Geometric properties of the first singlet S-wave excited state of two-electron atoms near the critical nuclear charge

The geometric structure parameters and radial density distribution of 1s2s1S excited state of the two-electron atomic system near the critical nuclear charge Z_(c)were calculated in detail under tripled Hylleraas basis set.Contrary to the localized behavior observed in the ground and the doubly excited 2p^(23)Pe states,for this state our results identify that while the behavior of the inner electron increasingly resembles that of a hydrogen-like atomic system,the outer electron in the excited state exhibits diffused hydrogen-like character and becomes perpendicular to the inner electron as nuclear charge Z approaches Z_(c).This study provides insights into the electronic structure and stability of the two-electron system in the vicinity of the critical nuclear charge.

Multi-Stage Fluid Charging and Critical Period of Hydrocarbon Accumulation of the Sinian Dengying Formation in Central Sichuan Basin

Objective The natural gas exploration of the Sinian reservoirs in the central Sichuan Basin has made a significant breakthrough in recent years, and has thus attracted much attention among geologists. The Sichuan Basin is known to have complicated geological settings, which has experienced multiple stages of tectonic evolution, fluid charging and hydrocarbon accumulation. This research aims to determine the geochemical characteristics of each stage of fluids, the features and time interval of fluid activity in different geologic periods, and further to restore the critical period and geological age of the hydrocarbon accumulation.

Monte Carlo evaluation of spatial multiple-bit upset sensitivity to oblique incidence

We investigate the impact of heavy ion irradiation on a hypothetical static random access memory （SRAM） device. Influences of the irradiation angle, critical charge, drain-drain spacing, and dimension of device structure on the device sensitivity have been studied. These prediction and simulated results are interpreted with MUFPSA, a Monte Carlo code based on Geant4. The results show that the orientation of ion beams and device with different critical charge exert indis- pensable effects on multiple-bit upsets （MBUs）, and that with the decrease in spacing distance between adjacent cells or the dimension of the cells, the device is more susceptible to single event effect, especially to MBUs at oblique incidence.

Monte Carlo simulation based on Geant4 of single event upset induced by heavy ions

The present work is a computational simulation of single event upset(SEU) induced by heavy ions passing through the device with Geant4-tool based on Monte Carlo transport code.Key parameters affecting SEU occurrence are examined,and related geometrical construction and critical charge are quantified.The MUlti-Functional Package for SEU Analysis(MUFPSA) has been successfully programmed and applied for SEU occurrence after the completion of device geometrical construction,critical charge,and SEU cross section calculation.The proposed MUFPSA has yielded a good agreement with MRED.Specifically,the results show that higher LET incident ions lead to increased SEU vulnerability due to more diffusion and higher energy deposition.In addition,the analytical method of radial ionization profile provides a good complementary interpretation.

Reducing vulnerability to soft errors in sub-100 nm content addressable memory circuits

We first study the impacts of soft errors on various types of CAM for different feature sizes.After presenting a soft error immune CAM cell,SSB-RCAM,we propose two kinds of reliable CAM,DCF-RCAM and DCK-RCAM. In addition,we present an ignore mechanism to protect dual cell redundancy CAMs against soft errors.Experimental results indicate that the 11T-NOR CAM cell has an advantage in soft error immunity.Based on 11T-NOR,the proposed reliable CAMs reduce the SER by about 81%on average with acceptable overheads.The SER of dual cell redundancy CAMs can also be decreased using the ignore mechanism in specific applications.

A novel high reliability CMOS SRAM cell

A novel 8T single-event-upset（SEU） hardened and high static noise margin（SNM） SRAM cell is proposed. By adding one transistor paralleled with each access transistor,the drive capability of pull-up PMOS is greater than that of the conventional cell and the read access transistors are weaker than that of the conventional cell.So the hold,read SNM and critical charge increase greatly.The simulation results show that the critical charge is almost three times larger than that of the conventional 6T cell by appropriately sizing the pull-up transistors.The hold and read SNM of the new cell increase by 72%and 141.7%,respectively,compared to the 6T design,but it has a 54%area overhead and read performance penalty.According to these features,this novel cell suits high reliability applications,such as aerospace and military.