基于32位高性能嵌入式处理器的门禁考勤系统

随着市场的不断发展，需求的不断提高，门禁考勤系统作为智能化办公室，安防系统的重要部分也在不断发展。但现在的门禁考勤系统多数建立在8位单片机系统基础上 ，具有功能单一，用户界面不友好，不易维护等缺点，因此本文论述了使用Motorola 32位嵌入式处理器MC68VZ328构成的门禁考勤系统，并提出使用32位高性能CPU较之于8位处理器的优势。该门禁考勤系统已经实际正常运行1年多，证明MC68VZ328在门禁考勤系统中的设计是可行，稳定，可靠的。     

Peak‐to‐Average Power Ratio Reduction Using N‐tuple Selective Mapping Method for MC‐CDMA

The multi‐carrier transmission signal in Multi‐Carrier Code Division Multiple Access (MC‐CDMA) has a high peak‐to‐average power ratio (PAPR), which results in nonlinear distortion and deteriorative system performance. An n‐tuple selective mapping method is proposed to reduce the PAPR, in this paper. This method generates 2ⁿ sequences of an original data sequence by adding n‐tuple of n PAPR control bits to it followed by an interleaver and error‐control code (ECC) to reduce its PAPR. The convolutional, Golay, and Hamming codes are used as ECCs in the proposed scheme. The proposed method uses different numbers of the n PAPR control bits to accomplish a noteworthy PAPR reduction and also avoids the need for a side‐information transmission. The simulation results authenticate the effectiveness of the proposed method.     

Finding an Effective Distance Between T-Cell and B-Cell Using S/W ARQ in an Immune System Communication

In this paper,we present the effective distance between T-cell and B-cell in an immune system using Stop and Wait(S/W)Automatic Repeat Request(ARQ).The concentration of the molecules can be increased by increasing the transmitting number of molecules but it may reduce the performance of communication due to higher collision or interference with other molecules.It is also reported in the literature that the concentration of the emitted molecules reduces if the distance from Transmitter(Tx)to Receiver(Rx)increases.Thus,this paper mainly focuses on enhancing the receiver’s capture probability and higher successful complete transmission of the desired molecules by obtaining the effective distance from T-cell to B-cell.In order to find the effective distance,T-cell transmits the molecules 1(Interleukins-2)to B-cell,upon successful reception of molecules 1,antibodies(molecules 2)transmit back to T-cell.Then,the effective distance of an immune system can be obtained after T-cell detects the concentration of the molecules 2 with respect to time.Different schemes of S/W ARQ protocols have implemented in Molecular Communication(MC)but it requires retransmission of duplicate copies due to the lack of addressing an effective distance.Thus,the simulations are performed in MATLAB and the results obtain higher capture probability and also successful complete transmission of the desired molecules.     

Selective and competitive removal of three basic dyes from single,binary and ternary systems in aqueous solutions: A combined experimental and theoretical study

The present study evaluates the selective and competitive adsorption of three basic dyes, namely, Basic blue 9 (BB9), Basic blue 41 (BB41) and Basic yellow 28 (BY28) from single, binary and ternary solutions onto natural safiot clay (NSC). For this, the effect of various parameters such as initial pH, initial dye concentration, adsorbent dose and temperature of the solution was studied and examined in a batch mode. The tested adsorbent was characterized by X-ray fluorescence (XRF), Scanning Electron Microscopy (SEM), Dispersive X-ray spectroscopy (EDX), Fourier Transform Infrared (FT-IR) and X-Ray Diffraction (XRD). XRF results indicate high percentages of SiO₂ (47.44%) and Al₂O₃ (31.24%). X-ray diffraction diffractogram identified kaolinite as the main mineral phase in the presence of quartz, illite, calcite, and dolomite. The adsorption data were examined by Langmuir, Freundlich and Dubinin-Radushkevich isotherms. It was found that for single, binary and ternary systems the results indicated that Langmuir model provided the better correlation of experimental data. The experimental results obtained demonstrate high adsorption efficiency of dyes in the mono and multi systems by NSC. DFT calculations show that BB9 (ω = 6.18) is more electrophilic than BB41 (ω = 4.10) and BY28 (ω = 2.60) which indicates that BB9 is adsorbed first and favored compared to BB41 and BY28. Moreover, Molecular dynamics (MD) and Monte Carlo (MC) simulations are used as a powerful tool to provide a better theoretical scenario for understanding the mode of adsorption on the natural safiot clay (NSC).     

镧对MC3T3细胞钙激活钾电流及其动力学的影响

利用全细胞膜片钳技术,研究了稀土镧离子对非兴奋性小鼠成骨细胞(MC3T3)钙激活外向钾电流及其激活和失活动力学的影响.结果表明:MC3T3细胞钙激活外向钾电流随着电极内液中游离Ca2+浓度的增加而增加,且具有电压和胞内游离Ca2+依赖性特征.细胞外液中的稀土镧可浓度依赖性地抑制MC3T3细胞钙激活外向钾电流,其半数抑制浓度(EC50)为8.23±1.45μmol/L.50μmol/L氯化镧可使钾电流的激活曲线向正电位方向移动,而使其失活曲线向负电位方向移动,但对激活曲线和失活曲线的斜率因子k值影响都不大.研究表明:抑制钾通道电流,可使细胞膜去极化,细胞的兴奋性增加,从而增加胞外Ca2+向胞内流动,引起胞内Ca2+浓度的增加,由此而诱发一系列的生理和分子生物学事件.这一过程可能是稀土镧影响MC3T3成骨细胞生长和功能的分子作用机制之一.     

Osteoblast Adhesion and Proliferation on Poly(3‐octylthiophene) Thin Films

In this study we assessed the suitability of semiconducting P3OT thin films (30 nm) to sustain attachment, spreading, and proliferation of MC3T3‐E1 osteoblasts. Cell area correlated with surface wettability: area was larger on the more hydrophilic surface (TCPS) and lower on the more hydrophobic surface (P3OT). Cells were rounder, characterized by higher circularity values, on TCPS and Si compared to P3OT. P3OT proliferation rate at 24 h fell twofold after 48 h, then recovered at 72 h to a value significantly higher than that on TCPS. Presoaking experiments showed no evidence of cytotoxic effects or leachants from P3OT. Overall, we conclude that P3OT is a viable substrate for osteoblast attachment and proliferation.

     

Diffusion in heterogeneous lattices

We present here the results of our investigations of particle diffusion over different heterogeneous lattices with deep and shallow adsorption sites. A general analytical expression for chemical diffusion coefficient has been derived for a number of inhomogeneous lattices of different dimensionality and symmetry. We have calculated coverage dependencies of diffusion coefficients. The analytical data have been compared with the numerical data obtained by the kinetic Monte Carlo simulations. Almost perfect agreement between the respective results has been found.     

SR电机在转子位置检测中的应用

连续变速驱动的最新设计能够提高产品性能和系统效率.可以从数字控制中受益的一类电机是开关磁阻电机.相比其他类型的调速驱动,SR电机以其简单的机械构造,高效率和高功率密度,体现出成本和可靠性优势.本文通过对SR电机的原理分析,利用MC56F8006数字信号控制器和专利算法,实现转子位置的检测.     

基于ZigBee/IEEE 802.15.4的低成本辅助驾驶系统

本文提出一个完整的基于ZigBee的驾驶辅助系统解决方案,该方案充分利用了具有低成本、低功耗和安全无线网络功能等特性的ZigBee协议。     

经济高效的矢量控制驱动(上) 使用单旁路电流传感

本文描述了基于飞思卡尔MC56F8013/23数字信号控制器的三相AC感应电机矢量驱动解决方案.