“七五”期间数理学部主任基金项目概况

1987年“学部主任基金”设立以来,确实发挥了“取长补短”、“拾遗补缺”作用。本文作者结合自己管理“学部主任基金”的亲身经验,总结并概述了数理科学部“七五”期间“学部主任基金”的几项用途和做法,并就“学部主任基金”的作用、意义发表了很好的见解。但是随着新时期、新形势的变化,随着国家对科学基金投入的不断增加,如何用好“学部主任基金”也越来越应引起我们的注意。我们发表这篇文章,旨在引起各有关方面的深入思考,以最大效益发挥“学部主任基金”的作用,不断发展和完善科学基金制。

Simulation and calculation of internal faults in long-stator linear synchronous motor based on winding function theory

To guarantee the safety of the high speed maglev train system, a novel model based on the winding function theory is proposed for the long-stator linear synchronous motor（LSM）, which is suitable for the real-time calculation of the running state. The accurate coupled mathematical models under different internal fault conditions of the LSM are derived based on the normal model. Then the fault currents and electromagnetic forces are simulated and calculated for the major potential internal faults of the LSM, such as the single-phase short circuit, the phase-phase short circuit and the single-phase open circuit. The characteristic curve between the electromagnetic force and the armature current of the LSM, which is compared with the results from the finite element method, proves the validation of the proposed method. The fault rule is determined and the proposed analytical model also shows its feasibility in the fast fault diagnosis through the comparison of the simulation results of currents and electromagnetic forces under different internal fault types and short circuit ratios.

Local Bifurcation of a Thin Rectangle Plate with the Friction Support Boundary

The dynamical equations of a thin rectangle plate subjected to the friction support boundary and its plane force are established in this paper. The local bifurcation of this system is investigated by using L S method and the singularity theory. The Z 2 bifurcation in non degenerate case is discussed. The local bifurcation diagrams of the unfolding parameters and the bifurcation response characters referred to the physical parameters of the system are obtained by numerical simulation. The results of the computer simulation are coincident with the theoretical analysis and experimental results.

Reflection of thermo-elastic wave in semiconductor nanostructures nonlocal porous medium

The current work is an extension of the nonlocal elasticity theory to fractional order thermo-elasticity in semiconducting nanostructure medium with voids.The analysis is made on the reflection phenomena in context of three-phase-lag thermo-elastic model.It is observed that,four-coupled longitudinal waves and an independent shear vertical wave exist in the medium which is dispersive in nature.It is seen that longitudinal waves are damped,and shear wave is un-damped when angular frequency is less than the cut-off frequency.The voids,thermal and non-local parameter affect the dilatational waves whereas shear wave is only depending upon non-local parameter.It is found that reflection coefficients are affected by nonlocal and fractional order parameters.Reflection coefficients are calculated analytically and computed numerically for a material,silicon and discussed graphically in details.The results for local(classical)theory are obtained as a special case.The study may be useful in semiconductor nanostructure,geology and seismology in addition to semiconductor nanostructure devices.

Parametric modeling of carbon nanotubes and estimating nonlocal constant using simulated vibration signals-ARMA and ANN based approach

Nonlocal continuum mechanics is a popular growing theory for investigating the dynamic behavior of Carbon nanotubes(CNTs).Estimating the nonlocal constant is a crucial step in mathematical modeling of CNTs vibration behavior based on this theory.Accordingly,in this study a vibration-based nonlocal parameter estimation technique,which can be competitive because of its lower instrumentation and data analysis costs,is proposed.To this end,the nonlocal models of the CNT by using the linear and nonlinear theories are established.Then,time response of the CNT to impulsive force is derived by solving the governing equations numerically.By using these time responses the parametric model of the CNT is constructed via the autoregressive moving average(ARMA)method.The appropriate ARMA parameters,which are chosen by an introduced feature reduction technique,are considered features to identify the value of the nonlocal constant.In this regard,a multi-layer perceptron(MLP)network has been trained to construct the complex relation between the ARMA parameters and the nonlocal constant.After training the MLP,based on the assumed linear and nonlinear models,the ability of the proposed method is evaluated and it is shown that the nonlocal parameter can be estimated with high accuracy in the presence/absence of nonlinearity.

Optimum Operating and Regeneration Parameters of ZnI2 Catalyst for Converting Methanol to Triptane:An Ideal Component of Unleaded Aviation Gasoline

Conversion of methanol(MeOH) to 2,2,3-trimethylbutane(triptane) over zinc iodide(ZnI_2)catalyst was investigated in a closed batch reactor.Optimum operating parameters were searched and catalyst deactivation and regeneration behaviors were discussed.The fresh,spent and regenerated catalysts were characterized by XRD,TG and XRF measurements to elucidate the related mechanism.The experimental results showed that the triptane yield reached up to 12.2% under the process conditions,including a reaction temperature of 200℃,an initial pressure of 0.35 MPa,a reaction time of 2 h,and a Me OH to ZnI_2 molar ratio of 2.The catalyst was gradually deactivated after several run cycles.A small amount of iodine was lost and a certain amount of ZnO was formed on the deactivated ZnI_2 catalyst.Deactivation of the catalyst could be attributed to the reduction of ZnI_2 amount,resulted from iodine loss and formation of Zn O.It was firstly pointed out from our work that the deactivated catalyst could be well regenerated by the hydrogen iodide(HI) and the tert-butanol compensation method,wherein the latter was added as an initiator into the reaction system.The activity recovery of the deactivated(spent) catalyst might be related to the reformation of ZnI_2 and acceleration of the initiation step of this reaction.

Variations of Snow Temperature and their Influence on Snow Cover Physical Parameters in the Western Tianshan Mountains,China

This article discussed about snow temperature variations and their impact on snow cover parameters. Automatic temperature recorders were used to sample at lo-minute intervals at the Tianshan Station for Snow-cover and Avalanche Research, Chinese snow temperature Academy of Sciences. lo-layer and the snow cover parameters were measured by the snow property analyzer （Snow Fork） in its Stable period, Interim period and Snow melting period. Results indicate that the amplitude of the diurnal fluctuation in the temperature during Snow melting period is 1.62 times greater than that during Stable period. Time up to the peak temperature at the snow surface lags behind the peak solar radiation by more than 2.5 hours, and lags behind the peak atmospheric temperature by more than 0.2 hours during all three periods. The optimal fitted function of snow temperature profile becomes more complicated from Stable period to Snow melting period. 22 h temperature profiles in Stable period are the optimal fitted by cubic polynomial equation. In Interim period and Snow melting period, temperature profiles are optimal fitted by exponential equation between sunset and sunrise, and by Fourier function when solar radiation is strong. The vertical gradient in the snow temperature reaches its maximum value at the snow surface for three periods. The peak of this maximum value occurs during Stableperiod, and is 4.46 times greater than during Interim period. The absolute value of temperature gradient is lower than 0.1℃ cm-1 for 30 cm beneath snow surface. Snow temperature and temperature gradient in Stable period-Interim period indirectly cause increase （decrease） of snow density mainly by increasing （decreasing） permittivity. While it dramatically increases its water content to change its permittivity and snow density in Snow melting period.

Nonlocal Symmetries to Systems of Nonlinear Diffusion Equations

In this paper, we study potential symmetries to certain systems of nonlinear diffusion equations. Thosesystems have physical applications in soil science, mathematical biology, and invariant curve flows in R^3. Lie point symmetries of the potential system, which cannot be projected to vector fields of the given dependent and independent variables, yield potential symmetries. The class of the system that admits potential symmetries is expanded.

Morphological Research on Geometrical Scattering Waves of an Underwater Target

In this paper, a new method based on morphologic research named reconstruction cross-component removal （RCCR） is developed to analyze geometrical scattering waves of an underwater target. Combining the origin of the cross-component in Wigner-ViUe distribution, the highlight model of target echoes and time-frequency features of linear frequency-modulated signal can remove cross-components produced by multiple component signals in Wigner-Ville distribution and recover the auto-components of output signals. This method is used in experimental data processing, which can strengthen the real geometric highlights, and restrain the cross components. It is demonstrated that this method is helpful to analyze the geometrical scattering waves, providing an effective solution to underwater target detection and recognition.

Local Measurement of Gas-Liquid Bubbly Flow with a Double-Sensor Probe

A double-sensor probe was used to measure local interfacial parameters of a gas-liquid bubbly flow in a horizontal tube. The parameters included void fraction, interfacial concentration, bubble size distribution, bubble frequency and bubble interface velocity. The authors paid special attention to the probe design and construction for minimizing measurement errors. Measures were also taken in the design of sensor ends for preventing corrosions in the flow. This is an effort to improve the current double-sensor probe technique to meet the ever-increasing needs to local parameter measurements in gas-liquid two-phase flows.

Managing Social Performance A Case of Microfinance

Global financial crises might and should be recognized as a potential chance to introduce changes in managing our business, both in financial and other important private and/or public sectors. The prevailing opinion is that a lack of corporative social responsibility is one of the major reasons that lead to global crises occurrence. Nowadays, it is crucial to use the experiences of other industries and sectors which from their very beginning managed to balance finance and social goals at the same time. Microfinance sector is exactly one such sector. This paper is organized as follows： First, we give some overview of different approaches to measuring social performance of microfinance institutions. In this part of the paper we also accent the specifics of microfinance institutions-management within the context of double bottom line. In the second part we focus our analysis on practical implementation of ＂double bottom line management in Prizma MCO, one of the world pioneers in social performance management, by using their revolutionary poverty scorecard system. Then, we analyze how these social performance data are used in decision-making and how it affects overall performance of the organization. The paper is finished with some conclusions and lessons learned.

Convergence Rate of E·B Estimation for Location Parameter Function of One-side Truncated Family Under NA Samples

In this paper, we construct the E·B estimation for parameter function of one-side truncated distribution under NA samples. Also, we obtain its convergence rate at O(n-q), where q is approaching 1/2.

Relocation Selection for Poverty Alleviation:Factor Analysis and GIS Modeling

Resettlement is considered a major policy measure in two major Chinese policy programs,the "Great Development of the West" and poverty alleviation in the new century,and the "New Countryside Development".The selection of the target location of resettlement sites for poverty-stricken villages is of critical importance to the success of resettlement projects,yet the selection process is challenged by the need for analyzing a variety of contributing factors,and the need for many rounds of tedious data processing.So in this paper we present an in-depth analysis of the major factors and data processing model concerning mountainous povertystricken villages,which also takes a major part of China's poor villages.Our analysis shows the following factors bear the most importance in resettlement selection:1) topography:candidate areas should have slope less than 25 degrees and altitude less than 2400 meters.2) accessibility:close to market conventions places and transportation facilities.3) farming resources:with abundant land and water resources.4) non-intrusiveness:interests of receiving villages should be considered and negative impact minimized.A simple measure could be having the candidate area 1000 m away from the receiving residents.5) Minimal ecological and political footprint:candidate areas shall not conflict with nature conservation areas or nationally planned key land use projects.6) Social and cultural compatibility:residents will better off if relocated in the same county,considering language,religion,ethnic culture and other factors.Taking Makuadi,Lushui County of Nujiang Prefecture as a case study,we demonstrate how GIS analysis and modeling tools can be used in the selection process of resettlement projects in mountainous areas.

Seasonal Variability in the Kuroshio Extension Current System

Based on the GDEM hydrographic data with a resolution of 0.5°× 0.5°, the current system (Kuroshio south of Japan and Kuroshio Extension east of Japan) is determined by using the P-Vector Method, and its seasonal variability is investigated. The Kuroshio Meander south of Japan, the two lee-wave meanders in the Kuroshio Extension and the bifurcation of the Kuroshio Extension are properly presented. The path of the Kuroshio Meander, the position of the second (east) meander in the Kuroshio Extension and the bifurcation of the Kuroshio Extension display evident seasonal variation.

New Geophysical Evidences of Fluid Related Features in the Western Ionian Sea-Part I： Advanced Processing of Old Data

In this work, we present the results of processing and interpretation of part of crustal seismic profile MS-24, acquired about 30 years ago. This line is oriented NW-SE and crosses the external front of the Calabrian Arc. In order to better image the complex features that characterize this margin, we applied an advanced seismic processing aiming at defining an accurate velocity field by using iteratively the pre-stack depth migration and theoretical considerations. The reprocessed data give more information about a high amplitude reflector associated to velocity inversion. New re-processed seismic data highlighted the presence of morphological features possibly related to fluid migration, which could explain the relationship between velocity inversion and free gas presence,

Fuzzy Modeling in Environmental Geotechnics

High level of industrialization of northern regions of Russia cause significant pollution problems in the soil. The new approach based on fuzzy modeling for reception and processing of the geocryological information is offered. The technique and methodology of presentation of variables in a logic and linguistic way in a combination to elements of the experimental planning theory is developed. Comparison of the calculated data on model has shown its high adequacy of the experimental data of the various authors. The forecast of geoecological processes in cryolitozone on the basis of the described method will allow increasing reliability of the accepted design decisions.

Research on the Teaching Evaluation System based on Feedback Tracking Technology under Cloud Computing Environment

In this paper, we conduct research on the teaching evaluation system based on the feedback tracking technology under the cloud computing environment. Teaching evaluation is an important work of teaching management department. According to the traditional mode of work, must first into classroom, through questionnaire survey, fill out a form scale, obtain first-hand teaching evaluation data, and then input the data into the computer, after check again the data statistics and analysis which is not efficient. To optimize the procedure, we use the cloud computing to assist finalizing the general evaluation steps which is innovative and meaningful.

Information Interaction Is the Fifth Type of Fundamental Interactions

Information is an integral part of the Universe. By its physical essence information is heterogeneity of matter and energy. Therefore information is inseparably connected with matter and energy. The universal measure of information in physical heterogeneity is the Shannon information entropy. An information approach along with a physical one allows to obtain new, sometimes more general data in relation to data obtained on the ground of physical rules only. The results presented in this paper show the effectiveness of informational approach for studying the interactions in the Universe. The paper shows that, along with the physical interactions the gravitational, electromagnetic, strong, weak interactions exists fifth type of fundamental interactions--information interaction, whose magnitude is not dependent on distance. The existence of information interaction is determined by the entanglement of quantum states, of quantum subsystems. The magnitude of information interaction is measured in bits.

New Geophysical Evidences of Fluid Related Features in the Western Ionian Sea-Part Ⅱ： Data Interpretation

The investigated area is located in the western Ionian Sea, which is an area widely occupied by the external from of the Calabrian Arc. It is characterized by a very rough morphology of the seafloor mainly induced by the thrusting and back-thrusting activity. Such a tectonic regime is extremely favourable for the presence of gas and related fluid migration. New processed line MS-24 and swath-bathymetric data highlighted the presence of positive structures at the seafloor interpreted as mud volcanoes. Along the seismic profile we have also recognized a high amplitude reflector that, although it corresponds to a stratigraphic horizon, it shows an anomalous high amplitude character. The seismic velocity field shows evidences of free gas occurrence and so it cannot be excluded the hypothesis that the high amplitude reflector could be a ＂bottom simulating reflector-BSR＂.