通过神经网络加速实现大型黏弹性计算

认识重复地震周期活动的影响,其最大的挑战之一是大尺度的黏弹性地震周期模型的计算成本。对于计算密集型黏弹性代码,须在数以千计的时间和位置点上进行评估。因此,研究趋向于采用几个固定的流变结构和模型几何结构,考查所预测的大震后短时间(小于10年)内给定深度处不同时间的形变。训练一个深层神经网络来学习黏弹性解在任意时间、位置和大范围流变结构计算效率的表示,可快速且可靠地完成计算,并具有较高时空分辨率。结果表明,该机器学习方法可以将黏弹性计算速度提高50 000%以上。这种加速量级将使得在更大的模型参数范围内、在比以前更大的时空尺度上和数千个地震周期内,模拟几何结构复杂的断层成为可能。     

ROCESSES OF EPHEMERAL GULLY EROSION

IINTRoDUCTIONEphemeralgulliesaresmallerosionalchannelsonagriculturalIandscapescausedbytheconcentrationofoverlandflowtypicallybetweentwoopposingslopes(ahollow),oftenformedduringasingIerainfaIlevent.Sincethescouredsoilvolumeisnotverylargewithinthesegullies,farmerscaneasilyrefillthem.Ingeneral,ephemeralgulliescanreappearatornearthesamelocationonayearlybasisbecausethesurfacetopograPhyofthefielddoesnotchangeappreciably.Mostephemeralgulliesoccuroncultivatedfieldswithhighlyerodiblesoils,withlit…     

SEDIMENT TRANSPORT PROCESSES IN AGRICULTURAL WATERSHEDS

lINTR0DUCTI0NTheerosion,transportanddep0siti0nofsedimentinawatershedarepallofthenaturalsystemofwatershedprocesses.InanundistUrbedwatershed,s0ilsinuplandareasaregraduallyeroded,transportCdforsomedistanceandeventuallydepositedatlowereIevations.WhenwatershedsaredistUrbedbyhumanactivitiessuchasclearingofvegetation,urbaniZati0n,orotherchangesthataffectthelandscaPe,unstablechannelswithlocallyhighratesoferosion,transport,0rdepositionofsedimentoftenaretheresult.Theimpact0fer0sionisespeciallyhigh…     

对MG两篇文章的答复之二

简单查看一下ＭＧ针对１９８７－１９８９年这一时间段的图表可以发现以下两个事实；（１）回想一下预报只有在所报地震震级Ｍｐｒｅｄ≥５．０时才发布，真实的ＶＡＮ预报的成功率为７９％，在只将的地震当做预报成功时，成功率为４５％。（２）ＶＡＮ的预警率对于震级大时明显上升，如对于ＭＥＧ≥５．０，５．３，５．５，５．８，预警率分别为２２％，３６％，５．０％，６０％。这些事实与ＭＧ所谓的“ＶＡＧ”预报结果可归因于     

A STUDY ON SEDIMENT PROBLEMS IN THE GONGZUI RESERVOIR

IINTRODUCTIONTheannualaverageruff-offinthewatershedoftheGongzuiReservoiris50billioncubicmeterswithanaveragesedimentloadof34.7milliontonsperyear.Finesedimentwithd,,=0'055mmcompose97%oftheiota]sedimentload.Theannualcoarsegravelpericleswithd,,=58.5mmisaboutonemilliontons.TheendofbackWateris38kmawayfromthedam.Thereservoirwasoriginallydesignedtoatotalstoragecapacityof374millioncubicmeters,inwhich102millioncubicmetersisregulationstoragecapacityand243millioncubicmetersis'dead'storagecapacityfo…     

动态裂纹稳定性的分子动力学研究

为了估算几个物理因素对动态裂纹稳定性的影响,进行了一系列分子动力学模拟。这些是由各种实验潜势模拟得到的晶体结构和原子间的相互作用。对于低温下脆性裂纹的扩展。我们发现稳态裂纹 的速度限制在一个易于牟数值区间内。当增另过载并且远远超过ＫＩＣ时,裂纹以稳态速度扩展并迅速达到终止速度,即约耿０．４个瑞利波速度,终止速度的幅值可能与原子间相互作用的非线性有关。进一步增加过载并未显著地改变稳态速度,却明显地增     

金顶超大型铅锌矿床氦、氩同位素地球化学

对金顶超大型铅 锌矿床成矿阶段形成的黄铁矿中流体包裹体的氦、氩同位素的研究结果表明 ,成矿流体的40 Ar/ 3 6Ar≈ 30 1 .7～ 385 .7,3 He/ 4 He≈ 0 .0 3～ 0 .0 6Ra,成矿流体属于饱和空气的表生水 .在此基础上 ,对氦、氩、硫、铅同位素耦合关系的研究进一步确定出该矿床成矿流体的形成演化过程为 :饱和空气的大气成因地下水下渗增温→通过水 岩作用从盆地地层中获取硫和氯以及放射成因的氦和氩→浸取盆地底部幔源火成岩中的铅和锌→含矿流体回返上升成矿 .由于这一过程的结果 ,而使成矿流体留下了地壳放射成因氦、(叠加有部分放射成因40 Ar的 )大气氩、地壳成因硫和幔源铅的同位素组成特征 .     

Experimental Studies on Elasticities of Forsterite-Enstatite Composites:Towards an Understanding of the Rules of Mixture

Which rule of mixture is the best for predicting the overall elastic properties of polyphase rocks based on the elastic properties and volume fractions of their constituents? In order to address this question, we sintered forsterite-enstatite polycrystalline aggregates with a varied forsterite volume fraction (0, 0.2, 0.4, 0.5, 0.6, 0.8, and 1.0). Elastic properties (shear, bulk, and Young's moduli) of these synthesized composites were measured as a function of pressure up to 3.0 GPa in a liquid-medium piston-cylinder apparatus using a high-precision ultrasonic interferometric technique. The experimental data can be much better described by the shear-lag model than by the commonly used simple models such as Voigt, Ruess and Hill averages, Hashin-Shtrikman bounds, Ravichandran bounds, Halpin-Tsai equations, and Paul's calculations. We attributed this to the fact that the elastic interaction and stress transfer between phases are neglected in all the models except for the shear-lag model. In particular, t