scientific american - 1998 04 - the unwired world
scientific american - 1998 04 - the unwired world
... and applied them to the time-honored tech- nology of fuel cells. The key was in the packaging. Whereas most fuel-cell re- searchers start with the design of the electrolyte and electrodes, Hockaday re- alized ... aperture, the su- perconducting magnet deflects the neg- atively charged electrons in one direc- tion and the positively charged protons and positrons in the other....
Ngày tải lên: 12/05/2014, 15:35
scientific american - 1994 04 - the dilemmas of prostate cancer
... powers can help them rise to the top. Since then, the Morrises and Alexan- der have had a falling-out, with each side accusing the other of hogging cred- it for the concept of nonlethality. ÒAlex- ander ... of the AC Þeld. When the marble is hopping down the egg tray with the help of the AC Þeld, augmenting the av- erage tilt of the egg tray by increasing the DC voltag...
Ngày tải lên: 12/05/2014, 14:54
scientific american - 1993 04 - controlling the quantum jitters of atoms
... SciDex™, SCI- ENTIFIC AMERICAN, 415 Madison Ave- nue, New York, N.Y. 1001 7-1 111, or fax (212) 35 5-0 408. Photocopying rights are hereby grant- ed by Scientific American, Inc., to li- braries and others ... stable, the high birth rates of the baby boom postponed the aging of the population by widen- ing the base of the age structure again. As the baby boomers grow olde...
Ngày tải lên: 12/05/2014, 14:49
scientific american - 1995 06 - the world's strongest magnets
... that they were the few Cretaceous survivors. The foundation of this theory began to shake in 1981, when fossils of Òop- posite birdsÓ were unearthed in China and, then, all over the Northern Hemi- sphere. ... and lead to the hy- poactivity seen there during clinical de- pression. If he is right, the theory would explain the gender gap, at least in part. Others at the NIMH have m...
Ngày tải lên: 12/05/2014, 15:01
scientific american - 1998 01 - flying over the solar system
... of a tiny needle. They also tested the glucose levels in these volunteers by the finger-stick method. They found that both the skin-fluid sample and the fin- ger-stick measured the correct glucose levels ... outside the cell and the other inside. The component outside the cell is the extracellu- lar matrix; the compressive “girders” inside the cell can be ei- ther micr...
Ngày tải lên: 12/05/2014, 15:33
scientific american - 1998 02 - wrapping up the universe
... the thigh was shorter than the shin, and the fibula, the bone to the side of the shinbone, was re- The Origin of Birds and Their Flight Scientific American February 1998 43 Bones of Contention A lthough ... bats, the hand part of the wing generates the thrust, and the rest of the wing provides the lift. Jeremy M. V. Rayner of the University of Bristol showed i...
Ngày tải lên: 12/05/2014, 15:33
scientific american - 1998 11 - greenland's mysterious meteor - fire over the ice
... one of those Tranquilli- ty-base-here -the- Eagle-has-landed, NASA-flight-control jubilation scenes. Laima is the Latvian goddess of good fortune, and the name was a homage to the heritage of Juris ... first time. The heat is daunting. As the after- noon wears on, the debate between Johnson and Fiedel moves first one way, then the other, like a tug-of-war. The debate might never...
Ngày tải lên: 12/05/2014, 15:48
scientific american - 2003 04 - 50 years of the double helix
... development,” the au- thors wrote in the winter-spring issue of Law and Con- temporary Problems. (Their other article on the Bayh- Dole Act appeared in the January-February issue of American Scientist.) Rai ... more of the craft’s mass to the all-important ther- mal shield. After descending to the lower at- mosphere, the capsule could float on para- chutes to an ocean landing...
Ngày tải lên: 12/05/2014, 16:16
scientific american - 2004 04 - has science missed half the brain
... the turn of the 20th century.” The stone “contains more lithium than any other stone on the planet” and “emits a signa- ture one-of-a-kind healing energy.” How does the Golden ‘C’ water get these ... subjects at the time of the serendipitous observation. Of the 30 individuals who received the EP-MRSI scans, 23 reported immediate mood im- provement, the team says in the J...
Ngày tải lên: 12/05/2014, 16:19
scientific american - 1993 01 - the turbulent birth of the milky way
... 4,400 12-BILLION-YEAR- OLD AGE TRACK 15-BILLION-YEAR- OLD AGE TRACK NGC 288 NGC 362 Copyright 1992 Scientific American, Inc. means that within the halo the only re- maining main-sequence stars are the extremely ... declines as the reefs get farther away from two centersÑone in the Indo-Pa- ciÞc and the other in the Caribbean. The outlines of a map marking plum- meting dive...
Ngày tải lên: 12/05/2014, 14:48