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871.
Wagener T.J. Demma N. Kmetec J.D. Kubo T.S. 《Aerospace and Electronic Systems Magazine, IEEE》1995,10(2):23-28
A flight test of a diode-pumped solid-state 2 μm Doppler Light Detection And Ranging (LIDAR) system was conducted on-board the NASA Ames DC-8 Airborne Laboratory. This was the first ever airborne demonstration of a 2 μm diode-pumped solid-state Doppler LIDAR. The LIDAR performance was verified by comparing the true-airspeed (TAS) estimate with that found using the pneumatic air data system; excellent agreement was found. The capabilities of this pulsed 2 μm Doppler LIDAR system include high bandwidth air data determination without the need for extensive forebody calibration, remote wind profiling as far as several kilometers away from the aircraft, eye-safe laser transmission at 2 μm, and diode-pumped solid-state design for compact construction and reliable performance 相似文献
872.
H. Tanabe S. Isobe H. Akiyama Y. Koma T. Okabe J. Nishimura T. Maihara K. Mizutani J. Soegijo T.E. Hariadi S. Indrawan S. Slamet P. Anondo T. Tatang S. Agus W. Mulyana V.R. Suroto 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1985,5(1):69-72
A balloon observation of the total solar eclipse on 11 June 1983 was carried out as a cooperative work between Japanese and Indonesian teams. The observation was a photo-polarimetry of the F corona in both visual and near-infrared regions.The balloon of 15,000-m3 with a payload of 150-kg was launched at 7h13m on 11 June from Watukosek Balloon Base in East Java. Observation at an altitude of 30.5-km was successfully made during the totality (11h28~32m) at a position of ~40-km east-south-east from Jogjakarta.As a preliminary result, an excess in infrared brightness has been found near the position of 3.8R⊙ west from the sun, which may be due to thermal emission from a high-temperature dust cloud located around the sun. 相似文献
873.
A.D. Schwope G. Lamer D. Burke M. Elvis M.G. Watson M.P. Schulze G. Szokoly T. Urrutia 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2004,34(12):2604-2609
We describe the initial results of a programme to detect and identify extended X-ray sources found serendipitously in XMM-Newton observations. We have analyzed 186 EPIC-PN images at high galactic latitude with a limiting flux of 1 × 10−14 erg cm−2 s−1 and found 62 cluster candidates. Thanks to the enhanced sensitivity of the XMM-Newton telescopes, the new clusters found in this pilot study are on the average fainter, more compact, and more distant than those found in previous X-ray surveys. At our survey limit the surface density of clusters is about 5 deg−2. We also present the first results of an optical follow-up programme aiming at the redshift measurement of a large sample of clusters. The results of this pilot study give a first glimpse on the potential of serendipitous cluster science with XMM-Newton based on real data. The largest, yet to be fulfilled promise is the identification of a large number of high-redshift clusters for cosmological studies up to z = 1 or 1.5. 相似文献
874.
Based on a large number of measurements of the magnetic field and energetic particles onboard the CRRES satellite and on ground-based measurements we describe the fine structure of the first several minutes of the expansion activation of a substorm. The main result is that we have found a fast enhancement of the flux of energetic ions immediately before the beginning of substorm dipolization of the magnetic field. This effect was not known earlier, and the enhancement is invisible from the ground during auroras. We suggest that the appearance of an excess flux of energetic ions has a triggering effect on the local expansion activation of a substorm. The model of a current meander is put forward, which explains the generation of an inductance electric field, current wedge, and other effects of the explosive onset of a substorm. 相似文献
875.
The atmosphere, acting like a lens, causes a small loss in radarsignal strength [1]. Unlike atmospheric absorption [2], the lenseffect loss is different for distributed targets versus point targets.For a distributed target uniformly filling the radar beam, the lens effect loss (in decibels) is one-half the lens-effect loss for point targets. 相似文献
876.
R Woodhouse M Heeb W Berry T Hoshizaki M Wood 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1994,14(11):199-202
Remote non-contact reflection spectroscopy is examined as a method for detecting stress in Controlled Ecological Life Support System CELSS type crops. Lettuce (Lactuca [correction of Latuca] Sativa L. cv. Waldmans Green) and wheat (Triticum Aestivum L. cv. Yecora Rojo) were grown hydroponically. Copper and zinc treatments provided toxic conditions. Nitrogen, phosphorous, and potassium treatments were used for deficiency conditions. Water stress was also induced in test plants. Reflectance spectra were obtained in the visible and near infrared (400nm to 2600nm) wavebands. Numerous effects of stress conditions can be observed in the collected spectra and this technique appears to have promise as a remote monitor of plant health, but significant research remains to be conducted to realize the promise. 相似文献
877.
I.M. Golinskaya A.B. Diachkov V.G. Kurt T.A. Miziakina A.S. Smirnov V.M. Shamolin E.Yu. Shafer E.K. Sheffer 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1984,3(10-12)
This paper describes the X-ray instrumentation, its capabilities and preliminary results which have been obtained for first two months operation. 相似文献
878.
Pattipati K.R. Kurien T. Lee R.-T. Luh P.B. 《IEEE transactions on aerospace and electronic systems》1990,26(5):774-791
The problem of mapping the tasks of a multitarget tracking algorithm onto parallel computing architectures to maximize speedup is considered. An asymptotically optimal mapping algorithm is developed and applied to study the effects of task granularity and processor architectures on the speedup. From the simulation results, it is concluded that task granularity and the parallelization of clustering and global hypotheses formation stages of the tracking algorithm are major determinants of speedup 相似文献
879.
A major source of transonic and supersonic wind-tunnel test data uncertainty are angle-of-attack-measurement errors caused by unknown sting and balance deflections under load. Since dynamic loads in pressurized or cryogenic wind tunnels generally exceed those in conventional low-speed atmospheric wind tunnels, the need to account for these distortions during model testing is even more acute. A novel laser-based instrument for the in-situ measurement of wind-tunnel-model angle of attack that enables continuous, time-dependent measurements to be made without signal dropout is described. Proof-of-concept experiments, along with the results of recent measurements conducted at the NASA Ames 9-ft×7-ft supersonic wind tunnel, are presented. Experiments were also conducted to determine the reliable range, sensitivity, and long-term stability of the instrument. The results show that 0.01° sensitivity can be achieved and that optical and detector packaging requirements are less stringent than those for current tilt-sensor or accelerometer model installations 相似文献
880.
J.G. Luhmann R.C. Elphic C.T. Russell L.H. Brace R.E. Hartle 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1982,2(10):17-21
Theoretical models of the ionosphere of Venus have been constructed in the past without due consideration of the fact that the ionosphere is sometimes magnetized. This paper examines some differences between the magnetized and unmagnetized dayside Venus ionosphere using the Pioneer Venus Orbiter Langmuir probe and magnetometer data. Particular attention is given to the evaluation of the altitude profiles of the thermal electron heating and comparison of the magnitude of the magnetic force(¯vׯB) ׯB with other forces in the ionosphere. Several examples illustrate how heating profiles are different in the magnetized ionosphere with effective heating below ~200 km altitude reduced by orders of magnitude compared to the field-free ionosphere. The force associated with the magnetic field is comparable to other forces in the magnetized ionosphere. The measured plasma density, electron temperature and magnetic field thus suggest that large-scale magnetic fields should be included in future ionosphere models. 相似文献