• Journal of Korean Dental Science
• /
• v.16 no.1
• /
• pp.74-79
• /
• 2023

Purpose: Cention N (Ivoclar Vivadent) was a recently introduced alkasite-based restorative material that was expected to replace amalgam and glass ionomer cement. This material was an esthetic restoration with adequate mechanical strength and release of fluoride and calcium. The purpose of this study was to measure the water sorption and water solubility of Cention N and evaluate its long-term durability compared to other esthetic restorations (Resin-Modified Glass Ionomer cement [RMGIC], Giomer, Composite Resin). Materials and Methods: Twenty specimens each of Cention N (CN), Resin Modified-Glass Ionomer Cement (FJ), Giomer (BF), and Composite Resin (FZ) were made. After each specimen was completely dried in a desiccator for 24 hours using a vacuum pressure pump, the specimen was weighed (m1). After that, the specimen was immersed in distilled water at 37℃ for 7 days, stored in a drying oven, and weighed (m2). After drying completely for 24 hours in a desiccator, the specimen was weighed (m3) to calculate the water absorption and water solubility using Formulas 1 and 2. The measured values were statistically processed and analyzed using SPSS, and the significance level was set at 0.05. Result: When measuring water sorption, FJ (122.61 ㎍/mm³) showed significantly higher water sorption than CN (35.42 ㎍/mm³) (P<0.05). There was no significant difference between FZ (18.03 ㎍/mm³) and BF (14.76 ㎍/mm³) (P=0.930). When measuring water solubility, CN (6.65 ㎍/mm³) showed significantly higher water solubility than FJ (1.47 ㎍/mm³) (P<0.05). Conclusion: Cention N had lower water sorption than RMGIC, but higher water solubility, indicating that it is more vulnerable to moisture and has lessened long-term durability.

• Food Science and Preservation
• /
• v.24 no.3
• /
• pp.464-471
• /
• 2017

The purpose of this study was to evaluate the effect of superheated steam drying on physicochemical and microbial characteristics of Korean traditional actinidia (Actinidia arguta) leaves. Actinidia leaves were dried at steam temperature of $350^{\circ}C$ and oven temperature of $150^{\circ}C$ for 40-200 sec. Moisture content and water activity decreased with increasing the drying time, while color values including L, a, and b values and total color difference (${\Delta}E$) increased as drying time increased. The relationship between moisture content and water activity showed an exponential fit with high correlation vlaue ($R^2=0.9909$). Total phenolics and flavonoids content and antioxidant activity such as DPPH radical scavenging activity, ABTS radical scavenging activity, and FRAP assay of dried actinidia leaves increased with increasing the drying time up to 160 sec, but dramatically decreased at drying of 200 sec. The numbers of total areobic bacteria of leaves was not detected at drying time over 120 sec and coliform of all the samples was not detected. As a results, the superheated steam was an very effective drying method of increase to the nutritional and sanitary quality of dried Korean traditional actinidia leaves.

• Journal of the Korean Wood Science and Technology
• /
• v.45 no.3
• /
• pp.258-267
• /
• 2017

In this study, pitch pine (Pinus rigida, PIR) and Mongolian oak (Quercus mongolica, QUM) pellets were fabricated with bark or/and drying waste liquor (DWL) of larch (Larix kaempferi, LAK) as an additive. Based on the results of fuel characteristics of the pellets, optimal conditions for producing the high-quality pellets were provided. In the analysis of chemical composition, bark contained holocelluose and lignin of 90% and over. DWL had 0.1% solid assumed to sugars which are generated from the oven-drying of LAK logs. QUM showed high ash content (2.2%) by containing of bark in the sawdust. Bark and DWL of LAK had high ash content of 4% and over. Calorific values of all specimens and additives were higher than that of the $1^{st}$-grade standard of wood pellets designated by NIFOS (18.0 MJ/kg). PIR and QUM pellets were fabricated with additive of 2 wt% based on the solid weight of oven-dried sawdust using a piston-type flat-die pelletizer, and thus ash content and calorific value of the pellets did not affect by the use of additive. Durability of the pellets increased with the use of additive. Durabilties of pellets, which were fabricated with bark as an additive and DWL as a controller of moisture content for sawdust, did not differ from those of pellets without additives and were lower than those of pellets either with bark or DWL. However, use of both bark and DWL for the production of wood pellets might be favorable because it can make a profit from the collection process of DWL. Based on the results of fuel characteristics of the pellets, QUM and PIR pellets were produced by a flat-die pelletizer. Moisture content (MC), bulk density and durability of the pellets improved with the use of additive. Particularly, sawdust MC of 10% and the addition of bark or DWL for PIR as well as sawdust MC of 12% and the addition of bark for QUM might be optimal conditions for the production of high-quality pellets. Except for the ash content of QUM pellets, other properties of PIR and QUM pellets exceeded the $1^{st}$-grade wood pellets standards of NIFOS.

• KSBB Journal
• /
• v.16 no.3
• /
• pp.233-236
• /
• 2001

Because of casehardenign effect of amorphous paclitaxel, residual solvents, methylene chloride and emthanol could not be reduced to the maximum value allowed, 600 ppm and 3,000 ppm, in accord with the guidelines issued by the International Conference on Harmonization (ICH, 1997), using rotary evaporation and successive drying in a vacuum oven. However, methylene chloride and methanol were reduced to 486 ppm and 403 ppm, respectively using supercritical $CO_2$ on purified paclitaxel. The optimum pressure and operating time were 80 bar and 30 min at fixed operating temperature ($40^{circ}C$). This approach serves as a novel application of supercritical fluid extraction to remove residual solvents from active pharmaceutical ingredients.

• Journal of Pharmaceutical Investigation
• /
• v.25 no.1
• /
• pp.37-46
• /
• 1995

The experiment was designed to investigate the sustained release dosage form of silymarin (SL) from chitosan (CS) carrier. Solid dispersed system was prepared by mixing the drug with chitosan. This solid dispersed system was cross-linked by glutaraldehyde, formaldehyde, acetaldehyde and butylaldehyde, respectively. The dissolution rates of these preparations were compared with each other in vitro. The silymarin was mired with anionic alginate gel and bead was prepared by dropping this mixture to cationic chitosan solution including calcium chloride. Chitosan encapsulated alginate bead after drying in the oven was investigated for the dissolution rate. The dissolution rate of SL-CS mixture was delayed with increase in the amounts of CS and the concentration of aldehyde. The effect on the delay of dissolution rate was in the increasing order of formaldehyde, glutaraldehyde, acetaldehyde, butylaldehyde. The dissolution rate of chitosan encapsulated alginate bead was parallel with the concentration of chitosan in diluted hydrochloric acid solution and delayed with increase in the concentration of chitosan in phosphate buffer solution.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.58 no.4
• /
• pp.476-482
• /
• 2009

This paper describes the development of capacitive sensor for the diagnosis of liquid dielectrics, which is widely used as the electrical insulating oil of transformer, circuit breaker, cable and etc. To survey the dielectric properties of the virgin and aged electrical insulating oils, we utilized the highly precise measuring system, using the principle of cross capacitance. The measured properties were used to determine the design factors of the sensor. Then the factors were optimized with the help of computational analysis. To evaluate diagnosis by the sensor, we performed accelerated thermal aging test about electrical insulating oils. The condition of aged specimens were investigated by measurements of relative permittivity i.e. capacitance change by capacitive sensor. And to evaluate the hysteresis characteristics with the change of temperature, we constructed a testing system, which was composed with vacuum drying oven, oil chamber and measuring instruments, such as LCR meter, MUX and so forth. Through the results of this investigation, we confirmed the superior characteristics of the newly developed sensor.

• 보존과학연구
• /
• s.6
• /
• pp.247-258
• /
• 1985

Conservation laboratory was attached to Keimyung University Museum inMarch 1980 and ever since it has been devoted mainly to the processing andconservation of metal objects. A number of objects have been processed inthis laboratory during the period, including those already in the collection ofthe Museum, those which were discovered during the three major excavationsof Kaya tombs conducted by the Museum, and those processed on commissionfrom other museums in the country,The activities of this laboratory include: (1) conserving the objects againstfurther erosion; (2) raising the archaeological value of the objects by revealingthe structure of such parts of the objects as concealed under rust; and (3)recovering the original shape of damaged objects.The methods adopted by the laboratory include: (1) removing from theobjects the ionized chlorine which usually are the major cause of erosion; (2)strengthening the objects by soaking them in acrylic resins; and (3) applyingresins to the surface of the objects to protect them from further erosion.Chemicals much employed by the laboratory includes the acrylic resin(Ruschot; developed jointly by the Cultural Property Research Institute ofKorea and Samwha Paint Company), the sodium sesquicarbonate, the sodiumhydroxide, the lithium hydroxide, and the benzotriazole.Major apparatus in the laboratory includes the vacuum immersion tank, theairbrasive, the ultrasonic cleaner, the pH-ion meter, the water bath, the zoomstereo microscope, the drying oven, and the drill.

• Journal of Ocean Engineering and Technology
• /
• v.14 no.3
• /
• pp.90-99
• /
• 2000

This study has been investigated about the influence of moisture environment properties in the unidirectional and cross laminated carbon fiber/epoxy and glass fiber/epoxy composites. As a results, it was found that the weight gain of water increased with the immersion time and the mechanical properties were decreased with the weight gain of water. And it was also shown that the mechanical properties of carbon fiber/epoxy laminates were better than those of glass fiber/epoxy laminates. And a gap of the mechanical properties between the two kinds of laminates was increasing with the immersion time in distilled water of 80$^{\circ}C $. Mechanical properties which decreased by moisture absorption in the CF and GF reinforced laminates were recovered up to some extent by drying in oven at 80$^{\circ}C $ for 10 days.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 1999.04b
• /
• pp.361-365
• /
• 1999

This study examined the effects of multiple recycling on deinkability and properties of recycled paper from laser computer printout (LCPO). First, alkaline paper with a 20% printed area was disintegrated by TAPPI standard disintegrator at room temperature. After dewatering, the pulp was flotated and dried in oven at80$^{\circ}C$ for 24 hrs. A sequence of wetting, disintegrating, flotating and drying was one recycling cycle and this cyclic treatment was repeated from zero to five times. The recycled handsheet dropped to 90% of the original brightness after five cycles, and lost the most brightness after five cycles, and lost the most brightness in the first two cycles. However, it had a gain of 10% in opacity after five cycles as the same as the case of nonprinting. And, in this study, the method for determining residual ink(toner) content in recycled handsheets ere established by means of SEM-EDX and Py-GC. The change of residual ink percentage on recycled paper showed the effect of recycling numbers on deinkability of waste paper. A slight decrease in deinkability was noted for the recycled handsheets, which may be due to the change of fiber surface free energy connected with fiber swelling.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2010.05a
• /
• pp.42.2-42.2
• /
• 2010

Recently, highly porous bone substitutes, which have interconnected open pore structure, have been focused on improving their mechanical properties and modifying their functions. Especially, it is highly required to develop functional gradient structured bone substitute which is available for controlling their material properties such as bioresorption rate and elastic modulus. Porous $ZrO_2$ scaffold was fabricated by the sponge replica method using PU sponge. After 3 times of dip coating and the subsequent oven drying, burning out and microwave sintering were carried out. Various $ZrO_2$-BCP powder mixtures were prepared depending on the ratio and coated on the $ZrO_2$ scaffold by dip coating process. X-ray diffraction analysis was performed to characterize the phase identification of the scaffolds. Microstructures of the bone substitutes were observed using scanning electron microscopy.