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1.
Int J Med Inform ; 177: 105137, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37419041

RESUMO

BACKGROUND: The Electronic Health Record Sharing System (eHRSS) is an electronic platform for two-way communication between the public and private sectors in Hong Kong. The authorised healthcare professionals (HCProfs) could access and upload patients' health records on the eHR Viewer in the eHRSS. This study aims to evaluate the usage of eHR viewer among the HCProfs from the private sector by 1) examining the correlation of various factors and the data access of eHR viewer; 2) investigating the trend on data access and upload to eHR viewer by time period and domain. METHODS: A total of 3972 HCProfs from private hospitals, group practice, and solo practice were included in the study. Regression analysis was performed to identify the correlation between various factors and the data access to eHR viewer. Trends on accessing and data uploading to eHR viewer by time period and domains were evaluated. Trends on data uploading to eHR viewer by time period and domains were presented in the line chart as well. FINDINGS: All types of HCProfs had a higher likelihood of accessing the eHR viewer as compared to those from private hospitals. HCProfs with specialities (apart from anaesthesia) had a higher possibility of accessing the eHR viewer than general practitioners without specialities. HCProfs participating in the Public-Private Partnership (PPP) Programme and the eHealth System (Subsidies) (eHS(S)) were more likely to access the eHR viewer. The overall trend of accessing eHR viewer was rising notably from 2016 to 2022, every domain showed rising trends, especially the laboratory domain with a 5-times increase between 2016 and 2022. CONCLUSION: HCProfs with speciality were more likely to access the eHR viewer (except anaesthesiology), compared with the general practitioners. Participation in the PPP programmes and eHS(S) also increased the access rate of the eHR viewer. Besides, the use of eHR viewer (accessing and data uploading) would be influenced by social policy and the epidemic. Future research should focus on the impact of government programmes on eHRSS adoption.


Assuntos
Registros Eletrônicos de Saúde , Clínicos Gerais , Humanos , Comunicação , Software , Atenção à Saúde
2.
Front Bioeng Biotechnol ; 9: 636571, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34738007

RESUMO

Background: Asymmetrical foot posture and properties alterations of the gastrocnemius muscle (GM) and Achilles tendon (AT) were observed in knee osteoarthritis (KOA). We aimed to investigate the inter-limbs asymmetries in foot posture and the properties of GM and AT and explore the association between them. Methods: A total of 62 subjects with unilateral or bilateral KOA were included in this study: 30 patients with unilateral pain and 32 patients with bilateral pain were assigned to the bilateral group (BG) and unilateral group (UG), respectively. The relatively serious leg (RSL) and relatively moderate leg (RML) were judged according to the severity of symptoms assessed by using visual analogue scale (VAS) motion. Foot posture and asymmetrical foot posture scores were assessed based on Foot Posture index (FPI-6). Subsequently, all the participants received an assessment for properties of GM and AT, including tone/tension (Hz), stiffness (N/m), and elasticity. We calculated the asymmetry index of AT (Asy -AT) in both legs and the difference of muscle properties between medial and lateral gastrocnemius (D-MLG) in the ipsilateral limb. Results: Asymmetry of foot posture was categorized into three types including normal, asymmetry, and severe asymmetry. The percentage of subjects classified as normal was higher in the BG (62.5%) than in the UG (36.67%), p < 0.05. Tension of AT and tone of lateral gastrocnemius (LG) in RSL were higher than those in RML (15.71 ± 0.91 vs. 15.23 ± 1.01; 25.31 ± 2.09 vs. 23.96 ± 2.08, p < 0.01 and p < 0.01, respectively), and stiffness of AT in the RSL was higher than that in RML (676.58 ± 111.45 vs. 625.66 ± 111.19, p < 0.01). Meanwhile, a positive relationship was found between ipsilateral FPI and tone of MG and LG in the left leg (0.246 per degree, 95% CI: -0.001, 0.129; p = 0.054 and 0.293 per degree, 95% CI: -0.014, 0.157; p = 0.021, respectively) and right leg (0.363 per degree, 95% CI: 0.033, 0.146; p = 0.004 and 0.272 per degree, 95% CI: 0.007, -0.144; p = 0.032, respectively). Moreover, a positive link was observed between asymmetrical FPI scores and K/L grade (0.291 per degree, 95% CI: 0.018, 0.216; p = 0.022). Furthermore, a significantly greater Asy-AT(tension) was detected in the UG than that in the BG (UG vs. UG: 8.20 ± 5.09% vs. 5.11 ± 4.72%, p < 0.01). Additionally, an increased asymmetrical FPI score (i.e., more severe asymmetry) was significantly associated with increases in Asy-AT(tension) and Asy-AT(stiffness) (0.42 per degree, 95% CI: 0.533, 1.881; p = 0.001 and 0.369 per degree, 95% CI: 0.596, 2.82; p = 0.003, respectively). Conclusions: The stiffness and tension of AT and the tone of LG in RSL were higher than those in RML in KOA patients, and inter-limbs foot posture and tension of AT were more asymmetrical in unilateral KOA patients compared to patients with bilateral KOA. Notably, foot posture, as an important biomechanical factor, was significantly associated with properties of GM, AT, and K/L grade in KOA patients.

3.
Front Med (Lausanne) ; 8: 699921, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34778281

RESUMO

Background: There is increased interest in proprioceptive training for knee osteoarthritis (KOA). However, little consensus supports the effectiveness of this intervention. Objective: This meta-analysis aimed to assess the effects of proprioceptive training on symptoms, function, and proprioception in people with KOA. Methods: The PubMed, Cochrane Library, Web of Science, and EMBASE databases were systematically searched from the inception dates to April 16, 2021 for relevant randomized controlled trials (RCTs). Data were pooled by calculating the standardized mean differences (SMDs) and 95% confidence intervals (CIs). A random-effects model was used for the analyses. Results: A total of 24 RCTs involving 1,275 participants were included in our analysis. This study indicated that compared to no intervention, proprioceptive training significantly improved pain, stiffness, physical function, joint position sense (JPS), muscle strength, mobility, and knee ROM (P < 0.05) in people with KOA. When compared to other non-proprioceptive training, proprioceptive training provided better results in terms of JPS (SMD = -1.28, 95%CI: [-1.64, -0.92], I 2 = 0%, P < 0.00001) and mobility (timed walk over spongy surface) (SMD = -0.76, 95%CI: [-1.33, -0.18], I 2 = 64%, P = 0.01), and other results are similar. When proprioceptive training plus other non-proprioceptive training compared to other non-proprioceptive training, the two groups showed similar outcomes, but there was a greater improvement for JPS (SMD = -1.54, 95%CI: [-2.74, -0.34], I 2 = 79%, P = 0.01), physical function (SMD = -0.34, 95%CI: [-0.56, -0.12], I 2 = 0%, P = 0.003), and knee ROM (P < 0.05) in the proprioceptive training plus other non-proprioceptive training group. When proprioceptive training plus conventional physiotherapy compared against conventional physiotherapy, the two groups demonstrated similar outcomes, but there was a significant improvement for JPS (SMD = -0.95, 95%CI: [-1.73, -0.18], I 2 = 78%, P = 0.02) in the proprioceptive training plus conventional physiotherapy group. Conclusions: Proprioceptive training is safe and effective in treating KOA. There is some evidence that proprioceptive training combined with general non-proprioceptive training or conventional physiotherapy appears to be more effective and should be considered as part of the rehabilitation program. However, given that the majority of current studies investigated the short-term effect of these proprioceptive training programs, more large-scale and well-designed studies with long-term follow up are needed to determine the long-term effects of these proprioceptive training regimes in KOA. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/#recordDetails, PROSPERO, identifier: CRD42021240587.

4.
Front Physiol ; 12: 641968, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34135767

RESUMO

Objective: The benefits of Pilates for blood glucose and lipids remain unclear. The purpose of this study was to examine the effect of Pilates on their levels. Methods: Searches were conducted in five databases to identify relevant articles published until October 29, 2020. Paired reviewers independently screened the articles and extracted data from each included study. Meta-analysis was performed to assess the effects of Pilates on blood glucose and lipids. Subgroup analyses and sensitivity analyses were conducted to explore heterogeneity. Results: According to the inclusion and exclusion criteria, 15 randomized controlled trials (RCTs) comprising 587 participants were included in the study. Overall, the Pilates group (PG) had a significantly greater reduction in post-prandial blood glucose than the control group (CG) (MD = -22.25 mg/dL, 95% CI: [-28.34, 16.17] mg/dL, P < 0.00001, I2 = 0%); glycated hemoglobin (HbA1c) (MD = -0.78%, 95% CI: [-1.13, -0.42]%, P < 0.0001, I2 = 88%); total cholesterol (TC) (MD = -20.90 mg/dL, 95% CI: [-37.21, -4.60] mg/dL, P = 0.01, I2 = 84%); triglycerides (TG) (MD = -12.59 mg/dL, 95% CI: [-19.88, -5.29] mg/dL, P = 0.0007, I2 = 86%); and low density lipoprotein cholesterol (LDL-C) (MD = -12.39 mg/dL, 95% CI: [-16.82, -7.95] mg/dL, P < 0.00001, I2 = 45%) compared to CG, whereas no significant difference was detected between the two groups in fasting blood glucose (MD = -7.04 mg/dL, 95% CI: [-17.26, 3.17] mg/dL, P = 0.18, I2 = 93%), insulin (MD = -1.44 µU/mL, 95% CI: [-4.30, 1.41] µU/mL, P = 0.32, I2 = 0%); and high density lipoprotein cholesterol (HDL-C) (MD = -2.68 mg/dL, 95% CI: [-9.03, 3.67] mg/dL, P = 0.41, I2 = 89%). However, by subgroup analysis, we found that compared to the CG, PG showed no significant improvement in blood glucose and lipids levels for non-diabetics, while it presented a significantly greater decrease in post-prandial blood glucose, TC, TG, and LDL-C for diabetic patients. Notably, for diabetic patients, Pilates and medication treatments showed no significant reduction in fasting blood glucose (MD = -7.00 mg/dL, 95% CI: [-26.06, 12.06] mg/dL, P = 0.40) and HbA1c (MD = -0.23%, 95% CI: [-0.58, 0.13]%, P = 0.21, I2 = 0%) than medications treatment used alone, and Pilates combined with medications and dietary treatments presented no significant improvement in fasting blood glucose than a combination of medications and dietary treatments (MD = -10.90 mg/dL, 95% CI: [-32.35, 10.54] mg/dL, P = 0.32, I2 = 94%). Conclusions: Overall, Pilates could improve post-prandial blood glucose, fasting blood glucose, HbA1c, TG, TC, and LDL-C for diabetic patients, which could be influenced by its duration and intensity. Moreover, it had no significant effect on blood glucose and lipids for non-diabetic individuals. However, Pilates, as an adjunctive treatment to medications was not superior to medications used alone in lowering fasting blood glucose and HbA1c. Furthermore, Pilates combined with medications and dietary treatments showed no significant improvement in fasting blood glucose, whereas it had a greater reduction in post-prandial blood glucose and HbA1c for diabetic patients. Systematic Review Registration: https://osf.io/xgv6w.

5.
Medicine (Baltimore) ; 100(4): e23891, 2021 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-33530184

RESUMO

BACKGROUND: Electroacupuncture is increasingly used in rehabilitation for postoperative cognitive dysfunction (POCD), but relevant evidence remains unclear for patients receiving total knee arthroplasty (TKA). METHODS: The databases research of PubMed, EMBASE, CINAHL, and China National Knowledge Infrastructure (CNKI) will be conducted from inception to December 31, 2020. The relevant randomized controlled trials (RCTs) from data will be screened one by one. The remaining studies that meet the inclusion criteria will be extracted and analyzed using RevMan V.5.3 software. Paired 2 reviewers will assess quality of the included studies and publication bias by using the Cochrane Collaboration risk of bias tool, and Egger test and Begg test respectively. And grading of recommendations assessment, development and evaluation (GRADE) will be used to estimate the quality of evidence. RESULTS: In this study, we will analyze the effect of electroacupuncture on Mini-Mental State Examination (MMSE), interleukin 1ß (IL-1ß), tumor necrosis factor-α (TNF-α), S100-ß protein, and adverse events for patients with TKA. CONCLUSION: Our findings will provide evidence for the effectiveness of electroacupuncture on the treatment and prevention of POCD for TKA patients. REGISTRATION NUMBER: Available at: https://osf.io/azyt9 (DOI number: 10.17605/OSF.IO/AZYT9).


Assuntos
Artroplastia do Joelho/efeitos adversos , Eletroacupuntura , Metanálise como Assunto , Complicações Cognitivas Pós-Operatórias/terapia , Revisões Sistemáticas como Assunto , Protocolos Clínicos , Humanos , Complicações Cognitivas Pós-Operatórias/prevenção & controle , Ensaios Clínicos Controlados Aleatórios como Assunto , Projetos de Pesquisa
6.
Medicine (Baltimore) ; 99(24): e20659, 2020 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-32541508

RESUMO

BACKGROUND: Knee osteoarthritis (KOA) is a common progressive joint disorder in old people. Bushen huoxue (BSHX) is a classical method of TCM in treating KOA. However, there is no systematic review related to BSHX for KOA. The purpose of this study is to provide a comprehensive and reliable evaluation of the clinical evidence of BSHX in the treatment of KOA. METHODS: We searched relevant studies on BSHX for KOA from the databases of PubMed, Embase, MEDLINE, Cochrane Library Central Register of Controlled Trials, China national knowledge infrastructure database (CNKI), Wan fang database, Chongqing VIP information, and SinoMed from their inception to May 2020. Two researchers will select and evaluate qualified studies independently. The primary outcomes of this review will focus on pain intensity. The meta-analyses will be performed by using the RevMan 5.3. RESULTS: The study will provide a comprehensive evaluation of the efficacy and safety of the BSHX method for patients with KOA. CONCLUSION: The results of this systematic review will provide evidence to judge whether BSHX is an effective intervention for patients with KOA.


Assuntos
Artralgia/tratamento farmacológico , Artralgia/etiologia , Medicamentos de Ervas Chinesas/uso terapêutico , Metanálise como Assunto , Osteoartrite do Joelho/complicações , Fitoterapia , Projetos de Pesquisa , Revisões Sistemáticas como Assunto , Humanos
7.
Medicine (Baltimore) ; 99(24): e20697, 2020 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-32541521

RESUMO

BACKGROUND: Primary osteoporosis (POP) is one of the most common orthopedic diseases with a high risk of fracture. Effective treatment of POP is of great significance to reduce the rate of disability and improve the quality of life. Bushen qianggu (BSQG) is a classical method of TCM in treating POP. However, there is no systematic review related to BSQG for POP. The purpose of this study is to provide a comprehensive and reliable evaluation of the clinical evidence of BSQG in the treatment of POP. METHODS AND ANALYSIS: Relevant randomized controlled trial literature evaluating the effect of BSQG on patients with POP will be obtained by searching the PubMed, Embase, MEDLINE, Cochrane Library Central Register of Controlled Trials, China national knowledge infrastructure database, Wan fang database, Chongqing VIP information, and SinoMed from their inception to May 2020. Two researchers will select and evaluate qualified studies independently. The bone mineral density value and the incidence of fractures will be accepted as the primary outcomes. The meta-analyses will be performed by using the RevMan 5.3. RESULTS: This study will provide a comprehensive evaluation of the efficacy and safety of BSQG method for patients with POP. CONCLUSION: The conclusion of our systematic review will provide evidence to judge whether BSQG is an effective intervention for patients with POP. TRIAL REGISTRATION NUMBER: 10.17605/OSF.IO/ZMX3W.


Assuntos
Medicamentos de Ervas Chinesas/uso terapêutico , Metanálise como Assunto , Osteoporose/tratamento farmacológico , Fitoterapia , Projetos de Pesquisa , Revisões Sistemáticas como Assunto , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto , Resultado do Tratamento
8.
Nat Mater ; 19(9): 992-998, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32451511

RESUMO

Radiation-induced segregation is well known in metals, but has been rarely studied in ceramics. We discover that radiation can induce notable segregation of one of the constituent elements to grain boundaries in a ceramic, despite the fact that the ceramic forms a line compound and therefore has a strong thermodynamic driving force to resist off-stoichiometry. Specifically, irradiation of silicon carbide at 300 °C leads to carbon enrichment near grain boundaries, whereas the enrichment diminishes for irradiation at 600 °C. The temperature dependence of this radiation-induced segregation is different from that shown in metallic systems. Using an ab initio informed rate theory model, we demonstrate that this difference is introduced by the unique defect energy landscapes present in the covalent system. Additionally, we discover that grain boundaries in unirradiated silicon carbide grown by chemical vapour deposition are intrinsically carbon-depleted. The inherent grain boundary chemistry and its evolution under radiation are both critical for understanding the many properties of ceramics associated with grain boundaries.

9.
ACS Appl Mater Interfaces ; 12(18): 20859-20866, 2020 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-32282183

RESUMO

The growth of single crystals of Ge-rich SiGe alloys in an extended composition range is demonstrated using the nanomembrane (NM) platform and III-V growth substrates. Thin films of high-Ge-content SiGe films are grown on GaAs(001) to below the kinetic critical thickness and released from the growth substrate by selectively etching a release layer to relax the strain. The resulting crystalline nanomembranes at the natural lattice constant of the alloy are transferred to a new host and epitaxially overgrown at similar compositions to make a thicker single crystal. Straightforward critical-thickness calculations demonstrate that a very wide range of group IV alloys, including those involving Sn, can be fabricated using the NM platform and the proper choice of III-V substrate. Motivations for making new group IV alloys center on band gap engineering for the development of novel group IV optoelectronic structures and devices.

10.
Biomed Res Int ; 2020: 7649157, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32149135

RESUMO

There is limited research on the changes of biomechanical characteristics of the lumbar extensor myofascia in elderly patients with chronic low back pain. This study aimed to compare the biomechanical properties of the lumbar extensor myofascia in elderly patients with chronic low back pain and healthy people when resting and to analyze the relationship between the Japanese Orthopedic Association (JOA) score, visual analog scale (VAS) score, Cobb angle, and disease course and the biomechanical characteristics of the lumbar extensor myofascia. This case-control study included 40 elderly patients with chronic low back pain and 40 healthy volunteers. MyotonPRO was used to measure the biomechanical properties of the bilateral lumbar extensor myofascia (at L3/L4 level) in all participants, and the reliability of the MyotonPRO test was measured. Cobb angle was measured from lumbar computed tomography or magnetic resonance imaging data. JOA and VAS scores were used to evaluate lumbar function and pain. We found that muscle tone, stiffness, and elasticity of the left and right lumbar extensor myofascia in patients with chronic low back pain were very reliable among different operators. The average lumbar extensor muscle tone and stiffness were significantly higher in patients with chronic low back pain than those in healthy controls. The average elasticity of the lumbar extensor myofascia of patients with chronic low back pain was significantly lower than that of the healthy controls. The JOA score was negatively correlated, while the VAS score was positively correlated with the mean values of tone, stiffness, and elasticity of the bilateral lumbar extensor myofascia (logarithmic decrement). Disease course had no significant correlation with muscle tone, stiffness, and elasticity of the lumbar extensor myofascia. No significant correlation was found between Cobb angle and muscle tone, stiffness, and elasticity of the lumbar extensor myofascia in either group.


Assuntos
Fenômenos Biomecânicos , Dor Lombar/fisiopatologia , Vértebras Lombares/fisiopatologia , Região Lombossacral/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Eletromiografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/fisiopatologia , Reprodutibilidade dos Testes
11.
PLoS One ; 14(7): e0220521, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31365582

RESUMO

The reliability of MyotonPRO that can monitor the mechanical properties of tissues is still unclear. This study aimed to analyze the within-day inter-operator and between-day intra-operator reliability of MyotonPRO for assessing tone and stiffness of quadriceps femoris and patellar tendon at different knee angles. The tone and stiffness of healthy participants (15 males and 15 females, aged 24.7±1.6 years) in the supine and resting position were measured using the MyotonPRO device. The measurements were quantified at 0°, 30°, 60°, and 90° of knee flexion. The intraclass correlation coefficient (ICC), standard error of measurement (SEM), and minimal detectable change (MDC) were calculated and a Bland-Altman analysis was conducted to estimate reliability. The results indicated excellent inter-operator reliability (ICC > 0.78) and good to excellent intra-operator reliability (ICC > 0.41). The inter-operator SEM measurements ranged between 0.1-0.9 Hz and 3.8-37.9 N/m, and intra-operator SEM ranged between 0.5-1.3 Hz and 7.9-52.0 N/m. The inter-operator MDC ranged between 0.3-2.5 Hz and 10.5-105.1 N/m, and intra-operator SEM ranged between 1.1-3.3 Hz and 21.9-144.1 N/m. The agreement of inter-operator was better than that of intra-operator. The study concluded that MyotonPRO is a reliable device to detect the tone and stiffness of quadriceps femoris and patellar tendon.


Assuntos
Algoritmos , Técnicas de Imagem por Elasticidade/instrumentação , Articulação do Joelho/fisiologia , Tono Muscular/fisiologia , Ligamento Patelar/fisiologia , Músculo Quadríceps/fisiologia , Amplitude de Movimento Articular/fisiologia , Adulto , Fenômenos Biomecânicos , Feminino , Humanos , Masculino , Variações Dependentes do Observador , Reprodutibilidade dos Testes , Adulto Jovem
12.
ACS Appl Mater Interfaces ; 9(46): 41034-41042, 2017 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-29094920

RESUMO

Integration of emerging complex-oxide compounds into sophisticated nanoscale single-crystal geometries faces significant challenges arising from the kinetics of vapor-phase thin-film epitaxial growth. A comparison of the crystallization of the model perovskite SrTiO3 (STO) on (001) STO and oxidized (001) Si substrates indicates that there is a viable alternative route that can yield three-dimensional epitaxial synthesis, an approach in which STO is crystallized from an amorphous thin film by postdeposition annealing. The crystallization of amorphous STO on single-crystal (001) STO substrates occurs via solid-phase epitaxy (SPE), without nucleation and with a temperature-dependent amorphous/crystalline interface velocity. In comparison, the crystallization of STO on SiO2/(001) Si substrates requires nucleation, resulting in a polycrystalline film with crystal sizes on the order of 10 nm. A comparison of the temperature dependence of the nucleation and growth processes for these two substrates indicates that it will be possible to create crystalline STO materials using low-temperature crystallization from a crystalline seed, even in the presence of interfaces with other materials. These processes provide a potential route for the formation of single crystals with intricate three-dimensional nanoscale geometries.

13.
Nanotechnology ; 28(21): 215704, 2017 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-28471752

RESUMO

The effects of a 45 min anneal at 800 °C on the physical properties and microstructure of a five-period GaAs1-x Bi x /GaAs1-y Bi y superlattice with y ≠ x were studied using room-temperature photoluminesence spectroscopy, high-resolution x-ray diffraction, high-angle annular-dark-field scanning transmission electron microscopy (HAADF-STEM), and atom probe tomography (APT). The anneal resulted in a substantial increase of the photoluminesence intensity over that observed in the as-deposited sample, indicating annihilation of non-radiative recombination centers and stability of the superlattice structure during the anneal. However, some precipitation of Bi from the GaAs1-x Bi x also occurred. The characteristics of phase separation that occurred within these precipitates were investigated in detail by APT and HAADF-STEM. They indicate that the precipitation reaction involves formation of embedded nano-scale liquid droplets that can accelerate local Bi dissolution from the GaAs1-x Bi x matrix by moving through it. Preservation of nanometer scale sharp Bi concentration gradients in the growth direction suggested that very little solid state diffusion of Bi occurred during the anneal. The observed gradient in precipitate number density with distance from the sample surface further supports hypotheses of an enabling role of Ga vacancies in the precipitation process.

14.
ACS Appl Mater Interfaces ; 8(16): 10572-80, 2016 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-27035035

RESUMO

Metal oxide coatings can improve the electrochemical stability of cathodes and hence, their cycle-life in rechargeable batteries. However, such coatings often impose an additional electrical and ionic transport resistance to cathode surfaces leading to poor charge-discharge capacity at high C-rates. Here, a mixed oxide (Al2O3)1-x(Ga2O3)x alloy coating, prepared via atomic layer deposition (ALD), on Li[Ni0.5Mn0.3Co0.2]O2 (NMC) cathodes is developed that has increased electron conductivity and demonstrated an improved rate performance in comparison to uncoated NMC. A "co-pulsing" ALD technique was used which allows intimate and controlled ternary mixing of deposited film to obtain nanometer-thick mixed oxide coatings. Co-pulsing allows for independent control over film composition and thickness in contrast to separate sequential pulsing of the metal sources. (Al2O3)1-x(Ga2O3)x alloy coatings were demonstrated to improve the cycle life of the battery. Cycle tests show that increasing Al-content in alloy coatings increases capacity retention; whereas a mixture of compositions near (Al2O3)0.5(Ga2O3)0.5 was found to produce the optimal rate performance.

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