A－30硬质沥青及其混合料性能试验研究

A－30硬质沥青是指粘稠度相对较大的基质沥青，具有针入度小、粘稠度大、劲度大、软化点高、延度小的特点，其高温性能优良，温度敏感性好，低温性能略差。针对硬质沥青及其混合料的性能指标，尤其是高温性能、低温性能和疲劳性能，同时与石油沥青A－70、SBS改性沥青进行对比试验研究，以全面了解硬质沥青的使用性能，为硬质沥青的应用提供依据，也为夏季炎热地区、重轴截道路和长大纵坡路段的高等级公路沥青路面建设提供参考。     

Energy supply planning in Iran by using fuzzy linear programming approach (regarding uncertainties of investment costs)

For many years, energy models have been used in developed or developing countries to satisfy different needs in energy planning. One of major problems against energy planning and consequently energy models is uncertainty, spread in different economic, political and legal dimensions of energy planning. Confronting uncertainty, energy planners have often used two well-known strategies. The first strategy is stochastic programming, in which energy system planners define different scenarios and apply an explicit probability of occurrence to each scenario. The second strategy is Minimax Regret strategy that minimizes regrets of different decisions made in energy planning. Although these strategies have been used extensively, they could not flexibly and effectively deal with the uncertainties caused by fuzziness. “Fuzzy Linear Programming (FLP)” is a strategy that can take fuzziness into account. This paper tries to demonstrate the method of application of FLP for optimization of supply energy system in Iran, as a case study. The used FLP model comprises fuzzy coefficients for investment costs. Following the mentioned purpose, it is realized that FLP is an easy and flexible approach that can be a serious competitor for other confronting uncertainties approaches, i.e. stochastic and Minimax Regret strategies.     

Explicit incorporation of the energy-band structure into an analysis of the defect chemistry of PbTe and SnTe

A framework is established for the analysis of the defect chemistry of the entire (Pb_1−x Sn _x )_1−y Te _y system based upon statistical thermodynamic calculations and experimentally measured carrier-concentration and tellurium partial-pressure data. The energy-band structure, in which inversion of light-mass, non-parabolic, direct-gap bands occurs and a second, parabolic valence band is present, is explicity incorporated into the analysis for the first time and the usual non-degeneracy assumption is abandoned. The densities of states of the non-ellipsoidal bands and the Fermi levels are calculated numerically. The remaining intrinsic material parameters (the partial pressure of tellurium over intrinsic, pure material and the Schottky constant for doubly-ionized vacancies) are then determined by the fit to the carrier concentration-partial pressure-temperature data. The model established is applied to only PbTe and SnTe because of the lack of partial-pressure data for the ternary solid solutions and satisfactory fits are obtained. The Fermi level lies in the light-mass valence band of SnTe for all of the observed carrier concentrations so that previous analyses of SnTe, which assumed that the hole distribution is non-degenerate, were in error. The 1 at. % wide homogeneity range of SnTe is wide enough that a compositional variation in the sum of the chemical potentials of tin and tellurium has been detected experimentally. This variation is theoretically zero in the usual models for narrow homogeneity-range compounds, but is accounted for in this analysis. Quantitatively satisfactory fits are obtained for PbTe using 0.85mo for the density-of-states effective mass which characterizes the second, parabolic valence band extrema. Only slightly poorer fits are obtained with the roughly established value of 1.0m _o. To obtain good fits for SnTe this mass must be increased from its rough value of 2.0m _o to 2.8m _o; otherwise the partial pressure-temperature curves for fixed compositions within the homogeneity range show too much curvature.     

Multi‐Phase‐Multi‐Size‐Group Model for the Inclusion of Population Balances into the CFD Simulation of Gas‐Liquid Bubbly Flows

A CFD model for the simulation of gas‐liquid bubbly flow is developed. In the model, the multi‐phase flow is simulated by an Eulerian‐Eulerian approach using several phase definitions (from 3 to 10). The bubble size distribution is simulated by a solution of the discretized population balance equation with coalescence and break‐up of bubbles. The number of the discretized population balance equations in the model is larger than the number of the phases used in the flow field simulation. A desired accuracy in the simulation can be achieved by choosing a suitable number of phases as a compromise between accuracy and computational cost. With this model, more detailed flow hydrodynamics and bubble size distribution can be obtained. The model was tested with different operating conditions and for different numbers of dispersed phases in a bubble column, and was verified with a bubble size distribution obtained experimentally.     

Evolution of cost estimating system in China: intelligent estimator for Shandong Province (IES) to general intelligent estimator (GIE)

IES was the first knowledge-based cost estimating system with distinctive Chinese features and has been developed over the past four years, increasing the speed of estimating twelvefold in Shandong Province. GIE, the system for the whole of China is being tested in Jiangsu Province and the authors anticipate that other provinces will adopt the method, thus raising estimating standards in China as a whole. L'IES, developpe au cours des quatre dernieres annees, constitue le premier systeme intelligent d'estimation des couts dote de caracteristiques propres a l'environnement chinois. Son utilisation, dans la province de Shandong, a permis d'accelerer de douze fois la rapidite d'estimation des couts de projets de construction. Les premiers essais du systeme GIE, destine a l'ensemble de la Chine, sont en cours dans la province de Jiangsu. Les auteurs sont convaincus que d'autres provinces adopteront ce systeme, ce qui contribuera a rehausser considerablement l'efficacite des estimations en Chine.     

Corrosion behavior of Mg and Mg-Zn alloys in simulated body fluid

The corrosion behavior of Mg and Mg-Zn in simulated body fluid was studied.The mass loss of pure Mg,Mg-Zn-Zr and Mg-Zn-Zr-Y in simulated body fluid was measured using photovoltaic scale meter.Corrosion rate was determined through electrochemical tests.Finally,the corrosion mechanism was tbermodynamically studied.The results show that the corrosion rate decreases with the lapse of time for both pure Mg and Mg alloys.The purer the alloy,the borer the corrosion resistance exhibits.The corrosion behavior of Mg alloy is improved by the addition of trace Y.     

关于NOAA AVHRR图象重采样及投影方法的研究

本文论述了对极轨气象卫星ＮＯＡＡＡＶＨＲＲ图象进行重采样的必要性，研究了重采样与投影的方法，并利用ＥＲＭａｐｐｅｒ图象处理系统对重采样前后及经过投影处理的彩色图象进行了对比分析。     

Dynamic clustering for acoustic target tracking in wireless sensor networks

We devise and evaluate a fully decentralized, light-weight, dynamic clustering algorithm for target tracking. Instead of assuming the same role for all the sensors, we envision a hierarchical sensor network that is composed of 1) a static backbone of sparsely placed high-capability sensors which assume the role of a cluster head (CH) upon triggered by certain signal events and 2) moderately to densely populated low-end sensors whose function is to provide sensor information to CHs upon request. A cluster is formed and a CH becomes active, when the acoustic signal strength detected by the CH exceeds a predetermined threshold. The active CH then broadcasts an information solicitation packet, asking sensors in its vicinity to join the cluster and provide their sensing information. We address and devise solution approaches (with the use of Voronoi diagram) to realize dynamic clustering: (I1) how CHs operate with one another to ensure that only one CH (preferably the CH that is closes to the target) is active with high probability, (I2) when the active CH solicits for sensor information, instead of having all the sensors in its vicinity reply, only a sufficient number of sensors respond with nonredundant, essential information to determine the target location, and (I3) both the packets that sensors send to their CHs and packets that CHs report to subscribers do not incur significant collision. Through both probabilistic analysis and ns-2 simulation, we use with the use of Voronoi diagram, the CH that is usually closes to the target is (implicitly) selected as the leader and that the proposed dynamic clustering algorithm effectively eliminates contention among sensors and renders more accurate estimates of target locations as a result of better quality data collected and less collision incurred.     

The gamma subunit of the Na,K-ATPase induces cation channel activity

The gamma subunit of the Na,K-ATPase is a hydrophobic protein of approximately 10 kDa. The gamma subunit was expressed in Sf-9 insect cells and Xenopus oocytes to ascertain its role in Na,K-ATPase function. Immunoblotting has shown that the gamma subunit is expressed in Sf-9 cells infected with recombinant baculovirus containing the cDNA for the human gamma subunit. Confocal microscopy demonstrates that the gamma subunit can be delivered to the plasma membrane of Sf-9 cells independently of the other Na,K-ATPase subunits and that gamma colocalizes with alpha1 when these proteins are coexpressed. When Sf-9 cells were coinfected with alpha1 and gamma, antibodies to the gamma subunit were able to coimmunoprecipitate the alpha1 subunit, suggesting that gamma is able to associate with alpha1. The gamma subunit is a member of a family of single-pass transmembrane proteins that induces ion fluxes in Xenopus oocytes. Evidence that the gamma subunit is a functional component was supported by experiments showing gamma-induced cation channel activity when expressed in oocytes and increases in Na+ and K+ uptake when expressed in Sf-9 cells.