Lithium–sulfur(Li–S)batteries are highly regarded as next-generation energy storage devices due to their ultrahigh theoretical energy density of 2600 Wh kg^(−1).However,practical high-energy-density Li–S pouch cell...Lithium–sulfur(Li–S)batteries are highly regarded as next-generation energy storage devices due to their ultrahigh theoretical energy density of 2600 Wh kg^(−1).However,practical high-energy-density Li–S pouch cells suffer from limited cycling lifespan with rapid loss of active materials.Herein,systematic evaluation on a 400 Wh kg^(−1)Li–S pouch cell is carried out to reveal the working and failure mechanism of Li–S batteries under practical conditions.Electrode morphology,spatial distribution and species analysis of sulfur,and capacity retention of electrodes are respectively evaluated after the first cycle of discharge or charge.Considerable lithium polysulfides are found in electrolyte even at the end of discharge or charge,where the sulfur redox reactions are reversible with high capacity retention.Meanwhile,severe morphology change is identified on lithium metal anode,yet there remains substantial active lithium to support the following cycles.This work not only demonstrates unique behaviors of Li–S batteries under practical conditions,which is essential for promoting the progress of Li–S pouch cells,but also affords a systematic evaluation methodology to guide further investigation on high-energy-density Li–S batteries.展开更多
Natural gas output remained stable growth and reached 130.9 billion cubic meters in 2015, 3% higher than the same period last year. Shale gas saw huge progress. China titus became the third country in the world fu!fil...Natural gas output remained stable growth and reached 130.9 billion cubic meters in 2015, 3% higher than the same period last year. Shale gas saw huge progress. China titus became the third country in the world fu!filling commercial development after U.S. attd Canada. Natural gas import growth and growth rate declined obviously, and the imported pipeline gas and LNG totaled 61.2 billion cubic meters in 2015. Apparent natural gas consumption was 186.5 billion cubic meters in 2015, rising by 4.4% as compared with the same period last year, but it hit a historic low. There is higher dozonward pressure on domestic macro economy in 2016. However, natural gas demand will see more rapid growth, propelled by such favorable factors as gas price regulation and environmental protection policies. It is prospected that natural gas market will take a turn for the better than in 2015, and natural gas supply will still be rich in general in 2016.展开更多
In many countries,colorectal cancer is one of the common cancers.It has been confirmed that microsatellite instability(MSI)is one of the most important molecular changes in colorectal cancer.As the recognized precurso...In many countries,colorectal cancer is one of the common cancers.It has been confirmed that microsatellite instability(MSI)is one of the most important molecular changes in colorectal cancer.As the recognized precursor lesions of colorectal cancer,adenomas and some polyps also have MSI phenomenon.This article analyzes the MSI of colorectal cancer and its closely related adenomas and polyps in domestic and foreign literature,and further discusses how to identify colorectal cancer at an early stage and the impact of MSI on the prognosis and treatment of colorectal cancer.展开更多
基金supported by the Beijing Natural Science Foundation(JQ20004)National Natural Science Foundation of China(U1801257)the Scientific and Technological Key Project of Shanxi Province(20191102003)。
文摘Lithium–sulfur(Li–S)batteries are highly regarded as next-generation energy storage devices due to their ultrahigh theoretical energy density of 2600 Wh kg^(−1).However,practical high-energy-density Li–S pouch cells suffer from limited cycling lifespan with rapid loss of active materials.Herein,systematic evaluation on a 400 Wh kg^(−1)Li–S pouch cell is carried out to reveal the working and failure mechanism of Li–S batteries under practical conditions.Electrode morphology,spatial distribution and species analysis of sulfur,and capacity retention of electrodes are respectively evaluated after the first cycle of discharge or charge.Considerable lithium polysulfides are found in electrolyte even at the end of discharge or charge,where the sulfur redox reactions are reversible with high capacity retention.Meanwhile,severe morphology change is identified on lithium metal anode,yet there remains substantial active lithium to support the following cycles.This work not only demonstrates unique behaviors of Li–S batteries under practical conditions,which is essential for promoting the progress of Li–S pouch cells,but also affords a systematic evaluation methodology to guide further investigation on high-energy-density Li–S batteries.
文摘Natural gas output remained stable growth and reached 130.9 billion cubic meters in 2015, 3% higher than the same period last year. Shale gas saw huge progress. China titus became the third country in the world fu!filling commercial development after U.S. attd Canada. Natural gas import growth and growth rate declined obviously, and the imported pipeline gas and LNG totaled 61.2 billion cubic meters in 2015. Apparent natural gas consumption was 186.5 billion cubic meters in 2015, rising by 4.4% as compared with the same period last year, but it hit a historic low. There is higher dozonward pressure on domestic macro economy in 2016. However, natural gas demand will see more rapid growth, propelled by such favorable factors as gas price regulation and environmental protection policies. It is prospected that natural gas market will take a turn for the better than in 2015, and natural gas supply will still be rich in general in 2016.
基金Hebei Province:Beijing Tianjin Hebei basic research cooperation project(2019),Project No.19JCZDJC65800(Z).
文摘In many countries,colorectal cancer is one of the common cancers.It has been confirmed that microsatellite instability(MSI)is one of the most important molecular changes in colorectal cancer.As the recognized precursor lesions of colorectal cancer,adenomas and some polyps also have MSI phenomenon.This article analyzes the MSI of colorectal cancer and its closely related adenomas and polyps in domestic and foreign literature,and further discusses how to identify colorectal cancer at an early stage and the impact of MSI on the prognosis and treatment of colorectal cancer.
