This paper reviews the history and lessons of global oil crises while exploring the establishment of a quantitative evaluation model for oil security with Chinese characteristics.Using principal component analysis,it ...This paper reviews the history and lessons of global oil crises while exploring the establishment of a quantitative evaluation model for oil security with Chinese characteristics.Using principal component analysis,it constructs an oil security evaluation indicator system for China with two main-level indicators:foreign oil dependency and its impacts,and market intervention and security assurance.展开更多
0 INTRODUCTION Gas injection refers to the natural gas charging into pre-existing oil reservoirs,which often leads to notable changes in gas-oil ratio(GOR),oil density,and phase states,depending on the pressure-temper...0 INTRODUCTION Gas injection refers to the natural gas charging into pre-existing oil reservoirs,which often leads to notable changes in gas-oil ratio(GOR),oil density,and phase states,depending on the pressure-temperature condition of the reservoirs(Meulbroek et al.,1998;Blanc and Connan,1994;Evans et al.,1971).展开更多
BACKGROUND Endometrial peristalsis(EmP)has been considered as a new indicator for eva-luating endometrial receptivity and is associated with embryo implantation rate and successful pregnancy rate.However,EmP remains u...BACKGROUND Endometrial peristalsis(EmP)has been considered as a new indicator for eva-luating endometrial receptivity and is associated with embryo implantation rate and successful pregnancy rate.However,EmP remains understudied,incon-sistently measured,and poorly understood.New methods are needed urgently for better clinical practice.AIM To explore the value of EmP analysis(EmPA)technique in detecting and analy-zing EmP features automatically and quantitatively.METHODS One hundred and forty-five patients without abnormal findings on conventional transvaginal ultrasound were included in this study.A mid sagittal plane of ute-rus was recorded for 2 minutes in each patient and EmP features were analyzed using EmPA technique.EmP features in 50 patients were also analyzed by naked eyes analysis and the results of two methods were compared.RESULTS EmPA was unsuccessful in 9 patients(9/145,6.21%)due to the interference of respiratory or intestinal movement and was successful in 136 patients(136/145,93.79%),of whom 21 patients showed no EmP and 115 patients underwent EmPA and obtained quantitative results.The results of EmPA technique and naked eyes analysis about EmP intensity and transfer time had no significant consistence.Menstrual cycle,uterine position and history of induced abortion affected the quantitative results of EmPA.CONCLUSION EmPA technique provides noninvasive,quantitative and accurate detection and analysis of EmP in normal population and can evaluate EmP changes associated with menstrual cycle,uterine position and history of induced abortion.展开更多
This work established a quantitative method to access the shear stability of aerobic granular sludge(AGS)and validated its feasibility by using the mature AGS from a pilot-scale(50 tons/day)membrane bioreactor(MBR)for...This work established a quantitative method to access the shear stability of aerobic granular sludge(AGS)and validated its feasibility by using the mature AGS from a pilot-scale(50 tons/day)membrane bioreactor(MBR)for treating real municipal wastewater.The results showed that the changing rate( S)of the peak area(S)of granule size distribution(GSD)exhibited an exponential relationship(R^(2)≥0.76)with the shear time(y=a−b·c^(x)),which was a suitable indicative index to reflect the shear stability of different AGS samples.The limiting granule size(LGS)was defined and proposed to characterize the equilibrium size for AGS after being sheared for a period of time,whose value in terms of Dv50 showed high correlation(R^(2)=0.92)with the parameter a.The free Ca^(2+)(28.44-34.21 mg/L)in the influent specifically interacted with polysaccharides(PS)in the granule’s extracellular polymeric substance(EPS)as a nucleation site,thereby inducing the formation of Ca precipitation to enhance its Young’s modulus,while Ca^(2+) primarily interacted with PS in soluble metabolic product(SMP)during the initial granulation process.Furthermore,the Young’s modulus significantly affected the parameter a related to shear stability(R^(2)=0.99).Since the parameter a was more closely related(R^(2)=1.00)to S than that of the parameter b or c,the excellent correlation(R^(2)=0.99)between the parameter a and the wet density further verified the feasibility of this method.展开更多
A growing number of skin laser treatments have rapidly evolved and increased their role in the field of dermatology,laser treatment is considered to be used for a variety of pigmentary dermatosis as well as aesthetic ...A growing number of skin laser treatments have rapidly evolved and increased their role in the field of dermatology,laser treatment is considered to be used for a variety of pigmentary dermatosis as well as aesthetic problems.The standardized assessment of laser treatment efficacy is crucial for the interpretation and comparison of studies related to laser treatment of skin disorders.In this study,we propose an evaluation method to quantitatively assess laser treatment efficacy based on the image segmentation technology.A tattoo model of Sprague Dawley(SD)rats was established and treated by picosecond laser treatments at varying energy levels.Images of the tattoo models were captured before and after laser treatment,and feature extraction was conducted to quantify the tattooed area and pigment gradation.Subsequently,the clearance rate,which has been a standardized parameter,was calculated.The results indicate that the clearance rates obtained through this quantitative algorithm are comparable and exhibit smaller standard deviations compared with scale scores(4.59%versus 7.93%in the low-energy group,4.01%versus 9.05%in the medium-energy group,and 4.29%versus 10.23%in the high-energy group).This underscores the greater accuracy,objectivity,and reproducibility in assessing treatment responses.The quantitative evaluation of pigment removal holds promise for facilitating faster and more robust assessments in research and development.Additionally,it may enable the optimization of treatments tailored to individual patients,thereby contributing to more effective and personalized dermatological care.展开更多
Blast furnace(BF)operation state was difficult to characterize,measure,and predict.To solve this problem,an intelligent evaluation and advanced prediction method of BF operation state based on industry big data and ma...Blast furnace(BF)operation state was difficult to characterize,measure,and predict.To solve this problem,an intelligent evaluation and advanced prediction method of BF operation state based on industry big data and machine learning was proposed.Based on the criteria of high productivity,low consumption,high quality,smooth running and long life,five BF parameters were extracted according to production experience and metallurgy process.Using the unsupervised learning,a 4-grade evaluation rule was established to realize the intelligent rating of BF operation state.Based on Kendall and maximal information coefficient,70 BF parameters with the most characteristic power of BF operation state were determined.The weights of BF parameters were calculated by applying the criteria importance through intercriteria correlation and the grey correlation degree.The weights of raw material,fuel,gas distribution,cooling stave,BF hearth,and iron and slag were 0.241,0.213,0.140,0.098,0.117 and 0.191,respectively.The weight of data interval was calculated by using the grading algorithm and the monotonicity,and then,the intelligent scoring mechanism based on the multiple weights was formed.It was beneficial to qualitatively and quantitatively characterizing the“black box”BF operation state.Furthermore,combining the algorithm and the evaluation mechanism,a graded prediction model of BF operation state was developed and proposed.It was shown that,compared with the conventional prediction model,the mean absolute error and mean square error of the graded prediction model were reduced by 0.35 and 1.29,respectively,while the explained variation was increased by 14.56%,the hit rate was increased by 5.1%within the error of 3%,and the average hit rate was more than 90.6%.It could be applied to reliably predict the score of BF operation state in the next hour and accurately provide the support for the practical controlling of the running BF.展开更多
Climate change and economic development impact the population expansion and water shortage in the middle reaches of the Yangtze River Basin(MYRB),leading directly to drought aggravation-expansion and impacting agricul...Climate change and economic development impact the population expansion and water shortage in the middle reaches of the Yangtze River Basin(MYRB),leading directly to drought aggravation-expansion and impacting agricultural production in the MYRB.Therefore,this study quantitatively evaluated agricultural drought vulnerability in the MYRB based on the variable fuzzy evaluation model(VFEM).The main conclusions are as follows:(1)The arable land in the MYRB gradually decreased between 2005 and 2020,whereas the forest cover decreased and then increased;(2)precipitation and evapotranspiration were the key factors affecting the agricultural drought vulnerability(e.g.,weights of 0.24 and 0.21),whereas arable land density and gross domestic product(GDP)per capita played less significant roles;and(3)the agricultural drought vulnerability in the MYRB during 2005-2020 was mainly at level 3 and below,with higher drought vulnerability in the western and northern regions,which had a higher drought risk potential.展开更多
The ability of faults to transport oil and gas is affected by multiple geological factors,and the effects of various factors on oil and gas migration and accumulation are complex.In this study,based on the drilling an...The ability of faults to transport oil and gas is affected by multiple geological factors,and the effects of various factors on oil and gas migration and accumulation are complex.In this study,based on the drilling and three-dimensional seismic data in the No.4 structural zone of the Nanpu Sag and by considering the effects of fault throw,caprock thickness,shale content,fluid pressure,stress normal to the fault plane,and brittleness,we employed fault transport index(FTI)to quantitatively characterize the vertical transport ability of regional faults.Through statistical analysis,fault transport probability(N_p)was used to characterize the relationship between FTI and the vertical hydrocarbon content in the formations,The results show that the faults with FTI less than 0.75 cannot transport oil and gas,while those with FTI greater than 2.5 are able to transport oil and gas.Specifically,when FTI is between 0.75and 2.5,there is a functional relationship between the probability of faults transporting hydrocarbons and FTI.The current oil and water distribution and paleo oil reservoir test results indicate that there are oil layers or paleo oil reservoirs in horizons with large N_p.Therefore,FTI can be used as an effective coefficient to indicate the vertical migration paths and accumulation spots of hydrocarbons moving along faults,providing an essential reference for further oil and gas exploration and development.展开更多
The rapid changing near source, multi-stream depositional environment of conglomerate reservoirs leads to severe heterogeneity, complex lithology and physical properties, and large changes of oil layer resistivity. Qu...The rapid changing near source, multi-stream depositional environment of conglomerate reservoirs leads to severe heterogeneity, complex lithology and physical properties, and large changes of oil layer resistivity. Quantitative evaluation of water-flooded layers has become an important but difficult focus for secondary development of oilfields. In this paper, based on the analysis of current problems in quantitative evaluation of water-flooded layers, the Kexia Group conglomerate reservoir of the Sixth District in the Karamay Oilfield was studied. Eight types of conglomerate reservoir lithology were identified effectively by a data mining method combined with the data from sealed coring wells, and then a multi-parameter model for quantitative evaluation of the water-flooded layers of the main oil-bearing lithology was developed. Water production rate, oil saturation and oil productivity index were selected as the characteristic parameters for quantitative evaluation of water-flooded layers of conglomerate reservoirs. Finally, quantitative evaluation criteria and identification rules for water-flooded layers of main oil-bearing lithology formed by integration of the three characteristic parameters of water-flooded layer and undisturbed formation resistivity. This method has been used in evaluation of the water-flooded layers of a conglomerate reservoir in the Karamay Oilfield and achieved good results, improving the interpretation accuracy and compliance rate. It will provide technical support for avoiding perforation of high water-bearing layers and for adjustment of developmental programs.展开更多
Aimed at complex distributed no-fly zones avoidance problems,a novel adaptive lateral reentry guidance algorithm is proposed.Firstly,by introducing the improved attractive and repulsive potential fields,an improved ar...Aimed at complex distributed no-fly zones avoidance problems,a novel adaptive lateral reentry guidance algorithm is proposed.Firstly,by introducing the improved attractive and repulsive potential fields,an improved artificial potential field method is developed.Combined with the proposed judgment criterion for whether a no-fly zone has been avoided,the proposed improved artificial potential field method effectively solves the reference heading angle determination problem under the constraints of complex distributed no-fly zones.Then,based on the proposed no-fly zone’s threat quantitative evaluation method and the reference heading angle determined by the proposed improved artificial potential field method,the heading corridor is improved to increase its sensitivity to the threat changes of the no-fly zones.Finally,for satisfying the requirements of complex distributed no-fly zones avoidance,a novel guidance logic via improved heading corridor is proposed to update the reference heading corridor adaptively in real time according to the threat and constraint changes of the no-fly zones,and the bank reversal logic is employed to control the lateral motion.The simulation results for nominal and dispersed cases indicate that the proposed guidance algorithm has high robustness,stability,and applicability,and is feasible and effective to deal with the complex distributed no-fly zones avoidance problems.展开更多
With the decrease in surface and shallow ore deposits,mineral exploration has focused on deeply buried ore bodies,and large-scale metallogenic prediction presents new opportunities and challenges.This paper adopts the...With the decrease in surface and shallow ore deposits,mineral exploration has focused on deeply buried ore bodies,and large-scale metallogenic prediction presents new opportunities and challenges.This paper adopts the predictive thinking method in this era of big data combined with specific research on the special exploration and exploitation of deep-earth resources.Four basic theoretical models of large-scale deep mineralization prediction and evaluation are explored:mineral prediction geological model theory,multidisciplinary information correlation theory,mineral regional trend analysis theory,and mineral prediction geological differentiation theory.The main workflow of large-scale deep resource prediction in the digital and information age is summarized,including construction of ore prospecting models of metallogenic systems,multiscale 3 D geological modeling,and 3 D quantitative prediction of deep resources.Taking the Lala copper mine in Sichuan Province as an example,this paper carries out deep 3 D quantitative prediction of mineral resources and makes a positive contribution to the future prediction and evaluation of mineral resources.展开更多
The coal strength and deformation properties are key factors affecting safe coal mining and highefficiency coalbed methane(CBM)development.In this paper,reconstituted coal samples are chosen to investigate the weakeni...The coal strength and deformation properties are key factors affecting safe coal mining and highefficiency coalbed methane(CBM)development.In this paper,reconstituted coal samples are chosen to investigate the weakening behavior of gas on coal strength,meanwhile,its effects on coal deformation are quantitatively evaluated.The results indicate that the weakening degree of gas on coal strength is closely related to the confining stress and gas pressure.Compared with non-gas-saturated coals,the maximum weakening ratios of adsorbed gas to coal strength are 10.58%,18.12%,8.55%and 14.65%under the conditions of confining stress CS=3 MPa and gas pressure GP=1 MPa,CS=3 MPa and GP=2 MPa,CS=4 MPa and GP=1 MPa,and CS=4 MPa and GP=2 MPa,respectively.Furthermore,the maximum weakening ratios of free gas to coal strength are 18.27%,36.54%,14.79%and 29.58%,respectively,under above four conditions.The maximum coal bulk strain decreases as particle sizes of coal powders increase,and it has a maximum value of 0.0227 and a minimum value of 0.0191 in particle size ranges of 0.01–0.041 and 0.5–1 mm.Under the same conditions,the coal bulk strain increases with increasing gas pressure,revealing that coal deformation properties can be enhanced by gas.展开更多
In the world,nonalcoholic fatty liver disease(NAFLD)accounts for majority of diffuse hepatic diseases.Notably,substantial liver fat accumulation can trigger and accelerate hepatic fibrosis,thus contributing to disease...In the world,nonalcoholic fatty liver disease(NAFLD)accounts for majority of diffuse hepatic diseases.Notably,substantial liver fat accumulation can trigger and accelerate hepatic fibrosis,thus contributing to disease progression.Moreover,the presence of NAFLD not only puts adverse influences for liver but is also associated with an increased risk of type 2 diabetes and cardiovascular diseases.Therefore,early detection and quantified measurement of hepatic fat content are of great importance.Liver biopsy is currently the most accurate method for the evaluation of hepatic steatosis.However,liver biopsy has several limitations,namely,its invasiveness,sampling error,high cost and moderate intraobserver and interobserver reproducibility.Recently,various quantitative imaging techniques have been developed for the diagnosis and quantified measurement of hepatic fat content,including ultrasound-or magnetic resonancebased methods.These quantitative imaging techniques can provide objective continuous metrics associated with liver fat content and be recorded for comparison when patients receive check-ups to evaluate changes in liver fat content,which is useful for longitudinal follow-up.In this review,we introduce several imaging techniques and describe their diagnostic performance for the diagnosis and quantified measurement of hepatic fat content.展开更多
Using RS and GIS means, this article analyzes the general geological characteristics and the structural belt distribution features in Wenchuan County, Sichuan province, P.R. China as well as the characteristics of the...Using RS and GIS means, this article analyzes the general geological characteristics and the structural belt distribution features in Wenchuan County, Sichuan province, P.R. China as well as the characteristics of the large-scale landslides, mud-rock flows, earthquake lakes, etc., after the earthquake on May 12, 2008. Based on the above work, comprehensive indoor and outdoor research is launched on disaster distribution characteristics and their relationship with earthquakes, terrains, strata, lithology, and structures. Weights of evidence method is utilized to quantitatively analyze and evaluate the spatial distribution of secondary geological disasters after the earthquake occurred. 3 remedying grades for secondary geological disasters are derived from the results of the weights of Evidence, followed by suggestions given to remedy earthquake secondary disasters.展开更多
The quantitative evaluation of multi-process collaborative operation is of great significance for the improvement of production planning and scheduling in steelmaking–continuous casting sections(SCCSs). However, this...The quantitative evaluation of multi-process collaborative operation is of great significance for the improvement of production planning and scheduling in steelmaking–continuous casting sections(SCCSs). However, this evaluation is difficult since it relies on an in-depth understanding of the operating mechanism of SCCSs, and few existing methods can be used to conduct the evaluation, due to the lack of full-scale consideration of the multiple factors related to the production operation. In this study, three quantitative models were developed, and the multiprocess collaborative operation level was evaluated through the laminar-flow operation degree, the process matching degree, and the scheduling strategy availability degree. Based on the evaluation models for the laminar-flow operation and process matching levels, this study investigated the production status of two steelmaking plants, plants A and B, based on actual production data. The average laminar-flow operation(process matching) degrees of SCCSs were obtained as 0.638(0.610) and 1.000(0.759) for plants A and B, respectively, for the period of April to July 2019. Then, a scheduling strategy based on the optimization of the furnace-caster coordinating mode was suggested for plant A. Simulation experiments showed higher availability than the greedy-based and manual strategies. After the proposed scheduling strategy was applied,the average process matching degree of the SCCS of plant A increased by 4.6% for the period of September to November 2019. The multi-process collaborative operation level was improved with fewer adjustments and interruptions in casting.展开更多
Based on a RUSLE model, we identified the key factors of the impact on soil erosion induced by coal min- ing subsidence. We designed a method for predicting/.S factors of a mining subsidence basin, using ana- lytical ...Based on a RUSLE model, we identified the key factors of the impact on soil erosion induced by coal min- ing subsidence. We designed a method for predicting/.S factors of a mining subsidence basin, using ana- lytical GIS spatial technology. Using the Huainan mining area as an example, we calculated the modulus of erosion, its volume and classified the grade of soil erosion for both the original area and the subsidence basin. The results show that the maximum modulus of erosion and the volume of erosion of the subsi- dence basin without water logging would increase by 78% and 23% respectively compared with the ori- ginal situation. The edge of the subsidence basin, where the land subsidence was uneven, is subject to the greatest acceleration in soil erosion. In the situation of water logging after subsidence, the maximum modulus of erosion would decrease if the accumulated slope length were reduced. This maximum mod- ulus around the water logged area within the subsidence basin is equal to that without water logging, while the total volume of erosion decreases. Therefore, mining subsidence aggravates soil erosion espe- cially at the edge of basins where water and soil conservation measures should be taken.展开更多
The scientific analyses of the spatial patterns of regional eco-environment livability,along with the explorations of the correlations between ecoenvironments and population and economic activity distributions,are of ...The scientific analyses of the spatial patterns of regional eco-environment livability,along with the explorations of the correlations between ecoenvironments and population and economic activity distributions,are of major significance in the guidance of the coordinated development between social economies,natural resources,and environments.In this study,the topography,climate,hydrology,land cover,air quality,and the dangers presented by natural hazards in the study area were investigated in order to establish an evaluation model for the regional eco-environmental livability.Then,the observed spatial patterns and regional differences in the eco-environmental livability,as well as their relationships with the distributions of population and economic activities in Zhejiang Province,were investigated.The results showed that the ecoenvironmental livability in Zhejiang Province displayed a gradual decreasing trend from southwest to northeast,as well as from the mountains to the hills,valleys,and plains areas.During the compartmentalization of the eco-environmental livability,it was observed that the lowest livable area covered the largest population,accounting for approximately 29.64%of the total population in the study area.The higher livable areas covered the widest land areas,accounting for approximately 26.15%of the total area.Moreover,it was found that the eco-environmental livability in the mountain areas was higher than that in the plain areas in Zhejiang Province.Furthermore,the ecoenvironmental livability was found to have a significant exponential relationship with the population and GDP densities of Zhejiang Province,with the R^2 of the curve-fittings reaching 0.835 and 0.656,respectively.However,it was determined that the coefficient of the exponential function was negative,which indicated that a strong negative relationship existed between the eco-environmental livability and densities of the population and economic activities.It was assumed that the impacts of anthropogenic factors were the fundamental causes of this negative correlation.This study introduced two new factors(air quality and natural hazards)into the evaluation framework of eco-environmental livability.As a result,a more comprehensive model was established for the evaluation of eco-environmenta livability in certain segments of the study area Additionally,the correlation between ecoenvironment livability and human activities was discussed in-depth,which can potentially provide theoretical and practical guidance for the implementation of eco-livability in China,and possibly even those of other vast developing countries.展开更多
China is implementing the strategy of Rural Revitalization.Revitalizing idle and inefficient utilization courtyards is an important measure for rural revitalization.The evaluation of courtyard utilization efficiency i...China is implementing the strategy of Rural Revitalization.Revitalizing idle and inefficient utilization courtyards is an important measure for rural revitalization.The evaluation of courtyard utilization efficiency is the basis of determining the idle and inefficient utilization courtyards in order to revitalizing it.This study provided a reference for the optimal use of rural courtyard utilization and revitalization through the quantitative comprehensive evaluation of courtyard utilization efficiency and the classification of courtyard utilization types.Taking Shandong Province in Eastern China as study area,we selected eight surveyed villages by stratified sampling method.According to the scale of the villages,full survey and sample survey were used,while middleaged men who familiar with the courtyards were selected as the respondents.Through a household questionnaire survey and face-to-face interviews from2017 to 2018,578 questionnaires of rural courtyardsin eight villages were obtained.Then based on the functions of rural courtyard and land resource conditions,16 comprehensive factors were formulated,involving land conditions,construction conditions and economic benefits,to build the comprehensive evaluation index system of rural courtyard utilization efficiency.Next the index weight was determined by analytic hierarchy process,and the linear weighted regression model was used to evaluate the utilization efficiency of rural courtyard.Finally,the K-means clustering analysis was used to classify the utilization efficiency of courtyards.The results showed that among the eight villages,the average utilization efficiency of courtyards was moderate(one village was low,five were moderate,and two were high).The proportions of both idle and inefficiently utilized courtyards were high.There were three vital factors leading to the idle and low efficiency of rural courtyards.They were declining rural industries,limited arable land per capita,and more farmer workers.In this case,the utilization efficiency of courtyards should be improved by transferring rural land,developing secondary and tertiary industries,evaluating the development potential of villages,classifying and optimizing courtyard utilization,so as to make full use of idle and inefficient courtyards,increase the income of farmers and collectives and promote the revitalization of rural areas.展开更多
Porosity is a major issue in solidification processing of metallic materials.In this work,wedge die casting experiments were designed to investigate the effect of cooling rate on microporosity in an aluminum alloy A35...Porosity is a major issue in solidification processing of metallic materials.In this work,wedge die casting experiments were designed to investigate the effect of cooling rate on microporosity in an aluminum alloy A356.Microstructure information including dendrites and porosity were measured and observed by optical microscopy and X-ray micro-computed tomography(XMCT).The effects of cooling rate on secondary dendrite arm spacing(SDAS)and porosity were discussed.The relationship between SDAS and cooling rate was established and validated using a mathematical model.Three-dimensional(3-D)porosity information,including porosity percentage,pore volume,and pore number,was determined by XMCT.With the cooling rate decreasing from a lower to a higher position of the wedge die,the observed pore number decreases,the porosity percentage increases,and the equivalent pore radius increases.Sphericity of the pores was discussed as an empirical criterion to distinguish the types of porosity.For different cooling rates,the larger the equivalent pore radius is,the lower the sphericity of the pores.This research suggests that XMCT is a useful tool to provide critical 3-D porosity information for integrated computational materials engineering(ICME)design and process optimization of solidification products.展开更多
High resolution image fusion is a significant focus in the field of image processing. A new image fusion model is presented based on the characteristic level of empirical mode decomposition （EMD）. The intensity hue ...High resolution image fusion is a significant focus in the field of image processing. A new image fusion model is presented based on the characteristic level of empirical mode decomposition （EMD）. The intensity hue saturation （IHS） transform of the multi-spectral image first gives the intensity image. Thereafter, the 2D EMD in terms of row-column extension of the 1D EMD model is used to decompose the detailed scale image and coarse scale image from the high-resolution band image and the intensity image. Finally, a fused intensity image is obtained by reconstruction with high frequency of the high-resolution image and low frequency of the intensity image and IHS inverse transform result in the fused image. After presenting the EMD principle, a multi-scale decomposition and reconstruction algorithm of 2D EMD is defined and a fusion technique scheme is advanced based on EMD. Panchromatic band and multi-spectral band 3,2,1 of Quickbird are used to assess the quality of the fusion algorithm. After selecting the appropriate intrinsic mode function （IMF） for the merger on the basis of EMD analysis on specific row （column） pixel gray value series, the fusion scheme gives a fused image, which is compared with generally used fusion algorithms （wavelet, IHS, Brovey）. The objectives of image fusion include enhancing the visibility of the image and improving the spatial resolution and the spectral information of the original images. To assess quality of an image after fusion, information entropy and standard deviation are applied to assess spatial details of the fused images and correlation coefficient, bias index and warping degree for measuring distortion between the original image and fused image in terms of spectral information. For the proposed fusion algorithm, better results are obtained when EMD algorithm is used to perform the fusion experience.展开更多
文摘This paper reviews the history and lessons of global oil crises while exploring the establishment of a quantitative evaluation model for oil security with Chinese characteristics.Using principal component analysis,it constructs an oil security evaluation indicator system for China with two main-level indicators:foreign oil dependency and its impacts,and market intervention and security assurance.
基金supported by the National Natural Science Foundation of China(NSFC)(No.42272169)the efficient exploration and development technologies and integrated demonstration project for deep and ultra-deep carbonate oil and gas reservoirs in the Tarim Basin(No.2025ZD1402301)+1 种基金the Integrated Project of the Joint Fund for Enterprise Innovation and Development of the National Natural Science Foundation of China(No.U24B6001)the Bureau-Level Scientific Research Project of Northwest Oilfield Company(No.KJ202501).
文摘0 INTRODUCTION Gas injection refers to the natural gas charging into pre-existing oil reservoirs,which often leads to notable changes in gas-oil ratio(GOR),oil density,and phase states,depending on the pressure-temperature condition of the reservoirs(Meulbroek et al.,1998;Blanc and Connan,1994;Evans et al.,1971).
基金Supported by Natural Science Foundation of Shanghai,China,No.22ZR1458200Medical PhD Innovative Talent Base Project of Changning District,Shanghai,China,No.RCJD2021B09Key Specialty of Changning District,Shanghai,China,No.20231004.
文摘BACKGROUND Endometrial peristalsis(EmP)has been considered as a new indicator for eva-luating endometrial receptivity and is associated with embryo implantation rate and successful pregnancy rate.However,EmP remains understudied,incon-sistently measured,and poorly understood.New methods are needed urgently for better clinical practice.AIM To explore the value of EmP analysis(EmPA)technique in detecting and analy-zing EmP features automatically and quantitatively.METHODS One hundred and forty-five patients without abnormal findings on conventional transvaginal ultrasound were included in this study.A mid sagittal plane of ute-rus was recorded for 2 minutes in each patient and EmP features were analyzed using EmPA technique.EmP features in 50 patients were also analyzed by naked eyes analysis and the results of two methods were compared.RESULTS EmPA was unsuccessful in 9 patients(9/145,6.21%)due to the interference of respiratory or intestinal movement and was successful in 136 patients(136/145,93.79%),of whom 21 patients showed no EmP and 115 patients underwent EmPA and obtained quantitative results.The results of EmPA technique and naked eyes analysis about EmP intensity and transfer time had no significant consistence.Menstrual cycle,uterine position and history of induced abortion affected the quantitative results of EmPA.CONCLUSION EmPA technique provides noninvasive,quantitative and accurate detection and analysis of EmP in normal population and can evaluate EmP changes associated with menstrual cycle,uterine position and history of induced abortion.
基金supported by the Key Technologies Research and Development Program of Guangzhou (No.2023B03J1284)Guangdong Yuehai Water Investment Co.,Ltd. (No.CC80-QT01-2020-0010).
文摘This work established a quantitative method to access the shear stability of aerobic granular sludge(AGS)and validated its feasibility by using the mature AGS from a pilot-scale(50 tons/day)membrane bioreactor(MBR)for treating real municipal wastewater.The results showed that the changing rate( S)of the peak area(S)of granule size distribution(GSD)exhibited an exponential relationship(R^(2)≥0.76)with the shear time(y=a−b·c^(x)),which was a suitable indicative index to reflect the shear stability of different AGS samples.The limiting granule size(LGS)was defined and proposed to characterize the equilibrium size for AGS after being sheared for a period of time,whose value in terms of Dv50 showed high correlation(R^(2)=0.92)with the parameter a.The free Ca^(2+)(28.44-34.21 mg/L)in the influent specifically interacted with polysaccharides(PS)in the granule’s extracellular polymeric substance(EPS)as a nucleation site,thereby inducing the formation of Ca precipitation to enhance its Young’s modulus,while Ca^(2+) primarily interacted with PS in soluble metabolic product(SMP)during the initial granulation process.Furthermore,the Young’s modulus significantly affected the parameter a related to shear stability(R^(2)=0.99).Since the parameter a was more closely related(R^(2)=1.00)to S than that of the parameter b or c,the excellent correlation(R^(2)=0.99)between the parameter a and the wet density further verified the feasibility of this method.
基金supported by The Shanghai Science and Technology Commission(21S31902700)。
文摘A growing number of skin laser treatments have rapidly evolved and increased their role in the field of dermatology,laser treatment is considered to be used for a variety of pigmentary dermatosis as well as aesthetic problems.The standardized assessment of laser treatment efficacy is crucial for the interpretation and comparison of studies related to laser treatment of skin disorders.In this study,we propose an evaluation method to quantitatively assess laser treatment efficacy based on the image segmentation technology.A tattoo model of Sprague Dawley(SD)rats was established and treated by picosecond laser treatments at varying energy levels.Images of the tattoo models were captured before and after laser treatment,and feature extraction was conducted to quantify the tattooed area and pigment gradation.Subsequently,the clearance rate,which has been a standardized parameter,was calculated.The results indicate that the clearance rates obtained through this quantitative algorithm are comparable and exhibit smaller standard deviations compared with scale scores(4.59%versus 7.93%in the low-energy group,4.01%versus 9.05%in the medium-energy group,and 4.29%versus 10.23%in the high-energy group).This underscores the greater accuracy,objectivity,and reproducibility in assessing treatment responses.The quantitative evaluation of pigment removal holds promise for facilitating faster and more robust assessments in research and development.Additionally,it may enable the optimization of treatments tailored to individual patients,thereby contributing to more effective and personalized dermatological care.
基金supported by the National Natural Science Foundation of China(Nos.52404343,52274326,and 52404341)the Fundamental Research Funds for the Central Universities(N2425031,N25BJD007)+1 种基金the China Postdoctoral Science Foundation(2024M760370)the Liaoning Province Science and Technology Plan Joint Program(Key Research and Development Program Project)(2023JH2/101800058).
文摘Blast furnace(BF)operation state was difficult to characterize,measure,and predict.To solve this problem,an intelligent evaluation and advanced prediction method of BF operation state based on industry big data and machine learning was proposed.Based on the criteria of high productivity,low consumption,high quality,smooth running and long life,five BF parameters were extracted according to production experience and metallurgy process.Using the unsupervised learning,a 4-grade evaluation rule was established to realize the intelligent rating of BF operation state.Based on Kendall and maximal information coefficient,70 BF parameters with the most characteristic power of BF operation state were determined.The weights of BF parameters were calculated by applying the criteria importance through intercriteria correlation and the grey correlation degree.The weights of raw material,fuel,gas distribution,cooling stave,BF hearth,and iron and slag were 0.241,0.213,0.140,0.098,0.117 and 0.191,respectively.The weight of data interval was calculated by using the grading algorithm and the monotonicity,and then,the intelligent scoring mechanism based on the multiple weights was formed.It was beneficial to qualitatively and quantitatively characterizing the“black box”BF operation state.Furthermore,combining the algorithm and the evaluation mechanism,a graded prediction model of BF operation state was developed and proposed.It was shown that,compared with the conventional prediction model,the mean absolute error and mean square error of the graded prediction model were reduced by 0.35 and 1.29,respectively,while the explained variation was increased by 14.56%,the hit rate was increased by 5.1%within the error of 3%,and the average hit rate was more than 90.6%.It could be applied to reliably predict the score of BF operation state in the next hour and accurately provide the support for the practical controlling of the running BF.
基金supported by the Supported by Joint Open Research Fund Program of State Key Laboratory of Hydroscience and Engineering and Tsinghua-Ningxia Yinchuan Joint Institute of Internet of Waters on Digital Water Governance(No.sklhse-2022-Iow04)Open Research Fund of State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin,China Institute of Water Resources and Hydropower Research(No.IWHR-SKL-202217)。
文摘Climate change and economic development impact the population expansion and water shortage in the middle reaches of the Yangtze River Basin(MYRB),leading directly to drought aggravation-expansion and impacting agricultural production in the MYRB.Therefore,this study quantitatively evaluated agricultural drought vulnerability in the MYRB based on the variable fuzzy evaluation model(VFEM).The main conclusions are as follows:(1)The arable land in the MYRB gradually decreased between 2005 and 2020,whereas the forest cover decreased and then increased;(2)precipitation and evapotranspiration were the key factors affecting the agricultural drought vulnerability(e.g.,weights of 0.24 and 0.21),whereas arable land density and gross domestic product(GDP)per capita played less significant roles;and(3)the agricultural drought vulnerability in the MYRB during 2005-2020 was mainly at level 3 and below,with higher drought vulnerability in the western and northern regions,which had a higher drought risk potential.
基金supported by the National Natural Science Foundation of China(Grant Nos.42302150 and U20A2093)National Science and Technology Major Project(Grant No.2024ZD1400104)。
文摘The ability of faults to transport oil and gas is affected by multiple geological factors,and the effects of various factors on oil and gas migration and accumulation are complex.In this study,based on the drilling and three-dimensional seismic data in the No.4 structural zone of the Nanpu Sag and by considering the effects of fault throw,caprock thickness,shale content,fluid pressure,stress normal to the fault plane,and brittleness,we employed fault transport index(FTI)to quantitatively characterize the vertical transport ability of regional faults.Through statistical analysis,fault transport probability(N_p)was used to characterize the relationship between FTI and the vertical hydrocarbon content in the formations,The results show that the faults with FTI less than 0.75 cannot transport oil and gas,while those with FTI greater than 2.5 are able to transport oil and gas.Specifically,when FTI is between 0.75and 2.5,there is a functional relationship between the probability of faults transporting hydrocarbons and FTI.The current oil and water distribution and paleo oil reservoir test results indicate that there are oil layers or paleo oil reservoirs in horizons with large N_p.Therefore,FTI can be used as an effective coefficient to indicate the vertical migration paths and accumulation spots of hydrocarbons moving along faults,providing an essential reference for further oil and gas exploration and development.
文摘The rapid changing near source, multi-stream depositional environment of conglomerate reservoirs leads to severe heterogeneity, complex lithology and physical properties, and large changes of oil layer resistivity. Quantitative evaluation of water-flooded layers has become an important but difficult focus for secondary development of oilfields. In this paper, based on the analysis of current problems in quantitative evaluation of water-flooded layers, the Kexia Group conglomerate reservoir of the Sixth District in the Karamay Oilfield was studied. Eight types of conglomerate reservoir lithology were identified effectively by a data mining method combined with the data from sealed coring wells, and then a multi-parameter model for quantitative evaluation of the water-flooded layers of the main oil-bearing lithology was developed. Water production rate, oil saturation and oil productivity index were selected as the characteristic parameters for quantitative evaluation of water-flooded layers of conglomerate reservoirs. Finally, quantitative evaluation criteria and identification rules for water-flooded layers of main oil-bearing lithology formed by integration of the three characteristic parameters of water-flooded layer and undisturbed formation resistivity. This method has been used in evaluation of the water-flooded layers of a conglomerate reservoir in the Karamay Oilfield and achieved good results, improving the interpretation accuracy and compliance rate. It will provide technical support for avoiding perforation of high water-bearing layers and for adjustment of developmental programs.
基金supported by the National Natural Science Foundation of China(No.12072090)。
文摘Aimed at complex distributed no-fly zones avoidance problems,a novel adaptive lateral reentry guidance algorithm is proposed.Firstly,by introducing the improved attractive and repulsive potential fields,an improved artificial potential field method is developed.Combined with the proposed judgment criterion for whether a no-fly zone has been avoided,the proposed improved artificial potential field method effectively solves the reference heading angle determination problem under the constraints of complex distributed no-fly zones.Then,based on the proposed no-fly zone’s threat quantitative evaluation method and the reference heading angle determined by the proposed improved artificial potential field method,the heading corridor is improved to increase its sensitivity to the threat changes of the no-fly zones.Finally,for satisfying the requirements of complex distributed no-fly zones avoidance,a novel guidance logic via improved heading corridor is proposed to update the reference heading corridor adaptively in real time according to the threat and constraint changes of the no-fly zones,and the bank reversal logic is employed to control the lateral motion.The simulation results for nominal and dispersed cases indicate that the proposed guidance algorithm has high robustness,stability,and applicability,and is feasible and effective to deal with the complex distributed no-fly zones avoidance problems.
基金financially supported by the National Natural Science Foundation of China(No.42002298)the National Key Research and Development Program of China(No.2017YFC0601501)+1 种基金China Geological Survey(No.DD20201181)the Open Research Fund Program of the Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring(Central South University),Ministry of Education(No.2020YSJS09)。
文摘With the decrease in surface and shallow ore deposits,mineral exploration has focused on deeply buried ore bodies,and large-scale metallogenic prediction presents new opportunities and challenges.This paper adopts the predictive thinking method in this era of big data combined with specific research on the special exploration and exploitation of deep-earth resources.Four basic theoretical models of large-scale deep mineralization prediction and evaluation are explored:mineral prediction geological model theory,multidisciplinary information correlation theory,mineral regional trend analysis theory,and mineral prediction geological differentiation theory.The main workflow of large-scale deep resource prediction in the digital and information age is summarized,including construction of ore prospecting models of metallogenic systems,multiscale 3 D geological modeling,and 3 D quantitative prediction of deep resources.Taking the Lala copper mine in Sichuan Province as an example,this paper carries out deep 3 D quantitative prediction of mineral resources and makes a positive contribution to the future prediction and evaluation of mineral resources.
基金financial support from the National Natural Science Foundation of China(Nos.51904310and 51874314)the Fundamental Research Funds for the Central Universities(No.2020YQAQ03)+2 种基金the Open Funds of Key Laboratory of Safety and High-efficiency Coal MiningMinistry of Education(Anhui University of Science and Technology)(No.JYBSYS2019204)the Open Funds of State Key Laboratory Cultivation Base for Gas Geology and Gas Control(Henan Polytechnic University)(No.WS2018B06)。
文摘The coal strength and deformation properties are key factors affecting safe coal mining and highefficiency coalbed methane(CBM)development.In this paper,reconstituted coal samples are chosen to investigate the weakening behavior of gas on coal strength,meanwhile,its effects on coal deformation are quantitatively evaluated.The results indicate that the weakening degree of gas on coal strength is closely related to the confining stress and gas pressure.Compared with non-gas-saturated coals,the maximum weakening ratios of adsorbed gas to coal strength are 10.58%,18.12%,8.55%and 14.65%under the conditions of confining stress CS=3 MPa and gas pressure GP=1 MPa,CS=3 MPa and GP=2 MPa,CS=4 MPa and GP=1 MPa,and CS=4 MPa and GP=2 MPa,respectively.Furthermore,the maximum weakening ratios of free gas to coal strength are 18.27%,36.54%,14.79%and 29.58%,respectively,under above four conditions.The maximum coal bulk strain decreases as particle sizes of coal powders increase,and it has a maximum value of 0.0227 and a minimum value of 0.0191 in particle size ranges of 0.01–0.041 and 0.5–1 mm.Under the same conditions,the coal bulk strain increases with increasing gas pressure,revealing that coal deformation properties can be enhanced by gas.
文摘In the world,nonalcoholic fatty liver disease(NAFLD)accounts for majority of diffuse hepatic diseases.Notably,substantial liver fat accumulation can trigger and accelerate hepatic fibrosis,thus contributing to disease progression.Moreover,the presence of NAFLD not only puts adverse influences for liver but is also associated with an increased risk of type 2 diabetes and cardiovascular diseases.Therefore,early detection and quantified measurement of hepatic fat content are of great importance.Liver biopsy is currently the most accurate method for the evaluation of hepatic steatosis.However,liver biopsy has several limitations,namely,its invasiveness,sampling error,high cost and moderate intraobserver and interobserver reproducibility.Recently,various quantitative imaging techniques have been developed for the diagnosis and quantified measurement of hepatic fat content,including ultrasound-or magnetic resonancebased methods.These quantitative imaging techniques can provide objective continuous metrics associated with liver fat content and be recorded for comparison when patients receive check-ups to evaluate changes in liver fat content,which is useful for longitudinal follow-up.In this review,we introduce several imaging techniques and describe their diagnostic performance for the diagnosis and quantified measurement of hepatic fat content.
基金funded by the National Key Technology R and D Program in the 11th Five year Plan of China(No.2006BAB01A08)
文摘Using RS and GIS means, this article analyzes the general geological characteristics and the structural belt distribution features in Wenchuan County, Sichuan province, P.R. China as well as the characteristics of the large-scale landslides, mud-rock flows, earthquake lakes, etc., after the earthquake on May 12, 2008. Based on the above work, comprehensive indoor and outdoor research is launched on disaster distribution characteristics and their relationship with earthquakes, terrains, strata, lithology, and structures. Weights of evidence method is utilized to quantitatively analyze and evaluate the spatial distribution of secondary geological disasters after the earthquake occurred. 3 remedying grades for secondary geological disasters are derived from the results of the weights of Evidence, followed by suggestions given to remedy earthquake secondary disasters.
基金financially supported by the National Natural Science Foundation of China (Nos.50874014 and 51974023)the Fundamental Research Funds for Central Universities (No.FRF-BR-17-029A)。
文摘The quantitative evaluation of multi-process collaborative operation is of great significance for the improvement of production planning and scheduling in steelmaking–continuous casting sections(SCCSs). However, this evaluation is difficult since it relies on an in-depth understanding of the operating mechanism of SCCSs, and few existing methods can be used to conduct the evaluation, due to the lack of full-scale consideration of the multiple factors related to the production operation. In this study, three quantitative models were developed, and the multiprocess collaborative operation level was evaluated through the laminar-flow operation degree, the process matching degree, and the scheduling strategy availability degree. Based on the evaluation models for the laminar-flow operation and process matching levels, this study investigated the production status of two steelmaking plants, plants A and B, based on actual production data. The average laminar-flow operation(process matching) degrees of SCCSs were obtained as 0.638(0.610) and 1.000(0.759) for plants A and B, respectively, for the period of April to July 2019. Then, a scheduling strategy based on the optimization of the furnace-caster coordinating mode was suggested for plant A. Simulation experiments showed higher availability than the greedy-based and manual strategies. After the proposed scheduling strategy was applied,the average process matching degree of the SCCS of plant A increased by 4.6% for the period of September to November 2019. The multi-process collaborative operation level was improved with fewer adjustments and interruptions in casting.
基金supported by the National Environ-mental Protection Specialized Fund for Commonwealth Industry(No.200809128)the Fundamental Research Funds for the Cen-tral Universities(No.2011RC37)
文摘Based on a RUSLE model, we identified the key factors of the impact on soil erosion induced by coal min- ing subsidence. We designed a method for predicting/.S factors of a mining subsidence basin, using ana- lytical GIS spatial technology. Using the Huainan mining area as an example, we calculated the modulus of erosion, its volume and classified the grade of soil erosion for both the original area and the subsidence basin. The results show that the maximum modulus of erosion and the volume of erosion of the subsi- dence basin without water logging would increase by 78% and 23% respectively compared with the ori- ginal situation. The edge of the subsidence basin, where the land subsidence was uneven, is subject to the greatest acceleration in soil erosion. In the situation of water logging after subsidence, the maximum modulus of erosion would decrease if the accumulated slope length were reduced. This maximum mod- ulus around the water logged area within the subsidence basin is equal to that without water logging, while the total volume of erosion decreases. Therefore, mining subsidence aggravates soil erosion espe- cially at the edge of basins where water and soil conservation measures should be taken.
基金the National Natural Science Foundation of China(No.41901205&41701127)he Natural Science Foundation of Jiangsu Province(No.BK20190482)+1 种基金the Philosophy and Social Science Research Project of Jiangsu University(No.2019SJA0034&2016SJD790012)the Scientific Research Start-up Project of Nanjing University of Science and Technology(No.AE89991/117)。
文摘The scientific analyses of the spatial patterns of regional eco-environment livability,along with the explorations of the correlations between ecoenvironments and population and economic activity distributions,are of major significance in the guidance of the coordinated development between social economies,natural resources,and environments.In this study,the topography,climate,hydrology,land cover,air quality,and the dangers presented by natural hazards in the study area were investigated in order to establish an evaluation model for the regional eco-environmental livability.Then,the observed spatial patterns and regional differences in the eco-environmental livability,as well as their relationships with the distributions of population and economic activities in Zhejiang Province,were investigated.The results showed that the ecoenvironmental livability in Zhejiang Province displayed a gradual decreasing trend from southwest to northeast,as well as from the mountains to the hills,valleys,and plains areas.During the compartmentalization of the eco-environmental livability,it was observed that the lowest livable area covered the largest population,accounting for approximately 29.64%of the total population in the study area.The higher livable areas covered the widest land areas,accounting for approximately 26.15%of the total area.Moreover,it was found that the eco-environmental livability in the mountain areas was higher than that in the plain areas in Zhejiang Province.Furthermore,the ecoenvironmental livability was found to have a significant exponential relationship with the population and GDP densities of Zhejiang Province,with the R^2 of the curve-fittings reaching 0.835 and 0.656,respectively.However,it was determined that the coefficient of the exponential function was negative,which indicated that a strong negative relationship existed between the eco-environmental livability and densities of the population and economic activities.It was assumed that the impacts of anthropogenic factors were the fundamental causes of this negative correlation.This study introduced two new factors(air quality and natural hazards)into the evaluation framework of eco-environmental livability.As a result,a more comprehensive model was established for the evaluation of eco-environmenta livability in certain segments of the study area Additionally,the correlation between ecoenvironment livability and human activities was discussed in-depth,which can potentially provide theoretical and practical guidance for the implementation of eco-livability in China,and possibly even those of other vast developing countries.
文摘China is implementing the strategy of Rural Revitalization.Revitalizing idle and inefficient utilization courtyards is an important measure for rural revitalization.The evaluation of courtyard utilization efficiency is the basis of determining the idle and inefficient utilization courtyards in order to revitalizing it.This study provided a reference for the optimal use of rural courtyard utilization and revitalization through the quantitative comprehensive evaluation of courtyard utilization efficiency and the classification of courtyard utilization types.Taking Shandong Province in Eastern China as study area,we selected eight surveyed villages by stratified sampling method.According to the scale of the villages,full survey and sample survey were used,while middleaged men who familiar with the courtyards were selected as the respondents.Through a household questionnaire survey and face-to-face interviews from2017 to 2018,578 questionnaires of rural courtyardsin eight villages were obtained.Then based on the functions of rural courtyard and land resource conditions,16 comprehensive factors were formulated,involving land conditions,construction conditions and economic benefits,to build the comprehensive evaluation index system of rural courtyard utilization efficiency.Next the index weight was determined by analytic hierarchy process,and the linear weighted regression model was used to evaluate the utilization efficiency of rural courtyard.Finally,the K-means clustering analysis was used to classify the utilization efficiency of courtyards.The results showed that among the eight villages,the average utilization efficiency of courtyards was moderate(one village was low,five were moderate,and two were high).The proportions of both idle and inefficiently utilized courtyards were high.There were three vital factors leading to the idle and low efficiency of rural courtyards.They were declining rural industries,limited arable land per capita,and more farmer workers.In this case,the utilization efficiency of courtyards should be improved by transferring rural land,developing secondary and tertiary industries,evaluating the development potential of villages,classifying and optimizing courtyard utilization,so as to make full use of idle and inefficient courtyards,increase the income of farmers and collectives and promote the revitalization of rural areas.
文摘Porosity is a major issue in solidification processing of metallic materials.In this work,wedge die casting experiments were designed to investigate the effect of cooling rate on microporosity in an aluminum alloy A356.Microstructure information including dendrites and porosity were measured and observed by optical microscopy and X-ray micro-computed tomography(XMCT).The effects of cooling rate on secondary dendrite arm spacing(SDAS)and porosity were discussed.The relationship between SDAS and cooling rate was established and validated using a mathematical model.Three-dimensional(3-D)porosity information,including porosity percentage,pore volume,and pore number,was determined by XMCT.With the cooling rate decreasing from a lower to a higher position of the wedge die,the observed pore number decreases,the porosity percentage increases,and the equivalent pore radius increases.Sphericity of the pores was discussed as an empirical criterion to distinguish the types of porosity.For different cooling rates,the larger the equivalent pore radius is,the lower the sphericity of the pores.This research suggests that XMCT is a useful tool to provide critical 3-D porosity information for integrated computational materials engineering(ICME)design and process optimization of solidification products.
文摘High resolution image fusion is a significant focus in the field of image processing. A new image fusion model is presented based on the characteristic level of empirical mode decomposition （EMD）. The intensity hue saturation （IHS） transform of the multi-spectral image first gives the intensity image. Thereafter, the 2D EMD in terms of row-column extension of the 1D EMD model is used to decompose the detailed scale image and coarse scale image from the high-resolution band image and the intensity image. Finally, a fused intensity image is obtained by reconstruction with high frequency of the high-resolution image and low frequency of the intensity image and IHS inverse transform result in the fused image. After presenting the EMD principle, a multi-scale decomposition and reconstruction algorithm of 2D EMD is defined and a fusion technique scheme is advanced based on EMD. Panchromatic band and multi-spectral band 3,2,1 of Quickbird are used to assess the quality of the fusion algorithm. After selecting the appropriate intrinsic mode function （IMF） for the merger on the basis of EMD analysis on specific row （column） pixel gray value series, the fusion scheme gives a fused image, which is compared with generally used fusion algorithms （wavelet, IHS, Brovey）. The objectives of image fusion include enhancing the visibility of the image and improving the spatial resolution and the spectral information of the original images. To assess quality of an image after fusion, information entropy and standard deviation are applied to assess spatial details of the fused images and correlation coefficient, bias index and warping degree for measuring distortion between the original image and fused image in terms of spectral information. For the proposed fusion algorithm, better results are obtained when EMD algorithm is used to perform the fusion experience.
