A systematic method was developed for ice-class propeller modeling,performance estimation,strength and integrity evaluation and optimization.To estimate the impact of sea ice on the propeller structure,URI3 rules,esta...A systematic method was developed for ice-class propeller modeling,performance estimation,strength and integrity evaluation and optimization.To estimate the impact of sea ice on the propeller structure,URI3 rules,established by the International Association of Classification Societies in 2007,were applied for ice loading calculations.An R-class propeller(a type of ice-class propeller)was utilized for subsequent investigations.The propeller modeling was simplified based on a conventional method,which expedited the model building process.The propeller performance was simulated using the computational fluid dynamics(CFD)method.The simulation results were validated by comparison with experimental data.Furthermore,the hydrodynamic pressure was transferred into a finite element analysis(FEA)module for strength assessment of ice-class propellers.According to URI3 rules,the ice loading was estimated based on different polar classes and working cases.Then,the FEA method was utilized to evaluate the propeller strength.The validation showed that the simulation results accorded with recent research results.Finally,an improved optimization method was developed to save the propeller constituent materials.The optimized propeller example had a minimum safety factor of 1.55,satisfying the safety factor requirement of≥1.5,and reduced the design volume to 88.2%of the original.展开更多
In this article, we give an operator transform T （＊） from class A operator to the class of hyponormal operators. It is different from the operator transform T defined by M. Ch and T. Yamazaki. Then, we show that σ...In this article, we give an operator transform T （＊） from class A operator to the class of hyponormal operators. It is different from the operator transform T defined by M. Ch and T. Yamazaki. Then, we show that σ（T ） = σ（ T （＊）） and σa（T ）／{0} = σa（ T （＊））／{0}, in case T belongs to class A. Next, we obtain some relations between T and T （9）.展开更多
This paper presents a 1.8 GHz class-E controlled power amplifier (PA). The proposed power amplifier is designed with two-stage architecture. The main advantage of the proposed technique for output control power is a h...This paper presents a 1.8 GHz class-E controlled power amplifier (PA). The proposed power amplifier is designed with two-stage architecture. The main advantage of the proposed technique for output control power is a high 37 dB output power dynamic range with good average power adding efficiency. The measurement results show that the PA achieves a high power gain of 23 dBm and power added efficiency (PAE) by 38%. The circuit was post layout simulated in a standard 0.18 μm CMOS technology.展开更多
极地低温环境下,船体结构选材是极地船舶设计的关键环节。目前,各船级社船体结构选材规范要求既相互关联又存在差异,并且缺乏统一的设计温度定义,给极地低温环境下的船体结构选材设计带来较大挑战。通过对极地低温环境下船体结构选材规...极地低温环境下,船体结构选材是极地船舶设计的关键环节。目前,各船级社船体结构选材规范要求既相互关联又存在差异,并且缺乏统一的设计温度定义,给极地低温环境下的船体结构选材设计带来较大挑战。通过对极地低温环境下船体结构选材规范的系统梳理,按照规范基础和设计温度定义等方面的差异,可将其归纳为三大类,包括国际船级社协会统一要求S6(IACS UR S6)及船级社防寒规范、极地船级(POLAR CLASS)规范、俄罗斯船级社(RMRS)规范。文中对三大类规范之间的差异进行了对比分析,包括适用范围、设计温度和钢级选取等,提出有价值的结论和建议,以期为极地低温环境下船体结构选材设计提供参考。展开更多
基金The author would like to thank University of Tasmania and Newcastle University for their support。
文摘A systematic method was developed for ice-class propeller modeling,performance estimation,strength and integrity evaluation and optimization.To estimate the impact of sea ice on the propeller structure,URI3 rules,established by the International Association of Classification Societies in 2007,were applied for ice loading calculations.An R-class propeller(a type of ice-class propeller)was utilized for subsequent investigations.The propeller modeling was simplified based on a conventional method,which expedited the model building process.The propeller performance was simulated using the computational fluid dynamics(CFD)method.The simulation results were validated by comparison with experimental data.Furthermore,the hydrodynamic pressure was transferred into a finite element analysis(FEA)module for strength assessment of ice-class propellers.According to URI3 rules,the ice loading was estimated based on different polar classes and working cases.Then,the FEA method was utilized to evaluate the propeller strength.The validation showed that the simulation results accorded with recent research results.Finally,an improved optimization method was developed to save the propeller constituent materials.The optimized propeller example had a minimum safety factor of 1.55,satisfying the safety factor requirement of≥1.5,and reduced the design volume to 88.2%of the original.
基金supported by Science Foundation of Ministry of Education of China (208081)Technology and pioneering project in Henan Provice (102300410012)Education Foundation of Henan Province (2007110016, 2008B110006)
文摘In this article, we give an operator transform T （＊） from class A operator to the class of hyponormal operators. It is different from the operator transform T defined by M. Ch and T. Yamazaki. Then, we show that σ（T ） = σ（ T （＊）） and σa（T ）／{0} = σa（ T （＊））／{0}, in case T belongs to class A. Next, we obtain some relations between T and T （9）.
文摘This paper presents a 1.8 GHz class-E controlled power amplifier (PA). The proposed power amplifier is designed with two-stage architecture. The main advantage of the proposed technique for output control power is a high 37 dB output power dynamic range with good average power adding efficiency. The measurement results show that the PA achieves a high power gain of 23 dBm and power added efficiency (PAE) by 38%. The circuit was post layout simulated in a standard 0.18 μm CMOS technology.
文摘极地低温环境下,船体结构选材是极地船舶设计的关键环节。目前,各船级社船体结构选材规范要求既相互关联又存在差异,并且缺乏统一的设计温度定义,给极地低温环境下的船体结构选材设计带来较大挑战。通过对极地低温环境下船体结构选材规范的系统梳理,按照规范基础和设计温度定义等方面的差异,可将其归纳为三大类,包括国际船级社协会统一要求S6(IACS UR S6)及船级社防寒规范、极地船级(POLAR CLASS)规范、俄罗斯船级社(RMRS)规范。文中对三大类规范之间的差异进行了对比分析,包括适用范围、设计温度和钢级选取等,提出有价值的结论和建议,以期为极地低温环境下船体结构选材设计提供参考。
