摘要:
Contaminants are cleaned from the surface of a body in space by generating a substantially space-charge neutral reactive plasma, directing the plasma onto the contaminated surface at an energy below the surface sputtering energy (typically 20 eV), and reacting the plasma with the contaminants to remove them. A helicon wave plasma source is made light weight and compact enough for spacecraft use, with a plasma energy low enough to avoid damaging optical surfaces, by using permanent magnets to establish a static axial magnetic field, and a simple but novel rf antenna design. The antenna consists of a pair of spaced conductive rings which extend around the plasma tube, with conductive base and rf feed bars extending between the rings on diametrically opposite sides. The feed bar is interrupted to provide an rf input on opposite sides of the interruption. The antenna is preferably formed as an integral metal unit, with its rings rigidly supported by and integral with opposite ends of the base bar. The plasma source is also useful in neutralizing localized charges on the spacecraft.
摘要:
Contaminants are cleaned from the surface of a body in space by generating a substantially space-charge neutral reactive plasma, directing the plasma onto the contaminated surface at an energy below the surface sputtering energy (typically 20 eV), and reacting the plasma with the contaminants to remove them. A helicon wave plasma source is made light weight and compact enough for spacecraft use, with a plasma energy low enough to avoid damaging optical surfaces, by using permanent magnets to establish a static axial magnetic field, and a simple but novel rf antenna design. The antenna consists of a pair of spaced conductive rings which extend around the plasma tube, with conductive base and rf feed bars extending between the rings on diametrically opposite sides. The feed bar is interrupted to provide an rf input on opposite sides of the interruption. The antenna is preferably formed as an integral metal unit, with its rings rigidly supported by and integral with opposite ends of the base bar. The plasma source is also useful in neutralizing localized charges on the spacecraft.
摘要:
Contaminants are cleaned from the surface of a body in space by generating a substantially space-charge neutral reactive plasma, directing the plasma onto the contaminated surface at an energy below the surface sputtering energy (typically 20 eV), and reacting the plasma with the contaminants to remove them. A helicon wave plasma source is made light weight and compact enough for spacecraft use, with a plasma energy low enough to avoid damaging optical surfaces, by using permanent magnets to establish a static axial magnetic field, and a simple but novel rf antenna design. The antenna consists of a pair of spaced conductive rings which extend around the plasma tube, with conductive base and rf feed bars extending between the rings on diametrically opposite sides. The feed bar is interrupted to provide an rf input on opposite sides of the interruption. The antenna is preferably formed as an integral metal unit, with its rings rigidly supported by and integral with opposite ends of the base bar. The plasma source is also useful in neutralizing localized charges on the spacecraft.
摘要:
Contaminants are cleaned from the surface of a body in space by generating a substantially space-charge neutral reactive plasma, directing the plasma onto the contaminated surface at an energy below the surface sputtering energy (typically 20 eV), and reacting the plasma with the contaminants to remove them. A helicon wave plasma source is made light weight and compact enough for spacecraft use, with a plasma energy low enough to avoid damaging optical surfaces, by using permanent magnets to establish a static axial magnetic field, and a simple but novel rf antenna design. The antenna consists of a pair of spaced conductive rings which extend around the plasma tube, with conductive base and rf feed bars extending between the rings on diametrically opposite sides. The feed bar is interrupted to provide an rf input on opposite sides of the interruption. The antenna is preferably formed as an integral metal unit, with its rings rigidly supported by and integral with opposite ends of the base bar. The plasma source is also useful in neutralizing localized charges on the spacecraft.
摘要:
Contaminant levels in a fluid such as air or water are reduced by producing a pulsed electron beam having an average primary electron energy of from about 90 to about 110 thousand electron volts (corresponding to an average injected electron energy of from about 45 to about 55 thousand electron volts in a preferred case) and directing the electron beam through the fluid. The contaminant compounds may include organic compounds and certain inorganic compounds such as NO.sub.x and SO.sub.x. The fluid is preferably contained in a contaminant reduction cell that is separated from an electron beam source by an electron-transparent window.
摘要:
A high-Q factor resonator comprises a solenoid having an embedded capacitor assembled in a machineable high-frequency dielectric printed circuit board (“PCB”), or other substrate. The solenoid comprises a plurality of surface conductors positioned on upper and lower surfaces of the PCB. The solenoid further comprises a plurality of conductive vias extending through the PCB between the surface conductors, and at least two aligned vias are separated by a capacitive gap. The device can therefore be described as a coupled circuit having a 1.5 or more turn inductor with an embedded capacitor along the length of the conductive path. Accordingly, a resonator having a high-Q factor is provided which is relatively inexpensive and easy to fabricate.
摘要:
Organic compounds showing the ability to inhibit effector toxin secretion or translocation mediated by bacterial type III secretion systems are disclosed. The disclosed type III secretion system inhibitor compounds are useful for combating infections by Gram-negative bacteria such as Salmonella spp., Shigella flexneri, Psendomonas spp., Yersinia spp., en tero pathogenic and enteroinvasive Escherichia coli, and Chlamydia spp. having such type III secretion systems.
摘要:
The present invention is related to the development of compounds and methods for inhibiting viral infection in a mammal. A pseudotype virus was developed for use in a high throughput assay for identifying nonpeptidic small molecule inhibitors that prevent viral entry into a host cell.
摘要:
Ion erosion of grids is reduced in an ion thruster with a multiple-grid ion-optics system. The thruster has an array of aperture sets in which aperture areas change in a perimeter region of the array. In one ion-optics system embodiment, a screen aperture area is reduced and a decelerator aperture area is increased in aperture sets that are proximate to the perimeter of the array. Prototype tests of this embodiment have illustrated significant reduction of ion erosion.
摘要:
A workpiece is heated by first forming an ionized gas plasma around the workpiece. A positive potential is applied to the workpiece to accelerate electrons from the plasma into the workpiece. The workpiece is uniformly surface heated by the energy directed into the workpiece by the electrons. The workpiece is cooled by providing a flow of a pressurized liquid material such as carbon dioxide having a triple point. The liquid material is expanded through a nozzle to form solid particles that contact the surface of the workpiece and remove heat from it by subliming.