ANALYSIS ON INFILTRATIVE CHARACTERISTICS OF DEFORMABLE POROUS MATAL RUBBER MATERIAL AND PARAMATERS IDENTIFICATION

The effect of deformation of porous material on infiltrative performance is investigated. Based on Darcy theory and Boit principle, the Reynolds equation and mathematical expression of deformable metal rubber （MR） material under laminar flow are obtained according to the change of porosity of metal rubber. It is shown that the throttle of MR material is dependent on its porosity and diameter of metal wires. It will be of great value for the application of MR in throttle field.

Thermal properties of diamond/Al composites by pressure infiltration:comparison between methods of coating Ti onto diamond surfaces and adding Si into Al matrix

This study was pertained to the effects of Ti coating on diamond surfaces and Si addition into Al matrix on the thermal conductivity（TC） and the coefficient of thermal expansion（CTE） of diamond/Al composites by pressure infiltration.The fracture surfaces,interface microstructures by metal electro-etching and interfacial thermal conductance of the composites prepared by two methods were compared.The results reveal that Ti coating on diamond surfaces and only12.2 wt% Si addition into Al matrix could both improve the interfacial bonding and increase the TCs of the composites.But the Ti coating layer introduces more interfacial thermal barrier at the diamond/Al interface compared to adding 12.2 wt% Si into Al matrix.The diamond/Al composite with 12.2 wt% Si addition exhibits maximum TC of 534 W·m^-1·K^-1and a very low CTE of 8.9×10^-6K^-1,while the coating Ti-diamond/Al composite has a TC of 514 W·m^-1·K^-1 and a CTE of 11.0×10^-6K^-1.

基于优化基流分割方法的基流时空变化及其驱动因素评估

Baseflow is an important component of river or streamflow.It plays a vital role in water utilization and management.An improved Eckhardt recursive digital filter(IERDF)is proposed in this study.The key filter parameter and maximum baseflow index(BFImax)were estimated using the minimum smoothing method to improve baseflow estimation accuracy.The generally considered BFImax of 0.80,0.50 and 0.25 according to the drainage basin’s predominant geological characteristics often leads to significant errors in the regions that have complex subsurface and hydrologic conditions.The IERDF improved baseflow estimation accuracy by avoiding arbitrary parameter values.The proposed method was applied for baseflow separation in the upstream of Yitong River,a tributary of the Second Songhua River,and its performance was evaluated by comparing the results obtained using isotope-tracer data.The performance of IERDF was also compared with nine baseflow separation techniques belonging to filter,BFI and HYSEP methods.The IERDF was also applied for baseflow separation and calculation of rainfall infiltration recharge coefficient at different locations along the Second Songhua River’s mainstream for the period 2000–2016.The results showed that the minimum smoothing method significantly improved BFImax estimation accuracy.The baseflow process line obtained using IEDRF method was consistent with that obtained using isotope 18 O.The IERDF estimated baseflow also showed stability and reliability when applied in the mainstream of the Second Songhua River.The BFI alone in the river showed an increase from the upstream to the downstream.The proportion of baseflow to total flow showed a decrease with time.The intra-annual variability of BFI was different at different locations of the river due to varying climatic conditions and subsurface characteristics.The highest BFI was observed at the middle reaches of the river in summer due to a water surplus from power generation.The research provided valuable information on baseflow characteristics and runoff mode determination,which can be used for water resources assessment and optimization of economic activity distribution in the region.