Splay Angle Research Articles

Platinum bisphosphine complexes of 1,8-naphthosultone

A series of three platinum(II) bisphosphine complexes 1–3 [Pt(1-(SO2),8-(O)-nap)(PR3)2] (where R3=Ph3, Ph2Me, Me2Ph) have been prepared by metathesis from cis-[Pt(PR3)2Cl2)] and the dilithium salt of 1,8-naphthosultone. The novel compounds were fully characterised by X-ray crystallography, multinuclear NMR, IR and MS. The molecular structures of 1–3 were compared by measuring the peri-distance, splay angle magnitude, peri-atom displacement, naphthalene ring torsions, aromatic ring orientations and the geometry around the platinum centre. The platinum metal adopts a distorted square planar geometry in all three complexes which causes deformation of the naphthalene system. The degree of molecular deformation does not decrease upon going from 1 to 3 as anticipated, instead a competition between steric effects and intramolecular interactions causes 3 to display distortion intermediate of 1 and 2.

Platinum Complexes of 5,6‐Dihydroacenaphtho[5,6‐cd]‐1,2‐dichalcogenoles

AbstractSix bis(phosphane)platinum complexes bearing dichalcogen acenaphthene ligands have been prepared by metathesis from cis‐[PtCl2(PR3)2] (R3 = Ph3, Ph2Me, PhMe2) and the dilithium salts of the parent 5,6‐dihydroacenaphtho[5,6‐cd]‐1,2‐dichalcogenoles (AcenapE2, L1 E = S, L2 E = Se). For their synthesis, the appropriate disulfide or diselenide species was treated with super hydride [LiBEt3H] to afford the dilithium salt by in situ reduction of the AcenapE2 E–E bond. Further reaction, by metathetical addition to the cis‐platinum precursor afforded the respective platinum(II) complexes [Pt(5,6‐AcenapE2)(PR3)2] (R3 = Ph3: E = S 1, Se 2; R3 = Ph2Me: E = S 3, Se 4; R3 = PhMe2: E = S 5, Se 6). All six complexes have been fully characterised, principally by multinuclear magnetic resonance spectroscopy, IR spectroscopy and MS. The selenium complexes 4 and 6 provide examples of AA′X spin systems, as displayed by their 31P{1H} NMR spectra. The X‐ray structures of L1, L2, 1, 2, 5 and 6 were determined and, where appropriate, the platinum metal geometry, peri‐atom displacement, splay angle magnitude, acenaphthene ring torsion angles and E···E interactions were analysed. The platinum atoms were found to adopt a distorted square‐planar geometry in all four complexes, and the nature of the AcenapE2 ligand plays little part in the conformation of the substituents bound to the trivalent phosphorus atoms.

The effect of thickness and substrate tilt on the BZO splay and superconducting properties ofYBa2Cu3O7 − δ films

Highly splayed BaZrO3 nanorods (BZO-NRs) were generated inYBa2Cu3O7 − δ (YBCO) films dopedwith 2 vol% BZO on 5° vicinal SrTiO3 (STO) substrates. It was observed that the splay angle of the BZO-NRs around thec-axis increases with film thickness from about10° at 0.2 µm to35°–40° at1 µm. Although the same trend was observed in BZO-NRs in flat YBCO films, the splayangle at a given thickness and its increase with film thickness are significantlysmaller. The enhanced dispersion of BZO-NRs in vicinal YBCO/BZO-NR filmsresults in a much reduced strain on the YBCO lattice as compared to its flatcounterpart. This led to less disturbed normal-state electron conduction along theab-plane, higherTc values andenhanced Jc values due to improved magnetic pinning.

Relative contributions of optic flow, bearing, and splay angle information to lane keeping

Heading from optic flow, bearing, and splay angle information can all be used for lane keeping on a straight path. Here we investigated the relative contributions of these three visual cues to accurate lane-keeping control in a novel way. The displays simulated observers steering a vehicle down a straight path defined by a pair of posts (providing bearing angles only) or a segment of lane edges (providing bearing and splay angles) at a fixed viewing distance, and the ground contained no flow, sparse flow, or dense flow. Observers used a joystick to control the vehicle's lateral movement to stay in the center of the lane while facing random perturbations to both the vehicle's lateral position and orientation. The lateral position perturbation affected the use of both splay and bearing angle cues, but the vehicle orientation perturbation only affected the use of bearing angles. We found that performance improved as more flow information was added to the scene regardless of the availability of bearing or splay angle information. In the presence of splay angles, observers would ignore bearing and rely mainly on splay angles for lane keeping.

Synthetic and Structural Studies of 1,8‐Chalcogen Naphthalene Derivatives

Four novel 1,8-disubstituted naphthalene derivatives 4-7 that contain chalcogen atoms occupying the peri positions have been prepared and fully characterised by using X-ray crystallography, multinuclear NMR spectroscopy, IR spectroscopy and MS. Molecular distortion due to noncovalent substituent interactions was studied as a function of the bulk of the interacting chalcogen atoms and the size and nature of the alkyl group attached to them. X-ray data for 4-7 was compared to the series of known 1,8-bis(phenylchalcogeno)naphthalenes 1-3, which were themselves prepared from novel synthetic routes. A general increase in the E...E' distance was observed for molecules containing bulkier atoms at the peri positions. The decreased S...S distance from phenyl-1 and ethyl-4 analogues is ascribed to a weaker chalcogen lone pair-lone pair repulsion acting in the ethyl analogue due to the presence of two equatorial S(naphthyl) ring conformations. Two novel peri-substituted naphthalene sulfoxides of 1, Nap(O=SPh)(SPh) 8 and Nap(O=SPh)(2) 9, which contain different valence states of sulfur, were prepared and fully characterised by using X-ray crystallography and multinuclear NMR spectroscopy, IR spectroscopy and MS. Molecular structures were analysed by using naphthalene ring torsions, peri-atom displacement, splay angle magnitude, S...S interactions, aromatic ring orientations and quasi-linear O=S...S arrangements. The axial S(naphthyl) rings in 8 and 9 are unfavourable for S...S contacts due to stronger chalcogen lone pair-lone pair repulsion. Although quasi-linear O=S...S alignments suggest attractive interaction is conceivable, analysis of the B3LYP wavefunctions affords no evidence for direct bonding interactions between the S atoms.

Sterically Crowded peri‐Substituted Naphthalene Phosphines and their PV Derivatives

Three sterically crowded peri-substituted naphthalene phosphines, Nap[PPh(2)][ER] (Nap=naphthalene-1,8-diyl; ER=SEt, SPh, SePh) 1-3, which contain phosphorus and chalcogen functional groups at the peri positions have been prepared. Each phosphine reacts to form a complete series of P(V) chalcogenides Nap[P(E')(Ph(2))(ER)] (E'=O, S, Se). The novel compounds were fully characterised by using X-ray crystallography and multinuclear NMR spectroscopy, IR spectroscopy and MS. X-ray data for 1, 2, nO, nS, nSe (n=1-3) are compared. Eleven molecular structures have been analysed by naphthalene ring torsions, peri-atom displacement, splay angle magnitude, X...E interactions, aromatic ring orientations and quasi-linear arrangements. An increase in the congestion of the peri region following the introduction of heavy chalcogen atoms is accompanied by a general increase in naphthalene distortion. P...E distances increase for molecules that contain bulkier atoms at the peri positions and also when larger chalcogen atoms are bound to phosphorus. The chalcogenides adopt similar conformations that contain a quasi-linear E...P-C fragment, except for 3O, which displays a twist-axial-twist conformation resulting in the formation of a linear O...Se-C alignment. Ab initio MO calculations performed on 2O, 3O, 3S and 3Se reveal Wiberg bond index values of 0.02 to 0.04, which indicates only minor non-bonded interactions; however, calculations on radical cations of 3O, 3S and 3Se reveal increased values (0.14-0.19).

Synthetic and Structural Studies of 1-Halo-8-(alkylchalcogeno)naphthalene Derivatives

A series of eight 1-halo-8-(alkylchalcogeno)naphthalene derivatives (1-8; halogen=Br, I; alkylchalcogen=SEt, SPh, SePh, TePh) containing a halogen and a chalcogen atom occupying the peri positions have been prepared and fully characterised by using X-ray crystallography, multinuclear NMR spectroscopy, IR spectroscopy and MS. Naphthalene distortion due to non-covalent substituent interactions was studied as a function of the bulk of the interacting chalcogen atoms and the size and nature of the alkyl group attached to them. X-ray data for 1, 2, 4 and 5-8 were compared. Molecular structures were analysed in terms of naphthalene ring torsions, peri-atom displacement, splay angle magnitude, X...E interactions, aromatic ring orientations and quasi-linear X...E-C arrangements. A general increase in the X...E distance was observed for molecules that contain bulkier atoms at the peri positions. The I...S distance of 4 is comparable with the I...Te distance of 8, and is ascribed to a stronger lone pair-lone pair repulsion due to the presence of an axial S(naphthyl) ring conformation. Density functional theory (B3LYP) calculations performed on 5-8 revealed Wiberg bond index values of 0.05-0.08, which indicate minor interactions taking place between the non-bonded atoms in these compounds.

Active control of lane keeping uses optic flow, bearing, and splay angle information

Previous studies have shown that people rely mainly on splay angle (the optical angle of the lane markers with respect to the vertical in the image plane) for lane keeping during driving (e.g., Beall & Loomis, Perception, 1996). Here we investigate whether optic flow and bearing also contribute to the control of lane keeping. The display (110° H × 94° V) simulated an observer steering a vehicle down a straight path at 3 m/s under three conditions: (a) an empty ground with lane markers providing bearing and splay angle information; (b) a random-dot ground with lane markers providing bearing, splay angle, and sparse optic flow information, and (c) a textured ground with lane markers providing bearing, splay angle, and dense optic flow information. Participants used a joystick to control the vehicle's lateral velocity to stay at the center of the lane while the vehicle's lateral position was perturbed by the sum of seven non-harmonic sinusoids (0.1 to 2.19 Hz). For 11 participants (9 na?ve), the vehicle's lateral deviation from the center of the lane, indicated by the RMS error, was larger for the empty ground (mean±SE: 0.39±0.02 m) than for the random-dot and the textured ground display (0.37±0.02 m in both cases), indicating the influence of optic flow on lane keeping. We then varied the optical gain of bearing in the display by providing lane markers (3.1± V) at three distances (3.2 m, 7.8 m, & 22.2 m). For eight participants (7 naïve), the RMS error increased with the distance for the empty ground but not for the random-dot or the textured ground display, indicating that bearing information helps lane keeping in the absence of optic flow information. We conclude that optic flow, bearing, and splay angle all contribute to accurate lane keeping.

Synthesis and structural study of (8-phenylsulfanylnaphth-1-yl)diphenylphosphine metal complexes

A series of three platinum(II) halide complexes 2– 4 [Pt(X) 2{Nap(PPh 2)(SPh)}] (Nap = naphthalene-1,8-diyl; X = Cl, Br, I) and a ruthenium(II) p-cymene complex 5 [Ru( η 6-MeC 6H 4 i Pr)(Cl){Nap(PPh 2)(SPh)}] +Cl − of the sterically crowded peri-substituted naphthalene phosphine 1 have been prepared. The compounds were fully characterised by multinuclear NMR, IR and MS and X-ray data for 1– 5 are compared. Molecular structures are analysed by naphthalene ring torsions, peri-atom displacement, splay angle magnitude, P···S interactions, aromatic ring orientations and geometry around the metal centre. Platinum adopts a strictly square planar geometry which increases the distortion of the naphthalene skeleton in 2– 4. Conversely, the classical-piano stool conformation of 5 results in a pseudo-octahedral conformation around the ruthenium atom which influences the naphthalene geometry to a much lesser extent with distortion of a similar magnitude to the free ligand 1.

Loudspeaker rigging system having contained maneuverable connecting links

A side frame for a loudspeaker rigging system has a frame structure mountable to the side of a loudspeaker, and links associated with the frame structure for linking together the corners of the frame structures of vertically adjacent side frames. The links associated with each side frame structure include a pivot link and splay adjustment link, each of which has a top extended end and a base end. Stow channels, which are preferably located in the bottom corner regions of the frame structure, contain the pivot link and splay adjustment link in the frame structure. A gripping structure associated with at least one, and preferably each link of the pivot and splay adjustment links allows a user to easily maneuver a link from its stowed to its deployed position. The extended end of the splay adjustment link includes at least two, and preferably an array of pin holes which can selectively be matched with one pin hole within a row of pin holes in a bottom corner region of the side frame to permit adjustments of the splay angle over a range of angles. Suitably, two rows of pin holes are provided in the top extended end of the splay adjustment link to permit multiple and incrementally small splay angle adjustments. In the preferred embodiment, the frame structure is comprised of an assembly of parts comprised of a center core structure sandwiched between two side plates.

Quantifying Natural Fault Geometry: Statistics of Splay Fault Angles

Abstract We propose a new approach to quantifying fault system geometry, using an objective fit of the fault geometry to a test function, specifically here a fault branch. Fitting a Y-shaped object using a cost function to dextral faults in California, we find a number of significant results arising from use of a a systematic, objective, quantitative approach. (1) The largest angle of the branch structure is generally very close to 180°, implying that the branch is a splay fault off the primary through-going fault. (2) The distribution of the smallest angle, the splay angle, has a peak near ±17°, symmetric about the primary fault. (3) These features appear independent of scale. These results are not yet explained by any theory, and they pose new questions and constraints for the physics of fault system formation and behavior.

Convertible folded horn enclosure

A low frequency exponential bass horn enclosure employing a large area unitary throat pathway, bifurcated at a substantially parabolic rearward channel wall, convertible to a front-loaded or rear-loaded configuration by the use of interchangeable parts, with driver access from the front. Intended for corner placement, however, fully enclosed horn channel allows for floor use. The axially-centered throat expands vertically, exhausts rearward, and is bifurcated at the back of the enclosure with two hard reflection points, comprising a single fold, in which the vertically arranged horn terminus exhausts with a forward-canted splay angle around a partially rectangular back chamber.

2D vs. 3D Visual Cues for Altitude Maintenance in Low-Altitude Flight

Previous research on altitude maintenance in low-altitude flight has focused either on cues provided by 2D features in the visual scene (e.g., splay angle) or on visual cues provided by the presence of 3D objects in the scene (e.g., occlusion). Therefore, little is known about the relative importance of 2D and 3D cues in altitude maintenance. We systematically varied the position variability, height, and pattern of surface elements in a simulated low-level flight environment to vary the salience of 2D and 3D visual cues. For 2D objects, altitude variability increased as a function of object position variability indicating that splay and depression angles are not reliable cues for terrains with irregularly spaced objects. For 3D objects, altitude variability increased less (or not at all) as a function of position variability indicating that the cues provided by 3D objects such as occlusion and motion parallax are the dominant visual cues for altitude maintenance for natural terrains with irregularly spaced objects.

Dynamic Behaviors of Directors in a Liquid Crystal Microlens

A numerical simulation of the temporal evolution and spatial distribution of directors in a liquid crystal microlens with a hole-patterned electrode structure is given. We show that both splay and twist deformation initially start at the hole boundary, and at each side of the hole center in the rubbing direction the splay angle is opposite and the twist rotation at neighboring quadrant is in opposite direction

The Splay Angle: A New Measure for Assessing Neuromuscular Dysfunction in Rats

This report describes a new method, the splay angle measures, to determine neuromuscular dysfunction. Splay angles are measured from a standard splay test and define hind limb orientation quantified, in degrees, by the paw strike of the hind limbs. We used mutant rats, presenting with a chronic central nervous system demyelinating disease, characterized by tremor, ataxia, immobility, epilepsy, and paralysis ( taiep). Significant differences between taiep ( n = 12) and normal control rats ( n = 10) were found for Linear Splay, AngleLeft, AngleRight, and AngleBoth. These results suggest that the splay angles are a sensitive measure of hind limb orientation and may reflect an underlying pathology.

Improving Safety and Aesthetic Results in Inverted T Scar Breast Reduction

Breast reduction using an inverted T scar skin design and a variety of glandular pedicle types is widely practiced and is the standard by which more recent limited scar techniques are judged. The inverted T procedures are attractive because they are predictable and versatile and permit great control over both the extent of reduction and the breast-shaping process. Despite these advantages, common criticisms of inverted T scar techniques include breast shape abnormalities, areolar malposition, hypertrophic scars, and poor long-term projection. Preoperative markings influence both safety and aesthetics. A method of skin marking that is based on a displacement method to determine vertical limb splay angle is described. This design concept must be modified to address certain variants, such as macromastia presenting with normal nipple position or large-diameter areolae, moderately severe macromastia, and macromastia involving radiated breasts. Safety in breast reduction is improved by paying attention to patient positioning issues, using techniques that minimize blood loss, raising flaps of appropriate thickness in the correct plane, and performing resection by observing the principles that reduce the risk of compromise of nipple and areolar circulation. Aesthetic results are improved by analyzing vertical breast meridian lengths during final breast shaping, modifying areolar shape as necessary, and carefully tailoring the medial inframammary crease. The latter is also important for minimizing the potential for scar hypertrophy. The principles presented have been refined during the course of a 12-year experience with several hundred breast reduction procedures. They contribute to improved results in inverted T scar breast reduction when practiced consistently.

Angular variation of pinning near the irreversibility temperature in single crystal Y Ba 2Cu 3O 7− δ with splayed columnar defects

We have studied vortex pinning through ac susceptibility measurements in single crystals of YBCO with columnar defects (CDs). The CDs have 0°, 10° and 20° splay angle and average direction 10° off the c-axis. By studying the angular variation we can compensate for the anisotropy and effects of twins, etc. Using a simple expression we can obtain the angular spread when the field direction is outside the splay angle. An increase of pinning when the field direction is inside the angle defined by the CDs can be attributed to vortex entanglement due to the splay and the suppression of the sliding of double kinks.

Voltage splay modes and enhanced phase locking in a modified linear Josephson array

We analyze a modified linear Josephson-junction array in which additional unbiased junctions are used to greatly enhance phase locking. This geometry exhibits strong correlated behavior, with an external magnetic field tuning the voltage splay angle between adjacent Josephson oscillators. The array displays a coherent in-phase mode for f=(1)/(2), where f is the magnetic frustration, while for 0{lt}f{lt}(1)/(2), a voltage wave propagates along the array with a phase velocity v{sub p}(f)=2aV{sub dc}/{Phi}{sub 0}(1{minus}2f). The locked splay modes are found to be tolerant of critical current disorder approaching 100{percent}. The stability of the array has also been studied by computing Floquet exponents. These exponents are found to be negative for all array lengths, with a 1/N{sup 2} dependence, N being the number of series-connected junctions. {copyright} {ital 1996} {ital The American Physical Society}

Enhanced pinning with controlled splay configurations of columnar defects: rapid vortex motion at large angles.

Orders-of-magnitude enhancements of persistent currents J are reported in $\mathrm{YBa}{}_{2}{\mathrm{Cu}}_{3}\mathrm{O}{}_{7\ensuremath{-}\ensuremath{\delta}}$ with columnar defects arranged in a variety of splayed configurations. The largest J is obtained for a planar distribution ${P}_{\mathrm{pl}}(\ensuremath{\Theta})$, with a splay angle ${\ensuremath{\Theta}}_{\mathrm{opt}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ifmmode\pm\else\textpm\fi{}5\ifmmode^\circ\else\textdegree\fi{}$. A comparison of ${P}_{\mathrm{pl}}(\ensuremath{\Theta})$ and a Gaussian distribution ${P}_{\mathrm{G}}(\ensuremath{\Theta})$ suggests that pinning by the latter is controlled by large-angle tails of the Gaussian which appear to enhance thermal creep rate. Numerical simulations confirm the existence of the regimes where vortex motion is promoted rather than suppressed by splay.

Visual control of steering without course information.

An analysis and experimental evidence are presented that the visual control of steering in following a straight demarcated path is possible even when information about the direction of one's travel (course) is not available. Two likely sources of optical information available to observers are considered, bearing and splay, that might be used for steering under these conditions. In an experiment involving a computer-driven driving simulator, observers attempted to steer a straight path while subjected to lateral perturbing forces. When only bearing and its time derivative, motion parallax, were available, performance fell off as expected with the optical gain of motion parallax as the preview distance of the viewing aperture was varied. When splay angle and its time derivative, splay rate, were added to the display, performance generally improved and remained relatively constant with changing distance of the viewing aperture, as expected because of the constant optical gain of splay rate. Making course information available by adding point features to both displays improved steering performance only in the motion-parallax conditions.