• The Korean Journal of Zoology
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• v.23 no.4
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• pp.203-218
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• 1980

Unscheduled DNA synthesis, chromosome aberrations, sister chromatid exchanges and DNA replication inhibition induced by the combined treatments with ara-C and UV-light or MMS in $HF_1$, CHO and $HelaS_3$ cells were studied, and the results obtained were as follows: (1) Ara-C was found to inhibit UV-or MMS-induced unscheduled DNA synthesis and the inhibitory effect of ara-C was more remarkable in its post-treatment. (2) Ara-C enhanced the rate of chromosome aberrations induced by MMS or UV-light. Post-treatment with ara-C exhibited the synergistic effect on MMS-induced chromosome aberrations mainly by increases of chromatid deletions. (3) Contrarily, ara-C did not increase the rate of sister chromatid exchanges, particularly in the pre-treatment with MMS, although it was found to induce sister chromatid exchanges. (4) The rate of DNA synthesis was declined immediately after are-C treatment and then recovered. The combined treatments with ara-C and UV-light or MMS showed that the initial response on replication inhibition was similar to that of ara-C, but later responses were similar to that of UV-light or MMS treated group.

• Korean Journal of Plant Taxonomy
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• v.33 no.4
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• pp.339-357
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• 2003

The general morphological characters and chromosome numbers about 7 taxa of Korean Allium sect. Sacculiferum were reviewed. From the results, authors elucidated the key character as well as the range of variations in each taxon, and considered the relationships among taxa in this section. Clear taxonomic treatments also carried out based on the type specimens and the original descriptions. Shape and growing pattern of leaves, size of inflorescences, shape of perianths and tepals, as well as chromosome numbers were key characters in identifying the taxa and in estimating their relationships. On the basis of these characters, A. thunbergii var. thunbergii, A. sacculiferum and A. deltoide-fistulosum were recognised as a distinct species respectively. Hal-la-bu-chu which had been misidentified as A. cyaneum (sect. Reticulato-bulbosa) in Korea was proved to be A. taquetii and belonged to the sect. Sacculi/erum. In addition, A. cyaneum var. deltoides, had been described as a variety of A. cyaneum, was recombined as a variety of A. thunbergii [A. thunbergii var. deltoides (S. Yu, W. Lee et S. Lee) H. J. Choi et B. U. Oh] with the new Korean name of 'Se-mo-san-bu-chu'. In conclusion, Korean sect. Sacculiferum was composed of five species and two varieties. A key to identify the taxa in this section was provided.

• Journal of the Korean earth science society
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• v.23 no.4
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• pp.369-379
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• 2002

The characteristics of the East Asian summer monsoon circulation associated with the cool and wet summer of 1993 and the warm and dry summer of 1994 are investigated by analyzing the atmospheric circulations features in the upper and lower troposphere and by examining the global SST and associated tropical convective precipitation fields. The negative geopotential height anomalies at 500 hPa and 200 hPa in 1993 over East Asia, the central North Pacific, and the western United States were replaced by positive ones in 1994. In addition, the 200 hPa zonal wind anomaly averaged over the East Asian summer monsoon region is negatively correlated with the Korean summer temperature anomaly. The subtropical jet stream in 1993 was displaced into the central part of Korea well south of its normal position. The western Pacific subtropical high was shifted southward, and the East Asian summer rainfall and temperature was above-normal and below-normal, respectively due to the southwestward extension of a cold and dry polar airmass from the Sea of Okhotsk to the Est Sea. In contrast, the subtropical jet stream in 1994 was displaced well north of its normal position. The abrupt northward shift of the western Pacific subtropical high was accompanied with the rapid northward movement of the rain band of the East Asian summer monsoon rainfall. The anomaly patterns of the East Asia summer rainfall and temperature were opposite to those of 1993. Large sea surface temperature anomalies of opposite signs existed in the tropical Pacific with a mature El $Ni{\~{n}o$ in 1993 and a weak La $Ni{\~{n}a$ condition in 1994. The role of the anomalous convective precipitation in the western Pacific and the Indian Ocean related with the variations in the low-level cross-equatorial flow along the northwestern periphery of the Australian high and the Mascarene high is probably to influence a large-scale atmospheric circulation over the East Asia during both the years.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.8
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• pp.1107-1113
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• 2018

Ultrasonography and photodynamic therapy have been proposed as useful tools as a treatment for inducing necrosis of cells using reactive oxygen species. Apoptosis is an internal mechanism necessary for cells regardless of damage. Ultrasound has the effect of inducing the apoptosis of these cells, and the frequency of 1 MHz is the most applicable area for medical use. The laser which is generally used in photodynamic therapy has a heat reaction and the treatment is limited. However, as a small light emitting diode is developed, it shows possibility to minimize the equipment and reduce heat reaction. On the other hand, there are relatively few researches on direct effects of light compared with studies using photosensitizers, and the area is also limited. Therefore, in this paper, we have developed a cancer cell proliferation control module using ultrasonic and light emitting diodes, which have relatively few side effects, and quantitatively analyze the effect of the module to propose an optimal suppression technique.

• The Journal of the Petrological Society of Korea
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• v.26 no.2
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• pp.113-125
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• 2017

We investigates geochemical and tectonic characteristics for the Triassic Bojangsan trachyte in the southern margin of the Imjingang belt. The geochemical signatures of the thracyte are characterized by enrichments of REE and HFS, and show no Nb trough, suggesting that would not experience arc magmatic processes involving continental crustal materials. The trachyte reveals within-plate setting in tectonic discrimination diagrams using immobile HFS Nb and Y elements. And the trachyte shows typical signatures of A-type volcanic rocks with high Ga abundance and is classified as A1-type volcanic rocks rich in Nb. The geochemical signatures suggest that the trachyte was produced by the differentiation of mantle-derived magmatism at the continental rift in extensional setting subsequent to a major collision during the Permo-Triassic Songrim orogeny. The results provide robust evodence to consider the Imjingang belt as an extension of the the Qinling-Dabie-Sulu belt between the North and South China blocks.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.91-101
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• 2000

The emission sources of volatile organic compounds (VOCs) are wastewater treatment plants. sanitary landfills, automobile industries, and so on. The VOCs are harmful to human beings because of their toxicity and carcinogenicity, and cause the serious air pollution problem producing ozone ($O_3$) as a result of photochemical reaction. To investigate the emission of VOCs from wastewater treatment plant, aeration basins at the City of Los Angeles' Hyperion Treatment Plant were selected and measured flux was compared with calculated flux. For compounds commonly associated with wastewater (DCM, TCM, PCE, UM, DCB, UND) and not expected in vehicle exhaust or ambient air coming off the ocean, concentrations immediately downwind of the aeration basins were a factor of ten or higher than those measured in the upwind air. The airborne flux of less degradable or non-biodegradable compounds, e.g., DCE, DCM, TCA, DCA, TCM, PCE, DCB, through an imaginary plane at the downwind side of the aeration basins was in agreement with the estimated flux from measured liquid phase concentrations. Henry's constant. aeration rate, and an assumption of bubble saturation. For several compounds (PCE, DCE, TCA), the ratio (measured flux/calculated flux) is almost unity.

• Journal of Wetlands Research
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• v.20 no.1
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• pp.43-53
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• 2018

Laguna Lake is the largest inland fresh water body in the Philippines. It primarily serves as a site for aquaculture, hydropower, transportation, and water supply industries. Due to Laguna Lake's diverse functionalities, competition among water users became prominent. Water quality began to deteriorate due to various pollutant contributions in this process, thereby affecting the soundness of the aquatic ecosystem. This study was conducted to evaluate the current water quality management policy from the viewpoint of ecological environment through the evaluation of the water quality of Laguna Lake. Concentrations of water pollutants such as ammonia ($NH_3$), biochemical oxygen demand (BOD), chloride ($Cl^-$), pH, and total suspended solids (TSS) exceeded the water quality standards of the Philippines' Department of Environment and Natural Resources (DENR). The water quality of the lake was also affected by the pollutant load due to agriculture and urban stormwater runoff in the watershed. The salinity and contaminated water from Pasig River also affected the water quality of Laguna Lake. Long-term water quality analysis showed that the water quality of Laguna Lake is also influenced by rainfall-related seasonal variations. The results of the water quality analysis of Laguna Lake indicated that the environmental management techniques of the Philippines should be changed from the conventional water management into an integrated watershed management scheme in the future. It is therefore necessary to study and introduce advanced watershed management measures in the Philippines based from the policies of other developed countries.

• Korean Journal of Materials Research
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• v.3 no.3
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• pp.261-271
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• 1993

Functionally Gradient Materials(FGM) of 4.5Pb($Ni_{1/3}Nb_{2/3})O_3$-55PZT and PLZT(lO/70 /30, 11/60/40) were prepared. Its dielectric and piezoelectric strain properties were investigated. The FGM were pressed into A/B/ A configuration using two kinds of films, one layer(A) was eliminated from FGM by polishing after sintering at $l250^{\circ}C$, 2 hrs. The acrylic binder system was successfully applied for crack free film through doctor blade method. The thickness of gradent layer in FGM was about 30${\mu}$m. Dielectric properties of FGM show the average value of each side layer. The strain-electric field characteristics of FGM were significantly improved comparison with the other single compositions. The prepared FGM piezoelectric actuator shows about 3${\mu}$m/IOOV displacement.

• The Journal of the Acoustical Society of Korea
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• v.28 no.3
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• pp.198-207
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• 2009

Distribution of cavitation bubbles relative to change of the sound speed and attenuation in the water was estimated using acoustic signal from 20 to 300 kHz in two cases that cavitation bubbles exist and do not exist. To study generation and extinction property of cavitation bubble, bubble distribution was estimated in three cases: change of rotation speed (3000-4000 rpm), surface area of blade ($32-98\;mm^2$) and elapsed time (30-120 sec). As a result, the radii of the generated bubbles ranged from 10 to $60{\mu}m$, and bubble radius of $10-20{\mu}m$ and $20-30{\mu}m$ was accounted for 45 and 25% of the total number of cavitation bubbles, respectively. And generation bubble population correlated closely with the rotating speed of the blades but did not correlate with the surface area of blade. It was observed that 80% of total bubble population disappeared within 2 minutes. Finally, acoustic data of bubble distribution was compared with optical data.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.2
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• pp.117-125
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• 2000

The waveform and spectrum analysis of Tursiops truncatus(bottlenose dolphin) sonar signals were carried out on the basis of data collected during the dolphin show at the aquarium of Cheju Pacificland from October 1998 to February 1999. When greeting to audience, the pulse width, peak frequency and spectrum level from the five dolphins'sonar signals were 3.0ms, 4.54kHz and 125.6dB, respectively. At the time of warm-up just before the show, their figures were 5.0㎳, 5.24kHz and 127.0dB, respectively. During the performance of dolphins, with singing, peak frequency ranged 3.28∼5.78kHz and spectrum level ranged 137.0∼142.0dB. With playing ring, pulse width, peak frequency and spectrum level were 7.0㎳, 2.54kHz and 135.9dB, and when playing the ball, the values were 9.0㎳, 2.78kHz and 135.2dB, respectively. The values determined from the five dolphins during jump-up out of water were : pulse width 2.0㎳, peak frequency 4.50kHz and spectrum level 126.8dB. When they responded to trainer's instructions, the values were 2.25㎳, 248kHz and 148.7dB, respectively, and greeting to audience, the peak frequency and spectrum level were 5.84kHz and 122.5dB. During swimming under water, peak frequency and spectrum level were determined to be 10.10kHz and 126.8dB. It was found that there exited close consistencies in pulse width, frequency distribution and spectrum level between whistle sounds and dolphin's sonar signals. Accordingly, the dolphins can be easily trained by using whistle sound based on the results obtained from the waveform and spectrum of the dolphin's sonar signals.