The study, conducted at the Research Farm of the College of Agriculture, University of Tabriz in 2021, focused on the effects of various nitrogen-fixing bacterial isolates, biofertilizers containing nitrogen and phosp...The study, conducted at the Research Farm of the College of Agriculture, University of Tabriz in 2021, focused on the effects of various nitrogen-fixing bacterial isolates, biofertilizers containing nitrogen and phosphorus, as well as iron and zinc foliar applications on mustard growth under rainfed conditions. The results indicated that biofertilizers, whether used alone or in combination with chemical fertilizers, produced comparable grain and oil outputs compared to chemical fertilizers alone. Additionally, the application of iron and zinc through foliar spraying significantly enhanced both grain and oil production. These findings suggest that integrating nitrogen-fixing bacteria and biofertilizers could reduce reliance on chemical nitrogenous fertilizers, leading to decreased production expenses, improved product quality, and minimized environmental impact. This study highlights the potential for sustainable agricultural practices in dry land farming as a viable alternative to traditional chemical-intensive methods. Substituting chemical nitrogenous fertilizers with nitrogen-fixing bacteria or biofertilizers could result in cost savings in mustard grain and oil production while promoting environmental sustainability.展开更多
To study the influence of the pantograph fixing position on aerodynamic characteristics of high-speed trains, the aerodynamic models of high-speed trains with eight cars were established based on the theory of com- pu...To study the influence of the pantograph fixing position on aerodynamic characteristics of high-speed trains, the aerodynamic models of high-speed trains with eight cars were established based on the theory of com- putational fluid dynamics, and eight cases with pantographs fixed on different positions and in different operational orientations were considered. The pantographs were fixed on the front or the rear end of the first middle car or fixed on the front or the rear end of the last middle car. The external flow fields of the high-speed trains were numeri- cally simulated using the software STAR-CCM＋. The results show that the pantograph fixing position has little effect on the aerodynamic drag force of the head car and has a large effect on the aerodynamic drag force of the tail car. The influences of the pantograph fixing position on the aerodynamic lift forces of the head car, tail car and pan- tographs are obvious. Among the eight cases, considering the total aerodynamic drag force of the train and the aerodynamic lift force of the lifted pantograph, when the pantographs are fixed on the rear end of the last middle car and the lifted pantograph is in the knuckle-upstream ori- entation, the aerodynamic performance of the high-speed train is the best.展开更多
The universality of improved CO2 fixing upon the addition of mixed electron donors（MEDs）composed of Na2 S,NO2-,and S2O32-to non-photosynthetic microbial communities（NPMCs）obtained from 12 locations in four oceans ...The universality of improved CO2 fixing upon the addition of mixed electron donors（MEDs）composed of Na2 S,NO2-,and S2O32-to non-photosynthetic microbial communities（NPMCs）obtained from 12 locations in four oceans of the world was validated. The CO2 fixing efficiencies of NPMCs were universally enhanced by MED compared with those obtained using H2 alone as electron donor,with average increase of about 276%. An increase in microbial inoculation concentration could increase the net amount of CO2 fixing to853.34 mg/L in the presence of MED. NO2-and S2O32-may play the roles of both electron acceptor and electron donor under aerobic conditions,which may improve the energy utilization efficiency of NPMC and enhance the CO2 fixation efficiency. The sequence determination of 16 S ribosomal deoxyribonucleic acid（rDNA） from 150 bacteria of NPMC showed that more than 50% of the bacteria were symbiotic and there were many heterotrophic bacteria such as Vibrio natriegens. These results indicate that NPMC acts as a symbiotic CO2 fixing system. The interaction between autotrophic and heterotrophic bacteria may be a crucial factor supporting ladder utilization and recycling of energy/carbon source.展开更多
Mangrove provides a unique ecological niche to different microbes which play various roles in nutrient recycling as well as various environmental activities. The highly productive and diverse microbial community livin...Mangrove provides a unique ecological niche to different microbes which play various roles in nutrient recycling as well as various environmental activities. The highly productive and diverse microbial community living in mangrove ecosystems continuously transforms dead vegetation and recycle nitrogen, phosphorus, sulphur and other nutrients that can later be used by the plants. Mangrove ecosystems are rich in organic matter, and however, in general, they are nutrient-deficient ecosystems, especially of nitrogen and phosphorus. The present study investigated depth wise variation of Nitrifying bacteria, Nitrogen fixing bacteria, total bacterial population along with nitrate-nitrogen, nitrite-nitrogen and other physicochemical parameters of soil during pre-monsoon, monsoon and post-monsoon periods at three different sampling stations of mangrove sediments viz. deep forest region, rooted region and unrooted region. The microbial population was also found maximum in the deep forest sediment relative to the other two sites. Populations of cultureable microbes were found maximum in surface soil and decreased with increase in depth in Sundarban mangrove environment. A decreasing trend of total microbial load, nitrifying and nitrogen fixing bacteria with increase in depth were recorded throughout the year. Present study revealed the relationship among depth integrated variations of physicochemical components (viz. soil temperature, pH, salinity, nitrite nitrogen and nitrate nitrogen concentration) and total microbial load, nitrifying and nitrogen fixing bacteria microbial populations.展开更多
As special cylindrical briquettes of coal for long distance pipeline transportation and directly cleaned combustion the cleaned coal logs should possess two characteristics of transportation in pipeline and cleaned co...As special cylindrical briquettes of coal for long distance pipeline transportation and directly cleaned combustion the cleaned coal logs should possess two characteristics of transportation in pipeline and cleaned combustion. In order to make cleaned coal logs a rational technology for manufacturing, cleaned coal logs was designed and compound sulfur fixing binders with high effects of binding and sulfur-fixing was selected and combined. In addition, by means of characteristic experiments of strength, wear, waterproof and sulfur-fixing five different cleaned coal logs made with different compound sulfur fixing binders in different compaction conditions was tested and measured. Experimental results indicated that the manufacturing technology of cleaned coal logs was reasonable and the combination of compound sulfur fixing binders was scientific. Cleaned coal logs made up with the fourth group of coal mixture had high strength, good waterproof property, efficient sulfur-fixing, good characteristic of transportation, and achieved the performance requirement for pipeline transportation and sulfur fixing.展开更多
There are two connection modes between escalator step and step drive chain of outer roller,connector type A and type B.Connector type B after a period of running was found that the fixing bolt on the connector has loo...There are two connection modes between escalator step and step drive chain of outer roller,connector type A and type B.Connector type B after a period of running was found that the fixing bolt on the connector has loosened,which causes safety risks.In order to eliminate this security issue,the finite element modeling is proposed to analyze the relationship between the force generated by the connector type A or type B during the step band running and the assembly clearance or the assembly mode.So as to find out the root cause of fixing bolt loosening phenomenon,by redesigning the assembly clearance between the connector shaft and the chain hole,the fixing bolt of the connector is prevented from loosening during the step band running,ensuring the safe operation of escalators to avoid injury accidents.展开更多
There has always been a great need for simple and accurate bioassays for evaluating nutrient limitation in aquatic ecosystems. Whereas organic carbon is usually considered to be the limiting nutrient for microbial gro...There has always been a great need for simple and accurate bioassays for evaluating nutrient limitation in aquatic ecosystems. Whereas organic carbon is usually considered to be the limiting nutrient for microbial growth in many aquatic ecosystems, there are, however, many water sources that are limited by phosphorus or nitrogen. A method named ＂nitrogen fixing bacterial growth potential＂ （NFBGP） test, which is based on pre-culturing of autochthonous （target） microorganisms was described. The method was applied to evaluate phosphorus or nitrogen nutrient limitation in lake and sewage water samples using an isolate of the nitrogen fixing bacterium, Azorhizobium sp. WS6. The results corresponded well to those from the traditional algal growth potential （AGP） test and the bacterial regrowth potential （BRP） test, suggesting that the NFBGP test is a useful supplementary method for evaluating the limiting nutrient, especially phosphorus, in an aquatic environment.展开更多
Growing in the medium containing 0.10 mol/L KCl for three days, the nitrogen-fixing activity ofAnabaena cylindrica decreased by 95%. Extent of the inhibition was enchanced with increased KCl concentrations. The bigges...Growing in the medium containing 0.10 mol/L KCl for three days, the nitrogen-fixing activity ofAnabaena cylindrica decreased by 95%. Extent of the inhibition was enchanced with increased KCl concentrations. The biggest decrease of nitrogen-fixing activity was between 0.02–0.05 mol/L KCl. The same decline on growth was between 0.05–0.10 mol/L KCl. The longer treating-time was, the lower nitrogen-fixing activity was. A short time of KCl-treatment (for 4 h) resulted in 66.4%decrease of the activity. Under effecting of KCl for three days, the frequency of heterocyst differentiation decreased from 7.2%to 2.1%.展开更多
Prevention of nitrogen porosity in weld metal deposited with self-shielded flux cored wire with CaF2-TiO2-MgO slag system can be accomplished by using a 'killing agent' such as titanium to react with nitrogen ...Prevention of nitrogen porosity in weld metal deposited with self-shielded flux cored wire with CaF2-TiO2-MgO slag system can be accomplished by using a 'killing agent' such as titanium to react with nitrogen dissolved in the weld metal. The amount of titanium needed to prevent porosity is calculated thermodynamically for various dissolved nitrogen levels. Experimental flux cored wires are used to verify the thermodynamic model. It is concluded that approximately 0.11 wt% titanium in the weld deposit is need to prevent nitrogen porosity when welding without externally applied shielding.展开更多
Modular unit systems provide an eco-friendly advanced construction method that improves productivity and reduces carbon emissions and construction waste. In these systems, the prefabrication ratio of the modules shoul...Modular unit systems provide an eco-friendly advanced construction method that improves productivity and reduces carbon emissions and construction waste. In these systems, the prefabrication ratio of the modules should be high in order to support these eco-friendly features. The purpose of this study was to verify the functionality and driving safety of fixing a modular unit with a high prefabrication ratio to a vehicle for transportation to the site using two novel adapter blocks specially developed for this purpose. When asked to evaluate their performance for this study, the truck drivers selected adaptor block type B as providing the highest convenience and functionality. In real-world driving experiments, maximum loads of 15 kN and 25 kN were measured on adapter block types A and B, respectively. Future improvements in the adapter blocks that take the safety ratio and the improved convenience of use into account are confidently expected to contribute to the eco-friendliness and the improved productivity of modular unit systems.展开更多
Environmental pollution has seriously damaged the health of mankind and the development of future generations. Because pollution damages are irreversible, taking effective measures to prevent contamination accidents i...Environmental pollution has seriously damaged the health of mankind and the development of future generations. Because pollution damages are irreversible, taking effective measures to prevent contamination accidents is the primary task for administrative penalty on environmental pollution. However, the specific amount of such penalty is a little bit on the low side, and the standard for fixing the penalty is not rational somewhat. As a result, the original functions and purpose of administrative penalty on environmental pollution cannot be fully achieved. By comparing and using for reference related systems at home and abroad, this paper advances the drawbacks and suggestions for the amount fixing of China’s administrative penalty on environmental pollution in the hope of supplying theoretical basis for the improvement of China’s administrative penalty mechanism on environmental pollution.展开更多
Concrete pump pipe pulse force fixed device is one of the important equipment in engineering construction. Its role is to transport mixed concrete. Concrete pump pipe pulse force fixed device is particularly important...Concrete pump pipe pulse force fixed device is one of the important equipment in engineering construction. Its role is to transport mixed concrete. Concrete pump pipe pulse force fixed device is particularly important in high-rise buildings, because it can save labors, and improve the production efficiency of engineering construction. However, when pumping concrete, the pump pipe will produce strong impulse impact force, which may lead to pump pipe rupture and support system instability collapse accident, resulting in casualties, and it is easy to destroy the cross-section size of the formwork and cause the deviation of the position of the structural reinforcement, affecting the quality of concrete, thereby endangering the safety of the structure. For this purpose, the pump pipe needs to be fixed. The existing fixing method is to reinforce the pump pipe through the well-shaped scaffold, which is mostly rigid structure, and the impact force produced by the pump pipe in the pumping process is easy to damage the pump pipe. Based on the above research, this paper explores the invention of a reusable pulse force fixing device for concrete pump pipe, hoping to be helpful to other workers in the concrete industry.展开更多
Let （M, T） be a closed manifold with an involution T. The fixed point set of T is F. In this article, bordism classes of the involutions with fixed point set F = ^mUi=1 CPi（1）×HPi（n） are determined, where C...Let （M, T） be a closed manifold with an involution T. The fixed point set of T is F. In this article, bordism classes of the involutions with fixed point set F = ^mUi=1 CPi（1）×HPi（n） are determined, where CP（1） and HP（n） denote the 1-dimensional i=1 complex projective space and n-dimensional quaternionic projective space respectively, and n=2^p-2or n=2^p-1（p〉 1）.展开更多
Are you tred of regular selfies?Try a self-photo studio!The lights and camera are ready for you.At the studio,you can fix your hair.There are clothes and props.You can use those and take fun photos.Bring your friends ...Are you tred of regular selfies?Try a self-photo studio!The lights and camera are ready for you.At the studio,you can fix your hair.There are clothes and props.You can use those and take fun photos.Bring your friends with you.Then you can take photos together.Pose in silly ways and have fun!You can take the photos home and remember your good time.展开更多
The triple bond in N_(2)has an extremely high bond energy and is thus difficult to break.N_(2)is commonly converted into NH3 artificially via the Haber-Bosch process,and NH_(3)can be utilized to produce other nitrogen...The triple bond in N_(2)has an extremely high bond energy and is thus difficult to break.N_(2)is commonly converted into NH3 artificially via the Haber-Bosch process,and NH_(3)can be utilized to produce other nitrogen-containing chemicals.Here,we developed an electron catalyzed method to directly fix N_(2)into azos,by pushing and pulling the electron into and from the aromatic halide with the cyclic voltammetry method.The round-trip journey of electron can successfully weaken the triple bond in N_(2)through the electron pushing-induced aryl radical via a“brick trowel”transition state,and then produce the diazonium ions by pulling the electron out from the diazo radical intermediate.Different azos can be synthesized with this developed electron catalyzed approach.This approach provides a novel concept and practical route for the fixation of N_(2)at atmospheric pressure into chemical products valuable for industrial and commercial applications.展开更多
Let X be a closed simply connected rationally elliptic 4-manifold.The rational homotopy type of homotopy fixed point sets X^(hS^(1))is determined,and based on some relations between X^(hS^(1))and X^(S^(1)),the rationa...Let X be a closed simply connected rationally elliptic 4-manifold.The rational homotopy type of homotopy fixed point sets X^(hS^(1))is determined,and based on some relations between X^(hS^(1))and X^(S^(1)),the rational homotopy type of the fixed point set X^(S^(1))is determined.展开更多
In this paper,we establish common fixed point theorems for expansive map?pings on b-metric-like space and coincidence point for f-weakly isotone increasing mappings in partially ordered b-metric-like space.The main re...In this paper,we establish common fixed point theorems for expansive map?pings on b-metric-like space and coincidence point for f-weakly isotone increasing mappings in partially ordered b-metric-like space.The main results generalize and extend several well-known comparable results from the existing literature.Moreover,some examples are provided to illustrate the main results.展开更多
Maize(Zea mays)requires substantial amounts of nitrogen,posing a challenge for its cultivation.Recent work discovered that some ancient Mexican maize landraces harbored diazotrophic bacteria in mucilage secreted by th...Maize(Zea mays)requires substantial amounts of nitrogen,posing a challenge for its cultivation.Recent work discovered that some ancient Mexican maize landraces harbored diazotrophic bacteria in mucilage secreted by their aerial roots.To see if this trait is retained in modern maize,we conducted a field study of aerial root mucilage(ARM)in 258 inbred lines.We observed that ARM secretion is common in modern maize,but the amount significantly varies,and only a few lines have retained the nitrogen‐fixing traits found in ancient landraces.The mucilage of the high‐ARM inbred line HN5‐724 had high nitrogen‐fixing enzyme activity and abundant diazotrophic bacteria.Our genome‐wide association study identified 17 candidate genes associated with ARM across three environments.Knockouts of one candidate gene,the subtilase family gene ZmSBT3,confirmed that it negatively regulates ARM secretion.Notably,the ZmSBT3 knockout lines had increased biomass and total nitrogen accumulation under nitrogen‐free culture conditions.High ARM was associated with three ZmSBT3 haplotypes that were gradually lost during maize domestication,being retained in only a few modern inbred lines such as HN5‐724.In summary,our results identify ZmSBT3 as a potential tool for enhancing ARM,and thus nitrogen fixation,in maize.展开更多
Feature models have been widely adopted to reuse the requirements of a set of similar products in a domain. In feature models＇ construction, one basic task is to ensure the consistency of feature models, which often ...Feature models have been widely adopted to reuse the requirements of a set of similar products in a domain. In feature models＇ construction, one basic task is to ensure the consistency of feature models, which often involves detecting and fixing of inconsistencies in feature models. While many approaches have been proposed, most of them focus on detecting inconsistencies rather than fixing inconsistencies. In this paper, we propose a novel dynamic-priority based approach to interactively fixing inconsistencies in feature models, and report an implementation of a system that not only automatically recommends a solution to fixing inconsistencies but also supports domain analysts to gradually reach the desirable solution by dynamically adjusting priorities of constraints. The key technical contribution is, as far as we are aware, the first application of the constraint hierarchy theory to feature modeling, where the degree of domain analysts＇ confidence on constraints is expressed by using priority and inconsistencies are resolved by deleting one or more lower-priority constraints. Two case studies demonstrate the usability and scalability （efficiency） of our new approach.展开更多
This paper presents an attempt to develop a new system for fixing carbon dioxide from the atmosphere.The proposed molecular system has been designed to have the capacity to spontaneously bind CO_(2)from the atmosphere...This paper presents an attempt to develop a new system for fixing carbon dioxide from the atmosphere.The proposed molecular system has been designed to have the capacity to spontaneously bind CO_(2)from the atmosphere with high affinity.The molecular system is furthermore designed to have the ability to liberate CO_(2)at a later stage in the process,i.e.,in a separate compartment.The liberated CO_(2)presents a carbon neutral way of obtaining pure CO_(2).The proposed molecular system is based on a small stable organic molecule that potentially have two forms:one without bound CO_(2)and one with bound CO_(2).One class of molecules that undergo a reaction compatible with our purposal is the merocyanine dyes that exhibit photochromic properties.Based on this structural class of molecules,a system for the potential fixing of CO_(2)has been developed.展开更多
文摘The study, conducted at the Research Farm of the College of Agriculture, University of Tabriz in 2021, focused on the effects of various nitrogen-fixing bacterial isolates, biofertilizers containing nitrogen and phosphorus, as well as iron and zinc foliar applications on mustard growth under rainfed conditions. The results indicated that biofertilizers, whether used alone or in combination with chemical fertilizers, produced comparable grain and oil outputs compared to chemical fertilizers alone. Additionally, the application of iron and zinc through foliar spraying significantly enhanced both grain and oil production. These findings suggest that integrating nitrogen-fixing bacteria and biofertilizers could reduce reliance on chemical nitrogenous fertilizers, leading to decreased production expenses, improved product quality, and minimized environmental impact. This study highlights the potential for sustainable agricultural practices in dry land farming as a viable alternative to traditional chemical-intensive methods. Substituting chemical nitrogenous fertilizers with nitrogen-fixing bacteria or biofertilizers could result in cost savings in mustard grain and oil production while promoting environmental sustainability.
基金supported by the High-Speed Railway Basic Research Fund Key Project of China(Grant No.U1234208)the National Natural Science Foundation of China(Grant Nos.51475394 and 51605397)
文摘To study the influence of the pantograph fixing position on aerodynamic characteristics of high-speed trains, the aerodynamic models of high-speed trains with eight cars were established based on the theory of com- putational fluid dynamics, and eight cases with pantographs fixed on different positions and in different operational orientations were considered. The pantographs were fixed on the front or the rear end of the first middle car or fixed on the front or the rear end of the last middle car. The external flow fields of the high-speed trains were numeri- cally simulated using the software STAR-CCM＋. The results show that the pantograph fixing position has little effect on the aerodynamic drag force of the head car and has a large effect on the aerodynamic drag force of the tail car. The influences of the pantograph fixing position on the aerodynamic lift forces of the head car, tail car and pan- tographs are obvious. Among the eight cases, considering the total aerodynamic drag force of the train and the aerodynamic lift force of the lifted pantograph, when the pantographs are fixed on the rear end of the last middle car and the lifted pantograph is in the knuckle-upstream ori- entation, the aerodynamic performance of the high-speed train is the best.
基金supported by the National Natural Science Foundation of China (Nos.21177093,21307093)the National High Technology Research and Development Program of China (No.2012AA050101)+3 种基金the Research Fund for the Doctoral Program of Higher Education of China (No.20130072110025)China Postdoctoral Science Foundation (Nos.2013M531220,121656)the State Key Laboratory of Pollution Control and Resource Reuse Foundation (No.PCRRY12002)the Collaborative Innovation Center for Regional Environmental Quality
文摘The universality of improved CO2 fixing upon the addition of mixed electron donors（MEDs）composed of Na2 S,NO2-,and S2O32-to non-photosynthetic microbial communities（NPMCs）obtained from 12 locations in four oceans of the world was validated. The CO2 fixing efficiencies of NPMCs were universally enhanced by MED compared with those obtained using H2 alone as electron donor,with average increase of about 276%. An increase in microbial inoculation concentration could increase the net amount of CO2 fixing to853.34 mg/L in the presence of MED. NO2-and S2O32-may play the roles of both electron acceptor and electron donor under aerobic conditions,which may improve the energy utilization efficiency of NPMC and enhance the CO2 fixation efficiency. The sequence determination of 16 S ribosomal deoxyribonucleic acid（rDNA） from 150 bacteria of NPMC showed that more than 50% of the bacteria were symbiotic and there were many heterotrophic bacteria such as Vibrio natriegens. These results indicate that NPMC acts as a symbiotic CO2 fixing system. The interaction between autotrophic and heterotrophic bacteria may be a crucial factor supporting ladder utilization and recycling of energy/carbon source.
文摘Mangrove provides a unique ecological niche to different microbes which play various roles in nutrient recycling as well as various environmental activities. The highly productive and diverse microbial community living in mangrove ecosystems continuously transforms dead vegetation and recycle nitrogen, phosphorus, sulphur and other nutrients that can later be used by the plants. Mangrove ecosystems are rich in organic matter, and however, in general, they are nutrient-deficient ecosystems, especially of nitrogen and phosphorus. The present study investigated depth wise variation of Nitrifying bacteria, Nitrogen fixing bacteria, total bacterial population along with nitrate-nitrogen, nitrite-nitrogen and other physicochemical parameters of soil during pre-monsoon, monsoon and post-monsoon periods at three different sampling stations of mangrove sediments viz. deep forest region, rooted region and unrooted region. The microbial population was also found maximum in the deep forest sediment relative to the other two sites. Populations of cultureable microbes were found maximum in surface soil and decreased with increase in depth in Sundarban mangrove environment. A decreasing trend of total microbial load, nitrifying and nitrogen fixing bacteria with increase in depth were recorded throughout the year. Present study revealed the relationship among depth integrated variations of physicochemical components (viz. soil temperature, pH, salinity, nitrite nitrogen and nitrate nitrogen concentration) and total microbial load, nitrifying and nitrogen fixing bacteria microbial populations.
基金Supported by the National Natural Science Foundation of China (50364003)
文摘As special cylindrical briquettes of coal for long distance pipeline transportation and directly cleaned combustion the cleaned coal logs should possess two characteristics of transportation in pipeline and cleaned combustion. In order to make cleaned coal logs a rational technology for manufacturing, cleaned coal logs was designed and compound sulfur fixing binders with high effects of binding and sulfur-fixing was selected and combined. In addition, by means of characteristic experiments of strength, wear, waterproof and sulfur-fixing five different cleaned coal logs made with different compound sulfur fixing binders in different compaction conditions was tested and measured. Experimental results indicated that the manufacturing technology of cleaned coal logs was reasonable and the combination of compound sulfur fixing binders was scientific. Cleaned coal logs made up with the fourth group of coal mixture had high strength, good waterproof property, efficient sulfur-fixing, good characteristic of transportation, and achieved the performance requirement for pipeline transportation and sulfur fixing.
文摘There are two connection modes between escalator step and step drive chain of outer roller,connector type A and type B.Connector type B after a period of running was found that the fixing bolt on the connector has loosened,which causes safety risks.In order to eliminate this security issue,the finite element modeling is proposed to analyze the relationship between the force generated by the connector type A or type B during the step band running and the assembly clearance or the assembly mode.So as to find out the root cause of fixing bolt loosening phenomenon,by redesigning the assembly clearance between the connector shaft and the chain hole,the fixing bolt of the connector is prevented from loosening during the step band running,ensuring the safe operation of escalators to avoid injury accidents.
基金The Natural Science Foundation of Zhejiang Province, China(No. M303106)
文摘There has always been a great need for simple and accurate bioassays for evaluating nutrient limitation in aquatic ecosystems. Whereas organic carbon is usually considered to be the limiting nutrient for microbial growth in many aquatic ecosystems, there are, however, many water sources that are limited by phosphorus or nitrogen. A method named ＂nitrogen fixing bacterial growth potential＂ （NFBGP） test, which is based on pre-culturing of autochthonous （target） microorganisms was described. The method was applied to evaluate phosphorus or nitrogen nutrient limitation in lake and sewage water samples using an isolate of the nitrogen fixing bacterium, Azorhizobium sp. WS6. The results corresponded well to those from the traditional algal growth potential （AGP） test and the bacterial regrowth potential （BRP） test, suggesting that the NFBGP test is a useful supplementary method for evaluating the limiting nutrient, especially phosphorus, in an aquatic environment.
文摘Growing in the medium containing 0.10 mol/L KCl for three days, the nitrogen-fixing activity ofAnabaena cylindrica decreased by 95%. Extent of the inhibition was enchanced with increased KCl concentrations. The biggest decrease of nitrogen-fixing activity was between 0.02–0.05 mol/L KCl. The same decline on growth was between 0.05–0.10 mol/L KCl. The longer treating-time was, the lower nitrogen-fixing activity was. A short time of KCl-treatment (for 4 h) resulted in 66.4%decrease of the activity. Under effecting of KCl for three days, the frequency of heterocyst differentiation decreased from 7.2%to 2.1%.
文摘Prevention of nitrogen porosity in weld metal deposited with self-shielded flux cored wire with CaF2-TiO2-MgO slag system can be accomplished by using a 'killing agent' such as titanium to react with nitrogen dissolved in the weld metal. The amount of titanium needed to prevent porosity is calculated thermodynamically for various dissolved nitrogen levels. Experimental flux cored wires are used to verify the thermodynamic model. It is concluded that approximately 0.11 wt% titanium in the weld deposit is need to prevent nitrogen porosity when welding without externally applied shielding.
文摘Modular unit systems provide an eco-friendly advanced construction method that improves productivity and reduces carbon emissions and construction waste. In these systems, the prefabrication ratio of the modules should be high in order to support these eco-friendly features. The purpose of this study was to verify the functionality and driving safety of fixing a modular unit with a high prefabrication ratio to a vehicle for transportation to the site using two novel adapter blocks specially developed for this purpose. When asked to evaluate their performance for this study, the truck drivers selected adaptor block type B as providing the highest convenience and functionality. In real-world driving experiments, maximum loads of 15 kN and 25 kN were measured on adapter block types A and B, respectively. Future improvements in the adapter blocks that take the safety ratio and the improved convenience of use into account are confidently expected to contribute to the eco-friendliness and the improved productivity of modular unit systems.
文摘Environmental pollution has seriously damaged the health of mankind and the development of future generations. Because pollution damages are irreversible, taking effective measures to prevent contamination accidents is the primary task for administrative penalty on environmental pollution. However, the specific amount of such penalty is a little bit on the low side, and the standard for fixing the penalty is not rational somewhat. As a result, the original functions and purpose of administrative penalty on environmental pollution cannot be fully achieved. By comparing and using for reference related systems at home and abroad, this paper advances the drawbacks and suggestions for the amount fixing of China’s administrative penalty on environmental pollution in the hope of supplying theoretical basis for the improvement of China’s administrative penalty mechanism on environmental pollution.
文摘Concrete pump pipe pulse force fixed device is one of the important equipment in engineering construction. Its role is to transport mixed concrete. Concrete pump pipe pulse force fixed device is particularly important in high-rise buildings, because it can save labors, and improve the production efficiency of engineering construction. However, when pumping concrete, the pump pipe will produce strong impulse impact force, which may lead to pump pipe rupture and support system instability collapse accident, resulting in casualties, and it is easy to destroy the cross-section size of the formwork and cause the deviation of the position of the structural reinforcement, affecting the quality of concrete, thereby endangering the safety of the structure. For this purpose, the pump pipe needs to be fixed. The existing fixing method is to reinforce the pump pipe through the well-shaped scaffold, which is mostly rigid structure, and the impact force produced by the pump pipe in the pumping process is easy to damage the pump pipe. Based on the above research, this paper explores the invention of a reusable pulse force fixing device for concrete pump pipe, hoping to be helpful to other workers in the concrete industry.
基金supported by NSFC (1097105011001073+3 种基金10901045)HNSFC(A2010000828)FHUST (XL201043QD201021)
文摘Let （M, T） be a closed manifold with an involution T. The fixed point set of T is F. In this article, bordism classes of the involutions with fixed point set F = ^mUi=1 CPi（1）×HPi（n） are determined, where CP（1） and HP（n） denote the 1-dimensional i=1 complex projective space and n-dimensional quaternionic projective space respectively, and n=2^p-2or n=2^p-1（p〉 1）.
文摘Are you tred of regular selfies?Try a self-photo studio!The lights and camera are ready for you.At the studio,you can fix your hair.There are clothes and props.You can use those and take fun photos.Bring your friends with you.Then you can take photos together.Pose in silly ways and have fun!You can take the photos home and remember your good time.
文摘The triple bond in N_(2)has an extremely high bond energy and is thus difficult to break.N_(2)is commonly converted into NH3 artificially via the Haber-Bosch process,and NH_(3)can be utilized to produce other nitrogen-containing chemicals.Here,we developed an electron catalyzed method to directly fix N_(2)into azos,by pushing and pulling the electron into and from the aromatic halide with the cyclic voltammetry method.The round-trip journey of electron can successfully weaken the triple bond in N_(2)through the electron pushing-induced aryl radical via a“brick trowel”transition state,and then produce the diazonium ions by pulling the electron out from the diazo radical intermediate.Different azos can be synthesized with this developed electron catalyzed approach.This approach provides a novel concept and practical route for the fixation of N_(2)at atmospheric pressure into chemical products valuable for industrial and commercial applications.
文摘Let X be a closed simply connected rationally elliptic 4-manifold.The rational homotopy type of homotopy fixed point sets X^(hS^(1))is determined,and based on some relations between X^(hS^(1))and X^(S^(1)),the rational homotopy type of the fixed point set X^(S^(1))is determined.
基金Supported by the National Natural Science Foundation of China(12001249)the Natural Science Foundation of Jiangxi Province(20232BAB211004)the Educational Commission Science Programm of Jiangxi Province(GJJ2200523)。
文摘In this paper,we establish common fixed point theorems for expansive map?pings on b-metric-like space and coincidence point for f-weakly isotone increasing mappings in partially ordered b-metric-like space.The main results generalize and extend several well-known comparable results from the existing literature.Moreover,some examples are provided to illustrate the main results.
基金the special fund at Henan Agricultural University
文摘Maize(Zea mays)requires substantial amounts of nitrogen,posing a challenge for its cultivation.Recent work discovered that some ancient Mexican maize landraces harbored diazotrophic bacteria in mucilage secreted by their aerial roots.To see if this trait is retained in modern maize,we conducted a field study of aerial root mucilage(ARM)in 258 inbred lines.We observed that ARM secretion is common in modern maize,but the amount significantly varies,and only a few lines have retained the nitrogen‐fixing traits found in ancient landraces.The mucilage of the high‐ARM inbred line HN5‐724 had high nitrogen‐fixing enzyme activity and abundant diazotrophic bacteria.Our genome‐wide association study identified 17 candidate genes associated with ARM across three environments.Knockouts of one candidate gene,the subtilase family gene ZmSBT3,confirmed that it negatively regulates ARM secretion.Notably,the ZmSBT3 knockout lines had increased biomass and total nitrogen accumulation under nitrogen‐free culture conditions.High ARM was associated with three ZmSBT3 haplotypes that were gradually lost during maize domestication,being retained in only a few modern inbred lines such as HN5‐724.In summary,our results identify ZmSBT3 as a potential tool for enhancing ARM,and thus nitrogen fixation,in maize.
基金supported by the National High Technology Research and Development 863 Program of China under Grant No.2013AA01A605the National Basic Research 973 Program of China under Grant No.2011CB302604+1 种基金the National Natural Science Foundation of China under Grant Nos.61121063,U1201252,61272163,61202071,and 60528006the Japan MEXT Grant-in-Aid for Scientific Research(A)under Grant No.25240009
文摘Feature models have been widely adopted to reuse the requirements of a set of similar products in a domain. In feature models＇ construction, one basic task is to ensure the consistency of feature models, which often involves detecting and fixing of inconsistencies in feature models. While many approaches have been proposed, most of them focus on detecting inconsistencies rather than fixing inconsistencies. In this paper, we propose a novel dynamic-priority based approach to interactively fixing inconsistencies in feature models, and report an implementation of a system that not only automatically recommends a solution to fixing inconsistencies but also supports domain analysts to gradually reach the desirable solution by dynamically adjusting priorities of constraints. The key technical contribution is, as far as we are aware, the first application of the constraint hierarchy theory to feature modeling, where the degree of domain analysts＇ confidence on constraints is expressed by using priority and inconsistencies are resolved by deleting one or more lower-priority constraints. Two case studies demonstrate the usability and scalability （efficiency） of our new approach.
基金supported by the Danish Research Council for Technology and Production Sciences(FTP 274-05-0356).
文摘This paper presents an attempt to develop a new system for fixing carbon dioxide from the atmosphere.The proposed molecular system has been designed to have the capacity to spontaneously bind CO_(2)from the atmosphere with high affinity.The molecular system is furthermore designed to have the ability to liberate CO_(2)at a later stage in the process,i.e.,in a separate compartment.The liberated CO_(2)presents a carbon neutral way of obtaining pure CO_(2).The proposed molecular system is based on a small stable organic molecule that potentially have two forms:one without bound CO_(2)and one with bound CO_(2).One class of molecules that undergo a reaction compatible with our purposal is the merocyanine dyes that exhibit photochromic properties.Based on this structural class of molecules,a system for the potential fixing of CO_(2)has been developed.
