Evidence for lithium superoxide-like species in the discharge product of a Li–O₂ battery

Yang, Junbing,Zhai, Dengyun,Wang, Hsien-Hau,Lau, Kah Chun,Schlueter, John A.,Du, Peng,Myers, Deborah J.,Sun, Yang-Kook,Curtiss, Larry A.,Amine, Khalil The Royal Society of Chemistry 2013 Physical chemistry chemical physics Vol.15 No.11

<P>We report on the use of a petroleum coke-based activated carbon (AC) with very high surface area for a Li–O<SUB>2</SUB> battery cathode without the use of any additional metal catalysts. Electrochemical measurement in a tetra(ethylene) glycol dimethyl ether–lithium triflate (TEGDME–LiCF<SUB>3</SUB>SO<SUB>3</SUB>) electrolyte results in two voltage plateaus during charging at 3.2–3.5 and 4.2–4.3 V <I>versus</I> Li<SUP>+</SUP>/Li. Herein we present evidence from Raman and magnetic measurements that the lower plateau corresponds to a form of lithium peroxide with superoxide-like properties characterized by a low temperature magnetic phase transition and a high O–O stretching frequency (1125 cm<SUP>−1</SUP>). The magnetic phase transition and the high O–O stretching frequency disappear when charged to above 3.7 V. Theoretical calculations indicate that a surface superoxide structure on lithium peroxide clusters and some lithium peroxide surfaces have an unpaired electron and a high O–O stretching frequency that help explain the observations. These results provide evidence that the form of the lithium peroxide discharge product is important to obtaining a low charge overpotential, and thus improving the round-trip efficiency between discharge and charge.</P> <P>Graphic Abstract</P><P>We report on the use of a petroleum coke-based activated carbon in a Li–O<SUB>2</SUB> battery that gives two voltage plateaus during charging and evidence for a superoxide-like species. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c3cp00069a'> </P>

An Online Synchronous Hybrid BCI System for Multidimensional Control Using MI and SSVEP

Dalin Yang(양다린),Hau Trung Nguyen(누연충하우),Wan-Young Chung(정완영) 대한전자공학회 2017 대한전자공학회 학술대회 Vol.2017 No.6

Recently, Brain Computer Interfaces (BCI) has been used for converting human thoughts to commands for external device. However, a single modality-based control system has some limitations itself such as accuracy and control time. In order to improve system’s performance, this paper presents a hybrid system to implement the multidimensional control using motor imagery (MI) and steady-state visual evoked potentials (SSVEP). MI was employed to control the tank in the game to turn left or right for 90 degrees by imagining the hands grasp motions; whereas SSVEP was employed to control the machine to start, stop, or go forward. Additionally, various classification techniques including Support Vector Machine (SVM) and Artificial Neural Network (ANN) were applied for classifying MI signal. In the other hand, a Canonical Correlation Analysis (CCA) was used for SSVEP frequency recognition. The user was ask to control the car to follow a guiding path. Total error (i.e., total error distances across target points between guiding path and the actual path) was used to evaluate the performance of proposed system. Results shows that the proposed hybrid system can provide a good performance in terms of accuracy and total error along the guiding path. Moreover, the SVM-based classification achieved better accuracy compared with that of ANN-based classification (i.e., 78% vs. 75% on average).

Clinical and Histologic Features of Patients with Biopsy-Proven Metabolic Dysfunction-Associated Fatty Liver Disease

( Shang-chin Huang ),( Hau-jyun Su ),( Jia-horng Kao ),( Tai-chung Tseng ),( Hung-chih Yang ),( Tung-hung Su ),( Pei-jer Chen ),( Chun-jen Liu ) 대한간학회 2021 Gut and Liver Vol.15 No.3

Background/Aims: Fatty liver disease is defined as a cluster of diseases with heterogeneous etiologies, and its definition continues to evolve. The novel conceptional criteria for metabolic dysfunction-associated fatty liver disease (MAFLD) were proposed in 2020 to avoid the exclusion of a certain subpopulation, but their evaluations have been limited. We aimed to examine and compare the clinical as well as histologic features of MAFLD versus nonalcoholic fatty liver disease (NAFLD) in patients with biopsy-proven hepatic steatosis. Methods: From January 2009 to December 2019, 175 patients with histology-proven hepatic steatosis and 10 with cryptogenic cirrhosis who were treated at National Taiwan University Hospital, Taipei, Taiwan, were enrolled. Patients were classified into different groups according to the diagnostic criteria of MAFLD and NAFLD. The clinical and histologic features were then analyzed and compared. Results: In total, 76 patients (41.1%) were diagnosed with both MAFLD and NAFLD, 81 patients (43.8%) were diagnosed with MAFLD alone, nine patients (4.9%) were diagnosed with NAFLD alone, and 19 patients (10.3%) were diagnosed with neither. Those with MAFLD alone exhibited a higher degree of disease severity regarding histology and laboratory data than those with NAFLD alone. Advanced fibrosis was associated with the presences of hepatitis B virus infection and metabolic diseases. Conclusions: The novel diagnostic criteria for MAFLD include an additional 38.9% of patients with hepatic steatosis and can better help identify those with a high degree of disease severity for early intervention than can the previous NAFLD criteria. (Gut Liver 2021;15:451-458)

Increased Stability Toward Oxygen Reduction Products for Lithium-Air Batteries with Oligoether-Functionalized Silane Electrolytes

Zhang, Zhengcheng,Lu, Jun,Assary, Rajeev S.,Du, Peng,Wang, Hsien-Hau,Sun, Yang-Kook,Qin, Yan,Lau, Kah Chun,Greeley, Jeffrey,Redfern, Paul C.,Iddir, Hakim,Curtiss, Larry A.,Amine, Khalil American Chemical Society 2011 JOURNAL OF PHYSICAL CHEMISTRY C - Vol.115 No.51

<P>The successful development of Li-air batteries would significantly increase the possibility of extending the range of electric vehicles. There is much evidence that typical organic carbonate based electrolytes used in lithium ion batteries form lithium carbonates from reaction with oxygen reduction products during discharge in lithium-air cells so more stable electrolytes need to be found. This combined experimental and computational study of an electrolyte based on a tri(ethylene glycol)-substituted trimethylsilane (<ext-link xlink:type='simple'>1NM3</ext-link>) provides evidence that the ethers are more stable toward oxygen reduction discharge species. X-ray photoelectron spectroscopy (XPS) and FTIR experiments show that only lithium oxides and no carbonates are formed when <ext-link xlink:type='simple'>1NM3</ext-link> electrolyte is used. In contrast XPS shows that propylene carbonate (PC) in the same cell configuration decomposes to form lithium carbonates during discharge. Density functional calculations of probable decomposition reaction pathways involving solvated oxygen reduction species confirm that oligoether substituted silanes, as well as other ethers, are more stable to the oxygen reduction products than propylene carbonate. These results indicate that the choice of electrolyte plays a key role in the performance of Li-air batteries.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2011/jpccck.2011.115.issue-51/jp2087412/production/images/medium/jp-2011-087412_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp2087412'>ACS Electronic Supporting Info</A></P>

Optimization of Medium Composition for Improving Biomass Production of Lactobacillus plantarum Pi06 Using the Taguchi Array Design and the Box-Behnken Method

Chin-Fa Hwang,Jen-Han Chang,Jer-Yiing Houng,Cheng-Chih Tsai,Chien-Ku Lin,Hau-Yang Tsen 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.4

An immune-enhancing strain, Lactobacillus plantarum Pi06, isolated from a healthy infant was used for biomass production following optimization of the medium in shake-flask culture. Preliminary studies showed that commercial MRS medium and cultivation under static conditions generated higher biomass production than four other tested media with or without a shaking condition. The selected medium composition, consisting of glucose,yeast extract, soy peptone, ammonium citrate, and corn steep liquor, was further optimized using a systematic method that integrated the Taguchi array design and the Box–Behnken method. The response effects of these factors were first investigated using Taguchi design under an L16 (45) array. The suggested medium composition,derived from Statistica 7.1 using the Taguchi design, was applied to cultivate cells and a biomass of 7.16 g dry cell weight (DCW)/L was obtained. Response surface methodology based on the Box–Behnken method for the three response variables of glucose, yeast extract, and corn steep liquor was then used to further increase the biomass level to 8.94 g DCW/L. The resulting optimum medium consisted of 35 g/L glucose, 35 g/L yeast extract, and 40 mL/L corn steep liquor. Compared with the initial medium, the biomass yield was improved from 4.31 to 8.94 g DCW/L, an enhancement of approximately 107%.