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1.
Kawashima Takeshi 《南京航空航天大学学报(英文版)》2018,(1)
To reduce the collision shock and risk of injury to an infant in an in-car crib(or in a child safety bed)during a car crash,it is necessary to limit the force acting on the crib below a certain allowable value.To realize this objective,we propose a semi-active in-car crib system with the joint application of regular and inverted pendulum mechanisms.The crib is supported by arms similar to a pendulum,and the pendulum system itself is supported by arms similar to an inverted pendulum.In addition,the arm acting as a regular pendulum is joined with the arm acting as an inverted pendulum through a linking mechanism for simplicity,and the friction torque of the joint connecting the base and the latter arm is controlled using a brake mechanism,which enables the proposed in-car crib to gradually increase the deceleration of the crib and maintain it at around the target value.This system not only reduces the impulsive force but also transfers the force to the infant′s back using a spin control system,i.e.,the impulse force is made to act perpendicularly on the crib.The spin control system was developed in our previous work.The present work focuses on the acceleration control system.A semi-active control law with acceleration feedback is introduced using the sliding mode control theory.Especially,a feedback system of the crib acceleration relative to the vehicle is proposed for the high-vibrational environment.Further,a control experiment using scale model is conducted to confirm the effectiveness,and some results are reported. 相似文献
2.
Yuzo Suga Yasushi Ninomiya Takeshi Sakai Hajime Nishikawa Sotaro Tanaka Toshiro Sugimura 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1982,2(8):183-188
We first analyzed aerial, satellite and surface photographs of Hiroshima taken in 1939, 1945, 1947, 1972, 1980 and 1982, in time sequence. It is rather difficult to recognize traces of damage caused by the atomic bombing from surface level with the few exceptions such as the Atomic Bomb Memorial Dome. However, the ground surface pattern of central Hiroshima analyzed by LANDSAT MSS data shows similarities to damage caused by the atomic bombing and the distribution of residual radioactivities. 相似文献
3.
The polymerization of amino acids leading to the formation of peptides and proteins is a significant problem for the origin of life. This problem stems from the instability of amino acids and the difficulty of their oligomerization in aqueous environments, such as seafloor hydrothermal systems. We investigated the stability of amino acids and their oligomerization reactions under high-temperature (180-400°C) and high-pressure (1.0-5.5?GPa) conditions, based on the hypothesis that the polymerization of amino acids occurred in marine sediments during diagenesis and metamorphism, at convergent margins on early Earth. Our results show that the amino acids glycine and alanine are stabilized by high pressure. Oligomers up to pentamers were formed, which has never been reported for alanine in the absence of a catalyst. The yields of peptides at a given temperature and reaction time were higher under higher-pressure conditions. Elemental, infrared, and isotopic analyses of the reaction products indicated that deamination is a key degradation process for amino acids and peptides under high-pressure conditions. A possible NH(3)-rich environment in marine sediments on early Earth may have further stabilized amino acids and peptides by inhibiting their deamination. 相似文献
4.
Akira Kakami Shinji Beppu Muneyuki Maiguma Takeshi Tachibana 《Acta Astronautica》2011,68(7-8):1228-1233
The present paper describes thrust measurement results for an arcjet thruster using Dimethyl ether (DME) as the propellant. DME is an ether compound and can be stored as a liquid due to its relatively low freezing point and preferable vapor pressure. The thruster successfully produced high-voltage mode at DME mass flow rates above 30 mg/s, whereas it yielded low-voltage mode below 30 mg/s. Thrust measurements yielded a thrust of 0.15 N and a specific impulse of 270 s at a mass flow rate of 60 mg/s with a discharge power of 1300 W. The DME arcjet thruster was comparable to a conventional one for thrust and discharge power. 相似文献
5.
Japanese moon lander SELENE-2—Present status in 2009 总被引:1,自引:0,他引:1
Tatsuaki Hashimoto Takeshi Hoshino Satoshi Tanaka Masatsugu Otsuki Hisashi Otake Hitoshi Morimoto 《Acta Astronautica》2011,68(7-8):1386-1391
JAXA is planning exploration missions to the moon, following upon the Kaguya (SELENE) mission., These missions aim to demonstrate some new technologies, observe the moon scientifically, investigate technical, social and political feasibility of utilizing the moon. For the first step of the missions, the phase A study of SELENE-2 has started from the summer of 2007. This mission will demonstrate the effectiveness of several technologies including precision landing, hazard avoidance, surface mobility, and night survival technologies. In situ geological and geophysical observations will be conducted to improve our knowledge on the origin and the evolution of the moon. Investigating the lunar surface conditions and its potential for in situ resource utilization will provide key information for future human exploration missions. This paper presents the current status of the SELENE-2 mission, its objectives, its design, and other important aspects of its development such as international cooperation. 相似文献
6.
S. Ohtsuki N. Iwagami H. Sagawa M. Ueno Y. Kasaba T. Imamura E. Nishihara 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008,41(9):1375-1380
Several ground-based observations of the Venus 1.27-μm O2 airglow were carried out from 2002 to 2005. Spectral image cubes were taken with the Okayama Astrophysical Observatory/infrared imaging spectrometer (superOASIS), the Gunma Astronomical Observatory/Cassegrain Near-Infrared Camera and NASA’s Infrared Telescope Facility/cryogenic echelle spectrograph (CSHELL). The brightest airglow features were found at around the anti-solar point, which is in agreement with previous studies. We derived the rotational temperature distributions on the nightside hemisphere from observed airglow spectra. The temperature shows a weak positive correlation with the airglow intensity. The result indicates the bright region is heated chemically and/or dynamically, and supports the existing scenario for the Venus O2 airglow. That is, the airglow is excited by the descending oxygen transported from the dayside. 相似文献
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8.
Takeshi Imamura Takahiro Iwata Zen-ichi Yamamoto Nanako Mochizuki Yusuke Kono Koji Matsumoto Qinghui Liu Hirotomo Noda Hideo Hanada Koh-ichiro Oyama Alexander Nabatov Yoshifumi Futaana Akinori Saito Hiroki Ando 《Space Science Reviews》2010,154(1-4):305-316
Radio occultation observations of the electron density near the lunar surface were conducted during the SELENE (Kaguya) mission using the Vstar and Rstar sub-satellites. Previous radio occultation measurements conducted in the Soviet lunar missions have indicated the existence of an ionosphere with peak densities of several hundreds of electrons per cubic centimeters above the dayside lunar surface. These densities are difficult to explain theoretically when the removal of plasma by the solar wind is considered, and thus the generation mechanism of the lunar ionosphere is a major issue, with even the validity of previous observations still under debate. The most serious error source in the measurement is the fluctuation of the terrestrial ionosphere which also exists along the ray path. To cope with this difficulty, about 400 observations were conducted using Vstar to enable statistical analysis of the weak signal of the lunar ionosphere. Another method is to utilize Vstar and Rstar with the second one being used to measure the terrestrial ionosphere contribution. The observations will establish the morphology of the lunar ionosphere and will reveal its relationship with various conditions to provide possible clues to the mechanism. 相似文献
9.
Takeshi Sakai Hajime Nishikawa Shigekatsu Endo Sotaro Tanaka Toshiro Sugimura 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1984,4(11):231-234
Observations of satellite images have shown that the snow melting in mountainous area proceeds more repidly in the east-facing slope of the valley than in the west-facing one. The energy for melting snow consists of the total from the atmosphere and from the solar rays. The diurnal variation of the solar energy into the snow in the east-facing slope differs from that in the west-facing slope. This causes the heighest value of the instantaneous energy for melting snow to occur in the west-facing surface. As one of the reasons for the above tendency, the difference of the heighest value to melt snow may be taken into account. 相似文献
10.
Lightning activity in Venus has been a mystery for a long period, although many studies based on observations both by spacecraft and by ground-based telescope have been carried out. This situation may be attributed to the ambiguity of these evidential measurements. In order to conclude this controversial subject, we are developing a new type of lightning detector, LAC (Lightning and Airglow Camera), which will be onboard Planet-C (Venus Climate Orbiter: VCO). Planet-C will be launched in 2010 by JAXA. To distinguish an optical lightning flash from other pulsing noises, high-speed sampling at 50 kHz for each pixel, that enables us to investigate the time variation of each lightning flash phenomenon, is adopted. On the other hand, spatial resolution is not the first priority. For this purpose we developed a new type of APD (avalanche photo diode) array with a format of 8×8. A narrow band interference filter at wavelength of 777.4 nm (OI), which is the expected lightning color based on laboratory discharge experiment, is chosen for lightning measurement. LAC detects lightning flash with an optical intensity of average of Earth’s lightning or less at a distance of 3 Rv. In this paper, firstly we describe the background of the Venus lightning study to locate our spacecraft project, and then introduce the mission details. 相似文献