数控加工复合循环功能与子程序编程的特点及其应用

零件的数控加工,为了简化数控加工程序,既可以利用复合循环功能编程,又可以应用子程序技术编程.通过对复合循环功能编程与子程序编程的比较得知,应用子程序编程利大于弊,有利于保证零件的加工质量,提高加工效率,降低生产成本.     

全球变暖背景下内蒙古地区沙尘暴频次变化的预估

构建一个基于BP神经网络的统计模型,利用CMIP5模式中历史情景和未来情景的预估数据,重建1860—2100年内蒙古地区春季沙尘暴频次(分辨率达到日尺度)序列.在此基础上,研究内蒙古地区沙尘暴未来长期变化特征.结果表明,在未来情景RCP2.6和RCP8.5中,与历史时期(1860—2005年)相比,内蒙古地区沙尘暴频次...     

DCPD/C9热聚型石油树脂的聚合工艺研究

提取乙烯裂解副产物C5馏分中的双环戊二烯馏分，与裂解C9、C5馏分按不同配比混合，通过自由基聚合反应得到热聚型石油树脂，并确定了热聚型石油树脂的工艺参数。     

Influence of thermal-decomposition temperatures on structures and properties of V2O5 as cathode materials for lithium ion battery

Submicron spherical V2O5 particles with a uniform size and a lower crystallinity were successfully synthesized by a chemical precipitationthermal decomposition technique using the commercial V2O5 powders as starting material. The crystal structure and grain morphology of samples were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM), respectively. Electrochemical testing such as discharge–charge cycling(CD) and cyclic voltammetry(CV) were employed in evaluating their electrochemical properties as cathode materials for lithium ion battery. Results reveal that the crystallinity and crystalline size of V2O5 particles increased when the thermal-decomposition temperature increased from 400 ℃ to 500 ℃, and their adhesiveness was also synchronously increased. This indicate that the thermaldecomposition temperature palyed a significant influence on electrochemical properties of V2O5 cathodes. The V2O5 sample obtained at 400 ℃ delivered not only a high initial discharge capacity of 330 m A h g-1and also the good cycle stability during 50 cycles due to its higher values ofα in crystal structure and better dispersity in grain morphology.     

有限余相关模及模和环的有限余相关维数

给出了有限余相关模的刻画,用有限余相关模刻画了余Noether环和V－环,给出了余正则环为V－环的条件和遗传环为半单环的一个条件。定义了模和环的有限余相关维数,研究了它们的一些性质,对于余凝聚环,这种维数具有一些好的性质。     

Comparative analysis by simulating and testing pole impact for hot stamping front crossbeam of automobile

Hot stamping 22MnB5 steel plate with ultra-high strength has been widely used for body structural members in consideration of automobile safety and lightweight.This paper presents a verification program of simulating and testing pole impact in order to verify if the front crossbeam reinforcement assembly can meet the design requirements,reduce the overall vehicle simulation and test cost and shorten the operation period.In the same condition,the simulation proved conforming to the design requirements;however,the bumper cracked at the impacting point in the course of pole impact test.The analysis of the crack by optical microscope,Vickers and scanning electron microscope indicates that mixture of ferrite,bainite and martensite was produced in the weld heat-affected zone of the 340/590DP tow hook holder and the 22MnB5 front crossbeam;therefore,their hardness and mechanical property were reduced obviously,so that they fractured when impacted.No welding process with continuous weld but spot welding or other bonding method may be employed for the reason that the capacity of the 22MnB5 steel plate in the weld heat-affected zone was reduced obviously.     

高效液相色谱法测定嘎日迪-5味丸中绿原酸的含量

目的：建立测定蒙药嘎日迪-5味丸中绿原酸含量的反相高效液相色谱法．方法：用ODS C18色谱柱,流动相为乙腈-水-冰醋酸（11．5：88．5：2）,检测波长318nm,流速为1ml／min．以外标法测定了嘎日迪-5味丸中绿原酸的含量．结果：绿原酸在4．5～22．5μg/ml浓度范围内呈良好的线性关系．平均回收率为98．1％,RSD=2．2％（n=5）．结论：本法简便,可靠,可作为蒙药嘎日迪-5味丸的含量测定方法．     

石油馏分在常、减压下汽-液平衡常数的计算

在1.33～101.32 kPa下测定了175个窄馏分油相平衡常数。介绍了测试装置,进行了计算。结果表明:将这类油作为理想体系是不恰当的。以Maxwell-Bonnel图拟合式、对比态Antoine方程及Pitzer-Riedel关联式分别求算饱和蒸汽压P°,并随之用Raoult K值(K=P°/P)计算窄馏分相平衡常数,均未取得满意的结果。提出了两种修正模型,并由实测平衡常数回归修正模型的常效。推荐使用修正的对比态Antoine方程进行低压体系馏分油的汽液平衡计算。该修正模型对温度预测的平均绝对误差为3.45℃;平衡常数预测的平均相对误差为7.32%。     

荧光猝灭法测定污水中痕量亚硝酸盐

本文利用亚硝酸根离子与罗丹明6G在酸性介质中的亚硝化反应,使罗丹明6G荧光猝灭,并由此建立了一个简单、快速、选择性好的测定亚硝酸盐的新方法.此法成功地应用于污水中亚硝酸盐的测定。     

可压Euler方程的格子Boltzmann方法:二维情形

根据微观和宏观之间的质量、动量和能量守恒原理，构建了一个可用于模拟可压流体的D2V19格子Boltzmann模型，利用Chapman—Enskog分析可从该模型推导出宏观流体力学方程-Euler方程．利用该模型对三种典型激波管进行数值模拟并与Riemann解析解进行比较和分析，发现该模型能较好的捕捉激波，精度令人满意，证明了该模型对可压流体的适用性．该模型适用于气体多方指数为任意值的系统．