广播电视缝隙天线防水处理

缝隙天线具有增益高、性能稳定、定向效果好、架设方便、占用发射塔空间少、馈电点少、便于维护等优点.被广播电视部门广泛采用.该天线是把所有匹配、阻抗变换原件均封闭在一个玻璃钢罩内,采用全封闭型式,天线外面只有一个与主馈连接的输入接口(输入法兰),天线为立式安装,     

接头盒的种类

此类支架型接头盒包括所有放在支架上的接头盒。支架接头盒的技术要求低于地下接头盒。它必须符合抗御3m深水浸的标准，因为这些接头盒的高度与地平线同高，而且支架也并不一定具有防水功能。Bellcore GR-771标准允许支架式接头盒透气或密封。因此，GR-771支架式接头盒额定指标显然不能满足防洪要求。由于这些接头盒是靠支架保护的，故对防撞击、防压和防腐蚀的要求不高。Bellcore不要求对支架型接头盒做防冻、解冻试验。     

铝管电缆防水F头制作不良故障3例

高安市广播电视局在乡镇光缆联网中,主、支干电缆网络全部选用江苏山湖牌-12、-9无缝铝管电缆,F头全部选用防水免掏空型接头,但在施工中因F头制作粗糙,造成隐患,现对有关故障现象进行分析.     

卡西欧G＇zOne TYPE-R

酷似名表G-SHOCK的卡西欧G‘zOne系列手机在历时四年之后终于又推出最新款TYPE-R?A。和过去的G‘zOne系列一样．新产品属样具备超强的防水性能，其防水性能达到了JIS7级标准，这意味着该机能够在1米深的水中浸泡三十分钟而不会进水或变形，同时，为了获得更好的防震性能．卡西欧还对该产品进行了特别的加固设计。     

Modeling the interaction of solitary waves and semi-circular breakwaters by using unsteady reynolds equations

A vertical 2 -D numerical wave model was developed based on unsteady Reynolds equations. In this model, the k-epsilon models were used to close the Reynolds equations, and volume of fluid( VOF) method was used to reconstruct the free surface. The model was verified by experimental data. Then the model was used to simulate solitary wave interaction with submerged, alternative submerged and emerged semi-circular breakwaters. The process of velocity field, pressure field and the wave surface near the breakwaters was obtained. It is found that when the semi-circular breakwater is submerged, a large vortex will be generated at the bottom of the lee side wall of the breakwater ; when the still water depth is equal to the radius of the semi-circular breakwater, a pair of large vortices will be generated near the shoreward wall of the semi-circular breakwater due to wave impacting, but the velocity near the bottom of the lee side wall of the breakwater is always relatively small. When the semi-circular breakwater is emerged, and solitary wave cannot overtop it, the solitary wave surface will run up and down secondarily during reflecting from the breakwater. It can be further used to estate the diffusing and transportation of the contamination and transportation of suspended sediment.     

微型密封防水连接器

Mizu—P25微型防水连接器具有节省空间的2．50mm（O．098英寸）间距,是市场上首个和同尺寸的IP67标准密封线对线连接器系统,有助于确保最高等级的防护。MiZu-P25连接器备有最高达125V额定电压的低压型款和最高达250V额定电压的高压型款。     

美国科学家研制出防水耐用的陶瓷材料

正美国麻省理工学院的一个研究小组用稀土金属制成一种陶瓷材料,这种材料通常是具有亲水性的,也就是说它能够吸引水,是一种带有防水的电子结构陶瓷材料。许多防水或者亲水性材料都能够提升工业生产过程,例如:在海水淡化过程中进行水缩合反应,以及在发电厂中使用;但是这些材料很容易被磨损,尤其是在高温环境下。麻省理工学院的科研小组试图将陶瓷材料的耐磨性和非耐磨材料的亲水性相结合。他们采用稀土