基于WIN 0.25μm Ga As赝配高电子迁移率晶体管（PHEMT）工艺,针对大相位移相器容易在宽带情形下出现的性能恶化问题,采用ADS2014仿真软件,成功设计并实现了两款大相位（90°和180°）的X波段（8-12 GHz）宽带数字移相器电路,...基于WIN 0.25μm Ga As赝配高电子迁移率晶体管（PHEMT）工艺,针对大相位移相器容易在宽带情形下出现的性能恶化问题,采用ADS2014仿真软件,成功设计并实现了两款大相位（90°和180°）的X波段（8-12 GHz）宽带数字移相器电路,其拓扑形式为高低通结构,并采用奇偶模分析方法,对高低通滤波网络进行分析。最终在片测试结果表明,其获得了优良的宽带性能,且与仿真结果相吻合。该设计90°移相器电路在频带内相位误差为-3.7°-0°,插入损耗优于2.15 d B,回波损耗优于19 d B;180°移相器电路在频带内相位精度为-6.2°-2°,插入损耗优于2.65 d B,回波损耗优于17 d B。该移相器在相对带宽为40%的X波段内取得良好的插入损耗与回波特性,适用于频带较宽的多位级联数字移相器中。展开更多
In oil and mineral exploration, gravity gradient tensor data include higher- frequency signals than gravity data, which can be used to delineate small-scale anomalies. However, full-tensor gradiometry （FTG） data are...In oil and mineral exploration, gravity gradient tensor data include higher- frequency signals than gravity data, which can be used to delineate small-scale anomalies. However, full-tensor gradiometry （FTG） data are contaminated by high-frequency random noise. The separation of noise from high-frequency signals is one of the most challenging tasks in processing of gravity gradient tensor data. We first derive the Cartesian equations of gravity gradient tensors under the constraint of the Laplace equation and the expression for the gravitational potential, and then we use the Cartesian equations to fit the measured gradient tensor data by using optimal linear inversion and remove the noise from the measured data. Based on model tests, we confirm that not only this method removes the high- frequency random noise but also enhances the weak anomaly signals masked by the noise. Compared with traditional low-pass filtering methods, this method avoids removing noise by sacrificing resolution. Finally, we apply our method to real gravity gradient tensor data acquired by Bell Geospace for the Vinton Dome at the Texas-Louisiana border.展开更多
O438 99031635红外光谱信号的预处理=Preprocessing for infraredspectral signals[刊,中]/方勇华,荀毓龙(中科院安徽光机所.安徽,合肥(230031))//红外与激光工程.—1998,27(2).-17-20介绍了一种对光谱信号进行预处理的高低通综合滤波法。
This paper proposes a spatially denoising algorithm using filtering-based noise estimation for an image corrupted by Gaussian noise.The proposed algorithm consists of two stages:estimation and elimination of noise den...This paper proposes a spatially denoising algorithm using filtering-based noise estimation for an image corrupted by Gaussian noise.The proposed algorithm consists of two stages:estimation and elimination of noise density.To adaptively deal with variety of the noise amount,a noisy input image is firstly filtered by a lowpass filter.Standard deviation of the noise is computed from different images between the noisy input and its filtered image.In addition,a modified Gaussian noise removal filter based on the local statistics such as local weighted mean,local weighted activity and local maximum is used to control the degree of noise suppression.Experiments show the effectiveness of the proposed algorithm.展开更多
This paper presents a compact Ultra-Wideband （UWB） band-pass filter using a high-pass filter and a low-pass one, and the resonator with lumped elements. The structure of our proposed bandpass filter is very simple a...This paper presents a compact Ultra-Wideband （UWB） band-pass filter using a high-pass filter and a low-pass one, and the resonator with lumped elements. The structure of our proposed bandpass filter is very simple and the Defected Ground Structure（DGS） structure is used to get the low-pass filter characteristics. This proposed band-pass filter can be much smaller than a cascaded type filter. As a result of simulation, the insertion loss is less than 0.3 dB throughout the pass-band of 2.2 GHz- 10.6 GHz, while the return loss is more than 18 dB. And it has rejection level of 36 dB at GPS band.展开更多
OBJECTIVE: To investigate the relationship between sleep apnea hypopnea syndrome (SAHS) and some cardiovascular abnormalities in elderly snorers, as well as the effectiveness of nasal continuous positive airway pressu...OBJECTIVE: To investigate the relationship between sleep apnea hypopnea syndrome (SAHS) and some cardiovascular abnormalities in elderly snorers, as well as the effectiveness of nasal continuous positive airway pressure on those with SAHS. METHODS: With the use of polysomnography, 73 elderly snorers (older than 60 years) were examined and placed into either the SAHS group or the control group. Using ambulatory electrocardiogram (ECG) and blood pressure measurement, daily nocturnal rhythm of blood pressure, hypertension, heart rate variability, some arrhythmia and angina pectoris of coronary heart disease (CHD) were monitored and compared between the two groups before and after 5 - 7 days of treatment with nasal continuous positive airway pressure on the SAHS group. RESULTS: This study indicated a higher incidence (47.9%) of sleep apnea syndrome in elderly snorers and demonstrated that there was a significantly higher incidence of hypertension, disappearance in daily nocturnal rhythm of blood pressure, poor effectiveness of nitrate on angina pectoris of coronary heart disease, decreased heart rate variability during sleep, increased arrhythmia and lower pulse oxygen saturation (SpO(2)) levels in the SAHS group than in the control group. After nasal continuous positive airway pressure treatment during sleep, snoring control, significantly higher SpO(2) levels and lower index of apnea/hypopnea were achieved in the SAHS group; heart rate variability (HRV) and blood pressure day nocturnal rhythm were returned to normal levels. CONCLUSION: This research suggests that there is a close relationship between the development of sleep apnea syndrome and some cardiovascular diseases. Continuous positive nasal airway pressure is effective not only on SAHS but also on coexisting cardiovascular disorders.展开更多
文摘基于WIN 0.25μm Ga As赝配高电子迁移率晶体管（PHEMT）工艺,针对大相位移相器容易在宽带情形下出现的性能恶化问题,采用ADS2014仿真软件,成功设计并实现了两款大相位（90°和180°）的X波段（8-12 GHz）宽带数字移相器电路,其拓扑形式为高低通结构,并采用奇偶模分析方法,对高低通滤波网络进行分析。最终在片测试结果表明,其获得了优良的宽带性能,且与仿真结果相吻合。该设计90°移相器电路在频带内相位误差为-3.7°-0°,插入损耗优于2.15 d B,回波损耗优于19 d B;180°移相器电路在频带内相位精度为-6.2°-2°,插入损耗优于2.65 d B,回波损耗优于17 d B。该移相器在相对带宽为40%的X波段内取得良好的插入损耗与回波特性,适用于频带较宽的多位级联数字移相器中。
基金financially supported by the SinoProbe-09-01(201011078)
文摘In oil and mineral exploration, gravity gradient tensor data include higher- frequency signals than gravity data, which can be used to delineate small-scale anomalies. However, full-tensor gradiometry （FTG） data are contaminated by high-frequency random noise. The separation of noise from high-frequency signals is one of the most challenging tasks in processing of gravity gradient tensor data. We first derive the Cartesian equations of gravity gradient tensors under the constraint of the Laplace equation and the expression for the gravitational potential, and then we use the Cartesian equations to fit the measured gradient tensor data by using optimal linear inversion and remove the noise from the measured data. Based on model tests, we confirm that not only this method removes the high- frequency random noise but also enhances the weak anomaly signals masked by the noise. Compared with traditional low-pass filtering methods, this method avoids removing noise by sacrificing resolution. Finally, we apply our method to real gravity gradient tensor data acquired by Bell Geospace for the Vinton Dome at the Texas-Louisiana border.
文摘O438 99031635红外光谱信号的预处理=Preprocessing for infraredspectral signals[刊,中]/方勇华,荀毓龙(中科院安徽光机所.安徽,合肥(230031))//红外与激光工程.—1998,27(2).-17-20介绍了一种对光谱信号进行预处理的高低通综合滤波法。
基金supported by the Korea Science and Engineering Foundation(KOSEF) grant fund by the Korea Govern-ment(MEST)(No.2011-0000148)the Ministry of Knowledge Economy,Korea under the Infor mation Technology Research Center support programsupervised by the National IT Industry Promotion Agency(NIPA-2011-C1090-1121-0010)
文摘This paper proposes a spatially denoising algorithm using filtering-based noise estimation for an image corrupted by Gaussian noise.The proposed algorithm consists of two stages:estimation and elimination of noise density.To adaptively deal with variety of the noise amount,a noisy input image is firstly filtered by a lowpass filter.Standard deviation of the noise is computed from different images between the noisy input and its filtered image.In addition,a modified Gaussian noise removal filter based on the local statistics such as local weighted mean,local weighted activity and local maximum is used to control the degree of noise suppression.Experiments show the effectiveness of the proposed algorithm.
基金supported by the IT R&D program of MKE/ⅡTA:Study of technologies for improvingthe RF spectrum characteristics by using the meta-electromagnetic structure[2009-F-033-01]
文摘This paper presents a compact Ultra-Wideband （UWB） band-pass filter using a high-pass filter and a low-pass one, and the resonator with lumped elements. The structure of our proposed bandpass filter is very simple and the Defected Ground Structure（DGS） structure is used to get the low-pass filter characteristics. This proposed band-pass filter can be much smaller than a cascaded type filter. As a result of simulation, the insertion loss is less than 0.3 dB throughout the pass-band of 2.2 GHz- 10.6 GHz, while the return loss is more than 18 dB. And it has rejection level of 36 dB at GPS band.
文摘OBJECTIVE: To investigate the relationship between sleep apnea hypopnea syndrome (SAHS) and some cardiovascular abnormalities in elderly snorers, as well as the effectiveness of nasal continuous positive airway pressure on those with SAHS. METHODS: With the use of polysomnography, 73 elderly snorers (older than 60 years) were examined and placed into either the SAHS group or the control group. Using ambulatory electrocardiogram (ECG) and blood pressure measurement, daily nocturnal rhythm of blood pressure, hypertension, heart rate variability, some arrhythmia and angina pectoris of coronary heart disease (CHD) were monitored and compared between the two groups before and after 5 - 7 days of treatment with nasal continuous positive airway pressure on the SAHS group. RESULTS: This study indicated a higher incidence (47.9%) of sleep apnea syndrome in elderly snorers and demonstrated that there was a significantly higher incidence of hypertension, disappearance in daily nocturnal rhythm of blood pressure, poor effectiveness of nitrate on angina pectoris of coronary heart disease, decreased heart rate variability during sleep, increased arrhythmia and lower pulse oxygen saturation (SpO(2)) levels in the SAHS group than in the control group. After nasal continuous positive airway pressure treatment during sleep, snoring control, significantly higher SpO(2) levels and lower index of apnea/hypopnea were achieved in the SAHS group; heart rate variability (HRV) and blood pressure day nocturnal rhythm were returned to normal levels. CONCLUSION: This research suggests that there is a close relationship between the development of sleep apnea syndrome and some cardiovascular diseases. Continuous positive nasal airway pressure is effective not only on SAHS but also on coexisting cardiovascular disorders.
