• Journal of Welding and Joining
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• v.32 no.2
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• pp.63-69
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• 2014

Dual laser heat sources were used for polymer based material joining. An infrared camera and thermocouple DAQ system were used to correlate the temperature distribution to computer simulation. A 50 degree tilted pre-heating laser source was acting as a heating source to promote the temperature to minimize thermal shock by the following a welding heat source. Based on the experimental result, the skin depth was empirically estimated for computer simulation. The offsets of 3mm, 5mm and 10mm split by weld and preheat were effectively used to control the temperature distribution for the optimal laser joining process. The closer offset resulted in an excessive melting or burning caused by sudden temperature rising. The laser power was split by 50%, 75% and 100% of the weld power, and the best results were found at 50% of preheating. To accurately simulate the physical laser beam absorption and joining optical properties were experimentally measured for the computer FEM simulation. The simulation results showed close correlation between theoretical and experimental results. The developed dual laser process is expected to increase productivity and minimize the cost for the final products.

• Journal of the Korean Solar Energy Society
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• v.27 no.1
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• pp.91-98
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• 2007

Perimeter zone is one of the weakest area in buildings and it makes an increase of heating and cooling loads, in addition to condensation or discomfort with cold-draft to residents in winter. Because of this, it needs to be reinforced by active systems. However, they use fossil fuel, and ultimately greenhouse effect is urged. Thus, we proposed BIPV system functioned as solar collector which can substitute active system. As an fundamental stage, heat balance equation in steady-state by Fortran was used not only, in winter for pre-heating effect and electric power capacity during the day, but also in summer, for the latter during the day and sky radiation effect during the night. Especially, we should have considered shading on PV by IES Suncast, since even a little bit of it makes the efficiency too low for the PV modules to work. As a result, in summer day, the PV panel should be tiled in 70 degrees to gain the most electric power. Moreover, we could verify that this model makes higher temperature and heat flux under 0.02 m/s. On the other hand, the PV had the high efficiency with high velocity because of cooling effect behind the PV. Therefore, we should regard the air current distribution later on.

• Preventive Nutrition and Food Science
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• v.10 no.2
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• pp.191-197
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• 2005

There exist two interesting phenomena in making seafood products from surimi. When salted surimi is kept at a constant low temperature $(4\~40^{\circ}C)$, its rheological properties change from sol to gel, which is called 'setting'. Seafood processors can exploit changes that occur during setting in preparation of surimibased products, because heating at high temperatures, after the pre-heating during the setting process, enhances the gel-strength of salted surimi. Contrarily, when salted surimi or low-temperature set gel is heated at moderate temperatures $(50\~70^{\circ}C)$, a deterioration of gel is observed. The phenomenon is termed 'modori'. In the modori temperature range, heat-stable cysteine proteinases such as cathepsin B, H, Land L-Iike hydrolyze the myosins responsible for gel-formation, resulting in gel weakening modori. This article reviews molecular events occurring during gel setting that improve the quality of surimi-based products, and inhibition of modori by applying proteinase inhibitors. Application of recombinant protein technology to surimi-based products is introduced and its prospects for practical use are discussed.

• Journal of architectural history
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• v.31 no.1
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• pp.19-28
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• 2022

The construction period of the ondol (Korean floor heating system) at Hoeamsa Temple Site is known as Joseon. The main reason is that a large number of remains in the Joseon era were excavated from the ondol floor with an all-around ondol method. This article partially accepts the theory of the creation of Ondol at Hoeamsa Temple Site during the Joseon Dynasty and suggests a new argument that some Ondol remains were built during the Goryeo Dynasty. The grounds for them are as follows. First, through the building sites consistent with the arrangement of the Cheonbosan Hoeamsa Sujogi (天寶山檜巖寺修造記, Record of Repair and Construction of Hoeamsa at Cheonbosan Mountain), it is highly likely that the ondol remains as a basic floor was maintained during the reconstruction period in Goryeo. Second, the all-around ondol method of the Monastery Site has already been widely used since the Goryeo Dynasty. Third, some ondol remains consist of "Mingaejari" and "Dunbeonggaejari," which were the methods of the gaejari (which dug deeper and stayed in the smoke) in the pre-Joseon Dynasty. Based on the above evidence, this study argues that the building sites such as Dongbangjangji, Seobangjangji, Ipsilyoji, Sijaeyoji, Susewaryoji, Seogiyoji, Seoseungdangji, Jijangryoji, and Hyanghwaryoji were constructed during the late Goryeo Dynasty.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.5
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• pp.58-66
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• 2012

The IR signature and radiative base heating from an aircraft plume have been important factors for aircraft survivability in modern battle fields. In order to enhance the aircraft survivability and reduce the base heating, infrared signatures emitted from an aircraft exhaust plume should be determined. In this work, therefore, IR signatures and radiative base heating characteristics are examined in the plume exhausted from the aircraft with operating at altitude of 5 km in M=0.9 and 1.6, respectively. As a result, it is found that the particular wavelength IR signature has high spectral characteristics because of $H_2O$ and $CO_2$ gases in the plume, and the radiative heat flux coming into the base plane increases with higher Mach number and shorter distance.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.11a
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• pp.43-49
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• 2002

A7003 alloy has characteristics of their excellent weldability, high corrosion resistance and superior plastic working however the broadening of application for the alloy has been hampered by the lower extrudability associated by Mg content. For improvement of extrudability and enhanced recovery efficiency during Al scrap recyeling, it has been generally practiced to reduce Mg content in A7003 alloy. Therefore, it is necessary to investigate the influence of Mg content on mechanical strength and extrudability of A7003 alloy. For efficient material processing which has small amounts, life cycle assessment in material processing(MLCA) is evaluated. The quantitative analysis of energy requirements and $CO_2$ emission for production of A7003 extruded bar are estimated with different Mg content and billet pre-heating process (heating source by light oil or LPG). In particular, the estimation of energy requirements was performed within shipping and gating range (except the mining and extraction stages)to investigate the influence of the variables on energy requirements and $CO_2$ emission in detail. As Mg content increased, the flow stress and the extrusion pressure for A7003 alloy increased. It has been thought that an increment in extrusion pressure with increasing Mg content is caused by the solid solution hardening of Mg atoms in the matrix and increment in volume fraction of intermetallic compound, $Mg_2Si$. The extrudability and the tensile strength are equal to, or above that of conventional A 7003 alloy even the content of Mg varied from $1.1wt.\%\;to\;0.5wt.\%$ alloy. This means that minimizing the content of Mg in A7003 alloy can enhance recovery efficiency during Al scrap recycling. It can be quoted that rather than Mg content energy source for billet heating is a prime factor to determine the atmospheric $CO_2$ emission.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.282-289
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• 2012

The IR Signature and radiative base heating from an aircraft plume have been important factors for aircraft survivability in modern battle fields. In order to enhance the aircraft survivability and reduce the base heating, infrared signatures emitted from an aircraft exhaust plume should be determined. In this work, therefore, IR signatures and radiative base heating characteristics are examined in the plume exhausted from the aircraft with operating at altitude of 5km in M=0.9 and 1.6, respectively. As a result, it is found that the particular wavelength IR signature has high spectral characteristics because of $H_2O$ and $CO_2$ gases in the plume, and the radiative heat flux coming into the base plane increases with higher Mach number and shorter distance.

• Korean Journal of Materials Research
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• v.2 no.4
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• pp.257-262
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• 1992

The cure kinetics of a diglycidyl ether of bisphenol A (DGEBA) with 4, 4'-methylene dianiline (MDA) added succinonitrile was studied through the dynamic run method by applying the data to the Kissinger equation which analyses the effect of the heating rate on the temperature at maximum reaction rate using Differential Scanning Calorimetry (DSC) analyzer in the range of 3$0^{\circ}C$-35$0^{\circ}C$. In the DGEBA/MDA system with SN, the activation energy ($E_a$) and the pre-exponential factor (A) were calculated. From these results, the rate constants (k) were obtained according to the different SN contents.

• Journal of the Korean Home Economics Association
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• v.41 no.2
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• pp.107-121
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• 2003

This study was discussed the dyeing of wool and nylon fabrics with Chinese Scholar Tree extract. The extracts of Chinese Scholar Tree was prepared in the condition of heating at $95{\pm}5C$, for 1 hour and cooling to 40C. And then the extracts of color matter treate with vacuum concentration at $60{\pm}2^{\circ}C$, 30mmHg and dried with spray dryer. The dyeing of wool and nylon fabric in this experiment was also employed the mordant dyeing method such as pre-mordant, post-mordant and simultaneous mordant method. The mordanting agents used in this study were as followings ; aluminium potassium sulfate, copper(II) acetate monohydrate, chromium potassium sulfate$.$$7H_2O$, Tin(II) chloride dihydrate, iron(II)sulfate $7H_2O$. For an evaluation of the dyeing property of the mordanting agents, the pre-mordant method, the repeat dyeing and the fastness of the light, dry cleaning, washing and rubbing measured respectively. From the results of the dye absorption, the optimum dyeing condition of the wool and nylon fabrics with Chinese Scholar Tree extract is at 80C dyeing temperature for 60 minutes. The optimum concentration of mordanting agent is Al, Cr, Sn 1%, Fe, Cu 2% solution. In general, the fastness property of the dyed wool and nylon fabrics had a comparatively high grade.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.1
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• pp.8-13
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• 1990

The microscopic relaxation parameters for the single crystal were measured by using thermally stimulated depolarization (TSD). Initial rise method, various heating rate method and total glow peak method were used for the determination of the activation energy and Debye relaxation time from TSD glow curves. Activation energy, pre-exponential factor and relaxation time for impurity-vacancy dipole reorientation were 0.55eV, 1.97$\times$10 super(-12) sec and 12.19sec in average, respectively. Dielectric dissipation factor for the crystal was calculated from the measured TSD glow curve, its value being about 3$\times$10 super(-2).