Wet oxidation of thin AlAs in cylindrical composite of GaAs/AlAs/GaAs

Lateral wet oxidation in a cylindrical composite, GaAs/AlAs/GaAs, with varying thickness of the AlAs layer has been investigated. The oxidation depth in AlAs was measured in the temperature range of 400–480 °C. At given temperature and time, the depth increases with the increase in thickness. The thickness effect was successfully interpreted based on the kinetic model of boundary layer diffusion. The results are consistent with the findings from early studies on samples of square and rectangular cross-sections with the same activation energy of the thermal process.     

Effects of partial oxidation of crumb rubber on properties of rubberized mortar

It is a generally accepted result that the inclusion of rubber particles causes the concrete to degrade physical properties of the concrete. In this study the crumb rubber was partially oxidized and used as additives of mortars. Dramatically, the compressive strength of the rubberized mortars (with 6 wt.%) was greater than that of mortars without the crumb rubber. To understand these phenomena, Fourier Transform Infrared Spectroscopy (FTIR) was used to explore the functional groups on surfaces of the crumb rubber, and Scanning Electron Microscopy (SEM) was used to observe microstructures of mortars. With the partial oxidation treatment, rubber surfaces produced hydrophilic functional groups as indicated by IR spectra and the hydration of the cement near the crumb rubber was enhanced as shown by SEM, leading to stronger mortars.     

Visually Dynamic Presentation of Proofs in Plane Geometry

We present the method for automated generation of visually dynamic presentations of plane geometry proofs based on the full-angle method. The proof generated by the full-angle method is organized hierarchically, thus it is particularly suitable for visual presentations. We also present the method for automated generation of visually dynamic presentation of proofs for the deductive database method with an additional new visual feature: given a geometrical configuration or a diagram, the final database (the fixpoint) in the deductive database method has numerous geometric properties organized into a few categories. By clicking each category, all properties of the configuration in this category are listed. And by clicking each of these properties, the corresponding geometry elements in the diagram blink or animate and, if needed, the proof of this property is generated.     

HMM-based ball hitting event exploration system for broadcast baseball video

With the dramatic growth of fandom population, a considerable amount of research efforts have been devoted to baseball video processing. However, little work focuses on the detailed follow-ups of ball hitting events. This paper proposes a HMM-based ball hitting event exploration system for broadcast baseball video. Utilizing the strictly-defined layout of the baseball field, the proposed system first detects the game-specific spatial patterns in the field, such as the field lines, the bases, the pitch mound, etc. Then, the play region—the currently camera-focused region of the baseball field is identified for frame type classification. Since the temporal patterns of presenting the game progress follow a prototypical order, we consider the classified frame types as observation symbols and recognize ball hitting events using HMM. Experiments conducted on broadcast baseball video show encouraging results in frame type classification and ball hitting event recognition. Three practical applications, including highlight clip extraction by user-designated query, storyboard construction, and similar event retrieval, are introduced to address the applicability of our system.     

Epoxidation of Butadiene Over Nickel Modified TS-1 Catalyst

Abstract  

Nickel modified Titanium silicalite 1 (TS-1) catalysts provided an environmentally benign and effective method for butadiene epoxidation. Certain loading of modified Ni in our system significantly promoted TS-1 catalytic activity. The product vinyloxirane (VO) was obtained with high yield of 0.49 mol/L (theoretic equilibrium value 0.52 mol/L). The turnover number (TON, determined as the molar VO obtained per molar Ti atom) reached 1,140. Besides, the catalyst kept high activity during five runs of reusability test. XRD, N₂ adsorption and desorption, TPR, XPS, FT-IR and DR UV–Vis were employed to characterize the specific Ni role to Ti-site in Ni/TS-1 catalysts.     

A Bipolar Host Material Containing Triphenylamine and Diphenylphosphoryl‐Substituted Fluorene Units for Highly Efficient Blue Electrophosphorescence

Highly efficient blue electrophosphorescent organic light‐emitting diodes incorporating a bipolar host, 2,7‐bis(diphenylphosphoryl)‐9‐[4‐(N,N‐diphenylamino)phenyl]‐9‐phenylfluorene (POAPF), doped with a conventional blue triplet emitter, iridium(III) bis[(4,6‐difluoro‐phenyl)pyridinato‐N,C^2´]picolinate (FIrpic) are fabricated. The molecular architecture of POAPF features an electron‐donating (p‐type) triphenylamine group and an electron‐accepting (n‐type) 2,7‐bis(diphenyl‐phosphoryl)fluorene segment linked through the sp³‐hybridized C9 position of the fluorene unit. The lack of conjugation between these p‐ and n‐type groups endows POAPF with a triplet energy gap (E_T) of 2.75 eV, which is sufficiently high to confine the triplet excitons on the blue‐emitting guest. In addition, the built‐in bipolar functionality facilitates both electron and hole injection. As a result, a POAPF‐based device doped with 7 wt% FIrpic exhibits a very low turn‐on voltage (2.5 V) and high electroluminescence efficiencies (20.6% and 36.7 lm W^?1). Even at the practical brightnesses of 100 and 1000 cd m^?2, the efficiencies remain high (20.2%/33.8 lm W^?1 and 18.8%/24.3 lm W^?1, respectively), making POAPF a promising material for use in low‐power‐consumption devices for next‐generation flat‐panel displays and light sources.     

ZnO nano-ridge structure and its application in inverted polymer solar cell

We report a unique nano-ridge structure of zinc oxide (ZnO) and its application in high performance inverted polymer solar cells. The ZnO nano-ridge structure was formed by a sol–gel process using a ramp annealing method. As the solvent slowly evaporated due to the low heating rate, there was sufficient time for the gel particles to structurally relax and pile up, resulting in a dense and undulated film. Nano-ridges with peak as high as 120 nm and valley to valley distance of about 500 nm were formed. This film provided an effective hole blocking layer and also an increased interfacial area for electron collection. An inverted bulk heterojunction polymer solar cell was fabricated using the ZnO nano-ridge film as the electron collecting layer. The device showed a high power conversion efficiency of 4.00%, an improvement of about 25% over similar solar cells made with a planar film of ZnO nanoparticles.     

Preparation of PZN-Based Ceramics Using a Sequential Mixing Columbite Method

In this experiment Pb(Zn_1/3Nb_2/3)O₃(PZN)-BaTiO₃ (BT)-Pb(Zr_0.52Ti_0.48)O₃ (PZT) ceramics were prepared using solid state reactions via columbite method by mixing the relevant oxides and were processed employing conventional sintering techniques. Dielectric, ferroelectric and piezoelectric properties were evaluated and the corresponding microstructures were examined using transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). The experimental results imply that it is difficult to prepare PZN-PZT-BT ceramics with a full perovskite structure using a conventional columbite method, i.e., PZN was prepared using the columbite method and then mixed, calcined and sintered with PT, PZ and BT. A modified approach (MC) of mixing and calcining all B-site elements first, then mixing and sintering with all A site elements was adopted. Electrical properties were enhanced but a small amount of pyrochlore phase still exists. Finally, a mixing and calcining sequence (sequential mixing columbite, SMC) of well calcined B-site elements, firstly with BaO then with PbO was utilized. A full perovskite structure of the specimen with excellent electrical properties can be obtained. Microstructural investigations showed Ba segregation at triple junctions for IC and MC processes, implying that stabilization of the perovskite structure of the specimens was not completely achieved due to element segregation.     

Economic Design of Averages Control Charts for Monitoring a Process with Correlated Samples

When an x control chart is used to monitor a manufacturing process, three parameters should be determined: the sample size, the sampling interval between successive samples, and the control limits for the chart. In 1956, Duncan presented the first cost model to determine the three parameters for the x charts, which is called the economic design of x charts. Traditionally, when designing a x chart, it is assumed that the measurements within a sample are independently distributed; however, this assumption may not be tenable. In this paper, we develop the economic design of x charts for correlated measurements within a sample. An example is presented to illustrate the solution procedure. From the results of the sensitivity analyses of this example, we find that if the measurements in the sample are positively correlated, highly correlated data result in a smaller sample size, a frequent sampling interval and narrower control limits; however, if the measurements in the sample are negatively correlated, highly correlated data yield a smaller sample size and narrower control limits.