输电线路杆塔纵向不平衡载荷动态预测模型研究

为了提高输电线路杆塔纵向不平衡载荷控制性能和抗波动冲击能力,提出一种基于耦合波动抑制和机构运动力学分析的输电线路杆塔纵向不平衡载荷预测模型,构建输电线路杆塔的耦合波动载荷测量模型,采用传感器进行输电线路杆塔的力学参数采集,构建输电线路杆塔纵向不平衡耦合动力学模型,运用封闭矢量法建立输电线路杆塔的纵向波动力学控制模型,采用二自由度离散控制方法进行输电线路杆塔的欠驱动机构模型设计,采用双连杆柔性空间力学分配方法,实现输电线路杆塔纵向不平衡载荷动态预测和未知载荷的质量参数辨识,结合相关性耦合波动控制方法,获得载荷的质量参数,实现输电线路杆塔的运动力学分析和动态载荷预测。仿真结果表明,采用该方法进行输电线路杆塔纵向不平衡载荷动态预测的准确性较高,可靠性较好,动态收敛性较强。     

架空输电线路杆塔结构可靠监测平台设计

完全依赖底层网络对称性设置中继节点，容易导致监测平台网络时延较高，对此设计了架空输电线路杆塔结构可靠监测平台。平台有杆塔监测器和电源模块，运用有限元模型进行力学模拟，建立架空输电线路塔—线体系。根据杆塔结构可靠性影响因素，融合WSN与RFID技术，搭建杆塔结构监测网络。考虑网络不对称条件，结合杆塔结构监测数据的传输线路，设计以传输延时为基础的中继节点布置优化方法，运用蒙特卡罗法计算杆塔结构实际失效概率，反映杆塔结构可靠程度。平台应用结果表明，所提监测平台运行过程中，平均网络时延约为285 ms,很好地满足了杆塔结构可靠监测的实时性要求。     

特高压酒杯塔组立对结构影响的仿真分析

在输电线路的铁塔受力强度问题的研究中,为了克服施工经验和理论研究的不足,以1000kV晋东南-南阳-荆门特高压交流试验示范工程酒杯塔为例,针对施工载荷对杆塔结构受力的影响,应用数值仿真方法对塔片起吊瞬间的受力、大质量中横担吊装以及边横担吊装等施工工艺进行有限元仿真分析.研究结果表明,塔片吊装瞬间需要补强、中横担宜前后分片吊装、边横担可以利用地线支架吊装,并提出局部补强的建议.输电杆塔组立施工的仿真分析弥补了施工经验的不足,仿真研究结果为施工提供了科学依据.     

基于嵌入式linux的杆塔倾斜度在线监测仪设计

为保障电网的安全稳定运行,减少因杆塔倾斜引起的停电事故,需要对杆塔的状态进行实时监测。设计开发了一种杆塔倾斜度在线监测装置。建立了杆塔倾斜度监测模型,根据重力加速度测量值计算倾斜角的原理,采用SCA100T-D01双轴倾角传感器进行数据采集,采用基于arm9的嵌入式linux系统进行数据的存储和计算,并通过以太网或GPRS网络传送数据,实现了对杆塔倾斜各状态量的在线监测。详述了该装置各个模块的软件设计。该装置支持配置不同地区的重力加速度,提高了测量精度;支持自动配置初始安装角度,大大提高了输电线路生产管理水平。详述了自动配置的规范,经工程实践,该装置在输电线路杆塔倾斜度的监测上取得了良好应用。     

浅析10kV耐张杆塔中心桩位移的设计与计算

通常对于耐张杆塔结构进行设计,为确保在挂线以后导线对杆塔的电气安全的距离,要考虑多种因素包括横担宽度、长短横担、中相导线挂线点偏移等。中心桩位移的设计与计算就是为了降低这些因素对线路安全运行的危害。     

论用弧垂应力表确定杆塔的最佳呼称高

选择合理的杆塔高度，是输电线路节约投资的措施之一，导线弧垂是和档距的大小有关的，又和应力有关，应力越大，弧垂越小，则杆塔就能放大档距，减少杆塔和绝缘子及金具数量，减少运行和施工的工作量，达到节能减排的目的。     

3D可视化输电线路中杆塔空间挂点计算

将3D可视化技术应用于输电线路管理是当前电力信息化的发展方向.地球是一个不规则椭球体,很难计算出杆塔挂点在地球空间的坐标,因此无法真实、准确地表达线路与杆塔挂点的连接情况.为此,结合大量分析和研究,提出了一种基于Google Earth的杆塔空间挂点计算方法,并应用于所开发的输电线路管理系统中.实践表明,该方法具有计算简单、空间定位精度高、线路与挂点连接逼真等特点,能够满足现有应用的要求.     

贵州省近60年气温变化特征分析及对输电线路运维的影响

为探讨贵州省进60年气温空间变化特征对输电线路的影响,本文采用普通克里格法与协同克里格法两种插值方法的误差进行对比分析,选择协同克里格法对贵州省19个地面观测站1951-2010年的温度观测数据进行空间插值,从而得出贵州省气温分布特征。研究结果表明：贵州省近60年平均温度从1951年的15.2℃上升到了2010年的15.9℃,上升了0.7℃,平均每10年约上升0.12℃;通过气温空间分布特征分析得出在铜仁、榕江、罗甸、望谟一代温度较高,有可能造成输电线路软化而形成弧垂,使输电线路绝缘老化,设计施工时应尽量考虑输电导线绝缘材料的耐热性;习水、毕节、威宁一代,冬季气温较低,有可能造成输电线路覆冰致使线路损坏和杆塔受力过大而倒塌,设计施工时应考虑杆塔承受能力和导线的拉伸能力。     

三维可视化输电线路中杆塔空间挂点计算

将三维可视化技术应用于输电线路管理是当前电力信息化的发展方向。地球是一个不规则椭球体,因此很难计算出杆塔挂点在地球空间的坐标,进而无法真实、准确的表达线路与杆塔挂点的连接情况。为此,本文在结合大量分析和研究的基础上,提出了一种基于Google Earth的杆塔空间挂点计算方法,并应用于所开发的输电线路管理系统中。实践表明,该方法具有计算简单、空间定位精度高、线路与挂点连接逼真等特点,能够满足现有应用的要求。     

特高压交流输变电工程钢管塔组立阶段监理管控关键措施

本文依托皖电东送淮南至上海特高压交流输电示范工程,对线路工程监理工作进行总结,结合特高压钢管塔组立实际特点,探索钢管塔组立施工过程中监理管控的方法和手段,总结钢管塔组立阶段监理管控经验,分析总结监理管控关键环节和重要管控措施。     

Zn_mCd_(l-m)_Sno_3的合成、结构及气敏性质研究

本文探讨了Zn_mCd_(1-m)SnO_3的合成条件,以及固相反应产物物相与组分相对量、反应温度的关系.结果表明:当m=0.5,0.7.0.9时,所出现的产物为非常稳定的钙钛矿型Zn_xCd_(1-x)SnO_3复合氧化物;但当m=0.1,0.3时,除生成Zn_xCd_(1-x)SnO_3外,还出现一个未知物相.研究结果证实了Zn_mCd_(1-x)SnO_3均表现出气敏效应(特别是m=0.5).Zn_(0.7)Cd_(o.3)SnO_3,Zn_(0.3)Cd_(0.7)SnO_3,分别是性能较好的C_2H_5OH及C_2H_2敏材料.     

氧化物电极在氧化锆氧传感器上的应用

用三电极法测量了La1-xSrxMO3 (M :Co ,Mn ,Fe) /ZrO2 电极系统在 40 0～ 80 0℃温度范围内的极化曲线 ,用数学模拟方法从中分离出电化学过电位 ,发现La0 .5Sr0 .5CoO3 的电极阴、阳极特性相近 ,而La0 .5Sr0 .5MnO3 作阴极时的活性高于阳极 ,并且La0 .5Sr0 .5MnO3 阴极已成功应用于工作温度低于 80 0℃下的ZrO2 电压型氧传感器中。     

Remote estimation of chl-a concentration in turbid productive waters — Return to a simple two-band NIR-red model?

Today the water quality of many inland and coastal waters is compromised by cultural eutrophication in consequence of increased human agricultural and industrial activities. Remote sensing is widely applied to monitor the trophic state of these waters. This study investigates the performance of near infrared-red models for the remote estimation of chlorophyll-a concentrations in turbid productive waters and evaluates several near infrared-red models developed within the last 34 years. Three models were calibrated for a dataset with chlorophyll-a concentrations from 0 to 100 mg m⁻³ and validated for independent and statistically different datasets with chlorophyll-a concentrations from 0 to 100 mg m⁻³ and 0 to 25 mg m⁻³ for the spectral bands of the MEdium Resolution Imaging Spectrometer (MERIS) and MODerate resolution Imaging Spectroradiometer (MODIS). The MERIS two-band model estimated chlorophyll-a concentrations slightly more accurately than the more complex models, with mean absolute errors of 2.3 mg m⁻³ for chlorophyll-a concentrations from 0 to 100 mg m⁻³ and 1.2 mg m⁻³ for chlorophyll-a concentrations from 0 to 25 mg m⁻³. Comparable results from several near infrared-red models with different levels of complexity, calibrated for inland and coastal waters around the world, indicate a high potential for the development of a simple universally applicable near infrared-red algorithm.     

On the Expressive Power of Polyadic Synchronisation in π-calculus

We extend the π-calculus with polyadic synchronisation, a generalisation of the communication mechanism which allows channel names to be composite. We show that this operator embeds nicely in the theory of π-calculus, and makes it possible to derive divergence-free encodings of distributed calculi. We give a separation result between the π-calculus with polyadic synchronisation (^eπ) and the original calculus, in the style of an analogous result given by Palamidessi for mixed choice. We encode Local Area π showing how to control the local use of resources in ^eπ.     

Magnetically actuated micromechanical tweezers

Two planar actuators with magnetic thin films are used for magnetic tweezers. The planar actuators consisting of a pair of a 75 × 0.8 × 0.3 μm³ silicon oxide beam and a 72 × 13 × 0.3 μm³ silicon oxide plate deposited with a 65 × 4 × 0.1 μm³ Ni magnetic thin film are successfully fabricated and successfully gripped to a single NPC-tw01 cell consisting of Fe₃O₄ magnetic nanoparticles under a vertical magnetic field. The planar actuator bends under an external magnetic field because of the high shape magnetic anisotropy of the Ni magnetic thin film and a highly sensitive microcantilever. NPC-tw01 cells, which are adherent cells, are cultivated in a culture solution. The two planar actuators are placed in water to move and grip a living cell.     

Determination of 3-nitrotyrosine in human urine samples by surface plasmon resonance immunoassay

This paper describes the detection of a low-molecular weight molecule, 3-nitrotyrosine (3-NT) (∼226 Da), in human urine by coupling indirect inhibition assay with a surface plasmon resonance (SPR) sensor. 3-NT antibody (anti-3-NT Ab, mouse IgG) was used in this assay. An optimal antibody concentration has been measured at 27.9 μg/mL in order to obtain the best performance of the sensor surface. The lowest detection limit for 3-NT with this method is 4.7 ng/mL (S/N = 3). Sensor reliability was demonstrated by good specificity, intra-assay and inter-assay relative standard deviations <8%, average recovery of 107.68 ± 19.4% and sensor surface (self-assembled monolayer) stability through more than 200 regeneration cycles and 15 days of repeated measurement. This is the first SPR biosensor assay of 3-NT in human urine. The high stability of the SPR sensor surface underlies the potential of the SPR method as a low cost diagnostic tool for clinical detection of 3-NT.     

On discrete lower π-strategies

Two-person zero-sum differential games of survival are investigated. It is assumed that player I, as well as player II, can employ during the course of the game any lower π-strategy [2], π(t_i) being a finite partition of [t₀, ∞). The concept of a discrete lower π-strategy is introduced and it is shown that if player I (II) confines himself to the space of discrete lower π-strategies, being a subset of the space of lower π-strategies, then he will be able to force the same lower (upper) value as if he could employ any lower π-strategy. Since we do not use any deep facts about differential games, the results contained here might be extended to continuous games.     

Hydrothermal synthesis of hollow ZnSnO3 microspheres and sensing properties toward butane

Hollow ZnSnO₃ microspheres were successfully prepared by hydrothermal method at 160 °C for 12 h. The prepared material was characterized by field emission scanning electron microscope (FESEM), transmission electron microscope (TEM) and X-ray diffraction measurements (XRD). The average diameter of the hollow ZnSnO₃ microspheres was in the range of 400-600 nm. Compared with solid ZnSnO₃ microspheres structure, the hollow ZnSnO₃ microspheres showed better response (S) to butane. To 500 ppm butane, the sensor response (S) of the hollow ZnSnO₃ microspheres was 5.79 at the optimum operating temperature of 380 °C, and the response and recovery time were 0.3 s and 0.65 s, respectively. The sensitivities of sensors based on this material were linear with the concentration of butane in the range of 100-1000 ppm.     

Registration of arbitrary multi-view 3D acquisitions

To register 3D meshes representing smooth surfaces we track the 3D digitization system using photogrammetric techniques and calibrations. We present an example by digitizing a 800 mm × 600 mm portion of a car door. To increase the tracking accuracy the 3D scanner is placed in a cubic frame of side 0.5 m covered with 78 targets. The target frame moves in a volume that is approximately 1100 mm × 850 mm × 900 mm, to digitize the area of interest. Using four cameras this target frame is tracked with of an accuracy of 0.03 mm spatially and 0.180 mrad angularly. A registration accuracy between 0.1 mm and 2 mm is reached. This method can be used for the registration of meshes representing featureless surfaces.     

用ARM7微处理器实现LED显示

介绍了嵌入式系统发展的现状.分析了基于ARM7微处理器S3C44B0系统中八段数码LED显示的实现原理,探讨了S3C44B0与LED的硬件接口设计和软件设计,给出了硬件连接图和部分程序代码.并通过实验验证了八段数码管能循环显示0～F字符.