摘要:

So intriguedwas 18‐year‐old Natasha by the machines she helped conceive, design, and construct on the set of a kids' TV show slated to air this winter that she changed her college major in order to continue the work in school.

ISSN:0031-9228    

DOI:10.1063/1.2387082

出版商:AIP    

年代:1906

数据来源: AIP

摘要:

An apparent clashover the role of advisers on the NASA Advisory Council led to the dismissal of two members of the council's science committee and the resignation of a third in August, according to NAC chairman Harrison Schmitt and one of the affected scientists. The tension between NASA administrators and the scientists is centered on ongoing disputes at the space agency about the balance between the science and manned programs. Although NASA's overall R&D funding is likely to increase by more than 7&percent; in fiscal year 2007, virtually all of that increase is expected to go to developing new manned space vehicles. Science funding would stay flat, which follows sharp cuts that were made to the program last year.

ISSN:0031-9228    

DOI:10.1063/1.2387083

出版商:AIP    

年代:1906

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2387085

出版商:AIP    

年代:1906

数据来源: AIP

摘要:

Mechanics as a science of motion, as distinguished from a science of machines such as the lever and windlass, started early in the 17th century. By the middle of the next century it had become clear that Isaac Newton's three laws suffice for the motions of “point masses,” but it was not yet clear how–and indeed whether–those laws could be extended to handle the motions of fluids or rigid bodies. Thus the 18th century saw new laws such as the principle of least action proposed and disputed. The most celebrated of those disputes, concerning the conservation ofvis viva(Latin for “living force” and akin to what we now call kinetic energy), was already under way by 1686, the year before Newton published his laws of motion in thePrincipia.

ISSN:0031-9228    

DOI:10.1063/1.2387086

出版商:AIP    

年代:1906

数据来源: AIP

摘要:

Almost a billion years ago, Nature engineered an ingenious solution to the problem of converting chemical energy to mechanical energy in living things: the creation of a gradient in the concentration of protons across mitochondrial membranes. Human beings came up with a radically different solution just prior to the Industrial Revolution: the heat engine and its conversion of thermal energy from a chemical reaction into work. Steam engines, first patented in 1698, could provide vast amounts of power for locomotives and industrial processes. The trouble was that the steam engine's need for large amounts of water as a working fluid limited its practical use to large installations. It wasn't until Nikolaus Otto in 1861 and Rudolf Diesel in 1897 devised the two earliest variants of the internal combustion engine that engineers could circumvent the need to carry around tons of water. Engine sizes shrank in response, which kick‐started the motor‐vehicle industry with all its eventual consequences, including societies' dependence on fuel resources and the world's changing environment.

ISSN:0031-9228    

DOI:10.1063/1.2387087

出版商:AIP    

年代:1906

数据来源: AIP

摘要:

On 4 June 1924, a relatively unknown Satyendra Nath Bose from Dacca University in East Bengal, India, sent a short article to Albert Einstein with an accompanying letter (see figure 1), which beginsRespected Sir,I have ventured to send you the accompanying article for your perusal and opinion. I am anxious to know what you think of it. You will see that I have tried to deduce the coefficient8&pgr;&ngr;2/c3in Planck's law independent of the classical electrodynamics only assuming that the ultimate elementary regions in the Phase‐space has the contenth3.I do not know sufficient German to translate the paper. If you think the paper worth publication, I shall be grateful if you arrange its publication inZeitscrift fu¨r Physik.Bose goes on:Though a complete stranger to you, I do not feel any hesitation in making such a request. Because we are all your pupils though profiting only by your teachings through your writings….Yours faithfully,S. N. Bose

ISSN:0031-9228    

DOI:10.1063/1.2387088

出版商:AIP    

年代:1906

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2387089

出版商:AIP    

年代:1906

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2387091

出版商:AIP    

年代:1906

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2387092

出版商:AIP    

年代:1906

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2387093

出版商:AIP    

年代:1906

数据来源: AIP