基于加速反馈的直接驱动系统低速摩擦补偿方法实验研究

本文简要地介绍了摩擦的基本原理和目前低速摩擦补偿研究的进展情况。此外，还介绍了直接驱动机器人平台及相关系统软、硬件。本文深入研究了在低速、摩擦条件下常规控制策略的控制效果。给出了三种摩擦效应对系统速度、加速度，开、闭环特性及实际运行性能的影响。作者给出了设计用于低速摩擦补偿的加速度闭环控制方法。通过对三种摩擦介质、三种任务、和不速度下的运行实验来比较有、无积分环节，引入加速度反馈补偿策略系统性能的影响。实现了系统低速运动特性的改善。实验中，摩擦材料的刚性越强，补偿效果越好。而实际工程中大量应用的是刚性极大的材料。因此可以预测加速度反馈补偿控制策略在实际应用中将会有很好的效果。实验结果证明：加速度反馈补偿策略是一种非常好的低速摩擦补偿策略。它不需要过多地了解摩擦的具体特性，不需要对原由控制方法进行大的改动，就可以大幅度地提高系统在低速、摩擦条件下的恒速跟踪、反向、及随动调节任务。同时，在中等速度时，也表现出较好的性能。它大大增强了系统的鲁棒性，具有良好的应用前景。

正交轮移动机器人仿射非线性控制

本文针对具有完整约束的正交轮移动机器人(WMR)的路径跟踪问题，提出了用建立在非线性几何结构理论上的仿射非线性控制方法，该方法不仅可以应用到非线性系统也可以应用于具有强精合系统中.仿真结果表明，该种方法对于移动机器人路径跟踪具有良好的效果。

北大别黄土岭麻粒岩变质演化：对大别造山带演化进程的指示意义

Granulites from Huangtuling in the North Dabie metamorphic core complex in eastern China preserve rare mineralogical and mineral chemical evidence for multistage metamorphism related to Paleoproterozoic metamorphic processes, Triassic continental subduction-collision and Cretaceous collapse of the Dabieshan Orogen. Six stages of metamorphism are established, based on detailed mineralogical and petrological studies: (I) amphibolite facies (6.3–7.0 kbar, 520–550 °C); (II) high-pressure/high-temperature granulite facies (12–15.5 kbar, 920–980 °C); (III) cooling and decompression (4.8–6.0 kbar, 630-700 °C); (IV) medium-pressure granulite facies (7.7–9.0 kbar, 690–790 °C); (V) low-pressure/high-temperature granulite facies (4.0–4.7 kbar, 860–920 °C); (VI) retrograde greenschist facies overprint (1–2 kbar, 340–370 °C). The P–T history derived in this study and existing geochronological data indicate that the Huangtuling granulite records two cycles of orogenic crustal thickening events. The earlier three stages of metamorphism define a clockwise P–T path, implying crustal thickening and thinning events, possibly related to the assembly and breakup of the Columbia Supercontinent ca. 2000 Ma. Stage IV metamorphism indicates another crustal thickening event, which is attributed to the Triassic subduction/collision between the Yangtze and Sino–Korean Cratons. The dry lower crustal granulite persisted metastable during the Triassic subduction/collision due to lack of hydrous fluid and deformation. Stage V metamorphism records the Cretaceous collapse of the Dabieshan Orogen，possibly due to asthenosphere upwelling or removal of the lithospheric mantle resulting in heating of the granulite and partial melting of the North Dabie metamorphic core complex. Comparison of the Huangtuling granulite in North Dabie and the high-pressure (HP)–ultrahigh-pressure (UHP) metamorphic rocks in South Dabie indicates that the subducted upper (South Dabie) and lower (North Dabie) continental crusts underwent contrasting tectonometamorphic evolution during continental subduction–collision and orogenic collapse. High-pressure granulites are generally characterized by the absence of orthopyroxene. However, the Huangtuling felsic granulite rarely preserves the high-pressure granulite facies assemblage of garnet + orthopyroxene + biotite + plagioclase + K-feldspar + quartz. To investigate the effects of bulk rock composition on the stability of orthopyroxene-bearing, high-pressure granulite facies assemblages in the NCKFMASHTO (Na2O–CaO–K2O–FeO–MgO–Al2O3–SiO2–H2O–TiO2–Fe2O3) system, we constructed a series of P–T–X pseudosections based on the melt-reintegrated composition of the Huangtuling felsic high-pressure granulite. Our calculations demonstrate that the orthopyroxene-bearing, high-pressure granulite facies assemblages are restricted to low XAl [Al2O3/(Na2O + CaO + K2O + FeO + MgO + Al2O3) < 0.35, mole proportion] or high XMg [MgO/(MgO + FeO) > 0.85] felsic–metapelitic rock types. Our study also reveals that the XAl values in the residual felsic–metapelitic, high-pressure granulites could be significantly reduced by a high proportion of melt loss. We suggest that orthopyroxene-bearing high-pressure granulites occur in residual overthickened crustal basement under continental subduction–collision zones and arc–continent collision belts.

滇西菲红超基性岩风化壳铂族元素地球化学行为

近年来在世界不同地区进行了风化过程中铂族元素的地球化学行为研究。作为中国西南部的第一个实例． 本文研究了云南西部菲红超基性岩体上发育的红土化风化剖面。矿物学和微量元素地球化学研究证明该风化壳 是超基性岩风化的结果。文中详细讨论了风化壳的地质、矿物学、红土化和铂族元素地球化学特征。结果表明， 风化壳的红土化程度不高，仍处于红色牯土阶段；风化壳上酃的表层土壤带和铁质牯土带中铂族元素总量至少富 集了3 57—7．盯倍，其中Ru和Pd的富集程度较大，Ix的富集程度中等，Pt和弛的富集程度较小，使得铂族元素 的配分模式由基岩的Pt富集型转变为风化壳的Ru-Pt富集型，证明红土化过程中铂族元素发生了分异。

云南大红山层状铜矿床地球化学及成矿机制研究

云南省大红山铁铜矿床位于康滇地轴南端西缘，介于红河深断裂与绿汁江深断裂所夹持的滇中台坳内，赋存于中元古代大红山群海相火山喷流-沉积岩系中，是我国典型的火山岩型块状硫化物（VHMS）矿床之一。该矿床包括一系列与火山喷发-岩浆侵入活动相关但成因有一定差别的矿床，被统称为“大红山式”铁铜矿床。该矿床经济价值巨大，铁、铜储量均达超大型矿床规模，但其研究程度较低，多停留在矿区地质特征层面上，地球化学研究较为薄弱。本次工作系统地研究了大红山层状铜矿床中各类岩石的岩相学特征，对特征矿物做了电子探针定性和定量分析，挑选火山质岩石中锆石做定年分析，系统分析了岩石的主量元素和微量元素，测定了硫化物的硫和铅同位素，并选取了与富集型硫化物相关的石英脉矿物和碳酸盐矿物分别做流体包裹体和碳、氧同位素研究。论文取得的主要认识如下： 1．红山群曼岗河组火山喷流-沉积年代约为1687±8Ma，即形成于早-中元古代，因此不可能遭受如前人所说的吕梁运动改造作用。在700 ~ 800Ma左右，即晋宁运动期本区遭受了强烈的变质变形以及流体蚀变改造作用。 2．层状铜矿中岩石类型主要为黑云母片岩、白云石钠长石岩和白云石大理岩。黑云母片岩中主要矿物为黑云母、钠长石、铁白云石和石榴子石；白云石钠长石岩中主要矿物为钠长石、铁白云石、石榴子石及少量的黑云母；白云石大理岩中主要矿物为铁白云石，含少量的钠长石和黑云母。岩石原岩恢复表明，三类岩石原岩为火山物质、泥质沉积物和喷流热水沉积混合组成，其中黑云母片岩以泥质为主，包含火山质物质和喷流热水沉积物质；白云石钠长石岩以火山物质和喷流热水为主，含少量的泥质；白云石大理岩以热水喷流沉积为主。 3．本区至少遭受过三期变质作用：区域高温变质作用、流体蚀变改造作用和变形变质作用。区域高温变质作用变质温度最高可达可达660℃，主要集中在600 ~ 630℃之间，形成压力约为4.9 ~ 5.0Kbar。三期变质改造使原岩发生了绿帘-角闪岩相的变质作用，变质过程中，稀土元素（特别是轻稀土元素）和部分高场强元素发生了迁移；流体蚀变改造富集了早期的贫铜矿胚，使之形成工业矿床。 4．硫化物硫同位素研究显示，其δ34S值为-0.6 ~ +10.9‰，主要集中在+5.0 ~ +10.9‰之间。这一组成表明富集型硫化物大体继承了早期硫化物硫源特征，并在改造过程中富集重硫。早期硫化物硫源主要来自岩浆硫和海水无机还原硫。硫化物铅同位素范围为：206Pb/204Pb＝ 18.985 ~ 23.318，均值为21.222；207Pb/204Pb＝15.581 ~ 15.904，均值为15.747；208Pb/204Pb＝39.803 ~ 45.652，均值为42.540。显然，本区硫化物具有极高含量的放射性成因铅，部分放射性成因铅含量稍低的样品与前人所圈定的改造型矿床的硫化物铅同位素范围较为吻合。分析认为，本区硫化物铅同位素代表了两种不同铅源的混合，即早期硫化物的普通铅和围岩中的放射性成因铅。硫铅同位素示踪以及矿相学研究表明，本区早期铜质来源于海底火山喷流-沉积，而晚期富集型铜矿铜质继承了早期铜质，同时也不排除晚期流体中所带来的铜质。 5．流体包裹体研究表明，本区改造型流体中包括三种流体体系：①中-低盐度H2O-NaCl±KCl±FeCl3 ±CaCl2流体，盐度范围为0.53 ~ 24.59 % NaCl equiv.，密度为0.80 ~ 1.16 g/cm3；②高盐度高密度H2O-NaCl±CaCl2流体，盐度为31.2 ~ >59.76% NaCl equiv，密度为1.14 ~ 1.45 g/cm3；③纯液相CO2流体，流体密度为0.77 ~ 1.09 g/cm3。流体包裹体均一温度在100 ~ 456℃之间，主要集中在150 ~ 260℃和260 ~ 456℃两个温度区间。方解石碳、氧同位素范围分别为-5.6 ~ -3.1‰和12.4 ~ 15.5‰。综合分析表明，流体主要来自海底下伏岩浆房的出溶或喷流的高温高盐度流体，部分与海水混合。流体在热液改造过程中活化富集了早期硫化物，经过短距搬运而沉积形成了晚期富集型硫化物。 6．本次研究确定该矿床的成矿机制为：早-中元古代，本区的陆内裂谷作用为火山喷发提供了构造条件，海底火山喷流-沉积形成了早期的贫铜矿胚。元古代末期，本区遭受了强烈的区域变质、变形和流体蚀变改造作用，使原先的贫铜矿胚得到活化富集，形成了工业矿床。

LED (660 nm) and laser (670 nm) use on skin flap viability: angiogenesis and mast cells on transition line

Skin flap procedures are commonly used in plastic surgery. Failures can follow, leading to the necrosis of the flap. Therefore, many studies use LLLT to improve flap viability. Currently, the LED has been introduced as an alternative to LLLT. the objective of this study was to evaluate the effect of LLLT and LED on the viability of random skin flaps in rats. Forty-eight rats were divided into four groups, and a random skin flap (10 x 4 cm) was performed in all animals. Group 1 was the sham group; group 2 was submitted to LLLT 660 nm, 0.14 J; group 3 with LED 630 nm, 2.49 J, and group 4 with LLLT 660 nm, with 2.49 J. Irradiation was applied after surgery and repeated on the four subsequent days. On the 7th postoperative day, the percentage of flap necrosis was calculated and skin samples were collected from the viable area and from the transition line of the flap to evaluate blood vessels and mast cells. the percentage of necrosis was significantly lower in groups 3 and 4 compared to groups 1 and 2. Concerning blood vessels and mast cell numbers, only the animals in group 3 showed significant increase compared to group 1 in the skin sample of the transition line. LED and LLLT with the same total energies were effective in increasing viability of random skin flaps. LED was more effective in increasing the number of mast cells and blood vessels in the transition line of random skin flaps.

Caratterizzazione geo-petrografica, petrologica e geochimica di rocce anatettiche del nord Sardegna

The High Grade Metamorphic Complex (HGMC) of Variscan basement of north Sardinia is characterized by the widespread of migmatites. This study is focused on two localities of NE Sardinia (Porto Ottiolu and Punta Sirenella) where ortho- and para-derivates migmatites outcrop. A geological and structural survey was carried out, leading to the realization of a geological schematic map of Punta Sirenella area. Several samples of different rocks were collected for petrographic, micro-structural minero-chemical and geochemical analyses. In the Porto Ottiolu area three main deformation phases have been identified; D1, characterized by tight folds with sub-horizontal axes, rarely preserved in paragneisses; D2, that produce a pervasive foliation oriented N100° 45°SW marked by biotite and sillimanite blastesis and locally transposed by shear zone oriented N170°; D3, late deformation phase caused symmetric folds with sub-horizontal axes with no axial plane schistosity. Leucosomes form pods and layers along S2 schistosity but also leucosomes along shear zones have been observed. In the Punta Sirenella area, three main deformation phases have been identified; D1, is manifested by the transposition of centimeter-sized leucosomes and is rarely observed in paragneisses were produce open folds with sub-vertical axes; D2, NW-SE oriented on whose XY plane three mineralogical lineation (quartz+plagioclase, fibrolite+quarz and muscovite) lie; D3, a ductile-brittle deformation phase that produce a mylonitc S3 foliation that locally become the most evident schistosity in the field oriented N140° steeply dipping toward NE. In both areas, leucosomes of sedimentary-derived migmatites are generally trondhjemitic pointing out for a H2O fluxed melting reaction, but also granitic leucosomes have been found, produced by muscovite dehydration melting. Leucosomes of migmatitic orthogneiss instead, have granitic compositions. Migmatization started early, during the compressional and crustal thickening (sin-D1, pre-D2) and was still active during exhumation stage. For each studied outcrop of migmatite pseudosections for the average mesosome composition have been calculated; these pseudosections have been used to model the P-T conditions of anatexis on the basis of the melt volume (%) of melt, Si/Al and Na/K molar ratios, modal content of garnet and Si content in metamorphic white mica. Further pseudosections have been calculated for the average composition of leucosomes in order to define the P-T conditions of the end of the crystallization through intersection of solidus curve and isopleths of Si content in white mica and/or XMg ratio in biotite. Thermodynamic modeling on ortho- and sedimentary-derived migmatites of Punta Sirenella yield P-T conditions of 1.1-1.3 GPa - 670-740°C for migmatitic event and 0.75-0.90 GPa - 660-730°C for the end of crystallization. These conditions are fit well with previous studies on adjacent rocks. Modeling of Porto Ottiolu ortho- and sedimentary-derived migmatites yield P-T conditions of 0.85-1.05 GPa - 690-730°C for migmatitic event and 0.35-0.55 GPa - 630-690°C strongly affected by re-equilibration during exhumation, expecially for crystallization conditions. Geochemical analyses of samples belonging to Porto Ottiolu and Punta Sirenella orthogneisses show a strong link with those of other orthogneisses outcropping in NE Sardinia (for instance, Lode-Mamone and Golfo Aranci) that are considered the intrusive counterparts of middle-Ordovician metavolcanics rocks outcropping in the Nappe Zone. Thus, the studied ortogneiss bodies, even lacking radiometric data, can be considered as belonging to the same magmatic cycle.

LA Size in Former Elite Athletes

A recent meta-analysis by Iskandar et al. (1) nicely showed that endurance athletes have larger left atrial (LA) diameters compared with control subjects. Yet only 9 of 54 studies included in their analysis reported LA volume values corrected for body surface area (BSA). In fact, few studies have determined LA volume in young athletes, and, to the best of our knowledge, no study has reported this variable in older athletes. This is an important question given the growing debate about the potential deleterious effects of long-term strenuous endurance exercise on the human heart, notably the higher risk of atrial fibrillation (AF), a condition for which both atrial dilation and the normal aging process are thought to be potential causative mechanisms (2). Thus, we aimed to assess the long-term consequences of endurance exercise on LA volume in athletes who were highly competitive at younger ages and are still active. To this end, we compared BSA-corrected LA volumes determined with late gadolinium enhancement magnetic resonance imaging (LGE-MRI) in former elite endurance athletes and sedentary control subjects.

The Scientist Who Came in from the Cold: Heinz Barwich's Flight from the GDR

Maddrell, John, 'The Scientist Who Came in from the Cold: Heinz Barwich's Flight from the GDR', Intelligence and National Security (2005) 20(4) pp.608-630 RAE2008

The Impact of Sunspots on the Interpretation of Coronal Observations of the O VI Doublet

Morgan, Huw; Habbal, S. R., 'The impact of sunspots on the interpretation of coronal observations of the OVI doublet', The Astrophysical Journal (2005) 630(2) pp.L189-L192 RAE2008

Desarrollo de una colección de productos.

[61] hojas : ilustraciones, fotografías.

Christian missions and a new world culture

http://www.archive.org/details/christianmission027881mbp

Schema-driven construction of future autobiographical traumatic events: the future is much more troubling than the past.

Research on future episodic thought has produced compelling theories and results in cognitive psychology, cognitive neuroscience, and clinical psychology. In experiments aimed to integrate these with basic concepts and methods from autobiographical memory research, 76 undergraduates remembered past and imagined future positive and negative events that had or would have a major impact on them. Correlations of the online ratings of visual and auditory imagery, emotion, and other measures demonstrated that individuals used the same processes to the same extent to remember past and construct future events. These measures predicted the theoretically important metacognitive judgment of past reliving and future "preliving" in similar ways. On standardized tests of reactions to traumatic events, scores for future negative events were much higher than scores for past negative events. The scores for future negative events were in the range that would qualify for a diagnosis of posttraumatic stress disorder (PTSD); the test was replicated (n = 52) to check for order effects. Consistent with earlier work, future events had less sensory vividness. Thus, the imagined symptoms of future events were unlikely to be caused by sensory vividness. In a second experiment, to confirm this, 63 undergraduates produced numerous added details between 2 constructions of the same negative future events; deficits in rated vividness were removed with no increase in the standardized tests of reactions to traumatic events. Neuroticism predicted individuals' reactions to negative past events but did not predict imagined reactions to future events. This set of novel methods and findings is interpreted in the contexts of the literatures of episodic future thought, autobiographical memory, PTSD, and classic schema theory.