Since their initial development in 2012, triboelectric nanogenerators (TENGs) have gained popularity worldwide as a desired option for harnessing energy. The urgent demand for TENGs is attributed to their novel structural design, low cost, and use of large-scale materials. The output performance of a TENG depends on the surface charge density of the friction layers. Several recycled and biowaste materials have been explored as friction layers to enhance the output performance of TENGs. Natural and oceanic biomaterials have also been investigated as alternatives for improving the performance of TENG devices. Moreover, structural innovations have been made in TENGs to develop highly efficient devices. This review summarizes the recent developments in recycling and biowaste materials for TENG devices. The potential of natural and oceanic biowaste materials is also discussed. Finally, future outlooks for the structural developments in TENG devices are presented.

본 연구는 대한민국 울릉도 특산식물인 추산쑥부쟁이(Aster × chusanensis Y.S.Lim, Hyun, Y.D.Kim & H.C.Shin)의 기내 대량증식체계 확립을 위해 시토키닌 계열 식물생장조절 제를 첨가하여 캘러스 및 신초 형성 조건을 구명하고자 수행 하였다. 실험결과, 추산쑥부쟁이의 줄기 절편체에서 캘러스 와 신초가 형성되었다. 캘러스 형성률은 TDZ 3.0mg·L-1처 리구에서 88.9%로 가장 높았고 BAP 3.0mg·L-1와 Zeatin 3.0mg·L-1 처리구는 66.7%, 2iP 3.0mg·L-1 처리구에서는 11.1%였다. 신초 형성률은 모든 처리구에서 77% 이상이고 특히 TDZ처리구와 Zeatin 처리구에서 100%였다. 그러나 TDZ처리구에서는 형성된 신초가 부풀어 오르거나, 잎에 과수 성이 나타나는 등 형태적 기형이 나타났다. Zeatin처리구에 서 발생한 신초는 정상적인 형태를 나타났다. 잎 절편체에서 는 캘러스, 신초가 발생하지 않았으며 절편체가 탈색하며 고 사하는 것을 확인하였다. 종합적으로 추산쑥부쟁이의 캘러 스 및 신초 형성을 위해서는 줄기 절편체를 배양 재료로 이 용하는 것이 효과적으로 확인되었다. 캘러스 유도에는 TDZ 3.0mg·L-1처리가 가장 효과적이었고, 추후 NAA와 같은 옥신 을 함께 첨가하여 증식 효과를 분석하는 연구가 필요할 것이 다. 또한, 신초 유도에도 TDZ 3.0mg·L-1 처리가 효과적이었 으나 장기간, 고농도로 사용할 경우 형태적인 기형이 발생할 수 있어 정상적인 식물생산에 부적합한 것으로 확인되었다. 따라서 형태적 기형이 발생하지 않은 아데닌 유도체형 시토키 닌인 Zeatin을 활용하는 것을 추천한다. 본 연구는 울릉도 특 산식물인 추산쑥부쟁이의 기내 대량증식과 생태계 유지에 필 요한 종 공급을 위한 대량증식 체계 구축을 위한 자료로 활용 할 수 있을 것이다.

자생 부추속 식물 중 강부추(Allium thunbergii for. rheophytum ined.)와 갯부추(A. pseudojaponicum Makino)는 관상용, 식 용 및 약용자원으로 가치가 있으나 육묘를 위한 생육환경조건 구명이 미비하여 연구할 필요성이 있다. 본 연구는 강부추와 갯부추의 육묘에 미치는 플러그 셀 크기, 차광률, 시비처리에 따른 영향을 구명하기 위하여 실험을 수행하였다. 강부추와 갯부추를 육묘한 결과, 플러그 셀 크기에서는 50, 72, 105, 128, 162, 200셀 처리 중 용적이 가장 큰 50셀에서 초장, 엽 수, 근수, 그리고 근장의 생육이 우수하였다. 그러나 생산비용 과 플러그 육묘의 효율성을 고려하여 105셀 이상의 플러그 트레이 중에서 선택하여 육묘하는 것이 효과적이라 판단된다. 차광률에 따른 유묘는 0, 30, 60, 90% 처리 중 30~60% 차 광처리에서 초장, 근수, 그리고 근장이 유의적으로 높게 측정 되어 생육이 양호하였다. 시비처리에서 생중량과 건중량을 제 외한 생육지표를 검토했을 때, 강부추의 적정 시비처리는 속 효성 고형비료(DO-PRO) 0.1g, 갯부추는 속효성 액체비료 (Peters) 주 1회 8mL 엽면시비처리였고 두 종 모두 속효성 시비처리가 효과적이었다. 강부추와 갯부추의 초기 생육에는 30~60% 차광처리가 된 재배플롯에서 원예상토가 충진된 128셀 플러그 트레이에 종자를 파종한후, DO-PRO 0.1g 또 는 Peters 8mL를 주 1회 엽면시비하면서 재배하는 것이 효 과적이라 판단된다.

Heavy water (deuterium oxide, D2O) is water in which hydrogen atoms (1H, H), one of the constituent elements of water molecules, have been replaced with deuterium (2H, D), a heavier isotope. Heavy water is used in a variety of industries, including semiconductors, nuclear magnetic resonance, infrared spectroscopy, neutron deceleration, neutrino detection, metabolic rate studies, neutron capture therapy, and the production of radioactive materials such as plutonium and tritium. In particular, heavy water is used as a neutron moderator or coolant in nuclear reactors and as a fuel for nuclear fusion energy, methods for measuring heavy water are becoming increasingly important. There are methods with density, mass spectrometry, and infrared (IR) spectroscopy. In this study, Fourier transform infrared spectroscopy (FT-IR) was used, which is commonly used in IR spectroscopy because of its relatively high analytical sensitivity, low operating costs, and easy online analysis. Heavy water was identified in the range of 2,300-2,600 cm-1 wavenumber (O-D) and the range of 1,200-1,300 cm-1 wavenumber (D-O-D), which are known to be the range with strong infrared absorption. As a result, the linearity of infrared absorbance for each heavy water concentration was confirmed within the relative expansion uncertainty (k=2).

The mobility of radionuclides in the subsurface environment is governed by a interaction of radioactivity characteristics and geochemical conditions with adsorption reactions playing a critical role. This study investigates the characteristics and mechanisms of radionuclides adsorption on site media in viewpoint of nuclear safety, particularly focusing on the potential effect of seawater infiltration in coastal site near nuclear power plant. Seawater intrusion alters the chemistry in groundwater, including parameters such as pH, redox potential, and ionic strength, thereby affecting the behavior of radionuclides. To assess the safety of site near nuclear power plant and the environmental implications of nuclide leakage, this research conducted various experiments to evaluate the behavior of radionuclides in the subsurface environment. High distribution coefficients (50-2,500 ml/g) were observed at 10 mg/L Co, with montmorillonite > hydrobiotite > illite > kaolinite. It decreased with competing cations (Ca2+) and was found to decrease significantly by 90% with a decrease in pH to 4. It is believed that the adsorption capacity of cationic radionuclides decreases significantly as the clay mineral surface becomes less negatively charged. For Cs, the distribution coefficient (180-560 ml/g) was higher for montmorillonite > hydrobiotite > illite > kaolinite. Compared to Co, it was found to be less influenced by pH and more influenced by competing cations. For Sr, the distribution coefficient (100-380 ml/g) was higher in the order of hydrobiotite > montmorillonite > illite > kaolinite. Compared to Cs, it was found to be less affected by pH and also less affected by the effect of competing cations compared to Cs. Seawater samples from Gampo and Uljin site near Nuclear Power Plant in Korea were analyzed to determine their chemical composition, which was subsequently used in adsorption experiments. Additionally, the seawater-infiltrated groundwater was synthesized in laboratory according to previous literature. The study focused on the adsorption and behavior of three key radionuclides such as cesium, strontium, and cobalt onto four low permeability media (clay minerals) such as kaolinite, illite, hydrobiotite, and montmorillonite known for their high adsorption capacity at a site of nuclear power plant. At concentrations of 5 and 10 mg/L, the adsorption coefficients followed the order of cobalt > cesium > strontium for each radionuclide. Notably, the distribution coefficient (Kd) values exhibited higher values in seawater-infiltrated groundwater environments compared to seawater with relatively high ionic strength. Cobalt exhibited a substantial adsorption coefficient, with a marked decrease in Kd values in seawater conditions due to elevated ionic strength. In contrast, cesium displayed less dependency on seawater compared to other radionuclides, suggesting distinct adsorption mechanisms, possibly involving fractured edge sites (FES) in clay. Strontium exhibited a significant reduction in adsorption in seawater compared to groundwater in all Kd sorption experiments. The adsorption data of cobalt, cesium, and strontium on clay minerals in contact with seawater and seawater-infiltrated solutions offer valuable insights for assessing radioactive contamination of groundwater beneath coastal site near nuclear power plant sites. This research provides a foundation for enhancing the safety assessment protocols of nuclear power plant sites, considering the potential effects of seawater infiltration on radionuclide behavior in the subsurface environment.

KORAD (Korea Radioactive Waste Agency, http://www.korad.or.kr) has stored slightly contaminated ascon (asphalt coated concrete mixture) that was introduced to Gyeongju repository about a decade ago waiting for a final disposal. It is believed to be mainly contaminated by radioisotope 137Cs due to impurities introduced from the outside during the ascon manufacturing process. We studied characteristics of the radioactive waste to see whether this material would be proper enough to be disposed in Gyeongju LILW repository or be other ways to reduce the disposal volume including self-disposal before its final disposal otherwise. KORAD looked into the properness of characteristics of ascon in terms of WAC (Waste Acceptance Criteria) documented by KORAD that includes general chemical and physical properties of asphalt, density, size of grains, content of organic material and possibility of existence of chelate materials that qualitatively limited to be disposed by the criteria. And other associated characteristics such as gas generation and bio degradation were also investigated. Based on the data obtained from the study, we proposed various plausible solutions in associated with operational and disposal safety and economic view points. This study will be used for KORAD’s decision on how to control and safely dispose the spent ascon within a reasonable time period. And also those experiences may be applied for other LILW issues that require treatment or conditioning of radioactive wastes in the future.

The oriental fruit fly, Bactrocera dorsalis, is one of important agricultural pests that attack a wide range of fruits and vegetables. Adult female can cause direct damage by laying eggs under the skin of fruits and vegetables. The eggs hatch into larvae that feed in the decaying flesh of the agricultural crops. Damaged fruits and vegetables quickly become inedible or dropto the ground. We investigated the oviposition characteristics of B. dorsalis on twelve fruits and seven vegetables. B. dorsalis marked the oviposition places on every crop tested. B. dorsalis laid eggs into the fruits and vegetables except lemon and passionfruit. We examined the adult emergence from infested crops.

곤충병원성 선충인 Heterorhabditis. megidis(큰형광병원선충)는 참나무 군락지(광주광역시 소재) 사양토에 서 분리 동정되었고, 곤충병원성을 가지는 공생세균은 Photorhabdus temperata로 분리 동정되어 각각 GJ1-2로 명명하였다. H. megidis GJ1-2는 고추(녹광), 애호박(농우), 오이(백다다기), 참외(금싸라기), 토마토(베타티니) 유묘기 경엽처리와 배추(씨알천하일품), 상추(진청맛), 완두(청진주), 수박(삼복꿀), 무(서호) 유묘기 관주처리 에서 21일차까지 기준량과 배량에 대하여 약해(약해 판정기준결과: 0)가 나타나지 않았다, H. megidis GJ1-2는 배추 파밤나방에 대한 방제 효과는 이천시(경기도 소재)와 수원시(경기도 소재)의 시설재배 포장에서 각각 경엽 처리 3일차 71.8%. 73.9%, 7일차 86.2%, 84.6%로 나타났으며, 옥수수 열대거세미나방에 대한 방제 효과는 제주시 (제주특별자치도 소재)의 노지(미사질 양토)에서 경엽처리 7일차 82.6%로 나타났다. 그리고 H. megidis GJ1-2는 랫드를 이용한 급성경구와 급성경피 독성시험 반수치사농도(LD50) 값은 2,000 mg/kg B.W 초과로 IV급(저독성) 으로 구분되었고, 토끼를 이용한 피부와 안점막에 자극성이 없는 것으로 구분되었다. 그리고 담수어류(송사리) 에 대한 급성독성시험 반수치사농도(LD50) 값은 영향을 미치지 않는 기초시험농도 100 mg/L를 초과하였다.

강원특별자치도 18개 시군을 대상으로 감나무와 콩에 발생하는 미국선녀벌레, 썩덩나무노린재, 담배거세미 나방의 발생을 조사하였다. 돌발해충인 미국선녀벌레는 약충기인 6월과 성충기인 10월에 발생조사를 진행하고 남방계해충인 담배거세미나방과 썩덩나무노린재는 7월과 9월 콩 재배기에 발생조사를 진행하였다. 미국선녀 벌레는 강원지역에 있는 감나무에서 발생을 확인할 수 없었고. 감나무 주변 기타 수목에서 가지당 평균 6.7마리 발생하였다. 담배거세미나방은 7월, 속초를 제외한 모든 시군에서 발생이 되었으며, 춘천, 횡성에서 트랩당 60마 리가 넘는 발생밀도를 보였으며, 원주, 강릉, 화천 등 에서는 트랩당 1마리로 낮은 발생밀도를 나타냈다. 썩덩나무 노린재는 7월 춘천, 속초, 홍천 등 7개 시군을 제외한 11개 시군에서 트랩에 포획되는 것을 확인하였으며, 화천에 서 트랩당 26마리로 최고발생밀도를 보였다.

It is difficult to distinguish the pure signal produced by an orbiting planetary companion around giant stars from other possible sources, such as stellar spots, pulsations, or certain activities. Since 2003, we have obtained radial (RV) data from evolved stars using the high-resolution, fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) at the Bohyunsan Optical Astronomy Observatory (BOAO). Here, we report the results of RV variations in the binary star HD 135438. We found two significant periods: 494.98 d with eccentricity of 0.23 and 8494.1 d with eccentricity of 0.83. Considering orbital stability, it is impossible to have two companions in such close orbits with high eccentricity. To determine the nature of the changes in the RV variability, we analyzed indicators of stellar spot and stellar chromospheric activity to find that there are no signals related to the significant period of 494.98 d. However, we calculated the upper limits of rotation period of the rotational velocity and found this to be 478–536 d. One possible interpretation is that this may be closely related to the rotational modulation of an orbital inclination at 67–90 degrees. The other signal corresponding to the period of 8494.1 d is probably associated with a stellar companion orbiting the giant star. A Markov Chain Monte Carlo (MCMC) simulation considering a single companion indicates that HD 135438 system hosts a stellar companion with 0.57+0.017 −0.017 M⊙ with an orbital period of 8498 d.

The aim of this study was to determine the contamination of mycotoxins and the concentration of preservatives and antioxidants in commercial pet food. 106 pet foods were purchased from online in Korea. Mycotoxin analysis were performed using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) and preservatives and antioxidants were analyzed by high performance liquid chromatography (HPLC). The contamination of the mycotoxins in all samples was proved to comply with the Korea legislation with regards to animal feed, the analyses revealed presence of aflatoxins, ochratoxin A, zearalenone and fumonisins, with values below 1.6 ㎍/㎏, 12.1 ㎍/㎏, 478.5 ㎍/㎏ and 1873.5 ㎍/㎏, respectively. Furthermore, the simultaneous presences of different mycotoxins were observed in most of positive samples. The levels of dehydroacetic acid (DHA), sorbic acid (SA) and benzoic acid (BA) were, respectively, with values below 0.24 g/㎏, 4.82 g/㎏ and 6.35 g/㎏. The concentrations of butylated hydroxy anisole (BHA) and butylated hydroxy toluene (BHT) were demonstrated to be acceptable, with values below 0.04 g/㎏, and 0.02 g/㎏. This indicated the need for further investigation into the potential risk deriving from chronic exposure to low doses of mycotoxins. Additionally, a co-contamination of mycotoxins which interact in synergic manner are more concern. As DHA that not accepted was detected and very high levels of SA were identified in samples, an upper limit for preservatives in pet foods should be established in pet foods. BHA and BHT were detected within the recommended levels for antioxidant content, so these are considered as safe.

Some consumer goods containing radioactive substances are in circulation and used in everyday life. In accordance with the Nuclear Safety Act, consumer goods with radioactivity are regulated. However, since most consumer goods distributed in Korea have no information that can confirm the amount of radiation, it is necessary to analyze the radiation for safety regulation. Among these consumer goods, GTLS (Gaseous Tritium Light Source) contains gaseous tritium (tritium, written as 3H or T), which is a radioactive material. The gaseous composition ratio in GTLS was analyzed using a precision gas mass spectrometer (Thermo Fisher, model MAT 271). As a result of GTLS analysis, the H2, HD or H3 +(T) or 3He, HT or D2 or He, DT, and T2, which correspond to the mass-to-charge ratio (m/z) 2 to 6 and the air components were detected. In addition, substances corresponding to m/z=24 and m/z=21 were also detected. These were compared with pure CH4 and those fragmentation patterns. The ratios of CT4 (m/z = 24) to CT3 (m/z = 21) and CH4 (m/z = 16) to CH3 (m/z = 15) were compared and they agree within the measurement uncertainty. We also performed additional experiments to separate the water component in the GTLS samples, considering the possibility that the m/z = 21 to m/z = 24 region is tritium compounds based on H2O. Despite the removal of the water components, peaks were detected at m/z=21 and m/z=24. Therefore, we confirmed that the component of m/z = 24 in the GTLS sample was CT4.

The mobility of radionuclides is largely determined by their radiological properties, geochemical conditions, and adsorption reactions, such as surface adsorption, chemical precipitation, and ion exchange. To evaluate the safety assessments of radionuclides in nuclear sites, it is essential to understand the behavior and mechanism of radionuclides onto soils. Since nuclear power plants are located in coastal areas, the chemical composition of groundwater can vary depending on the intrusion of seawater, altering the adsorption distribution coefficient (Kd) values of radionuclides. This study examines the impact of seawater on the Kd values of clay minerals for cesium (Cs) and strontium (Sr). The results of Cs+ adsorption experiments showed a broad range of Kd values from 36 to 1,820 mL/g at an initial concentration of 1 mg/L and a high sorption coefficient of 15-613 mL/g at an initial concentration of 10 mg/L. Montmorillonite, hydrobiotite, illite, and kaolinite were ranked in terms of their CEC values for Cs+ adsorption, with hydrobiotite having the highest adsorption at 1 mg/L. The results of Sr adsorption experiments showed a wide range of Kd values from 82 to 1,209 mL/g at an initial concentration of 1 mg/L and a lower adsorption coefficient of 6.68-344 mL/g at an initial concentration of 10 mg/L. Both Cs+ and Sr2+ demonstrated lower Kd values at higher initial concentrations. CEC of clays found to have a significant impact on Sr2+ Kd values. Ca2+ ions showed a significant impact on Sr2+ adsorption distribution coefficients, demonstrating the greater impact of seawater on Sr2+ compared to Cs+. These findings can inform future safety assessments of radionuclides in nuclear sites.

After the Fukushima accident, significant amount of radioactively contaminated waste has been generated with 50~250 m3/day and stored in tanks of the Fukushima Daiichi nuclear power plant site. The contaminated water is treated by various treatment facility such as KURION, SARRY, Reverse Osmosis, and ALPS to remove 62 radioactive nuclides except H-3. For the contaminated water treatment process, massive secondary wastes such as sludge, spent adsorbent, and so on as by-product are being generated by the facilities. In Japan, to treat the secondary wastes, melting technologies such as GeoMelt, In-can vitrification and Cold Crucible Induction Melting vitrification are considered as a candidate technologies. In this study, the technologies were reviewed, and the advantage and disadvantage of each technology were evaluated as the candidate technologies for treatment of the secondary wastes.

When damaged nuclear fuel is stripped and re-fabricated into stabilized pellets, it is necessary to analyze the characteristics of the stabilized pellets, such as density, leaching behavior, and compressive strength, for final disposal. In this study, simulated nuclear fuel with UO2 and burn-up of 35 GWd/tU and 55 GWd/tU was used to measure the compressive strength of the stabilization pellet. In order to change the density of the sintered pellet, a sintered pellet was prepared by heat treatment at 1,550°C and 1,700°C for 6 hours in a reducing atmosphere of 4% H2/Ar. In the case of UO2, the density was 10.4 g/cm3 (94.5% of T.D.) and 10.6 g/cm3 (96.6% of T.D.) depending on the sintering temperature (1,550°C, 1,700°C). In the case of simulated fuel with a burn-up of 35 GWd/tU, the density was 8.8 g/cm3 (80.9% of T.D.) and 10.2 g/cm3 (93.6% of T.D.) depending on the sintering temperature (1,550°C, 1,700°C). In the case of simulated fuel with a burn-up of 55 GWd/tU, the density was 8.3 g/cm3 (77.0% of T.D.) and 10.0 g/cm3 (92.3% of T.D.) depending on the sintering temperature (1,550°C, 1,700°C). It was found that the compressive strength of simulated nuclear fuel decreased with increasing burn-up and increased with increasing density. In the case of UO2, the compressive strengths were 717.8 MPa and 897.4 MPa when the densities were 10.4 g/cm3 and 10.6 g.cm3, respectively. In the case of simulated nuclear fuel with a burn-up of 35 GWd/tU, the compressive strengths were 472.1 MPa and 732.3 MPa when the densities were 8.8 g/cm3 and 10.2 g/cm3. In the case of simulated nuclear fuel with a burn-up of 55 GWd/tU, the compressive strengths were 301.4 MPa and 515.5 MPa when the densities were 8.3 g/cm3 and 10.0 g/cm3, respectively.