As a method to understand the ecological habits around the artificial reef, various reports such as fishing gear survey, diving, sound survey, underwater CCTV and camera, etc. are reported. Among them, the sound survey method is carried out by installing an acoustic system on the ship and can be investigated regardless of the marine environment such as time constraints and turbidity. Such method, however, takes a lot of manpower and time as the ship travels at a constant speed. Investigations around artificial reefs are being conducted in an artificial way, and a lot of time and labor are consumed as such. Maritime buoys have been operated for various purposes such as route signs, weather observation, marine environment monitoring and defense monitoring for navigation safety in the past, but studies on monitoring systems for ecological habits and distribution of fish using marine buoys are remarkably insufficient. Therefore, this study aims to develop a system that allows users to directly monitor fish group detector data by estimating the distribution of fish groups around artificial reefs and using wireless communication at sea. In order to confirm the suitability of the maritime buoy used in this study, it was operated to compare data using LTE-equipped buoys capable of wireless communication and a data logger-type system buoy. Data transmission of buoys capable of LTE communication was carried out in a 10-minute ON, 10-minute OFF method due to the limitation of the power supply capacity, and data of the data logger-type buoy received full data. We compared and analyzed the data received from the two fish detectors. It is expected that real-time monitoring of the wireless buoy detection device using LTE will be possible through future research.

Polyoxometalates (POMs) are nanoclusters composed of transition metals with high oxidation states. Owing to their redox properties and structural diversity, POMs have been applied to broad fields, such as catalysis, materials, and medicine. Among various fields of application, POMs play an important role in radiochemistry. POMs can form complexes with tri- and tetravalent lanthanides and actinides (radioactive elements), which may be good sequestrators or agents for separating nuclear wastes. Among the most prominent POM structures, Anderson-type POMs with a general formula of [Hy(XO6)M6O18]n− (y=0–6, n=2–8, M=addenda atom, X=heteroatom) represent one of the basic topological structures of the POM family. An important feature of Anderson type POMs is incorporating a large number of various heteroatoms with different size and oxidation states, which can lead to tune chemical properties. Interestingly, no example of Anderson type POMs with early transition metal ions in the heteroatom site has been reported to date. Herein, we discovered that the Anderson POM Na2K6Ti0.92W6.08O24·12H2O, which consists of pure inorganic framework built from a central Ti core supported by six WO6 inorganic scaffold, and the crystal structure was confirmed and refined using single-crystal X-ray diffraction (SC-XRD). In addition, structural characterizations, including, Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and Inductively coupled plasma-optical emission spectroscopy (ICP-OES) were performed.

Deep geologic disposal of high-level nuclear wastes (HLW) requires intensive monitoring instrumentations to ensure long-term security. Acoustic emission (AE) method is considered as an effective method to monitor the mechanical degradation of natural rock and man-made concrete structures. The objectives of this study are (a) to identify the AE characteristics emitted from concretes as concrete materials under different types of loading, (b) to suggest AE parametric criteria to determine loading types and estimate the failure stage, and finally (c) to examine the feasibility of using AE method for real-time monitoring of geologic disposal system of HLW. This study performs a series of the mechanical experiments on concrete samples simultaneously with AE monitoring, including the uniaxial compression test (UCT), Brazilian tensile test (BTT) and punch through shear test (PTST). These mechanical tests are chosen to explore the effect of loading types on the resulting AE characteristics. This study selects important AE parameters which includes the AE count, average frequency (AF) and RA value in the time domain, and the peak frequency (PF) and centroid frequency in the frequency domain. The result reveals that the cumulative AE counts, the maximum RA value and the moving average PF show their potentials as indicators to damage progress for a certain loading type. The observed trends in the cumulative AE counts and the maximum RA value show three unique stages with an increase in applied stress: the steady state stage (or crack initiation stage; < 70% of yield stress), the transition stage (or damage progression stage; 70–90% of yield stress) and the rising stage (or failure stage; > 90% of yield stress). In addition, the moving average PF of PTST in the early damage stage appears to be particularly lower than that of UCT and BTT. The loading in BTT renders distinctive responses in the slope of the maximum RA–cumulative AE count (or tan ). The slope value shows less than 0.25 when the stress is close to 30% of BTT, 60% of UCT and 75% of PTST and mostly after 90% of yield stress, the slope mostly decreases than 0.25 in all tests. This study advances our understanding on AE responses of concrete materials with well-controlled laboratoryscale experimental AE data, and provides insights into further development of AE-base real-time diagnostic monitoring of structures made of rocks and concretes.

The Na, Al, and Si akoxides-based sorbents for iodine capture have higher maximum iodine capture capacity and pore properties than zeolite-based sorbents. However, these sorbents were prepared in the form of granules via a step for cutting cylindrical alcogels. Since as-made sorbents decreased packing density, they must be additionally crushed and then classified into an appropriate size for increasing packing density. The bead formation in the step of sol-gelation could bring about the simplification of sorbent fabrication process and an improvement of packing density. For the formation of gel bead, characteristics such as hydrophilic or hydrophobic property and density of sol solution were investigated to design sol-gelation equipment. The sol-gel bead preparation equipment in the reflection of sol solution characteristics was fabricated through selection of oil for formation of sol bead, solvent for collection of gel bead, and nozzle for spray of sol droplet formation. The continuous or discontinuous formation of sol beads from NaAlSi-OH sol solution were observed according to flow rates of 6 to 8 mL·min−1 and nozzle diameters of 0.4 to 0.8 mm. In the sphericity of sol bead, the best sol beads were obtained from 0.5 mm nozzle without clogging by sol solution in the flow rate range of 6–8·min−1.

Using I-band images of 35 nearby (z < 0.1) type 1 active galactic nuclei (AGNs) obtained with Hubble Space Telescope, selected from the 70-month Swift-BAT X-ray source catalog, we investigate the photometric properties of the host galaxies. With a careful treatment of the point-spread function (PSF) model and imaging decomposition, we robustly measure the I-band brightness and the effective radius of bulges in our sample. Along with black hole (BH) mass estimates from single-epoch spectroscopic data, we present the relation between BH mass and I-band bulge luminosity (MBH–MI,bul relation) of our sample AGNs. We find that our sample lies offset from the MBH–MI,bul relation of inactive galaxies by 0.4 dex, i.e., at a given bulge luminosity, the BH mass of our sample is systematically smaller than that of inactive galaxies. We also demonstrate that the zero point offset in the MBH–MI,bul relation with respect to inactive galaxies is correlated with the Eddington ratio. Based on the Kormendy relation, we find that the mean surface brightness of ellipticals and classical bulges in our sample is comparable to that of normal galaxies, revealing that bulge brightness is not enhanced in our sample. As a result, we conclude that the deviation in the MBH–MI,bul relation from inactive galaxies is possibly because the scaling factor in the virial BH mass estimator depends on the Eddington ratio.

Valves are one of the indispensable components in modern industry. Filling and de-pressure connectors in rocket valves used for space launch vehicles are very important parts for smooth fluid supply. For this reason, an optimized design that can improve efficiency, miniaturization, weight reduction, and safety of the valve at the same time is required. In this work, flow analysis and structural analysis were performed through 3D modeling using computational numerical analysis for open type filling and de-pressure valves. As results, the flow velocity and pressure distribution of the fluid were analyzed through the flow analysis of valve, and stress distribution was conducted in structural analysis. Through this study, it is consequently expected to provide valves of various specifications by performing production and performance test evaluation of development prototypes.

The CoCrFeMnNi high-entropy alloy (HEA), which is the most widely known HEA with a single facecentered cubic structure, has attracted significant academic attention over the past decade owing to its outstanding multifunctional performance. Recent studies have suggested that CoCrFeMnNi-type HEAs exhibit excellent printability for selective laser melting (SLM) under a wide range of process conditions. Moreover, it has been suggested that SLM can not only provide great topological freedom of design but also exhibit excellent mechanical properties by overcoming the strength–ductility trade-off via producing a hierarchical heterogeneous microstructure. In this regard, the SLM-processed CoCrFeMnNi HEA has been extensively studied to comprehensively understand the mechanisms of microstructural evolution and resulting changes in mechanical properties. In this review, recent studies on CoCrFeMnNi-type HEAs produced using SLM are discussed with respect to process-induced microstructural evolution and the relationship between hierarchical heterogeneous microstructure and mechanical properties.

In this study, a comparative dissolution experiment was conducted between an immediate-release and a controlled-release vitamin C tablet applied with a technology to control the dissolution of vitamin C to maintain the vitamin C level in the human body. In order to confirm the dissolution rate (%) of vitamin C tablets, HPLC determination was conducted based on the dissolution test methods in the ‘Korean Pharmacopoeia (No. 2020-88),’ ‘Guidelines on Specifications of Dissolution Tests for Oral dosage Forms,’ and ‘Standard and Specifications for Health Functional Foods (No. 2020-63)’ from Ministry of Food and Drug Safety (MFDS). In addition, the dissolution pattern between the immediate-release tablet and the controlled-release tablet was comparatively analyzed. The analysis result confirmed that the immediate-release vitamin C tablet was 100% dissolved after 45 minutes, while the controlled- release vitamin C tablet was 100% dissolved after 480 minutes (8 hours). Furthermore, the dissolution rate (%) at 60 minutes was slower than that of the immediate-release vitamin C tablet. Based on these results, this study confirmed that the dissolution rate (%) test and development of controlled-release tablets containing vitamin C as the main component a re possible.

본 논문에서는 한국의 서남해상에 건설예정인 해상풍력발전타워의 지지구조물로 고려되고 있는 세발구조와 자켓구조의 선박충 돌 거동을 비선형동적해석을 통하여 비교‧분석하였다. 이 구조물은 3MW용량의 풍력타워를 지지하기 위하여 설계되었다. 두 지지구 조는 쉘요소를 이용하여 비선형 거동을 고려할 수 있도록 모델링하였고, 발전기를 포함하는 상부의 타워구조물은 탄성재료를 이용하 여 보요소와 집중질량으로 모델링하였다. 전체 질량은 세발구조가 자켓구조에 비하여 약 1.66배 정도였다. 바지선과 상선을 충돌선박 으로 선정하여 모델링하였다. 조수차의 조건을 고려하여 충돌선박의 충돌위치를 평균해수면의 상하로 3.5m변동하는 것으로 고려하 였다. 또한 각 선박의 최소충돌속도(=2.6m/s)에서의 충돌에너지를 각각 4배까지 증가시키면서 충돌거동을 산정하였다. 해석결과 지 지구조 충돌부위의 강성이 클수록 선박의 소성에너지 소산량이 상대적으로 증가하였다. 충돌조건에 따라 풍력타워의 변형은 진동에 서 붕괴까지 발생하였다. 세발구조가 자켓구조에 비하여 큰 충돌저항력을 보였다. 이는 중앙부에 강성이 집중된 구조적 특성과 상대 적으로 많은 강재의 사용량에 기인한 것으로 판단된다.

본 연구는 에니어그램 배형의 중소기업 경영자가 인식하는 리더십 유형과 특 성을 파악하기 위해 과학적으로 주관적인 의미를 측정할 수 있는 Q 방법론을 활용하여 분석하였다. 인터뷰와 선행연구를 통하여 200개의 Q모집단을 구성한 다음 40개의 진술문으로 Q 표본으로 선정하였다. 연구에 사용된 P샘플은 중소 기업 경영자 중 에니어그램 배형 23명을 선정하여 Q분류 과정을 통해 나온 자 료를 QUANL 프로그램을 사용하여 주성분 요인 분석을 실시하였다. 연구결과 유형 1은 ‘팔로워의 성장을 돕는 비전제시형’ 유형 2는 ‘팔로워에 대한 책임감이 강한 외강내유형’ , 유형 3은 ‘일보다 사람이 우선인 팔로워중심형’, 유형 4는 ‘팔 로워에게 모범이 되는 자기관리형’으로 나타났다. 이상의 연구 결과를 통하여 에니어그램 배형의 중소기업 경영자가 인식하는 리더십을 유형별로 확인할 수 있었으며, 유형별 특성을 통해서 에니어그램 배형 중소기업 경영자의 특성을 이 해하는데 기초 자료를 제공하였다는 점에서 의의가 있다.