In this paper, we first introduce the concept ＂harmonically convex functions＂ in the second sense and establish several Hermite-Hadamard type inequalities for harmonically convex functions in the second sense. Final...In this paper, we first introduce the concept ＂harmonically convex functions＂ in the second sense and establish several Hermite-Hadamard type inequalities for harmonically convex functions in the second sense. Finally, some applications to special mean are shown.展开更多
In this work, a mathematical model of an elastic material with cylindrical cavity will be constructed. The governing equations will be taken into the context of the fractional order generalized thermoelasticity theory...In this work, a mathematical model of an elastic material with cylindrical cavity will be constructed. The governing equations will be taken into the context of the fractional order generalized thermoelasticity theory (Youssef 2010). Laplace transform and direct approach will be used to obtain the solution when the boundary of the cavity is exposed to harmonically heat with constant angular frequency of thermal vibration. The inverse of Laplace transforms will be computed numerically using a method based on Fourier expansion techniques. Some comparisons have been shown in figures to present the effect of the fractional order parameter and the angular frequency of thermal vibration on all the studied felids.展开更多
We investigate two different kinds of resonant current regulators for a doubly fed induction generator(DFIG) under distorted grid voltage conditions: proportional integral resonant(PIR) regulator with traditional reso...We investigate two different kinds of resonant current regulators for a doubly fed induction generator(DFIG) under distorted grid voltage conditions: proportional integral resonant(PIR) regulator with traditional resonant part and vector proportional integral(VPI) regulator with VPI resonant part. Based on the mathematical model of DFIG under distorted grid voltage, the transfer function and frequency response characteristics of the two current regulators are analyzed and compared. The superiority of the VPI current regulator over the PIR regulator is pointed out, and the influence of discretization methods on the performance of the resonant current regulator is studied. All the results are validated by MATLAB simulation and experiments.展开更多
We report the generation of passively tunable high peak signal-to-noise ratio harmonic mode-locked （HML） all- normal-dispersion Yb-doped fiber laser with a single birefringent filter in a ring cavity configuration. ...We report the generation of passively tunable high peak signal-to-noise ratio harmonic mode-locked （HML） all- normal-dispersion Yb-doped fiber laser with a single birefringent filter in a ring cavity configuration. The highest fourth harmonic of the fundamental mode-locked frequency at a repetition rate of 88 MHz is obtained. The pulses are compressed to 627fs by using an external grating-pair compressor. For the fourth HML output, the peak signal-to-noise ratio of the rf is 73dB and the average power is as high as 110mW with the pump power of 500mW. Soliton bunches which contain multipulses are also observed in the weak mode-locked regime of the HML, and the separation between interpulses in a dissipative soliton bunch can be controlled by adjustment of the waveplates and spectral filter in the cavity：展开更多
A Ka-band sub-harmonically pumped resistive mixer （SHPRM） was designed and fabricated using the standard 0.18-μm complementary metal-oxide-semiconductor （CMOS） technology. An area-effective asymmetric broadside c...A Ka-band sub-harmonically pumped resistive mixer （SHPRM） was designed and fabricated using the standard 0.18-μm complementary metal-oxide-semiconductor （CMOS） technology. An area-effective asymmetric broadside coupled spiral Marchand balance-to-unbalance （balun） with magnitude and phase imbalance compensation is used in the mixer to transform local oscillation （LO） signal from single to differential mode. The results showed that the SHPRM achieves the conversion gain of -15- -12.5 dB at fixed fIF=0.5 GHz with 8 dBm LO input power for the radio frequency （RF） bandwidth of 28 35 GHz. The in-band LO-intermediate freqency （IF）, RF-IF, and LO-RF isolations are better than 31, 34, and 36 dB, respectively. Besides, the 2LO-IF and 2LO-RF isolations are better than 60 and 45 dB, respectively. The measured input referred PIdB and 3rd-order inter-modulation intercept point （IIP3） are 0.5 and 10.5 dBm, respectively. The measurement is performed under a gate bias voltage as low as 0.1 V and the whole chip only occupies an area of 0.33 mm^2 including pads.展开更多
基金The Doctoral Programs Foundation(20113401110009)of Education Ministry of ChinaNatural Science Research Project(2012kj11)of Hefei Normal University+1 种基金Universities Natural Science Foundation(KJ2013A220)of Anhui ProvinceResearch Project of Graduates Innovation Fund(2014yjs02)
文摘In this paper, we first introduce the concept ＂harmonically convex functions＂ in the second sense and establish several Hermite-Hadamard type inequalities for harmonically convex functions in the second sense. Finally, some applications to special mean are shown.
文摘In this work, a mathematical model of an elastic material with cylindrical cavity will be constructed. The governing equations will be taken into the context of the fractional order generalized thermoelasticity theory (Youssef 2010). Laplace transform and direct approach will be used to obtain the solution when the boundary of the cavity is exposed to harmonically heat with constant angular frequency of thermal vibration. The inverse of Laplace transforms will be computed numerically using a method based on Fourier expansion techniques. Some comparisons have been shown in figures to present the effect of the fractional order parameter and the angular frequency of thermal vibration on all the studied felids.
基金Project supported by the National High-Tech R&D Program(863)of China(No.2011AA050204)the National Natural Science Foundation of China(No.51277159)
文摘We investigate two different kinds of resonant current regulators for a doubly fed induction generator(DFIG) under distorted grid voltage conditions: proportional integral resonant(PIR) regulator with traditional resonant part and vector proportional integral(VPI) regulator with VPI resonant part. Based on the mathematical model of DFIG under distorted grid voltage, the transfer function and frequency response characteristics of the two current regulators are analyzed and compared. The superiority of the VPI current regulator over the PIR regulator is pointed out, and the influence of discretization methods on the performance of the resonant current regulator is studied. All the results are validated by MATLAB simulation and experiments.
基金Supported by the National Key Technology R&D Program of the Ministry of Science and Technology under Grant No2012BAC23B03the National Key Basic Research Program of China under Grant No 2013CB922401the National Natural Science Foundation of China under Grants No 11474002
文摘We report the generation of passively tunable high peak signal-to-noise ratio harmonic mode-locked （HML） all- normal-dispersion Yb-doped fiber laser with a single birefringent filter in a ring cavity configuration. The highest fourth harmonic of the fundamental mode-locked frequency at a repetition rate of 88 MHz is obtained. The pulses are compressed to 627fs by using an external grating-pair compressor. For the fourth HML output, the peak signal-to-noise ratio of the rf is 73dB and the average power is as high as 110mW with the pump power of 500mW. Soliton bunches which contain multipulses are also observed in the weak mode-locked regime of the HML, and the separation between interpulses in a dissipative soliton bunch can be controlled by adjustment of the waveplates and spectral filter in the cavity：
基金Project supported by the National Basic Research Program (973) of China (No. 2010CB327404)the National High-Tech R&D Program (863) of China (No. 2011AA10305)the National Natural Science Foundation of China (No. 60901012)
文摘A Ka-band sub-harmonically pumped resistive mixer （SHPRM） was designed and fabricated using the standard 0.18-μm complementary metal-oxide-semiconductor （CMOS） technology. An area-effective asymmetric broadside coupled spiral Marchand balance-to-unbalance （balun） with magnitude and phase imbalance compensation is used in the mixer to transform local oscillation （LO） signal from single to differential mode. The results showed that the SHPRM achieves the conversion gain of -15- -12.5 dB at fixed fIF=0.5 GHz with 8 dBm LO input power for the radio frequency （RF） bandwidth of 28 35 GHz. The in-band LO-intermediate freqency （IF）, RF-IF, and LO-RF isolations are better than 31, 34, and 36 dB, respectively. Besides, the 2LO-IF and 2LO-RF isolations are better than 60 and 45 dB, respectively. The measured input referred PIdB and 3rd-order inter-modulation intercept point （IIP3） are 0.5 and 10.5 dBm, respectively. The measurement is performed under a gate bias voltage as low as 0.1 V and the whole chip only occupies an area of 0.33 mm^2 including pads.
