Impact of design of sharp non-uniform fibre Bragg gratings on system performance

A simple design of non-uniform fibre Bragg grating (FBG) with sharp reflection and low dispersion is proposed. The impact of different design solutions for ultra-square FBG-based filters on transmission system performance is investigated.     

Wide-band Fabry-Perot-like filters in optical fiber

We report the fabrication and characterization of wide-band Fabry-Perot-like resonators in optical fiber. Using Bragg gratings with variable detuning, resonators that operate ever a wavelength span in excess of 140 nm have been produced, with free spectral ranges between 0.09 nm and 11.27 nm. Numerical and experimental results for two typical resonators are presented, showing good agreement between the two     

Surface snow properties effect on millimeter-wave backscatter

The authors examine the relationship between 94-GHz backscatter from snow cover and the properties of the snow, using statistical analysis of observations made in West Germany in 1986. For terrain covered by dry snow, 94-GHz backscatter does not appear to depend significantly on any of the measured snow properties. Backscatter from wet snow is found to be sensitive to volumetric liquid water content, with the dependence inverse-exponential in form. Backscatter from wet snow is also found to depend on surface roughness, especially the cross-polarized return. Comparison of the 1986 data with similar data obtained in 1984 shows two major disagreements in the response of the vertical transmit vertical receive polarization backscattering coefficient to wet snow surface roughness, and the response of cross-polarized. The backscattering coefficient to snow surface wetness. The 1986 results are considered more reliable     

Correction to `surface snow properties effects on millimeter-wavebackscatter' (May 1988 300-306)

In the above mentioned paper (ibid., vol.26, no.3, May 1988) the exponential coefficients of percent liquid water content V_W in Table II are too large in magnitude by a factor of 10 (i.e. -0.990 should be -0.0990, etc.)     

A model for the strength of the As-deposited regions of steel weld metals

Metallurgical and Materials Transactions A - The strength of as-deposited steel weld metal, as a function of temperature, strain rate, microstructure, and alloy chemistry, has been factorized into...     

Lower acicular ferrite

An experiment has been designed to confirm that the mechanism of growth of acicular ferrite in steel welds is similar to that of bainite in ordinary steels. On the hypothesis that the growth mechanisms are identical, it was expected that if the carbon concentration of a weld is increased sufficiently, then for similar welding conditions, the microstructure should undergo a transition from acicular ferrite tolower acicular ferrite, in which the plates of acicular ferrite should contain cementite particles of the sort normally associated with lower bainite in wrought steels. An experimental weld of unusually high carbon concentration was prepared, and metallography confirmed the existence of lower acicular ferrite, supporting the conclusion that acicular ferrite is simply an intragranularly nucleated bainite.     

Classical, novel and atypical isoforms of PKC stimulate ANF- and TRE/AP-1-regulated-promoter activity in ventricular cardiomyocytes

Cultured neonatal rat ventricular myocytes were co-transfected with expression plasmids encoding protein kinase C (PKC) isoforms from each of the PKC subfamilies (classical PKC-alpha, novel PKC-epsilon or atypical PKC-zeta) together with an atrial natriuretic factor (ANF) reporter plasmid. Each PKC had been rendered constitutively active by a single Ala-->Glu mutation or a small deletion in the inhibitory pseudosubstrate site. cPKC-alpha, nPKC-epsilon or aPKC-zeta expression plasmids each stimulated ANF-promoter activity and expression of a reporter gene under the control of a 12-O-tetradecanoylphorbol 13-acetate-response element (TRE). Upregulation of the ANF promoter is characteristic of the hypertrophic response in the heart ventricle and a TRE is present in the ANF promoter. Thus all subfamilies of PKC may have the potential to contribute to hypertrophic response in cardiomyocytes.     

Very broad reflection bandwidth (44 nm) chirped fibre gratings andnarrow bandpass filters produced by the use of an amplitude mask

Chirped gratings with very broad reflection bandwidths up to 44 nm and high reflectivity have been produced holographically in boron-codoped and standard telecommunications fibres which have been hydrogen-soaked. A 2 nm wide transmission band has been produced within the broad reflection band by use of an amplitude mask during grating exposure