Local dimming algorithm and color gamut calibration for RGB LED backlight LCD display

A 32 in RGB LED backlight unit is developed. A local dimming algorithm is designed for the backlight, and grid-noise artifacts in the LC driving signal are successfully removed with consideration of the backlight distribution to provide identical intensity from each LED block. The 32 in RGB LED backlight LCD display has achieved a static display contrast of over 20000:1 and an average power reduction of 30%. We have also obtained the color gamut transformation matrix for transferring a cold cathode fluorescent lamp BLU LCD display gamut system to our RGB LED BLU LCD display gamut system, and extended the color saturation by suppositional color expansion method. As a result, the color has been accurately reproduced in RGB LED BLU LCD display with more richness and more saturation.     

Electro-optic mapping systems of electric-field using CW laser diodes

Two novel systems are proposed to perform the electro-optic (EO) mapping of the electric-field strength close to electrode structure using CW laser diodes. By these systems, mappings of both static (DC) and high-frequency electric-field can be obtained. For the static field, the field is chopped to increase the sensitivity performance. For the high-frequency field, an intensity modulation laser, instead of a pulse laser, is used to perform the mapping measurement in frequency domain, instead of in time domain. This approach greatly simplifies the system. An experiment set-up using a vertical cavity surface emitted laser diode (VCSEL) of a wavelength 850 nm and its mapping results for a coplanar waveguide (CPW) with the signal frequency around 1 GHz are reported.     

Improved direct measurement of the parity-violation parameter Ab using a mass tag and momentum-weighted track charge

We present an improved direct measurement of the parity-violation parameter A(b) in the Z boson-b-quark coupling using a self-calibrating track-charge technique applied to a sample enriched in Z-->bb events via the topological reconstruction of the B hadron mass. Manipulation of the Stanford Linear Collider electron-beam polarization permits the measurement of A(b) to be made independently of other Z-pole coupling parameters. From the 1996-1998 sample of 400,000 hadronic Z decays, produced with an average beam polarization of 73.4%, we find A(b)=0.906+/-0.022(stat)+/-0.023(syst).     

Variations in the Concentrations of Cu and Zn and in the Ratio of Cu to Zn in Whole Blood and Hair Samples from Hepatocellular Carcinoma Patients and from Healthy Controls in Taiwan

An atomic absorption spectrophotometer was used to determine concentrations of copper and zinc and the ratio of Cu to Zn in samples of whole blood and hair from hepatocellular carcinoma (HCC) patients (n=51) and from healthy controls (n=50) in Taiwan. Our results indicate that the HCC patients have higher copper concentrations and higher ratios of Cu to Zn than do the healthy controls both in whole blood and hair samples, but only the concentration of copper and the ratio of Cu to Zn in whole blood were significantly different (p<0.001 and p<0.05). Conversely, a lower concentration of zinc was found in whole blood and hair samples of HCC patients. Similarly, only the concentration of zinc in whole blood showed a significant difference (p<0.001). We concluded that the whole blood concentrations of copper and zinc and the ratio of Cu to Zn seemed to have a higher correlation with HCC. Thus, we suggest that a sample of whole blood may be a more suitable diagnostic sample than is a hair sample for HCC.     

First-Principle Calculations of the Adsorption, Dissociation and Diffusion of Hydrogen on the Mg(0001) Surface

First-principle pseudopotential plane wave calculations and the Nudged Elastic Band method based on density functional theory (DFT) have been used in this article to study the dissociation of molecular hydrogen on a Mg(0001) surface and the subsequent diffusion of atomic hydrogen into the magnesium substrate. First, the dissociation pathway of H2 and the relative barrier were investigated. It was shown that physical adsorption rather than chemisorption of molecular hydrogen was observed in the calculation of the dissociation process of molecular hydrogen. Also, the diffusion process of atomic hydrogen on Mg(0001) was presented. The surface effect, which affected the diffusion of hydrogen obviously, was observed. Finally, comparing the values of the activation energies for the steps of dissociation, diffusion, and desorption, our calculation further showed that the dissociation of H2 and the desorption of hydride were the rate-limiting steps.     

Observation of no significant surface enhancement of Raman scattering from benzoic acid molecules on mercury

There is controversy regarding the surface enhancement of Raman scattering due to liquid Hg, and the enhancement of benzoic acid molecules adsorbed on liquid Hg has been determined to be essentially zero. However, if the noise error bar is taken into account, the maximum enhancement is estimated to be less than 30. The same enhancement was observed when the temperature was reduced in solidifying liquid Hg.     

Direct measurement of decoherence for entanglement between a photon and stored atomic excitation

Violations of a Bell inequality are reported for an experiment where one of two entangled qubits is stored in a collective atomic memory for a user-defined time delay. The atomic qubit is found to preserve the violation of a Bell inequality for storage times up to 21 micros, 700 times longer than the duration of the excitation pulse that creates the entanglement. To address the question of the security of entanglement-based cryptography implemented with this system, an investigation of the Bell violation as a function of the cross correlation between the generated nonclassical fields is reported, with saturation of the violation close to the maximum value allowed by quantum mechanics.     

Boundary effects on granular shear flows of smooth disks

Summary We obtain boundary conditions for two-dimensional flows of identical, nearly elastic, circular disks that interact with a flat wall to which identical, evenly spaced half-disks have been attached. Expressions for the transfer of momentum and energy from the boundary to the flow are obtained by statistical averaging over all possible wall-flow disk collisions. We improve upon the expressions derived by Jenkins and Richman [1986] by employing in the averaging process a more elaborate velocity distribution function obtained through the method of moments. In addition we expand the distribution function about a point near the flat wall that guarantees positive slip velocities. With these boundary conditions, we analyze a two-dimensional shear flow driven by parallel bumpy boundaries. The constitutive theory employed includes both the effects of particle collisions and particle transport on the transfer of momentum and energy throughout the flow. We demonstrate how the resulting profiles of velocity, granular temperature, and solid fraction are affected by changes in the geometry of the boundary. We also predict how the induced stresses vary with the geometry of the boundary and the average solid fraction within the flow.

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Zusammenfassung Wir erhalten die Randbedingungen für die zweidimensionale Strömung identischer, beinahe elastischer, runder Scheiben, die sich in Wechselwirkung mit einer geraden Wand befinden, an der in gleichmäßigen Abständen Halbscheiben angebracht sind. Es werden Ausdrücke für die Übertragung von Impuls und Energie vom Rand auf den Strom aufgestellt, die durch den statisch errechneten Durchschnitt aller möglichen Scheibenkollisionen Wand-Strom erhalten werden. Wir verbessern die von Jenkins und Richman (1986) entwickelten Ausdrücke dadurch, daß bei der Berechnung der Mittelwerte eine erweiterte Geschwindigkeitsverteilung, die auf der Momentmethode beruht, einbezogen wurde. Außerdem entwickeln wir die Verteilungsfunktion an einem Punkt so nahe an der Wand, daß positive Gleitgeschwindigkeiten garantiert sind. Wir untersuchen eine zweidimensionale Scherströmung mit diesen Randbedingungen, die durch die parallelen unebenen Ränder getrieben wird. Die konstitutive Theorie, die wir anwenden, beinhaltet sowohl den Einfluß der Teilchenkollisionen als auch den des Teilchentransports auf die Übertragung von Impuls und Energie innerhalb der Strömung. Wir zeigen, wie die Profile der Geschwindigkeit, der Granu-lartemperatur und des Festkörperanteils, die sich ergeben, durch Veränderungen der Randgeometrie beeinflußt werden. Weiterhin können wir voraussagen, wie die erzeugten Spannungen sich mit der Randgeometrie und dem im Strom enthaltenen Festkörperanteil verändern.

     

A theory for grain-size reduction in granular flows of spheres

Summary We derive a kinetic theory for homogeneous granular shear flows of identical spheres in which collisions between particles result in small fractures on their peripheries and, over time, effectively reduce their average diameter. In obtaining statistically averaged constitutive relations for the rates of energy dissipation and mass loss, we employ the integral expression derived by Jenkins and Savage [1983] for the collisional source of a particle property. However, in calculating the stress, we modify their expression for the collisional flux in order to ensure that the stress is symmetric when the particles interact through central forces. The constitutive relations are employed in the balance equations for mass, momentum, and energy in order to predict, for a fixed shear rate and particle number density, the manner in which the solid fraction, granular temperature, and induced stresses vary with time.

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Zusammenfassung Wir entwickeln eine kinetische Theorie für die homogene Scherströmung von identischen Kugeln, in welcher die Zusammenstösse der Teilchen kleine Risse in ihrer Oberfläche verursachen und sich dadurch ihr mittlerer Durchmesser mit der Zeit verringert. Um die statistisch gemittelten konstitutiven Beziehungen für die Energiedissipations- und Massenverlustraten zu erhalten, verwenden wir den von Jenkins und Savage [1983] hergeleiteten Integralausdruck für die von den Kollisionen verursachte Quellenstärke einer Teilchenzustandsgrösse. Bei der Berechnung der Spannung verwenden wir jedoch einen abgeänderten Ausdruck für den Fluss durch Kollision; dadurch wird sichergestellt, dass der Spannungstensor symmetrisch ist, wenn die Kontaktkraft zwischen den Teilchen normal zur Kontaktebene wirkt. Die konstitutiven Beziehungen werden in die Gleichungen für die Erhaltung von Masse, Impuls und Energie eingesetzt, um zu berechnen, wie sich der Festkörperanteil, die Granulartemperatur und die induzierten Spannungen als Funktion der Zeit verändern; der Geschwindigkeitsgradient und die Anzahl Teilchen pro Volumen sind dabei konstant.