The crystal structure and drawing-induced polymorphism in poly(aryl ether ketone)s .2. Poly(ether ether ketone ketone), PEEKK

The crystal structure, morphology and polymorphism induced by uniaxial drawing of poly(ether ether ketone ketone) [PEEKK] have been studied by transmission electron microscopy (TEM), electron diffraction (ED) and wide angle X-ray diffraction (WAXD). On the basis of WAXD and ED patterns,the crystal structure of unoriented PEEKK is determined to have two-chain orthorhombic packing with unit cell parameters of a 0.772 nm, b = 0.600 nm, c = 1.004 nm (form I), A stress-induced crystal modification (form II) is identified and found to possess a two-chain orthorhombic lattice with unit cell dimensions of a = 0.461 nm, b = 1.074 nm, c = 1.080 nm. The 7.5% increase in c-axis dimension for form II is attributed to an overextended chain conformation, arising from extensional deformation during uniaxial drawing and fixed ''in-situ'' through strain-induced crystallization. The average ether-ketone bridge bond angles in form II crystal are determined to be 148.9 degrees by using standard bond lengths. The crystal morphology of PEEKK bears a great similarity to that of PEEK. The crystals grow in the form of spherulites and have the b-axis of unit cell radial. The effects of draw rate on strain-induced crystallization and induction of form II structure are also discussed.

老年性白内障晶状体中金属元素的人工神经网分析

由Ｋ、Ｎａ、Ｃａ、Ｍｇ、Ｆｅ、Ｃｕ、Ｚｎ和Ｍｎ在老年性晶状体中的含量，运用人工神经网法成功地将老年性白内障、白内障晶状体核和正常人晶状体划分为３类。同时讨论了神经网的结构（层数及每层的结点数）、初始权重等对神经网性能的影响。随机地将３０个晶状体分为训练集和测试集，其识别率及预测率均达到１００％。

SYNTHESIS AND SPECTRAL CHARACTERISTICS OF DIVALENT SAMARIUM ACTIVATED BINARY FLUORIDES

A simple technique for preparation of powder binary fluorides activated with divalent samarium ions is described. The samarium impurity is introduced as samarium trifluoride SmF3 and hydrogen acts as the reducing agent to transform Sm3+ into Sm2+. Using this method, samarium has been stabilized in the divalent state in some fluorides: KMgF3, LiBaF3, BaBeF4, SrMgF4 and BaMgF4. Moreover, BaBeF4, SrMgF4 and BaMgF4 have never been activated with Sm2+ ions up to now. We also find that under the same synthetic conditions samarium can not be stabilized in the divalent state in some fluorides: KCaF3, CaBeF4 and CaMgF4, but the characteristic luminescence of trivalent samarium Sm3+ appears in these matrices. The emission and excitation spectra of samarium (Sm2+ and Sm3+) in these binary fluorides are presented and briefly discussed. The relationship between the oxidation state of samarium and the composition, the structure of matrices is also analyzed.

一种简易型顺磁波谱电化学池的设计和卟啉π-阳离子自由基的检测

设计了一种简易型全玻璃ESR薄层现场波谱电化学池,以高7mm,直径0.5mm的铂柱工作电极安放在直径1mm的玻璃管中,形成体积为4.7μl的薄层池,2ml溶液就可以工作。在二氯乙烷中,进行了薄层电化学性能表征,并对(TPP)H_2的电极氧化过程进行了研究,发现电生的(TPP)H_2阳离子自由基有动力学后行反应。可能的机理是自由基岐化反应伴随着Cl~-引起的异卟啉的生成反应。

二价钐激活复合氟化物磷光体的合成及光谱特性

报道了合成二价钐激活的复合氟化物的简单方法。用H_2作还原剂,用高温固相反应直接制得8m~(2+)激活磷光体:KMgF_3,LiBaF_3,BaBeF_4,SrMgF_4和BaMgF_4等,其中BaBeF_4,SrMgF_4和BaMgF_4中掺入Sm~(2+)为首次报道。在KCaF_3,CaBeF_4,SrBeF_4和CaMgF_4中只观察到Sm~(3+)发射而无Sm~(2+)发光。分析了钐离子价态与基质组成结构间关系,讨论了钐离子(8m~(2+)和Sm~(3+))的光谱特征。

黄河口及其附近海域砷的分布，沉积物中砷的生物可利用性及粒度校正的研究

氮、磷、砷在周期表中位于同一主族，氮和磷是营养元素，而砷却是有毒的元素。砷在海水中有三价、五价二种存在形式。它们是如何分布变化的？它在沉积物中的含量与底栖生物是否有关？黄河口是我国研究得较少的一个海区，带着上述问题，我们于1989年5月（枯水期）和8月（丰水期）进行了二个航次的调查。除得到了砷在海水、沉积物中的分布外还得到如下结果：一、黄河口区三价和五价砷的平均含量如表所示：在热力学平衡时，海水中的砷主要应以砷酸盐（五价）形式存在。但黄河口区三价砷的存在量点总砷的0－70％。通过与叶绿素a的相关分析得知，三价砷是浮游植物产生的。但在低温时（低于13℃），即使浮游植物量很高也不产生三价砷。二、沉积物中砷的含量与沉积物的粒径有关：细粒径的沉积物含砷较高。粗粒径的沉积物含砷较低。但在河口，由于流速大沉积物多为粗粒径的。河水中砷含量比海水高，而河口沉积物中砷含量往往比附近海区沉积物中的低，不能反映河水中砷高的情况，为此做了沉积物比表面的较正，前人用比表面校正时发现比表面和重金属含量在低表面时呈线性关系，随着比较表面增大，重金属含量不再增加，我们认为沉积物可以分成二部分：一部分是岩石碎屑、粘土矿等组成，这部分中的砷是生物不能吸收利用的“非活性”部分；另一部分是水合氧化物、有机质等组成的，其中的砷能被生物摄取（“活性”部分），而且也只有“活性”部分才是和沉积物比表面有关。通过研究得到以下有意义的结果：1、用1MHCl提取沉积物中的“活性”砷，其含量和相应位置采集到的四角蛤蜊（Mactra Veneriformis Reeve）中砷含量具有良好的线性关系。说明对砷来说1MHCl和四角蛤蜊消化液具有同样的效力。2、沉积物外比表面和“活性”砷之间有很好的线性关系。我们提出了以每平方米沉积物外表面积含活性砷量作为沉积物中砷的评价单位，克服了沉积物粒径不同的影响。上述方法可以推广到沉积物中其它污染物质的研究上去。上述方法对制订沉积物的环境质量标准是有参考价值的，因为环境质量标准是要以生物的毒理试验为依据的。

高寒草甸不同海拔梯度土壤有机质氮磷的分布和生产力变化及其与环境因子的关系

以高寒草甸6个不同海拔(从低到高依次为3 840,3 856,3 927,3 988,4 232,4 435 m)梯度内的野外观测和土壤实测数据,分析了土壤有机质、氮、磷的分布特征及其与土壤含水量和土壤温度之间的关系.结果表明,土壤有机质、土壤全氮、土壤速效氮、土壤全磷含量均在第一梯度(3 840 m)和第六梯度(4 435 m)较高,中间梯度较低,但土壤速效磷变化有波动;土壤含水量对土壤有机质、氮、磷作用强度依次为土壤全氮、土壤有机质、土壤全磷、土壤速效氮、土壤速效磷;土壤温度对土壤有机质、氮、磷作用强度依次为土壤速效氮、土壤有机质、土壤全氮、土壤全磷、土壤速效磷;温度对高寒草甸植物群落初级生产力(地上生物量)的作用最大,是决定不同海拔梯度植物群落初级生产力的主要环境因子,其回归方程为:Ya＝-92.982+13.832X3(F＝13.355,P<0.05).

高寒草甸珠芽蓼抗氧化物质含量的季节变化及与太阳辐射的关系

对高寒草甸珠芽蓼中几种抗氧化物质含量的季节变化测定发现, 珠芽蓼叶片内抗坏血酸、超氧阴离子自由基的相对含量、超氧化物歧化酶的活性以及紫外辐射吸收色素在5月至8 月间呈现“拱型”曲线变化, 不同物质分别以6、7月份最高, 分别与海北站地区的太阳辐射呈现一定的相关性。

移动机器人的障碍物群检测方法

利用激光和超声波传感器在用栅格表示法形成地图的基础上 ,提出了进行数据融合以提取环境特征的新方法 :识别障碍物群。该方法能够在密集障碍物环境中为机器人的路径规划和避障提供准确的环境特征信息 ,提高机器人系统的自主性和实时性。实验结果表明了该方法的有效性。

理性遗传算法及其在多机器人运动协调中的应用

面对传统遗传算法在解决一些复杂问题时所存在的收敛慢或早熟等困难 ,基于仿人理性决策原则 ,提出一种具有更丰富进化含义的进化算法——理性遗传算法 .其通过遗传信息的反馈或理性规则的建立来指导遗传操作的进行 ,从而将种群内部知识与经验的继承和学习更有效地结合在遗传算法之中 .相对于传统遗传算法 ,较好地解决了多机器人确知环境下协调运动规划问题 .理论分析和仿真实验结果都是令人鼓舞的 .

移动机器人激光全局定位系统的算法研究

介绍了一种新型的移动机器人激光全局定位系统。重点讨论了结构化环境中移动机器人的全局定位方法 ,提出了一种新的基于最小二乘法的迭代搜索定位算法。全方位移动机器人平台上进行的定位实验 ,证实了该算法的有效性。

准噶尔盆地西缘车排子地区隐蔽油气藏识别与勘探目标研究

After the half century exploration, previous scholar evaluating thought that there were poor Petro-Geological conditions in Chepaizi area of Zhungar basin. Recently, with the great discovery in the Well Pai2,the study on the subtle reservoir in Chepaizi area are gained great attentions by the scholars all over the world day by day. Chepaizi uplift is a inherited palaeohigh, and its structural traps are undeveloped. The sedimentary faces of Shawan Formation of Neogene have apron type of alluvial fan, alluvial plain, alluvial fan delta, salt lake, shore and shallow lake and so on. The sedimentary faces of Shawan Formation of Well Pai2 is alluvial fan delta and shore and shallow lake, the first part of Shawan Formation(N1s1) is the main target for exploration. Using the seismic forward, property analysis, spectral factorization, logging restrain inversion and so on, The spatial distribution of the sand reservoir and its hydrocarbon, predicted and 20 lithology traps in 5 substratums were carried out. The traps have a total areal of 107.13 Km2, and the geological reserves in it can reach 8703.7×104t. After comprehensive research on the trap,reservoir, cap and the condition of the hydrocarbon accumulation, it is considered that the elements of hydrocarbon in Chepaizi area are various. Because it can’t generate hydrocarbon, the oil and gas conducting and accumulation are the most important factors in this area, and the validity of the lithology traps in monoclinal is another important factor. Research indicates that the master control factor of the subtle reservoir in Chepaizi area is fault and sand. The sand of beach and sandbar provide the space for the hydrocarbon accumulation, the fault provides the migration channel for the hydrocarbon. Most faults have a characteristics of up seal and the down open, which not only can conduct hydrocarbon, but also can prevent hydrocarbon overtopping, therefore the effect trap is results of good match of fault and sand.

Huanglongbing (ex-greening): um alerta aos citricultores da Bahia.

A produção de citros no Brasil é uma das principais atividades do agronegócio nacional, apresentando significativa importância econômica e social devido aos números vultosos de produção. A Bahia destaca-se como o segundo produtor nacional de laranja. Para manter esse desempenho, cuidados devem ser empregados a fim de garantir a sanidade dos pomares do estado. Dentre as doenças que afetam os citros, o huanglongbing (HLB), comumente chamado de ?greening? é altamente devastador e amplamente distribuído no mundo. Essa doença tornou-se importante no cenário brasileiro desde 2004, quando ocorreram os primeiros registros no estado de São Paulo. O HLB é causado pela bactéria Candidatus Liberibacter, que no Brasil está associada às formas Ca. L. asiaticum e Ca. L. americans. A disseminação do HLB pode ocorrer por enxertia de material contaminado ou pelo inseto vetor da bactéria, o psilídeo Diaphorina citri Kuwayama (Hemyptera: Psyllidae). Além dos citros, o D. citri também utiliza como hospedeiro a espécie Murraya paniculata, popularmente conhecida como murta.

Error Detection and Recovery for Robot Motion Planning with Uncertainty

Robots must plan and execute tasks in the presence of uncertainty. Uncertainty arises from sensing errors, control errors, and uncertainty in the geometry of the environment. The last, which is called model error, has received little previous attention. We present a framework for computing motion strategies that are guaranteed to succeed in the presence of all three kinds of uncertainty. The motion strategies comprise sensor-based gross motions, compliant motions, and simple pushing motions.