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Among the metal hydrides, Th4H15 is the first reported superconductor with a relatively high Tc ≈ 8 K at ambient pressure. Here we report on the synthesis and characterization of a low-Tc superconducting modification of Th4H15, which is obtained via hydrogenating Th metal at 5 GPa and 800 °C by using the ammonia borane as the hydrogen source. Measurements of resistivity, magnetic susceptibility, and specific heat confirm that the obtained Th4H15 sample shows a bulk superconducting transition at Tc ≈ 6 K, which is about 2 K lower than that reported previously. Various characteristic superconducting parameters have been extracted for this compound and unusual lattice dynamics were evidenced from the specific-heat analysis. [ABSTRACT FROM AUTHOR]

Te-doped and ZnTe-doped diluted ZnSeTe samples were grown by using metal-organic chemical vapor deposition. The green lights emitted from these two samples in the photoluminescence (PL) measurement have different peak emission energies and can be attributed to different emission mechanisms. For the Te-doped sample, the PL emission band is excitation laser power independent, the lifetime of the PL emission is short, and the PL emission could be attributed to the emission originated from Te isoelectronic centers. For the ZnTe-doped sample, the energy of the green emission band is laser power dependent, the PL lifetime is much longer than the Te-doped sample, and the PL emission could be attributed to the emission from type-II ZnTe/ZnSe quantum dots. The results demonstrate that there are two different mechanisms responsible for the green PL emission in ZnSeTe system and our growth methods provide a way of selecting one of the two mechanisms for the green light emission in this system. [ABSTRACT FROM AUTHOR]

Effective equipment management is becoming one of the key factors in keeping a competitive advantage in the dynamic business environment since equipment is an important asset for manufacturing companies. Nowadays, maintenance administration has become one of the most important tasks in equipment management, particularly in manufacturing industries. Equipment management system (EMS) aims at reducing maintenance cost and production loss caused by machine breakdown. In addition, EMS can assist equipment engineers to make the right maintenance decisions at the right time, and at the right shop floor. Traditional computerized maintenance management systems (CMMS) have helped equipment engineers to deal with maintenance operations, but they lack decision support capability. In this paper, we design a data warehouse (DW) for EMS to help equipment engineers make maintenance decisions with various equipment related dimensions to improve effectiveness. A set of cubes can be built from EMS DW for the purpose of decision-making. In order to achieve a reasonable query response time under the memory space limit, a mechanism of partial materialization based on genetic algorithms (GAs) is adopted to design data cubes in the EMS DW. From the computational results the proposed GA-based approach for cube design can be applied to effectively select the appropriate multi-dimensional views for equipment management. [ABSTRACT FROM AUTHOR]

Dimensionless three-dimensional universal phase and lift force diagrams of a microbubble (or pendant drop) in static liquid on a solid surface (or orifice) are presented in this work. Microbubble dynamics has been found to play a vital role in mass, momentum, energy, and concentration transfer rates in contemporary micro- and nanosciences and technologies. In this study, dimensionless phase and force diagrams are introduced by utilizing the analytical solutions of the microbubble shape reported in the literature. It shows that phase and force diagrams can be universally specified by two dimensionless independent parameters, Bond number, and contact angle (or base radius). Based on the presence of an inflection point or neck on the microbubble surface, each diagram exhibits three regions. Growth, detachment, and entrapment of a microbubble can be described by path lines in three regions. The corresponding universal total lift forces include hydrostatic buoyancy, difference in gas, and hydrostatic pressures at the base, capillary pressure, as well as surface tension induced by the variation of circumference, which has not been treated in the literature so far. In the absence of viscous stress and Marangoni force, the total lift force equals surface tension induced by the variation of circumference. The latter can be an attaching or lifting force, depending on whether the state in the distinct regions and contact angle is less than or greater than a critical angle. The critical angle, which is slightly less than the inclination angle at the inflection point, is decreased with increasing Bond number. [ABSTRACT FROM AUTHOR]

This study evaluates the accuracy of two alternative models for the kill rate of different visual defects and the yield estimation by using large amount of practical inspection data (140 6-inch wafers containing 70 560 dies) in semiconductor manufacturing. One model assumed that the visual defects are randomly distributed on a wafer die; another model considered that clustering visual defects may occur on a wafer die. The results show that two models are both capable of predicting the yield precisely. The results also suggest that the model assuming clustering visual defects on a die is more accurate based on the analysis of Taguchi's signal-to-noise (SN) ratio. The same practices can be implemented with other types of wafer such as 8 inch and 12 inch. Precise prediction for the kill rate of different types of visual defects and the yield in the long supply of semiconductor industry is critical since the requirement of material and the reserved capacity can be largely reduced. [ABSTRACT FROM AUTHOR]