• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.1
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• pp.1-12
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• 2022

Wind tunnel test for a small scale electric ducted fan with a 104mm diameter was conducted to analyze the aerodynamic characteristics when it was used as a propulsion system of tilt-propeller UAV. Experimental conditions were derived from flight conditions of a sub-scaled OPPAV. Forces and moments of the ducted fan model were measured by a 6-axis balance and 3-dimensional wake vectors which could induce an aerodynamic influence in the vehicle were measured by 5-hole probes. Thrust and torque on hover and cruise conditions were measured and analyzed to drive out the operating conditions when it was applied in the sub-scaled OPPAV. On transition conditions, thrust keep its value with tilt angle variation below 40° and increase after that. But, sideforce increase constantly until 75°. The maximum axial velocity in the wake on hover and cruise conditions was around 60m/s and tangential velocity was around 12m/s. The position of the maximum axial velocity and vortex center move off the fan rotation center line as the tilt angle increases.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.80-81
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• 2012

Recently, one of the critical issues in the etching processes of the nanoscale devices is to achieve ultra-high aspect ratio contact (UHARC) profile without anomalous behaviors such as sidewall bowing, and twisting profile. To achieve this goal, the fluorocarbon plasmas with major advantage of the sidewall passivation have been used commonly with numerous additives to obtain the ideal etch profiles. However, they still suffer from formidable challenges such as tight limits of sidewall bowing and controlling the randomly distorted features in nanoscale etching profile. Furthermore, the absence of the available plasma simulation tools has made it difficult to develop revolutionary technologies to overcome these process limitations, including novel plasma chemistries, and plasma sources. As an effort to address these issues, we performed a fluorocarbon surface kinetic modeling based on the experimental plasma diagnostic data for silicon dioxide etching process under inductively coupled C4F6/Ar/O2 plasmas. For this work, the SiO2 etch rates were investigated with bulk plasma diagnostics tools such as Langmuir probe, cutoff probe and Quadruple Mass Spectrometer (QMS). The surface chemistries of the etched samples were measured by X-ray Photoelectron Spectrometer. To measure plasma parameters, the self-cleaned RF Langmuir probe was used for polymer deposition environment on the probe tip and double-checked by the cutoff probe which was known to be a precise plasma diagnostic tool for the electron density measurement. In addition, neutral and ion fluxes from bulk plasma were monitored with appearance methods using QMS signal. Based on these experimental data, we proposed a phenomenological, and realistic two-layer surface reaction model of SiO2 etch process under the overlying polymer passivation layer, considering material balance of deposition and etching through steady-state fluorocarbon layer. The predicted surface reaction modeling results showed good agreement with the experimental data. With the above studies of plasma surface reaction, we have developed a 3D topography simulator using the multi-layer level set algorithm and new memory saving technique, which is suitable in 3D UHARC etch simulation. Ballistic transports of neutral and ion species inside feature profile was considered by deterministic and Monte Carlo methods, respectively. In case of ultra-high aspect ratio contact hole etching, it is already well-known that the huge computational burden is required for realistic consideration of these ballistic transports. To address this issue, the related computational codes were efficiently parallelized for GPU (Graphic Processing Unit) computing, so that the total computation time could be improved more than few hundred times compared to the serial version. Finally, the 3D topography simulator was integrated with ballistic transport module and etch reaction model. Realistic etch-profile simulations with consideration of the sidewall polymer passivation layer were demonstrated.

• The Journal of Korean Medicine
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• v.16 no.2 s.30
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• pp.453-489
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• 1995

The research of the phrases related with physiology of stomach and spleen in the contents of Huang Di Nei Jing(黃帝內經) known as the Bible of oriental medicine will make a contribution to a deep understanding of disease of stomach and spleen and a proper clinical diagnosis and treatment of them. In this research of the most appropriate glosses recorded nine kinds of representative medical books including Huang Di Nei Jing Somoon(黃帝內經素問) of Wang Bing(王氷) were picked out: The summaries of the selected contents are as follows: 1. The word 'saliva(涎)' in 'the spleen controls saliva(脾爲涎)' can be viewed as a generic term referring to oral cavity secretion gland as well as the secretion fluid of salivary gland. 2. The phases 'a large reservoir(太倉)', barn organs', 'a reserboir of food stuff', 'a stomach as the market(胃爲之市)', etc mean the function of stomach to receive food(胃主受納). 3. The phase 'generation of five tastes(五味出焉)' means both 'the function of stomach to transform food into chyme(胃主腐熟)' and 'the channelling function of spleen.(脾主運化)' 4. The flowing of the food-Qi(食氣) into stomach brings about spreading Jung(精) into liver and then percolating Jung(精) flow into channel. The channel-Qi(脈氣) flows into lung through channel. As a result, all kinds of channels gather together in lung and Jung(精) is sent into skin and hair. The assembly of Jung(精) with skins and channels moves Qi(氣) into fu-organ and so jung(精) and mental activity(神明) in fu-organ(府) come to be in four organs(四臟). Then if Qi(氣) comes back to power balance unit(權衡) being in the state of equilibrium(權衡以平), the hole of Qi(氣口) comes to determine the matter of life and death through achieving Chun-quan-chi(-寸-關-尺). The above mentioned phrases means the digestion, asorption and transmission of food. When food is taken in stomach, Jung-Qi(精氣) comes to be over flowed upward into spleen, back into lung, finally downward into bladders through water-conduit(水道) controlled by lung. When water- Jung(水精) radiates into whole body with channels of five organs(五臟), both of them fit together with and yin-yang(陰-陽). Therefore, the grasping of the rise and decline of yin-yang(陰C-陽) is necessary to consult patients. The above mentioned phrases is properly viewed to designate the asorption, transmission and excretion of food. 5. Spleen controls flesh(脾之合肉也), the state of spleen is known by human lips, and what this means is that liver plays functions of spread and expansion(肝主疏泄). 6. The phrase 'Jung Jung'((中精)) in 'gallbladder dominates Jung jung(膽主中精)', which in one of the specific expression of 'liver plays functions of spread and expansion(肝主疏泄). 7. It is right that the phase 'The eleven organs in all are determined by gallbladder'(凡十,一臟取決於膽也) is correctly paraphrased as 'only one of ten organs, spleen, is determined by gallbladder'.(凡十,一臟取決於膽也), 8. The small intestine is an organ. which receives the materials digested and sends them out. This means that the function of transforming materials(化物) factually refers to that of separating clearity and blur(泌別淸濁). And it is also thought to have the function of ascending clearity and descending blur(升淸降濁), 9. A large intestine is a transmitting organ(傳導之官) from which a change comes out(變化出焉). the phrase 'change'(變化) in this sentence means both the intake of water and nutrition and the formation procedure of stool through excretion of mucocele.