针对煤炭地下气化(UCG)技术制备的合成气具有温度高(>200℃)、压力大(3.35 MPa)、饱和含水量大及组分复杂(含CH_(4)、H_(2)、CO_(2)和CO等)的特点,设计并采用膜分离+溶剂吸收耦合的处理方法以实现地下煤合成气中CO_(2)的脱除和H_(2)...针对煤炭地下气化(UCG)技术制备的合成气具有温度高(>200℃)、压力大(3.35 MPa)、饱和含水量大及组分复杂(含CH_(4)、H_(2)、CO_(2)和CO等)的特点,设计并采用膜分离+溶剂吸收耦合的处理方法以实现地下煤合成气中CO_(2)的脱除和H_(2)的提纯。地下煤合成气经过二级膜分离单元的处理,实现了CO_(2)/H_(2)与CH_(4)的分离并得到了脱碳净化气,其中CO_(2)含量(物质的量分数)≤3%,该膜分离工艺所需能耗为0.297 k W·h/m^(3)。使用醇胺吸收法处理CO_(2)/H_(2)混合气,并通过配方溶液筛选、工艺流程优化和校验分析等方法开展了研究,最终得到了H_(2)纯度(物质的量分数)≥99%的产品,该醇胺吸收法的能耗为0.341 k W·h/m^(3)。使用膜分离+溶剂吸收耦合处理复杂工况的地下煤合成气,可得到脱碳净化气、纯CO_(2)和工业级H_(2),提高了项目的经济价值,具有较大的应用潜力。展开更多
The response of the global subduction rate to global warming was assessed based on a set of Intergovernmental Panel on Climate Change （IPCC） Fourth Assessment Report （AR4） models. It was found that the subduction ...The response of the global subduction rate to global warming was assessed based on a set of Intergovernmental Panel on Climate Change （IPCC） Fourth Assessment Report （AR4） models. It was found that the subduction rate of the global ocean could be significantly reduced under a warming climate, as compared to a simulation of the present-day climate. The reduction in the subduction volume was quantitatively estimated at about 40 Sv and was found to be= primarily induced by the decreasing of the lateral induction term due to a shallower winter mixed layer depth. The shrinking of the winter mixed layer would result from intensified stratification caused by increased heat input into the ocean under a warming climate. A reduction in subduction associated with the vertical pumping term was estimated at about 5 Sv. F^rther, in the Southern Ocean, a significant reduction in subduction was estimated at around 24 Sv, indicating a substantial contribution to the weakening of global subduction.展开更多
Needs in scintimammography applications,especially for small animal cardiac imaging,lead to develop a small field of view,high spatial resolution gamma camera with a pinhole collimator.However the ideal pinhole collim...Needs in scintimammography applications,especially for small animal cardiac imaging,lead to develop a small field of view,high spatial resolution gamma camera with a pinhole collimator.However the ideal pinhole collimator must keep a compromise between spatial resolution and sensitivity.In order to design a pinhole collimator with an optimized sensitivity and spatial resolution,the spatial resolution and the geometric sensitivity response as a function of the source to collimator distance has been obtained by means of Monte-Carlo simulation for a small field of view gamma camera with a pinhole collimator of various-hole diameters.The results show that the camera with pinhole of 1 mm,1.5 mm and 2 mm diameter has respectively spatial resolution of 1.5 mm,2.25 mm and 3 mm and geometric sensitivity of 0.016%,0.022%and 0.036%,while the source to collimator distance is 3 cm.We chose the pinhole collimator with hole diameter size of 1.2 mm for our the gamma camera designed based on the trade-off between sensitivity and resolution.展开更多
A compact gamma-ray detector with good spatial resolution for emission computed tomography (E-CT) applications has been developed. The detector is composed of NaI(Tl) scintillation pixels array and Hamamastu R2486-05 ...A compact gamma-ray detector with good spatial resolution for emission computed tomography (E-CT) applications has been developed. The detector is composed of NaI(Tl) scintillation pixels array and Hamamastu R2486-05 PSPMT. Having a pixel size of 2 mm × 2 mm and an overall dimension of 48.2 mm × 48.2mm × 5 mm, it has 484 pixels in a 22×22 matrix. An average spatial resolution of 2.5mm (FWHM) was achieved. The slope of position linearity is constant within 10% in a range of 40mm. After corrections, the average value of differential non-linearity and absolute non-linearity were 0.16mm and 0.535mm respectively, and a 17% at FWHM of total energy resolution for 241Am was obtained.展开更多
At present,it is believed that the freezing point temperature of seawater is a function of salinity and pressure,and the freezing point is a key parameter in a coupled air-sea-ice system.Generally,empirical formulas o...At present,it is believed that the freezing point temperature of seawater is a function of salinity and pressure,and the freezing point is a key parameter in a coupled air-sea-ice system.Generally,empirical formulas or methods are used to calculate the freezing point of seawater.Especially in high-pressure situations,e.g.,under a thick ice sheet or ice shelf,the pressure term must be taken into account in the determination of seawater freezing point temperature.This study summarized various methods that have been used to calculate seawater freezing point with high pressure.The methods that were employed in two ocean-ice models were also assessed.We identified the disadvantages of these methods used in these two models and addressed the corresponding uncertainties of the freezing point temperature formulas.This study provides useful information on the calculation of the freezing point temperature in numerical modeling and indicates a need to investigate the sensitivity of numerical simulations to the uncertainties in the freezing point temperature in future.展开更多
文摘针对煤炭地下气化(UCG)技术制备的合成气具有温度高(>200℃)、压力大(3.35 MPa)、饱和含水量大及组分复杂(含CH_(4)、H_(2)、CO_(2)和CO等)的特点,设计并采用膜分离+溶剂吸收耦合的处理方法以实现地下煤合成气中CO_(2)的脱除和H_(2)的提纯。地下煤合成气经过二级膜分离单元的处理,实现了CO_(2)/H_(2)与CH_(4)的分离并得到了脱碳净化气,其中CO_(2)含量(物质的量分数)≤3%,该膜分离工艺所需能耗为0.297 k W·h/m^(3)。使用醇胺吸收法处理CO_(2)/H_(2)混合气,并通过配方溶液筛选、工艺流程优化和校验分析等方法开展了研究,最终得到了H_(2)纯度(物质的量分数)≥99%的产品,该醇胺吸收法的能耗为0.341 k W·h/m^(3)。使用膜分离+溶剂吸收耦合处理复杂工况的地下煤合成气,可得到脱碳净化气、纯CO_(2)和工业级H_(2),提高了项目的经济价值,具有较大的应用潜力。
基金supported by the Chinese National Key Basic Research Program(2010CB950301)National Natural Science Foundation of China(NSFC)(Grant No.41276200)+3 种基金the Special Program for China Meteorology Trade(Grant No.GYHY201306020)the Scientific Research Foundation for the Introduction of Talent of Nanjing University of Information Science and Technology(S8112066001)General University Science Research Project of Jiangsu Province(13KJB170019)funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘The response of the global subduction rate to global warming was assessed based on a set of Intergovernmental Panel on Climate Change （IPCC） Fourth Assessment Report （AR4） models. It was found that the subduction rate of the global ocean could be significantly reduced under a warming climate, as compared to a simulation of the present-day climate. The reduction in the subduction volume was quantitatively estimated at about 40 Sv and was found to be= primarily induced by the decreasing of the lateral induction term due to a shallower winter mixed layer depth. The shrinking of the winter mixed layer would result from intensified stratification caused by increased heat input into the ocean under a warming climate. A reduction in subduction associated with the vertical pumping term was estimated at about 5 Sv. F^rther, in the Southern Ocean, a significant reduction in subduction was estimated at around 24 Sv, indicating a substantial contribution to the weakening of global subduction.
基金Supported by National Foundation of Nature Science of China(No.10275063)
文摘Needs in scintimammography applications,especially for small animal cardiac imaging,lead to develop a small field of view,high spatial resolution gamma camera with a pinhole collimator.However the ideal pinhole collimator must keep a compromise between spatial resolution and sensitivity.In order to design a pinhole collimator with an optimized sensitivity and spatial resolution,the spatial resolution and the geometric sensitivity response as a function of the source to collimator distance has been obtained by means of Monte-Carlo simulation for a small field of view gamma camera with a pinhole collimator of various-hole diameters.The results show that the camera with pinhole of 1 mm,1.5 mm and 2 mm diameter has respectively spatial resolution of 1.5 mm,2.25 mm and 3 mm and geometric sensitivity of 0.016%,0.022%and 0.036%,while the source to collimator distance is 3 cm.We chose the pinhole collimator with hole diameter size of 1.2 mm for our the gamma camera designed based on the trade-off between sensitivity and resolution.
基金National Natural Science Foundation of China (No.10275063)
文摘A compact gamma-ray detector with good spatial resolution for emission computed tomography (E-CT) applications has been developed. The detector is composed of NaI(Tl) scintillation pixels array and Hamamastu R2486-05 PSPMT. Having a pixel size of 2 mm × 2 mm and an overall dimension of 48.2 mm × 48.2mm × 5 mm, it has 484 pixels in a 22×22 matrix. An average spatial resolution of 2.5mm (FWHM) was achieved. The slope of position linearity is constant within 10% in a range of 40mm. After corrections, the average value of differential non-linearity and absolute non-linearity were 0.16mm and 0.535mm respectively, and a 17% at FWHM of total energy resolution for 241Am was obtained.
基金supported by the Major State Basic Research Development Program of China (Grant no.2016YFA0601804)supported by the National Natural Science Foundation of China (Grant no.41876220)+3 种基金supported by the National Natural Science Foundation of China (Grant no.41806216)“the Fundamental Research Funds for the Central Universities” (Grant nos.2017B04814, 2017B20714)the Fundamental Research Funds for the Central Universities (Grant no.2013B18020192)by Project funded by China Postdoctoral Science Foundation (Grant nos.2019T120379, 2018M630499)
文摘At present,it is believed that the freezing point temperature of seawater is a function of salinity and pressure,and the freezing point is a key parameter in a coupled air-sea-ice system.Generally,empirical formulas or methods are used to calculate the freezing point of seawater.Especially in high-pressure situations,e.g.,under a thick ice sheet or ice shelf,the pressure term must be taken into account in the determination of seawater freezing point temperature.This study summarized various methods that have been used to calculate seawater freezing point with high pressure.The methods that were employed in two ocean-ice models were also assessed.We identified the disadvantages of these methods used in these two models and addressed the corresponding uncertainties of the freezing point temperature formulas.This study provides useful information on the calculation of the freezing point temperature in numerical modeling and indicates a need to investigate the sensitivity of numerical simulations to the uncertainties in the freezing point temperature in future.
