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A proposed method to reconstruct the three‐dimensional dispersion profile of polymeric fibres based on variable wavelength interferometry 下载免费PDF全文
In this paper, we suggest a modification to the conventional variable wavelength interferometry. This modification allowed us to calculate the dispersion curve of each point inside polymeric fibres instead of calculating the mean dispersion of these fibres. This modified mathematical treatment was used to calculate the three‐dimensional dispersion profile of isotactic polypropylene fibres suffering from necking deformation. The different steps of calculating the three‐dimensional dispersion profile of the fibre were demonstrated. The application of this modified method revealed the variation of the fibre material dispersion before, inside and after the necking region. In addition, the birefringence profile of the necked isotactic polypropylene was determined using the proposed mathematical treatment. This allowed us to diagnose the interaction of the incident waves with necked polypropylene fibres, which gives extensive information on the orientation of the molecular chains during the formation of the necking phenomenon. 相似文献
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Stuffed grape vine leaves, dolma is a well-liked Turkish dish, common to Mediterranean diets. Moisture, ash, energy, protein, fat, carbohydrate, calcium, sodium, iron, β-carotene (vitamin A), vitamin C analyses were conducted to determine the nutritional value of dolma. β-carotene level per 100 g serving of dolma (1041 IU) supplies 20.82% of the USRDA (5000 IU) and an INQ (Index of Nutritional Quality) for vitamin A of 2.54. Although the fat content and INQ for fat were found to be high in dolma, it can still be considered a healthy choice due to the type of oil used, namely olive oil, which has been shown to have beneficial effects on health. 相似文献
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This paper introduces a double‐image multiple‐beam Fizeau fringes system. The introduced system can dynamically determine the variations of the refractive indices for both parallel and perpendicular polarization simultaneously. This is achieved by the simultaneous capturing of two multiple‐beam interference patterns during the mechanical processing of isotactic polypropylene fibre. This parallel determination of the refractive indices of both polarization directions allowed us to determine the full‐field distribution of the stress vector, S . To accomplish this, a mathematical model was deduced to calculate the components of the stress vector, S , i.e. parallel stress component, S1, and perpendicular stress component, S2. Double‐image Fizeau fringes system and the deduced mathematical model were used to investigate the variation of the refractive index and stress components of the fibre during the stretching process and propagation of necked regions. 相似文献
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In typing, when the fingers executing two successive movements are on the same hand, the time between keystrokes is longer than when the fingers are on different hands. Biomechanical limitations of the hands are thought to account for this difference. The generality of this finding was explored by investigating skilled pianists' performance of two successive notes. Experiment 1 failed to find comparable differences in timing as a function of the hands involved. Experiment 2, employing both a piano production and a typing task, replicated the previous piano performance results, and revealed that the timing differences in typing were limited to letter sequences requiring fore-aft and lateral finger movements. Experiment 3 extended this finding to piano performance. Together, these findings clarify the nature of biomechanical constraints on skilled manual performance. 相似文献
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BI Reiner EL Siegel KJ French RS Dentry WT Mazan MJ Maroney 《Canadian Metallurgical Quarterly》1997,17(6):1487-1495
The authors demonstrate the use of radiography in the investigation of an historic painting and describe the potential benefits of computed radiography compared with conventional screen-film radiography. The subject for the comparison was a 16 x 19-foot oil-on-canvas painting, Scipio Africanus Freeing Massiva, by Giovanni Battista Tiepolo. Radiographs of the painting were obtained by using a portable, industrial radiographic unit and both conventional screen-film and photostimulable phosphor plate cassettes. For this investigation, computed radiography had a number of advantages over screen-film radiography, largely due to its wider dynamic range and its capabilities for enhancing the digital images with image processing tools such as magnification, edge enhancement, colorization, and airbrushing. The ability to electronically combine images from the large painting into a single composite image file was extremely valuable, as this technique was much less cumbersome and resulted in much higher quality composite images than could be achieved with conventional radiography. An additional advantage of computed radiography includes the capability to easily archive and transmit these images in a digital format for subsequent review. 相似文献
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EL Code CL Crespi BW Penman FJ Gonzalez TK Chang DJ Waxman 《Canadian Metallurgical Quarterly》1997,25(8):985-993
In situ hybridization was combined with serotonin (5-hydroxytryptamine, 5-HT) or tyrosine hydroxylase immunocytochemistry and with Fluoro-Gold retrograde labeling of bulbo-spinal pathways in order to investigate the expression of GAP-43 mRNA in monoamine cell groups of the adult rat brain stem. Consistent with previous reports, GAP-43 mRNA was observed in serotonin and dopamine cell groups in the pons. In addition, GAP-43 expressing cells were observed in all the major monoamine cell groups in the medulla. Thus the B1, B2 and B3 serotonin cell groups all showed high GAP-43 expression in all contained many GAP-43 expressing serotonin cells with spinal cord projections. The A1, A2, A5 and A6 noradrenaline cell groups also showed high GAP-43 expression, although cells with spinal cord projections were largely restricted to the A5 group and A6 subcoeruleus region. In all areas, GAP-43 expressing cells with spinal cord projections were also observed which were not serotonergic or noradrenergic. 相似文献
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Earlier studies have shown that a single, millisecond duration pulse of ultrasound delivered to the frog heart in vivo during systole can produce a reduction in the developed aortic pressure, while a pulse delivered during diastole can produce a premature ventricular contraction. The threshold for these effects is 5-10 MPa with a 5-ms pulse. Since cardiac tissues respond to mechanical stimulation, the objective of this study was to investigate acoustic radiation force as a possible mechanism for the observed effects of ultrasound on the frog heart. In two experiments, the radiation force exerted on the heart was varied by varying the ultrasonic frequency and the acoustic beam width. Results of these studies indicated that the rate of occurrence of the reduced aortic pressure effect was directly correlated with the magnitude of the radiation force exerted on the heart. A third experiment tested the radiation force mechanism directly by placing an acoustic reflector on the frog heart. The acoustic reflector maximized the radiation force delivered to the heart, but eliminated direct interaction of the ultrasound with the heart and experimentally eliminated heating and cavitation as mechanisms of action. The reduced aortic pressure effect was observed with the reflector on the heart, indicating that radiation force is capable of producing this effect. No premature ventricular contractions were observed with the acoustic reflector over the heart, suggesting that another property of the exposure may be responsible for this bioeffect. 相似文献