1,951 research outputs found
Fast Switching Ferroelectric Materials for Accelerator Applications
Fast switching (< 10 nsec) measurement results on the recently developed
BST(M) (barium strontium titanium oxide composition with magnesium-based
additions) ferroelectric materials are presented. These materials can be used
as the basis for new advanced technology components suitable for high-gradient
accelerators. A ferroelectric ceramic has an electric field-dependent
dielectric permittivity that can be altered by applying a bias voltage.
Ferroelectric materials offer significant benefits for linear collider
applications, in particular, for switching and control elements where a very
short response time of <10 nsec is required. The measurement results presented
here show that the new BST(M) ceramic exhibits a high tunability factor: a bias
field of 40-50 kV/cm reduces the permittivity by a factor of 1.3-1.5. The
recently developed technology of gold biasing contact deposition on large
diameter (110 cm) thin wall ferroelectric rings allowed ~few nsec switching
times in witness sample experiments. The ferroelectric rings can be used at
high pulsed power (tens of megawatts) for X-band components as well as at high
average power in the range of a few kilowatts for the L-band phase-shifter,
under development for optimization of the ILC rf coupling. Accelerator
applications include fast active X-band and Ka-band high-power ferroelectric
switches, high-power X-band and L-band phase shifters, and tunable
dielectric-loaded accelerating structures.Comment: 7 pages, 6 figures, submitted to Proceedings of 2006 Advanced
Accelerator Concepts Worksho
Influence of Filler Metals in Welding Wires on the Phase and Chemical Composition of Weld Metal
The influence of filler metals used in welding wires on the phase and chemical composition of the metal, which is surfaced to mining equipment exposed to abrasive wear, has been investigated. Under a laboratory environment, samples of Mo-V-B and Cr-Mn-Mo-V wires were made. The performed experiments have revealed that fillers of the Cr-Mn-Mo-V system used in powder wire show better wear resistance of the weld metal than that of the Mn-Mo-V-B system; the absence of boron, which promotes grain refinement in the Mn-Mo-V-B system, significantly reduces wear resistance; the Mn-Mo-V-B weld metal has a finer structure than the Cr-Mn-Mo-V weld metal
HEAT PUMP APPLICATION IN HEAT DELIVERY SYSTEM
The article provides examples of the use of heat pump installations for heating industrial premises. Recommendations on the location of sources of low-potential thermal energy (LPTE) are formulated. Developed a plan for further work.В статье приведены примеры использования теплонасосных установок для отопления производственных помещений. Сформулированы рекомендации по выбору места расположения источников низкопотенциальной тепловой энергии (НПТ). Разработан план дальнейшей работы
On Quality of a Weld Bead Using Power Wire 35v9h3sf
The effect of introducing carbon-fluorine containing additives and nickel to flux-cored wire 35V9H3SF on its structure, micro hardness of martensite, hardness and wear rate of a welded layer has been investigated. It has been proven that carbon-fluorine additions to a powder mixture increase the hardness of the deposited layer and its wearing strength. Nickel adding increases the hardness of both martensite and the deposited layer, and reduces abrasion wear. Introducing carbon-fluorine containing additives to the powder mixture can reduce the pore formation and lower the level of impurity with nonmetallic inclusions; and nickel adding can lead to austenite having a finer grain size
p-Adic Models of Ultrametric Diffusion Constrained by Hierarchical Energy Landscapes
We demonstrate that p-adic analysis is a natural basis for the construction
of a wide variety of the ultrametric diffusion models constrained by
hierarchical energy landscapes. A general analytical description in terms of
p-adic analysis is given for a class of models. Two exactly solvable examples,
i.e. the ultrametric diffusion constraned by the linear energy landscape and
the ultrametric diffusion with reaction sink, are considered. We show that such
models can be applied to both the relaxation in complex systems and the rate
processes coupled to rearrangenment of the complex surrounding.Comment: 14 pages, 6 eps figures, LaTeX 2.0
A p-Adic Model of DNA Sequence and Genetic Code
Using basic properties of p-adic numbers, we consider a simple new approach
to describe main aspects of DNA sequence and genetic code. Central role in our
investigation plays an ultrametric p-adic information space which basic
elements are nucleotides, codons and genes. We show that a 5-adic model is
appropriate for DNA sequence. This 5-adic model, combined with 2-adic distance,
is also suitable for genetic code and for a more advanced employment in
genomics. We find that genetic code degeneracy is related to the p-adic
distance between codons.Comment: 13 pages, 2 table
Electrical resistance associated with the scattering of optically oriented electrons in n-GaAs
In a bulk GaAs crystal, an unusual magnetoresistance effect, which takes
place when a spin-polarized current flows through the sample, was detected.
Under conditions of optical pumping of electron spins, an external magnetic
field directed along the electric current and perpendicular to the oriented
spins decreases the resistance of the material. The phenomenon is due to the
spin-dependent scattering of electrons by neutral donors. It was found that the
sign of the magnetoresistance does not depend on the sign of the exciting light
circular polarization, the effect is even with respect to the sign of the spin
polarization of the carriers, which indicates a correlation between the spins
of optically oriented free electrons and electrons localized on donors.Comment: 9 pages, 4 figure
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