초음파로 형성된 치근단 역충전와동의 정화도 및 와벽형태

김성교,이재환,백승무 大韓齒科保存學會 1997 Restorative Dentistry & Endodontics Vol.22 No.2

The purposes of this study were to evaluate the degree of cavity cleanliness and to observe cavity wall morphology when root-end retrograde cavity preparation was done with ultrasonics. Root resections were done on 20 extracted human maxillary central incisors after canal filling with gutta-percha, and retrocavities were prepared using a slow-speed round bur as a control, and stainless steel ultrasonic tips of power settings of 2 and 6(Miniendo^™, EIE, SA, USA) as experimentals. The degree of the remaining cavity debris and smear layer, and wall morphology were evaluated under the scanning electron microscope. The results were as follows: Cavity prepared with ultrasonics of either power setting showed significantly less smear layer than did slow-speed preparations(p<0.01). However, there was no significant difference in canal debris(p<0.05). Cavity prepared with ultrasonics showed hatcheted appearance of wall, while slow-speed preparation showed relatively plain one.

광섬유 Mach-Zehnder 간섭계를 이용한 부분방전 초음파 검출특성

이상훈,심승환,이광식,김달우 한국조명전기설비학회 2003 조명·전기설비학회논문지 Vol.17 No.4

It is well known that a partial-discharge(PD) in insulation oil is the source of various physical and chemical phenomena, such as heat, light, gas, chemical transformation, electric current, electromagnetic radiation and ultrasonics. The PD can be detected by measuring one of these changes. Although some techniques are employed in this purpose, several obstacles interfere with an on-line measurement. Ultrasonic-wave detection is a useful method for the diagnosis of the transformer-insulation condition. Conventionally, ulyrasonic waves are detected by Piezo-electric transducer, but we use optical method that has many advantages. In this paper, we constructed a Mach-Zehnder interferometer with optical fiber and investigated the principle of operation. Test arrangement is based on the needle-plane electrode system in oil and applied AC high voltage. Ultrasonic waves were detected and analyzed with wavelet transform. 본 논문에서는 유입변압기 진단을 목적으로 부분방전시 발생하는 여러 가지 물리적 화학적 현상중 초음파를 검출하기 위하여 광섬유 Mach-Zehnder 간섭계를 구성하였다. 구성된 광섬유 센서의 초음파 검출 평가 실험을 실시하고, 절연유 중에 배치한 침-평판전극에 교류 고전압을 인가하여 방전시 발생하는 초음파를 측정하고 퓨리에 변환 및 wavelet 변환을 이용한 데이터 분석 결과를 나타냈다.

최신 근관 세척 방법과 기구에 대한 고찰

유연지,신수정,백승호 大韓齒科保存學會 2011 Restorative Dentistry & Endodontics Vol.36 No.3

서론: 근관 치료의 성공을 위해 근관계 내에 남아있는 조직 잔사와 박테리아를 제거하는 것은 매우 중요하다. 그러나 충분한 근관 형성과 근관 세척을 하더라도 근관의 복잡한 형태로 인하여 근관 내 박테리아의 biofilm이나 괴사된 치수 조직이 남아 있게 된다. 근래 보다 효과적으로 근관 세척을 하기 위한 여러 가지 방법과 근관 세척을 위한 기구들이 개발되었다. 본 종설에서는 근관 치료 영역에서 사용되는 근관 세척 방법과 기구에 대해 고찰하고자 한다. 본론: 아래와 같은 기구와 방법이 논의된다. - syringe-needle irrigation, manual dynamic irrigation, brushes - sonic and ultrasonic irrigation, passive ultrasonic irrigation, rotary brush, RinsEndo, EndoVac, Laser 결론: 최근 근관 세척을 위한 기구와 세정 방법이 개발되었으나, syringe와 needle을 이용한 근관 세척법과 ultrasonic을 이용한 근관 세척법을 제외하고는 새로 개발된 많은 기구들의 임상적 치료 결과의 향상에 대한 근거 중심 연구가 아직은 부족하며, 어떠한 기구나 장치도 근관 내 잔사를 완벽하게 제거할 수는 없다. 효과적인 근관 세척을 위해서는 적절한 근관 세척제의 선택과 함께, 근관 세척제를 근관장까지 충분한 양이 도달할 수 있도록 적절한 근관 세척 기구와 방법을 선택하여야 한다. Introduction: Eliminating the residual debris and bacteria in the root canal system is one of the main purposes of the endodontic treatment. However, the complexity on the anatomy of the root canal system makes it difficult to eliminate the bacterial biofilm existing along the root canal surface and necrotic pulp tissue by mechanical instrumentation and chemical irrigation. Recently, more effective irrigant delivery systems for root canal irrigation have been developed. The purpose of this review was to present an overview of root canal irrigant delivery techniques and devices available in endodontics. Review: The contents of this paper include as follows; - syringe-needle irrigation, manual dynamic irrigation, brushes - sonic and ultrasonic irrigation, passive ultrasonic irrigation, rotary brush, RinsEndo, EndoVac, Laser Conclusion: Though technological advances during the last decade have brought to fruition new agitation devices that rely on various mechanisms, there are few evidence based study to correlate the clinical efficacy of these devices with improved outcomes except syringe irrigation with needle and ultrasonic irrigation. The clinicians should try their best efforts to deliver antimicrobial and tissue solvent solutions in predictable volumes safely to working length.

Tensile Property Evaluation of Additively Manufactured Ti–6Al–4V/Yttria-Stabilized Zirconia Composite Using Absolute Nonlinear Ultrasonic Technique

Seong-Hyun Park,Jiung Yoo,Gwanghyo Choi,Kyung-Young Jhang 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.4

Directed energy deposition (DED), which is used to fabricate 3D metal components layer-by-layer, is a form of additive manufacturing. Yttria-stabilized zirconia (YSZ), which is a ceramic reinforcement material, enhances several mechanical properties in DED. However, the nondestructive evaluation of YSZ during DED has not been reported so far. This paper proposes a tensile property evaluation technique of Ti–6Al–4V (Ti64)/YSZ composites manufactured by DED using absolute nonlinear ultrasonics. This is unique in the following aspects: (1) a tensile property evaluation technique was developed for Ti64/YSZ composites; (2) absolute measurement of nonlinear elastic coefficient in Ti64/YSZ was achieved using ultrasound; (3) the technique shows potential for nondestructive online monitoring. First, the strengthening mechanisms of Ti64/YSZ in DED were analyzed using tensile testing and metallography. Then, the changes in tensile properties with variations in the YSZ conditions were nondestructively assessed using the developed technique. The evaluation results are consistent with the destructive tensile testing results. Furthermore, the evaluation performance was superior to the conventional nondestructive testing.

Trimetallic FeAgPt alloy as a nanocatalyst for the reduction of 4-nitroaniline and decolorization of rhodamine B: A comparative study

Basavegowda, Nagaraj,Mishra, Kanchan,Lee, Yong Rok Elsevier 2017 Journal of alloys and compounds Vol.701 No.-

<P><B>Abstract</B></P> <P>Novel FeAgPt alloy nanoparticles were biosynthesized <I>via</I> ultra-sonication using the root extract of <I>Platycodon grandiflorum</I>. The nanoparticles exhibited enhanced catalytic activities in the reduction of 4-nitroaniline (4-NA) to <I>p</I>-phenylenediamine with a significantly reduced reaction time and increased rate constant because of their high number of active surface sites. In addition, the same catalyst exhibited enhanced catalytic activity in the decolorization of an environment polluting dye, rhodamine B (RhB). The time taken for the complete conversion of 4-NA to <I>p</I>-phenylenediamine was 25 min with an apparent rate constant of 10.06 × 10<SUP>−2</SUP> min<SUP>−1</SUP>. Similarly, the catalytic decolorization of RhB took 15 min for complete decolorization of the dye molecules with a rate constant 25.60 × 10<SUP>−2</SUP> min<SUP>−1</SUP>. The performance difference of mono, bi and trimetallic nanoparticles for both the reduction of 4-NA and decolorization of RhB was also examined. These trimetallic alloy nanostructures with excellent catalytic efficiency can also be used for other applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> FeAgPt alloy nanoparticles were prepared using a green method <I>via</I> ultrasonication. </LI> <LI> The synthesized nanoparticles were well characterized by XRD and TEM. </LI> <LI> The alloy nanoparticles showed the best catalytic reduction activity compared to mono and bimetallic nanoparticles. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Laser ultrasonic imaging and damage detection for a rotating structure

Park, Byeongjin,Sohn, Hoon,Yeum, Chul-Min,Truong, Thanh C SAGE Publications 2013 Structural health monitoring Vol.12 No.5

<P>This study presents a laser ultrasonic imaging and damage detection technique that creates images of ultrasonic waves propagating on a rotating structure and identifies damage. Laser ultrasonics is attractive for nondestructive testing mainly because of two reasons: (1) ultrasonic waves can be generated and/or measured in a noncontact manner and (2) even a small defect can be detected when laser ultrasonic scanning produces ultrasonic images with high spatial resolution. However, when it comes to a moving target, it becomes challenging to create reliable ultrasonic images. In this study, ultrasonic wave propagation images are obtained from a rotating blade using a pulse laser beam for ultrasonic generation, a galvanometer for laser scanning, and an embedded piezoelectric sensor for ultrasonic measurement. To properly estimate the laser excitation points during the scanning process rather than to precisely control the excitation points, a simple but rather effective localization technique is developed so that ultrasonic images can be constructed even from a moving target. Once the ultrasonic wave propagation images are created, damage on the target structure is visualized using a specially designed standing wave filter.</P>

초음파 세탁과 가정 세탁의 세척성과 직물변형 비교

황나원,정혜원,이광우 한국의류산업학회 2023 한국의류산업학회지 Vol.25 No.3

In this study, the efficacy of ultrasonic washing in cotton and wool fabrics was compared and evaluatedagainst conventional washing in terms of cleaning properties and fabric deformation. Factors such as washing tem-perature, time, liquid ratio, and detergent concentration were kept varied, and the cleaning properties of sebum-soiledfabrics were assessed using different detergents such as alcohol ethoxylate, linear alkylbenzenesulfonate, and IEC60456 Reference Detergent A*. In addition, the effects and emulsification power of enzymes and oxygen bleach wereexamined. To compare the cleaning properties with general washing, a launder-O-meter was used. To investigate fabricdeformation during the washing process, the loosening test cloth, shrinkage test cloth, and mechanical strength testcloth were compared between ultrasonic washing machines and household drum washing machines. The results indi-cate that ultrasonic washing exhibits superior cleaning properties than launder-O-meter when the temperature is lowand the washing time is short. Furthermore, there is less deformation and damage during the washing process. It wasalso observed that the activity of the detergent increases when ultrasonic waves are applied to the washing process. Considering the increasing tendency to pursue convenience and simplicity in clothing management as well as the antic-ipated commercialization of smart clothing with built-in electric circuits, ultrasonic laundry could serve as a new alter-native to existing laundry methods.

Ultrasonic Flaw Detection in Composite Materials Using SSP-MPSD Algorithm

BENAMMAR Abdessalem,DRAI Redouane 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.5

Due to the inherent inhomogeneous and anisotropy nature of the composite materials, the detection of internal defects in these materials with non-destructive techniques is an important requirement both for quality checks during the production phase and in service inspection during maintenance operations. The estimation of the time-of-arrival (TOA) and/or time-of-flight (TOF) of the ultrasonic echoes is essential in ultrasonic non-destructive testing (NDT). In this paper, we used split-spectrum processing (SSP) combined with matching pursuit signal decomposition (MPSD) to develop a dedicated ultrasonic detection system. SSP algorithm is used for Signal-to-Noise Ratio (SNR) enhancement, and the MPSD algorithm is used to decompose backscattered signals into a linear expansion of chirplet echoes and estimate the chirplet parameters. Therefore, the combination of SSP and MPSD (SSP-MPSD) presents a powerful technique for ultrasonic NDT. The SSP algorithm is achieved by using Gaussian band pass filters. Then, MPSD algorithm uses the Maximum Likelihood Estimation. The good performance of the proposed method is experimentally verified using ultrasonic races acquired from three specimens of carbon fibre reinforced polymer multi-layered composite materials (CFRP).

Development of Ultrasonic Wave Propagation Imaging System

Chia, Chen-Ciang,Lee, Jung-Ryul,Kim, Jong-Heon The Korean Society for Nondestructive Testing 2009 한국비파괴검사학회지 Vol.29 No.4

Laser-based ultrasonic sensing requires the probe with fixed fecal length, but this requirement is not essential in laser-based ultrasonic generation. Based on this fact, we designed a pulsed laser-based ultrasonic wave propagation imaging (UWPI) system with a tilting mirror system for rapid scanning of target, and an in-line band-pass filtering capable of ultrasoaic mode selection. 1D-temporal averaging, 2D-spatial averaging, and 3D-data structure building algorithms were developed far clearer results allowing fur higher damage detectability. The imaging results on a flat stainless steel plate were presented in movie and snapshot formats which showed the propagation of ultrasound visible as a concentric wavefield emerging from the location of an ultrasonic sensor. A hole in the plate with a diameter of 1 mm was indicated by the scattering wavefields. The results showed that this robust UWPI system is independent of focal length and reference data requirements.

The Combined Electrokinetic and Ultrasonic Remediation of Sand Contaminated with Heavy Metal and Organic Substance

Ha Ik Chung,Byung Sik Chun,Yong Jae Lee 대한토목학회 2006 KSCE journal of civil engineering Vol.10 No.5

In this study, laboratory experiments involving the simple soil flushing, electrokinetic remediation, ultrasonic remediation, and combined electrokinetic and ultrasonic remediation tests were carried out for analysis of transportation and removal mechanism of heavy metal and organic substance in sand soil. The test setup used in this study was made to combine the electrokinetic remediation processor and the ultrasonic remediation processor. The soil specimens were thoroughly mixed with lead of 500 ppm and ethylene glycol of 500 ppm. The test specimen was then subjected to ultrasonic waves at 30㎑ frequency from ultrasonic test setup and to electric power at 1.0V/㎝ from electrokinetic test setup. It is shown that the electrokinetic technique was the most effective to enhance the removal efficiency of heavy metal such as lead and not effective to enhance the removal efficiency of organic substance such as ethylene glycol from contaminated soil; on the other hand the ultrasonic technique was the most effective to enhance the removal efficiency of organic substance such as ethylene glycol and not effective to enhance the removal efficiency of heavy metal such as lead from contaminated soil. This reinforces the view that the combined new technique of these two techniques can be effectively used in removal of organic substance and heavy metal from contaminated ground at the same time.