We investigate the electronic structures and phase stability of ZnO, CdO and the related alloys in rocksalt（B1）and wurzite（B4） crystal, using the first-principle density functional theory within the hybrid functio...We investigate the electronic structures and phase stability of ZnO, CdO and the related alloys in rocksalt（B1）and wurzite（B4） crystal, using the first-principle density functional theory within the hybrid functional approximation. By varying the concentration of Zn components from 0% to 100%, we find that the Zn_xCd（1-x）O alloy undergoes a phase transition from octahedron to tetrahedron at x = 0.32, in agreement with the recent experimental findings. The phase transition leads to a mutation of the electron mobility originated from the changes of the effective mass. Our results qualify Zn O/Cd O alloy as an attractive candidate for photo-electrochemical and solar cell power applications.展开更多
A method of the fuzzy cross-correlation factor exponent in dynamics is researched and proposed to diagnose abnormality of cracks in the concrete dam. Moreover, the Logistic time series changing from period-doubling bi...A method of the fuzzy cross-correlation factor exponent in dynamics is researched and proposed to diagnose abnormality of cracks in the concrete dam. Moreover, the Logistic time series changing from period-doubling bifurcation to chaos is tested first using this method. Results indicate that it can distinguish inherent dynamics of time series and can detect mutations. Considering that cracks in the concrete dam constitute an open, dissipative and complex nonlinear dynamical system, a typical crack on the downstream face of a concrete gravity arch dam is analyzed with the proposed method. Two distinct mutations are discovered to indicate that the abnormality diagnosis of cracks in the concrete dam is achieved dynamically through this method. Furthermore, because it can be directly utilized in the measured crack opening displacement series to complete abnormality diagnosis, it has a good prospect for practical applications.展开更多
Developing electrochemical energy storage and conversion devices(e.g.,water splitting,regenerative fuel cells and rechargeable metal-air batteries)driven by intermittent renewable energy sources holds a great potentia...Developing electrochemical energy storage and conversion devices(e.g.,water splitting,regenerative fuel cells and rechargeable metal-air batteries)driven by intermittent renewable energy sources holds a great potential to facilitate global energy transition and alleviate the associated environmental issues.However,the involved kinetically sluggish oxygen evolution reaction(OER)severely limits the entire reaction efficiency,thus designing high-performance materials toward efficient OER is of prime significance to remove this obstacle.Among various materials,cost-effective perovskite oxides have drawn particular attention due to their desirable catalytic activity,excellent stability and large reserves.To date,substantial efforts have been dedicated with varying degrees of success to promoting OER on perovskite oxides,which have generated multiple reviews from various perspectives,e.g.,electronic structure modulation and heteroatom doping and various applications.Nonetheless,the reviews that comprehensively and systematically focus on the latest intellectual design strategies of perovskite oxides toward efficient OER are quite limited.To bridge the gap,this review thus emphatically concentrates on this very topic with broader coverages,more comparative discussions and deeper insights into the synthetic modulation,doping,surface engineering,structure mutation and hybrids.More specifically,this review elucidates,in details,the underlying causality between the being-tuned physiochemical properties[e.g.,electronic structure,metal-oxygen(M-O)bonding configuration,adsorption capacity of oxygenated species and electrical conductivity]of the intellectually designed perovskite oxides and the resulting OER performances,coupled with perspectives and potential challenges on future research.It is our sincere hope for this review to provide the scientific community with more insights for developing advanced perovskite oxides with high OER catalytic efficiency and further stimulate more exciting applications.展开更多
To study the resistance mechanism of clinical isolates of Ureaplasma urealyticum resistant to fluoroquinolones Methods Thirteen isolates of Ureaplasma urealyticum resistant to six fluoroquinolones were selected out ...To study the resistance mechanism of clinical isolates of Ureaplasma urealyticum resistant to fluoroquinolones Methods Thirteen isolates of Ureaplasma urealyticum resistant to six fluoroquinolones were selected out of 184 clinical isolates and their QRDRs (quinolone resistance determining region) gyrA, gyrB, parC and parE were amplified by PCR Sequencing results were compared to those susceptible reference strains and a comparison of deduced amino acid sequences were performed Results Sequence comparison revealed a C to A change at 87nt of gyrA QRDR leading to the substitution of Asp95 with glutamic acid and a C to T change at 50nt of parC QRDR leading to the substitution of Ser80 with leucine Conclusion These results suggest that a C to A change at 87nt of gyrA QRDR and a C to T change at 50nt of parC QRDR are associated with fluoroquinolone resistance of Ureaplasma urealyticum展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11474273 and 11634003the Youth Innovation Promotion Association of Chinese Academy of Sciences under Grant No 2017154
文摘We investigate the electronic structures and phase stability of ZnO, CdO and the related alloys in rocksalt（B1）and wurzite（B4） crystal, using the first-principle density functional theory within the hybrid functional approximation. By varying the concentration of Zn components from 0% to 100%, we find that the Zn_xCd（1-x）O alloy undergoes a phase transition from octahedron to tetrahedron at x = 0.32, in agreement with the recent experimental findings. The phase transition leads to a mutation of the electron mobility originated from the changes of the effective mass. Our results qualify Zn O/Cd O alloy as an attractive candidate for photo-electrochemical and solar cell power applications.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51079046, 50909041, 50809025, 50879024)the National Science and Technology Support Plan (Grant Nos. 2008BAB29B03, 2008BAB29B06)+7 种基金the Special Fund of State Key Laboratory of China (Grant Nos. 2009586012, 2010585212)the Fundamental Research Funds for the Central Universities (Grant Nos. 2009B08514, 2010B20414, 2010B14114)China Hydropower Engineering Consulting Group Co. Science and Technology Support Project (Grant No. CHC-KJ-2007-02)Jiangsu Province "333 High-Level Personnel Training Project" (Grant No. 2017-B08037)the Natural Science Foundation of Hohai University (Grant No. 2008426811)Graduate Innovation Program of Universities in Jiangsu Province (Grant No. CX09B_163Z)the Science Foundation for The Excellent Youth Scholars of Ministry of Education of China (Grant No. 20070294023)Dominant Discipline Construction Program Funded Projects of Universities in Jiangsu Province
文摘A method of the fuzzy cross-correlation factor exponent in dynamics is researched and proposed to diagnose abnormality of cracks in the concrete dam. Moreover, the Logistic time series changing from period-doubling bifurcation to chaos is tested first using this method. Results indicate that it can distinguish inherent dynamics of time series and can detect mutations. Considering that cracks in the concrete dam constitute an open, dissipative and complex nonlinear dynamical system, a typical crack on the downstream face of a concrete gravity arch dam is analyzed with the proposed method. Two distinct mutations are discovered to indicate that the abnormality diagnosis of cracks in the concrete dam is achieved dynamically through this method. Furthermore, because it can be directly utilized in the measured crack opening displacement series to complete abnormality diagnosis, it has a good prospect for practical applications.
基金supported by the National Natural Science Foundation of China(NSFC,Grant No.22109182)the Natural Science Foundation of Hunan Province,China(2022JJ30684)+1 种基金the Start-up Funding of Central South University(No.206030104)the Natural Sciences and Engineering Research Council(NSERC)of Canada Discovery Grant(GRPIN−2016−05494).
文摘Developing electrochemical energy storage and conversion devices(e.g.,water splitting,regenerative fuel cells and rechargeable metal-air batteries)driven by intermittent renewable energy sources holds a great potential to facilitate global energy transition and alleviate the associated environmental issues.However,the involved kinetically sluggish oxygen evolution reaction(OER)severely limits the entire reaction efficiency,thus designing high-performance materials toward efficient OER is of prime significance to remove this obstacle.Among various materials,cost-effective perovskite oxides have drawn particular attention due to their desirable catalytic activity,excellent stability and large reserves.To date,substantial efforts have been dedicated with varying degrees of success to promoting OER on perovskite oxides,which have generated multiple reviews from various perspectives,e.g.,electronic structure modulation and heteroatom doping and various applications.Nonetheless,the reviews that comprehensively and systematically focus on the latest intellectual design strategies of perovskite oxides toward efficient OER are quite limited.To bridge the gap,this review thus emphatically concentrates on this very topic with broader coverages,more comparative discussions and deeper insights into the synthetic modulation,doping,surface engineering,structure mutation and hybrids.More specifically,this review elucidates,in details,the underlying causality between the being-tuned physiochemical properties[e.g.,electronic structure,metal-oxygen(M-O)bonding configuration,adsorption capacity of oxygenated species and electrical conductivity]of the intellectually designed perovskite oxides and the resulting OER performances,coupled with perspectives and potential challenges on future research.It is our sincere hope for this review to provide the scientific community with more insights for developing advanced perovskite oxides with high OER catalytic efficiency and further stimulate more exciting applications.
基金ThisstudywassupportedbyagrantfromtheEducationCommitteeofHunanProvince (No 0 0A0 0 9)
文摘To study the resistance mechanism of clinical isolates of Ureaplasma urealyticum resistant to fluoroquinolones Methods Thirteen isolates of Ureaplasma urealyticum resistant to six fluoroquinolones were selected out of 184 clinical isolates and their QRDRs (quinolone resistance determining region) gyrA, gyrB, parC and parE were amplified by PCR Sequencing results were compared to those susceptible reference strains and a comparison of deduced amino acid sequences were performed Results Sequence comparison revealed a C to A change at 87nt of gyrA QRDR leading to the substitution of Asp95 with glutamic acid and a C to T change at 50nt of parC QRDR leading to the substitution of Ser80 with leucine Conclusion These results suggest that a C to A change at 87nt of gyrA QRDR and a C to T change at 50nt of parC QRDR are associated with fluoroquinolone resistance of Ureaplasma urealyticum
