茜素红修饰电极对肾上腺素的测定

采用电化学聚合法制备了茜素红修饰玻碳电极,该修饰电极对肾上腺素(EP)有明显的电催化特性。在pH7.6的磷酸缓冲溶液(PBS)中,抗坏血酸(AA)和EP在修饰电极上的电位分别为-0.124V和0.192V。电位差达到300mV,且在高浓度AA的存在下可以实现对EP的测定。EP在该电极上检测的线性范围是5.0×10-7~1.0×10-4mol/L,检测下限为3.6×10-8mol/L。该法可用于针剂EP样品测定。     

基于51单片机的边界扫描控制器的设计与实现

为提高现代军事装备的故障检测能力,运用VC++软件编辑控制界面,设计并制作了一种基于51系列单片机的边界扫描控制器;该控制器由USB转串口电路和单片机构成,结构简单、通用性强且成本低廉;将PC机发送的测试指令或数据进行USB与JTAG协议转换,产生符合IEEE1149.1标准的JTAG总线信号;以EPM7128芯片为测试对象,注入JTAG信号并采集测试响应,实现了对基于测试芯片硬件电路的故障检测;测试结果表明:设计的边界扫描控制器可实现对单芯片和芯片级联的边界扫描状态的控制,能避开可编程芯片的内部逻辑程序控制,完成对可编程芯片及其外围电路的故障检测。     

基于Duffing振子的变尺度微弱特征信号检测方法研究

研究了Holmes型Duffing方程的混沌特性用于信号检测的方法,针对该方法只适用检测特定频率成分信号、方程参数选择不便以及噪声影响检测结果等情况,提出基于Duffing振子的变尺度微弱特征信号检测方法. 数值分析表明,该方法可以仅用一组确定的参数条件,检测任意频率、任意相位的特征信号.     

一种用于短距离无线通信的低功耗多频带可配置收发机

A reconfigurable multi-mode multi-band transceiver for low power short-range wireless communication applications is presented.Its low intermediate frequency(IF) receiver with 3 MHz IF carrier frequency and the direct-conversion transmitter support reconfigurable signal bandwidths from 250 kHz to 2 MHz and support a highest data rate of 3 Mbps for MSK modulation.An integrated multi-band PLL frequency synthesizer is utilized to provide the quadrature LO signals from about 300 MHz to 1 GHz for the transceiver multi-band application. The transceiver has been implemented in a 0.18μm CMOS process.The measurement results at the maximum gain mode show that the receiver achieves a noise figure(NF) of 4.9/5.5 dB and an input 3rd order intermodulation point(IIP3) of-19.6/-18.2 dBm in 400/900 MHz band.The transmitter working in 400/900 MHz band can deliver 10.2/7.3 dBm power to a 50Ωload.The transceiver consumes 32.9/35.6 mW in receive mode and 47.4/50.1 mW in transmit mode in 400/900 MHz band,respectively.     

用于77GHz毫米波雷达的模拟基带电路设计

实现了一个带宽和增益可配置、高线性度、低噪声的模拟基带电路,可应用于77 GHzCMOS毫米波雷达接收机.电路包括一个带宽可配置的5阶巴特沃斯低通滤波器模块、三个可编程增益放大器模块以及三个直流失调消除环路.增益范围为18～70 dB,增益步进为6 dB;带宽为200 kHz～2 MHz;噪声系数最小为24 dB;输出1-dB压缩点为5.1 dBm,在最高增益时,IIP3为-52dBm;功耗为14.6 mA@1 V.电路采用65 nm CMOS工艺实现,芯片面积为1.2×0.93 (mm2).     

Coumarinolignans with Reactive Oxygen Species (ROS) and NF-κB Inhibitory Activities from the Roots of Waltheria indica

Seven new coumarinolignans, walthindicins A–F (1a, 1b, 2–5, 7), along with five known analogs (6, 8–11), were isolated from the roots of Waltheria indica. The structures of the new compounds are determined by detailed nuclear magnetic resonance (NMR), circular dichroism (CD) with extensive computational support, and mass spectroscopic data interpretation. Compounds were tested for their antioxidant activity in Human Cervical Cancer cells (HeLa cells). Compounds 1a and 6 showed higher reactive oxygen species (ROS) inhibitory activity at 20 μg/mL when compared with other natural compound-based antioxidants such as ascorbic acid. Considering the role of ROS in nuclear-factor kappa B (NF-κB) activation, compounds 1a and 6 were evaluated for NF-κB inhibitory activity and showed a concentration-dependent inhibition in Human Embryonic Kidney 293 cells (Luc-HEK-293).     

陕南茶叶及其产地土壤中微量元素含量的测定

采用微波消解一火焰原子吸收光谱法测定了陕南茶叶及其栽培土壤中Zn、Fe、Cu、Cr、Pb5种微量元素的含量,以指导茶农合理施肥,提高陕南地区茶叶品质。结果表明,茶叶与土壤中矿质元素的含量呈一定的正相关性,不同产地的茶叶和土壤中微量元素的含量有一定的差异;茶叶和土壤中Zn、Fe元素的含量较高,而对人体健康有影响的Pb元素含量低于国家允许标准。     

A vector quantization based approach for CFA data compression in wireless endoscopy capsule

A novel approach for near-lossless compression of Color Filtering Array （CFA） data in wireless endoscopy capsule is proposed in this paper. The compression method is based on pre-processing and vector quantization. First, the CFA raw data are low pass filtered and rearranged during pre-processing. Then, pairs of pixels are vector quantized into macros of 9 bits by applying block partition and index mapping in succession. These macros are entropy compressed by Joint Photographic Experts Group-Lossless Standard （JPEG-LS） finally. The complex step of codeword searching in Vector Quantization （VQ） is avoided by a predefined partition rule, which is suitable for hardware implementation. By control of the pre-processor and VQ scheme, either high quality compression under unfiltered case or high ratio compression under filtered case can be realized, with the average Peak Signal-to-Noise Ratio （PSNR） more than 43dB and 37dB respectively. Compared with the state-of-the-art method and the previously proposed method, our compression approach outperforms in compression performance as well as in flexibility.     

原位缩聚法制备碳纳米管/尼龙11复合材料

用原位缩聚法制备了碳纳米管增强的尼龙11复合材料,用X射线衍射仪、红外(FTIR)、扫描电镜(SEM)、热重(TGA)、机械拉伸测试仪等对其结构、形貌、热性能及机械性能进行了表征测试.扫描电镜结果显示碳纳米管均一地分散在尼龙11/碳纳米管复合材料中.复合材料的拉伸模量比纯尼龙11有较大的提高.当复合材料中碳纳米管含量分别为1%,5%,10%时,材料的拉伸模量分别提高了34.5%,92.9%和113,7%.同时,复合材料的储能模量也有提高.热分析结果显示当复合材料中碳纳米管含量为1%时,其失重5%和10%的温度分别由纯尼龙11的404℃、424℃提高到414℃和437℃.示差扫描量热分析(DSC)显示复合材料的结晶温度随碳纳米管的加入而升高,而结晶度则降低.