基于PRAM并行模型最大值查找的方法与改进

随着多处理器的出现,并行技术受到了广泛的关注,成为了加速处理问题速度的重要技术.但是使用并行技术在加速计算的同时也带来了对处理器数量需求的急剧提升,并行成本的显著增加.针对这一问题,通过研究基于PRAM （Parallel Random Access Machine）下的3种最大值查找并行算法中的不足,提出了一种比平衡树算法,快速查找法,双对数深度树方法并行成本（cost）更优的基于数据划分方法的最大值查找并行算法.基于数据划分方法的最大值查找算法有效的解决了现有并行方法中处理器工作量分配不均,对处理器需求过大,实现条件苛刻等问题.为此后类似并行算法降低并行成本提供一个方向.     

3D打印成型陶瓷零件坯体及其致密化技术

3D打印技术在陶瓷零件成型方面具有较大应用潜力,被认为是近净尺寸成型高性能复杂结构陶瓷零件的一种新途径。本文比较了陶瓷零件或其坯体的激光选区熔化、薄材叠加制造、熔融沉积造型、光固化、三维打印和激光选区烧结等不同3D打印工艺及其致密化手段的优势和不足,认为较低的相对密度和强度是阻碍3D打印陶瓷零件实现产品应用的主要障碍。本团队近年来采用造粒混合法制备出具有良好流动性的3D打印复合陶瓷粉体,再通过激光选区烧结(SLS)和冷等静压(CIP)技术分别进行坯体成型及均匀致密化处理,制备出了高性能、复杂结构的Al_2O_3致密陶瓷零件。本文回顾了这些工作,并补充介绍了溶解沉淀和溶剂蒸发这两种制备复合陶瓷粉体的新方法,利用SLS/CIP复合工艺进一步制造了ZrO_2、SiC、高白土等其它材质的复杂陶瓷零件,为3D打印陶瓷用于航空航天、医疗、艺术等领域奠定了基础。     

Effect of the stirring rate on physical and electrochemical properties of LiMnPO4 nanoplates prepared in a polyol process

In a polyol approach to make olivine-typed LiMnPO₄ nanoplates, the effect of the stirring rate on physical and electrochemical properties of the obtained sample has been symmetrically investigated for the first time. The as-prepared powders exhibit well crystalline olivine structure as presented by X-ray diffraction analysis. The secondary particles with a size of 2–3 μm are composed of aggregated nanoplates as verified by particle size analysis and field emission scanning electron microscopy measurement. Transmission electron microscopy presents that the nanoplate is about 18 nm thick along a-axis. The discharge capacity of the sample prepared under a stirring rate of 700 rpm reaches 150 mAh g⁻¹ when cycled at 0.05C after a few cycles.     

大型矿山开采供电方案的设计

分析了矿山供电方案设计的技术要求与控制功能要求,根据项目用电负荷的实际,对矿石开采项目的供电方案进行了设计。该设计方案具有设备技术先进,运行可靠性高,预制模块化设计、占地面积小等特点。     

Propagation properties of rectangular Laguerre–Gaussian-correlated Schell-model beams in atmospheric turbulence

Based on the extended Huygens–Fresnel principle and the second-order moments of the Wigner distribution function (WDF), the analytical expressions for the cross-spectral density (CSD) and the propagation factor of a rectangular Laguerre–Gaussian-correlated Schell-model (LGCSM) beam propagating in atmospheric turbulence are derived. The statistical properties, such as the average intensity, the spectral degree of coherence (SDOC) and the propagation factor, of a rectangular LGCSM beam in free space and atmospheric turbulence are comparatively analysed. It is illustrated that a rectangular LGCSM beam exhibits self-splitting and combing properties on propagation in atmospheric turbulence, and the self-splitting properties of such beam are closely related to its beam orders m and n, which is quite different from other self-splitting beams. In addition, the rectangular LGCSM beam has an advantage for reducing the turbulence-induced degradation compared with the conventional partially coherent beams.     

基于光纤陀螺仪的信号补偿

光纤陀螺仪是目前广泛使用的一种惯性仪器, 但在使用过程中仍然会遇到有很多问题. 光纤陀螺仪在使用过程中由于光纤陀螺仪内部元器件构造、材料的使用、以及元器件的精度等因素, 会产生一些误差, 如启动温度、零漂、刻度因子等. 同时在使用的过程中受外界的环境干扰也会使光纤陀螺仪产生误差, 如受外界的振动, 环境温度变化等. 通过分析研究光纤陀螺仪的原理和输出信号, 建立误差补偿模型, 对误差进行补偿分析. 应用分段平均选点法补偿了由于温度变化在信号中产生的线性趋势项, 以及使用平滑滤波算法对光纤陀螺仪输出信号进行     

机床再制造技术框架及产业化策略研究

机床再制造实际上是一种基于废旧机床资源循环利用的机床制造新模式,对于循环再利用我国量大面广的老、旧机床设备资源以及更新提升我国制造业机床整体质量和制造加工能力具有重要意义,并将导致若干新兴产业的形成.在分析国内外机床维改再利用现状及不足的基础上,总结提出机床综合再制造流程,并建立废旧机床再制造技术框架;结合机床再制造新兴产业的发展前景,分析并提出其产业需求、产业主体、产业模式等产业策略.     

FLUID FLOW IN ROTATING HELICAL SQUARE DUCTS

1 .　INTRODUCTIONTherotatinghelicalsquareducthasextensive lyapplicationsinengineeringforenhancingtheratesofheatandmasstransfer ,suchascoolingsystemsforconductorsofelectric generatormo tors ,gasturbines ,separation processes .Becauseoftherotation ,theCoriolisforcecanalsocontrib utetothe generationofsecondaryflow ,whichcomplicatestheflowcharacteristics .To gethighperformanceofthesedevices,itisimportanttofindouttheflowcharacteristicsinrotatinghelicalsquareducts .Duetothecomplexityoftheproble…     

Procedures for Wavelength Calibration and Spectral Response Correction of CCD Array Spectrometers

This work describes a procedure for acquiring a spectrum of an analyte over an extended range of wavelengths and validating the wavelength and intensity assignments. To acquire a spectrum over an extended range of wavelengths with a spectrometer with a charge coupled device (CCD) array detector, it is necessary to acquire many partial spectra, each at a different angular position of the grating, and splice the partial spectra into a single extended spectrum. The splicing procedure exposes instrument dependent artifacts. It is demonstrated that by taking a spectrum of a reference irradiance source and making spectral correction, the artifacts exposed by the splicing are removed from the analyte spectrum. This is because the irradiance reference spectrum contains the same artifacts as the analyte spectrum. The artifacts exposed by the splicing depend on the wavelength of the splice; therefore it is important to measure the irradiance reference spectrum for the same range of wavelengths used to measure the spectrum of the analyte solution. In other words, there is no general spectral correction factor which is applicable to spectra taken for different range of wavelengths. The wavelength calibration is also carried out by splicing many partial spectra from a source like a krypton lamp. However the wavelength assignments are not sensitive to the splicing procedure and the same wavelength calibration can be used for spectra acquired over different extended wavelength ranges. The wavelength calibration checks the validity of the setting of the grating angular position, and the assignment of wavelengths to individual pixels on the CCD array detector. The procedure is illustrated by measuring the spectrum of an orange glass and the spectrum of a suspension of microalgae.     

FPGA在复杂开关逻辑系统中的应用研究

介绍了复杂逻辑系统的共性特征和需求,根据其特点,研究了使用FPGA克服相关问题的途径.讨论了FPGA对于复杂逻辑的设计方法,多时钟系统中FPGA的处理技术,FPGA设计中的抗干扰策略.以针织机械控制系统为目标.基于VHDL程序语言构建了FPGA原理控制系统,根据测试结果对系统进行了总结分析.