To compare the level of friction resistance (fr) of different design self-ligating brackets using various bracket-wire combination in dry state during orthodontic phase of leveling and aligning.

探讨在干燥条件下，在牙齿排齐整平阶段应用不同的自锁托槽与不同的镍钛圆丝组合所产生的滑动阻力。

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Using the wrong combination will result in a bad connection between crankset and bottom bracket and may lead to a damaged serration of your crankset.

如果硬要这样配合使用，牙盘和中轴之间结合的会很糟糕，可能会导致牙盘的花键损坏。

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The combination of a larger AMT exemption and higher thresholds for the exemption phaseout and top AMT tax bracket will further reduce the number of taxpayers owing AMT to just 3.4 million in 2013.

FORBES: How the New Tax Act Affects the Alternative Minimum Tax