Numerical simulation and experimental verification of plasma jet development in gas gap switch

Plasma jet triggered gas gap switch has obvious advantages in fast control switch.The development of the plasma in the ambient medium is the key factor affecting the triggering conduction of the gas switch.However,the plasma jet process and its characteristic parameters are complicated and the existing test methods cannot fully characterize its development laws.In this work,a two-dimensional transient fluid calculation model of the plasma jet process of the gas gap switch is established based on the renormalization-group k-εturbulence equation.The results show that the characteristic parameters and morphological evolution of the plasma jet are basically consistent with the experimental results,which verifies the accuracy of the simulation model calculation.The plasma jet is a long strip with an initial velocity of 1.0 km·s-1and develops in both axial and radial directions.The jet velocity fluctuates significantly with axial height.As the plasma jet enters the main gap,the pressure inside the trigger cavity drops by80%,resulting in a rapid drop in the jet velocity.When the plasma jet head interacts with the atmosphere,the two-phase fluid compresses each other,generating a forward-propelled pressure wave.The plasma jet heads flow at high velocity,a negative pressure zone is formed in the middle part of the jet,and the pressure peak decreases gradually with height.As the value of the inlet pressure increases,the characteristic parameters of the plasma jet increase.The entrainment phenomenon is evident,which leads to an increase in the pressure imbalance of the atmospheric gas medium,leading to a significant Coanda effect.Compared with air,the characteristic parameters of a plasma jet in SF6are lower,and the morphological evolution is significantly suppressed.The results of this study can provide some insight into the mechanism of action of the switch jet plasma development process.

Dealloying-induced dual-scale nanoporous indium-antimony anode for sodium/potassium ion batteries

InSb alloy is a promising candidate for sodium/potassium ion batteries(SIBs/PIBs)but challenged with achieving high performance by dramatic volumetric changes.Herein,nanoporous(np)-InSb with dualscale phases(cubic/hexagonal(C/H)-InSb)was fabricated by chemical dealloying of ternary Mg-In-Sb precursor.Operando X-ray diffraction(XRD)and ex-situ characterizations well rationalize the dealloying/alloying mechanisms and the formation of dual-scale microstructures/phases.As an anode for SIB/PIBs,the np-InSb electrode exhibits superior reversible capacities and lifespan compared with the monometallic porous(p)-In electrode,stemming from the dealloying-induced dual-scale nanoporous architecture and alloying strategy with proper composition.The operando XRD results demonstrate that the(de)sodiated mechanism of the np-InSb electrode involves a two-step(de)alloying process,while the(de)potassiated mechanism is associated with a full electrochemically-driven amorphization upon cycling.Additionally,the gas evolution during the(dis)charge process was monitored by on-line mass spectrometry.

Two Retroviruses Packaged in One Cell Line can Combined Inhibit the Replication of HIV-1 in TZM-bl Cells

The cellular protein tetherin tethers the HIV-1 viral particles on the cellular membrane to inhibit the replication of HIV-1. However, the HIV-1 accessory protein Vpu counteracts the antiviral function of tetherin. In this study, two retroviral vector plasmids were constructed. One inhibited the vpu gene expression; the other one over-expressed the tetherin. Both retroviral vector plasmids could be packaged in the packaging cell line PT67 to obtain the corresponding retroviruses. The retroviral vector plasmids＇ functions of tetherin over-expression or vpu-RNAi were detected at the cell level. Retroviral vector plasmids were transfected to PT67 cells at different ratios from 0T3V to 3TOV, and then mixed retroviruses were harvested. The antiviral functions of mixed retroviruses were detected in HIV-1 infected TZM-bi cells. The results showed that packaged mixed retroviruses could repress the replication of HIV-1 in TZM-bl cells.

AlN Precipitates and Microstructure in Non-oriented Electrical Steels Produced by Twin-roll Casting Process

Aluminum nitride （AIN） precipitates and microstructure of 4 wt.% （Si＋AI） non-oriented electrical steel were investigated. The 2.0 mm thick cast strips with three different silicon/aluminum （Si/AI） ratios were produced by twin-roll casting process, then the strips were reheated, warm rolled, cold rolled and annealed. The microstructure and AIN precipitates were characterized using optical microscopy, scanning electron microscopy and transmission electron microscopy. The results showed that with the increase of Si/AI ratio, on the one hand, the casting microstructure changed from columnar grains to equiaxed grains, and the uniformity of annealed microstructure was improved; On the other hand, the number of AIN precipitates in cast strips reduced meanwhile the distribution became dispersed. By the reheat treatment, the size and distribution of the AIN precipitates can be changed. Moreover, the grain size of the annealed strips is in the range of 20-50 #m, at the same time, many AIN precipitates were located at grain boundaries. Therefore, controlling the Si/AI ratio is a simple method to obtain desired microstructure. Then AIN precipitates in non-oriented electrical steel prepared by twin-roll casting process hinder markedly the recrystallized grains growth, A compatible reheat treatment can be an approach worth exploring to control the behavior of AIN precipitates.

Deciphering the dynamics of the ovarian reserve in cynomolgus monkey through a quantitative morphometric study

Female reproduction and health are highly dependent on ovarian function.Ovarian reserve is a critical indicator of ovarian function[1].The ovarian reserve refers to the stock of dormant primordial follicles(primordial follicle pool)residing in the ovarian cortex[2].The primordial germ cells(PGCs)are enclosed by the basal lamina to form cyst at the beginning of ovarian development[3].

Dealloying-constructed hierarchical nanoporous bismuth-antimony anode for potassium ion batteries

Bi-Sb alloys are appealing anode materials for potassium ion batteries(PIBs)but challenged by their enormous volumetric variation during operation.Herein,a facile one-step dealloying protocol was devised and utilized to prepare the Bi-Sb alloys that manifest an exotic bicontinuous hierarchical nanoporous(np)microstructure ideal for volume-change mitigation and K+transport percolation.The growth mechanism fostering the peculiar morphology of the np-(Bi,Sb)alloys was investigated and clarified via operando X-ray(XRD)and ex-situ scanning electron microscopy(SEM).In particular,the np-Bi6Sb2 electrode,optimized for comprehensive electrochemical performance,achieves decent reversible capacities and a superior lifespan,as benchmarked with the monometallic references and other Bi-Sb alloy electrodes.The(de)potassiation mechanism of the np-(Bi,Sb)alloys was studied by operando XRD and further rationalized by density functional theory(DFT)calculations,whereby a homogeneous(segregation-free)and robust two-step electrochemically-driven phase transformations’catenation of(Bi,Sb)↔K(Bi,Sb)2↔K3(Bi,Sb)was reliably established to substantiate the outstanding reversibility of the np-(Bi,Sb)anodes in PIBs.