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61.
62.
Willem Potze 《Journal of Quantitative Spectroscopy & Radiative Transfer》2004,84(4):575-586
A mathematical model is proposed to describe the heat transfer in quartz glass axisymmetric tubes. Heat is transferred inside the glass by radiation and conduction. Scattering of thermal radiation inside the glass is ignored. At the boundaries of the tube the radiative intensity is specularly reflected. The spectral dependent radiative intensity and the temperature distribution inside the tube are determined. The model is applied to simulate the cooling process of a quartz glass tube. The calculated temperature is in agreement with that obtained from an experiment. Furthermore, steady-state temperature distributions in quartz glass tubes of different lengths have been determined. 相似文献
63.
D. Kaneko T. Narita J. P. Gong Y. Osada J. Ando K. Yamamoto S. Ohnishi V. V. Yaminsky 《Journal of Polymer Science.Polymer Physics》2003,41(22):2808-2815
The effect of the shear flow on the thickness change of a polyelectrolyte membrane grafted onto a glass substrate was directly investigated with a flow cell combined with a confocal laser scanning microscope. The membrane thickness decreased proportionally to an increase in the shear stress of the flow when the shear rate exceeded a critical value of 1 s?1. The higher the ionic strength was of the fluid, the greater the thinning effect was. The correlation between the critical shear rate and the relaxation of the polymer in the gel membrane was examined. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2808–2815, 2003 相似文献
64.
The quantum fluctuations of the stress tensor of a quantum field are discussed, as are the resulting space-time metric fluctuations. Passive quantum gravity is an approximation in which gravity is not directly quantized, but fluctuations of the space-time geometry are driven by stress tensor fluctuations. We discuss a decomposition of the stress tensor correlation function into three parts, and consider the physical implications of each part. The operational significance of metric fluctuations and the possible limits of validity of semiclassical gravity are discussed. 相似文献
65.
The noise of hybrid soliton pulse source (HSPS) with linearly chirped Gaussian apodized fiber Bragg grating is analyzed by couple-mode equations including spontaneous emission noise when the HSPS is mode-locked. Relative intensity noise is calculated using numerical solutions of these equations. It is shown that transform limited pulses are generated over a wide tuning range around the fundamental mode-locking frequency with low spontaneous noise. However, a high noise level affects the operation of device, and therefore transform-limited pulses are not obtainable over a wide tuning range. It is also shown that noise is extremely sensitive to the RF and DC currents, linewidth enhancement factor, gain saturation parameter and spontaneous coupling factor. 相似文献
66.
M. Stenger S. Baumhoff J.-Y. Prieur J. Joffrin J.-P. Contour 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,2(2):177-182
We present measurements of the attenuation and phase velocity of surface acoustic waves in thin YBa2Cu3O films as a function of temperature, in magnetic fields up to 3.6 T applied parallel to the c-axis of the films. We have observed anomalies in both, the attenuation and the phase velocity in the vicinity of the superconducting
critical temperature which do not depend on the magnetic field. Possible origins of these anomalies, observed, to our knowledge,
for the first time in YBa2Cu3O thin films, are discussed and compared to bulk acoustic wave experiments. We present a kind of feedback technique for surface
acoustic waves which improves the sensitivity of this type of measurement. The actual sensitivity limits are mentioned.
Received: 7 August 1997 / Revised: 7 November 1997 / Accepted: 17 November 1997 相似文献
67.
Soft matter, like colloidal suspensions and surfactant gels, exhibit strong response to modest external perturbations. This
paper reviews our recent experiments on the nonlinear flow behaviour of surfactant worm-like micellar gels. A rich dynamic
behaviour exhibiting regular, quasi-periodic, intermittency and chaos is observed. In particular, we have shown experimentally
that the route to chaos is via Type-II intermittency in shear thinning worm-like micellar solution of cetyltrimethylammonium
tosylate where the strength of flow-concentration coupling is tuned by the addition of sodium chloride. A Poincaré first return
map of the time series and the probability distribution of laminar length between burst events show that our data are consistent
with Type-II intermittency. The existence of a ‘Butterfly’ intensity pattern in small angle light scattering (SALS) measurements
performed simultaneously with the rheological measurements confirms the coupling of flow to concentration fluctuations in
the system under study. The scattered depolarised intensity in SALS, sensitive to orientational order fluctuations, shows
the same time-dependence (like intermittency) as that of shear stress. 相似文献
68.
The paper presents a theoretical-numerical hybrid method for determining the stresses distribution in composite laminates
containing a circular hole and subjected to uniaxial tensile loading. The method is based upon an appropriate corrective function
allowing a simple and rapid evaluation of stress distributions in a generic plate of finite width with a hole based on the
theoretical stresses distribution in an infinite plate with the same hole geometry and material. In order to verify the accuracy
of the method proposed, various numerical and experimental tests have been performed by considering different laminate lay-ups;
in particular, the experimental results have shown that a combined use of the method proposed and the well-know point-stress
criterion leads to reliable strength predictions for GFRP or CFRP laminates with a circular hole.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 43, No. 4, pp. 531–570, July–August, 2007. 相似文献
69.
郭冰 柳卫平 Trinczek M Lapi S Ames F Buckley K R D’Auria J M Jayamanna K Ruiz C Ruth T J 《中国物理 C》2006,30(7):675-679
加拿大TRIUMF实验室利用11C成功验证了一种产生高强度(~108ions/s)放射性束流的方法. 该方法不同于普通在线同位素分离方法, 它利用了13MeV的低能强流质子束, 可以产生一系列核天体物理实验感兴趣的高强度放射性束流. 相似文献
70.
A Jayanth Kumar N M Gowri R Venkateswara Raju G Nirmala B S Bellubbi T Radha Krishna 《Pramana》2006,67(2):383-387
Over the last two decades, the fiber optic technology has passed through many analytical stages. Some commercially available
fiber optic sensors, though in a small way, are being used for automation in mechanical and industrial environments. They
are also used for instrumentation and controls.
In the present work, an intensity-modulated intrinsic fiber optic sugar sensor is presented. This type of sensor, with slight
modification, can be used for on-line determination of the concentration of sugar content in sugarcane juice in sugar industry.
In the present set-up, a plastic fiber made of polymethylmethacrylate is used. A portion of the cladding (1 cm, 2 cm, 3 cm)
at the mid-point along the length of the fiber is removed. This portion is immersed in sugar solution of known concentration
and refractive index. At one end of the fiber an 850 nm source is used and at the other end a power meter is connected. By
varying the concentration of sugar solution, the output power is noted. These studies are made due to the change in refractive
index of the fluid. The device was found to be very sensitive which is free from EMI and shock hazards, stable and repeatable
and they can be remotely interfaced with a computer to give on-line measurements and thus become useful for application in
sugar industries. 相似文献