The paper firstly analyzes the influence factor on material removal rate of curved optical work-pieces in the bonnet polishing. Then the experiments are conducted to reveal the effects of several polishing parameters ...The paper firstly analyzes the influence factor on material removal rate of curved optical work-pieces in the bonnet polishing. Then the experiments are conducted to reveal the effects of several polishing parameters on the material removal rate when the spherical optical glasses are polished with different curvature radius, such as the decrement of the bonnet, the rotational speed of the bonnet and the curvature radius of the work-piece＇s surface using a bonnet trial-manufacturing machine developed by our assignment groups. In the end, the curvilinear relationships between these parameters and the material removal rate are acquired and the laws of the effects on material removal rate in bonnet polishing by several parameters are given. When the spherical-pieces are polished with smaller curvature radius, it is not proportional to either bonnet decrement or bonnet rotational speed as described by the Preston equation although the removal rate increases as the relative velocity or the applied pressure increases. Therefore, for the purpose of calculating more accurately the material removal of the spherical work-pieces, the Preston equation should be modified and studied further.展开更多
THE great Chinese master-piece A Dream of Red Man-sions is also called The storyof the Stone.Author Cao Xueqin,whodevoted his life to writing it,mighthave been astonished to find thatin、the late 20th century someonew...THE great Chinese master-piece A Dream of Red Man-sions is also called The storyof the Stone.Author Cao Xueqin,whodevoted his life to writing it,mighthave been astonished to find thatin、the late 20th century someonewould take the second title of hisnovel quite iterally and carve itsentire contents on stone.The books transcribed on 280 colorful peb-bies and pieces of polished rock,fitting into a surface space of lessthan one square meter-an amaz-iug feat,considering the fact展开更多
The Song of Solomon is a series of love poems which contain 6 pieces of love poems and most part in the form of songs addressed by a man to a woman, and by the woman to the man, in order to express the love between th...The Song of Solomon is a series of love poems which contain 6 pieces of love poems and most part in the form of songs addressed by a man to a woman, and by the woman to the man, in order to express the love between them.Figures of speech are ways of making our language figurative. They can be divided into three parts, they are syntactical, semantic and phonetic rhetorical devices. These rhetorical devices can help us to heighten effect and to make the writing figuratively and vividly.These figures of speech used in the Song of Solomon make great contribution to the success description of these long songs.This essay will center on the figures of speech in the Song of Solomon.展开更多
American presidents get millions of letters every year.So far,more people are writing to President Clinton than wrote to anyother president.In five months of the Clinton administration,theWhite House received more tha...American presidents get millions of letters every year.So far,more people are writing to President Clinton than wrote to anyother president.In five months of the Clinton administration,theWhite House received more than three million pieces of mail.Thatis more than President Bush received the whole of 1992.展开更多
work on sth.与work at sth.的含义是不同的。一、work on sth.的意思主要有: 1.从事(某工作),致力于(做某事) 1)Green is working on(busy writing)a new novel. 2)He took out a piece of chalk and wrote his problem on theblackboa...work on sth.与work at sth.的含义是不同的。一、work on sth.的意思主要有: 1.从事(某工作),致力于(做某事) 1)Green is working on(busy writing)a new novel. 2)He took out a piece of chalk and wrote his problem on theblackboard.Then started to work on it.展开更多
基金Foundation of Harbin Institute of Technology,China(No.HIT.2001.10)Harbin Municipal Youth Foundation of China(No.2002AFQXJ040).
文摘The paper firstly analyzes the influence factor on material removal rate of curved optical work-pieces in the bonnet polishing. Then the experiments are conducted to reveal the effects of several polishing parameters on the material removal rate when the spherical optical glasses are polished with different curvature radius, such as the decrement of the bonnet, the rotational speed of the bonnet and the curvature radius of the work-piece＇s surface using a bonnet trial-manufacturing machine developed by our assignment groups. In the end, the curvilinear relationships between these parameters and the material removal rate are acquired and the laws of the effects on material removal rate in bonnet polishing by several parameters are given. When the spherical-pieces are polished with smaller curvature radius, it is not proportional to either bonnet decrement or bonnet rotational speed as described by the Preston equation although the removal rate increases as the relative velocity or the applied pressure increases. Therefore, for the purpose of calculating more accurately the material removal of the spherical work-pieces, the Preston equation should be modified and studied further.
文摘THE great Chinese master-piece A Dream of Red Man-sions is also called The storyof the Stone.Author Cao Xueqin,whodevoted his life to writing it,mighthave been astonished to find thatin、the late 20th century someonewould take the second title of hisnovel quite iterally and carve itsentire contents on stone.The books transcribed on 280 colorful peb-bies and pieces of polished rock,fitting into a surface space of lessthan one square meter-an amaz-iug feat,considering the fact
文摘The Song of Solomon is a series of love poems which contain 6 pieces of love poems and most part in the form of songs addressed by a man to a woman, and by the woman to the man, in order to express the love between them.Figures of speech are ways of making our language figurative. They can be divided into three parts, they are syntactical, semantic and phonetic rhetorical devices. These rhetorical devices can help us to heighten effect and to make the writing figuratively and vividly.These figures of speech used in the Song of Solomon make great contribution to the success description of these long songs.This essay will center on the figures of speech in the Song of Solomon.
文摘American presidents get millions of letters every year.So far,more people are writing to President Clinton than wrote to anyother president.In five months of the Clinton administration,theWhite House received more than three million pieces of mail.Thatis more than President Bush received the whole of 1992.
文摘work on sth.与work at sth.的含义是不同的。一、work on sth.的意思主要有: 1.从事(某工作),致力于(做某事) 1)Green is working on(busy writing)a new novel. 2)He took out a piece of chalk and wrote his problem on theblackboard.Then started to work on it.
