• Journal of Korean society of Dental Hygiene
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• v.8 no.1
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• pp.119-131
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• 2008

This study was peformed in order to find out the relationship between the causing factors and the production of each gas 01 oral malodor, to contribute the oral malodor control at dental clinic as well as to establish the effective application of malodor control project for public oral health program 127 patients from 20 to 40 years old who had been visited for preventive dental cares were participated for the study. Such items as caries status, periodontal status, salivary flow, viscosity, pH. Snyder test, plaque deposit and tongue plaque were checked through the oral examination in order to find out the contributing factors Hydrogen sulfide, Methyl mercaptan, Di-methyl sulfide and Ammonia gas components were checked with Oral-Chroma and Attain, the oral malodor check units. Not only the corelation coefficiencies but also the multi-way variance analysis were calculated between each causing factor and each component of oral malodor gases to estimate the contributing factors of the oral malodor. 1. There was no relationship between the caries status and each component pf the oral malodor such as sulfur compound or Ammonia, both in laboratory test and VAS test (pF0.05). It revealed negative relationship between Hydrogen sulfide and FT(rM-0.1904. pE0.05) as well as the VAS and FT (rM-0.210. pE0.05). S0, it was estimated that the less oral malador was recognized when caries state changed to filled state in Hydrogen sulfide laboratory test or VAS test 2. High relationship was showed between salivary flow and Hydrogen sulfide (rM-0.183, pM0.039), Methyl mercaptan(rM-0.234, p-0.008). Dimethyl sulfide(rM-0.234, pM0.008) and Ammonia(-0.361. pM0.001) gas(pE0.05). 3. There was a high relationship between M-PHP(Modified-Patient Hygiene Performance Index) and tong plaque all kinds of sulfide(rM0.249. pM0.005). Ammonia gas component(rM0.232, pM0.009). 4. It was found that considerable relationship was appeared between the periodontal status and Ammonia gas (rM0.274, pM0.002), so, it should be needed to control Ammonia. Such dental Cares as the prevention or early treatment of periodontal disease and the accelerating the salivary flow as well as reducing the amounts and activities of filament or spiral typed oral micro-organism were recommended for adults, not only for dental care program at the dental clinics but also for public health programs, in order to promote the oral health and quality of file for individual and community peoples.

• Applied Biological Chemistry
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• v.28 no.4
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• pp.219-225
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• 1985

The viscometric properties of six kinds of waxy starches of Olchal and Hankang(waxy rice), Chalborie (waxy barley), Yullmoo (waxy Job's tears), Chajoe (waxy foxtail millet), Chalsusu (waxy great millet) and Chalocsusu (waxy corn) were investigated. The increase in optical transmittance of 0.1% starch suspensions occurred at $55^{\circ}C$ for Hankang, $60^{\circ}C$ for Olchal, Chalborie, Chajoe and Yullmoo and $65^{\circ}C$ for Chalsusu and Chalocsusu, and further inrreased $70^{\circ}C$ for Hankang and Olchal, $75^{\circ}C$ for Chajoe, Chalsusu, Chalocsusu and Yullmoo and above $85^{\circ}C$ for chalborie. Amylogram on 5%, starch suspensions showed that gelatinization temperature and maximum peak height were 850 B.U. at $62^{\circ}C$ for Hankang, $65^{\circ}C$ and 980 B.U. for Olchae, $64^{\circ}C$ and 1,080 B.U. for Chalborie, and 1,410 B.U. at $69^{\circ}C$ for Yullmoo, and 1,280 B.U. at $71^{\circ}C$ for Chajoe, and 1,260 B.U. at $71^{\circ}C$for Chalsusu and 1,420 B.U. at $70^{\circ}C$ for Chalocsusu. Swelling power of starches was $38{\sim}55$, and Hankang, Olchal, Chajoe, Chalocsusu and Yullmoo starches had higher swelling power than Chalsusu and Chalborie starches. Intrinsic viscosity of them was $1.43{\sim}1.75$ and hardness of them highly relevant to the gelatinization properties.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.4
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• pp.497-504
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• 2008

This study was conducted for the optimization of ingredients in salad dressing using Bokbunja (Rubus coreanum Miquel) juice. The experiment was designed according to the D-optimal design of mixture design, which included 14 experimental points with 4 replicates for three independent variables (Bokbunja juice $15.70\sim47.10%$, oil $23.50\sim39.20%$, vinegar $3.90\sim19.60%$). The compositional and functional properties of the prepared products were measured, and these values were applied to the mathematical models. A canonical form and trace plot showed the influence of each variable on the quality attribute of final mixture product. By the use of F-test, viscosity, color values (L, a, and b), emulsion stability and sensory characteristics (color) were expressed by a linear model, while the color values (L) and sensory characteristics (smell, taste, and overall acceptance) were by a quadratic model. The optimum formulations by numerical and graphical method were analogous: Bokbunja juice, oil and vinegar of 36.02%, 26.48%, and 12.00% by numerical method, respectively; those of 36.00%, 26.44%, and 12.06% by graphical method, respectively.

• The Journal of Engineering Research
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• v.5 no.1
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• pp.73-87
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• 2004

The synthesis and crystallization of amorphous calcium carbonate($CaCO_3$.$nH_2 O$) obtained from gas-liquid reaction between aqueous solution of calcium hydroxide and carbon dioxide at 15~$50^{\circ}C$ are investigated by electrical conductometry, XRD and TEM. The results are as follows: The initial reaction products prior to the formation of precipitated calcium carbonate is amorphous calcium carbonate. The electrical conductivity values in the slurry are decreased during the formation of amorphous calcium carbonate which covers particle surface of calcium hydroxide and retard the dissolution of calcium hydroxide into the solution. that amorphous calcium carbonate is unstable in the aqueous solution and crystallizes finally to calcite by the through-solution reaction. While amorphous calcium carbonate crystallizes into chain-like calcite, the conductivity values are recovered rapidly and the apparent viscosity of slurry containing higher concentration of calcium hydroxide increase. At below pH 9.5, chain-like calcite separates into individual particles to form precipitated calcium carbonate. The formation and synthetic temperature range of amorphous calcium carbonate is most suitable a primary decreasing step(a-step) at $15^{\circ}C$ in the electrical conductometry.

• Korean Journal of Poultry Science
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• v.16 no.3
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• pp.157-167
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• 1989

Pretreatment of egg white and ion exchange resins was attempted to separate lysozyme from egg white efficiently. Apparent viscosity of egg white could be decreased to 3cp by homogenization for 30 minutes at 2, 000rpm and ultrasonication for 45 minutes. The result of testing adsorption capacity of lysozyme was as follows； CM-Sephadex C-25 ＞Duolite C464＞Amberlite C-50＞Dowex MSC-1＞Amberlite IRC-50＞Amberlite IRC-84. Although CM-Sephadex C-25 showed highest adsorption capacity of lysozyme, egg white could not eluted easily. Duolite Cf64 was selected based on relatively high lysozyme adsorption and good egg white eluting property for separation of egg white lysozyme. Na$^{＋}$ form of Duolite C-464 was most effective on adsorption of Iysozyme. To separate lysozyme from egg white efficiently rinse buffer and eluting solution were selected 0.1M sodium phosphate buffer at pH 6.5 and 10% ammonium sulfate respectively. After separating lysozyme from egg white, foaming power of egg white was decreased to 85.3%. Color of egg white gel was not changed while hardness of egg white gel was decreased by 30% after separating lysozyme. However, elasticity of egg white gel was increased by 13% in lysozyme-separated egg white.

• Proceedings of the Korean Society of Rheology Conference
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• 2006.06a
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• pp.81-84
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• 2006

Slot coating process, in continuous and patch modes, has been applied for the many precise coating products, e.g., flat panel displays and second batteries. However, manufacturing uniform coating products is not a trivial task at high-speed operations because various flow instabilities or defects such as leaking, bubbles, ribbing, and rivulets are frequently observed in this process. It is no wonder, therefore, that many efforts to understand the various aspects of dynamics and coating windows of this process have been made both in academia and industry. In this study, as the first topic, flow dynamics within the coating bead in slot coating process has been investigated using the one-dimensional viscocapillary model by lubrication approximation and two-dimensional model by Flow-3D software. Especially, operability windows in both 1D and 2D cases with various slot die lip designs have been successfully portrayed. Also, effects of process conditions like viscosity and coating gap size on slot coating window have been analyzed. Also, some experiments to find minimum coating thickness and coating windows have been conducted using slot die coater implemented with flow visualization device, corroborating the numerical results. As the second topic, flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process, which is employed in manufacturing IT products such as secondary batteries, has been investigated for the purpose of optimal process designs. As a matter of fact, the flow control in this system is more difficult than in continuous case because od its transient or time-dependent nature. The internal die and die lip designs for patterned uniform coating products have been obtained by controlling flow behaviors of coating liquids issuing from slot. Numerical simulations have been performed using Fluent and Flow-3D packages. Flow behavior and pressure distribution inside the slot die has been compared with various die internal shapes and geometries. In the coating bead region, efforts to reduce irregular coating defects in head and tail parts of one patterned coating unit have been tried by changing die lip shapes. It has been concluded that optimal die internal design gas been developed, guaranteeing uniform velocity distribution of both Newtonian and shear thinning fluids at the die exit. And also optimal die lip design has been established, providing the longer uniform coating layer thickness within one coating unit.

• Journal of the Korean Wood Science and Technology
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• v.37 no.6
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• pp.537-545
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• 2009

The objective of this study was to investigate potential usage of environmentally friendly building materials, liquid mortar and dry cement mortar mixed with charcoal, based on the test of their physical and chemical properties. From the test results of physical and chemical properties of the liquid mortar mixed with charcoal, liquid mortar containing over 20% of charcoal, the consistency viscosity and the non-volatile content met a standard requirement. Drying time was delayed with increase in charcoal contents in the liquid mortar, however they were fully cured within 60 minutes in all treated levels. Other properties were acceptable at standard requirement. From the results, it was found that the proper charcoal addition level to the liquid mortar was 25%. In the results on dry cement, it was found that samples containing 5% of charcoal showed the maximum compressive strength, whereas samples containing over 20% of charcoal did not reach the minimum requirement of KS standard. Water retention ability constantly increased as the charcoal ratio increased. The conventional dry cement mortar adsorbed 59.5% of it, in the test of adsorption rate on ammonia gas, whereas cement mortar containing 10% of charcoal showed 71.6% of ammonia gas adsorption.

• Journal of Veterinary Clinics
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• v.24 no.2
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• pp.182-191
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• 2007

Bioabsorbable devices have been utilized and experimented in many aspects of orthopaedic surgery. Depending upon their constituent polymers, these materials can be tailored to provide sufficient rigidity to allow bone healing, retain mechanical strength for certain period of time, and then eventually begin to undergo degradation. The objective of this study was to estimate extent in which Poly-L-latic acid (PLLA) implants had bioabsorbability and biocompatibility with bone and soft tissue in dogs and also to develop bioabsorbable, biocompatible materials with the appropriate strength and degradation characteristics to allow for regular clinical use for treating orthopedic problems in humans as well as animals. Eighteen dogs were used as experimental animals and were inserted two types of PLLA implants. PLLA rods were inserted into subcutaneous tissue of back or the abdomen wall. And the rods were tested for material properties including viscosity, molecular weight, melting point, melting temperature, crystallinity, flexural strength, and flexural modulus over time. PLLA screws were inserted through cortical bone into bone marrow in the femur of the dogs and stainless steel screw was inserted in the same femur. Radiographs were taken after surgery to observe locations of screw. Histological variations including cortical bone response, muscular response, bone marrow response were analyzed over the time for 62weeks. The physical properties of PLLA rods had delicate balances between mechanical, thermal and viscoelastic factors. PLLA screws did not induce any harmful effects and clinical complications on bone and soft tissue for degradation period. These results suggest that PLLA implants could be suitable for clinical use.

• Korean Journal of Microbiology
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• v.53 no.2
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• pp.103-117
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• 2017

The aim of this study was to evaluate the effect of green tea extract on probiotic potential, physico-chemical and functional properties of yogurt fermented with Lactobacillus acidophilus D11 or Lactobacillus fermentum D37 strains isolated from Doenjang. Probiotic activities such as the resistance to artificial digestive juices and the ability to adhere to epithelial cells were slightly higher in yogurt supplemented with green tea extract than in plain yogurt, which may be attributed to the increase in the number of lactic acid bacteria (LAB) by green tea extract supplementation. Furthermore, the microbiological and physico-chemical properties such as the number of LAB, organic acid production and viscosity were significantly (P<0.05) increased in yogurt added green tea extract compared to plain yogurt fermented with L. acidophilus D11. However, the green tea extract did not significantly (P>0.05) affect these properties of yogurt fermented with L. fermentum D37 strain. Meanwhile, the antibacterial activities against Escherichia coli O157 ATCC 43889, Salmonella enteritidis ATCC 13076, and Salmonella typhimurium KCTC 2514 and antioxidant activities including total phenol content, radical scavenging ability, and ferric-reducing antioxidant power were significantly higher in plain yogurt fermented with L. fermentum D37 than with L. acidophilus D11. The antibacterial and antioxidant activities of the yogurt were significantly (P<0.05) increased in proportion to the concentration of green tea extract added to plain yogurt. Consequently, green tea yogurt fermented with L. acidophilus D11 or L. fermentum D37 was considered to be a useful functional food that can inhibit the growth of pathogenic bacteria and scavenge the free radicals from the body cells.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.3
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• pp.17-27
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• 2009

Purpose: This review article was written to determine the effects of parameters characterizing a hard contact lens (RGP included), such as BCs, diameters, edge angles, on the time interval for tight fitted lens to return to the equilibrium when it was decentered from blinking. Methods: A mathematical formulation was established to relate or calculate the restoring forces and thickness of lacrimal layer beneath the cornea with the various lens parameters when the tight fitted lens was decentered from blinking. Based on this formulation the differential equations and their numerical solution program were set up to describe the time dependence of the lens on the position and to estimate the time for the lens's return to the equilibrium after blink. Results: It is found that the time interval for the tight fitted lens to return to the equilibrium decreases as either the BC decreases or the diameter increases because both the reduction in BC and increase in diameter result in the increase in the lacrimal layer thickness between the lens and cornea increase which yielded the lowering of the viscous friction in the lens motion. As the edge angle of tight fitted lens increases the time for recentering decreases due to the increase in restoring force without change in lacrimal thickness beneath the lens. In the case of flat fitted hard lens (RGP included), the lacrimal layer thickness under the lens increases as either BC or diameter increases which results in reduction in viscous friction so that the time for the lens's return to the equilibrium were to decrease. The edge angle of flat fitted lens does not affect the lens motion. Conclusions: The effect of BCs on the lens motion (time to approach the equilibrium) was concluded to be significant with both tight and flat fitted lens where its results are contrary with each other. The edge angle of lens only affects the motion in tight fitted lenses.