分类: 动力与电气工程 >> 工程热物理学 提交时间: 2017-06-22 合作期刊: 《热科学学报》
摘要: In order to investigate the effects of probe support on the stall characteristics of micro compressors, an experiment was carried out on a large-scale low-speed research compressor according to the principle of geometric similarity. A cylindrical probe support intruding to 50% blade span was mounted at 50% chord upstream from the rotor blade leading edge. The static pressure rise characteristic of the compressor is measured, with and without the probe support respectively. The dynamic compressor behavior from pre-stall to full stall was also measured. The results indicate that the stability margin of the compressor is lowered after installing the probe support. The stall inception is aroused by modal wave disturbances. The disturbances developed into two stall cells smoothly before installing the probe support, while the disturbances first developed into a single stall cell then splitting into two stall cells after installing the probe support. The presence of probe support lowers the initial intensity of the rotating stall of the compressor, while it doesn't alter the intensity of the rotation stall after the compressor enters into full stall.
分类: 核科学技术 >> 粒子加速器 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: An ion beam analysis system was established on a 1.7 MV tandem accelerator, enabling Rutherford backscattering (RBS), elastic recoil detection (ERD), nuclear reaction analysis (NRA) and channeling measurements. The system was tested by performing qualitative and quantitative analysis of Si, Ni/Si, BiFeO3:La/Si, MoC/Mo/Si and TiBN/Si samples. RBS of a BiFeO3:La film was used as system calibration. Tested by ion beam channeling, a Si(100) is of good crystallinity (min = 3.01%). For thin film samples, the measured thickness agrees well with simulation results by SIMNRA. In particular, composition of a MoC/Mo/Si and TiBN film samples were analyzed by RBS and non-Rutherford elastic backscattering.
分类: 地球科学 >> 地质学 提交时间: 2018-01-23 合作期刊: 《古脊椎动物学报》
摘要: The first clutch of Stalicoolithus shifengensis is described here. This incomplete dinosaur egg clutch in which three nearly complete eggs and two egg prints were preserved was discovered in the red deposits of the Sanshui Formation at a construction site near the sluice of North Village, Dali Town, Nanhai District, Foshan City, Guangdong Province, China. The eggs in the clutch are stacked with various ranges. Based on the characteristics of the eggshell, these eggs can be assigned to S. shifengensis. The discovery of S. shifengensis in the Sanshui Formation complements the clutch information about the oospecies as well as expands its paleogeographic distribution, and sets the foundation for discussing the diversity of dinosaur eggs in the Sanshui Basin.
分类: 核科学技术 >> 粒子加速器 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: An electrostatic accelerating column was designed and fabricated by Lanzhou University for an intense D-T/D-D neutron generator. In order to achieve a neutron yield of 5.0�1012 n/s, a deuteron beam of 30 mA, accelerated to 400 kV, and transported in the electrostatic accelerating column smoothly are required. One particle-in-cell code BEAMPATH was used to simulate the beam transport, and the IONB1.0 code was used to simulate the intense beam envelopes. Emittance growths due to space charge effect and spherical aberration were analyzed. The simulation results show that the accelerating column can transport deuteron beam of 30 mA smoothly and the requirement for the neutron generator is satisfied.