Lithium-sulphur(Li-S)batteries are currently considered as next-generation battery technology.Sulphur is an attractive positive electrode for lithium metal batteries,mainly due to its high capacity(1675 m Ah g^(-1))an...Lithium-sulphur(Li-S)batteries are currently considered as next-generation battery technology.Sulphur is an attractive positive electrode for lithium metal batteries,mainly due to its high capacity(1675 m Ah g^(-1))and high specific energy(2600 Wh kg^(-1)).The electrochemical reaction of lithium with sulphur in non-aqueous electrolytes results in the formation of electrolyte soluble intermediate lithium-polysulphides.The dissolved polysulphides shuttle to the anode and get reduced at the anode resulting in Li metal corrosion.The solubility of polysulphide gradually reduces the amount of sulphur in the cathode,thereby limiting the cycle life of Li-S batteries.Several strategies have been proposed to improve the cycling stability of Li-S batteries.A unique approach to eliminate the polysulphide shuttle is to use ultramicroporous carbon(UMC)as a host for sulphur.The pore size of UMC which is below 7A,is the bottleneck for carbonate solvents to access sulphur/polysulphides confined in the pores,thereby preventing the polysulphide dissolution.This perspective article will emphasise the role of UMC host in directing the lithiation mechanism of sulphur and in inhibiting polysulphide dissolution,including the resulting parasitic reaction on the lithium anode.Further,the challenges that need to be addressed by UMC-S based Li-S batteries,and the strategies to realise high power density,high Coulombic efficiency,and resilient Li-S batteries will be discussed.展开更多
This paper explores some design parameters of an interior permanent magnet synchronous motor that contribute to enhancing motor performance.Various geometry parameters such as magnet dimension,machine diameter,stator ...This paper explores some design parameters of an interior permanent magnet synchronous motor that contribute to enhancing motor performance.Various geometry parameters such as magnet dimension,machine diameter,stator teeth height,and number of poles are analyzed to compare overall torque,power,and torque ripples in order to select the best design parameters and their ranges.Pyleecan,an open-source software,is used to design and optimize the motor for electric vehicle applications.Following optimization with Non-dominated Sorting Genetic Algorithm(NSGA-Ⅱ),two designs A and B were obtained for two objective functions and the corresponding torque ripples values of the design A and B were later reduced by 32%and 77%.Additionally,the impact of different magnet grades on the output performances is analyzed.展开更多
Background: The US FDA has recently approved autologous cultured fibroblast cells (ACF) as treatment for cutaneous contour defects. ACF provides an alternative to synthetic fillers or fat grafting with the significant...Background: The US FDA has recently approved autologous cultured fibroblast cells (ACF) as treatment for cutaneous contour defects. ACF provides an alternative to synthetic fillers or fat grafting with the significant advantage of producing longer lasting effect. Methods: This was a prospective open label single group clinical study to demonstrate the clinical efficacy of ACF that we have replicated in our lab. The study enrolled 18 patients with nasolabial folds from 2 centres in Malaysia in 2011-2012. ACF at dose of 23 or 92 million cells were injected on 3 occasions at 4 weeks interval. Efficacy at 6- and 12-month post treatment was assessed using a standardized 7-point scale which was performed by the 2 investigators as well as a panel of 7 independent evaluators. Results: We obtained a successful outcome (primary endpoint), defined as improvement in the appearance of the nasolabial fold of at least 2 points on the 7-point scale, in 33% of patients as assessed by investigators at 12-month follow-up and in 22% of patients assessed by independent evaluators. Investigators also found 78% of patients having had a 1-point improvement from baseline while independent evaluators found 83% of patients having improved by as much. Patients were uniformly (100%) satisfied with the improvement in their appearance. No treatment-related adverse event was reported. Baseline score and follow-up duration had significant effect on treatment response. The greater the baseline severity and the longer the post-treatment follow-up, the better the response to ACF. Larger dose of cells (92 million cells) has little additional effect suggesting that the 1 mL dose (23 million cells) is near optimal. Older patients showed a trend towards poorer response but this was not statistically significant. Conclusions: We have successfully replicated the laboratory method and clinical procedure to perform ACF treatment which was effective in improving the appearance of nasolabial folds in some patients.展开更多
When using the image mutual information to assess the quality of reconstructed image in pseudothermal light ghost imaging, a negative exponential behavior with respect to the measurement number is observed. Based on i...When using the image mutual information to assess the quality of reconstructed image in pseudothermal light ghost imaging, a negative exponential behavior with respect to the measurement number is observed. Based on information theory and a few simple and verifiable assumptions, semi-quantitative model of image mutual information under varying measurement numbers is established. It is the Gaussian characteristics of the bucket detector output probability distribution that leads to this negative exponential behavior. Designed experiments verify the model.展开更多
基金partly funded by the German Research Foundation(DFG)under Project ID 390874152(POLiS Cluster of Excellence,EXC2154)。
文摘Lithium-sulphur(Li-S)batteries are currently considered as next-generation battery technology.Sulphur is an attractive positive electrode for lithium metal batteries,mainly due to its high capacity(1675 m Ah g^(-1))and high specific energy(2600 Wh kg^(-1)).The electrochemical reaction of lithium with sulphur in non-aqueous electrolytes results in the formation of electrolyte soluble intermediate lithium-polysulphides.The dissolved polysulphides shuttle to the anode and get reduced at the anode resulting in Li metal corrosion.The solubility of polysulphide gradually reduces the amount of sulphur in the cathode,thereby limiting the cycle life of Li-S batteries.Several strategies have been proposed to improve the cycling stability of Li-S batteries.A unique approach to eliminate the polysulphide shuttle is to use ultramicroporous carbon(UMC)as a host for sulphur.The pore size of UMC which is below 7A,is the bottleneck for carbonate solvents to access sulphur/polysulphides confined in the pores,thereby preventing the polysulphide dissolution.This perspective article will emphasise the role of UMC host in directing the lithiation mechanism of sulphur and in inhibiting polysulphide dissolution,including the resulting parasitic reaction on the lithium anode.Further,the challenges that need to be addressed by UMC-S based Li-S batteries,and the strategies to realise high power density,high Coulombic efficiency,and resilient Li-S batteries will be discussed.
基金funded by the Advanced Sustainable Manufacturing Technologies(ASTUTE2020)operation supporting manufacturing companies across Wales,which has been part-funded by the European Regional Development Fund through the Welsh Government and the participating Higher Education Institutions。
文摘This paper explores some design parameters of an interior permanent magnet synchronous motor that contribute to enhancing motor performance.Various geometry parameters such as magnet dimension,machine diameter,stator teeth height,and number of poles are analyzed to compare overall torque,power,and torque ripples in order to select the best design parameters and their ranges.Pyleecan,an open-source software,is used to design and optimize the motor for electric vehicle applications.Following optimization with Non-dominated Sorting Genetic Algorithm(NSGA-Ⅱ),two designs A and B were obtained for two objective functions and the corresponding torque ripples values of the design A and B were later reduced by 32%and 77%.Additionally,the impact of different magnet grades on the output performances is analyzed.
文摘Background: The US FDA has recently approved autologous cultured fibroblast cells (ACF) as treatment for cutaneous contour defects. ACF provides an alternative to synthetic fillers or fat grafting with the significant advantage of producing longer lasting effect. Methods: This was a prospective open label single group clinical study to demonstrate the clinical efficacy of ACF that we have replicated in our lab. The study enrolled 18 patients with nasolabial folds from 2 centres in Malaysia in 2011-2012. ACF at dose of 23 or 92 million cells were injected on 3 occasions at 4 weeks interval. Efficacy at 6- and 12-month post treatment was assessed using a standardized 7-point scale which was performed by the 2 investigators as well as a panel of 7 independent evaluators. Results: We obtained a successful outcome (primary endpoint), defined as improvement in the appearance of the nasolabial fold of at least 2 points on the 7-point scale, in 33% of patients as assessed by investigators at 12-month follow-up and in 22% of patients assessed by independent evaluators. Investigators also found 78% of patients having had a 1-point improvement from baseline while independent evaluators found 83% of patients having improved by as much. Patients were uniformly (100%) satisfied with the improvement in their appearance. No treatment-related adverse event was reported. Baseline score and follow-up duration had significant effect on treatment response. The greater the baseline severity and the longer the post-treatment follow-up, the better the response to ACF. Larger dose of cells (92 million cells) has little additional effect suggesting that the 1 mL dose (23 million cells) is near optimal. Older patients showed a trend towards poorer response but this was not statistically significant. Conclusions: We have successfully replicated the laboratory method and clinical procedure to perform ACF treatment which was effective in improving the appearance of nasolabial folds in some patients.
基金supported by the National Natural Science Foundation of China (61631014, 61401036, 61471051 and 61531003)the National Science Fund for Distinguished Young Scholars of China (61225003)+1 种基金the China Postdoctoral Science Foundation (2015M580008)the Youth Research and Innovation Program of BUPT (2015RC12)
文摘When using the image mutual information to assess the quality of reconstructed image in pseudothermal light ghost imaging, a negative exponential behavior with respect to the measurement number is observed. Based on information theory and a few simple and verifiable assumptions, semi-quantitative model of image mutual information under varying measurement numbers is established. It is the Gaussian characteristics of the bucket detector output probability distribution that leads to this negative exponential behavior. Designed experiments verify the model.
