基于混合策略的转炉终点锰含量预测研究

摘要：转炉终点钢水锰含量预测,对原料添加和冶炼成本节约具有重要作用。针对凭经验预估的终点锰含量值与实际值较大偏差导致的生产成本升高的问题,建立了一种基于混合策略的改进型鲸鱼优化算法(IWOA)与最小二乘向量机(LSSVM)的转炉终点锰含量预测模型,引入柯西变异提高鲸鱼优化算法(WOA)跳出局部最优的能力;借助惯性权重增强鲸鱼算法局部搜索能力和收敛精度;提出差分变异以增加鲸鱼算法在探索末期的物种多样性和降低陷入局部最优概率。实验结果表明,IWOA LSSVM锰含量预测模型不仅在全局和局部寻优以及收敛速度有较大的提升,在误差性能指标方面优势明显,且预测误差于±0.01%间的命中率为93.3%。     

基于Matlab的圆锥齿轮差速器优化设计

差速器广泛应用于汽车行业。本文以圆锥齿轮差速器针体积最小为目标函数，建立了设计变量和约束函数。以具有2个行星齿轮的轿车差速器锥齿轮为例，给出了优化设计结果，探讨了利用MATLAB进行最优解求解的可行性。     

差温无模预成形锻造的有限元模拟研究

利用热力耦合有限元方法 ,对AISI10 4 5钢圆柱体坯料在环形加热源局部加热下的差温无模预成形锻造过程进行了模拟研究。模拟结果表明 ,在坯料中获得和控制大梯度分布的不均匀温度场是实现无模预成形锻造的关键。复杂零件成形必须合理地组合加热源和冷却源 ,以便产生所需的温度梯度场。在快速变形条件下 ,变形过程中的持续加热对金属的流动影响甚微 ,变形前的温度分布基本上决定了金属的流动 ,但在慢速变形条件下 ,变形过程中的持续加热对金属的流动产生一定的影响 ,其影响程度视零件复杂程度而异。从该文研究结果可以预见 ,差温无模锻造可以发展成为一种无模锻造制坯新工艺     

4-methoxy-2,6-bis(3,5-dimethylpyrazoyl)-1,3,5-triazine modified carbon paste electrode for trace Cu(Ⅱ) determination by differential pulse volt-ammetry

A differential pulse voltammetric method was developed for the sensitive and selective determination of Cu(Ⅱ) at 4-methoxy-2,6-bis(3,5-dimethylpyrazoyl)-l,3,5-triazine modified carbon paste electrode in 0.05 mol/L KHC8H4O4 solution (pH = 4.02). The oxidation peak of Cu(Ⅱ) was observed at 0.065 V(vs Ag/AgCl) by scanning the potential in positive direc-tion. The analysis procedure consisted of an open circuit accumulation step in stirred sample solution. It was followed by medium exchange to a clean solution and subsequently an anodic potential scan was affected to obtain the voltammetric peak. The current was proportional to the concentration of the Cu(Ⅱ) ion in a range of 1× 10-7-1×10-4 mol/L for 6 min accumulation; the most of metal ions did not interfere with the determination. The developed method was applied to Cu(Ⅱ) determination in coal-ash sample, the results agreed with that of atomic adsorption spectroscopy(AAS).     

一种用于制氧装置的单片机控制器

介绍了一种用于制氧装置的单片机控制器的功能及其硬件、软件设计。同时指出，这种控制器还可发展成为一种通用的多路定时控制器。     

用VB和Matrix VB混合编程求解偏微分方程

对MatrixVB作了简单介绍,通过一个具体的例子演示了如何在VisualBasic6 0(以下简称VB)中调用MatrixVB的函数,将MATLAB的强大的计算功能与VB在图形用户界面(Windows界面)开发方面的优势结合起来,有效地解决了复杂的偏微分方程的求解问题。     

Binary blends of polyethers with fatty acids: A thermal characterization of the phase transitions

A series of binary blends of poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), and polytetrahydrofuran (PTHF), characterized by similar average molecular weights, with selected fatty acids (capric acid, lauric acid, myristic acid, palmitic acid, and stearic acid) were prepared by melt mixing. Differential scanning calorimetry was applied to characterize the phase transitions of melting and crystallization, and a synergistic effect was found to occur for PEO/fatty acid blends, as evidenced by the values of the enthalpy of the phase transition. This effect was probably due to hydrogen bonding between PEO and the fatty (carboxylic) acids, which facilitated the formation of crystalline structures; an analysis of IR spectroscopy data showed a shift in the absorption bands of OH groups. The morphology development of the PEO/carboxylic acid blends, as observed with polarizing light microscopy, could be described as spherulitic growth with spontaneous selection of the lamellar thickness. The textures of the individual fibrils, consisting of stacks of several tens of lamellae corresponding to PPO and PTHF, were less regular than the texture of PEO and showed large macroscopic heterogeneity. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 861–870, 2003     

Modification of phenol–formaldehyde resol resins by lignin,starch, and urea

Lignin‐based chemicals, starch, and urea were used as modifiers for phenol–formaldehyde resol resins. The effects of the addition stage of the modifiers used in the synthesis of the resins and the type of modification reagent on the structures of the resins and their molar masses and reactivities were investigated. The modifications with corn starch and lignin promoted condensation; this was verified by increased molar masses and high ratios of methylene bridges to the sum of free ortho and para aromatic groups with respect to the corresponding reference resin without a modification reagent. The later the modifier was added to the resin condensation mixture, the more methylene bridges were formed with respect to the amounts of free ortho and para aromatic groups. In addition, when urea or wheat starch was added in the later condensation stage, the final condensation also reached high stages. The modifications with lignosulfonate and starch, as well as the early addition of urea, enhanced p–p′ bridge structures. The lowest condensation stage and, therefore, the highest reactivity were found when wheat starch was added with the starting reagents. The curing heat of the wheat‐starch‐modified resins decreased according to the deferred addition point of starch. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 582–588, 2003     

SEQUENTIAL LOOP CLOSING IDENTIFICATION OF MULTIVARIABLE PROCESSES USING THE BIASED RELAY FEEDBACK METHOD

Each controller in multiloop control systems for multivariable processes can be tuned sequentially with the ultimate information for the paired input and output while former loops have been closed, and hence, single-input single-output autotuning methods can be applied. In this sequential autotuning for multiloop control systems, several iterations are usually required for better control performances. Especially when pairings are undesirable, the autotuning sequences should be repeated with correct pairings, which result in long field experiments. Here, to avoid this drawback, a simple method to identify process models while loops are being sequentially tuned is proposed. The identified models can be used to correct pairings of multiloop control systems and to improve tuning performances without several field iterations. In addition, they can be used to obtain model-based control systems such as decoupling control systems.     

Characterization of the thermal properties of PLA fibers by modulated differential scanning calorimetry

Polylactide (PLA) has been melt spun to produce multifilament continuous yarns. The thermal characteristics of PLA filaments have been investigated using modulated differential scanning calorimetry (MDSC). With MDSC, it is possible to separate the different thermal events and to analyze them more precisely. The influence of hot drawing on thermal properties of PLA filaments has been studied. Hot drawing promotes an increase of glass transition temperature (T_g) and a decrease of heat capacity. The cold crystallization spreads on a larger range of temperature and the peak occurs at a lower temperature. The initial degrees of cristallinity of PLA filaments have been calculated thanks to the reversing and non reversing curves of MDSC. Tensile properties of PLA filaments are also investigated.