The occurrence of shear failure in a rock mass, resulting from the sliding of joint surfaces, is primarily influenced by the surface roughness and contact area of these joints. Furthermore, since joints serve as crucial conduits for the movement of water, oil, gas, and thermal energy, the aperture and geometric complexity of these joints have a significant impact on the hydraulic properties of the rock mass. This renders them critical factors in related industries. Therefore, to gain insights into the mechanical and hydraulic behavior of a rock mass, it is essential to identify the key morphological characteristics of the joints mentioned above. In this study, we quantified the morphological characteristics of tensile fractures in granitic rocks using X-ray CT imaging. To accomplish this, we prepared a cylindrical sample of Hwang-Deung granite and conducted splitting tests to artificially create tensile fractures that closely resemble rough joint surfaces. Subsequently, we obtained 2D sliced X-ray CT images of the fractured sample with a pixel resolution of approximately 0.06 mm. By analyzing the differences in CT numbers of the rock components (e.g., fractures, voids, and rock matrix), we isolated and reconstructed the geometric information of the tensile fracture in three dimensions. Finally, we derived morphological characteristics, including surface roughness, contact area, aperture, and fracture volume, from the reconstructed fracture.

Rock discontinuities in underground rock behave as weak planes and affect the safety of underground structures, such as high-level radioactive waste disposal and underground research facilities. In particular, rock discontinuities can be a main flow path of groundwater and induce large deformation caused by stress disturbance or earthquakes. Therefore, it is essential to investigate the characteristics of rock discontinuities considering in-situ conditions when constructing highlevel radioactive waste disposal, which needs to assure the long-term safety of the structure. We prepared Hwang-Deung granite rock block specimens, including a saw-cut rock surface, to perform multi-stage direct shear tests as a preliminary study. In the multi-stage direct shear tests, we can exclude possible errors induced by different specimens for obtaining a full failure envelope by using an identical specimen. We applied the initial normal stress of 3 MPa on the specimen and increased the normal stress to 5 and 10 MPa step by step after peak shear stress observation. We obtained the mechanical properties of saw-cut rock surfaces from the experiments, including friction coefficient and cohesion. Additionally, we investigated the effect of filling material between rock discontinuities, assuming the erosion and piping phenomenon in the buffer material of the engineering barrier system. When the filling material existed in the rock surfaces, the shear characteristics deteriorated, and the effect of bentonite was dominant on the shear behavior.

Currently, there are 25 nuclear power plants (NPPs) in operation in Korea, including 22 pressurized water reactors (PWRs) and three pressurized heavy water reactors (PHWRs). Two NPPs, including Kori Unit 1 and Wolsong Unit 1, are permanently shut down and awaiting decommissioning. If Kori Unit 2, which is expected to be permanently shut down soon, is included, the number of decommissioning NPPs will be increased to three. Spent fuels (SFs) are continuously generated during the NPP operation, which are stored in an SF storage pool in NPPs to cool down the decay heat emitted from SFs. For safe NPP operation, SFs must be regarded as waste, and a disposal site must be selected to isolate SFs. However, an appropriate site has yet to be selected in Korea. SFs contain long-lived nuclides with a high specific activity. For disposal, it is important to characterize the nuclides in the fuels and delay the migration of the nuclides to the environment when SFs are placed in a future disposal facility. If the disposal container is broken, the nuclides in the fuels escape from the filling material, such as bentonite. These escaped nuclides are dissolved in groundwater and migrate to the surface of the earth. Thus, it is possible to assess the radiological impact, such as the exposure dose during and after the disposal, if the types and characteristics of nuclides in SFs are known. This study investigated the nuclides in SFs and identified exposure scenarios that may occur in the disposal process of SFs and migration characteristics when the nuclides leak into groundwater to propose a dose assessment methodology for workers and the public.

This study was conducted to examine the effect of new inoculants on in vitro digestibility and fermentation characteristics of high moisture rye silage. Rye was harvested at heading stage and divided into 5 treatments, following: No additives(CON); L. plantarum R48-27(NI1); L. buchneri R4-26(NI2); mixture of NI1 and NI2 at 1:1 ratio(MIX); and L. buchneri(LB). The rye forage was ensiled into 10 L bucket silo for 100 days. In vitro digestibility of dry matter and neutral detergent fiber were highest(p<0.05) in NI2 silage. The pH in NI2 and LB silages were lower(p<0.05) than CON silage. Lactate concentration was highest(p<0.05) in NI1 silage. While concentrations of acetate and propionate were highest(p<0.05) in MIX silage. Lactates : acetate ratio was highest(p<0.05) in NI1 silage, but lowest in LB silage. Butyrate concentrations of NI2 and LB silages were lower(p<0.05) than that in CON and NI1 silages. Lactic acid bacteria (LAB) count in all inoculated silages was higher(p<0.05) than that in CON silage, while yeast count in LB silage was lower than in CON, NI1, and MIX silages. In conclusion, application of NI2 inoculant could improve potentially fermentation quality and digestibility of high moisture rye silage.

This study was carried out to estimate the effect of selected inoculants on chemical compositions and fermentation characteristics of rye silage. Rye was harvested at dough stage and divided into 5 treatments, following: No additives (CON); L. plantarum R48-27 (LP27); L. buchneri R4-26 (LB26); Mixture of LP27 and LB26 at 1:1 ratio (MIX); and L. buchneri (LB). The rye forage was ensiled into 10 L bucket silo for 100 days. The contents of NDF and ADF were lowest (P<0.05) in LB26. The pH in LB26, MIX, and LB were lower (P<0.05) than CON and LP27. Lactate content in LB was higher (P<0.05) than the others, while acetate content in LB26 and LB were higher (P<0.05) than that in CON and LP27. Lactate to acetate ratio was highest (P<0.05) in LB, but lowest in LB26. Lactic acid bacteria (LAB) count in LB was higher (P<0.05) than that in CON, while yeast count in CON was lower than in all silages applied inoculants. In conclusion, silages inoculated with LB26 could improve potentially the aerobic stability caused by increases of acetate and propionate concentrations.

동남아시아에 발생하던 등검은말벌은 최근 국내 뿐만 아니라 프랑스와 일본, 유럽 전역으로 확산되어 전 세계 양봉 산업에 극심한 피해를 주고 있다. 등검은말벌을 방제하기 위해 다양한 방제 방법들이 연구되고 있으며, 그 중 말벌 유인제에 대해 국제적으로 많은 연구가 진행되어 왔으나 이 역시 지속적인 개발이 필요한 실정이다. 따라서 본 연구에서는 시판 유인제와 최근 (주)다목에코텍에서 새롭게 개발한 신규 개발 유인제에 대한 효능 검정을 수행하였 고 양봉장에 출현하는 국내 발생 말벌속의 발생양상을 조사하였다. 담양 1개소와 곡성 2개소에 기존 유인제과 신규 유인제를 장착한 포획기를 각 3쌍씩 설치하여 2016년 9월부터 11월말까지 주 1~2회 관찰하였다. 그 결과 국내 발생 말벌속 중 등검은말벌(7,787 개체)이 가장 많이 포획되었고, 다음으로 장수말벌, 말벌, 좀말벌, 꼬마장수말벌, 털보말벌 순으로 포획되었다. 두 유인제의 포획력 검정 결과, 신규 개발 유인제가 통계적으로 유의하게(P < 0.01) 등검은말벌 포획력이 높음을 보였다.

It is necessary to monitor growth status of the crops due to continuous change of climate causing insecurity in crop cultivation. Low altitude remote sensing(LARS) system is utilized to accurately monitor the growth status of the crops. In this study, models for monitoring fresh weight(FW), one of the major growth factors of Chinese cabbage, were developed with structural indices and simple ratio calculated from bands in remotely sensed canopies by NIR, RE(imaging sensor A) and multispec-4c sensors(imaging sensor B) equipped with fixed-wing UAV depending on vegetation stages of normal planting(NP) and delayed planting(DP) Chinese cabbages. In results of imaging sensor A, the estimation models using structural indices and simple ratio were divided into NP and DP due to different attribute of reflectance in canopies with changed environment condition depending on different planting dates. The estimation models using simple ratio calculated by red edge and visible bands of NP showed better performance than other models, but RMSE was high. The models using simple ratio calculated by same bands of DP were feasible to accurately estimate FW(R2 of more than 0.946 with RMSE of less than 169.5 g). In results of imaging sensor B, the estimation models using structural indices and simple ratio on DP were divided into low to intermediate FW and intermediate to high FW. As a result, estimation models of all structural indices and simple ratio in low to intermediate FW bands were advisable to estimate FW(R2 of more than 0.860 with RMSE of less than 104.7 g). Estimation models of those calculated by red edge and visible bands in intermediate to high FW were only possible to accurately estimate FW(R2 of more than 0.532 with RMSE of less than 400.7 g).

액정을 이용하는 X-선 검출기에서 전면광원을 적용하는 액정 X선 검출기를 제안하였고 X선 영상을 찍 어 작동을 확인하였다. 제안한 방식은 빛을 이용하므로 트랜지스터를 이용하는 방식에 비해 잡음이 적고 제작 비용을 낮출 수 있다. 액정을 이용하는 검출기는 광도전층을 이용하여 입사 X선을 액정의 분자 배열 변화로 유도하고 액정을 통과하는 빛의 변화량을 읽도록 한다. X선을 조사하고 잰 빛의 투과율과 이것에 대응되는 기준투과율 곡선의 전압으로부터 X선 조사량을 교정(Calibration)하는 과정을 정립하였다. 비정질 셀레늄을 광도전층으로 적용하였으며 200℃ 이상의 고온 처리가 필요한 배향막 공정 대신 패럴린 배향막을 사용하는 공정을 확립하였다. 제안된 액정 X선 검출기의 경우, 방사선량을 획기적으로 줄일 수 있다는 것을 시뮬레이션으로 보였다. 제안된 방식의 X-선 검출기를 제작하고 액정 바이어스 전압을 조절하며 X-선 라인 영상을 비교하였으며 고정 바이어스에서 시간에 따른 이미지 변화를 관찰하였다. 영상사진으로 10 lines/mm의 선패턴을 구별할 수 있었다. 이러한 실험을 바탕으로 검출 패널의 위상이 3π 정도인 17인치 시제품에 적용하여 저선량 액정 X선 검출기의 상용화를 추진할 예정이다.

In this study, we evaluated the antioxidant activity and anti-inflammatory effects of Abeliophyllum distichum (A. distichum) leaves that were prepared via air-drying. Fresh and air-dried A. distichum leaves were examined via 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical, and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging assay and measurements of the reducing power. The suppression effects on inflammation of the leaves were analyzed by a western blot and RT-PCR on LPS-induced RAW 264.7 cells. As a result, the antioxidant activity of the fresh leaves was found to be more effective than that of the air-dried leaves. Also, the fresh leaves were more effective in suppressing the protein and mRNA levels of iNOS and COX-2 than the air-dried leaves, thereby indicating the better anti-inflammatory effects. In addition, the contents of phenolic compounds and acteoside were analyzed by high-performance liquid chromatography (HPLC). The results showed that the acteoside content decreased with the use of the air-drying method, while there was no change in the content of phenolic compounds. Therefore, this study indicated that fresh A. distichum leaves potential antioxidant and suppression activities of various factors that are involved in the production of NO, which were found to be better than those of air-dried A. distichum leaves. These biological activities were also found to be independent of the content of phonolic compounds and were assumed to be directly or indirectly related to the content of acteoside.

This study was conducted to investigate egg development and larvae morphological development of catfish and to provide basic data to clarify the genetic relationship with Siluriformes fish. The mother fish that was used in this study was caught in the stream of Nakdong River in Uiseong-gun, Gyeongbuk. The temperature range of the breeding was 23.0- 25.0℃ (mean 24.0±1.0℃) and egg size was 1.62-1.70 mm (mean 1.66±0.05, n=30). Eggs of catfish began hatching at 54 hours and 40 minutes after fertilization. Immediately after hatching, the total length of larvae was 3.60-3.65 mm (mean 3.62±0.03, n=5) and had an egg yolk without swimming ability. On the third day after hatching, the larvae at the medium stage was 8.00-8.65 mm (mean 8.32±0.45) in total length, and two pairs of whiskers formed around the mouth were elongated. On the 12th day after hatching, the larvae at the juvenile stage was 16.5-17.0 mm (mean 16.7±0.35) in total length, and the stem of each fin was in the range, and the juvenile at this period was morphologically similar to the mother fish.

Since cable members are the major structural components in cable bridges, they should be properly inspected for surface damage as well as inside defects such as corrosion and/or breakage of wires. Starting from August 2010, a new research project supported by Korea Ministry of Land, Transportation Maritime Affairs (MLTM) was initiated to develop the cable inspection robot. In this study, only the vision-based surface damage detection system based on image processing techniques is addressed. The damage detection algorithm combines some image enhancement techniques with principal component analysis (PCA) to detect damages on cable surface. The images from three cameras attached to the cable climbing robot are wirelessly transmitted to the server computer at the cable support. They are processed with image enhancement method together with noise removal technique to improve overall image quality. Then they are projected into PCA sub-space. Finally, the Mahalanobis square distances of the projected images to all sample patterns are calculated. The smallest distance is found to be the match for the input image. The proposed damage detection algorithm was verified through laboratory tests on three types of cables.