• 보존과학회지
• /
• 제25권1호
• /
• pp.87-100
• /
• 2009

알칼리화강암으로 구성된 경주 남산 삼릉계곡 선각육존불 주변 암반을 대상으로 보존처리제 성능을 평가하였다. 이 연구에 적용된 보존처리제는 에틸실리케이트 계열의 암석 강화용 처리제와 에폭시 계열의 수지이다. 처리과정은 에폭시 계열의 수지를 박리면에 주입 후 암석 강화용 처리제를 총 3차례 도포 하였으며, 처리 전과 후의 물성 변화를 비교하기 위해 초음파 속도를 측정하였다. 초음파속도 측정 결과, 박리면 주변의 저속도대는 강화제 및 충전제 처리 후 평균 27.8%의 속도 증가가 나타났다. 이 결과는 석조문화재에 대한 보존처리제의 강화 효과를 입증하는 것으로서, 최소 3회 정도를 처리하는 것이 효과를 극대화 시키는 것으로 나타났다.

• 비파괴검사학회지
• /
• 제34권3호
• /
• pp.241-247
• /
• 2014

본 연구는 고온강도와 화학적 안전성으로 산업기계 구조물의 주요 소재로 사용되고 있는 AISI316 오스테나이트기 스테인레스강의 장시간 등온열처리에 따른 초음파 비선형성 특성을 평가하였다. 장시간 등온열처리는 정해진 시간을 변수로 전기로에서 가속열처리를 수행하였다. 미세조직적으로 정밀분성을 통하여 장시간 열처리에 따른 초음파 비선형성의 변화와 미시적 손상거동을 면밀히 평가하였다. 초음파 비선형성은 1000시간까지 급격하게 감소하고 이후 서서히 감소하였다. 표면조직적으로 입계의 모양이 다각형에서 원형으로 변하며 특히, 1000시간에서는 쌍정이 모두 분해되었다. 입계에 존재하던 델타페라이트는 1000시간에서 관찰되지 않으며 ${\sigma}$상으로 지속적인 변태가 진행되었다. 결과적으로 열처리 초기에는 보이드나 전위의 소멸 그리고 쌍정의 소멸로 초음파 비선형성은 급격히 감소를 하고 이후에는 입계에 $Cr_{23}C_6$석출물의 생성과 ${\sigma}$상 생성으로 초음파 비선형성은 미소하지만 지속적으로 감소한 것으로 판단된다.

• 한국인터넷방송통신학회논문지
• /
• 제18권4호
• /
• pp.143-147
• /
• 2018

수위는 하수장, 정수장, 하천, 댐, 공장의 저장탱크 등 다양한 분야에서 측정된다. 수위측정을 위한 초음파 기기가 판매중이나 산업용으로 실험에서 사용하기는 가격이 너무 비싸다. 전자 기술의 급속한 진보로 인해 다양한 종류의 측정, 모니터링 및 제어 기능이 저렴하게 구축하는 것이 가능해졌다. 저렴한 가격으로 초음파 수위 측정시스템을 만들기 위하여 본 연구가 시작되었다. 실험용으로 사용하기 위하여 아두이노, 초음파 센서 및 온도 센서로 시스템을 구성하였다. 초음파 센서는 센서에서 수위 표면까지의 시간을 측정한다. 온도 센서는 대기 온도를 측정하며 온도 변화로 인한 소리의 속도를 보정하여 초음파 거리 측정의 정확성을 높인다. 아두이노는 측정 전반을 관리하고 수위를 계산한다. 시스템의 모든 구성 요소는 장치거치대에 조립되었다. 제안된 시스템을 가지고 실험한 결과 수위가 실측치와 매우 가까웠다. 이 시스템은 또한 저렴하며 설치 및 유지하기가 쉬워 실험용으로 적절하다.

• Journal of Korean Neurosurgical Society
• /
• 제66권4호
• /
• pp.426-437
• /
• 2023

Objective : To investigate the efficacy and safety of the posterior endoscopic cervical foraminotomy (PECF) using ultrasonic osteotome for the treatment of cervical osseous foraminal stenosis, focusing on introduction of the advantages of ultrasonic osteotome in partial pediculectomy and ventral osteophyte resection in PECF. Methods : Nineteen patients with cervical osseous foraminal stenosis who underwent PECF using ultrasonic osteotome in our institution between April 2018 and April 2021 were enrolled in this study. All the patients were followed up more than 12 months. The patients' medical data, as well as pre- and postoperative radiologic findings were thoroughly investigated. The visual analogue score (VAS), Japanese Orthopaedic Association (JOA) score, cervical dysfunction index (Neck disability index, NDI), and modified MacNab criteria were used to assess the surgical efficacy. Results : All the patients were successfully treated with PECF using ultrasonic osteotome. The pre- and postoperative VAS, NDI, and JOA scores were significantly improved (p<0.05). According to the modified MacNab criteria, 17 patients were assessed as "excellent", two patients were assessed as "good" at the last follow-up. There was no dura tear, nerve root damage, incision infection, neck deformity, or other complications. Conclusion : Adequate nerve root decompression can be accomplished successfully with the help of ultrasonic osteotome in PECF, which has the advantage of reducing the probability of damage to the nerve root and dura mater, in addition to the original merits of endoscopic surgery.

• 웰빙융합연구
• /
• 제5권4호
• /
• pp.51-56
• /
• 2022

Purpose: By applying an ultrasonic mechanical device to the liquid fertilizer storage in the pig dropping treatment plant, the initial odor of the odor source is reduced, and the air dilution drainage of the complex odor is fundamentally recognized to facilitate odor treatment on the mechanical and chemical biological treatment devices at the rear. Research design, data and methodology: The odor concentration on the site boundary was measured to confirm the state of reduction. In order to prevent the spread of odor from the collection of the pig dropping treatment plant, it was measured by installing an ultrasonic generator inside the installation wall after installing the sealing wall. Results: The average value of the March and April measurement data remained close to neutral at 8.2 after 8.6 treatment before pH treatment, decreased 97.3% from 462 mg/L before SS treatment to 10.5 mg/L after treatment, and the composite odor was reduced by 85% from 20 to 3 before treatment. It was confirmed that ammonia (NH3) was reduced by 99% from 5.8 ppm to 0.09 ppm, and general bacteria were also reduced by 99% from 3,200 CFU/mL to 57 CFU/mL Conclusion: Applying the ultrasonic air ejector hybrid system and zigzag air complex module development product to resource circulation centers or sewage treatment facilities is thought to reduce inconvenience to residents due to odors caused.

• 비파괴검사학회지
• /
• 제37권2호
• /
• pp.115-121
• /
• 2017

The nonlinear ultrasonic technique is a potential nondestructive method to evaluate material degradation, in which the ultrasonic nonlinearity parameter is usually measured. The ultrasonic nonlinearity parameter is defined by the elastic nonlinearity coefficients of the nonlinear Hooke's equation. Therefore, even though the ultrasonic nonlinearity parameter is not equal to the elastic nonlinearity parameter, they have a close relationship. However, there has been no experimental verification of the relationship between the ultrasonic and elastic nonlinearity parameters. In this study, the relationship is experimentally verified for a heat-treated aluminum alloy. Specimens of the aluminum alloy were heat-treated at $300^{\circ}C$ for different periods of time (0, 1, 2, 5, 10, 20, and 50 h). The relative ultrasonic nonlinearity parameter of each specimen was then measured, and the elastic nonlinearity parameter was determined by fitting the stress-strain curve obtained from a tensile test to the 5th-order-polynomial nonlinear Hooke's equation. The results showed that the variations in these parameters were in good agreement with each other.

• 물과 미래
• /
• 제26권1호
• /
• pp.63-69
• /
• 1993

매립이 완료된 Landfills이나 오염된 지하수의 오염물질을 제거하여 다른 용도로 재사용하는 기술이 오늘날 중요한 문제로 대두되고 있다. 진동을 이용하여 제가효율을 높히는 방법은 요즘 흔히 사용되고 있는 방법중의 하나이다. Ultrasonic의 효과를 사용함으로써, 기계적인 제거효과가 대단하다는 것은 이미 몇몇 연구자들에 의해 확인된바 있다. 이 연구에서는 Probe-Type Lutrasonic Processor를 사용하여 Clayey-Sand Chamber를 가지고 실험을 해보았다. 실험중 계속적인 Pumping과 함께 Ultrasonic을 작동시킨 결과, Clayey 입자들의 분리 및 제거에 큰 효과를 얻었으며, 그로 인하여 투수계수가 크게 증가하는 효과를 보았다. 또한, 실험 전과 후의 입자크기의 분포도가 크게 변했는데, 그 이유는 Ultrasonic의 진동효과 때문이다. 실험결과, 0.004mm 이하의 입자들은 Ultrasonic의 효과에 의해 Mobilize되었으며, 0.04-1.0mm의 입자는 부서져서 작은 입자로 되었다. 이 기구를 사용하기 위한 유지비와 전력비등을 고려하여 이 기구의 실용성을 검토해 보았다. 필요한 Power를 위해 요구되는 전력의 양은 깊이에 의한 대상 site의 응력, 온도, 그리고 Fuid의 Viscosity에 의해 좌우되며, 그중 가장 큰 영향을 미치는 요소는 흙의 깊이이다. 여러 가지의 다른 깊이에서의 경제적인 실용성을 1.0, 2.0in 직경의 Horn Sonicator를 사용했을 경우에 대하여 비교와 분석을 하였다.

• 상하수도학회지
• /
• 제27권4호
• /
• pp.457-468
• /
• 2013

Based on the activated sludge model(ASM), a mathematical model which represents the aerobic sludge digestion by sequencing batch reactor(SBR) combined with ultrasonic treatment was composed and performed in this study. Aerobic digestion using sequencing batch reactor(SBR) equipped with ultrasound treatment was also experimented for the purpose of parameter calibration. Most of the presented kinetic parameters in ASM or ASM2 could be used for the aerobic digestion of sludge but the parameters related in hydrolysis and decay rate needed modification. Hydrolysis rate constant of organic matter in aerobic condition was estimated at $0.3day^{-1}$ and the maximum growth rate for autotrophs in aerobic condition was $0.618day^{-1}$. Solubilization reactions of particulate organics and nitrogen by ultrasonication was added in this kinetic model. The solubilization rate is considered to be proportional to the specific energy which is defined by specific ultrasound power and sonication time. The solubilization rate constant by ultrasonication was estimated at $0.202(W/L)^{-1}day^{-1}$ in this study. Autotrophs as well as heterotrophs also decomposed by ultrasonic treatment and the nitrification reaction was limited by the lack of autotrophs accumulation in the digester.

• Journal of Oral Medicine and Pain
• /
• 제16권1호
• /
• pp.103-111
• /
• 1991

This study was performed to observe the effect of micro-wave diathermy and ultrasonic-wave diathermy on the craniomandibular disorder patients. 19 patients were classified into 12 acute and 7 chronic groups according to the duration of 6 months. They were treated with micro-wave diathermy and ultrasonic-wave diathermy for 2 weeks and pain, maximum comfortable opening, active range of motion were checked before and after therapy. Electromyographic activities of temporal and masseter muscles were also measured at physiologic rest position, clenching and mastication before and after therapy. The obtained results were as follows : 1. After treatment, pain were reduced and active range of motion and maximum comfortable opening were increased. 2. Temporoal and masseter muscle activities of post-treatment in rest position, clenching and mastication were lower than those of pre-treatment. 3. In rest position, temporal and masseter muscle activities of pre-treatment on affected sides were higher than those on unaffected sides, but there were no differences in muscle activities between affected ad unaffected sides on clenching and mastication in pre and post-treatment respectively. 4. There were no significant differences in active range of motion, pain and maximum comfortable opening between acute and chronic groups in pre and post-treatment but there were significant differences between pre-treatment and post-treatment in acute and chronic groups respectively. 5. Muscle activities of masseter and temporal muscles in acute and chronic patients were reduced in rest position after treatment.

• 한국표면공학회지
• /
• 제43권5호
• /
• pp.243-247
• /
• 2010

The micro Vickers hardness and internal stress of Ni-Fe metal thin film synthesized by electrodeposition method at $25^{\circ}C$ were studied as a function of bath composition, and surface microstructure and atomic compositions of thin films were investigated by SEM and EDS. And the shape change of $200\;{\AA}$ Ni-Fe nanowires made using anodic aluminum oxide(AAO) templates by electrodeposition method were observed by SEM as a function of ultrasonic treatment time and bath composition. The Fe deposition contents on the substrate non-linearly increased with Fe ion concentration over total metal ion concentration. In case of low Fe contents film, the grain size is smaller and denser than high Fe contents deposited films, and the micro Vickers hardness increased with Fe contents of electrodeposited films. These results affected the shape change of nanowire after ultrasonic treatments.