• The Journal of Engineering Geology
• /
• v.24 no.4
• /
• pp.631-641
• /
• 2014

Characteristics of water-level changes in the Temporary Gulpocheon Discharge Channel were identified by observing and analyzing changes in the subterranean water level induced by hydrological stresses the underground aquifer. The subterranean water level refers to the level at which the pressure of subterranean water passing through the corresponding position has an equipotential value that is in equilibrium with the atmospheric pressure at that location. This water level is not fixed but changes in response to hydrological stress. It can be identified by repeatedly measuring the distance from the observation point to the surface of the subterranean water. The subterranean water-level change equation and the variance range of the hydrological curve of subterranean water over 24 hours at the Gimpo-Gimpo National Groundwater Monitoring Network (NGMN) were used as assessment factors. The variance characteristics of the subterranean water at the 18 monitoring system locations were classified into three impact, observational wish, and non-impact. The impact type accounted for 50% of the subterranean water of and accurately reflected the water-level changes due to hydrological stress, showing that distance is the major controlling factor. The observational wish type accounted for 27.8% of the subterranean water, and one of the two assessment factors did not meet the assessment factors. The nonimpact type accounted for 22.2% of the subterranean water. This type satisfied the two assessment factors and represents subterranean water-level changes response to precipitation.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.3D
• /
• pp.283-289
• /
• 2012

Because railways themselves are not enough to provide door-to-door service, they need to be complemented by a transportation system access the stations and a convenient transfer system to access other railway lines. User friendly service policies include a faster, interconnected, and intermodal transportation system. It becomes more important to use deep subterranean space from an economical standpoint in order to promote railway construction projects. In this research, the authors dealt with construction plan for strengthening capacity of deep subterranean railways. Since deep subterranean railways are situated deeper underground than other railways, they are more difficult to access and transfer to, in addition to psychological pressure. Moreover, deep subterranean railways with high speed add access difficulties as the distance between stations increases. Therefore, the authors discuss not only systemization for uniting deep subterranean railways and other transportation facilities but also reinforcement strategies. The purpose of these strategies is so that deep subterranean railways provide mobility while established railways provide accessibility to overcome this problem.

• Proceedings of the SAREK Conference
• /
• 2007.11a
• /
• pp.612-617
• /
• 2007

Water meter frost in winter is a nuisance to the water administration and citizen as well. It causes stop of water supply, possibility of accident due to leakage freezing, and additional official work to change frost water meters. This study was carried out to give some basic information of water meter frost condition, to verify the effect of frost protection devices such as lagging vinyl cover, electric heater, and meter pit using subterranean heat. Nearly half of the number of the water meter frost happens in old apartment house with outer corridor, and temperature of the meter box was measured in that kind of apartment house, comparing with atmosphere temperature. The capability of three kinds of lagging vinyl cover was investigated by measuring the inside temperature of the insulated box. Also the capability of existing meter pits and new meter pits using subterranean heat was compared by measuring the inside temperature of the pits. One of the result is that the inside temperature of meter pits using subterranean heat was higher than that of the existing ones, and deeper pit causes higher inside temperature in case of using subterranean heat.

• Animal cells and systems
• /
• v.8 no.3
• /
• pp.145-154
• /
• 2004

Two freshwater cyclopoid species including a new species are added to Korean copepod fauna: Ochridacyclops coreensis n. sp. and Itocyclops yezoensis (Ito, 1953). Both species were collected from the semi-subterranean waters like springs and wells. The present paper deals with the description of the new species and the systematic accounts on the two species, based on the morphological character comparison with the related congeners.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.15 no.2
• /
• pp.80-86
• /
• 1995

High salinity common in reclaimed soil can reduce germination of crop seeds and aftermath its establishment and production. The experiment was done to measure germination and radicle elongation of berseem, subterranean, white clover and Italian ryegrass as Control under different temperature and NaCl concentrations. Onehundred seeds of berseem (Trifolium ulexandrinum cv. Bigbee). suberranean (T. suhterruneum, cv. Nungarin), white clover (T. repens, cv. Regal) and Italian ryegrass (Lolium mulriflorum, cv. Terafloum) were placed in petri dishes with a sheet of filter paper replaced every two days, and then exposed to 0, 12.5, 25. 50, 100 and 200mh4 of sodium chloride in darkened growth chambers controlled with 10, 15 and $20^{\circ}C$. Percent germination and radicle elongation were measured. Beneem clover showed greatest daily percent germination among the cloven. That of subterranean clover, moreover, was higher than that of white clover till 4 days after imbibition but the reverse result was true thereafter. Although germination of Italian ryegrass was delayed with decreased at 200mM of NaCl of $20^{\circ}C$. at 200mM of under$15^{\circ}C$ , and at higher than lOOmh4 of all level of temperature, respectively. Berseem clover had greatest radicle length under the same concentration of NaCl regardless of temperature treatment while radicle elongation of subterranean and white clover was repressed over 50-100mM of NaC1. The slope of linear regression equation between concentration of NaCl and percent germination declined under all temperature treatment in order of berseem, subterranean and white clover whereas the reverse result was showed in radicle length.

• The Journal of the Convergence on Culture Technology
• /
• v.9 no.2
• /
• pp.307-312
• /
• 2023

North Korea has already been using underground space for military purposes for decades, and is currently developing it as a key base for operating asymmetric forces. Accordingly, the special operations teams need fighting methods, weapon systems, and organizational structures to carry out subterranean operations. This paper presents an unmanned system platform for subterranean operations that combines tilt-rotor type drones, high-tech sensors, communication repeaters, and small robots, and a system that can be operated by special operation teams. Based on this, the survivability of the special operations teams can be strengthened and operational utility can be maximized. Afterwards, if Special Warfare Command collects collective intelligence based on the ideas related to subterranean operations presented in this paper and further develops these, it will be possible to drive subterranean operations doctrines, weapon systems, and organizational structures optimized for the battlefield on the Korean Theater of Operations in the near future.

• Journal of the Korean earth science society
• /
• v.32 no.1
• /
• pp.12-20
• /
• 2011

The gravity measurement was conducted at 256 stations around Chungju Lake to study subsurface geological distributions and subterranean mass discontinuities by the results of gravity anomaly in Metamorphic Complex, Okcheon Group, Great Limestone Group of Choson Supergroup, and Cretaceous biotite granites. Okcheon Group showed a high Bouguer gravity anomaly while Great Limestone Group of Choson Supergroup relatively a low anomaly. The mean depth of subterranean mass discontinuities is about 2.0 km and downward along the Suchangri Formation from the Hwanggangri and Moonjuri formations. In general, Okcheon Group appeared shallower than the depth of Great Limestone Group of Choson Supergroup when imaging the subterranean mass discontinuities from the Bouguer gravity anomaly.

• Explosives and Blasting
• /
• v.29 no.2
• /
• pp.32-42
• /
• 2011

For blasting vibration analysis, there are mostly two methods, firstly, far field vibration analysis to estimate limit of building damage, secondly, near field subterranean vibration analysis to estimate rock damage and subterranean structure facilities. The former has been mainly used in our country and aboard, the latter is mostly analysed by using Homberg's model. In this model, basic input data are acquired in far field surface vibration. But in the consideration of the results of being conducted in this area over the past few decade, it is required that Homberg's model is modified. For the purpose of this, measurements of near field vibration were first conducted in our country. But it was only proposed the measurement method and the method of analysis or prediction was not suggested. Accordingly, in this paper, measurements of near field subterranean vibration were conducted and the method of analysis or prediction of near field subterranean vibration would be suggested.

• Journal of the Korean Wood Science and Technology
• /
• v.46 no.6
• /
• pp.748-755
• /
• 2018

Timber from fast-growing tree species is susceptible to by biodeterioration attack, particularly subterranean termites. Impregnation with methyl methacrylate (MMA) potentially increases wood resistance to subterranean termite attack. Four wood species, namely sengon (Falcataria moluccana), jabon (Anthocephalus cadamba), mangium (Acacia mangium), and pine (Pinus merkusii), were impregnated with MMA, and samples of untreated and imidacloprid-preserved wood were prepared for comparison purposes. Small stakes, sized 0.8 cm by 2 cm in cross section by 20 cm in the longitudinal direction, were inserted into the ground for 3 months, and the weight loss of each specimen was determined at the end of the test period. A factorial $4{\times}3$ completely randomized design was used for data analysis; the first factor was wood species, and the second factor was treatment. The results showed that MMA polymer loadings were 27.88%, 24.91%, 14.14%, and 17.81% for sengon, jabon, mangium, and pine, respectively, and amounts of imidacloprid retention were $7.56kg/m^3$, $5.98kg/m^3$, $5.34kg/m^3$, and $9.53kg/m^3$, respectively. According to an analysis of variance, wood species, treatment, and interaction of both factors significantly affected the weight loss of wood specimens. Mangium had the smallest weight loss, followed by pine, sengon, and jabon. MMA impregnation into the wood increased the resistance of wood samples to subterranean termite attack during in-ground testing, but the resistance level was lower than that of imidacloprid-preserved wood. Except for mangium wood, the MMA treatment did not significantly affect resistance.

• Journal of the Korean Wood Science and Technology
• /
• v.48 no.1
• /
• pp.1-11
• /
• 2020

Indonesian log production is dominated by young trees harvested from plantation forests. The timber contains of sapwood and juvenile wood, which are not resistant to termite attack. Smoking treatment can enhance wood resistance to termite attack, but it also changes the color. Specimens of mangium (Acacia mangium) and sengon (Falcataria moluccana) wood were exposed for 1, 2, and 3 weeks to smoke produced from the pyrolysis of salam (Syzygium polyanthum) wood. The color change of the wood was measured using the CIELab method. In addition, wood specimens were exposed to subterranean termites (Coptotermes curvignathus Holmgren) under laboratory conditions. Untreated and imidacloprid-preserved wood samples were also prepared for comparison purposes. The results showed that the color of smoked wood differed from that of untreated wood, and the color change for sengon was greater than for mangium. In addition, the 1-week smoking period changed the wood color less than the 2- and 3-week periods, which did not differ. Imidacloprid-preserved wood had distinctive color changes compared to untreated wood. Untreated mangium wood had moderate resistance to subterranean termite attack (resistance class III), while sengon had very poor resistance (resistance class V). Salam wood smoke enhanced wood resistance to termite attack, and smoke treatment of 1 week for mangium and 2 weeks for sengon resulted in the wood becoming very resistant (resistance class I). Both types of smoked wood were more resistant to subterranean termite attack than imidacloprid-preserved wood (average class II resistance).