Mr. Zhang, I share below what I observed during the past one year:
1. At 2010-November
Fed is about to start QE2, but the decision was made back to 2010-August. Such well-informed action (a big buyer will buy later) allow market participant to use such good news and buy upfront, so price at top (yield at lowest) when Fed start to buy.
2. Current situation
Now Fed announced to use received payment to re-invest after QE2, that is a bad news to treasury, like Bill Gross said a big buyer will go away. But at the same time in 2011-May, US reached its debt ceiling, which make the issuance less than normal. As investor keep a certain amount of money into treasury (they might increase weight in light of nowaday slowing economy and the fact that investor have avoided treasury due to Fed dominance in the market from 2010-November to 2011-June), so when demand is same (or more) and supply is lesson, treasury raise in 2011-May!
3. Outlook
US politician is negotiating on budget and raising debt ceiling is on hold. They set a time to get it done by early 2011-July. At the same time, treasury return to a free market without Fed dominance, so likely 10-year treasury yield remain above 3% in 2011-second-half. One exception is when economy data is getting worse into likely a double-dip, when the yield will fall below 3%.
(My apologize to use English this time, which I type faster and can explain my thinking better. I assumed English is ok in your blog, but I certainly will adhere to Chinese if it is a preferred one.)
DPZ Blog 
Mr. Zhang, I share below what I observed during the past one year:
1. At 2010-November
Fed is about to start QE2, but the decision was made back to 2010-August. Such well-informed action (a big buyer will buy later) allow market participant to use such good news and buy upfront, so price at top (yield at lowest) when Fed start to buy.
2. Current situation
Now Fed announced to use received payment to re-invest after QE2, that is a bad news to treasury, like Bill Gross said a big buyer will go away. But at the same time in 2011-May, US reached its debt ceiling, which make the issuance less than normal. As investor keep a certain amount of money into treasury (they might increase weight in light of nowaday slowing economy and the fact that investor have avoided treasury due to Fed dominance in the market from 2010-November to 2011-June), so when demand is same (or more) and supply is lesson, treasury raise in 2011-May!
3. Outlook
US politician is negotiating on budget and raising debt ceiling is on hold. They set a time to get it done by early 2011-July. At the same time, treasury return to a free market without Fed dominance, so likely 10-year treasury yield remain above 3% in 2011-second-half. One exception is when economy data is getting worse into likely a double-dip, when the yield will fall below 3%.
(My apologize to use English this time, which I type faster and can explain my thinking better. I assumed English is ok in your blog, but I certainly will adhere to Chinese if it is a preferred one.)