The development of thermoelectric (TE) materials to replace Bi2Te3 alloys is emerging as a hot issue with the potential for wider practical applications. In particular, layered Zintl-phase materials, which can appropriately control carrier and phonon transport behaviors, are being considered as promising candidates. However, limited data have been reported on the thermoelectric properties of metal-Sb materials that can be transformed into layered materials through the insertion of cations. In this study, we synthesized FeSb and MnSb, which are used as base materials for advanced thermoelectric materials. They were confirmed as single-phase materials by analyzing X-ray diffraction patterns. Based on electrical conductivity, the Seebeck coefficient, and thermal conductivity of both materials characterized as a function of temperature, the zT values of MnSb and FeSb were calculated to be 0.00119 and 0.00026, respectively. These properties provide a fundamental data for developing layered Zintl-phase materials with alkali/alkaline earth metal insertions.

The n-type Bi2-xSbxTe3 compounds have been of great interest due to its potential to achieve a high thermoelectric performance, comparable to that of p-type Bi2-xSbxTe3. However, a comprehensive understanding on the thermoelectric properties remains lacking. Here, we investigate the thermoelectric transport properties and band characteristics of n-type Bi2-xSbxTe3 (x = 0.1 – 1.1) based on experimental and theoretical considerations. We find that the higher power factor at lower Sb content results from the optimized balance between the density of state effective mass and nondegenerate mobility. Additionally, a higher carrier concentration at lower x suppresses bipolar conduction, thereby reducing thermal conductivity at elevated temperatures. Consequently, the highest zT of ~ 0.5 is observed at 450 K for x = 0.1 and, according to the single parabolic band model, it could be further improved by ~70 % through carrier concentration tuning.

수염풍뎅이(Polyphylla laticollis manchurica)는 과거에는 흔히 발견되었으나, 1970년대 이후 한반도 내 개체수 가 급격히 감소하여 2005년 환경부에 의해 멸종위기 야생생물 Ⅰ급으로 지정되었다. 또한 해당종의 분자생물학적 연구는 멸종위기종이라는 특성으로 인해 제한적으로 진행되었다. 그로 인해 NCBI 등 공공 데이터베이스에서 제공되는 서열정보들 또한 부족한 실정이다. 이 연구는 이러한 한계를 극복하고 수염풍뎅이의 유전적 특성을 규명하기 위해 생물정보학적 기술을 활용하여 전사체 분석을 진행하였다. Illumina HiSeq 2500 플랫폼을 사용하여 53,433,048개의 RNA reads를 얻었으며, Trinity와 TGICL을 이용한 De novo 어셈블리 분석을 통해 18,172개의 unigenes를 생성하였다. 생성된 unigenes는 GO, KOG, KEGG, PANM DB를 활용하여 annotation을 진행하였다. 그 결과, GO 분석에서는 ‘binding and catalytic activities’와 관련된 항목이 높은 발현을 보였으며, KOG 분석의 경우 ‘Cellular Processes and Signals’ 범주가 높은 비율을 나타내었다. KEGG 분석을 통해 2,118개의 unigenes가 metabolic 카테고리에 annotation된 것을 확인하였다. SSR 모티프 분석에서는 AT/AT (42.90%) 모티프, AAT/ATT (13.13%) 모티프 순으로 많이 나타나는 것을 확인하였다. 이 연구를 통해 분석한 결과 들을 이용하여 유전자원 및 종 정보를 실시간 제공 및 정보 공유가 가능하도록 Database 및 web-interface를 구축하 였으며, 이러한 자료들은 국내 멸종위기종인 수염풍뎅이의 고유한 유전적 특성을 발굴 및 확보할 수 있는 기반자 료로써 활용될 수 있을 것으로 사료된다.

장내 미생물 군집은 소화 과정, 면역 시스템, 질병 발생 등 숙주의 다양한 면에 광범위한 영향을 주는 것으로 알려져 있으며, 주요 장내 미생물 종은 숙주의 생리 기능에 핵심적인 역할을 수행한다고 발표된 바 있다. 곤충의 장내 미생물 군집에 관한 연구가 최근 활발히 이루어지고 있으며, 이들 연구는 주로 장내 미생물 군집과 기생충, 병원체 간의 상호작용, 종간의 신호 전달 네트워크, 먹이의 소화 과정 등을 중심으로 이루어지고 있다. 이러한 연구들은 대부분 Illumina MiSeq을 활용하여 16S rRNA 유전자의 V1부터 V9 영역 중 선택된 특정 부분을 대상으로 짧은 서열 정보를 대상으로 진행되었다. 그러나, 최근에는 PacBio HiFi 기술이 상용화되면서 16S rRNA의 전장 분석이 가능할 수 있게 되었다. 이번 연구는 장수말벌(Vespa mandarinia)의 해부를 통해 gut과 carcass 부분을 분리한 뒤, 각 샘플을 Illumina MiSeq과 PacBio HiFi 기술을 활용하여 미생물 군집 간의 차이점을 확인하기 위하여 수행되었다.

우리는 길앞잡이(Cicindela chinensis)의 장에서 다양한 공생 미생물들을 분리하였다. 그중 다양한 곰팡이 성장 을 억제하는 세균을 동정하였고 “Ch-1”이라 명명하였다. 우리는 Ch-1 균주를 사용하여 10종의 식물 병원성 곰팡 이와 2종 곤충 병원성 곰팡이의 생장 억제를 확인하였다. 또한 8종의 항생제에 대한 저항성을 확인하였다. 동시 에, 본 균주의 genomic sequence를 수행하였고 유전적, 생화학적, 생리적 특성을 조사하였다. Ch-1균주는 특허등 록과 친환경 미생물제제로 등록하였고 향후 생물학적 방제제로써 활용될 수 있을 것으로 판단한다.

단백질의 구조 예측은 생명 과학 및 의약학 분야의 핵심적인 연구 주제 중 하나로, 단백질의 기능 및 상호작용을 이해하기 위한 주요 정보를 제공할 수 있어 다양한 연구가 수행되고 있다. 이러한 연구의 일환으로 최근 Google DeepMind의 AlphaFold2가 등장하였으며, 단백질 구조 예측 성능을 대폭 향상시켜 CASP(Critical Assessment of Protein Structure Prediction)에서 뛰어난 평가점수를 받아 단백질 구조 예측 분야의 최신 기술을 크게 향상시켰다. 이러한 컴퓨터 기반의 단백질의 구조 예측 방법은, 고전적인 방법을 사용하여 직접 단백질 구조를 결정하는 방법 에 비해 매우 정확하고 빠르며 경제적인 비용으로 수행될 수 있어 단백질 구조 예측 및 생리학 연구를 수행하는 연구자들에게 유용한 방법론이 될 것으로 사료된다. 따라서 본 연구소에서는 곤충을 포함한 무척추 자생동물을 연구하는 연구자들을 위해 단백질 구조 예측을 수행할 수 있도록 64Core/128Threads의 CPU, 256GB의 RAM과 6장의 GeForce RTX 3090으로 이루어진 GPU(Graphical Processing Unit) 고성능 컴퓨터 시스템에 AlphaFold2 program을 구축하였다. 최근 인간을 대상으로 한 단백질 구조 예측 연구는 상당한 진전을 보이고 있지만, 곤충을 포함한 자연계의 동물을 대상으로 한 연구는 여전히 미비한 상황이다. 이러한 자생동물자원연구의 확대를 위해 본 연구소에서 구축한 GPU 시스템 및 생물정보학적 분석 방법이 많이 활용되어야 하며, 이를 위해서는 연구자들 의 협력과 참여가 필요하다.

The emergence of ferrous-medium entropy alloys (FeMEAs) with excellent tensile properties represents a potential direction for designing alloys based on metastable engineering. In this study, an FeMEA is successfully fabricated using laser powder bed fusion (LPBF), a metal additive manufacturing technology. Tensile tests are conducted on the LPBF-processed FeMEA at room temperature and cryogenic temperatures (77 K). At 77 K, the LPBF-processed FeMEA exhibits high yield strength and excellent ultimate tensile strength through active deformation-induced martensitic transformation. Furthermore, due to the low stability of the face-centered cubic (FCC) phase of the LPBFprocessed FeMEA based on nano-scale solute heterogeneity, stress-induced martensitic transformation occurs, accompanied by the appearance of a yield point phenomenon during cryogenic tensile deformation. This study elucidates the origin of the yield point phenomenon and deformation behavior of the FeMEA at 77 K.

This study examined the impact of two bacterial strains, H05E-12 and H05R- 04, on alleviating non-irrigation-induced stress and its subsequent effects on the fruit productivity of sweet pumpkin plants. When subjected to non-irrigation-induced stress, the lipid peroxidation, proline, total phenol, and total soluble sugar content significantly decreased in plants treated with either H05E-12 or H05R-04 compared to the control. In a greenhouse experiment under non-irrigated conditions, H05E-12-treated plants exhibited higher stomatal conductance than the control, although there was no significant change in the soil plant analysis development (SPAD) value due to treatment. Upon re-watering, an increase in fruit diameter was observed in H05E-12-treated plants, and the L-ascorbic acid content in the fruit also showed a significant increase compared to the control. The H05E-12 strain was identified as Kushneria konosiri. To the best of our knowledge, this is the first report detailing the beneficial effects of K. konosiri on the alleviation of non-irrigation-induced stress and the promotion of plant growth in sweet pumpkin plants.

The domestic Pressurized Heavy Water Reactor (PWHR) nuclear power plant, Wolsong Unit 1, was permanently shut down on December 24, 2019. However, research on decommissioning has mainly focused on Pressurized Water Reactors (PWRs), with a notable absence of both domestic and international experience in the decommissioning of PHWRs. If proper business management such as radiation safety and waste is not performed, it can lead to increased business risks and costs in decommissioning. Therefore, the assessment of waste volume and cost, which provide fundamental data for the nuclear decommissioning process, is a crucial technical requirement before initiating the actual decommissioning of Wolsong Unit 1. Decommissioning radiation-contaminated structures and facilities presents significant challenges due to high radiation levels, making it difficult for workers to access these areas. Therefore, technology development should precede decommissioning process assessments and safety evaluations, facilitating the derivation of optimal decommissioning procedures and ensuring worker safety while enhancing the efficiency of decommissioning operations. In this study, we have developed a program to estimate decommissioning waste amounts for PHWRs, building upon prior research on PWR decommissioning projects while accounting for the specific design characteristics of PHWRs. To evaluate the amount of radioactive waste generated during decommissioning, we considered the characteristics of radioactive waste, disposal methods, packaging container specifications, and the criteria for the transfer of radioactive waste to disposal operators. Based on the derived algorithm, we conducted a detailed design and implemented the program. The proposed program is based on 3D modeling of the decommissioning components and the calculation of the Work Difficulty Factor (WDF), which is used to determine the time weighting factors for each task. Program users can select the cutting and packaging conditions for decommissioning components, estimate waste amount based on the chosen decommissioning method, and calculate costs using time weighting factors. It can be applied not only to PHWRs, but also to PWRs and non-nuclear fields, providing a flexible tool for optimizing decommissioning process.

After the major radioactivation structures (RPV, Core, SG, etc.) due to neutron irradiation from the nuclear fuel in the reactor are permanently shut down, numerous nuclides that emit alpha-rays, beta-rays, gamma-rays, etc. exist within the radioactive structures. In this study, nuclides were selected to evaluate the source term for worker exposure management (external exposure) at the time of decommissioning. The selection of nuclides was derived by sequentially considering the four steps. In the first stage, the classification of isotopes of major nuclides generated from the radiation of fission products, neutron-radiated products, coolant-induced corrosion products, and other impurities was considered as a step to select evaluation nuclides in major primary system structures. As a second step, in order to select the major radionuclides to be considered at the time of decommissioning, it is necessary to select the nuclides considering their half-life. Considering this, nuclides that were less than 5 years after permanent suspension were excluded. As a third step, since the purpose of reducing worker exposure during decommissioning is significant, nuclides that emit gamma rays when decaying were selected. As a final step, it is a material made by radiation from the fuel rod of the reactor and is often a fission product found in the event of a Severe accident at a nuclear power plant, and is excluded from the nuclide for evaluation at the time of decommissioning is excluded. The final selected Co-60 is a nuclide that emits high-energy gamma rays and was classified as a major nuclide that affects the reduction of radiation exposure to decommissioning workers. In the future, based on the nuclide selection results derived from this study, we plan to study the evaluation of worker radiation exposure from crud to decommissioning workers by deriving evaluation results of crud and radioactive source terms within the reactor core.

Decommissioning waste is generated with various types and large quantities within a short period. Concrete, a significant building material for nuclear facilities, is one of the largest decommissioning wastes, which is mixed with aggregate, sand, and cement with water by the relevant mixing ratio. Recently, the proposed treatment method for volume reduction of radioactive concrete waste was proven up to scale-up testing using unit equipment, which involved sequentially thermomechanical and chemical treatment. According to studies, the aggregate as non-radioactive material is separated from cement components with contaminated radionuclides as less than clearance criteria, so the volume of radioactive concrete waste is decreased effectively. However, some supplementation points were presented to commercialize the process. Hence, the process requires efficiency as possible to minimize the interface parts, either by integration or rearranging the equipment. In this study, feasibility testing was performed using integrated heating and grinding equipment, to supplement the possible issue of generated powder and dust during the process. Previously, heat treatment and grinding devices were configured separately for pilot-scale testing. But some problems such as leakage and pipe blockage occurred during the transportation of generated fine powder, which caused difficulties in maintaining the equipment. For that reason, we studied to reduce the interface between the equipment by integrating and rearranging the equipment. To evaluate the thermal grinding performance, the fraction of coarse and concrete fines based on 1mm particle size was measured, and the amount of residual cement in each part was analyzed by wet analysis using 4M hydrochloric acid. The result was compared with previous studies and the thermomechanical equipment could be selected to enhance the process. Therefore, it is expected that the equipment for commercialization could be optimized and composed the process compactly by this study.

In our previous study, we developed a CFD thermal analysis model for a CANDU spent fuel dry storage silo. The purpose of this model is to reasonably predict the thermal behavior within the silo, particularly Peak Cladding Temperature (PCT), from a safety perspective. The model was developed via two steps, considering optimal thermal analysis and computational efficiency. In the first step, we simplified the complex geometry of the storage basket, which stored 2,220 fuel rods, by replacing it with an equivalent heat conductor with effective thermal conductivity. Detailed CFD analysis results were utilized during this step. In the second step, we derived a thermal analysis model that realistically considered the design and heat transfer mechanisms within the silo. We developed an uncertainty quantification method rooted in the widely adopted Best Estimate Plus Uncertainty (BEPU) method in the nuclear industry. The primary objective of this method is to derive the 95/95 tolerance limits of uncertainty for critical analysis outcomes. We initiated by assessing the uncertainty associated with the CFD input mesh and the physical model applied in thermal analysis. And then, we identified key parameters related to the heat transfer mechanism in the silo, such as thermal conductivity, surface emissivity, viscosity, etc., and determined their mean values and Probability Density Functions (PDFs). Using these derived parameters, we generated CFD inputs for uncertainty quantification, following the principles of the 3rd order Wilks’ formula. By calculating inputs, A database could be constructed based on the results. And this comprehensive database allowed us not only to quantify uncertainty, but also to evaluate the most conservative estimates and assess the influence of parameters. Through the aforementioned method, we quantified the uncertainty and evaluated the most conservative estimates for both PCT and MCT. Additionally, we conducted a quantitative evaluation of parameter influences on both. The entire process from input generation to data analysis took a relatively short period of time, approximately 5 days, which shows that the developed method is efficient. In conclusion, our developed method is effective and efficient tool for quantifying uncertainty and gaining insights into the behavior of silo temperatures under various conditions.

It has been known that as oxide layer (ZrO2) forms on the nuclear fuel cladding during irradiation in nuclear power plants, the corrosion kinetics are influenced by various parameters such as chemical environments. One of those environments, crud deposition driven by coolant chemistry has an adverse effect on the formation of oxide (ZrO2) and leads to increase thickness of the layer. In this study, crud formation was performed through loop experiment equipment on the surface of intentionally-made oxide layer (ZrO2) on cladding tubes and then the composition and characteristics of cruds were examined for the investigation of nuclear power plant environment. As a result, various cruds in composition and microstructure were formed depending on the exquisite methods and conditions such as metal ion concentration.

The thermoelectric effect, which converts waste heat into electricity, holds promise as a renewable energy technology. Recently, bismuth telluride (Bi2Te3)-based alloys are being recognized as important materials for practical applications in the temperature range from room temperature to 500 K. However, conventional sintering processes impose limitations on shape-changeable and tailorable Bi2Te3 materials. To overcome these issues, three-dimensional (3D) printing (additive manufacturing) is being adopted. Although some research results have been reported, relatively few studies on 3D printed thermoelectric materials are being carried out. In this study, we utilize extrusion 3D printing to manufacture n-type Bi1.7Sb0.3Te3 (N-BST). The ink is produced without using organic binders, which could negatively influence its thermoelectric properties. Furthermore, we introduce graphene oxide (GO) at the crystal interface to enhance the electrical properties. The formed N-BST composites exhibit significantly improved electrical conductivity and a higher Seebeck coefficient as the GO content increases. Therefore, we propose that the combination of the extrusion 3D printing process (Direct Ink Writing, DIW) and the incorporation of GO into N-BST offers a convenient and effective approach for achieving higher thermoelectric efficiency.

This study investigates social media posts on Twitter concerning cryptocurrency marketing. We applied unsupervised Latent Dirichlet Allocation (LDA) topic modeling and sentiment analysis techniques to 98,716 tweets to examine the Twitter content for subjects and sentiments related to cryptocurrency. We discovered that tweets about cryptocurrency fell into four categories, with “cryptocurrency trading,” “NFT airdrop,” “cryptocurrency affiliate program,” and “Dogecoin on social media” being the most popular. Most of the topics had positive sentiments. Theoretical and practical implications for developing cryptocurrency marketing communication strategies are discussed.

This study was conducted to examine the effect of a diet supplemented with dried Bacillus subtilis culture on broilers' productivity and blood characteristics. Broiler feeding experiments were conducted twice. The diet fed to the control group was supplemented with 0.2% Palm MateⓇ commercially available probiotics (B. subtilis), and the diet fed to the experimental group was supplemented with ThekerⓇ 0.05% dried B. subtilis culture (DBC) in experiment 1, and 0.1% DBC in experiment 2. Treatment was administered for four weeks in both groups. A higher average daily gain was observed in the group treated with 0.05% DBC in experiment 1 compared with the control group, which was significantly higher in the group that received 0.1% DBC in experiment 2 compared with the control group. A higher production index was observed in the groups that received treatment than in the control group and was higher in the 0.1% DBC group than in the 0.05% DBC group. Significantly lower serum triglyceride (TG) was observed with increased DBC content. Although the findings showed no statistical significance, lower total cholesterol (T-C) was observed in the treated group than in the control group. HDL-cholesterol (HDL-C) content showed a significant increase in the DBC-treated groups. A significantly opposite outcome was observed for LDL-cholesterol (LDL-C) content. These findings demonstrated that the atherogenic index (AI) and cardiac risk factor (CRF) decreased in the DBC-treated groups. Significantly lower serum levels of glutamic-oxaloacetic transaminase (GOT: aspartate aminotransferase, AST) and glutamate pyruvic transaminase (GPT: alanine transaminase, ALT) were detected with an increase in DBC content in the treated groups compared with the control groups. To summarize the findings described above, adding ThekerⓇ dried B. subtilis culture to broiler feeds positively improved productivity through weight gain of broilers and the production of healthier functional broilers through the improvement of blood lipids and liver function. It is expected that the findings of this study will be helpful in the effort to increase the profitability of broiler chicken farming and promote human health.