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Economics-related ICT research has moved from the fringes of the discipline to penetrate all of its branches. It is, therefore, not a separate economics subdiscipline. It is also unlikely to become part of an “ICT or Internet research” proto-discipline. Instead, it should be seen as only one part of a bigger agenda toward a proper “information and knowledge economics” and possibly a future proto-discipline of a “unified theory of information and knowledge” or a meta-discipline of information sciences.  相似文献   

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This article examines the digital divide in terms of access and the cultural use purposes of the Internet in Finland, the United Kingdom, and Greece. The analysis is based on data from Finnish, British, and Greek sections of Eurobarometer collected in 2013 (N = 3,009). Separate measures for class and status are applied in the analysis. The findings indicate that both access to and use of the Internet for cultural purposes are affected by a number of interdependent factors, whose effects and strengths vary significantly among the countries.  相似文献   

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Using the velocity analyzer of Zartman with improved technique the combined velocity spectrum of Bi atoms and Bi2 molecules was obtained at 827°, 851°, 875°, 899°, 922°, 947° C. From the spectral distribution curves the relative abundance of Bi atoms and Bi2 molecules in the beams at the above temperatures could be determined to 1 per cent. The vapor pressure curve of Bi was obtained experimentally by the method of effusion and the values so obtained were combined with the degree of dissociation of the vapor as computed from the beams to give the heat of dissociation. The heat of dissociation was computed from the data, assuming the pressure to be given by the temperature of the crucible Tc. In calculating the heat of dissociation, the equilibrium temperature was taken as that of the slit chamber Ts which was 24° above Tc. The results of these calculations plotted with log10Kp as ordinates against 1Ts give a straight line whose slope yields the value of the heat of dissociation as 77,100±1200 calories. The curves for the distribution of velocities observed and computed on the assumption of a given ratio of Bi atoms to Bi2 molecules in the beam were compared in an attempt to test the law of distribution of velocities. On the high velocity side agreement in two curves was obtained within the limits of experimental accuracy. On the low velocity side important deviations were noted of such a sort that the observed curves below a velocity α2, (α is the most probable velocity) gave more molecules than the theory demanded. Other deviations were observed on some of the runs taken with a fourth slit in which a deficiency of molecules was observed between velocities of .75α and α2. This deviation was probably due to a warping of the fourth slit carriage due to heat. The nature of the variation at velocities less than α2 indicated the presence of molecules of greater mass than Bi2 in the beam and at the lower temperatures a distinct peak corresponding to Bi8 molecules was observed which were present to less than 2 per cent. The vapor pressure curve for Bi was determined by least square reduction of the observed points to be given by log10 P = ? 52.23 × 195.26T + 8.56 between 1100° and 1220° abs. It lies very close to the extrapolated curve given in the International Critical Tables.  相似文献   

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《Endeavour》1999,23(2):72-75
The central role that the theory of terrestrial temperatures played in Fourier's mathematical physics has not received the attention it deserves from historians, although his cryptic allusions to the heating of a greenhouse, taken out of context, have been widely cited by subsequent authors.  相似文献   

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Direct absorption of light by glycosides dissolved in water has been discovered to produce changes in optical activities and formation of material which reduces the Shaffer, Hartmann, Somogyi reagent. Comparison of these measurements indicates in many cases the same products as are formed by hydrolysis in acid. The β glucosides and α fructoside, however, apparently give optically inactive photolytic products.Absorption spectra were obtained for α benzylfructofuranoside and β benzylfructopyranoside, and were found to be the same in the near ultraviolet as those previously obtained for benzyl glucosides and benzyl alcohol.The absorption spectrum for freshly purified fructose gives a deeper minimum about λ240 mμ than the previously reported values. The latter, however, were approached when the dry crystals had stood in air for several months although no change occurred in their sp.rot., m.p. or general apperance.All the glycosides studied were white crystalline compounds. Less than five per cent. of the ultraviolet light of λ254 mμ they absorb produces reaction; nevertheless, the apparatus and procedures available were adequate to study the reaction conveniently in monochromatic light of this wave-length.The absorption spectra, the products of photolysis, and the quantum yields, the latter based on the reducing material formed, lead to the hypothesis that the photochemical reaction is produced by an intramolecular transfer of absorbed energy from the aglycone to the hemiacetal oxygen bridge which is the reactive center. The efficiency of this transfer is, as expected, greater for benzyl than for phenylethyl glucosides but phenyl glucosides, contrariwise, are the least efficient.The structure and energy possessed by the glycoside outside the aglycone have no measurable effect on the efficiency of the photochemical reaction when followed by measuring the reducing material produced although they change up to one hundred thousand fold the rates of the thermal hydrolyses in acid.  相似文献   

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This article asks whether the global process of digitization has led to noteworthy changes in the shares of the amount of text, images, audio, and video in worldwide technologically stored and communicated information content. We empirically quantify the amount of information that is globally broadcast, telecommunicated, and stored (1986–2007) and assess the evolution of the respective content shares. Somewhat unexpectedly, it turns out that the transfer from analog to digital has not led to toward increasing shares of media-rich audio and video content, despite vastly increased bandwidth. First, there is a certain inertia in the evolution of content, which seems to stick to stable proportions independent of its technological medium (be it analog vinyl and VHS tapes, or digital CDs and hard disks). Second, the relative share of text and still images actually captures a larger portion of the total amount than before the digital age. Text merely represented 0.3% of the (optimally compressed) bits that flowed through global information channels in 1986 but grew to almost 30% in 2007. On another level, we are seeing an increasing transition of text and images from one-way information diffusion networks (like newspapers) to digital storage and two-way telecommunications networks, where they are more socially embedded. Both tendencies are good news for big-data analysts who extract intelligence from easily analyzable text and image data.  相似文献   

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In the August 2020 issue of Clinical Chemistry and Laboratory Medicine, Giuseppe Lippi and Mario Plebani proposed a definition of laboratory medicine, which ends with this sentence: “The results of these measurements are translated into actionable information for improving the care and/or maintaining the wellness of both a single individual and an entire population”. Nevertheless, the selfishness of individuals may, sometimes, jeopardize the interest of whole populations. The virtue of justice being within the reach of the entire human community more than of single individuals, the final sentence in the definition proposed by Giuseppe Lippi and Mario Plebani, should therefore, in our view, be rewritten, less selfishly, for example like this: “For a given investment, these measurements are preferably made when they bring as much beneficence, and non-maleficence, as possible to the whole population”.  相似文献   

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A review is presented of the present status of the theory, the developed technology and the current applications of dielectrophoresis (DEP). Over the past 10 years around 2000 publications have addressed these three aspects, and current trends suggest that the theory and technology have matured sufficiently for most effort to now be directed towards applying DEP to unmet needs in such areas as biosensors, cell therapeutics, drug discovery, medical diagnostics, microfluidics, nanoassembly, and particle filtration. The dipole approximation to describe the DEP force acting on a particle subjected to a nonuniform electric field has evolved to include multipole contributions, the perturbing effects arising from interactions with other cells and boundary surfaces, and the influence of electrical double-layer polarizations that must be considered for nanoparticles. Theoretical modelling of the electric field gradients generated by different electrode designs has also reached an advanced state. Advances in the technology include the development of sophisticated electrode designs, along with the introduction of new materials (e.g., silicone polymers, dry film resist) and methods for fabricating the electrodes and microfluidics of DEP devices (photo and electron beam lithography, laser ablation, thin film techniques, CMOS technology). Around three-quarters of the 300 or so scientific publications now being published each year on DEP are directed towards practical applications, and this is matched with an increasing number of patent applications. A summary of the US patents granted since January 2005 is given, along with an outline of the small number of perceived industrial applications (e.g., mineral separation, micropolishing, manipulation and dispensing of fluid droplets, manipulation and assembly of micro components). The technology has also advanced sufficiently for DEP to be used as a tool to manipulate nanoparticles (e.g., carbon nanotubes, nano wires, gold and metal oxide nanoparticles) for the fabrication of devices and sensors. Most efforts are now being directed towards biomedical applications, such as the spatial manipulation and selective separation∕enrichment of target cells or bacteria, high-throughput molecular screening, biosensors, immunoassays, and the artificial engineering of three-dimensional cell constructs. DEP is able to manipulate and sort cells without the need for biochemical labels or other bioengineered tags, and without contact to any surfaces. This opens up potentially important applications of DEP as a tool to address an unmet need in stem cell research and therapy.  相似文献   

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