• Textile Coloration and Finishing
• /
• v.6 no.1
• /
• pp.19-27
• /
• 1994

Mimosa and Quebracho are, in general, tanned with leather skin, finished silk fabrics according to temperature, treatment time, tannin concetration, pH, and studies that relation between tannin weighting and various factors. This makes fundamental study on characteristic of tannin treated fabrics. and the results are as fallows : 1. λ$_{max}$ was found at 278.5nm for Mimosa. 279.5nm for Quebracho. Also a stability was good in standing time and heating. 2. The higher tannin treatment temprature was, the better tannin weighting effect was. But they were slightly decreased at over 8$0^{\circ}C$, and K/S was slowly increased. 3. As tannin treatment time increased, tannin weighting effect increased but they were decreased at over 8$0^{\circ}C$, 90min. 4. As tannin concentration increased, tannin weighting was increased. 5. In tannin weighting effect according to various pH conditions, the it's best range of pH were 3.5~5.5 of Mimosa, 2.5~3.5 of Quebracho.o.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.23 no.4
• /
• pp.349-355
• /
• 2021

The effect of night temperature was investigated on mango (Mangifera indica cv. Irwin) for setting appropriate night temperature and managing mango cultivation in a greenhouse. Different night temperatures (10, 15, and 20℃) were treated from budding to fruit development in mango trees. As night temperature increased, the initiation of flowering, full blooming, fruiting, and fruit development tended to be accelerated. There were no significant differences in the growth of shoots flushed after the fruit harvest among trees treated with different night temperatures. The lengths of the flower stalk were the shortest at 10℃ of night temperature; however, there were no significant differences between 15℃ and 20℃ of the night temperature. The length, diameter, and weight of mango fruits were higher at 15℃ and 20℃ than 10℃. Soluble solid contents and acidities showed no difference; the firmness and skin color were better as the night temperature increased. Accordingly, setting the minimum night temperatures to 15℃ or 20℃ can increase the number of fruits and produce high-quality fruits when cultivating mango in the greenhouse. Even the minimum night temperature to 15℃ can reduce heating costs in the greenhouse.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.27 no.2
• /
• pp.65-69
• /
• 2017

AlN single crystal was thermally treated at 1600, 1700 and $1800^{\circ}C$ in the ambient pressure of under 100 torr. AlN single crystal was obtained by PVT (Physial Vapor Transport) method using by a facility having a growth part which was heated by RF (Radio Frequency) induction heating. The single crystal specimens surface was evaluated by optical microscope and it was recognized that their morphology was varied with the heat treatment temperature and a set ambient pressure. In this report, the optical microscopic results were reported. According to the increase of temperature the crystal surface was etched thermally. It was evaluated by appearance of small pits on the crystal surface.

• Proceedings of the IEEK Conference
• /
• 2001.10a
• /
• pp.571-575
• /
• 2001

To examine the grinding effect through preheating of waste concrete as a way of retrieving coarse aggregates from waste concrete, the removal rates of cement mortar and paste of both recycled aggregates and heated and grinded ones were investigated. As the preheating temperature increased, the removal rate of cement mortar from waste concrete was raised, and this kind of removal hardly affected the abrasion rate and specific gravity of aggregates. On the other hand, when it was treated over 40$0^{\circ}C$ of preheating temperature, the absorptance was reduced to less than 2.17, and cement mortar was effectively separated from waste concrete. It could meet the Korean Standards on recycled aggregates for concrete, and it is expected to expand the scope of utilization by making it possible to retrieve the aggregates which have the properties close to natural aggregates.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.5
• /
• pp.803-807
• /
• 2008

A making process of DSC(dye sensitized solar cell) was presented. In general, Photo electrodes of DSC was made by using colloid paste of nano $TiO_2$ and processing of Doctor-blade printing and high temperature sintering for porous structure. These methods lead to cracks on $TiO_2$ surface and ununiform of $TiO_2$ thickness. This phenomenon is one factor that makes low efficiency to cells. After $TiO_2$ printing on TCO glass, a physical vibration was adapted for reducing ununiform of $TiO_2$ thickness. And a thermal treatment at low temperature(under $75^{\circ}C$) was adapted for reducing cracks on $TiO_2$ surface. In this paper, we have designed and manufactured an ultrasonic circuit (100W, frequency and duty variable) and a thermal equipment. Then, we have optimized forcing time, frequency and duty of ultrasonic irradiation and thermal heating for surface treatment of photo-electrode of DSC. In I-V characteristic test of DSC, ultrasonic and thermal treated DSC shows 19% improved its efficiency against monolithic DSC. And it shows stability of light-harvesting from drastically change of light irradiation test.

• Textile Coloration and Finishing
• /
• v.7 no.2
• /
• pp.24-31
• /
• 1995

The properties of carbon fibers made from PAN are controlled by the heat treatment conditions. The length changes of high strength homo-PAN and co-PAN (acrylonitrile/acrylamide= 98/2wt% ) fibers under constant tensile stress during heat treatment in nitrogen gas were investigated by measuring the shrinkage behavior. In order to elucidate the relation between the length and fine structure change, the measurements of the crystalline orientation and birefringence index etc. were made for the fibers treated under linear heating up to 27$0^{\circ}C$. There are two regions in the length change with heat treatment temperature. The change in the initial period is mainaly due to the relaxation of amorphous molecular chain confined by the fiber-manufacture process. The length change in later period is considered to arise as cyclization reactions. The co-PAN fibers caused a larger shrinkage, while the onset of the shrinkage change in later period is, shifted to lower temperature. Significant morphological changes are shown to precede onset of the cyclization reactions and also during these reactions.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.11a
• /
• pp.603-608
• /
• 2004

The paper analyzes a scheme of decontamination of radionuclides from concrete structures, in which rapid microwave heating is used to spall off a thin contaminated surface layer. The analysis is split in two parts: (1) The hygrothermal part of the problem, which consists in calculating the evolution of the temperature and pore pressure fields, and (2) the fracturing part, which consists in predicting the stresses, deformations and fracturing. The rate of the distributed source of heat due to microwaves in concrete is calculated on the basis of the standing wave normally incident to the concrete wall with averaging over both the time period and the wavelength because of the very short time period of microwaves compared to the period of temperature waves and the heterogeneity of concrete. The reinforcing bars parallel to the surface arc treated as a smeared steel layer. The microplane model M4 is used as the constitutive model for nonlinear deformation and distributed fracturing of concrete. The aim of this study is to determine the required microwave power and predict whether and when the contaminated surface layer of concrete spalls off. The effects of wall thickness, reinforcing bars, microwave frequencies and power are studied numerically. As a byproduct of this analysis, the mechanism of spalling of rapidly heated concrete is clarified.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.28 no.4
• /
• pp.392-396
• /
• 1995

Chitosan was prepared from red snow crab (Chinonecetes japonicus) under various conditions of deacetylation (NaOH concentration, heating temperature, heating time and intermittent and repetition treatment). By measuring the degree of deacetylation and the molecular weight (Mw), effect of preparation condition was studied. As the concentration of NaOH increased in deacetylation process, for chitosan treated over $40\%$ NaOH, the rate of increase of the deacetylation of chitosan decreased, but the difference of Mw decrease was nearly constant. When treatment temperature increased from $130^{\circ}C$ to $150^{\circ}C$, the deacetylation degree increased only $3^{\circ}C\;from\;84\%\;to\;87\%,$ but Mw decreased from 267,000 to 85,800. The difference of Mw decrease of chitosan treated $130-150^{\circ}C$ was larger than that with $90-130^{\circ}C$. The deacetylation degree and Mw of the chitosan prepared by continuous treatment for 3 hrs was$84\%$ and 267,000. On the other hand those of chitosan with intermittent and repetition treatment for 3hrs was $93\%$ and 28,000. In order to increase the degree of deacetylation and inhibit depolymerizing, the intermittent and repetition treatment was found to be more effective than the continuous treatment.

• Polymer(Korea)
• /
• v.29 no.1
• /
• pp.64-68
• /
• 2005

To recycle collected high-impact polystyrene (HIPS) wastes as liquid fuel, depolymerization characteristics of HIPS by pyrolysis was studied. The effects of temperature and time on the pyrolysis of HIPS were investigated. The depolymerization temperature and activation energy of HIPS pyrolysis increased with increasing heating rate. In general, conversion and liquid yield gradually increased with pyrolysis temperature and pyrolysis time. Each liquid product formed during pyrolysis was classified into gasoline, kerosene, light oil and heavy oil according to the distillation temperature based on the petroleum product quality standard of Korea Petroleum Quality Inspection Institute. As a result, the amount of liquid products produced during HIPS pyrolysis was in the order of gasoline》heavy oil〉kerosene〉light oil. Especially 51${\pm}$6 wt% of HIPS treated was obtained as gasoline.

• Applied Chemistry for Engineering
• /
• v.18 no.3
• /
• pp.245-250
• /
• 2007

Adsorption characteristics of 1,2-dichlorobenzene on the surface of heat treated silica gel were determined by the moment analysis. The heat treatment of the silica gel was performed at temperatures of 150, 500, and $800^{\circ}C$ and pulse-response of 1,2-dichlorobenzene was measured in a gas chromatograph equipped with thermal conductivity detector (TCD) using the packed column. Equilibrium adsorption constants and isosteric heat of adsorption were recorded the highest value at $500^{\circ}C$. This might be due to the increase of interaction between silica surface and 1,2-dichlorobenzene as the decrease of OH concentration and moisture by increase of heating temperature. Axial dispersion coefficient calculated by the moment method was about $0.046{\times}10^{-4}{\sim}1.033{\times}10^{-4}m^2/sec$ and pore diffusivity of heat treated silica gel at $500^{\circ}C$ measured the lowest value. Because heat treating at $800^{\circ}C$ caused the specific surface area to reduce, equilibrium adsorption constants and isosteric heat of adsorption were decreased.