Backlund transformation, exact solitary wave solutions, nonlinear supperposi tion formulae and infinite conserved laws are presented by using TU-pattern. The algorithm involves wide applications for nonlinear evolutio...Backlund transformation, exact solitary wave solutions, nonlinear supperposi tion formulae and infinite conserved laws are presented by using TU-pattern. The algorithm involves wide applications for nonlinear evolution equations.展开更多
his paper deals with the phase trans formation of austenite to ferrite within the critical temperature region(between Ac1 and Ac3).The results show that the volume fraction of trans formation of ferrite formed isother...his paper deals with the phase trans formation of austenite to ferrite within the critical temperature region(between Ac1 and Ac3).The results show that the volume fraction of trans formation of ferrite formed isothermally from austenite is mainly varied with the austenitizing temperature.The higher the austenitizing temperature,the more volume fraction of the ferrite formed isothermally from austenite.Besides,the phase trans formation of austenite to ferrite within the critical temperature region was checked by austenitizing isothermal time.The volume fraction of ferrite formed isothermally from austenite within the critical temperature region for different isothermal time has heen examined experimen tally.The lglg(l-fv)-1 vs lgt relation does not follow the Avrami equation strictly and consists of two straight lines.展开更多
In this paper, an in situ metallographic video system was used to study the morphology in Cu-Zn-Al shape memory alloy (SMA) during thermal cycling phase tmnsforma-tion. There are seven different types of martensite mo...In this paper, an in situ metallographic video system was used to study the morphology in Cu-Zn-Al shape memory alloy (SMA) during thermal cycling phase tmnsforma-tion. There are seven different types of martensite morphology in Cu-Zn-Al SMA,i.e. plate, spean bamboo, noose, round-spot, line and dot-like martensites. During transformation and inverse-transformation, the thermoelastic martensites were rising and falling, growing and shrinking, splitting and merping. The growth patterns of thermoelastic martensite were divided into three types: fast growing, very slow ex-pansion and uniform automatic growth. Automatic growth appeared when ageing at a temperature below Ms. The result, for the first time, coofirmed Olson and Cohen,s suggestion that thermoelastic martensite may be automatically grown when ageing be-low Ms. With increasing numbers of thermal cycling, both the memory recovery ratio (% )and memory recoverp degradation (%) degraded logarithmically. The degrada-tion was steep in the initial stage and then became more and more gradual in the middle and the final stages caused by the stabilisation of martensite. In the initial stage, vacancies assumed the controlling role, while dislocations took the major role in other stages. The martensite transformation caused the intedeces to become bent and blurmd, but with increasing cycling numbers, the movements of interface had the same degradation effects as the memory recovery ratio curves. Under these conditions, we also found the martensites on one side of the intedece became reorientated and par-allel to the intedece. It was therefore concluded that the movement degradation of the interface and the appearance of bamboo like martensite induced the degradation of two way shape memory effect (TWMP).展开更多
In recent years, with the development of terrestrial sequence stratigraphy, more attention has been focused on the study of the terrestrial lacustrine sequence stratigraphic model globally. Different viewpoints are pr...In recent years, with the development of terrestrial sequence stratigraphy, more attention has been focused on the study of the terrestrial lacustrine sequence stratigraphic model globally. Different viewpoints are preferred by researchers. Under the guidance of the theory of sequence stratigraphy, the findings of this paper indicate that climate is a major factor controlling the formation of the fourth-order sequence, based upon the study of the sequence stratigraphy in the Green River Formation of the Uinta basin in the USA. It also divides the fourth-order sequence in the terrestrial lacustrine basin into two system tracts: the wet (rising) half-cycle and the dry (falling) half- cycle, establishing a new-style fourth-order sequence stratigraphic model for the terrestrial lacustrine basin, that is, the climate-genetic sequence stratigraphic model. As a result, the theory of sequence stratigraphy is greatly enriched.展开更多
The middle Jurassic Zhiluo Formation in the Dongsheng is comprised of a big set of green sandstone/mudstone with most of uranium orebodies occurring in close proximity to its footwall.By synthesizing field observation...The middle Jurassic Zhiluo Formation in the Dongsheng is comprised of a big set of green sandstone/mudstone with most of uranium orebodies occurring in close proximity to its footwall.By synthesizing field observations,region analysis,data collected from previous coal and uranium borehole,a regional north-south geological profile across the entire orefield is conducted.Experiments on sandstone/mudstone including rock mineral identification,clastic micromorphology and element geochemistry were carried out.Information from the geological profile indicates that green sandstone/mudstone is widely present in a stable horizon with clear boundaries to the country rock.Microscopic observations and geochemical data on sandstone/mudstone exhibit similar mineral composition with almost identical slightly flat,minor Eu enriched,Ce depleted chondrite-normalized REE patterns.Furthermore,the green clay membrane of the clasts has a complex composition containing chlorite/smectite,green smectite,chlorite,and green kaolinite,with elements including Fe,Mg,Si,and Al.These above results indicate that the green sandstone/mudstone underwent resemble sedimentary diagenetic processes as the country rock without transformation by large-scale regional fluid,while the existence of Fe2+-rich membrane is the main factor to the green sandstone/mudstone.Further concentration of the pre-enrichment uranium during diagenetic process led to the final formation for uranium deposits.The above studies are conducive to enrich the metallogenic mechanism of sandstone type uranium deposits and could provide certain reference for uranium exploration and deployment.展开更多
Direct electrochemical formation of hydrogen peroxide(H2O2) from pure O2 and H2on cheap metal-free earth abundant catalysts has emerged as the highest atom-efficient and environmentally friendly reaction pathway and...Direct electrochemical formation of hydrogen peroxide(H2O2) from pure O2 and H2on cheap metal-free earth abundant catalysts has emerged as the highest atom-efficient and environmentally friendly reaction pathway and is therefore of great interest from an academic and industrial point of view. Very recently,novel metal-free mesoporous nitrogen-doped carbon catalysts have attracted large attention due to the unique reactivity and selectivity for the electrochemical hydrogen peroxide formation [1–3]. In this work,we provide deeper insights into the electrocatalytic activity, selectivity and durability of novel metal-free mesoporous nitrogen-doped carbon catalyst for the peroxide formation with a particular emphasis on the influence of experimental reaction parameters such as p H value and electrode potential for three different electrolytes. We used two independent approaches for the investigation of electrochemical hydrogen peroxide formation, namely rotating ring-disk electrode(RRDE) technique and photometric UV–VIS technique. Our electrochemical and photometric results clearly revealed a considerable peroxide formation activity as well as high catalyst durability for the metal-free nitrogen-doped carbon catalyst material in both acidic as well as neutral medium at the same electrode potential under ambient temperature and pressure. In addition, the obtained electrochemical reactivity and selectivity indicate that the mechanisms for the electrochemical formation and decomposition of peroxide are strongly dependent on the p H value and electrode potential.展开更多
High speed milling experiments using nitrogen-oil-mist as the cutting medium were carried out to investigate the characteristics of chip formation for Ti-6Al-4V alloy.Within the range of conditions employed(cutting sp...High speed milling experiments using nitrogen-oil-mist as the cutting medium were carried out to investigate the characteristics of chip formation for Ti-6Al-4V alloy.Within the range of conditions employed(cutting speed,vc=190-300 m/min;cutting depth of axial,ap=5,7 mm),saw-tooth chips were produced in these experiments.During the macro and micro analysis of the Ti-6Al-4V chips,an optical microscope and a scanning electron microscope(SEM)were used to study the microstructure and the morphology of the chips,and the X-ray photoelectron spectroscopy(XPS)was employed for chemical analysis.Comparisons were made to study the influence of different cutting media(nitrogen-oil-mist,air-oil-mist and dry cutting condition)on chip formation.Results indicate that cutting media have significant effects on chip formation.Nitrogen-oil-mist is more suitable for improving the contact condition at chip-tool interface and increasing the tool life in high speed milling of Ti-6Al-4V alloy than air-oil-mist and dry cutting.展开更多
Larger amount of austenite could be retained in an intercritically heat-treated bainite- transformed steel. The elongation and the strength-ductility balance of the steel could be enhanced considerably due to strain-i...Larger amount of austenite could be retained in an intercritically heat-treated bainite- transformed steel. The elongation and the strength-ductility balance of the steel could be enhanced considerably due to strain-induced martensite transformation and transformation- induced plasticity (TRIP) of retained austenite. The effects of test temperature and strain rate on the mechanical properties and strain induced transformation behavior of retained austenite in the steel were investigated. Total elongation and strength-ductility balance of the specimen reached maximum when it strained at a strain rate of 2.8×10-4s-1 and at 350℃. The relation between test temperature and tensile properties showed the same tendency at three kinds of strain rates. Flow stress increased considerably with decreasing the strain rate.展开更多
Vietnam's economy is developing more and more rapidly, people's income are increasing, and the living condition is better. Today, consumer are increasingly aware of the quality of products, especially fresh food, bu...Vietnam's economy is developing more and more rapidly, people's income are increasing, and the living condition is better. Today, consumer are increasingly aware of the quality of products, especially fresh food, but they have a little opportunity to choose the products which satisfy the needs, because they are limited to the product information and product origin. Fresh vegetables are one of the essential foods in the family living. The selection of fresh vegetables is not only to serve the basic needs as eating and drinking, but also to include the need for safety. Currently, consumer demand for fresh vegetable are great, especially when the living standards are becoming higher and people pay more attention to their health, especially for the consumer of Ho Chi Minh City. How fresh is vegetable market in Ho Chi Minh City today like.'? What is consumers' awareness of fresh vegetable? What factors impact the fresh vegetable buying behavior of consumers? Why does the development of fresh vegetable market in Ho Chi Minh City currently face many difficulties? This study surveys the research, analyzes the factors affecting the economic area formation of fresh vegetable plantation at suburb of rio Chi Minh City.展开更多
The Mesozoic and Cenozoic strata in the Junggar basin developed two sets of shallow to semi-deep lacustrine shale, namely, the Cretaceous Qingshuihe Formation (K_(1q)) and the Paleogene Anjihaihe Formation (E_(2-3a))....The Mesozoic and Cenozoic strata in the Junggar basin developed two sets of shallow to semi-deep lacustrine shale, namely, the Cretaceous Qingshuihe Formation (K_(1q)) and the Paleogene Anjihaihe Formation (E_(2-3a)). Through organic petrology and scanning electron microscope (SEM) observation, it is found that the primary hydrocarbon-generating organic matter (OM) in the two sets of strata is different. The biological precursor of the E_(2-3a) OM is mainly green algae (Pediastrum), while the precursor of K_(1q) kerogen is mainly cyanobacteria (Oscillatoria). Then, the E_(2-3a) green algae-rich shale and K_(1q) cyanobacteria-rich shale were subjected to hydrous pyrolysis and kinetic analysis, respectively. The results show that the evolution modes of hydrocarbon generation of the typical shales are very different. Green algae have the characteristics of a low oil generation threshold, heavy oil quality, and no prominent oil peak, while cyanobacteria have the characteristics of late oil generation, concentrated hydrocarbon generation, and relatively light oil quality. The characteristics of oil generation can also be well reflected in the composition evolution of the crude oil components. The carbon isotope of gas, kerogen, and extracts of the E_(2-3a) green algae-rich shale are significantly heavier than the K_(1q) cyanobacteria-rich shale, which may be related to the living habits of their biological precursors, carbon source usage, photosynthesis efficiency, and carbon fixation efficiency.展开更多
The continuous input of various emerging contaminants(ECs)has inevitably introduced large amounts of transformation products(TPs)in natural and engineering water scenarios.Structurally similar to the precursor species...The continuous input of various emerging contaminants(ECs)has inevitably introduced large amounts of transformation products(TPs)in natural and engineering water scenarios.Structurally similar to the precursor species,the TPs are expected to possess comparative,if not more serious,environmental properties and risks.This review summarizes the state-of-the-art knowledge regarding the integrated risk assessment frameworks of TPs of ECs,mainly involving the exposure-and effectdriven analysis.The inadequate information within existing frameworks that was essential and critical for developing a better risk assessment framework was discussed.The main strategic improvements include(1)non-targeted product analysis in both laboratory and field samples,(2)omics-based highthroughput toxicity assessment,(3)multichannel-driven mode of action in conjugation with effectdirected analysis,and(4)machine learning technology.Overall,this review provides a concise but comprehensive insight into the optimized strategy for evaluating the environmental risks and screening the key toxic products from the cocktail mixtures of ECs and their TPs in the global water cycle.This facilitates deciphering the mode of toxicity in complex chemical mixtures and prioritizing the regulated TPs among the unknown products,which have the potential to be considered a class of novel"ECs"ofgreatconcern.展开更多
This study evaluates the effects of green manure, inorganic fertilizers and their combinations on the growth and yield of soybeans in the Mount Cameroon Region. The experiment involved 10 treatments which include, 5 M...This study evaluates the effects of green manure, inorganic fertilizers and their combinations on the growth and yield of soybeans in the Mount Cameroon Region. The experiment involved 10 treatments which include, 5 Mg/ha green manure, 180 Kg P/ha triple superphosphate fertilizer (P), 180 Kg/ha NPK (20:10:10), 2 Mg/ha green manure + 90 kg P/ha, 3 Mg/ha green manure + 90 kg P/ha, 5 Mg/ha green manure + 90 Kg P, 2 Mg/ha green manure + 90 kg NPK/ha, 3 Mg/ha green manure + 90 kg NPK/ha, 5 Mg/ha green manure + 90 kg NPK and a control. Plant growth characters were assessed every 14 days for a period of 70 days for the late (August) and early (March) planting seasons. The results indicated that plants supplied with 5 Mg/ha green manure had the highest plant heights of 60.7 cm, and this was significantly different from the control which had the least height (52.76 cm). Stem collar diameter was significantly (p 0.001) increased with treatments in both seasons. Plants supplied with 5 Mg/ha green manure recorded the highest stover yield (10.59 Mg/ha), and this was significantly different from the control which had the least (6.64 Mg/ha). Plants supplied with 5 Mg/ha green manure had the highest days to flowering (38 days), while plants supplied with 5 Mg/ha green manure + 90 Kg NPK had the least (33 days) which was significantly different (p 0.01). The highest number of pods per plant was observed in plants supplied with 5 Mg/ha green manure (57 pods per plants), which was significantly different from the control (39 pods per plant). Plants supplied with 5 Mg/ha green manure + 90 Kg NPK recorded the highest grain yield (4.97 Mg ha<sup>-1</sup>), while the lowest grain yield was observed in the control (2.22 Mg ha<sup>-1</sup>). Results from this study can be used by soybeans farmers in the Mount Cameroon region to enhance productivity of this crop and thereby improving their living standards and food security in Cameroon.展开更多
文摘Backlund transformation, exact solitary wave solutions, nonlinear supperposi tion formulae and infinite conserved laws are presented by using TU-pattern. The algorithm involves wide applications for nonlinear evolution equations.
文摘his paper deals with the phase trans formation of austenite to ferrite within the critical temperature region(between Ac1 and Ac3).The results show that the volume fraction of trans formation of ferrite formed isothermally from austenite is mainly varied with the austenitizing temperature.The higher the austenitizing temperature,the more volume fraction of the ferrite formed isothermally from austenite.Besides,the phase trans formation of austenite to ferrite within the critical temperature region was checked by austenitizing isothermal time.The volume fraction of ferrite formed isothermally from austenite within the critical temperature region for different isothermal time has heen examined experimen tally.The lglg(l-fv)-1 vs lgt relation does not follow the Avrami equation strictly and consists of two straight lines.
文摘In this paper, an in situ metallographic video system was used to study the morphology in Cu-Zn-Al shape memory alloy (SMA) during thermal cycling phase tmnsforma-tion. There are seven different types of martensite morphology in Cu-Zn-Al SMA,i.e. plate, spean bamboo, noose, round-spot, line and dot-like martensites. During transformation and inverse-transformation, the thermoelastic martensites were rising and falling, growing and shrinking, splitting and merping. The growth patterns of thermoelastic martensite were divided into three types: fast growing, very slow ex-pansion and uniform automatic growth. Automatic growth appeared when ageing at a temperature below Ms. The result, for the first time, coofirmed Olson and Cohen,s suggestion that thermoelastic martensite may be automatically grown when ageing be-low Ms. With increasing numbers of thermal cycling, both the memory recovery ratio (% )and memory recoverp degradation (%) degraded logarithmically. The degrada-tion was steep in the initial stage and then became more and more gradual in the middle and the final stages caused by the stabilisation of martensite. In the initial stage, vacancies assumed the controlling role, while dislocations took the major role in other stages. The martensite transformation caused the intedeces to become bent and blurmd, but with increasing cycling numbers, the movements of interface had the same degradation effects as the memory recovery ratio curves. Under these conditions, we also found the martensites on one side of the intedece became reorientated and par-allel to the intedece. It was therefore concluded that the movement degradation of the interface and the appearance of bamboo like martensite induced the degradation of two way shape memory effect (TWMP).
基金These research results are part of a key international cooperation project carried out during 2003 and 2005 and financially supported by SINOPEC.
文摘In recent years, with the development of terrestrial sequence stratigraphy, more attention has been focused on the study of the terrestrial lacustrine sequence stratigraphic model globally. Different viewpoints are preferred by researchers. Under the guidance of the theory of sequence stratigraphy, the findings of this paper indicate that climate is a major factor controlling the formation of the fourth-order sequence, based upon the study of the sequence stratigraphy in the Green River Formation of the Uinta basin in the USA. It also divides the fourth-order sequence in the terrestrial lacustrine basin into two system tracts: the wet (rising) half-cycle and the dry (falling) half- cycle, establishing a new-style fourth-order sequence stratigraphic model for the terrestrial lacustrine basin, that is, the climate-genetic sequence stratigraphic model. As a result, the theory of sequence stratigraphy is greatly enriched.
基金This work was financially and technically supported by National Key Basic Research Program(2015CB453000)of Ministry Science and TechnologyGeological Survey Projects(DD20160127 and DD20160128)from China Geological Surveythe International Geoscience Program(IGCP675)from UNESCO.
文摘The middle Jurassic Zhiluo Formation in the Dongsheng is comprised of a big set of green sandstone/mudstone with most of uranium orebodies occurring in close proximity to its footwall.By synthesizing field observations,region analysis,data collected from previous coal and uranium borehole,a regional north-south geological profile across the entire orefield is conducted.Experiments on sandstone/mudstone including rock mineral identification,clastic micromorphology and element geochemistry were carried out.Information from the geological profile indicates that green sandstone/mudstone is widely present in a stable horizon with clear boundaries to the country rock.Microscopic observations and geochemical data on sandstone/mudstone exhibit similar mineral composition with almost identical slightly flat,minor Eu enriched,Ce depleted chondrite-normalized REE patterns.Furthermore,the green clay membrane of the clasts has a complex composition containing chlorite/smectite,green smectite,chlorite,and green kaolinite,with elements including Fe,Mg,Si,and Al.These above results indicate that the green sandstone/mudstone underwent resemble sedimentary diagenetic processes as the country rock without transformation by large-scale regional fluid,while the existence of Fe2+-rich membrane is the main factor to the green sandstone/mudstone.Further concentration of the pre-enrichment uranium during diagenetic process led to the final formation for uranium deposits.The above studies are conducive to enrich the metallogenic mechanism of sandstone type uranium deposits and could provide certain reference for uranium exploration and deployment.
基金supported by the Technische Universitat Berlin,the Max Planck Society and the Cluster of Excellence“Unifying Concepts in Catalysis(Uni Cat)”
文摘Direct electrochemical formation of hydrogen peroxide(H2O2) from pure O2 and H2on cheap metal-free earth abundant catalysts has emerged as the highest atom-efficient and environmentally friendly reaction pathway and is therefore of great interest from an academic and industrial point of view. Very recently,novel metal-free mesoporous nitrogen-doped carbon catalysts have attracted large attention due to the unique reactivity and selectivity for the electrochemical hydrogen peroxide formation [1–3]. In this work,we provide deeper insights into the electrocatalytic activity, selectivity and durability of novel metal-free mesoporous nitrogen-doped carbon catalyst for the peroxide formation with a particular emphasis on the influence of experimental reaction parameters such as p H value and electrode potential for three different electrolytes. We used two independent approaches for the investigation of electrochemical hydrogen peroxide formation, namely rotating ring-disk electrode(RRDE) technique and photometric UV–VIS technique. Our electrochemical and photometric results clearly revealed a considerable peroxide formation activity as well as high catalyst durability for the metal-free nitrogen-doped carbon catalyst material in both acidic as well as neutral medium at the same electrode potential under ambient temperature and pressure. In addition, the obtained electrochemical reactivity and selectivity indicate that the mechanisms for the electrochemical formation and decomposition of peroxide are strongly dependent on the p H value and electrode potential.
基金the National Natural Science Foundation of China (Grant No. 50175051)
文摘High speed milling experiments using nitrogen-oil-mist as the cutting medium were carried out to investigate the characteristics of chip formation for Ti-6Al-4V alloy.Within the range of conditions employed(cutting speed,vc=190-300 m/min;cutting depth of axial,ap=5,7 mm),saw-tooth chips were produced in these experiments.During the macro and micro analysis of the Ti-6Al-4V chips,an optical microscope and a scanning electron microscope(SEM)were used to study the microstructure and the morphology of the chips,and the X-ray photoelectron spectroscopy(XPS)was employed for chemical analysis.Comparisons were made to study the influence of different cutting media(nitrogen-oil-mist,air-oil-mist and dry cutting condition)on chip formation.Results indicate that cutting media have significant effects on chip formation.Nitrogen-oil-mist is more suitable for improving the contact condition at chip-tool interface and increasing the tool life in high speed milling of Ti-6Al-4V alloy than air-oil-mist and dry cutting.
基金the National Natural Science Foundation of China(No.50334010)the Doctor Degree Thesis Subsidization Item of Northeastern Universiry(No.200302).
文摘Larger amount of austenite could be retained in an intercritically heat-treated bainite- transformed steel. The elongation and the strength-ductility balance of the steel could be enhanced considerably due to strain-induced martensite transformation and transformation- induced plasticity (TRIP) of retained austenite. The effects of test temperature and strain rate on the mechanical properties and strain induced transformation behavior of retained austenite in the steel were investigated. Total elongation and strength-ductility balance of the specimen reached maximum when it strained at a strain rate of 2.8×10-4s-1 and at 350℃. The relation between test temperature and tensile properties showed the same tendency at three kinds of strain rates. Flow stress increased considerably with decreasing the strain rate.
文摘Vietnam's economy is developing more and more rapidly, people's income are increasing, and the living condition is better. Today, consumer are increasingly aware of the quality of products, especially fresh food, but they have a little opportunity to choose the products which satisfy the needs, because they are limited to the product information and product origin. Fresh vegetables are one of the essential foods in the family living. The selection of fresh vegetables is not only to serve the basic needs as eating and drinking, but also to include the need for safety. Currently, consumer demand for fresh vegetable are great, especially when the living standards are becoming higher and people pay more attention to their health, especially for the consumer of Ho Chi Minh City. How fresh is vegetable market in Ho Chi Minh City today like.'? What is consumers' awareness of fresh vegetable? What factors impact the fresh vegetable buying behavior of consumers? Why does the development of fresh vegetable market in Ho Chi Minh City currently face many difficulties? This study surveys the research, analyzes the factors affecting the economic area formation of fresh vegetable plantation at suburb of rio Chi Minh City.
基金supported by Xinjiang Oilfield Company of China(No.2020-C4006).
文摘The Mesozoic and Cenozoic strata in the Junggar basin developed two sets of shallow to semi-deep lacustrine shale, namely, the Cretaceous Qingshuihe Formation (K_(1q)) and the Paleogene Anjihaihe Formation (E_(2-3a)). Through organic petrology and scanning electron microscope (SEM) observation, it is found that the primary hydrocarbon-generating organic matter (OM) in the two sets of strata is different. The biological precursor of the E_(2-3a) OM is mainly green algae (Pediastrum), while the precursor of K_(1q) kerogen is mainly cyanobacteria (Oscillatoria). Then, the E_(2-3a) green algae-rich shale and K_(1q) cyanobacteria-rich shale were subjected to hydrous pyrolysis and kinetic analysis, respectively. The results show that the evolution modes of hydrocarbon generation of the typical shales are very different. Green algae have the characteristics of a low oil generation threshold, heavy oil quality, and no prominent oil peak, while cyanobacteria have the characteristics of late oil generation, concentrated hydrocarbon generation, and relatively light oil quality. The characteristics of oil generation can also be well reflected in the composition evolution of the crude oil components. The carbon isotope of gas, kerogen, and extracts of the E_(2-3a) green algae-rich shale are significantly heavier than the K_(1q) cyanobacteria-rich shale, which may be related to the living habits of their biological precursors, carbon source usage, photosynthesis efficiency, and carbon fixation efficiency.
基金the Natural Science Foundation of China-Joint Fund Project(No.U2005206)the Xiamen Municipal Bureau of Science and Technology(No.YDZX20203502000003)the support of the President Research Funds from Xiamen University(No.20720210081).
文摘The continuous input of various emerging contaminants(ECs)has inevitably introduced large amounts of transformation products(TPs)in natural and engineering water scenarios.Structurally similar to the precursor species,the TPs are expected to possess comparative,if not more serious,environmental properties and risks.This review summarizes the state-of-the-art knowledge regarding the integrated risk assessment frameworks of TPs of ECs,mainly involving the exposure-and effectdriven analysis.The inadequate information within existing frameworks that was essential and critical for developing a better risk assessment framework was discussed.The main strategic improvements include(1)non-targeted product analysis in both laboratory and field samples,(2)omics-based highthroughput toxicity assessment,(3)multichannel-driven mode of action in conjugation with effectdirected analysis,and(4)machine learning technology.Overall,this review provides a concise but comprehensive insight into the optimized strategy for evaluating the environmental risks and screening the key toxic products from the cocktail mixtures of ECs and their TPs in the global water cycle.This facilitates deciphering the mode of toxicity in complex chemical mixtures and prioritizing the regulated TPs among the unknown products,which have the potential to be considered a class of novel"ECs"ofgreatconcern.
文摘This study evaluates the effects of green manure, inorganic fertilizers and their combinations on the growth and yield of soybeans in the Mount Cameroon Region. The experiment involved 10 treatments which include, 5 Mg/ha green manure, 180 Kg P/ha triple superphosphate fertilizer (P), 180 Kg/ha NPK (20:10:10), 2 Mg/ha green manure + 90 kg P/ha, 3 Mg/ha green manure + 90 kg P/ha, 5 Mg/ha green manure + 90 Kg P, 2 Mg/ha green manure + 90 kg NPK/ha, 3 Mg/ha green manure + 90 kg NPK/ha, 5 Mg/ha green manure + 90 kg NPK and a control. Plant growth characters were assessed every 14 days for a period of 70 days for the late (August) and early (March) planting seasons. The results indicated that plants supplied with 5 Mg/ha green manure had the highest plant heights of 60.7 cm, and this was significantly different from the control which had the least height (52.76 cm). Stem collar diameter was significantly (p 0.001) increased with treatments in both seasons. Plants supplied with 5 Mg/ha green manure recorded the highest stover yield (10.59 Mg/ha), and this was significantly different from the control which had the least (6.64 Mg/ha). Plants supplied with 5 Mg/ha green manure had the highest days to flowering (38 days), while plants supplied with 5 Mg/ha green manure + 90 Kg NPK had the least (33 days) which was significantly different (p 0.01). The highest number of pods per plant was observed in plants supplied with 5 Mg/ha green manure (57 pods per plants), which was significantly different from the control (39 pods per plant). Plants supplied with 5 Mg/ha green manure + 90 Kg NPK recorded the highest grain yield (4.97 Mg ha<sup>-1</sup>), while the lowest grain yield was observed in the control (2.22 Mg ha<sup>-1</sup>). Results from this study can be used by soybeans farmers in the Mount Cameroon region to enhance productivity of this crop and thereby improving their living standards and food security in Cameroon.