• Journal of Korean society of Dental Hygiene
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• v.23 no.6
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• pp.459-466
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• 2023

Objectives: The purpose of this study was to evaluate the physical properties and antibacterial activity of denture base resin with added silver sulfadiazine. Methods: Specimens were made from self-curing denture base resin and silver sulfadiazine as an inorganic antibacterial agent. For physical evaluation of the specimens, surface roughness, surface hardness, and contact angle were measured. Bacterial growth was assessed by optical densityat 600 nm (OD600) and colony forming units (CFU) measurements to confirm antibacterial activity. Results: There was no significant difference in surface roughness, surface hardness, and contact angle in the experimental group containing silver sulfadiazine compared to the control group. In contrast, the experimental group showed a significant decrease in antibacterial activity compared to the control group in terms of OD value. Analysis of CFU confirmed a significant decrease in colonies in the experimental group compared to the control group. Conclusions: Denture base resin containing silver sulfadiazine, an inorganic antibacterial agent, exhibited enhanced antibacterial activity without physical changes. In conclusion, the use of denture base resin containing inorganic antibacterial agents may be expected in the future.

• Journal of the korean academy of Pediatric Dentistry
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• v.51 no.2
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• pp.140-148
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• 2024

This study aimed to enhance the physicochemical properties of sodium iodide-based root filling materials, particularly solubility. In earlier developmental stages, the iodoform-containing paste exhibited high antibacterial efficacy but failed to meet only the solubility requirement among the ISO 6876 criteria. Therefore, this study focused on enhancing the physicochemical properties of the paste under development, particularly centering on reducing its solubility. Four experimental groups were established, including three control group. The previously developed D30 paste was named the Oil 33 group, and the control group was named the Vitapex^® group. The Oil 50 group, in which the oil content was increased, and the Oil 45L group, in which lanolin was incorporated. The physical properties (solubility, pH, flowability, and film thickness) of the four pastes were evaluated according to the ISO 6876 standards. No significant differences were observed between the Oil 45L and Vitapex^® groups in any of the physical property evaluations. While the Oil 33 and Oil 50 groups met the ISO 6876 standards for flowability and film thickness, the Oil 45L group met all the physical properties. However, reducing the overall oil content may be necessary to enhance the antimicrobial properties. The result of the physicochemical experiments showed that the Oil 45L group with the newly formulated composition and incorporated lanolin exhibited low solubility meeting the ISO 6876 standard of ≤ 3%. We were able to develop a paste with more stable solubility than previous iodide-based root-filling materials. Therefore, the oil content must be further adjusted to improve its antimicrobial properties. If other physical properties also meet the ISO 6876 standards and demonstrate excellent results in cytotoxicity tests, this root filling material could potentially replace existing options.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.372-375
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• 1996

In this paper, a designing method of model following control system for linear descriptor system with disturbances is proposed. The features of this method are:1) both the physical structure of the system and the physical system variables properties can be preserved because there is no necessary to make transformation of this system. 2) boundedness of internal states are proved by means of coprime factorization of descriptor system.

• Food Science of Animal Resources
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• v.37 no.1
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• pp.38-43
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• 2017

This study was conducted to investigate the physical and sensory properties of ice cream containing fermented pepper powder. Three ice cream formulas were manufactured: 1, control; 2, supplemented with 0.1% fermented pepper powder; and 3, supplemented with 0.2% fermented pepper powder. Formulas 2 and 3 had significantly higher viscosity and lower overrun than formula 1 (p<0.05). Additionally, ice creams supplemented with fermented pepper powder were harder and maintained their forms longer than the controls. 0.2% fermented pepper powder added ice cream had no pungency as much as that of control and overall sensory attribute was not significantly different from control. Therefore, ice cream containing fermented pepper powder maintained physical and sensory properties similar to the controls, and maintenance was better. It means fermented pepper powder ice cream can be utilized as the material of functional food (dessert).

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.41 no.6
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• pp.61-66
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• 2004

To make a guide line of property control of angiography equipments, we made standard evaluation sheet forms of facility and management of angiography suite, physical properties of angiography equipments, and image quality of film and then surveyed them at 29 hospital nationwide. Survey and development of standard evaluation sheet form of physical properties of angiography equipments. By using resolution & radiation dose, physical properties of angiography equipments of 49 in number nationwide were evaluated. Most of them (91%) had good performance.

• Journal of the Korean Society of Tobacco Science
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• v.21 no.1
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• pp.5-9
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• 1999

In recent years, the line of increase in policy on tobacco production triggered a rise in the loading volume per bulk curing barn, and manufacturers boosted the output of their blowers in order to prevent dirty leaves in the process of curing. for this reason, we studied the effect of the reducing air flow in bulk curing chamber from the color fixing stage to the stem drying stage of flue curing process on physical properties of cured leaves. The control of air flow was composed of the reducing air velocity of blower by means of a voltage regulator (slidac), and condition before color fixing stage was all the same with the conventional curing method. As a result, an effectiveness of improvement in the physical properties of cured leaves were observed. The leaves cured by this method were somewhat orange in color of upper stalk position, better bodied, and less brittle compared with the leaves produced by conventional curing. However, the leaves cured by this method had a little sharpness and harshness. As to the physical properties, there was decreased in occurrence of flat leaves than that of conventional ones. On the other hand, in case of reducing air flow during the curing process, increase of price per kg reached to about 5 % compared with those of conventional curing method.

• Journal of the Korean Wood Science and Technology
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• v.22 no.1
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• pp.44-53
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• 1994

This research was carried out to investigate the effect of paper sludge addition on formaldehyde emission, and physical and mechanical properties of UF-particleboard. In order to investigate the effect of paper sludge addition to resin, particleboards were bonded with urea-formaldehyde resins containing 5, 10, 15% paper sludge powders of three types(A Type: -200 mesh, B Type: -100~+200 mesh. C Type: -50~+100 mesh), based on weight of resin solid. Also the effect of paper sludge addition to furnish was studied from particleboards fabricated with ratios of sludge to particle of 5:95, 10:90, 15:85 based on oven-dry weight. Tests were conducted on the manufactured particleboards to determine formaldehyde emission, bending properties, internal bond strength and thickness swelling. The obtained results were summarized as follows: The addition of paper sludge powder to resin yielded a higher pH of cured resin. Formaldehyde emission decreased with the increase of paper sludge powder addition to resin and paper sludge composition ratio to furnish. Particleboard bonded with urea-formaldehyde resin containing paper sludge powder and particleboard mixed with paper sludge have similar bending properties(MOR, MOE) and thickness swelling compared with control particleboard. Internal bond strength of particleboards treated with paper sludge were lower than that of control particleboard. The use of paper sludge as scavenger was achieved reduction of formaldehyde emission without depression of physical and mechanical properties of particleboard. Also the use of paper sludge was able to concluded that there is possibility of partial substitution of wood particle materials.

• Transactions on Electrical and Electronic Materials
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• v.14 no.3
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• pp.148-151
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• 2013

The control of Ga doping in ZnO nanowires (NWs) by physical vapor deposition has been implemented and characterized. Various Ga-doped ZnO NWs were grown using the vapor-liquid-solid (VLS) method, with Au catalyst on c-plane sapphire substrate by hot-walled pulsed laser deposition (HW-PLD), one of the physical vapor deposition methods. The structural, optical and electrical properties of Ga-doped ZnO NWs have been systematically analyzed, by changing Ga concentration in ZnO NWs. We observed stacking faults and different crystalline directions caused by increasing Ga concentration in ZnO NWs, using SEM and HR-TEM. A $D^0X$ peak in the PL spectra of Ga doped ZnO NWs that is sharper than that of pure ZnO NWs has been clearly observed, which indicated the substitution of Ga for Zn. The electrical properties of controlled Ga-doped ZnO NWs have been measured, and show that the conductance of ZnO NWs increased up to 3 wt% Ga doping. However, the conductance of 5 wt% Ga doped ZnO NWs decreased, because the mean free path was decreased, according to the increase of carrier concentration. This control of the structural, optical and electrical properties of ZnO NWs by doping, could provide the possibility of the fabrication of various nanowire based electronic devices, such as nano-FETs, nano-inverters, nano-logic circuits and customized nano-sensors.

• Restorative Dentistry and Endodontics
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• v.41 no.4
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• pp.296-303
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• 2016

Objectives: The purpose of the present study was to evaluate the effects of proanthocyanidin (PAC), a crosslinking agent, on the physical properties of a collagen hydrogel and the behavior of human periodontal ligament cells (hPDLCs) cultured in the scaffold. Materials and Methods: Viability of hPDLCs treated with PAC was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The physical properties of PAC treated collagen hydrogel scaffold were evaluated by the measurement of setting time, surface roughness, and differential scanning calorimetry (DSC). The behavior of the hPDLCs in the collagen scaffold was evaluated by cell morphology observation and cell numbers counting. Results: The setting time of the collagen scaffold was shortened in the presence of PAC (p < 0.05). The surface roughness of the PAC-treated collagen was higher compared to the untreated control group (p < 0.05). The thermogram of the crosslinked collagen exhibited a higher endothermic peak compared to the uncrosslinked one. Cells in the PAC-treated collagen were observed to attach in closer proximity to one another with more cytoplasmic extensions compared to cells in the untreated control group. The number of cells cultured in the PAC-treated collagen scaffolds was significantly increased compared to the untreated control (p < 0.05). Conclusions: Our results showed that PAC enhanced the physical properties of the collagen scaffold. Furthermore, the proliferation of hPDLCs cultured in the collagen scaffold crosslinked with PAC was facilitated. Conclusively, the application of PAC to the collagen scaffold may be beneficial for engineering-based periodontal ligament regeneration in delayed replantation.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1597-1599
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• 2004

Carbon nanotubes (CNTs) are grown on the TiN-coated silicon substrate by varying the thickness of Ni and Invar426 catalyst layers at 600$^{\circ}C$ using an inductively coupled plasma-chemical vapor deposition (ICP-CVD). The Ni and Invar426 catalysts are formed using an RF magnetron sputtering system with various deposition periods. Characterization using various techniques, such as FESEM, HRTEM, and Raman spectroscopy, shows that the physical dimension as well as the crystal quality of grown CNTs are strongly changed by the kind and thickness of catalyst materials. It is also seen that Ni catalysts would be more desirable for vertical-alignment of CNTs compared with Invar426 catalysts. However, the CNTs using Invar426 catalysts display much better electron emission capabilities than those using Ni catalysts. The physical reason for all the measured data obtained are discussed to establish the relationship between structural properties and field-emissive properties of CNTs.