Serial reuse raceways in fish hatcheries typically use dam boards and screens to separate each raceway unit in the series. This paper describes a novel raceway splash plate constructed of aluminum plate and angle, whi...Serial reuse raceways in fish hatcheries typically use dam boards and screens to separate each raceway unit in the series. This paper describes a novel raceway splash plate constructed of aluminum plate and angle, which eliminates the need for screens when mounted on top of raceway dam boards. In addition to reducing the labor required to remove and replace, and clean screens, the splash plate increased the amount of available rearing space. Incoming water dissolved oxygen concentrations were also increased. These splash plates are relatively easy and inexpensive to fabricate, and their use can lead to increased efficiencies during hatchery rearing.展开更多
提出了一种Ka频段卫星通信地球站赋形天线的设计方法。该天线主面为环焦抛物面,采用溅射板式馈源。初级馈源、介质材料及副面通过胶粘接。文中理论推导了赋形等关键设计公式。根据设计结果进行天线样机加工,并进行了方向图测试。测试结...提出了一种Ka频段卫星通信地球站赋形天线的设计方法。该天线主面为环焦抛物面,采用溅射板式馈源。初级馈源、介质材料及副面通过胶粘接。文中理论推导了赋形等关键设计公式。根据设计结果进行天线样机加工,并进行了方向图测试。测试结果证明该1 m口径天线增益高达47 d Bi,且天线性能与理论仿真基本吻合,表明该设计方法有效可行。展开更多
研究并设计了一种工作在Ku波段的溅散板型抛物面天线.利用电磁仿真软件CST进行仿真设计,完成了天线结构参数的提取和电气性能的分析.并对样件进行实际测试与调试,测试和仿真计算结果基本一致,远场方向图完全满足ETSI Standard Range1 Cl...研究并设计了一种工作在Ku波段的溅散板型抛物面天线.利用电磁仿真软件CST进行仿真设计,完成了天线结构参数的提取和电气性能的分析.并对样件进行实际测试与调试,测试和仿真计算结果基本一致,远场方向图完全满足ETSI Standard Range1 Class2包络电气要求.与现有的溅散板馈源相比,具有开口辐射波导终端匹配性好、天线电压驻波比小(小于1.3∶1)、低风载负荷、低制造成本等优点;天线效率在60%以上,介质赋形简单,易于批量生产.展开更多
Structures separating fish hatchery ponds from open spring water sources must restrict fish movement from the pond to the spring, allow for constant water flow, and potentially reduce incoming spring water gas supersa...Structures separating fish hatchery ponds from open spring water sources must restrict fish movement from the pond to the spring, allow for constant water flow, and potentially reduce incoming spring water gas supersaturation. This article describes a novel inlet structure that fulfills those requirements. In addition, it requires minimal maintenance, and allows for the quick and easy removal of debris in the event of partial plugging. This simple aluminum structure consists of a mount for attachment to the inflow pipe and a terminal splash plate with aeration holes. The splash plate is perpendicular to the water flow during normal operations to both prevent fish from jumping into the pipe and aerate the incoming water. However, it can be easily swiveled upward for the efficient removal of debris. Use of the inlet structure consistently decreased gas supersaturation in the spring water as it entered the fish production pond. By decreasing gas levels and maintaining water flows, potentially hazardous fish health issues can be avoided by using this structure. In addition, this relatively inexpensive and simple device will greatly reduce the labor required for removing debris compared to traditional screens.展开更多
文摘Serial reuse raceways in fish hatcheries typically use dam boards and screens to separate each raceway unit in the series. This paper describes a novel raceway splash plate constructed of aluminum plate and angle, which eliminates the need for screens when mounted on top of raceway dam boards. In addition to reducing the labor required to remove and replace, and clean screens, the splash plate increased the amount of available rearing space. Incoming water dissolved oxygen concentrations were also increased. These splash plates are relatively easy and inexpensive to fabricate, and their use can lead to increased efficiencies during hatchery rearing.
文摘提出了一种Ka频段卫星通信地球站赋形天线的设计方法。该天线主面为环焦抛物面,采用溅射板式馈源。初级馈源、介质材料及副面通过胶粘接。文中理论推导了赋形等关键设计公式。根据设计结果进行天线样机加工,并进行了方向图测试。测试结果证明该1 m口径天线增益高达47 d Bi,且天线性能与理论仿真基本吻合,表明该设计方法有效可行。
文摘研究并设计了一种工作在Ku波段的溅散板型抛物面天线.利用电磁仿真软件CST进行仿真设计,完成了天线结构参数的提取和电气性能的分析.并对样件进行实际测试与调试,测试和仿真计算结果基本一致,远场方向图完全满足ETSI Standard Range1 Class2包络电气要求.与现有的溅散板馈源相比,具有开口辐射波导终端匹配性好、天线电压驻波比小(小于1.3∶1)、低风载负荷、低制造成本等优点;天线效率在60%以上,介质赋形简单,易于批量生产.
文摘Structures separating fish hatchery ponds from open spring water sources must restrict fish movement from the pond to the spring, allow for constant water flow, and potentially reduce incoming spring water gas supersaturation. This article describes a novel inlet structure that fulfills those requirements. In addition, it requires minimal maintenance, and allows for the quick and easy removal of debris in the event of partial plugging. This simple aluminum structure consists of a mount for attachment to the inflow pipe and a terminal splash plate with aeration holes. The splash plate is perpendicular to the water flow during normal operations to both prevent fish from jumping into the pipe and aerate the incoming water. However, it can be easily swiveled upward for the efficient removal of debris. Use of the inlet structure consistently decreased gas supersaturation in the spring water as it entered the fish production pond. By decreasing gas levels and maintaining water flows, potentially hazardous fish health issues can be avoided by using this structure. In addition, this relatively inexpensive and simple device will greatly reduce the labor required for removing debris compared to traditional screens.
