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排序方式: 共有250条查询结果,搜索用时 31 毫秒
51.
Daniel Povey Lukáš Burget Mohit Agarwal Pinar Akyazi Feng Kai Arnab Ghoshal Ondřej Glembek Nagendra Goel Martin Karafiát Ariya Rastrow Richard C. Rose Petr Schwarz Samuel Thomas 《Computer Speech and Language》2011,25(2):404-439
We describe a new approach to speech recognition, in which all Hidden Markov Model (HMM) states share the same Gaussian Mixture Model (GMM) structure with the same number of Gaussians in each state. The model is defined by vectors associated with each state with a dimension of, say, 50, together with a global mapping from this vector space to the space of parameters of the GMM. This model appears to give better results than a conventional model, and the extra structure offers many new opportunities for modeling innovations while maintaining compatibility with most standard techniques. 相似文献
52.
We have made an investigation on the resonance states in two-electron systems interacting with exponential cosine-screened Coulomb potentials (ECSCP) within the framework of stabilization method. Highly correlated wave functions are used to take into account the correlations of the charge particles. Results for resonance energies and widths are reported for Z=1,2 and 3. For the unscreened case, our reported results are in nice agreement with the results so far available in the literature. 相似文献
53.
Itaconic acid used as a versatile building block for the synthesis of renewable resource‐based resins and polyesters for future prospective: a review
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Sudheer Kumar Sukhila Krishnan Sushanta K Samal Smita Mohanty Sanjay K Nayak 《Polymer International》2017,66(10):1349-1363
Itaconic acid, a carbohydrate‐derived aliphatic dicarboxylic acid, is a potential chemical for the synthesis of renewable resource‐based resins and polyesters. Owing to environmental reasons, there is a gradual demand for renewable resources in the chemical industry. Conversely, as a rather underappreciated side effect of this growth, novel chemical building blocks are obtained, which are not commercially derived from petrochemical sources. In this respect, itaconic acid has attracted much attention and its trifunctional structure leads to the synthesis of novel polymeric materials. This review discusses the most relevant information for bio‐based resins and polyesters resulting from itaconic acid and distinctive properties for various commercial applications. © 2017 Society of Chemical Industry 相似文献
54.
Optical properties of nano-silicon 总被引:2,自引:0,他引:2
We investigated the optical properties of silicon clusters and Si nanocrystallites using photolumine-scence (PL) and Raman
scattering technique. Broad luminescence band in the red region was observed from Si-doped SiO2 thin films deposited by co-sputtering of Si and SiO2 onp-type Si (100) substrates, annealed in Ar and O2 atmosphere. Nanocrystalline Si particles fabricated by pulsed plasma processing technique showed infrared luminescence from
as grown film at room temperature. Raman spectra from these films consisted of broad band superimposed on a sharp line near
516 cm−1 whose intensity, frequency, and width depend on the particle sizes arising from the phonon confinement in the nanocrystalline
silicon. We also performed PL, Raman and resonantly excited PL measurements on porous silicon film to compare the optical
properties of Si nanostructures grown by different techniques. An extensive computer simulation using empirical pseudo-potential
method was carried out for 5–18 atoms Si clusters and the calculated gap energies were close to our PL data.
Paper presented at the 5th IUMRS ICA98, October 1998, Bangalore. 相似文献
55.
56.
Sushanta Borah Ananta M. Baruah Arup K. Das Junmoni Borah 《Food Analytical Methods》2009,2(3):226-230
Vegetables used by the people of Assam (India) found to be highly nutritious to maintain general balance diet. Nutritional
information is used increasingly by public agencies and agricultural industries to promote different traditional fresh product.
The work aimed at determining few nutritionally important minerals (calcium, iron, magnesium, phosphorus, and potassium) in
leafy green vegetables widely consumed in Assam. The objective of the present work was to examine the variability in the mineral
content. 相似文献
57.
The scattering of elastic waves in polycrystalline materials is relevant for ultrasonic materials characterization and nondestructive evaluation (NDE). Diffuse ultrasonic backscatter measurements are used widely to extract the microstructural parameters such as grain size and also to detect flaws in materials. Accurate interpretation of experimental data requires robust scattering models. Line transducers are often used for ultrasonic experiments such that an appropriate model for these two-dimensional problems is needed. Here, a theoretical expression for the temporal diffuse backscatter is derived for such domains under a single-scattering assumption. The result is given in terms of transducer and microstructural parameters. In addition, the problem is examined in terms of numerical simulations using Voronoi polycrystals that are discretized using finite elements in a plane-strain formulation. The material properties of the individual Voronoi cells are chosen according to appropriate material distributions. Such numerical models also allow scattering theories, including the one discussed here, to be examined for well-controlled microstructures. Example numerical results for materials with varying degrees of scattering that are of common interest are presented. The numerical results are compared with the theory developed with good agreement. These results are anticipated to impact ultrasonic NDE of polycrystalline media. 相似文献
58.
Debasis Mitra Sarmishtha Ghoshal Hafizur Rahaman Krishnendu Chakrabarty Bhargab B. Bhattacharya 《Journal of Electronic Testing》2011,27(5):657-671
Digital microfluidic technology is now being extensively used for implementing a lab-on-a-chip. Microfluidic biochips are
often used for safety-critical applications, clinical diagnosis, and for genome analysis. Thus, devising effective and faster
testing methodologies to warrant correct operations of these devices after manufacture and during bioassay operations, is
very much needed. In this paper, we propose an Euler tour based technique to obtain the route plan of a test droplet for the
purpose of structural testing of biochips. The method is applicable to various digital microfluidic biochip architectures,
e.g., fully reconfigurable arrays, application specific biochips, pin-constrained irregular geometry biochips, and to defect-tolerant
biochips. We show that in general, the optimal Eulerization and subsequent determination of an Euler tour in the graph model
of a biochip can be abstracted in terms of the classical Chinese postman problem. The Euler tour can be identified by running
the classical Hierholzer’s algorithm, which relies on a simple cycle decomposition and splicing method. This improved Eulerization
technique leads to an efficient test plan for the chip. This can also be used in phase-based test planning that yields savings
in testing time. The method provides a unified approach towards structural testing and can be easily adopted to design a droplet
routing procedure for functional testing of digital microfluidic biochips. 相似文献
59.
Sushanta Kumar PanigrahiR. Jayaganthan 《Journal of Alloys and Compounds》2011,509(40):9609-9616
The effect of ageing on mechanical properties and microstructural characteristics of a precipitation hardenable Al 7075 alloy subjected to rolling at liquid nitrogen temperature and room temperature are has been investigated in the present work employing hardness measurements, tensile test, XRD, DSC, and TEM. The solution-treated bulk Al 7075 alloy was subjected to cryorolling and room temperature rolling to refine grain structures and subsequently ageing treatment to simultaneously improve the strength and ductility. The solution treatment combined with cryorolling up to a true rolling strain of 2.3 followed by low temperature ageing at 100 °C for 45 h has been found to be the optimum processing condition to obtain fine grained microstructure with improved tensile strength (642 MPa) and good tensile ductility (9.5%) in the Al 7075 alloy. The combined effect of suppression of dynamic recovery, partial grain refinement, partial recovery, solid solution strengthening, dislocation hardening, and precipitation hardening are responsible for the significant improvement strength-ductility combination in the cryorolled Al 7075 alloy subjected to peak ageing treatment. The cryorolled and room temperature rolled Al 7075 alloy, upon subjecting to peak ageing treatment, have shown higher strength and ductility in the former than the latter. It is due to presence of high density of nanosized precipitates in the peak aged cryorolled sample. 相似文献
60.
Increasing levels of wind generation have resulted in an urgent need for the assessment of their impact on frequency control of power systems. The displacement of conventional generation with wind generation will result in erosion of system frequency. The paper analyzed the dynamic participation of doubly fed induction generator (DFIG) to system frequency responses of two-area interconnected power system having variety of conventional generating units. Frequency control support function responding proportionally to frequency deviation is proposed to take out the kinetic energy of turbine blades in order to improve the frequency response of the system. Impacts of different wind penetrations in the system and varying active power support from wind farm on frequency control have been investigated. Integral gains of AGC loop are optimized through craziness-based particle swarm optimization (CRPSO) in order to have optimal transient responses of area frequencies, tie-line power deviation and DFIG parameters. 相似文献