一种测试不同温度下非饱和土土-水特征曲线的试验装置

研究目的：研制一种试验装置,以实现对非饱和土土-水特征曲线温度效应的有效测试。创新要点：1．研制了一种温控非饱和土三轴试验装置,包括加载系统、吸力控制系统和温度控制系统;2．利用研制的温控非饱和土三轴试验装置,对不同温度（25,40和60℃）以及不同应力（40100和200kPa）条件下的非饱和土土-水特征曲线进行了试验测定。研究方法：1．总结分析已有的温控三轴仪所采用的加热方式的优缺点,提出环向加热压力室内水体的方法;2．基于GDS非饱和土三轴仪,研制可实现温度控制功能的温控非饱和土三轴仪（图1、2）;3．开展不同温度及不同应力条件下非饱和土土水特征曲线的试验研究。重要结论：1．所研制的温控非饱和土三轴仪的实用效果得到验证;2．温度的升高将引起非饱和土持水性能的降低。     

一种基于CDMA的多信道自组网MAC协议

This paper proposes a novel multichannel medium access control(MAC)protocol based on CDMA that improves network performance and reduces collision probability in wireless ad hoc networks.In the scheme,the code channel is divided into common channel,broadcast channel and several data channels.Simulation results show that the proposed protocol can achieve significantly better performance than the IEEE 802.11 standard.     

Implementation of a new PC based controller for a PUMA robot

This paper describes the replacement of a controller for a programmable universal machine for assembly (PUMA) 512 robot with a newly designed PC based (open architecture) controller employing a real-time direct control of six joints. The original structure of the PUMA robot is retained. The hardware of the new controller includes such in-house designed parts as pulse width modulation (PWM) amplifiers, digital and analog controllers, I/O cards, signal conditioner cards, and 16-bit A/D and D/A boards. An Intel Pentium IV industrial computer is used as the central controller. The control software is implemented using VC programming language. The trajectory tracking performance of all six joints is tested at varying velocities. Experimental results show that it is feasible to implement the suggested open architecture platform for PUMA 500 series robots through the software routines running on a PC. By assembling controller from off-the-shell hardware and software components, the benefits of reduced and improved robustness have been realized.     

Science Letters:A power divider based on a new kind of composite right/left-handed transmission line (CRLH TL) unit

INTRODUCTION Wave propagation in a material with negative magnetic permeability and negative electric permit- tivity was first theoretically analyzed by Veselago (1968). In such a left-handed material (LHM), the electric field E, the magnetic field H and the wave vector k of electromagnetic wave propagation obey the left-hand rule (instead of the right-hand rule for usual materials). After Smith et al.(2000) demon- strated simultaneously negative permeability and permittivity, using cop…     

基于非对称逆布局表示的图像周长计算方法

The non-symmetry anti-packing image representation （NAIR） uses a sequence of the instances of some predefined prototypes to represent an image. While significantly reducing the instances required to represent an image in contrary to the quadtree and the linear quadtree, however, NAIR has lost the explicit space relationship among these instances and hence made some geometric operations such as perimeter computation hard to be implemented. In this paper, longitude and latitude grid （L^2G）, a data structure which can restore lost space relationship from the NAIR is first presented, and then a novel algorithm to compute the perimeters of the images represented by the NAIR is presented. The experimental results show that the new algorithm has saved at least 90% of the running time comparing with that based on the quadtree.     

基于时域模型的路面平整度模拟

为了更加直观有效地描述路面平整度,提出了一种路面平整度的模拟方法,即随机正弦波法.该方法将路面平整度表示成大量具有随机相位的正弦或余弦之和,采用离散谱逼近目标随机过程,是一种离散化数值模拟路面平整度的方法.根据给定的路面功率谱系数,在时域路面随机位移输入的频率特征与给定的路面谱相一致的情况下,通过计算机模拟将路面平整度优化成为随机振动的等效信号,得到各等级下路面的平整度曲线.结果表明：随机正弦波法适用于实测道路谱的时域模拟,由于该方法数学推导严密,使用范围广泛,且模拟曲线直观,对于汽车平顺性研究具有十分重要的意义.最后,提出一个与路面功率谱系数相关的平整度指标——名义平整度指数.     

定价多资产美式期权的半线性Black-Scholes偏微分方程的唯一解

In this paper, by using the optimal stopping theory, the semilinear Black-Scholes partial differential equation （PDE） was invesigated in a fixed domain for valuing two assets of American （call-max/put-min） options. From the viscosity solution of a PDE, a unique viscosity solution was obtained for the semilinear Black-Scholes PDE.     

A maximum power point tracker for photovoltaic energy systems based on fuzzy neural networks

To extract the maximum power from a photovoltaic （PV） energy system, the real-time maximum power point （MPP） of the PV array must be tracked closely. The non-linear and time-variant characteristics of the PV array and the non-linear and non-minimum phase characteristics of a boost converter make it difficult to track the MPP for traditional control strategies. We propose a fuzzy neural network controller （FNNC）, which combines the reasoning capability of fuzzy logical systems and the learning capability of neural networks, to track the MPP. With a derived learning algorithm, the parameters of the FNNC are updated adaptively. A gradient estimator based on a radial basis function neural network is developed to provide the reference information to the FNNC. Simulation results show that the proposed control algorithm provides much better tracking performance compared with the filzzy logic control algorithm.     

A new neural network model for the feedback stabilization of nonlinear systems

A new neural network model termed ＇standard neural network model＇ （SNNM） is presented, and a state-feedback control law is then designed for the SNNM to stabilize the closed-loop system. The control design constraints are shown to be a set of linear matrix inequalities （LMIs）, which can be easily solved by the MATLAB LMI Control Toolbox to determine the control law. Most recurrent neural networks （including the chaotic neural network） and nonlinear systems modeled by neural networks or Takagi and Sugeno （T-S） fuzzy models can be transformed into the SNNMs to be stabilization controllers synthesized in the framework of a unified SNNM. Finally, three numerical examples are provided to illustrate the design developed in this paper.     

基于微阵列技术的缺氧/复氧诱导下血管内皮细胞转录组分析

目的:应用全转录组芯片研究缺氧/复氧诱导下人脐静脉内皮细胞(HUVEC)的转录组轮廓。创新点:血管内皮细胞(VEC)缺氧/复氧损伤被视定为许多生理和病理过程中导致器官功能障碍的重要驱动因素。然而,其详细病理生理机制和基因表达谱信息尚未阐明。本研究首次应用全转录组芯片技术研究VEC缺氧/复氧诱导下的转录组轮廓。方法:采用缺氧孵育3h后复氧1h的HUVEC为缺氧/复氧组,同时常氧孵育的HUVEC为常氧对照组。应用含58 339条探针的全转录组芯片检测每组三个样本。对差异表达基因进行生信分析和功能验证。结论:本研究发现372个有意义的差异表达基因探针。相关基因涵盖多种途径和功能,例如氧自由基的产生、钙超载、炎症、糖脂代谢、内皮细胞增殖、分化、细胞骨架及通透性调节、细胞裂解、凋亡和血管生成。另外,实验进一步表明,差异表达基因pleckstrin同源样域家族A成员1(PHLDA1)的m RNA和蛋白质表达结果与微阵列结果一致。STRING分析发现,PHLDA1可能与差异表达基因SLC38A3、SLC5A5、Lnc-SLC36A4-1和Lnc-PLEKHJ1-1具有物理性和/或功能性相互作用,这有望揭示VEC在缺氧/复氧环境下长链非编码RNA(lnc RNA)的相关机制。     

基于虚拟现实的数据结构三维动态教学系统

针对传统板书式教学和组态式教学软件在直观性和趣味性方面的不足,设计并实现了一种基于虚拟现实技术的数据结构三维动态教学系统。系统以VC/MFC+OpenGL的混合软件开发方式实现,具备简单、直观、易用并且交互性良好的特点,还利用Windows多线程技术实现了算法演示步骤与代码当前执行行的同步关联运行。课堂教学应用表明,达到了改进数据结构课程教学、提高学生学习该课程积极性的目的。     

基于毒品层析试条定量测试仪的研究

阐述了MOR层析试条测试仪的基本结构、工作原理以及光电传感器的设计。实验表明，用该仪器对免疫层析试夺进行定量检测是可能的。     

基于一个新核函数的半定规划的内点算法的复杂性分析

Interior-point methods （IPMs） for linear optimization （LO） and semidefinite optimization （SDO） have become a hot area in mathematical programming in the last decades. In this paper, a new kernel function with simple algebraic expression is proposed. Based on this kernel function, a primal-dual interior-point methods （IPMs） for semidefinite optimization （SDO） is designed. And the iteration complexity of the algorithm as O（n^3/4 log n/ε） with large-updates is established. The resulting bound is better than the classical kernel function, with its iteration complexity O（n log n/ε） in large-updates case.     

一种基于凹凸特性的脱机英文字母识别方法

提出了一种基于整体（凹凸）特性的脱机大写体英文字母识别方法。首先计算字母图像的赋值背景,再从中提取凹凸特性,然后根据凹凸特性构建分类表进行分类识别。     

面向一流人才培养的研究生教育质量评价方法初探--基于层次分析与模糊综合评判的指标体系研究

研究生教育在"双一流"建设中具有高端引领和战略支撑作用。要提升研究生教育质量,必须加强研究生培养质量保障体系建设,而构建研究生教育质量评价体系是其重要一环。为此,本文提出研究生教育质量评价的基本原则和价值取向,并据此研究设计涵盖学生发展、师资队伍、学校条件以及利益相关方满意度等4项一级指标、13项二级指标和91项三级指标的研究生教育质量综合评价方案。在此基础上,运用专家调查法对91项三级指标重要度进行0~5级综合评价,采用层次分析法对三级指标的权重进行科学赋权。同时,采用模糊综合评价方法对13项二级指标与4项一级指标进行权重分析与判断,进而给出一套完整的研究生教育质量综合评价指标体系,为科学评价面向一流人才培养的研究生教育质量提供参考和借鉴。     

Incremental min-period retiming algorithm for FPGA synthesis based on influence of fan-outs

An improved linear-time retiming algorithm is proposed to incrementally optimize the clock period,especially considering the influence of the in-out degree of the critical combinational elements.Firstly,the critical elements are selected from all the critical combinational elements to retime.Secondly,for the nodes that cannot be performed with such retiming,register sharing is implemented while the path delay is kept unchanged.The incremental algorithm can be applied with the technology mapping to minimize the critical path delay and obtain fewer registers in the retimed circuit with the near-optimal clock period.Compared with Singh’s incremental algorithm,experiments show that the proposed algorithm can reduce the flip-flop count by 11% and look-up table(LUT) count by 5% while improving the minimum clock period by 6%.The runtime is also reduced by 9% of the design flow.     

Research on new software compensation method of static and quasi-static errors for precision motion controller

To reduce mechanical vibrations induced by big errors compensation, a new software compensation method based on an improved digital differential analyzer （DDA） interpolator for static and quasi-static errors of machine tools is proposed. Based on principle of traditional DDA interpolator, a DDA interpolator is divided into command generator and command analyzer. There are three types of errors, considering the difference of positions between compensation points and interpolation segments. According to the classification, errors are distributed evenly in data processing and compensated to certain interpolation segments in machining. On-line implementation results show that the proposed approach greatly improves positioning accuracy of computer numerical control （CNC） machine tools.     

PMAC罗茨鼓风机扭叶转子加工数控系统研究

为实现罗茨鼓风机扭叶转子的专用数控加工,根据三叶扭叶转子的曲面特征,设计了一种新颖的数控铣削的方法,研制了基于PMAC的罗茨鼓风机扭叶转子加工试验台专用数控系统。系统上层控制软件采用模块化设计,并利用V isual Basic6.0开发了相应的人机界面和管理应用功能模块。调试的结果表明,系统软件运行稳定,实现了对了扭叶转子的铣削数控加工。     

重复代码自动检测工具的研究与设计

重复代码是程序中最常见的代码“坏味道”.在改进的Kontogiannis度量方法及基于过程蓝图的参数化匹配检测方法基础上,提出以过程蓝图为基础,设计出一个重复代码自动探测工具,并给出实现系统结构.同时论述了工具种各模块的设计与实现方法,着重讨论了重复代码检测器及存储结构的设计。     

基于MATLAB和BP网络的公路软基沉降量预测模型

人工神经网络具有强大的非线性映射能力,文章利用BP神经网络建立了公路软土地基沉降量预测模型,并用MATLAB人工神经网络工具箱进行了实现。根据实测资料,对此预测模型进行训练和预测,试验表明,预测模型具有较好的预测精度,操作简单,具有广阔的工程应用前景。