• Journal of the Korean Vacuum Society
• /
• v.22 no.2
• /
• pp.66-78
• /
• 2013

In order to develop of 80 kW RF plasma torch system, we achieved three-dimensional simulations for the extraction of more information as temperature in torch and fluid behavior analysis, etc. The position of powder injection tube, the plasma discharge characteristics with various input current and various length of ceramic tube, and the plasma temperature characteristics with process gas flow rate such those was simulated. RF thermal plasma torch designed by simulation was manufactured that was measured to the maximum of 89.3 kW power. The mass production using developed 80 kW RF thermal plasma torch system were investigated by characteristics manufactured of Si nano powder. The mass-production level of Si nano-powder was average of 539 g/hr and high yield rate of 71.6%, respectively. The particle size distribution $D_{99}/D_{50}$ of manufacturing nano-powder was investigated to 1.98 as a good uniform.

• Journal of Food Hygiene and Safety
• /
• v.32 no.5
• /
• pp.389-395
• /
• 2017

A simultaneous determination of 5 phenolic acids (gallic acid, chlorogenic acid, caffeic acid, pcoumaric acid, trans ferulic acid) and 9 flavonoids (procyanidin b1, aspalathin, rutin, vitexin, hyperoside, isoquercitrin, luteolin, quercetin, chrysoeriol) in rooibos tea has been carried out by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). A validated analysis method in this study was applied to rooibos aqueous infusions. Rooibos tea is an antioxidant-rich tea which has anti-cancer, anti-aging, anti-inflammatory, anti-diabetic effect. Extraction yield of phenolics depends on steeping time and temperature of water. Tea infusions were prepared by placing 1 g of tea leaves or 1 tea bag in 100 mL of boiled water, and then at 3, 6 and 30 minutes intervals the infused teas were taken to carry out the analysis of phenolic contents. Another tea infusion was conducted with cold water ($25-30^{\circ}C$) for 30 minuntes. As a result, the total amount of phenolics was highest in rooibos tea steeped with hot water for 30 minutes, followed by 6 minutes, 3 minutes and cold water 30minutes and the result has statistical significance.

• Applied Chemistry for Engineering
• /
• v.5 no.4
• /
• pp.588-596
• /
• 1994

A decomposition reaction of bauxite ore with $(NH_4)_2SO_4$ was investigated to prepare Al component pregnant solution for the direct product of high purity $Al_2O_3$ from low grade bauxite ore. Al component in the bauxite was sulfatized to $NH_4Al(SO_4)_2$ or $Al_2(SO_4)_3$ in this decomposition. The optimum conditions of the decomposition for bauxite ore were reaction temperature of $425^{\circ}C$, reaction time of 40min, $(NH_4)_2SO_4$ weight ratio to bauxite of 7.0 and particle size of bauxite ore of -200mesh. The optimum leaching conditions of sulfated bauxite ore were leaching temperature of $100^{\circ}C$, leaching time of 1hr and pulp density of 200ml $H_2O$ to sulfated ore of 1.0g bauxite. Under the above mentioned decomposition and leaching conditions, 94% of Al component in the bauxite ore was extracted.

• Journal of the Korean Society of Food Culture
• /
• v.9 no.1
• /
• pp.71-77
• /
• 1994

This study was undertaken to investigate the physicochemical properties of chitosans produced from chitins which were prepared from shrimp shell under the 4 different conditions(HCl concentration : 1 N, 4 N and reaction temperature $0^{\circ}C,\;20^{\circ}C$). The effects of chitosan on the properties of Kakdugi during storage also were examined. Viscosity of chitosan was markedly different$(313.1{\sim}98.8\;cps)$ depending on the production conditon. Chitosan solution showed pseudoplastic property. The infrared(IR) spectrums of chitosans prepared under the conditions of this study were very simillar, and the degree of deacetylation of chitosan was relatively high$(92{\sim}96%)$ independent of the extraction conditions of chitin. As the storage period was extended, markedly lower pH and higher titratable acidity were resulted in all the groups. Throughout the storage period, pH and titratable acidity of kakdugies with chitosan were higher and lower, respectively than those of control. Viscosity of kakdugi juice was significantly different among the groups and as the storage period increased, the juice viscosity decreased. At the eighth day of storage, the juice of control group was more viscous than those of kakdugies containing chitosan. Throughout the storage period the numbers of total microorganisms and of microorgarnisms of Leuconostoc genus in control kakdugi tended to be higher and lower, respectively than those in kakdugies containing chitosan. The growth of Lac. plantarum was slightly lower in kakdugi containing chitosan C produced at low HCl concentration and high temperature compared to the others.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.6C
• /
• pp.349-354
• /
• 2011

Passive millimeter wave imaging has the capability of detecting concealed objects under clothing. Also, passive millimeter imaging can obtain interpretable images under low visibility conditions like rain, fog, smoke, and dust. However, the image quality is often degraded due to low spatial resolution, low signal level, and low temperature resolution. This paper addresses image registration and fusion between passive millimeter images and visual images. The goal of this study is to combine and visualize two different types of information together: human subject's identity and concealed objects. The image registration process is composed of body boundary detection and an affine transform maximizing cross-correlation coefficients of two edge images. The image fusion process comprises three stages: discrete wavelet transform for image decomposition, a fusion rule for merging the coefficients, and the inverse transform for image synthesis. In the experiments, various types of metallic and non-metallic objects such as a knife, gel or liquid type beauty aids and a phone are detected by passive millimeter wave imaging. The registration and fusion process can visualize the meaningful information from two different types of sensors.

• Clean Technology
• /
• v.26 no.2
• /
• pp.91-95
• /
• 2020

A new eco-friendly synthetic method for N-hydroxysuccinimide (NHS), widely used in the pharmaceutical and fine chemical industries, is developed. Conventional synthesis method yields NHS of about 70% after its reaction with NH₂OH to succinic acid. In this method, NHS can be obtained using low-cost succinic acid, but a great deal of solvents are required as an extraction method to purify NHS, while the work-up process is complicated, resulting in low yield. In addition, there is a safety risk due to the high reaction temperature for commercial production, and it is not economical due to the high cost of production from the generation of much waste because of an acid catalyst and the use of various solvents. In order to make up for this shortcoming, this study used succinic anhydride as a raw material under low temperature reaction and developed a new eco-friendly industrial synthesis method using isobutyl alcohol for a single solvent and non-catalytic reaction. The economic evaluation confirms that there is a cost reduction effect of about 20%. In the future, based on this result, studies may establish a commercial production technology through scale-up research and proceed with foreign technology transfer.

• Korean Journal of Food Science and Technology
• /
• v.27 no.4
• /
• pp.576-581
• /
• 1995

To obtain the basic information for the effective use of collagen, the flow behavior of collagen extracted from skin tissue was studied. The viscosity of collagen varied with sex, age and the kinds of collagen by extraction method. Regardless of the kinds of collagen, the viscosity of collagen extracted from $6{\sim}12$ week old rat was relatively high. In case of the same age, the viscosity showed higher in female than in male rat and in acid soluble collagen than in insoluble collagen. The solution of the collagen showed the characteristics of Bingham plastic and thixotropic fluid, and the viscosity varied distinctly with temperature, pH, ethanol concentration and collagen concentration. As collagen concentration increased to 6%, the consistency of acid soluble- and insoluble collagen showed a tendency to increase linearly(r = 0.972 for acid soluble collagen, r = 0.957 for insoluble collagen). In that range of collagen concentration, the increasing velocity of consistency was higher in acid soluble collagen than in insoluble collagen. The consistency of collagen solution was decreased according to temperature rising. In case of acid soluble collagen, the consistency is decreased abruptly between $30{\sim}40^{\circ}C$. According to pH variation, the consistency of acid soluble collagen showed biphasic phenomenon, though the consistency of insoluble collagen was found not to be influenced by pH. The consistency of acid soluble- and insoluble collagen according to ethanol concentration showed high between $40{\sim}60%$ of ethanol concentration.

• Journal of Korean Society of Environmental Engineers
• /
• v.33 no.1
• /
• pp.54-59
• /
• 2011

This test established the bioavailability and sample input by mixing the maintaining the microbial machine parts and food waste leachates in weight of 2:1 as advanced experiment, maintaining the constant temperature, agitating and observing its weight and property change for 60 hours. And, I injected daily the established microbial machine parts and food waste leachates rate, maintained the temperature in the reactor with $55{\sim}65^{\circ}C$, and agitated with constant speed. I studied the recycling possibility of food waste leachates by extracting the sample after 24 hours, verifying its characteristics, and repeating the food waste leachates input and sample extraction for about 40 days. Considering all about the results of this study, I saw that 87.32% of food waste leachates was reduced, and the solid of bluebug or food included in the food waste leachates was decomposed within 24 hrs. pH for 43 days after 9 days of stabilization period was maintained from 3.7~3.9 and the ignition loss from 88.67~87.3%, and the quantity of organic matter from 77.6~80.88%. With the similar result daily maintained, it is considered to progress more the minimization by inputting the future food waste leachates. C/N rate satisfies the less than 25 that is the composting basis within 8 days, maintaining between 13~15, with 2% of salt not exceeded, it is able to recycle as the compost of food waste leachates as based on the composting with no extracted heavy metal content.

• Korean Journal of Food Science and Technology
• /
• v.34 no.3
• /
• pp.437-443
• /
• 2002

Using agar and gelatin as wall materials, onion oil was microencapsulated using the extrusion spraying technology. A sensitive methodology was developed for quantitative determination of the microencapsulation yield through ethyl acetate extraction and gas chromatographic analyses. Optimal conditions for the microencapsulation process consisting of the ratio of [core material, Cm] to [wall material, Wm] ($X_1$), temperature of dispersion fluid ($X_2$), detergent concentration in dispersion fluid ($X_3$), and concentration of emulsifier $(X_4)$ were determined using response surface methodology. The regression model equation for the yield of microencapsulation (Y, %) of onion oil could be predicted as $Y\;=\;97.028571-0.775000\;(X_1)-0.746726\;(X_1){\cdot}(X_1)\;-\;1.100000\;(X_3){\cdot}(X_2)$. The optimal conditions for the microencapsulation of the onion oil were determined as the ratio of [core material] to [wall material] of 4.5 : 5.5 (w/w), the temperature of dispersion fluid of $17.1^{\circ}C$ detergent concentration in dispersion fluid of 0.03%, and the concentration of emulsifier of 0.42%. Results revealed the most stable microcapsule of onion oil could be formed with the highest yield of microencapsulation (more than 95%) under optimal conditions.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.29 no.2
• /
• pp.63-72
• /
• 2011

The aim of this study, a traditional residential area in the environmentally friendly design techniques to identify the techniques and principles that have been carried out to reestablish the principles. To do this, through literature review environmental performance is reflected in the traditional residential area side of resources conservation, locational aspects, spatial configuration, and how cases were selected looking for ways to apply modern. Are examples of upper class housing in the Chosen Dynasty Period period construction relatively well-preserved round and a good building with a clear housing Dokrakdang year were selected. Locational aspects of the terrain with minimal changes to the building and construction techniques were entirely in terms of environmental conservation and environmental temperature was adjusted to regulate the room temperature technique could be seen. In terms of cycling in natural materials were recycled. and water make used of positive through water cycling technique & water control. In addition, the importance of landscape views overlooking the landscape from inside to outside through the regulation of the various internal and external space technique was used to attract and expand. Traditionality in the pursuit of modern space, simply cut off because of tradition rather than to restore or recover the organizing principle inherent in the traditional space, and extraction of the contemporary social, cultural and environmental understanding of space is acceptable in basis. Environmentally-friendly design techniques in a traditional residential area for a long time to be developed by the experience of its application of modern environmental and energy problems and pleasant environment to the creation of human life and are subject to significant swings in that.