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1.
ACS Appl Mater Interfaces ; 14(9): 11288-11299, 2022 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-35226453

RESUMO

The garnet-type Li7La3Zr2O12 (LLZO) ceramic solid electrolyte combines high Li-ion conductivity at room temperature with high chemical stability. Several all-solid-state Li batteries featuring the LLZO electrolyte and the LiCoO2 (LCO) or LiCoO2-LLZO composite cathode were demonstrated. However, all batteries exhibit rapid capacity fading during cycling, which is often attributed to the formation of cracks due to volume expansion and the contraction of LCO. Excluding the possibility of mechanical failure due to crack formation between the LiCoO2/LLZO interface, a detailed investigation of the LiCoO2/LLZO interface before and after cycling clearly demonstrated cation diffusion between LiCoO2 and the LLZO. This electrochemically driven cation diffusion during cycling causes the formation of an amorphous secondary phase interlayer with high impedance, leading to the observed capacity fading. Furthermore, thermodynamic analysis using density functional theory confirms the possibility of low- or non-conducting secondary phases forming during cycling and offers an additional explanation for the observed capacity fading. Understanding the presented degradation paves the way to increase the cycling stability of garnet-based all-solid-state Li batteries.

2.
ChemSusChem ; 13(16): 3944, 2020 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-32720759

RESUMO

Invited for this month's cover are the groups of Shih-kang Lin at the National Cheng Kung University and Takeshi Abe at Kyoto University. The image shows how interfacial chemistry design can play a role in unlocking higher-energy-density and fast-charging Li4 Ti5 O12 -based lithium-ion batteries for electric vehicle applications. The Full Paper itself is available at 10.1002/cssc.202001086.

3.
ChemSusChem ; 13(16): 4041-4050, 2020 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-32666624

RESUMO

Charge-transfer kinetics between electrodes and electrolytes critically determines the performance of lithium-ion batteries (LIBs). Lithium titanate defect spinel (Li4 Ti5 O12 , LTO) is a safe and durable anode material, but its relatively low energy density limits the range of applications. Utilizing the low potential region of LTO is a straightforward strategy for increasing energy density. However, the electrochemical characteristics of LTO at low potentials and the properties of the solid-electrolyte interphase (SEI) on LTO are not well understood. Here, we investigate the charge-transfer kinetics of the SEI formed between model LTO thin-film electrodes and organic electrolytes with distinct solvation ability using AC impedance spectroscopy whereas their stability was assessed by cyclic voltammetry of ferrocene. With the SEI film on LTO, the Li+ desolvation was rate-determining step but with larger activation energies, which showed a strong dependence on the solvation ability of electrolyte. The activation energies of desolvation for the fluoroethylene carbonate+dimethyl carbonate- and ethylene carbonate+diethyl carbonate-based systems increased from 35 and 55 to 44 and 67 kJ mol-1 , respectively, and that for the propylene carbonate-based system did not noticeably change at around 67 kJ mol-1 . In addition, the SEI passivation of LTO was much slower than that of graphite, and the rate also strongly depended on the solvation ability of the electrolyte. Understanding the surface properties of LTO at low potentials opens the door for high-energy-density LTO-based LIBs.

4.
Opt Lett ; 39(17): 4998-5001, 2014 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-25166058

RESUMO

We demonstrate ultrafast all-optical switching in GaAs microdisk resonators using a femtosecond pump-probe technique through tapered-fiber coupling. The temporal tuning of the resonant modes resulted from the refractive index change due to photoexcited carrier density variation inside the GaAs microdisk resonator. Transmission through the GaAs microdisk resonator can be modulated by more than 10 dB with a switching time window of 8 ps in the switch-off operation using pumping pulses with energies as low as 17.5 pJ. The carrier lifetime was fitted to be 42 ps, much shorter than that of the bulk GaAs, typically of the order of nanoseconds. The above observation indicates that the surface recombination plays an important role in increasing the switching speed.

5.
Bioresour Technol ; 141: 233-9, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23659760

RESUMO

This study applies metabolic flux network analysis (MFA) to evaluate the metabolic flux of fermentative hydrogen production (FHP) with the use of Clostridium tyrobutyricum fed with either glucose or lactate/acetate as substrates. The MFA results suggest that hydraulic retention time (HRT) presents significant impact on hydrogen production from glucose. At HRT between 4 and 18 h, increase of HRT increased hydrogen production but decreased lactate production, while at HRT below 4 h decrease of HRT increased hydrogen production but decreased lactate production. The flux for lactate, butyrate and acetate seemed to affect H2 production, due presumably to their impacts on the balance of NADH, ferredoxin and ATP. It is suggested that the MFA can be a useful tool to provide valuable information for optimization and design of the fermentative hydrogen production process.


Assuntos
Clostridium tyrobutyricum/metabolismo , Hidrogênio/metabolismo , Redes e Vias Metabólicas , Reatores Biológicos , Fermentação , Gerenciamento de Resíduos/métodos
6.
J Card Surg ; 28(2): 159-62, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23350849

RESUMO

Simultaneous mycotic aortic aneurysms are a rare but life-threatening complication. We describe the technique of one stage hybrid open debranching and endovascular repair using three thoracic stent-graft devices deployed to cover the whole aorta to exclude multiple mycotic aneurysms.


Assuntos
Aneurisma Infectado/cirurgia , Aneurisma Aórtico/cirurgia , Implante de Prótese Vascular/métodos , Procedimentos Endovasculares/métodos , Infecções Pneumocócicas/cirurgia , Idoso , Aneurisma Infectado/diagnóstico , Aneurisma Aórtico/diagnóstico , Prótese Vascular , Implante de Prótese Vascular/instrumentação , Procedimentos Endovasculares/instrumentação , Humanos , Masculino , Infecções Pneumocócicas/diagnóstico , Polietilenotereftalatos , Stents
7.
Bioresour Technol ; 102(18): 8378-83, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21511461

RESUMO

This study evaluates the microbial metabolism and energy demand in fermentative biohydrogen production using Clostridium tyrobutyricum FYa102 at different hydraulic retention times (HRT) over a period of 1-18 h. The hydrogen yield shows a positive correlation with the butyrate yield, the B/A ratio, and the Y(H2)/2(Y(HAc)+Y(HBu)) ratio, but a negative correlation with the lactate yield. A decrease in HRT, which is accompanied by an increased biomass growth, tends to decrease the B/A ratio, due presumably to a higher energy demand for microbial growth. The production of lactate at a low HRT, however, may involve an unfavorable change in e(-) equiv distribution to result in a reduced hydrogen production. Finally, the relatively high hydrogen yields observed in the bioreactor with the peptone addition may be ascribed to the utilization of peptone as an additional energy and/or amino-acid source, thus reducing the glucose demand for biomass growth during the hydrogen production process.


Assuntos
Biocombustíveis/análise , Clostridium tyrobutyricum/efeitos dos fármacos , Clostridium tyrobutyricum/metabolismo , Metabolismo Energético/efeitos dos fármacos , Hidrogênio/metabolismo , Peptonas/farmacologia , Acetatos/metabolismo , Trifosfato de Adenosina/biossíntese , Amônia/farmacologia , Reatores Biológicos/microbiologia , Butiratos/metabolismo , Fermentação/efeitos dos fármacos , Glucose/farmacologia , Hidrogenação/efeitos dos fármacos , Lactatos/metabolismo , Fatores de Tempo
8.
Analyst ; 136(6): 1177-82, 2011 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-21267483

RESUMO

We have employed protein A-modified gold nanodots (PA-Au NDs) as a luminescence sensor for the detection of human immunoglobulin G (hIgG) in homogeneous solutions. The luminescent PA-Au NDs were prepared simply by mixing protein A with the luminescent Au NDs (average diameter: ca. 1.8 nm). The specific interactions that occur between protein A and hIgG allowed us to use the PA-Au NDs to detect hIgG selectively. Under optimal conditions [10 nM PA-Au NDs (two protein A molecules per Au ND), 5.0 mM phosphate buffer solution, pH 7.4], the PA-Au ND probe detected hIgG with high sensitivity (limit of detection = 10 nM) and remarkable selectivity (>50-fold) over other proteins. In an assay that took advantage of the competition between protein G and the PA-Au NDs for IgG, we detected protein G at concentrations as low as 85 nM. This PA-Au ND probe allowed determination of the hIgG concentration in plasma samples without any need for sample pretreatment. Our results exhibited a good linear correlation (R(2)=0.97) with those obtained using an enzyme-linked immunosorbent assay. Our simple, sensitive, and selective approach appears to hold practical potential for use in the clinical diagnosis of immune diseases associated with changes in hIgG levels.


Assuntos
Ouro/química , Imunoglobulina G/análise , Medições Luminescentes/métodos , Nanopartículas Metálicas/química , Plasma/metabolismo , Proteína Estafilocócica A/química , Tampões (Química) , Ensaio de Imunoadsorção Enzimática , Humanos , Concentração de Íons de Hidrogênio , Imunoglobulina G/sangue , Luminescência , Fosfatos/química , Plasma/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
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