• Journal of Environmental Science International
• /
• v.18 no.3
• /
• pp.255-261
• /
• 2009

We need water equivalent unit data of snowfall for the purpose of forecast and hydrology related research area. This study developed new method of automatic recording snowfall as weight unit. The instrument designed for measuring weight of snowfall by stain-gauge loadcell. Field test of instrument carried out at Daegwallyeong Obs. Station from 22 Jan. to 22 Feb. 2007. During observation period there is 15.3 cm snow depth and 16.0 mm of accumulated water equivalent depth at Daegwallyeong Obs. Station on 13 to 14 Feb. 2007. But the instrument of this study recorded 22.1 mm of water equivalent depth. It is not easy to explain difference between Daegwallyeong and this study. Because this study is only one case of comparison of snow measurement and there is very little amount of snow observation research. The density of snowfall calculated from 0.09 to $0.15g/cm^3$ from the observation data of 13 to 14 Feb. 2007. There is high relation between radar echo and snowfall amount measured by weight unit. It can supports forecast of snowfall and development of numerical model for forecast.

• Journal of the korean society of oceanography
• /
• v.34 no.4
• /
• pp.200-206
• /
• 1999

Seawater sampling is the primary task for the study of the marine environmental parameters that require shipboard or laboratory experiments for their analyses, and is also required for the calibration of some instruments for in situ measurement. A new automatic bottle (AUTTLE) is developed for seawater sampling at any desired time and water depth by self-triggering. Both any type of single or assembled mooring for 15 days and manual actuation by using a remote messenger as existing instantaneous single point water samplers are possible. Its sampling capacity and the resolution of time setting are 2 liters and 1 second, respectively. The result of a field experiment with an optical backscattering sensor (OBS) and a total of 14 AUTTLES for the in situ calibration of the OBS shows that the AUTTLE must improve our understanding on the behavior of the sand/mud mixtures in the environments with high waves and strong tides. The AUTTLE will serve as a valuable instrument in the various fields of oceanography, especially where synchronized seawater sampling at several sites is required and/or the information in storm period is important.

• Journal of the Korean Chemical Society
• /
• v.35 no.6
• /
• pp.653-658
• /
• 1991

The structural variation process and relation of water of amorphous Ta-IPA bulk and thin film upon heat-treatment conditions of $25^{\circ}C$ and $340^{\circ}C$ have been studied by using the radial distribution functions$ (RDF_{obs})$ estimated from the X-ray diffraction intensities, TG-DTA and Infrared spectrophotometer. The expected Ta-IPA structure was determined by comparing the $ RDF_{obs}$ with that for $RDF_{calc}$. The structure of specimens prepared by sol-gel method is basically based on the L-$Ta_2O_5$ crystal. Thin film of samples are mainly composed of octahedral Ta$O_6$and have smaller cluster than bulk samples.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2004.05b
• /
• pp.547-551
• /
• 2004

연안유역으로 유입되는 소하천의 유량 및 오염물질의 농도는 유역의 기상상태(강우량 및 증발량), 토지피복도, 인공구조물의 운영규clr 등에 의하여 변화한다. 특히, 강우에 의한 오염부하량 변화는 평상시의 오염부하량에 비하여 그 변화량이 매우 크기 때문에 평상시의 측정간격으로는 보다 정확한 오염부하량 산정에 한계가 있다. 따라서, 본 연구에서는 충청남도 보령시를 관통하는 대천천을 대상으로 강우에 의한 오염부하량 변화를 연속적으로 측정하였다. 대천천은 상류지역에 청천저수지가 형성되어 있으며, 보령시내를 관통하는 과정에서 도시 오염물질이 유입되는 양상을 보이고 있으며, 천수만 입구지역으로 유입되는 지방하천이다. 유역오염부하량 계산에 필요한 유량은 보(weir)에서 측정한 수위자료를 이용하여 환산하였으며, 수온, 탁도 및 염도는 OBS-3A 장비를 이용하여 연속측정하였다. 또한, 영양염류의 오염물질 농도는 30분 간격으로 채수하여 분석하였다. 분석결과, 오염물질 항목에 따라 시간에 따른 오염부하량 변화양상이 매우 상이하게 나타났으며, 변화 폭도 매우 크게 나타나서 강우시의 오염부하량을 추정하기 위해서는 1시간 간격 이내의 관측자료를 이용하여 추정하는 방법이 타당한 것으로 파악되었다.

• Journal of the Korean Chemical Society
• /
• v.37 no.1
• /
• pp.148-153
• /
• 1993

The Wallach rearrangement of 4'-halogenated azoxybenzenes in strong sulfuric acid was reinvestigated by UV-Vis spectrophotometric method. Interestingly an excellent linearity $(logk_{obs}=-0.61\;{\sigma}_R{^+} -3.29,\;{\gamma = 0.998)$ was obtained on plotting log (rate) vs. substituent constant, ${\sigma}_R{^+}$, which is known as the Pi delocalization parameter. Thus B-H mechanism via a charged intermediate $(DC^{++})$, which can be largely stabilized by resonance, is far more favored for the Wallach rearrangement.

• Journal of the Korean Chemical Society
• /
• v.34 no.1
• /
• pp.85-90
• /
• 1990

The inertness of eight-coordinate tetrakis(picolinato)tungsten(IV) complex has been investigated by spectroscopic method in nonpolar solvent at 60$^{\circ}C$, 75$^{\circ}C$, 90$^{\circ}C$, 120$^{\circ}C$, and reflux condition. Until 2 days, showed the inertness whether existance of oxygen or not. After 2 days, showed the oxidation of W(IV) complex much more rapidly than substitution, which had $k_{obs}(sec^{-1}) {\varpropto} 1/[ligand]^2$. On sealing the sample under Ar gas, showed the inertness until 50 days, which had $k_{obs}(sec^{-1}) = 8.8{\times} 10^{-7}$. The$^1H$-NMR peak of $H_6$ in complex was diminished, otherwise that of free ligand was grown up. This result indicated that this complex was very inert.

• Journal of the Korea Society of Computer and Information
• /
• v.24 no.2
• /
• pp.127-137
• /
• 2019

In this study, we have developed a calculation system for BIM-based quantities, 4D process, and 5D construction costs, by integrating object shape attributes and the standard classification system which consist of Cost Breakdown System(CBS), Object Breakdown System(OBS) and Work Breakdown System(WBS) in order to use for the 4 dimensional process control of roads and rivers. First, a new BIM library database connected with the BIM library shape objects was built according to the CBS/OBS/WBS standard classification system of the civil engineering field, and a integrated database system of BIM-based quantities, process(4D), and construction costs(5D) for roads and rivers was constructed. Nextly, the process classification system and the cost classification system were automatically disassembled to the BIM objects consisting of the Revit-family style elements. Finally, we added functions for automatically generating four dimensional activities and generating a automatic cost statement according to the combination of WBS and CBS classification system The ultimate goal of this study was to extend the integrated quantities, process(4D), and construction costs(5D) system for new roads and rivers, enabling the integrated use of process(4D) and construction costs(5D) in the design and construction stage, based on the tasks described above.

• Economic and Environmental Geology
• /
• v.44 no.3
• /
• pp.229-238
• /
• 2011

S-wave, which provides lithology and pore fluid information, plays a key role in estimating gas-hydrate saturation. In general, P- and S-wave velocities increase in the presence of gas-hydrate and the P-wave velocity decreases in the presence of free gas under the gas-hydrate layer. Whereas there are very small changes, even slightly increases, in the S-wave velocity in the free gas layer because S-wave is not affected by the pore fluid when propagating in the free gas layer. To verify those velocity properties of the BSR (bottom-simulating reflector) depth in the gas-hydrate prospect area in the Ulleung Basin, P- and S-wave velocity profiles were derived from multi-component ocean-bottom seismic data which were acquired by Korea Institute of Geoscience and Mineral Resources (KIGAM) in May 2009. OBS (ocean-bottom seismometer) hydrophone component data were modeled and inverted first through the traveltime inversion method to derive P-wave velocity and depth model of survey area. 2-D multichannel stacked data were incorporated as an initial model. Two horizontal geophone component data, then, were polarization filtered and rotated to make radial component section. Traveltimes of main S-wave events were picked and used for forward modeling incorporating Poisson's ratio. This modeling provides S-wave profiles and Poisson's ratio profiles at every OBS site. The results shows that P-wave velocities in most OBS sites decrease beneath the BSR, whereas S-wave velocities slightly increase. Consequently, Poisson's ratio decreased strongly beneath the BSR indicating the presence of a free gas layer under the BSR.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.19 no.6
• /
• pp.621-629
• /
• 2008

This paper presents a low temperature co-fire ceramics(LTCC) Upconverter for a Ka-band OBS satellite transponder in order for size reduction which is one of the most important requirement for satellite components. A S-band low-pass filter(LPF), a K-band band-pass filter(BPF), and an upconverting MMIC mixer are embedded in the multi-layer structure of the upconverter. All spurious can be selectively rejected by employing a modified Elliptic low pass filter with a multi-pole structure for the S-band LPF. Also an improved performance of out-of-band rejection can be obtained. At the K-band BPF design a layer coupled configuration is employed. The upconverting mixer is an MMIC diode mixer with a double-balanced configuration. Conversion loss and isolation of the upconverter are 9 dB and 51 dBc, respectively. The size of the LTCC upconverter is only $8{\times}7{\times}0.6mm^3$ which is one-third for the thin-film based upconverter.

• Geophysics and Geophysical Exploration
• /
• v.12 no.2
• /
• pp.173-182
• /
• 2009

In April 2008, KIGAM carried out an ocean-bottom seismometer (OBS) survey in the central Ulleung Basin where strong bottom simulating reflectors (BSRs) were revealed from previous surveys and some gas-hydrate samples were retrieved by direct sampling. The purpose of this survey is to estimate the velocity structure near the BSR in the gas hydrate prospect area using wide-angle seismic data recorded on the ocean-bottom seismometers. Along with the OBS survey, a 2-D seismic survey was performed whereby stratigraphic and preliminary velocity information was obtained. Two methods were applied to wide-angle data for estimating P wave velocity; one is velocity analysis in the $\tau$-p domain and the other is seismic traveltime inversion. A 1-D interval velocity profile was obtained by the first method, which was refined to layered velocity structure by the latter method. A layer stripping method was adopted for modeling and inversion. All velocity profiles at each OBS site clearly show velocity reversal at BSR depths due to the presence of gas hydrates. In addition, we could confirm high velocity in the column/chimney structure.