Evaluation of frequency dependence of adiabatic compressibility and transition of mechanical behaviors for traction oils

考虑到研究计划，本文的研究成果概要如下：(1)利用钻石顶压腔建立了高达3 GPa150ﾟC的布里渊光散射测量技术。找出了高压密度的频散关系，推测在GHz频率范围内，原油在室温下表现为弹塑性，随温度升高向粘弹性和粘性转变。(2)在GHz频率附近，用布里渊散射法计算了声速的色散。随着频率的增加，低粘度液体的频率增加了几个百分点，10mPAS液体增加了10%，1PAS液体增加了几个百分点。同样，在高压下进行了分散实验，获得了高达5 Gpa的合成润滑剂的物理性能。随着压力的增加，色散立即消失，并提出了加载和卸载之间弹性模量值滞后的可能性。(3)利用超声仪测得的声速为1500m/S，与油的种类和频率无关。建立了高温测量系统和程序，并对高压超声仪的设计进行了初步实验。(4)布里渊散射结果(GHz)和超声结果(MHz)的绝热压缩系数相差最大40%。通过对Ohno等人提出的润滑剂的流变性进行外推，得到了高达2 Gpa的力学行为相变，高压牵引试验结果似乎处于弹塑性区，速度的提高与粘度的增加具有相似的影响。(5)进行了一种新的尝试，即用DAC分析多孔固体材料在超高压下的摩擦力，这类似于考虑自由体积的润滑剂。

Abstracts of this research results are outlined as follows considering research schedule : (1)Brillouin light scattering measurement technique up to 3 GPa and 150ﾟC was established employing a diamond-anvil cell (DAC). Frequency dispersion of high-presuure density was found out, and it was deduced that, in GHz frequency region, oils behave like elasticplastic at room temperature and transit to viscoelastic and viscous feature with elevating temperature. (2)Around GHz frequency, the dispersion of sound velocity was evaluated by Brillouin scattering. With twice increase of frequency, a few % increase for low viscosity liquids was observed, and 10 % for 10 mPas liquids, and a few % for 1 Pas liquids. Similarly, Dispersion experiment under high pressure was made and physical properties for synthetic lubricants up to 5 GPa were obtained. Dispersion was resulted to disappear immediately with pressure and the possibility of hysteresis of elastic modulus between loading and unloading was proposed. (3)Employing ultra-sonic apparatus, MHz sound velocity measurements gave the value of 1500 m/s independent of the kind of oils and frequency. High temperature measurement system and procedure was established and the preliminary experiment for high pressure ultra-sonic apparatus design was made. (4)The difference of adiabatic compressibility between Brillouin scattering results (GHz) and ultra-sonic results (MHz) was turned out to be at most 40 %. Phase transition of mechanical behavior was estimated up to 2 GPa by extrapolating rheological regime of lubricants proposed by Ohno et al.and high pressure traction test results seemed to be in the elasticplastic region and velocity increase has similar effect as viscosity increase. (5)A new attempt was made, that is, the analysis of frictional force for porous solid materials under very high pressure using DAC,which is similar to lubricants including free volume.