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991.
Parro V de Diego-Castilla G Rodríguez-Manfredi JA Rivas LA Blanco-López Y Sebastián E Romeral J Compostizo C Herrero PL García-Marín A Moreno-Paz M García-Villadangos M Cruz-Gil P Peinado V Martín-Soler J Pérez-Mercader J Gómez-Elvira J 《Astrobiology》2011,11(1):15-28
The search for unequivocal signs of life on other planetary bodies is one of the major challenges for astrobiology. The failure to detect organic molecules on the surface of Mars by measuring volatile compounds after sample heating, together with the new knowledge of martian soil chemistry, has prompted the astrobiological community to develop new methods and technologies. Based on protein microarray technology, we have designed and built a series of instruments called SOLID (for "Signs Of LIfe Detector") for automatic in situ detection and identification of substances or analytes from liquid and solid samples (soil, sediments, or powder). Here, we present the SOLID3 instrument, which is able to perform both sandwich and competitive immunoassays and consists of two separate functional units: a Sample Preparation Unit (SPU) for 10 different extractions by ultrasonication and a Sample Analysis Unit (SAU) for fluorescent immunoassays. The SAU consists of five different flow cells, with an antibody microarray in each one (2000 spots). It is also equipped with an exclusive optical package and a charge-coupled device (CCD) for fluorescent detection. We demonstrated the performance of SOLID3 in the detection of a broad range of molecular-sized compounds, which range from peptides and proteins to whole cells and spores, with sensitivities at 1-2?ppb (ng?mL?1) for biomolecules and 10? to 103 spores per milliliter. We report its application in the detection of acidophilic microorganisms in the Río Tinto Mars analogue and report the absence of substantial negative effects on the immunoassay in the presence of 50?mM perchlorate (20 times higher than that found at the Phoenix landing site). Our SOLID instrument concept is an excellent option with which to detect biomolecules because it avoids the high-temperature treatments that may destroy organic matter in the presence of martian oxidants. 相似文献
992.
993.
The European Retrievable Carrier (EURECA) is a platform to be launched, deployed and retrieved in low Earth orbit by the Space Shuttle.A newly developed analytical orbit prediction method is described which meets the severe requirements for EURECA's orbit propagation. It is based on an averaging procedure including the Earth's zonal harmonics J2, J3 and J4 and a refined treatment of the air drag perturbation where EURECA's large solar panels are taken into account. Some orbit prediction results are included.In order to offer more flexibility for the Shuttle retrieval of EURECA, it is proposed to execute a part of the rendezvous manoeuvres by EURECA. A corresponding strategy is described. 相似文献
994.
We study the translational–rotational motion of a planet modeled by a viscoelastic sphere in the gravitational fields of an immovable attracting center and a satellite modeled as material points. The satellite and the planet move with respect to their common center of mass that, in turn, moves with respect to the attracting center. The exact system of equations of motion of the considered mechanical system is deduced from the D'Alembert–Lagrange variational principle. The method of separation of motions is applied to the obtained system of equations and an approximate system of ordinary differential equations is deduced which describes the translational–rotational motion of the planet and its satellite, taking into account the perturbations caused by elasticity and dissipation. An analysis of the deformed state of the viscoelastic planet under the action of gravitational forces and forces of inertia is carried out. It is demonstrated that in the steady-state motion, when energy dissipation vanishes, the planet's center of mass and the satellite move along circular orbits with respect to the attracting center, being located on a single line with it. The viscoelastic planet in its steady-state motion is immovable in the orbital frame of reference. It is demonstrated that this steady-state motion is unstable. 相似文献
995.
Bezrukikh V. V. Kotova G. A. Lezhen L. A. Lemaire J. Pierrard V. Venediktov Yu. I. 《Cosmic Research》2003,41(4):392-402
We present the results of temperature and density measurement of plasmaspheric protons under quiet and disturbed conditions in the night and dayside sectors of the plasmasphere obtained with the Auroral Probe/Alpha-3 instrument during September 1996 and January 1997. According to the experimental data, the proton temperature in the night sector of the plasmasphere depends on the level of geomagnetic disturbance: it is found that at night hours the values of temperatures inside the plasmasphere at 2.4 < L < 3.5 decreased considerably after the commencement of a geomagnetic storm. The temperature decrease, as a rule, was accompanied by the formation of a flat plateau on the density distribution n(L) at 2.4 < L < 3.5. The above experimental facts (decreasing proton temperature and formation of a flat part on the n(L) distribution) allow us to conclude that the decrease in the proton temperature in the night sector of the plasmasphere connected with magnetic disturbances is caused by the filling of field tubes (depleted after the commencement of the storm) with colder ionospheric plasma. The proton temperature in the dayside sector of the plasmasphere virtually does not depend on the level of the geomagnetic disturbance. 相似文献
996.
Grajal J. Blazquez R. Lopez-Risueno G. Sanz J.M. Burgos M. Asensio A. 《IEEE transactions on aerospace and electronic systems》2003,39(1):244-258
Detection of simultaneous signals and real-time operation are basic characteristics in broadband electronic warfare (EW) receivers. A digital channelized monobit receiver represents an attempt to achieve both features at the expense of low instantaneous dynamic range. This paper presents a detailed theoretical and experimental analysis, and characterization of the performance of this promising receiver composed of a monobit analog-to-digital converter (ADC) and a filter bank based on a monobit implementation of the discrete Fourier transform (DFT). 相似文献
997.
998.
Yu. T. Tsap A. V. Stepanov L. K. Kashapova I. N. Myagkova A. V. Bogomolov Yu. G. Kopylova T. B. Goldvarg 《Cosmic Research》2016,54(4):285-289
In 2001–2003, the X-ray and microwave observations of ten solar flares of M- and X-classes were carried out by the CORONAS-F orbital station, the RSTN Sun service, and Nobeyama radio polarimeters. Based on these observations, a correlation analysis of time profiles of nonthermal radiation was performed. On average, hard X-ray radiation outstrips the microwave radiation in 9 events, i.e., time delays are positive. The appearance of negative delays is associated with effective scattering of accelerated electrons in pitch angles, where the length of the free path of a particle is less than the half-length of a flare loop. The additional indications are obtained in favor of the need to account for the effect of magnetic mirrors on the dynamics of energetic particles in the coronal arches. 相似文献
999.
The results of analyzing the reliability of six turbulence models are presented as applied to calculations of flows in the asymmetric plane diffuser. The influence of grid parameters upon the calculation results is studied and the accuracy of flow separation and reattachment points prediction is determined. Also carried out is the comparison of processor time spent for calculations with the aid of each model. 相似文献
1000.
C. S. Fish C. M. Swenson G. Crowley A. Barjatya T. Neilsen J. Gunther I. Azeem M. Pilinski R. Wilder D. Allen M. Anderson B. Bingham K. Bradford S. Burr R. Burt B. Byers J. Cook K. Davis C. Frazier S. Grover G. Hansen S. Jensen R. LeBaron J. Martineau J. Miller J. Nelsen W. Nelson P. Patterson E. Stromberg J. Tran S. Wassom C. Weston M. Whiteley Q. Young J. Petersen S. Schaire C. R. Davis M. Bokaie R. Fullmer R. Baktur J. Sojka M. Cousins 《Space Science Reviews》2014,181(1-4):61-120
Funded by the NSF CubeSat and NASA ELaNa programs, the Dynamic Ionosphere CubeSat Experiment (DICE) mission consists of two 1.5U CubeSats which were launched into an eccentric low Earth orbit on October 28, 2011. Each identical spacecraft carries two Langmuir probes to measure ionospheric in-situ plasma densities, electric field probes to measure in-situ DC and AC electric fields, and a science grade magnetometer to measure in-situ DC and AC magnetic fields. Given the tight integration of these multiple sensors with the CubeSat platforms, each of the DICE spacecraft is effectively a “sensor-sat” capable of comprehensive ionospheric diagnostics. The use of two identical sensor-sats at slightly different orbiting velocities in nearly identical orbits permits the de-convolution of spatial and temporal ambiguities in the observations of the ionosphere from a moving platform. In addition to demonstrating nanosat-based constellation science, the DICE mission is advancing a number of groundbreaking CubeSat technologies including miniaturized mechanisms and high-speed downlink communications. 相似文献