ON THE RATE OF POINTWISE CONVERGENCE OF THE DURRMEYER-TYPE OPERATORS

For bounded or some locally bounded functions f measurable on an interval I there is estimated the rate of convergence of the Durrmeyer-type operators Lnf at those points x∈IntI at which the one-sided limits f(x± 0) exist. In the main theorems the Chanturiya's modulus of variation is used.

Process optimization of billet continuous caster and practice verification

This study analyzes the factors of influence on 0~# continuous caster in No.1 Steelmaking Plant of Xinjiang Bayi Iron & Steel Corporation(hereinafter referred to as Basteel).Diameter of tundish upper nozzle is small,and the molten steel leakage accidents have been greatly manifolded in the high casting speed.In order to increase yield of 0~# continuouse caster in No.1 Steelmaking Plant of Xinjiang Bayi Iron & Steel Corporation,and a series of amelioration measure was put forward.Through enlarging diameter of tundish upper nozzle(fromφ21 mm toφ21.5 mm ),after the water distribution of the secondary cooling was optimized.Based on stabilizing the quality,improving the average casting speed and work rate of the caster,the capacity of the billet continuous caster was improved.A better results was gained;the average casting speed had been increased from 3.04 m/min to 3.21 m/min.Production of the caster had been improved from 1 005 179.926 t in 2008 to 1 040 853.075 t in 2009.Quality of the concasting billets and production had also been stabilized.

Dephosphorization stability of hot metal by double slag operation in basic oxygen furnace

Double slag process was adopted to produce low-phosphorus steel from middle-phosphorus hot metal.To achieve a stable dephosphorization operation,conventional process was modified as follows：the blowing time was extended by approximately 1min by reducing the oxygen supply flow rate;calcium ferrite pellets were added to adjust the slag composition and viscosity;the dumping temperature was lowered by 30-50°C by the addition of calcium ferrite pellets during the double slag process to prevent phosphorus in the slag from returning to the molten steel;and the bottom-blown gas flow was increased during the blowing process.For 40 heats of comparative experiments,the rate of dephosphorization reached 91% and ranged between 87% and 95%;the phosphorus,sulfur,manganese,and oxygen contents calculated according to the compositions of molten steel and slag as well as the temperature of molten steel at the end-point of the basic oxygen furnace process were similar to the equilibrium values for the reaction between the slag and the steel.Less free calcium oxide and metallic iron were present in the final slag,and the surface of the slag mineral phase was smooth,clear,and well developed,which showed that the slag exhibited better melting effects than that produced using the conventional slag process.A steady phosphorus capacity in the slag and stable dephosphorization effects were achieved.

Applications of an IS-MP Model with Yield Curve

This paper interest rates （i.e., the recent macroeconomic presents an IS-MP model with the term structure of yield curve） and discusses some of its applications to activities and policy issues. Specifically, the model is employed to explain （1） why a steepening yield curve may signal the subsequent economic expansion, （2） why long-term zero interest rate policy （ZIRP） may not completely avoid recessions, but disables the yield curve from being inverted to signal the following economic recession, （3） how Operation Twist （OT） may help ease the recession, in particular, under ZIRP, and what limit it may face.