Ink‐jet‐printable phosphorescent organic light‐emitting‐diode devices

Abstract— A novel method for the fabrication of ink‐jet‐printed organic light‐emitting‐diode devices is discussed. Unlike previously reported solution‐processed OLED devices, the emissive layer of OLED devices reported here does not contain polymeric materials. The emission of the ink‐jet‐printed P²OLED (IJ‐P²OLED) device is demonstrated for the first time. It shows good color and uniform emission although it uses small‐molecule solution. Ink‐jet‐printed green P²OLED devices possess a high luminous efficiency of 22 cd/A at 2000 cd/m² and is based on phosphorescent emission. The latest solution‐processed phosphorescent OLED performance by spin‐coating is disclosed. The red P²OLED exhibits a projected LT50 of >53,000 hours with a luminous efficiency of 9 cd/A at 500 cd/m². The green P²OLED shows a projected LT50 of >52,000 hours with a luminous efficiency of 35 cd/A at 1000 cd/m². Also discussed is a newly developed sky‐blue P²OLED with a projected LT50 of >3000 hour and a luminous efficiency of 18 cd/A at 500 cd/m².     

Printable phosphorescent organic light‐emitting devices

Abstract— A new approach to full‐color printable phosphorescent organic light‐emitting devices (P²OLEDs) is reported. Unlike conventional solution‐processed OLEDs that contain conjugated polymers in the emissive layer, the P²OLED's emissive layer consists of small‐molecule materials. A red P²OLED that exhibits a luminous efficiency of 11.6 cd/A and a projected lifetime of 100,000 hours from an initial luminance of 500 cd/m², a green P²OLED with a luminous efficiency of 34 cd/A and a projected lifetime of 63,000 hours from an initial luminance of 1000 cd/m², a light‐blue P²OLED with a luminous efficiency of 19 cd/A and a projected lifetime 6000 hours from an initial luminance of 500 cd/m², and a blue P²OLED with a luminous efficiency of 6.2 cd/A and a projected lifetime of 1000 hours from an initial luminance of 500 cd/m² is presented.     

Space and time efficiency of the forest-of-quadtrees representation

A forest of quadtrees is a refinement of a quadtree data structure that is used to represent planar regions. A forest of quadtrees provides space savings over regular quadtrees by concentrating vital information. The paper presents some of the properties of a forest of quadtrees and studies the storage requirements for the case in which a single 2^m × 2^m region is equally likely to occur in any position within a 2ⁿ × 2ⁿ image. Space and time efficiency are investigated for the forest-of-quadtrees representation as compared with the quadtree representation for various cases.     

Controllability of a Fokker-Planck equation,the Schrödinger system,and a related stochastic optimal control (revised version)

A controllability problem for a Fokker-Planck equation is termedProblem A. Under proper assumptions, a solution (v^*, Ф^*) to that problem is constructed by a Theorem of Jamison. Theorem 2 gives a sufficiency condition concerning the given initial and terminal data for that solution to exist. Theorem 3 states that v^* is an optimal feedback control for a stochastic optimal control problem with constraint on the end-state, termedProblem B. Further, v^* corresponds to the minimum of an entropy distance. Finally, Problem A is transformed into a controllability problem for a stochastic differential equation, termedProblem C: the solution to Problem C corresponding to the one constructed in Problem A is the Markovian process satisfying the given end conditions in a set of reciprocal processes of Jamison.     

Red phosphor Li2Mg2(WO4)3: Eu3+ with lyonsite structure for near ultraviolet light-emitting diodes

A series of Eu³⁺-activated Li₂Mg₂(WO₄)₃ (LMW) materials were synthesized by high temperature solid state reactions. The phosphor can be effectively excited by 394 nm near ultraviolet light and emit intense red light with high color purity. Prepared phosphors can be indexed to LMW with particular lyonsite structure. The occupation of Eu³⁺ in LMW is selective. Most of Eu³⁺ comes into ¹A sites without inversion symmetry. The present research suggests that LMW is a suitable host for luminescence applications and Eu³⁺-activated LMW is a promising phosphor for phosphor-converted white light-emitting diodes.     

Mathematical Model of Interaction of a Symmetric Top with an Axially Symmetric External Field

A symmetric top is considered, which is a particular case of a mechanical top that is usually described by the canonical Poisson structure on T^*SE (3). This structure is invariant under the right action of the rotation group SO(3), but the Hamiltonian of the symmetric top is invariant only under the right action of the subgroup S ¹, which corresponds to the rotation of the symmetric top around its axis of symmetry. This Poisson structure is obtained as the reduction T^* SE (3) / S ¹. A Hamiltonian and motion equations are proposed that describe a wide class of interaction models of the symmetric top with an axially symmetric external field.     

On problem transformability in VLSI

The two basic performance parameters that capture the complexity of any VLSI chip are the area of the chip,A, and the computation time,T. A systematic approach for establishing lower bounds onA is presented. This approach relatesA to the bisection flow, ?. A theory of problem transformation based on ?, which captures bothAT ² andA complexity, is developed. A fundamental problem, namely, element uniqueness, is chosen as a computational prototype. It is shown under general input/output protocol assumptions that any chip that decides ifn elements (each with (1+?)lognbits) are unique must have ?=ω(nlogn), and thus, AT²=ω(n ²log² n), andA= ω(nlogn). A theory of VLSI transformability reveals the inherentAT ² andA complexity of a large class of related problems.     

Robustness of a discrete dynamical process with a given set of attainability

A linear discrete system x ^{(k +1)} = A x ^(k) with a given set of attainability (c, x( ^N)) ≥ c ₀ is considered. The influence of small variations of problem parameters on the attainability of a required set is investigated. For the control system x ^(k+1) = Ax ^(k) + Bu ^(k), the choice of a controller as a feedback in state u(k) = Kx ^(k) is studied.     

The super spanning connectivity and super spanning laceability of the enhanced hypercubes

A k -container C(u,v) of a graph G is a set of k disjoint paths between u and v. A k-container C(u,v) of G is a k ^* -container if it contains all vertices of G. A graph G is k ^* -connected if there exists a k ^*-container between any two distinct vertices of G. Therefore, a graph is 1^*-connected (respectively, 2^*-connected) if and only if it is Hamiltonian connected (respectively, Hamiltonian). A graph G is super spanning connected if there exists a k ^*-container between any two distinct vertices of G for every k with 1≤k≤κ(G) where κ(G) is the connectivity of G. A bipartite graph G is k ^* -laceable if there exists a k ^*-container between any two vertices from different partite set of G. A bipartite graph G is super spanning laceable if there exists a k ^*-container between any two vertices from different partite set of G for every k with 1≤k≤κ(G). In this paper, we prove that the enhanced hypercube Q _n,m is super spanning laceable if m is an odd integer and super spanning connected if otherwise.

A new composite body method for manipulator dynamics

This article presents a new composite body method for numerically forming the inertia matrix and the bias vector of manipulators, which is more efficient than the other two existing types of composite body methods. The main discrepancy of this one from the existing ones is that all points in a manipulator are observed from the origin of the base frame and the distances are all measured from this origin. The required computations of the present method for the inertia matrix and the bias vector of a manipulator with n rotational joints are (10.5n² + 38.5n - 85)M + (6n² + 39n - 70)A and (12.5n² + 5.5n + 3)M + (9n² + n)A, respectively, where “M” denotes multiplications, “A” does additions. In numerically forming the inertia matrix, the present method is more efficient than other methods in the literature for a manipulator with five or more joints; whereas this method is also superior to the recursive Newton-Euler formulation in computing the bias vector for a manipulator with six or less joints.     

Optimal Finite Characterization of Linear Problems with Inexact Data

Abstract. For many linear problems, in order to check whether a certain property is true for all matrices A from an interval matrix A, it is sufficient to check this property for finitely many “vertex” matrices A ∈ A. J. Rohn has discovered that we do not need to use all 2ⁿ² vertex matrices, it is sufficient to only check these properties for 2²ⁿ⁻¹ ≪ 2ⁿ² vertex matrices of a special type A_yz. In this paper, we show that a further reduction is impossible: without checking all 2²ⁿ⁻¹ matrices A_yz, we cannot guarantee that the desired property holds for all A ϵ A. Thus, these special vertex matrices provide an optimal finite characterization of linear problems with inexact data.     

A run sum Hotelling’s χ2 control chart

A run sum Hotelling’s χ² control chart is proposed and its average run length (ARL) performance is evaluated using the Markov chain approach. A fast initial response (FIR) feature of this chart is also considered. In the optimization of the run sum χ² chart, computer programs are used to compute the chart’s optimal parameters. It is shown that the run sum χ² chart is superior to the various χ² charts with runs rules and the synthetic χ² chart, for all sizes of shifts in the mean vector, but less sensitive than the multivariate EWMA (MEWMA) chart toward small shifts. The sensitivity of the run sum χ² chart in detecting small shifts can be further enhanced by adding more regions and scores, so that this chart is as competitive as the MEWMA chart. We reckon that the run sum χ² chart is a relatively easy and effective tool for practitioners, as the χ² chart’s statistics can be plotted in its original scale of measurement, in contrast to the MEWMA chart which plots the transformed measurements.     

Optoelectronic properties of poly(fluorene) co‐polymer light‐emitting devices on a plastic substrate*

Abstract— The optoelectronic properties of red, green, and blue poly(fluorene) co‐polymer light‐emitting devices (PLEDs) on a plastic substrate having a multi‐layered structure with water vapor and oxygen transmission rates of less than 10^?5 g/cm²‐day‐atm and 10^?7 cc/cm²‐day‐atm, respectively, is reported. A semitransparent thin metal multi‐layer (i.e., Au/Ag/Au or Ag/Au/Ag) is placed between the plastic substrate and the ITO coating, achieving a low sheet resistance of 12–13 Ω/□ and an adequate optical transmission greater than 75%. A wider color gamut and a maximum emission efficiency of 0.7, 10, and 1.7 cd/A for red, green, and blue PLEDs, respectively, was obtained. Finally, a simple equivalent‐circuit model was used to simulate the current‐density—voltage characteristics of PLEDs.     

Inherent robustness of MRAC schemes

A standard model reference adaptive control (MRAC) scheme without modification of the adaptive law is inherently robust with respect to L^∞ ∩ L² disturbances in the sense that all closed-loop signals remain bounded and the tracking error belongs to L^∞ ∩ L². A MRAC scheme with a new adaptive law is inherently robust with respect to the disturbances in L^∞ ∩ L^1+α, 0 < α < ∞, with an L^1+β tracking error, for .     

A scattering model for perfectly conducting random surfaces II. Range of validity

Abstract

A recent st udy of the range of validity of the surface scattering model by Eftimiu using a two-dimensional surface is re-examined with a more realistic surface correlation function that is everywhere-differentiable and vanishes gradually at infinity. Ii is shown that a sufficient condition on the range of validity is that cos² θ [(kσ)²/(kc)^1/2]exp{?[2kc(1?sinθ)]^1/2} ? 1 where k is the electrical wave-number, 0 is the angle of incidence and a and c are the surface standard deviation and the surface correlation parameter respectively.     

Application of rhodamine B thiolactone to fluorescence imaging of Hg in Arabidopsis thaliana

Exposure to mercury causes severe damage to plants, animals and even humans. Concern over mercury toxicity has encouraged the development of efficient, sensitive, and selective methods for the in vivo detection of mercury. Although a variety of studies have been published describing fluorescence imaging of mercury in animal cells and tissues, no in vivo monitoring has been developed for plant systems until now. In this paper, we report the semi-quantitative fluorescence imaging of Hg²⁺ ions in a common model plant Arabidopsis thaliana (A. thaliana), with rhodamine B thiolactone (RBS) as a novel Hg²⁺ probe. The experimental results show that RBS is plant cell wall and cell membrane permeable, and the probe responds selectively to Hg²⁺ ions instead of the other species in plant systems. Real-time monitoring of Hg²⁺ absorption in roots of A. thaliana by RBS shows that saturation of Hg²⁺ uptake could occur in a short period of 3 days at most. The transportation and accumulation of Hg²⁺ ions in roots of A. thaliana have also been studied, revealing that most of Hg²⁺ ions reside in root cap and meristematic zone, and only a small amount of Hg²⁺ ions can reach the maturation zone. This indicates that the interaction of Hg²⁺ ions with any Hg²⁺-philic species including proteins in these regions may be responsible for plant poisoning and even death.     

Message Pattern Routing in Hypercubes: A Distribute-Concentrate Approach

A broad class of message patterns in multicomputers can be represented in the (^s_d)-mask formalism. In this paper, we propose a novel approach to routing (^s_d)-mask patterns in hypercubes. Transformations of (^s_d)-masks rather than physical data movements are considered for conceptual simplicity. A transformation from the source mask to the destination mask is composed of a sequence of basic relabeling operations on the masks, which constitute a set of basic routing steps in the hypercube. A distribute-concentrate routing scheme is introduced to dissipate channel conflicts. Based on the scheme, efficient algorithms for routing (^s_d)-mask patterns with varied message lengths in single-port and all-port hypercubes are derived. Our approach encompasses many previous optimal algorithms as special cases. Experiments of these algorithms on various message patterns characterized by the numbers of source processors are conducted. The results provide further insights into the effects of multipath routing on the communication performance.     

Mixed H2/H∞ problems: approximated solutions by Galerkin methods

This paper presents a Galerkin method to solve the mixed H²/H^∞ optimal control problem. In this method the generator set is built step-by-step by an optimization procedure. Algorithm convergence is proved in the setting of weighted Hardy spaces. Some examples are discussed, showing the accelerated convergence obtained by this new algorithm and its numerical features. A particular quadratic optimal control problem on finite-dimensional linear systems under robustness constraints is developed as a motivation for the mixed H²/H^∞ problem.     

An Improved Protocol for Deadlock and Livelock Avoidance Resource Co-allocation in Network Computing

A multitude of applications require simultaneous access to multiple kinds of resources scatted in distributed sites. This problem is known as resource co-allocation which has evolved as a hot topic in network computing. How to design a kind of high-performance protocol for deadlock and livelock avoidance resource co-allocation becomes a challenging problem. In this paper, we propose a new protocol OODP³ (Optimal ODP³) which is based on the currently popular protocol ODP³ (Order-based Deadlock Prevention Protocol with Parallel requests).OODP³ not only inherits the advantage of ODP³ but also guarantees the fulfillment of resource co-allocation within polynomial time. Theoretical proof is conducted to verify the correctness of OODP³. Experimental results also show that OODP³ achieves the better performance improvements than the existing deadlock and livelock avoidance protocol.