• Smart Structures and Systems
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• 제16권1호
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• pp.183-194
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• 2015

Shape memory alloy (SMA) helical springs have found a large number of different applications in industries including biomedical devices and actuators. According to the application of SMA springs in different actuators, they are usually under tension and torsion loadings. The ability of SMAs in recovering inelastic strains is due to martensitic phase transformation between austenite and martensite phases. Stress or temperature induced martensite transformation induced of SMAs is a remarkable property which makes SMA springs more superior in comparison with traditional springs. The present paper deals with the simulation of SMA helical spring at room temperature. Three-dimensional phenomenological constitutive model is used to describe superelastic behavior of helical spring. This constitutive model is implemented as a user subroutine through ABAQUS STANDARD (UMAT), and the process of the implementation is presented. Numerical results show that the developed constitutive model provides an appropriate approach to captures the general behavior of SMA helical springs.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.965-966
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• 2010

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.1275-1276
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• 2010

• 한국미생물·생명공학회지
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• 제30권3호
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• pp.287-292
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• 2002

본 연구에서는 경안천 유역에 있는 주유소 오염토양으로부터 대표적인 아조계 염료 congo-red분해능이 우수한 토양 방선균, SMA-2를 분리 선별하고, SMA-2의 배양조건을 최적화하여 2,4-dichlorophenol의 산화에 관여하는 actinomycetes lignin peroxidase(ALiP)의 활성도에 대한 특성을 규명하였다. 기존에 보고된 방선균 유래 ALiP와는 달리, SMA-2유래 ALiP효소는 pH6에서 최고의 활성을 보였으며, 2,4-DCP와 $H_2$$O_2$에 대한 Km값이 각각 0.21mM과 8.5mM로 측정되었다. 또한 최적화된 배지에서 성장한 SMA-2의 배양액은 2,4-dichlorophenol 뿐만 아니라 2-chlorophenol, 2,4,6-trichlorophenol, 2,6-dichlorophenol, phenol, 4-chloropheno떼 대해서도 산화능을 보임으로써, 토양 방선균을 이용한 염화 페놀계 화합물이 포함된 오염 토양의 생복원 가능성을 제시하였다.

• 대한지리학회지
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• 제43권4호
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• pp.580-598
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• 2008

본 두 편의 연속논문은 수도권과 비수도권의 갈등관계를 조절하고 상생전략을 구체적으로 실현하기 위한 수단으로서 수평적 지방재정조정제도 이용방법을 제시한다. 본 논문에서는 먼저 수도권 정책을 둘러싼 선행연구를 비판적으로 검토한다. 수도권의 경제적 이점, 정책방향 및 대도시권의 역할 등을 둘러싸고 양극단의 대립적 견해가 구조적으로 고착화 되고 있지만 상생발전에 대해서는 수사적 제시만 있을 뿐 구체적인 실천수단을 제시하지 못하고 있다. 하나의 대안으로서 한국에서 아직 도입하지 않고 있지만 동일 수준의 지방정부간 재정이전을 동반하는 수평적 지방재정조정제도는 효과적인 상생발전 구현수단이 될 수 있다. 독일, 영국, 프랑스, 스웨덴을 중심으로 외국의 수평적 지방재정조정제도의 기본이념과 논리적 준거 및 조정방법을 살펴보고, 한국 지역정책에 갖는 시사점을 제시한다.

• Biomolecules & Therapeutics
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• 제25권6호
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• pp.648-658
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• 2017

7-O-Succinyl macrolactin A (SMA) exerts several pharmacological effects including anti-bacterial, anti-inflammation, and anti-cancer activities. Recently, SMA has been extensively evaluated as an anti-cancer drug. Thus, the objectives of the present study were to characterise the pharmacokinetics of SMA via both non-compartmental and compartmental analysis in mice, rats, and dogs, and to derive an appropriate first-in-man dose based on allometric scaling of the animal data. The time courses of plasma SMA concentrations after intravenous administration to rats and dogs were analysed retrospectively, as were data collected after intraperitoneal SMA injection in mice. Pharmacokinetic parameters were estimated via both noncompartmental and compartmental analysis, and were correlated with body weight and/or the potential maximum life-span. The clearance and distribution volume of SMA in humans were predicted, and a first-in-man dose proposed. A two-compartment model best described the time courses of SMA plasma concentrations after a saturation elimination process was applied to fit the dataset obtained from rats. Incorporation of the maximum potential life-span during allometric scaling was required to improve the estimation of human clearance. The SMA clearance and the distribution volume in the steady state, in a 70-kg adult male, were estimated to be 30.6 L/h and 19.5 L, respectively. To meet the area under the curve (AUC) required for anti-tumour activity, a dose of 100 mg (~1.5 mg/kg) was finally proposed as the first dose for a 70-kg human. Although toxicological profiles derived from non-clinical studies must be considered before any final decision is made, our work will facilitate clinical studies on SMA.

• Smart Structures and Systems
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• 제31권1호
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• pp.89-100
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• 2023

This paper conducts a parametric study of a new tuned mass damper with pre-strained superelastic SMA helical springs (SMAS-TMD) on the vibration reduction effect. First, a force-displacement relation model of superelastic SMA helical spring is presented based on the multilinear constitutive model of SMA material, and the tension tests of the six SMA springs fabricated are implemented to validate the mechanical model. Then, a dynamic model of a single floor steel frame with the SMAS-TMD damper is set up to simulate the seismic responses of the frame, which are testified by the shaking table tests. The wire diameter, initial coil diameter, number of coils and pre-strain length of SMA springs are extracted to investigate their influences on the seismic response reduction of the frame. The numerical and experimental results show that, under different earthquakes, when the wire diameter, initial coil diameter and number of coils are set to the appropriate values so that the initial elastic stiffness of the SMA spring is between 0.37 and 0.58 times of classic TMD stiffness, the maximum reduction ratios of the proposed damper can reach 40% as the mass ratio is 2.34%. Meanwhile, when the pre-strain length of SMA spring is in a suitable range, the SMAS-TMD damper can also achieve very good vibration reduction performance. The vibration reduction performance of the SMAS-TMD damper is generally equal to or better than that of the classic optimal TMD, and the proposed damper effectively suppresses the detuning phenomena that often occurs in the classic TMD.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.723-726
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• 2002

In the recent years, as the research and the development of micro and precision machinery become active, the interest of micro actuators using SMA(Shape Memory Alloy) has been increased. The dynamic characteristic analysis of SMA is necessary for actuator application and many common researches report the material characteristics of SMA sufficiently. However, the research of dynamic characteristics is very deficient. In this paper, the helical spring is fabricated with NiTi SMA wire of high resistivity The farce, response speed, temperature, and displacement are measured by digital force gauge, infrared thermometer, and laser displacement sensor so that the dynamic characteristics of this SMA actuator is analyzed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1577-1580
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• 2003

In the recent years, as the research and the development of micro and precision machinery become active, the interest of micro actuators using SMA(Shape Memory Alloy) has been increased. The dynamic characteristic analysis of SMA is necessary for actuator application and many common researches report the material characteristics of SMA sufficiently. However, the research on dynamic characteristics is very deficient. In this paper, the helical spring are fabricated with NiTi SMA wire of high resistivity. The force, response speed, temperature, and displacement are measured by digital force gauge, infrared thermometer, and laser displacement sensor so that the dynamic characteristics of this SMA is analyzed. Also, bidirectional actuator was fabricated and experimented for its performance.

• 소성∙가공
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• 제22권8호
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• pp.470-476
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• 2013

The aim of the current study was to predict shape recovery behavior of Ni-Ti shape memory alloy (SMA) wire after loading-unloading and after wire drawing. The superelasticity of SMA was analyzed by a hyper-elastic model for the Mullins effect using ABAQUS. Firstly, tensile tests and loading-unloading tests of the Ni-Ti SMA wire with a diameter 1.0 mm were performed using an MTS servo-hydraulic tester. The parameters for the Mullins effect were computed by ABAQUS based on curve-fitting of the loading-unloading test data. The proposed FE-model predicted the shape recovery of Ni-Ti SMA after wire drawing. Finally, the effectiveness of the model was verified by drawing experiments. The wire drawing experiments using the Ni-Ti SMA were conducted on a drawing machine(1ton, 50mm/s). In order to evaluate the shape recovery of Ni-Ti SMA, the drawn wires are annealed for 30min at $450^{\circ}C$.