Influence of the stress,strain, and temperature on the surface roughness of an AlSl 52100 steel due to an orthogonal cut

In recent years, the finite element method (FEM) has become the main tool for simulating the metal cutting process because research based on trial and error is time consuming and requires high investment. Early studies were done by different investigators. In this research AISI 52100, hardened steel (62 HRC) was selected for an orthogonal machining process as well as metal cutting simulation using the software DEFORM-2D. This software is based on a forging process and has been adapted to an orthogonal machining process. The results of simulated cutting forces were compared with experimental cutting force data to validate the orthogonal cut simulation. Also, the surface roughness was measured, and the influence of the stress, strain, and temperature on the surface roughness was studied.     

SMB色谱分离过程计算机仿真

针对模拟移动床(SMB)综合速率模型，采用有限元法和正交配点法分别对柱向和颗粒径向模型进行离散化，利用MatLab ODE求解器对SMB过程进行数值求解。通过仿真，验证了该方法的可行性。     

醇-水法制备纳米NiO粉末的正交实验研究

纳米NiO粉末具有良好的催化性能、热敏性能及在各种材料中的加工性能,因而被广泛地应用在催化剂、磁性材料、电子元件材料等方面,是一种很有前途的新型功能材料。选用Ni(NO3)2.6H2O为原料,以NH4HCO3为沉淀剂,在醇-水介质中制得了纳米NiO粉末。通过扫描电子显微镜(SEM)对NiO粉末进行了表征。实验过程中,按正交表L8(27)安排了正交实验,通过方差分析确定了醇-水制备纳米NiO粉末的最佳煅烧时间、煅烧温度和醇-水比,并确定了各因素对制备过程的影响程度。     

利用粉煤灰生产SiC陶瓷原料

利用粉煤灰部分或全部代替石英砂,配以适量的锯末,在高温炉中特定的烧成制度下,采用SiO2-C还原法将粉煤灰中的二氧化硅与锯末中的碳结合制取高性能的SiC陶瓷原料。利用正交实验对合成工艺中的合成温度、保温时间、碳过量数进行了设计和探索性实验,并对合成产物中的碳化硅的含量进行了测试。研究表明,在经催化剂(FeCl26H2O)浸泡12小时,加入2%矿化剂,在1380℃的合成温度下,保温时间2小时,碳过量10%的情况下,生成的SiC陶瓷原料中SiC的含量在53.6%以上。     

DECOUPLER DESIGN AND CONTROL SYSTEM TUNING BY INA FOR DISTILLATION COMPOSITION CONTROL†

Six distillation column models have been used in studies of the usefulness of the Inverse Nyquist Array (INA) method for design of dual composition control for distillation. Five of the column models are experimental, one describing an industrial column, the others four pilot plants. One column model is obtained by modeling from first principles.

The control strategies investigated and compared are multiloop SISO, 2-way decoupling and l-way decoupling. The control variables are the standard ones, i.e. reflux flow and boilup.

In most of the cases INA has been found to be a useful tool for design of the loops and for comparison of the different control approaches. INA has also been found to be useful for simultaneous tuning of the decouplers and the feedback controllers.

For 2-way decoupling the criterion to minimize interaction at the critical frequency for each primary feedback loop has been found useful in most, but not all, cases. The scheme can be designed by pure gains in the decouplers and there is no reason to introduce dynamics into the decouplers—the systems studied are already sufficiently rich in dynamics.

INA has been found to be a suitable vehicle for the choice between the two possible l-way decoupling schemes.

With the design approach taken, l-way decoupling has been found to provide considerably better control quality than 2-way decoupling in two of the six systems, the differences in control quality being small in the other cases.

The effect of model mismatching on the results, caused e.g. by process nonlinearities, is discussed and simple rules to decrease the parameter sensitivity for 2-way decoupling schemes are given. When model mismatching is considered, the advantage of l-way decoupling over 2-way decoupling seems to increase.

One deficiency of the INA design as used in this paper is that it does not single out the design which is to be preferred on the grounds of robustness.     

纳米Al2O3,ZnO,CeO2,ZrO2对低温无铅熔块性能的影响

采用正交实验法,研究了在无铅基础熔块中,添加纳米Al2O3,ZnO,CeO2,ZrO2对其抗弯强度、维氏硬度及化学稳定性等性能的影响。结果表明:外加纳米氧化铝等可使无铅熔块抗弯强度提高30%,化学稳定性提高60%～80%,硬度提高10%左右。     

正交试验法在PAN原丝纺丝工艺中的应用

利用正交设计方法确定了PAN湿法纺丝过程中影响原丝性能最主要的因素。结果表明 :以计量泵转速、凝固浴温度、负拉伸以及蒸汽拉伸倍数作为考察对象 ,影响原丝性能的最显著因素是蒸汽拉伸倍数 ,其次是负拉伸。以负拉伸、第二拉伸、第三拉伸以及蒸汽拉伸的倍数作为考察对象 ,影响原丝性能最显著的是蒸汽拉伸倍数 ,负拉伸几乎没有影响。利用正交实验结果 ,适当调节蒸汽拉伸倍数 ,制得强度为 6.5～ 7.0cN/dtex ,线密度为 1.1～ 1.3dtex的原丝     

S-苄基-L-半胱氨酸的合成

由溴化苄和L-半胱氨酸直接合成S-苄基-L-半胱氨酸,通过正交试验及统计分析,检验了各影响因子的显著性,确定了最佳工艺条件为：反应时间2.5h,反应温度45℃,原料配比n（溴化苄）：n（L-半胱氨酸）=1：1.在此条件下反应,摩尔产率可达到95%.     

边坡可靠性分析的非线性有限元正交设计算法

非线性有限元正交设计算法，是借助于回归分析，用正交多项式拟合各岩石力学特性参数与各单元滑移面及岩体整体滑动安全余量间的函数关系，以评判边坡工程的可靠性。该法较蒙特卡罗法精度高，能满足工程计算的精度要求，且方法简单、计算时间少，不需改变有限元法的有关方程和计算程序，易为人们接受。     

相控阵雷达天线阵面记录回放系统

相控阵雷达广泛应用,其天线阵面对记录回放系统的数据速率要求提升。针对两种传统记录回放系统架构的不足,结合其优点,设计并实现了一种新型的基于FPGA的记录回放系统。该系统设计为板卡的形式,FPGA实现对硬盘的读写操作,采用自定义的文件系统对数据进行管理。经过测试,系统记录速度可以达到292 MB/s,回放速率为340 MB/s。实验结果表明,该记录回放系统性能稳定,通用性好,存储速率满足要求。