has been manufactured by local technique and have finally tested under high temperature and high pressure. The IVA and piping did not experience leakage, as we have checked the piping, flanges, assembly parts. We have obtained good data during the three cycle test which includes a pressure test, pressure and temperature cycling, and constant temperature.

• 센서학회지
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• 제16권1호
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• pp.17-23
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• 2007

This paper presents a miniaturized turn-counting sensor (TCS) where the geomagnetism and high-rpm rotation of ammunition are used to detect the turn number of ammunition for applications to small-caliber turn-counting fuzes. The TCS, composed of cores and a coil, has a robust structure with no moving part for increasing the shock survivability in the gunfire environments of ${\sim}30,000$ g's. The TCS is designed on the basis of the simulation results of an electromagnetic analysis tool, $Maxwell^{(R)}$3D. In experimental study, the static TCS test using a solenoid-coil apparatus and the dynamic TCS test (firing test) have been made. The presented TCS has shown that the induction voltage of $6.5{\;}mV_{P-P}$ is generated at the magnetic flux density of 0.05 mT and the rotational velocity of 30,000 rpm. From the measured signal, the TCS has shown the SNR of 44.0 dB, the nonlinearity of 0.59 % and the frequency-normalized sensitivity of $0.26{\pm}0.01{\;}V/T{\cdot}Hz$ in the temperature range of $-30{\sim}+43^{\circ}C$. Firing test has shown that the TCS can be used as a turn-counting sensor for small-caliber ammunition, verifying the shock survivability of TCS in high-g environments.

• ALGAE
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• 제20권2호
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• pp.121-125
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• 2005

The modern integrated fish-seaweed mariculture has been tested to reduce the environmental impacts of an intensive fed culture. To obtain the best seaweed bioremediation performance, the effects of therapeutants used for fish disease control on the selected seaweed species should be considered. As a selected seaweed, Porphyra yezoensis was tested with six commercial antibiotics including erythromycin thiocyanate_A, erythromycin thiocyanate_B, oxytetracycline, doxycycline, pefloxacin, and amoxicillin trihydrate under the batch incubation at a photon flux density of 10 $\mu$mol ${\cdot}m^{-2}\;{\cdot}\;s^{-1}$ at 15$^{\circ}C$. Among the tested commercial antibiotics, erythromycin thiocyanate_A, erythromycin thiocyanate_B, oxytetracycline, and doxycycline showed decreases in Fv/Fm, the photochemical efficiency of photosystem II, with a dose-dependant and time-dependant manner. From the quenching analysis of chlorophyll fluorescence, three differential patterns were observed in the antibiotics-treated Porphyra: (1) high nonphotochemical quenching (NPQ) and low photochemical quenching (qP) in the cases of Erythromycin thiocyanate_B and amoxicillin trihydrate, (2) high NPQ and high qP in the case of pefloxacin and (3) low NPQ and low qP in the case of oxytetracycline. These results indicated that antibiotics affected in various ways on the photosynthetic apparatus, reflecting differential lesion sites of antibiotics. In addition, the rates of ammonium uptake also decreased with a decrease of Fv/Fm in P. yezoensis thalli treated with erythromycin thiocyanate_B and oxytetracycline. Therefore, the four antibiotics mentioned could affect the bioremediation capacity of the selected seaweed species in the integrated fish-seaweed mariculture system due to the decrease of photosynthetic activity and the simultaneous decrease of ammonium uptake.

• 한국물환경학회지
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• 제29권2호
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• pp.247-258
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• 2013

A grid-based configuration of Land Surface Models (LSMs) coupled with a climate model can be advantageous in impact assessment of climate change for a large scale area. We assessed the applicability of Common Land Model (CoLM) to runoff and land surface temperature (LST) simulations at the domain that encompasses the Nakdong river basin. To establish a high resolution model configuration of a $1km{\times}1km$ grid size, both surface boundary condition and atmospheric inputs from the observed weather data in 2009 were adjusted to the same resolution. The Leaf Area Index (LAI) was collected from MODerate esolution Imaging Spectroradiometer (MODIS) and the downward short wave flux was produced by a nonstationary multi-site weather state model. Compared with the observed runoffs at the stations on Nakdong river, simulated runoffs properly responded to rainfall. The spatial features and the seasonal variations of the domain fairly well were captured in the simulated LSTs as well. The monthly and seasonal trend of LST were described well compared to the observations, however, the monthly averaged simulated LST exceeded the observed up to $2^{\circ}C$ at the 24 stations. From the results of our study, it is shown that high resolution LSMs can be used to evaluate not only quantity but also quality of water resources as it can capture the geographical features of the area of interest and its rainfall-runoff response.