配电自动化系统实时分布式数据库(RDDB)研制

介绍为配电自动化系统研制的实时分布式数据库（ＲＤＤＢ）．ＲＤＤＢ实现了层次模型,并设计采用了一种兼顾顺序存取和随机快速存取的数据存取方法． 该方法通过对数据库中的记录建立ＨＡＳＨ表和链表,实现了单个数据快速随机检索和批量数据的顺序检索．ＲＤＤＢ具有占用空间少、实时性高和操作方便的特点,满足配电自动化系统的要求．     

X射线数字化实时成象技术在天然气管道焊缝探伤中应用的可行性

X射线数字化实时成象检测技术在天然气长输钢制管道对接焊缝探伤中应用是可行的,并能取得良好的经济效益和社会效益,可在西气东输工程中采用。     

Real-time generation and control of cutter path for 5-axis CNC machining

This paper presents a new approach to real-time generation and control of the cutter path for 5-axis machining applications. The cutter path generation method comprises real-time algorithms for cutter-contact path interpolation, cutter offsetting, and coordinate conversion. In addition, a global feedback loop is closed by the CNC interpolator so as to augment the controlled accuracy in practical cutter path generation. An error compensation algorithm and a feedrate adaptation algorithm for the control loop are developed, respectively.     

Real time spectroscopic ellipsometry of Ag/ZnO and Al/ZnO interfaces for back-reflectors in thin film Si:H photovoltaics

Real time spectroscopic ellipsometry (RTSE) has been applied to analyze the optical characteristics of Ag/ZnO and Al/ZnO interfaces used in back-reflector (BR) structures for thin film silicon photovoltaics. The structures explored here are relevant to the substrate/BR/Si:H(n-i-p) solar cell configuration and consist of opaque Ag or Al films having controllable thicknesses of microscopic surface roughness, followed by a ZnO layer up to ~ 3000 Å thick. The thicknesses of the final surface roughness layers on both Ag and Al have been varied by adjusting magnetron sputtering conditions in order to study the effects of metal film roughness on interface formation and interface optical properties. The primary interface loss mechanisms in reflection are found to be dissipation via absorption through localized plasmon modes for Ag/ZnO and through intraband and interband transitions intrinsic to metallic Al for Al/ZnO.     

复杂网络中节点暂态中心性预测研究

对复杂网络中节点的3种暂态中心性进行了预测研究。通过在真实数据集中分析节点不同时刻的暂态中心性值发现,不同时刻节点的暂态中心性具有很强的相关性。基于此,提出几种预测方法对真实数据集中节点未来的暂态中心性值进行预测。通过对真实值与预测值进行误差分析,比较了不同预测方法在不同真实数据中的预测性能。结果表明,在MIT数据集中,最近时窗加权平均方法的性能最好;在Infocom 06数据集中,最近时窗平均方法的性能最好。     

基于无线传感网络的智慧农业监测系统设计

在信息化、智能化的时代背景下,智慧农业已成为推动农业现代化的重要手段。在这种情况下,基于无线传感网络的智慧农业监测系统应运而生,它融合了物联网、云计算、大数据等多项先进技术,为农业生产提供了全新的解决方案。文中介绍了智慧农业监测系统的研究背景,详细阐述了系统的总体设计、硬软件设计及数据分析方法,设计了一种基于无线传感网络的智慧农业监测系统,为农业生产提供了支持。     

A hyperbolic model for fluid–solids two-phase flow

A long unresolved problem in two-phase flow is that the inviscid form of a standard model is not hyperbolic, making initial-value problems based on the model ill-posed. In this paper we show that the model becomes hyperbolic when the buoyant force term in the model is modified to include the effect of relative motion between the phases. We also show that the new model gives physically realistic solutions for minimum fluidization, expansion of a tapered fluidized bed, and the flow of a neutrally buoyant mixture through a nozzle and compare the solutions with those of the standard model and an alternative model.     

Quantitatively comparing phase-field modeling with direct real time observation by synchrotron X-ray radiography of the initial transient during directional solidification of an Al-Cu alloy

The initial transient during directional solidification of an Al-4 wt.% Cu alloy was simulated by a quantitative phase-field model solved with the adaptive finite element method. The simulated solidification process was compared with the related analytical theory and in situ and real time observations by means of X-ray radiography at the European Synchrotron Radiation Facility. The simulated velocity of the planar interface and solute profile ahead of the solidification front in the liquid are close to the predictions of the Warren-Langer model of the initial planar solidification transient, but in fair quantitative agreement with experimental results only at early stages of planar solidification. After the accelerated flat interface lost its stability a transition to cellular solidification was initiated. The initial cell spacing predicted by the phase-field simulation agreed well with the experimental observations in the region where the cell growth direction was perpendicular to the fluid flow, whereas a discrepancy was obvious in the corners where the fluid flow was parallel to growth. An analytical relation describing the wavelength of the initial solid-liquid interface corrugations under diffusion-limited transport is screened out by comparing the phase-field simulation data with expressions based upon the Mullins-Sekerka linear stability analysis theory or derived for primary spacing. The gravity-driven natural convection in the experiment resulted in misfits between the phase-field predictions and the experimental observations in the late stage of planar solidification, onset and development of morphological instability.     

Optimal investment strategies in decentralized renewable power generation under uncertainty

This paper presents a method for evaluating investments in decentralized renewable power generation under price un certainty. The analysis is applicable for a client with an electricity load and a renewable resource that can be utilized for power generation. The investor has a deferrable opportunity to invest in one local power generating unit, with the objective to maximize the profits from the opportunity. Renewable electricity generation can serve local load when generation and load coincide in time, and surplus power can be exported to the grid. The problem is to find the price intervals and the capacity of the generator at which to invest. Results from a case with wind power generation for an office building suggests it is optimal to wait for higher prices than the net present value break-even price under price uncertainty, and that capacity choice can depend on the current market price and the price volatility. With low price volatility there can be more than one investment price interval for different units with intermediate waiting regions between them. High price volatility increases the value of the investment opportunity, and therefore makes it more attractive to postpone investment until larger units are profitable.     

The impact of Energy Performance Certificates on the rental and capital values of commercial property assets

This paper focuses on the effect of energy performance ratings on appraised capital values, rental values and equivalent yields of UK commercial property assets. The study is based on a cross-section of 708 commercial property assets. Incorporating a range of potential confounding factors such as unexpired lease term, vacancy rate and tenant credit risk, we use hedonic regression procedures to estimate the effect of EPC rating on rental and capital values. The study finds no evidence of a significant relationship between environmental and/or energy performance and rental and capital values. A small subset of 24 BREEAM-rated assets is also tested for significant price effects but a statistically significant effect is only confirmed for equivalent yields. Similarly, there was no evidence that the EPC rating had any effect on Market Rent or Market Value with only minor effects of EPC ratings on equivalent yields. The preliminary conclusion is that energy labelling is not yet having the effects on Market Values and Market Rents that would be expected if high EPC ratings were associated with substantial cost savings that are fully reflected in capital values and/or were readily available and taken into account by prospective tenants and buyers.