多层频率选择表面的分析

本文利用矩量法和广义散射矩阵理论分析了多层频率选择表面的散射特性。通过引入广义波导概念,可以统一分析单元形状为任意的多层频率选择表面。作为示例,计算了几种不同结构频率选择表面的散射特性,结果与文献中给出的数据相符。     

Powder Deposition in Three Parallel-Oriented Dies of Different Shapes

Uniformity of bulk density distribution during the die filling process is required to minimize quality problems, such as distortion and cracking, for powder compacts. Understanding the die filling process is necessary in ensuring a uniform powder deposition. The second-generation pressure deposition tester (PDT-II) was used to investigate the deposition process and final pressure distribution of powder filling in toroidal, cylindrical, and E-shaped dies. All tests were conducted using a spray-dried free-flowing granular powder. The results indicated that for toroidal dies: (1) the area around 0° orientation (the leeward end) had the highest pressure values (1186.7 to 2498.0 Pa), with the average pressure values of the remaining area 353.7-648.0 Pa; (2) the pressure distribution was symmetrical about the centerline parallel to the feed shoe movement direction; (3) the highest feed shoe speed (500 mm/s) led to the most nonuniform pressure distribution among the three speeds; (4) higher feed shoe speed did not always result in higher final pressure values; and (5) the right die tended to have higher final pressure values (215.0 to 2498.0 Pa) than the center die (95.4 to 2052.5 Pa). For E-shaped dies: (1) the final pressure values of the middle leg (308.9 to 760.7 Pa) were higher than those of the left and the right legs (148.9 to 530.3 Pa); (2) the area along the backside had the highest final pressure value (1054.6 to 1303.8 Pa); (3) the pressure distribution was symmetrical about the centerline parallel to the feed shoe movement direction; and (4) neither the center die nor the right die always had higher pressure values than the other one at all locations. Comparison between cylindrical and toroidal dies indicated that: (1) neither of the two die shapes (cylinder and toroid) led to consistently higher or lower final pressure values at all locations and (2) for all three feed shoe speeds, the toroidal die had higher average final pressure values in the 0° orientation.     

Numerical modelling for scattering of waves in three-dimensional cracked material

In this paper, a mathematical model is proposed for the problem of the scattering of plane waves in a three-dimensional cracked materials. Instead of obtaining closed-form solutions as in conventional theoretical analysis methods, this approach, called the Equivalent Nodal Force (ENF) method formulates the mechanical effects of cracks as an equivalent nodal force in a numerical procedure, and physically translates cracked material into an equivalent continuous one. Several mechanical relations between waves and cracks are evident from this method. Also the results of several numerical calculations are presented and these are compared with those obtained by the conventional methods.     

厚度控制技术在中厚板轧制生产中的应用

本文探讨了影响中厚板厚度波动的因素，结合安钢中板厂2800mm轧机按合同轧制一批交货重量不大于理论重量船板的生产实践，总结了实际生产中实现高精度厚度控制的有效方法。     

Ideal-gas thermodynamic properties for natural-gas applications

Calculating caloric properties from a thermal equation of state requires information such as isobaric heat capacities in the ideal-gas state as a function of temperature. In this work, values for the parameters of thec _p ⁰ correlation proposed by Aly and Lee were newly determined for 21 pure gases which are compounds of natural gas mixtures. The values of the parameters were adjusted to selectedc _p ⁰ data calculated from spectroscopic data for temperatures ranging from 10 to 1000 K. The data sources used are discussed and compared with literature data deduced from theoretic models and caloric measurements. The parameters presented will be applied in a current GERG project for evaluating equations of state (e.g., the AGA 8 equation) for their suitability for calculating caloric properties.     

地震复合波地质属性的研究方法

在地震资料解释中,地震复合波的地质属性问题一直没有得到很好地解决。本文针对松辽盆地砂泥岩薄互层的地质特点,提出了用波形合成追踪法研究地震复合波地质属性的方法。该方法在地震复合波正演合成过程中有五个可以识别的特征界面,其中 C 界面是地震复合波形成的主导界面;C 至 D 界面间的地层为形成地震复合波的主要地层。因此,找准 C 界面深度是建立地震复合波与钻孔地层间有机联系的关键,对地震地质层位准确标定和利用地震剖面复合波波形信息进行岩性预测极为重要。文中的应用实例表明,用该方法在松辽盆地较好地建立了地震信息与地质信息间的对应关系,解决了一些疑难地质问题,取得了较好的勘探效果。     

�¸�������в������Ȼ�����꾮�ٶȵ�;��

本文针对天然气井提高钻井速度问题,总结分析了盆地中部井身结构,水力、机械参数,聚合物钻井液,正注反挤固井等工艺技术对该地区钻速的影响。指出提高天然气井钻井速度,必须搞好系统工程,形成配套技术。     

一种新型声波降粘防蜡装置

新型声波降粘防措装置由上、下接头、振动簧片和收缩喷嘴构成。装置安装在抽油泵泵简之下，尾管之上，在压差作用下井下流体以较大速度从装置的喷嘴射出，冲击振动簧片，产生机械振动声波，油水混合液在声波中产生相应的声波力学效应和分散乳化作用等，使混合液在油管内的粘度降低，蜡晶不易聚集长大，从而达到降粘防蜡延长油井热洗周期的目的。室内试验及现场近20口井的应用情况表明，这种装置具有结构简单、成本低廉、应用方便等特点，具有明显的降粘防蜡效果。     

Study on Factors Affecting the Structure of High SpeedSteel Ingot Produced by ESR

ＳｔｕｄｙｏｎＦａｃｔｏｒｓＡｆｆｅｃｔｉｎｇｔｈｅＳｔｒｕｃｔｕｒｅｏｆＨｉｇｈＳｐｅｅｄＳｔｅｅｌＩｎｇｏｔＰｒｏｄｕｃｅｄｂｙＥＳＲＬｉＺｈｅｎｇｂａｎｇ；ＣｈｅＸｉａｎｇｑｉａｎＡｂｓｔｒａｃｔ：Ｔｈｅｉｎｆｌｕｅｎｃｅｏｆｔｈｅｍｅｔａｌｐ...     

冷轧厂酸洗机组3号横剪大流量中高压液压系统设计方案探讨

在宝钢２０３０ｍｍ冷轧厂酸洗机组中，为了满足厚规格ＩＦ钢的生产，拟将原有的气动式剪切机改成液压式剪切机。为此，设计了一套中高压大流量的液压系统以满足３号横剪大剪切力（最高达７００ｋＮ）和快速剪切（３秒／次）的需要。由于采用了蓄能器增速回路和二通插装阀控制技术，使该液压系统较传统的剪切机液压系统具有响应速度快、体积小、重量轻、发热少和降低电机能耗等优点。