With medical use of hemp, many medicinal cultivars were bred worldwide. Propagating cultivar using seed has a high cost. On the other hand, vegetatively propagating cultivar has various merits including short breeding period and uniformity. This study aimed to determine optimal conditions for propagating hemp after cutting, including sterilizing of rooting media, rooting hormone, and mixing ratio of growing media and sand of rooting media. Korean landrace strain of hemp plant was grown in Wagner pot (size: 1/2,000 a) for 60 days. Its branches were cut to 70∼80 mm in length and used for cutting slips. The rooting medium, a horticultural nursery medium, was autoclaved for 3 hours at 120 ℃. The mixing ratio of sand and nursery media was 9:1, 7:3, 5:5, or 3:7 in weight. Cutting slips were coated with rooting hormone (1-naphthylacetamide 0.4%) just before planting. Cutting materials were planted in a tray pot of 72 cells and grown in a walk-in-chamber for 28 days with a temperature of 25 ℃ and an intensity of radiation of 800 μmol/㎡/sec. Seedling rates were 61.1%, 77.8%, and 63.0% for mixing ratios of 1:9, 3:7, and 5:5 of sand mixed with horticultural nursery medium. These seedling rates were significantly higher than a seedling rate of 31.5 % for a mixing ratio of 7:3. Root lengths were 97 mm, 91 mm, and 81 mm for mixing ratios of 1:9, 3:7, and 5:5 of sand mixed with horticultural nursery medium. These root lengths were significantly longer than a root length of 37 mm for a mixing ratio of 7:3. Rooting rates were 81.1 % and 91.2 % for slips coated with rooting hormone and sterilized rooting media, respectively. They were 40.0 % and 18.3 % for slips not coated with rooting hormone or sterilized rooting media, respectively. Thus, for vegetative propagating (cutting) of medicinal hemp, sterilizing of rooting media and coating slips with rooting hormone will be essential to conducting the propagation process.

태안군 신두리 대조차 해빈에 나타나는 다중사주의 여름철 출현과 겨울철 사라짐 패턴을 조사하고 이들이 어떻 게 겨울철에 소멸하고, 여름철에 다시 생성되는지를 토의하였다. 계절에 따른 다중사주의 지형변화는 VRS-GPS 시스템 을 이용하여 지난 4년 동안 주기적으로 해빈 측선측량을 실시하여 파악하였다. 사주의 구성퇴적물을 알아보고자 계절에 따른 표층퇴적물을 채취하여 입도분석을 수행하였다. 추가적으로 유속자료를 확보하기 위해, TIDOS 조류관측시스템을 여름과 겨울에 각각 설치하여 얻었다. 신두리 해빈은 급경사의 상부 사빈면과 완만한 하부 조간대 지역으로 구분된다. 사빈면은 범(berm)의 발달이 미약하고, beach cusp가 나타나지 않아 매우 단조로운 지형을 갖고 있다. 조간대 지역은 폭이 400 m로서 넓고 2 - 5개의 사주열이 나타난다. 사빈의 구성 퇴적물 평균입도는 2.0-2.75 phi 범위로 세립사에 해당하 며, 육지방향으로 갈수록 조립해지는 경향을 띤다. 반복적 측선측량 결과, 신두리 해빈은 여름철 다중사주가 최대 5열 까지 발달하는 해빈 단면을, 반면 겨울철에는 사주의 발달이 없는 편평한 해빈 단면을 갖는다. 겨울철 다중사주의 사라 짐은 겨울의 강한 파랑으로 사주의 마루가 침식되고 골에 퇴적되는, 깎고 채움의 결과로 해석된다. 여름철 다중사주의 생성은 고조 시 정지상태에서 정상파 운동에 의해 생성되기보다는 조위면의 이동과 평상 파랑이 결합된 break-point 기 작으로 설명된다. 평균해수면 근처의 사주가 가장 크고 뚜렷함, 육지방향으로 갈수록 사주의 진폭이 감소함, 다중사주 진폭의 불규칙함, 사주의 강한 비대칭, 그리고 육지방향으로 10-30 m 사주의 이동은 break-point 기작을 뒷받침한다.

The separation of zirconium and hafnium using tributyl phosphate (TBP)-Dodecane extractants in nitric acid medium was performed. Zirconium oxychloride, used as extraction feed, was obtained from the synthesis of Kalimantan zircon sand concentrate smelted using NaOH. The extraction process was carried out by dissolving chloride-based metals in nitric acid media in the presence of sodium nitrate using TBP-Dodecane as an extractant. Some of the extraction parameters carried out in this study include variations in organic phase and aqueous phase (O/A), variations in contact time, and variations in nitric acid concentration. Extraction was carried out using a mechanical shaker according to the parameter conditions. X-ray fluorescence (XRF) was used for elemental (Zr and Hf) composition analysis of the aqueous solution. The results showed that zirconium was separated from hafnium at optimum conditions with an organic/aqueous ratio of 1:5, contact time of 75 min, and an HNO3 concentration of 7 M. The resulting separation factor of zirconium and hafnium using TBP-Dodecane was 14.4887.

본 연구는 우리나라 최남단에 위치한 제주특별자치도 사계 해안사구의 식생에 따른 군락분포와 식물상을 파악하기 위해 수행되었다. 연구는 2020년 4월부터 2021년 10월까지 총 20회에 걸쳐 이루어졌다. 연구 결과, 상관식생형은 해안 염습지식생, 해안정선 일이 년생 초본식생, 해안사구 초본식생, 해안사구 관목식생, 임연식생, 인공조림식생 6개의 상관식생형으로 분류되었다. 군락은 43개 군락이 분포하며, 전체 출현 식물은 62과 166속 191종 15변종 3아종 3품종으 로 총 212분류군이 분포하는 것으로 조사되었다. 환경부지정 멸종위기 Ⅱ급 식물인 대홍란을 포함하여 희귀식물 5분류 군이 분포하는 것으로 나타났으며, 식물구계학적 특정 식물종은 V등급 2분류군, IV등급 5분류군, III등급 15분류군, II등급 14분류군, I등급이 19분류군으로 조사되었다. 기후변화 생물 지표종은 지표종 11종 후보종 2종이 분포하여 전체 지표종의 33.3%, 후보종은 15.4%로 높은 비율을 보였다. 귀화식물은 16과 43속 52분류군으로 귀화율 21.1%이며, 도시화지수는 24.5%로 높게 나타났다. 이러한 결과는 향후 해안사구의 기후변화에 따른 생물다양성의 보전과 관리 방안을 마련하는 데 필요한 자료로 널리 활용될 것이 기대된다.

Understanding the behavior of soil under cyclic loading conditions is essential for assessing its response to seismic events and potential liquefaction. This study investigates the effect of non-plastic fines content (FC) on excess pore pressure generation in medium-density sand-silt mixtures subjected to strain-controlled cyclic direct simple shear (CDSS) tests. The investigation is conducted by analyzing excess pore pressure (EPP) ratios and the number of cycles to liquefaction (Ncyc-liq) under varying shear strain levels and FC values. The study uses Jumunjin sand and silica silt with FC values ranging from 0% to 40% and shear strain levels of 0.1%, 0.2%, 0.5%, and 1.0%. The findings indicate that the EPP ratio increases rapidly during loading cycles, with higher shear strain levels generating more EPP and requiring fewer cycles to reach liquefaction. At 1.0% and 0.5% shear strain levels, FC has a limited effect on Ncyc-liq. However, at a lower shear strain level of 0.2%, increasing FC from 0 to 10% reduces Ncyc-liq from 42 to 27, and as FC increases further, Ncyc-liq also increases. In summary, this study provides valuable insights into the behavior of soil under cyclic loading conditions. It highlights the significance of shear strain levels and FC values in excess pore pressure generation and liquefaction susceptibility.

To determine the cause of the population decline in Gobiobotia naktongensis, substrate preference and burying behaviour were investigated in this study. In general, the species was shown to prefer a substrate size of 1 mm or less, depending on the flow. In addition, the burying depth varied according to the size of the fish and increased with a decrease in water temperature. Our findings showed that the main cause of the population reduction was the physical changes in the substrate structure due to the dams or barrages construction. Notably, the accumulation of silt and mud in the substrate upon the formation of an upstream lentic water region for structural construction and bed armouring caused by scouring and reduced downstream inflow of fine sediment were deterministic in the fish habitat changes, causing problems in burying. As sand substrate structure is critical for the survival and inhabitation of psammophilous species, efficient strategies should be developed with proper habitat management to reduce the anthropogenic damage

대한해협 대륙붕 해저사퇴의 형성과정을 이해하기 위해 77m 심도 심부 SSDP-101 코어를 연구하였다. 이 심부 코어는 WGS 측지계 기준으로 북위 128도 16.335분, 동경 34도 19.666분에 위치한 수심 60m의 사퇴 정상부에서 시추 하였다. SSDP-101 코어 시료의 해양지질학적 분석은 제4기 후기 상대 해수면 변화에 의해 야기된 대한해협 대륙붕 퇴 적환경의 변화를 밝혔다. 하부 코어 퇴적층은 간헐적 하천 범람이 일어나는 염하구 환경에서 형성된 것으로 해석되었다. 연구 지역의 사퇴는 상대해수면이 현재보다 더 낮은 시기에 형성되었고, 사퇴 퇴적물은 상대해수면이 상승함에 따라 키 질작용을 받았다. 현재 대륙붕의 해저사퇴는 해수면이 낮았던 시기의 해저사퇴가 현재 해수면 환경까지 잔존된 결과로 해석된다.

본 연구는 강원도 강릉시에 위치한 하시동·안인사구 생태경관보전지역에서의 생태계서비스 평가와 증진방안 마련을 위하여 시행되었다. 연구방법으로 신속평가 도구를 이용한 생태계서비스 평가를 바탕으로 환경지속성지수 분석하였고, SWOT 분석 을 통하여 생태계서비스 증진방안을 마련하였다. 하시동·안인사구 생태경관보전지역의 생태계서비스 평가 결과를 바탕으로 분석한 환경지속성지수는 조절서비스, 문화서비스, 지지서비스 모두 50% 미만으로 낮게 평가되었다. 특히 문화서비스, 지지서 비스가 부족한 것으로 나타났다. 이러한 결과를 바탕으로 하시동·안인사구 생태경관보전지역의 생태계서비스 증진 방안을 마련하기 위하여 SWOT 분석을 시행하였다. 강점을 기회로 활용(SO전략), 강점을 이용한 위협요인 최소화(ST전략), 강점을 보완하기 위하여 기회를 활용(WO전략), 약점을 보완하고 위협을 최소화(WT전략)하는 생태계서비스 증진방안 6가지를 도출 하였다. 향후 하시동·안인사구 생태경관보전지역에서 생태계서비스 증진사업을 추진할 때 현재 훼손된 지역의 복원과 향후 침식 등으로 인한 피해 방지 등 제시한 문제를 극복하고 이를 통하여 생태계서비스를 증진시켜 하시동·안인사구 생태경관보전 지역의 가치를 높일 필요가 있다.

A taxonomic study of Korean Psammodiini is present. Seven species [Rakovicius coreanus (Kim), Leiopsammodius japonicus (Harold), Psammodius flavolittoralis Kim, Psammodius hangangensis Kim, Psammodius sungshinarum Kim, Rhyssemus inscitus (Walker), Trichiorhyssemus asperulus (Waterhouse)] belonging to five genera are recognized based on morphological characters. A pictorial key, habitus photographs and illustrations of the diagnostic characters of Korean Psammodiini species are provided to facilitate identification.

To identify sand crab Ovalipes punctatus populations and establish management units for each population, mtDNA COI regions were analyzed. As a result, the clade of O. punctatus in Korea were separated by two with a genetic distance of 0.17 – 2.08%, and there was no significant difference in the result of pairwise FST values representing genetic differentiation by sampling areas (p > 0.05). Also, no geographical separation found in the distribution of haplotypes and the results of the haplotype network. This result suggests that O. punctatus larvae were dispersed for a long time by the ocean current by suffering meroplanktonic period for 1 month, and increased the gene flow due to the development of the swimming legs for the increase in mobility. Therefore, in the results of mtDNA COI region analysis of O. punctatus in the East Sea, Yellow Sea, South Sea and East China Sea (Ieodo) of Korea, no clear intra-species differentiation was found.

Backfill is one of the key elements of deep geological disposal. The backfill material is used to fill disposal tunnels and is mainly composed of swellable clay, preventing the migration of nuclide and structurally supporting the tunnel. The selection and application of backfill material are critical for the stable and efficient disposal of spent fuel. Therefore, it is essential to secure various candidate materials for backfill and to comprehensively understand the properties and behavior of these materials. Recently, the Korea Atomic Energy Research Institute has selected a candidate material called Bentonil-WRK and is evaluating its applicability. To utilize this material as backfill, the safety function of a mixed backfill concept, consisting of sand and Bentonil-WRK, was assessed. The swelling pressure was measured as a function of dry density for a bentonite/silica sand mix ratio of 3/7. The results showed that the swelling pressure ranged from 0.15 to 0.273 MPa, depending on the dry density, with higher dry densities resulting in higher swelling pressures. The measured swelling pressure met the target performance criteria suggested by SKB and Posiva (i. e., 0.1 MPa), but did not meet the design requirement for swelling pressure (i. e., 1 MPa). This indicate the need for further research after increasing the mass fraction of bentonite (e. g., mix ratio 4/6 or more). The results of this study are expected to be used in the selection of candidate backfill materials and the establishment of design guidelines for engineered barrier backfill.

In order to reduce the area of the high-level radioactive waste (HLW) repository, a buffer material with high thermal conductivity is required. This is because if the thermal conductivity of the buffer material is high, the distance between the disposal tunnels and the deposition holes can be reduced. Sand, which is a natural material and has higher thermal conductivity than bentonite, is added to bentonite to develop an enhanced buffer material. For the sand-bentonite mixture, it is important which sand to use and how much to add because an enhanced buffer material should satisfy both hydraulic (H) and mechanical (M) performance criteria while improving thermal conductivity (T). In this study, we would like to show what type of sand and how much sand should be added to develop an enhanced buffer material by adding sand to Gyeongju bentonite, a representative bentonite in Korea. For this purpose, the thermal conductivity, hydraulic conductivity, and swelling pressure of the sand-Gyeongju bentonite mixture according to the sand addition rate were measured. It is more efficient to use silica sand with smaller particles than Jumunjin sand which is a representative sand in Korea as an additive for an enhanced buffer material than using the Jumunjin sand. In order for the sand-Gyeongju bentonite buffer material to satisfy both the hydraulic and mechanical performance criteria as a buffer material while increasing the thermal conductivity, it is judged that the optimum dry density is 1.7 g/cm3 at least and the optimum sand addition rate is 10% at most.

Among the Additive Manufacturing (AM) technologies, the Binder-Jetting printing technology is a method of spraying an adhesive on the surface of powder and laminate layer by layer. Recently, this technique has become a major issue in the production of large casting products such as ship-building, custom vehicles and so on. In this study, we performed research to make actual mold castings and increase mechanical property by using special sand and water-based binders. For use as a mold, it has a strength of more than 3MPa and permeability. Various experiments were carried out to obtain suitable them. The major process parameters were binder jetting volume, binder types, layer thickness and heat treatment condition. As a result of this study, the binder drop quantity was measured to be about 60 pico-liter, layer thickness was 100μm and the heat treatment condition was measured about 1,000℃ and compressive strength were measured to be more than 5MPa. The optimum condition of this experiment was established through actual casting of aluminum. The equipment used in this study was a Freeforms T400 model (SFS Co., Ltd.), and the printing area of 420 * 300 * 250mm and resolution of 600dpi can be realized.