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101.
One of the standard methods of simplifying the task of obtaining a shaded image of a solid object is to represent it by a polyhedron. Another method is to use sculptured surface modelling which represents surfaces by collections of surface patches. Using either method the surfaces can be approximated by facets, which are simple to shade according to photometry information.
To obtain a smooth image in regions of high curvature, the surface would typically be required to have hundreds or thousands of facets. Because of the large number of facets involved, it is extremely important that geometrical and topological information is stored in an efficient manner. This information must include all that is required for an unambiguous representation of the solid(s) in question.
The compressed data structure (CDS) is suitable for this purpose, and is capable of defining the majority of surfaces. The structure is intended to minimise the amount of data stored, with as much information as possible being implied. The CDS can be easily generated knowing the order of the vertices defining the surface.  相似文献   
102.
Flexible monitoring helped to establish an intermediate care unit, close an intensive care unit (ICU) and reduce cost by decreasing length of stay (LOS) and matching patients to appropriate care. These efforts saved the hospital $3,260,215 over the first year while maintaining positive patient outcomes.  相似文献   
103.
Tested 18 males and 18 females from each of 2 age groups (mean ages, 37 and 53 mo) on a recognition test under each of 3 conditions: (a) verbal only, (b) visual only, and (c) verbal-visual. Correct recognition was obtained for all Ss. Older Ss, however, performed significantly better than younger. Neither age group benefited from E-provided labels; performance in the visual-only and visual-verbal conditions was comparable. It is concluded that the development of mechanisms other than verbal mediator production must account for any age-related improvement in recognition performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
104.
In determining the reproducibility of Tg data of a standard polystyrene measured by differential scanning calorimetry (d.s.c.), the effects of d.s.c. trace interpretation method, extrapolation to zero scan rate, polymer sample form, a thermal treatment and a thermal cycling procedure on the results were examined. The results showed that data from scanning at 8°C/min are preferred to those from extrapolation to zero scan rate while the overall reproducibility was unaffected by the d.s.c. trace interpretation method used. However, the onset of the transition step was selected to define Tg in this work. Similarly, no differences in the reproducibility of data were noted between the overall results for granular or sheet samples, although certain treatments of specific samples did produce changes in some instances. The mean value for Tg at 8°C/min was found to be 102.3°C. Imposing the thermal treatment on the samples did not significantly alter the reproducibility of the results whereas in contrast, cycling markedly improved the reproducibility of sheet sample data but left that of granules unaffected.  相似文献   
105.
Scanner design     
The scanner is a subroutine which is frequently called by an application program like a compiler. The primary function of a scanner is to combine characters from the input stream into recognizable units called tokens. A method has been presented in this paper for designing such a scanner, also frequently referred to as a lexical analyser in the current literature. The major steps involved in this design process are: identification of tokens, construction of a state diagram, building driver tables and finally writing a scanning routine. The rules for generating the driver tables are described and an algorithm for the scanner, utilizing these driver tables, is included. The method has been successfully used to build the system scanner for a user oriented plotting language. It is concluded that the method is well defined, gives rise to a modular design and as such easily lends itself to language extensions.  相似文献   
106.
Conducted 3 experiments to examine the effects of picture cues and exhaustive search on very young children's memory for the location of hidden objects. In Exp I, 64 2-yr-olds' performance was examined with control and exhaustive search procedures in spatial-only and spatial- and picture-cue conditions. In Exp II, 32 2-yr-olds' performance with the same 2 search procedures was examined in a cue condition that eliminated spatial information. In Exp III, 64 2- and 3-yr-olds' performance with the control and exhaustive search procedures was examined in 2 array conditions that also eliminated spatial information. All experiments confirmed that even 2-yr-olds use picture cues to encode and search for the location of hidden objects. It was also found that while 2-yr-olds' delayed response performance was improved by exhaustive search procedures, this was not true for 3-yr-olds. Apparently, more complete search strategies contribute to the developmental change in young children's localization performance. (10 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
107.
We have designed and demonstrated a standoff Raman system for detecting high explosive materials at distances up to 50 meters in ambient light conditions. In the system, light is collected using an 8-in. Schmidt-Cassegrain telescope fiber-coupled to an f/1.8 spectrograph with a gated intensified charge-coupled device (ICCD) detector. A frequency-doubled Nd : YAG (532 nm) pulsed (10 Hz) laser is used as the excitation source for measuring remote spectra of samples containing up to 8% explosive materials. The explosives RDX, TNT, and PETN as well as nitrate- and chlorate-containing materials were used to evaluate the performance of the system with samples placed at distances of 27 and 50 meters. Laser power studies were performed to determine the effects of laser heating and photodegradation on the samples. Raman signal levels were found to increase linearly with increasing laser energy up to approximately 3 x 10(6) W/cm2 for all samples except TNT, which showed some evidence of photo- or thermal degradation at higher laser power densities. Detector gate width studies showed that Raman spectra could be acquired in high levels of ambient light using a 10 microsecond gate width.  相似文献   
108.
Predicting fatigue crack growth in metals remains a difficult task because available models are based on cycle-derivative equations, such as the Paris law, while service loads are often far from being cyclic. The main objective of this paper is therefore to propose a set of time-derivative equations for fatigue crack growth. The model is based on the thermodynamics of dissipative processes. For this purpose, three global state variables are introduced in order to characterize the state of the crackthe crack length a, the plastic blunting at crack tip and the intensity of crack opening C. Thermodynamics counterparts are introduced for each variable. Special attention is paid to the elastic energy stored inside the crack tip plastic zone, because, in practice, residual stresses at crack tip are known to considerably influence fatigue crack growth. The stored energy is included in the energy balance equation, and this leads to the appearance of a kinematics hardening term in the yield criterion for the cracked structure. No dissipation is associated with crack opening, but to crack growth and to crack tip blunting. Finally, the model consists in two laws: a crack propagation law, which is a relationship between d dt and da/dt and which observes the inequality stemmed from the second principle, and an elastic-plastic constitutive behaviour for the cracked structure, which provides d dt versus applied-load. The model was implemented and tested. It reproduces successfully the main features of fatigue crack growth as reported in the literature, such as the Paris law, the stress-ratio effect and the overload retardation effect.  相似文献   
109.
681 usable questionnaire returns were received from PhD psychologist respondents. Since completing the language requirements 65% or almost ? of the cases had not read a single item (article or book). "The median number of items read in French, German, Spanish, and Russian was 0." 70% made no oral use of the languages. There is an "extreme incongruity between input and output" in the study of foreign languages at the PhD level. Alternative solutions are proposed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
110.
The thermodynamic pK value of picric acid was determined spectrophotometrically in water containing hydrochloric acid to repress the ionization. The pK value 0.33 (K ≈ 0.46) was obtained from data at 450 mμ. Attempts to determine the pK value by potentiometric titrations of picric acid and by spectrophotometric measurements of picric acid solutions in the near-saturation range did not yield satisfactory results. The new pK value is compared with previously published values.  相似文献   
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