• Proceedings of the KSEE Conference
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• 2008.04a
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• pp.21-31
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• 2008

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.51-51
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• 2003

대농갱이는 체형이 동자개와 비슷하나 지금까지 인공부화는 물론 산란습성에 관해서도 잘 알려져 있지 않은 미개발 어종으로 양식품종의 다양화 및 경쟁력 있는 새로운 품종 개발을 위하여 인공종묘생산 시험을 시도하였다. 본 연구에 사용한 대농갱이 친어는 금강 중류역에서 서식하고 있는 자연산 친어로 암컷 210마리, 수컷 148마리를 사용하였다. 호르몬주사에 의한 인공 배란효과 조사를 위해 암컷 한 마리당 HCG 1,000 IU 주사군(75마리)과 2,000 IU 주사군(135마리)으로 나누어 배란율을 조사하였으며, 수컷은 주사하지 않고 정소를 적출하여 막자사발에 갈아서 등조액과 혼합하여 사용했다. 수정 방법은 난을 착출하면서 정자 등조액을 동시에 흘리는 방법, 난을 그릇에 받은 후 정자 등조액을 혼합 수정하는 방법, 채란용기에 정자 등조액을 미리 넣고 암컷의 난을 짜 넣어 수정시키는 방법 등 3가지 방법을 사용하였다. 부화된 자어는 초기먹이로 알테미아(3일 급이), 실지렁이(6일 급이), 배합사료 순으로 급이하였으며 수온 25~28$^{\circ}C$에 유지관리하면서 성장도 시험을 실시하였다. 호르몬 주사에 의한 배란효과는 HCG 2,000 IU 주사군(채란율 88.9%)이 1,000 IU 주사군(37.3%)에 비해 월등히 높았으며 난의 성숙상태도 좋았다. 수정방법에 있어서는 채란과 동시에 정자 등조액을 흘려 수정시키는 방법과 채란용기에 미리 정자 등조액을 넣고 암컷의 난을 한 마리씩 짜서 수정한 후 바로 부화지로 이동하여 고르게 뿌려 준 경우가 수정율 및 부화율이 좋았다. 부화수온은 23$\pm$1$^{\circ}C$에서 96시간, 26$\pm$1$^{\circ}C$에서는 72시간만에 부화되었으며 부화여건이 좋으면 단시간에 부화할 수 있도록 하는 것이 수생균 발생을 억제할 수 있어서 효과적이었다. 자치어의 성장도 실험에서는 사육수온 25~28$^{\circ}C$에서 직선식으로 나타낼 수 있어서 평균체장은 Y=0.9943X+0.7867, 평균체중은 Y=0.8800-0.6800로 각각 표시되었다.

• Korean Journal of Ichthyology
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• v.28 no.1
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• pp.57-64
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• 2016

The fish species Uraspis helvola and U. uraspis (family Carangidae, Perciformes) were collected from Korea, and described and compared based on morphological and molecular characters. Uraspis helvola and U. uraspis were clearly distinguished by differences in the beginning point of the straight lateral lines scales (dorsal fin soft rays 12th~13th in U. helvola vs. 15th~16th in U. uraspis), and in the naked area on the breast extends to the pectoral fin base (naked area half way in U. helvola vs. naked area widely connected in U. uraspis). Molecular analysis using 530 base-pairs of mitochondrial DNA cytochrome c oxidase subunit I gene strongly supported the morphological identification. We described it as the new Korean record, and proposed the new Korean name "min-jeon-gaeng-i-sok" for the genus Uraspis, and "heuk-gi-min-jeon-gaeng-i" for the species U. uraspis.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.1
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• pp.49-62
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• 2007

A new earth pressure equation acting on the vertical shafts in cohesionless soils has been proposed by modifying the equations proposed by others. In order to verify the modified equation, model tests which can control uniform wall displacement with depth to radial direction were conducted. Model tests were performed with three different wall friction angles and two different relative densities. The measured values were larger than estimated values when assuming $\lambda=1$ ; smaller than those when assuming $\lambda=1-sin\phi$. The parameter, $\lambda$ is the ratio of tangential stress to vertical stress and is the most critical value in proposed equation. A method which can estimate the earth pressure on vertical shafts in layered soils is also proposed by reasonably assuming the failure surface of layered soils and using the modified equation. In order to verify the proposed method, in-situ measurement data have been collected from the three in-situ vertical shafts installed in layered soils. Most of earth pressures converted from measured data match reasonably well with estimated values using proposed method.

• Journal of Aquaculture
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• v.22 no.1
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• pp.74-78
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• 2009

Backcross hybridization between Korean bullhead Pseudobagrus fulvidraco female and Korean bullhead P. fulvidraco $\times$ Ussurian bullhead Leiocassis ussuriensis hybrid male was performed, and early viability and karyotype of the backcross hybrids were examined along with their parental species. Mean fertilization rate (86.8%), hatching success (70.7%) and early survival rate (76.4%) of backcross hybrids were similar with those found in the maternal species, the Korean bullhead. From the chromosome analysis, modal chromosome numbers of Korean bullhead, Ussurian bullhead, their hybrid and backcross hybrid were the same as 2n = 52. However, their karyotypes were different among genotypes. The karyotype of backcross hybrid was 22 metacentric + 18 submetacentacentric + 12 acrocentric chromosomes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1461-1468
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• 2015

Mostly mine support(Rock bolt and Support) which is currently general for reinforcements of a large scale tunnel is applied, Some executing a reinforcement to Poor ground by cast-in-place shotcrete. However On domestic mine conditions that couldn't having every time after mine tunnel excavation, it couldn't ensure the field batch plant which is a fixed in an issue of economies and site security, constructing it by supply gets from shotcrete materials combined in neighborhood ready mixed concrete manufacturing plants. carried shotcrete in ready mixed concrete manufacturing plants as migration length and time are falling off in quality. But, it is difficult for construction quality control By quality control arbitrariness absence at on-scene. In the present study, carry out Laboratory Test by kinds and percentages of accelerating agent for evalution of Mechanical Property and Durability of Shotcrete.

• Tunnel and Underground Space
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• v.30 no.6
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• pp.519-539
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• 2020

We reviewed numerical approaches to assess a hydraulic properties of excavation-disturbed zone (EDZ)created in argillaceous sedimentary rocks. It has been reported that fractures in the sedimentary rocks containing expansive clays are gradually closing due to swelling and their permeabilities are evolving to the level of in-tact rock, which is known as a self-healing or self-sealing process. The numerical approaches introduced here are capable of simulating spatio-temporal variation of EDZ permeability during long-term operation of a repository by including the self-healing characteristics of fractures, which wa observed in laboratory as well as in-situ experiments, The applicability of the numerical approaches was verified from the comparison to in-situ measurements of EDZ permeability at underground research laboratories.

• Korean Journal of Ecology and Environment
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• v.33 no.4 s.92
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• pp.405-412
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• 2000

The fine structure of spermatozoa of Leiocassis ussuriensis was examined with scanning and transmission electron microscopies. The spermatozoon of L. ussuriensis is approximately $68.8\;{\mu}m$ in length and a relatively simple cell with a spherical nucleus, a short midpiece and a tail. The ultrastructure of spermatozoa of L. ussuriensis is characterized by the following features. The nuclear fossa, the length of which is about two-thirds of the nuclear diameter, contains two centrioles. The centrioles are orientated approximately $180^{\circ}$ to each other. The mitochondria are arranged in two layers and their number is 12 or more. The axoneme is the 9+2microtubular pattern and has inner but no outer dynein arms as in other bagrids. The two axonemal fins are in the same plane with the two central microtubules, the doublets 3 and 8. The axonemal fins and the inner dynein arm are shared in Bagridae and the deep nuclear fossa is shared in Siluriformes. The axonemal finsobse observed in Bagridae and Amblycipitidae of Siluriformes might be the apomorphic character in Ostariophysi. They are not reported in Cyprinidae and Characiformes.

• The Journal of Engineering Geology
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• v.6 no.3
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• pp.137-153
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• 1996

The purpose of this study is to investigate the possibilities of identifying and detecting underground cavities using seismic waves recorded by the fixed and mobile stations. During 18 months of field work we recorded chemical explosions near the Bongdarn station. Seismic Stations were installed on the free surface and underground inside the Samba mine. The seismograms at the fixed(lorg-term) seismic station show abrupt change of polarization characteristics which can he associated with the appearance of P-to-S converted phase(PS) at 150 ~ 200 msec after the first P arrival. This result indicates that converted phases are generated very near to the Bongdarn station at a depth of 190m. Shear-wave splitting phenomena have also been observeci The time delay between fast shear(fS) and slow shear(sS) waves ranges between 30 and 60 msec(average is 42 msec). However, exact time delay between the fast and the slow shear waves can not be accurately measured because of the very short time delay and limitation of sampling rate. Chemical explosion experiments were recorded at stations along various paths to contrast the seismic response of areas with and without cavities. The seismograms recorded at the stations installed at cavity areas show an abrupt change of polarization characteristics but not on the other stations. Seismic waves propagating through the cavity are characterized by the attenuation of high frequency waves and predominantly low frequency seismic waves after the S wave arrivals.

• Tunnel and Underground Space
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• v.32 no.2
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• pp.120-130
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• 2022

In this study, the applicability of the microseismic monitoring system based on the underground mine communication system has been verified by operation test in the domestic underground mine. The microseismic data consists of wavelet data and meta-data for mine safety management, and both data should be transferred, stored, analyzed and managed with proper method according to the purpose and size of each data. In order to select the optimal communication system for the microseismic monitoring system considering the underground environment as well as properties of data, various types of communication system have been tested and compared during operation test after installing the optical cable communication system, 2.4 GHz and 900 MHz wireless communication system through the underground mine tunnel and overground area of the test site. The integrated microseismic monitoring software, which was developed to secure the stability of data management and ease of use, has been updated according to findings from operation test. Through the operation test of the microseismic monitoring system including the communication system and the monitoring software, the technical basis was established corresponding to various requirements of the domestic mine for adoption of the microseismic monitoring system.