Resonant Raman of OH/OD vibrations and photoluminescence studies in LiTaO3 thin film

Resonant Raman spectra (RRS) of O-H and O-D vibration and libration modes, their combinations and higher harmonics have been observed in LiTaO3 polycrystalline thin films. RRS peaks are superimposed on photoluminescence (PL) spectrum. Monochromatic light from a xenon lamp is used as excitation source. PL spectrum shows two broad peaks, first near the band gap in UV (4.4-4.8eV) and another in the sub band gap region (< 4.0 eV). Band gap PL along with RRS peaks are reported for the first time. Photoluminescence excitation spectrum (PLE) shows a peak at 4.8 eV. Peak positions and full width at half maximum (FWHM) of RRS peaks depend upon the excitation energy. Dispersions of the fundamental and the third harmonic of the stretching mode of O-H with excitation energy are about 800 cm-1/eV and 2000 cm-1/eV respectively. This dispersion is much higher than reported in any other material.Comment: 20 page

Patterns in Southeast Florida Coral Reef Community Composition

The Southeast (SE) Florida coral reef system is the northern extension of the Florida reef tract. This high latitude system lies offshore a heavily populated and urbanized coast and therefore is affected by numerous environmental and anthropogenic stressors. Using annual monitoring data collected in 2004, the southeast lorida reef community was analyzed to investigate patterns in community composition in various habitat types. Data was collected by SCUBA divers who conducted a 30m2 belt transect survey at 24 sample sites offshore Broward County (SE), Florida. Sites ranged in depth range from six to 18 meters. The 24 sites occurred on five different reef habitat categories: ridge-shallow, colonized pavement-shallow, linear inner reef, linear middle reef, and linear outer reef. These sites were established for the Broward County Board of County Commissioners and Environmental Protection and Growth Management Department, Biological Resources Division, in order to monitor Broward County coral communities and sedimentation rates in relation to possible effects from a beach renourishment project. The assessment took place prior to the renourishment project

A Novel Technique of Uterine Manipulation in Laparoscopic Pelvic Oncosurgical Procedures: “The Uterine Hitch Technique”

Aim. To describe a new technique of uterine manipulation in laparoscopic management of pelvic cancers. Material and Methods. We used a novel uterine hitch technique in 23 patients from May 2008 to October 2008. These patients underwent pelvic oncologic surgery including laparoscopic radical hysterectomy (n = 7), laparoscopic anterior resection (n = 4), laparoscopic abdominoperineal resection (n = 3), laparoscopic posterior exenteration (n = 4), or laparoscopic anterior exenteration (n = 5). The uterus was hitched to the anterior abdominal.wall by either a single suture in the fundus or by sutures through the round ligaments. Results. The uterine hitch technique was successfully accomplished in all procedures. It was performed in less than 5 minutes in all cases. It obviated the need for vaginal manipulation. An extra port for retraction could be avoided. There were no intraoperative complications. Conclusion. A practical, cheap and reproducible method for uterine manipulation, during pelvic oncologic surgery is described. It improves the stability of the uterus and also obviates the need for keeping an additional assistant for vaginal manipulation in any of the procedures

Distortion Analysis of CMOS Based Analog Circuits

The amplifiers are the vital part of the analog circuit designs. The linearity of the CMOS is of most important concern in the design of many analog circuits. There are several aspects regarding nonlinear distortion analysis in analog circuits implemented in CMOS technology. Basically, the investigations visualize the nature of the total harmonic distortion (THD) dependence on the amplitude and frequency of the input signals. In this paper, the basic building blocks of analog integrated circuits such as Common source amplifier with diode connected load and Differential amplifier with current mirror load have been presented for distortion analysis. The MOSFET model used for simulation is BSIM3 SPICE model from 0.13-μm and BSIM4 SPICE model from 22-μm CMOS process technology. HSPICE circuit simulator tool is used for distortion analysis of CMOS circuits. It is evident that the above function gives remarkable insight of the nonlinear behavior of the considered circuits and it is worth considering for further investigations

Estimation of a probability in inverse binomial sampling under normalized linear-linear and inverse-linear loss

Sequential estimation of the success probability $p$ in inverse binomial sampling is considered in this paper. For any estimator $\hat p$, its quality is measured by the risk associated with normalized loss functions of linear-linear or inverse-linear form. These functions are possibly asymmetric, with arbitrary slope parameters $a$ and $b$ for $\hat pp$ respectively. Interest in these functions is motivated by their significance and potential uses, which are briefly discussed. Estimators are given for which the risk has an asymptotic value as $p$ tends to $0$, and which guarantee that, for any $p$ in $(0,1)$, the risk is lower than its asymptotic value. This allows selecting the required number of successes, $r$, to meet a prescribed quality irrespective of the unknown $p$. In addition, the proposed estimators are shown to be approximately minimax when $a/b$ does not deviate too much from $1$, and asymptotically minimax as $r$ tends to infinity when $a=b$.Comment: 4 figure

Multiple exciton generation in VO2

Multiple exciton generation (MEG) is a widely studied phenomenon in semiconductor nanocrystals and quantum dots, aimed at improving the energy conversion efficiency of solar cells. MEG is the process wherein incident photon energy is significantly larger than the band gap, and the resulting photoexcited carriers relax by generating additional electron-hole pairs, rather than decaying by heat dissipation. Here, we present an experimental demonstration of MEG in a prototype strongly correlated material, VO2, through photocurrent spectroscopy and ultrafast transient reflectivity measurements, both of which are considered the most prominent ways for detecting MEG in working devices. The key result of this paper is the observation of MEG at room temperature (in a correlated insulating phase of VO2), and the estimated threshold for MEG is 3Eg. We demonstrate an escalated photocurrent due to MEG in VO2, and quantum efficiency is found to exceed 100%. Our studies suggest that this phenomenon is a manifestation of expeditious impact ionization due to stronger electron correlations and could be exploited in a large number of strongly correlated materials.Comment: 6 pages, 5 figures, Physical Review

Transverse Electronic Transport through DNA Nucleotides with Functionalized Graphene Electrodes

Graphene nanogaps and nanopores show potential for the purpose of electrical DNA sequencing, in particular because single-base resolution appears to be readily achievable. Here, we evaluated from first principles the advantages of a nanogap setup with functionalized graphene edges. To this end, we employed density functional theory and the non-equilibrium Green's function method to investigate the transverse conductance properties of the four nucleotides occurring in DNA when located between the opposing functionalized graphene electrodes. In particular, we determined the electrical tunneling current variation as a function of the applied bias and the associated differential conductance at a voltage which appears suitable to distinguish between the four nucleotides. Intriguingly, we observe for one of the nucleotides a negative differential resistance effect.Comment: 19 pages, 7 figure

Neutron dark-field imaging of hydrogen-fatigued pressure vessel steel

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