A key issue in the commercial aircraft engine design is environmental acceptability, and designers are continually challenged to reduce emissions. In this paper, an experimental investigation is performed to evaluate ...A key issue in the commercial aircraft engine design is environmental acceptability, and designers are continually challenged to reduce emissions. In this paper, an experimental investigation is performed to evaluate the emission performance of a liquid-fueled trapped vortex combustor （TVC） under lean premixed prevaporized （LPP） mode. When operating as an LPP system, a TVC is fueled both in the cavities and in the main stream. The correlations between the emission performance and the total ex- cess air ratio, the positions （4 positions） of the fuel injectors in the main stream, and the inlet temperature are obtained. Experimental results show that both the volume concentrations of unburnt hydrocarbon （UHC） and NOv （NO, NOxusually grouped together as NOx） increase with the increase of total excess air ratio from 1.5 to 3.0; the emission performance relies heavily on the position of the main stream injector, and the best perfomlance is achieved at Position 4 in the experiments, the increase of the inlet temperature impacts on the emission performance positively： the smallest volume concentrations of UHC and NO,. obtained in the experiment are 94×10^-6 and 2.3× 10 ^-6 respectively. This paper validates the feasibility of low emissions for an LPP/TVC and provides a reference for further optimization of TVCs.展开更多
This article briefly discusses the theoretical basis and overall goals of energy conservation in the steel manufacturing process system.It is proposed that in the process of implementing system energy conservation,it ...This article briefly discusses the theoretical basis and overall goals of energy conservation in the steel manufacturing process system.It is proposed that in the process of implementing system energy conservation,it is necessary to fully recognize and utilize the characteristics and functional advantages of the steel manufacturing process,pay more attention to energy quality,firmly grasp the overall goal of system optimization,focus on the integrated optimization of gas,steam,and waste heat systems,and propose the idea of constructing a"steel chemi-cal gas electricity heating cooling multi generation system".Based on practice,the main principles,models,and effects of implementing systematic energy conservation in steel enterprises have been proposed.展开更多
Psychiatric disorders have always attracted a lot of attention from researchers due to the difficulties in their diagnoses and treatments.Molecular imaging,as an emerging technology,has played an important role in the...Psychiatric disorders have always attracted a lot of attention from researchers due to the difficulties in their diagnoses and treatments.Molecular imaging,as an emerging technology,has played an important role in the researchers of various diseases.In recent years,molecular imaging techniques including magnetic resonance spectroscopy,nuclear medicine imaging,and fluorescence imaging have been widely used in the study of psychiatric disorders.This review will briefly summarize the progression of molecular imaging in psychiatric disorders.展开更多
The study examined the contamination levels of the soil and plantain leaves in three communities in Atakunmosa west local government area of Osun State in southwest Nigeria, where gold mining activities have recently ...The study examined the contamination levels of the soil and plantain leaves in three communities in Atakunmosa west local government area of Osun State in southwest Nigeria, where gold mining activities have recently become intensive. Plantain is a major food crop, whose leaves are used to wrap food items for household consumption. The objectives were to examine the heavy metal concentrations in the soil and plantain leaves around the gold mine site and compare them with standard recommended safe limits for the environment. Soil and plantain leaves were sampled at different locations around the sites and at a control site from a neighboring local government area with no history of gold mining activities between March 2015 and February 2016. Both soil and leave samples were processed and analyzed for selected heavy metals (Cd, As, Cu, Zn, Cr, Mn and Fe) using the Particle Induced X-ray Emission (PIXE) in the laboratory. The study showed higher concentrations than the World Health Organization’s recommended safe limits of the heavy metals in the soils and plantain leaves. Dry season concentrations of the variables were also higher than the wet season and the heavy metal concentrations at the control station were significantly (p < 0.05) lower than those of the mining environment. The study concluded that the ecosystems in the artisanal gold mining region are vulnerable to bioaccumulation of heavy metals and the leaves from the sites are sources of heavy metal contamination if consumed or used to wrap food items.展开更多
The reaction of CH radical with O2 has been experimentally investigated by time-resolved Fourier trans-form IR emission spectroscopy. CH radicals were generated by multi-photon UV laser photolysis of bromoform (CHBr3)...The reaction of CH radical with O2 has been experimentally investigated by time-resolved Fourier trans-form IR emission spectroscopy. CH radicals were generated by multi-photon UV laser photolysis of bromoform (CHBr3) in gaseous phase. Highly vibrationally excited product CO (v =1—12) with a near Boltzmann distribution was observed after the reaction. The vibrational temperature of CO is es-timated as high as 144001400 K and the averaged vibra-tional energy is about 25.8 kcalmol-1. The emission intensity of CO is not sensitive to the quenching gas, which indicates that there is no early barrier in the reaction of CH+O2. However, the theoretically predicted product CO2 has not been found in the experiment.展开更多
A system is described in which a graphite furnace electrothermal vaporization device is employed for the introduction of microlitre liquid sample into an inductively coupled argon plasma. The technique provides a pico...A system is described in which a graphite furnace electrothermal vaporization device is employed for the introduction of microlitre liquid sample into an inductively coupled argon plasma. The technique provides a picogram detection limit and an adequate precision with a relative standard deviation of 4%. Mechanism of analyte condensation in transport process is explored. As an application, the technique combined with DDTC/CCl4 extraction is used to enrich and determine non- rare earth impurities in highly pure La2O3.展开更多
Secondary copper production is one of the key polychlorinated dibenzo-p-dioxins and dibenzofurans （PCDD/Fs） emission sources in China, but research and data on this issue are rare. In 2004, when the Stockholm Conven...Secondary copper production is one of the key polychlorinated dibenzo-p-dioxins and dibenzofurans （PCDD/Fs） emission sources in China, but research and data on this issue are rare. In 2004, when the Stockholm Convention entered into force in China, PCDD/Fs emissions from secondary copper production contributed to 32.2% of the total release. In this paper, PCDD/Fs emission dynamics from secondary copper industry were discussed and cumulative risks were characterized. From 2004 to 2009, industrial policies played an indirect role in PCDD/Fs reduction, but its effects are still limited. The Yangtze River Delta, Pearl River Delta and central regions were among the top three of dioxin emissions from secondary copper production in China. Shanghai, Shan- dong, Zhejiang, and Jiangxi had comparatively higher accumulated risk and were recommended as the priority regions for promoting PCDD/Fs emission control in China. From 2009 to 2015, the PCDD/Fs emission dynamics in the secondary copper industry were presented through simulation. PCDD/Fs emission equations were established, resulting in the recommendation of control technology conversion rate at 30% for small scale smelters and 51%- 57% for large and medium-sized enterprises in 2015. In conclusion, both indirect policy and direct control technology retrofitting should be integrated for more effective PCDD/Fs emission reduction in secondary copper industry.展开更多
This work evaluates the influence of energy consumption on the future air quality in Beijing,using 2000 as the base year and 2008 as the target year.It establishes the emission inventory of primary PM_(10),SO_(2) and ...This work evaluates the influence of energy consumption on the future air quality in Beijing,using 2000 as the base year and 2008 as the target year.It establishes the emission inventory of primary PM_(10),SO_(2) and NO_(x) related to energy utilization in eight areas of Beijing.The air quality model was adopted to simulate the temporal and spatial distribution of each pollutant concentration in the eight urban areas.Their emission,concentration distribution,and sectoral share responsibility rate were analyzed,and air quality in 2008 was predicted.The industrial sector contributed above 40% of primary PM_(10) and SO_(2) resulting from energy consumption,while vehicles accounted for about 65% of NO_(x).According to the current policy and development trend,air quality in the eight urban areas could become better in 2008 when the average concentrations of primary PM_(10),SO_(2) and NO_(2) related to energy utilization at each monitored site are predicted to be about 25,50 and 51μg/m^(3),respectively.展开更多
基金Aeronautical Science Foundation of China(2008ZB52013)Funding of Jiangsu Innovation Program for Graduate Education(CXLX11_0211)
文摘A key issue in the commercial aircraft engine design is environmental acceptability, and designers are continually challenged to reduce emissions. In this paper, an experimental investigation is performed to evaluate the emission performance of a liquid-fueled trapped vortex combustor （TVC） under lean premixed prevaporized （LPP） mode. When operating as an LPP system, a TVC is fueled both in the cavities and in the main stream. The correlations between the emission performance and the total ex- cess air ratio, the positions （4 positions） of the fuel injectors in the main stream, and the inlet temperature are obtained. Experimental results show that both the volume concentrations of unburnt hydrocarbon （UHC） and NOv （NO, NOxusually grouped together as NOx） increase with the increase of total excess air ratio from 1.5 to 3.0; the emission performance relies heavily on the position of the main stream injector, and the best perfomlance is achieved at Position 4 in the experiments, the increase of the inlet temperature impacts on the emission performance positively： the smallest volume concentrations of UHC and NO,. obtained in the experiment are 94×10^-6 and 2.3× 10 ^-6 respectively. This paper validates the feasibility of low emissions for an LPP/TVC and provides a reference for further optimization of TVCs.
文摘This article briefly discusses the theoretical basis and overall goals of energy conservation in the steel manufacturing process system.It is proposed that in the process of implementing system energy conservation,it is necessary to fully recognize and utilize the characteristics and functional advantages of the steel manufacturing process,pay more attention to energy quality,firmly grasp the overall goal of system optimization,focus on the integrated optimization of gas,steam,and waste heat systems,and propose the idea of constructing a"steel chemi-cal gas electricity heating cooling multi generation system".Based on practice,the main principles,models,and effects of implementing systematic energy conservation in steel enterprises have been proposed.
基金supported by the Sichuan Foundation for Distinguished Young Scholars (Grant 2022JDJQ0049)the Scientific and Tec hnological Achievements Transformation Fund of West China Hospital,Sichuan University (Grant CGZH21002)the Innovative Research Project of Sichuan University (Grant 2022SCUH00132).
文摘Psychiatric disorders have always attracted a lot of attention from researchers due to the difficulties in their diagnoses and treatments.Molecular imaging,as an emerging technology,has played an important role in the researchers of various diseases.In recent years,molecular imaging techniques including magnetic resonance spectroscopy,nuclear medicine imaging,and fluorescence imaging have been widely used in the study of psychiatric disorders.This review will briefly summarize the progression of molecular imaging in psychiatric disorders.
文摘The study examined the contamination levels of the soil and plantain leaves in three communities in Atakunmosa west local government area of Osun State in southwest Nigeria, where gold mining activities have recently become intensive. Plantain is a major food crop, whose leaves are used to wrap food items for household consumption. The objectives were to examine the heavy metal concentrations in the soil and plantain leaves around the gold mine site and compare them with standard recommended safe limits for the environment. Soil and plantain leaves were sampled at different locations around the sites and at a control site from a neighboring local government area with no history of gold mining activities between March 2015 and February 2016. Both soil and leave samples were processed and analyzed for selected heavy metals (Cd, As, Cu, Zn, Cr, Mn and Fe) using the Particle Induced X-ray Emission (PIXE) in the laboratory. The study showed higher concentrations than the World Health Organization’s recommended safe limits of the heavy metals in the soils and plantain leaves. Dry season concentrations of the variables were also higher than the wet season and the heavy metal concentrations at the control station were significantly (p < 0.05) lower than those of the mining environment. The study concluded that the ecosystems in the artisanal gold mining region are vulnerable to bioaccumulation of heavy metals and the leaves from the sites are sources of heavy metal contamination if consumed or used to wrap food items.
文摘The reaction of CH radical with O2 has been experimentally investigated by time-resolved Fourier trans-form IR emission spectroscopy. CH radicals were generated by multi-photon UV laser photolysis of bromoform (CHBr3) in gaseous phase. Highly vibrationally excited product CO (v =1—12) with a near Boltzmann distribution was observed after the reaction. The vibrational temperature of CO is es-timated as high as 144001400 K and the averaged vibra-tional energy is about 25.8 kcalmol-1. The emission intensity of CO is not sensitive to the quenching gas, which indicates that there is no early barrier in the reaction of CH+O2. However, the theoretically predicted product CO2 has not been found in the experiment.
文摘A system is described in which a graphite furnace electrothermal vaporization device is employed for the introduction of microlitre liquid sample into an inductively coupled argon plasma. The technique provides a picogram detection limit and an adequate precision with a relative standard deviation of 4%. Mechanism of analyte condensation in transport process is explored. As an application, the technique combined with DDTC/CCl4 extraction is used to enrich and determine non- rare earth impurities in highly pure La2O3.
文摘Secondary copper production is one of the key polychlorinated dibenzo-p-dioxins and dibenzofurans （PCDD/Fs） emission sources in China, but research and data on this issue are rare. In 2004, when the Stockholm Convention entered into force in China, PCDD/Fs emissions from secondary copper production contributed to 32.2% of the total release. In this paper, PCDD/Fs emission dynamics from secondary copper industry were discussed and cumulative risks were characterized. From 2004 to 2009, industrial policies played an indirect role in PCDD/Fs reduction, but its effects are still limited. The Yangtze River Delta, Pearl River Delta and central regions were among the top three of dioxin emissions from secondary copper production in China. Shanghai, Shan- dong, Zhejiang, and Jiangxi had comparatively higher accumulated risk and were recommended as the priority regions for promoting PCDD/Fs emission control in China. From 2009 to 2015, the PCDD/Fs emission dynamics in the secondary copper industry were presented through simulation. PCDD/Fs emission equations were established, resulting in the recommendation of control technology conversion rate at 30% for small scale smelters and 51%- 57% for large and medium-sized enterprises in 2015. In conclusion, both indirect policy and direct control technology retrofitting should be integrated for more effective PCDD/Fs emission reduction in secondary copper industry.
基金This work was supported by the Foundation of the World Bank and Global Environment Facility(Grant No.60K04772).
文摘This work evaluates the influence of energy consumption on the future air quality in Beijing,using 2000 as the base year and 2008 as the target year.It establishes the emission inventory of primary PM_(10),SO_(2) and NO_(x) related to energy utilization in eight areas of Beijing.The air quality model was adopted to simulate the temporal and spatial distribution of each pollutant concentration in the eight urban areas.Their emission,concentration distribution,and sectoral share responsibility rate were analyzed,and air quality in 2008 was predicted.The industrial sector contributed above 40% of primary PM_(10) and SO_(2) resulting from energy consumption,while vehicles accounted for about 65% of NO_(x).According to the current policy and development trend,air quality in the eight urban areas could become better in 2008 when the average concentrations of primary PM_(10),SO_(2) and NO_(2) related to energy utilization at each monitored site are predicted to be about 25,50 and 51μg/m^(3),respectively.
