• Journal of the Microelectronics and Packaging Society
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• v.23 no.1
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• pp.35-39
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• 2016

The flexible and superhydrophobic properties of silica aerogels are extremely important material for thermal insulation and oil spill cleanup applications for their long-term use. Flexible silica aerogels were synthesized by using a two-step sol-gel process with precursors, methyltrimethoxysilane (MTMS) followed by supercritical drying. Silica aerogels were prepared at different molar ratio of methanol to MTMS (M). It was observed that the silica aerogels prepared at M=28 were monolithic but inelastic in nature, however, for M=35, the obtained aerogels were monolithic, elastic in nature with less shrinkage. The microstructural studies were carried out using scanning electron microscopy and surface area measurements. The hydrophobicity was confirmed by Fourier transform Infrared spectroscopy and water contact angle measurements. The detailed insight mechanism for flexible nature of silica aerogels and hydrophobic behavior were studied.

• Journal of the Korean Society of Costume
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• v.58 no.8
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• pp.63-73
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• 2008

From the ancient Korea to the late Joseon Korean fur and leather had been preferred in and out of Korea for their good quality and excellent manufacturing skill. Since Unified Silla (A.D.676${\sim}$A.D.936) Korean fur and leather were manufactured divisionally by workmen specialized in materials and products, and such manufacturing process was succeeded to Goryeo and Joseon. Manufacturing of fur and leather was consisted of as follows: hunting and butchering - peeling - beating with a paddle and removing fat - oil manufacturing - drying - tanning, then cutting and sewing, and there was a special caring method. In order to make good fur and leather, each process of manufacturing needed particular techniques and all available methods were tried to have tender fur and leather by using smoking, excrement, lime, vegetable tannin and even cerebral liquid. And also required mouth-chewing and hand-pounding with a lot of time and of labor Keeping furs resilience and flexibility, sowing several skins together, even when the after-all-process skin was converted into clothes, was much more difficult than sewing fabric. Thus, the manufacturing cost was as much expensive as skin materials, and the volume of manufacturing of fur and leather was also limited. Therefore, fur and leather must have been popular for scarcity value in the manufacturing process, and this scarcity must have caused an extreme luxury of fur.

• The Korean Journal of Nuclear Medicine
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• v.23 no.1
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• pp.63-69
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• 1989

In order to develop technetium-99m-labelled human albumin microsphere (HAM) for lung scintigraphy, various experimemts such as preparation and fractionation of HAM, establishment of optimal labelling conditions, determination of radiochemical purity, stability test and biodistribution of $^{99m}Tc-HAM$ were carried out. HAM was prepared from the suspension of 1ml aqueous human serum albumin (25%) in 130 ml of olive oil at $130\sim135^{\circ}$ with vigorous stirring. The resulting HAM was fractionated with microsieve to get the desired particle size $(15\sim50\mu)$ and autoclaved for sterilizaiton. The HAM particles were treated with stannous chloride and the pH of the suspension was adjusted to $3.0\sim3.5$ with phosphate buffer. After freeze-drying the contents of single reaction vial containing 5 mg of HAM and 0.2 mg of $SnCl_2$ it was reacted with $Na^{99m}TcO_4$. The labelling yield was higher than 99.5% and the stability of $^{99m}Tc-HAM$ was high enough to maintain 99.1% of radiochemical purity up to 24 hours. Lung and liver uptake in mice was found to be 94% and 0.9%, respectively. Excellent rabbit and human lung scans were also obtained.

• Korean Journal of Pharmacognosy
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• v.47 no.4
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• pp.389-398
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• 2016

Korea, China and Japan have developed individually their own official compendia for crude drugs to tune with the times. Recent globalization has enlarged trade volume among these countries, and so the necessity for new quality standards has increased. This study was accomplished to offer basic data and appropriate suggestions to rebuilding standard principles for quality control of crude drugs in Korean official compendia. For this, seven standard items related to quality control in official compendia of these countries were compared. The items were identification, loss on drying, total ash, acid-insoluble ash, extract content, essential oil content and assay. The official compendia of three countries were the Korean Pharmacopoeia Eleventh Edition, the Korean Herbal Pharmacopoeia 2015, Chinese Pharmacopoeia 2015 and Japanese Pharmacopoeia Seventeenth Edition. Based on this basic research, new principles for each standard of crude drugs were suggested.

• Korean Journal of Oriental Medicine
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• v.12 no.3 s.18
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• pp.79-90
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• 2006

This study was investigated to determine the quality monitoring of distributed materials from Glycyrrhizae Radix (26 samples), Atractylodis Rhizoma Alba (24 samples) according to storage period after $1{\sim}3$ year. We have estimated by identification, purity, loss on drying, ash, acid insoluble ash, extract content, essential oil content, assay and microbial contamination. As a result, Glycyrrhizae Radix (26 samples) were satisfied with the standard of K.P. (Korean Pharmacopoeia) and WHO's microbial contamination limit standard. In the Atractylodis Rhizoma Alba (24 samples), 2 samples were not satisfied with the standard of K.P.(Korean Pharmacopoeia) and WHO's microbial contamination limit standard. The results make practical application of the basic data for the quality control of herbal medicine in storage.

• Magazine of the Korean Society of Agricultural Engineers
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• v.21 no.1
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• pp.78-85
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• 1979

In order to obtain the basic data for designing optimum flat plate solar air heaters, which can be operated with relatively low temperature for drying farm products, 8 different treatment of solar air heaters were devised and tested for their heating performances and efficiencies. The results were analised and summarized as follows. 1. The primary factors, structure of air path (C), black coating materials (A) and bottom coating methods (B) showed very high significant effect of far above 1% level. With respect to the mutual multiplying effect of secondary factors, 1% level of significance was found with coating materials and methods (AB), and 5% level of significance was found with coating materials and air path structure (AC). 2. The heating performance of the air heaters with winding air path showed about twice those with straight air path. 3. The Korean black ink which is less expensive than dim oil paint showed 3-4% better heating efficiencies as the black coating material of flat plate solar air heaters. 4. The heating efficiencies of the solar air heaters whose bottoms were not black coated were 2-3% higher than those with black coated bottoms. 5. The highest heating efficiency of solar air heater among 8 different treatment was found in the plot of Korean black ink-bottom not coated-winding air path showing 29.0-34.5%

• Korean journal of food and cookery science
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• v.9 no.3
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• pp.215-221
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• 1993

Bioactivity of the extract from various processed garlic was evaluated based on the inhibition of lipoxygenase(LPO), and the effect of some stabilizers on the bioactivity was investigated. Water, ethanol or chloroform extract of 30 min boiled garlic showed 75%, 76% or 70% inhibition, respectively, compared to extracts of fresh garlic. In pickled garlic, LPO inhibition decreased gradually during storage. Chloroform extract of 40 day-stored pickled garlic inhibited LPO by 77%, and even on 60th day storage it still retained inhibitory effect of 73%, compared to that of fresh garlic. Meanwhile, the powdered (freeze-dried) garlic showed more bioactivity(80%) than the other processed garlics, and moreover, the jrreversible/unstable components seem to be stabilized by freeze-drying. The optimum pH for stabilization of bioactive components in garlic macerate was pH 3 for 48 hr incubation and pH 11 for 6 hr incubation. In addition, the effect of NaCl was not so great, although but maximal stabilization was observed at 150 mM. Stabilizing effect of $\alpha$-tocopherol was markedly great, and at 6mM it showed 308% stabilizing effect after 48hr incubation. More stabilizing effect was observed at lower concentrations of ascorbic acid($\leq$0.6mM) than higher concentrations. The stabilizing effect of soybean oil was found to be remarkable only during initial period(6 hr) of incubation.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.5
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• pp.687-694
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• 1999

This study was conducted to develop new drying process for automatic control and marine engi-neering system. Air-water tests were carried out to investigate dryer performance. The dispersed flow in he dryer test apparatuses was also simulated by using a numerical code which solves the Dittus-Boelter equation for continuous liquid phase and the Reynolds equation of droplet motion for continuous liquid phase and the Reynolds equation of droplet motion for dispersed phase to predict droplet removal efficiency. Proper conditions for dehumidification were optimized by response ambient conditions. When the selected indexes were constrained in the range of 85-98% moisture content above $15^{\circ}$ and more than mass flow rates of moist air 750kg/h. The numerical results were compared with the experimental data pertaining to the removal effi-ciency at chamber stage and overall pressure drop along concentric tubes Good agreement was obtained as for the efficiency while relatively poor agreement was obtained for the relative humidity. The results also showed that the efficiency depended strongly on the relative humidity at the inlet condition which indicated the importance of estimating the heat exchanger length. Effects of some design parameters in both removal efficiency and breakthrough onset condition are discussed.

• Carbon letters
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• v.21
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• pp.81-85
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• 2017

The objective of this study is the removal of chromium from tannery wastewater by electrosorption on carbon prepared from lignocellulosic natural residue "peach stones' thermally treated. The followed steps for obtaining coal in chronological order were: cleaning, drying, crushing and finally its carbonization at $900^{\circ}C$. The characterization of the carbon material resulted in properties comparable to those of many coals industrially manufactured. The study of the dynamic adsorption of chromium on the obtained material resulted in a low removal rate (33.7%) without applied potential. The application of negative potentials of -0.7 V and -1.4 increases the adsorption of chromium up to 90% and 96% respectively. Whereas a positive potential of +1.4V allows desorption of the contaminant of 138%.

• Korean Journal of Materials Research
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• v.1 no.2
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• pp.71-76
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• 1991

The superconducting powders in $YBa_2Cu_3O_{7-x}$ and Bi-Pb-Sr-Ca-Cu-O system were easily prepared from water in oil type emulsion by loading each cation into the aqueous phase. In $YBa_2Cu_3O_{7-x}$ system, the superconducting orthorhombic phase was formed by calcining at $750^{\circ}C$ for 10h in $O_2$. The size of the superconducting phase powders was submicron. The density of the sintered specimen using this powders was about 95% of the theoretical density and the resistance sharply decreases at about 90K, In Bi-Pb-Sr-Ca-Cu-O system the low Tc phase($(Bi, Pb)_2Sr_2Ca_1Cu_2O_y$) was formed by calcining at $800^{\circ}C$ for 10h in a low oxygen partial pressure of 1/20 atm The shape of clacined powder is thin plate of which size is about $2\mu\textrm{m}$ and thickness is smaller than $\mu\textrm{m}$. It was observed that the high Tc phase ($(Bi, Pb)_2Sr_2Ca_2Cu_3O_y$) was formed by sintering at $850^{\circ}C$ for 30h in oxygen pressure of 1/20 atm without intermediary grinding. The above sintered sample exhibited superconductivity with a Tc(zero)=105K.