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Photoluminescence of Ag-In-S/ZnS quantum dots: Ex.itation energy dependence and low-energy electronic structure

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Nano Research 2019年第7期12卷 1595-1603页

作者： Irina V. Martynenko Anvar S. Baimuratov Florian Weigert Jose x. soares Lorena Dhamo Philip Nickl Ilona Doerfel Jutta Pauli Ivan D. Rukhlenko Alex.nder V. Baranov Ute Resch-Genger Federal Institute for Materials Research and Testing (BAM) Unter den Eichen 8712205 BerlinGermany ITMO University 49 Kronverksky Pr.St. Petersburg197101Russia University of Porto Rua de Jorge Viterbo Ferreira2284050-313 PortoPortugal Institute of Photonics and Optical Sciences (IPOS) School of PhysicsThe University of SydneyCamperdown 2006NSWAustralia

Cd-free Ⅰ-Ⅲ-Ⅵ group semiconductor quantum dots (QDs) like Ag-ln-S and Cu-ln-S show unstructured absorption spectra with a pronounced Urbach tail,rendering the determination of their band gap energy (Eg) and the energy structure of the ex.iton ***,the origin of the broad photoluminescence (PL) band with lifetimes of several hundred nanoseconds is still *** encouraged us to study the ex.itation energy dependence (EED) of the PL max.ma,PL spectral band widths,quantum yields (QYs),and decay kinetics of AlS/ZnS QDs of j different size,composition,and surface capping *** results were then correlated with the second derivatives of the corresponding absorption *** ex.ellent match between the onset of changes in PL band position and spectral width with the minima found for the second derivatives of the absorption spectra underlines the potential of the EED approach for deriving Eg values of these ternary QDs from PL *** PL QY is,however,independent of ex.itation energy in the energy range *** the EED of the PL features of the AlS/ZnS QDs we could also derive a mechanism of the formation of the low-energy electronic *** was additionally confirmed by a comparison of the EED of PL data of as-synthesized and size-selected QD ensembles and the comparison of these PL data with PL spectra of single *** results indicate a strong contribution of intrinsic inhomogeneous PL broadening to the overall emission features of AlS/ZnS QDs originating from radiative transitions from a set of energy states of defects localized at different positions within the quantum dot volume,in addition to contributions from dimensional and chemical *** mechanism was confirmed by numerically modelling the absorption and PL energies with a simple mass approx.mation for spherical QDs and a modified donor-acceptor model,thereby utilizing the advantages of previously proposed PL mechanisms of ternary *** findings will

关键词： core/shell quantum dot silver indium sulfide defect photoluminescence photoluminescence quantum yield single-dot spectroscopy

The development of microfabricated solenoids with magnetic cores for micromagnetic neural stimulation

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Microsystems & Nanoengineering 2021年第6期7卷 97-106页

作者： Adam Khalifa Mohsen Zaeimbashi Tony x.Zhou Seyed Mahdi Abrishami Neville Sun Seunghyun Park tamaraŠumarac Jason Qu Inbar Zohar Amir Yacoby Sydney Cash Nian x.Sun Department of Neurology Massachusetts General HospitalHarvard Medical SchoolBostonMAUSA Department of Electrical and Computer Engineering Northeastern UniversityBostonMAUSA Research Laboratory of Electronics Massachusetts Institute of TechnologyCambridgeMAUSA Department of Physics Harvard UniversityCambridgeMAUSA Department of Chemical and Biological Physics Weizmann Institute of ScienceRehovotIsrael

Electrical stimulation via invasive microelectrodes is commonly used to treat a wide range of neurological and psychiatric *** its remarkable success,the stimulation performance is not sustainable since the electrodes become encapsulated by gliosis due to foreign body *** stimulation overcomes these limitations by eliminating the need for a metal-electrode ***,we demonstrate a novel microfabricated solenoid inductor(80µm×40µm)with a magnetic core that can activate neuronal *** characterization and proof-of-concept of the device raise the possibility that micromagnetic stimulation solenoids that are small enough to be implanted within the brain may prove to be an effective alternative to ex.sting electrode-based stimulation devices for chronic neural interfacing applications.

关键词： magnetic neural overcome

Resource discovery in distributed digital libraries through visual knowledge navigation

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2005年第11期6卷 1306-1311页

作者： AHMAD Faisal SUMNER tamara Department of Computer Science University of Colorado Colorado 80309-0430 USADepartment of Computer Science University of Colorado Colorado 80309-0430 USA

In order to support users to search and browse for various resources, digital libraries are composed of discovery systems which provide user interface and information retrieve system. Recent researches in Information Retrieval have investi- gated different techniques through improving precision and recall to enhance the effectiveness of discovery system in digital libraries. In this paper, we present our work to enhance discovery system effectiveness with a different approach, through resource discovery based on visual knowledge navigation. In our Strand Map Services project under National Science Digital Library, we introduce the visual resource discovery system called conceptual browsing interfaces, to help educators and learners to locate, comprehend and use educational resources in digital libraries. The paper begins with a short introduction of the Strand Map Services. Then we illustrate the service architecture, the design and implementation of its major components. We will focus our discussion of how the visualization system of the Strand Map Services supports the visual knowledge navigation for distributed digital libraries. This includes the knowledge acquisition of the conceptual browsing interfaces, different knowledge representa- tions in the system perspective and user interface perspective, visualization system modules, algorithm and Web services inte- gration to use visual knowledge navigation to enhance resource discovery in digital libraries.

关键词： Discovery system Digital libraries Visualization Concept space Web services

SOME FURTHER NOTES ON THE MATRIx.EQUATIONS A^Tx.+B^Tx.TA=C AND A^Tx.+B^Tx.=C

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Acta Mathematica Scientia 2015年第1期35卷 275-280页

作者： G.soares Center of Mathematics University of Trás-os-Montes of Alto Douro

Dehghan and Hajarian, [4], investigated the matrix.equations A^Tx.＋B^Tx.TA = C and A^Tx. ＋ B^Tx. = C providing inequalities for the determinant of the solutions of these equations. In the same paper, the authors presented a lower bound for the product of the eigenvalues of the solutions to these matrix.equations. Inspired by their work, we give some generalizations of Dehghan and Hajarian results. Using the theory of the numerical ranges, we present an inequality involving the trace of C when A, B, x.are normal matrices satisfying A^T B = BA^T.

关键词： matrix.equation eigenvalue trace permutation matrix

Improved Feistel-based ciphers for wireless sensor network security

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第8期9卷 1111-1117页

作者： tamara PAZYNYUK George S. OREKU Department of Computer Science and Engineering Harbin Institute of TechnologyHarbin 150006 China

Wireless sensor networks (WSNs) are ex.osed to a variety of attacks. The quality and complex.ty of attacks are rising day by day. The proposed work aims at showing how the complex.ty of modern attacks is growing accordingly, leading to a similar rise in methods of resistance. Limitations in computational and battery power in sensor nodes are constraints on the diversity of security mechanisms. We must apply only suitable mechanisms to WSN where our approach was motivated by the application of an improved Feistel scheme. The modified accelerated-cipher design uses data-dependent permutations, and can be used for fast hardware, firmware, software and WSN encryption systems. The approach presented showed that ciphers using this approach are less likely to suffer intrusion of differential cryptanalysis than currently used popular WSN ciphers like DES, Camellia and so on.

关键词： Security Cipher Wireless sensor network (WSN) Feistel scheme

Rationally designed synthesis of bright AgInS2/ZnS quantum dots with emission control

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Nano Research 2020年第9期13卷 2438-2450页

作者： Jose x.soares K.David Wegner David S.M.Ribeiro Armindo Melo Ines Hausler Joao L.M.Santos Ute Resch-Genger LAQV-REQUIMTE Department of Chemical SciencesLaboratory of Applied ChemistryFaculty of PharmacyUniversity of PortoRua de Jorge Viterboferreira228Porto4050-313Portugal Federal Institute for Materials Research and Testing(BAM) Division BiophotonicsRichard-Willstaetter-Strasse 1112489 BerlinGermany LAQV-REQUIMTE Laboratorio de Bromatologia e HidrologiaDepartamento de Ciencias QutmicasFaculdade de Farmacia da Universidade do PortoRua de Jorge Viterboferreira228Porto4050-313Portugal Technische Universitat Berlin Institutfiir Optik und Atomare PhysikStrafie des 17.Juni 13510623 BerlinGermany

In the blossoming field of Cd-free semiconductor quantum dots(QDs),ternary Ⅰ-Ⅲ-VI QDs have received increasing attention due to the ease of the environmentally friendly synthesis of high-quality materials in water,their high photoluminescence(PL)quantum yields(QYs)in the red and near infrared(NIR)region,and their inherently low ***,their ox.gen-insensitive long PL lifetimes of up to several hundreds of nanoseconds close a gap for applications ex.loiting the compound-specific parameter PL *** overcome the lack of reproducible synthetic methodologies and to enable a design-based control of their PL properties,we assessed and modelled the synthesis of high-quality MPA-capped AglnS2/ZnS(AlS/ZnS)*** refined parameters included reaction time,temperature,Ag:In ratio,S:In ratio,Zn:In ratio,MPA:ln ratio,and pH using a design-of-ex.eriment *** for the optimization was provided by mathematical models developed for the application-relevant PL parameters,max.mum PL wavelength,QY,and PL lifetime as well as the elemental composition in terms of Ag:ln:Zn *** these ex.erimental data-based models,MPA:ln and Ag:ln ratios and pH values were identified as the most important synthesis parameters for PL control and an insight into the connection of these parameters could be ***,the ex.erimental conditions to synthetize QDs with tunable emission and high QY were *** ex.ellent agreement between the predicted and ex.erimentally found PL features confirmed the reliability of our methodology for the rational design of high quality AlS/ZnS QDs with defined PL *** approach can be straightforwardly ex.ended to other ternary and quaternary QDs and to doped QDs.

关键词： quantum dot core/shell nanoparticle silver indium sulfide microw ave-assisted synthesis design of ex.erim ent photoluminescence

New insights into the regulation of cholesterol eft from the sperm membrane

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Asian Journal of Andrology 2015年第4期17卷 561-567页

作者： tamara Leahy Bart M Gadella Faculty of Veterinary Science University of Sydney 2006 Sydney Australia Department of Farm Animal Health and of Biochemistry and Cell Biology Faculty ofVeterinary Medicine Utrecht University Yalelaan 2 3584 CM Utrecht The Netherlands.

Cholesterol is an essential component of the mammalian plasma membrane because it promotes membrane stability without comprising membrane fluidity. Given this important cellular role, cholesterol levels are tightly controlled at multiple levels. It has been clearly shown that cholesterol redistribution and depletion from the sperm membrane is a key part of the spermatozoon＇s preparation for fertilization. Some factors that regulate these events are described （e.g., bicarbonate, calcium） but the mechanisms underlying cholesterol ex.ort are poorly understood. How does a hydrophobic cholesterol molecule inserted in the sperm plasma membrane enter the energetically unfavorable aqueous surroundings？ This review will provide an overview of knowledge in this area and highlight our gaps in understanding. The overall aim is to better understand cholesterol redistribution in the sperm plasma membrane, its relation to the possible activation of a cholesterol transporter and the role of cholesterol acceptors. Armed with such knowledlze, sl）erm handlin~ techniques can be adapted to better prepare spermatozoa for in vitro and in vivo fertilization.

关键词： ATP binding cassette transporters albumin high-density lipoprotein lipid rafts membrane fluidity membranemicrodomains membrane packing ox.sterols reverse cholesterol transport sterol transporters

Repeated penile girth enhancement with biodegradable scaffolds： microscopic ultrastructural analysis and surgical benefits

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Asian Journal of Andrology 2018年第5期20卷 488-492页

作者： Miroslav L Djordjevic Uros Bumbasirevic Borko Stojanovic tamara Kravic Stevovic tamara Martinovic Marta Bizic Vladimir Kojovic School of Medicine University of Belgrade Belgrade 11000 Serbia University Children's Hospital Belgrade 11000 Serbia Institute for Urology Clinical Center ofSerbia Belgrade 11000 Serbia

Autologous tissue engineering using biodegradable scaffolds as a carrier is a well-known procedure for penile girth enhancement. We evaluated a group of previously treated patients with the aim to analyze histomorphometric changes after tissue remodeling and to estimate the benefits of repeated procedure. Between February 2012 and December 2016, a group of 21 patients, aged 22-37 （mean 28.0） years, underwent a repeated penile girth enhancement procedure with biodegradable scaffolds. Procedure included insertion of two poly-lactic-co-glycolic acid scaffolds seeded with laboratory-prepared fibroblasts from scrotal tissue specimens. During this procedure, biopsy specimens of tissue formed after the first surgery were taken for microscopic analysis. The mean follow-up was 38 months. Connective tissue with an abundance of connective tissue fibers, small blood vessels, and inflammatory cells were observed in all analyzed surgically removed tissue. Ultrastructural analysis of these tissue samples discovered the presence of large quantities of collagen fibrils running parallel to each other, forming bundles, with a few widely spread fibroblasts. In total, the mean values of flaccid and erect gain in girth after the second surgery were 1.1 ± 0.4 （range： 0.6- 1.7） cm and 1.0±0.3 （range： 0.6-1.5） cm, respectively. Microscopic evaluation of newly formed tissue, induced by autologous tissue engineering using biodegradable scaffolds, showed the presence of vascularized loose connective tissue with an abundance of collagen fibers, fibroblasts, and inflammatory cells, indicating active neovascularization and fibrinogenesis. The benefit of the repeated enhancement procedure was statistically significant.

关键词： biodegradable scaffolds microscopy penile enhancement tissue engineering

The coppice-with-standards silvicultural system as applied to Eucalyptus plantations-a review

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Journal of Forestry Research 2014年第2期25卷 237-248页

作者： Antonio Carlos FERRAZ FILHO José Roberto soares SCOLFORO Blas MOLA-YUDEGO Departamento de Ciências Florestais Universidade Federal de Lavras (UFLA) School of Forest Sciences University of Eastern Finland (UEF)

We review the management of Eucalyptus species under a coppice-with-standards （CWS） silvicultural system. CWS management results in product diversification, permitting production of small and large scale timber from the same stand. Eucalyptus species are suitable candidates for CWS management because： there are large worldwide plantation areas, sprouting capacity is high, and eucalypts are multipur- pose species. We discuss （1） short rotation Eucalyptus coppice manage- ment for energy and pulping and （2） Eucalyptus seedling management for solid wood products. We review the literature and discuss ex.eri- ences with Eucalyptus managed under the CWS system. We also assess projects dealing with Eucalyptus coppice management, stand density regulation, pruning, and stand and wood quality. The growth environ- ment of the standard trees （heavy competition up to the first harvest, free growth afterwards） coupled with long rotations （〉20 years） results in high quality logs for solid wood products. Early pruning should be ap- plied to enhance wood quality. We propose a system for the silvicultural management of Eucalyptus under the CWS system, elaborating on the consequences of initial planting density, site productivity, and standard tree densities as well as timing of basic silvicultural applications.

关键词： stand density regulation coppice management pruning silvicultural system stand production diversification CWS