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排序方式: 共有525条查询结果,搜索用时 15 毫秒
61.
Dr. Th. Weller 《Computing》1975,14(3):271-284
Load-sharing computer networks require the portability of command languages. This can be achieved by the standardization or by the translation of command languages. The structure and the way of acting of a command language translator is given which is suitable for the translation of a specific class of command programs and which consists of a languageindependent program working on language dependent tables. An example is given for the translation of a command program. 相似文献
62.
Cross-linking in bituminous coals has been studied by internal friction methods. A low temperature damping peak occurring at 130 K for a frequency of 1 Hz has been used to deduce the character of cross-linking in coal. The molecular units responsible for the internal friction are found to be methylene chains connecting ring structures of the macromolecular material. The number varies progressively from a Braunkohle with 67wt% carbon to anthracites of > 90 wt% carbon. The number goes through a maximum at ≈80 wt%C, showing that the cross-link density reaches a maximum at that carbon level. It falls of markedly at higher carbon concentrations and remains at a low level > 85 wt%C. These findings correlate well with models of coal structure. 相似文献
63.
This review on menstrual synchrony in human females has four purposes: (a) to determine whether or not the phenomenon exists, and whether it differs in the various groups studied: roommates in dormitories, roommates in private residences, close friends, work groups, mothers-daughters; (b) to assess the magnitude of its effect, i.e., to what extent does the single factor of living together affect menstrual synchrony?; (c) to examine the effects of menstrual-related factors, social interaction factors, and personality on menstrual synchrony; (d) to assess whether the findings support a pheromonal or common environmental explanation of menstrual synchrony. Several methodological issues are also discussed. 相似文献
64.
In Aplysia fasciata, the sea hare, shock paired with moderate increases or decreases in the seawater concentration leads to pairing-specific increases in the respiratory pump rate in response to the same solutions an hour later. A common neural circuit underlies learned changes to increased and decreased seawater concentration, as shown by complete generalization of learning between these stimuli. Different neural circuitry controls learning after pairing a shock with pH 7 seawater, as shown by a lack of generalization of learning to this stimulus. Preexposure to strong changes in the seawater leads to sensitization of respiratory pumping. The hypothesis was tested that associative learning and sensitization arise from activation of common pathways. However, patterns of generalization of sensitization elicited by preexposure to altered seawaters differ from those produced by associative learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
65.
Finite element modelling of impact on preloaded composite panels 总被引:1,自引:0,他引:1
K.M. Mikkor R.S. Thomson I. Herszberg T. Weller A.P. Mouritz 《Composite Structures》2006,75(1-4):501-513
Composite aircraft structures are susceptible to impact damage during manufacture, maintenance and in-flight. Low energy impact damage is often internal and invisible, but can significantly reduce the stiffness and strength or cause catastrophic failure when the structure is under load during the impact event. This paper describes the development and application of an explicit finite element (FE) model, incorporating a bi-phase material degradation model, to predict the behaviour of loaded carbon/epoxy panels when impacted over a range of low energy levels. Overall, the trends predicted in the FE simulations were consistent with experimental data, although quantitatively the FE results were generally conservative. However, the model greatly underestimated the catastrophic failure boundary. The model was used to investigate the effect of various parameters including magnitude of preload, impact velocity and specimen geometry on the amount of damage and the residual strength of carbon/epoxy panels. 相似文献
66.
F A Adriaens M A Miller D L Hard R F Weller M D Hale R J Collier 《Journal of dairy science》1992,75(2):472-480
The effect of sometribove (USAN, methionyl bST) on the endocrine pancreas and blood bST concentrations was investigated in 6 control and 6 treated Friesian cows, averaging 111 and 118 d postpartum in their fourth lactation of treatment. Each lactation the treated cows received sometribove injections (500 mg) every 2 wk (injection cycle) starting 60 +/- 3 d postpartum, increasing milk yield 3.3, 5.9, 1.9, and 4.2 kg/d in lactations 1, 2, 3, and 4, respectively. On d 8 of a fourth lactation injection cycle, blood was sampled for 390 min, starting 30 min before an intravenous glucose infusion (100 mg/kg) over a 20-min period. Preinfusion concentrations of glucose, insulin, and bST were elevated in sometribove-treated cows versus controls: 82.1 versus 74.4 mg/dl, 28.1 versus 19.7 microIU/ml, and 4.6 versus .9 ng/ml, respectively. Glucose infusion resulted in a rapid increase in blood glucose and insulin concentrations, followed by a sharp decline to preinfusion values across both treatments, resulting in similar net area under the curves for glucose and insulin. Blood bST concentrations remained unchanged. This study supports the concept that sometribove increases milk yield in dairy cows by chronically influencing homeorhetic mechanisms. 相似文献
67.
The extent of coal hydroliquefaction in the presence of a good catalyst (impregnated ammonium heptamolybdate) and a hydrogen-donor solvent (tetralin) can be substantially greater in a tubing bomb than in a stirred autoclave, under nominally identical liquefaction conditions. This difference may be associated with the typically lower gas:liquid volume ratio existing under reaction conditions in a tubing bomb, relative to the ratio in an autoclave. If equilibrium is reached in the catalysed dissociation of tetralin, the extent of dissociation is less, and the hydrogen partial pressure is substantially higher, in the tubing bomb than in the autoclave. Calculations and measurements have been made for the equilibrium conditions in tetralin dissociation when coal is absent but a good catalyst (ammonium heptamolybdate dispersed on alumina) is present. For the calculation, the molar volumes and vapour pressures of tetralin and naphthalene must be known, together with the dissociation constant. Agreement was good between calculated and experimental values of dissociation in both tubing bomb and autoclave. The results permit prediction that increasing the gas:liquid volume in a tubing bomb liquefaction experiment should decrease the conversion; this effect was observed. 相似文献
68.
AM Dvorak PF Weller VS Harvey ES Morgan HF Dvorak 《Canadian Metallurgical Quarterly》1993,101(2):136-142
The majority of equations used to predict values for basal metabolic rates (BMRs) are the result of indirect calorimetry measurements performed in the 1930s and 1950s. To assess the reliability of these equations in predicting the resting energy expenditure (REE) of the children in our community, indirect calorimetry was performed on 92 male and 107 female healthy children 2-3 h postprandial. Each individual was measured for a duration of 15-20 min. The data for analysis were obtained from 5-15 min steady-state periods. Subjects ranged in age from 5 to 16 years. The results were compared with BMRs calculated from the Harris-Benedict equation (Harris J, Benedict F. A biometric study of basal metabolism in man. Washington, DC: Carnegie Institute of Washington, publication no. 279, 1919.), the Food and Agriculture Organization/World Health Organization/United Nations University (FAO/WHO/UNU) equations, and the equations proposed by Schofield for use by the 1985 FAO/WHO/UNU Nutrition Committee. The values predicted by the FAO/WHO/UNU and Schofield equations were consistent with the measured resting values for all the children in the study population. Ninety-two children weighed between 90-110% of their ideal body weight. When the measured REE and estimated BMR were compared by gender and age in these children, the Schofield equations provided the best estimates. Ninety-four of the study subjects weighed > 110% of their ideal body weight. The predicted estimates by all equations were consistent with the measured values in this subgroup of the population. We conclude that the FAO/WHO/UNU and Schofield equations are reliable estimates of metabolic rate in healthy children when measurement of REE is not possible. 相似文献
69.
A new method of time-frequency analysis, based on the Matching Pursuit (MP) algorithm, was used to extract and quantify EEG 'driving' or frequency-following responses produced in human primary somatosensory cortex (SI) by 33 Hz vibrotactile stimulation of the right index fingertip in a single subject. EEG signals were recorded from a 5 x 5 array of electrodes centered over the left hand area, time-locked to repeated presentations of four vibratory stimulus amplitudes. The MP algorithm was used to decompose the edited and and filtered EEG signals into waveforms selected from a large and redundant dictionary. Statistical discrimination of the vibratory stimulus amplitudes was then readily achieved in terms of trial-by-trial measures of response amplitude constructed in automated fashion from the calculated MP parameters. The results were orderly and physiologically coherent, and potentially open the way to correlation of psychophysical magnitude estimates with measures of neurophysiological response on a trial-by-trial basis. The approach developed here appears well suited to detection and characterisation of time dependent or transient target signals embedded in a noisy background. 相似文献
70.