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Adjacent strong edge colorings and total colorings of regular graphs

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Science China Mathematics 2009年第5期52卷 973-980页

作者： WOODALL douglas r School of Mathematical Sciences University of NottinghamNottinghamNG7 2RDUK

It is conjectured that X as ′ (G) = X t (G) for every k-regular graph G with no C 5 component (k ? 2). This conjecture is shown to be true for many classes of graphs, including: graphs of type 1; 2-regular, 3-regular and (|V(G)| - 2)-regular graphs; bipartite graphs; balanced complete multipartite graphs; k-cubes; and joins of two matchings or cycles.

关键词： graph total coloring adjacent strong edge coloring 05C15 68r10

HYErS-ULAM STABILITY OF SECOND-OrDEr LINEAr DYNAMIC EQUATIONS ON TIME SCALES

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Acta Mathematica Scientia 2021年第5期41卷 1809-1826页

作者： douglas r.ANDErSON Masakazu ONITSUKA Department of Mathematics Concordia CollegeMoorheadMN 56562 USA Department of Applied Mathematics kayama University of ScienceOkayama700-0005Japan

We investigate the Hyers-Ulam stability(HUS)of certain second-order linear constant coefficient dynamic equations on time scales,building on recent results for first-order constant coefficient time-scale *** particular,for the case where the roots of the characteristic equation are non-zero real numbers that are positively regressive on the time scale,we establish that the best HUS constant in this case is the reciprocal of the absolute product of these two *** for instability are also given.

关键词： stability second order Hyers-Ulam time scales

Interval oscillation criteria for forced Emden-Fowler functional dynamic equations with oscillatory potential

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Science China Mathematics 2013年第3期56卷 561-576页

作者： ANDErSON douglas r. SAKEr Samir H. Department of Mathematics and Computer Science Concordia College Department of Mathematics Faculty of Science Mansoura University

Interval oscillation criteria are established for a second-order functional dynamic equation of Emden-Fowler type with oscillatory potential by applying riccati and generalized riccati techniques. The results represent further improvements on those given even for differential and difference equations. Some examples are considered to illustrate the main results.

关键词： oscillation forced dynamic equations time scales functional equations riccati technique

Parallel boron nitride nanoribbons and etch tracks formed through catalytic etching

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Nano research 2018年第9期11卷 4874-4882页

作者： Armin Ansary Mohsen Nasseri Mathias J. Boland douglas r. Strachan Department of Physics &Astronomy University of Kentucky Lexington KY40506 USA

One-dimensional （1D） catalytic etching was investigated in few-layer hexagonal boron nitride （hBN） films. Etching of hBN was shown to share a number of similarities with that of graphitic films. As in graphitic films, etch tracks in hBN commenced at film edges and occurred predominantly along certain crystal directions of its lattice, though it was shown that the tracks were generally narrower than those of few-layer graphene under similar processing conditions. It was also shown that catalytic hydrogenation can occur completely through a few-layer hBN film, demonstrating that this process can be used in the formation of isolated low-dimensional nanoscale structures from other layered 2D materials beyond graphene. This ability for thin hBN films to be etched completely through allowed for a crystalline substrate to guide the etching process, which was demonstrated with the successful etch track formation of few-layer hBN on single-crystalline sapphire substrates. The substrate-guided etching resulted in parallel few-layer hBN nanoribbons having an average width of 32 nm and spacing of 13 nm.

关键词： hexagonal(hBN) one-dimensional catalytic etching hydrogenation etch tracks nanoribbons

High Performance ring Oscillators from 10-nm Wide Silicon Nanowire Field-Effect Transistors

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Nano research 2011年第10期4卷 1005-1012页

作者： ruo-Gu Huang douglas Tham Dunwei Wang James r. Heath Department of Electrical Engineering Calilfomia Institute of Technology MC 136-93 Pasadena CA 91125 USA Division of Chemistry and Chemical Engineering California Institute of Technology MC 127-72 Pasadena CA 91125 USA Department of Chemistry Boston College 140 Commonwealth Ave Chestnut Hill Massachusetts 02467 USA

We explore 10-nm wide Si nanowire （SiNW） field-effect transistors （FETs） for logic applications, via the fabrication and testing of SiNW-based ring oscillators. We report on SiNW surface treatments and dielectric annealing, for producing SiNW FETs that exhibit high performance in terms of large on/off-state current ratio （-10s）, low drain-induced barrier lowering （-30 mV） and low subthreshold swing （-80 mV/decade）. The performance of inverter and ring-oscillator circuits fabricated from these nanowire FETs are also explored. The inverter demonstrates the highest voltage gain （-148） reported for a SiNW-based NOT gate, and the ring oscillator exhibits near rail-to-rail oscillation centered at 13.4 MHz. The static and dynamic characteristics of these NW devices indicate that these SiNW-based FET circuits are excellent candidates for various high-performance nanoelectronic applications.

关键词： Silicon nanowire (SiNW) field-effect transistor (FET) surface treatment inverter ring oscillator

Forests,atmospheric water and an uncertain future: the new biology of the global water cycle

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Forest Ecosystems 2018年第3期5卷 236-257页

作者： douglas Sheil Faculty of Environmental Sciences and Natural resource Management(MINA) Norwegian University of Life Sciences (NMBU)

Theory and evidence indicate that trees and other vegetation influence the atmospheric water-cycle in various *** influences are more important, more complex, and more poorly characterised than is widely *** there is little doubt that changes in tree cover will impact the water-cycle, the wider consequences remain difficult to predict as the underlying relationships and processes remain poorly characterised. Nonetheless, as forests are vulnerable to human activities, these linked aspects of the water-cycle are also at risk and the potential consequences of large scale forest loss are severe. Here, for non-specialist readers, I review our knowledge of the links between vegetation-cover and climate with a focus on forests and rain(precipitation). I highlight advances, uncertainties and research opportunities. There are significant shortcomings in our understanding of the atmospheric hydrological cycle and of its representation in climate models. A better understanding of the role of vegetation and tree-cover wil reduce some of these shortcomings. I outline and il ustrate various research themes where these advances may be *** themes include the biology of evaporation, aerosols and atmospheric motion, as well as the processes that determine monsoons and diurnal precipitation cycles. A novel theory—the ‘biotic pump’—suggests that evaporation and condensation can exert a major influence over atmospheric dynamics. This theory explains how high rainfall can be maintained within those continental land-masses that are sufficiently forested. Feedbacks within many of these processes can result in non-linear behaviours and the potential for dramatic changes as a result of forest loss(or gain): for example, switching from a wet to a dry local climate(or visa-versa). Much remains unknown and multiple research disciplines are needed to address this: forest scientists and other biologists have a major role to *** ideas, methods and data offer opportun

关键词： Biotic pump Climate Condensation Evaporation Ice-nucleation Transpiration GCM Vapour Water-cycle

The hamster egg penetration test may decrease intracytoplasmic sperm injection utilization while maintaining high conventional fertilization rates

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Asian Journal of Andrology 2021年第1期23卷 11-15页

作者： Yetunde Ibrahim Brett Einerson douglas T Carrell Benjamin r Emery Erica Johnstone Division of reproductive Endocrinology and Infertility Department of Obstetrics and GynecologyUniversity of UtahSchool of MedicineSalt Lake CityUT 84132USA Division of Maternal-Fetal Medicine Department of Obstetrics and GynecologyUniversity of UtahSchool of MedicineSalt Lake CityUT 84132USA Division of Urology Department of SurgeryUniversity of UtahSchool of MedicineSalt Lake CityUT 84132USA Department of Human Genetics University of UtahSchool of MedicineSalt Lake CityUT 84132USA

This was a cohort study of in vitro fertilization(IVF)subjects at the University of Utah,Salt Lake City(UT,USA)utilizing partner *** where both the hamster egg penetration test(HEPT)and semen analysis were performed within 2 years prior to IVF cycles were stratified into four groups based on a normal or an abnormal HEPT and *** mean conventional and intracytoplasmic sperm injection(ICSI)fertilization rates were calculated in each *** performed a univariate analysis on the primary outcome comparing clinically interesting *** performed a cost-effectiveness analysis of a policy of HEPT versus universal ICSI in couples with an abnormal *** patients with a normal HEPT,there was no difference in the mean conventional fertilization rates between those with a normal and an abnormal *** was no difference in the mean conventional fertilization rates between subjects with a normal morphology without a hamster test and those with a normal HEPT without a morphology *** 1000 simulated cycles with an abnormal morphology,a policy of HEPT was cost saving compared to universal ICSI,yet produced similar fertilization *** HEPT is similar to the World Health Organization edition 5(WHO-5)morphology in predicting successful conventional fertilization while allowing decreased utilization of ICSI.A policy of HEPT for males with abnormal morphology saves cost in selecting couples for a fertilization method.

关键词： conventional fertilization hamster egg penetration test intracytoplasmic sperm injection semen analysis sperm penetration assay

Diphosphine-induced chiral propeller arrangement ofgold nanoclusters for singlet oxygen photogeneration

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Nano research 2018年第11期11卷 5787-5798页

作者： Jiangwei Zhang Yang Zhou KaiZheng Hadi Abroshan douglas r. Kauffman Junliang Sun Gao Li State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China University of Chinese Academy of Sciences Beijing 100049 China SUNCAT Center for Interface Science and Catalysis Department of Chemical Engineering Stanford University 443 Via Ortegc~ StanfordCalifornia 94305 USA National Energy Technology Laboratory (NETL) United States Department of Energy Pittsburgh Pennsylvania 15236 USA Beijing National Laboratory for Molecular Sciences State Key Laboratory of Rare Earth Materials Chemistry and Applications College ot Chemistry and Molecular Engineering Peking University Beijing 100871 China

In this study, 1,2-bis(diphenylphosphino)ethane (dppe) ligands are used to synthesize gold nanoclusters with an icosahedral Au-13 core. The nanoclusters are characterized and formulated as [Au-13(dppe)5Cl(2)]Cl-3 using synchrotron radiation X-ray diffraction, UV/Vis absorption spectroscopy, electrospray ionization mass spectrometry, and density functional theory (DFT) calculations. The bidentate feature of dppe ligands and the positions of coordinating surface gold atoms induce a helical arrangement that forms a propeller-like structure, which reduces the symmetry of the gold nanocluster to C-1. Therefore, dppe ligands perform as a directing agent to create chiral an ansa metallamacrocycle [Au-13(dppe)(5)Cl-2](3+) nanocluster, as confirmed by simulated electronic circular dichroism spectrum. The highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap of the [Au-13(dppe)(5)Cl-2](3+) cluster is determined as approx. 1.9 eV, and further confirmed by ultraviolet photoemission spectroscopy analysis and DFT simulation. Furthermore, the photoactivity of [Au-13(dppe)(5)Cl-2](3+) is investigated, with the nanocluster shown to possess near-infrared photoluminescence properties, which can be employed for O-1(2) photogeneration. The quantum yield of O-1(2) photogeneration using the [Au-13(dppe)(5)Cl-2](3+) nanocluster is up to 0.71, which is considerably higher than those of anthracene (an organic dye), and Au-25 and Au-38 nanoclusters.

关键词： gold nanoclusters Au-13 chirality singlet oxygen synchrotron radiation X-ray diffraction (XrD)

Materials and technology of Chinese jades dating to the Western Zhou period (1050―771 BCE)

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Science China(Technological Sciences) 2008年第4期51卷 467-480页

作者： Janet G douglas Department of Conservation and Scientific research Freer Gallery of Art / Arthur M. Sackler Gallery Smithsonian Institution

Excavated jades dating to the Western Zhou period (1050―771 BCE) from the Xi’an area in Shaanxi Province, China, and contemporaneous jades in the collections of the Arthur M. Sackler Gallery at the Smithsonian Institution have been studied to learn about the jade and stone materials and how they were worked during the Western Zhou period. Materials identification was carried out using a combination of techniques such as Fourier-transform infrared spectroscopy and X-ray diffraction. Tool marks were studied using stereomicroscopy and examination of mold impressions using scanning electron microscopy. All of these objects were pro- duced through simple processes involving solid drilling, riffling, and sharp point abrasion; and no evidence was found for the use of rotary tools for incising or sawing.

关键词： jade nephrite stone China Western Zhou scanning electron microscopy materials technology tool marks