PAM/GO复合材料制备及驱油性能研究

利用改进的Hummers法制备氧化石墨烯(Graphene oxide,GO),并利用原位聚合法引入丙烯酰胺(AM),制备PAM/GO复合材料。采用X射线衍射(XRD)、傅里叶红外光谱(FTIR)、激光粒度分析和驱油实验等分析方法对PAM/GO复合材料的官能团和驱油性能进行了研究。X射线衍射(XRD)、傅里叶红外光谱(FTIR)实验结果表明,PAM/GO的谱图中,在2θ=9.4°的氧化石墨的特征峰消失,在2θ=23°出现一个宽的衍射峰,说明PAM/GO为无定形结构,也说明氧化石墨与PAM兼容性良好,没有发生明显的团聚。傅里叶变换红外光谱分析表明,PAM/GO红外谱图中具有很明显的丙烯酰胺特征峰,说明丙烯酰胺成功引入到氧化石墨烯中。激光粒度分析结果表明,石墨烯复合材料的平均粒径范围在0.19~1.45μm。界面张力分析表明,0.3%浓度的石墨烯材料降低油水界面张力的能力较好,与注入水相比,能将油水界面张力从101降低到100数量级左右。PAM/GO复合材料应用于低渗透岩心的动态驱替实验表明,0.3%浓度的石墨烯复合材料对低渗透油藏提高采收率在10%左右,且驱替压力变化平稳,不会对地层造成堵塞伤害。     

纳米银/聚合物复合材料的原位法制备技术综述

纳米银/聚合物复合材料结合了纳米银优异的物理化学性能和聚合物的易加工和成膜性的特点,被广泛应用于抗菌、催化和光电等领域。原位法具有工艺简单、成本低、可形成单分散的纳米粒子等优点,被广泛用于制备纳米银/聚合物复合材料。主要综述了纳米银/聚合物复合材料的原位制备方法,主要包括原位生成法、原位聚合法、双原位合成法,并提出了纳米银/聚合物复合材料的发展方向。     

High strength and ductility of 34CrNiMo6 steel produced by laser solid forming

Because of the excellent mechanical properties of 34CrNiMo6 steel, it is widely used in high-value components. Many conventional approaches to strengthening-steels typically involve the loss of useful ductility. In this study, 34CrNiMo6 Steel having high strength and ductility is produced by laser solid forming (LSF) with a quenching-tempering (QT) treatment. Tempering of bainite is mainly by solid phase transformation in the previous LSF layers during the LSF process. The stable microstructure of LSF consists of ferrite and fine carbides. The microstructure transfers to tempered sorbite after heat-treatment. The tensile properties of the LSF steel meet those of the wrought standard. The UTS and elongation of LSF sample at 858 MPa, 19.2%, respectively, are greater than those of the wrought. The QT treatment enhanced the ultimate tensile strength and yield strength of the LSF sample. The ultimate tensile strength, yield strength, reduction in area, and elongation of the LSF+QT sample at 980 MPa, 916 MPa, 58.9%, and 13.9%, respectively, are greater than those of the wrought standard. The yield strength of the LSF+QT sample is approximately 1.27 times that of the wrought. The LSF samples failed in a ductile fracture mode, while the LSF+QT samples showed mixed-mode failure. The defects have only a small effect on the tensile properties owing to the excellent ductility of the LSF sample.     

Improving the spatio-temporal distribution of surface solar radiation data by merging ground and satellite measurements

Appropriate information on solar resources is very important for a variety of technological areas, such as: agriculture, meteorology, forestry engineering, water resources and in particular in the designing and sizing of solar energy systems. However, the availability of observed solar radiation measurements has proven to be spatially and temporally inadequate for many applications. In this paper we propose to merge the global solar radiation measurements from the Royal Meteorological Institute of Belgium solar measurements network with the operationally derived surface incoming global short-wave radiation products from Meteosat Second Generation satellites imageries to improve the spatio-temporal resolution of the surface global solar radiation data over Belgium. We evaluate several merging methods with various degrees of complexity (from mean field bias correction to geostatistical merging techniques) together with interpolated ground measurements and satellite-derived values only. The performance of the different methods is assessed by leave-one-out cross-validation.     

水泵试验台流量原位标定系统研制

为保证水泵试验台精度和试验稳定性,除了选择高精度的测流设备外,还应有高精度的流量原位标定装置。提出了称重-容积法原位标定方法,在水泵试验台上实现了流量计的正、反向原位标定。根据系统设计目标,对供水加力水泵、称重桶、水池、气动换向器和标准金属量器分别进行了选型和计算。依据测量不确定度理论,标定系统不确定度主要由标准量器、计时器、换向器和容积法标定传感器装置等不确定度组成,计算了称重桶容积法、换向器和整个系统的不确定度。经试验和计算,系统扩展不确定度为0.136%,系统流量稳定度为0.0212%。计算和压力脉动测试结果表明采用溢流供水池和变频调速加力泵相结合的方法可保证系统标定时压力稳定。称重-容积法原位标定方法将称重法和容积法有效的结合起来,在水泵试验台中成功地得到了应用。该方法达到了既保证精度又降低造价的目的,具有较好的推广应用前景。     

某围垦工程原位监测施工和分析

通过某围垦工程原位监测施工实施,阐述了原位监测的目的和意义,并对原位监测成果进行分析,得到监测的有效数据,从而指导下一步的施工,确保地基稳定、沉降均匀。     

Train-induced vibration on elevated railway station

Results of in-situ vibration measurement carried out at Tianjin West Elevated Railway Station which has the trains running on the station structure were reported. The main excitation source is the train passing through the station. Vibration measurements were recorded in the vertical direction of the supporting track beam, the platform and the steel truss beam of the waiting hall, as well as in the vertical, longitudinal and transverse directions of the roof arch base of the station. Acceleration time responses were obtained. The maximum value, vibration level and one-third octave band RMS spectra of the measured accelerations were studied. The propagation of vibration in different structural floors was discussed. The influence of train speed, distance to the vibration source and the type of train on the structural vibration were analyzed. Results show that the vibration level increases with the train speed, while it attenuates with the distance to the track. Furthermore, the vibration responses of different structural floors were compared, and it is noted that the vertical vibration of the bottom slab of the platform is most severe and the transverse vibration of the roof arch base is the smallest. The results provide reference on the vibration characteristics and vibration energy distribution of this type of ＂Train on building frame＂ system used as an elevated railway station.     

SEM in-situ investigation on fatigue cracking behavior of P/M Rene95 alloy with surface inclusions

The low-cycle fatigue behavior of powder metallurgy Rene95 alloy containing surface inclusions was investigated by in-situ observation with scanning electron microscopy （SEM）. The process of fatigue crack initiation and early stage of propagation behavior indicates that fatigue crack mainly occurs at the interface between the inclusion and the matrix. The effect of inclusion on the fatigue crack initiation and the early stage of crack growth was very obvious. The fatigue crack growth path in the matrix is similar to the shape of inclusion made on the basis of fatigue fracture image analysis. The empiric relation between the surface and inside crack growth length, near a surface inclusion, can be expressed. Therefore, the fatigue crack growth rate or life of P/M Rene95 alloy including the inclusions can be evaluated on the basis of the measurable surface crack length parameter. In addition, the effect of two inclusions on the fatigue crack initiation behavior was investigated by the in-situ observation with SEM.     

Measurement and study of the distributing law of in-situ stresses in rock mass at great depth

To solve the technical cruxes of the conventional system in deep rock mass, an automatic testing system for hydraulic fracturing that includes a single tube for hydraulic loop, a pressure-relief valve, central-tubeless packers, and a multichannel real-time data acquisition system was used for in-situ stresses measurement at great depths （over 1000 m） in a coalfield in Juye of Northern China. The values and orientations of horizontal principal stresses were determined by the new system. The virgin stress field and its distributing law were decided by the linear regression from the logged 37 points in seven boreholes. Besides, the typical boreholes arranged in both the adjacent zone and far away zone of the faults were analyzed, respectively. The results show that a stress concentration phenomenon and a deflection in the orientation of the maximal horizontal stress exist in the adjacent zone of the faults, which further provides theoretical basis for design and optimization of mining.     

Oxidation kinetics and high temperature in-situ observation of the oxidation behaviour of NbSi_2 at 1023 K

Pest oxidation has been known for a long time in refractory transition-metal disilicides such as NbSi2 and MoSi2[1―4]. However, the origin of pesting reaction of these materials is still under debate. Although the pesting phenomenon in NbSi2 has been reported in several works[5―7], a direct study of the mechanism is scarce at the moment. Compared to NbSi2, pesting in MoSi2 has received relatively extensive attention. Mckamey et al.[8] showed fragmentation near 773K occurred easily in as…