America President Obama’s Inauguration Streaming Live(video) from Hulu
January 19th, 2009If you can’t make the trip to Washington, D.C., or watch live TV for Tuesday’s presidential inauguration. You may choose watch the following online live stream from Hulu. It will start at noon at 10 a.m. EST(eastern time), on January 20th.
Structure and properties of polysiloxane-modified polyurethane
December 9th, 2008Polyurethane is a kind of polymer with urethane bond and(or) isocyanate group, which has good strength, hardenss and wear-resistance, etc., but it has also the shortage of inflammability and degeneration. Polysilioxane has excellent heat-resistance, durability and hydrophobic properties. Polysiloxane-polyurethane copolymer is a new kind of polymer material with the properties of polyurethane and polysiloxane, it is also one of the best candidates to be used to modify polyurethane. But the modifying reaction used to be realized in organsolvent and that would pollute the environment.
In view of the present state, by using peculiar synthesizing technical conditions, we synthesized three kinds of polysiloxane-modified polyurethane copolymers without organsolvent which were based on aminoethyl-aminopropyl polydimethylsiloxane and dihydroxy-terminated polydimethylsiloxaneand linearity amino polysiloxane with amino and hydroxyl.We also synthesized the polysiloxane-modified polyurethane/montmorillonite nanocomposites basing on the first polysiloxane-modified polyurethane.
The basic synthesizing technical conditions of the three kinds of polysiloxane-modified polyurethane had been studied. The effects of polysiloxane content, curing agent and polyether on mechanical properties , surface hydrophobic properties and heat-resistance of copolymer were investigated, and the polysiloxane content of polysiloxane-modified polyuretnane with the best synthetical properties
was determined. Besides, the microcosmic morphology of copolymer was investigated by SEM.
Firstly, the polysiloxane content and synthesizing technical conditions of polysiloxane-modified polyurethane/montmorillonite nanocomposites were determined. Secondly, the effects of montmorillonite additive on mechanical properties and surface hydrophobic properties of nanocomposites prepared by different polyethers were studied. Finally, the heat-resistance and microcosmic morphology of the exfolianted nanocomposite prepared by polyoxypropylene triol were investigated.
Randy Pausch Lecture: Time Management
August 3rd, 2008Randolph Frederick Pausch (October 23, 1960 – July 25, 2008) was an American professor of computer science, human-computer interaction and design at Carnegie Mellon University (CMU) in Pittsburgh, Pennsylvania, and a best-selling author who achieved worldwide fame for his “The Last Lecture” speech on September 18, 2007 at Carnegie Mellon.
In August 2006, Pausch was diagnosed with pancreatic cancer. He pursued a very aggressive cancer treatment that included Whipple procedure surgery and experimental chemotherapy; however, in August 2007 he was told the cancer had metastasized to his liver and spleen, which meant it was terminal. He then started palliative chemotherapy, intended to extend his life as long as possible. At that time, doctors estimated he would remain healthy for another three to six months. On May 2, 2008, a PET scan showed that his cancer had spread to his lungs and some lymph nodes in his chest, and that he had some metastases in his peritoneum and retroperitoneum.