• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.1
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• pp.301-312
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• 1997

The purpose of this study was to evaluate the analgesic effect on pulp induced by pulsed Nd : YAG laser according to the power density, irradiated time and the method of application (Non-contact vs contact) in vivo. Experiments were carried out on 90 volunteers who have sound 4 canines. Each canine was grouped by the intensity and the time of irradiation of pulsed Nd : YAG laser was measured. Mean EPT response(units) was measured at 5 min, 30 min, and 60 min after irradiation with various intensity(1.5-3W, 15-30Hz), irradiated time (1.5min, 3min), and application method (Non-contact and contact). The results were as follows: 1. 5 minutes after irradiation, the mean EPT response(units) was increased by 32 % in the non-contact method and by 35% in the contact method of application. Which showed significant difference in mean EPT response(units) compared to not-lased canine in each groups(P<0.05). 2. The mean EPT response(units) with irradiating condition according to the various laser intensity, and the irradiation time stastically did not show significant difference in each groups as time elapsed. 3. There was no significant difference between the non-contact and contact method in the mean EPT response(units). 4. The mean EPT response(units) returned to the baseline value within 30 miuntes. In regard to the above results, the analgesic effect on pulp induced by pulsed Nd : YAG laser resulted a slight increase of pulpal pain threshold, but it was not as high as to replace the role of drug analgesia as whole. This technique can be used for inducing pulpal analgesia as adjunct to other pain control methods and is needed to develop better analgesic effects.

• 한국노년학
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• v.38 no.3
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• pp.409-433
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• 2018

The purpose of this study is to examine the effect of contact with the elderly in a daily life on children's ageist attitude. Acknowledging the people's tendency to report in socially appropriate ways to the explicit attitude measurement, implicit measurement is introduced, and relation with the daily contact with elderly(DCE) is analyzed. The research question are as follows: 1) Are these two attitudes explained by different factors? 2) Can DCE alleviate both children's implicit and explicit ageist attitude? 3) How do the contact with grandparent and neighboring elderly affect the children's explicit and implicit ageist attitude? Data was collected from 503 fourth to sixth grade elementary school children. Child-Age Implict Association Test is used to measure implicit ageist attitude. Multinominal logistic analysis and ordered logistic analysis was applied. Followings are the main results: First, explicit and implicit ageist attitudes are found to be related with different predictors. Second, Elderly contact seems to lighten children's ageist attitude overall. Third, the effects of grandparental contact and the neighboring elderly contact on two different ageism were different. While the effect of elderly neighbor contact is limited to the expression of ageism, grandparental contact has a influence not only on the explicit but also on the implicit ageism, even though the effect on implicit attitude is limited in extent. Forth, not the quality of contact but the quantity of it was related to implicit ageist attitude. This result contradicts conventional idea of Intergroup Contact Theory. In the further research, the predictor of implicit ageist attitude need to be throughly examined.

• Korean Journal of Materials Research
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• v.26 no.8
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• pp.412-416
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• 2016

The electrical properties of Au/n-type Ge Schottky contacts with different contact areas were investigated using current-voltage (I-V) measurements. Analyses of the reverse bias current characteristics showed that the Poole-Frenkel effect became strong with decreasing contact area. The contribution of the perimeter current density to the total current density was found to increase with increasing reverse bias voltage. Fitting of the forward bias I-V characteristics by considering various transport models revealed that the tunneling current is dominant in the low forward bias region. The contributions of both the thermionic emission (TE) and the generation-recombination (GR) currents to the total current were similar regardless of the contact area, indicating that these currents mainly flow through the bulk region. In contrast, the contribution of the tunneling current to the total current increased with decreasing contact area. The largest $E_{00}$ value (related to tunneling probability) for the smallest contact area was associated with higher tunneling effect.

• Korean Journal of Materials Research
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• v.13 no.5
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• pp.313-316
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• 2003

The new epitaxial base cell as a high efficiency Si solar cell was fabricated and the effect of buried contact on the cell characteristics was investigated. In our experiments, the cell with buried contact showed the open circuit voltage of 0.62 V, the short circuit current of 40 mA, the fill factor of 0.7, and the efficiency of 10% under the incident light of AM-1 100 ㎽/$\textrm{cm}^2$. The insertion of buried contact in the epitaxial base structure brought the fabricated cell to the efficiency improvement of about 33%. The cell proposed in this paper has the structural superiority in the fabrication of high efficiency solar cell due to the carrier drift transport in the optical absorption region and the formation of back surface field by $p^{－}$ $p^{+}$ epitaxial base, and the reduction of emitter series resistance by n＋ buried contact.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.29 no.4
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• pp.78-94
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• 2016

Objectives : This study was carried out to analyze the trends of clinical studies of allergic contact dermatitis published in the Journal of Korean Medical Ophthalmology & Otolaryngology & Dermatology. Methods : We studied 10 research papers on allergic contact dermatitis published in JKOOD. We analyzed about experiment methods, pharmacodynamic effects, therapeutic effects in published papers. Results : 1. The number of searched journal is 10 papers. 2. All experiments was performed using DNCB primed mouse. To demonstrate therapeutic effect of drugs, previous researches observed dermatological and histopathogical conditions, erythema, melasma, white blood cell count, Lymphocyte ratio to white blood cell. 3. Most of drugs have heat-clearing and detoxifying effects. 4. Every drugs have positive effect in treating allergic contact dermatitis. Conclusions : Figuring out how experiment proceeded and tendency of drugs in researching allergic contact dermatitis is significance of this paper. Further research about drugs and their treating methods should be carried out to improve curative effectiveness for allergic contact dermatitis.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.1
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• pp.55-58
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• 2001

The rigid gas permeable(RGP) contact lens has nearly side effect on the cornea. So that, this lens has used the clinical reflective correction of the eye. This study have used several methods for research the fine internal structure on the RGP contact lens by scanning electron microscopy. The results have indicated that the postfixation of 1% $OsO_4$ and tannic acid is responsible for a fine structure in the internal plane of RGP contact lens. These internal surface of contact lens appeared the several shape of the hole of the stereo shape form with arrangement of round form. But, on the contact lens with non-postfixation, the stereo shape have not present and the boundary of the vesicle have not clear. Maybe, these results suggest that the fixation methods have effect on the morphological characters of materials on the RGP contact lens.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.3
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• pp.52-56
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• 2011

Active regeneration in CDPF requires $O_2$ which regenerates soot at high temperature. However, small amount of NO can interrupt $O_2$ regeneration in CDPF. To verify this phenomena, soot oxidation experiments using a flow reactor with a $Pr/CeO_2$ catalyst are carried out to simulate Catalyzed Diesel Particulate Filter (CDPF) phenomena. Catalytic soot oxidation with and without small amount of NO is conducted under tight contact condition. As the heating rate rises, the temperature gap of maximum reaction rate is increased between with and without 50ppm NO. To accelerate the $NO_2$ de-coupling effect, CTO process is performed to eliminate interfacial contact for that time. As CTO process is extended, temperature which indicates peak reaction rate increases. From this result, it is found that small amount of NO can affect tight contact soot oxidation by removal of interfacial contact between soot and catalyst.

• Korean Journal of Materials Research
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• v.24 no.3
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• pp.140-144
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• 2014

The contact mechanism of devices is usually researched at electrode contacts. However, the contact between a dielectric and channel at the MOS structure is more important. The graphene was used as a channel material, and the thin film transistor with MOS structure was prepared to observe the contact mechanism. The graphene was obtained on Cu foil by the thermal decomposition method with $H_2$ and $CH_4$ mixed gases at an ambient annealing temperature of $1000^{\circ}C$ during the deposition for 30 min, and was then transferred onto a $SiO_2/Si$ substrate. The graphene was doped in a nitrogen acidic solution. The chemical properties of graphene were investigated to research the effect of nitric atoms doping. The sheet resistance of graphene decreased after nitrogen acidic doping, and the sheet resistance decreased with an increase in the doping times because of the increment of negative charge carriers. The nitric-atom-doped graphene showed the Ohmic contact at the curve of the drain current and drain voltage, in spite of the Schottky contact of grapnene without doping.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.9
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• pp.822-829
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• 2002

This paper deals with the distribution characteristics of the current density and axial magnetic flux density for each slits made on the contact electrode in the vacuum interrupter with axial magnetic field type using 3-dimension finite element analysis. It has been known that the presence of an axial magnetic field parallel to the current flow in the arc plasma can increase the high current breaking capacity of vacuum interrupter by carrying out the arc plasma from constricted mode to diffusion mode. The axial magnetic field is created of itself by current flow in the segments of coil electrode behind the contact electrode. The analyzed results show that if the slits are made in the contact electrode, they can increase the current density and axial magnetic flux density in the contact electrode surface and at the gap distance, which is due to decrease the effect of eddy currents flowing in the contact electrode. The phase shift due to eddy currents, defined 3s time difference between the maximum value of current and axial magnetic field, is decreased still more by increasing the number of slits made in the contact electrode at the center point of gap distance. These results demonstrate that 3-dimension finite element analysis has a great deal of merits in the development and evaluation of new electrode at the design of vacuum interrupter.

• Tribology and Lubricants
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• v.10 no.4
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• pp.75-81
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• 1994

In load sharing model, the load is supported by the contacting asperities and the lubricants. The asperity contact area of two sliding surfaces are relatively very small as compared with the apparent contact area. The asperity contact pressure is relatively higher than the lubricant pressure. With the combined effect of asperity and lubricant pressure, the surface roughness and temperature rise must be considered to calculate the lubricant film thickness of the line-contact bearing.