Sludge is the by-product of wastewater treatment process. Multisource sludge can be defined as sludge from different sources. Based on the sludge properties of five typical cities in the Yangtze River basin, including...Sludge is the by-product of wastewater treatment process. Multisource sludge can be defined as sludge from different sources. Based on the sludge properties of five typical cities in the Yangtze River basin, including Jiujiang, Wuhu, Lu’an, Zhenjiang and Wuhan, this study investigated and summarized the characteristic variations and distribution differences of multiple indicators and substances from municipal sludge, dredged sludge, and river and lake sediments. The results demonstrated pH of multisource sludge was relatively stable in the neutral range. Organic matter and water content among municipal sludge were high and varied considerably between different wastewater treatment plants. Dredged sludge had an obviously higher sand content and wider particle distribution, which could be considered for graded utilization depending on its size. The nutrients composition of river and lake sediments was usually stable and special, with lower nitrogen and phosphorus content but higher potassium levels. The sources of heavy metals and persistent organic pollutants in multisource sludge were correlated, generally much higher among municipal sludge than dredged sludge and river and lake sediments, which were the most important limitation for final land utilization. Despite various properties of multisource sludge, the final fate and destination have some overall similarities, which need to be supplemented and improved by standards and laws. The study provided a preliminary analysis of suitable technical routes for municipal sludge, dredged sludge, river and lake sediments based on their different characteristics respectively, which was of great significance for multisource sludge co-treatment and disposal in the future of China.展开更多
As an important intermediate product, short-chain fatty acids（SCFAs） can be generated after hydrolysis and acidification from waste activated sludge, and then can be transformed to methane during anaerobic digestion...As an important intermediate product, short-chain fatty acids（SCFAs） can be generated after hydrolysis and acidification from waste activated sludge, and then can be transformed to methane during anaerobic digestion process. In order to obtain more SCFA and methane,most studies in literatures were centered on enhancing the hydrolysis of sludge anaerobic digestion which was proved as un-efficient. Though the alkaline pretreatment in our previous study increased both the hydrolysis and acidification processes, it had a vast chemical cost which was considered uneconomical. In this paper, a low energy consumption pretreatment method, i.e. enhanced the whole three stages of the anaerobic fermentation processes at the same time, was reported, by which hydrolysis and acidification were both enhanced, and the SCFA and methane generation can be significantly improved with a small quantity of chemical input. Firstly, the effect of different pretreated temperatures and pretreatment time on sludge hydrolyzation was compared. It was found that sludge pretreated at 100°C for 60 min can achieve the maximal hydrolyzation. Further, effects of different initial p Hs on acidification of the thermal pretreated sludge were investigated and the highest SCFA was observed at initial p H 9.0with fermentation time of 6 d, the production of which was 348.63 mg COD/g VSS（6.8 times higher than the blank test） and the acetic acid was dominant acid. Then, the mechanisms for this new pretreatment significantly improving SCFA production were discussed. Finally,the effect of this low energy consumption pretreatment on methane generation was investigated.展开更多
This year,the number college graduates in China surpassed tens of millions for the first time.The employment rate of fresh graduates has been concerning.In view of this,network entrepreneurship has become an important...This year,the number college graduates in China surpassed tens of millions for the first time.The employment rate of fresh graduates has been concerning.In view of this,network entrepreneurship has become an important channel and platform to solve the problem of college students’employment.The government,society and universities has been actively encouraging college students'network entrepreneurship as the value of college students'network entrepreneurship is significant.This paper analyzes the current situation of college students'network entrepreneurship and the problems faced through the survey data and thus suggests corresponding countermeasures.展开更多
To meet the demands for seamless medium-and short-range weather forecasting during the Beijing Winter Olympics(2022),the Winter Olympics research team at the Earth System Modeling and Prediction Centre(CEMC)of the Chi...To meet the demands for seamless medium-and short-range weather forecasting during the Beijing Winter Olympics(2022),the Winter Olympics research team at the Earth System Modeling and Prediction Centre(CEMC)of the China Meteorological Administration(CMA)developed an integrated global and regional numerical weather prediction(NWP)model system.In support of the Winter Olympics,the system focuses on key short-and medium-range deterministic and ensemble forecast technologies for complex terrain.By introducing a three-dimensional reference atmosphere and a predictor-corrector iterative algorithm into the regional model's dynamical framework,the team enhanced the spatial accuracy and temporal integration stability of the high-resolution regional model.The team also developed data assimilation techniques for dense surface automatic weather stations and high spatiotemporal resolution imagery from China's Fengyun satellites,improving the monitoring and application capability of unconventional observations for the Winter Olympics.Furthermore,they established a3 km high-resolution regional ensemble prediction system by advancing multiscale hybrid initial perturbation techniques and stochastic perturbation methods for physical processes with spatiotemporal correlations,suitable for complex terrain.To enhance deterministic and probabilistic forecasts at grid and station scales over complex terrain,the team studied bias correction techniques across different resolutions and developed methods for rapidly and effectively extracting key forecast information from large volumes of model output.In particular,machine learning-based approaches were employed to process and fuse massive forecast products containing probabilistic information.These efforts led to the development of a seamless Winter Olympics meteorological forecasting system covering a lead time of 0–15 days and the entire competition zone,featuring forecast updates every hour within 24 h,every 3 h within 24–72 h,and every 12 h within 72–360 h.These products were applied comprehensively in real-time operations during the winter training,test events,and the Olympic and Paralympic Games,representing the highest level of China's independently developed NWP systems in meteorological support for major events.The integrated technological achievements have since been incorporated into the national operational NWP system,and they continue to play a vital role in daily forecasting services,disaster prevention and mitigation,and support for major events.展开更多
Carbon nanogels(CNGs)with dual ability of reactive oxygen species(ROS)imaging and photodynamic therapy have been designed with selfassembled chemiluminescent carbonized polymer dots(CPDs).With efficient deep-red/near-...Carbon nanogels(CNGs)with dual ability of reactive oxygen species(ROS)imaging and photodynamic therapy have been designed with selfassembled chemiluminescent carbonized polymer dots(CPDs).With efficient deep-red/near-infrared chemiluminescence(CL)emission and distinctive photodynamic capacity,the H2O2-driven chemiluminescent CNGs are further designed by assembling the polymeric conjugate and CL donors,enabling an in vitro and in vivo ROS bioimaging capability in animal inflammation models and a high-performance therapy for xenograft tumors.Mechanistically,ROS generated in inflammatory sites or tumor microenvironment can trigger the chemically initiated electron exchange luminescence in the chemical reaction of peroxalate and H2O2,enabling in vivo CL imaging.Meanwhile,part of the excited-state electrons will transfer to the ambient H2O or dissolved oxygen and in turn lead to the type I and type II photochemical ROS production of hydroxyl radicals or singlet oxygen,endowing the apoptosis of tumor cells and thus enabling cancer therapy.These results open up a new avenue for the design of multifunctional nanomaterials for bioimaging and antienoplastic agents.展开更多
A novel slotted optical microdisk resonator, which significantly enhances light–matter interaction and provides a promising approach for increasing the sensitivity of sensors, is theoretically and numerically investi...A novel slotted optical microdisk resonator, which significantly enhances light–matter interaction and provides a promising approach for increasing the sensitivity of sensors, is theoretically and numerically investigated. In this slotted resonator, the mode splitting is generated due to reflection of the slot. Remarkably, effects of the slot width and angular position on the mode splitting are mainly studied. The results reveal that the mode splitting is a second function of the slot width, and the maximum mode splitting induced by the slot deformation is achieved with 2.7853 × 10~9Hz∕nm. Therefore, the slotted resonator is an excellent candidate for pressure and force sensing. Besides, the influence of the slot angular position on the mode splitting is a cosine curve with the highest sensitivity of 1.23 × 10^(11)Hz∕deg; thus, the optical characteristic demonstrates that the slotted resonator can be used for inertial measurements.展开更多
基金supported by the Scientific Research Project of China Three Gorges Corporation, China (No. 202003081)the National Key Research and Development Program of China (No. 2020YFC1908702)the National Natural Science Foundation of China (NSFC) (No. 52131002)。
文摘Sludge is the by-product of wastewater treatment process. Multisource sludge can be defined as sludge from different sources. Based on the sludge properties of five typical cities in the Yangtze River basin, including Jiujiang, Wuhu, Lu’an, Zhenjiang and Wuhan, this study investigated and summarized the characteristic variations and distribution differences of multiple indicators and substances from municipal sludge, dredged sludge, and river and lake sediments. The results demonstrated pH of multisource sludge was relatively stable in the neutral range. Organic matter and water content among municipal sludge were high and varied considerably between different wastewater treatment plants. Dredged sludge had an obviously higher sand content and wider particle distribution, which could be considered for graded utilization depending on its size. The nutrients composition of river and lake sediments was usually stable and special, with lower nitrogen and phosphorus content but higher potassium levels. The sources of heavy metals and persistent organic pollutants in multisource sludge were correlated, generally much higher among municipal sludge than dredged sludge and river and lake sediments, which were the most important limitation for final land utilization. Despite various properties of multisource sludge, the final fate and destination have some overall similarities, which need to be supplemented and improved by standards and laws. The study provided a preliminary analysis of suitable technical routes for municipal sludge, dredged sludge, river and lake sediments based on their different characteristics respectively, which was of great significance for multisource sludge co-treatment and disposal in the future of China.
基金supported by the National Science Foundation of China (Grant no. 51408419)the National Key Technology Research and Development Program of China (Grant nos. 2014BAL02B02-03 and 2014BAC29B01)the Key Program for International S&T Cooperation Projects of China (Grant no. 2012DFG91380)
文摘As an important intermediate product, short-chain fatty acids（SCFAs） can be generated after hydrolysis and acidification from waste activated sludge, and then can be transformed to methane during anaerobic digestion process. In order to obtain more SCFA and methane,most studies in literatures were centered on enhancing the hydrolysis of sludge anaerobic digestion which was proved as un-efficient. Though the alkaline pretreatment in our previous study increased both the hydrolysis and acidification processes, it had a vast chemical cost which was considered uneconomical. In this paper, a low energy consumption pretreatment method, i.e. enhanced the whole three stages of the anaerobic fermentation processes at the same time, was reported, by which hydrolysis and acidification were both enhanced, and the SCFA and methane generation can be significantly improved with a small quantity of chemical input. Firstly, the effect of different pretreated temperatures and pretreatment time on sludge hydrolyzation was compared. It was found that sludge pretreated at 100°C for 60 min can achieve the maximal hydrolyzation. Further, effects of different initial p Hs on acidification of the thermal pretreated sludge were investigated and the highest SCFA was observed at initial p H 9.0with fermentation time of 6 d, the production of which was 348.63 mg COD/g VSS（6.8 times higher than the blank test） and the acetic acid was dominant acid. Then, the mechanisms for this new pretreatment significantly improving SCFA production were discussed. Finally,the effect of this low energy consumption pretreatment on methane generation was investigated.
基金Guangzhou Huashang College 2022 Innovation and Entrepreneurship Education Research Project“Research on the Influencing Factors of College Students’Network Entrepreneurship Intention Based on TPB Model”(Project Number:HS2022CXCY04)。
文摘This year,the number college graduates in China surpassed tens of millions for the first time.The employment rate of fresh graduates has been concerning.In view of this,network entrepreneurship has become an important channel and platform to solve the problem of college students’employment.The government,society and universities has been actively encouraging college students'network entrepreneurship as the value of college students'network entrepreneurship is significant.This paper analyzes the current situation of college students'network entrepreneurship and the problems faced through the survey data and thus suggests corresponding countermeasures.
基金supported by the National Natural Science Foundation of China(NSFC)Major Program(Grant No.42090032)NSFC Projects(Grant Nos.42475169,42175012)the Science and Technology Winter Olympics Special Subject(Grant No.2018YFF0300103)。
文摘To meet the demands for seamless medium-and short-range weather forecasting during the Beijing Winter Olympics(2022),the Winter Olympics research team at the Earth System Modeling and Prediction Centre(CEMC)of the China Meteorological Administration(CMA)developed an integrated global and regional numerical weather prediction(NWP)model system.In support of the Winter Olympics,the system focuses on key short-and medium-range deterministic and ensemble forecast technologies for complex terrain.By introducing a three-dimensional reference atmosphere and a predictor-corrector iterative algorithm into the regional model's dynamical framework,the team enhanced the spatial accuracy and temporal integration stability of the high-resolution regional model.The team also developed data assimilation techniques for dense surface automatic weather stations and high spatiotemporal resolution imagery from China's Fengyun satellites,improving the monitoring and application capability of unconventional observations for the Winter Olympics.Furthermore,they established a3 km high-resolution regional ensemble prediction system by advancing multiscale hybrid initial perturbation techniques and stochastic perturbation methods for physical processes with spatiotemporal correlations,suitable for complex terrain.To enhance deterministic and probabilistic forecasts at grid and station scales over complex terrain,the team studied bias correction techniques across different resolutions and developed methods for rapidly and effectively extracting key forecast information from large volumes of model output.In particular,machine learning-based approaches were employed to process and fuse massive forecast products containing probabilistic information.These efforts led to the development of a seamless Winter Olympics meteorological forecasting system covering a lead time of 0–15 days and the entire competition zone,featuring forecast updates every hour within 24 h,every 3 h within 24–72 h,and every 12 h within 72–360 h.These products were applied comprehensively in real-time operations during the winter training,test events,and the Olympic and Paralympic Games,representing the highest level of China's independently developed NWP systems in meteorological support for major events.The integrated technological achievements have since been incorporated into the national operational NWP system,and they continue to play a vital role in daily forecasting services,disaster prevention and mitigation,and support for major events.
基金the National Natural Science Foundation of China(Nos.12074348,U2004168,U1904142,and U21A2070)the China Postdoctoral Science Foundation(No.2020M682310)+1 种基金the Natural Science Foundation of Henan Province(No.212300410078)Science and Technology Department of Henan Province(No.182102410010).
文摘Carbon nanogels(CNGs)with dual ability of reactive oxygen species(ROS)imaging and photodynamic therapy have been designed with selfassembled chemiluminescent carbonized polymer dots(CPDs).With efficient deep-red/near-infrared chemiluminescence(CL)emission and distinctive photodynamic capacity,the H2O2-driven chemiluminescent CNGs are further designed by assembling the polymeric conjugate and CL donors,enabling an in vitro and in vivo ROS bioimaging capability in animal inflammation models and a high-performance therapy for xenograft tumors.Mechanistically,ROS generated in inflammatory sites or tumor microenvironment can trigger the chemically initiated electron exchange luminescence in the chemical reaction of peroxalate and H2O2,enabling in vivo CL imaging.Meanwhile,part of the excited-state electrons will transfer to the ambient H2O or dissolved oxygen and in turn lead to the type I and type II photochemical ROS production of hydroxyl radicals or singlet oxygen,endowing the apoptosis of tumor cells and thus enabling cancer therapy.These results open up a new avenue for the design of multifunctional nanomaterials for bioimaging and antienoplastic agents.
基金National Natural Science Foundation of China(NSFC)(61575014)Natural Science Foundation of Beijing Municipality(4162038)
文摘A novel slotted optical microdisk resonator, which significantly enhances light–matter interaction and provides a promising approach for increasing the sensitivity of sensors, is theoretically and numerically investigated. In this slotted resonator, the mode splitting is generated due to reflection of the slot. Remarkably, effects of the slot width and angular position on the mode splitting are mainly studied. The results reveal that the mode splitting is a second function of the slot width, and the maximum mode splitting induced by the slot deformation is achieved with 2.7853 × 10~9Hz∕nm. Therefore, the slotted resonator is an excellent candidate for pressure and force sensing. Besides, the influence of the slot angular position on the mode splitting is a cosine curve with the highest sensitivity of 1.23 × 10^(11)Hz∕deg; thus, the optical characteristic demonstrates that the slotted resonator can be used for inertial measurements.
