For the 32 mentally ill, seriously delinquent adolescents who live there, the August Aichhorn Center on West 106th Street is the end of the line. "We get the youngsters nobody else can handle," says the center's director, Dr. Michael Pawel, 53, who also designed and built the facility. They've exhibited every kind of bad behavior (armed robbery, arson, sexual assault, animal torture), and most have already been bounced from foster homes, group homes, state hospitals, or juvenile-detention centers. Here, though, acting out won't get you thrown out. "Pawel's commitment to young people is outstanding," says Susan Thaler, the local field coordinator for the State Office of Mental Health. "He's really giving them a second chance." Pawel, a psychiatrist whose patients think he's crazy for pedaling his mountain bike between the center and his private practice on West 72nd Street every day, first thought of Aichhorn more than twenty years ago, when hard-to-handle adolescents would get passed back and forth between the juvenile-justice and mental-health systems. "No agency wanted them," he says, but he was convinced that the lack of stability increased the likelihood of a troubled teen's becoming a lifelong sociopath. One day, he was kvetching to the staff at Spofford Juvenile Center about the system's inadequacy when someone said to him, "Well, why don't you start something? You're a doctor." The first of its kind, the Aichhorn Center is part hospital, part jail. Yet it's cheaper than either (the program costs roughly $250 per day, vs. $750 a day at a state psychiatric hospital) and feels more like a college dorm than like a locked-down psych ward. Pawel's success is apparent in the utter normalcy of the kids' rooms, decorated with the covers of hip-hop magazines and movie posters, and the relaxed posture of the erstwhile menaces as they do their homework together in the hallways. "The basic message," says Pawel, "is that they can stay here until there is a better place for them to go."