基于三维织物的四元阵纺织天线

研制了一种新型的基于三维正交织物的纺织天线。该天线采用串馈四元阵形式,具有柔软性、易共形的性能,除了具有天线的功能,还具有纺织结构的功能。通过实验测定了天线的带宽、增益等指标。实验证明,该天线带宽为1.43~1.54 GHz,最大增益为7 dB,其尺寸为428 mm×155 mm。实验验证了新型天线的实用性。     

锅炉汽包水位的复合控制研究

针对工业生产中锅炉汽包的水位控制问题,分析了3种影响锅炉汽包水位控制的因素：给水扰动、蒸汽量扰动、燃料量扰动.介绍了锅炉汽包水位的3种控制方案：单冲量控制、双冲量控制和三冲量控制.对这3种控制方案比较后认为,锅炉汽包水位的三冲量控制是更合理的控制方案.使用和利时MACSV5.2.4软件进行组态,按照项目实施的过程,进行测点统计、控制器正反作用判断,并按照锅炉水位三冲量控制方案进行编程和画图.在生产中,工艺人员只在图形上操作,即可完成对锅炉汽包水位的控制.     

用于锅炉补给水处理的多级膜组合工艺及应用示范

超滤、纳滤、反渗透及EDI是实用性先进功能膜材料技术,高效节能,在锅炉补给水处理中应用潜力巨大。与目前所采用的单一膜工艺相比,多级膜组合处理工艺具有出水品质更高、无二次污染等明显优势。本研究以华纺股份有限公司的锅炉补给水系统工程系统为例,具体分析了超滤-反渗透-EDI多膜组合工艺、膜器系统及其在锅炉补给水处理中的效果。实际运行结果表明,该组合工艺能高效地去除水中盐类及小分子有机物,充分满足锅炉补给水的各项水质标准,而且具有运行周期长、出水水质稳定、连续出水等优点。     

给水泵失电导致机组停机的技术分析

针对一台200 MW火力发电机组电动给水泵突然失电后引起直流锅炉灭火、机组停机事故,从给水泵及直流锅炉的水动力特性方面着手,分析了事故过程和事故原因,并提出了相应的安全技术防范措施,以确保机组安全稳定运行.     

Control of interior surface materials for speech privacy in high‐speed train cabins

The effect of interior materials with various absorption coefficients on speech privacy was investigated in a 1:10 scale model of one high‐speed train cabin geometry. The speech transmission index (STI) and privacy distance (r_P) were measured in the train cabin to quantify speech privacy. Measurement cases were selected for the ceiling, sidewall, and front and back walls and were classified as high‐, medium‐ and low‐absorption coefficient cases. Interior materials with high absorption coefficients yielded a low r_P, and the ceiling had the largest impact on both the STI and r_P among the interior elements. Combinations of the three cases were measured, and the maximum reduction in r_P by the absorptive surfaces was 2.4 m, which exceeds the space between two rows of chairs in the high‐speed train. Additionally, the contribution of the interior elements to speech privacy was analyzed using recorded impulse responses and a multiple regression model for r_P using the equivalent absorption area. The analysis confirmed that the ceiling was the most important interior element for improving speech privacy. These results can be used to find the relative decrease in r_P in the acoustic design of interior materials to improve speech privacy in train cabins.     

一种新型宽频带圆极化球螺旋馈源

提出了一种新型宽频带圆极化球螺旋馈源,给出了球面螺旋的几何关系和理论分析,得到了辐射场的解析关系和不同模式下远场的表达式.运用该理论进行工程设计并进行了实际测试,测试结果与理论分析的吻合,验证了理论分析和工程设计的正确性.与传统圆极化馈源相比,该馈源具有结构简单、频带宽、体积小等优势.     

Two types of a passive safety containment for a near future BWR with active and passive safety systems

The paper presents two types of a passive safety containment for a near future BWR. They are named Mark S and Mark X containment. One of their common merits is very low peak pressure at severe accidents without venting the containment atmosphere to the environment. The PCV pressure can be moderated within the design pressure. Another merit is the capability to submerge the PCV and the RPV above the core level. The third merit is robustness against external events such as a large commercial airplane crash. Both the containments have a passive cooling core catcher that has radial cooling channels. The Mark S containment is made of reinforced concrete and applicable to a large power BWR up to 1830 MWe. The Mark X containment has the steel secondary containment and can be cooled by natural circulation of outside air. It can accommodate a medium power BWR up to 1380 MWe. In both cases the plants have active and passive safety systems constituting in-depth hybrid safety (IDHS). The IDHS provides not only hardware diversity between active and passive safety systems but also more importantly diversity of the ultimate heat sinks between the atmosphere and the sea water. Although the plant concept discussed in the paper uses well-established technology, plant performance including economy is innovatively and evolutionally improved. Nothing is new in the hardware but everything is new in the performance.     

COOLING AND SOLIDIFICATION IN THE PRESENCE OF RECIPROCATING NON-NEWTONIAN SHEAR FLOW: THE LIVE FEED INJECTION MOULDING PROCESS

The cooling and solidification of a non-Newtonian material in the presence of reciprocating flow is analysed. Finite difference solutions are obtained for a transient I-space-dimensional model of a shear thinning material with temperature dependent properties, contained between plane parallel surfaces to which it looses heat by conduction in the presence of periodically reversing flow. This situation is relevant to live feed injection moulding - an advanced technology for thermoplastics processing - in which alternating direction shear is imposed on melt in the mould cavity during the holding and packing stages. Interest centres on the effects of flow on cooling and solidification and the development of frozen-in strains, which have important implications for the control of material alignment and mechanical properties of mouldings. The governing dimensionless parameters are identified and their influence investigated in a series of numerical simulations, where the parameters range over the following values: Pearson number 0.5-5.0; Brinkman number 0.001-1.0; Stefan number 0.1 - 1.0; Power Law Index 0.2-1.0; dimensionless flow reversal time 0.01-1.0. Two operating modes are considered: (1) fixed applied pressure gradient, with a falling flow rate; (2) flow rate initially fixed, followed by a falling flow rate period at a fixed limiting pressure gradient. In mode 1 operation viscous heating does not significantly influence cooling rates, but in mode 2, for high Brinkman numbers, a dynamic equilibrium temperature field can be attained. Complex profiles of frozen-in material strain through the thickness of the moulding are predicted. In mode 1 operation the magnitude of the principle stretch rises to a peak close to the mould walls, and falls in a series of oscillations to unity (zero deformation) on the centre plane. High values of the Pearson number or low values of the Power Law Index damp these oscillations. In mode 2 operation sharply alternating regions of high and low strain are obtained indicating a structure with alternating layers of high and low material orientation.     

PVC多种原料路线并存有利于低御风险

国际环境对我国PVC生产有明显影响，尽管国内PVC需求在向1000万t/a发展，搞PVC新项目依然存在巨大风险，为减少风险，国家应鼓励多种原料路线长期共存。     

应用Excel97软件设计饲料配方

Microsoft Excel97中文版是Microsoft Office97中文版集成软件中最重要的家庭成员之一，可以广泛应用于报表处理、数学计算、工程计算、财务处理、统计分析、图表制作和日常事务处理等各个方面，同时还具有数据库处理和网络数据交换等功能。基于Excel97上述功能，我们探讨应用该软件进行饲料配方设计(拟主要应用其报表处理、数据共享、规划求解及函数等功能)，简化计算配方的繁琐过程，为饲料工作者实际应用时提供参考。