• Journal of Ecology and Environment
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• 제39권1호
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• pp.43-49
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• 2016

Fishways are constructed to provide longitudinal connectivity of streams or rivers where their flow has been altered by in-stream structures such as dams or weirs. Nature-like fishways have an additional function of providing fish habitats. In the study, we estimated the role of a nature-like fishway (length: 700 m, slope: 1/100) for fish habitat by using two dominant species in the Sangju Weir, Nakdong River, to calculate the optimal ecological flow rate using Physical HABitat SIMulation (PHABSIM). To identify the dominant species that used the fishway, we conducted trap monitoring from August to November 2012 at the fishway exit. The dominant species were Zacco platypus and Opsariichthys uncirostric amurensis with a relative abundance of 62.1% and 35.9%, respectively. Optimal habitat suitability indices (HSIs) for Z. platypus and O. u. amurensis were calculated as 0.6-0.8 m/s (water velocity) and 0.2-0.4 m (water depth), and 0.5-0.7 m/s (water velocity) and 0.1-0.3 m (water depth), respectively. The optimal ecological flow rates (OEFs) for Z. platypus and O. u. amurensis were 1.6 and 1.7 cubic meter per second (CMS), respectively. The results of the study can be used in a management plan to increase the habitat function of nature-like fishways in the Sangju Weir. This methodology can be utilized as an appropriate tool that can determine the habitat function of all nature-like fishways.

• 한국자기공명학회논문지
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• 제22권2호
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• pp.26-33
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• 2018

Xanthium sibiricum is used as a traditional folk medicine for the treatment of cancer, fever, headache, nasal sinusitis, and skin pruritus. This study aimed to identify components from Xanthium sibiricum extracts using an SPE-800MHz NMR-MS hyphenated system. The simultaneous acquisition of MS and NMR spectra from the same chromatographic peaks significantly increases the depth of information acquired for the compound and allows the elucidation of structures that would not be possible using MS or NMR data alone. LC -NMR analysis was conducted using a HPLC separation system coupled to 800 MHz spectrometer equipped with a cryoprobe, and a SPE unit was used to automatically trap chromatographic peaks using a HPLC pump. LC-MS analysis was conducted with a Q-TOF MS instrument using ESI ionization in the negative ion mode. Using the hyphenated analysis, several secondary metabolites were identified, such as 3',5'-O-dicaffeoylquinic acid, 1',5'-O-dicaffeoyl- quinic acid, and ethyl caffeate. These results demonstrate that the SPE-800MHz NMR-MS hyphenated system can be used to identify metabolites within natural products that have complex mixtures.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권1호
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• pp.24-29
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• 2000

We propose a simple method to control the crystallization depth of amorphous silicon (a-Si) deposited by PECVD or LPCVD during the excimer laser annealing (ELA). Employing the new method, we have formed poly-Si/a-Si double film and fabricated a new poly-Si TFT with vertical a-Si offsets between the poly-Si channel and the source/drain of TFT without any additional photo-lithography process. The maximum leakage current of the new poly-Si TFT decreased about 80% due to the highly resistive vertical a-Si offsets which reduce the peak electric field in drain depletion region and suppress electron-hole pair generation. In ON state, current flows spreading down through broad a-Si cross-section in the vertical a-Si offsets and the current density in the drain depletion region where large electric field is applied is reduced. The stability of poly-Si TFT has been improved noticeably by suppressing trap state generation in drain region which is caused by high current density and large electric field. For example, ON current of the new TFT decreased only 7% at a stress condition where ON current of conventional TFT decreased 89%.

• Journal of Radiation Protection and Research
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• 제7권1호
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• pp.49-55
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• 1982

유기중합체의 열자극전류는 방사선량측정기로서 사용가능한 특성을 갖고있으며 중합체의 구성성분이 생체조직과 등가성분이므로 의학 및 생물학분야에서 효과적인 방사선 측정기구로 이용할 수 있었다. 포리에틸렌등 중합체에 방사선을 조사한후 $10{\sim}100V$의 전압과 실온에서 $100^{\circ}C$까지의 온도에 따라 열자극 전류를 측정하고 분석함으로서 물질의 에너지상수($0.8{\sim}1.0eV$)와 방사선피폭량(수Krands)에 따른 열자극전류($10^{-2}{\sim}10^{-4}{\mu}A$)의 상호관계를 계측할 수 있었다.

• 한국수산과학회지
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• 제10권1호
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• pp.49-52
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• 1977

1. 자리돔 들망에서 18과, 28속, 35종이 채집되었다. 낚이는 것과 저자망에 걸리는 것을 합하면 40종이상은 된다. 2. 어종으로서는 놀래기과 Labridae가 6종으로 가장 많았다. 3. 어획량으로서는 자리돔 Chromis natatus이 $90\%$이상이지만 줄도화돔 Apogon semilineatus과 놀래기류도 비교적 많이 어획되고 있다. 4. 자리돔 Chromis notatus은 수심 $15\~25m$ 수역에서 어획되고 있다. 5. 비식용의 관상용어종, 희귀종, 아열대성어류가 서기포연안일대에서 채집된다. 6. 다음 3종은 한국미기록종이다. Chromis analis, Franzia cheirospilos, Fugu exascurus.

• 한국기계가공학회지
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• 제19권5호
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• pp.82-90
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• 2020

Due to the complicated shape of the spider, the production method was changed from cold to warm forging. Finite element analysis was performed to predict the forging load and shape using the enclosed hydraulic die set. As the forging load increases due to the spider die volume, die stress analyses were performed to optimize the die design in order to reduce the die stress in various conditions. Large deformation while producing the complicated forging parts induces high forging load, which is one of the main parameters of the forging surface defects. The forging process was analyzed to find out the root cause of the surface defects generated during the spider production for various parameters, thereby revealing that the radius of die in the defect zone influenced the air trap depth, being the root cause of the surface defect. It was verified that die life was increased and the surface defect was eliminated by changing the die design during the mass production test.

• 한국수산과학회지
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• 제39권spc1호
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• pp.223-230
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• 2006

We investigated the spring and summer community structure of meiobenthos in a tidal-falt near Iwon, Korea, in 2002 and 2003. In total, 12 meiofaunal groups were found in the study area among which nematodes were the most dominant. Benthic foraminiferans, harpacticoid copepods, polychaetes, and crustacean nauplli were also dominant groups at all sites. The total density of meiobenthos at each station was be 246-2,177 ind./$10cm^2$. As the depth of sediment increased, the density of meiobenthos at each station gradually decreased. Changes in the vertical distribution of meiobenthos in the study area occurred mainly near the sediment surface (0-1 cm). Generally, between spring and summer the density of nematodes increased, and the density of other dominant meiofaunal groups (benthic harpacticoids, crustacean nauplii, benthic foraminiferans) decreased near the sediment trap the control site of sediment traps compared to that at the control site. The results of cluster and multidimensional scaling plots indicate that the meiofaunal community changed following construction of a low artificial wood groin structure.

• 한국환경복원기술학회지
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• 제7권1호
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• pp.97-109
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• 2004

The disposal of stormwater is one of the major problems in urban water management. One method of reducing peak runoff rates and other detrimental impacts of stormwater is detention storage. Detention ponds as a water quality control alternatives have been investigated by a number of researchers. Recognizing multiple roles such as flood peak attenuation, pollution removal and aesthetic enhancement, the design and management of detentions ponds deserve more research. The purpose of this research is to establish design criteria wet detention ponds to improve water quality. Water quality in detention pond discharge might be improve with physical, chemical and biological alterations. Physical alteration was focused in this study. There are several methods for estimating the suspended solid control capability of wet detention ponds. Existing models of suspended solids removal are based on sedimentation and gravity settling theory. The pollutant trap efficiency of pond is a function of several interrelating factors. Detention time is the most important factor, because it determine gravity settling quantities of pollutants. Desirable modification of physical factors for improvement of water quality in wet detention ponds are volume ratio, area ratio, length to width ratio, depth, out let location, bottom soil type. In order to apply design procedure in actual site, Namak new town development area was selected.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.229-229
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• 2011

부유 게이트 Floating gate (FG) 플래시 메모리 소자의 단점을 개선하기 위해 전하 포획 층에 전하를 저장하는 전하 포획 플래시 메모리 Charge trap flash (CTF)소자에 대한 연구가 활발히 진행되고 있다. CTF소자는 FG플래시 메모리 소자에 비해 비례축소가 용이하고 긴 retention time을 가지며, 낮은 구동 전압을 사용하는 장점을 가지고 있다. CTF 소자에서 비례축소에 따라 단채널 효과와 펀치-쓰루 현상이 증가하는 문제점이 있다.본 연구에서는 CTF 단채널 효과와 펀치-쓰루 현상을 감소시키기 위한 방법으로 silicon-on-insulator (SOI) 기판을 사용하였으며 SOI기판에서 절연층의 깊이에 따른 전기적 특성을 고찰하였다. silicon-oxide-nitride-oxide-silicon(SONOS) 구조를 가진 CTF 메모리 소자를 사용하여 절연층의 깊이 변화에 따른 subthreshold swing특성, 쓰기-지우기 동작 특성을 TCAD 시뮬레이션 툴인 Sentaurus를 사용하여 조사하였다. 소스와 드레인의 junction depth는 20 nm 사용하였고, 절연층의 깊이는 5 nm~25 nm까지 변화하면서 절연층의 깊이가 20 nm이하인 fully depletion 소자에 비해, 절연층의 깊이가 25 nm인 소자는 partially depletion으로 인해서 드레인 전류 레벨이 낮아지고 subthreshold swing값이 증가하는 현상이 나타났다. 절연층의 깊이가 너무 얕을 경우, 채널 형성의 어려움으로 인해 subthreshold swing과 드레인 전류 레벨의 전기적성질이 SOI기판을 사용하지 않았을 경우보다 떨어지는 경향을 보였다. 절연층의 깊이가 17.5 nm인 경우, CTF소자의 subthreshold swing과 드레인 전류 레벨이 가장 좋은 특성을 보였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.37-40
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• 1999

For the first time, charge trapping nonvolatile semiconductor memories with the deoxidized oxynitride gate dielectric is proposed and demonstrated. Gate dielectric wit thickness of less than 1 nm have been grown by postnitridation of pregrown thermal silicon oxides in NO ambient and then reoxidation. The nitrogen distribution and chemical state due to NO anneal/reoxidation were investigated by M-SIMS, TOF-SIMS, AES depth profiles. When the NO anneal oxynitride film was reoxidized on the nitride film, the nitrogen at initial oxide interface not only moved toward initial oxide interface, but also diffused through the newly formed tunnel oxide by exchange for oxygen. The results of reoxidized oxynitride(ONO) film analysis exhibits that it is made up of SiO$_2$(blocking oxide)/N-rich SiON interface/Si-rich SiON(nitrogen diffused tunnel oxide)/Si substrate. In addition, the SiON and the S1$_2$NO Phase is distributed mainly near the tunnel oxide, and SiN phase is distributed mainly at tunnel oxide/Si substrate interface.