137,553 research outputs found
Complete structural characterization of single carbon nanotubes by Rayleigh scattering circular dichroism
No full textFunding Information: This work was supported by the National Natural Science Foundation of China under grant numbers 52021006 (J. Zhang), 52025023 (K.L.) and 51991342 (K.L.); the Key R&D Programme of Guangdong Province with grant numbers 2020B010189001 (K.L.), 2019B010931001 (K.L.) and 2018B030327001 (K.L.); the National Key R&D Programme of China under grant numbers 2016YFA0300903 (K.L.), 2017YFA0303800 (K.L.) and 2016YFA0300804 (P.G.); the Strategic Priority Research Programme of Chinese Academy of Sciences with grant number XDB33000000 (K.L.); Beijing Natural Science Foundation under grant number JQ19004 (K.L.); Beijing Graphene Innovation Programme under grant number Z181100004818003 (K.L.); the Pearl River Talent Recruitment Programme of Guangdong Province with grant number 2019ZT08C321 (K.L.); National Equipment Programme of China under grant number ZDYZ2015-1 (X.B.); National Postdoctoral Programme for Innovative Talents under award number BX20190016 (C.L.) and China Postdoctoral Science Foundation under award numbers 2019M660280 (C.L.) and 2019M660281 (R.Q.). Publisher Copyright: © 2021, The Author(s), under exclusive licence to Springer Nature Limited.Non-invasive, high-throughput spectroscopic techniques can identify chiral indices (n,m) of carbon nanotubes down to the single-tube level1–6. Yet, for complete characterization and to unlock full functionality, the handedness, the structural property associated with mirror symmetry breaking, also needs to be identified accurately and efficiently7–14. So far, optical methods fail in the handedness characterization of single nanotubes because of the extremely weak chiroptical signals (roughly 10−7) compared with the excitation light15,16. Here we demonstrate the complete structure identification of single nanotubes in terms of both chiral indices and handedness by Rayleigh scattering circular dichroism. Our method is based on the background-free feature of Rayleigh scattering collected at an oblique angle, which enhances the nanotube’s chiroptical signal by three to four orders of magnitude compared with conventional absorption circular dichroism. We measured a total of 30 single-walled carbon nanotubes including both semiconducting and metallic nanotubes and found that their absolute chiroptical signals show a distinct structure dependence, which can be qualitatively understood through tight-binding calculations. Our strategy enables the exploration of handedness-related functionality of single nanotubes and provides a facile platform for chiral discrimination and chiral device exploration at the level of individual nanomaterials.Peer reviewe
Agent Angus by K.L. Denman
No full textDenman, K.L. Agent Angus. Victoria: Orca Book Publishers, 2012. Print. An Orca Currents book for reluctant middle school readers, the story follows Angus and his best friend Shahid on their mission to solve a mysterious theft. Canadian author K.L. Denman writes in her usual first-person narrative style with characteristic elements of mystery, science and romance. The story takes place at a school where a stink bomb incident has led to all the students gathering on the front lawn. Right from the book’s introduction (“I’m not a lucky guy. Today luck has chosen to place me next to the one and only Ella Eckles”), readers are taken inside Angus’ head and will be rooting for him along the way. When his crush’s cherished sketchbook goes missing, Angus poses as a mentalist who can solve the crime by reading people. He ‘proves’ his abilities to Ella by pointing out the shifty stink bomb perpetrator right before he is nabbed by the principal. Humorous elements run throughout such as when the boys consider various spy devices (Gordon the ‘too obvious’ robot, a rocket pack launched from a plane, pricey video cameras hidden in smiley face buttons or baseball hats which are not allowed in school, and affordable but oversized rear view sunglasses). Suspense builds as the various suspects are considered. Is the thief their fellow classmate, their art teacher or someone they least suspected? And what could their motive be? This quick read full of spying and intrigue will have readers flipping pages to solve the mystery of the sketchbook and find out if Angus will finally confront the truth. The fluid writing style with varying sentence lengths adds to the drama and pace of the story. This light-hearted story makes a great choice for reluctant readers but lacks deep meaning. It may not appeal to readers who are looking to be challenged. Those looking for a light, easy read will find it enjoyable.Recommended: 3 out of 4 stars Reviewer: Lori Williams Lori Williams has been teaching at Forest Grove School in British Columbia for the past 6 years and feels lucky to be part of a wonderful team of colleagues and students. This year she is teaching grade 5 at Forest Grove and is also a graduate student in the University of Alberta’s Teacher-Librarianship by Distance Learning program
Protecting Animals 36: Author Witi Ihimaera
No full textIn this very special episode of Knowing Animals I am joined by beloved New Zealand author Witi Ihimaera. Witi has written many books featuring nonhuman animals. He offers us a non-colonial lens through which to think about the human/nonhuman relationship
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
Retinitis Pigmentosa GTPase Regulator (RPGR) protein isoforms in mammalian retina:insights into X-linked Retinitis Pigmentosa and associated ciliopathies
No full textMutations in the cilia-centrosomal protein Retinitis Pigmentosa GTPase Regulator (RPGR) are a frequent cause of retinal degeneration. The RPGR gene undergoes complex alternative splicing and encodes multiple protein isoforms. To elucidate the function of major RPGR isoforms (RPGR 1-19 and RPGR ORF15), we have generated isoform-specific antibodies and examined their expression and localization in the retina. Using sucrose-gradient centrifugation, immunofluorescence and co-immunoprecipitation methods, we show that RPGR isoforms localize to distinct sub-cellular compartments in mammalian photoreceptors and associate with a number of cilia-centrosomal proteins. The RCC1-like domain of RPGR, which is present in all major RPGR isoforms, is sufficient to target it to the cilia and centrosomes in cultured cells. Our findings indicate that multiple isotypes of RPGR may perform overlapping yet somewhat distinct transport-related functions in photoreceptors
Investigation of Lagrangian coherent structures in a wake-induced boundary layer transition
No full textThe evolution of coherent structures in a flat plate boundary layer transition induced by the cylinder wake is investigated using the particle image velocimetry (PIV) technique. The finite-time Lyapunov exponent (FTLE), which characterizes the amount of stretching about the flow trajectory, is used to extract the Lagrangian coherent structures. It is revealed that secondary vortex is induced by the cylinder wake vortices in the near wall region,which would evolve into hairpin vortex as it convects downstream. The subsequent evolvement of the hairpin vortex, characterized by the regeneration of offspring hairpin vortex upstream of it, leads to the appearance of the hairpin packet and the boundary layer finally reaches a turbulent state
Taxonomy and nomenclature of Salix baileyi, S. rehderiana, and S. disperma
No full textResearchers have frequently misapplied the name Salix leveilleana C.K. Schneider to S. baileyi C.K. Schneider. After detailed study of the types, relevant specimens and literature, S. leveilleana is synonymized with S. disperma Roxb. ex D. Don. Salix dolia C.K. Schneider and S. rehderiana C.K. Schneider represent the same taxon; in this study, the later one is chosen. Furthermore, the author perfected the descriptions of S. baileyi, and amend its distribution area to include Hunan and Zhejiang, China.</jats:p
Reynolds numbers near the ultimate state of turbulent Rayleigh-Bénard convection
No full textWe report on measurements of the mean-flow Reynolds number ReU and the rms fluctuation Reynolds number ReV in turbulent Rayleigh-Bénard convection as a function of the Rayleigh number Ra for 4 x 1011 < Ra < 2 1014 and Pr ' 0:8. Both can be described by the same power law with an effective exponent = 0:44, in agreement with predictions for ReU but in disagreement with predictions for ReV
The Göttingen rotating turbulent Rayleigh-Bénard convection facility
No full textThermally driven turbulent convection under the influence of global rotation is ubiquitous in nature. Well known examples are the outer convective shell of our Sun and the outer liquid core of the Earth. Trying to understand the underlying dynamics of such flows is highly challenging, not only because of the enormous range in length- and time-scales that are involved with these geo/astrophysical cases and the complex interaction of hydrodynamics with electromagnetism, but also because direct measurements on these systems are most often impossible to carry out. We gain access to direct measurements by isolating part of the problem: We focus solely on the hydrodynamical aspects of turbulent convection by performing experiments in the lab and making comparisons with direct numerical simulations (DNS). The canonical system that we use to study such flows is Rayleigh-B\'enard convection (RBC), the flow between a warm bottom plate and cold top plate, in a fluid-filled upright cylindrical cell that is rotating around its geometrical axis. This presentation will focus on the newly constructed rotating RBC facility at the Max Planck Institute for Dynamics and Self-Organization (MPIDS) in G\"ottingen
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