Shuhuan Liu

Fabrication of oxidized multiwalled carbon nanotubes for the immobilization of U(VI) from aqueous solutions

Herein, the surface properties of oxidized multiwalled carbon nanotubes (MWCNs) were characterized by adopting XRD, SEM and FTIR. The sorption behaviors of U(VI) from wastewater by oxidized MWCNs were investigated by adopting batch technique. The experimental results demonstrated that sorption behaviors of U(VI) on oxidized MWCNs were dependent on ionic strength at low pH, and independent of ionic strength at high pH. The ion exchange and outer-sphere surface complexation were main mechanism for sorption of U(VI) on oxidized MWCNs at low pH, whereas inner-sphere surface complexation and coinstantaneous co-precipitation were primary mechanism at high pH.

60 Co gamma radiation total ionizing dose combined with conducted electromagnetic interference studies in BJTs

Abstract The influence of combined 60Co gamma radiation total ionization dose (TID) and conducted electromagnetic interference (EMI) in bipolar transistors was studied. The BJTs were set at forward active bias during the entire irradiation processes to investigate the current gain degradation. The experimental results demonstrated that the base current increases under the influence of EMI, TID and combined TID with EMI due to the recombination currents in the emitter-base spacer of the transistor. The ideality factor n investigated showed that TID was approximately equal to 2 and the combination of TID and EMI was greater than 2. Meanwhile, the degradation quantity of the device current gain βTID+EMI tested with combined TID and EMI irradiation was observed to be more severe than that of βTID or βEMI tested only with TID or EMI at low bias VBE region ( 0.6 V) became smaller under different experimental conditions (EMI, TID, TID + EMI). Finally, the current gain degradation levels of the tested devices were compared (βTID+EMI > βTID > βEMI).

FFI4SoC: a Fine-Grained Fault Injection Framework for Assessing Reliability against Soft Error in SoC

Recently, system-on-chips (SoCs) are increasingly employed in reliable applications for their high-performance and high-densities. Moreover, the structure shrinking of SoC leads to its proneness to radiation-induced soft errors. This paper presents a fine-grained fault injection framework for SoC (FFI4SoC) to assess the reliability of SoC against soft errors. FFI4SoC facilitates fault injection for SoC by defining the primary components and rules that are required by fine-grained fault injection. Furthermore, based on FFI4SoC, we develop a fine-grained fault injection tool named SSIFFI for bare-metal MicroZed. The design of SSIFFI is presented in order to illustrate the application of FFI4SoC. Finally, SSIFFI is engaged in simulated fault injection experiments to explore the cause of single event functional interrupts (SEFIs) and to validate functional properties of FFI4SoC. The experimental results disclose detailed reasons for SEFI and prove that FFI4SoC can be employed to assess reliability of SoC well with the merit of fine-grained injection.

Measurement of single event effects induced by alpha particles in the Xilinx Zynq-7010 System-on-Chip

ABSTRACT Single event effect susceptibility of the Xilinx Zynq-7010 System-on-Chip (SoC) was investigated. Seven hardware blocks in the Zynq-7010 SoC were tested for single event effects using americium-241 alpha radiation source. Four error types, data error, single event upset and functional interrupt events, time-out, and system halt, were observed in different blocks under test. The dynamic cross sections of the different blocks were obtained and the reasons of some critical error types were analyzed.

Total Ionizing Dose Effects of SiGe HBTs Induced by 60Co Gamma-Ray Irradiation

Abstract For evaluating the SiGe heterojunction bipolar transistors (HBTs) performance during and after gamma-ray irradiation, the characteristics of the direct current (dc) gain of the test samples changed with increasing irradiation dose, and collector current injection levels during 60Co gamma irradiation were measured and analyzed. The experimental results of the typical dc and alternating current (ac) electronic parameters before and after irradiation revealed that the base current Ib, the collector current IC, the dc current gain, and the maximum oscillation frequency fmax exhibited degradation. While other electronic parameters including the cut-off frequency fT, the ac current gain |H21|, and output capacitance CBC did not exhibit any significant change compared with those of pre-irradiation. The degradation mechanisms of the typical dc and ac parameters measured in this work were primarily analyzed. The tested results of SiGe HBTs offered some reference data for evaluating the behavior of the test type of device operated in an ionizing radiation environment.

Experimental study of pulse neutron irradiation damage in SiGe HBT

ABSTRACT The response to transient irradiation of npn SiGe HBT (BG35 SiGe BiCMOS), i.e. device under test (DUT) was studied with online measurement of 1 MeV equivalent pulse neutron fluence of 0.8 × 1013n/cm2. The differently biased DUT1 and DUT2 in test circuit were irradiated in the first day with neutron fluence (0.8 × 1013n/cm2) termed as Fluence1 and with an additional neutron fluence (0.8 × 1013n/cm2) in the second day to make Fluence2 equals to 1.6 × 1013n/cm2. The experimental results show that pulsed neutron irradiation causes voltage surges in the DUTs exhibited by a negative and positive peak known to be radiation damage (RD). The RD in DUTs induced by pulse neutron Fluence1 initially created unstable displacement defects and the defects later reordered (cluster defects) to form more stable configurations via neutron Fluence2. The irradiated DUTs experienced online instantaneous annealing after 2.03 × 10−9 s and offline measurement (i.e. without irradiation) of DUTs showed recovery to normal mode of operation after 24 h annealing. The level of pulse peaks in the base voltage terminals of DUT1 and DUT2 were compared as Vb2Fluence1 > Vb1Fluence1 and Vb2Fluence2 > Vb1Fluence2. A comprehensive analysis of RD region in DUTs with reference to Area (A1, A2), Peak (P1, P2), Height (H), and Full width at half maximum (FWHM) were investigated.

A Fine-Grained Software-Implemented DMA Fault Tolerance for SoC Against Soft Error

In system-on-chips (SoCs), DMA, as a peripheral module, plays an important role in data transmission. However, the structure shrinking of SoC leads to its proneness to radiation-induced soft errors, especially for DMA. This paper presents a fine-grained software-implemented fault tolerance for SoC, named DCRH, to enhance the reliability of DMA against soft errors. DCRH achieves fine-grained selective fault tolerance, protecting DMA without interfering other modules of SoC. Furthermore, it is transparent to the user application because it performs on driver layer. In this paper, we present our fault source analysis for DMA based on Xilinx Zynq-7010 SoC and the detailed design of DCRH. The method is then applied to bare-metal MicroZed so that a DCRH-enhanced DMA driver is developed. Finally, SSIFFI is engaged in the simulated DMA fault injection experiments to validate DCRH. The experimental results prove that DCRH can achieve high fault coverage for DMA, above 97%, with stable performance.

Hot carrier effect on a single SiGe HBT's EMI response

Abstract This paper describes the rectification responses exhibited by two kinds of SiGe HBTs when electromagnetic interference (EMI) is injected at the base of the transistor. The variation of the EMI induced DC offset after hot carrier stress is also studied. The experimental results show that the EMI response of a single SiGe HBT is different from that of a Si BJT. With interference present, the DC current gain increases at low base-emitter (BE) bias and decreases at larger VBE values. The absence of AC crowding induced DC crowding along with the base recombination current accounts for the increase of current gain. The base-width effect and the high-injection effect tend to decrease the gain in presence of interference. The simulation results show that the Gummel–Poon model is able to quantitatively model the EMI response of a SiGe HBT.

Primary Simulation: The Yield of 14C Produced in PWR During Normal Operation

The mechanisms of the radionuclide 14C production and releasing from pressurized water reactor (PWR) nuclear power plant (NPP) are simply described in the paper. The yield calculation model for 14C produced in PWR is offered in this work. The averaged neutron flux in reactor core under normal operation condition is simulated with MCNP5 according to the simplified Daya Bay NPP reactor core structure and other parameters, the yields and activities of 14C in different parts of the reactor core including fuel, fuel cladding, nitrogen impurities in fuel and coolant are calculated and compared with Origen2. The simulation results showed that the yields of 14C produced in different parts change linearly with operation time. The rations of 14C introduced by nuclear reactions in coolant, fuel cladding, nitrogen impurities in fuel and fuel element core are 64%, 16%, 12%and 8%, respectively. The dominant part of 14C is induced by neutron reactions with coolant. The primary study results may offer some reference values for 14C releasing in environment control from NPP.Copyright

Studies on the Responses of CR-39 Detector to C3+, O3+, and Proton Irradiations

In the present study, CR-39 detectors with thickness of 1.0mm are irradiated respectively by C3+(10MeV, 20MeV, 20MeV), O3+(10MeV, 20MeV, 30MeV) particles and protons (5MeV) with ion fluences ranging from 1.0×107cm−2 to 5.0×109cm−2. The etching time conditions of the latent tracks for the different irradiation particles with different fluences described above are experimental studied. The curves for track density distributions with irradiation fluences of different energy particles are simulated. The suggested irradiation fluences ranges for the three types of particles detected with CR-39 detector are offered according to the measurement results.Copyright