基于饱依丁-汤姆逊模型的软岩损伤蠕变模型

为更加准确地描述深部软岩的蠕变全过程,以饱依丁-汤姆逊模型为基础,将损伤变量引入到蠕变方程中,并构造了可描述加速蠕变阶段的模型元件,通过串联得到了新的蠕变模型。结果表明:该模型能够较好地描述软岩的衰减蠕变、稳态蠕变、加速蠕变阶段。用该模型对泥质页岩的蠕变试验结果进行数据拟合对比,结果显示该模型的拟合曲线与实验曲线基本吻合,拟合度为0.99733,能够很好地反映出软岩蠕变的特性,适合用于描述深部软岩的蠕变行为。     

基于FPGA的SDRAM的控制器实现与性能分析

高速数据采集在通信、雷达、引信编程监测和视频图像处理等系统中具有广泛的应用,系统中大量使用SDRAM实现数据缓存。SDRAM以其体积小、容量大、读写速度快、成本低等特点被广泛应用于工业电子设备中。本文在介绍SDRAM工作原理的基础上,提出了一种基于FPGA控制SDRAM控制器的方法,这种控制器以FPGA为基础,将较难控制的SDRAM转化为用硬件描述语言编写其控制器,从而将复杂问题简单化,进而利用Verilog语言在Quartus9.1的开发环境中进行了设计输入与仿真验证,证明系统的正确性并分析SDRAM如何达到最优性能。     

基于伪随机序列的聚合物光纤微弱光信号检测

提出了一种利用FPGA发出的伪随机序列检测微弱光信号的方法。用伪随机序列调制LED或LD光源,注入测量光纤,输出光信号经过光电转换后与伪随机序列的调制信号做相关检测。由于伪随机序列具有与白噪声相近的相关特性,测量过程中的干扰、噪声对相关峰值影响很小。因此,可以检测到微弱的输出光信号,提高了测量精度。测量系统由LabVIEW虚拟仪器实现。     

通用编程器可变频率的实现

通用编程器是每个单片机应用开发工作者必不可少的开发工具,其工作原理是先保证目标MCU进入监控状态,然后实现擦除及编程。而在保证目标MCU进入监控状态的硬件条件中,很重要的一项是需要给目标MCU提供一定频率的时钟信号。     

电机设备运行参数远程监控系统设计

本文根据电动机的运行特点,采集电动机的电压、电流、转速和温度四个基本参数,用以观察电动机是否在正常工作状态中,如果出现工作异常,可以及时发现,并及时处理。该系统将电参数检测采集、无线网络技术、工业现场总线技术,以及计算机用户软件有机的结合,实现了对电机远行状态的远程实时监测、控制与管理,使整个系统实现了智能化、网络化、系统化的管理,解决了多地点分布的电机系统无法实现实时控制和系统管理的技术问题。     

Highly conductive and transparent carbon nanotube-based electrodes for ultrathin and stretchable organic solar cells

In this work, we have presented a freestanding and flexible CNT-based film with sheet resistance of 60 ?/ and transmittance of 82% treated by nitric acid and chloroauric acid in sequence. Based on modified CNT film as a transparent electrode, we have demonstrated an ultrathin, flexible organic solar cell(OSC) fabricated on 2.5-μm PET substrate. The efficiency of OSC, combined with a composite film of poly(3-hexylthiophene)(P3HT) and phenyl-C61 butyric acid methyl ester(PCBM) as an active layer and with a thin layer of methanol soluble biuret inserted between the photoactive layer and the cathode, can be up to 2.74% which is approximate to that of the reference solar cell fabricated with ITO-coated glass(2.93%). Incorporating the as-fabricated ITO-free OSC with pre-stretched elastomer, 50% compressive deformation can apply to the solar cells. The results show that the as-prepared CNT-based hybrid film with outstanding electrical and optical properties could serve as a promising transparent electrode for low cost, flexible and stretchable OSCs, which will broaden the applications of OSC and generate more solar power than it now does.     

气相色谱–质谱法测定速溶咖啡中糠醛和5-羟甲基糠醛

建立测定速溶咖啡中糠醛和5-羟甲基糠醛的气相色谱–质谱法。样品经乙腈提取,100 mg C18、50 mg强阳离子交换剂（SCX）、150 mg无水MgSO4净化,经HP-INNOWAX毛细管柱分离,选择离子扫描（SIM）模式,同位素内标法定量。糠醛、5-羟甲基糠醛的质量浓度在0.001～8.0μg/mL范围内线性关系良好,相关系数大于0.999,方法检出限为0.080～0.083 mg/kg,平均回收率为91.8%～96.8%,相对标准偏差为2.8%～6.5%(n=5)。该方法简单快速、灵敏可靠,为速溶咖啡中糠醛、5-羟甲基糠醛的提取和检测提供了可靠的技术支撑。     

嵌入式应用开发中通用串行通信程序的设计方法

分析了嵌入式开发中不同MCU串行通信编程的共性,根据软件工程的基本原理提取了MCU串行通信编程的基本要素,把编程要素分为通用部分和个性部分。对于通用部分,给出了能够适用于各种MCU的串行通信程序,对于个性部分,给出了基本编程原理与移植要点。给出的设计方法和程序,分别在8位、16位、32位MCU上进行了测试,可以成为嵌入式开发中的一个通用部件。     

Performance improvement of continuous carbon nanotube fibers by acid treatment

Continuous CNT fibers have been directly fabricated in a speed of 50 m/h-400 m/h,based on an improved chemical vapor deposition method.As-prepared fibers are further post-treated by acid.According to the SEM images and Raman spectra,the acid treatment results in the compaction and surface modification of the CNTs in fibers,which are beneficial for the electron and load transfer.Compared to the HNO3 treatment,HClSO_3 or H_2SO_4 treatment is more effective for the improvement of the fibers' properties.After HCISO_3 treatment for 2 h,the fibers' strength and electrical conductivity reach up to-2 GPa and-4.3 MS/m,which are promoted by-200%and almost one order of magnitude than those without acid treatment,respectively.The load-bearing status of the CNT fibers are analyzed based on the downshifts of the G' band and the strain transfer factor of the fibers under tension.The results reveal that acid treatment could greatly enhance the load transfer and inter-bundle strength.With the HCISO3 treatment,the strain transfer factor is enhanced from-3.9%to-53.6%.     

Detection of invisible phonon modes in individual defect-free carbon nanotubes by gradient-field Raman scattering

We provide an effective method to investigate the field gradient effect in nanoconfined plasmon-matter interaction.Aligned ultralong SWNTs without defects were grown on marked substrates, followed by assembling gold nanoparticle clusters around individual nanotubes. The Raman scattering behavior of a nanotube placed in an atomic scale nanogap between adjacent nanoparticles was studied. In addition to the expected plasmon-induced Raman enhancement up to 103,the defect-free D-mode of an individual SWNT induced by gradient field is found for the first time. When the light is confined at atomic scale, gradient field Raman scattering becomes significant and dipole-forbidden phonon modes can be activated by quadrupole Raman tensor variation, indicating breakdown of the Raman selection rules.