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261.
A new 3D exhaustive ray tracing algorithm for microcells is presented. This algorithm, based on an intelligent sequence search and Fermat's principle, overcomes some of the limitations of `brute force' ray tracing and image theory 相似文献
262.
A method to develop cross-assemblers is explained by describing the XMETA system, where the advantages given by the semantic power of meta-assemblies have been combined with the clarity of modern high level languages, such as Pascal, in defining assembly semantics. XMETA accepts a superset of the IEEE-P694 microprocessor assembly language standard syntax: system structure is detailed and examples are provided to illustrate its use. Actual experiences are briefly summarized in the conclusions. 相似文献
263.
Aurealice Rosa Maria Martins Isaias Donizeti Silva Luciana Machado-Santos Rafael Pino Vitti Mário Alexandre Coelho Sinhoreti William Cunha Brandt 《应用聚合物科学杂志》2021,138(21):50498
The aim of this study was to evaluate the effects of isobornyl methacrylate (IBOMA) as a diluent co-monomer on the physical properties of experimental resins. Blends of bisphenol glycidyl methacrylate (Bis-GMA) were formulated with triethylene glycol dimethacrylate (TEGDMA) and IBOMA in different wt%. The degree of conversion, flexural strength, elastic modulus, and ultimate tensile strength were determined. Immediate and 24 h volumetric shrinkage were calculated. Data were submitted to ANOVA and Tukey's tests (α = 0.05). Blends of Bis-GMA and IBOMA showed the lowest ultimate tensile strength, flexural strength, elastic modulus, degree of conversion, and immediate and 24 h volumetric shrinkage results. However, when IBOMA was used together with TEGDMA in blends of Bis-GMA, the resin composites showed best curing performance and high physical-mechanical properties. Thus, the IBOMA is as diluent co-monomer that can be used in dental resin composites to reduce the volumetric shrinkage. 相似文献
264.
265.
WO3 and Ag-WO3 nanocomposite thin films have been synthesized from pure WO3 and Ag-WO3 composite pressed powder targets submitted to pulses generated by a frequency quadrupled Nd:yttrium aluminium garnet (YAG;
λ = 266 nm, τ ~ 5 ns, ν = 10 Hz) laser source. The irradiations were performed in low pressure oxygen atmosphere. The obtained
results proved the possibility to tailor the synthesized thin films optical properties in the UV–Visible spectral region and
their nano-scale electrical characteristics through the process parameters, as ambient oxygen pressure value during the thin
films deposition and Ag concentration of the Ag-WO3 composite targets. The tunable optical and electrical features allow for the creation of new materials for future applications
as photocatalysts, transparent conducting electrodes, electrochromic or chemical and biological sensor devices. 相似文献
266.
Commercially produced Persian lime essential oil was qualitatively and quantitatively analyzed by GC-MS. The oxygenated components represent 25% of the total composition. The major and most of the minor components we isolated from essence oil had been previously identified from coldpressed oil or aqueous essence. Three minor components, 3-methyl-2-butanol, trans carvyl and cis carvyl acetate, not previously found in lime, were identified in this study. 相似文献
267.
Validation of a HS-SPME-GC Method for Determining Higher Fatty Esters and Oak Lactones in White Rums
Higher fatty esters and oak lactones are the main components of white rum aroma and furthermore, they have an important sensorial impact in these distilled alcoholic beverages. A method for analyzing these volatile compounds was validated. It involves a separation and concentration step using headspace solid-phase microextraction (HS-SPME) and determination by capillary gas chromatography using flame ionization detection. The method showed a good within-day (RSD?<?3 %) and between-day precision (RSD?<?5 %). The calibration curves were linear at the tested ranges (R?>?0.99) and the limits of detection and quantification were 0.001–0.018 and 0.003–0.054 mg L?1 (12 %?v/v alcohol), respectively. Good recoveries were obtained (98.6–100.3 %). The method is suitable for the quality control of higher fatty esters and oak lactones in white rums. 相似文献
268.
Dionísio F. Silva Almir Oliveira Neto Eddy S. Pino Marcelo Linardi Estevam V. Spinac 《Journal of power sources》2007,170(2):303-307
PtRu/C electrocatalysts (carbon-supported PtRu nanoparticles) were prepared submitting water/ethylene glycol solutions containing Pt(IV) and Ru(III) ions and the carbon support to γ-irradiation. The water/ethylene glycol ratio (v/v) and the total dose (kGy) were evaluated as synthesis parameters. The electrocatalysts were characterized by energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM) and cyclic voltammetry and tested for methanol electro-oxidation aiming fuel cell application. The obtained PtRu/C electrocatalysts were more active for methanol electro-oxidation than the commercial PtRu/C electrocatalyst at ambient temperature and the electrocatalytic activity depends on the water/ethylene glycol ratio used in the preparation. 相似文献
269.
Analysis of volatile compounds of pineapple wine using solid-phase microextraction techniques 总被引:2,自引:0,他引:2
An analytical procedure based on headspace solid-phase microextraction (HS-SPME) method combined with GC–MS was developed for the extraction and quantification of volatile compounds from pineapple wine. Different sample preparation (SPME fibre type, addition of sodium chloride, extraction time and temperature) were evaluated to optimise the method. For the final method, 8 ml of pineapple wine were placed in a 15 ml headspace vial with addition of 1 g of NaCl; a polydimethylsiloxane SPME fibre was used for extraction at 30 °C for 30 min with continuous stirring. The volatile compounds have shown a good linearity in the range of concentrations studied with regression coefficients higher than 0.98, and the reproducibility expressed as relative standard deviation ranged from 4.2% (2-phenylethyl acetate) to 7.1% (ethyl benzoate). The values obtained for detection and quantification limits were low enough to permit the determination of volatiles in pineapple wine. Using this method, 18 volatiles were identified, including 13 esters, 4 alcohols and one acid. Ethyl octanoate, ethyl acetate, 3-methyl-1-butanol and ethyl decanoate were the major constituents. A tentative study to estimate the contribution of the identified compounds to the aroma of the wine, on the basis of their odour activity values (OAV), indicated that the compounds potentially most important to pineapple wine included ethyl octanoate, ethyl acetate and ethyl 2-methylpropanoate. 相似文献