摘要：The relationship between engine mechanics and thermo-dynamics has been investigated by means of numerical *** inherent mismatching between the mechanical behaviors and the thermodynamic process in internal combustion engine is identified,which is believed to be one of the important limiting factors of energy efficiency for conventional engines available in the current *** approach for engine efficiency improvement through optimal matching between mechanics and thermodynamics(OMBMT)is *** ideal matching model is defined and the conflicts due to the constraints among the mapping strokes in a 4-stroke engine are analyzed.A novel mechanical model is built for approaching optimal matching among all 4 individual strokes in a 4-stroke spark-ignition engine,which is composed of non-circular gears(NCG)and integrated with conventional slider crank engine *** means of digital mechanical model and numerical simulation,the matching gains among all 4 strokes are defined and calculated for quantifying the NCG engine efficiency improvement by comparing with a baseline *** potentials with the OMBMT implemented and the enhancements made by NCG mechanism for engines in terms of overall engine efficiency are *** on the results achieved,it is recommended that the feasibility studies and the experimental validations should be conducted to verify the engine matching concept and effectiveness of the NCG mechanism engine model proposed,and the engine performance and NCG design parameters should be further optimized.

摘要：In terms of lightweight electromagnetic interference(EMI)shielding structural materials,Mg matrix materials have proven to be the best,due to their exciting properties(*** density,high specific strength,good electrical conductivity and excellent EMI shielding properties)and their wide range of applications in lightweighting in electronics,automotive and aerospace *** processing,such as alloying,heat treatment,plastic deformation and composite processing,Mg matrix materials can be obtained with tailorable properties which can play a key role in designing materials for EMI *** work introduces an overview of the research on the EMI shielding properties of Mg matrix materials as well as their EMI shielding mechanisms over the past few decades,focused on the influence of alloying,heat treatment,plastic deformation and composite processing for the EMI shielding properties of Mg matrix *** the end,conclusions and future perspectives are provided.

摘要：Ski tourism is extremely sensitive to climate change and is also heavily affected by socioeconomic *** some ski areas arestill profitable under current climate and socioeconomic conditions,they will become difficult to operate in the face of rising winter temper-atures,which will result in further economic losses,resource waste and environmental *** study projects variability in the suitability ofski area development across China in the coming *** suitability under three representative concentration pathway emission sce-narios(RCP2.6,RCP4.5 and RCP8.5),socioeconomic suitability under four shared socioeconomic pathways(SSP1,SSP2,SSP3,and SSP5)andintegrated suitability under four climatic-socioeconomic scenarios(RCP2.6-SSP1,RCP4.5-SSP2,RCP8.5-SSP3,and RCP8.5-SSP5)are ***,the suitability of 731 existing ski areas in China is *** results show a substantial decline in integrated suitabilityfor most regions of China except for some very cold areas,where higher air temperatures will make visitors feel more comfortable and therelatively poor socioeconomic conditions will improve in the 2030s,2050s and *** average higher integrated suitability area(integratedsuitability values greater than 0.5)under four climatic-socioeconomic scenarios decreases from the current 29.9%e14.4%,5.0%and 4.5%bythe 2030s,2050s and 2090s,*** RCP2.6-SSP1,the higher integrated suitability area is projected to decrease from the current28.0%e5.2%by the 2050s and then increase to 5.3%by the *** RCP4.5-SSP2,RCP8.5-SSP3,and RCP8.5-SSP5,the higher inte-grated suitability area is projected to continuously decrease from 30.3%,30.6%and 30.6%in the 2010s to 4.1%,4.4%and 4.4%in the 2090s,*** the 2090s,41,138 and 277 existing ski areas are projected to be closed under RCP2.6-SSP1,RCP4.5-SSP2,and RCP8.5-SSP3/RCP8.5-SSP5,*** is clear that emission pathways and climate change adaptation and mitigation