Lehigh University

About: Lehigh University is a education organization based out in Bethlehem, Pennsylvania, United States. It is known for research contribution in the topics: Catalysis & Fracture mechanics. The organization has 12684 authors who have published 26550 publications receiving 770061 citations.

Subcolloidal Fe/Ag particles for reductive dehalogenation of chlorinated benzenes

Abstract: Subcolloidal (<0.1 μm) iron−silver (1% Ag) particles were synthesized for the transformation of chlorinated benzenes in aqueous solution. Hexachlorobenzene (HCB) (4 mg/L) was dechlorinated to tetra...

A Model of Academic Enablers and Elementary Reading/Language Arts Achievement

Abstract: This article includes a review of theoretical and empirical models of educational outcomes to identify student attitudes and behaviors that researchers have hypothesized to influence academic achie...

Relabeling Internal and External Validity for Applied Social Scientists.

Abstract: Confusion about the meaning of validity in quasi-experimental research can be addressed by carefully relabeling types of validity. Internal validity can more aptly be termed “local molar causal validity.” More tentatively, the “principle of proximal similarity” can be substituted for the concept of external validity.

Behavior and Design of Posttensioned Steel Frame Systems

Abstract: A posttensioned (PT) steel moment resisting frame is a self-centering earthquake resistant steel frame that uses posttensioning steel to compress the beam flanges against the column flanges at the connections. The posttensioning contributes to the moment capacity of the connections and provides an elastic restoring force that returns the frame to its pre-earthquake position. This paper describes the behavior and design of PT frames and PT frame systems, where a PT frame system is a PT frame with the collector elements that connect it to the floor system. The interaction of the floor system with the PT frame produces axial forces in the beams that add to those from the posttensioning. This paper outlines a performance-based seismic design approach for PT steel frame systems. Seismic performance levels, seismic input levels, structural limit states and capacities, and structural demands for PT frame systems are defined. The design objectives are outlined, design criteria are given, and a step-by-step design procedure is given. The design approach is evaluated via comparisons with time-history analysis results.

Interface states in MOS structures with 20–40 Å thick SiO2 films on nondegenerate Si

Abstract: MOS structures having different metal contacts on 20–40 A thick SiO2 films and non-degenerate Si have been investigated. These structures show large frequency dispersion of the measured admittance curves caused by carrier recombination in interface states. However, build-up of a Si inversion layer is not observed because the minority carriers are drained away by tunneling through the oxide into the metal. Interface state density distributions across the whole Si band gap are obtained by evaluating measured capacitance and conductance curves. Characteristic peaks of 0.12–0.30 eV half width are found for the metal contacts, Mg at 0.54 eV, Cu at 0.23 eV, Cr at 0.18 eV and 0.52 eV, and Au at 0.15 eV and 0.97 eV above the valence band edge. The position of a peak seems to be related to the valence of the metal. Interface states caused by Cr, Cu and Mg contacts are of acceptor type. Their capture cross-section obtained from conductance measurements varies between 10−7 and 10−18 cm−2. A rapid increase of the state density with decreasing oxide thickness or sample annealing indicates that the states are caused by metal diffusion through the oxide into the interface. An observed saturation of the state density at about 2 × 1013 cm−2 V−1 is possibly due to a limited solubility of metal impurities in the oxide.