摘要:
Devices and methods for implementing selective, or asymmetric, attenuation of an x-ray beam. In one example, a filter is provided that is substantially in the form of a wedge where some portions of the filter are thicker, and thus provide greater attenuation, than other, thinner portions of the filter. The filter is situated between the target surface of the anode and the x-ray subject so that x-rays generated by the target pass through the filter before reaching the x-ray subject. Specifically, the filter is oriented so that the thicker portion of the filter receives the higher intensity portion of the x-ray beam, while the thinner portion of the filter receives the relatively lower intensity portion of the x-ray beam. Thus, the gain profile of the x-ray beam is flattened so that the intensity, or flux, of the x-ray beam is relatively uniform throughout a substantial portion of the beam profile.
摘要:
Disclosed are systems, methods, and computer program products that generate estimates of errors caused by extraneous radiation in tomographic systems, such as cone-beam computerized tomography (CBCT) systems, fluoroscopic tomography systems, radiographic tomography systems, laminar tomography imaging systems, and the like. In one group of inventions, spatial errors are estimated from projection data collected where a known spatial perturbation has been introduced into radiation intensity of the source. In another group of inventions, temporal errors are estimated from a sequence of projections where a known perturbation in the radiation intensity of the source for different projections has been introduced.
摘要:
Devices and methods for implementing selective, or asymmetric, attenuation of an x-ray beam. In one example, a filter is provided that is substantially in the form of a wedge where some portions of the filter are thicker, and thus provide greater attenuation, than other, thinner portions of the filter. The filter is situated between the target surface of the anode and the x-ray subject so that x-rays generated by the target pass through the filter before reaching the x-ray subject. Specifically, the filter is oriented so that the thicker portion of the filter receives the higher intensity portion of the x-ray beam, while the thinner portion of the filter receives the relatively lower intensity portion of the x-ray beam. Thus, the gain profile of the x-ray beam is flattened so that the intensity, or flux, of the x-ray beam is relatively uniform throughout a substantial portion of the beam profile.
摘要:
An electrodeless fluorescent lamp comprises a closed-loop (“tokamak”) envelope, two ferrite cores, and an induction coil that is disposed on the envelope walls inside the closed-loop formed by the envelope. The envelope comprises two straight tubes of the same diameter. All coils' turns have essential the same length and are parallel to each other and to the closed-loop axis. Each ferrite core encircles a segment of each the coil's turn and one connecting tube. The lamp can be operated at driving frequencies of 100-600 kHz and lamp powers of 50-250 W. The ferrite core power losses were 6-8 W when the lamp was operated at a frequency of 200-300 kHz and lamp power of 140-150 W. The lamp light output was 12,500 lumen and luminous efficacy was 87 LPW.
摘要:
A process and apparatus are provided whereby sulfur and nitrogen oxides as well as carbon monoxides and unburned hydrocarbons are removed from internal combustion engine exhaust gases. The gases are passed through a chamber containing a sulfide and an oxide of iron, copper or zinc. The system is partially self-regenerating and can be used in conjunction with present catalytic converter units or in lieu thereof. In certain embodiments the present invention can also replace muffler units in exhaust systems.
摘要:
An arc radiotherapy and imaging system is provided which includes a first radiation source and a second radiation source. The first radiation source is suitable for treating a region of a patient, and the second radiation source is suitable for imaging the region of the patient. A control is also provided for automatically adjusting system operation, according to a defined schedule, between treating the region of the patient using the first radiation source and imaging the region of the patient using the second radiation source, thereby facilitating both treating and imaging of the region of the patient.
摘要:
Disclosed are systems, methods, and computer program products that generate estimates of errors caused by extraneous radiation in tomographic systems, such as cone-beam computerized tomography (CBCT) systems, fluoroscopic tomography systems, radiographic tomography systems, laminar tomography imaging systems, and the like. In one group of inventions, spatial errors are estimated from projection data collected where a known spatial perturbation has been introduced into radiation intensity of the source. In another group of inventions, temporal errors are estimated from a sequence of projections where a known perturbation in the radiation intensity of the source for different projections has been introduced.
摘要:
A process for removing SO.sub.2 and NO.sub.x from waste gas and recovering sulfur comprising scrubbing the waste gases with a water slurry of FeS in the presence of FeSO.sub.4 and Na.sub.2 SO.sub.4. SO.sub.2 is captured by the formation of FeS.sub.2 and FeSO.sub.4 in the scrubber. By thermal regeneration in a reducing atmosphere the FeS.sub.2 is converted to FeS and Na.sub.2 SO.sub.4 to Na.sub.2 S. The FeS is recycled to the scrubber. The Na.sub.2 S is returned to the system reacting with FeSO.sub.4 to form Na.sub.2 SO.sub.4 and FeS. The last reaction reduces the amount of FeSO.sub.4 entering the regenerator where by an undesirable side reaction, it may be partially converted to SO.sub.2 and Fe.sub.3 O.sub.4.
摘要翻译:一种从废气中除去SO2和NOx并回收硫的方法,包括在FeSO 4和Na 2 SO 4存在下用FeS的水浆料洗涤废气。 通过在洗涤器中形成FeS 2和FeSO 4来捕获SO2。 通过还原气氛中的热再生,FeS2转化为FeS和Na2SO4至Na2S。 FeS被再循环到洗涤器中。 将Na 2 S返回到与FeSO 4反应的体系中以形成Na 2 SO 4和FeS。 最后的反应减少进入再生器的FeSO 4的量,其中由于不期望的副反应,其可以部分地转化为SO 2和Fe 3 O 4。
摘要:
A process and apparatus are provided whereby sulfur and nitrogen oxides as well as carbon monoxides and unburned hydrocarbons are removed from internal combustion engine exhaust gases. The gases are passed through a chamber containing a sulfide and an oxide of iron, copper or zinc. The system is partially self-regenerating and can be used in conjunction with present catalytic converter units or in lieu thereof. In certain embodiments the present invention can also replace muffler units in exhaust systems.