Phase shifts that accompany total internal reflection at a dielectric-dielectric interface

The absolute, average, and differential phase shifts that p- and s-polarized light experience in total internal reflection (TIR) at the planar interface between two transparent media are considered as functions of the angle of incidence phi. Special angles at which quarter-wave phase shifts are achieved are determined as functions of the relative refractive index N. When the average phase shift equals pi/2, the differential reflection phase shift delta is maximum, and the reflection Jones matrix assumes a simple form. For N > square root 3, the average and differential phase shifts are equal (hence deltap = 3 deltas) at a certain angle phi that is determined as a function of N. All phase shifts rise with infinite slope at the critical angle. The limiting slope of the delta-versus-phi curve at grazing incidence (partial partial differential delta/partial partial differential phi)phi=90 degrees = -(2/N)(N2 - 1)1/2 = -2 cos phic, where phic is the critical angle and (partial partial differential2 delta/partial partial differential phi 2)phi=90 degrees = 0. Therefore delta is proportional to the grazing incidence angle theta = 90 degrees - phi (for small theta) with a slope that depends on N. The largest separation between the angle of maximum delta and the critical angle is 9.88 degrees and occurs when N = 1.55377. Finally, several techniques are presented for determining the relative refractive index N by using TIR ellipsometry.     

Experimental research on the behaviour of high frequency fatigue in concrete

Calculating the fatigue strength of concrete under the cyclic load of vehicles when designing bridges is an issue which is receiving more and more attention from many engineers and researchers. Based on this fact, fatigue tests of plain concrete under constant-amplitude and stepping-amplitude cyclic loads were conducted. The mechanism which damages plain concrete specimens under high frequency fatigue loads was analysed and a non-linear accumulative fatigue formula that causes the damage was proposed. A fatigue equation P–S–N that considers the failure probability p′ was given. The results of this research are a good preparation for further studies into high frequency fatigue tests of concrete cylinders reinforced with carbon fibre.     

Three-dimensional polarization states of monochromatic light fields

The 3×1 generalized Jones vectors (GJVs) [E(x) E(y) E(z)](t) (t indicates the transpose) that describe the linear, circular, and elliptical polarization states of an arbitrary three-dimensional (3-D) monochromatic light field are determined in terms of the geometrical parameters of the 3-D vibration of the time-harmonic electric field. In three dimensions, there are as many distinct linear polarization states as there are points on the surface of a hemisphere, and the number of distinct 3-D circular polarization states equals that of all two-dimensional (2-D) polarization states on the Poincaré sphere, of which only two are circular states. The subset of 3-D polarization states that results from the superposition of three mutually orthogonal x, y, and z field components of equal amplitude is considered as a function of their relative phases. Interesting contours of equal ellipticity and equal inclination of the normal to the polarization ellipse with respect to the x axis are obtained in 2-D phase space. Finally, the 3×3 generalized Jones calculus, in which elastic scattering (e.g., by a nano-object in the near field) is characterized by the 3-D linear transformation E(s)=T E(i), is briefly introduced. In such a matrix transformation, E(i) and E(s) are the 3×1 GJVs of the incident and scattered waves and T is the 3×3 generalized Jones matrix of the scatterer at a given frequency and for given directions of incidence and scattering.     

Simultaneous Determination of 23 Azo Dyes in Paprika by Gas Chromatography-Mass Spectrometry

The present work describes the development and validation of a simple, quick and precise gas chromatography-mass spectrometry (GC-MS) method for the analysis of 23 azo dye breakdown products in paprika samples. After the extraction procedure, dyes were identified on an Agilent J&W DB-5ms Ultra Inert capillary column using dichloroethane as a sample dissolvent. Limits of detection (LODs) were comprised between 10.6 and 84.4 ng/mL. Accuracy values in the range of 90–104 % for the 23 azo dye breakdown products were obtained, and RSD% for the analysis of 2.4 μg/mL of each compound was below 4.6 % (n = 9). The recovery for the azo dyes in paprika samples was comprised between 71.2 ± 3.5 % (benzidine) and 118.9 ± 2.5 % (para-cresidine). Results of this study suggest that the developed method is suitable for detection and quantification of azo dye breakdown products in the range of 60–240 μg/kg paprika. In addition, this GC-MS method allowed the simultaneous determination of disperse orange 3 (azo dye) with high accuracy and precision. The method has numerous advantages such as simplicity, low cost, easy operation and short analysis time and constitutes an efficient method for the monitoring of a large number of azo dyes in food matrices.     

Thick glass film technology for polysilicon surface micromachining

This paper explores the use of thick glass films as suitable alternatives to CVD oxide films for use as sacrificial, planarization, and passivation layers in polysilicon surface micro-machining processes. Such glasses can be spin-coated to produce films up to 20 μm thick in one step and to globally planarize the wafer surface, extending the overall mechanical design capability by enabling additional device structural complexity. Glass optical constants were determined, and the film quality was evaluated using SEM, EDS, XPS, and XRD. The films were found to have low intrinsic stresses and other characteristics desirable for sacrificial layer applications. A glass chemical-mechanical polishing process with 5300~Å/min removal rate and acceptable selectivity to polysilicon was developed, along with a wet etch chemistry that preferentially etches the film at 3.24 μm/min without affecting the silicon substrate or the structural polysilicon. The film was used to planarize up to 10-μm-tall topographies associated with surface micromachined features through spin-on and polish-back steps, and was in addition demonstrated to be a viable protective layer for silicon wafers during extended KOH etching in silicon bulk micro-machining processes. The glass has stable constituents that do not diffuse or contaminate either the substrate or the device features during the application and firing procedures     

A rotary electrostatic micromotor 1×8 optical switch

This paper describes a 1×8 rotary electrostatic micromotor optical switch fabricated using high-aspect-ratio micromachining technology to produce silicon or nickel components which are subsequently assembled to form a switch. The switch consists of a salient-pole micromotor with 1-mm-diameter 200-μm-thick rotor that supports up to a 500-μm-tall, 900-μm-wide mirror. Typical switches were actuated at 50 V, operated for extended periods in room air, and found to have a rapid rotation with an average optical switching time between two neighboring fiber ports of 18 ms. Optical testing was performed at wavelength of 1310 nm in single- and multimode, and at 850 nm in multimode. The optical beam was propagated in free space with minimal divergence through the use of externally mounted collimating gradient-index lenses. With an aluminum coating, the mirror and external optics exhibited an input to output coupling loss as low as 0.96 dB in multimode and 2.32 dB in single-mode. Interchannel crosstalk was less than -45 dB     

Tricuspid valve surgery and intraoperative echocardiography: factors affecting survival, clinical outcome, and echocardiographic success

BACKGROUND: The impact of echocardiographic-guided treatment on outcome after tricuspid valve (TV) surgery is not well defined. OBJECTIVES: The purpose of this study was to determine clinical and echocardiographic factors associated with adverse outcomes after TV surgery and determine the role of intraoperative echo (IOE) in facilitating successful outcomes after TV surgery. METHODS: Four hundred and one patients (279 females, mean age 60 years) underwent TV surgery and other concomitant cardiac surgery at a single institution and were followed clinically and by echocardiography during a 10-year period. RESULTS: Decreased survival after TV surgery was associated with: preoperative increased New York Heart Association (NYHA) functional classification (relative risk [RR]=2.02), increased left ventricular dysfunction by echocardiography (RR=1.28), and use of a TV replacement strategy (RR=2.92). Decreased event-free survival after TV surgery was associated with concomitant coronary artery bypass grafting (RR=2.97). Late echocardiographic failure (3 to 4+ tricuspid valve regurgitation [TR]) after TV surgery was associated with increased severity of TR on preoperative echocardiogram (odds ratio [OR]=1.91). Decreased late echocardiographic failure after TV surgery was associated with the use of a TV annuloplasty ring with a repair strategy (OR=0.40). The surgical plan was altered at the time of surgery to insure a successful outcome in 32 (10%) of 335 patients based on IOE findings. CONCLUSIONS: Adverse outcomes after TV surgery can be predicted by several preoperative clinical and echocardiographic variables. IOE is useful in improving immediate, but not late, outcomes after TV surgery.