A high performance VHF power VDMOSFET,ap plying to the mobile communications,is developed,which can deliver an output power of 12W with the drain efficiency of 70% as well as the gain of 12dB at a low supply voltag...A high performance VHF power VDMOSFET,ap plying to the mobile communications,is developed,which can deliver an output power of 12W with the drain efficiency of 70% as well as the gain of 12dB at a low supply voltage of 12V and 175MHz.It is fabricated by using the terraced gat e structure and refractory molybdenum (Mo) gate technology.展开更多
A fully integrated class-E power amplifier（PA） at 2.4 GHz implemented in a 0. 18 μm 6-metal-layer mixed/RF CMOS （ complementary metal-oxide-semiconductor transistor ） technology is presented. A two-stage amplific...A fully integrated class-E power amplifier（PA） at 2.4 GHz implemented in a 0. 18 μm 6-metal-layer mixed/RF CMOS （ complementary metal-oxide-semiconductor transistor ） technology is presented. A two-stage amplification structure is chosen for this PA. The driving stage produces a high swing switch signal by using resonation technology. The output stage is designed as a class-E topology to realize the power amplification. Under a 1.2 V power supply, the PA delivers a maximum output power of 8. 8 dBm with a power-added efficiency （PAE） of 44%. A new power control method for the class-E power amplifier is described. By changing the amplitude and duty cycle of the signal which enters the class-E switch transistor, the output power can be covered from - 3 to 8. 8 dBm through a three-bit control word. The proposed PA can be used in low power applications, such as wireless sensor networks and biotelemetry systems.展开更多
Based on analyzing the moving principle of media in ball mill, it is implicated that there is the significant difference of movement situation among each single layer. A new method to calculate each single was put for...Based on analyzing the moving principle of media in ball mill, it is implicated that there is the significant difference of movement situation among each single layer. A new method to calculate each single was put forward. The results from lab experiment and actual data from 26 sets industrial mills state indicate that the new calculation method reaches the high accuracy with excellent practicability.展开更多
The hot working mechanism of 2Cr11 MolVNbN steel was investigated by means of compression tests at temperatures of900-1150 ℃ and strain rates of 0.005-5 s^(-1).At strains of 0.2,0.3,0.5 and 0.7,the relationship among...The hot working mechanism of 2Cr11 MolVNbN steel was investigated by means of compression tests at temperatures of900-1150 ℃ and strain rates of 0.005-5 s^(-1).At strains of 0.2,0.3,0.5 and 0.7,the relationship among strain rate sensitivity,power dissipation efficiency and instability parameter under different conditions were studied.Power dissipation maps and instability maps at different strains were established.The optimal and the instable deformation regimes were established by the processing maps based on the dynamic material model.The processing maps were developed for the typical strains of 0.2,0.3,0.5 and 0.7,predicting the instability regions occurring at high strain rate more than 0.05 s^(-1),which should be avoided during hot deformation.The optimized processing parameters for hot working of 2CrllMolVNbN supercritical stainless steel were temperatures of 1080-1120 ℃ and strain rates of 0.005-0.01 s^(-1).展开更多
The impact of ultrasonic power density on changes of heavy metals during sludge sonication was inves-tigated. Results showed that ultrasound could release heavy metals from sludge into the supernatant. There existed a...The impact of ultrasonic power density on changes of heavy metals during sludge sonication was inves-tigated. Results showed that ultrasound could release heavy metals from sludge into the supernatant. There existed an effective power density range of 0.8-1.6 W·ml?1 for the release of the total heavy metal; there was little release below 0.8 W·ml?1 and too high power density was adverse to the release. Furthermore, sonication showed selective release of heavy metal from sludge to the supernatant; copper, cadmium and lead were not released by sonication, while arsenic and nickel were released easily and their release ratio could reach 40%. The effective energy range for each heavy metal was also different that 0.8-1.2 W·ml?1 for arsenic, 0.5-1.6 W·ml?1 for nickel, and 0.8-1.6 W·ml?1 for mercury and chrome. The differences among heavy metal release during sonication might be explained by the different distribution of chemical fractions of each metal in sludge. Such selectivity could be used to control heavy metal release during sludge treatment.展开更多
This paper presents an up-conversion mixer for 2.4GHz wireless sensor networks in 0. 181xm RF complementary metal-oxide semiconductor （CMOS） technology. It is based on a double-balanced Gilbert cell type. With two G...This paper presents an up-conversion mixer for 2.4GHz wireless sensor networks in 0. 181xm RF complementary metal-oxide semiconductor （CMOS） technology. It is based on a double-balanced Gilbert cell type. With two Gilbert cells it was applied quadrature modulation. Operational ampli- tiers are used in this design to improve the conversion gain under low power consumption. The mixer design is based on 0.18txm RF CMOS process. And the mixer test results indicate that under 1.8V power supply, with input frequency 2.4 - 2.4835GHz, the conversion voltage gain is 1.2 - 2dB. When the output frequency is 2.4GHz, its power gain is -4.46dB, and its input referred 1 dB com- pression point is -11.5dBm and it consumes 1.77mA current.展开更多
A two-stage power amplifier operated at 925 MHz was designed and fabricated in Jazz' s 0.35μmSiGe BiCMOS process.It was fully integrated excluding the inductors and the output matching network.Under a single 3.3V...A two-stage power amplifier operated at 925 MHz was designed and fabricated in Jazz' s 0.35μmSiGe BiCMOS process.It was fully integrated excluding the inductors and the output matching network.Under a single 3.3V supply voltage,the off-chip bonding test results indicated that the circuit has a smallsignal gain of more than 24dB,the input and output reflectance are less than- 24dB and-10dB,re-spectively,and the maximal output power is 23.5 dBm.At output power of 23.1 dBm,the PAE(poweradded efficiency)is 30.2%,the IMD2 and IMD3 are less than- 32 dBc and-46 dBc,respectively.The chip size is 1.27mm ×0.9mm.展开更多
This paper deals with optimization of hard switching commutation mode for high-power, high-frequency consumer applications for selected power transistor. The experimental investigation of suitable settings is outgoing...This paper deals with optimization of hard switching commutation mode for high-power, high-frequency consumer applications for selected power transistor. The experimental investigation of suitable settings is outgoing from simulation analysis of hard switching for different transistor structures. For these purposes, the simulation models of power semiconductor switches with high level of validity have been used. After that, the experimental analysis for selected transistor was done with change of parameters that are influencing commutation process of transistor. Target of such kind of analysis was to reach as low switching losses as possible, achieving high power density and efficiency of power system, without utilization of improved switching techniques such as resonant switching. The results confirm that this task is realizable through use of progressive semiconductor devices such as SiC diodes and/or through latest families of MOSFET devices.展开更多
文摘A high performance VHF power VDMOSFET,ap plying to the mobile communications,is developed,which can deliver an output power of 12W with the drain efficiency of 70% as well as the gain of 12dB at a low supply voltage of 12V and 175MHz.It is fabricated by using the terraced gat e structure and refractory molybdenum (Mo) gate technology.
基金The National High Technology Research and Development Program of China(863 Program)(No.2007AA01Z2A7)
文摘A fully integrated class-E power amplifier（PA） at 2.4 GHz implemented in a 0. 18 μm 6-metal-layer mixed/RF CMOS （ complementary metal-oxide-semiconductor transistor ） technology is presented. A two-stage amplification structure is chosen for this PA. The driving stage produces a high swing switch signal by using resonation technology. The output stage is designed as a class-E topology to realize the power amplification. Under a 1.2 V power supply, the PA delivers a maximum output power of 8. 8 dBm with a power-added efficiency （PAE） of 44%. A new power control method for the class-E power amplifier is described. By changing the amplitude and duty cycle of the signal which enters the class-E switch transistor, the output power can be covered from - 3 to 8. 8 dBm through a three-bit control word. The proposed PA can be used in low power applications, such as wireless sensor networks and biotelemetry systems.
文摘Based on analyzing the moving principle of media in ball mill, it is implicated that there is the significant difference of movement situation among each single layer. A new method to calculate each single was put forward. The results from lab experiment and actual data from 26 sets industrial mills state indicate that the new calculation method reaches the high accuracy with excellent practicability.
基金Project(CDJZR14130006)supported by the Fundamental Research Funds for the Central Universities,China
文摘The hot working mechanism of 2Cr11 MolVNbN steel was investigated by means of compression tests at temperatures of900-1150 ℃ and strain rates of 0.005-5 s^(-1).At strains of 0.2,0.3,0.5 and 0.7,the relationship among strain rate sensitivity,power dissipation efficiency and instability parameter under different conditions were studied.Power dissipation maps and instability maps at different strains were established.The optimal and the instable deformation regimes were established by the processing maps based on the dynamic material model.The processing maps were developed for the typical strains of 0.2,0.3,0.5 and 0.7,predicting the instability regions occurring at high strain rate more than 0.05 s^(-1),which should be avoided during hot deformation.The optimized processing parameters for hot working of 2CrllMolVNbN supercritical stainless steel were temperatures of 1080-1120 ℃ and strain rates of 0.005-0.01 s^(-1).
基金Supported by the Basic Research Funds in Renmin University of China from the center government(12XNL101)
文摘The impact of ultrasonic power density on changes of heavy metals during sludge sonication was inves-tigated. Results showed that ultrasound could release heavy metals from sludge into the supernatant. There existed an effective power density range of 0.8-1.6 W·ml?1 for the release of the total heavy metal; there was little release below 0.8 W·ml?1 and too high power density was adverse to the release. Furthermore, sonication showed selective release of heavy metal from sludge to the supernatant; copper, cadmium and lead were not released by sonication, while arsenic and nickel were released easily and their release ratio could reach 40%. The effective energy range for each heavy metal was also different that 0.8-1.2 W·ml?1 for arsenic, 0.5-1.6 W·ml?1 for nickel, and 0.8-1.6 W·ml?1 for mercury and chrome. The differences among heavy metal release during sonication might be explained by the different distribution of chemical fractions of each metal in sludge. Such selectivity could be used to control heavy metal release during sludge treatment.
基金Supported by the National High Technology Research and Development Program(No.2007AA01Z2A7)the Special Fund of Jiangsu Province for the Transformation of Scientific and Technological Achievements(No.BA2010073)
文摘This paper presents an up-conversion mixer for 2.4GHz wireless sensor networks in 0. 181xm RF complementary metal-oxide semiconductor （CMOS） technology. It is based on a double-balanced Gilbert cell type. With two Gilbert cells it was applied quadrature modulation. Operational ampli- tiers are used in this design to improve the conversion gain under low power consumption. The mixer design is based on 0.18txm RF CMOS process. And the mixer test results indicate that under 1.8V power supply, with input frequency 2.4 - 2.4835GHz, the conversion voltage gain is 1.2 - 2dB. When the output frequency is 2.4GHz, its power gain is -4.46dB, and its input referred 1 dB com- pression point is -11.5dBm and it consumes 1.77mA current.
基金Supported by the High Technology Research and Development Programme of China (2006AA03Z418)
文摘A two-stage power amplifier operated at 925 MHz was designed and fabricated in Jazz' s 0.35μmSiGe BiCMOS process.It was fully integrated excluding the inductors and the output matching network.Under a single 3.3V supply voltage,the off-chip bonding test results indicated that the circuit has a smallsignal gain of more than 24dB,the input and output reflectance are less than- 24dB and-10dB,re-spectively,and the maximal output power is 23.5 dBm.At output power of 23.1 dBm,the PAE(poweradded efficiency)is 30.2%,the IMD2 and IMD3 are less than- 32 dBc and-46 dBc,respectively.The chip size is 1.27mm ×0.9mm.
文摘This paper deals with optimization of hard switching commutation mode for high-power, high-frequency consumer applications for selected power transistor. The experimental investigation of suitable settings is outgoing from simulation analysis of hard switching for different transistor structures. For these purposes, the simulation models of power semiconductor switches with high level of validity have been used. After that, the experimental analysis for selected transistor was done with change of parameters that are influencing commutation process of transistor. Target of such kind of analysis was to reach as low switching losses as possible, achieving high power density and efficiency of power system, without utilization of improved switching techniques such as resonant switching. The results confirm that this task is realizable through use of progressive semiconductor devices such as SiC diodes and/or through latest families of MOSFET devices.
