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

Chronic Contusion Spinal Cord Injury Impairs Ejaculatory Reflexes in Male Rats: Partial Recovery by Systemic Infusions of Dopamine D3 Receptor Agonist 7OHDPAT

Chronic spinal cord injury (SCI) causes major disruption of ejaculatory function in men. Ejaculation is a reflex and the spinal generator for ejaculatory reflexes in the rat has been located in the lumbosacral spinal cord. The effects of SCI on the rat spinal ejaculation generator and ejaculatory reflexes remain understudied. The first goal of the current study was to establish the effects of chronic SCI on the function of the spinal ejaculation generator. Male rats received a contusion injury of the spinal cord at spinal level T6?T7. Ejaculatory reflexes elicited by electrical stimulation of the dorsal penile nerve (DPN) were evaluated in injured and control rats at 4?6 weeks following SCI. SCI males demonstrated significant reductions in bursting of the bulbocavernosus muscle (BCM), an indicator for expulsion phase of ejaculation, and in seminal vesicle pressure (SVP) increases, an indicator for the emission phase of ejaculation, following DPN stimulation. Thus, contusion SCI resulted in long-term impairment of ejaculatory reflexes. The D3 agonist 7-hydroxy-2-(di-N-propylamino) tetralin (7OHDPAT) facilitates ejaculation in spinal cord intact rats, thus the second goal of the current study was to test whether subcutaneous infusions of 7OHDPAT can facilitate ejaculatory reflexes in rats with chronic SCI. Male rats received a contusion injury at T6?T7 and effects of systemic administration of 7OHDPAT (1?mg/kg) were tested 4?5 weeks following injury. Results showed that 7OHDPAT administration facilitated ejaculatory reflexes in SCI males with or without DPN stimulation, provided that supraspinal inputs to the lumbar cord were severed by transection just prior to evaluating the reflex. Thus, 7OHDPAT administration in SCI males was able to overcome the detrimental effects of SCI on ejaculatory reflexes.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140172/1/neu.2015.4232.pd

Chronic contusion spinal cord injury impairs ejaculatory reflexes in male rats: Partial recovery by systemic infusions of dopamine D3 receptor agonist 7OHDPAT

Chronic spinal cord injury (SCI) causes major disruption of ejaculatory function in men. Ejaculation is a reflex and the spinal generator for ejaculatory reflexes in the rat has been located in the lumbosacral spinal cord. The effects of SCI on the rat spinal ejaculation generator and ejaculatory reflexes remain understudied. The first goal of the current study was to establish the effects of chronic SCI on the function of the spinal ejaculation generator. Male rats received a contusion injury of the spinal cord at spinal level T6-T7. Ejaculatory reflexes elicited by electrical stimulation of the dorsal penile nerve (DPN) were evaluated in injured and control rats at 4-6 weeks following SCI. SCI males demonstrated significant reductions in bursting of the bulbocavernosus muscle (BCM), an indicator for expulsion phase of ejaculation, and in seminal vesicle pressure (SVP) increases, an indicator for the emission phase of ejaculation, following DPN stimulation. Thus, contusion SCI resulted in long-term impairment of ejaculatory reflexes. The D3 agonist 7-hydroxy-2-(di-N-propylamino) tetralin (7OHDPAT) facilitates ejaculation in spinal cord intact rats, thus the second goal of the current study was to test whether subcutaneous infusions of 7OHDPAT can facilitate ejaculatory reflexes in rats with chronic SCI. Male rats received a contusion injury at T6-T7 and effects of systemic administration of 7OHDPAT (1 mg/kg) were tested 4-5 weeks following injury. Results showed that 7OHDPAT administration facilitated ejaculatory reflexes in SCI males with or without DPN stimulation, provided that supraspinal inputs to the lumbar cord were severed by transection just prior to evaluating the reflex. Thus, 7OHDPAT administration in SCI males was able to overcome the detrimental effects of SCI on ejaculatory reflexes

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

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

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