Grade-tonnage model is one of the research frontiers of systematical exploration theory. Based on the “Reserve Database of Mineral Resources in China (1997)”, this paper establishes the geological model, grade model...Grade-tonnage model is one of the research frontiers of systematical exploration theory. Based on the “Reserve Database of Mineral Resources in China (1997)”, this paper establishes the geological model, grade model, tonnage model, grade-tonnage model and tonnage-sequence model of contact metasomatic copper deposits in China. The mathematical properties of these models are described in detail.展开更多
A grade-tonnage model is established according to the analysis of 72 porphyry copper deposits recorded in 'The Mineral Resources Data Base of China'. Based on the analysis of frequency histogram, the cumulativ...A grade-tonnage model is established according to the analysis of 72 porphyry copper deposits recorded in 'The Mineral Resources Data Base of China'. Based on the analysis of frequency histogram, the cumulative frequency distributing graph and the theoretical model with double logarithmic coordinates of copper deposits, the typical mathematical characteristics of grade-tonnage model of porphyry copper deposits are clarified.展开更多
This paper presents a hybrid graded element model for the transient heat conduction problem in functionally graded materials （FGMs）. First, a Laplace transform approach is used to handle the time variable. Then, a f...This paper presents a hybrid graded element model for the transient heat conduction problem in functionally graded materials （FGMs）. First, a Laplace transform approach is used to handle the time variable. Then, a fundamental solution in Laplace space for FGMs is constructed. Next, a hybrid graded element is formulated based on the obtained fundamental solution and a frame field. As a result, the graded properties of FGMs are naturally reflected by using the fundamental solution to interpolate the intra-element field. Further, Stefest＇s algorithm is employed to convert the results in Laplace space back into the time-space domain. Finally, the performance of the proposed method is assessed by several benchmark examples. The results demonstrate well the efficiency and accuracy of the proposed method.展开更多
The authors have studied the statistical characteristics of China＇s molybdenum deposits to establish the grade-tonnage model based on the data updated to the end of 2010. The results showed that each type of China＇s...The authors have studied the statistical characteristics of China＇s molybdenum deposits to establish the grade-tonnage model based on the data updated to the end of 2010. The results showed that each type of China＇s molybdenum deposits complied with Lasky＇s law approximately and the characteristics of grade-tonnage model obey the lognormal distribution. However, there are poor correlations between grade and tonnage respectively. Ultimately, we aimed to fit the grade-tonnage model through the known distribution function, draw the cumulative probability curves, and evaluated undiscovered mineral resources of China＇s molybdenum deposits by means of Monte Carlo simulation integrated in MRAS.展开更多
From the process of sedimentation the mathematical relationships among deposition Volume and powder properties as well as sedimentation parameters were deduced. Based on the formula a mathematical model was set up and...From the process of sedimentation the mathematical relationships among deposition Volume and powder properties as well as sedimentation parameters were deduced. Based on the formula a mathematical model was set up and simulated through the computer. At last the validity of mathematical model was supported by the representative experiment on Ti-Mo system FGM prepared by co-sedimentation.展开更多
The Federal Railroad Administration (FRA)’s Web Based Accident Prediction System (WBAPS) is used by federal, state and local agencies to get a preliminary idea on safety at a rail-highway grade crossing. It is an int...The Federal Railroad Administration (FRA)’s Web Based Accident Prediction System (WBAPS) is used by federal, state and local agencies to get a preliminary idea on safety at a rail-highway grade crossing. It is an interactive and user-friendly tool used to make funding decisions. WBAPS is almost three decades old and involves a three-step approach making it difficult to interpret the contribution of the variables included in the model. It also does not directly account for regional/local developments and technological advancements pertaining to signals and signs implemented at rail-highway grade crossings. Further, characteristics of a rail-highway grade crossing vary by track class which is not explicitly considered by WBAPS. This research, therefore, examines and develops a method and models to estimate crashes at rail-highway grade crossings by track class using regional/local level data. The method and models developed for each track class as well as considering all track classes together are based on data for the state of North Carolina. Linear, as well as count models based on Poisson and Negative Binomial (NB) distributions, was tested for applicability. Negative binomial models were found to be the best fit for the data used in this research. Models for each track class have better goodness of fit statistics compared to the model considering data for all track classes together. This is primarily because traffic, design, and operational characteristics at rail-highway grade crossings are different for each track class. The findings from statistical models in this research are supported by model validation.展开更多
Due to the importance of detecting the matte grade in the copper flash smelting process, the mechanism model was established according to the multi-phase and multi-component mathematic model. Meanwhile this procedure ...Due to the importance of detecting the matte grade in the copper flash smelting process, the mechanism model was established according to the multi-phase and multi-component mathematic model. Meanwhile this procedure was a complicated production process with characteristics of large time delay, nonlinearity and so on. A fuzzy neural network model was set up through a great deal of production data. Besides a novel constrained gradient descent algorithm used to update the parameters was put forward to improve the parameters learning efficiency. Ultimately the self-adaptive combination technology was adopted to paralleled integrate two models in order to obtain the prediction model of the matte grade. Industrial data validation shows that the intelligently integrated model is more precise than a single model. It can not only predict the matte grade exactly but also provide optimal control of the copper flash smelting process with potent guidance.展开更多
According to grade-tonnage diagrams of nickel and zinc deposits, their critical grades are 0.4 % and 3. 4 %, respectively, and hence the former resources can be considered optimistic and the latter pessimistic. The gr...According to grade-tonnage diagrams of nickel and zinc deposits, their critical grades are 0.4 % and 3. 4 %, respectively, and hence the former resources can be considered optimistic and the latter pessimistic. The grade-tonnage diagram of gold deposits is convex downwards suggesting that the critical grade is 1 X 10-6 in the low-grade part. The ore value (OV)-tonnage diagram of all deposits In the world consists of three parts: high, middle and low vain f classes. The enrichment ratio (ER)-tonnage diagram of all deposits in the world ho consists of three parts: high, middle and low ratio classes.Nine quality categories defined by ER and OV are characterized by some keywords indicating deposit types as follows: category RH (high ER-high OV: 0. 7 %) by 'unconformity' and 'Mississippi Val-ley', category HM (high ER-middle: OV: 0.7 %) by 'vein', category ML (middle ER-low OV: 0 %) by 'sandstone', 'stockwork' and' dissemination', category LM by 'orthomagmatic',' laterite',komatiite and ' chemical', and category LL by 'porphyry', 'dissemination' and 'placer'. Category MM is not characterized by any keyword. If the commodities of a deposit are defined by both the enrichment ratio and the ore value, the defined commodities are relatively coincident for gold and nickel,but different for copper, silver and zinc, and greatly different for molybdenum and lead. Deposits containing lead and/or zinc are complimentary. If the commodity Ph+Zn is applied, most lead or zinc deposits are classified as Ph+Zu by both definitions. Accessory metals are commonly expected for deposits of kuroko-type zinc, epithermal silver, massive sulfide-type zinc and volcanogenic zinc, but uncommon for deposits of orthomagmatic chromium, chemically precipitated copper and sandstone-type uranium.展开更多
基金National Doctoral Fund Project!(98024004)fund project of the L aboratoryofQuantitativePredictionExploration Assessment
文摘Grade-tonnage model is one of the research frontiers of systematical exploration theory. Based on the “Reserve Database of Mineral Resources in China (1997)”, this paper establishes the geological model, grade model, tonnage model, grade-tonnage model and tonnage-sequence model of contact metasomatic copper deposits in China. The mathematical properties of these models are described in detail.
文摘A grade-tonnage model is established according to the analysis of 72 porphyry copper deposits recorded in 'The Mineral Resources Data Base of China'. Based on the analysis of frequency histogram, the cumulative frequency distributing graph and the theoretical model with double logarithmic coordinates of copper deposits, the typical mathematical characteristics of grade-tonnage model of porphyry copper deposits are clarified.
文摘This paper presents a hybrid graded element model for the transient heat conduction problem in functionally graded materials （FGMs）. First, a Laplace transform approach is used to handle the time variable. Then, a fundamental solution in Laplace space for FGMs is constructed. Next, a hybrid graded element is formulated based on the obtained fundamental solution and a frame field. As a result, the graded properties of FGMs are naturally reflected by using the fundamental solution to interpolate the intra-element field. Further, Stefest＇s algorithm is employed to convert the results in Laplace space back into the time-space domain. Finally, the performance of the proposed method is assessed by several benchmark examples. The results demonstrate well the efficiency and accuracy of the proposed method.
基金funded by the National Natural Science Foundation of China (No.41002119)China Geological Survey (No. 1212010733806)the Basic Scientific Research Funds of the China Central Non-Commercial Institutes (No. K1103)
文摘The authors have studied the statistical characteristics of China＇s molybdenum deposits to establish the grade-tonnage model based on the data updated to the end of 2010. The results showed that each type of China＇s molybdenum deposits complied with Lasky＇s law approximately and the characteristics of grade-tonnage model obey the lognormal distribution. However, there are poor correlations between grade and tonnage respectively. Ultimately, we aimed to fit the grade-tonnage model through the known distribution function, draw the cumulative probability curves, and evaluated undiscovered mineral resources of China＇s molybdenum deposits by means of Monte Carlo simulation integrated in MRAS.
文摘From the process of sedimentation the mathematical relationships among deposition Volume and powder properties as well as sedimentation parameters were deduced. Based on the formula a mathematical model was set up and simulated through the computer. At last the validity of mathematical model was supported by the representative experiment on Ti-Mo system FGM prepared by co-sedimentation.
文摘The Federal Railroad Administration (FRA)’s Web Based Accident Prediction System (WBAPS) is used by federal, state and local agencies to get a preliminary idea on safety at a rail-highway grade crossing. It is an interactive and user-friendly tool used to make funding decisions. WBAPS is almost three decades old and involves a three-step approach making it difficult to interpret the contribution of the variables included in the model. It also does not directly account for regional/local developments and technological advancements pertaining to signals and signs implemented at rail-highway grade crossings. Further, characteristics of a rail-highway grade crossing vary by track class which is not explicitly considered by WBAPS. This research, therefore, examines and develops a method and models to estimate crashes at rail-highway grade crossings by track class using regional/local level data. The method and models developed for each track class as well as considering all track classes together are based on data for the state of North Carolina. Linear, as well as count models based on Poisson and Negative Binomial (NB) distributions, was tested for applicability. Negative binomial models were found to be the best fit for the data used in this research. Models for each track class have better goodness of fit statistics compared to the model considering data for all track classes together. This is primarily because traffic, design, and operational characteristics at rail-highway grade crossings are different for each track class. The findings from statistical models in this research are supported by model validation.
基金Project(60634020) supported by the National Natural Science Foundation of ChinaProject(2002CB312200) supported by the National Basic Research and Development Program of China
文摘Due to the importance of detecting the matte grade in the copper flash smelting process, the mechanism model was established according to the multi-phase and multi-component mathematic model. Meanwhile this procedure was a complicated production process with characteristics of large time delay, nonlinearity and so on. A fuzzy neural network model was set up through a great deal of production data. Besides a novel constrained gradient descent algorithm used to update the parameters was put forward to improve the parameters learning efficiency. Ultimately the self-adaptive combination technology was adopted to paralleled integrate two models in order to obtain the prediction model of the matte grade. Industrial data validation shows that the intelligently integrated model is more precise than a single model. It can not only predict the matte grade exactly but also provide optimal control of the copper flash smelting process with potent guidance.
基金This work is supported by National Natural Science Foundation of China（No.79970025）, Hubei Provincial Department of Education Foundation under Grant No.2003X130, and Scientific Research Team of Wuhan Polytechnic University under Grant No.03-T-06.
基金the Grand-in-Aid for Scientific Research (No. 10041136) from Ministry of Education of Japan.
文摘According to grade-tonnage diagrams of nickel and zinc deposits, their critical grades are 0.4 % and 3. 4 %, respectively, and hence the former resources can be considered optimistic and the latter pessimistic. The grade-tonnage diagram of gold deposits is convex downwards suggesting that the critical grade is 1 X 10-6 in the low-grade part. The ore value (OV)-tonnage diagram of all deposits In the world consists of three parts: high, middle and low vain f classes. The enrichment ratio (ER)-tonnage diagram of all deposits in the world ho consists of three parts: high, middle and low ratio classes.Nine quality categories defined by ER and OV are characterized by some keywords indicating deposit types as follows: category RH (high ER-high OV: 0. 7 %) by 'unconformity' and 'Mississippi Val-ley', category HM (high ER-middle: OV: 0.7 %) by 'vein', category ML (middle ER-low OV: 0 %) by 'sandstone', 'stockwork' and' dissemination', category LM by 'orthomagmatic',' laterite',komatiite and ' chemical', and category LL by 'porphyry', 'dissemination' and 'placer'. Category MM is not characterized by any keyword. If the commodities of a deposit are defined by both the enrichment ratio and the ore value, the defined commodities are relatively coincident for gold and nickel,but different for copper, silver and zinc, and greatly different for molybdenum and lead. Deposits containing lead and/or zinc are complimentary. If the commodity Ph+Zn is applied, most lead or zinc deposits are classified as Ph+Zu by both definitions. Accessory metals are commonly expected for deposits of kuroko-type zinc, epithermal silver, massive sulfide-type zinc and volcanogenic zinc, but uncommon for deposits of orthomagmatic chromium, chemically precipitated copper and sandstone-type uranium.
文摘目的:评估术前牵引对截骨等级的影响,并比较Halo-重力牵引(halo-gravity traction,HGT)和Halo-骨盆牵引(halo-pelvic traction,HPT)在重度脊柱畸形治疗中的疗效差异。方法:回顾性分析2008年8月~2019年11月期间在中山大学附属第三医院接受术前牵引联合后路脊柱截骨融合手术的60例重度脊柱畸形患者的临床资料,其中男性22例,女性38例,年龄8~33岁(19.8±5.9岁),根据术前牵引方式分为HGT组(37例)与HPT(23例)组。分别于牵引前、牵引结束时及术后48个月的脊柱全长X线片上测量矢状面和冠状面Cobb角,并根据节段数计算矢状面畸形角比率(sagittal deformity angular ratio,SDAR)及后凸矫正率,通过截骨等级预测模型评估牵引前后截骨等级变化,并采用逆概率加权(inverse probability of treatment weighting,IPTW)比较两种牵引方式对截骨等级及矫形效果的影响。结果:60例患者均顺利完成治疗,牵引前患者矢状面后凸Cobb角为131.82°±30.29°,冠状面Cobb角为132.70°±28.77°,预测截骨等级为5.10±0.92;牵引结束时,矢状面后凸Cobb角为97.56°±33.54°,冠状面Cobb角为100.93°±30.93°,预测截骨等级为4.14±1.20,较牵引前显著降低(P<0.001),实际截骨等级为4.34±0.98,也较牵引前显著降低(P<0.001)。经IPTW校正后,HGT组矢状面Cobb角由牵引前的133.48°±23.68°降至牵引后111.23°±29.35°,HPT组则由134.96°±40.89°降至75.07°±25.49°。两种牵引方式在降低截骨等级方面无统计学差异(P>0.05),但HPT在改善SDAR方面更具优势(P=0.014),且后凸矫正率优于HGT(P<0.001)。结论:术前HGT和HPT均可有效降低重度脊柱畸形患者所需截骨等级;HPT在改善矢状面畸形相关指标及后凸矫正率方面更具优势。
