임플랜트 표면처리가 생체활성에 미치는 영향

이호진,송광엽,윤태호,Lee, Ho-Jin,Song, Kwang-Yeob,Yoon, Tae-Ho 대한치과보철학회 2006 대한치과보철학회지 Vol.44 No.5

Statement of problem: Modification of titanium implant surface has potential to ensure clinically favorable performance that several surface modification technologies have been introduced. Among the methods. anodizing method and sol-gel hydroxyapatite coating method have gained much interest due to its roughness and chemical composition of the coating layer, but more of its biocompatibility result is required. Purpose : The purpose of this study was to compare bone-implant interface shear strength of four different surface treated implants as time elapsed. Resonance frequency analysis(RFA) and removal torque measurement methods were employed to measure implant stability at one week and six week after implantation. Material and method: A total of 80 screw-shaped implant [20 machined, 20 resorbable media blasted(RBM), 20 anodized, and 20 anodized+hydroxyapatite sol-gel coated] were prepared, and one of each group was implanted in the tibia of a New Zealand white rabbit that total 20 of them were used. In order to test the implant stability and implant-tissue interface contact changing in the bone bed, each 10 rabbit were sacrificed 1 week and 6 week later while resonance frequency and removal torque were measured. One-way analysis of variance and the Tukey test were used for statistical analysis. Results : The results were as follows. 1. There was no statistically significant difference of implant stability quotients(ISQ) value in RFA between individual groups after 1 week of implantation and 6 weeks(p>0.05). But, there was statistically significant increase of ISQ value in 6 weeks group compared to 1 week group(p<0.05). 2. There was no statistically significant difference in removal torque analysis between individual groups after 1 week of implantation and 6 weeks(p>0.05). but there was statistically significant increase in all 4 groups after 6 weeks compared to 1 week later(p<0.05). 3. There was no statistically significant difference in removal torque analysis between anodized group and HA coating after anodic oxidation 6 weeks later(p>0.05), but significant difference was appeared in both groups compared to RBM group and smooth-machined group(p<0.05). Conclusions : It can be suggested that changes in surface characteristics affect bone reactions. Anodized and anodized+hydroxyapatite sol-gel coating showed significantly improved bone tissue response to implants, but further study on the effect of hydroxyapatite dissolution is needed.

Frequency Map Analysis를 통한 전자 저장링에서의 공명효과 연구

황지광,김은산 한국물리학회 2011 새물리 Vol.61 No.2

A frequency map analysis (FMA) is used to investigate the nonlinear effects in an electron storage ring. For the FMA, we observed the tune shifts caused by dipole magnets, quadrupoles magnets and sextupole magnets. The electron has a large amplitude when the tune is across resonance lines. In that case, the electron was lost at a chamber wall. We investigated the nonlinear effects in the Pohang Light Source-II, which is an upgrade project of a 3-GeV storage ring that has a 5.8-nm-rad emittance. PLS-II has 6.8-m-long and 3.7-m-long straight sections in one cell for installation of insertion devices. In this paper, we discuss resonance effects in the PLS-II. Frequency map analysis(FMA)은 전자 저장링에서의 공명에 의한 비선형효과들을 연구하기 위해서 주로 사용되는 방법으로 저장링에 입사된 전자번치의 초기 진폭에 따라 이극 및 사극, 육극 자석등에 의해 발생하는비선형 효과에 의한 튠 변동의 조사를 통해 분석된다. 베타트론 튠이변동되면서 공명을 일으키게 되면 갑작스럽게 큰 튠 변동이 발생하며이런 경우 전자 번치는 큰 진폭을 가지게 되어 챔버 벽에 부딪혀 전자의손실이 발생하게 될 확률이 높아진다. 우리는 12개의 긴 직선 구간 및12개의 짧은 직선구간을 가지도록 설계되고 있는 포항 방사광가속기(PLS-II)에서의 이러한 효과를 조사하였다. PLS-II는 281.82m의길이에 5.8nm-rad 에미턴스를 가지는 3 GeV 전자링이며 총 12개의 셀로구성되어 있고 한 셀 당 2개의 이극자석 및 4개의 사극자석, 4개의육극자석으로 구성되어 있다. 이 논문에서는 PLS-II에서의 공명효과들을조사하여 논의하였다.

MEMS 공진기의 고주파 응답해석을 위한 고효율 해석기

고진환(Jin Hwan Ko),Zhaojun Bai 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5

A modern MEMS resonator is a micro-scale structure operated over a high frequency range. In order to predict its resonant behavior in a design process, High-frequency response analysis (Hi-FRA) is demanded. Algebraic substructuring (AS) is known as a fast numerical technique to construct an eigenspace for FR and frequency sweep (FS) algorithm efficiently solves the frequency response system projected on the eigenspace. However, the existing FS algorithm using AS is developed for low-FRA, say over the range 1㎐-2㎑. In this work, we extend the FS algorithm using AS for FRA over an arbitrary frequency range. Therefore, it can be efficiently applied to systems operated at a high frequency, say over the range 230㎒-250㎒. The success of the proposed method is demonstrated by Hi-FRA of a checkerboard resonator.

주파수 유연화 운영에 따른 발전기 축 비틀림에 관한 연구

조윤성(Yoon-Sung Cho) 한국조명·전기설비학회 2015 조명·전기설비학회논문지 Vol.29 No.4

Subsynchronous Resonance is a condition where the electrical power systems composed of generator and transmission line exchange energy with mechanical turbine-generator system at the frequency of the combined below the subsynchronous frequency. Therefore, the frequency of power systems should be associated with the subsynchronous resonance. This paper describes subsynchronous resonance by flexible frequency operation. It focuses on the characteristics and behavior of subsynchronous resonance. The subsynchronous resonance is being conducted by real-time digital simulator and the IEEE benchmark model for subsynchronous resonance have been utilized for the test systems.

다양한 가상 골 결함에 따른 공진 주파수의 비교 분석

김상미,박찬진,이양진,장범석,조리라,Kim Sang-Mi,Park Chan-Jin,Yi Yang-Jin,Chang Beom-Seok,Cho Lee-Ra 대한치과보철학회 2005 대한치과보철학회지 Vol.43 No.4

Purpose: Resonance frequency analysis (RFA) , a non-invasive technique for the clinical measurement of implant stability, was investigated. Peri-implant bony defect may contribute to implant failure. This in vitro study evaluated the resonance frequencies according to various bony defects and determined whether the directional bone defect can affect the value of frequency analysis. Material and Method: Fifteen 3.75 mm in diameter and 10 mm in length, machined self-tapping implant future were used. Twelve types of bone defects that have different horizontal and vertical dimensions were simulated. Embedded implants were attached to the dental surveyor. Then, the transducer was connected with the implant fixture and the ISQ value was measured at four different directions. Two-way analysis of variance and post hoc $Sch\`{e}ffe'$ test were performed at the 95% significance level. Results: The control group showed the highest ISQ value and 5 thread-$360^{\circ}$ group had the lowest one. As the vertical exposure of implants in each angle was increased, the ISQ value was decreased. Although the horizontal exposure in each thread was increased, the ISQ value was not significantly decreased. Conclusion : Although the simulated defect type was different from each other, the ISQ value was similar among groups.

보일러 튜브군의 음향공진 회피를 위한 음향배플의 위치에 따른 FEM 음향모드해석

안성종(Sung Jong Ahn),주영호(Young Ho Ju),김철홍(Cheol Hong Kim) 한국소음진동공학회 2012 한국소음진동공학회 학술대회논문집 Vol.2012 No.4

A flow induced mechanical vibration and acoustic resonance should be considered at design stage because they are mainly occurred in the tube bank of boiler. Acoustic resonance is occurred when the vortex shedding frequency of tube bank coincides with the acoustic natural frequency of the cavity. Effective solution to avoid acoustic resonance is installing acoustic baffles in the tube banks parallelly inside of the flow cavity. Thus, location and number of acoustic baffles should be exactly calculated to eliminate the acoustic resonance. This paper presents case study of acoustic resonance due to inappropriate number and location of acoustic baffles. Measured frequency and mode in the study is verified by FEM acoustic modal analysis. The number and location of acoustic baffles to avoid acoustic resonance are calculated by using FEM acoustic modal analysis.

다양한 양극산화막 처리방법이 임플란트 골유착에 미치는 영향

권경환,민승기,성대혁,최재영,최성림,차수련,오희균,Kwon, Kyung-Hwan,Min, Seung-Ki,Sung, Dae-Hyuk,Choi, Jae-Young,Choi, Seung-Lim,Cha, Su-Ryeon,Oh, Hee-Kyun 대한악안면성형재건외과학회 2007 Maxillofacial Plastic Reconstructive Surgery Vol.29 No.5

The aim of the present study is to investigate the effect of anodized surface of osseointegration implants by using of resonance frequency analysis (RFA) and histomorphometric analysis. A total of 96 screw-shaped implants were devided into 4 groups. Seventy-two implants were prepared by electrochemical oxidation with 3 different ways; Group 1 (n=24) were prepared at galvanostatic mode in 0.25M sulfuric acid and phosphoric acid, Group 2 (n=24) were prepared at galvanostatic mode in calcium glycerophosphate and calcium acetate, and Group 3 (n=24) were prepared at galvanostatic mode in 0.25M sulfuric acid and phosphoric acid followed by Calcium metaphosphate(CMP) coating. Control group (n=24) were the RBM surfaced implants. The implants were placed in the mandibles of 12 mini pigs. Bone tissue responses were evaluated by resonance frequency analysis(RFA) and histomorphometric analysis that were undertaken at 2, 4 and 6weeks after implant placement. The following result were obtained. 1. Twenty-two of 96 implants (4 in control group, 5 in group 1, 7 in group 2, and 6 in group 3) were failed due to faliure of osseoitegration. The failure rate of osseointegration was 22.9%. 2. The mean values of RFA in control, group 2 and groups 3 showed the similar values, but there was no significant difference among groups. 3. Histomorphometric evaluation demonstrated significantly higher bone-to-implant contact ratio in group 2 at 3 and 4 weeks after implant placement than other groups (p<0.05), but there was no significant difference among groups at 6weeks after implant placement.

회전 압축기와 왕복동식 압축기의 쉘 내부공간 공명 소음 저감법

이병찬 忠州大學校 2003 한국교통대학교 논문집 Vol.38 No.2

This study is about noise reduction of hermetic rotary compressor in air conditioner and reciprocating compressor in household refrigerator. Especially, it is about method to reduce the low-frequency band noise which is related to shell cavity resonance. The method of reducing noise for the same shell cavity resonance in rotary compressor and reciprocating compressor is different from each other. Shell cavity resonance frequencies are derived from experiments and analyses. The position of discharge muffler outlet hole is determined to minimize cavity resonance in the rotary compressor. The cavity resonance modes of hermetic reciprocating compressor are the major factors of the 400 ~ 630Hz in 1/3 octave band noise spectrum. Di-pole type cavity modes make high contribution to the total noise level in the reciprocating compressor. In order to avoid shell cavity resonance frequencies under reciprocating compressor operating condition, new shell design is made.

임프란트 식립시 초기 안정성이 골유착에 미치는 영향

이영훈,김여갑,최병준,Lee, Young-Hoon,Kim, Yeo-Gab,Choi, Byung-Jun 대한악안면성형재건외과학회 2008 Maxillofacial Plastic Reconstructive Surgery Vol.30 No.6

Purpose: The long-term experience of using osseointegrated implants for prosthetic rehabilitation of the edentulous patients shows that high success rates can be predictably achieved. Primary implant stability has been identified to be a prerequisite to achieve osseointegration. In this study, we set up the amount of removed bone so that it differed on implant installation site for each group. The influence of each initial stability on secondary stability and osseointegration was compared with time lapse using resonance frequency analysis and histomorphometric analysis. Materials and methods: A total 27 US $II^{(R)}$ (Osstem, Korea) implants were placed in the mandibular edentulous area of 3 beagle dogs. The implant site was prepared by the conventional technique with drills, and three experimental groups were divided into under-drilling group, normal-drilling group and over-drilling group. The Implant Stability Quotient (ISQ) was measured at intervals of immediately, 4, 8, 12 weeks after placement using $Osstell^{(R)}$ mentor RFA. After the animals were sacrificed, histomorphometric evaluation was executed for measuring BIC and BD. Results: 1) The under-drilled group showed most high ISQ value for whole experiment period. 2) Bone-to-implant-contact(BIC) showed the tendency to be increased gradually as the experiment period passed except the 8 weeks of the normal group. 3) The under-drilled group showed most high bone density(BD) level for whole experiment period, and it was expressed the aspect to be increased gradually according to an experiment period passage in the average of all group. 4) Resonance frequency analysis and histomorphometric analysis are presumed by generally proportional. Conclusions: As this research result, it seems that there are some correlation between resonance frequency analysis and histomorphometric analysis. As are accomplished osseointegration stably so that more superior at the region which the overpressure comes to add, it will be applicable method in clinical field.

공진회피를 위한 철도차량의 고유진동수 해석 및 측정에 관한 연구

홍도관(Hong, Do-Kwan),정재부(Jeong, Jae-Boo),정승욱(Jung, Seung-Wook),김경배(Kim, Gyeong-Bae),안찬우(Ahn, Chan-Woo) 한국소음진동공학회 2012 한국소음진동공학회 논문집 Vol.22 No.8

This paper deals with the natural frequency analysis and two experiments to evaluate first twisting and bending natural frequency of railway vehicle. The KS R 9228 testing method is generally performed as pseudo FRF(frequency response function) which is widely used by two accelerometers. The exciting method is utilized using the load weight(1 ton release). The modal testing is used to verify KS R 9228 testing result and the natural frequency analysis result. The first twisting and bending natural frequency should be above 10 Hz by resonance which is mostly generated between bogie and vehicle frame exciting low frequency. The first twisting and bending natural frequency of railway vehicle are successfully verified between analysis and test.