关键词： MOLECULAR rotation   ROTORS -- Dynamics   STATORS   ROTATIONAL motion   SOLID state electronics   X-ray diffraction   ACTIVATION (Chemistry)   TEMPERATURE effect  

摘要： Samples of 4,4'-bis(3,3,3-tri-d(5)-phenylpropynyl)biphenyl 2, 9,10-bis(3,3,3-tri-d(5)-phenylpropynyl)anthracene 3, 1,4-bis(3,3,3-tri-d(5)-phenylpropynyl)naphthalene 4, and 4,4'-bis(3,3,3-tri-d(5)-phenylpropynyl)-1, 1'-bi naphthyl 5 were prepared via a Sonogashira coupling of 3,3,3-tri-d(5)-phenylpropyne 7 and the appropriate aryl dibromide. Single crystal X-ray diffraction structures were obtained for an o-xylene clathrate of 2 and for solvent-free crystals of 3. All four molecular rotors were characterized by CPMAS C-13 NMR experiments with varying contact times in order to determine whether the carbon signals of the central rotator group could be selectively enhanced and studied without interference or overlap of signals from the deuterated stator, which is insensitive to the {H-1}-C-13 cross-polarization method. It was shown that the C-13 signals of the natural abundance rotator group can be selectively observed with short contact times (ca. 50 mu s) without interference from other C-13 signals in the molecule. Variable-temperature CPMAS C-13 NMR studies with a crystalline o-xylene solvate of biphenylene rotor 2 suggested a 2-fold flipping process in the fast exchange regime, even at temperatures as low as 199 K (-74 degrees C). Indirect support for this was obtained by studies carried out with a disordered, solvent-free solid, obtained by fast precipitation from hexanes and dichloromethane, which displayed slower dynamics within the same temperature range with an activation energy of 8.7 kcal/mol and a pre-exponential factor of 4.9 x 10(9) s(-1). Confirmation of an exchange process in the megahertz regime for the crystalline solvate was obtained by variable-temperature quadrupolar echo H-2 NMR data acquired with samples prepared with a deuterated biphenylene rotator and a natural abundance stator. Although rotational exchange occurs in the solvated samples with a slightly lower barrier of 7.4 kcal/mol, the main difference with the precipitated solid comes from t

关键词： morphological communication   morphological computation   tensegrity   robotics  

摘要： Traditional engineering approaches strive to avoid, or actively suppress, nonlinear dynamic coupling among components. Biological systems, in contrast, are often rife with these dynamics. Could there be, in some cases, a benefit to high degrees of dynamical coupling? Here we present a distributed robotic control scheme inspired by the biological phenomenon of tensegrity-based mechanotransduction. This emergence of morphology-as-information-conduit or 'morphological communication', enabled by time-sensitive spiking neural networks, presents a new paradigm for the decentralized control of large, coupled, modular systems. These results significantly bolster, both in magnitude and in form, the idea of morphological computation in robotic control. Furthermore, they lend further credence to ideas of embodied anatomical computation in biological systems, on scales ranging from cellular structures up to the tendinous networks of the human hand.

关键词： 机械支承系统   频谱分析   故障  

摘要： 针对2个典型动力机械支承系统故障案例,结合诊断原理,综合运用频谱分析、逆向推导、考虑运行史和检修史等多种诊断方法,准确地诊断出故障的根本原因,使设备隐患得以消除。

关键词： 结构阻尼   结合部   有限元   复特征值分析   模态试验  

摘要： 机械结合部的阻尼由连接界面之间的相对滑动产生,为结构阻尼,因此提出了一种基于结构阻尼的结合部动力学模型。该模型通过刚度和结构阻尼对机械结合部进行等效,模拟结合部的动力学特性。为了对模型进行验证,设计了一组试验进行研究。首先利用DASP系统对试验件进行模态试验,得到模态参数和模态振型,然后根据模态试验数据识别机械结合部动力学参数。基于新模型的有限元复特征值分析结果与模态试验分析结果误差较小,表明结合部动力学模型在设置适宜的参数时,能够模拟机械结合部的动力学特性,验证了模型的可行性。

关键词： 两相流   渣浆泵   密封   数值模拟  

摘要： 文章通过设计一种用于固液两相流泵的流体动力与机械组合密封的密封件,建立了较为完善的计算流体动力学分析模型。FLUENT计算选用标准k-ε湍流模型,对固液两相流泵密封件内部流场三维湍流流动进行了数值模拟。利用数值模拟的结果分析了固液两相在泵密封件内部流场三维湍内的流动状况。最后进行整机实验验证,结果表明:采用组合密封的液固两相流泵的泄露量减少,耐磨寿命大大提高。

关键词： 中国北方   装备制造业   技术展览会   基础零部件   国际化   动力传动   工业市场   东北老工业基地  

摘要： 中国北方市场奠定了国民经济重要的产业体系，汇集了众多领先的大型企业和特大型企业，是多产业、高价值、实力强、重要的工业基地。尤其是国家出台了一系列区域振兴政策和产业振兴政策，如东北老工业基地的振兴、京、津、冀环渤海经济圈的发展，以及汽车工业、装备制造业、轻工行业、钢铁行业等产业振兴规划后，该地区的发展速度和可持续性将得到极大提升。

关键词： 动力机械   山东省   发动机制造商   通用汽油机   高新技术开发区   公司简介   自主研发   制造企业  

摘要： 公司简介：山东华盛中天动力机械有限公司（原山东汽油机厂），是山东华盛中天机械集团有限公司的全资子公司，江北最大的四冲程通用发动机制造商，公司占地15万平米，位于山东省临沂市高新技术开发区，是一家集自主研发、制造检测、推广营销为一体的专业化制造企业。公司专业生产四冲程通用汽油机、柴油机、水泵、发电机组、舷外机等五大系列100多个品种。

关键词： 动力机械泵   凝结水回收   结构   工作原理  

摘要： 介绍了用于凝结水回收的动力机械泵结构及工作原理。结合凝结水回收工程实例,分析了动力机械泵的经济性及运行效果。动力机械泵的经济性优于传统凝结水回收系统,运行稳定,故障率低。

关键词： 柔性机械臂   压电元件   动力学建模   拉格朗日方程   Newmark法  

摘要： 以压电双杆柔性臂为研究对象,采用Euler-Bernoulli梁模型简化机械臂,运用假设模态法描述弹性变形,将压电元件对臂的作用等效为一驱动力矩,依据拉格朗日方程推导耦合动力学方程,并利用Newmark法进行迭代求解。仿真与实验验证了动力学模型的有效性,模型具有准确、简单等特点,为后续振动控制的实施奠定了理论基础。

关键词： 液力机械自动变速器   动力性换挡点   算法  

摘要： 为得到发动机与液力变矩器共同工作点及动力性换挡点精确计算结果,对发动机净转矩外特性曲线采用三次样条插值,并构造了求解共同工作点及动力性换挡点的求值函数,分别采用改进二分法和牛顿下山法来求解构造函数零值。通过实例计算和分析表明,这2种方法运行速度快、精度高,求得的动力性换挡特性提高了液力传动车辆的匹配效率。