Abstract modern social awareness and people＇ s aesthetic psychology has undergone tremendous changes in the design of modem ceramic art poses severe requirements. This article from the perspective of modem lifestyles...Abstract modern social awareness and people＇ s aesthetic psychology has undergone tremendous changes in the design of modem ceramic art poses severe requirements. This article from the perspective of modem lifestyles, made from ceramic design concepts, modeling, implication, decoration, materials and technology and other aspects of transformation and innovation, in order to achieve adapt to the modem lifestyle, aesthetic purposes.展开更多
Aprototype of YAG： Ce （Y3Al5O12） luminous bulk ceramic as a remote phosphor for white LED illumination was fabricated in air through a strategy of silica addition. With increasing the amount of silica in a specific...Aprototype of YAG： Ce （Y3Al5O12） luminous bulk ceramic as a remote phosphor for white LED illumination was fabricated in air through a strategy of silica addition. With increasing the amount of silica in a specific range, the opaque sample turns to be semi-transparent. The precipitation of crystals is verified to be in pure YAG phase by X-ray diffraction （XRD）. Beyond the limit of silica amount, the dominant phase of YAG crystal is found to coexist with a small amount of newly-formed Y2Si2O7, Al2O3 and the amorphous phase. The YAG crystals are with a grain size of approximately 2 μm and distribute evenly. The YAG hosts after structural modification via addition of silica result in yellow band emission of 5d → 4f transition peaked around 535 nm as excited by a blue LED, owing to the self-reduction of Ce^4＋ to Ce^3＋ even in the absence ofreductive atmosphere.展开更多
It is well known that interactions between the leading edge of a blade and incoming vortical structures produce a sharp rise in fluctuating pressure nearby,contributing significantly to the noise production in various...It is well known that interactions between the leading edge of a blade and incoming vortical structures produce a sharp rise in fluctuating pressure nearby,contributing significantly to the noise production in various types of rotorcrafts.To suppress this fluctuating pressure and subsequently induced noise,as the first step,active control of interactions between an airfoil and incoming cylinder-generated vortices,which mimics the practical phenomenon,was experimentally investigated.The essence of the control is to create a local perturbation,using piezo-ceramic actuators,on the surface near the leading edge of the airfoil,thus modifying the airfoil-vortex interactions.Both open-and closed-loop methods were used,where the surface perturbation was controlled by an external sinusoidal wave and a feedback pressure signal from a pressure transducer installed at the leading edge,respectively.It was observed that the closed-loop control was superior to the open-loop one;the closed-and open-loop controls achieve a maximum reduction in the pressure fluctuation at the dominant vortex frequency by 32% and 11%,respectively.The detailed physics behind the observations was discussed.展开更多
文摘Abstract modern social awareness and people＇ s aesthetic psychology has undergone tremendous changes in the design of modem ceramic art poses severe requirements. This article from the perspective of modem lifestyles, made from ceramic design concepts, modeling, implication, decoration, materials and technology and other aspects of transformation and innovation, in order to achieve adapt to the modem lifestyle, aesthetic purposes.
基金supported by the National Natural Science Foundation of China (Nos.50872091, 50802062, and 21076161)the Key Discipline for Materials Physics and Chemistry of Tianjin in China (Nos.10SYSYJC28100, 2006ZD30, and 06YFJMJC0230)
文摘Aprototype of YAG： Ce （Y3Al5O12） luminous bulk ceramic as a remote phosphor for white LED illumination was fabricated in air through a strategy of silica addition. With increasing the amount of silica in a specific range, the opaque sample turns to be semi-transparent. The precipitation of crystals is verified to be in pure YAG phase by X-ray diffraction （XRD）. Beyond the limit of silica amount, the dominant phase of YAG crystal is found to coexist with a small amount of newly-formed Y2Si2O7, Al2O3 and the amorphous phase. The YAG crystals are with a grain size of approximately 2 μm and distribute evenly. The YAG hosts after structural modification via addition of silica result in yellow band emission of 5d → 4f transition peaked around 535 nm as excited by a blue LED, owing to the self-reduction of Ce^4＋ to Ce^3＋ even in the absence ofreductive atmosphere.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51076153, 50836006) and‘Hundred Talent Program’ of Chinese Academy of Sciences
文摘It is well known that interactions between the leading edge of a blade and incoming vortical structures produce a sharp rise in fluctuating pressure nearby,contributing significantly to the noise production in various types of rotorcrafts.To suppress this fluctuating pressure and subsequently induced noise,as the first step,active control of interactions between an airfoil and incoming cylinder-generated vortices,which mimics the practical phenomenon,was experimentally investigated.The essence of the control is to create a local perturbation,using piezo-ceramic actuators,on the surface near the leading edge of the airfoil,thus modifying the airfoil-vortex interactions.Both open-and closed-loop methods were used,where the surface perturbation was controlled by an external sinusoidal wave and a feedback pressure signal from a pressure transducer installed at the leading edge,respectively.It was observed that the closed-loop control was superior to the open-loop one;the closed-and open-loop controls achieve a maximum reduction in the pressure fluctuation at the dominant vortex frequency by 32% and 11%,respectively.The detailed physics behind the observations was discussed.
