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With Airbus’s giant A380 airliner about to take to the skies, you might think planes could not get much bigger and you would be right. For a given design, it turns (1) , there comes a point where the wings become too heavy to generate (2) lift to carry their own weight. (3) a new way of designing and making materials could (4) that problem. Two engineers (5) University College London have devised an innovative way to customise and control the (6) of a material throughout its three dimension al structure.In the (7) of a wing, this would make possible a material that is dense, strong and load-bearing at one end, close to the fuselage, (8) the extremities could be made less dense, lighter and more (9) . It is like making bespoke materials, (10) you can customise the physical properties of every cubic millimetre of a structure.The new technique combines existing technologies in a(n) (11) way. It starts by using finite-element-analysis software, of the type commonly used by engineers, (12) a virtual prototype of the object. The software models the stresses and strains that the object will need to (13) throughout its structure. Using this information it is then (14) to calculate the precise forces acting on millions of smaller subsections of the structure. (15) of these subsections is (16) treated as a separate object with its own set of forces acting on it--and each subsection (17) for a different microstructure to absorb those local forces.Designing so many microstructures manually (18) be a huge task, so the researchers apply an optimisation program, called a genetic algorithm, (19) . This uses a process of randomisation and trial-and-error to search the vast number of possible microstructures to find the most (20) design for each subsection. 11（）
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吸宫术后闭经伴周期性下腹痛
高血压、水肿、蛋白尿
Text 2If you are what you eat, then you are also what you buy to eat. And mostly what people buy is scrawled onto a grocery list, those ethereal scraps of paper that record the shorthand of where we shop and how we feed ourselves. Most grocery lists end up in the garbage. But if you live in St. Louis, they might have a half-life you never imagined: as a cultural document, posted on the Internet.For the past decade, Biil Keaggy, 33, the features photo editor at The St. Louis Post-Dispatch, has been collecting grocery lists and since 1999 has been posting them online at www. Grocery lists, org. The collection, which now numbers more than 500 lists, is strangely addictive. The lists elicit two-fold curiosity--about the kind of meal the person was planning and the kind of person who would make such a meal. What was the shopper with vodka, lighters, milk and ice cream on his list planning to do with them In what order would they be consumed Was it a he or a she Who had written "Tootie food, kitten chow, bird food stick, toaster scrambles, coffee drinks" Some shoppers organize their lists by aisle; others start with dairy, go to cleaning supplies and then back to dairy before veering off to Home Depot. A few meticulous ones note the price of every item. One shopper had written in large letters on an envelope, simply, "Milk".The thin lines of ink and pencil jutting and looping across crinkled and torn pieces of paper have a purely graphic beauty. One of life’s most banal duties, viewed through the curatorial lens, can somehow seem pregnant with possibility. It can even appear poetic, as in the list that reads "meat, cigs, buns, treats".One thing Keaggy discovered is that Dan Quayle is not alone--few people can spell bananas and bagels, let alone potato. One list calls for "suchi" and "strimp". "Some people pass judgment on the things they buy," Keaggy says. At the end of one list, the shopper wrote "Bud Light" and then "good beer". Another scribbled "good loaf of white bread". Some pass judgment on themselves, like the shopper who wrote "read, stay home or go somewhere, I act like my mom, go to Kentucky, underwear, lemon". People send messages to one another, too. Buried in one list is this statement: "If you buy more rice, I’ll punch you." And plenty of shoppers, like the one with both ice cream and diet pills on the list, reveal their vices. Through studying grocery lists, Bill Keaggy finds that（）
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