According to a statistic,approximately 6 trillion cigarettes are smoked each year all over the world,which produces approximately 1.2 million tons of discarded cigarette butts.The discarded cigarette filters are non-b...According to a statistic,approximately 6 trillion cigarettes are smoked each year all over the world,which produces approximately 1.2 million tons of discarded cigarette butts.The discarded cigarette filters are non-biodegradable,thus they produce a mass of waste disposal and cause environmental pollution is-sue.For the purpose of transforming waste into wealth and reducing environmental pollution,nitrogen and sulfur co-doped carbon nanofiber/carbon black(N,S-CNF/CB)composite derived from the discarded cigarette filters is employed to modify glass fiber(GF)separator for the first time in this study.N,S-CNF improves binding ability towards sodium polysulfides(SPSs)by chemisorption.Non-polar CB limits the dissolution of SPSs in the liquid electrolyte by physisorption.The experiment and density functional theory calculation results indicate that a RT-Na/S battery with a N,S-CNF/CB+GF separator exhibits good cycling stability and rate performance.After 100 cycles at a low current rate of 0.1 C,a RT-Na/S battery with a sulfur mass fraction of 71%delivers a discharge capacity of 703 mAh g^(−1).In addition,at a high current rate of 0.5 C,a discharge capacity of 527 mAh g^(−1) is still maintained after 900 cycles with a very low capacity fading rate of 0.035%per cycle.展开更多
The NO oxidation processes on CrO_2(110) was investigated by virtue of DFT + U calculation together with microkinetic analysis, aiming to uncover the reaction mechanism and activity-limiting factors for CrO_2 catalyst...The NO oxidation processes on CrO_2(110) was investigated by virtue of DFT + U calculation together with microkinetic analysis, aiming to uncover the reaction mechanism and activity-limiting factors for CrO_2 catalyst. It was found that NO oxidation on CrO_2(110) has to be triggered with the lattice Obri involved(Mars-van Krevelen mechanism) rather than the Langmuir-Hinshelwood path occurring at the Cr_(5 c) sites alone. Specifically, the optimal reaction path was identified. Quantitatively, the microkinetic analysis showed that CrO_2(110) can exhibit a high turnover rate of 0.978 s^(-1) for NO oxidation at room temperature.Such an activity could originate from the bifunctional synergetic catalytic mechanism, in which the Cr_(5c)sites can exclusively adsorb NO and the Obri is very reactive and provides oxidative species. However, it is worth noting that, as the reactive Obri tightly binds NO_2, the nitrate species was found to be difficult removed and constituted the key poisoning species, eventually limiting the overall activity of CrO_2. This work demonstrated the considerable catalytic ability of CrO_2 for NO oxidation at room temperature, and the understanding may facilitate the further design of more active Cr-based catalyst.展开更多
Background: Our hypothesis was that only established and persistent injuries and complications after positioning in the Trendelenburg position are reported and detected, despite that patients may have great discomfort...Background: Our hypothesis was that only established and persistent injuries and complications after positioning in the Trendelenburg position are reported and detected, despite that patients may have great discomfort after surgery. Aim: The aim of this study was to explore patient reported discomfort, pain and functional decrease two hours, 24 hours and four weeks after laparoscopic resection of the colon in the prone lithotomy position, as well as factors potentially associated with reported pain. Methods: A longitudinal self-report questionnaire study was conducted at three time-points. Results: A total of 37 patients responded. Findings show that patients mostly reported pain in relation to the surgical area, but also related to other areas that may be linked to positioning. Conclusion: Even though patients reported mild pain, several of the patients still reported this, four weeks postoperatively, as well as some functional decrease. Our findings support the need to focus on preventing positioning injuries.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51631004 and 52130101)the Basic Construction Fund in Jilin Province Budget for 2019(No.2019C042-8).
文摘According to a statistic,approximately 6 trillion cigarettes are smoked each year all over the world,which produces approximately 1.2 million tons of discarded cigarette butts.The discarded cigarette filters are non-biodegradable,thus they produce a mass of waste disposal and cause environmental pollution is-sue.For the purpose of transforming waste into wealth and reducing environmental pollution,nitrogen and sulfur co-doped carbon nanofiber/carbon black(N,S-CNF/CB)composite derived from the discarded cigarette filters is employed to modify glass fiber(GF)separator for the first time in this study.N,S-CNF improves binding ability towards sodium polysulfides(SPSs)by chemisorption.Non-polar CB limits the dissolution of SPSs in the liquid electrolyte by physisorption.The experiment and density functional theory calculation results indicate that a RT-Na/S battery with a N,S-CNF/CB+GF separator exhibits good cycling stability and rate performance.After 100 cycles at a low current rate of 0.1 C,a RT-Na/S battery with a sulfur mass fraction of 71%delivers a discharge capacity of 703 mAh g^(−1).In addition,at a high current rate of 0.5 C,a discharge capacity of 527 mAh g^(−1) is still maintained after 900 cycles with a very low capacity fading rate of 0.035%per cycle.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.21333003,21622305)National Ten Thousand Talent Program for Young Top-notch Talents in ChinaThe Shanghai Shuguang Scholar Program(No.17SG30)
文摘The NO oxidation processes on CrO_2(110) was investigated by virtue of DFT + U calculation together with microkinetic analysis, aiming to uncover the reaction mechanism and activity-limiting factors for CrO_2 catalyst. It was found that NO oxidation on CrO_2(110) has to be triggered with the lattice Obri involved(Mars-van Krevelen mechanism) rather than the Langmuir-Hinshelwood path occurring at the Cr_(5 c) sites alone. Specifically, the optimal reaction path was identified. Quantitatively, the microkinetic analysis showed that CrO_2(110) can exhibit a high turnover rate of 0.978 s^(-1) for NO oxidation at room temperature.Such an activity could originate from the bifunctional synergetic catalytic mechanism, in which the Cr_(5c)sites can exclusively adsorb NO and the Obri is very reactive and provides oxidative species. However, it is worth noting that, as the reactive Obri tightly binds NO_2, the nitrate species was found to be difficult removed and constituted the key poisoning species, eventually limiting the overall activity of CrO_2. This work demonstrated the considerable catalytic ability of CrO_2 for NO oxidation at room temperature, and the understanding may facilitate the further design of more active Cr-based catalyst.
文摘Background: Our hypothesis was that only established and persistent injuries and complications after positioning in the Trendelenburg position are reported and detected, despite that patients may have great discomfort after surgery. Aim: The aim of this study was to explore patient reported discomfort, pain and functional decrease two hours, 24 hours and four weeks after laparoscopic resection of the colon in the prone lithotomy position, as well as factors potentially associated with reported pain. Methods: A longitudinal self-report questionnaire study was conducted at three time-points. Results: A total of 37 patients responded. Findings show that patients mostly reported pain in relation to the surgical area, but also related to other areas that may be linked to positioning. Conclusion: Even though patients reported mild pain, several of the patients still reported this, four weeks postoperatively, as well as some functional decrease. Our findings support the need to focus on preventing positioning injuries.
