Preliminary analysis for the roles of crustal low-velocity and high-conductivity body in process of strong earthquake preparation

In this paper, the roles of low velocity and high conductivity body inside the crust in the process of strong earth quake preparation are approached by using theoretical analysis method based on the comprehensive researches on the fine structure of strong seismic source in the North China. The following results are obtained. The low-velocity and high-conductivity body plays the promoting role for the action of deep-seated structure in the medium stage of earthquake preparation, except that its existence is advantageous to the stress concentrating in the overlying brittle layer during the process of earthquake preparation. And it plays the triggering role for the occurrence of strong earthquake in the later stage of earthquake preparation.

Experimental investigation of rotary sinking electrochemical discharge milling with high-conductivity salt solution and non-pulsed direct current

Electrochemical milling is a modified technique of traditional electrochemical machining(ECM)that can be used to manufacture some helicopter transmission system parts.The use of rotary tools and an inner-jet electrolyte supply pattern can greatly improve the material removal rate(MRR)in a single pass.However,the feed speed is generally limited to minimize the tool wear.To increase the MRR,electrical discharge machining(EDM)is introduced into the electrochemical milling process.The tool rotation is employed to interrupt the discharge and the high-conductivity salt solution and non-pulsed direct current power supply are also adopted to increase ECM,eventually,a new machining method is proposed,which can be called rotary sinking electrochemical discharge milling(RSECD milling).The mechanism of it is explored in this study by analyzing the machined current,MRR,surface morphology,and tool wear at different applied voltages and feed speeds.Besides,the RSECD milling using the tool with a larger diameter is also conducted to further verify the effectiveness.In particular,the MRR can be increased by 742.5%when using the tool with a diameter of 20 mm at the applied voltage of 20 V.

Electrical Structure and Fault Features of Crust and Upper Mantle beneath the Western Margin of the Qinghai-Tibet Plateau:Evidence from the Magnetotelluric Survey along Zhada-Quanshui Lake Profile

The magnetotelluric （MT） survey along the Zhada （札达）-Quanshui （泉水） Lake profile on the western margin of the Qinghai （青海）-Tibet plateau shows that the study area is divided into three tectonic provinces by the Yalung Tsangpo and Bangong （班公）-Nujiang （怒江） sutures. From south to north these are the Himalayan terrane, Gangdise terrane, and Qiangtang （羌塘） terrane. For the study area, there are widespread high-conductivity layers in the mid and lower crust, the top layers of which fluctuate intensively. The high-conductivity layer within the Gangdise terrane is deeper than those within the Qiangtang terrane and the Himalaya terrane, and the deepest high-conductivity layer is to the south of the Bangong-Nujiang suture. The top surface of the high-conductivity layer in the south of the Bangong-Nujiang suture is about 20 km lower than that in the north of it. The high-conductivity layer within the Gangdise terrane dips toward north and there are two high-conductivity layers within the crust of the southern Qiangtang terrane. In the upper crust along the profile, there are groups of lateral electrical gradient zones or distortion zones of different scales and occurrence indicating the distribution of faults and sutures along the profile. According to the electrical structure, the structural characteristics and space distribution of the Yalung Tsangpo suture, Bangong.Nujiang suture, and the major faults of Longmucuo （龙木错） and Geerzangbu are inferred.

Earthquake-controlling Processes of Detachment Zones in Eastern North China

The basin-and-range area in eastern North China is known for frequent occurrence of earthquakes, their great magnitudes and heavy losses thereby incurred. Seismic studies in the past usually emphasized the intersections, inflexions and branches of the faults. However, the intensities of many great earthquakes in this area do not show linear distribution, and the epicenters are horizontally dispersed at certain depths instead of along the strike of faults. Based on the sub-mantle plume studies made by authors in the past decade, it is thought that there exists an uplifted sub-mantle plume under the fault depression area in North China. The uplifting and intrusion of mantle materials caused the upper crust to be faulted, while low-velocity and high-velocity layers are alternatively distributed in the middle crust under the influence of the mantle and the lower crust. The middle and lower crust materials were detached from the top of the sub-mantle plume to the surroundings while the sub-mantle plume materials were detached outward. When the detached middle and lower crust come to the boundary of fault basins in the upper crust, they will be obstructed by the orogenic zone and the detachment will go slower. The shearing between them will cause the stress to accumulate and release alternatively, so that earthquakes occurred frequently in the areas of sub-mantle plume and its surroundings.

Study on the Electrical Conductivity of 0.025 mol NaCl Solution at 0.25-3.75 GPa and 20-370℃

The electrical conductance of 0.025 mol NaCl solution was measured at0.25-3.75 GPa and 20-370℃. As shown by the results, the conductance increases with temper-ature, and there is a liner relation between the reciprocal of temperature and the logarithm ofthe conductance but their slopes are different at different pressures. The relations between theconductance and pressure is rather complex and there are some discontinuities: in the range of2.25-3.75 GPa, the conductance increases with the pressure; in the range of 1.25-2.0 GPa, theconductance is not related to the pressure; and at a pressure of 0.75 GPa, the conductance ishigher than that at the pressures nearby. This reflects that the NaCl solution has rather differentproperties of electronic chemistry at various pressures, and probably is an important cause forthe existence of the layers with high electrical conductance and low velocity in the Earth's crustand mantle.

Ultra-high conductive 3D aluminum photonic crystal as sulfur immobilizer for high-performance lithium-sulfur batteries

The practical application of lithium-sulfur (Li-S) batteries is hampered by the insulative nature of sulfur, sluggish electrochemical kinetics, and large volume variation, which result in capacity-fading at a large current density and poor cycling stability. Herein, a three-dimensional (3D) aluminum photonic crystal encapsulating sulfur (APC@S) composite as a binder-free cathode for Li-S battery is reported. The 3D APC@S cathode can deliver a fantastic capacity of 1,517.8 mAh·g^(−1) at 0.5 C, and retains 712.7 mAh·g^(−1) after 1,500 cycles at 2 C with a decay rate of 0.02% per cycle. Even at a high rate of 5 C, the reversible capacity can still maintain at 680.7 mAh·g^(−1) after 1,000 cycles with a capacity retention of 74.8%. Furthermore, the assembled soft-packaged Li-S battery also exhibits high reversible capacity and stable cycling performance. The excellent electrochemical performance is attributed to the 3D hierarchical and continuously porous structure and high conductive aluminum-wall, which can effectively trap polysulfides, confine the volume expansion on cycling, and accelerate electron/ion transfer. It is expected that this high conductive metal cathode has a great future for the application of energy storage devices.