1、适用范围本标准对用于书写、制图及画图等之铅笔(以下称铅笔)及彩色铅笔(以下称彩色铅笔)作出规定(1).但不包括含有水彩用,复写用等染料的特殊彩色铅笔.注①本标准亦适用于铅笔和彩色铅笔组合的铅笔.备考1、本标准中的引用标准如附表...1、适用范围本标准对用于书写、制图及画图等之铅笔(以下称铅笔)及彩色铅笔(以下称彩色铅笔)作出规定(1).但不包括含有水彩用,复写用等染料的特殊彩色铅笔.注①本标准亦适用于铅笔和彩色铅笔组合的铅笔.备考1、本标准中的引用标准如附表1所示.2、本标准中与之对应的国际标准如下所示.ISO/DIS 8124-3.2 Safety oftoys--Part 3:Migration of certainelements.ISO 9177-2:1989 Mechanicalpencils--Part 2:Black leads--Classification and dimensions.ISO 9180:1988 Black leads for wood-cased pencils--Classification anddiameters.展开更多
In order to accurately predict the productivity of herringbone multilateral well,a new productivity prediction model was founded.And based on this model,orthogonal test and multiple factor variance analysis were appli...In order to accurately predict the productivity of herringbone multilateral well,a new productivity prediction model was founded.And based on this model,orthogonal test and multiple factor variance analysis were applied to study optimization design of herringbone multilateral well.According to the characteristics of herringbone multilateral well,by using pressure superposition and mirror image reflection theory,the coupled model of herringbone multilateral well was developed on the basis of a three-dimensional pseudo-pressure distribution model for horizontal wells.The model was formulated in consideration of friction loss,acceleration loss of the wellbore and mixed loss at the confluence of main wellbore and branched one.After mathematical simulation on productivity of the herringbone multilateral well with the coupled model,the effects of well configuration on productivity were analyzed.The results show that lateral number is the most important factor,length of main wellbore and length of branched wellbore are the secondary ones,angle between main and branched one has the least influence.展开更多
A quasi-geostrophic barotropic vorticity equation model is used to simulate the influences of topographic forcing and land friction on landfall tropical cyclone track and intensity. The simulation results show that tr...A quasi-geostrophic barotropic vorticity equation model is used to simulate the influences of topographic forcing and land friction on landfall tropical cyclone track and intensity. The simulation results show that tropical cyclone track may have sudden deflection when the action of topographic friction dissipation is considered, and sudden deflection of the track is easy to happen and sudden change of tropical cyclone intensity is not clear when the intensity of tropical cyclone is weak and the land friction is strong. The land friction may be an important factor that causes sudden deflection of tropical cyclone track around landfall.展开更多
文摘1、适用范围本标准对用于书写、制图及画图等之铅笔(以下称铅笔)及彩色铅笔(以下称彩色铅笔)作出规定(1).但不包括含有水彩用,复写用等染料的特殊彩色铅笔.注①本标准亦适用于铅笔和彩色铅笔组合的铅笔.备考1、本标准中的引用标准如附表1所示.2、本标准中与之对应的国际标准如下所示.ISO/DIS 8124-3.2 Safety oftoys--Part 3:Migration of certainelements.ISO 9177-2:1989 Mechanicalpencils--Part 2:Black leads--Classification and dimensions.ISO 9180:1988 Black leads for wood-cased pencils--Classification anddiameters.
基金Project(12521044) supported by Scientific and Technological Research Program of Heilongjiang Provincial Education Department,China
文摘In order to accurately predict the productivity of herringbone multilateral well,a new productivity prediction model was founded.And based on this model,orthogonal test and multiple factor variance analysis were applied to study optimization design of herringbone multilateral well.According to the characteristics of herringbone multilateral well,by using pressure superposition and mirror image reflection theory,the coupled model of herringbone multilateral well was developed on the basis of a three-dimensional pseudo-pressure distribution model for horizontal wells.The model was formulated in consideration of friction loss,acceleration loss of the wellbore and mixed loss at the confluence of main wellbore and branched one.After mathematical simulation on productivity of the herringbone multilateral well with the coupled model,the effects of well configuration on productivity were analyzed.The results show that lateral number is the most important factor,length of main wellbore and length of branched wellbore are the secondary ones,angle between main and branched one has the least influence.
基金Model System for Monitoring the Interactions Between Air-Sea-Land in Coastal Area and Predicting Disaster-Causing Weather by China Meteorological Administration
文摘A quasi-geostrophic barotropic vorticity equation model is used to simulate the influences of topographic forcing and land friction on landfall tropical cyclone track and intensity. The simulation results show that tropical cyclone track may have sudden deflection when the action of topographic friction dissipation is considered, and sudden deflection of the track is easy to happen and sudden change of tropical cyclone intensity is not clear when the intensity of tropical cyclone is weak and the land friction is strong. The land friction may be an important factor that causes sudden deflection of tropical cyclone track around landfall.
