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991.
A large subset of the language Algol 68 has been implemented on a small computer—the TESLA 200 with a 64 Kbyte store. In this paper, the general structure of the compiler and organization of the program at run-time are described. Especially, the original methods and devices are mentioned that cause a considerable enhancement of the speed of compilation and program run. These concern the syntax analysis (consistent notation, error recovery), the organization of the resulting program (procedure organization, algorithms of work with multiple values) and the techniques of code generation. We try to show that Algol 68 is a suitable programming language for small as well as large computers and that it can successfully compete with traditional programming languages. 相似文献
992.
The structures of the acid, base, polyfunctional and neutral resin fractions of Millmerran coal tar have been studied by high-pressure catalytic hydrogenolysis followed by g.c.-m.s. analysis of the volatile products. n-Alkanes from C9 to C32 constitute 4–24% of the organic products. Each fraction shows a characteristic n-alkane distribution. The alkanes are considered to be an integral part of the coal-tar resin structure. The results show that 40–70% of the coal-tar resin fractions consist of 1- or 2-ring aromatic units substituted or linked by long methylene chains. 相似文献
993.
Compares the plight of a research S with that of a student taking a routine examination in one of his classes, and judges the latter to be more vulnerable. A code of ethics to protect the hapless student from unscrupulous professors is generated by slightly modifying the proposed American Psychological Association code of research ethics. After this flight into fantasy, it is acknowledged that psychology's research deportment has not been entirely exemplary. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
994.
Operator of proposed low-reflecting boundary conditions is derived by approximation of discrete transparent boundary conditions obtained numerically. Reasonable computational costs are achieved due to sum-of-exponentials representation of occurring temporal kernels. 相似文献
995.
Decomposition of toxic pollutants in landfill leachate by ozone after coagulation treatment 总被引:4,自引:0,他引:4
Poznyak T Bautista GL Chaírez I Córdova RI Ríos LE 《Journal of hazardous materials》2008,152(3):1108-1114
This study deals with evaluation of organic matter from Mexico City waste sanitary landfill leachate of Bordo Poniente (including domestic and industrial) by ozonation after a coagulation treatment with Fe2(SO4)(3) (2.5 g/L at pH 4-5). The content of humic substances after the coagulation treatment decreases up to 70%. Then leachate obtained from a solid with initial COD=1511 mg/L and the pH 8.5 was treated by ozone. The aqueous samples by a UV-vis and HPLC technique were analyzed. The partial identification of the initial composition of the organic matter as well as of intermediates and final products was carried out after the extraction of the initial and ozonated leachate with benzene, chloroform:methanol (2:1) and hexane. Then the extracts with a gas chromatograph with mass detector and FID were analyzed. In the HPLC results we identify malonic and oxalic acids. The initial concentrations of these acids were 19 mg/L and 214 mg/L, respectively. The oxalic acid is formatted and accumulated in ozonation. The obtained results show that the color disappears (visually) at 100% during 5 min of ozonation. The organic substances, extracted with chloroform-methanol, may be destructed during 15 min of ozonation; the organic matter, extracted with benzene, destructs completely by ozone during 5 min, and the organic compounds extracted with hexane have a low ozonation rate. The toxic compounds presented in leachate decompose completely during 15 min of ozonation. The ozonation rate constants for each group of organics (as observed constants) were calculated applying simplified mathematical model and the recurrent least square method using the program MATLAB 6.5. 相似文献
996.
Approaching ballistic transport in suspended graphene 总被引:6,自引:0,他引:6
The discovery of graphene raises the prospect of a new class of nanoelectronic devices based on the extraordinary physical properties of this one-atom-thick layer of carbon. Unlike two-dimensional electron layers in semiconductors, where the charge carriers become immobile at low densities, the carrier mobility in graphene can remain high, even when their density vanishes at the Dirac point. However, when the graphene sample is supported on an insulating substrate, potential fluctuations induce charge puddles that obscure the Dirac point physics. Here we show that the fluctuations are significantly reduced in suspended graphene samples and we report low-temperature mobility approaching 200,000 cm2 V-1 s-1 for carrier densities below 5 x 109 cm-2. Such values cannot be attained in semiconductors or non-suspended graphene. Moreover, unlike graphene samples supported by a substrate, the conductivity of suspended graphene at the Dirac point is strongly dependent on temperature and approaches ballistic values at liquid helium temperatures. At higher temperatures, above 100 K, we observe the onset of thermally induced long-range scattering. 相似文献
997.
Arianna Marelli Ivan Roberto De Vita Federica Cozza Silvia Tavazzi 《Contact lens & anterior eye》2018,41(6):531-537
Purpose
The aim was to evaluate the effects on corneal thickness (t) measurement, of asymmetry of the CCD position for a digital biomicroscope in specular reflection.Methods
t was deduced from the distance between reflexes from anterior and posterior corneal surfaces using a biomicroscope (Takagi SM70?N), with the illuminator either, (a) farther from sensor side (150 eyes) or, (b) closer to it (134 eyes). The distance between reflexes was also measured on a glass slide and a reference lens, with nominal thicknesses of 1580 and 520?μm, respectively. Corneal thickness (tPACH) was also measured by pachymeter (Canon TX-20?P).Results
When biomicroscope asymmetry was ignored, t for the glass slide was (a) 1760 and (b) 1404?μm. Correcting for the asymmetry provided corresponding values of 1588 and 1591?μm. For the lens, t was (a) 696 and (b) 543?μm, or 642 and 497?μm, when using the approximation of parallel surfaces (APS). Correcting for the asymmetry gave 565 and 552?μm (578 and 564?μm, with APS). Mean corneal t was (a) 560 and (b) 467?μm, (564 and 468?μm, with APS). Correcting for asymmetry gave (a) 506 and (b) 529?μm (508 and 530?μm, with APS). Mean tPACH was 552?μm.Conclusion
Biomicroscope asymmetry critically affects corneal thickness measurement in specular reflection. Induced errors can be accounted for and corrected, however. While the correction to the curvature radius is clinically relevant, it plays a minor role compared to asymmetry. 相似文献998.
Partserniak I Werstuck G Capretta A Brennan JD 《Chembiochem : a European journal of chemical biology》2008,9(7):1065-1073
Glycogen synthase kinase-3beta (GSK-3beta) is involved in the hyperphosphorylation of previously phosphorylated (primed) substrates, and is currently assayed using an approach based on the incorporation of gamma-(32)P-radiolabelled isotopes into substrate peptides. The requirement to detect hyperphosphorylation of a primed substrate poses a particular challenge for development of a high-throughput screening assay, as many current kinase assays are designed to produce a signal in the presence of any phosphorylation site, and thus are only suitable for beta-unphosphorylated substrates. Herein, we have developed an electrospray-ionization tandem mass spectrometry (ESI-MS/MS) assay to allow for direct detection of a hyperphosphorylated product which is formed in a solution reaction involving a primed peptide substrate (GSM peptide) and GSK-3beta. Optimum reaction conditions (level of Mg(2+), buffer type, ionic strength, pH, enzyme concentration, and reaction time) were established to both maintain the activity of GSK-3beta and allow for substrate and product quantification through ESI/MS/MS. We show that the MS-based assay allows for rapid determination of GSK-3beta activity from reaction volumes of approximately 40 microL and that it can be used to assess IC(50) values and the site of action of known inhibitors. It also can be used for automated screening of small-molecules mixtures to identify inhibitors of GSK-3beta. 相似文献
999.
Terzić S Senta I Ahel M Gros M Petrović M Barcelo D Müller J Knepper T Martí I Ventura F Jovancić P Jabucar D 《The Science of the total environment》2008,399(1-3):66-77
This paper reports on a comprehensive reconnaissance of over seventy individual wastewater contaminants in the region of Western Balkan (WB; Bosnia and Herzegovina, Croatia and Serbia), including some prominent classes of emerging contaminants such as pharmaceuticals and personal care products, surfactants and their degradation products, plasticizers, pesticides, insect repellents, and flame retardants. All determinations were carried out using a multiresidue analytical approach, based on the application of gas chromatographic and liquid chromatographic techniques coupled to mass spectrometric detection. The results confirmed a widespread occurrence of the emerging contaminants in municipal wastewaters of the region. The most prominent contaminant classes, determined in municipal wastewaters, were those derived from aromatic surfactants, including linear alkylbenzene sulphonates (LAS) and alkylphenol polyethoxylates (APEO), with the concentrations in raw wastewater reaching into the mg/l range. All other contaminants were present in much lower concentrations, rarely exceeding few microg/l. The most abundant individual compounds belonged to several classes of pharmaceuticals (antimicrobials, analgesics and antiinflammatories, beta-blockers and lipid regulators) and personal care products (fragrances). Due to the rather poor wastewater management practices in WB countries, with less than 5% of all wastewaters being biologically treated, most of the contaminants present in wastewaters reach ambient waters and may represent a significant environmental concern. 相似文献
1000.
Lapchuk AS Shylo SA Nevirkovets IP 《Journal of the Optical Society of America. A, Optics, image science, and vision》2008,25(7):1535-1540
A local plasmon resonance on a metal wedge is studied by using the Meixner approach [J. Meixner, IEEE Trans. Antennas Propag.AP-20, 442 (1972)]. It is found that the singular field behavior of a local plasmon resonance as a function of the distance from the edge of the wedge is sensitive to the wavelength and wedge angle, and ranges from a dramatic increase in amplitude close to its theoretical limit to pure oscillatory behavior with only minor amplitude variation. Field singularities for gold, silver, and aluminum wedges are calculated. It is shown that, unlike an ideal-conductor wedge, the real part of the power index of the electric field singularity does not decrease monotonically as a function of the wedge angle, but has a minimum for some angle depending on the wavelength and material parameters. If the dielectric surrounding the wedge has a positive permittivity equal to the absolute value of that of the metal, and hence satisfies the plasmon resonance condition, then the electric field has a peculiar behavior for a wedge whose shape is close to the flat surface. 相似文献