• Steel and Composite Structures
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• v.46 no.6
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• pp.839-856
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• 2023

This work presents a simple four-unknown refined integral plate theory for mechanical and thermal buckling behaviors of functionally graded (FG) plates resting on Visco-Pasternak foundations. The proposed refined high order shear deformation theory has a new displacement field which includes indeterminate integral variables and contains only four unknowns in which any shear correction factor not used, with even less than the conventional theory of first shear strain (FSDT). Governing equations are deduced from the principle of minimum total potential energy and a Navier type analytical solution is adopted for simply supported FG plates. The Visco-Pasternak foundations is considered by adding the impact of damping to the usual foundation model which characterized by the linear Winkler's modulus and Pasternak's foundation modulus. The accuracy of the present model is demonstrated by comparing the computed results with those available in the literature. Some numerical results are presented to show the impact of material index, elastic foundation type, and damping coefficient of the foundation, on the mechanical and thermal buckling behaviors of FG plates.

• Research in Plant Disease
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• v.29 no.2
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• pp.174-183
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• 2023

The limited effectiveness of current plant disease management treatments necessitates the development of new methods for controlling diseases using beneficial microbes. Demanding sustainable agriculture is increasingly highlighted as a biocontrol approach, particularly Streptomyces species known to produce a variety of antibiotic compounds and secondary metabolites. The Streptomyces globisporus SP6C4 strain and Streptomyces sp. S8 have been reported as potent antifungal agents and are gaining attention for improving crop growth in sustainable agriculture. In this study, we investigated the use of Streptomyces species formulations to enhance bacterial growth with nitrogen sources. Specifically, the addition of L-glutamic acid and L-cysteine resulted in earlier sporulation and bacterial growth in Streptomyces strains, respectively. This approach could expand the range of fermentation techniques in agriculture and be useful for controlling plant growth-promoting bacteria.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1C
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• pp.21-31
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• 2009

Based on the proven feasibility of bottom ash and tire shred-soil mixtures as lightweight fill materials, tire shred-bottom ash mixtures were suggested as a new lightweight fill material to replace the conventional construction material (soil) with bottom ash. Therefore, we carried out the field compaction test and performance test of large scale embankment in order to evaluate their suitability for the use of lightweight fill materials. In these tests, we could assess the settlement, earth pressure, stress-strain relation, vibration of large scale embankment which were made with tire shred-bottom ash mixture and the conventional fill material(weathered soil) respectively. The earthpressure and vibration transmission was decreased and the settlement behaviour of the 2 materials (tire shred mixture and weathered soil) was measured similarly under static/cyclic loading condition.

• Journal of the Daesoon Academy of Sciences
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• v.24_1
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• pp.97-144
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• 2014

Jeungsan(甑山) carried out the Universal Redesign(天地公事) through which the former world full of a mutual opposition(相克) can be peacefully transferred into the latter world composed of a mutual beneficence(相生). Although the Universal Redesign consists of such three factors heaven, earth, and human, it converges towards Human Redesign in that humans are the main agents for heaven and earth. Human as Redesign object is characterized as a member of community, not an anarchistic individual. The Universal Resign of Jeungsan is eventually connected with the construction of a country comprising a mutual beneficence in that it is the most typical strain among all the human communities. His Universal Resign for foundering the foremost country does not target all the countries, but only one country upon and through which the world with a mutual beneficence can be formed. He executed the Universal Redesign based on such three principles as Haewon sangsaeng(解冤相生), Boeunsangsaeng(報恩相生), and Wonsibanbon(原始返本), Judging from such principles, Korea can be naturally selected as the target of the Universal Redesign for constructing the foremost country. It is approaching when the Universal Redesign in order to transform Korea into the foremost country comes true. The first step for Korea to be made as the foremost country is the construction of DMZ World Peace Park (DWPP) which was proposed by Bak Geunhye, the Korean President, to Obama, the President of USA, in 2013 she visited there. DWPP can be expected to be a center for corporation and interchange between South and North Korea under the interest and support of the world including UN, furthermore, the Capital area of reunified Korea, and finally the world hub of inter national political and economic relation. DWPP is planned to be built at the core of the best place in Korea which is a propitious spot all over the world, upon which a new world capitalism order armed with mutual beneficence can spread.

• Structural Engineering and Mechanics
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• v.88 no.2
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• pp.159-168
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• 2023

Cost-effective high precision hybrid elements are presented in a hierarchical form for dynamic analysis of plates. The costs associated with controlling the vibrations of ferromagnetic plates can be minimized by adequate determination of the amount of electric current and magnetic field. In the present study, the effect of magnetic field and electric current on nonlinear vibrations of ferromagnetic plates is investigated. The general form of Lorentz forces and Maxwell's equations have been considered for the first time to present new relationships for electromagnetic interaction forces with ferromagnetic plates. In order to derive the governing nonlinear differential equations, the theory of third-order shear deformations of three-dimensional plates has been applied along with the von Kármán large deformation strain-displacement relations. Afterward, the nonlinear equations are discretized using the Galerkin method, and the effect of various parameters is investigated. According to the results, electric current and magnetic field have different effects on the equivalent stiffness of ferromagnetic plates. As the electric current increases and the magnetic field decreases, the equivalent stiffness of the plate decreases. This is a phenomenon reported here for the first time. Furthermore, the magnetic field has a more significant effect on the steady-state deflection of the plate compared to the electric current. Increasing the magnetic field and electric current by 10-times results in a reduction of about 350% and an increase of 3.8% in the maximum steady-state deflection, respectively. Furthermore, the nonlinear frequency decreases as time passes, and these changes become more intense as the magnetic field increases.

• Journal of the Microelectronics and Packaging Society
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• v.31 no.1
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• pp.1-6
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• 2024

Spiders detect even tiny vibrations through their vibrational sensory organs. Leveraging their exceptional vibration sensing abilities, they can detect vibrations caused by prey or predators to plan attacks or perceive threats, utilizing them for survival. This paper introduces a nanoscale crack-based sensor mimicking the spider's sensory organ. Inspired by the slit sensory organ used by spiders to detect vibrations, the sensor with the cracks detects vibrations and pressure with high sensitivity. By controlling the depth of these cracks, they developed a sensor capable of detecting external mechanical signals with remarkable sensitivity. This sensor achieves a gauge factor of 16,000 at 2% strain with an applied tensile stress of 10 N. With high signal-to-noise ratio, it accurately recognizes desired vibrations, as confirmed through various evaluations of external force and biological signals (speech pattern, heart rate, etc.). This underscores the potential of utilizing biomimetic technology for the development of new sensors and their application across diverse industrial fields.

• Journal of Life Science
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• v.20 no.3
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• pp.365-373
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• 2010

To monitor newly emerged influenza virus variants and to investigate the prevalence pattern, our laboratory performed isolation of the viruses from surveillance sentinel hospitals. In the present study, we analysed influenza A/H1N1, A/H3N2, B viruses isolated in Busan during the 2006/07 and 2007/08 seasons by sequence analysis of the hemagglutinin (HA1 subunit) and neuraminidase (NA) genes. The isolates studied here were selected by the stratified random sample method from a total of 277 isolates, in which 15 were A/H1N1, 16 were A/H3N2 and 29 were B. Based on the phylogenetic tree, the HA1 gene showed that A/H1N1 isolates had a 96.7% to 97.7% homology with the A/Brisbane/59/2007, A/H3N2 isolates had a 98.4% to 99.7% homology with the A/Brisbane/10/2007, and B isolates had a 96.5% to 99.7% homology with the B/Florida/4/2006(Yamagata lineage), which are all the vaccine strains for the Northern Hemisphere in 2008~2009 season. In the case of the NA gene, A/H1N1 isolates had 97.8% to 98.5% homologies, A/H3N2 isolates had 98.9% to 99.4% homologies, and B isolates had 98.9% to 100% homologies with each vaccine strain in the 2008~2009 season, respectively. Characterization of the hemagglutinin gene revealed that amino acids at the receptor-binding site and N-linked glycosylation site were highly conserved. These results provide useful information for the control of influenza viruses in Busan and for a better understanding of vaccine strain selection.

• Composites Research
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• v.31 no.2
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• pp.51-56
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• 2018

A new study was carried out to utilize a pencil drawing paper sensor (PDPS), which drew a line using a pencil on the paper, as a sensor. The sensing effect on 3 different papers based on the properties of PDPS was compared. The specimens were prepared by drawing 4B pencils on plain (A4), Hwasun, and Han papers. The silver paste was used to give good electrical contacts of the copper wires and the pencil drawn line. The chemical structures of 3 papers for PDPS by FT-IR spectrum analysis were similar and the comparative compact states of each paper were observed by optical microscope. From statistical evaluation of tensile strength using 3 papers, plain paper was chosen to be best for the PDPD. The optimum drawing number of PDPD was determined by changing the thickness of the paper with the drawing number. Electrical resistance (ER) with graphite on 3 different papers were compared. The changes in compression was observed through cyclic compressive test of composite materials, it was possible to predict the degree of strain sensing under compressive test. It leads to expectation of properties.

• Journal of Life Science
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• v.24 no.11
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• pp.1174-1179
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• 2014

This research was carried out to evaluate whether gamma ray is a useful tool for breeding new strains of mushrooms. For this research, 5 mutant groups, 20 strains of Hypsizigus marmoreus, 2 strains of Lyophyllum decastes, and 1 strain of Lyophyllum shimeji were used. Monokaryon spores from one variety of H. marmoreus were irradiated with 50~2,000 Gy of gamma ray. The propriety dose was 50~200 Gy for mutagenesis. Mutant monokaryon mycelia crossed each order to become dikaryon mycelia. The internal transcribed spacer (ITS) regions of rDNA were amplified using PCR, and the products were sequenced. The sequences of the ITS regions (16 partial rDNA, complete ITS1, 5.8 rDNA and partial rDNA) were analyzed by PCR, and strains of H. marmoreus, L. decastes, and L. shimeji were auto-sequenced. The lengths of the sequenced ITSs were 1,052~1,143 nucleotides. Genetic matrices were calculated using Nei-Li's genetic distance coefficient based on ITS sequence. The dissimilarities were 0~3.35% in strains of H. Hypsizigus. In addition, a phylogenetic tree was constructed based on ITS sequences using the neighbor-joining (NJ) method. The phylogenetic tree revealed that 23 strains and 5 mutant groups were divided into 12 clusters; the mutant groups fell into different clusters. These results show that mushroom spores were mutated effectively by gamma ray; therefore, gamma ray could be a useful tool for breeding new strains of mushrooms.

• Journal of Sericultural and Entomological Science
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• v.33 no.1
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• pp.32-36
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• 1991

The study has been carried out to acquire some basic informations about Bacillus thuringiensis for developing the microbial pesticide. Three strains of Bacillus thuringiensis var. Kurstaki, dendrolimus and aizawai, were used in the experiments as follows. Growth characteristics of each strain were examined and parasporal protein crystals were isolated from the mixtures of spores and protein crystals by the new method of centrifugation in two-layer cushion of Renograffin using a fixed angle rotor. The results are as follows. 1. No difference was shown in growth characterestics among three strains of B. thuringiensis. In growth curves, all strains reached to exponential phase by 2 hr and stationary phase by 7-8 hr after inoculation. 2. The pH of the culture media during exponential growth stage decreased about 1.4 of a pH unit at the beginning of sporulation, but recovered during the early stage of sporulation and then remained nearly constant during the later stage. 3. As 10$m\ell$ sample was applied to two-layer cushion of Renograffin and then centrifuged for 1hr at 27,000g a fixed angle rotor, the purity and recovery ratio was 99.9% and 5.8%, respectively. It has been shown that the new method for the isolation of parasporal protein crystals was more efficient than any from the estabilished methods.