A high-density, high-flux circulating fluidized bed （CFB） riser （100 mm in ID and 10.614 m in height） was ap- plied in a wide range of operating conditions （with solid fluxes up to 400 kg/m2s and superficial gas ...A high-density, high-flux circulating fluidized bed （CFB） riser （100 mm in ID and 10.614 m in height） was ap- plied in a wide range of operating conditions （with solid fluxes up to 400 kg/m2s and superficial gas velocities up to 12 m/s） to examine its radial non-uniformity dynamics. The solids holdup was determined through the use of a fiber-optic probe at 11 axial levels. The results indicated that under all operating conditions, the high superficial gas velocity and low solid flux- es maintained a low radial non-uniformity index （RNI）. The high-density/flux CFB riser had several unique characteristics, so that the peak of the radial solids holdup profile occurred at a position with r/R=0.8. The RNI and solids holdup at the cross-sectional position had a good logarithmic relationship at the low-density condition （with a mean solids holdup of 〈0.2）, and the RNI decreased when the mean solids holdup exceeded 0.2. Investigation of the dynamics of stratified injec- tion revealed that the feed ratio had an important effect on G, and on solids holdup distribution. A novel ＂〈＂ shaped axial solids holdup profile was found. Gs decreased sharply when the up-flow feed ratio exceeded 0.5, and RNI was lowest when the up-flow feed ratio was 1.展开更多
维护道路交叉口信息的现势性和完整性是城市道路地图生产和更新的关键环节。针对众源轨迹数据存在的时空异质性和密度分布不均等问题,提出了一种道路交叉口层次化提取方法。首先对原始轨迹数据进行自适应密度匀化处理;然后结合车辆轨迹...维护道路交叉口信息的现势性和完整性是城市道路地图生产和更新的关键环节。针对众源轨迹数据存在的时空异质性和密度分布不均等问题,提出了一种道路交叉口层次化提取方法。首先对原始轨迹数据进行自适应密度匀化处理;然后结合车辆轨迹方向、速度变化与转弯距离比等多维特征提取交叉口轨迹;再借助具有噪声的基于密度的空间聚类(density-based spatial clustering of applications with noise,DBSCAN)算法将交叉口轨迹聚类为不同交叉口目标,进而通过轨迹起始点航向编码进行交叉口内部通行模式提取;最后利用分段轨迹迭代连接方法提取交叉口骨架结构。结果表明,该方法能准确完整地提取不同形状、不同尺度的道路交叉口结构,提取精度和效率较密度匀化前有较大提升。展开更多
In this paper, a novel soft reliability-based iterative majority-logic decoding algorithm with uniform quantization is proposed for regularly structured low density parity-check(LDPC) codes. A weighted measure is intr...In this paper, a novel soft reliability-based iterative majority-logic decoding algorithm with uniform quantization is proposed for regularly structured low density parity-check(LDPC) codes. A weighted measure is introduced for each check-sum of the parity-check matrix and a scaling factor is used to weaken the overestimation of extrinsic information. Furthermore, the updating process of the reliability measure takes advantage of turbo-like iterative decoding strategy. The main computational complexity of the proposed algorithm only includes logical and integer operations with the bit uniform quantization criterion. Simulation results show that the novel decoding algorithm can achieve excellent error-correction performance and a fast decoding convergence speed.展开更多
基金the financial support of the National Program on Key Basic Research Project (973 Program) of China (no. 2012CB215000)
文摘A high-density, high-flux circulating fluidized bed （CFB） riser （100 mm in ID and 10.614 m in height） was ap- plied in a wide range of operating conditions （with solid fluxes up to 400 kg/m2s and superficial gas velocities up to 12 m/s） to examine its radial non-uniformity dynamics. The solids holdup was determined through the use of a fiber-optic probe at 11 axial levels. The results indicated that under all operating conditions, the high superficial gas velocity and low solid flux- es maintained a low radial non-uniformity index （RNI）. The high-density/flux CFB riser had several unique characteristics, so that the peak of the radial solids holdup profile occurred at a position with r/R=0.8. The RNI and solids holdup at the cross-sectional position had a good logarithmic relationship at the low-density condition （with a mean solids holdup of 〈0.2）, and the RNI decreased when the mean solids holdup exceeded 0.2. Investigation of the dynamics of stratified injec- tion revealed that the feed ratio had an important effect on G, and on solids holdup distribution. A novel ＂〈＂ shaped axial solids holdup profile was found. Gs decreased sharply when the up-flow feed ratio exceeded 0.5, and RNI was lowest when the up-flow feed ratio was 1.
文摘维护道路交叉口信息的现势性和完整性是城市道路地图生产和更新的关键环节。针对众源轨迹数据存在的时空异质性和密度分布不均等问题,提出了一种道路交叉口层次化提取方法。首先对原始轨迹数据进行自适应密度匀化处理;然后结合车辆轨迹方向、速度变化与转弯距离比等多维特征提取交叉口轨迹;再借助具有噪声的基于密度的空间聚类(density-based spatial clustering of applications with noise,DBSCAN)算法将交叉口轨迹聚类为不同交叉口目标,进而通过轨迹起始点航向编码进行交叉口内部通行模式提取;最后利用分段轨迹迭代连接方法提取交叉口骨架结构。结果表明,该方法能准确完整地提取不同形状、不同尺度的道路交叉口结构,提取精度和效率较密度匀化前有较大提升。
基金supported by the National Natural Science Foundation of China(Nos.61472464,61671091 and 61471075)the Natural Science Foundation of Chongqing Science and Technology Commission(No.cstc2015jcyj A0554)+1 种基金the Program for Innovation Team Building at Institutions of Higher Education in Chongqing(No.J2013-46)the Undergraduate Science Research Training Project for Chongqing University of Posts and Telecommunications(No.A2016-61)
文摘In this paper, a novel soft reliability-based iterative majority-logic decoding algorithm with uniform quantization is proposed for regularly structured low density parity-check(LDPC) codes. A weighted measure is introduced for each check-sum of the parity-check matrix and a scaling factor is used to weaken the overestimation of extrinsic information. Furthermore, the updating process of the reliability measure takes advantage of turbo-like iterative decoding strategy. The main computational complexity of the proposed algorithm only includes logical and integer operations with the bit uniform quantization criterion. Simulation results show that the novel decoding algorithm can achieve excellent error-correction performance and a fast decoding convergence speed.
