摘要： Amyloid formation is implicated in a number of human diseases, and is thought to proceed via a nucleation-dependent polymerization mechanism. Experimenters often wish to relate changes in amyloid formation kinetics, for example, in response to small molecules to specific mechanistic steps along this pathway. However, fitting kinetic fibril formation data to a complex model including explicit rate constants results in an ill-posed problem with a vast number of potential solutions. The levels of uncertainty remaining in parameters calculated from these models, arising both from experimental noise and high levels of degeneracy or codependency in parameters, is often unclear. Here, we demonstrate that a combination of explicit mathematical models with an approximate Bayesian computation approach can be used to assign the mechanistic effects of modulators on amyloid fibril formation. We show that even when exact rate constants cannot be extracted, parameters derived from these rate constants can be recovered and used to assign mechanistic effects and their relative magnitudes with a great deal of confidence. Furthermore, approximate Bayesian computation provides a robust method for visualizing uncertainty remaining in the model parameters, regardless of its origin. We apply these methods to the problem of heparin-mediated tau polymerization, which displays complex kinetic behavior not amenable to analysis by more traditional methods. Our analysis indicates that the role of heparin cannot be explained by enhancement of nucleation alone, as has been previously proposed. The methods described here are applicable to a wide range of systems, as models can be easily adapted to account for new reactions and reversibility.

关键词： 机械功   主要问题   优化措施   物理价值  

摘要： 机械功主要有体积功、流动功、轴功、技术功等,其在热能与动力工程中的应用有着巨大的物理价值。本文从机械功的物理价值入手,对机械功应用于热能与动力工程中的应用问题进行了分析,并提出了相应的优化措施,使机械功在热能与动力工程中得到更好的应用,充分发挥价值。

关键词： 热能动力   机械   现状  

摘要： 热能动力机械设备在科学技术的带动下拥有很高的自动化技术,已经完全实现了计算机远程监控作业,尤其是在诸多新能源不断出现的今天,热能动力机械在生产行业的普遍应用其高效节能的优势为市场的快速发展奠定了基础。市场需求的不断提升,使得热能动力机械也需要不断的进步发展,本文首先就热能动力机械的发展现状做出详细分析,然后对其未来的发展方向做出简要的探讨,以供参考。

关键词： 机械工程   多体系系统动力学   领域   问题  

摘要： 随着经济的快速发展,我国的科学技术也有着显著的提高。智能化也有显著的提高,人工智能的推进,促进我国众多工作领域的发展,我们将要见识一种新型的学问----机械工程中的多体系统动力学。多体系统力学在机械工程中起的作用不容小觑。可起促进的作用。本文将通过对多体系统动能力进行解读,让人们更好的理解这一门深奥的学问。之后在对其领域进行分析,并找出其存在的问题。针对问题提出有用的优化方案。

关键词： 工程机械   液压系统动力匹配   控制技术设计   研究  

摘要： 近些年来随着科学技术水平的提高,机电一体化系统在我国的应用越来越广泛。工程机械液压动力系统匹配及控制技术是拥有现代化的理论和技术的高级系统技术。随着机电一体化的发展和广泛应用,液压系统中的阀门液化系统中工程机械的动力匹配,以及其中涉及的各种各样的控制技术得到了水平提升,并且能够进行有效的控制。并且随着社会水平的提升,许多机械液压系统动力匹配和控制技术也迈向越来越复杂的进程,并且也提出了更高的要求。面对这样的情况,本文通过工程机械液压系统动力匹配和控制技术设计进行研究,分析控制技术设计中涉及的各种问题。

关键词： Cadmium sulfide  

摘要： The rational design of high performance hetero-structure photovoltaic devices requires a full understanding of the photoinduced charge transfer mechanism and kinetics at the interface of heterojunctions. In this paper, we intelligently fabricated p-BiOBr/n-CdS heterojunctions with perfect nanosheet arrays by using a facile successive ionic layer adsorption and reaction and chemical bath deposition methods at low temperature. A BiOBr/CdS heterojunction based solar cell has been fabricated which exhibited enhanced photovoltaic responses. Assisted by the surface photovoltage (SPV), transient photovoltage (TPV) and Kelvin probe technique, the photoinduced charge transfer dynamics on the BiOBr nanosheet and p-BiOBr/n-CdS interface were systematically investigated. It was found that the BiOBr/CdS nanosheet array heterojunctions were more efficient in facilitating charge carrier separation than both bare BiOBr and CdS films. The mechanism underlying the photoinduced charge carrier transfer behaviour was unravelled by allying the energy band of BiOBr/CdS p-n junctions from both the interfacial electric field and surface electric field. In addition, the CdS loading thickness in the p-BiOBr/n-CdS heterojunction and the incident wavelength affected greatly the transfer behavior of photoinduced charges, which was of great value for design of photovoltaic devices.

关键词： 动力学建模   重力补偿   动力学控制   PD控制  

摘要： 该文综述了机械臂动力学建模和动力学控制等相关问题,介绍了基于拉格朗日方程的机械臂动力学方程建模方法,并用此方法建立两连杆机械臂动力学方程,介绍了机械臂动力学控制中的无重力补偿的PD控制及仿真、有重力补偿的PD控制及仿真,通过对比仿真图像,指出在机械臂动力学建模和动力学控制中应解决的问题。这对多刚体系统动力学建模与控制问题的研究有一定的促进作用。

关键词： 水下爬行机器人   微分变换   浮力   水阻力   附加质量力  

摘要： 现阶段关于核电站多功能水下爬行机器人在水中运动受浮力、水阻力和附加质量力综合影响的动力学分析研究较少,因此综合考虑上述因素提出了微分变换法构建机械手简化水动力学模型并进行了仿真分析,同时研究了不同水阻力系数和附加质量力系数对水下机械手力矩的影响。仿真结果表明:在静水环境中,浮力力矩是搅水力矩的100倍;附加质量力系数对水下机械手搅水力矩的影响曲线吻合度高于水阻力系数,即附加质量力系数的影响小于水阻力系数。

摘要： A quantum chemical analysis has been performed on the charge transfer/recombination dynamics of a photoactive organic dye having architecture donor-acceptor-donor (D-A-D). Density functional and time-dependent density functional theory calculations reveal that the chromophore shows an excellent charge separation upon excitonic dissociation. The excited state properties were determined by visualizing the charge density difference and transition densities. We evaluate inter electronic coupling matrix on the basis of Generalized Mulliken-Hush model for the dye as well as dye-TiO2 nanocluster and thus we predict the charge transfer and charge recombination rates. Overall, a comparative study between the D-A and D-A-D types of systems has been made to show the effect of one additional donor group on the charge transfer/recombination dynamics. (C) 2017 Elsevier B.V. All rights reserved.

关键词： OXIDATION of carbon monoxide   PRECIOUS metals   CHEMICAL kinetics   REFLECTANCE spectroscopy   X-ray photoelectron spectroscopy  

摘要： Fe2O3 is an attractive catalyst for CO oxidation because of its low cost and reducible nature. Modification in reducible oxide by a noble metal enhances its reducibility. In this work, the effect of noble metal (NM: Pt,Pd) impregnation and substitution on the reaction mechanism for CO oxidation has been studied. Detailed ex situ (X-ray diffraction, XRD;Xray photoelectron spectroscopy, XPS;and transmission electron microscopy, TEM) and in situ diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) characterization were performed along with kinetic studies to develop mechanistic models. Remarkably, the Fe2O3-supported NM exhibited superior catalytic activity than the NM-substituted Fe2O3. Consequently, XPS, photoluminescence, and DRIFTS studies were performed to understand this behavior. Fe2O3 supported NM showed the formation of metal carbonyl bands in DRIFTS studies, however, carbonates were only observed over Fe2O3-supported Pt. On the basis of the spectroscopic evidence and kinetic studies, the Eley-Rideal mechanism was proposed for pristine Fe2O3, whereas noncompetitive and competitive Langmuir-Hinshelwood mechanisms were proposed for Fe(2)O(3-)supported Pt and Pd, respectively.