Cymbal hydrophones have small volume and high sensitivity, but their reception is not stable enough, and their reception is in too narrow a frequency band. In order to overcome these inadequacies, the structure of the...Cymbal hydrophones have small volume and high sensitivity, but their reception is not stable enough, and their reception is in too narrow a frequency band. In order to overcome these inadequacies, the structure of the cymbal hydrophone was improved. The single ceramic piezoelectric element was replaced with a double one, the radius of the ceramic piezoelectric element was reduced, and a parallel circuit was added. A static analysis of this new structure was developed, and then simulations were made of both the traditional and new hydrophone structure using finite element software. Tests were then conducted in a tank. The results showed that the improved hydrophone has reception in a wider frequency band, reception performance is stable within this frequency band, and sensitivity is still high.展开更多
An "automatic power down" method is introduced to design a 4/5 prescaler,with the characteristic of making one of its D-flip-flops power down when it operates in divide-by-4 mode. Implemented with the TSMC 0.25vm mi...An "automatic power down" method is introduced to design a 4/5 prescaler,with the characteristic of making one of its D-flip-flops power down when it operates in divide-by-4 mode. Implemented with the TSMC 0.25vm mixed-sig- nal CMOS process,the 4/5 MOS current mode logic prescaler is designed with this automatic power down technique. The simulation results show that the new 4/5 prescaler is immune to the "wake-up" issue and thereby retains the same maxi- mum operating frequency as the conventional prescaler. An integer-N divider with this proposed prescaler and with the di- vision ratio 66/67 is manufactured,and it is estimated to save more than 20% of the power compared with the conventional 4/5 prescaler.展开更多
A fractional-N frequency synthesizer for 433/868MHz SRD applications is implemented in a 0.3μm CMOS process. A wide-band VCO and an AFC are used to cover the desired bands. A 3bit third order sigma-delta modulator is...A fractional-N frequency synthesizer for 433/868MHz SRD applications is implemented in a 0.3μm CMOS process. A wide-band VCO and an AFC are used to cover the desired bands. A 3bit third order sigma-delta modulator is adopted to reduce the out-band phase noise. The measurements show a VCO tuning range from 1.31 to 1.88GHz with AFC working correctly,an out-band phase noise of -139dBc/Hz at 3MHz offset frequency, and a fractional spur of less than - 60dBc. The chip area is 1.5mm × 1.2mm and the total current dissipation including LO buffers is 19mA from a single 3.0V supply voltage.展开更多
The frequency in middle of magnon energy band in a five-layer ferromagnetic superlattice is studied by using the linear spin-wave approach and Green's function technique. It is found that four energy gaps and corresp...The frequency in middle of magnon energy band in a five-layer ferromagnetic superlattice is studied by using the linear spin-wave approach and Green's function technique. It is found that four energy gaps and corresponding four frequencie in middle of energy gaps exist in the magnon band along Kx direction perpendicular to the superlattice plane. The spin quantum numbers and the interlayer exchange couplings all affect the four frequencies in middle of the energy gaps. When all interlayer exchange couplings are same, the effect of spin quantum numbers on the frequency wg1 in middle of the energy gap Δw12 is complicated, and the frequency wg1 depends on the match of spin quantum numbers in each layer. Meanwhile, the frequencies wg2, wg3, and wg4 in middle of other energy gaps increase monotonously with increasing spin quantum numbers. When the spin quantum numbers in each layer are same, the frequencies wg1, wg2, wg3, and wg4 all increase monotonously with increasing interlayer exchange couplings.展开更多
The parasitic capacitance effect and its influence to the performance have been investigated in Bi-polar Junction Metal-Oxide-Semiconductor Field-Effect Transistor (BJMOSFET). The frequency characteristic equivalent c...The parasitic capacitance effect and its influence to the performance have been investigated in Bi-polar Junction Metal-Oxide-Semiconductor Field-Effect Transistor (BJMOSFET). The frequency characteristic equivalent circuit and high frequency response model of BJMOSFET have been presented. The frequency characteristic of BJMOSFET is simulated using the multi-transient analytical method and PSPICE9 simulator. The conclusions that BJMOSFET owns less total capacitance, wider frequency band, better transient charac-teristic and better frequency responses are reached by comparing with the traditional MOSFET at the same structure parameters and bias conditions. BJMOSFET, as a novel promising high frequency device, would be desired to find application in future integrated circuit.展开更多
Given multi-resolution decomposition of wavelet packet transforms,wavelet packet frequency band energy has been deduced from different bands of blasting vibration signals.Our deduction reflects the total effect of all...Given multi-resolution decomposition of wavelet packet transforms,wavelet packet frequency band energy has been deduced from different bands of blasting vibration signals.Our deduction reflects the total effect of all three key elements(intensity,frequency and duration of vibration)of blasting vibration. We considered and discuss the dynamic response of structures and the effect of inherent characteristics of controlled structures to blasting vibration.Frequency band response coefficients for controlled structures by blasting vibration have been obtained.We established multi-factor blasting vibration safety criteria,referred to as response energy criteria.These criteria reflect the total effect of intensity, frequency and duration of vibration and the inherent characteristics(natural frequency and damping ratio)of dynamic responses from controlled structures themselves.Feasibility and reliability of the criteria are validated by an example.展开更多
The main cause of dynamic errors is due to frequency response limitation of measurement system. One way of solving this problem is designing an effective inverse filter. Since the problem is ill-conditioned, a small u...The main cause of dynamic errors is due to frequency response limitation of measurement system. One way of solving this problem is designing an effective inverse filter. Since the problem is ill-conditioned, a small uncertainty in the measurement will came large deviation in reconstncted signals. The amplified noise has to be suppressed at the sacrifice of biasing in estimation. The paper presents a kind of designing method of inverse filter in frequency domain based on stabilized solutions of Fredholm integral equations of the fast kind in order to reduce dynamic errors. Compared with previous several work, the method has advantage of generalization. Simulations with different Signal-to-Noise ratio (SNR) are investigated. Flexibility of the method is verified. Application of correcting dynamic error is given.展开更多
AIM:To evaluate the possible relationship between the Ku80 gene polymorphism and the risk of gastric cancer in China.METHODS:In this hospital-based case-control study of gastric cancer in Jiangsu Province,China,we inv...AIM:To evaluate the possible relationship between the Ku80 gene polymorphism and the risk of gastric cancer in China.METHODS:In this hospital-based case-control study of gastric cancer in Jiangsu Province,China,we investigated the association of the Ku80 G-1401T (rs828907) polymorphism with gastric cancer risk.A total of 241 patients with gastric cancer and 273 age-and sexmatched control subjects were genotyped and analyzed by polymerase chain reaction-restriction fragment length polymorphism.RESULTS:The frequencies of genotypes GG,GT and TT were 65.6%,22.8% and 11.6% in gastric cancer cases,respectively,and 75.8%,17.6% and 6.6% in controls,respectively.There were significant differences between gastric cancer and control groups in the distribution of their genotypes (P=0.03) and allelic frequencies (P=0.002) in the Ku80 promoter G-1401T polymorphism.CONCLUSION:The T allele of Ku80 G-1401T may be associated with the development of gastric cancer.展开更多
This paper describes the finite element (FE) analysis technique to predict fatigue life using the narrow band frequency response approach. The life prediction results are useful for improving the component design meth...This paper describes the finite element (FE) analysis technique to predict fatigue life using the narrow band frequency response approach. The life prediction results are useful for improving the component design methodology at the very early development stage. The approach is found to be suitable for a periodic loading but requires very large time records to accurately describe random loading processes. This paper is aimed at investigating the effects of surface treatments on the fatigue life of the free piston linear engine’s components. Finite element modelling and frequency response analysis were conducted using computer aided design and finite element analysis commercial codes, respectively. In addition, the fatigue life prediction was carried out using finite element based fatigue analysis commercial code. Narrow band approach was specially applied to predict the fatigue life of the free piston linear engine cylinder block. Significant variation was observed between the surface treatments and untreated cylinder block of free piston engine. The obtained results indicated that nitrided treatment yielded the longest life. This approach can determine premature products failure phenomena, and therefore can reduce time to market, improve product reliability and customer confidence.展开更多
Hydrogen-free diamond-like carbon (DLC) thin films were deposited at low temperature (less than 100~C) by an RF magne- tron sputtering facility. DLC films have the ability to change the sound velocity (E/p) in l...Hydrogen-free diamond-like carbon (DLC) thin films were deposited at low temperature (less than 100~C) by an RF magne- tron sputtering facility. DLC films have the ability to change the sound velocity (E/p) in loudspeakers for applications of hard coating. The hydrogen-free DLC films were coated onto PEI diaphragm substrates. The ID/IG ratio and the surface roughness are 2.09 and less than 0.86 nm (Ra) with a scanning area of 50 um x 50 um, respectively. Frequency response analysis of the DLC films on the diaphragm shows that the high frequency response increases by 0.2 dB-5.1 dB (6 kHz-ll.2 kHz), -0.4 dB-1.8 dB (11.8 kHz-20 kHz) on average. On the basis of the results of this study, we validated that it was feasible to sputter hydrogen-free DLC films on polymer substrates for mass production. These results also provided useful parameters for future applications of electro-acoustic devices.展开更多
文摘Cymbal hydrophones have small volume and high sensitivity, but their reception is not stable enough, and their reception is in too narrow a frequency band. In order to overcome these inadequacies, the structure of the cymbal hydrophone was improved. The single ceramic piezoelectric element was replaced with a double one, the radius of the ceramic piezoelectric element was reduced, and a parallel circuit was added. A static analysis of this new structure was developed, and then simulations were made of both the traditional and new hydrophone structure using finite element software. Tests were then conducted in a tank. The results showed that the improved hydrophone has reception in a wider frequency band, reception performance is stable within this frequency band, and sensitivity is still high.
文摘An "automatic power down" method is introduced to design a 4/5 prescaler,with the characteristic of making one of its D-flip-flops power down when it operates in divide-by-4 mode. Implemented with the TSMC 0.25vm mixed-sig- nal CMOS process,the 4/5 MOS current mode logic prescaler is designed with this automatic power down technique. The simulation results show that the new 4/5 prescaler is immune to the "wake-up" issue and thereby retains the same maxi- mum operating frequency as the conventional prescaler. An integer-N divider with this proposed prescaler and with the di- vision ratio 66/67 is manufactured,and it is estimated to save more than 20% of the power compared with the conventional 4/5 prescaler.
文摘A fractional-N frequency synthesizer for 433/868MHz SRD applications is implemented in a 0.3μm CMOS process. A wide-band VCO and an AFC are used to cover the desired bands. A 3bit third order sigma-delta modulator is adopted to reduce the out-band phase noise. The measurements show a VCO tuning range from 1.31 to 1.88GHz with AFC working correctly,an out-band phase noise of -139dBc/Hz at 3MHz offset frequency, and a fractional spur of less than - 60dBc. The chip area is 1.5mm × 1.2mm and the total current dissipation including LO buffers is 19mA from a single 3.0V supply voltage.
基金Supported by the Natural Science Foundation of Liaoning Province of China under Grant No. 20062040
文摘The frequency in middle of magnon energy band in a five-layer ferromagnetic superlattice is studied by using the linear spin-wave approach and Green's function technique. It is found that four energy gaps and corresponding four frequencie in middle of energy gaps exist in the magnon band along Kx direction perpendicular to the superlattice plane. The spin quantum numbers and the interlayer exchange couplings all affect the four frequencies in middle of the energy gaps. When all interlayer exchange couplings are same, the effect of spin quantum numbers on the frequency wg1 in middle of the energy gap Δw12 is complicated, and the frequency wg1 depends on the match of spin quantum numbers in each layer. Meanwhile, the frequencies wg2, wg3, and wg4 in middle of other energy gaps increase monotonously with increasing spin quantum numbers. When the spin quantum numbers in each layer are same, the frequencies wg1, wg2, wg3, and wg4 all increase monotonously with increasing interlayer exchange couplings.
基金Supported by the Hunan Provincial Natural Science Foundation (No.05JJ30115).
文摘The parasitic capacitance effect and its influence to the performance have been investigated in Bi-polar Junction Metal-Oxide-Semiconductor Field-Effect Transistor (BJMOSFET). The frequency characteristic equivalent circuit and high frequency response model of BJMOSFET have been presented. The frequency characteristic of BJMOSFET is simulated using the multi-transient analytical method and PSPICE9 simulator. The conclusions that BJMOSFET owns less total capacitance, wider frequency band, better transient charac-teristic and better frequency responses are reached by comparing with the traditional MOSFET at the same structure parameters and bias conditions. BJMOSFET, as a novel promising high frequency device, would be desired to find application in future integrated circuit.
基金provided by the National Natural Science Foundation of China(No.51064009)the National 11th Five-Year Science & Technology Program of China (No.2008BAB32B03)+1 种基金the Natural Science Foundation of Jiangxi Province(No.2009GQC0036)the Youth Science Foundation of Education Department of Jiangxi Province(No.GJJ09515)
文摘Given multi-resolution decomposition of wavelet packet transforms,wavelet packet frequency band energy has been deduced from different bands of blasting vibration signals.Our deduction reflects the total effect of all three key elements(intensity,frequency and duration of vibration)of blasting vibration. We considered and discuss the dynamic response of structures and the effect of inherent characteristics of controlled structures to blasting vibration.Frequency band response coefficients for controlled structures by blasting vibration have been obtained.We established multi-factor blasting vibration safety criteria,referred to as response energy criteria.These criteria reflect the total effect of intensity, frequency and duration of vibration and the inherent characteristics(natural frequency and damping ratio)of dynamic responses from controlled structures themselves.Feasibility and reliability of the criteria are validated by an example.
基金The paper is sponsored by National Natural Science Foundation of China(No.50675211)Natural Science Foundation(No.2009011023)Returned Overseas Graduates Foundation(No.2008067) of Shanxi Provincein China
文摘The main cause of dynamic errors is due to frequency response limitation of measurement system. One way of solving this problem is designing an effective inverse filter. Since the problem is ill-conditioned, a small uncertainty in the measurement will came large deviation in reconstncted signals. The amplified noise has to be suppressed at the sacrifice of biasing in estimation. The paper presents a kind of designing method of inverse filter in frequency domain based on stabilized solutions of Fredholm integral equations of the fast kind in order to reduce dynamic errors. Compared with previous several work, the method has advantage of generalization. Simulations with different Signal-to-Noise ratio (SNR) are investigated. Flexibility of the method is verified. Application of correcting dynamic error is given.
基金Supported by Grants from the National Natural Science Foundation of China,No. 30672486the Natural Science Foundation of Jiangsu Province,No. BK2006525"333 Project" and "Qinglan Project" Funds for the Young Academic Leader of Jiangsu Province to Wang B
文摘AIM:To evaluate the possible relationship between the Ku80 gene polymorphism and the risk of gastric cancer in China.METHODS:In this hospital-based case-control study of gastric cancer in Jiangsu Province,China,we investigated the association of the Ku80 G-1401T (rs828907) polymorphism with gastric cancer risk.A total of 241 patients with gastric cancer and 273 age-and sexmatched control subjects were genotyped and analyzed by polymerase chain reaction-restriction fragment length polymorphism.RESULTS:The frequencies of genotypes GG,GT and TT were 65.6%,22.8% and 11.6% in gastric cancer cases,respectively,and 75.8%,17.6% and 6.6% in controls,respectively.There were significant differences between gastric cancer and control groups in the distribution of their genotypes (P=0.03) and allelic frequencies (P=0.002) in the Ku80 promoter G-1401T polymorphism.CONCLUSION:The T allele of Ku80 G-1401T may be associated with the development of gastric cancer.
基金Project (No. 03-02-02-0056 PR0025/04-03) supported by the Inten-sification of Research in Priority Areas (IRPA), Ministry of Science,Technology and Innovation, Malaysia
文摘This paper describes the finite element (FE) analysis technique to predict fatigue life using the narrow band frequency response approach. The life prediction results are useful for improving the component design methodology at the very early development stage. The approach is found to be suitable for a periodic loading but requires very large time records to accurately describe random loading processes. This paper is aimed at investigating the effects of surface treatments on the fatigue life of the free piston linear engine’s components. Finite element modelling and frequency response analysis were conducted using computer aided design and finite element analysis commercial codes, respectively. In addition, the fatigue life prediction was carried out using finite element based fatigue analysis commercial code. Narrow band approach was specially applied to predict the fatigue life of the free piston linear engine cylinder block. Significant variation was observed between the surface treatments and untreated cylinder block of free piston engine. The obtained results indicated that nitrided treatment yielded the longest life. This approach can determine premature products failure phenomena, and therefore can reduce time to market, improve product reliability and customer confidence.
文摘Hydrogen-free diamond-like carbon (DLC) thin films were deposited at low temperature (less than 100~C) by an RF magne- tron sputtering facility. DLC films have the ability to change the sound velocity (E/p) in loudspeakers for applications of hard coating. The hydrogen-free DLC films were coated onto PEI diaphragm substrates. The ID/IG ratio and the surface roughness are 2.09 and less than 0.86 nm (Ra) with a scanning area of 50 um x 50 um, respectively. Frequency response analysis of the DLC films on the diaphragm shows that the high frequency response increases by 0.2 dB-5.1 dB (6 kHz-ll.2 kHz), -0.4 dB-1.8 dB (11.8 kHz-20 kHz) on average. On the basis of the results of this study, we validated that it was feasible to sputter hydrogen-free DLC films on polymer substrates for mass production. These results also provided useful parameters for future applications of electro-acoustic devices.