钱塘一望浪波连 顷刻狂澜横眼前 闽海蓬莱第一山 秀出天涯几万寻——2015年7月新邮介绍

7月1日《钱塘江大潮》钱塘江大潮简称钱江潮,又称海宁潮,指发生在浙江省钱塘江流域,由于月球和太阳的引潮力作用,使海洋水面发生周期性涨落的潮汐现象。钱塘江大潮是世界一大自然奇观,这与钱塘江入海的杭州湾形状,以及它特殊的地形有关。杭州湾呈喇叭形,口大肚小。钱塘江河道自澉浦以西，急剧变窄抬高，致使河床的容量突然缩小，大量潮水拥挤进入狭浅的河道，潮头受到阻碍，后面的潮水又急速推进，迫使潮头陡芷，发生破碎，发出轰鸣，出现惊险而壮观的场面。

Prospects of Rowing Screws with Long Wavy Surface Blades

This paper devotes to rational design for the ship propellers with long wavy blades. Thin long blades create big elastic deformations, which can be a regulator of an optimum angle for attack. The wavy form provides stability on operational modes. To ensure stabilization to decrease in bending and torsion fluctuations, the main sectorial coordinates were defined by combining the shift centre with the gravity centre for computer geometrical models of the rowing screw blade and an idealized elastic deformable boundary liquid flow layer while unit thickness was offered. More rational petal forms of the long blade with a wavy surface are explained for exception of not free torsion.

气象:风景的化妆师

气象无处不在,在景观审美中,气象被誉为＂风景的化妆师＂,与旅游有着千丝万缕的关系。我们经常说＂看天出行＂,好天气是出行的必备条件,然而,有时我们也会专门为了某一气象景观而出门探寻。气象旅游资源有很多,雨景、云雾景、冰雪景、幻景、极光景等都是我们所熟知的气象景观。吉林雾凇、黄山云海、泰山日出和钱塘潮涌被誉为中国四大气象奇观,每年都会吸引无数游客前来。