Ultra-fast silicon detectors (UFSD) are a specialized type of radiation detectors based on Low Gain Avalanche Detectors (LGADs) that are designed to have extremely fast response times. This work ...presents detailed results on the study of 50μm thin-LGADs with different doping concentrations produced by Micron Semiconductors Ltd. A temperature dependent study of electrical characteristics and infrared laser measurements are presented in this work.
Comparison of surface effects in bare and titanium oxide coated CoFe2O4 nanoparticles has been done with the help of magnetic measurements. The average crystallite size was 31 for bare CoFe2O4 ...nanoparticles. For titanium oxide coated nanoparticles, the CoFe2O4 and titanium oxide phases have crystallite size of 46 and 38 nm, respectively. TEM images confirmed the coating behavior of titanium oxide on CoFe2O4 nanoparticles. Both kinds of nanoparticles were in magnetically blocked state at room temperature as evident by ZFC/FC measurements. The effective anisotropy constant was calculated from simulated ZFC curve and found higher for bare CoFe2O4 nanoparticles due to large surface spin disorder and strong interparticle interactions. In modified Bloch's law fit for Ms vs. T data, the higher value of Bloch's constant for titanium oxide coated CoFe2O4 nanoparticles demonstrates the weak exchange coupling constant J. The Kneller's law fit for Hc vs. T data showed a lower value of constant α for titanium oxide coated CoFe2O4 nanoparticles which is due to the reduced surface magnetic and weak interparticle interactions. In summary, crystalline titanium oxide coating on CoFe2O4 nanoparticles showed reduction in surface spin disorder and weaken interparticle interactions.
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•Surface effects get reduced in titanium oxide coated CoFe2O4 nanoparticles.•Particle size is not reduced in titanium oxide coated CoFe2O4 nanoparticles.•The titanium oxide coating has reduced the surface defects and interparticle interactions.
The magnetic properties of nickel ferrite (NiFe
2
O
4
) nanoparticles (NPs) and its composite with titanium oxide (TiO
2
) have been studied in detail. The average crystallite size was found to be ~ ...32 nm for NiFe
2
O
4
NPs with and without presence of TiO
2
and confirmed that TiO
2
did not affect the crystalline growth of NiFe
2
O
4
NPs. The transmission electron microscopy confirmed the spherical morphology of NPs, whereas the selected area electron diffraction patterns confirmed the polycrystalline nature of these NPs. The zero-field cooled and field cooled magnetization curves confirmed that the blocking temperature lies above the room temperature for both the samples. The gradual increase of magnetization in field cooled curve at low temperatures for NiFe
2
O
4
/TiO
2
nanocomposites (NCs) indicates the reduced inter-particle magnetic interactions. The value of saturation magnetization was found to be same for both NiFe
2
O
4
NPs and NiFe
2
O
4
/TiO
2
NCs after subtracting the mass contribution of TiO
2
which is non-magnetic in nature. The higher value of fitting parameter B in Bloch’s law fit for NiFe
2
O
4
/TiO
2
NCs indicates the weak exchange coupling constant (J). As the average crystallite size of NiFe
2
O
4
NPs is same with and without presence of TiO
2
, the lower value of blocking temperature for NiFe
2
O
4
/TiO
2
NCs indicates the lower value of effective anisotropy constant and reduced surface effects caused by TiO
2
. In summary, NiFe
2
O
4
/TiO
2
NCs showed reduced inter-particle interactions and reduced surface effects.
Typhoid and paratyphoid fever continue to significantly contribute to global morbidity and mortality. Disease burden is higher in low-and middle-income settings where surveillance programs are rare ...and little systematic information exists at population level. This review evaluates national, regional, and global trends in the incidence of typhoid fever and of related morbidity and mortality. A literature search in Medline, Embase, and Web of Science was conducted in June 2016, followed by screening and data extraction in duplicate. Studies reporting blood culture estimates of typhoid or paratyphoid morbidity and mortality were included in the analysis. Our search yielded 5,563 unique records, of which 1978 were assessed for relevance with 219 records meeting the eligibility criteria.
serotype Typhi was the most commonly reported organism (91%), with the occurrence of typhoidal
(either incidence or prevalence) being the most commonly reported outcome (78%), followed by typhoid fever mortality, ileal perforation morbidity, and perforation mortality, respectively. Fewer than 50% of studies stratified outcomes by age or urban/rural locality. Surveillance data were available from 29 countries and patient-focused studies were available from 32 countries. Our review presents a mixed picture with declines reported in many regions and settings but with large gaps in surveillance and published data. Regional trends show generally high incidence rates in South Asia, sub-Saharan Africa, and East Asia and Pacific where the disease is endemic in many countries. Significant increases have been reported in certain countries but should be explored in the context of long-term trends and underlying at-risk populations.
Comparison of the magnetic properties of uncoated and silica (SiO2) coated barium hexaferrite (BaFe12O19) nanoparticles (NPs) have been discussed in detail. Hexagonal structure of BaFe12O19 NPs was ...confirmed by x-ray diffraction (XRD) analysis. The average crystallite size of SiO2 coated BaFe12O19 NPs was reduced due to non-magnetic SiO2 in situ coating which restrict the particle size growth. Scanning electron microscopy (SEM) images revealed that the NPs are non-spherical and elongated in shape. Saturation magnetization (MS) showed lowered value for SiO2 coated NPs. Temperature dependent MS data was analyzed with the help of Bloch's law for both the samples. The Bloch's constant β value for SiO2 coated BaFe12O19 NPs was higher as compared to the obtained value for uncoated NPs was attributed to reduced exchange coupling in coated NPs. Temperature dependent coercivity (HC) and remanence (Mr) data for both uncoated and SiO2 coated BaFe12O19 NPs showed increasing trend at lower temperature due to strong surface anisotropy. SiO2 coated NPs becomes superparamagnetic above 150 K as manifested by a diminishing HC and Mr The temperature dependent HC trend was analyzed by Kneller's law for both the samples. The uncoated NPs showed higher value of HC = 400 Oe as compared to SiO2 coated due to blocking of large size NPs. The SiO2 coated NPs exhibited relatively lower blocking temperature as compared to uncoated NPs which is attributed to smaller size of coated NPs. In summary, all these measurements showed that SiO2 coating reduced the average particle size, reduced exchange interactions and facilitate the production of superparamagnetic NPs of hard BaFe12O19 NPs.
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