8,443 research outputs found
Increases in the Irreversibility Field and the Upper Critical Field of Bulk MgB2 by ZrB2 Addition
In a study of the influence of ZrB2 additions on the irreversibility field,
Birr and the upper critical field Bc2, bulk samples with 7.5 at. % ZrB2
additions were made by a powder milling and compaction technique. These samples
were then heated to 700-900C for 0.5 hours. Resistive transitions were measured
at 4.2 K and Birr and Bc2 values were determined. An increase in Bc2 from 20.5
T to 28.6 T and enhancement of Birr from 16 T to 24 T were observed in the ZrB2
doped sample as compared to the binary sample at 4.2 K. Critical field
increases similar to those found with SiC doping were seen at 4.2 K. At higher
temperatures, increases in Birr were also determined by M-H loop extrapolation
and closure. Values of Birr which were enhanced with ZrB2 doping (as compared
to the binary) were seen at temperatures up to 34 K, with Birr values larger
than those for SiC doped samples at higher temperatures. The transition
temperature, Tc, was then measured using DC susceptibility and a 2.5 K drop of
the midpoint of Tc was observed. The critical current density was determined
using magnetic measurements and was found to increase at all temperatures
between 4.2 K and 35 K with ZrB2 doping.Comment: 15 pages, 5 figs, 1 tabl
Holographic gratings for spectrographic applications: Study of aberrations
The design and fabrication of holographic gratings requires an understanding of Fermat's principle. This principle states that the path of a light ray from one point to another is that which requires the least time. The aberrant, optical path of an object point to an image was studied using Fermat principles
DEVELOPMENT AND VALIDATION OF SPECTROPHOTOMETRIC AND ION PAIR CHROMATOGRAPHIC TECHNIQUE FOR ESTIMATION OF VALSARTAN AND HYDROCHLOROTHIAZIDE
Two new simple, sensitive, rapid, accurate and reproducible methods (UV-spectrophotometric and ion pair chromatography) have been developed for simultaneous estimation of valsartan (VAL) and hydrochlrothiazide (HCTZ) from their tablet dosage form. The first method involves multiwavelength spectrophotometric method (Method 1) in which interference of HCTZ at 245nm (wavelength for estimation of VAL) was removed by recording absorbance difference at 245nm and 301 nm whereas HCTZ was estimated directly from its absorbance at 316 nm at which VAL shows no absorbance. Linearity of the response was demonstrated by VAL in the concentration range of 5-45 g/ml with a square correlation coefficient (r2) of 0.9998. Linearity of the response was demonstrated by HCTZ in the concentration range of 2-18 g/ml with a square correlation coefficient (r2) of 0.9994. The second method utilizes ion pair chromatography (Method 2) on a HIQ sil ODS column (250 mm* 4.6 mm i.d.) using methanol: 0.0025 M orthophosphoric acid: (70:30 by volume) having pH 4.6: 0.1% hexane sulphonic acid as mobile phase with UV detection at 259nm over concentration range for VAL is 240-0 μg/ml, and for HCTZ is 75-0μg/ml. Losartan potassium was used as the internal standard. The suggested procedures were checked using laboratory prepared mixtures and were applied successfully for the analysis of their tablet dosage form. The results of analysis were statistically analysed. Both the methods were validated as per ICH Q2B guideline
Entanglement of pure states for a single copy
An optimal local conversion strategy between any two pure states of a
bipartite system is presented. It is optimal in that the probability of success
is the largest achievable if the parties which share the system, and which can
communicate classically, are only allowed to act locally on it. The study of
optimal local conversions sheds some light on the entanglement of a single copy
of a pure state. We propose a quantification of such an entanglement by means
of a finite minimal set of new measures from which the optimal probability of
conversion follows.Comment: Revtex, 4 pages, no figures. Minor changes. Appendix remove
Gender dysphoria with homosexuality and comorbid depressive disorder: complexities in concept and management
Gender identity disorder (GID) and homosexuality are complex entities debated over decades, whether should be categorized as a disorder or not. There are a number of problems specifically related to the criteria of the GID diagnosis like differences in the terms trans-sexualism and GID, failure of the proposed criteria in conceptualizing the whole spectrum of gender variance phenomena, the potential risk of physically invasive examinations to rule out intersex conditions and the application of diagnosis even after hormonal and surgical treatment. We hereby report complexities faced in the case of a male to female transsexual with homosexuality and depressive disorder and its management
Generalized Induced Norms
Let ||.|| be a norm on the algebra M_n of all n-by-n matrices over the
complex field C. An interesting problem in matrix theory is that "are there two
norms ||.||_1 and ||.||_2 on C^n such that ||A||=max{||Ax||_2: ||x||_1=1} for
all A in M_n. We will investigate this problem and its various aspects and will
discuss under which conditions ||.||_1=||.||_2.Comment: 8 page
Extremal extensions of entanglement witnesses: Unearthing new bound entangled states
In this paper, we discuss extremal extensions of entanglement witnesses based
on Choi's map. The constructions are based on a generalization of the Choi map
due to Osaka, from which we construct entanglement witnesses. These extremal
extensions are powerful in terms of their capacity to detect entanglement of
positive under partial transpose (PPT) entangled states and lead to unearthing
of entanglement of new PPT states. We also use the Cholesky-like decomposition
to construct entangled states which are revealed by these extremal entanglement
witnesses.Comment: 8 pages 6 figures revtex4-
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