• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2002.05a
• /
• pp.161-166
• /
• 2002

The resent experimental study is focused on the application of multi-point simultaneous measurement by PIV Particle Image Velocimetry) to guide vane region within diffuser pump. Various different kinds of rotational veto ity and changing clearance between Guide Vane and Impeller were selected as experimental condition. Optimized ross correlation identification to obtain velocity vectors is implemented with direct calculation of correlation coeffi cients. Fine optical setup concerned with PW performance is arranged for the accurate PW measurement of high peed complex flow. Variable flow pattern are represented quantitatively at the stator region.

• Nuclear Engineering and Technology
• /
• v.52 no.10
• /
• pp.2361-2369
• /
• 2020

Compton cameras using large scintillators have been developed for high imaging sensitivity. These scintillator-based Compton cameras, however, mainly due to relatively low energy resolution, suffer from undesired background-radiation signals, especially when radioactive materials' activity is very low or their location is far from the Compton camera. To alleviate this problem for a large-size Compton camera, in the present study, a hybrid-type shielding system was designed that combines an active shield with a veto detector and a passive shield that surrounds the active shield. Then, the performance of the hybrid shielding system was predicted, by Monte Carlo radiation transport simulation using Geant4, in terms of minimum detectable activity (MDA), signal-to-noise ratio (SNR), and image resolution. Our simulation results show that, for the most cases, the hybrid shielding system significantly improves the performance of the large-size Compton camera. For the cases investigated in the present study, the use of the shielding system decreased the MDA by about 1.4, 1.6, and 1.3 times, increased the SNR by 1.2-1.9, 1.1-1.7, and 1.3-2.1 times, and improved the image resolution (i.e., reduced the FWHM) by 7-8, 1-6, and 3-5% for ¹³⁷Cs, ⁶⁰Co, and ¹³¹I point source located at 1-5 m from the imaging system, respectively.

• Korean Journal of Legislative Studies
• /
• v.15 no.2
• /
• pp.187-217
• /
• 2009

The purpose of this study is to analyze whether there is gender difference in Members' voting on women's issue bills, and to find out determinants of Members voting decisions on the same bills. The findings are as follows. First, there is no gender difference in women's issue voting, so women Members as a group were not significantly different from men Members in voting behavior. That's not because women Members were split in voting but because both men and women Members are very supportive of the bills. Secondly, Members' party and ideology play a significant role in Member' voting on women's issue. Compared to the majority party(Uri party)'s overwhelming support, minority parties are much less supportive on the issues. Member's ideology also proved to be important indicator of voting decision. The more ideologically liberal Members are, the more supportive of the bills.