40K is one of the most important atomic species for ultra-cold atomic physics. Due to the extremely low con- centration (0.012%) of 40K in natural abundance of potassium, most experiments use 4-10% enriched potassiu...40K is one of the most important atomic species for ultra-cold atomic physics. Due to the extremely low con- centration (0.012%) of 40K in natural abundance of potassium, most experiments use 4-10% enriched potassium source, which have greatly suffered from the extremely low annual production and significant price hikes in recent years. Using naturally abundant potassium source, we capture 5.4 × 10 6 cold 40K atoms with the help of a high performance of two-dimensional magneto-optical trap (2D+ MOT), which is almost three orders of magnitude greater than previous results without the 2D+ MOT. The number of the 40K atoms is sufficient for most ultra-cold 40K experiments, and our approach provides an ideal alternative for the field.展开更多
Large space circular coal storage dome(LSCCSD)offers an environmental and dependable alternative to open stockpiles,and it has been consequently widely applied in China.However,due to the lack of scientific guidelines...Large space circular coal storage dome(LSCCSD)offers an environmental and dependable alternative to open stockpiles,and it has been consequently widely applied in China.However,due to the lack of scientific guidelines,its natural ventilation performance is lower than expected.Natural ventilation potential strongly depends on the roof geometry and opening mode,which have not yet been investigated for LSCCSD.This paper presents a detailed evaluation of the impact of dome geometry(rise span ratio),opening height,and opening modes on the ventilation performance of LSCCSD.The evaluation is based on computational fluid dynamics(CFD)methods and is validated by available wind tunnel testing.We employed three evaluation indicators,which are wind pressure coefficient,effective ventilation rate,and wind speed ratio.The results demonstrate that the rise span ratio has a significant effect on the wind pressure difference and the effective ventilation rate increases by approximately 9%–42%with a single-annular opening.When double-annular openings are set in a strong positive pressure zone,the effective ventilation rate increases by 100%and the average wind speed ratio increases by 50%.When it is compared with single one with similar opening height,the effective ventilation rate increases by 25%.The optimum natural ventilation performance for LSCCSD is achieved at a rise span ratio of 0.37.In addition,the lateral middle opening is kept higher than the ridge top of the coal pile.The proposed evaluation approach and design parameters provided instructive information in the building design and ventilation control for LSCCSDs.展开更多
Reliable national estimates of CH_4 emissions from natural wetlands depend on model validation based on site observations.We therefore evaluated the performance of the CH_4 MODwetlandmodel in simulating CH_4 emissions...Reliable national estimates of CH_4 emissions from natural wetlands depend on model validation based on site observations.We therefore evaluated the performance of the CH_4 MODwetlandmodel in simulating CH_4 emissions from 11 representative wetland sites in five regions of China.Model performance analysis showed that this method effectively simulates differences in the CH_4 fluxes between different sites and regions.The model efficiency for estimating the daily CH_4 fluxes in the northeastern China(NE),Inner Mongolia and northwestern China(NW),the North China plain and the Middle-Lower Yangtze Plain(E) and the Qinghai Tibetan Plateau(SW) was 0.51,0.20,0.52 and 0.65,respectively.The efficiency for estimating the annual mean CH_4 fluxes in southern China(S) was 0.99.Systematic negative deviation between the simulated and observed CH_4 emissions existed in all regions,especially in the NW region,which had a mean deviation(RMD) value of-36.7%.On the national scale,the root mean square error(RMSE),the RMD,the model efficiency(EF)between the simulated and observed seasonal values were 28.7%,-7.8% and 0.93,respectively.The CH_4 emissions showed the highest sensitivity to air temperature in the NE and SW regions,and to water table depth in the E region.Based on the sensitivity analysis,future climate warming and wetting are likely to increase the wetland CH_4 emissions at different levels in all regions of China.展开更多
Requests and requesting language have been a popular topic for researchers from a wide range of fields including linguistic philosophy,pragmatics,social-pragmatics,and discourse analysis since 1960s.Requesting is a dy...Requests and requesting language have been a popular topic for researchers from a wide range of fields including linguistic philosophy,pragmatics,social-pragmatics,and discourse analysis since 1960s.Requesting is a dynamic process which is the combination of requests and pre-requests,as well as request negotiations.By now,studies mostly focused on the study of how request was initiated and what were the factors lying behind specific choice of one request form over others,and how request-makers pursued their demands when grants were not given as expected.However,limited studies have been published about the development of the strategies children took to avoid predictable refusals.This paper aims to make a contribution to this topic by conducting a longitudinal study lasting for approximately one year with a four-year-old Chinese girl as the subject.By contrasting and comparing the subject’s natural linguistic performance,the author tried to reveal the developmental procedure,and profound cognitive and cultural factors.展开更多
The“six-and-twelve”(6&12)score is a new hepatocellular carcinoma(HCC)prognostic index designed for recommended transarterial chemoembolization(TACE)candidates.Quick and easy to use by the sum of tumor size(cm)an...The“six-and-twelve”(6&12)score is a new hepatocellular carcinoma(HCC)prognostic index designed for recommended transarterial chemoembolization(TACE)candidates.Quick and easy to use by the sum of tumor size(cm)and number,this model identifies three groups with different survival time(the sum is≤6;or>6 but≤12;or>12);a survival benefit with TACE can be expected for HCC patients with a score not exceeding twelve.Recently,Wang ZW et al showed that the“6&12”model was the best system correlated with radiological response after the first TACE.Thus,we wanted to assess its survival prediction ability as well as its prognostic value and compared it to other systems(Barcelona Clinic Liver Cancer,Hong Kong Liver Cancer(HKLC)staging,Albumin-Bilirubin grade,tumor nodularity,infiltrative nature of the tumor,alpha-fetoprotein,Child-Pugh class,and Performance Status score,Cancer of the Liver Italian Program,Model to Estimate Survival for HCC scores,up-to-seven criteria)different from Wang ZW et al study in a multicenter French cohort of HCC including only recommended TACE candidates retrospectively enrolled.As previously demonstrated,we show that the"6&12”score can classify survival within this French cohort,with a prognostic value comparable to that of other systems,except HKLC staging.More importantly,the“6&12”score simplicity and ability in patients’stratification outperform other systems for a routine clinical practice.展开更多
基金Supported by the National Key Research and Development Program of China under Grant Nos 2016YFA0300600 and2016YFA0301500the National Natural Science Foundation of China under Grant Nos 11474347,61227902 and 61775232
文摘40K is one of the most important atomic species for ultra-cold atomic physics. Due to the extremely low con- centration (0.012%) of 40K in natural abundance of potassium, most experiments use 4-10% enriched potassium source, which have greatly suffered from the extremely low annual production and significant price hikes in recent years. Using naturally abundant potassium source, we capture 5.4 × 10 6 cold 40K atoms with the help of a high performance of two-dimensional magneto-optical trap (2D+ MOT), which is almost three orders of magnitude greater than previous results without the 2D+ MOT. The number of the 40K atoms is sufficient for most ultra-cold 40K experiments, and our approach provides an ideal alternative for the field.
文摘Large space circular coal storage dome(LSCCSD)offers an environmental and dependable alternative to open stockpiles,and it has been consequently widely applied in China.However,due to the lack of scientific guidelines,its natural ventilation performance is lower than expected.Natural ventilation potential strongly depends on the roof geometry and opening mode,which have not yet been investigated for LSCCSD.This paper presents a detailed evaluation of the impact of dome geometry(rise span ratio),opening height,and opening modes on the ventilation performance of LSCCSD.The evaluation is based on computational fluid dynamics(CFD)methods and is validated by available wind tunnel testing.We employed three evaluation indicators,which are wind pressure coefficient,effective ventilation rate,and wind speed ratio.The results demonstrate that the rise span ratio has a significant effect on the wind pressure difference and the effective ventilation rate increases by approximately 9%–42%with a single-annular opening.When double-annular openings are set in a strong positive pressure zone,the effective ventilation rate increases by 100%and the average wind speed ratio increases by 50%.When it is compared with single one with similar opening height,the effective ventilation rate increases by 25%.The optimum natural ventilation performance for LSCCSD is achieved at a rise span ratio of 0.37.In addition,the lateral middle opening is kept higher than the ridge top of the coal pile.The proposed evaluation approach and design parameters provided instructive information in the building design and ventilation control for LSCCSDs.
基金supported by the Chinese Academy of Sciences(CAS) strategic pilot technology special funds(No.XDA05020204)the National Natural Science Foundation of China(Nos.31000234,41321064 and 41573069)the Climate Change Special Foundation of China Meteorological Administration(No.CCSF201604)
文摘Reliable national estimates of CH_4 emissions from natural wetlands depend on model validation based on site observations.We therefore evaluated the performance of the CH_4 MODwetlandmodel in simulating CH_4 emissions from 11 representative wetland sites in five regions of China.Model performance analysis showed that this method effectively simulates differences in the CH_4 fluxes between different sites and regions.The model efficiency for estimating the daily CH_4 fluxes in the northeastern China(NE),Inner Mongolia and northwestern China(NW),the North China plain and the Middle-Lower Yangtze Plain(E) and the Qinghai Tibetan Plateau(SW) was 0.51,0.20,0.52 and 0.65,respectively.The efficiency for estimating the annual mean CH_4 fluxes in southern China(S) was 0.99.Systematic negative deviation between the simulated and observed CH_4 emissions existed in all regions,especially in the NW region,which had a mean deviation(RMD) value of-36.7%.On the national scale,the root mean square error(RMSE),the RMD,the model efficiency(EF)between the simulated and observed seasonal values were 28.7%,-7.8% and 0.93,respectively.The CH_4 emissions showed the highest sensitivity to air temperature in the NE and SW regions,and to water table depth in the E region.Based on the sensitivity analysis,future climate warming and wetting are likely to increase the wetland CH_4 emissions at different levels in all regions of China.
文摘Requests and requesting language have been a popular topic for researchers from a wide range of fields including linguistic philosophy,pragmatics,social-pragmatics,and discourse analysis since 1960s.Requesting is a dynamic process which is the combination of requests and pre-requests,as well as request negotiations.By now,studies mostly focused on the study of how request was initiated and what were the factors lying behind specific choice of one request form over others,and how request-makers pursued their demands when grants were not given as expected.However,limited studies have been published about the development of the strategies children took to avoid predictable refusals.This paper aims to make a contribution to this topic by conducting a longitudinal study lasting for approximately one year with a four-year-old Chinese girl as the subject.By contrasting and comparing the subject’s natural linguistic performance,the author tried to reveal the developmental procedure,and profound cognitive and cultural factors.
文摘The“six-and-twelve”(6&12)score is a new hepatocellular carcinoma(HCC)prognostic index designed for recommended transarterial chemoembolization(TACE)candidates.Quick and easy to use by the sum of tumor size(cm)and number,this model identifies three groups with different survival time(the sum is≤6;or>6 but≤12;or>12);a survival benefit with TACE can be expected for HCC patients with a score not exceeding twelve.Recently,Wang ZW et al showed that the“6&12”model was the best system correlated with radiological response after the first TACE.Thus,we wanted to assess its survival prediction ability as well as its prognostic value and compared it to other systems(Barcelona Clinic Liver Cancer,Hong Kong Liver Cancer(HKLC)staging,Albumin-Bilirubin grade,tumor nodularity,infiltrative nature of the tumor,alpha-fetoprotein,Child-Pugh class,and Performance Status score,Cancer of the Liver Italian Program,Model to Estimate Survival for HCC scores,up-to-seven criteria)different from Wang ZW et al study in a multicenter French cohort of HCC including only recommended TACE candidates retrospectively enrolled.As previously demonstrated,we show that the"6&12”score can classify survival within this French cohort,with a prognostic value comparable to that of other systems,except HKLC staging.More importantly,the“6&12”score simplicity and ability in patients’stratification outperform other systems for a routine clinical practice.