摘要 :
1. Crystal slag converts to glassy slag as the C/F higher than 2;
2. The mineral transformation can be attributed to the viscosity and critical temperature variation;
3. The structural variation can also be accounted for the visco...
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1. Crystal slag converts to glassy slag as the C/F higher than 2;
2. The mineral transformation can be attributed to the viscosity and critical temperature variation;
3. The structural variation can also be accounted for the viscosity curve conversion.
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摘要 :
1. Crystal slag converts to glassy slag as the C/F higher than 2;
2. The mineral transformation can be attributed to the viscosity and critical temperature variation;
3. The structural variation can also be accounted for the vis...
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1. Crystal slag converts to glassy slag as the C/F higher than 2;
2. The mineral transformation can be attributed to the viscosity and critical temperature variation;
3. The structural variation can also be accounted for the viscosity curve conversion.
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摘要 :
Ionosphere correction model is an important category of methods to tackle the problem of ionosphere delay in GNSS, especially for single-frequency and high-accuracy users. Compared with conventional ionosphere TEC modeling algorit...
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Ionosphere correction model is an important category of methods to tackle the problem of ionosphere delay in GNSS, especially for single-frequency and high-accuracy users. Compared with conventional ionosphere TEC modeling algorithm, direct STEC modeling will avoid the systematic error introduced by the SLM assumption and STEC/VTEC conversion, so as to further improve TEC modeling accuracy. Moreover, in order to take full advantage of both empirical ionosphere model and ionosphere model obtained from GNSS observation data, a new STEC modeling algorithm is proposed in this paper with empirical model adopted as background during STEC inversion from observation data. Therefore, the new algorithm is more robust and reliable in case that there is gross error, data missing, or uneven distribution in GNSS observation data. For validation and evaluation of the new approach, IRI2012 and NeQuick2 are selected as representative background empirical models respectively and observation data from IGS tracking stations are used. Through analysis of the STEC residuals between STEC observation value and computed STEC value from the model, current test results show that the rate of STEC correction is quite satisfactory, about 90% for both IRI and NeQuick2 with the proposed algorithm in this paper. So this approach can serve as a reference for ionosphere product generation in wide-area augmentation systems.
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摘要 :
Ionosphere correction model is an important category of methods to tackle the problem of ionosphere delay in GNSS, especially for single-frequency and high-accuracy users. Compared with conventional ionosphere TEC modeling algorit...
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Ionosphere correction model is an important category of methods to tackle the problem of ionosphere delay in GNSS, especially for single-frequency and high-accuracy users. Compared with conventional ionosphere TEC modeling algorithm, direct STEC modeling will avoid the systematic error introduced by the SLM assumption and STEC/VTEC conversion, so as to further improve TEC modeling accuracy. Moreover, in order to take full advantage of both empirical ionosphere model and ionosphere model obtained from GNSS observation data, a new STEC modeling algorithm is proposed in this paper with empirical model adopted as background during STEC inversion from observation data. Therefore, the new algorithm is more robust and reliable in case that there is gross error, data missing, or uneven distribution in GNSS observation data. For validation and evaluation of the new approach, IRI2012 and NeQuick2 are selected as representative background empirical models respectively and observation data from IGS tracking stations are used. Through analysis of the STEC residuals between STEC observation value and computed STEC value from the model, current test results show that the rate of STEC correction is quite satisfactory, about 90% for both IRI and NeQuick2 with the proposed algorithm in this paper. So this approach can serve as a reference for ionosphere product generation in wide-area augmentation systems.
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The Murray-Darling Basin (MDB) boasts a tremendous diversity of freshwater-dependent species,communities,and ecosystems,all inextricably linked to the highly variable river flows,which create temporal and spatial niches for them t...
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The Murray-Darling Basin (MDB) boasts a tremendous diversity of freshwater-dependent species,communities,and ecosystems,all inextricably linked to the highly variable river flows,which create temporal and spatial niches for them to thrive.However,floodplain ecosystems,including intermittent lakes,swamps,flood runners and floodplain forests and their associated biota have been threatened by river regulation and over-allocation of water resources for consumptive uses,compounded by long term warming and drying trends.In recognising the pivot role of hydrology in the long-term sustainability of these ecosystems,the Australian Governments have implemented a series of numerous water resource policies since the signing of the 1992 Murray-Darling Basin Agreement and the 1994 Council of Australian Governments (COAG) Water Reform,which involved a total investment of AU $25,310 million.These strategies aimed to bring a sustainable and integrated way to manage the increasingly scarce water resources to meet rising demand and growing environmental concerns.However,the ecological outcomes and benefits of the policies are not yet apparent in most aquatic ecosystems; and systematic framework for assessing the ecological benefits of competing watering strategies is needed.In this paper,we present a decision support system,which integrates detailed hydrological modelling and ecological response modelling,to compare alternative water resources management strategies,using Yanga National Park,a large (80,000 ha) important inland floodplain in the MDB,as a case study.The approach has significant advantages,including the following:(1) evaluating management actions is explicit because of relatively tight coupling between impacts on hydrology and ecology; (2) scenarios of over 100 years reveal the realistic climatic and flow variability; (3) ecological impact is represented in the model by a number of aquatic species including vegetation,waterbirds and fish,not just iconic species; (4) the ecological response models are relatively easy to update when new understanding and knowledge emerge.We applied the approach to three water management scenarios,i.e.predevelopment representing the natural condition,current water sharing planbaseline condition,and the proposed Basin Plan.Simulation produced a range of hydrologic conditions and consequent distributions of wetland habitat condition for a number of species,allowing decision makers to compare scenarios.This approach could also be used to assess management actions for optimisation of environment flow delivery.
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摘要 :
The Murray-Darling Basin (MDB) boasts a tremendous diversity of freshwater-dependent species,communities,and ecosystems,all inextricably linked to the highly variable river flows,which create temporal and spatial niches for them t...
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The Murray-Darling Basin (MDB) boasts a tremendous diversity of freshwater-dependent species,communities,and ecosystems,all inextricably linked to the highly variable river flows,which create temporal and spatial niches for them to thrive.However,floodplain ecosystems,including intermittent lakes,swamps,flood runners and floodplain forests and their associated biota have been threatened by river regulation and over-allocation of water resources for consumptive uses,compounded by long term warming and drying trends.In recognising the pivot role of hydrology in the long-term sustainability of these ecosystems,the Australian Governments have implemented a series of numerous water resource policies since the signing of the 1992 Murray-Darling Basin Agreement and the 1994 Council of Australian Governments (COAG) Water Reform,which involved a total investment of AU $25,310 million.These strategies aimed to bring a sustainable and integrated way to manage the increasingly scarce water resources to meet rising demand and growing environmental concerns.However,the ecological outcomes and benefits of the policies are not yet apparent in most aquatic ecosystems; and systematic framework for assessing the ecological benefits of competing watering strategies is needed.In this paper,we present a decision support system,which integrates detailed hydrological modelling and ecological response modelling,to compare alternative water resources management strategies,using Yanga National Park,a large (80,000 ha) important inland floodplain in the MDB,as a case study.The approach has significant advantages,including the following:(1) evaluating management actions is explicit because of relatively tight coupling between impacts on hydrology and ecology; (2) scenarios of over 100 years reveal the realistic climatic and flow variability; (3) ecological impact is represented in the model by a number of aquatic species including vegetation,waterbirds and fish,not just iconic species; (4) the ecological response models are relatively easy to update when new understanding and knowledge emerge.We applied the approach to three water management scenarios,i.e.predevelopment representing the natural condition,current water sharing planbaseline condition,and the proposed Basin Plan.Simulation produced a range of hydrologic conditions and consequent distributions of wetland habitat condition for a number of species,allowing decision makers to compare scenarios.This approach could also be used to assess management actions for optimisation of environment flow delivery.
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The Ailaoshan aquamarine-bearing pegmatites are associated with Proterozoic metamorphic rocks in the southern portion of the Ailaoshan fault-folded complex. The gem-bearing pegmatite mineralization zones of the region occur in are...
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The Ailaoshan aquamarine-bearing pegmatites are associated with Proterozoic metamorphic rocks in the southern portion of the Ailaoshan fault-folded complex. The gem-bearing pegmatite mineralization zones of the region occur in areas generally consistent with the regional tectonic trend. The pegmatites are found in metamorphic rocks, migmatites and in the inner/outer contact zones of gneissoid granites. The Rb-Sr isochron drawn for the pegmatites is 26～31 Ma, (I. E. in Himalayan). The homogenization temperatures of melt and liquid inclusions in minerals vary from 185 to 920℃ , which are comparable to the inclusions observed in banded migmatites and ptygmatic quartz veins in the surrounding metamorphic rocks. The mineralization fluids of the pegmatite were rich in HCO_3 and CO_2, and their compositional assemblages are comparable to metamorphic fluids. Results of H, O, C, Si etc. isotopic analyses and REE, and Be analyses indicates that the sources of mineralization components that formed the pegmatites are closely associated with metamorphic fluids and the enclosing metamorphic rocks. A pegmatite structure simulation experiment was conducted at high temperature and pressure (840℃ and 1,500 × 105Pa. ) , with various metamorphic rock samples in a water-rich and volatile-rich environment. When the liquidus was reached, the temperature was gradually decreased at the rate of 5 ～ 10℃/day over a time period of three months. SEM energy-dispersive spectrum analyses were performed on the experimental products. A series of pegmatoid textures were observed including zonal texture, megacryst texture, drusy cavities, crystal druses, and vesicular texture along with more than ten types of minerals including plagioclase, microcline, quartz and biotite. Different metamorphic rock melts generated different mineral assemblages. Experiment results revealed that the partial melting of metamorphic rocks could form melts similar to pegmatite magmas. Based upon the geological characteristics, geochemistry, and pegmatite texture simulation experimental results, it is concluded that the mineralization components of Ailaoshan aquamarine-bearing pegmatites came from metamorphic rocks. The petrogenetic model for the origin of pegmatites is related to ultrametamorphism and metamorphic anatexis.
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In recent years how to coordinate dual-channel conflict issue has become one of the important topics in the research field of supply chain management. This paper focus on order policy under dual-channel structure with manufacturer...
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In recent years how to coordinate dual-channel conflict issue has become one of the important topics in the research field of supply chain management. This paper focus on order policy under dual-channel structure with manufacturer production capacity constraint and the price-dependent demand environment. By modeling, two models are respectively established to analyze: (1)Stackelberg model in which the manufacturer acts as the leader while the retailer is the follower; (2)the integrated decision with cooperation between manufacturers and retailers, and respectively proved the existence of the optimal in profit. Otherwise, Genetic Algorithm is applied to solve those models. By the results of numerical experiments, some helpful management implication is concluded.
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The statistical problem of estimating the bandwidth parameter of a Gauss-Markov process from a realization of fixed and finite duration T at selectable sampling interval Δ is addressed in this paper. As the observation time, T, i...
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The statistical problem of estimating the bandwidth parameter of a Gauss-Markov process from a realization of fixed and finite duration T at selectable sampling interval Δ is addressed in this paper. As the observation time, T, is fixed and finite, the variance of estimated autocorrelation and continuous-time parameter does not vanish as Δ approaches 0. This necessitates a second order Taylor expansion in deriving the parameter estimator bias and variance, which produces significantly more accurate bias and variance results than a first order one does. Using likelihood ratio methods, we also show that even the large sample distributions of β estimator are better modeled by a gamma than by a normal form. According to the gradient change of the variance, a key result is that three sample regions, which are termed finite, large and very large, corresponding to substantial, gradual, and very slight decrease in variance of the parameter estimator respectively, are quantified. In terms of analysis BW, the three regions are ( — 23, — 35), ( — 35, — 55) and (-55, — ∞) dB. The characterization of the trade off between the variance decrease and sampling rate results in a practical guideline for choosing sampling rate. To demonstrate the practical value of our results, we apply them to the noise prediction problems of a time invariant GM processes. Using moment generating functions, we are able to arrive at explicit and accurate relations between, the set of variables (Δ, T, ?) and m-step prediction performance. In particular, we show that prediction performance is highly robust with respect to estimation accuracy of β. This is significant, in that it allows one to use a surprisingly small observation time, T, and still achieve nearly optimal performance associated with perfect knowledge of β.
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摘要 :
The statistical problem of estimating the bandwidth parameter of a Gauss-Markov process from a realization of fixed and finite duration T at selectable sampling interval Δ is addressed in this paper. As the observation time, T, i...
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The statistical problem of estimating the bandwidth parameter of a Gauss-Markov process from a realization of fixed and finite duration T at selectable sampling interval Δ is addressed in this paper. As the observation time, T, is fixed and finite, the variance of estimated autocorrelation and continuous-time parameter does not vanish as Δ approaches 0. This necessitates a second order Taylor expansion in deriving the parameter estimator bias and variance, which produces significantly more accurate bias and variance results than a first order one does. Using likelihood ratio methods, we also show that even the large sample distributions of β estimator are better modeled by a gamma than by a normal form. According to the gradient change of the variance, a key result is that three sample regions, which are termed finite, large and very large, corresponding to substantial, gradual, and very slight decrease in variance of the parameter estimator respectively, are quantified. In terms of analysis BW, the three regions are ( — 23, — 35), ( — 35, — 55) and (-55, — ∞) dB. The characterization of the trade off between the variance decrease and sampling rate results in a practical guideline for choosing sampling rate. To demonstrate the practical value of our results, we apply them to the noise prediction problems of a time invariant GM processes. Using moment generating functions, we are able to arrive at explicit and accurate relations between, the set of variables (Δ, T, β) and m-step prediction performance. In particular, we show that prediction performance is highly robust with respect to estimation accuracy of β. This is significant, in that it allows one to use a surprisingly small observation time, T, and still achieve nearly optimal performance associated with perfect knowledge of β.
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