比空气重的

Experimental conditions were: two equiponderant crucibles, 3~5mg equiponderant writing and blank paper, static air, heating rate 10℃/min, relative age between 2 days and 5 years.

特征峰出现的条件为：等重的字迹和空白纸分别置于2个等重的坩埚；以装有空白纸的坩埚作为参比；实验气氛为静态空气；升温速率10℃/min；字迹书写后存放时间为2~365×5d。

In the present work poly is prepared by chemical vapor deposition polymerization from [2.2] paracyclophane. Thermal gravimetrical analysis is used to study the thermal degradation. It is found that the onset of thermal degradation of poly in air is much lower than that in N2 due to the existence of O2 in the air.

用化学气相沉积聚合法制备了聚对亚苯基二亚甲基膜，由傅立叶变换红外光谱图证实了其化学结构采用热重分析研究了PPX的热降解性能，结果表明，在空气氛围中由于氧气的参与，其热稳定性比在N2中差，热氧化降解明显。

That day they became the first people to demonstrate sustained flight of a heavier-than-air machine under the complete control of the pilot.

他们在那天也率先成为完全掌控这架比空气还重的机器而持续飞行的人。

The first human-powered, heavier-than-air flight took place in North Carolina in 1903. The airplane was designed and built by the Wright brothers, after years of unsuccessful attempts.

世界第一架由人力发动、比空气还重的飞机，一九O三年在美国北卡罗莱纳州升空，莱特兄弟经过多年失败的尝试后，才设计打造了这架飞机。

To overcome the drawbacks in the weight and cost of the antenna with the corrugated soft surface, a new patch antenna with patch rings is designed. Its weight is about 1/4 less than the antenna with the corrugated soft surface and it is inexpensive. Good experimental results are obtained. The radiation pattern of the antenna is more rotationally symmetric, and a more reduction on the sidelobe levels of the antenna is achieved as compared to the antenna with the corrugated soft surface. In conclusion, in the present thesis both theoretical and experimental research works have been carried out intensively on patch antennas based on photonic-bandgap structures.

为了克服皱褶软表面天线份量重，加工费用贵等缺点，我们对空气介质的皱褶圆环结构软表面天线进行了改进，将周期分布的皱褶圆环平面化，并保持结构的软表面特性，设计出了一种新的平面圆环结构的软表面天线并进行了实验研究，加工的平面圆环结构天线比皱褶圆环结构天线重量减轻了约1/4，加工费用大大降低，所取得的实验结果显示，该平面圆环结构软表面天线的方向图的轴对称性得到了改善，在俯仰角从0°～-90°的范围内天线H面的波束与E面重合，与皱褶圆环结构相比，天线的旁瓣和背瓣受到了更大的抑制，E面方向图上+120°方向的旁瓣被明显削弱。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。