Reconstruction of different scales of pore-fractures network of coal reservoir and its permeability prediction with Monte Carlo method

There are millimeter, micron and nanometer scales of pores and fractures in coal to describe different scales of coal pores and fissures communicating path and to quantitatively characterize their permeability. Such information provides an important basis for studying coalbed methane output mechanism. The pores and fissures in a large number of coal samples were observed and counted by scanning electron microscopy and optical microscopy. The probability distribution models of pore-fissure network were then established. Different scales of pore-fissures 2D network models were reconstructed by Monte Carlo method. The 2D seepage models were obtained through assignment zero method and using Matlab software. The effect of permeability on different scale pore-fractures network was obtained by two-dimensional seepage equation. Predicted permeability is compared with the measured ones. The results showed that the dominant order of different scale pore-fractures connected path from high to low is millimeter-sized fractures, seepage pores and micron-size fractures. The contribution of coal reservoir permeability from large to small is millimeter-size fractures, micron-size fractures and seepage pores. Different parameters in different scale pore-fractures are of different influence permeability.Reconstruction of different scale pore-fractures network can clearly display the connectivity of porefractures, which can provide a basis for selecting migration path and studying gas flow pattern.

New results on global exponential stability of competitive neural networks with different time scales and time-varying delays

This paper studies the global exponential stability of competitive neural networks with different time scales and time-varying delays. By using the method of the proper Lyapunov functions and inequality technique, some sufficient conditions are presented for global exponential stability of delay competitive neural networks with different time scales. These conditions obtained have important leading significance in the designs and applications of global exponential stability for competitive neural networks. Finally, an example with its simulation is provided to demonstrate the usefulness of the proposed criteria.

Multi-scales Analysis of Driving Forces on Land Use/Cover Change in China:Taking Farmland Returning to Forest or Grassland as a Case

Increasing populations are causing an increase in food demands, and the area of cultivated land expands every year. Inappropriate land transition from ecology to production results in the constant decline of the ecological security level and influences the regional sustainable development. Adjusting unreasonable land use mode and reconstructing natural land cover are important ways to maintain and improve the ecological environment. Also reclaiming farmland as areas for forests and grasslands (FRFG) is another way. Successful implementation of FRFG in China is the result of comprehensive effect of the multi-scales driving forces. This paper analyses the driving forces of FRFG in China on a national (country) –regional (province) – local (county) – household (farmer) level scale, and the results are: driving forces at the national scale include ecological and food security and the western development of China; at the regional scale, ecological and economic benefits become the main factors to influence the dimension of FRFG under the same policy. The driving forces can be divided into 6 types: industrial structure adjustment, water source protection, flood prevention, the Three-Gorge Project protection, reduction of the amount of sediment flowing into the Yellow River and wind erosion desertification prevention. The driving forces at the local scale can be divided into 12 types with developing leading industries, increasing farmers’ income and improving agricultural production conditions as the main types; at the household scale, the nationalpolicy meeting farmers’ demands and the optimization of individual interests are all driving forces.

INFLUENCE OF DIFFERENT-SCALE ERRORS INTERACTIONS ON ANALYSIS AND FORECAST OF REGIONAL NWP MODEL

In the previous study, the influences of introducing larger- and smaller-scale errors on the background error covariances estimated at the given scales were investigated, respectively. This study used the eovariances obtained in the previous study in the data assimilation and model forecast system based on three-dimensional variational method and the Weather Research and Forecasting model. In this study, analyses and forecasts from this system with different covariances for a period of one month were compared, and the causes for differing results were presented. The varia- tions of analysis increments with different-scale errors are consistent with those of variances and correlations of back- ground errors that were reported in the previous paper. In particular, the introduction of smaller-scale errors leads to greater amplitudes in analysis increments for medium-scale wind at the heights of both high- and low-level jets. Tem- perature and humidity analysis increments are greater at the corresponding scales at the middle- and upper-levels. These analysis increments could improve the intensity of the jet-convection system that includes jets at different levels and the coupling between them that is associated with latent heat release. These changes in analyses will contribute to more ac- curate wind and temperature forecasts in the corresponding areas. When smaller-scale errors are included, humidity analysis increments are significantly enhanced at large scales and lower levels, to moisten southern analyses. Thus, dry bias can be corrected, which will improve humidity forecasts. Moreover, the inclusion of larger- （smaller-） scale errors will be beneficial for the accuracy of forecasts of heavy （light） precipitation at large （small） scales because of the ampli- fication （diminution） of the intensity and area in precipitation forecasts.

Interdecadal Variations of Phase Delays Between Two Nino Indices at Different Time Scales

Phase delays between two Nino indices-sea surface temperatures in Nino regions 1+2 and 3.4 (1950-2001)-at different time scales are detected by wavelet analysis. Analysis results show that there are two types of period bifurcations in the Nino indices and that period bifurcation points exist only in the region where the wavelet power is small. Interdecadal variation features of phase delays between the two indices vary with different time scales. In the periods of 40-72 months, the phase delay changes its sign in 1977: Nino 1+2 indices are 2-4 months earlier than Nino 3.4 indices before 1977, but 3-6 months later afterwards. In the periods of 20-40 months, however, the phase delay changes its sign in another way: Nino 1+2 indices are 1-4 months earlier before 1980 and during 1986-90, but 1-4 months later during 1980-83 and 1993-2001.

Outcome assessment of stroke convalescence using multiple scales based on different dimensions

BACKGROUND: Convalescence is an important stage of stroke treatment. A lot of patients have somatic and mental disorders at various degrees. The primary standard can only reflect partial conditions of somatic disorder; in addition, multiple dimensions of patients at the phase of stroke convalescence are further observed by using a lot of standards, such as signs and symptoms of traditional Chinese medicine, daily activity and psychological status. OBJECTIVE: To analyze the outcome assessments of the cases of stroke convalescence measured with different criteria consisting of various dimensions by a cross-sectional investigation of the condition of stroke convalescent patients. DESIGN: Scale evaluation. SETTING: Departments of Clinical Epidemiology Exploratory Development and Neurology, the Second Affiliated Hospital of Guangzhou University of Traditional Chinese Medicine; National Center for Training of Design, Measurement and Evaluation in Clinical Research,Guangzhou University of Traditional Chinese Medicine. PARTICIPANTS: A total of 194 stroke convalescent patients treated in the Second Affiliated Hospital of Guangzhou University of Traditional Chinese Medicine from July 26, 2000 to February 28, 2001 were taken as subjects of the study. There were 126 males and 68 females aged from 40 to 89 years, and the illness course ranged from 14 to 181 days. All patients met diagnosis-treatment criteria of stroke (the second version)[DTCS(V2.0)] and various kinds of diagnostic points of cerebrovascular diseases; moreover, all patients provided confirmed consents. METHODS: They were assessed by assessment methods including the following assessment instruments: DTCS(V2.0), self-designed scale of traditional Chinese medicine (TCM) symptoms (28 symptoms and physical signs were scored as 0, 1, 2 marks from none to severity), modified Edinburgh-Scandinavia stroke scale (a total of 45 marks, 0 to 15 marks as mild defect, 16 to 30 as moderate defect, 31 to 45 as severe defect), modified Barthel activities of daily life (ADL) index (a total of 100 marks, less than 60 marks as unable self-care), vitality and mental health (subscales derived from Health Survey Questionnaire, SF-36). The collected data from scales and inter-scale correlation were processed by the statistic methods mainly including descriptive analysis, Spearmen correlation analysis, factor analysis, etc. MAIN OUTCOME MEASURES: ① Average scores of scales and criteria; ② correlation between modified Edinburgh-Scandinavia stroke scale and other scales. RESULTS: All of the patients completed the assessment, and analyzed in the final analysis. ① The average scores of the scales and criteria: The average scores of DTCS(V2.0), self-designed scale of TCM symptoms, modified Edinburgh-Scandinavia stroke scale, modified Barthel ADL index, vitality and mental health scales were 6.51±6.29, 13.73±6.97, 7.56±7.35, 63.58±23.68, 52.79±23.32 and 62.83±22.75 respectively. ② Correlation between modified Edinburgh-Scandinavia stroke scale and other scales: The Spearman correlation coefficients (R ’) of modified Edinburgh-Scandinavia stroke scale with diagnosis-treatment criteria of stroke, scales of TCM symptoms, modified Barthel ADL index, vitality scale and mental health scale were 20.885, 0.302, -0.824, -0.294 and -0.258 respectively. CONCLUSION: The modified Edinburgh-Scandinavia stroke scale and DTCS(V2.0) shared the same assessment dimension, so they can be mutually alternated in some clinical practices. Discrepancy in measurements of health status was gained due to the diverse dimensions applied in outcome assessments. It is necessary to build up a multi-dimensional assessment criteria system, such as signs and symptoms, daily activities and psychological status, for assessing the stroke convalescent cases in a more comprehensive scope and reflecting the efficacy of TCM treatment scientifically.

Energy Scaling of Terahertz Pulses Produced through Difference Frequency Generation

We study the energy scaling of terahertz (THz) emission through difference frequency generation of near-infrared pulses, and demonstrate that Gigawatt few-cycle THz transients at the central frequency of 30 THz are produced from GaSe crystal pumped by two pulses at 1.65 and 1.95 micrometers, with the high quantum yield of 28%. Our analysis indicates that the high yield of DFG originates from the largely reduced group velocity mismatch as the long-wavelength pumping pulses are employed.

Analysis of Drought Changes and Drought Mitigation in Xiji County of Ningxia

[Objective] The aim was to study the characteristics of the changes of extreme weather climate incidents such as severe drought in northwest and rainstorm in Xiji County of Ningxia. [Method] Precipitation anomaly percentage was applied to divide drought level and for statistics analysis. Seasonal index, linear tendency, and 5-years gliding average were used to reflect the trend of drought changes. The circulation wave of temporal sequence used polynomial expression to simulate the interannual variation scale. The positive part of the polynomial expression used bar chart to simulate interannual variation scale. [Result] The index of drought season from November to June was large. The general trend of annual drought was increasing. The drought of interannual scale was most serious around 1977, about 15 and 20 years. The drought in recent years went up. The general situation of drought, interannual scale and changes of interannual scales from March to May and from September to October were discussed. Based on the weather at 500 hPa, the first rain in Xiji and the drought-turning-into-rain situation were classified. [Conclusion]These may provide reference value to the prevention and mitigation of drought.

Diagnosis of the Heavy Rain near a Meiyu Front Using the Wet Q Vector Partitioning Method

A heavy rain process of the Changjiang-Huaihe Meiyu front (MYF) is diagnosed by the agency of the traditional Q vector partitioning (QVP) method to decompose the wet Q vector (Q) in a natural coordinate system that follows the isoentropes and by using the numerical simulation results of the revised MM4 meso-scale model. The technique shows that the partitioned wet Q vectors can lead to a significant scale separation of vertical motion related to the torrential rain. The results not only verify the existing conclusion that different scales interact throughout the rainstorm but also indicate the largely different roles of these scales during differing phases of the heavy ramfall on a quantitative basis. Specifically, during the developing stage, the large-scale plays a predominant role in forcing vertical motion, while frontal-scale forcing is secondary; during the intense stage, the frontal-scale evolves into the primary factor of forcing vertical motion, whereas the large-scale forcing is minor and plays a diminishing role and can even be ignored; and during the decaying stage, the large-scale once again serves as the main forcing of vertical motion in such a way that the forcing of the frontal-scale decays quickly and is of secondary importance. Furthermore, the partitioned wet Q vectors are suggested to be more suitable than the total wet Q vector for evaluating the potential physical mechanism of rainstorm genesis. The first step is that the forcing of large-scale $2?bla cdot {? Q}_s^*$ gives rise to the genesis of meso-scale $2?bla cdot {? Q}_n^*$ forcing; and then, accordingly as $2?bla cdot {? Q}_n^*$ forcing increases, whereby the secondary circulation is reinforced, the intensity of the rainfall is strengthened; and at last, the secondary circulation caused by $2?bla cdot {? Q}_n^*$ forcing is directly responsible for generation of the MYF heavy rainfall.

Adaptive projective synchronization with different scaling factors in networks

We study projective synchronization with different scaling factors （PSDF） in N coupled chaotic systems networks. By using the adaptive linear control, some sufficient criteria for the PSDF in symmetrical and asymmetrical coupled networks are separately given based on the Lyapunov function method and the left eigenvalue theory. Numerical simulations for a generalized chaotic unified system are illustrated to verify the theoretical results.

Scaling dependence of memory windows and different carrier charging behaviors in Si nanocrystal nonvolatile memory devices

Based on the charge storage mode,it is important to investigate the scaling dependence of memory performance in silicon nanocrystal（Si-NC） nonvolatile memory（NVM） devices for its scaling down limit.In this work,we made eight kinds of test key cells with different gate widths and lengths by 0.13-μm node complementary metal oxide semiconductor（CMOS） technology.It is found that the memory windows of eight kinds of test key cells are almost the same of about1.64 V @ ±7 V/1 ms,which are independent of the gate area,but mainly determined by the average size（12 nm） and areal density（1.8×10^（11）/cm^2） of Si-NCs.The program/erase（P/E） speed characteristics are almost independent of gate widths and lengths.However,the erase speed is faster than the program speed of test key cells,which is due to the different charging behaviors between electrons and holes during the operation processes.Furthermore,the data retention characteristic is also independent of the gate area.Our findings are useful for further scaling down of Si-NC NVM devices to improve the performance and on-chip integration.

Eye location under different eye poses,scales,and illuminations

Robust non-intrusive eye location plays an important role in vision-based man-mechine interaction. A modified Hausdorff distance based measure to localize the eyes is proposed, which could tolerate various changes in eye pose, shape, and scale. To eliminate the effects of the illumination variations, an 8- neighbour-based transformation of the gray images is proposed. The transformed image is less sensitive to illumination changes while preserves the appearance information of eyes. All the localized candidates of eyes are identified by back-propagation neural networks. Experiments demonstrate that the robust method for eye location is able to localize eyes with different eye sizes, shapes, and poses under different illuminations.

Response of atmospheric circulation to multiscale SST anomaly associated with Kuroshio Extension decadal variability warming in winter

The response of atmospheric circulation to sea surface temperature anomaly(SSTA)of different scales in extratropical oceans has always been a popular issue in air-sea interactions,especially regarding the influence of widely active,small-scale ocean eddies on the atmosphere.Based on the regional climate model RegCM4.6,three sets of ensemble experiments with different initial values were designed,and the response of atmospheric circulation and possible mechanisms to Kuroshio Extension Decadal Variability SSTA with different scales(KEDV-induced SSTA)during winter were discussed.The response of atmospheric circulation to the KEDV-induced mesoscale SSTA presents a broadly tripolar pattern,while the response to the KEDV-induced large-scale SSTA presents a baroclinic structure in the central Pacific and a dipole-type response with a barotropic structure in the eastern Pacific.Further diagnostic analysis shows that under the influence of mesoscale SSTA,transient eddy activity is strengthened,and feedback of transient eddy plays a major role in the large-scale circulation anomaly in the central-eastern Pacific.The associated barotropic energy conversion also plays an important role in maintaining the largescale circulation anomaly in the northwestern Pacific Ocean.Under the influence of large-scale SSTA,diabatic heating is stronger,and the feedback of diabatic heating plays a major role in the large-scale circulation anomaly.

Dynamics of different compound bursting in two phantom bursting mechanism models

The generic phantom bursting model proposed by Bertram et al.can evoke complex bursting oscillations in collaboration with two generic slow variables with different time scales.Two models with the phantom bursting mechanism are suggested,when these two generic slow variables are provided with some specific biological significances by combining slowly varying intracellular Ca2+concentration of the Chay-Keizer electrical bursting model with two different glycolytic oscillations,respectively.Also,complex dynamic behaviors of different compound bursting occurring in these two models are comprehensively surveyed by two fast/slow analyses for a moderately and a slower slow variable,respectively.

Analysis of the Decisions of Farmers Working Different Sized Farms to Constantly Use Soil Testing Formula Fertilizer

This paper researches the behavior of using soil testing formula fertilizer at farms of different sizes.The study develops a probit model based on peasant household survey data from 11 grain production areas.The results prove that：First,obvious differences exist in the distribution of formula fertilizer use ratio among farms of different sizes;large-scale farmers are the highest,small-scale farmers are the lowest.Second,from external factors,the increased yield of corn,soil testing services,and information dissemination,it is clear that training has a significant positive effect on farmers’use behavior;the influence of soil testing services is the greatest.Third the higher the degree of organization,marketization and scale of a farm,the more likely the farmer is to use soil testing formula fertilizer.Policy recommendations are made on the basis of the empirical research presented in this paper.