http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : 성기웅 (검색결과 15 건)
-
-
-
플로팅 매스 타입의 진동체가 이식된 중이의 전달특성 예측모델
Recently, implantable middle ear hearing devices (IMEHDs) have been actively studied as an alternative to conventional hearing aids. The IMEHDs consist of a microphone, a signal processor, and a vibration transducer. The floating mass type transducer, an output device of IMEHDs, is implanted with a clip on a human ossicular chain by means of middle ear surgery, and transmits a mechanical vibration to the stapes. Therefore, the vibration characteristics of transducer have been designed to be similar with that of normal stapes, which is regulated on the ASTM (American society for testing and materials)-F2504. However, the vibration characteristic of stapes, driven by the implanted floating mass type transducer, is different from the transducer itself because vibration transmitted to the stapes is affected by the mechanical coupling between the transducer and the ossicular chain. It is necessary to analyze the vibration characteristics of stapes after implantation of transducer for developing the transducer of IMEHDs. The analysis should be conducted on consideration of the vibration characteristics of transducer as well as middle ear. In this paper, the electrical model of human middle ear with an implanted floating mass type transducer is proposed. The vibration characteristics of the stapes, driven by implanted a floating mass type transducer, are analyzed by using the PSpice. First, the mechanical model, which has 5 masses, 9 springs, and 6 dampers, and based on the anatomical structure of the human middle ear, is proposed. Then, Newton's kinetic equation of the mechanical model is translated to the differential equation of electrical model by electro-mechanical equivalence. The electric circuit model of human middle ear is induced from the differential equation by Kirchhoff's voltage law. The passive component values of electric circuit model is optimized to circuit variable, corresponding to stapes vibration velocity, reflecting normal stapes vibration regulated on the ASTM-F2504. Second, the differential floating mass transducer (DFMT), which is an advanced floating mass type transducer, was utilized for combining with suggested middle ear model. DFMT consists of two magnets, a coil, and two vibration membranes. The mechanical model of DFMT was also derived by using Newton's kinetic equation, which has 2 degree of freedom and considered electromotive force. Then, the translated electric circuit model of DFMT combined with that of human middle ear on considering the clip for rigid coupling DFMT and the ossicular chain. The variation of stapes velocity, driven by the DFMT implanted in the human middle ear, is simulated by altering the vibration characteristics of DFMT by changing the physical parameters of transducer; The vibration characteristic of DFMT can be adjusted by varying stiffness of vibration membrane, coil turns and mass of case. The simulated vibration characteristics had been compared with the ex-vivo experimental results by using the fabricated DFMT and human temporal bones. Through the comparison, it is verified that the vibration analysis, using the electrical model, is helpful for predicting the vibration characteristics of stapes driven by DFMT after the implantation. The hearing impaired persons have various type of audiogram, and different frequency band compensation is required. However, the previous transducers were designed without considering the loading effects of the middle ear structures. The proposed model can help to decide the design parameters of the transducer that has ability to enhance the vibration force at desired frequency band. Through the discussions, the vibration characteristic of stapes is influenced by the stiffness of clip, which is used to attach the transducer to the incus. Therefore, additional cadaveric experiments with various type of clip are required. Further study needed to improve the simulation model which includes nonlinear properties of the human ligaments and the muscles in the middle ear.
-
-
구조물의 취약 부에서는 응력이 높게 나타나게 된다. 이러한 부분에 대하여 유한 요소 해석을 할 때 최선의 결과를 얻기 위해서는 전체 구조물을 세밀한 요소 망으로 구성하여 해석하는 것이다. 그러나 너무 세밀하게 유한 요소 망을 구성하게 되면 요소 수의 증가로 인한 해석 시간이 길어져 효율성이 저하되는 단점이 있다. 따라서 보통 응력 집중 부에는 조밀하게 요소 망을 구성하게 되고 응력이 적게 걸리는 부분은 요소 망을 거칠게 구성하여 해석 시간을 단축하는 것이 일반적인 방법이다. 일반적으로 평면 응력 문제에서 응력 집중부의 요소 망을 세밀하게 나누면 사변형 요소의 종횡비가 변화한다던가 삼각형 요소의 사용으로 인하여 요소 수가 증가하게 되고 어떤 경우에는 오히려 해석의 정확성이 저하되기도 한다. 본 논문에서는 이러한 문제를 개선하기 위하여 일반적인 유한 요소 해석의 근간인 변위법을 기본으로 천이 요소의 개념을 도입하여 천이 절점 도입에 따른 형상 함수의 설정 및 강성 행렬 계산을 위한 수치 적분에 필요한 수정된 가우스 적분의 적용에 대하여 연구하였다. 제안한 천이 요소의 유효성을 규명하기 위하여 여러 가지 평면 문제를 해석하고 그 결과를 검토하였다. 연구 결과로 얻은 결론은 다음과 같다. 응력 집중 문제에 천이 요소를 적용하여 해석함으로써 전체 요소 수를 줄일 수 있고 동시에 해석의 정확도를 높일 수 있음을 알았다. It is usual practice to use a relative fine finite element mesh in the area of high stress gradients. This fine element mesh is then changed to a coarser mesh where stresses are relatively uniform. In case of using quadrilateral elements, with poor aspect ratios., and some triangular elements, it does not give an exact result and so it has difficulty in mesh modeling. In this paper, formulation of a transition element is presented. Such an element makes it possible to match one element with two elements side-by-side. A modified quadrature formula is used to numerically integrate discontinuous functions in the expression of the stiffness matrix. Examples presented here are constructed using a basic four node quadrilateral element in which intermediate transition nodes are introduced. As a result of this study, following conclusions are obtained 1) Using transition elements, it can reduce the time to solve a problem. 2) Since interelement compatibility can be secured. The accuracy of an analys is can be improved. 3) Transition elements can make mesh modeling more convenient.
-
-
양이온 UV 金屬 印刷와 코팅製罐 加工 適性 比較 硏究
Recently, the cationic UV curable coating materials have been enough improved to apply the can end and closure as the pre-painted metal sheet(PCM), on which the free-radical UV coat has limited its using because of their drawback of shrinkage. The paints and printing inks within thermal curing way for the crown and cap closures are also believed to be the most significant advancement all the while, however, to be hard to survive and keep the high energy cost in the present rigid rules of VOC and HAP, and the expensive oil price. The UV curable systems are received as a powerful alternative technology to solve such high cost structure and promote productivity. So this study starts to find a way out, experiment and apply commercial UV curable coatings to the closures. Cap closure is made from both coating and succeeding deformation process. It is coated with several painting layers, printing and overprint varnish coating. Then it is pressed in three steps of press called 'deep-drawing'. Therefore the organic coatings should have certain performance and possibilities of the corrosion resistance as well as the maintenance for the aesthetic appearance. And it needs another abilities that can bear up against sterilization stage in the afterward packaging process and that can save the resistance property for existing the quality in some more period. This UV curing experiment was designed and accomplished in the base of such manufacturing and market environment conditions. To avoid the first UV curing experiment risk, the thermal curing system of the size and white coatings were used as they are and the printing and OPV coating were substituted to UV curing system, then these were compared with the thermal cured coatings. Two kinds of coatings were pressed in shop field and tested several qualities in laboratory. Samples were prepared in the following processes : blanks, 1st pressed, 2nd pressed and 3rd of final pressed and analyzed each of them. the microscopic examination was added for the capturing detailed images of cracks and wrinkles come out along the wall of closures. Consequently, the cationic UV curable OPV coating and radical UV ink have adequate performance in this experiment. OPV coats were experienced severe damages if they were not cured enough to endure the friction and a unique shape of serial cracks was appeared. But this can be remedied by thinning the OPV coating thickness. the radical UV printing ink was succeeded in this study without any problem.
-
-
-
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
