利用静电纺丝技术制备了热塑性聚氨酯/多壁碳纳米管(TPU/MWNTs)复合纳米纤维,并通过平行板接收装置实现纤维的定向排布。测试了纤维压阻敏感性随MWNTs含量的变化规律,与浇注法制备的TPU/MWNTs膜的压阻敏感性进行对比分析,结果表明MWNTs含量仅为2.91%(质量分数)时,纤维就表现出了最佳的压阻特性(Gauge factor≈11.4),比同质量分数下膜的压阻特性(Gauge factor≈2.6)有较大的提高,同时在8%的拉伸应变内电阻的相对变化量与应变值维持良好的线性关系,线性度优于复合膜。

Electrospinning was applied to produce oriented nanofibers consisting of thermal-plastic polyurethane (TPU)and multi-walled nanotubes (MWNTs)composites.Comparison TPU/MWNTs films were made through casting technology.The relationship between relative changes in resistance versus tensile strain has been analyzed.The maximum gauge factor (≈1 1 .4)of fibers was reached when the mass fraction of MWNTs was 1.84%.At the same mass fraction,gauge factor of films was only 2.6.The piezoresistive response of fi-bers was linear within 8% of tensile strain which was better than that of TPU/MWNTs films.

摇摆条件下的气液两相流动受摇摆引起的附加惯性力的影响，致使其摩擦阻力特性发生改变。本工作在摇摆周期为8、12、16S和摇摆振幅为10°、15°、30°的条件下，对窄矩形通道（40mm×1．6mm）内空气一水两相流动的瞬态阻力特性进行了研究。结果表明：摇摆时瞬态摩阻系数的变化呈明显周期性；气相质量含气率越大，摩擦压降的波动幅度越大；摇摆周期越小，振幅越大，摩擦压降的波动幅度越大。给出1个用于计算摇摆条件下两相摩阻系数的关联式，92．5％的计算值的相对误差在±20％以内。

The additional force arising from rolling motion causes the change of two-phase flow resistance .The characteristics of air-water mixture flow resistance in narrow rectangular channel (40 mm × 1.6 mm) in rolling motions were experimentally studied with the rolling periods of 8 s ,12 s ,16 s and the angles of 10° ,15° ,30° ,respectively . T he experimental results show that the transient frictional factor changes periodically . The larger the mass quality and the maximum rolling angle and the smaller the rolling period ,the larger the fluctuation amplitude of frictional pressure drop .A new correc-tion for predicting the transient frictional factor of two-phase flow in rolling motion is proposed with a good accuracy .

采用可控温不锈钢环道对集输管道常见浓度范围内含聚丙烯酰胺水溶液的流动特性进行了室内实验研究。研究结果表明：温度对聚丙烯酰胺溶液压降梯度的影响存在一个临界浓度，在临界浓度后，聚丙烯酰胺溶液的压降梯度随温度的升高逐渐减小，在临界浓度前会出现随温度升高压降梯度增大的现象；压降梯度随聚丙烯酰胺浓度的升高先减小后增大，随流速的降低、温度的升高聚丙烯酰胺溶液的最低压降点后移。减阻率随流速的升高逐渐增大；随流速的降低、温度的升高最高减阻率点后移。聚丙烯酰胺溶液表现出明显的剪切稀释性。通过对实验数据的分析得到了聚丙烯酰胺溶液的增黏特性占主要地位时其混合黏度符合的方程组。

This passage studies the flow characteristics of polyacrylamide (PAM) solution in a pipeline at the common concentration range of gathering lines. The experiments were carried out in a 25.4 mm nominal bore horizontal double-wall pipeline which is made up of stainless-steel and can be temperature controlled by a water bath. The results show that:there is a critical concentration point existing on the influence of temperature on pressure drop gradient,after the concentration point the pressure drop gradient decreases with the rise of temperature,before the critical concentration point pressure drop gradient increasing with the rise of temperature would occur,the critical concentration point is related to velocity;the pressure drop gradient first decreases then increases with the rise of PAM concentration,the minimum pressure drop point would move backwards with the decrease of velocity and rise of temperature. The drug reduction efficiency increases with the rise of temperature

针对常用Hopkinson杆动态校准系统进行高安装谐振频率高g值加速度计动态校准时激励脉宽不能满足要求,且幅频特性曲线工作频带内不平直的问题,本文提出了微小型Hopkinson杆的动态校准系统,该系统采用微小尺寸精密校准杆,并对传感器安装结构进行了改进,且实验证明该系统对高安装谐振频率的高g值压阻加速度计和BK 8309高g值压电加速度计进行动态校准得到的幅频特性曲线较为理想。

In view of the commonly dynamic calibration system used Hopkinson bar for high resonant frequency and high-g accelerometer dynamic calibration problem of excitation pulse width can not meet the requirements,and the amplitude frequency characteristic curve in working frequency band is not straight. So put forward the micro small Hopkinson bar dynamic calibration system,the system adopts the tiny size precision calibration bar and the sensor installation structure is improved. The experiment with high-g value piezoresistive and B&K 8309 piezoelectric accelerometer proved that the system of dynamic calibration of amplitude frequency characteristic curve is more desirable.

为了揭示钻井液在钻柱内的流动特性,采用数值模拟方法建立了涡动钻柱内赫巴流体的流动模型,结合流体力学相关理论,对比分析了速度剖面与表观黏度剖面,研究了钻柱自转速度、公转速度、轴向流速及流体密度等参数的变化对钻柱内流场的影响,得到了各参数对涡动钻柱内摩阻压耗的影响规律。研究表明,公转速度正向增大或反向减小时摩阻压耗都有减小的趋势,自转速度增大时摩阻压耗有增大的趋势。由此可见,考虑钻柱涡动的摩阻压耗变化规律,可使涡动钻柱内钻井液的描述更接近于实际钻井工况,有助于钻井液循环系统的优化。

In order to reveal flow behavior of drilling fluid in drill string ,numerical simulation method is adopted to establish a mathematical flow model about Herschel-Bulkely fluid in w hirl drill string .Com-bined with the theory of fluid mechanics ,the model was used to analyze and compare velocity and apparent viscosity profiles .The effects of variation in drill string rotation velocity ,revolution velocity ,axial flow ve-locity and fluid density on flow field were examined ,the regularity of effect with each parameter on friction pressure loss in whirl drill string was found .The study shows that friction pressure loss was reduced with the positive increase or reverse decrease of revolution speed ,but friction pressure loss increased with the in-crease of rotation speed .T herefore ,w hen taking friction pressure loss into account ,the description of drill-ing fluid flow in w hirl drill string will be much closer to actual drilling condition ,facilitating the optimiza-tion of drilling c