Because of the randomness of wind speed and the nonlinearity of the dynamic equation of variable pitch control, it is difficult to establish an accurate dynamic equation of variable pitch of floating ...fan. In view of this situation, this paper takes the 5 MW floating wind turbine of the NREL (National Renewable Energy Laboratory) as the research object, establishes the dynamic equation under the basic control of FAST, uses the L-M (nonlinear least square method) to identify the dynamic parameters of the system and obtains the dynamic model of the floating fan under variable pitch stability control. Compared with the output of FAST in the same case, the accuracy of the control model is verified; the FAST base pitch control adopts PI control, but the effect of FAST base control is relatively poor. This paper proposes a disturbance-adaptive pitch control method based on fractional PID feedback; the results show that compared with the FAST base pitch control, the control method is more suitable for variable pitch control of a floating wind turbine. The generating power is more stable, the overshoot of generating power is smaller and the fluctuation of wind speed is smaller. Except for surge and heave, the fluctuation of the other four degrees of the freedom of the floating wind turbine platform is reduced, making it more suitable for the variable pitch control of the floating wind turbine.
•Gene expression profiles of crypt and villus early after IR were characterized.•Activated P53, DNA damage, and apoptosis in stem cells/progenitors.•Transit amplifying cells retained Ki67 expression ...with less P53 activation and apoptosis.
Cells respond differently to DNA damaging agents, which may related to cell context and differentiation status. The aim of present study was to observe the cellular and molecular responses of cells in different differentiation status to ionizing irradiation (IR).
Crypt-villus unit of murine small intestine was adopted as a cell differentiation model. DNA damage responses (DDRs) of crypt and villus were observed 1–24h after 12Gy IR using gene expression microarray analysis, immunohistochemical staining, Western blotting and Electrophoretic Mobility Shift Assay.
Microarray analysis revealed that most differentially expressed genes were related to p53 signaling pathway in crypt 4h after IR and in both crypt and villus 24h after IR. In crypt stem cells/progenitor cells, H2AX was phosphorylated and dephosphorylated quickly, Ki67 attenuated, cell apoptosis enhanced, phosphorylated P53 increased and translocated into nuclear with the ability to bind p53-specific sequence. In upper crypt (transit amplifying cells) and crypt-villus junction, cells kept survive and proliferate as indicated by retained Ki67 expression, suppressed p53 activation, and rare apoptosis.
DDRs varied with cell differentiation status and cell function in small intestinal epithelium. P53 signaling pathway could be an important regulatory mechanism of DDRs.
In 2013, bitter rot of grape was observed in Changbei Vineyard located in Nanchang City, Jiangxi Province, China. Greeneria species was consistently isolated from the diseased grape berries (Vitis ...labruscana cv. Kyoho) at approximately 91% of isolation rate in three independent experiments. The species was identified as Greeneria uvicola based on the morphological characteristics, cultural appearance and sequence analysis. Koch's postulates were fulfilled through pathogenicity tests on detached healthy Kyoho grape berries. To our knowledge, this is the first report of G. uvicola causing bitter rot of grape in China.
A new blight disease on fruit stems of kiwifruit was observed in Fengxin County, Jiangxi Province, China in 2011 and 2012. Twenty isolates from diseased fruit stems were obtained and their ...pathogenicity was confirmed. The pathogen was identified as Glomerella septospora based on morphological characters and molecular methods. This is the first report of fruit stem blight disease of kiwifruit caused by G. septospora.
The use of electrolytic-manganese residue (EMR) as partial cement replacement is a high value-added utilization way, but high-content gypsum in EMR restricts this utilization. This study reports a ...new desulphurized EMR (D-EMR), which aims to remove this barrier. The engineering performances, environmental safety, and economic efficiency were thoroughly evaluated. Particularly, novel thermodynamic modelling, combined with progressive leaching, was developed to reveal the leaching behaviors of heavy metals. The results show that D-EMR presents a low hydraulicity and slight pozzolanic activity. At a 10% replacement level, the composite sample obtains comparable microstructure and macro-properties to the plain cement sample and causes no leaching and radiological hazards. At higher replacement levels, the composite pastes do not pose leaching risks either, provided their inner pH is above 7.5 due to the buffering capacity of hydrates (pH: above 8) and D-EMR (pH: 7.5–8). In addition, from the environmental perspective, desulphurization is economically acceptable.
In this paper, a single-channel two-step voltage-time hybrid domain analog-to-digital converter (ADC) is proposed. To achieve high sampling rate and high accuracy, 3.5-bit voltage domain MDAC and ...7-bit high-speed time domain ADC (TD-ADC) are combined into a 10-bit hybrid ADC. In the first stage MDAC, a low-power push-pull amplifier is used to improve settling speed, and 1-bit redundancy is designed for calibration and dither injection. The TD-ADC with selective time domain quantization is implemented by a constant-current voltage to time converter (VTC) array and a direct positive feedback time domain comparator. The proposed VTC array can maintain high linearity with a large input swing in high-speed application. The prototype ADC was fabricated in a 28-nm CMOS process and occupied a core area of 0.074 mm 2 . Under a 0.95-V power supply, the chip achieves a measured peak SNDR of 53.2 dB and SFDR of 61.7 dB respectively at conversion rate up to 2.5 GS/s. The FOM is 48.2 fJ/conversion-step.
This work presents an ultralow-power 10-bit 200-kS/s single-ended successive approximation register (SAR) analog-to-digital converter (ADC) for implantable biosensor applications. A high energy- and ...area-efficient switching scheme is proposed, which realizes 95.4% energy saving in a digital-to-analog converter (DAC) switching and two times DAC area reduction compared to the conventional single-ended SAR ADC. The common-mode variation in the proposed scheme is input-independent, resulting in a reduced dynamic offset and harmonic distortion. Besides, a low offset and low kickback noise dynamic comparator with P-type input pair is realized. The prototype is fabricated in 65-nm CMOS technology, consuming 94 nW at 0.6-V supply and occupying a 0.02-mm 2 active area. With the Nyquist input frequency, it achieves the signal to noise and distortion ratio (SNDR) of 56.42 dB, leading to a Walden figure of merit (FoM) of 0.87 fJ/conv.-step.
In this brief, a dual-supply two-stage op-amp is proposed for a 12-b 1 GS/s pipeline ADC, which is composed of a low-voltage supply pre-amplifier and a high-voltage supply amplifier. Its closed-loop ...bandwidth reaches to 5.2 GHz, and the phase margin is larger than 60°. The closed-loop amplifier can settle to 99.95% accuracy within 230 ps, which satisfies the harsh requirements of the first-stage MDAC. The proposed op-amp was employed in a single-channel 12-b 1 GS/s pipeline ADC. The ADC is powered by 1.3 V and the op-amp is powered by dual-supply voltage of 1.3 V and 2.5 V. The ADC fabricated in 65 nm CMOS process consumes 360 mW at 1 GS/s. It achieves an SNDR of 61.9 dB and an SFDR of 72.6 dB with 30 MHz input signal, while maintaining an SNDR > 56.0 dB and SFDR > 69.0 dB in the entire 500 MHz Nyquist band.
This article presents a background calibration method for timing skew in time-interleaved (TI) analog-to-digital converters (ADCs). The timing skew is detected by the frequency fitness genetic ...algorithm (FFGA) and compensated by digital finite impulse response (FIR) differentiators. This method does not require any reference channel and can converge the estimated timing skew in each channel independently. Compared with conventional calibration methods, the convergence time of this method has been reduced by several times. As a chromosome contains multiple estimated timing skew values, this method can be extended to an arbitrary interleaving factor. The all-digital structure applies to advanced technology processes. The effectiveness of the proposed method is presented through numerical simulation and measurement results. It shows that after timing skew calibration, the spurious free dynamic range (SFDR) and signal-to-noise and distortion ratio (SNDR) of a commercial 3.6-GS/s four-channel TI-ADC are improved by 29.5 and 16.9 dB, respectively.
This article presents a high-speed time-domain (TD) 4-bit/cycle successive approximation register (SAR) analog-to-digital converter (ADC). After converting the voltage input to the time domain, the ...compact interpolation-based time-to-digital converter (TDC) resolves 4-bit in each SAR cycle with <inline-formula> <tex-math notation="LaTeX">16\times </tex-math></inline-formula> linear TD interpolation. This scaling-friendly architecture reduces the number of capacitive digital-to-analog converters (CDACs) and voltage-to-time converters (VTCs) significantly, leading to low power, small area, low kickback noise, and small input loading. A cascade current-starved inverter based VTC is used in the second SAR conversion cycle, which improves voltage-to-time gain and ensures speed and linearity. Besides, to reduce the TD interpolation error and eliminate the short-circuit current, a novel phase interpolator is proposed. A two-way time-interleaved 7-bit 3.8-GS/s prototype ADC was fabricated in a 28-nm CMOS, occupying an active area of 0.01 mm2. With a Nyquist input, the measured signal-to-noise and distortion ratio (SNDR) and spurious-free dynamic range (SFDR) are 39.9 and 50.8 dB, respectively. Consuming 7.5 mW at 1.0 V supply, the Walden figure of merit (FoMw) is 24.4 fJ/conversion-step.
