一种低成本线阵CCD驱动与数据采集处理系统的研究

探索了一种在低成本下实现线阵CCD输出信号快速采集以及与PC通信的方法。讨论了线阵CCD系统的整体结构及工作流程。采用VHDL语言编写了驱动程序,实现了CCD的正确工作。利用DSP实现了对下位CCD的控制,在控制程序中利用"乒乓原理"实现了线阵CCD的数据采集,并同时给PC快速上传数据。基于Visual C++6.0平台编写了PC机控制软件,实现了对硬件电路的控制和对CCD输出信号的分析处理。     

干涉型光纤水听器调制光源的一种实现方法

直接调制光源(多量子阱激光器)的相位载波零差检测方式，在干涉型光纤水听器的信号检测技术中具有明显的优越性。详细描述了采用高频正弦波，对多量子阱分布反馈激光器进行直接驱动调制的一种实现方法。实验表明达到了水听器对光源高频稳定的要求。该调制技术也可应用于光纤通信等领域。     

大功率LED脉冲位置调制解调设计

脉冲位置调制是室内可见光通信的主要调制方式之一,它具有功率利用率高,频带利用率好,抗干扰性强的特点.为实现室内大功率白光LED照明通信,在分析PPM的原理基础上提出了一种改进的调制方式,给出了这种PPM符号的结构,并设计了大功率LED的驱动电路.其主要特点是由单片机直接输出帧同步信号加PPM信号,不设置保护时隙,其利用...     

基于遥感影像的嘉兴市城市扩张与驱动力分析

在当前高速城市化的背景下,为及时了解嘉兴市的城市发展现状,使用遥感手段提取各时间段内城市的建设区域,并分析了扩张过程的时空特征,再结合社会经济数据探究了城市扩张的驱动力因素.结果表明：嘉兴市在1993~2013年间城市扩张明显,扩张速度和强度先增后减,扩张方向由西北转向南,扩张模式经历了“主动型-被动型-稳定型”的转变过程,扩张合理性较差,城市扩张速率高于人口增长速率,扩张驱动因子主要为经济发展、产业结构调整和人口增长.     

Pitch-Based Laminated Carbon Formed by Pressure Driving at Low Temperature as High-Capacity Anodes for Lithium Energy Storage Systems

Pitch has been used to prepare electrodes by high-temperature heat treatments for supercapacitors, lithium-ion batteries, on account of its rich aromatic ring structure. Here, the toluene-soluble component of pitch is used to prepare a kind of laminated carbon. This was realized by a template-free synthesis at low temperature with the addition of pressure. The toluene-soluble component has a small molecular weight, which makes the thermal deformation ability stronger and then enhances the orientation of the carbon layer with the help of pressure. The prepared anode exhibits a splendid electrochemical performance compared with the traditional graphite anode. A high stable capacity of approximately 550 mAh g⁻¹ at 50 mA g⁻¹, which is much higher than graphite (372 mAh g⁻¹), is obtained. Also, when the current density is up to 2 A g⁻¹, the capacity is about 150 mAh g⁻¹. Surprisingly, it also delivers a superior cycling performance. And when used as the anode/cathode electrode for lithium-ion capacitors, a high energy density can be obtained. The present work offers an opportunity to utilize the pitch source in lithium energy storage with promising cycle life, high energy/power density, and low cost.     

Perfect Optical Nonreciprocity with Mechanical Driving in a Three-Mode Optomechanical System *

Nonreciprocal devices are indispensable for building quantum networks and ubiquitous in modern communication technology. Here, we study perfect optical nonreciprocity in a three-mode optomechanical system with mechanical driving.The scheme relies on the interference between optomechanical interaction and mechanical driving. We find perfect optical nonreciprocity can be achieved even though nonreciprocal phase difference is zero if we drive the system by a mechanical driving with a nonzero phase. We obtain the essential conditions for perfectoptical nonreciprocity and analyze properties of the optical nonreciprocal transmission. These results can be used to control optical transmission in quantum information processing.      

离心力场下H2O和R12热驱动换热特性实验研究

本文实验研究了离心力场下细微封闭循环通道中,以H2O和氟利昂R12为热驱动介质的热驱动流动规律和换热特性,重点分析了热驱动换热效果随Ra数Ro数的变化规律以及冷却效果。实验结果表明:在热流密度和旋转速度相同的条件下,采用介质R12可以获得较高的平均换热系数,冷却效果也优于以H2O为介质的冷却效果。最后建立了两种介质条件下相应的准则关系式。     

Mass spectrometric approaches in impaired driving toxicology

Driving under the influence of prescribed or illegal drugs increases the risk of having road accidents, just like driving under the influence of alcohol. In forensic toxicology, an increasing number of blood samples must be analyzed for drugs. Immunoassays tailored for a limited number of drugs (of abuse) are usually applied as prescreening tests at the roadside and/or in the laboratory. However, many other common drugs, such as anesthetics, antidepressants, antiepileptics, antihistamines, newer designer drugs, herbal drugs, neuroleptics (antipsychotics), opioids, or sedative-hypnotics, can also impair drivers. Therefore, this paper reviews multianalyte single-stage and tandem gas or liquid chromatography–mass spectrometry (GC-MS or LC-MS) procedures for the screening, identification, and validated quantification of such drugs in blood that have been reported since 2003. Basic information about the biosample assayed, workup, chromatography, the mass spectral detection mode, and validation data is summarized in tables. The pros and cons of the reviewed procedures are critically discussed, particularly with respect to their probable usefulness in impaired driving toxicology. Parts of this review were presented as a plenary lecture at T2007, the joint meeting of the International Council on Alcohol, Drugs, and Traffic Safety (ICADTS) and The International Association of Forensic Toxicologists (TIAFT), Seattle (WA), August 26–30, 2007.     

In Situ Synchrotron X-ray Diffraction Studies of Hydrogen-Desorption Properties of 2LiBH4–Mg2FeH6 Composite

Adding a secondary complex metal hydride can either kinetically or thermodynamically facilitate dehydrogenation reactions. Adding Mg₂FeH₆ to LiBH₄ is energetically favoured, since FeB and MgB₂ are formed as stable intermediate compounds during dehydrogenation reactions. Such “hydride destabilisation” enhances H₂-release thermodynamics from H₂-storage materials. Samples of the LiBH₄ and Mg₂FeH₆ with a 2:1 molar ratio were mixed and decomposed under three different conditions (dynamic decomposition under vacuum, dynamic decomposition under a hydrogen atmosphere, and isothermal decomposition). In situ synchrotron X-ray diffraction results revealed the influence of decomposition conditions on the selected reaction path. Dynamic decomposition of Mg₂FeH₆–LiBH₄ under vacuum, or isothermal decomposition at low temperatures, was found to induce pure decomposition of LiBH₄, whilst mixed decomposition of LiBH₄ + Mg and formation of MgB₂ were achieved via high-temperature isothermal dehydrogenation.