811 resultados para Autogenous grinding


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本文设计了研磨抛光机器人运动控制器的核心硬件结构和软件模块,采用了参数模糊自整定PID机器人关节位置控制策略,通过实验表明该运动控制器可以大大降低研磨抛光机器人的位置跟踪误差。建立的模块化的软件体系,便于运动控制器的维护和扩展,并可将其应用到其它工业机器人上。

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本文设计了研磨抛光机器人分布式控制系统中的一种运动控制器,并对运动控制器基于AT91M40800微控制器的硬件结构、基于μC/OS-Ⅱ实时操作系统的软件模块和采用的参数模糊自整定PID机器人关节位置控制策略进行了详细介绍。实验表明该控制器可以大大降低研磨抛光机器人的位置跟踪误差。提高了关节控制的计算及处理能力,易于扩展和维护。

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以有机玻璃为研究对象,介绍了机器人研磨抛光工艺,讨论了研磨抛光参数优化设计方法,并进行了研磨抛光试验。试验结果表明,研磨抛光后的工件,能够达到产品外形和表面质量的要求,且提高了磨抛效率。

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提出了一种基于粒子群算法优化(PSO)的模糊控制器,对模糊控制器参数进行全局优化,以弥补模糊控制器参数在线调节方面的不足,并应用于球磨机粉磨系统的控制中。控制系统采用粒子群优化模糊控制器作为双闭环控制中的成品流量控制器,并在Matlab/Simulink进行的仿真分析中实现模糊控制器参数的在线调节。仿真结果表明,系统较好地实现了给定参考轨迹自适应跟踪,具有鲁棒性强、控制精度高等优点。

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以钢坯修磨为实用目的研制的一台机器人化三腿机床,具有刚度大、负载能力强、机构简单、工作空间大、无运动耦合及奇异位形等优点,首次解决了钢坯局部修磨自动化问题,配以其它加工执行器还可实现多种工艺要求。建立了该机床的运动学逆、正解方程,对其工作空间和受力分析进行了介绍,并介绍了局部修磨自动化控制系统

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Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Medicina Dentária

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Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Medicina Dentária

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Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Medicina Dentária

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OBJECTIVE: To examine, for the first time Bcl-2 expression in sequential (autogenous) oral mucosal biopsies taken from the same sites in a gender, risk-factor matched, Caucasoid sample, over a 21-year period,

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This paper describes the creation of a germanium on sapphire platform, via wafer bonding technology, for system-on-a-chip applications. Similar thermal coefficients of expansion between germanium (5.8 x 10-6 K-1) and sapphire (5 x 10-6 K-1) make the bonding of germanium to sapphire a reality. Germanium directly bonded to sapphire results in microvoid generation during post bond annealing. Inclusion of an interface layer such as silicon dioxide layer by plasma enhanced chemical vapour deposition, prior to bonding, results in a microvoid free bond interface after annealing. Grinding and polishing of the subsequent germanium layer has been achieved leaving a thick germanium on sapphire (GeOS) substrate. Submicron GeOS layers have also been achieved with hydrogen/helium co-implantation and layer transfer. Circular geometry transistors exhibiting a field effect mobility of 890 cm2/V s have been fabricated onto the thick germanium on sapphire layer.

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Avoiding the use of solvents in synthesis can reduce environmental contamination and even be more convenient than using solvent-based synthesis. In this tutorial review we focus on recent research into the use of mechanochemistry ( grinding) to synthesise metal complexes in the absence of solvent. We include synthesis of mononuclear complexes, coordination clusters, spacious coordination cages, and 1-, 2- and 3-dimensional coordination polymers ( metal organic frameworks) which can even exhibit microporosity. Remarkably, in many cases, mechanochemical synthesis is actually faster and more convenient than the original solvent-based methods. Examples of solvent-free methods other than grinding are also briefly discussed, and the positive outlook for this growing topic is emphasised.

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The non-hydrolyzable alkylcarbonate analogs of O-acetyl-ADP-ribose have been synthesized from the phosphorylated ribose derivatives after coupling with AMP morpholidate promoted by mechanical grinding. The analogs were assessed for their ability to inhibit the human sirtuin homolog SIRT1. © 2013 The Royal Society of Chemistry.

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Background: Immediate breast reconstruction after mastectomy has increased over the past decade following the unequivocal demonstration of its oncological safety and the availability of reliable methods of reconstruction. Broadly, it is undertaken in the treatment of breast cancer, after prophylactic mastectomy in high-risk patients, and in the management of treatment failure after breast-conserving surgery and radiotherapy. Immediate breast reconstruction can be achieved reliably with a variety of autogenous tissue techniques or prosthetic devices. Careful discussion and evaluation remain vital in choosing the correct technique for the individual patient.

Methods: This review is based primarily on an English language Medline search with secondary references obtained from key articles.

Results and conclusion: Immediate breast reconstruction is a safe and acceptable procedure after mastectomy for cancer; there is no evidence that it has untoward oncological consequences. In the appropriate patient it can be achieved effectively with either prosthetic or autogenous tissue reconstruction. Patient selection is important in order to optimize results, minimize complications and improve quality of life, while simultaneously treating the malignancy. Close cooperation and collaboration between the oncological breast and reconstructive achieve these objectives.

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Various grades of Thermoplastic Polyurethane (TPU) supplied by Bayer were studied to determine their suitability for the rotational moulding process. Following grinding, parts were produced using a variety of peak internal air temperatures and cooling rates. The tensile and impact properties of these parts were then analysed and it was found that both the grade and moulding conditions had a large bearing on the quality and mechanical strength of the part produced.

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Using a small planetary ball mill, liquid-assisted grinding (LAG) of metal salts or oxides (ZnO, CdO, CdCO3, Cu(OAc)(2)center dot H2O, Co(OAc)(2)center dot 4H(2)O, Mn(OAc)(2)center dot 4H(2)O, Ni(OAc)(2)center dot 4H(2)O, FeSO4 center dot 7H(2)O) with two equivalents of isonicotinic acid (HINA) and small amounts of water ( up to 5.6 molar equivalents) gave discrete aquo complexes trans-[M(INA)(2)(OH2)(4)] (M = Zn, Cd, Cu, Fe, Co, Ni, Mn) efficiently within 30 min. For M = Zn, Cd and Cu these complexes readily undergo reversible formal dehydration to the extended network structures [M(INA)(2)] (M = Zn, Cu) or [Cd(INA)(2)(OH2)]center dot DMF by further LAG with non-aqueous liquids such as methanol or DMF. Overall, the mechanochemical dehydrations are more effective than heating or immersion in bulk solvents. The work demonstrates a two-step mechanochemical synthesis of coordination networks via discrete aquo complexes which may be preferable to single step reactions or grinding-annealing procedures in some cases. For example, the two step method was the only way to prepare [Cd(INA)(2)(OH2)]center dot DMF mechanochemically and the porous network Cu(INA)(2) could not be obtained from the aquo complex by heating.