959 research outputs found
COBE nonspinning attitude propagation
The Cosmic Background Explorer (COBE) spacecraft will exhibit complex attitude motion consisting of a spin rate of approximately -0.8 revolution per minute (rpm) about the x-axis and simultaneous precession of the spin axis at a rate of one revolution per orbit (rpo) about the nearly perpendicular spacecraft-to-Sun vector. The effect of the combined spinning and precession is to make accurate attitude propagation difficult and the 1-degree (3 sigma) solution accuracy goal problematic. To improve this situation, an intermediate reference frame is introduced, and the angular velocity divided into two parts. The nonspinning part is that which would be observed if there were no rotation about the X-axis. The spinning part is simply the X-axis component of the angular velocity. The two are propagated independently and combined whenever the complete attitude is needed. This approach is better than the usual one-step method because each of the two angular velocities look nearly constant in their respective reference frames. Since the angular velocities are almost constant, the approximations made in discrete time propagation are more nearly true. To demonstrate the advantages of this nonspinning method, attitude is propagated as outlined above and is then compared with the results of the one-step method. Over the 100-minute COBE orbit, the one-step error grows to several degrees while the nonspinning error remains negligible
Response to Comment on “Characterization of Excess Electrons in Water-Cluster Anions by Quantum Simulations”
In response to the Comment by Neumark and co-workers, we reiterate that the conclusions of the title Report are based on identifiable characteristic trends in several observables with cluster size. The numerical comparison between simulated and experimental vertical detachment energies emphasized in the Comment reflect quantitative limitations of our atomistic model, but, in our opinion, do not undermine these conclusions
Lipoleiomyoma of the Uterus
Lipoleiomyomas are uncommon benign neoplasms of uterus consisting of variable portions of mature lipocytes and smooth muscle cells. These tumours generally occur in asymptomatic obese perimenopausal or menopausal women. In this paper, a case of lipoleiomyoma uteri in a 53-year old menopausal woman is presented.peer-reviewe
Design Of Neural Network Circuit Inside High Speed Camera Using Analog CMOS 0.35 ¼m Technology
Analog VLSI on-chip learning Neural Networks represent a mature technology for a large number of applications involving industrial as well as consumer appliances. This is particularly the case when low power consumption, small size and/or very high speed are required. This approach exploits the computational features of Neural Networks, the implementation efficiency of analog VLSI circuits and the adaptation capabilities of the on-chip learning feedback schema. High-speed video cameras are powerful tools for investigating for instance the biomechanics analysis or the movements of mechanical parts in manufacturing processes. In the past years, the use of CMOS sensors instead of CCDs has enabled the development of high-speed video cameras offering digital outputs , readout flexibility, and lower manufacturing costs. In this paper, we propose a high-speed smart camera based on a CMOS sensor with embedded Analog Neural Network
Hole Transport in Impurity Band and Valence Bands Studied in Moderately Doped GaAs:Mn Single Crystals
We report on simple experiment on temperature-dependent Hall effect
measurements in GaMnAs single crystalline samples with Mn composition estimated
at 0.05-0.3 at.% which is slightly below the onset of ferromagnetism. Impurity
band transport is visible for Mn compositions of ~0.3 at.% as a clear metallic
behaviour. The results show interesting situation that the Metal-Insulator
transition in GaAs:Mn occurs within the impurity band which is separated from
the valence bands for Mn concentrations studied here. We also discuss on the
equilibrium high temperature solubility limit of Mn in GaAs, unknown precisely
in the literature.Comment: 9 pages, 2 figures, Proc. of 35th International School on the Physics
of Semiconducting Compounds, Jaszowiec 2007, Poland, to appear in Acta
Physica Polonica A (2007
Multipole matrix elements of Green function of Laplace equation
Multipole matrix elements of Green function of Laplace equation are
calculated. The multipole matrix elements of Green function in electrostatics
describe potential on a sphere which is produced by a charge distributed on the
surface of a different (possibly overlapping) sphere of the same radius. The
matrix elements are defined by double convolution of two spherical harmonics
with the Green function of Laplace equation. The method we use relies on the
fact that in the Fourier space the double convolution has simple form.
Therefore we calculate the multipole matrix from its Fourier transform. An
important part of our considerations is simplification of the three dimensional
Fourier transformation of general multipole matrix by its rotational symmetry
to the one-dimensional Hankel transformation
Photon Correlation Spectroscopy and Applications
Contains reports on two research projects.National Science Foundation (Grant DMR-84- 18718)Wan-Yuan Company, Beijing, Peoples Republic of China Contrac
- …