• 공업화학
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• 제8권4호
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• pp.595-601
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• 1997

철 환원법에 의한 엣칭용 염화철 폐액의 처리에서 니켈이 부착된 미반응 철분을 재생하기 위해서 볼밀 및 초음파 처리를 사용하였다. 철분을 2회 재생하였을 때 니켈 제거 효율은 볼밀을 2시간 처리한 경우와 초음파를 4시간 처리한 경우 각각 94.0%와 82.1%이었다. 재생 처리하지 않고 철분을 3회 사용하였을 때 니켈 제거 효율은 40.0%이었다. 처리시간이 증가함에 따라 볼밀처리에서는 철분의 크기가 감소하였으나, 초음파 처리에서는 철분의 크기 변화가 거의 없었다.

• 한국치위생학회지
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• 제14권3호
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• pp.439-446
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• 2014

Objectives : The purpose of the study is to investigate the correlation between the pain, depression, dental anxiety in the patients visiting to dental clinic for the ultrasonic scaling treatment. Methods : The study is a cross-sectional correlation study. A self-reported questionnaire was filled out by 254 patients having no history of mental illness in Seoul and Gyeonggido from December 12 to 20, 2013. The study instruments included modified Beck's Depression Inventory (BDI), STAI items by Spilberger, Humphis' Modified Dental Anxiety Survey(MDAS), and Visual Analogue Scale. Results : There existed correlation between the ultrasonic scaling pain, depression, dental anxiety, trait anxiety, and state anxiety. Dental anxiety was the most influencing factors on the pain. Conclusions : It is very important to reduce the anxiety in the patients more actively.

• Transactions on Electrical and Electronic Materials
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• 제14권5호
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• pp.268-272
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• 2013

The aim of this study was to develop an ultrasonic tooth-whitening apparatus using piezoelectric transducers, which enhance bleaching efficiency by applying ultrasound, while performing a teeth whitening procedure. For this purpose, an ultrasonic transducer was designed and manufactured, and the effects of reduction in the whitening material's concentration and in the whitening treatment time through using the ultrasound cavitation phenomenon were confirmed. Also, the validity of this study was investigated by comparing the whitening performance with a commercialized optical whitener, through color comparison. The results revealed that the ultrasound whitener produced color values that were enhanced by as much as double that of the conventional LED light whitening method. Even when the operational time was reduced by half, the ultrasound method showed superior performance by over 54% compared to the conventional light whitener, revealing that the ultrasound method showed a remarkable treatment reduction effect.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.121.1-121.1
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• 2014

Recently, much attention has been given to plasma production under liquid and its applications [1]. However, most of plasma production techniques reported so far utilize high voltage dc, ac, rf or microwave power [2], where damage to discharge electrodes and small discharge volume are remained issues. As an alternative of plasma production method under liquid, we have proposed pulsed microwave excited plasma using slot antenna, where damage to the slot electrode can be minimized and plasma volume can be increased. We have also reported improvement of treatment efficiency with use of reduced-pressure condition during the discharge [3]. To realize low pressure conditions in liquid, various alternative technique can be considered. One possible technique is simultaneous injection of microwave power and ultrasonic wave. Ultrasonic wave induces pressure fluctuation with the wave propagation and is so far used for cavitation production in the water. We propose utilization of reduced pressure induced by ultrasonic cavitation for improvement of the plasma production. Correlation between the plasma production and the ultrasonic power will be discussed.

• Tribology and Lubricants
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• 제19권5호
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• pp.285-291
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• 2003

Ultrasonic vibrator is an equipment which atomizes and homogenization the oils by breaking the oil particles with ultrasonic cavitation, and would improve the properties. The present study deal with the ultrasonic breaking systems which recycle the shipborne waste oil into usable oil to be burnt. The first place, experimental studies were carried out to investigate the homogenizing effect of the waste oils by ultrasonic cavitation. Variation of the properties(viscosity, specific gravity and pH) and the matrix structures for the various shipborne waste oils were interpreted to analyse the breaking, dispersion effects by ultrasonic cavitation. The experimental results can be useful to the development of waste oil disposing systems.

• 한국주조공학회지
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• 제9권3호
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• pp.228-236
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• 1989

The relationships between nodularity, tensile property and ultrasonic velocity were studied in ductile iron castings having similar matrix structure. Also, the effects of heat treatment and the number of graphite nodules on the ultrasonic velocity were investigated. The results were as follows 1. The ultrasonic velocity increased proportionally with increassing nodularity and tensile strength. 2. The ultrasonic velocity in annealed and normalized state decreased average 1.7% and 3.4% respectively than that in as cast state. 3. The ultrasonic velocity increased with increasing the number of graphite nodules. Therefore, ductile iron castings can be evaluated in the only case of castings having the same manufacturing history by ultrasonic velocity.

• 펄프종이기술
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• 제40권2호
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• pp.16-22
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• 2008

The pilot scale ultrasonic deinking was carried out in order to confirm the commercialization possibility of ultrasonic deinking. White ledger was used as a raw material and the results were compared to the results obtained from the conventional deinking. The fraction of smaller ink particle was increased and the improved ink removal efficiency was also obtained by the ultrasonic treatment. The brightness and breaking length of ultrasonic deinked pulp were superior to those of the conventional deinked pulp. Most interesting findings in this study were that the significant improvement in effluent quality and the reduction of chemicals and energy cost were obtained by the ultrasonic deinking.

• 한국환경과학회지
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• 제26권4호
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• pp.421-432
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• 2017

In this study, we examined the suitability of ten disinfection models for predicting the inactivation of Artemia sp. via single or combined physical and chemical treatments. The effect of Hydraulic Retention Time (HRT) on the inactivation of Artemia sp. was examined experimentally. Disinfection models were fitted to the experimental data by using the GInaFiT plug-in for Microsoft Excel. The inactivation model were evaluated on the basis of RMSE (Root Mean Square Error), SSE (mean Sum Square Error) and $r^2$. An inactivation model with the lowest RMSE, SSE and $r^2$ close to 1 was considered the best. The Weibull+Tail model was found to be the most appropriate for predicting the inactivation of Artemia sp. via electrolytic treatment and electrolytic-ultrasonic combined treatment. The Log-linear+Tail model was the most appropriate for modeling inactivation via homogenization and combined electrolytic-homogenization treatment. The double Weibull disinfection model was the most suitable for the predicting inactivation via ultrasonic treatment.

• Journal of Periodontal and Implant Science
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• 제27권1호
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• pp.205-215
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• 1997

In periodontal regeneration treatment, access to the frucation area is very difficult. Thus complete removal of plaque, calculus and endotoxin is somewhat impossible. In this study, teeth that were extracted due to periodontal disease were used. The furcation area was treated with periodontal curette, ultrasonic scaler, roto bur and they observed using SEM. The result was follows 1. The group treatment with curette showed remaining plaque, the cementum existed in most of the surface and partial dentinal tubule orifice could be seen. 2. The group treatment with ultrasonic scaler showed less removalof plaque compared to curette and irregular surface could be seen. 3. The group treatment with roto bur showed cleaner surface and many dentinal tubule orifice could be seen compared to the curette and ultrasonic scaler groups. Thus when suing treatments such as bone grafting or guided tissue regeneration, it is considered that the furcation area should be treatment with Roto bur.

• Advances in environmental research
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• 제5권4호
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• pp.251-262
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• 2016

The biodegradability and decomposition efficiencies increase with the pre-treatment of sludge in a digestion process. In this study, the feasibility of ultrasound coupled with potassium permanganate oxidation as a disintegration method and digestibility of aerobic reactor fed with disintegrated sludge with ultrasound coupled potassium permanganate were investigated. The first stage of the study focused on determining the optimum condition for ultrasonic pre-treatment for achieving better destruction efficiency of sludge. The second part of the study, the aerobic digestibility of sludge disintegrated with ultrasound and potassium permanganate oxidation alone and combined were examined comparatively. The results showed that when 20 min of ultrasonic pre-treatment applied, the specific energy output was 49384 kJ/kgTS with disintegration degree of 58.84%. During the operation of aerobic digester, VS/TS ratios of digesters fed with disintegrated sludge decreased indicating that disintegration methods could obviously enhance aerobic digestion performance. The highest reduction in volatile solids was 75% in the digester fed with ultrasound+potassium permanganate disintegrated sludge at the end of the operation compared to digester fed with raw sludge. Total Nitrogen (TN) and Total Phosphorus (TP) levels in sludge supernatant increased with this combined method significantly. Besides, it promoted the production of ${\bullet}OH$, thus enhancing the release of Carbon (C), Nitrogen (N) and Phosphorus (P) from the sludge. Disintegration with all methods used in this study could not improve Capillary Suction Time (CST) reduction in disintegrated digesters during the operation. The results demonstrated that the combined ultrasound treatment and potassium permanganate oxidation method improves the biodegradability compared to control reactor or their single application.