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Showing papers on "Tilt (optics) published in 1996"



Journal ArticleDOI
TL;DR: In this paper, a detailed theoretical treatment of the effects of grating tilt on the spectral characteristics of a tilted optical-fiber phase grating is presented, compared with experimentally measured spectra of strong gratings.
Abstract: A detailed theoretical treatment is presented of bound-mode to bound-mode Bragg reflection and bound-mode to radiation-mode coupling loss in a tilted optical-fiber phase grating. Numerical predictions of the effects of grating tilt on the spectral characteristics of such a grating are calculated. These predictions are compared with experimentally measured spectra of strong gratings written by ultraviolet irradiation of deuterium-sensitized fiber with grating tilt angles ranging from 0° to 15°. Good agreement is obtained between the theoretical predictions and the experimental results.

428 citations


Journal ArticleDOI
TL;DR: A simple and device-independent derivation of the relation between the angular dispersion and the pulse front tilt of short pulses is given in this article, and the obtained relation is also applicable when material dispersion is present.
Abstract: A simple and device-independent derivation of the relation between the angular dispersion and the pulse front tilt of short pulses is given. The obtained relation is also applicable when material dispersion is present.

192 citations


Patent
11 Sep 1996
TL;DR: In this article, a rotary member rotatably mounted on a distal end portion of an elongated catheter member of the probe and support thereon an ultrasound transducer consisting of a row of a large number of ultrasound elements was used for multi-plane electronic scan ultrasound.
Abstract: A multi-plane electronic scan ultrasound probe having a rotary member rotatably mounted on a distal end portion of an elongated catheter member of the probe and support thereon an ultrasound transducer consisting of a row of a large number of ultrasound elements. The rotary member is connected to a rotation control knob on a manipulating head of the probe by way of rotation transmission wires extended through the catheter member and via a drive pulley mounted on the manipulating head in association with the rotation control knob to turn the ultrasound transducer through an arbitrary angle in multi-plane electronic scanning by manipulation of the rotation control knob. In addition, for the purpose of tilting the ultrasound transducer through a desired angle, the ultrasound probe is provided with a tilting mechanism to tilt the rotational axis of the rotary member in a predetermined direction, including a tiltable support for the rotary member, a tilt control means provided on the manipulating head, and a tilt signal transmission means for transmitting a tilt control signal from the tilt control means to the tiltable support.

93 citations


Journal ArticleDOI
TL;DR: In this paper, the authors describe a digital shearing interferometer system composed of a Mach - Zehnder interferometers which allows us to split the image of one object and to recombine the two images shifted and tilted.
Abstract: In this paper we describe a digital shearing interferometer system. The set-up is composed of a Mach - Zehnder interferometer which allows us to split the image of one object and to recombine the two images shifted and tilted. The tilt between the two images is chosen in order to produce a carrier frequency. The spatial carrier phase-shifting method is used for the quantitative evaluation. Two separate shearograms of an object under test are recorded using a CCD-sensor and stored in a frame grabber. The phases of the two shearograms are calculated from the complex amplitudes and the gradient is obtained from the phase difference. Experimental results are presented.

92 citations



Journal ArticleDOI
TL;DR: Tilt difference introduces a length scale into the elastic theory of tilted fluid membranes and provides a simple mechanism for the spontaneous breaking of inversion symmetry seen in some recent experiments.
Abstract: Lipid bilayer membranes below their main transition have two tilt order parameters, corresponding to the two monolayers. These two tilts may be strongly coupled to membrane shape but only weakly coupled to each other. We discuss some implications of this observation for rippled and saddle phases, bilayer tubules, and bicontinuous phases. Tilt difference introduces a length scale into the elastic theory of tilted fluid membranes. It can drive an instability of the flat phase; it also provides a simple mechanism for the spontaneous breaking of inversion symmetry seen in some recent experiments.

69 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigate the expression of non-Kolmogorov turbulence in terms of Zernike polynomials and find that the variance depend more strongly on outer scale than on exponent and that longer outer scale lengths lead to more energy in the tilt terms.
Abstract: We investigate the expression of non-Kolmogorov turbulence in terms of Zernike polynomials. Increasing the power-law exponent of the three-dimensional phase power spectrum from 2 to 4 results in a higher proportion of wave-front energy being contained in the tilt components. Closed-form expressions are given for the variances of the Zernike coefficients in this range. For exponents greater than 4 a von Karman spectrum is used to compute the variances numerically as a function of exponent for different outer-scale lengths. We find in this range that the Zernike-coefficient variances depend more strongly on outer scale than on exponent and that longer outer-scale lengths lead to more energy in the tilt terms. The scaling of Zernike-coefficient variances with pupil diameter is an explicit function of the exponent.

65 citations


Journal ArticleDOI
TL;DR: In this article, the Tsyganenko 1989a model is compared with the ranges predicted for the same locations by the different Kp parameterizations of the magnetic field model as a function of local time and season.
Abstract: The range of magnetic field tilt angles observed at several satellites in geosynchronous orbit is compared with the ranges predicted for the same locations by the different Kp parameterizations of the Tsyganenko 1989a magnetic field model as a function of local time and season. The data are examined separately for satellite locations near the magnetic equator and slightly off the equator. The model predicts reasonably well the observed basic variation in the tilt angle with location, and it permits a range of field inclinations adequate to encompass the majority of the observed angles for the dawn, dusk, and night quadrants. On the day side of the magnetosphere the model exhibits very little variation in tilt over the entire range of parameterizations and cannot reproduce the observed range of tilt angles. Near the magnetic equator the majority of observed tilt angles lie within the model range, with roughly equal numbers of cases that are overstretched or understretched with respect to the model range. Off the equator the models tend to be more stretched than is generally observed. With some modest season-to-season differences these results are valid for all four seasons.

63 citations


Journal ArticleDOI
TL;DR: In this article, it was shown that tilt angle uctuations can arise in model calculations from interactions with hydrodynamic turbulence during the tube's rise, which is consistent with observations.
Abstract: Bipolar magnetic regions are believed to form when ux originating below the solar convection zone rises to the surface in the form of long thin loops. Numerical models of rising ux tubes have been able to explain many observed features of these bipoles, including their angle of tilt relative to the East-West direction. Observations reveal that the mean tilt angle, , varies with both latitude of emergence and with ux, in agreement with simulations. However, observed bipoles also exhibit a considerable uctuation, , about the mean tilt angle. Here we show that tilt angle uctuations can arise in model calculations from interactions with hydrodynamic turbulence during the tube's rise. Numerical simulations indicate that both the magnitude of these uctuations, and their scaling with footpoint separation ((d ?1) are consistent with observations. Best agreement with observations occurs for ux tubes whose magnetic eld strength is similar to those used in other numerical investigations, B 0 30 kG. Furthermore, the agreement with observation suggests that turbulent velocities throughout the convection zone are consistent with those derived from mixing length convection models.

61 citations


Journal ArticleDOI
TL;DR: A direct method for retrieval of the projected potential from a single HREM image of a thin sample is presented, and both out-of-focus and astigmatic images can be restored and a further improvement achieved by imposing the symmetry exactly.

Journal Article
TL;DR: In this article, the energy and structure of Σ3 tilt boundaries with (110) and (211) tilt axis in Cu are investigated. And the results of experimental and theoretical studies on the energy of these boundaries are presented.
Abstract: This article presents the results of experimental and theoretical studies on the energy and structure of Σ3 tilt boundaries with (110) and (211) tilt axis in Cu. For both types of boundaries, a plot of the grain boundary energy versus the inclination of the boundary plane features a minimum at high inclinations against the plane of the coherent twin boundary. Along with this second energy minimum, the boundaries exhibit complex, three-dimensional structures, featuring a thin slab along the boundary plane in which Cu adopts unusual crystal structures. In the (110) tilt boundaries the slab has a rhombohedral structure (9R), while in the (211) tilt boundaries it has a body-centered cubic structure. These structures seem to be energetically favorable because they continue close-packed layers of atoms across the grain boundary.

Patent
26 Dec 1996
TL;DR: A sun tracking system and method for tracking the position of the sun is described in this paper, which includes an on-board computer for controlling each device, a solar array driving unit for rotating the solar array and transmitting an array angle to the onboard computer, an array tilt mechanism for adjusting a tilt of the solar arrays and for transmitting an tilt angle to an onboard computer.
Abstract: A sun tracking system and method for tracking the position of the sun. The sun tracking system includes an on-board computer for controlling each device; a solar array driving unit for rotating a solar array and for transmitting an array angle to the on-board computer; an array tilt mechanism for adjusting a tilt of the solar array and for transmitting an tilt angle to the on-board computer; the solar array connected to the solar array driving unit and to the array tilt mechanism, for supplying a current and a voltage to a peak power tracker; and the peak power tracker for supplying a power generated from the solar array to each part of a satellite and for supplying a peak power to the on-board computer.

Patent
17 May 1996
TL;DR: In this paper, a projection exposure apparatus is described where a pattern formed on a mask is projected onto a substrate through a projection optical system, and an illumination optical system is used to illuminate the mask by exposure light.
Abstract: A projection exposure apparatus wherein a pattern formed on a mask is projected onto a substrate through a projection optical system. The apparatus has an illumination optical system for illuminating the mask by exposure light, and a first adjusting member which is disposed in the illumination optical system to change telecentricity on the substrate. The apparatus further has a second adjusting member for adjusting at least one of the position of the substrate in the direction of an optical axis of the projection optical system and the tilt of the substrate, and a control system for controlling the first and second adjusting members. The control system locally corrects the position of a spatial image formed by the projection optical system.


Journal ArticleDOI
TL;DR: A method is presented here for aligning tilt projections without the use of markers, utilizing correlation methods and has proven to be both accurate and reproducible for the data presented here.

Journal ArticleDOI
TL;DR: Biphasic shocks with 50% tilt required less energy for defibrillation than 40, 65%, and 80% tilts, and in the clinical setting a programmable tilt may be preferable to account for some patient‐to‐patient variability.
Abstract: OBJECTIVE The goal of this study was to assess if tilt bears any impact on defibrillation efficacy of biphasic shocks. BACKGROUND Although it has been shown that biphasic waveform may increase the defibrillation efficacy, this pulsing method has not been as extensively studied in patients, and information regarding the effect of different tilts is lacking. METHODS This study consisted of two similar but distinct protocols including 33 patients undergoing transvenous defibrillator implant. In 17 patients (Part I) defibrillation threshold was obtained delivering biphasic waveforms with 50%, 65%, and 80% tilt in random fashion. Similarly, in 16 patients (Part II) testing of biphasic waveform with 40%, 50%, and 65% tilt was performed in random order. The electrode system used consisted of two transvenous leads and a subcutaneous patch in all 33 patients. RESULTS In Part I, tilt of 50% demonstrated a defibrillation threshold significantly lower than 65% tilt (7.5 +/- 4.3 J vs 9.7 +/- 5.0 J; P = 0.04) and 80% tilt (7.5 +/- 4.3 J vs 11.7 +/- 5.9 J; P < 0.01). Similarly, 65% tilt provided a lower defibrillation threshold than 80% tilt (9.7 +/- 5.0 J vs 11.7 +/- 5.9 J; P = 0.02). In Part II, no significant difference was observed in terms of defibrillation threshold between 40% tilt and the two tilts of 50% and 65%. However, as in Part I, 50% tilt provided a significant reduction of the energy to defibrillate as compared to 65% tilt (6.3 +/- 3.6 J vs 9.0 +/- 4.8 J; P < 0.01). The 50% tilt resulted in better defibrillation efficacy than 65% tilt independent of the lead system used for testing (Medtronic Transvene and CPI Endotak-C). CONCLUSIONS Biphasic shocks with 50% tilt required less energy for defibrillation than 40%, 65%, and 80% tilts. However, in the clinical setting a programmable tilt may be preferable to account for some patient-to-patient variability.

Patent
12 Aug 1996
TL;DR: In this article, a support structure for attachment to a chair base to support a seat and a backrest is described, which includes a tilt mechanism operable by leaning on an associated backrest to bend a spring link.
Abstract: A support structure is provided for attachment to a chair base to support a seat and a backrest. The structure includes a tilt mechanism operable by leaning on an associated backrest to bend a spring link. As a result, both the backrest and seat tilt a predetermined amount. The disclosure also provides an embodiment in which the tilt mechanism is adjustable so that the user can vary the amount of tilt achieved by leaning on the backrest.

Patent
Haruna Kawashima1
23 Apr 1996
TL;DR: In this paper, a registration method is proposed for projecting first and second patterns of a first object simultaneously upon a second object having a surface step, where the first pattern has a smaller depth of focus than that of the second pattern.
Abstract: A registration method is usable with projection optical system for projecting first and second patterns of a first object simultaneously upon a second object having a surface step, for measuring at different locations the surface position of the second object with respect to the direction of an optical axis of the projection optical system prior to the pattern projection to bring the surface of the second object into coincidence with an image plane of the projection optical system on the basis of the measurement, wherein the first pattern has a smaller depth of focus than that of the second pattern. The method includes bringing the surface position of the second object, at the location whereat the first pattern is to be projected, into coincidence with the image plane of the projection optical system; and correcting any tilt of the surface of the second object with respect to the image plane of the projection optical system.

Journal ArticleDOI
TL;DR: In this article, a series of 116 consecutive patients with DV associated with infantile esotropia were examined according to a predetermined protocol between 1989 and 1994, each patient was examined for a manifest head tilt.
Abstract: Introduction: Dissociated vertical divergence (DVD) has been associated with manifest head tilts. Also, DVD has been described as demonstrating a characteristic response to forced head tilt by increasing the size of the DVD on contralateral tilt. Methods: A series of 116 consecutive patients with DVD associated with infantile esotropia were examined according to a predetermined protocol between 1989 and 1994. Each patient was examined for a manifest head tilt. Also, the response of the DVD to forced ipsilateral and contralateral head tilt was analyzed. In addition, 100 consecutive patients with manifest head tilts were examined and the etiology of the tilt determined. Results: A manifest head tilt was present in 35% (26/74) of patients with an ocular fixation preference and no prior vertical muscle surgery. None of the patients with alternating fixation and a history of no vertical muscle surgery manifested a head tilt. Most patients responded in the classically described manner by increasing the size of the DVD on forced contralateral tilt and decreasing the size of the DVD on ipsilateral tilt. Atypical responses were not related to the presence of oblique overaction. DVD was the etiology in 9 of 100 consecutive patients with a manifest head tilt. Conclusions: Patients with DVD often manifest a head tilt. Most respond by increasing the size of the DVD on forced contralateral head tilt and decreasing on ipsilateral tilt. Atypical responses did not appear to be influenced by oblique overaction. DVD is a relatively frequent cause of manifest head tilts.

01 Oct 1996
TL;DR: In this paper, an asymptotic expression for the vorticity field around a strong thin straight vortex tube of circulation, starting with a vortex filament in a simple shear flow (U = SX 2 Xˆ 1, S being a shear rate) is investigated analytically.
Abstract: The mechanism of wrap, tilt and stretch of vorticity lines around a strong thin straight vortex tube of circulation Γ starting with a vortex filament in a simple shear flow ( U = SX 2 Xˆ 1 , S being a shear rate) is investigated analytically. An asymptotic expression for the vorticity field is obtained at a large Reynolds number Γ/ ν [Gt ]1, ν being the kinematic viscosity of fluid, and during the initial time St [Lt ]1 of evolution as well as St [Lt ](Γ/ ν ) 1/2 . The vortex tube, which is inclined from the streamwise ( X 1 ) direction both in the vertical ( X 2 ) and spanwise ( X 3 ) directions, is tilted, stretched and diffused under the action of the uniform shear and viscosity. The simple shear vorticity is on the other hand, wrapped and stretched around the vortex tube by a swirling motion, induced by it to form double spiral vortex layers of high azimuthal vorticity of alternating sign. The magnitude of the azimuthal vorticity increases up to O ((Γ/ ν ) 1/3 S ) at distance r = O ((Γ/ ν ) 1/3 ( νt ) 1/2 ) from the vortex tube. The spirals induce axial flows of the same spiral shape with alternate sign in adjacent spirals which in turn tilt the simple shear vorticity toward the axial direction. As a result, the vorticity lines wind helically around the vortex tube accompanied by conversion of vorticity of the simple shear to the axial direction. The axial vorticity increases in time as S 2 t , the direction of which is opposite to that of the vortex tube at r = O ((Γ/ ν ) 1/2 ( νt ) 1/2 ) where the vorticity magnitude is strongest. In the near region r [Lt ](Γ/ ν ) 1/3 ( νt ) 1/2 , on the other hand, a viscous cancellation takes place in tightly wrapped vorticity of alternate sign, which leads to the disappearance of the vorticity normal to the vortex tube. Only the axial component of the simple shear vorticity is left there, which is stretched by the simple shear flow itself. As a consequence, the vortex tube inclined toward the direction of the simple shear vorticity (a cyclonic vortex) is intensified, while the one oriented in the opposite direction (an anticyclonic vortex) is weakened. The growth rate of vorticity due to this effect attains a maximum (or minimum) value of ± S 2 /3 3/2 when the vortex tube is oriented in the direction of Xˆ 1 + Xˆ 2 ∓ Xˆ 3 . The present asymptotic solutions are expected to be closely related to the flow structures around intense vortex tubes observed in various kinds of turbulence such as helical winding of vorticity lines around a vortex tube, the dominance of cyclonic vortex tubes, the appearance of opposite-signed vorticity around streamwise vortices and a zig-zag arrangement of streamwise vortices in homogeneous isotropic turbulence, homogeneous shear turbulence and near-wall turbulence.

Patent
Kenichi Miyazawa1, Noboru Ishii1
26 Nov 1996
TL;DR: In this article, a display device includes a display portion and a tilt mechanism, which can be rotated around a rotation center and the display device can be installed on and removed from an external device such as a keyboard, bar code reader and a POS terminal.
Abstract: A display device includes a display portion and a tilt mechanism The tilt mechanism can be rotated around a rotation center and the display device can be installed on and removed from an external device such as a keyboard, bar code reader and a POS terminal The display device may include a fixing member, used for fixing the display device to the external device, provided with the tilt mechanism

Patent
15 Mar 1996
TL;DR: In this article, a variator for a continuously variable-ratio transmission (CVT) of the half-toroidal traction roller type is presented, in which a ratio change results when a roller exercises a first freedom of movement by rotating about a first or precession axis.
Abstract: A variator for a continuously-variable-ratio transmission (CVT) of the half-toroidal traction roller type in which a ratio change results when a roller exercises a first freedom of movement by rotating about a first or precession axis. In addition, the roller mounting has a further freedom of movement about a second or tilt axis. The precession axis is inclined at an angle ("the castor angle") to a plane lying normal to the axis of the races and each equilibrium value of the ratio angle correlates with a unique angular orientation of the roller about the tilt axis.

Journal ArticleDOI
TL;DR: The results suggest that roll tilt to the right and to the left is sensed by two independent functional units and that the perceptual horizontal in the upright position and tilt perception are complementary in reflecting vestibular function.

Journal Article
TL;DR: In this article, the absolute determination of the tip tilt can be inferred from two artiicial laser beacons in the high atmosphere (e.g. in the Sodium layer) generated from two ground stations located away from the observing place.
Abstract: abstract It is shown that the absolute determination of the tip{tilt can be inferred from two artiicial laser beacons in the high atmosphere (e.g. in the Sodium layer) generated from two ground stations located away from the observing place. The technique is limited by the required Field of View for such a telescope. Assuming a retro{{t to existing telescopes, the technique is feasible only for small (D 4m) telescopes in very good seeing conditions (r 0 = 0:20m). The applicability to largest telescopes or worst seeing condition is possible in some cases with a dedicated telescope's optics.

Patent
Hyun-Woo Lee1
19 Jul 1996
TL;DR: A pickup position and tilt adjusting apparatus of an optical disk player includes at least one guide rail installed on a deck for supporting and guiding a pickup as discussed by the authors, as well as a position adjusting unit for horizontally moving one end of the guide rail with respect to a disk surface.
Abstract: A pickup position and tilt adjusting apparatus of an optical disk player includes at least one guide rail installed on a deck for supporting and guiding a pickup, at least one position adjusting unit for horizontally moving one end of the guide rail with respect to a disk surface, and at least one tilt adjusting unit for vertically moving the other end of the guide rail with respect to the disk surface.

Patent
28 Oct 1996
TL;DR: An optical disc driving device employing an optical disc as a recording medium is described in this article.The device includes a skew control mechanism for controlling relative tilt between a single optical disc and an objective lens for selectively recording and/or reproducing data on or from a first optical disc having a standard recoding density and a second one having a high recording density.
Abstract: An optical disc driving device employing an optical disc as a recording medium. The device includes a skew control mechanism for controlling relative tilt between an optical disc and an objective lens for selectively recording and/or reproducing data on or from a first optical disc having a standard recoding density and a second optical disc having a high recording density. The relative tilt between the second optical disc and the objective lens is controlled by the skew control mechanism only when the second optical disc is loaded and data is recorded and/or reproduced on or from the second optical disc.

Proceedings ArticleDOI
05 Feb 1996
TL;DR: In this paper, the expression of non-Kolmogorov turbulence in terms of Zernike polynomials was investigated in the three-dimensional phase power spectrum.
Abstract: We investigate the expression of non-Kolmogorov turbulence in terms of Zernike polynomials. Increasing the power-law exponent of the three-dimensional phase power spectrum from 2 to 4 results in a higher proportion of wavefront energy being contained in the tilt components. Closed-form expressions are given for the variances of the Zernike coefficients in this range. For exponents greater than 4, a von Karman spectrum is used to numerically compute the variances as a function of exponent for different outer-scale lengths. We find in this range that the Zernike-coefficient variances depend more strongly on outer scale than on exponent, and that longer outer-scale lengths lead to more energy in the tilt terms. The scaling of Zernike- coefficient variances with pupil diameter is an explicit function of the exponent.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.


Journal ArticleDOI
TL;DR: Spots on the plates that gave non-Airy-function line shapes over the entire order of interference were found, unlike the Airy line shape the authors determined previously by using the entire 8-mm aperture.
Abstract: While investigating the instrumental function of a Fabry–Perot interferometer [Appl. Opt. 34, 58 (1995)], we noticed some variation in finesse and contrast in the measured spectra when a 1.5-mm-diameter aperture was used at various spots within the standard 8-mm aperture. By comparing experimentally determined finesse versus contrast plots for many such spectra with calculated plots, we found spots on the plates that gave non-Airy-function line shapes over the entire order of interference, unlike the Airy line shape we determined previously by using the entire 8-mm aperture. We have reviewed several models that describe the effects of various types of surface defects, such as Gaussian-height distribution of roughness, curvature and tilt of plates, sinusoidal roughness, and asymmetrical roughness on the finesse and contrast. Our experimental results can be accounted for if we assume that the reflectivity is nonuniform over the Fabry–Perot plates and that there is some reasonable contribution that is due to Gaussian roughness, curvature, or tilt.