• 제목/요약/키워드: Earth works

검색결과 265건 처리시간 0.024초

《황제내경(黄帝内经)》 성서적서한문화배경(成书的西汉文化背景) (Cultural Background of the Western Han Dynasty of Huangdi Neijing)

  • 장등본
    • 대한한의학원전학회지
    • /
    • 제26권4호
    • /
    • pp.181-189
    • /
    • 2013
  • Huangdi Neijing was completed during the several decades after Shijiand before Qilue, whose main content draws from the medical achievements of Qin and Han Dynasty, and is deeply influenced by Confucianism, Buddhism and Daoism of Qin and Han Dynasty. What creates the profound impact on its construction of medical theories are the thoughts of this period, such as "Valuing life", "people", "Valuing Yang", "Valuing earth", "the Heaven theory", "the Unity of Man and Nature", and the important works of this period, such as Huai Nan Zi, Chun Qiu Fan Lu, Shiji. Even the astronomy, calendar and medical achievements of this period are the basic material absorbed into the theories of Huangdi Neijing.

Phase Difference Detector for Satellite Tracking Based on Field Experiments of COMETS

  • Ta, Masuhisa;Nakajima, Isao;Juzoji, Hiroshi
    • Journal of Multimedia Information System
    • /
    • 제5권3호
    • /
    • pp.155-162
    • /
    • 2018
  • Nowadays, the tracking technology of Quadrant Detector will become actual by new micro devices. Based on the past filed data of the reception experiment with COMETS satellite, we have studied on new device (AD8302, phase difference detector) was acquired and suspect its abilities. In 1998, we have developed a Quadrant Detector for mobile to track a weak signal from satellite on Ka band of COMETS. The Quadrant Detector is comprised of four dedicated feed components for reception under an environment of Nakagami - Rician fading, and one transmission and reception feed component. We were successful in receiving a 23 GHz beacon signal from ICE transponder of the COMETS and succeeded in tracking the satellite from a moving vehicle at speeds of approximately 10 ~ 20 Km/h on paved roads. In 2018, with new device AD8302, we have verified new QD system and performed a simulation, based on the past filed experiment. This new device shall be improving the tracking abilities from mobile body on the earth to the multimedia satellite.

Digital Magnetic Compass With Smart Correction Function - Recent Experimental Results and Further Works -

  • Yim, Jeong-Bin;Shim, Yeong-Ho;Kim, Chang-Kyeong;Choi, Gi-Young
    • 한국항해항만학회:학술대회논문집
    • /
    • 한국항해항만학회 2004년도 Asia Navigation Conference
    • /
    • pp.29-36
    • /
    • 2004
  • The paper describes recent experimental results on the development of Digital Magnetic Compass (DMC), which can provide smart automatic correction functions to the magnetic interferences. The design methodology of magnetic sensing circuit with ring-core fluxgate sensor is represented. The performance results of the sensing circuits are discussed with error analysis by polynomial regressions. As test results, the sensing circuit filtered only the second harmonic signal that is proportional to the direction of earth's magnetic field, and it leads to the obtainment of bearing information. In addition, the total residual errors of DMC can be analyzed by the adoption of polynomial regressions. It shown that the possibility of high precise DMC, in the future.

  • PDF

위성발사체의 발사궤적 해석 (Launch Trajectory Analysis of a Spacecrafta)

  • 최재원;이장규;이달호
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
    • /
    • pp.614-619
    • /
    • 1988
  • In this paper, an arbitrary mission of a spacecraft from launch to orbit injection is investigated for some launch trajectories. Launch sites are selected arbitrarily from various locations in Korea. For this study, a general purpose simulation program is developed. In this program, the Earth is assumed to be a rotating ellipsold. The launch vehicle is treated as a 3-D, 6-DOF rigid body. The developed program has been evaluated by calibrating it to the 3-stage N-1 rocket developed in Japan and launched at Tanegasima. The simulated trajectory from the first-stage ignition to burnout of third-stage main engine is compared with the previously tested N-1 rocket trajectory in Japan. The result shows that the program works properly. Using the proven program, we have investigated possible launch locations in Korea, namely Marado, Sungsan and Kuryongpo. The problem of polar orbit injection is also examined.

  • PDF

Rockfall analysis using simulation techniques- A practical application to, the Mt. Namsan Gyoungju in Korea

  • Lee, Jong-Yoon;Park, Hyeong-Dong
    • 한국지구물리탐사학회:학술대회논문집
    • /
    • 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
    • /
    • pp.548-552
    • /
    • 2003
  • During the last few decades, the frequency and distribution of rockfalls have been increased in Korea due the development of rock slope in mountain areas. Although the scale of, falling block of rockfall was small, there were some casualties of lives and loss of properties. In order to reduce damage from rockfall, analysis on rock slope indanger of rockfall should be carried out. Thus, the simulation softwares for rockfall behavior analysis have been introduced. In this study, geotechnical investigation and input data for rockfall simulation are described with the comparison among four commercially available rockfall simulation softwares. Finally, rockfall simulation works are described by exmining a case of inaccessible rock-slope of potential rockfall in Korea.

  • PDF

Temperature variation in steel beams subjected to thermal loads

  • Abid, Sallal R.
    • Steel and Composite Structures
    • /
    • 제34권6호
    • /
    • pp.819-835
    • /
    • 2020
  • The effects of atmospheric thermal loads on the response of structural elements that are exposed to open environments have been recognized by research works and design specifications. The main source of atmospheric heat is solar radiation, which dominates the variation of the temperature of air, earth surface and all exposed objects. The temperature distribution along the depth of steel members may differ with the geometry configuration, which means that the different-configuration steel members may suffer different thermally induced strains and stresses. In this research, an experimental steel beam was instrumented with many thermocouples in addition to other sensors. Surface temperatures, air temperature, solar radiation and wind speed measurements were recorded continuously for 21 summer days. Based on a finite element thermal analysis, which was verified using the experimental records, several parametric studies were directed to investigate the effect of the geometrical parameters of AISC standard steel sections on their thermal response. The results showed that the overall size of the beam, its depth and the thickness of its elements are of significant effect on vertical temperature distributions and temperature differences.

수소발생반응에 대한 Pyrites 표면 촉매 성능 예측: 밀도 범함수 이론 계산 (Identification of a Universal Relation between a Thermodynamic Variable and Catalytic Activities of Pyrites toward Hydrogen Evolution Reaction: Density Functional Theory Calculations)

  • 강준희;황지민;한병찬
    • 한국표면공학회:학술대회논문집
    • /
    • 한국표면공학회 2017년도 춘계학술대회 논문집
    • /
    • pp.87.1-87.1
    • /
    • 2017
  • High functional catalyst to efficiently produce clean and earth-abundant renewable fuels plays a key role in securing energy sustainability and environmental protection of our society. Hydrogen has been considered as one of the most promising energy carrier as represented by focused research works on developing catalysts for the hydrogen evolution reaction (HER) from the water hydrolysis over the last several decades. So far, however, the major catalysts are expensive transition metals. Here using first principles density functional theory (DFT) calculations we screen various pyrites for HER by identifying fundamental descriptor governing the catalytic activity. We enable to capture a strong linearity between experimentally measured exchange current density in HER and calculated adsorption energy of hydrogen atom in the pyrites. The correlation implies that there is an underlying design principle tuning the catalytic activity of HER.

  • PDF

RADIOMETRIC CHARACTERISTICS OF KOMPSAT-2 HIGH RESOLUTION IMAGES

  • Chi, Jun-Hwa;Yoon, Jong-Suk;Lee, Kyu-Sung
    • 대한원격탐사학회:학술대회논문집
    • /
    • 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
    • /
    • pp.390-393
    • /
    • 2007
  • KOMPSAT-2, the first Korean high resolution earth observing satellite, continuously acquires high resolution images since July 2006. The quality of satellite images should be geometrically and radiometrically ensured before distribution to users. This study focused on absolute radiometric calibration which is a prerequisite procedure to ensure the radiometric quality of optical satellite images. In this study, we performed reflectance-based vicarious calibration methods on several uniform targets collected through several field campaigns in 2007. The radiative transfer model, MODTRAN, was used to estimate the amount of energy received at the sensor. The energy reached at the sensor are affected by several factors such as reflectance of targets, atmospheric condition, geometry condition between Sun and the sensor, etc. This study proposes the absolute radiometric calibration coefficients of KOMPSAT-2 MSC images combining several types of collected data through field works and tried to compare dynamic range of sensor-detected energy with other commercial high resolution sensors.

  • PDF

황사문제 대책 (Countermeasures on Yellow Dust Problem)

  • 김정수;도덕희
    • 한국가시화정보학회지
    • /
    • 제5권2호
    • /
    • pp.3-8
    • /
    • 2007
  • Yellow dust problem is one of serious environmental problems in East Asia. The earth's abnormal climate changes and rapid industrializations over the mainland China seem to make the matter worse than ever before. In order to solve the yellow dust problem, collaborative works are necessary not only in the fields of meteorology and engineering, and but also through national consistent policies beyond the nations. In this regards, reporting on current policies of our meteorological administrative on the yellow dust problem can be regarded as valuable services for the engineers working in the fields of energy and environments.

Three-axis Attitude Control for Flexible Spacecraft by Lyapunov Approach under Gravity Potential

  • Bang, Hyo-Choong;Lee, Kwang-Hyun;Lim, Hyung-Chul
    • International Journal of Aeronautical and Space Sciences
    • /
    • 제4권1호
    • /
    • pp.99-109
    • /
    • 2003
  • Attitude control law synthesis for the three-axis attitude maneuver of a flexible spacecraft model is presented in this study. The basic idea is motivated by previous works for the extension into a more general case. The new case includes gravitational gradient torque which has significant effect on a wide range of low earth orbit missions. As the first step, the fully nonlinear dynamic equations of motion are derived including gravitational gradient. The control law design based upon the Lyapunov approach is attempted. The Lyapunov function consists of a weighted combination of system kinetic and potential energy. Then, a set of stabilizing control law is derived from the basic Lyapunov stability theory. The new control law is therefore in a general form partially validating the previous work in some sense.