Beam lifetime is dominated by Touschek scattering at the Shanghai Synchrotron Radiation Facility(SSRF).Touschek loss rate is affected by probability for scattering beyond the RF acceptance and the volume charge densit...Beam lifetime is dominated by Touschek scattering at the Shanghai Synchrotron Radiation Facility(SSRF).Touschek loss rate is affected by probability for scattering beyond the RF acceptance and the volume charge density of the bench.In the phaseⅡupgrade of the SSRF,a third harmonic superconducting cavity will be used to enhance the Touschek lifetime by lengthening the bunches.The Touschek lifetime improvement factor is affected by the voltage of a harmonic cavity.To stabilize the cavity voltage,a tuning control system was designed to control it.The design of the tuning control system was based on the SSRF third-generation low-level RF control system.Some hardware and specialized algorithms were redesigned to fit the harmonic cavity control.The design of the tuning control system is complete,and the control system has been tested.The test result shows that the fluctuation of amplitude is<±0.34%within 1.5 h,which satisfies the stability requirement.展开更多
The aim of this paper is to achieve the radio frequency stealth(RFS) during the course of tracking by controlling the radiation energy and the interval of a radar. Firstly, we build the model of probability of interce...The aim of this paper is to achieve the radio frequency stealth(RFS) during the course of tracking by controlling the radiation energy and the interval of a radar. Firstly, we build the model of probability of interception with the once radiation during the course of tracking. Secondly, we establish the model of the cumulative probability of interception to describe the effect of RFS throughout the tracking process and obtain two solutions that are minimizing the probability of interception and the radiation times to reduce the cumulative probability of interception. Thirdly, we propose a self-adapting radiation energy control method(SARE)to minimize the probability of interception. Fourthly, we propose a self-adapting radiation interval control method(SARI) to minimize radiation times. Fifthly, combining SARE with SARI, we propose a SARE-SARI control method(SAEI) during the course of tracking.Finally, we compare SAEI with two others by simulation, and the results show the effect of RFS of SAEI is better than the other two,but we have to make a trade-off between the ability of RFS and the effect of tracking.展开更多
This paper presents a method of generating terahertz （THz） coherent transition radiation （CTR） from picosecond ultrashort electron bunches including single and train bunches, which are produced by a photocathode r...This paper presents a method of generating terahertz （THz） coherent transition radiation （CTR） from picosecond ultrashort electron bunches including single and train bunches, which are produced by a photocathode radio frequency gun. The radiation characteristics of THz CTR including formation factor and energy spectrum are analysed in detail. With the help of a 2-dimensional particle-in-cell simulation, the radiation characteristics including power, energy and magnetic field are analysed. The results show that the radiation frequency can be adjusted by tuning the repetition frequency of the train bunch and the energy can be enhanced with the train bunches.展开更多
Radio frequency interference(RFI)will pollute the weak astronomical signals received by radio telescopes,which in return will seriously affect the time-domain astronomical observation and research.In this paper,we use...Radio frequency interference(RFI)will pollute the weak astronomical signals received by radio telescopes,which in return will seriously affect the time-domain astronomical observation and research.In this paper,we use a deep learning method to identify RFI in frequency spectrum data,and propose a neural network based on Unet that combines the principles of depthwise separable convolution and residual,named DSC Based Dual-Resunet.Compared with the existing Unet network,DSC Based Dual-Resunet performs better in terms of accuracy,F1 score,and MIoU,and is also better in terms of computation cost where the model size and parameter amount are 12.5%of Unet and the amount of computation is 38%of Unet.The experimental results show that the proposed network is a high-performance and lightweight network,and it is hopeful to be applied to RFI identification of radio telescopes on a large scale.展开更多
Carcinogenesis fits in a frequency pattern of electromagnetic field (EMF) waves, in which a gradual loss of cellular organization occurs. Such generation of cancer features can be inhibited by adequate exposure to coh...Carcinogenesis fits in a frequency pattern of electromagnetic field (EMF) waves, in which a gradual loss of cellular organization occurs. Such generation of cancer features can be inhibited by adequate exposure to coherent electromagnetic frequencies. However, cancer can also be initiated and promoted at other distinct frequencies of electromagnetic waves. Both observations were revealed by analyzing 100 different EMF frequency data reported in a meta-analyses of 123 different, earlier published, biomedical studies. The studied EM frequencies showed a fractal pattern of 12 beneficial (anti-cancer) frequencies, and 12 detrimental (cancer promoting) frequencies, that form the central pattern of a much wider self-similar EMF spectrum of cancer inhibiting or promoting activities. Inhibiting of the cancer process, and even curing of the disease, can thus be considered through exposure to the coherent type of EM fields. Stabilization of the disease can be understood by constructive resonance of macromolecules in the cancer cell with the externally appied coherent EMF field frequencies, called solitons/polarons. The latter, for instance, have been shown earlier to induce repair in DNA/RNA conformation and/or epigenetic changes. The field of EMF treatment of cancer disorders is rapidly expanding and our studies may invite further experimental and clinical studies in which systematically various potential EMF treatment protocols could be applied, with combined and modulated frequencies, to obtain even more efficient EMF anti-cancer therapies.展开更多
A ten-month field research study was meticulously conducted at Robert Moses State Park (RMSP) on the south shore of Long Island, NY. The objective was to determine if aerial phenomena of an unknown nature exist over a...A ten-month field research study was meticulously conducted at Robert Moses State Park (RMSP) on the south shore of Long Island, NY. The objective was to determine if aerial phenomena of an unknown nature exist over a coastal location and to characterize their properties and behaviors. Primary and secondary field observation methods were utilized in this data-centric study. Forensic engineering principles and methodologies guided the study. The challenges set forward were object detection, observation, and characterization, where multispectral electro-optical devices and radar were employed due to limited visual acuity and intermittent presentation of the phenomena. The primary means of detection utilized a 3 cm X-band radar operating in two scan geometries, the X- and Y-axis. Multispectral electro-optical devices were utilized as a secondary means of detection and identification. Data was emphasized using HF and LF detectors and spectrum analyzers incorporating EM, ultrasonic, magnetic, and RF field transducers to record spectral data in these domains. Data collection concentrated on characterizing VIS, NIR, SWIR, LWIR, UVA, UVB, UVC, and the higher energy spectral range of ionizing radiation (alpha, beta, gamma, and X-ray) recorded by Geiger-Müller counters as well as special purpose semiconductor diode sensors.展开更多
采用sXc(System for s Xposure of cells)辐照系统、GSM talk信号、频率1950 MHz、SAR值为3 W/kg的射频辐射,辐照小鼠睾丸间质细胞系TM3细胞,连续照射24 h,同时设假辐照组。辐照后,将部分辐照组和假辐照组细胞接种于9块96孔板内,采用CCK...采用sXc(System for s Xposure of cells)辐照系统、GSM talk信号、频率1950 MHz、SAR值为3 W/kg的射频辐射,辐照小鼠睾丸间质细胞系TM3细胞,连续照射24 h,同时设假辐照组。辐照后,将部分辐照组和假辐照组细胞接种于9块96孔板内,采用CCK8试剂盒测定照射后1-9 d细胞增殖能力,绘制生长曲线。另一部分辐照组与假辐照组细胞接种于不同的10 cm培养皿中,分别于照射后1、2、3、4和5 d用流式细胞仪检测细胞周期和细胞凋亡的变化。结果显示,照射后2-9 d辐照组细胞增殖能力低于假辐照组细胞(p<0.05);照射后1-5 d,辐照组细胞周期S期比假辐照组延长(p<0.05),且于照射后3-5 d辐照组细胞周期G1期比假辐照组缩短(p<0.05);而照射后1-5 d辐照组细胞凋亡与假辐照组无差异。频率1950 MHz的GSM talk信号射频辐射照射小鼠睾丸间质细胞24 h后,可以通过改变细胞周期,进而抑制细胞增殖,影响TM3细胞生物学作用的发挥,具体的作用机制尚有待于进一步研究。展开更多
目的:探讨迭代重建技术在CT引导下射频消融治疗肝脏肿瘤中的应用价值。方法:选取50例进行CT引导下肝脏射频消融治疗肝脏肿瘤的患者,首次扫描采用常规剂量(130 k V、参考毫安秒250 m As)扫描滤波反投影(filtered back projection,FBP)重...目的:探讨迭代重建技术在CT引导下射频消融治疗肝脏肿瘤中的应用价值。方法:选取50例进行CT引导下肝脏射频消融治疗肝脏肿瘤的患者,首次扫描采用常规剂量(130 k V、参考毫安秒250 m As)扫描滤波反投影(filtered back projection,FBP)重建,后续监测电极针插入肿瘤过程扫描均采用低剂量(130 k V、参考毫安秒90 m As)扫描图像域迭代重建(iterative reconstruction in image space,IRIS),记录每次扫描的容积CT剂量指数(CT dose index volumes,CTDIvol)、剂量长度乘积(dose length product,DLP),并计算有效剂量(effect dose,ED)。结果:常规剂量组CTDIvol为(15.13±3.88)m Gy,DLP为(277.97±47.41)m Gy·cm,ED为(4.17±0.71)m Sv;低剂量组CTDIvol为(5.45±2.35)m Gy,DLP为(100.07±18.35)m Gy·cm,ED为(1.55±0.36)m Sv,低剂量组比常规剂量组辐射剂量降低了64%。2组的图像质量均能满足射频消融治疗监测电极针的诊断要求。结论:将迭代重建技术应用到CT引导下射频消融治疗肝脏肿瘤中,可以大幅降低辐射剂量,值得临床推广。展开更多
文摘Beam lifetime is dominated by Touschek scattering at the Shanghai Synchrotron Radiation Facility(SSRF).Touschek loss rate is affected by probability for scattering beyond the RF acceptance and the volume charge density of the bench.In the phaseⅡupgrade of the SSRF,a third harmonic superconducting cavity will be used to enhance the Touschek lifetime by lengthening the bunches.The Touschek lifetime improvement factor is affected by the voltage of a harmonic cavity.To stabilize the cavity voltage,a tuning control system was designed to control it.The design of the tuning control system was based on the SSRF third-generation low-level RF control system.Some hardware and specialized algorithms were redesigned to fit the harmonic cavity control.The design of the tuning control system is complete,and the control system has been tested.The test result shows that the fluctuation of amplitude is<±0.34%within 1.5 h,which satisfies the stability requirement.
基金supported by the National Natural Science Foundation of China(61472441)
文摘The aim of this paper is to achieve the radio frequency stealth(RFS) during the course of tracking by controlling the radiation energy and the interval of a radar. Firstly, we build the model of probability of interception with the once radiation during the course of tracking. Secondly, we establish the model of the cumulative probability of interception to describe the effect of RFS throughout the tracking process and obtain two solutions that are minimizing the probability of interception and the radiation times to reduce the cumulative probability of interception. Thirdly, we propose a self-adapting radiation energy control method(SARE)to minimize the probability of interception. Fourthly, we propose a self-adapting radiation interval control method(SARI) to minimize radiation times. Fifthly, combining SARE with SARI, we propose a SARE-SARI control method(SAEI) during the course of tracking.Finally, we compare SAEI with two others by simulation, and the results show the effect of RFS of SAEI is better than the other two,but we have to make a trade-off between the ability of RFS and the effect of tracking.
基金Project supported by the Key Program of National Natural Science Foundation of China (Grant No.10705050)National Natural Science Foundation of China (Grant Nos.10875070,10805031,and 10905032)+1 种基金China Postdoctoral Science Foundation (Grant No.20080440031)China Postdoctoral Special Science Foundation (Grant No.200902088)
文摘This paper presents a method of generating terahertz （THz） coherent transition radiation （CTR） from picosecond ultrashort electron bunches including single and train bunches, which are produced by a photocathode radio frequency gun. The radiation characteristics of THz CTR including formation factor and energy spectrum are analysed in detail. With the help of a 2-dimensional particle-in-cell simulation, the radiation characteristics including power, energy and magnetic field are analysed. The results show that the radiation frequency can be adjusted by tuning the repetition frequency of the train bunch and the energy can be enhanced with the train bunches.
基金supported by the National Natural Science Foundation of China(Grant No.11790305)partially supported by the Specialized Research Fund for State Key Laboratories(Grant No.SYS-202002-04)。
文摘Radio frequency interference(RFI)will pollute the weak astronomical signals received by radio telescopes,which in return will seriously affect the time-domain astronomical observation and research.In this paper,we use a deep learning method to identify RFI in frequency spectrum data,and propose a neural network based on Unet that combines the principles of depthwise separable convolution and residual,named DSC Based Dual-Resunet.Compared with the existing Unet network,DSC Based Dual-Resunet performs better in terms of accuracy,F1 score,and MIoU,and is also better in terms of computation cost where the model size and parameter amount are 12.5%of Unet and the amount of computation is 38%of Unet.The experimental results show that the proposed network is a high-performance and lightweight network,and it is hopeful to be applied to RFI identification of radio telescopes on a large scale.
文摘Carcinogenesis fits in a frequency pattern of electromagnetic field (EMF) waves, in which a gradual loss of cellular organization occurs. Such generation of cancer features can be inhibited by adequate exposure to coherent electromagnetic frequencies. However, cancer can also be initiated and promoted at other distinct frequencies of electromagnetic waves. Both observations were revealed by analyzing 100 different EMF frequency data reported in a meta-analyses of 123 different, earlier published, biomedical studies. The studied EM frequencies showed a fractal pattern of 12 beneficial (anti-cancer) frequencies, and 12 detrimental (cancer promoting) frequencies, that form the central pattern of a much wider self-similar EMF spectrum of cancer inhibiting or promoting activities. Inhibiting of the cancer process, and even curing of the disease, can thus be considered through exposure to the coherent type of EM fields. Stabilization of the disease can be understood by constructive resonance of macromolecules in the cancer cell with the externally appied coherent EMF field frequencies, called solitons/polarons. The latter, for instance, have been shown earlier to induce repair in DNA/RNA conformation and/or epigenetic changes. The field of EMF treatment of cancer disorders is rapidly expanding and our studies may invite further experimental and clinical studies in which systematically various potential EMF treatment protocols could be applied, with combined and modulated frequencies, to obtain even more efficient EMF anti-cancer therapies.
文摘A ten-month field research study was meticulously conducted at Robert Moses State Park (RMSP) on the south shore of Long Island, NY. The objective was to determine if aerial phenomena of an unknown nature exist over a coastal location and to characterize their properties and behaviors. Primary and secondary field observation methods were utilized in this data-centric study. Forensic engineering principles and methodologies guided the study. The challenges set forward were object detection, observation, and characterization, where multispectral electro-optical devices and radar were employed due to limited visual acuity and intermittent presentation of the phenomena. The primary means of detection utilized a 3 cm X-band radar operating in two scan geometries, the X- and Y-axis. Multispectral electro-optical devices were utilized as a secondary means of detection and identification. Data was emphasized using HF and LF detectors and spectrum analyzers incorporating EM, ultrasonic, magnetic, and RF field transducers to record spectral data in these domains. Data collection concentrated on characterizing VIS, NIR, SWIR, LWIR, UVA, UVB, UVC, and the higher energy spectral range of ionizing radiation (alpha, beta, gamma, and X-ray) recorded by Geiger-Müller counters as well as special purpose semiconductor diode sensors.
文摘目的:探讨迭代重建技术在CT引导下射频消融治疗肝脏肿瘤中的应用价值。方法:选取50例进行CT引导下肝脏射频消融治疗肝脏肿瘤的患者,首次扫描采用常规剂量(130 k V、参考毫安秒250 m As)扫描滤波反投影(filtered back projection,FBP)重建,后续监测电极针插入肿瘤过程扫描均采用低剂量(130 k V、参考毫安秒90 m As)扫描图像域迭代重建(iterative reconstruction in image space,IRIS),记录每次扫描的容积CT剂量指数(CT dose index volumes,CTDIvol)、剂量长度乘积(dose length product,DLP),并计算有效剂量(effect dose,ED)。结果:常规剂量组CTDIvol为(15.13±3.88)m Gy,DLP为(277.97±47.41)m Gy·cm,ED为(4.17±0.71)m Sv;低剂量组CTDIvol为(5.45±2.35)m Gy,DLP为(100.07±18.35)m Gy·cm,ED为(1.55±0.36)m Sv,低剂量组比常规剂量组辐射剂量降低了64%。2组的图像质量均能满足射频消融治疗监测电极针的诊断要求。结论:将迭代重建技术应用到CT引导下射频消融治疗肝脏肿瘤中,可以大幅降低辐射剂量,值得临床推广。
