第二篇

Pushbike Peril Low speed bicycle crashes can badly injure—or even kill—children if they fall onto the ends of the handlebars (车把). So a team of engineers is redesigning the humble handlebar in a bid to make it safer. Kristy Arbogast, a bioengineer at the Children’s Hospital of Philadelphia in Pennsylvania, began the project with her colleagues after a study of serious abdominal (腹部的) injuries in children in the past 30 years showed that more than a third were ca,used by bicycle accidents. "The task was to identify how the injuries occurred and come up with some countermeasures (对策)", she says. By interviewing the Children and their parents, Arbogast and her team were able to reconstruct (重建;重构) many of the accidents and identified a common mechanism responsible for serious injures. They discovered that most occur when children hit an obstacle at a slow speed, causing them to topple over. To maintain their balance they turn the handlebars, through 90 degrees — but their momentum (冲力) forces them into the end of the handlebars. The bike then falls over and the other end of the handlebars hits the ground, ramming it into their abdomen. The solution the group came up with is a handgrip(握柄) fitted with a spring and damping (制动的;减速的,缓冲的) system. The spring absorbs up to 50 percent of the forces transmitted through the handlebars in an impact. The group hopes to commercialize (使商品化) the device, which should add only a few dollars to the cost of a bike. "But our task has been one of education because up until now, bicycle manufacturer were unaware of the problem," says Arbogast. The team has also approached the US Consumer Product Safety Commission to try to persuade man-ufacturers to adopt the new design. A decision is expected later this year.

In which of the following ways the new handgrip works