• Advances in nano research
• /
• 제12권3호
• /
• pp.253-261
• /
• 2022

Numerical modelling of an integrated Carbon NanoTube (CNT) membrane is only achievable if probable deformations and realistic alterations from a perfect CNT membrane are taken into account. Considering the possible forms of CNTs, bending is one of the most probable deformations in these high aspect ratio nanostructures. Hence, investigation of effect associated with bent CNTs are of great interest. In the present study, molecular dynamics simulation is utilized to investigate fluid flow dynamics in deformed CNT membranes, specifically when the tube cross section is not affected. Bending in armchair (5,5) CNT was simulated using Tersoff potential, prior to flow rate investigation. Also, to study effect of inclined entry of the CNT to the membrane wall, argon flow through generated inclined CNT membranes is examined. The results show significant variation in both cases, which can be interpreted as counter-intuitive, since the cross section of the CNT was not deformed in either case. The distribution of fluid-fluid and fluid-wall interaction potential is investigated to explain the anomalous behavior of the flow rate versus bending angle.

• Journal of Chest Surgery
• /
• 제20권1호
• /
• pp.161-170
• /
• 1987

Fifty-nine cases of congenital chest wall defects experienced in the department of thoracic surgery of Seoul National University Hospital were analyzed and the relevant literatures were reviewed. They are 52 cases of funnel chest, 3 cases of pigeon breast, one case of superior sternal fissure, one case of costochondral incurvation, one case of Cantrell`s pentalogy, and one case of Poland`s syndrome. Funnel chest affected males more frequently than females by 44 to 8. All of the funnel deformities were corrected by Ravitch operation or its modification except one which was the first case of this series and was corrected by a sterno-turnover. Two cases required a mechanical ventilation for 3 days and 5 days respectively. Four minor complications which were two cases of skin wound infection and 2 cases of fluid accumulation were noted. Skin would infection was repaired by a secondary closure and fluid accumulation was treated by aspiration only. The result are all excellent without recurrence or reoperation. In 3 cases of pigeon breast, they were treated by subperichondrial resection of all of the involved costal cartilages and shortening their course with reefing sutures in the perichondrium with excellent result. The superior sternal fissure which was combined by a ventricular septal defect was treated by a simple wire closure with a good result. The costochondral incurvation was corrected by subperichondrial resection of deformed cartilages and a rib graft removed from the contralateral normal side. The Poland syndrome and the Cantrell`s pentalogy was already presented previously.

• Imaging Science in Dentistry
• /
• 제37권3호
• /
• pp.171-180
• /
• 2007

The role of radiographic imaging in determining the size, numbers and the position of implants is very important. To perform the implant procedure, the dentist needs to evaluate the bone pathology and bone density, and to know the precise height, width, and contour of the alveolar process, as well as its relationship to the maxillary sinus and mandibular canal. The author analyzed 3 implant cases for treatment planning with the cone beam CT. All axial, panoramic, serial and buccolingual-sectioned images of 3 cases with stent including vertical marker were taken by using Mercuray (Hitachi, Japan). When the curved line drawn intentionally did not include dot image of a vertical marker on the axial image of CBCT, the image of the vertical marker was deformed on its buccolingually sectioned image. There was wide discrepancy in inclination between the alveolar bone and tooth on buccolingually sectioned image.

• Journal of Chest Surgery
• /
• 제18권3호
• /
• pp.492-496
• /
• 1985

Two cases of surgical correction of funnel chest using metal struts were presented. The main procedures of the method were transverse submammary incision, subperichondrial resection of the deformed costal cartilages, division of the xiphisternal joint, wedge osteotomy of the sternum, freeing of the posterior surface of the sternum and stabilization by means of 2 metal struts. The struts were removed postoperative 3 and 6 months by a small incision under the local anesthesia. The results in both patients were satisfactory. This method of correction is simple, easy to perform and free of any operative risks.

• Smart Structures and Systems
• /
• 제18권1호
• /
• pp.139-154
• /
• 2016

This paper is concerned with the dynamics of hyperelastic solids and structures. We seek for a smart control actuation that produces a desired (prescribed) displacement field in the presence of transient imposed forces. In the literature, this problem is denoted as displacement tracking, or also as shape morphing problem. One talks about shape control, when the displacements to be tracked do vanish. In the present paper, it is assumed that the control actuation is provided by imposed eigenstrains, e.g., by the electric field in piezoelectric actuators, or by thermal actuators, or via analogous physical effects, such as magneto-striction or pre-stress. Structures with a controlled eigenstrain-type actuation belong to the class of smart structures. The action of the eigenstrains can be conveniently characterized by actuation stresses. Our theoretical derivations are performed in the framework of the theory of small incremental dynamic deformations superimposed upon a statically pre-deformed configuration of a hyperelastic solid or structure. We particularly ask for a distribution of incremental actuation stresses, such that the incremental displacements follow exactly a prescribed trajectory field, despite the imposed incremental forces are present. An exact solution of this problem is presented under the assumption that the actuation stresses can be tailored freely and applied everywhere within the body. Extending a Neumann-type solution strategy, it is shown that the actuation stresses due to the distributed control eigenstrains must satisfy certain quasi-static equilibrium conditions, where auxiliary body-forces and auxiliary surface tractions are to be taken into account. The latter auxiliary loading can be directly computed from the imposed forces and from the desired displacement field to be tracked. Hence, despite the problem is a dynamic one, a straightforward computation of proper actuator distributions can be obtained in the framework of quasi-static equilibrium conditions. Necessary conditions for the functioning of this concept are presented. Particularly, it must be required that the intermediate configuration is infinitesimally superstable. Previous results of our group for the case of shape control and displacement tracking in linear elastic structures are included as special cases. The high potential of the solution is demonstrated via Finite Element computations for an irregularly shaped four-corner plate in a state of plain strain.

• Archives of Plastic Surgery
• /
• 제33권2호
• /
• pp.135-143
• /
• 2006

The characteristics of the cleft lip nasal deformity is defined in this article in three planes. The alar flaring is explained in X axis, the lower positioning of the alar free margin is imagined in Y axis and the short hemicolumella is in Z axis. Most cleft surgeons have focused on the malposition of the lateral crus of alar cartilage while the author defined it in X and Y axises and tried to correct that deformity of short hemicolumella in Z axis. For the last 13 years the author applied that method in 818 cases of secondary cleft lip nose deformity. Through the columellar splitting incision extended to free margin of the alar not beyond the nasal dorsum, the skin and soft tissue of the webbing deformed the nasal tip was excised in crescent fashion. The dissected short hemicolumella including the medial crus was thus elevated and advanced into the space of the deformed nasal tip after the crescent excision. This procedure should be followed by the correction of the deformities in X and Y axis. The medial crus elevation is more effective and critical way to have the constant and nice outcome than the lateral crus reposition in secondary cleft lip nasal deformity

• Structural Engineering and Mechanics
• /
• 제67권1호
• /
• pp.53-67
• /
• 2018

The changes of parameters of pressure and velocity of propagation of elastic pressure and shear waves in uniformly deformed solid compressible media are studied within the nonclassically linearized approach (NLA) of nonlinear elastodynamics to create a new theoretical basis of the geomechanical interpretation of various groups of geophysical observational and experimental data. The cases of small and large deformations are considered while their describing by various elastic potentials, i.e., problems considering the physical and geometric nonlinearity. Convenient analytical formulae are obtained to calculate the indicated parameters in the deformed isotropic media within the nonclassical linear and nonlinear solution in the NLA. Specific numerical experiments are conducted in case of overall compression of various materials. It is shown that the method (generally accepted in the studies of mechanics of standard constructional materials) of additional linearization (relative to the pressure parameter) in the basic correlations of the NLA introduces substantial quantitative and qualitative errors into the results at significant preliminary deformations. The influences of the physical and geometric nonlinearity on the studied characteristics of the medium are large in various materials and differ qualitatively. The contribution of nonlinear components to the values of the considered parameters prevails over linear components at large deformations. When certain critical values of compression deformations in the medium are achieved, elastic waves with actual velocity cannot propagate in it. The values of the critical deformations for pressure and shear waves differ within different elastic potentials and variants of the theory of initial deformations.

• Journal of Chest Surgery
• /
• 제19권3호
• /
• pp.391-398
• /
• 1986

From Jan. 1983 to Dec. 1985, seven cases of pectus excavatum, six were male and one female, were underwent an operation at the Department of Thoracic and Cardiovascular Surgery, Kyungpook National University Hospital. The ages of patients ranged from 6 to 27 years. They all had symptoms of feeling inferiority about chest deformity. The concavity on the funnel chest varied in its extent, and the severity, which was measured by water volume filled into it, varied from 59.5cc/m2 to 129.9cc/m2. All but one patients were approached through a bilateral transverse submammary incision and one approached through a vertical midline incision. Successful surgical correction required resection of all deformed costal cartilages with transverse anterior osteotomy and internal fixation using retrosternal metal bar. No serious complication have followed the use of this technique, but minor complications such as serous accumulation, pneumothorax and strut migration have been experienced. All patients were satisfactory about the surgical results.

• 한국지반신소재학회논문집
• /
• 제12권4호
• /
• pp.77-86
• /
• 2013

본 연구에서는 지지부재가 설치된 띠형 강보강재에 대한 실내인발시험을 수행하였다. 주문진 표준사를 사용하여 상대밀도 80%인 모형지반을 조성하였고, 지지부재의 개수를 0~2개로 구분하여 실내인발시험을 수행하였다. 상재압은 $50kN/m^2{\sim}200kN/m^2$까지 4단계로 구분하여 적용하였고, 1mm/min 속도로 강보강재를 인발하였다. 표면이 매끄러운 띠형 강보강재의 인발저항력은 보강재 표면과 지반 사이에서 마찰저항만 발현되기 때문에 인발 초기에 급격히 증가하다가 지속적으로 감소하는 경향을 나타낸다. 반면, 지지부재를 설치한 강보강재의 인발저항력은 마찰저항뿐만 아니라 수동저항도 함께 발현되므로 계속적으로 증가하는 것으로 나타났다. 보강재의 형태에 관계없이 최대인발저항은 상재압이 증가함에 따라 선형적으로 증가하는 것으로 나타났다. 지지부재를 1개 설치한 경우에 비해 지지부재를 2개 설치했을 때의 최대수동저항은 작게 나타났다. 이는 지지부재의 설치 간격 및 위치에 따라 지지부재에서 발현되는 수동저항의 크기가 다르기 때문에 나타나는 현상으로 판단되며, 지지부재 설치 위치 및 간격에 따른 추가 인발시험을 통해 확인할 필요가 있다.

• 한국재료학회지
• /
• 제5권2호
• /
• pp.184-190
• /
• 1995

IN 617의 시편으로 1073K의 온도에서 주로 107과 180MPA의 응력에서 $\varepsilon$=0.03-0.30까지 정압크립변형을 하여, 투과전자현미경(TEM)에서 약 십만배의 배율로 아결정립의 전위간 거리 s를 측정하고, TEM에서 측정이 불가능한 경우, 아결정립계가 이루는 각도 ($\theta$_{s}=sin^{-1}$(b/s))를 Kikuchi line을 이용하여 측정하였다. TEM에서 직접 구한 s 값들을 $\theta$_{s}$값으로 환산하여, Kikuchi line으로 측정한 $\theta$_{k}$값을 비교한 결과 거의 같았다.즉, TEM에서 s의 측정이 불가능할 때, $\theta$_{k}$를 측정하여 s값으로 사용하여도 됨을 알 수 있었다.