• Tribology and Lubricants
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• v.21 no.3
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• pp.136-141
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• 2005

Analytical model to calculate the contact fatigue life of rough surface is presented in this paper. The effect of surface roughness can be calculated by this model. Computational method and the theoretical basis are also discussed. Contact stresses are obtained by contact analysis of a semi-infinite solid based on the use of influence functions; the subsurface stress field is obtained using rectangular patch solutions. Mesoscopic multiaxial fatigue criterion which can yield satisfactory results for non-proportional loading is then applied to predict fatigue damage. Suitable counting method and damage rule were used to calculate the fatigue life of random loading caused by rough surface. As a result of analysis the relationship between the life and the roughness as well as the most probable depth of the crack initiation is calculated.

• Journal of Welding and Joining
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• v.7 no.4
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• pp.22-29
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• 1989

In this paper weld distortion both in butt and fillet welds by flux cored arc welding has been investigated by changing welding parameters such as heat input and plate thickness, and the weld distortion was expressed as a function of welding parameters adopting the inherent strain theory as proposed by Watanabe and Satoh in 1961. As results of the research it is proposed that transverse shrinkage in root pass butt welds in proportional to ln[(Q/t_-tan.theta.] where Q is heat input(cal/mm), t is plate thickness(mm), and 2.theta. is groove angle(degree), and angular distortion .phi.(radian) in one pass of fillet welds has the following relationship: .phi..var.(Q/ $t^{1.5}$)$^{3}$exp[-(Q/ $t^{1.5}$ )$^{2}$3/] These equations provide us with basic tools to predict the amount of weld distortion in welded structures.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.3
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• pp.177-185
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• 1999

In this study, study about fly ash and blast-furnace slag used as substitutive materials for cement, and the influence on the neutralization of high flow concrete durability with these substitutive materials was performed and analyzed. The results are as follows 1) Aggregate segregation was partially improved with the progress of the admixture input at the mix proportion above slump flow 65 cm 2) Compressive strength with the progress of the increasement of fly ash input was decreased in early age, but decrease range was improved in long term age. Also, in case of blast-furnace, similar or improved compressive strength was appeared. 3) The neutralization depth with fly ash input was noticeably increased. But blast-furnace slag was effective to prevent. 4) In this experiment, high powder content was advantageously affected on preventive effect of the neutralization, and the relationship between the compressive strength and the neutralization depth was inversely proportional.

• Advances in aircraft and spacecraft science
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• v.3 no.1
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• pp.45-59
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• 2016

In this paper, the condensation method which is based on the Rayleigh-Ritz method, is described for the free vibration analysis of axially loaded slightly curved beams subject to partial axial restraints. If the longitudinal inertia is neglected, some of the Rayleigh-Ritz minimization equations are independent of the frequency. These equations can be used to formulate a relationship between the weighting coefficients associated with the lateral and longitudinal displacements, which leads to "connection coefficient matrix". Once this matrix is formed, it is then substituted into the remaining Rayleigh-Ritz equations to obtain an eigenvalue equation with a reduced matrix size. This method has been applied to simply supported and partially clamped beams with three different shapes of imperfection. The results indicate that for small imperfections resembling the fundamental vibration mode, the sum of the square of the fundamental natural and a non-dimensional axial load ratio normalized with respect to the fundamental critical load is approximately proportional to the square of the central displacement.

• Journal of Plant Biology
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• v.6 no.4
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• pp.1-4
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• 1963

Using conidia of Neurospora, changes in respiratory activities and the sensitivity to the ultraviolet light of the cells at different growing stages were measured by manometric methods, and the correlation between them was observed. Efficiency in the utilization of various carbon sources, such as, glucose, sucrose, maltose, starch and sodium acetate, in growth and exogenous respiration of N. crassa was also determined. Growth rate of N. crassa was decreased considerably in the medium containing sodium acetate than in the glucose medium and was almost zero in the lactose medium, whereas the utilization of sucrose, maltose and starch was ve교 high, as that of glucose. Respiratory activities of the cells veried considerably depending upon their different growing stages. Actively growing hyphae exhibited the greatest activity in exogenous glucose respiration, followed by germinating and activated conidia in decreasing order. There was no proportional relationship between the dose of ultraviolet light irradiated and its effect on the respiratory activity of the cells, though the more the dose of ultraviolet light, the more the injury. The sensitivity of the cells to ultraviolet light varied with the different respiratory activities of the cells linked to the developmental stages. In general, the more actively growing cells having high respiratory activities exhibited the more serious injury.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.3
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• pp.29-36
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• 2018

In this study, the moisture contents of four Hanoks have been monitored and the results were analyzed. Murujeong and Ongojae were built by traditional construction method and material, and Jeeshinjae and Hwakyeongdang were built by modernized construction method and material. Hwakyeongdang was monitored about 2 years and 9 months and the other three Hanoks were monitored about 4 years and 2 months. The surface moisture contents were measured by the non-destructive electronic resistant type moisture content meter. The measured moisture contents were affected by the orientation to the sun, wood type, temperature and relative humidity. The columns on the northern side and lumber showed more moisture contents than those of the southern side and glue-laminated wood. The moisture contents and relative humidity showed proportional relationship. The moisture contents of all four monitored Hanoks existed proper range by and large.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.4_1
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• pp.411-419
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• 2021

In this study, IGBT_Total_Loss and DIODE_Total_Loss were used to analyze the slope of the junction temperature for each section for temperature and duty variables in order to simply calculate the junction temperature of the power semiconductor (IGBT). As a result of the calculation, IGBT_Max_Junction_Temp and DIODE_Max_Junction_Temp form a proportional relationship with temperature for each duty. This simulation data shows that the power loss of a power semiconductor is calculated in a complex manner according to the current dependence index, voltage dependence index, and temperature coefficient. By applying the slope for each condition and section, the junction temperature of the power semiconductor can be calculated simply.

• Journal of the Korea Safety Management & Science
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• v.25 no.2
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• pp.187-192
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• 2023

In piping systems, trapeze hangers are subjected to vertical and horizontal seismic loads and stiffeners are used. In this study, monotonic compression tests were conducted with the removable stiffeners using three variables: stiffener clamp fixing position, section length, and installation direction. The maximum load reinforced with stiffeners could withstand a compressive load of 11kN by applying a safety factor of 10%. It could be estimated that the fixing clamp spacing or the length of shape and load had a proportional relationship. And the stiffener must be fixed in the direction of the strong axis on hinge parts. Also the stiffener buckiling load design proposes to use a method of calculate the flexural buckling compressive strength of and unreinforced full threaded bolt.

• Publications of The Korean Astronomical Society
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• v.23 no.2
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• pp.123-128
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• 2008

Productivity of the Giant Magellan Telescope is estimated based on the annual number of papers produced by the currently operating large telescopes such as the telescope at the ESO La Silla observatory, CFHT, AAT, the Magellan telescopes, ESO VLT, Japanese Subaru, the Gemini telescopes, and the Keck telescopes. We find that the amount of papers produced by a large telescope is roughly proportional to the diameter of its primary mirror. With this fact, we estimate the SCI-paper productivity of the Giant Magellan Telescope by extrapolating the productivity of the above-mentioned large telescopes. Moreover, according to the paper written in 2001 by Benn and Sanchez, the amount of highly-cited papers produced by a large telescope is roughly proportional to the light-gathering power of the telescope or the square of the diameter. Hence, we survey the productivity of Nature-class papers of the large telescopes and extrapolate the relationship to estimate the productivity of the Nature-class papers by using the Giant Magellan telescope of a filled aperture 21.4 meters in diameter. We expect that Korean astronomers will be able to produce annually 60 SCI-class papers and 20 Nature-class papers with high scientific impact by using the telescope-time corresponding to the 10% share of the Giant Magellan Telescope.

• Korean Journal of Agricultural Science
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• v.18 no.1
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• pp.41-48
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• 1991

Rheological properties of gelatinized potato starch were investigated with Brookfield wide-gap viscometer at various conditions. The gelatinized potato starch at 3-7% showed a pseudoplastic behavior with yield stress, and presented thixotropic properties with time-dependent structural decays. The consistency index and yield stress of gelatinized starch were proportional to starch concentration but inversely proportional to measurement temperature, and the flow behavior index did not show constant relationship. The consistency index and yield stress of the gelatinized starch on addition of phosphate decreased as the flow behavior index increased. The values of activation energy at initial and equilibrium were 1.52 kcal/g.mole and 127 kcal/g.mole, respectively.