Following the progress of satellite data assimilation in the 1990s, the combination of meteorological satellites and numerical models has changed the way scientists understand the earth. With the evolution of numerica...Following the progress of satellite data assimilation in the 1990s, the combination of meteorological satellites and numerical models has changed the way scientists understand the earth. With the evolution of numerical weather prediction models and earth system models, meteorological satellites will play a more important role in earth sciences in the future. As part of the space-based infrastructure, the Fengyun (FY) meteorological satellites have contributed to earth science sustainability studies through an open data policy and stable data quality since the first launch of the FY-1A satellite in 1988. The capability of earth system monitoring was greatly enhanced after the second-generation polar orbiting FY-3 satellites and geostationary orbiting FY-4 satellites were developed. Meanwhile, the quality of the products generated from the FY-3 and FY-4 satellites is comparable to the well-known MODIS products. FY satellite data has been utilized broadly in weather forecasting, climate and climate change investigations, environmental disaster monitoring, etc. This article reviews the instruments mounted on the FY satellites. Sensor-dependent level 1 products (radiance data) and inversion algorithm-dependent level 2 products (geophysical parameters) are introduced. As an example, some typical geophysical parameters, such as wildfires, lightning, vegetation indices, aerosol products, soil moisture, and precipitation estimation have been demonstrated and validated by in-situ observations and other well-known satellite products. To help users access the FY products, a set of data sharing systems has been developed and operated. The newly developed data sharing system based on cloud technology has been illustrated to improve the efficiency of data delivery.展开更多
Research on level 2 control system of 100 tons LF furnace was carried out. According to the principle of energy conservation and principle of mass conservation, the LF temperature prediction model and the composition ...Research on level 2 control system of 100 tons LF furnace was carried out. According to the principle of energy conservation and principle of mass conservation, the LF temperature prediction model and the composition prediction model were established. At the same time, the set value calculated by heating model and addition model could be sent to PLC. The results show that the technical indexes of LF furnace level 2 control system reach the demand and the system realizes automatic control.展开更多
The peculiar photoconduction in semi insulating GaAs photoconductive switch being triggered by 1064nm laser pulse is reported.The gap between two electrodes of the switch is 4mm.When it is triggered by laser pulse wi...The peculiar photoconduction in semi insulating GaAs photoconductive switch being triggered by 1064nm laser pulse is reported.The gap between two electrodes of the switch is 4mm.When it is triggered by laser pulse with energy of 0 8mJ and the pulse width of 5ns,and operated at biased electric field of 2 0 and 6 0kV/cm,both linear and nonlinear modes of the switch are observed respectively.Whereas the biased electric field adds to 9 5kV/cm,and the triggered laser is in range of 0 5～1 0mJ,the peculiar performed characteristic is observed:the switch gives a linear waveform firstly,and then after a delay time of about 20～250ns,it outputs a nonlinear waveform again.The physical mechanism of this specific phenomenon is associated with the anti site defects of semi insulating GaAs and two step single photon absorption.The delay time between linear waveform and nonlinear waveform is calculated,and the result matches the experiments.展开更多
Gallium arsenide (GaAs) photoconductive semiconductor switches (PCSS's) with a 1.55mm gap spacing trigged by 1553nm femtosecond fiber laser pulse is presented.The switches are biased with 3.33～10.3kV/cm and irrad...Gallium arsenide (GaAs) photoconductive semiconductor switches (PCSS's) with a 1.55mm gap spacing trigged by 1553nm femtosecond fiber laser pulse is presented.The switches are biased with 3.33～10.3kV/cm and irradiated by femtosecond fiber laser operated at a wavelength of 1553nm with pulse width of 200fs and pulse energy of 0.2nJ.The experiments show that,even if the semi-insulating GaAs photoconductive switch operates under the electrical field of 10.3kV/cm,it will be still linear response,and a clear corresponding output electric pulse with the peak voltage of 0.8mV is captured.From the weak photoconductivity on laser intensity,photoabsorption mediated by EL2 deep level defects is suggested,as the primary process for the photoconductivity.展开更多
This study was conducted to investigate the combined effects of elevated CO2 levels and cadmium (Cd) on the root morphological traits and Cd accumulation in Lolium multiflorum Lam.and Lolium perenne L.exposed to two C...This study was conducted to investigate the combined effects of elevated CO2 levels and cadmium (Cd) on the root morphological traits and Cd accumulation in Lolium multiflorum Lam.and Lolium perenne L.exposed to two CO2 levels (360 and 1000 μl/L) and three Cd levels (0,4,and 16 mg/L) under hydroponic conditions.The results show that elevated levels of CO2 increased shoot biomass more,compared to root biomass,but decreased Cd concentrations in all plant tissues.Cd exposure caused toxicity to both Lolium species,as shown by the restrictions of the root morphological parameters including root length,surface area,volume,and tip numbers.These parameters were significantly higher under elevated levels of CO2 than under ambient CO2,especially for the number of fine roots.The increases in magnitudes of those parameters triggered by elevated levels of CO2 under Cd stress were more than those under non-Cd stress,suggesting an ameliorated Cd stress under elevated levels of CO2.The total Cd uptake per pot,calculated on the basis of biomass,was significantly greater under elevated levels of CO2 than under ambient CO2.Ameliorated Cd toxicity,decreased Cd concentration,and altered root morphological traits in both Lolium species under elevated levels of CO2 may have implications in food safety and phytoremediation.展开更多
A series of 17-yr equilibrium simulations using the NCAR COM3 (T42resolution) were performed to investigate the regional scale impacts of land cover change andincreasing CO_2 over China. Simulations with natural and c...A series of 17-yr equilibrium simulations using the NCAR COM3 (T42resolution) were performed to investigate the regional scale impacts of land cover change andincreasing CO_2 over China. Simulations with natural and current land cover at CO_2 levels of 280,355, 430, and 505 ppmv were conducted. Results show statistically significant changes in majorclimate fields (e.g. temperature and surface wind speed) on a 15-yr average following land coverchange. We also found increases in the maximum temperature and in the diurnal temperature range dueto land cover change. Increases in CO_2 affect both the maximum and minimum temperature so thatchanges in the diurnal range are small. Both land cover change and CO_2 change also impact thefrequency distribution of precipitation with increasing CO_2 tending to lead to more intenseprecipitation and land cover change leading to less intense precipitation―indeed, the impact ofland cover change typically had the opposite effect versus the impacts of CO_2. Our results providesupport for the inclusion of future land cover change scenarios in long-term transitory climatemodelling experiments of the 21st Century. Our results also support the inclusion of land surfacemodels that can represent future land cover changes resulting from an ecological response to naturalclimate variability or increasing CO_2. Overall, we show that land cover change can have asignificant impact on the regional scale climate of China, and that regionally, this impact is of asimilar magnitude to increases in CO_2 of up to about 430 ppmv. This means that that the impact ofland cover change must be accounted for in detection and attribution studies over China.展开更多
To establish the parsimonious model for blood glucose monitoring in patients with type 2 diabetes receiving oral hypoglycemic agent treatment. One hundred and fifty-nine adult Chinese type 2 diabetes patients were ran...To establish the parsimonious model for blood glucose monitoring in patients with type 2 diabetes receiving oral hypoglycemic agent treatment. One hundred and fifty-nine adult Chinese type 2 diabetes patients were randomized to receive rapid-acting or sustained-release gliclazide therapy for 12 weeks.展开更多
Concern about the biological hazards involved in microbiological research, especially research involving laboratory animals, has increased in recent years. Working in an animal biosafety level 2 facility （ABSL-2）, c...Concern about the biological hazards involved in microbiological research, especially research involving laboratory animals, has increased in recent years. Working in an animal biosafety level 2 facility （ABSL-2）, commonly used for research on infectious diseases, poses various biological hazards. Here, the regulations and standards related to laboratory biosafety in China are introduced, the potential biological hazards present in ABSL-2 facilities are analyzed, and a series of strategies to control the hazards are presented.展开更多
Given is the experiment results in which the laser pulses of 1 046 nm and 532 nm are used to trigger the semi-insulation GaAs photoconductive semiconductor switch(PCSS) with an electrode distance of 4 mm. And made is ...Given is the experiment results in which the laser pulses of 1 046 nm and 532 nm are used to trigger the semi-insulation GaAs photoconductive semiconductor switch(PCSS) with an electrode distance of 4 mm. And made is an analysis of the switchs photovoltaic response characteristics under the high gain mode when the biased field is bigger than the Geng effect field. Also a theory is presented that the main reason for the photovoltaic pulse response delay is the transmission of charge domain, caused by the presence of EL2 energy level in the chip material. Finally, the transmission time of charge domain is calculated and a result that inosculates with the experiment is attained.展开更多
BACKGROUND MMP-2 also known as gelatinase A and MMP-7(matrilysin)are members of the zinc-dependent family of MMPs(Matrix metalloproteinase).MMP-2 and MMP-7 are remodeling enzymes that digest extracellular matrix;MMP-2...BACKGROUND MMP-2 also known as gelatinase A and MMP-7(matrilysin)are members of the zinc-dependent family of MMPs(Matrix metalloproteinase).MMP-2 and MMP-7 are remodeling enzymes that digest extracellular matrix;MMP-2 is extensively expressed during development and is upregulated at sites of tissue damage,inflammation,and in stromal cells of metastatic tumors.MMP-7 is expressed in the epithelial cells and in a variety of cancers including colon tumors.Plasma MMP-2 and MMP-7 levels were assessed before and after minimally invasive colorectal resection for cancer pathology.AIM To determine plasma MMP-2 and MMP-7 levels before and after minimally invasive colorectal resection for cancer pathology.METHODS Patients enrolled in a plasma bank for whom plasma was available were eligible.Plasma obtained from preoperative(Preop)and postoperative blood samples was used.Only colorectal cancer(CRC)patients who underwent elective minimally invasive cancer resection with preop,post-operative day(POD)1,3 and at least 1 late postop sample(POD 7-34)were included.Late samples were bundled into 7 d blocks(POD 7-13,14-20,etc.)and treated as single time points.Plasma MMP-2 and MMP-7 levels were determined via enzyme-linked immunosorbent assay in duplicate.RESULTS Total 88 minimally invasive CRC resection CRC patients were studied(right colectomy,37%;sigmoid,24%;and LAR/AR 18%).Cancer stages were:1,31%;2,30%;3,34%;and 4,5%.Mean Preop MMP-2 plasma level(ng/mL)was 179.3±40.9(n=88).Elevated mean levels were noted on POD1(214.3±51.2,n=87,P<0.001),POD3(258.0±63.9,n=80,P<0.001),POD7-13(229.9±62.3,n=65,P<0.001),POD 14-20(234.9±47.5,n=25,P<0.001),POD 21-27(237.0±63.5,n=17,P<0.001,)and POD 28-34(255.4±59.7,n=15,P<0.001).Mean Preop MMP-7 level was 3.9±1.9(n=88).No significant differences were noted on POD 1 or 3,however,significantly elevated levels were noted on POD 7-13(5.7±2.5,n=65,P<0.001),POD 14-20(5.9±2.5,n=25,P<0.001),POD 21-27(6.1±3.6,n=17,P=0.002)and on POD 28-34(6.8±3.3,n=15 P<0.001,)vs preop levels.CONCLUSION MMP-2 levels are elevated for 5 wk and MMP-7 levels elevated for weeks 2-6.The etiology of these changes in unclear,trauma and wound healing likely play a role.These changes may promote residual tumor growth and metastasis.展开更多
Many new steel plate processing facilities have been built in the past 10 years around the world with many more being planned for the future.This is especially true in developing countries such as China,India and Braz...Many new steel plate processing facilities have been built in the past 10 years around the world with many more being planned for the future.This is especially true in developing countries such as China,India and Brazil.Many of these facilities are plate mills with either one or two stands or a Steckel mill,typically only one stand designed for the production of structural plate steels.Unfortunately,there is a lack of understanding with both the mill builders of the world and the mill owners on the importance of properly matching up the available slab supply (either new as part of a new plate/Steckel mill complex or part of an already existing) with the desired end plate product mix.Many mill builders and owners around the world believe that you can take any slab of any dimension and make any plate dimension you want.While this is basically true with today’s Level 2 automation systems,it does not always result in optimum metallurgy/mechanical properties or productivity.This less than optimum condition results in mechanical property failures,shape issues,productivity losses and in general a less than desirable costly processing operation.It is important to the overall optimization of a steel processing facility that the proper slab dimensions be used to produce the proper final plate dimensions along with achieving the required mechanical properties.The critical nature of this selection will be dependent on the final plate thickness and overall mechanical property requirements.Proper mechanical property,shape and overall microstructure are heavily dependent on the ability to properly work the entire cross section of the slab through the rolling process.Many mechanical property,shape and microstructural issues are a result of improper working of the entire cross section during rolling.The ability for a given mill to properly work the entire cross section is dependent on proper slab selection (total reduction ratio) and a proper rolling schedule either generated manually by the operator or by the mills Level 2 automation system.The proper working and more importantly the true metallurgy of the slab being rolled does not occur until any dimensional rolling passes have been completed.In fact,dimensional rolling passes may create a negative situation that will have to be overcome in the remainder of the rolling schedule.This paper will discuss the importance of proper slab selection for a given plate dimension and final product.Examples and guidelines will be given related to proper slab selection for final plate dimensions and mechanical property requirements.展开更多
基金This work was supported by the National Key Research and Development Program of China(2018YFB0504900,2018YFB0504905).
文摘Following the progress of satellite data assimilation in the 1990s, the combination of meteorological satellites and numerical models has changed the way scientists understand the earth. With the evolution of numerical weather prediction models and earth system models, meteorological satellites will play a more important role in earth sciences in the future. As part of the space-based infrastructure, the Fengyun (FY) meteorological satellites have contributed to earth science sustainability studies through an open data policy and stable data quality since the first launch of the FY-1A satellite in 1988. The capability of earth system monitoring was greatly enhanced after the second-generation polar orbiting FY-3 satellites and geostationary orbiting FY-4 satellites were developed. Meanwhile, the quality of the products generated from the FY-3 and FY-4 satellites is comparable to the well-known MODIS products. FY satellite data has been utilized broadly in weather forecasting, climate and climate change investigations, environmental disaster monitoring, etc. This article reviews the instruments mounted on the FY satellites. Sensor-dependent level 1 products (radiance data) and inversion algorithm-dependent level 2 products (geophysical parameters) are introduced. As an example, some typical geophysical parameters, such as wildfires, lightning, vegetation indices, aerosol products, soil moisture, and precipitation estimation have been demonstrated and validated by in-situ observations and other well-known satellite products. To help users access the FY products, a set of data sharing systems has been developed and operated. The newly developed data sharing system based on cloud technology has been illustrated to improve the efficiency of data delivery.
文摘Research on level 2 control system of 100 tons LF furnace was carried out. According to the principle of energy conservation and principle of mass conservation, the LF temperature prediction model and the composition prediction model were established. At the same time, the set value calculated by heating model and addition model could be sent to PLC. The results show that the technical indexes of LF furnace level 2 control system reach the demand and the system realizes automatic control.
文摘The peculiar photoconduction in semi insulating GaAs photoconductive switch being triggered by 1064nm laser pulse is reported.The gap between two electrodes of the switch is 4mm.When it is triggered by laser pulse with energy of 0 8mJ and the pulse width of 5ns,and operated at biased electric field of 2 0 and 6 0kV/cm,both linear and nonlinear modes of the switch are observed respectively.Whereas the biased electric field adds to 9 5kV/cm,and the triggered laser is in range of 0 5～1 0mJ,the peculiar performed characteristic is observed:the switch gives a linear waveform firstly,and then after a delay time of about 20～250ns,it outputs a nonlinear waveform again.The physical mechanism of this specific phenomenon is associated with the anti site defects of semi insulating GaAs and two step single photon absorption.The delay time between linear waveform and nonlinear waveform is calculated,and the result matches the experiments.
文摘Gallium arsenide (GaAs) photoconductive semiconductor switches (PCSS's) with a 1.55mm gap spacing trigged by 1553nm femtosecond fiber laser pulse is presented.The switches are biased with 3.33～10.3kV/cm and irradiated by femtosecond fiber laser operated at a wavelength of 1553nm with pulse width of 200fs and pulse energy of 0.2nJ.The experiments show that,even if the semi-insulating GaAs photoconductive switch operates under the electrical field of 10.3kV/cm,it will be still linear response,and a clear corresponding output electric pulse with the peak voltage of 0.8mV is captured.From the weak photoconductivity on laser intensity,photoabsorption mediated by EL2 deep level defects is suggested,as the primary process for the photoconductivity.
基金Project supported by the Central Public Research Institute Basic Fund for Research and Development (2008-jxh-1),Agro-environmental Protection Institute,Ministry of Agriculture,China
文摘This study was conducted to investigate the combined effects of elevated CO2 levels and cadmium (Cd) on the root morphological traits and Cd accumulation in Lolium multiflorum Lam.and Lolium perenne L.exposed to two CO2 levels (360 and 1000 μl/L) and three Cd levels (0,4,and 16 mg/L) under hydroponic conditions.The results show that elevated levels of CO2 increased shoot biomass more,compared to root biomass,but decreased Cd concentrations in all plant tissues.Cd exposure caused toxicity to both Lolium species,as shown by the restrictions of the root morphological parameters including root length,surface area,volume,and tip numbers.These parameters were significantly higher under elevated levels of CO2 than under ambient CO2,especially for the number of fine roots.The increases in magnitudes of those parameters triggered by elevated levels of CO2 under Cd stress were more than those under non-Cd stress,suggesting an ameliorated Cd stress under elevated levels of CO2.The total Cd uptake per pot,calculated on the basis of biomass,was significantly greater under elevated levels of CO2 than under ambient CO2.Ameliorated Cd toxicity,decreased Cd concentration,and altered root morphological traits in both Lolium species under elevated levels of CO2 may have implications in food safety and phytoremediation.
文摘A series of 17-yr equilibrium simulations using the NCAR COM3 (T42resolution) were performed to investigate the regional scale impacts of land cover change andincreasing CO_2 over China. Simulations with natural and current land cover at CO_2 levels of 280,355, 430, and 505 ppmv were conducted. Results show statistically significant changes in majorclimate fields (e.g. temperature and surface wind speed) on a 15-yr average following land coverchange. We also found increases in the maximum temperature and in the diurnal temperature range dueto land cover change. Increases in CO_2 affect both the maximum and minimum temperature so thatchanges in the diurnal range are small. Both land cover change and CO_2 change also impact thefrequency distribution of precipitation with increasing CO_2 tending to lead to more intenseprecipitation and land cover change leading to less intense precipitation―indeed, the impact ofland cover change typically had the opposite effect versus the impacts of CO_2. Our results providesupport for the inclusion of future land cover change scenarios in long-term transitory climatemodelling experiments of the 21st Century. Our results also support the inclusion of land surfacemodels that can represent future land cover changes resulting from an ecological response to naturalclimate variability or increasing CO_2. Overall, we show that land cover change can have asignificant impact on the regional scale climate of China, and that regionally, this impact is of asimilar magnitude to increases in CO_2 of up to about 430 ppmv. This means that that the impact ofland cover change must be accounted for in detection and attribution studies over China.
文摘To establish the parsimonious model for blood glucose monitoring in patients with type 2 diabetes receiving oral hypoglycemic agent treatment. One hundred and fifty-nine adult Chinese type 2 diabetes patients were randomized to receive rapid-acting or sustained-release gliclazide therapy for 12 weeks.
基金supported by the National Science and Technology Major Projects of Infectious Disease(2012ZX10004-404)
文摘Concern about the biological hazards involved in microbiological research, especially research involving laboratory animals, has increased in recent years. Working in an animal biosafety level 2 facility （ABSL-2）, commonly used for research on infectious diseases, poses various biological hazards. Here, the regulations and standards related to laboratory biosafety in China are introduced, the potential biological hazards present in ABSL-2 facilities are analyzed, and a series of strategies to control the hazards are presented.
文摘Given is the experiment results in which the laser pulses of 1 046 nm and 532 nm are used to trigger the semi-insulation GaAs photoconductive semiconductor switch(PCSS) with an electrode distance of 4 mm. And made is an analysis of the switchs photovoltaic response characteristics under the high gain mode when the biased field is bigger than the Geng effect field. Also a theory is presented that the main reason for the photovoltaic pulse response delay is the transmission of charge domain, caused by the presence of EL2 energy level in the chip material. Finally, the transmission time of charge domain is calculated and a result that inosculates with the experiment is attained.
文摘BACKGROUND MMP-2 also known as gelatinase A and MMP-7(matrilysin)are members of the zinc-dependent family of MMPs(Matrix metalloproteinase).MMP-2 and MMP-7 are remodeling enzymes that digest extracellular matrix;MMP-2 is extensively expressed during development and is upregulated at sites of tissue damage,inflammation,and in stromal cells of metastatic tumors.MMP-7 is expressed in the epithelial cells and in a variety of cancers including colon tumors.Plasma MMP-2 and MMP-7 levels were assessed before and after minimally invasive colorectal resection for cancer pathology.AIM To determine plasma MMP-2 and MMP-7 levels before and after minimally invasive colorectal resection for cancer pathology.METHODS Patients enrolled in a plasma bank for whom plasma was available were eligible.Plasma obtained from preoperative(Preop)and postoperative blood samples was used.Only colorectal cancer(CRC)patients who underwent elective minimally invasive cancer resection with preop,post-operative day(POD)1,3 and at least 1 late postop sample(POD 7-34)were included.Late samples were bundled into 7 d blocks(POD 7-13,14-20,etc.)and treated as single time points.Plasma MMP-2 and MMP-7 levels were determined via enzyme-linked immunosorbent assay in duplicate.RESULTS Total 88 minimally invasive CRC resection CRC patients were studied(right colectomy,37%;sigmoid,24%;and LAR/AR 18%).Cancer stages were:1,31%;2,30%;3,34%;and 4,5%.Mean Preop MMP-2 plasma level(ng/mL)was 179.3±40.9(n=88).Elevated mean levels were noted on POD1(214.3±51.2,n=87,P<0.001),POD3(258.0±63.9,n=80,P<0.001),POD7-13(229.9±62.3,n=65,P<0.001),POD 14-20(234.9±47.5,n=25,P<0.001),POD 21-27(237.0±63.5,n=17,P<0.001,)and POD 28-34(255.4±59.7,n=15,P<0.001).Mean Preop MMP-7 level was 3.9±1.9(n=88).No significant differences were noted on POD 1 or 3,however,significantly elevated levels were noted on POD 7-13(5.7±2.5,n=65,P<0.001),POD 14-20(5.9±2.5,n=25,P<0.001),POD 21-27(6.1±3.6,n=17,P=0.002)and on POD 28-34(6.8±3.3,n=15 P<0.001,)vs preop levels.CONCLUSION MMP-2 levels are elevated for 5 wk and MMP-7 levels elevated for weeks 2-6.The etiology of these changes in unclear,trauma and wound healing likely play a role.These changes may promote residual tumor growth and metastasis.
文摘Many new steel plate processing facilities have been built in the past 10 years around the world with many more being planned for the future.This is especially true in developing countries such as China,India and Brazil.Many of these facilities are plate mills with either one or two stands or a Steckel mill,typically only one stand designed for the production of structural plate steels.Unfortunately,there is a lack of understanding with both the mill builders of the world and the mill owners on the importance of properly matching up the available slab supply (either new as part of a new plate/Steckel mill complex or part of an already existing) with the desired end plate product mix.Many mill builders and owners around the world believe that you can take any slab of any dimension and make any plate dimension you want.While this is basically true with today’s Level 2 automation systems,it does not always result in optimum metallurgy/mechanical properties or productivity.This less than optimum condition results in mechanical property failures,shape issues,productivity losses and in general a less than desirable costly processing operation.It is important to the overall optimization of a steel processing facility that the proper slab dimensions be used to produce the proper final plate dimensions along with achieving the required mechanical properties.The critical nature of this selection will be dependent on the final plate thickness and overall mechanical property requirements.Proper mechanical property,shape and overall microstructure are heavily dependent on the ability to properly work the entire cross section of the slab through the rolling process.Many mechanical property,shape and microstructural issues are a result of improper working of the entire cross section during rolling.The ability for a given mill to properly work the entire cross section is dependent on proper slab selection (total reduction ratio) and a proper rolling schedule either generated manually by the operator or by the mills Level 2 automation system.The proper working and more importantly the true metallurgy of the slab being rolled does not occur until any dimensional rolling passes have been completed.In fact,dimensional rolling passes may create a negative situation that will have to be overcome in the remainder of the rolling schedule.This paper will discuss the importance of proper slab selection for a given plate dimension and final product.Examples and guidelines will be given related to proper slab selection for final plate dimensions and mechanical property requirements.
