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71.
CW-diode laser crystallization of amorphous silicon (a-Si) deposited by sputtering or by electron beam evaporation onto different substrates (glass without or with SiNx or SiO2 intermediate layers) is investigated. The resulting grain sizes and orientations are characterized by electron backscatter diffraction, optical microscopy, and x-ray diffraction. We demonstrate that 200 nm thick sputtered a-Si layers can be crystallized on all of the used substrates to result in grains from 1 up to 100 μm in size, depending on the laser irradiation parameters (intensity, exposure time). Electron beam evaporated a-Si films can be crystallized only on sputtered SiNx intermediate layers to result in grains of 100 μm in size. Similar crystallographic film properties follow from laser treatment if the product of laser peak intensity and square root of exposure time is kept constant, independent of the scan velocity used. A high fraction of preferred (100)-oriented silicon grains can only be observed for samples with crystallites less than 10 μm in size.  相似文献   
72.
Process-Identification at Plasma Spraying Thermally Sensitive Materials Using an Infra-red Thermal Imaging System Nowadays so called thermally sensitive materials are deposited by thermal spray techniques. Due to the high temperature process an undesired alteration (evaporation, chemical decomposition) of the material could occur. Therefore, optimisation of the deposition based only on empirical methods may be deremental with respect to the coating properties. This study shows the potential of an IR thermal imaging technique as a process control for evaluation and optimisation of the deposition through better understanding of the thermal spray process. The spray trials presented are based on preliminary examinations carried out with diagnostic tools. Therefore it was possible to achieve defined air plasma sprayed coatings of hydroxyapatite with different coating and component properties. This is particularly of interest, since there exists only a standard for hydroxyapatite as starting material but not for plasma sprayed coatings. Hence the coatings had either high or low contents of undesired phases, different degrees of cristallinity and bond strengths-varying from 5 to 42 MPa. Besides the power levels and the way to obtain the power the carrier gas flow significantly influences the properties of the coatings.  相似文献   
73.
BACKGROUND: Human studies have demonstrated that processing of tomato can greatly increase lycopene bioavailability. However, the difference between processing methods is not widely investigated. In the current study different thermal treatments of tomato were evaluated with regard to their impact on in vitro bioaccessibility and retention of lycopene and β‐carotene as well as textural properties. Thermal treatments used were low (60 °C) and high (90 °C) temperature blanching followed by boiling. RESULTS: Lycopene was relatively stable during thermal treatment, whereas β‐carotene was significantly (P < 0.05) reduced by all heat treatments except for low temperature blanching. In vitro bioaccessibility of lycopene was significantly increased from 5.1 ± 0.2 to 9.2 ± 1.8 and 9.7 ± 0.6 mg kg?1 for low and high temperature blanching, respectively. An additional boiling step after blanching did not further improve lycopene bioaccessibility for any treatment, but significantly reduced the consistency of low temperature treated samples. CONCLUSION: Choice and order of processing treatments can have a large impact on both lycopene bioavailability and texture of tomato products. Further investigations are needed, but this study provides one of the first steps towards tomato products tailored to optimise nutritional benefits. Copyright © 2010 Society of Chemical Industry  相似文献   
74.
The Use of Natural Binders in Paper Making and Surface Applications. Binders are used in paper making for improvement of web strength and in surface operations – here particularly in coating – for gluing the pigments applied to the paper surface onto the same. As „natural binders”︁ those are meant here, which are of plant or animal origin and which are used as solutions or colloidal solutions. That is a distinct boundary towards the synthetic dispersions, which dominate the field today. Starch excels in economic importance among the natural binders. In order to strengthen the web structure cationic starches are used in the furnish. By the help of a size press the surface improvement of the paper can be done within the paper machine. Here native and degraded starches are predominant. In the case of paper coating fine pigment particles are applied to the paper surface in order to obtain a smoother paper surface with improved printability. The pigments must be held to the paper by a binder. Even as the use of starch for this purpose of pure binding power is more economic in comparison to synthetic latices, they are nevertheless here dominant. The reason for this are problems, which show up in printability of coated starch containing paper surfaces. They are reduced ink reception and migration of starch during drying of the coatings. It should be possible that in cooperation between the paper and the starch industry existing problems in the use of starch can be solved or diminished in order to obtain an increased application of starch in the paper industry in the future. This, in the case of market acceptable prices, would be in the interest of both industries.  相似文献   
75.
Igel M  Lindenthal B  Giesa U  von BK 《Lipids》2002,37(2):153-157
In the present study, the effect of leptin on intestinal cholesterol absorption was investigated in C57 BL/6 OlaHsd Lepob/Lepob obese (ob/ob) mice and lean C57 BL/6 (wild-type) mice. Animals were treated either with or without recombinant leptin for 2 wk. Cholesterol absorption was measured by the constant isotope feeding method and indirectly by the ratio of campesterol to cholesterol in serum. In ob/ob mice, cholesterol absorption was significantly higher compared to wild-type mice [83.4±2.3% (SD) vs. 77.6±1.5%, P<0.01]. Treatment with leptin significantly reduced cholesterol absorption in both ob/ob and wild-type mice by 8.5 (P<0.001) and 5.2% (P<0.05), respectively. Serum concentrations of campesterol and the ratio of campesterol to cholesterol in ob/ob mice were significantly higher compared to wild-type mice (2.2±0.3 mg/dL vs. 1.2±0.3 mg/dL, P<0.001; and 36.8±2.8 μg/mg vs. 28.0±3.3 μg/mg, P<0.001). After treatment of ob/ob mice with leptin, concentrations of campesterol and its ratio to cholesterol were significantly lower (2.2±0.3 mg/dL vs. 1.0±0.2 μg/mg, P<0.001; and 36.8±2.8 μg/mg vs. 13.2±2.2 μg/mg, P<0.001, respectively). In wild-type mice, the ratio of campesterol to cholesterol in serum was also significantly lower after treatment with leptin (28.0±3.3 μg/mg vs. 22.6±5.0 μg/mg, P<0.05). A significant positive correlation (r=0.701, P<0.01) between cholesterol absorption and the ratio of campesterol to cholesterol, in serum was found. It is concluded that leptin contributes to intestinal cholesterol absorption in ob/ob mice and lean wild-type mice.  相似文献   
76.
A key role for Artificial Intelligencetechnology in electronic commerce is in findingproducts and services that meet a user'srequirements. This may be implemented as athree-stage process of requirementselicitation, product search, and finallyproduct presentation. Alternatively the searchof the product space may happen in tandem withthe requirements elicitation process. It isalso possible to use product presentation as amechanism to focus and give context torequirements elicitation. A variety ofdifferent approaches to this issue of matchingproducts to requirements have been explored inAI research. Thus, while the focus in thispaper is on different approaches torequirements elicitation, these related issuesof product search and product presentation arealso discussed in detail. The paper concludesby placing the other papers in this specialissue in the context of this structuredoverview.  相似文献   
77.
X-ray Raman spectra of the carbon K-edge have been recorded using 6.461 keV radiation for a petroleum asphaltene. By comparison with coronene, graphite, and paraffin standards, the asphaltene spectrum is seen to be composed of contributions from saturated and aromatic carbon species. The information contained in the carbon K-edge was extracted with bulk (approximately 1 mm) sensitivity, because the Raman method used hard X-rays. This helps alleviate concerns about surface artifacts that frequently occur with soft X-ray spectroscopy of light elements. X-ray Raman spectroscopy shows great potential for characterization of light elements in fuels, catalysts, and other complex materials under chemically relevant conditions.  相似文献   
78.
Bergmann K  Rosier O  Neff W  Lebert R 《Applied optics》2000,39(22):3833-3837
An extreme-ultraviolet radiation source based on a xenon pinch plasma is discussed with respect to the demands on a radiation source for extreme-ultraviolet lithography. Operation of the discharge in a self-igniting-plasma mode and omitting a switch permits a very effective and low-inductive coupling of the electrically stored energy to the electrode system. The xenon plasma exhibits broadband emission characteristics that offer radiation near 11 and 13 nm. Both wavelengths are useful in combination with beryllium- and silicon-based multilayer mirrors. The plasma emits approximately 74 mW/sr at 11.5 nm and 40 mW/sr at 13.5 nm in a bandwidth of 2% when operated at a repetition frequency of 120 Hz. The source size is less than 500 mum in diameter (FWHM) when viewed from the axial direction. The pulse-to-pulse stability is better than 3.6%. First results with a repetition rate of as much as 6 kHz promise the possibility of scaling to the required emission power for extreme-ultraviolet lithography.  相似文献   
79.
From high-resolution infrared spectra of 14N12C12C14N, 14N13C13C14N, and 15N12C12C15N, we find that the levels 1000(0)0(0), 1000(0)1(1), 1000(0)2(0,2), and 1000(0)3(1,3) have very pronounced perturbations. Our analysis shows that these perturbations are due to a vibrational resonance among the levels 1000(0)0(0), 0102(0)2(0), and 0102(0)2(2) in the one case, and equivalent levels with one or more additional quanta of nu5 in the other three cases. The resonance constant for the perturbation involving nu1 is 0.25 cm-1. It has the dependence on v5 and l5 that is expected for the sextic potential constant, K124455, although it seems too large for such a high-order constant. The Deltal (or Deltak) = 2 interaction between, for instance, 1000(0)0(0) and 0102(0)2(2e) is shown to be primarily due to the l-type resonance mixing of the 0102(0)2(0) and 0102(0)2(2e) states. The resonance is nearly "turned off" for the 1000(0)2(0,2) and 1000(0)3(1,3) states of 14N13C13C14N because there are no level crossings between the interacting states and the band centers are too far away to have an obvious effect, although careful analysis shows that the perturbation can be seen in their effective centrifugal distortion constants. The spectrum of 15N12C12C15N shows level crossings only in the case of the 1000(0)1(1), 1000(0)2(0,2), and 1000(0)3(1,3) states. Copyright 1999 Academic Press.  相似文献   
80.
Even simple and relatively safe provocation procedures like nasal allergen challenges, should aim to allow detection of positivity with the less possible discomfort to the patient. The objective of this work was to evaluate if the use of rhinomanometric measurements during nasal provocation procedures could allow a decrease in the total administered allergen dose, causing less symptoms to the patients but without increasing the number of false-negatives, comparatively to clinical scores or nasal peak-flow measurements. Our results showed that performing rhinomanometric measurements during nasal HDM challenge procedures can lead in many patients to a reduction in the total dose of allergen administered during the challenge, without loss of sensitivity or specificity. This allergen dose reduction translates in less time consumed during the provocation and less patients' discomfort.  相似文献   
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