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1.
一种测试不同温度下非饱和土土-水特征曲线的试验装置   总被引:2,自引:0,他引:2  
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。  相似文献   

2.
Implementation of a new PC based controller for a PUMA robot   总被引:1,自引:0,他引:1  
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.  相似文献   

3.
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…  相似文献   

4.
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.  相似文献   

5.
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。  相似文献   

6.
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.  相似文献   

7.
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。  相似文献   

8.
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。  相似文献   

9.
一种基于凹凸特性的脱机英文字母识别方法   总被引:1,自引:0,他引:1  
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。  相似文献   

10.
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。  相似文献   

11.
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.  相似文献   

12.
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。  相似文献   

13.
The Hong Kong Observatory (HKO) provides low-level turbulence alerting service for the Hong Kong International Airport (HKIA) through the windshear and turbulence warning system (WTWS). In the WTWS, turbulence intensities along the flight paths of the airport are estimated based upon correlation equations established between the surface anemometer data and the turbulence data from research aircraft before the opening of the airport. The research aircraft data are not available on day-to-day basis. The remote sensing meteorological instruments, such as the Doppler light detection and ranging (LIDAR) and radar, may be used to provide direct measurements of turbulence intensities over the runway corridors. The performances of LIDAR- and radar-based turbulence intensity data are studied in this paper based on actual turbulence intensity measurements made on 423 commercial jets for a typical case of terrain-induced turbulence in association with a typhoon. It turns out that, with the tuning of the relative operating characteristic (ROC) curve between hit rate and false alarm rate, the LIDAR-based turbulence intensity measurement performs better than the anemometer-based estimation of WTWS for turbulence intensity at moderate level or above. On the other hand, the radar-based measurement does not perform as well when compared with WTWS. By combining LIDAR- and radar-based measurements, the performance is slightly better than WTWS, mainly as a result of contribution from LIDAR-based measurement. As a result, the LIDAR-based turbulence intensity measurement could be used to replace anemometer-based estimate for non-rainy weather conditions. Further enhancements of radar-based turbulence intensity measurement in rain would be necessary.  相似文献   

14.
通过采用问卷调查和跟踪访谈的研究方法,对人教版(PEP)SEFC(2003)教材实施以来Integrating skills部分教学问题及其原因进行深入调查发现:高中英语教师对Integrating skills部分读写关系理解存在偏差,读写关系处理失当,读写技能综合教学设计能力欠缺。其主要原因是教师对Integrating skills部分教材的编写意图把握不准;对阅读教学类型选择有误;对读写技能综合教学类型未加区分。  相似文献   

15.
为境外窃取、刺探、收买、非法提供国家秘密、情报罪是指为境外的机构、组织、人员窃取、刺探、收买、非法提供国家秘密、情报行为。该罪是1997年刑法新增的罪名,用于解决1979年刑法制定后日益增多的非间谍人员为境外非间谍机构窃取、刺探、收买、非法提供国家秘密、情报的行为。本罪易于同其他涉及国家秘密的犯罪混淆,本文试图分析本罪与间谍罪的区别。  相似文献   

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