[en] The wall drag model in the TRAC/RELAP5 Advanced Computational Engine computer code (TRACE) has certain known deficiencies. For example, in an annular flow regime, the code predicts an unphysical high liquid velocity compared to the experimental data. To address those deficiencies, a new wall frictional drag package has been developed and implemented in the TRACE code to model the wall drag for two-phase flow system code. The modeled flow regimes are (1) annular/mist, (2) bubbly/slug, and (3) bubbly/slug with wall nucleation. The new models use void fraction (instead of flow quality) as the correlating variable to minimize the calculation oscillation. In addition, the models allow for transitions between the three regimes. The annular/mist regime is subdivided into three separate regimes for pure annular flow, annular flow with entrainment, and film breakdown. For adiabatic two-phase bubbly/slug flows, the vapor phase primarily exists outside of the boundary layer, and the wall shear uses single-phase liquid velocity for friction calculation. The vapor phase wall friction drag is set to zero for bubbly/slug flows. For bubbly/slug flows with wall nucleation, the bubbles are presented within the hydrodynamic boundary layer, and the two-phase wall friction drag is significantly higher with a pronounced mass flux effect. An empirical correlation has been studied and applied to account for nucleate boiling. Verification and validation tests have been performed, and the test results showed a significant code improvement. (authors)

[en] Among the various micro-pump actuation devices, piezoelectric composite laminate actuation has become an effective method. Due to lacking of analysis treatments, the design of this type micro-pump is in a great limitation. In this paper, an electromechanical-coupled mechanics model is established for the circle-flake micro-actuator. A kind of analysis and design method is presented that piezoelectric plate's radial strain induced by inverse piezoelectric effect is equivalently substituted with transverse stress on piezoelectric composite laminates. It is pointed out that the equivalent transverse load depends on the edge electric field distribution of parallel plate capacitor. The question has been solved that where the neutral plane in the piezoelectric composite laminates lies. Finally, an optimization design is developed on the radius ratio of piezoelectric-to-silicon plate radius by utilizing of FEA modeling

[en] Percutaneous transluminal coronary angioplasty (PTCA) is the most common technique for the restenosis of coronary arteries. Restenosis, Which is an unsolved clinical problem occurs within 6 months in 40%-60% of all cases. At present, endovascular irradiation with radioisotope is a promising method to overcome restenosis. The author mainly discusses the mechanism, doses, animal and clinical experiments and safety of intravascular brachytherapy. It is a review of relatively recently developed field of this technique

[en] A new counting rate measurement and protection system used in research reactor was developed by utilizing new frequency /voltage transform method and SCM technology. The system has the characteristics such as fast response speed, highly automatic level, accurate measurement and reliable protection. The system has operated steadily on a research reactor for two years. (authors)

[en] The methods of the location of single photon are studied systematically. The methods of the performance analysis and the engineering design of weighting location are presented. A new method of high resolution location is proposed to overcome the shortcomings of weighting location

[en] This paper described the basic principle of a new method in bone density measurement, i.e. the dual energy X ray absorptiometry, and presented the calculating formula for bone quality and structure diagram for implementing this method

[en] Compared to traditional large reactors, small modular reactors have advantages to attract utilities around the world in recent years. These advantages include shorter construction schedule and lower cost, lower risk of design basis events and more applicable passive systems. NuScale is the first license application among small modular reactors submitted to Nuclear Regulatory Commission for design certification. In the novel design, some unique thermal hydraulic phenomena are involved in the operational and accidental scenarios, e.g., high-pressure condensation, helical coil heat transfer and natural circulation in power operation. These phenomena are critical to the nuclear safety and thus require in-depth evaluation by the applicant. To support regulatory decision, NRC TRACE confirmatory analyses becomes indispensable. In this paper, the NRC TRACE confirmatory model development and validation for NuScale design are presented. Experimental separate effect tests and integral effect tests were used to benchmark the TRACE models. The goal was to prepare a plant model to support regulatory decision making. Model development strategy, assumptions, and high-level assessment results are reported to the maximum extent that complies with the requirement to withhold proprietary information. (author)

[en] This paper introduces the research and development of the SPECT and its imaging research, the basic parts, performances and clinical software in the newly researched and developed SPECT system. Some suggestions on further improvement upon the resolution and sensitivity of the SPECT and application in the computer simulation in the SPECT researches are also made for improving the quality of SPECT imaging

[en] A brief introduction is given to the recent development in the design of SPECT collimator geometry and its corresponding reconstruction algorithms. Moreover, some hot points of recent studies on SPECT image reconstruction problem are reviewed

[en] The stimulation effect that some beneficial agronomic qualities have exhibited in present-generation plants have also been observed due to ion implantation on plants. However, there is relatively little knowledge regarding the molecular mechanism of the stimulation effects of ion-beam implantation. In order to extend our current knowledge about the functional genes related to this stimulation effect, we have reported a comprehensive microarray analysis of the transcriptome features of the promoted-growth rice seedlings germinating from seeds implanted by a low-energy N⁺ beam. The results showed that 351 up-regulated transcripts and 470 down-regulated transcripts, including signaling proteins, kinases, plant hormones, transposable elements, transcription factors, non-coding protein RNA (including miRNA), secondary metabolites, resistance proteins, peroxidase and chromatin modification, are all involved in the stimulating effects of ion-beam implantation. The divergences of the functional catalog between the vacuum and ion implantation suggest that ion implantation is the principle cause of the ion-beam implantation biological effects, and revealed the complex molecular networks required to adapt to ion-beam implantation stress in plants, including enhanced transposition of transposable elements, promoted ABA biosynthesis and changes in chromatin modification. Our data will extend the current understanding of the molecular mechanisms and gene regulation of stimulation effects. Further research on the candidates reported in this study should provide new insights into the molecular mechanisms of biological effects induced by ion-beam implantation. (author)