This paper reports that Coulomb explosions taken place in the experiment of heteronuclear deuterated methane clusters （（CD4）n） in a gas jet subjected to intense femtoseeond laser pulses （170 mJ, 70 fs） have led ...This paper reports that Coulomb explosions taken place in the experiment of heteronuclear deuterated methane clusters （（CD4）n） in a gas jet subjected to intense femtoseeond laser pulses （170 mJ, 70 fs） have led to table-top laser driven DD nuclear fusion. The clusters produced in supersonic expansion had an average size of about 5 nm in radius and the laser intensity used was 3 × 10^17 W/cm^2.The measured maximum and average energies of deuterons produced in the laser-cluster interaction were 60 and 13.5 keV, respectively. Prom DD collisions of energetic deuterons, a yield of 2.5（±0.4） × 10^4 fusion neutrons of 2.45 MeV per shot was realized, giving rise to a neutron production efficiency of about 1.5 × 10^5 per joule of incident laser pulse energy. Theoretical calculations were performed and a fairly good agreement of the calculated neutron yield with that obtained from the present experiment was found.展开更多
Multi-laser-target tracking is an important subject in the field of signal processing of laser warners. A clustering method is applied to the measurement of laser warner, and the space-time fusion for measurements in ...Multi-laser-target tracking is an important subject in the field of signal processing of laser warners. A clustering method is applied to the measurement of laser warner, and the space-time fusion for measurements in the same cluster is accomplished. Real-time tracking of multi-laser-target and real-time picking of multi-laser-signal are introduced using data fusion of the measurements. A prototype device of the algorithm is built up. The results of experiments show that the algorithm is very effective.展开更多
Neutrons （2.45MeV） from deuterium cluster fusion induced by the intense femtosecond （3Ors） laser pulse are experimentally demonstrated. The average neutron yield 103 per shot is obtained. It is found that the yiel...Neutrons （2.45MeV） from deuterium cluster fusion induced by the intense femtosecond （3Ors） laser pulse are experimentally demonstrated. The average neutron yield 103 per shot is obtained. It is found that the yield slightly increases with the increasing laser spot size. No neutron can be observed when the laser intensity I 〈 4.3 × 10^15 W/cm^2.展开更多
The effect of the laser spot size on the neutron yield of table-top nuclear fusion from explosions of a femtosecond intense laser pulse heated deuterium clusters is investigated by using a simplified model, in which t...The effect of the laser spot size on the neutron yield of table-top nuclear fusion from explosions of a femtosecond intense laser pulse heated deuterium clusters is investigated by using a simplified model, in which the cluster size distribution and the energy attenuation of the laser as it propagates through the cluster jet are taken into account. It has been found that there exists a proper laser spot size for the maximum fusion neutron yield for a given laser pulse and a specific deuterium gas cluster jet. The proper spot size, which is dependent on the laser parameters and the cluster jet parameters, has been calculated and compared with the available experimental data. A reasonable agreement between the calculated results and the published experimental results is found.展开更多
目前大多数视觉与激光融合的同步定位与建图(Simultaneous Localization and Mapping,SLAM)算法在进行位姿状态估计时,通常假设其运行环境为静态。然而,当机器人在包含动态对象的环境中移动时,这些对象的出现会改变图像信息,导致数据关...目前大多数视觉与激光融合的同步定位与建图(Simultaneous Localization and Mapping,SLAM)算法在进行位姿状态估计时,通常假设其运行环境为静态。然而,当机器人在包含动态对象的环境中移动时,这些对象的出现会改变图像信息,导致数据关联错误,从而引发SLAM定位误差。针对此问题,提出一种改进的视觉与激光融合SLAM算法,以提高室内动态环境下的三维建图精度和鲁棒性。该方法结合对极几何约束和欧式聚类,实现对动态对象的精准检测和剔除,减少动态对象对SLAM系统定位和建图的干扰。实验结果表明,相较于传统的融合SLAM方法,改进后的算法在动态环境下的定位精度、地图质量以及鲁棒性方面均有提升,为智能机器人、自动驾驶等领域的动态环境建图提供新的解决方案。展开更多
Image fusion should consider the priori knowledge of the source images to be fused, such as the characteristics of the images and the goal of image fusion, that is to say, the knowledge about the input data and the ap...Image fusion should consider the priori knowledge of the source images to be fused, such as the characteristics of the images and the goal of image fusion, that is to say, the knowledge about the input data and the application plays a crucial role. This paper is concerned on multiresolution （MR） image fusion. Considering the characteristics of the multisensor （SAR and FLIR etc） and the goal of fusion, which is to achieve one image in possession of the contours feature and the target region feature. It seems more meaningful to combine features rather than pixels. A multisensor image fusion scheme based on K-means duster and steerable pyramid is presented. K-means cluster is used to segment out objects in FLIR images. The steerable pyramid is a multiresolution analysis method, which has a good property to extract contours information at different scales, Comparisons are made with the relevant existing techniques in the literature. The paper concludes with some examples to illustrate the efficiency of the proposed scheme.展开更多
基金supported by the National Basic Research Program of China (Grant No 2006CB806000)the National Natural Science Foundation of China (Grant No 10535070)
文摘This paper reports that Coulomb explosions taken place in the experiment of heteronuclear deuterated methane clusters （（CD4）n） in a gas jet subjected to intense femtoseeond laser pulses （170 mJ, 70 fs） have led to table-top laser driven DD nuclear fusion. The clusters produced in supersonic expansion had an average size of about 5 nm in radius and the laser intensity used was 3 × 10^17 W/cm^2.The measured maximum and average energies of deuterons produced in the laser-cluster interaction were 60 and 13.5 keV, respectively. Prom DD collisions of energetic deuterons, a yield of 2.5（±0.4） × 10^4 fusion neutrons of 2.45 MeV per shot was realized, giving rise to a neutron production efficiency of about 1.5 × 10^5 per joule of incident laser pulse energy. Theoretical calculations were performed and a fairly good agreement of the calculated neutron yield with that obtained from the present experiment was found.
基金University Doctor Subject Foundation of China (20060699024)
文摘Multi-laser-target tracking is an important subject in the field of signal processing of laser warners. A clustering method is applied to the measurement of laser warner, and the space-time fusion for measurements in the same cluster is accomplished. Real-time tracking of multi-laser-target and real-time picking of multi-laser-signal are introduced using data fusion of the measurements. A prototype device of the algorithm is built up. The results of experiments show that the algorithm is very effective.
基金Supported by National Natural Science Foundation of China （60874063）, and Innovation and Scientific Research Foundation of Graduate Student of Heilongjiang Province （YJSCX2012-263HLJ）
基金Supported by the National Natural Science Foundation of China under Grant No 10535030, and the Key Foundation of China Academy of Engineering Physics under Grant No 2006Z0202.
文摘Neutrons （2.45MeV） from deuterium cluster fusion induced by the intense femtosecond （3Ors） laser pulse are experimentally demonstrated. The average neutron yield 103 per shot is obtained. It is found that the yield slightly increases with the increasing laser spot size. No neutron can be observed when the laser intensity I 〈 4.3 × 10^15 W/cm^2.
基金Project supported by the National Basic Research Program of China (Grant No 2006CB806000)the National Natural Science Foundation of China (Grant No 10535070)
文摘The effect of the laser spot size on the neutron yield of table-top nuclear fusion from explosions of a femtosecond intense laser pulse heated deuterium clusters is investigated by using a simplified model, in which the cluster size distribution and the energy attenuation of the laser as it propagates through the cluster jet are taken into account. It has been found that there exists a proper laser spot size for the maximum fusion neutron yield for a given laser pulse and a specific deuterium gas cluster jet. The proper spot size, which is dependent on the laser parameters and the cluster jet parameters, has been calculated and compared with the available experimental data. A reasonable agreement between the calculated results and the published experimental results is found.
文摘目前大多数视觉与激光融合的同步定位与建图(Simultaneous Localization and Mapping,SLAM)算法在进行位姿状态估计时,通常假设其运行环境为静态。然而,当机器人在包含动态对象的环境中移动时,这些对象的出现会改变图像信息,导致数据关联错误,从而引发SLAM定位误差。针对此问题,提出一种改进的视觉与激光融合SLAM算法,以提高室内动态环境下的三维建图精度和鲁棒性。该方法结合对极几何约束和欧式聚类,实现对动态对象的精准检测和剔除,减少动态对象对SLAM系统定位和建图的干扰。实验结果表明,相较于传统的融合SLAM方法,改进后的算法在动态环境下的定位精度、地图质量以及鲁棒性方面均有提升,为智能机器人、自动驾驶等领域的动态环境建图提供新的解决方案。
基金This project was supported by National "863" High Technology Research and Development Program of China(2001AA135091) National Science Foundation of China +2 种基金Shanghai Key Scientific Project (02DZ15001) China PH.D. DisciplineSpecial Foundation (20020248029) China Aviation Science Foundation (02D57003) .
文摘Image fusion should consider the priori knowledge of the source images to be fused, such as the characteristics of the images and the goal of image fusion, that is to say, the knowledge about the input data and the application plays a crucial role. This paper is concerned on multiresolution （MR） image fusion. Considering the characteristics of the multisensor （SAR and FLIR etc） and the goal of fusion, which is to achieve one image in possession of the contours feature and the target region feature. It seems more meaningful to combine features rather than pixels. A multisensor image fusion scheme based on K-means duster and steerable pyramid is presented. K-means cluster is used to segment out objects in FLIR images. The steerable pyramid is a multiresolution analysis method, which has a good property to extract contours information at different scales, Comparisons are made with the relevant existing techniques in the literature. The paper concludes with some examples to illustrate the efficiency of the proposed scheme.
