• 자원환경지질
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• 제55권3호
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• pp.273-280
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• 2022

본 연구의 목적은 빅데이터 분석을 활용한 지질자원기술에 대한 사회적 인식을 바탕으로 지질자원기술에 대한 국민 인식 제고 방안을 논의하는 데 있다. 이를 위하여 2010년 1월 1일부터 2022년 4월 14일까지 54개 언론사를 대상으로 언론 기사 제목과 본문에 '지질자원기술'이 포함된 5,044건의 기사를 분석대상으로 삼았으며, 빅데이터 분석을 연구방법으로 채택하였다. 분석 결과, 연구소 중심, 미국·중국·일본 중심, 포항시 지진, 연구원 원장 중심으로 주제어가 구성되어 있었으며, 중요 주제어는 지질, 산업, 광물개발, 환경, 에너지, 원자력, 지하수 등으로 나타났다. 또한, 토픽 분석 결과, 토픽들은 개별적으로 위치하지 않고 전문가, 환경, 연구소 등을 중심으로 상호 연계되어 있고, 미래, 산업, 글로벌 토픽 등으로 확인되었다. 이러한 결과를 바탕으로 지질자원기술의 국민 인식 제고 방안을 논의하였다.

• Tribology and Lubricants
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• 제38권3호
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• pp.73-83
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• 2022

This paper is concerned with an analysis of a surface edge crack emanated from a sharp contact edge. For a geometrical model, a square wedge is in contact with a half plane whose materials are identical, and a surface perpendicular crack initiated from the contact edge exists in the half plane. To analyze this crack problem, it is necessary to evaluate the stress field on the crack line which are induced by the contact tractions and pseudo-dislocations that simulate the crack, using the Bueckner principle. In this Part I, the stress filed in the half plane due to the contact is re-summarized using an asymptotic analysis method, which has been published before by the author. Further focus is given to the stress field in the half plane due to a pseudo-edge dislocation, which will provide a stress solution due to a crack (i.e. a continuous distribution of edge dislocations) later, using the Burgers vector. Essential result of the present work is the corrective functions which modify the stress field of an infinite domain to apply for the present one which has free surfaces, and thus the infiniteness is no longer preserved. Numerical methods and coordinate normalization are used, which was developed for an edge crack problem, using the Gauss-Jacobi integration formula. The convergence of the corrective functions are investigated here. Features of the corrective functions and their application to a crack problem will be given in Part II.

• Tribology and Lubricants
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• 제38권3호
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• pp.84-92
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• 2022

In Part I, developed was a method to obtain the stress field due to an edge dislocation that locates in an elastic half plane beneath the contact edge of an elastically similar square wedge. Essential result was the corrective functions which incorporate a traction free condition of the free surfaces. In the sequel to Part I, features of the corrective functions, F_kij,(k = x, y;i,j = x,y) are investigated in this Part II at first. It is found that F_xxx(ŷ) = F_xyx(ŷ) where ŷ = y/η and η being the location of an edge dislocation on the y axis. When compared with the corrective functions derived for the case of an edge dislocation at x = ξ, analogy is found when the indices of y and x are exchanged with each other as can be readily expected. The corrective functions are curve fitted by using the scatter data generated using a numerical technique. The algebraic form for the curve fitting is designed as F_kij(ŷ) = $\frac{1}{\hat{y}^{1-{\lambda}}I+yp}$$\sum_{q=0}^{m}{\left}$$\left[A_q\left(\frac{\hat{y}}{1+\hat{y}} \right)^q \right]$ where λ_I=0.5445, the eigenvalue of the adhesive complete contact problem introduced in Part I. To investigate the exponent of F_kij, i.e.(1 - λ_I) and p, Log|F_kij|(ŷ)-Log|(ŷ)| is plotted and investigated. All the coefficients and powers in the algebraic form of the corrective functions are obtained using Mathematica. Method of analyzing a surface perpendicular crack emanated from the complete contact edge is explained as an application of the curve-fitted corrective functions.

• 한국분말재료학회지
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• 제29권1호
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• pp.22-27
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• 2022

Conventionally, metal materials are produced by subtractive manufacturing followed by melting. However, there has been an increasing interest in additive manufacturing, especially metal 3D printing technology, which is relatively inexpensive because of the absence of complicated processing steps. In this study, we focus on the effect of varying powder size on the synthesis quality, and suggest optimum process conditions for the preparation of AlCrFeNi high-entropy alloy powder. The SEM image of the as-fabricated specimens show countless, fine, as-synthesized powders. Furthermore, we have examined the phase and microstructure before and after 3D printing, and found that there are no noticeable changes in the phase or microstructure. However, it was determined that the larger the powder size, the better the Vickers hardness of the material. This study sheds light on the optimization of process conditions in the metal 3D printing field.

• Wind and Structures
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• 제34권5호
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• pp.395-405
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• 2022

Tornado-induced damages to high-rise buildings and low-rise buildings are quite different in nature. Tornado losses to high-rise buildings are generally associated with building envelope failures while tornado-induced damages to low-rise buildings are usually associated with structural or large component failures such as complete collapses, or roofs being torn off. While studies of tornado-induced structural damages tend to focus mainly on low-rise residential buildings, transmission towers, or nuclear power plants, the current rapid expansion of city centers and development of large-scale building complexes increases the risk of tornadoes impacting tall buildings. It is, therefore, important to determine how tornado-induced load affects tall buildings compared with those based on synoptic boundary layer winds. The present study applies an experimentally simulated tornado wind field to the Commonwealth Advisory Aeronautical Research Council (CAARC) building and estimates and compares its pressure coefficient effects against the Atmospheric Boundary Layer (ABL) flow field. Simulations are performed at the Wind Engineering, Energy and Environment (WindEEE) Dome which is capable of generating both ABL and tornadic winds. A model of the CAARC building at a scale of 1:200 for both ABL and tornado flows was built and equipped with pressure taps. Mean and peak surface pressures for TLV flow are reported and compared with the ABL induced wind for different time-averaging. By following a compatible definition of the pressure coefficients for TLV and ABL fields, the resulting TLV pressure field presents a similar trend to the ABL case. Also, the results show that, for the high-rise building model, the mean and 3-sec peak pressures are larger for the ABL case compared to the TLV case. These results provide a way forward for the code implementation of tornado-induced pressures on high-rise buildings.

• Journal of Veterinary Science
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• 제23권5호
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• pp.72.1-72.14
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• 2022

Background: The treatment of acute kidney injury (AKI), a common disease in dogs, is limited. Therefore, an effective method to prevent AKI in veterinary clinics is particularly crucial. Objectives: Hydrogen sulfide (H₂S) is the third gaseous signal molecule involved in various physiological functions of the body. The present study investigated the effect of H₂S on cisplatin-induced AKI and the involved mechanisms in dogs. Methods: Cisplatin-injected dogs developed AKI symptoms as indicated by renal dysfunction and pathological changes. In the H₂S-treated group, 50 mM sodium hydrosulfide (NaHS) solution was injected at 1 mg/kg/h for 30 min before cisplatin injection. After 72 h, tissue and blood samples were collected immediately. We performed biochemical tests, optical microscopy studies, analysis with test kits, quantitative reverse-transcription polymerase chain reaction, and western blot analysis. Results: The study results demonstrated that cisplatin injection increased necroptosis and regulated the corresponding protein expression of receptor interacting protein kinase (RIPK) 1, RIPK3, and poly ADP-ribose polymerase 1; furthermore, it activated the expressions of inflammatory factors, including tumor necrosis factor-alpha, nuclear factor kappa B, and interleukin-1β, in canine kidney tissues. Moreover, cisplatin triggered oxidative stress and affected energy metabolism. Conversely, an injection of NaHS solution considerably reduced the aforementioned changes. Conclusions: In conclusion, H₂S protects the kidney from cisplatin-induced AKI through the mitigation of necroptosis and inflammation. These findings provide new and valuable clues for the treatment of canine AKI and are of great significance for AKI prevention in veterinary clinics.

• 한국해안·해양공학회논문집
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• 제34권6호
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• pp.211-221
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• 2022

파의 처오름높이는 제방, 호안 및 방파제와 같은 해안 구조물의 설계에 영향을 미치는 가장 중요한 매개변수 중 하나이다. 본 연구에서는 비정수압 수치모형인 SWASH(Zijlema et al., 2011)를 이용해 고정된 수중 및 부유식 사각형 구조물에 의한 고립파의 처오름높이 저감 효과를 분석하였다. SWASH 수치모형이 고립파의 전파, 쇄파 및 처오름현상을 매우 잘 재현하는 것을 확인하였다. 또한 수중 및 부유식 사각형 구조물에 의한 고립파의 파랑변형을 잘 재현하는 것을 확인하였다. 마지막으로 수중 및 부유식 사각형 구조물의 처오름높이 저감 효과를 검토하였다. 부유식 구조물의 에너지 감쇠효과는 수중 구조물보다 크고, 처오름높이 저감에 더 효과적인 것으로 나타났다.

• Structural Engineering and Mechanics
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• 제86권3호
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• pp.291-309
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• 2023

This paper addresses the finite element modeling of functionally graded porous (FGP) beams for free vibration and buckling behaviour cases. The formulated finite element is based on simple and efficient higher order shear deformation theory. The key feature of this formulation is that it deals with Euler-Bernoulli beam theory with only three unknowns without requiring any shear correction factor. In fact, the presented two-noded beam element has three degrees of freedom per node, and the discrete model guarantees the interelement continuity by using both C⁰ and C¹ continuities for the displacement field and its first derivative shape functions, respectively. The weak form of the governing equations is obtained from the Hamilton principle of FGP beams to generate the elementary stiffness, geometric, and mass matrices. By deploying the isoparametric coordinate system, the derived elementary matrices are computed using the Gauss quadrature rule. To overcome the shear-locking phenomenon, the reduced integration technique is used for the shear strain energy. Furthermore, the effect of porosity distribution patterns on the free vibration and buckling behaviours of porous functionally graded beams in various parameters is investigated. The obtained results extend and improve those predicted previously by alternative existing theories, in which significant parameters such as material distribution, geometrical configuration, boundary conditions, and porosity distributions are considered and discussed in detailed numerical comparisons. Determining the impacts of these parameters on natural frequencies and critical buckling loads play an essential role in the manufacturing process of such materials and their related mechanical modeling in aerospace, nuclear, civil, and other structures.

• 유기물자원화
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• 제31권3호
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• pp.65-71
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• 2023

원자력 발전소에서 유출되는 세슘은 인체의 유해성으로 인하여, 이를 안전하게 처리하는 기술이 요구되고 있다. 본 연구에서는 수용액에 용해된 세슘을 효율적으로 제거하고자, triethylenediamine (TEDA) 첨착 공정을 활성탄소에 적용하였다. 이 실험에서는 활성탄소 표면을 다양한 TEDA(2.5, 5.0, 7.5, 10.0, 12.5%) 농도로 화학적 개질을 하였으며, 세슘 제거효율 평가에 의하여 최적의 TEDA 농도가 5.0%임을 구할 수 있었다. 또한, 5.0% TEDA로 첨착된 활성탄을 사용하여 5.0과 10.0 mg/L의 세슘을 처리하였을 때, 제거효율은 각각 71.5%와 61.1%를 나타내었다. 그리고 온도 변화에 의한 흡착동력학 실험으로부터, 화학적 흡착이 이루어짐을 알 수 있었다. 이 연구를 통하여 얻어진 새로운 복원 기술은 지표수와 지하수에 함유된 세슘을 실용적으로 제거하는데 사용될 수 있을 것이다.

• Mycobiology
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• 제50권5호
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• pp.374-381
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• 2022

In the mating of filamentous basidiomycetes, dikaryotic mycelia are generated through the reciprocal movement of nuclei to a monokaryotic cytoplasm where a nucleus of compatible mating type resides, resulting in the establishment of two different dikaryotic strains having the same nuclei but different mitochondria. To better understand the role of mitochondria in mushrooms, we created four sets of dikaryotic strains of Lentinula edodes, including B2×E13 (B2 side) and B2×E13 (E13 side), B5×E13 (B5 side) and B5×E13 (E13 side), E8×H3 (E8 side) and E8×H3 (H3 side), and K3×H3 (K3 side) and K3×H3 (H3 side). The karyotypes and mitochondrial types of the dikaryotic strains were successfully identified by the A mating type markers and the mitochondrial variable length tandem repeat markers, respectively. Comparative analyses of the dikaryotic strains on the mycelial growth, substrate browning, fruiting characteristics, and mitochondrial gene expression revealed that certain mitochondria are more effective in the mycelial growth and the production of fruiting body, possibly through the activated energy metabolism. Our findings indicate that mitochondria affect the physiology of dikaryotic strains having the same nuclear information and therefore a selection strategy aimed at mitochondrial function is needed in the development of new mushroom strain.