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1.
Nanoscale ; 12(4): 2569-2577, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-31934714

RESUMO

Printable perovskite quantum dot (QD) ink is very important for achieving high quality coffee ring-free fluorescent microarrays for different kinds of emerging perovskite optoelectronic applications using inkjet printing. In this work, we prepared a printable CsPbBr3 perovskite QD ink by mixing high-boiling point dodecane with low-boiling point toluene as a solvent. The evaporation rate, viscosity and surface tension of the ink were carefully optimized by tuning the volume ratio of these two solvents for forming appropriate Marangoni flow, so as to balance the capillary flow and eliminate the coffee ring effect further. Successfully, CsPbBr3 perovskite microarrays with uniform surface, low roughness and no coffee rings were achieved by inkjet printing the optimized perovskite QD ink on a PVK (poly-(9-vinylcarbazole)) layer. Furthermore, we patterned the CsPbBr3 perovskite QD ink, and the printed patterns were only visible under ultraviolet (UV) light, which can be applied in invisible anti-counterfeiting labels and encryption in the future.

2.
Carbohydr Res ; 487: 107882, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31812877

RESUMO

As a new kind of solvent and catalyst, the functionalized ionic liquids (ILs) had been successfully used in the conversion of fructose to high value-added biofuels. In this work, a detailed density functional theory (DFT) calculation had been carried out to investigate the interactions of fructose-ILs system. To study the effect of different anions and cations on the interaction with fructose, 25 different kinds of functionalized imidazolium-based ILs were calculated by using M06-2X-D3/6-311 + G** level. It was found that the interaction energies of fructose-anions were higher than those of the fructose-cations. The interaction will become stronger for the fructose and ILs when the alkyl chain of imidazolium-based cations was replaced with a functional group (COOH, OH or HSO3). However, when the length of the alkyl chain increased, it will result in a decrease in interaction energy due to the steric effect. In the anions (Y-SO3), the greater electronegativity of SO3 will lead to strong interaction with fructose. Also, this work simulates the interaction of fructose and ion pairs, with the results showing that hydrogen bonds (H-bonds) and π-stacking play an important role in the system. The present study provided basic aids to understand the structures and noncovalent interaction of fructose and functionalized ILs as well as the microscopic mechanism of fructose dissolution in the ILs.

3.
Micromachines (Basel) ; 10(11)2019 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-31652696

RESUMO

Flexible pressure sensors have attracted tremendous attention from researchers for their widely applications in tactile artificial intelligence, electric skin, disease diagnosis, and healthcare monitoring. Obtaining flexible pressure sensors with high sensitivity in a low cost and convenient way remains a huge challenge. In this paper, the composite dielectric layer based on the mixture of carbon nanotubes (CNTs) with different aspect ratios and polydimethylsiloxane (PDMS) was employed in flexible capacitive pressure sensor to increase its sensitivity. In addition, the screen printing instead of traditional etching based methods was used to prepare the electrodes array of the sensor. The results showed that the aspect ratio and weight fraction of the CNTs play an important role in improving the sensitivity of the printed capacitive pressure sensor. The prepared capacitive sensor with the CNTs/PDMS composite dielectric layer demonstrated a maximum sensitivity of 2.9 kPa-1 in the pressure range of 0-450 Pa, by using the CNTs with an aspect ratio of 1250-3750 and the weight fraction of 3.75%. The mechanism study revealed that the increase of the sensitivity of the pressure sensor should be attributed to the relative permittivity increase of the composite dielectric layer under pressure. Meanwhile, the printed 3 × 3 and 10 × 10 sensor arrays showed excellent spatial resolution and uniformity when they were applied to measure the pressure distribution. For further applications, the flexible pressure sensor was integrated on an adhesive bandage to detect the finger bending, as well as used to create Morse code by knocking the sensor to change their capacitance curves. The printed and flexible pressure sensor in this study might be a good candidate for the development of tactile artificial intelligence, intelligent medical diagnosis systems and wearable electronics.

4.
Medicine (Baltimore) ; 98(39): e17209, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31574830

RESUMO

BACKGROUND: This study is to summarize the status of knowledge, attitudes, implementation, facilitators, and barriers of evidence-based practice (EBP) in community nurses (CNs). EBP has been widely adopted but the knowledge, attitudes, and implementation of EBP among CNs, and the facilitators and barriers they perceived have not been clearly confirmed. METHODS: A literature search was conducted using combined keywords in 3 English databases and 3 Chinese databases of peer-reviewed publications covering the dates of publication from 1996 to July, 2018. Twenty articles were included. The information of the knowledge, attitudes, implementation, and the perceived facilitators and barriers of EBP in CNs was extracted and summarized. RESULTS: CNs had positive attitudes toward EBP, but insufficient knowledge and unprepared implementation. The most cited facilitators were academic training, management functions, and younger age. Inadequate time and resources were recognized as main barriers hindering the transforming from knowledge and attitudes to implementation. Developed interventions mainly focused on knowledge facilitation rather than the elimination of objective barriers. CONCLUSIONS: Findings demonstrate a compelling need for improvement in knowledge and implementation of EBP in CNs, compared with the better attitudes. Except education, knowledge translating into implementation needs more coordination with authorities to magnify the facilitators and overcome the barriers. Further studies need to concentrate on deficient knowledge and implementation of EBP among CNs. Policy makers can use the facilitators and barriers found by this review to modify nursing education, current scientific resources supplement, practice supports for care improving.


Assuntos
Atitude do Pessoal de Saúde , Prática Clínica Baseada em Evidências , Conhecimentos, Atitudes e Prática em Saúde , Implementação de Plano de Saúde , Enfermeiros de Saúde Comunitária/psicologia , Adulto , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
5.
Nanoscale Res Lett ; 14(1): 197, 2019 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-31172304

RESUMO

Highly conductive ink with low sintering temperature is important for printed electronics on paper substrate. Silver nanoparticles (Ag NPs) of different average radii ranging from 48 to 176 nm were synthesized by adjusting the Ag+ concentration in the reaction process. The electric resistivity of the Ag NP-based ink film in relation to Ag NP size, sintering temperature, amount of PVP capping agent on Ag NP surface, and morphology evolution of the film during heating process was investigated. It was found that the resistivity of the films reduced very rapidly with increasing particle size due above all to reduced amount of protective agent capping on the Ag NPs. A semi-empirical relationship between the resistivity and the particle size was proposed. With the help of this mathematical expression, one gains both systematic and detailed insight to the resistivity evaluation with regard to the Ag particle size. The optimal electric resistivity of 4.6 µΩ cm was achieved at 140 °C for 10 min which was very close to the resistivity value of bulk Ag (1.58 µΩ cm). Mechanical flexibility of the printed electronics with the Ag NP-based ink on paper substrates was investigated. The prints on the art coated paper exhibited better flexibility compared to that on the photopaper. This might be attributed to the surface coating composition, surface morphology of the paper, and their corresponding ink absorption property.

6.
Polymers (Basel) ; 11(1)2018 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-30960006

RESUMO

The thermally expandable microspheres (TEMs) were prepared through suspension polymerization with acrylonitrile (AN), methyl methacrylate (MMA) and methyl acrylate (MA) as the main monomers. Simultaneously, iso-pentane, n-hexane, iso-octane and other low-boiling hydrocarbons were prepared as blowing agents under two conditions, including high-pressure nitrogen and atmospheric conditions. The above physical foaming microspheres have a core-shell structure and excellent foaming effects. A layer of polyaniline (PANI) was deposited on the surface of the prepared TEMs by emulsion polymerization to obtain conductive and heat-expandable microspheres. Afterwards, the foaming ink was prepared by mixing the conductive TEMs and water-based ink. Finally, a conductive three-dimensional picture was obtained by screen-printing technology. This paper specifically focuses on the effects of particle size, morphology and the thermal expansion properties of the microspheres. The present research methods expect to obtain microspheres with a high foaming ratio, uniform particle size and antistatic properties, which may be applied to physical foaming ink.

7.
Environ Sci Technol ; 49(15): 9289-97, 2015 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-26154110

RESUMO

Simultaneous reduction of Cr(VI) to Cr(III) and oxidation of As(III) to As(V) is a promising pretreatment process for the removal of chromium and arsenic from acid aqueous solution. In this work, the synergistic redox conversion of Cr(VI) and As(III) was efficiently achieved in a three-dimensional electrocatalytic reactor with synthesized AuPd/CNTs particles as electrocatalysts. The AuPd/CNTs facilitated the exposure of active Pd{111} facets and possessed an approximate two-electron-transfer pathway of oxygen reduction with the highly efficient formation of H2O2 as end product, resulting in the electrocatalytic reduction of 97.2 ± 2.4% of Cr(VI) and oxidation of 95.7 ± 4% of As(III). The electrocatalytic reduction of Cr(VI) was significantly accelerated prior to the electrocatalytic oxidation of As(III), and the effectiveness of Cr(VI)/As(III) conversion was favored at increased currents from 20 to 150 mA, decreased initial pH from 7 to 1 and concentrations of Cr(VI) and As(III) ranging from 50 to 1 mg/L. The crucial intermediates of Cr(V) and As(IV) and active free radicals HO(•) and O2(•-) were found for the first time, whose roles in the control of Cr(VI)/As(III) redox conversion were proposed. Finally, the potential applicability of AuPd/CNTs was revealed by their stability in electrocatalytic conversion over 10 cycles.


Assuntos
Ácidos/química , Arsênico/química , Cromo/química , Eletroquímica/métodos , Ouro/química , Nanotubos de Carbono/química , Paládio/química , Água/química , Eletricidade , Espectroscopia de Ressonância de Spin Eletrônica , Radicais Livres/química , Peróxido de Hidrogênio , Concentração de Íons de Hidrogênio , Oxirredução , Espectroscopia Fotoeletrônica , Teoria Quântica , Soluções
8.
J Mol Model ; 21(4): 92, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25786832

RESUMO

A density functional theoretical (DFT) method was applied to understand the effects of the substituent on dioxygen activation by a series of substituted iron tetraphenylporphyrins [FeT(o/p-R)PP (o = ortho-substituted, p = para-substituted; R = -H, -Cl, -NO2, -CH3, -OCH3)]. The ground states (GS) of the dioxygen adducts of the substituted iron tetraphenylporphyrins [FeT(o/p-R)PPO2] were determined at the B3LYP/6-31G(d) level without any symmetry constraints. Binding energy calculations indicated that the presence of electron-withdrawing substituents at the para position favors O2 binding. Calculations of the O-O bond length of the adsorbed dioxygen revealed that the influence of the p-substituent on the activation of dioxygen decreases in the order p-CH3 > p-Cl > p-OCH3 > -H > p-NO2, while the influence of the o-substituent decreases in the order o-NO2 > o-CH3 > o-Cl > o-OCH3 > -H. The low-lying excited states (LLES) of the FeT(o/p-R)PPO2 adducts suggest that the ability to activate dioxygen decreases in the order o-CH3 > o-OCH3 = -H > o-NO2 > o-Cl for o-substituents and p-CH3 > p-Cl > -H > p-NO2 > p-OCH3 for p-substituents. NBO charge population analysis and spin density analysis showed that substitution caused more ß-electrons to be transferred from the iron tetraphenylporphyrin to the dioxygen, which enhanced dioxygen activation. Spin density analysis confirmed that the ß-electron population at the adsorbed dioxygen is an accurate indicator of the degree of dioxygen activation. The trend observed in porphyrin catalytic activity as the substituent on the dioxygen adduct was varied is consistent with the trend in the binding energy. It is clear that substituents at the ortho and para positions in these dioxygen adducts play different roles in dioxygen activation.


Assuntos
Metaloporfirinas/química , Oxigênio/química , Termodinâmica , Elétrons , Modelos Teóricos , Estrutura Molecular
9.
Patient Educ Couns ; 85(3): 336-47, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21316898

RESUMO

OBJECTIVE: In this review, we assess and summarize evidence and gaps in the literature regarding diabetes education in mainland China. METHODS: Using China/Chinese, diabetes and education as key words, articles were obtained from the National Science and Technology Library (NSTL), Chongqing Weipu and Qinghua Tongfang databases. Articles included in this review were further selected based on pre-determined criteria, including studying duration, outcome measurements, and inclusion of control groups. RESULTS: Based on the 34 articles, we found that studies often took place in inpatient and outpatient department. Popular methods used were class teaching, or one-on-one teaching, and knowledge and glycemic control were mostly selected as the outcome measurements. Beneficial effects of diabetes education on knowledge, and glycemic control were demonstrated in studies during a relatively short follow-up (3-6 months). Limitations to the studies selected were that the effects of interventions on behavior change, BMI, blood pressure, lipids, and medical costs were not clearly addressed, and long-term outcomes and adherence to diabetes education was unknown. CONCLUSIONS: Diabetes education had positive impact on glycemic control in mainland China in short duration. PRACTICE IMPLICATIONS: Future studies should use more creative ways of education, and the long-term impact of diabetes education should be evaluated.


Assuntos
Diabetes Mellitus Tipo 2 , Avaliação de Resultados em Cuidados de Saúde , Educação de Pacientes como Assunto/métodos , Autocuidado , China , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/terapia , Hemoglobina A Glicada/metabolismo , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Autocuidado/métodos
10.
Environ Sci Technol ; 44(5): 1786-91, 2010 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-20131791

RESUMO

BiFeO(3) magnetic nanoparticles (BFO MNPs) were prepared with a sol-gel method and characterized as a catalyst. It was found that BFO MNPs effectively catalyzed the decomposition of H(2)O(2) into *OH radicals, being confirmed with electron spin resonance spin-trapping technique and other radical probing techniques. The strong H(2)O(2)-activating ability of BFO MNPs showed promising applications in the oxidative degradation of organic pollutants. When BFO MNPs were used as a heterogeneous Fenton-like catalyst to degrade Rhodamine B, the apparent rate constant for the RhB degradation at 25 degrees C at pH 5.0 in the BFO MNPs-H(2)O(2) system was evaluated to be 2.89 x 10(-2) min(-1), being about 20 folds of that obtained with Fe(3)O(4) MNPs as the catalyst under similar conditions. Moreover, BFO MNPs were demonstrated to have excellent stability and reusability. The catalytic mechanism of BFO MNPs was also investigated with Monte Carlo simulations and density functional theory calculations.


Assuntos
Compostos Orgânicos/isolamento & purificação , Bismuto , Catálise , Óxidos N-Cíclicos/química , Poluentes Ambientais/isolamento & purificação , Compostos Férricos/química , Concentração de Íons de Hidrogênio , Radical Hidroxila/isolamento & purificação , Indicadores e Reagentes , Magnetismo , Microscopia Eletrônica de Varredura , Nanocápsulas/química , Nitratos , Espectrofotometria , Marcadores de Spin , Termodinâmica
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