非轴对称拉延过程的有限元分析

本文利用弹塑性有限元法分析了非轴对称拉延过程。计算中选用了考虑横向剪切影响的曲壳单元,提出了对板料随位置和加载变化而改变的边界条件的处理办法,得到了拉延过程中板料凸缘部分金属流动规律、工件剖面的几何形状,应变分布曲纹等等。将计算结果与实验进行了比较,取得了一致的规律性。     

由标准生成热计算含有化合物的二元系的活度

本文利用已知化合物的生成热,推导出了一个在含有化合物的二元体系,由相图计算活度的新公式:\\[{\\rm{dln}}{{\\rm{\\gamma}}_{\\rm{A}}}{\\rm{=-}}\\frac{{{\\rm{\\Delta}}{{\\rm{H}}_{\\rm{f}}}^{\\rm{0}}{{\\rm{N}}_{\\rm{B}}}}}{{{\\rm{R}}{{\\rm{T}}^{\\rm{2}}}{\\rm{(x}}{{\\rm{N}}_{\\rm{B}}}{\\rm{-y}}{{\\rm{N}}_{\\rm{A}}}{\\rm{)}}}}{\\rm{dT-dln}}{{\\rm{N}}_{\\rm{A}}}\\;\\;\\;\\;\\;\\;\\;\\;(1)\\]式中:ΔH_f⁰为化合物的标准生成热;x,y分别为化合物的化学计量系数;N_A、N_B分别为组元A、B的摩尔分数;γ_A、γ_B分别为组元A、B在液相线温度时的活度系数。
对已知活度值的Au—Bi二元体系,用文献[3]中公式及我们的公式进行了计算,其计算数值与实验数值符合较好,证实了用本公计算含有化合物的二元体系的活度是可行的。
我们用本公式计算了Al—La二元体系的活度,对预报的结果进行了初步分析。     

基于HP滤波的ARMA-ABCSVR-GABP网络流量预测

针对当前网络流量无法根据流量变化的特征进行预测,且通过单一或者组合模型依然得不到较高准确率的问题,提出一种基于HP(High-Pass Fliter)滤波的流量预测模型.基于高铁站流量数据日高夜低的周期特性以及流量波动增长的长期趋势,依据HP滤波将网络流量分解成周期序列及趋势序列.利用自回归-滑动平均模型(ARMA)对...     

DC-EAES-LF熔池电弧电渣加热过程的三维数值模拟

建立了非规范正交曲线坐标系下DC-EAES-LF炉电弧电渣加热过程三维数学模型,并进行联立耦合求解：速度场计算使用了矢性流函数方程和涡量输运方程;湍流模型采用引入Rechardson浮力修正项的k-ε双方程模型;温度场用非定常能量输运方程描述．现场测量的温度场与预报结果基本一致。     

流量非接触测量方法

提出了一种流量非接触式测量的新方法,即用管外加热套对被测管段加热,因管内流体的流动使其上下游产生温度差,由铂膜电阻将此温差转换成电阻差,从而实现了利用不平衡电桥测量管内流体速度及流量的新构想.     

低饱和场巨磁电阻金属多层膜Ni80Fe20/Cu的结构与磁电阻

采用磁控溅射方法,获得了具有低饱和场巨磁电阻的Ni₈₀Fe₂0/Cu由金属多层膜.在室温下,其磁电阻和层间耦合状态随Cu层厚度的增加呈振荡变化.在Cu层厚度tcu=1.0nm,2.2nm时磁电阻出现2个峰值分别为19.4%和11.7%,饱和场约为6.4×10⁴ A/m和8×10³ A/m,低温下(77K)磁电阻为对33.2%和27.6%.系统地研究了NiFe层厚度和周期数对多层膜磁电阻的影响.用真空退火方法对样品进行热处理,发现多层膜的磁电阻性能有明显改变.     

转炉热喷补机喷射系统的分析

论述了转炉热喷补技术的发展与应用,在对宝钢转炉热喷补机进行充分调查的情况下,对喷补机喷射系统的结构及参数作了分析,提出了有关参数的确定与计算方法.     

Achieving C/CuO microfiber composites with efficient microwave absorbing performance at low thickness

Journal of Materials Science: Materials in Electronics - The carbon fibers with low density still face significant microwave absorbing application issues due to their high dielectric constant....     

Adsorption of oxytetracycline from aquaculture wastewater by modified carbon nanotubes: kinetics,isotherms and thermodynamics

Abstract

In the present study, lanthanum modified carbon nanotubes (La-CNTs) were prepared by the impregnation method and used as adsorbents to remove oxytetracycline (OTC) from aquaculture wastewater. La-CNTs were characterized by SEM, EDS, XRD, BET analysis. The effects of adsorbent dosage, concentration of OTC, adsorption time, pH and interfering ions on the adsorption of OTC by La-CNTs were investigated. The optimum adsorbent dosage, OTC concentration, adsorption equilibrium time and pH for OTC adsorption by La-CNTs are 0.03?g, 20?mg/L, 180?min and 7, respectively. The outcome of the kinetics studies showed a significant linear correlation between the experimental results and the quasi-second-order kinetics model. As an adsorption isotherm model, the Langmuir model showed a very good consistency with the adsorption of OTC by La-CNTs, as the maximum adsorption quantity reached 117.23?mg/g. Through the thermodynamic analysis showed that the adsorption of OTC by La-CNTs was an endothermic process of entropy increase, which occurs spontaneously. The predominant forces promoting this adsorption were van der Waals force, π-π electron donor-acceptor interaction, and electrostatic interaction.     

Smart fabric strain sensor comprising reduced graphene oxide with structure-based negative piezoresistivity

Journal of Materials Science - Fabric strain sensors have attracted significantly increased interest as wearable electronics for their flexibility, softness, and wearing comfort in recent years....