• 대한인간공학회지
• /
• 제28권4호
• /
• pp.161-166
• /
• 2009

Although the entrance of house has been identified as a hotspot for older adults' fall accidents, there was not any lift chair to prevent older adults' accidents. In this study, a lift chair was developed to reduce fall accidents that can occur when older adults put on or take off their shoes in the entrance. In order to develop the product, we considered two aspects. Firstly, we considered older adults' anthropometric data to determine the design specification of the product. Also we considered the environmental characteristics of space using the product. In order to overcome the limited spatial freedom and use the entrance space effectively, we took a simplified and folding type for the product.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2000년도 추계학술대회 논문집
• /
• pp.299-302
• /
• 2000

RTD temperature sensor is a thermoresistor which uses the liner dependence of the resistance of the sensing material on the temperature, and has good stability and sensibility, so it can be used in highly precise temperature measurement. In this study RTD sensor was fabricated using Pt thin film. The Pt thin film was deposited on alumina using DC-Sputter, and annealed with various temperature. Through the experiments of XRD, AFM, 4-point probe, the surface structure of the thin film with annealing conditions and their effects on the electrical resistance were investigated. RTD with serpentine pattern was fabricated using Lift-off and resistance-temperature characteristics were studied.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 제26회 KOSCO SYMPOSIUM 논문집
• /
• pp.65-73
• /
• 2003

An experimental study on flame lift-off characteristics of propane jet flame highly diluted with nitrogen has been conducted introducing acoustic forcing with a tube resonant frequency. A flame stability curve is attained according to forcing strength and nozzle exit velocity for $N_2$ diluted flames. Flame lift-off behavior with forcing strength and nozzle exit velocity is globally categorized into three; a well premixed behavior caused by a collapsible mixing for large forcing strength, a coexistent behavior of well-premixed and edge flames interacting with well-organized inner fuel vortices for moderate forcing strengths, and edge flame behavior for small forcing strengths. Special focus is concentrated on the coexistent behavior of the flame base in lifted flame since this may give a hint to a possibility which the flame base behaves like a well-mixed premixed flame in highly turbulent lifted flames. It is also shown that the acoustic forcing to self-pulsating laminar lifted flame affects flame lift-off behavior considerably which is closely related to downstream flow velocity, mixture strength, effective fuel Lewis number, and flame stretch.

• 한국전산유체공학회지
• /
• 제16권1호
• /
• pp.83-89
• /
• 2011

Laminar flow over a cube near a plane wall is numerically investigated in order to understand the effects of the cube-wall gap on the flow characteristics as well as the drag and lift coefficients. The main focus is placed on the three-dimensional vortical structures and its relation to the lift force applied on the cube. Numerical simulations are performed for the Reynolds numbers between 100 and 300, covering several different flow regimes. Without a wall nearby, the flow at Re=100 is planar symmetric with no vortical structure in the wake. However, when the wall is located close to the cube, a pair of streamwise vortices is induced behind the cube. At Re=250, the wall strengthens the existing streamwise vortices and elongates them in the streamwise direction. As a result, the lift coefficients at Re=100 and 250 increase as the cube-wall gap decreases. On the other hand, without a wall, vortex shedding takes place at Re=300 in the form of a hairpin vortex whose strength changes in time. The head of hairpin vortex or loop vortex, which is closely related to the lift force, seems to disappear due to the nearby wall. Therefore, unlike at Re=100 and 250, the lift coefficient tends to decrease more or less as the cube approaches the wall.

• 한국농공학회논문집
• /
• 제53권3호
• /
• pp.35-41
• /
• 2011

A model test is carried out to investigate the vibration of truss type lift gate in the four major rivers project. The gate model scaled with the ratio of 1 : 25 is made of acryl panel dimensioned 1.6 m in width, 0.28 m in height in the concrete test flume. Firstly natural frequencies of the model gate are measured and the results are compared with the numerical results in order to verify the model. The amplitudes of the vibration are measured under the different gate opening and water level conditions. The results are analyzed to study the characteristics of the gate vibration according to the small gate opening, the large gate opening and the overflow conditions. These test results presents a basic data for the guide manuals of gate management and a design method to reduce the gate vibration of truss type lift gate. Finally, the vibration of truss type lift gate are assessed in comparison with those of formerly tainter gate.

• 한국해양공학회지
• /
• 제13권3B호
• /
• pp.14-21
• /
• 1999

As an effective means to convey crushed materials from seabed to onboard ship and to raise hazardous or abrasive liquids, air-lift pump provides a reliable mechanism due to its simple configuration and easy-to-operate principle. The present study is focused on investigation of related performance by the analysis program based on the gas-liquid two-phase flow in circular pipes. The program covers pump operating in isothermal and vertical two-phase flow with Newtonian liquids. It is summarized as important result that an optimum air mass flow rate exists for the maximum lifted liquid mass flow rate in terms of a given submergence rates. The comparison between riser performance of the conveyed liquid flow rate calculated by the computer program and measured data with large scale air lift pump system constructed in 200 meter depth vertical tank reveals similar distribution.

• 한국분무공학회지
• /
• 제18권2호
• /
• pp.100-105
• /
• 2013

While variable valve actuation or variable valve lift (VVL) is used increasingly in spark ignition (SI) engines to improve the volumetric efficiency or to reduce the pumping losses, it is necessary to understand the impact of variable valve lift and timing on the in-cylinder gas motions and mixing processes. In this paper, characteristics of the in-cylinder flow and fuel distribution for various valve lifts (4, 6, 8, 10 mm) were simulated in a GDI engine. It is expected that the investigation will be helpful in understanding and improving GDI combustion when a VVL system is used. The CFD results showed that a increased valve lift could significantly enhance the mixture and in-cylinder tumble motion because of the accelerated air flow. Also, it can be found that the fuel distribution is more affected by earlier injection (during intake process) than that of later injection (end of compression). These may contribute to an improvement in the air-fuel mixing but also to an optimization of intake and exhaust system.

• 한국전산유체공학회지
• /
• 제18권3호
• /
• pp.42-50
• /
• 2013

The supersonic airplane with flapped biplane, Busemann biplane equipped flap, is superior to drag and noise reduction due to wave cancelation effect between upper and lower airfoils. In this study, it is numerically calculated and analyzed the lift, drag and lift to drag ratio of flapped biplane with respect to various the length and angle of the flap. Euler solver of EDISON CFD, web based computational fluid dynamic solver for the purpose of education, is employed. Depending on the length of the flap, lift and drag increase linearly, and there exists the optimum flap angle which maximize the lift-to-drag ratio at the freestream mach 2.0 on-design condition. The predictable relational expression is driven as liner equation. As a results of comparison with drag of flapped biplane, Busemann biplane, and diamond airfoil with the same lift, the drag of flapped biplane is 88.76% lower than that of the Busemann biplane and 70.67% lower than that of the diamond airfoil. In addition, the change of pressure is compared to confirm the noise reduction effect of flapped biplane at h/c=5 of lower airfoil. The shock strength of flapped biplane is smaller than that of other airfoils.

• Archives of Plastic Surgery
• /
• 제42권5호
• /
• pp.521-531
• /
• 2015

Facial rejuvenation procedures can be roughly divided into face lift surgery and nonoperative, less invasive procedures, such as fat grafts, fillers, botulinum toxin injections, thread lifts, or laserbrasion. Face lift surgery or rhytidectomy is the procedure most directly associated with rejuvenation, due to its fundamental ability to restore the anatomical changes caused by aging. Various methods of face lift surgery have been developed over the last hundred years, thanks to advances in the understanding of facial anatomy and the mechanisms of aging, as well as the dedication of innovative surgeons. However, no generally applicable standard method exists, because the condition of each patient is different, and each operative method has advantages and disadvantages. Specific characteristics of the skin of Asians and their skeletal anatomy should be considered when determining the operative method to be used on Asian patients. Plastic surgeons should improve their ability to analyze the original aesthetic properties and problem areas of each patient, drawing on scientific knowledge about the aging process, and they should develop the skills necessary to perform various rejuvenative techniques. In the present article, we reviewed various face lift procedures and the current methods of modified double plane face lift, based on our clinical experience of over 30 years.

• 정보저장시스템학회논문집
• /
• 제5권2호
• /
• pp.70-75
• /
• 2009

Most hard disk drives uses load/unload technology because of benefits as like an increased areal density, a reduced power consumption and an improved shock resistance. However, ramp tilt induced by ramp manufacture and assembly causes mechanical problems such as unload fail in case of exceeding ramp tolerance. In this paper, we focus on experimental analysis for unloading characteristics affected by ramp tilt. We repeatedly perform load/unload test as 500,000 cycles for original model and ramp tilt model. This paper shows that it is possible to analyze unload characteristics through measuring scratch and wear of suspension lift-tab, ramp, suspension dimple-flexure and disk. We also identify structural relation between suspension lift-tab and ramp through scratch and wear of suspension lift-tab and ramp. As the result of measurement and analysis, we can investigate decrease of unloading performance in ramp tilt model.