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1.
冲江铜矿位于世界三大斑岩成矿域的特提斯-喜马拉雅成矿域,其大地构造位置属冈底斯-念青唐古拉构造带的冈底斯陆缘火山-岩浆弧中部。矿区含矿岩体与非含矿岩体的岩性相同,很难通过肉眼或常规分析方法把它们区分开来。热释光测试结果表明,矿区岩石的热释光曲线有单峰和双峰两种,矿化主要发生在具单峰的似斑状二长花岗岩中。岩石矿化程度越强,热释光总积分强度值越小。另外,高岭土化对岩石天然热释光有叠加作用,具高岭土化的岩石明显具有更高的热释光值,且高岭土化与矿化成负相关。因此,热释光值可作为判断矿化的一个岩石标型。石英粒度统计也表明,含矿岩体的石英粒度曲线呈韵律式变化,而不含矿的岩石粒度曲线呈渐进式变化。故岩石中的石英粒度也可作为矿化的一个矿物标型。 相似文献
2.
Glycerol dialkyl glycerol tetraethers (GDGTs) are increasingly used as proxies for paleoclimate studies of marine and lacustrine environments. While GDGT-based proxies have been applied to a number of lake environments globally, little is known about the distribution of GDGTs on the Qinghai-Tibet Plateau. We have investigated the isoprenoid GDGTs (iGDGTs) and branched GDGTs (bGDGTs) in Lake Qinghai sediments and the surrounding surface soil in order to examine their potential use as paleoclimate proxies on the Qinghai-Tibet Plateau. The results show that (i) the values of the iGDGT/bGDGT ratio for surrounding soil were at the higher end among globally distributed soils and consequently BIT values (avg. 0.71) at the lower end, (ii) the TEX86 values decreased while the MBT and CBT values increased along an onshore soil–nearshore sediment–offshore sediment transect, (iii) the TEX86 values for the offshore sediments were almost identical and their inferred temperatures were close to mean summer surface water temperature and (iv) the bGDGT-inferred mean annual air temperature (MAAT) and pH for soil were consistent with measured MAAT and pH. However, the CBT-inferred pH for offshore sediments seemed inconsistent with the pH of lake water or sediment. Our results suggest that (i) the higher pH may be an important factor leading to the higher iGDGT/bGDGT values (and lower BIT values) in surrounding surface soil, (ii) both iGDGTs and bGDGTs may originate from terrestrial input and in situ production for this saline lake, especially for nearshore sediments. However, for offshore sediments, terrestrial iGDGT input seems minor, and TEX86 may be useful for paleoclimate studies of Lake Qinghai. 相似文献
3.
Claude Jaccard 《Natural Hazards》1990,3(4):329-340
The mutual influence of 21 factors pertaining to terrain, weather, forest and snowpack have been discussed by 10 experts. The semantic (nil, weak, medium, high) evaluations are translated as membership degrees of fuzzy sets, and averaged between the experts by taking their fuzzy expectation value, yielding a 21 × 21 fuzzy matrix for direct interactions. Fuzzy successive multiplications and additions of the matrix give the indirect interactions. The activity and the passivity of the factors with respect to avalanches is represented by directed weighted graphs, and the average semantic values by a 4 × 4 matrix: the activity (passivity) is weak (strong) for tree damage; medium (nil) for altitude; medium (weak) for ground shape; medium (medium) for vegetation, soil, wind, microclimate, tree type, vertical distribution and mechanics of trees, snowpack distribution and snow gliding; strong (nil) for ground inclination and exposition, weather; strong (medium) for heat, precipitation, horizontal distribution of trees, snowpack constitution and stability. 相似文献
4.
Stability analyses for a homogeneous compacted embankment were undertaken considering infiltration of water into the embankment. The analyses include several different practical scenarios: (i) saturated condition, (ii) ponding (or runoff) along with saturated condition, (iii) short term analysis for unsaturated conditions, and (iv) long term analysis for unsaturated conditions. The appropriate shear strength parameters of the compacted soil required for analyzing different practical scenarios were determined using conventional and modified triaxial shear apparatus. The results of the study show that typically shallow circular failures above water front occur due to infiltration rather than the conventional infinite slope type failures. 相似文献
5.
Lithofacies zoning is described for the first time for the Neo- and Eopleistocene of the Bering Sea. Four lithofacies sedimentation zones are distinguished: (I) terrigenous; (II) siliceous–terrigenous; (III) siliceous, and (IV) volcanoterrigenous ones. Corresponding maps were treated using Ronov volumetric method to quantify sedimentation parameters for distinguished lithofacies zones (subzones) and types of Pleistocene sediments. It was revealed that terrigenous sediments predominate over other sediments. Accumulation of the terrigenous sediments was more intense (by 1.4 times) in the Neopleistocene than in the Eopleistocene. The sedimentation rate of siliceous sediments of the Bowers Ridge in the Eopleistocene was two times higher than in the Neopleistocene. 相似文献
6.
超临界流体热力学函数的理论计算 总被引：10，自引：1，他引：9
Ｄｕａｎ等（１９９２。１９９６）基于分子间相互作用势能模型,建立了一个适合于超临界流体的状态方程,此方程能反演出世界上几十个实验室测定的成千上万个纯组分及混合物的ＰＶＴ（压力、体积、温度）数据（温压范围：Ｐ〈２ＧＰａ,Ｔｃ〈Ｔ〈２０００Ｋ）。最近的研究发现,此方程能准确预测Ｈ２Ｏ、ＣＯ２、ＣＨ４、Ｎ２及它们的混合物在Ｔ＝１．３Ｔｃ,Ｐ＝０到Ｔ＝２０００Ｋ,Ｐ＝１０ＧＰａ这一温压范围内的压力、体积、 相似文献
7.
基于大数据、云计算等现代信息技术与理念,结合地质调查工作实际,系统论述了建设地质大数据体系的总体框架和实现的技术途径。提出了地质大数据体系建设的5项任务组成: 建设地质数据采集体系,推进地质数据快速规范采集; 建设地质大数据汇聚体系,实现地质数据快速有效汇聚; 建设地质数据与信息服务产品体系,丰富地质数据与信息社会化服务产品; 建设地质数据与信息服务体系,推进地质数据与信息协同服务; 建设地质大数据支撑平台(“地质云”),提升地质数据与信息服务的能力和水平。论述了5项任务的主要内容及其面临的关键技术问题,并简要提出了建设地质大数据体系对其他相关工作的影响和要求。 相似文献
8.
《International Geology Review》2012,54(2):225-248
We applied our group's previously published multidimensional diagrams in 2006–2012 and corresponding probability estimates in 2011–2012 to geochemical data for Archaean rocks compiled from cratons in Australia, South Africa, Brazil, Canada, and India. Tectonic processes similar to present-day plate tectonics evidently were active at least since the Palaeoarchaean (?3570 Ma). This seems to be true in spite of a presumably hotter Earth at that time. For the eastern part of the Pilbara craton (Australia), a Palaeoarchaean (3570–3450 Ma) and Mesoarchaean (2900 Ma) continental arc setting apparently evolved to a collision (Col) setting during the Neoarchaean (2600 Ma). We infer an island arc (IA) environment for Kambalda (Australia) during the Neoarchaean (2700 Ma). For the Barberton belt (South Africa), a transition from a mid-ocean ridge regime during the older part of the Palaeoarchaean (3470 Ma) to an IA setting during the younger part (3300–3260 Ma) is likely. We inferred an arc environment for the São Francisco craton (Brazil) and the Rio Maria terrane (Brazil) during the Mesoarchaean (3085–2983 Ma and 2870 Ma, respectively), whereas a within-plate setting is clearly indicated for the Carajás metallogenic province (Brazil) during the Neoarchaean (2740–2700 Ma). We also recognize an IA regime for the Mesoarchaean (3000 Ma) North Caribou and Neoarchaean (2700 Ma) Abitibi greenstone belts (Canada), and for the Gadwal greenstone belt (India) during the Neoarchaean (2700–2500 Ma). A Col setting was inferred for the Archaean sanukitoid suite (Canada) and the Kolar suture zone (India) during the Neoarchaean (2700–2660 Ma and 2630–2520 Ma, respectively). 相似文献
9.
Several new multi-dimensional tectonomagmatic discrimination diagrams employing log-ratio variables of chemical elements and probability based procedure have been developed during the last 10 years for basic-ultrabasic, intermediate and acid igneous rocks. There are numerous studies on extensive evaluations of these newly developed diagrams which have indicated their successful application to know the original tectonic setting of younger and older as well as sea-water and hydrothermally altered volcanic rocks. In the present study, these diagrams were applied to Precambrian rocks of Mexico (southern and north-eastern) and Argentina. The study indicated the original tectonic setting of Precambrian rocks from the Oaxaca Complex of southern Mexico as follows: (1) dominant rift (within-plate) setting for rocks of 1117–988 Ma age; (2) dominant rift and less-dominant arc setting for rocks of 1157–1130 Ma age; and (3) a combined tectonic setting of collision and rift for Etla Granitoid Pluton (917 Ma age). The diagrams have indicated the original tectonic setting of the Precambrian rocks from the north-eastern Mexico as: (1) a dominant arc tectonic setting for the rocks of 988 Ma age; and (2) an arc and collision setting for the rocks of 1200–1157 Ma age. Similarly, the diagrams have indicated the dominant original tectonic setting for the Precambrian rocks from Argentina as: (1) with-in plate (continental rift-ocean island) and continental rift (CR) setting for the rocks of 800 Ma and 845 Ma age, respectively; and (2) an arc setting for the rocks of 1174–1169 Ma and of 1212–1188 Ma age. The inferred tectonic setting for these Precambrian rocks are, in general, in accordance to the tectonic setting reported in the literature, though there are some inconsistence inference of tectonic settings by some of the diagrams. The present study confirms the importance of these newly developed discriminant-function based diagrams in inferring the original tectonic setting of Precambrian rocks. 相似文献
10.
Analytical methods used for determining dissolved Fe(II) often yield inaccurate results in the presence of high Fe(III) concentrations. Accurate analysis of Fe(II) in solution when it is less than 1% of the total dissolved Fe concentration (FeT) is sometimes required in both geochemical and environmental studies. For example, such analysis is imperative for obtaining the ratio Fe(II)/Fe(III) in rocks, soils and sediments, for determining the kinetic constants of Fe(II) oxidation in chemical or biochemical systems operating at low pH, and is also important in environmental engineering projects, e.g. for proper control of the regeneration step (oxidation of Fe(II) into Fe(III)) applied in ferric-based gas desulphurization processes. In this work a method capable of yielding accurate Fe(II) concentrations at Fe(II) to FeT ratios as low as 0.05% is presented. The method is based on a pretreatment procedure designed to separate Fe(II) species from Fe(III) species in solution without changing the original Fe(II) concentration. Once separated, a modified phenanthroline method is used to determine the Fe(II) concentration, in the virtual absence of Fe(III) species. The pretreatment procedure consists of pH elevation to pH 4.2–4.65 using NaHCO3 under N2(g) environment, followed by filtration of the solid ferric oxides formed, and subsequent acidification of the Fe(II)-containing filtrate. Accuracy of Fe(II) analyses obtained for samples (Fe(II)/FeT ratios between 2% and 0.05%) to which the described pretreatment was applied was >95%. Elevating pH to above 4.65 during pretreatment was shown to result in a higher error in Fe(II) determination, likely resulting from adsorption of Fe(II) species and their removal from solution with the ferric oxide precipitate. 相似文献
11.
Application of Artificial Intelligence to Maximum Dry Density and Unconfined Compressive Strength of Cement Stabilized Soil 总被引：2，自引：1，他引：1
Sarat Kumar Das Pijush Samui Akshaya K. Sabat 《Geotechnical and Geological Engineering》2011,29(3):329-342
This paper describes two artificial intelligence techniques for prediction of maximum dry density (MDD) and unconfined compressive
strength (UCS) of cement stabilized soil. The first technique uses various artificial neural network (ANN) models such as
Bayesian regularization method (BRNN), Levenberg- Marquardt algorithm (LMNN) and differential evolution algorithm (DENN).
The second technique uses the support vector machine (SVM) that is firmly based on the theory of statistical learning theory,
uses regression technique by introducing ε-insensitive loss function has been adopted. The inputs of both models are liquid
limit (LL), plasticity index (PI), clay fraction (CF)%, sand (S)%, gravel Gr (%), moisture content (MC) and cement content
(Ce). The sensitivity analyses of the input parameters have been also done for both models. Based on different statistical
criteria the SVM models are found to be better than ANN models for the prediction of MDD and UCS of cement stabilized soil. 相似文献
12.
Characteristics of meteorological drought in Bangladesh 总被引：3，自引：3，他引：0
Meteorological drought events occur in Bangladesh are diagnosed using monthly rainfall and mean air temperature from the surface observations and Regional Climate Model (RegCM) by calculating Standardized Precipitation Index (SPI) and Palmer Drought Severity Index (PDSI) for the period 1961?C1990. The historical records of drought event obtained from the Bangladesh Bureau of Statistics and International Disaster Database are used to verify the SPI and PDSI detected events. The SPI and monthly PDSI are obtained for 27 station data across Bangladesh as well as for two subregions over the country. Result based on the observed data shows that regional information is better in drought diagnosis compared to the point information. The regional analysis is able to detect about 80?% of the drought events occurred during the study period. Frequency of moderate drought is higher for all over the country. The SPI calculated from RegCM rainfall shows that the detection of moderate drought events is 10, 7, and 21?% overestimated for 1-, 3-, and 6-month length, respectively, compared to using of observed data. For extreme drought cases, detection is overestimated (underestimated) by 25?% (79?%) for 1-month (6-month) length. The PDSI results for model and observed data are nearly same to SPI calculations. Model monthly PDSI result is overestimated (underestimated) by 29?% (50?%) for moderate (severe) drought events with reference to the observed PDSI. Hence, RegCM output may be useful to detect 3?C6-month (monthly to seasonal) length moderate drought events over a heavy rainfall region likely Bangladesh. 相似文献
13.
Past mining, processing, and waste disposal activities have left a legacy of uranium-contaminated soil and groundwater. Phosphate addition to subsurface environments can potentially immobilize U(VI) in-situ through interactions with uranium at mineral-water interfaces. Phosphate can induce the precipitation of low solubility U(VI)-phosphates, and it may enhance or inhibit U(VI) adsorption to iron(III) (oxy)hydroxide surfaces. Such surfaces may also facilitate the heterogeneous nucleation of U(VI)-phosphate precipitates. The interactions among phosphate, U(VI), and goethite (α-FeOOH) were investigated in a year-long series of experiments at pH 4. Reaction time, total U(VI), total phosphate, and the presence and absence of goethite were systematically varied to determine their effects on the extent of U(VI) uptake and the dominant uranium immobilization mechanism. Dissolved U(VI) and phosphate concentrations were interpreted within a reaction-based modeling framework that included dissolution-precipitation reactions and a surface complexation model to account for adsorption. The best available thermodynamic data and past surface complexation models were integrated to form an internally consistent framework. Additional evidence for the uptake mechanisms was obtained using scanning electron microscopy and X-ray diffraction. The formation and crystal growth of a U(VI)-phosphate phase, most likely chernikovite, UO2HPO4·4H2O(s), occurred rapidly for initially supersaturated suspensions both with and without goethite. Nucleation appears to occur homogeneously for almost all conditions, even in the presence of goethite, but heterogeneous nucleation was likely at one condition. The U(VI)-phosphate solids exhibited metastability depending on the TOTU:TOTP ratio. At the highest phosphate concentration studied (130 μM), U(VI) uptake was enhanced due to the likely formation of a ternary surface complex for low (∼1 μM) to intermediate (∼10 μM) TOTU concentrations and to U(VI)-phosphate precipitation for high TOTU (∼100 μM) concentrations. For conditions favoring precipitation, the goethite surface acted as a sink for dissolved phosphate that resulted in higher dissolved U(VI) concentrations relative to goethite-free conditions. Based on the total uranium and available sorption sites, a critical phosphate concentration between 15 μM and 130 μM was required for preferential precipitation of uranium phosphate over U(VI) adsorption. 相似文献
14.
Zoltan Szabo Vincent T. dePaul Jeffrey M. Fischer Thomas F. Kraemer Eric Jacobsen 《Applied Geochemistry》2012
A total of 1270 raw-water samples (before treatment) were collected from 15 principal and other major aquifer systems (PAs) used for drinking water in 45 states in all major physiographic provinces of the USA and analyzed for concentrations of the Ra isotopes 224Ra, 226Ra and 228Ra establishing the framework for evaluating Ra occurrence. The US Environmental Protection Agency Maximum Contaminant Level (MCL) of 0.185 Bq/L (5 pCi/L) for combined Ra (226Ra plus 228Ra) for drinking water was exceeded in 4.02% (39 of 971) of samples for which both 226Ra and 228Ra were determined, or in 3.15% (40 of 1266) of the samples in which at least one isotope concentration (226Ra or 228Ra) was determined. The maximum concentration of combined Ra was 0.755 Bq/L (20.4 pCi/L) in water from the North Atlantic Coastal Plain quartzose sand aquifer system. All the exceedences of the MCL for combined Ra occurred in water samples from the following 7 PAs (in order of decreasing relative frequency of occurrence): the Midcontinent and Ozark Plateau Cambro-Ordovician dolomites and sandstones, the North Atlantic Coastal Plain, the Floridan, the crystalline rocks (granitic, metamorphic) of New England, the Mesozoic basins of the Appalachian Piedmont, the Gulf Coastal Plain, and the glacial sands and gravels (highest concentrations in New England). 相似文献
15.
A multicellular grade of organization is widely distributed among extant organisms and widely represented in the pre-Ediacaran fossil record. A review of the pre-Ediacaran record identifies nine general categories of multicellular organization: (1) simple clonal colonies; (2) integrated coenobial colonies; (3) simple uniseriate filaments; (4) simple multiseriate filaments; (5) simple coenocytic filaments; (6) branched coenocytic filaments; (7) complex multicellular filaments; (8) complex multicellular vesicles; and (9) problematic macrofossils. A small subset of these fossils can be assigned to extant lineages based on taxonomically diagnostic patterns of cell division, including compelling evidence for chroococcacean, oscillatoriacean and pleurocapsalean cyanobacteria, bangiophycaceaen red algae and hydrodictaceaen green algae. The identification of pre-Ediacaran vaucheriaceaen xanthophyte algae and siphonocladalean green algae is almost as secure, whereas the case for early multicellular nostocalean/stigonematalean cyanobacteria and fungi requires further corroboration; a distinctively patterned acritarch is tentatively identified as an early Neoproterozoic poriferan. Despite this breadth of early multicellular experimentation, there is no evidence for organ-grade differentiation prior to the Ediacaran. Indeed, it is the absence of eumetazoans and embryophytes that distinguishes the pre-Ediacaran world from the fundamentally richer and more dynamic biosphere of the Phanerozoic. 相似文献
16.
Application of Partial Least Squares Regression in Multimodal Integrated Forecasting of Water Vapor and Surface Air Temperature 总被引：1，自引：1，他引：0
The use of a new multi model integration method of Partial Least Squares regression (PLS) can completely eliminate the multicollinearity features to improve multi model’s integrated forecasting results of the humidity and temperature. Based on the four centers’ ensemble forecast results, namely, the European Center for Medium-Range Weather Forecasts (ECMWF), Chinese Meteorological Administration (CMA), the Japan Meteorological Agency (JMA) and the UK Met Office (UKMO), we built a 2012 multi mode (25°~60°N, 60°~150°E) 24 ~168 hours forecast time (interval 24 hours) multi model for humidity and temperature and used the four methods, like ensemble average (BREM) for eliminating the deviation, a simple set of average (EMN), Super Ensemble (SUP) and Partial Least Squares regression (PLS) for ground temperature multi model integration. We used the Root-Mean-Square Error (RMSE) and anomaly correlation coefficient (cor) to determine the effect of more modes of integration and to predict a short course of cold. The two prediction results showed that the Partial Least Squares regression (PLS) was the best multi model integrated method, more superior than the other three single modes and compared with the other three methods, it showed better prediction performance, which has certain value and application prospect. 相似文献
17.
Guidelines are determined for the spatial density and location of climatic variables (temperature and precipitation) that are appropriate for estimating the continental- to hemispheric-scale pattern of atmospheric circulation (sea-level pressure). Because instrumental records of temperature and precipitation simulate the climatic information that is contained in certain paleoenvironmental records (tree-ring, pollen, and written-documentary records, for example), these guidelines provide useful sampling strategies for reconstructing the pattern of atmospheric circulation from paleoenvironmental records. The statistical analysis uses a multiple linear regression model. The sampling strategies consist of changes in site density (from 0.5 to 2.5 sites per million square kilometers) and site location (from western North American sites only to sites in Japan, North America, and western Europe) of the climatic data. The results showed that the accuracy of specification of the pattern of sea-level pressure: (1) is improved if sites with climatic records are spread as uniformly as possible over the area of interest; (2) increases with increasing site density-at least up to the maximum site density used in this study; (3) is improved if sites cover an area that extends considerably beyond the limits of the area of interest. The accuracy of specification was lower for independent data than for the data that were used to develop the regression model; some skill was found for almost all sampling strategies. 相似文献
18.
矿物聚合材料固化过程中的聚合反应机理研究 总被引：15，自引：2，他引：13
以粉煤灰、高岭石等为原料,制备出具有良好力学性能和耐酸性的矿物聚合材料制品,可代替部分硅酸盐水泥制品。根据矿物聚合材料制品在3 d、7 d、14 d、28 d的X射线衍射(XRD)、红外光谱（IR）、扫描电镜（SEM）、核磁共振（NMR）等测试分析结果,研究了该材料固化过程中的聚合反应机理。研究结果表明,矿物聚合材料在固化过程中的反应如下：（1）粉煤灰中的玻璃相在强碱的作用下首先发生溶解,其中部分Si-O、Al-O键发生断裂;（2）断裂之后的Si、Al组分在碱金属离子Na+、OH- 等作用下形成Si、Al低聚体（-Si-O-Na、-Si-O-Ca-OH、Al(OH)-4、Al(OH)2-5、Al(OH)3-6）,而后随着溶液组成和各种离子浓度的变化,这些低聚体形成凝胶状的类沸石前驱体;（3）前驱体脱水形成非晶相物质。核磁共振分析结果表明,28 d制品中,Si的存在方式以Q4为主。研究结果为进一步揭示矿物聚合材料的形成机理、改善制品的性能奠定了良好的基础。 相似文献
19.
微波消解-电感耦合等离子体质谱法测定植物样品中微量元素 总被引：17，自引：7，他引：10
采用过氧化氢-硝酸作溶剂,微波消解样品,外标方法校准,电感耦合等离子体质谱法同时测定植物样品中硼、镉、铜、钴、铬、钼、锂、镍、铅、镧、锗11个微量元素。确定了微波消解仪和等离子体质谱仪的最佳工作参数,研究了有机残留物和共存离子的干扰和消除方法,选择了各元素的测定同位素,以45Sc和103Rh双内标补偿基体效应,建立了样品测定方法。方法检出限(10s)在5~150 ng/g,相对标准偏差(RSD,n=12)在1.27%~5.27%。对多种国家一级生物标准物质进行分析验证,测定值与标准值相符。方法适用于植物的果实、根、茎、叶等不同类型样品中多种微量元素的测定。 相似文献
20.
《地学前缘(英文版)》2020,11(5):1681-1693
From a compilation of geochemical data for the discrimination of the tectonic settings of mid-ocean ridge(MOR;3730 samples) and oceanic plateau(OP;3656 samples),we present two new discriminant functions and diagrams obtained from censored multivariate discordant outlier-free datasets.Ten different sets of data(original concentrations as well as isometric log-ratio transformed(ilr) variables;all 10 major(M) elements as well as all 10 major and 6 trace elements MT) were used to evaluate the quality of discrimination from linear discriminant analysis(LDA) and canonical analysis.Two selected multidimensional models ilrM(9 ilr transformed variables of multi-normally distributed 10 major elements) and ilrMT(15 ilr transformed variables of multi-normally distributed combined 10 major and 6 trace elements),considered as the best or most representative(total of5650 samples for ilr_M and 2858 for ilrMT),provided percent success values,respectively,of 80.9% for the MOR and 81.1% for the OP(ilr_M) and 88.5% for the MOR and 90.1% for the OP(ilrMT).Both processes(log-ratio transformation and multi-normality) rendered the percent success values similar for both groups(MOR and OP).The respective discriminant functions were successfully used for four tests from known tectonic settings and four application cases(two for ophiolites and two for Precambrian rocks),documenting thus the utility of the new discrimination procedure for the MOR and OP tectonic settings.Furthermore,we showed that our multidimensional procedure is robust against analytical errors or uncertainties,as well as post-emplacement compositional changes caused by element mobility from both low or high temperature alteration.The robustness against the gain or loss of a single element at a time was also documented,from which the ilr_(MT) model was evaluated as more robust than the ilr_M model.A new online computer program MOROPdisc was written in Java Framework ZK,which is freely available for use at our web portal http://tlaloc.ier.unam.mx. 相似文献