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101.
Nylon 66(ICI Polyamide 66, Carded & Combed Top) fibers were annealed in the temperature range 80–180°C for 1–10 h. Refractive indices and birefringence were measured interfer-ometrically. Two independent techniques were used to study the optical anisotropy in these fibers. The first technique was to study the effect of annealing on the swelling properties of fibers from its diffraction pattern using a He—Ne laser beam. The second was the application of multiple-beam Fizeau fringes in transmission to determine the skin and core refractive indices and double refraction of annealing samples. The application was carried out using multiple-beam Fizeau fringes in transmission to determine Cauchy's constants and the dispersive coefficient for the fiber layers. The resulting data were used to calculate the mean polarizability per unit volume and the isotropic refractive indices. Behavior of optical properties at different annealing conditions is discussed. The results obtained clarify the new reorientation, and each layer change occurred due to annealing at different conditions. Microinterferograms and curves are given for illustration. © 1996 John Wiley & Sons, Inc. 相似文献
102.
Mohammad Javad Nasr Isfahani Parisa Nasr IsfahaniKlebson Lucenildo Da Silva Armin FeldhoffVladimir Šepelák 《Ceramics International》2011,37(6):1905-1909
NiFe2−xBixO4 (x = 0, 0.1, 0.15) nanopowders were synthesized via sol-gel method. The precursor gels were calcined at 773 K in air for 1 h to obtain the pure nanostructured NiFe2−xBixO4 spinel phase. The crystal structure and magnetic properties of the substituted spinel series of NiFe2−xBixO4 have been investigated by means of 57Fe Mössbauer spectroscopy, transmission electron microscopy and alternating gradient force magnetometry. Mössbauer spectroscopic measurements revealed that Bi3+ cations tend to occupy octahedral positions in the structure of the substituted ferrite, i.e., the crystal-chemical formula of the as-prepared nanoparticles may be written as: (Fe)[NiFe1−xBix]O4 (x = 0, 0.1, 0.15), where parentheses and square brackets enclose cations on sites of tetrahedral and octahedral coordination, respectively. Selective area electron diffraction studies provided evidence that the samples of the NiFe2−xBixO4 series, independently of x, exhibit the cubic spinel structure. The values of the saturation magnetization and the coercive field of NiFe2−xBixO4 nanoparticles were found to decrease with increasing degree of bismuth substitution. 相似文献
103.
The paper focuses on the performance of quantum-wire infrared photodetectors (QRIPs) under dark condition. The effects of the average quantum wire density, the lateral size and the operating temperature on the behaviour of this device are studied. The superiority of QRIPs over the quantum-dot infrared photodetectors (QDIPs), which give lower and stable increasing dark current, is illustrated clearly. A distinct improvement of the responsivity and detectivity of QRIPs compared to QDIPs has been perceived. The theoretical analysis confirms that the stability of QRIPs is affected by the operating temperature. 相似文献
104.
105.
JG Ouslander SZ Nasr M Miller W Withington CS Lee M Wiltshire-Clement P Cruise JF Schnelle 《Canadian Metallurgical Quarterly》1998,46(10):1274-1279
OBJECTIVES: To examine the relationship between diurnal urine volume and plasma arginine vasopressin levels (AVP) in nursing home residents with nighttime urinary incontinence and a comparison group of frail but nondemented, continent geriatric board and care residents. DESIGN: Case series. SETTING: Four nursing homes and two board and care facilities. PARTICIPANTS: Sixty-two nursing home residents and 27 board and care residents. MEASUREMENTS: Daytime (7:00 a.m. to 7:00 p.m.) and nighttime (7:00 p.m. to 7:00 a.m.) urine volumes of incontinent nursing home residents were measured over 3 days and 3 nights by reweighing preweighed adults diapers and toileting inserts emptied by research staff for the comparison group. AVP levels were drawn in the early morning (5:00 a.m. to 7:00 a.m.) before subjects arose and in the evening after an hour of lying in bed (8:00 p.m. to 11:00 p.m.), and plasma levels were determined by radioimmunoassay. RESULTS: Half of the nursing home residents and 82% of the comparison group had night/total urine volume ratios > or = 50%. Forty-nine percent of the total of 89 subjects had undetectable morning AVP levels, 61% had undetectable evening AVP levels, and 42% had undetectable AVP levels in both morning and evening. There were no significant differences in AVP levels between those with night/total urine volume ratios > or = 50% and < 50% in either the nursing home or comparison groups though the small number of comparison group subjects with ratios < 50% may have limited our statistical power to detect differences. CONCLUSION: Our data suggest that a substantial proportion of both nursing home residents with nighttime incontinence and frail geriatric patients with a reversal of the normal diurnal pattern of urine excretion have an accompanying deficiency in AVP production and/or secretion. More detailed physiologic studies are needed to understand better the pathophysiology of geriatric nocturia and nighttime incontinence and the role that AVP deficiency may play in these conditions. Until such studies are carried out, we do not recommend the routine use of exogenous AVP for geriatric patients with unexplained nocturnal polyuria. 相似文献
106.
SJ Nasr 《Canadian Metallurgical Quarterly》1976,33(10):1202-1203
Several authors have attempted to establish a correlation between glucose-6-phosphate dehydrogenase (G-6-PD) deficiency and chronic schizophrenia, and the results were contradictory. We propose that the correlation between G-6-PD deficiency and schizophrenia is to be found in the form of an acute delirium. 相似文献
107.
“Shell-and-tube heat exchanger with helical baffles” is one of the new technologies used to improve the performance of common heat exchangers with segmental baffles. In this paper, after a short introduction of the technology, investigations of fluid flow pattern are carried out. By creating different arrangements of the helical baffles, the comparison between these types of baffles and the segmental one has been performed. Then, by using derived pressure drop relationship and the rapid design algorithm, some equations for both turbulent and laminar regimes are developed which relate pressure drop to heat transfer coefficient and heat transfer area. With the help of these relationships a straightforward design procedure has been developed. 相似文献
108.
Experimental and Numerical Simulation of Dry Pressure Drop in High‐Capacity Structured Packings
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Experimental and numerical studies were conducted on the performance and capacity of structured packings for mixture separation with very low separation factor. Different formations and conditions of the innovative structured packing PACK‐2100 with high surface area were studied to evaluate the main characteristics such as dry pressure drop. In addition, numerical simulation was performed to describe the details of the flow structure in these modified structured packings. Three‐dimensional computational fluid dynamics modeling of PACK‐2100 allowed for comparing the pressure drop in both laminar and turbulent flow regime. The obtained experimental and numerical data demonstrate the potential contribution of the packing to high‐efficiency systems with low separation factor. 相似文献
109.
110.
Delecraz Sebastien Becerra-Bonache Leonor Favre Benoit Nasr Alexis Bechet Frederic 《Neural Processing Letters》2021,53(5):3095-3121
Neural Processing Letters - Although documents are increasingly multimodal, their automatic processing is often monomodal. In particular, natural language processing tasks are typically performed... 相似文献