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101.
Cheng‐Yao Lin Jerry Becker Mi‐Ran Byun Der‐Ching Yang Tsai‐Wei Huang 《School science and mathematics》2013,113(1):41-51
This study examined (a) the differences in preservice teachers’ procedural knowledge in four areas of fraction operations in Taiwan and the United States, (b) the differences in preservice teachers’ conceptual knowledge in four areas of fraction operations in Taiwan and the United States, and (c) correlation in preservice teachers’ conceptual knowledge and procedural knowledge of fractions in Taiwan and the United States. Participants were preservice teachers (N = 49) in a teacher education program in the United States and comparable Chinese preservice teachers (N = 47). Results indicated that Chinese preservice teachers performed better in procedural knowledge on fraction operations than American preservice teachers. No significant differences were found for conceptual knowledge on fraction division. Further, the correlation in this study showed that for Chinese and American preservice teachers, the relationship between conceptual and procedural knowledge of fraction operations was weak. 相似文献
102.
Quasiparticle self-consistent many-body perturbation theory (MBPT) methods that update both eigenvalues and eigenvectors can calculate the excited-state properties of molecular systems without depending on the choice of starting points. However, those methods are computationally intensive even on modern multi-core central processing units (CPUs) and thus typically limited to small systems. Many-core accelerators such as graphics processing units (GPUs) may be able to boost the performance of those methods without losing accuracy, making starting-point-independent MBPT methods applicable to large systems. Here, we GPU accelerate MOLGW, a Gaussian-based MBPT code for molecules, with open accelerators (OpenACC) and achieve speedups of up to over 32 open multi-processing (OpenMP) CPU threads. 相似文献
103.
We studied the thermal stability of HfO2 on an InP structure when an Al2O3 interface passivation layer (PL) was introduced. In contrast to the thick (~4 nm) Al2O3‐PL, an almost complete disappearance of the thin (~1 nm) Al2O3‐PL was observed after a post‐deposition anneal at 600 °C. Based on various chemical and electrical analyses, this was attributed to the intermixing of the thin Al2O3‐PL with HfO2, which might have been accompanied by the out‐diffusion of a substantial amount of substrate elements. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
104.
105.
Consider the Lie group SO0(n, 1) with the left-invariant metric coming from the Killing-Cartan form. The maximal compact subgroup SO(n) of the isometry group acts from the left and right. This paper studies the geometry of the quotient space of the homogeneous submersion SO0(n, 1) → SO(n)\SO0(n, 1). It is a cohomogeneity one manifold, which can be expressed as a warped product. Its group of isometries, geodesics, and sectional curvatures are calculated. 相似文献
106.
MBHA (4-methylbenzhydrylamine) resin has been extensively used as a solid support for the synthesis of peptide amides. Herein, we prepared the core-shell-type MBHA resin by benzotriazole-catalyzed amidoalkylation and partial hydrolysis. The core-shell structure of the MBHA resin was confirmed by two-photon microscopy and its synthetic performance in solid-phase peptide synthesis (SPPS) was evaluated. 相似文献
107.
Wongi Jang Richard Taylor IV Pascal N. Eyimegwu Prof. Hongsik Byun Prof. Jun-Hyun Kim 《Chemphyschem》2019,20(1):70-77
Composite materials consisting of nanoscale gold particles and protective polymer shells were designed and tested as catalysts in various chemical reactions. Initially, the systematic incorporation of multiple gold nanoparticles into a poly(N-isopropylacrylamide) particle was achieved by an in situ method under light irradiation. The degree of gold nanoparticle loading, along with the structural and morphological properties, was examined as a function of the amount of initial gold ions and reducing agent. As these gold nanoparticles were physically-embedded within the polymer particle in the absence of strong interfacial interactions between the gold nanoparticles and polymer matrix, the readily-accessible surface of the gold nanoparticles with a highly increased stability allowed for their use as recyclable catalysts in oxidation, reduction, and coupling reactions. Overall, the ability to integrate catalytically-active metal nanoparticles within polymer particles in situ allows for designing novel composite materials for multi-purpose catalytic systems. 相似文献
108.
Jeong Moon Jihyun Byun Hongki Kim Jinyoung Jeong Eun‐Kyung Lim Juyeon Jung Soojeong Cho Woo Kyung Cho Taejoon Kang 《Macromolecular bioscience》2019,19(6)
For the construction of high‐performance biosensor, it is important to interface bioreceptors with the sensor surface densely and in the optimal orientation. Herein, a simple surface modification method that can optimally immobilize antibodies onto various kinds of surfaces is reported. For the surface modification, a mixture of polydopamine (PDA) and protein G was employed. PDA is a representative mussel‐inspired polymer, and protein G is an immunoglobulin‐binding protein that enables an antibody to have an optimal orientation. The surface characteristics of PDA/Protein G mixture‐coated substrates are analyzed and the PDA/protein G ratio is optimized to maximize the antibody binding efficiency. Moreover, the antibody‐immobilized substrates are applied to the detection of influenza viruses with the naked eye, providing a detection limit of 2.9 × 103 pfu mL‐1. Importantly, the several substrates (glass, SiO2, Si, Al2O3, polyethylene terephthalate, polyethylene, polypropylene, and paper) can be modified by simple incubation with the mixture of PDA/protein G, and then the anti‐influenza A H1N1 antibodies can be immobilized on the substrates successfully. Regardless of the substrate, the influenza viruses are detectable after the sandwich immunoreaction and silver enhancement procedure. It is anticipated that the developed PDA/protein G coating method will extend the range of applicable materials for biosensing. 相似文献
109.
Jung Ah Byun Bryan VanSchouwen Nishi Parikh Madoka Akimoto Eric Tyler McNicholl Giuseppe Melacini 《Chemical science》2021,12(34):11565
Allosteric pluripotency arises when an allosteric effector switches from agonist to antagonist depending on the experimental conditions. For example, the Rp-cAMPS ligand of Protein Kinase A (PKA) switches from agonist to antagonist as the MgATP concentration increases and/or the kinase substrate affinity or concentration decreases. Understanding allosteric pluripotency is essential to design effective allosteric therapeutics with minimal side effects. Allosteric pluripotency of PKA arises from divergent allosteric responses of two homologous tandem cAMP-binding domains, resulting in a free energy landscape for the Rp-cAMPS-bound PKA regulatory subunit R1a in which the ground state is kinase inhibition-incompetent and the kinase inhibition-competent state is excited. The magnitude of the free energy difference between the ground non-inhibitory and excited inhibitory states (ΔGR,Gap) relative to the effective free energy of R1a binding to the catalytic subunit of PKA (ΔGR:C) dictates whether the antagonism-to-agonism switch occurs. However, the key drivers of ΔGR,Gap are not fully understood. Here, by analyzing an R1a mutant that selectively silences allosteric pluripotency, we show that a major determinant of ΔGR,Gap unexpectedly arises from state-selective frustration in the ground inhibition-incompetent state of Rp-cAMPS-bound R1a. Such frustration is caused by steric clashes between the phosphate-binding cassette and the helices preceding the lid, which interact with the phosphate and base of Rp-cAMPS, respectively. These clashes are absent in the excited inhibitory state, thus reducing the ΔGR,Gap to values comparable to ΔGR:C, as needed for allosteric pluripotency to occur. The resulting model of allosteric pluripotency is anticipated to assist the design of effective allosteric modulators.The Rp-cAMPS ligand of protein kinase A switches from agonist to antagonist depending on metabolite and proteomic contexts. We show that the state-selective frustration is a key driver of this allosteric pluripotency phenomenon. 相似文献
110.