Exchanges and mutual learning between the Chinese and foreign civilizations are an important part of human cultural development.The Chinese civilization adopts an all-embracing,open and inclusive attitude to understan...Exchanges and mutual learning between the Chinese and foreign civilizations are an important part of human cultural development.The Chinese civilization adopts an all-embracing,open and inclusive attitude to understand the different views of different civilizations on the connotation of values.The ancient Silk Road has opened a new window of friendship between countries and written a new chapter in the development of mankind.展开更多
At the beginning of 2017,on behalf of the Editorial Board of Green Energy&Environment(GEE),we wish all of our readers,authors and reviewers a very happy and successful2017.Looking back to 2016,GEE has received man...At the beginning of 2017,on behalf of the Editorial Board of Green Energy&Environment(GEE),we wish all of our readers,authors and reviewers a very happy and successful2017.Looking back to 2016,GEE has received many submissions from many countries all over the world since it was launched in April 2016.In the former three issues published,we remain committed to delivering those articles which should be展开更多
Downward Looking Sparse Linear Array Three Dimensional SAR(DLSLA 3D SAR) is an important form of 3D SAR imaging, which has a widespread application field. Since its practical equivalent phase centers are usually distr...Downward Looking Sparse Linear Array Three Dimensional SAR(DLSLA 3D SAR) is an important form of 3D SAR imaging, which has a widespread application field. Since its practical equivalent phase centers are usually distributed sparsely and nonuniformly, traditional 3D SAR algorithms suffer from low resolution and high sidelobes in cross-track dimension. To deal with this problem, this paper introduces a method based on back-projection and convex optimization to achieve 3D high accuracy imaging reconstruction. Compared with traditional SAR algorithms, the proposed method sufficiently utilizes the sparsity of the 3D SAR imaging scene and can achieve lower sidelobes and higher resolution in cross-track dimension. In the simulated experiments, the reconstructed results of both simple and complex imaging scene verify that the proposed method outperforms 3D back-projection algorithm and shows satisfying cross-track dimensional resolution and good robustness to noise.展开更多
China’s engagement in global affairs has changed substantially in the 2010s.One aspect of the country’s global reorientation has been its increased interest in,and willingness to play a role in,global health.In the ...China’s engagement in global affairs has changed substantially in the 2010s.One aspect of the country’s global reorientation has been its increased interest in,and willingness to play a role in,global health.In the early 2010s,the UK Department for International Development(DFID)initiated a collaboration with the Chinese government on a programme to support the country to play a greater and more effective global role in health and explore how the UK and China could work together on issues of key concern and contribute to improved global development outcomes.The programme worked with key Chinese agencies to carry out capacity building,support analysis of China’s approaches to engagement in global health governance and assistance,and provide support to government decision making.It also trialled several small-scale interventions in third countries through which Chinese agencies gained experience of working on health programmes overseas.The article reports on the main findings of an evaluation commissioned by DFID to learn from the programme.The programme provided support at a key time in China’s global reorientation;however,there is a need for continued development of capacity and systems for China to play the role envisaged by the country’s leadership.There is also a need for continued exploration on the part of China and partners of how to effectively collaborate to support improved global outcomes.展开更多
A method of underwater simultaneous localization and mapping (SLAM) based on forward-looking sonar was proposed in this paper. Positions of objects were obtained by the forward-looking sonar, and an improved associa...A method of underwater simultaneous localization and mapping (SLAM) based on forward-looking sonar was proposed in this paper. Positions of objects were obtained by the forward-looking sonar, and an improved association method based on an ant colony algorithm was introduced to estimate the positions. In order to improve the precision of the positions, the extended Kalman filter (EKF) was adopted. The presented algorithm was tested in a tank, and the maximum estimation error of SLAM gained was 0.25 m. The tests verify that this method can maintain better association efficiency and reduce navigatioJ~ error.展开更多
BACKGROUND Left bundle branch pacing(LBBP)is a novel pacing modality of cardiac resynchronization therapy(CRT)that achieves more physiologic native ventricular activation than biventricular pacing(BiVP).AIM To explore...BACKGROUND Left bundle branch pacing(LBBP)is a novel pacing modality of cardiac resynchronization therapy(CRT)that achieves more physiologic native ventricular activation than biventricular pacing(BiVP).AIM To explore the validity of electromechanical resynchronization,clinical and echocardiographic response of LBBP-CRT.METHODS Systematic review and Meta-analysis were conducted in accordance with the standard guidelines as mentioned in detail in the methodology section.RESULTS In our analysis,the success rate of LBBP-CRT was determined to be 91.1%.LBBP CRT significantly shortened QRS duration,with significant improvement in echocardiographic parameters,including left ventricular ejection fraction,left ventricular end-diastolic diameter and left ventricular end-systolic diameter in comparison with BiVP-CRT.CONCLUSION A significant reduction in New York Heart Association class and B-type natriuretic peptide levels was also observed in the LBBP-CRT group vs BiVP-CRT group.Lastly,the LBBP-CRT cohort had a reduced pacing threshold at follow-up as compared to BiVP-CRT.展开更多
1.Through the construction during the last fourty years andespecially under the guidance of the“Reform and opening”policy,the power generation equipment manufacturing industry of Chinahas achieved tremendous develop...1.Through the construction during the last fourty years andespecially under the guidance of the“Reform and opening”policy,the power generation equipment manufacturing industry of Chinahas achieved tremendous development in the 1980’s.Whatever展开更多
The bistatic Synthetic Aperture Radar (SAR) systems with separate transmitter and receiver antennas provide a new potential to imaging in the forward-looking geometry. Analysis of the Doppler property in this paper in...The bistatic Synthetic Aperture Radar (SAR) systems with separate transmitter and receiver antennas provide a new potential to imaging in the forward-looking geometry. Analysis of the Doppler property in this paper indicates the feasibility of Bistatic Forward-Looking (BFL) SAR imaging. Considering the different Doppler property determined by the two platforms in BFL SAR, a new 2-D point target spectrum is derived in our study. Based on the spectrum, an imaging method is chosen for the configuration, and the point target simulation validates the analysis.展开更多
The deleterious effects of long-term right ventricular pacing necessitated the search for alternative pacing sites which could prevent or alleviate pacinginduced cardiomyopathy.Until recently,biventricular pacing(BiVP...The deleterious effects of long-term right ventricular pacing necessitated the search for alternative pacing sites which could prevent or alleviate pacinginduced cardiomyopathy.Until recently,biventricular pacing(BiVP)was the only modality which could mitigate or prevent pacing induced dysfunction.Further,BiVP could resynchronize the baseline electromechanical dssynchrony in heart failure and improve outcomes.However,the high non-response rate of around 20%-30%remains a major limitation.This non-response has been largely attributable to the direct non-physiological stimulation of the left ventricular myocardium bypassing the conduction system.To overcome this limitation,the concept of conduction system pacing(CSP)came up.Despite initial success of the first CSP via His bundle pacing(HBP),certain drawbacks including lead instability and dislodgements,steep learning curve and rapid battery depletion on many occasions prevented its widespread use for cardiac resynchronization therapy(CRT).Subsequently,CSP via left bundle branch-area pacing(LBBP)was developed in 2018,which over the last few years has shown efficacy comparable to BiVP-CRT in small observational studies.Further,its safety has also been well established and is largely free of the pitfalls of the HBP-CRT.In the recent metanalysis by Yasmin et al,comprising of 6 studies with 389 participants,LBBPCRT was superior to BiVP-CRT in terms of QRS duration,left ventricular ejection fraction,cardiac chamber dimensions,lead thresholds,and functional status amongst heart failure patients with left bundle branch block.However,there are important limitations of the study including the small overall numbers,inclusion of only a single small randomized controlled trial(RCT)and a small follow-up duration.Further,the entire study population analyzed was from China which makes generalizability a concern.Despite the concerns,the meta-analysis adds to the growing body of evidence demonstrating the efficacy of LBBP-CRT.At this stage,one must acknowledge that the fact that still our opinions on this technique are largely based on observational data and there is a dire need for larger RCTs to ascertain the position of LBBPCRT in management of heart failure patients with left bundle branch block.展开更多
The clutter direction-Doppler curves are not aligned on the near range bins for forward looking airborne radar. As a result, the performance of clutter suppression by Space-Time Adaptive Processing (STAP) degrades gre...The clutter direction-Doppler curves are not aligned on the near range bins for forward looking airborne radar. As a result, the performance of clutter suppression by Space-Time Adaptive Processing (STAP) degrades greatly because of the clutter range dependence. To deal with this problem, a new compensated method is proposed in this paper. The method rebuilds the clutter covariance matrix based on spatial high resolution Minimum Variance Distortionless Response (MVDR) spectrum, and then finds a matrix to transform the covariance matrix of short-range gate to the referred far-range gate. The method can compensate the clutter range dependence well. The simulation results show validity of the method.展开更多
Aiming at a novel missile-borne detector in the optional burst height proximity fuze, a self-adaptive high-resolution forward-looking imaging algorithm (SAHRFL-IA) is presented. The echo data are captured by the missi...Aiming at a novel missile-borne detector in the optional burst height proximity fuze, a self-adaptive high-resolution forward-looking imaging algorithm (SAHRFL-IA) is presented. The echo data are captured by the missile-borne detector in the target regions;thereby the azimuth angulation accuracy at the same distance dimension is improved dynamically. Thus, azimuth information of the targets in the detection area may be obtained accurately. The proposed imaging algorithm breaks through the conventional misconception of merely using azimuth discrimination curves under ideal conditions during monopulse angulation. The real-time echo data from the target region are used to perform error correction for this discrimination curve, and finally the accuracy of the azimuth angulation may reach the optimum at the same distance dimension. A series of experiments demonstrate the validity, reliability and high performance of the proposed imaging algorithm. Azimuth angulation accuracy may reach ten times that of the detection beam width. Meanwhile, the running time of this algorithm satisfies the requirements of missile-borne platforms.展开更多
When the Airborne Early Warning(AEW) radar transmits medial or high Pulse Repetitive Frequency(PRF) signal,the range ambiguity occurs.The clutter of short-range clutter has serious range dependence problem for non-Sid...When the Airborne Early Warning(AEW) radar transmits medial or high Pulse Repetitive Frequency(PRF) signal,the range ambiguity occurs.The clutter of short-range clutter has serious range dependence problem for non-Side Looking Airborne Radar(non-SLAR).As a result,the clutter plus noise covariance matrix can not be estimated correctly,and the performance of clutter suppression obtained by Space-Time Adaptive Processing(STAP) degrades greatly.The uniform linear array has not elevation degrees;therefore,the short-range clutter can not be suppressed directly.A short-range clutter suppression method is proposed.The method first estimate the elevation angles of the ambiguous short-range gate,then eliminates short-range clutter by space time interpolation and adds moving target protection in the procedure.This method can suppress the short-range clutter well.Simulation results show the validity of the method.展开更多
In the spaceborne/airborne forward-looking bistatic syn- thetic aperture radar (SA-FBSAR), due to the system platforms' remarkable velocity difference and the forward-looking mode, the range cell migration (RCM) ...In the spaceborne/airborne forward-looking bistatic syn- thetic aperture radar (SA-FBSAR), due to the system platforms' remarkable velocity difference and the forward-looking mode, the range cell migration (RCM) not only depends on the target's two- dimensional location, but also varies with the range location non- linearly. And the nonlinearity is not just the slight deviation from the linear part, but exhibits evident nonlinear departure in the RCM trajectory. If the RCM is not properly corrected, nonlinear image distortions would occur. Based on the RCM model, a modified two-step RCM compensation (RCMC) method for SA-FBSAR is proposed. In this method, firstly the azimuth-dependent RCM is compensated by the scaling Fourier transform and the phase multi- plication. And then the range-dependent RCM is removed through interpolation. The effectiveness of the proposed RCMC method is verified by the simulation results of both point scatterers and area targets.展开更多
This issue of Asian Pacific Journal of Tropical Medicine has published a case report[1].This report detailed an atypical fatal case of fox-mediated human rabies.It once again reemphasized the importance of zoonotic di...This issue of Asian Pacific Journal of Tropical Medicine has published a case report[1].This report detailed an atypical fatal case of fox-mediated human rabies.It once again reemphasized the importance of zoonotic disease transmission by animals(including wildlife),and a need to look introspectively in order to consider innovative solutions aimed at reducing the burden of zoonoses.Rabies continues to significantly impact human lives.展开更多
Dear editor,A 76-year-old Chinese female presented by ambulance to the Emergency Department complaining of dizziness,headache and fatigue.Her son claimed that the patient“turned blue”three hours prior to onset of th...Dear editor,A 76-year-old Chinese female presented by ambulance to the Emergency Department complaining of dizziness,headache and fatigue.Her son claimed that the patient“turned blue”three hours prior to onset of the patient’s symptoms.Paramedics noted the patient’s SpO2 was 83%on room air with no improvement with a nonrebreather mask.Past medical history was signifi cant for diabetes and hypertension.Family,social and medication history were non-contributory.展开更多
BACKGROUND Permanent pacemaker implantation has the potential to impact left ventricular(LV)function and hence quality of life(QoL)in the long term.AIM To assess the effect of single-and dual-chamber pacing on LV func...BACKGROUND Permanent pacemaker implantation has the potential to impact left ventricular(LV)function and hence quality of life(QoL)in the long term.AIM To assess the effect of single-and dual-chamber pacing on LV function and QoL.METHODS This study included 56 patients who underwent permanent pacing:Dual pacing,dual sensing,dual responsive and rate responsive(DDDR)for the initial 3 months,ventricular sensing,inhibited response and rate responsive(VVIR)for the next 3 months,and DDDR mode for the last 3 months.Throughout the study period,various echocardiographic parameters,functional status,and QoL were measured to assess the impact of pacing on LV function compared with baseline and at every 3 months interval.RESULTS A significant change appeared in cardiac function after VVIR pacing which was in diastolic properties of LV as shown by increase in isovolumic relaxation time from(85.28±9.54 ms)to(89.53±9.65 ms).At the 3-,6-,and 9-month follow-up,reduction in LV ejection fraction was observed to be 62.71±4.66%,61.07±4.41%,and 58.48±3.89%,respectively.An increase in the QoL scores was noted at every follow-up visit.CONCLUSION An apparent depressant effect on LV function due to right ventricular pacing,with a higher incidence of adverse outcomes in the VVIR mode.In addition,an upsurge in QoL scores for the study population was noted,which indicates improvement in the QoL of patients post-pacing,irrespective of the mode.Generally,the DDDR mode is a highly preferable pacing mode.展开更多
In this paper, a new traffic flow model called the forward-backward velocity difference (FBVD) model based on the full velocity difference model is proposed to investigate the backward-looking effect by applying a mod...In this paper, a new traffic flow model called the forward-backward velocity difference (FBVD) model based on the full velocity difference model is proposed to investigate the backward-looking effect by applying a modified backward optimal velocity using generalized backward maximum speed. The FBVD model belongs to the family of microscopic models that consider spatiotemporally continuous formulations. Neutral stability conditions of the discrete car-following model are derived using the linear stability theory. The stability analysis results prove that the modified backward optimal velocity has a significant positive effect in stabilizing the traffic flow. Through nonlinear analysis, a kink-antikink solution is derived from the modified Korteweg-de Vries equation of the FBVD model to explain traffic congestion of the model. The validity of this theoretical model is checked using numerical results, according to which traffic jams were found to have been significantly diminished by the introduction of the modified backward optimal velocity.展开更多
An optimai current lattice model with backward-looking effect is proposed to describe the motion of traffic flow on a single lane highway. The behavior of the new model is investigated anaiytically and numerically. Th...An optimai current lattice model with backward-looking effect is proposed to describe the motion of traffic flow on a single lane highway. The behavior of the new model is investigated anaiytically and numerically. The stability, neutrai stability, and instability conditions of the uniform flow are obtained by the use of linear stability theory. The stability of the uniform flow is strengthened effectively by the introduction of the backward-looking effect. The numerical simulations are carried out to verify the validity of the new model. The outcomes of the simulation are corresponding to the linearly analyticai results. The analytical and numerical results show that the performance of the new model is better than that of the previous models.展开更多
文摘Exchanges and mutual learning between the Chinese and foreign civilizations are an important part of human cultural development.The Chinese civilization adopts an all-embracing,open and inclusive attitude to understand the different views of different civilizations on the connotation of values.The ancient Silk Road has opened a new window of friendship between countries and written a new chapter in the development of mankind.
文摘At the beginning of 2017,on behalf of the Editorial Board of Green Energy&Environment(GEE),we wish all of our readers,authors and reviewers a very happy and successful2017.Looking back to 2016,GEE has received many submissions from many countries all over the world since it was launched in April 2016.In the former three issues published,we remain committed to delivering those articles which should be
基金Supported by the National Natural Science Foundation of China General Programs(Nos.61072112,61372186)the National Natural Science Foundation of China Key Program(No.60890071)
文摘Downward Looking Sparse Linear Array Three Dimensional SAR(DLSLA 3D SAR) is an important form of 3D SAR imaging, which has a widespread application field. Since its practical equivalent phase centers are usually distributed sparsely and nonuniformly, traditional 3D SAR algorithms suffer from low resolution and high sidelobes in cross-track dimension. To deal with this problem, this paper introduces a method based on back-projection and convex optimization to achieve 3D high accuracy imaging reconstruction. Compared with traditional SAR algorithms, the proposed method sufficiently utilizes the sparsity of the 3D SAR imaging scene and can achieve lower sidelobes and higher resolution in cross-track dimension. In the simulated experiments, the reconstructed results of both simple and complex imaging scene verify that the proposed method outperforms 3D back-projection algorithm and shows satisfying cross-track dimensional resolution and good robustness to noise.
基金supported by UK Aid to the Future Health Systems Consortium,ESRC grant ES/N00759X/1 and MRC grant MR/S014934/1.
文摘China’s engagement in global affairs has changed substantially in the 2010s.One aspect of the country’s global reorientation has been its increased interest in,and willingness to play a role in,global health.In the early 2010s,the UK Department for International Development(DFID)initiated a collaboration with the Chinese government on a programme to support the country to play a greater and more effective global role in health and explore how the UK and China could work together on issues of key concern and contribute to improved global development outcomes.The programme worked with key Chinese agencies to carry out capacity building,support analysis of China’s approaches to engagement in global health governance and assistance,and provide support to government decision making.It also trialled several small-scale interventions in third countries through which Chinese agencies gained experience of working on health programmes overseas.The article reports on the main findings of an evaluation commissioned by DFID to learn from the programme.The programme provided support at a key time in China’s global reorientation;however,there is a need for continued development of capacity and systems for China to play the role envisaged by the country’s leadership.There is also a need for continued exploration on the part of China and partners of how to effectively collaborate to support improved global outcomes.
基金Supported by the National Natural Science Foundation of China(51009040)National Defence Key Laboratory of Autonomous Underwater Vehicle Technology(2008002)Scientific Service Special Funds of University in China(E091002)
文摘A method of underwater simultaneous localization and mapping (SLAM) based on forward-looking sonar was proposed in this paper. Positions of objects were obtained by the forward-looking sonar, and an improved association method based on an ant colony algorithm was introduced to estimate the positions. In order to improve the precision of the positions, the extended Kalman filter (EKF) was adopted. The presented algorithm was tested in a tank, and the maximum estimation error of SLAM gained was 0.25 m. The tests verify that this method can maintain better association efficiency and reduce navigatioJ~ error.
文摘BACKGROUND Left bundle branch pacing(LBBP)is a novel pacing modality of cardiac resynchronization therapy(CRT)that achieves more physiologic native ventricular activation than biventricular pacing(BiVP).AIM To explore the validity of electromechanical resynchronization,clinical and echocardiographic response of LBBP-CRT.METHODS Systematic review and Meta-analysis were conducted in accordance with the standard guidelines as mentioned in detail in the methodology section.RESULTS In our analysis,the success rate of LBBP-CRT was determined to be 91.1%.LBBP CRT significantly shortened QRS duration,with significant improvement in echocardiographic parameters,including left ventricular ejection fraction,left ventricular end-diastolic diameter and left ventricular end-systolic diameter in comparison with BiVP-CRT.CONCLUSION A significant reduction in New York Heart Association class and B-type natriuretic peptide levels was also observed in the LBBP-CRT group vs BiVP-CRT group.Lastly,the LBBP-CRT cohort had a reduced pacing threshold at follow-up as compared to BiVP-CRT.
文摘1.Through the construction during the last fourty years andespecially under the guidance of the“Reform and opening”policy,the power generation equipment manufacturing industry of Chinahas achieved tremendous development in the 1980’s.Whatever
基金Supported by the National Natural Science Foundation of China (No. 61071165)the Aviation Science Foundation (No. 20102052024)
文摘The bistatic Synthetic Aperture Radar (SAR) systems with separate transmitter and receiver antennas provide a new potential to imaging in the forward-looking geometry. Analysis of the Doppler property in this paper indicates the feasibility of Bistatic Forward-Looking (BFL) SAR imaging. Considering the different Doppler property determined by the two platforms in BFL SAR, a new 2-D point target spectrum is derived in our study. Based on the spectrum, an imaging method is chosen for the configuration, and the point target simulation validates the analysis.
文摘The deleterious effects of long-term right ventricular pacing necessitated the search for alternative pacing sites which could prevent or alleviate pacinginduced cardiomyopathy.Until recently,biventricular pacing(BiVP)was the only modality which could mitigate or prevent pacing induced dysfunction.Further,BiVP could resynchronize the baseline electromechanical dssynchrony in heart failure and improve outcomes.However,the high non-response rate of around 20%-30%remains a major limitation.This non-response has been largely attributable to the direct non-physiological stimulation of the left ventricular myocardium bypassing the conduction system.To overcome this limitation,the concept of conduction system pacing(CSP)came up.Despite initial success of the first CSP via His bundle pacing(HBP),certain drawbacks including lead instability and dislodgements,steep learning curve and rapid battery depletion on many occasions prevented its widespread use for cardiac resynchronization therapy(CRT).Subsequently,CSP via left bundle branch-area pacing(LBBP)was developed in 2018,which over the last few years has shown efficacy comparable to BiVP-CRT in small observational studies.Further,its safety has also been well established and is largely free of the pitfalls of the HBP-CRT.In the recent metanalysis by Yasmin et al,comprising of 6 studies with 389 participants,LBBPCRT was superior to BiVP-CRT in terms of QRS duration,left ventricular ejection fraction,cardiac chamber dimensions,lead thresholds,and functional status amongst heart failure patients with left bundle branch block.However,there are important limitations of the study including the small overall numbers,inclusion of only a single small randomized controlled trial(RCT)and a small follow-up duration.Further,the entire study population analyzed was from China which makes generalizability a concern.Despite the concerns,the meta-analysis adds to the growing body of evidence demonstrating the efficacy of LBBP-CRT.At this stage,one must acknowledge that the fact that still our opinions on this technique are largely based on observational data and there is a dire need for larger RCTs to ascertain the position of LBBPCRT in management of heart failure patients with left bundle branch block.
基金Supported by Education Department of Hunan Province Project (09C201)Hunan Provincial Natural Science Foundation of China (10jj6091) Planned Science and Technology Project of Hunan Province (2010FJ6015)
文摘The clutter direction-Doppler curves are not aligned on the near range bins for forward looking airborne radar. As a result, the performance of clutter suppression by Space-Time Adaptive Processing (STAP) degrades greatly because of the clutter range dependence. To deal with this problem, a new compensated method is proposed in this paper. The method rebuilds the clutter covariance matrix based on spatial high resolution Minimum Variance Distortionless Response (MVDR) spectrum, and then finds a matrix to transform the covariance matrix of short-range gate to the referred far-range gate. The method can compensate the clutter range dependence well. The simulation results show validity of the method.
基金supported by the Key Army Pre-research Projects of China(30107030803)
文摘Aiming at a novel missile-borne detector in the optional burst height proximity fuze, a self-adaptive high-resolution forward-looking imaging algorithm (SAHRFL-IA) is presented. The echo data are captured by the missile-borne detector in the target regions;thereby the azimuth angulation accuracy at the same distance dimension is improved dynamically. Thus, azimuth information of the targets in the detection area may be obtained accurately. The proposed imaging algorithm breaks through the conventional misconception of merely using azimuth discrimination curves under ideal conditions during monopulse angulation. The real-time echo data from the target region are used to perform error correction for this discrimination curve, and finally the accuracy of the azimuth angulation may reach the optimum at the same distance dimension. A series of experiments demonstrate the validity, reliability and high performance of the proposed imaging algorithm. Azimuth angulation accuracy may reach ten times that of the detection beam width. Meanwhile, the running time of this algorithm satisfies the requirements of missile-borne platforms.
基金Support by the National Natural Science Foundation of China(No.60736009 and No.60825104)
文摘When the Airborne Early Warning(AEW) radar transmits medial or high Pulse Repetitive Frequency(PRF) signal,the range ambiguity occurs.The clutter of short-range clutter has serious range dependence problem for non-Side Looking Airborne Radar(non-SLAR).As a result,the clutter plus noise covariance matrix can not be estimated correctly,and the performance of clutter suppression obtained by Space-Time Adaptive Processing(STAP) degrades greatly.The uniform linear array has not elevation degrees;therefore,the short-range clutter can not be suppressed directly.A short-range clutter suppression method is proposed.The method first estimate the elevation angles of the ambiguous short-range gate,then eliminates short-range clutter by space time interpolation and adds moving target protection in the procedure.This method can suppress the short-range clutter well.Simulation results show the validity of the method.
基金supported by the National Natural Science Foundation of China (61102143)the Fundamentl Research Funds for the Central Universities (ZYGX2011x003)
文摘In the spaceborne/airborne forward-looking bistatic syn- thetic aperture radar (SA-FBSAR), due to the system platforms' remarkable velocity difference and the forward-looking mode, the range cell migration (RCM) not only depends on the target's two- dimensional location, but also varies with the range location non- linearly. And the nonlinearity is not just the slight deviation from the linear part, but exhibits evident nonlinear departure in the RCM trajectory. If the RCM is not properly corrected, nonlinear image distortions would occur. Based on the RCM model, a modified two-step RCM compensation (RCMC) method for SA-FBSAR is proposed. In this method, firstly the azimuth-dependent RCM is compensated by the scaling Fourier transform and the phase multi- plication. And then the range-dependent RCM is removed through interpolation. The effectiveness of the proposed RCMC method is verified by the simulation results of both point scatterers and area targets.
文摘This issue of Asian Pacific Journal of Tropical Medicine has published a case report[1].This report detailed an atypical fatal case of fox-mediated human rabies.It once again reemphasized the importance of zoonotic disease transmission by animals(including wildlife),and a need to look introspectively in order to consider innovative solutions aimed at reducing the burden of zoonoses.Rabies continues to significantly impact human lives.
文摘Dear editor,A 76-year-old Chinese female presented by ambulance to the Emergency Department complaining of dizziness,headache and fatigue.Her son claimed that the patient“turned blue”three hours prior to onset of the patient’s symptoms.Paramedics noted the patient’s SpO2 was 83%on room air with no improvement with a nonrebreather mask.Past medical history was signifi cant for diabetes and hypertension.Family,social and medication history were non-contributory.
文摘BACKGROUND Permanent pacemaker implantation has the potential to impact left ventricular(LV)function and hence quality of life(QoL)in the long term.AIM To assess the effect of single-and dual-chamber pacing on LV function and QoL.METHODS This study included 56 patients who underwent permanent pacing:Dual pacing,dual sensing,dual responsive and rate responsive(DDDR)for the initial 3 months,ventricular sensing,inhibited response and rate responsive(VVIR)for the next 3 months,and DDDR mode for the last 3 months.Throughout the study period,various echocardiographic parameters,functional status,and QoL were measured to assess the impact of pacing on LV function compared with baseline and at every 3 months interval.RESULTS A significant change appeared in cardiac function after VVIR pacing which was in diastolic properties of LV as shown by increase in isovolumic relaxation time from(85.28±9.54 ms)to(89.53±9.65 ms).At the 3-,6-,and 9-month follow-up,reduction in LV ejection fraction was observed to be 62.71±4.66%,61.07±4.41%,and 58.48±3.89%,respectively.An increase in the QoL scores was noted at every follow-up visit.CONCLUSION An apparent depressant effect on LV function due to right ventricular pacing,with a higher incidence of adverse outcomes in the VVIR mode.In addition,an upsurge in QoL scores for the study population was noted,which indicates improvement in the QoL of patients post-pacing,irrespective of the mode.Generally,the DDDR mode is a highly preferable pacing mode.
文摘In this paper, a new traffic flow model called the forward-backward velocity difference (FBVD) model based on the full velocity difference model is proposed to investigate the backward-looking effect by applying a modified backward optimal velocity using generalized backward maximum speed. The FBVD model belongs to the family of microscopic models that consider spatiotemporally continuous formulations. Neutral stability conditions of the discrete car-following model are derived using the linear stability theory. The stability analysis results prove that the modified backward optimal velocity has a significant positive effect in stabilizing the traffic flow. Through nonlinear analysis, a kink-antikink solution is derived from the modified Korteweg-de Vries equation of the FBVD model to explain traffic congestion of the model. The validity of this theoretical model is checked using numerical results, according to which traffic jams were found to have been significantly diminished by the introduction of the modified backward optimal velocity.
基金National Natural Science Foundation of China under Grant No.60674062Middle-Aged and Young Scientists Research Incentive Fund of Shandong Province under Grant No.2007BS01013
文摘An optimai current lattice model with backward-looking effect is proposed to describe the motion of traffic flow on a single lane highway. The behavior of the new model is investigated anaiytically and numerically. The stability, neutrai stability, and instability conditions of the uniform flow are obtained by the use of linear stability theory. The stability of the uniform flow is strengthened effectively by the introduction of the backward-looking effect. The numerical simulations are carried out to verify the validity of the new model. The outcomes of the simulation are corresponding to the linearly analyticai results. The analytical and numerical results show that the performance of the new model is better than that of the previous models.