• Journal of Korean Ophthalmic Optics Society
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• v.19 no.1
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• pp.23-30
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• 2014

Purpose: The present study was aimed to figure out the correlation amongst the evaluation methods for critical micelle concentration, surface tension and protein cleaning efficacy to evaluate cleaning efficacy of contact lens care products. Methods: The critical micelle concentration of surfactants and the actual concentration of surfactants in contact lens care solutions were investigated by employing references published and related information. Surface tension of contact lens care solutions was measured by surface tension device at $25{\pm}1^{\circ}C$, and contact lenses made of lotrafilcon A, comfilcon A and balafilcon A were washed with contact lens care solutions after the incubation in artificial tears for 14 days and their cleaning efficacy was compared. Results: Among the 22 contact lens care products, 9 products provided the label of the concentration of surfactant, and 7 products showed higher concentration of surfactant than the critical micelle concentration reported in references. As a result of measuring surface tension, the surface tension of lens care products for soft contact lens was generally lower than other care products. When examined the removal effect of protein deposited on lens surface, it was known that the care products having lower surface tension showed higher protein removal efficiency. Conclusions: The surface tension is low when surfactant concentration in contact lens care solutions is high, and the removal effect of protein deposited is accordingly increased with the decrease of surface tension. Thus, these indicate the correlation amongst the evaluation methods for cleaning efficacy.

• Journal of Power System Engineering
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• v.15 no.1
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• pp.24-31
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• 2011

Rectangular box type structures are used in many fields of civil, mechanical and marine engineering. Especially, Most ship structures are often in contact with inner or outer fluid, like ballast, fuel and stem tanks. Fatigue damages are sometimes observed in these tanks which seem to be caused by resonance with exciting force of engine and propeller. Vibration characteristics of these thin walled tanks in contact with fluid near engine and propeller are strongly affected by added mass of containing fluid. Therefore it is essentially important to estimate the added mass effect to predict vibration of the tanks. Many authors have studied vibration of rectangular tanks containing fluid. Few research on dynamic interaction among tank walls filled with fluid are reported in the vibration of rectangular tanks recently. In case of rectangular tanks, structural coupling between adjacent panels and effect of vibration modes of multiple panels on added mass of water have to be considered. In the previous report, a numerical analysis is performed for the coupling effect between panels of a tank on added mass of containing fluid, the effect of structural constraint between panels on each vibration mode for fluid region, and mode characteristics in accordance with changing breadth of the plates by using finite element method for plates and boundary element method for fluid region. In this paper, the coupling effect between panels of a tank on added mass of containing fluid, the effect of structural constraint between panels on each vibration mode for fluid region, and mode characteristics in accordance with changing length, thickness, and boundary condition of the plates are investigated numerically and discussed.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.5
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• pp.10-19
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• 1998

The erosion of electrode in spot welding of aluminium alloy by direct current is dependent on the electric polarity. The positive electrode is much more eroded than the negative one. To explain this phenomenon, Peltier effect has been generally accepted as a unique theory. In this study Peltier effect was evaluated by calculations on the basis of some references and experiments. The difference of heat generated by Peltier effect on both electrode surfaces was, however, only 4% of total heat generated during wel- ding. Because of insufficient explanation, Kohler theory, which is mainly affected by thin oxide film, was introduced. A theoretical calculation showed 17% of the temperature difference between the positive and negative electrode, in case "surface voltage" resulted from oxide film was 30% of total contact voltage. This revealed that the erosion of electrode could be more affected by Kohler theory than effect.an effect.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.428-433
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• 2003

We measured the effect of wettability of six MPSs for RGP(rigid gas permeable) lens. The used MPSs(multipurpose solutions) were OPTI-SOAK(ALCON), SOLO care hard(CIBA Vision), Total care(ALLERGAN), Simplicity(BOSTON), Wetting and Soaking Sol.(Bausch & Lomb) and Aquas-multi(Saehan). These MPSs keeps hydrophilic property of lens surface and increase the effect of cleaning or increase the effect of preservative effect. To compare with the effect of wettability we followed the way of contact angle measurement which was general way to measure wettability and compared lens which was conducted by each MPS made by different companies. As a control, 0.9% NaCl solution and artificial tears were used. The degree of the effect of wettability was decided by contact angle. It is hydrophilic property nearby $0^{\circ}$ of contact angle and it is closed by hydrophobic property as it increases. The results showed that every lens was nearby hydrophilic property within $25\;^{\circ}-36\;^{\circ}$. Also, it was differed by various factors. The surface tension showed various differences between 19.8 and 31.3 mN/m. In the viscosity, MPSs represented the highest viscosity between $4^{\circ}C$ and $20^{\circ}C$. It was much higher than compared with the viscosity of soft lens MPS. This experiment could be used to grasping the interaction between solutions used to MPS and the natural endowments of lens and to considering the relations of different factors effecting the wettability.

• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.81-98
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• 2003

The purpose of this study is to closely examine kinematic characteristics by jump phase of Li Xiaopeng motion in horse vaulting and provide the training data. In doing so, as a result of analyzing kinematic variables through 3-dimensional cinematographic using the high-speed video camera to Li Xiaopeng motion first performed at the men's vault competition at the 14th Busan Asian Games, the following conclusion was obtained. 1. It was indicated that at the post-flight, the increase of flight time and height and twisting rotational velocity has a decisive effect on the increase of twist displacement. And Li Xiaopeng motion showed longer flight time and higher flight height than Ropez motion with the same twist displacement of entire movement. Also the rotational displacement of the trunk at peak of COG was much short of $360^{\circ}$(one rotation) but twist displacement showed $606^{\circ}$. Likewise, Li Xiaopeng motion was indicated to concentrate on twist movement in the early flight. 2. It was indicated that at the landing, Li Xiaopeng motion gets the hip to move back, the trunk to stand up and the horizontal velocity of COG to slow down. This is thought to be the performance of sufficient landing, resulting from large security of rotational displacement of airborne and twist displacement. 3. It was indicated that at the board contact, Li Xiaopeng motion made a rapid rotation uprighting the trunk to recover slowing velocity caused by jumping with the horse in the back, and has already twisted the trunk nearly close to $40^{\circ}$ at board contact. Under the premise that elasticity is generated without the change of the feet contacting the board, it will give an aid to the rotation and twist of pre-flight. Thus, in the round-oH phase, the tap of waist according to the fraction and extension of hip joint and arm push is thought to be very important. 4. It was indicated that at the pre-flight, Li Xiaopeng motion showed bigger movement than the techniques of precedented studies rushing to the horse, and overcomes the concern of relatively low power of jump through the rapid rotation of the trunk. Li Xiaopeng motion secured much twist distance, increased rotational distance with the trunk bent forward, resulting in the effect of rushing to the horse. 5. At horse contact, Li Xiaopeng motion makes a short-time contact, and maintains horse take-off angle close to vertical, contributing to the increase of post-flight time and height. This is thought to be resulted from rapid move toward movement direction along with the rotational velocity of trunk rapidly earned prior to horse contact, and little shave of rotation axis according to twist motion because of effective twist in the same direction.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.5
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• pp.435-444
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• 2017

The vehicle-track structure dynamic interaction analysis problem can be treated as sliding contact problem, and it is assumed that vehicle run at a constant speed over a rail modeled as beam elements. Unfortunately, Salome-Meca can not satisfy the compatibility condition for the beam master elements, which are consist of the elements with higher order polynomial shape function, in sliding contact problem. In this study, it is suggested to use more finer beam master element mesh as the remedy for incompatibility in sliding contact problem, and the accuracy of the solution is secured. For this, the effect of beam element mesh refinement consisting runway is analysed through simple examples, and the applicability to the dynamic interaction analysis is evaluated. Finally, the dynamic interaction analysis of railway skewed culvert transition problem is carried out to evaluate the effect of supporting stiffness due to backfill pattern changes and track irregularity due to uneven subgrade settlement.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.26 no.4
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• pp.1-14
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• 2013

Objectives : The purpose of this study is to investigate effects of Syzygium aromaticum (SAE) spread on the allergic contact dermatitis caused by 2,4-dinitro-chlorobezene (DNCB). Methods : Forty-two mice were divided into six groups ; normal, negative control (DNCB-treated), positive control (DNCB + 1% pimecrolimus), experimental group I, II and III. control and experimental groups were induced allergic contact dermatitis by DNCB. Experimental group I(DNCB + 0.2% SAE), II(DNCB + 1% SAE) and III(DNCB + 5% SAE) were spread SAE and positive control was spread the 1% pimecrolimus. In this study, effect of SAE on clinical aspects on the skin, histopathological change, the blood level of IgE, cytokines, histamine were investigated. In addition, effect of SAE on spleen $CD4^+/CD8^+$ T cell subset was investigated. Results : 1. In experimental group I, II and III, erythemas and edema were more reduced than negative control. 2. In experimental group I, II and III inflammatory edema and the numbers of infiltrated inflammatory cells were more reduced than negative control. 3. In experimental group I, II and III, clinical skin score was more reduced than negative control. 4. In experimental group II and III, the thickness of skin was statistically significant reduced than negative control. 5. In experimental group II and III, histamine release was statistically significant reduced than negative control in dose-dependantly. 6. In experimental group II and III, cytokines (IL-1${\beta}$, TNF-${\alpha}$, IL-4, IL-6, IL-10) were statistically significant reduced than negative control in dose-dependantly. 7. In experimental group I, II and III, the level of total IgE was statistically significant reduced than negative control in dose-dependantly. 8. In experimental group III, $CD4^+$ and $CD8^+$ T cells were statistically significant decreased similar to the positive control. Conclusions : According to above experiments, Syzygium aromaticum(SAE) was effective on allergic contact dermatitis.

• Journal of Digital Convergence
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• v.18 no.1
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• pp.59-71
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• 2020

The purpose of this study was to examine the mediating effects of empathy in relation to contact experience of the elderly and their knowledge level of ageing. For this study data was collected from 20th Dec. to 30th of Dec. 2018 355 university students from D university in J. province were surveyed. Data was analysis by using reliability test, correlation analysis, hierarchical multiful regression analysis. The statistical significance of the mediating effects was confirmed by Sobel's verification. The results of the analysis showed that the partial mediation effect of empathy was verified with regard to the relationship between elderly contact experience and discrimination of elderly people. In addition, the partial mediation effect of empathy was verified between level of aging knowledge and the perception of elderly discrimination. The results of this study confirmed the necessity of developing practical education and training programs to improve the level of aging knowledge and to increase contact experience with elderly people. There is also a need to enhance empathy in order to improve the awareness of discrimination against elderly people in health and welfare departments among university students.

• The Korea Journal of Herbology
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• v.28 no.4
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• pp.77-81
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• 2013

Objectives : Horse oil (HO) has been used long time as the folk medicine of many Asian countries such as Korea, Mongol, China, India and Japan. HO has been used for anti-bacterial, anti-inflammatory, and anti-pruritic purposes in skin. However, it is still largely unknown whether HO modulates the skin condition. In this study, we attempted to evaluate the anti-inflammatory effect of HO on the 1 % of 2, 4-dinitro-1-chlorobenzene (DNCB)-induced contact hypersensitivity in Balb/c mice. Methods : To find the anti-inflammatory effect of HO, contact hypersensitivity, a local inflammatory response of skin, was induced on the back of Balb/c mice by sensitization and repeated application by 1% DNCB and HO treated 2 weeks on the 1% of DNCB-treated Balb/c mice. Excised mice skins were stained with hematoxylin and eosin and serum IgE level was measured by mouse IgE ELISA kit. Results : In this study, we found that HO reduced erythema by 1% of DNCB treated Balb/c mice. Also, HO recovered histopathological features such as the thickening of epidermis, hyperkeratosis and the infiltration of inflammatory cells in 1% of DNCB treated Balb/c mice. In addition, HO reduced IgE level on the serum obtained from blood of 1% of DNCB-treated Balb/c mice. Conclusion : Taken together, these results showed that HO could be used as a pharmaceutical material with anti-inflammatory effects by reducing of erythema, IgE level and recovering of histopathological features skin on DNCB-induced contact hypersensitivity in Balb/c mice model.

• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.264-271
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• 2015

Stink bugs do damage on various crops including upland crops and tree fruits. Especially, yellow-brown stink bug (Halyomorpha halys ($St{\aa}l$)) and brown-winged green (Plautia stali) are severely damaged on apple orchard. Using seven insecticides - dinotefuran WP, etofenprox WP, chlorpyrifos WP, cabaryl WP, chlothianidin SC, flonicamid WG, and bifenthrin WG - registered on apple, contact and residual toxicities were tested on both male and female of P. stali and H. halys that preferred apple fruit. Contact toxicity of dinotefuran WP was excellent on male P. stali 48 hours after treatment (HAT) with 96.7% and significant on male Halyomorpha halys 48 HAT with 74.5% but the others had low effect. Contact toxicity on these stink bugs were higher in male than female. All insecticides except flonicamid, residual effects were all effective on both male and female of P. stali, while chlorpyrifos and bifenthrin were showed higher residual toxicity on both male and female of H. halys in laboratory condition. Two insecticides, chlorpyrifos and bifenthrin, were selected for the field test. Bifenthrin have a high residual effect on P. stali until 5 days after treatment, but have a low residual toxicity on H. halys in the field test. Chlorpyrifos showed higher residual toxicity in the laboratory, however, showed low residual efficacy on two species stink bug onto the field.