• Korean Journal of Materials Research
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• v.13 no.12
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• pp.806-811
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• 2003

Ultrafine TaC powders were synthesised by spray drying using tantalum oxalate solution. The spray dried powders were spherical shape and less than 30 $\mu\textrm{m}$ in size. The powders calcined at 500 and X$700^{\circ}C$ showed amorphous structures and $Ta_2$$O_{5}$ phase was obtained by calcining at $700^{\circ}C$. The particle size and shape remains constant after calcination. The calcined spherical powders were composed of an agglomerate of primary particles under 50 nm in size. The complete formation of TaC could be achieved by heat treatment at $1050^{\circ}C$ for 6 hrs. The observed size of TaC powders by TEM was less than 200 nm.

• Korean Journal of Food Science and Technology
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• v.34 no.1
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• pp.37-42
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• 2002

This study was performed to provide basic that will predict the usefulness of Gastrodiae Rhizoma as food materials. The physicochemical properties of raw, freeze-dried, and hot air-dried Gastrodiae Rhizoma were investigated and analyzed. The moisture content of raw Gaxtrodiae Rhizoma was 81.20%. The moisture, crude protein, crude fat, crude ash and carbohydrates of freeze-dried Gastrodiae Rhizoma were 7.61%, 6.21%, 1.50%, 2.55%, and 89.74%, respectively. The total dietary fiber (TDF) of freeze-dried Gastrodiae Rhizoma was 11.68%. The K (1265.03 mg%) was the highest mineral found in Gastrodiae Rhizoma. Aspartic acid (1272.10 mg%) and glutamic acid (1249.50 mg%) in Gastrodiae Rhizoma were major amino acids. Linoleic acid (53.79%), palmitic acid (20.17%), oleic acid (11.93%), and linolenic acid (4.78%) were principal fatty acids in crude fat of Gaxtrodiae Rhizoma. Most of the free sugars of freeze-dried Gastrodiae Rhizoma was maltose (11.04%). In color, the freeze-dried showed the highest lightness (94.52) and the $60^{\circ}C$ hot air-dried showed the highest redness(0.76) and yellowness (16.41). The color differences among freeze-dried, $40^{\circ}C$ hot air-dried, and $60^{\circ}C$ hot air-dried Gastrodiae Rhizoma were distinguished markedly. Vitamin C contents in raw, freeze-dried, and $60^{\circ}C$ hot air-dried Gastrodiae Rhizoma were 0.015%, 0.010%, and 0.002%, respectively. The organoleptic characteristics of raw, freeze-dried, and hot air-dried Gastrodiae Rhizoma were evaluated and compared on the basis, 5 points of raw Gastrodiae Rhizoma by 9 points scale. The undesirable characteristics, such as fishy odor, sewage odor, bitter taste, bad and salty taste, decreased, while desirable characteristic such as sweet taste was maintained or increased considerably as drying temperature got higher.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.4
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• pp.112-117
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• 2002

This study was conducted to induce the optimal composting conditions of pig manure mixed with sawdust and dried paper-mill sludge in the composting for production of high quality compost. Pig manure contains high water content and How C/N ratio because of comparatively high nitrogen content than sawdust and dried paper-mill sludge. Therefore the addition of dried paper-mill sludge and sawdust to the raw materials helps controlling the C/N and the water content of compost pile. The composting system used in the experiment was agitated static bed system. The physical properties of the mixed raw materials was not good at the working conditions in the early stage of composting. The temperature of compost heap reaches at $60^{\circ}C$within 5 day after starting composting in P-2 treatment mixed with pig manure and sawdust(56.6 : 43.4). Then the water content of P-2 was 58%. The pH in all treatments were slowly decreased as the composting was proceeded. Although the changes of T-C and T-N were not extended because of the short composting experiment period. Reduction rates of T-C in treatments were 5-12% without special difference. By considering the efficiency of composting in each of five treatments with pig manure the optimal water contents was about 57% level. Mixing a sawdust as a bulking agent was more positive than dried paper-mill sludge from a viewpoint of compost quality.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.7
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• pp.991-996
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• 2003

Determination of regional microbial contamination in the process of rice rolled in dried laver (Kimbab) and effects of gamma irradiation on the improvement of hygienic quality and shelf stability were investigated. Total aerobic bacterial distribution of raw materials of Kimbab were; 10$^{6}$ ∼10$^{7}$ CFU/g in dried laver, 10$^3$ CFU/g in cucumber and below 10 CFU/g in steamed rice, ham, fried egg, and salted radish. Total coliform bacteria were 10$^3$ CFU/g in dried laver and detected below detection limit (10 CFU/g) in other raw materials. And it was arithmetically calculated that the levels of total aerobic bacteria and coliform bacteria in Kimbab does not exceed 10$^{5}$ CFU/g and 10$^1$ CFU/g under the aseptic process, respectively. However, microbial contamination levels in just prepared Kimbab in a market were about 10$^{6}$ CFU/g of total aerobic and coliform bacteria. Therefore, it was considered that microbial contamination of Kimbab is mainly originated from environmental uptake during the preparation. The representative media for putrefying bacterial growth were steamed rice. Coliform bacteria were mainly increased in ham and fried egg during storage. The bacteria in dried laver were radio-resistant and survived at 3 kGy of gamma irradiation. Coliform bacteria on EMB agar plate were eliminated at the dose of 2 kGy. The sensory acceptability of 2 kGy irradiated Kimbab was stable and the Kimbab can be preserved for 24 hour at 15$^{\circ}C$. Therefore, it was considered that optimal irradiation dose for radicidation of Kimbab was 2 kGy.

• Journal of Periodontal and Implant Science
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• v.23 no.2
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• pp.315-330
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• 1993

The ultimate goal of periodontal treatment has been to facilitate regeneration of diseased periodontal tissues, destroyed by inflammatory periodontal disease. Various implant materials have been used to restore the alveolar bone defects. Of the various materials, porous replamineform hydroxyapatite (PHA) has good biocompatibility when placed in a bone tissue, and maintains alveolar ridge for a long period. Decalcified freeze dried bone(DFDB) has been widely used in alveolar bone defects because of its conformity and high osteogenic potential. The purpose of this study was to evaluate the effects of PHA and DFDB on the regeneration of the alveolar bone between fresh extraction sockets and periodontally involved extraction sockets. Experimental periodontitis was induced by the ligation of orthodontic elastic threads after surgically creating periodontal defects on the premolars on the right side of 2 adult dogs for 8 weeks. Following the extraction of each tooth, PHA and DFDB were inserted in the extraction sockets. In control group 1, PHA was inserted in the fresh extraction sockets, and in control group 2, DFDB was inserted. In experimental group 1, PHA was inserted in the periodontally involved extraction sockets, and in experimental group 2, DFDB was inserted. After 20 weeks, the specimens were prepared and stained with Hematoxylin-Eosin stain for the light microscopic evaluation. The results of this study were as follows. 1. No inflammation associated with implant materials was evident in any of the groups. 2. DFDB was completely resorbed, PHA was remained in the extraction sockets in the control and experimental groups. 3. In control group 1 and experimental group 1, extraction sockets were not completely filled with new bone. However, original forms of alveolar crests were maintained in control group 2 and experimental group 2. 4. In control group 1 and exprimental group 1, PHA particles surrounded with many giant cells were well tolerated by the fibrous connective tissues in the coronal part of the socket, In the inferior part of the socket, PHA particles were incorporated into the new bone. In both control group 2 and experimental group 2, DFDB was replaced by newly remodeled bone. 5. No differences of degree of new bone formation were evident between control and experimental groups.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.4
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• pp.221-230
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• 2012

Objectives: This study sought to evaluate the efficacy of collagen graft materials, as compared to other graft materials, for use in healing calvarial defects in rabbits. Materials and Methods: Ten mm diameter calvarial defects were made in ten rabbits. The rabbits were then divided into 4 groups: control, autogenous bone graft, SureOss graft, and Teruplug graft. Bone regeneration was evaluated using histological and radiographic methods. Results: Based on visual examination, no distinct healing profile was observed. At 4 weeks after treatment, histological analysis showed there was no bone regeneration in the control group; however, at 8 weeks after treatment, new bone formation was observed around the margin of the defective sites. In the autogenous bone graft group, new bone formation was observed at 4 weeks after treatment and mature bone was detected around the grafted bone after 8 weeks. In the SureOss graft group, at 4 weeks after treatment, acute inflammatory and multinuclear cells were noted around the grafted materials; at 8 weeks after treatment, a decrease in graft materials coupled with new bone formation were observed at the defective sites. In the Teruplug graft group, new bone formation was detected surrounding the bone margin and without signs of inflammation. There were statistically significant differences observed between the graft and control group in terms of bone density as evidenced by radiographic analysis using computed tomography (P<0.05), particularly for the autogenous bone graft group (P<0.001). Conclusion: These results suggested that autogenous bone, SureOss and Teruplug have the ability to induce bone regeneration as compared to an untreated control group. The osteogenic potential of Teruplug was observed to be lower than that of autogenous bone, but similar to that of SureOss.

• Korean Journal of Materials Research
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• v.23 no.4
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• pp.246-249
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• 2013

Nano-sized ${\beta}$-SiC nanoparticles were synthesized combined with a sol-gel process and a carbothermal process. TEOS and carbon black were used as starting materials for the silicon source and carbon source, respectively. $SiO_2$ nanoparticles were synthesized using a sol-gel technique (Stober process) combined with hydrolysis and condensation. The size of the particles could be controlled by manipulating the relative rates of the hydrolysis and condensation reactions of tetraethyl orthosilicate (TEOS) within the micro-emulsion. The average particle size and morphology of synthesized silicon dioxide was about 100nm and spherical, respectively. The average particles size and morphology of the used carbon black powders was about 20nm and spherical, respectively. The molar ratio of silicon dioxide and carbon black was fixed to 1:3 in the preparation of each combination. $SiO_2$ and carbon black powders were mixed in ethanol and ball-milled for 12 h. After mixing, the slurries were dried at $80^{\circ}C$ in an oven. The dried powder mixtures were placed in alumina crucibles and synthesized in a tube furnace at $1400{\sim}1500^{\circ}C$ for 4 h with a heating rate of $10^{\circ}C$/min under flowing Ar gas (160 cc/min) and furnace cooling down to room temperature. SiC nanoparticles were characterized by XRD, TEM, and SAED. The XRD results showed that high purity beta silicon carbide with excellent crystallinity was synthesized. TEM revealed that the powders are spherical shape nanoparticles with diameters ranging from 15 to 30 nm with a narrow distribution.

• Resources Recycling
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• v.25 no.6
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• pp.92-97
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• 2016

Spray dried $Cr_2O_3$ powder having an agglomerated structure of particles was twice treated into a plasma flame to increase its apparent density. The powder subjected to the first densification treatment did not show the entirely melted state keeping inner particle hollows, and it was fully melted after the second processing only. The powder size as a result of the second treatment decreased, and the apparent density as well as flowability were increased due to melting and surface smoothing effects. But a part of particles after the second densified treatment showed the hollow structure, especially those which were above $30{\mu}m$ in size. This densification behavior of the powder has been qualitatively discussed in terms of the thermal conductivity and inner gas pressure within aggregates exposed to the plasma flame.

• Journal of Environmental Science International
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• v.6 no.5
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• pp.531-539
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• 1997

Lead sorption performances by biomass of nonliving, dried marine brown algae Undaria phnaunda, Hlzikia hsyormls. and Sugassum fulvellum used as biosorbent materials were investigated. As the amount of biosorbent materials added was increased, the lead removal by biosorbent materials Increased but the lead biosorption capacities decreased. However, with increasing Initial lead concentration the lead biosorption capacities by the biosorbent materials Increased but lead removal efficiencies decreased. In the range of Initial lead concentration(Co) 10-500 mg/L the lead biosorption capacities and removal efficiencies by the biosorbent materials Increased with increasing pH. Among the biosorbent materials used in this study, the lead biosorption capacities decreased in the following sequence: U. plilnaunda > H. fusiformis > S. fulvellum. The lead biosorption by biosorbent materials were expressed by the Langmuir Isotherm better than the Freundlich Isotherm. The biosorption rate could be expressed by the first order reaction rate equation for initial lead concentration like that rad : 0.288Co for U. phanda, rad = 0.255Co for H. fusiformis, and rad : 0.161Co for S. fulvellum. Key words : Lead, biosorption, biosorbent, Undaria pinnatinda, Hiztkia fusiformis, Sargassum fulvellum, Langmuir isotherm, Freundlich isotherm, biosorption rate.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.521-526
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• 2002

In this paper, we described about the characteristic evaluation of environment-friendly ceramic paint with calcium-silicate mineral as a main binder. Particularly, we performed discharge of the environmental poisoning materials(e.g. VOCs, heavy metal, etc.), and properties of paint slurry and coating film of the ceramic paint. In the comparison of the ceramic paint with natural paint and mineral paint which were known as our environment-friendly paints, ceramic paint had good characteristics in the environmental safety and properies of wet slurry and dried coating film.