Conventional multilevel inverters often suffer from high harmonic distortion and increased design complexity due to the need for numerous power semiconductor components,particularly at elevated voltage levels.Addressi...Conventional multilevel inverters often suffer from high harmonic distortion and increased design complexity due to the need for numerous power semiconductor components,particularly at elevated voltage levels.Addressing these shortcomings,thiswork presents a robust 15-level PackedUCell(PUC)inverter topology designed for renewable energy and grid-connected applications.The proposed systemintegrates a sensor less proportional-resonant(PR)controller with an advanced carrier-based pulse width modulation scheme.This approach efficiently balances capacitor voltage,minimizes steady-state error,and strongly suppresses both zero and third-order harmonics resulting in reduced total harmonic distortion and enhanced voltage regulation.Additionally,a novel switching algorithm simplifies the design and implementation,further lowering voltage stress across switches.Extensive simulation results validate the performance under various resistive and resistive-inductive load conditions,demonstrating compliance with IEEE-519 THD standards and robust operation under dynamic changes.The proposed sensorless PR-controlled 15-PUC inverter thus offers a compelling,cost-effective solution for efficient power conversion in next-generation renewable energy systems.展开更多
Two T vectors were generated by restriction endonuclease Xcm Ⅰ instead of Taq or other DNA polymerases to create the 3’T over hangs.A fragment of adenoviral genome position 10659-11865 was amplified by PCR and Xcm ...Two T vectors were generated by restriction endonuclease Xcm Ⅰ instead of Taq or other DNA polymerases to create the 3’T over hangs.A fragment of adenoviral genome position 10659-11865 was amplified by PCR and Xcm Ⅰ recognition sites were introduced to both ends of the PCR product.This fragment was cloned into the Sma Ⅰ site of pUC18 or the linearized pUC18 with its polylinker deleted.The recombinant plamids were cleaved with Xcm Ⅰ.the larger fragments generated which had 3’T over hangs at both ends were used as T vctors.Genes of rotavirus VP7 and the plasminogen k5 were successfully cloned into these two T vectors with recombination efficiency (recombinants/transformants×100%) of 100%,no blue/white clolny screening assay was needed.展开更多
应用原子力显微镜(atomic force microscope)对在云母表面铺展干燥的限制性内切酶(EcoR I)作用前后的pUC18质粒DNA分子进行扫描。扫描结果显示,质量浓度为1μg/mLpUC18质粒DNA分子在呈现典型的闭环环状结构,局部可见颗粒状或粗线型聚合...应用原子力显微镜(atomic force microscope)对在云母表面铺展干燥的限制性内切酶(EcoR I)作用前后的pUC18质粒DNA分子进行扫描。扫描结果显示,质量浓度为1μg/mLpUC18质粒DNA分子在呈现典型的闭环环状结构,局部可见颗粒状或粗线型聚合DNA片断。内切酶作用后,呈现网络状分布的细线状DNA分子。通过原子力显微镜对酶作用前后的质粒DNA分子的结构表征,对阐述酶切过程中DNA分子的结构变化机制打下基础。展开更多
文摘Conventional multilevel inverters often suffer from high harmonic distortion and increased design complexity due to the need for numerous power semiconductor components,particularly at elevated voltage levels.Addressing these shortcomings,thiswork presents a robust 15-level PackedUCell(PUC)inverter topology designed for renewable energy and grid-connected applications.The proposed systemintegrates a sensor less proportional-resonant(PR)controller with an advanced carrier-based pulse width modulation scheme.This approach efficiently balances capacitor voltage,minimizes steady-state error,and strongly suppresses both zero and third-order harmonics resulting in reduced total harmonic distortion and enhanced voltage regulation.Additionally,a novel switching algorithm simplifies the design and implementation,further lowering voltage stress across switches.Extensive simulation results validate the performance under various resistive and resistive-inductive load conditions,demonstrating compliance with IEEE-519 THD standards and robust operation under dynamic changes.The proposed sensorless PR-controlled 15-PUC inverter thus offers a compelling,cost-effective solution for efficient power conversion in next-generation renewable energy systems.
文摘Two T vectors were generated by restriction endonuclease Xcm Ⅰ instead of Taq or other DNA polymerases to create the 3’T over hangs.A fragment of adenoviral genome position 10659-11865 was amplified by PCR and Xcm Ⅰ recognition sites were introduced to both ends of the PCR product.This fragment was cloned into the Sma Ⅰ site of pUC18 or the linearized pUC18 with its polylinker deleted.The recombinant plamids were cleaved with Xcm Ⅰ.the larger fragments generated which had 3’T over hangs at both ends were used as T vctors.Genes of rotavirus VP7 and the plasminogen k5 were successfully cloned into these two T vectors with recombination efficiency (recombinants/transformants×100%) of 100%,no blue/white clolny screening assay was needed.
文摘应用原子力显微镜(atomic force microscope)对在云母表面铺展干燥的限制性内切酶(EcoR I)作用前后的pUC18质粒DNA分子进行扫描。扫描结果显示,质量浓度为1μg/mLpUC18质粒DNA分子在呈现典型的闭环环状结构,局部可见颗粒状或粗线型聚合DNA片断。内切酶作用后,呈现网络状分布的细线状DNA分子。通过原子力显微镜对酶作用前后的质粒DNA分子的结构表征,对阐述酶切过程中DNA分子的结构变化机制打下基础。
