Measurement of a reciprocal four-port transmission line structure using the 16-term error model

A new method to measure reciprocal four-port structures, using a 16-term error model, is presented. The measurement is based on 5 two-port calibration standards connected to two of the ports, while the network analyzer is connected to the two remaining ports. Least-squares-fit data reduction techniques are used to lower error sensitivity. The effect of connectors is deembedded using closed-form equations. (C) 2007 Wiley Periodicals, Inc.

A new structure of In-based ohmic contacts to n-type GaAs

Electrical, structural and reaction characteristics of In-based ohmic contacts to n-GaAs were studied. Attempts were made to form a low-band-gap interfacial phase of InGaAs to reduce the barrier height at the metal/semiconductor junction, thus yielding low-resistance, highly reliable contacts. The contacts were fabricated by e-beam sputtering Ni, NiIn and Ge targets on VPE-grown n(+)-GaAs film (approximate to 1 mu m, 2 x 10(18) cm(-3)) in ultrahigh vacuum as the structure of Ni(200 Angstrom)/NiIn(100 Angstrom)/Ge(40 Angstrom)/n(+)-GaAs/SI-GaAs, followed by rapid thermal annealing at various temperatures (500-900 degrees C). In this structure, a very thin layer of Ge was employed to play the role of heavily doping donors and diffusion limiters between In and the GaAs substrate. Indium was deposited by sputtering NiIn alloy instead of pure In in order to ensure In atoms to be distributed uniformly in the substrate; nickel was chosen to consume the excess indium and form a high-temperature alloy of Ni3In. The lowest specific contact resistivity (rho(c)) of (1.5 +/- 0.5)x 10(-6) cm(2) measured by the Transmission Line Method (TLM) was obtained after annealing at 700 degrees C for 10 s. Auger sputtering depth profile and Transmission Electron Microscopy (TEM) were used to analyze the interfacial microstructure. By correlating the interfacial microstructure to the electronical properties, InxGa1-xAs phases with a large fractional area grown epitaxially on GaAs were found to be essential for reduction of the contact resistance.

一种输电线路巡检机器人控制系统的设计与实现

介绍了一种超高压输电线路巡检机器人控制系统的设计与实现方法.根据巡检作业任务的要求,采用遥控与局部自主相结合的控制模式实现巡检机器人沿线行走及跨越障碍.设计了巡检机器人有限状态机模型,实现了机器人遥控与局部自主控制的有机结合.采用基于激光传感器定位的方法实现了巡检机器人的自主越障控制.实验结果表明,该机器人可实现沿线行走及自主跨越障碍,从而验证了控制系统设计的有效性与合理性.

基于视觉伺服的输电线巡检机器人抓线控制

巡检机器人在越障时,需要完成机器人手臂的准确抓线控制.结合输电线的几何特征和摄像机成像原理,提出了一种基于单摄像机的立体视觉方法来确定输电线的位置和姿态.基于该定位方法及视觉伺服理论,建立机械手抓线伺服控制模型.利用自行研制的巡检机器人进行了视觉伺服抓线实验;实验结果验证了该方法的有效性.

输电线巡检机器人行走动力特性与位姿分析

根据跨越超高压输电线路障碍物的类型,提出一种新的双臂自主越障巡检机器人机构。该机器人采用复合轮爪机构在架空地线上连续行走并跨越障碍。由于架空地线呈悬链线状,机器人在连续行走过程中会出现上坡和下坡,对行走动力特性的影响非常明显。在上坡时行走电动机提供驱动力矩,在下坡时行走电动机提供制动力矩,以保持匀速巡线。详细分析了机器人在架空地线上行走时所处的加速、匀速、减速和停止的各个状态,驱动机器人所需的驱动力矩以及它们与机构参数之间的关系,并应用优化方法给出各个状态电动机驱动力矩最小时,机器人机构参数对应的最优解,为巡检机器人的设计和控制系统方案的确定提供了理论依据。

基于分布式专家系统的超高压输电线路巡检机器人控制系统的研究

探讨了基于分布式专家系统的超高压输电线路巡检机器人控制系统，给出了一种利用CUPS和C、VC++混合编程构成分布式专家系统作为机器人控制器的方法，并且提出了一种基于规则和证据的可信度(CF)的分布式专家系统的协调算法．经过试验论证，该控制方法能很好地实现超高压输电线路巡检机器人的作业功能。

Determination of ionic resistance and optimal composition in the anodic catalyst layers of DMFC using AC impedance

In the present study, a method based on transmission-line mode for a porous electrode was used to measure the ionic resistance of the anode catalyst layer under in situ fuel cell operation condition. The influence of Nafion content and catalyst loading in the anode catalyst layer on the methanol electro-oxidation and direct methanol fuel cell (DMFC) performance based on unsupported Pt-Ru black was investigated by using the AC impedance method. The optimal Nafion content was found to be 15 wt% at 75 degrees C. The optimal Pt-Ru loading is related to the operating temperature, for example, about 2.0 mg/cm(2) for 75-90 degrees C, 3.0 mg/cm2 for 50 degrees C. Over these values, the cell performance decreased due to the increases in ohmic and mass transfer resistances. It was found that the peak power density obtained was 217 mW/cm(2) with optimal catalyst and Nafion loading at 75 degrees C using oxygen. (c) 2005 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.

Analysis of estrogens in environmental waters using polymer monolith in-polyether ether ketone tube solid-phase microextraction combined with high-performance liquid chromatography

A simple, rapid and sensitive on-line method for simultaneous determination of four endocrine disruptors (17 beta-estradiol, estriol, bisphenol A and 17 alpha-ethinylestradiol) in environmental waters was developed by coupling in-tube solid-phase microextraction (SPME) to high-performance liquid chromatography (HPLC) with fluorescence detection (FLD). A poly(acrylamide-vinylpyridine-NAP-methylene bisacrylamide) monolith, synthesized inside a polyether ether ketone (PEEK) tube, was selected as the extraction medium. To achieve optimum extraction performance, several parameters were investigated, including extraction flow-rate, extraction time, and pH value, inorganic salt and organic solvent content of the sample matrix. By simply filtered with nylon membrane filter and adjusting the pH of samples to 6.0 with phosphoric acid, the sample solution then could be directly injected into the device for extraction. Low detection limits (S/N = 3) and quantification limits (S/N = 10) of the proposed method were achieved in the range of 0.006-0.10 ng/mL and 0.02-0.35 ng/mL from spiked lake waters, respectively. The calibration curves of four endocrine disruptors showed good linearity ranging from quantification limits to 50 ng/mL with a linear coefficient R-2 value above 0.9913. Good method reproducibility was also found by intra- and inter-day precisions, yielding the RSDs less than 12 and 9.8%, respectively. Finally, the proposed method was successfully applied to the determination of these compounds in several environmental waters. (c) 2006 Elsevier B.V. All rights reserved.

功能性有机薄膜晶体管的研究

有机薄膜晶体管由于具有操作温度低、可以大面积加工和兼容柔性基底等优点，在有源矩阵显示、集成电路和化学传感器等方面显示出广泛的应用潜力。基于这个原因，有关有机半导体材料和器件的研究已经成为当前的热点。从实际应用的角度考虑，当前有机薄膜晶体管的器件性能和单一的工作模式还不能充分的满足实际的需要。因此如何提高有机薄膜晶体管的器件性能、开发多工作模式的器件成为有机电子学领域研究人员的重要挑战。本论文的工作以有机薄膜晶体管器件为主要研究对象。在对二种栅绝缘层的有机薄膜晶体管的研究基础上，提出了有机／无机双介电层有机薄膜晶体管的概念，解决器件的闭值电压和栅源漏电的问题；通过的对有机薄膜晶体管中电荷注入的研究的基础上，提出了含有缓冲层的有机薄膜晶体管，显著的改善了电荷注入效率，提高了器件性能。在对异质结型器件研究的基础上，获得了耗尽型和双极型有机薄膜晶体管，满足实际应用对多种工作模式有机薄膜晶体管的需求。论文的主体工作主要分为基于不同栅绝缘层的有机薄膜晶体管的研究，有机薄膜晶体管中接触效应的研究以及异质结型有机晶体管三个部分其具体内容如下：（l）基于不同栅绝缘层有机薄膜晶体管的研究。通过对有机晶体管中常用的高介电和低介电绝缘层对器件性能的影响进行了系统的研究，在有机晶体管构建中提出了有机／无机双介电层的概念。这一概念包含两个方面意义：一方面采用的双绝缘层分别为一层有机材料和一层无机材料的双介电层；另一方面无机介电层使用的是高介电常数的材料，有机部分为低介电常数材料。有机半导体沉积在这种方法构建的栅绝缘层基底上，改善了有机半导体的薄膜形态，提高了有机半导体层和无机基底的乳附力，从而达到了优化了器件电子性质的目的。与此同时解决了在当前含有高介电绝缘栅的有机晶体管中存在的高漏电的问题。通过这种方法构建的有机薄膜晶体管具有低阂值电压、低漏电、高迁移率等优点。由于我们在有机绝缘层的加工中采用了化学修饰的方法，该方法有加工简便、性质稳定好所以具有很好的实际应用前景。（2）有机薄膜晶体管中接触效应的研究。通过实验中采用TML（Transfer－Line一Method）的方法系统的研究了酞著铜薄膜晶体管中的接触效应，首次获得了酞著铜和金电极接触电阻定量化的结果。通过改变不同的电极材料，研究了不同的源漏电极对有机晶体管器件性能的影响。在此基础上为了能减小有机晶体管中的接触电阻，改善电荷注入效率，我们采用了在源漏电极和有机半导体之间插入一层高电导率的有机材料的方法，有效的降低了金属和有机半导体的注入势垒，增大了电荷隧穿几率，从而显著的改善了有机晶体管的器件性质。（3）异质结型有机晶体管。为了推动有机晶体管在集成互补电路中的应用，多工作模式的有机晶体管是需要的。在这里，我们把有机的异质结引入到有机晶体管的制备中，分别获得了高性能的耗尽型和双极型有机晶体管。通过了一系列的设计实验，我们提出了双沟道的载流子输运模型，为异质结型晶体管中双载流子的输运机制提供了理论上的解释。此外，我们通过有机异质结厚度的调节，进而改变沟道区的载流子密度，从而可以有效的调节了器件的阂值电压。当前的研究结果的意义在于利用的有机的异质结效应可以获得不同阂值电压的全塑型有机晶体管，为其实际中的广泛应用开辟了道路。此外我们还在同一基底上构建了基于一个常开型（耗尽）和一个常关型（累积）两个有机晶体管的反向器电路，从而表明异质结型有机晶体管在集成电路方面具有广泛的应用潜力。综上所述，本论文对目前有机薄膜晶体管器件中存在的问题进行了深入的研究。在此基础上，针对不同的问题分别提出了三种功能性的有机晶体管，优化了器件的性能。当前的研究也将为加速有机薄膜晶体管的在实际中的应用做出贡献。

水稻同源四倍体三系法杂种优势利用研究

水稻是重要的粮食作物，其产量的增加和品质的改良都是关系国计民生的大事。就我国现阶段的国情而言，水稻产量在现有水平上稳步提升仍是未来十几年甚至几十年农业生产最重要的目标之一。尽管根据“超级杂交水稻育种”的战略设想和水稻育种实践，通过不断地改进育种技术可望在更高的产量水平上进行水稻杂种优势利用，在稻属植物内还具有很大的产量潜力可以挖掘。然而，仅仅从现有的种质基础出发，要更大幅度提高水稻单产，实现“超级杂交稻”的目标也存在一些困难：现有的推广品种是二倍体，尽管种类众多，但是其基因组的来源相对单一；同时，水稻基因组DNA含量也是作物中最少的，基因组内寻求开发潜力有一定困难；水稻作为C3植物，光合利用效率不高也是制约水稻产量提高的因素之一。因此，寻求常规手段以外的技术突破或者方法创新，是实现“超级杂交稻”的目标的迫切需求。本研究利用秋水仙素能抑制细胞分裂中纺锤丝的收缩、使细胞染色体加倍的作用，对水稻幼穗诱导的愈伤组织细胞进行加倍，并分化出再生植株；创制出水稻同源四倍体新的种质材料，在此基础上选育水稻同源四倍体雄性不育三系材料，并实现水稻同源四倍体的三系配套，开展水稻同源四倍体杂种优势利用和四倍体杂交水稻选育研究，建立水稻同源四倍体杂种优势利用的新技术体系。这不仅有助于倍性水平杂种优势的开拓和利用，同时也将为我国新世纪“超级稻”育种研究开辟一条新的技术途径。 水稻幼穗诱导愈伤组织并分化成苗是一项成熟、简单的组织培养技术。本研究以普通二倍体水稻亲本为材料，用秋水仙素进行水稻的多倍体化诱导，创制同源四倍体水稻三系亲本材料并对其进行鉴定。多倍体化以秋水仙素诱导的愈伤组织培养为基础，研究不同秋水仙素浓度梯度和愈伤组织诱导培养基组合对诱导四倍体植株的影响。结果表明在MS+2,4 D 1.0mg/L+ KT0.2mg/L+ IAA0.2mg/L 和500mg/L的秋水仙素处理下，水稻愈伤组织染色体加倍（有最高的效率）效果较好，平均加倍频率可达25.26%，其中，材料CDR22和IR26诱导较易成功，加倍频率分别达到75%和26.5%；相对材料94109 1.3%加倍频率和冈46B 10.8%加倍频率，诱导率差异极显著。 对水稻四倍体材料进行了形态学鉴定结果表明，与二倍体水稻对照相比其株高、穗长、花粉育性等主要农艺性状，确定四倍体材料在穗长和千粒重两方面极显著提高，种子的长度和宽度也显著增长。对花粉育性鉴定，确认水稻四倍体不育系材料仍为不育，保持系材料自交和杂交可育，恢复系材料自交和杂交可育。对四倍体材料进行细胞形态、染色体数目等方面进行细胞学鉴定，经核型分析表明水稻四倍体材料具有48条染色体，是二倍体水稻的两倍。水稻四倍体材料根尖分生组织细胞与二倍体的根尖分生组织细胞相比，细胞体积、细胞核和核仁显著增大。四倍体三系材料在细胞有丝分裂中期均可规则排列在赤道板，并能均等地移向两极；后期观察中没有发现染色体分离滞后现象，分裂末期细胞能够形成大小相对均一的子细胞。水稻同源四倍体三系材料细胞分裂未见异常，植株生长发育正常。 从1996年至2006年，针对结实率、有效分蘖、着粒数和穗长等主要农艺性状，通过系谱选育的方法，对培育的同源四倍体水稻亲本材料进行了连续选择和改良，取得较好成效。表现为结实率的改良效果极佳，所有改良材料的平均结实率均呈上升趋势，如D237（29.70％→72.70％）、DTB（19.55％→53.21％）等。有效分蘖总体呈现上升趋势，但在不同的年份，如1998和2002存在较大的负向波动。部分材料改良效果明显，如D19B（5.87→13.50）、D什香 (7.00→12.00)等；同时一些材料如DTB和D明恢63虽然总体略有提高，但在不同的年份波动很大，因此存在较大改良阻力，原因还有待进一步研究。着粒数的改良上升趋势比较显著，除保持系的DTB之外，其余材料的平均着粒数有显著提高。穗长的改良阻力较大，虽然不同材料总体上有所提高，但效果并不显著，并且不同年份有较大负向波动（2001）。此外还对株高、剑叶长等性状也进行了选择，但效果不显著，原因有待进一步提高。同源四倍体材料产量相关性状遗传改良幅度不一致，保持系和恢复系间的遗传改良效果也存在差异。这为同源四倍体水稻的进一步利用打下了良好的基础。 籼稻和粳稻亚种间杂交及杂种优势利用的主要障碍就是其低的结实率。而同源四倍体杂交水稻的研究为提高杂交水稻的杂种优势利用创造了新的途径。本研究通过随机区组设计方案，挑选性状优良的二倍体水稻材料，包括雄性不育系，保持系和恢复系进行秋水仙素诱导加倍，从而获得同源四倍体水稻对应的三系材料。利用选育的优良水稻同源四倍体三系材料，配制7个杂交组合，杂交F1代与其恢复系亲本进行比较，用于计算超亲优势（HB）；而杂交F1代与生产上大面积推广的二倍体杂交品种汕优63进行比较，用于计算杂种优势。结果显示，同源四倍体杂交水稻的超亲优势表现为：每株有效穗变化幅度为1.4%至105.9%，总粒数为0.5%至74.3%，每穗实粒数为17.6%至255.7%，结实率为9.6%至130.4%。这些农艺性状的改良使得这7个杂种F1的理论产量的超亲优势高达64.8%至672.7%。小区试验中四倍体杂交水稻组合T461A/T4002和T461A/T4193分别比二倍体对照汕优63提高46.3%和38.3%以上，除一个品种以外所有品种产量均接近或高于汕优63的产量。同源四倍体水稻强大的杂种优势表明，亚种间杂交育性低的问题可通过四倍体化及强化选择来解决。此外，同源四倍体杂交水稻器官的巨大性也是其产量提高的有利因素，水稻同源四倍体三系杂种优势利用研究具有一定的理论价值和商业生产潜力。 Rice is one of the major food crops, the improvement of the production and quality of it is an important thing related to the people's livelihood. On China's current national conditions, steadily increase of the rice yield based on the current level is still one of the most important goals in the next decade or even decades of agricultural production. According to the "super hybrid rice breeding" the strategic and rice breeding practice, improvement of the use of hybrid rice heterosis through continuous improvements in breeding technology is expected to get a higher level of rice yield, there are also a great yield potential can be exploited. However, there are also some difficulties to increase rice yield obviously and implement the goal of "super hybrid rice" based on the existing germplasm: Rice varieties in promotion are diploid, although there are many varieties, but their genome are from a comparatively single source; Meanwhile, the rice genome DNA are the least among the crops, it is difficult to exploit the development potential within the genome; Rice as C3 plants, photosynthetic efficiency is not high, it is one of the factors constraint rice yield. Therefore, seeking technological breakthroughs or innovative methods different from conventional means is the urgent needs to reach the target of "super hybrid rice". Using colchicine inhibit spindle contraction during cell division, double the cell chromosome, we induced callus cells from rice panicle to be doubled, and differentiated regeneration; we created a new autotetraploid rice germplasm material, and on that basis we bred male sterility three line autotetraploid rice materials, and the achieved the three line rice autotetraploid matchmaking, researched in autotetraploid rice heterosis usage and tetraploid hybrid rice breeding, constituted a new technology system of autotetraploid hybrid rice heterosis utilization. This not only helps the tetraploid rice heterosis exploration and use, but also inaugurates a new technical means for China in the new century "super rice" breeding research. We chose ordinary diploid rice as materials, using colchicine to induce the polyploidization, created the autotetraploid rice three-line materials and identified them. The polyploidization was based on the colchicine-induced callus tissue culture, and we experimented different colchicine concentrations and culture mediums to induce tetraploid plants, confirmed that the optimal concentration for inducement was 500 mg/L, the average induce rate was 25.26 %. Among all the materials, CDR22 and IR26 had higher induced rate; in contrary, 94109 and GANG46B had lower induced rate, the difference was significant. Autotetraploid materials was identified of both morphological and cytological, compared plant height, length of pollen sterility, and other major agronomic traits with a diploid rice as the control plant, identified that the autotetraploid materials had very significant advantages in ear length and thousand-grain weight, as well as the size of the seeds. Cytology identification included observation of the cell morphology, the number of chromosomes, and karyotype analysis on the autotetraploid materials confirmed that their chromosome number was 48, twice of the diploid rice. Mitoses in the three lines were common: chromosomes arrayed normally in metaphase and separated balanced into the two poles, chromosome moved without lagging in anaphase and daughter cells normally formed in telophase except one. It has been proved that tetraploid rice has normal meiosis as their diploid relatives, which usually including series of sub-phases as interphase, prophase I (five sub-phases), prophase II, metaphase I, II, anaphase I, II and telophase I, II. However, abnormal phenomena, such as formation of tetravalent, trivalent and univalent, chromosome lagging and so on, which would finally block meiosis. Configurations of chromosome in metaphaseⅠwere versatile in structure and form accept the bivalent. That condition varied in different strain, suggesting more complex paring configurations and more versatile genetic characters in tetraploid rice. All these abnormalities in meiosis contributed to low fertility of gamete and might consequently resulted in low seed setting. Successive selection and improvement on seed set, productive tiller per plant, total grains per panicle, panicle length and so on had been carried out from 1996 to 2006. The raise of seed sets was significant in both restorers and maintainers. Seed sets of some strains were improved more significantly than others, for example D237（29.70％→72.70％）、DTB（19.55％→53.21％）and et al.. Productive tiller per plant was improved to some extant. The tendency of improvement was rising on the whole but changed in some years such as 1998 and 2002. Part of the stains increased greatly, such as D19B（5.87→13.50）、Dshixiang (7.00→12.00) and so on, but some strains including DTB and Dminghui63 only increased little and decreased in some years by unknown reason. Total grains per panicle increased significantly and all strains except DTB increased. Improvement of panicle length termed to be hard. Different strains showed different capacities for improvement and floating existed in different years for example 2001. It has been proved that other agronomical traits including plant length, flag leaf length and so on could be improved but not significantly by selection also. In a word, agronomical traits could be raised by successive selection that is prerequisite for further utility of autotetraploid rice. Poor fertility is the main barrier for utilizing heterosis between the two rice (Oryza stiva L.) sub-species, indica and japonica. Recently, the development of autotetraploid hybrids (2n=4x=48) has been suggested as a new method for increasing heterosis in hybrid rice. Using standard experimental protocols, the elite diploid rice male sterile, maintainer, and restorer lines were colchine-doubled and autotetraploid counterparts were obtained. Seven resulting hybrids were analyzed for heterobeltiosis (HB), where the F1 was compared to the male parent, and the degree of heterosis, where the F1 was compared to the diploid commercial hybrid, Shanyou 63. The HB among the autotetraploid hybrids ranged from 1.4 to 105.9% for the productive panicles per plant, 0.5 to 74.3% for total kernels per panicle, 17.6 to 255.7% for filled kernels per panicle, and 9.6 to 130.4% for seed set. Improvements in these yield components resulted in the HB for kernel yield ranging from 64.8 to 672.7% among the seven hybrids. Hybrids T461A/T4002 and T461A/T4193 yielded 46.3 and 38.3% more, respectively than Shanyou 63, and all other hybrids but one yielded the same or more than Shanyou 63. The high heterosis for yield suggests that hybrid sterility between two rice sub-species may be overcome by using tetraploid lines followed by intensive selection. Also, the gigantic features of the autotetraploid hybrids may establish a plant structure able to support the higher yield.

Study of the capacitance coupling in accelerators

The relation between the input impedance and the characteristic parameters of a cavity, such as the resonance frequency, shunt impedance and. the quality factor, has been obtained based on the equivalent circuit of the cavity and the coupling system. Using the matching condition, the ratio of coupling capacitance to the equivalent capacitance of the cavity can be acquired as a function of the characteristic parameters of the cavity, the value of the coupling capacitance can be obtained with a help of a numerical simulation and the perturbation theory, and then the perfect matching between the cavity and the transmission line can be procured. The application of these results on a model cavity is presented too.

一种自主越障巡检机器人行走夹持机构

在机器人越障过程中,由于重力的影响使得机器人车体水平姿态发生变化,从而机器人自主越障变得十分困难。分析了超高压输电线路障碍物的类型,提出了一种新的双臂自主越障巡检机器人构型,该构型能够跨越输电线路上的障碍物。针对这种新构型,阐述了机器人行走夹持机构的工作原理和实现形式,着重分析研究了偏心夹持机构对保持车体水平姿态的机理。最后,通过越障实验验证了行走夹持机构的可行性。

输电线巡检机器人控制与实验研究

近年来，机器人的应用越来越广泛和深入，输电线巡检机器人是当前特种作业机器人的研究热点之一，具有广泛的应用前景和实用价值。本文的研究内容是围绕国家“863”计划支持项目“500KV超高压输电线巡检机器人的研究”展开的。本研究工作针对巡检机器人的关键控制问题，主要由三部分组成：设计了巡检机器人的体系结构，并应用离散事件理论对机器人的任务、行为和动作建模；对巡检机器人双轮同步驱动控制进行了分析，并应用奇异摄动理论设计了控制器；研究了基于单目视觉的输电线立体定位方法及通过视觉伺服完成机器人自主抓线控制。 第一，介绍了巡检机器人的作业环境，重点探讨了机器人机械系统和控制系统的设计与实现。在机械子系统中，详细介绍了巡检机器人的机构实现与越障方法。在控制系统中详细阐述了基于分层递阶的机器人控制系统硬件组成。另外介绍了供电系统、无线传输系统、传感系统的设计与实现。分析了输电线路周围的电磁环境，及其对机器人的影响，并根据分析结果完成了对机器人的电磁防护设计。 第二，开展了输电线巡检机器人体系结构及人机交互系统研究，针对巡检机器人工作特点设计了基于规划和感知行为的混合式体系结构。针对巡检机器人工作环境设计了以机器人为中心的人机交互方式。参考前人建立的离散事件动力系统的层次结构和并行结构，提出了顺序结构并证明了其无阻塞性、可控性和监控器存在性，并结合以上三种结构建立了巡检机器人作业行为的离散动力学模型，分别获得了任务层、行为层和动作层的监控器。 第三，进行了巡检机器人双轮驱动控制研究。巡检机器人双轮行走机构为过驱动系统，对双轮行走系统进行了运动学和动力学建模，将一行走轮设为主动轮另一行走轮设为从动轮。针对两行走轮之间弹性关节导致的控制中的振荡问题，采用奇异摄动理论将系统分为快慢两个子系统；针对巡检机器人系统参数的时变性采用PD自适应算法设计了慢系统控制器；应用最优控制理论设计了快系统控制器。仿真结果验证了该方法的有效性。 第四，进行了输电线视觉定位和视觉伺服抓线问题的研究。输电线巡检机器人的自主越障控制是实现机器人实用化的关键问题。为实现巡检机器人自主越障，采用视觉伺服控制机械手臂自动抓线。为提取输电线图像特征点，针对输电线投影图像特征改进了边缘提取算法，应用聚类算法提取了输电线上的像素点。提出在机械手运动过程中采用EKF（扩展卡尔曼滤波）来实现对输电线的立体定位。在分析了当前基于图像的视觉伺服研究现状，建立了基于图像雅克比矩阵的输电线视觉伺服抓线模型。针对非标定状况下图像雅可比矩阵中的不确定参数，应用I&I(Immersion Invariant)自适应算法来实现无标定图像视觉伺服。针对机器人的动力学不确定性，设计了模糊自适应控制器，并证明了稳定性。仿真验证该方法的有效性，实验验证了基于视觉伺服的抓线控制的有效性。

Generation of double pulses in-line by using reflective Dammann gratings

Doubled femtosecond laser pulses in-line are needed in the collinear pump-probe technique, collinear second harmonic generation frequency-resolved optical gating (SHG FROG) and the spectral phase interferometry for direct electric-field reconstruction (SPIDER), etc. Normally, it is generated by using a Michelson's structure. In this paper, we proposed a novel structure with two-layered reflective Dammann gratings and the reflective mirrors to generate doubled femtosecond laser pulses in line without transmission optical elements. Angular dispersion and spectral spatial walk-off are both compensated. In addition, this structure can also compress the positive chirped pulse, which cannot be realized with a Michelson's structure. By adopting triangular grating and blazed gratings, the efficiency of the system would in principle be increased as the Michelson's scheme. Experiments demonstrated that this method should be an alternative approach for generation of the double compressed pulses of femtosecond laser for practical applications. (c) 2006 Elsevier GmbH. All rights reserved.

Eu:Y2O3 nano-phosphor prepared by novel energy-saving solution combustion method

A novel energy- and time-saving solution combustion method has been developed to prepare Eu:Y2O3 nano-crystal line phosphor. This novel method employs anhydrous ethanol as solvent and fuel. The prepared nano-crystals after heat-treatment own narrow size distribution, well dispersibility and sinterability, confirmed by XRD, TEM and FTIR. The emission spectra of nano-Eu:Y2O3 Samples show clear nano-size related phenomena. (c) 2007 Elsevier B.V. All rights reserved.