对于传递函数为G=1/(s*s+2*&*s+1)归一化二阶系统，制作一个能绘制该系统单位阶跃响应的图形用户界面。本例演示：（A）图形界面的大致生成过程；（B）静态文本和编辑框的生成；（C）坐标方格控制键的形成；（D）如何使用该界面。-for the transfer function of G = 1/(s* s* 2
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.001698s ]
SELECT `a`.`aid`,`a`.`title`,`a`.`create_time`,`m`.`username` FROM `jrk_downrecords` `a` INNER JOIN `jrk_member` `m` ON `a`.`uid`=`m`.`id` WHERE `a`.`status` = 1 GROUP BY `a`.`aid` ORDER BY `a`.`create_time` DESC LIMIT 10 [ RunTime:0.098281s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.001614s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.001766s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.001349s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.004275s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.001131s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.005058s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.017393s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001279s ]
UPDATE `jrk_articles` SET `hits` = 2 WHERE `id` = 4093 [ RunTime:0.023982s ]
