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A complete set of match calculation methods for optimum sizing of PV/wind hybrid system is presented. In this method, the more accurate and practical mathematic models for characterizing PV module, wind generator and battery are a...
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A complete set of match calculation methods for optimum sizing of PV/wind hybrid system is presented. In this method, the more accurate and practical mathematic models for characterizing PV module, wind generator and battery are adopted; combining with hourly measured meteorologic data and load data, the performance of a PV/wind hybrid system is determined on a hourly basis; by fixing the capacity of wind generators, the whole year's LPSP (loss of power supply probability) values of PV/wind hybrid systems with different capacity of PV array and battery bank are calculated, then the trade-off curve between battery bank and PV array capacity is drawn for the given LPSP value; the optimum configuration which can meet the energy demand with the minimum cost can be found by drawing a tangent to the tradeoff curve with the slope representing the relationship between cost of PV module and that of the battery. According to this match calculation method, a set of match calculation programs for optimum sizing of PV/wind hybrid systems have been developed. Applying these match calculation programs to an assumed PV/wind hybrid system to be installed at Waglan island of Hong Kong, the optimum configuration and its hourly, daily, monthly and yearly performances are given.
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A fully three-dimensional, nonlinear, time-dependent spherical interface dynamo is investigated using a finite-element method based on the three-dimensional tetrahedralization of the spherical system. The spherical interface dynam...
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A fully three-dimensional, nonlinear, time-dependent spherical interface dynamo is investigated using a finite-element method based on the three-dimensional tetrahedralization of the spherical system. The spherical interface dynamo model consists of four zones: an electrically conducting and uniformly rotating core, a thin differentially rotating tachocline, a uniformly rotating turbulent convection envelope, and a nearly insulating exterior. The four regions are coupled magnetically through matching conditions at the interfaces. Without the effect of a tachocline, the conventional nonlinear α~2 dynamo is always stationary, axisymmetric, and equatorially antisymmetric even though numerical simulations are always fully three-dimensional and time dependent. When there is no tachocline, the azimuthal field is confined to the convection zone while the poloidal magnetic field penetrates into the radiative core. The effects of an interface dynamo with a tachocline having a purely axisymmetric toroidal velocity field are as follows: (1) the action of the steady tachocline always gives rise to an oscillatory dynamo with a period of about 2 magnetic diffusion units, or about 20 yr if the magnetic diffusivity in the convection zone is 10~8 m~2 s~(-1); (2) the interface dynamo solution is always axisymmetric, selects dipolar symmetry, and propagates equatorward (for the assumed form of α) although the simulation is fully three-dimensional; (3) the generated magnetic field mainly concentrates in the vicinity of the interface between the tachocline and the convection zone; and (4) the strength of the toroidal magnetic field is dramatically amplified by the effect of the tachocline. Extensions of Cowling's theorem and the toroidal flow theorem to multilayer spherical shell regions with radially discontinuous magnetic diffusivities are presented.
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Mycoplasma gallisepticum, a significant respiratory and reproductive pathogen of domestic poultry, has since 1994 been recognized as an emergent pathogen of the American house finch (Carpodacus mexicanus). Epizootic spread and pat...
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Mycoplasma gallisepticum, a significant respiratory and reproductive pathogen of domestic poultry, has since 1994 been recognized as an emergent pathogen of the American house finch (Carpodacus mexicanus). Epizootic spread and pathognomonic characteristics of house finch-associated Mycoplasma gallisepticum (HFMG) have been studied as a model of an emergent to endemic pathogen in a novel host. Here we present comparative analysis of eight HFMG genomes, including one from an index isolate and seven isolates separated spatially and temporally (1994–2008) across the epizootic, and notably having differences in virulence. HFMG represented a monophyletic clade relative to sequenced poultry isolates, with genomic changes indicating a novel M. gallisepticum lineage and including unique deletions of coding sequence. Though most of the HFMG genome was highly conserved among isolates, genetic distances correlated with temporal–spatial distance from the index. The most dramatic genomic differences among HFMG involved phase-variable and immunodominant VlhA lipoprotein genes, including those variable in presence and genomic location. Other genomic differences included tandem copy number variation of a 5 kbp repeat, changes in and adjacent to the clustered regularly interspaced short palindromic repeats, and small-scale changes affecting coding potential and association of genes with virulence. Divergence of monophyletic isolates from similar time/space in the epizootic indicated local diversification of distinct HFMG sublineages. Overall, these data identify candidate virulence genes and reveal the importance of phase-variable lipoproteins during the evolution of M. gallisepticum during its emergence and dissemination in a novel host in nature, likely mediating an important role at the interface between pathogen virulence and host immunity.
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The QCDSP and QCDOC computers are two generations of multithousand-node multidimensional mesh-based computers designed to study quantum chromodynamics (QCD), the theory of the strong nuclear force. QCDSP (QCD on digital signal pro...
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The QCDSP and QCDOC computers are two generations of multithousand-node multidimensional mesh-based computers designed to study quantum chromodynamics (QCD), the theory of the strong nuclear force. QCDSP (QCD on digital signal processors), a four-dimensional mesh machine, was completed in 1998; in that year, it won the Gordon Bell Prize in the price I performance category. Two large installations—of 8,192 and 12,288 nodes, with a combined peak speed of one teraflops—have been in operation since. QCD-on-a-chip (QCDOC) utilizes a six-dimensional mesh and compute nodes fabricated with IBM system-on-a-chip technology. It offers a tenfold improvement in price/ performance. Currently, 100-node versions are operating, and there are plans to build three 12,288-node, 10-teraflops machines. In this paper, we describe the architecture of both the QCDSP and QCDOC machines, the operating systems employed, the user software environment, and the performance of our application— lattice OCD.
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The state-level distribution of the size of family forest holdings in the contiguous United States was examined using data collected by the USDA Forest Service in 1993 and 2003. Regressions models were used to analyze the factors ...
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The state-level distribution of the size of family forest holdings in the contiguous United States was examined using data collected by the USDA Forest Service in 1993 and 2003. Regressions models were used to analyze the factors influencing the mean size and structural variation among states and between the two periods. Population density, percent of the population at least 65 years of age, percent of the population residing in urban areas, per capita income, income inequality, and per capita private forestland were found to be significantly correlated with the structure of landholding size. This paper suggests that the number and proportion of small-scale family forest owners in the United States are both increasing due to the increasing importance of non-timber amenities to forest landowners.
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The real-time data generated from various smart devices will be released and shared for public to obtain numerous benefits. However, it will lead to individual privacy leakage because of data mining or analysis. Currently, many ex...
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The real-time data generated from various smart devices will be released and shared for public to obtain numerous benefits. However, it will lead to individual privacy leakage because of data mining or analysis. Currently, many existing privacy protection models either fail to be directly applied in real-time data release or are unsatisfactory in terms of data utility and privacy protection. Toward this end, based on m-signature and fuzzy processing, an anonymous privacy protection model, named PMF, is proposed in this paper. Specifically, for the proposed model there are five advantages: 1) PMF defines m-signature for making each bucket with at least m different sensitive values instead of generating any counterfeit tuples, which can not only resist h-difference attack but also improve practical value; 2) the buckets satisfying m-signature are variable over time, and this flexibility of m-signature can improve the efficiency of dynamic update; 3) PMF can effectively insert, delete, and modify real-time data for release; 4) PMF applies fuzzy processing to handle the tuples in the candidate list, which strikes a good balance between the utility of released data and privacy protection; and 5) PMF adopts greedy heuristic algorithm to process update operations, which greatly reduces the information loss of released data. Furthermore, PMF is obviously more secure than the existing models in the real-time data release. Finally, the results of the comparison experiments on real-world and synthetic datasets illustrate that PMF is superior to the existing models in terms of data utility and efficiency.
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Microwave mild hyperthermia and paclitaxel have been reported to be involved in variety of solid tumors. However, rare related researches have been accomplished via directly killing tumor cells using thermochemotherapy. In order t...
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Microwave mild hyperthermia and paclitaxel have been reported to be involved in variety of solid tumors. However, rare related researches have been accomplished via directly killing tumor cells using thermochemotherapy. In order to clarify the potential synergy between microwave-induced hyperthermia at temperatures <41℃ and paclitaxel chemotherapy for inhibiting the growth of the human breast cancer cell line MCF-7, an MTT assay was used. The MCF-7 cells cultured in vitro were treated with paclitaxel alone, treated with microwave-induced hyperthermia for 2 h alone (at 40,40.5 or 41℃), or treated with a combination of paclitaxel and 2 h of hyperthermia (at 40,40.5 or 41℃). Flow cytometry was used to determine the cell apoptosis rate and it was demonstrated that paclitaxel decreased cell viability in a dose-dependent manner. Alone, hyperthermia for 2 h at 41℃ induced apoptosis in MCF-7 cells, to a greater extent compared with hyperthermia for 2 h at 40.0 or 40.5℃ (P<0.05). Together, paclitaxel and 2 h of hyperthermia at 40.5℃ induced significantly increased apoptosis compared with either treatment alone (P<0.05). Increasing the temperature to 41℃ in combination with paclitaxel increased the apoptotic ratio from 12.21±1.02% to 16.36±2.39%. The apoptotic ratio correlated positively with hyperthermia temperature and duration following hyperthermia, as did the synergistic effect obtained by combining hyperthermia and paclitaxel. Notably, the combination of 5 mug/ml paclitaxel and 2 h of hyperthermia at 40℃ enhanced MCF-7 cell proliferation. Mild hyperthermia may exert anti-tumor effects by inducing apoptosis, and combining hyperthermia with paclitaxel synergistically induces apoptosis. Paclitaxel dose and hyperthermia temperature require careful optimization, as low-dose paclitaxel combined with hyperthermia at an insufficient temperature may enhance breast cancer proliferation.
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The existence of the solar tachocline inferred from helioseismology leads to the concept of an interface dynamo. The tachocline, where the strong toroidal magnetic field is generated and stored, is sandwiched between and magnetica...
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The existence of the solar tachocline inferred from helioseismology leads to the concept of an interface dynamo. The tachocline, where the strong toroidal magnetic field is generated and stored, is sandwiched between and magnetically coupled to the radiative interior and the overlying convection zone. We investigate a linear sandwich interface dynamo in Cartesian geometry. The dynamo model consists of four horizontal layers: an electrically conducting layer at -∞ < z < -Δ, a tachocline at -Δ < z < 0, a convection zone at 0 < z < d, and a vacuum exterior at d < z < ∞, where z denotes the vertical coordinate and Δ and d are the thicknesses of the tachocline and convection layer, respectively. The four layers, with different magnetic diffusivities, are magnetically coupled by the three sets of interface-matching conditions for the generated magnetic field. Exact solutions of the coupled dynamo system (the dispersion relation and the generated magnetic field describing growing, horizontally propagating dynamo waves) are obtained. It is shown that the magnetic diffusivities in both the tachocline and radiative interior play an essential role in determining the primary properties of the sandwich interface dynamo. The generated strong toroidal magnetic field is usually concentrated in two different locations: at the top of the tachocline, just below the interface between the tachocline and convection zone, and at the bottom of the tachocline, just above the top of the radiative interior. We find that a reduced magnetic difrusivity in the tachocline or radiative interior has a strong stabilizing effect: a smaller magnetic difrusivity requires a larger magnetic Reynolds number to sustain dynamo action. The relevance of the sandwich interface dynamo to the Sun is also discussed.
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Photothermal excitation based on thermoelastic mechanisms is widely used in non-destructive testing, precision operations, and driving micro-resonators. The narrow drive bandwidth of the high vibration mode in photothermal excitat...
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Photothermal excitation based on thermoelastic mechanisms is widely used in non-destructive testing, precision operations, and driving micro-resonators. The narrow drive bandwidth of the high vibration mode in photothermal excitation limits its application to multi-mode drives. Controlling the laser's irradiation position is an effective solution. In this study, we build a theoretical model to achieve selective and efficient excitation of different flexural vibration modes of beams with different supports. The model can be extended to other thermal and physical boundaries, which is validated by numerical simulations and experimental results. The results show that higher modes with complex periodic shapes can be efficiently excited by focusing the laser at the peak of the absolute value of the second derivative of the flexural mode while focusing the laser at the inflection point of the mode shape will result in extremely small amplitudes. Our study indicates that the thermal gradient plays a vital role in the oscillation of the beam. The conventional view assumes that the resonance of the photo-thermal excitation beam is caused by the local expansion and contraction of the material, which cannot completely explain the dependence principle of the photothermal vibration on the laser irradiation position. To investigate the mechanism of beam resonance under laser excitation, three excitation modes, unidirectional excitation, bidirectional in-phase excitation, and bidirectional anti-phase excitation, were established, and the conversion process of optical energy to mechanical energy under laser excitation was analyzed. These results provide new options for optimal excitation and multi-mode energy flow control in photothermal driving.
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摘要 :Mycoplasma gallisepticum is a significant respiratory and reproductive pathogen of domestic poultry. While the complete genomic sequence of the virulent, low-passage M. gallisepticum strain R (Rlow) has been reported, genomic dete...
展开Mycoplasma gallisepticum is a significant respiratory and reproductive pathogen of domestic poultry. While the complete genomic sequence of the virulent, low-passage M. gallisepticum strain R (Rlow) has been reported, genomic determinants responsible for differences in virulence and host range remain to be completely identified. Here, we utilize genome sequencing and microarray-based comparative genomic data to identify these genomic determinants of virulence and to elucidate genomic variability among strains of M. gallisepticum. Analysis of the high-passage, attenuated derivative of Rlow, Rhigh, indicated that relatively few total genomic changes (64 loci) occurred, yet they are potentially responsible for the observed attenuation of this strain. In addition to previously characterized mutations in cytadherence-related proteins, changes included those in coding sequences of genes involved in sugar metabolism. Analyses of the genome of the M. gallisepticum vaccine strain F revealed numerous differences relative to strain R, including a highly divergent complement of vlhA surface lipoprotein genes, and at least 16 genes absent or significantly fragmented relative to strain R. Notably, an Rlow isogenic mutant in one of these genes (MGA_1107) caused significantly fewer severe tracheal lesions in the natural host compared to virulent M. gallisepticum Rlow. Comparative genomic hybridizations indicated few genetic loci commonly affected in F and vaccine strains ts-11 and 6/85, which would correlate with proteins affecting strain R virulence. Together, these data provide novel insights into inter- and intrastrain M. gallisepticum genomic variability and the genetic basis of M. gallisepticum virulence.
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