在航天遥感领域,波长在10μm以上的长波探测器仍以Hg Cd Te光导型探测器为主,在红外探测成像方面发挥着重要作用。非均匀性是目前长波光导探测器突出的问题之一,设计了一种数模混合的非均匀性校正的长波光导探测器读出电路。该电路不仅...在航天遥感领域,波长在10μm以上的长波探测器仍以Hg Cd Te光导型探测器为主,在红外探测成像方面发挥着重要作用。非均匀性是目前长波光导探测器突出的问题之一,设计了一种数模混合的非均匀性校正的长波光导探测器读出电路。该电路不仅可以有效地解决线列长波光导探测器电阻非均匀性问题,还可以增大ROIC输出信号的动态范围,几乎不增加读出电路功耗。经过仿真测试表明:非均匀性问题有了明显的改善,能够使其非均匀性降为0.5%以内,在常温和低温下都能正常工作。该校正电路不仅能解决当前工程中的关键问题,还对今后高性能大面阵长波光导探测器读出电路的设计具有重要的指导意义。展开更多
A two-dimensional model for freezing and thawing phase change heat transfer in biological tissue embedded with two cryoprobes was established.In this model,the blood vessels were considered as tree-like branched fract...A two-dimensional model for freezing and thawing phase change heat transfer in biological tissue embedded with two cryoprobes was established.In this model,the blood vessels were considered as tree-like branched fractal network,and the effective flow rate and effective thermal conductivity of blood were obtained by fractal method.The temperature distribution and ice crystal growth process in biological tissue embedded with two cryoprobes during freezing-thawing process were numerically simulated.The results show that the growth velocity of ice crystal in freezing process from 200 to 400 s is more rapid than that from 400 to 600 s. Thawing process of frozen tissue occurs in the regions around cryoprobes tips and tissue boundary simultaneously,and the phase interfaces are close to each other until ice crystal melts completely.The distance of two cryoprobes has a more profound effect on the temperature distribution in freezing process at 400 s than at 800 s.展开更多
文摘在航天遥感领域,波长在10μm以上的长波探测器仍以Hg Cd Te光导型探测器为主,在红外探测成像方面发挥着重要作用。非均匀性是目前长波光导探测器突出的问题之一,设计了一种数模混合的非均匀性校正的长波光导探测器读出电路。该电路不仅可以有效地解决线列长波光导探测器电阻非均匀性问题,还可以增大ROIC输出信号的动态范围,几乎不增加读出电路功耗。经过仿真测试表明:非均匀性问题有了明显的改善,能够使其非均匀性降为0.5%以内,在常温和低温下都能正常工作。该校正电路不仅能解决当前工程中的关键问题,还对今后高性能大面阵长波光导探测器读出电路的设计具有重要的指导意义。
基金Project(50436030)supported by the National Natural Science Foundation of China
文摘A two-dimensional model for freezing and thawing phase change heat transfer in biological tissue embedded with two cryoprobes was established.In this model,the blood vessels were considered as tree-like branched fractal network,and the effective flow rate and effective thermal conductivity of blood were obtained by fractal method.The temperature distribution and ice crystal growth process in biological tissue embedded with two cryoprobes during freezing-thawing process were numerically simulated.The results show that the growth velocity of ice crystal in freezing process from 200 to 400 s is more rapid than that from 400 to 600 s. Thawing process of frozen tissue occurs in the regions around cryoprobes tips and tissue boundary simultaneously,and the phase interfaces are close to each other until ice crystal melts completely.The distance of two cryoprobes has a more profound effect on the temperature distribution in freezing process at 400 s than at 800 s.
