单基发射药孤石爆破特性实验研究

为研究单基发射药孤石爆破特性,利用直径和高度均为50 cm的水泥砂浆试块模拟孤石,开展了0.05～0.25 kg/m³单耗的单基发射药和乳化炸药孤石爆破实验,统计并分析了单基发射药和乳化炸药爆破试块的块度分布、破碎能及能量利用率随单耗的变化规律。结果表明：乳化炸药爆破孤石的最大块度随单耗的增加,但能量利用率变化不大。结合高速摄影观察对比单基发射药和乳化炸药爆破孤石的表面裂纹分布与扩展结果,发现单基发射药破岩模式与乳化炸药存在显著差异,其破岩模式是通过在炮孔内快速燃烧产生的高压气体使试块发生轴向和环向的拉伸破坏,而当试块完全开裂后剩余的发射药不再提供破岩能量。     

BOPP烟膜的摩擦系数研究

分析了工艺参数、原料性能和添加剂性能对烟膜摩擦系数的影响。重点讨论了不同类型添加剂的作用机理和作用效果。根据讨论结果,提出了BOPP烟膜的摩擦系数的控制方法和相关的注意事项。     

用过期“双迫”发射药改制射钉枪药的研究

文章分析了将过期“双迫”药改制成射钉枪药的可行性．实验表明,改制可采用球形药工艺,制品能满足射钉枪的使用要求．     

BOPP烟膜摩擦系数对香烟包装成型的影响研究

研究了BOPP烟膜摩擦系数在不同温度下对烟包运行的具体影响,探讨了不同类型BOPP烟膜对摩擦系数的不同需求,最后结合生产实际,提出了摩擦系数的最佳范围。     

少片钢板弹簧片间动摩擦系数计算方法研究

为研究钢板弹簧的片间动摩擦特性,提出一种少片钢板弹簧片间动摩擦系数计算方法。首先根据少片钢板弹簧的变形运动学特性,推导出少片钢板弹簧动摩擦系数与静摩擦系数的关系;然后分别基于力学法和能量法建立少片钢板弹簧静摩擦系数计算模型,根据摩擦功相等原理,得出板簧静摩擦系数计算方法;最后根据钢板弹簧动、静摩擦系数的关系,推导出少片钢板弹簧片间动摩擦系数计算方法。计算结果表明:摩擦系数的计算值和实际工况值基本吻合。以某企业实际板簧为例,对上述计算模型进行了实验验证。     

Pt-Ni/Nafion材料的制备及电致动性能研究

IPMC智能材料具有在低电压下产生较大形变和张力的特点,可作为新型的致动器。为了降低制备成本,采用渗透还原法制备了Pt-Ni/Nafion双金属层离子聚合物复合材料,确定了一套完整的制备工艺,测试了Pt-Ni/Nafion材料在不同驱动电压下的致动特性。结果表明,IPMC膜的形变随着直流电压的增大而增大,与初始位置的最大偏转角为47°;IPMC膜在正弦交流电压驱动下,形变随着电压幅值增大而增大,随着电压频率的增大而减小,并且电压输入与位移输出具有线性关系。     

间苯三酚栓剂在家兔体内的药动学研究

建立液相色谱-质谱联用(LC-MS)测定间苯三酚血药浓度的方法,并研究间苯三酚栓剂在家兔体内的药动学特征。取6只健康家兔直肠给予间苯三酚栓剂,于给药前和给药后5,10,15,18,20,25,30,45,60,90,120,180 min分别自耳动脉采血0.5 mL。采用LC-MS检测其血药浓度,安捷伦C18柱(4.6 mm×50 mm,1.7μm),流动相甲醇-水(含0.1%甲酸)梯度洗脱,三重串联四级杆质谱电喷雾(ESI)离子源,多反应监测(MRM)方式进行检测,离子化方式为正模式,进样量为2μL。采用DAS3.0药动学软件计算其在家兔体内的药动力学参数。间苯三酚在0.1725~5.52mg/L质量浓度范围内与其峰面积与内标峰面积的比值呈良好的线性关系。间苯三酚在家兔体内的药动学参数t_(1/2),T_(max),C_(max),AUC_(0-∞)分别为65.733 min,15 min,1.277 3 mg/L,39.993(mg·min)/L。该方法专属性强、精密度好,可用于间苯三酚家兔体内的药动学研究。间苯三酚栓剂在家兔体内代谢过程符合一室模型。     

柱前衍生化反相高效液相色谱法测定大鼠血浆中牛磺酸的含量及其药动学研究

建立一种测定大鼠血浆中牛磺酸含量的柱前衍生化-高效液相色谱法,并将其应用于牛磺酸在大鼠体内的药动学研究。采用柱前衍生化高效液相色谱法,以2,4-二硝基氟苯(DNFB)为衍生化试剂,以KH2PO3缓冲液(pH7.0):乙腈∶水(70∶15∶15,v/v)为流动相,经C18色谱柱(250mm×4.6mm×5μm)分离,柱温30℃,流速1.0m L/min,进样量为20μL,牛磺酸衍生物的紫外检测波长为360 nm,并以DAS2.0计算其药动学参数。大鼠血浆中牛磺酸在1.29~1 287.5μg/m L质量浓度范围内线性关系良好,r=0.999 9,最低定量限1.29μg/m L,主要药动学参数t1/2为(3.747±1.430)h,Cmax为(949.573±192.967)μg/m L,Tmax为(1.000±0.000)h,AUC0-t为(2 862.168±565.917)(mg/L)/h。该法简单、经济、灵敏,适用于牛磺酸血药浓度测定及药动学研究。     

绿原酸磷脂复合物固体分散体的体外溶出和药动学研究

为研究绿原酸磷脂复合物固体分散体(CA-PC-SD)的体外溶出以及体内药动学规律,采用HPLC法考察CA-PC-SD的体外溶出,大鼠灌胃后测定其血药浓度,并采用DAS 2.0软件分析计算药动学参数.结果显示:CA-PC-SD显著改善绿原酸磷脂复合物(CA-PC)的溶出效果,相较于原料药(CA)其相对生物利用度提高2.12倍.表明CA-PC-SD能显著改善CA-PC的体外溶出特性以及CA的口服生物利用率.     

结合面静摩擦系数的统计模型

基于粗糙表面形貌的统计参数,综合考虑微凸体的完全弹性、弹-塑性和完全塑性三种变形机制,建立了结合面静摩擦系数的统计模型。该模型反映了静摩擦系数是由接触材料性能参数、表面形貌统计参数以及法向载荷共同决定的。通过仿真研究了微凸体高度的随机分布、塑性指数以及法向载荷等因素对静摩擦系数的影响规律。结果表明,修正的指数分布相比简单的指数分布对高斯分布有着较好的近似,且预测值近似等于高斯分布预测结果的均值;静摩擦系数随着塑性指数的增大而减小且变化趋缓;法向载荷增大时,静摩擦系数呈现减小的趋势,但在双对数坐标系下最大静摩擦力仍与法向载荷呈线性正比的关系。     

Influence of roughness parameters on coefficient of friction under lubricated conditions

Surface texture and thus roughness parameters influence coefficient of friction during sliding. In the present investigation, four kinds of surface textures with varying roughness were attained on the steel plate surfaces. The surface textures of the steel plates were characterized in terms of roughness parameter using optical profilometer. Then the pins made of various materials, such as Al-4Mg alloy, Al-8Mg alloy, Cu, Pb, Al, Mg, Zn and Sn were slid against the prepared steel plates using an inclined pin-on-plate sliding tester under lubricated conditions. It was observed that the surface roughness parameter, namely, R _a , for different textured surfaces was comparable to one another although they were prepared by different machining techniques. It was also observed that for a given kind of surface texture the coefficient of friction did not vary with R _a . However, the coefficient of friction changes considerably with surface textures for similar R _a values for all the materials investigated. Thus, attempts were made to study other surface roughness parameters of the steel plates and correlate them with coefficient of friction. It was observed that among the surface roughness parameters, the mean slope of the profile, Del a(Δ _a ), was found to explain the variations best.     

Relationship between normal load and dynamic co-efficient of friction on rock-rubber wear mechanism

In this study, rubber compounds were produced in varying proportions of carboxylated acrylonitrile butadiene rubber (XNBR) and natural rubber (NR) and the parameters such as cure characteristics, wear behavior against various surfaces at different normal loads, and frictional works were tested. The tensile strength and dynamic co-efficient of friction of sample containing 80 wt.% of XNBR was high compared to other samples by 2% and 10% respectively. The results of XNBR and NR vulcanizates under normal pressure ranging from 43 to 118 kPa were reported. Based on these results the relationship between normal load and dynamic co-efficient of friction has been proposed. It was also observed that sample containing 80 wt.% of XNBR exhibits lesser volume loss than compared to other samples.     

机场跑道摩擦系数测试车标定装置研究

根据摩擦车力传感器标定需要,提出一种机场跑道摩擦车标定方法.分析了摩擦车和标定系统的标定原理和标定方法,选用PC104模块作为控制核心,设计控制系统完成标定实验,针对标定装置中测力传感器的非线性问题,应用基于分段最小二乘法拟合的数据处理方法.实验结果验证了算法的有效性.     

搅拌摩擦与氩弧焊铝合金接头疲劳性能的比较

建立了铝合金焊接接头的S-N曲线,对比分析了搅拌摩擦和氩弧焊两种工艺对其焊接接头疲劳性能的影响,结果表明:在载荷相同的条件下,铝合金搅拌磨擦焊接接头的疲劳性能优于氩弧焊接头,搅拌摩擦焊接头的疲劳寿命N=106次的疲劳强度为59-65 MPa,搅拌摩擦焊接接头具有比氩弧焊接头更为细小的晶粒和狭窄的焊接热影响区,阻碍了滑移带的形成和裂纹的扩展,从而提高了接头的疲劳性能,铝合金焊接接头的缺陷是主要的疲劳裂纹源.     

Numerical analysis for dynamic contact between high‐speed wheel and elastic beam with Coulomb friction

For numerical analysis of the dynamic contact between a high‐speed wheel and an elastic beam, the equation of motion of each body is time integrated by a simple ODE solution technique and frictional contact conditions are imposed by the augmented Lagrange multiplier method using the contact errors defined in this work. For the stability of the numerical solution, the velocity and acceleration contact conditions as well as the displacement contact condition are imposed with special consideration for the high‐velocity contact point moving on the deformed beam. Especially, it is shown that the Coriolis and centripetal accelerations of the contact point moving rapidly on the deformed beam play crucial roles for the stability of the solution. It is also shown that, for a wheel rolling on a beam with friction, the acceleration constraint in the tangential direction is important for the stability of the solution. Copyright © 2008 John Wiley & Sons, Ltd.     

温度对CPP薄膜润湿张力和摩擦系数变化的影响及其在生产过程检测的应用

简要介绍了CPP薄膜电晕处理原理和添加剂迁移机理，分析了温度对润湿张力和摩擦系数变化的影响，提出生产过程快速检测润湿张力和摩擦系数的方法。     

纸基摩擦材料的研究现状

简要评述了纸基摩擦材料组成、工艺和性能的研究进展.重点阐述了纸基摩擦材料的增强纤维、粘结剂树脂、摩擦性能调节剂和填料的研究现状,介绍了纸基摩擦材料多次漫渍、双层结构和孔隙控制制备技术,以及纸基摩擦材料的物理力学性能、摩擦磨损性能的研究方法.提出了纸基摩擦材料多元组合改性、性能协同研究、交互规律认识的热点课题.     

Effect of load changes on dynamic coefficient of friction of crystalline and amorphous materials

Journal of Materials Science Letters -     

AZ91及AZ91-Y合金复合干摩擦性能的对比

为了探究AZ91镁合金的复合干摩擦行为,以未淬火45钢为摩擦副,在不同载荷下(100,200,300 N),开展AZ91及Y含量为1.0%(质量分数)合金的复合干摩擦实验。采用OM,XRD,SEM等观察合金的磨损形貌并分析磨损机理。结果表明:增加法向载荷,两试样复合磨损率线性增加但摩擦因数却逐渐减小;Al 2Y硬质颗粒可细化晶粒、弱化相界面开裂倾向以提高AZ91-Y合金耐磨性。100,300 N法向载荷下,AZ91-Y合金主要磨损机制分别为磨粒磨损和剥离磨损,与基体(AZ91)一致,其磨损率分别降低了21.7%和5.9%。