Since the discovery in 2011,MXenes have become the rising star in the field of two-dimensional materials.Benefiting from the metallic-level conductivity,large and adjustable gallery spacing,low ion diffusion barrier,r...Since the discovery in 2011,MXenes have become the rising star in the field of two-dimensional materials.Benefiting from the metallic-level conductivity,large and adjustable gallery spacing,low ion diffusion barrier,rich surface chemistry,superior mechanical strength,MXenes exhibit great application prospects in energy storage and conversion,sensors,optoelectronics,electromagnetic interference shielding and biomedicine.Nevertheless,two issues seriously deteriorate the further development of MXenes.One is the high experimental risk of common preparation methods such as HF etching,and the other is the difficulty in obtaining MXenes with controllable surface groups.Recently,Lewis acidic etching,as a brand-new preparation strategy for MXenes,has attracted intensive attention due to its high safety and the ability to endow MXenes with uniform terminations.However,a comprehensive review of Lewis acidic etching method has not been reported yet.Herein,we first introduce the Lewis acidic etching from the following four aspects:etching mechanism,terminations regulation,in-situ formed metals and delamination of multi-layered MXenes.Further,the applications of MXenes and MXene-based hybrids obtained by Lewis acidic etching route in energy storage and conversion,sensors and microwave absorption are carefully summarized.Finally,some challenges and opportunities of Lewis acidic etching strategy are also presented.展开更多
According to the requirements of the bus terminal regulator,a linear regulator with 3-A source-sink current ability is presented.The use of the NMOS pass transistor and load current feedback technique enhances the sys...According to the requirements of the bus terminal regulator,a linear regulator with 3-A source-sink current ability is presented.The use of the NMOS pass transistor and load current feedback technique enhances the system current ability and response speed.The method of adaptive zero compensation realizes loop stability over the whole load range for either source or sink loop.Furthermore,the transconductance matching technique reduces the shoot-through current through the output stage to less than 3μA.The regulator has been fabricated with a 0.6-μm 30 V BCD process successfully,and the area size is about 1 mm;.With a 20μF output capacitor, the maximum transient output-voltage variation is within 3.5%of the output voltage with load step changes of±2 A/lμs.At the load range of±3 A,the variation of output voltage is less than±15 mV.展开更多
基金supported by the Highstar Corporation HSD20210118Taihu Electric Corporation 0001。
文摘Since the discovery in 2011,MXenes have become the rising star in the field of two-dimensional materials.Benefiting from the metallic-level conductivity,large and adjustable gallery spacing,low ion diffusion barrier,rich surface chemistry,superior mechanical strength,MXenes exhibit great application prospects in energy storage and conversion,sensors,optoelectronics,electromagnetic interference shielding and biomedicine.Nevertheless,two issues seriously deteriorate the further development of MXenes.One is the high experimental risk of common preparation methods such as HF etching,and the other is the difficulty in obtaining MXenes with controllable surface groups.Recently,Lewis acidic etching,as a brand-new preparation strategy for MXenes,has attracted intensive attention due to its high safety and the ability to endow MXenes with uniform terminations.However,a comprehensive review of Lewis acidic etching method has not been reported yet.Herein,we first introduce the Lewis acidic etching from the following four aspects:etching mechanism,terminations regulation,in-situ formed metals and delamination of multi-layered MXenes.Further,the applications of MXenes and MXene-based hybrids obtained by Lewis acidic etching route in energy storage and conversion,sensors and microwave absorption are carefully summarized.Finally,some challenges and opportunities of Lewis acidic etching strategy are also presented.
基金supported by the National Natural Science Foundation of China(Nos.60806043,60806009)the Special Fund for Basic Scientific Research of Central Colleges Chang'an University,China(No.CHD2010JC077)the Key Laboratory Foundation of Shaanxi Engineering and Technique Research Center for Road and Traffic Detection,China
文摘According to the requirements of the bus terminal regulator,a linear regulator with 3-A source-sink current ability is presented.The use of the NMOS pass transistor and load current feedback technique enhances the system current ability and response speed.The method of adaptive zero compensation realizes loop stability over the whole load range for either source or sink loop.Furthermore,the transconductance matching technique reduces the shoot-through current through the output stage to less than 3μA.The regulator has been fabricated with a 0.6-μm 30 V BCD process successfully,and the area size is about 1 mm;.With a 20μF output capacitor, the maximum transient output-voltage variation is within 3.5%of the output voltage with load step changes of±2 A/lμs.At the load range of±3 A,the variation of output voltage is less than±15 mV.
