• The Journal of Korean Academy of Prosthodontics
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• v.45 no.5
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• pp.601-610
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• 2007

Statement of problem: The adhesion between titanium and ceramic is less optimal than conventional metal-ceramic bonding, due to reaction layer form on cast titanium surface during porcelain firing. Purpose: This study characterized the effect of titanium-ceramic adhesion after gold and TiN coating on cast and wrought titanium substrates. Material and method: Six groups of ASTM grade II commercially pure titanium and cast titanium specimens$(13mm{\times}13mm{\times}1mm)$ were prepared(n=8). The conventional Au-Pd-In alloy served as the control. All specimens were sandblasted with $110{\mu}m\;Al_2O_3$ particles and ultrasonically cleaned for 5min in deionized water and dried in air before porcelain firing. An ultra-low-fusing dental porcelain (Vita Titankeramik) was fused on titanium surfaces. Porcelain was debonded by a biaxial flexure test at a cross head speed of 0.25mm/min. The excellent titanium-ceramic adherence was exhibited by the presence of a dentin porcelain layer on the specimen surface after the biaxial flexure test. Area fraction of adherent porcelain (AFAP) was determined by SEM/EDS. Numerical results were statistically analyzed by one-way ANOVA and Student-Newman-Keuls test at ${\alpha}=0.05$. Results: The AFAP value of cast titanium was greatest in the group 2 with TiN coating, followed by group 1 with Au coating and the group 3 with $Al_2O_3$ sandblasting. Significant statistical difference was found between the group 1, 2 and the group 3 (p<.05). The AFAP value of wrought titanium was greatest in the group 5 with TiN coating, followed by the group 4 with Au coating and the group 6 with $Al_2O_3$ sandblasting. Conclusion: No significant difference was observed among the three groups (p>.05). The AFAP values of the cast titanium and the wrought titanium were similar. However the group treated with $Al_2O_3$ sandblasting showed significantly lower value (p<.05).

• Restorative Dentistry and Endodontics
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• v.24 no.3
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• pp.465-472
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• 1999

The aim of this study was to determine the shear bond properties of four dentin bonding systems to internal cervical dentin, and to investigate the effect of the pretreatment for removing smear layer and position of dentin on shear bond strength of dentin bonding agents. The materials tested in this study were consisted of four commercially available dentin bonding systems[Allbond 2(AB), Clearfil Linerbond 2(CL), Optibond FL(OP), Scotchbond Multi-purpose(SB)], a restorative light-cured composite resin[Z100]J and a chelating agent[RC-prep(RC)]. Fifty-six freshly extracted human molars were used in this study. Dentin specimens were prepared by first cutting the root of the tooth 1mm below the cementoenamel junction with a diamond bur in a high speed handpiece under air-water coolant, and then removing occlusal part at pulp horn level by means of a second parallel section, The root canal areas were exposed by means of cutting the dent in specimens perpendicular to the root axis. Dentin specimens were randomly assigned to two groups(pretreated group, not-pretreated group) based on the pretreatment method of dentin surface. In pretreated group, RC was applied to dentin surface for 1minute and then rinsed with NaOCl. In not-pretreated group, dentin surface was rinsed with saline Each groups were subdevided into four groups according to dentin bonding systems. Four dentin bonding systems and a restorative resin were applied according to the directions of manufacturer. The dentin-resin specimens were embedded in a cold cure acrylic resin, and were cut with a low speed diamond saw to the dimension of $1{\times}1mm$. The cut specimens were divided into three groups according to the position of internal cervical dentin. The shear bond properties of dentin-resin specimens were measured with Universal testing machine (Zwick, 020, Germany) with the cross head speed of 0.5mm/min. From this experiment. the following results were obtained : 1. In case of shear bond strength, there was no significant difference among dentin bonding systems in not-pretreated groups, whereas in pretreated groups, the shear bond strengths of AB and of SB were statistically significantly higher than those of CL and of OP. 2. The shear bond strengths of AB and of SB in pretreated groups were significantly higher than those in not-pretreated groups. 3. The shear bond strengths of radicular layer of OP were higher than those of occlusal layer of OP in not-pretreated groups, and of AB in pretreated groups. The shear bond strengths of radicular layer of AB and of CL in not-pretreated groups were higher than those in pretreated group.

• Restorative Dentistry and Endodontics
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• v.22 no.2
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• pp.609-621
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• 1997

The purpose of this study was to evaluate the shear bond strength of three light-cured glass ionomer cements to blood contaminated bovine dentin. The materials used in this study were Fuji II LC, Dyract and Variglass VLC. The dentin conditioners were 10% polyacrylic acid, 10% maleic acid and 10% phosphoric acid. 180 lower anterior bovine teeth were selected in this study. The teeth were embedded in acrylic resin and were grounded with 320 to 600 grit silicon carbide paper to create a flat dentin surface. The teeth were divided into SIX groups. The experimental procedures in six groups were as follows; Group l(GF) : Samples bonded to dentin surface with Fuji II LC after 10% polyacrylic acid treatment. Group 2(BGF) : Samples bonded to dentin surface with Fuji II LC after 10% polyacrylic acid treatment and blood contamination. Group 3(MD) : Samples bonded to dentin surface with Dyract after 10% maleic acid treatment. Group 4(BMD) : Samples bonded to dentin surface with Dyract after 10% maleic acid treatment and blood contamination. Group 5(PV) : Samples bonded to dentin surface with Variglass VLC after 10% phosphoric acid treatment. Group 6(BPV) : Samples bonded-to dentin surface with Variglass VLC after 10% phosphoric acid treatment and blood contamination. Group 1,3 and 5 were classified into the control groups, while group 2,4 and 6 were classified into the experimental groups. Each group contained 30 samples. After 24 hours water storage at $37^{\circ}C$, all smples were subjected to a shear load to fracture at a cross head speed of 1.0 mm/min with Instron universal testing machine(No. 4467). Debonded surfaces were observed under Scanning Electron Microscope(Hitachi S-2300) at 20kvp. The data were evaluated statistically at the 95% confidence level with Student's t-test. The following results obtained; 1. Shear bond strengths were higher in the control groups(1,3,5 group) than in the experimental groups(2,4,6 group). 2. The shear bond strength of group 5(PV) was the highest in the control groups, and the group 5 was significantly higher than the group l(GF) on the shear bond strength. 3. The group 4(BMD) was the highest on the shear bond strength, and the group 2(BGF) was the lowest in the experimental groups. The group 4(BMD) and 6(BPV) showed a significant difference with the group 2 on the shear bond strength. 4. All the groups showed an adhesive-cohesive failure. except the group 2(BGF) showing adhesive failure.

• Restorative Dentistry and Endodontics
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• v.22 no.2
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• pp.751-760
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• 1997

Resin-modified glass ionomers were introduced in 1988 to overcome the problems of moisture sensitivity and low early mechanical strengths of the conventional glass ionomers, and to maintain their dinical advantages. The purpose of this study was to evaluate the bi-axial fracture strength of four resinmodified glass-ionomers(Fuji II LC, Vitremer, Dyract, VariGlass), one resin composite material(Z-100), and one conventional glass-ionomer(Fuji II). Three specimens of each material and shade combination were made according to the manufacturers' instructions. Materials were condensed into metal mold with a diameter of 10mm and a thickness of 2.0mm and pressed between two glass plates. Resin-modified glass ionomers were polymerized using a Visilux II light curing unit by irradiating for 60 seconds from both sides, and conventional glass ionomer was cured chemically. After specimens were removed from the molds, surfaces were polished sequentially on wet sandpapers up to No. 600 silicone carbide paper. The specimens were thermocycled for 2,000 cycles between $5^{\circ}C$ and $55^{\circ}C$ distilled water. After thermocycling, bi-axial fracture strengths were measured using a compressive-tensile tester(Zwick 1456 Z020, Germany) with the cross head speed of 0.5mm/minute. The results were as follows: 1. Two factors of the kind and color of materials had a main effect on bi-axial fracture strength (p<0.01), and bi-axial fracture strength was influenced significantly by the kinds of materials (p<0.01). But there was no significant interaction between two variables of the kind and color of materials (p>0.05). 2. Comparing the mechanical properties of the materials, the elastic modulus of Z100 was higher than any other material, and there was no difference in the displacement at fracture among materials. The bi-axial fracture strength of Z100 was significantly higher than any other material, and that of resin-modified glass ionomers was significantly higher than that of conventional glass ionomer (p<0.05). 3. In the same material group, the color of material had little influence on the mechanical properties.

• Applied Biological Chemistry
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• v.34 no.3
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• pp.258-261
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• 1991

In order to establish the optimum drying temperature of the heated air blast-grain circulation dryer, a 2 ton scale of paddy was used in this experiment. The temperatures of heated air used were 45, 50, 55, 60, 65 and $70^{\circ}C$. Moisture content of the paddy was reduced to 15% from 24% by drying. The higher air temperature, the shorter drying time and the less fuel consumed. The portion of cracked kernels was found to be low as $3{\sim}10%\;at\;40{\sim}55^{\circ}C$, but was very high to $28{\sim}30%\;at\;60{\sim}70^{\circ}C$. The germination percent was very high as 98 and 93% at 40 and $45^{\circ}C$, but it was decreased to 86 and 30% at 50 and $70^{\circ}C$, respectively. The recovery yield of milled rice from paddy was decreased by 1.76, 2.63 and 7.52% at 60, 65 and $70^{\circ}C$, respectively, compared with 75.86% as drying at $40^{\circ}C$. The higher heated air temperature, the less head rice of milled rice was recovered, and the decreased ratio was increased $60^{\circ}C$. The higher heated air temperature, the less alkali disintergation value and gel consistency of milled rice and the more water up take, expanded vlume, total solid in residual liquid and intensity of starch iodine blue value of residual liquid, and those tendency was found clear from $60^{\circ}C$ temperature of heated air.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.5
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• pp.525-534
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• 2005

A column experiment was performed to investigate the influence of the sludge cake development on the riverbed and the hydraulic gradient imposed by the drawdown at the well on the filtrate quality in order to offer a guideline in the design and operation of the riverbed filtration. Results show that the sludge cake on the riverbed plays an important role in the removal of the organic matter. Under the conditions of this study the COD removal rate increased from 17% to 50% along with the sludge cake development, which was equivalent to the BCOD removal of 22% and 67%, respectively. The active removal of the organic matter took place in the sludge cake and the upper 40 cm of the riverbed. As the flow rate increased owing to the increase in the head difference imposed on the column, the slope of the COD profile near the column inlet decreased, however, the profiles converged in about 40 cm from the inlet. In 10 days of sludge cake formation the dissolved oxygen was depleted at the depth of 70 cm, which suggests the denitrification can take place beyond the depth. This depth was further reduced to $20{\sim}40\; cm$ as the sludge cake developed. From this study the removal of organic matter can be expected through the riverbed filtration even with the depth of as shallow as 3 m, which is frequently met in Korea, while the removal of nitrogen through denitrification is not expected to be active under the condition.

• Journal of Ginseng Research
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• v.11 no.2
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• pp.145-252
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• 1987

Isolated rat adipocytes are well known to possess opposite pathways of lipid metabolism: lipolysis and ipogenesis. Both of the metabolism respond to various biologically active substances such as epinephrine, ACTH and insulin. Epinephrine and ACTH stimulate lipolysis and insulin accelerates lipogenesis. Recently, Korean red ginseng powder was found to contain adenosine and an acidic poptide which inhibited epinephrine-induced lipolysis and sl imulated insulin-mediated lipogenesis from added glucose. The acidic peptide is consisted mainly of glutamic acid and glucose. Ginsenosides Rb1 and Re inhibited ACTH-induced lipolysis in isolated rat adipocytes, while they did not affect insulinstimulated lipogenesis, Thus, all these substances extracted from Korean red ginseng exhibited selective modulations toward the opposite metabolic pathways in rat adipocyte; They inhibited the lipolysis but not the lipogenesis. We call these substances"selective modulators". Recently, we isolated a toxic substance named "toxohormone-L " from ascites fluid of patients with various malignant tumors. The toxohormone-L stimulated lipolysis in rat adipocytes and induced anorexia in rats. Both the lipolytic and the anorexigenic actions of toxohormone-L were found to be inhibited by ginsenoside Rb2 in Korean red ginseng. Based on these results, physiological signifi¬cances of these substances in Korean red ginseng were discussed. Pan ax ginseng is a medicinal plant long used in treatment of various pathological states including general complaints such as head ache, shoulder ache, chilly constitution and anorexia in cancer patients, There have been many pharmacological studies on Panax ginseng roots. Petkovllreported that oral administration of an aqueous alcoholic extract of ginseng roots decreased the blood sugar levtl of rabbits. Saito2lreported that Panax ginseng suppressed hyperglycemia induced by epinephrine and high carbohydrate diets. These findings suggest that Panax ginseng roots contain insulin-like substances. Previously, we demonstrated that gin¬seng roots contain an insulin-like peptide which inhibits epinephrine-induced lipolysis and stimulated insulin-mediated lipogenesis. In 1984, we suggested that such an insulin-like substance should be called a selective modulator4). Present investigation describes the details of the selective modulators in ginseng roots. During progressive weight loss in patients with various neoplastic disease, depletion of fat stores have been observed. The depletion of body fat during growth of neoplasms is associated with increase in plasma free fatty acids. Recently, we found that the ascites fluid from patients with hepatoma or ovarian tumor and the pleural fluid from patients with malignant lymphoma elicited fatty acid release in slices of rat adipose tissue in vitro. The lipolytic factor, named"toxohormone-L". was purifed from the ascites fluid of patients with hepatoma. The isolated preparation gave a single band on both disc gel electrophoresis and sodium dodecyl sulfate(SDS)-acrylamide gel electrophoresis in the presence of ${\beta}$-mercaptoethanol. Its molecular weight was determined to be 70,000-75,000 and 65,000 by SDS-acrylamide gel electrophoresis and analytical ultracentrifugation, respectively. Injection of toxohormone-L into the lateral ventricle of rats significantly suppressed food and water intakes. There was at least 5 hr delay between its injection and appearance of its suppressive effect. In the present study, we also tried to find a inhibitory substance toward toxohormone-L from root powder of ginseng.

• Korean Journal of Ichthyology
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• v.26 no.4
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• pp.267-273
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• 2014

This research has carried out to make a data base of taxonomic research. That Data base explains about spawning behavior, egg development, and morphologic development of variable sabretooth blenny. Fertilized egg was demersal egg which is white and opaque. The number of oil glouble were 10~11, and the size of egg was 0.90~1.43 mm (average rate $1.11{\pm}0.23mm$, n=10). Breeding water temperature was $25.5{\sim}28.5^{\circ}C$ (average rate $27.0^{\circ}C$), and salinity was 32.5~33.5‰ (average rate 33.0‰). After 24 hours from 2 cells, the process of egg development was reached to Blastula stage. Moreover, after 330 hours from 2 cells, nostrils and eyes were formed. Egg membrane was pierced by the head, and the hatch began. After the hatch, postlarvae had 2.59~3.02 mm (average rate $2.81{\pm}0.25mm$, n=5) of whole length, and the mouth and anus were opened. Yolk sac and oil glouble were absorbed. After three days from hatch, prelarvae were 3.02~3.07mm(average rate $3.04{\pm}0.04mm$) of whole length, and caudal fin was grown with round shape. After 13 days from hatch, prelarvae had 3.04~3.20 mm (average rate $3.12{\pm}0.11mm$) of whole length, and they could eat food with upper jaw and bottom jaw.

• Journal of the Korean Institute of Landscape Architecture
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• v.26 no.4
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• pp.82-94
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• 1999

According to Korean's geographical features of Taek Li Ji, the best location for human settlements is on the vicinity of a stream among a stream, an river and a sea, and not far from a ridge. The researcher chose one of best village which is called Yougokmaeul in Bonghwa-Gun, Kyungsang-Do. This village was created a gathering village with the same surname, can be translated as a hen and the front mountain can be seen as a rooster in the view of the shape of geographical features. As it were, the shape of this village and the cultivated land seems to be an egg inside a nest of a parent's chicken in the respect of the analogy of the theory of P'ungsuchiri which is known as Feng Shui in China and geomancy in the western world, and to effect the defensive psychology of the living environment in the terrain inland. This village is the studying place, Suckchunjungsa as the lecturing and studying place for their following students within the Chunghadonchun, the studying Yougok village, and even the ritual place performing ancestral sacrifices and the first incoming ancestor's graves in the same geographical system. The house site of the first incoming resident is surrounded the countian and is located in the front of Backsulryount which is the main mountain through Moonsu-san in the branch mountain of Korean's mountain system. Backsulryoung which is to be seen as the white peak, is symbolized the head of a hen which is to relate to a mysterious turtle in the view of P'ungsuchiri. And the pavilion which is called Chungamjung is sited on the rock of a shape of turtle which is symbolized to live longer. In the section of the mountain and water, Lee Jung Hwan mentioned a living place near the mountain stream is the best residential area and a landscape which is composed by a stream between mountains make a pleasure spirit and a bright feeling and make a refined person. If one can reach in the graceful mountain make a pleasure split and a bright feeling and make a refined person. If one can reach in the graceful mountain half day away, this kind of place must be a best living residential area to live. But this village was structured all in one place. And one of the ideas tangibly reflected in traditional Korean society's view of life and nature is the seclusion based on the Taoism. This kind of a dreamy thoughts make a dream to keep the paradise in our ancestors' mind. This kind of utopia is Chunghadonchun which is structured 5 aspects from the utopian gate near the Samgaesuewon to the village. These 5aspects is expressed by some Confucian thoughts as a small cosmos individually. On the third aspects which is the center among these aspects, the Suckchunjungsa which was made a seclusion place to devoting himself to his studies with refined tastes. The word of Jiju-am, Gangpung-dae, Jaewol-dae and Biryoung-pock are all expressed to cultivate one's moral character and to seek the truth by the Confucius'theory through the nature.

• Progress in Medical Physics
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• v.9 no.2
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• pp.89-94
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• 1998

To make practical application of the MR image for stereotactic radiosurgery, the target point-achieved by acquisition of MR image in stereotactic radiosurgery planning system must agree with the actual isocenter of irradiation in real treatment. And the amount of distortion of the MR image must be known to make a correction for the agreement. A radish containing abundant water content was chosen as a homogeneous phantom for the purpose of verification of the agreement in this experiment. A dosimetric film was firmly attached to the small specially fabricated acryl plate and needle puncture was made through the film just into the acryl plate and a drop of oil was dropped into the hole of the film. The acryl plate with film was inserted into the radish and the dorp of oil represented the target point in MR image. After the image acquisition by stereotatic radiosurgery planning system, we achieved stereotactic coordinate of the target point represented by the oil drop. And we proceeded to actual irradiation to the target point according to the procedure of stereotactic radiosurgery. After the irradiation, the film in the radish was developed and processed and the degree of coincidence between the center of the radiation distribution and the target point represented by the hole in the film was measured. The discrepancy between two points was under 0.5 mm. so we could confirm good coincidence in homogeneous phantom such as radish. On the other hand, authors tried to use our home-made device for estimation of distortion of MR image.