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991.
光纤表面等离子体波共振温度传感器的研究   总被引:3,自引:1,他引:3  
曾捷  梁大开  曹振新 《中国激光》2004,31(7):38-842
根据液体折射率随温度变化而改变的特性,提出了一种基于表面等离子体波共振(SPR)效应的新型光纤温度传感器,分析了表面等离子体波共振光纤探头感应环境温度变化的原理。对表面等离子体波共振探头结构进行了优化设计,并进行了相关实验,为实现高折射率液体介质的感温测试和扩大测温范围提供依据。通过自行设计的一套光纤温度传感测试系统,得到系统输出的表面等离子体波共振光谱信号随温度变化的特性曲线,并提出对共振波长和最小光强反射率进行实时双参数测量的方法。实验结果表明,该测试系统具有结构简单、全光纤化、易远程测量等优点。  相似文献   
992.
基于工作在亚阈值区的MOS器件,运用CMOS电流模基准对CATA和PTAT电流求和的思想.提出一种具有低温漂系数、高电源抑制比(PSRR)的CMOS电压基准源,该电路可同时提供多个输出基准电压,且输出电压可调。该基准源基于CSMC0.5μm标准CMOS工艺,充分利用预调节电路并改进电流模基准核心电路。使整个电路的电源抑制比在低频时达到122dB,温度系数(TC)在0-100℃的温度范围内约7ppm/℃。  相似文献   
993.
介绍IR2110驱动模块的特点.针对其存在的一些不足.给出相关解决方案。设计相应的优化驱动电路,较好地改善IR2110的驱动和保护性能,增强其实用性。  相似文献   
994.
Objective:The aim of the study was to explore the application of 64-slice spiral computed tomography perfusion imaging (CTPI) in evaluating angiogenesis in human osteosarcoma.Methods:Twenty-six patients (18 males and 8 females ranging from 9 to 56 years old,with an average of 19 years) with osteosarcoma underwent 64-slice spiral CTPI.We analyzed the correlations of CTPI parameters including blood flow (BF),blood volume (BV),time to peak (TTP),and permeability surface (PS) with the expression of markers of angiogenesis.Statistical analysis was performed with paired-samples t test,and Pearson correlation analysis was employed to investigate the correlations of CTPI parameters with microvessel density (MVD).Results:Mean BF,BV,TTP,and PS values of osteosarcoma group were (46.6 ± 25.1) mL/100 g/min,(61.8 ± 29.5) mL/100 g,(122.9 ± 26.2) seconds,and (44.5 ± 14.6) mL/100 g/min,respectively.Those in the normal muscle group were (5.2 ± 6.6) mL/100 g/min,(9.6 ± 7.3) mL/100 g,(115.5 ± 33.1) seconds and (17.0 ± 29.3) mL/100 g/min,respectively.Osteosarcoma group showed higher BF,BV and PS compared with the normal muscle group (P = 0.000,P = 0.000,and P = 0.000,respectively).However,no significant difference was found in TTP between osteosarcoma tissue and normal adjacent muscle tissue (P = 0.273).BF,BV,and PS were positively correlated with MVD (r = 0.83,P = 0.000;r = 0.87,P = 0.000;and r = 0.63,P = 0.001,respectively).No correlation was found between TTP and MVD (r = –0.02,P = 0.93).Conclusion:CTPI is useful for assessing tumor vascularity of osteosarcoma and CTPI parameters are positively correlated with MVD.  相似文献   
995.
With two-body unitarity equations, we demonstrate the relation between the data of Dalitz analysis of a D+ → K^-π+π+ decay experiment and that of Kπ scattering, and point out that there might be some underestimated ambiguity in the existing data sets, if  相似文献   
996.
Metallurgical and Materials Transactions A - One key challenge for tailoring microstructure of high-speed steel (HSS) is to obtain small-sized carbides with a homogeneous distribution. Although...  相似文献   
997.
Cu-30Ni-xRE(x=0-0.213 wt.%) alloy was prepared by adding rare earths(RE) in melted Cu-30Ni alloy using metal mould casting method.The effects of RE on corrosion resistance of the alloy in simulated seawater were investigated using optical microscope,scanning electronic microscope with energy-dispersive spectrometer and electrochemical measurement system.The results showed that the corrosion resistance of Cu-30Ni alloy was greatly improved by adding proper amount of RE,whereas excess addition of RE worsened ...  相似文献   
998.
A low-voltage feedforward ring voltage-controlled oscillator (FRVCO) withstanding process variation and supply-voltage noise is proposed in this paper. In this design, the variation of transistors’ threshold voltages and supply voltage noise are detected by a compensating voltage generated circuit, and the load capacitance of the FRVCO is tuned by the compensating voltage to reduce the variation of oscillating frequency. Simulation results demonstrate that the centre oscillating frequency difference between ‘FF’ and ‘SS’ corners is reduced from 38.3% to 1.5% by tuning the voltage from 0 to 650 mV. Moreover, with a supply voltage change of ±0.5%, the frequency variation is smaller than ±0.06%. The 0.65-V 600-MHz FRVCO has been fabricated using the TSMC 130-nm CMOS process.  相似文献   
999.
Three-dimensional (3D) multiple-input multiple-output (MIMO) systems exploit spatial richness and provide another degree of freedom to transmit signals and eliminate spatial interference. Currently, however, there is no 3D codebook for two-dimensional (2D) antenna array MIMO systems with limited feedback. In this paper, based on the existing 2D codebook, we present a limited feedback and transmission scheme for 2D antenna array MIMO systems. In this scheme, the mobile station (MS) has imperfect channel knowledge, and the base station (BS) only acquires partial information relating the channel instantiation. MS must feed back two channel state information (CSI) instances, i.e., the horizontal and vertical CSIs. After receiving the two CSI instances, the BS interpolates a new vertical precoding vector using the vertical CSI. Then, the BS re-constructs a 3D beamforming vector using horizontal and vertical precoding vectors and compensates the reported horizontal channel quality indicator. System level simulation is employed, and the simulation results show that the proposed method improves the system spectral efficiency and the cell-edge SE significantly.  相似文献   
1000.
Recently, much attention has been drawn to distributed antenna systems (DAS), which are proposed to improve the performance of mobile communication systems. This paper focuses on the analysis of the average symbol error rate (SER) of DAS over a generic composite channel. Initially, a new composite channel model is considered for DAS, which is a mixture of path loss, lognormal shadowing and generalized-Gamma fast fading. This composite channel model is a generic model, which includes many well-known composite channel models as special cases. Based on the channel model, the cumulative distribution function of the output signal-to-noise ratio is obtained by employing selective transmission scheme. Moreover, by averaging the channel conditions and the positions of the MS in the cell, an approximate expression of the average SER is derived, which is a unified form of expression for many commonly used modulation schemes. Numerical results show that the derived expression of the average SER can provide sufficient precision for evaluating the SER performance of DAS under different modulation schemes.  相似文献   
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