A novel transit-time oscillator(TTO)is proposed in this paper.An axial cathode which has been widely used in high power microwave(HPM)source and an extractor with radial feature are adopted.In this way,the inherent ad...A novel transit-time oscillator(TTO)is proposed in this paper.An axial cathode which has been widely used in high power microwave(HPM)source and an extractor with radial feature are adopted.In this way,the inherent advantages of axial and radial TTO,both of which can be utilized as high-quality intense relativistic electron beam(IREB),can be generated and the power capacity is also increased.The working mode isπ/2 mode of TM01 based on small-signal theory,and under the same energy storage,the maximum electric field in extractor decreases 16.3%.Besides,by utilizing the natural bending of the solenoid,this TTO saves over 60%of the length required by the uniform magnetic field,and consequently reduces the energy consumed by solenoid.The PIC simulation shows that by using 1.0-T decreasing magnetic field generated by the shorter solenoid,3.37-GW microwave at 12.43 GHz is generated with 620-kV and 13.27-kA input,and the overall conversion efficiency is 41%.展开更多
In Mali, cholesteatoma surgery remains a challenge due to the limited number of otological practitioners, and the low socio-economic level of patients reflecting the difficulties in performing CT or MRI for post-opera...In Mali, cholesteatoma surgery remains a challenge due to the limited number of otological practitioners, and the low socio-economic level of patients reflecting the difficulties in performing CT or MRI for post-operative follow-up. We therefore initiated this work with the objective of analyzing, through a broad bibliographic review, the clinical, paraclinical, topographical, therapeutic and progressive aspects of a series of ear cholesteatoma. Materials and Method: This was a retrospective and prospective, descriptive study that took place in the ENT and head and neck surgery department of the Gabriel Touré University Hospital over 36 months from November 2020 to October 2023. These were patients admitted to the department for chronic cholestematous otitis media. Result: In total, we collected 34 files of patients admitted for cholesteatoma. This represented 9% of cases compared to all otological surgeries carried out during the same period, i.e. 362 cases. The average age of our patients was 35.31 years, with extremes ranging from 7 years to 80 years, there were 24 men and 10 women, i.e. a M/F ratio of 2.4. The average time to diagnosis was 7 years. The main functional signs were dominated by chronic fetid purulent otorrhea associated with hypoacusis in 94.6% of cases. One case of meningeal complication and three cases of cerebral empyema were reported. Clinically, a postero-superior and marginal tympanic perforation was observed in 53%, a retraction pocket in 5.9%, the sentinel polyp in 9%, and a non-marginal tympanic perforation in 32%. Pure-tone audiometry performed preoperatively for all patients showed conductive hearing loss in 83%. In 82% of cases we created a recess with the creation of a mini box. An ossiculoplasty was performed immediately with fragments of cartilage. The postoperative course found the disappearance of otorrhea (88.23%), the persistence of otorrhea in one case, two cases of facial paralysis, and one case of tinnitus. We did not identify any cases of scar stenosis of meatoplasty. Hearing was improved or preserved in 91.17% of cases and 3 cases of worsening hypoacusis.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.61701516)
文摘A novel transit-time oscillator(TTO)is proposed in this paper.An axial cathode which has been widely used in high power microwave(HPM)source and an extractor with radial feature are adopted.In this way,the inherent advantages of axial and radial TTO,both of which can be utilized as high-quality intense relativistic electron beam(IREB),can be generated and the power capacity is also increased.The working mode isπ/2 mode of TM01 based on small-signal theory,and under the same energy storage,the maximum electric field in extractor decreases 16.3%.Besides,by utilizing the natural bending of the solenoid,this TTO saves over 60%of the length required by the uniform magnetic field,and consequently reduces the energy consumed by solenoid.The PIC simulation shows that by using 1.0-T decreasing magnetic field generated by the shorter solenoid,3.37-GW microwave at 12.43 GHz is generated with 620-kV and 13.27-kA input,and the overall conversion efficiency is 41%.
文摘In Mali, cholesteatoma surgery remains a challenge due to the limited number of otological practitioners, and the low socio-economic level of patients reflecting the difficulties in performing CT or MRI for post-operative follow-up. We therefore initiated this work with the objective of analyzing, through a broad bibliographic review, the clinical, paraclinical, topographical, therapeutic and progressive aspects of a series of ear cholesteatoma. Materials and Method: This was a retrospective and prospective, descriptive study that took place in the ENT and head and neck surgery department of the Gabriel Touré University Hospital over 36 months from November 2020 to October 2023. These were patients admitted to the department for chronic cholestematous otitis media. Result: In total, we collected 34 files of patients admitted for cholesteatoma. This represented 9% of cases compared to all otological surgeries carried out during the same period, i.e. 362 cases. The average age of our patients was 35.31 years, with extremes ranging from 7 years to 80 years, there were 24 men and 10 women, i.e. a M/F ratio of 2.4. The average time to diagnosis was 7 years. The main functional signs were dominated by chronic fetid purulent otorrhea associated with hypoacusis in 94.6% of cases. One case of meningeal complication and three cases of cerebral empyema were reported. Clinically, a postero-superior and marginal tympanic perforation was observed in 53%, a retraction pocket in 5.9%, the sentinel polyp in 9%, and a non-marginal tympanic perforation in 32%. Pure-tone audiometry performed preoperatively for all patients showed conductive hearing loss in 83%. In 82% of cases we created a recess with the creation of a mini box. An ossiculoplasty was performed immediately with fragments of cartilage. The postoperative course found the disappearance of otorrhea (88.23%), the persistence of otorrhea in one case, two cases of facial paralysis, and one case of tinnitus. We did not identify any cases of scar stenosis of meatoplasty. Hearing was improved or preserved in 91.17% of cases and 3 cases of worsening hypoacusis.
