受干扰波相位测量的一种新方法

为了测量受噪声和谐波干扰的两个信号间的相位差，基于自适应带通滤波器（ABF）和测量信道交换技术，提出了一种新的测量方法。ABF采用可编程开关电容滤波器（PSCF）和锁相环，明显地抑制了噪声和谐波干扰，频率跟踪范围超过四个倍频程（0．5Hz-6kHz）。用微处理器控制4个开关来交换测量信道，可以基本上消除测量通道引入的附加相位移。两种方法结合提高了相位差的测量精度。实验说明了该测量方法的有效性，该方法也适合于被测信号为慢时变情况。     

中频数字化及数字式正交解调

本文介绍用数字式下变频法实现中频正交解调的基本原理及主要性能。     

Impurity Distribution Behavior in Caprolactam Extraction with Environmentally Benign Mixed Solvents

In a previous study a solvent mixture of heptane containing 40 mass % heptanol was selected as an alternative in the industrial extraction of caprolactam to replace benzene, toluene, or chlorinated hydrocarbons. This work reports the equilibrium distribution ratio of caprolactam and four model impurities of organic nature, namely, cyclohexanone, aniline, n‐methylcaprolactam, and cyclohexane‐carboxamide, comparing the mixed solvents with toluene as a reference. The resulting phase equilibria were interpreted using the equilibrium stage model. Based on these calculations it was found that, compared to toluene, the co‐extracted fraction of cyclohexanone and aniline was higher, that of n‐methylcaprolactam was comparable, and that of cyclohexane‐carboxamide was lower using the mixed solvent. Overall, the mixed solvent reduced the fraction of co‐extracted impurities by almost 10 %.     

A Method of Combined SHPB Technique and BP Neural Network to Study Impact Response of Materials

Abstract:  A new method combining the split Hopkinson pressure bar (SHPB) technique with the back-propagation (BP) neural network program is proposed. By this method, the treated strain wave signals become smooth with less noises induced by the transverse inertia. Moreover, the dynamic rate-dependent constitutive behaviour of materials can be identified, without any pre-assumption of a constitutive model. It is found that by taking the experimentally measured data of strain, strain rate and time as 'input' and the corresponding data of stress as 'output' of the BP neural network, the dynamic constitutive behaviour with internal damage or phase transformation evolution is easy to be identified, where the time could represent either the internal damage evolution or phase transformation process accompanied with the deformation process. It is emphasised that the data learnt by the BP neural network must include both loading and unloading processes, if the whole loading and unloading response is to be correctly predicted. The comparisons between the predictions and experimental results are in good agreement for both polyamide (PA) polymer (as an example of nonlinear viscoelastic materials) and Ti–Ni alloy (as an example of superelastic materials with stress-induced phase transformation).     

水冷热模法离心铸造大口径球铁管用管模涂料

阐述水冷热模法管模涂料的组成。说明了耐火基料，悬浮剂、粘结剂，减水剂的各自作用机理，提出了合理的涂料配方、合适的喷涂方式。     

Studies on the corrosion behavior of cerium-implanted zircaloy-4 with GAXRD

In order to study the influence of cerium ion implantation on the aqueous corrosion behavior of zircaloy-4, specimens were implanted by cerium ions with a fluence range from 1×10¹⁶ to 1×10¹⁷ ions/cm² at maximum 150°C, using MEVVA source at an extracted voltage of 40 kV. The valence and elements penetration distribution of the surface layer were analyzed by X-ray photoelectron spectroscopy (XPS) and auger electron spectroscopy (AES) respectively. Glancing angle X-ray diffraction (GAXRD) was employed to examine the phase transformation due to the cerium ion implantation in the oxide films. Three-sweep potentiodynamic polarization measurement was employed to value the aqueous corrosion resistance of zircaloy-4 in a 1 N H₂SO₄ solution. It was found that a significant improvement in the aqueous corrosion behavior of zircaloy-4 implanted with cerium ions compared with that of the as-received zircaloy-4. The improvement effect will declined with raising the implantation fluence. The bigger is the fluence, the less is the improvement. Finally, the mechanism of the corrosion behavior of the cerium-implanted zircaloy-4 is discussed.     

管内材料高温放气性能的测试及应用研究

管内材料放气性能的优劣直接影响着整管的性能和寿命.本文简介了测试管内材料高温放气性能的原理、装置和方法.文中列举的几项应用实例表明,本项测试结果对产品质量控制、工艺技术改进和材料进厂检验及国产化攻关都具有指导意义.     

圆管流动的二次转捩

利用直接数值模拟方法求解N-S方程来研究空间发展的圆管转捩,计算中雷诺数Re选定为3000。在局部壁面引入的周期性吹吸(PSB)扰动作用下,圆管中首先出现了塞流结构,并向下游迁移,同时有稳定的流向条带结构形成;在塞流结构离开计算域后,随着扰动的不断发展,流向条带结构逐渐破裂失稳,圆管流动出现了第二次转捩,这是一种新的转捩形式,我们称之为“二次转捩”。     

TCA785移相控制芯片应用方法的改进

TCA785是德国西门子公司生产的一种性能优秀的移相控制芯片 ,该器件具有温度适应范围宽 ,对过零点的识别更加可靠 ,输出脉冲的整齐度更好 ,移相范围更宽等优点 ,此外 ,由于TCA785的输出脉冲宽度可以手动自由调节 ,因此 ,该器件可广泛应用在晶闸管控制系统中。文章根据TCA785芯片的使用特点以及在逆变器实际运用中可能出现的一些问题 ,提出了一种改进的设计方法     

Ni_(2.5)Mo_6S_(6.7)在有机电解液中的充放电特性

利用循环伏安法、交流阻抗法和充放电曲线等方法测定了Ni_(2.5)Mo_6S_(6.7)电极在1M LiClO_4,PC DME(1:1)有机电解质溶液中的可充电性。结果表明,该材料具有高的可充电性,有可能用作二次锂电池的正极材料。