• Title/Summary/Keyword: H-plane

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Dynamic Response and Control of Airship with Gust (외란이 작용하는 비행선의 동적 반응 및 제어)

  • Woo, G.A.;Park, I.H.;Oh, S.J.;Cho, K.R.
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.30 no.6
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    • pp.69-77
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    • 2002
  • To acquire the dynamic response and design the controller of the airship, the longitudinal motion of the airship with respect to the vertical gust, which is the nonlinear system, was studied. The effects of the apparent mass and moment of the airship delay the dynamic response and the settling time, which are slower than those of conventional airplanes. The current object of the airship is designed to cruise at 500~1000m altitude. At that height, the atmospheric conditions are generally unstable by wind gust. In this paper, it has been studied for the case of vertical gust, since the apparent mass effects are dominant in has been studied for the case of vertical gust, since the apparent mass effects are dominant in that plane. In addition to the study of the dynamic responses of the airship, the controller was designed using the PID-controller. When the gust was applied, airship responses were recovered of equilibrium states. However, it takes too ling time for recovery and the speed of airship is reduced. So, the aim in this paper was to fasten the recovery speed and to get back the cruising velocity. The control parameters were determined from the stability mode analysis, and the control inputs were the thrust and the elevator deflection angle.

Effects of Yanghyuljanggeungunbo-tang(Yangxuezhuangjinjianbu-tang) and Electrical Acupuncture on the Spinal Nerve Injury and the Motor Function (양혈장근건보탕(養血壯筋健步湯)과 전침의 병용치료가 손상된 척수신경 및 운동기능에 미치는 영향)

  • Sul, Jae-Uk;Chu, Min-Kyu;Kim, Sun-Jong;Choi, Jin-Bong;Shin, Mi-Suk;Kim, Soo-Ik
    • Journal of Korean Medicine Rehabilitation
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    • v.19 no.2
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    • pp.1-25
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    • 2009
  • Objectives : The purpose of this study was to investigate the effects of Yanghyuljanggeungunbo-tang(Yangxuezhuangjinjianbu-tang, YGKT) and electrical acupuncture treatment in spinal cord injury(SCI)-induced rats. Methods : The subjects were divided into 5 groups ; Normal, Control-no treatment after SCI, Experimental I(Exp. I)-taken with YGKT 500 mg/kg $0.5m{\ell}$ daily after SCI. Experimental II(Exp. II)-taken with electrical acupuncture after SCI and Experimental III(Exp. III)-taken with YGKT 500 mg/kg $0.5m{\ell}$ and electrical acupuncture after SCI. After each operation, the present author observed cytological changes, the motor behavior recovery and nerve regeneration by analysis of the motor behavior tests, EMG, hematological(AST, ALT, WBC), histological and immunological changes. Rats were tested by Motor behavior test at 1st, 3rd, 7th, 14th and 21st day. Results : 1. All the experimental groups were improved compared with control group in the motor behavior tests including Tarlov test, Basso-Beattle-Bresnahan locomotor rating scale, modified inclined plane test, open field test, grid walk test and narrow beam test. Especially Exp. III was significantly improved among other groups. 2. In EMG test, H and M wave were significantly increased in Exp. III. 3. All the experimental groups were significantly decreased compared with control group in AST, ALT and WBC. 4. NGF, BDNF and Trk B of spinal cord gray matter in all the experimental groups were increased compared with control group. Especially, Exp. III was more effective. 5. In histological observations, muscle contraction and denaturation of gastrocnemius muscle of all the experimental groups were inhibited. Especially, those of Exp. III was more effective. On the observations of liver and kidney, cell atrophy and apoptosis of all the experimental groups were decreased compared with control group. Especially, those of Exp. III was more effective. Conclusions : It can be suggested that YGKT and electrical acupuncture may improve motor behavior, EMG, hematological, histological and immunological findings in SCI-induced rats. Especially, combination of these two treatments will be somewhat better in spinal nerve recovery and motor function improvement.

Effects of Yanghyuljanggeungunbo-tang(Yangxuezhuangjinjianbu-tang) and Cervi Cornu Parvum Pharmaco-Acupuncture on the Motor Function Recovery and Nerve Regeneration in Rats Induced Spinal Cord Injury (양혈장근건보탕(養血壯筋健步湯)과 녹용약침(鹿茸藥鍼)이 척수손상 유발 흰쥐의 운동기능 회복 및 신경재생에 미치는 영향)

  • Park, Ji-Yong;Sul, Jae-Uk;Kim, Sun-Jong;Choi, Jin-Bong;Shin, Mi-Suk
    • Journal of Korean Medicine Rehabilitation
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    • v.19 no.2
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    • pp.27-49
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    • 2009
  • Objectives : The purpose of this study was to investigate the effects of Yanghyuljanggeungunbo-tang(Yangxuezhuangjinjianbu-tang) and Cervi Cornu Parvum pharmaco-acupuncture in Spinal Cord Injury(SCI)-induced rats. Methods : The subjects were divided into 5 groups ; Normal, Control no treatment after SCI, Experimental I taken with Yanghyuljanggeungunbo-tang (Yangxuezhuangjinjianbu-tang) 500 mg/kg $0.5m{\ell}$ daily after inducing SCI. Experimental II taken with Cervi Cornu Parvum pharmaco-acupuncture at Taegye(KI3) and $Yangnungch{\acute{o}}n$(GB34) after inducing SCI and Experimental III taken with Yanghyuljanggeungunbo-tang(Yangxuezhuangjinjianbu-tang) 500 mg/kg $0.5m{\ell}$ and Cervi Cornu Parvum pharmaco-acupuncture at KI3 and GB34 to SCI-induced rats. After each operation, the present author observed the motor behavior recovery and nerve regeneration by analysis of the motor behavior tests, EMG, hematological(AST, ALT, WBC), histological and immunological changes. Rats were tested at modified Tarlov test at the 1st, 2nd, 3rd, 4th day, and Motor behavior test at 1st, 3rd, 7th, 14th, 21st day. Results : Results are as follows. 1. All the experimental groups were improved compared with control group in the motor behavior tests including Tarlov test, Basso-Beattle-Bresnahan locomotor rating scale, modified inclined plane test, open field test, grid walk test and narrow beam test. Especially Experimental III was improved significantly among other groups. 2. In EMG test, H wave appeared weak only in Experimental III. And M wave was increased significantly in Experimental III. 3. All the experimental groups were significantly decreased compared with control group in serum AST, serum ALT and serum WBC tests. 4. significantly decreased in Tumor Necrosis Factor-${\alpha}$ test compared with the first day of SCI. 5. Muscle contraction and denaturation of all the experimental groups were inhibited in histological observations of gastrocnemius muscle. Especially, those of experimental III was more effective. 6. NGF and BDNF of spinal cord gray matter in all the experimental groups were increased compared with control group. Especially, those of experimental III was more effective. Conclusions : As above, it can be suggested that Yanghyuljanggeungunbo-tang(Yangxuezhuangjinjianbu-tang) and Cervi Cornu Parvum pharmaco-acupuncture may improve motor behavior, EMG, hematological, histological and immunological findings in Spinal Cord Injury(SCI)-induced rats. Especially, effects will be somewhat better in combination of these two treatments.

Software development for the visualization of brain fiber tract by using 24-bit color coding in diffusion tensor image

  • Oh, Jung-Su;Song, In-Chan;Ik hwan Cho;Kim, Jong-Hyo;Chang, Kee-Hyun;Park, Kwang-Suk
    • Proceedings of the KSMRM Conference
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    • 2002.11a
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    • pp.133-133
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    • 2002
  • Purpose: The purpose of paper is to implement software to visualize brain fiber tract using a 24-bit color coding scheme and to test its feasibility. Materials and Methods: MR imaging was performed on GE 1.5 T Signa scanner. For diffusion tensor image, we used a single shot spin-echo EPI sequence with 7 non-colinear pulsed-field gradient directions: (x, y, z):(1,1,0),(-1,1,0),(1,0,1),(-1,0,1),(0,1,1),(0,1,-1) and without diffusion gradient. B-factor was 500 sec/$\textrm{mm}^2$. Acquisition parameters are as follows: TUTE=10000ms/99ms, FOV=240mm, matrix=128${\times}$128, slice thickness/gap=6mm/0mm, total slice number=30. Subjects consisted of 10 normal young volunteers (age:21∼26 yrs, 5 men, 5 women). All DTI images were smoothed with Gaussian kernel with the FWHM of 2 pixels. Color coding schemes for visualization of directional information was as follows. HSV(Hue, Saturation, Value) color system is appropriate for assigning RGB(Red, Green, and Blue) value for every different directions because of its volumetric directional expression. Each of HSV are assigned due to (r,$\theta$,${\Phi}$) in spherical coordinate. HSV calculated by this way can be transformed into RGB color system by general HSV to RGB conversion formula. Symmetry schemes: It is natural to code the antipodal direction to be same color(antipodal symmetry). So even with no symmetry scheme, the antipodal symmetry must be included. With no symmetry scheme, we can assign every different colors for every different orientation.(H =${\Phi}$, S=2$\theta$/$\pi$, V=λw, where λw is anisotropy). But that may assign very discontinuous color even between adjacent yokels. On the other hand, Full symmetry or absolute value scheme includes symmetry for 180$^{\circ}$ rotation about xy-plane of color coordinate (rotational symmetry) and for both hemisphere (mirror symmetry). In absolute value scheme, each of RGB value can be expressed as follows. R=λw|Vx|, G=λw|Vy|, B=λw|Vz|, where (Vx, Vy, Vz) is eigenvector corresponding to the largest eigenvalue of diffusion tensor. With applying full symmetry or absolute value scheme, we can get more continuous color coding at the expense of coding same color for symmetric direction. For better visualization of fiber tract directions, Gamma and brightness correction had done. All of these implementations were done on the IDL 5.4 platform.

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Performance Prediction of a Laser-guide Star Adaptive Optics System for a 1.6 m Telescope

  • Lee, Jun Ho;Lee, Sang Eun;Kong, Young Jun
    • Current Optics and Photonics
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    • v.2 no.3
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    • pp.269-279
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    • 2018
  • We are currently investigating the feasibility of a 1.6 m telescope with a laser-guide star adaptive optics (AO) system. The telescope, if successfully commissioned, would be the first dedicated adaptive optics observatory in South Korea. The 1.6 m telescope is an f/13.6 Cassegrain telescope with a focal length of 21.7 m. This paper first reviews atmospheric seeing conditions measured over a year in 2014~2015 at the Bohyun Observatory, South Korea, which corresponds to an area from 11.6 to 21.6 cm within 95% probability with regard to the Fried parameter of 880 nm at a telescope pupil plane. We then derive principal seeing conditions such as the Fried parameter and Greenwood frequency for eight astronomical spectral bands (V/R/I/J/H/K/L/M centered at 0.55, 0.64, 0.79, 1.22, 1.65, 2.20, 3.55, and $4.77{\mu}m$). Then we propose an AO system with a laser guide star for the 1.6 m telescope based on the seeing conditions. The proposed AO system consists of a fast tip/tilt secondary mirror, a $17{\times}17$ deformable mirror, a $16{\times}16$ Shack-Hartmann sensor, and a sodium laser guide star (589.2 nm). The high order AO system is close-looped with 2 KHz sampling frequency while the tip/tilt mirror is independently close-looped with 63 Hz sampling frequency. The AO system has three operational concepts: 1) bright target observation with its own wavefront sensing, 2) less bright star observation with wavefront sensing from another bright natural guide star (NGS), and 3) faint target observation with tip/tilt sensing from a bright natural guide star and wavefront sensing from a laser guide star. We name these three concepts 'None', 'NGS only', and 'LGS + NGS', respectively. Following a thorough investigation into the error sources of the AO system, we predict the root mean square (RMS) wavefront error of the system and its corresponding Strehl ratio over nine analysis cases over the worst ($2{\sigma}$) seeing conditions. From the analysis, we expect Strehl ratio >0.3 in most seeing conditions with guide stars.

The Electronic Structure and Magnetism of bcc Rh(001) Surface (체심 입방구조 Rh(001) 표면의 전자구조와 자성)

  • Cho, L.H.;Bialek, B.;Lee, J.I.
    • Journal of the Korean Magnetics Society
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    • v.18 no.6
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    • pp.206-210
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    • 2008
  • According to the recent reports the bulk bcc Rh is ferromagnetic with a small difference of energy compared to paramagnetic state. In this study, the electronic structure and magnetism for bcc Rh(001) surface are investigated by means of the all-electron full potential linearized augmented plane wave method within the generalized gradient approximation. It is found that the surface ferromagnetic state is preferable over the paramagnetic one. For unrelaxed system, the magnetic moment of the surface layer, $0.48{\mu}B$, is slightly increased comparing with the bulk value, $0.41{\mu}B$ while the value of the subsurface layer, $0.23{\mu}B$, is much smaller than the bulk value. The total energy and atomic force calculations show that the surface layer is relaxed downward and the subsurface layer moves upward to reduce the layer distance between the surface and subsurface layers by 7.0 %. The relaxation effect leads to weakening the surface magnetic properties. Specifically, the value of the magnetic moment of the surface atom is decreased to $0.36{\mu}B$. Since the spin polarization of the subsurface layer is only $0.14{\mu}B$, it is concluded that the bcc Rh(001) surface is rather weakly ferromagnetic.

A Study on the boiler efficiency with selecting the uppermost burners in the 870MW opposite wall fired boiler (870MW 대향류 보일러에서 최상부층 버너 선택운전에 따른 보일러 효율변화 고찰)

  • Woo, Gwang-Yoon;Kim, Soo-Seok;Park, In-Chan;Ham, Young-Jun;Lee, Eung-Yoon
    • Plant Journal
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    • v.13 no.2
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    • pp.46-51
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    • 2017
  • In this study, the boiler efficiency and the change of boiler combustion state with the burner operation of the uppermost layer of 870MW opposite fired coal boiler were measured. Test results showed that the boiler efficiency was high in the order of the uppermost layer simultaneous operation of the front and rear burners, the front burner, and the rear burner operation. When the front and rear burners were operated simultaneously, the heat absorption rate of water walls in the boiler furnace was uniform at four side, and the temperature deviation of the left and right steam on the convection front surface decreased. As the heat absorption rate of the boiler improved, the loss of boiler exhaust gas decreased and the coal supply amount decreased by 8 tons/hour compared to the operation of the rear burner. This will contribute not only to the reduction of fuel cost but also to the reduction of greenhouse gas emissions.

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Study on the Scale Effect of Viscous Flows around the Ship Stern (선미 점성 유동장에 미치는 척고효과에 관한 연구)

  • Kwak, Y.K.;Min, K.S.;Oh, K.J.;Kang, S.H.
    • Journal of the Society of Naval Architects of Korea
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    • v.34 no.1
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    • pp.1-10
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    • 1997
  • Viscous flow around actual ship is calculated by an use of RANS equations. The propriety of this computing method, usefulness to hull form design and the scale effect which is the effect of viscous flow depending on the scale of ship model are investigated. Reynolds stress is modelled by using k-${\varepsilon}$ turbulence model and the law of wall is applied near the body. Body fitted coordinates are introduced for the treatment of the arbitrary 3-dimensional shape of the ship hull form. The transformed equations in the computational domain are numerically solved by an employment of FVM. In the calculation of pressure, SIMPLE method is adopted and the solution of the discretized equation is obtained by the line-by-line method with the use of TDMA The calculations of two ships, 4410 TEU container carrier and 50,000 DWT class bulk carrier, are performed at model and actual ship scale. The results are compared and discussed with the model test results which are viscous resistance, nominal wake distribution at propeller plane and limiting streamline on the hull surface. They describe the effect of stem form and the scale effect very well. In particular, the calculated nominal wake distribution and limiting streamline are agreed qualitatively with the experiments and the viscous resistance values are estimated within ${\pm}5%$ difference from the resistance tests.

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Cavity-Backed Slot Array Antenna for a Repeater System of a Satellite Digital Multimedia Broadcasting (위성 DMB 중계기용 Cavity-Backed슬롯 배열 안테나)

  • Jung Hee-Chul;Lee Hak-Yong;Jung Byungwoon;Kang Gi-Cho;Park Myun-Joo;Lee Byungje
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.16 no.4 s.95
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    • pp.366-372
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    • 2005
  • This paper presents analysis of a slot array antenna having a low side lobe level and high front-to-back ratio for a repeater system of a satellite DMB(Digital Multimedia Broadcasting) service. Antennas for this repeater system require a high gain and enough isolation to reduce interferences between signals in system. Therefore, it is necessary to suppress a side lobe level and to increase front-to-back ratio. Unlike a structure 134 by lossy microstrip lines, in this work a single cavity-backed slot antenna array using a single waveguide feed is proposed to obtain the reliability for high power handling and high radiation efficiency. The side lobe level and front-to-back ratio are enhanced with tapered array technique and an optimized vertical reflector. The measured side lobe levels in H- and E-plane are under $-33.24\;\cal{dB}$ and $-35.78\;\cal{dB}$, respectively. The front-to-back ratio over $37.84\;\cal{dB}$, and the peak gain of over $17\;\cal{dBi}$ are measured.

The Effects of Treadmill Exercise on the Recovery of Functional Capacity in Spinal Cord Injured Rats (트레드밀 운동이 척수손상 백서의 운동기능 회복에 미치는 효과)

  • Chun, Jin-Sung;Kim, Tae-Youl;Nam, Ki-Won;Kim, Young-Eok;Oh, Myung-Hwa;Kim, Kyoung-Yoon;Kim, Eun-Jung;Lee, Jae-Choon;Jang, Mee-Kyung;Choi, Hyun-Seok;Heo, Myung;Kim, Gye-Yeop
    • The Journal of Korean Physical Therapy
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    • v.19 no.4
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    • pp.15-24
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    • 2007
  • Purpose: This study was designed to investigate the effects of treadmill exercise on functional recovery after rat with experimental SCI. Methods: SCI was induced by the NYU-spinal cord impactor(NYU, USA) dropped a weight of 10 gm after laminectomy. Experimental groups were divided into the Group I (normal), Group II (control) and Group III(treadmill exercise). After 2 days of the operation, 24 rats(group II, III) were trained to walk on treadmill for 21 days twice/day, 15 min/session. After operation, rats were tested at modified Tarlov scale at 1, 2, 3, 4 days with divided into 2 groups, and Motor behavior test(BBB locomotor rating scale, Grid walking test, Narrow beam crossing test, Modified inclined plane test) was examined at 1, 3, 7, 14 and 21 days. Histopathological study were performed at 1. 3, 7, 14 and 21 days by H&E, Luxol Fast Blue staining were same times. Results: After SCI an improvement of motor behavior was shown group II, III. The motor behavior test of group Ill showed considerable improvement until 14 days. Conclusion: These results suggest that treadmill exercise treatment can playa role in facilitating recovery of locomotion following spinal cord injury.

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