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61.
62.
In this work, we present the Damped and Delayed Sinusoidal (DDS) model: a generalization of the sinusoidal model. This model takes into account an angular frequency, a damping factor, a phase, an amplitude, and a time-delay parameter for each component. Two algorithms are introduced for the DDS parameter estimation using a subband processing approach. Finally, we derive the Crame/spl acute/r-Rao Bound (CRB) expression for the DDS model and a simulation-based performance analysis in the context of a noisy fast time-varying synthetic signal and in the audio transient signal modeling context. 相似文献
63.
PR Burchat GJ Feldman T Barklow AM Boyarski DL Burke JM Dorfan L Gladney G Hanson K Hayes RJ Hollebeek WR Innes JA Jaros D Karlen AJ Lankford RR Larsen BW LeClaire NS Lockyer V Lüth C Matteuzzi RA Ong ML Perl B Richter K Riles MC Ross JM Yelton C Zaiser GS Abrams D Amidei AR Baden J Boyer F Butler G Gidal MS Gold G Goldhaber L Golding J Haggerty D Herrup I Juricic JA Kadyk ME Nelson PC Rowson H Schellman WB Schmidke PD Sheldon GH Trilling de la Vaissiere C DR Wood ME Levi T Schaad 《Canadian Metallurgical Quarterly》1987,35(1):27-41
64.
Beta alloys, such as Ti-10V-2Fe-3Al, can be processed and heat treated to provide a wide range in mechanical and fracture
properties. A systematic study of the effect of processing and heat treatment variations on the properties combinations achievable
was undertaken. The ductility and fracture toughness can be very significantly influenced by processing and heat treatment
variations. The ductility increases and the toughness decreases as the morphology of the primary alpha changes from acicular
to equiaxed. This morphology change was caused by alterations in forging procedures. Reducing the strength increases both
fracture toughness and ductility. Microstructure has only a minor influence on fatigue performance in the high strength (about
1310 MPa UTS) condition. The micro-structure does, however, have a significant effect on fatigue behavior in a low strength,
about 1034 MPa UTS, condition. More lamellar alpha results in improved notched fatigue performance, while a more equiaxed
alpha improves smooth fatigue performance. These changes in properties are rationalized in terms of microstructure. 相似文献
65.
Aloe‐vera‐incorporated polycaprolactone nanofibrous matrixes were prepared by an electrospinning method. These developed matrixes were evaluated for their water absorption capacity, water vapor permeability, and contact angle, and, in an in vivo animal model, wound‐healing ability. The incorporation of the herbal drug made the matrixes hydrophilic with improved water retention and permeability properties. The in vivo studies were carried out in a rat model and showed improved results with respect to healing. Thus, this study confirmed that the developed matrixes could be used for wound‐healing applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42178. 相似文献
66.
Simple models based on the physical and biochemical processes occurring in septic tanks, pit and urine diversion latrines were developed to determine the nutrient flows in these systems. Nitrogen and phosphorus separation in different output materials from these on-site sanitation installations were thus determined. Moreover, nutrient separation in septic tanks was also assessed through literature values and by eliciting expert judgement. Use of formal expert elicitation technique proved to be effective, particularly in the context of developing countries where data is often scarce but expert judgement readily available. In Vietnam, only 5-14% and 11-27% of the nitrogen and phosphorus input, respectively, are removed from septic tanks with the faecal sludge. The remaining fraction leaves the tank via the liquid effluent. Unlike septic tanks, urine diversion latrines allow to immobilize most of the nutrients either in form of stored urine or dehydrated faecal matter. These latrines thus contribute to reducing the nutrient load in the environment and lowering consumption of energy and non-renewable resources for fertiliser production. 相似文献
67.
68.
Agnes Verweij 《Nexus Network Journal》2010,12(1):47-62
Perspective is an optional subject for students of some levels in Dutch secondary schools. A proper final task on this subject
is the analysis of existing perspective drawings or paintings. This task is sometimes supplemented by a more creative and
challenging assignment, that is, the design and construction of a perspective box. A perspective box is an empty box with,
on the inner sides, perspective pictures giving a surprising spatial effect when observed through the peephole. The students
who take up the challenge are in the first place inspired by the six still existing antique wooden perspective boxes, especially
because they were created by Dutch seventeenth-century painters of architecture and interiors. In this article the setup of
the perspective in these boxes will be discussed. But for a clear comprehension, we begin by reviewing the principles of linear
perspective and their implications for the way perspective images can best be viewed. 相似文献
69.
This paper presents initial values of global and diffuse luminous efficacy at Saint-Pierre (Reunion Island). Firstly, data used were measured for a period of 6 months, from February to June 2008. During this period, all defined day-types have been studied (clear, cloudy and intermediate). Generally, the meteorological database of Reunion does not contain information for illuminance values. On the other hand, the local meteorological center has a 60-years-old database for solar irradiance (W/m2). So it is important to determine Luminous Efficacy in order to find illuminance from solar irradiance (or luminance from solar radiance). The measured data were analyzed, and empirical constant models were developed and presented in this paper in order to determine luminous efficacy under different sky conditions. A comparison between these empirical constants (models) and existing models has been made. The method used to define sky conditions (overcast, intermediate and clear) and day-types characterization as well as classification will be presented in this work. 相似文献
70.