Multichip on Ahnnintnn Metal Plate（MOAMP） technology with simple structure and low thermal resistance is developed for effective heat reratrval of Light Emitting Diode（LED） p-n junction and LED lighting module to ...Multichip on Ahnnintnn Metal Plate（MOAMP） technology with simple structure and low thermal resistance is developed for effective heat reratrval of Light Emitting Diode（LED） p-n junction and LED lighting module to have high reliability. The thermal resistance of LED modules was numerical and experimental. Thermal resistance from the jtnction to aluminten metal plate, considering input power of IFD module using MOAMP technology, is 3.02 K/W, 3.23 K/W for the measured and calculated, respectively. We expect that the reported MOAMP technology with low thermal resistance will be a promising solution for high power LED fighting modules.展开更多
Current understanding of phonons treats them as plane waves/quasi-particles of atomic vibration that propagate and scatter.The problem is that conceptually,when any level of disorder is introduced,whether compositiona...Current understanding of phonons treats them as plane waves/quasi-particles of atomic vibration that propagate and scatter.The problem is that conceptually,when any level of disorder is introduced,whether compositional or structural,the character of vibrational modes in solids changes,yet nearly all theoretical treatments continue to assume phonons are still waves.For example,the phonon contributions to alloy thermal conductivity(TC)rely on this assumption and are most often computed from the virtual crystal approximation(VCA).Good agreement is obtained in some cases,but there are many instances where it fails—both quantitatively and qualitatively.Here,we show that the conventional theory and understanding of phonons requires revision,because the critical assumption that all phonons/normal modes resemble plane waves with well-defined velocities is no longer valid when disorder is introduced.Here we show,surprisingly,that the character of phonons changes dramatically within the first few percent of impurity concentration,beyond which phonons more closely resemble the modes found in amorphous materials.We then utilize a different theory that can treat modes with any character and experimentally confirm its new insights.展开更多
文摘Multichip on Ahnnintnn Metal Plate（MOAMP） technology with simple structure and low thermal resistance is developed for effective heat reratrval of Light Emitting Diode（LED） p-n junction and LED lighting module to have high reliability. The thermal resistance of LED modules was numerical and experimental. Thermal resistance from the jtnction to aluminten metal plate, considering input power of IFD module using MOAMP technology, is 3.02 K/W, 3.23 K/W for the measured and calculated, respectively. We expect that the reported MOAMP technology with low thermal resistance will be a promising solution for high power LED fighting modules.
基金support from the National Science Foundation through a Career Award(1554050)for A.Henry.
文摘Current understanding of phonons treats them as plane waves/quasi-particles of atomic vibration that propagate and scatter.The problem is that conceptually,when any level of disorder is introduced,whether compositional or structural,the character of vibrational modes in solids changes,yet nearly all theoretical treatments continue to assume phonons are still waves.For example,the phonon contributions to alloy thermal conductivity(TC)rely on this assumption and are most often computed from the virtual crystal approximation(VCA).Good agreement is obtained in some cases,but there are many instances where it fails—both quantitatively and qualitatively.Here,we show that the conventional theory and understanding of phonons requires revision,because the critical assumption that all phonons/normal modes resemble plane waves with well-defined velocities is no longer valid when disorder is introduced.Here we show,surprisingly,that the character of phonons changes dramatically within the first few percent of impurity concentration,beyond which phonons more closely resemble the modes found in amorphous materials.We then utilize a different theory that can treat modes with any character and experimentally confirm its new insights.
