Thermal behavior, microstructure, phase transformation, and crystal growth kinetics of nano-scale Fe3+-doped TiO2 xerogel powders

Miao Shui,Yue Song,Qingchun Wang,Yuanlong Ren 한국물리학회 2010 Current Applied Physics Vol.10 No.5

Titania based ceramics are promising materials for environmental sensors, high efficiency photocatalyst. Ion doping is an effective method to improve the properties by modifying their microstructure and phase composition. In this study, TiO2 particles doped with Fe3+ were prepared by sol-gel method using Ferric nitrate and tetrabutyl titanate as precursors. Fe3+ was incorporated in the TiO2 matrix during thermal treatment in different temperatures. Thermal analysis, TEM and X-ray diffraction were used to characterize the TiO2 powder. Microstructure, phase content, and cell parameters were calculated according to Rietveld refinement software GSAS. The interaction mechanism of Fe3+ in crystal lattice of titanium dioxide and the crystal growth kinetics of Fe3+-doped TiO2 are discussed.

Synthesis and electrochemical performance of Li1þxV3O8 as cathode material prepared by citric acid and tartaric acid assisted solegel processes

Miao Shui,Weidong Zheng,Jie Shu,Qingchun Wang,Shan Gao,Dan Xu,Liangliang Cheng,Lin Feng,Yuanlong Ren 한국물리학회 2013 Current Applied Physics Vol.13 No.3

Lithium-ion battery cathode material Li1þxV3O8 is synthesized by a citric acid/tartaric acid assisted sol egel method and sintered at 350 C, 450 C and 550 C for 3 h for the formation of Li1þxV3O8 phase. The synthesized samples were fully characterized by FTIR, TG/DTA, XRD, SEM, EIS and chargeedischarge tests. Li1þxV3O8 material synthesized by tartaric acid assisted route and sintered at 450 C for 3 h shows best electro-chemical performance. It shows a high initial capacity of 249 mAh g1 and still reserves a discharge capacity of 260 mAh g1 after 50 cycles. Moreover, in the case of tartaric assisted products, no capacity decadence is observed in 50 cycles. XRD together with TG/DTA measurements reveal that compared with citric acid assisted products, the adoption of tartaric acid as chelating agent effectively lowers the crystallization temperature of amorphous Li1þxV3O8. Therefore, precursors obtained by tartaric acid route calcinated at 450 C for 3 h exhibit lower crystallinity and smaller grain size, which contributes to the better electrochemical performance of the cathode electrodes. From EIS measurements, the bulk resistance is reduced, which favors the intercalation and de-intercalation of lithium ions while cycling.

Time-domain simulations of transient response in LiFePO4 cathode lithium ion batteries

Xiaoping Xu,Miao Shui,Weidong Zheng,Jie Shu,Lei Hui,Linxia Xu,Liangliang Cheng,Lin Feng,Yuanlong Ren 한국물리학회 2014 Current Applied Physics Vol.14 No.5

The time domain transients of batteries comprised of LiFePO4 cathode material exhibit large nonlinearity with the increasing discharging rates. Hence, the calculated overpotential transients match the experimental determined well only when the discharging current is low enough. The results of electrochemical impedance spectra at different OCV level indicate that the change of the parameters of equivalent circuit or even the circuit architecture are probably responsible for the large discrepancy between the predicted and the measured transient profiles. By taking the change of equivalent circuit model at high discharging current into consideration, we successfully simulate the time domain transients of polarization within the entire discharging current range. Also with the help of circuit analysis, the contribution of the ohmic resistance, charge transfer impedance and solid-state diffusion impedance to total polarization has been differentiated as a function of discharging time.

Comparative studies on potential dependent electrochemical impedance spectroscopy of cathode material 0.5Li2MnO3$0.5LiNi0.5Mn0.5O2 for the initial two charging cycles

Chao Chen,Shu Chen,Miao Shui,Xiaoping Xu,Weidong Zheng,Lin Feng,Jie Shu,Yuanlong Ren 한국물리학회 2015 Current Applied Physics Vol.15 No.2

Cathode material 0.5Li2MnO3·0.5LiNi0.5Mn0.5O2 is successfully synthesized by citrate acid assisted sol -gel method and shows pretty good electro-chemical performance. To elucidate the electro-chemical reactions and charge carrier transportation kinetics in the charge-discharge process, series of electrochemical impedance spectra for the first and the second charge process are measured on multiple given state of charges. The rapid augmentation of resistance to electronic conduction and ionic conduction within the voltage range 4.45-4.6 V where the removal of Li2O from Li2MnO3 component takes place gives us more evidence about the complicated “structurally integrated” feature of this material. The relatively large span of the arc responsible for electronic conduction and the extremely large Mn3+ related charge transfer resistance at the beginning of the second charging indicate that after one complete charge-discharge cycle, Li2MnO3 and LiNi0.5Mn0.5O2 domains still reserve its original structure and will keep its structure for the followed cycles.

Expression of DNA Damage Response Proteins and Associations with Clinicopathologic Characteristics in Chinese Familial Breast Cancer Patients with BRCA1/2 Mutations

Xinyi Zhu,Tian Tian,Miao Ruan,Jia Rao,Wentao Yang,Xu Cai,Menghong Sun,Guangqi Qin,Zhonghua Zhao,Jiong Wu,Zhimin Shao,Ruohong Shui,Zhen Hu 한국유방암학회 2018 Journal of breast cancer Vol.21 No.3

Purpose: The characteristic expression of DNA damage response proteins in familial breast cancers with BRCA1, BRCA2, or non-BRCA1/2 mutations has not been analyzed in Chinese patients. Our study aimed to assess the differential expression of microcephalin 1 (BRIT1), ATM serine/threonine kinase (ATM), checkpoint kinase 2 (CHEK2), BRCA1, RAD51 recombinase (RAD51), and poly (ADP-ribose) polymerase 1 (PARP-1) and establish the profile of Chinese familial breast cancers with different mutation status. Methods: We constructed five tissue microarrays from 183 familial breast cancer patients (31 with BRCA1 mutations; 14 with BRCA2 mutations, and 138 with non-BRCA1/2 mutations). The DNA response and repair markers used for immunohistochemistry analysis included BRIT1, ATM, CHEK2, BRCA1, RAD51, and PARP-1. The expressions of these proteins were analyzed in BRCA1/2 mutated tumors. The association between pathologic characteristics with BRCA1/2 mutation status was also analyzed. Results: In familial breast cancer patients, BRCA1 mutated tumors were more frequent with high nuclear grade, estrogen receptor/progesterone receptor/human epidermal growth factor receptor 2 negative, low Ki-67, and positive CK5/6. BRCA1 mutated tumors had lower CHEK2 and higher cytoplasmic BRIT1 expression than BRCA2 and non-BRCA1/2 mutation tumors. BRCA2-associated tumors showed higher CHEK2 and cytoplasmic RAD51 expression than those in other groups. Nuclear PARP-1 expression in BRCA1/2-associated tumors was significantly higher than in non-BRCA1/2 mutation tumors. Moreover, we found quite a few of negative PARP-1 expression cases in BRCA1/2 mutated groups. Conclusion: The clinicopathologic findings of BRCA1-associated Chinese familial breast cancers were similar to the results of other studies. Chinese familial breast cancer patients with BRCA1/2 mutations might have distinctive expression of different DNA damage response proteins. The reduced expression of PARP-1 in Chinese BRCA1/2 mutated breast cancer patients could influence the therapeutic outcome of PARP-1 inhibitors.

The preparation, performance and lithiation mechanism of cobalt-doped zinc oxide as a high performance anode material for LIB

Yue Li,WanWan Li,Minhua Fang,XiaoLin Yao,Chao Chen,Miao Shui,Jie Shu,Yuanlong Ren 한국물리학회 2017 Current Applied Physics Vol.17 No.8

Zn1-xCoxO (0 x 0.15) anode material was prepared by an easy polyacrylamide assisted sol-gel route. The successful replacement of Zinc by Cobalt within Cobalt content x 0.09 was confirmed by structural characterization. The introduction of Cobalt element greatly improved the electro-chemical performances of the matrix Zinc oxide. Without carbon coating, at the 20th cycle, Zn0.91Co0.09O anode still preserved a capacity a little bit more than 1000 mA h g1 and a capacity more than 600 mA h g1 was retained at the end of the 50th cycle. Better rate capability was also witnessed. The SEM, EIS at OCV, CV and in situ XRD were further carried out to elucidate the lithiation mechanism. The role Cobalt doping played can be summarized as follows: the stabilization of the Li2Zn phase, the minimization of charge transfer resistance and the enhanced reversibility of the reduction from metal oxide to metal.