• Korean Chemical Engineering Research
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• v.48 no.1
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• pp.68-74
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• 2010

In this study, fluidized-bed pyrolysis has been conducted in order to recover the bitumen contained in the oil sand. Canada Alberta oil sand contains 11.9% of bitumen and the bitumen-derived heavy oil produced in fluidizedbed tends to be upgraded relative to the bitumen. The continuous operation has been performed using $N_2$ as a fluidization gas at 1 atm and $500^{\circ}C$ in a reactor of 170 cm height. The results showed 87.76% of bitumen conversion, where liquid products are 74.45% and gas products are 13.31%. $H_2$, $O_2$, CO, $CO_2$, $CH_4$, and NO and $C_1{\sim}C_4$ hydrocarbons in the gas products were analyzed by on-line gas analyzer and gas chromatography, respectively. The pyrolysis oil was analyzed by using proximate analysis, heavy metal analysis, SIMDIS, asphaltenes, and heating value. By SIMDIS analysis, naphtha was 11.50%, middle distillation was 44.83% and heavy oil was 43.66%. It was obvious that the pyrolysis oil was upgraded compared with bitumens.

• Journal of the Korean Magnetics Society
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• v.14 no.1
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• pp.33-37
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• 2004

Cu$_{0.1}$Fe$_{0.9}$Cr$_2$S$_4$ has been studied with Mossbauer spectroscopy, x-ray diffraction, vibrating sample magnetometer (VSM), and magnetoresistance (MR) measurement. The crystal structure was determined to be a cubic spinel with lattice parameter a$_{0}$=9.9880 $\AA$. The MR measurements show a semiconductor behavior below 110 K and metal behaved above 100 K. The temperature dependence of magnetization of Cu$_{0.1}$Fe$_{0.9}$Cr$_2$S$_4$ was reported. In addition to a large irreversibility between the zero-field-cooling (ZFC) and the field-cooling (FC) magnetization at applied field H=100 Oe, a cusp-like anomaly was observed in both the FC and ZFC curves. It shifted toward the lower temperature region with increasing magnetic field, and then showed convex type maximum at 110 K, under the applied field of 5 kOe. The Mossbauer spectra were measured from 15 K to room temperature. The asymmetric line broadening was observed for the sample Cu$_{0.1}$Fe$_{0.9}$Cr$_2$S$_4$, and it was considered to be dynamic Jahn-Teller relaxation. The charge state of Fe ions was ferrous in character. The unusual reduction of magnetic hyperfine field below 110 K was interpreted in terms of cancellation effect between the mutually opposite orbital current field (H$_{L}$) and Fermi contact field (H$_{C}$).

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.3
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• pp.191-197
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• 2012

Esthetics is important in restoring maxillary anterior area. Alveolar bone resorption and loss of interdental papilla may be minimized by immediate implantation. Previous studies showed successful results with the immediate implantation in healthy extraction socket, while many of these studies objected the immediate implantation into extraction sites with periapical lesions. Recent studies, however, reported successful results of the immediate implantation into extraction sites with periapical lesions with careful debridement of extraction sockets and general medication of antibiotics prior to implantation. A 73-year-old female visited the department of Prosthodontics in ${\bigcirc}{\bigcirc}$ University Dental Hospital with the chief complaint of fallen post-core and crown on left maxillary incisor. Although the incisor was with vertical root fracture and periapical lesion, the immediate implantation following the extraction of tooth was planned. Thorough socket debridement, irrigation with chlorhexidine, and tetracycline soaking were followed by immediate implantation. The general medication of antibiotics (Moxicle Tab.$^{(R)}$, 375 mg) was prescribed before and after the surgery. Immediate provisional restoration was delivered two days after the surgery, and the definitive metal-ceramic restoration was placed about six months later after reproducing the emergence profile from the provisional restoration. This case presents satisfying result esthetically and functionally upto two years after the placement of prosthesis with the harmonious gingival line and no loss of marginal bone.

• Journal of Environmental Health Sciences
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• v.33 no.6
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• pp.506-512
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• 2007

This study was conducted to describe the exposure levels of welding fumes by the type of manufacturers, work process, welding type and the size of manufacturers, and to find out the trend of chronological changes of airborne welding fume levels. The subjects of this study were 509 manufacturers, consisting of 11 types of manufacturers, 3 work processes, 7 welding types, in Busan from January, 1997 to December, 2005. Airborne concentration of welding fume was determined by manual of National Institute for Occupational Safety and Health (NIOSH), and the data were analyzed by using SPSS 10.0 for Windows program. The mean concentration of airborne welding fume in all manufacturers was $1.29\;mg/m^3$ (Range: $0.01{\sim}3.00\;mg/m^3)$. The level of welding fume was the highest, as $1.96\;mg/m^3$, for manufactures of motor vehicles, trailers and semi-trailers, which was lower than $5.0\;mg/m^3$ of 8 hr-TWA in Korean permissible exposure limit for welding fume. There was a significant difference in the mean levels of welding fumes by work process, showing the highest in welding workshop ($1.39\;mg/m^3$), followed by pipeline welding workshop ($1.26\;mg/m^3$) and engineering workshop ($1.20\;mg/m^3$). Among welding types, the mean level of welding fume was the highest in the type of $CO_2$ & arc welding, as $1.46\;mg/m^3$, followed by $CO_2$ welding ($1.40\;mg/m^3$), shielded metal arc welding ($1.31\;mg/m^3$), spot welding ($1.27\;mg/m^3$), and so on. The highest mean level of welding fume was $1.58\;mg/m^3$ in work process of pipe line welding workshop for the manufacturers of basic iron and steel, and $2.27\;mg/m^3$ in the type of arc welding for the manufactures building ship and boats. By the size of manufacturers, the mean concentration of welding fume for manufactures in small scale with less than 50 workers was the highest as $1.45\;mg/m^3$ (Range: $0.07{\sim}3.00\;mg/m^3)$. The mean level of welding fume was the highest as $1.39\;mg/m^3$ both in 1997 and in 2005, showing a trend of fluctuating periodically within a range of $1.10{\sim}1.39\;mg/m^3$. The above results suggested that more effective control program for work environment producing welding fumes should be developed and applied since there were significant variations in welding fume levels by the type of manufacturers, work processes, welding types, the size of manufactures, and by year.

• The Research Journal of the Costume Culture
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• v.16 no.6
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• pp.1050-1063
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• 2008

A movie is a fiction made on a basis of an author's and a writer's imagination, but all sorts of properties mixed with each other and most realistically expresses the era which becomes the background of a movie and acts as a carrier that connects designers with consumers. Thus, this study was carried out to review how the fashion products that designer's intention and commercial value added are expressed in collections by comparing and analysing the costumes in the movie "The Great Gatsby" that described the life of America's upper-class in 1920s and the 04 S/S Y&Kei collection which were proceeding after getting inspiration from this movie. For this, literature materials were inspected in order to make a theoretical review on social and cultural background and costumes history background in 1920s and the photo materials on movie costume were collected and analysed using DVD video captures, as well as the photo materials on 04 S/S Y&Kei were collected and analyzed through the institute providing domestic fashion information. The following conclusion was deduced through this study. First, in 1920s which becomes the background of this study, the slim shape of Flapper which looks like a young and boy became an ideal figure condition and the straight silhouette with low waist line and the short skirt that rose to knee was popular. Second, as a result of analysing movie costume by classifying it in silhouette, colors, and materials, straight silhouette of low waistline with a near colored - tone seen in the pastel series, including white, beige, pink, and gray was mainly constituted and the metal colors like silver and gold were used. As a material, chiffon, satin, velvet, flower patterned prints, and beads were used, which represented luxurious life of women in the upper classes. Third, as a result of comparing and analysing, it turned out that there was a similarity. However, in dress collection for a heroine, some dissimilarity differentiated from a movie costumes was found out in that the dresses in collection expressed moderate beauty and modernism and elegant beauty at the same time by matching a variety of materials and using black color.

• Herbal Formula Science
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• v.16 no.2
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• pp.1-9
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• 2008

Objective : The purpose of this report was to provide the information about activity and safety of Ojeok-san by analyzing domestic/international papers about Ojeok-san. Methods : Domestic/international papers related to Ojeok-san were reviewed and analyzed. These papers were then classified by year, experimental method and subject. Results : The following results were obtained in this study. 1. The studies of Ojeok-san started from 1984 and has continuously increased. The studies were mainly focused on experimental models rather than clinical studies. 2. By subject, papers related to safety were most common with 5 papers among 20 papers. Besides there were papers related to efficacy of analgesic, anti-hyperlipidemic, anti-blood stasis and treatment for uterine myoma. 3. The papers related to safety were mainly focused on the effect of Okeok-san on liver function, renal function or metal concentration of organs such as blood, brain, liver, kidney and bone. Ojeok-san proved to be safe, but more clinical studies regarding the safety are needed hereafter. 4. Papers related to analgesic, anti-pyretic, anti-phlogistic activities of Ojeok-san were in vivo studies, and other papers were about anti-hyperlipidemic activity, apoptosis inducing activity on uterine myeloma cell line and anti blood static activity on hydrocortisone acetate induced blood statis model. 5. Case reports were about anti-lipidemia, analgesic effect for mastalgia/back pain and anxiety disorder due to climacteric changes. Conclusion : Ojeok-san is being used in various ways with analgesic, anti-pyretic, anti-phlogistic, anti-hyperlipidemic, anti-tumor or anti-blood statis activity. However, mechanism study should be conducted at the molecular biology level and more clinical studies on the efficacy of Ojeok-san are needed.

• The Journal of the Petrological Society of Korea
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• v.3 no.3
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• pp.185-195
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• 1994

An experimental study of iron-aluminium partitioning between synthetic garnet and synthetic epidote was carried out, as equilibrium was maintained in the exchange reaction expressed as follows : $Ca_3Fe_2Si_3O_12\+\2\Ca_2Al_2AlSi_3O_12$(0H) = $Ca_3Al_2Si_3O_12\+\Ca_2Al_2FeSi_3O_12$(0H) Temperature has a pronounced effect on the distribution of Fe and A1 between the minerals. However, the pressure effect is not so drastic as in the exchange reaction. With increasing temperature, $Fe^{+3}$ becomes redistributed from garnet into epidote, whereas A1 becomes redistributed from epidote into garnet. This is in line with the general principle of phase correspondence, as the temperature increases the more electropositive metal aluminium redistributes from epidote into garnet. The agreement between the experimental results of this study and the natural samples suggests that $K_D=X^{Ep}_{Fe}/X^{Gr}_{Fe}$ may be a useful geothermometer for metamorphic rocks containing garnet and epidote that are close to binary Fe-A1 compounds.

• Korean Journal of Environmental Biology
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• v.34 no.3
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• pp.193-200
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• 2016

Toxicity assessment of heavy metals (As, Cr and Pb) has been investigated by using the rate of survival and population growth(r) of marine rotifer, Brachionus plicatilis. The survival rate was determined after 24 hours of exposure to As, Cr and Pb. As and Cr reduced survival rate in dose-dependent manner and a significant reduction were occurred at concentration of greater than 30 and $150mg\;L^{-1}$, but Pb had no effect on survival rate. The r was determined after 72 hours of exposure to As, Cr and Pb. As, Cr and Pb reduced r in dose-dependent manner and a significant reduction were occurred at concentration of greater than 5, 25 and $50mg\;L^{-1}$. The toxicity of heavy metals were ranked As>Cr>Pb, with $EC_{50}$ values of 12.98, 82.34 and $110.14mg\;L^{-1}$, respectively. The no-observed-effect-concentration (NOEC) of r in As, Cr and Pb exposure were 1, 12.5 and $50mg\;L^{-1}$, respectively. The lowest-observed-effect-concentration (LOEC) of r in As, Cr and Pb exposure were 5, 25, and $50mg\;L^{-1}$, respectively. From the results, the concentration of As, Cr and Pb (greater than 5, 25 and $50mg\;L^{-1}$, respectively) have toxic effect on the r of B. plicatilis in natural ecosystems. These results (including NOEC and $EC_{50}$) might be useful for the mixing toxicity assessment and toxic guide line of heavy metals in marine ecosystems.

• Journal of Dental Rehabilitation and Applied Science
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• v.16 no.1
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• pp.13-25
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• 2000

Optimal Pressable Ceramic is one of the all-ceramic restorations with a shaded translucent pressed core and layering porcelains. The purpose of this study was to evaluate the marginal fidelity according to margin types and measurement sites, and to evaluate fracture strength according to margin types. Twenty seven OPC crowns made according to 3 types of cervical finishing lines were used in this study. Marginal gaps were measured before and after cementation. A Steromicroscope(SZ-ST(R), Olympus, Japan) was used to measure the space between the margin of OPC crown and the finishing line of metal model. Marginal gaps were measured at the labial, mesial, lingual and distal site, which were demonstrated in advance. Fracture strength testing was carried out using an Instron(Model M100EC, Mecmesin, England) at a cross head speed of 5 mm/min. All crowns were loaded until catastrophic failures occurred. The result were as follow: 1. In comparison according to variable margin before cementation, the marginal gap were increased in chamfer margin($47.50{\pm}18.39{\mu}m$), $120^{\circ}$shoulder margin ($55.21{\pm}14.4{\mu}m$) and $90^{\circ}$shoulder margin($71.18{\pm}13.30{\mu}m$) in ascending order, and there were significant differences between chamfer margin and $90^{\circ}$shoulder margin, $120^{\circ}$shoulder margin and between $120^{\circ}$shoulder margin and $90^{\circ}$shoulder margin respectively(p<0.05). 2. In comparison according to variable margin after cementation, the gap discrepancies were increased in chamfer margin($60.78{\pm}30.37{\mu}m$), $120^{\circ}$shoulder margin($66.67{\pm}11.18{\mu}m$) and $90^{\circ}$shoulder margin($85.78{\pm}17.23{\mu}m$) in ascending order, but there was significant difference only between chamfer margin and $90^{\circ}$shoulder margin(p<0.05). 3. Labio-lingual points showed a better marginal fidelity than that of proximal point(p<0.05). 4. Chamfer margin($48.76{\pm}8.45kgf$) showed higher fracture strength than $120^{\circ}$ shoulder margin($40.57{\pm}7.90kgf$) and $90^{\circ}$ shoulder margin(32.7.90kgf) (p<0.05), but there was significant difference only between chamfer margin and $90^{\circ}$ shoulder margin(p<0.05).

• Restorative Dentistry and Endodontics
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• v.13 no.2
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• pp.337-348
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• 1988

The purpose of this study was to examine the fracture strength and characteristics of teeth with MOD cavity preparation. Freshly extracted sound maxillary premolars were cleaned and stored in normal saline solution $37^{\circ}C$ for 72 hours before experiments. The roots of teeth were embedded in a self-curing resin, and the exposed crown were maintained in a vertical position by a modelling wax in a brass ring. The MOD cavities were prepared with No. 57 carbide bur under high speed to a depth of 2.0mm and a width of 2.0mm(Fig.1). All the prepared teeth specimens were divided into 7 groups according to the mode of cavity form and restorative materials (Table 1, 2): Group I, unpreapred, intact teeth as control Group II, prepared cavity without restoration Group III, prepared teeth restored with amalgam Group IV, prepared teeth restored with composite resin (P-10) Group V, prepared teeth with beveled enamel margins restored with composite resin (P-10) Group VI, prepared teeth restored with light-cured composite resin (P-30) Group VII, prepard teeth with beveled enamel margins restored with light-cured composite resin (P-30) After placement of restorations, all of the specimens were stored in water at $37^{\circ}C$ for 72 hours before testing. All of the specimens were tested on the Instron Universal Testing machine (No. 6025) in order to evaluate the strength of fracture. One metal ball 5.0mm in diameter contacting the specimens parallel to the occlusal surface was used to in this study (Fig. 1). The fracture characteristics of the specimens were examined with naked eye and in the scanning electron microscope (JSM-20). The results obtained from this study were as follows: 1. The mean fracture strength was the highest in group VI and that in group II was the lowest. 2. The progress of crack of teeth propagated into the pulp cavity. 3. In case of the group of the restored teeth, the crack occurred to be accompanied with cuspal fracture. 4. The crack of restored teeth was initiated along the pulpo-axial line angle of the cavity.