Ⅰ. Exchange Rates Excharge rates are the rates at which currency conversion takes place. They themselves tell us nothing about the relative strength of the currencies involved or economics behind them, It simply refl...Ⅰ. Exchange Rates Excharge rates are the rates at which currency conversion takes place. They themselves tell us nothing about the relative strength of the currencies involved or economics behind them, It simply reflects the difference between the denominations into which the two countries have chosen to divide their respective currencies. A currency is considered externally weak if the government is having difficulty maintaining the predetermined exchange rates under展开更多
To obtain the influence laws of the fine gangue rate on the properties of coal gangue cementitious paste, the slump, divergence, stratification, bleeding, setting time and mechanical strength with the change of fine g...To obtain the influence laws of the fine gangue rate on the properties of coal gangue cementitious paste, the slump, divergence, stratification, bleeding, setting time and mechanical strength with the change of fine gangue rate were studied on the basis of keeping the amount of cementing material and slurry concentration unchanged. The porosity and the distribution of pore diameter of the filling specimen for curing 28 d were tested by a mercury injection instrument under different fine gangue rate conditions. It was shown that the slump, divergence, setting time and compressive strength of the paste firstly increased and then decreased with increasing fine gangue rate. The stratification and bleeding rate decreased with increasing fine gangue rate. The smaller the critical pore size of the paste was, the smaller the porosity was, the smaller the average pore size was. When the fine gangue rate was 40%, the maximum critical pore diameter of the paste was 55.79 μm, and the corresponding porosity was 17.54%, and the properties of filling paste were the best. When the fine gangue rate further increased, the aggregate surface area increased, and the reaction product of cementitious materials could not effectively fill the pores. It weakened the agglomeration effect. The particles surface of coal gangue was fragmental and flake deposit with irregular shape and uneven fold morphology. It was easy to be bonded with the surface of other filling material. The hydration products of coal gangue cementitious material were a large number of C-S-H gel with fibrous shape and ettringite(AFt) with compact block structure. The theoretical reference was provided for the preparation of low cost gangue cemented filling materials in coal mines.展开更多
Fault fracture zones and water-bearing bodies in front of the driving head are the main disasters in mine laneways,thus it is important to perform their advanced detection and prediction in advance in order to provide...Fault fracture zones and water-bearing bodies in front of the driving head are the main disasters in mine laneways,thus it is important to perform their advanced detection and prediction in advance in order to provide reliable technical support for the excavation.Based on the electromagnetic induction theory,we analyzed the characteristics of primary and secondary fields with a positive and negative wave form of current,proposed the fine processing of the advanced detection with variation rate of apparent resistivity and introduced in detail the computational formulae and procedures.The result of physical simulation experiments illustrate that the tectonic interface of modules can be judged by first-order rate of apparent resistivity with a boundary error of 5%,and the position of water body determined by the fine analysis method agrees well with the result of borehole drilling.This shows that in terms of distinguishing structure and aqueous anomalies,the first-order rate of apparent resistivity is more sensitive than the secondorder rate of apparent resistivity.However,some remaining problems are suggested for future solutions.展开更多
Load behavior is one of the most critical factors affecting mills' energy consumption and grinding efficiency, and is greatly affected by the liner profiles. Generally, as liner profiles vary, the ball mill performan...Load behavior is one of the most critical factors affecting mills' energy consumption and grinding efficiency, and is greatly affected by the liner profiles. Generally, as liner profiles vary, the ball mill performances are extremely different. In order to study the performance of the ball mill with regular polygon angle-spiral liners(RPASLs), experimental and numerical studies on three types of RPASLs, including regular quadrilateral, pentagonal and hexagonal, are carried out. For the fine product of desired size, two critical parameters are analyzed: the energy input to the mill per unit mass of the fine product, E*, and the rate of production of the fine product, F*. Results show that the optimal structure of RPASLs is Quadrilateral ASL with an assembled angle of 50°. Under this condition, the specific energy consumption E* has the minimum value of 303 J per fine product and the production rate F* has the maximum value of 0.323. The production rate F* in the experimental result is consistent with the specific collision energy intensity to total collision energy intensity ratio Es/Et in the simulation. The relations between the production rate F* and the specific energy consumption E* with collision energy intensity Es and Et are obtained. The simulation result reveals the essential reason for the experimental phenomenon and correlates the mill performance parameter to the collision energy between balls, which could guide the practical application for Quadrilateral ASL.展开更多
Laboratory experiments are frequently criticised,in part because of the sensitivity of the results to specific features of the design.This paper addresses an important question regarding the key aspect of the experime...Laboratory experiments are frequently criticised,in part because of the sensitivity of the results to specific features of the design.This paper addresses an important question regarding the key aspect of the experimental environment:How should the dependent variable–participants’choices–be operationalised?For the specific context of laboratory research on income tax compliance,we compare the effects of the two most common operationalisation types:the declaration of gross income versus the declaration of tax payment.It is found that compliance is higher when participants indicate their tax payment than when they declare their income.It is also discovered that the effects of the three policy parameters of the economic model(the tax rate,audit probability and fine rate)are stronger when participants declare their taxes than when they declare their income.These results are relevant for interpreting prior and future experimental evidence on tax compliance and can explain some contradictory previous findings.More broadly,this study suggests that the results of laboratory experiments may depend on specific features of the experimental design,which proposes a strong need for more systematic methodological research.展开更多
文摘Ⅰ. Exchange Rates Excharge rates are the rates at which currency conversion takes place. They themselves tell us nothing about the relative strength of the currencies involved or economics behind them, It simply reflects the difference between the denominations into which the two countries have chosen to divide their respective currencies. A currency is considered externally weak if the government is having difficulty maintaining the predetermined exchange rates under
基金Funded by the National Science Foundation of China(No.51574055)the Key State Laboratory of Coastal and Offshore Engineering(No.LP1720)
文摘To obtain the influence laws of the fine gangue rate on the properties of coal gangue cementitious paste, the slump, divergence, stratification, bleeding, setting time and mechanical strength with the change of fine gangue rate were studied on the basis of keeping the amount of cementing material and slurry concentration unchanged. The porosity and the distribution of pore diameter of the filling specimen for curing 28 d were tested by a mercury injection instrument under different fine gangue rate conditions. It was shown that the slump, divergence, setting time and compressive strength of the paste firstly increased and then decreased with increasing fine gangue rate. The stratification and bleeding rate decreased with increasing fine gangue rate. The smaller the critical pore size of the paste was, the smaller the porosity was, the smaller the average pore size was. When the fine gangue rate was 40%, the maximum critical pore diameter of the paste was 55.79 μm, and the corresponding porosity was 17.54%, and the properties of filling paste were the best. When the fine gangue rate further increased, the aggregate surface area increased, and the reaction product of cementitious materials could not effectively fill the pores. It weakened the agglomeration effect. The particles surface of coal gangue was fragmental and flake deposit with irregular shape and uneven fold morphology. It was easy to be bonded with the surface of other filling material. The hydration products of coal gangue cementitious material were a large number of C-S-H gel with fibrous shape and ettringite(AFt) with compact block structure. The theoretical reference was provided for the preparation of low cost gangue cemented filling materials in coal mines.
基金supports for this work,provided by the Natural Science Foundation of Jiangsu Province (No. BK2009095)the National Natural Science Foundation of China (No. 51004102)+1 种基金the National Science & Technology Support Project of the 11th Five-Year Plan of China (No. 2007Bak24B03)the State Basic Research and Development Program of China (No. 2007CB209400)
文摘Fault fracture zones and water-bearing bodies in front of the driving head are the main disasters in mine laneways,thus it is important to perform their advanced detection and prediction in advance in order to provide reliable technical support for the excavation.Based on the electromagnetic induction theory,we analyzed the characteristics of primary and secondary fields with a positive and negative wave form of current,proposed the fine processing of the advanced detection with variation rate of apparent resistivity and introduced in detail the computational formulae and procedures.The result of physical simulation experiments illustrate that the tectonic interface of modules can be judged by first-order rate of apparent resistivity with a boundary error of 5%,and the position of water body determined by the fine analysis method agrees well with the result of borehole drilling.This shows that in terms of distinguishing structure and aqueous anomalies,the first-order rate of apparent resistivity is more sensitive than the secondorder rate of apparent resistivity.However,some remaining problems are suggested for future solutions.
基金Supported by National Natural Science Foundation of China(Grant Nos.51675484,51275474,51505424)Zhejiang Provincial Natural Science Foundation of China(Grant Nos.LZ12E05002,LY15E050019)
文摘Load behavior is one of the most critical factors affecting mills' energy consumption and grinding efficiency, and is greatly affected by the liner profiles. Generally, as liner profiles vary, the ball mill performances are extremely different. In order to study the performance of the ball mill with regular polygon angle-spiral liners(RPASLs), experimental and numerical studies on three types of RPASLs, including regular quadrilateral, pentagonal and hexagonal, are carried out. For the fine product of desired size, two critical parameters are analyzed: the energy input to the mill per unit mass of the fine product, E*, and the rate of production of the fine product, F*. Results show that the optimal structure of RPASLs is Quadrilateral ASL with an assembled angle of 50°. Under this condition, the specific energy consumption E* has the minimum value of 303 J per fine product and the production rate F* has the maximum value of 0.323. The production rate F* in the experimental result is consistent with the specific collision energy intensity to total collision energy intensity ratio Es/Et in the simulation. The relations between the production rate F* and the specific energy consumption E* with collision energy intensity Es and Et are obtained. The simulation result reveals the essential reason for the experimental phenomenon and correlates the mill performance parameter to the collision energy between balls, which could guide the practical application for Quadrilateral ASL.
文摘Laboratory experiments are frequently criticised,in part because of the sensitivity of the results to specific features of the design.This paper addresses an important question regarding the key aspect of the experimental environment:How should the dependent variable–participants’choices–be operationalised?For the specific context of laboratory research on income tax compliance,we compare the effects of the two most common operationalisation types:the declaration of gross income versus the declaration of tax payment.It is found that compliance is higher when participants indicate their tax payment than when they declare their income.It is also discovered that the effects of the three policy parameters of the economic model(the tax rate,audit probability and fine rate)are stronger when participants declare their taxes than when they declare their income.These results are relevant for interpreting prior and future experimental evidence on tax compliance and can explain some contradictory previous findings.More broadly,this study suggests that the results of laboratory experiments may depend on specific features of the experimental design,which proposes a strong need for more systematic methodological research.