Rosa Malena Fernandes Lima, José Aurélio Medeiros da Luz,
... diâmetro equivalente, determinado pelos métodos que utilizam a lei de Stokes, aplicada em regime laminar. Equipamentos mais modernos, como ...
Tópico(s): Chemistry Education and Research
2001 - SciELO | Rem Revista Escola de Minas
Produção Nacional
Revisado por pares
Carlos Maurício Fontes Vieira, Luiz Augusto Hernadez Terrones, R. Sánchez, Sérgio Neves Monteiro,
... foi obtida por técnica de sedimentação baseada na lei de Stokes e submetida à caracterização mineralógica, química e morfológica ...
Tópico(s): Clay minerals and soil interactions
2007 - Associação Brasileira de Cerâmica | Cerâmica
Produção Nacional
Leandro de Oliveira Pereira, Douglas Ferreira, Renato Pereira de Freitas, André Rocha Pimenta, Valter S. Felix, Elicardo Alves de Souza Gonçalves, R. S. Dutra,
Neste trabalho apresentamos uma atividade de baixo custo que visa a investigação da força de arrasto, que atua na geometria de um disco, através das oscilações amortecidas de um sistema massa-mola. Utilizando discos de papelão de diferentes raios e controlando a massa do sistema oscilatório, mantendo-a fixa, estudamos a influência da variação exclusiva da magnitude da força de arrasto na dinâmica desse sistema, por meio da variação do raio do disco, mantendo todos os outros parâmetros acessíveis ...
Tópico(s): Polymer Nanocomposites and Properties
2021 - SOCIEDADE BRASILEIRA DE FÍSICA | Revista Brasileira de Ensino de Física
Produção Nacional
Revisado por pares
Antônio Marcos de Oliveira Siqueira, Abderrahmane Khechekhouche, Júlio César Costa Campos, Gabriel Siqueira Silva, Marlons Lino da Cruz,
Este trabalho teve como objetivo contribuir com estudos sobre a elaboração e a implementação de propostas de atividade didática baseada em experimento de cunho investigativo. O trabalho descreve um experimento com fins acadêmicos para a determinação da massa específica e da viscosidade dinâmica de um fluido por meio do Método de Stokes, um procedimento experimental simples e de baixo custo e que possibilita o processo de ensino/aprendizagem de conceitos diversos da área de Mecânica dos Fluidos, ...
Tópico(s): Chemistry Education and Research
2022 - UNIVERSIDADE FEDERAL DE VIÇOSA | The Journal of Engineering and Exact Sciences
Lei Chen, Taishan Hu, Zhu‐Jun Yao,
Abstract Small, organic, fluorescent molecules with large Stokes shifts and long emission wavelengths are ideal dyes for various modern fluorescent imaging technologies such as FRET. In this study, we designed and synthesized a number of new fluorescent molecules on the basic structures of two pyrrolocoumarin skeletons where Fischer's indole synthesis and the Suzuki coupling successfully served as the efficient molecular editing protocols. The examination of the fluorescent properties and further ...
Tópico(s): Fluorine in Organic Chemistry
2008 - Wiley | European Journal of Organic Chemistry
Paul Stokes, Liwei Liu, Jianhua Zou, Lei Zhai, Qun Huo, Saiful I. Khondaker,
We present a near IR photoresponse study of large area multiwalled carbon nanotube/poly(3-hexylthiophene)-block-polystyrene polymer (MWNT/P3HT-b-PS) nanocomposite films for different loading ratio of MWNT into the polymer matrix. We show that the photocurrent strongly depends on the position of the laser spot with maximum photocurrent occurring at the metal-film interface. In addition, compared to the pure MWNT film, the photoresponse is much larger in the MWNT/polymer composite films. The time constant ...
Tópico(s): Transition Metal Oxide Nanomaterials
2009 - American Institute of Physics | Applied Physics Letters
Hui Chen, Harish Muthuraman, Paul Stokes, Jianhua Zou, Xiong Liu, Jinhai Wang, Qun Huo, Saiful I. Khondaker, Lei Zhai,
We herein report the dispersion of multi-walled carbon nanotubes (MWCNTs) using trifluoroacetic acid (TFA) as a co-solvent. TFA is a strong but volatile acid which is miscible with many commonly used organic solvents. Our study demonstrates that MWCNTs can be effectively purified and readily dispersed in a range of organic solvents including dimethyl formamide (DMF), tetrahydrofuran (THF), and dichloromethane when mixed with 10 vol.% trifluoroacetic acid (TFA). X-ray photoelectron spectroscopic analysis ...
Tópico(s): Advanced Sensor and Energy Harvesting Materials
2007 - IOP Publishing | Nanotechnology
Xingjiang Liu, Long He, Liu Yang, Yani Geng, Lei Yang, Xiangzhi Song,
A highly sensitive and selective fluorescence probe for H2O2 has been developed based on an iminocoumarin derivative using aromatic boronic ester as sensing unit. A significant fluorescence enhancement was observed with λmaxem = 619 nm when this probe was treated with H2O2. In the detection of H2O2, this probe exhibited a large Stokes shift (148 nm) and a low detection limit (6.0 × 10−8 mol/L). Furthermore, cell imaging studies had revealed that this probe had the potential to detect intracellular H2O2 ...
Tópico(s): Luminescence and Fluorescent Materials
2017 - Elsevier BV | Sensors and Actuators B Chemical
Xingjiang Liu, Huihui Tian, Lei Yang, Yuanan Su, Man Guo, Xiangzhi Song,
Using aromatic boronic ester as sensing unit, a red-emitting fluorescent probe, 1, for H2O2 detection has been developed based on an ESIPT fluorescent dye, 4 (1,3-bis(bispyridin-2-ylimino)isoindolin-4-ol). The aromatic boronic ester moiety masked the hydroxy group in dye 4 to inhibit the ESIPT process and quench its fluorescence. The addition of H2O2 cleaved the sensing group in Probe 1 and subsequently resulted in the formation of fluorescent dye 4. This probe displayed a large Stokes shift (217 ...
Tópico(s): Sulfur Compounds in Biology
2017 - Elsevier BV | Sensors and Actuators B Chemical
Lei Yang, Haiqing Xiong, Yuanan Su, Huihui Tian, Xingjiang Liu, Xiangzhi Song,
In this work, we presented a fluorescent probe (MCQ-DNBS) for selective and sensitive detection of biothiols based on a methylated chromenoquinoline (MCQ) derivative. Probe MCQ-DNBS was constructed by masking the OH group in MCQ with a common sensing unit, 2,4-dinitrobezensulfonate group (DNBS) for biothiols. Due to the photo-induced electron transfer (PET) process between MCQ and DNBS, this probe was weekly fluorescent. Upon the addition of biothiols (Cys, Hcy and GSH), this probe emitted a strong red ...
Tópico(s): Lanthanide and Transition Metal Complexes
2018 - Elsevier BV | Chinese Chemical Letters
Produção Nacional
Wagner Costa Cattaneo, Nina Simone Vilaverde Moura,
... com base na escala de Wentworth e a Lei de Stokes, bem como o uso de ferramentas de sensoriamento ...
Tópico(s): Geography and Environmental Studies
2021 - PGDesign/UFRGS | Para Onde!?
Adriano Peixoto Leandro, Elbert Valdiviezo Viera,
... com capacidade de 500 mL, utilizando-se da Lei de Stokes para determinar o grau de dispersão. Empregando-se ...
Tópico(s): Geography and Environmental Studies
2022 - Brazilian Journal of Development | Brazilian Journal of Development
Produção Nacional
Nelsi Santos Dal Cortivo, Ismael Laurindo Costa, Adelmo Lowe Pletsch,
... a metodologia de Gee e Bauder (1986) e Lei de Stokes, com predomínio de solos de texturas argilosa e ...
Tópico(s): Clay minerals and soil interactions
2024 - UNIVERSIDADE FEDERAL DE PERNAMBUCO | Revista Brasileira de Geografia Física
Lei Yang, Yuanan Su, Zhankui Sha, Yani Geng, Fengpei Qi, Xiangzhi Song,
A red-emitting fluorescent probe was developed for the sensitive and selective detection of H2S. Upon treatment with H2S, this probe exhibited a remarkable fluorescence enhancement (10 fold) with a large Stokes shift (125 nm). The detection limit of this probe was as low as 5.7 nM based on S/N = 3. The application of this probe in the detection of intracellular H2S in living cells is successfully demonstrated.
Tópico(s): Luminescence and Fluorescent Materials
2018 - Royal Society of Chemistry | Organic & Biomolecular Chemistry
Song Chen, Peng Hou, Jing Wang, Shuang Fu, Lei Liu,
We have successfully developed a new green-emitting H2S fluorescence probe employing a 2,4-dinitrophenyl ether moiety as the sensing group based on 3'-formyl-4'-hydroxybiphenyl-4-carbonitrile. This probe displayed a rapid (2 min), sensitive (the detection limit was 0.18 μM) and selective with a large Stokes shift (183 nm) in response to H2S, which was beneficial for fluorescence sensing and cell imaging studies. Moreover, this probe can qualitatively and quantitatively detect H2S with a good linearity ( ...
Tópico(s): Luminescence and Fluorescent Materials
2018 - Elsevier BV | Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy
Lei Yang, Yuanan Su, Yani Geng, Fengpei Qi, Xiaojie Ren, Fan Zhang, Xiangzhi Song,
Tópico(s): Lanthanide and Transition Metal Complexes
2018 - Elsevier BV | Analytica Chimica Acta
Song Chen, Peng Hou, Jing‐Wen Sun, Haijun Wang, Lei Liu,
By taking advantage of the intramolecular charge transfer (ICT) process, we presented a novel fluorescent probe IPY-SO2 based on imidazo[1,5-α]pyridine derivative for detecting SO32- with a low detection limit (70 nM). Combining its favorable turn-on fluorescence feature (75-fold), rapid response (5 min), high selectivity, large Stokes shift (174 nm) and low cytotoxicity, IPY-SO2 was successfully applied to imaging SO32 in living MCF-7 cells and zebrafish.
Tópico(s): Luminescence and Fluorescent Materials
2019 - Elsevier BV | Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy
Yonghua Chen, D. A. Dimitrov, Kai-Zhong Gao, Bradley Miller, Dion Song, Jiao-Ming Qiu, Paul Kolbo, Lei Wang, Qing He, M. Covington, Scott Stokes, Victor Sapozhnikov,
We review the 2 Tbit/in 2 reader design landscape based on existing knowledge and projection. We found that the reader signal-to-noise ratio (SNR) requirement will be highly challenging due to the rapid increase in noise and the additional requirements from assisted writing. An acceptable level of channel bit density can be achieved in spite of a slow head-to-media spacing (HMS) reduction provided that both the shield-to-shield (SS) spacing and the ¿a¿ parameter scale with the bit length. We expect ...
Tópico(s): Magnetic and transport properties of perovskites and related materials
2010 - IEEE Magnetics Society | IEEE Transactions on Magnetics
Abstract In this paper, we study the long time decay of global solution to the 3D incompressible Navier-Stokes equations. We prove that if u ∈ C ( R + , X − 1 , σ ( R 3 ) ) u\in {\mathcal{C}}\left({{\mathbb{R}}}^{+},{{\mathcal{X}}}^{-1,\sigma }\left({{\mathbb{R}}}^{3})) is a global solution to the considered equation, where X i , σ ( R 3 ) {{\mathcal{X}}}^{i,\sigma }\left({{\mathbb{R}}}^{3}) is the Fourier-Lei-Lin space with parameters i = − 1 i=-1 and σ ≥ − 1 \sigma \ge -1 , then ‖ u ( t ) ‖ X − 1 , σ \Vert u\left(t){\Vert }_{{{\mathcal{X}}}^{-1,\sigma }} decays ...
Tópico(s): Stability and Controllability of Differential Equations
2021 - De Gruyter Open | Open Mathematics
Lei Yang, Yuanan Su, Yani Geng, Haiqing Xiong, Jinliang Han, Fang Qian, Xiangzhi Song,
A vinethene-based fluorescent probe has been developed for the sensitive and selective detection of Hg 2+ with a low detection limit, a red emission and a large Stokes shift. The probe has been successfully applied to detect Hg 2+ in aqueous solutions, living cells and organisms.
Tópico(s): Sulfur Compounds in Biology
2018 - Royal Society of Chemistry | Organic & Biomolecular Chemistry
Long He, Xingjiang Liu, Yun Zhang, Lei Yang, Fang Qian, Yani Geng, Wenqiang Chen, Xiangzhi Song,
Hydrogen peroxide, one of the curial reactive oxygen species, is believed to involve in a wide range of physiological processes. In this work, we designed and synthesized a new fluorescent probe, HKB, for the detection of hydrogen peroxide, by taking advantage of the combination of ICT and ESIPT mechanisms. Different from other benzothiazole-based ratiometric probes, the intramolecular ESIPT process is preserved in probe HKB and the large Stokes shift is remained. Probe HKB displayed significant ...
Tópico(s): Luminescence and Fluorescent Materials
2018 - Elsevier BV | Sensors and Actuators B Chemical
Lijun Tang, Lei Zhou, Xiaomei Yan, Keli Zhong, Xue Gao, Jianrong Li,
A novel fluorescence off-on Hg2+ probe with near-infrared (NIR) emission (680 nm) and a large Stokes shift (240 nm) has been developed. In MeCN/H2O (1/1, v/v, HEPES (N-2-hydroxyethylpiperazine-N-ethane-sulphonic acid) 10 mM, pH = 7.4) solution, (E)-O-(2-(benzo[d]thiazol-2-yl)-4-(2-(3-(dicyanomethylene)-5,5-dimethylc-yclohex-1-en-1-yl)vinyl)-6-methylphenyl)-O-phenyl carbonothioate (HBTD-M) can detect Hg2+ with high selectivity and sensitivity. The sensing mechanism is based on Hg2+-triggered cleavage of carbonothioate ...
Tópico(s): Analytical Chemistry and Sensors
2019 - Elsevier BV | Journal of Photochemistry and Photobiology A Chemistry
Wei Shen, Lei Wang, Shen Zhu, Shian Yu, Chunhui Cai, Wenjun Yi, Qing Zhu,
Intracellular pH plays an important role in various biological processes; abnormal pH changes in the intracellular compartment leads to the production of free radicals, the disruption of membrane contractility, inappropriate apoptosis, and necrosis, resulting in serious illness. Although fluorescent probes have widely been used to detect pH levels owing to their high sensitivity and specificity, there is still a demand for near-infrared (NIR) fluorescent probes with high Stokes shift. Here, a NIR ...
Tópico(s): Analytical Chemistry and Sensors
2020 - Elsevier BV | Analytical Biochemistry
Xiaochun Sun, Gaoting Xu, Yulian Wu,
Abstract In this article, we researched the existence of the solution to the fractional Navier-Stokes equations with the Coriolis force under initial data, which belong to the Lei-Lin-Gevrey spaces. Moreover, we showed a blow-up criterion, i.e., when the maximal time of existence T * {T}^{* } is finite, we proved that the norm of this same solution, in a specific Lei-Lin-Gevrey space, goes to infinity, as time tends to the maximal time of its existence.
Tópico(s): Nonlinear Partial Differential Equations
2023 - De Gruyter Open | Open Mathematics
Yihuan Zhao, Kuan Chen, Lei Zhu, Qiang Huang,
Organic fluorescent materials are widely used in various fields, including OLEDs, organic solar cells, and bio-imaging. However, designing and synthesizing new fluorescent organic materials with desirable properties for specific applications require knowledge of the chemical and physical properties of previously studied molecules. One critical property of fluorescent organic compounds is the Stokes shift, which is usually measured experimentally and is known to be time-consuming. Time-dependent ...
Tópico(s): Computational Drug Discovery Methods
2023 - Elsevier BV | Dyes and Pigments
Produção Nacional
Revisado por pares
Cla Duri Tschannen, Martin Frimmer, Georgy Gordeev, Thiago L. Vasconcelos, Lei Shi, Thomas Pichler, Stephanie Reich, Sebastian Heeg, Lukáš Novotný,
We investigate the anti-Stokes Raman scattering of single carbyne chains confined inside double-walled carbon nanotubes. Individual chains are identified using tip-enhanced Raman scattering (TERS) and heated by resonant excitation with varying laser powers. We study the temperature dependence of carbyne's Raman spectrum and quantify the laser-induced heating based on the anti-Stokes/Stokes ratio. Due to its molecular size and its large Raman cross section, carbyne holds great promise for local temperature ...
Tópico(s): Graphene research and applications
2021 - American Chemical Society | ACS Nano
Yingjie Zhao, Yuchen Qiu, Jiangang Feng, Jia‐Hui Zhao, Gaosong Chen, Hanfei Gao, Yuyan Zhao, Lei Jiang, Yuchen Wu,
Structural engineering in multiple scales permits the integration of exotic properties into a single material, which boosts the development of ultracompact multifunctional devices. Layered perovskites are capable of cross-linking efficient carrier transport originating from few-layer perovskite frameworks with extended functionalities contributed by designable bulky organic cations and nanostructures, thus providing a platform for multiscale material engineering. Herein, high-performance Stokes- ...
Tópico(s): Multiferroics and related materials
2021 - American Chemical Society | Journal of the American Chemical Society
Yanmeng Dai, Yuquan Zhang, Youpeng Xie, Dapeng Wang, Xianyou Wang, Ting Lei, Changjun Min, Xiaocong Yuan,
Polarization imaging finds applications in many areas, such as photoelasticity, ellipsometry, and biomedical imaging. A compact, snapshot, and high-efficiency imaging polarimeter is highly desirable for many applications. Here, based on a single multifunctional geometric phase optical element (GPOE), a new method is proposed for high-efficiency snapshot imaging polarimetry. With tailored spatially varying orientation of each anisotropic unit cell, the GPOE works highly efficiently as both a spin ...
Tópico(s): Optical Polarization and Ellipsometry
2019 - Optica Publishing Group | Photonics Research
Lei Zhang, Zhisong Huang, Dongdong Dai, Yansheng Xiao, Kecheng Lei, Shaoying Tan, Jiagao Cheng, Yufang Xu, Jianwen Liu, Xuhong Qian,
By structure transformation of benzo[k,l]thioxanthene-naphthalimide derivatives (ND-S), a novel series of nonplanar thio-heterocyclic bisnaphthalimide derivatives are designed and synthesized. They display high molar absorptivity and large Stokes shifts. They are also heavy-atom-free photosensitizers with high singlet oxygen quantum yields of 0.75 and 0.82. Thus, these new structures based on the naphthalimide skeleton have great potential for singlet oxygen applications.
Tópico(s): Perovskite Materials and Applications
2016 - American Chemical Society | Organic Letters