University of Houston

About: University of Houston is a education organization based out in Houston, Texas, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 23074 authors who have published 53903 publications receiving 1641968 citations.

Nanocomposites: Structure, Phase Behavior, and Properties

Abstract: It is well recognized that nanocomposites formed by adding nanoparticles to polymers can have significantly enhanced properties relative to the native polymer. This review focuses on three aspects that are central to the outstanding problem of realizing these promised property improvements. First, we ask if there exist general strategies to control nanoparticle spatial distribution. This is an important question because it is commonly accepted that the nanoparticle dispersion state crucially affects property improvements. Because ideas on macroscale composites suggest that optimizing different properties requires different dispersion states, we next ask if we can predict a priori the particle dispersion and organization state that can optimize one (or more) properties of the resulting nanocomposite. Finally, we examine the role that particle shape plays in affecting dispersion and hence property control. This review focuses on recent advances concerning these underpinning points and how they affect measur...

Energy Dependence of Moments of Net-Proton Multiplicity Distributions at RHIC

Abstract: We report the beam energy (root S-NN = 7.7-200 GeV) and collision centrality dependence of the mean (M), standard deviation (sigma), skewness (S), and kurtosis (kappa) of the net-proton multiplicity distributions in Au + Au collisions. The measurements are carried out by the STAR experiment at midrapidity (vertical bar y vertical bar < 0.5) and within the transverse momentum range 0.4 < p(T) < 0.8 GeV/c in the first phase of the Beam Energy Scan program at the Relativistic Heavy Ion Collider. These measurements are important for understanding the quantum chromodynamic phase diagram. The products of the moments, S sigma and K sigma(2), are sensitive to the correlation length of the hot and dense medium created in the collisions and are related to the ratios of baryon number susceptibilities of corresponding orders. The products of moments are found to have values significantly below the Skellam expectation and close to expectations based on independent proton and antiproton production. The measurements are compared to a transport model calculation to understand the effect of acceptance and baryon number conservation and also to a hadron resonance gas model.

Deep Ultraviolet Nonlinear Optical Materials

Abstract: Deep ultraviolet (absorption edge 6.2 eV) nonlinear optical (NLO) materials are of current interest owing to their technological applications and materials design challenges. Technologically, the materials are used in laser systems, atto-second pulse generation, semiconductor manufacturing, and photolithography. Designing and synthesizing a deep UV NLO material requires crystallographic non-centrosymmetry, a wide UV transparency range, a large second-harmonic generating coefficient (dij > 0.39 pm/V), moderate birefringence (Δn ∼ 0.07), chemical stability and resistance to laser damage, and ease in the growth of large high-quality single crystals. This review examines the known deep UV NLO materials with respect to their crystal structure, band gap, SHG efficiency, laser damage threshold, and birefringence. Finally, future directions with respect to new deep UV NLO materials are discussed.

Effects of Audit Quality on Earnings Management and Cost of Equity Capital: Evidence from China†

Abstract: We examine the effects of audit quality on earnings management and cost of equity capital for two groups of Chinese firms: state-owned enterprises (SOEs) and non-state-owned enterprises (NSOEs). The differences in the nature of the ownership, agency relations and bankruptcy risks lead SOEs to have weaker incentives than NSOEs to engage in earnings management. As a result, the effect of audit quality in reducing earnings management will be greater for NSOEs than for SOEs. In addition, investors’ pricing of information risk as reflected in the cost of equity capital will be more pronounced for NSOEs than for SOEs with high and low audit quality. We find empirical evidence consistent with these hypotheses. Our findings indicate that (1) while high-quality auditors play a governance role in China, that role is limited to a subset of firms, and (2) even under the same legal jurisdiction, the effects of audit quality (in the form of lower earnings management and cost of equity capital) vary across firms with different ownership structures. Our study extends prior research by focusing on the economic consequences of SOEs’ and NSOEs’ auditor choices and underscores the importance of controlling for ownership type when conducting audit research.