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The traditional nearfield acoustic holography (NAH) requires free field on the side of the hologram plane back to the target sound source. There are often acoustic reflection and scattering caused by the interference source or the wall in the wind tunnel test, which greatly limits the application of NAH. By processing the sound signal measured by the planar microphone array, the target source and the interference source can be separated to achieve the purpose of indirectly removing the background interference. Aiming at the situation that the target sound source and the hologram are located inside and outside the wind tunnel jet respectively, combined with the convective wave equation solution in moving fluid medium and the classical shear layer correction theory, the spatial Fourier transform-based separation using single hologram is corrected. The target sound source inside the jet and the interference sound source outside the jet are separated, leading to the acoustic parameters of the target sound source acting on the hologram plane alone. Numerical simulations show that the change of working parameters has little effect on the separation results. The separation errors under different conditions are small, and the method has a certain anti-interference ability.

Electromagnetically induced transparency (EIT) is widely studied in atomic systems and metamaterials. However, there are few studies of EIT on topological insulator (TI). In this paper, the EIT effect is studied in TI which is placed on the dielectric substrate by finite difference time domain (FDTD) method. We discussed the effective permittivity of TI layer on different temperature at terahertz (THz) range. The EIT-like phenomenon can be obtained at transverse electromagnetic (TE) and transverse magnetic (TM) mode. The parameters of dielectric substrate and TI layer are investigated to tune the EIT phenomenon. Moreover, incident angle of electromagnetic (EM) wave is also studied to influence the transmission of the structure. The result was shown the large incident angle and polarization insensitive EIT effect can be realized. The results can provide some potential applications such as terahertz switches, filters and terahertz communications.

A two channel time-interleaved 14-bit 500MS/s charge domain pipelined ADC with mix-signal for-ground mismatch calibration method based on binary search is proposed. The offset and gain error mismatch between the two channels are calibrated in the mix-signal for-ground calibration. The 14-bit 500MS/s charge domain pipelined ADC is designed and realized in a 1P6M 0.18$\mu$m CMOS process. Test results show the 14-bit 500MS/s ADC achieves the signal-to-noise ratio of 69.8 dBFS and the spurious free dynamic range of 82.3dB, with 72.1MHz input at 500MS/s, while consumes the power consumption of 365mW.

In this paper, a power-adaptable method for LTE is proposed and applied to a pipeline analog-to-digital converter (ADC). A current adaptable generator was integrated in the chip to change the currents of the amplifiers and comparators by SPI. When the input frequency is 0.7 MHz and 1.5 MHz, D1D0 of interface control word is set to 00 and 01, then the current adaptable generator is 2 µA and 4 µA, respectively; When the input frequency is 10 MHz, D1D0 of interface control word is set to 11, then the current adaptable generator is 8 µA, then the converter can maintains the good performance and avoid an bit-error rate due to the quantization of ADC. The ADC fabricated in a 0.13 µm CMOS process. The measured DNL and INL are +0.4/−0.43LSB and +0.67/−0.91LSB. SFDR and SNDR are 65.3 dB and 52.4 dB, respectively.

In this paper, a digital background error-correction technique for pipelined successive approximation analogue-to-digital converter (SAR ADC) based on Least Mean Square (LMS) algorithm is presented. This technique uses a slow but accurate ADC as a reference ADC and combines with LMS algorithm to calibrate the capacitor mismatch, gain error, reference voltage offset error of the inaccurate pipelined SAR ADC. The simulation validates the effectiveness of this technique for a pipelined SAR ADC with 16 bit resolution. The effective number of bits(ENOB) is improved from 10.31 bits to 15.66 bits.

This paper proposes an adaptive digital background error-correction technique to calibrate analog-to-digital converters (ADCs). The new approach combines an adaptive recursive-least-squares (RLS) algorithm-based FIR filter and an accurate reference ADC. Matlab simulation indicates that the proposed RLS filter is sufficient to remove the effect of large differential and integral nonlinearities resulting from component errors including capacitor mismatch, finite op-amp gain, op-amp offset and sampling-switch-induced offset. With a 100MHz sinusoidal input, the ENOB can be increased from 8.56bit to 15.55bit, the peak SNR can be increased from 53.29dB to 59.35dB and the SFDR can be increased from 56.52dB to 119.26dB.

A novel 24-sided concave-convex geometry monolithic transformer that has high self-resonant frequency and quality factor is presented. It is implemented with the top level thick Cu metal and multiple geometrical structures in 0.13 um CMOS mixed-signal 1P6M salicide back-end process. Compared to those with conventional square, hexagonal and octagonal geometry structure, the novel transformer achieves better quality factor, self-resonant frequency and less chip area. The simulation results show that 1.12, 1 and 0.58 GHz improvements in SRF, and 2.4, 0.9 and 0.3 enhancements in quality factor are obtained respectively when compared to typical square, hexagonal and octagonal transformer with the same inductance of the primary and secondary winding.

An 8-bit single-input successive approximation register (SAR) analog-to-digital converter (ADC) for long term evolution (LTE) system with an internal ring oscillator is implemented. A novel 5-bit resistor and 3-bit capacitor segment digital-to-analog converter (DAC) is used to minimize the chip area. The design was fabricated in a 0.13 µm CMOS process with an area of 0.1mm2 and a power of 1.2 mW. The measurement results show that the DNL and INL of the proposed ADC are +0.11/•0.18 LSB and +0.8/•0.04 LSB respectively. The SFDR and SNDR can get 53 dB and 43.3 dB respectively.

To prevent or limit flexural cracking in the negative moment region normally with a spiky rise and rapid reversal, a stiffened steel-concrete composite section (SCPR) was proposed The proposed section was composed of concrete and steel plate with perforated stiffening rib plate to reduce the dependency of shear transfer on interfacial bond. Eight scale specimens were tested for comparison. Six specimens were reinforced using steel plate with perforated stiffening rib plates, one specimen was reinforced using conventional reinforcing bars and one specimen was reinforced using epoxy-bonded steel plate for comparison. All beam specimens were tested to failure. The test results indicated the steel plate with rib stiffeners can offer a pronounced improvement to the cracking resistance of the concrete. The cracking load for the SCPR specimen with stiffening rib plate is three times higher than the specimen reinforced with conventional steel, and two and a half times higher than specimen reinforced with epoxy-bonded steel plate. The cracking mechanism of the SCPR beams was discussed in the paper.

This paper presented an innovative use of a variable steel-concrete composite section for the main arch ribs to take combined advantages of steel and concrete strength. And vertical erection method that can significantly simplify and accelerate arch bridge construction with better structure integrity and higher stability during construction is developed. Since steel construction is superior to RC due to its advantages of high strength to weight ratio, offsite prefabrication and quick on-the-spot assembly, the use of steel box as the stiffening core of arch rib section becomes an ideal choice for the initial arch framing using the developed erection method. The prefabricated steel box can be erected vertically on temporarily restrained horizontal hinge device at the spring line with minimal hoisting equipments. The completed two half-leaf can then rotate down on its own weight to meet at the mid-span for closure in a few hours. The completed steel arch frame can serve as formwork and supporting system to provide a sufficient and safe platform for the placement of concrete that forms a variable composite rib section, and for erection of spandrel columns and deck system. This construction technique and structure optimization can significantly simplify and speed up arch bridge construction with increased work zone safety and better constructability, thus provides a viable solution for arch bridge construction with difficult site condition. Pilot project, a 75-meter highway bridge, was presented to demonstrate the basic concept, design features, general construction technology.

The aim of this study is to assess log quality and extract the internal defects information from a log x-ray image with fractal and mathematical morphology method. Firstly, the log image is divided into sub areas, calculate the multi-scale fractal feature (D MF ) of each sub areas, the D MF values of different regions in a log image are normally different. According to the values of D MF the internal defects in log can be detected and classified. In order to obtain more continuous edges of the defects in log x-ray image, mathematical morphology theory was also applied in this paper and square structuring element is selected to do a further processing. The experimental result show that, compare to the traditional methods, the method for edge detection of the image based on fractal and mathematical morphology, achieved a better anti-noise performance and preserving the useful defects detail of the log x-ray image effectively.

nt t t t t , , 2 , 1 , 2 2 1 1 � = + + = − − e μ φ μ φ μ in which the parameters have a special relationship 2 1 2 φ φ = . For the properties of variance-covariance matrix Σ , This kind of models are transformed into the standard linear regression models without autocorrelation errors and apply the method of cycle generalized least squares (CGLS) to estimate parameters. Simulation results show that efficiency of CGLS method is superior over the method of generalized least squares (GLS) under mean square error criterion.

This paper proposes a scheme for nondestructive detection of blockboard. According to intensity differences of the x-ray through the blockboard, a lot of valuable target information such as bond quality, uniformity degree, and situations of filler were detected. First of all, x-ray nondestructive system was used to detect blockboard and the blockboard image was obtained. And then some image pre-processing methods just as function imadjust and value filter are employed to enhance the valuable target information in blockboard image. Then, mathematical morphology double-gradient algorithm was used in edge detection of blockboard image. Experimental results demonstrate that the method performs better in noise- suppression and edge detection than conventional edge detection operations. This study provides a new tool for nondestructive detection of blockboard.

D ) was applied in this paper. The MF D values of different regions in a medical image are normally different. According to the values of the MF D , small lesions in a medical x-ray image can be detected. This method has been applied to a digital bone fracture x-ray image. Experimental result showed that the MF D values of the background regions are between 0.005 and 0.020; the MF D values of the normal regions are between 0.040 and 0.070; and the MF D values of the

The aim of this study is to extract the internal defects information from a log x-ray image and accurately identify the types of the defects in log by digital image processing technology and fractal theory. A method in log x-ray image defects detection based on multi-scale fractal feature (DMF) was applied in this paper. The DMF values of different regions in a log image are normally different. According to the values of DMF, the internal defects in log can be detected and classified. This method has been applied to the log image with crack and knots, the experimental result show that the DMF values of the normal regions are between 0.020 and 0.060; the DMF values of the crack regions are between 0.300 and 0.600; and the DMF values of the knot regions are between 0.100 and 0.200. This study provides a new tool for analyzing and processing log x-ray image.