• ETRI Journal
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• 제44권1호
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• pp.147-154
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• 2022

We demonstrate a new double-layer structure for stretchable interconnects, where the top surface of a serpentine polyimide support is coated with a thin eutectic gallium-indium liquid metal layer. Because the liquid metal layer is constantly fixed on the solid serpentine body in this liquid-on-solid structure, the overall stretching is accomplished by widening the solid frame itself, with little variation in the total length and cross-sectional area of the current path. Therefore, we can achieve both invariant resistance and infinite fatigue life by combining the stretchable configuration of the underlying body with the freely deformable nature of the top liquid conductor. Further, we fabricated various types of double-layer interconnects as narrow as 10 ㎛ using the roll-painting and lift-off patterning technique based on conventional photolithography and quantitatively validated their beneficial properties. The new interconnecting structure is expected to be widely used in applications requiring high-performance and high-density stretchable circuits owing to its superior reliability and capability to be monolithically integrated with thin-film devices.

• PNF and Movement
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• 제6권1호
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• pp.33-40
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• 2008

Purpose : When the pliability of the Lumbar is degraded, the kinesiology function undergoes an influence and it receives an overload. Finally, it is connected with a Lumbar muscular injury. When it does the regular exercise treatment the lumbago patient the balance and function of changeover are improved. The purpose of this study is to review of effect of the PNF application for lumbago patient Methods : By using internet, we research the PubMed, Science Direct, KISS, DBpia and the article on the effect of PNF. We selected the article between 1970 and 2007. Key words were low back pain, lumbago, PNF. Results : PNF is a therapeutic exercise for central nervous system(CNS) patient and the peripheral nervous system(PNS) patient and it is widely applied from sports medicine in the last. According to research of the Jung Young Jo(2007) and Han Kou Soo(2002), PNF technique improves the pain and a condition of the lumbago patient. And the affection balanced change and dynamic balance change and spontaneous movable scope are improved. And it improved to daily life activity. According to research of Moore and Hutton(1980), Lee Kyoung Hye(1999), PNF stretching where it is one of muscular relaxation is good in lumbar muscle fascia ache solutions, and PNF stretching that muscle is relaxed and increases ROM by Reflective system of the vertebra. These researches is relation all each other. it have appeared many report of research about Pliability, muscular power, balance, mobility improve ADL movement of attendance ability and functional action improved excise therapy put effect about lumbago patient recently, it have appeared research about therapy of lumbago patient through PNF. But PNF technique is not application about lumbago patient in clinic, therefore also it is not enough for case study about this therapy. Conclusion : PNF improve combination operation of muscle, inconvenience decrease from daily life activity, ROM(range of movement) of lumbar is increase and Lumbago reduce. So we suggest that PNF will be applies on the lumbago patient and must do a many research.

• Structural Engineering and Mechanics
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• 제50권4호
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• pp.487-500
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• 2014

An analytical solution for the nonlinear in-plane free oscillations of the suspended cable which contains the quadratic and cubic nonlinearities is investigated via the homotopy analysis method (HAM). Different from the existing analytical technique, the HAM is indeed independent of the small parameter assumption in the nonlinear vibration equation. The nonlinear equation is established by using the extended Hamilton's principle, which takes into account the effects of the geometric nonlinearity and quasi-static stretching. A non-zero equilibrium position term is introduced due to the quadratic nonlinearity in order to guarantee the rule of the solution expression. Therefore, the mth-order analytic solutions of the corresponding equation are explicitly obtained via the HAM. Numerical results show that the approximate solutions obtained by using the HAM are in good agreement with the numerical integrations (i.e., Runge-Kutta method). Moreover, the HAM provides a simple way to adjust and control the convergent regions of the series solutions by means of an auxiliary parameter. Finally, the effects of initial conditions on the linear and nonlinear frequency ratio are investigated.

• Nuclear Engineering and Technology
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• 제49권8호
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• pp.1660-1668
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• 2017

The flow of liquids submerged with nanoparticles is of significance to industrial applications, specifically in nuclear reactors and the cooling of nuclear systems to improve energy efficiency. The application of nanofluids in water-cooled nuclear systems can result in a significant improvement of their economic performance and/or safety margins. Therefore, in this paper, Marangoni thermal convective boundary layer dusty nanoliquid flow across a flat surface in the presence of solar radiation is studied. A two phase dusty liquid model is considered. Unlike classical temperature-dependent heat source effects, an exponential space-dependent heat source aspect is considered. Stretching variables are utilized to transform the prevailing partial differential system into a nonlinear ordinary differential system, which is then solved numerically via the Runge-Kutta-Fehlberg approach coupled with a shooting technique. The roles of physical parameters are focused in momentum and heat transport distributions. Graphical illustrations are also used to consider local and average Nusselt numbers. We examined the results under both linear and quadratic variation of the surface temperature. Our simulations established that the impact of Marangoni flow is useful for an enhancement of the heat transfer rate.

• 한국의류산업학회지
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• 제12권4호
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• pp.500-507
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• 2010

In this study, physical properties were studied by using latent stretching yarn in order to develop the texturing yarn technique for super bulky yarn, which is better in bulkiness and handle than natural wool and also adds property of synthetic fiber to natural wool. In order to obtain textured conditions by analysing basic properties for manufacturing DTY yarn with super bulky property, DTY 50d/12 after spinning latent yarn spined POY 80d/12 was obtained under the two conditions of (i) false twist(T/M) level 3 in DTY texturing and (ii) draw ratio level 4 in draw texturing. For DTY texturing yarn, Elongation rate increased as the heat treatment time and temperatures increased. In addition, shrinkage became higher as false twist was higher, so that elongation rate became lower. When annealing became longer in time and higher in temperature, initial modulus increased. In addition, as the count of false twist increased, the initial modulus showed higher values. For draw texturing yarn, under the conditions of heat temperature 180 and heating time 30 minutes, shrinkage rate in draw ratio 1.55 and 1.6 draw ratio was 7%, and that in 1.65 and 1.7 draw ratio was 8.5%. High draw ratio samples' tenacity was much influenced by heating time and temperature, but low draw ratio samples' tenacity was influenced not by treated time, but by treated temperature.

• 대한기계학회논문집
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• 제11권2호
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• pp.214-221
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• 1987

본 논문에서는 2차원충돌분류에서 사각리브(rib)를 갖는 요철형전열면에 대한 실험에 관한 것이며, 리브의 높이를 (ｅ=5nm) 일정하게 하고 리브의 피치(ｐ=25,35,50 nm) 변화, 노즐출구와 전열면간 거이(H/B=1~14) 및 노즐출구유속(ｕ$_{e}$=12.30~ 18.07m/s)의 변화에 따른 전열특성을 실험적으로 구명하고 평판전열면의 경우와 비교 검토한다. 또한 스모크와이어(smoke-wire)법으로 평판 및 리브판에서의 유체의 거동 을 가시화하여 전열기구의 정성적 특성을 검토하는데 목적이 있다.

• Journal of Oral Medicine and Pain
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• 제25권3호
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• pp.325-329
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• 2000

근막동통은 발통점과 중추흥분효과가 나타나는 국소적 근육성 동통이다. 발통점은 근육의 일부나 건 부착점에 나타나는 부위로서 단단한 띠로서 느껴지고 촉진시 통증을 유발한다. 통증은 관련된 발통점의 위치에 따라 연관된 부위에 나타난다. 이러한 근막 발통점에 따른 증상은 약한 기능이상부터 일상생활이 어렵게 되는 정도의 심한 통증까지 다양하다. 이의 발생에는 국소적 근육이상, 심부 동통, 심리적 스트레스의 증가, 수면장애와 전신적인 요인들도 관여한다. 일반적으로 치료는 보존적인 처치로써, fluoro-methane 같은 vapocoolant spray를 사용하는 사용하여 분사신장하는 방법이 있으며, 국소적인 주사, 마사지, 초음파, 온열요법등이 있다. 여러 환자에서 근막동통을 가지는 환자에 분사신장요법을 시행한 결과 대부분 환자에서 증상의 개선을 보였다. 근막동통의 치료시 분사신장요법은 매우 보존적인 처치로 임상가의 적용과 접근이 쉬우며, 환자로 하여금 치료에 따른 불안감을 줄이면서 만족을 느낄 수 있는 치료로 사료된다. 그러나 만성 환자의 경우 분사신장요법의 치료결과에 대한 만족도가 높지 않았다. 분사신장 용법은 근막동통을 가진 환자 모두에서 효과적이지는 않으나 치료의 도입으로, 근막동통을 진단시에 일차적으로 사용할 수 있는 안정한 보존적인 용법으로 사료된다.

• Bulletin of the Korean Chemical Society
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• 제19권4호
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• pp.422-428
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• 1998

In the present paper, we report a molecular dynamics (MD) simulation of non-rigid zeolite-A framework only as the base case for a consistent study of the role of intraframework interaction on several zeolite-A systems using the same technique in our previous studies of rigid zeolite-A frameworks. Usual bond stretching, bond angle bending, torsional rotational, and non-bonded Lennard-Jones and electrostatic interactions are considered as intraframework interaction potentials. The comparison of experimental and calculated structural parameters confirms the validity of our MD simulation for zeolite-A framework. The radial distribution functions of non-rigid zeolite-A framework atoms characterize the vibrational motion of the framework atoms. Mean square displacements are all periodic with a short period of 0.08 ps and a slow change in the amplitude of the vibration with a long period of 0.53 ps. The displacement auto-correlation (DAC) and neighbor-correlation (DNC) functions describe the up-and-down motion of the framework atoms from the center of α-cage and the back-and-forth motion on each ring window from the center of each window. The DAC and DNC functions of the framework atoms from the center of α-cage at the 8-ring windows have the same period of the up-and-down motion, but those functions from the center of 8-ring window at the 8-ring windows are of different periods of the back-and-forth motion.

• Design & Manufacturing
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• 제13권3호
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• pp.1-11
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• 2019

Recently, studies on the development of flexible electronic devices by combining flexible materials and a conductor have been actively performed as interest in wearable devices. Especially, carbon nanotubes (CNT) or graphene coating have been used to construct a circuit to induce improvement in flexibility and rigidity. Various technologies have been developed in the surface coating of conductive materials, which are key to the manufacture of flexible electronic devices. Surface coating products with 3D coating and micro-patterns have been proposed through electrospinning, electrification, and 3D printing technologies. As a result of this advanced surface coating technology, there is a growing interest in manufacturing gradient conductive surfaces. Gradient surfaces have the advantage that they are adapted to apply a gentle change or to inspect optimum conditions in a particular region by imparting continuously changing properties. In this study, we propose a manufacturing technique to produce a continuous gradient conductive surface by combining a partial stretching of elastomer and a conductive material coating, and introduce experimental results to confirm its performance.

• Structural Engineering and Mechanics
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• 제76권5호
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• pp.653-661
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• 2020

The paper presents a study regarding rubber compressibility behavior. The objective is to analyze the effect of compression degree of rubber on its mechanical properties and propose a new methodology based on reverse engineering to predict compressibility degree based on uniaxial stretching test and Finite Element Analysis (FEA). In general, rubbers are considered to be almost incompressible and Poisson's ratio is close to 0.5. Since this property is intimately related to the rubber packing density, little changes in Poisson's ratio can lead to significant changes regarding mechanical behavior. The deviatory hyperelastic constants were obtained through experimental data fitting by least squares method for the most relevant constitutive models implemented in commercial software Abaqus, such as: Neo-Hooke, Mooney-Rivlin, Ogden, Yeoh and Arruda-Boyce, whereas the hydrostatic part was determined through an optimization algorithm implemented in the Abaqus environment by Python scripting. The simulation results presented great influence of the Poisson's ratio in the rubber specimen mechanical behavior mainly for high strain levels. A conventional pure volumetric compression test was also carried out in order to compare the results obtained by the proposed methodology.