North Carolina State University

About: North Carolina State University is a education organization based out in Raleigh, North Carolina, United States. It is known for research contribution in the topics: Population & Thin film. The organization has 44161 authors who have published 101744 publications receiving 3456774 citations. The organization is also known as: NCSU & North Carolina State University at Raleigh.

Layer-Dependent Electrocatalysis of MoS2 for Hydrogen Evolution

Abstract: The quantitative correlation of the catalytic activity with the microscopic structure of heterogeneous catalysts is a major challenge for the field of catalysis science. It requests synergistic capabilities to tailor the structure with atomic scale precision and to control the catalytic reaction to proceed through well-defined pathways. Here we leverage on the controlled growth of MoS2 atomically thin films to demonstrate that the catalytic activity of MoS2 for the hydrogen evolution reaction decreases by a factor of ∼4.47 for the addition of every one more layer. Similar layer dependence is also found in edge-riched MoS2 pyramid platelets. This layer-dependent electrocatalysis can be correlated to the hopping of electrons in the vertical direction of MoS2 layers over an interlayer potential barrier. Our experimental results suggest the potential barrier to be 0.119 V, consistent with theoretical calculations. Different from the conventional wisdom, which states that the number of edge sites is important,...

Absolute Measurement of Domain Composition and Nanoscale Size Distribution Explains Performance in PTB7:PC71BM Solar Cells

Abstract: The importance of morphology to organic solar cell performance is well known, but to date, the lack of quantitative, nanoscale and statistical morphological information has hindered obtaining direct links to device function. Here resonant X-ray scattering and microscopy are combined to quantitatively measure the nanoscale domain size, distribution and composition in high efficiency solar cells based on PTB7 and PC71BM. The results show that the solvent additive diiodooctane dramatically shrinks the domain size of pure fullerene agglomerates that are embedded in a polymer-rich 70/30 wt.% molecularly mixed matrix, while preserving the domain composition relative to additive-free devices. The fundamental miscibility between the species – measured to be equal to the device's matrix composition – is likely the dominant factor behind the overall morphology with the additive affecting the dispersion of excess fullerene. As even the molecular ordering measured by X-ray diffraction is unchanged between the two processing routes the change in the distribution of domain size and therefore increased domain interface is primarily responsible for the dramatic increase in device performance. While fullerene exciton harvesting is clearly one significant cause of the increase owing to smaller domains, a measured increase in harvesting from the polymer species indicates that the molecular mixing is not the reason for the high efficiency in this system. Rather, excitations in the polymer likely require proximity to a pure fullerene phase for efficient charge separation and transport. Furthermore, in contrast to previous measurements on a PTB7-based system, a hierarchical morphology was not observed, indicating that it is not necessary for high performance.

Integrating Operations and Marketing Perspectives of Product Innovation: The Influence of Organizational Process Factors and Capabilities on Development Performance

Abstract: This paper adopts a multidisciplinary view of innovation by integrating operations and marketing perspectives of product development. The conceptual framework builds on the resource-based view of the firm and organizational information-processing theory to characterize relationships among organizational process factors, product development capabilities, critical uncertainties, and operational/market performance in product development projects. Data from a cross-sectional sample of 120 completed development projects for assembled goods is analyzed via a two-stage hierarchical moderated regression approach. The findings show that: 1 the organizational process factors studied are associated with achievement of operational outcome targets for product quality, unit cost, and time-to-market; 2 achievement of operational outcomes aids the achievement of market outcomes, in turn suggesting that development capabilities are indeed valuable firm resources; and 3 these relationships are robust under conditions of technological, market, and environmental uncertainty. This article provides practical insight into how product development projects can be better managed for operational and market success. Additionally, this article sets a theoretical and empirical basis for future research on the influence of organizational process factors and capabilities on diverse product-innovation outcomes.

Auxin response factors ARF6 and ARF8 promote jasmonic acid production and flower maturation

Abstract: Pollination in flowering plants requires that anthers release pollen when the gynoecium is competent to support fertilization. We show that in Arabidopsis thaliana, two paralogous auxin response transcription factors, ARF6 and ARF8, regulate both stamen and gynoecium maturation. arf6 arf8 double-null mutant flowers arrested as infertile closed buds with short petals, short stamen filaments, undehisced anthers that did not release pollen and immature gynoecia. Numerous developmentally regulated genes failed to be induced. ARF6 and ARF8 thus coordinate the transition from immature to mature fertile flowers. Jasmonic acid (JA) measurements and JA feeding experiments showed that decreased jasmonate production caused the block in pollen release, but not the gynoecium arrest. The double mutant had altered auxin responsive gene expression. However, whole flower auxin levels did not change during flower maturation, suggesting that auxin might regulate flower maturation only under specific environmental conditions, or in localized organs or tissues of flowers. arf6 and arf8 single mutants and sesquimutants (homozygous for one mutation and heterozygous for the other) had delayed stamen development and decreased fecundity, indicating that ARF6 and ARF8 gene dosage affects timing of flower maturation quantitatively.