• 한국환경과학회지
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• 제19권1호
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• pp.81-87
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• 2010

Cool island intensity urban green space was investigated based in Dalsung Park, that is one of the largest parks in Daegu. Cool island intensity(CII), which is defined as the temperature difference between the green space and its surrounding built-up areas, shows time variations. A through-year measurement(2008-2009) of ground level air temperature revealed seasonal variation and relationship to the atmospheric condition of CII. The temperature variation in the park and the reference downtown Daegu was as same order as CII. The noontime CII is larger in summer than that in winter due to the leaf fall of the park trees. On the other hand, seasonal variation of nighttime CII is not so clear. The nighttime CII was larger under the stable atmosphere.

• Journal of Radiation Protection and Research
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• 제14권2호
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• pp.51-62
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• 1989

The high efficiency moderated-type neutron spectrometer and doseequivalent counter were developed for the measurement of low level environmental neutrons. By using these detectors, the neutron energy spectra and dose equivalent rates due to skyshine effect were measured in the environment surrounding the accelerator facilities and also the altitude variation of cosmic ray neutrons in the aircraft flying over Japan.

• 자원환경지질
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• 제28권1호
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• pp.25-31
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• 1995

동남 스카른 광상은 백악기에 고생대 퇴적암류를 관입한 섬록암에 의해 형성되었다. 스카른의 모암은 섬록암과 묘봉 슬레이트인데 스카른 누대구조에서 모암의 종류에 따라 각각 특징적인 광물공생군의 체계적 변화를 관찰할 수 있다. 섬록암, 화강반암, 석영반암으로 구성된 화성암류들은 플룸보텍토닉 모델의 조산대에 비해 높은$^{207}Pb/^{204}Pb$ 비를 보이는데 이러한 현상은 하부지각 (또는 맨틀)에서 유래된 마그마가 상부지각물질에 의해 심히 혼화되어진 것으로 해석되며 이는 영남육괴와 옥천계에 분포하는 화강암류가 보여주는 특징과 유사하다. 현재의 납 동위원소 비와 우라늄, 토륨, 납 농도로부터 구한 광화작용 당시(76 Ma)의 황성암 및 풍촌석회암의 납 동위원소 비는 비교적 일정하지만 광화작용 후기로 갈수록 광석광물들의 납 동위원소 비가 높아진다. 초생 스카른 시기에 형성된 자철석과 방연석의 납 동위원소 비는 화성암류의 것과 거의 유사하지만 후기 열수변질시기에 형성된 휘수연석, 황철석, 그리고 열수변질된 석영반암의 납 동위원소 비는 풍촌석회암의 비에 접근하고 있다. 이는 서로 다른 기원을 가진 납들이 열수 변질시기에 따라 그 혼화의 정도가 달라지게되어 광석광물들의 납 동위원소 비에 차이가 있게 된 것으로 여겨진다. 광석광물의 납 동위원소 비의 변화특징에 의하여 섬록암과 화강반암을 형성한 마그마로부터 분화된 낮은 납 동위원소 비를 갖는 열수용액과 높은 납 동위원소 비를 갖는 주변모암(풍촌석회암)이 혼화의 기원물질로 판단된다.

• 자원환경지질
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• 제26권4호
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• pp.465-472
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• 1993

The heavy metal contents are more abundant in stream waters, paddy soils and rice plants in the vicinity of abandoned mines compared to the surrounding areas in the Kyungpook province. However, these contents tend to decrease with distance from mines, and show some variation under different geological and geochemical environments. The Sin-stream waters have high contents of Cu=4.9 ppm, Pb=0.1 ppm, Zn=3.5 ppm and other heavy metals (Ni, Co, Cd) at Dalsung abandoned mine and low contents of Cu=0.4 ppm, Pb=0.1 ppm, Zn=0.1 ppm and other metals= 0.002 ppm in the surrounding area. The high contents decrease in the downstream in the area of calcareous sedimentary rocks. The paddy soils have high contents of approximately Cu=51 ppm, Pb=83 ppm, Zn=211 ppm, and Cd=11.3 ppm in the vicinity of Gunwi abandoned mine but low contents of Cu=4.5 ppm, Pb=2.9 ppm, Zn=60 ppm and Cd=0.4 ppm in the surrounding area. The Dadeog abandoned mine also shows similar trends to Gunwi mine. The contents of heavy metals of rice plants are high in the roots but trends to decrease through stem+leaf and become low in brown rices.

• 한국전기전자재료학회논문지
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• 제21권11호
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• pp.1010-1018
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• 2008

In this report, we describe the use of gold nanoparticles (AuNPs) immobilized on pH. responsive, cross-linked poly(4-vinylpyridine) (P4VP) thin films, as a potential application for pH nanosensors. The methodology is based on the variation in surface plasmon resonance of immobilized AuNPs with changing the interparticle distances, caused by the swelling/deswelling of the pH responsive P4VP polymer films. The change in optical properties of the immobilized AuNPs in response to the pH of surrounding media was investigated by a simple yet powerful tool; UV-vis absorption spectroscopy. The swelling of the P4VP chains at pH 2 causes an increase in the interparticle distances of immobilized AUNPS ($\sim20nm$) and hence leads to a blue shift of 48 nm in their surface plasmon resonance band peak. On the other hand, when the surrounding media was altered from pH 2 to 10, a red shift of absorption maxima was observed. The changes were rapid, and the effect was reversible. This system could prove to be useful in fabricating nanosensors for detecting the pH or pH changes of surrounding aqueous medium.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 추계학술대회
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• pp.251-254
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• 2018

주변 환경 변화에 따라 무선 수신 신호가 변화되는 현상을 활용한 Internet of Things(IoT) 시스템에 대한 연구가 활발히 진행되고 있다. 본 논문에서는 고정된 송수신기 간 주기적 신호 교환 시, 수신 신호가 주변 온도 변화에 따라 변화함을 증명하고, 수신 신호 변화를 활용한 화재 감지 기법을 제안한다. 제안 기법은 수신 신호 변화 감지부와 수신기 내부 온도 감지부로 구성되며, 수신기 내부 온도 감지부는 무선 채널 환경 변화에 따른 수신 신호 변화를 화재 발생으로 감지됨을 방지한다. 제안 기법은 화재 감지를 위해 별도의 장치 추가 없이 기존 수신기에 소프트웨어 개선을 통해 지원가능하다는 장점을 지닌다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1415-1426
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• 2008

Stone columns, locally called "GCP (granular compaction pile)" can be used to improve strength and resistance against lateral movement of a foundation soil like rigid piles and piers. Also installation of such a discrete column facilitates drainage, and densifies and reinforces the soil in the sense of ground improvement. The integrity of the GCP has been indirectly controlled with the records of each batch including depth and the quantity of stone filled. An integrity testing was attempted using crosshole S-wave logging. The method is conceptionally same as the crosshole sonic logging (CSL) for drilled piers. The only and critical difference is that S-wave should be used in the logging, because P-wave velocity of the stone column is less than that of ground water. The crosshole sonic logger does not have the capability to measure S-wave propagating through the skeleton of crushed stone. An electro-mechanical source, which can generate either P- or SH-waves, and a 1-D geophone were used to measure SH-waves. Two 76mm diameter cased boreholes were installed 1 meter apart across the nominal 700mm diameter stone column. At every 10cm of depth, shear wave was measured across the stone column. One more borehole was also installed 1 meter outward from the one of the above boreholes to measure the shear wave profile of the surrounding soil. The diametric variation of the stone column with respect to depth was evaluated from the shear wave arrival times across the stone column, and shear wave velocities of crushed stone and surrounding soil. The volume calculated with these variational diameters is very close to the actual quantity of the stone filled.

• 한국연소학회지
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• 제4권1호
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• pp.17-26
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• 1999

Vaporization, ignition and combustion of fuel droplets in tandem array are theoretically investigated to understand the droplet interactions in combustors. Including the effects of density variation in gas-phase, internal circulation and transient liquid heating, a numerical studies are performed by changing parameters such as initial droplet temperatures, initial droplet spacings, initial Reynolds numbers, surrounding gas temperatures, and activation energies of fuel vapors. Combustion regime maps classify the droplet combustion phenomena according to the configuration and location of the flame with respect to injection Reynolds numbers and surrounding gas temperatures. In addition, it is shown that the dynamic histories of droplets and ignition delay times are dependent on droplet size ratios and initial spacings of tandem droplets.

• 자동차안전학회지
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• 제15권2호
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• pp.21-27
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• 2023

This paper presents a simulation tool for developing and evaluating automated driving systems' lane change algorithm in urban congested traffic. The behavior of surrounding vehicles was modeled based on driver driving data measured in urban congested traffic. Surrounding vehicles are divided into aggressive vehicles and non-aggressive vehicles. The degree of aggressiveness is determined according to the lateral position to initiate interaction with the vehicle in the next lane. In addition, the desired velocity and desired time gap of each vehicle are all randomly assigned. The simulation was conducted by reflecting the cognitive limitations and control performance of the autonomous vehicle. It was possible to confirm the change in the lane change performance according to the variation of the lane change decision algorithm.

• 한국산림과학회지
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• 제99권2호
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• pp.235-243
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• 2010

Picea jezoensis with several infraspecific taxa is indigenous to Eastern Asia and the Far East of Russia. Although these taxa are very common, the taxonomic confusion surrounding this complex is reflected in ambiguity of the various taxonomic treatments currently used. Patterns of intraspecific variations of cone morphology and recognition of taxa within the P. jezoensis complex were investigated from 175 individuals. Morphological variation of cone characters was determined by the univariate analysis to be insignificant in separating most previously recognized infraspecific taxa in Korea, China, Russia, and Japan. Our statistical analysis showed that cones from northern populations were larger and wider than those from southern populations. Individuals from South Korea were predominantly smaller even than those from Honshu of Japan which were previously recognized as var. hondoensis. All measured characters appeared to show some clinal variation with changes in latitude, and a distinctive trend was evident. Consequently var. hondoensis, var. koreana, and var. microsperma cannot retain their infraspecific state within the P. jezoensis complex.