Effects of annealing on the electrical properties of Fe-doped InP

The electrical properties of Fe-doped semi-insulating (SI) InP were investigated before and after annealing. The annealing conditions were controlled by changing either the temperature or duration. Correlation between the change of electrical parameters with the change of defect concentration at different annealing stage was observed. The defects and the change of the concentrations in Fe-doped SI InP were detected by room-temperature photocurrent spectroscopy.published_or_final_versio

Electrical and FT-IR measurements of undoped N-type INP materials grown from various stoichiometric melts

P-rich, In-rich and Stoichiometric undoped InP melts have been synthesed by phosphorus in-situ injection method. InP crystal ingots have been grown from these melts by Liquid Encapsulated Czochralski (LEC). Samples from these ingots grown from various Stoichiometric melts have been characterized by Hall Effect and Fourier Transform Infrared (FT-IR) spectroscopy measurements respectively. The Hall Effect measurement results indicate that the net carrier concentration of P-inch undoped InP is higher than that of In-rich and Stoichiometric undoped InP materials. FT-IR spectroscopy measurements reveal that there are intensive absorption peaks which have been proved to be hydrogen related indium vacancy complex V InH 4. By comparing FT-IR spectra, it is found that P-rich InP material has the most intensive absorption peak of V InH 4, while In-rich InP material has the weakest absorption peak.published_or_final_versio

Formation of P In defect in annealed liquid-encapsulated Czochralski InP

Fourier transform infrared spectroscopy measurements have been carried out on liquid-encapsulated Czochralski-grown undoped InP wafers, which reproducibly become semi-insulating upon annealing in an ambient of phosphorus at 800-900°C. The measurements reveal a high concentration of hydrogen complexes in the form V InH 4 existing in the material before annealing in agreement with recent experimental studies. It is argued that the dominant and essential process producing the semi-insulating behavior is the compensation produced by an EL 2-like deep donor phosphorus antisite defect, which is formed by the dissociation of the hydrogen complexes during the process of annealing. The deep donor compensates acceptors, the majority of which are shallow residual acceptor impurities and deep hydrogen associated V In and isolated V In levels, produced at the first stage of the dissociation of the V InH 4 complex. The high concentration of indium vacancies produced by the dissociation are the precursor of the EL 2-like phosphorus antisite. These results show the importance of hydrogen on the electrical properties of InP and indicate that this largely results from low formation energy of the complex V InH 4 in comparison with that of an isolated V In. © 1998 American Institute of Physics.published_or_final_versio

Molecular phylogenetic analysis of key Jatropha species inferred from nrDNA ITS and chloroplast (trnL-F and rbcL) sequences

The genus Jatropha (Euphorbiaceae) contains species that are of significant economic and ornamental value. However, Jatropha breeding material is rather limited due to incomplete information regarding phylogenetic relationships among germplasm resources. Phylogenetic analyses were performed based on the internal transcribed spacer of nuclear ribosomal DNA (nrDNA ITS), two chloroplast regions (trnL-F and rbcL), and the combined (ITS+trnL-F+rbcL) dataset among twenty-five specimens representing six key Jatropha species. Phylogenetic relationships of Jatropha were well resolved between subgenus Curcas and subgenus Jatropha, and demonstrated the intermediate position of section Polymorphae among sections of both subgenera. Jatropha curcas and J. integerrima demonstrated a close phylogenetic relationship. The molecular data agreed with the morphological classification that recognized J. multifida and J. podagrica in sec. Peltatae. The distinct intraspecific divergence that occurred in J. curcas could be attributed to restricted gene flow caused by geographical isolation and different ecological conditions. Phylograms produced with trnL-F and rbcL sequence data suggested slow rates of sequence divergence among Jatropha spp., while the ITS gene tree had good resolution suggesting high genetic variation of ITS among Jatropha species

Multi-site campaign for transit timing variations of WASP-12 b: possible detection of a long-period signal of planetary origin

The transiting planet WASP-12 b was identified as a potential target for transit timing studies because a departure from a linear ephemeris was reported in the literature. Such deviations could be caused by an additional planet in the system. We attempt to confirm the existence of claimed variations in transit timing and interpret its origin. We organised a multi-site campaign to observe transits by WASP-12 b in three observing seasons, using 0.5-2.6-metre telescopes. We obtained 61 transit light curves, many of them with sub-millimagnitude precision. The simultaneous analysis of the best-quality datasets allowed us to obtain refined system parameters, which agree with values reported in previous studies. The residuals versus a linear ephemeris reveal a possible periodic signal that may be approximated by a sinusoid with an amplitude of 0.00068+/-0.00013 d and period of 500+/-20 orbital periods of WASP-12 b. The joint analysis of timing data and published radial velocity measurements results in a two-planet model which better explains observations than single-planet scenarios. We hypothesize that WASP-12 b might be not the only planet in the system and there might be the additional 0.1 M_Jup body on a 3.6-d eccentric orbit. A dynamical analysis indicates that the proposed two-planet system is stable over long timescales.Comment: Accepted for publication in A&

Light hadron, Charmonium(-like) and Bottomonium(-like) states

Hadron physics represents the study of strongly interacting matter in all its manifestations and the understanding of its properties and interactions. The interest on this field has been revitalized by the discovery of new light hadrons, charmonium- and bottomonium-like states. I review the most recent experimental results from different experiments.Comment: Presented at Lepton-Photon 2011, Mumbai, India; 21 pages, 18 figures; add more references; some correctio

Live Bird Exposure among the General Public, Guangzhou, China, May 2013

Background A novel avian-origin influenza A(H7N9) caused a major outbreak in Mainland China in early 2013. Exposure to live poultry was believed to be the major route of infection. There are limited data on how the general public changes their practices regarding live poultry exposure in response to the early outbreak of this novel influenza and the frequency of population exposure to live poultry in different areas of China. Methodology This study investigated population exposures to live birds from various sources during the outbreak of H7N9 in Guangzhou city, China in 2013 and compared them with those observed during the 2006 influenza A(H5N1) outbreak. Adults were telephone-interviewed using two-stage sampling, stratified by three residential areas of Guangzhou: urban areas and two semi-rural areas in one of which (Zengcheng) A(H7N9) virus was detected in a chicken from wet markets. Logistic regression models were built to describe practices protecting against avian influenza, weighted by age and gender, and then compare these practices across residential areas in 2013 with those from a comparable 2006 survey. Principal Findings Of 1196 respondents, 45% visited wet markets at least daily and 22.0% reported buying live birds from wet markets at least weekly in April-May, 2013, after the H7N9 epidemic was officially declared in late March 2013. Of those buying live birds, 32.3% reported touching birds when buying and 13.7% would slaughter the poultry at home. Although only 10.1% of the respondents reported raising backyard birds, 92.1% of those who did so had physical contact with the birds they raised. Zengcheng respondents were less likely to report buying live birds from wet markets, but more likely to buy from other sources when compared to urban respondents. Compared with the 2006 survey, the prevalence of buying live birds from wet markets, touching when buying and slaughtering birds at home had substantially declined in the 2013 survey. Conclusion/Significance Although population exposures to live poultry were substantially fewer in 2013 compared to 2006, wet markets and backyard poultry remained the two major sources of live bird exposures for the public in Guangzhou in 2013. Zengcheng residents seemed to have reduced buying live birds from wet markets but not from other sources in response to the detection of H7N9 virus in wet markets.published_or_final_versio

Compensation defects in annealed undoped liquid encapsulated Czochralski InP

As-grown undoped n-type semiconducting and annealed undoped semi-insulating (SI) liquid encapsulated Czochralski (LEC) InP has been studied by temperature dependent Hall measurement, photoluminescence spectroscopy, infrared absorption, and photocurrent spectroscopy. P-type conduction SI InP can frequently be obtained by annealing undoped LEC InP. This is caused by a high concentration of thermally induced native acceptor defects. In some cases, it can be shown that the thermally induced n-type SI property of undoped LEC InP is caused by a midgap donor compensating for the net shallow acceptors. The midgap donor is proposed to be a phosphorus antisite related defect. Traps in annealed SI InP have been detected by photocurrent spectroscopy and have been compared with reported results. The mechanisms of defect formation are discussed. © 1999 American Institute of Physics.published_or_final_versio

Set optimization - a rather short introduction

Recent developments in set optimization are surveyed and extended including various set relations as well as fundamental constructions of a convex analysis for set- and vector-valued functions, and duality for set optimization problems. Extensive sections with bibliographical comments summarize the state of the art. Applications to vector optimization and financial risk measures are discussed along with algorithmic approaches to set optimization problems

Clinical, Virological and Immunological Features from Patients Infected with Re-Emergent Avian-Origin Human H7N9 Influenza Disease of Varying Severity in Guangdong Province

The second wave of avian influenza H7N9 virus outbreak in humans spread to the Guangdong province of China by August of 2013 and this virus is now endemic in poultry in this region.Background The second wave of avian influenza H7N9 virus outbreak in humans spread to the Guangdong province of China by August of 2013 and this virus is now endemic in poultry in this region. Methods Five patients with H7N9 virus infection admitted to our hospital during August 2013 to February 2014 were intensively investigated. Viral load in the respiratory tract was determined by quantitative polymerase chain reaction (Q-PCR) and cytokine levels were measured by bead-based flow cytometery. Results Four patients survived and one died. Viral load in different clinical specimens was correlated with cytokine levels in plasma and broncho-alveolar fluid (BALF), therapeutic modalities used and clinical outcome. Intravenous zanamivir appeared to be better than peramivir as salvage therapy in patients who failed to respond to oseltamivir. Higher and more prolonged viral load was found in the sputum or endotracheal aspirates compared to throat swabs. Upregulation of proinflammatory cytokines IP-10, MCP-1, MIG, MIP-1α/β, IL-1β and IL-8 was found in the plasma and BALF samples. The levels of cytokines in the plasma and viral load were correlated with disease severity. Reactivation of herpes simplex virus type 1(HSV-1) was found in three out of five patients (60%). Conclusion Expectorated sputum or endotracheal aspirate specimens are preferable to throat swabs for detecting and monitoring H7N9 virus. Severity of the disease was correlated to the viral load in the respiratory tract as well as the extents of cytokinemia. Reactivation of HSV-1 may contribute to clinical outcome.published_or_final_versio