A comparative study between x-rays and gamma-rays irradiation on electrical characteristics of bipolar junction transistors (BJTS)

Irradiation impact of gamma rays and X-rays on bipolar junction transistors (BJTs) in terms of electronic excitation due to transfer of energy and subsequent ionization, as well as energy transfer to atomic nuclei is studied using in-situ method. Comparison is made on the electrical characteristics of the devices under test (DUT) for various collecting current at two different operating mode. Both temporary and permanent damages in DUTs are found to be induced by energy transfer from the irradiation by gamma-rays and X-rays, depending upon total dose absorbed and current drive. Increased probability of recombination, due to creation of electron–hole pairs at the base region is found to be the most significant radiation damage in BJTs, as it leads to decrease in electron flux reaching the collector region

Compressive Phase Contrast Tomography

When x-rays penetrate soft matter, their phase changes more rapidly than their amplitude. In- terference effects visible with high brightness sources creates higher contrast, edge enhanced images. When the object is piecewise smooth (made of big blocks of a few components), such higher con- trast datasets have a sparse solution. We apply basis pursuit solvers to improve SNR, remove ring artifacts, reduce the number of views and radiation dose from phase contrast datasets collected at the Hard X-Ray Micro Tomography Beamline at the Advanced Light Source. We report a GPU code for the most computationally intensive task, the gridding and inverse gridding algorithm (non uniform sampled Fourier transform).Comment: 5 pages, "Image Reconstruction from Incomplete Data VI" conference 7800, SPIE Optical Engineering + Applications 1-5 August 2010 San Diego, CA United State

Effects of total Dose irradiation on Semiconductor devices

The amount of ionizing radiation that semiconductor devices encounter during their lifecycle degrades both of their functional and electrical parameter performances. The different radiation environments either in space, high energy physics experiments, nuclear environment or fabrication process as well as for standard terrestrial operation possess an impact on the devices. This makes that the devices based on III-V semiconductors are probable to be critical components of future electronic systems as the demand for greater robustness and susceptibility to well function in rigorous radiation environments continue to increase. Expanding electronic systems into such radiation environments requires a full understanding of the effects that ionizing radiation will have on the semiconductor properties. In this research, analytical studies of the effects of ionizing radiation introduced in commercial-off-the shelf (COTS) NPN bipolar junction transistors (BITs) and optoelectronic devices by ionizing radiation, Cobalt- 60 (60Co) gamma (y) rays and x-rays had been performed. The Total Ionizing Dose (TID) effects are cumulative and gradually take place throughout the lifecycle of the devices exposed to radiation. Ionizing radiation causes ionization by possesses enough energy to break the atomic bonds which in turn create electrons and holes pairs in the devices. This phenomenon leads to ionizing damage as a result of trapping of excess charges on or near the surfaces of their insulating layers and interfaces. At the end of this testing, the devices under test (OUT) were found to undergo performance and also temporarily degradation in both of their functional and electrical parameters due to the accumulated total dose effects. These damaging effects were depending on their driving current and also the Total TID absorbed

Modification in Structural and Optical Properties of Erbium-doped Zinc Sodium Tellurite Glass: Effect of Bimetallic Nanoparticles

The demand in accomplishing modified structural and optical features of trivalent rare earth (RE) ions doped amorphous media through the incorporation of metallic nanoparticles (NPs) of controlled sizes is ever-increasing for short wavelength solid state lasers development. In this view, we attempt to alter the optical properties of bimetallic NPs and erbium (Er3+) integrated zinc-sodium-tellurite glass. Modifications in structural properties are triggered via precise control of titanium and copper NPs nucleation and growth processes underneath the amorphous matrix. The changes in ligand interactions in the fragile disordered matrix are found to be accountable for the variations in structural and optical properties. A series of glass with composition of (70-x-y)TeO2-20ZnO-9Na2O-1Er2O3-(x)CuO-(y)TiO2 (x = 0.0 and 0.04 mol%; y = 0.0 and 0.1 mol%) are prepared following melt-quenching method and characterized. UV-Vis-NIR spectra displayed seven absorption bands corresponding to the transitions from ground state (4I15/2) to 4F5/2, 4F7/2, 2H11/2, 4S3/2, 4F9/2, 4I9/2 and 4I11/2 excited states of Er3+. FTIR spectra show the presence of symmetric Te-O-Te linkage vibrations and stretching vibrations of Cu-O on monoclinic CuO, Te-O bond of the trigonal bypiramidal unit [TeO4] with non-bridging oxygen symmetrical TeO3 groups and vibrations of water molecule. The presence of bimetallic NPs is confirmed from transmission electron microscopy (TEM) imaging. Our glass composition demonstrating such significant modification in structural and optical properties may be beneficial for the development of plasmonic devices

Real Time Particulate Matter Concentration Measurement using Laser Scattering

Particulate Matter (PM) is the sum of all solid and liquid particles suspended in air. It can be classified into PM1.0, PM2.5, and PM10 based on the size of the particles. Smaller particles are extremely hazardous as they can penetrate into our respiratory system causing adverse health effects. In this paper, a real time, portable and cost effective PM sensor system is designed for the monitoring of air particulate matter concentration. To achieve the objectives, a particulate matter monitoring device was constructed using PM Sensor SEN0177, Temperature and Humidity Sensor DHT11, Arduino Mega, DS1307 RTC and TFT LCD for data visualization. The system can simultaneously measure the concentration of PM at varying sizes. Besides, it is also equipped to measure RH and ambient air temperature. Built in real time clock and data logging system was also included as added function. The system employs a real time monitoring system for particulate matter using laser scattering technique and interfaced using MIE theory algorithm. The completed prototype was tested with TE 600 PM10 Air Sampler and General consumer for accuracy test. The system offers particulate matter detection based on laser scattering principle with a considerable accuracy of 87.7% in comparison when being compared with the TE6001 PM10 air sampler. The main advantage of this system is its ability to provide real time monitoring to obtain in situ data on the PM concentration together with RH and temperature readings which are crucial factors in the air quality monitoring

The effect of early broad-spectrum versus delayed narrow-spectrum antibiotic therapy on the primary cure rate of acute infection after osteosynthesis

Purpose: Infection near metal implants is a problem that presents challenging treatment dilemmas for physicians. The aim of this study was to analyse the efficacy of two treatment protocols for acute fracture-related infections. Methods: Seventy-one patients in two level-1 trauma centres in the Netherlands were retrospectively included in this study. These trauma centres had different standardised protocols for acute infection after osteosynthesis: 39 patients were selected from protocol A and 32 from protocol B. Both protocols involve immediate surgical debridement and soft tissue coverage, but differ in antibiotic approach: (A) immediate empirical combination antibiotic therapy with rifampicin, or (B) postponed (1–5 days) targeted antibiotic therapy. The primary outcome of these protocols was success, defined as a fracture healing in the absence of infection. The secondary outcome was antibiotic resistance patterns. Logistic regression was conducted on patients and treatment-related factors in association with primary success. Results: Primary success was achieved in 72% of protocol A patients, in 47% of those in protocol B (P = 0.033), and with prolongation of treatment success was achieved in 90% and 78% of patients, respectively. Protocol A exhibited a better primary success rate (adjusted OR 3.45, CI 1.13–10.52) when adjusted for age and soft tissue injury. There was no significant difference in antibiotic resistance between the two protocols. Conclusion: Both protocols yielded high overall success rates. Immediate empirical antibiotics can be used safely without additional bacterial resistance and may contribute to increased success rates

Nursing Home Residents and Enterobacteriaceae Resistant to Third-Generation Cephalosporins

Limited data identify the risk factors for infection with Enterobacteriaceae resistant to third-generation cephalosporins among residents of long-term-care facilities. Using a nested case-control study design, nursing home residents with clinical isolates of Enterobacteriaceae resistant to third-generation cephalosporins were compared to residents with isolates of Enterobacteriaceae susceptible to third-generation cephalosporins. Data were collected on antimicrobial drug exposure 10 weeks before detection of the isolates, facility-level demographics, hygiene facilities, and staffing levels. Logistic regression models were built to adjust for confounding variables. Twenty-seven case-residents were identified and compared to 85 controls. Exposure to any cephalosporin (adjusted odds ratio [OR] 4.0, 95% confidence interval [CI] 1.2 to13.6) and log percentage of residents using gastrostomy tubes within the nursing home (adjusted OR 3.9, 95% CI 1.3 to 12.0) were associated with having a clinical isolate resistant to third-generation cephalosporins