Premixed edge flame in a counterflow field with a stretch rate gradient

An edge flame was established in a counterflow field with a stretch rate gradient using twin rectangular burners which were misaligned by a few degrees. The stretch rate gradient was quantitatively defined as a function of the angle between the two burners and the distance from the edge of the burner, and thus the effect of stretch rate gradient on the behavior of the edge flame was investigated. The local chemical reaction rate at the edge of a CH₄/air flame was stronger than that at other parts of the flame. On the other hand, the reaction rate at the edge of a C₃H₈/air flame was weaker than that of other parts of the flame. The curvature of the flame edge of the CH₄/air flame was much larger than that of the C₃H₈/air flame. These results are thought to be due to the effect of the Lewis number. The ratios of the local stretch rate at the flame edge to the extinction stretch rate for planar twin flames with the same composition as the edge flame were 0.5 to 0.7 for the CH₄/air flame and 0.6 to 0.8 for the C₃H₈/air flame. These values were midway between those in the numerical simulation by Daou and Linan and those in the experiment by Liu and Ronney. Moreover, it was shown that an increase in the stretch rate gradient resulted in a lower local stretch rate at the flame edge. Behavior of the edge flames did not depend on the Lewis number of the mixture.     

矢量信道统计特性及仿真

研究了矢量信道在时域和空间域对信号的影响，即信号的快衰落特性。充分考虑了时延扩展，到达角，角度扩展，角度功率谱，多普勒效应等空域时域关键参数，并给出了仿真结果，对于研究矢量信道特性有重要意义。     

纺织品设计专业教学中学生发散思维培养

发散思维是一种创造性思维，常用于技术开发和产品设计。本文结合专业教学特点，从三个方面探讨如何训练纺织品设计专业学生的发散思维能力和如何运用发散思维。     

The quality and sensory attributes of cookies supplemented with fluted pumpkin (Telfairia occidentalis Hook) seed flour

Replacing wheatflour (WHF) with defatted fluted pumpkin (Telfairia occidentalis Hook) seed flour (FPF) at levels of 0–25% was investigated for its effect on chemical, physical, sensory and nutritional properties of cookies (biscuits). Protein quality was evaluated by using weanling albino rats fed a diet of cookies, which were formulated to supply 10% protein, with a casein diet as a control. Up to 15% substitution of WHF with FPF produced acceptable cookies with spread ratio, hardness, colour and flavour similar to the control (100% WHF) cookies. Use of higher levels (20–25%), however, resulted in reduction in these quality attributes. When WHF was replaced with 15% FPF, there was an increase of 84.6% in crude protein, 62.9% in calcium, 131.0% in potassium and 61.6% in phosphorus contents of composite cookies. There were no significant (P > 0.05) differences between the values obtained for protein efficiency ratio, net protein ratio and true digestibility of cookie diets containing 15–20% FPF, and casein when fed to rats.     

湍流扩散火焰数值模拟中若干影响因素的研究

应用CFD商业软件FLUENT,对火焰CVD法制备纳米颗粒的湍流扩散燃烧过程进行了数值模拟,分析了边界条件、物性以及辐射等因素对温度场的影响,尤其在低雷诺数下分子扩散对湍流计算中的不可忽略性进行了说明。计算的火焰形状与长度与实验中所观察的相符。     

具有梯形衬底结构半导体激光器的稳态特性分析

本文导出了梯形衬底半导体激光器的侧向扩展电流分布并提出了一种新的分析梯形衬底激光器稳态特性的模型。根据这一模型对梯形衬底双异质结结构和大光腔结构进行了分析和比较。分析结果和文献报道的实验结果很好地符合。     

镁离子改性MPP对玻璃纤维增强聚酰胺66的阻燃研究

研究了三聚氰胺聚磷酸盐（MPP）和镁离子改性三聚氰胺聚磷酸盐（Mg-MPP）分别对玻璃纤维增强聚酰胺66（PA66）的阻燃效果、热降解行为以及力学性能的影响。结果表明，在相同添加量的情况下，添加Mg-MPP比添加加PP有着更高的阻燃效率，氧指数提高了近16％。同时还提高了材料的热稳定性，起始分解温度提高26．5℃，残炭量增加。此外，Mg—MPP阻燃玻璃纤维增强PA66的力学性能明显优于MPP阻燃玻璃纤维增强PA66，其拉伸强度、弯曲强度和悬臂梁缺口冲击强度分别比后者提高了11．8％、6．5％和18．5％。     

新一代无线局域网技术在地震数据采集系统中的应用

遥测地震数据采集系统近年来发展迅速。然而有线地震数据采集系统和甚高频(VHF)无线地震数据采集系统依然存在各种问题，难以适应复杂地区作业。目前，应用扩频技术的无线局域网以其可移动性、高可靠性和低成本等优点普遍受到广大用户青睐。遥测地震数据采集系统也引入了这一高新技术。全无线网的遥测地震数据采集系统将是适应复杂地区万道地震勘探采集的一种良好仪器。文章介绍VIBTECH公司最新开发的“无限遥测系统”及其“蜂窝地震”新概念。在该系统中，数据传输使用TCP／IP802、11WLAN技术，具有高数据传输速率、高可靠性和低误码率；系统轻便可靠、功能强大，可以方便地应用于复杂地区的地震勘探采集。     

无卤阻燃增强PA66的研制及其在断路器外壳中的应用

采用红磷母粒阻燃玻璃纤维增强聚酰胺66(PA66),并添加适当的添加剂,制备了无卤阻燃增强PA66;考察了阻燃剂、增容剂及其它助剂对材料性能的影响。结果表明,该材料具有较高的力学性能、电绝缘性能和阻燃性能;用该材料制备的断路器外壳具有较好的阻燃性能及电绝缘性能,产品质量得到了客户认可。     

二元光学法在微透镜制作中的应用

对二元光学的产生和发展作了介绍,并阐述了二元光学元件之一的微透镜(microlenses)的设计、制作和测试方法以及它们的主要应用。微透镜的设计是基于已成熟的标量衍射理论;而其制作过程包括:计算机设计波面相位、产生掩模版、光刻或离子(束)蚀刻以及复制产生微透镜,其关键技术蚀刻方法有等离子蚀刻技术和反应离子蚀刻RIE(Reactive Ion Etching)技术;微透镜的测试主要包括衍射效率(diffractive efficiency)和点扩散函数(PSF)的测试,有直接法和间接法两种测试方法。微透镜可以微型化与阵列化,并且可以同微电子器件一起集成化,具有广泛的应用前景。